• Title/Summary/Keyword: service failure

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Consistent Distributed Lookup Service Architecture for Mobile Ad-hoc Networks

  • Malik Muhammad Ali;Kim Jai-Hoon
    • International Journal of Contents
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    • v.2 no.2
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    • pp.29-31
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    • 2006
  • Mobile Ad hoc network is a self configuring network of mobile nodes. It allows mobile nodes to configure network spontaneously and share their services. In these networks, service discovery is very important because all nodes do not have same resources in term of memory and computing power. Nodes need to use different services offered by different servers. Some service discovery protocols have been proposed in last couple of years but they include significant traffic overhead and for small scale MANETS. In this paper, we present extensible lookup service scheme based on distributed mechanism. In our scheme neighboring nodes of service provider monitor service provider and send notification to lookup server when the service provider terminates its services unexpectedly. Lookup server can find other service provider or other alternative services in advance because of advance notification method and can provide consistent lookup services. In our scheme neighboring nodes also monitor lookup server and send notification to network when lookup server terminates unexpectedly. Simulation results show that our scheme can reduce up to 70% and 30% lookup failure as compare to centralize and simple distributed mechanism respectively.

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Failure Pressure Prediction of Composite Cylinders for Hydrogen Storage Using Thermo-mechanical Analysis and Neural Network

  • Hu, J.;Sundararaman, S.;Menta, V.G.K.;Chandrashekhara, K.;Chernicoff, William
    • Advanced Composite Materials
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    • v.18 no.3
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    • pp.233-249
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    • 2009
  • Safe installation and operation of high-pressure composite cylinders for hydrogen storage are of primary concern. It is unavoidable for the cylinders to experience temperature variation and significant thermal input during service. The maximum failure pressure that the cylinder can sustain is affected due to the dependence of composite material properties on temperature and complexity of cylinder design. Most of the analysis reported for high-pressure composite cylinders is based on simplifying assumptions and does not account for complexities like thermo-mechanical behavior and temperature dependent material properties. In the present work, a comprehensive finite element simulation tool for the design of hydrogen storage cylinder system is developed. The structural response of the cylinder is analyzed using laminated shell theory accounting for transverse shear deformation and geometric nonlinearity. A composite failure model is used to evaluate the failure pressure under various thermo-mechanical loadings. A back-propagation neural network (NNk) model is developed to predict the maximum failure pressure using the analysis results. The failure pressures predicted from NNk model are compared with those from test cases. The developed NNk model is capable of predicting the failure pressure for any given loading condition.

The Failure Mode and Effects Analysis Implementation for Laser Marking Process Improvement: A Case Study

  • Deng, Wei-Jaw;Chiu, Chung-Ching;Tsai, Chih-Hung
    • International Journal of Quality Innovation
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    • v.8 no.1
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    • pp.137-153
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    • 2007
  • Failure mode and effects analysis (FMEA) is a preventive technique in reliability management field. The successful implementation of FMEA technique can avoid or reduce the probability of system failure and achieve good product quality. The FMEA technique had applied in vest scopes which include aerospace, automatic, electronic, mechanic and service industry. The marking process is one of the back ends testing process that is the final process in semiconductor process. The marking process failure can cause bad final product quality and return although is not a primary process. So, how to improve the quality of marking process is one of important production job for semiconductor testing factory. This research firstly implements FMEA technique in laser marking process improvement on semiconductor testing factory and finds out which subsystem has priority failure risk. Secondly, a CCD position solution for priority failure risk subsystem is provided and evaluated. According analysis result, FMEA and CCD position implementation solution for laser marking process improvement can increase yield rate and reduce production cost. Implementation method of this research can provide semiconductor testing factory for reference in laser marking process improvement.

