Book or go to the reference desk on the first floor of the Taylor Family Digital Library..
For more information on selecting preliminary sources see:
|
Libraries & Cultural Resources
Online ordering is currently unavailable due to technical issues. We apologise for any delays responding to customers while we resolve this. For further updates please visit our website: https://www.cambridge.org/news-and-insights/technical-incident Due to planned maintenance there will be periods of time where the website may be unavailable. We apologise for any inconvenience.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings .
Decision-making in preliminary engineering design.
Published online by Cambridge University Press: 27 February 2009
A designer often has to deal with complex and ill-structured situations during specification synthesis and preliminary engineering design. To assist in the development of computer-aided design systems, it is desirable to capture the designers decision-making process during these design states. The research presented in this paper is towards this direction. Based on the conceptual understanding of the process, three postulates are presented. The following two postulates; (1) the decisions are neither optimum nor just satisfying but retain certain characteristics of both, (2) the design is driven by the important objective(s) among all the specified objectives, at the preliminary design, although the remaining objectives do have a weak influence on the preliminary design; are used to develop a compensatory and a non-compensatory model of the decision-making. These models are formulated with the help of fuzzy set theory and they implicitly or explicitly follow the two postulates. These models are suitable for discrete decision situations where the above mentioned postulates apply. Examples of material selection during a preliminary structural design are used to illustrate the effectiveness of these models.
View all Google Scholar citations for this article.
To save this article to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle .
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox .
To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive .
- No HTML tags allowed - Web page URLs will display as text only - Lines and paragraphs break automatically - Attachments, images or tables are not permitted
Your email address will be used in order to notify you when your comment has been reviewed by the moderator and in case the author(s) of the article or the moderator need to contact you directly.
Conflicting interests.
Please list any fees and grants from, employment by, consultancy for, shared ownership in or any close relationship with, at any time over the preceding 36 months, any organisation whose interests may be affected by the publication of the response. Please also list any non-financial associations or interests (personal, professional, political, institutional, religious or other) that a reasonable reader would want to know about in relation to the submitted work. This pertains to all the authors of the piece, their spouses or partners.
Research output : Contribution to journal › Article › peer-review
A designer often has to deal with complex and ill-structured situations during specification synthesis and preliminary engineering design. To assist in the development of computer-aided design systems, it is desirable to capture the designers decision-making process during these design states. The research presented in this paper is towards this direction. Based on the conceptual understanding of the process, three postulates are presented. The following two postulates; (1) the decisions are neither optimum nor just satisfying but retain certain characteristics of both, (2) the design is driven by the important objective(s) among all the specified objectives, at the preliminary design, although the remaining objectives do have a weak influence on the preliminary design; are used to develop a compensatory and a non-compensatory model of the decision-making. These models are formulated with the help of fuzzy set theory and they implicitly or explicitly follow the two postulates. These models are suitable for discrete decision situations where the above mentioned postulates apply. Examples of material selection during a preliminary structural design are used to illustrate the effectiveness of these models.
Original language | English (US) |
---|---|
Pages (from-to) | 21-30 |
Number of pages | 10 |
Journal | |
Volume | 5 |
Issue number | 1 |
DOIs | |
State | Published - Feb 1991 |
T1 - Decision-making in preliminary engineering design
AU - Joshi, S. P.
AU - Umaretiya, J. R.
AU - Joshi, Sanjay B.
PY - 1991/2
Y1 - 1991/2
N2 - A designer often has to deal with complex and ill-structured situations during specification synthesis and preliminary engineering design. To assist in the development of computer-aided design systems, it is desirable to capture the designers decision-making process during these design states. The research presented in this paper is towards this direction. Based on the conceptual understanding of the process, three postulates are presented. The following two postulates; (1) the decisions are neither optimum nor just satisfying but retain certain characteristics of both, (2) the design is driven by the important objective(s) among all the specified objectives, at the preliminary design, although the remaining objectives do have a weak influence on the preliminary design; are used to develop a compensatory and a non-compensatory model of the decision-making. These models are formulated with the help of fuzzy set theory and they implicitly or explicitly follow the two postulates. These models are suitable for discrete decision situations where the above mentioned postulates apply. Examples of material selection during a preliminary structural design are used to illustrate the effectiveness of these models.
AB - A designer often has to deal with complex and ill-structured situations during specification synthesis and preliminary engineering design. To assist in the development of computer-aided design systems, it is desirable to capture the designers decision-making process during these design states. The research presented in this paper is towards this direction. Based on the conceptual understanding of the process, three postulates are presented. The following two postulates; (1) the decisions are neither optimum nor just satisfying but retain certain characteristics of both, (2) the design is driven by the important objective(s) among all the specified objectives, at the preliminary design, although the remaining objectives do have a weak influence on the preliminary design; are used to develop a compensatory and a non-compensatory model of the decision-making. These models are formulated with the help of fuzzy set theory and they implicitly or explicitly follow the two postulates. These models are suitable for discrete decision situations where the above mentioned postulates apply. Examples of material selection during a preliminary structural design are used to illustrate the effectiveness of these models.
UR - http://www.scopus.com/inward/record.url?scp=84972016385&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84972016385&partnerID=8YFLogxK
U2 - 10.1017/S0890060400002511
DO - 10.1017/S0890060400002511
M3 - Article
AN - SCOPUS:84972016385
SN - 0890-0604
JO - Artificial Intelligence for Engineering, Design, Analysis and Manufacturing
JF - Artificial Intelligence for Engineering, Design, Analysis and Manufacturing
An official website of the United States government
The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.
The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.
Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .
Wenlong huang.
Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
NC3Rs, London, UK
Preclinical studies using animals to study the potential of a therapeutic drug or strategy are important steps before translation to clinical trials. However, evidence has shown that poor quality in the design and conduct of these studies has not only impeded clinical translation but also led to significant waste of valuable research resources. It is clear that experimental biases are related to the poor quality seen with preclinical studies. In this chapter, we will focus on hypothesis testing type of preclinical studies and explain general concepts and principles in relation to the design of in vivo experiments, provide definitions of experimental biases and how to avoid them, and discuss major sources contributing to experimental biases and how to mitigate these sources. We will also explore the differences between confirmatory and exploratory studies, and discuss available guidelines on preclinical studies and how to use them. This chapter, together with relevant information in other chapters in the handbook, provides a powerful tool to enhance scientific rigour for preclinical studies without restricting creativity.
This chapter will give an overview of some generic concepts pertinent to the design of preclinical research. The emphasis is on the requirements of in vivo experiments which use experimental animals to discover and validate new clinical therapeutic approaches. However, these general principles are, by and large, generically relevant to all areas of preclinical research. The overarching requirement should be that preclinical research should only be conducted to answer an important question for which a robust scrutiny of the available evidence demonstrates that the answer is not already known. Furthermore, such experiments must be designed, conducted, analysed and reported to the highest levels of rigour and transparency. Assessments of research outputs should focus more on these factors and less on any apparent “novelty”.
Broadly, preclinical research can be classified into two distinct categories depending on the aim and purpose of the experiment, namely, “hypothesis generating” (exploratory) and “hypothesis testing” (confirmatory) research ( Fig. 1 ). Hypothesis generating studies are often scientifically-informed, curiosity and intuition-driven explorations which may generate testable theories regarding the pathophysiology of disease and potential drug targets. The freedom of researchers to explore such innovative ideas is the lifeblood of preclinical science and should not be stifled by excessive constraints in terms of experimental design and conduct. Nevertheless, in order to subsequently assess the veracity of hypotheses generated in this way, and certainly to justify clinical development of a therapeutic target, hypothesis testing studies which seek to show reproducible intervention effects in relevant animal models must be designed, conducted, analysed and reported to the highest possible levels of rigour and transparency. This will also contribute to reducing research “waste” ( Ioannidis et al. 2014 ; Macleod et al. 2014 ). Chapter “Resolving the Tension Between Exploration and Confirmation in Preclinical Biomedical Research” of the handbook will deal with exploratory and confirmatory studies in details. This chapter will only focus on general design principles for hypothesis testing studies. We will address the issue of design principles for hypothesis-generating studies at the end of this chapter. We advise that when researchers design and conduct hypothesis testing in vivo studies, they should conform to the general principles for the major domains that are outlined in Sect. 4 of the chapter and incorporate these principles into a protocol that can be registered and published. The purpose of using these principles is to enhance scientific rigour without restricting creativity. It is advisable that sometimes there can be exploratory elements within the same hypothesis testing studies; therefore, extra care in terms of applying these principles to reduce experimental biases would be needed before the start of the studies. This chapter will not cover reporting, which will be detailed in chapters “Minimum Information and Quality Standards for Conducting, Reporting, and Organizing In Vitro Research”, “Minimum Information in In Vivo Research”, and “Quality Governance in Biomedical Research” of the handbook.
