• Title/Summary/Keyword: Evaluation matrix

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A Study on Evaluation of Thermal Shock Damage of Metal Matrix Composite using Ultrasonics (초음파를 이용한 금속복합재료의 열충격 손상 평가 연구)

  • 강문필;이준현
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.31-37
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    • 2000
  • Metal matrix composites(MMCs) are rapidly becoming one of the strongest candidates for structural materials for many high temperature application. Among the high temperature environment, thermal shock is known to cause significant degradation in most MMC system. Therefore, the nondestructive evaluation on thermal shock damage behavior of SiC/A16061 composite has been carried out using ultrasonic surface and SH-waves. For this study, Sic fiber reinforced metal matrix composite specimens fabricated by a squeeze casting technique were thermally cycled in the temperature range 25~$400^{\circ}C$ up to 1000 cycles. Three point bend test was conducted to investigate the effect of thermal shock damage on mechanical properties. The relationship between thermal shock damage behavior and the change of ultrasonic velocity and attenuation were discussed by considering SEM observation of fracture surface.

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Preparation and Pharmacokinetic evaluation of Captopril Matrix Tablets with Polyethylene Oxide (폴리에틸렌옥시드를 이용한 캅토프릴 매트릭스 정제의 제조 및 약물동력학적 평가)

  • Jiang, Ge;Baek, Myoung-Ki;Jee, Ung-Kil
    • Journal of Pharmaceutical Investigation
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    • v.29 no.1
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    • pp.7-12
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    • 1999
  • The captopril matrix tablets composed of polyethylene oxide(PEO) was prepared and administered to beagle dogs. Captopril matrix tablets were prepared using direct compressed method and wet granulation compressed method with various ratios of drug to PEO. The diffusion rate of captopril matrix tablets followed on the Higuchi's diffusion model. With increasing hardness of captopril matrix tablets, release rate was decreased. Each formulation was evaluated by the area under the curve (AUC) and time course of plasma captopril concentration after oral administration to beagle dogs. The $AUC_{0-12}$ were $9.126\;{\mu}g\;h/ml$ and $6.417\;{\mu}g\;h/ml$ for the matrix tablets and conventional tablets, respectively. Therefore, the bioavailability of captopril matrix tablets was greater than that of commercial product. It is suggested that captopril matrix tablets using PEO is a useful sustained release formulation.

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Study of bone healing pattern in extraction socket after application of demineralized dentin matrix material (자가치아 뼈 이식재의 발치와내 이식 후 골 치유 양상에 관한 연구)

  • Chung, Jae-Ho;Lee, Jae-Hoon
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.37 no.5
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    • pp.365-374
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    • 2011
  • Introduction: Research on dental bone graft material has been actively conducted. Recently, demineralized dentin matrix material has been developed and introduced. This study examined the effect of demineralized dentin matrix material on bone healing. Subjects and Methods: The patients who received no treatment after extraction were used as the control group and patients who underwent demineralized dentin matrix material application in the extraction socket after extraction were used as the experimental group. Panorama radiography was performed at the baseline and at 3.5 months after graft material placement and CT was taken at 3.5 months after graft material placement for a radiologic evaluation. Bony tissue specimens were collected from the alveolar crest in the middle of the extraction socket using a 2 mm trephine bur after 3.5 months for the histology and hostomorphometric study. Results: 1. On the panoramic view, a higher bone density was observed in the subject group. 2. On the panoramic view, the bone density increased significantly in the extraction socket, from the baseline to 3.5 months: a 7 and 10 gray-level scale was observed in the control and experimental group, respectively (P<0.05). 3. The CT view evaluation at 3.5 months revealed significantly higher bone density in the subject group than the control group (P<0.05). 4. The histological findings showed more active new bone and lamellar bone formation in the subject group. Dentin with osteoinduction ability and enamel with osteoconduction ability appeared. 5. On histomorphometric analysis, the subject group showed significantly more new bone, lamellar bone area and lower soft tissue area (P<0.05). The difference between the groups was significant (P<0.05). Conclusion: Bone healing was improved after the application of demineralized dentin matrix material and there was active new bone and lamellar bone formation.

