Kuhn-Il Lee

A real-time self-tuning fuzzy controller through scaling factor adjustment for the steam generator of NPP

In this paper a self-tuning fuzzy water level controller based on real-time tuning of the scaling factors for the steam generator of a nuclear power plant is presented. There is a need for a real-time tuning technique for a large system which is safety related and availability related for the total system. A new real-time tuning of the scaling factors is proposed. The new tuning method uses a variable reference tuning index and an instantanuous system fuzzy performance. The controller is simulated on the Compact Nuclear Simulator at the Korea Atomic Energy Research Institute. The simulation results show that the proposed tuning method improves the performance of the water level controller.

Watermarking for 3D polygonal meshes using normal vector distributions of each patch

In this paper, we proposed a watermarking for 3D polygonal meshes using normal vector distribution of each patch. The distribution of norm vector for 3D polygonal mesh is a consistent factor to be robust against various attacks such as affine transform and mesh connectivity altering. Therefore, the proposed algorithm embedded watermark into these consistent normal vectors and equal watermark bit was embedded into each patch of subdivided mesh to have robustness against the partial geometric deformation. Experiment results exhibited the proposed algorithm is robust by extracting watermark bit for various attacked models.

Complex EGI Based 3D-Mesh Watermarking *

We proposed 3D-mesh watermarking using CEGI distribution that has robustness against mesh simplification, cropping, vertex randomization, and rotation and which does not need the original model for detection the watermark. The proposed algorithm embeds the watermark bits into the normal vector direction of meshes that are mapped into the cells that have the large magnitude of complex weight in patch CEGIs. The watermark can be detected based on the known center point of each patch and the rank table of the cell in each patch instead of original model. Experimental results verified that the proposed algorithm has robustness against the attacks.

3D polygonal meshes watermarking using normal vector distributions

We proposed 3D polygonal meshes watermarking using normal vector distribution to robust against various attacks. The norm vector distribution of mesh is a consistent factor that is robust against various attacks. After calculating these distributions of 6 patches respectively, the same watermark bits are embedded into the same ordered bins in the distributions of 6 patches. The experiment shows that the watermark is imperceptible and robust against various attacks.

A new digital video watermarking using the dual watermark images and 3D DWT

We propose the effective video watermarking algorithm to protect the copyright. We use the visible binary image as the watermark. Our watermarking procedure is based on the three-dimensional discrete wavelet transform (3D DWT) and the spread spectrum sequence. We pre-process two watermark images using the mixing and the pseudorandom permutation. After dividing a video sequence into video shots, we perform the 3D DWT. And then, the watermark is embedded into the 3D DWT coefficients considering the robustness and the invisibility. At this time, we use two spread spectrum sequences define as the temporal user key. Experimental results show that the watermarked frames are indistinguishable from the original frames subjectively and the proposed video watermarking algorithm is robust enough against attacks of the low pass filtering, the frame dropping, and the MPEG coding.

New electronic digital image stabilization algorithm in wavelet transform domain

In this paper, we presented a new wavelet-based digital image stabilization (DIS) algorithm on the motion estimation for the stabilization of the 2-axes rotation sight system. In proposed algorithm, we first estimate the local motion defined in terms of translational motion vector by using fine-to-coarse (FtC) multi-resolution motion estimation (MRME). Next, we estimate the global motion defined as the rotational motion parameters such as the rotational center and angular frequency by using the vertical and horizontal component in wavelet domain. The rotational center and angular frequency are estimated from the local motion field and the special subset of the motion vector respectively. The experimental results show the improved stabilization performance compared with the conventional digital image stabilization algorithm.

Digital watermarking based on three-dimensional wavelet transform for video data

With the increment of digital media, multimedia technology and copyright protection have been the important issue. In this paper, an effective watermarking algorithm is proposed to protect copyright of video data. In the watermark embedding step, a three-dimensional discrete wavelet transform (3D DWT) is used to decompose original video data, because a pirate can easily extract the watermark by statistically comparing successive frames in case that the watermark is embedded in spatial doamin. The binary image is used as the watermark. It is changed into the video watermark by a two-dimensional (2D) pseudorandom permutation and the spread spectrum technique. The video watermark is embedded into the 3D DWT coefficients of the selected subbands. In the watermark extracting step, the embedded video watermark is detected by the similarity of the unit of subband and the final watermark image is extracted by a watermark decision rule and a reverse permutation. Experimental results show that the watermarked frames are subjectively indistinguishable from the original frames, plus the proposed video watermarking algorithm is sufficiently robust against various attacks.

3D mesh watermarking using projection onto convex sets

The current paper proposes 3D mesh watermarking using projection onto convex sets. As such, a 3D mesh is iteratively projected onto two constraint convex sets until the convergence condition is satisfied. The sets consist of a robustness set and invisibility set designed to embed the watermark. The watermark can be extracted without the original mesh using the decision values and index that the watermark was embedded with. Experimental results verify that the watermarked mesh is both robust to mesh simplification, cropping, affine transformations, and vertex randomization and invisible.

Blocking artifacts reduction algorithm in block boundary area using neural network

A novel algorithm is proposed to reduce the blocking artifacts of block-based coded images by using block classification and feedforward neural network filters in the spatial domain. In the proposed algorithm, we classify the block boundaries into four classes based on a statistical characteristic of neighborhood block. For each class, adaptive inter-block filtering performs in block boundaries. That is, for the smooth region with blocking artifacts, we use the two-layer neural network with error backpropagation algorithm, and for the complex region with blocking artifacts, we use the linear interpolation method. Experimental results show that the proposed algorithm gives better results than the conventional algorithms from both the subjective and objective viewpoint.

Adaptive time-based location update scheme using fuzzy logic

This paper introduces an adaptive time-based location update scheme that dynamically determines when to perform location update based on the moving distance of the mobile station and the incoming call arrival probability using fuzzy logic.