A Comparative Study of Software Architectures for Embedded Mission Critical Applications

Introduces a systematic and defined process called "comparison of design methodologies" (CDM) for objectively comparing software design methodologies (SDMs). We believe that using CDM will lead to detailed, traceable, and objective comparisons. CDM uses process modeling techniques to model SDMs, classify their components, and analyze their procedural aspects. Modeling the SDMs entails decomposing their methods into components and analyzing the structure and functioning of the components. The classification of the components illustrates which components address similar design issues and/or have similar structures. Similar components then may be further modeled to aid in more precisely understanding their similarities and differences. The models of the SDMs are also used as the bases for conjectures and analyses about the differences between the SDMs. This paper describes three experiments that we carried out in evaluating CDM. The first uses CDM to compare Jackson System Development (JSD) and Booch's (1986) object-oriented design. The second uses CDM to compare two other pairs of SDMs. The last one compares some of our comparisons with other comparisons done in the past using different approaches. The results of these experiments demonstrate that process modeling is valuable as a powerful tool in analysis of software development approaches.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

: The purpose of this report is to provide general information concerning software design methodologies to technical management personnel. In particular, the report is aimed at managers who are in the planning stages of a software development and are facing the decisions of whether to use a formal design methodology and which methodology to use. To accomplish this objective a definition of design methodology is presented, explained and illustrated. Major design philosophies are discussed and the kinds of applications which they address are described. Following this introductory information, various management perspectives on software design methodologies are presented. In general, these perspectives pertain to the current state of software design methodology development and support tools, as well as relevant application experiences. (author)

Designing software for provable correctness: The direction for quality software

The teaching and practice of software design concepts early in a CIS curriculum

Commercial off-the-shelf (COTS) software products are being included in ever more complex and critical systems. There are clearly advantages to considering the use of COTS in such systems, but given the rigorous needs of such critical systems or subsystems, there are concerns about the suitability of COTS software for such applications. The AIAA’s Software Systems Technical Committee and the AIAA’s Computer Systems Technical Committee have undertaken an effort to produce a guidebook that captures issues related to the consideration and use of COTS products in these large, complex systems, with a special emphasis on those risks and risk mitigation approaches that relate to mission critical systems. This guidebook identifies a set of characteristics of mission critical systems that makes the consideration, selection and validation processes of COTS products (hardware, software, subsystems, etc.) an emerging factor in systems definition, development and acceptance. The guidebook discusses a large number of risk areas related to using COTS software products in mission critical systems and identifies various mitigation approaches to the risks. It includes detailed processes for selecting and evaluating the products and considerations for using COTS software products within the overall context of the software development life cycle standardized in IEEE/EIA 12207. Mission critical system characteristics such as reliability, safety, availability, maintainability and certification tend to influence whether or not COTS software should be considered for a given application. Once the suitability of COTS software has been determined, then it is possible that additional requirements may be placed on the product and/or the product’s vendor for such mission critical applications. Further, it is possible that certain system requirements and expectations may need to be modified because of the inclusion of COTS software products in that system. As COTS products continue to be considered as candidates for inclusion within mission critical systems, there are likely to be additional concerns and factors to emerge that will influence how both acquirers and suppliers decide if and/or when to use COTS products. Ongoing monitoring of this technology area seems to be warranted.

Formal inference processes in all kinds of engineering designs are based on the cognitive process and means of abstraction. This paper presents a formal treatment of system design. It first discusses the differences of system designs in abstract and concrete systems. A hierarchical abstraction model of system descriptivity (HAMSD) is developed that explains the abstract levels of entities and artifacts in both the concrete world and the abstract world. The HAMSD model classifies the design of a system at five levels known as the levels of (1) analogue objects, (2) diagrams, (3) natural languages, (4) professional notations, and (5) mathematics from the bottom up. According to the HAMSD model, an architectural, functional, or behavioral design of a system should adopt a higher-level abstract means to describe the system at a given abstract level, in order to obtain more powerful descriptivity and higher accuracy. Therefore, a mechanical system may be designed by using diagrams; while an information or software system can not be precisely described by diagrams. The reason is that the former is at an abstract level lower than the descriptive means of diagrams, but not so is the latter. Applications of the above findings in dealing with complicated problems in large-scale software system designs are discussed in the context of software engineering. Real-time process algebra (RTPA) is adopted as a highly abstract means in case studies on formal methodologies of software system design and modeling for software objects and design patterns.

