• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.122-128
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• 2000

Aerodynamic optimization of an automotive air-conditioning blower is a hard task because of the highly complex flow phenomena related to three-dimensional flow separations and the unsteady nature caused by the interaction between primary and secondary air flows throughout the fan. In this paper, an aerodynamic study on a forward-curved centrifugal fan has been carried out Firstly we obtained the fan performance curves versus flow rates showing its unstable nature in the surging operation range. Secondly aerodynamic characterizations were carried out by investigating the velocity and pressure fields in the casing flow passage using a 5-hole pilot probe, at different operating conditions. Surface flow pattern near the cut-off area exhibits similar flow behavior above the best efficiency operating point, although the pressure level increases substantially with the Increase of flow rate. Vorticity in the casing passage flow occurs in all (low rates, downstream from the r-Z plane $\theta$=120 deg., where the position of its core changes with the circumferential location. Although complex, the general flow behavior were common, giving insight in its main aerodynamic features.

• Lingua Humanitatis
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• v.6
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• pp.295-320
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• 2004

$\ulcorner$Xixiangji[West chamber]$\lrcorner$ is one of the most popular Chinese dramas which was first translated into Korean by Chung-hee Kim in 1811. $\ulcorner$Dongsanggi[East chamber]$\lrcorner$is a Korean drama which was written in Chinese by Ok Lee in 1791. It adopted the form of Chinese traditional drama, $\ulcorner$xixianji$\lrcorner$. 1 think theses are very interesting examples which show how we accepted Chinese dramas through translation or modification and created our own dramas in the past. 1 quoted their names in the title because it is thought that they can represent the direction of the stream of cultural exchange between two countries in the past. The direction has recently changed. Han stream[Korean cultural effect] has become very powerful in whole Asia in last 10 years. Cultural exchange between Korea and China has been very steady and popular over 2000 years before the 20th century We used to have cultural identity by using Chinese character and accept many of the cultural aspects from China. Now, we are trying to reestablish the relationship which has been cut off for about 50years. In this paper I tried to retrospect the results of cultural exchange in the past and argue about the problems we are now facing by examining interchange or acceptance of the Chinese drama including translations and theatrical performances. 1 also tried to suggest the diverse ways of mutual exchange to uplift the cultural level of two countries.

• Wind and Structures
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• v.24 no.4
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• pp.351-365
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• 2017

The minimization method is widely used to predict the dynamic characteristics of a system. Generally, data recorded by experiment (for example displacement) tends to contain noise, and the error in the properties of the system is proportional to the noise level (NL). In addition, the accuracy of the results depends on various factors such as the signal character, filtering method or cut off frequency. In particular, coupled terms in multimode systems show larger differences compared to the true value when measured in an environment with a high NL. The iterative least square (ILS) method was proposed to reduce these errors that occur under a high NL, and has been verified in previous research. However, the ILS method might be sensitive to the signal processing, including the determination of cutoff frequency. This paper focused on improving the accuracy of the ILS method, and proposed the modified ILS (MILS) method, which differs from the ILS method by the addition of a new calculation process based on correlation coefficients for each degree of freedom. Comparing the results of these systems with those of a numerical simulation revealed that both ILS and the proposed MILS method provided good prediction of the dynamic properties of the system under investigation (in this case, the damping ratio and damped frequency). Moreover, the proposed MILS method provided even better prediction results for the coupling terms of stiffness and damping coefficient matrix.

• KSBB Journal
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• v.23 no.2
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• pp.169-176
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• 2008

The concentration of fresh gel from Aloe vera L. by using ulfrafiltration (UF) process was investigated and analyzed. The two membranes (organic and ceramic) with different molecular weight cut-off (MWCO) and modules (flat sheet and tubular) was used. Under optimum operation conditions, ceramic (zirconium dioxide) tubular membrane with MWCO of 50 kDa resulted in higher flux, less fouling, more turbid, higher total solid, higher polysaccharide and less aloin content. Optimum operation conditions were transmembrane pressure of 1.0 bar, feed velocity of 240 L/hr and temperature of $23^{\circ}C$. Volume concentration factor of aloe gel was 3.13 at permeate flux of $51.1\;L/m^2{\cdot}hr$ after processing time of 1.66 hr. Aloin in fresh aloe gel by UF process was effectively removed as permeate and bioactive polysaccharide content was 2.1 times higher than that of fresh aloe gel. These results allowed a very good level of concentration degree and polysaccharide content. Thus, ultrafiltration process of this study was suitable for the concentration of fresh aloe gel though the aloe concentrate showed both the viscosity decrease and partially separation of liquid layer during storage at $4^{\circ}C$.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.172-185
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• 2009

This paper presents case histories and research projects related to geotechnical challenges at waste landfill sites in Japan. Due to the limitation of inland space available to waste disposal, coastal landfills and the associated containment systems are important considerations, particularly for metropolitan areas. Experimental works on heavy metals mobility using a large column to simulate the redox potential at the coastal landfill sites are introduced. After the closure of landfill sites, they are expected to be utilized as new land space, since new space is difficult to find in urban area. In the redevelopment of such closed landfill sites, there are possibilities of environmental risks, such as generation of toxic gas and leachate, differential settlement of the waste layer, damage to the lining system. Whether the pile installation through the clay layer acting as a landfill bottom barrier is environmentally acceptable or not has been a great concern in the redevelopment of closed waste landfill sites in particular coastal landfill sites. An analytical study to evaluate the cost-effective remedial option for a dumped waste site located along a landslide area, where cut-off wall keyed into the aquitard might elevate groundwater level and thus may not be employed, is presented.

