• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.78-91
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• 2002

In the thermal power plant, there are six manipulated variables: main steam flow, feedwater flow, fuel flow, air flow, spray flow, and gas recirculation flow. There are five controlled variables: generator output, main steam pressure, main steam temperature, exhaust gas density, and reheater steam temperature. Therefore, the thermal power plant control system is a multinput and output system. In the control system, the main steam temperature is typically regulated by the fuel flow rate and the spray flow rate, and the reheater steam temperature is regulated by the gas recirculation flow rate. However, strict control of the steam temperature must be maintained to avoid thermal stress. Maintaining the steam temperature can be difficult due to heating value variation to the fuel source, time delay changes in the main steam temperature versus changes in fuel flow rate, difficulty of control of the main steam temperature control and the reheater steam temperature control system owing to the dynamic response characteristics of changes in steam temperature and the reheater steam temperature, and the fluctuation of inner fluid water and steam flow rates during the load-following operation. Up to the present time, the Proportional-Integral-Derivative Controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper focuses on the characteristic comparison of the PID controller and the modified 2-DOF PID Controller (Two-Degrees-Freedom Proportional-Integral-Derivative) on the DCS (Distributed Control System). The method is to design an optimal controller that can be operated on the thermal generating plant in Seoul, Korea. The modified 2-DOF PID controller is designed to enable parameters to fit into the thermal plant during disturbances. To attain an optimal control method, transfer function and operating data from start-up, running, and stop procedures of the thermal plant have been acquired. Through this research, the stable range of a 2-DOF parameter for only this system could be found for the start-up procedure and this parameter could be used for the tuning problem. Also, this paper addressed whether an intelligent tuning method based on immune network algorithms can be used effectively in tuning these controllers.

• Korean Business Review
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• v.17 no.2
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• pp.1-23
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• 2004

Since revision of Korean GAAP on the merge transaction in 1999, the few studies on the problems of the GAAP or on the inconsistency of GAAP and regarding tax regulations have been performed. The objective of this study is to understand the present state of the merge transactions, to find out the problems on the regarding GAAP and tax regulations, and to suggest the method to improve them. Among the 69 merge transactions of the listed and registered companies for the recent 3 years, 67 merge transactions are reported as the purchase transactions and 2 transactions as the pooling of interest. And 11 transactions occurred between parents and subsidiaries. I investigate the sufficiency of the foot disclosures on the merge transactions, I find out that the disclosure on the amortization of the negative goodwill are not sufficient, and several transactions are not recorded in conformity with GAAP. This paper indicates the problems on the GAAP as follows: the complicated and irrational method of amortization of the negative goodwill, the valuation of the stocks acquired before the merge, the inconsistent adjustments to purchase consideration contingent on future events, and the valuation of the merge between the parents and subsidiaries. And the problems on the tax regulations are as follows: tax deferment of the income from merge valuation, the ambiguous definitions of the fair value, and stock dividend of the income from merge valuation.

• Archives of design research
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• v.17 no.3
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• pp.81-90
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• 2004

The reason of the appearance of Internet is regarded as a milestone since we have shared information globally in a mutual way. The important thing on this point is what contents we choose for ourselves. The Internet could be meaningless unless we use it in a certain way, which ultimately means that the Internet has to deliver something valuable to us humans. Therefore, we have looked at how we can deliver and share humanity and emotion through the Internet, also how we can instill vital power into our real life, through the Internet. Fortunately, the current study must essentially be ongoing due to its nature with perhaps a multidisciplinary team brainstorming ideas. The reason for that is that not only could we find new business models for companies, but also find out new ways to appease the human mind in the modern age. In addition, as consumers needs become more specialized and diversified, companies are expected to face up to fierce competition with the help of innovative ideas. The ever-intensifying competition requires companies to cultivate new strategic tools in order to have new, powerful and sustainable comparative advantages. The goal of this research will be to explore ways of finding a new approach. Specifically, this research is about how to use the EVC(empathetic virtual character), which, this researcher believes, can deliver emotional benefits so as to make e-branding successful. According to reports, it has been proven that this new concept including the EVC can result in tremendous success. So the goal of this research is to explore the current situation and to anticipate the future concerning virtual characters.

