Multi-agent based traffic simulation and integrated control of freeway corridors: Part 2 integrated control optimization

This research aims to optimize the traffic signal cycle and the green light time per traffic signal cycle at ramps and intersections in arterials to maximize the passing traffic volume and minimize the delaying traffic volume in freeway corridors. For this purpose, we developed the MATDYMO (multi-agent for traffic simulation with vehicle dynamics model) and validated it with comparison to commercial software, TRANSYT-7F, for an interrupted flow model and to URFSIM (urban freeway traffic simulation model) for an uninterrupted flow model. These comparisons showed that MATDYMO is able to estimate the traffic situation with only incoming traffic volume. Using MATDYMO, ramp metering and traffic signal control can be optimized simultaneously. We extracted 80 sampling points from the DOE (Design of Experiment) and derived each response from MATDYMO. Then, a neural network was adopted to approximate the objective function, and simulated annealing was used as an optimization method. There are three cases of the objective function: maximization of the freeway traffic volume, minimization of the delay of ramps and arterials, and the satisfaction of both cases. The optimization results showed that traffic flow in freeway corridors can be maintained to a steady stream by ramp metering and signal control. This paper was recommended for publication in revised form by Associate Editor Kyongsu Yi Myung-Won Suh is a professor of Mechanical Engineering. During 1986–1988, he worked in Ford motor company as researcher. During 1989–1995, he worked in technical center of KIA motors. He took a BS Degree in Mechanical Engineering from Seoul National University and an MS Degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at University of Michigan, USA, in 1989. His research areas include the structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He accomplished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machinery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

A study on reliability centered maintenance planning of a standard electric motor unit subsystem using computational techniques

The design and manufacture of urban transportation applications has been necessarily complicated in order to improve its safety. Urban transportation systems have complex structures that consist of various electric, electronic, and mechanical components, and the maintenance costs generally take up approximately 60% of the total operational costs. Therefore, it is essential to establish a maintenance plan that takes into account both safety and cost. In considering safety and cost limitations, this research introduces an advanced reliability centered maintenance (RCM) planning method using computational techniques, and applies the method to a standard electric motor unit (EMU) subsystem. First, this research devises a maintenance cost function that can reflect the current operating conditions, and maintenance characteristics, of components by generating essential cost factors. Second, a reliability growth analysis (RGA) is performed, using the Army Material Systems Analysis Activity (AMSAA) model, to estimate reliability indexes such as failure rate, and mean time between failures (MTBF), of a standard EMU subsystem, and each individual component Third, two optimization processes are performed to ascertain the optimal maintenance reliability of each component in the standard EMU subsystem. Finally, this research presents the maintenance time of each component based on the optimal maintenance reliability provided by optimization processesand reliability indexes provided by the RGA method. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Myung-Won Suh is a professor of Mechanical Engineering. During 1986–1988, he worked for Ford motor company as researcher. During 1989–1995, he worked in the technical center of KIA motors. He earned a BS degree in Mechanical Engineering from Seoul National University and an MS degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at the University of Michigan, USA, in 1989. His research areas include structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He ac-complished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machinery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

Development of a Web-based RCM system for the driverless Rubber-Tired K-AGT system

The Korean Railroad Research Institute (KRRI) developed the rubber-tired AGT system (Model: K-AGT) between 1999 and 2005. The K-AGT is a light rail transit system does not require a driver and generally operates on an elevated railroad for transporting passengers. Accidents caused by driverless vehicles can severely affect social confidence, safety and economy. Therefore, it is very important to minimize the occurrences of such faults, and to accurately perform detailed maintenance tasks and thoroughly investigate the cause of any repeated failures. This research develops the web-based reliability centered maintenance (RCM) system for the K-AGT train system. The framework of the RCM system is based on performing a failure mode and effects analyses (FMEA) procedure on all the sub-systems in the K-AGT system. Out of the devices that have a low reliability, the high failure ranked devices are included high on the list for performing the overall maintenance plans. Through registration of historical failure data and the reliability indexes, the results of the FMEA can be updated. Such a process is repeated continuously and can achieve very accurate predictions for device operational lifetimes and failure rates. Also, the RCM system is designed so that workers can refer to the expert system for the latest procedures to perform the required diagnosis and repair of any failure. The overall RCM system consists of a failure/task management system, a preventive maintenance system, an expert system, a material management system, and an approval system. This research describes the development of the preventive maintenance system and the expert system that have been produced because these are the main functions for the RCM system. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Myung-Won Suh is a Professor of Mechanical Engineering. During 1986–1988, he worked for Ford motor company as researcher. From 1989–1995, he worked in technical center of KIA motors. He took a BS degree in Mechanical Engineering from Seoul National University and an MS degree in Mechanical Engineering from KAIST, South Korea. He obtained his Doctorate at the University of Michigan, USA, in 1989. His research areas include structure and system optimization, advanced safety vehicle and reliability analysis & optimization. Chul-Ho Bae is a PhD candidate at Sungkyunkwan University in Suwon, South Korea. He accomplished fellowship work as researcher at Mississippi State University, USA, in 2003 and 2005. He worked in Institute of Advanced Machi-nery and Technology (IMAT) as a Research Assistant in 2004. He was a part time Lecturer in computer aided Mechanical Engineering of Ansan College of Technology, Suwon Science College, and Osan College during 2004–2005. He took a BS Degree in Mechanical Design and an MS Degree in Mechanical Engineering from the Sungkyunkwan University. His research interests include computer aided engineering, reliability engineering, and optimization.     

