• 한국정보과학회논문지:정보통신
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• 제37권6호
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• pp.483-488
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• 2010

모바일 기기와 네트워크 기술의 발달로 다양한 멀티미디어 응용 서비스가 빠르게 발전 및 보급되고 있다. 그리고, 사용자의 참여형 방송 서비스가 가능하며 이를 이용한 실시간 뉴스 등 다양한 정보 전달의 수단으로 이용되고 있다. 이러한 라이브 멀티미디어 스트리밍 서비스 사용자의 체감 품질을 만족시키기 위해서는 영상품질 이외에도 재생연속성과 재생지연한계를 고려해야 한다. 본 논문에서는 모바일 기기에서 실시간 스트리밍시 비디오 재생연속성과 재생지연한계를 보장하는 DeBuG (Delay Bounds Guaranteed) 전송률 조절 기법을 제안하였다. 제안한 기법유 실시간 비디오처리 시스템의 특성을 고려하여 송신 버퍼의 상태와 네트워크 상태를 인지하여 서비스 연속성과 지연한계를 보장하는 품질 적응 기능을 가지고 있으며, 비디오 영상의 품질을 보장하며 전달의 지연한계를 보장하기 위해 미디어의 프레임을 선택적으로 폐기하는 기능을 가지고 있다. 제안한 DeBuG 전송률 조절 기법의 주요 성능은 시뮬레이션을 통하여 보였다.

• 디지털융복합연구
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• 제17권1호
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• pp.55-62
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• 2019

본 연구는 주택가격의 변화가 거시경제변수와 소득불평등에 영향을 미치는 중요한 요인으로 작용하였을 것으로 판단하여 주택 전세가격과 매매가격, 지니계수, 금리, 취업자수와의 관계를 분석하였다. 2003년부터 2016년까지 국내 16개 광역시 도의 자료를 활용한 패널분석을 하였고 패널자료임을 감안하여 패널 VAR모형을 구축한 뒤 그랜저인과관계, 충격반응함수, 분산분해분석을 실시하였다. 그랜저인과성 검사와 충격반응검사 결과, 주택시장의 매매가격과 취업자수, 금리가 소득불평등에 유의한 영향을 미치는 것으로 나타났다. 글로벌 금융위기 이전에는 전세가격만이 통계적으로 유의한 결과를 보였지만 금융위기 이후에는 주택 전세가격과 매매가격이 유의한 영향을 미치는 것으로 나타났다. 또한 분산분해분석 결과에서는 금융위기 이전에는 전세가격이 소득불평등에 미치는 영향력이 크게 나타난 반면에 금융위기 이후에는 전세가격의 영향력이 낮아지고 금리가 큰 영향을 미치는 것으로 나타나, 금리, 취업자수, 주택시장의 매매가격과 전세가격이 소득불평등에 주요한 요인으로 작용할 수 있다는 것으로 확인되었다. 따라서 정부의 부동산 정책을 비롯한 경제 활성화를 위한 정책시 변수들간의 영향력을 고려하여 소득불평등을 완화시킬 수 있는 정책수립이 될 수 있길 기대한다.

• Journal of Animal Science and Technology
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• 제60권5호
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• pp.14.1-14.12
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• 2018

