• Tunnel and Underground Space
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• v.20 no.3
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• pp.169-182
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• 2010

H-beam and lattice-girder are the two most commonly used steel supports in domestic tunnels. Reinforced Ribs of Shotcrete(R.R.S.), which is frequently used in Scandinavian countries, is yet to be employed in Korea despite its advantages over H-beam or lattice girder in terms of economy and constructional efficiency. In this study, laboratory tests were conducted to determine the most suitable design of R.R.S in domestic tunnels. Various configuration of steel reinforcements including double layer of steel rebars were tested and compared. Reinforcement with H-beam and lattice girder were also analyzed. Results of this study can be of great use in selecting and designing of tunnel supports when the tunnel is excavated by NATM or Norwegian Method of Tunnelling(NMT).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.837-844
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• 2014

Automotive manufacturers have recently developed various technologies for improving fuel economy and satisfying enhanced emission regulations. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of ignition. A conventional LPG engine has been redesigned to an ultra-lean-burn LPG direct injection engine in order to adopt combustion system of ultra-lean-burn. This study is aimed at investigating the effect of a change in the compression ratio on the performance and emission characteristics of a lean-burn LPG engine. The fuel consumption, heat release rate, combustion pressure, and emission characteristics are estimated depending on changing the effect of compression ratio. When the compression ratio is increased, it is difficult to improve the fuel consumption owing to an unstable combustion state, but the total hydrocarbon and nitrogen oxide emissions are reduced.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.693-698
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• 2017

The 18650 battery cell is known to be reliable and cost effective, but it has a design limitation and low electric capacity compared to pouch-type cells. Because its economy is superior, an 18650-cell-type battery pack is chosen. A reliable temperature is very important in automobile battery packs. Therefore, in this study, the temperature stability of the battery pack is predicted using CFD simulation. Following 3C discharge tests, the results for the heat generation of the battery cell are compared to the simulation results. Based on these results, a natural convection condition, forced convection condition, direct cell-cooling condition, cooling condition on the upper and lower surfaces of the battery pack, and cooling condition using air channels are all simulated. The results indicate that the efficiency and the performance of the air-channel-type cooling system is good.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.355-386
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• 2006

This paper analyses recent regional development policies being carried out in Japan and the U.S. Such policies are formed on the sustainability principle aiming at the realization of circula-flow economy and zero waste society. The study here illuminates Japan's Eco-town project and three cases of eco-industrial developments in Minnesota. Such projects have gone from improving industry competitiveness through constructing clean production systems on the company level to improving national competitiveness through constructing a 'circular society' on the government level. Japan included the realization of a 'circular society' as its government's top agenda because it recognized that environmental pollution stems from the inefficient use of natural resources. Eco-town project is a regional development policy specifically reflecting such recognition. The eco-efficiency based city development approaches in Minnesota are but small examples of the new wave in regional development in the developed countries. We need to go beyond emphasizing eco-friendly and ethical management to just the companies. The government itself needs to design national policies based on environmental sustainability.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.40-48
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• 2013

Recently, many types of electric vehicles including a heavy duty vehicle have been developed and released because of the better fuel economy and less gas products. In this study, research about an electric bus which utilizes the wheel motor drive system was conducted. The wheel motor is a motor connected to the wheel directly only with a simple gear so that the developer can utilize the space efficiently and the whole system efficiency will be better because of simple structure. However, because it is different from former types of vehicles which use the differential gear, the development of the integrated control logic is required in order to meet the vehicle stability and driving performance. The developed control logic is composed with direct yaw moment control, regenerative braking control and slip control logics. It is compared to the control logics which does not consist of direct yaw moment control and slip control when the vehicle is exposed in tough situations. For the unification of the control logic, a few maps were developed and applied to determine the output torque of each motor according to the driving status. As a result, it is shown that the developed control logic is more safe and well follow the target speed than the other control logic applied simulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.82-91
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• 2017

