• Journal of Communications and Networks
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• v.16 no.2
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• pp.140-145
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• 2014

In this paper, we propose an anti-interference cooperative spectrum sharing strategy for cognitive system, in which a secondary system can operate on the same spectrum of a primary system. Specifically, the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to achieve the target rate. To gain access to the spectrum of the primary system, the secondary system needs to allocate a fraction of bandwidth to help forward the primary signal. As a reward, the secondary system can use the remaining bandwidth to transmit its own signal. The secondary system uses different bandwidth to transmit the primary and its own signal. Thus, there will be no interference felt at primary and secondary systems. We study the joint optimization of time and bandwidth allocation such that the transmission rate of the secondary system is maximized, while guaranteeing the primary system, as a higher priority, to achieve its target transmission rate. Numerical results show that the secondary system can gain significant improvement with the proposed strategy.

• Journal of the Korean earth science society
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• v.38 no.5
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• pp.367-377
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• 2017

The purpose of this research is to investigate characteristics of science content knowledge and pedagogical content knowledge shown in the primary school science classes. Through analysis of classroom teaching, explore the features and differences between primary and secondary school science PCK. Using open-ended interviews with the teachers and group discussions on a regular basis to analyze and compare classes of five primary school teachers, the relationship between CK and PCK. Regardless of the school level the teacher's PCK and professionalism is required with varying focus and emphasis. The features of the primary school teacher's PCK are as follows: Firstly, elementary teach secondary teach content, teachers value pedagogical knowledge (PK) content knowledge (CK). The primary school PCK requires more of understanding of students and teaching methods that to subject areas. PCK be without content knowledge, and the teacher's PCK is subject-specific In addition to the characteristics of PCK in the primary school science teaching, ways to set up professional exchange or collaboration between primary and secondary teachers, and to provide supplementary in-service training focused on content knowledge for primary school teachers.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1549-1558
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• 2011

In this paper, we address the problem of bandwidth sharing among multiple primary users and multiple secondary users in a cognitive radio network. In cognitive radio networks, effective spectrum assignment for primary and secondary users is a challenge due to the available broad range of radio frequency spectrum as well as the requisition of harmonious coexistence of both users. To handle this problem, firstly, Bertrand game model is used to analyze a spectrum pricing in which multiple primary users emulate with each other to acquire maximal profit. After that, we employ Cournot game to model the spectrum sharing of secondary users to obtain optimal profit for each user also. Simulation results show that our scheme obtains optimal solution at Nash equilibrium.

• Journal of Communications and Networks
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• v.11 no.2
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• pp.175-186
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• 2009

A new medium access control (MAC) scheme embedding physical channels into multiband carrier sense multiple access/collision avoidance (CSMA/CA) networks is proposed to provide strict quality of service (QoS) guarantee to high priority users. In the proposed scheme, two priority classes of users, primary and secondary users, are supported. For primary users physical channels are provided to ensure strict QoS, whereas secondary users are provided with best-effort service using CSMA/CA modified for multiband operation. The performance of the proposed MAC scheme is investigated using a new multiband CSMA/CA Markov chain model capturing the primary user activity and the operation of secondary users in multiple bands. The throughput of secondary users is obtained as a function of the primary user activity and other CSMA/CA parameters. It is shown that the new MAC scheme yields larger throughput than the conventional single-band CSMA/CA when both schemes use the same bandwidth.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.12
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• pp.5127-5132
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• 2016

Objective: The aim of this study was to identify associations of internal motivation, perceived health competency, and health literacy with primary and secondary cancer prevention. Methods: A telephone survey was conducted with a sample of 2,700, 30-69 year olds, proportionally extracted from Gangwon Province, South Korea. The dependent variables were actions in primary and secondary prevention and the explanatory variables were 13 questions in three areas: internal motivation (4 items), perceived health competency (4 items), and health literacy (5 items). Result: Multiple linear regression analysis showed that internal motivation, perceived health competency, and health literacy positively impacted primary prevention after controlling for gender and age. As internal motivation, perceived health competency, and perceived literacy increased by 1 point, primary prevention scores increased by 0.11, 0.11, and 0.07 points, respectively. In addition, logistic regression results for secondary prevention showed that health literacy had a positive impact on secondary behavior. As health literacy increased by 1 point, the odds ratio of the practice of secondary prevention was 1.4 times higher. Conclusion: This study suggests that primary and secondary prevention of cancer are significantly related to intrinsic motivation factors, perceived health competency, and actual health literacy. Health literacy concepts that cover the capacity of health management in comprehensive areas need to be applied to education and promotion for improvement of primary and secondary prevention of cancer.

