• 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 the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.1-5
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• 2011

We present the implementation of MAC system for MBOA UWB SoC. The implemented MBOA MAC algorithm is not master control mechanism, but distributed network mechanism. Therefore, mesh network can be easily constructed because MAC consists of distributed network and administrates network. The ARM926EJ with cache is adopted for high performnace and AMBA bus is applied for system design and reuse. In addition, the system operating clock management algorithm is implemented for low power consumption. The dedicated DMA for MAC is designed between the system memory buffer and MAC hardware, and the dedicated DMA for USB 2.0 is also implemented between system memory buffer and host for high data transaction.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.618-622
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• 1990

In this study LLC and MAC program, which is the base of the communication software, is implemented. This program is tested in the MAP board for IBM PC. The LLC is of class 3, which provides the services of type 1 and 3. The MAC uses the Token Passing Bus Access Method of IEEE 802.4 standard. The LLC is implemented in C language, and MAC in C language and 80186 assembly language. MAC program takes advantage of MC 68824 which is the token bus controller produced by Motorola.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.95-105
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• 2010

IEEE 802.15.4 is the one of the protocols for radio communication in a personal area network. Since it aims to provide low cost and low power communication for ubiquitous communication, it requires high level of optimization in implementation. Recently, there have been many studies on the performance evaluation of IEEE 802.15.4 MAC protocol. According to the results of the studies, it is tendency that the transceiver is implemented to SoC type. On the implementation, the specific functions of MAC like CSMA-CA and MAC frame handling is designed to hardwired functions. In this paper, we implemented the protocol with hardwired low MAC (HL-MAC) and its state machine for the optimization from the physical layer and MAC layer. it has the characteristics of the small code size and the enhanced power consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1C
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• pp.54-62
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• 2012

A Wi-Fi mesh network providing multi-hop wireless connections based on IEEE 802.11 PHY/MAC technology has recently received a significant attention as a network infrastructure that interconnects RFID systems and wireless sensor networks (WSNs). However, the current IEEE 802.11 contention-based MAC protocol cannot fully utilize the network capacity due to eithor frame collisions or unused network resources. In this paper, we propose a novel multi-channel scheduling MAC (MCS-MAC) protocol for Wi-Fi mesh networks. Under the secondary interference model of Wi-Fi mesh networks, the MCS-MAC protocol can maximize the network throughput via activation of collision-free links that has a maximal link weight. Through the simulations, we show that the throughput of the MCS-MAC protocol is at least three times higher than that of existing MAC protocols in Wi-Fi mesh networks.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.837-844
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• 2019

In this paper, we propose the AMBM(: Adaptive Multi-channel Backoff Machisum) -Mac protocol to provide high throughput for non-safety applications in VANET(: Vehicular Ad Hoc Networks) environment. The proposed protocol guarantees the quality of service of non-safety packets by dynamically adjusting CW(: Channel Window) of WSA(: WAVE Service Advertisement) to maximize throughput between non-safety packets of different priority. It also shows that allocating a large amount of time for channel coordination and time slot reservation for SC and dynamically adjusting CW and CCI as nodes increase to reduces transmission delay than IEEE 1609.9, C-MAC(: Coordinated multi-channel MAC, and Q-VCI(: QoS Variable CCH Interval) protocols.

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.283-289
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• 2002

The effects of electroacupuncture (EA) at SP-6 with different durations on the minimum alveolar concentration (MAC) and on the cardiovascular system were evaluated in dogs under isoflurane anesthesia. Eight healthy male beagles were randomly assigned to four study groups (n = 5/group) with washout period of 7 days for recovery and anesthetic withdrawal between experiments. Four study groups were control, nonacupoint electrical stimulation (NA), EA for 30 minutes (SP-6) and continuous EA for 70 or 90 minutes (SP-6C). For the nonacupoint electrical stimulation group, needles were inserted into the nonacupoint at the muscle bellies of left triceps brachii and right quadriceps femoris. MAC and cardiovascular parameters were determined after EA at SP-6 acupoint and at nonacupoint. Thirty minutes of EA and continuous EA until re-determination of MAC at SP-6 acupoint lowered the MAC of isoflurane by 21.3$\pm$8.0% and 16.1$\pm$4.6%, respectively (p<0.05). The decrements in MAC values were not significantly different between two EA groups. However, electrical stimulation of nonacupoint did not induce a significant change in MAC. In SP-6 and SP-6C groups, significant changes in cardiovascular parameters were not observed. These results indicate that EA at SP-6 have an advantage in isoflurane anesthesia in terms of reducing the requirement for anesthetics and minimizing cardiovascular side effects. EA for 30 minutes at maximum might be the sufficient time to produce acupuncture analgesia.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.349-352
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• 2000

In this paper, a SIMD 64bit MAC (Multiply -Accumulate) unit is designed. It is composed of two 32bit MAC unit which supports SIMD 16bit operations. As a result, It can process two 32bit MAC operations or four 16bit operations in one cycle. Proposed MAC unit is described in Verilog HDL. After functional verification is performed, MAC unit is synthesized and optimized with 0.35$\mu\textrm{m}$ standard cell library. The synthesis result shows that this MAC unit can operate at 80㎒ of clock frequency in 85$^{\circ}C$, 3.0V, worst case process and 125㎒ of clock frequency at 25$^{\circ}C$, 3.3V, typical case process. It achieves 320Mops of performance, and is suitable for embedded DSP processors.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1414-1417
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• 2010

고정된 duty-cycle을 갖는 S-MAC 프로토콜은 노드 A에서 B로 메시지를 전송 후, 노드 C는 에너지 효율을 위해 스케줄 된 수면구간 상태이다. 따라서 노드 C는 노드 B로부터의 메시지를 수신 할 수가 없게 된다. 따라서 지연(delay)이 발생하게 된다. 반면 제안하는 프로토콜은 평상시에 Bit정보가 00으로 설정되어 있어, 에너지 효율에 중점을 둔 S-MAC과 비슷한 동작을 하다가 설정한 설정치를 넘길 때마다 Bit정보에 변화를 주어 전송해야 할 메시지의 우선순위가 높다고 판단하여 프레임크기와 활성구간의 크기에 변화를 주어 지연시간을 줄이게 된다. 사용자 입장에서 우선순위가 높은 메시지라 함은 예를 들어 불이 발생 했을 경우 노드에서 감지되는 높은 온도 값이 이에 해당되고 반면 우선순위가 낮은 메시지는 노드에서 감지되는 낮은 온도 값이 이에 해당된다. 사용자 입장에서 감시해야 할 온도, 압력, 수위와 같은 환경변수에 설정치를 설정하여 상황에 따라 지연시간과 에너지 소모를 선택적으로 유연하게 조절하여 지연시간을 개선시키는 MAC 프로토콜을 제안한다.

• The KIPS Transactions:PartC
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• v.19C no.3
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• pp.173-178
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• 2012

Recent two security schemes showed that a bloom filter can reduce a message length required for representing multiple MACs. The schemes, however, made message length comparison without considering security level. Since the MAC is intended for security, it is important to let multiple MACs and the bloom filter have the same level of security for making message length comparison. In this paper, we analyze the message length efficiency of bloom filter, compressed bloom filter and multiple MACs, letting them have the same security level.