Toward a new aspect-mining approach for multi-agent systems

Many aspect mining techniques have been proposed for object-oriented systems. Unfortunately, aspect mining for multi-agent systems is an unexplored research area. The inherent specificities of multi-agent systems (such as autonomy, pro-activity, reactivity, and adaptability) make it difficult to understand, reuse and maintain their code. We propose, in this paper, a (semi-automatic) hybrid aspect mining approach for agent-oriented code. The technique is based on both static and dynamic analyzes. The main motivations of this work are (1) identifying cross-cutting concerns in existing agent-oriented code, and (2) making them explicitly available to software engineers involved in the evolution of agent-oriented code in order to facilitate its refactoring and, consequently, to improve its understandability, reusability and maintainability. The proposed approach is supported by a software tool, called MAMIT (MAS Aspect-MIning Tool), that we developed. The approach and the associated tool are illustrated using a concrete case study.     

A study of software reuse in NASA legacy systems

Software reuse is regarded as a highly important factor in reducing development overheads for new software projects; however, much of the literature is concerned with cost and labor savings that reuse brings to industrial software development and little is known about the inherent risks associated with reuse, particularly in the case of mission and safety-critical software systems. We present the preliminary findings of a research project geared toward assessing the impact of risk in National Aeronautics and Space Administration (NASA) legacy software in flight control systems. We introduce the concept of context variables and the impact they have on reuse within these legacy systems as well as the genealogy classification models, which provide a simple, concise method of mapping reuse between families of software projects. This research was conducted at Global Science and Technology, Inc. under NASA grant number NCC0NNG06GI57G.     

Enriching MATLAB with aspect-oriented features for developing embedded systems

This article presents an approach to enrich the MATLAB¹ language with aspect-oriented modularity features, enabling developers to experiment different implementation characteristics and to acquire runtime data and traces without polluting their base MATLAB code. We propose a language through which programmers configure the low-level data representation of variables and expressions. Examples include specifically-tailored fixed-point data representations leading to more efficient support for the underlying hardware, e.g., digital signal processors and application-specific architectures, without built-in floating point units. This approach assists developers in adding handlers and monitoring features in a non-invasive way as well as configuring MATLAB functions with optimized implementations. Different aspect modules can be used to retarget common MATLAB code bases for different purposes and implementations. We validate the proposed approach with a set of representative examples where we attain a simple way to explore a number of properties. Experiment results and collected aspect-oriented software metrics lend support to the claims on its usefulness.     

Common weaving approach in mainstream languages for software security hardening

In this paper, we propose a novel aspect-oriented approach based on GIMPLE, a language-independent and a tree-based representation generated by the GNU Compiler Collection (GCC), for the systemization of application security hardening. The security solutions are woven into GIMPLE representations in a systematic way, eliminating the need for manual hardening that might generate a considerable number of errors. To achieve this goal, we present a formal specification for GIMPLE weaving and the implementation strategies of the proposed weaving semantics. Syntax for a common aspect-oriented language that is abstract and multi-language support together with syntax for a core set for GIMPLE constructs are presented to express the weaving semantics. GIMPLE weaving accompanied by a common aspect-oriented language (1) allows security experts providing security solutions using this common language, (2) lets developers focus on the main functionality of programs by relieving them from the burden of security issues, (3) unifies the matching and the weaving processes for mainstream languages, and (4) facilitates introducing new security features in AOP languages. We handle the correctness and the completeness of GIMPLE weaving in two different ways. In the first approach, we prove them according to the rules and algorithms provided in this paper. In the second approach, we accommodate Kniesel's discipline that ensures that security solutions specified by our approach are applied at all and only the required points in source code, taking into consideration weaving interactions and interferences. Finally, we explore the viability and the relevance of our propositions by applying the defined approach for systematic security hardening to develop case studies.     

A pointcut-based coverage analysis approach for aspect-oriented programs

Aspect-oriented programming (AOP) is a promising technology that supports separation of crosscutting concerns (i.e., functionality that tends to be tangled with, and scattered through the rest of the system). In AOP, a method-like construct named advice is applied to join points in the system through a special construct named pointcut. This mechanism supports the modularization of crosscutting behavior; however, since the added interactions are not explicit in the source code, it is hard to ensure their correctness. To tackle this problem, this paper presents a rigorous coverage analysis approach to ensure exercising the logic of each advice - statements, branches, and def-use pairs - at each affected join point. To make this analysis possible, a structural model based on Java bytecode - called PointCut-based Def-Use Graph (PCDU) - is proposed, along with three integration testing criteria. Theoretical, empirical, and exploratory studies involving 12 aspect-oriented programs and several fault examples present evidence of the feasibility and effectiveness of the proposed approach.     