Comparison of exploratory (hypothesis generating) and confirmatory (hypothesis testing) preclinical studies. Descriptive statistics describes data and provides descriptions of the population, using numerical calculations, graphs, and tables. In contrast, inferential statistics predicts and infers about a population using a sample of data from the population, therefore one can take data from samples and make generalisation about a population
We would recommend that researchers who conduct hypothesis testing in vivo studies should prepare clear protocols, which include a statistical analysis plan, detailing how they are going to set up measures to address the major domains of experimental biases before the experiments start. Ideally, these protocols should be preregistered and/or published, so that the methods which will be used to reduce the impact of bias are documented in an a priori fashion. The process of peer review of a protocol prior to initiating experiments of course is a valuable opportunity for refinement and improvement. Registering protocols encourages rigour and transparency, even if the protocol is not peer-reviewed. Some journals are open to submissions of these types of protocols, such as BMJ Open Science, and many journals offer the Registered Reports format. In addition, there are online resources that allow researchers to preregister their experimental protocols, such as preclinical. eu and osf.io/registries.
Designing an in vivo experiment involves taking a number of decisions on different aspects of the experimental plan. Typically, a comparative experiment can be broken into several component parts.
The objective is usually to test a hypothesis. On some occasions, two hypotheses may be postulated: the null hypothesis and the alternative hypothesis. The alternative hypothesis refers to the presumption that the experimental manipulation has an effect on the response measured; the null hypothesis is the hypothesis of no change, or no effect. In a statistical test, the p-value reports the probability of observing an effect as large or larger than the one being observed if the null hypothesis was true; the smaller the p -value, the least likely it is that the null hypothesis is true. The null hypothesis cannot be accepted or proven true. This also defines the effect of interest, i.e. the outcome that will be measured to test the hypothesis. The minimum effect size is the smallest effect the researcher designs the experiment to be able to detect and should be declared in the protocol; it is set up as the minimum difference which would be of biological relevance. The effect size is then used in the sample size calculation to ensure that the experiment is powered to detect only meaningful effects and does not generate statistically significant results that are not biologically relevant. In many cases, it will be hard to determine the minimum difference of biological relevance as for early stage experiments it might be completely unknown, or translatability between clinical relevance and experimental detection thresholds will be complex. There is no simple and easy answer to this question, but in general, a minimum effect size should be set so one can assume to have a beneficial effect for individuals rather than large cohorts, the difference must be experimentally testable and reasonable to achieve, and should have a rationale for translation into patients in the long run.
In comparative experiments, animals are split into groups, and each group is subjected to different interventions, such as a drug or vehicle injection, or a surgical procedure. The sample size is the number of experimental units per group; identifying the experimental unit underpins the reliability of the experiment, but it is often incorrectly identified ( Lazic et al. 2018 ). The experimental unit is the entity subjected to an intervention independently of all other units; it must be possible to assign any two experimental units to different comparison groups. For example, if the treatment is applied to individual mice by injection, the experimental unit may be the animal, in which case the number of experimental units per group and the number of animals per group is the same. However, if there is any contamination between mice within a cage, the treatment given to one mouse might influence other mice in that cage, and it would be more appropriate to subject all mice in one cage to the same treatment and treat the cage as the experimental unit. In another example, if the treatment is added to the water in a fish tank, two fish in the same tank cannot receive different treatments; thus the experimental unit is the tank, and the sample size is the number of tanks per group. Once identified, experimental units are allocated to the different comparison groups of the desired sample size; this is done using an appropriate method of randomisation to prevent selection bias (see Sect. 3 ). Each comparison group will be subjected to different interventions, at least one of which will be a control. The purpose of the control group is to allow the researcher to investigate the effect of a treatment and distinguish it from other confounding experimental effects. It is therefore crucial that any control group is treated exactly in the same way as the other comparison groups. Types of control group to consider include negative control, vehicle control, positive control, sham control, comparative control and naïve control ( Bate and Clark 2014 ).
Measurements are taken to assess the results; these are recorded as outcome measures (also known as dependent variable). A number of outcome measures can be recorded in a single experiment, for example, if burrowing behaviour is measured, the outcome measure might be the weight of gravel displaced, or if neuronal density is measured from histological brain slides, the outcome measure might be the neuron count. The primary outcome measure should be identified in the planning stage of the experiment and stated in the protocol; it is the outcome of greatest importance, which will answer the main experimental question. The number of animals in the experiment is determined by the power needed to detect a difference in the primary outcome measure. A hypothesis testing experiment may also include additional outcome measures, i.e. secondary outcome measures, which can be used to generate hypotheses for follow-up experiments. Secondary outcome measures cannot be used to draw conclusions about the experiment if the experiment was not powered to detect a minimum difference for these outcome measures.
For the purpose of the statistical analysis, outcome measures fall into two broad categories: continuous or categorical. Continuous measures are sometimes referred to as quantitative data and are measured on a numerical scale. Continuous measures include truly continuous data but also discrete data. Examples of true continuous data include bodyweight, body temperature, blood/CSF concentration or time to event, while examples of discrete data include litter size, number of correct response or clinical score. Categorical responses are measured on a nonnumerical scale; they can be ordinal (e.g. severity score, mild/moderate/severe), nominal (e.g. behavioural response, left/middle/right arm maze) or binary (e.g. disease state, present/absent). Continuous responses may take longer to measure, but they contain more information. If possible, it is preferable to measure a continuous rather than categorical response because continuous data can be analysed using the parametric analyses, which have higher power; this reduces the sample size needed ( Bate and Clark 2014 ).
There are many ways to analyse data from in vivo experiments; the first step in devising the analysis plan is to identify the independent variables. There can be two broad types: independent variables of interest which the researcher specifically manipulates to test the hypothesis, for example, a drug with different doses, and nuisance variables, which are other sources of variability that may impact on the outcome measure, but are not of direct interest to the researcher. Examples of nuisance variables could be the day of the experiment, if animals used on different days, or baseline body weight or locomotor activity. Every experiment has nuisance variables. Identifying them at the protocol stage and accounting for them in the design and the analysis, for example, as blocking factors, or co-variables, increase the sensitivity of the experiment to detect changes induced by the independent variable(s) of interest. The analysis plan should be established before the experiment starts and any data is collected; it should also be included in the protocol. Additional analyses can be performed on the data, but if an analysis was not planned before the data was collected, it should be clearly reported as a post hoc or exploratory analysis. Exploratory analyses are at greater risk of yielding false positive results.
For any researcher who intends to carry out preclinical in vivo studies, it is important to understand what experimental biases are. First, we need to know the definition of bias. It is the inadequacies in the design, conduct, analysis or reporting of an experiment that cause systematic distortion of the estimated intervention effect away from the “truth” ( Altman et al. 2001 ; van der Worp et al. 2010 ), and it will significantly confound in vivo studies and reduce their internal validity. Sources of bias are multiple and in many cases context dependant. In this overview chapter, it is not possible to give an exhaustive list of potential sources of bias, and it behoves the researcher to systematically identify all potential significant sources of bias for the particular experiment being in planned and to design appropriate mitigation tactics into the protocol. Major known types of biases include selection bias, performance bias, detection bias, and attrition bias. Table 1 gives the definition of each type of bias and describe the methods to reduce them.
