---
# System prepended metadata

title: Model-Based Approach to the Requirements Analysis for a Conceptual Aircraft Sizing and Synthesis Problem

---

# Model-Based Approach to the Requirements Analysis for a Conceptual Aircraft Sizing and Synthesis Problem
**Karagoz, Esma, Kevin A. Reilley, and Dimitri N. Mavris.， The AIAA Scitech 2019 Forum. 2019.**

State the objective of this research including motivation, original contributions, methods and reason for choosing the specific methods.

## Keyword Explanation (will be moved to Terminology)
**Top-level design of aircraft**
<font color="#f00">**Did you copy it from the paper? Anyway, This is not the explanation of TLAR. Please rewrite it or change the title.**</font>
Aircraft design is a complex large-scale system engineering involving multi-disciplinary and multi-technical fields. Aircraft design work is generally divided into three stages: conceptual design, preliminary design, and detailed design. The first two stages are also called overall design. The top-level/detailed design technology of aircraft is an important content of the comprehensive technology adopted by modern countries to develop advanced aerospace vehicle systems, and it is also the development trend of future aircraft design and research. The top level is a higher level than the conceptual design, which is to study the aerospace vehicle system to be designed from the perspective of a higher level and a large system in the initial stage of the design, aiming at the situation that the amount of information in the early stage of the design is less. Top-level design is the initial planning phase of the design of complex systems such as aerospace vehicle systems. It uses the principles and methods of systems engineering to conceive system solutions and determine system technical requirements under given mission objectives and constraints, and meet schedule requirements at an affordable cost. In general, the top-level design of aircraft is to consider and study relevant issues from the perspective of top-level and large-scale system, starting from user requirements/needs, in the case of less information in the early stage of design, and to evaluate the feasibility of aircraft design in the early stage of design. The key content in the research and design is studied and weighed, and the **top-level design is the initial stage beyond the conceptual design stage.
![](https://i.imgur.com/oYGxl4C.png)

**Thrust-to-weight ratio**
Thrust-to-weight ratio is a dimensionless ratio of thrust to weight of a rocket, jet engine, propeller engine, or a vehicle propelled by such an engine that is an indicator of the performance of the engine or vehicle. The instantaneous thrust-to-weight ratio of a vehicle varies continually during operation due to progressive consumption of fuel or propellant and in some cases a gravity gradient. The thrust-to-weight ratio based on initial thrust and weight is often published and used as a figure of merit for quantitative comparison of a vehicle's initial performance.**The thrust-to-weight ratio is calculated by dividing the thrust (in SI units – in newtons) by the weight (in newtons) of the engine or vehicle.**

**Wing loading**
**DJ Kim - Change the title to wing loading. I think you need to differentiate weight and mass. Please describe the difference between weight and mass.**
Wing loading is a measurement that relates the mass of an aircraft or bird to the total wing area. The relationship between wing area and body weight is given in kilograms per square metre (or grams per square centimetre). To calculate wing loading, divide the mass of the bird or plane by the total area of the upper surface of its wings: wing loading = body mass (kg)/wing area (m2).

## 1) Research Motivation
The document-centric process of conventional system engineering is a major drawback <font color="#f00">**of what?**</font>. The primary means of communicating requirements, system information, and other design-related artifacts is through various types of controlled documentation. ~~Design reviews assess design objects and produce new documentation so that the next design phase can begin.~~<font color="#f00"> </font> ~~As a result,~~ <font color="#f00"> **where is the causal relationship that made you use "as a result"?**</font> the author ~~thinks that~~ <font color="#f00"> **Please do not use "the author thinks that". Do you know whether the author thinks like that or not? Eventhough you can guess that the author thinks in some particular ways, you should not use the verb "think" in the research summary. Use "proposed", "suggested", "developed", and so on...**</font> the Model-Based Systems Engineering (MBSE) approach can be more effective by using models rather than documents. Models are mostly used in MBSE to organize requirements and system data. In order to assess model-based design artifacts and enable decisions to be implemented directly into the system model, these models may also be the subject of electronic design reviews. In addition, MBSE promotes the use of models and allows stakeholders to participate in the system acquisition. ~~At the same time, MBSE enables stakeholders to be involved in the system acquisition~~ <font color="#f00"> **you are repeating the same thing here**</font>and encourages the use of models to improve the communication between them to be able to capture the design needs in the early phases of design.