3 - Design Principles

Design pattern detection is a popular re-engineering job in software development. It provides essential information to the developers to recognize, sustain, and recycle the software. This article proposes a graph matching algorithm using a correlation-based feature selection technique to discover the design pattern (DP) instances from the software or system design. Usually, the feature selection method is used to choose the best instances from the dataset, which mostly matches the target feature. However, this paper has applied a correlation feature selection method to match the system design to the design pattern. We have taken three DPs comparing examples for this intention:•the first example for an entire match•the second example for a partial match•the third example of a not matchIn this experiment, we took the Abstract factory DP as a model graph, and the remaining twenty-two DPs are system or DPs. Software instances groups lots of classes and objects we converted into a graph. We observed that three of the 22 DPs are completely matched to the model DP, one pattern is not matched, and the remaining 18 patterns are only partially matched.

A real-time operating system (RTOS) provides a platform for the design and implementation of a wide range of applications in real-time systems, embedded systems, and mission-critical systems. This paper presents a formal design model for a general RTOS known as RTOS+ that enables a specific target RTOS to be rigorously and efficiently derived in real-world applications. The methodology of a denotational mathematics, Real-Time Process Algebra (RTPA), is described for formally modeling and refining architectures, static behaviors, and dynamic behaviors of RTOS+. The conceptual model of the RTOS+ system is introduced as the initial requirements for the system. The architectural model of RTOS+ is created using RTPA architectural modeling methodologies and refined by a set of Unified Data Models (UDMs). The static behaviors of RTOS+ are specified and refined by a set of Unified Process Models (UPMs). The dynamic behaviors of the RTOS+ system are specified and refined by the real-time process scheduler and system dispatcher. This work is presented in two papers; the conceptual and architectural models of RTOS+ is described in this paper, while the static and dynamic behavioral models of RTOS+ will be elaborated in a forthcoming paper.

The paper examined the problem of modeling and design of software computer systems. The article briefly describes the content aspects of the various stages of the implementation of software complexes and systems. The methodology of research and analysis of systems, which uses the method of computer simulation modeling, is given. The aim of the work is to create a new universal approach to the design and implementation of software systems of various levels of complexity. During the study, the following general scientific methods were used: system analysis, synthesis, formalization, modeling, decomposition, structuring, description, comparison. The materials used in the study were: computers and software development tools. As a result of the study proposed a universal agent-module approach to the design and implementation of software systems based on simulation agent-based modeling. The study presents the processes of modeling and designing software systems, their stages, and the possibility of their integration within the described approach. Examples of formal model and structure of the software system under design based on the agent-module approach are presented. The proposed approach can be used in the process of software development at the initial stages related to modeling and designing of software systems. Integration of modeling and design stages in the proposed approach will significantly reduce software development time and simplify the design process by making it clearer and more formalized. Materials of the article are of scientific and practical value for a wide range of specialists interested in system analysis, modeling, design and implementation of software systems.

