• Journal of the Korea Society of Computer and Information
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• v.27 no.3
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• pp.173-182
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• 2022

In this paper, we propose a machine learning model that can prevent fraudulent transactions in advance and interpret them using the XAI approach. For the experiment, we collected a real data set of 12,258 mobile phone sales posts from Joonggonara, a major domestic online C2C resale trading platform. Characteristics of the text corresponding to the post body were extracted using Doc2vec, dimensionality was reduced through PCA, and various derived variables were created based on previous research. To mitigate the data imbalance problem in the preprocessing stage, a complex sampling method that combines oversampling and undersampling was applied. Then, various machine learning models were built to detect fraudulent postings. As a result of the analysis, LightGBM showed the best performance compared to other machine learning models. And as a result of SHAP, if the price is unreasonably low compared to the market price and if there is no indication of the transaction area, there was a high probability that it was a fraudulent post. Also, high price, no safe transaction, the more the courier transaction, and the higher the ratio of 0 in the price also led to fraud.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.13-16
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• 2019

영상이 포함하고 있는 풍부한 정보를 검출하고 이해하기 위해서는, 영상속의 일관된 상호관계를 갖는 영상 객체 그룹을 이해하고 표현하는 영상 구문 검출 기술(Visual Phrase Detecting Technology)이 필수적이다. 영상 구문 검출 기술은, 영상이 포함하고 있는 다양하고 풍부한 정보를 추출하고 활용하기 위한 핵심 기술로 이를 이용한 자동차 주행중 전방 감시, 영상의 자동 주석 달기, 동영상의 검색, 쇼핑 공간에서의 부정행위 검출(fraud detection) 등 다양한 분야에 적용할 수 있다.

• Korean Management Science Review
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• v.21 no.2
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• pp.273-289
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• 2004

Although the Internet is useful for transferring information, Internet auction environments make fraud more attractive to offenders, because the chance of detection and punishment is decreased. One of these frauds is the phantom transaction, which is a colluding transaction by the buyer and seller to commit the illegal discounting of a credit card. They pretend to fulfill the transaction paid by credit card, without actually selling products, and the seller receives cash from the credit card corporations. Then the seller lends it out with quite a high interest rate to the buyer, whose credit rating is so poor that he cannot borrow money from anywhere else. The purpose of this study is to empirically investigate the factors necessary to detect phantom transactions in an online auction. Based upon studies that have explored the behaviors of buyers and sellers in online auctions, the following have been suggested as independent variables: bidding numbers, bid increments, sellers' credit, auction lengths, and starting bids. In this study. we developed Internet-based data collection software and collected data on transactions of notebook computers, each of which had a winning bid of over W one million. Data analysis with a logistic regression model revealed that starting bids, sellers' credit, and auction length were significant in detecting the phantom transactions.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.505-508
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• 2024

금융산업의 디지털 전환은 사용자에게 편리함을 제공하지만 기존에 존재하지 않던 보안상 취약점을 유발했다. 이러한 문제를 해결하기 위해 기계학습 기술을 적용한 사기 거래 탐지 시스템에 대한 연구가 활발하게 이루어지고 있다. 하지만 모델 학습 과정에서 발생하는 데이터 불균형 문제로 인해 오랜 시간이 소요되고 탐지 성능이 저하되는 문제가 있다. 본 논문에서는 실시간 데이터 오버 샘플링을 통해 이상 거래 탐지 시 데이터 불균형 문제를 해결하고 모델 학습 시간을 개선한 새로운 이상 거래 탐지 시스템(Fraud Detection System, FDS)을 제안한다. 본 논문에서 제안하는 SMOTE(Synthetic Minority Oversampling Technique)를 적용한 LSTM(Long-Short Term Memory) 알고리즘 기반의 FDS 프레임워크는 종래의 LSTM 알고리즘 기반의 FDS 모델과 비교했을 때, 데이터 사이즈가 96.5% 감소했으며, 정밀도, 재현율, F1-Score 가 34.81%, 11.14%, 22.51% 개선되었다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.97-108
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• 2001

Frauds detection is a difficult problem, requiring huge computer resources and complicated search activities Researchers have struggled with the problem. Even though a fee research approaches have claimed that their solution is much better than others, research community has not found 'the best solution'well fitting every fraud. Because of the evolving nature of the frauds. a novel and self-adapting method should be devised. In this research a new approach is suggested to solving frauds in insurance claims credit card transaction. Based on evolutionary computing approach, the method is itself self-adjusting and evolving enough to generate a new self of decision-makin rules. We believe that this new approach will provide a promising alternative to conventional ones, in terms of computation performance and classification accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.219-221
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• 2015

