• Title/Summary/Keyword: Flow Prediction

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The Present Situation, its Controversial Points and its counterplans of Korean Students who are Studing Chinese Medicine in China (중국(中國)의 중의약대학(中醫藥大學) 한국유학생(韓國留學生) 현황(現況), 문제점(問題點) 및 대책(對策))

  • Lee, Seon-Dong;Mun, Yong
    • The Journal of Korean Medicine
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    • v.18 no.1
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    • pp.126-142
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    • 1997
  • For last four or five years, the number of Korean students have gone on increasing awfully. After the year 1997 when they will flow in, our field and government will be undergone a big shock and social problems. Therefore, thorough grasping and the method of provision is expeced to need. 1. The situation, According to the data published from the year 1993 to 1997, their results are great different. But recent Korean embassy in China examined the situation of the Korean students, whose result was investigated as follows: about 1500 persons, their average age is 24 to 44, the ratio of male and female students is 3 to 1, that of their academic background which is a graduate of university : that of college : that of highschool is 1.6 : 1 : 4.7, and that of their class attitude which is direct : common : indirect appears the percents 30.4 : 52.8 : 16.8. 2. The controversial points (1) A lowering of standards on Chinese medical treatment is expected by the imprudent studying abroad without qualification. And because of excessive production of herb doctors, the amount of treatment may be above people's demand. Besides owing to the impossibility of prediction on the number the counterplans of our government may fall into utler confusion. (2) The curriculum, the teaching schedule and contents are so different that the graduates seem not to be given real education of chinese medicine from the point of Korean view. (3) In the wrong national examination, the important thought of china, and the system of WTO in Korea, when China will become mighty rival above problems contain the negative sides. 3. The counterplans - what should be performed soon. (1) Illegal contents about studying abroadl in China ought to inform sidely that students might not go on increasing. Before they form nam-power, the government and the field of chinese medicine should cope with such a situation together. (2) The law of regulation about agents should be legislated and they should be surpervised. (3) The exact numbers of students, their situation, and the present condition of each university should be examined. (4) After investigating the problems of the present system of national test, its enforcement and many counterplans is requisite. (5) The cooperating confrontation with the conference of dentistry is in need. (6) Since the problems are possibility to be developed to diplomatic questions, the effort of both nations is needful. - what need middle of long time. (1) The effort that suppress the more establishment of the college of oriental medicine is necessary. (2) After comparing with the system of foreign test, the government should make the system of test in accord with the mutualism and the principle of indiscrimination among nations and cope with such a many issues thoroughly.

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Prediction of Brobchodilator Response by Using $FEF_{25{\sim}75%}$ in Adult Patient with a Normal Spirometry Result (정상 폐활량을 보이는 성인 환자에서 $FEF_{25{\sim}75%}$를 통한 기관지확장제 반응의 예견)

  • Park, Se-Hwan;Lee, Seung-Yup;Kang, Seung-Mo;Seon, Choon-Sik;Kim, Hyun-Kyung;Lee, Byoung-Hoon;Lee, Jae-Hyung;Kim, Sang-Hoon
    • Tuberculosis and Respiratory Diseases
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    • v.71 no.3
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    • pp.188-194
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    • 2011
  • Background: When patients with chronic respiratory symptoms have a normal spirometry result, it is not always easy to consider bronchial asthma as the preferential diagnosis. Forced expiratory flow between 25% and 75% of vital capacity ($FEF_{25{\sim}75%}$) is known as a useful diagnostic value of small airway diseases. However, it is not commonly used, because of its high individual variability. We evaluated the pattern of bronchodilator responsiveness (BDR) and the correlation between $FEF_{25{\sim}75%}$ and BDR in patients with suspicious asthma and normal spirometry. Methods: Among patients with suspicious bronchial asthma, 440 adult patients with a normal spirometry result (forced expiratory volume in one second [$FEV_1$]/forced vital capacity [FVC] ${\geq}70%$ & $FEV_1%$ predicted ${\geq}80%$) were enrolled. We divided this group into a positive BDR group (n=43) and negative BDR group (n=397), based on the result of BDR. A comparison was carried out of spirometric parameters with % change of $FEV_1$ after bronchodilator (${\Delta}FEV_1%$). Results: Among the 440 patients with normal spirometry, $FEF_{25{\sim}75%}%$ predicted were negatively correlated with ${\Delta}FEV_1%$ (r=-0.22, p<0.01), and BDR was positive in 43 patients (9.78%). The means of $FEF_{25{\sim}75%}%$ predicted were $64.0{\pm}14.5%$ in the BDR (+) group and $72.9{\pm}20.8%$ in the BDR (-) group (p<0.01). The negative correlation between $FEF_{25{\sim}75%}%$ predicted and ${\Delta}FEV_1%$ was stronger in the BDR (+) group (r=-0.38, p=0.01) than in the BDR (-) group (r=-0.17, p<0.01). In the ROC curve analysis, $FEF_{25{\sim}75%}$ at 75% of predicted value had 88.3% sensitivity and 40.3% specificity for detecting a positive BDR. Conclusion: BDR (+) was not rare in patients with suspicious asthma and normal spirometry. In these patients, $FEF_{25{\sim}75%}%$ predicted was well correlated with BDR.

