• Journal of Institute of Convergence Technology
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• v.10 no.1
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• pp.7-12
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• 2020

We describe a efficient surface reconstruction method that reconstructs a 3D manifold polygonal mesh approximately passing through a set of 3D oriented points. Our algorithm includes 3D convex hull, octree data structure, signed distance function (SDF), and marching cubes. The 3D convex hull provides us with a fast computation of SDF, octree structure allows us to compute a minimal distance for SDF, and marching cubes lead to iso-surface generation with SDF. Our approach gives us flexibility in the choice of the resolution of the reconstructed surface, and it also enables to use on low-level PCs with minimal peak memory usage. Experimenting with publicly available scan data shows that we can reconstruct a polygonal mesh from point cloud of sizes varying from 10,000 ~ 1,000,000 in about 1~60 seconds.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.3
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• pp.299-309
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• 2016

This study proposed a logistics plan for sending supply to be distributed to areas other than producing areas to wholesalers and allocating supply to be distributed to areas near producing areas to local distribution center in the vicinity instead of shipping the entire quantity to wholesalers for fruits auction to increase the competitive edge of the domestic fruits and vegetables logistics market in the ear of infinite competition. A video auction-based short distance division logistics operation model was developed to enhance competitiveness related to the circulation of fruits and vegetables, reduce logistics costs, and rationalize logistics by distributing the items sent to wholesalers through field auction and the shipments at local distribution center to neighboring areas through video auction connected to wholesalers real-time. The study especially came up with a logistics rationalization plan by examining and analyzing the stages and costs of transportation between producing areas and wholesalers on the circulation routes of fruits.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.333-335
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• 2001

In this paper, an algorithm for fault location in Auto Transformer(AT) Feeding Railway system is presented. If a fault occurs at the AT feeding circuits of electrical railway system, it is very important to find fault location and to remove it immediately for the purpose of ensuring safety for transportation. Because the characteristics of reactance-distance are not linear, only using one terminal signals to give fault distance is difficult. In this paper, first, using the KVL, 4 voltage equation are obtained. Secondly, eliminating voltage a distance equation which consists of currents at rail and line parameters including mutual effects.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.53-60
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• 2022

In this study, the conceptual design and performance evaluation of a personal air vehicle (PAV) is presented, which is a potential futuristic individual transportation. The blade element theory (BET) is employed to compute a rotational velocity. A computational fluid dynamics (CFD) simulation is performed to investigate the difference in the thrust performance in the rotor axis distance of a quad-copter PAV in hovering. Modal analysis is performed to create a Campbell diagram to investigate critical speed. Consequently, a quad-copter PAV changes the aerodynamics thrust and critical velocity according to the rotor axis distance.

• Korean Journal of Heritage: History & Science
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• v.45 no.3
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• pp.100-113
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• 2012

In the midst of recent active excavation, lots of Silla(新羅) roof-end tiles are unearthed in Yeongnam area(嶺南地域). These are confirmed the same tile frame as the Silla tiles excavated in Gyeongju(慶州). It is represented by the Silla tiles excavated in Ingaksa Temple(麟角寺) excavation research. Roof-end tile with arabesque design(唐草文平瓦當) etc. including roof-end tile with lotus design(蓮花文圓瓦當) are judged to be the tile frame produced by the same frame of roof-end tile that was excavated in Gyeongju, Wolseong(月城) and Hwangyongsa Temple(皇龍寺址). There are three kinds of cases concerning the transportation of tile manufacture ; the roof-end tile manufactured in Gyeongju directly moved to each region, only tile frame moved to site to be manufactured there, and tile manufacturer moved to site to manufacture there. This article considers the case of the roof-end tile manufactured in Gyeongju that was directly moved to each region. In case of the Silla tiles excavated in region especially Ingaksa Temple, the aspects of tiles in accordance with different era show the repeated coexistence, expansion and maintenance. This situation is significant as a clue to understand the supply from Gyeongju not as temporary, but as continuous. On the other hand, if the Gyeongju tiles flowed directly into each region, and if the road was built of gravels and the means of transportation was cart, the damage from movement must never be prevented. On the contrary, transportation through waterway might be advantageous due to the reduction of labor and damage rate and the easiness of loading. Accordingly, it tells us why the ruins where roof-end tiles were excavated located near big and small rivers or streams. Of course there are some ruins located in a fixed distance, but the distance may be enough to endure the impact put on tiles from the overland movement. Therefore, in case of direct inflow form long distance, transportation must be finished by overland movement after waterway movement.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.101-108
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• 2004