Solid-liquid mixture flow through a slim hole annulus with rotating inner cylinder

An experimental study was conducted to study solid-liquid mixture upward hydraulic transport of solid particles in vertical and inclined annuli with rotating inner cylinder. Lift forces acting on a fluidized particle play a central role in many important applications, such as the removal of drill cuttings in horizontal drill holes, sand transport in fractured reservoirs and sediment transport, etc. Annular fluid velocities varied from 0.4 m/s to 1.2 m/s. Effect of annulus inclination and drill pipe rotation on the carrying capacity of drilling fluid, particle rising velocity, and pressure drop in the slim hole annulus have been measured for fully developed flows of water and of aqueous solutions of sodium carboxymethyl cellulose (CMC) and bentonite, respectively. For higher particle feed concentration, the hydraulic pressure drop of mixture flow increases due to the friction between the wall and solids or among solids. This paper was recommended for publication in revised form by Associate Editor Gihun Son Sang-Mok Han received a B.S. degree in Mechanical Engineering from Sung-kyunkwan University in 2001. He then went on to receive his M.S. degrees from Sungkyunkwan University in 2003. He is a candidate for Ph.D. from 2006 to the present at the School of Mechanical Engineering at Sungkyunkwan University in Suwon, Korea. His research interests are in the area of Multi-phase flow and drilling. Nam-Sub Woo received a B.S. degree in Mechanical Engineering from Sungkyunkwan University in 1997. He then went on to receive his M.S. and Ph.D. degrees from Sunkyunkwan University in 1999 and 2007, respectively. Dr. Woo is currently a Senior Researcher at the Fire & Engineering Services Research Center at Korea Institute of Construction and Technology in Goyang, Korea. Dr. Woo’s research interests are in the area of fluid dynamics and plant engineering. Young-Kyu Hwang received a B.S. degree in Mechanical Engineering from Sungkyunkwan University in 1977. He then went on to receive his M.S. from University of Wis-consin at Madison in 1980 and Ph.D. degrees from State Uni-versity of New York at Buffalo in 1984, respectively. Dr. Hwang has served as a Professor, from 1984 to the present at the School of Mechanical Engineering at Sungkyunkwan University in Suwon, Korea. His research interests are in the area of drilling hydraulics, molecular gas flow and hydrodynamic instability.     

An enhanced real-time dynamic imbalance correction for precision rotors

Even a moderate mass imbalance of a high-precision rotor produces a significant level of vibration when it spins at high revolutionary speed such as 10,000 rpm or faster. As a result, many attempts have been made for the development of dynamic rotor balancing methods mostly by the precision mechanical system industry; however, intensive studies about the fundamental principles from a theoretical point of view should be carried out further. In the present paper, a new dual axes dynamic imbalance correction method is introduced and tested through simulations. The proposed method is more efficient and effective than its predecessors. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Jung Kwan Lee is currently a masteral student in the School of Mechanical Engineering at Sungkyunkwan University Korea. He received his B.S. degree from Sungkyunkwan University. His primary research interests are rotor design, analysis, and rotor dynamics. Hyungpil Moon received his Ph.D. degree in mechanical engineering from the University of Michigan in 2005. He was a postdoctoral fellow at Carnegie Mellon University. He joined the faculty of the School of Mechanical Engineering at Sungkyunkwan University in 2008. Dongho Oh received his Ph.D. degree from KAIST in 1996. He worked as a Principal En-gineer of Samsung Electronics and SAIT. Dr. Oh is currently an Associate Professor at the Department of Mechanical Engineering at Chungnam National University. Ja Choon Koo is an associate professor of the School of Mechanical Engineering at Sungkyunkwan University Korea. He was an engineer at IBM Corporation, San Jose, California. He received his Ph.D from the University of Texas at Austin. His primary research interests are analysis, and control of dynamic systems, mechatronics, sensors, and actuators.     

Measurement of solid propellant burning rates by analysis of ultrasonic full waveforms

The measurement of solid propellant burning rates using ultrasound requires the simultaneous acquisition and analysis of ultrasonic signals and pressure data simultaneously in a wide range of pressure values during the process of propellant burning. Recently, this method has been proposed as an effective approach based on an analysis of full waveforms of ultrasonic signals together with a laboratory prototype system in which the proposed approach has been implemented. However, this prototype system had limitations in terms of data processing speed and signal processing procedures. To overcome such limitations, in the present study, we develop a dedicated, high speed system that can acquire ultrasonic full waveforms and pressure data up to 2,000 times per second. Our system can also estimate the burning rate as a function of pressure using a special software based on ultrasonic full waveform analysis. This paper describes the approach adopted in this high speed system, along with the burning rate measurement results obtained from three propellants with different burning characteristics. This paper was recommended for publication in revised form by Associate Editor Dae-Eun Kim Sung-Jin Song received a B.S. degree in Mechanical Engineering from Seoul National University, Seoul, Korea in 1981, a M.S. degree in Mechanical Engineering from Korea Advanced Institute of Science and Technology in 1983, and a Ph.D in Engineering Mechanics from Iowa State University, Ames, Iowa, USA in 1991. He has worked at Daewoo Heavy Industries, Ltd., Inchoen, Korea for 5 years from 1983, where he has been certified as ASNT Level III in RT, UT, MT and PT. He has worked at Chosun University, Gwangju, Korea as Assistant Professor for 5 years from 1993. Since 1998 he has been at Sungkyunkwan University, Suwon, Korea and is currently Professor of Mechanical Engineering.     

