• Economic and Environmental Geology
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• v.42 no.3
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• pp.235-246
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• 2009

High-saline ground water, whose eclectrical conductivity value ranges from 12,000 to 21,000 $\mu$S/cm, occurs at the small catchment of Gilsan stream near Geum-river estuary dike. These high-saline ground water comes form three different aquifers consisting of two horizons of sand sediments and one weathered zone with top part of unconformity. For these three aquifers showing mutual independence in terms of hydrogeological and hydrogeochemical connection, we examined characteristics of aqifer occurrences and their water chemistry, and observed and analyzed the fluctuations of the ground water level and electrical conductivity. Our study results indicate that the high-saline characteristics of ground water in this study area should not come from dynamic recent seawater intrusion, but might be due to the fossil saline water included and isolated within the paleo-sediments or weathered zone and their upper unconformity part. This high-saline water seems to be now partially mixed and affected by freshwater in the higher inland reach of Gilsan stream.

• Korean System Dynamics Review
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• v.2 no.2
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• pp.25-40
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• 2001

This paper describes the forecast of power plant construction in a competitive korean electricity market. In Korea, KEPCO (Korea Electric Power Corporation, fully controlled by government) was responsible for from the production of the electricity to the sale of electricity to customer. However, the generation part is separated from KEPCO and six generation companies were established for whole sale competition from April 1st, 2001. The generation companies consist of five fossil power companies and one nuclear power company in Korea at present time. Fossil power companies are scheduled to be sold to private companies including foreign investors. Nuclear power company is owned and controlled by government. The competition in generation market will start from 2003. ISO (Independence System Operator will purchase the electricity from the power exchange market. The market price is determined by the SMP(System Marginal Price) which is decided by the balance between demand and supply of electricity in power exchange market. Under this uncertain circumstance, the energy policy planners such as government are interested to the construction of the power plant in the future. These interests are accelerated due to the recent shortage of electricity supply in California. In the competitive market, investors are no longer interested in the investment for the capital intensive, long lead time generating technologies such as nuclear and coal plants. Large unclear and coal plants were no longer the top choices. Instead, investors in the competitive market are interested in smaller, more efficient, cheaper, cleaner technologies such as CCGT(Combined Cycle Gas Turbine). Electricity is treated as commodity in the competitive market. The investors behavior in the commodity market shows that the new investment decision is made when the market price exceeds the sum of capital cost and variable cost of the new facility and the existing facility utilization depends on the marginal cost of the facility. This investors behavior can be applied to the new investments for the power plant. Under these postulations, there is the potential for power plant construction to appear in waves causing alternating periods of over and under supply of electricity like commodity production or real estate production. A computer model was developed to sturdy the possibility that construction will appear in waves of boom and bust in Korean electricity market. This model was constructed using System Dynamics method pioneered by Forrester(MIT, 1961) and explained in recent text by Sternman (Business Dynamics, MIT, 2000) and the recent work by Andrew Ford(Energy Policy, 1999). This model was designed based on the Energy Policy results(Ford, 1999) with parameters for loads and resources in Korea. This Korea Market Model was developed and tested in a small scale project to demonstrate the usefulness of the System Dynamics approach. Korea electricity market is isolated and not allowed to import electricity from outsides. In this model, the base load such as unclear and large coal power plant are assumed to be user specified investment and only CCGT is selected for new investment by investors in the market. This model may be used to learn if government investment in new unclear plants could compensate for the unstable actions of private developers. This model can be used to test the policy focused on the role of unclear investments over time. This model also can be used to test whether the future power plant construction can meet the government targets for the mix of generating resources and to test whether to maintain stable price in the spot market.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.18
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• pp.105-134
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• 2002

In the Spring of 2000, the Banking Commission of the ICC decided to appoint a working group to draft a supplement to the UCP 500 to clarify the position regarding electronic presentation under a documentary credit. Provisions was drafted to supplement its existing rules for documentary credit, that is, UCP 500. These new provisions known as Supplement to UCP 500 for Electronic Presentation was approved by the ICC Banking Commission at the beginning of November 2001 and came in force as of 1 April 2002 The eUCP covers matters such as definitions of key terms such as electronic record, electronic signature, format, paper document, received. An eUCP Credit must specify the formats in which electronic records are to be presented and if not, electronic records may be presented in any format. Electronic records may be presented separately and need not be presented at the same time. The purpose of this paper is to understand the main substance of eUCP and to facilitate the introduction of electronic letter of credit by studying the problems and revision of eUCP and new electronic UCP. The main substances of eUCP are electronic address as place for presentation of electronic records, flexibility of the formats of electronic records to be presented, endowment of the notice of completeness of presentation to the beneficiary, one electronic record satisfying one or more originals or copies of an electronic record, the electronic records to be examined including the electronic record at the hyperlink to an external system or the referenced system, no remark as to the time period for the examination of documents. The Roles of eUCP are the Promotion of the Electronic Trade, the Supply of Basis on the Uniform Rules for Electronic Letter of Credit, the introduction of Electronic Trade Model. The characteristics of eUCP are a supplement to the UCP, no address of any issues relating to the issuance or advice of Credit electronically, independence of specific technologies and developing electronic commerce system, that is, Bolero Service. The Problems of eUCP are flexibility of format of electronic record, heavy burden on the side of banks, and the problems regrading the number of presentation, the notice of completeness of presentation, no provision in regard to the time to examine the electronic records, and representation of the electronic records. In the revision of eUCP to resolve the problems, the things to be taken into consideration are as follows; the designation of the format allowing the banks to examine electronically, prohibition of the paper documents, the development of the system receiving the electronic records, the addition of the reception notice on the side of the banks, the setting of the time to examine the electronic records, the construction of the backup system or the dual processing system.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.1
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• pp.61-70
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• 2012