For extended mission utility, it is desirable to be able to reprogram on -orbit payloads for new functions not originally envisioned. The basic concept of modifying payloads in orbit is already proven in that software patches and new coding algorithms can be uploaded to payloads years after launch. The goal of this paper is to discuss the option to extend this reprogrammability to payload hardware, using standards and architectures proven in software -defined radio technology. Next generation payloads using these standards can exploit the increasing versatility and density o f modern Field Programmable Gate Arrays and Digital Signal Processing chips to perform new missions that require onboard wideband, real time processing. I. Introduction HIS paper discusses the application of proven software standards and design methodology to enable next generation multifunction payloads. Even though the physics of specific front -end sensors, emitters and associated electronics in the payload must conform to the original mission, the trend is moving toward increasing generalization and digi tal processing onboard, along with more generalized digital control of the front ends . New missions can take advantage of this trend by relying on generalized hardware that is programmed to be mission specific and reprogrammed as missions change . As onbo ard processing bandwidths increase over time, to tens and hundreds of Megahertz, these missions will benefit from the ever -increasing performance of digital technology in field -programmable gate arrays (FPGAs) to achieve their original and future objective s, increasing the payloads’ effectiveness while reducin g size, weight, power and cost. This approach also benefits operationally responsive satellite missions by reducing the serial development cycle, as a result of reusing common hardware and applying pro ven software to the task of on -orbit reconfiguration. Reconfiguring and reprogramming the FPGA -based payload in the field is similar to sending a new software load to an onboard microprocessor. However, the standards for uploading new functionality to a hardware target are not in such a mature form as for software, which use operating systems and monitor programs that can accommodate new program uploads . This paper specifically suggests the use of modern software -defined radio (SDR) standards to be appl ied more widely, to enable management and upgrading of generalized hardware -based, wideband payload functions. Figure 1 shows the generalized block diagram of a reconfigurable payload.

Design patterns in software development have shown great promise in improving software quality. Traditionally, software developers utilize a set of design patterns to foster reusability and better software design. Recently, mobile applications (apps) have become a mainstay of modern computing, as well as, a challenging domain for software engineers. This is because mobile apps now target more critical domains such as health, banking, m-payments, and even military to mention just a few. Android is a very popular mobile platform, and has managed to take over the majority of mobile market. It is true that there are comprehensive studies in the area of design patterns detection in several object-oriented languages such as Java, C# and C++. However, little studies target design patterns in Android apps. As a step toward helping to measure and explore the application of design patterns in Android apps, we introduce PatRoid, an automated framework for detecting design patterns. PatRoid is a model-based approach that is able to detect design patterns laying inside Android apps source code. The model is based on a graph isomorphism approach, where design patterns are divided into sub-patterns that can be aggregated to formulate design patterns. We have conducted a preliminary evaluation and the results show that PatRoid can detect all of the 23 GoF design patterns.

Software design patterns are documented best practice solutions that can be applied to recurring problems. Although well documented, there are often opportunities to apply them which are overlooked by software designers. This can be the result of inexperience, the sheer complexity of the system, or the fact that design patterns do not always constitute intuitive designs. In this paper, we present a structured methodology for semi-automating the detection of areas within a UML design of a software system that are good candidates for the use of design patterns. This is achieved by the definition of detection rules formalized using the OCL and using a decision tree model. The approach is illustrated on an example GoF design pattern. A prototype tool was developed to show the feasibility of the approach in practical situations, and is used on a case study, producing encouraging results

Software Design Patterns (SDPs) are core solutions to the recurring problems in software. However, adopting SDPs without taking into account their value implications may result in breach of social values and ultimately lead to user dissatisfaction, lack of adoption, and financial loss. An example is the airline system that overcharged people who were trying to escape from the Hurricane Irma. Although not intentional, overlsight of social values in the design of the airline system resulted in significant customer dissatisfaction and loss of trust. To mitigate such value breaches in software design we propose taking social values into account in SDPs explicitly. To achieve this, we outline a collaborative framework that allows for (i) specifying the value implications of SDPs, (ii) developing or extending SDPs for integrating social values, (iii) providing guidance on the value-conscious adoption of design patterns, (iv) collecting and analyzing insights from collaborators, (v) maintaining an up-to-date library of the valufied design patterns, and (vi) incorporating lessons learned from the real-world adoption of the valuefied design patterns into the proposed framework for its continuous improvement in integrating social values into software.

New software design and implementation methodologies are proposed in an attempt to overcome the high failure rate of eHealth projects. These new methodologies and architectures are based on Participatory Design principles, and Model Driven Development techniques. Their possible use is explained in the context of an example application in the coordination of treatment and wellness programs for the frail aged and chronically ill in community care settings.