• Journal of the Korean Institute of Educational Facilities
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• v.24 no.2
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• pp.11-18
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• 2017

Most primary and secondary schools in Korea provide school meals to students. After the implementation of the manual in the development of foodservice facilities within schools in the Seoul metropolitan area, this study had been instituted towards the improvement on the design of the school. Through the investigation of the use of school foodservice facilities and the establishment of putting the designer's design to the users into effect, primary and secondary schools have been observed in the study to conclude the following research: Spatial Configuration and Usage Characteristics within Elementary, Middle, and High school.

• Journal of IKEEE
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• v.23 no.2
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• pp.403-406
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• 2019

We propose a low-loss on-chip transformer using an auxiliary primary part (APP) for an output matching network for fully integrated CMOS power amplifiers. The APP is designed using a fifth metal layer while the primary and secondary parts are designed using a sixth metal layer with a width smaller than that of the primary and secondary parts of the transformer to minimize the substrate loss and the parasitic capacitance between the primary and secondary parts. By adapting the APP in the on-chip transformer, we obtain an improved maximum available gain value without the need for any additional chip area. The feasibility of the proposed APP structure is successfully verified.

• Journal of the Korean Institute of Educational Facilities
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• v.1 no.1
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• pp.49-61
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• 1994

This study aims to indicate fundamental problems and also to supply basic data for the reasonable distribution of the educational facilities in an effort to build better educational environments by examining and analyzing their changing process in primary and secondary schools in accordance with the changes in school year system in the period between 1900 to 1993. The following conclusion can be drawn : a. Separation of Middle and high schools due to the change of the school year system in 1951 into 6 - 3 - 3 - 4, has had great influence upon the arrangement of the educational facilities. b. Educational facilities in primary and secondary school are expanding, but they do not meet the criterion on an appropriate scale. Especially educational facilities of high schools need to be extended.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.4
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• pp.179-184
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• 2021

Two types of secondary hardening martensitic steels, 10Co-14Ni and 6Co-5Ni, were produced by vacuum induction melting to investigate the effect of ausforming process on mechanical properties. According to the results of present study, the alloy samples ausformed at low temperature indicated a rather low hardness level in overall aging time despite the refinement of martensite lath width. As the result can closely be related with the presence of primary carbides precipitated within the initial austenite matrix, we confirmed that, in ultrahigh strength secondary hardening martensitic alloy steels, the ausforming process can rather limit the degree of secondary hardening during the subsequent aging treatment.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1621-1628
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• 2016

Experiencing power declines when the secondary coil is at the middle position between two primary coils is a serious problem in segmented on-road charging systems with a single energized segmented primary coil. In this paper, the topological transformation of a primary circuit and a hierarchical compensation capacitor control are proposed. Firstly, the corresponding compensation capacitors and receiving powers of different primary structures are deduced under the condition of a fixed frequency. Then the receiving power characteristics as a function of the position variations in systems with a single energized segmented primary coil and those with double segmented primary coils are analyzed comparatively. A topological transformation of the primary circuit and hierarchical compensation capacitor control are further introduced to solve the foregoing problem. Finally, an experimental prototype with the proposed topological transformation and hierarchical compensation capacitor control is carried out. Measured results show that the receiving power is a lot more stable in the movement of the secondary coil. It is a remarkable fact that the receiving power rises from 10.8W to 19.2W at the middle position between the two primary coils. The experimental are in agreement with the theoretical analysis.