Name of bias | Definition of bias | Methods to reduce bias |
---|---|---|
Selection bias | Refers to the biased allocation of animals to different treatment groups, which could happen at the beginning of an animal study or at a stage where reassigning animals to different treatment groups is needed following an initial surgical procedure or treatment. Selection bias results in systematic differences in baseline characteristics between treatment groups ( ) | To avoid systematic differences between animals allocated to different treatment groups, one shall use a valid randomisation method, e.g. a randomisation software or even a simple method such as picking a number from a hat ( ; ; ). Detail for randomisation is covered in chapter “Blinding and Randomization”. Note that it is also necessary to conceal the allocation sequence from experimenters who will assign animals to treatment groups until the time of assignment |
Performance bias | Related to the systematic differences in the care that is provided between different treatment groups or being exposed to factors other than the treatment that could influence the performance of the animals ( ; ; ). Performance bias is a result of animals being managed differently due to, e.g. housing conditions, diet, group sizes per cage, location in the animal house, and experimenters who provide the care to animals are not blinded to treatment groups | One can avoid performance bias by improving the study design, e.g. applying the same housing, diet, location conditions to all the animals and by ensuring proper blinding of the experimenters to treatment groups, which keeps the experimenters who perform the experiment, collect data and access outcomes unaware of treatment allocation. Detail for blinding is covered in chapter “Blinding and Randomization” |
Detection bias | Defined as the systematic distortion of the results of a study that occurs when the experimenter assessing behavioural outcome measures has the knowledge of treatment assignment to groups ( ). In this circumstance, experimenters measuring the outcomes may introduce differential measurement of the outcomes rather than the treatment itself due to inadvertent expectation | The only way to avoid detection bias is a complete blinding of the experimenters, including those who analyse the data, so that they are not aware which animal(s) belong to which treatment group(s). The protocol should define at what stage the blinding codes will be broken (preferably only after data analysis has been completed). Detail for blinding is covered in chapter “Blinding and Randomization” |
Attrition bias | Is the unequal occurrence and handling of deviations from protocol and loss to follow-up between treatment groups ( ). This bias can occur when animals die or are removed from the study due to adverse effects of the treatment or pre-set criteria for removal before observing the outcomes; therefore, the outcomes are not observed for all animals, causing inadvertent bias ( ) | Experimenters should report attrition information for each experimental group and also include outcomes that will not be affected by attrition. It is also advisable to consult a statistician to minimise the impact of attrition bias using some statistical approaches such as intention-to-treat analysis by imputing the missing data. Excluding “outliers” from analysis should be only undertaken as an extremely measure and should only be done to pre-stated criteria. Detail for statistics is covered in chapter “Blinding and Randomization” |
Researchers who conduct hypothesis testing in vivo animal work should understand the importance of limiting the impact of experimental biases in the design, conduct, analysis and reporting of in vivo experiments. Experimental biases can cause significant weakness in the design, conduct and analysis of in vivo animal studies, which can produce misleading results and waste valuable resources. In biomedical research, many effects of interventions are fairly small, and small effects therefore are difficult to distinguish from experimental biases ( Ioannidis et al. 2014 ). Evidence (1960–2012 from PubMed) shows that adequate steps to reduce biases, e.g. blinded assessment of outcome and randomisation, have not been taken in more than 20% and 50% of biomedical studies, respectively, leading to inflated estimates of effectiveness, e.g. in the fields of preclinical stroke, multiple sclerosis, Parkinson’s disease, bone cancer pain and myocardial infarction research ( Currie et al. 2013 ; Macleod et al. 2008 ; Rooke et al. 2011 ; Sena et al. 2007 ; van Hout et al. 2016 ; Vesterinen et al. 2010 ) and consequently significant research waste ( Ioannidis et al. 2014 ; Macleod et al. 2014 , 2015 ). Therefore, it is imperative that biomedical researchers should spend efforts on improvements in the quality of their studies using the methods described in this chapter to reduce experimental biases which will lead to increased effect-to-bias ratio.
However, it is worth pointing out that the notion that experimental biases could significantly impact on in vivo animal studies is often assumed because they are believed to be important in clinical research. Therefore, such an assumption may be flawed, as the body of evidence showing the importance of bias-reducing methods such as randomisation, blinding, etc. for animal studies is still limited and most of the evidence is indirect. Furthermore, there may also be sources of bias which impact on preclinical studies which are currently unknown. Thus, systematic review and metaanalysis of in vivo studies have shown that papers that do not report bias-reducing methods report larger effect sizes ( Vesterinen et al. 2010 ). However, these studies are based on reported data alone, and therefore there might be a difference between what researchers do and what they report in their publications ( Reichlin et al. 2016 ). Reporting of the precise details of bias reduction methods is often scanty, and therefore accurate assessment of the precise method and rigour of such procedures is challenging. Moreover, those papers that do not report one bias-reducing method, e.g. randomisation, also tend to not report other bias-reducing methods, e.g. blinding and sample size calculation, suggesting that there could be interactions between these methods.
In this section, we will describe the major domains, in other words, sources that could contribute to experimental bias if not carefully considered and if mitigating tactics are not included in the design of hypothesis testing experiments before data collection starts. These include sample size estimation, randomisation, allocation concealment, blinding, primary and secondary outcome measures and inclusion/exclusion criteria. General descriptions for these domains ( Macleod et al. 2009 ; Rice et al. 2008 ; Rice 2010 ; van der Worp et al. 2010 ) are shown in the following Table 2 . It is important to note that these domains are key things to be included in a protocol as mentioned in Sect. 1 .
Major domains | General descriptions |
---|---|
Sample size estimation | The sample size refers to the number of experimental units (e.g. a single animal, a cage of animals) per group. In hypothesis testing experiments, it should be determined with a power calculation. Studies that are not appropriately powered are unethical, and both underpowered and overpowered studies lead to a waste of animals. The former because they produce unreliable results and the latter because they use more animals than necessary |
Randomisation | Refers to the steps to reduce systematic differences between comparison groups. Failure to conduct randomisation leads to selection bias |
Allocation concealment | Refers to the practice of concealment of the group or treatment assignment (i.e. the allocation) and its sequence of each experimental unit from the experimenter until the time of assignment. Failure to conceal allocation will lead to selection bias. This should not be confused with randomisation |
Blinding | Refers to the practice of preventing the experimenter who administer treatments, take care of the animals, assess the responses and analyse data from knowing the test condition. Failure of appropriate blinding leads to selection, performance and detection biases |
Primary and secondary outcome measures | Primary outcome measure refers to the outcome measure of most interest, and it is related to the efficacy of an intervention that has the greatest importance for a given study. Secondary outcome measure refers to the outcome measure that is related to intervention efficacy but with less importance than the primary outcome measure and is used to evaluate additional intervention effects. It is important to declare what intervention effects are in the study protocol |
Inclusion/exclusion criteria | Refers to criteria by which animals will be included or excluded in a given study, e.g. due to abnormal baselines or not reaching the required change in thresholds after designed experimental insult |
General principles to reduce experimental bias in each of the above-mentioned domains ( Andrews et al. 2016 ; Knopp et al. 2015 ) are outlined in the following Table 3 .
Major domains | General principles |
---|---|
Sample size estimation | A power calculation (desired power of at least 0.8, and alpha = 0.05) to estimate the experimental group size should be carried out before any hypothesis testing study using pilot data or those relevant data from the literature. This could be done by using a statistical software. Detail on this can be found in chapter “A Reckless Guide to -Values: Local Evidence, Global Errors” |
Randomisation | There are different methods available to randomly allocate animals to experimental groups such as computer-generated randomisation. One should always consider to use the most robust, appropriate and available method for randomisation. Detail on this can be found in chapter “Blinding and Randomization” |
Allocation concealment | Methods should be used to conceal the implementation of the random allocation sequence (e.g. numbered cages) until interventions are assigned, so that the sequence will not be known or predictable in advance by the experimenters involved in allocating animals to the treatment groups |
Blinding | Blinding procedures should be carried out, so that the treatment identity should not be disclosed until after the outcome assessments have been finished for all animals and the primary analysis have been completed. In case that one experimenter conducts the whole study, any additional steps should be taken to preserve the blinding. Detail on this can be found in chapter “Blinding and Randomization” |
Primary and secondary outcome measures | Experimenters should decide the outcome of great importance regarding the treatment efficacy before any study starts as the primary outcome measure. This is also usually used in the sample size estimation. Primary outcome measure cannot be changed once the study starts and when the results are known. Experimenters should also include secondary outcome measures relating to additional effects of treatments; these may be used for new hypothesis generating |
Inclusion/exclusion criteria | Experimenters should set up the exact criteria which will include and exclude animals from their studies. Every animal should be accounted for, except under these criteria. They should be determined appropriately according to the study nature before the studies commence. Once determined, they cannot be changed during the course of investigation |
There are resources to assist investigators in designing rigorous protocols and identify sources of bias. Cross-referencing to experimental reporting guidelines and checklists (e.g. ARRIVE (NC3Rs 2018a) , the NIH guidelines ( NIH 2018a ) and the Nature reporting of animal studies checklist ( Nature 2013 )) can be informative and helpful when planning an experimental protocol. However, it is important to bear in mind that these are primarily designed for reporting purposes and are not specifically designed for use in assisting with experimental design. There are more comprehensive planning guidelines specifically aiming at early experimental design stage. Henderson et al. identified 26 guidelines for in vivo experiments in animals in 2012 ( Henderson et al. 2013 ) (and a few more have been published since, like PREPARE ( Smith et al. 2018 ), developed by the NORECEPA (Norway’s National Consensus Platform for the advancement of the 3Rs), and PPRECISE for the field of pain research ( Andrews et al. 2016 )). Most of them have been developed for a specific research field but carry ideas and principles that can be transferred to all forms of in vivo experiments. Notable are, for example, the very detailed Lambeth Conventions ( Curtis et al. 2013 ) (developed for cardiac arrhythmia research), from Alzheimer’s research recommendations by Shineman et al. (2011) and generally applicable call by Landis et al. (2012) .