Feasibility of co-digestion was investigated by a series of anaerobic batch experiments using sewage sludge, swine waste, and food waste leachate as substrates. The organic solid wastes were collected from M city, where the daily productions of sewage sludge, swine waste, and food waste leachate were 178 ton/d, 150 ton/d, and 8 ton/d, respectively. Both swine waste and food waste leachate showed superior methane yields, methane productivities, and organic pollutant removal efficiencies compared to sewage sludge. Co-digestion of the total amounts of organic solid wastes would enhance methane production by 5.60 times $(530\;m^{3}\;CH_{4}/d\;{\rightarrow}\;2,968\;m^{3}\;CH_{4}/d)$. However, it also increase the amount of digestate by 1.88 times with 3.79 to 4.92 times higher pollutants (chemical oxygen demands total nitrogen, and total phosphorus) loading rates. Co-digestion of organic solid wastes is a valid strategy to enhance the performance of an anaerobic sludge digester and the energy independence of a wastewater treatment plant. Anyhow,the increment of digestate with higher pollutant loading would need a careful counterplan in the operation of the main stream of the treatment plant.

• Journal of Science Education
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• v.40 no.1
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• pp.31-51
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• 2016

The purpose of this study was to develop "Movie Production Project" Science-Arts convergence STEAM program for elementary students and investigate the effects of the program on career orientation of science, career awareness and creative personality. Participants were 82 elementary school students. The results of this study were as follows: First, experimental group's total score of career orientation of science was significantly higher than that of comparative group. Among sub-areas, science learning preference, science career preference and perception on science career worth were significantly different between two groups. Experimental group's scores were significantly higher than those of comparative group. Second, experimental group's career awareness total score was significantly higher than that of comparative group including all sub-areas. Third, experimental group's creative personality total score was significantly higher than that of comparative group including 2 sub-areas, independence, openness. Finally, experimental group student's perception on the program showed that it was interesting, a little easy and they hoped to study again.

• The Korean Journal of Applied Statistics
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• v.33 no.3
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• pp.335-345
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• 2020

This paper deals with the problem of estimating the log-transformed linear regression model to fit actual battle data from the Ardennes Campaign of World War II into the Lanchester model. The problem of determining a global solution for parameters and multicollinearity problems are identified and modified by examining the results of previous studies on data. The least squares method requires attention because a local solution can be found rather than a global solution if considering a specific constraint or a limited candidate group. The method of exploring this multicollinearity problem can be confirmed by a statistic known as a variance inflation factor. Therefore, the Lanchester model is simplified to avoid these problems, and the combat power attrition rate model was proposed which is statistically significant and easy to explain. When fitting the model, the dependence problem between the data has occurred due to autocorrelation. Matters that might be underestimated or overestimated were resolved by the Cochrane-Orcutt method as well as guaranteeing independence and normality.

• Journal of Korean Society of Transportation
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• v.25 no.1 s.94
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• pp.109-119
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• 2007

Increasingly, the emphasis in regional Passenger rail Planning is finding ways to more efficiently use existing facilities, with particular attention being Paid to Policies designed to spread Peak-Period travel demand more evenly throughout the week with consideration of train classification. In this context the individual's choice of time to travel is of crucial significance. This paper investigates the use of multinomial logit analysis to model ridership by rail classification using data collected for travel from Seoul to Busan during the one week in October 2004. The Particular model form that was successfully calibrated was the multinomial logit (MNL) model : it describes the choice mechanism that will Permit rail systems and operations to be planned on a more reliable basis. The assumption of independently and identically distributed(IID) error terms in the MNL model leads to its infamous independence from irrelevant alternatives (IIA) property. Relaxation of the IID assumption has been undertaken along a number or isolated dimensions leading to the development of the MNL model. For business and related rail travel patterns, the most important variables of choice were time and frequency to the chosen destination. The calibrated model showed high agreement between observed and Predicted market shares. The model is expected to be of use to railroad authorities in Planning and determining business strategies in the Increasingly competitive environment or regional rail transport.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.29-47
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• 2007

