• 구강회복응용과학지
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• 제28권4호
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• pp.371-383
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• 2012

성공적인 근관치료를 위하여 원래 근관 형태를 따르는 근관 성형 과정이 중요하다. 그러나 대부분의 근관은 만곡되어 있고, 근관 성형 기구는 직선의 금속을 기본으로 만들어지기 때문에 근관 성형 후 만곡 근관이 원래 근관 형태를 벗어나는 오류가 나타날 수 있다. 이런 오류들로 인하여 근관 치료가 실패할 수 있으므로 근관 성형시 원래 만곡형태를 유지할 수 있는 다양한 기술과 방법들이 소개되고 있다. 본 연구의 목적은 만곡 근관 형태의 레진 모형을 이용하여 기구의 형태와 사용방법이 다른 세 가지 Ni-Ti 파일을 사용하여 Ni-Ti 파일 종류에 따른 만곡 근관에 대한 성형 후 형태 유지능을 비교하는 것이다. 직경과 경사도가 ISO 15, 0.02인 30개의 레진모형을 사용하였다. 그룹 1은 Profile을 이용하여 #20/.06까지 근관 성형하였고, 그룹 2는 Mtwo를 이용하여 #35/.04까지 근관 성형하였으며, 그룹 3은 PathFile을 이용하여 glide path를 만들어준 다음 WaveOne 파일 중 Primary을 사용하여 근관 성형하였다. 기구 사용 전과 후의 레진모형을 스캔하여 디지털 이미지로 만들었다. 각 이미지를 중첩시킨 다음 Matlab r2010b 소프트웨어를 이용하여 곡률반경의 비(CRr)를 계산하였다. 이를 바탕으로 Ni-Ti file 간 성형 후 형태 유지능을 비교하기 위하여 1-way ANOVA를 이용하여 세 그룹의 CRr의 차이에 대한 유의성 검정을 시행하였다.(P<.05) 또한 continuous rotary system과 single file system간의 형태 유지능을 비교하기 위하여 independent t-test를 이용하였다.(P<.05) 곡률반경의 비(CRr)를 이용하여 Ni-Ti 파일 종류에 따른 만곡 근관의 형태 유지능을 비교한 결과 Ni-Ti file 간에는 통계적으로 유의한 차이가 있었다.(P<0.05) ProFile과 WaveOne은 Mtwo에 비해서 만곡 근관에서의 형태 유지능이 우수하게 나타났다.Ni-Ti 기구 사용 방법에 따른 만곡 근관 형태 유지능을 비교한 결과 continuous rotary system과 single file system 간에는 통계적으로 유의한 차이를 보이지 않았다.(P>0.05) 본 연구결과에 따르면, ProFile과 WaveOne은 Mtwo에 비하여 만곡 근관에서의 형태 유지능이 통계적으로 유의하게 높게 나타났으므로, ProFile과 WaveOne이 만곡근관에 대한 형태 유지능이 우수하다고 할 수 있다. 만곡근관에서의 형태 유지능에 있어서 continuous rotary system과 single file system은 만곡근관에서의 형태 유지능에 차이가 없다.

• 정보학연구
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• 제12권2호
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• pp.49-55
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• 2009

Currently the Web, multiple files in the Client to upload to the server of the multi-upload method, files are stored in specific folders on the server, the file name field in DB(Database Field) stored in a way that the process has been widely utilized. Therefore, a minimum number of file upload as many file names in the Database and the Table should be created in the field, but also a variable number of files can be uploaded has no limits. In this paper we proposed the new method that files to be uploaded to the server, you can upload a limited number of files, nor due to upload files to reduce load on the database to improve the processing speed of a single field using a multi-method file uploads using PHP directly implemented

• Restorative Dentistry and Endodontics
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• 제42권2호
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• pp.140-145
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• 2017

Objectives: The aim of this randomized, controlled, prospective clinical study was to evaluate patients' intraoperative discomfort during root canal preparations in which either multi-file rotary (Mtwo) or single-file reciprocating (Reciproc) systems were used. Materials and Methods: Fifty-five adult patients, aged between 25 and 69 years old, with irreversible pulpitis or pulp necrosis participated in this study. Either the mesiobuccal or the distobuccal canals for maxillary molars and either the mesiobuccal or the mesiolingual canals for mandibular molars were randomly chosen to be instrumented with Mtwo multi-file rotary or Reciproc single-file reciprocating systems. Immediately after each canal instrumentation under anesthesia, patient discomfort was assessed using a 1 - 10 visual analog scale (VAS), ranging from 'least possible discomfort' (1) to 'greatest possible discomfort' (10). The Wilcoxon signed-rank test was used to determine significant differences at p < 0.05. Results: Little intraoperative discomfort was found in all cases. No statistically significant differences in intraoperative discomfort between the 2 systems were found (p = 0.660). Conclusions: Root canal preparation with multi-file rotary or single-file reciprocating systems had similar and minimal effects on patients' intraoperative discomfort.

