• 한국구조물진단유지관리공학회 논문집
• /
• 제12권5호
• /
• pp.109-115
• /
• 2008

구조물이 초고층화, 대형화 되어감에 따라 철근의 이음방법에 대한 필요성이 증대되고 있다. 현재 일반적으로 건설현장에서는 겹이음을 많이 사용하고 있으나 굵은 직경을 사용한 구조부재의 경우 겹이음 사용 시 피복두께 확보의 어려움으로 부착파괴 및 접합부의 복잡한 배근으로 인한 콘크리트 타설의 시공성 저하 등이 문제가 되고 있다. 또한 압접이음은 철근의 단부를 국부적으로 가열하여 접합하는 방식으로 압접 후 철근의 취약부분이 발생할 수 있으므로 시공현장에서의 철저한 품질관리가 요구되는 단점이 있다. 이러한 단점을 해결하고자 새로운 개념의 Up-set Coupler를 적용하였다. 본 연구에서는 기계적 이음방법 중 철근 선조립공법이나 고강도, 대직경의 철근을 사용하는 PSC구조물의 접합부에서 주로 사용되는 대표적인 이음방법인 Screw Coupler와 Up-set Coupler, 그리고 이음이 없는 철근을 사용하여 각각의 인장특성과 사용성을 실험적으로 연구하고자 한다.

• Journal of Advanced Marine Engineering and Technology
• /
• 제36권8호
• /
• pp.1136-1142
• /
• 2012

신재생에너지의 관심이 증가함에 따라 해상풍력발전시장이 확대되고 있다. 열악한 환경에서 해상풍력발전을 안전하게 설치하기 위해서는 jack-up rig를 이용한 작업이 이루어져야하며, 최근에는 기존 jack-up rig의 단점을 보완한 자체추진력을 가진 WTIV가 개발되었다. 이는 60 m이하의 연안에서 주로 작업이 이루어지며, 이러한 지역은 연약 점성토 및 사질토로 jack-up rig 작업 시 지반침하에 대한 안정성 검토가 선행되어야 한다. 본 연구에서는 압밀이론을 고려하여 jack-up rig 작업이 연약지반에 미치는 영향을 FLAC3D를 이용하여 수치해석적인 연구를 진행하였다. 침하정도를 분석하고, 안정적인 jack-up rig 작업을 위해 재하방법을 달리하였다. 본 연구에서 적용한 차등재하방법 중 mid-loading 방법은 clay층에 유리하며, pre-loading 방법은 sand층에 유리한 결과가 나타났다.

• 한국통신학회논문지
• /
• 제39C권8호
• /
• pp.626-636
• /
• 2014

기존의 매쉬업 서비스는 개발자 위주로 제작되어 모든 사용자의 취향과 목적에 맞춰 제공할 수 없기 때문에 사용자가 자동으로 매쉬업 서비스를 제작할 수 있는 방법에 대한 연구가 진행되었다. 자동 매쉬업 서비스를 제공하기 위해서는 매쉬업이 가능한 요소를 선별하는 방법이 핵심 연구이며 선행 연구에서는 REST 기반 Open API의 입출력 파라미터 이름으로 유사도를 비교하는 방법을 사용하였다. 하지만 유사도 비교만 이용하여 매쉬업 가능성을 판별할 경우에는 입출력 파라미터의 특성을 고려하지 못하기 때문에 의도하지 않은 결과의 출력이나 매쉬업이 불가능한 경우가 존재하였다. 본 논문에서는 잘못된 매쉬업의 결과를 줄일 수 있는 방법으로 입출력 파라미터의 특성을 고려하는 방안에 대해 제시하고 이를 선행 연구에서 제안한 온톨로지에 적용하여 확장하였다. 또한 확장된 온톨로지를 기반으로 매쉬업이 가능한 요소를 판별하는 알고리즘을 제안하고 자동 매쉬업 서비스의 구현 결과를 보였다.

