• Journal of Environmental Policy
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• v.9 no.2
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• pp.41-55
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• 2010

This paper analyzes optimal watershed management focusing on reservoir-level sediment removal techniques. Although dams and reservoirs provide several benefits, sedimentation may reduce their storage capacity. As of today, the Aswan High Dam (AHD) in Egypt faces approximately 76% reduced life of the reservoir. Since the AHD is the major fresh water source in Egypt, sustainable use of this resource is extremely important. A model is developed to simultaneously determine optimal sediment removal strategies for upstream soil conservation efforts and reservoir-level sediment control. Two sediment removal techniques are considered: mechanical dredging and hydro-suction sediment removal system (HSRS). Moreover, different levels of upstream soil conservation efforts have introduced to control soil erosion, which is a major contributor of reservoir storage capacity reduction. We compare a baseline case, which implies no management alternative, to non-cooperative and social planners' solution. Our empirical results indicate that the socially optimal sediment removal technique is a mechanical dredging with unconstrained amount with providing a sustainable life of the reservoir. From the empirical results, we find that social welfare can be as high as $151.01 billion, and is sensitive to interest rates and agricultural soil loss.

• Journal of Environmental Science International
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• v.14 no.12
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• pp.1141-1153
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• 2005

Butyltin compounds (BTs), namely tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT), were measured in surface and core sediments collected in 2001 inside Seogwipo Harbor, in order to evaluate their distribution characteristics. Seogwipo Harbor is one of major harbors of Jeju Island where a lot of shipping occurs and is designated as a trade port by the Korea Maritime and Port Law. BTs were detected in surface and core sediments of all stations and their concentrations in surface sediments were low, compared with to those in other sites of domestic and foreign countries. The main species among BTs was MBT, although there was a little difference with a survey site in surface sediments and in core sediments with depth. No or low correlations were obtained between organic matter or particles size of surface and core sediments and total BTs, indicating that these factors did not affect the distribution of BTs. It was estimated that more complex factors including BTs loads and surrounding sedimentary environments, affect the distribution of BTs. The high correlations between BTs indicated that DBT and MBT were mainly degraded from TBT based on antifouling paints of vessel etc. and other sources, such as DBT and MBT, could be ignored. The butyltin degradation indices ([DBT]+[MBT]/[TBT]) in surface sediments were in the range of $2.0\~3.8$ (mean 3.0), indicating that the parent compound, TBT, were inflowed into the surface sediments a long years ago, degraded and deposited. The sedimentation age of BTs contaminated core sediments could not estimated because the content of $^{210}pb$ activity were nearly all the same and so the sedimentation rate could not obtained.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.33-40
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• 2011

The World exposition is considered as a great event to promote the cultural exchanges of their own urbanism and share the technological developments among the various countries across the all over the world. So many countries in the world desired to host and take part in the EXPO, so far only few countries have had the chance to hold the event and show their uniqueness of urban culture, but we might say the past exhibition as those for display and publication of matters of science, technology and trade, now we must say expositions of the 21th century has come under variations on cultural and informational interchange and humanism from the global issue and problem. What makes possible to maximize the effort of reciprocal communication between people and the public can be the EXPO event as a means of the public information of the theme and this kind of event should suggest the public a message of the topic, message, image and even more the EXPO spirits and theme as an international event gives as much considerably spreading effect as its big scale. In that aspect, the pavilion for the exhibition of EXPO and public information should be recognized as a place for smoothly forming the activities of reciprocal communication between the society and the public, with such a aspect this study, as its purpose of improving as well as communication, concerns the process in projecting the space paradigm of pavilion in the EXPO and public message and information as a means of the communication of the global theme.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.530-539
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• 2013

In large vessels, proper water level must be maintained with a balance for right and left equilibrium by absorbing or draining sea water in ballast water tank. However, this ship's ballast-water can be drained marine organisms to local sea area by world trade and this can be a source of ecological disturb. In order to solve these problems, marine organisms must be removed in accordance with the international covenant for the emission of microorganisms. By this reason, the seawater electrolysis rectifier of low-voltage high-current rectifiers with excellent ability for microbial treatment is required. In this paper, PSFB converter will be discussed for the seawater electrolysis rectifier. Furthermore, a new output control method with the power limit operation under the limited maximum voltage condition is proposed for this rectifier. The simulation for the proposed current control method for PSFB Converter is shown using MATLAB/SIMULINK. Finally the usefulness of the proposed control method is presented by the experimental results.

• Journal of Korean Society for Quality Management
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• v.45 no.1
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• pp.129-138
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• 2017

Purpose: This research aims to analyze the service process of corporate courier services in order to offer service providers possible directions for adaptation of new technologies and assurance of better quality services. Methods: Through the analysis on the parcel service process of company Y by applying service blueprinting method, the overall process and failure service points of corporate courier services can be recognized and investigated. Next, the several newer technologies, augmented reality glasses, exoskeleton, and drone are applied to the service process of company Y as they are suggested by the literature review and referenced to DHL's report on the Fourth Industrial Revolution. Then, service options to overcome the service failure points to improve the service process can be produced. Results: The parcel service process of the company Y is utilized as a hub-and-spoke structure by having distribution and delivery centers which separates customers into two types, ones using the total services and the others only using the delivery service. In addition, the main cause of the service failures is determined that it is due to the limited working hours of delivery centers compared to the workload. Conclusion: This research contributes in better understanding of corporate courier services and providing information for benchmarking. An empirical research on the costs and the efficiencies of applying the new technologies is suggested for the further improvement in the processes of corporate courier services.

