Fuzzy Control-Based Software Self-Adaptation: A Case Study in Mission Critical Systems

Self-adaptive software (SAS) needs to handle complex software changes at runtime which are multiple, interrelated and unpredictable. However, existing specialized toolkits or platforms for SAS cannot fully assist the software in handling the changes with all the characteristics mentioned above at the same time. Therefore, based on the theories on MultiAgent Systems (MASs) and Search-based Software Engineering (SBSE), this paper proposes a reference architecture of SAS to handle the changes, and provides an Agent-based. Development toolkit and operAtion PlaTform for self-adaptive systems, called ADAPT, to support the development and operation of SAS according to the reference architecture. ADAPT can effectively handle complex changes with Agent technology and search-based planning method. It can also achieve automation in a way to reduce the burden of developers. Moreover, it provides adaptive abilities to SAS from the design time to runtime, reflecting the used methods in the whole process of software engineering.

Self-adaptive software is widely-use for users who need to output varies results after responding from changing environment. The results are normally followed by the Control Theory in order to be constructed in a rigid feedback loop. According to the Control Theory, the controller is designed to measure result errors for the purpose of re-inputs of edited results into the system. The research in the paper proposes an approach to improving the context-aware ability of controller by designing a controller that enhance the self-adaptive software to solve both certain and uncertain problems especially in business. The controller relies on both Control Theory based modules and combination based module, in order to generate outputs including but not limited to activities based on costs or balanced scorecards through adding business context sensors, and create feedback loop to test differences for each module. When the proposed controller is established in self-adaptive software, it is important to extract and filter business information due to user demands, and make software to react itself in a changing environment. In summary, a designed controller model will help self-adaptive software to understand users' need and requirements clearly, so that not only existing parameters could be changed, but also the self-adaptive software can be made to to gain the ability to modify the parameter itself, and more importantly, a good context-aware controlled self-adaptive software could save costs for organisations in addition to improving the effectiveness and efficiency for business in a creative way.

Self-adaptive software is expected to adjust itself attributes or structures at runtime in response to changes. Aiming at addressing some challenging problems such as difficult mathematically modeling software using the current control theoretical methods, we propose a novel fuzzy-control-based approach to achieve self-adaptive software, which is presented as framework of fuzzy self-adaptive software (FFSAS). In this framework, the general model, the implementation architecture, and the design methodology are put forward and discussed in detail. The fuzzy-control-based approach is evaluated with a news-website case study.

With the growing dependency of many technical, commercial, administrative and even social processes from computer software, the number of mission critical software projects rapidly increases. The rapid integration of formerly stand-alone systems into global networks subjects these systems to yet unknown threats. Even mission critical systems may be deliberately manipulated to let malicious attackers access vital system functions or to take over the entire system. Though such systems feature protection mechanism during operation, they are rather vulnerable during their software design and development process. This paper defines a secure software development process to reduce the risk of manipulation and enhance the trustworthiness of critical software produced by renowned manufaturers according to high quality standards. It also explained how this process may be implemented cost efficiently.KeywordsHash FunctionTrust CenterMission Critical SystemMission Critical ApplicationCertificate VerificationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Industries are now moving towards PC-based control from PLC (Programmable Logic Control) based control as the PC (personal computer) is easily available and capable of implementing various control strategies to improve productivity. Advances in both hardware and software technology are expediting this move. Absence of a user friendly, cost effective and easy to apply advanced control strategy based software is the motivation for this work. In this paper we reviewed issues of software application in process control systems. We present the development of an advance process control software tool and its application on a pH neutralization plant. Neural network model based DIC (Direct Inverse Control) strategy is implemented to control the process. The application and results shows the viability and robustness of the advanced control software and its superiority over the conventional PID (proportional–integral–derivative) controller.

This article attempts to address the issues of evaluating self-adaptive software systems, an emerging discipline. Since the field is in its early phase and has not produced enough mature systems for consideration, we try to approach the evaluation issue by considering a descriptive model of selfadaptive software based on control systems. Taking inspirations and using the vocabularies from the feedforward and feedback control paradigms, this article will illustrate the analogous properties in self-adaptive software and its evaluation consideration such as stability and robustness. Existing approaches to self-adaptive software take different aspects, ranging from viewing it as new programming paradigm, new architecture style, new modeling paradigm to a new software engineering principle. This article tries to elicit the evaluation consideration from these different aspects.KeywordsEvaluation MetricsArchitecture StyleProgramming ParadigmModeling ParadigmRuntime BehaviorThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Insights and assessments about the quality, reliability, or trustworthiness of software systems is important for many software applications. Especially for large or mission-critical software systems, reliable measures and assertions are crucial. Since software repositories contain information about source code, software development processes, and team interactions, we extract the provenance of software artifacts from those repositories and store the provenance according to a provenance model defined using W3C PROV data model. We use the recorded provenance to discover insights about the software and its development process, which we apply and evaluate for a large aerospace software system.

