• 물과 미래
• /
• 제29권2호
• /
• pp.129-141
• /
• 1996

일점연속 채취, 멱 속도 분포 및 Laursen의 토사농도 분포식을 이용한 총 부유 유사량 계산방법을 제안하였다. 이 방법은 미국 리오그안데 강에서 채취한 자료에 의해 검증되었다. 이 방법으로 계산된 농도분포는 $\beta$, $\kappa$, 그리고 w의 보편적인 값을 사용하여 계산한 보정 전수심 채취방법과 잘 일치하였다. 지역특성에 맞는 농도와 속도 분포식의 계수 x 와 z를 사용하였을 때는 더 좋은 결과를 얻을 수 있었다. 일점 채취에 사용한 이 방법과 일반적으로 많이 쓰는 전수심 채취를 사용한 방법과의 총 유사량의 차이는 채취때 생길 수 있는 오류 정도로 작은 것이었다. 일점 연속 채취에 의한 총 부유 유사량 측정은 여러 가지 중요한 이점을 가지고 있다. 채취 시간에 및 비용을 절감할 수 있으며 채취를 자주 할 수 있고 유사량 변화에 신속하게 대응할 수 명실상부 또한 이 방법은 미래에 추구해야 할 자동채취 방법으로 사용될 수 있다.

• 한국생산제조학회지
• /
• 제9권3호
• /
• pp.130-135
• /
• 2000

In this study the vibration behavior of the stiffened double cylinder was experimently analyzed. Due to the complex structure of the double cylinder the outside cylinder frequency responses to the exciting forces applied on various posi-tions were analyzed by using spectrum analyzer in conjunction with an accelerometer and the natural frequencies were obtained. The technique of time-averaged holographic interferometry is applied to study the vibration characteristics of outside cylinder with stiffening T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. however the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame. The experimental data showed that the T frame had salient effect of damping on the testing structure at most of resonances. However the experimental results also revealed interesting phenomenon. At some particular frequencies the T frame seemed to behave as a transmitter. In addition it has been successfully demon-started that optical method such as holographic interferometry is well suited for the identification of mode shapes. They can give us a whole-field non-contact measurement instead of the point-wise measurement by accelerometer in classical modal testing.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2000년도 춘계학술대회 논문집(Proceeding of the KOSME 2000 Spring Annual Meeting)
• /
• pp.153-158
• /
• 2000

Flow visualization and PIV measurements were conducted to investigate the flow characteristics of multi-channel with inclination angle. The water flow seeded with tiny vegetable powder as tracers revealed details of flow field. The PIV measurement to acquire multi-point velocity data simulatneously was carried out at three space of plates for 5, 10, and 15mm with variation of inlet flow rates of $0.25m^3/h$ and <$0.5m^3/h.$ Experiment results show that space of plates acts a significant role in separating process.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
• /
• pp.541-546
• /
• 1989

In case there are many points to be measured in the field, conventional measuring system requires a lot of manpower and is liable to miss applying the timely countermeasure because processing and analyzing the data obtained also takes much time. Therefore the purpose of this paper is focused on removing the above defects by introducing automatic multi-point measuring system by use of IBM-PC or the compatibles easily at hand nowadays. Principal components of the system is composed of control box, A/D converter. 32 channel 4 wire switch boxes and strain amplifier. An application software was developed for multi point measurement system in order to efficiently evaluate the stability of the structures such as retaining walls.

• Current Optics and Photonics
• /
• 제6권4호
• /
• pp.392-399
• /
• 2022

Light-measuring devices (LMDs) are frequently used to measure luminance and color coordinates of displays. However, it is very difficult to use a conventional LMD for measuring the optical properties of virtual-reality (VR) devices with a wide field of view (FOV), because of their confined spaces where the entrance pupil of a LMD is located. In this paper, a new LMD that can measure the optical properties of wide-FOV VR devices, without physical conflict with the goggles of the VR device, is proposed. The LMD is designed to fully satisfy the requirements of IEC 63145-20-10, and a pivot-point correction method for the LMD is applied to improve its accuracy. To show the feasibility of the developed LMD and the correction method, seven VR devices with wide FOV are measured with it. From the results, all of them are successfully measured without any physical conflict, and a comparison to their nominal values shows that the FOVs have been properly measured.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2001년도 학술논문발표회
• /
• pp.14-21
• /
• 2001

