• Title/Summary/Keyword: Fault Notice

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The Effect Assessment Method of Control and Protection Systems on Transient Stability of Power Systems

  • Miki, Tetsushi;Sugino, Ryuzaburou;Kono, Yoshiyuki
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.736-740
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    • 2004
  • In order to overcome the problems of simulation methods, the power system transient stability assessment method using critical fault clearing time functions has been developed. Using the above method, this paper has developed the new method which can assess accurately and efficiently the effects of control and protection systems on transient stability which is the most important characteristic to assess in power systems. At first, critical fault clearing time functions CCT(W:load) are defined by taking notice of the fact that transient stability is mainly controlled by fault clearing time and load. Next, the method to be enable to assess accurately and efficiently the effects of control and protection systems on transient stability has been newly developed by using the above functions. Finally, it has been applied to the effect assessment in the occurrence of a three-phase fault in a model power system. Results of application have been clarified its effectiveness.

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Development of Multi LED type Door Status Indication Lamp for rolling stock (Multi LED를 이용한 철도차량용 Door Status Indication Lamp)

  • Seo, Bum-Won;Choi, Jae-Sung;Kim, Dong-Il
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1668-1674
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    • 2011
  • Door Inside Lamp of railway rolling stock is installed on interior of the side doors and illuminated at door opening and closing, isolation and fault. So drivers or passengers can notice the door status visually. In the past, a single color or Bi-color LED Lamps have been using and one ~ multiple lamp was used to implement the feature according to client's requirements. (Example: Total of between 2 and 4 lamps are required for the Warning / Emergency operation / Isolation / Fault.) However these design is not easy to apply if there is the mounting space restrictions and the problems such as rising costs can be caused. In addition, it has vulnerability from point of view aesthetic aspects. Therefore the lamp type has been required that has small size and number of colors in order to resolve these problems. Recently multi LED type door status indication lamp have been developed that can meet the requirements and this lamp has been applied in many railway projects. In this study, I'll introduce the general characteristics and mechanical & electrical characteristics of multi LED type door status indication lamp to help development of this kinds of lamp.

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Development of Multi LED type Door Status Indication Lamp for rolling stock (Multi LED를 이용한 철도차량용 Door Status Indication Lamp)

  • Seo, Bum-Won;Choi, Jae-Sung;Kim, Dong-Il
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1466-1472
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    • 2011
  • Door Inside Lamp of railway rolling stock is installed on interior of the side doors and illuminated at door opening and closing, isolation and fault. So drivers or passengers can notice the door status visually. In the past, a single color or Bi-color LED Lamps have been using and one ~ multiple lamp was used to implement the feature according to client's requirements. (Example: Total of between 2 and 4 lamps are required for the Warning / Emergency operation / Isolation / Fault.) However these design is not easy to apply if there is the mounting space restrictions and the problems such as rising costs can be caused. In addition, it has vulnerability from point of view aesthetic aspects. Therefore the lamp type has been required that has small size and number of colors in order to resolve these problems. Recently multi LED type door status indication lamp have been developed that can meet the requirements and this lamp has been applied in many railway projects. In this study, I'll introduce the general characteristics and mechanical & electrical characteristics of multi LED type door status indication lamp to help development of this kinds of lamp.

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The Method of Searching Unified Medical Language System Using Automatic Modified a Query (자동 질의수정을 통한 통합의학언어 시스템 검색)

  • 김종광;하원식;이정현
    • Proceedings of the IEEK Conference
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    • 2003.11b
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    • pp.129-132
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    • 2003
  • The metathesaurus(UMLS, 2003AA edition) supports multi language and includes 875, 233 concepts, 2, 146, 897 concept names. It is impossible for PubMed or NLM serve searching of the metatheaurus to retrieval using a query that is not to be text, a fault sentence structure or a part of concept name. That means the user notice correctly suitable medical words in order to get correct answer, otherwise she or he can't find information that they want to find I propose that the method of searching unified medical language system using automatic modified a query for problem that I mentioned. This method use dictionary that is standard for automation of modified query gauge similarity between query and dictionary using string comparison algorithm. And then, the tested term converse the form of metathesaurus for optimized result. For the evaluation of method, I select some query and I contrast NLM method that renewed Aug. 2003.

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Implementaion Mechanism of Homepage Failure Notification System in Public Sector in IDC Environment (IDC환경에서 공공부문 홈페이지 장애상황공지 시스템 구축방안)

  • Kim, Yong-Tae;Jo, In-June
    • The Journal of the Korea Contents Association
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    • v.21 no.1
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    • pp.426-433
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    • 2021
  • Investment in public sector information services has been on the rise in recent years. The supply of high-speed Internet and smartphones has become more common, and the stability of the information system provided to the public in the public sector has become an important management factor. In other words, tasks such as handling civil complaints and issuing certificates by public institutions, financial transactions by banks, customs clearance work, and e-commerce by individuals or institutions are mostly done online. Therefore, how to deal with obstacles arising from the information system, which is in charge of important civil service affairs, is becoming a very important issue. In other words, in the case of a disability that does not function normally even for a short period of time, various problems can occur when the work is delayed, as well as causing serious financial damage to the civil petitioner. This could be accompanied by a decline in public confidence and various other damages such as filing civil complaints. The reasons for the occurrence of information system failures are very diverse and realistically difficult to predict when. Among the various measures to cope with disability, this paper proposed a plan to establish a disability situation notification system that can minimize confusion caused by disability in the event of a homepage malfunction. The proposed disability situation notification system was established in the public IDC environment to show the possibility of utilization.

