• The korean journal of orthodontics
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• v.42 no.1
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• pp.39-46
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• 2012

Objective: We evaluated the detachment force, amount of deformation, fracture mode, and pull-out force of 3 different wires used for bonded lingual retainer fabrication. Methods: We tested 0.0215-inch five-stranded wire (PentaOne, Masel; group I), $0.016{\times}0.022$-inch dead-soft eight-braided wire (Bond-A-Braid, Reliance; group II), and 0.0195-inch dead-soft coaxial wire (Respond, Ormco; group III). To test detachment force, deformation, and fracture mode, we embedded 94 lower incisor teeth in acrylic blocks in pairs. Retainer wires were bonded to the teeth and vertically directed force was applied to the wire. To test pull-out force, wires were embedded in composite that was placed in a hole at the center of an acrylic block. Tensile force was applied along the long axis of the wire. Results: Detachment force and mode of fracture were not different between groups. Deformation was significantly higher in groups II and III than in group I (p < 0.001). Mean pull-out force was significantly higher for group I compared to groups II and III (p < 0.001). Conclusions: Detachment force and fracture mode were similar for all wires, but greater deformations were seen in dead-soft wires. Wire pull-out force was significantly higher for five-stranded coaxial wire than for the other wires tested. Five-stranded coaxial wires are suggested for use in bonded lingual retainers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.420-425
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• 2010

In the process of warm forging, billet is heated up to $800^{\circ}C$ and located in the upper part of die block impression. The scattered oxidized scale may cause workers burn and shortening of die life sticking to the die block impression. The separating materials sprayed in die block cause harmful dust, harmful mist, fume, and bad odor which contaminate workshop environment. The process is classified as one of the avoided jobs and make the planned output achievement difficult. Development of an elimination device to clear out the contaminating materials in the workshop and improvement of the unsatisfactory maintenance method to fix the abrasion of die block impression which delays the dead line, cost increases needs to be developed. In this research, I tried to solve the problems caused in warm forging of bronze pipe joint such as the billet heating process, die maintenance, and manufacturing cost through improvement of warming forging manufacturing method and die maintenance method and eliminating harmful gas which will make the workshop more environment friendly.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.475-487
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• 2003

This study developed an analysis model of estimating fatigue damage using the linear elastic fracture mechanics method. Stress history occurring to an element when a truck passed over a bridge was defined as block loading and crack closure theory explaining load interaction effect was applied. Stress range frequency analysis considering dead load stress and crack opening was done. Probability of stress range frequency distribution was applied and the probability distribution parameters were estimated. The Monte Carlo simulation of generating the probability various of distribution was performed. The probability distribution of failure block numbers was obtained. With this the fatigue reliability of an element not occurring in failure could be calculated. The failure block number divided by average daily truck traffic remains the life of a day. Fatigue reliability analysis model was carried out for the welding member of cross beam flange and vertical stiffener of steel box bridge using the proposed model. Consequently, a 3.8% difference was observed between the remaining life in the peak analysis method and in the proposed analysis model. The proposed analysis model considered crack closure phase and crack retard.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.11
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• pp.21-30
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• 1998

In this paper, a digital current control system using a FPGA(Field Programmable Gate Array) was implemented, and the system was applied to an induction motor widely used as an industrial driving machine. The FPGA designed by VHDL(VHSIC Hardware Description Language) consists of a PWM(Pulse Width Modulation) generation block, a PWM protection block, a speed measuring block, a watch dog timer block, an interrupt control block, a decoder logic block, a wait control block and digital input and output blocks respectively. Dedicated clock inputs on the FPGA were used for high-speed execution, and an up-down counter and a latch block were designed in parallel, in order that the triangle wave could be operated at 40 MHz clock. When triangle wave is compared with many registers respectively, gate delay occurs from excessive fan-outs. To reduce the delay, two triangle wave registers were implemented in parallel. Amplitude and frequency of the triangle wave, and dead time of PWM could be changed by software. This FPGA was synthesized by pASIC 2SpDE and Synplify-Lite synthesis tool of Quick Logic company. The final simulation for worst cases was successfully performed under a Verilog HDL simulation environment. And the FPGA programmed for an 84 pin PLCC package was applied to digital current control system for 3-phase induction motor. The digital current control system of the 3 phase induction motor was configured using the DSP(TMS320C31-40 MHz), FPGA, A/D converter and Hall CT etc., and experimental results showed the effectiveness of the digital current control system.