Background: Sheep production is a major component of the livestock sector in Ethiopia. The country owing to the large population of 30.70 million estimated numbers of sheep in the country and out of which about 72.14% are females, and 27.86% are males with diverse genetic resources. The real value of indigenous breeds was often under-estimated mostly due to their poor appearance and relatively low productivity. Developing countries in most cases opt for exotic breeds to increase animal productivity through crossbreeding or breed substitution without properly investigating the production potential of the indigenous breeds. The main objective of the research was to identify sheep flock composition and structure, farmers' traits of interest and breeding objective of Wollo highland sheep, and their $F_1$ crossbreed progenies. Results: Smallholder farmers' flock synthesized from breeding ewes, breeding rams, pre-weaned ewe lambs, pre-weaned ram lambs, unproductive ewes, castrated and fattened rams, with the percentage coverage of 29.2, 13.3, 15.5, 16.5, 12.4, and 12.5%, respectively. The maximum number of flock size was 289.0 sheep per flock and higher in the third stratum. The off-take rate percentage of the three strata presented as 21.9% in 1st stratum, 12% in the 2nd stratum, and 16.4% in the 3rd stratum and higher off-take rate recorded in the first stratum. Sheep producer's traits of interest ranked by growth rate (first), body size (second) and marketing value was third rank. Communal breeding (random mating), village based controlled breeding, mixed type and private ram controlled breeding practice were comprised of 39.7, 61.7, 52 and 71.3%, respectively. The percentages of ewes per flock composition were presented as 36.5, 27.1 and 25.5%, respectively in the 3rd stratum, 2nd stratum and 3rd stratum in the order of their importance's. Conclusion: Genetic improvement practices at smallholder sheep producers situation was showing promising outcome with indigenous Washera $F_1$ crossbred lambs and which designated for weaning rate, body size, marketing age, age at first lambing, good temperament and large litter size in the order of their rank. The contemporary breeding practice tendency indicated that, reduced flock size to improve flock productivity via crossbreeding practices.

• 국제지역연구
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• 제14권1호
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• pp.3-29
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• 2010

본 논문의 목적은 해외에서 발생하는 화폐교란과 실물교란이 중간재를 수입하는 소국경제에 어떤 영향을 미치는지 알아보고, 또한 소국에서의 물가상승에 대한 명목임금연동정도가 해외경제교란이 소국경제에 전파되는 과정에 어떤 영향을 미치는지 알아보는데 있다. 이를 위해 본 논문에서는 변동환율제 하에서 자본이동이 완전하며, 합리적 기대가정 하에서 2국 2재화 모형을 채택하였다. 본 논문의 분석결과에 의하면 해외에서 발생하는 화폐교란과 실물교란은 가격효과, 해외승수효과, 자본이동을 통한 이자효과, 물가와 환율변동에 의한 상대가격효과, 그리고 실질잔고효과를 통하여 소국경제에 영향을 미치는 것으로 나타났다. 본 논문에서는 한국과 미국의 통계자료를 사용하여 실증분석을 하였다. 이를 통해 미국에서 발생하는 화폐교란과 실물교란이 한국경제에 어떤 영향을 미치는지, 그리고 한국에서의 임금연동지수가 미국에서 발생하는 경제교란이 한국경제에 전파되는 과정에 어떤 영향을 미치는지 알아보았다.

• 자동차안전학회지
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• 제14권2호
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• pp.57-69
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• 2022

Recently, as interest in self-driving cars has increased worldwide, research and development on the Advanced Driver Assist System is actively underway. Among them, the purpose of Adaptive Cruise Control (ACC) is to minimize the driver's driving fatigue through the control of the vehicle's longitudinal speed and relative distance. In this study, for the research of the ACC test in the real environment, the real-road test was conducted based on domestic-road test scenario proposed in preceding study, considering ISO 15622 test method. In this case, the distance measurement method using the dual camera was verified by comparing and analyzing the result of using the dual camera and the result of using the measurement equipment. As a result of the comparison, two results could be derived. First, the relative distance after stabilizing the ACC was compared. As a result of the comparison, it was found that the minimum error rate was 0.251% in the first test of scenario 8 and the maximum error rate was 4.202% in the third test of scenario 9. Second, the result of the same time was compared. As a result of the comparison, it was found that the minimum error rate was 0.000% in the second test of scenario 10 and the maximum error rate was 9.945% in the second test of scenario 1. However, the average error rate for all scenarios was within 3%. It was determined that the representative cause of the maximum error occurred in the dual camera installed in the test vehicle. There were problems such as shaking caused by road surface vibration and air resistance during driving, changes in ambient brightness, and the process of focusing the video. Accordingly, it was determined that the result of calculating the distance to the preceding vehicle in the image where the problem occurred was incorrect. In the development stage of ADAS such as ACC, it is judged that only dual cameras can reduce the cost burden according to the above derivation of test results.

