외팔보 진동의 시간 최적제어

박영필,정승호 연세대학교 산업기술연구소 1986 논문집 Vol.18 No.1

The feedback controller for the active control of a cantilever beam vibration is developed using time optimal bang-bang control theory. The effects of I)the constraint of the control force magnitude and II)the actuator positions are investigated numerically. The results show that I)the magnitude of the constraint force and control time are inversely proportional, II)the control effect is increased as the actuator position moves toward the free end of the beam, and III)the controller gives Coulomb damping effect to the system.

한국인에게 적절한 기관삽관 위치

이승한,최옥경,정구영,정성필 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

Endotracheal intubation is one of the important procedures in ED and various fields. Endobronchial intubation can lead to hypoxemia secondary to tension pneumothorax of intubated side and atelectasis of contralateral side. The placement of tube beyond the vocal cords may results in inadvertent extubation, larygeal spasm and aspiration pneumonia. The conformation methods of endotracheal intubation are auscultation of the chest, observation of a vapor trail, oximetry and capnography, and radiologic evaluation. Owen and associates recommended that oral intubation tubes at the upper incisor teeth at the 23cm in men and the 21cm in women of average adult size would have led to proper placement. We studied that whether the proper depth of endotracheal tube in American is appropriate to Korean. We studied adult patients admitted to ED (of both hospitals during March in 1995. Endotracheal tubes in men were positioned at the 23cm and women had positioned at the 21cm at the upper incisor teeth. The distance of the tip of the endotracheal tube to the tracheal carina on the postintubation chest X-ray then determined. Correct placement of intubation was defined with the tip of the tube≥3cm above the carina and below the level of the larynx. Fifty adult patients were enrolled in the study ; 29 men (58%) and 31 women (42%). Mean height and weight were 170±5.2cm, 68±9kg in men and 158±6.5cm, 56±10kg in women. Reasons for intubation were ; respiratory failure(38%), trauma(16%), increased intracramial pressare(16%), drug intoxication(12%), shock(8%), cardiac arrest(7%)and others(3%). The mean distance from the tip to carina on chest X-ray was 4.13±1.5cm in men and 3.45±2.1cm in women. Proper position was 27/29(93%) in men, 14/21(67%) in women or 41/50(82%). this means the placement of endotracheal tube of our patients was positioned deeper than prion study group(97.6%).(p<.05) We recommend that the 22cm tube mark for men and 20cm tube mard for women at upper incisor teeth would have led to proper placement in Korean adult patient.

회전하는 유연한 조작기의 진동 해석

김승호,하영균,정승호,박영필,황효성 연세대학교 산업기술연구소 1985 논문집 Vol.17 No.2

An analytical and experimental investigation is made to the dynamic response of a cantilever with a tip mass that models some of the basic phenomena involved in the response of a flexible manipulator with a tip mass on its free end under the given rotating motion. The system equation is derived from the Hamilton's principle on the basis of the Euler-Bernoulli hypothesis and an approximate solution is obtained from modal analysis using Galerkin's method for the vibration response of the system subjected to a sudden stop after an impulsive rotation. Experiment was performed to verify the validity of the theoretical analysis. Results are given for the vibration amplitude of the free end with respect to tip mass ratio, non-dimensionalized rotating velocity, rotating angle and non-dimensionalized hub length. The rotating condition to minimize the vibration amplitude of the free end can be determined for the given basic parameters.

정신병적 증상이 동반된 기면병 1예

홍승철,송정민,정종현,권용실,한진희,이성필 大韓神經精神醫學會 2003 신경정신의학 Vol.42 No.5

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, cataplexy, sleep paralysis, hypnagogic hallucinations and disrupted nocturnal sleep. We report a patient with a diagnosis of schizophrenia who was subsequently diagnosed as narcolepsy. A case of a 22-year-old woman with concomitant narcolepsy and psychotic symptoms was discussed from a perspective of the diagnosis and therapeutic challenges, particularly on pharmcological treatment dealing with issues raised by their coexistence.

벌자상 후에 발생한 급성심근경색증 2례

민영기,정윤석,박인철,조준필,탁승제 대한응급의학회 2000 대한응급의학회지 Vol.11 No.3

Acute myocardial infarction after a bee sting is a very rare process. Among proposed mechanisms, vasospasm of the coronary artery ㅑs the most probable mechanism. Many mediators are included in the venom of wasps, and those mediators have vasoconstrictive properties and may constrict the coronary artery. Furthemore, those mediators have thrombogenic properties that lead to thrombogenesis in the coronary artery and aggravate myocardial ischemia. Epinephrine, commonly used in the management of anaphylactic shock, may further aggravate myocardial ischemia, We experienced two cases of acute myocardial infarction after a bee sting. In the first case, we could find no underlying abnormalities of the coronary vessel because the patient died during coronary angiography. In the second case, the electrocardiogram showed inferior wall myocardial infarction, but only mild stenosis of the right coronary artery was seen in coronary angiography.

