• 대기
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• 제28권3호
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• pp.247-261
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• 2018

The objective of this paper is to compare probabilistic temperature forecasts from different regional and global ensemble prediction systems over PyeongChang area. A statistical post-processing method is used to take into account combination and calibration of forecasts from different numerical prediction systems, laying greater weight on ensemble model that exhibits the best performance. Observations for temperature were obtained from the 30 stations in PyeongChang and three different ensemble forecasts derived from the European Centre for Medium-Range Weather Forecasts, Ensemble Prediction System for Global and Limited Area Ensemble Prediction System that were obtained between 1 May 2014 and 18 March 2017. Prior to applying to the post-processing methods, reliability analysis was conducted to identify the statistical consistency of ensemble forecasts and corresponding observations. Then, ensemble model output statistics and bias-corrected methods were applied to each raw ensemble model and then proposed weighted combination of ensembles. The results showed that the proposed methods provide improved performances than raw ensemble mean. In particular, multi-model forecast based on ensemble model output statistics was superior to the bias-corrected forecast in terms of deterministic prediction.

• ETRI Journal
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• 제33권3호
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• pp.382-392
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• 2011

This paper proposes the streaming radio frequency identification (RFID) protocol to support robust data streaming in a passive communication, which is extended from the ISO18000-6 Type C RFID standard. By observing and modeling the unique bit error behavior through detailed analysis in this paper, we found that performance is significantly limited by inaccurate and unstable link frequencies as well as low SNR which are inevitable for passive devices. Based on the analysis, we propose a simple and efficient protocol to adaptively insert extra error control sequences in a packet for tolerating tough link condition while maximizing the throughput and preserving the minimal implementation cost. To evaluate effectiveness of our proposal in real-time streaming applications, we experimented on real-time H.264 video streaming and prototyped the system on FPGA. To our best knowledge, our paper is the first work to take analytical approach for maximizing the throughput and demonstrate the possibility of the realtime multimedia streaming transmission in the passive RFID system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1936-1939
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• 2002

Much recent attention on wireless technologies s put on topology-less wireless network, in which all nodes an be mobile and can communicate over wireless links, due to its ease of deployment, high flexibility and low expenses. One key in topology-less wireless network is mobile base stations (MBSs), which provides access points or mobile terminals (MTs) to wireless backbone network. MBSs can move to anywhere in accordance with changes in geographical distribution of MTs. They serve as dynamic odes. However, in order to utilize network resources and take full advantage of this topology-less network, MBSs must move to suitable position according to the current tate of network use. Moreover, MBSs have to consider the distance among them to avoid the crash and gap area of MBSs. Therefore, this paper proposes MBS movement algorithm by implementing push-pull method to fulfill the corporation of MBSs and considering the center of covered MTs or centroid to satisfy the MT coverage. From the simulation results, the proposed algorithm increases the performance of system when comparing with the centroid-based algoriom〔7〕, such as coverage area, MT coverage and call drops rate.

• 한국인터넷방송통신학회논문지
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• 제11권1호
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• pp.67-73
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• 2011

최근 스마트 폰 기술의 급속한 발전에 힘입어 모바일 컴퓨팅 환경에서의 온라인 게임의 설계에 대한 관심이 높아지고 있다. 그러나 모바일 단말인 스마트 폰은 비교적 낮은 성능의 프로세서, 저해상도의 GUI, 작은 메모리 공간과 짧은 배터리 파워 등의 제한으로 온라인 게임 구현에 많은 제약이 따른다. 따라서 대부분의 게임은 온라인이나 멀티 플레이 기능이 매우 제한적이다. 본 논문에서는 이러한 모바일 환경의 제약을 극복할 수 있는 컴포넌트 기반 스마트 폰 환경에서의 효율적인 모바일 온라인 게임 앱을 설계하고 구현하였다. 특히 본 논문에서 구현한 모바일 게임은 Wi-Fi를 기반으로 게임 서버와 다른 스마트 폰 간의 온라인 게임이 가능하도록 구현하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.91-97
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• 2006

Currently, approx. 10,532 turnouts were installed on the KR line, of which 3,644 turnouts were installed in the main line where high speed operation is performed. This shows that it is necessary to improve the performance of turnout as one of vulnerable areas for the safe operation of a train. Even though the number of railway accidents is decreasing every year due to the renewal of railway facilities, there are still many factors that cause the occurrence of an accident. In particular, an incident in turnout area does not only have a high risk of a serious accident but also affect the operation of a train on the adjacent track in most cases, and consequently a big social loss is expected due to the delay in train operation as well as the loss of life and property. The objective of this study is to examine the accidents occurred in turnout area that is one of typical　vulnerable areas over the past ten years, on the basis of the results, and to take an appropriate measure by finding out the major cause of accidents in turnout area so that a systematic safety system can be established to prevent or reduce accidents in turnout area.

