15990035
Content-based retransmission for 3-D wavelet video streaming on the Internet
Improving the QoS of video streaming with packet loss is a challenging topic of research. In this paper, we propose a novel content-based retransmission scheme to address this issue. The basic idea is to jointly consider the packets' contents and the channel conditions to optimize QoS. The goal is to deliver the best quality of video possible under the same channel condition. Using the proposed retransmission scheme, we have designed a 3D wavelet video streaming system. Simulation results show that the content-based retransmission can improve the video quality by more than 2 dB compared with the existing non-content-based delay-constrained retransmission when the channel loss rate is high.
2048896
The Use of Parallel Processing to Achieve Decentralized Control of a Segmented Reflector Telescope
7872291
Sensors and Actuators in TCOZ
Timed Communicating Object Z (TCOZ) combines Object-Z's strengths in modeling complex data and algorithms with Timed CSP's strengths in modeling real-time concurrency. TCOZ inherits CSP's channel-based communication mechanism, in which messages represent discrete synchronisations between processes. The purpose of most control systems is to observe and control analog components. In such cases, the interface between the control system and the controlled systems cannot be satisfactorily described using the channel mechanism. In order to address this problem, TCOZ is extended with continuous-function interface mechanisms inspired by process control theory, the sensor and the actuator. The utility of these new mechanisms is demonstrated through their application to the design of an automobile cruise control system.
18879642
A Component Framework for Resource Management Systems
Resource management is a complex process in many business organizations. Current solutions are typically in a case-by-case manner. In this paper, we present a general component framework for resource management such that different applications can be instantiated from the framework.
10543361
Commutability of Design Pattern Instantiation and Integration
Design patterns capture expert design experience in generic design structure and behavior. A design pattern needs to be instantiated before using. It can be integrated with other patterns as well. The instantiation and integration operations are two important operations when a designer uses a design pattern in a particular application. In this paper, we investigate the commutability of these two operations based on our formal specification framework. We provide rigorous proofs on the conditions when the order of these two operations does not matter. Our results enable the software designers to choose their design processes with assurance of their equivalence.
3121999
A pattern-based approach to structural design composition
This paper describes an approach to component-based software engineering based on a formal description of design patterns. The architectural design information, captured by design patterns, is made explicit and represented in a declarative way, being packaged into tangible artifacts as building block design components in the development process. These design component descriptions can be instantiated, adapted, assembled, implemented, and maintained. Furthermore, we can use these representations to reason about properties related to the combination of design components. We illustrate the utility of our approach through a case study involving various design patterns.
15362726
State, event, time and diagram in system modeling
The design of complex systems requires powerful mechanisms for modeling state, concurrent events, and real-time behavior; as well as for visualising and structuring systems in order to control complexity. Methods integration has become a recent research trend in software specification and design. In the graphical area, many object-oriented methods have merged into one, the Unified Modeling Language (UML) which combines various diagrammatic modeling techniques to model static and dynamic aspects of software systems. Although traditional formal methods have not scale-up well, new integrated formal methods show great promise. This tutorial will present the state of the art in formal modeling techniques (state-based Object-Z and event-based Timed CSP), their integration (TCOZ), and transformation techniques from the integrated formalism to UML diagrams. An XML web environment for projecting integrated formal models to UML diagrams will also be demonstrated.