• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1987.05a
• /
• pp.17.3-18
• /
• 1987

식도이물은 이비인후과영역에서 흔히 접하는 질환이며, 그 예는 국내외를 막론하고 대단히 많은 보고가 있는데, 그 종류도 다양하여 지역, 시기, 민족, 생활환경, 생활양식, 개인의 습관, 오락, 취미 등에 따라 각양각색이다. 대부분의 식도이물은 식도경하에서 적출이 가능하지만, 특별한 경우에는 외과적 수술에 의해서만 적출이 가능하다. 최근 저자들은 양고기 뼈(절단된 관절 연골부)가 식도 제삼 협착부에 수평으로 체류하여 식도 직달경 하에서 여러가지 감자로 적출을 시도하였으나 실패하여, 외과적 수술로 적출한 1례를 경험하여, 이에 문헌적 고찰과 함께 보고하는 바이다.

• Journal of Korean Library and Information Science Society
• /
• v.36 no.4
• /
• pp.177-198
• /
• 2005

The objective of this paper is to obtain the knowledge for spatial Planning of children's library which serves various users. The study method is to observes the children and their parents' space use according to the age step of children in public library, and analyzes it in the relation with the classified 4-types of children's section. Five characteristics were identified. First, children area was influenced by library location and user's characteristics. Second, children area was used various aged group with children. Third, there were different use patterns based upon age. Fourth, various reading space was needed through areas. And, last the behavior and the characteristics of area and furnishings were described.

• KSBB Journal
• /
• v.7 no.1
• /
• pp.59-65
• /
• 1992

Hydrodynamics and mixing characteristics such as circulation time, mixing time, circulation velocity and axial dispersion coefficient were investigated using highly viscous pseudoplastic solutions of carboxymethyl cellulose(CMC) in an external circulation loop air-lift reactor with 13$\ell$ working volume. The superficial gas velocity was changed from 1.9 to 6.2cm/s and CMC concentration from 0 to 1.0wt%. The theoretical model based on the pressure balance is developed mathematically to predict liquid circulation velocity. Gas hold-up, circulation velocity and axial dispersion coefficient of liquid phase increased with increasing gas velocity and decreased slightly with increasing liquid viscosity. Mixing time and circulation time decreased with increasing gas velocity and increased with increasing liquid viscosity. Experimental data on liquid circulation velocity were in good agreement with the predicted values.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1982.05a
• /
• pp.11.1-11
• /
• 1982

Foreign bodies in the esophagus is a common problem encountered in the ENT field. Small toys were the most common type of esophageal foreign body found in Korea until the government started making coins. Although 10 won coins are most commonly found, there is a tendency for an increased percentage of 100 won coins parallel with the economic development of the country. Recently, the authors experienced a very intersting case in which a 7 year-old child had a 5 won coin lodged horizontally at a level of the third esophageal constriction portion for 4 years, which eventually resulted in esophageal dilatation. A review of the literature of this subject is included.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2002.05a
• /
• pp.136-143
• /
• 2002

이동 통신망에서 호의 연결 기능를 수행하기 위해서는 이동체(Mobile Terminal)의 위치를 추적할 수 있어야 한다. 이러한 위치추적은 이동체에 의해 수행되는 위치등록과 기지국에 의해 수행되는 페이징에 의해 이루어진다. 하나의 기지국이 담당하는 영역은 셀이라 불리며. 이러한 여러 개의 셀들이 하나의 영역(Zone 흑은 Location Area로 표현됨)을 형성하여 특정의 이동체가 주어진 영역을 벗어나면 위치등록을 하게 되고, 따라서 이 이동체에게 새로운 호가 발생할 때 그 이동체가 최종적으로 등록한 영역에 있는 모든 셀에 페이징 메시지를 보냄으로써 호의 연결이 이루어지는 것이다. 양자는 서로 상쇄관계에 있으며. 양자간의 적절한 부하를 도출하는 것을 이동성 관리(Mobility Management)라고 한다. 기존의 논문에서는 이동성 관리를 위해 이동체의 이동성 모형을 단순히 호 발생률과 이동체의 이동률의 비를 기준으로 분석하였으나, 이것은 연속적인 이동상태나 장기 정지/이동의 패턴은 보여주지 못하고 있다. 본 논문에서는 셀 체류시간의 분포를 다르게 하여 장기정지 상태와 이동 상태가 반복되는 새로운 이동성 모형을 제시하며, 이를 바탕으로 거리기준 위치등록의 최적 기준치를 새로이 도출하며 분석의 결과를 기존 논문과 비교하여, 그 의미를 탐색하고자 한다.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2002.11a
• /
• pp.529-534
• /
• 2002

