• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.29-40
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• 1999

The distribution center location and routing problem involves interdependent decisions among facility, transportation, and inventory decisions. The design of distribution system affects the customers' purchase decision by sets the level of customer service to be offered. Thus the lower product availability may cause a loss of demand as falls off the customers' purchase intention, and this is related to the firm's profit reduction. This study considers the product availability of the distribution centers as the measure of the demand level change of the demand points, and represents relation between customer service and demand level with linear demand function. And this study represents the distribution center location and routing to demand point in order to maximize the total profit that considers the products' sales revenue by customer service, the production cost and the distribution system related costs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6A
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• pp.397-404
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• 2003

In this paper, we have analyzed the level of cross-modulation noise required for CDMA mobile station and proposed a guideline for optimum design. From the analysis, the level of cross-modulation noise is determined by the system's noise figure(NF) and VCO's phase noise and there is a trade-off relationships between them. In addition, we have determined the value of LNA's IIP3 and duplexer's isolation to satisfy the above level in designing the system. Therefore, this paper will give a guideline for a selection of components in designing cdma2000 mobile station.

• Journal of the military operations research society of Korea
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• v.28 no.2
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• pp.1-19
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• 2002

This study shows the effect of inventory policy change from supplier-based to customer-based. We focus on the service level, cost, and information distortion of the Military Supply Chain(MSC) with System Dynamics. We design MSC model according to field practician interviews by using Vensim. The simulation makes a comparison between supply-based inventory policy performances and order-based inventory policy performances. In order to evaluate the MSC performances, we measure the accumulation of backlog(service level), supply chain cost, and order percentage overshoot(information distortion). The results show that 1) changing inventory policy from supplier-based to end customer order-based gets a good customer service, reduces MSC cost, and prevents information distortion, 2) changing inventory policy from supplier-based to immediate customer order-based reduces a small amount of MSC cost and deteriorates customer service, and 3) supply level is main factor for MSC performances improvement. This study implicates the policy change makes a improvement of MSC performance without introducing information system.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.4
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• pp.269-278
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• 2020

In this paper, two types of DC/DC converters in a hydrogen fuel cell hybrid railway vehicle system, which serve to charge high-voltage battery and supply power to an inverter for driving a driving motor, were compared and analyzed. A two-level interleaving boost converter and a three-level boost converter were compared and analyzed, and a theoretical design method was proposed to have an efficiency characteristic of over 95%. In addition, a digital controller design method considering the digital phase delay component of DSP (TMS320F28335) is presented. Finally, the validity of the theoretical design of the converter with 20kW power was verified through static and dynamic experiments respectively.

• The KIPS Transactions:PartA
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• v.9A no.4
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• pp.459-466
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• 2002

Modern embedded system employs a hybrid architecture which contains a general micro processor and reconfigurable devices such as FPGAS to retain flexibility and to meet timing constraints. It is a hard and important problem for embedded system designers to explore and find a right system configuration, which is known as design space exploration (DSE). With DES, it is possible to predict a final system configuration during the design phase before physical implementation. In this paper, we implement a timing analysis simulator for a DSE on a hybrid embedded system. The simulator, integrating exiting timing analysis tools for hardware and software, is designed by extending Y-chart approach, which allows quantitative performance analysis by varying design parameters. This timing analysis simulator is expected to reduce design time and costs and be used as a core module of a DSE for a hybrid embedded system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.952-960
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• 2007

Most Websites perform login process for authentication. But simple features like ID and Password have no trust because most people worry about appropriation. So the youth can easily access illegal media sites using other's ID and Password. Therefore this paper examine features be adaptable to authentication system, and propose a design of authentication system using multiple features. A proposed authentication system has two categories, such as low-level and high-level method. Low-level method consists of grant of authentication number through mobile phone from server and certificate from authority. High-level method combines ID/Password and features of fingerprint, character, voice, face recognition systems. For this, this paper surveys six recognition systems such as fingerprint, face, iris, character, vein, voice recognition system. Among these, fingerprint, character, voice, face recognition systems can be easily implemented in personal computer with low cost accessories. Usage of multiple features can improve reliability of authentication.