• 대한임베디드공학회논문지
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• 제6권1호
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• pp.8-15
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• 2011

This paper presents an effective method for detecting vehicles in front of the camera-assisted car during nighttime driving. The proposed method detects vehicles based on detecting vehicle headlights and taillights using techniques of image segmentation and clustering. First, in order to effectively extract spotlight of interest, a pre-signal-processing process based on camera lens filter and labeling method is applied on road-scene images. Second, to spatial clustering vehicle of detecting lamps, a grouping process use light tracking method and locating vehicle lighting patterns. For simulation, we are implemented through Da-vinci 7437 DSP board with visible light mono-camera and tested it in urban and rural roads. Through the test, classification performances are above 89% of precision rate and 94% of recall rate evaluated on real-time environment.

• Communications for Statistical Applications and Methods
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• 제27권6호
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• pp.625-639
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• 2020

The gamma distribution is a flexible right-skewed distribution widely used in many areas, and it is of great interest to estimate the probability of a random variable exceeding a specified value in survival and reliability analysis. Therefore, the study develops a fixed-accuracy confidence interval for P(X > c) when X follows a gamma distribution, Γ(α, β), and c is a preassigned positive constant through: 1) a purely sequential procedure with known shape parameter α and unknown rate parameter β; and 2) a nonparametric purely sequential procedure with both shape and rate parameters unknown. Both procedures enjoy appealing asymptotic first-order efficiency and asymptotic consistency properties. Extensive simulations validate the theoretical findings. Three real-life data examples from health studies and steel manufacturing study are discussed to illustrate the practical applicability of both procedures.

• 한국전자통신학회논문지
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• 제12권3호
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• pp.499-506
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• 2017

현재 주택시장과 전세시장의 문제점을 도출하고 이를 해결하는 데 있어 자본시장 부분과 금리 부분 그리고 실물 시장으로 구분하여 많은 영향을 미치는 지표들을 감안하여 주택매매 시장과 주택 전세시장의 안정화를 위한 대책 마련에 중요한 지표가 될 것으로 보인다. 특히, 향후에 예측되는 경제위기 상황과 불확실한 미래의 또 다른 금융위기를 예측하여 부동산 가격의 급격한 변동에 사전 대비할 수 있는 자료를 공공데이터를 사용하여 제공코자 한다.

• 한국정보시스템학회지:정보시스템연구
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• 제22권3호
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• pp.43-58
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• 2013

This work investigates factors that may affect the choice of real options by ERP project managers. Financial theory suggest that these factors include risk-free interest rate, time to maturity, volatility of net present value, and options exercise price. Other than these factors, we are interested in the exogenous risks related to external uncertainties about technological cost, user learning and consulting, and so forth and we argue these risks should have a significant impact upon the volatility of net present value. To validate these factors empirically, we collected survey questionnaires from ERP project managers in Korea. We find that perceived exogenous risks with regard to ERP projects influence volatility and additionally find that ERP project managers prefer contract options of the project when the volatility of the project is expected to be high. We expect that this work will not only validate theoretical propositions but help project managers consider ERP options strategically based on these factors.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.171-182
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• 2015

The general wavelet transform has profitable property in non-stationary signal analysis specially. The tunable Q-factor wavelet transform is a fully-discrete wavelet transform for which the Q-factor Q and the asymptotic redundancy r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The transform is based on a real valued scaling factor and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its over-sampling rate, with modest over-sampling rates being sufficient for the analysis/synthesis functions to be well localized. This paper describes filter design of 2D discrete-time wavelet transform for which the Q-factor is easily specified. With the advantage of this transform, perfect reconstruction filter design and implementation for performance improvement are focused in this paper. Hence, the 2D transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. Therefore, application for performance improvement in multimedia communication field was evaluated.