The authors of many of these guidelines state that their list might need adaption to the specific experiment. This is pointing out the general shortcoming that a fixed-item list can hardly foresee and account for any possible experimental situation and a blind ticking of boxes ticking of boxes is unlikely to improve experimental design. Such guidelines rather serve an educational purpose of making researchers aware of possible pitfalls and biases before the experimental conduct.
Two examples for a more adaptive and reactive way to serve a similar purpose should be stated: the NIH pages on rigour and reproducibility ( NIH 2018b ) provide in-depth information and collect important publications and workshop updates on these topics and have a funding scheme specifically for rigour and reproducibility. Second, using the Experimental Design Assistant (EDA) ( NC3Rs 2018b ; Percie du Sert et al. 2017 ) developed by the UK’s National Centre for the 3Rs (NC3Rs), a free to use online platform guiding researchers through experimental planning will give researchers the opportunity to adopt guideline and rigour principles precisely to their needs. The researcher creates a flow diagram of their experimental set-up grouped in three domains: the experiment (general questions on hypotheses and aims, animals used, animal strains, etc.), the practical steps (experimental conduct, assessment, etc.) and the analysis stage (e.g. outcome measures, statistical methods, data processing). Unlike a fixed checklist, the EDA checks the specific design as presented by the experimenter within the tool using logic algorithms. The user is then faced with the flaws the EDA identified and can adjust their design accordingly. This process can go through multiple rounds, by that forming a dynamic feedback loop educating the researcher and providing more nuanced assistance than a static checklist can.
While this process, however valid, might take time, the following steps of the EDA actively guide researchers through crucial and complex questions of the experiment, by suggesting fitting methods of statistical analyses of the experiment and subsequently carrying out sample size calculations. The EDA can then also generate a randomization sequence or compile a report of the planned experiment that can, e.g. be part of a preregistration of the experimental protocol.
It is necessary to understand that there are in general two types of preclinical research, namely, exploratory and confirmatory research, respectively. Figure 1 shows that exploratory studies mainly aim to produce theories regarding the pathophysiology of disease (hypothesis generating), while confirmatory studies seek to reproduce exploratory findings as clearly defined intervention effects in relevant animal models (hypothesis testing). The next chapter will deal with exploratory and confirmatory studies in details. Similar standards of rigour are advisable for both forms of studies; this may be achieved by conforming to the general principles for the major domains that are outlined in Table 2 and incorporating these principles into a protocol that can be registered and published. It is important to note that both exploratory and confirmatory research can be closely linked: sometimes there can be exploratory and confirmatory components within the same studies. For example, a newly generated knockout mouse model is used to examine the effect of knockout on one specific phenotype (hypothesis testing–confirmatory) but may also describe a variety of other phenotypic characteristics as well (hypothesis generating–exploratory). Therefore, extra care in terms of applying these principles to reduce experimental bias would be needed before the commence of the studies. It also worth noting that sometimes it might not be compulsory or necessary to use some of the principles during exploratory studies such as sample size estimation and blinding which are albeit of highest importance in confirmatory research.
However, it is necessary to recognise how hypothesis confirming and hypothesis generating research relate to each other: while confirmatory research can turn into exploratory (e.g. if the findings are contrary to the hypothesis, this can lead to a new hypothesis that can be tested in a separate experiment), under no circumstances exploratory findings should be disseminated as the result of hypothesis confirming research by fitting a hypothesis to your results, i.e. to your p -values (often called HARKing = hypothesising after results are known or p -hacking = sifting through a multitude of p -values to find one below 0.05).
In conclusion, this chapter provides general concepts and principles that are important for the design and conduct of preclinical in vivo experiments, including experimental biases and how to reduce these biases in order to achieve the highest levels of rigour for hypothesis generating research using animals. The chapter should be used in conjunction with other relevant chapters in the handbook such as chapters “Blinding and Randomization”, “Minimum Information and Quality Standards for Conducting, Reporting, and Organizing In Vitro Research”, “Minimum Information in In Vivo Research”, “A Reckless Guide to P -Values: Local Evidence, Global Errors”, and “Quality Governance in Biomedical Research”.
Wenlong Huang, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK.
Nathalie Percie du Sert, NC3Rs, London, UK.
Step 5: devise a preliminary outline.
The preliminary outline can serve as your road map for research.
How do you create a preliminary outline? First, realize that all research papers will start with an introduction and end with a conclusion. In between, there are usually three to five points that must be covered in order to answer the question sufficiently.
Suppose this is your research question: "Will stronger gun-control legislation protect lives?" Your preliminary outline might look something like this:
I. Introduction
II. Evidence that gun-control laws protect citizens
III. Evidence that gun-control laws have no effect on civic safety
IV. Analysis of effectiveness of current gun-control laws
V. Conclusion
As you search for books and articles on your topic, you can look for items that will support the various parts of your outline. You can even organize your research results by grouping items according to their usefulness for supporting the different points in your outline.
"For I know the plans I have for you," declares the LORD, "plans to prosper you and not to harm you, plans to give you hope and a future." - Jeremiah 29:11
Vision Statement Building a great Christian university that is pleasing to God by producing Christ-centered servant leaders who are transforming the world.
Run a free plagiarism check in 10 minutes, generate accurate citations for free.
A research paper is a piece of academic writing that provides analysis, interpretation, and argument based on in-depth independent research.
Research papers are similar to academic essays , but they are usually longer and more detailed assignments, designed to assess not only your writing skills but also your skills in scholarly research. Writing a research paper requires you to demonstrate a strong knowledge of your topic, engage with a variety of sources, and make an original contribution to the debate.
This step-by-step guide takes you through the entire writing process, from understanding your assignment to proofreading your final draft.
Upload your document to correct all your mistakes in minutes
Understand the assignment, choose a research paper topic, conduct preliminary research, develop a thesis statement, create a research paper outline, write a first draft of the research paper, write the introduction, write a compelling body of text, write the conclusion, the second draft, the revision process, research paper checklist, free lecture slides.
Completing a research paper successfully means accomplishing the specific tasks set out for you. Before you start, make sure you thoroughly understanding the assignment task sheet:
Carefully consider your timeframe and word limit: be realistic, and plan enough time to research, write, and edit.
The AI-powered Citation Checker helps you avoid common mistakes such as:
There are many ways to generate an idea for a research paper, from brainstorming with pen and paper to talking it through with a fellow student or professor.
You can try free writing, which involves taking a broad topic and writing continuously for two or three minutes to identify absolutely anything relevant that could be interesting.
You can also gain inspiration from other research. The discussion or recommendations sections of research papers often include ideas for other specific topics that require further examination.
Once you have a broad subject area, narrow it down to choose a topic that interests you, m eets the criteria of your assignment, and i s possible to research. Aim for ideas that are both original and specific:
Note any discussions that seem important to the topic, and try to find an issue that you can focus your paper around. Use a variety of sources , including journals, books, and reliable websites, to ensure you do not miss anything glaring.
Do not only verify the ideas you have in mind, but look for sources that contradict your point of view.
In this stage, you might find it helpful to formulate some research questions to help guide you. To write research questions, try to finish the following sentence: “I want to know how/what/why…”
A thesis statement is a statement of your central argument — it establishes the purpose and position of your paper. If you started with a research question, the thesis statement should answer it. It should also show what evidence and reasoning you’ll use to support that answer.
