• 제목/요약/키워드: IRM

검색결과 118건 처리시간 0.024초

잔존 상아질 후경에 따른 S. mutans의 성견 치수반응에 관한 실험적 연구 (AN EXPERIMENTAL STUDY OF THE EFFECT OF S. MUTANS ON THE PULP IN RELATION TO THE REMAINING DENTIN THICKNESS)

  • 김형동
    • Restorative Dentistry and Endodontics
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    • 제15권2호
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    • pp.34-45
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    • 1990
  • The purpose of this study was to evaluate the pulpal responses of S. mutans (6715, serotype A) in relation to the remaining dentin thickness. The material was consisted of 72 teeth from 6 dogs. Cl. V cavities were prepared into 2 different thickness (0.5mm, 1.0mm) of remaining dentin. In the control groups, the cavities were filled with filter paper of broth, tin foil, and IRM$^{(R)}$ cement. In the experimental groups, the cavities were filled with filter paper of S. mutans, filter paper of broth, tin foil, and IRM$^{(R)}$ cement. The intervals of observation period were 1 week, 3 weeks, and 8 weeks respectively after the experiment. The specimens were fixed with 10% formalin and decalcified in 5% nitric acid. All specimens were stained with Hematoxylin-Eosin and examined histopathologically under the microscope. The results were as follows. 1. The changes and congestion of odontoblastic layers were more frequent and lasting in the control group of 0.5mm than in that of 1.0mm remaining dentin thickness. 2. There was no characteristic difference between the control group of 1.0mm and the experimental group of 1.0mm in all pulp responses. 3. Acute and chronic inflammatory cells were seen in the experimental group of 0.5mm, but not seen in the control group of 0.5mm.

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원심펌프 관로계에 대한 임펄스 응답법 적용 연구 (Impulse response method for a centrifugal pump in pipeline systems)

  • 허지성;김현준;송용석;김상현
    • 상하수도학회지
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    • 제30권5호
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    • pp.481-489
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    • 2016
  • Method of characteristic(MOC) has been widely used as a transient analysis technique for pressurized pipeline systems. There are substantial studies using MOC for the water hammer triggered through instantaneous valve closures, pump stoppage and pump startup for pipelines systems equipped with a centrifugal pump. Considering restrictions of MOC associated with courant number condition for complicated pipeline systems, an impulse response method(IRM) was developed in the frequency domain. this study implements the impact of centrifugal pump using transfer function in frequency domain approach. Using pump performance curve and the affinity law, this study formulated transfer functions which relate complex pressure head at upstream of pump system to that of downstream location. Simulations of simple reservoir-pump-valve system using IRM with formulated transfer function were similar to those obtained through MOC.

치수절단 후 Aucubin이 잔존치수조직에 미치는 영향에 관한 연구 (A STUDY OF THE EFFECTS OF AUCUBIN ON THE PULP TISSUE AFTER PULPOTOMY IN DOGS)

  • 백승호;이승우
    • Restorative Dentistry and Endodontics
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    • 제24권4호
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    • pp.554-559
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    • 1999
  • Aucubin, an iridoid glucoside isolated from Aucuba japonica, has pharmacological effects such as antimicrobial effect, liver protective function and inhibition of liver RNA and protein biosynthesis, etc. This study was performed to observe the effect of aucubin on the pulp tissue after pulpotomy. Aucubin was converted to aucubinogenin as an active form by ${\beta}$-glucosidase. In 3 Mongrel dogs, the pulps were mechanically exposed with a sterile round bur and excised with sterile excavator. After bleeding control, aucubin was applied on remaining pulp tissues and then they were sealed with IRM in experimental group. In control group, $Ca(OH)_2$ powder was applied on remaining pulp tissues and then they were sealed with IRM. After interval of 1 and 12 weeks, the dogs were sacrificed. The teeth were prepared for histologic evaluation and examined by light microscope. Aucubin 1 week group showed that mild inflammation and vascular congestion in most of the specimen. More various degree of inflammation was found in experimental group than in control group. Premature calcified mass were found in the both 1 weeks groups. Continuous well-formed dentin bridge was found in both 12 weeks groups. Collectively, this study suggests that the possibility of aucubin as a medicament after pulpotomy.

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Wet adhesion and rubber friction in adhesive pads of insects

