• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.16-26
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• 2011

Variable speed limit(VSL) is one of the highway ITS techniques designed to prevent accidents and traffic slow down by reducing congestion or speed variation between vehicles and lanes prior to arrive at the accident location by limiting speed. In Korea, while people have recognized the need for variable speed limit beginning with Seoul's urban expressway and installed facilities in order to provide guide for speed limit per lane and lane use, there has not been enough development of algorithm for internal administration as well as research on the basic principles behind administering variable speed limit. This study is for modeling and evaluating the VSL strategies based on the traffic flow theory. Supply-Demand method of the Cell Transmission Model is applied to demonstrate the traffic features and shockwaves to upstream of the bottleneck with/without VSL. We verified the explanation of Cell Transmission Model for the numerical example. and as the result, it is found that VSL strategies can reduce the total travel time in the congested section and variation of the speed. It means VSL is useful to improve the traffic condition and the safety on highway

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.50-58
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• 2014

The PRT(Personal Rapid Transit) system is highly interested to meet a need for demand-responsive transport service and increasing demands of traffic in Korea recently. And it is being spotlighted as an eco-friendly transportation system. For these reasons, researches on the PRT system are actively undergoing in Korea. In this study, we evaluated the static structural and fatigue strengths based on ASCE-APM standards and ERRI B 12/RP 17 by means of FE simulation. We also evaluate the running stability by multi-body dynamic analyses and the rollover safety by a theoretical static stability factor according to the road modeling scenarios for the PRT system. From the results of this study, we confirmed the durability and running stability of the Korean PRT under development.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.849-857
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• 2011

Gaming on demand(GOD) makes people enjoy games by encoding and transmitting game screen at a server side, and decoding the video at a client side. In this paper, we propose a fast game video encoder for multiple users over network with low-powered devices. In the proposed system, the computational complexity of game encoders is reduced by using scene descriptors, which consists of an object motion vector, global motion, and scene change. With additional information from game engines, the proposed encoder does not need to perform various complexity processes such as motion estimation and ratedistortion optimization. The motion estimation and rate-distortion optimization skipped by scene descriptors. We found that the proposed method improved 192 % in terms of FPS, compared with x264 software. With partial assembly code, we also improved coding speed by 86 % in terms of FPS. We found that the proposed fast encoder could encode over 60 FPS for real-time GOD applications.

• International Journal of Contents
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• v.13 no.2
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• pp.29-34
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• 2017

Cloud computing is becoming an effective and efficient way of computing resources and computing service integration. Through centralized management of resources and services, cloud computing delivers hosted services over the internet, such that access to shared hardware, software, applications, information, and all resources is elastically provided to the consumer on-demand. The main enabling technology for cloud computing is virtualization. Virtualization software creates a temporarily simulated or extended version of computing and network resources. The objectives of virtualization are as follows: first, to fully utilize the shared resources by applying partitioning and time-sharing; second, to centralize resource management; third, to enhance cloud data center agility and provide the required scalability and elasticity for on-demand capabilities; fourth, to improve testing and running software diagnostics on different operating platforms; and fifth, to improve the portability of applications and workload migration capabilities. One of the key features of cloud computing is elasticity. It enables users to create and remove virtual computing resources dynamically according to the changing demand, but it is not easy to make a decision regarding the right amount of resources. Indeed, proper provisioning of the resources to applications is an important issue in IaaS cloud computing. Most web applications encounter large and fluctuating task requests. In predictable situations, the resources can be provisioned in advance through capacity planning techniques. But in case of unplanned and spike requests, it would be desirable to automatically scale the resources, called auto-scaling, which adjusts the resources allocated to applications based on its need at any given time. This would free the user from the burden of deciding how many resources are necessary each time. In this work, we propose an analytical and efficient VM-level scaling scheme by modeling each VM in a data center as an M/M/1 processor sharing queue. Our proposed VM-level scaling scheme is validated via a numerical experiment.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.3
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• pp.114-128
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• 2013

Greenhouse gas emissions have been an important issue in different countries because of their effects on global warming. The government has to organize greenhouse gas reduction measures suitable to regional characteristics by establishing annual implementation plans and comprehensive policies based on the UNFCCC. The transportation sector is one of the major contributors of air pollution; hence increasing need to estimate current and future traffic emissions precisely. Under these circumstances, a number of emission models have been developed recently. However, current methods of estimation cannot carry out effective analyses because it does not reflect vehicle movement characteristics. This study aims to present a new method for calculating road traffic emissions in Goyang city. A travel demand model is utilized to carry out GHG emission estimates according the traffic data (fleet composition, vehicle kilometers travelled, traffic intensity, road type, emission factors and speed). This study evaluates two approaches to estimate the road traffic emissions in Goyang City: Pollution-Emis and the Handbook of Emission Factors for Road Transport (HBEFA v.3.1) which is representative of the "average speed" and the "traffic situation" model types. The evaluation of results shows that the proposed emission estimation method may be a good practice if vigilant implementation of model inputs is observed.