A wrapping approach for migrating legacy system interactive functionalities to Service Oriented Architectures

Software systems modernisation using Service Oriented Architectures (SOAs) and Web Services represents a valuable option for extending the lifetime of mission-critical legacy systems.This paper presents a black-box modernisation approach for exposing interactive functionalities of legacy systems as Services. The problem of transforming the original user interface of the system into the request/response interface of a SOA is solved by a wrapper that is able to interact with the system on behalf of the user. The wrapper behaviour is defined in the form of Finite State Machines retrievable by black-box reverse engineering of the human-computer interface.The paper describes our wrapper-based migration process and discusses the results of case studies showing process effectiveness and quality of resulting services.     

A language for high-level description of adaptive web systems

Adaptive Web systems (AWS) are Web-based systems that can adapt their features such as, presentation, content, and structure, based on users’ behaviour and preferences, device capabilities, and environment attributes. A framework was developed in our research group to provide the necessary components and protocols for the development of adaptive Web systems; however, there were several issues and shortcomings (e.g. low productivity, lack of verification mechanisms, etc.) in using the framework that inspired the development of a domain-specific language for the framework. This paper focuses on the proposal, design, and implementation of AWL, the Adaptive Web Language, which is used to develop adaptive Web systems within our framework. Not only does AWL address the existing issues in the framework, but it also offers mechanisms to increase software quality attributes, especially, reusability. An example application named PENS (a personalized e-News system) is explained and implemented in AWL. AWL has been designed based on the analysis of the adaptive Web domain, having taken into account the principles of reuse-based software engineering (product-lines), domain-specific languages, and aspect-oriented programming. Specially, a novel design decision, inspired by aspect-oriented programming paradigm, allows separate specification of presentation features in an application from its adaptation features. The AWL’s design decisions and their benefits are explained.     

An approach and tool for measurement of state variable based data-flow test coverage for aspect-oriented programs

ContextData-flow testing approaches have been used for procedural and object-oriented programs, and shown to be effective in detecting faults. However, few such approaches have been evaluated for aspect-oriented programs. In such programs, data-flow interactions can occur between base classes and aspects, which can affect the behavior of both. Faults resulting from such interactions are hard to detect unless the interactions are specifically targeted during testing.ObjectiveThis paper presents an approach and tool implementation for measuring data-flow coverage based on state variables defined in base classes or aspects in AspectJ programs. The paper also reports on an empirical study that compares the cost and effectiveness of data-flow test criteria that are based on state variables with two control-flow criteria.MethodEffectiveness of the criteria was evaluated for various fault types. Cost-effectiveness of test suites that cover all state variable definition-use associations (DUAs) was evaluated for three coverage levels: 100%, 90%, and 80%.ResultsThe effort needed to obtain a test case that achieves data-flow coverage is higher than the effort needed to obtain a test case that covers a block or a branch in an advised class. Covering certain data flow associations requires more effort than for other types of data flow associations. The data-flow test criteria based on state variables of a base-class are in general more effective than control-flow criteria.ConclusionsOverall, it is cost-effective to obtain test suites at the 90% coverage level of data-flow criteria.     

Measurement and defect modeling for a legacy software system

This paper analyzes the quality of a large-scale legacy software system using selected metrics. Quality measurements include defect information collected during product development and in-field operation. Other software metrics include measurements on various product and process attributes, including design, size, change, and complexity. Preliminary analyses revealed the high degree of skew in our data and a weak correlation between defects and software metrics. Tree-based models were then used to uncover relationships between defects and software metrics, and to identify high-defect modules together with their associated measurement characteristics. As results presented in tree forms are natural to the decision process and are easy to understand, tree-based modeling is shown to be suitable for change solicitation and useful in guiding remedial actions for quality improvement.The following are trademarks or service marks in the United States and/or other countries: IBM is a trademark of International Business Machines Corporation. REFINE and Software Refinery are trademarks of Reasoning Systems Inc. SAS is a trademark of the SAS Institute Inc. S-PLUS is a trademark of the Statistical Sciences, Inc.     

Using aspect orientation in legacy environments for reverse engineering using dynamic analysis—An industrial experience report

This paper reports on the challenges of using aspect-oriented programming (AOP) to aid in re-engineering a legacy C application. More specifically, we describe how AOP helps in the important reverse engineering step which typically precedes a re-engineering effort. We first present a comparison of the available AOP tools for legacy C code bases, and then argue on our choice of Aspicere, our own AOP implementation for C. Then, we report on Aspicere’s application in reverse engineering a legacy industrial software system and we show how we apply a dynamic analysis to regain insight into the system. AOP is used for instrumenting the system and for gathering the data. This approach works and is conceptually very clean, but comes with a major quid pro quo: integration of AOP tools with the build system proves an important issue. This leads to the question of how to reconcile the notion of modular reasoning within traditional build systems with a programming paradigm which breaks this notion.     