• Journal of Community Nutrition
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• v.2 no.2
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• pp.135-140
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• 2000

The objectives of this study were to determine whether older Americans would provide valid energy intake information using a 24-hr recall method and to determine which characteristics were predictive of under-report of energy intake. We conducted 24-hour recalls on 83 male and 105 female community-dwelling older adults(66-87y) in the USA to assess energy(EI) and nutrient intakes. Basal metabolic rate(BMR) was calculated from age-and gender-specific equations of Schofield. Under-reporting was defined a priori as EI : BMR<0.9. Subjects volunteered demographic information, underwent depression and cognition exams, and completed a Level II Nutrition Risk Screen. Differences between under- and adequate-reporters were assessed using t-tests for characteristics and macro-nutrient profile. Stepwise regression analyses were used to predict under-reporting status. Under-reporting of EI occurred in 34% of the sample. Neither geriatric depression scale(GDS) score, nor self-reported weight loss were related to under-reporting. On average, under-reporters had higher body mass indices. The most significant variables for the main effect to predict the ratio of energy intake to estimated basal metabolic rate(EI : BMRest) were BMI and age. Using a standard cut-off of 76% of the recommended dietary allowances for Americans, under-reporters were consistently more likely to be classified as having inadequate nutrient, as well as energy, intakes. (J Community 2(2) 135∼140, 2000)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.208-211
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• 2005

This paper presents an ultra-low partial discharge(PD) measurement system that has been accepted as a non-destructive method to estimate electrical insulation of low-voltage electric devices. The PD measurement system is composed of a coupling network, a low noise amplifier, and associated electronics. A shielding box is used to make a better condition against electromagnetic interference. A low cut-off frequency of the coupling network was 1MHz(-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 11.4mV/pC. In an application experiment on a low-voltage induction motor(5HP), we could detect 0.77pC level of partial discharge pulse at the applied voltage of AC 664 V$_{peak}$.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.3
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• pp.177-183
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• 2016

The purpose of this study was to evaluate the reliabilities of questions and diagnostic value of the Korean Sasang Constitutional Diagnostic Questionnaire(KS-15). The young adults aged 20's participated in this study. The first survey was conducted in march, 2016, and the second one was conducted two weeks later. Three hundred and three questionnaires and the informed consent were obtained from all participants. The test-retest kappa analysis was used to identify the reliabilities of the questions and diagnostic value, and the significance level was .05. The number of subjects was 303 [87(28.7%)males and 216(71.3%)females]. The Cronbach's α were .630 in 6 characteristic questions. The test-retest reliabilities of questions were ranged from .469 to 734. The agreement rate of KS-15 between the first and second constitutional diagnostic value was 87.13%(Kappa=0.794). The higher Sasang constitutional probability score in first survey resulted in the higher agreement rate between first and second diagnostic value. KS-15 seems to be a reliable implement. Further studies for the reliability of the people of different ages and suitable cut off point in Sasang constitutional probability score are needed for the practical use of KS-15.

• Parasites, Hosts and Diseases
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• v.40 no.4
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• pp.187-189
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• 2002

A 29-year-old Korean woman visited the Department of Surgery in MizMedi Hospital with a palpable itching mass on the right breast that had existed for the past 7 months. She had no history to eat either frogs or snakes, but had the history of drinking impure water. Sonography revealed a serpiginous hypoechoic tubular structure associated with partial fat necrosis in breast parenchymal layer and subcutaneous fat layer. It also revealed oval cystic lesions. At operation, an ivory white opaque ribbon-like worm that measured 16.5 cm in length and 0.5 cm in width was extracted. Anti-sparganum specific serum IgG level in the patient's serum (absorbance ＝ 0.71), measured by ELISA, was found to be significantly higher than those of normal controls (cut off point ＝ 0.21) . Sonography and ELISA appear to be helpful to diagnose sparganosis. Breast sparganosis is rarely found throughout the world.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.377-385
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• 2021

High voltage direct current(HVDC) systems has been an alternative method of a power transmission to replace high voltage alternate current(HVAC), which is a traditional AC transmission method. Due to technical limitations, Line commutate converter HVDC(LCC-HVDC) was mainly used. However, result from many structural problems of LCC-HVDC, the voltage source converter HVDC(VSC-HVDC) are studied and applied recently. In this paper, after analyzing the reactive power and output voltage ripple, which are the main problems of LCC-HVDC, the characteristics of each HVDC are summarized. Based on this result, a new LCC-HVDC structure is proposed by combining LCC-HVDC with the MMC structure, which is a representative VSC-HVDC topology. The proposed structure generates lower reactive power than the conventional method, and greatly reduces the 12th harmonic, a major component of output voltage ripple. In addition, it can be easily applied to the already installed LCC-HVDC. When the proposed method is applied, the control of the reactive power compensator becomes unnecessary, and there is an advantage that the cut-off frequency of the output DC filter can be designed smaller. The validity of the proposed LCC-HVDC is verified through simulation and experiments.