• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.599-604
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• 2018

For missile systems, sustaining high reliability and ensuring economical maintenance are very important. In the Republic of Korea, for most missiles, periodic inspection is mandatory for missiles in the field. Every fixed number of years, they are returned to the ordnance depot to be tested and repaired if faults are found. Almost all missiles have a built-in test (BIT) capability. With the BIT, faulty missiles can be isolated anytime during operations or storage in the launchers. So the reliability and the maintenance costs of the missiles greatly depend on the length of the inspection cycle and the BIT/inspection quality. In this paper, we suggest a model for predicting the storage reliability of missiles subjected to non-periodic tests and periodic inspections, excluding overlapping failures. Some numerical examples are given. This model will be useful for determining the length of the periodic inspection cycle.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1130-1141
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• 2015

Conventionally, a pulse radar is used for middle-sized or large-sized ships to detect other ships or obstacles located at a long distance. However, it is hardly equipped for most of the small-sized ships due to mounting and maintenance costs. Therefore, FMCW(frequency modulated continuous wave) radar is suggested as an alternative for the small-sized ships. Since it operates with low power and has good range resolution for relatively close objects, it is eligible for the small-sized ships. In previously proposed FMCW radar system, it only estimates distance and velocity of a target ship placed in the direction of main beam and is hard to detect several ships simultaneously. Thus, we suggest the method for detecting several ships at the same time by applying MUSIC(multiple signal classification) algorithm to FMCW radar signal received by a phased array antenna. In addition, by combining digital beam forming with the MUSIC algorithm, better angle resolution is achievable.

• 대한공업교육학회지
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• v.33 no.2
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• pp.325-339
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• 2008

In this paper, we developed a module that can execute the data acquisition of the real-time measured radiant rays in the specific part of the nuclear power station. This module that includes the RF communication function, paces around the power station, being loaded on robot and can obtain the generated radiant rays in the various places through the detecting devices. It is considered that this new developed radiant rays acquisition method will have the higher degree of efficiency as compared with the existing method and reduce the expenses of the maintenance and repair work.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.821-829
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• 2020

Health management system of airborne software repairs runtime errors to provide safety and to reduce cost of maintenance. It is critical to on-the-fly repair order violation errors, because it is difficult to identify them at the development phase. Previous work, called Repairing Atomicity Violations (Repairing-AV) diagnoses order violations for each access event by comparing execution order of accesses. As a result, Repairing-AV has time overhead that is proportional to the number of access events to shared variable. This paper presents a tool called On-the-fly Repairing System (ORS) that can repair order violations of object methods containing access events. The ORS diagnoses order violations by using correct order of object methods, and treats them by stalling its thread where the error is about to occur. Experimentation with five synthetic programs shows that ORS is more efficient than Repairing-AV when the number of access events is greater than sixty.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.4
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• pp.45-51
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• 2009

Different countries around the world, using their traditional culture as a background, are promoting new changes and reformation in development and publicity method of cultural contents to promote national interests and to increase their competitiveness. Also, as the citizen's standard of living and quality of living goes up, various demands for the enjoyment of traditional culture goes up accordingly as well. As the cultural assets environment become more complicated and diverse, there is a need for systematic management and preservation plan. Keeping these viewpoints in mind, the geo-spatial information provision service using the web provides various forms of services such as satellite imagery, terrain, and 3D viewing, enabling the user to gain concrete spatial information on specific areas. The geo-spatial information using 3D modeling is done only in limited spaces because of construction expenses or difficulties in management and maintenance. In this thesis, I would like to propose Effective method for the GoogleEarth Uploading through simplification of 3D object for the publicity of traditional buildings and Cultural Resources and Tourist Attractions.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.103-105
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• 2006

