• Journal of Satellite, Information and Communications
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• v.9 no.3
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• pp.91-97
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• 2014

In this paper, we propose weighted detection probability with distance between primary user and secondary users by using cooperative spectrum sensing based on energy detection. And we analysis and simulate the result. We suggest different distance between primary user and secondary users and the wireless channel between primary user and secondary users is modeled as Gaussian channel. From the simulation results of the cooperative spectrum sensing with weighted method make coverage bigger compared with non-weight, and We show higher sensing efficiency when we put weight detection probability than before method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1111-1130
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• 2016

Cooperative communications can significantly improve the wireless transmission performance with the help of relay nodes. In cooperative communication networks, relay selection and power allocation are two key issues. In this paper, we propose a relay selection and power allocation scheme RS-PA-PSACO (Relay Selection-Power Allocation-Particle Swarm Ant Colony Optimization) based on PSACO (Particle Swarm Ant Colony Optimization) algorithm. This scheme can effectively reduce the computational complexity and select the optimal relay nodes. As one of the swarm intelligence algorithms, PSACO which combined both PSO (Particle Swarm Optimization) and ACO (Ant Colony Optimization) algorithms is effective to solve non-linear optimization problems through a fast global search at a low cost. The proposed RS-PA-PSACO algorithm can simultaneously obtain the optimal solutions of relay selection and power allocation to minimize the SER (Symbol Error Rate) with a fixed total power constraint both in AF (Amplify and Forward) and DF (Decode and Forward) modes. Simulation results show that the proposed scheme improves the system performance significantly both in reliability and power efficiency at a low complexity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1590-1610
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• 2016

The challenge of penetrating obstacles along with impact from weak multipath effects makes 60GHz signal very difficult to be transmitted in non-line of sight (NLOS) channel. So 60GHz system is vulnerable to obstructions and thus likely results in link interruption. While the application of cooperative technology to solve link blockage problemin 60GHz system should consider the characteristic of directional transmission for 60GHz signal. Therefore in this paper a system is proposed to solve the link blockage problem in 60GHz NLOS communication environment based on the concept of cooperation and also the beamforming technology, which is the basis of directional transmission for 60GHz communication system. The process of anti-blockage solution with cooperative communication is presented in detail, and the fast switching and recovery schemes are well designed. The theoretical values of symbol error rate (SER) using decode and forward (DF) cooperation and amplify and forward (AF) cooperation are presented respectively when the common channel interference exists. Simulation results demonstrate that the performance based on DF cooperation is better than the performance based on AF cooperation when directional transmission is used.

• Research in Community and Public Health Nursing
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• v.30 no.1
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• pp.57-68
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• 2019

Purpose: This study was performed to determine effects of a structure-centered cooperative learning safety education program based on blended learning for elementary school students. Methods: The study is developed in nonequivalent control group non-synchronized design. The subjects included 24 sixth grade students in the experimental group and 23 sixth grade students in the control group, respectively. To prevent diffusion of the experiment, it was carried out from May 20th to June 24th in 2015 with the control group and the other from August 26th to September 30th in 2015 with the experimental group. It was performed on experimental group after the structure-centered cooperative learning safety education program based on blended learning once a week for 6weeks. Data were analyzed by using descriptive statistics, paired t-test and independent t-test. Results: After the intervention, the experimental group showed significant increases in the self-directed learning attitudes and safety behavior compared to the control group except for the academic self-efficacy. Conclusion: The results indicate that the structure-centered cooperative learning safety education program based on blended learning program is effective in safety education for 6th graders.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.351-357
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• 2007

In this paper, we propose a new cooperative signaling structure based on CDMA to overcome both 2/3 spectrum efficiency and low diversity gain of conventional cooperative signaling through continuous overlapping of signal that each user wants to transmit. Proposed signal structure can achieve the spectrum efficiency nearly "1" by receiving additional data for next time as well as maximum diversity gain to detect data continuously at both base station and each user. The orthogonality of CDMA's spreading codes can improve performance of optimal detector by reducing inter-user channel environment and distinguishing each user. We perform the computer simulation to verify the proposed system through comparing cooperative mode and non-cooperative mode under Rayleigh fading channel plus AWGN (Additive White Gaussian Noise).

• Korean Journal of Organic Agriculture
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• v.28 no.3
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• pp.367-386
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• 2020

The significance of this study was to analyze the quality value of organic livestock pork for the first time based on the results of managing and testing the cycling organic farming of black pork and vegetables within farm for two years. The results of analysis could be summarized as follows. First, the pork of experimental group with crop-livestock cycling farming showed the excellent quality and high consumer preference compared to the control group of general pork or pork from non-crop-livestock cycling organic farming. In the content ratio of Omega-3 as a representative essential fatty acid, it was 1.46 that was about 2.8 times more than general pork (0.52). In case of Omega-6, it had about 2.5 times more than general pork. Especially, the U/S ratio value which was the content ratio of Unsaturated Fatty Acid (UFA, U) of Saturated Fatty Acid (SFA, S), was largely shown in pork (2.93) from cycling organic farming. Second, it would be necessary to maintain the economies of scope shown in crop-livestock cycling organic farming, and the high quality value of livestock products. For this, there should be a value chain model that could realize the economies of scope and economies of scale at the same time based on scaling and diversification through cooperative organization between farmers. Through this, it would be possible to establish a cycling model called 'community cooperative agriculture' by forming local internal markets through cooperation of production-processing and integration of distribution-sale-consumption. For the managerial activation of this cooperative organization, the government should promote/support the small crop-livestock cycling organic farming cooperative organization in local unit. For securing the reliability of crop-livestock cycling organic agricultural products and crop-livestock cycling organic livestock products, it would be necessary to review the introduction of Participatory Guarantee System (PGS).

