Catálogo de publicaciones - libros

Photoelastic fringe pattern for stress analysis is investigated by computer simulation. The first simulation is to separate isoclinics and isochromatics from photoelastic fringes of a circular disk under diametric compression by use of phase shift method. The second one is an analysis of photoelastic fringe patterns on perforated tensile plate with conformal mapping and measured data. The results of both simulations agree well with those of optical experiments.

In this paper, we analyzed the DRMA(Dynamic Reservation Multiple Access) protocol with Rayleigh fading, shadowing, and capture effect for the Broadband Wireless Access System. We consider the TDMA-based protocols, since these are based on the standard for IEEE 802.16 WMAN, IEEE 802.20 MBWA, and ETSI HIPERLAN/2. The results of analytical model will be apply the development of collision resolution algorithm, scheduling algorithm, and the dynamic change of system parameters.

Wireless Sensor Networks are the technology, in which various applications such as surveillance and information gathering are possible in the uncontrollable area of human. And numerous studies are being processed for the application of ubiquitous network environment. One of major issues in sensor network is the research for prolonging the lifetime of nodes through the use of various algorithms, suggested in the mac and routing layer. In this paper, aiming at reducing energy waste, caused by redundant transmission and receipt message, we propose the mac protocol using active signal and analysis performance through simulation.

In B2B EC area, the need for agent based system for desktop purchasing is increasing. To simulate agent based B2B e-Commerce, we model the b-cart based B2B agent framework. B-cart implies a buyer’s shopping cart which a buyer carries to the seller’s sites. The modeled system is designed to provide an effective architecture for employee’s direct desktop purchasing from external sellers’ e-marketplaces. In this paper, we propose the thirteen features of b-cart based agent system in B2B EC; Based on these features, we design the buying process, the system architecture, and message interfaces. We simulate the effect of the system by making a performance evaluation model. From this research we show a possibility and efficiency of the b-cart based agent system.

XML and metadata are used to represent the syntax, structure and semantic of information resources. But, various metadata sets, developed by independent organizations without any standards or guidelines, make it difficult to share XML encoded information resources. In this paper, we propose a framework named FSMI(Framework for Sharable Metadata Interoperability) to enable metadata level standardization and XML document sharing between applications. In FSMI, users of each system describe the difference between their XML schema and standard metadata registered in metadata registry, then they can interchange their XML documents with other system by resolving the difference. FSMI overcomes the limitations of other approaches with respect to exactness, flexibility and standardization, and provides an environment for business partners of different metadata to share XML encoded information resources.

As Service Oriented Architecture is expected to grow in the future e-business, web services are believed to be the ideal platform to integrate various business artifacts disparate platforms and systems. QoS(Quality of Service) of web services in terms of performance, reliability, and availability becomes the key issue when web services model complex and mission-critical applications. In this paper, we propose a simulation-based framework that enables web services to be composed based on their QoS properties. The proposed framework iteratively analyzes the QoS of the composite web services with multiple perspectives until the QoS requirements are met to various service users and providers.

In this paper we aim to incorporate wireless and mobile network with IEEE standard 1516 high level architecture (HLA). The proposed HLA federation not only provides seamless data communication but also supports the higher host interoperability for large-scale simulations. As the contemporary wireless LAN is concerned, it inherently sustains data communication suspension and intermittent message loss as long as a phenomenon known as handoff occurs. Accordingly, we devise data compensation models (DCM) to cope with data loss problem. In particular, the DCM neither aggravates any extra computing loads in federates nor exhausts memory storage in the period of mobile client’s short-term disconnection. As a consequence, the simulation results indicate that the proposed architecture of HLA federation supports the applicable mobility management, seamless data communication, and low system resource consumption for wireless and mobile distributed applications.

This paper proposes efficient channel assignment scheme for mobility prediction handover. In future mobile communication networks, the radius of the cell becomes smaller so as to utilize the limited channel efficiently. Because of the smaller radius of the cell, it is difficult to maintain Quality of Service (QoS) on account of occurring the call drop phenomenon and the insufficient channel during the terminal movement. In order to prevent these phenomena, the mobility prediction handover schemes are proposed. However, the problem is the bad effectiveness of the channel because existing channel assignment schemes ignore the mobility prediction handover. The proposed scheme maintains the dropping probability of handover calls, reduce the blocking probability of new calls, and increase utilization of channel.

SSL is one of the most popular protocols used on the Internet for secure communications. However SSL protocol has several problems. First, SSL protocol brings considerable burden to the CPU utilization so that performance and speed of the security service is lowered during encryption transaction. Second, SSL protocol can be vulnerable for cryptanalysis due to the fixed algorithm being used. Third, it causes a problem of mutual interaction with other protocols because of the encryption export restriction policy of the U.S. Fourth, it is difficult for developers to learn and use cryptography API for SSL. To solve these problems, in this paper, we propose an SSL component based on CBD. The execution of the SSL component is supported by Confidentiality and Integrity component. It can encrypt data selectively and use various mechanisms such as SEED and HAS-160. Also, it can complement the SSL protocol’s problems and, at the same time, take advantage of component. Finally, in the performance analysis, we present a better result than the SSL protocol as the data size is increased.

Semiconductor fabrication lines are organized using bays, equipment, and stockers. Most 300mm wafer lines use AMHS (Automated Material Handling System) for inter-bay and intra-bay lot transportation. In particular, the inter-bay AMHS moves lots between stockers, whereas intra-bay AMHS moves lots between stockers and tools, or between tools within the same bay. The key concern for manufacturer is how to raise productivity and to reduce turn-around time. This paper presents a simulation to reduce turn around time and raise productivity by reducing the delivery time (which affects AMHS).