• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.131-135
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• 1997

We implementated an ultrasonic wave cane for the blind. The cane detect walking obstacle and provide a walking direction. The cane used time of flight method of ultrasonic-wave for a measurement of obstacle distance and fluxgate geomagnetic sensor for guidance of walking direction. This system can detect an obstacle of upward, forward, downward and that warn to the blind with vibration, pitch sound. And the blind can know walking direction to voice output. As a result, the blind could efficiently avoid a exposed obstacle, obstacles beyond knee, an exposed street obstacle, a branch of tree person's height and it is usable search for surrounding land mark.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.261-265
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• 2008

This work presents a simplified efficient blind detection algorithm for orthogonal space-time codes(OSTBC). First, the proposed decoder exploits a proper decomposition approach of the upper triangular matrix R, which resulted from Cholesky-factorization of the composition channel matrix, to form an easy-to-solve blind detection equation. Secondly, in order to avoid suffering from the high computational load, the proposed decoder applies a sub-optimal QR-based decoder. Computer simulation results verify that the proposed decoder allows to significantly reduce computational complexity while still satisfying the bit-error-rate(BER) performance.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.2
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• pp.198-201
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• 2014

The phase frequency detector (PFD) is one of the most important building blocks of a phase locked Loop (PLL). Due to blind-zone problem, the detection range of the PFD is low. The blind zone of a PFD directly depends upon the reset time of the PFD and the pre-charge time of the internal nodes of the PFD. Taking these two parameters into consideration, a PFD is designed to achieve a small blind zone closer to the limit imposed by process-voltage-temperature variations. In this paper an enhanced architecture is proposed for dynamic logic PFD to minimize the blind-zone problem. The techniques used are inverter sizing, transistor reordering and use of pre-charge transistors. The PFD is implemented in 180 nm technology with supply voltage of 1.8 V.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.69-76
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• 2006

In this paper, we propose blind adaptation strategies for decision feedback equalizer (DFE) optimizing the operation mode between acquisitionand tracking modes based on adjustable soft decision devices. The proposed schemes select an optimal soft decision device to generate feedback samples for the DFE at a given noise to signal ratio, and apply corresponding adaptation rules which combine a blind infinite impulse response (IIR) filtering adaptation and the decision-directed least mean squared (DD-LMS) DFE adaptation. These adaptation approaches attempt to achieve not only smooth transition between acquisition and tracking of DFE but also mitigation of error propagation.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.43-46
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• 1999

Blind equalizers recover the transmitted data using signal's statistical characteristics only. Because of its computational simplicity and fast convergence rate, CMA is widely used in practice. Blind equalizers, however, converge much slowly than conventional equalizers which use the training signals. In order to improve the convergence rate, many modified blind equalization algorithms have been proposed. Among those, Normalized CMA (NCMA) was applied to increase the convergence rate by using the large step size. Unfortunately it can only be applied for the constant modulus signal constellation scheme. this paper, we propose the Selective NCMA (SNCMA) that improve the convergence rate of blind equalization algorithms by using NCMA for non-constant modulus signalling method such as QAM constellation. We achieved fast start-up convergence rate and reduced steady-state residual error.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.35-43
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• 2004

Illuminance and luminous levels in a small office space due to daylight were calculated to analyze the impact of daylight on contrast and lighting energy savings. Computer simulations were performed for four blind conditions under a clear sky condition. The blind conditions significantly impacted the illuminance an4 luminance level. Visual performance scores were calculated according to the transfer function that uses absolute contrast between target and background surface. The blind condition that had 45 tilted angle toward ground provided good contrast and performance scores. Using a control algorithm of an automated daylight dimming control system lighting energy sayings were predicted. For all blind conditions minimum lighting energy was consumed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.14-23
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• 1995

A new dual-mode algorithm for blind equalization of quadrature amplitude modulation (QAM) signals is proposed. To solve the problem that the constant modulus algorithm (CMA) converges to the constellation with the arbitrary phase rotation, with the modification of the CMA, the proposed algorithm accomplishes blind equalization and carrier phase recovery simultaneously. In addition, the dual-mode algorithm combining the modified constant modulus algorithm (MCMA) with decision-directed (DD) algorithm achieves the performance enhancement of blind convergence speed and steady-state residual ISI. So we can refer the proposed algorithm to as a scheme for joint blind equalization and carrier phase recovery. Simulation results for i.i.d. input signals confirm that the dual-mode algorithm results in faster convergence speed, samller residual ISI, and better carrier phase recovery than those of the CMA and DD algorithm without any significant increase in computational complexity.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.214-217
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• 2000

To help the blind to find the information easily on World Wide Web, this research has tried to develop the device which enables us to convert HTML for the general into HTML for the blind. This program consists of the items as follows: 1. Web Robot to gather the internet browser and the general HTML. 2. Restoring DB by Parsing process 3. Multimedia editor for the use of web DB to add the literal and acoustic description to the editing function. 4. Convertor which gathers the DB and then changes into HTML for the blind. This project is designed to make it easy for the manager to establish the web site for the blind. We expect that this program will basically help the blind to overcome the inequality in the common information.

• Journal of Korea Multimedia Society
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• v.18 no.3
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• pp.368-375
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• 2015

Nowaday, financial institutions provide secure mobile keyboard solutions to keep their mobile banking services safe. However, these are still vulnerable to attacks, such as shoulder surfing attack. Especially, in the case of handicapped person such as visual impairment and blindness, they are more vulnerable than ordinary person because of inconvenience of secure information input. Among them, we focused on the color blind. For the color blind, 4-color based secure keyboard method causes more inconvenience to notify exact color. Thus, we propose a secure mobile keyboard solution to provide advanced functionality for the color blind users. Our method is based on 4-color theorem to support color blind users. In addition, our scheme is robust against shoulder surfing attack. According to the evaluation result, our method offers increased security against shoulder surfing attack compare with existing methods.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.3
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• pp.174-178
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• 2002

This paper discusses a blind equalization technique for FIR channel system, that might be minimum phase or not, in digital communication. The proposed techniques consist of two parts. One is to estimate the original channel coefficients based on fourth-order cumulants of the channel output, the other is to employ RBF neural network to model an inverse system fur the original channel. Here, the estimated channel is used as a reference system to train the RBF. The proposed RBF equalizer provides fast and easy teaming, due to the structural efficiency and excellent recognition-capability of R3F neural network. Throughout the simulation studies, it was found that the proposed blind RBF equalizer performed favorably better than the blind MLP equalizer, while requiring the relatively smaller computation steps in tranining.