• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.876-881
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• 2006

In this paper, we propose a complex-valued IIR filter for digital VSB signals based on CMA in order to efficiently mitigate multipath distortions, especially the leakage from the quadrature component. The proposed equalizer overcomes the drawback of the conventional real-valued IIR equalizers that it attempts to equalize Hilbert transform of quadrature component. We demonstrate via simulation that the proposed complex IIR filter successfully mitigates the leakages from the quadrature component, while the conventional real IIR filter requires a longer IIR filter to achieve the same performance. We present cost function analysis for a simple two-tap case showing that the proposed IIR equalizer with CMA for VSB signals has a global minimum at the desired location.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.3-8
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• 1985

Molecular electronegativity (EN) values are calculated employing the density functional definition of EN: the negative of the chemical potential in the density functional theory. Calculations are limited to the use of valence electrons (valence electron approximation). Our formula for the EN is given in terms of Hartree-Fock(HF) orbital energies. Resulting EN values for molecules as well as atoms exhibit a remarkable correlation with other existing scales. For molecules, we have achieved electronegativity equalization principle (Sanderson's principle).

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.256-258
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• 2007

A charge equalization converter with parallel-connected primary windings of transformers is proposed in digest. The proposed work effectively balance the voltage among Lithium-Ion battery cells despite each battery cell has low voltage gap compared with its SOC. The principle of the proposed work is that the equalizing energy from all battery strings moves to the lowest voltage battery through the isolated dc/dc converter controlled by the corresponding bi-directional switch. In this digest, a prototype of four Lithium-Ion battery cells is optimally designed and implemented, and experimental results show that the proposed method has excellent cell balancing performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.117-126
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• 2009

The recent interest in sensor networks has led to a number of routing schemes that use the limited resources available at sensor nodes more efficiently. These schemes typically try to find the minimum energy path to optimize energy usage at a node. Some schemes, however, are prone to unbalance of the traffic and energy. To solve this problem, we propose a novel solution: a gradient-field approach which takes account of the minimum cost data delivery, energy consumption balancing, and traffic equalization. We also modify the backoff-based cost field setup algorithm to establish our gradient-field based sensor network and give the algorithm. Simulation results show that the overhead of routing establishment obtained by our algorithm is much less than the one obtained by Flooding. What's more, our approach guarantees the basic Quality of Service (QoS) without extra spending.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.160-166
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• 2015

This study proposes an improved cell balancing circuit for fast equalization among lithium-ion (Li-ion) batteries. A simple voltage sensorless charge balancing circuit has been proposed in the past. This cell balancing circuit automatically transfers energy from high-to low-voltage battery cells. However, the circuit requires a switch with low on-resistance because the balancing speed is limited by the on-resistance of the switch. Balancing speed decreases as the voltage difference among the battery cells decrease. In this study, the balancing speed of the cell balancing circuit is enhanced by using the auxiliary circuit, which boosts the balancing current. The charging current is determined by the nominal battery cell voltage and thus, the balancing speed is almost constant despite the very small voltage differences among the batteries. Simulation results are provided to verify the validity of the proposed cell balancing circuit.

• Membrane Journal
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• v.21 no.2
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• pp.107-117
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• 2011

The all vanadium redox-flow battery (V-RFB) is investigating as one of large-scale power storage systems. Particularly, V-RFB is being investigated as one of the power storage systems for the load leveling and output power equalization of the power systems using renewable energy such as solar and wind. In this paper, it was explained for the principle and construction, recent research review, economy, element technology in V-RFB.

• Journal of Internet of Things and Convergence
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• v.10 no.5
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• pp.53-63
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• 2024

The rapid development of wireless sensor network technology has garnered significant attention from researchers. In extensive distributed networks, these applications often rely on battery power. Given the limited energy capacity of batteries, effective energy management is crucial for improving network performance. Wireless sensor networks consist of numerous sensor nodes, where energy consumption is primarily driven by these nodes. In clustering protocols, certain nodes repeatedly serve as cluster heads, resulting in increased energy consumption compared to other nodes. This energy-balancing algorithm employs pruning techniques to evaluate and analyze a node's position, its frequency of acting as a cluster head, and its remaining energy. Additionally, it includes a dynamic adjustment mechanism for selecting the cluster head node. Experimental results demonstrate that this algorithm extends the operational duration of sensor nodes, thereby effectively prolonging the lifespan of the wireless sensor network.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.5
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• pp.393-400
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• 2012

The modularized equalizers normally use additional components among the modules in the long series-connected lithium-ion battery string. In these approaches, the overall systems are heavy, bulky, and high-priced. Furthermore, the losses related to additional components decrease the system efficiency. To avoid these problems, a modularized equalizer, which has no additional components among the modules, is required. This paper proposes a novel control scheme using the magnetizing energy of the multi-winding transformer for the module equalization. In this scheme, the high duty cycle is applied to the module where the voltage is higher than the reference voltage and the low duty cycle is applied to the module where the voltage is lower than the reference voltage. Due to the different duty cycle, more electric charges are transferred from high voltage module to the low voltage module during the turn-off switching interval. Using the proposed control scheme, the equalizer system does not suffer from the size, cost, and loss related to the modularization. The experimental results are provided to verify the effectiveness of the proposed modularized equalizer.

• Plant Journal
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• v.17 no.2
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• pp.42-47
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• 2021

In terms of district heating operation, efficient production and supply of heat by alleviating the peak load at a specific time require an application technology that can solve the inconvenience of the user and the difficulties of the supplier. In this study, a 78 ℃ class PCM heat storage tank suitable among the technologies that can solve these problems was manufactured and applied to the hot water supply facility for apartments in district heating users. As a result of the application of this system, it was confirmed that the supply temperature was constant to the user compared to the existing supply method. In addition, it was confirmed that the reduction of the peak load due to load equalization reduced the heat supply margin of 10% in the existing heat supply facility. And the construction cost of the new heat supply facility and the construction cost of heat users is decreased by 5% and 10%, respectively.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.9-16
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• 1997

We develop an automatic imaging matching technique for combining portal image and simulator image for improvements in localization of treatment in radiation therapy. Fusion of images from two imaging modalities is treated as follows. We archive images thxough a frame-yabber. The simulator and portal images are edge detected and enhanced with interpolated adaptive histouam equalization and combined using geometrical parameters relating the coordinates of two image data sets which are calculated using Fourier descriptors. We don't use any kind of imaging markers for patient's convenience. clinical use of this image matching technique for treatment planning will result in improvements in localization of treatment volumes and critical structures. These improvements will allow greater sparing of normal tissues and more precise delivery of energy to the desired irradiation volume.