축류 압축기의 선회실속시 날개의 진동특성

지태한,정승호,박영필 연세대학교 산업기술연구소 1989 논문집 Vol.21 No.1

In this study,the effects of the rotating of the rotating stall on the blade vibration of axial compressor is studied. The blade is assumed to be as a cantilever and periodic pressure fluctuation due to rotating stall is assume to be consisted of couple of small pulses. The effect of the period of rotating stall and pulse width on the vibration characteristics of blade are obtained. Identification algorithm of the applied external force due to rotating stall is developed.

최근 5년간 요로감염의 원인균 및 항생제 감수성

김세웅,임필빈,정웅교,이승주,이지열,조용현,윤문수 대한화학요법학회 2002 대한화학요법학회지 Vol.20 No.3

배경 : 최근 요로감염 원인균에 대한 내성 증가로 항생제 감수성에 변화를 가져와 요로감염 환자에게 경험적 1차 치료를 위한 항생제 선택에 어려움을 주고 있다. 단순 및 복잡성 요로감염으로 진단 받은 환자들을 대상으로 원인균과 그에 따른 항생제의 감수성을 살펴봄으로써 향후 단순 및 복잡성 요로감염에 대한 항생제의 선택에 도움을 받고자 한다. 대상 및 방법 : 1996년 6월부터 2001년 5월까지 요배양 검사상 요로 감염균이 10^5cfu/ml 이상의 집락이 형성된 200명을 대상으로 해부학적 또는 구조적인 장애 유무에 따라 단순 요로감염 및 복잡성 요로 감염으로 나누어 각각의 원인균과 그에 따른 항생제의 감수성을 후향적으로 분석하였다. 결과 : 복잡성 요로감염의 가장 흔한 원인질환은 신경인성 방광이었다. 단순 요로감염의 가장 흔한 원인균은 E. coli (61.35%)였고 복잡성 요로감염에서는 E. coli 이외의 균이 E. coli 보다 더 흔한 원인균이었다(58.9%). 단순 및 복잡성 오료감염 중 그람 양성균에서는 vancomycin, penicillin 이 높은 감수성을 보인 반면 ciprofloxacin, imipenem이 낮은 감수성을 보였고 그람음성균에서는 amikacin, imipenem이 높은 감수성을 보인 반면 ampicillin, bactrim이 낮은 감수성을 보였다. 결론 : 단순 및 복잡성 요로 감염의 주 원인균으로 그람 음성균주 특히, Ecoli에 의한 감염이 많은 비중을 차지하고 있으나 빈도가 점차적으로 감소하는 추세이다. 또한 병원성 감염 및 도뇨관의 장기 유치에 따른 교대균의 증가, 비병원성 세균의 출현 등으로 인한 E. coli 이외의 기타 그람음성균 및 그람양성균의 증가하는 추세이다. 향후 임상에서 요로감염의 일치 치료제로 많이 사용되고 있는 ampicillin과 bactrim 등의 항생제의 감수성이 낮으므로 사용시 필요하다고 사료된다. Backround : The increasing frequency of failure of urinary tract infections (UTIs) may be due to emerging resistance to commonly prescribed antimicrobials. We studied the causative microorganisms and their antibiotic sensitivities in uncomplicated and complicated UTIs. Methods : We analyzed 219 microorganisms and their antibiotic sensitivities of 200 outpatients who had more than 10^5cfu/ml on urine from June 1996 to May 2001 retrospectively. The patients weredivided into 2 groups, uncomplicated UTI group and commplicated UTI group according to with or without underlying disease. Results : The most common underlying disease of complicated UTI was neurogenic bladder. The most common pathogenic microorganism was Escherichia coli (E. coli) (61.35%) in uncomplicated UTI group but in complicated UTI, non-E, coli(58.9%) was more common than E. coli. In uncomplicated and complicated UTI, vancomycin, penicillin showed relatively higher sensitivity of gram positive organisms, while ciprofloxacin, imipenem showed relatively lower sensitivity, and imipenem, amikacin showed relatively higher sensitivity of gram negative organisms, while bactrim, amipicillin showed relatively lower sensitivity. Conclusion : We consider that gram negative microorgansisms, especially E. coli, is the main cause of UTI. But, we should concern about the increase of gram positive organsms and other gram negative organisms besides E. coli. Bactrim, amipicllin which were prescribed empirically in UTIs, showed relatively lower sensitivity. Regarding tom the choice of adequate drug in the treatment of UTI, it is necessary to consider the change of pathologic microorganisms.

터키 지진 현장에서의 의료지원에 대한 분석

김재우,박승현,정윤석,조준필 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: The earthquake, measuring 7.4 on the Richter scale, on the 7th of August 1999 in Turkey left forty thousand injured or dead and caused billions of dollars in damages. Our medical team treated 3362 patients with a total number of 3703 visits in the area of Yaloba city for 12 days from the 26th of August to the 7th of September. Method: We retrospectivery analyzed the patients' charts after the medical service. Results: we found that there were no gender differences in the patients. The average age was 35.6 years, with patients in their 30s and 40s making up 42% of the total patients. The average number of visits per day was 300, and major complaints such as headache was most common, accounting for 13.7% of the cases. Cough and sputum were the second most common, acconuting for 12.2%. back pains, skin diseases, and abdominal pains appeared frequently. Conclusion: Disaster-related injuries and illnesses vary according to the type of disater and the time from the onset. Therefore, appropriate planning and medical support are required and should be improved based on experience. Korean disaster plans should also be improved.

