• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.11b
• /
• pp.243-248
• /
• 1999

MPEG-4에서 오류강인성(Error Resilience)를 위한 한 방법으로 Resynchronization Markers(RM)을 사용한다. 한 프레임이 시작될 때 StartCode를 사용하여 동기를 맞추고 몇 개의MacroBlock을 encoding한 후 일정한 비트수(Threshold 값)가 지나면 재동기 마커 표시하여 재동기를 한다. 이렇게 하므로서 한 프레임 내에서 어떤 부분에 에러가 발생하더라도 그 에러가 속해있는 비디오패킷(재동기 마커와 재동기 마커사이의 Data)만을 버리거나 RVLC(ReversibleVariable Length Codes)를 사용하여 Data를 복원할 수 있다. 그러나 만약 재동기 마커에 에러가 발생하거나 에러의 전파로 인하여 재동기 마커를 인식 못한다면 두 개 이상의 패킷이 손실되거나RVLC를 사용한 데이터 복원을 할 수 없다. 본 논문에서는 이를 막기위해 디코딩 전에 Prescan을 통해서 재동기 마커의 위치를 탐지하고 에러가 생긴 재동기 마커를 복원하는 방법을 제안하였다. 그리고 bitrate에 따른 MB(MacroBlock)의 크기와 비디오 패킷 크기(재동기 마커와 재동기 마커간의 거리)를 분석하여 재동기 마커를 찾는 루틴에 적용하였다.

• KIPS Transactions on Software and Data Engineering
• /
• v.7 no.3
• /
• pp.91-98
• /
• 2018

Automatic detection of pig wasting diseases is an important issue in the management of group-housed pigs. In particular, porcine respiratory diseases are one of the main causes of mortality among pigs and loss of productivity in intensive pig farming. In this paper, we propose a noise-robust system for the early detection and recognition of pig wasting diseases using sound data. In this method, first we convert one-dimensional sound signals to two-dimensional gray-level images by normalization, and extract texture images by means of dominant neighborhood structure technique. Lastly, the texture features are then used as inputs of convolutional neural networks as an early anomaly detector and a respiratory disease classifier. Our experimental results show that this new method can be used to detect pig wasting diseases both economically (low-cost sound sensor) and accurately (over 96% accuracy) even under noise-environmental conditions, either as a standalone solution or to complement known methods to obtain a more accurate solution.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2004.05a
• /
• pp.167-170
• /
• 2004

본 논문에서는 다양한 디지털 컨텐츠들 중에 디지털 비디오에 대한 워터마킹 방법을 제안하였다. 현재 비디오 압축 부호화의 기본 알고리즘으로 사용되는 DCT(discrete cosine transform)는 고압축을 수행할 경우 블록킹 현상이 심하게 나타나는 단점이 있다. 제안한 방법은 이러한 단점을 극복하고 점진적 전송 특성을 갖는 비디오를 위해 웨이브릿 변환 영역에서 SPIHT(set partitioning in hierarchical trees)를 이용한 비디오 부호화 과정에 워터마크를 삽입하였다. SPIHT 부호화 과정에서 비디오 신호의 시간 중복성을 이용한 I 프레임에 대한 이전 프레임의 움직임 벡터를 이용하여 I 프레임에 워터마크를 삽입한다. 워터마크 삽입 시 HVS(human visual system)를 이용하여 움직임 벡터 분석에 의해 선택된 영역에서 지각적 중요 계수 (PSC :perceptual significant coefficient)를 선택하여 워터마크를 삽입한다. 실험 결과 시간 중복성과 HVS를 이용하여 I 프레임에 워터마크를 삽입하였기 때문에 비가시성과 강인성이 우수함을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.529-532
• /
• 2012

This paper presents the system modeling, analysis, and controller design and implementation with a inverted pendulum system in order to test robust algorithm for sweeping machine. The balancing of an inverted pendulum by moving pendulum robot like as 'segway' along a horizontal track is a classic problem in the area of control. This paper will describe two methods to swing a pendulum attached to a cart from an initial downwards position to an upright position and maintain that state. The results of real experiment show that the proposed control system has superior performance for following a reference command at certain initial conditions.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.2
• /
• pp.299-306
• /
• 2011

In this paper, a blind adaptive equalization algorithm based on PDF-distance minimization and a set of Delta functions is introduced and its superior robustness against impulsive noise and multipath characteristics of underwater communication channels is proved. The conventional CMA based on MSE has shown to be incapable of coping with impulsive noise, and correntropy blind algorithm has also revealed to yield not satisfying performance for the mission. On the other hand, the blind adaptive equalization algorithm based on PDF-distance minimization and a set of Delta functions has been proved to solve effectively the problem of impulsive noise and multipath characteristics of underwater communication channels through theoretical and simulation analysis.

