데스크탑 밀링머신의 고속 스핀들 설계 해석

장성현,황현영,정우영,홍정표,최영휴 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

During a decade, there are many researches on microfactory which is the miniature, flexible, and efficient manufacturing system for the micro/meso scale machining device. Moreover many micro machine tool has developed in Japan, U.S., Europe, and Korea. Already we are developing a desktop milling machine with 380×450×450 ㎣ machine size for microfactory or BT (Bio technology) factory. In this study, we carried out the design analysis of a high speed spindle system for our desktop milling machine by using ADROS, which is our own developed S/W for dynamic design analysis of rotor systems. As the result, we obtained some analyzed dynamic characteristics of a spindle system, such as natural frequency, whirl frequency, critical speed, and harmonic response.

조기발병형 파킨슨병환자와 정상인의 호흡 및 발성 특성 비교

전은애(Eun Ae Chun),손영호(Young Ho Shon),백승재(Seung Jae Baek),이필휴(Phil Hyu Lee),남정모(Chung Mo Nam),이지은(Ji Eun Lee),최예린(Yaelin Choi) 한국언어청각임상학회 2010 Communication Sciences and Disorders Vol.15 No.4

배경 및 목적: 파킨슨병은 호흡과 발성에 영향을 준다. 49세 이전에 발병하는 조기발병형 파킨슨병(young-onset parkinson’s disease: YOPD, 이하 YOPD)도 호흡과 발성에 문제가 있는지 보기 위해 정상군과 비교하여 살펴보고자 하였다. 또한 파킨슨병 환자의 음성에 관한 연구는 있었지만 YOPD 환자의 음성특성에 대한 호흡과 발성 기능에 대해서 연구된 선행연구는 찾아보기 어렵다. 방법: YOPD 환자군 6명과 빈도대응 시킨 정상군 6명을 대상으로 호흡기능 평가를 위하여 MicroQuarkⓇ를 이용하여 노력성 폐활량(forced vital capacity: FVC, 이하 FVC), 1초간 노력성 호기량(forced expiratory volume at one second: FEV1, 이하 FEV1)과 1초간 노력성 호기량의 노력성 폐활량에 대한 비(이하 FEV1/FVC)를, 음향학적인 평가를 위하여 Multi-Dimentional Voice Program(이하 MDVP)를 이용하여 주기간 주파수 변동률 (이하 jitter)과 주기간 진폭 변동률(이하 shimmer)을, 공기역학적인 평가를 위하여 Phonatory Aerodynamic System(이하 PAS)를 이용하여 평균호기류율(mean airflow rate: MFR, 이하 MFR)과 성문하압(subglottal pressure: Psub, 이하 Psub)을, MDVP를 이용하여 최대발성지속시간(maximum phonation time: MPT, 이하 MPT)을 측정하고 분석하였다. 이비인후과 전문의사가 후두 스트로보스코피(stroboscopy)를 통해 후두의 병리 유무를 평가하였다. 두 집단의 호흡기능, 발성기능의 차이는 맨-휘트니 U검정(Mann-Whitney U-test)을 실시했다. 결과: MPT는 YOPD 환자군에 비하여 정상군이 통계적으로 유의하게 길었고, jitter와 shimmer는 정상군에 비하여 YOPD 환자군이 통계적으로 유의하게 컸다. 그러나 두 군간의 FVC, FEV1, FEV1/FVC, MFR, Psub은 통계적으로 유의한 차이가 없었다. 논의 및 결론: 두 집단 간의 호흡기능에서 차이가 없고 YOPD의 MPT, jitter, shimmer가 정상범주를 벗어나 차이가 있다. 이들 변수들이 YOPD의 음성적 진단, 치료계획과 예후를 판단하는데 도움이 될 것이다. 따라서 본 연구는 ‘연령’이라는 혼란변수를 배제하고 파킨슨병의 음성 특성을 규명 하는데 의의가 있다고 할 수 있다. Background & Objectives: Parkinson’s disease affects respiration as well as phonation. Young-onset Parkinson’s disease (YOPD) can occur even before the age of 49 years. The present study selected YOPD patients in such a manner as to exclude the confounding variable of ‘age’ and thus examine the vocal characteristics of Parkinson’s disease solely. We aimed to compare the respiration function and phonation characteristics of these YOPD patients with a normal group. Methods: The present study’s subjects included a YOPD group comprised of 6 patients whose chronological ages were between 38 and 49 years and onset ages were prior to 49 years, and a normal group comprised of 6 subjects selected by frequency-matching. For testing respiration function, FVC, FEV1 and FEV1/FVC were measured using Cosmed’s MicroQuarkⓇ as a basic test for the ventilation function of the lung. For vocal sampling, the Multi-Dimensional Voice Program (MDVP) and the Advanced Model 5105 of KayPENTAX’s Computerized Speech Lab (CSL) Model 4400 were used to analyze maximum phonation time (MPT), jitter, and shimmer. Additionally, KayPENTAX’s Phonatory Aerodynamic System (PAS) 4500 was utilized to analyze mean air flow rate (MFR) and subglottal pressure (Psub). Otolaryngologists and neurologists participated in the research cooperatively, and the otolaryngologists assessed the presence of laryngeal disease directly through larynx stroboscopy in the all subject. Mann-Whitney’s U test was used to analyze the difference between the 2 groups’ respiration and phonation function. Results: The MPT was longer in the normal group than YOPD patient group, and both jitter and shimmer were larger in the YOPD patient group than the normal group; both of these differences were statistically significant. However, there was no statistically significant difference in FVC, FEV1, FEV1/FVC, MFR, and Psub. Discussion & Conclusion: The 2 groups’ respiration function did not differ, and YOPD patients’ MPT, jitter, and shimmer differed beyond the normal range. Thus, these variables will help in YOPD patients’ phonation diagnosis and therapeutic plans or prognosis. Although there have been studies on the phonation of Parkinson’s disease patients, limited advanced research can be found on the respiration and phonation function of YOPD patients’ vocal characteristics. The results of this study are meaningful and provide a better understanding of Parkinson’s disease because the subjects were selected such that confounding by age was avoided.

