• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.454-456
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• 2002

압축 방법에는 크게 손실(lossy)압축과 무손실(lossless)압축으로 나눌 수 있다. 그 중 프랙탈 이미지 압축은 lossy 압축의 한가지 방법으로서 개별적인 화소들에 대한 자료를 저장하기보다는, 영상 생성을 위한 명령이나 방식을 저장하는 방법이다. 특히 이미지의 내에 자기유사성(self-similarity)과 중복성(Redundancy)을 이용하여 관련성을 발견하고 수학적인 공식으로 표현하려는 방식이다. 그러나 이미지를 Domain과 Range로 블록화 한 후 유사한 이미지를 찾아내는 데 걸리는 시간이 상당히 길다. 여기에서는 Domain과 Range의 외곽선의 기울기의 부호를 이용하여 블록을 16가지로 클래스화 하여서, 전체의 Domain 블록을 탐색하는 데 걸리는 시간을 줄이고자 하였다. 전체 탐색을 하는 경우보다 10배 이상의 속도향상을 보였고, 이미지에 따라서는 PSNR 값의 손실도 없음을 보였다.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.10
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• pp.377-382
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• 2014

Analysis techniques of the data over time from the mobile environment and IoT, is mainly used for extracting patterns from the collected data, to find meaningful information. However, analytical methods existing, is based to be analyzed in a state where the data collection is complete, to reflect changes in time series data associated with the passage of time is difficult. In this paper, we introduce a method for analyzing multi-block streaming data(AM-MBSD: Analysis Method for Multi-Block Stream Data) for the analysis of the data stream with multiple properties, such as variability of pattern and large capacitive and continuity of data. The multi-block streaming data, define a plurality of blocks of data to be continuously generated, each block, by using the analysis method of the proposed method of analysis to extract meaningful patterns. The patterns that are extracted, generation time, frequency, were collected and consideration of such errors. Through analysis experiments using time series data.

• Journal of KIISE:Software and Applications
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• v.33 no.7
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• pp.624-635
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• 2006

This paper applies simulated annealing algorithm to the problem of generating a plan for intra-block remarshalling with multiple transfer cranes. Intra-block remarshalling refers to the task of rearranging containers scattered around within a block into certain designated target areas of the block so that they can be efficiently loaded onto a ship. In generating a remarshalling plan, the predetermined container loading sequence should be considered carefully to avoid re-handlings that may delay the loading operations. In addition, the required time for the remarshalling operation itself should be minimized. A candidate solution in our search space specifies target locations of the containers to be rearranged. A candidate solution is evaluated by deriving a container moving plan and estimating the time needed to execute the plan using two cranes with minimum interference. Simulation experiments have shown that our method can generate efficient remarshalling plans in various situations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.11a
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• pp.12-14
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• 2014

본 논문에서는 AZB (All-Zero Block) 검출을 이용한 조기 부호화 단위(Coding Unit, CU) 결정 방법을 제안한다. HEVC 영상 코덱의 하드웨어 구현에서 이산여현변환(DCT)는 많은 부호화 자원을 필요로 하는 과정으로 DCT 수행 이전에 블록 내의 모든 양자화 계수가 0 이 되는 영블록(All-zero Block)을 미리 검출하여 DCT 및 양자화 과정을 생략하고 CU 의 부호화 과정을 조기에 종료함으로써 부호화 복잡도를 크게 감소시키는 방법을 제안한다. 기존의 SAD (Sum of Absolute Difference) 또는 SATD (Sum of Absolute Transform Difference)에 기반하는 AZB 검출 방법은 HEVC 에서 새롭게 추가된 큰 크기의 $16{\times}16$와 $32{\times}32$ DCT 에서 AZB 을 효율적으로 검출할 수 없는 한계가 존재한다. 본 논문에서는 DCT 변환 커널이 하다마드 변환 커널과 또 다른 정규 직교 변환 커널로 분할하여 표현할 수 있는 성질을 이용하여, 부화소 움직임벡터 추정 과정을 통해 생성된 하드마드 변환 계수에 DCT 를 생성하는 변환 커널을 곱하여 DCT 변환 커널을 생성한 후 양자화 계수를 이용하여 CU 단위의 AZB 을 검출하는 방법을 제안한다. 또한 AZB 검출과 움직임 벡터의 크기를 이용하여 현재 CU 의 부호화 과정을 조기에 종료하는 방법을 제안한다. 제안하는 AZB 검출과 CU 조기 종료 부호화 방법을 사용하면 평균적으로 34.7%의 부호화 시간을 감소시켜 부호화 복잡도를 크게 줄일 수 있다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.359-366
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• 2009