Guided bone regeneration using demineralized allogenic bone matrix with calcium sulfate: case series

  • Kim, Young-Kyun;Lee, Ji-Young;Kim, Su-Gwan;Lim, Seung-Chul
    • The Journal of Advanced Prosthodontics
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    • v.5 no.2
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    • pp.167-171
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    • 2013
  • PURPOSE. The purpose of this case series was to evaluate the effect of guided bone regeneration using demineralized allogenic bone matrix with calcium sulfate. MATERIALS AND METHODS. Guided bone regeneration using Demineralized Allogenic Bone Matrix with Calcium Sulfate ($AlloMatrix^{TM}$, Wright. USA) was performed at the time of implant placement from February 2010 to April 2010. At the time of the second surgery, clinical evaluation of bone healing and histologic evaluation were performed. The study included 10 patients, and 23 implants were placed. The extent of bony defects around implants was determined by measuring the horizontal and vertical bone defects using a periodontal probe from the mesial, distal, buccal, and lingual sides and calculating the mean and standard deviation of these measurements. Wedge-shaped tissue samples were obtained from 3 patients and histologic examination was performed. RESULTS. In clinical evaluation, it was observed that horizontal bone defects were completely healed with new bones, and in the vertical bone defect area, 15.1% of the original defect area remained. In 3 patients, histological tests were performed, and 16.7-41.7% new bone formation was confirmed. Bone graft materials slowly underwent resorption over time. CONCLUSION. $AlloMatrix^{TM}$ is an allograft material that can be readily manipulated. It does not require the use of barrier membranes, and good bone regeneration can be achieved with time.

A Study on the Computerization of Function Evaluation in VE (가치공학(價値工學)에서의 기능평가(機能評價) 전산화(電算化)에 관(關)한 연구(硏究))

  • Lee, Seok-Hwan;Park, No-Guk;Song, Mun-Ik
    • Journal of Korean Society for Quality Management
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    • v.21 no.1
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    • pp.199-213
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    • 1993
  • The function-cost matrix table is not constant, but can be changed by many factors including equipment capacity, level of production technique, fluctuation of production volume, and the continuous development of products. Such changes would give the VE analysists additional work burden. By using computer. in this study, much of the time and effort of the function evaluation could be saved, and the efficiency of the analysis could also be enhanced. The application of the function evaluation data of R Company, as a case analysis, to the function evaluation computer program developed in this study resulted in the faster management of function-cost matrix table and function evaluation.

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An Asymmetry Matrix Transposition Scheme based on NAND Flash Memory (낸드 플래시 메모리 기반의 비대칭 행렬 전치 기법)

  • Kim, Sung-Chul;Park, Woong-Kyu;On, Byung-Won;Lee, Ingyu;Choi, Gyu Sang
    • IEMEK Journal of Embedded Systems and Applications
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    • v.10 no.2
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    • pp.81-89
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    • 2015
  • In this paper, we proposed a new matrix transposition scheme, called asymmetry sub-matrix, and conducted the in-depth performance evaluation of the proposed scheme with other prior schemes, including element-major, row-major and sub-matrix schemes in large-scale matrix. In our results, the proposed asymmetry sub-matrix scheme shows the best performance compared to other prior schemes, while sub-matrix scheme shows the second best performance.

Comparison Between DCM and Quaternion Transformation in Lever Arm Compensation of Reference System for Flight Performance Evaluation of DGPS/INS

