• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.297-302
• /
• 2007

Vibrating test of vehicle component can be possible in lab-based simulators instead of field testing owing to the development of technology in control algorithm as well as computational process. Currently, Multi-Axial Simulation Table(MAST) is recommended as a vibrating equipment, which excites a target component for 3-directional translation and rotation motion simultaneously and hence, vibrational condition can be fully approximated to that of real road test. But, the vibration-free performance of target component is not guaranteed with MAST system, which is only simulator subjective to the operator. Rather, the reliability of multi-axial vibration test is dependent on the quality of input profile which should cover the required severity of vibrating condition on target component. In this paper, multi-axial vibration testing methodology of vehicle component is presented here, from data acquisition of vehicle accelerations to the obtaining the input profile of MAST using severe data at proving ground. To compare the severity of vibration condition, between real road test and proving ground one, energy principle of equivalent damage is proposed to calculate energy matrices of acceleration data and then, it is determined the optimal combination of special events on proving ground which is equivalent to real road test at the aspects of vibration fatigue using sequential searching optimal algorithm. To explain the vibration methodology clearly, seat and door component of vehicle are selected as a example.

• 한국소음진동공학회논문집
• /
• 제24권2호
• /
• pp.123-130
• /
• 2014

An ultrasonic magnetostrictive transducer-based phased-array system for imaging defects in plate structures is newly proposed. In that most ultrasonic phased array systems rely on piezoelectric transducers or electromagnetic acoustic transducers, this system has its own unique feature of employing magnetostrictive transducers. Interest in using a phased array system using magnetostrictive transducers has been recently reported for pipe inspection but no such system has been developed for plate inspection. In this investigation, we aim to propose a phased array system using OL-MPTs (Omnidirectional Lamb wave Magnetostrictive Patch Transducers) for plate inspection. The developed system consists of a multi-channel function generator, power amplifiers, preamplifiers and a data acquisition unit. In the process of its development, each of the units must be checked and in doing so, we suggest types of ultrasonic wave experiments that should be carried out. Finally, the phased system using a transducer array composed of eight OL-MPTs is newly configured and is applied for actual crack detection experiments.

• 품질경영학회지
• /
• 제46권3호
• /
• pp.497-508
• /
• 2018

Purpose: The purpose of this study is to research the revision efficiency of the referenced specifications/standards for raw and subsidiary materials in the field of national defense. Methods: Firstly, it was carried out to investigate the all of the Korean military drawings and establish the database for specifications/standards referenced in the field of national defense. Secondly, it was reviewed the validity of referenced specifications/standards of raw and subsidiary materials. Finally, proposal documents were made for invalid referenced specifications/standards of raw and subsidiary materials in order to suggest alternative specifications/standards. Results: All of the specifications/standards referenced in the Korean military drawings were 11,924 kinds and raw and subsidiary specifications/standards were 2,711 kinds. The proposal documents for revision of invalid referenced specifications/standards were suggested and approved by the military procurement standardization committee of DAPA (Defense Acquisition Program Administration). Therefore, the revision process of 472 kinds of referenced specifications/standards and 160,177 papers of the Korean military drawings were finished. Conclusion: Based on the results of this investigation, it could be significantly reduce to administrative costs and efforts through revision of referenced specifications/standards instead of conventional engineering change.

• 한국근적외분광분석학회:학술대회논문집
• /
• 한국근적외분광분석학회 2001년도 NIR-2001
• /
• pp.1171-1171
• /
• 2001

