• Journal of the Korean Operations Research and Management Science Society
• /
• v.38 no.3
• /
• pp.23-35
• /
• 2013

It is very important that the calculation of railroad track capacity in infrastructure investment analysis and train operation planning. The dwelling time is one of the factors that influence in railroad track capacity. Current research in dwelling time has been focusing on theoretical investigation, the state of the research in effective variable (dwelling time etc) is insufficient. In this paper, we clearly draw the concept of railroad track capacity and the estimate on modeling of relationship railway demand and dwelling time. Also, we compare and analyze the variation of railroad track capacity according to transit railway demand in Gyeongin Line (Guro~Inchon). This paper is expected to contribute for improving on the in-using equations and methods in train operation planning as well as for improving level of service on railway user.

• Advances in Energy Research
• /
• v.7 no.2
• /
• pp.85-100
• /
• 2020

Distributed energy resources (DERs) are essential for coping with growing multiple energy demands. A microgrid (MG) is a small-scale version of the power system which makes possible the integration of DERs as well as achieving maximum demand-side management utilization. Hence, this study focuses on the analysis of optimal power dispatch considering economic aspects in a multi-carrier microgrid (MCMG) with price-responsive loads. This paper proposes a novel time-based demand-side management in order to reshape the load curve, as well as preventing the excessive use of energy in peak hours. In conventional studies, energy consumption is optimized from the perspective of each infrastructure user without considering the interactions. Here, the interaction of energy system infrastructures is considered in the presence of energy storage systems (ESSs), small-scale energy resources (SSERs), and responsive loads. Simulations are performed using GAMS (General Algebraic modeling system) to model MCMG, which are connected to the electricity, natural gas, and district heat networks for supplying multiple energy demands. Results show that the simultaneous operation of various energy carriers, as well as utilization of price-responsive loads, lead to better MCMG performance and decrease operating costs for smart distribution grids. This model is examined on a typical MCMG, and the effectiveness of the proposed model is proven.

• Journal of Korea Multimedia Society
• /
• v.7 no.4
• /
• pp.592-600
• /
• 2004

A recommendation system, which is an application area of e-CRM in e-commerce environment, provides individualized goods recommendation service that meets the demand of individual users. In general, existing recommendation systems require extensive historic user information in application domains. However, the method of recommendation based on static historic user information needs to respond flexibly to users'demand that changes rapidly and sensitively over time and in domains including a variety of users. In addition, it is difficult to recommend for new users who are not fall into any of existing domains. To overcome such limitations and provide flexible recommendation service, this study designed and implemented CPAR (Customer Preference Analysis Recommender) system that supports customer preference analysis and filter management. The filtering management capacity of the present system eases the necessity of extensive information about new users. In addition, CPAR system was implemented in XML-based wireless Internet environment for recommendation service independent from platforms and not limited by time and place.

• Journal of Korean Society of Transportation
• /
• v.28 no.2
• /
• pp.171-181
• /
• 2010

The integrated transit fare system of Seoul metropolitan area has given positively evaluated with reduction of user cost and activating the transfer behavior from its opening year, July 2007. However, there were only few research about railway demand forecasting methodology, especially mode share, has conducted under the integrated fare system. This study focuses on the utility estimation by each mode under the integrated fare system, and on the coefficient actualization relates on travel time and travel cost estimation with Household Travel Survey Data 2006. Also the railway demand analysis methodology under various fare systems is presented. The methodology from this study is expected to improve accuracy and usefulness in railway demand analysis.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.39 no.6
• /
• pp.877-886
• /
• 2019

The size of the subway entrance should be calculated according to the user's demand, but Korea has the same size for each entrance by applying a uniform value. Recently, the installation of mobile convenience facilities such as escalators, elevators, etc. is mandated by the traffic weakness promotion law, but it is inconvenient to use the existing stations because it is mainly arranged in the place where it can be installed regardless of user demand. This study aims to establish a model for estimating the size of mobile convenience facilities by predicting the use demand of each station entrance so that the location and size of mobile facilities can be reflected in the design or construction of the station. To this end, a multiple regression model was established to forecast daily demand by utilizing the demand for getting on and off by station and the building association area for each purpose around the railway station. The actual data of Dongdaemun and Jonggak Stations were used to verify the estimated model. In addition, the escalator installation scale was compared / analyzed by doorway using domestic and overseas escalator equations. As a result, it was more accurate to estimate the usage demand for a single station. Also, Jonggak Station has an up and down escalator installed at exit 1, but it was analyzed that it is appropriate to install at exit 4. This study is an advanced form of the essay model for estimating the users of the entrance and exit users of urban railway stations published in 2018. In addition, it seems to be the basis of the current escalator installation criteria.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.8
• /
• pp.1-7
• /
• 1999

The Internet is emerging as a powerful tool in the area of information and communication technology. The WWW has been especially contributed to increase the internet demand because of its browser which has "Graphic User Interface". Nowadays number of hosts that supply harmful information such as pornographic materials, and the infringement of human rights is rapidly increased. Access to such materials is very easy. Therefore security system which will protect young users from access to harmful host is needed. This paper presents implementation of user system has database about harmful hosts at the Internet and monitors that the user traffic over LAM get touch with the hosts. The system can not make the user access the harmful host because it can over LAN. The performance analysis on the developed system monitoring the traffic over LAN of Andong university is carried out. The performance analysis of monitoring results satisfies with preventing users from the connection to the internet harmful sites.

