• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.158-164
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• 2009

The real time security system using web camera shall correspond in commensurate with it in real time through classifying moving object and analyzing the behavior. But, as to the detection of moving object in real time image through a camera, it is difficult to detect movement correctly according to the change of unnecessary noises, lighting conditions and screened phenomenon. This paper proposes real time security system by dual camera and ultrasonic sensor, a method of advanced detection in order to detect correct movement of specific object. That is, we could improve the tracing characteristics by using ultrasonic sensor as measurement factor of changed position and verify through experiments that the information interchanged between camera upwards and in front of it have effect on tracing a specific object continuously. The results of the experiment show that recognition rate of object was 97.4% and the correct tracing could be done lastingly in a phenomena of screening object.

• Journal of Power Electronics
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• v.16 no.2
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• pp.685-694
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• 2016

This paper presents a reliability assessment model for the power semiconductors used in wind turbine power converters. In this study, the thermal loadings at different timescales of wind speed are considered. First, in order to address the influence of long-term thermal cycling caused by variations in wind speed, the power converter operation state is partitioned into different phases in terms of average wind speed and wind turbulence. Therefore, the contributions can be considered separately. Then, in regards to the reliability assessment caused by short-term thermal cycling, the wind profile is converted to a wind speed distribution, and the contribution of different wind speeds to the final failure rate is accumulated. Finally, the reliability of an actual power converter semiconductor for a 2.5 MW wind turbine is assessed, and the failure rates induced by different timescale thermal behavior patterns are compared. The effects of various parameters such as cut-in, rated, cut-out wind speed on the failure rate of power devices are also analyzed based on the proposed model.

• Journal of Korea Game Society
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• v.15 no.4
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• pp.69-78
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• 2015

As the online game industry has been growing rapidly, more and more malicious activities to gain economic benefits have been reported as well. Game bot is one of the biggest problems in the online game industry. So we proposed a bot detection method based on the ERG theory of motivation for the first time. Most of the previous studies focused on behavior-based detection by monitoring patterns of the specific actions. In this paper, we applied the motivation theory to analyze user behaviors on a real game dataset. The result shows that normal users in the game followed the ERG theory of motivation in the same way as it works in real world. But in the case of game bots, the theory could not be applied because the game bot has specific reasons, unlike normal game users. We applied the ERG theory to users to distinguish game bot users from normal users. We detected the game bot with high accuracy of 99.78% by applying the theory.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.615-625
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• 2015

This paper proposes new methods and examples for improving fraud detection rules based on banking customer's transaction behaviors focused on anomaly detection method. This study investigates real example that FDS(Fraud Detection System) regards fraudulent transaction as legitimate transaction and figures out fraudulent types and transaction patterns. To understanding the cases that FDS regard legitimate transaction as fraudulent transaction, it investigates all transactions that requied additional authentications or outbound call. We infered additional facts to refine detection rules in progress of outbound calling and applied to existing detection rules to improve. The main results of this study is the following: (a) Type I error is decreased (b) Type II errors are also decreased. The major contribution of this paper is the improvement of effectiveness in detecting fraudulent transaction using transaction behaviors and providing a continuous method that elevate fraud detection rules.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.573-583
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• 2015

Amcache.hve file is a registry hive file regarding Program Compatibility Assistant, which stores the executed information of applications. With Amcache.hve file, We can know execution path, first executed time as well as deleted time. Since it checks both the first install time and deleted time, Amcache.hve file can be used to draw up the overall timeline of applications when used with the Prefetch files and Iconcache.db files. Amcache.hve file is also an important artifact to record the traces of anti-forensic programs, portable programs and external storage devices. This paper illustrates the features of Amcache.hve file and methods for utilization in digital forensics such as estimation of deleted time of applications.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.85-91
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• 2018

Most banks use only demographic information such as gender, age, occupation and address to segment customers, but they do not reflect financial behavior patterns of customers. In this study, we aim to solve the problems by using various big data in a bank and to develop customer segmentation method which can be widely used in many banks in the future. In this paper, we propose an approach of segmenting clustering blocks with bottom-up method. This method has an advantage that it can accurately reflect various financial needs of customers based on various transaction patterns, channel contact patterns, and existing demographic information. Based on this, we will develop various marketing models such as product recommendation, financial need rating calculation, and customer churn-out prediction based on this, and we will adapt this models for the marketing strategy of NH Bank.

• Journal of the Korea Convergence Society
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• v.8 no.6
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• pp.17-27
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• 2017

Recently, as cyber attacks have been activated, many such attacks have come into contact with various media. Research on security engineering and reverse engineering is active, but there is a lack of research that integrates them and applies attack systems through cost effective attack engineering. In this paper, security - enhanced information systems are developed by security engineering and reverse engineering is used to identify vulnerabilities. Using this vulnerability, we compare and analyze lifecycle models that construct or remodel attack system through attack engineering, and specify structure and behavior of each system, and propose more effective modeling. In addition, we extend the existing models and tools to propose graphical attack specification models that specify attack methods and scenarios in terms of models such as functional, static, and dynamic.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.2
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• pp.347-363
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• 2019

Malware has its own unique behavior characteristics, like DNA for living things. To respond APT (Advanced Persistent Threat) attacks in advance, it needs to extract behavioral characteristics from malware. To this end, it needs to do classification for each malware based on its behavioral similarity. In this paper, various similarity of Windows malware is estimated; and based on these similarity values, malware's family is predicted. The similarity measures used in this paper are as follows: 'TF-IDF cosine similarity', 'Nilsimsa similarity', 'malware function cosine similarity' and 'Jaccard similarity'. As a result, we find the prediction rate for each similarity measure is widely different. Although, there is no similarity measure which can be applied to malware classification with high accuracy, this result can be helpful to select a similarity measure to classify specific malware family.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.4
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• pp.89-100
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• 2011

Physical memory analysis has been an issue on a field of live forensic analysis in digital forensics until now. It is very useful to make the result of analysis more reliable, because record of user behavior and data can be founded on physical memory although process is hided. But most memory analysis focuses on windows based system. Because the diversity of target system to be analyzed rises up, it is very important to analyze physical memory based on other OS, not Windows. Mac OS X, has second market share in Operating System, is operated by loading kernel image to physical memory area. In this paper, We propose a methodology for physical memory analysis on Mac OS X using symbol information in kernel image, and acquire a process information, mounted device information, kernel information, kernel extensions(eg. KEXT) and system call entry for detecting system call hooking. In additional to the methodology, we prove that physical memory analysis is very useful though experimental study.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1101-1112
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• 2021

Organizations continue to increase investment in information security(IS) policies and technologies to prevent external intrusion and internal exposure to information assets. However, as the organization's regulations and behavioral requirements for strict IS policy increase, employees may induce negative behaviors through IS-related stress. The purpose of this study is to suggest the effects of challenge and hindrance stressors on IS compliance intentions and to confirm how authentic leadership moderates the positive and negative effects of stressors. We reflected employees of the organization who are applying IS policy to their work as a study target and applied a survey to obtain a sample for research hypothesis verification. As a result of analysis through structural equation modeling, challenge and hindrance stressors affected IS compliance intentions, and authentic leadership moderated the effects of stressors on compliance intention. Our research helps to establish insiders support strategies to achieve internal IS goals, because the results suggested stressor conditions and leaders' behavioral directions that influence employees IS compliance behavior.