• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.1
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• pp.27-32
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• 2003

Highly reproducible side-wall process for the fabrication of the fine gate length as small as 40nm was developed. This process was utilized to fabricate 40nm InGaAs HEMTs with the 65% strained channel. With the usage of the dual $SiO_2$ and $SiN_x$ dielectric layers and the proper selection of the etching gas, the final gate length (Lg) was insensitive to the process conditions such as the dielectric over-etching time. From the microwave measurement up to 40GHz, extrapolated fT and fmax as high as 371 and 345 GHz were obtained, respectively. We believe that the developed side-wall process would be directly applicable to finer gate fabrication, if the initial line length is lessened below the l00nm range.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.9
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• pp.2154-2172
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• 2013

A centralized cognitive radio (CR) network is proposed and its system capacity is studied. The CR network is designed with power control and multi-user scheduling schemes to support best-effort traffics under peak interference power constraints. We provide an analytical framework to quantify its system capacity, taking into account various key factors such as interference constraints, density of primary users, cell radius, the number of CR users, and propagations effects. Furthermore, closed-form formulas are derived for its capacities when only path loss is considered in the channel model. Semi-analytical expressions for the capacities are also given when more realistic channel models that include path loss, shadowing, and small-scale fading are used. The accuracy of the proposed analytical framework is validated by Monte Carlo simulations. Illustrated with a practical example, the provided analytical framework is shown to be useful for the strategic planning of centralized CR networks.

• Mycobiology
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• v.48 no.6
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• pp.431-442
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• 2020

Penicillium, the most common genus plays an important ecological role in various terrestrial and marine environments. However, only a few species have been reported from rhizosphere soil. As part of a project to excavate Korean indigenous fungi, we investigated rhizosphere soil of six plants in the forest (terrestrial habitat) and sand dunes (coastal habitat) and focused on discovering Penicillium species. A total of 64 strains were isolated and identified as 26 Penicillium species in nine sections based on morphological characteristics and the sequence analysis of β-tubulin and calmodulin. Although this is a small-scale study in a limited rhizosphere soil, eight unrecorded species and four potential new species have been identified. In addition, most Penicillium species from rhizosphere soil were unique to each plant. Penicillium halotolerans, P. scabrosum, P. samsonianum, P. jejuense, and P. janczewskii were commonly isolated from rhizosphere soil. Eight Penicillium species, P. aurantioviolaceum, P. bissettii, P. cairnsense, P. halotolerans, P. kananaskense, P. ortum, P. radiatolobatum, and P. verhagenii were recorded for the first time in Korea. Here, we provide the detailed morphological description of these unrecorded species.

• Current Optics and Photonics
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• v.8 no.5
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• pp.463-471
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• 2024

Multimode fibers (MMFs) possess high information throughput and small core diameter, making them highly promising for applications such as endoscopy and communication. However, modal dispersion hinders the direct use of MMFs for image transmission. By training neural networks on time-series waveforms collected from MMFs it is possible to reconstruct images, transforming blurred speckle patterns into recognizable images. This paper proposes a fully convolutional neural-network model, MSMDFNet, for image restoration in MMFs. The network employs an encoder-decoder architecture, integrating multiscale convolutional modules in the decoding layers to enhance the receptive field for feature extraction. Additionally, attention mechanisms are incorporated from both spatial and channel dimensions, to improve the network's feature-perception capabilities. The algorithm demonstrates excellent performance on MNIST and Fashion-MNIST datasets collected through MMFs, showing significant improvements in various metrics such as SSIM.

