• Journal of Korea Water Resources Association
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• v.57 no.10
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• pp.657-671
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• 2024

The objectives of this study propose a parameter estimation method that can consider both the total runoff and the runoff component by integrating the digital filter method and the long-term runoff models (SWAT, TANK), and evaluate the appropriateness of the applied methods. The study area is the Soyang River Dam basin, and parameter calibration and validation are performed by dividing it into a parameter estimation method considering the total runoff and a parameter estimation method considering the runoff component. In both methods, the fit between the observation and simulation runoff was excellent, and the model performance was found to be good with a coefficient of determination (R²) of 0.73~0.87, and NSE of 0.67~0.85. As a result of comparison with each method, it was confirmed that the simulation accuracy was improved when applying the method considering the runoff component in both the SWAT model and the TANK model. When comparing between the models, the SWAT model showed better statistics in both methods, but the effect of applying to the method was found to be insignificant. However, even though the TANK model did not specifically consider the physical characteristics of the methodology, the statistical value of NSE increased by 17% when integrating a method such as a digital filter. In other words, the applicability to the digital filter method was found to be better in the TANK model, and when a hydrograph separation method such as a digital filter is applied to a conceptual model such as this model, it is judged that more improved simulation results can be obtained than the physical model. Accordingly, it is judged that estimating the parameters by considering the runoff component will be more accurate than estimating the parameters by considering only the total runoff when simulating the hydrological model.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.1
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• pp.57-65
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• 2017

This paper presented a method of designing low-power feedback active noise control filter optimized for headphones/earphones. Using constrained optimization, we obtained a high order FIR noise control filter to ensure reasonable noise attenuation performance at high sampling frequency environment. Then using infinite impulse response (IIR) approximation method called Balanced Model Truncation (BMT), we obtained a low order IIR noise control filter suitable for low-power digital signal processing system like headphones/earphones. For further performance improvement, we utilized frequency warping method so that we could obtain more accurately approximated IIR filter and we ensured system stability by reconstructing the low order IIR filter in form of cascaded second order IIR filters. ANC simulation with white noise and stability test verified that the proposed algorithm had superior attenuation performance and better robustness compared to the conventional algorithm.

• Journal of Digital Contents Society
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• v.4 no.1
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• pp.81-90
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• 2003

Multimedia Platform box based on distributed environments have much effect on objects grouping for management of distributed resources. This paper utilizes weight and fuzzy filtering techniques for objects platform in distributed multimedia environments. Weight and Fuzzy filtering techniques perform grouping by references relation of multimedia objects and this paper proposes object dictionary structure.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.77-79
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• 2013

본 논문에서는 광원 정보를 사용하여 다양한 재생환경에서 효과적인 홀로그래픽 비디오 서비스를 제공하기 위한 방법을 제안한다. 제안하는 기법에서 부호화 과정에서는 가우시안 블러를 적용한 영상의 개수를 조절, 분리 하고 다운 샘플링 한 하나의 영상 압축을 한 뒤 전송한다. 이 영상을 다운 샘플링, 업 샘플링, 보간법, 양방향 필터 (Bi-lateral filter) 등의 기법을 이용하여 획득한 영상과 나머지 영상을 다운 샘플링과 업 샘플링 하여 더한 영상의 차를 압축하여 수신측으로 전송한다. 복호화 과정에서는 압축된 광원 정보를 복원한 후 기본계층 정보를 가진 영상을 업 샘플링과 보간법, 양방향 필터 (Bi-lateral filter) 등의 기법을 적용하고 수신자의 환경과 고려에 따라 차영상을 더 한 후 CGH를 통해 홀로그램을 획득하였다. 실험을 통해 제안하는 기법이 기존의 방법들 보다 우수한 홀로그램을 복원 할 수 있다는 것을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.961-968
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• 2007

