균일분포 온도하의 두꺼운 복합 재료 적층판의 열적 좌굴 해석

이영신,이열화,양명석,박복선,이종수,Lee, Young-Shin,Lee, Yeol-Wha,Yang, Myung-Seog,Park, Bock-Sun,Lee, Jong-Soo 대한기계학회 1993 대한기계학회논문집 Vol.17 No.7

In this paper, the thermal buckling of thick composite angle-ply laminates subject to uniform temperature distribution is studied. For the plates of 4-edges simply supported condition and those of 4-edges clamped condition, the critical buckling temperatue is derived, using tile finite element method based on the shear deformation theory. The effects of lamination angle, layer number, laminate thickness, plate aspect ratio and boundary constraints upon the critical buckling temperature are presented.

퍼지 제어를 적용한 교차로에서의 최적 교통 신호 시스템

이영신,이윤배,Lee, Yeong-Sin,Lee, Yun-Bae 한국정보처리학회 1997 정보처리학회논문지 Vol.5 No.1

교차로에서 통행 패턴의 계속적인 변화와 교통량의 증가 때문에, 매시간 변화에 따라 교차로를 유연성있게 관리할 수 있는 효율적인 교통제어 시스템이 필요하다. 본 논문에서는 교차로를 구성하는 각 도로로 복합성을 자율적으로 분석하여 그 결과에 따라 교차로를 통과할 수 있는 시간을 결정하는 제어 시스템에 관해 연구하였다. 교 통신호 제어를 위해 퍼지 논리 제어기에 퍼지 개념을 적용하였으며, 퍼지 논리 제어 기의 최적 수행을 증명하기 위해서 규칙 신호 시스템을 비교하고 시뮬레이션을 통해 타당성을 증명하였다. 시뮬레이션 결과 교통 제어의 효율성이 6% 정도 향상되었다. Due to continuous change in traffic and increase in traffic volumes at the intersection, efficient traffic control system is required to manage road situations flexibly in accordance with the change occurring every hour. In this paper, we study the control systems which will help us to determine the interva ls of intersection following the autonomous analysis of complexity of the road. Fuzzy logic control concept was applied to the fuzzy logic controller(FLC) for controlling traffic signal. Furthermore the fuzzy signal systems were compare with the regular signal systems to prove higher performance of the FLC presente d in the paper. By means of simulation, the validity of FLC was proven. About 6% increase in the efficiency of traffic control based on the proposed algorithm in this paper was when we use the simulation.

IP 기반 망에서 H.323 리라우팅을 이용한 핸드오프 시그널링 구현

이영신,최기무,Lee, Yeong-Sin,Choi, Gi-Moo 한국정보처리학회 2001 정보처리학회논문지 C : 정보통신,정보보안 Vol.8 No.6

H.323은 이동 단말에 핸드오프(Handoff)를 지원하기 위해 Mobile IP와 H.323 다자간 회의(Multi-point conference) 시그널링을 사용할 것을 제안하고 있다. 하지만 다자간 회의 시그널링은 단말이 복잡한 시그널링을 수행해야 하고 이에 따른 핸드오프 시간이 길어진다는 단점이 있다. 본 논문에서는 H.323 리라우팅(Third party initiated Pause and Rerouting)이 이용된 핸드오프 시그널링을 제안한다. H.323 리라우팅 시그널링은 H.323 단말(Endpoint)이 기본적인 스택만으로 미디어 채널을 재설정하기 때문에 H.323 제품 간의 연동(Inter-Operability)을 쉽게 할 뿐 아니라 빠른 핸드오프를 제공한다. H.323 GK는 H.323 리라우팅 시그널링을 이용하기 위해 패스트커넥트(Fast Connect) 호를 포함한 모든 호에 대해서 터널링을 사용하여 H.245 제어 채널을 유도한다. 제안된 핸드오프 시그널링을 평가하기 위해 H.323 리라우팅이 이용된 호전환(Call Transfer)과 다자간 회의 시그널링을 연동과 시그널링 시간 측면에서 비교하였다. 성능을 평가한 결과 리라우팅이 사용된 호전환은 5개의 제품 중 4개의 제품과 연동이 되었으며 시그널링 시간은 평균 1.4초 빨랐다. H.323 proposes to use Mobile IP and H.323 ad hoc conference signaling to provide Handoff function to a mobile terminal. But H.323 ad hoc conference signaling has a drawback. It requires an H.323 endpoint to do a complex conference signaling which makes inter-operability between H.323 endpoints difficult and takes the longer signaling time. In this paper, we propose an Handoff signaling using H.323 rerouting(Third party initiated Pause and Rerouting). H.323 rerouting signaling only requires an H.323 endpoint to do H.323 basic signaling in reestablishing media channel, and makes inter-operability more easier and provides the faster Handoff. To do this, our H.323 GK has derived H.245 control channel using tunneling for all H.323 calls including the fast connect calls which enable endpoints communicate each other if they don\`t have H.245 control channel. In order to evaluate the performance of the proposed signaling, we have conducted an experiment that compares a call transfer signaling using H.323 rerouting with ad hoc conference signaling in inter-operability and signaling delay. The results of our experiment shows that the call transfer signaling can inter-operate with four H.323 endpoints among five H.323 endpoints of other vendors and reduces the signaling delay average 1.4 sec.

