Definition Of System Requirements Research Articles

Early Design Stage Evaluation of All Electric Aircraft Power Systems Focusing on Long-Term Behavior

In the aircraft industry, there is a shift towards more and all-electric power systems resulting in great research efforts on single components like batteries. At the same time there is an increasing need to investigate and evaluate the long-term behavior of the whole electric power system to ensure safe and sustainable aircraft operation. Focusing on this challenge, the objective of this article is to propose a framework for electric power system assessment in the early design stages. In particular, the focus is on identifying and handling uncertainties regarding failure behavior and degradation, both on the component and system level. The evaluation of different power system topologies is based on the integration of Model-Based Systems Engineering and robust design methods. In this context, another central aspect is the definition of system and component requirements derived from the flight mission profile. SysML diagrams are used to define use cases and possible system topologies. Sensitivity of degradation effects are evaluated using robust design methods. The application of the framework and these methods is illustrated using a short-range aircraft with an all-electric power system. The results highlight the applicability of the framework to cope with the uncertainties that occur in the early design stages and point out fields of further research.

MIGRATING TO ARP4754A: TAILORING OF ARCHITECTURE AND SYSTEMS REQUIREMENTS DEFINITION PROCESSES IN THE ROTORCRAFT INDUSTRY

AbstractRotorcrafts are very complex systems that require a huge systems engineering effort to design, implement and integrate. A successful aircraft design is a matter of good integration between engineering disciplines and suppliers just as much as it is about finding a good technical solution to the customers' expectations. This issue is well understood within the industry and competent authorities. Companies now face the challenge of transitioning from integrating complex systems to make an aircraft (as per ARP4754) to engineering and collating a complex aircraft system as per ARP4754A: in other words, the focus shifted to a more holistic view to the aircraft development, a game changer in all respects. Leonardo Helicopters is tailoring its internal processes to reflect this change and challenge. While the ideal process can be defined today, the transition takes time and a significant change in culture and organization needs to take place. To support the transition, the authors have developed a hybrid approach to the aircraft architecture and system requirements definition process. This new approach leverages existing expertise at a system level to facilitate the integration between systems and the subsequent migration to bridge the gap with the aircraft engineering activities required by the ARP4754A.

Long-baseline multistatic and bistatic SAR products: Application to the RODiO mission

In-Orbit Demonstration (IOD) missions represent flight opportunities to acquire data on spacecraft and space environment and to demonstrate new techniques at system, subsystem, and payload level. Realizing this type of mission means accepting a greater level of risk. However, when very compact and relatively simple platforms like CubeSats are adopted, this becomes admissible since costs can be kept low. Distributed Synthetic Aperture Radar (SAR) is a novel Earth Observation (EO) technique for microwave imaging. It uses multiple cooperating receivers and suitable processing to enable performance and products that exceed those of the single components of the system. RODiO (Radar for earth Observation by synthetic aperture Distributed on a cluster of CubeSats equipped with high-technology micro-propellers for new Operative services) is an IOD of the distributed SAR concept. The mission is based on four, 16 U, CubeSats, that embark a receiving-only X-band SAR instrument able to collect bistatic echoes exploiting a monostatic SAR as an opportunity illuminator, i.e PLATiNO-1 mission. Distributed SAR demonstration is thus pursued in RODiO combining the principles of both multistatic and bistatic SAR. The paper, moving from mission goals, individuates different families of EO products that RODiO can demonstrate, e.g. in the contest of ground motion, digital elevation models, and ship detection. The main result is the definition of the RODiO system requirements for product generation that drive satellites and payload design.

