• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.105-114
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• 2016

With approximately 20 million transportation card data entries of the metropolitan districts being generated per day, application of the data to management and policy interventions is becoming an issue of interest. The research herein attempts a model of the possibility of dynamic demand change predictions and its purpose is thereby to construct a Dynamic Passengers Trip Assignment Model. The model and algorithm created are targeted at city rail lines operated by seven different transport facilities with the exclusion of travel by bus, as passenger movements by this mode can be minutely disaggregated through card tagging. The model created has been constructed in continuous time as is fitting to the big data characteristic of transport card data, while passenger path choice behavior is effectively represented using a perception parameter as a function of increasing number of transfers. Running the model on 800 pairs of metropolitan city rail data has proven its capability in determining dynamic demand at any moment in time, in line with the typical advantages expected of a continuous time-based model. Comparison against data measured by the eye of existing rail operating facilities to assess changes in congestion intensity shows that the model closely approximates the values and trends of the existing data with high levels of confidence. Future research efforts should be directed toward continued examination into construction of an integrated bus-city rail system model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.857-865
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• 2016

This study analyzes 'willingness to have passenger cars' through perception survey about car use and possession. Social problems caused by increasing car use are serious. Because of the fact that 78.9% of registered vehicles are passenger cars and 75.3% of passenger cars are private cars, passenger cars are main reason of Social problems caused by using a car. So, we need to analyze the reason why people possess cars and need additional cars. Also we need to study about 'willingness to possess additional cars' through analysis of perception about car use and ownership. According to survey results, most households possess cars as means of commute, and most households need additional cars as means of commute to office, leisure, kids' commute to school and academy. Also we used Structural Equation Model to analyze car use and 'willingness to possess additional cars' according to ownership. Analysis results showed that car use is positively impacted by driving and usage perception, and negatively impacted by social problems such as parking, traffic congestion, traffic environment, and etc. Also, results showed that the number of car is positively impacted by usage perception, and negatively impacted by expenses. In case of 'willingness to have additional cars', is positively impacted by intention to use cars and negatively impacted by car ownerships. We think research results can be used as basic data to manage traffic demand.

• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.518-531
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• 2004

This paper discusses a testbed architecture for implementing scalable service differentiation in the Internet. The differentiated services (DiffServ) testbed architecture is based on a model in which a bandwidth broker (BB) can control network resources, and the ALTQ can reserve resources in a router to guarantee a Quality of Service (QoS) for incoming traffic to the testbed. The reservation and releasemessage for the ALTQ is contingent upon a decision message in the BE. The BB has all the information in advance, which is required for a decision message, in the form of PIB. A signaling protocol between the BB and the routers is the COPS protocol proposed at the IETF. In terms of service differentiation, a user should make an SLA in advance, and reserve required bandwidth through an RAR procedure. The SLA and RAR message between a user and the BB has implemented with the COPS extension which was used between a router and the BB. We evaluates the service differentiation for the video streaming in that the EF class traffic shows superb performance than the BE class traffic where is a network congestion. We also present the differentiated service showing a better packet receiving rate, low packet loss, and low delay for the EF class video service.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.64-71
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• 2010

When Handoff occurs at wireless network, existing AP search chooses one of various APs according to signal strength information. However, IEEE 802.11 uses Medium Access method with CSMA/CA that competes to obtain a channel by sharing medium. Therefore, network performance is heavily affected by the number of nodes and network congestion aside from signal strength. This scheme presented an additional AP selection indicator and a new handoff algorithm to realize handoff guaranteeing the network performance of mobile node in a process selecting new AP. This indicator is includes a handoff cost function reflecting the network information of mobile node, and the mobile node made handoff guaranteeing the network performance using network information possible by using this. also we classified the nodes into high-speed node and low-speed node. Then, when Handoff occurs, high-speed node was made itself choose AP by signal strength information. We also made the low-speed node choose its AP by using AP network information which is applied area. Hence, we demonstrate through simulation that gets an improvement in performance, even in the wireless network which many users concurrently access to, and it has considerable effects on aspects of resources and network management by distribution of users.

