• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.189-199
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• 1999

The revision was proposed for methods A-weighted sound pressure measurement for fans, blowers and compressors in order to apply newly developed measurement techniques to KS B 6361 established in 1987. This proposal includes modification of terminologies, revision of sound power methods for radiated sound from the body, inclusion of In-duct measurement method, and correction method for flow noise upon microphon.

• 전기의세계
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• v.29 no.2
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• pp.118-128
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• 1980

The properties of plasmas produced by high power glass laser were investigated with various methods of diagnostics. Electron temperature was estimated by measurement of soft X-ray, and ion temperature was estimated by measurement of the time-of-flight of ion. The measurement of incident and reflected laser light, and Schlieren and shadowgragh methods were also used. No influence of laser pulse duration on the temperature was observed in the case of durations 2, 4 and 10 nsecs. The effective heating of plasma occurred in about 2 nsec of beginning of incident laser pulse. The experimental results for fast rising laser pulse were discussed and the influence of resetime of laser pulse on the heating of plasma was described. Neutrons produced by irradiating laser beam to solid deuterium target were detected.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.71-74
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• 2003

Fall-of-potential method is used usually to measure the ground impedance of large scale grounding system exactly. Because the interlinked magnetic flux between closed loops to inject test current and to measure potential rise is existed in E-P-C straight line arrangement, mutual(or inductive) coupling influences greatly on the measurement correctness. Measurement errors produced from inductive coupling could be reduced by the arrangement methods of auxiliary electrodes. Right angle or P-E-C order arrangement methods were effective to reduce the inductive coupling and the decrease degree of measurement error was analysed as quantitative through an experiment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.61-64
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• 2010

Footing Resistance of a 154 kV transmission towers in korea is commonly required to be less than 15 ohm to avoid lightning back-flashover accident. The periodic measurement of Footing Resistance is important to verify that the grounding performance of the towers has been maintained good. Towers are electrically connected in parallel with overhead grounding wire, therefore footing resistance of each tower will be measured after disconnecting the overhead ground wires from the towers. however, In this paper, three direct measurement methods of footing resistance are presented. There are very useful methods without disconnecting overhead ground wires from the tower under measurement. They are compared in KEPCO 154 kV transmission towers. The experimental results describe performances of them.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.441-448
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• 2006

In-cylinder flows such as tumble and swirl play an important role on the engine combustion efficiencies and emission formations. The tumble flow, which is dominant in current high performance gasoline engines, is able to effect fuel consumptions and emissions under a partial load condition in addition to the volumetric efficiency under a wide open throttle condition. Therefore, it is important to optimize the tumble ratio of a gasoline engine for better fuel economy, lower emissions, and maximum volumetric efficiency. First step for optimizing a tumble ratio is to measure a tumble ratio accurately. For a tumble ratio measurement, many different methods have been developed and used such as steady flow rig, PIV, PTV, and LDV. However, it is not well known about the relations among the measured tumble ratios using different methods. The purpose of this research is to correlate the tumble ratios measured using three different methods and find out merits and demerits of each measurement method. In this research the tumble flow was measured, compared, and correlated using three different measurement methods at the same engine: steady flow rig; 2-dimensional PIV; and 3-dimensional PTV water flow rig.

• Korean Journal of Oriental Medicine
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• v.13 no.3
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• pp.125-131
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• 2007

Objectives: We intended to know sensitivity, specificity and relation of diagnosis methods of Sasang Constitution. Methods: We compared QSCC II, PSSC, Body measurement dignosis results with gold standard ones which were diagnosed by Sasang Constitution specialist, and analyzed by crosstables to get the sensitivity and specificity of those. Results and conclusions 1. Sensitivity and specificity of one diagnosis method were low, so call, in QSCC II, Taeumin is 49% in sensitivity, 97% in specificity, Soeumin is 67%, 69%, Soyangin is 59%, 75%, in Body measurement, Taeumin is 66%, 89%, Soeumin is 70%, 82%, Soyangin is 49%, 78%. in PSSC, Taeumin is 57%, 90%, Soeumin is 88%, 62%, Soyangin is 18%, 88%. 2. When two diagnosis methods are consistent each other, sensitivity and specificity are more higher than one diagnosis method. 3. When three diagnosis methods are all consistent, sensitivity and specificity are most highest, but in Soyangin, those are decreased comparing with the case of consistency between QSCC II and Body measurement.

