• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.20 no.3
• /
• pp.207-213
• /
• 1998

Purpose : This study attempted to relate the incidence of fractures at the mandibular angle with the presence and state of eruption of lower third molars, and to find out the real risk factors for angle fractures in the states of lower third molars. Materials and Methods : Medical records and radiographs of 395 patients with mandibular fractures were retrospectively reviewed. The presence and states of third molars were assessed for each patients and related to the occurrence of angle and other mandibular fractures. Results : Of 395 patients with mandibular fractures, 142 had angle fractures. The incidence of angle fractures was found to be significantly greater when partial erupted lower third molars were present and it had a definite role for risk factors for angle fractures. But there were no clear relationship between the incidence of angle fracrtures and states of without, fully erupted lower third molars. Furthermore, the states of patial and unerupted lower third molar had an effect on bony segment displacement. Conclusions : This study provides clinical evidence to suggest that patial erupted third molar teeth weaken the mandibular angle both quantitatively and qualitatively.

• The Korean Journal of Applied Statistics
• /
• v.34 no.6
• /
• pp.937-944
• /
• 2021

The problem of selecting variables is addressed in partial linear regression. Model selection for partial linear models is not easy since it involves nonparametric estimation such as smoothing parameter selection and estimation for linear explanatory variables. In this work, several approaches for variable selection are proposed using a fast forward selection algorithm, least angle regression (LARS). The proposed procedures use t-test, all possible regressions comparisons or stepwise selection process with variables selected by LARS. An example based on real data and a simulation study on the performance of the suggested procedures are presented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.395-398
• /
• 2000

Reactive radio frequency (RF)magnetron sputter with incident angle has been used to deposit AlN thin film on a crystalline Si substrate. (002)Preferred orientation of AlN thin film has been obtained at low sputtering pressure. Also it has been shown that depostion rate of AIN thin film is affected by fraction Ar and $N_2$ partial pressure. But substrate temperature didn't affect depostion rate of AIN thin film . As sputtering pressure increased preferred orientation degraded. The internal stress changed from tensile stress to compressive stress as fraction of $N_2$ partial pressure increased. At low nitrogen partial pressure cermet$^{[1]}$ AIN thin film is obtained.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.5
• /
• pp.213-221
• /
• 2002

In order to improve the reliability of XLPE cables, it is necessary to find the useful diagnostic parameter according to long term aging. This paper described the change of partial discharge(PD) phase Properties of XLPE cable insulation with branch type electrical tree degradation. for long term aging. To understand the PD Properties with $\phi$ -q-n distributed shape of XLPE insulation, specimens were prepared by 22.9㎸ distribution cable and made in a type of block(16${\times}$16${\times}$3[mm]). Ogura needles having tip radius of l0${\mu}{\textrm}{m}$ were inserted into each block pieces. The measuring system was consisted of PD detector, digitizer for digital conversion, VXI system for signal processing. The PD properties of the specimens were measured from initiation of tree to breakdown and their characteristics were analyzed. We analyzed the relationship between electrical properties(PD Quantity, PD initiation angle, PD extinction angle, PD occurrence angle : (PD extinction angle - PD initiation angle)) and the normalized aging rate. We found PD parameter, PD initiation angle and occurrence angle, which are a useful diagnostic parameter in estimating the branch type electrical tree for XLPE insulation condition.

• Journal of the Society of Naval Architects of Korea
• /
• v.46 no.6
• /
• pp.569-577
• /
• 2009

As the scale factor of model propellers utilized in cavitation test is about 40, it is difficult to find out practical countermeasures against the small area erosions on the blade tip region throughout model erosion tests. In this study, a partial propeller blade model was used for the observation of cavitation pattern for the eroded propeller. A partial propeller blade model was manufactured from 0.7R to tip with expanded profile and with adjustable device of angle of attack. Reynold's number of a partial propeller blade model is 7 times larger than that of a model propeller. Also, anti-singing edge and application of countermeasures to partial propeller blade model which produced in large scale can be more practical than a model propeller. For the observation of cavitation at high Reynold's number, high speed cavitation tunnel was used. To find out the most severe erosive blade position during a revolution, cavitation observation tests were carried out at 5 blade angle positions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.132-135
• /
• 1999

In this work, two approaches were proposed for the recognition of partial discharge patterns. The first approach was neural network with backpropagation algorithm, and the second approach was angle calculation between two operator vectors. PD signal were detected using three electrode systems; IEC(b), needle-plane and CIGRE method II electrode system. Both of neural network and angle comparison method showed good recognition performance for the patte군 similar to the trained patterns. And the number of operators to be used had a great influence on the recognition performance to the untrained patterns.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.43 no.1
• /
• pp.46-48
• /
• 2017

A patient, who underwent partial masseter muscle resection and mandibular angle reduction at a plastic surgery clinic, visited this hospital with major complaints of trismus and dysesthesia. A secondary angle formation due to a wrong surgical method was observed via clinical and radiological examinations, and the patient complained of trismus due to the postoperative scars and muscular atrophy caused by the masseter muscle resection. The need for a masseter muscle resection in square jaw patients must be approached with caution. In addition, surgical techniques must be carefully selected in order to prevent complications, and obtain effective and satisfactory surgery results.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1382-1386
• /
• 2003

In this paper, we propose a controller for the position of a cart and the angle of a pendulum. To achieve both purposes simultaneously, we divide the system into the dominant subsystem and the dominated one after partial feedback linearization. The proposed controller is composed of a nonlinear controller stabilizing the dominant subsystem and a linear quadratic controller. Using the proposed controller, the controllable region is increased by the nonlinear control part and the control input minimized by the linear control part (LQR).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.2
• /
• pp.8-17
• /
• 2000

In this work, two approaches were proposed for the recognition of partial discharge patterns. The first approach was neural network with backpropagation algorithm, and the second approach was angle calculation between t재 operator vectors. PD signals were detected using three electrode systems; IEC(b), needle-plane and CIGRE method II electrode system. Both of neural network and angle comparison method showed good recognition performance for the patterns similar to the trained patterns. And the number of operators to be used had a great influence on the recognition performance to the untrained patterns.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.2
• /
• pp.36-43
• /
• 2011

The present study deals with numerical flow analysis to investigate the effect of sweep and lean on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for three different angles. The angles of sweep and lean are $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The results of the flow analysis showed that the efficiency is improved as the sweep angle is increased. However, a sweep angle of $5^{\circ}$ was less effective in comparison with the baseline model. The total pressure loss was reduced as the lean angle is increased, but the total to static efficiency was decreased.