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사례 위주로 본 공급자망을 중심으로 한 IT제품 보안 위험
최웅철,Choi, Woongchul 디지털산업정보학회 2016 디지털산업정보학회논문지 Vol.12 No.4
Before an IT product is used, there is a sequence of the process such as the components supply-demand of the product, their assembly and production, their logistics and delivery, and then finally, the product can be used by a user. During this sequence of the process, there can be many security exposures and risks. In this paper, we show, by examining security cases of various IT products, that there are many security exposures in the process of IT products from their production to their delivery to end users and in their use, and also show how critical the security exposures are. Even though there are various security theories, technologies and security controls, there is still weak link from the production of an IT product to its use, and this weak link can lead to security vulnerabilities and risks. This paper tries to call attention to the importance of the execution of the security control and the control components. We examine the practical cases to find out how the security control is paralyzed, and to show how it is compromised by asymmetric security resources. Lastly, from the cases, we examine and review the possible domestic security issues and their countermeasures.
VoIP 스니핑을 통한 특정정보 탈취 위험성에 관한 연구
이동건,최웅철,Lee, Donggeon,Choi, Woongchul 디지털산업정보학회 2018 디지털산업정보학회논문지 Vol.14 No.4
Recently, VoIP technology is widely used in our daily life. Even VoIP has become a technology that can be easily accessed from services such as home phone as well as KakaoTalk.[1] Most of these Internet telephones use the RTP protocol. However, there is a vulnerability that the audio data of users can be intercepted through packet sniffing in the RTP protocol. So we want to create a tool to check the security level of a VoIP network using the RTP protocol. To do so, we capture data packet from and to these VoIP networks. For this purpose, we first configure a virtual VoIP network using Raspberry Pi and show the security vulnerability by applying our developed sniffing tool to the VoIP network. We will then analyze the captured packets and extract meaningful information from the analyzed data using the Google Speech API. Finally, we will address the causes of these vulnerabilities and possible solutions to address them.
Chulyoung Choi(최철영),Woongchul Choi(최웅철) 대한전기학회 2017 전기학회논문지 Vol.66 No.12
Global automobile manufacturers are developing electric vehicles (EVs) to eliminate the pollutant emissions from internal combustion vehicles and to minimize fossil fuel consumptions for the future generations. However, EVs have a disadvantage of shorter traveling distance than that of conventional vehicles. To answer this shortfall, more batteries are installed in the EV to satisfy the consumer expectation for the driving range. However, as the energy capacity of the battery mounted in the EV increases, the amount of heat generated by each cell also increases. Naturally, a better battery thermal management system (BTMS) is required to control the temperature of the cells efficiently because the appropriate thermal environment of the cells greatly affects the power output from the battery pack. Typically, the BTMS is divided into an active and a passive system depending on the energy usage of the thermal management system. Heat exchange materials usually include gas and liquid, semiconductor devices and phase change material (PCM). In this study, an application of PCM for a BTMS was investigated to maintain an optimal battery operating temperature range by utilizing characteristics of a PCM, which can accumulate large amounts of latent heat. The system was modeled using Dymola from Dassault Systems, a multi-physics simulation tool. In order to compare the relative performance, the BTMS with the PCM and without the PCM were modeled and the same battery charge/discharge scenarios were simulated. Number of analysis were conducted to compare the battery cooling performance between the model with the aluminum case and PCM and the model with the aluminum case only.
IEEE 802.15.3 Wireless PAN의 MAC에서 다중채널의 적용
이병주,이승형,최웅철,정광수,이장연,조진웅,Lee Byung-Joo,Rhee Seung Hyong,Choi WoongChul,Chung Kwangsue,Lee Jang-Yeol,Cho Jin-Woong 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.8A
본 논문에서는 IEEE 802.15.3 High-Rate WPAN (Wireless Personal Area Network) 환경에서 다중 채널을 사용하여 향상된 성능의 MAC 프로토콜을 제안한다. IEEE 802.15.3 High-Rate WPAN은 10m 내외의 거리에서 실시간 비디오 및 대용량 파일 전송을 목적으로 설계된 MAC과 PHY의 표준을 말한다. 현재 표준의 MAC 프로토콜은 하나의 무선 채널을 piconet 내의 모든 DEV가 공유하여 사용한다. 이 중 PNC(Piconet Coordinator)는 TDMA(Time Division Multiple Access)방식으로 DEV들에게 채널타임을 할당한다. 이런 경우 piconet내의 통신하는 DEV의 수가 많아지게 되면 superframe의 길이가 길어져 전송되는 데이터의 aggregate throughput이 떨어지고 QoS(Quality of Service)를 보장하지 못한다. 본 논문에서 하나의 piconet이 여러 개의 채널을 동시에 사용하여 aggregate throughput을 향상시키고 QoS를 보장하는 다중채널 MAC 프로토콜을 제안하고 시뮬레이션을 통해 향상된 성능을 증명한다. This paper presents a multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN (Wireless Personal Area Network). The current MAC protocol of the IEEE 802.15.3 High-rate WPAN is designed for sharing a single channel among DEVs of a piconet; that is, within a single piconet, PNC prevents interference through MAC layer assignment of time slots to other DEVs using time-division multiple access. When the number of DEVs that communicate with each other frequently, is increased in a single WPAN, the size of the superframe becomes inevitably large, and this may result in a significant throughput drop or a failure to provide QoS guarantee. A multi-channel enhancement scheme for the MAC protocol of IEEE 802.15.3 High-rate WPAN is proposed to significantly increase the aguegate throughput and more reliably provide the QoS guarantees in a piconet