• Journal of Information Processing Systems
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• 제8권4호
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• pp.739-748
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• 2012

We propose an analytic model to compute the station's saturated throughput and packet delay performance of the IEEE 802.11 DCF (Distributed Coordination Function) in which frame transmission error rates in the channel are different from each other. Our analytic model shows that a station experiencing worse frame error rates than the others suffers severe performance degradation below its deserved throughput and delay performance. 802.11 DCF adopts an exponential back-off scheme. When some stations suffer from high frame error rates, their back-off stages should be increased so that others get the benefit from the smaller collision probabilities. This impact is then recursively applied to degrade the performance of the victim stations. In particular, we show that the performance is considerably degraded even if the frame error rate of the victim station satisfies the receiver input level sensitivity that has been specified in the IEEE 802.11 standard. We also verify the analytic results by the OPNET simulations.

• KIEAE Journal
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• 제8권5호
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• pp.43-48
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• 2008

This study is about offering quantitatively analytic frame of streetscape, and also about making a way to be standardized and adapt changing landscape. This allows us to manage a form of elevation map after the application to GIS. The form of elevation map is a visible and vertical arrangement method of data recognizable while walking or driving. Applying measurable traits enables us to make a quantitative control over each element of which streetscape consists. After all, it would play a great roll in organizing and maintaining fine streetscape of each city. As the basic ways to make the elevation map, this study proposes the methods of providing quantitative analytic frame of streetscape after applying elevation data, Raster Data and Vector Data, which were investigated on the basis of GIS. In addition, as a simulation for increasing reality, certain streets, where the streetscape is very important, were chosen so that they enable us to utilize quantitatively analytic data of streetscape with analyzing the +degree of opening ratio in the boundary of D/H=2, comparing between wall area and windowpane area, comparing between facade area and sign board area, and calculating both area and ratio which are applied to ecospace.

• 전자공학회논문지A
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• 제32A권1호
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• pp.26-35
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• 1995

Bo-Back-N ARQ is widely used in packet networks for error and flow control methanisms. This paper analyzes the network throughput under the go-back-N schem. Contrast to other analytic methods which assume independent frame losses or the first order Markov frame analytic methods which assume independent frame losses or the first order Markov frame losses concoptually, the proposed method takes into account the correlation between successive frame losses in a congested node. Computer simulation shows that our method generates more accurate performance results that independent assumption method. We apply the proposed method to analyze the performance of BWM in high speed networs. Our results show that BWM maintains the independence between traffic streams.

• 디지털융복합연구
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• 제12권12호
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• pp.181-188
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• 2014

본 연구는 제품의 가격에 부과가 되어 있는 부가가치세(Value Added Tax)를 어떻게 표시(VAT 프레임: VAT포함, VAT별도)하느냐에 따라 소비자들의 가격제시방법에 대한 태도가 달라질 수 있음을 살펴보았다. 또한 사고방식(종합적 vs. 분석적)에 따른 태도변화 즉, 조절효과도 살펴보았다. 이를 위해 실험자극물을 4가지 형태[(제품: 실용/쾌락)${\times}$(VAT: 포함/별도)]로 조작하였다. 1) 조사대상자들은 VAT별도 가격제시 방법보다 VAT포함 가격제시 방법을 더 선호하는 것으로 나타났다. 2) 사고방식의 조절효과도 확인되었다. 즉 분석적 사고자의 경우에는 전자와 후자 간에 유의미한 차이가 없는 것으로 나타났으며, 종합적 사고자의 경우에는 전자보다 후자를 더 선호하는 것으로 나타났다. 기업의 마케팅 실무 담당자들은 이와 같은 연구결과를 고려하여 효과적인 마케팅 전략을 수립하는데 도움을 받을 수 있을 것으로 기대된다.

• 한국자동차공학회논문집
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• 제23권3호
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• pp.336-343
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• 2015

One of various main jobs in the design of a new tactical vehicle is to develop the lightest chassis parts satisfying the required durability target. In this study, the analytic methods to reduce the size and weight of a lower control arm and chassis frame of a Korean light tactical vehicle are presented. Topology optimization by ATOM (Abaqus Topology Optimization Module) is applied to find the optimal design of the suspension arm with volume and displacement constraints satisfied. In case of chassis frame, the light-weight optimization process associated with design sensitivity method is developed using Isight and ABAQUS. By these analytic methods we can provide design engineers with guides to where and how much the design changes should be made.

• 한국웰니스학회지
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• 제7권2호
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• pp.25-37
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• 2012

The purpose of this study was to analyze the mass media's news framing on the elderly leisure. For this, researchers collected news articles from daily newspapers such as Chosun Ilbo, Hankyoreh, Kyunghyang Shinmun, and analysed the news framing of them through text-analytic approach. Total of 153 news the about elderly leisure between 1990 and 2010 were used for frame analysis. The Frame analyses were divided by formal frame and content frame. The formal frame was formed by deduction based on the classification method of Iyergar(1991) and the content frame was formed by induction according to the analysis of overall themes and titles of news. The main result could be summarized as follows: First, the analysis of formal frame showed that the episodic frame was predominantly high which focused on specific event or occurrences about elderly leisure. Second, it was found by content frame analysis that elderly leisure's facilities, health, serious leisure, policy frame were main subjects of news framing.

