• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.39-47
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• 2005

This paper proposes and analyzes the MAC(Message Authentication Code) algorithm that is used for the transition integrity and the entity authentication of message. The MAC algorithm uses the DES algorithm which has 64-bit block and 56-bit key and we compare the security according to 64-bit and 32-bit length of MAC value. Moreover, we use the SEED algorithm which has 128-bit block and 128-bit key and compare the security according to 128-bit and 64-bit length of MAC value. We analyze the security the forgery attack according to length of message and length of MAC value. this paper, a coarse-to-fine optical flow detection method is proposed. Provided that optical flow gives reliable approximation to two-dimensional image motion, it can be used to recover the three-dimensional motion. but usually to get the reliable optical flows are difficult. The proposed algorithm uses Horn's algorithm (or detecting initial optical flow, then Thin Plate Spline is introduced to warp a image frame of the initial optical flow to the next image frame. The optical flow for the warped image frame is again used iteratively until the mean square error between two image sequence frames is lowered. The proposed method is experimented for the real moving Picture image sequence. The proposed algorithm gives dense optical flow vectors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1138-1146
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• 2006

It is very important for the sensor network to save battery capacity. Switching active mode to sleep mode is used for S-MAC protocol and expiring timer before end of the active part is used for T-MAC in order to extend battery life span. We proposed IS-MAC (Improved Sensor MAC) which gives more energy efficiency than S-MAC and T-MAC To improve energy efficiency in sensor network, we used the threshold value in buffer to transmit data packet and proposed the method to reduce the number of control packets which cause extra battery consumption. Based on the analytical results, we found that the proposed IS-MAC protocol shows better performance than conventional MAC protocols.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2705-2710
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• 2016

Recent evidence haas indicated that meningioma-associate protein (MAC30) exhibits different expression patterns in various tumors. However, little is known about the value of MAC30 in human squamous cell carcinoma of lung (SQCLC). The purpose of our study was to investigate the expression of MAC30 and to explore its clinical significance in SQCLC patients. A total of 156 Chinese patients diagnosed with SQCLC were selected for this study. The expression of MAC30 in all tissues was confirmed by immunohistochemical staining. Quantitative real-time PCR was performed to analyze MAC30 mRNA expression in 32 cases of SQCLC patients with corresponding non-tumor lung tissues. We observed enhanced mRNA expression of MAC30 in SQCLC as compared to control samples. Further, elevated MAC30 protein expression was strongly associated with poor tumor differentiation, TNM stage, and lymph node metastasis. In addition, we observed that patients with increased MAC30 expression demonstrated poor overall survival. Multivariate analysis explicated that increased MAC30 expression was a valuable independent predictable factor for poor tumor differentiation and short survival in SQCLC patients. Our present study suggests that MAC30 may serve as a biomarker for poor tumor differentiation and outcomes of patients with SQCLC.

• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.148-152
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• 2020

The quantitative accuracy of dry rehydratable film method was compared with the standard culture method to analyze the applicability of dry rehydratable film in the total aerobic bacteria test for water. The materials used in this study were 500 cases of water and were tested according to the Korean official test method for drinking water. The mean value of the total aerobic bacteria in plate count agar(PCA) and MC-Media Pad AC(MAC) were 2.6 ± 1.1 Log cfu/mL and 2.6 ± 1.2 Log cfu/mL. The p value and correlation coefficient(R²) were 0.933 and 0.9985 between the PCA and MAC, respectively, indicating no significant difference and very high correlation. According to the water types, the p value and R² were 0.887 and 0.9911 in the PCA and MAC. In the purified water, the p value was 0.973 and R² was 0.9934 in the PCA and MAC of other water. In each type of water, there were no significant differences between the PCA and MAC, and the correlation was very high. Thus, it is suggested that the MAC would be available for total aerobic bacteria test for water.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.10
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• pp.2218-2226
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• 2009

TDMA based MAC protocol supporting wireless mesh network has many advantage rather than 802.11 DCF/EDCA protocol based on packet. But TDMA based MAC protocol require new synchronization method because of mobile point oscillator's difference, and distributed environments. This thesis propose synchronization method for TDMA based MAC protocol. It divides MP(Mobile Points) states into 4 types. If MP is in sync mode, it schedules TDMA local start time in time skew interval using beacon. It proposes compensation algorithms to compensate time skew caused by clock drift. This proposal show that general time error and clock drift rate value reduced and get synchronized result.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.141-146
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• 2006

