• Journal of Korean Society of Industrial and Systems Engineering
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• v.28 no.3
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• pp.36-41
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• 2005

페트리 네트(Petri Nets)는 이산 사건 시스템을 모델링할 수 있는 그래픽하고, 수학적인 도구이다. 본 연구는 유연제조 시스템을 확률적인 페트리 네트(Stochastic Petri Nets)중의 하나인 임베디드 마코프 체인(Embeded Markov Chain)에 도입하고, 임베디드 마코프 체인의 방법 중에 하나인 일반화된 확률적 페트리 네트(Generalized Stochastic Perti Nets)에 적용시켰다. 그리고 결과치의 정확성을 알아내기 위하여, 페트리 네트 시뮬레이션과 아레나를 사용하여 실행하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.575-584
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• 2002

This paper presents a novel DCT-based embedded zero-tree coding and optimal bit allocation algorithm for image sequence coding. In order to fully utilize the structure of the conventional standard coding algorithm and improve the coding efficiency, motion estimation and compensation(ME/MC)-DCT hybrid coding structure and a modified zero-tree coding algorithm are applied. After the rearrangement DCT coefficients into pyramidal structure according to their significance on the decoded image quality, the modified embedded zero-tree coding is performed on layered coefficients. Moreover, for a given overall bit rates, a new optimal bit control scheme is proposed to achieve the best decoded image quality in the consecutive frames. The rate control scheme can also provide the equal quality of decoded image with the control of bit rate and distortion for each frame. The various simulation results are provided to evaluate the coding performance of the proposed scheme.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.91-94
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• 2001

본 논문에서는 멀티웨이브릿 필터뱅크를 이용한 임베디드 제로 트리 구조(embedded zero tree structure)의 영상 압축방법을 제안한다. 본 논문에서 사용한 멀티웨이브릿 함수는 근사화 차수가 2인 새로운 방법의 DGHM 멀티웨이브릿을 사용하였으며, 영상을 부호화하기 위하여 임베디드 제로 트리 구조의 코딩기법을 사용한다. 높은 근사화 차수를 갖는 멀티웨이브릿 필터는 보다 우수한 에너지 압축 효과를 가지게 된다. 따라서 본 논문에서는 우수한 에너지 압축 효과는 내기 위하여 수학적으로 정립이 된 근사화 차수가 2인 DGHM 멀티웨이브릿을 영상압축에 사용한다. 또한 기존의 멀티웨이브릿 필터들보다 높은 성능을 갖는 DGHM 멀티스케일링 및 멀티웨이브릿 필터를 구성하여 영상을 완전복원이 되도록 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4531-4535
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• 2011

In this paper, USN(Ubiquitous Sensor Network) is used in the structure of the tree routing was implemented in embedded systems. Tree Routing in the USN to the sink node to transmit sensor data is one of the techniques. When routing, sensor data is transmitted based on pre-defined ID according hop number. In order to have optimal routing path, the current state of the wireless sector and the sensor node informations were used. Also, received sensor data and the results of the tree routing by implementing an embedded system. This embedded system can be applied to a portable sensor information collecting system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.3
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• pp.55-62
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• 2012

EZW, also known as Embedded Zerotree Wavelet, is a technique that allows transforming original images into wavelet, then again compressing images using the transformed data. This algorithm demonstrates a simple structure and remarkable effectiveness. This paper has reformed the EZW to improve a compression efficiency. Fundamentally, EZW evaluates the priority level of wavelet-transformed data and stores them into four different categories considering the priority level of the data as well as their location information. The four categories are represented as the symbols P, N, Z, and T. Here, P and N correspond to the volume of data and the priority level whereas Z and T show the location information of data. Each letter is stored through the process of dominant pass. However, here is when the data of Z and T are stored redundantly which lead to unnecessary increase of data volume. In this paper, we propose a modified version of Embedded Zerotree Wavelet algorithm, which is designed to efficiently reduce the volume of redundantly stored data using four additionally inserted symbols. We name it EEZW, Extended Embedded Zerotree Wavelet. The proposed algorithm demonstrates the efficiency verified by a number of image and confirms an outstanding result through the PSNR(Peak Signal To Noise Rate) values, which measure their quality of images.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.63-74
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• 2005

