• Journal of KIISE
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• v.42 no.10
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• pp.1268-1279
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• 2015

In order to manage a large number of devices connected to the Internet of Things (IoT), the Internet Engineering Task Force (IETF) proposed the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). The route of the RPL network is generated through the use of an Objective Function (OF) that is suitable for the service that is required for the IoT network. Since the route of the RPL network is conventionally simply chosen only by considering the link quality between the nodes, it is sensible to seek an OF that can also provide better Quality of Service (QoS). In previous studies, the end-to-end delay might possibly be sub-optimal because they only deal with problems related to the reduction of energy consumption and not to the link quality on the path to the sink node. In this study, we propose a scheme that reduces the end-to-end delay but also gives full consideration to both the quality on the entire route to the destination and to the expected lifetime of nodes with bottlenecks from heaped traffic. Weighting factors for the proposed scheme are chosen by experiments and the proposed scheme can reduce the end-to-end delay and the energy consumption of previous studies by 20.8% and 10.5%, respectively.

• Journal of Plant Biotechnology
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• v.31 no.3
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• pp.231-237
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• 2004

Oxycarotenoids are oxygenated carotenoids that perform critical roles in plants. $\beta$-Carotene hydroxylase adds hydroxyl groups to the $\beta$-rings of carotenes and has been cloned from several bacteria and plants including Arabidopsis. This study was carried out to investigate the effect of $\beta$-carotene hydroxylase gene (Chyb) on the oxycarotenoids biosynthesis in the transgenic Arabidopsis. Construct of pGCHYB containing Chyb was established onto Gateway vector system (pENTR3C gateway vector and pH2GW7 destination vector). Arabidopsis thaliana (cv. Columbia) was transformed with Agrobacterium tumerfacience GV3101 harboring pGCHYB construct driven by 35S promoter and hygromycin resistant gene. Seven hundred bases paired PCR products, indicating the presence of Chyb gene, were found in the transformants by PCR analysis using Chyb primers. Hygromycin resistance assay showed that transgenes were stably inherited to next generation. The overexpression of the Chyb gene resulted in the decrease carotenoid content. Especially, astaxanthin unusual oxycarotenoid in wild type Arabidopsis was detected in the transgenic plants. This means that decreased carotenoids might be converted into astaxanthin metabolism with the aid of silent gene in the host.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.89-102
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• 2006

The purpose of this paper is to develop a dynamic OD estimating model to overcome the limitation of depicting teal situations in dynamic simulation models based on static OD trip. To estimate dynamic OD matrix we used the hybrid discrete choice model(called the 'Demand Simulation Model'), which combines travel departure time with travel mode and travel path. Using this Demand Simulation Model, we deduced that the traveler chooses the departure time and mode simultaneously, and then choose his/her travel path over the given situation In this paper. we developed a hybrid simulation model by joining a demand simulation model and the supply simulation model (called LiCROSIM-P) which was Previously developed. We simulated the hybrid simulation model for dependent/independent networks which have two origins and one destination. The simulation results showed that AGtt(Average gap expected travel time and simulated travel time) did not converge, but average schedule delay gap converged to a stable state in transportation network consisted of multiple origins and destinations, multiple paths, freeways and some intersections controlled by signal. We present that the hybrid simulation model can estimate dynamic OD and analyze the effectiveness by changing the attributes or the traveler and networks. Thus, the hybrid simulation model can analyze the effectiveness that reflects changing departure times, travel modes and travel paths by demand management Policy, changing network facilities, traffic information supplies. and so on.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.7-19
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• 2006

Due to the continuous expansion of the highway, the opening of the high-speed railway(KTX), etc, the demands of domestic air transport decreasing. In the circumstances, airports and local governments are spending themselves in taking a measure to activate local airports. In this aspect, this study seeks the smooth flow of human movement through the activation of Daegu International Airport by analyzing the present condition of Daegu International Airport in relation to the appearance of the high-speed railway, deducing plans for activating airports, and presenting the roadmaps for long-, mid- and short-term roles for the development of Daegu Airport, and Presents substantial fulfilling plans to secure the competitive power of Daegu International Airport by speeding up the flow of air goods of the area for the long run. It is suggested in the study that by setting up an organization exclusively responsible for activating Daegu International Airport in the city of Daegu, supporting local travel agencies to promote consistent demands, supporting aviation companies to employ Daegu International Airport as a major air base, establishing airlines with priority for airports that open newly in local cities of Japan and establishing and expanding airlines in China areas be promoted actively. Ministry of Construction & Transportation makes it a means of main airport Policy to only support Incheon International Airport to be a hub. However not only Incheon International Airport should be an amok representing the country, but also the wide Metropolitan area should supply the demands, and airports based in the West and East Coast areas need to be developed in the future. It is suggested that since air demands of domestic local airports are based on the demands of the of gin destination in neighboring region, multiple bases need to be developed. It is suggested that by developing not 1 in mega hub (Incheon International Airport) but 1 in mega hub. 2 in regional hub (the West and East Coast) and Jeju foy the tourism hub in our developing airports system.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.121-130
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• 2004

