• The KSFM Journal of Fluid Machinery
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• v.7 no.2 s.23
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• pp.21-26
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• 2004

In this study the effects of fluid viscosity on the pump performances for a conventional centrifugal pump were experimentally investigated. The study aimed to compare the pump characteristics between water and viscosity fluids. In order to measure the flow rate and pressure, v-notch welt and bourdon pressure gauges were used for the codes of KS B6301 and KS B6302. The working fluids were water, aqueous sugar and glycerin solutions. The results were summarized as follows : The experimental results were summarized as follows : the pump characteristics of the total head, shaft power, and efficiency with high viscosity fluids were different from those of water. When the viscosity of the applied fluid was increased, the total head and efficiency were more decreased than those of water. The decreasing gradients of the total head and the efficiency were larger than water due to the increased disk friction losses at the duty operation point. However, the shut-off head was almost constant regardless the viscosity of applied fluids. Each efficiency curves for the sugar $20w\%$ and glycerin $20w\%$ solutions was decreased up to $15.1\%$ and $34.4\%$ than that of water, respectively.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.165-170
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• 2001

An extensive range of pumping facilities are employed in the regional water supply system in metropolitan areas, and optimization and the systematic combination of the Pump facilities have direct bearing on the stability and economy of the water supply system concerned. These systems must be able to guarantee stability, efficiency and offer high reliability. Preparation of metropolitan area regional water supply system construction project must include a basic plan which takes into account the suitability of pumping facilities to be used, the environment in which facilities will be installed, man-power requirements and basic operational and management policies. This paper contains over-all analysis of the management of metropolitan area regional water supply systems as like Jayang, Paldang 1st pump station. In the study, it aims to prepare counterplan which will be operated and managed the pump upon the operational conditions and to suggest the proposal for water facilities codes to decides total head of pump in Korea.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.55-65
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• 1996

This study was performed to investigate the effects of head posture and occlusal splint on the vertical dimension in mandibular rest position and swallowing. Thirty health dental students ware selected lot this study and BioEGNⓡ(Bioresearch Inc., USA) was used for measuring interocclusal distance during rest - swallowing - rest - tapping movement. This swallowing movements were observed in both normal head posture(NHP) and forward head posture (FHP). Thickness of occlusal splint was about 2mm at posterior molar area and even tooth contact were achieved on light biting. The four mandibular positions at which interocclusal distance measured were swallowing position, after swallowing position in which interocclusal distance was maximum, rest position follows swallowing, and tapping position after rest. Changes of distance in each position were measured for three mandibular planes, that is, sagittal, frontal, and horizontal plane, respectively. The results obtained were as follows : 1. In normal head posture, the mandible was raised 1.03mm without splint, and 0.77mm with splint on swallowing, and there was no significant difference between the two. In horizontal plane, however, mandible was displaced more anteriorly in both swallowing position and tapping position with splint. 2. In forward head posture, the mandible was less raised with splint on swallowing, but features in horizontal plane were almost same as those in normal head posture. 3. In natural dentition, significant difference between NHP and FHP were observed in horizontal plane trajectory for swallowing and tapping position. But the difference for same positions were observed in frontal trajectory with splint. 4. Total amount of mandibular movement of two groups classified with sagittal interocclusal distance of swallowing position generally showed significant difference between the higher and the lower height group in head posture without splint. 5. Correlationship among total amount of mandibular movement for three mandibular planes were observed between sagittal plane and horizontal plane, and between sagittal plane and frontal plane in head posture without splint.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.60 no.10
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• pp.504-511
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• 2017

Background and Objectives In this study, we evaluated differences in the prevalence of allergic rhinitis, asthma, atopic dermatitis and specific immunoglobuline E (IgE) value for some respiratory antigens in Korean adults. Subjects and Method The study was conducted using data from the 5th National Health and Nutrition Survey (2010-2012). All subjects who were aged 19 years or older completed questionnaires on asthma, atopic dermatitis and allergic rhinitis. The subjects were first divided into male and female, and then into age groups of 19-29, 30-39, 40-49, 50-59, 60-69, ${\geq}70$ each. The lifetime and current prevalence rates for allergic rhinitis, asthma, and atopic dermatitis were calculated for each age group. The total and specific IgE level for Dermatophagoides farinae (DF), cockroach, and dog dander were also calculated. Results Final participants of 17542 were analyzed for the prevalence rate among the total of 25534 participants. The mean IgE level was calculated from 2028 subjects from the final participants. In asthma, the lifetime prevalence and current prevalence increased with age, but decreased with atopic dermatitis and allergic rhinitis. Total IgE level increased with age, but IgE level of DF reached its peak at 20-29 years, and then decreased rapidly thereafter. There was no clear trend for cockroach and dog dander. Conclusion The prevalence of allergic diseases in adults varies widely by age group. Asthma has a low prevalence after age 20 and gradually increases after age 50. Atopic dermatitis and allergic rhinitis are the most prevalent in their 20s and gradually decrease thereafter.

