• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.210-215
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• 2003

At present, communication network for subway is making use of the train radio system for main network and normally established a base station every three subway station. It is talk over the telephone between a locomotive and the traffic control for careful train service. Besides, mobile telephone equipment is using for service improve and convenience to passengers such as 011, 016, 017, 019 and what not. However, the train radio system has been occurring a various problems when a state of emergency because it is able to compose only one communication route each base station zone. We could have improving like this problems through induce the TRS(Trunked Radio System), though because have been able to compose multilateral communication route in case of linking with LCX(Leaked Coaxial) cable which is established. Therefore, we could be able to a fitting meet the emergency as train firing etc.. and efficient use of limited frequency resources.

• Structural Engineering and Mechanics
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• 제17권1호
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• pp.29-50
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• 2004

A total life model was developed to assess the service life of aging aircraft. The primary focus of this paper is the development of crack growth life projection using the response surface method. Crack growth life projection is a necessary component of the total life model. The study showed that the number of load cycles N needed for a crack to propagate to a specified size can be linearly related to the geometric parameter, material, and stress level of the component considered when all the variables are transformed to logarithmic values. By the Central Limit theorem, the ln N was approximated by Gaussian distribution. This Gaussian model compared well with the histograms of the number of load cycles generated from simulated crack growth curves. The outcome of this study will aid engineers in designing their crack growth experiments to develop the stochastic crack growth models for service life assessments.

• Journal of Communications and Networks
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• 제7권1호
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• pp.87-92
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• 2005

This paper presents basic queueing analysis contributing to teletraffc theory, with commonly accessible mathematical tools. This paper studies queueing systems with bulk arrivals. It is assumed that the number of arrivals and the expected number of arrivals in each bulk are bounded by some constraints B and (equation omitted), respectively. Subject to these constraints, convexity argument is used to show that the bulk-size probability distribution that results in the worst mean queue performance is an extremal distribution with support {1, B} and mean equal to A. Furthermore, from the viewpoint of security against denial-of-service attacks, this distribution remains the worst even if an adversary were allowed to choose the bulk-size distribution at each arrival instant as a function of past queue lengths; that is, the adversary can produce as bad queueing performance with an open-loop strategy as with any closed-loop strategy. These results are proven for an arbitrary arrival process with bulk arrivals and a general service model.

• Journal of Information Processing Systems
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• 제8권4호
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• pp.589-602
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• 2012

With the increasing demand for real time applications in the Wireless Senor Network (WSN), real time critical events anticipate an efficient quality-of-service (QoS) based routing for data delivery from the network infrastructure. Designing such QoS based routing protocol to meet the reliability and delay guarantee of critical events while preserving the energy efficiency is a challenging task. Considerable research has been focused on developing robust energy efficient QoS based routing protocols. In this paper, we present the state of the research by summarizing the work on QoS based routing protocols that has already been published and by highlighting the QoS issues that are being addressed. The performance comparison of QoS based routing protocols such as SAR, MMSPEED, MCMP, MCBR, and EQSR has also been analyzed using ns-2 for various parameters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.248-250
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• 2004

We have investigated the surface state of 154kV polymeric insulators exposed to in-service conditions for about five years. In order to evaluate surface aging of silicone rubber exposed to real field environments, we used various analytic methods such as contact angle, ATR-FTIR, SEM-EDS. Although contaminants were accumulated on weathershed surface, polymeric insulator has retained its intrinsic surface hydrophocity. In addition, ATR-FTIR confirmed the diffusion layer of a low molecular weight silicone fluid on surface layer and no surface cracking and chalking were Indicated by SEM. Polymeric insulators have still retained their improved pollution performance over porcelain insulators. That will lead to very low frequency of flashovers throughout their useful life, often under contaminated conditions.

• Journal of Information Processing Systems
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• 제11권4호
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• pp.616-629
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• 2015

A mobile terminal will expect a number of handoffs within its call duration. In the event of a mobile call, when a mobile node moves from one cell to another, it should connect to another access point within its range. In case there is a lack of support of its own network, it must changeover to another base station. In the event of moving on to another network, quality of service parameters need to be considered. In our study we have used the Markov decision process approach for a seamless handoff as it gives the optimum results for selecting a network when compared to other multiple attribute decision making processes. We have used the network cost function for selecting the network for handoff and the connection reward function, which is based on the values of the quality of service parameters. We have also examined the constant bit rate and transmission control protocol packet delivery ratio. We used the policy iteration algorithm for determining the optimal policy. Our enhanced handoff algorithm outperforms other previous multiple attribute decision making methods.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제23권2호
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• pp.113-133
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• 2020

Pre-service teachers (PST) are students who are developing their mindset, persistence, instructional practices, and perception of tasks from two perspectives: as current students and as future teachers. As part of a larger study with PSTs engaged in a mindset intervention, this study quantitatively investigated PSTs mindset and persistence. During professional development (PD), PSTs engaged in multiple strategies (MS) tasks that promoted changes to PSTs mindset and persistence. PSTs' mindset pre- and post- PD were categorized after attending at least 4 interventions as fixed, mixed, or growth using the theory of intelligence, and their persistence as high or low using the Grit-S. Changes in categorization were noticed and explored for reasons of what could be done to make mindset interventions more effective such as consistently using challenging mathematics tasks with more open ended answers and focusing on discussion based mathematical lessons.

• Asia pacific journal of information systems
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• 제23권4호
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• pp.85-102
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• 2013

This study proposes a web presence readiness model based on pre-payment service functions and a post-payment service function both of which embrace the major concerns of customers in the online purchasing context. Based on the concept of customer utility from the product itself and instrumental utility, the research model suggests four antecedents including, Perceived Economic Benefits, Product Search Support Quality, e-Shopping Method Diversity, and Post-Payment Support Quality. We empirically examined a proposed research model using data collected from online rating company websites. Among the four antecedents, post payment support quality is found to be the most influential determinant of customer evaluation on e-commerce websites. Based on the empirical results, the current study proposes an alternate model of web presence readiness. The findings of this study may provide an insight to field practitioners designing commercial websites. The implications and future research directions are further discussed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.798-800
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• 2009

본 논문은 급증하는 항공 교통량을 처리하기 위해 국제민간항공기구(ICAO)를 중심으로 연구되고 있는 차세대 항공관제를 위한 시스템 중 비행자료처리시스템에서 효율적인 비행계획 상태 관리를 위한 방법론을 제안하고 있다. 본 논문에서 제안하는 비행계획 상태 관리는 입력되는 새로운 전문 및 관제사의 입력과 시간 타이머에 의한 이벤트를 구분하는 처리 구조이며, 두 가지를 병렬 처리하는 방식을 이용해서 정확하고 빠른 비행계획 상태 관리를 제공한다. 이는 향후 많은 항공 교통량을 처리하기 위한 차세대 항공관제 시스템에 적용되는 것을 그 목적으로 한다.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.203-206
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• 2021

The article is devoted to the study of the problems of polygraphic research to obtain forensically significant information. An analysis of the legal basis for the use of the polygraph in Ukraine. Problematic issues concerning the appropriateness of using a polygraph in the investigation and detection of crimes have been studied. The domestic legal norms that regulate this issue, as well as foreign experience are analyzed. The article reveals the essence of the polygraph, the legal basis and requirements for its use. Attention is drawn to the main difficulties of using a polygraph and ways to solve them.