Modern enterprises are irreversibly dependent on large-scale, adaptive, component-based information systems whose complexity frequently exceeds current engineering capabilities for intellectual control, resulting in p...
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(纸本)0769514359
Modern enterprises are irreversibly dependent on large-scale, adaptive, component-based information systems whose complexity frequently exceeds current engineering capabilities for intellectual control, resulting in persistent difficulties in system development, management, and evolution. We propose an innovative framework of engineering representation and reasoning methods for developing these complex systems: the flow-service-quality (FSQ) framework. In dynamic network information systems with constantly varying function and usage, workflows and their corresponding traces of system services act as stable foundations for functional and non functional (quality attribute) specification, design, and operational control. Our objective is to provide theoretical foundations, language representations, and rigorous yet practical unified engineering methods to represent and reason about system flows as essential artifacts of system specification, design, and operation.
Much of the software we use for everyday purposes incorporates elements developed and maintained by someone other than the developer. These elements include not only code and databases but also dynamic data feeds from...
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Much of the software we use for everyday purposes incorporates elements developed and maintained by someone other than the developer. These elements include not only code and databases but also dynamic data feeds from online data sources. Although everyday software is not mission critical, it must be dependable enough for practical use. This is limited by the dependability of the incorporated elements. It is particularly difficult to evaluate the dependability of dynamic data feeds, because they may be changed by their proprietors as they are used. Further, the specifications of these data feeds are often even sketchier than the specifications of software components. We demonstrate a method of inferring invariants about the normal behavior of dynamic data feeds. We use these invariants as proxies for specifications to perform on-going detection of anomalies in the data feed. We show the feasibility of our approach and demonstrate its usefulness for semantic anomaly detection: identifying occasions when a dynamic data feed is delivering unreasonable values, even though its behavior may be superficially acceptable (i.e., it is delivering parsable results in a timely fashion).
Coordination programming helps to separate concerns in the programming of the coordination activities in complex applications software. It separates the development, verification, maintenance, and reuse of the coordin...
Coordination programming helps to separate concerns in the programming of the coordination activities in complex applications software. It separates the development, verification, maintenance, and reuse of the coordination and communication protocols, from the development of the rest of the application; coincidentally making these entities into standalone products. The IWIM coordination model is briefly reviewed, and a formal automata theoretic version of the model is developed, capturing the essentials of the framework in a fibration based approach. Specifically, families of worker automata have their communication governed by a state of a manager automaton, whose transitions correspond to reconfigurations.
In response to the need to define the academic requirements for licensing professional engineers in Canada, the Canadian engineering Qualifications Board formed a committee whose mandate was to define the core and sup...
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In response to the need to define the academic requirements for licensing professional engineers in Canada, the Canadian engineering Qualifications Board formed a committee whose mandate was to define the core and supplemental bodies of knowledge for softwareengineering. Some of the issues and the outcome of the softwareengineering committee's deliberations are presented in this paper. After examining a number of inputs including national and provincial examination syllabi and curricula of accredited softwareengineering programs in Canada, a number of core topic areas were defined. These are: discrete mathematics, data structures and algorithms, software development (includes softwareengineering process, requirements design, construction, testing, maintenance, and configuration management), system reliability and safety, digital systems, computer architecture, operating systems, file and database, and systems and control. these topics generally match well with the existing examination syllabi and curricula. the supplemental areas are less well-defined and include depth in core subjects, depth in areas of specialization, and breadth in application domains.
Star queries are the most prevalent kind of queries in data warehousing, OLAP and business intelligence applications. Thus, there is an imperative need for efficiently processing star queries. To this end, a new class...
Star queries are the most prevalent kind of queries in data warehousing, OLAP and business intelligence applications. Thus, there is an imperative need for efficiently processing star queries. To this end, a new class of fact table organizations has emerged that exploits path-based surrogate keys in order to hierarchically cluster the fact table data of a star schema [DRSN98, MRB99, KS01]. In the context of these new organizations, star query processing changes radically. In this paper, we present a complete abstract processing plan that captures all the necessary steps in evaluating such queries over hierarchically clustered fact tables. Furthermore, we present optimizations for surrogate key processing and a novel early grouping transformation for grouping on the dimension hierarchies. Our algorithms have been already implemented in a commercial relational database management system (RDBMS) and the experimental evaluation, as well as customer feedback, indicates speedups of orders of magnitude for typical star queries in real world applications.
As software agents get more sophisticated, it becomes difficult to understand and model such systems. This paper contends that all developers bring to the task of development some implicit or explicit assumptions of t...
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As software agents get more sophisticated, it becomes difficult to understand and model such systems. This paper contends that all developers bring to the task of development some implicit or explicit assumptions of the agent communication pattern. This issue is not readily addressed in current literature and represents a gap in knowledge. For this purpose, a generic pattern of inter-agent communication is introduced and discussed in this paper. For better understanding and modelling of agent-based e-commerce systems, the semiotic approach and the DEMO transaction concept are briefly introduced. It is shown that the semiotic approach offers a unifying framework for identifying the roles of agents, the responsible human agents and the right/constraints associated with each role. The DEMO transaction concept is applied to model the communicative interaction between agents.
We are exploring the enhancement of models of agent behaviour with more "human-like" decision making strategies than are presently available. Our motivation is to build multi-agent based simulations of human...
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Scalable simulation in a cluster computing environment depends on effective mechanisms for load balancing. This paper presents an object-oriented software architecture and specifies communication protocols which suppo...
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This paper describes an experimental study in the use of a composable proxy framework to improve the quality of interactive audio streams delivered to mobile hosts. Two forward error correction (FEC) proxylets are dev...
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