  • Federle, Walter
    • 접착 및 계면
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    • 제5권2호
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    • pp.31-42
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    • 2004
  • Many animals possess on their legs adhesive pads, which have undergone evolutionary optimization to be able to attach to variable substrates and to control adhesive forces during locomotion. Insect adhesive pads are either relatively smooth or densely covered with specialized adhesive hairs. Theoretical models predict that adhesion can be increased by splitting the contact zone into many microscopic, elastic subunits, which provides a functional explanation for the widespread 'hairy' design. In many hairy and all smooth attachment systems, the adhesive contact is mediated by a thin film of liquid secretion between the cuticle and the substrate. By using interference reflection microscopy (IRM), the thickness and viscosity of the secretion film was estimated in Weaver ants (Oecophylla smaragdina). 'Footprint' droplets deposited on glass are hydrophobic and form low contact angles. IRM of insect pads in contact showed that the adhesive liquid is an emulsion consisting of hydrophilic, volatile droplets dispersed in a persistent, hydrophobic phase. I tested predictions derived from film thickness and viscosity by measuring friction forces of Weaver ants on a smooth substrate. The measured friction forces were much greater than expected assuming a homogenous film between the pad and the surface. The findings indicate that the rubbery pad cuticle directly interacts with the substrate. To achieve intimate contact between the cuticle and the surface, secretion must drain away, which may be facilitated by microfolds on the surface of smooth insect pads. I propose a combined wet adhesion/rubber friction model of insect surface attachment that explains both the presence of a significant static friction component and the velocity-dependence of sliding friction.

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정보시스템 성능측정 방법에 관한 탐색적 연구 - 통합전산센터 사례를 중심으로 - (An Exploratory Study on Performance Measure for Information System - Focus on NCIA's Cases -)

  • 나종회;최광돈
    • 디지털융복합연구
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    • 제8권4호
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    • pp.205-213
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    • 2010
  • 오늘날 정보자원관리는 정보시스템 조직에 있어서 매우 중요한 요소이다. 따라서 민간부문 뿐만 아니라 많은 공공기관 역시 정보자원에 대한 관리를 강화하고 있다. 특히, 이러한 정보자원관리의 핵심 요소 중 하나가 서버의 성능관리이다. 따라서 서버의 성능을 결정하는 것은 서버의 구매조직에 있어서 중요한 이슈이다. 본 논문에서는 공공부문 정보화사업을 중심으로 서버의 성능측정 및 검증, 성능 측정 관련 국내 현황, 통합전산센터의 사례들 토대로 공공부문의 도입서버의 성능측정 및 검증 관련 이슈와 문제점 등을 살펴보고 성능측정 및 검증 관련 이슈와 문제점에 대한 해결방안으로 서버 성능에 영향을 미치는 요소를 재시하였으며, 아울러 공공부문의 환경적 요인을 고려한 서버의 성능측정 및 검증방안을 제시한다.

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Information Resource Management (IRM) : Empirical Study in the Service Industry

  • Ha, Tae-Hyun
    • 한국산업정보학회논문지
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    • 제4권2호
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    • pp.14-22
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    • 1999
  • 이 연구의 목적은 주요한 정보의 원천은 무엇이며, 정보 자원 관리에서 부딪치는 문제점을 파악하여 가능한 해결방안을 제시하는 것이다. 즉, 구체적으로 문자정보, 의사소통 그리고 정보활용기술을 통해 정보를 얻고 관리하는 데 있어 직위가 다른 경우 (책임자, 일반직원, 노조 대의원) 이 다른 원천들의 중요성을 얼마나 잘 알고 또한 인식하고 있으며 이 원천들에 대한 그들의 태도는 어떠한 가를 조사해 보려는 것이다. 연구의 결과 내부 정보 자원이 가장 중요하고 가장 많이 이용되고 있다. 정보 활용기술의 시설에 대해서는 가격은 저렴해지고 있는 반면 그 기능은 매우 향상됨에 따라 그 중요성이 증대되고 있으나, 그 사용은 쉬운 것에 제한 되고있어 경영자는 효율적 사용을 극대화 하기 위해서는 좀더 많은 관심과 철저한 교육 훈련이 있어야 함을 제시하고 있다.

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Affection-enhanced Personalized Question Recommendation in Online Learning

  • Mingzi Chen;Xin Wei;Xuguang Zhang;Lei Ye
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제17권12호
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    • pp.3266-3285
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    • 2023
  • With the popularity of online learning, intelligent tutoring systems are starting to become mainstream for assisting online question practice. Surrounded by abundant learning resources, some students struggle to select the proper questions. Personalized question recommendation is crucial for supporting students in choosing the proper questions to improve their learning performance. However, traditional question recommendation methods (i.e., collaborative filtering (CF) and cognitive diagnosis model (CDM)) cannot meet students' needs well. The CDM-based question recommendation ignores students' requirements and similarities, resulting in inaccuracies in the recommendation. Even CF examines student similarities, it disregards their knowledge proficiency and struggles when generating questions of appropriate difficulty. To solve these issues, we first design an enhanced cognitive diagnosis process that integrates students' affection into traditional CDM by employing the non-compensatory bidimensional item response model (NCB-IRM) to enhance the representation of individual personality. Subsequently, we propose an affection-enhanced personalized question recommendation (AE-PQR) method for online learning. It introduces NCB-IRM to CF, considering both individual and common characteristics of students' responses to maintain rationality and accuracy for personalized question recommendation. Experimental results show that our proposed method improves the accuracy of diagnosed student cognition and the appropriateness of recommended questions.