Today, we can use radio communication device anywhere-anytime. Sometimes, we use the device in acoustic noise environment. The acoustic noise makes many problems in communication system. In acoustic noise environment, speaker cannot send clear information to receiver, because the received signal includes both speech signal and noise signal. A digital filter is useful to remove noise to get desired signal. One of methods is the adaptive digital filter using the adaptive noise canceller that automatically adjust filter parameters. This thesis addresses articulation algorithms against actual acoustic noises by means of two adaptive filtering methods. One is the adaptive noise canceller with two input channels and another is the spectral subtraction filter with one input channel. The experimental result from the proposed filter shows that the adaptive noise canceller is useful to reduce the non-stationary noises, while the spectral amplitude filter is effective for stationary noises.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.111-118
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• 2012

Recently, most of firms have continuously released new products satisfying various needs of customers in order to increase market share. As a lot of products with various functionalities, prices and designs are released in the market, users have difficulties in choosing an appropriate product, especially for information technology driven devices. In case of digital cameras, inexperienced users spend a lot of time and efforts to find proper model for them. In this study, therefore, we design and implement a personalized recommendation system using analytic hierarchy process, one of the multi-criteria decision making techniques, and hybrid filtering combining content-based filtering and collaborative filtering to recommend a suitable product for inexperienced users of information technology devices.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.51-56
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• 2011

In this paper, a variety of digital image processing technique was applied to improve the quality of medical images which is a chest CR image. And the image quality was performed. On the other hand, the high-frequency emphasis filtering and the histogram equalization were realized by MATLAB programs to better the contrast of the chest CR image. As a result of simulation, the sharpness of the original image was elevated by the high-frequency emphasis filtering and the histogram equalization. To evaluate the degree which is improved the image quality by the digital image processing, the subjective evaluation is used by the observation of the image. The sensitivity which is the probability to find a signal or a lesion is calculated. The sensitivity of the image performed the high-frequency emphasis filtering and the histogram equalization became more improved than that of the original and the digital image processing performed in the medical image improved the quality of the image.

• Journal of Digital Contents Society
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• v.11 no.4
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• pp.597-606
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• 2010

This paper describes a real-time camera tracking framework specifically designed to track a monocular camera in an AR workspace. Typically, the Kalman filter is often employed for the camera tracking. In general, however, tracking performances of conventional methods are seriously affected by unpredictable situations such as ambiguity in feature detection, occlusion of features and rapid camera shake. In this paper, a recursive Bayesian sampling framework which is also known as the particle filter is adopted for the camera pose estimation. In our system, the camera state is estimated on the basis of the Gaussian distribution without employing additional uncertainty model and sample weight computation. In addition, the camera state is directly computed based on new sample particles which are distributed according to the true posterior of system state. In order to verify the proposed system, we conduct several experiments for unstable situations in the desktop AR environments.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.179-182
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• 2002

본 논문에서는 디지털 이퀄라이저에 대하여 검토하고, 대역 및 이득에 따라 Q-factor를 가변시키는 디지털 이퀄라이저 필터를 제안한다. 제안한 기법은 고정된 Q-factor를 사용하거나, 대역에 따라 Q-factor를 결정하는 기존의 방법들에 비해 가청 주파수 영역에서의 대칭성과 이득 리플 등의 측면에서 우수하고, 기존의 방법과 동일한 수준의 하드웨어 복잡도를 보인다. 또한, 중심 주파수 선정에 따른 성능 변화에 대해서도 고찰한다.

• 전자공학회논문지 IE
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• v.49 no.2
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• pp.75-81
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• 2012

In this paper, restoration methods were applied to restore analog medicine images with an aged image added and then blurred by noises. To restore the aged image blurred by the blurring function and added by noises, it was applied to the restoration methods which are inverse filtering and wiener filtering which are linear restoration techniques and Lucy-Richardson's algorithm which is nonlinear restoration technique. Moreover, ROC curve, a subjective evaluation method, was applied to evaluate the image quality of the restoration image. The wiener filtering using the ratio of constants acquired better image than the inverse filtering, but both of them couldn't improve ability to make a diagnosis. The restoration image applied to Lucy-Richardson algorithm was the best performance of the applied techniques and its sensitivity and specitivity were improved by 15[%] as much performance as the original aged image.