Easy concurrency

Advances in technology raise expectations. As far as software engineering is concerned, the common expectation is that coding and deploying applications is going to be simple. It seems, though, that software engineering is not getting easier, and the complexity moves to an application domain. One of the sources of complexity is an application concurrency. It is not an uncommon development practice that concurrency and transaction management in multi-user, multi-threaded, event-driven applications are postponed until after most of the required functionality is implemented. This situation has various explanations. On the one hand, business logic may require access and modification of large sets of inter-connected application objects. On the other, testing and stress-testing of this logic becomes possible only at advanced stages of product development. At these stages, increasing lock granularities may appear to be less "expensive" than debugging race conditions and deadlocks. Coarse-grained locking has, of course, an adverse effect on application scalability. Declaring rules of concurrency outside of the application may solve part of the problem. This paper presents an approach allowing developers to define concurrency in application-specific terms, design it in the early stages of development, and implement it using a documented API of the concurrency engine (CE). Simple notation makes it possible to record concurrency specifications in terms of application operations, relationships between application resources, and synchronization conflicts between operations. These concepts are demonstrated on examples. The final sections include the CE UML diagram, notes on API usage, and performance benchmarks. Published online: 25 July 2001     

Model development guidelines for UML-RT: conventions,patterns and antipatterns

Software development guidelines are a set of rules which can help improve the quality of software. These rules are defined on the basis of experience gained by the software development community over time. This paper discusses a set of design guidelines for model-based development of complex real-time embedded software systems. To be precise, we propose nine design conventions, three design patterns and thirteen antipatterns for developing UML-RT models. These guidelines have been identified based on our analysis of around 100 UML-RT models from industry and academia. Most of the guidelines are explained with the help of examples, and standard templates from the current state of the art are used for documenting the design rules.     

Propagating experience-based accessibility guidelines to user interface development

This paper presents a methodological approach towards the integration of accessibility guidelines into the user interface development life cycle. The term accessibility guidelines refers to the consolidated design wisdom, as documented in general recommendations, principles of good practice, experience-based heuristics or otherwise ‘blessed’ rules, regarding the construction of interactive computer-based software for people with disabilities. At the core of the proposed method is the use of a design repository and a supporting tool environment capable of encapsulating, customizing and reusing experience-based accessibility wisdom, so as to facilitate the integration of previously generated, tested and agreed, accessibility recommendations into new design cases and user interface implementations. It is argued that the proposed approach eliminates some of the limitations or shortcomings associated with more conventional methods, such as the use of paper-based guidelines, or reviews by experts, while it facilitates more effective communication amongst designers and developers of user interfaces.     

Designing and implementing lightweight kernels for capability computing

In the early 1990s, researchers at Sandia National Laboratories and the University of New Mexico began development of customized system software for massively parallel ‘capability’ computing platforms. These lightweight kernels have proven to be essential for delivering the full power of the underlying hardware to applications. This claim is underscored by the success of several supercomputers, including the Intel Paragon, Intel Accelerated Strategic Computing Initiative Red, and the Cray XT series of systems, each having established a new standard for high‐performance computing upon introduction. In this paper, we describe our approach to lightweight compute node kernel design and discuss the design principles that have guided several generations of implementation and deployment. A broad strategy of operating system specialization has led to a focus on user‐level resource management, deterministic behavior, and scalable system services. The relative importance of each of these areas has changed over the years in response to changes in applications and hardware and system architecture. We detail our approach and the associated principles, describe how our application of these principles has changed over time, and provide design and performance comparisons to contemporaneous supercomputing operating systems. Copyright © 2008 John Wiley & Sons, Ltd.     

A method and tool for the design of educational multimedia material

Abstract This paper deals with the problem of the specification of the pedagogic design of interactive multimedia and specific telematics applications developed for use in education. A method to specify the design and a supporting tool (SHOC-TOOL) are described. The idea is that the use of such a method and tool can make the development process more efficient and can lead to a more professional approach to the pedagogic design of educational software in general. Resulting design specifications can be assessed for completeness, allow for comparisons among designs and are relatively easy to read for others than the designer himself. The method and the tool both stimulate the re-use of existing design and code segments. SHOC-TOOL is described along with several examples from real practice. The paper concludes with a discussion of the experience of its introduction and use.     

A UML-based static verification framework for security

Secure software engineering is a new research area that has been proposed to address security issues during the development of software systems. This new area of research advocates that security characteristics should be considered from the early stages of the software development life cycle and should not be added as another layer in the system on an ad-hoc basis after the system is built. In this paper, we describe a UML-based Static Verification Framework (USVF) to support the design and verification of secure software systems in early stages of the software development life-cycle taking into consideration security and general requirements of the software system. USVF performs static verification on UML models consisting of UML class and state machine diagrams extended by an action language. We present an operational semantics of UML models, define a property specification language designed to reason about temporal and general properties of UML state machines using the semantic domains of the former, and implement the model checking process by translating models and properties into Promela, the input language of the SPIN model checker. We show that the methodology can be applied to the verification of security properties by representing the main aspects of security, namely availability, integrity and confidentiality, in the USVF property specification language.     

