• Journal of Information Processing Systems
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• 제2권1호
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• pp.6-12
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• 2006

Peer-to-Peer (P2P) networks are attracting considerable research interest because of their scalability and high performance relative to cost. One of the important services on a P2P network is the streaming service. However, because each node in the P2P network is autonomous, it is difficult to provide a stable streaming service on the network. Therefore, for a stable streaming service on the P2P network, a fault-tolerant scheme must be provided. In this paper, we propose two new node selection schemes, Playback Node First (PNF) and Playback Node first with Prefetching (PNF-P) that can be used for a service migration-based fault-tolerant streaming service. The proposed schemes exploit the fact that the failure probability of a node currently being served is lower than that of a node not being served. Simulation results show that the proposed schemes outperform traditional node selection schemes.

• 품질경영학회지
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• 제35권4호
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• pp.61-66
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• 2007

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. Based on a stochastic deterioration model, a performance based service life prediction method for building materials and components is developed. As a stochastic degradation model, a gamma process is considered and lifetime distribution and service life of a material are predicted using the degradation model. A numerical example is provided to illustrate the use of the proposed service life prediction method.

• 한국조리학회지
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• 제11권4호
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• pp.198-213
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• 2005

This study was administered to demonstrate how unsatisfied customers would be influenced by the change in the quality of the service delivered to them after the dissatisfaction occurs. In light of the above, the objective of this study is to find out what leads to dissatisfaction in the minds of the consumers and also to identify the common behavioral patterns indicated by unsatisfied consumers. This study consists of two parts: a research based on the review of the literature and empirical study methods. As a result, a research for the popular forms of complaining patterns shows opportunities for restaurants to come up with measures to improve their service quality when customers are unsatisfied. In service recovery situation, distributive and interactional justice significantly influence customers' repurchase. Therefore, firms ought to offer monetary compensation, explain about the problems, and make their best efforts to recover the failure because the efforts also affect repurchase.

• 정보화연구
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• 제9권2호
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• pp.133-142
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• 2012

Gartner predicts that by 2012, 40% of EA programs will be stopped due to poor execution and the failure of delivering business value. An organization needs a practical solution to achieve an EA vision. The EA essential approach should be that of business service and process orientation than systems and IT orientation. We propose an Actionable Enterprise Architecture (AEA) which is based on BPM (Business Process Management) and SOA (Service Oriented Architecture), and connected to service & process orientation and engineering. The architecture proposed provides traceability between service-oriented enterprise architecture and its solution. The proposed architecture can transform enterprise architecture from conceptual to physical levels (solutions) with a service and business process paradigm.

• 한국컴퓨터정보학회논문지
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• 제20권6호
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• pp.29-35
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• 2015

The heterogeneous LTE (Long Term Evolution)-Advanced networks comprising a macrocell and femtocells can provide an efficient solution not only to extend macrocell coverage but also to deal with packet traffics increasing explosively within macrocells. An efficient resource management scheme is necessary to maintain the QoS (Quality of Service) of mobile multimedia services because the LTE-Advanced system should support not only voice but also mobile applications such as data, image and video. This paper proposes a resource management scheme to guarantee QoS continuity of multimedia services and to maximize the resource utilization in OFDMA (Orthogonal Frequency Division Multiple Access) based LTE-Advanced systems. This scheme divides the resources into several service blocks and allocates those resources based on the competition between macrocell and femtocell. Simulation results show that it provides better performances than the conventional one in respect of handover failure rate and blocking rate.

• 품질경영학회지
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• 제34권4호
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• pp.78-92
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• 2006

While many services appear, it are performed in the various researches about a service. Among them, as to the basic reason for measuring the service level, in order to find out the strategy improving service quality. But the method for measuring quality of services up to date was unable to make it enough the role. This research tried to propose the approach systematically analyzing the human errors in order to improve service quality about the call center which utilizes the information technology. In fact, the human errors was found in the customer contact point in which the actual service is delivered. An interaction between the element for comprising call service was classified into 3 while defining the human error as 3 group. Moreover, the process where a service is delivered was classified according to 5 step and the generated error was measured in each step. The implication of this research looks at the service failure and dissatisfaction as the occurrence of the human errors and illustrates the service quality improvement as a correction or a reduction. This approach is used that service is materially easily understood and is formulated with the quality improvement strategy.