In these days, multiple-path generation method is highly demanded in practice and research areas, which can represents realistically travelers behavior in choosing possible alternative paths. The multiple-path generation algorithm is one of the key components for policy analysis related to ATIS, DRGS and ATMS in ITS. This study suggested a method to generate multiple Possible paths from an origin to a destination. The approach of the suggested method is different from an other existing methods(K-shortest path algorithm) such as link elimination approach, link penalty approach and simulation approach. The result of the multi-label vine-building shortest path algorithm(MVA) by Kim (1998) and Kim(2001) was used to generate multiple reasonable possible paths with the concept of the rational upper boundary. Because the MVA algorithm records the cost, back-node and back-back node of the minimum path from the origin to the concerned node(intersection) for each direction to the node, many potential possible paths can be generated by tracing back. Among such large number of the potential possible paths, the algorithm distinguishes reasonable alternative paths from the unrealistic potential possible paths by using the concept of the rational upper boundary. The study also shows the very simple network examples to help the concept of the suggested path generation algorithm.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.135-146
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• 2004

For improving the effectiveness of travel information, some rational paths are needed to provide them to users driving in real road network. To meet it, k-shortest path algorithms have been used in general. Although the k-shortest path algorithm can provide several alternative paths, it has inherent limit of heavy overlapping among derived paths, which nay lead to incorrect travel information to the users. In case of considering the network consisting of several turn prohibitions popularly adopted in real world network, it makes difficult for the traditional network optimization technique to deal with. Banned and penalized turns are not described appropriately for in the standard node/link method of network definition with intersections represented by nodes only. Such problem could be solved by expansion technique adding extra links and nodes to the network for describing turn penalties, but this method could not apply to large networks as well as dynamic case due to its overwhelming additional works. This paper proposes a link-based shortest path algorithm for the travel information in real road network where exists turn prohibitions. It enables to provide efficient alternative paths under consideration of overlaps among paths. The algorithm builds each path based on the degree of overlapping between each path and stops building new path when the degree of overlapping ratio exceeds its criterion. Because proposed algorithm builds the shortest path based on the link-end cost instead or node cost and constructs path between origin and destination by link connection, the network expansion does not require. Thus it is possible to save the time or network modification and of computer running. Some numerical examples are used for test of the model proposed in the paper.

• Journal of Korean Society of Transportation
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• v.33 no.2
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• pp.113-124
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• 2015

The KOTI(Korea Transport Institute) released the new version of KTDB(Korea Transport DataBase) in public. The new KTDB is different from the past KTDB in using the concept of trip generation and trip attraction instead of using the concept of Origin-Destination (OD), which was used in the past KTDB. Thus, the appropriate analysis method for future travel demand became necessary for the new type of KTDB. The method should be based on the concept of PA(Production-Attraction). This study focused on analysis of trip generation and trip distribution related to newly generated trips by future land developments. The study also described clearly the standardized forecasting process and methods with PA travel tables. The study showed that the analysis results with OD-based analysis can be different from the results with PA-based analysis in forecasting travel demand for a simple example case even though they used exactly same orignal travel data. Therefore, this study emphasized that a proper method should be applied with the new PA-based KTDB. It is necessary to prepare and disseminate guidelines of the proper forecasting method and application with PA-based travel data for practician.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.81-88
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• 2008

This paper presents the travel demand estimation using interval estimation methods during the trip generation stage, and then followed the other three stages of the four stage trip estimation. We have used real data of Dae-jun City. To estimate travel demand using the interval estimation method, a reliability level was set to 95% by a upper bound value, a middle value and a lower bound value. The four stage traffic demand analysis procedure was equally applied and finally interval traffic was estimated. The result showed a difference between maximum values and middle values depending on the destination during the trip generation stage. It depends on an explanation ability of regression analysis. Most of interval estimation ratio resulted in the traffic assignment stage showed ${\pm}5{\sim}18%$ difference on the average and ${\pm}30{\sim}50%$ at the most.

• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.203-215
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• 2018

This study suggests a method to construct large scale dynamic O/D reflecting the characteristic that the passengers' travel patterns change according to the land use patterns of the destination. There are limitations in the existing research about dynamic O/D estimation method, such as the difficulty of collecting data, which can be applied only to a small area, or limiting to a specific transportation network such as highway networks or public transportation networks. In this paper, we propose a method to estimate dynamic O/D without limitation of analysis area based on transportation resources that can be easily collected and used according to the big data era. Clustering analysis was used to calculate the departure time trip distribution ratio based on arrival time and departure time trip distribution function was estimated by each cluster. As a result of the comparison test with the survey data, the estimated distribution function was statistically significant.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.72-84
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• 2017

This study aims to investigate how the service quality of a farm party affects the cognitive and emotional images of the farmhouse and revisit intentions by designing a research model and testing hypotheses. First, findings of the test show that when it comes to service quality, the physical environment and program contents of farm party have an effect on the cognitive image of the farmhouse while the qualification of party operators does not. Second, the physical environment of the party and party operator's qualification affect the emotional image but the program contents has no effect. Third, The cognitive and emotional images have an effect on the revisit intentions. It is certain that the farm party serves as cultural contents facilitating the rural economy and an emerging business model in the rural tourism. When we approach the farm party as a business model to provide service, not cultural contents as party, however, farmhouses may build a positive image as a new tourist destination and also see their economy facilitated. This study looks into Seoul and Gyeonggi areas and thus is geographically limited and does not cover national phenomenon.