• 토지주택연구
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• 제9권4호
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• pp.10-18
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• 2018

As the volatility increasement of the number of tourist, there was been controversy over supply-demand imbalance in hotel market. The purpose of this study is to analysis on determinants of hotel occupancy rate in Jeju Island. The quantitative method is based on cointegrating regression, using an empirical dataset with hotel from 2000 to 2017. The primary results of research is briefly summarized as follows; First, there are high relationship between total hotel occupancy rate and hotel occupancy of foreign tourist. The volatility of hotel occupancy is caused by foreigner user than local tourists though local tourist high propotion of hotel occupancy in Jeju Island. Second, hotel occupancy of local tourist has not relationship with demand and supply variables. Because some hotel users are not local tourists but local resident, and effects to other variables of hotel consumer trend, accommodation such as Guest house, Airbnb. Third, there are high relationship between foreign hotel occupancy rate and demand-supply variables. These research imply that total management of supply-demand is very important to seek stability of hotel occupancy rate in Jeju Island. Also it can provide a useful solution regarding mismatch problem between supply-demand as well as development the systematic forecasting model for hotel market participants.

• Journal of Communications and Networks
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• 제16권1호
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• pp.56-66
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• 2014

We propose a novel opportunistic access scheme for cognitive radios in an interweave cognitive system, that considers the channel gain as well as the predicted idle channel probability (primary user occupancy: Busy/idle). In contrast to previous work where a cognitive user vacates a channel only when that channel becomes busy, the proposed scheme requires the cognitive user to switch to the channel with the next highest idle probability if the current channel's gain is below a certain threshold. We derive the threshold values that maximize the long term throughput for various primary user transition probabilities and cognitive user's relative movement.

• 한국정보전자통신기술학회논문지
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• 제12권1호
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• pp.58-71
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• 2019

본 논문은 군 전술 무선 통신망에서의 가용 주파수 채널 확보를 위한 인지 라디오 엔진 플랫폼 구조 및 인지 라디오 무선기기를 위한 가용 주파수 채널 추론기법을 제안하였다. 현재의 군 전술 통신망은 동종 및 이종 군 무선기기 주파수의 효과적 운용을 위한 가용 주파수 확보 및 군 무선기기 간의 상호공존 방안에 대한 필요성이 빠르게 증가하고 있는 실정이다. 본 논문은 최적의 가용 주파수 채널확보 방안으로 동적 스펙트럼 접속(DSA, Dynamic Spectrum Access) 실현을 위한 인지 라디오 엔진 기술 기반의 가용채널 추론기법에 대해 소개하였다. 이를 위해 주사용자(PU, Primary User)의 채널 이용현황 모델링 및 채널 점유확률 계산을 통하여 인지 라디오 무선기기를 위한 사례 기반의 가용채널 추론기법을 제안하였으며, 성능분석 모의실험을 통하여 주사용자의 점유채널 정보 대비 인지 라디오 무전기의 가용채널 획득 정보 간의 충돌확률 변화율을 분석하였다.

• 교육시설
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• 제10권2호
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• pp.15-22
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• 2003

The purpose of this study is to find problems and to provide architectural design standards of the Learning Space Unit(L.S.U.) in Elementary Schools through the Post-occupancy Evaluation(POE). In this study, we found six major problems of the type of the L.S.U. in elementary schools. More than 50% of users expressed dissatisfactions in these items : size, safety, cooling facility, noise, privacy and primary meaning for its original purpose. After the interrelation-analysis, we checked pros and cons about each forms of L.S.U. It is the result of analysis of the layout method in L.S.U. 1) "$8.4m{\times}8.4m$" classroom unit got the highest positive responses 2) "2-classroom type" and "4-classroom type" got higher score than "3-classroom type" 3) "Whole faced type" 1) made more active Multi-space than "Partial faced type" 4) prefered prepared "Open-classroom" to "Closed-classroom" 5) 'Zoning type between L.S.U.s' couldn't influence to user's responses. Designers can consult those informations when they plan a new, remodeling and additional elementary school.

• ETRI Journal
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• 제34권5호
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• pp.771-774
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• 2012

Typical channel allocation algorithms for secondary users do not include processes to reduce the frequency of switching from one channel to another caused by random interruptions by primary users, which results in high packet drops and delays. In this letter, with the purpose of decreasing the number of switches made between channels, we propose a nonparametric channel allocation algorithm that uses robust kernel density estimation to effectively schedule idle channel resources. Experiment and simulation results demonstrate that the proposed algorithm outperforms both random and parametric channel allocation algorithms in terms of throughput and packet drops.