• Journal of the Korean Society for Railway
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• v.11 no.1
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• pp.81-94
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• 2008

Recently, most of countries have been adopting the policies that aim to deal with the Problems of road congestion, environmental problems and the decreasing the volume of rall. A vital important subject is the reform of railways. Actually, the reform of railways has been carried out in various kind of ways, however the most epoch-making policy has been privatization of railways. Historically, Japan made the first step when it carried out regional privatization, unifying the infrastructure and operation. It created a 6 passenger enterprises and 1 freight enterprise. Meanwhile, in the case of the UK, discussion about rail privatization started the middle of 1980 and was implemented in 1994. It was implemented according to a functional division based on a separation of infrastructure and operation, creating a lot of different enterprises. With regard to the UK and Japan, there have been some debates about the methods of privatization, in particular, some scholars suggest that the rail accidents in the UK are a result of division of the infrastructure and operation. In addition to, some insist that the accident which occurred on 27th April 2005 at Hukujiyama in Japan was also attributable to the emphasis on profitable management. This paper examines the process and outcomes of rail privatization between the UK and Japan, especially focusing on different methods of privatization. This paper may provide some lessens for rail privatization policy. First, the rail privatization policy needs a enough time to complete the scheme. Second it is require to participate in the consumer, mass communication and rail of ncers who are involved the operation. Third, it is essential to have a huge investment, high technology and strong organization to drive.

• Journal of Sasang Constitutional Medicine
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• v.23 no.3
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• pp.340-350
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• 2011

1. Objectives: This clinical study was conducted to understand the differences between Sasang constitutional types and to identify the physical symptoms presentation specific to each Sasang constitutional type. 2. Methods: In this descriptive study, 2,629 subjects (1,061 Taeeum-type, 683 Soeum-type, 885 Soyang-type) were surveyed between Nov 1, 2007 and Jul 31, 2010. The subjective symptoms experienced by the subjects were collected using a Physical Symptoms questionnaire, and the subjects were interviewed by Sasang specialists who determined the subjects' constitutional type. The data (in crude number and percentage) was analyzed on the general characteristics, Sasang constitutional type, and physical symptoms using the SPSS 17.0 software. The symptomatic presentation in men and women were analyzed on Sasang constitutional distribution using the chi-square test. 3. Results: 1) The physical symptoms specific to each Sasang constitutional type were as follows: 'frequent aphthous lesions in the oral cavity', 'lingering fatigue after sleep', 'headache', 'common cold symptoms presenting as loss of appetite or indigestion', and 'physical deterioration presenting as problems with digestion' in the Soeum type; 'physical deterioration presenting as problems in perspiration' and 'swelling and puffiness' in the Taeeum type; and 'excessive forgetfulness' in the Soyang type. 2) The physical symptoms specific to each Sasang constitutional type in men were as follows: 'Unilateral or bilateral headaches, 'frequent aphthous lesions in the oral cavity', 'common cold symptoms presenting as rhinorrhea or nasal congestion', 'common cold symptoms presenting as loss of appetite or indigestion', and 'physical deterioration presenting as problems with digestion' in the Soeum type; and 'swelling and puffiness' in the Taeeum type. 3) The physical symptoms specific to each Sasang constitutional type in women were as follows: 'common cold symptoms presenting as headaches', 'common cold symptoms presenting as loss of appetite or indigestion', 'physical deterioration presenting as problems with digestion' in the Soeum type; and 'pain in knees', 'redness of eyes', 'dryness of mouth', 'common cold symptoms presenting as coughing', 'physical deterioration presenting as problems in perspiration', 'swelling and puffiness' in the Taeeum type. 4. Conclusions: This study demonstrates that physical symptoms present in constitutional type-specific patterns. Understanding of the personal Sasang constitutional type and systematic, personalized healthcare based on constitutional typology is anticipated to contribute to improved health management strategy.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.191-197
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• 2018

With a population of more than 10 million people worldwide, MegaCity was only three in 1975, but it is expected to grow to 24 in 2013 and more than 30 in 2025 and more than 3 billion worldwide by 2050 It is expected to be absorbed into smart city. Especially in Asia and Africa, urbanization is expected to proceed rapidly. As the urbanization progresses and the population living in the cities increases, there are various problems such as rapid increase of energy consumption, congestion of traffic, various aging of the infrastructure and the like. As a result, smart city is emerging as a new alternative for solving urban problems. Smart City is rapidly expanding with the development of related technologies and can improve costs, improve urban services, improve quality of life, productivity and sustainability. Therefore, this paper analyzes the size and trend of the domestic and overseas smart city market, and analyzes the smart city related policies, trends and case studies of major countries to see the development status and market of smart city related industries, Present a business utilization model.