Owing to the rapid growth of using the Internet, not only click-and-mortar companies but also brick-and-mortar ones have been expanding their distribution channels into online, Moreover, since online channels are more attractive than offline ones in control and maintenance, switching customers into online ones is emerged as one of very important managerial issues in a view of reduction of cost as well as expansion of services. However, the switched customers should be faced by uncertainties which could not have been experienced in offline. Specifically, in online channels, buyers and sellers are separated temporally and spacially and there are always so many kinds of threat for security as well as not enough systems and conventions for them yet. Therefore, trust has been considered as one of the most critical mechanisms for resolution of such uncertainties in online transactions. However, it is not easy to build and maintain the relationships in online since most of them are virtual and indirect generally. Therefore, in order to switch offline customers into online ones, it is very important to make strategies based on identification of the relationship between online transaction and offline trust which has been built in offline business. Generally offline trust, which has been built independent of online, could not include trust for online-dependent activities such as payment security during or after transactions, while most of online trust include it. Therefore, a customer with high offline trust does not always perceive high security and assure safe transactions. Accordingly, while online trust, where technical capabilities for online security is one of main bases, includes control trust implicitly or explicitly, offline trust does not. However. in spite of such clear discrimination and independence between offline trust and perceived security, there can be the significant dependency between these two beliefs. The customers with high offline trust believe that the company would do some activities for online security for customers' safe transactions since it has been believed of doing well for customers' trust. Theoretically, users' perception of security is interpreted as a kind of control trus, which is trust for company's technical control capacities in order to resolve technical uncertainties in online. Therefore, the relationship between two beliefs can be considered as transference from offline trust to another type trust. that is, control trust. The objective of this study is to analyze the effect of offline trust on online transaction uses mediated by perceived security. For this purpose, we suggest a research model based on technology acceptance model (TAM). Reuse intention is adopted as a dependent variable and TAM is modified by adding perceived risk (PR) as well as two beliefs of using Internet banking, perceived usefulness (PU) and perceived ease of use (PEOU). Moreover, perceive security (PS) is adopted as an external variable for PR and PU, while offline trust (OT) is an antecedent of PS. For an empirical test, sampling from 108 visitors to the banks in Daegu, Korea, we analyze our model by partial least square (PLS) approach. In result, our model is shown to explain 51.4% of the variance in reuse intention and all hypothesis are supported statistically. A theoretical implication of this study is to identify a role of PS between offline trust and reuse intention of using online transaction services. According to our result, PS can be considered as a mediation variable for bridging between two different concepts: trust that explains social aspects of customers and companies, and TAM that explains customers' reuse intention.

• Therapeutic Science for Rehabilitation
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• v.2 no.1
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• pp.36-47
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• 2013

Objective : To identify the effect of bilateral arm training for activities of daily living(ADL) of the chronic phase after stroke. Methods : 20 patients with stroke, randomized to an experimental group(n=10) and a control group(n=10). Both groups received the usual occupational therapy. In addition, an experimental group received an bilateral arm training, 30-min sessions per a day for 6 weeks. The Functional Independence Measure(FIM) was used to evaluate ADL for both groups. Results : First, there is a significant difference before and after receiving the bilateral arm training(p <.05). Second, there are significant differences in all ADL areas of Self-care, Transfer, Social cognition after bilateral arm training(p<.05). Third, there are significant differences in all sub-areas of Self-care, only stairs of Locomotion, and only Problem solving of Social cognition by comparing sub-areas as bilateral arm activity(before and after) and occupational therapy intervention(before and after). Conclusion : Using bilateral arm training for the chronic phase after stroke improved their abilities of ADL. Therefore, there are an expectation to use bilateral activity training for the chronic after stroke clinically and a need of further study about bilateral arm training related to ADL in the future.

• School Mathematics
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• v.10 no.2
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• pp.223-257
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• 2008

To understand terms and symbols correctly which is the basic factor of teaming mathematics is important for understanding and utilizing related mathematic contents. Since the definition of terms and symbols is the important starting point of learning mathematics, it has been studied a lot since the ancient times. This study investigates the transition of terms and symbols which was presented in our curriculum after Korea's independence and it also investigates terms and symbols which are used for the current middle school text books. As a result of studying the transition of the terms, more detailed and broader analysis should be done for the explanation, modification, deletion, and creation of the terms. And complements are needed for some of the terms and symbols. Also, some definition of the terms which are used in some of the current middle school text books should be explained in a way that is suitable for the students' capability. And some errors and omissions of the terms need to be corrected. Furthermore, we need to compare our definition of terms with that of the other countries and modify them if it is necessary. Also, It is better to put guidelines about the interpretation of terms and symbols in the curriculum to reduce the confusion which can be produced by the variety of explanation of the definition of terms and symbols.