• Journal of Communications and Networks
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• 제16권2호
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• pp.217-226
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• 2014

In this research, we study the problem of opportunistic spectrum access (OSA) in a time-varying environment with fading channels, where the channel state is characterized by both channel quality and the occupancy of primary users (PUs). First, a finite-state Markov channel model is introduced to represent a fading channel. Second, by probing channel quality and exploring the activities of PUs jointly, a two-dimensional partially observable Markov decision process framework is proposed for OSA. In addition, a greedy strategy is designed, where a secondary user selects a channel that has the best-expected data transmission rate to maximize the instantaneous reward in the current slot. Compared with the optimal strategy that considers future reward, the greedy strategy brings low complexity and relatively ideal performance. Meanwhile, the spectrum sensing error that causes the collision between a PU and a secondary user (SU) is also discussed. Furthermore, we analyze the multiuser situation in which the proposed single-user strategy is adopted by every SU compared with the previous one. By observing the simulation results, the proposed strategy attains a larger throughput than the previous works under various parameter configurations.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1146-1153
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• 2022

As the population is aging, accidents involving elderly people are also increasing (2014:11,667 persons; 2018: 11,797 persons). In the case of the elderly population, falling accidents are the primary direct or indirect causes of death; in particular, they face an elevated risk of staircase falls. This study proposes a method of evaluating the safety of staircases using Building Information Modeling (BIM)-based virtual simulation. By making a virtual user with the behavioral characteristics of the elderly respond to a staircase in a BIM model, its safety performance can be evaluated. The evaluation criteria were derived from regulations, elements, and characteristics relevant to the safety of staircases. To validate the proposed method, safety evaluation tests were simulated on actual staircases. The evaluation result of the test simulation shows the safety scores of 1.97 points for the elderly user and 2.95 points for the average male adult user against a required safety score of a minimum of 2 points. That is, safety is relative to users as the safety of the same staircase can be different depending upon the different behavioral characteristics of users. The study suggests that the risk of staircase-related fall accidents to the elderly can be reduced by improving staircase designs through the proposed method.

• 한국실내디자인학회논문집
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• 제33호
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• pp.90-98
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• 2002

The purpose of this study is total analysis which is satisfied factors to users to object of inservice training institute in large enterprise. Common factors are inservice training building, outer space and unit of abode. Those are deduced in the planing stage by important degree. Methods of statistical analysis are enforced by analysis of primary factor, correlation and multiple regression. The result of this shows a difference between important orders to users according to character of influenced factors of the inservice training building and abode.

• 한국비블리아학회지
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• 제20권1호
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• pp.165-179
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• 2009

초등학교 학교도서관은 기본적으로 교육 및 정보를 전달하는 장소이기 때문에 교사와 학생의 이용 편의성을 높이고 교사의 업무를 효과적으로 지원 할 수 있도록 구성되어야 한다. 일반적으로 공간 구성은 세부 공간 간의 기능을 잘 연결할 수 있도록 공간과 가구의 경제적 배치(LAYOUT)가 주된 목적이다. 따라서 공간과 가구를 잘 배치하여 이용자가 편리하고 교육효과를 높이기 위해서는 초등학교 학교도서관의 기능공간의 배치유형을 조사 분석하는데 본 연구의 목적이 있다. 이와 같은 측면에서 학교도서관의 전문화, 다원화, 개성화 하여야하는 목적과 교육환경 및 사회변화에 능동적으로 대처하고자 초등학교 도서관의 사용자인 학생 측면에서 현황을 파악하고 공간의 점유 특성을 분석하였으며 초등학교 도서관 계획시 보다 효율적인 공간계획이 이루어지도록 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권5호
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• pp.1532-1553
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• 2014

Radio spectrum is a precious resource and characterized by fixed allocation policy. However, a large portion of the allocated radio spectrum is underutilized. Conversely, the rapid development of ubiquitous wireless technologies increases the demand for radio spectrum. Cognitive Radio (CR) methodologies have been introduced as a promising approach in detecting the white spaces, allowing the unlicensed users to use the licensed spectrum thus realizing Dynamic Spectrum Access (DSA) in an effective manner. This paper proposes a generalized framework for DSA between the licensed (primary) and unlicensed (secondary) users based on Continuous Time Markov Chain (CTMC) model. We present a spectrum access scheme in the presence of sensing errors based on CTMC which aims to attain optimum spectrum access probabilities for the secondary users. The primary user occupancy is identified by spectrum sensing algorithms and the sensing errors are captured in the form of false alarm and mis-detection. Simulation results show the effectiveness of the proposed spectrum access scheme in terms of the throughput attained by the secondary users, throughput optimization using optimum access probabilities, probability of interference with increasing number of secondary users. The efficacy of the algorithm is analyzed for both imperfect spectrum sensing and perfect spectrum sensing.