Purpose The purpose of this study is to provide a method for designing the software for a process control system that avoids difficulties that lead to safety problems. Design/methodology/approach Design of real-time software for safety critical programmable equipment systems (PES) such as process control or shutdown systems needs to be approached quite differently compared to any other software. It must be designed by those who understand the equipment system not by software engineers who do not. Following the ‘Piper Alpha’ disaster in the North Sea in the late 1980s, it was realised that the software of safety critical PES, such as the shut-down system on an oil rig, was proving very unreliable. Earlier hardwired relay-based shut-down systems were designed by process control engineers who understood the functions the equipment was required to perform; however, by the 1980s, such systems had been replaced by PES designed by system analysts who did not understand the technologies involved. The safety critical real-time software for a programmable equipment system will only be reliable when it is designed by control engineers who understand the functions it has to perform. Findings Bottom-up design of software is necessary to avoid safety issues and this can only be achieved using object-oriented methods. Originality/value This paper describes an entirely original idea of the author based on experience of managing the design and construction of the process control, emergency shut-down and fire and gas and communication systems for a major oil and gas platform in the North Sea around the time of the Piper Alpha disaster.

The Chandra X-ray Center Data System provides end-to-end scientific software support for Chandra X-ray Observatory mission operations. The data system includes the following components: (1) observers' science proposal planning tools; (2) science mission planning tools; (3) science data processing, monitoring, and trending pipelines and tools; and (4) data archive and database management. A subset of the science data processing component is ported to multiple platforms and distributed to end-users as a portable data analysis package. Web-based user tools are also available for data archive search and retrieval. We describe the overall architecture of the data system and its component pieces, and consider the design choices and their impacts on maintainability. We discuss the many challenges involved in maintaining a large, mission-critical software system with limited resources. These challenges include managing continually changing software requirements and ensuring the integrity of the data system and resulting data products while being highly responsive to the needs of the project. We describe our use of COTS and OTS software at the subsystem and component levels, our methods for managing multiple release builds, and adapting a large code base to new hardware and software platforms. We review our experiences during the life of the mission so-far, and our approaches for keeping a small, but highly talented, development team engaged during the maintenance phase of a mission.

Real-time programming has always been one of the most challenging programming disciplines. Real-time programming requires comprehensive command of sequential programming, concurrency, and, of course, time. Real-time programming has many application domains. In this chapter, however, we structure our discussion around digital control systems for the following two reasons. Firstly, digital control systems represent a large portion of real-time software in a diverse set of industries. Examples include automotive power train control systems, aircraft flight control systems, electrical drive systems in paper mills, or process control systems in power plants and refineries. Many of these systems distribute their components over networks with significant communication delays. Therefore, we also discuss networked real-time programming (Section 7). The second reason is pedagogical. Digital control is defined by a set of abstractions that are real-time programmable and mathematically tractable in the context of the dynamics of physio-chemical processes. The abstractions clearly define what application engineers (control engineers) expect of real-time programming. These abstractions therefore constitute a precise definition of the real-time programming problem (Section 2). Control engineers design in difference equations and often use modeling tools such as Simulink to simulate and validate their control models. The part of Simulink most commonly used to specify digital control, i.e., discrete-time with the discrete fixed-step solver and mode:auto, is well-explained by the so-called synchronous semantics [7, 38]. The key abstraction, we call the synchronous abstraction, is that any computation and component interaction happens instantaneously in zero time or with a delay that is exactly the same at each invocation. For example, if a controller computes every 20 msec, either the controller is assumed to read its inputs, compute its control, and write the corresponding outputs instantaneously at the beginning of each period in zero time, or to read its inputs instantaneously at the beginning of the period, compute during the period, and write the corresponding output exactly 20 msec (one period) later. In control parlance, these are the causal and strictly causal cases, respectively. Systems of difference equations can directly be expressed and structured in this model. The inclusion of strictly causal components (components with delays of a period or more) is typically required to break feedback loops and to account for the unavoidable computation or communication delays that will be present in the real control system. Real-time programmers design in interrupt handlers, device drivers, and schedulers, which are concepts on levels of abstraction that are obviously unrelated to difference equations. The result is a conceptual and technical disconnect between control model and real-time code that bedevils many control building projects. The control engineer specifies a Simulink design the real-time programmer finds unimplementable. The realtime programmer then fills in gaps to produce an implementation the control engineer finds uncontrollable. The process of interaction as the two iterate to produce a correct design is prolonged by the different backgrounds of control engineers and real-time programmers. This gap explains many of today’s problems in real-time software design for digital control such as high validation and maintainance overhead as well as limited potential for reusability and scalability.