An Analysis on System Failure Mechanism of Sectoral Innovation Systems (SIS) : The Case of Mobile Internet Industry in Korea (무선인터넷서비스 산업혁신시스템 실패 메커니즘의 분석)

  • Lee, Kyoung-Ae
    • Journal of Korea Technology Innovation Society
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    • v.11 no.1
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    • pp.46-71
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    • 2008
  • Although the volume of mobile internet services has increased continually over the years, the rapid diffusion has still fallen short of expected quality. This paper considers mobile internet service industry in Korea as a system failure due to structural problems and attempts to identify systemic imperfection mechanisms from the supply side. The problems of mobile internet industry in Korea are categorized into interaction failures, institutional failures and capabilities failures which contribute to system failure and at the same time, failure types are linked to each other. It is needed to improve policy and institutions in operation and develop new policy for contents providers to promote mobile internet industry. This research findings will contribute to policy making to promote mobile internet service industry and development of sectoral system for emerging industries.

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Differential Effects of Recovery Efforts on Products Attitudes (제품태도에 대한 회복노력의 차별적 효과)

  • Kim, Cheon-GIl;Choi, Jung-Mi
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.1
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    • pp.33-58
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    • 2008
  • Previous research has presupposed that the evaluation of consumer who received any recovery after experiencing product failure should be better than the evaluation of consumer who did not receive any recovery. The major purposes of this article are to examine impacts of product defect failures rather than service failures, and to explore effects of recovery on postrecovery product attitudes. First, this article deals with the occurrence of severe and unsevere failure and corresponding service recovery toward tangible products rather than intangible services. Contrary to intangible services, purchase and usage are separable for tangible products. This difference makes it clear that executing an recovery strategy toward tangible products is not plausible right after consumers find out product failures. The consumers may think about backgrounds and causes for the unpleasant events during the time gap between product failure and recovery. The deliberation may dilutes positive effects of recovery efforts. The recovery strategies which are provided to consumers experiencing product failures can be classified into three types. A recovery strategy can be implemented to provide consumers with a new product replacing the old defective product, a complimentary product for free, a discount at the time of the failure incident, or a coupon that can be used on the next visit. This strategy is defined as "a rewarding effort." Meanwhile a product failure may arise in exchange for its benefit. Then the product provider can suggest a detail explanation that the defect is hard to escape since it relates highly to the specific advantage to the product. The strategy may be called as "a strengthening effort." Another possible strategy is to recover negative attitude toward own brand by giving prominence to the disadvantages of a competing brand rather than the advantages of its own brand. The strategy is reflected as "a weakening effort." This paper emphasizes that, in order to confirm its effectiveness, a recovery strategy should be compared to being nothing done in response to the product failure. So the three types of recovery efforts is discussed in comparison to the situation involving no recovery effort. The strengthening strategy is to claim high relatedness of the product failure with another advantage, and expects the two-sidedness to ease consumers' complaints. The weakening strategy is to emphasize non-aversiveness of product failure, even if consumers choose another competitive brand. The two strategies can be effective in restoring to the original state, by providing plausible motives to accept the condition of product failure or by informing consumers of non-responsibility in the failure case. However the two may be less effective strategies than the rewarding strategy, since it tries to take care of the rehabilitation needs of consumers. Especially, the relative effect between the strengthening effort and the weakening effort may differ in terms of the severity of the product failure. A consumer who realizes a highly severe failure is likely to attach importance to the property which caused the failure. This implies that the strengthening effort would be less effective under the condition of high product severity. Meanwhile, the failing property is not diagnostic information in the condition of low failure severity. Consumers would not pay attention to non-diagnostic information, and with which they are not likely to change their attitudes. This implies that the strengthening effort would be more effective under the condition of low product severity. A 2 (product failure severity: high or low) X 4 (recovery strategies: rewarding, strengthening, weakening, or doing nothing) between-subjects design was employed. The particular levels of product failure severity and the types of recovery strategies were determined after a series of expert interviews. The dependent variable was product attitude after the recovery effort was provided. Subjects were 284 consumers who had an experience of cosmetics. Subjects were first given a product failure scenario and were asked to rate the comprehensibility of the failure scenario, the probability of raising complaints against the failure, and the subjective severity of the failure. After a recovery scenario was presented, its comprehensibility and overall evaluation were measured. The subjects assigned to the condition of no recovery effort were exposed to a short news article on the cosmetic industry. Next, subjects answered filler questions: 42 items of the need for cognitive closure and 16 items of need-to-evaluate. In the succeeding page a subject's product attitude was measured on an five-item, six-point scale, and a subject's repurchase intention on an three-item, six-point scale. After demographic variables of age and sex were asked, ten items of the subject's objective knowledge was checked. The results showed that the subjects formed more favorable evaluations after receiving rewarding efforts than after receiving either strengthening or weakening efforts. This is consistent with Hoffman, Kelley, and Rotalsky (1995) in that a tangible service recovery could be more effective that intangible efforts. Strengthening and weakening efforts also were effective compared to no recovery effort. So we found that generally any recovery increased products attitudes. The results hint us that a recovery strategy such as strengthening or weakening efforts, although it does not contain a specific reward, may have an effect on consumers experiencing severe unsatisfaction and strong complaint. Meanwhile, strengthening and weakening efforts were not expected to increase product attitudes under the condition of low severity of product failure. We can conclude that only a physical recovery effort may be recognized favorably as a firm's willingness to recover its fault by consumers experiencing low involvements. Results of the present experiment are explained in terms of the attribution theory. This article has a limitation that it utilized fictitious scenarios. Future research deserves to test a realistic effect of recovery for actual consumers. Recovery involves a direct, firsthand experience of ex-users. Recovery does not apply to non-users. The experience of receiving recovery efforts can be relatively more salient and accessible for the ex-users than for non-users. A recovery effort might be more likely to improve product attitude for the ex-users than for non-users. Also the present experiment did not include consumers who did not have an experience of the products and who did not perceive the occurrence of product failure. For the non-users and the ignorant consumers, the recovery efforts might lead to decreased product attitude and purchase intention. This is because the recovery trials may give an opportunity for them to notice the product failure.