Optimization of the industrial guide-way vehicle to improve the running stability

This paper presents an optimization of the industrial guide-way vehicle that aims to improve running stability at increased speeds. A guide-way vehicle was used to transfer products in various manufacturing industries. Using Design Of Experiment(D.O.E.), the design prototype was optimized. The improved design prototype and its design parameters were obtained by a case study determined by the engineering discussion. The computational model for the optimization was validated by correlation with the test results. Through this procedure, the optimization method presented in this paper has been proven to be effective. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Kab-Jin Jun received a B.S. degree in Mechanical Engineering from Ajou University in 2005. He is currently a Ph.D candidate at Ajou University in Suwon, Korea. His research interests are in the area of optimization, vehicle dynamics. Tae Won Park received a B.S. degree in Mechanical Engineering from Seoul University. He then went on to receive his M.S. and Ph.D. degrees from the University of Iowa. Dr. Park is currently a Professor at the School of Mechanical Engineering at Ajou University in Suwon, Korea. Sung Pil Jung is currently a Ph.D candidate at Ajou University in Suwon, Korea. Mr. Jung’s research interests are in the area of multi-body & structural dynamics, optimization and computer aided engineering.     

Dual stage and an image processing-based method for sight stabilization

This paper presents a combined dual stage-based mechanical and image-based stabilization scheme for a three-axis image-tracking sight system. To improve the stabilization and tracking accuracy, a secondary stage actuated by a pair of electro-magnets is mounted on a conventional elevation gimbal. For the remaining roll axis stabilization, an electronic digital- image stabilization technique is introduced to estimate and correct roll motions. Experimental results are given to demonstrate the effectiveness of the proposed stabilization system and the image-stabilization scheme. This paper was recommended for publication in revised form by Associate Editor Dong Hwan Kim Joon Lyou received a B.S. degree in Electronics Engineering from Seoul National University in 1978. He then went on to receive M.S. and Ph.D. degrees from KAIST in 1980 and 1984, respectively. Dr. Lyou is currently a professor of the Department of Electronics Engineering at Chungnam National University in Daejeon, Korea. His research interests include industrial control and sensor signal processing, IT based robotics, and navigation systems. MinSig Kang received a B.S. degree from the Department of Mechanical Engineering of Seoul National University in 1980. He then went on to receive M.S. and Ph.D. degrees from KAIST in 1983 and 1987, respectively. He worked for the Agency for Defence Development during 1987–1998. Dr. Kang is currently a professor of the Department of Mechanical and Automotive Engineering at Kyungwon University in Sungnam, Korea. His research interests include dynamic systems measurement and control, industrial robotics, and manufacturing systems. HwyKuen Kwak received a B.S. degree in Electronics Engineering from Chungnam National University in 2005. He is currently working on his M.S. and Ph.D. course at Chungnam National University in Daejeon, Korea. His research areas are image signal processing, sensors and digital control systems. YoungJun Choi received a B.S. and M.S. degree in Mechanical Engineering from Kyungwon University in 2004 and 2006. He is currently a researcher for the Agency for Defence Development in Daejeon, Korea. His research fields are dynamic systems measurement and control, satellite systems, navigation systems and smart materials.     

Investigation of variations of lubricating oil diluted by post-injected fuel for the regeneration of CDPF and its effects on engine wear

The purpose of the present study was to investigate the effects of oil diluted by post-injected fuel for CDPF regeneration on engine wear and to find out the characteristic variation of diluted oil according to operating conditions. Experimental studies were made on a 2700 cc, 5 cylinder engine with an after-treatment system. Fuel content in oil increased according to the increase in the duration of post injection. A fuel dilution chart was made to predict the existing fuel content in used oil. The oil analysis method using this chart was validated through the comparison of the results analyzed by GC. The oil contamination by the post-injected fuel caused the quantity of blow-by gas and engine wear to increase and main gallery pressure to decrease. This paper was recommended for publication in revised form by Associate Editor Kyoung Doug Min Bong-Ha Song received a B.S. degree in Mechanical Engineering from Konkuk University in 1999. He received a M.S. degree from Yonsei University in 2002. He then went to Ajou University to get a Ph.D degree. Bong-Ha Song is currently a student at the School of Mechanical Engineering at Ajou University in Suwon, Korea. Yun-Ho Choi received a B.S. degree in Mechanical Engineering from Seoul National University in 1978. He then went on to receive his M.S. and Ph.D. degrees from Pennsylvania State University in 1984 and 1988, respectively. Dr. Choi is currently a professor at the Division of Mechanical Engineering at Ajou University in Suwon, Korea. Dr. Choi’s research interests are in the area of Computational Fluid Dynamics, Thermal Propulsion Systems Modeling and Two Phase Flows.     

