• Environmental and Resource Economics Review
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• v.21 no.2
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• pp.417-439
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• 2012

Recently, the Korean government has announced a stream of countermeasures for stabilizing petroleum product prices. Especially, the Fair Trade Commission proposed a transaction guideline focusing on the petroleum-product blending. The main purpose of this study is to suggest the policy options to induce and promote petroleum-product blending. For this purpose, this paper describes the changes in domestic systems related to petroleum-product blending. In addition, it discusses the major topics for inducing and promoting petroleum-product blending. It would be prerequisites to alleviate or demolish the requirements of separate storage by supplier and exclusive dealing. These options would result in the price decreases at the stages of refinery and gas station. Due to the legal constraint of law revision, it should be also considered to increase more gas stations in wholesale marts and self or franchised independent gas stations.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.11
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• pp.1049-1057
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• 2020

The shift from elite education to mass education in Vietnam has met the demand for education for everybody as well as for quality human resource talent for an emerging nation. Under the resource constraint, understanding the quality dimensions of education and its priority level is important for effective and efficient policies. This study was carried out using both qualitative and quantitative methodologies to develop quality criteria and a ranking model. Two rounds of in-depth interviews were conducted with fifteen experts in the field, who were rectors, employers, and recruitment specialists to develop the quality framework applied in Vietnamese universities under total quality management (TQM), starting from the input of the senior secondary school leavers, through a teaching process to the output. The first round of interviews were unstructured questionnaires designed to explore the main factors in quality assessment model. The second round affirmed the experts' agreement on the assessment model. Then, fuzzy logic was applied to rank eight criteria in the quality assessment model into priority order: cost, teaching and administrative staff, leadership, curriculum, student-related factors, internationalization, admissions, and campus. The results are critical for identifying the necessary actions to enhance the education quality and to further research on the optimal quality model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.603-610
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• 2006

This paper considers the problem of mitigating CCI(Co-channel Interference) in cellular OFDMA downlink systems. The users in the cell-edge area suffer from large CCIs, and their SINR requirements are hard to be maintained. To guarantee their QoS, we propose a new exclusive sub-carrier allocation and power control algorithm. The performance of the proposed two-step algorithm is simulated in SUI-A path-loss model, and it is compared with that of the conventional algorithm. The simulation results show that the data transmission rate in the cell-edge area was increased by 600Kbps within the same power constraint. The results indicate that with proposed algorithm, the data rate stability can be achieved independently of the user location in the cell.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1113-1119
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• 2006

For a multi-user OFDM system in mobile channels which requires low-complexity in adaptive resource allocations, resource allocation algorithm using multi-threshold is proposed. The allocation scheme, which is performed by the multi-threshold values in descending order, considers only subcarriers over each threshold level. Moreover, some subcarriers with the lowest channel gain can be· removed in the present threshold level within the constraint of satisfaction of the required data rate, in order to allocate them to the other users when the allocation process of next threshold is executed. As a result, the proposed bandwidth and subcarrier algorithm has better system performances than the conventional allocation schemes in terms of required power and processing time, which is expected as a technique that improves the spectral efficiency of OFDM systems in a mobile environment.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.4
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• pp.359-371
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• 2001

Project scheduling under resource constraint conditions have contained to many uncertain factors and it is perfonned by human experts. The expert identifies the activities of the project, decides the precedent relationships between these activities, and then construct the schedule using expected activity's duration. At this time, most of the scheduling methods concentrate on one of scheduling factor between activity duration and cost. And the activity duration, which is the most important factor in scheduling, is decided by heuristic of expert. Therefore it may cause uncertainty of activity duration decision and the use of this activity duration may increase the uncertainty of constructed schedule. This paper proposes Fuzzy-MOEH scheduling algorithm, which is the aggregation of the fuzzy number for deciding activity duration and applies the cost function for solving the problems of previous scheduling methods. This paper also analyze the utility and property of Fuzzy-MEOH algorithm through the comparison between Fuzzy-MEOH algorithm and existing MEOH algorithm.