Applying agglomerative hierarchical clustering algorithms to component identification for legacy systems

Context

Component identification, the process of evolving legacy system into finely organized component-based software systems, is a critical part of software reengineering. Currently, many component identification approaches have been developed based on agglomerative hierarchical clustering algorithms. However, there is a lack of thorough investigation on which algorithm is appropriate for component identification.

Objective

This paper focuses on analyzing agglomerative hierarchical clustering algorithms in software reengineering, and then identifying their respective strengths and weaknesses in order to apply them effectively for future practical applications.

Method

A series of experiments were conducted for 18 clustering strategies combined according to various similarity measures, weighting schemes and linkage methods. Eleven subject systems with different application domains and source code sizes were used in the experiments. The component identification results are evaluated by the proposed size, coupling and cohesion criteria.

Results

The experimental results suggested that the employed similarity measures, weighting schemes and linkage methods can have various effects on component identification results with respect to the proposed size, coupling and cohesion criteria, so the hierarchical clustering algorithms produced quite different clustering results.

Conclusions

According to the experimental results, it can be concluded that it is difficult to produce perfectly satisfactory results for a given clustering algorithm. Nevertheless, these algorithms demonstrated varied capabilities to identify components with respect to the proposed size, coupling and cohesion criteria.     

A compiler-hardware approach to software protection for embedded systems

Because of their rapid growth in recent years, embedded systems present a new front in vulnerability and an attractive target for attackers. Their pervasive use, including sensors and mobile devices, makes it easier for an adversary to gain physical access to facilitate both attacks and reverse engineering of the system. This paper describes a system - CODESSEAL - for software protection and evaluates its overhead. CODESSEAL aims to protect embedded systems from attackers with enough expertise and resources to capture the device and attempt to manipulate not only software, but also hardware. The protection mechanism involves both a compiler-based software tool that instruments executables and an on-chip FPGA-based hardware component that provides run-time integrity and control flow checking on the executable code. The use of reconfigurable hardware allows CODESSEAL to provide such security services as confidentiality, integrity and program-flow protection in a platform-independent manner without requiring a redesign of the processor. Similarly, the compiler instrumentation hides the security details from software developers. Software and data protection techniques are presented for our system and a performance analysis is provided using cycle accurate simulation. Our experimental results show that protecting instructions and data with a high level of security can be achieved with low performance penalty, in most cases less than 10%.     

A unit test approach for database schema evolution

Context

The constant changes in today’s business requirements demand continuous database revisions. Hence, database structures, not unlike software applications, deteriorate during their lifespan and thus require refactoring in order to achieve a longer life span. Although unit tests support changes to application programs and refactoring, there is currently a lack of testing strategies for database schema evolution.

Objective

This work examines the challenges for database schema evolution and explores the possibility of using various testing strategies to assist with schema evolution. Specifically, the work proposes a novel unit test approach for the application code that accesses databases with the objective of proactively evaluating the code against the altered database.

Method

The approach was validated through the implementation of a testing framework in conjunction with a sample application and a relatively simple database schema. Although the database schema in this study was simple, it was nevertheless able to demonstrate the advantages of the proposed approach.

Results

After changes in the database schema, the proposed approach found all SELECT statements as well as the majority of other statements requiring modifications in the application code. Due to its efficiency with SELECT statements, the proposed approach is expected to be more successful with database warehouse applications where SELECT statements are dominant.

Conclusion

The unit test approach that accesses databases has proven to be successful in evaluating the application code against the evolved database. In particular, the approach is simple and straightforward to implement, which makes it easily adoptable in practice.     

A software integration approach for designing and assessing dependable embedded systems

Embedded systems increasingly entail complex issues of hardware-software (HW-SW) co-design. As the number and range of SW functional components typically exceed the finite HW resources, a common approach is that of resource sharing (i.e., the deployment of diverse SW functionalities onto the same HW resources). Consequently, to result in a meaningful co-design solution, one needs to factor the issues of processing capability, power, communication bandwidth, precedence relations, real-time deadlines, space, and cost. As SW functions of diverse criticality (e.g. brake control and infotainment functions) get integrated, an explicit integration requirement need is to carefully plan resource sharing such that faults in low-criticality functions do not affect higher-criticality functions.On this background, the main contribution of this paper is a dependability-driven framework that helps to conduct the integration of SW components onto HW resources such that the maintenance of system dependability over integration of diverse criticality components is assured by design.We first develop a clustering strategy for SW components into Fault Containment Modules (FCMs) such that error propagation via interaction is minimized. Subsequently, the rules of composition for FCMs with respect to error propagation are developed. To allocate the resulting FCMs to the existing HW resources we provide several heuristics, each optimizing particular attributes thereof. Further, a framework for assessing the goodness of the achieved HW-SW composition as a dependable embedded system is presented. Two new techniques for quantifying the goodness of the proposed mappings are introduced by examples, both based on a multi-criteria decision theoretic approach.     