In these days, wireless data services are becoming ubiquitous in our daily life because they offers several fundamental benefits including user mobility, rapid installation, flexibility, and scalability. Moreover, the requests for various multimedia services and the Quality of Service (QoS) support have been one of key issues in wireless data communications. Therefore the research relative to Medium Access Control (MAC) has been progressing rapidly. Especially a number of QoS-aware MAC schemes have been introduced to extend the legacy IEEE 802.11 MAC protocol which has not guaranteed any service differentiation. However, none of those schemes fulfill both QoS features and channel efficiency although these support the service differentiation based on priority. Therefore this paper studies a novel MAC scheme, referred to as Enhanced Distributed Coordination Function with Network Adaptation (EDCF-NA), for enhancements of both QoS and medium efficiency. It uses a smart factor denoted by ACK rate and Network Load Threshold (TH). In this paper, we study how the value of TH has effect on MAC performance and how the use of optimal TH pair improves the overall MAC performance in terms of the QoS, channel utilization, collision rate, and fairness. In addition, we evaluate and compare both the performance of EDCF-NA depending on several pairs of TH and the achievement of various MAC protocols through simulations by using Network Simulator-2 (NS-2).

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.357-360
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• 2000

In this paper, we designed 32-Hit MAC architecture of a RISC Processor for portable terminals such as cellular telephones, personal digital assistants, notebooks, etc. In order to have minimum area with best performance, the MAC performs 32 by 8 multiplication per cycle, with early termination circuit that enables multiply cycles depend on the value of multiplier. It uses the sign bit of a partial product and two extra bits for sign extension, The MAC is modeled and simulated in RTL using VHDL. The MAC is synthesized using IDEC C-631 Cell library based on 0.6$\mu\textrm{m}$ CMOS 1-Poly 3-metal CMOS technology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.3
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• pp.755-761
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• 2013

Medium access control (MAC) protocols for wireless sensor networks make sensor nodes on state for energy-efficiency only when necessary. In this paper we present an energy efficient priority-based MAC protocol for energy-harvesting Wireless Sensor Networks (WSNs). For support priority-based packet transmission the proposed EEPB-MAC protocol uses the modified IEEE 802.15.4 beacon frames including priority bit, sender node address, and NAV value fields. A receiver node periodically wakes up, receives sender beacon frames, selects data sending sender, and broadcasts a beacon frame containing the selected sender's address. A receiver node selects sender node according to sender's data priority. A receiver nodes also adjust wake up period based on their energy states. Hence, the energy consumption of receiver node can be minimized. Through simulations and analytical analysis, we evaluate the performance of our proposed the EEPB-MAC protocol and compare it against the previous MACs. Results have shown that our protocol outperforms other MAC in terms of energy consumption, higher priority packet delivery delay.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3563-3570
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• 2010

MAC protocol has been studied for reducing energy consumption in wireless sensor networks. The overhearing and idle In the existing asynchronous MAC Protocol will occur due to unnecessary energy consumption. In this paper, to solve these problems, the Preamble to change the structure of the destination address, the Preamble of the end times, the data including the length of the Preamble and Data Overhearing reduce the length of the Check Interval Data generated according to the presence of the Dynamic Value dynamically adjustable by changing the DPL (Dynamic Preamble Length)-MAC protocol was proposed. Moreover, the existing asynchronous MAC protocol of wireless sensor networks and DPL-MAC protocol proposed in this paper to simulate the energy consumption and latency were assessed in terms of comparative analysis.

• Journal of Information Processing Systems
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• v.11 no.3
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• pp.465-482
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• 2015

IEEE 802.11p is a standard MAC protocol for wireless access in vehicular environments (WAVEs). If a packet collision happens when a safety message is sent out, IEEE 802.11p chooses a random back-off counter value in a fixed-size contention window. However, depending on the random choice of back-off counter value, it is still possible that less important messages are sent out first while more important messages are delayed longer until sent out. In this paper, we present a new scheme for safety message scheduling, called the enhanced message priority mechanism (EMPM). It consists of the following two components: the benefit-value algorithm, which calculates the priority of the messages depending on the speed, deceleration, and message lifetime; and the back-off counter selection algorithm, which chooses the non-uniform back-off counter value in order to reduce the collision probability and to enhance the throughput of the highly beneficial messages. Numerical results show that the EMPM can significantly improve the throughput and delay of messages with high benefits when compared with existing MAC protocols. Consequently, the EMPM can provide better QoS support for the more important and urgent messages.