  • Park, Ji-Hee;Shin, Dong-Ho
    • Journal of Positioning, Navigation, and Timing
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    • v.1 no.1
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    • pp.45-49
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    • 2012
  • The flight performance evaluation of navigation system is very significant because the reliability of navigation data directly affect the safety of aircraft. Especially, the high-level navigation system such as DGPS/INS, need more precise flight performance evaluation method. The performance analysis is evaluated by comparing between the navigation system in aircraft and reference trajectory which is more precise than navigation system in aircraft. In order to verify DGPS/INS performance of m-level, the GPS receiver, which is capable post-processed Carrier-phase Differential GPS(CDGPS) method of cm-level, have to be used as reference system. The DGPS/INS is estimated the Center of Gravity (CG) point of aircraft to offer precise performance while the reference system is output the position of GPS antenna which is mounted on the outside of aircraft. Therefore, in order to more precise performance evaluation, it needs to compensate the lever arm and coordinates transformation. This paper use quaternion and Direct Cosine Matrix(DCM) methods as coordinate transformation matrix in lever arm compensation of CDGPS reference trajectory. And it compares NED errors of DCM and quaternion transformation in lever arm of reference trajectory via DGPS/INS result.

A Study on Community Revitalization Policy through Analysis of Urban Regeneration Cases -Focussing on the Cases of the Urban Regeneration in the UK, Germany and Korea- (도시재생 사례분석을 통한 커뮤니티 활성화 정책에 관한 연구 -영국·독일·한국의 도시재생 사례를 중심으로-)

  • Jang, Yong Il;Kim, Chang-Sung
    • KIEAE Journal
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    • v.16 no.5
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    • pp.93-101
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    • 2016
  • Purpose : This research aims to present policy plans for community vitality in the field of the urban regeneration project by analyzing aspects for vitality via domestic and abroad city policies and cases. Methods: The research method works as follows: The first step is 1) to introduce the concept of evaluation matrix to analyze cases of urban generation, 2) to apply to the proposed evaluation matrix, and then 3) to analyze communities' decline diagnosis, counterstrategies, and promotion process. And the second step is to draw features and evaluation of cases and to present the policy plan for communities' vitality with the urban regeneration project in South Korea via a comprehensive analysis. Result : This research confirmed the fact that when different sectors is expanded toward a mutual cooperation, communities are vitalized, having a mutual effect on other related sectors by taking a part in the community positively. Especially in the base of each characteristic and estimation, when various activities and socio-economic programs with residents are promoted in the integrated system, communities are successful. Through this results we present four policy plans for community vitality of the urban regeneration project in South Korea.

Numerical Evaluation of MoM Matrix for a General Microstrip Structures (일반적인 마이크로스트립 구조에 관한 MoM 행렬의 수치계산)

  • 이영순;김의중;오병희;조영기
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2001.11a
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    • pp.3-6
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    • 2001
  • In case that a closed-form Green's functions are used for the numerically efficient analysis of a general microstrip structures of thin or thick substrate, an efficient technique for the evaluation of MoM off-diagonal matrix elements as well as diagonal elements is proposed. In order to check the validity of the present method, performance is demonstrated for the example of a coaxially-fed microstrip antenna and the present results are compared with the previous results.

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Clinical evaluation of a collagen matrix to enhance the width of keratinized gingiva around dental implants

  • Lee, Kang-Ho;Kim, Byung-Ock;Jang, Hyun-Seon
    • Journal of Periodontal and Implant Science
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    • v.40 no.2
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    • pp.96-101
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    • 2010
  • Purpose: The purpose of this study was to evaluate the effect of collagen matrix with apically positioned flap (APF) on the width of keratinized gingiva, comparing to the results of APF only and APF combined with free gingival graft (FGG) at the second implant surgery. Methods: Nine patients were selected from those who had received treatments at the Department of Periodontics, Chosun University Dental Hospital, Gwangju, Korea. We performed APF, APF combined with FGG, and APF combined with collagen matrix coverage respectively. Clinical evaluation of keratinized gingival was performed by measuring the distance from the gingival crest to the mucogingival junction at the mid-buccal point, using a periodontal probe before and after the surgery. Results: The ratio of an increase was 0.3, 0.6, and 0.6 for the three subjects in the APF cases, 3, 5, and 7 for the three in the APF combined with FGG case, and 1.5, 0.5, and 3 for the three in the APF combined with collagen matrix coverage case. Conclusions: This study suggests that the collagen matrix when used as a soft tissue substitute with the aim of increasing the width of keratinized tissue or mucosa, was as effective and predictable as the FGG.