• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1557-1564
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• 2014

In this paper, we propose a signal detection technique based on the parallel orthogonal matching pursuit (POMP) is proposed for generalized shift space keying (GSSK) systems, which is a modified version of the orthogonal matching pursuit (OMP) that is widely used as a greedy algorithm for sparse signal recovery. The signal recovery problem in the GSSK systems is similar to that in the compressed sensing (CS). In the proposed POMP technique, multiple indexes which have the maximum correlation between the received signal and the channel matrix are selected at the first iteration, while a single index is selected in the OMP algorithm. Finally, the index yielding the minimum residual between the received signal and the M recovered signals is selected as an estimate of the original transmitted signal. POMP with Quantization (POMP-Q) is also proposed, which combines the POMP technique with the signal quantization at each iteration. The proposed POMP technique induces the computational complexity M times, compared with the OMP, but the performance of the signal recovery significantly outperform the conventional OMP algorithm.

• Journal of Korea Multimedia Society
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• v.14 no.5
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• pp.669-680
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• 2011

R-trees are widely used in various areas such as geographical information systems, CAD systems and spatial databases in order to efficiently index multi-dimensional data. As data sets used in these areas grow in size and complexity, however, range query operations on R-tree are needed to be further faster to meet the area-specific constraints. To address this problem, there have been various research efforts to develop strategies for acceleration query processing on R-tree by using the buffer mechanism or parallelizing the query processing on R-tree through multiple disks and processors. As a part of the strategies, approaches which parallelize query processing on R-tree through Graphics Processor Units(GPUs) have been explored. The use of GPUs may guarantee improved performances resulting from faster calculations and reduced disk accesses but may cause additional overhead costs caused by high memory access latencies and low data exchange rate between GPUs and the CPU. In this paper, to address the overhead problems and to adapt GPUs efficiently, we propose a novel approach which uses a GPU as a buffer to parallelize query processing on R-tree. The use of buffer algorithm can give improved performance by reducing the number of disk access and maximizing coalesced memory access resulting in minimizing GPU memory access latencies. Through the extensive performance studies, we observed that the proposed approach achieved up to 5 times higher query performance than the original CPU-based R-trees.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.32 no.2
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• pp.68-93
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• 2019

Objective : This study summarized the characteristics of clinical trials for atopic dermatitis medicines approved by the Ministry of Food and Drug Safety(MFDS). This study may be a reference for the design of clinical trials of atopic dermatitis herbal medicine treatment which may be carried out later. Method : The characteristics of the clinical trial were analyzed for clinical trials registered with ClinicalTrials.gov, CRIS, and the Korea Health Industry Development Institute among the clinical trial approval statuses posted on the website of the MFDS. Result : 1. Clinical trial drugs were developed in various formulations such as oral medicines, injections, dermatologic agents, and similar proportions. Relatively little clinical trials were found for herbal medicine. 2. In the control evaluation test, most of the treatments for the control group were performed with placebo using Vehicle. 3. In most clinical trials, one intervention group was in the form of a parallel assignment with only one treatment. 4. The age of the subjects was 11 out of 28 studies including minors, and clinical trials targeting minors were also found to be significant. 5. In the case of atopic dermatitis, the cases of subacute chronic or atopic dermatitis more than 6 months or more than 1 year were often used. 6. Most clinical trials were divided into mild to moderate atopic dermatitis or moderate to severe atopic dermatitis. The SCORAD index, EASI, IGA, BSA, and NRS were used as the evaluation criteria. 7. Regulations for the drugs used prior to the trial period for the treatment of atopic dermatitis vary somewhat from one clinical trial to another. 8. IGA was used most often as a primary efficacy tool, and SCORAD index, EASI, and NRS were also used.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.247-258
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• 2020

