• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.109-115
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• 2004

Dust scattering is one of the major problem for the residents living nearby construction field with construction noise and vibration. The dust scattering may inflict a considerable damage to psychological, spiritual discomfort to neighboring peoples. Therefore, the trouble of residents living nearby construction field have been increasing. Nevertheless, in our country, adequate guidelines for the dust scattering are not yet established because of the lack of basic data and insufficient research works. In this point, this study has researched its level of damage by conducting of the interview-survey which utilizing of questionnaire-paper asking for those staffs and workers to answer in the construction field, in order to grasp the damage extent of the actual condition effect and response against scattering dust in construction field. As the result, the occurring rate of dust scattering was appeared high compare with other constructing processes, due to utilization of construction equipment that operating at the fundamental basic construction stage, and it was turned out that presently the proper countermeasure and training against scattering dust in the construction site is insufficient. As for the solution mean against that, it is considered that with the better operation of construction site such as the installation of facilities for occurrence-restraint of dust scattering, frequent sprinkling of water, use of thermostat-covers, as well as those methods to be minimized of the occurrence of dust scattering must be contrived through the education for an attention how to use of construction equipment and training at the site.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.2
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• pp.46-52
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• 2003

In this paper, the wavelet watermarking algorithm based on adaptive weight MASK processing as a watermark embedded-method for Copyright Protection of Digital contents is Proposed. Because watermark induce as a noise of original image, the watermark size should be limited for preventing quality losses and embedding watermark into images. Therefore, it should be preserve the best condition of the factors, robustness, capacity and visual quality. Tn order to solve this problem, we propose watermarking embedded method by applying adaptive weight MASK to the algorithm and optimize its efficiency. In that result, the watermarked images are improved about external attack. Specifically, correlation coefficient has over 0.8 on both modifications of brightness and contrast. Also, correlation coefficient of wavelet compression of embedded watermark last by over 0.65.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.243-247
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• 2004

The dynamometers which had made in a long time ago could not control the input/output quantity of water minutely and was sensitive to a noise since it was controlled by an analog control method. Therefore, a fully digital controlled system was urgently required to be robust against various noises. In this paper, the new system which can control the amount of circulated water in dynamometer was developed. This system is consisted of an industrial digital type controller and a servo motor. The industrial PLC was used as a main controller for the developed system, and the actuator and servo motor were used to control the inlet and outlet valve independently. The torque signal of load cell was fed back to the main controller to regulate the diesel engines load. Generally, an input/output valve position of the old dynamometer was fixed with a proper situation for an engine output test and the torque was changed according to the time interval. However, the torque value for the dynamometer could not be constantly kept because of the variation of the input water flow and fluid characteristic. Therefore, the automatic control of an inlet and outlet valve should be performed to keep the constant torque. So, the PID control method was applied to solve this problem. Also, the development of a web-based remote control system was described in this paper. This software will give us the convenience of operation, the more efficient operations, and the reduced operator workload for operation of the dynamometer. The application results of the system have been verified at actual diesel engine field.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2087-2089
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• 2003

The presence of narrowband interference (NBI) in Direct-sequence code division multiple access (DS/CDMA) systems is an inevitable problem when the interference is strong enough. The improvement in the system performance employs by adaptive narrowband interference suppression techniques. Basically there have been two types of method for narrowband interference suppression estimator/subtracter approaches and transform domain approaches. In this paper the focus is on the type of estimator/subtracter approaches. However, the binary direct sequence (DS) signal, that acts as noise in the prediction process is highly non-Gaussian. The case of a Gaussian interferer with known in an autoregressive (AR) signal or a digital signal and also in a sinusoidal signal (Tone) that included in is paper. The proposed NBI suppression is presence in an adaptive IIR notch filter for lattice structure and more powerful by using a variable step-size algorithm. The simulation results show that the proposed algorithm can significantly increase the convergence rate and improved system performance when compare with adaptive least mean square algorithm (LMS).