• Progress in Superconductivity and Cryogenics
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• v.25 no.1
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• pp.16-20
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• 2023

The International Electrotechnical Commission (IEC) 61788-26:2020 provides guidelines for measuring the critical current of Rare-earth barium copper oxide (REBCO) tapes using two methods: linear ramp and step-hold methods. The critical current measurement criterion, 1 or 0.1 μV/cm of electric field from IEC 61788-26 has been normally applied to REBCO coils or magnets. No-insulation (NI) winding technique has many advantages in aspects of electrical and thermal stability and mechanical integrity. However, the leak current from the NI REBCO coil can cause distortion in critical current measurement due to the characteristic resistance which causes the radial current flow paths. In this paper, we simulated the NI REBCO coil by applying both linear ramp and step-hold methods based on a simplified equivalent circuit model. Using the circuit analysis, we analyzed and evaluated both methods. By using the equivalent circuit model, we can evaluate the critical current of the NI REBCO coil, resulting in an estimation error within 0.1%. We also evaluate the accuracy of critical current measurement using both the linear ramp and step-hold methods. The accuracy of the linear ramp method is influenced by the inductive voltage, whereas the accuracy of the step-hold method depends on the duration of the hold-time. An adequate hold time, typically 5 to 10 times the time constant (τ), makes the step-hold method more accurate than the linear ramp method.

• Journal of KIISE:Information Networking
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• v.32 no.4
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• pp.495-507
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• 2005

Measuring the end-to-end available bandwidth in the Internet is a useful tool for distributedapplication services or QoS (Quality-of-Service) guarantee. To measure the end-to-end available bandwidth, Single-hop Gap model-based packet train measurement techniques are well-known. However, the error of packet train output gap can happen by network topologies. This error of the output gap causes the inaccuracy of the available bandwidth measurement. In this paper, we propose a new end-to-end available bandwidth measurement technique with accurate capacity measurement and fast convergence methods. To solve the erroneous capacity measurement problem of the back-to-back packet train transmission, we propose a new available bandwidth measurement method by decoupling the capacity measurement with the initial gap of the packet train. Also, we propose a new technique to predict the proper initial gap of the packet train for faster convergence. We evaluate our proposed method by the simulation in various topologies comparing with previous methods.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.567-576
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• 2007

In order to assess the on-site applicability of 3D absolute displacement monitoring of tunnel using digital photogrammetry, the displacement of the optical target placed at the measurement section was investigated, as planned in the OO tunnel construction site. The targets on 3 measurement lines only were considered for each point of measurement for the reconstruction of 3D cubic model for the digital vision monitoring. For each 3D model, 3 or more images have to be obtained at each point. On the last 2 measurement lines, 6 targets (crown, left and right walls) were continuously overlapped to construct 3D models so that 6 or more apices can be shared by 2 3D models. In order to compare the measurement methods of 3D absolute displacements in tunnel excavation, i. e, total station and digital image measurement, both the digital image measurement and optical measurement were conducted for 10 times in the same work section. The time and measurement results of both methods were compared.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.93-101
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• 1998

In Integrated Tube Components(ITC) process in themanufacturing of color display tube, we describe the necessity of the convergence measurement method using photo sensors. Compared with methods using 1D or 2D cameras, its characteristics is to use of moving image patterns and fixed sensors. This measurement method is formulated as the measurement problem of the phase difference in phase changing periodic signals. The convergence measurement system using photo sensors, for the good performance, must have a small standard deviation for the repetitive measurement in the same condition and a fast measurement time for thecovergence change. By above two conditions, we proposed the real time measurement algorithm of the pahse difference using fundametal and harmonic in phase changing periodic signals. And, the proposed algorithm is applied to the convergence measurement system.