A study on the optimization method for a multi-body system using the response surface analysis

An optimization method, which minimizes the characteristic value of a system using response surface analysis, is presented. Plackett-Burman design is used as a screening method. Using the response surface analysis, second order recursive model function is estimated as an objective function. To verify the reliability of the model function, an F-test based on the analysis of variances table is used. Lastly, the sequential quadratic-programming method is used to find the value of design parameters. By applying the preceding procedure to a multi-body dynamic model, the optimization process presented in this study is verified. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Sung Pil Jung received a B.S. degree in Mechanical Engineering from Ajou University in 2006. Currently he is a Ph.D candidate at Ajou University in Suwon, Korea. Mr. Jung’s research interests are in the area of multi-body & structural dynamics, optimization and computer aided engineering. Tae Won Park received a B.S. degree in Mechanical Engineering from Seoul University. He then went on to receive his M.S. and Ph.D. degrees from the University of Iowa. Dr. Park is currently a Professor at the School of Mechanical Engineering at Ajou University in Suwon, Korea.     

Prediction of deformations of steel plate by artificial neural network in forming process with induction heating

To control a heat source easily in the forming process of steel plate with heating, the electro-magnetic induction process has been used as a substitute of the flame heating process. However, only few studies have analyzed the deformation of a workpiece in the induction heating process by using a mathematical model. This is mainly due to the difficulty of modeling the heat flux from the inductor traveling on the conductive plate during the induction process. In this study, the heat flux distribution over a steel plate during the induction process is first analyzed by a numerical method with the assumption that the process is in a quasi-stationary state around the inductor and also that the heat flux itself greatly depends on the temperature of the workpiece. With the heat flux, heat flow and thermo-mechanical analyses on the plate to obtain deformations during the heating process are then performed with a commercial FEM program for 34 combinations of heating parameters. An artificial neural network is proposed to build a simplified relationship between deformations and heating parameters that can be easily utilized to predict deformations of steel plate with a wide range of heating parameters in the heating process. After its architecture is optimized, the artificial neural network is trained with the deformations obtained from the FEM analyses as outputs and the related heating parameters as inputs. The predicted outputs from the neural network are compared with those of the experiments and the numerical results. They are in good agreement. This paper was recommended for publication in revised form by Associate Editor Youngseog Lee Truong-Thinh Nguyen received the B.S and M.S degrees from Ho Chi Minh city National University, Viet Nam, in 1997 and 2000, respectively. Now, he is a doctoral candidate in the Department of Mechanical Engineering at Chonnam National University, Korea. His research interests are Induction Heating, Thermal deformations, applications of Neural Network and Fuzzy logic in Industry, intelligent control. Young-Soo Yang received a B.S. degree in Mechanical Engineering from Sungkyunkwan University in 1985. He then went on to receive his M.S. and Ph.D. degrees from KAIST in 1987 and 1991, respectively. Dr. Yang is currently a Professor at the School of Mechanical Engineering at Chonnam National University in Gwangju, Korea. He research interests are in the area of weld structure. Kang-Yul Bae is a Professor of Mechatronics Engineering Department at Jinju National University in Jinju, Korea. He received a B.S. degree in Mechanical Engineering from Busan National University in 1984. He also holds the following degrees of M.S. in Production Engineering and Ph.D. in Mechanical Engineering from KAIST in 1986 and 1994, respectively. He has industrial experience from 1986 to 1998 at Hyundai Heavy Industries, Co. Ltd. as a senior researcher. His teaching and research areas include manufacturing processes, automation, and mechatronics. Sung-Nam Choi received a B.S. and a M.S. degree in Department of Mechanical Engineering from Chonnam National University in 1989 and 1991. He then complete doctor course from the same University in 2006. He is currently a Senior Researcher at Non-Destructive Evaluation Center at Korea Electric Power Research Institute in Daejon, Korea. His research interests are in the area of weld integrity, fracture mechanics, and automated ultrasonic examination.     

