DEVELOPMENT OF A MODIFIED METHOD OF NETWORK TRAFFIC FORMING

Based on the analysis of the statistical characteristics of heterogeneous network traffic of "Quadruple Play" mobile subscribers, it is shown that it cannot be represented by Poisson or Erlang distributions. It is shown that for such similar traffic, the rate of growth of the required buffer volume increases as the Hurst parameter increases. A method of adaptive traffic formation using the control of the length of intervals of the intensity of the arrival of data packets has been developed. Congestion management is carried out by changing the frequency of the marker generator (GM) on the basis of the results of forecasting the required bandwidth of the system and the required buffer size. The shaper adapts to changes in the length and instantaneous intensity of packet input in real-time

SDL Constructions of FIFO, LIFO and Absolute Contractors

Abstract — Despite all the recent advances in the mathematical theories for constructing optical queues by optical Switches and fiber Delay Lines (SDL), there are still many problems that need to be resolved. In this paper, we tackle the following problems: (i) is it possible to construct optical queues with switches of arbitrary sizes? (ii) is there a general theory that unifies many constructions of optical queues with known packet delays? and (iii) under what conditions can a concatenation of optical queues allow overtaking? For the first problem, we propose a new class of optical memory cells that can be made by switches of arbitrary sizes. Moreover, we propose the generalized C-transform for routing packets through such optical memory cells. For the second problem, we introduce a new class of optical queues, including FIFO, LIFO and absolute contractors. We show that both linear compressors in [13] and FIFO multiplexers (with multiple inputs) in [5], [7] are special cases of contractors. An interesting finding is that overtaking can occur in LIFO and absolute contractors. I

SDL Constructions of FIFO, LIFO and Absolute Contractors

[[abstract]]©2009 IEEE-Despite all the recent advances in the mathematical theories for constructing optical queues by optical Switches and fiber Delay Lines (SDL), there are still many problems that need to be resolved. In this paper, we tackle the following problems: (i) is it possible to construct optical queues with switches of arbitrary sizes? (ii) is there a general theory that unifies many constructions of optical queues with known packet delays? and (iii) under what conditions can a concatenation of optical queues allow overtaking? For the first problem, we propose a new class of optical memory cells that can be made by switches of arbitrary sizes. Moreover, we propose the generalized C -transform for routing packets through such optical memory cells. For the second problem, we introduce a new class of optical queues, including FIFO, LIFO and absolute contractors. We show that both linear compressors in [13] and FIFO multiplexers (with multiple inputs) in [5], [7] are special cases of contractors. An interesting finding is that overtaking can occur in LIFO and absolute contractors.[[department]]資訊工程學

Distributed systems : architecture-driven specification using extended LOTOS

The thesis uses the LOTOS language (ISO International Standard ISO 8807) as a basis for the formal specification of distributed systems. Contributions are made to two key research areas: architecture-driven specification and LOTOS language extensions. The notion of architecture-driven specification is to guide the specification process by providing a reference-base of pre-defined domain-specific components. The thesis builds an infra-structure of architectural elements, and provides Extended LOTOS (XL) definitions of these elements. The thesis develops Extended LOTOS (XI.) for the specification of distributed systems. XL- is LOTOS enhanced with features for the formal specification of quantitative timing. probabilistic and priority requirements. For distributed systems, the specification of these ‘performance’ requirements, ran be as important as the specification of the associated functional requirements. To support quantitative timing features, the XL semantics define a global, discrete clock which can be used both to force events to occur at specific times, and to measure Intervals between event occurrences. XL introduces time policy operators ASAP (as soon as possible’ corresponding to “maximal progress semantics") and ALAP (late as possible'). Special internal transitions are introduced in XL semantics for the specification of probability, Conformance relations based on a notion of probabilization, together with a testing framework, are defined to support reasoning about probabilistic XL specifications. Priority within the XL semantics ensures that permitted events with the highest priority weighting of their class are allowed first. Both functional and performance specification play important roles in CIM (Computer Integrated Manufacturing) systems. The thesis uses a CIM system known as the CIM- OSA lntegrating Infrastructure as a case study of architecture-driven specification using XL. The thesis thus constitutes a step in the evolution of distributed system specification methods that have both an architectural basis and a formal basis

Factors Influencing Customer Satisfaction towards E-shopping in Malaysia

Online shopping or e-shopping has changed the world of business and quite a few people have decided to work with these features. What their primary concerns precisely and the responses from the globalisation are the competency of incorporation while doing their businesses. E-shopping has also increased substantially in Malaysia in recent years. The rapid increase in the e-commerce industry in Malaysia has created the demand to emphasize on how to increase customer satisfaction while operating in the e-retailing environment. It is very important that customers are satisfied with the website, or else, they would not return. Therefore, a crucial fact to look into is that companies must ensure that their customers are satisfied with their purchases that are really essential from the ecommerce’s point of view. With is in mind, this study aimed at investigating customer satisfaction towards e-shopping in Malaysia. A total of 400 questionnaires were distributed among students randomly selected from various public and private universities located within Klang valley area. Total 369 questionnaires were returned, out of which 341 questionnaires were found usable for further analysis. Finally, SEM was employed to test the hypotheses. This study found that customer satisfaction towards e-shopping in Malaysia is to a great extent influenced by ease of use, trust, design of the website, online security and e-service quality. Finally, recommendations and future study direction is provided. Keywords: E-shopping, Customer satisfaction, Trust, Online security, E-service quality, Malaysia