Systems engineering procedure for requirements management of divertor system of tokamak reactors

Systems Engineering allows to address the design of complex systems from the early stage until the end of its lifetime with the aim to realize successful systems. The intrinsic complexity of tokamak design requires to adopt Systems Engineering guidelines to write correctly and efficiently a large set of system requirements. Well-formed requirements would make efficient and consistent the downstream design, integration, and verification of a system. The process of requirements definition, conformed to Guide to System Requirements Definition recommended in fusion field, is far from simple and fast. The requirements definition phase encourages the early identification of issues that can be acted in the life cycle. This paper firstly highlights a new procedure to include requirements of a tokamak component in the requirement management tool of the whole system. This work identifies engineering requirements and constraints and describes their impact on the selection of the design principles of the EU-DEMO divertor system. The new identified procedure is developed using a participative approach involving experts belonging to different working groups.

An approach towards the implementation of a reliable resilience model based on machine learning

Machine Learning tools to enhance systems’ resilience received an increased impetus driven by energy transition, climate change and digitalization, but critical challenges on system requirement definition and reliability of learning processes need to be addressed. This study proposes a systematic framework based on system engineering and focused on the reliability of the learning process of the Hidden Markov Model (HMM) coupled with the Baum-Welsh algorithm. The HMM hidden states may represent the precursors of accidental events, being the states between a regular performance and a failure of a sub-system. The Baum-Welch algorithm, estimating the parameters of the HMM, iteratively updates the estimates of the state transition and observation probabilities. The framework was applied to a real case of LNG bunkering, showing that the system can learn from incomplete data, improve the learning quality given a new set of observations, make predictions about the latent states and enhance system resilience. The novelty of this work lies in ensuring the learning process and contributing to the attainment of an explainable, robust, and interpretable data-driven approach.

Requirements Rationalization and Synthesis Enabled by Model Synchronization

In the international standard for system and software engineering ISO/IEC/IEEE 15288: 2015, the output of the stakeholder needs and the business or mission analysis technical processes are transformed into a technical view of the system by the system requirements definition process. In model-based systems engineering, functional needs can be modeled by use case diagrams. Intended outcomes of system requirements definition include resolution of disagreement about requirements, explicit agreement between stakeholders, and traceability. However, stakeholder needs are often elicited in a siloed manner and may be inconsistent. The lack of mathematically based systematic approaches for requirements definition poses a challenge to model-based transformation of needs into a technical view of the system that achieves agreement between stakeholders. This paper specifies and demonstrates mathematical frameworks for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rationalizing</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">synthesizing</i> functional needs that have been captured through an elicitation process. Benefits of this approach include but are not limited to supporting rigorous identification and resolution of disagreements and facilitating systematic analysis of change impact to achieve stakeholder agreement all with minimal intervention by the system engineers.

Option for evaluation of development of decision support system requirements

The quality of the decision support system (DSS) is influenced by the process of creating this system. An important part of the DSS creation process is occupied by events that discuss issues related to the definition of system requirements. Both representatives of the customer and representatives of the executor take part in these actions. The difference between the participants creates uncertainty. It is important to understand the weaknesses in measures to address system requirements in the early iterations of system development. This will allow appropriate measures to be taken to improve the quality of measures to address system requirements. This paper proposes the use of Bayesian methods to evaluate the development of requirements for the creation of a decision support system. A model is proposed in which the participants of the events evaluate the measures in terms of addressing all issues and uncertainties. After the implementation of the requirements discussed at the events, the results of testing are evaluated for these activities. The analysis of the assessments provided by the participants of the activities and evaluations, based on the test results, provides an opportunity to draw appropriate conclusions and take appropriate measures. During the evaluation process, type I errors occur — the activities were evaluated by the participants on «3», which meant that not all issues were resolved and problems exist, and as a result no errors were made in implementing the precedents worked on at these events. Type II error — the measures were evaluated by the participants on «5», which meant that all issues were resolved and there were no unresolved issues, and as a result errors were obtained in the implementation of precedents, which were worked out at these events. The article processes the initial data. The historical representation is determined: P(T|D) = P(D,T)/P(D). The posterior representation is determined: P(D|T) = P(D,T)/P(T). Using this mathematical model, we can assess the quality of processing the requirements for the creation of DSS. In the case of obtaining low values of P(D1|T1), P(D2|T2), P(D3|T3) it can be concluded that the measures to process the requirements are not carried out at the appropriate level and may need to be carried out differently. In the case of obtaining low values of P(D3|T1), P(D1|T3) it can be concluded that the measures to process the requirements are carried out at the appropriate level and the probability of errors of I and II kind is quite low. Based on the results of the work on the creation of the first and second stages of DSS, it is possible to draw conclusions and make organizational decisions, and as a result, other stages of the creation of DSS will be better than the first and second stages. More and more activities are moving to the electronic form, the implementation of the function of estimating the processing of the requirement is becoming easier, so research in this area has prospects.

