• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2002.04a
• /
• pp.57-58
• /
• 2002

램제트는 다른 여러 추진시스템에 비하여 획기적으로 증가된 사거리를 가지므로 가용범위의 확대는 물론, 목표물 타격 시 높은 명중률과 낮은 격추율을 가지는 효과적인 추진 시스템이다. 램제트 엔진을 장착한 미사일로는 프랑스의 Griffon, ASMP, 미국의 Bomarc, Talos, 영국의 Bloodhound, Sea dart, 소련의 SA4, SA6 등을 비롯하여 많은 종류가 개발되어 실전 배치되었다. 근래 들어 램제트는 군사전략과 전술적인 목적 이외에도 민간용으로도 그 실용성이 강조되고 있어 그 중요성은 날로 더할 것으로 예측된다. 램제트는 일반적인 공기흡입식 엔진과는 달리 엔진 내부에 기계적으로 구동되는 부분이 없이 충격파를 통과하면서 공기의 압력이 높아지는 현상인 램압축 현상을 이용하여 공기를 압축하게 되므로 엔진의 구조가 간단하고, 상대적으로 높은 비추력과 추력/중량비를 가진다. 램제트는 정지 상태에서는 작동되지 않으며 사용 가능한 최소의 압력비를 줄 수 있는 비행 마하수에 도달해야 램제트가 작동하게 된다. 따라서 이러한 비행속도를 줄 수 있는 별도의 추진장치가 필요하게 되는데 이와 같은 보조 추진장치로 부스터를 사용한다. 부스터가 엔진의 내부에 장착된 램제트를 일제형 램제트 (IRR: integral Rocket Ramjet)라 부르며, 현대의 전략미사일과 민간용 초음속 항공기의 엔진에 도입되어 활발한 연구가 진행 중이다. 램압력을 이용하여 압축하므로 램제트의 설계시 설계점 비행 속도에서 전압력 손실이 최소가 되도록 설계되어야 하며, 이를 실험이나 수치해석을 통해 확인하여야 한다.

• Journal of Labour Economics
• /
• v.33 no.3
• /
• pp.129-149
• /
• 2010

We find that there is the height premium in the Korean labor market. The wage increases by 1.5% with a centimeter increase of height among male workers of ages 30-49. This estimate is barely affected by family backgrounds such as a worker's father's education or occupation. It is rejected that a worker's height is a proxy variable for his health, which increases his wage. The height premium is unrelated with obesity. It is not also supported that a worker's height affects his wage through his occupational choice. We partly confirm that a worker's height affects his wage through his educational choice. The estimated height premium of 30's in Korea is comparable to that of age 33 in Great Britain.

• Journal of the Korean Society for Railway
• /
• v.12 no.1
• /
• pp.151-160
• /
• 2009

Recently, the importance of rail in the carriage of freight is strongly emphasized. However, the role of rail in the carriage of freight has been decreasing. The purpose of this study is to suggest policy measures for increasing rail freight. Firstly, this study reviews the current situations of the rail freight in Korea and provides theories for the necessity of government support to rail freight transport. Various support measures are identified and evaluated. According to the evaluation, it is shown that the provision of subsidy for facility construction is the most desirable measure in the sense of cost effectiveness and durability of effect. Finally, detailed implementation strategies for the desirable support measures are suggested.

• The Microorganisms and Industry
• /
• v.10 no.1
• /
• pp.2-6
• /
• 1978

백신이란 학문의 원조는 고금 동서를 불문하고 영국의 Jenner라는 것은 우리가 잘아는 사실이다. 이것은 약 200년전의 일이며 그후 각종 전염병예방 백신이 개발되어 오늘날 우리인간은 예전ㅇ 비해 각종 전염병에 대해 큰 은혜를 받고 있는 셈이다.특히 1949년 미국의 Enders박사 일맥의 조직 배양의 개량법에 의한 바이러스의 대량 배양과 정제및 농축이 용이하게 된것은 백신생산 개발문제뿐만아니라 바이러스학과 전염병 예방학의 발전의 일대혁신을 가져왔으며 세균학에 있어서 Koch의 고형배제를 사용하여 많은 병원성세균의 발견을 하게된 것과 비슷한 느낌을 준다. Enders의 조직배양의 modern technique는 아직까지 원인불명인 여러 종류의 바이러스 전염병 병원체가 구명되었으며 지금도 계속 새로운 바이러스가 발견되고 있는 중이다. 그 대표적인 예를 들면 폴리오(Polio)를 중심으로 Coxsackie virus의 A및 B군과 ECHO virus등 장관계바이러스들의 발견과 그 체계적정비 그리고 Adeno virus를 위시한 호흡기계 바이러스들의 계속적인 발견과 그 실험실진단법의 확립등을 들수 있다. 한편 백신개발에 대한 확립 등을 들수있다. 한편 백신개발에 대한 발자취를 보면 폴리오를 위시하여 홍역(Measles)백신, 멈프스(Mumps)및 풍진 (Rubella virus) 백신등의 개발은 근래 선,후진국을 막론하고 이러한 전염병의 예방효과가 눈에 띠게 덕을 보고있는 것이다. 지금 세계적으로 많은 전염병의 병원체가 바이러스라는 것이 알려져 있고 또한 이에 대한 백신의 개발연구가 활발하게 진행되고 있다. 이번 기회에 바이러스백신의 전망이라는 제목을 가지고 논하게 된것을 기쁘게 생가하며 동시에 어려운 과제라고도 생각된다. 왜냐하면 아직 우리나라에서는 생산을 못하고 있는것이 많은데 그 전망을 말하기가 어려운 까닭이며 또한 제한된 지면에서 충분히 고찰하기는 어렵다. 우리나라에서 자주 거론되는 백신 및 종류에 국한하여 그 문제점과 앞으로의 전망을 고찰해 보기로 한다.