• 한국지구과학회지
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• 제29권7호
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• pp.586-601
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• 2008

본 연구의 목적은 과학자의 가설-연역적 탐구과정에서 가설설정단계, 실험설계단계, 결과해석단계에서 귀추적 추론이 나타나는지를 확인하고, 각각의 단계에서의 귀추적 추론과정을 분석하기 위한 분석틀을 제안하는 데 목적이 있다. 이를 위해, 8명의 과학자들과의 심층면담을 통해 얻은 프로토콜을, 기존 문헌에서 추출한 귀추적 추론과정의 하위요소로 분석해 보았다. 그 결과, 과학자의 귀추적 추론이 세 단계 모두에서 나타나고 있어 기존요소에 의한 분석틀을 벗어난 새로운 분석틀이 요구되었다. 그 결과 과학자들과의 심층면담을 통해 탐구의 각 단계에서 나타나는 귀추적 추론 분석틀을 새롭게 개발하였다. 이 틀을 과학교육전문가로부터 타당성 확인 결과, 내용타당도 지수 0.90을 얻어 타당한 것으로 인정되었으며, 실제로 과학자의 탐구과정에서 나타나는 귀추적 추론과정을 분석한 결과 매우 적절한 것으로 확인되었다.

• 한국통신학회논문지
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• 제24권9B호
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• pp.1624-1630
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• 1999

CDMA 이동 통신 시스템에서는 호를 진행중인 단말기가 인접한 기지국의 서비스 영역으로 이동할 때 호의 계속적인 서비스를 위하여 단말기가 handoff 영역에 있는 동안 인접한 기지국으로부터 동시에 서비스를 받는 soft handoff 방식을 사용한다. 이 때 soft handoff가 성공적으로 이루어지기 위해서는 진행중인 호가 이전의 기지국에서 서비스를 받을 때 사용되던 것과 동일한 frequency assignment와 frame offset을 새로운 기지국으로부터 할당받아야 한다. 새로운 호에 대해 frame offset을 할당할 때 인접한 기지국의 frame offset의 할당 상태를 고려하지 않고 해당되는 기지국의 frame offset의 할당 상태만을 고려할 경우 호가 인접한 기지국으로 soft handoff를 요청할 때 frame offset의 불일치로 인하여 soft handoff가 실패할 확률이 커질 수 있다. 본 논문에서는 이러한 문제점을 개선하기 위하여 인접한 기지국의 frame offset의 할당 상태를 고려하는 새로운 frame offset 할당 방법을 제안하고자 한다. 분석적인 방법을 통하여 새로이 제안된 frame offset assignment algorithm의 성능을 분석한 결과에 의하면 제안된 방법으로 handoff 영역에서 \ulcorner생한 호에 대해 frame offset을 할당할 경우 frame offset의 불일치로 인한 soft handoff blocking probability가 크게 작아지는 것으로 분석되었다.

• 한국경영과학회지
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• 제22권3호
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• pp.113-143
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• 1997

Most of the conflict problems between 2 persons can be represented as a bi-matrix game, because player's utilities, in general, are non-zero sum and change according to the progress of game. In the bi-matrix game the equilibrium point set which satisfies the Pareto optimality can be a good bargaining or coordination solution. Under the condition of incomplete information about the risk attitudes of the players, the bargaining or coordination solution depends on additional elements, namely, the players' methods of making inferences when they reach a node in the extensive form of the game that is off the equilibrium path. So the investigation about the players' inference type and its effects on the solution is essential. In addition to that, the effect of an individual's aversion to risk on various solutions in conflict problems, as expressed in his (her) utility function, must be considered. Those kinds of incomplete information make decision maker Bayesian, since it is often impossible to get correct information for building a decision making model. In Baysian point of view, this paper represents an analytic frame for guessing and learning opponent's attitude to risk for getting better reward. As an example for that analytic frame. 2 persons'bi-matrix game is considered. This example explains that a bi-matrix game can be transformed into a kind of matrix game through the players' implicitly cooperative attitude and the need of arbitration.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.1929-1945
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• 2011

RFID technologies have attracted a lot of attention in recent years because of their cost/time-effectiveness in large-scale logistics, supply chain management (SCM) and other various potential applications. One of the most important issues of the RFID-based systems is how quickly tags can be identified. Tag collision arbitration plays a more critical role in determining the system performance especially for passive tag-based ones where tag collisions are dealt with rather than prevented. We present a novel tag collision arbitration protocol called Optimum Frame-Slotted Aloha (OFSA). The protocol has been designed to achieve time-optimal efficiency in tag identification through an analytic study of tag identification delay and tag number estimation. Results from our analysis and extensive simulations demonstrate that OFSA outperforms other collision arbitration protocols. Also, unlike most prior anti-collision protocols, it does not require any modification to the current standards and architectures facilitating the rollout of RFID systems.