• Journal of Korean Dental Science
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• v.16 no.1
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• pp.63-73
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• 2023

Purpose: Hyperdontia is a developmental disorder of the oral cavity. Mesiodens refers to the hyperdontia located between the maxillary central incisors. During the surgical procedure, the anesthetic method for pain control should be considered along with factors related to the surgery itself. The purpose of this study was to evaluate the effect of the impacted position of the mesiodens on the selection of sedation method and to suggest incisive foramen as a brief reference. Materials and Methods: This study included 126 patients who were scheduled for extraction of mesiodens. The selection criteria included patients with one palatally impacted inverted mesiodens accessible from the palatal gingival margin, and those with good cooperation potential in order to control for clinical information. Using cone beam computed tomography, vertical, horizontal, and palatal positional factors were measured, and the anesthetic method was determined by two examiners. The patients were grouped into vertical and horizontal groups based on the position of the incisive foramen. Data were statistically analyzed using the Mann-Whitney test, the chi-square test, and logistic regression analysis. Result: All positional factors differed between the outpatient and inpatient anesthetic groups. The vertical minimum distance from the alveolar ridge to the mesiodens (Va) and the minimum distance from the palatal surface to the crown tip of the mesiodens (Tc) were factors affecting the choice of anesthetic method. The distribution of the vertical and horizontal positional groups differed between the outpatient and inpatient anesthetic groups. Conclusion: The incisive foramen can be used as a brief reference to determine the appropriate anesthetic method. Referral for inpatient anesthesia may be a priority if they are in the V₂H₂ group with Va ≥5 mm, and Tc ≥6 mm, and outpatient sedation may be considered if they are in the V₁H₁ group with Va ≤1.5 mm, and Tc ≤2.5 mm.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.12-15
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• 1996

In this paper, a new shape control law is derived as a result of introducing the parametric curve representation. This control alw is based on the estimation of the curve parameters corresponding to the target joint positions and the target tip position. Estimating target curve parameters makes it possible to find, easily, a simple shape control law by the Lyapunov design method.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.215-219
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• 2003

In this paper, we generate a trajectory minimized the energy gait of a biped robot for walking a staircase using genetic algorithms and apply to the computed torque controller for the stable dynamic biped locomotion. In the saggital plane, a 6 degree of freedom biped robot that model consists of seven links is used. In order to minimize the total energy efficiency, the Real-Coded Genetic Algorithm (RCGA) is used. Operators of genetic algorithms are composed of a reproduction, crossover and mutation. In order to approximate the walking gait, the each joint angle is defined as a 4-th order polynomial of which coefficients are chromosomes. Constraints are divided into equality and inequality. Firstly, equality constraints consist of position conditions at the end of stride period and each joint angle and angular velocity condition for periodic walking. On the other hand, inequality constraints include the knee joint conditions, the zero moment point conditions for the x-direction and the tip conditions of swing leg during the period of a stride for walking a staircase.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1542-1546
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• 2003

Nanotechnology is an important challenge, for which nanoparticle manipulation plays an important role in the assembly of nano elements. In this study, the dynamic equation of system plant is established by van der Waals force, friction, capillary forces etc. To push nanoparticles, strain gauges are used as sensors to actuate an X-Y stage in an atomic force microscopy system. A strategy of pushing nanoparticles is developed based on sliding mode control. Moreover, afuzzy controller is responsible for compensating tip-particle contact loss according to feedback signals of a laser-detector system. According to position control result, experimental results of gold nanoparticle manipulation are presented.

• Smart Structures and Systems
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• v.20 no.4
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• pp.499-508
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• 2017

The ionic polymer-metal composite (IPMC) is an electroactive polymer material and has a promising potential as actuators for propulsion and locomotion in underwater systems. In this paper a physics based model is used to analyse the actuation dynamics of the IPMC propulsor. Moreover, proportional-integral (PI) controller is used for position control of the tip displacement of IPMC propulsor. PI parameter tuning is performed using particle swarm optimization (PSO) algorithm. Several performance indices have been used as an objective function to optimize the error of the system. Finally, the best tuning method is found out by comparing the results under various performance indices.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.2
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• pp.19-24
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• 2016

Positional stability analysis based on aerodynamic forces and induced moments of formation flight using two small aircraft models is presented. The aerodynamic force and moments of the trailing aircraft are analyzed in the aspect of flight stability. The induced moments with the change of local flow direction by wing-tip vortex from the leading aircraft can affect the flight positional stability of aircraft in closed formation flight. Aerodynamic forces and moments of trailing aircraft model are measured by 6-component internal balance at the 49 locations with vertical and lateral space between two aircraft models. Results are shown that the positional stability of trailing aircraft in formation flight can be analyzed by positional stability derivatives with vertical and lateral space. It is concluded that flying positions can be important factors for aircraft position stability due to induced aerodynamic force and moments with vertical and lateral spacing by the variation of flow pattern from the leading aircraft in formation flight.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1594-1603
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• 2002

In this paper, when the initial propagation angle of a branched crack is calculated from the maximum tangential stress criterion (MTSC) and the minimum strain energy density criterion (MSEDC), it is essential that you use stress components in which higher order terms are considered and stress components at the position in a distance 0.005㎜ from the crack tip (=r). When an interfacial crack propagates along the interface at a constant velocity, the initial propagation angles of the branched crack are similar. to the mode mixities (phase angle) and the theoretical values obtained from MTSC and MSEDC. The initial propagation angle of the branched crack depends considerably on the stress intensity factor K$_2$.

• Journal of Korean Neurosurgical Society
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• v.51 no.3
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• pp.182-186
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• 2012

In conventional percutaneous disc surgery, introducing instruments into disc space starts by inserting a guide needle into the triangular working zone. However, landing the guide needle tip on the annular window is a challenging step in endoscopic discectomy. Surgeons tend to repeat the needling procedure to reach an optimal position on the annular target. Obturator guiding technique is a modification of standard endoscopic lumbar discectomy, in which, obturator is used to access triangular working zone instead of a guide needle. Obturator guiding technique provides more vivid feedback and easy manipulation. This technique decreases the steps of inserting instruments and takes safer route from the peritoneum.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.891-896
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• 2007

This paper contained the flight test calibration for the airspeed indicator and the altimeter of the light airplane ChangGong-91, which is the first type certified aircraft from Korean Ministry of Construction and Transportation, as a part of the flight test validation. The flight test for airspeed position error calibration was performed using tower fly by method in order to calibrate swivel head testboom which is attached to the right wing tip of the airplane, and using system to system method for airspeed indicator. The altimeter calibration was calculated using flight test data for airspeed calibration. The flight test was conducted at the basis of the 'Korean Airworthiness Standard' regulation of Korean Ministry of Construction and Transportation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.218-222
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• 1993

A sliding mode controller associated with the moving sliding surface is formulate for the tip position control of a single-link flexible manipulator. After establishing the plant model which characterizes a noncollocated control system, a discontinuous control law is then constructed by restricting that velocity state variables are not available from direct sensor measurements. Using the proposed control law favorable system responses are accomplished through shortening the reaching phase without increasing maximum control torque. Furthermore, a low sensitiveness to extraneous disturbance is obtained. Computer simulations are undertaken in order to demonstrate these superior control performance characteristics to be accrued from the proposed methodology.