• The Korean Journal of Ecology
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• v.27 no.5
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• pp.311-323
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• 2004

To date, restoration ecology has focused on local areas, particularly small-scale ecosystems. As such, restoration ecology has been applied to areas with clear boundaries, such as roads, abandoned mines, wetlands, and forest ecosystems. However, those involved in these restoration efforts, due to their tendency to implement comprehensive plans to change the landscape structure, and their mismanagement of the restoration process, have more often than not wound up weakening the ecological functions of surrounding ecosystems, and in further degrading the ecosystem which they were trying to restore. To resolve these problems and restore a comparatively large-scale region, methods to assess the impact of such restoration efforts on surrounding ecosystems must be developed. These include expanding the scale of restoration efforts; in other words, moving from the local to the landscape scale. As a conclusion, practice of ecological restoration is increasingly moving towards landscape scale in order to deal with these problems.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.52.2-52.2
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• 2013

We explore the relative importance of the role of small-scale environment and large-scale environment in triggering nuclear activity of the local galaxies using a volume-limited sample with $M_r$ < -19.5 and 0.02 < z < 0.0685 selected from the Sloan Digital Sky Survey Data Release 7. The active galactic nuclei (AGN) host sample is composed of Type II AGNs identified with flux ratios of narrow emission lines with S/N > 6 and the central velocity dispersion of the sample galaxies is limited to have a narrow range between 130 < ${\sigma}$ < 200($km\;s^{-1}$), corresponding to 7.4 < $log(M_{BH}/M_{\odot})$ < 8.1 in order to fix the mass of the supermassive black hole at the center of its host galaxy. In this study, we find that the AGN fraction ($f_{AGN}$) of late-type galaxies are larger than of early-type galaxies and that for target galaxy with late-type nearest neighbor, $f_{AGN}$ starts to increase as the target galaxy approaches the virial radius of the nearest neighbor (about a few hundred kpc scale). The latter result may support the idea that the hydrodynamic interaction with the nearest neighbor as well as tidal interaction and merger also plays an important role in triggering the nuclear activity of galaxy. We also find that early-type cluster galaxies show decline of AGN activity compared to ones in lower density regions, whereas the direction of dependence of AGN activity for late-type galaxies is opposite.

• The Journal of Korean Medicine
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• v.40 no.4
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• pp.16-28
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• 2019

Objectives: The purpose of this meta-analysis was to evaluate the effects of Yukgunja-tang(YGJT, Rikkunshito, Liujunzi) on Gastroesophageal Reflux Disease(GERD). Methods: Sixteen electronic databases were used to search for studies published through March 2019, and a randomized controlled study was conducted to study the effects of YGJT or modified YGJT on GERD. Study quality was assessed using the risk bias tool provided by Cochran, and data analysis was performed using Review Manager 5.3.0 software Results: Two-hundred and forty articles were initially searched, and 13 studies that satisfied the study criteria were evaluated qualitatively; 11 of the 13 were included in the meta-analysis. In the two studies, the effects of YGJT and a placebo were compared. Meta-analysis showed that YGJT significantly improved FSSG (Frequency Scale for the Symptoms of GERD) scores, but not GSRS (Gastrointestinal Symptom Rating Scale) scores (FSSG: MD -2.40, 95% CI [-5.31, 0.51], p=0.11, GSRS: MD 0.05, 95% CI [-0.12, 0.22], p=0.55). Meta-analysis of nine studies comparing the efficacies of YGJT and conventional medicine showed that YGJT had a significant clinical effect (OR 5.72; 95% CI [3.41, 9.61]; I2 p<0.00001). Conclusion: This study suggests that YGJT effectively relieves the symptoms of GERD. Unfortunately, owing to the small sample sizes, limitations of several methodological qualities, we believe large-scale clinical studies with less bias will provide evidence of qualitative improvement.

• Korean Journal of Acupuncture
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• v.22 no.4
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• pp.175-185
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• 2005

Objective : The skill of locating acupoints accurately is an essential part of acupuncture treatment. Bone-scale has been used as a basic coordinates to locate acupoints and has been considered as an important factor of locating acupoints. This study was designed to stress the impotance of QieXunMenAn, which means pressing and rubbing softly the surface around the part pointed with proportional method, in locating acupoints. Methods and results : All expressions related with QieXunMenAn, among the descriptions of acupoint locations in ${\ulcorner}Zhenjiudacheng{\lrcorner}$, were investigated. The activity of QieXunMenAn has been regarded as an important method of locating acupoints since Neijing. QieXunMenAn means pressing and rubbing softly the surface around the part pointed with proportional method. It is a process of locating acupoint in detail by finger-sensation after locating the point with proportional method. Xianzhang, Dongmaiyingshou, and Wanwanzhong have been used to describe how to locate acupuncture-point through QieXunMenAn procedure. Xianzhong means a small depression or a pit on the surface of the body. Wanwanzhong describes that it feels very soft and tender. Descriptions related with QieXunMenAn procedures were found in around 87% of acupoint locations, thus stressing out its procedure. Conclusions : Bone-scale and QieXunMenAn do not mean different methods but the procedures that should be both performed every time when we locate most of the acupoints. Until recently, QieXunMenAn has been paid less attention that it should be. OieXunMenAn as well as bone-scale may be necessary to help locate acupoints accurately.