Quantitative analysis is an important requirement in exploration, mining and processing of minerals. There is an increasing need for the use of quantitative mineralogical data to assist with bore hole logging, deposit delineation, grade control, feed to processing plants and monitoring of solid process residues. Quantitative analysis using X-Ray Powder Diffraction (XRD) requires fine grinding and the addition of a reference material, or the application of Rietveld analysis to XRD patterns to provide accurate analysis of the suite of minerals present. Whilst accurate quantitative data can be obtained in this manner, the method is time consuming and limited to the laboratory. Mid infrared when combined with multivariant analysis has also been used for quantitative analysis. However, factors such as the absorption coefficients and refractive index of the minerals requires special sample preparation and dilution in a dispersive medium, such as KBr to minimize distortion of spectral features. In contrast, the lower intensity of the overtones and combinations of the fundamental vibrations in the near infrared allow direct measurement of virtually any solid without special sample preparation or dilution. Thus Near Infrared Spectroscopy (NIR) has found application for quantitative on-line/in line analysis and control in a range of processing applications which include, moisture control in clay and textile processing, fermentation processes, wheat analysis, gasoline analysis and chemicals and polymers. It is developing rapidly in the mineral exploration industry and has been underpinned by the development of portable NIR spectrometers and spectral libraries of a wide range of minerals. For example, iron ores have been identified and characterized in terms of the individual mineral components using field spectrometers. Data acquisition time of NIR field instruments is of the order of seconds and sample preparation is minimal. Consequently these types of spectrometers have great potential for in-line or on-line application in the minerals industry. To demonstrate the applicability of NIR field spectroscopy for quantitative analysis of minerals, a specific example on the quantification of lateritic bauxites will be presented. It has been shown that the application of Partial Least Squares regression analysis (PLS) to the NIR spectra can be used to quantify chemistry and mineralogy in a range of lateritic bauxites. Important, issues such as sampling, precision, repeatability, and replication which influence the results will be discussed.

• The Plant Pathology Journal
• /
• 제26권1호
• /
• pp.37-48
• /
• 2010

This paper describes a web-based information system for plant disease forecast that was developed for crop growers in Gyeonggi-do, Korea. The system generates hourly or daily warnings at the spatial resolution of $240\;m{\times}240\;m$ based on weather data. The system consists of four components including weather data acquisition system, job process system, data storage system, and web service system. The spatial resolution of disease forecast is high enough to estimate daily or hourly infection risks of individual farms, so that farmers can use the forecast information practically in determining if and when fungicides are to be sprayed to control diseases. Currently, forecasting models for blast, sheath blight, and grain rot of rice, and scab and rust of pear are available for the system. As for the spatial interpolation of weather data, the interpolated temperature and relative humidity showed high accuracy as compared with the observed data at the same locations. However, the spatial interpolation of rainfall and leaf wetness events needs to be improved. For rice blast forecasting, 44.5% of infection warnings based on the observed weather data were correctly estimated when the disease forecast was made based on the interpolated weather data. The low accuracy in disease forecast based on the interpolated weather data was mainly due to the failure in estimating leaf wetness events.

• 한국환경과학회지
• /
• 제17권11호
• /
• pp.1227-1233
• /
• 2008

The effect of freeze drying and fixatives in post-treating freeze drying on the morphological properties of the rose (Rosa hybrida L.) petal were investigated for the production of high quality of freeze dried rose. The morphology including form and color of the dried flowers of cut rose were depended on the drying methods. The drying time was extended due to their density and water content, and was shorter in the freeze drying than that in the natural and hot air drying. Freeze dried process for dried flowers took 2 days in a freeze dryer and did not cause shrinkage or toughening of rose petal being dried, preserving its natural shape and color. The diameter of freeze dried flowers showed little reduction compared to fresh flowers. In Hunter color values of petals of freeze dried flowers, L and a values were high and showed little variations in comparison to fresh petals. Freeze drying led to a noticeable increase in anthocyanin contents in petals, suggesting that anthocyanin contents play an important role in the acquisition of freezing tolerance. Exposure of flowers to freeze drying was accompanied by an increase in the carotenoid content. In the post-treating freeze drying, epoxy resin, a fixative, applied alone or in combination to petals of freeze dried flowers showed efficient coating for the protection from humidity and sunlight. Combined application of epoxy and acetone to freeze dried petals permitted maintenance of natural color and excellent tissue morphology, showing color stability and shiny texture in surface of petals. These findings suggest that application of fixatives to freeze dried rose petals improves the floral preservation and epoxy coating provides good quality in the freeze dried flower product.