Recently, with the increasing of construction works, large construction equipment are used to reduce the term of work and labor cost in construction field. Therefore, construction equipment noise has caused much annoyance for a number of dweller in nearby construction field and it has become a very serious problem in our living environment. Nevertheless, in our country, adequite guidelines for the construction equipment noise are very deficiency because of the lack of basic data and insufficient research works. From this point of view, this study attempts to survey the characteristics and prediction of SIP piling noise. On the basis of measurement value, we analysed about prediction possibility of SIP piling noise by computer simulation.

• The Korean Journal of Ceramics
• /
• 제5권4호
• /
• pp.386-389
• /
• 1999

Effect of high voltage screening was examined on mechanical strength of titania ceramics with two different surface roughness. Roughly finished sample showed degraded mechanical strength meaning that the introduced flaw played the role of starting point of mechanical fracture. On such sample, electrically weak parts were eliminated by applying a screening field. Mechanical strength measurement on survived parts revealed that after screening the Weibull plots bended to become a convex curve while plots at high strength region were almost the same. This result means that relatively low mechanical strength parts were eliminated by the electrical method. As a result the Weibull modulus calculated from all the data increased, demonstrating the effect of high voltage screening on titania ceramics containing fracture controlling surface flaws. Roles of the surface flaw such as a common weak spot for both failures are disscussed in relation to the electric field concentration similar to that of mechanical stress.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.102-107
• /
• 2001

Recently, with the increasing of construction works, large construction equipment are used to reduce the term of work and labor cost in construction field. Therefore, construction equipment noise has caused much annoyance for a number of dweller in nearby construction field and it has become a very serious problem in our living environment. Neverthless, in our country, adequite guidelines for the construction equipment noise are very deficiency because of the lack of basic data and insufficient research works. From this point of view, this study attempts to survey the characteristics and prediction of piling noise in oil pressure method. On the basis of measurement value, we analysed about prediction possibility of piling noise in oil pressure method.

• 한국환경과학회지
• /
• 제4권5호
• /
• pp.427-435
• /
• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There's a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07m3m-3 for sand, 0.l1m3m-3 for loam, 0.12 for clay, and 0.13m3m-3 for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)'s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter. Key words : SMAP(Surface Moisture Availability Parameter), Paddy field, Volumetric soil water content, Evaporation, Capillary potential.

• 한국해안·해양공학회논문집
• /
• 제34권6호
• /
• pp.198-210
• /
• 2022

제주 남부 해협은 대마난류의 분기점으로써 한반도 해역 열염순환의 시작점이 되고 태풍, 쓰나미와 같은 해양 재해의 크기와 빈도에 영향을 미치며 유해생물이나 방사능 오염수가 들어오는 공급원이 되는 등 해양지리학적으로 매우 중요한 영향을 미친다. 따라서 이러한 해상재해 및 재난에 대하여 즉각적인 대응을 위해서는 준 실시간의 해양 관측이 필요하다. 그러나 다른 해협에 비하여 제주 남부의 경우 이러한 해상관측이 부족하며 이로 인해 연구결과 또한 저조한 실정이다. 따라서 본 연구에서는 제주 북부에서의 고주파 레이더 설치 경험을 활용하여 제주 남부에서 레이더 관측에 적합한 지역을 산정하고 고주파 레이더를 설치하여 관측을 진행하였다. 이를 통해 제주 남부해협의 광역 표층해류장을 산출하고 APM(Antenna Pattern Measurement)과 FOL(First Order Line)을 통한 후처리 및 자료 개선을 진행하였으며 이에 대해 실측자료를 활용한 비교분석을 진행하였다. 그 결과 상관계수에서 0.4~0.7, RMSE(Root Mean Square Error) 약 1~19 cm/s의 개선 결과를 보였다. 이러한 고주파레이더 관측결과는 자료 개방 네트워크 구축을 통해 차후에 태풍 대응, 수치모델 검증, 광역 파랑자료의 활용, 해양 수색 구조와 같은 국내 현안 문제를 해결하는데 도움을 줄 것이다.