In this paper, based on a stochastic parallel gradient descent (SPGD) algorithm we study phase control of a coherent-beam-combining system under turbulent atmospheric conditions. Based on the statistical theory of atmospheric turbulence, we carry out the analysis of the phase and wavefront distortion of a laser beam propagating through a turbulent atmospheric medium. We also conduct numerical simulations of a coherent-beam-combining system with 7- and 19-channel laser beams distorted by atmospheric turbulence. Through numerical simulations, we characterize the phase-control characteristics and efficiency of the coherent-beam-combining system under various degrees of atmospheric turbulence. It is verified that the SPGD algorithm is capable of realizing 7-channel coherent beam combining with a beam-combining efficiency of more than 90%, even under the turbulent atmospheric conditions up to cn2 of 10-13 m-2/3. In the case of 19-channel coherent beam combining, it is shown that the same turbulent atmospheric conditions result in a drastic reduction of the beam-combining efficiency down to 60%, due to the elevated impact of the corresponding refractive-index inhomogeneity. In addition, by putting together the number of iterations of the SPGD algorithm required for phase locking under atmospheric turbulence and the time intervals of atmospheric phenomena, which typically are of the order of ㎲, it is estimated that hundreds of MHz to a few GHz of computing bandwidth of SPGD-based phase control may be required for a coherent-beam-combining system to confront such turbulent atmospheric conditions. We expect the results of this paper to be useful for quantitatively analyzing and predicting the effects of atmospheric turbulence on the SPGD-based phase-control performance of a coherent-beam-combining system.

• Korean Journal of Materials Research
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• v.11 no.12
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• pp.1080-1085
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• 2001

Dielectric properties and leakage current characteristics of 100 nm-thick $Ta_2O_5/Al_2O_3$multilayer thin films, which were fabricated by reactive sputtering of$Al_2O_3$and$Ta_2O_5$ successively on top of each other for total 9 layers, have been investigated with variation of the$Al_2O_3$content$(i.e,\;Ta_2O_5/Al_2O_3 \;thickness\;ratio)$.$Ta_2O_5/Al_2O_3$films were amorphous regardless of the$Al_2O_3$content. With increasing the$Al_2O_3$content from 0% to 100%, refractive index of the $Ta_2O_5/Al_2O_3$films decreased linearly from 2.03 to 1.56 and dielectric constant was lowered from 23.9 to 7.7 Variation of the dielectric constant with the$Al_2O_3$content was in good agreement with the behavior that was obtained by assuming parallel capacitors of$Al_2O_3$and Ta_2O_5$. Leakage current characteristics of $Ta_2O_5/Al_2O_3$ multilayer films were superior to those of $Ta_2O_5$ and$Al_2O_3$films. $Ta_2O_5/Al_2O_3$ films of 5% and 10%$Al_2O_3$content exhibited excellent leakage current densities which were lower than $10^{-7} A/cm^2$ at 1MV/cm.

• Journal of the Korean association of regional geographers
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• v.18 no.1
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• pp.17-26
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• 2012

In Hwangtohyun, meaning 'red soil pass', reddish surface mantles is widespread. Other granitic hills, exceptionally Naju and Youngam area, in Korean peninsula don't commonly have that color. This paper attempts to address this issue by CIA(chemical index of alteration). CIA data and A-CN-K diagram provide crucial insights into the changes in the relative contributions of chemical physical weathering in difference of grus regolith and saprolite. CaO and $Na_2O$ show strong depletion and $K_2O$ is progressive loss. In grus regolith, weathering trends are (sub)parallel to the CN-A join of the A-CN-K diagram, but the sample's composition plot ever closer to the A-K join in saprolite. The difference of weathering trend obtained using CIA data corresponds closely with the visual interpretation of soil color and texture.

• Journal of Acupuncture Research
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• v.33 no.2
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• pp.77-87
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• 2016

Objectives : This is a pilot study for a large randomized controlled trial to investigate the efficacy and safety of a newly developed contrast therapy device-- alternating topical heat and cold -- for patients with chronic low back pain. The main objective of this study is to confirm the feasibility of the study design. Methods : The design was a randomized, 2-arm, parallel-group, single-blind, placebo controlled trial. Patients in each group received real or sham contrast therapy in an acupuncture point 10 times over four weeks. The primary outcome measure was pain intensity on a 100-mm visual analogue scale (VAS). The secondary outcomes were back-related dysfunction based on the Oswestry Disability Index (ODI), the Roland-Morris disability questionnaire (RMDQ), and range of motion of lumbar spine based on the modified Schober test (mSchober test), Finger-to-Floor distance (FTF distance), and Finger-to-Thigh distraction (FTT distraction). Results : A total of 30 subjects with chronic low back pain were randomly assigned to a contrast therapy group (n＝15) or a sham group (n＝15). A repeated-measures analysis of variance showed statistically significant group time interaction for VAS, RMDQ, mSchober test and FTF distance (p<0.05). The treatment group showed significant improvement in pain intensity and functional disability as compared to the sham group. Conclusion : Contrast therapy may be an effective and safe treatment for chronic low back pain.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.207-207
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• 1996

