• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.837-841
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• 2009

언제, 어디서나 컴퓨터 사용과 통신이 가능한 유비쿼터스 환경의 구축과 개발은 부존자원이 부족한우리나라의 산업 전략에 부합하며 현재 우리나라가 보유한 정보통신 관련기술의 우위를 바탕으로 성장할 가능성이 큰 분야로써 정부가 미래의 10대 성장 동력으로 선정한 분야의 한가지 이다. 배전시스템에서의 이 분야 기술 개발의 핵심내용은 유비쿼터스 기술을 활용한 고 신뢰도의 배전계통 운용 및 높은 수준의 전기품질 관리체제 구축 그리고 이를 통한 관련 산업 즉, 전력거래, 전력시장 유지 및 운영을 위한 핵심 세부 콘텐츠와 부가서비스의 창출을 위한 기반 인프라의 개발 및 구축에 있는데, 이 기반기술의 중심에 배전시스템이 있으므로 이를 고 신뢰, 고품질 기반의 시스템으로 지능화하는 것이 필요하다. 따라서 본 논문에서는 태양광, 풍력 등의 분산전원이 계통에 연계되는 장래의 스마트배전시스템에 대하여, 기존의 배전계통의 전압조정방안과 비교, 분석하여 기술적인 적합여부를 종합적으로 평가하고자 한다.

• Journal of Internet of Things and Convergence
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• v.8 no.5
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• pp.55-61
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• 2022

Today's payment systems are becoming unmanned and changing to a way of paying with kiosks. This has the advantage of convenient payment because consumers can select a menu and specify the number of products to be purchased with just a touch of the screen. However, from the point of view of system security, the actual kiosk system has various vulnerabilities. This can hijack the administrator account, gain system privileges, and perform malicious actions. In addition, it is exposed to a number of security threats, such as the possibility of wasting unnecessary resources by abnormally increasing the number of payments, and causing the device to fail to operate normally. Therefore, in this paper, if any node of a participant in the solana blockchain approves an incorrect fork, the stake of the voting nodes is deleted. Also, since all participants can see the transaction history due to the nature of the block chain, I intend to write a thesis on a system that improves the vulnerability of kiosk payments by separating the access rights through the private blockchain.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.5
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• pp.165-170
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• 2023

With the recent rise of blockchain technology, cryptocurrency platforms using it are increasing, and currency transactions are being actively conducted. However, crimes that abuse the characteristics of cryptocurrency are also increasing, which is a problem. In particular, phishing scams account for more than a majority of Ethereum cybercrime and are considered a major security threat. Therefore, effective phishing scams detection methods are urgently needed. However, it is difficult to provide sufficient data for supervised learning due to the problem of data imbalance caused by the lack of phishing addresses labeled in the Ethereum participating account address. To address this, this paper proposes a phishing scams detection method that uses both Trans2vec, an effective graph embedding techique considering Ethereum transaction networks, and semi-supervised learning model Tri-training to make the most of not only labeled data but also unlabeled data.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.59-68
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• 2007

The purpose of this paper is to evaluate usability quality through investigating the factors of usability for internet shopping mall websites. For this study, previous studies were investigated and experts' discussions were held. In result, six characters of usability were chosen such as content satisfaction. customer attraction satisfaction, price information satisfaction, public security satisfaction, user interface satisfaction. and process of transaction satisfaction that affect usability of shopping mall websites and the evaluation models of 72 detailed measure factors were established. Since these 72 sub-factors inc)ode the key words of HTML, XML, JSP, and ASP from the target websites. 33 measurable sub-factors in the information were measured through usability evaluation experiment. In addition, a questionnaire about usability measure factors was executed after preferable websites and not preferable websites are selected. After that, we verified the reasonability of usability measure model factors comparing the results of the evaluation experiment with the result of the questionnaire. The time it takes to measure the usability of shopping mall websites can be reduced by using this measurement supporting tool. Also, this tool may be used to estimate the usability during the development of a shopping mall website.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.31-40
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• 2021

Blockchain technology is also actively studied in the real estate transaction field, and real estate transactions have various ways. In this paper, we propose a model that simplifies the authentication procedure of auction systems using Ethereum's Ether to solve the problem of offline court auctions. The proposed model is written in Ethereum's Solidity language, the court registers the sale date and the sale date with the DApp browser, and the bidder accesses the address of the individual's wallet created through Metamask's private key. The bidder then selects the desired sale and enters the bid price amount to participate in the auction. The bidder's record of the highest bid price for the sale he wants is written on the Ethereum test network as a smart contract. and creates a block. Finally, smart contracts written on the network are distributed by the court auction manager to all nodes in the blockchain network, and each node in the blockchain network can be viewed and contract verified. As a result of analyzing the smart contracts of the proposed model and the performance of the system, there are fees incurred due to the creation and use of Ether on platforms using Ethereum, and participation. Ether's changes in value affect the price of the sale, resulting in inconsistent fees in smart contracts each time. However, in future work, we issue our own tokens to solve the market volatility problem and commission problem with the value change of Ether, and refine complex court auction systems.

