• Title/Summary/Keyword: Service Failure

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An Efficient Recovery System for Spatial Main Memory DBMS (공간 메인 메모리 DBMS를 위한 효율적인 회복 시스템)

  • Kim, Joung-Joon;Ju, Sung-Wan;Kang, Hong-Koo;Hong, Dong-Sook;Han, Ki-Joon
    • 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.

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Development of the Phased Array Ultrasonic Testing Technique for Nuclear Power Plant's Small Bore Piping Socket Weld (원전 소구경 배관 소켓용접부 위상배열 초음파검사 기술 개발)

  • Yoon, Byung-Sik;Kim, Yong-Sik;Lee, Jeong-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.4
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    • pp.368-375
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    • 2013
  • Failure of small bore piping welds is a recurring problem at nuclear power plants. And the socket weld cracking in small bore piping has caused unplanned plant shutdowns for repair and high economic impact on the plants. Consequently, early crack detection, including the detection of manufacturing defects, is of the utmost importance. Until now, the surface inspection methods has been applied according to ASME Section XI requirements. But the ultrasonic inspection as a volumetric method is also applying to enforce the inspection requirement. However, the conventional manual ultrasonic inspection techniques are used to detect service induced fatigue cracks. And there was uncertainty on manual ultrasonic inspection because of limited access to the welds and difficulties with contact between the ultrasonic probe and the OD(outer diameter) surface of small bore piping. In this study, phased array ultrasonic inspection technique is applied to increase inspection speed and reliability. To achieve this object, the 3.5 MHz phased array ultrasonic transducer are designed and fabricated. The manually encoded scanner was also developed to enhance contact conditions and maintain constant signal quality. Additionally inspection system is configured and inspection procedure is developed.

Policy Measures for Improving Health Care Services in Rural Areas (농촌보건의료서비스 향상을 위한 제도 개선방안)

  • Moon, O.R.;Lee, L.S.;Park, J.Y.;Ko, D.H.;Lee, K.H.
    • Journal of agricultural medicine and community health
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    • v.16 no.2
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    • pp.97-119
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    • 1991
  • Korea has made a rapid economic development since the last three decades. This has helped Korea narrow the gap in health service differences in resource availability and in quality of care. However urban and rural differentials are still remarkable. This study has maintained that health status of rural residents is inferior to that of urban dwellers. Therefore, this study was carried out to develop policy measures for improving health services in rural areas. In order to achieve the objective of this study the authors collaborated closely and made field visits, interviews and conducted an extensive literature review regarding rural health services. The following policy options are recommended as a summary ; First, the quality of rural health personnel is a single most important factor influencing the level of rural health services. An innovative program for public health doctors to the internship and/or residency training program such as specialty board program of family medicine. Second, dissatisfaction regarding employment of public health doctors is problematic. More rational employment and deployment programs are needed to meet their personal desire. One way to do this is to make it wide open and competitive. Third this study shows how to increase physician productivity in the rural public health sector. Incentive system needs to be elaborated for the career development of rural health workers. University linked job opportunity as clinical professor is an example. Fourth, without straightening the function of health centers and subcenters, the future of rural health services is doomed to failure. Straightening primary health care is one way to enrich the program of public health facilities and reactivating the operation of health center/hospital is another. A close linkage of public facilities with private hospitals is a minimum requirement for the operation of health delivery system within a health district. Fifth, some measures are urgently required to enhance hospital services in medically underserved areas. Financial subsidy, tax exemption, long-term public loans and higher priority of health manpower deployment are some of them. Sixth, new health programs should be in tiated to meet changing needs of peoples in rural areas. Home health care program, hospice program, nursing home, residential program for the elderly are recommended.

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Suggestion, Design, and Evaluation of a New Modified Double Tee Slabs (새로운 개량 더블티 슬래브의 제안, 설계 및 평가)

  • Yu, Sung-Yong
    • Journal of the Korea Concrete Institute
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    • v.20 no.6
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    • pp.809-820
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    • 2008
  • A new modified full scale double tee slabs with the length of nib plate - 1,500 mm were suggested, designed, and experimentally evaluated up to the loading of flexural failure. This slabs were composed of the tee section which was same to original PCI double tee and the plate section which was modified in a new shape, and the prestressing force was applied at the bottom of tee section only. This specimens were made from the domestic precast factory. The safety and serviceability of the modified nib plate with the dapped ends were evaluated up to the ultimate flexural strength of tee section. As the experimental loading increased, the flexural crackings developed first in the bottom of the slab and they changed to the increased flexural shear and inclined shear crackings in the nib and dapped portion of the double tees. The suggested modified double tee slabs failed in ductile above the design loading with many evenly distributed flexural crackings. The thickness of nib plate - 250 mm does not show any cracking under the service loading and show several minor flexural cracking up to the ultimate state of tee portion. The proposed specimens were satisfied with the strength and ductility requirements in the design code provisions in the tests. Additional experimental tests are required to reduce the depth and tensile reinforcement of nib plate concrete for the practical use of this system effectively.

