• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.583-589
• /
• 2001

For several decades many researchers have studied various algorithms, known as non-destructive testing, to identify abnormalities within a structure. Damage detection technique using vibration signal is a kind of these methods. Many researchers have published lots of papers dealing vibration signal to identify structural damage. All the methods for damage detection using vibration signal can be divided into two big categories. The first category is the method that requires some reference model such as finite element model, and the second is the method that does not require any reference model but needs only experimental data. This paper will be devoted to classify damage detection methods that utilize vibration signal.

• 비파괴검사학회지
• /
• 제32권5호
• /
• pp.526-539
• /
• 2012

본 연구에서는 기존의 방광 내압 측정의 문제점을 근본적으로 해결할 수 있는 새로운 접근법인 '초음파를 이용한 비침습적 방광 내압 측정 기술'을 제안한다. 제안된 기술은 초음파에 의한 캐비테이션 현상을 이용한다. 즉, 체외에서 조사된 고강도 초음파 펄스에 의해 방광 내에 생성된 기포의 동 특성은 방광 내압에의 영향을 받는다는 물리적인 현상에 근거한다. 본 논문에서는 초음파 방광 내압의 측정 기술의 이론적 기초를 제시하고 및 초기적인 측정 실험을 통해 실현 가능성을 입증했다. 제안된 초음파 방광 압력 측정법은 비침습적이며, 성별, 연령에 관계없이 적용 가능하고, 상시 측정이 가능하여 향후 방광 및 배뇨 장애 관련 진단 및 치료에 크게 기여할 것으로 기대된다.

• Computers and Concrete
• /
• 제29권1호
• /
• pp.31-45
• /
• 2022

Experimental and numerical simulation were used to investigate the effects of angle and number of T shape non-persistent crack on the shear behaviour of crack's bridge area under uniaxial compressive test. concrete samples with dimension of 150 mm×150 mm×40 mm were prepared. Within the specimen, T shape non-persistent notches were provided. 16 different configuration systems were prepared for T shape non-persistent crack based on two and three cracks. In these configurations, the length of cracks were taken as 4 cm and 2 cm based on the cracks configuration systems. The angle of larger crack related to horizontal axis was 0°, 30°, 60° and 90°. Similar to cracks configuration systems in the experimental tests, 28 models with different T shape non-persistent crack angle were prepared in numerical model. The length of cracks were taken as 4 cm and 2 cm based on the cracks configuration systems. The angle of larger crack related to horizontal axis was 0°, 15°, 30°, 45°, 60°, 75° and 90°. Tensile strength of concrete was 1 MPa. The axial load was applied to the model. Displacement loading rate was controlled to 0.005 mm/s. Results indicated that the failure process was significantly controled by the T shape non-persistent crack angle and crack number. The compressive strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. Furthermore, it was shown that the compressive behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the crack number and crack angle. The strength of samples decreased by increasing the crack number. In addition, the failure pattern and failure strength are similar in both methods i.e. the experimental testing and the numerical simulation methods (PFC2D).

• 인지과학
• /
• 제11권1호
• /
• pp.33-45
• /
• 2000

본 연구는 정보 시스템으로서의 웹(WWW)의 인지심리학적 특성들을 고려하여 웹사이트의 사용성에 관련된 디자인 특성들을 밝히고자 하였다. 구체적으로 다양한 목적의 웹사이트를 선정하고 다양한 비실험적 방법들을 이용하여 그 사이트의 홈페이지 디자인에 관한 사용성 평가를 실시하였다. 이를 위해 연구 1에서는 설문조사법을 통한 웹사이트의 사용성을 조사하였다. 그 결과, 몇 가지 중요한 사용성과 관련된 디자인의 특성들 및 요인들이 추출되었다. 연구 2에서는 연구 1에서 쉽게 발견되지 않은 특정 웹사이트의 세부적 사용성 문제들을 검출하기 위해 발견적 평가를 실시하였다. 연구 2의 결과, 발견적 평가가 연구 1 의 설문조사에 비해 디자인의 세부적인 문제점들을 더 잘 드러내는 것으로 나타났다.

• The Journal of Korean Physical Therapy
• /
• 제26권5호
• /
• pp.344-350
• /
• 2014

Purpose: The purpose of this study was to translate and culturally adapt the International Classification of Functioning, Disability and Health (ICF) into the Korean language. Methods: The process of translation and adaptation of the ICF used here followed the translation guidelines of WHO. Implementation of this procedure comprised of four steps; forward translation, expert panel back-translation, pre-testing and cognitive interviewing, and final adaptation. The translators included health professionals with knowledge of ICF and non-health professionals blinded to the ICF. Clinical academics with significant experience in the use of disability survey, medical doctors, special educators, related policy makers, clinicians, architecture professionals, and international experts in ICF were invited to integrate all versions of the ICF for testing; 151 clinicians volunteered from 19 medical institutes across the country. Four different core-sets and a questionnaire were used for testing its practical usability and adaptation. Results: All translations were reviewed and a consensus was reached on any discrepancy from the earlier versions. Over 90% of the newly translated version of K-ICF was found to be different from the 2004 K-ICF version in the ICF language. Understanding of K-ICF language was responded difficult and very difficult by 50% of participants, whereas its practical use was responded 'useful' by more than 50% of subjects. Conclusion: It can be suggested that the new version of K-ICF should be widely used for final adaptation in the field of areas. Future studies will be required for implementation of K-ICF.

