• ETRI Journal
• /
• 제38권4호
• /
• pp.622-633
• /
• 2016

A discontinuous reception (DRX) operation is included in the Long Term Evolution (LTE) system to achieve power saving and prolonged battery life of the user equipment. An improvement in DRX power saving usually leads to a potential increase in the packet delay. An optimum DRX configuration depends on the current traffic, which is not easy to estimate accurately, particularly for non-real-time applications. In this paper, we propose a novel way to vary the DRX cycle length, avoiding a continuous estimation of the data traffic when only non-real-time applications are running with no active real-time applications. Because a small delay in non-real-time traffic does not essentially impact the user's experience adversely, we deliberately allow a limited amount of delay in our proposal to attain a significant improvement in power saving. Our proposal also improves the delay in service resumption after a long period of inactivity. We use a stochastic analysis assuming an M/G/1 queue to validate this improvement.

• KIEAE Journal
• /
• 제3권2호
• /
• pp.33-36
• /
• 2003

The influence of the visual information on the sound perception would be considerable. Furthermore, if the sound perception ranges in noisiness or annoyance beyond the loudness, it will depend much more on the shape of the visual information. This paper aims to estimate the influence of the several kinds of visual information on the perception of road traffic noise by means of the psycho-acoustic test method. The findings of present study on the influence of visual information on subjective noise perception are summarized as follows: Presenting visual images of mild and comfortable scenery reduced the noise perception reaction at the less noisy environments not exceeding 65 dB(A). At highly noisy environments exceeding 65 dB(A), however, the noise perception can be reduced by strong image of waterfall. Even eliminating the road traffic image may be helpful. Visual image of waterfall reduced the noise perception at all levels. It is inferred that the road traffic noise perception can be effectively ameliorated by presenting strong and real landscape images at any noisy environment.

• 한국도로학회논문집
• /
• 제14권5호
• /
• pp.11-19
• /
• 2012

PURPOSES: The new methodology is proposed for estimation of long-term performance and pavement life based on the national highway database in Daejeon area. Furthermore, this study tried to verify the applicability of performance estimation using NHPCI (National Highway Pavement Condition Index) on tendency of pavement deterioration as time goes by under Korean road environments. METHODS: Reliability theories are applied to estimate the mean life and to determine the appropriate distribution using 3 levels of traffic loads (high, medium, low) based on maintenance and rehabilitation history data for 15 years. RESULTS: As a result, Lognormal distribution is suitable for explanation of pavement lifetime in Daejeon area regardless of traffic loads. In addition, we found that the results of mean life and maintenance timing based on NHPCI for the pavement sections of 3 levels of traffic loads are available. CONCLUSIONS: Based on this study, it was found that mean life of high, medium and low levels of traffic loads are about 8.1 years, 12.2 years and 12.7 years, respectively. Higher level of traffic loads shorten the pavement mean life.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권8호
• /
• pp.3804-3819
• /
• 2018

The increasing popularity of HTTP adaptive video streaming services has dramatically increased bandwidth requirements on operator networks, which attempt to shape their traffic through Deep Packet inspection (DPI). However, Google and certain content providers have started to encrypt their video services. As a result, operators often encounter difficulties in shaping their encrypted video traffic via DPI. This highlights the need for new traffic classification methods for encrypted HTTP adaptive video streaming to enable smart traffic shaping. These new methods will have to effectively estimate the quality representation layer and playout buffer. We present a new machine learning method and show for the first time that video quality representation classification for (YouTube) encrypted HTTP adaptive streaming is possible. The crawler codes and the datasets are provided in [43,44,51]. An extensive empirical evaluation shows that our method is able to independently classify every video segment into one of the quality representation layers with 97% accuracy if the browser is Safari with a Flash Player and 77% accuracy if the browser is Chrome, Explorer, Firefox or Safari with an HTML5 player.

• 한국산학기술학회논문지
• /
• 제7권6호
• /
• pp.1142-1148
• /
• 2006

실제적으로, 현재의 교통사고 검지시스템은 주로 교차로에서의 영상정보와 디지털 영상처리기술에만 거의 의존하고 있기 때문에 교차로에서의 혼잡한 상황하에서는 정확한 판별의 제한이 잔존하고 있다. 이러한 문제점을 보완하기 위하여, 본 논문은 교차로에서의 교통사고 자동검지율의 향상을 위해 검토되어야 할 사고음의 음향특성을 분석함으로써 현재 기술수준과 실현가능성을 가늠해 보는 것을 목적으로 한다. 교차로 주변에 차량의 소통이 거의 없을 때는 자동차사고 스키드음은 1[KHz]$\sim$3[KHz] 대역에서 특정패턴을 보였다. 또한, 차량 충돌음의 주파수 대역은 500[Hz]이하에서 사고가 발생하지 않은 시점보다 높은 30[dB] 이상의 음압차이를 보였다.

