• Journal of KIISE
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• v.44 no.2
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• pp.132-138
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• 2017

We design and implement a process-based fault recovery system to increase the reliability of new memory based computer systems. A rollback point is made at every context switch to which a process can rollback to upon a fault. In this study, a clone process of the original process, which we refer to as a P-process (Persistent-process), is created as a rollback point. Such a design minimizes losses when a fault does occur. Specifically, first, execution loss can be minimized as rollback points are created only at context switches, which bounds the lost execution. Second, as we make use of the COW (Copy-On-Write）mechanism, only those parts of the process memory state that are modified (in page units) are copied decreasing the overhead for creating the P-process. Our experimental results show that the overhead is approximately 5% in 8 out of 11 PARSEC benchmark workloads when P-process is created at every context switch time. Even for workloads that result in considerable overhead, we show that this overhead can be reduced by increasing the P-process generation interval.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.477-479
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• 2017

With the recent advances in medical technology and health care, the prevention and treatment of diseases has developed. Accordingly aging has rapidly progressed. In this life span and aging society, demand for diagnostic centered medical care is increasing rapidly. In this paper, we propose a wearable patient check system based on FPGA that can be controlled by sensors. In the existing hospital, a doctor or nurse visited the patient every hour to check the condition. However, in this paper, patients, doctors and nurses can check the patient's condition at the desired time using patient check system. In addition, the tilt sensor is used for the patient who is uncomfortable to easily control. The proposed FPGA-based hardware architecture consists of an algorithm for enlarged image processing, a TFT-LCD Controller, a CIS Controller, and a Memory Controller to output the patient's status image. Implemented and validated using the DE2-115 test board with Cyclone IV EP4CE115F29C7 FPGA device and its operating frequency is 50MHz.

• Journal of Korea Spatial Information System Society
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• v.8 no.3
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• pp.1-14
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• 2006

Recently, to efficiently support the real-time requirements of LBS and Telematics services, interest in the spatial main memory DBMS is rising. In the spatial main memory DBMS, because all spatial data can be lost when the system failure happens, the recovery system is very important for the stability of the database. Especially, disk I/O in executing the log and the checkpoint becomes the bottleneck of letting down the total system performance. Therefore, it is urgently necessary to research about the recovery system to reduce disk I/O in the spatial main memory DBMS. In this paper, we study an efficient recovery system for the spatial main memory DBMS. First, the pre-commit log method is used for the decrement of disk I/O and the improvement of transaction concurrency. In addition, we propose the fuzzy-shadow checkpoint method for the recovery system of the spatial main memory DBMS. This method can solve the problem of duplicated disk I/O on the same page of the existing fuzzy-pingpong checkpoint method for the improvement of the whole system performance. Finally, we also report the experimental results confirming the benefit of the proposed recovery system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.53-54
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• 2017

비콘 서비스란 가까운 범위 안에 있는 사용자 위치를 찾아 메시지 전송, 모바일 결제 등을 가능하게 하는 스마트폰 근거리통신 서비스로, O2O 실현에 핵심적인 역할을 담당한다. 비콘을 활용하면 사물과 상황인식, 콘텐츠 푸시, 실내위치 측위, 자동체크인, 지오펜스 등 다양한 서비스 제공이 가능하다. 본 연구에서는 비콘을 활용하여 출석을 체크하는 자동 출석 시스템을 구현하였다. 자동 출석 시스템에서는 사용자가 강의실에 들어오는 것을 인식하여 출석 검사를 하며, 이 자료를 인터넷을 통하여 데이터베이스에 저장한다. 다양한 강의를 구별할 수 있으며, 들어온 시간, 나간 시간 등의 검사가 가능하며, 이를 좀 더 보완한다면 상황인식 시스템으로써 다양한 서비스와 연계시킬 수 있다.

• The Korean Journal of Archival Studies
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• no.37
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• pp.273-305
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• 2013

In order to actively use of records and information in current digital record management systems, we have to check whether a system is designed to fully support the user of records and whether the good use of the system is being. This study analyzed the status of the use of the search function of Records Management System(RMS) for public agencies, and evaluated them. In order to investigate the status of the use of the search function, it surveyed records managers of public agencies using the RMS. The result showed that records managers unsatisfied with the usability and the search performance of the RMS. To evaluate the search function, it identified the functional requirement of the system and develops a checklist that can be used for evaluation. Two assessments were conducted. Firstly, as pre-evaluation, it assessed the degree of implementation of the current RMS according to the checklist as an inspection chart using document examination method. Secondly, it assessed the degree of implementation using a survey of records managers of public agencies that use the RMS. Assessment results show the improvement of the basic features that are essential to the system is required. In particular, the search function is required to improve user-friendliness for the user. For the advance of RMS, this study discusses the necessity for improvement of the search functions, the build of continuous maintenance and management system, and the user education.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.179-180
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• 2015

