• Educational Technology International
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• 제16권2호
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• pp.183-200
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• 2015

This study investigated the effect of learning achievements and cognitive load according to different types of presenting learning materials and epistemological beliefs (EB). Learning achievements in this study were composed by retention and transfer of ill-structured problem. A total of 80 college students participated in the study. Prior to the learning, students were guided to fill out a questionnaire regarding epistemological beliefs and a prior knowledge test. The students of each group studied with a different type of reading material: full text (FT), full text including key questions (KeyFT) and full text including a concept map (CmFT). After a session of study was finished, they were asked to complete the posttest: retention and transfer. The results showed that there was a significant difference in transfer achievements. CmFT outperformed higher scores than the other types. There was no significant difference in retention among the groups. It is strongly believed that the types of presenting learning materials may have affected the understanding of ill-structured problem solving skills. Students with sophisticated EB showed higher achievements on retention and transfer than naive-EB and mixed-EB. Even though the data showed decrease of the cognitive load on the type of materials and EB, there were no significant differences on the cognitive load. We should consider a positive effect of types of presenting learning materials and EB enhancing capabilities of solving ill-structured problems in real life.

• Applied Chemistry for Engineering
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• 제18권2호
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• pp.173-177
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• 2007

EB irradiation method was used to prepare polyvinyl alcohol (PVA) capped silver nanoparticles under various conditions including PVA concentration, $AgNO_3$ concentration, IPA concentration, and EB dosage. The increase in the distribution of particles size was observed with an increase in the concentrations of PVA, $AgNO_3$, IPA, and EB dosage. $AgNO_3$ concentration, IPA concentration, and EB dosage were found to have a great effect on the amount of silver particles formed in PVA matrix by EB irradiation method. These results were confirmed by XRD, UV, and TEM. XRD (X-ray diffraction) technique confirmed the zero valent state of silver. Optical studies were done using UV-visible spectrophotometer to see the variation of silver particles formed in PVA matrix. Transmission Electron Microscopic (TEM) was employed to show the particle size and distribution of silver foamed in PVA matrix.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제49권7호
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• pp.589-592
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• 2021

SOQPSK-TG, which is composed of a precoder and a CPM modulator, adopts a differential precoder method with a differential encoder added to the transmitter as a telemetry standard to simplify the receiver structure. In this paper, we evaluated the effect of the differential encoder on receiver performance at low Eb/No. According to the results of computer simulation, the Eb/No performance in the AWGN channel without the differential encoder is about 2dB better when the BER is 10^-1 and about 1dB when the BER is 10^-2.

• Journal of the Korean Society of Physical Medicine
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• 제5권3호
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• pp.435-443
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• 2010

Purpose : The goal of this study was to identify the effects of treadmill walking training (TW) and ergometer bicycle training (EB) on gait and balance in stroke patients. Methods : The subjects consisted of 42 stroke patients. They were randomly divided to two groups: TW(n=20) and EB(n=22). Each group trained along with the conventional physical therapy, three times a week for six weeks. The ability of gait was assessed by the 10m walk test and Timed Up and Go test(TUG). The ability of balance was assessed by Berg Balance Scale(BBS) and Balance Performance Monitor(BPM). Results : There was no significant difference between the 10m walking test and TUG groups, but there was a statistical difference between before and after the training for all groups. The result of BBS that assessed balance showed a significant reduction between before and after the training for all groups, but there was no difference between the two groups. While the two groups showed no difference in the BPM assessment, only the EB showed a significant improvement of before and after the training in each group. Conclusion : The outcomes suggest that stroke patients can improve their gait and balance performance through the TW and EB trainings. Although dynamic mean balance showed significance from EB, no significant difference was found between two groups. Even though it cannot be determined through this study which training group is more effective among the above mentioned two, it could be suggested that each training is effective to gait ability and the ability of balance of stroke patients.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.739-742
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• 2000

In this paper, we evaluate the throughput and delay performance of a wireless Local Area Network(WLAN) employing the OFDM-based IEEE 802.lla Medium Access Control(MAC) protocol by compute. simulations under wireless indoor. channel. Packet Error Rate(PER) is also investigated for the various Eb/No. It is shown that, with soft-decision Viterbi decoder, throughput and delay performance are close to those of error-free channel at Eb/No above 8dB and PER is about 2${\times}$10$\^$-5/ at Eb/No=10dB.

• Development and Reproduction
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• 제20권4호
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• pp.349-357
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• 2016

The present research was chiefly designed to determine the effect of the treatment of estrogenic agonist, estradiol benzoate (EB), or antiandrogenic compound, flutamide (Flu), at the weaning age on the expression of connexin (Cx) isoforms in the caudal epididymis of adult male rat. Animals were subcutaneously administrated with a single shot of either EB at a low-dose ($0.015{\mu}g$ of EB/kg body weight (BW)) or a high-dose ($1.5{\mu}g$ of EB/kg BW) or Flu at a low-dose ($500{\mu}g$ of EB/kg BW) or a high-dose (5 mg of EB/kg BW). Expressional changes of Cx isoforms in the adult caudal epididymis were examined by quantitative real-time PCR analysis. The treatment of a low-dose EB caused significant increases of Cx30.3, Cx31, Cx32, and Cx43 transcript levels but reduction of Cx31.1, Cx37, and Cx45 expression. Exposure to a high-dose EB resulted in very close responses observed in a low-dose EB treatment, except no significant expressional change of Cx37 and a significant induction of Cx40. Expression of all Cx isoforms, except Cx45, was significantly increased by a low-dose Flu treatment. Expressional increases of all Cx isoforms were detected by a high-dose Flu treatment. The current study demonstrates that a single exposure to estrogenic or antiandrogenic compound during the early postnatal developmental period is sufficient to disrupt normal expression of Cx isoforms in the adult caudal epididymis.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제7권5호
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• pp.893-898
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• 2003

