• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.11-14
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• 1998

This paper introuces a new efficient method of synchronization acquisition which is the most important element in DS-CDMA system using the phase offset of binary code. This approach uses the binary code function which can easily estimate the phase offset from the received spreading waveforms which respect to the receiver-stored replica of the spreading code. This paper proposes the initial acquisition model with repeat error control device that is good for perfomance. The hardware is implemented by TMS320c30

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.31-36
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• 2000

High temperature and pressure materials in power plant are degraded by creep damage, if they are exposed to constant loads for long times, which occurs in the load bearing structures of pressurized components operating at elevated temperatures. Many conventional measurement techniques such as replica method, electric resistance method, and hardness test method for measuring creep damage have been used. So far, the replica method is mainly used for the Inspection of High temperature and pressure components. This technique is, however, restricted to applications at the surface of the testpieces and cannot be used to material inside. In this paper, ultrasonic evaluation for the detection of creep damage in the form of cavaties on grain boundaries or integranular microcracks are carried out. And the absolute measuring method of quantitative ultrasonic velocity technique for Cr-Mo material degradation is analyzed. As a result of ultrasonic tests for crept specimens, we find that the sound velocity is decreased as the increase of creep life fraction$({\Phi}_c)$ and also, confirmed that hardness is decreased as the increase of creep life fraction$({\Phi}_c)$ but the coefficient of ultrasonic attenuation is increased as the increase of creep life fraction$({\Phi}_c)$. Finally based on the result in this paper, it can be recognized that the ultrasonic techniques using velocities and attenuation coefficient factor are very useful non-destructive methods to evaluate the degree of material degradation in fossile power plants.

• Journal of Technologic Dentistry
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• v.42 no.1
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• pp.9-16
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• 2020

Purpose: The purpose of this study was to compare the marginal and internal fit of lithium disilicate ceramic inlay produced by heat pressing that inlay pattern made by subtractive manufacturing and additive manufacturing method. Methods: A mandibular lower first molar that mesial occlusal cavity (MO cavity) die was prepared. After fabricating an epoxy resin model using a silicone impression material, epoxy resin die was scanned with a dental model scanner to design an MO cavity inlay. The designed STL pile was used to fabricate wax patterns and resin patterns, and then lithium disilicate ceramic inlays were fabricated using hot-press method. For the measurement of the marginal and internal gap of the lithium disilicate, silicone replica method was applied, and gap was measured through an optical microscope (x 80). Data were tested for significant differences using the Mann-Whitney Utest. Results: The marginal fit was 103.56±9.92㎛ in the MIL-IN group and 81.57±9.33㎛ in the SLA-IN group, with a significant difference found between the two groups (p<0.05). The internal fit was 120.99±17.52㎛ in the MIL-IN group and 99.18±6.65㎛ in the SLA-IN group, with a significant difference found between the two groups (p<0.05). Conclusion: It is clinically more appropriate to apply the additive manufacturing than subtractive manufacturing method in producing lithium disilicate inlay using CAD/CAM system.

• Journal of Korea Multimedia Society
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• v.11 no.7
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• pp.928-939
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• 2008

The grid database management system is used for large data processing, high availability and data integration by grid environment. It has a replica for processing performance and high availability in each node. The grid database has a problem of inconsistency, when the update is occurred with a coincidently frequent. To solve this problem, in this paper proposed a version management method for consistency in the grid database. Proposed version manager manages a version of each replica. The version manager keeps a consistency of update operation when is occurred at each node by using a pending queue and waiting queue. Also the node keeps a consistency using a priority queue. So, proposed method has stable and fast update propagation. The proposed method shows stable and faster update propagation than traditional method by performance evaluation.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.124-129
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• 2017

PURPOSE. This study evaluated the effect of span length on the adaptation of implant-supported cobalt chromium frameworks fabricated by three techniques. MATERIALS AND METHODS. Models with two solid abutment analogs at different inter-abutment distances were digitized using a laboratory scanner. Frameworks of two-, three-, and four-unit fixed prostheses were designed by a computer. Six dots with a diameter of 0.2 mm were preset on the surface of each framework. A total of 54 implant-supported cobalt chromium frameworks were fabricated by milling, selective laser melting (SLM), and cast techniques. The frameworks were scanned and exported as Stereolithography files. Distances between two dots in X, Y, and Z coordinates were measured in both the designed and fabricated frameworks. Marginal gaps between the framework and the abutments were also evaluated by impression replica method. RESULTS. In terms of distance measurement, significant differences were found between three- and four-unit frameworks, as well as between two- and four-unit frameworks prepared by milling technique (P<.05). Significant differences were also noted between two- and three-unit frameworks, as well as between two- and four-unit frameworks prepared by cast technique (P<.05). The milling technique presented smaller differences than the SLM technique, and the SLM technique showed smaller differences than the cast technique at any unit prostheses (P<.05). Evaluation with the impression replica method indicated significant differences among the span lengths for any fabrication method (P<.05), as well as among the fabrication methods at any unit prostheses (P<.05). CONCLUSION. The adaptation of implant-supported cobalt chromium frameworks was affected by the span length and fabrication method.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.173-177
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• 1997

