11602397
Compiling process algebraic specifications into timed automata
The authors present LTP (Language of Timed Processes), a process-algebra-based specification language, for the specification of real-time applications. In addition to timing requirements involving the execution time of individual computations, LTP can specify timing constraints that are associated with process descriptions: periodic constraints and sporadic constraints. Periodic processes (e.g. sensors) are usually time-driven; sporadic processes are usually event-driven. In LTP common real-time constraints such as delays, deadlines, and timeouts can be modeled conveniently. They specifically introduce a new construct for modeling periodic behavior, which is quite common in real-time applications. They validate LTP specifications by translating from LTP to a kind of timed automata that is amenable to well-known model checking techniques. Although the models of LTP specifications, commonly known as timed transition systems, are usually infinite because of the presence of time, the translation results in a finite representation by which automatic verification is possible.
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.
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.
15614662
Towards increasing web application productivity
In this paper we present and discuss a template/meta-data based partial code generation system supporting web application development. Seamlessly incorporating the recent top-notch technologies, the framework maximally exploits the capabilities of the underlying implementation technologies. Our approach primarily benefits the framework and code developers. In addition, the complete separation of data model, navigation model, and presentation model reflects on a more general conceptual process that would decouple the technique and methodology from its underlying technology choices. The decoupling between the generated code and the code that is necessarily added later on through other development pathways than the generator deals with the incremental changes and adaptations of the models in the face of an operational system, therefore further enhances the extensibility, maintainability, and reusability of the generated applications.
1871945
Specifications in software prototyping
Abstract We explore the use of software specifications for software prototyping. This paper describes a process model for software prototyping, and shows how specifications can be used to support such a process via a cellular mobile phone switch example.
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.
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.
2457108
An object-oriented real-time distributed simulation of cellular phone switching system
The cellular phone network is a distributed system which is composed of three kinds of subsystems, a mobile phone unit, a base site station and a MSC (mobile switching center). A class of cellular phone switching systems, was chosen as the system to be studied. SUN workstations and the UNIX operating system with X windows have been employed as the core of the development environment. The object-oriented (OO) paradigm and C++ were chosen to develop the simulation. UICCELL was developed as an object-oriented system for cellular phone switching real-time multitasking simulation. UICCELL has been fully implemented and is currently running on an Ethernet LAN. A central monitor is created on the screen to manipulate and monitor the simulator. The graphical user interface displays the configuration of UICCELL and the status of processors, channels, etc. The current implementation contains 60 classes and about 20,000 lines of C++ code.<<ETX>>
30575380
Modeling a real-time multitasking system in a timed PQ net
A system is described that integrates timed Petri nets and queueing networks to model complex, real-time systems. It includes a graphical modeling tool, called TPQN, a textual specification language, called TPQL, and a simulator, called TPQS. TPQN's capabilities are illustrated by a performance analysis of a real-time, multitasking scheduler that had been previously implemented on top of SunOS on a Sun-3 workstation. A simulation package has been developed for TPQN that allows the behavior of various complicated systems under a designated queueing network topology to be studied before the system is implemented.<<ETX>>
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>>
18983514
Sequence Learning in Mobile Robots Using Avalanche Neural Networks
This paper describes the implementation of a neural network for sequence learning that is based on a neurocomputational theory of learning. The network is implemented on a physical mobile robot in order to learn to reproduce sequences of motor actions. At the onset of a conditioned stimulus the robot is presented with a sequence of visual stimuli that produce reactive motor actions of different duration. Initial results show that after learning the robot can approximate the motor sequence with no visual stimulation.