This paper proposes a Truncated Type-II Hybrid ARQ scheme and coding techniques using an adaptive modulation system to achieve high throughput data transmission systems for wireless multimedia communication systems. In this paper, the adaptive modulation system analyzed in Nakagami (m-distribution) fading channel environment. The adaptive modulation system controls the modulation level and symbol rate according to the Nakagami fading parameter(m). When the received Eb/No is high or the Nakagami fading parameter m is high, the propose system selects higher modulation level and higher symbol rate to increase throughput. On the other hand, this system selects lower modulation level and lower symbol rate to prevent throughput performance degradation when the received Eb/No is low. The modulation method have been adopted QPSK(Quadrature Phase Shift Keying), 16QAM(Quadrature Amplitude Modulation), 64QAM, 256QAM. Therefore, adaptive modulation systems with truncated type-II hybrid ARQ scheme is proper for wireless multimedia communication system that require high reliability and delay-limited applications.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.987-1000
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• 2021

The concept of 'Employer branding' (EB) - one effective and sustainable strategy to attract and retain talent - has received a lot of attention from researchers and business managers. This concept becomes more meaningful when the 'war of talent' takes place in an extremely fierce manner in Vietnam as well as around the world. However, this concept is rather new; as a result, many points related to 'EB' scales should be improved, especially in Vietnamese context. Therefore, this study focuses on developing and confirming the EB scale in the context of Vietnam. Based on EB theory, this research applies the mixed research method: qualitative methods (expert interview and group discussion) and quantitative method (questionnaire survey of 937 respondents). EB is demonstrated to be a quadratic concept, consisting of the following 10 dimensions: Corporate social responsibility (CSR), Promotion (PRO), Work-Life Balance Satisfaction (WLSA), Education (EDU), Behavior-based Family interference with work (WLBE), Travel opportunities (TRA), Time-based work interference with family (WLTI), Teamwork (GRO), Supporting (SUP), and Strain-based family interference with work (WLST) with 58 observed variables. Based on the survey towards the employees in enterprises and organizations in Vietnam, the analysis results affirm that this scale ensures efficiency, reliability, unidirectionality and convergent values.

• The Transactions of the Korea Information Processing Society
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• 제7권8S호
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• pp.2679-2687
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• 2000

위성 ATM 망에서 TCP/IP 기반의 응용 서비스를 제공하기 위해서는 위성의 긴 전송지연과 이성 채널의 버스트 오류 특성에 따른 정확한 전송 성능의 영향과 분석이 요구되며, 아울러 성능 목표치가 제시되어야 한다. 본 논문은 2Mbps급 KOREASAT위성을 이용한 위성망과 지상망이 상호 연동된 실제 위성/지상 ATM LANE(LAN Emulation)을 구현하고, 위성 채널의 Eb/No와 TCP 소켓 버퍼 크기, 그리고 전송 메시지 크기를 바꾸어 가면서 그때의 TCP/IP 트래픽과 FTP의 전송성능을 비교 분석하였다. 아울러 IPoA(IP over ATM)기반의 영상회의 서비스에 대한 전송 품질 및 메시지 전달 특성 등을 분석하였다. 연구결과 TCP 소켓 버퍼 크기가 증가할 때 TCP의 전체 성능이 증가함을 알 수 있으나 제한된 최대 윈도우 크기 64kbytes와 위성채널의 오류 특성으로 인해 실제 최대 전송속도는 이론상의 목표치를 달성하지 못함을 보여 주었다. 또한 2Mbps 위성링크에서 Eb/No가 6dB 이하에서는 실제적으로 제공할 수 있는 최대 전송성능의 50%이하로 떨어져 TCP/IP over ATM 서비스가 거의 불가능함을 보여주었다. FTP의 경우, 파일 크기가 작으면 최대 전송속도에 도달하기 전에 파일 전송이 완료되어 대역폭 이용의 효율성 측면에서 TCP/IP의 slow start 메케니즘이 적절하지 않음을 보여주었다. 이울러 IPoA영상회의 서비스에서도 Eb/No가 약 6.5dB 이하에서는 영상이 거의 정지되고, 메시지 전달시간도 ITU에서 권고하는 목표치를 훨씬 상회하여 서비스가 거의 불가능함을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권9호
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• pp.6269-6273
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• 2015

Performance of the Alamouti algorithm based M-ary $2{\times}N$ OSTBC(Orthogonal Space Time Block Coded) MIMO(Multi Input Multi Output) system has been simulated varying two main parameters - the number of constellation(M), and the number of receiving antennas(N). Computer simulation has also been carried out using Matlab software for performance comparison between $2{\times}N$ MIMO and MRC(Maximal Ratio Combining) diversity antenna system to evaluate the degree of enhancement achieved through the use of Alamouti $2{\times}N$ MIMO. Under 10 dB EbNo QPSK scenario, $2{\times}1$ MIMO brought 4.2 dB BER improvement over single antenna system and $2{\times}2$ MIMO resulted in 7.4 dB BER improvement over $1{\times}2$ MRC.