• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.631-637
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• 2005

This paper presents a stiffness analysis method for a low-DOF parallel manipulator, which takes into account of elastic deformations of joints and links. A low-DOF parallel manipulator is defined as a spatial parallel manipulator which has less than six degrees of freedom. Differently from the case of a 6-DOF parallel manipulator, the serial chains in a low-DOF parallel manipulator are subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each limb can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness model of an F-DOF parallel manipulator consists of F springs related to the reciprocal screws of actuations and 6-F springs related to the reciprocal screws of constraints, which connect the moving platform to the fixed base in parallel. The $6{times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints. The six spring constants can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; the link can be considered as an Euler beam and the stiffness matrix of rotational or prismatic joint can be modeled as a $6{times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is zero. By summing the elastic deformations in joints and links, the compliance matrix of a serial chain is obtained. Finally, applying the reciprocal screws to the compliance matrix of a serial chain, the compliance values of springs can be determined. As an example of explaining the procedure, the stiffness of the Tricept parallel manipulator has been analyzed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.34-40
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• 2006

For a cooling performance research of the combustor operated in a extreme environment of a high temperature and high pressure, we accomplished a cooling performance analysis. Generally a heat transfer characteristic in cooling passage is known well experimentally and theoretically, however heat flux in the combustion chamber isn't. In this study, fluid flow combined with heat transfer and thermal structural analysis is accomplished about a combustor nozzle. We tried to analyze the cooling performance with a heat transfer characteristic of a gas and coolant side in the view point of quantity on the mass flow rate to be supplied to the cooling channel. And finally, evaluation on the thermal and structural safety of nozzle wall material was accomplished.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.627-630
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• 2009

Ejector system can induce the secondary flow or affect the secondary chamber pressure by both shear stress and pressure drop which are generated in the primary jet boundary. Ejectors are widely used in a range of applications such as a turbine-based combined-cycle propulsion system and a high altitude test facility for rocket engine, pressure recovery system, desalination plant and ejector ramjet etc. The primary interest of this study is to set up an configuration and operating conditions for an ejector in the condition of sonic and subsonic. Experimental and theoretical investigation on the sonic and subsonic ejectors with a converging-diverging diffuser was carried out. Numerical simulation was adopted for an optimal geometry design and satisfying the required performance. Also, some ejectors with a various of nozzle throat and mixing chamber diameter were manufactured precisely and tested for the comparison with the calculation results.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.278-287
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• 2009

Ji-San, the founder of HyungSang medicine, emphasized food intake and detoxification by stating, "Korean medicine begins with detoxification." Toxin accumulates in one's body unless the internal and external conditions stay in their harmony. The accumulation of toxin is also caused by western medication or one-sided diet, and detoxification should be considered in those cases. HwangRyunHaeDok-Tang reduces fire and heat, and the lesion is likely to locate in the upper body. BangPoongTongSung-San can be used for systemic disease. IkWoon-San also reduces fire and heat but mainly focuses on promoting urination. InSamPaeDok-San has an effect of curing the external symptoms of SangHan(傷寒), in addition to detoxification. SeoGakJiHwang-Tang, SoDok-Eum, and SeoGakSoDok-Eum can resolve the heat-toxin when it is located on the surface. SibJeonDaeBo-Tang enhances the detoxifying function of human body. GhamDu-Tang and JaGeum-Jung have a general effect on detoxification.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.460-466
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• 2016

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.535-541
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• 2018

This study evaluated the sanitary state of seawater and shellfish in Yongnam-Gwangdo area from January 2014 to December 2016. The sampling stations for sanitary survey in Yongnam-Gwangdo area were composed of 41 seawater stations and 5 oyster Crassostrea gigas stations. The samples were collected monthly at each station. Shellfish-borne disease is associated with bacteria and viruses in the presence of fecal coliforms. Bacteriological pollution levels of shellfish increase with seawater quality. Therefore, fecal coliforms are very important criteria for evaluating the safety of fisheries in coastal areas. The geometric mean and the estimated 90th percentile ranges of total and fecal coliforms for seawater were 1.8-11.7, 2.8-233.6, <1.8-6.7 and 1.8-100.2 MPN/100 mL, respectively. The range of E. coli levels for oysters was <20-1,300 MPN/100 g. Based on various standards, the sanitary condition in Yongnam-Gwangdo area was evaluated as follows: clean area (Korean criteria), conditionally approved area (US criteria) and class B (EU criteria).

• Quality Improvement in Health Care
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• v.15 no.2
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• pp.83-86
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• 2009

연구배경: 수술적 치료가 필요한 척추관 협착증 환자들은 주로 60세 이상의 고령환자로 장기간의 입원 시 기회 감염의 증대와 불필요한 의료비의 증대를 가져오게 되며, 수술 후 환자들의 재원일수의 증가는 병원의 병상가동률을 감소시키고, 전공의에게는 불필요한 업무를 증가시킨다. 연구목적: 비용 효과면에서 최적화된 진료 지침의 개발은 불필요한 의료비의 감소 및 Hospital Induced Complication을 줄여 환자 만족도를 증진시킬 수 있으며, 각 환자에 대한 전공의 업무를 줄일 수 있다. 의료기관: 서울특별시에 소재한 2,075병상의 종합전문요양기관 연구방법: 정형외과 및 신경외과의 척추관 협착증 환자의 처방을 비교하여 최적의 표준진료지침을 개발하고 최종적으로 CP Master Program(EMR 프로그램)에 입력하여 환자에게 적용하였다. 연구결과: CP 적용 전, 후 비교를 통해 재원일수는 3.8일이 감소하였으며, 이에 따라 병상 가동률 및 진료수익이 증가했으리라고 예상되며 현재 비교 검토 중이다. 또한, CP 개발 및 CP Master Program의 사용을 통한 전공의 업무 감소에 대해 검토하고 있다.