최근 기업들은 분산된 조직과 각 조직의 목적에 따라 데이터베이스도 분산되어 있기 때문에 이들 간의 공유 및 협업을 통한 상호 운용성을 지원하기 어려우므로 일관적인 형태로 연동하기 위해서 메타데이터 수준의 표준이 필요하다. 또한 협업적인 거래환경에서의 EAI시스템은 다양한 정보 시스템에서 관리되는 지식들을 유기적으로 통합하고 공유함으로서 효율적인 검색 및 비용절감 등 많은 효과를 기대할 수 있다. 그러나 기존의 시스템은 특정 목적에 따라 관리되고 공유되므로 사실상 통합 외 공유에는 상당한 어려움이 있다. 따라서 본 논문에서 제시하는 XMDR은 온톨로지와 메타데이터 결합된 형태로 각종 표준들을 일관적인 형태로 온톨로지와 시소러스 개념을 도입함으로서 데이터수준의 정보를 통합 하기위한 메타데이터 공유 및 정보 시스템 통합의 일관성을 유지 할 수 있다. 본 논문에서 제시되는 브리지 XMDR 검색시스템은 원시데이터 계층, XMDR 계층. 브리지 XMDR 계층으로 3계층으로 구성된다. XMDR 계층은 분산된 데이터베이스의 속성표현의 표준과 관계성을 정의한 표준 온톨로지, 카테고리 분류 온틀로지, 사이트의 정보를 제공하는 로케이션 온톨로지로 구성되는 XMDR을 정의한다. 브리지 XMDR 계층은 XMDR간의 정보를 공유하기 위한 공유 도메인 속성을 추출한 하이브리드 통합방식으로 업무간의 의미적 통합이 가능하다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.143-148
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• 2001

Digital documentation is now becoming a must throughout a building process including design, construction, inspection, procurement and even facility management. The Internet is a backbone of such process, and web-based information exchange is the standard among other mainstream technologies. The current information management techniques, however, is heavily dependant on the server-side processing, which naturally results in the overload of the overall system. This paper proposes an XML-based approach in order to resolve such problems. A VE system was developed to demonstrate the efficiency of the XML solution, in term of efficient VE data management and fast decision making. also in this paper suggests 1) introduce XML based DBMS to improve data management efficiency and 2) introduce Mobile Computing to improve data accessibilities on sites.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.597-604
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• 2011

The various Smartphone platforms that are used currently make difficult to build efficient applications("apps") for Smartphone. Introduction of middleware in the Smartphone environment is being studied to solve this problem. By enhancing interoperability between server systems and Smartphone platforms as introducing this middleware supports efficiently for Smartphone apps to be developed and managed. Thus, the development of this middleware for Smartphone has become essential for the purpose of responding actively to the rapidly expanding Smartphone market. In this research, we designed and implemented Smartphone middleware which optimizes the cost and time for developing new application service and maintaining it. In order to test this implemented middleware's performance and its capabilities, we also developed university Smartphone apps and activated campus twitter.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.57-65
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• 2002

The Electrical Power System (EPS) shall supply required power to maintain spacecraft and payload during the mission. The EPS sizing are based on space environment, satellite mission and lifetime, and allocated budgets. The type of the primary and secondary power is determined according to satellite design-level and allocated subsystem budgets. The design of EPS has closely related to system and others' subsystems design. To supply the sufficient power to the satellite, the implementation of the larger power source and energy storage is impossible actually. And there will be some problems of the attitude control of the satellite, the handling power capability of the electronic boxes, and launch vehicle selection caused by EPS oversizing. Also, the thermal control is not easy in the space by extra power. And the maintenance of the satellite within the specific orbit from orbit-drag is a big design burden of the thruster. So the various technologies have been developed to optimize the EPS sizing and to operate the power system efficiently.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.103-109
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• 2016

In order to get the maintenance work for the normal operation of rail vehicles made safe maintenance training, which looked suffered direct physical train maintenance environment, gain experience to get out foster the practical skills, but experience the real maintenance in operational problems the maintenance procedures followed are difficult to be. So it can gain experience and knowledge of the actual maintenance work in safe conditions if you apply a simulation experience in a similar environment as possible to the actual train maintenance training can also reduce operational training costs. For a description of the current domestic and simulation programs of the railway sector it has been operating in overseas and is designed to train intensive training, maintenance and maintenance-related information is scarce situation. In this study, the contents of the theory of educational technology for effective training of train maintenance elements exhibit theory, theory of learning situations, designed to train maintenance training simulation through a previous study that investigated the problem-based learning theory.