• Horticultural Science & Technology
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• v.17 no.2
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• pp.118-122
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• 1999

Quality changes of fruit vegetables were investigated during simulated export and marketing to find out the optimum shipping temperature. Fruit vegetables were loaded into a small refrigerated-container and kept for four days at various temperatures, and fruit quality was assayed immediately after harvest, 4 days after storage and 4 days after marketing at ambient temperature. In 'Back Seong Ilho' cucumber fruits, fresh weight loss was further reduced at $13^{\circ}C$ and $11^{\circ}C$ than at $15^{\circ}C$ and room temperature. Soluble solid contents remained at relatively lower levels when cucumbers were stored at $13^{\circ}C$ and $11^{\circ}C$. In 'Chun Ryang' eggplant fruits, fresh weight loss was greatly increased at all the temperatures (room, $12^{\circ}C,\;9^{\circ}C,\;and\;6^{\circ}C$). However, flesh browning, a primary quality factor of eggplant fruit, was most effectively inhibited at $9^{\circ}C$, whereas chilling injury occurred in fruit flesh at $6^{\circ}C$. Water loss of 'Eals Seinu' melon fruits was most inhibited and soluble solid contents at harvest were maintained for the longest period at $4^{\circ}C$. In 'Pe Pe' cherry tomatoes, storage at $10^{\circ}C$ and $7^{\circ}C$ seemed to more effectively inhibit metabolic changes and the incidence of cracking, the severest disorder than room temperature. But the fruits stored at $10^{\circ}C$ contained higher level of soluble solids than those at $7^{\circ}C$. The overall results suggest that the optimum shipping temperature range is 11 to $13^{\circ}C$ for cucumbers, around $9^{\circ}C$ for eggplant fruit, $4^{\circ}C$ for melons, and $10^{\circ}C$ for cherry tomatoes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4D
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• pp.323-330
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• 2010

The time in port for vessels is one of the important factors for analyzing the operation status and the capacity of ports. In addition, the time in port for vessels can be directly used for estimating the greenhouse gas emissions resulted from vessels in port. However, it is unclear which variables can affect the time in port for vessels and what the marginal effect of each variable is. With these challenges in mind, the study analyzes the time in port for vessels arriving and departing port of Busan by using a parametric survival model. The results show that the log-logistic accelerated failure time model is appropriate to explain the time in port for 19,167 vessels arriving and departing port of Busan in 2008, in which the time in port is significantly affected by gross tonnage of vessels, service capacity of terminal, and vessel type. This study also shows that the greenhouse gas emission resulted from full-container vessels, which accounted for about 61% of all vessels with loading/unloading purpose arriving and departing port of Busan in 2008, is about "17 ton/vessel" in the boundary of port of Busan. However, the hotelling greenhouse gas emissions resulted from non-container vessels (3,774 vessels; 20%) are greater than those from the full-container vessels. Hence, it is necessary to take into account more efficient port management polices and technologies to reduce the service time of non-container vessels in port of Busan.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.501-508
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• 2005

The purpose of this paper is to present the alternatives for improving coostal shipping logistics system to be a logistic hub-nation with a competitive edge. For this purpose, major environmental factors in Northeast Asia and accordingly its effects are analyzed And then the effects of coastal shipping system's development strategy is analysed using Structural Equation Model and Multiple Regression Model. Research results show that three types of coastal shipping development strategy( connected transportation system, structure of coastal shipping system, governmental support policy) will contribute much to being a logistics hub-nation. From the results, some implications are derived as follows. Firstly, environmental-friendly balanced ocean-coastal transport system is required Secondly, a excusive feeder port, Ro-Ro ship & high-speed ship are necessary to establish the one-stop logistics service system Finally, governmental support policy and subsidy(tax-exempted oil & various tax benefits) are required to reactivate lagged coastal shipping system to be a logistic hub-nation with a competitive edge.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.1
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• pp.157-165
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• 1998