• 한국정밀공학회지
• /
• 제26권1호
• /
• pp.97-104
• /
• 2009

There is a many kinds with nondestructive testing such as RT and UT representatively. Referred before two testing methods there is a limit which is spatial such as nuclear pipe, small vessel, sealing up vessel. So a new technique needs to overcome the limit which is spatial. shearography will be able to overcome the limit which is spatial. This paper introducing shearography which was known as non-contact full-field testing method and It is an interferometric technique for measurement of surface deformation such as displacement or displacement gradient. Also, a research about internal defect of the flange welding zone was accomplished. About variation with method pressurized with the Gaseous Nitrogen. Phase map where is various were measured according to changing a sheared direction, size of crack and loaded pressure. Consequently, crack quantitatively to be detected qualitatively was measured by using shearography.

• 한국안전학회지
• /
• 제33권6호
• /
• pp.58-65
• /
• 2018

The life span of the porcelain insulator was made to be 30 years, but currently many of the 154kV NGK porcelain insulators using in Korea are found to have passed the production life. Accidents caused by aged mechanical breakdown can lead to disruption of power supply in some areas, large economic losses, and casualties. Therefore, ultrasonic method, which is one of the non - destructive test methods, is applied as a method for evaluating the integrity of porcelain insulators. In this study, the experiment on the interface of cap was conducted and the difference between the energy difference and the attenuation coefficient of the reflected wave was derived according to the interface state of the steel - cement. The results of this study are expected to be used as the basic data of the ultrasonic testing to evaluate the interface condition of the porcelain insulator cap.

• 대한건축학회논문집:구조계
• /
• 제34권3호
• /
• pp.43-52
• /
• 2018

This study is conducted to evaluate the performance of ceramic panels and painting materials for humidity control which are developed in non-plastic room temperature hardening structure as part of a project to improve a residential environment for the low-income class, rather than the performance of high-priced humidity control materials that are produced with the existing plasticity processing. The testing methods included the measurements of absorption & desoprtion of humidity per material; Mock-up Testing; an evaluation method of comparing the absorption & desoprtion performances of Ecocarat, ceramic panels and painting materials through Living Lab. According to the measurements of absorption & desoprtion per material, ceramic panels, E panel, and ceramic painting material showed 73.3g/m2, 96.6g/m2, and 111.1g/m2, respectively. That is, the performance of humidity control of each material was found to be good in the order of: Ceramic Paint > E panel > Ceramic Panel. According to performance evaluation testing with Mock-up test and Living Lab, Ceramic Paint, Ecocarat, and Ceramic Panels showed better absorption & desoprtion performances in the order.

• Current Optics and Photonics
• /
• 제8권2호
• /
• pp.127-137
• /
• 2024

The distribution of tags is an important factor that affects the performance of radio-frequency identification (RFID). To study RFID performance, it is necessary to obtain RFID tags' coordinates. However, the positioning method of RFID technology has large errors, and is easily affected by the environment. Therefore, a new method using optical measurement is proposed to achieve RFID performance analysis. First, due to the possibility of blurring during image acquisition, the paper derives a new image prior to removing blurring. A nonlocal means-based method for image deconvolution is proposed. Experimental results show that the PSNR and SSIM indicators of our algorithm are better than those of a learning deep convolutional neural network and fast total variation. Second, an RFID dynamic testing system based on photoelectric sensing technology is designed. The reading distance of RFID and the three-dimensional coordinates of the tags are obtained. Finally, deep learning is used to model the RFID reading distance and tag distribution. The error is 3.02%, which is better than other algorithms such as a particle-swarm optimization back-propagation neural network, an extreme learning machine, and a deep neural network. The paper proposes the use of optical methods to measure and collect RFID data, and to analyze and predict RFID performance. This provides a new method for testing RFID performance.

• 비파괴검사학회지
• /
• 제19권4호
• /
• pp.270-276
• /
• 1999

지금까지 퓨리에 변환이 신호처리법으로 가장 널리 사용되고 있다. 그러나, 이 방법은 신호의 주파수성분이 시간에 대하여 어떻게 변화하는지를 표현하지 못한다. 따라서, 최근 이와 같이 비정상신호를 표현하지 못하는 퓨리에 변환의 단점을 보완하여, 신호의 시간과 주파수에 대한 정보를 동시에 표현할 수 있는 시간-주파수 해석법들이 개발되기 시작하였다. 본 연구에서는 인공열화된 SUS 316강의 초음파신호를 시간-주파수 해석법으로 분석하였다. 특히, 단시간 퓨리에 변화법과 위그너 빌 분포법을 이용하여 초음파 신호의 주파수 성분과 특성을 분석하였다.