• Korean Security Journal
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• no.10
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• pp.323-354
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• 2005

As with the vast array of computer technology and its rapid development, along with the entry of the internet as one of the necessities of life, the so-called cyber space has become a vital component of our modern day living. While such cyber space has provided the society with much convenience and utility as to the gathering and acquiring of information, crimes involving cyber space has accordingly increased in both number and form, Nevertheless, the conventional law as existed before the development of the cyber space were unable to meet the demands of this new breed of crime, which inevitably led to the gap in the government ability to punish such criminals, Thus, in response to the rising number of cyber crimes, a large number of nations have either created or is in the process of committing human and financial resources to strengthen the investigative powers relating to cyber crimes and creating a new area of prohibiting such crimes. As a overview of cyber crime, (1)defines the terms, describes features of cyber crime, (2)explains the international prevention necessity of cyber crime, and (3)the necessity of legislating the cyber crime Fundamental Act (4)the recognition of the evidential values on the confiscated electronic records and reviews types of cyber crime including cyberterror. Lastly, emphasizes necessity on international cooperation for prevention of cyber crime as usual.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.137-146
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• 2012

In SCM(Supply Chain Management), a management paradigm where the customer satisfaction is to be achieved by minimizing the cost, reducing the uncertainty, and obtaining the overall optimization. As it performs the integrated operation of the paths of information, assets, and knowledge from the raw material providers to the retailers, the adoption of RFID(Radio Frequency Identification) in SCM could be expected to magnify the effectiveness of the system. However, there is a huge risk by deciding whether or not RFID system is adopted without the objective analysis under the uncertain circumstances. This research paper presents the statistical analysis methodologies for the comparison of RFID with Barcode on the aspect of utility and the statistical analysis tool, RUSAT, which was programmed for nonstatisticians' convenience. Assuming a pharmaceutical industry, this paper illustrates how the data were entered and analyzed in RUSAT. The results of this research are expected to be used not only for the pharmaceutical related company but also for the manufacturer, the whole-saler, and the retailer in the other logistic industries.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.129-138
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• 2014

The Electronic contract means creation sign management and storage of contract by online without limitations of the time and space through the electronic signature and encode which based on the Certificate instead of the past that treatment the contract such as creation sign management and storage of contract by face-to-face. Recently, the remarkable development of information and communication technology with supplying the high-speed Internet services. Accordingly, the transaction contract made by these also, the steady legal effect occurred by two or more parties by legal action which is the electronic agreement of expression. and it makes agreement improving corporate productivity and it can control the whole process such as contract documents and the actual buying store provision. Like this it has many benefits so, it suddenly rising as the new axis of economic activity area, it is a reality. In this change of era, with the establishment of electronic contracts, there are many problems are occurred to the expression of parties which is core of the contract on civil code so, the systematic legal composition is required. Thus, in this study will propose the reasonable improvements about the issue of electronic contract through the consideration.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.13-21
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• 2010

One of the most distinguished features of the DHP association rules mining algorithm is that it counts the support of hash key combinations composed of k items at phase k-1, and uses the counted support for pruning candidate large itemsets to improve performance. At this time, it is desirable for each hash key combination to have a separate count variable, where it is impossible to allocate the variables owing to memory shortage. So, the algorithm uses a direct hashing mechanism in which several hash key combinations conflict and are counted in a same hash bucket. But the direct hashing mechanism is not efficient because the distribution of hash key combinations is unvalanced by the characteristics sourced from the mining process. This paper proposes a mapped perfect hashing function which maps the region of hash key combinations into a continuous integer space for phase 3 and maximizes the efficiency of direct hashing mechanism. The results of a performance test experimented on 42 test data sets shows that the average performance improvement of the proposed hashing mechanism is 7.3% compared to the existing method, and the highest performance improvement is 16.9%. Also, it shows that the proposed method is more efficient in case the length of transactions or large itemsets are long or the number of total items is large.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.147-155
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• 2022

In this study, we developed a system to dynamically balance a daily stock portfolio and performed trading simulations using gradient boosting and genetic algorithms. We collected various stock market data from stocks listed on the KOSPI and KOSDAQ markets, including investor-specific transaction data. Subsequently, we indexed the data as a preprocessing step, and used feature engineering to modify and generate variables for training. First, we experimentally compared the performance of three popular gradient boosting algorithms in terms of accuracy, precision, recall, and F1-score, including XGBoost, LightGBM, and CatBoost. Based on the results, in a second experiment, we used a LightGBM model trained on the collected data along with genetic algorithms to predict and select stocks with a high daily probability of profit. We also conducted simulations of trading during the period of the testing data to analyze the performance of the proposed approach compared with the KOSPI and KOSDAQ indices in terms of the CAGR (Compound Annual Growth Rate), MDD (Maximum Draw Down), Sharpe ratio, and volatility. The results showed that the proposed strategies outperformed those employed by the Korean stock market in terms of all performance metrics. Moreover, our proposed LightGBM model with a genetic algorithm exhibited competitive performance in predicting stock price movements.