An Optimal Peer Selection Algorithm for Mesh-based Peer-to-Peer Networks

  • Han, Seung Chul;Nam, Ki Won
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.1
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    • pp.133-151
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    • 2019
  • In order to achieve faster content distribution speed and stronger fault tolerance, a P2P peer can connect to multiple peers in parallel and receive chunks of the data simultaneously. A critical issue in this environment is selecting a set of nodes participating in swarming sessions. Previous related researches only focus on performance metrics, such as downloading time or the round-trip time, but in this paper, we consider a new performance metric which is closely related to the network and propose a peer selection algorithm that produces the set of peers generating optimal worst link stress. We prove that the optimal algorithm is practicable and has the advantages with the experiments on PlanetLab. The algorithm optimizes the congestion level of the bottleneck link. It means the algorithm can maximize the affordable throughput. Second, the network load is well balanced. A balanced network improves the utilization of resources and leads to the fast content distribution. We also notice that if every client follows our algorithm in selecting peers, the probability is high that all sessions could benefit. We expect that the algorithm in this paper can be used complementary to existing methods to derive new and valuable insights in peer-to-peer networking.

MITM Attack on Bluetooth Pairing in Passkey Entry Mode and Its Countermeasure (블루투스 Passkey Entry 인증 모드에 대한 MITM 공격과 대응방법)

  • Lee, Jearyong;Choi, Wonsuk;Lee, DongHoon
    • KIPS Transactions on Computer and Communication Systems
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    • v.5 no.12
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    • pp.481-490
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    • 2016
  • Bluetooth utilizes a symmetric key that is exchanged at the first pairing to establish a secure channel. There are four authentication modes which enables device authentication, Just work, Passkey Entry, Out of Band, and Numeric Comparison. Up to now, Just work has been considered as the authentication mode that is vulnerable to Man-In-The-Middle (MITM) Attack. In addition, it is possible to intentionally change any authentication mode to Just work mode, in order to succeed in MITM Attack under Just work mode. However, this kind of attacks have just worked under the assumption that users should not notice that authentication mode was changed. In this paper, We analyze the specification of Secure Simple Pairing, LE Legacy Pairing and LE Secure Connection Pairing. When using Passkey Entry mode on each approach, it seems the MITM attack is possible. Also it offers Passkey Entry MITM attack that does not require assumptions about the user's fault, because it isn't change verification process of the authentication mode unlike traditional attacks. We implement the proposed MITM attacks. Also we presents a scenario in which an attack can be exploited and a countermeasure.

Proposed Survey Steps for Investigation of Land-Creeping Susceptibility Areas: A Focus on Geophysical Mapping of the Yongheung-dong, Pohang, Korea

  • Kim, Jeong-In;Lee, Sun-Joong;Kim, Kwan-Soo;Lee, Jae-Eun;Sa, Jin-Hyun;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.31 no.3
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    • pp.269-281
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    • 2021
  • Land creeping is the imperceptibly slow, steady, downward movement o f slope-forming soil or rock. Because creep-related failures occur frequently on a large scale without notice, they can be hazardous to both property and human life. Korea Forest Service has operated the prevention and response system from land creeping which has been on the rise since 2018. We categorized and proposed three survey steps (e.g., preliminary, regional, detailed) for investigation of creeping susceptibility site with a focus on geophysical mapping of a selected test site, Yongheung-dong, Pohang, Korea. The combination of geophysical (dipole-dipole electrical resistivity tomography and reciprocal seismic refraction technique, well-logging), geotechnical studies (standard penetrating test, laboratory tests), field mapping (tension cracks, uplift, fault), and comprehensive interpretation of their results provided the reliable information of the subsurface structures including the failure surface. To further investigate the subsurface structure including the sliding zone, we performed high-resolution geophysical mapping in addition to the regional survey. High-resolution seismic velocity structures are employed for stability analysis because they provided more simplified layers of weathering rock, soft rock, and hard rock. Curved slip plane of the land creeping is effectively delineated with a shape of downslope sliding and upward pushing at the apex of high resistive bedrock in high-resolution electrical resistivity model with clay-mineral contents taken into account. Proposed survey steps and comprehensive interpretation schemes of the results from geological, geophysical, and geotechnical data should be effective for data sets collected in a similar environment to land-creeping susceptibility area.

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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