Development and validation of stereoscopic micro-PTV using match probability

A stereoscopic micro-PTV (particle tracking velocimetry) technique based on 2-frame PTV using match probability was developed. This method measures not only a two-dimensional velocity field but also the out-of-plane velocity component in micro fluid flow. A validation study of SMPTV by using a simulated flow model and a real micro jet flow was performed to verify the accuracy and feasibility of the method. The effects of different kinds of microscopes and the out-of-focus effect were also investigated. All test results were compared with the SMPIV method in order to evaluate the performance. The results showed that the SMPTV method using a CMO type microscope accurately measured the micro flow with the lowest bias error and higher spatial resolution than the SMPIV method. This paper was recommended for publication in revised form by Associate Editor Haecheon Choi Hyoung-Bum Kim received his M.Sc. and Ph.D. in Mechanical Engineering from POSTECH in 2000. He worked in the Department of Mechanical Engineering of the University of Colorado, Boulder till 2004 as a post-doctoral researcher and then in 2004 joined the School of Mechanical and Aerospace Engineering at Gyeongsang National University as an assistant professor. His research interests are in flow measurement and control using optical and ultrasound method, turbulent shear flow, flow instability and bio-fluid flow. Cheong-Hwan Yu received his B.Sc. degree in Mechanical Engineering in 2007 from Gyeongsang National University and is now a master’s degree student at the Graduate School of Mechanical and Aerospace Engineering, Gyeongsang National University. His research interest is micro flow measurement and POD analysis. Jong-Hwan Yoon received his M.Sc. and Ph.D. in Mechanical Engineering from POSTECH in 2003. He worked in Doosan Heavy Industry till 2004 and then joined the School of Automotive, Industrial and Mechanical Engineering at Daegu University. He is interested in 3-component flow measurement techniques using optical methods and flow induced noises and vibrations.     

Analysis and design study of LCD transfer robot using dynamic simulation and experiment

Recently, the size of raw glass has been greatly increased in the new generation Liquid Crystal Display (LCD) technology. To handle bigger and heavier glasses, it is necessary to develop a large scale LTR (LCD Transfer Robot) to support various complicated LCD fabrication processes. This adjustment will result in difficult design problems such as vibration, handling accuracy deterioration, and high stress due to heavier dynamic loads. In turn, these will result in inaccurate transfer motion and fatigue cracks. In this paper, the dynamic simulation technique is introduced to validate a baseline design and to propose new and improved designs for the best performance of heavy-scaled LCD transfer robots. The dynamic models and analysis results were verified by real experiments including strain measure test and motor power test. Using the verified simulation model, some dynamic situations such as the robot’s emergency stop and free fall situation, which were not impossible to test using the real proto robot, were analyzed and predicted using the simulation model. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Jong-Hwi Seo received a B.S. M.S. and Ph.D. degrees from Ajou University in 1998, 2000 and 2005, respectively. He is currently a senior engineer in Mechatronics and Manufacturing Technology Center of Samsung Electronics Co. His research interests are in the area of multibody dynamics, robotics and mechanism design. Jae Chul Hwang received a B.S., M.S., and Ph.D. degrees in mechanical engineering from Seoul National University, Korea, in 1996, 1998, and 2002, respectively. He is currently a senior engineer in Mechatronics and Manufacturing Technology Center of Samsung Electronics Co., Ltd. His research interests are in the area of kinematics and dynamics of serial and parallel kinematic robot. Yong-Won Choi received a M.S degree in Mechanical Engineering from Korea University in 1993. He has worked for Samsung Electronics, Ltd from 1993 and is currently a principle engineer at Robot Mechanism Part in Mechatronics and Manufacturing Technology Center of Samsung Electronics Co. He is interest in the area of robotics, control and mechanism design. Hong Jae Yim received B.S. and M.S degrees in mechanical engineering from Seoul National University, Korea, in 1979, and 1983, respectively. He received Ph.D degree from Univ. of Iowa, USA. He is currently a professor in School of Mechanical & Automotive Engineering, Kookmin University. His research interests are in the area of computer aided kinematics and dynamics of mechanical systems.     

Effect of partial rotor-to-stator rub on shaft vibration

The effect of partial rotor-to-stator rubbing is investigated both experimentally and analytically. It is found that due to rubbing the measured vibration signal is distorted showing a flattened portion in the waveform. Spectral analysis indicates that the synchronous component is generally attenuated as a result of rubbing-introduced-friction. It is also indicated that light rubbing induced vibrations are characterized by harmonics at frequencies equal to 1x rev., 2x rev., and 3x rev. Whereas, severe rubbing is identified experimentally by a spectrum containing subharmonics at 1/3 and 2/3 of the rotational frequency. Because of the stiffening effect of rubbing on the rotor, the resonance frequency increases. In general, the analytical results show good agreement with experimental data. This paper was recommended for publication in revised form by Associate Editor Eung-Soo Shin Mohamed A. Abuzaid received his B.S. degree in Mechanical Engineering from Cairo University, Cairo, Egypt, in 1970. He then went on to receive his M. Eng. degree from Carleton University, Ottawa, Canada in 1979, and his Ph.D. degree from Cairo University, Egypt in 1987. Dr. Abuzaid is currently a lecturer at the Department of Mechanical Engineering Technology at the Public Authority for Applied Education & Training in Kuwait. His research interests are in the area of dynamics of rotating machines. Mohamed E. Eleshaky received his B.Sc. and M.Sc. degrees in Mechanical Engineering from Alexandria University, Alexandria, Egypt, in 1982 and 1987, respectively. He then went on to receive a Ph.D. degree from Old Dominion University, Virginia, U.S.A in 1992. Dr. Eleshaky is currently an Assistant Professor at the Department of Mechanical Engineering Technology at the Public Authority for Applied Education & Training in Kuwait. He is also on leave from the Mechanical Engineering Department, Faculty of Engineering, Alexandria University, Egypt. His research interests are in the areas of aerodynamic design optimization and sensitivity analysis, computational fluid dynamics, jet flows, tribology, and vibrations. Mohamed G. Zedan is an assistant professor in the Mechanical Engineering Dept., College of Technological Studies, Kuwait. He was a Staff Engineer in the gas turbine engine department, Textron Lycoming, Stratford, CT, U.S.A. He was a Sr. Research Engineer in the gas turbine engine department, Allison Gas Turbine GMC, IN, U.S.A. He has a B.Sc. degree in Mechanical Engineering from Cairo University, Egypt. He has a M.Sc. and Ph.D degrees in Mechanical Engineering from University of Waterloo, Canada.     