등급 양방향 진화적 구조 최적화에 관한 연구

이영신,류충현,명창문,Lee, Yeong-Sin,Ryu, Chung-Hyeon,Myeong, Chang-Mun 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.9

The evolutionary structural optimization(ESO) method has been under continuous development since 1992. The bidirectional evolutionary structural optimization(BESO) method is made of additive and removal procedure. The BESO method is very useful to search the global optimum and to reduce the computational time. This paper presents the ranked bidirectional evolutionary structural optimization(R-BESO) method which adds elements based on a rank, and the performance indicator which can estimate a fully stressed model. The R-BESO method can obtain the optimum design using less iteration number than iteration number of the BESO.

고차 전단 변형이론에 의한 복합재료 적층판의 저속 충격응답

이영신,박웅,Lee, Young-Shin,Park, Oung 대한기계학회 1990 대한기계학회논문집 Vol.14 No.6

본 연구에서는 Kant 등이 제안한 고차판이론의 C연속변위 유한요소 모델을 사 용하여 충격자와 적층판의 저속 충격 응답에 대하여 연구하여 그 결과를 Mindlin의 판 이론에 의한 계산 결과와 비교하고, 경계 조건의 영향 및 충격자의 충격속도, 질량변 화에 대한 접촉력의 변화를 고찰하고자 한다. A $C^{0}$ continuous displacement finite element method based on a higher-order shear deformation theory is employed in the prediction of the transient response of laminated composite plates subjected to low-velocity impact. A modified contact law was applied to calculate the contact force during impact. The discrete element chosen is a nine-noded quadrilateral with 5 degree-of-freedom per node. The Wilson-.theta. time integration algorithm is used for solving the time dependent equations of the impactor and the central difference method was adopted to perform time integration of the plate. Numerical results, including the contact force history, deflection, and velocity history, are presented. Comparisons of numerical results using a higher order theory and a first-order theory show that using a higher order theory provides more accurate results. Effects of boundary condition, impact velocity, and mass of the impactors are also discussed.d.

편마비 환자용 플라스틱 단하지보조기의 설계기술개발 (I) - 응력 해석을 통한 접근 -

이영신,최경주,조강희,임현균,Lee, Yeong-Sin,Choe, Gyeong-Ju,Jo, Gang-Hui,Im, Hyeon-Gyun 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.1

In this study, a stress analysis is made fur an ankle foot orthosis (AFO) in the view point of structural stability. The investigated AFO is a solid and standard type. To analyze the stress distribution on the neck of AFO, the maximum AFO angular translation data is obtained by gait analysis. The material test of polypropylene is made to obtain the mechanical properties of AFO. The maximum dorsiflexion appears at the midstance in the gait analysis. The experimental angular translation at the top of AFO is about 10.3$^{\circ}$ at mid stance. Three models of AFO with different width of neck are made and analyzed with ABAQUS 6.1. The stress levels and distributions of 3 different width(W$_1$, W$_2$=0.85W$_1$, W$_3$=0.60W$_1$) AFO are investigated. As a result, the standard type(W$_1$) appears to the maximum stresses at the medial edge of cutout area surrounding ankle joint. The maximum stresses of the narrower type(W$_2$) are occured on medial edge and center of ankle. The narrowest type(W$_3$) appears to the maximum stresses at center of ankle. The maximum stresses become smaller as ankle width of AFO is narrower.