A knowledge-based approach for multi-factory production systems

This paper investigates scheduling of jobs with deadlines across a serial multi-factory supply chain which involves minimizing sum of total tardiness and total transportation costs. Jobs can be transported among factories and can be delivered to the customer in batches which have limited capacity. The aim of this optimization problem is threefold: (1) determining the number of batches, (2) assigning jobs to batches, and (3) scheduling the batches production and delivery in each factory. The proposed problem formulated as a mixed-integer linear program. Then the model's performance is analyzed and evaluated through two examples. Moreover, a knowledge-based imperialistic competitive algorithm (KBICA) is also presented to find an approximate optimum solution for the problem. Computational experiments of the proposed problem investigate the efficiency of the method through different sizes of the test problems.     

Knowledge Discovery Metamodel-ISO/IEC 19506: A standard to modernize legacy systems

Legacy systems age over time as a consequence of uncontrolled maintenance, thus they must be evolved while its valuable embedded knowledge is preserved. Software modernization, and particularly Architecture-Driven Modernization, has become the best solution in the legacy systems’ evolution. ADM defines the Knowledge Discovery Metamodel specification, now being adopted as ISO/IEC 19506 by the International Standards Organization. The KDM metamodel allows to represent all the software artifacts recovered during reverse engineering techniques at different abstraction levels. This paper presents how to use KDM to modernize legacy systems, making them more agile, preserving the embedded business knowledge and reducing maintenance costs.     

Cell size determination in WCDMA systems using an evolutionary programming approach

This paper deals with the problem of the cell size determination in WCDMA-based mobile networks, in multiservice environments. The objective is to obtain the maximum cell size, given a set of services with their corresponding constraints, in terms of quality of service (QoS), binary rate, etc. To achieve this, we have to find the optimal services’ load factors which maximizes the cell radius of the system under traffic criteria. We apply an evolutionary programming algorithm to solve the problem, which codifies and evolves the services’ load factors. We have compared our approach with an existing algorithm in several multiservice scenarios, improving its solutions in terms of cell size.     

A scalable method for testing real-time systems

Real-time systems (RTSs) are used in different domains such as telephone switching systems, air traffic control systems and patient monitoring systems. The behavior of RTSs is time-sensitive; that is, RTSs interact with their environment with input and output events under time constraints. The violation of such time constraints is the main cause of the misbehavior of RTSs, and may result in severe damage to human lives and the environment [Mandrioli, D., Morasca, S., & Morzenti, A. 1995. ACM Transactions on Computer Systems, 13(4), 365–398]. To prevent failures in RTSs, we must verify that the implementation of an RTS is correct before its deployment. Testing is one of the formal techniques that can be used to achieve this goal. It consists of three main phases: test generation, test execution, and test results analysis. This paper presents a test case generation method for RTSs modeled as Timed Input Output Automata (TIOA). The approach is made in two steps. First, the TIOA describing the system being tested is sampled to construct a subautomaton, which is easily testable (i.e., easy to generate test cases from it). Then, the resulting subautomaton is traversed to generate test cases. Our method is scalable in the sense that it generates a small number of test cases even when the specifications are significant. Moreover, the test cases derived by our method are executable (i.e., they can be run on any error-free implementation of the system being tested).

A formal approach to reactive systems software: A telecommunications application in Esterel

Esterel is a formally-defined language designed for programming reactive systems; namely, those that maintain a permanent interaction with their environment. The AT&T 5ESS^® telephone switching system is an example of a reactive system. We describe an implementation in Esterel of one feature of a 5ESS switch; this implementation has been tested in the 5ESS switch simulator. Furthermore, it has been formally verified that this implementation satisfies some safety properties stated by 5ESS software development. Our experience indicates that Esterel is suitable for programming industrial-strength reactive systems, and affords significant advantages in software development over more traditional programming languages used in industrial settings.An earlier version of this paper appeared in the Proceedings of the Workshop on Industrial-Strength Formal Specification Techniques, Boca Raton, Florida, 1995.The author is currently supported by a Fulbright fellowship from Spain's Ministry of Science and Education. The work described here was performed while the author was visiting AT&T Bell Laboratories.     

自愈软件系统设计与实现方法

针对自愈软件系统功能层与自愈层交织带来的设计复杂性问题,提出系统横向模型驱动设计思想,给出一种以故障模型为中心的系统设计与实现方法。该方法能够将系统功能层与自愈层隔离,使它们的设计与实现相对独立,根据系统特点在不同阶段通过故障模型加以耦合,这种松耦合方式有利于降低系统整体设计的复杂性,提高可配置性、可重用性以及可维护性。通过一个具有自愈特性的捷联惯性导航系统仿真软件的设计与实现,验证了该设计思想与方法的可行性和有效性。