Web-Based Information Systems: Developing a Design Theory

The purpose of this research is to determine a proposed taxonomy that classified information systems theory concerning how four main objectives are handled namely analysis, explanation, prediction, and prescription. This research used a descriptive qualitative and experimental research methods. This information technology system design stage is the stage after the analysis of the information technology system development cycle. The results show the definition of system requirements for information technology, preparation for design, or implementation describes how an information technology system can be formed. It can be seen in the form of planning, drawing, making a sketch, or arrangement of several separate elements into a unified whole and functioning. In conclusion, the most important thing in the development of information systems is the user and the system should be integrated.

Structuring the context for construction robot development through integrated scenario approach

The technological development of construction robots is underway globally. However, current development activities face significant uncertainties, particularly in terms of the definition and management of system requirements, which are primarily based on vague assumptions about the future. Thus, a new tool is required to grasp how construction robots—and their surrounding ecosystems—will be used. This research adopts an unprecedented scenario-based approach to develop and analyze future alternatives for construction robotics in a systematic manner. Hong Kong “toward 2035” is used as an initial test case, and four scenarios of the robot ecosystem, i.e., “Bottleneck,” “Age of Iron Worker,” “Dynamic Co-evolution of Robotization and Modularization,” and “Rise of the Robots,” are developed from evidence-based analysis. Scenarios highlight the crucial role of workers for construction robot utilization. Driving forces, opportunities, and challenges are identified for elaborating strategies under each scenario. The integrated scenario approach and findings lay an important foundation for systems engineering processes in construction robotics to develop a new tool for structuring system context and specifying system requirements.

ANGULAR MOVEMENT PROGRAM CALCULATION PROCEDURE SPACECRAFT WHEN TAKING THE SURFACE OF THE EARTH IN AREA MODE

Currently increased interest in satellite images of the Earth's surface with high resolution terrain (1 to 10 m). To obtain such images, you must use a long focus optical system (OS) having a limited field of view that does not allow the images of the large width. To increase the effectiveness of shooting in modern space systems (SS) Earth observation provides the opportunity after shooting a segment of the Earth's surface to redirect the OS to another area and spend it shooting. With sufficient speed shift OS it is possible to survey two or more adjacent parcels, which is almost equivalent to the corresponding increase in the width of the field of view of the removing apparatus. In this connection there is the task of restoring the OS, which is solved by the use of appropriate hardware and software control the angular movement of the removing apparatus. When creating the SS there is also the need to solve the following tasks: calculation of the program angular motion in a given length of the removable sections and a predetermined number of adjacent strips to be shot, with the purpose of definition of system requirements, spacecraft (SC) control and calculation under given characteristics of the system orientation of the SC possible number of the maximum length and remove adjacent portions of the surface of the Earth. To solve these tasks the mathematical model software of angular motion of the SC. Given the necessary initial data, mathematical model and method of calculation of kinematic parameters of a software angular motion of a SC in the mode of area highway shooting adjacent sections of the Earth's surface located at a predetermined distance from a trace route SC; examples and results of numerical calculations of the programmes angular motion by moving the instrument in remote sensing.

