• The KIPS Transactions:PartC
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• v.12C no.5 s.101
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• pp.679-686
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• 2005

Because EPON access network shares a medium and aggregates the traffic from EPON subscribers, scheduling media access control on EPON bandwidth allocation is very important. Furthermore DBA mechanism of EPON based on TDMA is out of specification and up to implementation. This paper deals with a DBA method to guarantee the QoS of the delay sensitive traffic on the base of best-effort service and delay priority queue management. The proposed method performs virtual scheduling algorithm for the integrated traffic. It uses the same MAC messages and tries to guarantee the QoS of higher priority traffic first with a simple DBA architecture. We evaluate the algorithm for traffic delay according to polling interval and traffic load of upstream and downstream. The results show that the proposed method can guarantee the QoS of the delay sensitive traffic with priority of the service classes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.425-432
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• 2014

The Enhanced Distributed Channel Access (EDCA) function of IEEE 802.11e standard defines contention window (CW) for different Access Category (AC) limits to support Quality-of-Service (QoS). However, it have been remained the problem that the collision probability of transmission is increasing in congested network. Several different solutions have been proposed but the collision occurs among same priority queue within the same station to compete the channel access. This paper presents an APCA (Advanced Priority Collision Avoidance) algorithm for EDCA that increases the throughput in saturated situation. The proposed algorithm use reserved field's bits of FC(Frame Control) using IEEE 802.11e standard's RTS/CTS (Request to Send / Clear to Send) mechanism to avoid data collision. The simulation results show that the proposed algorithm improves the performance of EDCA in packet loss. Using Jain's fairness index formula, we also prove that the proposed APCA algorithm achieves the better fairness than EDCA method under network congested condition.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.1
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• pp.120-125
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• 2010

The priority job training program is one of key training programs in Korea. This training program has some fundamental problems. The process of selecting the detailed training jobs does not reveal the true training demand of industry sectors. The contracting-out process and control mechanism of the priority job training program show several weaknesses from the points of success conditions of contracting-out public services. In this paper, I proposed development strategies of the priority job training program. The contract period should be longer than one year so that the training institutions may invest for improving quality of training in the longer perspective and reduce transaction costs. The training fee pay mechanism should be more performance-based.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12A
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• pp.1367-1374
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• 2004

Efforts for standardization of medium access control (MAC) protocol in IEEE802.11e have been made to support quality of service (QoS) in IEEE802.11 MAC protocol. Enhanced distributed coordination function (EDCF) of 802.11e MAC protocol is modified to support QoS for packets that have differentiated priority. However, EDCF still has e problem of throughput optimization and priority support. Therefore, we have proposed a scheme called adaptive EDCF for both supporting priority of packets and throughput optimization. We have derived the relation between the number of nodes and contention window size for throughput optimization. Based on the analytic results, we have evaluated the performance of the proposed scheme using OPNET simulations. The simulation results show that using the proposed scheme can Improve the overall throughput regardless of the number of nodes and the decrement of the throughput with increasing the number of nodes can be alleviated. Additionally, we have shown that the adaptive EDCF can support priority of packets more effectively than existing EDCF.

• Journal of Korean Society of Rural Planning
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• v.16 no.4
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• pp.117-129
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• 2010

This study is to make value estimating system to valuate prototype landscape of rural and to derive itemized importance to select priority preservable object The results of the study are summarized as follows, It is examined value estimating standard by analyzing prototype landscape related previous study, law and order. Also, It is derived conclusive prototype landscape value estimating system by doing attribute assessment of preserving objects while surveying the site and interviewing professionals, Value estimating system is classified into five items of physical value which are integration, harmony, diversity, symbolism and aesthetics, The historical-cultural value are divided into four categories which are religious value, originality, historicity and scarcity, The communal values are divided into three categories which are sociality, continuing and regional locality and also divided into three categories which are rarity, primitiveness and diversity as the ecological value, Relative priority of prototype landscape value estimating system result is derived as historical-cultural value as the superior position and physical value, communal value and ecological value as the priority order. In the subordinate, historical categories are derived to be the most valuable and originality, symbolism, integration, regional locality, continuing, harmony, aesthetics, religious value, primitiveness, diversity of physical values and diversity of ecological value in order of the priority assessment The results of the study have the meaning of practical use in prior selection and preservation plan of preserving prototype landscape as practical alternative plan for systematical preservation of damaging prototype landscape.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.175-182
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• 2018