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An Outage Evaluation Model for Wireless Telecommunication Network (무선통신망의 장애영향 평가 모델)

  • Lee, Dong-Hoon;Chong, Il-Young
    • The KIPS Transactions:PartC
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    • v.10C no.1
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    • pp.111-118
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    • 2003
  • Network reliability means network ability which perform normal operation of network components within defined time period, on the other hand, network survivability is the index of normal operation in nerwork failure. In occurrence of network failure, network operator is interested in the measurement of network survivability, but, in a view of subscribers, it is more interested in how many subscribers are out of service and how long the out of service state lasts. In this paper, a service outage evaluation model fitted for telecommunication network in Korea is proposed, which measures the impacts of subscribers in case of network failure which induces a service outage. The outage evaluation result of "Mobile to Land" service outage which has 30.000 subscribers affected for 30 minutes is 2.5. This value is 5 times larger than that of the same service outage which has 10,000 subscribers affected for 30 minutes, i.e, the impact of subscribers in the former case is 5 times larger than that of the latter case. If 30,000 subscribers have isolated in "Mobile to Land," "Local Mobile to Mobile" service for 30 minutes by the exchange out of order in PCS network, then the evaluation result of this service outage will be 3.75.

Evaluation of Reference Service for Korean Government Publications (한국 정부간행물 참고서비스의 질측정에 관한 연구)

