• 사물인터넷융복합논문지
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• 제8권1호
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• pp.53-58
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• 2022

스무딩은 가변 비트율로 저장된 비디오 데이터를 고정 비트율로 변환하는 전송 계획이다. [6,7]의 연구에서는 전송률 증가가 요구되는 되는 경우에 증가량이 가장 적은 프레임을 새로운 전송률 구간의 시작 프레임으로 설정하고, 전송률 감소가 요구되는 경우에 감소량이 가장 큰 프레임을 새로운 구간의 시작 프레임으로 설정하는 스무딩 알고리즘을 제안하고 네트워크 트래픽이 고려되지 않는 환경에서 성능을 평가하였다. 본 논문에서는 [6,7]의 스무딩 알고리즘을 네트워크 트래픽을 고려한 환경에서 E.T 90 비디오 데이터로 512KB부터 32MB까지 최소 재생률, 평균 재생률, 재생률 변화량으로 적응적인 CBA 알고리즘과 성능을 평가한다. 비교 결과, [6,7]의 스무딩 알고리즘은 최소 재생률 비교에서 우수함을 보였다.

• 대한물리치료과학회지
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• 제15권1호
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• pp.39-45
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• 2008

This study was undertaken to identify the influence which affect on gait speed and energy consumption regarding putting on arm sling during gait of the 40 hemiplegic patients selected from University Hospital and rehabilitation center in seoul during two months. The analysis of data was performed using the paired samples ttest to compare the differences of gait velocity, heart rate, oxygen consumption and oxygen cost in gait of preand post－ arm sling. The results of this study were as follows; 1. When comparing the result before putting on arm sling in the gait of hemiplegic patient, gait velocity after putting on arm sling was statistically significantly increased(p<.05). 2. When comparing the result before putting on arm sling in the gait of hemiplegic patient, heart rate after putting on arm sling was statistically significantly decreased(p<.05). 3. When comparing the result before putting on arm sling in the gait of hemiplegic patient, oxygen consumption per weight after putting on arm sling was statistically significantly decreased(p<.05). 4. When comparing the result before putting on arm sling in the gait of hemiplegic patient, oxygen consumption rate per weight after putting on arm sling was statistically significantly decreased(p<.05). When putting together the above result, the gait with arm sling in comparison with the gait without arm sling was to increase gait velocity, decrease heart rate, decrease oxygen consumption and was finally to decrease energy consumption in the gait of hemiplegic patient.

• 대한기계학회논문집
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• 제11권6호
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• pp.867-876
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• 1987

본 연구에서는 보통강재인 SS 41 강을 열처리하여 얻은 M.E.F.복합조직강의 모상입경변화와 3.5% NaCl수용액의 pH변화 조건하에서 반복굽힘피로실험을 하여 부식 피로파괴에 미치는 영향에 대해 고찰하였다.

• Journal of Computing Science and Engineering
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• 제8권2호
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• pp.107-118
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• 2014

One interesting problem regarding wireless local area network (WLAN) ad-hoc networks is the effective mitigation of hidden nodes. The WLAN standard IEEE 802.11 provides request to send/clear to send (RTS/CTS) as mitigation for the hidden node problem; however, this causes the exposed node problem. The first 802.11 standard provided only two transmission rates, 1 and 2 Mbps, and control frames, such as RTS/CTS assumed to be sent at 1 Mbps. The 802.11 standard has been enhanced several times since then and now it supports multi-rate transmission up to 65 Mbps in the currently popular 802.11n (20 MHz channel, single stream with long guard interval). As a result, the difference in transmission rates and coverages between the data frame and control frame can be very large. However adjusting the RTS/CTS transmission rate to optimize network throughput has not been well investigated. In this paper, we propose a method to decrease the number of exposed nodes by increasing the RTS transmission rate to decrease RTS coverage. Our proposed method, Asymmetric Range by Multi-Rate Control (ARMRC), can decrease or even completely eliminate exposed nodes and improve the entire network throughput. Experimental results by simulation show that the network throughput in the proposed method is higher by 20% to 50% under certain conditions, and the proposed method is found to be effective in equalizing dispersion of throughput among nodes.

• 대한치과교정학회지
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• 제46권3호
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• pp.137-145
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• 2016

Objective: The purpose of this study was to investigate the characteristics of orthodontic patients at Yonsei Dental Hospital from 2008 to 2012. Methods: We evaluated Angle's classification from molar relationships, classification of skeletal malocclusion from the A point-nasion-B point angle, facial asymmetry, and temporomandibular joint disorders (TMDs) from the records of 7,476 patients who received an orthodontic diagnosis. The orthognathic surgery rate, extraction rate, and extraction sites were determined from the records of 4,861 treated patients. Results: The patient number increased until 2010 and gradually decreased thereafter. Most patients were aged 19-39 years, with a gradual increase in patients aged ${\geq}40years$. Angle's Class I, Class II divisions 1 and 2, and Class III malocclusions were observed in 27.7%, 25.6%, 10.6%, and 36.1% patients, respectively, with a gradual decrease in the frequency of Class I malocclusion. The proportion of patients with skeletal Class I, Class II, and Class III malocclusions was 34.3%, 34.3%, and 31.4%, respectively, while the prevalence of facial asymmetry and TMDs was 11.0% and 24.9%, respectively. The orthognathic surgery rate was 18.5%, with 70% surgical patients exhibiting skeletal Class III malocclusion. The overall extraction rate among nonsurgical patients was 35.4%, and the maxillary and mandibular first premolars were the most commonly extracted teeth. Conclusions: The most noticeable changes over time included a decrease in the patient number after 2010, an increase in the average patient age, and a decrease in the frequency of Angle's Class I malocclusion. Our results suggest that periodic characterization is necessary to meet the changing demands of orthodontic patients.

