• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.226-232
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• 2000

This paper develops a finite element model for studying the crashworthiness analysis of a mid-size truck. A simulation for a truck frontal crash to a rigid barrier using the model is performed with PAM-CRASH installed in super computer SP2. Full vehicle model is composed of 86467 shell elements, 165 beam elements and 98 bar elements, and 86769 nodes. The model uses four material model such as elastic, elastic-plastic(steel), rigid and elastic-plastic(rubber) material model which are in PAM-CRASH. Frame and suspension system are modeled with 28774 shell elements and 31412 nodes. Cab is modeled with 34680 shell elements and 57 beam elements, and 36254 nodes. Bumper is modeled with 2262 shell elements, and 2508 nodes. Axle, steering shaft, etc are modeled using beam or bar elements. Mounting parts are modeled using rigid bodies. Bodies are interconnected using nodal constrains or joint options. To verify the developed model, frontal crash test with 30mph velocity to a rigid barrier is carried out. In the crash test, vehicle pulse at lower part of b-pillar is measured, and deformed shapes of frame and driver seat area are photographed. Those measured vehicle pulse and photographed pictures are compared those from the simulation to verify the developed finite element model.

• Journal of Welding and Joining
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• v.11 no.3
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• pp.22-33
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• 1993

Arc sensor is indispensable to arc welding robot systems for compensating the joint misalignment such as mismatch of the workpiece, ill-conditioned positioner and thermal deformation during welding. Furthermore, the amount of these mismatches cannot be preivously expected, and changes from time to time. There are many kinds of seam trackers for correcting the welding path of the robot, where non-contact type sensors arc prevalently used in arc welding robot systems. In this study, an arc sensor was developed for GMA and FCA welding robot system. Since the arc sensor uses the arc characteristics during welding, the operating principle of the arc sensor must be adjusted according to the welding condition. Especially in GMA welding with the $CO_{2}$ shielding gas, the welding arc is not stable because of the short circuit and non-axial globular transfer mode of the molten droplet. In this study, the 2nd order least square curve fitting algorithm was adopted and the applicability of this algorithm was investigated for robot welding systems. For easy usage of the arc sensor, the operating parameters for arc sensor were limited to eight which can be easily determined by the operator.

• New & Renewable Energy
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• v.3 no.4
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• pp.104-113
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• 2007

교토의정서(Kyoto Protocol)의 발효로 전 세계적으로 에너지절약형 산업구조로의 전환 및 신재생에너지 개발 등의 온실가스 감축을 위한 노력이 활발하게 진행되고 있으며, 우리나라 또한 온실가스 저감을 피할 수 없게 되었다. 특히 선진국(Annex I)의 구속력 있는 감축목표를 규정하고 있는 교토의정서의 의무이행에 유연성을 부가하기 위해 교토메카니즘이 채택되었다. 교토 메카니즘은 CDM(Clean Development Mechanism), JI(Joint Implementation), ET(Emission Trading)로 이루어져 있으며, 이 가운데 CDM 사업은 선진국(Annex I)과 개발도상국 non-Annex I)간 공동 협력 사업으로 non-Annex I 국가인 우리나라가 참여할 수 있기 때문에 국내 기업 및 정부의 관심이 높아지고 있다. 이러한 CDM 사업을 수행하기 위해서는 적용 가능한 CDM 사업 방법론이 필요하며, 방법론이 없을 경우 CDM 사업 방법론을 개발하여야 한다. CDM사업 방법론에는 레이스라인, 추가성, 배출 감축량, 모니터링 등에 대한 구체적인 방법이 제시되어야 하고 사업 수행자는 사업의 타당성 확인 및 검증을 위해 방법론을 정확히 이해해야 한다. 따라서 본 CDM사업 방법론 연구를 통해 CDM사업 수행 및 방법론 개발을 위한 주요 항목의 이해를 돕고 국내 CDM 사업의 활성화를 도모하고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.5
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• pp.420-426
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• 2001

In this paper, we introduce a case study of developing a miniature humanoid robot that has 16 degrees of freedom and is able to perform statically stable walking. The developed humanoid robot is 37cm tall and weighs 1,200g. RC servo motors are used as actuators. The robot can walk forward and turn to any direction on an even surface. It equipped with a small digital camera, so it can transmit vision data to a remote host computer via wireless modem. The robot can be operated in two modes: One is a remote-controlled mode, in which the robot behaves according to the command given by a human operator through the user-interface program running on a remote host computer, the other is a stand-alone mode, in which the robot behaves autonomously according the pre-programmed strategy. The user-interface program also contains a robot graphic simulator that is used to produce and verify the robot\`s gait motion. In our walking algorithm, the ankle joint is mainly used for balancing the robot. The experimental results shows that the developed robot can perform statically stable walking on an even surface.