The thesis statement should be concise, contentious, and coherent. That means it should briefly summarize your argument in a sentence or two, make a claim that requires further evidence or analysis, and make a coherent point that relates to every part of the paper.
You will probably revise and refine the thesis statement as you do more research, but it can serve as a guide throughout the writing process. Every paragraph should aim to support and develop this central claim.
Discover proofreading & editing
A research paper outline is essentially a list of the key topics, arguments, and evidence you want to include, divided into sections with headings so that you know roughly what the paper will look like before you start writing.
A structure outline can help make the writing process much more efficient, so it’s worth dedicating some time to create one.
Your first draft won’t be perfect — you can polish later on. Your priorities at this stage are as follows:
You do not need to start by writing the introduction. Begin where it feels most natural for you — some prefer to finish the most difficult sections first, while others choose to start with the easiest part. If you created an outline, use it as a map while you work.
Do not delete large sections of text. If you begin to dislike something you have written or find it doesn’t quite fit, move it to a different document, but don’t lose it completely — you never know if it might come in useful later.
Paragraphs are the basic building blocks of research papers. Each one should focus on a single claim or idea that helps to establish the overall argument or purpose of the paper.
George Orwell’s 1946 essay “Politics and the English Language” has had an enduring impact on thought about the relationship between politics and language. This impact is particularly obvious in light of the various critical review articles that have recently referenced the essay. For example, consider Mark Falcoff’s 2009 article in The National Review Online, “The Perversion of Language; or, Orwell Revisited,” in which he analyzes several common words (“activist,” “civil-rights leader,” “diversity,” and more). Falcoff’s close analysis of the ambiguity built into political language intentionally mirrors Orwell’s own point-by-point analysis of the political language of his day. Even 63 years after its publication, Orwell’s essay is emulated by contemporary thinkers.
It’s also important to keep track of citations at this stage to avoid accidental plagiarism . Each time you use a source, make sure to take note of where the information came from.
You can use our free citation generators to automatically create citations and save your reference list as you go.
APA Citation Generator MLA Citation Generator
The research paper introduction should address three questions: What, why, and how? After finishing the introduction, the reader should know what the paper is about, why it is worth reading, and how you’ll build your arguments.
What? Be specific about the topic of the paper, introduce the background, and define key terms or concepts.
Why? This is the most important, but also the most difficult, part of the introduction. Try to provide brief answers to the following questions: What new material or insight are you offering? What important issues does your essay help define or answer?
How? To let the reader know what to expect from the rest of the paper, the introduction should include a “map” of what will be discussed, briefly presenting the key elements of the paper in chronological order.
The major struggle faced by most writers is how to organize the information presented in the paper, which is one reason an outline is so useful. However, remember that the outline is only a guide and, when writing, you can be flexible with the order in which the information and arguments are presented.
One way to stay on track is to use your thesis statement and topic sentences . Check:
Be aware of paragraphs that seem to cover the same things. If two paragraphs discuss something similar, they must approach that topic in different ways. Aim to create smooth transitions between sentences, paragraphs, and sections.
The research paper conclusion is designed to help your reader out of the paper’s argument, giving them a sense of finality.
Trace the course of the paper, emphasizing how it all comes together to prove your thesis statement. Give the paper a sense of finality by making sure the reader understands how you’ve settled the issues raised in the introduction.
You might also discuss the more general consequences of the argument, outline what the paper offers to future students of the topic, and suggest any questions the paper’s argument raises but cannot or does not try to answer.
You should not :
There are four main considerations when it comes to the second draft.
The goal during the revision and proofreading process is to ensure you have completed all the necessary tasks and that the paper is as well-articulated as possible. You can speed up the proofreading process by using the AI proofreader .
Check the content of each paragraph, making sure that:
Next, think about sentence structure , grammatical errors, and formatting . Check that you have correctly used transition words and phrases to show the connections between your ideas. Look for typos, cut unnecessary words, and check for consistency in aspects such as heading formatting and spellings .
Finally, you need to make sure your paper is correctly formatted according to the rules of the citation style you are using. For example, you might need to include an MLA heading or create an APA title page .
Scribbr’s professional editors can help with the revision process with our award-winning proofreading services.
Discover our paper editing service
I have followed all instructions in the assignment sheet.
My introduction presents my topic in an engaging way and provides necessary background information.
My introduction presents a clear, focused research problem and/or thesis statement .
My paper is logically organized using paragraphs and (if relevant) section headings .
Each paragraph is clearly focused on one central idea, expressed in a clear topic sentence .
Each paragraph is relevant to my research problem or thesis statement.
I have used appropriate transitions to clarify the connections between sections, paragraphs, and sentences.
My conclusion provides a concise answer to the research question or emphasizes how the thesis has been supported.
My conclusion shows how my research has contributed to knowledge or understanding of my topic.
My conclusion does not present any new points or information essential to my argument.
I have provided an in-text citation every time I refer to ideas or information from a source.
I have included a reference list at the end of my paper, consistently formatted according to a specific citation style .
I have thoroughly revised my paper and addressed any feedback from my professor or supervisor.
I have followed all formatting guidelines (page numbers, headers, spacing, etc.).
You've written a great paper. Make sure it's perfect with the help of a Scribbr editor!
Open Google Slides Download PowerPoint
Other students also liked.
✔ Free APA citation check included ✔ Unlimited document corrections ✔ Specialized in correcting academic texts
University information technology (uit), main navigation, formatting requirements: preliminary pages.
Statement of thesis/dissertation approval, dedication, frontispiece, and epigraph, table of contents and list of figures/tables, acknowledgements.
Preliminary pages are, in order, the title page; copyright page; statement of thesis/dissertation approval; abstract; dedication (optional); frontispiece (optional); epigraph (optional); table of contents; lists of tables, figures, symbols, and abbreviations (necessary only in certain situations); and acknowledgments (optional). Table 2.1 lists all the possible preliminary sections in order and if they are required or not.
The preliminary pages are counted in sequence (except the copyright page, which is neither counted nor numbered). Any page with a main heading on it (title page, abstract, table of contents, etc.) is counted, but no page number is typed on the page. Second pages to the abstract, table of contents, lists, and acknowledgments are numbered with lower case Roman numerals centered within the thesis margins and .5” from the bottom of the page. See the preliminary pages in this handbook for an example.
Order of preliminary pages, indicating which are mandatory and where page numbers should be included.
Page | Required | Counted | Visible Page Number |
---|---|---|---|
Title Page | Mandatory | Yes | No |
Copyright Page | Mandatory | No | |
Statement of Thesis/Dissertation Approval | Mandatory | Yes | No |
Abstract | Mandatory | Yes | First page no, additional pages yes |
Dedication | Optional | Yes | No |
Frontispiece | Optional | Yes | No |
Epigraph | Optional | Yes | No |
Table of Contents | Mandatory | Yes | First page no, additional pages yes |
Lists of Tables, Figures, Symbols, or Abbreviations | Mandatory if between 5–25 | Yes | First page no, additional pages yes |
Acknowledgments | Optional | Yes | First page no, additional pages yes |
Preface | Optional | Yes | First page no, additional pages yes |
Note : Page numbers in the preliminary pages appear centered on the bottom of the page in lower case Roman numerals. This differs from page numbers in the text, which appear on the top right of the page and use Arabic numerals.
SEE Sample Preliminary Pages
The title page is page i (Roman numeral) of the manuscript (page number not shown).
The title of the thesis or dissertation is typed in all capital letters. The title should be placed in the same size and style of font as that used for major headings throughout the manuscript. If longer than 4 1/2 inches, the title should be double spaced and arranged so that it appears balanced on the page. The title should be a concise yet comprehensive description of the contents for cataloging and data retrieval purposes. Initials, abbreviations, acronyms, numerals, formulas, super/subscripts, and symbols should be used in the title with careful consideration of clarity and maximizing search results for future readers. Consult the manuscript editors if in doubt.
The word “by” follows the title. The full legal name of the author as it appears in CIS follows after a double space. The name is not typed in all capital letters. These two lines of text are centered between the title and the statement described in the following paragraph.
