17140893
An Aspect-Oriented Approach to Resource Composition in Petri net-based Software Architectural Models
Petri net has been widely used for modeling software systems due to its mathematical soundness and support of various tools. In many cases, performance-related analyses of Petri net for a software system need to consider the resource limitations caused by a specific platform. In terms of aspect-oriented approach, the interference of various resources scattered across a software system can be regarded as a specific concern that is only necessary during its performance-related analysis process. To capture the interactions of resources within the Petri net-based software architectural model, we propose an aspect-oriented resource composition model and the XML-based representation language called the resource extension markup language (ReML) for its description. In our approach, one or more resource composition models can be developed and described in ReML separately from the development of base software architectural models. Through the weaving process, a resource composition model can be applied to extend several Petri net-based software architectural models. The resource weaver generates an augmented Petri net used for analyzing performance characteristics of the extended software architectural model with resource interactions. Our aspect-oriented approach facilitates selecting an optimal or superior resource composition model for a software architectural model, and vice versa, which is illustrated using two exemplary server models
215862843
Genetic Algorithms for Project Management
The scheduling of tasks and the allocation of resource in medium to large-scale development projects is an extremely hard problem and is one of the principal challenges of project management due to...
18643244
An Empirical Performance Study on PSIM
It is well known that errors caught in the early stages of system development life cycle greatly helped reduce the expense for later error fixing and mitigate risks and complications. Performance analysis is one of the methods to ensure satisfactory system performance that can avoid redesign and patch in the later stage of system development when performance problems emerge. Much work has been done to address such concerns collectively known as the 'performance engineering' problem. However, a comprehensive method is still needed to provide an end-to-end support for performance evaluation on software architecture design. Automated tools to support the method must be developed, and its validation must be carefully planned and conducted. In response to this need, we propose our approach, PSIM (performance simulation and modeling). PSIM is a performance simulation and modeling tool that integrated performance properties into software architecture specifications expressed in several major UML diagrams. PSIM models can be transformed into Colored GSPN (colored generalized stochastic Petri nets) via an automated tool. As a result, the Colored GSPN models can be simulated to perform model-based performance evaluation. In this paper PSIM is first briefly reviewed and illustrated through modeling a web-based electronic conferencing system, called M-Net, to derive performance metrics. We then conduct runtime performance testing to the implementation of M-Net and compare the simulation results against the runtime testing data. PSIM is shown to be effective in predicting system performance and in identifying system performance bottlenecks through this experimentation.
8941164
Supporting agent-based distributed software development through modeling and simulation
In today's software engineering environment, it is becoming increasingly commonplace for team members and stakeholders to be distributed in multiple locations and time zones. Under these circumstances, the coordination of software development activities becomes increasingly more complex. One solution uses mobile agent-based tools to support collaborative software engineering tasks, such as requirements management. Despite the fact that development and validation of such tools would be facilitated by the use of modeling and simulation, very little work relating formal methods to agent-based system development has been performed. This paper therefore presents a hierarchical colored Petri Net (CPN) model as a formal framework for agent-based distributed software development, and demonstrates its usefulness by applying the framework to the development of a requirements management system.
11560314
Distributed systems design using function-class decomposition with aspects
Object-oriented methods are known for their capabilities to encapsulate and manage core concerns of complex software systems. However, they are inadequate in discerning and separating a variety of other cross-cutting concerns. In particular, for distributed systems, a number of important concerns such as synchronization, logging, and security, should be sufficiently treated in the design phase of the software lifecycle in order to ensure high system quality. Often these concerns tend to be overlooked at the design level and consequently scattered across multiple system modules during implementation. Consequently it becomes difficult to connect the set of requirements with the system structure, thus system traceability is reduced. This paper proposes an extension to the function-class decomposition (FCD) method, that is a hybrid method of structured analysis and OO approach, by integrating the concepts of "aspect". "Aspect" is an abstraction mechanism that emerged in recent years from the aspect-oriented programming (AOP) community. This extended method supports separation of functional and non-functional concerns by maintaining two primary views (function-class view and aspect view) at the design stage, and demonstrates the iterative process by applying it to the development of an example system called M-Net that is an Internet-based real-time distributed conferencing system.
10317156
A research on Collaboration Net
We present research on computer-supported cooperative work by introducing an approach to the multimedia based net-centric conference environment-Collaboration Net. Some basic definitions of the distributed Web-based meeting are provided, and the properties of this kind of collaboration are given. We explain problems associated with the well-known yet old-fashioned parliamentary procedure, Robert's Rules of Order, which must be formally modeled and adapted to the modern net-centric virtual conference where time synchronism is hard to enforce. A prototype of our Web-browser based approach to developing the Collaboration Net is also briefly presented. Finally, research challenges in this area are highlighted.
