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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 26, Issue 12 - Dec 2009
Volume 26, Issue 11 - Nov 2009
Volume 26, Issue 10 - Oct 2009
Volume 26, Issue 9 - Sep 2009
Volume 26, Issue 8 - Aug 2009
Volume 26, Issue 7 - Jul 2009
Volume 26, Issue 6 - Jun 2009
Volume 26, Issue 5 - May 2009
Volume 26, Issue 4 - Apr 2009
Volume 26, Issue 3 - Mar 2009
Volume 26, Issue 2 - Feb 2009
Volume 26, Issue 1 - Jan 2009
Selecting the target year
Five-Axis Machine Tools - Test and Evaluation Technology
Gim, Tae-Weon ; Ha, Jae-Yong ; Kim, Tae-Hyung ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 7~11
Machining Efficiency Enhancement Algorithms for 5-axis milling
So, Bum-Sik ; Ko, Tae-Jo ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 12~17
Tool-path Generation for 5-axis Machining
Park, Jung-Whan ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 18~24
Application of 5-axis Machining - Laser Engraving, Molding Die Machining
Kim, Hyung-Jung ; Wie, Kyung-Hoon ; Ahn, Sung-Hoon ; Jun, Cha-Soo ; Lee, Sang-Hoon ; Lee, Jung-Geun ; Cho, Hyeon-Uk ; Park, Jung-Whan ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 25~31
Cubic Tangible User Interface Development for Mobile Environment
Ok, Soo-Yol ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 32~39
Most mobile devices provide limited input interfaces in order to maximize the mobility and the portability. In this paper, the author proposes a small cubic-shaped tangible input interface which tracks the location, the direction, and the velocity using MEMS sensor technology to overcome the physical limitations of the poor input devices in mobile computing environments. As the preliminary phase for implementing the proposed tangible input interface, the prototype design and implementation methods are described in this paper. Various experiments such as menu manipulation, 3-dimensional contents control, and sensor data visualization have been performed in order to verify the validity of the proposed interface. The proposed tangible device enables direct and intuitive manipulation. It is obvious that the mobile computing will be more widespread and various kinds of new contents will emerge in near future. The proposed interface can be successfully employed for the new contents services that cannot be easily implemented because of the limitation of current input devices. It is also obvious that this kind of interface will be a critical component for future mobile communication environments. The proposed tangible interface will be further improved to be applied to various contents manipulation including 2D/3D games.
Development of Dynamic ID Allocation Algorithm for Real-time Quality-of-Service of Controller Area Network
Lee, Suk ; Ha, Kyoung-Nam ; Lee, Kyung-Chang ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 40~46
Recently CAN (Controller Area Network) is widely used as an in-vehicle networking protocol for intelligent vehicle. The identifier field (ID) of CAN is used not only to differentiate the messages but also to give different priorities to access the bus. This paper presents a dynamic 10 allocation algorithm in order to enhance the real-time quality-of-service (QoS) performance. When the network traffic is increased, this algorithm can allocate a network resource to lower priority message without degradation of the real-time QoS performance of higher priority message. In order to demonstrate the algorithm's feasibility, message transmission delays have been measured with and without the algorithm on an experimental network test bed.
Landing Performance of a Quadruped Robot Foot Having Parallel Linked Toes on Uneven Surface
Hong, Yeh-Sun ; Yoon, Seung-Hyeon ; Kim, Min-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 47~55
In this study, a robot foot having toes for firm stepping on uneven surface is proposed. The toes are connected to the lower leg by parallel links so that the lower leg can rotate in the rolling and pitching directions during stance phase without ankle joint. The landing performance of the foot on uneven surface was evaluated by relative comparison with that of the most common foot making point contact with the walking surface, since the test conditions considering real uneven surface could be hardly defined for its objective evaluation. Anti-slip margin(ASM) was defined in this study to express the slip resistance of a robot foot when it lands on a projection with half circular-, triangular- or rectangular cross section, assuming that uneven surface consists of projections having these kind of cross sections in different sizes. Based on the ASM analysis, the slip conditions for the two feet were experimentally confirmed. The results showed that the slip resistance of the new foot is not only higher than that of the conventional point contact type foot but also less sensitive to the surface friction coefficient.
