Management of performance requirements for information systems

The management of performance requirements is a major challenge for information systems as well as other software systems. This is because performance requirements can have a global impact on the target system. In addition, there are interactions and trade-offs among performance requirements, other nonfunctional requirements (NFRs), and the numerous alternatives for the target system. To provide a systematic approach to managing performance requirements, this paper presents a performance requirements framework (PeRF). It integrates and catalogues a variety of kinds of knowledge of information systems and performance. These include: performance concepts, software performance engineering principles for building performance into systems, and information systems development knowledge. In addition, layered structures organize performance knowledge and the development process. All this knowledge is represented using an existing goal-oriented approach, the “NFR framework”, which offers a developer-directed graphical treatment for stating NFRs, analyzing and interrelating them, and determining the impact of decisions upon NFRs. This approach allows customized solutions to be built, taking into account the characteristics of the particular domain. The use of PeRF in managing performance requirements is illustrated in a study of performance requirements and other NFRs for a university student record system. This paper concludes with a summary of other studies of information systems, tool support and directions for future work     

Security Attack Testing (SAT)—testing the security of information systems at design time

For the last few years a considerable number of efforts have been devoted into integrating security issues into information systems development practices. This has led to a number of languages, methods, methodologies and techniques for considering security issues during the developmental stages of an information system. However, these approaches mainly focus on security requirements elicitation, analysis and design issues and neglect testing. This paper presents the Security Attack Testing (SAT) approach, a novel scenario-based approach that tests the security of an information system at the design time. The approach is illustrated with the aid of a real-life case study involving the development of a health and social care information system.     

Implementing information systems with project teams using ethnographic-action research

Architecture, engineering, and construction (AEC) projects are characterized by a large variation in requirements and work routines. Therefore, it is difficult to develop and implement information systems to support projects. To address these challenges, this paper presents a project-centric research and development methodology that combines ethnographic observation of practitioners working in local project organizations to understand their local requirements and the iterative improvement of information systems directly on projects in small action research implementation cycles. The paper shows the practical feasibility of the theoretical methodology using cases from AEC projects in North America and Europe. The cases provide evidence that ethnographic-action research is well suited to support the development and implementation of information systems. In particular, the paper shows that the method enabled researchers on the cases to identify specific problems on AEC projects and, additionally, helped these researchers to adapt information systems accordingly in close collaboration with the practitioners working on these projects.     

A relational framework for smart information delivery manual (IDM) specifications

This study proposes a relational framework for standardized machine-applicable, readable, and transferable (smart) information delivery manual (IDM) specifications. As the demand for projects using building information modeling (BIM) increases, there is a more acute awareness and need for clearly defined information requirements to support the BIM projects. The ISO 29481-1 IDM standard defines how to specify exchange requirements (ERs) and their use cases (UCs) using a process map (PM). However, IDM specifications are currently not easily sharable or reusable due to the lack of a commonly accepted standard data schema. This study overcomes this problem by identifying definitions and relationships of IDM components to develop the relational framework for an IDM data schema. An extensive review of existing IDM-related documents and standards, and iterative international meetings, were conducted by 46 international IDM experts from 16 countries. A consensus on the relational framework was then reached through three Delphi survey rounds. The formalized relational IDM framework lays a foundation for further developing an IDM data schema as an international standard.     

一种对混合系统进行高层系统需求分析并建立计算模型的方法

本文提出了一种对混合系统进行高层系统需求分析并建立计算模型的方法。文中不仅使用了场景和顺序图来提炼和描述混合系统中的离散事件通信,还为系统中的每个过程或构件提供了自动构建高层计算模型的方法。     

The application of information systems for the design and operation of flexible machining cells

The use of information systems in manufacturing applications has dramatically changed over the last few years. The design and implementation of somewhat dated relational databases has been replaced by the generation of information models, that can be simultaneously used for the development of information systems and satisfy their integration requirements. Over the last ten years the authors have been involved in a series of research programmes focusing on the design and operation of flexible machining cells. The use of information systems has been a central theme and the enabling technology to achieve a number of novel design concepts and operational strategies for such cells. The initial research was based on the utilization of relational databases to integrate a variety of modelling and design tools. However, the additional effort required to integrate such databases to manufacturing software tools, in the form of developing file translators, information gateways and interfac es, has made the authors adopt a new approach. With this approach the information requirements are represented in a neutral format within a data model, using a formal data specification language developed by the Standards for the Exchange of Product (STEP) committee. This paper describes these changes in the design and implementation of information systems in manufacturing applications, and provides an initial view of future research requirements.     

