• KIPS Transactions on Computer and Communication Systems
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• v.2 no.6
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• pp.237-244
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• 2013

We propose Energy-constrained Multiprocessor Real-Time Scheduling algorithms for (m,k)-firm deadline constrained tasks (EMRTS-MK). Rather than simply saving as much energy as possible, we consider energy as hard constraint under which the system remains functional and delivers an acceptable performance at least during the prescribed mission time. We evaluate EMRTS-MKs in several experiments, which quantitatively show that they achieve the scheduling objectives.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1435-1440
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• 2014

Nodes in WSNs must operate under limited energy resource. Controlling access to the channel in WSNs plays a key role in determining channel utilization and energy consumption. This paper introduces a priority-based time slot allocation protocol for hybrid TDMA/CSMA MAC in WSNs. This protocol combines both TDMA and CSMA techniques while introducing prioritization by (m,k)-firm constraint. The performance of this protocol is obtained through simulations for various number of nodes and show significant improvements in delay and packet delivery ratio compared to S-MAC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.356-365
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• 2017

Most studies of the effects of corporate patents on managerial performance conducted to date have been based on internally-generated patents. However, global pharmaceutical and biotechnology companies acquire patents not only from internal research and development (R&D), but also through university-industry collaboration and purchase. Focusing on this issue, our study collected patents from various sources, including internal R&D, purchased patents, and university-industry collaboration, to examine the real effects more accurately. Additionally, our study used a finite time lag model to consider the time lag between patent and corporate performance. The results of the quantitative analysis of the relationship between patents and corporate financial performance revealed that patent quantitative levels had less impact on sales than other types. However, quantitative patents levels appeared to have a significant impact on market value. Moreover, quantitative patent levels appeared to moderate impact on corporate profit. Patents acquired by internal R&D had the greatest impact on market value, while purchased patents had the greatest impact on corporate profit and sales. The purchased patents had a significant effect on financial performance in the pharmaceutical and biotechnology companies because of the long time required and expense associated with R&D. Overall, the results of this study provide the basis for global pharmaceutical and biotechnology companies to configure an optimal patent portfolio.

• The korean journal of orthodontics
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• v.30 no.6 s.83
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• pp.677-685
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• 2000

Anchorage plays an important role in orthodontic treatment. Because of limited anchorage Potential and acceptance problems of intra- or extraoral anchorage aids, endosseous implants have been suggested and used. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period for osseointegration. Titanium miniscrews and microscrews were introduced as orthodontic anchorage due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and their ability to be placed in any area of the alveolar bone. In this study, a skeletal Class II Patient was treated with sliding mechanics using M.I.A.(micro-implant anchorage). The maxillary micro-implants provide anchorage for retraction of the upper anterior teeth. The mandibular micro-implants induced uprighting and intrusion of the lower molars. The upward and forward movement of the chin followed. This resulted in an increase of the SNB angle, and a decrease of the ANB angle. The micro-implants remained firm and stable throughout treatment. This new approach to the treatment of skeletal Class II malocclusion has the following characteristics . Independent of Patient cooperation. . Shorter treatment time due to the simultaneous retraction of the six anterior teeth . Early change of facial Profile motivating greater cooperation from patients These results indicate that the M.I.A. can be used as anchorage for orthodontic treatment. The use of M.I.A. with sliding mechanics in the treatment of skeletal Class II malocclusion increases the treatment simplicity and efficiency.

• Information Systems Review
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• v.17 no.1
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• pp.117-140
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• 2015

Cloud Computing has drawn attention as one of 10 IT strategic technology trends and has various advantages such as cost reduction and enhancing business flexibility. However, corporations hesitate to adopt the service because of unexpected risks. Especially compared to large firm, medium and small ones use public cloud that security risk is high. Meanwhile, real option strategy has drawn attention as the method to hedge uncertainty in IT projects. Therefore, in this study causal relationships among technical, security, relational, and economic risks of cloud service will be investigated. Eventually, this study investigates how those risks influence the intention to choose the real option about the cloud service. For this study, five hypotheses is drawn, and a survey is conducted about the medium and small firms which are currently using cloud service to examine hypotheses. Since the study is at organizational level, 287 questionnaire replies are recalculated to 120 firms. For statistical analysis, Smart PLS and SPSS Statistics18 are used. As a result, technical risk of cloud service has significantly positive influence on security risk. Second, security risk and relational risk of cloud service has significantly positive influence on economic risk. Third, economic risk of cloud service has significantly positive influence on the intention to purchase the delay option or abandon option. Based on this result, this research discussed practical and academic implications and the limitations.

• Journal of Korean Society of Forest Science
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• v.32 no.1
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• pp.29-35
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• 1976

In order to estimate sawmill productivities, rates of technical change and optimum combination of production factors, Cobb-Douglas production functions have been derived using data obtained from 96 sample mills in Busan-Incheon, southwestern and northeastern areas. The results may be summarized as follows: 1. There is a tendency of expanding average sawmill size in the areas. The horse-power holdings per mill have been increased at the rates of 91 percent in Busan-Incheon, 7.7 percent in southwestern and 16.9 percent in northeastern areas. This implies that the mills around log-importing ports have made rapid development, compared with those in forest regions. 2. The regression coefficients (production elasticities) of the functions for the year of 1967 in the above three areas are much similar each other, but significant differencies are found in the production functions of 1975. In other words, sawmill productivity was mainly restricted by capital deficiencies in all areas in 1967, but this situation was succeeded only by N-E area in 1975. The range of sum of regression coefficients is 1.0437-1.4214, this indicates increasing rates of return to scale. 3. The annual rates of technical changes in B-I, S-W and N-E areas for the observed period are 17.6, 7.6 and 2.2 percents respectively. Busan-Incheon is the only area where labor productivity is higher than that of capital. 4. The best combination of production factors for maximizing firm's profit is subject to the changes of input and output prices. With some assumptions of prices and costs, the optimum levels of power and labor input in B-I, S-W and N-E areas are 57:17, 427:94 and 192:27.