• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.44-57
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• 2019

It is crucial to understand how people make decisions on mode choice and to accurately predict their behaviors in transportation planning. One of avenues for advancing modeling is, in particular, taking into account for taste heterogeneity in modeling that can incorporate different decision-making processes across group. In this study, we hypothesize that how people make decisions on mode choice would differ by destination in that land use characteristics are heterogeneous by zone even if zones are all in the same area. To this end, we apply Latent Class Modeling (LCM) to commute trips in Seoul by using 2010 household travel diary survey, investigate types of latent classes with the aid of characteristics of destination, and analyze how those classes differently response to factors. The LCM identifies two classes: in the first one, modal split of auto and public transit (bus and metro) is almost half-and-half and the trip destinations are characterized by relatively more residence facilities and less business/commercial facilities; in the second one, public transit has a notably high share and trip destinations are characterized by relatively more business/commercial facilities. In addition, it turns out that demographic and socio-economic variables affect mode choice differently by class.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.119-128
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• 2008

Weather like rain, strong wind or snowfall may make the road condition deteriorated and sometimes induce traffic accidents, which lead to severe traffic congestion, thereby travelers may change their destinations elsewhere. Although origin-destination trip information is required to analyze transportation planning in urban area, there are little researches on the relationship between weather condition and travel patterns. This paper investigates the characteristics of travel patterns on expressway in rainy days of 2006. We compare the normal travel patterns with those of rainy days by the travel distance for each vehicle type. Results show that traffic volume and travel distance have been reduced in rainy days as we expect, and also show different travel patterns for weekday and weekend.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.1
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• pp.33-40
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• 2017

In this Paper, Analyse the Steady State Behavior of TCP and TFRC with Packet Error when both TCP and TFRC Flows Co-exist in the Network. First, Model the Network with TCP and TFRC Connections as a Discrete Time System. Second, Calculate Average Round Trip Time of the Packet Between Source and Destination on Packet Loss Environment. Then Derive the Steady State Performance i.e. Throughput of TCP and TFRC, and Average Buffer Size of RED Router Based on the Analytic Network Model. The Throughput of TCP and TFRC Connection Decrease Rapidly with the Growth of Sending Window Size and Their Transmission Rate but Their Declines become Smoothly when the Number of Sending Window Arrives on Threshold Value. The Average Queue Length of RED Router Increases Slowly on Low Transmission Rate but Increases Rapidly on High Transmission Rate.

• Journal of the Korean Geographical Society
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• v.48 no.4
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• pp.545-556
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• 2013

This study sets up nodal regions for shopping and leisure with 424 district units located in Seoul and examines the characteristics of the vertical structure and the regional system. According to the higher-order analysis result, the trip for leisure forms a greater part, and about each of the nodal regions of the first stratum, major spots for origin and destination are located in the center, and those spots are connected to adjacent district units located nearby. As the factor's eigenvalue is bigger, the spatial range gets greater, too, and is located in outsides. And in the third or higher strata, either linkage between Gangnam and Gangbuk or leapfrogging linkage according to the bipolar factors is distinctive. Linkage between nodal regions centering around Jongro-gu, Jung-gu, Gangnam-gu, or Yeoungdeungpo-gu is not distinct, and in particular, the nodal regions of Jongro Geumcheon are maintained as the upper strata being independent from other nodal regions from the second or higher strata.

• Journal of the Korean Geographical Society
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• v.50 no.2
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• pp.203-216
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• 2015

This paper examined the changes of urban system through the network and the flow pattern reflected in daily movement in Korea. Because daily movement reflects trip pattern, urban system formed by inter-city linkages can be recognized in terms of living sphere. While population movements between cities have the number of linkage systems of city network and the number of traffic regions composed of the origin and destination has increased respectively. Nevertheless, spatial extent of Capital region and Busan region has been expanded. In Gangwon-do in which Seoul-oriented high-speed transportation network has developed, separation of living sphere between Yeongdong area and the Soyanggang cultural region formed around Chuncheon was intensified. Living sphere that includes Daejeon and the surrounding cities has been expanded to the southern Gyeonggi-do. The existing living sphere formed in Jeollanam-do was fragmented into the east and west around Mokpo and Suncheon due to the weakened centrality of Gwangju. Living spheres formed by spatial interaction were consistent with regional administrative boundary. Considering the increased interaction between Seoul and its surrounding cities, the development of global city-region centered on Seoul is expected.