국제해사기구에서는 사용자 중심의 운항환경 구축을 위해 SQA & HCD 가이드라인을 제안하였으나 이는 인간중심설계(Human Centred Design)를 위한 일반적이고 개념적인 접근방법이다. 본 연구에서는 선교의 다양한 항해장비들 중 ECDIS를 대상으로 실무에서 활용 가능한 사용성 평가항목 및 체크리스트를 개발하여 제안하고자 한다.

• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.158-164
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• 2011

Check valves developed for aerospace applications and commercially available for the applications are investigated. The examples include the ones for launch vehicles, SSME (Space Shuttle Main Engine) and GSE (Ground Support Equipment) purges developed by NASA, requiring high reliability, and the ones by KARI. Also the commercial ones for room and cryogenic temperatures by major valve US companies. Relations of design factors such as seal materials and spring rate to principal performances like operating temperature/pressure and cracking pressure are explained. Then potential operational problems such as chatter and contaminations are explained. Also, filters, fittings for end connections and cleanliness requirements for the applications are considered.

• Journal of IKEEE
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• v.23 no.1
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• pp.22-28
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• 2019

This paper presents the monitoring method of machining error and quality check to improve the productivity of boring manufacturing process. Machining error usually appears as the offset of spatial location of actual cutting path compared to ideal cutting path. In order to monitor an error of workpiece, multiple factors affecting quality of boring, such as distortion of workpiece, clamping error, radial rotation error of the spindle and motion error of machine tools, were took into account. To verify the productive quality, we propose the quality check system. The system based on IT convergence analyzes the process error rate and saves the analyzed data in memory. Also, these play important roles in detecting an inferior production goods and can decrease the production cost and loss of bearing.

• Proceedings of the Korean Society for Information Management Conference
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• 2011.08a
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• pp.53-58
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• 2011

빠르게 진화하는 상용 웹 사이트들의 검색 및 인터페이스 기술과 달리 도서관의 OPAC 시스템은 그 변화를 빨리 수용하지 못해 그 결과로 OPAC 사용에 있어 이용자들은 불편을 느끼고 있다. 이처럼 도서관 OPAC의 진보적인 개발이 시급한 실정에서 등장한 개념이 '차세대 OPAC'이다. 본 연구는 차세대 OPAC의 특성을 열거하여 핵심 항목으로 구성 된 체크리스트를 개발하고 향후 이를 이용하여 대학도서관에서의 차세대 OPAC 적용 현황을 평가 분석하는 도구로 사용하고자 하였다. 본 논문에서는 최종적인 연구의 초기단계로 차세대 OPAC에 관한 선행연구 분석을 통해 체크리스트 예비 항목을 작성하는 것으로 제한한다.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.47-53
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• 2003

차세대 웹 문서의 새로운 표준으로 자리 잡아 가고 있는 XML은 전자 상거래나 병원 관리 등과 같이 다양한 응용 분야에 적용되고 있다. 이러한 응용 분야는 XML 문서의 각 구성 요소 수준의 세밀한 액세스 제어를 요구한다. 따라서, 현재 XML 문서의 미세 접근 제어 기법에 대한 연구가 활발히 이루어지고 있다. 현재 제안된 XML 문서를 위한 미세 접근 제어 기법은 대부분 묵시적 권한 기법을 사용하여 상위 구성요소에 한번의 권한 부여로 하위노드에 권한을 부여하는 효과를 가지는 장점을 가지나, 각 구성 요소간의 권한을 체크하는 시간 오버헤드를 가지는 단점이 있다. 본 논문에서는 권한을 체크하는 시간을 감소시키기 위하여 XML 문서의 미세 접근 제어를 위한 명시적 권한 기법을 제안하고, 이를 이용하여 노드의 권한에 대한 모든 정보를 저장하고 있는 접근 권한 트리 모델을 제시하였다. 본 논문에서 제안한 접근 권한 트리 모델을 사용하면, 권한 정보를 저장하는 공간 오버헤드가 있지만, 권한 체크 시간을 감소시켜 사용자에게 보다 빠른 뷰를 제공할 수 있다.