• Tribology and Lubricants
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• v.29 no.1
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• pp.1-6
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• 2013

Hydraulic transmission is the main component delivering power to the drive wheels of an excavator during forward and backward movement, and it has low speed, high torque and high speed, low torque gear change ratios as a forward/backward two-speed main function. It also has additional function of ensuring that the excavator is stably fixed on the ground with the built-in parking brake during excavation operations. In this study, optimal design specifications are determined by modeling and simulating about the multi-disc-type friction clutch, which is the main component improving the reliability of the hydraulic transmission for a 14-ton wheel excavator, and the friction properties of the transmission clutch are analyzed by performing sample tests.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.344-353
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• 1994

This study numerically analyzed the dynamic characteristics of the frequency response on the pneumatic transmission line with load impedances. The pressure transfer function is represented by the distributed parameter line model. To validate the mathematical approximations of Bessel function ratios, the results of frequency response in a blocked line were compared with those obtained by the Infinite-product, Brown's and Square-root approximations. Special emphasis was given to the frequency response characteristics on the pneumatic transmission line with load impedances. Computations were carried out for the wide range of parameters in terms of load capacitance ratio and load resistance ratio. The present results indicated that the theoretical model is capable of accurately predicting the frequency response characteristics for any configuration of a fluid transmission line.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.1
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• pp.75-81
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• 2012

In this paper, the wireless power transfer system using the magnetic resonance was designed, analyzed by circuit analysis methode and the calculated transfer function was compared with the measured one. The self-resonant coil was made up of the commonly used capacitor which had the lumped capacitance and it enabled the stable magnetic resonance not to be affected by the circumstance. The transmission efficiency of this system was 70[%] at the 15[cm] between the transmission and receiving coil and the measured transfer function was similar to the calculated one, which means the circuit analysis methode is valid in this system. When the intermediate coils were added between the transmission and receiving coil, the transmission efficiency was increased, which produced the increase of transfer distance. In the case of the five intermediate coils adding, the 35[%] transmission efficiency was achived at the 90[cm] distance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.783-786
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• 2015

Hole attack, which is disturbed transmission function through change of routing information, can cause critical results for MANET as non-infrastructure network. Backhole attack, as a typical hole attack, is one malicious attack which is disabled network transmission function by assumption of transmission data through modification of routing information. It is very important to evaluate transmission performance caused by blackhole attack, because transmission performance of MANET is affective with blackhole attack. In this paper, transmission performance is analyzed with MANET under multiple blackhole attacks caused multiple blackhole nodes. Computer simulation based on NS-2 is used as analysis tool and voice traffic is considered ad application service on MANET.

• Journal of Biomedical Engineering Research
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• v.38 no.5
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• pp.219-226
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• 2017

Penalized-likelihood (PL) reconstruction methods for transmission tomography are known to provide improved image quality for reduced dose level by efficiently smoothing out noise while preserving edges. Unfortunately, however, most of the edge-preserving penalty functions used in conventional PL methods contain at least one free parameter which controls the shape of a non-quadratic penalty function to adjust the sensitivity of edge preservation. In this work, to avoid difficulties in finding a proper value of the free parameter involved in a non-quadratic penalty function, we propose a new adaptive method of space-variant smoothing with a simple quadratic penalty function. In this method, the smoothing parameter is adaptively selected for each pixel location at each iteration by using the image roughness measured by a pixel-wise standard deviation image calculated from the previous iteration. The experimental results demonstrate that our new method not only preserves edges, but also suppresses noise well in monotonic regions without requiring additional processes to select free parameters that may otherwise be included in a non-quadratic penalty function.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.875-879
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• 1998

A fault on the transmission line results in the variation of reactance and parametric uncertainties in the power system dynamics. In this case, we need a robust control to cope with these uncertainties. A sliding mode control, a sort of robust control, is known to be robust to parametric or state-dependent uncertainties if the bounding function of uncertain terms is determined a priori. However, in general, we can not readily determine the bounding function for the complex systems. Hence, in this paper we introduce a fuzzy system which can estimate the bounding function in relatively simple way. By the use of the proposed fuzzy system, determination of bounding function is made easier. We applied the proposed scheme to the stabilization of power system under the sudden fault on the transmission lines. The simulation result verifies the effectiveness of the scheme.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.875-880
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• 2002

It is necessary to determine the vibration source and its transmission paths in order to develop a low-noise compressor. Through the use of multiple-input/single-output(MISO) mode1, the transmission paths of vibration within a reciprocating compressor have been investigated. In order to identify the transmission path, we measure the accelerations of the block and transverse vibrations of the line discharge tube. As outputs, vibrations of compressor shell were measured at three positions; cylinder head, one near the suction line, and the top of upper shell. The partial coherence function and transfer function are obtained ken the measured data, and the results are observed in order to determine vibration source and its influence on the shell vibration.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.225-227
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• 2006

The transmission network clustering using a fuzzy entropy function are proposed in this paper. We can define a similarity measure through a fuzzy entropy. All node in the transmission network system has its own values indicating the physical characteristics of that system and the similarity measure in this paper is defined through the system-wide characteristic values at each node. However, to tackle the geometric mis-clustering problem, that is, to avoid the clustering of geometrically distant locations with similar measures, the locational informations are properly considered and incorporated in the proposed similarity measure. In this paper, a new regional clustering measure for the transmission network system is proposed and proved. The proposed measure is verified through IEEE 39 bus system.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.393-395
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• 2006

In competitive market, it is important to establish a plan of transmission expansion considering uncertainty of future generation and load behavior. For this reason, revised transmission expansion model is proposed in this paper. In the proposed model, information of predictable future condition are included in a cost function of transmission expansion investment. Also, to reduce risk of the investment, mean-variance Markowitz approach is added to the objective function of cost. By optimization programming, the most robust and the minimum cost plan can be obtained.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.78-89
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• 1992

The most important criteria of quality of meshing and contact of gears are the low level of noise and the sufficient dimensions and location of the contact. A new approach for determination of machine-tool settings for spiral bevel gears is proposed. The proposed settings provide a function of transmission errors, the desired location and orientation of contact. The function is able to absorb piece-wise linear functions of transmission errors that are caused by the gear misalignment and to reduce the gear noise. The determination of pinion machine-tool settings is based on the local synthesis of gears. A computer program for simulation of meshing bearing contact and determination of transmission errors for misaligned has been developed.