MATLAB Autocode generation is a feature that converts a block diagram model in Simulink to a c program. Utilizing this function makes MATLAB/Simulink an integrated developing environment, from controller design to implementation. It can reduce development cost and time significantly. However, this automated process requires high reliability on the software, especially the original Simulink block diagram model. And thus, the verification of the codes becomes important. In this study, a UAV flight program which is generated with Simulink is validated and modified according to DO-178B. As a result of applying the procedures, the final program not only satisfied the functional requirement but is also verified with structural point of view with Decision Coverage 93%, Condition Coverage 95% and MC/DC 90%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.61-67
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• 2016

With the current high distribution rate of smart devices and the recent development of computing technology, user interest in multimedia, such as photos, videos, and so on, has rapidly increased, which is a departure from the simple pattern of information retrieval. Because of these increasing interests, image processing techniques, which generate and process images for diverse applications, are being developed. In entertainment recently, there are some techniques that present a celebrity's image as a mosaic comprising many small images. In addition, studies into the mosaic technique are actively conducted. However, conventional mosaic techniques result in a long processing time as the number of database images increases, because they compare the images in the databases sequentially. Therefore, to increase search efficiency, this paper proposes an algorithm to generate a mosaic image using a discrete cosine transform (DCT) hash. The proposed photo mosaic-generation algorithm is composed of database creation and mosaic image generation. In database creation, it first segments images into blocks with a predefined size. And then, it computes and stores a DCT hash set for each segmented block. In mosaic generation, it efficiently searches for the most similar blocks in the database via DCT hash for every block of the input image, and then it generates the final mosaic. With diverse experimental results, the proposed photo mosaic-creation algorithm can effectively generate a mosaic, regardless of the various types of images and sizes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.786-792
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• 2016

Camellia was jointly developed by Nippon Telegraph and Telephone Corporation and Mitsubishi Electric Corporation in 2000. Camellia specifies the 128-bit message block size and 128-, 192-, and 256-bit key sizes. In this paper, a modified round operation block which unifies a register setting for key schedule and a conventional round operation block is proposed. 16 ROMs needed for key generation and round operation are implemented using only 4 dual-port ROMs. Due to the use of a message buffer, encryption/decryption can be executed without a waiting time immediately after KA and KB are calculated. The suggested block cipher Camellia algorithm is designed using Verilog-HDL, implemented on Virtex4 device and operates at 184.898MHz. The designed cryptographic core has a maximum throughput of 1.183Gbps in 128-bit key mode and that of 876.5Mbps in 192 and 256-bit key modes. The cryptographic core of this paper is applicable to security module of the areas such as smart card, internet banking, e-commerce and satellite broadcasting.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.233-238
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• 2021

Recently, blockchain technology accumulates and stores all transactions. Therefore, in order to verify the contents of all transactions, the data itself is compressed, but the scalability is limited. In addition, since a separate verification algorithm is used for each type of transaction, the verification burden increases as the size of the transaction increases. Existing blockchain cannot participate in the network because it does not become a block sink by using a server with a low specification. Due to this problem, as the time passes, the data size of the blockchain network becomes larger and it becomes impossible to participate in the network except for users with abundant resources. Therefore, in this paper, we are improved transaction as studied the zero knowledge proof algorithm for general operation verification. In this system, the design of zero-knowledge circuit generator capable of general operation verification and optimization of verifier and prover were also conducted.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.142-148
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• 2008

Though a deblocking filter of H.264/AVC provides enhanced image quality by removing blocking artifact on block boundary, the complex filtering operation on this process is a dominant factor of the whole decoding time. In this paper, we designed an ASIP to accelerate deblocking filter operation with the proposed instruction set. We designed a processor based on a MIPS structure with LISA, simulated a deblocking later model, and compared the execution time on the proposed instruction set. In addition, we generated HDL model of the processor through CoWare's Processor Designer and synthesized with TSMC 0.25um CMOS cell library by Synopsys Design Compiler. As the result of the synthesis, the area and delay time increased 7.5% and 3.2%, respectively. However, due to the proposed instruction set, total execution performance is improved by 18.18% on average.

• The KIPS Transactions:PartB
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• v.17B no.6
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• pp.421-428
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• 2010

It takes a long time for the users to view a whole image from the image server under the low-bandwidth internet environments or in case of a big sized image. In this case, as there needs a technique that preferentially transfers a part of image, JPEG2000 offers a ROI(Region-of-Interest) coding. In ROI coding, the users see the thumbnail of image from the server and specifies some regions that they want to see first. And then if an information about the regions are informed to the server, the server preferentially transfers the regions of the image. The existing methods requested a huge time to compute the mask information, but this thesis approximately computes the regions and reduces the creating time of the ROI masks. If each code block is a mixed block which ROI and background are mixed, the proper boundary points should be acquired. Searching the edges of the block, getting the two points on the edge, to get the boundary point inside the code block, the method searches a mid point between the two edge points. The proposed method doesn't have a big difference compared to the existing methods in quality, but the processing time is more speedy than the ones.