• Plant Journal
• /
• v.15 no.1
• /
• pp.31-37
• /
• 2019

In this study, to improve the accuracy of forecast of heat demand in the district heating system, this study applied heat demand performance among the main factors of district heating demand forecast in Pankyo area as the heat sales information of the user facility instead of existing heat source facility heat supply information, and compared the existing method with the accuracy based on the actual value. As a result of comparing the difference of the forecasts values of the existing and changed methods based on the performance values over the one week (2018.01.08 ~ 01.14) during the hot water peak, the relative error decreased from 7% to 3% The relative error between the existing and revised forecasts was 9% and 4%, respectively, for the five-month cumulative heat demand from February to February 2018, Also, in case of the weekend where the demand of heat is differentiated, the relative error of the forecasts value is consistently reduced from 10% to 5%.

• Journal of Environmental Science International
• /
• v.19 no.8
• /
• pp.1057-1066
• /
• 2010

An ecological learning center is defined as a place which can establish the correct relationship between human and environment. Human can learn ecosystem and importance of environment throughout observation of nature and participation in program of ecological learning center. The most important aspects of ecological learning center planning are to reflect on user's demand and preservation of ecosystem. The prime goals of this study is to analyze user's characteristics in the Young Wheol Mulmurigol Ecological Learning Center. The second goal of this study is to find out the satisfaction model based on user's perceived performance of each program and facility in the center. For this study, questionnaire survey with 204 individuals was completed. The data from the questionnaire were analyzed statistical method by SPSS. There are several significant results from the study as following First, this ecological learning center as a newly operating facility is used not for educational purpose but for resting and relaxation purpose. It is due to that the most of users in this center are package tourists with historic scenes. Second, user's perceived performance evaluated by 23 attributions of programs and facilities, and these attributions could be classified by 5 factors such as environment friendly design, educational function, preservation of environment, provision of various bio-top and provision of resting area. Third, the user satisfaction model indicates that user satisfaction is depended on various factors such as preservation of environment, provision of various bio-top, provision of resting area. Among these factor affecting the satisfaction, provision of various bio-top is the most influence on user satisfaction.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.10 no.1
• /
• pp.47-53
• /
• 2014

LTE-Advanced is the evolved version of LTE which is currently in progress at the 3GPP. At present, as the number of smart phone users is rapidly increasing, the demand for ever more capacity is driven largely by video usage and high quality data communication and so on, this let more researchers study about LTE-A all over the world. LTE-A aims to achieve improved service and communication quality over 3G system at the aspect of throughput, peak data rate, latency, and spectral efficiency. Among various features in LTE-A, the multi-user MIMO(MU-MIMO), in which the base station transmits several streams to multiple receivers, has expected to give better quality for system. In this paper, we investigate performances of various types of downlink receivers with fixed number of antennas. we first review the development process from LTE to LTE-A. Second we introduce TM9 which is adopted in Rel.10 for MU-MIMO system, including the MU-MIMO system model and the explanation on the algorithm used in system. We also have brief introduction about sub-blocking in turbo decoding, finally we compare the performance between the uncoded case and coded case which is using turbo encoding.

• The Journal of Industrial Distribution & Business
• /
• v.9 no.5
• /
• pp.47-62
• /
• 2018

Purpose - Based on preceding studies, this thesis focuses on the finding of the definition and category of mobile tourism application and deriving out its characteristics. And after looking for how they make influences on continuous intention to use, we make empirical study with TAM model. Research design, data, and methodology - There are many Chinese tourist who visit Korea with user's constant intention to use of tourism application. This study is to find out the definition and category of mobile tourism application through research of preceding study and to fomulate the research model and hypothesis that how tourism application attributes (convenience, interaction, accessibility, local basis, security) affect constant intention to use of mobile tourism application. In order to verify a hypothesis, we conducted a survey for Chinese users of tourism application. In empirical study, we analyzed a structure model for frequency analysis, reliability analysis, exploratory factor analysis, validity analysis through IBM SPSS Statistics 21.0 and IBM SPSS AMOS 21.0 Results - Among tourism applications, convenience, interaction, accessibility and local basis have positive effects on both perceived usefulness and perceived easiness respectively. But security does not. Also perceived easiness has a positive effect on perceived usefulness. Finally, perceived usefulness and perceived easiness have positive effect on constant intent to use. Conclusions - Tourism application enterprises should put emphasis on design such as menu or function in order to simplify the operation of new services for new customers. Therefore, comfortable user interface and development of useful function can improve tourism application. Consequently, it leads to the promotion of tourism application. Also, when users perceive tourism application as a useful media which is easy, comfortable and useful content, the degree of constant intention to use becomes increased. It is important to provide plentiful and useful contents for customers and to develop user interface such as easy operation because these factors have positive effects on constant demand and use of tourism application.