The statement “A thesis submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of” appears single spaced in the middle of the title page (see Figure 2.1). For doctoral candidates, the phrasing reads “A dissertation submitted. . . ”
The appropriate degree follows the statement. The space between the statement and the degree should be the same size that is between the author’s name and the statement. In the event the name of the degree differs from the name of the department, e.g., Master of Science in Environmental Humanities, the words “Master of Science” are placed below the statement, followed by “in” and then the degree program; the lines of the degree name and program are double spaced (see Figure 2.2). Thus, a student receiving a doctorate in history need use only the words “Doctor of Philosophy.” A student receiving a doctorate in Geophysics must put “Doctor of Philosophy in Geophysics.”
Below the degree field, the full name of the department is listed on the title page. “The University of Utah,” is listed a double space below the department name.
The date appears on the title page a double space below “The University of Utah.” Only the month and year appear, with no punctuation separating them. The month indicates the last month in the semester the degree is granted: fall semester, December; spring semester, May; summer semester, August.
Again, the spaces below the title, the full legal name, the statement, and the degree should be of equal size.
The second page is the copyright page, which is uncounted and unnumbered. A copyright notice appears in every copy of the thesis or dissertation. The notice, as illustrated in Figure 2.3, is centered within the side margins and the top and bottom margins of the page.
Copyright © Student’s Full Legal Name 2022
All Rights Reserved
There is a double space between the two lines.
The statement of thesis/dissertation approval is page ii (Roman numeral) of the manuscript (page number not shown). This statement is prepared as shown in Figures 2.4 (for master’s students) and 2.5 (for doctoral students).
The statement of thesis/dissertation approval signifies that the thesis or dissertation has been approved by the committee chair and a majority of the members of the committee and by the department chair and the dean of The Graduate School. The names of any committee members who did not approve or digitally sign the forms for the thesis or dissertation are not dated. The dates entered should match the date when you received notification that the committee member electronically signed the form.
The full name of the student, as it appears on the title page and copyright page, must be used.
As with the digital signature forms, full legal names of committee members must be listed. The full legal names of committee members and department chair or dean can be found on your CIS page under the Committee tab. Neither degrees nor titles should be listed with the names of faculty members. No signatures are required.
The abstract is page iii, unnumbered; if there is a second page, it is page iv, and a number appears on the page. The abstract is a concise, carefully composed summary of the contents of the thesis or dissertation. In the abstract, the author defines the problem, describes the research method or design, and reports the results and conclusions. No diagrams, illustrations, subheadings, or citations appear in the abstract. The abstract is limited to 350 words (approximately 1.5 double-spaced pages). A copy of the abstract of all doctoral candidates is published in Dissertation Abstracts International. The word ABSTRACT is placed 2 inches from the top of the page in all capital letters. Following a heading space, the abstract text begins, with the first line indented the same size space as for the paragraphs in the remainder of the manuscript. The text of the abstract must be double spaced.
If a manuscript is written in a foreign language, the abstract is in the same language, but an English version (or translation) of the abstract must precede the foreign language abstract. The two abstracts are listed as one in the table of contents. The first page of each version is unnumbered but counted. If there is a second page to each version of the abstract, the page number (lower-case Roman numeral) is centered between the left and right margins and between the bottom of the page and the top of the bottom margin.
The dedication is an optional entry; enumeration continues in sequence, but no page number appears on the page. It follows the abstract and precedes the table of contents. Often only one or two lines, it is centered within the top and bottom margins of the page and within the thesis margins. It is not labeled “Dedication” and is not listed in the table of contents.
These are infrequently used entries. The frontispiece is an illustration that alerts the reader to the major theme of the thesis or dissertation. An epigraph is a quotation of unusual aptness and relevance.
The table of contents follows the abstract (or dedication if one is used). The word CONTENTS (or TABLE OF CONTENTS) is placed 2 inches from the top of the page in all capital letters. Following a heading space, the table of contents begins. The table of contents, essentially an outline of the manuscript, lists the preliminary pages beginning with the abstract (page iii). It does not list a frontispiece, dedication, or epigraph if these are used, nor is the table of contents listed in the table of contents; these pages are, however, counted. The list of figures and list of tables, if used, are included (see the Table of Contents in this handbook for a sample using numbered chapters; see Figures 2.6, 2.7, and 2.8 for additional options).
All chapters or main sections and all first-level subheadings of the manuscript are listed in the table of contents. No lower subheadings levels are to appear in the table of contents. Beginning page numbers of each chapter or section listed are lined up with each listing by a row of evenly spaced, aligned period leaders. The numbers, titles, and subheadings of chapters or sections used in the table of contents must agree exactly in wording and capitalization with the way they appear on the actual page.
The table of contents reflects the relationship of the chapters and subheadings. Chapter titles appear in all capital letters, as do titles of appendices. First-level subheadings can be headline style or sentence style in capitalization. Subheadings are neither underlined nor italicized in the table of contents. If the table of contents continues to a second page, it begins 1 inch from the top of the page, and it is not labeled “Table of Contents Continued.” Main headings are followed by a double space in the table of contents; all subheadings are single spaced. The words “Chapters” and “Appendices” are used as referents only, printed above the list of entries. The word “Chapter” or “Appendix” is not repeated with each entry.
The enumeration continues in sequence; no number appears on pages with main headings (those in all caps). A list of tables, a list of figures, a list of symbols, a list of abbreviations, or a glossary may be used. All lists follow the table of contents. The title is placed 2 inches from the top edge of the page in all capital letters: LIST OF TABLES. Following a heading space, the list begins. A list of tables or a list of figures is required if there are 5 to 25 entries. Lists with fewer than 5 entries or more than 25 are not included. It is not permissible to combine a list of tables and figures. The word “Table” or “Figure” is not repeated with each entry.
As noted for entries in the table of contents, the listing of tables and figures must agree exactly in wording, capitalization, and punctuation with the table title or figure caption. (An exception to this rule occurs if the table title appears in all capital letters on the table itself; table titles in the list of tables are not typed in all capital letters.) Capitalization styles may not be mixed. In the case of long titles or captions, the first sentence must convey the essential description of the item. The first sentence alone then is used in the list. Long captions may not be summarized.
The table or figure number begins at the left margin and is followed by the title or caption. The page on which each table or figure appears is at the right margin. As in the table of contents, the page numbers are lined up with each entry by a row of evenly spaced, aligned periods (period leaders). If a table or figure occupies more than one page, only the initial page number is listed. If the title or caption of a table or figure appears on a part-title page preceding the table or figure, the page number in the list refers to the number of the part-title page.
If a list continues to a second page, the second page of text begins 1 inch from the top of the page. The second page is not labeled “List of Tables Continued” or “List of Figures Continued.” Individual entries are single-spaced with a double space between each entry.
A list of symbols and abbreviations or a glossary does not replace defining terms, symbols, or abbreviations upon their first occurrence in the text. When introducing terms, always introduce terms upon their first usage in the document.
The enumeration continues in sequence; no number appears on the first page. Acknowledgments are optional. If a preface is used, the acknowledgments are added to the end of the preface without a separate heading. The word ACKNOWLEDGMENTS is placed 2 inches from the top of the page in all capital letters. Following a heading space, the acknowledgments begin. The text of the acknowledgments must be double spaced. In the acknowledgments, students may wish to recognize special assistance from committee members, friends, or family members who may have helped in the research, writing, or technical aspects of the thesis or dissertation. Research funding, grants, and/or permission to reprint copyrighted materials should be acknowledged. Individuals employed to prepare the manuscript are not acknowledged.
The enumeration continues in sequence; no number appears on the first page. This is an optional entry. The word PREFACE is placed 2 inches from the top of the page in all capital letters. Following a heading space, the preface begins. The text of the preface must be double spaced. A preface includes the reasons for undertaking the study, the methods and design of the researcher, and acknowledgments. Background data and historical or other information essential to the reader’s understanding of the subject are placed in the text as an introduction, not in the preface. Theses and dissertations generally do not contain a foreword (i.e., a statement about the work by someone other than the author).
Thesis / dissertation formatting manual (2024).
The Preliminary Pages require very specific wording, spacing, and layout. Templates and sample pages are provided for your reference.
Only the pages listed below may be included as part of the Preliminary Pages section, and they must appear in this order. No other pages are permitted. All pages are required except the Dedication Page. Lists of Symbols, Tables, Figures, and Illustrations are only required if applicable to the content of your manuscript.
Note : A Signature Page is NOT a valid part of your manuscript and is not included in the submission of your thesis or dissertation. Committee signatures are now included on the “Ph.D. Form II/Signature Page” or the “Master’s Thesis/Signature Page” that you submit to the Graduate Division.