As Internet of things with a large number of nodes emerges, wireless-power communication networks (WPCN) based on a random access protocol needs to be investigated. In the random access-based WPCN, a terminal accessing later in given random access (RA) slots can harvest more energy before transmission and thus can transmit data with higher power and achieve higher throughput if the access is successful. On the basis of this property, the proposed random access control protocol gives the terminals priority and distinguishes the RA slots according to the priority level, so that a near terminal with access point allows to access preferentially other than a remote terminal. This operation decreases the throughput of near terminal and increases the throughput of remote terminal, and then, the doubly near-far problem in WPCN is resolved and the user fairness is improved. Results show that the proposed random access control improves both channel throughput and user fairness according to the priority level.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.804-812
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• 2011

To prevent the overflow of various harmful chemicals, it is necessary to modify the chemical management system with an expansion to institutionally regulated substances. This modification should be preceded by selection of the priority chemicals, with a diverse chemical ranking system (CRS) applied to select the chemicals in developed countries. In Korea, a systematic CRS was used in a project related to soil and groundwater, however, it is inadequate to compare soil and groundwater CRS to that of surfacewater. In this study, a priority chemical ranking system for surfacewater was proposed through the analysis of international and domestic CRS cases. This was then applied to 161 chemicals to derive the priority list of harmful chemicals. As a result, Chemical RAnking of surFacewater polluTants (CRAFT) is presented for the protection of human health and the aquatic ecosystem from surfacewater pollutants. The components of CRAFT are the human health toxicity, aquatic ecosystem toxicity and reliability assessment factors. Three lists were derived from the 161 priority harmful chemicals for the protection of human health, aquatic ecosystem or both. It is expected that this result can be useful to prioritize harmful chemicals for the protection of human health and the aquatic ecosystem from Korean surfacewater.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.11
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• pp.305-314
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• 2017

The purpose of this study is examining the status of Education Welfare Priority Support Project and providing constructive strategies for future direction. In order to collect data, we have used on-line survey, in-depth interview personnels in charge of 17 school districts and open forum with municipal board members of education along with related literature review. As results, since 2003, the effectiveness of the Education Welfare Priority Support Project has been proved and the areas have been expanded. Furthermore, institutional stability has been confirmed along with the supports of enforcement ordinance of the Elementary and Secondary Education Acts and Ministry of Education Ordinances. However, since the management authority of the project has transferred to 17 provincial offices of education, it shows the tendency of that the overall programs were not fully activated and gradually stagnated. According to these issues, we proposed various implemental policy suggestions though the revision of Article 28 of elementary and secondary education-related law.

• Health Policy and Management
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• v.24 no.2
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• pp.181-190
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• 2014

Background: Demands are recently rising for the securement of procedural justification of policy decision-making. This study aims to improve the procedure of making a decision to expand health insurance benefit package from the perspective of building a social consensus. Methods: Major priority principles were firstly derived through literature search. Weights for such principles were calculated through an analytic hierarchy process, based upon the survey conducted for the health policy experts. Priority for 11 non-covered services was assessed by applying the weights as above to the results of the questionnaire survey targeted at people including members of related committees or societies. Results: Weights for priority principles were in the order of 'severity/urgency (0.428)', 'cost-effectiveness (0.318)', 'substitutability (0.164),' and 'accountability (0.090)'. What was obtained by applying these weights to the results of the questionnaire survey was considerably in line with what health experts classified those items into 3 groups depending on their own judgement of service necessity (consistent with 9 services out of 11). Conclusion: Results of the study are suggestive as to how far a brief assessment by experts could be utilized in case there are constraints on time and expenses in implementing all the process to secure procedural justification. Various attempts and endeavors need to be made to secure procedural justification that will not mar efficiency of decision-making in the days to come.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.258-268
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• 2011

Underwater acoustic sensor networks can be used disaster prevention and environmental monitoring systems in underwater environments. Because, the underwater environment is different from the ground, the long propagation delay, low transfer rates and limited bandwidth characteristics should be considered. In this, paper will propose the MAC protocol that allocates time slot into each node according to priority policy through the period of contention-free slot reservation in underwater acoustic sensor networks in order to avoid collision and minimize energy consumption waste. We perform mathematical analysis to evaluate the performance of the proposed protocol with regard to the collision probability, the energy consumption by collision, throughput and channel utilization. We compare the proposed protocol with the conventional protocol, and the performance results show that the proposed protocol outperforms the conventional protocol.