• Archives of design research
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• v.17 no.3
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• pp.283-292
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• 2004

Today's fast-paced world is becoming increasingly characterized by technology-facilitated transactions. Growing numbers of customers interact with technology to create service outcomes instead of interacting with a service firm employee. Self-service technologies provide technological interfaces that enable customers to produce a service independent of direct service employee involvement. To investigate on the customer satisfaction with self-technological based product design in Subway. I used the critical incident technique developed by Flanagan(1954) with quantitative measures of attributions. In this research, it results that customers are considered more important the value of technological-function and easy to use than the aspect of automated machine. It is likely that the technological aspect of many self-service options has a unique influence on customer perceptions of self-service encounters. Also, Research has shown that customer's needs are defined as situations in which external environmental factors add a sense of urgency to the transaction and saved time. On the other hand, customers realize that their favorable image of self-technological based product follows as ; first, customers prefer to the simple & modern image on the aspect of product design, secondly, customers prefer to the hitech-functional image to do its job fast in a short time by automated technology on the aspect of functional service, thirdly, customers prefer to the comfortable and sanitary image to be suitable for the underground circumstance.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.133-153
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• 2020

Officially assessed land price has been the index of South Korea since 1989 throughout different sectors of tax and welfare. Officially assessed land price is used as a tax valuation for the tax on property holdings, and the equity of such is the most important factor in the fair taxation for the people of South Korea. On this wise, this research analyzed and verified the horizontal and vertical inequity of officially assessed land price in Seoul by using the real transaction data between 2016 and 2018. In fact, Seoul's assessment ratio for the entire three-year period was 60.64% and it showed to increase each year. Horizontal equity was found to be most favorable in 2017, and the horizontal equity of each borough of Seoul appeared to improve each year. Vertical inequity was found to have reverse inequality in most boroughs of Seoul, however, some parts of Gangnam districts such as Gangnam-gu, Seocho-gu, and Gangdong-gu presented progressive inequality. Such example showed the need for improvement in terms of balance by each borough. The use of quantile regression demonstrated reverse inequality in most quantile, but, the differences in the value of the coefficient by each quantile showed the need for improvement of officially assessed land price with the equity of each quantile. Through the equity verification of officially assessed land price, it was analyzed that the lack of equity was found by year, by borough, and by use district. In order to redeem the lack of equity, the government must systematically supplement the real-estate disclosure system by initiating ratio studies to verify horizontal and vertical equity.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.121-129
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• 2021

In this study, we try to minimize the tariff risk by constructing a hazardous cargo screening model by applying Association Rule Mining, one of the data mining techniques. For this, the risk level between supply chains is calculated using the Apriori Algorithm, which is an association analysis algorithm, using the big data of the import declaration form of the Korea Customs Service(KCS). We perform data preprocessing and association rule mining to generate a model to be used in screening the supply chain. In the preprocessing process, we extract the attributes required for rule generation from the import declaration data after the error removing process. Then, we generate the rules by using the extracted attributes as inputs to the Apriori algorithm. The generated association rule model is loaded in the KCS screening system. When the import declaration which should be checked is received, the screening system refers to the model and returns the confidence value based on the supply chain information on the import declaration data. The result will be used to determine whether to check the import case. The 5-fold cross-validation of 16.6% precision and 33.8% recall showed that import declaration data for 2 years and 6 months were divided into learning data and test data. This is a result that is about 3.4 times higher in precision and 1.5 times higher in recall than frequency-based methods. This confirms that the proposed method is an effective way to reduce tariff risks.

