• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.129-136
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• 2003

A representative payment broker system is SET and one of its signature shcemes is a dual digital signature scheme. A dual digital signature scheme expose neither user's payment information(credit card number etc.) to merchandiser, nor user's order information to bank So it keeps user's Privacy safe. The digital signature scheme like this is being necessary as E-commerce is revitalized. But a dual digital signature of SET is not appropriate for wireless environments because it needs so many computations and communications. In this paper, we propose a signcryption scheme that generates a polynomial using a payment information for merchandiser and an order information for bank in order to reduce communications. We analyze the problem of existing signcryption schemes and dual digital signature schemes. Also we analyze the security properties of the proposed scheme.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.11-16
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• 2021

Recently, community welfare centers including the elderly welfare centers are also interested in the issue of loneliness and are attempting a comprehensive approach to care for the elderly in the community.The problem is that there is a need for volunteers who are sustainable, but trained semi-professionals rather than non-professionals.Therefore, ways to provide education programs that can be based on continuous supplementation and specialization of manpower and to apply them to the field are being sought.The purpose of this study is to present a plan through examples with the aim of linking college students majoring in social welfare as a major resource for preventing loneliness of elderly people living alone in local communities through volunteer activities. It was suggested that volunteer activities of college students majoring in social welfare should be provided more systematically to the elderly living alone in the community.

• The Korean Journal of Financial Management
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• v.22 no.1
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• pp.1-36
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• 2005

In this study, we analyzed determinant factors of leverage ratio and debt maturity for Korean firms in the simultaneous equation system using 2SLS (two stage least square) method under assumption that two variables are jointly determined in the capital structure decision. As a result of the analysis, we found that leverage ratio and debt maturity are positively related. Also, as for determinant factors of debt maturity, agency cost hypothesis, asset maturity matching hypothesis, signalling and liquidity risk hypothesis are all generally supported, and further leverage ratio are significantly positively related with firm size, but negatively related with default risk. However, when we divided samples into groups according to bank debt level and Chaebul affiliation, with contrast to existing study which worked on similar issues with OLS, we found no evidence supporting the argument that the information asymmetry problem is less severe in firms with more bank debt, whereas information asymmetry and financial constraint problems are more severe in non-Chaebul affiliated firms.

• Economic Analysis
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• v.27 no.4
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• pp.1-42
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• 2021

The outlook for Korea's consumer price inflation rate has a profound impact not only on the Bank of Korea's operation of the inflation target system but also on the overall economy, including the bond market and private consumption and investment. This study presents the prediction results of consumer price inflation in Korea for the next three years. To this end, first, model selection is performed based on the out-of-sample predictive power of autoregressive distributed lag (ADL) models, AR models, small-scale vector autoregressive (VAR) models, and large-scale VAR models. Since there are many potential predictors of inflation, a Bayesian variable selection technique was introduced for 12 macro variables, and a precise tuning process was performed to improve predictive power. In the case of the VAR model, the Minnesota prior distribution was applied to solve the dimensional curse problem. Looking at the results of long-term and short-term out-of-sample predictions for the last five years, the ADL model was generally superior to other competing models in both point and distribution prediction. As a result of forecasting through the combination of predictions from the above models, the inflation rate is expected to maintain the current level of around 2% until the second half of 2022, and is expected to drop to around 1% from the first half of 2023.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.68
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• pp.1-21
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• 2015

The purpose of this study is to propose a new mechanism for the global transmission of electronic trade documents and to promote them using it. Trade settlement methods are changed from L/C bases to non-L/C bases and in particular, the telegraphic transfer is dramatically increased since mid 1990. But the status of transmission of electronic trade documents still rely on the letter of credit and bill of lading. So it need to change the process of transmission of electronic trade documents utilizing non-negotiable sea waybill instead of bill of lading. In this study, I pointed out two problems as obstacle factors in global transmission of electronic trade documents. First is the system connection problem between domestic and foreign banks and second is the electronic right transfer problem in the bill of lading. Electronic bill of lading has already been made, but are not used and e-Nego has also not been activated under the above issues. Therefore, it should be solved previously the above problems for the global transmission of electronic trade documents under the letters of credit. However, in transactions of transfer, it does not need the inter-bank connection and also does not occur the electronic right transfer problem of bill of lading if using the non-negotiable seaway bill instead of bill of lading. In this paper, I recommend the global transmission strategies of e-trade documents using the non-negotiable sea waybill in transactions of transfer. Hopefully, I expect the activation of global transmission of e-trade documents through the utilization of electronic non-negotiable sea waybill as suggested by this study.

• The Journal of Korean Association of Computer Education
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• v.22 no.3
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• pp.55-65
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• 2019

In programming language learning system of flip learning methods, the evaluation of cyber lectures generally proceeds from online to multiple choice questions. In this case, the questions are randomly extracted from the question bank and given to individual learners. In order for these evaluation results to be reflected in the grades, the equity of the examination question is more important than anything else. Especially in the programming language subject, the degree of difficulty that learners think can be different depending on the type of problem. In this paper, we classify the types of multiple-choice problems into two categories, and manage the difficulty level by each type. And we propose a question selection algorithm that considers both difficulty level and type of question. Considering the characteristics of the programming language, experimental results show that the proposed algorithm is more efficient and fair than the conventional method.

