• Information Systems Review
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• v.10 no.2
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• pp.269-289
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• 2008

It is very difficult problem to estimate and evaluate the performance of e-government system which scope and size are large and its effectiveness can not be seen shortly but reveals after several years. It is because the previous offline processes can not be transformed to online ones fully and shortly. For such e-transformation cases, the performance evaluation model should be adjusted and modified gradually as time passes. This paper propose new EEM(E-transformation Evaluation Model) model and methodology to evaluate G2B system that is one of large e-government project. EEM model can derive monetary value of e-transformatized business process areas(online areas). It also estimate the expected effect of offline area that is not yet transformed to online. EEM model consists of standard model, verification model and estimation model with some variables such as evaluation year, evaluation area and data type. By using survey data and database data together it can validate the correctness of the model and derive the effect of the system introduction. This paper also propose EEM evaluation methodology consisting of 5 stages and 10 sub processes to evaluate online and offline effect efficiently. To show the usefulness of this study, we evaluate the performance of Korea G2B system named KONEPS which is famous as a successful e-government case in the world by using the proposed model and methodology. The proposed model and methodology can be applied to different similar areas including e-government projects and large scale information system introduction in private sectors. This study can be also used for establishing appropriate policies about e-government project and informatization issues.

• KDI Journal of Economic Policy
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• v.15 no.3
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• pp.131-160
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• 1993

본고(本稿)에서는 다양한 형태의 금융충격(金融衝擊)의 거시경제효과(巨視經濟效果)를 분석하기 위해, 모든 금융충격(金融衝擊)을 통화의 지불수단으로서의 이용률(利用率)을 급격하게 변화시킴으로써 화폐시장(貨幣市場)에 초과수요나 초과공급을 초래하는 현상으로 이해하고, 동 충격을 유통속도충격(流通速度衝擊)과 통화승수충격(通貨乘數衝擊)으로 분리하여 그 규모를 추정할 수 있도록 전자(前者)는 은행의 예금회전율(預金回轉率)과 현금통화보유성향(現金通貨保有性向)에 의해, 후자(後者)는 현금통화보유성향과 지급준비보유성향에 의해 설명하는 일반적인 모형을 개발했다. 동 모형을 아용하여 80년대 이후 우리나라의 금융충격사례(金融衝擊事例)에 대해 분석한 결과는 다음과 같다. 82년 거액어음사기사건과 7.3조치에 의한 실명제예고조치(實名制豫告措置)는 M2를 3% 이상 감소시키는 효과를 초래하였으나, 실제로는 통화당국의 대응으로 오히려 3.0% 수준의 M2가 초과공급된 반면, 1988년의 금융실명제(金融實名制) 실시예고와 민간(民間)에 의한 1993년 8월 12일의 금융실명제실시예견은 M2를 각각 3.9% 및 4.9% 감소시키는 효과를 초래하여 정부의 통화공급대응(通貨供給對應)에도 불구하고 결과적으로는 각각 0.8% 및 0.6% 수준의 M2 과소공급을 초래한 것으로 추정되었다. 93년 8월 12일의 금융실명제 전격실시는 개략적으로 7~8%의 M2 통화량감소효과를 초래한 것으로 추정되지만, 실제로는 통화당국(通貨當局)의 신축적 통화공급으로 0.3~0.6% 정도의 M2 초과공급이 이루어진 것으로 추정되었다. 한편 본고(本稿)에서는 이와 같이 추정된 사례별 금융충격의 거시경제효과(巨視經濟效果) 시뮬레이션 결과(結果)도 같이 보여주고 있다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.2
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• pp.197-212
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• 2020

With the advent of virtual currency and electronic wallets creating a way to make financial gains based on anonymity, malicious code dissemination using malicious mail has continued to increase. In order to minimize the damage, the human factors, security awareness and the ability to respond, which are technical factors, should be improved evenly, which can be improved through malicious mail training. This study presented a model considering the performance of malicious mail training, such as practice. It was classified as a training for enhancing awareness of security for employees and detection and response to improve their ability to respond to malicious mail. A training system suitable for the purpose, the core functions of malware training, implementation and camouflage skills, and bypass techniques were described. Based on the above model, the training data conducted over three years were collected and the effectiveness of the training was studied through analysis of the results according to the number of training sessions, training themes and camouflage techniques.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.25-32
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• 2019

The core of the block chain technology is solving the problem of agreement on double payment, and the PoW, PoS and DPoS algorithms used for this have been studied. PoW in-process proofs are consensus systems that require feasible efforts to prevent minor or malicious use of computing capabilities, such as sending spam e-mail or initiating denial of service (DoS) attacks. The proof of the PoS is made to solve the Nothing at stake problem as well as the energy waste of the proof of work (PoW) algorithm, and the decision of the sum of each node is decided according to the amount of money, not the calculation ability. DPoS is that a small number of authorized users maintain a trade consensus through a distributed network, whereas DPS provides consent authority to a small number of representatives, whereas PoS has consent authority to all users. If PoS is direct democracy, DPoS is indirect democracy. This study aims to contribute to the continuous development of the related field through the study of the algorithm of the block chain agreement.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.13-21
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• 2019

