• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.593-600
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• 2014

OFDMA systems solves frequency selective fading problem and provides improved performance by optimal allocation of subcarriers and transmit power. Two-way relay systems provide improved spectral efficiency compared to that of the conventional half-duplex relay using bidirectional communications. In legacy OFDMA system such as WiBro, two-way DF relay utilization causes pilot re-assignment and impossibility of channel estimation and decoding at relay nodes by self-interference. In this paper, resource allocation schemes for legacy OFDMA systems with two-way DF relay are proposed. The proposed schemes allocate subcarriers considering destinations nodes which are connected to relay nodes as individual nodes which are directly connected to a base station. Subsequently, the proposed schemes compensate bandwidth loss due to orthogonal allocations by overlapped allocating unused subcarriers at other noes. Numerical simulations show that the proposed resource allocation schemes provide improved performance compared with orthogonal allocation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.233-240
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• 2005

In this paper, we have shown the gain recovery time of erbium-doped fiber amplifier(EDFA) in WDM add/drop networks can be reduced to less than $3\mu$sec by employing disturbance observer technique with PID controller which is based on 3-level EBFA model. The $3\mu$sec transient time is the fastest one ever reported and it is about $1\%$ of $250\mu$sec previously obtained from disturbance observer technique with PI controller which was based on 2-level EDFA model and it is also less than $200\mu$sec of commercially available EDFAs for WDM networks. We were able to obtain this result by analyzing various system characteristics as we change the parameters of disturbance observer and PID controller. If this result is applied to a commercial product, the product will do an important role in the future dynamic WDM networks.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.4
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• pp.159-166
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• 2020

The IBC (Intra-Body Communication) benefits from a wireless communication system for exchanging various kinds of digital information through wearable electronic devices and sensors. The IBC using the human body as the transmission channel allows wireless communication without the transmitting radio frequency waves to the air. This paper discusses the results of experiments on electrostatic coupling IBC based on FSK (Frequency Shift Keying) and 1 bit error correction. We implemented FSK communication and 1 bit error correction algorithm using the MCU boards and aluminum tape electrodes. The transmitter modulates digital data using 50% duty square wave as carrier signal and transmits data through human body. The receiver performs ADC (Analog to Digital Conversion) on carrier signal from human body. In order to figure out the frequency of carrier signal from ADC results, we applied zero-crossing algorithm which is used to detect the edge characteristic in computer vision. Experiment results shows that digital data modulated as square wave can be successfully transmitted through human body by applying the proposed architecture of a 1ch GPIO as a transmitter and 1ch ADC for as a receiver. Also, this paper proposes 1 bit error correction technique for reliable IBC. This technique performs error correction by utilizing the feature that carrier signal has 50% duty ratio. When 1 bit error correction technique is applied, the byte error rate at receiver side is improved around 3.5% compared to that not applied.

• Annals of Clinical Neurophysiology
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• v.22 no.2
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• pp.92-103
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• 2020

Background: The purpose of this study was to identify the top-100 cited articles on genetic generalized epilepsy (GGE) published in journals that have made key contributions to the field of epilepsy. Methods: We searched the Web of Science website produced by Clarivate Analytics for articles on GGE, and sorted them according to the number of citations to identify the top-100 cited articles. We then manually reviewed the contents of the top-100 cited articles, which were designated as "citation classics". Results: The top-100 cited articles were published in 27 journals, with the largest proportion appearing in Epilepsia (19 articles). The articles originated from institutions in 17 countries, with 31 articles from the USA. The institution associated with the largest numbers of articles in the field of GGE was the University of Melbourne, Australia (9 articles). Panayiotopoulos C. P. was the first author of three articles, and was listed most frequently in the GGE citation classics. The publication years were concentrated in the 2000s, when 56 articles were published. The most-common study topics were genetics (35 articles) and neuroimaging (17 articles). Conclusions: This study has identified the top-100 cited articles on GGE. These citation classics represent the landmark articles on GGE, and they provide useful insights into international research leaders and the research trends in the field.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.813-820
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• 2013

The purpose of this study was to examine the impact of the reading framework on college students' reflective thinking in argumentation-based general chemistry laboratory. A total of 17 first grade college students taking general chemistry laboratory participated in this study, with 7 in the treatment group and the other 10 in the comparative group. For two semesters, a total of 10 argumentation-based general chemistry laboratory programs were applied. The result was shown that the lessons using the reading framework were effective in enhancing the students' reflective thinking. As the study progressed, the treatment group showed more changes toward the high level of reflective thinking than those of the comparative group.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.4
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• pp.89-102
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• 2015

