• Annual Conference of KIPS
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• 2017.04a
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• pp.250-253
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• 2017

최근 모바일 결제 시장의 규모가 2015년 45억 달러에서, 2016년 62억 달러로 성장하며, P2P 거래량도 함께 증가하고 있다. 또한, P2P 결제 시장에 페이팔, 비자와 같은 온라인 결제 업체와 대형은행 뿐만 아니라, 페이스북, 구글, 애플, 삼성 등 IT회사들도 참여하고 있다. 안전하고 편리한 P2P 결제를 위해 다양한 거래 방식이 연구되고 있지만, 다양한 기업 및 은행들의 참여로 인해 서로 다른 방식으로 사용자들이 불편을 겪고 있으며, 모바일 환경의 특성으로 인해 많은 보안위협들이 발생하고 있는 실정이다. 이에 따라, 모바일 환경에서의 P2P 결제를 고려한 통합적인 보안 기술이 개발되어야 하며, 민감 정보라고 할 수 있는 사용자의 계좌번호, 금융거래 관련 정보 등을 보호하기 위한 기술이 필수적이다. 따라서 기존 은행권의 P2P 거래 방법의 문제점을 분석하고 블록체인 시스템과 DHT에 대해 분석한 후, P2P 결제 환경에 적합한 안전한 블록체인 기반 금융 거래 시스템을 연구함으로써, P2P 거래 환경의 안전성을 향상시키고자 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.466-469
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• 2018

최근 PC를 비롯한 모바일, IOT 기기 등 다양한 환경에서의 사이버 공격이 기승을 부리고 있으며, 그 방법 또한 나날이 발전하고 있다. 이러한 사이버위협으로부터 개인 및 기업의 자산을 지키기 위한 근본적인 대안이 없이는 매번 반복적인 피해를 피하기 어려운 현실이다. 다양한 환경이라고 함은, 다양한 OS(Operation System), 다양한 ISA (Instruction Set Architecture)의 조합으로 이루어지는 사이버환경을 의미한다. 이러한 조합들은 일반 사용자들에게 가장 많이 쓰이는 Windows & Intel 조합의 환경과, Linux & Intel 또는 Linux & ARM 등 기업에서 서비스를 위해 쓰이는 서버 환경 등을 예로 들 수 있다. 그밖에 최근 IOT기기나 모바일 기기와 같은 환경도 있을 수 있다. 바이너리 파일에 대한 보안은 다양한 연구가 진행되고 있지만 그 범위가 방대하고, 깊이가 필요한 영역이라 진입 장벽이 높은 실정이다. 본 논문에서는 이러한 바이너리의 취약점을 분석하기 위한 첫 번째 단계로써 다양한 바이너리 파일을 하나의 정형화된 자료구조로 변환하는 바이너리 포맷 분석기의 한 방법을 제시하고자 한다. 다양한 OS와 다양한 ISA환경에서 사용되는 바이너리들에서 공통적으로 존재하는 정보들 중, 바이너리의 취약점 분석을 위해 필요한 데이터를 보다 효율적으로 수집하고, 관리하는 것이 바이너리를 통한 사이버 위협을 탐지하는 연구에서 기초가 된다고 할 수 있기 때문이다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.659-665
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• 2023

The exciter of a ship generator adjusts the magnetic flux through excitation current control to maintain the output terminal voltage constant. The voltage controller inside the exciter typically uses a proportional integral control method. however, the response characteristics determined by the gain and time constant produce unwanted output owing to an inappropriate setting value that can reduce the quality and stability of power within the ship. In this study, a neural network circuit is learned using stable input/output data that can be obtained through the AC4A type exciter model provided by IEEE, and the simulation is performed by replacing the existing proportional integral control type voltage controller with the learned neural network circuit controller. Consequently, overshooting was improved by up to 9.63% compared with that of the previous model, and excellence in stable response characteristics was confirmed.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.11-18
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• 2016

Accessing unauthorized rogue APs in WiFi environments is a very dangerous behavior which may lead WiFi users to be exposed to the various cyber attacks such as sniffing, phishing, and pharming attacks. Therefore, prompt and precise detection of rogue APs and properly alarming to the corresponding users has become one of most essential requirements for the WiFi security. This paper proposes a new rogue AP detection method which is mainly using the installation information of authorized APs and the DHCP snooping information of the corresponding switches. The proposed method detects rogue APs promptly and precisely, and notify in realtime to the corresponding users. Since the proposed method is simple and does not require any special devices, it is very cost-effective comparing to the wireless intrusion prevention systems which are normally based on a number of detection sensors and servers. And it is highly precise and prompt in rogue AP detection and flexible in deployment comparing to the existing rogue AP detection methods based on the timing information, location information, and white list information.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.807-808
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• 2016