The restricted network or the unbalanced distribution of spectrum is causing the problems of lack of spectrum resources and deterioration of the service quality. In addition, the existing centralized radio sharing method has not been a fundamental solution for radio sharing and is inefficient in terms of cost, convenience, and security. In this paper, we propose a blockchain-based spectrum sharing as a low-cost, trustworthy, high-efficiency platform that can distribute and share spectrum resources, and propose policies to realize this. In the spectrum sharing platform, spectrum information about Wi-Fi AP and LTE mobile hotspot is registered in the blockchain, and spectrum sharers and users can conclude peer-to-peer spectrum sharing contract quickly and efficiently through smart contract. The pay for the shared spectrum resources and reward for spectrum quality management open platform ecosystem to activate the circulation-sharing and it can provide a convenient and efficient public wireless infrastructure.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.6
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• pp.27-40
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• 2001

In an offline system, the bank does not participate in payments. As a result, it is difficult to make the refund spendable. Due to this, current offline systems do not provide spendable refunds. In these systems, a check consists of two parts: a spendable part and a refund part. A client uses the spendable part during the payment phase, and uses the refund part to get the refund for the remainder of the check. Therefore, a client cannot reuse the remaining and must always refund it. Moreover, the relationship between the spent amount and the refund amount can be used to guess which check the client used when the client refunds the remaining. To remedy these problems, we propose a new offline system which allow clients to reuse the remaining values of the check. This system provides unlinkability of the payments made by using a single check. It also provides mechanisms to detect and identify clients who perform misconduct such as double spending and over spending. The required overall computational cost to withdraw, spend and refund a check in our system is lower than using several checks in other offline systems.

• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.50-60
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• 2009

Recently, the traffic card is gradually utilized and its several supplementary services have been significantly developed. Particularly, since it is possible to pay fees for buses, taxies, subways, parking and tollgates with only one traffic card, new payment method for economically processing has been focused. This paper presents a new receipt management system which allows possibly paying with several digital cards through PC interfacing terminals. The proposed system is mainly composed of three parts: terminals, middleware, and management servers. A terminal part includes processing module for payment/charging and credit/check/debit cards, etc and its operation is fulfilled through a middleware part. A main task of a middleware part is to connect a terminal part to managing servers through middleware applications. Additionally, processing of several receipt items and monitoring of the terminals to product statistical reports based on the processed result are carried out in the middleware. A management sever part is accomplished for collecting all of transaction histories against users and charging items over allowed province and managing statistical information. The proposed system is currently utilized in the Nam-GU district office and the Nam-GU district health center, Busan, S. Korea, respectively for testing its effectiveness. We conclude from this demonstration that the system is more useful and efficient than the previous processing method especially in that variable payment ways are provided and consumption burden is reduced.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.4
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• pp.33-41
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• 2006

RSA cryptosystem is of great use in systems such as IC card, mobile system, WPKI, electronic cash, SET, SSL and so on. RSA is performed through modular exponentiation. It is well known that the Montgomery multiplier is efficient in general. The critical path delay of the Montgomery multiplier depends on an addition of three operands, the problem that is taken over carry-propagation makes big influence at an efficiency of Montgomery Multiplier. Recently, the use of the Carry Save Adder(CSA) which has no carry propagation has worked McIvor et al. proposed a couple of Montgomery multiplication for an ideal exponentiation, the one and the other are made of 3 steps and 2 steps of CSA respectively. The latter one is more efficient than the first one in terms of the time complexity. In this paper, for faster operation than the latter one we use binary signed-digit(SD) number system which has no carry-propagation. We propose a new redundant binary adder(RBA) that performs the addition between two binary SD numbers and apply to Montgomery multiplier. Instead of the binary SD addition rule using in existing RBAs, we propose a new addition rule. And, we construct and simulate to the proposed adder using gates provided from SAMSUNG STD130 $0.18{\mu}m$ 1.8V CMOS Standard Cell Library. The result is faster by a minimum 12.46% in terms of the time complexity than McIvor's 2 method and existing RBAs.

• Journal of the Korean Society for information Management
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• v.38 no.3
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• pp.23-39
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• 2021

This study aims to explore research trends in Blockchain studies in South Korea using dynamic topic modeling and network analysis. To achieve this goal, we conducted the university & institute collaboration network analysis, the keyword co-occurrence network analysis, and times series topic analysis using dynamic topic modeling. Through the university & institute collaboration network analysis, we found major universities such as Soongsil University, Soonchunhyang University, Korea University, Korea Advanced Institute of Science and Technology (KAIST) and major institutes such as Ministry of National Defense, Korea Railroad Research Institute, Samil PricewaterhouseCoopers, Electronics and Telecommunications Research Institute that led collaborative research. Next, through the analysis of the keyword co-occurrence network, we found major research keywords including virtual assets (Cryptocurrency, Bitcoin, Ethereum, Virtual currency), blockchain technology (Distributed ledger, Distributed ledger technology), finance (Smart contract), and information security (Security, privacy, Personal information). Smart contracts showed the highest scores in all network centrality measures showing its importance in the field. Finally, through the time series topic analysis, we identified five major topics including blockchain technology, blockchain ecosystem, blockchain application 1 (trade, online voting, real estate), blockchain application 2 (food, tourism, distribution, media), and blockchain application 3 (economy, finance). Changes of topics were also investigated by exploring proportions of representative keywords for each topic. The study is the first of its kind to attempt to conduct university & institute collaboration networks analysis and dynamic topic modeling-based times series topic analysis for exploring research trends in Blockchain studies in South Korea. Our results can be used by government agencies, universities, and research institutes to develop effective strategies of promoting university & institutes collaboration and interdisciplinary research in the field.