• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.11
• /
• pp.2636-2656
• /
• 2013

To improve the cooperative efficiency of node cooperation and multiple access performance for multihop wireless networks, a priority-differentiated cooperative medium access control protocol with contention resolution (CRP-CMAC) is proposed. In the protocol, the helper selection process is divided into the priority differentiation phase and the contention resolution phase for the helpers with the same priority. A higher priority helper can choose an earlier minislot in the priority differentiation phase to send a busy tone. As a result, the protocol promptly selects all the highest priority helpers. The contention resolution phase of the same priority helpers consists of k round contention resolution procedures. The helpers that had sent the first busy tone and are now sending the longest busy tone can continue to the next round, and then the other helpers that sense the busy tone withdraw from the contention. Therefore, it can select the unique best helper from the highest priority helpers with high probability. A packet piggyback mechanism is also adopted to make the high data rate helper with packet to send transmit its data packets to its recipient without reservation. It can significantly decrease the reservation overhead and effectively improve the cooperation efficiency and channel utilization. Simulation results show that the maximum throughput of CRP-CMAC is 74%, 36.1% and 15% higher than those of the 802.11 DCF, CoopMACA and 2rcMAC protocols in a wireless local area network (WLAN) environment, and 82.6%, 37.6% and 46.3% higher in an ad hoc network environment, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.2
• /
• pp.24-35
• /
• 2016

Emergency Vehicle Preemption(EVP) is an operation method which helps to improve response condition of Emergency Vehicle(EV) and it has not yet been introduced in Korea. In order to implement the system, it requires step-by-step plan and selecting a priority area for trial operation. Since a municipal government such as Seoul is too large so it is limited in time and cost to analyze the whole area. Therefore, quantitative and effective selection method for priority area is critical. The aim of this study is to propose a selection method of implementation area for EVP system using the dispatch data analysis. This study also determined the priority area for EVP implementation by analyzing the dispatch data in Seoul and conducted a simulation to evaluate the effects of implementing EVP.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.8 no.3
• /
• pp.53-66
• /
• 2005

The objective of this study is the classification of priority areas for the implementation of green roof by evaluating environmental deterioration in Seoul. Non-permeable pavement, air pollution, habitual floods, energy use, heat island and green space are considered in this assessment indicators. The expert questionnaire survey was conducted in order to determine the most important indicators. These indicators were then, thoroughly evaluated. As a result, high priority areas for the implementation of green roof were deduced in the following order of the districts : Jung, Sungdong, Jungrang, Youngdungpo, Jongro and Kangnam. The highest priority areas were determined to be crowded business-commercial areas. Low priority areas are analyzed in the following order of the districts : Kwanak, Nowon, Seocho and Dobong. The result of this study can be utilized for environmental planning and decision of related policies. Additionally, it can be promoted that awareness of implementing green roof of citizens, policy makers and building owners and effect of green networking between inside and outside Seoul can be increased.

• Journal of the Korea Safety Management & Science
• /
• v.15 no.4
• /
• pp.7-16
• /
• 2013

As workplace incidents has been being declining in Korea, there is criticism of the effectiveness of occupational safety policy implementation. It is unknown that which policy target group needs to be targeted to yield effective injuries prevention. The purpose of this paper is to analyze and reveal the policy intervention group with a high priority in terms of industrial incident prevention and the related investment cost. A Policy Priority Model(PPM) is composed of 6 indicators regarding influences of both the incident reduction and the cost reduction. Z-score analyses are used to confirm the high policy priority area or policy target group. Overall, workplace with worker below 50 persons, construction site with the sales of more than a hundred million won, workplace with relatively small percentage of female employees and relatively higher percentage of older worker should be prioritized to reduce workplace injuries. This paper provides an analytic way that can be used to decide the policy priority workplace in order not only to reduce work-related injuries&illnesses and the related investment cost but to further lessen the related societal costs.