• 한국염색가공학회지
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• 제34권3호
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• pp.197-206
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• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.

• 융합경영연구
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• 제4권4호
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• pp.1-16
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• 2016

In today's knowledge-based economy, measurement and disclosure (M&D) of intellectual capital (IC) are crucial for enhancing business performance and competitiveness. In the global world, M&D of IC are useful means to keep investors well-informed and reduce information asymmetry. At present, very few leading corporations in India have disclosed IC information on a 'voluntary' basis. Traditional accounting practices, therefore, will need to assimilate innovations that seek to meaningfully represent the 'true-value' of the intangible assets of the company. This is an exploratory study of IC M&D by 8 Indian companies over 5-year period, using 'content' analysis and market-value-added (MVA) as research methodologies. The annual reports of companies were collected from their respective websites. As part of present study, various statistical techniques have been used to analyze the data. The findings show that the sample companies, on an average, reported a positive value of IC, along with wide-disparity, low-level of ICD. Unfortunately, the omission of IC information may adversely influence the quality of decisions made by shareholders, or lead to material misstatements. Finally, we recommend to "the international accounting bodies, to take the lead by establishing a harmonized ICD standard, and provide guidance to the big listed-companies for proper measurement and disclosure of IC, both for internal and external users."

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1209-1216
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• 2022

The majority of construction site incidents occur due to a lack of hazard awareness among workers on job sites. This lack of awareness is despite mandatory construction safety training, typically in the form of written content (safety manuals) or of images depicting hazards. To reduce job-site injuries and fatalities, general contractors have started adopting Virtual Reality (VR) to impart safety training to job site personnel. VR safety training can take the form of an immersive simulation comprising potential safety hazards intentionally embedded into a virtual job site; users are required to identify these hazards within a specified time frame with the expectation that they will be more adept at recognizing hazards on an actual job-site, resulting in fewer accidents. This research study seeks to identify the actual impacts of VR on construction safety awareness among participants. The research addresses the following question: Does VR improve hazard recognition awareness? The primary objective is to evaluate participants' performance of past construction safety awareness against present construction safety awareness after receiving VR training. Participants were asked to complete a multiple-choice Qualtrics™ questionnaire. The results of the study showed a statistically significant knowledge gain advantage with respect to hazard recognition and construction safety awareness with the use of interactive, immersive VR over a more conventional and passive safety training method.

• 전자통신동향분석
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• 제38권6호
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• pp.31-40
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• 2023

Given recent accidents involving autonomous vehicles, driver monitoring technology related to the transition of control in autonomous vehicles is gaining prominence. Driver status monitoring systems recognize the driver's level of alertness and identify possible impairments in the driving ability owing to conditions including drowsiness and distraction. In autonomous vehicles, predictive factors for the transition to manual driving should also be included. During traditional human driving, monitoring the driver's status is relatively straightforward owing to the consistency of crucial cues, such as the driver's location, head orientation, gaze direction, and hand placement. However, monitoring becomes more challenging during autonomous driving because of the absence of direct manual control and the driver's engagement in other activities, which may obscure the accurate assessment of the driver's readiness to intervene. Hence, safety-ensuring technology must be balanced with user experience in autonomous driving. We explore relevant global and domestic regulations, the new car assessment program, and related standards to extract requirements for driver status monitoring. This kind of monitoring can both enhance the autonomous driving performance and contribute to the overall safety of autonomous vehicles on the road.

• 융합보안논문지
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• 제16권6_1호
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• pp.15-24
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• 2016

인천상륙작전은 1950년 9월 15일에 연합군과 한국 해병대가 실시한 한반도 최초의 연합상륙작전이었다. 인천상륙작전의 역사적 의의는 낙동강방어전선에서 반격을 위한 공세이전으로 전환시켜 수도 서울 탈환이라는 계기를 마련하였다는 점에 있다. 인천상륙작전간 한국해병대는 미군들의 주요지휘관들로부터 "한국 해병대의 철저한 전투수행에는 어떠한 결함도 발견할 수 없었다"고 격찬을 받으면서 위국헌신의 희생정신으로 한국해병대의 위용을 전 세계에 과시하였다. 오늘날 우리 해병대가 국민들에게 사랑과 신뢰를 받으면서 국민의 군대로서 성장할 수 있었던 것은 평시 강한 훈련을 통하여 유사시를 대비했기 때문이었다. 앞으로도 장병들의 주적개념과 국가관을 확립토록 정신교육을 강화하고 또한 강한 훈련을 통하여 싸우면 반드시 이긴다라는 자신감을 배양토록 힘써야 할 것이다. 특히 구타 및 가혹행위 등의 잘못된 전통을 척결하여야 할 것이다. 선배해병들의 피와 땀과 눈물어린 전통을 보다 계승 발전시켜 국민에게 신뢰받는 해병대가 되도록 최선을 다해야 할 것이다.