• 대한교통학회지
• /
• 제13권1호
• /
• pp.167-183
• /
• 1995

The objective of study is to evaluate highway capaicty estimation alternative and to develop capacity from statistical distribution of observed traffic flow. Speed-Volume relation is analyzed from vehicle's headway distribution eliminating the long headway by confidence intervals 99%, 95%, 90%. Capacity estimate alternatives were evaluated from 95% , 90%, 85% level of cummulative distribution of observed hourly traffic flow adjusted to confidence intervals. The result of investigation revealed that maximum hourly rate of flow is 2, 130pcu at confidence interval of 995, 2, 233pcu at 95%, 2, 315pcu at 90% respectively. Compared to the capacity of 2, 200pcu per hour per lane used in HCM and KHCM(Korea Highway Capacity Manual), capa챠y appears to correspond to confidence interval of 95%. Using the traffic flow rate at confidence interval of 95% the maximum hourly flow rate is 2, 187pcu at 95% of cummulative volume distribution, 2, 153pcu at 90%, 2, 215pcu at 85%. The study suggests that raional capacity esimation alternative is to take the 95% of cummulative distribution of observed hourly traffic flow at 95% confidence headway interval eliminating 5% long headway.(i.e. 95-95 rule)

• 산업기술연구
• /
• 제39권1호
• /
• pp.27-31
• /
• 2019

Semiconductor logistics systems are facing difficulties in increasing production as production processes become more complicated due to the upgrading of fine processes. Therefore, the purpose of the research is to design predictive models that can predict traffic during the pre-planning stage, identify the risk zones that occur during the production process, and prevent them in advance. As a solution, we build FABs using automode simulation to collect data. Then, the traffic prediction model of the areas of interest is constructed using deep learning techniques (keras - multistory conceptron structure). The design of the predictive model gave an estimate of the traffic in the area of interest with an accuracy of about 87%. The expected effect can be used as an indicator for making decisions by proactively identifying congestion risk areas during the Fab Design or Factory Expansion Planning stage, as the maximum traffic per section is predicted.

• 한국위험물학회지
• /
• 제6권2호
• /
• pp.68-76
• /
• 2018

This study aims to provide a methodological framework to estimate the travel demand of hazardous materials transporting vehicles by link and analyze daily traffic patterns on an expressway to develop safety roadway management strategies. Traffic volume of hazardous material vehicles is counted through the on-site investigation at twenty-five tollgates on the expressway, and their demands by a link are predicted through origin-destination flows estimation. The result shows that the number of the domestic hazardous materials vehicles is approximately 51,207 vehicles per day and it indicates that hazardous materials transport vehicles account for 1.5% of total daily traffic on the internal expressway and 6.2% of total cargo traffic volumes. This study roughly estimated how many hazardous materials vehicles pass through the expressway segment. Thus it is expected to be utilized for establishing a systematic highway management strategy in the future by calculating the traffic volume of the hazardous material vehicles traveling on the interstate expressway.

• 한국항해항만학회지
• /
• 제38권1호
• /
• pp.65-71
• /
• 2014

국내 경부고속도로와 남해고속도로는 부산항을 각각 남북방향과 동서방향으로 연계하며 20%이상의 중대형화물트럭 혼재율과 특정시간대 통행량이 집중되는 핵심 간선도로로 시간교통량계수(K-factor)에 대해 연구의 필요성을 깨닫게 되었다. 그리하여 본 연구에서는 경부고속도로와 남해고속도로의 기본구간에서 단기간동안 수집된 차량검지시스템(vehicle detection system, VDS)자료를 이용하여 고속도로의 K-factor와 K-factor추정치(estimate)사이의 상관분석을 통해서 고속도로의 K-factor추정모형 구축을 목적으로 연구하였다. 결과적으로 7일 VDS자료의 K-factor추정치(estimate)와 함께 파워(POW)모형이 K-factor를 추정에 높은 설명력과 신뢰성이 있음을 확인할 수 있었다.

• 대한토목학회논문집
• /
• 제33권5호
• /
• pp.1969-1980
• /
• 2013

우리나라 인구 10만 이상 대다수의 도시는 교통수요 증가로 인해 교통 혼잡이 발생하고 있으며 이로 인한 경제적 손실은 매년 증가하고 있다. 교통 혼잡으로 인한 경제적 손실을 감소시킬 수 있는 방법 중 개인차량의 운행 억제를 위해 카 쉐어링, 렌터카 등의 시스템이 첨단 IT 기술들과 접목되어 등장하고 있다. 이러한 차량 공유는 교통 혼잡을 완화하고 차량의 효율성을 증대시켜 차량유지비 절약, 자동차를 소유하려는 인간의 욕구 감소, 차량소유의 번거로움 완화, 비즈니스 및 개인용무 활용, 대중교통 수단과의 연계성을 향상시키며, 저탄소, 친환경 교통의 구현을 목적으로 하고 있다. 본 논문에서는 차량공유시스템에 대한 개념, 국내외 차량공유 시스템, 각종 교통 시스템의 요금 체계를 고찰하였다. 아울러 자동차 공유기반의 서비스 중 하나인 클라우드 교통 시스템에서 가장 중요한 요소인 최적의 이용 요금에 대해 추정하였다. 이를 위해 유사교통 수단 요금 체계 분석을 통해 운영원가와 이용원가가 포함된 요금을 산정하는 방법론을 제시하였다. 유사교통수단과의 요금 비교분석을 통해 최대, 최소요금 범위를 설정하였으며, 가치기준결정법을 이용해 실제 이용할 수요와 지불의사금액을 추정하였다. 시간당 최소요금은 렌터카 요금과 비교하여 5,333원으로 추정되었으며, 최대요금은 택시요금과 비교하여 17,700원, 이용자의 시간당 지불의사금액은 6,930원으로 추정되었으며, 50%수요시의 가격은 시간당 6,550원으로 추정되었다. 향후연구로 이용자들의 이용시간, 날씨, 수요패턴, 추세 등을 보다 세밀히 분석하여 이를 요금 산정에 반영하는 연구되어야 할 것이다.