• The Journal of Korean Academy of Prosthodontics
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• v.59 no.2
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• pp.173-180
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• 2021

Purpose: The purpose of this study was to evaluate the retentive characteristics of the additional attachments used with implant bar attachment under repeated insertion/removal cycles. Materials and methods: The newly developed attachment and the commercially available attachment were investigated: ADD-Lock (AL), Locator blue (LB). Two fixtures were placed parallel to each other on the custom lower mounting, and patrix of each attachment was fixed to the fixture. Also, the matrix of each attachment was placed on the opposing upper mounting. A universal testing machine was used to measure the retentive force during initial, 100, 250, 500, 1000, 2000, and 2500 repeated insertion/removal cycles. Wear and deformation of the attachment s were observed by scanning electron microscopy (SEM). Mann-Whitney U test (α=.05) and wilcoxon signed-rank test (α=.05) were performed to compare retentive force between each group and before and after 2500 repeated insertion/removal cycles. Results: In terms of initial retentive force and retentive force after 2500 repeated insertion/removal cycles, the AL group (15.24 ± 1.46 N and 9.74 ± 1.16 N) showed significantly smaller values than the LB group (43.53 ± 12.39 N and 22.99 ± 4.77 N) (P<.05). Also, in the loss of retentive force, the AL group (5.50 ± 1.08 N, 36.08%) showed a smaller value than the LB group (20.54 ± 11.89 N, 47.19%) (P<.05). Based on SEM analysis, The AL group showed noticeable wear and deformation in the patrix and the LB group in the matrix. Conclusion: Locator showed a higher initial retentive force than newly developed attachment, while the loss of retentive force was also higher. Both additional attachments are considered to have sufficient retentive force after repeated insertion/removal cycles.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.679-682
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• 1998

This paper presents the VLSI implementation of RS(reed-solomon) decoder using the Modified Euclidean Algorithm(hereafter MEA) for DVD(Digital Versatile Disc) and CD(Compact Disc). The decoder has a capability of correcting 8-error or 16-erasure for DVD and 2-error or 4-erasure for CD. The technique of polynomial evaluation is introduced to realize syndrome calculation and a polynomial expansion circuit is developed to calculate the Forney syndrome polynomial and the erasure locator polynomial. Due to the property of our system with buffer memory, the MEA architecture can have a recursive structure which the number of basic operating cells can be reduced to one. We also proposed five criteria to determine an uncorrectable codeword in using the MEA. The overall architecture is a simple and regular and has a 4-stage pipelined structure.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.91.2-91.2
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• 2013

The Korean Solar Radio Burst Locator (KSRBL) is a solar radio spectrograph observing the frequency range between 0.245-18 GHz with the capability of locating the wideband gyrosynchrotron bursts. Its calibration process consists of antenna calibration, flux calibration, and demodulation. Antenna calibration is to determine the position, the width, and the peak value of the beam, flux calibration is to determine the conversion factor between the measured unit to the Solar Flux Unit (SFU), and demodulation is to determine the burst position and remove the modulation pattern. We introduce the current calibration software and some information that potential users may concern.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.74_76
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• 2009

This paper presents a discrete wavelet analysis based algorithm to address the fault impedance calculation under transient state in radial power distribution networks. The fault impedances have been derived under different fault conditions. Furthermore, a recursive fault distance estimation method is proposed utilizing the measured fault impedance and power line parameters. The proposed scheme can resolve the errors caused by the non-homogeneous power lines, the presence of lateral loads since, the fault impedance will always be updated with the recursive form. For the verification of the proposed scheme, a filed test has been peformed with varying fault resistances in the 22.9(kV) radial system. Power meters and fault locators were installed at the substation. It was figured out that the performance of the discrete wavelet and the recursive scheme are very good even for high fault resistance condition.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.185-189
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• 2001

