• Title/Summary/Keyword: efficient coding

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Specification and Simulation Environment for Prototying the Object Model (객체 모델의 프로토파이핑을 위한 명세 및 시물레이션 환경)

  • Jung, Lan;Kim, Jung-A;Moon, Chung-Ryeal;Kim, Jung-Doo
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.5
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    • pp.1243-1256
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    • 1997
  • Object modeling has been cinsidered as an efficient technique for eleciting user requirements and communicat-ing between developers and customers. But model itself is not easy to understand what recult will be after coding and whether it will be meet with the requirements of customers. In this paper, we developed the envuroment for visualization of object model for validating with rewuirnent at the early stage. Therefore, we defined correct and complete rules which can transform the object model.the delierables of Shler/Mellor's method, into a for-mal specification language of VDM(Vienna Development Methods) with a mathematical basis. This basis provides the means of proving that a specification is realizable and proving properties of a system.Therefore.the completeness, preciceness of object model can be verified by proving the transformed VDM specification and prototyping by constructing a visualization supporting enviroment.

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Efficient Expression, Purification, and Characterization of a Novel FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus in Pichia pastoris

  • Yang, Yufeng;Huang, Lei;Wang, Jufang;Wang, Xiaoning;Xu, Zhinan
    • Journal of Microbiology and Biotechnology
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    • v.24 no.11
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    • pp.1516-1524
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    • 2014
  • Flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) can utilize a variety of external electron acceptors and also has stricter substrate specificity than any other glucose oxidoreductases, which makes it the ideal diagnostic enzyme in the field of glucose biosensors. A gene coding for a hypothetical protein, similar to glucose oxidase and derived from Aspergillus terreus NIH2624, was overexpressed in Pichia pastoris GS115 under the control of an AOX1 promoter with a level of 260,000 U/l in the culture supernatant after fed-batch cultivation for 84 h. After a three-step purification protocol that included isopropanol precipitation, affinity chromatography, and a second isopropanol precipitation, recombinant FAD-GDH was purified with a recovery of 65%. This is the first time that isopropanol precipitation has been used to concentrate a fermentation supernatant and exchange buffers after affinity chromatography purification. The purified FAD-GDH exhibited a broad and diffuse band between 83 and 150 kDa. The recombinant FAD-GDH was stable across a wide pH range (3.5 to 9.0) with maximum activity at pH 7.5 and $55^{\circ}C$. In addition, it displayed very high thermal stability, with a half-life of 82 min at $60^{\circ}C$. These characteristics indicate that FAD-GDH will be useful in the field of glucose biosensors.

A Study on Enhancement of Digital Image Performance Using Dual Tree Wavelet Transformation in Non-separable Image Processing (비분리 영상처리에서 이중 트리 웨이브렛 변환을 사용한 디지털 영상 성능 개선에 관한 연구)

  • Lim, Joong-Hee;Jee, Inn-Ho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.1
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    • pp.65-74
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    • 2012
  • In this paper, we explore the application of 2-D dual-tree discrete wavelet transform (DDWT), which is a directional and redundant transform, for image coding. DDWT introduces limited redundancy and allows the transform to provide approximate shift invariance and directionally selective filters while preserving the usual properties of perfect reconstruction and computational efficiency with good well-balanced frequency responses. Also, quincunx lattice yields a non separable 2D-wavelet transform, which is also symmetric in both horizontal and vertical direction. And non-separable wavelet transformation can generate sub-images of multiple degrees rotated versions. The proposed 2-D non-separable DDWT can provide efficient approximation for directional features of images schemes, such as edges and contours in images that are not aligned with the horizontal or vertical direction. Finally, non-separable image processing using DDWT services good performance.

Cooperative Diversity Performance Using Duo-Binary Turbo Codes (Duo-Binary 터보 부호를 이용한 협동 다이버시티 성능 분석)

  • Yeo, Sung-Moon;Kim, Soo-Young
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.46 no.2
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    • pp.38-45
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    • 2009
  • In this paper, we propose an efficient cooperative diversity technique, which partition the codewords of each mobile and transmit portions of each codeword through independent fading channels using duo-binary turbo codes. A coded diversity technique can achieve high cooperative diversity gain by decoding and transmitting of the re-encoded signal, while this can also cause high performance degradation due to failure of the decoding. In this paper, we introduce various coded diversity technique using duo-binary turbo codes which are defined as channel coding schemes in the IEEE WiMax specification, and also demonstrate performance simulation results with the analysis. We also propose a cooperative diversity technique using rate-compatible duo-binary turbo codes, where user terminals with different parity symbols cooperate each other. Simulation results investigated in this paper reveal that the proposed scheme show high diversity gain at a reasonal SNR range.

High-speed Radix-8 FFT Structure for OFDM (OFDM용 고속 Radix-8 FFT 구조)

  • Jang, Young-Beom;Hur, Eun-Sung;Park, Jin-Su;Hong, Dae-Ki
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.5
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    • pp.84-93
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    • 2007
  • In this paper, a Radix-8 structure for high-speed FFT is propose. Main block of the proposed FFT structure is Radix-8 DIF(Decimation In Frequency) butterfly. Even throughput of the Radix-8 FFT is twice than that of the Radix-4 FFT, implementation area of the Radix-8 is larger than that of Radix-4 FFT. But, implementation area of the proposed Radix-8 FFT was reduced by using DA(Distributed Arithmetic) for multiplication. For comparison, the 64-point FFT was implemented using conventional Radix-4 butterfly and proposed Radix-8 butterfly, respectively. The Verilog-HDL coding results for the proposed FFT structure show 49.2% cell area increment comparison with those of the conventional Radix-4 FFT structure. Namely, to speed up twice, 49.2% of area cost is required. In case of same throughput, power consumption of the proposed structure is reduced by 25.4%. Due to its efficient processing scheme, the proposed FFT structure can be used in large size of FFT like OFDM Modem.