Experimental Verification of Flexural Response for Strengthened R/C Beams by Stirrup Partial-Cutting Near Surface Mounted Using CFRP Plate (CFRP 플레이트 적용 스터럽 부분절단형 표면매립공법으로 보강된 철근콘크리트 보의 휨 거동에 대한 실험적 평가)

  • Oh, Hong-Seob;Sim, Jong-Sung;Ju, Min-Kwan;Lee, Gi-Hong
    • Journal of the Korea Concrete Institute
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    • v.20 no.6
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    • pp.671-679
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    • 2008
  • The near surface mounted (NSM) FRP strengthening method has been conventionally applied for strengthening the deteriorated concrete structures. The NSM strengthening method, however, has been issued with the problem of limitation of the cutting depth which is usually considered as concrete cover depth. This may be related with degradation of bonding performance in long-term service state. To improve the debonding problem, in this study, the Stirrup partial-cutting NSM (SCNSM) strengthening method using CFRP plate was newly developed. SCNSM strengthening method can be effectively applied to the deteriorated concrete structure without any troubles of insufficient cutting depth. To experimentally verify the structural behavior, the flexural test of the concrete beam by using the SCNSM strengthening method was conducted with the test variable as the strengthening length (32%, 48%, 70%, 80%, 96% of span length). In the result of the test, the NSM and SCNSM strengthened specimen showed similar structural behavior with load-deflection, mode of failure. Additionally, there was no apparent structural degradation by the stirrup partial-cutting. Consequently, it was evaluated that the SCNSM strengthening method can be useful for seriously damaged concrete structures that is hard to apply the conventional NSM strengthening method for increasing the structural capacity.

A Model Curriculum Development for Clinical Nurse Specialist Training Program in Organ Transplant (장기이식 전문간호사를 위한 교육과정 연구)

  • Kim, Jung-Soon
    • The Journal of Korean Academic Society of Nursing Education
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    • v.6 no.2
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    • pp.171-185
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    • 2000
  • The twenty-first century may be said to be entering into a specialized qualification age to meet the needs of new technical innovations such as environmental changes, demographical changes, changes in the constitution of diseases, changes in the needs of the national health, reforms of information and knowledge, etc., which requires the provision of competitive services that can fulfill the high level needs of consumers. In consequence, it is needed to apply a practical nursing model that can serve as a guide for healthy society and to secure the sphere that can affect nursing policy-making by keeping pace with the changing environment. Furthermore, it is also urgent to expand more the activity sphere of nurse specialists with authority and autonomy, establish their legal foundation, establish a qualification accreditation system for nurse specialists, and develop educational programs. In Korea, the law relative to organ transplant past the national assembly on February 9, 2000, legally acknowledged brain death, which indicated to us the emergence of an age of organ transplant. Therefore, it necessitates to find out those of brain death from whom organ transplant is feasible in clinical practices, with their families' consent link to those terminal organ failure patients who are in need of an organ, and mediate both parties so that smooth transplant can be accomplished. A series of these complicated procedures require systematically trained specialists with high level techniques of organic management. With this in mind, this study was conducted on 69 clinical nurse specialists for organ transplant, accredited by the hospital, who are in active service in clinical practices. The resultant findings were revealed, as follows: 1. The qualifications of clinical nurse specialists for organ transplant should be accredited by Ministry of Health and Welfare or Korea Nurses Association. 2. The validity of qualifications should be for three years, and their renewal should be based on marks of a supplemental training or an education course for more than 12 hours a year. 3. The qualification of the clinical nurse specialist necessitates theoretical lectures and practices on those nurses who have had clinical experience in the pertinent field. 4. The course of training is required to be one year in the length of training and take more than 20 credits (320 hours) and 5 credits (240 hours).