Study on Optimal Design and Walking gait of Parallel Typed Walking Robot
Kim, Chi-Hyo ; Park, Kun-Woo ; Kim, Tae-Sung ; Lee, Min-Ki ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 56~64
This paper presents a parallel typed walking robot which can walk in omni-direction and climb from a floor to a wall. We design a six D.O.F leg mechanism composed of three legs, which form a parallel mechanism with a base and a ground to generate arbitrary poses. Optimal design is conducted to maximize the walking space and the dexterity, which are normalized by the stroke of leg. Kinematic parameters are found to maximize the weighted optimal objectives. We design a triple parallel mechanism robot by inserting Stewart platform between the upper leg mechanism and the lower leg mechanism and examine the gaits when the robot walks on the ground and climbs from a floor to a wall. The analysis of walking space and dexterity for each gait shows that the triple parallel walking robot has a large walking space with a large stability region. We explore the possibility that the robot can climb from a floor to a wall. Investigating the gaits for the six steps proves that the robot can lift the foot up to the wall by combining the orientational walking space generated by three parallel mechanisms.
A Study on the LQG Precision Tension Control of a Dancer System for a Production of Printed Electronics in Roll-to-roll Systems
Seong, Jin-Woo ; Kang, Hyun-Kyoo ; Shin, Kee-Hyun ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 65~73
For mass production of printed electronics in roll-to-roll fashion, precision tension control is important to reduce register errors. Register error should be minimized within several to tens of microns for many electronic devices to be manufactured through printing technology. In order to achieve this goal, tension disturbance must be attenuated before printing process within a certain range. In this paper, a certain tension range which allows maintaining register error within 10 micron was defined with specific operating conditions. A LQG controller was proposed instead of the conventional PI controller for precision tension control using a multivariable feedback. A guideline to determine design parameters for calculating LQ gain was proposed. The proposed LQG controller was compared to both PI controller and LQ regulator with white noise by numerical simulations. Results showed that the proposed LQG controller was effective for attenuating tension disturbance with white noise.
Analysis of Fluid Flow in the Linear Cell Source for Organic Semiconductor Thin Film Deposition
Kwak, In-Chul ; Yang, Young-Soo ; Choi, Bum-Ho ; Kim, Young-Mi ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 74~80
This paper presents a study on fluid flow analysis of organic semiconductor thin film deposition process using the computational numerical method. In the production process, the thickness of deposited organic thin film depends on distribution of nozzle size in the linear cell system, so we analyze to decide the optimal nozzle system for uniform thickness of organic thin film. The results of deposited thickness of thin film by numerical analysis are in good agreement with those of the experimental measurements.
Deformation Analysis of Miniature Metal Bellows Charged Nitrogen for Temperature Change to Cryogenic Condition
Lee, Seung-Ha ; Lee, Tae-Won ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 81~88
Bellows is used to control temperature of a Joule-Thomson micro cryocooler. It is made of Nickelcobalt alloy that retains mechanical properties from cryogenic temperature to temperature of 570K. The geometry of bellows is an axisymmetric shell and Nitrogen with high pressure was charged at temperature of 293K. During cool-down process, the pressure and volume of Nitrogen are changed and must be satisfied with state equation. At cryogenic temperature, Nitrogen can exist as a part liquid and part vapor. Pressure-density-temperature behavior under this vaporliquid phase equilibrium is closely given by the Modified-Benedict-Webb-Rubin(MBWR) state equation. To evaluate deformation of bellows for temperature change, the numerical calculation of the volume within bellows and finite element analysis of bellows under internal pressure were iteratively performed until MBWR state equation is satisfied. The numerical results show that deformation of the bellows can be analyzed by the present method in a wide range of temperature including cryogenic temperature.
Superplstic Forming Analysis of Duplex Stainless Steel with Finite Element Method
Park, Ji-Won ; Kang, Seok-Bong ; Hwang, Yeong-Jin ; Lee, Seok-Soon ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 89~96
In recent years, there has been a considerable interest in the application of super plastic forming in the aircraft and automotive industries. This requires a detailed design of the technological process in order to exploit its peculiar potentialities better. Nowadays, the finite element method is used to plan the sheet metal forming processes whose simulation requires determination of material constants for super plastic materials. The present work is aimed to show a simple method to characterize super plastic materials duplex stainless steel which was formed by a constant gaspressure to hemispheres with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of hemispheres were measured for applying the pressures. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to follow closely the flow stress - strain rate relationship obtained from the strain rate change tests performed at the same temperature.
A Patent Analysis on the Battery and Rechageable System of the Plug-in Hybrid Car
Chang, Jin-Geon ; Lee, Young-Shin ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 97~107
Recent technologies of the car are focused on improving vehicle's fuel efficiency and developing alternative energy sources. These technologies bring on the development of hybrid car. On the other hand, because of short driving distance, low efficiency of charging and high price, energy storage system need to improve the storage capability. It is very important to understand the existing technologies, grasp the existing patent and establish the technical target to improve the energy storage system. In this paper, technology trends of energy storage system of the hybrid car are analyzed. This study was based on the applied and registered patent in Korea, Japan, U.S.A and Europe until December 2008. The analyses are divided into two categories: a battery system and charging system of the hybrid car. The facts of the level of technology, trends of the R&D of leading companies, key patents, blank of the technology were analyzed. Finally the future R&D strategy of hybrid car are established.