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.3-8
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• 2016

We propose a modified form of the decision-directed least mean square (DD LMS) algorithm that is widely used in the optimization of self-adaptive equalizers, and show the modified version greatly improves the initial convergence properties of the conventional algorithm. Existing DD LMS regards the difference between a equalizer output and a quantization value for it as an error, and achieves an optimization of the equalizer based on minimizing the mean squared error cost function for the equalizer coefficients. This error generating method is useful for binary signal or a single-level signals, however, in the case of multi-level signals, it is not effective in the initialization of the equalizer. The modified DD LMS solves this problem by modifying the error generation. We verified the usefulness and performance of the modified DD LMS through experiments with multi-level signals under distortions due to intersymbol interference and additive noise.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.155-163
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• 2012

The geometrical and electrical errors of array sensors can severely degrade the performance of array sensor system. Various calibration techniques are developed to alleviate this problem. In this paper, two different calibration methods with respect to location, gain and phase of array sensors are presented. One method applies the first-order Taylor series expansion to approximate the true steering vector from the nominal values of array sensors. Then a set of equations is formed by using the null characteristics of the MUSIC spectrum to estimate errors of location, gain and phase of array sensors. Another method estimates these errors based on the data covariance matrix of pilot sources. From the simulations, it is demonstrated that two calibration algorithms calibrated an array system successfully. In addition to that, Fistas and Manikas's algorithm is more robust against noise than Ng and Lie's one when SNR is from 10dB to 50dB.

• The Journal of the Acoustical Society of Korea
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• v.33 no.4
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• pp.248-254
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• 2014

Among acoustic signal analysis tasks, acoustic context awareness is one of the most formidable tasks in terms of complexity since it requires sophisticated understanding of individual acoustic events. In conventional context awareness methods, individual acoustic event detection or recognition is employed to generate a relevant decision on the impending context. However this approach may produce poorly performing decision results in practical situations due to the possibility of events occurring simultaneously or the acoustically similar events that are difficult to distinguish with each other. Particularly, the babble noise acoustic event occurring at a bus or subway environment may create confusion to context awareness task since babbling is similar in any environment. Therefore in this paper, a frequency-cepstral feature vector is proposed to mitigate the confusion problem during the situation awareness task of binary decisions: bus or metro. By employing the Support Vector Machine (SVM) as the classifier, the proposed feature vector scheme is shown to produce better performance than the conventional scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.1
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• pp.165-170
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• 2015

The unsharp mask technique emphasize the boundary of the image by adding the boundary of the original image. This technique improves quality by emphasize its boundaries but produce rough image from image noise. The multi channel unsharp mask is possible to enhance entire contrast of the image by applying at least two channels of unsharp mask. However, There is limitations to strengthen boundaries even if the scale strongly applies the multi channel unsharp mask technique. To solve this problem, linear scaling to nonlinear scaling by applying exponential function to existing multi channel unsharp mask technique. Experimental results show enhanced contrast for desired area because of control scaling in details compared with existing unsharp mask technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1410-1413
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• 2016

Array beamforming for anti-jamming means that jamming signals are superposed destructively, while superposing information signals constructively at a receiver. However, according to channel state variation, the anti-jamming performance of the beamforming can be degraded because of large beamwidth of the sidelobe and lower selectivity of the mainlobe. To mitigate this problem, we introduce a beamformed decoy signal which uses frequency band distinguished from the information signal to make the jammer concentrate its jamming power to a wrong target under limited feedback. In this paper, we show that the performance of the proposed scheme can approach that of optimal one with perfect feedback.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.521-526
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• 2016

This paper suggests a new design that makes use of rotary inertia that can allow autonomous movement of an autonomous colonoscope robot in the colon of a patient as a locomotive mechanism. As commercial colonoscopy causes a lengthy time of pain and discomfort to the patients when colonoscopy patients are reluctant to receive surgery, there is a tendency to avoid the test in the early diagnosis of colorectal cancer. To solve this problem, research has been conducted on the next generation of robotic colonoscopes that can reduce the discomfort and pain by moving autonomously within the colon of the patients. In the driving mechanism utilizing the rotational inertia, a flywheel is driven by a motor to store energy and produce rotational inertia. By the energy stored and released by the flywheel, the stick phenomenon that occurs when the robot is running in the intestine can be overcome effectively. To do this, a controller that can control the velocity of the flywheel and is robust to high frequency noise was designed and implemented. The driving mechanism using the rotational inertia presented here showed that the structure is also effective and the experiment can be run easily compared to another mechanism.