• Journal of Distribution Research
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• v.7 no.1
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• pp.1-20
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• 2002

Many of logistics-related research in automobile industry has focused on inbound logistics and procurement. Research into outbound logistics is relatively few. As a starting research into outbound logistics in automobile industry, this paper examined its logistics network problems with three aspects - location strategy, inventory strategy and transportation strategy. We proposed alternatives of logistics network design resolution, and presented three practical scenarios based on those alternatives. Based on interview, on-site visit and internal data collection processes, we identified major domestic outbound logistics problems such as redundant logistics bases, inefficient delivery policy, insufficient inventory capacity, inventory stock quality deterioration, inefficient transportation system, and etc. In order to cope with those problems, we proposed such strategic alternatives as introduction of hub-and-spoke system, integration of logistics bases, introduction of (automatic) parking building, diversification of transportation mode, and etc. At the same time, we constructed three practically executable scenarios based on those ideas. The first is "Center Hub" scenario, the second is "Metropolitan Hub" scenario. The third and last scenario is "Regional Consolidation of Warehouses (distribution centers)".

• Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.33-39
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• 2011

The vibration characteristic of tires is one of very important issues which heavily affect the noise and comfort on driving. Therefore, when the new tire is designed, the vibration characteristic of tire should be considered. In this paper, the vibration characteristic of non-pneumatic tire is investigated for geometric of NPT which is designed by cell angle of spoke. The analysis is based on the finite element method and used ABAQUS program, which is able to non-linear analysis. The material of NPT is used for the Ogden energy model, which is model of hyperelastic material. This paper investigate natural frequency and modal of NPT and compare result of NPT with it of pneumatic tire.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.329-330
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• 2022

태평양 도서국은 간선항로와 먼 거리, 적은 물동량, 수출입 불균형 등으로 해상운임이 높게 형성되어 있으며, 기후변화에 취약하여 항만운영에 제약이 많은 등 해상운송이 상당히 열악한 실정이다. 또한 해상운송 의존도가 상당히 높은 반면, 정기선 연계정도는 상당히 낮아 해운물류 경쟁력을 향상 필요성이 증대되고 있다. 따라서 본 연구에서는 사회연결망분석(SNA)를 통해 14개 태평양 도서국의 국가 간 해상교역 구조를 파악하고 이를 통해 해상운송망 강화를 위한 방안을 제시하였다. 분석 결과, 대상국가 간 교역구조는 점차 복잡해지고 있으며, 점차 피지, 사모아, 파푸아뉴기니 등을 중심으로 Hub-spoke 체제의 해상운송 네트워크가 형성되고 있다. 역내 해상운송망 강화를 위해서는 분석결과에서 도출된 역내 주요 항만을 환적항으로 개발하여 해상운송 연계성을 강화하고, 카보타지 허용을 통한 정기선 입항빈도 증대, 인프라 개선을 통한 항만 운영탄력성 강화 등이 필요하다.

• Applied Microscopy
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• v.50
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• pp.13.1-13.7
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• 2020

We examined the morphology of fertilized egg and ultrastructures of fertilized egg envelopes of Ancistrus cirrhosus belong to Loricariidae using light and electron microscopes. The fertilized eggs formed a mass on the spawning place and were yellowish, spherical, non-transparent, demersal, adhesive, and a narrow perivitelline space. But, the adhesiveness of fertilized eggs was disappeared after spawning excluding contact parts. The micropyle with funnel shape was surrounded by 15-19 furrow lines of egg envelope in a spoke-like pattern. The outer surface of egg envelope has smooth side and inner surface of egg envelope was rough with grooves. Also, the total thickness of the fertilized egg envelope was about 32.58 ± 0.85 ㎛ (n = 20), and the fertilized egg envelope consisted of three layers, an outer adhesive electron-dense layer, a middle layer with low electron density and an inner electron-dense layer with grooves in counter structure from other most teleost. Collectively, these morphological characteristics and adhesive property of fertilized egg, and ultrastructures of micropyle, outer surface, and section of fertilized egg envelope are showed species specificity.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.197-204
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• 2007

Busan Port has been facing critical situation in terms of container handling volume, especially growth rate of transshipment(T/S) container of the year of 2006 was at a standstill. Annual average growth rate of T/S container during the period of 2003 to 2006 slowed down to 7.7% while it recorded over 34% to the period of 1999 to 2002. It has mainly resulted from the change of circumstance of Northeast Asian ports, that is, firstly mega carriers' increasing direct call to Northern Chinese ports such as Qingdao, Tianjin and Dairen effected to T/S container volume of Busan port, secondly start to operate deep-water port of Shanghai, thirdly Japanese super hub port project to handle their local containers at domestic ports. This paper aims to analyze the T/S type of inter-routes and hub and spoke and statistical status of Busan port. The purpose of the paper is to propose new concept which is to attract T/S container utilizing hub port function of Busan port in Northeast Asia It is that mega carriers are given dedicated terminals to use Busan port as T/S base in the region.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.1-8
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• 2013

This study focuses on a ship detection and tracking method using Frequency Modulated Continuous Wave (FMCW) radar used for horizontal surveillance. In general, FMCW radar can play an important role in maritime surveillance, because it has many advantages such as low warm-up time, low power consumption, and its all weather performance. In this paper, we introduce an effective method for data and signal processing of ship's detecting and tracking using the X-band radar. Ships information was extracted using an image-based processing method such as the land masking and morphological filtering with a threshold for a cycle data merged from raw data (spoke data). After that, ships was tracked using search-window that is ship's expected rectangle area in the next frame considering expected maximum speed (19 kts) and interval time (5 sec). By using this method, the tracking results for most of the moving object tracking was successful and those results were compared with AIS (Automatic Identification System) for ships position. Therefore, it can be said that the practical application of this detection and tracking method using FMCW radar improve the maritime safety as well as expand the surveillance coverage cost-effectively. Algorithm improvements are required for an enhancement of small ship detection and tracking technique in the future.