• Advances in pediatric surgery
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• v.8 no.2
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• pp.107-112
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• 2002

Branchial anomaly is a frequently occurring congenital abnormality in childhood. It is important for the pediatric surgeon alike to be familiar with the embryology and differentiation of head and neck structure to accurately diagnose and treat these lesions. Eighty-five patients with branchial anomaly treated at Hanyang University Hospital between 1980 and 2001 were reviewed to determine relative frequency, clinical classification and appropriate treatment. The male to female ratio of branchial anomaly was 1.2:1. The most commonly presenting age was before 1 year (32%) and the age group between 1 and 3 year (22%) followed it. According to the classification of branchial anomalies, 73 of 85 cases were second branchial anomaly, 9 had the first type and 3 did fourth type. One patient showed combined anomalies of the first and the second type. Infection sign were seen in 70% of patients at the time of the first visit to our hospital and also patients' symptoms were frequently related with the infection. Forty-one cases (48%) were fistula, 21 (25%) were cysts, 21 (25%) were sinuses, and two were only cartilage remnants. The most common type of the branchial anomalies is the second branchial fistula and the most common symptoms of the anomalies are related with infection. Initial proper diagnosis and anatomical classification of the anomalies are very important in managing the lesions. The efforts to find the exact anatomical location of the fistula or sinus tract are necessary because total excision of the lesions including those tracts is the only way to prevent recurrence.

• Advances in pediatric surgery
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• v.8 no.2
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• pp.95-100
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• 2002

Lymphangiomas or cystic hygromas are quite commonly seen in children. During a 22-year period, from January 1980 to December 2001, 117 patients with lymphangioma were treated and followed in the Department of Pediatric Surgery at Hanyang University Hospital. The male-to-female ratio was 1.9:1(77:40) with a male preponderance. As for the age incidence at time of diagnosis, 10(8.5 %) patients were noted under 1 month of age, 37(31.6%) were between 1 month and 1 year of age, 12(10.3%) between 1 and 2 years of age, so 59(50.4%) were under 2 years of age. Sixty one (52.1%) lymphangioma-cases were located in the neck, including one case at the nape. Axilla was the second in frequency and the rest were scattered at various sites. The intrascrotal lymphangioma is very rare but we have experienced one case of primary intrascrotal lymphangioma. Eighteen (15.4%) cases were located in the intraabdominal area, 10 in the mesentery, 2 in the greater omentum and 6 in the retroperitoneum. The chief complaints of intraabdominal lymphangioma were abdominal pain, intestinal obstruction, inguinal hernia, palpable mass, and/or abdominal distension. Among 77 histologically proven cases, 14 cases were cavernous lymphangiomas and the rest were cystic lymphangiomas. Bleeding in the lymphangioma was noted in 20(17.1%) cases of all. As for the treatment, a complete excision was performed in 77(65.8%) patients and $AgNO_3$ sclerotherapy after incomplete excision was performed in 23(19.7%). Picibanil (OK-432) sclerotherapy was performed in 17(14.5%) patients. Recurrence rate was 7.7 % and mortality occurred in one case who had a large neck lymphangioma extending into the mediastinum.

• Advances in pediatric surgery
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• v.9 no.1
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• pp.1-5
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• 2003

Preauricular sinus and preauricular skin tag are common childhood congenital anomalies. It is important for the pediatric surgeon to be familiar with the embryology and differentiation of head and neck structure to accurately diagnose and treat these lesions. Seventy eight patients with preauricular sinus and twenty-eight with preauricular skin tag treated in the Department of Pediatric Surgery at Hanyang University Hospital from January 1981 to May 2002 were reviewed to determine relative frequency, clinical classification and appropriate treatment. The male to female ratio of preauricular sinus was 1:1.2, and preauricular skin tag was 1:1. The most commonly presenting age of sinus and skin tag was before 5 year (62.8%) and before 1 year (53.6%). Twenty nine of 78 cases of preauricular sinuses were on the left, 25 on the right and 24 bilateral. Signs of infection were seen in 73.0% of patients with preauricular sinus at operation. Only 31.3% of lesions were infected in patients less than one year of age, but 89.5% between 3-5 years and 100% between 5-8 years. Cartilage was present in five patients with preauricular skin tag. Although re-operation due to wound infection was necessary in four cases, no recurrences were found. The preauricular sinus is a common anomaly in childhood, and has had a relatively high recurrence rate. But most of the recurrences were due to incomplete resection because of combined infection. Initial proper diagnosis and early operation are very important. Identification of the exact anatomical location of sinus tract is necessary because total excision of the lesions including those tracts is the only way to prevent recurrence.