• Journal of Korean Home Economics Education Association
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• v.15 no.3
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• pp.1-12
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• 2003

The purpose of this study is to provide basic information for the development of Creative Discretionary Activity Program to Home Economics teachers. The need scales were developed based on the development characteristics of adolescence and data was collected from 521 middle school students in the seoul. The results are as fallows. 1. Among the seven areas self-understanding and career explorations showed the highest degree of demand. and the area of family relationship and friendship and maladjustment of adolescents followed, knowledge about sex and manner awareness took the lowest position. 2. Finding potential ability, understanding aptitude and personality. understanding IQ and EQ, solution of character showed the highest degree of demand. and solution of stress, interest identification. changing society and new career followed. 3. Demands for Creative Discretionary Activity showed significant difference according to socio-demographic variables such sex, family types and economic levels.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.127-132
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• 2011

Worldwide, the building energy simulation becomes inevitable step for predicting the energy consumption in building. In simulation process, the expertise is required for the accurate analysis results. In Korea, however, most of user use the inconsistent data with Korea circumstance. In this step, we need to construct the standard input data matched building in Korea. In this study, electricity consumption of apartments in Daejeon is analyzed. The yearly data of a apartment complexes of 2009 are analyzed as monthly, daily(week and weekend), timely, and completion year. With this result, we are able to predict the demand pattern of electricity in a house and make the schedule by demand pattern. The results of this study are followed. The averaged amount of electricity consumption in winter is higher than summer because of the high capacity of heating equipment. All of the house has electric base load from 0.26kWh to 0.5kWh. The average of the electricity consumption of month is shown as 326.7kWh. A week is seperated as 4 part such as week, weekend, Saturday and Sunday. During week, the average of timely electricity consumption is shown as 0.442kWh. The Saturday consumption is 0.453kWh. The Sunday is 0.461kWh.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.933-940
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• 2018

The conversion of the internal combustion engine vehicle to the electric vehicle is suggested as a solution to the problem of global climate change and environmental pollution. Accordingly, this study was started to promote the use of electric vehicles. The purpose of this study is to identify the basic background knowledge and current status of electric vehicles in Korea and abroad, and expand from previous understanding on which factors affect ones choice on electric vehicles by considering individual characteristics and context in detail. In the analysis, a set of demand forecasting models were constructed by grouping the respondents based on the household characteristics as well as the vehicle ownership. At the time in need for better understanding of the feasibility of electric vehicles, it is expected that the research can assist the promotion of electric vehicles. In the follow-up study, I would like to continue the research on the activation of electric vehicles.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.1-11
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• 2019

The Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) predicted that recent extreme hydrological events would affect water quality and aggravate various forms of water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed and sunlight) were established using the Representative Concentration Pathways (RCP) 8.5 climate change scenario suggested by the AR5 and calculated the future runoff for each target period (Reference:1989-2015; I: 2016-2040; II: 2041-2070; and III: 2071-2099) using the semi-distributed land use-based runoff processes (SLURP) model. Meteorological factors that affect water quality (precipitation, temperature and runoff) were inputted into the multiple linear regression analysis (MLRA) and artificial neural network (ANN) models to analyze water quality data, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (T-N) and total phosphorus (T-P). Future water quality prediction of the Anseongcheon River basin shows that DO at Gongdo station in the river will drop by 35% in autumn by the end of the $21^{st}$ century and that BOD, COD and SS will increase by 36%, 20% and 42%, respectively. Analysis revealed that the oxygen demand at Dongyeongyo station will decrease by 17% in summer and BOD, COD and SS will increase by 30%, 12% and 17%, respectively. This study suggests that there is a need to continuously monitor the water quality of the Anseongcheon River basin for long-term management. A more reliable prediction of future water quality will be achieved if various social scenarios and climate data are taken into consideration.

• Environmental and Resource Economics Review
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• v.31 no.1
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• pp.31-50
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• 2022

This paper estimates the price of standard waste bags that satisfies the polluter pays principle. Unlike previous studies, this paper suggests a method that can find new equilibrium prices using a structural relationship between the demand and cost function for the wastes. To do this, we employ the fixed-point iteration. The main findings of this paper are as follows. Assuming that the polluter pays principle is achieved at the average cost for the waste treatment, the price need to be set at a level about 3.12 times higher than the current one. The estimation result using a structural model, however, shows that the price should be set at a level four times higher than the present. This results are because the quantities reduced of the wastes make the cost per quantity of wastes due to the fixed costs increase. If applying the estimated price to the demand function, the amount of discharge of waste generated nationwide can be reduced by 10%.