• Journal of Plant Biotechnology
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• v.7 no.2
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• pp.81-86
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• 2005

Panax ginseng is one of the most important medicinal plants in the world. The international trade of ginseng is increasing yearly. The disguise of Chinese and American ginseng into Korean ginseng became a problem in recent years in abroad and Korea. An effective method to authenticate the Korean Panax ginseng from others at a DNA level is necessary for the healthy development of the ginseng market. Amplified fragment length polymorphism (AFLP) analysis was applied to develop a method for the identification of Korean ginseng between Chinese ginseng and American ginseng. It is very difficult to detect the different polymorphic bands among Korean field cultivated ginseng, and between field and wild-cultivated ginseng. The genetic distance coefficient by AFLP analysis between field- and wild cultivated Korean ginseng was very low, 0.056. Whereas, polymorphic bands between Korean and Chinese wild-cultivated ginseng was significantly different. The genetic distance coefficient between wild-cultivated Korean and Chinese ginseng was 0.149. The genetic distance coefficients between the P. ginseng and P. quinquefolius were ranging from 0.626 to 0.666. These results support that the AFLP analysis could be applied to authenticate Korean P. ginseng from others Chinese P. ginseng and American ginseng (P. quinquefolius).

• Economic and Environmental Geology
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• v.42 no.6
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• pp.645-654
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• 2009

Recently there have been increasing consumers' interests in the geographical origin of foods, due to the FTA (Free Trade Agreement) in the global market. Especially, in Korea, in relation to BSE (bovine spongiform encephalopathy), it is considered to be urgent to develop analytical techniques for distinguishing the geographical origin of beef. Korea is facing conclusion of FTA with many countries, and there is a deep national concern about the distinction of the geographical origin of food. Diverse analytical techniques have been used in many of recent researches to obtain data for distinguishing the geographical origin of foods produced in various countries. In this paper, we reviewed national and international researches about tracing of geographical origin and food authentication using stable isotopes. Improvement of the isotopic techniques and their numerous application have been provided useful information of their geographical origin in food products. Furthermore, we expect that this study could be detecting of many frauds and illegal transaction of food products. We look forward to active progressing research of detecting food origin using isotope analysis and numerous application about imported food products.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.761-769
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• 2007

The configuration of the flow channel on a bipolar plate of a proton exchange membrane fuel cell(PEMFC) for efficient reactant supply has great influence on the performance of the fuel cell. Recent demand for higher energy density fuel cells requires an increase in current density at mid voltage range and a decrease in concentration overvoltage at high current density. Therefore, an interdigitated flow channel where mass transfer rate by convection through a gas diffusion layer is greater than the mass transfer by a diffusion mechanism through a gas diffusion layer was recently proposed. This study attempts to analyze the i-V performance, mass transfer and pressure drop in interdigitated flow channels by developing a fully three dimensional simulation model for PEMFC that can deal with anode and cathode flow together. The results indicate that the trade off between performance and pressure loss should be considered for efficient design of flow channels. Although the performance of the fuel cell with interdigitated flow is better than that with conventional flow channels due to a strong mass transfer rate by convection across a gas diffusion layer, there is also an increase in friction due to the strong convection through the porous diffusion layer accompanied by a larger pressure drop along the flow channel. It was evident that the proper selection of the ratio of channel and rib width under counter flow conditions in the fuel cell with interdigitated flow are necessary to optimize the interdigitated flow field design.

• Korean Institute of Interior Design Journal
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• v.18 no.2
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• pp.50-60
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• 2009

The change of idea about overall politics, society, technology, and culture in 20th century led to the change of kitchen which is the central space of household affairs as well. Frankfurt kitchen of Margarete Schuette Lihotzky which was introduced for the first time at Germany International Trade Exhibition in 1927 functionally designed small space of $6.5m^2$ with considering move-line and convenience. This is the beginning of kitchen type which has built-in sink and cupboard that is regarded as an universal option these days, and this has extensively been applied to kitchen system throughout the world after the repetitive development in America, Sweden and Switzerland. And improved kitchen of Park Gil-Yong which was influenced by rationalism introduced from the house improvement campaign and the opening of a port which were progressed in Korea in $1919{\sim}1930$ is the first stand-up kitchen which improved the inefficiency of Korean conventional kitchen. The purpose of this study is to understand the change aspect of kitchen through the rationalization in each country by comparing the introduction background of the times, change of space for residence and kitchen, and the characteristics of kitchen plan which had influence at the turning point on the kitchen in Korea, Europe on the side of efficiency at the same period, take into consideration of our residing-culture which has rapidly been changed between tradition and modernity, and to see the direction of kitchen design which copes with the unique residential environment.

• Environmental and Resource Economics Review
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• v.23 no.3
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• pp.453-472
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• 2014

Analyzing the effects of carbon emissions trading, which is scheduled to be introduced in Korea in 2015, requires an accurate assessment of $CO_2$ abatement costs by both industries and firms. Firms faced with regulatory constraints are unlikely to minimize their production costs due to rising production costs caused by allocative inefficiency of inputs. The use of a distance function would results in underestimation of $CO_2$ abatement costs, because it fails to capture the allocative distortion costs. Recognizing the disadvantage of the previous approach, first, this paper tests for allocative efficiency of input for the Korean steel industry over the period 1990-2010, then derives the marginal $CO_2$ abatement costs by applying a cost function approach. The hypothesis of allocative efficiency in inputs is rejected and the steel industry pays an annual average cost of 92,000 won in removing an additional ton of $CO_2$ over the sample period.