  • Kim Young Shin
    • Journal of the Korean Society for Library and Information Science
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    • v.23
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    • pp.127-163
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    • 1992
  • The proper evaluation of reference services requires qualitative approach as well as quantitative one. The quality of a reference service can be evaluated by how promptly and accurately a librarian responds to the user's questions and also by how much the user is satisfied with the librarian's overall performance in providing the answer. In this study, the reference service of an university library was evaluated by the following procedure : 1. Identification of a group of the most frequently referred Korean government publications through two pre-tests of user surveys. 2. Preparation of 130 questions of bibliographic and factual type from the above publications. 3. Selection of 30 questions which can be answered from the collection of the evaluated library. 4. Mimic requests of reference service by 5 proxies trained on the unobtrusive test method with 30 questions asked at various times of the day and on various days of the week during a period of 5 months. 5. Drawing up of response sheets (by proxies) with descriptive comments on library staffs' question administration, response, attitude, etc. 6. Preparation and coding of data tabulation sheets and final analysis. The conclusions of this study are as follows : 1. The user serveys showed that needs for the library service for government publications were great. The $80\%$ of the government publications users were visiting more than two organizations for access to information and the $37\%$ were getting information directly from the publishers. 2. The librarians of the evaluated library could give correct answers to $53\%$ of 30 (bibliographic and factual) guestions. 3. The correctness of answer was independent of the length of the time spent the librarians. The librarians' grasp of the questions and direction of approach determined the success or failure of the service. 4. The librarians relied too much on the reference library catalog which doesn't include many of the government publications of their own collection. 5. The $79\%$ of the failure of the service were due to the librarians' lack of knowledge as to the information source for government publications and the unsystematic method of approach to it.

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An Autonomic -Interleaving Registry Overlay Network for Efficient Ubiquities Web Services Discovery Service

  • Ragab, Khaled
    • Journal of Information Processing Systems
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    • v.4 no.2
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    • pp.53-60
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    • 2008
  • The Web Services infrastructure is a distributed computing environment for service-sharing. Mechanisms for Web services Discovery proposed so far have assumed a centralized and peer-to-peer (P2P) registry. A discovery service with centralized architecture, such as UDDI, restricts the scalability of this environment, induces performance bottleneck and may result in single points of failure. A discovery service with P2P architecture enables a scalable and an efficient ubiquities web service discovery service that needs to be run in self-organized fashions. In this paper, we propose an autonomic -interleaving Registry Overlay Network (RgON) that enables web-services' providers/consumers to publish/discover services' advertisements, WSDL documents. The RgON, doubtless empowers consumers to discover web services associated with these advertisements within constant D logical hops over constant K physical hops with reasonable storage and bandwidth utilization as shown through simulation.

A Research on the Development of Management Process System of Public Ordering Service Results and Estimation (건설기술용역 실적 관리 프로세스 시스템 개발에 대한 연구)

  • Lee, Kyu-Sung;Lee, Han-kyu;Kim, Nam-Gon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.168-169
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    • 2014
  • Construction Technology Service is currently hardly managed due to failure to offer standard management system of service performance, company performance, and business evaluation in every Ordering Agencies. After Construction Technology Promotion Act is enforced in May 2014, Ordering Agency obligates them to report to Minister of Land and Transportation within 10 days upon contract/ amendment/ completion. In 2013, in advance to enforcement of this law, performance management system for construction technology service was developed for a test run. However this system only applies to main contractors while management and operation of subcontractors are unavailable that causes problems on connection and integration with Experience Management Trustee. Therefore, this research will establish systematic foundation that enables real-time information of service performance and evaluation of subcontractors to result standardization of performance and evaluation for public ordered services.

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A Study on the Influencing Factors on the Profit Improvement Rate of IT Service Projects (IT서비스 프로젝트의 이익개선율 영향요인에 관한 연구)

  • Lee, Kyung-Bae;Oh, Jay-In
    • Journal of Information Technology Applications and Management
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    • v.17 no.4
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    • pp.127-156
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    • 2010
  • Most companies in the IT service industry have suffered from low profitability although this industry is highly value added, which may result in losing the competitiveness of the industry. The purpose of this study is to identify the influencing factors on the profit improvement rate of IT service projects and suggest how to improve the profit improvement rate, thus recovering the competitiveness of the IT service industry. The 273 IT service projects conducted by an IT service company in Korea during the past three years were analyzed and the project managers who performed these projects responded to the questionnaire developed in this study. The result from the analysis of data collected shows that the influencing factors on the profit improvement rate of IT service projects include scheduling, experience in similar projects, the leadership of project leaders, the level of team skills, relationship with clients, and clients support.

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