In order to prevent the production defects the optimum design of product, jig and fixture putting in the field is very significant manufacturing method. Drilling Jig is the device according to industrial demand for multi manufacturing products on the growing at alarming rate. In the field of design and making for machine tool working, welding, assembling with jig and fixture for mass production is a specific division. They require analysis of many kinds of important factors, theory and practice of machine tool operating process and jig & fixture structure, machining condition for tool making, tool materials, heat treatment of jig & fixture components, know-how and so on. In this study we designed and constructed a drilling jig of mass production and performed tryout under the Auto CAD, Auto Lisp database, that we made by database, and window environment. Especially this study is reveals with the analysis of part drawing, jig planning, jig design etc, and then the result of drill jig's making try out.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.32.2-32.2
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• 2008

A major solar radio burst can disturb many kinds of radio instruments, including cellular phone, GPS, and radar. Korea Astronomy and Space Science Institute (KASI) is developing Korean Solar Radio Burst Locator (KSRBL) in collaboration with New Jersey Institute of Technology. KSRBL is a single dish radio spectrograph, which records the spectra of microwave (0.5 - 18 GHz) bursts with 1 MHz spectral resolution and 1 s time cadence, and locates their positions on the solar disk within 2 arcmin. Hardware manufacturing is almost completed including 4-channel digitizer/FPGA. The system is currently installed at Owens Valley Radio Observatory (OVRO), and test of the operation is in progress. It will be installed at KASI in 2009. We report current status and test results of KSRBL.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.61-63
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• 2003

인터넷 기반의 컴퓨팅 환경이 발전함에 따라 자원과 정보의 공유를 위한 그리드 컴퓨팅이 나타나게 되었다. 그리드 컴퓨팅에서는 그리드 응용 수행시 프로그램과 데이터간의 위치가 다르고 분산되어 있는 경우가 많다. 현재 그리드 미들웨어 시장 표준인 글로버스 둘킷(Globus Toolkit$_{TM}$)에서 사용하는 GASS(Global Access to Secondary Storage)는 원격에 있는 관련 데이터들을 로컬 시스템의 데이터에 접근하는 것처럼 처리하는 것을 지원한다. GASS에서는 원격지의 파일 시스템의 접근시 URL(Uniform Resource Locator)을 이용하는데, 그리드 환경에서의 I/O을 위한 파일 시스템은 복수의 파일 형태로 분산되어있기 때문에 하나의 그리드 응용을 수행할 때 URL을 동적으로 바꿔야 하는 문제점을 갖고 있다. 위치에 상관 없고 고성능을 지향하고 데이터의 성격을 쉽게 표현할 수 있는 이름 체제가 필요하다. 그래서 본 연구는 동적이고 다양한 표현이 가능한 URI(Uniform Resource Identifiers)을 사용하여 그리드 상에서 데이터를 사용하는 방법을 제안하고자 한다.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.316-317
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• 1997

For successful endodontic therapy, complete and accurate biochemical and chemical preparations will allow accurate root canal. Hence the accurate determination of root length is very important for the highest rates of success in endodontic therapy. Among the apex locators, frequency dependent type has higher accuracy and more advantages than others. In this paper, we proposed better frequencies for the method of measuring root canal length by the ratio of two different impedances. It was found that 500Hz and 10kHz is better selection than other frequencies used in the commercial products.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.188-191
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• 1997

In this paper, we present a real-time remote patient monitoring service through world-wide web, which allows the medical doctor to monitor his patients in remote sites using popular web browsers. The real-time service consists of two services: Patient Locator Service (PLS) and Vital Sign Monitoring Service (VSMS). The PLS provides the information of patients currently being monitored. The VSMS allows the user to observe a stream of vital sign data of a specific patient. The vital sign data include ECG, respiration, temperature, $SPO_2$, invasive blood pressure and non-invasive blood pressure.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.709-711
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• 2005

Developing fault location system for underground power cable which can detect its fault location exactly require very high speed data acquisition and signal processing capability. We are developing fault location system which is different from conventional fault locator. This fault location system monitor underground power cable by using on-line speed current sensor and if there are an accident, it record its transient signal and calculate fault location by analyzing it. Signals which acquired when power cable fault arise, showed transient characteristics and its frequency band is very hish. So, to develop fault location system, we designed special high speed data acquisition and signal processing board. In this thesis, we describe on data acquisition and signal processing H/W design for fault location system on underground power cable.