• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.146-157
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• 2007

This paper discusses two algorithms for recommending notebook computer (NBC) and workstation adjustments so that the user can assume an ergonomic seated posture during NBC operation. Required input data are the user's anthropometric data and physical dimensions of the NBC and the workstation. The first algorithm is based on an assumption that there are no workstation constraints while the second algorithm considers the actual seat height and work surface height. The results from the algorithms include recommendations for adjusting the NBC (tilt angle of the NBC base unit, angle between the base and screen units, and base support height) and the workstation (heights of seat support and footrest, and distance between the body and the NBC).

• Journal of information and communication convergence engineering
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• v.10 no.2
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• pp.129-134
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• 2012

As application-specific requirements for wireless sensor networks emerge, both real-time and reliable communications become major research challenges in wireless sensor networks due to the many constraints on nodes and wireless links. To support these services, several protocols have been proposed. However, since most of them were designed as well as developed for general purpose applications, it is not recommended that they be directly adapted to applications with special requirements. In this paper, we propose a way to extend the current reliable transport protocol to cover a special real-time service, the (m,k)-firm deadline stream, in wireless sensor networks. While the proposed scheme is basically built on the PSFQ protocol for reliability, some features have been newly developed to support the (m,k)-firm stream efficiently. Finally, simulation results are given to demonstrate the feasibility of the proposed scheme in high traffic and with failed links.

• Korean Journal of Computational Design and Engineering
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• v.13 no.6
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• pp.412-420
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• 2008

In order to design the large complex structures like VLFS (Very Large Floating Structures), it is essential the cooperation between the experts in various fields; structural engineering expert, fluid mechanics expert, mooring system engineer, and so on. This paper describes the development of an integrated system to support the cooperative design between various experts and project manager. This integrated system is designed to be operated in Web environment and it contains the support of design DB and 3D graphical tool, negotiation tool for task allocation, and various engineering supporting tools for each design step. The user group of this system can be classified as Project Manager, Engineering Expert, DB Builder, and System Administrator. All of the engineering data is saved after and during the process of the design projects and all participants can be connected by Internet without the limit of time or space constraints.

• IE interfaces
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• v.11 no.1
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• pp.97-103
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• 1998

In these days many people have studied on the berthing problem. The operation rules differ from port so port and the problem is highly dependent on the environment of port. The purpose of this study is to develop a decision support system decision makers of the berthing problem for Inchon Port. The system is developed with graphic user interface(GUI) using user-interactive approach and some general and specific rules for Inchon Prot are considered. The system is composed of the following four parts ; the input/output part, the automatic berthing part by the system using rules, the manual berthing part by user, and the part for modifying results or handling exceptional events. The system is designed to assign ship to berths by matching the characteristics with environmental and operational constraints of Inchon Port. We expect that this system can provide decision makers with an efficient and fast way to berthing and can reduce wastes of time, space, and manpower in port operations.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.223-226
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• 2003

In this paper, we propose new agent discovery and route discovery schemes to support Mobile IP (MIP) in Ad Hoc networks with wireless backbone. The wireless backbone consisting of stationary wireless routers and Internet gateways (IGs) is a kind of wireless access network of IP-based core network. The proposed scheme utilizes favorable features of wireless backbone such as stable links and no energy constraints. In the agent discovery scheme, backbone-limited periodic Agent Advertisement (AA) and proxy-AA messages are used, which reduce network-wide broadcasting overhead caused by AA and Agent Solicitation messages and decentralize MIP processing overhead in IGs. In order to reduce delay time and control message overhead during route discovery far the destination outside Ad Hoc network, we propose a cache-based scheme which can be easily added to the conventional on-demand routing protocols. The proposed schemes can reduce control overhead during agent discovery and route discovery, and efficiently support MIP in Ad Hoc network with wireless backbone.

• IE interfaces
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• v.12 no.1
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• pp.56-67
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• 1999

This paper is about implementation issues for use of the Internet technology in education. An examination of the current status of virtual university provides guidance for subsequent prototype development. A virtual university is the Internet based process by which students increase their specific knowledge and skills via electronic interaction with content and people. Virtual university enables colleges and universities to provide students and faculty with network access to courseware and educational materials on multimedia servers free from time and geography constraints. In this paper, we present a prototype instruction support system (ISS). The ISS consists of the following components in architecture: Internet, software, hardware, database systems, users, and workflow. The ISS also assists several functions as follows: lecture notes, register processes, attendance checks, built-in boards, grading systems, questions and answers, electronic libraries, chats, and search engines. Our work will provide a guideline for the development of a virtual classroom for distance education and learning.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.653-656
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• 2000

We consider, in this paper, a UML-based design support system for real-time systems. However, the UML does not include any notion for verification of timing constraints. We presents transformation algorithms, as a function of the support system, of UML descriptions into Petri nets and Interval Temporal Logic models, which are very powerful for the verification. This paper shows also transformation example for simple elevator system.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.15-24
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• 2001

This study introduces an integrated decision support system (DSS) for the water supply system in Fukuoka City, Japan. The objective is to conceive a comprehensive tool that may aid decision-makers to derive the best water supply alternatives from a multi-reservoir system in order to minimize the long-term drought damages and threat of water shortage. The present DSS consists of graphical user interface (GUI), a database manager, and mathematical models for runoff analysis, water demand forecasting, and reservoir operation. The methodology applied explicitly integrates the drought risk assessment based on the concept of reliability, resiliency, and vulnerability, as constraints to derive the management operation. The application of the DSS to the existing water supply system in Fukuoka City was found to be an efficient tool to facilitate the examination of a sequence of water supply scenarios toward an improved performance of the actual water supply system during periods of drought.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.1
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• pp.31-43
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• 2021

In this study, approximate design optimization using various meta-models was performed for the structural design of active type deck support frame. The active type deck support frame was newly developed to facilitate both transportation and installation of 20,000 ton class offshore plant topside. Structural analysis was carried out using the finite element method to evaluate the strength performance of the active type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions that were regulated in ship classification organization. The approximate optimum design problem based on meta-model was formulated such that thickness sizing variables of main structure members were determined by achieving the minimum weight of the active type deck support frame subject to the strength performance constraints. The meta-models used in the approximate design optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. The results from approximate design optimization were compared to actual non-approximate design optimization. The Chebyshev orthogonal polynomials among the meta-models used in the approximate design optimization represented the most pertinent optimum design results for the structure design of the active type deck support frame.

• Journal of the Korea Computer Industry Society
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• v.2 no.3
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• pp.329-340
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• 2001

Video server which stores video streams should serve more users with the requested streams rapidly, satisfying their time constraints. For this objective, the storage system of the video server needs large disk bandwidth and buffer capacity. But, because given disk bandwidth and buffer capacity are limited, technologies that utilize effectively the given disk bandwidth and buffer capacity without waste might be needed. In this paper, we propose the policies that not only reduce the startup latency but also, support more users by utilizing the disk bandwidth and buffer efficiently, which also considering time constraint characteristics of video stream. In order to reduce the startup latency of the service requests, it inducts the effect of random access of disk head by moving asynchronously disk heads in multiple disk environments. Also, there are two technologies to support more users. First, the proposed policy reduces the seek latency by moving the disk head sequentially so that it saves the disk bandwidth. Second, it determines the segment size through considering both given buffer capacity and given disk bandwidth by heuristic approach in order to overcome the constraints of the number of streams supported due to limitation of buffer capacity. The segment size makes it utilize given buffer optimally with given disk bandwidth. The correctness of the proposed policies is not only analyzed theoretically but also evaluated through simulations.