• 산업경영시스템학회지
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• 제37권4호
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• pp.98-105
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• 2014

According to a simple survey on the current status of the assembly line design, it was found that trial and error methods on the basis of experiences have been used mainly in domestic manufacturing industries, even though there exist a lot of excellent line balancing studies. It seems that more practical researches should be carried out to develop user-oriented line balancing tools especially for small and medium-sized enterprises. This study presents a design of the line balancing tool which can support the line balancing tasks of nonspecialists. The proposed design tool is composed of three major modules: pre-process, line balancing, and post-process. In particular, pre-process and post-process are newly proposed to increase its ease of use. We applied the proposed design to a test problem and test result showed that our practical method may contribute to enhance the efficiency of production operations management.

• 방송공학회논문지
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• 제12권6호
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• pp.624-629
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• 2007

While single view video coding uses the temporal prediction scheme, multi-view video coding (MVC) applies both temporal and inter-view prediction schemes. Thus, the key problem of MVC is how to reduce the inter-view redundancy efficiently, because various existing video coding schemes have already provided solutions to reduce the temporal correlation. In this paper, we propose a global disparity compensation scheme which increases the inter-view correlation and a new inter-view prediction structure based on the global disparity compensation. By experiment, we demonstrate that the proposed global disparity compensation scheme is less sensitive to change of the search range. In addition, the new Inter-view prediction structure achieved about $0.1{\sim}0.3dB$ quality improvement compared to the reference software.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.5063-5073
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• 2016

In this paper, an efficient texture compression method is proposed for fast rendering, which exploits the spatial correlation among blocks through intra-picture block matching. Texture mapping is widely used to enhance the visual quality of results in real-time rendering applications. For fast texture mapping, it is necessary to identify an effective trade-off between compression efficiency and computational complexity. The conventional compression methods utilized for image processing (e.g., JPEG) provide high compression efficiency while resulting in high complexity. Thus, low complexity methods, such as ETC1, are often used in real-time rendering applications. Although these methods can achieve low complexity, the compression efficiency is still lower than that of JPEG. To solve this problem, we propose a texture compression method by reducing the spatial redundancy between blocks in order to achieve the better compression performance than ETC1 while maintaining complexity that is lower than that of JPEG. Experimental results show that the proposed method achieves better compression efficiency than ETC1, and the decoding time is significantly reduced compared to JPEG while similar to ETC1.

• 융합신호처리학회논문지
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• 제11권1호
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• pp.80-87
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• 2010

함수합성법은 주어진 입출력 데이터 쌍으로부터 입출력관계를 충족하는 함수를 예측하는 것으로, 특성을 알 수 없는 시스템을 제어할 때에 필수적이다. 일반적으로 시스템은 비선형인 성질을 갖는 경우가 많고, 함수 합성에 취급하는 변수, 정수, 제약 등으로 조합된 문제가 발생하기가 쉽다. 그 함수를 합성하는 방법 중 한 가지로 유전적 프로그래밍이 제안되고 있다. 이것은 함수를 트리구조로 표시한 함수 트리에 유전적 조작을 적용하여, 입출력 관계를 충족하는 함수 트리를 탐색하는 방법이다. 본 논문에서는 기존의 유전적 프로그래밍에 의한 함수 합성법의 문제점을 지적하고, 새로운 4종류의 개선법을 제안한다. 즉, 함수 트리를 탐색할 때에 함수가 복잡하게 되는 것을 방지하기 위하여 함수 트리의 성장 억제, 조기 수렴을 목표로 하는 국소 탐색법의 채택, 함수 트리 내의 필요 없이 길어지는 요소의 효과적인 삭제, 대상으로 하는 문제의 특성을 이용하는 방법이다. 이러한 개선법을 이용할 경우, 기존의 유전적 프로그래밍에 의한 함수 합성법보다도 짧은 시간에 우수한 구조의 함수 트리가 구해지는 것을 2-spirals 문제에 대하여 컴퓨터 시뮬레이션을 통하여 확인하였다.

• 한국통신학회논문지
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• 제32권11B호
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• pp.673-684
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• 2007

본 논문에서는 무선 센서 네트워크에서 노드의 simple flooding에 의해 발생되는 broadcast storm problem을 해결하기 위한 크로스 레이어 기반의 효율적인 flooding 기법인 FARNS (Flooding algorithm with Adaptive Retransmission Nodes Selection)를 제안한다. FARNS는 MAC과 PHY에서 각각 이웃노들의 식별 정보와 수신신호강도 정보를 수집하여 패킷의 재전송에 사용될 재전송 후보 노드를 선택하여 모든 노드가 수신 패킷의 재전송을 시도하여 발생하는 불필요한 에너지의 낭비를 방지한다. 성능평가를 위한 모의 실험에서는 패킷의 수신비율과 전송비율, 평균중복패킷의 수와 오버헤드 등의 평가기준에서 FARNS가 다른 flooding 기법들보다 우수한 성능을 보인다. 또한, 재전송 동작에서 사용되는 노드들의 비율을 조절함으로써 다양한 네트워크 환경에서의 요구사항을 만족시키는 동시에 broadcast storm problem을 해결한다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.221-224
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• 2004