Improving active participation during enterprise operations modeling with an extended story-card-method and participative modeling software

The COVID-19 pandemic emphasized the need for process automation, using agile software development practices. However, when agile methods are used in scaled contexts, many software development efforts fail, mainly due to lacking requirements engineering practices. When business-oriented software needs to be developed within a scaled context, the story-card method (SCM), developed as part of a previous study, assists in structuring emerging software requirements within a taxonomy that represents enterprise operation. The SCM helps agile team members to develop a common understanding about enterprise operation when they construct the enterprise operation taxonomy. Digital participatory enterprise modeling (PEM) may increase collaboration and understanding among team members, especially when team members are geographically dispersed, when they co-model their understanding of enterprise operations. Using design science research to further evolve the existing SCM, we identified two concerns regarding the existing SCM: (1) The modeling software did not encourage active participation during modeling, and (2) Low quality of the resulting cooperation structure diagram (CSD) that is used to derive an enterprise operation taxonomy, i.e., the need to further extend the existing SCM. As main contribution of this article, we addressed previous deficiencies of the SCM, developing an extended SCM (eSCM), based on principles and guidelines that would encourage online participation during PEM, also providing a comprehensive case to demonstrate the eSCM. As a second contribution, we used survey-feedback from research participants, as well as activity tracking to evaluate whether the modeling tool encouraged active PEM. Our third contribution is to evaluate the quality of the resulting CSDs with suggestions for future improvement.

     

A multi-agent legal recommender system

Infonorma is a multi-agent system that provides its users with recommendations of legal normative instruments they might be interested in. The Filter agent of Infonorma classifies normative instruments represented as Semantic Web documents into legal branches and performs content-based similarity analysis. This agent, as well as the entire Infonorma system, was modeled under the guidelines of MAAEM, a software development methodology for multi-agent application engineering. This article describes the Infonorma requirements specification, the architectural design solution for those requirements, the detailed design of the Filter agent and the implementation model of Infonorma, according to the guidelines of the MAAEM methodology.     

Zodiac: A history-based interactive video authoring system

Easy-to-use audio/video authoring tools play a crucial role in moving multimedia software from research curiosity to mainstream applications. However, research in multimedia authoring systems has rarely been documented in the literature. This paper describes the design and implementation of an interactive video authoring system called Zodiac, which employs an innovative edit history abstraction to support several unique editing features not found in existing commercial and research video editing systems. Zodiac provides users a conceptually clean and semantically powerful branching history model of edit operations to organize the authoring process, and to navigate among versions of authored documents. In addition, by analyzing the edit history, Zodiac is able to reliably detect a composed video stream's shot and scene boundaries, which facilitates interactive video browsing. Zodiac also features a video object annotation capability that allows users to associate annotations to moving objects in a video sequence. The annotations themselves could be text, image, audio, or video. Zodiac is built on top of MMFS, a file system specifically designed for interactive multimedia development environments, and implements an internal buffer manager that supports transparent lossless compression/decompression. Shot/scene detection, video object annotation, and buffer management all exploit the edit history information for performance optimization.     

SESAG: an object-oriented application framework for real-time systems

Advancements in hardware and software technologies have made possible the design of real-time systems and applications where stringent timing constraints are imposed on critical tasks. The design of such systems is more complex than that of temporally unrestricted systems because system correctness depends on the satisfaction of functional as well as temporal requirements. To aid users in correctly and efficiently designing systems, object-oriented frameworks provide a useful environment for significant reuse and reduction in design effort. In contrast to other application domains, there has been relatively little work on an application framework for the design of real-time systems. Facing the growing need for real-time applications, we propose a novel application framework called SESAG, which consists of five components, namely Specifier, Extractor, Scheduler, Allocator, and Generator. Within SESAG, several design patterns are proposed and used for the development of real-time applications. A new evaluation metric called relative design effort is proposed for evaluating SESAG. Experiences in using SESAG show a significant increase in design productivity through design reuse and a significant decrease in design time and effort. Two complex application examples have been developed using SESAG and evaluated using the new evaluation metric. The examples demonstrate relative design efforts of at most 18% of the design efforts required by conventional methods. Copyright © 2005 John Wiley & Sons, Ltd.     

Design verification in model-based?��-controller development using an abstract component

Component-based software development is a promising approach for controlling the complexity and quality of software systems. Nevertheless, recent advances in quality control techniques do not seem to keep up with the growing complexity of embedded software; embedded systems often consist of dozens to hundreds of software/hardware components that exhibit complex interaction behavior. Unanticipated quality defects in a component can be a major source of system failure. To address this issue, this paper suggests a design verification approach integrated into the model-driven, component-based development methodology Marmot. The notion of abstract components—the basic building blocks of Marmot—helps to lift the level of abstraction, facilitates high-level reuse, and reduces verification complexity by localizing verification problems between abstract components before refinement and after refinement. This enables the identification of unanticipated design errors in the early stages of development. This work introduces the Marmot methodology, presents a design verification approach in Marmot, and demonstrates its application on the development of a μ-controller-based abstraction of a car mirror control system. An application on TinyOS shows that the approach helps to reuse models as well as their verification results in the development process.     

