• Journal of Communications and Networks
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• v.18 no.5
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• pp.857-869
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• 2016

This paper proposes an X-MAC/BEB protocol that runs a binary exponential backoff (BEB) algorithm on top of an X-MAC protocol to save more energy by reducing collision, especially in densely populated wireless sensor networks (WSNs). X-MAC, a lightweight asynchronous duty cycle medium access control (MAC) protocol, was introduced for spending less energy than its predecessor, B-MAC. One of X-MAC 's conspicuous technique is a mechanism to allow senders to promptly send their data when their receivers wake up. X-MAC, however, has no mechanism to deal with sudden traffic fluctuations that often occur whenever closely located nodes simultaneously diffuse their sense data. To precisely evaluate the impact of the BEB algorithm on X-MAC, this paper builds an analytical model of X-MAC/BEB that integrates the BEB model with the X-MAC model. The analytical and simulation results confirmed that X-MAC/BEB outperformed X-MAC in terms of throughput, delay, and energy consumption, especially in congested WSNs.

• The KIPS Transactions:PartC
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• v.17C no.4
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• pp.335-346
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• 2010

Mac OS X is the Computer Operating System that develop in Apple Inc. Mac OS X is the successor to Mac OS 9 Version which had been Apple's primary operating system since 1984. Recently, Mac OS X 10.6 (Snow Leopard) has been manufactured and is distributed to user. Apple's Mac OS X Operating System is occupying about 10% in the world Operating System market share. But, Forensic tools that is utilized on digital forensic investigation can not forensic analysis about Mac OS X properly. To do forensic investigation about Mac OS X, information connected with user's action and trace can become important digital evidence in Operating System. This paper presents way about user trace data acquisition methodology in Mac OS X.

• Journal of IKEEE
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• v.16 no.2
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• pp.86-94
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• 2012

Synchronization MAC Protocol such as S-MAC and T-MAC utilize duty cycling technique which peroidically operate wake-up and sleep state for reducing energy consumption. But synchronization MAC showed low energy efficiency because of additional control packets. For better energy consumption, Asychronization MAC protocols are suggested. For example, B-MAC, and X-MAC protocol adopt Low Power Listening (LPL) technique with CSMA algorithm. All nodes in these protocols joining a network with independent duty cycle schedules without additional synchronization control packets. For this reason, asynchronous MAC protocol improve energy efficiency. In this study, a low-power MAC protocol which is based on X-MAC protocol for wireless sensor network is proposed for better energy efficiency. For this protocol, we suggest preamble numbering, and virtual-synchronization technique between sender and receive node. Using TelosB mote for evaluate energy efficiency.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.69-77
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• 2008

I propose adding users’Media Access Control (MAC) addresses to standard X.509 certificates to provide more secure authentication. The MAC address can be added by the issuing Certification Authority (CA) to the "extensions" section of the X.509 certificate. I demonstrate that when two users with MAC address information on their digital certificates communicate, the MAC address on the first user’s certificate can be easily verified by the second user. In this way, security can be improved without markedly degrading system performance and the level of initial trust between participants in virtual communities will be improved.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.846-849
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• 2011

최근 iPhone, iPad의 높은 사용율과 더불어 Apple 의 Mac 계열 제품에 대한 관심도 높아지고 있다. 이는 Apple의 운영체제인 Mac OS X의 사용율 증가와 함께 디지털 포렌식 수사 환경에서의 Mac OS X의 중요성이 높아짐을 의미한다. 디지털 포렌식 관점에서 Mac OS X에는 사용자의 사용 정보를 남기는 주요 Artifacts들이 있다. 외부 저장 장치 연결 정보, 어플리케이션 설치 정보, 사용자 인증 정보, 어플리케이션 설정 정보 등이 대표적인 Artifacts들이며, 이러한 정보들은 특정 위치의 로그 파일에 남게 된다. 본 논문은 Mac OS X의 대표적 Artifacts 들을 대상으로 사용 흔적 정보가 남는 파일을 분석하여 디지털 포렌식 수사 시 활용할 수 있도록 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.762-770
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• 2010

The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.12
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• pp.873-875
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• 2014

In this paper we describe an asynchronous MAC protocol with receiver-initiated duty cycling for energy-efficiency in wireless sensor networks(WSN). Legacy asynchronous MAC protocols, X-MAC and PW-MAC, has weaknesses which generates too many control packets and has data collision problem between multiple transmitters, respectively. Therefore, we propose a receiver-initiated asynchronous MAC protocol which generates control packets from transmitter to complement these disadvantages. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a improvement in energy-efficiency, throughput and latency from simulation results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2638-2647
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• 2010

X-MAC reduces transmission delay and energy consumption by using a short preamble instead of the existing long preamble. To solve the problem of X-MAC, this paper proposes a new MAC protocol called Express-MAC. The wireless sensor network is mainly used for the purpose of gathering event data or situation information. Especially, the transmission pattern of the sensor network with the purpose of event detection such as intrusion detection is very intermittent as well as successively occurring when a single event takes place in most cases. By reflecting sensor network's key transmission patterns as above, EX-MAC has used multi-hub path's path reservation system and awake section's transmission time reservation method in data transmission when the first event takes place. The awake time reservation in transmission path has improved successive data transmission's end-to-end delay, and it has also increased efficiency in terms of energy consumption by reducing the preamble length of data transmission and reception node.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1604-1617
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• 2014

This paper proposes RIX-MAC (Receiver-Initiated X-MAC), a new energy-efficient MAC protocol based on an asynchronous duty cycling. RIX-MAC improves energy efficiency through utilizing short preambles and adopting the receiver-initiated approach, where RIX-MAC minimizes sender nodes' energy consumption by enabling transmitters to predict receiver nodes' wake-up times. It also reduces receiver nodes' energy consumption by decreasing the number of control frames. We use the network simulator to evaluate RIX-MAC's performance. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a remarkable improvement in energy-efficiency and end-to-end delay.

• 프린팅코리아
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• s.35
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• pp.162-165
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• 2005

지난 4월12일 인큐브테크가 Quark 6.5v을 발표했고 이 달 중순경 Mac OS X 10.4 'Tiger' 버전이 출시된다. 지난해 하반기에는 본체와 모니터가 결합된 일체형 컴퓨터 ‘G5'가 모습을 드러냈고 본격적인 시판에 들어갔다. 물론 이들은 Mac OS X에 맞춰 출시됐다. 이미 하드.소프트웨어가 호환성을 바탕으로 한 제 모습을 통해 동시에 움직이고 있는 것이다. 2000년대 초반까지 OS 9가 주축이 돼 있었지만 본격적인 OS X의 활약으로 점진적으로 축소될 것으로 보인다. 이는 바로 관련 S/W들이 이제는 선택에 의해 변화를 시도하는 차원이 아니라 필수 요소로 받아들이고 있는 것이다.