• Korean Journal of Geomatics
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• v.1 no.1
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• pp.61-67
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• 2001

This study aims to develop the Extended Urban Land Information System (EULIS) which can support the sustainable urban management. Although the existing Urban Land Use Information system (ULUIS) that aids the micro-level land use information is a good means for the understanding of urban spatial structure and district-level planning and management (such as urban design, redevelopment planning and district-level transportation planning, etc.), it has some limitations in supplying the information for sustainable urban management, such as environmental and traffic analysis, urban infrastructure's carrying capacity analysis, etc. The EULIS is designed to efficiently supply the information for sustainable urban management. For the successful construction of EULIS, the followings have to be considered. 1) the integration of topographic maps which contain the building's footprints and cadastral maps which contain the parcel's boundary, 2) the integration of EULIS and FM (Facility Management) system for the full utilization of information about capacity analysis of infrastructure, 3) the construction of standardized georeferencing system and spatial unit for the combined use of environment and traffic census data. This study shows 1) why EULIS is needed for the sustainable urban management and which elements are needed for the system,2) the E-R data model for the EULIS, 3) the strategies for the construction of EULIS and 4) the conclusion.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.86-92
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• 2014

This paper provides an integrated view on human and system interaction in advanced and automated systems, which adopting computerized multi-functional artifacts and complicated organizations, such as nuclear power plants, chemical plants, steel and semi-conduct manufacturing system. As current systems have advanced with various automated equipments but human operators from various organizations are involved in the systems, system safety still remains uncertain. Especially, a human operator plays an important role at the time of critical conditions that can lead to catastrophic accidents. The knowledge on human error helps a risk manager as well as a designer to create and control a more credible system. Several human error theories were reviewed and adopted for forming the integrated perspective: gulf of execution and evaluation; risk homeostasis; the ironies of automation; trust in automation; design affordance; distributed cognition; situation awareness; and plan delegation theory. The integrated perspective embraces human error theories within three levels of human-system interactions such as affordance level, psychological logic level and trust level. This paper argued that risk management process should dealt with human errors by providing (1) reasoning improvement; (2) support to situation awareness of operators; and (3) continuous monitoring on harmonization of human system interaction. This approach may help people to understand risk of human-system interaction failure characteristics and their countermeasures.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.3
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• pp.339-347
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• 2021

Recently, the incidence of lightning in Korea has been increasing more and more. The damage caused by lightning is also getting worse. Lightning protection system is a prerequisite, not a sufficient condition. Considering the characteristics of lightning, there is a high frequency of lightning strikes in highlands. So, high grades of LPS should be applied to ground facilities of anti-aircraft weapons systems. 4-Level LPS was applied on groung facilities of anti-aircraft weapons system based on lightning incidence rate in past. There are some possibilities of damage from lightning in anti-aircraft weapons system. So, we have to readjust the LPS level with grounding, lightning rods and surge protect device based on lightning incidence rate in now days. Propose 2-level LPS and design with lightning rods, surge protector, separated grounding in this paper.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1138-1146
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• 1990

A knowledge-based expert system has been developed implementing the ambiguous process of conceptual design of flywheels in earlier design stage to assist the selection of proper flywheel types and dimensions. Knowledge for the flywheel design consists of the rules for conventional as well as super flywheels and other informations required for the design process. Those knowledges were extracted from literatures and some experts in the field. With these knowledges, an integrated knowledge based expert system was developed to help users with informations and facilities to design flywheels interactively using a commercial package of knowledge-based system called INSIGHT2 of backward chaining and proprietary package of forward chaining written in LISP language. The developed system consists of the knowledge base part and calculation park : the first one consists of main module and user level modules and the other one is to assist in analyzing the stress distribution in the flywheels and deciding the flywheel dimensions and specifications for various types of flywheels using proper data bases and graphic facilities. With this flywheel design software, several examples were tried generating acceptable design results.