Avoiding metric monsters: A design metrics approach

Metric monsters are stumbling blocks that prevent software metrics-guided methodologies from attaining product and process improvement. Metric monsters can occur during the identification, collection or application of software metrics. In our research, we have developed and tested our design metrics over a five-year period and have found them to be excellent predictors of error-prone modules. Based on this research, we will identify some of the monsters that occur in the quantitative analyses of software and its development processes, and present our approach in formulating a design metrics model that avoids these monsters. This model consists of software tools, guidelines and actions for the application of software design metrics.     

A platform for P2P agent-based collaborative applications

The operational environment can be a valuable source of information about the behavior of software applications and their usage context. Although a single instance of an application has limited evidence of the range of the possible behaviors and situations that might be experienced in the field, the collective knowledge composed by the evidence gathered by the many instances of a same application running in several diverse user environments (eg, a browser) might be an invaluable source of information. This information can be exploited by applications able to autonomously analyze how they behave in the field and adjust their behavior accordingly. Augmenting applications with the capability to collaborate and directly share information about their behavior is challenging because it requires the definition of a fully decentralized and dependable networked infrastructure whose nodes are the user machines. The nodes of the infrastructure must be collaborative, to share information, and autonomous, to exploit the available information to change their behavior, for instance, to better accommodate the needs of the users to prevent known problems. This paper describes the initial results that we obtained with the design and the development of an infrastructure that can enable the execution of collaborative scenarios in a fully decentralized way. Our idea is to combine the agent-based paradigm, which is well suited to design collaborative and autonomous nodes, and the peer-to-peer paradigm, which is well suited to design distributed and dynamic network infrastructures. To demonstrate our idea, we augmented the popular JADE agent-based platform with a software layer that supports both the creation of a fully decentralized peer-to-peer network of JADE platforms and the execution of services within that network, thus enabling JADE multiagent systems (MASs) to behave as peer-to-peer networks. The resulting platform can be used to study the design of collaborative applications running in the field.     

User-story driven development of multi-agent systems: A process fragment for agile methods

Agile software development methods are mostly built as a set of managerial guidelines and development concepts on how to handle a software development but are not bounded to software development paradigms like object or agent orientation. Some methods, like eXtreme Programming and SCRUM are driven by operational requirements representation models called User Stories. These User Stories can be used as an anchoring point to agile methods; this means that we could take a User Stories set to drive a software transformation approach embedded in a particular development paradigm. This paper presents a process fragment for Multi-Agent Systems development with agile methods based on User Stories sets. The process fragment indeed takes advantage of an initial set of User Stories to build a reasoning model (called the Rationale Tree; typically several of these are built for a single project) that documents decompositions and means-end alternatives in scenarios for requirements realization. A Rationale Tree can then be aligned with a Multi-Agent design and implemented in an agent-oriented development language. In this paper the transformation is targeted to the JAVA Agent DEvelopment (JADE) framework. The process fragment (at least partially) covers the Requirements Analysis, Multi-Agent System Design and Multi-Agent System Implementation phases. Transformation from one phase to the other is overseen and illustrated on an example.     

A framework for efficient and rapid development of cross-platform audio applications

In this article, we present CLAM, a C++ software framework, that offers a complete development and research platform for the audio and music domain. It offers an abstract model for audio systems and includes a repository of processing algorithms and data types as well as all the necessary tools for audio and control input/output. The framework offers tools that enable the exploitation of all these features to easily build cross-platform applications or rapid prototypes for media processing algorithms and systems. Furthermore, included ready-to-use applications can be used for tasks such as audio analysis/synthesis, plug-in development, feature extraction or metadata annotation. CLAM represents a step forward over other similar existing environments in the multimedia domain. Nevertheless, it also shares models and constructs with many of those. These commonalities are expressed in the form of a metamodel for multimedia processing systems and a design pattern language.     

Understanding design patterns — what is the problem?

Design patterns codify proven solutions to recurring design problems. Their proper use within a development context requires that: (i) we understand them; (ii) we ascertain their applicability or relevance to the design problem at hand; and (iii) we apply them faithfully to the problem at hand. We argue that an explicit representation of the design problem solved by a design pattern is key to supporting the three tasks in an integrated fashion. We propose a model‐driven representation of design patterns consisting of triples < MP, MS, T > where MP is a model of the problem solved by the pattern, MS is a model of the solution proposed by the pattern, and T is a model transformation of an instance of the problem into an instance of the solution. Given an object‐oriented design model, we look for model fragments that match MP (call them instances of MP), and when one is found, we apply the transformation T yielding an instance of MS. Easier said than done. Experimentation with an Eclipse Modeling Framework‐based implementation of our approach applied to a number of open‐source software application's raised fundamental questions about: (i) the nature of design patterns in general, and the ones that lend themselves to our approach, and (ii) our understanding and codification of seemingly simple design patterns. In this paper, we present the principles behind our approach, report on the results of applying the approach to the Gang of Four (GoF) design patterns, and discuss the representability of design problems solved by these patterns. Copyright © 2011 John Wiley & Sons, Ltd.