Preliminary Pages are numbered with lowercase Roman numerals.
Off-campus? Please use the Software VPN and choose the group UCIFull to access licensed content. For more information, please Click here
Software VPN is not available for guests, so they may not have access to some content when connecting from off-campus.
New design of an electronic power system for the cosmic x-ray background nanosatellite-3, related papers.
Showing 1 through 3 of 0 Related Papers
Purdue Online Writing Lab Purdue OWL® College of Liberal Arts
This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.
Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.
Once the design concepts have been developed and a final concept has been selected, the next stage in the design process is to develop the preliminary design of each of the system components. The key elements of most preliminary designs include an outline of the following items: the design’s systems, its basic requirements, and the high-level design features.
For our UAV example, we would start by creating a flowchart (or similar schematic) of the various systems, subsystems, and components of the UAV. For example, let’s say that we want to create a schematic of the flight system. Assuming we choose the quadcopter concept design, our top-level “block” in the flowchart would say “flight system.” Then, we would subdivide this system into its constituent subsystems, namely, each of the four rotor assemblies. These rotor assemblies consist of individual components, including the rotor blades, motors, wiring, and possibly the electronic speed controllers (ESCs). The motors and ESCs each have dozens of internal components, and the level of representation of these components is dependent on the requirements that must be levied on the system.
For example, if the motors are designed in-house, it may make sense to further subdivide the motor into flowchart blocks that highlight its major components, as their design requirements may be tighter due to the ability to control each minute specification. However, if the motor is sourced from an external supplier, then the level of subdivision may be more coarse—i.e., limited to the options that can be specified when ordering from the supplier. The figure below shows an example of a preliminary design flowchart for our quadcopter’s flight system.
Quadcopter preliminary design flowchart
After creating flowcharts for each UAV system, the next step is to clearly define the system, subsystem, and component requirements. These requirements are often determined after consulting with the end users and developing mission use-cases. For example, let’s say that the farmers using the UAV want to be able to conduct at least 500-acre aerial sweeps in a single charge. In this case, the quadcopter must be able to aerodynamically support the weight of its components plus the imaging equipment while navigating the field area. It must also be capable of supplying adequate power to the imaging equipment and flight systems while accounting for the extra power demanded by anomalous factors such as wind gusts or changes in altitude to accommodate low or high-level imaging.
The design features of each system are usually defined quantitatively, so high-level aerodynamic, structural, and electrical analyses should be carried out to obtain approximate numbers for each of the systems and subsystems. The minute details of each component and system will be defined later in the detailed design phase. Once the features are defined, they are analyzed to ensure that they meet the pre-specified design requirements. The text below shows a sample of what the requirements and design features of the quadcopter flight system might look like:
Requirements: The quadcopter’s flight system must be capable of supporting 32 kg throughout the entire flight envelope. Nominal operating altitude will top out at 30 meters above ground level. The quadcopter must be capable of at least 10 m/s horizontal speed and at least 5 m/s vertical speed while overcoming vertical wind gusts of up to 2 m/s…
Design features: The quadcopter rotors will consist of three blades with airfoils characterized by a high L/D ratio. The rotors will be fabricated out of glass fiber composite material. The motors will be brushless and powered by a Lithium-ion battery…
Note that this stage of the design process becomes an increasingly iterative process. This means that once a system’s preliminary design is completed, it should be reviewed and modified in order to generate a new design. This looped process saves time and resources by considering the effects of a particular system architecture and incorporating changes at the early stages of the design. Therefore, the preliminary design documentation may also include simulation and requirement verification reports that highlight the necessary design changes prior to developing the detailed designs of each system and component.
For example, let’s say that the quadcopter rotors are initially designed to have three blades. However, a preliminary aerodynamic analysis of the rotors suggests that at least four blades will be necessary to generate enough lift to overcome the stipulated minimum wind gust requirement of 2 m/s. The best course of action is therefore to create a report that includes the quantitative results of this mission architecture simulation and a list of the requirements that were both met and not met. Finally, the necessary architecture/design changes should be clearly enumerated.
To summarize, the preliminary design document consists of the following elements:
Cite this chapter.
4272 Accesses
The Preliminary Design Review (PDR) session helps you to make sure that the robustness diagrams, the domain model, and the use case text all match each other. This review is the “gateway” between the preliminary design and detailed design stages, for each package of use cases.
This is a preview of subscription content, log in via an institution to check access.
Tax calculation will be finalised at checkout
Purchases are for personal use only
Institutional subscriptions
Unable to display preview. Download preview PDF.
Doug Rosenberg, Matt Stephens, and Mark Collins-Cope, Agile Development with ICONIX Process (Berkeley, CA: Apress, 2005).
Google Scholar
These steps are described in more detail in Chapter 6 of Applying Use Case Driven Object Modeling with UML by Doug Rosenberg and Kendall Scott (Addison-Wesley, 2001).
Download references
Reprints and permissions
© 2007 Doug Rosenberg and Matt Stephens
(2007). Preliminary Design Review. In: Use Case Driven Object Modeling with UML. Apress. https://doi.org/10.1007/978-1-4302-0369-8_6
DOI : https://doi.org/10.1007/978-1-4302-0369-8_6
Publisher Name : Apress
Print ISBN : 978-1-59059-774-3
Online ISBN : 978-1-4302-0369-8
eBook Packages : Professional and Applied Computing Professional and Applied Computing (R0) Apress Access Books
Anyone you share the following link with will be able to read this content:
Sorry, a shareable link is not currently available for this article.
Provided by the Springer Nature SharedIt content-sharing initiative
Policies and ethics
Lauren griffin.
Developing a research project involves a lot of planning and preparation. A preliminary research design describes the specifics of a planned project and should address the purpose of the proposed study, as well as details on how the study will be conducted.
A preliminary research design must introduce the proposed study by stating what the study will be investigating, the hypothesis, and the significance of the subject. By completing a literature review, summarizing the main findings of these studies, and relating them to the current project, the researcher can explain how their study adds to the existing field of knowledge.
Preliminary research design must provide an overview of the study's methodology. This should include an explanation of what variables will be looked at and how they will be measured, where the study will take place, what tools or techniques will be used, and other information regarding how the study will be conducted.
The researcher must propose a specific time line for her project in her preliminary research design, in which different stages of the study are allotted different amounts of time. Research designs also address the project's budget. It's best to identify specific expenditures and give an accurate view of precisely how money will be spent.
Lauren Griffin began writing professionally in 2010. Her articles appear on various websites, specializing in academics, food and other lifestyle topics. Griffin attended Columbia University and holds a Bachelor of Arts in psychology.
Regardless of how old we are, we never stop learning. Classroom is the educational resource for people of all ages. Whether you’re studying times tables or applying to college, Classroom has the answers.
© 2020 Leaf Group Ltd. / Leaf Group Media, All Rights Reserved. Based on the Word Net lexical database for the English Language. See disclaimer .
Car design is a complex task because of how highly integrated system of systems it is. Fine?designed car models take years of design and optimization and are usually done by specialty teams who are dedicated to each sub-system. This thesis delves into designing a simplified electric race car from scratch with focus on the performance envelope of it. First, a 3D CAD model was done using SolidWorks. That section deals with spatial engineering and strategic placement of major car components for best performance. Having most of the parts in place gives a rough estimate of CoG (Center of Gravity) location, which is needed for vehicle dynamics analysis, which are discussed later in the report. The target for this project car is to have innovative aerodynamics features which might not have been used before because of bulky internal combustion engines restricting available space. One of them is an airfoil-like fascia which makes the center part of the car act as a one big wing. That is believed to give a significant reduction in drag loads on the car. The approach for aerodynamics design and analysis started with a model representing the car’s OML (Outer Mold line) which was simulated separately using Siemens StarCCM+. After understanding the car’s body aero behavior, a rear wing was added to provide extra rear downforce for better handling and stability. The rear wing design was explained in detail. Unfortunately, due to time restrictions as well as software access issues, the aerodynamic analysis of the full car with rear wing is left for future work. After having an estimate about aero loads acting on the car, vehicle dynamics analysis could start. The first subject studied in vehicle dynamics was front-view suspension geometry analysis. Taking the available packaging and geometry into consideration, a 2D model was done in SolidWorks to optimize camber gain. This analysis gave the motion ratio of the front and rear pushrod suspension system which was needed to analyze the performance of the one-eighth car model, ½ car pitch model, and ½ car roll model. These models gave insights into the decision-making process for spring and damping rates to reach a good balance between performance and comfort. This project acts as a hub for further development and studies related to car design.