17968637
Robust localization of multiple events in sensor networks
Localization of events is a canonical problem for sensor networks, especially for applications such as intrusion detection or neighborhood monitoring. We employ a general sensor model which models various types of sensor nodes. However, traditional triangulation method will be unsolvable when the sensor nodes are positioned on a line. To overcome such ill-conditioned cases, we can use MAP or MMSE methods to estimate event locations. Moreover, to locate multiple simultaneous events and overcome the ill-conditioned case when the sensor nodes are collinear, we need to solve a system of nonlinear equations. We propose a novel method which solves this system of nonlinear equations and multiple-event locations can be found. Experiments and error analysis of the method demonstrate the performance of our methods
14942562
Improving hallway navigation in mobile robots with sensor habituation
Habituation is a form of non-associative learning observed in a variety of species of animals. Arguably, it is the simplest form of learning. Nonetheless, the ability to habituate to certain stimuli implies plastic neural systems and adaptive behaviors. This article describes how computational models of habituation can be applied to real robots. In particular, we discuss the problem of the oscillatory movements observed when a Khepera robot navigates through narrow hallways. Results show that habituation to the proximity of the walls can lead to smoother navigation. Habituation to sensory stimulation to the sides of the robot does not interfere with the robot's ability to turn at dead ends and to avoid obstacles outside the hallway. This work shows that simple biological mechanisms of learning can be adapted to achieve better performance in real mobile robots.
35252145
Fast eigenspace decomposition of correlated images
We present a computationally efficient algorithm for the eigenspace decomposition of correlated images. Our approach is motivated by the fact that for a planar rotation of a two-dimensional (2-D) image, analytical expressions can be given for the eigendecomposition, based on the theory of circulant matrices. These analytical expressions turn out to be good first approximations of the eigendecomposition, even for three-dimensional (3-D) objects rotated about a single axis. In addition, the theory of circulant matrices yields good approximations to the eigendecomposition for images that result when objects are translated and scaled. We use these observations to automatically determine the dimension of the subspace required to represent an image with a guaranteed user-specified accuracy, as well as to quickly compute a basis for the subspace. Examples show that the algorithm performs very well on a number of test cases ranging from images of 3-D objects rotated about a single axis to arbitrary video sequences.
12945067
A Fast Search Algorithm for Vector Quantization
285,641. British Celanese, Ltd., and Olpin, H. C. Feb. 9, 1927. Samples furnished. Anthraquinone derivatives.-Sulphuric esters of anthraquinonylamino alcohols, which are dyestuffs for organic substitution products of cellulose, e.g. cellulose esters and ethers, and for animal fibres, are made by treating the corresponding alcohols with sulphuric acid or oleum; or by the action of sulphuric esters of aminoalcohols on leuco oxyanthraquinones, e.g. the leuco compounds of 1-oxy-, 1 : 4-dioxy-, 1 : 4 : 5- trioxy or 1 : 4 : 5 : 8-tetraoxy-anthraquinone, followed by oxidation of the leuco body; or by replacement of chlor, nitro, methoxy &c. groups by treatment with sulphuric esters of aminoalcohols, e.g. #-aminoethyl alcohol. The anthraquinonylamino alcohols, for treatment with sulphuric acid or oleum, may be obtained by treating amino or mono-substituted amino derivatives of anthraquinone or substituted anthraquinones with halohydrins, e.g. ethylene, propylene or glyceryl chlorhydrins, epichlorhydrin, or chlorbutylene glycol, or with alkylene oxides, e.g. ethylene or propylene oxide, or with oxyaldehydes or ketones, or by replacement of chlor, nitro, hydroxy, methoxy &c. groups by treatment with an amino alcohol. The sulphuric esters of 1-#-oxyethylamino-, 1-#-oxyethylamino-2 (and 4)- methyl-, 1-#-oxyethylamino-4-oxy (and amino)-, 1-#-oxyethylamino-2-brom-4-amino-, and 1 : 4- and 1: 5-di-#-oxyethylamino-anthraquinones are specified.
9710130
A specification language for real-time distributed systems
The authors introduce a design specification method, extended modified Petri nets (EMPN), and its description language (EMPNDL). The specification is based on a stochastic Petri-net model and is suitable for modeling real-time distributed systems. The syntax of the language is formally described in BNF grammar while the semantics is based on that for stochastic Petric nets. In addition to the modeling capability of EMPN and EMPNDL, methods for verification and validation of such systems are also discussed. EMPN and EMPNDL have been extensively used to the specification of a prototype switching system, UICPBX. Based on the presented formulation, verification and validation of UICPBX can be automated to a great extent.<<ETX>>