• 한국정보통신학회논문지
• /
• 제15권7호
• /
• pp.1583-1590
• /
• 2011

기존 방사선 검색장치는 2차원 방사선 스캔 영상을 사용하기 때문에 정확성이 낮다는 것이 문제점으로 지적되어왔다. 본 연구에서는 컨테이터 X-선 검색 영상에 대한 스테레오 영상처리 기술의 적용 가능성을 분석하였다. 일반적 방사선 검색장치에 라인 센서 하나만을 추가하여 새롭게 고안한 스테레오 영상획득 장치로부터 검사 오브젝트의 좌우 시차 정보를 달리하는 두 장의 이차원 방사선 스캔영상을 획득하였다. 획득 영상에 대해서 매칭 알고리즘을 이용하여 3차원 오브젝트 복원하는 과정을 진행하였다. 오브젝트의 투과밀도 정보인 방사선 영상의 특성상 일반 스테레오 영상처리 알고리즘 적용은 한계가 발생하였다. 이를 극복하기 위해 먼저 이차원 영상의 에지정보에 기반한 3차원 영상복원을 시도하였다. 또한 새로운 볼륨복원 방식의 3차원 복원 알고리즘을 제안하였고, 실험을 통해 오브젝트 검색에서 개선된 형상복원 방법임을 확인하였다. 제안된 기술은 제한된 스캔환경에서 CT나 MRI 적용이 어려운 오브젝트에 대해 응용이 가능할 것이다.

• 한국정보통신학회논문지
• /
• 제14권11호
• /
• pp.2435-2441
• /
• 2010

본 논문에서는 M2M 기반의 글로벌 헬스케어 모니터링 시스템을 구축하여 헬스케어 분야에 있어 기존의 센서네트워크의 확장성과 이동성을 보완하여 더욱더 안정적이고 신뢰성 있는 건강상태 정보를 제공하고자 하였다. 센서 노드는 웨어러블 심전도 및 맥파 센서와 결합되어 있으며, 각각의 생체신호를 수집하여 IEEE 802.15.4 표준 프로토콜과 6LoWPAN 프로토콜을 통해 외부 인터넷 망을 거쳐 서버로 전송한다. 또한 서버 프로그램은 측정된 생체신호를 통해 HRV 신호를 검출하였으며, HRV 신호를 이용한 시간 영역 및 주파수 영역 분석을 통해 환자의 스트레스 상태를 판단하도록 하였다. 이로써 제안된 시스템은 기존의 네트워크 인프라를 최대한 활용할 수 있는 장점을 가지고 있으며, 각각의 센서노드에 IP를 부여하여 헬스케어 서비스의 적용범위가 좁은 지역을 벗어나 범국가적으로 확대될 수 있도록 하였다.

• 한국정보통신학회논문지
• /
• 제21권7호
• /
• pp.1342-1348
• /
• 2017

디지털 정보화 시대에서 영상은 여러 매체에서 필수적으로 이용되며, 잡음은 이러한 영상을 획득, 전송하는 과정에서 여러 외부 원인에 의해 발생된다. 잡음 제거는 영상 처리에서 필수적인 과정이며, 잡음의 종류에는 발생 원인과 형태에 따라 다양한 종류가 있으며 AWGN이 대표적이다. 따라서 본 논문에서는 영상에 첨가된 잡음의 영향을 완화하기 위해, 전처리 과정으로 국부 마스크를 9개의 영역으로 구분하여 각 화소들의 평균을 이용한 에지 검출 방법을 적용한다. 그리고 변형된 에지 검출의 결과에 임계값을 적용하여 국부 마스크에 서로 다른 필터를 적용하는 알고리즘을 제안하였다. 제안한 알고리즘의 우수성을 입증하기 위해, 확대 영상 및 PSNR(peak signal to noise ratio)을 이용하여 기존의 방법들과 그 성능을 비교하였다.

• 한국정보통신학회논문지
• /
• 제19권4호
• /
• pp.965-972
• /
• 2015

현재 디지털 시대의 급속 발전과 함께 영상 매체는 인터넷, 컴퓨터, 디지털 카메라 등에 활용되고 있다. 그러나 디지털 영상을 획득, 처리, 전송, 기록하는 과정에서 여러 외부 원인에 의해 영상의 열화가 발생되며, 영상 열화의 주된 원인은 잡음에 의한 것으로 알려져 있다. 따라서 본 논문에서는 salt & pepper 잡음을 제거하기 위해 잡음 판단 후, 비잡음인 경우 원 화소로 대치하고, 잡음인 경우 Lagrange 보간법으로 처리하는 알고리즘을 제안하였다. 고밀도 잡음이 첨가되어 잡음제거가 불가능한 경우, 반복 처리하여 잡음 제거 특성을 향상시켰다. 그리고 객관적 판단을 위해 기존의 방법들과 비교하였으며, 판단의 기준으로 PSNR(peak signal to noise ratio)을 사용하였다.