With the recent rise in nuclear families and single-member families, there is a need for the kind of home management unaffected by neither space nor time. Moreover, electronic devices in and around the home need to be managed efficiently and prevented from overheating, and there is an increasing risk of fire, theft, and leak of personal data with these devices, which is leading to an increase in the economic costs. Accordingly, there is a growing need for an efficient and secure smart home management system. This paper proposes a home management system that uses smart devices. This system has addressed the shortcomings of a conventional Internet-based home network. Furthermore, it communicates with IoT-enabled devices and features intelligent information home appliances that are isolated from personally identifiable information and which are secure against advanced persistent threats, a type of cyber-attack.

• New & Renewable Energy
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• v.18 no.2
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• pp.73-81
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• 2022

This study was aimed at designing a condenser, as a component of the organic Rankine cycle system for ships. The condenser was manufactured through press molding to achieve a bent shape to enhance the heat transfer performance, considering the shape of the heat transfer plate used in a brazing plate heat exchanger. The heat transfer plate was made of copper-nickel alloy. The required heat transfer rate for the condenser was 110 kW, and the maximum number of layers was set as 25, considering the characteristics of high-temperature brazing. Computational fluid dynamics techniques were used to perform the thermal fluid analysis, based on the ANSYS CFX (v.18.1) commercial program. The heat transfer rate of the condenser was 4.96 kW for one layer (width and length of 0.224 and 0.7 m, respectively) of the heat transfer exchanger. The fin efficiency pertaining to the heat transfer plate was approximately 20%. The heat flow analysis for one layer of the heat exchanger plate indicated that the condenser with 25 layers of heat transfer plates could achieve a heat transfer rate of 110 kW.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.375-378
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• 2014

Marine disaster, such as 'the sinking of the Sewol ferry', on the ocean needs emergency communication with land post and Rescue services. Especially, It needs of emergency comomunication system has increased in Korea peninsula with the sea on three side. The system will be more fully equipped to deal with disasters linked to communication so alone sailing ship is at sea. Research is needed on communication links to submarines operated by submarine to sink a ship, as well as immersion in the sea with. And it is necessary in the study of the land in preparation for the emergency disaster ship and submarine communication links for offshore and subsea oil and associated communication systems. Will be studied in preparation for the communication protocols and emergency and disaster location and land the plane or for a career in the satellite systems are linked through this. It is necessary for this purpose is research on the integrated emergency disaster communication ecosystem.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.99-105
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• 2015

As increasing the use of smart phones, the interest of iOS and Android operating system is growing up. In this paper, a novel steganographic method based on Android platform is proposed. Firstly, we analyze the skia based image format that is supporting 2D graphic libraries in Android operating system. Then, we propose a new data hiding method based on the Android bitmap image format. The proposed method hides the secret data on the four true color areas which include Alpha, Red, Green, Blue. In especial, we increase the embedding capacity of the secret data on the Alpha area with a less image distortion. The experimental results show that the proposed method has a higher embedding capacity and less distortion by changing the size of the secret bits on the Alpha area.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.10
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• pp.1311-1319
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• 2019

Currently, the web environment is a commonly used area for sharing information and conducting business. It is becoming an attack point for external hacking targeting on personal information leakage or system failure. Conventional signature-based detection is used in cyber threat but signature-based detection has a limitation that it is difficult to detect the pattern when it is changed like polymorphism. In particular, injection attack is known to the most critical security risks based on web vulnerabilities and various variants are possible at any time. In this paper, we propose a novelty detection technique to detect abnormal state that deviates from the normal state on web-server log dataset(WSLD). The proposed method is a machine learning-based technique to detect a minor anomalous data that tends to be different from a large number of normal data after replacing strings in web-server log dataset with vectors using machine learning-based embedding algorithm.

• Journal of Internet Computing and Services
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• v.22 no.3
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• pp.45-52
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• 2021

Although many studies have been conducted to identify unknown attacks in cyber security intrusion detection systems, studies based on outliers are attracting attention. Accordingly, we identify outliers by defining categories for unknown attacks. The unknown attacks were investigated in two categories: first, there are factors that generate variant attacks, and second, studies that classify them into new types. We have conducted outlier studies that can identify similar data, such as variants, in the category of studies that generate variant attacks. The big problem of identifying anomalies in the intrusion detection system is that normal and aggressive behavior share the same space. For this, we applied a technique that can be divided into clear types for normal and attack by discrete wavelet transformation and detected anomalies. As a result, we confirmed that the outliers can be identified through One-Class SVM in the data reconstructed by discrete wavelet transform.