• 정보처리학회논문지A
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• 제15A권5호
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• pp.275-286
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• 2008

Fast File System(FFS)은 디스크의 고성능 대역폭을 활용하여 대용량 파일의 여러 블록들을 한 번에 저장함으로써 파일 쓰기 성능을 향상시키고 있다. 하지만, FFS는 파일 단위로 데이터를 저장하기 때문에 작은 파일 쓰기 성능은 디스크 대역폭보다 디스크 회전 및 탐색 시간에 크게 영향을 받는다. 본 논문은 FFS에서 작은 파일 쓰기의 성능 향상을 위해 여러 개의 작은 파일들을 한꺼번에 모아서 저장하는 모아 쓰기(Co-Writing) 기법을 제안하며, 이 기법을 FFS에 적용한 CW-FFS를 구현하였다. CW-FFS의 모아 쓰기 기법은 대역폭을 활용하여 디렉토리 지역성을 가지는 작은 파일들을 모아서 연속적인 디스크 위치에 한 번의 디스크 쓰기로 저장한다. 모아 쓰기 기법은 각 파일 단위로 발생하는 디스크 회전 및 탐색 동작들을 한 번으로 감소시키기 때문에 파일 쓰기가 많은 응용 프로그램에서 작은 파일 쓰기 성능을 개선시킨다. 또한 모아 쓰기 기법이 동일 디렉토리에 포함되는 파일들 간의 디스크 공간 지역성의 저하를 야기하지 않도록 효율적인 파일 할당 방식도 함께 제안한다. CW-FFS는 성능 검증을 위해 OpenBSD 운영체제 커널에서 구현되었으며, postmark 벤치마크를 통한 성능 측정 결과는 기존 FFS 파일 시스템보다 작은 파일 쓰기 성능이 속도 측면에서 $5{\sim}35%$까지 개선되었음을 보여준다.

• Journal of Communications and Networks
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• 제10권4호
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• pp.422-429
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• 2008

Mobile peer-to-peer (P2P) systems have recently got in the limelight of the research community that is striving to build efficient and effective mobile content addressable networks. Along this line of research, we propose a new peer-to-peer file sharing protocol suited to mobile ad hoc networks (MANET). The main ingredients of our protocol are network coding and mobility assisted data propagation, i.e., single-hop communication. We argue that network coding in combination with single-hop communication allows P2P file sharing systems in MANET to operate in a more efficient manner and helps the systems to deal with typical MANET issues such as dynamic topology and intermittent connectivity as well as various other issues that have been disregarded in previous MANET P2P researches such as addressing, node/user density, non-cooperativeness, and unreliable channel. Via simulation, we show that our P2P protocol based on network coding and single-hop communication allows shorter file downloading delays compared to an existing MANET P2P protocol.

• 디지털산업정보학회논문지
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• 제10권3호
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• pp.35-40
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• 2014

Many researches have been conducted to achieve improvement in distributed system that connects multiple computer systems via communication lines. Among others, the load balancing and file migration are considered to have significant impact on the performance of distributed system. The dynamic file migration algorithm common in distributed processing system involved complex calculations of decision function necessary for file migration and required migration of control messages for the performance of decision function. However, the performance of this decision function puts significant computational strain on computer. As one single network is shared by all computers, more computers connected to network means migration of more control messages from file migration, causing the network to trigger bottleneck in distributed processing system. Therefore, it has become imperative to carry out the research that aims to reduce the number of control messages that will be migrated. In this study, the learning automata was used for file migration which would requires only the file reference-related information to determine whether file migration has been made or determine the time and site of file migration, depending on the file conditions, thus reflecting the status of current system well and eliminating the message transfer and additional calculation overhead for file migration. Moreover, mathematical model for file migration was described in order to verify the proposed model. The results from mathematical model and simulation model suggest that the proposed model is well-suited to the distributed system.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.33.1-33.10
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• 2020