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Fast Selection of Composite Web Services Based on Workflow Partition (워크플로우 분할에 기반한 복합 웹 서비스의 빠른 선택)

  • Jang, Jae-Ho;Shin, Dong-Hoon;Lee, Kyong-Ho
    • Journal of KIISE:Software and Applications
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    • v.34 no.5
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    • pp.431-446
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    • 2007
  • Executable composite Web services are selected by binding a given abstract workflow with the specific Web services that satisfy given QoS requirements. Considering the rapidly increasing number of Web services and their highly dynamic QoS environment, the fast selection of composite services is important. This paper presents a method for quality driven comosite Web services selection based on a workflow partition strategy. The proposed method partitions an abstract workflow into two sub-workflows to decrease the number of candidate services that should be considered. The QoS requirement is also decomposed for each partitioned workflow. Since the decomposition of a QoS requirement is based on heuristics, the selection might fail to find composite Web services. To avoid such a failure, the tightness of a QoS requirement is defined and a workflow is determined to be partitioned according to the tightness. A mixed integer linear programming is utilized for the efficient service selection. Experimental results show that the success rate of partitioning is above 99%. Particularly, the proposed method performs faster and selects composite services whose qualities are not significantly different (less than 5%) from the optimal one.

User Integrated Authentication System using EID in Blockchain Environment (블록체인 환경에서 EID를 이용한 사용자 통합 인증 시스템)

  • Kim, Jai-Yong;Jung, Yong-Hoon;Jun, Moon-Seog;Lee, Sang-Beon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.24-31
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    • 2020
  • Centralized systems in computing environments have various problems, such as privacy infringement due to hacking, and the possibility of privacy violations in case of system failure. Blockchain, one of the core technologies for the next generation of converged information, is expected to be an alternative to the existing centralized system, which has had various problems. This paper proposes a blockchain-based user authentication system that can identify users using EID in an online environment. Existing identification (ID)/password (PW) authentication methods require users to store personal information in multiple sites, and receive and use their respective IDs. However, the proposed system can be used without users signing up at various sites after the issuing of an EID. The proposed system issues an EID with a minimum of information, such as an e-mail address and a telephone number. By comparing the stability and efficiency of a centralized system, the proposed integrated authentication system proved to be excellent. In order to compare stability against existing systems, we chose attack methods and encroachments on the computing environment. To verify efficiency, the total throughput between the user's app, the issuance and certification-authority's servers, and the service provider's servers was compared and analyzed based on processing time per transaction.

Global Market Entry Strategies of Korea-Japan Discount Stores (한.일 대형할인마트 해외진출 전략)

  • Kim, Young;Yoshimoto, Koji;Kim, Jang-Hyun;Ryu, Sung-Yong
    • Journal of Distribution Research
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    • v.15 no.5
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    • pp.195-215
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    • 2010
  • Large-scale discount stores, that were in charge of leading role up to recently, reach the limit of growth because of increasing competition, saturation of domestic market, and shortened product life-cycle. As per the limit of domestic market, large-scale discount stores are trying to various global market entry strategy and global marketing strategy like new store entry, takeover of foreign distribution chain, and global sourcing strategy. In the past, global companies of advanced country have been entering to Asian market with leading position. But, as per the rapid growth of Asian economy in the late 1980's, East Asian distribution companies like Japanese company were trying to enter the Asian market. In Asian market, starting with China, that was relatively not advanced in comparison with economic development, not only western advanced countries but also East Asian countries like Japan and Korea are entering actively for overcome their limitations of domestic market. Many of distribution companies experienced success and failure for various reason already. Korean large-scale discount stores are relatively late starters in Asian market. So, this paper purposed to review global market entry strategy of Japanese large-scale discount stores, and find out strategic implications for successful global market entry strategy of Korean large-scale discount stores.

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Case study of Journal Article and Reference Mapping (학술논문과 참고문헌의 자동매핑 사례 분석)

  • Kim, Jayhoon;Kim, Soon Young;Lim, Seok Jong;Hwang, Hyekyong
    • The Journal of the Korea Contents Association
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    • v.19 no.11
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    • pp.262-269
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    • 2019
  • References at the end of an academic paper are information that helps authors keep their research ethics, readers refer to related prior studies. Also references are useful information for linking citations and citations between articles. As bibliography metrics develops, bibliographic data is used as an important data for assessing the academic influence of countries, institutions and individual researchers. However, it is not easy to identify and link the reference data due to the diversity of the bibliographic citation formats, the loss of information due to the abbreviation of journal names and author names, and typos by authors. This study investigated the method of improving the bibliographic data mapping rate by analyzing the unmapped cases. As a result, it was found that the main cause of the article-reference mapping failure was the similarity of abbreviated journal names. Research team suggested that continuous management of journal title authority data and improving the DOI registration rate as ways to improve the identification and mapping rate. This study is differentiated from other studies in used database. Bibliography mapping was attempted for domestic and foreign integrated journal database that is mainly subscribed, used, published and cited in Korea. Through reference construction volume and mapping rate improvement, it can be used as citation analysis and service database reflecting domestic situation that is different from overseas citation index database.