인간의 비행 가능성에 대한 경험적 증명

이 논문은 19세기 말 미국 스미스소니언의 협회장이자 천체물리학자, 항공학 개척자였던 새뮤얼 P. 랭글리(1834-1906)의 항공학을 19세기 비행 이론 발전의 역사 속에서 재조명한다. 랭글리의 항공역학 저작인 『항공역학 실험들』(1891), 「바람의 내적 작용」(1893)을 그가 참고한 프랜시스 웬햄, 알퐁스 페노 등 19세기 항공학자들의 비행에 대한 이론적 논의를 바탕으로 분석한다. 이를 통해 랭글리의 항공학은 인간처럼 무거운 물체가 새처럼 비행할 수 없다는 물리학의 지배적인 견해를 비판하고, 비행 기계의 개발 가능성을 증명하려는 목적을 갖고 수행되었음을 주장한다. 이때 랭글리가 이전의 유럽 항공학자들과 차별을 두기 위해 유체역학과 다른 새로운 학문으로서 항공역학을 제안하고 있었으며, 그러한 항공역학은 비행기라는 아직 실현되지 않은 기술에 관해 다루는, 철저히 실험적 토대 위에 세워져야 하는 학문으로 주장되고 있었음을 이야기한다. 이러한 논의를 통해 항공역학이라는 학문이 다른 가능성을 갖고 잉태되고 있었음을 주장한다. 이 논문은 또한 에어로드롬 연구에 있어 과학적 측면을 강조했던 랭글리의 ‘에어로드롬학’을 중심으로 그의 에어로드롬 개발 과정을 살핀다. 그리고 랭글리가 경험주의적 방법론의 강조로 인해 공학자적인 인식론으로 충분히 나아가지 못하였던 것이 그레이트 에어로드롬의 실패 요인 중 하나였음을 제안한다. 그러나 그 실패에도 불구하고 랭글리의 과학과 에어로드롬이 미국 항공학자 사회에서 지녔던 중요성을 설명하고자 하며, 이를 위해 랭글리 항공학의 과학적, 기술적 탁월함보다는 그것이 가졌던 비행기에 대한 낙관적 전망에 주목해야 함을 주장한다. 랭글리의 항공역학의 대표적 성과로 언급되는 ‘랭글리 법칙’은 당시에는 유망하게 여겨지지 않았던 비행기라는 기술의 개발 가능성을 증명하는 원리로서 제안되었으며, 랭글리의 무인 비행기인 에어로드롬 No. 5~No. 6의 성공은 그러한 비행의 실현 가능성 증명을 완수하는 의미를 가졌다. 또한 초기 미국 항공학자들 사이에서도 랭글리의 과학은 비행기 개발의 가능성을 ‘과학적으로’ 증명하는 것으로 인식되었으며, 이로써 랭글리는 미래의 교통수단으로서 비행기에 대한 전망을 이끌고 있었다. 이러한 랭글리의 과학은 후대 항공학자들이 그레이트 에어로드롬의 비행 능력을 주장하는 데에도 영향을 미쳤다.This paper locates the aeronautics of Samuel P. Langley(1834-1906) in the history of the development of flight theories in the 19th century. It especially deals with Langley's Experiments in Aerodynamics (1891) and "Internal Work of the Wind" (1893) in relation of the theories of flight of Francis Wenham and Alphonse Pénaud. Langley's aeronautics was carried out with a purpose of proving the possibility of mechanical flight, overturning the prevailing view of physics that an object as heavy as a human cannot fly like a bird. 'Langley's Law' was itself a demostration of the practicability of airplane, and the successful flights of the Aerodrome No. 5, No. 6 were thought of as the completion of his demonstration. In the course of that, Langley was claiming a new discipline of “aerodynamics” other than fliuid dynamics, which deals with the yet unrealized technology of airplanes and should be built on a thoroughly empirical foundation. His claim for “aerodynamics” can be understood as a strategy to differentiate himself from previous European aviation pioneers. Langley's 'Aerodromics,' which emphasized the scientific aspect of aerodrome research, were however ineffective in designing the Aerodromes, and ultimately led to the failure on December 8, 1903. His emphasis on empiricism was not effective on dealing with real engineering design problems. However, Langley's aerodynamics and his aerodromes still had important meanings in the early American aeronautical society. Langley's aeronautics should be valued not for his scientific skills or proficiency, but for its optimistic power to realize an undeveloped technology. Langley's science was perceived as "scientific" proof of the practicability of airplanes among the early American aviation pioneers, and his prospect of airplanes as both future public vehicles and engines of war was shared by them. It was quite different from the European opinion.1. 서론 1 2. 19세기 비행에 관한 역학적 문제의 대두 13 3. 랭글리의 '항공역학'과 랭글리 법칙 29 3.1. 항공역학 실험들과 랭글리의 '항공역학' 32 3.2. 공학 과학으로서의 항공역학 50 3.3. 항공역학 실험들에 대한 레일리의 비판과 바람의 내적 작용 56 4. 에어로드롬과 과학 66 4.1. 과학적 탐구 대상으로서의 에어로드롬 69 4.2. 항공역학이 반영된 에어로드롬 설계의 문제 73 4.3. 그레이트 에어로드롬의 실패 85 5. 결론 101 참고문헌 105 Abstract 112석

