• 한국신뢰성학회지:신뢰성응용연구
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• 제6권4호
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• pp.275-284
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• 2006

A test method for assessing service life of building materials and components based on performance degradation data is developed. The performance of a building material degrades as time goes by and the failure of the material is often defined as the point at which the performance of the material reaches a pre-specified degraded level. A performance-based test method is developed and a numerical example is provided to illustrate the use of the developed test method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 춘계종합학술대회
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• pp.61-64
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• 2007

MPLS 네트워크에서 QoS(Duality of Service)에 관한 요구가 증대함에 따라 확장성을 보장하고 장애 복구를 위한 다중 경로 계산 방안들에 관한 여러 기술들이 제시되고 있다. 그러나 MPLS 네트워크는 트래픽에 관한 확장성 문제와 기존의 장애 복구 방식들의 경우 자원 낭비와 많은 지연 발생으로 인한 손실이 발생하는 문제점이 있다. 따라서 본 연구에서는 LSP 다중경로 라우팅 알고리즘을 적용한 망의 효율적인 관리 및 신속한 장애 복구를 위해 H-MPLS(Hierachical-Multiprotocol Label Switching) 네트워크 제안한다. 또한 확장된 규모의 망을 계층형 MPLS로 구성하여 기존의 장애복구 방식을 다양한 네트워크 모델로 적용하고, 이를 NS 시뮬레이터를 통해 성능 분석하여 그 효율성 및 확장성의 개선방안을 제시하고자 한다.

• 산업공학
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• 제12권1호
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• pp.1-9
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• 1999

This paper presents a method for reliability analysis of the air-conditioner with service data. We explain how to acquire and analyze the service data and some problems in data analysis. We propose two procedures to analyze reliability of air-conditioner using operating time concept and predict the operating times by temperature and failure frequency. Finally, the prediction method for future service is studied by numerical example.

• Journal of Multimedia Information System
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• 제7권1호
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• pp.55-72
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• 2020

As the IT service environment grows, it is critical in terms of IT service quality to minimize the occurrence of failures due to changes in applications and to diagnose and recover in a short period of time how failure will affect the business. Thus, the Defense Acquisition Program Administration (DAPA) has been building and operating ITSMs to implement IT service management in a leading manner. Information Technology Service Management (ITSM) is divided into events, obstacles, changes, versions and setup management to ensure flexibility and stability in service delivery. It is also operated separately from service level, availability, capacity, financial and IT service continuity management to ensure service quality and cost efficiency. Based on ITSM military service history, this study looks at the impact of quality of service on value, satisfaction, and trust. The results of the analysis are highly valuable for future ITSM implementation and operation.

• 한국IT서비스학회지
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• 제19권1호
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• pp.129-144
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• 2020

Recent advances in digital purchase platforms allow consumer to easy to access online purchase, but the online purchase systems often occurs a negative situations such as service failure. When customer experiences negative service, they want to communicate with the company online chatting service. But not much is known about how customers online chatting service's contextual cues effectiveness. So, the current research seeks to examine the effects of type of online chatting service interface and company market status on customers' perception of service quality and satisfaction with online chatting services. The results of two studies show that, when customer experienced negative online service, they expected to a high status (vs a low status) company had offered better service. but their service request are not met, customers perceive better service quality if served by a low status (vs high status) company represented by a logo (vs. an emoji). These findings will help marketing practitioners strategically how design their chatting service interface according to the their status when they communicate with customer who experienced negative service.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.73-76
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• 2006

International Roaming is a kind of telecommunication service that enables subscribers use the same mobile number when they go abroad and access other service provider's network. International roaming call is made through three network parts-home (original service provider) network, intermediate network, and local (overseas service provider) network. It is not possible to monitor every section of whole roaming service network because service providers do not provide their network management information to other service providers. The limitation causes harsh problem when a service anomaly arises and operators have to confirm the reason of failure. To solve this problem, we propose a scheme that deduces roaming service status of each overseas service provider using internal network management information. SK telecom implemented a international roaming service management system based on the scheme using performance measurement of signaling points, roaming service nodes, and charging data from existing network management systems.

• 열처리공학회지
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• 제27권4호
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• pp.191-201
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• 2014

The gear was made of SNC815 case-carburized, quench hardened and tempered steel. The gears were failed far earlier than the expected service life used in the industrial site. Causes of the failed gear were analyzed by microstructure observation. By the SEM and micro structure examinations, the damaged surfaces had been weared and failed by fatigue. Through microscope observation on the damaged surface, it was found that the cause of failure was determined by external overloading and the initial stage of the damage was closely related to complex contact fatigue failure. The overload and contact fatigue contributed to the early failure cause.

• Structural Engineering and Mechanics
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• 제81권1호
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• pp.59-68
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• 2022

Prestressed prefabricated hollow core concrete slabs with spans of 5 m and 10 m are commonly used since last century and still in service due to the advantage of construction convenience and durability. However, the end slabs are regularly subjected to cracks at the top and fail with brittleness due to the asymmetric boundary conditions. To better maintain such widely used type of hollow core slabs, the effect of asymmetric constraint in the end slabs are systematically studied through detailed nonlinear finite element analyses and experimental data. Experimental tests of slabs with four prestressed tendons and seven prestressed tendons with different boundary conditions were conducted. Results observe three failure modes of the slabs: the bending failure mode, shear and torsion failure mode, and transverse failure mode. Detailed nonlinear finite element models are developed to well match the failure modes and to reveal potential damage scenarios with asymmetric boundary conditions. Recommendations regarding ultimate capacity of the slabs with asymmetric boundary conditions are made to ensure a safe and rational design of prestressed concrete hollow slabs for short span bridges.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.617-621
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• 2003

The purpose of this paper is to analyze piping failure trend of safety pipings In domestic nuclear power plants. First, database for the piping failure was constructed with 105 data fields. The database includes plant population data, event data, and service history data. 7 kinds of piping failures in domestic NPPs were investigated. Among the 7 cases, detailed root causes were investigated for 3 cases. The first one is pipe wall thinning in main feedwater pipings of Westinghouse 3 loop type plants. The root cause of the wall thinning was flow accelerated corrosion near welding area. The next one is leak event in chemical and volume control system(CVCS) due to vibration. Some cracks occurred in socket welding area. The events showed that the integrity or socket weld is very vulnerable to vibration. The last one is also a leak event in primary sampling line in Korean standard reactor due to thermal fatigue. Although the structural integrity was not maintained by the events, there was no effect on nuclear safety in the above 3 piping failure eases.

• 품질경영학회지
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• 제38권4호
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• pp.593-600
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• 2010

This study aims to explore the service activities in the aircraft cabin service, develop the service process structure, and design a more efficient service delivery system in Korean airline industry. We prepare the architectural drawings of the basic components in providing the cabin service using the service blueprint technique and service process perspective. Through the case study largely based on our own research and long-time work experiences in the airline industry, we propose service failure points as well as customer waiting points. This study will be helpful for managers at all levels to use the service blueprint strategically or at a shop-floor level and improve their cabin service quality.