Additional committee member 2, additional committee member 3, usage metrics.
Despite the non-contact underwater explosion phenomena (UNDEX) have been studied for decades and several numerical methods have been proposed in literature, its effects on military structures, especially composite ones, are even nowadays matter of research. In early design phases, it is not always possible to verify the shock resistance of hull structures modelling the whole phenomenon, in which fluid, gas and solid properties must be properly set in a fully coupled fluid-structure interaction (FSI) numerical model. These ones are extremely complex to set, computationally demanding and certainly not suitable for everyday design practice. In this paper, a simplified finite element (FE) model, easy to use in an early design phase, is proposed. Both, the structure and the fluid are simulated. In this approximation, the fluid behaviour is simplified, using special finite elements, available in a commercial software environment. This choice reduces the computational time and numerical efforts avoiding the problem of combining computational fluid dynamics (CFD) and FE domains and equations in a fully coupled fluid-structure interaction model. A typical parallel body block of a minesweeper is modelled, using two-dimensional multi-layered shell elements to properly account for the composite materials behaviour. For the fluid instead, three dimensional volumetric elements, directly coupled to the structural elements, are placed. In addition, the same calculation is performed, modelling separately fluid in the CFD environment and structures in the finite element one. Thus, realizing a fully coupled fluid-structure interaction model. The results obtained by applying both numerical models are compared with the structural response measured on board of a composite ship during a full-scale shock test. The simplified proposed procedure provides results in satisfactory agreement with experiments, allowing the validation of the model. Approximations are discussed and differences with the real phenomenon and fully coupled CFD+FE method are shown, providing a better understanding of the phenomena. Eventually, the modelling strategy has been considered a valuable and cost-effective tool for the concept and preliminary design of composite structures subject to underwater explosions.
IMAGES
VIDEO
COMMENTS
The length and complexity of describing the research design in your paper can vary considerably, ... The focus is on gaining insights and familiarity for later investigation or undertaken when research problems are in a preliminary stage of investigation. Exploratory designs are often used to establish an understanding of how best to proceed in ...
Preliminary research gives you background information on your topic, answering questions such as who, what, when and where. ... Background information will enrich your research paper but should not bog it down in trivia. For example, if you were doing a paper on Hildegaard of Bingen, you should know that she was born into a noble family in ...
Preliminary Considerations ... research designs); and specific research methods of data collection, analysis, and interpretation. The selection of a research approach is also based on the nature of the research problem or issue being addressed, the researcherspersonal experiences, and the audiences for the study. Thus, in this book, '
An Appr oach to Pr eliminary Design and Analysis. Craig Collier. , Phil Yarrington. , Mark Pickenheim. , and Brett Bednarcyk. [email protected]. Collier Research Corp., Hampton, VA ...
Explore the latest full-text research PDFs, articles, conference papers, preprints and more on PRELIMINARY DESIGN. Find methods information, sources, references or conduct a literature review on ...
Step 4: Create a research design. The research design is a practical framework for answering your research questions. It involves making decisions about the type of data you need, the methods you'll use to collect and analyze it, and the location and timescale of your research. There are often many possible paths you can take to answering ...
Preliminary Design Review Guidelines . ME481 Spring 2020 . Purpose "A design review is a retrospective study of the design up to that point in time. It provides a systematic method for identifying problems with the design, aids in determining possible courses of action, and initiates action to correct the problem areas." 1. Design reviews ...
A decimal outline is similar in format to the alphanumeric outline, but with a different numbering system: 1, 1.1, 1.2, etc. Text is written as short notes rather than full sentences. Example: 1 Body paragraph one. 1.1 First point. 1.1.1 Sub-point of first point. 1.1.2 Sub-point of first point.
Abstract. A designer often has to deal with complex and ill-structured situations during specification synthesis and preliminary engineering design. To assist in the development of computer-aided design systems, it is desirable to capture the designers decision-making process during these design states. The research presented in this paper is ...
The research presented in this paper is towards this direction. Based on the conceptual understanding of the process, three postulates are presented. ... at the preliminary design, although the remaining objectives do have a weak influence on the preliminary design; are used to develop a compensatory and a non-compensatory model of the decision ...
The Preliminary System Design process will be carried out much like the Engineering Alternative Analysis process. In that process, each Critical Component was selected, but before the selection was finalized, the entire list of alternatives had to be considered from a system-level point of view to ensure compatibility.
1. An Overview. Broadly, preclinical research can be classified into two distinct categories depending on the aim and purpose of the experiment, namely, "hypothesis generating" (exploratory) and "hypothesis testing" (confirmatory) research (Fig. 1).Hypothesis generating studies are often scientifically-informed, curiosity and intuition-driven explorations which may generate testable ...
The preliminary outline can serve as your road map for research. How do you create a preliminary outline? First, realize that all research papers will start with an introduction and end with a conclusion. In between, there are usually three to five points that must be covered in order to answer the question sufficiently.
Choose a research paper topic. Conduct preliminary research. Develop a thesis statement. Create a research paper outline. Write a first draft of the research paper. Write the introduction. Write a compelling body of text. Write the conclusion. The second draft.
In the abstract, the author defines the problem, describes the research method or design, and reports the results and conclusions. No diagrams, illustrations, subheadings, or citations appear in the abstract. ... The table of contents, essentially an outline of the manuscript, lists the preliminary pages beginning with the abstract (page iii ...
The culmination of the Preliminary Design process is an event called the Preliminary Design Review (PDR). At this event, the design team presents their solution to the Problem Statement for the other Stakeholders' approval. At this point in the Design Life-Cycle, the Stakeholders have not risked any significant resources (money).
5.1 Appearance. The appearance of a building involves a range of facts, features and elements, which together make up the design first on paper and later in reality. The description of a design includes general aspects like the shape, the relationship between different components as well as characteristic elements like the roof and the wall ...
Final detailed design. Mark T. MacLean-Blevins, in Designing Successful Products with Plastics, 2018 Abstract. The preliminary design phase of a product or part manufactured from plastics should conclude with a comprehensive design review. Once the project is approved to move to production implementation, the design team enters this final detailed design phase of the project, which is the ...
The Preliminary Pages require very specific wording, spacing, and layout. Templates and sample pages are provided for your reference. Only the pages listed below may be included as part of the Preliminary Pages section, and they must appear in this order. No other pages are permitted. All pages are required except the Dedication Page.
Semantic Scholar extracted view of "Preliminary Design Review (PDR)" by K. Pries et al. ... Semantic Scholar's Logo. Search 217,797,147 papers from all fields of science. Search. Sign In Create Free Account. DOI: 10.1201/9781420072068.AXG; ... AI-powered research tool for scientific literature, based at the Allen Institute for AI. Learn More.
Stage 2: Preliminary Design. Once the design concepts have been developed and a final concept has been selected, the next stage in the design process is to develop the preliminary design of each of the system components. The key elements of most preliminary designs include an outline of the following items: the design's systems, its basic ...
The Preliminary Design Review (PDR) session helps you to make sure that the robustness diagrams, the domain model, and the use case text all match each other. This review is the "gateway" between the preliminary design and detailed design stages, for each package of use cases. Download to read the full chapter text.
Developing a research project involves a lot of planning and preparation. A preliminary research design describes the specifics of a planned project and should address the purpose of the proposed study, as well as details on how the study will be conducted. > ... How to Write a Research Paper Proposal .
Car design is a complex task because of how highly integrated system of systems it is. Fine?designed car models take years of design and optimization and are usually done by specialty teams who are dedicated to each sub-system. This thesis delves into designing a simplified electric race car from scratch with focus on the performance envelope of it. First, a 3D CAD model was done using ...
Despite the non-contact underwater explosion phenomena (UNDEX) have been studied for decades and several numerical methods have been proposed in literature, its effects on military structures, especially composite ones, are even nowadays matter of research. In early design phases, it is not always possible to verify the shock resistance of hull structures modelling the whole phenomenon, in ...
Microsoft Forms is a web-based application that allows you to: Create and share online surveys, quizzes, polls, and forms. Collect feedback, measure satisfaction, test knowledge, and more. Easily design your forms with various question types, themes, and branching logic. Analyze your results with built-in charts and reports, or export them to ...