Browsing a document collection represented in two- and three-dimensional virtual information space

This paper reports a study of information retrieval performance using an interface in which documents were represented by objects in a virtual environment. Spatial location was determined by semantic content, with inter-object distance representing semantic similarity of documents. The quality of spatial-semantic mapping was manipulated as was the number of dimensions (two versus three) in which document nodes were arranged. Participants were required to browse the information space and identify all documents relevant to a specified topic. Results indicated that participants were able to use three-dimensional spatial mapping of semantic information to facilitate task performance, with performance being better when the quality of the mapping was higher. Strategy differences were identified, with participants adopting a more ‘exhaustive’ approach when searching two-dimensional node arrangements, and a more ‘focused’ approach for three-dimensional arrangements. Cognitive ability was not strongly associated with task performance, but participants of relatively lower cognitive ability tended to out-perform those of higher cognitive ability in three-dimensional conditions. Possible reasons for these findings are discussed.     

Efficient secure data publishing algorithms for supporting information sharing

Many data sharing applications require that publishing data should protect sensitive information pertaining to individuals, such as diseases of patients, the credit rating of a customer, and the salary of an employee. Meanwhile, certain information is required to be published. In this paper, we consider data-publishing applications where the publisher specifies both sensitive information and shared information. An adversary can infer the real value of a sensitive entry with a high confidence by using publishing data. The goal is to protect sensitive information in the presence of data inference using derived association rules on publishing data. We formulate the inference attack framework, and develop complexity results. We show that computing a safe partial table is an NP-hard problem. We classify the general problem into subcases based on the requirements of publishing information, and propose algorithms for finding a safe partial table to publish. We have conducted an empirical study to evaluate these algorithms on real data. The test results show that the proposed algorithms can produce approximate maximal published data and improve the performance of existing algorithms. Supported by the Program for New Century Excellent Talents in Universities (Grant No. NCET-06-0290), the National Natural Science Foundation of China (Grant Nos. 60828004, 60503036), and the Fok Ying Tong Education Foundation Award (Grant No. 104027)     

The value of information in information analysis

Information Requirements Analysis deals with defining the information needed for managerial purposes. It is considered as the first step of analysis in the development of an information system. This paper ties information requirements analysis with information evaluation. It is asserted that it is insufficient to simply find “needed” information items but also that such items should be evaluated in terms of their benefit.Three approaches to information evaluation are considered — realistic, normative and subjective. It is asserted that the normative approach may sometimes be applied in lower organizational levels, while at higher levels subjective evaluation is used. Some examples are discussed in this context. Finally, we discuss some procedures for applying evaluation in information analysis.     

Scalable Distributed Sensor Fault Diagnosis for Smart Buildings

The enormous energy use of the building sector and the requirements for indoor living quality that aim to improve occupants’ productivity and health, prioritize Smart Buildings as an emerging technology. The Heating, Ventilation and Air-Conditioning (HVAC) system is considered one of the most critical and essential parts in buildings since it consumes the largest amount of energy and is responsible for humans comfort. Due to the intermittent operation of HVAC systems, faults are more likely to occur, possibly increasing eventually building’s energy consumption and/or downgrading indoor living quality. The complexity and large scale nature of HVAC systems complicate the diagnosis of faults in a centralized framework. This paper presents a distributed intelligent fault diagnosis algorithm for detecting and isolating multiple sensor faults in large-scale HVAC systems. Modeling the HVAC system as a network of interconnected subsystems allows the design of a set of distributed sensor fault diagnosis agents capable of isolating multiple sensor faults by applying a combinatorial decision logic and diagnostic reasoning. The performance of the proposed method is investigated with respect to robustness, fault detectability and scalability. Simulations are used to illustrate the effectiveness of the proposed method in the presence of multiple sensor faults applied to a 83-zone HVAC system and to evaluate the sensitivity of the method with respect to sensor noise variance.      