6LoWPAN을 위한 단편 패킷의 저전력 멀티홉 전송 기법

김일휴,남영진,김 창 훈 대구대학교 정보통신연구소 2010 情報通信硏究 Vol.7 No.1

The fragmentation and reassembly of IP data packet is one of the most important function in the 6LoWPAN based communication between Internet and wireless sensor network. However, since the 6LoWPAN determines the destination node with 16-bits or 64-bits address, it increases the number of fragmentation and reassembly. In order to reduce the number of fragmentation and reassembly, this paper presents a new scheme that can be applicable to 6LoWPAN. When a fragmented packet header is constructed, we can have more space for data. This is because we use 8-bits routing table ID instead of 16-bits or 64-bits MAC address to decide the destination node. Analysis shows that our design has roughly 7% or 22% less transmission number of fragmented packets, depending on MAC address size(16-bits or 64-bits), compared with the previously proposed scheme in RFC4944. The reduced fragmented packet transmission means a low power consumption since the packet transmission is the very high power function in wireless sensor networks. Therefore the presented fragmented transmission scheme is well suited for low-power wireless sensor networks. 6LoWPAN 프로토콜의 주요 기능 중 단편과 재조합의 기능은 무선 센서네트워크와 인터넷간의 데이터 전송을 가능하게 하는 가장 중요한 기능이다. 그러나 6LoWPAN에서는 IP 패킷의 단편화시 16-비트 혹은 64-비트의 주소로서 목적지를 판단하기 때문에 데이터 패킷을 위한 공간이 부족하여 단편 및 재조합의 횟수를 증가 시킨다. 본 논문에서는 6LoWPAN상에서 데이터의 단편 횟수를 줄일 수 있는 새로운 기법을 제안한다. 제안된 기법은 단편 패킷 헤더 구성 시 주소가 아닌 8-비트 라우팅 테이블 Id를 사용함으로써 데이터 저장을 위한 더 많은 공간을 확보 할 수 있다. UTRC-SN110 센서 노드를 이용한 실험 결과 기존 RFC4944에서 제안된 단편 패킷 전송 방식과 비교 분석한 결과 16-비트 주소방식보다 약 7%, 64-비트 주소방식보다 약 22%의 전송 횟수 감소를 보인다. 무선 센서노드에서 패킷의 전송은 많은 전력을 소모하기 때문에 패킷 전송횟수의 감소는 전력 소모량의 감소를 의미한다. 따라서 본 논문에서 제안한 단편 패킷 전송기법은 에너지 사용량이 중요한 무선 센서네트워크 응용에 적합하다 할 수 있다.

시판 참기름 및 참깨제품의 진위판별에 있어서의 지방산 및 Sesamol 성분의 이용

최효선,고영수 漢陽大學校 韓國生活科學硏究所 1995 韓國 生活 科學 硏究 Vol.- No.13

An attempt was made to use the fatty acid and sesamol composition as a basis for the identification of sesame oil and sesame products adulteration. In 23 kinds sesame oil and 7 kinds of sesame and sesame products pressed experimentally, the ratio of oleic to linoleic acid content (O/L ratio) were in the variable ranges of 0.71-0.98. Only 14 among 30 collected sesame oils and sesame products were found to be pure sesame oil by fatly acid and sesamol content value determination. In 16 adulterated sesame oils, it was revealed 5 samples were adulted soybean oil, 4 with rice bran oil, 4 with corn and perilla seed oil and 3 with rape seed oil.

3차원 DOUBLE-TRACK 차량모델을 이용한 자동차의 주행거동해석

최영휴 國立 昌原大學校 産業技術硏究所 1994 産技硏論文集 Vol.8 No.-

The conventional 2-dimensional single track vehicle model has degrees of freedom related to only planar motions, and neglects the effects of suspension systems on vehicle manoeuvres. Whereas a 3-dimensional 12-degree-of-freedom vehicle model was proposed, in this study, to analyze handing and riding behaviors with taking into account the effects of nonlinear suspension and steering systems. The computed results of the proposed model are in good agreement with test results compared to the 2-dimensional model. Especially the proposed model showed the better accuracy near the characteristic speed and in high lateral accelerated manoeuvres.

