• JSTS:Journal of Semiconductor Technology and Science
• /
• v.12 no.1
• /
• pp.24-33
• /
• 2012

This paper describes a multi-mode LDPC decoder which supports 19 block lengths and 6 code rates of Quasi-Cyclic LDPC code for Mobile WiMAX system. To achieve an efficient implementation of 114 operation modes, some design optimizations are considered including block-serial layered decoding scheme, a memory reduction technique based on the min-sum decoding algorithm and a novel method for generating the cyclic shift values of parity check matrix. From fixed-point simulations, decoding performance and optimal hardware parameters are analyzed. The designed LDPC decoder is verified by FPGA implementation, and synthesized with a $0.18-{\mu}m$ CMOS cell library. It has 380,000 gates and 52,992 bits RAM, and the estimated throughput is about 164 ~ 222 Mbps at 56 MHz@1.8 V.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.2
• /
• pp.981-984
• /
• 2005

Recently, filtering methods for attenuating noise while preserving image details are in progress actively. And SM(standard median) fille. showed a great performance for noise removal in impulse noise environment but, it caused edge cancellation error So, variable methods that modified SM(standard median)filter have been proposed, and CWM(center weighted median) filter is representative. Also, there are several methods to improve the efficiency based on min/max operation in term of preserving detail and filtering speed. In this paper, we managed a pixel corrupted by impulsive noise using min/max value of the surrounding band enclosing a pixel, and compared the efficiency with exiting methods in the simulation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.7
• /
• pp.1309-1314
• /
• 2007

The assignment of cells to reporting or non-reporting cells is an NP-hard problem having an exponential complexity in the Reporting Cell Location Management (RCLM) system. Frequent location update may result in degradation of quality of service due to interference. Miss on the location of a mobile terminal will necessitate a search operation on the network when a call comes in. The number of reporting cells and which cell must be reporting cell should be determined to balance the registration (location update) and search (paging) operations to minimize the cost of RCLM system. T1is paper compares Max-Min ant system (MMAS), rank-based ant system (RAS) and hybrid method of MMAS and RAS that generally used to solve combinatorial optimization problems. Experimental results demonstrate that hybrid method of MMAS and RAS is an effective and competitive approach in fairly satisfactory results with respect to solution quality and execution time for the optimal design of location management system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2006.05a
• /
• pp.1001-1004
• /
• 2006

Many researches have been processed to reconstruct corrupted an image by noise in fields of signal processing such as image recognition and compute. vision, and AWGN(additive white gaussian noise) and impulse noise are representative. Impulse noise consists of fired-valued(salt & pepper) impulse noise and random-valued impulse noise, and non-linear filters such as SM(standard median) filters are used to remove this noise. But basic SM filters still generate many errors in edge regions of an image, and in order to overcome this problem a variety of methods have been researched. In this paper, we proposed an impulse noise removal algorithm which is superior to the edge preserving capacity. At this tine, after detecting a noise by using the noise detector, we applied a noise removal algorithm based on the min-max operation and compared the capacity with existing methods through simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.359-362
• /
• 2007

According to the development of information and communication technology, a great deal of researches have been taken in image digital processing field. And for earning the standard level of images, to remove noises such as impulse noise has became a essential demand. In those algorithms which remove impulse noise effectively, the standard median (SM) filter is representative. However, it has a disadvantage to degrade the quality of overall image by occurring errors in the edge domain. Therefore, in this paper, to restore the corrupted image by impulse noise, a nonlinear spatial filter based on Min-max operation was proposed and it was compared with conventional methods through simulations.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1032-1034
• /
• 2001

As well known, a solar cell has an optimal operating point to be able to get the maximum power $P_{max}$. So, many $P_{max}$ tracking controllers using the line voltage of a solar cell have been popularly used. But it may vary depending on the miss match between the solar cell output and the load. In this paper, we investigate the possibilities of $P_{max}$ control using the current tracking controller and the output voltage and the output current instead of the solar cell output power. And we also examine about the optimal power converter using ZVCS step up and down chopper circuit to operate the solar cell at an optimal voltage using these variables. And then, we show some experimental results to confirm the successful operation.

• Proceedings of the Korea Institute of Convergence Signal Processing
• /
• 2005.11a
• /
• pp.167-170
• /
• 2005

Recently, filtering methods for attenuating noise while preserving image details are in progress actively. And SM(standard median) filter showed a great performance for noise removal in impulse noise environment but, it caused edge cancellation error. So, variable methods that modified SM(standard median) filter have been proposed, and CWM(center weighted median) filter is representative. Also, there are several methods to improve the efficiency based on min/max operation in term of preserving detail and filtering speed. In this paper, we managed a pixel corrupted by impulsive noise using min/max value of the surrounding band enclosing a pixel, and compared the efficiency with exiting methods in the simulation.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.31B no.8
• /
• pp.181-191
• /
• 1994

A new method for enhancing blurred images using fuzzy logic concepts is proposed. Blurred images contain blurred boundaries which make it difficult to detect edges and segment areas in images. In order to sharpen blurred edges local contrast information of an image and erosion/dilation properties of local min/max operations are used in which local min/max operations are fuzzy logic operations. so that given images are transformed to fuzzy images and then these operations are applied on them. In this method the sharpening operation can be iteratively applied to the image to get better deblurring effect and gray-scale "salt-and-pepper" noises are suppressed. the efficiency of our algorithm is demonstrated through experimental results obtained with artificially-made blurred images and real blurred images.

• Proceedings of the KIPE Conference
• /
• 2013.07a
• /
• pp.238-239
• /
• 2013

It is a crucial requirement to utilize an economical battery capacity for the wind energy conversion system. In this paper, the optimal BESS capacity is determined for the wind farm whose dispatched power is assigned by the min-max dispatching method. Based on a lifetime cost function that indicates the BESS cost spent to dispatch 1kWh wind energy into grid, the battery capacity can be optimized so as to obtain the minimum system operation cost. Moreover, the battery state of charge (SOC) is also managed to be in a safe operating range to ensure the system undamaged. In order to clarify the proposed optimizing method, a 3MW permanent magnet synchronous generator (PMSG) wind turbine model and real wind speed data measured each minute are investigated.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.10
• /
• pp.1109-1116
• /
• 1992

Mathematical morphology, theoretical foundation for morphological filter, is very efficient for the analysis of the geometrical characteristics of signals and systems and is used as a predominant tool for smoothing the data with noise. In this study, H/W design of morphological filter is implemented to process the gray scale dilation and the erosion in the same circuit and to choose the maximum and minimum value by a selector, resulting in their education of the complexity of the circuit and an architecture for parallel processing. The structure of morphological filter consists of the structuring-element block, the image data block, the control block, the ADD block, the MIN/MAX block, etc, and is designed on an one-chip for real time operation.