• Advances in pediatric surgery
• /
• v.13 no.1
• /
• pp.66-71
• /
• 2007

There have been no definitive preoperative diagnostic imaging studies for impalpable testes. We observed the effectiveness of laparoscopy for detecting impalpable testes not identified with ultrasonography (USG) or careful physical examination under general anesthesia. We retrospectively reviewed 117 patients (118 testes) who were operated upon for undescended testes from January 1998 to December 2004. The testes of these patients were palpable in 97(82 %) and impalpable in 21 (18 %). We analyzed the preoperative diagnostic method, site of the testes, operative method and operative findings of the 21 impalpable testes. Preoperative USG and physical examination under general anesthesia were performed on 20 patients, and 12 patients' testes could be localized. Eight patients whose testes could not be localized with USG and physical examination underwent laparoscopy. Seven of the 8 patients had testes in inguinal canal and 4 of these were atrophied and underwent orchiectomy because of atrophy (2) and vanishing (2). Only 1 patient had bilateral intraabdominal testes and one of the testes was atrophied. Laparoscopy was a useful method for detecting impalpable testes, but the clinical application might be limited because the location of atrophic or vanishing testes was mainly inferior to internal inguinal ring.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.26 no.1
• /
• pp.391-428
• /
• 2015

This research aims to seek for activation methods of archive events regarded as one of the ways of recording information service, in order that the national archives which needs to change its role meets various users. In order to reach the goals I have suggested, I have compared the examples of archive events operated at the National Archives and Records Administration (NARA, the United States of America, USA) and The National Arc-hives (TNA, the United Kingdom, UK) to the case of archive events at the National Archives of Korea (NAK). As a result, I have proposed activation methods as follows based on those; subdivision of the detailed subject area, diversification of the programmes types, and connectivity reinforce of archive events.

• The Journal of Korean Association of Computer Education
• /
• v.8 no.5
• /
• pp.97-108
• /
• 2005

In this paper, we present our prototype of a web manual creator that is based on MSP technology embedded in webMathematica. This tool gives courseware authors more simple ways to make their own mathematical web contents. We first classified authoring models for creating mathematical content development and proposed an advanced model. The final application called phpMath can generate MSP-driven documents automatically using Mathematica commands typed by users. In other words, phpMath users can make interactive dynamic mathematical web contents even though they do not know anything about web server, HTML, and webMathematica. We illustrated the details of the prototype from the user's perspectives followed by comments on usefulness.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2005.03a
• /
• pp.831-837
• /
• 2005

In this study, a computer program to predict the behavior of laterally loaded single pile and pile groups was developed by using a beam-column analysis in which the soils are modeled as nonlinear springs by a family of p-y curves for subgrade modulus. The special attention was given to the lateral displacement of a single pile and pile groups due to the soil condition and the cap rigidity. The analysis considering group effect was carried out for $2\;{\times}\;2\;and\;3\;{\times}\;3$ pile groups with the pile spacing 3.0B, 4.0B and 5.0B. Based on the results obtained, it is found that the overall distributions of deflection, slope, moment, and shear force in a single pile give a reasonable results irrespective of cap connectivity conditions. It is also found that even though there are some deviations in deflection prediction compared with the observed ones, the prediction by present analysis simulates much better the general trend observed by the centrifuge tests than the numerical solution predicted by PIGLET.

• Convergence Security Journal
• /
• v.6 no.4
• /
• pp.121-132
• /
• 2006

Every country of the world have made their desirable future by improving the methodology of technology forecasting with priority, selection and concentration, despite the limited budget. About 20 years have passed since Defense S&T forecasting has been initiated but supplier-centered technology forecasting has caused the lack of usefulness for the customers. Therefore, we will search and offer technologies that customers need, based on the methodology of technology foresight that has started in England. It is a real value of Defense S&T forecasting that will help our nation, a smaller and weaker country compared to our neighboring countries, has a secure future and prosperity. For this consideration, 8 directions of the development for Defense S&T forecasting are suggested.

• Survey Research
• /
• v.3 no.1
• /
• pp.91-118
• /
• 2002

Korean election polls has a history of fifteen years, which may seem too short while those of advanced countries such as the U.S and the UK has a history of one hundred fifty years. However, with various and creative attempts, some of the Korean research companies have developed election polls methods and theories which can be applied to Korean society. They also elevated accuracy of the election forecasts. In spite of short history the rational and scientific polls and forecasts done by some of the research companies including Gallup Korea are commented that they have improved the quality of Korean election culture. In the article, we will look into the process of the election polls which have been done seven times for 15 years, and then deal with the meaning of the election polls.