• Annual Conference of KIPS
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• 2002.11c
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• pp.1973-1976
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• 2002

본 논문에서는 유 무선 네트워크 환경에서의 자료 일치성 유지를 위한 동기화 프로토콜(SyncML1.1)을 검증한다. 프로토콜 검증에 관한 기존 연구에서는 약한 일관성을 갖는 동기화 프로토콜은 다루어지지 않았으며 정리 증명 혹은 모델 채킹에 대한 선택적 접근으로인해 증명 영역이 제한적이었다. 본 연구에서는 프로토콜의 의미를 정의하고 행위 및 시스템 구조, 메시지 패싱에 대한 개별적 모델을 단계적으로 설계하는 한편, 동기화 프로토콜에서의 안전성 및 상호 배제, 궁극성 속성은 시퀀트 계산법에서의 역방향 전략으로 증명되며, 모델 채킹 기술을 하나의 증명 규칙으로 사용했다. 본 연구는 두가지 부분에서 특징과 의미을 갖는다. 첫째, 정리증명과 모델 채킹이 혼합된 검증 방법을 사용했다. 둘째, 객체 제약 언어 및 정형 명세 언어의 사용을 통해 모델의 생성을 보다 단계적이고 정형적으로 유도했으며 이를 통해 검증의 신뢰성 및 품질을 높였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.25-34
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• 2006

In this paper DynaMoNET is suggested as a novel IPv6-based multi-homed mobile network architecture which is composed of nested mobile ad hoc networks dynamically coming together through wireless personal area networks. Each ad hoc network has a mobile router which may work as a root mobile router instead of fixed mobile routers in a DynaMoNET. A root mobile router provides the reliable Internet connectivity for the entire mobile network. This paper includes a innovative handover protocol for multi-homed mobile networks, network switchover algorithm considering multiple decision factors, root mobile router election process based on token-based algorithm fast root mobile router discovery algorithm and fault avoidance mechanism to support reliable Internet connectivity. Finally the system architecture of a mobile router is given in detail.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.1023-1031
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• 2010

With recent advances in hardware and wireless communication techniques, wireless multimedia sensor network which collects multimedia data through wireless sensor network has started to receive a lot of attentions from many researchers. Wireless multimedia sensor network requires a research of efficient compression and transmission to process the multimedia data which has large size, in the wireless sensor network that has very low network bandwidth. In this paper, we propose PIT protocol for the transmission based on the priority that classified by the DPCM compression. The PIT protocol sets different priority to the each subbands which are divided by the wavelet transform. The PIT protocol transmits the data with higher priority to guarantee the high image quality. The PIT protocol uses the characteristic of wavelet transform that the transformed image is very insensible to the data loss. In PIT protocol, each subbands of wavelet transformed image has fair weight in the compressed image to utilize the prioriy based transmission. The experiment results show that the PIT protocol improves the quality of image in spite of data loss.

• Annual Conference of KIPS
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• 2012.11a
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• pp.1080-1083
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• 2012

최근 많은 스마트 디바이스의 보급으로 언제 어디서든지 모바일 네트워크를 통해 인터넷을 사용할 수 있게 되었으며, 단말이 가지는 자원 및 컴퓨팅 파워의 한계에 따라 모바일 클라우드 서비스에 대한 관심이 폭발적으로 증가하고 있다. 하지만 모바일 클라우드 서비스는 그 환경에 따라 사용자 단말에서 나타나는 보안위협과 클라우드 환경에서의 보안위협이 복합적으로 나타나게 된다. 모바일 클라우드 환경에서의 보안위협 중 사용자 단말 영역에서의 키로깅 공격으로부터 사용자 입력정보를 보호하기 위한 기존의 가상키보드를 비교 분석하였다. 본 논문에서는 기존에 사용되고 있는 가상키보드의 확률적 분석을 통한 키 유추 가능성을 보완하기 위해 보안성이 강화된 새로운 형태의 가상키보드를 제안한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.2
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• pp.213-225
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• 2022

Containerization, a lightweight virtualization technology, enables agile deployments of enterprise-scale microservices in modern cloud environments. However, containerization also opens a new window for adversaries who aim to disrupt the cloud environments. Since microservices are composed of multiple containers connected through a virtual network, a single compromised container can carry out network-level attacks to hijack its neighboring containers. While existing solutions protect containers against such attacks by using network access controls, they still have severe limitations in terms of performance. More specifically, they significantly degrade network performance when processing packet payloads for L7 access controls (e.g., HTTP). To address this problem, we present BPFast, an eBPF/XDP-based payload inspection system for containers. BPFast inspects headers and payloads of packets at a kernel-level without any user-level components. We evaluate a prototype of BPFast on a Kubernetes environment. Our results show that BPFast outperforms state-of-the-art solutions by up to 7x in network latency and throughput.