Airborne Wind Vector Scatterometer for Sea Surface Measurements

This paper describes the development of an Airborne Wind Vector Scatterometer for low-resolution wind speed measurements. The scatterometer is designed to meet a wind speed accuracy requirement of 1 m/s. In this <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ad hoc</i> and low-budget project, the development of the instrument exploited some already existing subsystems. The development started from the definition of the scientific system requirements and ended with two experimental flights for wind vector retrieval from three test areas in the Gulf of Finland, the Baltic Sea. One of the flights was planned for a simultaneous overpass with the TDS-1 satellite that was conducting Global Navigations Satellite System – Reflectometry (GNSS-R) measurements. The results confirm the measurement capabilities of the GNSS-R technology and the desired 1 m/s wind speed accuracy of the scatterometer that was developed.

MODULINIO PROJEKTAVIMO TAIKYMO PASLAUGOMS PROBLEMATIKA / PROBLEMATIC OF SERVICE MODULARISATION

Maintaining a competitive edge in today’s markets with short product life cycles and competitors quickly copying commercial success ideas is a significant challenge. Service organisations have to look for ways to quickly adapt to environmental changes and offer the most satisfying services to demanding and rushing customers. One of the possible ways to achieve these goals is to apply the principles of modular design to services. Although the modular design is widely used in the production of goods, its applicability to services has not yet been sufficiently researched. There is a lack of consensus on the terms used, there is no clear definition of the modular service system requirements, there are many doubts in the application of quantitative decision methods for modular service system management, and so forth. The article aims to identify the fundamental problems associated with the use of modular design for services. Based on the results of the analysis of the scientific literature, we propose a scheme describing the service system, and identify the important problematic issues related to the application of modular design to services. In this paper, we use methods of systematic analysis, abstraction, synthesis, and critical analysis.

Critical Success Factors of System Requirements Definition in IT System Development: An Industrial Case Study

The success of IT system development is largely dependent on the System Requirements Definition (SRD) phase. Researches on Critical Success Factors (CSFs) in the SRD phase are beneficial to the success of IT system development. However, reports that consider the situation in the system requirements definition phase is lacking and these studies try to develop universal truths for CSFs without lessons learnt from empirical evidence need to be characterized. This study is a step towards bridging this gap in characterized evidence to discover “difficult items” in the SRD phase. Moreover, we conducted a case study to justify the importance of CSFs that could be 1) Customer/User Involvement, 2) Clear project goals, and 3) Technical skills of the project team in the SRD phase. The results of the characterization indicated that those major CSFs are consistent. Another issue can also be mitigated by examining Agile method.

Critical Success Factors of System Requirements Definition in IT System Development: An Industrial Case Study.

The success of IT system development is largely dependent on the System Requirements Definition (SRD) phase. Researches on Critical Success Factors (CSFs) in the SRD phase are beneficial to the success of IT system development. However, reports that consider the situation in the system requirements definition phase is lacking and these studies try to develop universal truths for CSFs without lessons learnt from empirical evidence need to be characterized. This study is a step towards bridging this gap in characterized evidence to discover “difficult items” in the SRD phase. Moreover, we conducted a case study to justify the importance of CSFs that could be 1) Customer/User Involvement, 2) Clear project goals, and 3) Technical skills of the project team in the SRD phase. The results of the characterization indicated that those major CSFs are consistent. Another issue can also be mitigated by examining Agile method.

Privacy and security of electronic patient records – Tailoring multimethodology to explore the socio-political problems associated with Role Based Access Control systems