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.2
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• pp.158-165
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• 2018

Recently there is a great interest in the bi-static sonar. However, since the transmitter and the receiver operate on different platforms, it may be necessary to operate the system in a non-cooperative mode. In this situation, the detection and localization performance are limited. Therefore, it is necessary to classify the received pulse from the transmitter to overcome the performance limitation. In this paper, we proposed a robust automatic pulse classification method that can be applied to real systems. The proposed method eliminates the effects of noise and multipath propagation through post-processing and improves the pulse classification performance. We also verified the proposed method through the sea experimental data.

• Journal of Agricultural Extension & Community Development
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• v.9 no.2
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• pp.263-277
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• 2002

The objective of this study was to compare the farm efficiency of members of cooperative firms with that of non-members in Korea. Data were collected from 27 farms members of three cooperatives and 13 non-member farms, based on the managerial achievements of 1999. For the analysis, the data were divided into three different farming types: type I and II of member farms and non-member farms. Economic analysis were implemented using DEA(Data Envelopment Analysis). Major findings was as follows. Total average technology efficiency was 0.782, which implies that there still remains 21.8% of improvement possibility. Among the three types, type I showed the highest technology efficiency of 0.9055, while type II and non-member farms showed 0.7670 and 0.7171, respectively. This means that these farms have relatively high potential improved. Also, comparing technology efficiency by dividing into pure technology and scale efficiency, all type of the farms exhibit a higher pure technology efficiency compared to scale efficiency. Therefore, to improve current technology efficiency, farms need to focus more on pure technology efficiency improvement. Meanwhile, profit analysis based on farm size indicate that most of the farms demonstrated the increasing-return-to-scale, which means it is necessary to extend the farm size to improve technical efficiency. Type I member farms achieve higher profit and efficiency than other two types and relatively higher producer prices through introducing cooperative sorting, grading and packing. Also, these labor saving technologies increased farm size.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5945-5950
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• 2014

Objectives: To retrospectively review the safety and clinical efficacy of bevacizumab concomitant with chemotherapy in Chinese patients with advanced non-squamous non-small cell lung cancer (NSNSCLC). Methods: Clinical data for 79 patients with NSNSCLC who received bevacizumab concomitant with chemotherapy in Chinese PLA General Hospital from April 28th 2009 to May 5th 2013 were retrospectively reviewed to analyze the clinical efficacy including disease control rate (DCR), overall response rate (ORR), progression-free survival (PFS), overall survival (OS), the Eastern Cooperative Oncology Group (ECOG) score and the safety. Results: The Eastern Cooperative Oncology Group (ECOG) score was 0-2. By the final cutoff date (June 9, 2013), 54 (68.4%) patients had disease progression and 37 (46.8%) died. The ORR was 32.9% and the DCR was 83.5%. The ORR of the first-, second-, and third- or later-line treatments were 51.4%, 25.0% and 12.5%, while the DCR were 94.3%, 80.0% and 70.8%, respectively. The median OS (mOS) and PFS (mPFS) were 13.5 and 5.83 months, respectively. The mOS of patients with the first-, second-, and third- or later- line treatments were 16.2, 10.9 and 8.30 months, while the mPFS were 7.27, 5.90 and 5.17 months, respectively. Chemotherapy-related adverse events included myelosuppression, vomiting, hepatic dysfunction and renal dysfunction, while the common serious bevacizumab-related adverse events were thromboembolic problems, gastrointestinal perforation and reversible posterior leukoencephalopathy syndrome, which could be well managed. Conclusions: Bevacizumab concomitant with chemotherapy is effective and the related toxicity can be well tolerated in Chinese patients with NSNSCLC.

• Journal of Engineering Education Research
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• v.25 no.2
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• pp.22-31
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• 2022

This study was conducted to investigate the effect of learning style and lecture attitude on academic achievement in non-face-to-face lectures. Among students attending H University in the first semester of 2020. 1,880 students voluntarily participated in the survey. The questionnaire consists of 33 questions, and actual GPA was used to determine academic achievement. In this study, ANOVA and regression were utilized to find out the factors affecting academic achievement. The results are as follows. First, in the correlation between learning style types, the higher the avoidant learning style, the lower the independent, cooperative, and competitive types. Second, the higher the independent learning type, the higher the positive lecture attitude and GPA, and the higher the type of cooperative learning, the higher the negative lecture attitude. Third, the positive attitudes of 4th graders were higher than that of 1st graders. Fourth, there was no difference in learning style between colleges. Fifth, independent/competitive learning styles and non-face-to-face lecture attitudes had a significant effect on academic achievement in non-face-to-face lectures. In conclusion, in order to narrow the academic gap, instructors must identify the type of learning style. And it is necessary to consider students' preferences for non-face-to-face lectures.