평면운동모델을 이용한 LMG 상에서 이송되는 Cross Head의 사행동 해석

최영휴,김성훈,정택수 國立 昌原大學校 産業技術硏究所 2002 産技硏論文集 Vol.16 No.-

In this paper, a simple 2 D.O.F. planar motion model is proposed in order to analyze the snake motion of a cross head assembly travelling on linear huide rails. In the proposed mathematical model, the head assembly and a ball screw are assumed to be rigid, but the rear-panel of the machining center is assumed to be flexible. The equations of motion of the proposed model are derived and solved by Runge-Kutta method to determine vibration responses of the head assembly due to some applied traction forces.

Electromyography 기법을 이용한 씨름 덧걸이 기술의 상체 근 동원 비교분석

신성휴,임영태,김태완,박기자,권문석 한국운동역학회 2003 한국운동역학회지 Vol.13 No.1

Shin, S-H · Lim, Y-T · Kim, T-H · Park, K-J and Kwon, M-S. Electromyographical Analysis of Muscle Activities of Upper Trunk for Ssireum Dutguri Technique. Korean Journal of Sport Biomechanics, Vol. 13, no. 1, pp. 95-108. The purposes of this study were to analyze the muscle activities and the characteristics of muscle recruiting patterns of upper trunk for Ssirum dutguri technique using three top-ranked elite Ssirum players. The EMG technique was used to record muscle activities of both right and left sides of latissimus dorsi, biceps brachii, and erector spinae. Six surface electrodes were placed on the surface of the selected muscles and one ground electrode was also attached on the back of neck(C7). One video camera was also used to record the Ssirum motion to define 4 events and 3 phases for further analysis. The raw EMG data were filtered with band pass filter (50-400 Hz) to remove artifacts and then low pass filtered (4 Hz) to find the linear envelope which resemble muscle tension curve. This filtered EMG data were normalized to MVIC for the purpose of comparion between the subjects. The results were indicated that each subject with different physical characteristics showed very different muscle activity patterns. Although Ssirum dutguri is considered as foot technique the player grasped opponent's satba(belt) with both hands when they play. Because of this reason, activities of upper trunk muscles were relatively high. However, direct comparison between upper and lower body muscles was not possible due to the lack of the data in present study. Interestingly, all threes subjects showed that erector spinae muscle activity was comparatively higher than those of latissimus dorsi and biceps brachii. This implies to reinforce back muscle as a routine of training to improve performance or to prevent back injury. implies to reinforce back muscle as a routine of training to improve performance or to prevent back injury.

유연도 영향계수법을 이용한 결합부 구조물의 등가강성 모델링

최영휴,신중호,박종권 國立 昌原大學校 産業技術硏究所 1995 産技硏論文集 Vol.9 No.-

A practical method is proposed to construct a slide-way joint structure as an equivalent stiffness matrix element in the methematical modeling of structural dynamic characteristics. At first, the detail finite element model of a slide-way joint structure was buildup. From the finite element model, the equivalent stiffness matrix element was constructed by using the influence coefficient method and Guyan condensation concept. The proposed method was applied to finite element modeling and analysis of a double column gate type grinding machine structure. And the analysis results were compared with those from the equivalent spring element modelling method by Yoshimura??. Both results are in good agreement.

차륜주행충격에 의한 빗살형 교량 신축이음장치 구조물의 과도진동해석

최영휴,김현욱,김광영 國立 昌原大學校 産業技術硏究所 1998 産技硏論文集 Vol.12 No.-

In this paper we derive relations which describe the geometry and kinematics of contact between the travelling wheel and stepped comb joint. From which we can obtain the impulse, impulsive force and its time interval due to travelling wheel impact which can not be taken from Carter's model or Newland and Cassidy's. The calculated transient responses of the comb joint structure to travelling wheel impact reveals that the proposed wheel contact model and Carter's give very similar results but Newland Cassidy's model make a quite different results from the others.

비대칭 안모의 치험 2례

현용휴,설인택,김영균,여환호,이철우 大韓顎顔面成形再建外科學會 1992 Maxillofacial Plastic Reconstructive Surgery Vol.14 No.4

Facial asymmetry can be most distressing for the young child and parents. It can cause functional problems as a result of malocclusion. Classification of facial asymmetry has not been yet well-organized because of its varieties on etiologic factors, involved sites and clinical expressions. Even though, we don’t know its causes definitely. It is generally believed that problems with aberrant pattern of condylar growth are related to facial asymmetry. This is a case report on surgical correction of the patients who had severe facial asymmetry. One patient was diagnosed as condylar hyperplasia and the other was diagnosed as a condylar hypoplasia related to trauma. We performed a simultaneous two-jaw surgery, condylar shaving, inferior border ostectomy of affected mandible in the former case, and a simultaneous two-jaw surgery, reverse-L osteotomy and alloplastic implantation with Biocoral in the latter case. The postoperative results of the two cases were excellent functionally and esthetically.