• 대한치과의사협회지
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• 제58권10호
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• pp.627-638
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• 2020

This study was conducted to identify the subjective damage caused by COVID-19 and its related factors. The study subjects were members of the Korean Dental Association (KDA). We investigated the damage to dental clinics and hospitals caused by COVID-19 between January and April 2020. After analyzing the final 3,189 responses, the rate of decrease in patients was the highest at 34.9% in March, and the rate of decrease in income was the highest at 34.0% in April. As a result of the multilevel analysis, the damage caused by COVID-19 was greater in regions with more confirmed patients, more careers, and fewer dental staff. The government should establish a compensation plan for hospitals and clinics to prevent the collapse of the medical system due to the prolonged COVID-19. In addition, support for dentistry should be provided to maintain the oral health care system in the future.

• Ocean and Polar Research
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• 제35권1호
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• pp.51-61
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• 2013

Two surveys were conducted in January 2006 and September 2007 with multibeam echosounder to investigate the dune shape, migration rate, and bedload transport rate using dune-tracking method on an offshore sand ridge at southern Gyeonggi Bay. The migration rates of dunes range from 1.8 $myr^{-1}$) to 56.0 $myr^{-1}$), at the upper northwestern side of sand ridge towards the southwest direction and from the center of the sand ridge towards the northeast direction respectively. Large (i.e. length 10-100 m) dunes show faster migration (0.3-23.4 $myr^{-1}$) ) than very large (i.e. length > 100 m) dunes because larger dunes have required a larger volume of sediments to be displaced. The decreases in dimensions and migration rates of dunes from the center of sand ridge to the lower part of southeastern side on the sand ridge can be ascribed to the decrease of sandy sediments availability, tidal currents with depth, and the coarsening of surface sediments from the crest of the sand ridge to the trough. Bedload transport rates on the basis of migration rates and dune dimensions decrease from 74.5 $m^2yr^{-1}$) at C transect to 35.6 $m^2yr^{-1}$) at R-02 transect.

• Journal of Nutrition and Health
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• 제30권6호
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• pp.658-668
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• 1997

Path of a small hydrophobic molecule through the aqueous cytoplasma is not linear. Partition may favor membrane binding by several orders of magnitude : thus significant membrane association will markedly decrease the cytosolic transport rate. The presence of high concentration of soluble binding proteins for these hydrophobic molecules would compete with membrane association and thereby increase transport rate. For long chain fatty acid molecules, a family of cytosolic binding proteins collectively known as the fatty acid binding proteins(FABP), are thought to act as intracellular transport proteins. This paper examines the mechanism of transfer of fluorescent antyroyloxy-labeled fatty acids(AOFA) from purified FABPs to phosholipid membranes. With the exception of the liver FABP, AOFA is transferred from FABP by collisional interaction of the protein with a acceptor membrane. The rate of transfer increased markedly when membranes contain anionic phospholipids. This suggests that positively charged residues on the surface of the FABP may interact with the membranes. Neutralization of the surface lysine residues of adipocyte FABP decreased fatty acid transfer rate, and transfer was found to proceed via aqueous diffusion rather than collisional interaction. Site specific mutagenesis has further shown that the helix-turn-helix domain of the FABP is critical for interaction with anionic acceptor membranes. Thus cytosolic FABP may function in intracellular transport of fatty acid to decrease their membranes association as well as to target fatty acid to specific subcellular sites of utilization.

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.343-348
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• 2018

Each of the two polycarbonates (PC) of different molecular weights was blended with acrylonitrile-butadiene-styrene (ABS) under high-shear rate processing to afford PC/ABS. Sizes of ABS dispersed phases and mechanical properties of PC/ABS blends were investigated and high-shear rate processing of PC/ABS was carried out by changing screw speed and processing time. Prepared specimens were examined by scanning electron microscope (SEM) to observe morphology changes. Sizes of ABS dispersed phases in PC/ABS blends were observed to decrease gradually as screw speeds increased. Tensile strengths and elongations of specimens were investigated by universal testing method (UTM) to study the influence of molecular weight of PC exerting on PC/ABS blends. As a result, PC1/ABS blends (PC1: higher molecular weight PC) exhibited more strengthened properties than PC2/ABS (PC2: lower molecular weight PC). The tensile strength of PC1/ABS showed an increasing tendency when the screw speed increased, and the elongation did not show a significant decrease, but increased slightly with increasing shear time at a constant screw speed of 1000 rpm.

• International Journal of Fluid Machinery and Systems
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• 제2권3호
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• pp.189-196
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• 2009

The effect of inlet and outlet blade angles on a micro regenerative pump head was examined in experiments. The pump head was little increased by changing the blade angles compared with the original pump with the inlet and outlet blade angles of 0 degree. The effect of the axial clearance between the impeller and the casing on the pump head was also examined. The head was increased largely by decreasing the axial clearance. The computation of the internal flow was performed to clarify the cause of the increase of the pump head due to the decrease of the clearance. The local flow rate in the casing decreased as the leakage flow rate through the axial clearance decreased due to the decrease of the clearance. It was found that the larger head in the smaller clearance was just caused by the smaller local flow rate in the casing. In the case of the smaller clearance, the smaller local flow rate caused the smaller circumferential velocity near the front and rear sides of the impeller. This caused the increase of the angular momentum in the casing and the head.