• Corrosion Science and Technology
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• 제4권4호
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• pp.147-154
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• 2005

The creep resistance of geogrids is one of the most significant long-term safety characteristics used as the reinforcement in slopes and embankments. The failure of geogrids is defined as creep strain greater than 10%. In this study, the accelerated creep tests were applied to polyester geogrids at various loading levels of 30, 50% of the yield strengths and temperatures using newly designed test equipment. Also, the new test equipment permitted the creep testing at or above glass transition temperature($T_g$) of 75, 80, $85^{\circ}C$. The time-dependent creep behaviors were observed at various temperatures and loading levels. And then the creep curves were shifted and superposed in the time axis by applying time-temperature supposition principles. The shifting factors(AFs) were obtained using WLF equation. In predicting the lifetimes of geogrids, the underlying distribution for failure times were determined based on identification of the failure mechanism. The results confirmed that the failure distribution of geogrids followed Weibull distribution with increasing failure rate and the lifetimes of geogrids were close to 100 years which was required service life in the field with 1.75 of reduction factor of safety. Using the newly designed equipment, the creep test of geogrids was found to be highly accelerated. Furthermore, the time-temperature superposition with the newly designed test equipment was shown to be effective in predicting the lifetimes of geogrids with shorter test times and can be applied to the other geosynthetics.

• 한국항공운항학회지
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• 제24권1호
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• pp.33-40
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• 2016

ROK issued its first type certificate to the KC-100 airplane, Part 23 normal category, and become the State of Design (SoD) in 2013. Before this, ROK aviation regulations were focused on the operation and continued airworthiness of aircraft registered and operated in ROK that were designed and manufactured in another contracting state. Therefore the implementation of reporting system were restricted to gather the failure and service difficulty reports from the owners or operators and transmit the information to the State of Design and/or the manufacture relating to the type certificated aircraft. However, ROK, to fulfill the accountability of the State of Design, has to ensure there is a system to address the information received from the State of Registry on failure, malfunctions, defects and other occurrences that might cause adverse effects on the continuing airworthiness of the korean type certificated aircraft. This paper presents an overview of ICAO requirements for the State of Design, and current implementation of reporting system of USA and Japan and discusses the current status and further considerations on the rule-making for the malfunction, defect and failure reporting system applicable to the korean indigenous aircraft.

• 시스템엔지니어링학술지
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• 제10권1호
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• pp.43-48
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• 2014

The door system for railway vehicles is the critical device directly influences on safety and satisfaction of passengers, Recently, electrical type of passenger door system is widely used for EMU type train instead of pneumatic type of passenger door system. The estimation of MTBF and failure rates for electrical type door system is essential. The manufacturor simply provides intrinsic reliability data for the railway operator. But actual reliability data based on operation and maintenance data is not complying with intrinsic reliability. In this study, operation and failure data associated with electrical door system were analyzed in order to determine actual MTBF and failure data. Intrinsic reliability data and service reliability data were studied to finallize much more practical and reliable actual reliability. Relax 2011 was used to predict intrinsic reliability and 217Plus model was also used to estimate of actual reliability data based on field data. Furthermore, it is necessary to keep studying on reliability prediction methodology and applying it in the field and doing research on improvement of reliability through feedback as well.

• 지식경영연구
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• 제16권2호
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• pp.91-111
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• 2015

Social media marketing has gained attention from marketers due to the growing number of social media users. Marketers around the globe have a serious concern over how to utilize social media as a successful marketing tool. Many of them show a lack of understanding of the essential feature of social media and effective social media marketing strategies, which brings about a higher chance of social media marketing failures. Analyzing the failure cases of social media marketing is vital because it provides rich insights for marketing experts who have difficulty in developing effective social media marketing strategies. Therefore, this study conducted multiple case studies by selecting five failure cases of social media marketing which we defined as paradigmatic social media marketing failures which happened in the last five years in South Korea. From the case studies, we derived five successful social media marketing strategies. This study has a theoretical implication because it is the first to suggest effective social media marketing strategies based on the analysis on social media marketing failure cases. It also has a practical implication since it proposes specific social media marketing strategies which can help facilitate successful social media marketing.