• 한국항공운항학회지
• /
• 제19권4호
• /
• pp.51-57
• /
• 2011

The spin-up and the spring-back are most severe load cases in the aircraft landing gear design. These load cases are caused by reciprocal action of complex physical phenomenon such as the friction between a tire and ground, inertia of the rotation of a tire and the flexibility of a landing gear structure. Generally, the empirical formula or the theoretical formula is used to calculate the spin-up and spring-back load in the early stage of the development program of the aircraft landing gear. After the materialization of the design of a landing gear, spin-up and spring-back load are acquired by the free drop test. In this study, the spin-up and the spring-back load of the rubber shock absorber type KC-100 nose landing gear are calculated by the explicit finite element analysis. Through this analysis, more accurate and realistic spin-up and spring back loads could be applied to the early phase of the development of the aircraft landing gear.

• 한국조경학회지
• /
• 제21권4호
• /
• pp.29-41
• /
• 1994

The purposes of this study are (a)to investigate the effect of follow-up on the increase of response rate;(b)to analyze the effect of follow-up on the statistics by predetermined response rates ; therefore, (c)to describe the importance of high response rate and to suggest methods in order to increase response rate in mail survey. Telephone directory of Seoul was utilized as a sampling frame, and modified Total Design Method(TDM) was applied to collect the data. The results are summarized as follows. 1. Final response rate was 76.5% by 2 follow-ups. 2. The first follow-up with telephone call had a significant effect on increase of response rate. As a result, follow-up by postcard in TDM could be omitted in this method. 3. The second follow-up by registered mail did not have a significant effect. Therefore, use of this procedure is depending upon such research situtations as importance of high response rate and cost available. 4. Follow-ups helped to make collected sample highly representative. 5. Most questionnaires were arrived on the first half of data collection period in each follow-up. 6. Most of questionnaires were collected for 10 weeks. Accumulated responses could be fitted by exponential and logistic curve, simultaneously. The fitted curve suggested that eventually limited number of questionnaires by arrived. So, if researchers want higher response rate, they have to conduct more follow-ups. 7. Statistics in the predetermined response rate were not changed significantly. But replications are needed to generalize this result.

• 로봇학회논문지
• /
• 제16권1호
• /
• pp.56-63
• /
• 2021

As the use of robots in service area increases, research has been conducted to replace human tasks in daily life with robots. Among them, this study focuses on the tidy-up task on a desk using a robot arm. The order in which tidy-up motions are carried out has a great impact on the success rate of the task. Therefore, in this study, a neural network-based method for determining the priority of the tidy-up motions from the input image is proposed. Reinforcement learning, which shows good performance in the sequential decision-making process, is used to train such a task planner. The training process is conducted in a virtual tidy-up environment that is configured the same as the actual tidy-up environment. To transfer the learning results in the virtual environment to the actual environment, the input image is preprocessed into a segmented image. In addition, the use of a neural network that excludes unnecessary tidy-up motions from the priority during the tidy-up operation increases the success rate of the task planner. Experiments were conducted in the real world to verify the proposed task planning method.

• Nuclear Engineering and Technology
• /
• 제55권12호
• /
• pp.4350-4356
• /
• 2023

Radiation detection systems working at high count rates suffer from the overlapping of their output electric pulses, known as pulse pile-up phenomenon, resulting in spectrum distortion and degradation of the energy resolution. Pulse tail extrapolation is a pile-up correction method which tries to restore the shifted baseline of a piled-up pulse by extrapolating the overlapped part of its preceding pulse. This needs a mathematical model which is almost always nonlinear, fitted usually by a nonlinear least squares (NLS) technique. NLS is an iterative, potentially time-consuming method. The main idea of the present study is to replace the NLS technique by an integration-based non-iterative method (NIM) for pulse tail extrapolation by an exponential model. The idea of linear extrapolation, as another non-iterative method, is also investigated. Analysis of experimental data of a NaI(Tl) radiation detector shows that the proposed non-iterative method is able to provide a corrected spectrum quite similar with the NLS method, with a dramatically reduced computation time and complexity of the algorithm. The linear extrapolation approach suffers from a poor energy resolution and throughput rate in comparison with NIM and NLS techniques, but provides the shortest computation time.