A Fast Coeff_token Decoding Method for Efficient Implimentation of H.264/AVC CAVLC Decoder (효율적인 H.264/AVC CAVLC 복호화기 구현을 위한 고속 Coeff_token 복원 방식)

  • Moon, Yong-Ho;Park, Tae-Hee
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.5
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    • pp.35-42
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    • 2008
  • In this paper, we propose a fast coeff_token decoding method based on the re-constructed VLCT. Since the conventional decoding method is still based on large memory accesses, it is not suitable for the multimedia services such as PMP, PMB, DVH-H where fast decoding and low power consumption are required. Based on the analysis for the codeword structure, new structure of the codeword and the corresponding memory architecture are developed in this paper. The simulation results show that the proposed algorithm achieves memory access saving from 10% to 57%, compared to the conventional decoding method. This meant that the issues of tow power consumption and high speed decoding can be resolved without video-quality and coding efficiency degradation.

ECG Signal Compression using Feature Points based on Curvature (곡률을 이용한 특징점 기반 심전도 신호 압축)

  • Kim, Tae-Hun;Kim, Sung-Wan;Ryu, Chun-Ha;Yun, Byoung-Ju;Kim, Jeong-Hong;Choi, Byung-Jae;Park, Kil-Houm
    • Journal of the Korean Institute of Intelligent Systems
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    • v.20 no.5
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    • pp.624-630
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    • 2010
  • As electrocardiogram(ECG) signals are generally sampled with a frequency of over 200Hz, a method to compress diagnostic information without losing data is required to store and transmit them efficiently. In this paper, an ECG signal compression method, which uses feature points based on curvature, is proposed. The feature points of P, Q, R, S, T waves, which are critical components of the ECG signal, have large curvature values compared to other vertexes. Thus, these vertexes are extracted with the proposed method, which uses local extremum of curvatures. Furthermore, in order to minimize reconstruction errors of the ECG signal, extra vertexes are added according to the iterative vertex selection method. Through the experimental results on the ECG signals from MIT-BIH Arrhythmia database, it is concluded that the vertexes selected by the proposed method preserve all feature points of the ECG signals. In addition, they are more efficient than the AZTEC(Amplitude Zone Time Epoch Coding) method.

An Adaptive De-blocking Algorithm in Low Bit-rate Video Coding (저 비트율 비디오를 위한 적응적 블록킹 현상 제거 기법)

  • 김종호;김해욱;정제창
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.4C
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    • pp.505-513
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    • 2004
  • Most video codecs including the international standards use the block-based hybrid structure for efficient compression. But for low bit-rate applications such as video transmission through wireless channels, the blocking artifacts degrade image qualify seriously. In this paper, we propose an adaptive de-blocking algorithm using characteristics of the block boundaries. Blocking artifacts contain the high frequency components near the block boundaries, therefore the lowpass filtering can remove them. However, simple lowpass filtering results into blurring by removing important information such as edges. To overcome this problem, we determine the modes depending upon the characteristics of pixels adjacent to block boundary then proper filter is applied to each area. Simulation results show that proposed method improves de-blocking performance compared to that of MPEG-4.

Turbo-coded STC schemes for an integrated satellite-terrestrial system for cooperative diversity (협동 다이버시티 이득을 위한 위성-지상간 통합망에서의 터보 부호화된 시공간 부호)

  • Park, Un-Hee;Kim, Soo-Young;Kim, Hee-Wook;Ahn, Do-Seob
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1A
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    • pp.62-70
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    • 2010
  • In this paper, we evaluate the performance of various diversity techniques which can contribute to provide efficient multimedia broadcasting services via hybrid/integrated satellite and terrestrial network. Space-time coding (STC) can achieve the diversity gain in a multi-path environment without additional bandwidth requirement. Recent study results reported that satellite systems can achieve high diversity gains by appropriate utilization of STC and/or forward error correction schemes. Based on these previous study results, we present various cooperative diversity techniques by combining STC and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system. The satellite and several terrestrial repeaters operate in unison to send the encoded signals, so that receiver may realize diversity gain. The results demonstrated in this paper can be utilized in future system implementation.

An Efficient and Fair Substream Allocation Method for a Distributed Video Streaming System using Multiple Substreams (다수의 부스트림을 이용한 분산 비디오 스트리밍 시스템을 위한 공정하고 효율적인 부스트림 할당 기법)

  • Park, Jae-Sung
    • The KIPS Transactions:PartC
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    • v.19C no.2
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    • pp.145-148
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    • 2012
  • In a distributed streaming system using an advanced coding scheme that encodes a video into multiple substreams, the capacity of the system depends on the amount of contribution of participating peers. Thus, an incentive mechanism for peers to contribute voluntarily is needed to increase system capacity. In addition, since peers are not only a provider but also a consumer in the system (i.e. prosumer), the overall capacity of the system must be allocated fairly among the peers while it must be allocated in a way that can maximize the net quality of experience of peers to increase system efficiency. In this paper, we propose a substream allocation method to solve the problems taking an optimization approach. Unlike the other optimization approaches, the proposed method is verified quantitatively in a simulation study that it can use the capacity of video streaming system efficiently while allocating fair amount of substreams among peers because it considers explicitly the prosumer characteristics of peers.