**DJ Kim - (The following is my edition. Read and think about what makes them different. I tried to keep your sentences as much as possible.) The primary means of communicating requirements, system information, and other design-related artifacts <font color="#f00">in an aircraft design process has been</font> through various types of controlled documentation. <font color="#f00">However, </font>the document-centric process has been a major <font color="#f00">bottleneck of design and development of an aircraft. To address this issue, </font> the author proposed the Model-Based Systems Engineering (MBSE) approach for organizing requirements and system data. MBSE enables assessing model-based design artifacts and making decisions to be implemented directly into the system model. In addition, MBSE allows stakeholders to be able to capture the design needs in the early phases of design.**

```
Lijing - I think your arrangement improved narrative logic. The motivation should start from the limitation/research status of previous research and explain the improvement direction and reasons for the current research, so as to fully describe the motivation of a paper. My previous narrative mentioned the problem and their approach, but failed to connect the two.**
```

## 2) Research Details and Methods
Their research revolves around the design problem, including constraint analysis, mission analysis and a sizing of the aircraft by weight, which is also driven by top-level requirements and certification regulations. **DJ Kim - What does this "revolves around the design problem" mean? Do you want to say "evolve" or "vary"?** 
```
Yes,I mean evolve
```
During the constraint analysis, certain performance and design requirements become <font color="#f00"> **Do you want to say "are expressed as"**</font> mathematical relations between the minimum sea-level-thrust-to-take-off-weight ratio (TSL/WTO) and take-off-weight-to wing area ratio. The outcome is the constraint plot, which depicts the feasible design region. Then, in the mission analysis, the fuel consumed during each mission segment is calculated, using either aircraft performance equations or ~~previous experience~~ <font color="#f00">**empirical equations derived from previous experience**</font>. In the sizing process, the takeoff gross weight is calculated using the weight fractions coming from the mission analysis, payload and crew weights, specified in the requirements, and empty weight which is obtained from historical trends.

A basic system engineering(SE) <font color="#f00">**SE was not stated anywhere in this paragraph. I told you about this abbreviation issue in the last paper reading practice. I hope I don't need to repeat it again. I know it stands for system engineering, and I am not asking you to do this for me. Remember you are practicing academic reading/writing here.**</font> methodology is applied in a model-centric approach for this design problem. <font color="#f00">**Connection to the next sentence is missing or weak. What are this basic SE methodology and model-centric approach? The readers expect one of basic SE methodologies and/or model-centric approaches from next sentences**</font>

```
Many engineering specialties, particularly aeronautical engineering, use Systems Engineering (SE) techniques and approaches extensively. In order to create system design requirements, the SE discipline primarily involves assessing and eliciting top-level program objectives and needs as well as the necessary functionality of the system. These requirements are then checked against the analyses carried out in the design synthesis phase. At the same time, model centric design approach making decisions to be implemented directly into the system model, which allows stakeholders to be able to capture the design needs in the early phases of design. A basic system engineering(SE) methodology is applied in a model-centric approach for this design problem.
```
<font color="#f00"> **DJ Kim - correct "At the same time, model centric design approach making decisions to be implemented directly into the system model, which allows stakeholders to be able to capture the design needs in the early phases of design."**</font>
    
    
Systems Modeling Language(SysML) **DJ Kim - Again, SysML was not stated anywhere in this paragraph** is used to incorporate text-based requirements into the system model. The MBSE-enabled process, which is more practical for detecting correlations between key crucial design parameters and top-level system objectives and needs, is favored to the traditional process during their research. Additionally, <font color="#f00">**Additionally sounds strange here. Think about it in this way. What you wrote it "MBSE is favored. Additionally, MBSE can do something." Do you understand what makes it stange?**</font>it ~~makes it possible to create~~ <font color="#f00">**I think "enables creating" would be better than "it makes it possible~" because repeating pronoun "it" makes the readers hard to connect these "it" to actual noun, clause, or phrase that two "it" refer.**</font> a requirements-driven system description <font color="#f00">**Is this really "description"**</font> so that the implications of design changes and requirement propagation can be seen more clearly. As a result, the system engineers can explore more design possibilities during the early design stages since thorough evaluation of the options in a timely way for a challenging design challenge results in a significant decrease in cycle time and effort. **DJ Kim - I think this sentence is grammatically wrong. Check "for a challenging design challenge results in a significant decrease in cycle time and effort." and rewrite it.** By reducing manual consistency checking, improved automation and standardization of design procedures in MBSE can also hasten the construction of aircraft.
```
Lijing - Rewriting
As a result, system engineers can explore more design possibilities at an early design stage, as timely and comprehensive evaluation of options for challenging designs can significantly reduce overall cycle time and effort.
```

## 3) Original Contributions
In this study, the author developed a Model-Based Systems Engineering (MBSE) to enable process for requirements analysis for the design problem. Their research mainly focuses on the definition of initial system requirements, functional analysis and allocation, and the requirements loop in the SE process. The requirements decomposition and allocation procedure uses top-level program objectives provided by stakeholders, marketing requirements, and certification regulations. Additionally, functional analysis and allocation are done to create the specifications that outline the system's functionality.

<font color="#f00">**DJ Kim-Is this really their original contributions? The way it is written doesn't tell anything about the original contiributions.**</font>
```
Lijing - This study explains the methods to be used to derive the system requirements for a design problem, and also to build the requirement models created in SysML to better comprehend and visualize the design problem relationships.