Atmospheric Turbulence Simulator for Adaptive Optics Evaluation on an Optical Test Bench

  • Lee, Jun Ho;Shin, Sunmy;Park, Gyu Nam;Rhee, Hyug-Gyo;Yang, Ho-Soon
    • Current Optics and Photonics
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    • v.1 no.2
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    • pp.107-112
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    • 2017
  • An adaptive optics system can be simulated or analyzed to predict its closed-loop performance. However, this type of prediction based on various assumptions can occasionally produce outcomes which are far from actual experience. Thus, every adaptive optics system is desired to be tested in a closed loop on an optical test bench before its application to a telescope. In the close-loop test bench, we need an atmospheric simulator that simulates atmospheric disturbances, mostly in phase, in terms of spatial and temporal behavior. We report the development of an atmospheric turbulence simulator consisting of two point sources, a commercially available deformable mirror with a $12{\times}12$ actuator array, and two random phase plates. The simulator generates an atmospherically distorted single or binary star with varying stellar magnitudes and angular separations. We conduct a simulation of a binary star by optically combining two point sources mounted on independent precision stages. The light intensity of each source (an LED with a pin hole) is adjustable to the corresponding stellar magnitude, while its angular separation is precisely adjusted by moving the corresponding stage. First, the atmospheric phase disturbance at a single instance, i.e., a phase screen, is generated via a computer simulation based on the thin-layer Kolmogorov atmospheric model and its temporal evolution is predicted based on the frozen flow hypothesis. The deformable mirror is then continuously best-fitted to the time-sequenced phase screens based on the least square method. Similarly, we also implement another simulation by rotating two random phase plates which were manufactured to have atmospheric-disturbance-like residual aberrations. This later method is limited in its ability to simulate atmospheric disturbances, but it is easy and inexpensive to implement. With these two methods, individually or in unison, we can simulate typical atmospheric disturbances observed at the Bohyun Observatory in South Korea, which corresponds to an area from 7 to 15 cm with regard to the Fried parameter at a telescope pupil plane of 500 nm.

Parameterization and Application of Regional Hydro-Ecologic Simulation System (RHESSys) for Integrating the Eco-hydrological Processes in the Gwangneung Headwater Catchment (광릉 원두부 유역 생태수문과정의 통합을 위한 지역 생태수문 모사 시스템(RHESSys)의 모수화와 적용)

  • Kim, Eun-Sook;Kang, Sin-Kyu;Lee, Bo-Ra;Kim, Kyong-Ha;Kim, Joon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.9 no.2
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    • pp.121-131
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    • 2007
  • Despite the close linkage in changes between the ecological and hydrological processes in forest ecosystems, an integrative approach has not been incorporated successfully. In this study, based on the vegetation and hydrologic data of the Gwangneung headwater catchment with the Geographic Information System, we attempted such an integrated approach by employing the Regional Hydro-Ecologic Simulation System (RHESSys). To accomplish this, we have (1) constructed the input data for RHESSys, (2) developed an integrated calibration system that enables to consider both ecological and hydrological processes simultaneously, and (3) performed sensitivity analysis to estimate the optimum parameters. Our sensitivity analyses on six soil parameters that affect streamflow patterns and peak flow show that the decay parameter of horizontal saturated hydraulic conductivity $(s_1)$ and porosity decay by depth (PD) had the highest sensitivity. The optimization of these two parameters to estimate the optimum streamflow variation resulted in a prediction accuracy of 0.75 in terms of Nash-Sutcliffe efficiency (NSec). These results provide an important basis for future evaluation and mapping of the watershed-scale soil moisture and evapotranspiration in forest ecosystems of Korea.