레이저 스페클간섭법에 있어서 스페클크기와 측정 한계에 관한 연구

윤성운,김경석,양승필,정현철,김정호,이도윤 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.1

The high coherence of laser beam has made it possible to observe interference effects even in the light scattered from rough surfaces. That's why, when object with a scattering surface is illuminated with laser light, we do see a speckled appearance due to random interference. This sort of unique property of laser speckle has brought into existence the new noncontacting techniques such as speckle metrology method of measuring deformation, displacement, and vibration etc of objects with high optical sensitivity. The measurable range of speckle metrology especially used to measure in-plane information, however, is limited by some factors, the so-called strain, rotation, tilt of surface and out of displacement perpendicular to the plane of analysis. This restrictions severly limits the measurable range of speckle metrology by causing the decorrelation of speckle patterns. It is the purpose of this paper to give a survey on the measurable limitation of speckle photography method that is one of speckle metrology. Namely we will discuss the mutual relationships and problems of each limitations adding the restriction of the largest and smallest displacement measurable with speckle methods.

정상 체중인 성인 남성에서 지방과다와 심혈관질환의 위험요인간의 관련성

권우성,김준수,채진욱,이근미,정승필,문용 영남대학교 의과대학 2003 Yeungnam University Journal of Medicine Vol.20 No.1

정상체중을 가진 성인 남성에서 지방과다(adiposity)와 심혈관계 질환의 위험요인과의 관련성을 알아보고자 하였다. 2001년 1월 3일부터 12월 31일까지 영남대 학교의료원에서 종합검진을 받은 만 28∼69세 성인 남성 129명을 대상으로 연령, 신체계측, 혈압, 공복 혈당, 혈청 지질대사치와 체성분 검사를 실시하였다. 체질량지수(BMI)가 18.5∼23 kg/㎡(76명)인 정상체중군과 23∼25 kg/㎡(53명)인 과체중군으로 분류하고, 체비방률, 체지방량과 위험인자들(수축기혈압, 이완기혈압, 공복시 혈당, 중성지방, 저밀도지단백, 고밀도지단백)의 상관관계를 분석하고, 정상체중군을 지방과다에 따라 3군으로 나누고, 각 군과 과체중군에서 심혈과 질환의 위험인자를 평가하였다. 정상체중의 제1군을 기준으로 제2, 3군과 과체중군의 위험인자 존재에 대한 비차비(odds ratio)를 조사하였다. 정상체중군에서 지방과다 변수들(adiposity variables: 체지방량, 체지방률)과 수축기 및 이완기 혈압, 저밀도지단백, 중성지방에서 유의한 상관관계가 있었다. (P<0.01). 나이를 보정하고 난 뒤 제1군을 기준으로 제3군(체지방율: 3.7, 체지방양: 4.7)과 과체중군(체지방율: 6.6, 체지방양 11.5)에서 위험인자에 대해 더 높은 비차비를 가졌다. 지방이 많은 정상체중의 성인남성은 적은 지방을 가진 성인 남성보다 심혈관 질환에서 더 높은 유병 위험도를 가졌다. 지방 측정은 정상체중군에서 심혈관계 질환의 위험인자외에 추가적인 정보를 제공할 수 있었다. Background: Most of all studies about the relation between the health risk and obesity are based on the European and American data. The purpose of this study is to examine the relation between adiposity and factors for cardio vacular disease (CVD) in normal weight individuals. Materials and Methods: Normal weight subjects with a body mass index (BMI) between 18.5 and 23 kg/㎡(76 subjects) and overweight subjects with a BMI between 23 and 25 kg/㎡ (53 subjects) were retained for this study. Normal weight subjects were divided into three group of each adiposity variable, then three group and the overweight group were evaluated for the presence of CVD risk factors and analyze the correlation coefficients between adiposity variables and risk factors controlled for age in normal weight, overweight groups. Using logistic regression analysis, the odds ratio (OR) for the prevalence of risk factors for each group of adiposity variables and the overweight group was estimated relative to the first group in normal weight subjects. Results: Systolic BP, diastolic BP, LDL cholestrol, HDL cholesterol, triglycerides in normal weight subjects were significantly correlated with all adiposity variables (P<0.01). Third group (3.7 for %fat and 4.7 for fat mass) of adiposity variables in the normal weight group and the overweight group (6.6 for %fat and 11.5 for fat mass) tended to have higher ORs compared to first group for risk factor variables. Conclusion: Normal weight subjects with elevated adiposity had higher prevalence of risk factors than normal weights subjects with less adiposity. Measuring of adiposity added additional information of cardiovascular disease risk factors in normal weight subjects.