• 전자공학회논문지
• /
• 제50권8호
• /
• pp.162-167
• /
• 2013

X-선과, ${\gamma}$-선을 이용한 형광분석장치는 현재 널리 쓰이는 물질의 고유특성을 분석하는 장치이다. 하지만 여러 가지 원인으로 인해 장치사용 시 측정 신호에서 중첩 현상이 발생한다. 검출 신호의 높이는 측정 물질의 특성을 반영하며 측정 물질을 정확히 분석하기 위해서는 중첩된 신호를 제거하거나 복원을 해야 한다. 현재 trapezoidal 필터는 형광분석장치에 널리 사용되고 있으며 중첩펄스 검출에서도 좋은 결과를 보이고 있다. 본 논문에서는 측정 신호의 사다리꼴 변형에 기반 한 중첩펄스 처리방법을 제안한다. 제안방법은 사다리꼴 필터를 이용한 최대값 검출 알고리즘에 두 개의 카운터와 몇 개의 레지스터만을 추가하여 추가적인 중첩펄스 처리 알고리즘을 구현하기 때문에 기존 방법에 비해 하드웨어 복잡도가 훨씬 적으면서도 정확히 중첩펄스를 처리 할 수 있다.

• 대한후두음성언어의학회지
• /
• 제18권1호
• /
• pp.26-32
• /
• 2007

Objective and Background: Laryngeal stroboscope is an useful equipment in evaluation of vocal cord vibration and in early detection of mucosal lesion including invasive cancer of the vocal cord. Recently Lee et al. (2006) developed portable stroboscope using voice as synchronization signal. It has been frequently impaired ability to synchronize the flashes even in normal female. Authors tried to investigate various methods including vibration pick-up, microphone, laryngeal microphone, and contact microphone for development of simple and accurate method like electroglottograph signal. The purpose of this study was to estimate wheher the vibration pick-up is available and is consistent with the signal of EGG. Subjects and Methods: Authors compared the signals between EGG and noncontact method such as voice, contact methods including vibration pick-up, laryngeal microphone, and contact microphone in normal twenty adults (male 10 and female 10). The number of peak in one cycle was compared with the number of the peak in EGG, and the percent of phase difference in the peak was compared with EGG Also, authors tried to investigate which site of vibration pick-up was most effective for synchronization of stobo flashes. Three site including anterior neck below the cricoid cartilage, thyroid ala, and suprahyoid region were analysed. Results: Among various methods for synchronization of strobo flashes, vibration pick-up was most effective method in peak detection. And anterior neck below cricoid cartilage was the most available site of the vibration pick-up. Conclusion: Authors suggest that vibration pick-up is most available and effective method for synchronization of strobo flashes.

• 한국의류학회지
• /
• 제28권2호
• /
• pp.332-343
• /
• 2004

This is a study on expression and the extent of using make-up according to the lifestyle of woman. The purpose of this study is to induce factors which decide the lifestyle of woman, group them, understand groups＇ demographic characteristic and study on make-up expression and the extent of using make-up according to the lifestyle of groups. This survey is conducted to 611 women and analyzed with SPSS package. The result of a study is as follows： 1. We classified them into 5 factors such as factors of make-up preference, arance-oriented, economy and information-oriented, daily make-up, and interest in make-up with the method of AIO analysis. Then I researched groups on the basis of the mean of those factors. As a result, it is classified as a make-up oriented group, a consciously daily make-up group, a unconcern of make-up group, and a reasonable make-up pursuit group. 2. The demographic characteristic according to the classified lifestyles showed the difference as a result of variance analysis of age, marital status, job, education, and monthly pay. 3. A result of variance analysis on the extent of satisfaction with their faces according to the lifestyle showed the difference of facial satisfaction with complexion, skin, eyes, nose and so on. 4. We analyzed a reason of make-up, a extent of make-up, image to express, the most concerning part for make-up, and the type of cosmetics which people use most in order to know the difference of make-up expression and the extent of using make-up. As a result, its variance showed the difference among groups.