• The Korean Journal of Elementary Counseling
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• v.5 no.1
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• pp.227-253
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• 2006

It seems common for students living at a small county and islands to experience psychological conflicts and be unaccustomed in the peer society because they are not familiar with peer interaction and social skills. This is a case study of L (hereinafter called L) who was grown up in the sheltered school at a small county. L was psychologically disturbed because he couldn't get along well in the transferred school. It is the reason why he had lived in the sheltered school at a small county, so he had not enough exposure to interact with peer and social skills. Sometimes he was obstinate irrationally and when he had trouble with friends, he threw something out or went out of school and tricked juniors dangerously. The fact of disperse with families, parent's indifference, and hate of older brother made L to have ill feeling against family. He had low motivation and low self confident in learning because of short attention time and accumulated poor learning progress. In this study, he was evaluated at various area, such as, intelligent, affective, personal and inter-personal, before counselling. To evaluated the effect of the counselling, K-WISC-III, KPRC, sentence filling test, social adaptation ability test, etc, were administered right after the counselling was over and 8 weeks later. For specific information gathering and analysing, observation diary and deepen counselling were accomplished by homeroom teacher, his mother, and his peers. To correct his problematic behaviors, 13 counseling sessions were accomplished for 6 months and those counselling sessions were recorded and analysed definitely. Followings are the result of this case study. First, he was recovered from the anxiety of inter-personal interaction and he started to interact with peers. The result of sac scale score of KPRC profile was lower than before as much as average student after counseling and 8 weeks later. This reveals that the distress against interpersonal relation have settled. Especially, through the result of sentence filing test, he seemed to feel attachment to peers and be positive, active in the relation of peer. For instance, he was active in the open class lesson and interacted well with peers. It could be said that he overcame the psychological distress comparing with previous time. Second, he could apologize to his peer and juniors for his fault. His attitude were well shown in the letter from an old friend at the sheltered school, average KPRC profiling score comparing with previous counseling time, and remarkable decrease of attack scale score of teacher and peer. Third, his view toward family turn out positive. He recognized his situation that he lived apart from family and even worried about his parent's financial difficulty. Through solving the confliction with his older brother, he could acquire the feeling of family reunion. Fourth, his learning motivation and self-confidence were increased. He confirmed his future positively and he might be judged more attentive because his intelligence index was higher than before as much as average student. With the main goal of this study, verification for effectiveness of counseling. understanding and helping problematic students such as L who lives at a small county and island through investigation of their real situation and problems with the method of counseling and socio-cultural analysis is worthwhile. Identification of ideal relationship with peer is related with positive self-conception, harmonic social adaptation and development of child. It is time to investigate easy adaptive in classroom and well-organised program to acquire general social skills for sheltered school students at a small county and islands.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.911-918
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• 2016

A conical roll-shaping process was proposed for fabrication of a metallic spiral blade applied to a small-scale wind turbine system. A spiral blade has continuously different curvatures, with a range of 100 to 350 mm radius. To fabricate this complex shape, we developed a conical roll-shaping process having two main conical rollers for feeding a blank sheet, and two cylindrical side rollers for control of local bending. For clear understanding of the process parameters, numerical analyses were conducted using a commercial code, Pam-Stamp. This study optimized the effects of process parameters, such as gap and angle between the main rollers and side rollers, and also the movement of side rollers. In order to increase the forming efficiency, a central rotation point was also calculated by the analytical approach. This developed rolling process can thus be utilized in a sheet metal forming process for obtaining spirally curved sheet metal shapes.