• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.4
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• pp.82-89
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• 1996

In this study, to choose the drilling m/c with analysis model for dynamic design of machine tool strctures, are used substucture syntheis method for reduction to degrees of freedom of dynamic model and analysis evaluation of substructures The dynamic factors of substurctures are examined by substructure synthesis method. And that dynamic design of structures for energy balancing are performed. The computer program for calculated of the dynamic and energy distribution analysis was developed. Result of numerical analysis by developed program obtained to conclusion as following. The design of machine tool structures by dynamic avoid the resonances, and are known to considered based on the energy balancing. These methods can be used effectively for the performance evaluation, design modification and improvement of dynamic performance evaluation, design modification and improvement of dynamic performance of machine tools.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.85-92
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• 2006

For the improvement of a conventional railway speed, tilting train(Tilting Train express) is under the development aiming for a maximum speed 180km/h. Compared to the existing conventional rolling-stock, tilting train could take an advantage of speed improvement about $20{\sim}30%$ on curve sections due to the improvement of cowing performance. However, this speed increasement creates a severe load at wheels, thus it is necessary to study the safety of wheel for tilting train preferentially. On the other hand, it is under consideration that the wheel for conventional railway rolling-stock at speeds of 150km/h will be applied to tilting train at speeds of 180km/h. In this paper, we have studied the strength of wheel structure, the geometrical contact characteristics, and the dynamic performance of wheel to evaluate the safety of wheel for tilting train.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.929-930
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• 2006

This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Moto (SRM) with a novel 4-level converter to obtain smooth torque and dynamic performance improvement. The DITC method can reduce the high inherent torque ripple of SRM drive system, but driving efficiency and dynamic performance are somewhat low due to the slow excitation current build-up. Since the 4-level converter can obtain a addition high voltage to get fast excitation current and demagnetization current, so, it can improve dynamic performance easily. As a high performance SRM drive system with low torque ripple and high dynamic performance can be implemented. The validity of proposed method is verified by some computer simulations and comparative experiments.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.78-84
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• 2012

This paper presents a branch prediction algorithm and a 4-way set-associative cache for performance improvement of an embedded RISC core and a clock-gating algorithm with observability don’t care (ODC) operation to reduce the power consumption of the core. The branch prediction algorithm has a structure using a branch target buffer (BTB) and 4-way set associative cache that has a lower miss rate than a direct-mapped cache. Pseudo-least recently used (LRU) policy is used for reducing the number of LRU bits. The clock-gating algorithm reduces dynamic power consumption. As a result of estimation of the performance and the dynamic power, the performance of the OpenRISC core applied to the proposed architecture is improved about 29% and the dynamic power of the core with the Chartered 0.18 ${\mu}m$ technology library is reduced by 16%.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.1
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• pp.17-24
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• 2009

The performance improvement of a small-size integrated-type fully hydraulic breaker is studied in this paper. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected and nearly optimized to maximize the impact energy as well as to improve the dynamic characteristics such as the piston upper chamber pressure, piston and valve displacements. As a result, the impact energy, blows per minute(bpm) and output power are increased by 52.9%, 1%, and 55.6%, respectively compared with the current design. The dynamic characteristics of the piston upper chamber pressure, piston and valve displacements are also improved by the design change.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.64-70
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• 2019

Wireless sensors have been developed in numerous ways for enhancing the convenience of installation, management and maintenance of sensors. Energy harvesting wireless sensors, which can collect energy from the external environment for permanent usage without the need of recharging and exchanging batteries, have been developed and employed used in Internet of Things and at various industrial sites. Energy harvesting wireless sensors are significantly affected by the sensor lifespan to sudden variation in the external environment. Furthermore, reduction in the sensor operating timespan can greatly affect the characteristics of the devices connected through a network. In this paper, a system performance index is proposed that can comprehensively evaluate the lifespan of a solar cell wireless sensor, determine the characteristics of devices connected to the associated network, and recommend dynamic power distribution control for improving the system performance index. Improvement in the system performance index was verified by applying the proposed dynamic power distribution control to an air conditioner network system using a solar cell wireless sensor. Obtained results corroborate that the dynamic power distribution control can extend the lifespan of the incorporated wireless sensor and reduce the air conditioner's power consumption.

• Journal of the Korea Society of Computer and Information
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• v.22 no.7
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• pp.39-45
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• 2017

In this paper, we propose three compensation methods to solve problems in high-resolution airborne infrared camera and to improve long-range target information acquisition performance. First, image motion and temporal noise reduction technique which is caused by atmospheric turbulence. Second, thermal blurring image correction technique by imperfect performance of NUC(Non Uniformity Correction) or raising the internal temperature of the camera. Finally, DRC(Dynamic Range Compression) and flicker removing technique of 14bits HDR(High Dynamic Range) infrared image. Through this study, we designed techniques to improve the acquisition performance of long-range target information of high-resolution airborne infrared camera, and compared and analyzed the performance improvement result with implemented images.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.2
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• pp.5-10
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• 2004

In this paper, the hybrid-type current controller for inverter TIG systems was implemented and it was shown that the low-current pulse wave forms with high dynamic performance could be obtained. It is not sri easy to obtain the optimum gain tuning of PID controllers in digital PWM control methods. Hybrid control methods which uses automatic tuning techniques after adding fuzzy control methods to traditional PID controllers are chosen to improve the dynamic performance of PID controller's. To demonstrate the practical significance and dynamic performance improvement of the results, some simulation and experimental results are presented.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.769-775
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• 2011

Custom power devices such as dynamic voltage restorer (DVR) and DSTATCOM are used to improve the power quality in distribution systems. These devices require real power to compensate the deep voltage sag during sufficient time. An interline DVR (IDVR) consists of several DVRs in different feeders. In this paper, a neural network is proposed to control the IDVR performance to achieve optimal mitigation of voltage sags, swell, and unbalance, as well as improvement of dynamic performance. Three multilayer perceptron neural networks are used to identify and regulate the dynamics of the voltage on sensitive load. A backpropagation algorithm trains this type of network. The proposed controller provides optimal mitigation of voltage dynamic. Simulation is carried out by MATLAB/Simulink, demonstrating that the proposed controller has fast response with lower total harmonic distortion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.667-668
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• 2012