• 한국정밀공학회지
• /
• 제18권10호
• /
• pp.200-207
• /
• 2001

Burrs farmed in drilling are classified into three types, no burr, burrs with cap, teared burr. To control burr size in drilling, the second type burrs with cap are to be formed because it is small and uniform. It is necessary to understand the mechanism of cap formation to derive the burr formation into second type burr with cap. In several materials. second type burrs are formed in drilling by changing cutting conditions. It is observed that cap is formed as a result of the plastic deformation along the outside of exit hope. According to the tension behavior of the material in concentrated region between hole and drill outside edge, the geometry of burr with cap is determined. Simplified 2D FEM analysis shows good prediction for burr formation.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 2002년도 하계학술발표대회 논문집 제21권 1호
• /
• pp.209-212
• /
• 2002

The wear process of end mill is a so complicated process that a more reliable technique is required for the monitoring and controling the tool life and its performance. This research presents a new tool wear monitoring method based on the sound signal generated on the machining. The experiment carried out continuous-side-milling for 4 cases using the high-speed steel slot drill under wet condition. The sound pressure was measured at 0.5m from the cutting zone by a dynamic microphone, and was analyzed at frequency domain. The tooth passing frequency appears as a harmonics form, and end mill wear is related with the first harmonic. It can be concluded from the result that the tool wear is correlate with the intensity of the measured sound at tooth passing frequency estimation of end mill wear using sound is possible through frequency analysis at tooth passing frequency under the given circumstances.

• 대한조선학회논문집
• /
• 제49권1호
• /
• pp.45-51
• /
• 2012

Sea ice properties have been considered a key indicator in the structural design criteria of icebreaking vessels and arctic offshore platforms to estimate design ice load and resistance for their safety management in Arctic Ocean. A measurement study of sea ice properties was conducted during July to August of 2011 with the Korean icebreaking research vessel "Araon" around Chukchi Borderland. The sea ice concentration appears to be rapidly decreasing during this cruise. Ice condition seems to be thick second-year ice and multi-year ice and then, a lot of melt ponds were observed in the surface of ice floe. Calculated flexural strength of sea ice was about 250~550kPa, ice thickness was roughly 1.3~3.0m. In this research we performed field experiment to measure ice temperature along the depth, thickness, density, salinity, brine volume ratio and crystal structure. Apparent conductivities derived with the electromagnetic induction instrument were compared to drill hole measurement results and accuracy of sea ice thickness estimation formula was discussed.

• 산업기술연구
• /
• 제29권B호
• /
• pp.57-64
• /
• 2009

This study has analysed actual overbreak, shotcrete rebound and the ratio between the actual quantity of shotcrete to designed shotcrete measured during a NATM tunnel construction. The measured shotcrete rebound was about 7.2% in average which was about half the allowable rebound (15%), showing shotcrete spraying was performed well. Based on the measurement of excavated tunnel shape, average overbreak was about 28.5cm after tunnel excavation by drill and blasting method. This was about 260% of allowable overbreak. In addition, due to the rebound and overbreak actual amount of shotcrete used in the tunnelling work was about 116.5 % of the designed value. According to the field measurement the ratio of actual shotcrete to designed value showed some relation with standard support pattern, but the size of overbreak did not show the correlation with standard support pattern. Hence current design specifications stating the size of overbreak based entirely on standard support pattern should perhaps be reestablished. The insight into the design guideline regarding overbreak and shotcrete.

• 정보교육학회논문지
• /
• 제7권2호
• /
• pp.141-151
• /
• 2003

본 연구는 초등학교 저학년 아동들의 국어 읽기 능력의 신장 및 문자 해독 능력을 배양하기 위한 입문기 문자 지도용 멀티미디어 프로그램을 설계 및 구현하는 데 그 목적이 있다. 이에 따라 본 연구에서는 기본 음절표 및 쓰기 시범 자료와 표준 발음을 포함한 학습 내용으로 재구성하여 입문기 문자 지도에서 요구되는 반복 연습 및 개별 학습의 기회를 제공하여 아동들이 자신감을 가지고 접근할 수 있는 멀티미디어 프로그램을 개발하고자 하였다. 본 프로그램은 낱자 공부, 낱말 공부, 바르게 쓰기 등의 기본 학습 내용과 동화 읽기, 쉼터 등의 심화 학습 내용 및 숨은 그림 찾기, 낱자 끌어다 놓기, 배운 것 알아보기 등의 평가 내용으로 구성되어 있으며, 실제 교육 현장에서의 활용 가능성 및 기대 효과를 제시하였다.

• 한국소음진동공학회논문집
• /
• 제20권12호
• /
• pp.1210-1215
• /
• 2010

Unit cabin means room, which is installed in the high value-added vessel such as drill ship, offshore platform and FPSO, after pre-assembled. In order to develop the noise control design for a unit cabin, a variety of acoustic tests such as sound absorption, transmission and radiation measurements were carried out by using the deckhouse mock-up. From the tests, it was found out that the sound transmission loss between cabin and corridor was 13 dB below than FPSO standard and the combined noise level of the unit cabin was dominated by the radiated noise from wall panel in low frequency range. Based on the test results, design guidelines for the noise control of the unit cabin were fully established, such as the improvement of sound transmission loss between the cabin and corridor, and radiated cabin noise reduction.