• Korean small business review
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• v.43 no.4
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• pp.1-25
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• 2021

As knowledge management is recognized as a core value of organizations, organizations are increasing their investment in policies and technologies for knowledge management. However, since SMEs have relatively few resources to support knowledge sharing, which is the core of knowledge management, there is a possibility that continuous knowledge management will be difficult. This study suggests the negative motivation(job burnout) on the knowledge hoarding of SME employees and the conditions to be improved at the organizational level (shared goal, knowledge sharing culture, and person-organization fit). In this study, a hypothesis was presented through a study related to transaction theory to explain the stress in the relationship between the organization and the individual. This study collected samples through a questionnaire targeting workers of SMEs with knowledge management policies. In addition, the hypothesis was verified by performing structural equation modeling. As a result of the study, shared goal and knowledge sharing culture reduced knowledge hoarding through mitigating job burnout. In particular, person-organization fit moderated the relationship between shared goal, knowledge sharing culture, and job burnout. The study presents academic and practical implications in terms of suggesting factors to mitigate the knowledge hoarding of employees for continuous knowledge management of SMEs.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.849-864
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• 2022

In case of a specific sector being divided into sub-sectors, this study presents a process for estimating an input-output table, which is frequently used as basic data in fields of energy and environment economics. RAS method, which is universally used for this case, requires information on production, intermediate input sum, and intermediate demand sum for each sector in the new table. But in many cases, it is difficult to secure information on intermediate demand sum by sector. This study suggests a process for estimating a new input-output table without using information of intermediate demand sum in the case of sector separation, under the assumption that information of production value and intermediate input sum by sector are available. The key idea is that the values of many elements in the input-output table after disaggregation are the same as those in the table before disaggregation and that the sum of the elements after disaggregation, equals the values of the elements before disaggregation. The process of estimating the intemediate transaction matrix or the input coefficient matrix is presented by using these information instead of intermediate demand sum information. A small-scale simulation shows that the average error rate of the process proposed in this study is about 11.23% in estimating input coefficients, which is smaller than the 11.30% estimation error of RAS using the information of intermediate demand sum. However, since it is known in the literature that using additional information does not always improve estimation performance compared to not using it, additional research on various simulations is needed to apply the method of this study to reality.

• Korea Trade Review
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• v.41 no.2
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• pp.231-250
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• 2016

The study attempts to consider L/G(Letter of Guarantee) in a different angle, which is internationally used as a way of commercial customs and practices in a case when the consignee wants to receive the goods without the original Bill of Lading, Thus, this study focuses more on verifying the usage of L/G in Mixed Payment System and the range of guarantee responsibility by an issuing bank through case analysis. This case uses a mixed payment method of L/C(Letter of Credit) and T/T(Telegraphic Transfer) in the transaction of goods. The issuing bank of L/C issues L/G with the amount of L/C which is the same as the amount as C/I(Commercial Invoice). However the carrier deliver all goods laden under both L/C and T/T payment with the production of L/G. In this case, because the buyer is unable to pay, the seller makes a claim for damages to the carrier that the carrier delivers the goods to the buyer against L/G. Finally, the judge gives a decision that the issuing bank of L/G should pay the whole amount of the goods. In this case, the main issue of the dispute is the range of guarantee responsibility by the issuing bank of L/G. As a result of the case analysis, the study suggests two counter strategies for smooth utilization in international trade environment. First, in the case of mixed payment system, a seller should issue a commercial invoice separately based on the amount of each settlement plan in order to clarify the liability of guarantee. Second, banks should establish a new form for L/G including a sentence for verifying liabilities of the bank's side in the current form of L/G.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.129-141
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• 2024

Amidst the acceleration of digital transformation across various sectors, the financial market is increasingly focusing on the development of digital and electronic payment methods, including currency. Among these, Central Bank Digital Currencies (CBDC) are emerging as future digital currencies that could replace physical cash. They are stable, not subject to value fluctuation, and can be exchanged one-to-one with existing physical currencies. Recently, both domestic and international efforts are underway in researching and developing CBDCs. However, current CBDC systems face scalability issues such as delays in processing large transactions, response times, and network congestion. To build a universal CBDC system, it is crucial to resolve these scalability issues, including the low throughput and network overload problems inherent in existing blockchain technologies. Therefore, this study proposes a solution based on reinforcement learning for handling large-scale data in a CBDC environment, aiming to improve throughput and reduce network congestion. The proposed technology can increase throughput by more than 64 times and reduce network congestion by over 20% compared to existing systems.