In distributed replicating server model, providing replicated services is able to improve the performance of providing a service and efficiency for several clients. And, the composition of the server selection algorithm is efficiently able to decrease the retrieval time for replicated data. In this paper, we define the system model that selects and connects the replicated server that provides optimal service using server-side downstream measurement and proposes an applicable algorithm.

The goal of a distributed simulation such as battle field simulation is to combine all kinds of simulations in the same synthetic environment and to make people interact at the same time. It is a key issue to share the same synthetic environment among simulations. To support reusability and affordability in the modeling and simulation area, DMSO(Defense Modeling and Simulation Office) of USA developed concepts such as HLA(High Level Architecture) and SEDRIS (Synthetic Environmental Data Representation and Interchange Specification). In the industrial simulation area, the digital manufacturing is the main stream. To reduce cost and to reuse simulation environment, the standardization becomes the focus of digital manufacturing. This study proposes to use SEDRIS to improve interoperability of manufacturing data. The simulation data of DELMIA, which is a leading commercial digital manufacturing solution, is mapped and translated into the SEDRIS transmittal format. Mapping of the manufacturing simulation data and the synthetic environment are implemented and verified through experiments.

Determination of component mounting sequence on printed circuit board assembly process is a typical NP-hard problem. It is a kind of traveling salesman problems, but it has one more hard to meet constraint of matching component type per mounting position as well as searching the shortest path. An efficient method is developed by separation of crowed area and allowing up to two slots per component type. A simulation model is constructed using Visual C++ for evaluation of the suggested heuristic.

Feedwater heaters of many nuclear power plants have recently experienced wall thinning damage, which will increase as operating time progresses. As it is judged that the wall thinning damages have generated due to local fluid behavior around the impingement baffle installed in downstream of the high pressure turbine extraction steam line to avoid colliding directly with the tubes, numerical analyses using PHOENICS code were performed for two models with original clogged impingement baffle and modified multi-hole impingement baffle. To identify the relation between wall thinning and fluid behavior, the local velocity components in x-, y-, and z-directions based on the numerical analysis for the model with the clogged impingement baffle were compared with the wall thickness data by ultrasonic test. From the comparison of the numerical analysis results and the wall thickness data, the local velocity component only in the y-direction, and not in the x- and z-direction, was analogous to the wall thinning configuration. From the result of the numerical analysis for the modified impingement baffle to mitigate the shell wall thinning, it was identified that the shell wall thinning may be controlled by the reduction of the local velocity in the y-direction.

There are electric double layer capacitance, polarization resistance and solution resistance in the interface between electrode and solution. Electrode process could be evaluated by the electrical impedance analysis. The necessities of the electrochemical cell analysis with high speed impedance analyzer are followings: minimization of the effects of electric stimulation on electrochemical cell and the concentration of reactive materials, and optimization of impedance signal resolution. This paper represents the design criteria for the selection and stimulation to develop fast impedance analyzer prototype for a electrochemical cell. It was suggested that the design of 470k sample/s sampling rate, 13 bit ABC resolution, and 140ms recording time is required for high speed impedance analysis system in frequency range between dc and 10kHz.

A simulation for the analysis of the evasive capability of a conventional costal submarine against a light Anti-Submarine Warfare (ASW) torpedo has been studied. The Torpedo, Submarine Controller, Devoy, and Jammer models of this simulation are analysised and designed using Unified Modeling Language (UML) and in addition they are modeled Discrete Event System Specification (DEVS). We examine maximum speed, acceleration, countermeasure systems capabilities of a submarine, and sonar range of a torpedo as the factors which affect the evasive capability of the submarine. This paper shows the relationships between those various factors and the submarine's evasive capability as the outcome of the simulation. The simulation models can be applied for simulation based acquisition (SBA) of a submarine system.

이 논문에서는 메타데이터 레지스트리간의 메타데이터 교환을 위해 제안된 교환 프로토콜의 장점을 명시적으로 보이기 위한 시뮬레이션 결과에 대하여 기술한다. 기존 접근 방법들은 교환 메커니즘의 높은 복잡도, 지역 메타데이터 관리 시스템으로의 종속성, 새로운 메타데이터 관리 시스템의 추가를 위한 높은 비용 등의 문제점을 지닌다. 이를 해결하기 메타데이터 교환 프로토콜이 제안되었다. 그러나 지금까지의 연구에서는 정성적으로만 그 장점을 보였다. 이 논문의 목적은 정략적 관점에서 제안된 프로토콜의 장점을 기술하고자 함에 있다. 특히 이 논문에서는 질의 효율이 가장 중요한 문제로서 다른 요인에 의한 결과에도 영향을 주기 때문에 질의 효율성 문제에 초점을 둔다. 이를 위해 평가 항목과 평가 모델에 대해 정의한다. 질의 효율성 평가를 위한 요인 중에서 대상 메타데이터의 개수, 각 메타데이터를 구성하는 컴포넌트의 개수 및 각 컴포넌트들을 구성하는 속성들의 개수를 주 파라미터로 이용하였다. 이에 따라 시뮬레이션은 크게 세 가지 유형을 지니게 된다 정량적 평가를 통해 교환 프로토콜이 요구되는 이유와 그 정당성을 명시적으로 보인다.

Access networks connected in B3G networks provide its property network service. Hence, though mobile users may utilize only a network service from an access network, they can also use variety of network services from several access networks for their service satisfaction. To support heterogeneous changeable network service in access networks, the mobile terminal must implement heterogeneous system techniques so that it is able to change the network service by ISHO (Inter-System Handover) In this paper, we present the ISHO condition by the policy-based framework in B3G networks. Also, we propose an ISHO scheme to control network resources for the QoS management of a mobile session between UMTS and WLAN access networks. To support the QoS management, the proposed scheme is that it will be implemented before the resource exhaustion occurs to effect network performances.

This paper presents characteristics of a virtual human's navigation using a limited perception-based mapping. Previous approaches to virtual human navigation have used an omniscient perception requiring full layout of a virtual environment in advance. However, these approaches have a limitation on being a fundamental solution for a human-likeness of a virtual human, because behaviors of humans are basically based on their limited perception instead of omniscient perception. In this paper, we integrated Hill's mapping algorithm with a virtual human to experiment virtual human's navigation with the limited perception. This approach does not require full layout of the virtual environment, 360-degree's field of view, and vision through walls. In addition to static objects such as buildings, we consider enemy emergence that can affect an virtual human's navigation. The enemy emergence is used as the variable on the experiment of this present research. As the number of enemies varies, the changes in arrival rate and time taken to reach the goal position were observed. The virtual human navigates by two conditions. One is to take the shortest path to the goal position, and the other is to avoid enemies when the virtual human encounters them. The acquired result indicates that the virtual human's navigation corresponds to a human cognitive process, and thus this research can be a framework for human-likeness of virtual humans.