• Journal of Advanced Navigation Technology
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• v.1 no.1
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• pp.81-94
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• 1997

The construction of Incheon International Airport(IIA) was planned in order to meet the national air transport demand which has been rapidly increased, and to be a major hub airport in Northeast Asia. However, it is inevitable to compete with Japanese airports because Japanese government also planned to expand greatly the airport capacity in Tokyo area and Kansai Airport in Osaka area. Since a hub airport should have convenient connecting flights to spoke cities, it is required for IIA to have plenty of short-haul flights to the cities around Seoul, for example, to the cities in East China, Japan and other East Asian countries. IIA authority and Korean national air carriers should coordinate to develop air transport demand for short-haul international route and establish efficient hub-spoke flight schedules. This would be a essential precondition to function as a hinterland hub in Northeast Asia. Reflecting the geographical position, the function as a hourglass hub could be possible, if IIA is utilised by major airlines as a bridge to connect passengers between cities in Southeast Asia and 'cities in North America. To be a successful hourglass hub, the Korean national carriers must try to engage in the joint operations or the alliances with the major airlines of Southeastern countries or North American countries. All of these could be accomplished through the cooperation among government, airport and national air carriers.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.456-467
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• 2019

In this study, the discrete element method was used to simulate the excavation of spoke-type shield TBM. The horizontal stress coefficient was used for the ground to simulate the increase of the horizontal stress according to the depth, and the driving conditions were set based on the torque generated from the cutterhead of the TBM to excavate within the operating range. That is, when the value of the torque generated at the cutterhead exceeds the given operating condition, the speed of excavation is constantly reduced, and conversely, the method of increasing the speed of excavation is considered. The change speed of the excavation was given the minimum change requirement in consideration of the driver's review time, and the change was possible according to the excavation conditions. In order to use these conditions, the user-subroutine was considered separately, and the results show that the DEM model were able to analyze the excavation within the considered operating range.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.1029-1044
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• 2017

The Discrete Element Method (DEM) is one of the useful numerical methods to analyze the behavior of the ground formation by computing the motion and interaction using particles. The DEM has not been applied in civil engineering but also a wide range of industrial fields, such as chemical engineering, pharmacy, material science, food engineering, etc. In this study, to review a performance of the spoke-type earth pressure balance (EPB) shield TBM (Tunnel Boring Machine), the commercial software based on the DEM technology was used. An analysis of the TBM during excavation was conducted according to two pre-defined excavation conditions with the different rotation speed of a cutterhead. During the analysis, the resistant torque at the face of the cutterhead, the compressive force at the cutterhead and shield surface, the muck discharge at the screw auger were measured and compared. Upon the two kinds of excavation conditions, the applicability of the DEM analysis was reviewed as a modelling method for the TBM.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.328-340
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• 2019

Purpose: To generate phase images with free of motion-induced artifact and susceptibility-induced distortion using 3D radial ultrashort TE (UTE) MRI. Materials and Methods: The field map was theoretically derived by solving Laplace's equation with appropriate boundary conditions, and used to simulate the image distortion in conventional spin-warp MRI. Manufacturer's 3D radial imaging sequence was modified to acquire maximum number of radial spokes in a given time, by removing the spoiler gradient and sampling during both rampup and rampdown gradient. Spoke direction randomly jumps so that a readout gradient acts as a spoiling gradient for the previous spoke. The custom raw data was reconstructed using a homemade image reconstruction software, which is programmed using Python language. The method was applied to a phantom and in-vivo human brain and abdomen. The performance of UTE was compared with 3D GRE for phase mapping. Local phase mapping was compared with T₂* mapping using UTE. Results: The phase map using UTE mimics true field-map, which was theoretically calculated, while that using 3D GRE revealed both motion-induced artifact and geometric distortion. Motion-free imaging is particularly crucial for application of phase mapping for abdomen MRI, which typically requires multiple breathold acquisitions. The air pockets, which are caught within the digestive pathway, induce spatially varying and large background field. T₂* map, that was calculated using UTE data, suffers from non-uniform T₂* value due to this background field, while does not appear in the local phase map of UTE data. Conclusion: Phase map generated using UTE mimicked the true field map even when non-zero susceptibility objects were present. Phase map generated by 3D GRE did not accurately mimic the true field map when non-zero susceptibility objects were present due to the significant field distortion as theoretically calculated. Nonetheless, UTE allows for phase maps to be free of susceptibility-induced distortion without the use of any post-processing protocols.