Micromachining Using Hybrid of Laser Beam and Electrical Discharge Machining
Kim, San-Ha ; Chung, Do-Kwan ; Kim, Bo-Hyun ; Oh, Kwang-Hwan ; Jeong, Sung-Ho ; Chu, Chong-Nam ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 108~115
Although nanosecond pulsed laser drilling and milling are rapid and non-wear processes in micromachining, the quality cannot meet the precision standard due to the recast layer and heat affected zone. On the other hand, electrical discharge machining (EDM) is a well-known high precision machining process in micro scale; however, the low material removal rate (MRR) and tool wear remain as drawbacks. In this paper, hybrid process of laser beam machining (LBM) using nanosecond pulsed laser and micro EDM was studied for micro drilling and milling. While the quality of the micro structure fabricated by this hybrid process remains as high as direct EDM, the machining time and tool wear can be reduced. In addition, variable depth of layer was introduced as an effective method improving efficiency of hybrid milling.
Analysis on the Effect of Lordosis Changes at Lumbar Joint using 3-dimensional Musculoskeletal Model
Bae, Tae-Soo ; Kim, Shin-Ki ; Ryu, Je-Chung ; Mun, Mu-Seong ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 116~121
It is important to consider lumbar lordotic angle for setup of training program in field of sports and rehabilitaton to prevent unexpected posture deviation and back pain. The purpose of this study was to analyze the biomechanical impact of the level of lumbar lordosis angle during isokinetic exercise through dynamic analysis using a 3-dimensional musculoskeletal model. We made each models for normal lordosis, excessive lordosis, lumbar kyphosis, and hypo-lordosis according to lordotic angle and inputted experimental data as initial values to perform inverse dynamic analysis. Comparing the joint torques, the largest torque of excessive lordosis was 16.6% larger and lumbar kyphosis was 11.7% less than normal lordosis. There existed no significant difference in the compressive intervertebral forces of each lumbar joint (p>0.05), but statistically significant difference in the anterioposterior shear force (p<0.05). For system energy lumbar kyphosis required the least and most energy during flexion and extension respectively. Therefore during the rehabilitation process, more efficient training will be possible by taking into consideration not simply weight and height but biomechanical effects on the skeletal muscle system according to lumbar lordosis angles.
Effects of Unloading induced Denervation on Trabecular Bone of Growing Mice; Gender-difference
Seo, Dong-Hyun ; Ko, Chang-Yong ; Kang, Sun-Young ; Lim, Do-Hyung ; Kim, Han-Sung ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 122~128
The aim of this study was to investigate, through a longitudinal tracking, whether gender influences morphological characteristics on trabeucular bone of tibia during unloading. 12 male and 15 female ICR mice at 6 week of age were used and randomly allocated into two groups in each gender; unloading and normal group, respectively Mice in unloading group were operated on denervation (sciatic neurectomy). The tibiae were scanned by using in vivo micro-computed tomography (micro-CT) at 0 day (before denervation) and after 14 days. Structural parameters and BMD on tibia were measured. In female, BV/TV (65%), Tb. Th (5%), Tb.N (61%) and BMD (62%) were significantly decreased and BS/BV (17%), Tb.Sp (54%), SMI (19%) and Tb.Pf (75%) were significantly increased after unloading (p<0.05). In male, BV/TV (1%) and Tb.N (10%) were significantly decreased and SMI (5%) was significantly increased after unloading (p<0.05). In addition, trabeuclar bone loss of female was significantly bigger than that of male (p<0.05). These results indicated that effects of unloading on trabecular bone in growing mice might have difference between female and male, although unloading result in loss of quantity and quality on trabecular bone both female and male.
Development of Data Acquisition System using the Backscattered X-ray
Hwang, In-Ho ; Jung, Jin-Seok ; Yuk, Sun-Woo ; Yoo, Sun-Kook ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 10, 2009, Pages 129~133
Considerable attention has been focused on digital X-ray systems with transmission. However, only a few attempts have been made using X-ray backscatter systems. This study developed a Data Acquisition System (DAS) for backscattered X-rays. The imaging system used X-ray backscatter at low energy levels, which has unique advantages in terms of acquiring information that cannot be obtained using the transmission system. Such systems are of potential benefit in the medical, industrial, security and military fields because of its practical benefits and the low doses used. The developed system is a similar body scan system. Experiments were carried out using a several metal materials and a fish, which produces results similar to those obtained using the human body during X-ray testing.