• The KIPS Transactions:PartA
• /
• v.10A no.4
• /
• pp.357-368
• /
• 2003

Evaluation of shape similarity for 3D models is essential in many areas - medicine, mechanical engineering, molecular biology, etc. Moreover, as 3D models are commonly used on the Web, many researches have been made on the classification and retrieval of 3D models. In this paper, we describe methods for 3D shape representation and major concepts of similarity evaluation, and analyze the key features of recent researches for shape comparison after classifying them into four categories including multi-resolution, topology, 2D image, and statistics based methods. In addition, we evaluated the performance of the reviewed methods by the selected criteria such as uniqueness, robustness, invariance, multi-resolution, efficiency, and comparison scope. Multi-resolution based methods have resulted in decreased computation time for comparison and increased preprocessing time. The methods using geometric and topological information were able to compare more various types of models and were robust to partial shape comparison. 2D image based methods incurred overheads in time and space complexity. Statistics based methods allowed for shape comparison without pose-normalization and showed robustness against affine transformations and noise.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10a
• /
• pp.655-657
• /
• 2004

본 논문은 안전등급 제어 기 기(Programmable Logic Controller) 에서 동작하는 실시간 운영체제의 안전성을 요구사항 단계에서 평가할 수 있는 검토항목을 개발하고 HAZOP(Hazard and Operability) 을 이용하여 현재 개발중인 PLC 운영체제에 적용한 경험 을 기술한다. HAZOP은 화학공장과 같은 산업에서 안전성을 평가하기 위한 방법으로 사용했던 방법론이다. 원자력발전소에 적용하기 위해 운영체제가 갖추어야 할 안전성 요건은 NUREG-0800의 BTP-14(Branch Technical Position)의 소프트웨어 기능특성 및 공정특성에 기술되어 있다. 이러한 기능적인 특성을 정확도, 신뢰성, 타이밍/사이징, 기능성, 강인성, 보안성 항목으로 나누고 세부적인 검토리스트를 만들어 HAZOP을 적용하여 평가하였다.

• Journal of KIISE:Software and Applications
• /
• v.31 no.2
• /
• pp.203-212
• /
• 2004

The watermarking is a method to achieve the copyright protection of multimedia contents. Among several media, the left documents show very peculiar properties: block/line/word patterning, clear separation between foreground and background areas. So algorithms specific to the text documents are required that meet those properties. This paper proposes a novel watermarking algorithm for the grayscale text document images. The algorithm inserts the watermark signals through the edge direction histograms. A concept of sub-image consistency is developed that the sub-images have similar shapes in terms of edge direction histograms. Using Korean, Chinese, and English document images, the concept is evaluated and proven to be valid over a wide range of document images. To insert watermark signals, the edge direction histogram is modified slightly. The experiments were performed on various document images and the algorithm was evaluated in terms of imperceptibility and robustness.

• Journal of Broadcast Engineering
• /
• v.13 no.4
• /
• pp.489-500
• /
• 2008

We propose a novel high-definition content watermarking algorithm that is highly feasible in UCC (User Created Contents) environment. We begin by addressing an association between broadcasting content and UCC in a view of copyrights, then present watermark requirements by analyzing various UCC editing-effect. Also, we provide a brief review of previous watermarking techniques that are supposed to satisfy the requirements. Our proposed scheme inserts a invisible watermark into both DC and AC components on $8{\times}8$ block DCT domain and extracts them after synchronization using DC image. Experimental results show that our technique satisfies the requirements of invisibility and robustness to a variety of attacks such as rotation, scaling, cropping, and JPEG compression, etc. Note that the proposed scheme is highly resilient to UCC edit attacks that are combined by many different types of watermark attacks.

• Proceedings of the IEEK Conference
• /
• 2001.09a
• /
• pp.239-242
• /
• 2001

영상에 워터마크를 삽입하는 것을 통신채널의 입장에서 해석한다면 워터마크는 신호로, 영상은 잡음으로 모델링이 가능하다. 따라서 이러한 잡음 속에서 신호에 대한 에러를 최소화하는 것이 워터마크의 추출을 최대화하는 것이라 할 수 있다. 통상적으로 Error Correction Code는 에러가 많은 통신채널에서 많이 이용되기 때문에 워터마킹 방법에서도 효과를 기대할 수 있다. 본 논문에서는 DCT 기반의 구간화 워터마킹 방법에 Turbo code를 이용하여 강인성 면에서의 향상된 성능을 실험 결과로 보이며, Turbo code의 해밍거리를 이용하여 워터마킹의 보다 효율적인 검출 방법을 제안한다.