The telematics device, which is a typical embedded system on the transportation or vehicle, requires the embedded spatial DBMS based on RTOS (Real Time Operating System) for processing the huge spatial data in real time. This spatial DBMS can be developed very easily by SQL3 functions of the ORDBMS such as UDT (user-defined type) and UDF (user-defined function). However, developing index suitable for the embedded spatial DBMS is very difficult. This is due to the fact that there is no built-in SQL3 functions to construct spatial indexes. In this study, we compare and analyze both Generalized Search Tree and Relational Indexing methods which are suggested as common ways of developing User-Defined Indexes nowadays. Two implementations of R-Tree based on each method were done and region query performance test results were evaluated for suggesting a suitable indexing method of an embedded spatial DBMS, especially for telematics devices.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.495-496
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• 2008

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.1-11
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• 2015

Recently, NAND flash memories are used for storage devices because of fast access speed and low-power. However, applications of FTL on low power computing devices lead to heavy workloads which result in a memory requirement and an implementation overhead. Consequently, studies of B+-Tree on embedded devices without the FTL have been proposed. The studies of B+-Tree are optimized for performance of inserting and updating records, considering to disadvantages of the NAND flash memory that it can not support in-place update. However, if a general garbage collection method is applied to the previous studies of B+-Tree, a performance of the B+-Tree is reduced, because it generates a rearrangement of the B+-Tree by changing of page positions on the NAND flash memory. Therefor, we propose a novel garbage collection method which can apply to the B+-Tree based on the NAND flash memory without the FTL. The proposed garbage collection method does not generate a rearrangement of the B+-Tree by using a block information table and a proxy block. We implemented the B+-Tree and ${\mu}$-Tree with the proposed garbage collection on physical devices with the NAND flash memory. In experiment results, the proposed garbage collection scheme compared to greedy algorithm garbage collection scheme increased the number of inserted keys by up to about 73% on B+-Tree and decreased elapsed time of garbage collection by up to about 39% on ${\mu}$-Tree.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.8
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• pp.48-54
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• 1999

A new method for wavelet embedded image coding is presented extending the bases of the Shapiro's algorithm by incorporating edge detection, zerotree scheme, and classified VQ(CVQ). Generally edges in the image are regarded an visually important components and the previous literatures have proved that significant coefficients in wavelet transform domain correspond to the edges in spatial domain. Hence, by identifying the edge elements, the significant coefficient can be easily detected in wavelet domain without investigating descendant coefficients across layer. Hierarchical trees for the significant components are organized, and then CVQ method is applied to these trees. Since the significant information has higher priority in transmission, the simulation shows that our coder provides a superior performance over the conventional method and can be successfully applied to the application areas that require of progressive transmission.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1384-1385
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• 2008

본 논문에서는 내장된 수동형 트리플렉서와 듀얼 밴드/트라이모드 RF 모듈을 PCB에 내장시켜서 북미향 CDMA용 부품으로 제작하였다. 수동형 트리플렉서는 모든 수동 소자들을 다층 PCB 기판 안에 내장시키고 그 위에 GPS용 SAW 대역통과필터를 이용하여 설계 및 제작하였다. 8개의 인덕터와 커패시터로 이루어진 수동 회로는 다이플렉서와 병렬 공진기, 임피던스 매칭 회로로 구성되어 있다. CDMA용 듀얼밴드/트라이모드 RF 모듈은 트리플렉서와 CDMA, PCS용 듀플렉서를 테스트 보드 위에 조합하여 제작하였다. 측정된 주파수 특성들은 시뮬레이션 값과 비교적 일치하였다. 트리플렉서와 듀얼 밴드/트라이모드 RF 모듈은 각기 $3{\times}4mm^2$와 ${7\times}7mm^2$의 작은 크기였다. 설계 및 제작된 소자들은 고성능과 경박단소화, 저가화 등의 이점이 있기 때문에, 북미향 CDMA용 단말기의 응용부품에 적용될 수 있을 것으로 예상된다.