The effect of additional equilibrium stress functions on the three-node hybrid-mixed curved beam element

To develop an effective hybrid-mixed element, it is extremely critical as to how to assume the stress field. This research article demonstrates the effect of additional equilibrium stress functions to enhance the numerical performance of the locking-free three-node hybrid-mixed curved beam element, proposed in Saleeb and Chang’s previous work. It is exceedingly complicated or even infeasible to determine the stress functions to satisfy fully both the equilibrium conditions and suppression of kinematic deformation modes in the three-node hybrid-mixed formulation. Accordingly, the additional stress functions to satisfy partially or fully equilibrium conditions are incorporated in this study. Several numerical examples for static and dynamic problems confirm that the newly proposed element with these additional stress functions is highly effective regardless of the slenderness ratio and curvature of arches in static and dynamic analyses. This paper was recommended for publication in revised form by Associate Editor Maenghyo Cho Jin-Gon Kim graduated from the Seoul National University in 1991, majoring in Mechanical Engineering. He received Master’s degree and Ph.D. degree in Mechanical Engineering at the Seoul National University in 1993 and 1998, respectively. He has worked for Samsung Electronics for three years from March 1998 to February 2001, and is currently in the School of Mechanical and Automotive Engineering at Catholic University of Daegu. Main research interests include structural/impact anlyses, advanced finite element method and CAE. Yong Kuk Park graduated from the Seoul National University in 1987, majoring in Metallurgical Engineering. He received Master’s degree in Industrial and Systems Engineering at the University of Michigan in 1988, and Ph.D. degree in Manufacturing Engineering at the Ohio State University in 1995. He has worked for Samsung Motor Co., and is currently in the School of Mechanical and Automotive Engineering at Catholic University of Daegu, teaching Manufacturing Design, Statistical Quality Control, Casting and Plasticity, Forging and Press Forming, Advanced Studies in Plasticity. Main research interests include advanced mechanical design, manufacturing processes, design of manufacturing systems and statistical process control.     

Phase of acoustic impedance and performance of standing wave thermoacoustic coolers

Investigations on the relations between the phase angle of the acoustic impedance at the driver piston and the system performance of a standing wave thermoacoustic cooler were performed. The system performance measured at a fixed acoustic power showed that the coefficient of performance of the standing wave thermoacoustic cooler increases as the phase angle increases when the stack temperature span is relatively low. The results were consistent with the simulation results obtained from DELTAE, a computer code based on linear thermoacoustic theory. Analysis on the temperature profiles along the stack showed that the cooling efficiency (COP) of the system could be decreased or increased as the phase angle of the acoustic impedance at the driver piston changes depending on the stack temperature spans. This paper was recommended for publication in revised form by Associate Editor Yeon June Kang Insu Paek received the B.S. degree in Mechatronics Engineering from Kangwon National University, Chuncheon, Korea, in 1997, the M.S. degree in Mechanical Engineering from the University of Texas at Austin, USA, in 2000, and the Ph. D. degree in Mechanical Engineering from Purdue University, West Lafayette, USA, in 2005. He worked as a postdoctoral researcher in Purdue University and McGill University in 2006 and 2007. He is currently a faculty member in the Department of Mechatronics Engineering, Kangwon National University, Chuncheon, Korea. His research interests include thermoacoustic cooling and power generation, solar heat driven absorption cooling., and wind power. Luc Mongeau received the B.S. and M.S. degrees in mechanical engineering from the University of Montreal, QC, Canada, in 1984 and 1986, respectively, and the Ph. D. degree in Acoustics from Pennsylvania State University, University Park, USA, in 1990. He is currently a professor in the Department of Mechanical Engineering at McGill University, Montreal, QC, Canada. He has published over 50 archival journal publications on various topics related to acoustics and noise control. His research activities are in the flow and turbomachinery noise areas, as well as in the areas of voice production, and thermoacoustic refrigeration. James E. Braun received the B.S. degree in Mechanical Engineering from the University of Massachusetts, USA, in 1976, and the M.S. and Ph. D. degrees in Mechanical Engineering from the University of Wisconsin, Madison, USA, in 1980 and 1988, respectively. He is currently a professor in the Department of Mechanical Engineering, Purdue University, West Lafayette, USA. Professor Braun’s research combines the use of computer modeling, optimization, and experiments to study and improve the performance of thermal systems. He has published over 140 papers. Professor Braun is currently an associate editor for the international journal of HVAC&R Research. Shin You Kang received the B.S. and M.S. degrees in the Department of Mechanical Design from Seoul National University, Seoul, Korea, in 1982, and 1986, respectively. He then received the Ph.D. in Mechanical Engineering at the same university in 1992. Professor Kang is currently a professor in the Department of Mechatronics Engineering, Kangwon National University, Chuncheon, Korea. His research interests include mechanical structure design, crash analysis, optimal design, computational structure analysis and evaluation.     

