• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.1
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• pp.60-72
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• 1995

Temporomandibular joint ankylosis is the movemental obstacle of mandible which depend on proliferation of bony or fibrous tissue in temporomandibular joint structure by various causes. In order to treat this, various surgical methods have been performed, but no operative methods have been produced consistently successful results. This research has been performed to the patients who had been operated due to temporomandibular joint ankylosis by studying classification, cause, onset, duration, anesthesia and treatment method, symptom, change of mouth opening, complication through medical record, X-ray, follow-up for being a help to proper selection of treatment method and evaluation of prognosis. The author obtained the following results by analyzing 44 cases among patients who had been operated due to temporomandibular joint ankylosis during 8 year hospitalization from 1986 to 1993 in Dept. of Oral & Maxillofacial Surgery of Seoul National University Hospital. 1. The occurrence was in the order of below 10, 20's, 10's, 30's. The average of occurrence was 12.95. Illness period was 50.0% within 10 years and 50% beyond 10 years. The average period of illness was 13.33 years. 2. Trauma occupied 54.5% of causes and inflammation occupied 45.5%. Men had more occurrences due to trauma and there was no difference in case of inflammation. 3. In nasotracheal intubations for general anesthesia, the cases of using fiberoptic laryngoscope occupied 40.9%, direct or blind nasotracheal intubation occupied 40.9% and the cases of using tracheostomy occupied 18.2%. 4. In operative approaching methods, submandibular & preauricular approach were mainly applied, and in operative methods, high condylectomy(Group I) occupied 11.4%, arthroplasty without interpositional material following condylectomy or gap ostectomy(Group II) occupied 11.4%, with interpositional material following high condylectomy (Group III) occupied 40.9%, and using condylar reconstruction following condylectomy or gap ostectomy(Group IV) occupied 36.6%. 5. In change of mouth opening reformed after surgery, Group III showed the best result of average 23.5mm, Group IV showed 16.3mm, Group I showed 14.9mm and Group II showed 10.2mm of reformation. Summarizing the results as written above, it is considered that early treatment is important as soon as possible in Temporomandibular joint ankylosis. It is recommended in surgical method what can lead to postoperative early movement maintaining anatomaical & functional form, and then the development of various surgical methods will be requested.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.188-193
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• 1993

In widening of existing bridges, construction joints between old new parts of concrete slabs are subjected to repeated traffic loads during placing and curing of concrete. Therefore, the main focus of this paper is given to examine several construction methods of bridge widening. As a result, the occurrence of cracks in vibrating specimen is faster than non-vibrating one, but the difference between flexural strength and ultimate moment was negligible. Also, it shows the same result in other construction method, say direct and non-shrinkage joint specimen.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.433-437
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• 1988

Direct measurement of the relative position between the end effector of robot and moving objects reduces difficulties caused by the joint encoder reading and transformation. For those purpose, the on-line sensing method using PSD sensor was developed in this paper. The sensor was calibrated on the precision table. Then, the relative position of a moving objects on the conveyor was measured while the robot was tracking the one.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.741-746
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• 2004

We propose a new technique to the design and real-time implementation of an adaptive controller for robotic manipulator based on digital signal processors in this paper. The Texas Instruments DSPs(TMS320C80) chips are used in implementing real-time adaptive control algorithms to provide enhanced motion control performance for dual-arm robotic manipulators. In the proposed scheme, adaptation laws are derived from model reference adaptive control principle based on the improved direct Lyapunov method. The proposed adaptive controller consists of an adaptive feed-forward and feedback controller and time-varying auxiliary controller elements. The proposed control scheme is simple in structure, fast in computation, and suitable for real-time control. Moreover, this scheme does not require any accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the proposed adaptive controller is illustrated by simulation and experimental results for a dual arm robot consisting of two 4-d.o.f. robots at the joint space and cartesian space.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.47-51
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• 1996

In this paper, we propose a method for compliance control of a SCARA type 2-freedom direct drive(DD) manipulator. Each joint of the manipulator is driven by a travelling ultrasonic motor(USM). The travelling USM has good some characteristics over conventional servo motors such as compact size, light weight, silent motion, high torque and high speed response. By controlling the elasticity and viscosity of robot joints, a robot can work in compliance with external environment. we control the elastic coefficient and the viscous coefficient of joint by adjusting the phase difference of the motor power. And we contemplate transient response of USM with adjusting the elastic coefficient and the viscous coefficient. To use the result, we can control the robot to reach its goal with compliance motion. It remains for further research to develop the impedance control of USM.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.938-948
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• 2001

In this paper, we present an exoskeletal haptic device named SKK Hand Master. This device is directly driven linkages actuated with small ultrasonic motors. By adopting ultrasonic motors that have advantageous features useful for cybernetic actuators, a compact haptic device containing whole driving packages can be established without additional power transmissions such as tendons. Methods for measuring joint postures and joint torques are developed and a new control strategy called PWM/PS is proposed to overcome intrinsic disadvantages such as hysteresis. Issues regarding design and construction of the device are addressed and several results of experiments for the evaluations of performance are included.