• KIISE Transactions on Computing Practices
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• v.22 no.1
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• pp.38-43
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• 2016

Recent developments regarding transportation technology have positioned travel as a major leisure activity; however, trip-itinerary planning remains a challenging task for tourists due to the need to select Points of Interest (POI) for visits to unfamiliar cities. Meanwhile, due to the GPS functions on mobile devices such as smartphones and tablet PCs, it is now possible to collect a user's position in real time. Based on these circumstances, our research on an automatic itinerary-planning system to simplify the trip-planning process was conducted briskly. The existing studies that include research on itinerary schedules focus on an identification of the shortest path in consideration of cost and time constraints, or a recommendation of the most-popular travel route in the destination area; therefore, we propose a personalized itinerary-recommendation system for which the stay-time preference of the individual user is considered as part of the personalized service.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.99-106
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• 2017

With the increased interest in the quality of life of modern people, the implementation of the five-day working week, the increase in traffic convenience, and the economic and social development, domestic and international travel is becoming commonplace. Furthermore, in the past, there were many cases of purchasing packaged goods of specialized travel agencies. However, as the development of the Internet improved the accessibility of information about the travel area, the tourist is changing the trend to plan the trip such as the choice of the destination. Web services have been introduced to recommend travel destinations and travel routes according to these needs of the customers. Therefore, after reviewing some of the most popular web services today, such as Stubby planner (http://www.stubbyplanner.com) and Earthtory (http://www.earthtory.com), they were supposed to be based on traditional Traveling Salesman Problems (TSPs), and the travel routes recommended by them included some practical limitations. That is, they were not considered important issues in the actual journey, such as the use of various transportation, travel expenses, the number of days, and lodging. Moreover, although to recommend travel destinations, there have been various studies such as using IoT (Internet of Things) technology and the analysis of cyberspatial Big Data on the web and SNS (Social Networking Service), there is little research to support travel routes considering the practical constraints. Therefore, this study proposes a new mathematical model for applying to travel route recommendation service, and it is verified by numerical experiments on travel to Jeju Island and trip to Europe including Germany, France and Czech Republic. It also expects to be able to provide more useful information to tourists in their travel plans through linkage with the services for recommending tourist attractions built in the Internet environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5B
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• pp.509-516
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• 2009

The Stream Control Transmission Protocol(SCTP) is a reliable transport layer protocol that provides several features. Multihoming is the one of the features and allows an association(SCTP's term for a connection) between two endpoints to use multiple paths. One of the paths, called a primary path, is used for initial data transmission and in the case of retransmission an alternate path is used. SCTP's current retransmission policy attempts to improve the chance of success by sending all retransmissions to an alternate destination address. However, SCTP's current retransmission policy has been shown to actually degrade performance in many circumstances. It is because that, due to Karn's algorithm, successful retransmissions on the alternate path cannot be used to update RTT(Round-Trip Time) estimation for the alternate path. In this paper we propose a scheme to avoid such performance degradation. We utilize 2bits which is not used in the flag field of DATA and SACK chunks to disambiguate original transmissions from retransmissions and to keep RTT and RTO(Retransmission Time-Out) values more accurate.

• Industrial Engineering and Management Systems
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• v.8 no.2
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• pp.80-92
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• 2009

This paper addresses the inventory rationing issue embedded in the regional supply chain inventory replenishment problem (RSIRP). The concerned supply chain, which was fed by the national supply chain, consisted of a single warehouse distributing a single product to multiple stores (M-stores) with independent and normally distributed customer demand. It was assumed that the supply chain operated under the order-up-to level inventory replenishment system and had only one truck at the regional warehouse. The truck could make one replenishment trip to one store per period (a round trip per period). Based on current inventories and the vehicle constraint, the warehouse must make two decisions in each period: which store in the region to replenish and what was the replenishment quantity? The objective was to position inventories so as to minimize lost sales in the region. The warehouse inventory was replenished in every fixed-interval from a source outside the region, but the store inventory could be replenished daily. The truck destination (store) in each period was selected based on its maximum expected shortage. The replenishment quantity was then determined based on the predetermined order-up-to level system. In case of insufficient warehouse inventories to fulfill all projected store demands, an inventory rationing rule must be applied. In this paper, a new inventory rationing rule named Expected Cost Minimization (ECM) was proposed based on the practical purpose. The numerical results based on real data from a selective industry show that its performance was better and more robust than the current practice and other sharing rules in the existing literature.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.67-83
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• 2018

This research is motivated by the question, "Where, when, and through what mode does an individual passenger moving within a subway station use to travel from starting to final destinations ?" To answer this, the stations passed by the individual passenger, the path taken, and modes used need to be known beforehand. In the metropolitan integrated public transportation fare system, Automated Fare Collection System(AFC) can be a source of information on transit modes, stations, and paths of individual passengers. AFC calculates a fare for the passenger based on travel data such as boarding and alighting stations, time, and mode used. In this research, an Selected Station Analysis(SSA) method, in which AFC data is used to observe passenger movement in the metropolitan public transportation subway station from the perspective of subway transfer stations, is proposed. SSA subdivides individual passenger movement in transfer stations and analyzes initial station/time and final destination station/time information using the trip chain perspective.