• 터널과지하공간
• /
• 제6권3호
• /
• pp.197-208
• /
• 1996

Due to the constraints in pre site-investigation for tunnel, it is essential to redesign the support structures suitable for rock mass conditions such as rock strength, ground water and discontinuity conditions for safe tunnel construction. For the selection of optimum support, it is very important to carry out the rock mass classification and in-situ measurement in tunnelling. In this paper, in a mountain tunnel designed by NATM in hard rock, the selectable system for optimum support has been studied. The tunnel is situated at Chun-an in Kyungbu highspeed railway line with 2 lanes over a length of 4, 020 m and a diameter of 15 m. The tunnel was constructed by drill & blasting method and long bench cut method, designed five types of standard support patterns according to rock mass conditions. In this tunnel, face mapping based on image processing of tunnel face and rock mass classification by RMR carried out for the quantitative evaluation of the characteristics of rock mass and compared with rock mass classes in design. Also, in-situ measurement of convergence and crown settlement conducted about 30 m interval, assessed the stability of tunnel from the analysis of monitoring data. Through the results of rock mass classification and in-situ measurement in several sections, the design of supports were modified for the safe and economic tunnelling.

• 구강회복응용과학지
• /
• 제31권3호
• /
• pp.178-185
• /
• 2015

목적: 본 연구에서는 Simplant와 R2GATE 두 가지 수술용 가이드 시스템의 인터페이스(interface)에 대한 만족도, 제작된 수술용 가이드의 디자인과 편의성, 수술용 가이드 활용 시 중요도에 대한 만족도를 설문조사하여 비교평가 하고자 하였다. 연구 재료 및 방법: 두 가지 시스템으로 제작된 수술용 가이드(surgical guide)를 치아모형에 각각 장착한 상태에서 임플란트 수술 과정을 모의하였다. 모의 수술이 끝난 뒤 연구대상에게 만족도에 관한 설문지를 작성하도록 하였다. 작성된 설문지를 회수하여 각 문항에 대한 데이터를 정리하고 통계 프로그램 SPSS 20.0 (IBM)를 이용하여 분석하였다. 결과: 전체적인 만족도는 R2GATE 군($7.33{\pm}1.26$)이 SimPlant 군($6.67{\pm}1.26$)보다 더 높은 것으로 나타났다(${\alpha}$ = 0.05). 결론: R2GATE 시스템으로 제작된 수술용 가이드는 임상에 널리 사용 할 만 한 사용자의 만족도를 나타내었다. 또한, R2GATE 시스템으로 제작된 수술용 가이드는 drill의 길이와 방향을 동시에 guide할 수 있어 임플란트 식립 경험이 부족한 초심자에게 적극 추천된다.

• 한국콘텐츠학회논문지
• /
• 제17권3호
• /
• pp.222-230
• /
• 2017

국민안전처는 2016년 국민의 생활안전 기반 강화를 위한 정책으로 맞춤형 소방안전교육과 소방안전문화 확산을 위한 정책을 추진하고 맞춤형 소방안전 교육체제 마련을 위해 소방안전교육 인프라 확충을 위한 방안을 계획 중이다. 이는 그간 우리사회의 안전에 대한 문제점을 개선하기 위한 방안으로 본 연구가 선행되어진 이유이기도 하다. 현재 안전교육이 시행되고 있으나 실제현장과 같은 상황을 체험할 수 없고 교육에 대한 만족도도 기초적인 수준에 불과하다. 이에 이러한 문제를 해결하기 위한 효과적인 대안으로 VR 소방체험교육콘텐츠를 제안한다. 이는 가상공간에서 화재진압과 대피훈련에 대한 체험교육을 목적으로 1)소방체험교육현장에서 안전하게 활용 2)흥미유발을 위한 인터랙션 UI 제공 3)동작인식기술과 조작 컨트롤러를 개발 사실감 증대 4)예산절감의 경제적 효과를 기대할 수 있다. 이에 VR 디자인 환경요소와 VR 교육콘텐츠 개발사례를 통해 체험교육의 학습적 효과를 알아보고 UX 디자인방법론(Persona, Task Scenario)을 적용하여 VR 소방체험 시스템 구조와 하드웨어를 구성한다. 또한 HMD 환경에서 조작과 몰입 감을 유도할 수 있는 VR 전용 동작인식과 컨트롤러의 통합 플러그인도 개발한다.

• 한국의류학회지
• /
• 제31권1호
• /
• pp.1-10
• /
• 2007

This research was designed to compare the subjective evaluation of Hand between on- and off-line by structure and sensible characteristics of fabric. 113 subjects who have a fashion design major evaluated the subjective evaluation of Hand of various 16 kinds of specimens on- and off-line. T-test and pearson correlation coefficient were used for statistical analysis by SPSS WIN 11.0. The results of this study were as follows: The results of correlation analysis of the evaluation score indicated that Crash and Satin show high correlation between two kinds of evaluation score. But, fabrics which have distinct characteristics such as Plush, Dobby, Seersucker represented low correlation coefficient. The results of t-test fer the difference of the evaluation score showed that thin fabrics like Organdy represent a large difference between on- and off-line evaluation. On the other hand, twill weaved fabrics like Drill, Tweed, Saxony did not show many differences. Analysing each item in terms of correlation of evaluation of hand between on- and off-line gave results that the shininess was most deliverable through on-line and density and the dryness was not so deliverable through on-line. Comparison of evaluation score between on- and off-line items showed that the estimation to real fabric is more negative than that of on-line. The results of most preferable hand between on-and off-line showed exact opposite preference between shinny, smooth and soft Satin and rough, woolen Tweed. Organdy showed the most different subjective evaluation of hand in real ones compared with that of on-line.