• The Journal of Engineering Geology
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• v.3 no.1
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• pp.1-20
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• 1993

In this study, laboratory direct shear tests on 37 core specimens of gneiss were performed to examine the characteristics of shear behavior on fractures by using a portable direct shear box. The multi-stage shear testing method was used and normal stress applied to specimens ranges from 5.60 to $25.67kg/\textrm{cm}^2$. On the basis of test results, the empirical equations for the shear strength on fractures were suggested. The methanical parameters that can influence the shear behavior were derived and compared between each parameter. The values of shear stiffness have a trend showing rapid increase with the increase of normal stress and joint roughness coeffident, and the average value of secant shear stiffness for all specimens is about $110.68kg/\textrm{cm}^3$ under the range of normal stress applied in this test In addition, the relationship between the length of specimen and shear stiffness is inversely correlated due to the size effect. Therefore, even the specimens with the same joint roughness coeffident show the trend of decreasing shear stiffness in case of the specimens being the longer length.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.6 s.177
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• pp.1633-1642
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• 2000

Like many other mechanical dynamic systems, flexible manipulator systems experience stiction or sticking friction, which may cause input-dependent instabilities. Manipulator performance can be enha nced by identifying friction but it is hard and expensive to measure friction by direct and precise sensing of contact displacements and forces. This study addresses the problem of identifying flexible manipulator joint friction. A dynamic model of a two-link flexible manipulator based upon finite element and Lagrange's method is constructed. The dynamic model includes the effects of joint compliances and actuator dynamics. Friction is also incorporated in the dynamic model to account for stick-slip at the joints. Next, the friction parameters are to be determined. The identification problem is posed as an optimization problem to be solved using nonlinear programming methods. A genetic algorithm is used to increase the convergence rate and the chances of finding the global optimum. The identified friction parameters are experimentally verified and it is expected that the identification technique is applicable to a system parameter identification problem associated with a wide class of nonlinear systems.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.67-73
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• 1988

This study was performed to clarify the mechanism of clicking sound and locking on temporomandibular joint and to determine the radiographic findings of them by using computed tomogram. Through the preliminary study with cadavers, the proper scanning condition and the correlatonship between the anatomy of cadaver and computed tomogram had been determined. The subjects were consisted of 10 controls and 16 patients having clicking sound or locking on temporomandibular joint. By using Hitachi-W500 as computed tomographic device, direct axial views and sagittal views reformed according to the changes in window setting and using the non-linear fraction were taken and analyzed by visual method and measuring the attenuation numbers. The obtained results were as follows: 1. The density of the anterior band of meniscus showed isodense to the surrounding muscles in normal. 2. In patient group, affected side showed increased radiopaque area anterior to condyle and underneath articular eminence as the feature of anteriorly displaced meniscus on axial and sagittal views. 3. In patient group, the condyle was rotated postero-laterally in affected side. 4. Non-linear fraction highlightened the feature of anteriorly displaced meniscus.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1400-1405
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• 2008

Execute surface of the earth geological survey for stability analysis of stealing cutting sides and investigated wide area nature of soil structure. Inflected DIPS that measure discontinuity's direction that develop to slope and is slope stability a wide use program for Stereographic Projection Method analysis that utilize geometrical correlation of stealing four sides and discontinuity surface. It is principle that angle of internal friction that is basis element of stability estimation applies direct shear test result on joint side, Examination is impossible by case execution, suppose by 30 angles that apply more conservatively in base rock slope sides usually and achieved analysis. When analyze, consider discontinuity's various adult that develop in research slope, after conduct first each discontinuity different assay falling into fault, joint, executed stability estimation which synthesize whole discontinuity data. When ailment element is recognized as analysis result, wished to present stability countermeasure way of most suitable to take into account of execution, stability, economic performance.