• Environmental Analysis Health and Toxicology
• /
• v.19 no.1
• /
• pp.81-91
• /
• 2004

Although it is suggested that risk -based management plan is needed to manage air pollution effectively, we have no resources enough to evaluate all aspects of substances and set priorities. So we need to develop a logical and easy risk-based priority setting method. However, it if impossible that only one generic system that is consistent with all the use is developed. In this study, we proposed a human health risk based priority-setting method for hazardous air pollutants, and ranked priorities for this method. First of all, after investigating previous chemical ranking and scoring systems, we chose appropriate indicators and logics to goal of this study and made a chemical priority ranking method using these. As results, final scores in priority ranking method were derived for 25 substances, and ethylene oxide, acrylonitrile and vinyl chloride were included in high ranks. In addition, same substances were highly ranked when using default values like when using no default, but the scores of hydrofluoric acid and ryan and compounds were sensitive to default values. This study could be important that priorities were set including toxicity type and quality and local inherent exposure conditions and we can set area-specific management guidelines and survey plans as a screening tool.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.7
• /
• pp.1840-1850
• /
• 1998

In this paper, we propose a priority control algorithm using hop count, called HC-PC(Priority Control Algorithm using Hop-Count) for steaming mode CLS, in wide area ATM networks. In our HC-PC algorithm, hop count of packet is increased by one as traverse CLS hop and is used as loss priority when a CLS buffer is congested. That guards packets with higher priority form congestion. The average packet loss probabilities are evaluated via mathematical analysis for HC-PC algorithm case and no priority control case. The simulationresults indicate that our algorithm may offer better performance in terms of loss fairness for pathe length and yield high utilization of newtork resource.

• Journal of Korea Port Economic Association
• /
• v.27 no.1
• /
• pp.75-94
• /
• 2011

This paper is concerned about applying the AHP(Analytic Hierarchy Process) for a priority analysis of equipment operation plan to improve productivity of the container terminal in Gwangyang port. In this study, main elements of container terminal are assumed as into yard equipment area, transport equipment area, berth equipment area and C/Center area. A questionnaire is used to collect the opinions of equipment operating department and operational planning department. On the whole, the result of the analyses reveals that the most important area is yard equipment area. Examining each department is responses, equipment operating department preferred the C/Center area to other areas, on the other hand, operational planning department preferred yard equipment area. The result of this study suggests some guidelines for deciding priority of operation plan in the container terminal.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.246-248
• /
• 2005

The Controller Area Network (CAN) is being widely used for real-time control application and small-scale distributed computer controller systems. However, CAN may exhibit unfair behavior under heavy traffic conditions. When there are both high and low priority messages ready for transmission, the proposed precedence priority filtering method allows one low priority message to be exchanged between any two adjacent higher priority messages. In this way, the length of each transmission delays is upper bounded. These procedures are implemented as local controllers for the ISHURO (Inha Semyung Humanoid RObot).

• Journal of the Korea Safety Management & Science
• /
• v.13 no.1
• /
• pp.161-166
• /
• 2011

This study proposes a priority model for program directors in charge of Corporate Social Contribution to make the best decision. This empirical analysis aims to discover the most significant area among various programs of Corporate Social Contribution Activities. The Analytical Hierarchy Process (AHP) is used to test the priority model. The study attempts to demonstrate how the model helps providing better decision choices in corporate practices. The priority preference in Corporate Social Contribution Activities programs among corporate social contribution practitioners, PR professors and NGO activists are studied for their priority on corporate social contribution programs, among they valued com mon benefit social activity most important.

• Proceedings of the Safety Management and Science Conference
• /
• 2008.11a
• /
• pp.41-50
• /
• 2008

The study proposes a priority model for program directors in charge of Corporate Social Contribution to make the best decision. This empirical analysis aims to discover the most significant area among various programs of Corporate Social Contribution Activities. The Analytical Hierarchy Process (AHP) is used to test the priority model. The study attempts to demonstrate how the model helps providing better decision choices in corporate practices. The priority preference in Corporate Social Contribution Activities programs among corporate social contribution practitioners, PR professors and NGO activists is examined in order to present preferred programs of corporate social contribution programs, which they value the most as a part of overall social welfare.