• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.463-468
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• 2011

The prospect of Arctic trade transportation opening on a year-round basis creates a vast opportunity of exploring untapped resources and shortened navigational routes. However, the environment's remoteness and lack of technical experiences remains a big challenge for the maritime industry. With this, engine designers and makers are continually investigating, specifically optimizing propulsion shafting system design, to meet the environmental and technical challenges of the region. Further, classification societies recognize the need to upgrade the Unified Rules concerning elements to meet current Polar requirements. Hence in this paper, excitation torque calculation on Polar class vessels propulsion shafting system will be reviewed. The propeller - ice interaction load effect, which is a main consideration of excitation source of Polar Class propulsion shafting system, on shaft design calculation will be analyzed.

• 해양환경안전학회지
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• 제10권1호
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• pp.35-40
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• 2004

선박은 물을 떠날 수 없고, 항로의 자연환경에 따라 항행해야 하기 때문에 항행하는 해역환경에 의하여 선박의 특성이 결정된다. 중국의 남방과 북방의 해역은 상이한 특징을 가지고 있다. 즉 남방의 해역은 수심이 갚고, 북방의 해역은 수심이 얕다. 중국의 조선기술은 이러한 해역특성에 적응하여 상이한 선형이 발명, 발전되었다.

• Ocean and Polar Research
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• 제29권4호
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• pp.311-316
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• 2007

Ocean noise may be used for monitoring wind speed and rainfall rate on the sea surface, as well as for tracking whales' migration routes. In particular, low-frequency ocean noise has recently been of concern with relation to the behavior of marine mammals. Low-frequency ocean noise has been increasing over the past few decades due to increase of ship traffic and offshore oil industry activities. Mechanical noise such as flow noise and cable strumming noise may be induced if low-frequency ocean noise is measured by cabled traditional hydrophone in high current areas. To successfully measure low-frequency ocean noise in a shallow water environment with strong current, we developed a self-recording hydrophone. This paper describes the main configurations of the self-recording hydrophone and presents some results on measured data.

• 한국철도학회논문집
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• 제16권4호
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• pp.348-351
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• 2013

The aim of this research is to analyze and periodize the relationship between railroad and river transportation as one aspect of the transformation of the land transportation system in Korea. As a result, three phases can be observed: a first phase of equality and interdependence (1910s); a second phase, subordinating rivers to feeder lines under railroad's dominance; and a third phase when trucks and buses became a major means for local transportation in place of traditional shipping routes. River ports were among the main planned destinations during the first and second phases, but such plans were changed or withdrawn after the third phase. This relationship between river and rail illustrates one geopolitical factor relating to the development of Korea's rail transportation network.

• 한국국방경영분석학회지
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• 제16권2호
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• pp.105-117
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• 1990

In the transportation network problems, it is often more desirable to select multiple number of optimal parths to prepare for additional constratints being imposed than to choose single optimal path. This paper addresses 'the problem of finding the k-shortest paths visiting p-specified nodes in a network'. The solution method is derived and the example of application is shown. The keypoint for determining the k-shortest paths via p-specified nodes is to combine the Shier's k-shortest path algorithm and the principle of optimality of dynamic programming method. Finally, for a transportation network problem consisting of national main routes, the k-shortest paths via some specified cites are obtained by using the solution method developed here.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.161-162
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• 2009

In Korea there are Passenger ships on 106 routes running out of 10 port cities. These cities, such as Mokpo, Masan, Incheon, are the main transportation hubs the island residents today. But most passenger ship companies in Korea are limited in income and mostly small in size. These small companies have many challenges to overcome and are slow to improve services. Frequent service cancellations, aging sailors and a decline in service are contributing factors.

• Bulletin of the Korean Chemical Society
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• 제4권2호
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• pp.84-87
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• 1983

Transition state structures were calculated for A and M routes of ${\omega}$-alkenyl radical cyclization (n = 2∼4) using MINDO/3-RHF method. Results of our analysis of HOMO level changes indicated that the transition state stability is not controlled by the decoupling effect alone as Bischof suggested, but in greater degree it is determined by through-bond interaction of the HOMOs with the framework $HO-{\sigma}$ or $LU-{\sigma}^*$ orbitals. In case of larger n (n > 4), the product stability was considered to be the main cause of M route dominance in the cyclization.

• 한국항만경제학회지
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• 제18권2호
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• pp.91-108
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• 2002

The World has been rapidly changing into either technological aspects or perception of those who has utilised to the corresponding informational impact. Whatever areas we have actually been involved in are strongly connected with this evolution of informational technology in one way or another. Logistics is not a exception as well as trade. Two main routes in distribution channel such as commercial and physical flow of goods, have been operating in terms of I-business. In order to activate E-trade with E-commerce, E-logistics should be utilised and emphasized in more efficient and effective manner of doing job as a facilitator. So, in this paper, it studied the role of E-logistics to make E-trade better work as well as to look into present situations in E-commerce. Then, it was identified that some facilities as 3PL or shipping company have to adopt information in their business process with a view of valued add service providers. This means those who have implemented E-Logistics activities, should be more competitive in the market, only when they provide the value-added total logistics services.

• 산업경영시스템학회지
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• 제23권54호
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• pp.13-26
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• 2000

Machining route selection to produce parts should be based on shop flow information because of input data at scheduling tasks and is one of the main problem in process planning. This paper addresses the problem of machining route selection in multi-stage process with machine group included a similar function. The model proposed is formulated as 0-1 integer programing considering the relation of parts and machine table size, avaliable time of each machine for planning period, and delivery date. The objective of the model is to minimize the sum of processing, transportation, and setup time for all parts. Genetic algorithm approach is developed to solve this model. The efficiency of the approach is examined in comparison with the method of branch and bound technique for the same problem. Also, this paper is to solve large problem scale and provide it if the multiple machining routes are existed an optimal solution.

• 농촌지도와개발
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• 제25권4호
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• pp.175-184
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• 2018

There are two main types of agricultural extension projects in Korea, the impacts and routes of each type on farm income are different. This paper empirically studies the impact of agricultural extension to farms' income, using Multi-level production function considering time lag. It is found that direct type of extension has positive effect to farms' income. Also indirect type on income is significant only when the level of education is high. Due to the characteristics of Korean agricultural structure, the technical level of farm is greatly influenced by the government's R&D investment and technology guidance. The result implies that indirect type of extension that take into account the educational level of farms should be emphasized for long-term technological advances.