This paper considers the single-product production and transportation problem with discrete time, dynamic demand and finite time horizon, an extension of classical dynamic lot-sizing model. In the model, multiple freight container types are allowed as the transportation mode and each order (product) placed in a period is shipped immediately by containers in the period. Moreover, each container has type-dependent carrying capacity restriction and at most one container type is allowed in each shipping period. The unit freight cost for each container type depends on the size of its carrying capacity. The total freight cost is proportional to the number of each container type employed. Such a freight cost is considered as another set-up cost. Also, it is assumed in the model that production and inventory cost functions are dynamically concave and backlogging is not allowed. The objective of this study is to determine the optimal production policy and the optimal transportation policy simultaneously that minimizes the total system cost (including production cost, inventory holding cost, and freight cost) to satisfy dynamic demands over a finite time horizon. In the analysis, the optimal solution properties are characterized, based on which a dynamic programming algorithm is derived. The solution algorithm is then illustrated with a numerical example.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.138-138
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• 2018

선박을 통한 해상수송은 세계 무역의 80% 이상을 차지하고 있으며, 대부분의 선박은 저질중유의 연소로부터 추진력을 발생시키는 디젤 엔진을 원동력으로 사용하고 있다. 이러한 디젤 엔진은 연소의 부산물로 매년 백만 톤 이상의 오염물질을 방출하는데, 그 주성분은 탄소로 이루어져 있고 고온 열분해 또는 압축 점화 엔진의 작동 부산물들이 소량 포함되어 있다. 이에 본 연구에서는 선박으로부터 배출된 폐 수트를 리튬이온전지용 도전재로 활용하기 위한 독특한 방법이 제안되었다. 실험에 사용된 폐 수트는 운항중인 컨테이너선으로부터 수집되었으며, 수집된 폐 수트는 탄소 성분 이외의 불순물을 제거하고 흑연화 정도를 개선시키기 위해 $2,000^{\circ}C$로 열처리되었다. 열처리된 폐 수트의 모폴로지를 확인하기 위해 투과전자현미경을 이용하여 그 형상을 관찰하였으며, 이를 통해 폐 수트의 일차 입자는 지름이 약 70-100 nm 정도인 양파껍질 모양의 탄소(carbon nano-onion)로 형성된다는 것이 확인되었다. 또한, XRD, RAMAN 분광법 및 BET 분석 결과를 통해, 열처리된 폐 수트가 결정성이 있는 흑연으로 재형성되었으며 비표면적은 일반적으로 사용되는 활물질에 비해 약간 더 높다는 것을 확인할 수 있었다. 한편, 이러한 특성은 리튬이온전지용 도전재로 활용될 수 있는 가능성을 보여주었고, 이는 전기화학적 정전류 충전 및 방전 테스트를 통해 그 성능이 확인되었다. 일반적으로 사용되는 도전재의 테스트 결과와 폐 수트를 도전재로 사용한 테스트 결과를 Fig. 1에 나타내었다. 이상의 실험 결과들을 미루어 볼 때, 선박으로부터 배출된 폐 수트가 리튬전지용 음극 활물질 및 도전재로 재활용될 수 있을 것으로 사료된다.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1765-1768
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• 2009

Honam area is one of the under-industrial areas in Korea and because of this it has low weight in the total container transportation in Korea. Also the railway distance from honam area to the main container ports like Busan port and Gwangyang port is so short that the portion of rail container transportation occupies about 10 percent in total container transportation amount in Honam area. But on the contrary of those situations, 1st step Jangsung inland container depot (ICD) was finished as one of the main logistics facilities in Korea and 2nd Jangsung inland container depot is under construction. To promote rail container transportation in Honam area which has shortage of container transportation demand, it is necessary to give adequate transport service to the client. So, this research studied some methods for promoting rail container transportation in Honam area. The subject of survey is freight agent and survey items are selected to find the present situation of rail container transportation in Honam area. And from the survey results various strategies will be suggested to promote rail container transportation in Honam area.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.171-178
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• 2002

At the present time, container transportation plays a key role in the international logistics and the efforts to increase the productivity of container logistics become essential for Korean trucking companies to survive in the domestic as well as global competition. This study suggests an approach for determining fleet size for container road transportation with dynamic demand. Usually the vehicles operated by the transportation trucking companies in Korea can be classified into three types depending on the ways how their expenses occur; company-owned truck, mandated truck which is owned by outsider who entrust the company with its operation, and rented vehicle (outsourcing). Armually the trucking companies should decide how many company-owned and mandated trucks will be operated considering vehicle types and the transportation demands. With the forecasted monthly data for the volume of containers to be transported a year, a heuristic algorithm using tabu search is developed to determine the number of company-owned trucks, mandated trucks, and rented trucks in order to minimize the expected annual operating cost The idea of the algorithm is based on both the aggregate production planning (APP) and the pickup-and-delivery problem (PDP). Finally the algorithm is tested for the problem how the trucking company determines the fleet size for transporting containers.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.569-576
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• 2021

