• 디지털융복합연구
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• 제18권5호
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• pp.249-256
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• 2020

세션 시작 프로토콜(Session Initiation Protocol, SIP)은 인터넷 프로토콜 기반 네트워크에서 세션 생성과 관리 및 종료하는데 사용되는 신호 프로토콜이다. 이를 통해 음성 기반 전자 상거래나 인스턴트 메시징과 같은 서비스를 구현할 수 있다. 최근에 Qiu등은 SIP를 위한 개선된 패스워드 인증 기법을 제안하고 모든 알려진 공격에 안전하다고 주장하였다. 하지만, 본 논문에서는 Qiu등의 인증 기법이 오프라인 패스워드 추측 공격에 취약하고 서비스 거부의 문제가 있음을 도출한다. 또한, 이러한 문제를 해결하기 위한 강화된 패스워드 인증 기법을 제안한다. 제안한 기법은 서버의 검증자를 사용하지 않고 타원곡선암호의 기본 연산을 활용한다. 정형화된 보안 검증 툴인 ProVerif에 기반한 보안 검증을 제시한다. 보안 분석을 통해 본 논문에서 제안한 강화된 인증 기법이 SIP 상의 다양한 보안 공격에 안전함을 보인다.

• The Journal of Advanced Prosthodontics
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• 제3권3호
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• pp.113-118
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• 2011

PURPOSE. The objective of the present study was to evaluate the effect of five different metal framework designs on the fracture resistance of the metal-ceramic restorations. MATERIALS AND METHODS. For the purpose of this study, the central incisor tooth was prepared, and the metal analogue of it and a master die were fabricated. The counter die with the 0.5 mm clearance was used for fabricating the wax patterns for the metal copings. The metal copings with five different metal framework designs were designed from Group 1 to 5. Group 1 with the metal collar, Group 2, 3, 4 and 5 with 0 mm, 0.5 mm, 1 mm and 1.5 mm cervical metal reduction respectively were fabricated. Total of fifty metal ceramic crown samples were fabricated. The fracture resistance was evaluated with the Universal Testing Machine (Instron model No 1011, UK). The basic data was subjected to statistical analysis by ANOVA and Student's t-test. RESULTS. Results revealed that the fracture resistance ranged from 651.2 to 993.6 N/$m^2$. Group 1 showed the maximum and Group 5 showed the least value. CONCLUSION. The maximum load required to fracture the test specimens even in the groups without the metal collar was found to be exceeding the occlusal forces. Therefore, the metal frameworks with 0.5 mm and 1 mm short of the finish line are recommended for anterior metal ceramic restoration having adequate fracture resistance.

• Journal of Periodontal and Implant Science
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• 제30권2호
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• pp.443-455
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• 2000

The aim of periodontal therapy is a removal of a bacterial plaque butthe instrumentation for plaque control has two nature : removal of a bacterial plaque and increase of surface roughness. Complication of instrumentation is enable to damage to the root surface and artificial crown. Therefore this study was conducted to evaluate the effects of repeated instrumentation on the marginal portion of artificial crown. Fifteen proximal surfaces of ten extracted periodontally diseased maxillary first molars were used. The finish line was placed on the root surface, and then the crown was casted and cemented in usual manner. Three kinds of instruments: hand curet, ultrasonic scaler, and ultrasonic curet were used. After instrumentation, final polishing was done with rubber cup and pumice. And surface changes were evaluated by stereomicroscope and scannig probe microscope. Roughness was increased after instrumentation in all groups, and was decreased after polishing except ultrasonic scaler group. Roughness in the ultrasonic scaler group was lower than others, and roughness after polishing in the hand curet group was lower than others. These results indicate that polishing procedure is recommended, because periodontalinstruments increase the surface roughness and induce the irreversible damage to the marginal portion.

• 복식
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• 제27권
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• pp.163-171
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• 1996

As the current stage of the fashion begins to follow the styles of the past the study on he past costume is getting more importance and as the methodology of the study the accurately ap-proached study through the rehabilitation of the past costume is more needed than the simple re-arrangement of the historical documents. By this methodology this study can be positioned as a re-creation activity. The results of the study are as follows. 1) Style: The S-line silhouette remains be-cause of the straight silhouette or the blossom style bodice. This dress has various types of sil-houette but generally it forms one silhouette and is one-piece. 2) color and Material: The material varies hile the color is divided as the main color of ivory and the stress color of brown. This shows not only that the material has been varied but also that they tried to reduce the monotony. 3) Pattern and Sewing: The simple external figure and the previous stage typically shows the movement to the simplicity of the contemporary and the num-ber of patterens is plenty and the sewing method is also complex. 4) Detail. To overcome the simplicity of the style and to show the characteristics of the afternoon dress the skunk fur the net the sash, and the bow are used. 5) Structural Characteristics: The front open-ing the back opening and the side opening coexists in one-pieced dress and this forms unique structure and complex fastening device. The ribbon tape and casing not only finish the seam but also fix the shape of the dress. Synthetically the 1913-14 afternoon dress has the characteristics of transitional stage in which the characteristics of the costume of 1910s and the remnants of the characteristics of the pre-vious costume style and shows the character-istics of afternoon dress well in terms of the ma-terial the structure and the detail.