출입 관리는 위조 여권 소지자, 수배자, 출입국 금지자 또는 불법 체류자 등의 출입국 부적격자를 검색하고 출입국자를 관리하기 위하여 행하여진다. 한편, 여권에는 사진, 국적, 성명, 주민등록번호, 성별, 여권번호 등을 포함한 정보들로 이루어져 있다. 이러한 출입국 관리 시스템은 출입국 심사 시간이 길어 출입국자에게 불편이 따르고 또한 출입국 부적격자에 대한 정확한 검색이 불분명하여 체계적으로 관리하기가 어렵다. 이러한 종래의 문제점을 개선하기 위해 영상 처리와 문자 인식을 이용한 여권 인증 시스템을 제안한다. 본 논문에서는 여권 영상에 대해 소벨 연산자와 스미어링 기법 그리고 윤곽선 추적 알고리즘을 이용하여 사진영역, 코드 영역 및 개별 코드 문자를 추출하였다. 추출된 개별 코드 인식은 ART2 알고리즘을 기반으로 한 RBF 신경망을 제안하여 여권 인식에 적용하였다. 제안된 방법의 성능을 확인하기 위해서 실제 여권 영상들을 대상으로 실험한 결과, 제안된 방법이 여권 인식에 우수한 성능이 있음을 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.10
• /
• pp.1294-1299
• /
• 2000

The combustion characteristics have been investigated to develop the 50 kW-class gas turbine combustor. The combustor design program was developed and applied to design this combustor. The combustion air which has the temperature of 45, 200, $300^{\circ}C$ were supplied to combustor for elucidating the effect of inlet air temperature on CO, NOx emissions and flame temperature. The exit temperature and NO were increased and CO was decreased with increasing inlet air temperature. Also, the effect of equivalence ratio was considered to verify the combustor performance. The emissions of CO and NO with inlet air temperature can be analyzed qualitatively by measuring the temperature inside the combustor. The combustion performance with fuel schedule was evaluated to get the informations of the starting and part loading process of gas turbine. The combustion was stable above the equivalence ratio of 0.18. The pattern factor which is the important parameter of combustor performance was satisfied with the design criterion. Consequently the combustor was proved to meet the performance goal required for the target gas turbine system.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.7
• /
• pp.1074-1081
• /
• 2021

Nitrous oxide (N₂O) is one of the six major greenhouse gases and is known to produce a greenhouse ef ect by absorbing infrared radiation in the atmosphere. In particular, its global warming potential (GWP) is 310 times higher than that of CO₂, making N₂O a global concern. Accordingly, strong environmental regulations are being proposed. N₂O reduction technology can be classified into concentration recovery, catalytic decomposition, and pyrolysis according to physical methods. This study intends to provide information on temperature conditions and reaction time required to reduce nitrogen oxides with cost. The high-temperature ranges selected for pyrolysis conditions were calculated at intervals of 100 K from 1073 K to 1373 K. Under temperatures of 1073 K and 1173 K, the N₂O reduction rate and nitrogen monoxide concentration were observed to be proportional to the residence time, and for 1273 K, the N₂O reduction rate decreased due to generation of the reverse reaction as the residence time increased. Particularly for 1373 K, the positive and reverse reactions for all residence times reached chemical equilibrium, resulting in a rather reduced reaction progression to N₂O reduction.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.4 no.4
• /
• pp.78-86
• /
• 2000

The objective of this research is to understand the characteristics of a nonpremixed, turbulent, hydrogen jet flame which is stabilized in Mach 1.8 coflowing air flows. In order to investigate the flame structure, flame lengths and fuel trajectories were measured by using direct photography, acetone PLIF, Mie scattering techniques, and numerical simulation. Effect of increasing air velocity was investigated when fuel velocity is fixed. The subsonic flame length was decreased drastically, however the supersonic flame length was increased slowly Then the change of flame blow out characteristics was observed as varying fuel nozzle lip thickness. The flame stability can be increased when fuel nozzle lip thickness was increased, which indicates that the minimum fuel lip thickness ratio is required for the stable supersonic flames. Also, it is found that fuel jet is blocked by high pressure zone and low scattering zone is made. Then the fuel that was moving along the recirculation zone had longer residence time within the supersonic flames, which made partially premixed zone.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.5
• /
• pp.971-980
• /
• 2000

Mixed methanotrophs (MM) secreting soluble methane monooxygenase(sMMO) were immobilized on celite R-635 to degrade trichloroethylene(TCE) in methanotrophic consortium biofilm reactor(MCBR) system. Further neutralization of celite R-635 was not needed for immobilization because effluent pH was stabilized at neutral after 4 hour washing. It took 130 days to develop biofilm on celite R-635 and the color of the celite changed gradually from white to red. After biofilm developed, influent methane and oxygen were decreased from 2.5~4 and 8~10 ppm to 0.5~1 and 1~2 ppm, respectively, With influent 2 ppm of TCE and 10 hours of retention time, 79.9% of TCE was degraded in the MCBR system.