This research examines the application of environmental control within the Process Control System (PCS) in the aerospace industry, specifically focusing on AS9100 quality assurance. The single case study was conducted at a Malaysian aerospace composite manufacturer, pseudonymously identified as XYZ, due to its significance in the worldwide aerospace supply chain, AS9100 certification, and its position as a leading aerospace composite manufacturer. Using qualitative methods, this study explored the management of temperature, humidity, and contamination in Controlled Contamination Areas (CCA) and Environmentally Monitored Areas (EMA), drawing on observations, PCS document reviews, and semi-structured interviews with key operational personnel. The results of the case study suggest that Company XYZ's PCS achieves compliance and uniformity in operations, but its current conventional approach does not adequately support defect mitigation and process improvement. The study suggests the implementation of an integrated PCS, advocating the use of IoT devices, predictive analytics, and digital twins for real-time control for process reliability. This leads to a decrease in wastage, enhanced product quality, and facilitates the cycle of continual improvement. The study also discusses the roles of quality management system employees, organisational culture, and integrated maintenance as pillars of system sustainment. This research demonstrates the application of integrated environmental control within the PCS and its linkage to operational excellence and global competitiveness to advance the aerospace industry.

In the software engineering (SE) domain the EU challenge on semantic systems and services motivates better support of knowledge creation as well as better access of SE stakeholders to the knowledge they need to perform their activities. Application Lifecycle Management (ALM) is the coordination of development lifecycle activities by process automation, management of relationships between artifacts, and reporting on development progress. ALM focuses on the integration of knowledge between the tools that support SE roles and thus seems particularly well suited to leverage benefits from advanced semantic technologies and services that overcome limitations from semantic gaps in today's heterogeneous SE platforms. In this paper, we present a semantic requirements tracing approach (SemTrace), which makes the implicit interdependencies between requirements and other artifacts explicit. We evaluate the proposed approach in a change impact analysis use case. Initial results show that the SemTrace approach allows for a flexibly identification of semantically connected artifacts in SE projects.

When computational process occurs in uncertain environments, the environmental changes often cause unpredictable influence on the computation. Self-adaptive software is one of the possible ways to tackle and handle this motivation. It evaluates its own behavior and surrounding environment, and adapts itself when the evaluation indicates that it is not accomplishing what the system is intended to do, or when better functionality is possible. Since one of the objectives of role models is to support object adaptation to the environment through role binding mechanism, it is expected that role modeling can be conveniently used to build self-adaptive systems. This paper provides some essential features or mechanisms of self-adaptive systems which are intended to be captured by adaptive role models. We propose Self-Epsilon model, an extension of our developed role-based model Epsilon, to combine and integrate all those features with role-based mechanisms into a single model. This paper also shows how the model can be applied to practically design and implement self-adaptive systems. We illustrate our approach through a case study of a simplified system of coordinated traffic jam monitoring used in some related work. The evaluation shows the reasonable and acceptable scalability of our model implementation in the framework.

With the growing adoption of Industry 4.0 concepts in production systems, new challenges arise in engineering control software. Highly distributed control with tight real-time constraints and safety regulations results in increasingly complex software. Current research focuses on increasing the abstraction with new architectures and modularization of software. The presented PhD research addresses modeling of the interactions between control software components, and of the emergent behavior of these compositions. Such behavior models can support the initial implementation, and facilitate (semi-)automated testing and monitoring of control software. Finally, visualizing behavior in a model can enhance understandability of existing control software, when software developers need not access abstracted hierarchy levels to deduct their functionality. This work aims at optimizing the benefit of behavior models in developing control software: Modeling the expected behavior directly for new software will allow using them throughout the software life-cycle. For legacy software, the initial development effort of behavior models will be minimized by automatically capturing behavior models from the implementation. The approach is evaluated in case studies and user studies to integrate experiences from the industrial domain into this software engineering research.

The development of self-adaptive software (SaS) has specific characteristics compared to traditional one, since it allows that changes to be incorporated at runtime. Automated processes have been used as a feasible solution to conduct the software adaptation at runtime. In parallel, reference model has been used to aggregate knowledge and architectural artifacts, since capture the systems essence of specific domains. However, there is currently no reference model based on reflection for the development of SaS. Thus, the main contribution of this paper is to present a reference model based on reflection for development of SaS that have a need to adapt at runtime. To present the applicability of this model, a case study was conducted and good perspective to efficiently contribute to the area of SaS has been obtained.