Bacillus licheniformis 9945a releases a natural ${\gamma}-poly(glutamic\;acid)({\gamma}-PGA)$ into fermentation broth and shows a mucoid phenotype on the solid agar medium. Transformation of mucoid cells of Bacillus species has not been simple and straightforward. The transpositional activity of Tn10 in B. licheniformis also has not been own either. Thus, a spontaneous non-mucoid derivative of the B. licheniformis was obtained first. Shuttle vector pHV1248 containing mini-Tn10 was introduced into the non-mucoid derivative by the method of protoplast transformation. The resulting transformant was reverted to the wild mucoid phenotype, and then mutated randomly with the mini-transposon by heat induction. Auxotrophs requiring arginine, lysine, or tryptophan were isolated by replica plating method. Southern blotting and DNA-DNA hybridzation analysis showed that these auxotrophs were generated by mini-Tn10 insertion into the chromosomal DNA. This method of transformation and mutation using pHV1248 would be useful for the generation of diverse mutants of B. licheniformis 9945a.(Received January 24,1997; accepted March 10, 1997)

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.153-158
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• 2007

Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.

• Applied Microscopy
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• v.26 no.4
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• pp.447-456
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• 1996

Fracture surfaces of materials contain useful information ranging from crack path to the mechanism of fracture. Since limitation of electron transparency requires a sample in the form of thin foil for TEM observations, it is impossible to extract such information directly from the fracture surfaces. In this study, the method of surface replication from the ceramic fracture surface is employed to characterize the process of crack propagation in ceramic matrix composites using TEM analysis. The surface replica from the fracture surface in ceramic materials provides detailed surface morphology and more importantly, loosened particles on the fracture surface are collected. Electron diffraction and chemical composition analyses of these particles reveal crack path in the specimen. Furthermore, one can determine the mode of fracture by observing the fracture surface morphology from the image of replica. Two examples are given to illustrate the potential of the surface replication technique. In the first example, apparent toughness increase in $B_{4}C-Al$ composites at high strain rate is investigated by surface replication to elucidate the mechanism of fracture at different strain rates. The polytypes of SiC formed during the sintering of SiC-AlN composite and their effect on the fracture behavior of SiC-AlN composite are analyzed in the second example.

• International Journal of Control, Automation, and Systems
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• v.4 no.3
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• pp.344-350
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• 2006

The software GPS receivers based on the SDR technology provide the ability to easily adapt the other signal processing algorithms without changing or modifying the hardware of the GPS receiver. However, it is difficult to implement the software GPS receivers using a commercial processor because of the heavy computational burden for processing the GPS signals in real-time. This paper proposes an efficient GPS signal processing scheme to reduce the computational burden for processing the GPS signals in the software GPS receiver, which uses a fundamental notion compressing the replica signals and the encoded look-up table method to generate correlation values between GPS signals and replica signals. In this paper, it is explained that the computational burden of the proposed scheme is much smaller than that of the typical GPS signal processing scheme. Finally, the processing time of the proposed scheme is compared with that of the typical scheme, and the improvement in the aspect of the computational burden is also shown.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.211-215
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• 2010

지금까지 병원에서 사용하던 일반 종이차트를 벗어나 전자적으로 환자의 데이터를 기록하고 유전자 데이터를 이용하여 환자의 유사 질병까지 찾아 낼 수 있는 EMR(Electronic Medical Record 전자 의무 기록)이 개발되면서 의료계는 환자에게 더욱 신속하고 정확한 진료를 할 수 있게 되었다. 본 논문은 이에 그리드 환경을 접목하여 더 빠른 데이터 처리와 신뢰성 과 접근성을 높일 수 있는 방법을 제시한다. 첫째, 현재 기 개발된 EMR 시스템의 환경에서 인증된 사용자만이 스토리지에 접근 할 수 있도록 GSI Service를 이용하여 단일 인증 방식으로 보안성을 높이며 동시에 단 한번의 인증절차로 모든 자원을 활용 할 수 있다. 둘째, Replica Service를 이용하여 기존의 스토리지를 복제 하여 중요한 데이터 들을 보호하며 다수의 접근이 발생할 경우 처리를 분산 시킬 수 있는 방법을 제시한다. 그리드 미들웨어인 글로 버스가 스토리지와 서버 상에서 CA인증을 담당하며 파일 전송을 담당하는 RFT는 스토리지의 Replica를 관리하는 RLS서버의 정보를 사용 하여 멀리 떨어져 있는 복제된 데이터와의 관계를 기억하고 접근시 가장 가용성이 뛰어난 머신에서 데이터를 불러온다. 이런 글로버스의 서비스 들은 중요하며 고용량이 데이터를 분산 시킴으로써 데이터의 지역성을 높여 재사용 혹은 동시 접근시 처리 시간을 단축 시킬 수 있다. 본 논문은 그리드 환경을 접목하여 이러한 서비스를 구현할 경우 높은 신뢰성과 접근의 신속성을 보장할 수 있다고 제시한다.