격벽에 의한 조분리와 내부반송을 이용한 산화구 시설의 고도처리개선에 관한 연구

이영신,오대민,Lee, Young-Shin,Oh, Dae-Min 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.1

This study was performed to assess the removal efficiency on nitrogen, phosphorus and organic carbon in wastewater by spatial separation and internal recycling in a modified oxidation ditch process (modified OD). The performances of the modified OD were evaluated via laboratory-scale experiments. The process was operated at hydraulic retention times of 6-48 hours and solid retention times of 17-38 days. We found that organic carbon removal efficiency increased after the modified OD operation period. T-N removal efficiency remained stable; average T-N concentration of effluent was 8.02 mg/l after modified OD operation. In contrast, T-P concentration of effluent was over 1 mg/l. Nitrogen and phosphorus removal efficiency of modified OD at HRT 12 hr were 83.1% and 74.1%, respectively. Also, maximum efficiency was found at SRTs from 20 to 30 days. T-N removal efficiency was 83.1% at a C/N ratio from 3.0 to 3.5. However, T-N removal efficiency decreased at C/N ratios over 3.5. Also, T-P removal efficiency increased with HRT at C/P ratios in the same condition. Maximum efficiency was 74.1% at a C/P ratio from 25 to 28. T-N removal efficiency was 79.2% and T-P removal efficiency was 65.3% after M4 mode operation (added to the internal recycle line connected to the anoxic reactor). The modified OD with spatial separation and internal recycling developed in this study is, therefore, believed to be an improvement for solving problems in the nutrient removal technologies.

충격자의 형상 및 재질변화에 따른 펄스형성에 관한 연구

이영신,김동진,강근희,오종수,Lee, Yeong-Sin,Kim, Dong-Jin,Gang, Geun-Hui,O, Jong-Su 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.1

The impact programmer for impact test was designed and the impact analysis was conducted. The effects of the material and geometric parameters on the impact force and pulse shape were investigated. The impact characteristics were examined by experimental and finite element method. The impact test was conducted with free drop impact tester. The ABAQUS/Explicit 5.5 version was used for finite element analysis. The geometric parameters of the conical and dome type impact programmer were analyzed. The polyurethane impact programmers were fabricated and tested. The effects of the hardness and thickness of the impact programmer were studied. The peak acceleration and time duration of impact programmer have close correlation with the hardness, impact energy and thickness of the impactor. The experiment was good agreement with analytical predictions. The impact pulse shape generated with polyurethane impact programmer was half sine shape. The maximum impact force was proportional to impact energy. The impact acceleration was decreased with thickness of impact programmer. The maximum impact time duration level was about 2 msec.

길이방향으로 보강된 복합재료 원통쉘의 자유진동

이영신,김영완,Lee, Young-Shin,Kim, Young-Wann 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.7

The analytical solutions for the free vibration of cross-ply laminated composite cyllindrical shell with axial stiffeners(stringers) are presented usint the energy method. The stiffeners are taken to be smeared over the surface of shell with the smeared stffener theory. The effect of the parameters such as the stacking sequences, the shell thichness, the shell radius-to stringer depth ratio, the stringer depth-to width ratio, the shell length-to radius ratio are studied. By comparison with the previously published experimental results and the analytical results for the stiffened isotropic cylindrical shell and the unstiffened orthotropic composite laminated cylindrical shell, it is shown that natural frequencies can be determined with adequate accuracy.

한국형 마네킨 구현에 의한 최적 시팅 패키지 설계 치수 제안

이영신,박세진,남윤의,송근영,Lee, Yeong-Sin,Park, Se-Jin,Nam, Yun-Ui,Song, Geun-Yeong 대한인간공학회 1999 大韓人間工學會誌 Vol.18 No.2

The primary objective of this research was to suggest the design dimensions of automotive seating package that has an important effect upon seating package design. To conduct the research, a set of manikin dimensions that are representative for Korean was determined by using a statistical scheme. With these dimensions, we generated nine manikins for male and female, respectively. Also, the preferred driving posture was investigated using the experimental setup. To find each joint angle for subjects, a driving monitoring system was developed and a three dimensional motion analysis system was employed. The joint angle for the subject was established and compared with related literature. With the generated manikins and each joint angle, the driving posture was simulated by using SAFEWORK that is a program to generate manikins. The positions and adjustable ranges from the accelerator heel point to the hip point and the steering wheel center point that are important variables in order to design seating package were suggested. Further research is needed to determine the seating package dimensions three dimensionally.