The effect of blade angle on the flow and pressure distributions in the vicinity of the diffuser blades of a room air conditioner

Many studies on air-conditioning systems are more focused on the individual thermal comfort rather than the thermal efficiency, due to an increase in health concerns. There are several factors influencing the thermal comfort, such as temperature, humidity, convection and air movement, etc. Numerical analyses were performed to investigate the effect of blade angle on the flow characteristics in the vicinity of diffuser blades of a room air conditioner (RAC), with three different blade discharge angles of 45.1°, 58.6° and 116°. We used the commercial code FLUENT to calculate the two-dimensional steady thermal flow fields with different impeller rotational velocities. The angular velocities were located within the range from 900 rpm to 1200 rpm. Turbulence closure was achieved using a standard k-ɛ model. A moving reference frame (MRF) approach was adopted to simulate the flow field generated by the impeller in an RAC. The results were graphically depicted with various geometrical configurations and operating conditions. This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008. Youn-Jea Kim received his B.S. degree in Mechanical Engineering from Sungkyunkwan University, Korea, in 1982. He then received his M.S. and Ph.D. degrees from the State University of New York at Buffalo in 1987 and 1990, respectively. Dr. Kim is currently a Professor at the School of Mechanical Engineering at Sungkyunkwan University in Korea. Dr. Kim’s research interests include gas dynamics, MEMS, and fluid-machineries, etc.     

Suspension mechanism simulation and optimization considering multiple disciplines

A new method in suspension mechanism design considering two coupled disciplines, dynamics and structure, has been proposed in this paper. One of the decomposition methods widely used in multidisciplinary design optimization (MDO)—collaborative optimization (CO) has been used in this work. CO is a bi-level optimization architecture that preserves the autonomy of individual disciplines. In subsystem level, these two disciplines share the same model from CAD models in preprocess stage. Data file and interface have been explained and implemented in detail. The result obtained has shown that it works well and the time cost is less than before. This paper was recommended for publication in revised form by Associate Editor Jeong Sam Han Hao Wang received his B.Sc. degree of mechatronic engineering in 2005 in Automation Science and Electrical Engineering at Beihang University and he is a Ph.D. candidate at Beihang University. His research interests are in the area of Multidisciplinary Design Optimization, computer integrated manufactory system and product lifecycle management. Shaoping Wang received her BS, MS and Doctoral degree in mechatronic engineering from Beihang University in 1988, 1991 and 1994. She is a professor of mechatronic engineering in school of automation science and electrical engineering at Beihang University. Her research interests include reliability engineering, product lifecycle management, fault diagnosis, fault tolerant control, system modeling and simulation. Mileta M. Tomovic received a B.S. degree in Mechanical Engineering from University of Belgrade in 1979. He then went on to receive his M.S. degree and Ph.D. degrees from MIT and University of Michigan in 1981 and 1991, respectively. Dr. Tomovic is currently a Professor at Batten College of Engineering and Technology, Old Dominion University in Norfolk, U.S. Dr. Tomovic’s research interests are in the area of system dynamics and controls, manufacturing processes, design optimization, collaborative design, PLM, modeling of rapid prototyping and fast free form fabrication methods, and web-based multi-user platform development.     

The kinematic design of a planar-cam type pick-and-place device

The planar-cam type pick-and-place device can clearly and effectively achieve the desired curvilinear motion of its end effector, and it can be designed and fabricated easily. By employing the concept of velocity instant center, the cam profiles, the paths of cutters, the pressure angles and the radii of curvature of the dual cams of the planar-cam type pick-and-place device can be expressed parametrically. The cam profiles may have concave portions, and each minimum radius of curvature of the concave portion of the dual cam profiles is the upper bound of the grinding-wheel radius that may not cause undercutting. This paper was recommended for publication in revised form by Associate Editor Jeonghoon Yoo Wen-Tung Chang received his Bachelor and Master degrees in Mechanical and Marine Engineering from Nation Taiwan Ocean University in 2000 and 2002, respectively. He then went on to receive his Ph.D. degree in Power Mechanical Engineering from National Tsing Hua University in 2007. Dr. Chang is currently a Postdoctoral Researcher of Opto-Mechatronics Technology Center at National Taiwan University of Science and Technology in Taipei, Taiwan. His research interests include kinematics and dynamics of machinery, mechanism and machine design, and opto-mechatronic system. Long-Iong Wu received his Ph.D. degree in Mechanical Engineering from National Cheng Kung University in 1987. Dr. Wu is currently a Professor of Department of Power Mechanical Engineering at National Tsing Hua University in Hsinchu, Taiwan. His research interests include kinematics of machinery, mechanism design, and precision machine design. His main research activities in his laboratory are linkage mechanism design and cam mechanism design. In the past, Dr. Wu has worked for China Steel Corp., and San Shing Fastech Corp. where he was responsible for designing high speed nut formers. Chun-Hsien Liu received his Master degree in Mechanical Engineering from Nation Chiao Tung University in 1996. He is currently a Lecturer and also a Ph.D. Candidate of Department of Power Mechanical Engineering at National Tsing Hua University in Hsinchu, Taiwan. Mr. Liu has worked for over twenty years at Industrial Technology Research Institute (ITRI), where he was responsible for designing packaging equipments in semiconductor and flat panel display industry. He is currently the Deputy Director of Intelligent Systems Engineering Division of Mechanical and Systems Research Laboratories at ITRI.     

