• Journal of the Korean Magnetic Resonance Society
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• v.21 no.4
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• pp.126-130
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• 2017

In the developed NMR hyperpolarization techniques, Parahydrogen-Induced Polarization (PHIP) technique is widely utilized to overcome the low sensitivity of the NMR/MRI. Parahydrogen generator is essential to produce high spin order of parahydrogen molecule. Commercial parahydrogen generator is well developed with user-friendly systems. However, it has drawbacks of long preparation time (~ 2h including cooling down time of 1h) and high cost (~ 200 million won) for the commercial setup. We designed a simple and portable parahydrogen generating system with low cost (~ 2 million won), which produce polarization in less than 1 min. With the designed parahydrogen generator, we successfully performed the PHIP with Wilkinson's catalyst on styrene. This study will broaden the parahydrogen based polarization transfer study on many researchers by providing the simple portable and low cost parahydrogen generator.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.263-277
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• 2005

In this paper, we introduce algorithms for constructing broadcasting and multicasting trees. These algorithms are general because they may be used for tree cost functions that are of arbitrary form. Thus, essentially the same algorithmic procedures are used for different tree cost functions. We evaluate the effectiveness of the general algorithms by applying them to different cost functions that are often used to model wired and wireless net­works. Besides providing a unifying framework for dealing with many present and future tree-construction applications, these algorithms typically outperform some existing algorithms that are specifically designed for energy-aware wireless networks. These general algorithms perform well at the expense of higher computational complexity. They are centralized algorithms, requiring the full network information for tree construction. Thus, we also present variations of these general algorithms to yield other algorithms that have lower complexity and distributed implementation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1073-1080
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• 1999

Optimal routing of distribution networks can be attained by keeping the line power capacity limit to handle load requirements, acceptable voltage at customer loads, and the reliability indices such as SAIFI, SAIDI, CAIDI, and ASAI limits. This method is composed of optimal loss reduction and optimal reliability cost reduction. The former is solved relating to the conductor resistance of all alternative routes, and the latter is solved relating to the failure rate and duration of each alternative route. The routing considering optimal loss only and both optimal loss and optimal reliability cost are compared in this paper. The case studies with 10 and 24 bus distribution networks showed that reliability cost should be considered as well as loss reduction to achieve the optimal routing in the distribution networks.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2537-2539
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• 1999

In order to widen the radius of electric vehicle (EV) travel recharging points must be provided in sufficient numbers and at convenient places. The cost of providing side an infrastructure is at preset, not well documented and this lack of information acts as a detersent to prospective insestors in EV technology. This paper acts as a preliminancy investigation into the cost of infrastructure is the different situation i.e for the private owner, the fleet owner or for the public. It provides an overview of the items required and this relative costs. Cost will however, vary from country to country and application to application, and this paper two acts purely as guide to the type of equipment and its relative costs.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.750-755
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• 2014

Product shortage which causes backordering and/or lost sales cost is very popular in chemical industries, especially in commodity polymer business. This study deals with backordering cost in the supply chain optimization model under the framework of process-inventory network. Classical economic order quantity model with backordering cost suggested optimal time delay and lot size of the final product delivery. Backordering can be compensated by advancing production/transportation of it or purchasing substitute product from third party as well as product delivery delay in supply chain network. Optimal solutions considering all means to recover shortage are more complicated than the classical one. We found three different solutions depending on parametric range and variable bounds. Optimal capacity of production/transportation processes associated with the product in backordering can be different from that when the product is not in backordering. The product shipping cycle time computed in this study was smaller than that optimized by the classical EOQ model.

• Asia pacific journal of information systems
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• v.13 no.2
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• pp.67-85
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• 2003

This study was conducted to analyze Korean companie's perception in IT investment cost-benefit analysis(CBA), and to see if various user group's perception is different. Literature was reviewed to classify and define variables in IT CBA, and questionnaire was distributed to CEOs, CIOs, IT managers, and general managers in Korean companies. Respondent's priority ranking in IT CBA was shown to be tangible benefit, direct cost/intangible benefit, and indirect cost/risk. Data analysis showed that Korean companie's actual practice in CBA was generally aligned with their perception. User group's(Executives vs. mangers, and IT managers vs. general managers) perception was not shown to be statistically different. Survey result also showed that IT CBA was not well practiced in the companies although respondents perceive the analysis very important. These findings suggest that more education and practical experience is needed for Korean companies to perform IT CBA.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1542-1548
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• 2010

Transportation cost takes a major portion on logistics cost. The reduction of transportation cost is a key issue to achieve national competitiveness and logistics cost reduction. And railway must play a important role to shift from road freight transport to environment-friendly transport. There are many idle freight cars in railway freight transportation and they give rise to inefficient operation of freight car. It is well known that the main reason of idle freight cars is unbalanced demand according to direction. In this study, we analysed the current status on idle freight cars in railway at the level of daily data. This results help follow-up research to cut down idle freight cars in railway.

• Archives of Plastic Surgery
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• v.41 no.3
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• pp.213-217
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• 2014

The widespread use of microsurgery in numerous surgical fields has increased the need for basic microsurgical training outside of the operating room. The traditional start of microsurgical training has been in undertaking a 5-day basic microsurgery course. In an era characterised by financial constraints in academic and healthcare institutions as well as increasing emphasis on patient safety, there has been a shift in microsurgery training to simulation environments. This paper reviews the stepwise framework of microsurgical skill acquisition providing a cost analysis of basic microsurgery courses in order to aid planning and dissemination of microsurgical training worldwide.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.1
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• pp.37-50
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• 1996

This paper presents an EMQ model which determines an economic manufacturing quantity in an unreliable machine. It is assumed that life time of a machine is generally distributed and it requires an instantaneous repair time when a machine fails. Depending on various types of failure rate function of a machine, it is discussed how to determine an EMQ and prove its uniqueness. Variations of an EMQ depending on repair cost are also examined. Through numerical experiments, extensive investigations are carried out on the effects of repair cost and setup cost to an EMQ as well as average cost, and some interesting behaviors are observed.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.493-501
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• 2001

B2C is not doing well in Asia and Pacific countries in comparison to U.S. and Europe. But there is misunderstanding of low growth of B2C electric commerce caused by cultural factor. Consumers in market are rational to decide their purchase according to total cost - market price and transaction cost. I examined this with data of Korea and U.S. Transaction cost in real market is less in Korea than in U.S. but that of electric commerce, it is much less in U.S. As a result, the choice of consumers in Korea is real market transaction while consumers in U.S. choose electric commerce.