Objectives: This study was conducted to evaluate the effects of traditional and contracted endodontic cavity (TEC and CEC) preparation with the use of Reciproc Blue (RPC B) and One Curve (OC) single-file systems on the amount of apical debris extrusion in mandibular first molar root canals. Materials and Methods: Eighty extracted mandibular first molar teeth were randomly assigned to 4 groups (n = 20) according to the endodontic access cavity shape and the single file system used for root canal preparation (reciprocating motion with the RCP B and rotary motion with the OC): TEC-RPC B, TEC-OC, CEC-RPC B, and CEC-OC. The apically extruded debris during preparation was collected in Eppendorf tubes. The amount of extruded debris was quantified by subtracting the weight of the empty tubes from the weight of the Eppendorf tubes containing the debris. Data were analyzed using 1-way analysis of variance with the Tukey post hoc test. The level of significance was set at p < 0.05. Results: The CEC-RPC B group showed more apical debris extrusion than the TEC-OC and CEC-OC groups (p < 0.05). There were no statistically significant differences in the amount of apical debris extrusion among the TEC-OC, CEC-OC, and TEC-RPC B groups. Conclusions: RPC B caused more apical debris extrusion in the CEC groups than did the OC single-file system. Therefore, it is suggested that the RPC B file should be used carefully in teeth with a CEC.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권1호
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• pp.52-57
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• 2015

본 논문에서는 SSD의 TRIM 명령어 처리 성능을 LBA 범위의 특성 및 개수에 따라 분석하고, 그 결과를 바탕으로 Ext4 파일 시스템에서의 TRIM 명령어 처리 성능을 개선하였다. 대부분의 SSD에서 LBA 범위의 크기가 크고, 섹터 번호가 정렬 및 연속되어 있으며, 하나의 TRIM 명령어로 다수의 LBA 범위 정보를 전달할수록 TRIM 명령어의 처리 성능이 증가하는 것으로 나타났다. 한편, 기존의 Ext4 파일 시스템은 이와 같이 다수의 LBA 범위 정보를 전달할 때 그 성능이 더 높음에도 불구하고, 하나의 TRIM 명령어 당 하나의 LBA 범위 정보만 전달하는 문제점을 가지고 있다. 이를 해결하기 위해 하나의 TRIM 명령어로 최대 64개의 LBA 범위 정보를 전달하도록 Ext4 파일 시스템을 개선하였고, Filebench를 이용한 성능 평가에서 파일 삭제 성능이 최대 35% 증가하는 것을 확인하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2006년도 학술대회
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• pp.289-295
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• 2006

The Musical Slide Show MAF, which currently being standardized by MPEG, conveys the concept of combining several established standard technologies in a single file format. It defines the format of packing up MP3 audio data, along with MPEG-7 Simple Metadata Profile and MPEG-21 Digital Item Declaration metadata; with JPEC images and optional text, and synchronizes them all together to create a slideshow of JPEC image data associated to MP3 audio data during the audio playback. The implementation of Musical Slide Show MAF can be a music karaoke file where users can sing along while listening to the music, view the JPEG slideshow and reading the lyrics; or a story-telling file where users can listen to the narrated story by looking at the related illustration slideshow of the story In this paper we present the tool to producing the Musical Slide Show MAF contents. Regardless the knowledge of user on the MAF file format, the authoring tool simplify the manner of packaging several multimedia contents into single file.

• Restorative Dentistry and Endodontics
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• 제38권4호
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• pp.222-226
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• 2013

Objectives: The aim of this study was to assess the influence of operator experience level on the lifespan of the WaveOne Primary file (Dentsply Maillefer, Ballaigues, Switzerland) in extracted teeth. Materials and Methods: Moderately curved canals of extracted maxillary and mandibular molars were randomly distributed into 2 groups: experienced and inexperienced operators. Ten files were allocated to each group (n = 10). Each canal was prepared until the working length was reached, and the same file was used to prepare additional canals until it separated. The number of canals prepared before file separation was recorded. The fragment length of each file was measured, and the location of the fragment in the canal was determined. Data were statistically analysed using the independent 2-sample t-test. Results: The 2 operators prepared a total of 324 moderately curved canals of maxillary and mandibular molars. There was no significant intergroup difference in the mean number of canals prepared (p = 0.27). The average lifespan of the WaveOne Primary file was 17.1 and 15.3 canals, and the longest lifespan was 25 and 20 canals, when used by experienced and inexperienced operators, respectively. There were no statistically significant intergroup differences in separated fragment length and location. Conclusions: Within the limitations of this study, operator experience level appears to have no effect on the lifespan of the WaveOne Primary file in preparation of moderately curved canals. Single teeth with multiple canals can be prepared safely even by a novice operator by using a single file.