• Journal of Intelligence and Information Systems
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• v.21 no.1
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• pp.161-177
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• 2015

With the rapid evolution of technology, the size, number, and the type of databases has increased concomitantly, so data mining approaches face many challenging applications from databases. One such application is discovery of fraud patterns from agricultural product wholesale transaction instances. The agricultural product wholesale market in Korea is huge, and vast numbers of transactions have been made every day. The demand for agricultural products continues to grow, and the use of electronic auction systems raises the efficiency of operations of wholesale market. Certainly, the number of unusual transactions is also assumed to be increased in proportion to the trading amount, where an unusual transaction is often the first sign of fraud. However, it is very difficult to identify and detect these transactions and the corresponding fraud occurred in agricultural product wholesale market because the types of fraud are more intelligent than ever before. The fraud can be detected by verifying the overall transaction records manually, but it requires significant amount of human resources, and ultimately is not a practical approach. Frauds also can be revealed by victim's report or complaint. But there are usually no victims in the agricultural product wholesale frauds because they are committed by collusion of an auction company and an intermediary wholesaler. Nevertheless, it is required to monitor transaction records continuously and to make an effort to prevent any fraud, because the fraud not only disturbs the fair trade order of the market but also reduces the credibility of the market rapidly. Applying data mining to such an environment is very useful since it can discover unknown fraud patterns or features from a large volume of transaction data properly. The objective of this research is to empirically investigate the factors necessary to detect fraud transactions in an agricultural product wholesale market by developing a data mining based fraud detection model. One of major frauds is the phantom transaction, which is a colluding transaction by the seller(auction company or forwarder) and buyer(intermediary wholesaler) to commit the fraud transaction. They pretend to fulfill the transaction by recording false data in the online transaction processing system without actually selling products, and the seller receives money from the buyer. This leads to the overstatement of sales performance and illegal money transfers, which reduces the credibility of market. This paper reviews the environment of wholesale market such as types of transactions, roles of participants of the market, and various types and characteristics of frauds, and introduces the whole process of developing the phantom transaction detection model. The process consists of the following 4 modules: (1) Data cleaning and standardization (2) Statistical data analysis such as distribution and correlation analysis, (3) Construction of classification model using decision-tree induction approach, (4) Verification of the model in terms of hit ratio. We collected real data from 6 associations of agricultural producers in metropolitan markets. Final model with a decision-tree induction approach revealed that monthly average trading price of item offered by forwarders is a key variable in detecting the phantom transaction. The verification procedure also confirmed the suitability of the results. However, even though the performance of the results of this research is satisfactory, sensitive issues are still remained for improving classification accuracy and conciseness of rules. One such issue is the robustness of data mining model. Data mining is very much data-oriented, so data mining models tend to be very sensitive to changes of data or situations. Thus, it is evident that this non-robustness of data mining model requires continuous remodeling as data or situation changes. We hope that this paper suggest valuable guideline to organizations and companies that consider introducing or constructing a fraud detection model in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.200-213
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• 2018

Herein, we survey the current state of the recent legal revision of the Citizens Broadband Radio Service, a type of city spectrum-sharing service used in the United States of America, and the introduction of spectrum sharing in the frequency ranging from 3.8~4.2 GHz, based on the United Kingdom framework for spectrum sharing. Specifically, the subjects of topical interest, including the radio station licensing of the spectrum-sharing service system face-to-face multitier user structure, regional frequency allocation, and applicable service types, are discussed. Furthermore, factors to be considered while selecting candidate channels for joint use are suggested, emphasizing their importance for introducing spectrum sharing in Korea and revitalizing the related industrial sectors. In addition, methods of introducing a radio station license system for spectrum sharing, techniques of introducing incentive auctions, and the types of services where spectrum sharing is applicable are discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.8
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• pp.805-819
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• 2013

In this paper, we analyze the paradigm shift of radio policy with the development of radio technology. In particular, we propose the definition of spectrum sharing, which is now omitted in the Korean radio law, and analyze the category of spectrum sharing depending on the licensing regime. Also we propose to extend the spectrum usage right, which defines only exclusive usage rights by spectrum auction in the Korean radio law, to all the stations which use radio spectrum and to restructure the Korean radio law.

• Journal of the Korean Society for Library and Information Science
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• v.38 no.4
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• pp.149-166
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• 2004

This study make comparative analysis of the cataloging rules on the edition area included in the KCR4, NCR(2001), AACR2R, ISBD(M), and ISBD(ER). There is a delicate difference between the cataloging rules. The main features on the edition are as the follows. (1) In the bibliography description the concept of the edition is a general application. That is to say, the edition construct the new edition and the impression. The former comes the purview of a change content, the size, and a printing type. The latter publish newly- (2) The requisite for description of the edition area consists of a edition statement, statements of responsibility relating to the edition, additional edition statement, and statements of responsibility following an additional edition statement. Voluntary rules transcribe the parallel edition statement. (3) In the case of the electronic materials special versions on content and Auction indicates as the edition, but the environment of software does not indicate as it. (4) Parallel statement of responsibility relating to the edition, parallel additional edition statements, and parallel statements of responsibility following an additional edition statement are voluntary rules or not transcribed in the edition area.

• The Journal of Information Technology
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• v.6 no.4
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• pp.69-80
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• 2003

The electronic commerce continues to grow dramatically. Also, consumer complaints and damages related to e-commerce grow rapidly. The analysis of consumer complaints showed that consumer of e-commerce tended to buy the various product categories including cloth and home appliance. The damages of delivery problem rapidly rose by 1,185.3%. In categories of transaction including of 'internet shopping mall', 'internet contents' and 'internet auction', about 90% of consumer damages was related to 'internet shopping mall' but consumer damages of 'internet contents' was anticipated to be increased in the near future. The major goods and services of damages was 'digital camera', notebook PC', 'internet game service' etc. Therefore, it is required to establish consumer protection measures to be prevent consumer fraud such as internet shopping mall, Halfplaza.com, and major goods and services of damages. Also, it is need to establish system of spontaneous consumer protection improving consciousness of e-commerce companies.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.9
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• pp.477-486
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• 2003

In combinatorial auctions buyers nay bid for arbitrary combinations of goods. But determining the winners of combinatorial auctions who maximize the profit of a seller is known to be NP-complete. A branch-and-bound method can be one of practical algorithm for winner determination. However, bid selection heuristics play a very important role in the efficiency of a branch-and-bound method. In this paper, we designed and implemented an algorithm which used a branch-and-bound method and Linear Programming for winner determination in combinatorial auctions. We propose new bid selection heuristics which consider a branching bid and conflicting bids simultaneously to select a branching bid in the algorithm. In addition, upper bounds are reused to reduce the running time in specific cases. We evaluated the performance of the algorithm by experiments with five data distributions and compared our method with others. The algorithm using heuristics showed a superior efficiency in two data distributions and a similar efficiency in three distributions.