How image-processing parameters can influence the assessment of dental materials using micro-CT

  • Torres, Fernanda Ferrari Esteves;Jacobs, Reinhilde;EzEldeen, Mostafa;de Faria-Vasconcelos, Karla;Guerreiro-Tanomaru, Juliane Maria;dos Santos, Bernardo Camargo;Tanomaru-Filho, Mario
    • Imaging Science in Dentistry
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    • 제50권2호
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    • pp.161-168
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    • 2020
  • Purpose: The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). Materials and Methods: Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro-CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 ㎛, as well as different software tools(post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test(P<0.05). Results: Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 ㎛. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 ㎛, and for Biodentine at 20 ㎛. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. Conclusion: Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.

정보시스템 구축시 컴퓨터 하드웨어의 선정전략 - T 철강회사의 시스템 선정 사례 - (A computer Hardware Selection Strategy for Information Systems Development : A Case of T Coil Service Center)

  • 유상진;장영택
    • Asia pacific journal of information systems
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    • 제3권2호
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    • pp.3-54
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    • 1993
  • Recently, executives learned of the strategic impact that information systems (IS) and information technology (IT) could provide to their organizations. In other words, through IS/IT companies could squelch competition, secure suppliers, obtain customer loyalty, reduce the threat of new entrants, and identify new opportunities. Because of these potential benefits, organizations are investing ever-increasing amount of organizational resources in IS/IT to make their organizations as information-based ones. Information-based organizations depend largely upon computer hardwares and softwares for their ongoing operations and management. Thus, organizations must manage their information resources, especially hardwares and softwares very effectively to remain competitive. Information resource management (IRI) is a program of activities directed at making effective use of information technology within an organization. These activities cover from corporate IS/IT planning to application system development, implementation, and maintenance. In more detail, IRV activities include planning for and acquiring computer hardwares and communication equipments, planning for, selection, and management of software development projects, and re-engineering business processes as IS/IT are integrated into organizational management. Among these activities, planning for and acquisition of computer hardwares, and planning for and management of software projects are the most critical ones since these activities require enormous amount of such important corporate resources as money, people, and time. Furthermore, corporate's eventual success largely depends upon whether corporate's policy on IS/IT is effective one or not. Numerous approaches and concepts to specific IRM activities have been proposed. However, many organizations have experienced various problems in the process of applying these approaches to their IRM activities mainly because existing methodologies and guidelines are too general to adapt to each firm's unigue situation. Also, these approaches are having its own strengths and weaknesses. Thus, people in charge of organization's IRM policy should come up with effective guidelines to maintain his position very long. In this study, we reviewed some existing approaches for planning, evaluation, and acquisition of computer hardware. Then, real experiences from Taechang Steel Co., Ltd. located in Taegu, which is one of the largest Coil Service Centers in Korea, are discussed. The major purposes of the study are : (1) to discuss the tradeoffs of existing approaches on hardware evaluation and acquisition, (2) to provide a real experience of a company to facilitate the application of theoretical concepts to the real environment.

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수산화칼슘 적용에 따른 상아질 접착제의 접착강도 변화에 관한 연구 (EFFECT OF CALCIUM HYDROXIDE ON BOND STRENGTH OF DENTIN BONDING SYSTEMS)

  • 박노훈;박상혁;최기운;박상진
    • Restorative Dentistry and Endodontics
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    • 제32권3호
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    • pp.198-207
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    • 2007
  • 본 연구는 다양한 접착 과정과 기전을 지닌 4종의 상아질 접착제를 이용하여 수산화칼슘의 사용 여부 및 그 적용 기간이 접착강도에 미치는 영향을 측정 및 평가하고 주사전자현미경을 이용한 접착 계면의 관찰을 통해 복합레진 수복이나 레진 시멘트를 이용한 수복물 접착 시에 적절한 상아질 접착제의 선택과 사용방법을 알아보고자 시행하였다. 치수강에 근접한 상아질 표면을 노출시킨 후, $Ca(OH)_2$를 생리식염수와 혼합하여 실험군 치아 24개의 상아질 표면에 적용한 후, IRM (Intermediate Restorative Material, Dentsply Caulk, Milford, USA)으로 적용된 수산화칼슘 및 변연 부위의 상아질과 법랑질 모두를 밀폐하여 $36.5^{\circ}C$ 증류수에서 실험기간 (7일 및 30일) 동안 보관하였다. Scotchbond Multipurpose, Single Bond, SE Bond and Prompt L-Pop 등 4종의 상아질 접착제를 제조사의 지시에 따라 적용하고 복합 레진을 3회에 나누어 총 5 mm 높이로 적층한 뒤 각 층마다 20초씩 광조사를 시행하였다. Universal testing machine을 이용하여 1mm/min의 crosshead speed로 하중을 가하여 미세인장 접착 강도를 측정하고 파단면을 주사전자현미경으로 관찰하였다. 이상의 연구 결과에서 단기간 (7일 또는 30일간)의 수산화칼슘 적용은 상아질 접착제의 접착 과정의 차이에 따른 변화를 나타내지 않는 것으로 평가되었다.