A Study on Network Based Traffic Signal Optimization Using Traffic Prediction Data (교통예측자료 기반 Network 차원의 신호제어 최적화 방안)

  • Han, Jeong-hye;Lee, Seon-Ha;Cheon, Choon-Keun;Oh, Tae-ho;Kim, Eun-Ji
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.14 no.6
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    • pp.77-90
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    • 2015
  • An increasing number of vehicles is causing various traffic problems such as chronic congestion of highways and air pollution. Local governments have been managing traffic by constructing systems such as Intelligent Transport Systems (ITS) and Advanced Traffic Management Systems (ATMS) to relieve such problems, but construction of an infrastructure-based traffic system is insufficient in resolving chronic traffic problems. A more sophisticated system with enhanced operational management capabilities added to the existing facilities is necessary at this point. As traffic patterns of the urban traffic flow is time-specific due to the different vehicle populations throughout the time of the day, a local network-wide signal operation plan that can manage such situation-specific traffic patterns is deemed to be necessary. Therefore, this study is conducted for the purpose of establishment of a plan for contextual signal control management through signal optimization at the network level after setting the Frame Signal in accordance to the traffic patterns gathered from the short-term traffic forecast data as a means to mitigate the problems with existing standardized signal operations.

Analysis and Prediction for Spatial Distribution of Functional Feeding Groups of Aquatic Insects in the Geum River (금강 수계 수서곤충 섭식기능군의 공간분포 분석 및 예측)

  • Kim, Ki-Dong;Park, Young-Jun;Nam, Sang-Ho
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.1
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    • pp.99-118
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    • 2012
  • The aim of this study is to define a correlation between spatial distribution characteristics of FFG(Functional Feeding Groups) of aquatic insects and related environmental factors in the Geum River based on the theory of RCC(River Continuum Concept). For that objective we had used SMRA(Stepwise Multiple Regression Analysis) method to analyze close relationship between the distribution of aquatic insects and the physical and chemical factors that may affect their inhabiting environment in the study area. And then, a probabilistic method named Frequency Ratio Model(FRM) and spatial analysis function of GIS were applied to produce a predictive distribution map of biota community considering their distribution characteristics according to the environmental factors as related variables. As a result of SMRA, the values of decision coefficient for factors of elevation, stream width, flow velocity, conductivity, temperature and percentage of sand showed higher than 0.5. Therefore these 6 environmental factors were considered as major factors that might affect the distribution characteristics of aquatic insects. Finally, we had calculated RMSE(Root Mean Square Error) between the predicted distribution map and prior survey database from other researches to verify the result of this study. The values of RMSE were calculated from 0.1892 to 0.4242 according to each FFG so we could find out a high reliability of this study. The results of this study might be used to develop a new estimation method for aquatic ecosystem with macro invertebrate community and also be used as preliminary data for conservation and restoration of stream habitats.

Hexagon-shape Line Search Algorithm for Fast Motion Estimation on Media Processor (미디어프로세서 상의 고속 움직임 탐색을 위한 Hexagon 모양 라인 탐색 알고리즘)

  • Jung Bong-Soo;Jeon Byeung-Woo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.4 s.310
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    • pp.55-65
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    • 2006
  • Most of fast block motion estimation algorithms reported so far in literatures aim to reduce the computation in terms of the number of search points, thus do not fit well with multimedia processors due to their irregular data flow. For multimedia processors, proper reuse of data is more important than reducing number of absolute difference operations because the execution cycle performance strongly depends on the number of off-chip memory access. Therefore, in this paper, we propose a Hexagon-shape line search (HEXSLS) algorithm using line search pattern which can increase data reuse from on-chip local buffer, and check sub-sampling points in line search pattern to reduce unnecessary SAD operation. Our experimental results show that the prediction error (MAE) performance of the proposed HEXSLS is similar to that of the full search block matching algorithm (FSBMA), while compared with the hexagon-based search (HEXBS), the HEXSLS outperforms. Also the proposed HEXSLS requires much lesser off-chip memory access than the conventional fast motion estimation algorithm such as the hexagon-based search (HEXBS) and the predictive line search (PLS). As a result, the proposed HEXSLS algorithm requires smaller number of execution cycles on media processor.