The new transit fare in the Seoul Metropolitan is basically determined based on the distance-based fare system (DBFS). The total fare in DBFS consists of three parts- (1) basic fare, (2) transfer fare, and (3) extra fare. The fixed amount of basic fare for each mode is charged when a passenger gets on a mode, and it proceeds until traveling within basic travel distance. The transfer fare may be added when a passenger switches from the present mode to another. The extra fare is imposed if the total travel distance exceeds the basic travel distance, and after that, the longer distance the more extra fare based on the extra-fare-charging rule. This study proposes an algorithm for finding minimum fare route in DBFS. This study first exploits the link-label-based searching method to enable shortest path algorithms to implement without network expansion at junction nodes in inter-modal transit networks. Moreover, the link-expansion technique is adopted in order for each mode's travel to be treated like duplicated links, which have the same start and end nodes, but different link features. In this study, therefore, some notations associated with modes can be saved, thus the existing link-based shortest path algorithm is applicable without any loss of generality. For fare calculation as next steps, a mathematical formula is proposed to embrace fare-charging process using search process of two adjacent links illustrated from the origin. A shortest path algorithm for finding a minimum fare route is derived by converting the formula as a recursive form. The implementation process of the algorithm is evaluated through a simple network test.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.1
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• pp.43-49
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• 2000

The heat transportation from a complex of industry to a rural area needs more efficient method because the distance between them is usually more than 10km. Conventional heat transportation using steam or hot water via pipe line has limits in transportation distance (about 3~5 km) because of the heat loss and frictional loss in the pipe line. Metal hydride can absorb or discharge hydrogen through exothermic or endothermic reaction. After releasing hydrogen from metal hydride by means of the waste heat from industry, we can transport this hydrogen to urban area via pipe line. In urban areas, other metal alloy reacts with this hydrogen to form metal hydride and produces heat for heating. Cool heat is also obtained if it is possible to use metal hydride with low reaction temperature. Therefore, metal hydride can be used as a media for transportation and storage of heat. $MmNi_{4.5}Al_{0.5}Zr_{0.003}$, $LaNi_5$, $Zr_{0.9}Ti_{0.1}Cr_{0.6}Fe_{1.4}$, $MmNi_{4.7}Al_{0.1}Fe_{0.1}V_{0.1}$ alloys were selected for this purpose and the properties of those metal hydrides were discussed. The design and control techniques were proposed and discussed for this heat transportation system using metal hydride.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.75-82
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• 2005

To relieve congestion in the current system of intercity transportation, the Korea decided in 1990 to construct a high-speed railroad between Seoul and Busan and it is now in operation. This new mode of transportation significantly cut travel time between major cities and a trip from Seoul to the southeastern port of Busan. Since the KTX opening, average daily passenger numbers on both the Gyeongbu and Honam lines have increased about 1.3 fold over 2003 levels. As of December 2004, the KTX trains are carrying about 81,000 people a day. On KTX routes, the daily number of airline passengers dropped. Express long-distance bus traffic also dropped by 20% to 30%, while that on short-distance routes (100km or less) increased by about 20%. These figures clearly indicate that the Korean transportation network is becoming railroad-centric. However, the number of KTX passengers is fewer than anticipated possibly due to the Korean economic downturn and the operation of the KTX will leave many existing Saemaul and Mugunghwa train sets idle, which will be put into operation for areas, not covered by the KTX. When all the existing major lines have been electrified, more high-speed rail services will be phased in using direct connections to maximize operational efficiency. And also, the dual management by KTX and conventional rail will be regarded as the promotion of the benefit of the public.

• The Journal of Information Systems
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• v.31 no.3
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• pp.47-65
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• 2022

Purpose With the recent development of Big Data and Artificial Intelligence technology, self-driving technology has developed into three stages (partial self-driving) or four stages (conditional self-driving), it is expected to bring a new paradigm to transportation in the city. Although many researchers are researching related technologies, there is no research on self-driving for disabled persons. In this study, the basic research was conducted based on the assumption that the shared self-driving car used by the disabled person is similar to the special transportation currently driving. Design In this study, data analysis and machine learning techniques were utilized to analyze the mobility patterns of disabled persons by type and to search for leading factors affecting the traffic volume of special transportation. Findings The study found that external physical disorders and developmental disorders often visit general welfare centers, internal organ disorders often visit general hospitals, and the elderly and mental disorders have various destinations. In addition, machine learning analysis showed that the main transportation routes for the disabled person use arterial roads and auxiliary arterial roads and that the ratio of building usage-related variables affecting the use of special transportation for a disabled person is high. In addition, the distance to the subway and bus stops was also mentioned as a meaningful variable. Based on these analysis results, it is expected that the necessary infrastructure for shared self-driving cars for disability person traffic will be used as meaningful research data in the future.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.362-366
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• 2014

In recent years, a permanent magnet linear synchronous motor (PMLSM) has been used in various kinds of transportation applications for its relative high power density and efficiency. The general transportation system arranges the armature on the full length of transportation lines. However, when this method is applied to long distance transportation system, it causes increase of material cost and manufacturing time. Thus, in order to resolve this problem, we suggested stationary discontinuous armature PMLSM. However, the stationary discontinuous armature PMLSM contains the edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem because the cogging force that they exert bad influences the controllability of the motor. Therefore, in this paper we proposed the combination of skewed magnets and stair shape auxiliary teeth to reduce the force by edge effect. Moreover, we analyzed the influence of the design factors by using a 3-D finite element method (FEM) simulation tool.