Asymmetric loading of erector spinae muscles during sagittally symmetric lifting

Functional asymmetry is among the multitude of risk factors for low-back pain (LBP), the most common injury under general industrial and agricultural conditions. However, previous studies showed that normal healthy individuals exhibit some functional asymmetry, indicating that not all asymmetry causes LBP. Therefore, the threshold value that is able to discriminate between normal and pathological situations is used as critical information to predict LBP. As a preliminary study to find threshold, the purpose of this study is to quantify the magnitude of bilateral asymmetries of erector spinae muscle forces of a healthy group during sagittally symmetric lifting. Ten healthy male subjects with no history of back pathology participated in this study, which collected motion capture, force data, and electromyography signals from six infrared cameras (MCam2, Vicon), two force platforms (AMTI), and surface EMG (BME Korea). In order to quantify the magnitude of bilateral asymmetry in the trunk muscle forces, we used 3D linked segment and EMG-assisted modeling approaches, both of which were verified based on their recapitulation of previously-proposed models. The results indicated that each muscle force in the lumbar region exhibited asymmetry during the entire lifting process. In particular, the erector spinae muscle forces exhibited an approximate 24% difference between bilateral sites (p<0.05). The results of this study provided data from normal individuals by which to identify pathological situations and predict LBP incidence within general industrial and agricultural conditions. This paper was recommended for publication in revised form by Associate Editor Young Eun Kim Ahn Ryul Choi received his B.S. and M.S. degrees in Bio-Mechatronic engineering from Sungkyunkwan University in 2005 and 2007, respectively. Ahn-Ryul Choi is currently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling and simulation. Tae Sun Yun received his B.S. and M.S. degrees in mechanical engineering from Korea Aero-space University in 2005 and 2007, respectively. Tae-Sun Yun is currently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling and simulation. Kyung Suk Lee is a specialist with many years experience of the agricultural health and safety in Republic of Korea. Her personal interests and most publications are in various hazards including ergonomic risk factors and management system set-up in local and national system. She has been doing her researches in National Academy of Agricultural Science (NIAST). She has also managed lots of network system that is composed of scientists, national officer, farmers union for agricultural safety and hearth. She is currently in the Group who is consultant with “safe farm model intervention” in local areas and national safety and health. Kyoung Kee Min received his Ph.D degree Sungkyunkwan University in 2008. Dr. Min is currently a researcher at the Bio-Mechatronics Center in Sungkyunkwan University. Dr. Min’s research interests are in the area of disease classification using artificial neural network, digital human modeling & control. Heon Hwang received his Ph.D. degree majoring in Engineering Science from the Louisiana State University, Baton Rouge in 1988. Dr. Hwang is currently a Professor at the Department of Bio-Mechatronic Engineering, Sung-kyunkwan University in Korea. Dr. Hwang’s research interests are intelligent motion control based on human motor and brain behavior, tele-operative biorobotic system and interface, and real time on-line bio-image processing and bio-sensing. Ki Young Lee received a B.S., M.S. and Ph D. degree in Electronic Engineering from Myongji University in 1984, 1986 and 1992, respectively. Since 2004, he also has interested to study on Bioengineering, and finished the Ph D. course from Sungkyunkwan University. Dr. Lee is currently a Professor at the Department of Biomedical Engineering at Kwandong University in Kangneung, Korea. His research interests are the area of Bioelectronics and Bio-signal processing. Euichaul Oh received a B.S. degree in Pharmacy (1983) and a M.S. degree in Physical Pharmacy (1985) from Seoul Nation University, respectively. He then acquired his Ph.D. degree in Pharmaceutics from the University of Iowa in 1996. Dr. Oh is currently a Chief Scientific Officer at the R&D Center of Kuhnil Pharm. In Seoul, Korea. He had worked at the pharmaceutical companies in USA as a Senior Research Scientist for 10 years. He is currently serving as an Editor Board of the Journal of Korean Pharmaceutical Sciences. Dr. Oh’s research interests are in the areas of Drug Delivery System, Physical and Industrial Pharmacy and Pharmaceutical Technology and Engineering. Joung Hwan Mun received his Ph.D. degree majoring in mechanical engineering from the University of Iowa in 1998. Dr. Mun is currently a Professor at the Department of Bio-Mechat-ronic engineering at Sungkyun-kwan University in Suwon, Korea. He is currently serving as a director of the Bio-Mechatronics center with regard to an international IMS project. Dr. Mun’s research interests are in the area of digital human modeling, sports biomechanics, bio-electronics and digital factory for human oriented production system.