Experiment and Simulation of 2-bed PSA for Hydrogen Separation from H2/CH4 Gas Mixture (수소/메탄 혼합 기체로부터 수소 분리를 위한 두 탑 PSA 실험과 전산 모사)

  • Nam, Gi-Moon;Jeong, Byung-Man;Kang, Seok-Hyun;Lee, Chang-Ha;Lee, Byung-Kwon;Choi, Dae-Ki
    • Korean Chemical Engineering Research
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    • v.43 no.2
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    • pp.249-258
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    • 2005
  • A two-column six-step pressure swing adsorption(PSA) process was to study separation of hydrogen from hydrogen and methane($60_{vol}%/40_{vol}%$) binary system onto activated carbon adsorbent. The effects of the feed gas pressure, the feed flowrate and the P/F(purge to feed) ratio on the process performance were evaluated. The cyclic steady-states of PSA process were reached to after 15 cycles. $H_2$ purity increases according as the P/F ratio and pressure increase and the feed flow rate decreases; however, $H_2$ recovery shows an opposite phenomena to the purity. PSA process simulation studied to find optimum operation condition. In the results, 22 LPM feed flowrate, 11 atm adsorption pressure and 0.10 P/F ratio might be optimal values to obtain more than 75% recovery and 99% purity hydrogen. In this study was non-isothermal and non-adiabatic model considering linear driving force(LDF) model and Langmuir-Freundlich adsorption isotherm considered to compare between prediction and experimental data.

A Study about Internal Control Deficient Company Forecasting and Characteristics - Based on listed and unlisted companies - (내부통제 취약기업 예측과 특성에 관한 연구 - 상장기업군과 비상장기업군 중심으로 -)

  • Yoo, Kil-Hyun;Kim, Dae-Lyong
    • Journal of Digital Convergence
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    • v.15 no.2
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    • pp.121-133
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    • 2017
  • The propose of study is to examine the characteristics of companies with high possibility to form an internal control weakness using forecasting model. This study use the actual listed/unlisted companies' data from K_financial institution. The first conclusion is that discriminant model is more valid than logit model to predict internal control weak companies. A discriminant model for predicting the vulnerability of internal control has high classification accuracy and has low the Type II error that is incorrectly classifying vulnerable companies to normal companies. The second conclusion is that the characteristic of weak internal control companies have a low credit rating, low asset soundness assessment, high delinquency rates, lower operating cash flow, high debt ratios, and minus operating profit to the net sales ratio. As not only a case of listed companies but unlisted companies which did not occur in previous studies are extended in this study, research results including the forecasting model can be used as a predictive tool of financial institutions predicting companies with high potential internal control weakness to prevent asset losses.

Development of Two Dimensional Blade Section with High Efficiency for Marine Propeller (선박 프로펠러용 고효율 2차원 날개단면 개발)

  • Na, Yun-Cheol;Song, In-Haeng;Ahn, Jong-Woo
    • Journal of the Society of Naval Architects of Korea
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    • v.34 no.1
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    • pp.11-23
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    • 1997
  • This paper contains a new approach to blade section design method for marine propellers. The hydrodynamic characteristics of 2-D section are highly influenced by its geometrical parameters i.e., thickness and camber distributions and leading edge radius etc. To consider fully turbulent flow field near 2-D section. the finite volume method with k-${\varepsilon}$ turbulent model which solve Reynolds time averaged Navier-Stokes(RANS) equation is applied. In this study, O-type grid system that can provide many calculation points on blade surface is used. The results were compared with those of the experiment of NACA0012 to confirm the accuracy of the developed codes. The goal of this study is the development of a blade section with high efficiency and low drag. To achieve this, we carried out the tests of lift, drag and cavitation characteristics in cavitation tunnel. The results of experiment were compared with numerical results in order to validate the proposed blades design method. By comparing the numerical results with the experiments, we found that the new blade section, KH28 allows superior performance in efficiency and cavitation avoidance characteristics. We further investigated the blade section design method and an application study of this section, KH28 to apply to the marine propeller. In order to improve the accuracy of numerical results on prediction of lift and drag, we conclude here that the 2-layer boundary model must be used.

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