• 소음진동
• /
• 제2권3호
• /
• pp.181-192
• /
• 1992

A method of measuring the transmission loss of silencer using two microphone technique is described. Two microphone methol is used to elliminate the measurement error due to reflected wave spectra in inlet/outlet duct of silencer. Errors associated with the measurement method are studied. Henceforth the methods to effectively supress the influence are presented. Based on these considertions, the appropriate procedure of experimental set-up to measure the transmission loss a silencer is described with experimental verifications.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
• /
• pp.208-211
• /
• 2006

The contents of RF test set which can be used for checking the function and performance of 13m antenna installed in KARI site are described in this paper. For the purpose of considering RF test set as the transceiver in COMS, it is designed to retransmit the LRIT and HRIT in L-Band after receiving them in S-Band from 13m antenna. Additionally, this set has a function to turnaround raging tone used for the measurement of distance between satellite and 13m antenna. The required all equipments of RF test set are summarized with configuration. Measurements of several equipments which have already been delivered are described in this paper. The assembled RF test set will be used for the verification of 13m antenna

• Communications for Statistical Applications and Methods
• /
• 제13권2호
• /
• pp.419-428
• /
• 2006

The method of Reverse Ranked Ordering-Set Sampling(RROSS) as an opposed Ranked Ordering-Set Sampling(ROSS) and Ranked-Set Sampling(RSS) is discussed. We propose the test statistic using sign test on RROSS. This method is effective when observations are expensive and measurement is perhaps destructive or invasive. This method obtains more informations than ROSS and RSS. The asymptotic relative efficiencies of RROSS with respect to ROSS and RSS are always greater than 1 for all sample sizes. We consider a simple model to describe the effect of imperfect judgment errors.

• Current Optics and Photonics
• /
• 제7권4호
• /
• pp.378-386
• /
• 2023

A wideband instantaneous frequency measurement (IFM) system is been proposed, designed and analyzed. Phase modulation to intensity modulation conversion is implemented based on the stimulated Brillouin scattering (SBS) effect, and the microwave frequency can be measured by detecting the change in output power. Theoretical analysis shows that the frequency measurement range can be extended to 4f_b by adjusting the two sweeping signals of the phase modulators with a difference of 2f_b. The IFM system is set up using VPI transmission maker software and the performances are simulated and analyzed. The simulation results show that the measurement range is 0.5-45.96 GHz with a maximum measurement error of less than 9.9 MHz. The proposed IFM system has a wider measurement range than the existing SBS-based IFM system.

• 한국정밀공학회지
• /
• 제14권4호
• /
• pp.64-71
• /
• 1997

Objective of calibration is to find out the accurate kinematic relationships between robot joint angles and the position of the end-effector by estimating accurate model parameters defining the kinematic function. Estimating the model parameters requires measurement of the end-effector position at a number of different robot configurations. This paper studies the implication of measurement configurations in robot calibration. For selecting appropriate measurement configurations in robot calibration, an index is defined to measure the observability of the model parameters with respect to a set of robot configurations. It is found that, as the observability index of the selected measurement configurations increase the attribution of the position errors to the parameter errors becomes dominant while the effects of the measurement and unmodeled errors are less significant; consequently better estimation of parameter errors is expected. To demonstrate the implication of the observability measure in robot calibration, computer simulations are performed and their results are discussed.

• 경영과학
• /
• 제11권2호
• /
• pp.237-253
• /
• 1994

Technology measurement is related with how to construct indicators of technological change and relative ranking of technological sophistication. Many attempts have been made to understand the measurement of technology. However, technology measurement still remains little understood problem in spite of its importance. This article is concerned with improving the measurement of technology by introducing market factors into the model. It illustrate a simple approach to the measurement of technology. This approach is based on the characteristic-space paradigm of technology. A relative ranking of technological sophistication for a product is measurable as a set of characteristics. The main feature of the proposed approach is the combination of technical factors and market factors. Technical factors are reflected in the definition of technological sophistication. Market factors are embraced in the determination of the relative importance assigned to each technology defining characteristics. Thus, the weight is determined by technical factors and market factors, which differentiates the study from the past based on judgmental technique such as experts' opinion.

• 한국해양공학회지
• /
• 제12권2호통권28호
• /
• pp.121-129
• /
• 1998

A quantitative non-contact multi-point measurement system is proposed to the measurement of three-dimensional movement of floating vessels by using digital image processing. The instantaneous three-dimensional movement of a floating structure which is floating in a small water tank is measured by this system and its three-dimensional movement is reconstructed by the measurement results. The validity of this system is verified by position identification for spatially distributed known positional values of basic landmarks set for the camera calibration. It is expected that this system is applicable to the non-contact measurement for an unsteady physical phenomenon especially for the measurement of three-dimensional movement of floating vessels in the laboratory model test.

• 한국정밀공학회지
• /
• 제13권2호
• /
• pp.62-66
• /
• 1996

Since 1980, Korea Research Institute of Standards and Science (KRISS) have performed 8 round robin tests in gauge block measurement in order to evaluate the measurement capability and the state of environment control of National Calibration and Test Institutions. Two sets of five gauge blocks (nominal size : 1, 3, 10, 25, 100 mm) having different thermal expansion coefficients for each set were circulated for the measurement, and the measurement results were collected and analyzed to evaluate the traceability to the standard of KRISS. The method and results of the test are presented.

• 한국공작기계학회논문집
• /
• 제13권6호
• /
• pp.34-40
• /
• 2004

This paper presents studies on curvature radius measurement using the laser interferometer. It is a general practice to measure to $10^{-10}$m in length with the recent improvement and innovations in measurement technology and the processor used. The measurement methods can generally be categorized as these two: the contactual method and non-contactual method; and in this study, we will find ways to lower the cost for a CMM, or a coordinate measurement machine, and try to find an alternative. Furthermore, we will discuss some of the ways to improve the non-contactual measurement methods-optical interferometer method and the optical triangulation method. We will measure an object using a laser distance measuring device and Set the Point-contact result with the ball-bearing type and line-contact result with the bearing type, to decide on which probe type will be used.

• 한국컴퓨터정보학회논문지
• /
• 제21권9호
• /
• pp.149-156
• /
• 2016

This paper is concerned with education courses operating practices for basic computer literacy training. In this study, we propose an example for students to effectively measure and evaluate the achievement of defined ability in the performance measurement and analysis, learning objectives and learning outcomes set in operation throughout the course. Through research and development use case presents the tools for teaching method and effective and objective measurement of the related subjects. And based on the results, we propose the possibility of utilizing NCS-based course operation and education certification. In this study, the measurement process is based on the association with the objective of the development and operation, and measurement tools, measuring tools for measuring learning outcomes associated with the curriculum design methods for the measurement and evaluation of the case of the operation of the course units of learning outcomes and the method proposed.