• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.385-389
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• 2004

Test facilities for the wind turbine performance monitoring and mechanical load measurements are installed in Vestas 100 kW wind turbine in Wollyong test site, Jeju island. The monitoring system consists of Garrad-Hassan T-MON system, telemetry system for blade load measurement, various sensors such as anemometer, wind vane, strain gauge, power meter, and etc. The experimental procedure for the measurement of wind turbine loads, such as edgewise(lead-lag) bending moment, flapwise bending moment, and tower base bending moment, has been established. Strain gauges are on-site calibrated against load cell prior to monitoring the wind turbine loads. Using the established monitoring system, the wind turbine is remotely monitored. From the measured load data, the load analysis has been performed to obtain the load power spectral density and the fatigue load spectra of the wind turbine.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.839-844
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• 2012

Anemometer is a meteorological instrument that measures wind direction and wind speed in real time, and is mounted to the cranes that are used at ports, shipbuilding yards, off-shore structure, or construction sites that are influenced by wind, and it is used in conjunction with the safety system. Load cell-type anemometer measures the wind direction through the ratio of load between 4 positions by mounting the thin plate to 4 load cells, and measures wind velocity through the summation of loads. According to previous research, the load ratio between two adjacent windswept with respect to the wind direction has unstable value due to vortex around windswept. This causes the result that increases an error on the wind direction. In this study we compared and analyzed the difference between the load ratio with respect to three type windswept shapes in order to suggest the proper windswept shape to reduce this error. The computational fluid flow analysis is carried out with ANSYS CFX to analyze the load ratio between three windswept shapes. Wind direction was adopted as the design variable, and selected 9 wind direction conditions from $0^{\circ}{\sim}90^{\circ}$ with $11.25^{\circ}$ interval for computational fluid flow analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2443-2449
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• 2015

Downlink (DL) data rate for a MS is influenced by not only the signal to interference and noise ratio (SINR) but also the amount of radio resources allocated to the MS. Therefore, when a MS uses SINR to select a cell to associate with, it cannot receive the fastest DL data rate all the time if it associates with a congested cell. Moreover, the SINR-based cell selection may result in cell loads unbalance, which decreases the efficiency of a network. To address the issue, we propose a novel cell selection method by considering not only SINR but also a cell load which are combined into two cell selection criteria. One is the maximum achievable data rate and the other is the minimum outage probability. The simulation results show that the cell selection based on the maximum achievable data rate is superior to the SINR-based method and the method using the minimum outage probability in terms of the system efficiency and the fairness in cell loads while the cell selection method based on the minimum outage probability is superior to the others in terms of the outage probability of a MS.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.269-275
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• 2009

The use of lattice girder is increased at the tunnel site in Korea recently for the substitute of H-steel rib. However, field measurements at the lattice girder are rarely performed at the tunnel site and the method of the measurement is not well established. The use of the vibrating wire strain gauges used for the H-steel rib was proven to be not suitable for the strain measurements of the lattice girder according to the previous research. The credibility of the load cell was investigated using laboratory compression tests for load cells, specially manufactured for the lattice girder far this study, installed at the specimen of the lattice girder. The method of the tunnel instrumentation for the lattice girder using the load cell is given from the interpretation of the compression test results.

• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1095-1101
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• 2002

The load characteristics of engine main bearing are very important in the design of crankshaft and engine block. The stiffness of crankshaft and block, or the optimal dimension of the bearing can be determined according to the load level. This paper presents the load characteristics of engine main bearing. Two components of the main bearing load are measured during engine firing and motoring. The vertical and horizontal load components are measured by using the dynamic load cell mounted in each main bearing cap bolt. The measured main bearing loads are compared with calculated results by using the statically determinate method. The theoretical results, provided in this study, agreed well with the experimental results. The presented results are very useful for achieving optimal design of engine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.255-259
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• 2001

The spring constant of a micro coil spring was measured by uniaxial tensile test. The inner diameter of it is $35{\mu}m$ and the pitch size is about $23{\mu}m$. A suing constant measurement system was developed. It consists of control units, load cell units, linear stages and several specially designed jigs and fixtures. Load and displacement are measured using a commercial load cell of 1000g capacity and a magnetic scale of $0.5{\mu}m$ resolution. In this study, a method to measure the spring constant of micro coil spring is presented and the relationship between misalignment of specimen and measurement error is discussed.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.24-32
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• 1994

A force sensor of 30 MN capacity using build-up technique in which three load cells of 10 MN capacity are arranged in parallel was fabricated. A column spring element was adopted as a shape of a strain gage type load cell. Temperature compensation circuits were used to reduce the error of a load cell. It was estimated that the total error of the fabricated force sensor is less than 0.1 %. The force sensor may be used to calibrate or test material testing machines above 4.5 MN capacity in industries.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1287-1293
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• 2009

This paper presents an application of Harmony Search (HM) meta-heuristic optimization algorithm for optimal operation of microgrid system. The microgrid system considered in this paper consists of a wind turbine, a diesel generator, and a fuel cell. An one day load profile which divided 20 minute data and wind resource for wind turbine generator were used for the study. In optimization, the HS algorithm is used for solving the problem of microgrid system operation which a various generation resources are available to meet the customer load demand with minimum operating cost. The application of HS algorithm to optimal operation of microgrid proves its effectiveness to determine optimally the generating resources without any differences of load mismatch and having its nature of fast convergency time as compared to other optimization method.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.698-703
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• 2001

This paper is concerned with the nonlinear hyperelastic problem fur the incompressible characteristics of the rubber. Tension sensor is a strain gage type load cell element for a fence intrusion detection system and consists of the sensing part and the rubber housing. The analysis includes an elastic analysis and a hyperelastic analysis of a tension sensor for the deformed shape and variation of the maximum strain on the sensing part with respect to the vertical load. Numerical results show that the hyperelastic model is stiffer and less deformed than the elastic model. Comparing with the experimental test data, we know the hyperelastic model is the better approximation than the elastic model.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.593-603
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• 1997

Connection admission decision in ATM networks requires decision made in real time using fast algorithm. It is difficult to construct a model of the multiplexed traffic and thus, approximation of the traffic load is necessary. In this paper, we propose a measurement-based dynamic CAC(Connection admission Control) in ATM(Asynchronous Transfer Mode) networks, which observes current traffic by the moving window and set the window size to the value which is computed from the measured cell loss amount. It is based on the measurements of the traffic load over an admission period that is load enough to reflect the current traffic behavior instead of analytic modeling. And, the dynamic reallocation of bandwidth for each class leads to effective bandwidth utilization. The performance of proposed method is analyzed through computer simulation. The performance of proposed method is analyzed by using SIMAN simulation package and FORTRAN language. As can be seen in the simulation result, cell loss performance and bandwidth utilization have been increased.