무한 인터넷 시장의 영향으로 멀티미디어 자원의 범위 확대와 이를 통한 수익구조를 위한 저작권 관련 기술들이 무분별하게 연구 개.발되고 있다. 콘텐츠 보호기법, 관리기법, 유통기법 등이 콘텐츠 유통업체와 개발자들에 의해 개발되고 있지만 표준이 없는 개발 경쟁으로 인해 저작권 관리 시스템간의 혼란 및 상호 호환성에 문제가 제기되기에 이르렀다. 중복투자로 인한 콘텐츠 유통 구조의 비효율성과 표준이 없는 저작권 관리의 모호성을 해결하기 위해 ISO산하 MPEG 위원회는 MPEG-21 프레임워크를 개발하기 이르렀다. 프레임워크 내부의 데이터 구조는 XML을 기반으로 하고 있으며 저작권 관련 데이터 표준을 제정하기 위해 REL이라는 XML 기반의 저작권 표현 언어를 제안하고 표준화하였다. 그러나 REL을 저작하기 위해 전체 프레임워크를 이해해야 하는 둥의 저작 문제가 발생하여 MPEG-21 내에서 멀티미디어 자원의 저작권 통합 운용을 위한 저작 정보를 쉽고 빠르게 생성할 수 있는 도구가 요구된다. 이에 본 논문은 멀티미디어 자원을 통합 관리하기 위한 REL 문서를 저작하고 표현하며 수정 할 수 있는 저작 도구와 저작된 정보를 운용하는 시스템을 설계 및 구현하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3544-3564
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• 2022

With the development of the NB-IoT (Narrow band Internet of Things) and smart cities, coupled with the emergence of smart smoke sensors, new requirements and issues have been introduced to study on the deployment of sensors in large spaces. Previous research mainly focuses on the optimization of wireless sensors in some monitoring environments, including three-dimensional terrain or underwater space. There are relatively few studies on the optimization deployment problem of smart smoke sensors, and leaving large spaces with obstacles such as libraries out of consideration. This paper mainly studies the deployment issue of smart smoke sensors in large spaces by considering the fire probability of fire areas and the obstacles in a monitoring area. To cope with the problems of coverage blind areas and coverage redundancy when sensors are deployed randomly in large spaces, we proposed an optimized deployment strategy of smart smoke sensors based on the PSO (Particle Swarm Optimization) algorithm. The deployment problem is transformed into a multi-objective optimization problem with many constraints of fire probability and barriers, while minimizing the deployment cost and maximizing the coverage accuracy. In this regard, we describe the structure model in large space and a coverage model firstly, then a mathematical model containing two objective functions is established. Finally, a deployment strategy based on PSO algorithm is designed, and the performance of the deployment strategy is verified by a number of simulation experiments. The obtained experimental and numerical results demonstrates that our proposed strategy can obtain better performance than uniform deployment strategies in terms of all the objectives concerned, further demonstrates the effectiveness of our strategy. Additionally, the strategy we proposed also provides theoretical guidance and a practical basis for fire emergency management and other departments to better deploy smart smoke sensors in a large space.

• 영어어문교육
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• 제1호
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• pp.69-108
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• 1995

Listening comprehension can be defined as a process of an integrative, positive and creative activity through which listeners get the message of speakers' production using linguistic or non-linguistic redundancy as well as linguistic or non-linguistic knowledge. Compared with reading comprehension, it has many difficulties especially for foreigners. while it can be transferred to the other skills: speaking, reading, writing. With this said, listening comprehension can be taught effectively using the following teaching strategies. First. systematic and intensive instruction of segmental phonemes, suprasegmental phonemes and sound changes must be given to remove the difficulties of listening comprehension concerned with the identification of sounds. Second, vocabulary drill through various games and other activities is absolutely needed until words can be unconsciously recognized. Without this, comprehension is almost impossible. Third, instruction of sentence structures is thought to be essential considering grammar is supplementary to listening comprehension and reading comprehension for academic purpose. So grammar translation drills, mechanical drills, meaningful drills and communicative drills should be performed in succession with common or frequently used structures. Fourth, listening activities for overall comprehension should teach how to receive overall meaning of intended messages intact. Linguists and literatures have listed some specific activities as follows: Total Physical Response, dictation, role playing, singing songs, selective listening, picture recognition, list activities, completion, prediction, true or false choice, multiple choice, seeking of specific information, summarizing, problem-solving and decision-making, recognization of relationships between speakers, recognition of mood, attitude and behavior of speakers.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.188-191
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• 2002

To reduce the bit-rate of video sequences by removing temporal redundancy, motion estimation techniques have been developed. However, the high computational complexity of the problem makes such techniques very difficult to be applied to high-resolution applications in a real time environment. For this reason, low computational complexity motion estimation algorithms are viable solutions. If a priori knowledge about the motion of the current block is available before the motion estimation, a better starting point for the search of n optimal motion vector on be selected and also the computational complexity will be reduced. In this paper, we present an adaptive block matching algorithm based on temporal correlations of consecutive image frames that defines the search pattern and the location of initial starting point adaptively to reduce computational complexity. Experiments show that, comparing with DS(Diamond Search) algorithm, the proposed algorithm is about 0.1∼0.5(㏈) better than DS in terms of PSNR and improves as much as 50% in terms of the average number of search points per motion estimation.

• 한국CDE학회논문집
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• 제16권4호
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• pp.249-259
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• 2011

In this paper we present our work on the parameterized construction of virtual drivers' reach motion to seat belt, by using motion capture data. A user can generate a new reach motion by controlling a number of parameters. We approach the problem by using multiple sets of example reach motions and learning the relation between the labeling parameters and the motion data. The work is composed of three tasks. First, we construct a motion database using multiple sets of labeled motion clips obtained by using a motion capture device. This involves removing the redundancy of each motion clip by using PCA (Principal Component Analysis), and establishing temporal correspondence among different motion clips by automatic segmentation and piecewise time warping of each clip. Next, we compute motion blending functions by learning the relation between labeling parameters (age, hip base point (HBP), and height) and the motion parameters as represented by a set of PC coefficients. During runtime, on-line motion synthesis is accomplished by evaluating the motion blending function from the user-supplied control parameters.