• The Journal of Economics, Marketing and Management
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• v.3 no.3
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• pp.7-23
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• 2015

Women are more disadvantaged than men in many fronts and this confines them to informal sector livelihood activities. Any attempt to improve women's economic status will require information on the organization, cost and returns to investment in the livelihood activities in which they predominate. This is the issue for this study which compared yield performance in artisanal fishing and fresh fish marketing. Primary data collected through multi-stage sampling method were analyzed using inferential statistics, budgeting and regression models. Empirical findings revealed that about 75.0% of fisher folks either had no formal education or acquired only primary school education while 50.0% of marketers had secondary school education. The budgeting model revealed fisher-folks' and marketers' annual net profit to be N2,882,626.00 and N640,227.00, respectively. Profit from fishing was significantly higher than that of fish marketing. At 53.2% for fishing and 40.3% for marketing, returns to investment was better in fishing. Regression model results showed the significant factors influencing returns to each livelihood strategy to include fishing ground, distance covered and years of experience. The major constraint faced by operators of both livelihoods groups was insufficient credit. Despite this, the livelihood strategies were shown to be profitable ventures which contributed to households' consumption expenditure. Organizing women informal sector operators into groups to enhance access to government support and formal credit are recommended for improving livelihood strategy performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5A
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• pp.370-375
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• 2005

While the international standards bodies recommend the dual leaky buckets for the traffic specification for VBR service, video traffic shows burstiness in multiple time-scales. In order to fill this gap between the current standards and real traffic characteristics, we present a standard-compatible traffic parameter selection method based on the notion of a critical time scale (CTS). Since the defined algorithm minimizes the required link capacity under a maximum delay constraint, it could be used as a benchmark even when it can not be implemented easily. Simulation results with compressed video traces demonstrate the efficiency of the defined traffic parameter selection algorithm in resource allocation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.1119-1143
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• 2014

Lightweight trust mechanism with lightweight cryptographic primitives has emerged as an important mechanism in resource constraint wireless sensor based mobile devices. In this work, outlier detection in lightweight Mobile Ad-hoc NETworks (MANETs) is extended to create the space of reliable trust cycle with anomaly detection mechanism and minimum energy losses [1]. Further, system is tested against outliers through detection ratios and anomaly scores before incorporating virtual programmable nodes to increase the efficiency. Security in proposed system is verified through ProVerif automated toolkit and mathematical analysis shows that it is strong against bad mouthing and on-off attacks. Performance of proposed technique is analyzed over different MANET routing protocols with variations in number of nodes and it is observed that system provide good amount of throughput with maximum of 20% increase in delay on increase of maximum of 100 nodes. System is reflecting good amount of scalability, optimization of resources and security. Lightweight modeling and policy analysis with lightweight cryptographic primitives shows that the intruders can be detection in few milliseconds without any conflicts in access rights.

• Journal of Distribution Science
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• v.14 no.2
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• pp.13-22
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• 2016

Purpose - We examine the marginal value of cash in Korean retail firms, largely unexamined in literature. The marginal value of cash plays pivotal role in cash management policy; especially, a significantly low marginal cash value indicates substantial manager-shareholder conflicts. Research design, data, and methodology - We estimate marginal cash values by adopting the approach of Faulkender & Wang (2006). The sample of retail firms traded in Korean Stock Exchange from 1991 to 2013 is analyzed. Results - We estimate the marginal value of cash for the retail firms as 0.75, implying significant manager-shareholder conflicts. We find a lower marginal value of cash for financially constrained retail firms, contradicting existing theories. The marginal value of cash increases substantially after 2000s, suggesting severe agency conflicts in 1990s as a key reason behind our findings. Conclusions - Our findings support the substantial resource diversion problem in Korean firms and the agency theory of cash management policy. Our results argue against the widely accepted view focusing on implications of financial constraints, which highlights a need of new cash management theory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.306-313
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• 2007

In this paper, we efficiently implemented turbo code algorithm in FPGA H/W(hardware) resource. The used turbo code algorithm has the characteristics; the size of constraint is 3, encoder type is 1/3, the size of random interleaver is 2048. The proposed H/W consists of MAP block for calculating alpha and delta using delta value, storing buffer for each value, multiplier for calculating lamda, and lamda buffer. The proposed algorithm and H/W architecture was verified by C++ language and was designed by VHDL. Finally the designed H/W was programmed into FPGA and tested in wireless communication environment for field availability. The target FPGA of the implemented H/W is VERTEX4 XC4VFX12-12-SF363 and it is stably operated in 131.533MHz clock frequency (7.603ns).