• Journal of Communications and Networks
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• v.18 no.3
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• pp.340-350
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• 2016

The performance of large-scale cognitive radio (CR) networks with secondary users sustained by opportunistically harvesting radio-frequency (RF) energy from nearby primary transmissions is investigated. Using an advanced RF energy harvester, a secondary user is assumed to be able to collect ambient primary RF energy as long as it lies inside the harvesting zone of an active primary transmitter (PT). A variable power (VP) transmission mode is proposed, and an energy-based opportunistic spectrum access (OSA) strategy is considered, under which a secondary transmitter (ST) is allowed to transmit only if its harvested energy is larger than a predefined transmission threshold and it is outside the guard zones of all active PTs. The transmission probability of the STs is derived. The outage probabilities and the throughputs of the primary and the secondary networks, respectively, are characterized. Compared with prior work, the throughput can be increased by as much as 29%. The energy-based OSA strategy can be generally applied to a non-CR setup, where distributed power beacons (PBs) are deployed to power coexisting wireless signal transmitters (WSTs) in a wireless powered sensor network.

• Composites Research
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• v.30 no.2
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• pp.138-144
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• 2017

Damage sensing of polymer composite films consisting of poly(dicyclopentadiene) p-DCPD and carbon nanotube (CNT) was studied experimentally. Only up to 1st ring-opening polymerization occurred with the addition of CNT, which made the modified film electrically conductive, while interfering with polymerization. The interfacial adhesion of composite films with varying CNT concentration was evaluated by measuring the wettability using the static contact angle method. 0.5 wt% CNT/p-DCPD was determined to be the optimal condition via electrical dispersion method and tensile test. Dynamic fatigue test was conducted to evaluate the durability of the films by measuring the change in electrical resistance. For the initial three cycles, the change in electrical resistance pattern was similar to the tensile stress-strain curve. The CNT/p-DCPD film was attached to an epoxy matrix to demonstrate its utilization as a sensor for fracture behavior. At the onset of epoxy fracture, electrical resistance showed a drastic increase, which indicated adhesive fracture between sensor and matrix. It leads to prediction of crack and fracture of matrix.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.136-142
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• 2006

Existing buffer management schemes for shared-memory output queueing switches can be classified into two types: In the first type, some constant amount of memory space is guaranteed to each virtual queue using static queue thresholds. The static threshold method (ST) belongs to this type. On the other hand, the second type of approach tries to maximize the buffer utilization in 머 locating buffer memories. The complete sharing (CS) method is classified into this type. In the case of CS, it is very hard to protect regular traffic from mis-behaving traffic flows while in the case of ST the thresholds can not be adjusted according to varying traffic conditions. In this paper, we propose a new buffer management method called weighted dynamic thresholds (WDT) which can process packet flows based on loss priorities for quality-of-service (QoS) functionalities with fairly high memory utilization factors. We verified the performance of the proposed scheme through computer simulations.

• Journal of the Korea Convergence Society
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• v.11 no.2
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• pp.315-321
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• 2020

This research explores the change of smoking cessation motivation, maintenance(6months) from the heavy smokers who have experienced residential treatment. Data was collected by the questionnaires about participates motivation from 1st August 2015 to 31st December 2018. Total participates were 1317 that 1248 males (94.8%) and 69 females (31.3%). The most of participants answered their period of smoking was 31-40years as 31.3% (413p) of total participants. Motivation improved after residential treatment, and the 6-month success group had overall cessation of smoking cessation (F=6.52, p=.011), In the subcategories, pre-contemplation(F=5.12, p=.024), contemplation(F=.90, p= .341), preparation-level1(F=5.79, p=.016) and preparation-level2(F=1.33, p=.249) were statistically significant. Thus, this research investigates that the residential program for smoking cessation actually works to the heavy smokers to increased their motivation and that the 6-month success group had stronger.