• Journal of Korea Multimedia Society
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• v.7 no.4
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• pp.550-558
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• 2004

Previous researches on scalability problem of distributed virtual environment (DVE) have been mainly focused on spatial partitioning of area of interest (AOI). Congestion phenomena by avatar groups in AOI have been neglected relatively However, AOI congestion is highly related to scalability of DVE because it exhausts system resources such as network bandwidth and rendering time, and could be a bar to perform collaboration among participants. In this paper, this will be defined as the problem that must be solved for the realization of the scalable DVE, and a model will be proposed to measure and control congestion situation in AOI. The purposes of the proposed model are to prevent high density of participants in AOI, and to protect stable collaboration in DVE. For evaluation of the performance it is compared with a previous method by defining the resource cost model which is dynamically activated to AOI congestion.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.10-13
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• 2009

본 논문에서는 모드해석 기법이 내장된 가속도기반 무선센서노드을 개발하였다. 이를 위해 다음과 같은 연구가 수행되었다. 첫째, 가속도 데이터를 취득하고 분석할 수 있는 가속도기반 무선센서노드를 설계하였다. 둘째, 무선센서노드를 이용한 구조건전성모니터링에 적합한 모드해석 기법으로 주파수영역분해법을 선정하였다. 셋째, 무선센서노드에서 모드해석을 독자적으로 수행하기 위한 분산 무선센서 네트워크기반 모드해석 알고리즘을 설계하고 무선센서노드에 내장하였다. 마지막으로, 개발된 무선센서노드를 PSC 거더모형에 설치하고 기존 구조건전성모니터링 시스템과의 성능비교를 통해 검증하였다.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.107-112
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• 2003

2003년 1월 25일의 인터넷 침해사고는 정보통신망의 중요성을 실감하게 해준 사건이다. 이 사건의 원인을 여러 가지로 말할 수 있지만, 가장 근본적인 원인은 소프트웨어의 취약점에 대한 관리가 부재한 것이었다. 소프트웨어가 특정 취약점을 갖게되는 데에는 다양한 원인이 존재하며 이에 대한 연구는 폭넓게 진행되어 왔다. 본 논문은 이러한 연구들을 기반으로 취약성을 모델링하는 방법에 대해서 다루고자 한다. 특히, 단위 취약점 개념을 사용한 취약성의 시스템적인 분석 방법을 설명하고, 이러한 개념이 생존성 평가에 어떻게 활용될 수 있는지를 다루고자 한다. 본 논문의 연구 결과는 기존의 취약성 분석 기법을 좀더 정형화 해주는 역할을 할뿐만 아니라, 정보보호 영역에 시뮬레이션 기술을 어떻게 활용할 수 있는지에 대한 하나의 방법으로 활용될 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.184-194
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• 2011

Security is critically important for smart grid networks that are usually used for the electric power network and IT environments that are opened to attacks, such as, eavesdropping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for smart grid networks. ZigBee is used for low data rate and low power wireless network applications. To deploy smart grid networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.

• Journal of The Korean Association For Science Education
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• v.34 no.6
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• pp.571-581
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• 2014

This study aims to investigate how high school teachers and students perceive the purpose of science learning. Participants were high school science teachers and students from one hundred and sixty high schools nationwide, which were selected through proportional stratified sampling method. Teachers and students responded on open-ended questionnaires about the purpose of science learning. The data were analyzed using the semantic network analysis method. Our study illustrates three major finding: First, teachers recognized the intrinsic value related to cognitive domain as the more important purpose of science learning, while students recognized the extrinsic value related to personal usefulness domain as more important. Second, teachers' responses were significantly different depending on the teaching career. Beginning teachers believed both intrinsic and extrinsic values were equally important, while experienced teachers believed the cognitive domain about understanding of scientific knowledge was more important than intrinsic values. In other words, the differences in perception of the purpose of science between teachers and students, the experienced teachers is greater than the beginning teachers. Finally, students' responses were different depending on their academic track. Humanity major students recognized that learning science made their everyday-life easier while science major students recognized that learning science should be related to their future careers. In conclusion, the results of this study is expected to be of use as the basic data to identify the characteristic of teachers and students related to science.