• Korean Journal of Bronchoesophagology
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• v.4 no.1
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• pp.91-95
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• 1998

Background： Laryngeal cancer, the most common malignancy of head and neck, is being detected and treated in earlier and more effectively due to introduction of endoscope, continuous development of radiographic technology, and advancement in new surgical techniques such as laser surgery and conservation laryngeal surgery Objectives To compare the different treatment results for early laryngeal cancer to determine which methos provides the good prognosis. Materials and Methods： Retrospective study was done for 135 patients with early laryngeal squamous cell carcinoma(Stage I or II) who were treated at our institute between 1989 to 1996. There were 105 patients with glottic cancer(Stage I: 68 patients, Stage II：37 Patients) and 30 patients with supraglottic cancer(Stage I: 12 patients, Stage II：18 patients) Initial treatment included radiation therapy for 54 patients, endoscopic laser surgery for 8 patients, laryngofissure and cordectomy for 8 patients, vertical partial laryngectomy for 37 patients, supraglottic laryngecomy for 14 patients and supracricoid laryngectomy for 5 patiens, and total laryngectomy for 9 patients. Results : Salvage treatments, such as total laryngectomy, conservation laryngeal surgery, radiation therapy and neck dissection were performed for initial treatment failure with 9 patients after radiation therapy, 8 patients after conservation laryngeal surgery, 2 patients after endoscopic laser and 3 patients after total laryngectomy. Overall 3-year survival rate for glottic 71 was 92.4%, glottic f 84.3%, supraglottic 7172.7%, and supraglottic f was 63.%%. However, survival rate of the same stage was variable according to the choice of initial treatment. Conclusion New classification of the early laryngeal cancer was necessary and helpful for the choice of the initial treatment.

• Safety and Health at Work
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• v.15 no.1
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• pp.42-52
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• 2024

Background: The lack of headforms that accurately reflect the head characteristics of Koreans and the demographic composition of the Korean population can lead to inadequate FFR testing and reduced effectiveness of FFRs. Method: Direct measurements of 5,110 individuals and 3D measurements of 2,044 individuals, aged between 9 and 69 years, were sampled from the data pool of Size Korea surveys based on the age and gender ratios of the Korean resident demographics. Seven head dimensions were selected based on the ISO 16976-2, availability of Size Korea measurements, and their relevance to the fit performance of FFRs. A principal component analysis (PCA) was performed using the direct measurements to extract the main factors explaining the head characteristics and then the main factors were standardized and remapped to 3D measurements, creating five size categories representing Korean head shapes. Lastly, representative 3D headforms were constructed by averaging five head shapes for each size category. Results: The study identified two main factors explaining Korean head characteristics by the PCA procedure specified in ISO 16976-2 and developed five representative headforms reflecting the anthropometric features of Korean heads: medium, small, large, short & wide, and long & narrow. Conclusion: This study developed representative headforms tailored to the Korean population for conducting total inward leakage (TIL) tests on filtering facepiece respirators (FFRs). The representative headforms can be used for TIL testing by employing robotic headforms to enhance the performance of FFRs for the Korean target population.

• Journal of Family Resource Management and Policy Review
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• v.22 no.1
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• pp.63-78
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• 2018

This study examined the insolvency of debtors using multiple-indicator approaches and compared the outcomes across income levels with the 2016 'Household Financial and Welfare Survey'. This study used (1) the total debt to total assets ratio (DTA), (2) the total debt service ratio (DSR), and (3) the Household Default Risk Index (HDRI) recently developed by the Bank of Korea. Households in the lowest income quintile were more likely to be insolvent than any other income group. Demographics, such as age and gender of the household head, and most of the financial variables significantly increased the likelihood of insolvency based on the DTA. The number of household members and job status increased the likelihood of insolvency based on the DSR. Also, age, gender of the household head, and most of the financial variables increased the likelihood of household insolvency based on the HDRI after controlling for other demographics and financial variables.

• Korean Journal of Rural Living Science
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• v.9 no.1
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• pp.43-54
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• 1998

This study attempted to investigate the factors affecting financial status of the rural middle-aged and old-aged household. The results shelved that the significant variables which influenced on the probability of financial security measured by consumption to income ratio were sex and education level of the household head, family size, total income, total expenditure and total assets. The most influential variables on the probability of financial security measured by liquidity ratio was liquid assets, and total assets. Education level of the household head. liquid assets, total assets, and total debt had significant effects on the probability of financial security estimated by debt burden ratio. Among the economic variables, only liquid asset had significant negative effects on the probability of financial security assessed by the capital stock ratio.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.1
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• pp.43-50
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• 2021

This study aims to investigate and analyze the utilization perception of members of head families based on a survey on the history, folklore, architectural resources of head families. In order to identify the direction of utilization of Jeonnam head family resources, tangible and intangible resources, and spaces and places to contain programs were researched. The results of the study were summarized as follows. 1) Head family houses in Jeonnam could be categorized into head families that preserved the original form of head family houses, head families that preserved a part of head family houses, head families that newly built head family houses while the original forms thereof have disappeared, and relocated head families of which eldest grandsons no longer reside, where only the sites of the head family houses remain or relocated to a different place. 2) In the case of perception of members of head families on the utilization of head family resources, 27 head families consented to the utilization, 35 head families opposed to the utilization, and 6 head families were undecided on the utilization out of a total of 68 head families. 3) The results of investigating and analyzing the desired type of programs of each head family by categorizing the programs into lodging, food, meditation, education, and tourism, as many as four programs were desired, while some families desired 2 or 3 programs at the lowest, showing an overlapping characteristic.

• The Research Journal of the Costume Culture
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• v.12 no.6 s.53
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• pp.1021-1030
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• 2004

The purpose of this study was to develop and make the head form by setting the region of the head for detailed measurement of the head to make the type of closely fit hat and typifying the head form of Korean women's with each region of the head based on the measurements of each region of the head according characteristics. A total of 285 Korean women's in the age group of 18 to 35 years old. It were measured through the direct measurement method by selecting 67 measurement items. As a result of the findings obtained from cluster analysis could be classified into 3 type. Type 1($46\%$) is U-shaped form, that is high in head height on sides and circumference is smallest, whose facial region and occiput is flattest of three types. Type 2($22.4\%$) is inverted triangle form, that is flat in head ridge, low in head height on sides and wide in the frontal width. Type 3($31.6\%$) is oval form, that is largest in size, has the projected occiput and is of three-dimensional form.