Protection from reconnaissance for establishing information security systems

ABSTRACT

The paper presents a generalized method for improving security of information systems based on protection of the systems from reconnaissance by adversaries. Attacks carried out by exploiting almost all vulnerabilities require particular information about the architecture and operating algorithms of an information system. Obstructions to obtain that information also complicates carrying out attacks. Reconnaissance-protection methods can be utilized for establishing such systems (continuous change of attack surface). Practical implementation of the techniques demonstrated their high efficiency in reducing the risk of information resources to be cracked or compromised.     

A multi-objective evolutionary algorithm for an effective tuning of?fuzzy logic controllers in?heating, ventilating and air conditioning systems

This paper focuses on the use of multi-objective evolutionary algorithms to develop smartly tuned fuzzy logic controllers dedicated to the control of heating, ventilating and air conditioning systems, energy performance, stability and indoor comfort requirements. This problem presents some specific restrictions that make it very particular and complex because of the large time requirements needed to consider multiple criteria (which enlarge the solution search space) and the long computation time models required in each evaluation.     

Separate computation of alias information for reuse

Interprocedural data flow information is useful for many software testing and analysis techniques, including data flow testing, regression testing, program slicing and impact analysis. For programs with aliases, these testing and analysis techniques can yield invalid results, unless the data flow information accounts for aliasing effects. Recent research provides algorithms for performing interprocedural data flow analysis in the presence of aliases; however, these algorithms are expensive, and achieve precise results only on complete programs. This paper presents an algorithm for performing alias analysis on incomplete programs that lets individual software components such as library routines, subroutines or subsystems be independently analyzed. The paper also presents an algorithm for reusing the results of this separate analysis when the individual software components are linked with calling modules. Our algorithms let us analyze frequently used software components, such as library routines or classes, independently, and reuse the results of that analysis when analyzing calling programs, without incurring the expense of completely reanalyzing each calling program. Our algorithms also provide a way to analyze large systems incrementally     

Impact of information sharing in hierarchical decision-making framework in manufacturing supply chains

This paper presents a comprehensive framework for the analysis of the impact of information sharing in hierarchical decision-making in manufacturing supply chains. In this framework, the process plan selection and real-time resource allocation problems are formulated as hierarchical optimization problems, where problems at each level in the hierarchy are solved by separate multi-objective genetic algorithms. The considered multi-objective genetic algorithms generate near optimal solutions for NP-hard problems with less computational complexity. In this work, a four-level hierarchical decision structure is considered, where the decision levels are defined as enterprise level, shop level, cell level, and equipment level. Using this framework, the sources of information affecting the achievement of best possible decisions are then identified at each of these levels, and the extent of their effects from sharing them are analyzed in terms of the axis, degree and the content of information. The generality and validity of the proposed approach have been successfully tested for diverse manufacturing systems generated from a designed experiment.     

Enabling hierarchical dissemination of streams in content distribution networks

In streaming systems the content distribution network routes streams based on interests registered by the consuming entities. In hierarchical streaming, the dissemination is also predicated on the resolution of hierarchical dependencies between various streams. Entities specify explicit wildcards, in addition to the implicit ones in place, to further control the types of streams within a given hierarchy that should be routed to them. This paper presents an analysis and performance evaluation of three different algorithms for hierarchical streaming. In our evaluation of these algorithms we are especially interested in three factors: performance, ability to cope with flux, and memory consumption. Comprehensive benchmarks for these algorithms, in this paper, will enable system designers to harness the best algorithm that satisfies their hierarchical streaming requirements. Copyright © 2011 John Wiley & Sons, Ltd.     

Analysis of discrete-time piecewise affine and hybrid systems

In this paper, we present various algorithms both for stability and performance analysis of discrete-time piece-wise affine (PWA) systems. For stability, different classes of Lyapunov functions are considered and it is shown how to compute them through linear matrix inequalities that take into account the switching structure of the systems. We also show that the continuity of the Lyapunov function is not required in discrete time. Moreover, the tradeoff between the degree of conservativeness and computational requirements is discussed. Finally, by using arguments from the dissipativity theory for nonlinear systems, we generalize our approach to analyze the l₂-gain of PWA systems.