• Journal of Environmental Impact Assessment
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• v.21 no.6
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• pp.823-839
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• 2012

Environmental Specimen Banks (ESBs) are playing pivotal role in monitoring the effect of environmental pollution on the ecosystem based on the retrospective analysis of the representative samples collected regularly and stored in cryogenic condition. In Korea, National Environmental Specimen Bank (NESB) was established in 2009 and the standard operating procedures (SOPs) for sampling, and cryogenic milling and storage had been prepared during 2007-2010. Since then, the tentative SOPs for the seven kinds of specimens (shoots of Red Pine (Pinus densiflora) and Korean Pine (Pinus koraiensis), leaves of Mongolian Oak (Quercus mongolica) and Zelkova Tree (Zelkova serrata), eggs of Feral Pigeon (Columba livia var. domestica), muscles and organs of Common Carp (Cyprinus carpio), and Freshwater Bivalve (Unio (Nodularia) douglasiae)) have been put to test in the field and laboratory as well against the practicality and feasibility. The SOPs were improved by reflecting the findings from the research and the following discussion regarding the selection of specimen (Feral Pigeon suffering from a control management), sample size (a problem of decreasing number of sampling trees related to increasing sampling time) and period (a problem related to a bud growth), and sampling methods etc.. In addition, barcoding system for the management of the specimen information, and monitoring system of the cryogenic storage to regulate the optimum temperature and the liquid nitrogen level were also developed for the efficient and effective control of the samples. Lastly, the safety guide and emergency protocol were augmented to guarantee a safe work environment with the cryogenic facility. These improvements of the SOPs are expected to contribute to more stable operation of the NESB.

• Journal of International Area Studies (JIAS)
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• v.14 no.2
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• pp.499-524
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• 2010

The purpose of this study is to based on review of theoretical and empirical studies to assess the independence of central banks - the former Socialist republics, including the Russian Federation and Czech, Poland. In addition, the work is expected to clarify whether a link exists between independence and the most important economic indicators such as inflation, economic activity, the budget deficit. And The subject of this study are the formal and actual independence of national banks, as well as limiting factors: political and economic. Background investigation of the problem of independence of central banks from the fact that, according to many economists, it is essential to the successful development of a market economy. The effectiveness of any country's economy due to currency volatility, low inflation, high reliability of the banking system, etc. As far as the independence of monetary regulation contributes to these goals - one of the most actively debated issues in the world of economic theory and practice for a long time. The issue of central bank independence is extremely important for Russia, Czech, Poland. In the near future to the central bank has important tasks, among which are the transition to inflation targeting in the rejection of significant intervention in the foreign exchange market, as well as improving the sustainability of the national banking system. Transparency and independence of the Bank of Russia, Czech Republic, Poland, in my view, should be an important factor in achieving these goals. The countries of Czech Republic, Poland have already made a number of steps to bring the status of their banks to the European standards. Many other developing countries are also in the process of reforming their central banks and the improving conditions of their functioning. However, despite the fact that as a model for reform used by the central banks of countries with developed market economies, central banks in developing countries are still yet deprived of the legal, economic and political independence. A different situation exists in transition space. Because of significant differences in the views of the authorities in transition republics at the necessary level of independence of central banks and the exchange rate and monetary policy reform of monetary management in these countries led to different results.

• Journal of The Korean Association For Science Education
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• v.40 no.4
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• pp.385-398
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• 2020

This study aims to examine genetics problem-solving processes of high school students with different learning approaches. Two second graders in high school participated in a task that required solving the complicated pedigree problem. The participants had similar academic achievements in life science but one had a deep learning approach while the other had a surface learning approach. In order to analyze in depth the students' problem-solving processes, each student's problem-solving process was video-recorded, and each student conducted a think-aloud interview after solving the problem. Although students showed similar errors at the first trial in solving the problem, they showed different problem-solving process at the last trial. Student A who had a deep learning approach voluntarily solved the problem three times and demonstrated correct conceptual framing to the three constraints using rule-based reasoning in the last trial. Student A monitored the consistency between the data and her own pedigree, and reflected the problem-solving process in the check phase of the last trial in solving the problem. Student A's problem-solving process in the third trial resembled a successful problem-solving algorithm. However, student B who had a surface learning approach, involuntarily repeated solving the problem twice, and focused and used only part of the data due to her goal-oriented attitude to solve the problem in seeking for answers. Student B showed incorrect conceptual framing by memory-bank or arbitrary reasoning, and maintained her incorrect conceptual framing to the constraints in two problem-solving processes. These findings can help in understanding the problem-solving processes of students who have different learning approaches, allowing teachers to better support students with difficulties in accessing genetics problems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.2
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• pp.69-80
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• 2003

Verifiable encryption is an encryption technique with which one can verify what has been encrypted even if one can not decrypt the ciphertext. This technique can be used in fair exchange to convince the counterpart of his or her receiving an item by presenting an encrypted form in advance. In this paper, a method that can guarantee the payment atomicity is proposed by applying verifiable encryption to an electronic cash system based on the representation problem. With the new method, the process of dispute settlement is improved in the fact that the trusted third party do not have to interact with the bank to resolve disputes. This method is also flexible in a sense that clients and shops can request for dispute settlement regardless of any deadline constraint. However, additional proof is necessary to apply verifiable encryption during payment. We discuss the security and the atomicity of our method, and compare ours with others.