• Journal of the Korea Furniture Society
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• v.24 no.3
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• pp.226-238
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• 2013

In the 21st century, boundary between different fields is coming down, convergence and consilience are taking place. It would not be an exaggeration to say key buzzword of the 21st century is 'convergence'. Also in the field of art and design, the border between the two areas is getting more ambiguous. With the reason, both the new awareness and interest on Art Furniture are becoming more heightened. So far as part of the decorative art category Art Furniture was covered. However Art Furniture is now no longer a fixture of that field, but became independent as a new genre of art. As proof of this, at the international representative art fairs including the Design Miami, PAD London, and The Salon of Art and Design which was recently established in New York, etc. Art Furniture is becoming a showcase as the main pieces. Moreover, at the world's major art market Sotheby's, Christie's, and Seoul Auction, Art Furniture's position is more successfully becoming extended. At this point the analysis of the status and the cause on the non-boundary phenomena between art and design is inevitably required to understand the disposition of the public and to develop the domestic furniture industry. Thus, this paper purposes to present the new direction for that the domestic Art Furniture encompasses the two areas with satisfaction to the demands of the public by studying on the non-boundary phenomena between art and design in contemporary Art Furniture.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.322-332
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• 2011

In this paper, we introduce the 1st performance evaluation of VLBI Correlation Subsystem (VCS) main product, which is core system of Korea-Japan Joint VLBI Correlator (KJJVC). The main goal of the 1st performance evaluation of VCS main product is that the perfection of overall system will be enhanced after checking the unsolved part by performing the experiments towards various test items at the manufacturer before installation of field. The functional test was performed by including the overflow problem occurred in the FFT re-quantization module due to the insufficient of effective bit at the VCS trial product in this performance test of VCS main product. Through the performance test for VCS main product in the factory, the problem such as FFT re-quantization discovered at performance test of VCS trial product in 2008 was clearly solved and the important functions such as delay tracking, daly compensation, and frequency bining were added in this VCS main product. We also confirmed that the predicted correlation results (fringe) was obtained in the correlation test by using real astronomical observed data(wideband/narrow band).

• Journal of Convergence for Information Technology
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• v.10 no.2
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• pp.55-62
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• 2020

The purpose of this study is to find out impact of physical health, family strength and psychological well-being on college students in Korea, and to use it as a basic data in developing psycholohgical well-being promotion interventions for college students. The study was composed of 125 students who were studying in 4-year system at colleges. Data were collected from September 1st to October 31st, 2019. Data analysis included an independent t-test, ANOVA, Pearson correlation coefficients and multiple regression using the SPSS 23.0 program. As a result of this study, psychological well-being of those was significantly correlated with physical health and family strenth. In a regression analysis, psychological well-being accounted for 28% of the variance of family strength, physical health and Club activity. The most significant factor affecting the success of psychological well-being was family strength (β=0.34, p<.001). The result of the study indicate the importance of consideration with family strength for psychological well-being of college students.

• The Korean Journal of Food & Health Convergence
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• v.6 no.3
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• pp.23-29
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• 2020

Blood transfusion in the neonatal period remains a therapeutic act, that no one dares to consider it as perfectly innocuous and that it is advisable to make rare, considering its risks as well immunological as infectious. The present work is a retrospective study, conducted in neonatal intensive care unit, in the University Hospital MOHAMED VI, Marrakech, during the period from January 1^st to December 31^st, 2019. All newborns were included in this work, who received one or multiple transfusions of red blood cells (RBC). Our study covered 60 neonates with a total of birth: 794 neonates, with a prevalence of 7.55%, hospitalized for various indications (60% of newborns were at term, 31.7% premature and 8, 33% were post-mature. The majority of transfusion procedures were performed during the first week of life. This is explained by the frequency of haemolytic anemias by fœto-maternal incompatibility. The main indications for transfusion were haemolysis, anemic syndrome and haemorrhagic syndrome. The average number of transfusion episodes was 1.95 +/- 1.47 per patient. Newborns were polytransfused in 18.33% of cases. A single transfusion accident was found in our study. However, we did not observe a correlation between the maternal diseases, the state of the newborn, and the transfusional indication.

• Resources Recycling
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• v.28 no.4
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• pp.37-43
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• 2019

Due to environment problems in end of Life Vehicle in the country, the interest in remanufacturing is heightened than ever. In this study, it is important to quantitatively evaluate the economic effect of the introduction of the automotive remanufacturing business and analyzed cost-benefit for the three species of bumpers, doors, fenders, which is relatively lower remanufactured automotive component. The results showed that cost-beneift of each parts were analyzed 54,000 per one part, and if remanufacturing were 50%, benefits were to occur with a profit of 226,060 won. Thus, remanufacturing of bumpers, doors, fender resulted a significant benefit, and then it is possible that remanufacturing company have enough economic value for remanufacturing.