스마트폰의 확산으로 금융관련 결제는 어디서나 가능하게 되었기에 편리함이 증가하였다. 하지만, 위와 같은 편리함과 동시에 사용자의 단말이 해커의 공격에 취약하거나 분실할 경우 심각한 문제가 된다. 따라서, 위와 같은 부정행위가 있을 경우 이를 자동으로 탐지하는 시스템이 필요하다. 그러므로, 본 논문은 이러한 문제점을 고려하여 스마트폰을 이용한 금융업무를 처리할때 GPS정보를 적용한 이상금융거래탐지시스템(Fraud Detection System) 모델을 제안한다.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.125-131
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• 2021

Detecting fraudulent insurance claims is difficult due to small and unbalanced data. Some research has been carried out to better cope with various types of fraudulent claims. Nowadays, technology for detecting fraudulent insurance claims has been increasingly utilized in insurance and technology fields, thanks to the use of artificial intelligence (AI) methods in addition to traditional statistical detection and rule-based methods. This study obtained meaningful results for a fraudulent insurance claim detection model based on machine learning (ML) and deep learning (DL) technologies, using fraudulent insurance claim data from previous research. In our search for a method to enhance the detection of fraudulent insurance claims, we investigated the reinforcement learning (RL) method. We examined how we could apply the RL method to the detection of fraudulent insurance claims. There are limited previous cases of applying the RL method. Thus, we first had to define the RL essential elements based on previous research on detecting anomalies. We applied the deep Q-network (DQN) and double deep Q-network (DDQN) in the learning fraudulent insurance claim detection model. By doing so, we confirmed that our model demonstrated better performance than previous machine learning models.

• Journal of KIBIM
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• v.13 no.3
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• pp.12-20
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• 2023

Deep learning-based anomaly detection technology is used in various fields such as computer vision, speech recognition, and natural language processing. In particular, this technology is applied in various fields such as monitoring manufacturing equipment abnormalities, detecting financial fraud, detecting network hacking, and detecting anomalies in medical images. However, in the field of construction and architecture, research on deep learning-based data anomaly detection technology is difficult due to the lack of digitization of domain knowledge due to late digital conversion, lack of learning data, and difficulties in collecting and processing field data in real time. This study acquires necessary data through IoT (Internet of Things) from the viewpoint of monitoring for environmental management of architectural spaces, converts them into a database, learns deep learning, and then supports anomaly patterns using AI (Artificial Infelligence) deep learning-based anomaly detection. We propose an implementation process. The results of this study suggest an effective environmental anomaly pattern detection solution architecture for environmental management of architectural spaces, proving its feasibility. The proposed method enables quick response through real-time data processing and analysis collected from IoT. In order to confirm the effectiveness of the proposed method, performance analysis is performed through prototype implementation to derive the results.

• The Journal of Economics, Marketing and Management
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• v.3 no.1
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• pp.33-39
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• 2015

Managers are always trying to be the best internal controls in their organizations copper approximate because they know that be effective internal control over previous systems, to fulfill the mission of the organization and minimize unexpected events will be extremely difficult. On the other hand, the existence of internal controls to increase efficiency, reduce head loss, assets and achieving a reasonable assurance of the reliability of financial statements and compliance with laws and regulations will be. Internal control, not an event, but a series of operations and activities on the basis of output. Internal controls help to achieve the goal of minimizing the problems of implementing appropriate internal controls. Internal control is an integral component of corporate governance that will provide reasonable assurance of achieving the organization's objectives. preventing, detecting errors and fraud goes to work. Responsibility for the prevention and detection of fraud and error in the public sector is the responsibility of managers. Managers of internal control and consistently applying appropriate accounting systems, this responsibility will play (Lin et al., 2011). Since the public sector organizations differ from each other, thus establishing internal controls cant be the same for all organizations and agencies of the public sector. Establish specific controls on each system to factors such as size, type of operation and organizational goals that the system is designed, it depends. On the other hand, rapid advances in information technology, the need to update internal control guidelines in relation to Create a new computer system so as to ensure that the activities of managers and effective control Should be updated if necessary.

• Advances in environmental research
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• v.12 no.2
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• pp.113-122
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• 2023

Biometric authentication has become an essential part of modern-day security systems, especially in financial institutions like banks. A face recognition-based ATM is a biometric authentication system, that uses facial recognition technology to verify the identity of bank account holders during ATM transactions. This technology offers a secure and convenient alternative to traditional ATM transactions that rely on PIN numbers for verification. The proposed system captures users' pictures and compares it with the stored image in the bank's database to authenticate the transaction. The technology also offers additional benefits such as reducing the risk of fraud and theft, as well as speeding up the transaction process. However, privacy and data security concerns remain, and it is important for the banking sector to instrument solid security actions to protect customers' personal information. The proposed system consists of two stages: the first stage captures the user's facial image using a camera and performs pre-processing, including face detection and alignment. In the second stage, machine learning algorithms compare the pre-processed image with the stored image in the database. The results demonstrate the feasibility and effectiveness of using face recognition for ATM authentication, which can enhance the security of ATMs and reduce the risk of fraud.