This paper is a study on the bi-directional DC-DC converter, one of the key elements of 48V-12V dual systems in mild hybrid electric vehicles. Mild hybrid electric vehicles require a bi-directional DC-DC converter that can efficiently transmit power in two directions between a 48V battery and a 12V battery. To develop a bi-directional DC-DC converter with better price competitiveness, upgraded fuel economy, excellent performance and smaller size, this study designed, produced and presented a circuit that improved on the existing one. In the proposed 8-phase bi-directional DC-DC converter, the size of the passive element was reduced through the 8-phase interleaved topology, whereas downscaling had previously posed a difficulty. This study also designed and produced a 2.5kW class prototype. Based on the proposed 8-phase interleaved topology, a size of 227.5 (W) * 172 (L) * 64.35 (H) was achieved. In the boost mode operation and buck operation modes, the maximum efficiency was recorded at 94.04 % and 95.78 %, respectively.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.119-141
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• 2020

The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.404-414
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• 2010

The primary purpose of this paper is to identify the influencing factors on the post acceptance behavior of user in internet banking. For this purpose, a research model and hypotheses are developed based on the relevant literature reviews. Data have been collected from 248 users who have used internet banking and the research hypotheses were tested by covariance structural model analysis. The results of this empirical study are summarized as follows. First, security, confirmation, and perceived ease of use have positive influence upon user's perceived usefulness. Second, security, economy efficiency, and confirmation have positive influence upon user's satisfaction. Third, loyalty incentives have positive influence upon continuance intention. Lastly, user's perceived usefulness have positive effect on the satisfaction, and user's perceived usefulness and satisfaction positively related to continuance intention in internet banking. The findings have significant implications for internet banking service providers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.377-379
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• 2018

In recent years, with the focus on the younger generation, a minimal life that pursues a simple and light life has attracted attention, and a product that occupies a small space and has high practicality attracts attention. Therefore, a lot of studies on small but realistic products are going on by combining plural products into one. In this study, we developed a smart stand that can save space on the desk. The stand is equipped with a smartphone holder, humidifier, negative ion generator, and speaker functions. Because of this study, it is expected that the efficiency of space and economy will be improved in a small house of one person.

• Journal of Arbitration Studies
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• v.18 no.3
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• pp.117-138
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• 2008

This study lies on building the International Standardization of China Arbitration System for improving a relationship of mutual trust and the safety trade between China and other worldwide countries, especially, South Korea as their one of the biggest trading partners through the comparative analysis of China and UNCITRAL Arbitration Law. In this analysis, the differences from China and UNCITRAL in arbitration law are like belows ; lack of arbitrator's international mind, the limitation of private property right, prohibition of Ad. hoc arbitration, arbitrator's biased nationalism, localism, and their short specialties. a deficiency of the objectiveness for arbitrator's election, a judgement rejection of claimants by using nonattendance and walkout, impossibility of prior and temporary property custody for execution of arbitration award. etc. For the improvement of the International Standardization of China Arbitration, this paper propose as follows: 1) Extension of private property right, reorganization of tax system, realization of open competition, exclusion of 'Sinocentrism', globalization of arbitration system 2) The abolition of old fashioned bureaucracy with approval for ad.hoc arbitration 3) An education for arbitrator's internationalization, specialty, and to promote legal knowledge 4) A settlement of the third country arbitrators' selection for reflecting interested party's decision by the court in a selection system of arbitration committee. 5) Institutionalization of arbitration judgment that prevent for claimant's avoidance by using a withdrawal and an intentional absent 6) A permission of the right of claimant's court custody directly before the begging of arbitration request for the prevention for destruction of evidence and property concealment 7) Grant of the arbitration tribunal's interim measures of protection for private property preservation to the third party, proof security, prevention from the loss that selling the corruptible goods 8) Improvement of arbitration's efficiency from the exclusion of the obstacles that are forgery, concealed evidence, and arbitrator's bribe taking Lastly, I hope that this study will serve to promote friendly economic relationship between China and South Korea and strive for international equilibrium through the achievement of China Arbitration's International Standardization. I will finish this paper with a firm belief that this will lead to more advanced studies.