Radar is a ground defense system that detects enemy aircraft and receives power from a mobile power supply in an emergency. Serious problems may occur if the equipment is damaged by impact during transportation for use. The US military standard MIL-STD-810H contains information on environmental tests such as shock and vibration applied to munitions. Therefore, in this study, the transient analysis of ANSYS 19.2 was performed using the impact data specified in MIL-STD-810H as an input value. Through this, the maximum stress generated in the impact environment of the mobile power supply container was derived, and the safety margin was calculated to confirm the reliability of the container.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.559-566
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• 2001

The sway control problem of the pendulum motion of a container hanging on the trolly, which transports containers from a container ship to trucks, is considered in the paper. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration, deceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, the trolley motion control strategy is introduced and applied. In this paper, we introduce and synthesize a new type of swing motion control system in which a small auxiliary mass is installed on the spreader. The actuator reacting against the auxiliary mall applies inertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we apply the $H^{\infty}$ based gain-scheduling control technique to the anti-swing motion control system design problem of the controlled plant. In this control system, the controller dynamics are adjusted in real-time according to time-varying plant parameters. And the simulation result shows that the proposed control strategy is shown to be useful for the case of time-varying system and, robust to disturbances such as winds and initial sway motion.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.92-92
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• 2009

조선업을 포함한 다양한 산업 분야에서 후판 강재의 수요량 증가와 함께 사용 범위 또한 폭넓게 되고 있다. 특히, 선박의 수송효율의 극대화를 위하여 컨테이너선의 대형화가 급속하게 진행되고 있으며, 2009년 현재1,300TEU 이상의 초대형 컨테이너선이 건조되고 이다. 이처럼 용접구조물의 초대형화에 따른 사용강재 또한 고강도 극후물화 되고 있다. 현재 선박에 적용중인 고강도 강재는 EH47 강재로 YP 460MPa 급의 강재가 Hatch Coamming부에 적용중에 있으며, 강재의 두께 또한 70mm 이상이다. 이러한 고강도 극후물재의 강구조물에 적용에 따른 선급협회에서는 용접부에서의 취성균열 전파에 의한 취성파괴의 위험성이 있으므로 강재의 두께를 제한하고 더욱 엄격한 파괴인성값을 요구하고 있다. 일본선급협회(NK)를 중심으로 취성균열의 정지를 위한 모재의 요구 성능등에 관한 연구들이 진행되고 있다. 이 연구의 대부분의 전제 조건은 선박의 블럭과 블럭의 조립시에 용접부가 직선형이 아닌 계단형(Butt shift)를 하는 것으로 하고 있으므로, 국내의 조선건조 공법의 현실과는 거리감이 있다. 본 연구에서는 국내 조선사에서 수행중인 직선 이음부에 대한 시공 공법에서 취성균열이 발생하여 진전 되더라도 균열을 정지 시킬 수 있는 기술에 관한 연구를 수행하였다. 균열의 진전은 대부부의 연속면에서는 정지를 시키지 못하고 직진 전파 하여서 파괴에 도달하게 된다. 따라서 뭔가의 불연속적인 면을 임의로 생성하여야 균열을 정지 시킬 수 있다. 본 연구에서는 이러한 균열의 정지 방법으로 형상적인 측면과 재료적인 측면에서 검토를 수행하였다. 형상적인 측면에서는 균열을 정지 시키고자 하는 위치에 불연속적인 면을 만들기 위하여 일정 크기의 hole을 만들어서 균열을 정지시켰으며, 재료적인 측면에서는 고인성의 용접재료를 사용하여서 취성균열이 진행하는 경로에 인성을 높은 재료를 적용하여 불연속적인 면의 생성과 함께 인성을 높여서 균열을 정지 시키는 기술을 개발하였다. 이러한 기술의 개발을 통하여 취성균열의 전파에 의한 파괴를 방지 할 수 있으며, 용접구조물의 안전성 확보를 가능하게 하였다.