• Tribology and Lubricants
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• v.26 no.1
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• pp.44-51
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• 2010

A miniature shear testing machine was designed and developed, adopting a piezoelectric actuator with mechanical advantage using 4 levers in order to investigate shear behavior of a small solder ball. The final output displacement was initially expected to be 2.88 mm without load resistance, considering the lever ratio of 24 and the piezo displacement of 0.12 mm with an exciting voltage of 10 V. However, the final plunger displacement ${\Delta}{\upsilon}$ can be expected as ${\Delta}{\upsilon}=2.88-3.04{\times}10^{-4}F$ as a function of piezoelectric force F due to the stiffness of various levers and connectors and piezo actuator. The shear behavior of lead-free solder ball in diameter of $760{\mu}m$ was successfully investigated in a speed range of 2 mm/s~0.0035 mm/s using this designed device.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.87-98
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• 1999

This study is concentrated on the development of real-time estimation model and vision control method as well as the experimental test. The proposed method permits a kind of adaptability not otherwise available in that the relationship between the camera-space location of manipulable visual cues and the vector of manipulator joint coordinates is estimate in real time. This is done based on a estimation model ta\hat generalizes known manipulator kinematics to accommodate unknown relative camera position and orientation as well as uncertainty of manipulator. This vision control method is roboust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the manipulator, and correct knowledge of position and orientation of CCD camera with respect to the manipulator base. Finally, evidence of the ability of real-time vision control method for manipulator's position control is provided by performing the thin-rod placement in space with 2 cues test model which is completed without a prior knowledge of camera or manipulator positions. This feature opens the door to a range of applications of manipulation, including a mobile manipulator with stationary cameras tracking and providing information for control of the manipulator event.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.2
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• pp.95-99
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• 2011

The development of different entities of soft tissue sarcoma in one patient is rare. It usually affects head and neck or abdominal region, whereas those affecting the extremities are much rarer. We describe a patient with double primary presentation of liposarcoma and Ewing's sarcoma in extremity. This case implies that sarcoma patients are at increased risk of a second malignancy, and this implies a need to search for occult tumors during follow up.

• Journal of the Korea Computer Industry Society
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• v.2 no.8
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• pp.1133-1138
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• 2001

In this paper, we implemented that MMT(Multimedia Terminal) demonstrates spot news, weather forecast, sports news and cultural news employed CDMA mobile communication networks. The MMT displays mobile pictures/joint pictures/on screen ad and to make known Bus stop or Mobile stations. The MMT gives driver's and passenger's safety and valuable information for one's use GPS satellites. We verified to make real time mobile picture transfer use of CDMA2000 1×(IS-95C) network and development the scheduler control each module. This system tested on vehicle that train and bus. MMT was implemented high reliability and stability by the embedded system. The mobile terminal shows reliable data transfer rate about 74Kbps on IS-95C.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.1
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• pp.22-27
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• 2010

Many people in these days participate in running as leisure due to urbanization and socio-economic development. Running is a simple exercise but it can induce its own specific injury pattern because of its repetitive motion. Most runners' injury is caused by chronic overuse syndrome rather than acute trauma. And common accompanying injury in running are anterior knee pain syndrome, Iliotibial band syndrome, stress fracture, plantar fasciitis, Achilles tendinitis, posterior tibial tendon syndrome. Most common area of runners' injury is knee joint. Therefore the authors reviewed the recent literatures and described the classification, etiology, prevention, rehabilitation in this article.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1551-1564
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• 2016

The high penetration level of inverter-based distributed generation (DG) power plants is challenging the low-voltage ride-through requirements, especially under unbalanced voltage sags. Recently, a flexible injection of both positive- (PS) and negative-sequence (NS) reactive currents has been suggested for the next generation of grid codes. This can enhance the ancillary services for voltage support at the point of common coupling (PCC). In light of this, considering distant grid faults that occur in a mainly inductive grid, this paper proposes a complete voltage support control scheme for the interface inverters of medium or high-rated DG power plants. The first contribution is the development of a reactive current reference generator combining PS and NS, with a feature to increase the PS voltage and simultaneously decrease the NS voltage, to mitigate voltage imbalance. The second contribution is the design of a voltage support control loop with two flexible PCC voltage set points, which can ensure continuous operation within the limits required in grid codes. In addition, a current saturation strategy is also considered for deep voltage sags to avoid overcurrent protection. Finally, simulation and experimental results are presented to validate the effectiveness of the proposed control scheme.