• 한국임상수의학회지
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• 제15권2호
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• pp.427-431
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• 1998

This study was undertaken to investigate the effect of exercise induced pulmonary hemorrhage(EIPH) on the finishing position of racehorses, 400 bleeders(305: 1 time, 76: 2 times, 19: 3 times, total: 514 cases) which had bled(EIPH) from their nostrils after their races at the Seoul racecourse during the 5 years period('93-'97) were analyzed for this study. The ratio of bleeders to total racehorses in finishing position 1-3,4-6, 7-9 or above 10 was 0.55, 0.84, 0.90 or 1.13%, respectively. There is tendency to higher incidence of bleeding in the later positioned racehorses group. To analyze the correlation between EIPH and finishing position, finishing potion of each EIPHed horses' was checked at 7 successive races(3 races each before/after EIPH. The average final position at the -3rd race, -2nd racer -lst racer EIPHed race, 1st race,2nd race and 3rd race of each bleeder was 5.85. 5.94, 6.21, 7.32, 7.20, 6.51 and 6.53, respectively. Raring times were adjusted to 1,000 m equivalent. Average racing times of the -3rd race,-2nd racer -lst raced EIPHed race, 1st race, 2nd race and 3rd race of each bleeder was 67.1, 67.1, 67.2, 67.6, 67.5, 67.4 and 67.3 second, respectively. Bleeders which finished the race within 1 second following the winners were 25. 3% of total bleeders. The rest 74.7% reached at the finish line 1 second later than the winners. Particularly 46.3% of bleeders were above 2 second later. Therefore this study suggested that bleeding has effect on performance of the racehorse, consequently it make bleeders be placed later positions.

• 구강회복응용과학지
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• 제19권3호
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• pp.207-217
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• 2003

The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the incisal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ}$, $8^{\circ}$, $12^{\circ}$) of the lower central ncisor. After 10 metal dies were made for each group, the IPS Empress ceramic crowns were fabricated and each crown was cemented on each metal die with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a universal testing machine was used to measure the fracture strength. The results of this study were as follows : The fracture strength of the ceramic crown with 2.0mm depth and $12^{\circ}$ inclination was the highest (648 N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength (482 N). There were no significant differences of the fracture strength by axial inclination in same incisal depth group. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the margin irrespective of incisal depth. There had correlation between fracture strength and fractured surface area.

• 보건행정학회지
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• 제2권2호
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• pp.57-89
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• 1992

This study is aimed both to reorient the Health net-works focused to Health Subcenters in times of development of local autonomy in Korea and to collect the fundamental data such as attitude and practice of the directors of Health Subcenter. The materials are collected from 134 out of 258 sampling directors of Health Subcenters with a questionaire by mailing(respond rate 51.9%). The major findings of this fundamental data are as follows. 1. Current average number of outpatients cared by a director of Health Subcenter is found to be 21.6. 2. The directors of Health Subcenter have little deducted hours for Public Health Programme. 3. Number of the Preventive Health Programme worked by a director of Health Subcenter is from 0 to 3. The most major group worked only 1 programme marked at 69.4%. 4. The directors of Health Subcenter express approval opinin marked at 80.2% that their qualification to appoint has to finish intern course. 5. The average diagnosis allowance a month is approximately twenty hundred thousand won. 6. Most of Health Subcenter(market at 94%) adopted a self-supporting account system. 7. The most complaining subject of directors of Health Subcenter is their working environment. The second complaining subject is governmental officier's interference. 8. The average number of outpatients cared by a director of Health Subcenter is found to be certain differentials by their marriage and the duration of employment. Some proposals of development on Health Subcenter based on the result of this research is as follows : 1. The reorganization on Health Subcenter under line of National Health Center Net-work 2. The psychological reorientation of directors of Health Sucenter and officers. 3. Autonomy management of Health Subcenter. 4. Reorientation of status on directors of Health Subcenter.

• 디지털융복합연구
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• 제17권10호
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• pp.427-432
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• 2019

본 연구의 목적은 환경 문제에 대한 시대적 배경과에 맞추어 일본의 대표적인 친환경 건축가인 후지모리 테루노부 작품에 나타나는 공간표현 특성을 알아보고자한다. 연구 방법으로는 1990년대부터 현재까지의 작품 중 그를 대표하는 다실 공간 5곳을 선정하여 문헌연구를 통하여 공간의 표현 특성을 알아보고자 한다. 분석결과로는 반드시 자연소재를 사용하여 공간을 마감 하고 건축물에 식물을 도입하는 전략을 적극적으로 사용하고 있었다. 일본의 전통방식을 차용하는 전략은 공상성과 일탈성을 나타내는 공간표현 방식으로 사용하고 있었다. 이 시대에 새로움을 추구하는 현대인들의 요구와 실현 가능한 대안의 친환경 건축 계획 시 또 다른 공간디자인 방법론으로 제시할 수 있다고 기대해 본다.

• 한국산업보건학회지
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• 제6권1호
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• pp.1-16
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• 1996

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

• 대한치과보철학회지
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• 제43권5호
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• pp.611-621
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• 2005

State of problem: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. Purpose: This study was to evaluate the at of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). Material and Method: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesio-distal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of $\times100$. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. Results and Conclusion: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia$(81.9{\mu}m)$ and metal $(81.3{\mu}m)$ framework and internal marginal gaps of zirconia $(44.6{\mu}m)$ were smaller than those of metal framework $(58.6{\mu}m)$. 2. Internal axial gaps of zirconia framework$(96.7{\mu}m)$ were larger than those of metal frame-work$(78.1{\mu}m)$ significantly and adversely, internal occlusal gaps of zirconia frame-work$(89.4{\mu}m)$ were smaller than those of metal framework $(104.9{\mu}m)$ significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.