Monitoring of Motor and Somatosensory Evoked Potentials During Spine Surgery: Intraoperative Changes and Postoperative Outcomes

OBJECTIVE: To evaluate whether the combination of muscle motor evoked potentials (mMEPs) and somatosensory evoked potentials (SEPs) measured during spinal surgery can predict immediate and permanent postoperative motor deficits. METHODS: mMEP and SEP was monitored in patients undergoing spinal surgery between November 2012 and July 2014. mMEPs were elicited by a train of transcranial electrical stimulation over the motor cortex and recorded from the upper/lower limbs. SEPs were recorded by stimulating the tibial and median nerves. RESULTS: Combined mMEP/SEP recording was successfully achieved in 190 operations. In 117 of these, mMEPs and SEPs were stable and 73 showed significant changes. In 20 cases, motor deficits in the first 48 postoperative hours were observed and 6 patients manifested permanent neurological deficits. The two potentials were monitored in a number of spinal surgeries. For surgery on spinal deformities, the sensitivity and specificity of combined mMEP/SEP monitoring were 100% and 92.4%, respectively. In the case of spinal cord tumor surgeries, sensitivity was only 50% but SEP changes were observed preceding permanent motor deficits in some cases. CONCLUSION: Intraoperative monitoring is a useful tool in spinal surgery. For spinal deformity surgery, combined mMEP/SEP monitoring showed high sensitivity and specificity; in spinal tumor surgery, only SEP changes predicted permanent motor deficits. Therefore, mMEP, SEP, and joint monitoring may all be appropriate and beneficial for the intraoperative monitoring of spinal surgery.ope

The Nutritional Status and the Clinical Outcomes of Patients With a Spinal Cord Injury Using Nutritional Screening Tools

OBJECTIVE: To assess the nutritional status of Korean patients with spinal cord injury (SCI), identify the predictors of undernutrition, and investigate the relationship between undernutrition and clinical outcomes. METHODS: A retrospective study design was used to determine the nutritional status of 130 patients over 19 years old admitted to the rehabilitation hospital of Yonsei University Health System between June 2015 and February 2017. The nutritional status was assessed using the malnutrition universal screening tool (MUST) and the spinal nutrition screening tool (SNST). The relationship between undernutrition and clinical outcomes was examined by comparing a low-risk group with an at-risk group using a t-test. RESULTS: Among the SCI patients, 70 (50.8%) were confirmed with undernutrition based on the MUST scores, while 60 (46.2%) had undernutrition based on the SNST scores. It was found that undernutrition has an effect on functional outcomes. CONCLUSION: We assessed the undernutrition risk in Korean SCI patients, and found that approximately 50% of the patients were at risk of undernutrition. We also found that undernutrition can affect functional recovery.ope

Effect of Patient Education on Reducing Medication in Spinal Cord Injury Patients With Neuropathic Pain.

OBJECTIVE: To determine whether providing education about the disease pathophysiology and drug mechanisms and side effects, would be effective for reducing the use of pain medication while appropriately managing neurogenic pain in spinal cord injury (SCI) patients. METHODS: In this prospective study, 109 patients with an SCI and neuropathic pain, participated in an educational pain management program. This comprehensive program was specifically created, for patients with an SCI and neuropathic pain. It consisted of 6 sessions, including educational training, over a 6-week period. RESULTS: Of 109 patients, 79 (72.5%) initially took more than two types of pain medication, and this decreased to 36 (33.0%) after the educational pain management program was completed. The mean pain scale score and the number of pain medications decreased, compared to the baseline values. Compared to the non-response group, the response group had a shorter duration of pain onset (p=0.004), and a higher initial number of different medications (p<0.001) and certain types of medications. CONCLUSION: This study results imply that an educational pain management program, can be a valuable complement to the treatment of spinal cord injured patients with neuropathic pain. Early intervention is important, to prevent patients from developing chronic SCI-related pain.ope

분변 중 미량원소측정을 통한 어린이의 토양섭취량 추정

Thesis(masters) --서울대학교 보건대학원 :환경보건학과(환경보건전공),2010.2.Maste