The purpose of this paper is to attempt to investigate how emotional labor strategies (i.e. surface acting and deep acting) affect job performance and turnover intention thorough emotional exhaustion. Another important objective of this study was to see whether perceived organizational support (POS) moderates the relationship between emotional labor strategies and emotional exhaustion. Structural equation modeling analysis provided support for the hypotheses from a sample of 225 China department store sales employees. The results revealed that surface acting has a positive influence on emotional exhaustion, whereas deep acting has not significant influence on emotional exhaustion. Second, emotional exhaustion has a negative influence on job performance, whereas it has a positive influence on turnover intention. In addition, the relationship between surface acting and job performance/turnover intention was significantly mediated by emotional exhaustion. Furthermore, perceived organizational supporting mitigated the negative relationship between deep acting and emotional exhaustion. The findings of this study contributed to the literature by identifying the relationship between surface and deep acting on employee outcomes (i.e. emotional exhaustion, job performance, turnover intention), especially in China. In addition, this study also confirmed the important buffering role of POS based on the norm of reciprocity between an organization and its members.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.8-8
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• 2019

전 세계적으로 ASR, ASTR과 같은 인공함양에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 수자원을 확보하고 생산수의 수질 개선을 꾀할 수 있는 지하 저수지 기술을 개발하고 낙동강 하구의 염 대수층에 설치한 시험시설에서 검증하였다. 국내외 대 하천의 하구에는 상부에는 점토층이 발달해 있고 하부에는 대수층이 대규모로 발달해 있으나 염 지하수로 포화되어 있는 경우가 많다. 점토층은 오염된 지표수나 지표면에서 발생한 오염사고로부터 하부의 피압 대수층을 분리하는 역할을 할 수 있다. 따라서 피압 대수층은 기존의 지표수 수자원 또는 대체 수자원의 한계를 극복할 수 있는 좋은 수자원 확보 공간이 될 수 있다. 지하 저수지 실증 연구를 위하여 낙동강 하구의 피압 대수층에 주입정, 양수정과 관측정 등을 포함한 시험 시설을 설치하였다. 낙동강에서 취수한 지표수의 부유물을 제거하고 대수층에 주입하여 기존의 염 지하수를 밀어내고 렌즈 형태의 담수체 (지하 저수지)를 조성하였다. 양수정과 관측정을 통하여 조사된 지하 저수지는 원 지하수가 배제되었고, 하천수보다 수질이 개선되었음을 보였다. 본 고에서는 실증 연구에서 도출된 수자원 확보 및 수질 개선 성과를 제시하고자 한다. 지하 저수지는 공사 규모가 작고, 수몰지가 발생하지 않으며, 수요지 인근에 위치해 있어 지역 내 수자원 자급이 가능하고, 토지 이용도 자유롭다. 또한 평상 시에 연중 균일한 양질의 수자원 공급이 가능하고 가뭄, 지표수 오염 등 비상 시에도 장기간 안정적으로 청정 수자원 공급이 가능하다. 지하 저수지는 물 안보도 제고를 위한 취수원 다변화 차원에서 기여할 수 있을 것으로 판단된다.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.41-52
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• 2019

The rapidly changing business environment requires small and medium-sized suppliers to develop creative new products. Therefore, many previous studies have attempted to identify important factors for successful new product development. However, despite the importance of firm learning has generated considerable interest in new product development, the central issue of firm learning remains unanswered. Therefore, this study investigated the effect of adaptive learning of small and medium suppliers on creativity and new product performance in new product development. As a result, it was confirmed that adaptive learning positively affects both novelty creativity and meaningfulness creativity. On the other hand, meaningfulness creativity has a positive effect on new product performance, but novelty creativity has no effect on new product performance.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.5
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• pp.483-490
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• 2019

Due to the high complexity and diversity of the problems of the future society, it is getting harder to solve with the traditional single technology. In recent years, there has been a growing interest in convergence technology, which combines or connects different types of technologies to create new technologies and industries. In this study, we explored the convergence R&D area of ICT technology related to landslide prevention/response. It is true that the world has been exposed to various disasters due to recent climate change. As a result, there is a tendency to use Big Data and ICT for disaster preparedness and recovery. Especially, in the case of landslides, it is a natural disaster that requires research not only to study actual landslides but also to predict potential landslides. Therefore, in this study, we analyzed what kind of convergence R&D is being carried out in the field of ICT for preventing and responding to landslide. Therefore, in this study, Web of Science article data were analyzed by using the scientometric analysis and 51 landslide-related ICT convergence R&D areas were derived.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.1-6
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• 2018

Temperatures of cryogenic nitrogen jet inside an injector and at three different downstream positions (0.9, 10.6, and 28.1d) were measured with thermocouples in sub- and supercritical states. The jet temperature decreased while cooling the supply line and injector. The jet experienced from flash boiling, boiling and then no boiling according to decreasing temperature. As an analogy to flash-boiling at the subcritical state, pseudo-flash boiling has been assumed considering the existence of pseudo-boiling at the supercritical state. By showing an area where the temperature did not increase downstream, the plausibility of pseudo-flash boiling is proposed.