Multimethodologies are now an established area of ‘soft’ operations research (OR). Adopting appropriate OR methods to tackle unstructured and complex problems is a promising field of inquiry and potential application. Research in the areas of energy and utilities, education, UK public services, and healthcare has demonstrated the success of applying multimethodologies to practice. This research focused on the socio-political and socio-cultural issues associated with the specification and design of a Role Based Access Control (RBAC) system as a precursor to the adoption of an electronic health and patient record system in an English National Health Service (NHS) hospital Trust. Although being a local hospital Trust initiative, there were many complex requirements and constraints from UK NHS policies, strategies and standards, as well as from government contracted IT company vendors, consultancy companies and software consortia (termed Local Service Providers). This research develops a multimethodology, using SSM in combination with process modelling and technology management (referred to as TMSSMXL), in order to tailor problem structuring methods to a healthcare hospital context. The research concludes that by adopting methods that are compatible with an organization's culture, stakeholder perspectives and professional working, a suitable mix of OR methods may be combined and deployed that can enable, and enhance, stakeholders’ knowledge and learning about the unforeseen organizational consequences of complex technology introduction. It is argued that this leads to more effective technology systems requirements definition and greater project implementation success.

Declarative Approach Design Technique: Requirements Analysis

Рассматриваются актуальные проблемы современных методов проектирования программного обеспечения. Основными недостатками современных методов проектирования программного обеспечения являются несоответствие быстро меняющимся требованиям в условиях стремительно развивающейся индустрии информационных технологий, сложность сопровождения и поддержки программного обеспечения из-за преобладания императивной составляющей и слабой степени документированности. Дана характеристика предметно ориентированного метода проектирования (Domain Driven Design), определены преимущества и недостатки рассматриваемого метода. Сделан вывод о необходимости создания новой методики, учитывающей особенности и требования современных процессов проектирования. Предложена методика декларативного процесса проектирования, рассматривающая процесс проектирования в виде последовательных этапов: определение требований к системе, анализ, проектирование и разработка. Данная методика основана на формальных правилах декларативного перехода между различными состояниями процесса проектирования. Рассмотрены этапы определения требований к системе и анализа с использованием предлагаемой методики на примере проектирования системы проведения онлайн-соревнований по спортивному программированию BACS. На этапе формулирования требований к системе был определен словарь предметной области. Результатом этапа анализа является модель предметной области, формальное определение внешних характеристик процессов и зависимости процессов друг от друга, представленной в виде диаграммы вариантов использования. Полученные описания и диаграммы являются входными данными для следующего этапа «Проектирование».

Greenhouse Module for Space System: A Lunar Greenhouse Design

Abstract In the next 10 to 20 years humankind will return to the Moon and/or travel to Mars. It is likely that astronauts will eventually build permanent settlements there, as a base for long-term crew tended research tasks. It is obvious that the crew of such settlements will need food to survive. With current mission architectures the provision of food for longduration missions away from Earth requires a significant number of resupply flights. Furthermore, it would be infeasible to provide the crew with continuous access to fresh produce, specifically crops with high water content such as tomatoes and peppers, on account of their limited shelf life. A greenhouse as an integrated part of a planetary surface base would be one solution to solve this challenge for long-duration missions. Astronauts could grow their own fresh fruit and vegetables in-situ to be more independent from supply from Earth. This paper presents the results of the design project for such a greenhouse, which was carried out by DLR and its partners within the framework of the Micro-Ecological Life Support System Alternative (MELiSSA) program. The consortium performed an extensive system analysis followed by a definition of system and subsystem requirements for greenhouse modules. Over 270 requirements were defined in this process. Afterwards the consortium performed an in-depth analysis of illumination strategies, potential growth accommodations and shapes for the external structure. Five different options for the outer shape were investigated, each of them with a set of possible internal configurations. Using the Analytical Hierarchy Process, the different concept options were evaluated and ranked against each other. The design option with the highest ranking was an inflatable outer structure with a rigid inner core, in which the subsystems are mounted. The inflatable shell is wrapped around the core during launch and transit to the lunar surface. The paper provides an overview of the final design, which was further detailed in a concurrent engineering design study. During the study, the subsystem parameters (e.g. mass, power, performance) were calculated and evaluated. The results of the study were further elaborated, leading to a lunar greenhouse concept that fulfils all initial requirements. The greenhouse module has a total cultivation area of more than 650 m² and provides more than 4100 kg of edible dry mass over the duration of the mission. Based on the study, the consortium also identified technology and knowledge gaps (not part of this paper), which have to be addressed in future projects to make the actual development of such a lunar greenhouse, and permanent settlements for long-term human-tended research tasks on other terrestrial bodies, feasible in the first place.

