• Computers and Concrete
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• v.1 no.3
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• pp.249-260
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• 2004

The stress transmission mechanism in pretensioned concrete beams, though very interesting from an economical point of view, is very complex, integrating various phenomenons such as sliding, bond, bursting. For long the complexity of this mechanism has led engineers to provide a massive rectangular anchorage zone at each end of the beam. The necessity of using such a concrete reinforcement is certainly unquestionable in post-tensioned beams. However in pretensioned elements the stresses induced in concrete in the anchorage zone are smaller than in post-tensioned elements. In this article the stress field in the end zone is calculated numerically and from this analysis the possible reduction of the cross-section of the anchorage block is examined.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.71-76
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• 2006

In this paper, a long gauge Fiber Bragg Grating (FBG) sensor system is described and long gauge FBGs are well, suited for measuring the upper parts of the bridge piers under the extremely severe movement conditions. In the experiments, we used more than 30m long FBG sensors to measure the movement of top part of the bridge piers which are separated from the main bridge by cutting the decks. With the actuator, the deck and girders were pushed and released. We checked the movement of the top of the pier while releasing the pressure of the actuator with the long gauge fiber sensor. In order to measure the movement of the upper part of the pier, the reference point must be outside of the pier. Using the optical fiber sensors, one end of the sensor is attached to the top of the pier and the other end is attached to the bottom of the next pier. The fiber sensors showed good response to the release loading and we could calculate the movement of the top part of the pear.

• Journal of the Korean Society for Railway
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• v.1 no.1 s.1
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• pp.1-9
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• 1998

Described in this paper is the result of a study on collision analysis of TGV-K using 1-dimensional model for crashworthy design. Crashworthy design of the front end is very important because majority of the impact energy (more than 70%) is absorbed by the crush of the front end when the train is collided with an obstacle like a tank lorry. Guideline for the crashworthy design can be described from the collision analysis of the whole train using a 1-dimensional model. Since the headstock of TGV-K is not designed in a crashworthy point of view, a conceptual design of the headstock to improve crashworthiness is suggested and evaluated using 1-dimensional collision analysis. The suggested design, which adopts an energy absorber and a crashworthy headstock, shows a good behaviour on the accident scenario of SNCF (collision at 110 km/h against a movable rigid mass of 15 ton).

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.26-34
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• 1998

In this paper, a force control algorithm for edge following task is suggested. Through the contact state modeling between rigid part and end-effector of robot, contact force and contact angle that are essencial parameters to build the control strategies for following movement of end-effector are derived. From these two parameters, we discriminate the every contact state into 8 cases and calculate the new moving position and direction simply. For the experiment. RX90 robot from Staubli with robot language V$^{+}$ is applied and F/T sensor is attached to the wrist of robot with RCC. Finally, 3 edge following experiments including the following of corner point are executed with successful results.s.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.4
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• pp.75-80
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• 2001

An error analysis is very important to estimate performance of a precision machine. This study proposes an error analysis for a new parallel device, a cubic parallel device. The cubic parallel manipulator has error sources including upper and lower universal joint errors due to the directional changes in the link and actuation errors. The maximum errors of the end effector are affected by the axial direction changes of each links and the clearances of the universal joints when the parallel manipulator is moving along a path. It is found that the changes of errors mostly occur at the positions where the directions of exerting link forces shift. The error analysis is based on an error model formed from the relation between the universal point errors and the end-effector accuracy. The analysis method can be also used in predicting the accuracy of other parallel devices.

• Journal of Chest Surgery
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• v.27 no.4
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• pp.324-327
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• 1994

Resection and reconstruction of distal trachea or carina have posed tremendous technical challenges for surgeons. Successful outcome depends on thorough preoperative evaluation, careful anesthetic management,strict attention of surgical technique and postoperative care. We report a successful case of revision of tracheal stenosis using femoro-femoral bypass on a 13~year-old boy. The patient complained severe dyspnea about I month following right sleeve pneumonectomy. Preoperative CT scan and intraoperative bronchoscopy showed pin-point tracheal stenosis at a tracheo-bronchial anastomosis site about 1.2cm in length.At operation the lesion was severely adhesed and the lumen was nearly obstructed. The stenotic segment was resected and direct end-to-end anastomosis was done under femoro-femoral bypass for adequate oxygenation. The patient was discharged at postop. 16 days without specific complications and has continued to do well.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.220-228
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• 1995

An optimized 4-stage 12-bit pipelined CMOS analog-to-digital converter (ADC) architecture is proposed to obtain high linearity and high yield. The ADC based on a multiplying digital-to-analog converter (MDAC) selectively employs a binary-weighted-capacitor (BWC) array in the front-end stage and a unit-capacitor (UC) array in the back-end stages to improve integral nonlinearity (INL) and differential nonlinearity (DNL) simultaneously whil maintaining high yield. A digital-domain nonlinear error calibration technique is applied in the first stage of the ADC to improve its accuracy to 12-bit level. The largest DNL error in the mid-point code of the ADC is reduced by avoiding a code-error symmetry observed in a conventional digitally calibrated ADC is reduced by avoiding a code-error symmetry observed in a conventional digitally calibrated ADC is simulated to prove the effectiveness of the proposed ADC architecture.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.887-892
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• 2003

A front-end cooling fan is designed and tested in the present study. The design technique is developed using the one-dimensional inviscid flow through the fan blade, the empirical equations, and the experimental correlations. Design data for the blade can be obtained for a given flow rate and a pressure rise. A parabolic function is used to generate a sweep of the fan. Characteristics of the blade geometry are discussed between the huh and the tip. The fan is tested in the fan test unit. The measured volume flow rate at the operating point is in good agreement with that of the design specifications. Sound pressure levels of the noise are predicted with the Ffowcs Williams-Hawkings equations. Calculation results of the sound pressure level(SPL) 1m away from the fan are obtained and cpmpared with the measured data.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.209-212
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• 2002

LIM have mainly different point considering rotary induction motor, that is end effect. In this paper described that, end effect, adding to the rotary induction motor, They can be designed because of affects magnetizing inductance and series resistance in the d-axis circuit. After LIM modeling, using SVPWM, apply to vector control this model. We can verify feasibility of field onented control technology can control speed by simulation.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.279-290
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• 1998

The diagnosis of canine diabetes mellitus is generally made by measuring serum fructosamine levels. The Rosental's end points Tas and El Din's kinetic, and Johnson and colleagues'kinetic techiniques were compared for the measuring serum fructosamine levels. In the Rosental's end point methods within-run and between-run coefficient of variability (CV) were 2.4-3.5% and 6.8-8.5%, respectively, and in the Tas and El Din's kinetic method, within-run and between-run CV were 1.3-3.0% and 3.4-3.9%, respectively. In the Johnson and colleagues'kinetic methods within-run and between-run CV were 0-1.8% and 3.1-6.8%1 ruts- pectively. Hyperlipidemia induced by oral administration of 3 ml of corn oil per kilogram body weight did not affect serum fructosamine concentration significantly in the Johnson and colleagues' kinetic method Johnson and colleagues'kinetic method is most reliable and consistant on the basis of comparison study.