• Journal of Chest Surgery
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• v.28 no.1
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• pp.11-17
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• 1995

Fourty-three infants underwent intracardiac repairs within the first 12 months of life. Mean age was 7 months and mean weight was 6.7 kg. A quarter of them were below 5 kg. Overall mortality including complex anomalies was 17.9%. Thirty-four infants with a ventricular septal defect[VSD were treated. Three infants[8.8% died in the early postoperative period, but only one[3.7% of the infants without having associated lesions was dead. VSD was repaired either by the incision on the right atrium, pulmonary artery, or right ventricle. Postoperative right bundle branch block[RBBB occurrence were different according to the approach: 30.8 % in pulmonary arteriotomy, 37.5 % in atriotomy, and 42.8 % in ventriculotomy. Surgically induced heart block did not occur in any patient, but 10 had temporary arrhythmia, and 11 patients were under temporary pacing from one day to 4 days without any persisting rhythm disturbances. Pulmonary hypertension was present in 29 infants preoperatively, and seven of them developed postoperative elevation of the pressure. Infants complicated with pulmonary hypertensive crisis were managed successfully. Inotropics were necessary in 55.8 % of the infants and vasodilators in 37.2 %. Platelet transfusion were needed in 10 cases who required 272 ml in average, but one who died from sepsis consumed 5,370cc of platelets. And we discuss complications and causes of deaths.

• Journal of Communications and Networks
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• v.11 no.5
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• pp.455-463
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• 2009

We consider the challenges of finding good puncturing patterns for rate-compatible low-density parity-check code (LDPC) codes over additive white Gaussian noise (AWGN) channels. Puncturing is a scheme to obtain a series of higher rate codes from a lower rate mother code. It is widely used in channel coding but it causes performance is lost compared to non-punctured LDPC codes at the same rate. Previous work, considered the role of survived check nodes in puncturing patterns. Limitations, such as single survived check node assumption and simulation-based verification, were examined. This paper analyzes the performance according to the role of multiple survived check nodes and multiple dead check nodes. Based on these analyses, we propose new algorithm to find a good puncturing pattern for LDPC codes over AWGN channels.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.161-163
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• 2011

최근 몇 년사이 CCTV에 대한 활용도와 중요성이 대두되고 있으며, CCTV의 해상도 또한 SD급 CCTV에서 HD급 CCTV로 대부분 전환되고 있는 상황이다. HD급 CCTV는 고화질, 고해상도를 제공하는 장점을 갖지만, 많은 데이터 량으로 인해 실시간 처리가 어려운 문제점 또한 포함하고 있다. 또한 CCTV는 지능형 CCTV로의 기술적인 진보를 거듭하고 있으며, 대표적인 solution으로 증강현실(AR:Augmented Reality)을 꼽을 수 있다. 본 논문에서는 HD-CCTV의 최대 장점이라고 할 수 있는 실시간 영상에 선박의 정보(AIS : Automatic Identification System)을 결합하여 실시간으로 항만을 모니터링 하는 시스템을 구현하였다. 또한 750mm Zoom Lens를 탑재한 PanTilt 장비를 이용하여 선박을 targeting 하는 시스템 또한 구현하였다. 증강현실을 이용하여 실시간 영상과 선박 정보를 결합하였으며, 이를 구현하기 위해 perspective projection 방법을 통해 3차원 공간좌표계를 2차원으로 투영하였다. 실시간 처리를 위해 입력영상을 Block으로 분할하여 목적 좌표를 검색하였으며, 선박정보의 부드러운 이동을 위해 Dead Reckon 기법과 linear prediction 방법을 이용하여 선박 위치를 예측하였다. 마지막으로 삼각측량법에 기반하여 현재 PanTilt 장비를 목적된 장소로 이동시키는 시스템을 구현하였다.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.363-365
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• 2005

KHSR(Korean High Speed Railway) had achieved the maximum speed of 350 km/h last year. And then, we have concentrated to improve the reliability of the overall system, in particular, motor block of the locomotive. In this paper, simple technique for operating PWM converters under the voltage distortion is introduced. In addition, the electrical braking technique is also made to have the braking capability under the dead zone. Test results revealed the verification of the proposed techniques.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6A
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• pp.389-398
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• 2012

In this study, structural strain responses of the jacket-type Uldolmok tidal current power plant structure under severe tidal environments were measured and analyzed using long-term measurement system during construction and also operation. It was observed that there were significant changes in strain responses at the steps of jacket lifting, block loading, pile ejection and insertion. Strains due to dead loads and tidal loads were analyzed before and after removal of a jacket leg, and it was also found that the strains due to dead load were much significantly changed after jacket leg removal. From the measurement data during operation, it was found that strain responses were fluctuated with M2 and M4 tidal periods and also relatively short period of about 10 min due to the peculiar tidal characteristics in the Uldolmok strait. Finally, the neural network-based non-parametric estimation models were investigated to build up the signal-based structural damage monitoring system.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.77-86
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• 2016

This paper describes a dual-mode reference-less CDR(Clock Data Recovery) operating at full / half-rate and its operation algorithm. Proposed reference-less CDR consists of a frequency detector, a phase detector, a charge pump, a loop filter, a voltage controlled oscillator, and a digital block. The frequency and phase detectors operate at both full / half-rate for dual-mode operation and especially the frequency detector is capable of detecting the difference between data rate and clock frequency in the dead zone of general frequency detectors. Dual-mode reference-less CDR with the proposed algorithm can recover the data and clock within 1.2-1.3 us and operates reliably at both full-rate (2.7 Gb/s) and half-rate (5.4 Gb/s) with 0.5-UI input jitter.