Study on Critical Success Factors Estimation in IT System Development

The success of IT system development largely depends on the System Requirements Definition (SRD) phase. Researches on Critical Success Factors (CSFs) in the SRD phase are very few. This paper aims to make clear the CSFs in the SRD phase of IT system development. To achieve this, first, interviews to discover “difficult items” in the SRD phase were executed to participants who were engaged in three highly advanced IT system developments. Second, major difficult items were extracted from the interview results. Third, CSFs estimation was executed from the extracted major difficult items. Then, the estimated CSFs were compared to those obtained from the interviews. As a result, CSFs were found to be almost the same between those estimated and interviewed. Through this research, it can be concluded that 1) Customer/User Involvement, 2) Clear project goals, and 3) Technical skills of the project team are the major CSFs in the SRD phase

Decision Support System Requirements Definition for Human Extravehicular Activity Based on Cognitive Work Analysis.

The design and adoption of decision support systems within complex work domains is a challenge for cognitive systems engineering (CSE) practitioners, particularly at the onset of project development. This article presents an example of applying CSE techniques to derive design requirements compatible with traditional systems engineering to guide decision support system development. Specifically, it demonstrates the requirements derivation process based on cognitive work analysis for a subset of human spaceflight operations known as extravehicular activity. The results are presented in two phases. First, a work domain analysis revealed a comprehensive set of work functions and constraints that exist in the extravehicular activity work domain. Second, a control task analysis was performed on a subset of the work functions identified by the work domain analysis to articulate the translation of subject matter states of knowledge to high-level decision support system requirements. This work emphasizes an incremental requirements specification process as a critical component of CSE analyses to better situate CSE perspectives within the early phases of traditional systems engineering design.

Co-Conception Process of an Innovative Assistive Device to Track and Find Misplaced Everyday Objects for Older Adults with Cognitive Impairment: The TROUVE Project

Purpose: Misplacing or losing personal belongings is a concern of everyday life among people of all ages. Older adults with cognitive impairment are significantly more affected by this problem. It is a source of frustration, anxiety, interpersonal conflict and disability in this population. Informal caregivers are greatly impacted by this problem, which compels them to spend a lot of time searching for misplaced items and comforting the person. Assistive technology could thus be of great benefit in this area. However, existing item locator devices do not appear to meet the needs of older adults with cognitive disorders. The TROUVE project aims to conceive and assess an innovative item locator device that effectively addresses their needs, capacities, and goals.Procedure: The project team conducted a co-design process involving relevant stakeholders (persons with cognitive impairment, informal and formal caregivers, researchers, industry representatives, ethical bodies) using user-tests, focus groups, interviews, and questionnaires. The project plan involved three phases: (1) analysis of end-users' needs, (2) definition of system requirements and iterative prototype development, and (3) prototype assessment.Findings: The analysis of end users' needs and the evaluation of existing item locator devices provided us with details about the items which are the most frequently lost or misplaced by older adults at home and their coping strategies to manage these situations. The analysis of usability problems observed throughout the assessment of existing devices allowed the definition of the system requirements. Prototype assessment showed that spatialized sound can be used to help these users find missing items, and that an item locator device can be part of a more comprehensive assistive and rehabilitation system such as a robot.Conclusions: An item locator that relies on sensory information (spatialized sound) rather than on conceptual reasoning (“the item is located to your left 4 meters away”) appears to be an interesting solution to address the problem of misplacing personal items in elderly with cognitive impairment. Involving end-users and relevant stakeholders throughout the cycle of design and development of assistive technology is an effective method to explore design opportunities and define creative solutions.