Through molecular cloning, five muscarinic receptors have been identified. The muscarinic receptors can be generally grouped according to their coupling to either stimulation of phospholipase C (m1, m3, and m5) or the inhibition of adenylate cyclase (m2 and m4). Each m1, m3, and m5 receptors has the additional potential to couple to the activation of phospholipase A$_2$, C, and D, tyrosine kinase, and the mobilization of Ca$\^$2+/. However, the differences in coupling efficiencies to different second messenger systems between these receptors have not been studied well. Ectopic expression of each of these receptors in mammalian cells has provided the opportunity to evaluate the signal transduction of each in some detail. In this work we compared the coupling efficiencies of the m1, m3 and m5 muscarinic receptors expressed in chinese hamster ovary (CHO) cells to the Ca$\^$2+/ mobilization and the stimulation of neuronal nitric oxide synthase (nNOS). Because G protein/PLC/PI turnover/[(Ca$\^$2+/])i/NOS pathway was supposed as a main pathway for the production of nitric oxide via muscarinic receptors, we studied on ml, m3 and m5 receptors. Stimulation of guanylate cyclase activity in detector neuroblastoma cells was used as an index of generation nitric oxide (NO) in CHO cells. The agonist carbachol increased the cGMP formation and the intracellular [Ca$\^$2+/] in concentration dependent manner in three types of receptors and the increased cGMP formation was significantly attenuated by scavenger of NO or inhibitor of NOS. m5 receptors was most efficiently coupled to stimulation of nNOS, And, the coupling efficiencies to the stimulation of neuronal nitric oxide synthase in three types of receptors were parallel with them to the Ca$\^$2+/ mobilization.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.726-733
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• 2013

The rotor blade of helicopter is the core component determining helicopter performance and requiring low noise and low vibration because the blade becomes the major source of noise during flight. The performance analysis of candidates rotor blades is very critical because LCH(Light Civil Helicopter) will be developed parallel with LAH(Light Armed Helicopter) as an international upgrade program based on the existing platform of foreign civil helicopter. This research was aimed to recognize the performance of the candidates rotor blades compared with the newly developed foreign rotor blades and to investigate the feasibility about developing korea unique shape rotor blades by analysis the rotor performance and noise. The result of this research can be used for the target performance index during negotiation with foreign helicopter company and developing korea unique shape rotor blades.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.21 no.2
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• pp.111-117
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• 2018

Purpose: The prevalence of obesity has significantly increased among children and adolescents worldwide and is becoming an important health care problem in parallel with the increased prevalence of obesity pediatric non-alcoholic fatty liver disease. Betatrophin is a newly define hormone that is commonly secreted by liver and plays role in glucose tolerance. This study aimed to investigate the relationship between serum betatrophin levels and non-alcoholic fatty liver disease in obese children. Methods: The study included 40 obese children with a body mass index (BMI) above 95th centile, and 35 non-obese subjects with a BMI 3-85th centile, whose age and gender were similar to those of the patient group. For the evaluation of metabolic parameters fasting serum glucose, insulin, alanine aminotransferase, aspartate aminotransferase, lipid profile and serum betatrophin levels were measured. Total cholesterol: high-density lipoprotein cholesterol and low-density lipoprotein cholesterol: high-density lipoprotein cholesterol ratios were calculated as "atherogenic indices." Results: Serum betatrophin levels of the obese subjects were similar to that of non-obese subjects (p=0.90). Betatrophin levels were not correlated with the metabolic parameters. Conclusion: In the present study, levels of betatrophin are not different between obese and insulin resistant children and non-obese subjects, and they are not correlated with atherogenic indices. To elucidate the exact role of betatrophin in obesity, further studies are required to identify the betatrophin receptor and/or other possible cofactors.