• Archives of Plastic Surgery
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• v.41 no.4
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• pp.387-393
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• 2014

Background Reconstruction of ischial pressure sore defects is challenging due to extensive bursas and high recurrence rates. In this study, we simultaneously applied a muscle flap that covered the exposed ischium and large bursa with sufficient muscular volume and a profunda femoris artery perforator fasciocutaneous flap for the management of ischial pressure sores. Methods We retrospectively analyzed data from 14 patients (16 ischial sores) whose ischial defects had been reconstructed using both a profunda femoris artery perforator flap and a muscle flap between January 2006 and February 2014. We compared patient characteristics, operative procedure, and clinical course. Results All flaps survived the entire follow-up period. Seven patients (50%) had a history of surgery at the site of the ischial pressure sore. The mean age of the patients included was 52.8 years (range, 18-85 years). The mean follow-up period was 27.9 months (range, 3-57 months). In two patients, a biceps femoris muscle flap was used, while a gracilis muscle flap was used in the remaining patients. In four cases (25%), wound dehiscence occurred, but healed without further complication after resuturing. Additionally, congestion occurred in one case (6%), but resolved with conservative treatment. Among 16 cases, there was only one (6%) recurrence at 34 months. Conclusions The combination of a profunda femoris artery perforator fasciocutaneous flap and muscle flap for the treatment of ischial pressure sores provided pliability, adequate bulkiness and few long-term complications. Therefore, this may be used as an alternative treatment method for ischial pressure sores.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.135-142
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• 2010

The convenient techniques for predicting the bus arrival time have used the data obtained from the buses belong to the same company only. Consequently, the conventional techniques have often failed to predict the bus arrival time at the downstream bus stops due to the lack of the data during congestion time period. The primary objective of this study is to overcome the weakness of the conventional techniques. The estimation model developed based on the data obtained from Bus Information System(BIS) and Bus management System(BMS). The proposed model predicts the bus arrival time at bus stops by using the data of all buses travelling same roadway section during the same time period. In the tests, the proposed model had a good accuracy of predicting the bus arrival time at the bus stops in terms of statistical measurements (e.g., root mean square error). Overall, the empirical results were very encouraging: the model maintains a prediction job during the morning and evening peak periods and delivers excellent results for the severely congested roadways that are of the most practical interest.

• Land and Housing Review
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• v.5 no.4
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• pp.235-246
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• 2014

In the late 1980s, 5 new towns such as Bundang, Ilsan, Pyeongchon, Sanborn, Jungdong were constructed to solve housing problems and to disperse functions concentrated within Seoul. As the city got matured, it began to appear the initial signs of urban problems such as aging of high rise-density apartment sites, traffic congestion, lack of parking spaces and aging of infrastructure. Therefore, in order to cope with urban problems, it is very important to apprehend the process of urban growth, its change and the feature of physical/human elements. So, the purpose of this thesis is to analyze the changes in housing and population characteristics for past 20 years by use of Census data from 1995 to 2010. First, the new town's goal of population and housing plan at the time of construction was analyzed how it was achieved, and it is close to the performance of the goal. And the trend of changes in the population and household characteristics was analyzed by every five year's data. As the result of analysis, it shows socio-demographic changes such as aged and elderly population growth, rapid increase in one generation's household and single person household, highly educated city, monthly rent household's increase and charter household's reduction. Results of this analysis can be utilized to aforethought management of new towns. But it is required more sustained and systematic urban monitoring and data analysis because the one-off analysis of the city's characteristics alone is difficult enough to grasp them.