• Title/Summary/Keyword: 레지스터

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Symbol Timing Alignment and Combining Technique in Rake Receiver for cdma2000 Systems (cdma2000 시스템용 레이크 수신기에서의 심볼 정렬 및 컴바이닝 기법)

  • Lee, Seong-Ju;Kim, Jae-Seok;Eo, Ik-Su;Kim, Gyeong-Su
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.39 no.1
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    • pp.34-41
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    • 2002
  • In the conventional rake receiver structure for the IS-95 CDMA system, each finger has its own time-deskew buffer or FIFO that aligns the multipath signals to the same timing reference in order to combine symbols. This architecture is not a burden to the rake receiver design mainly because of the small number and size of the buffers. However, the number and size of the buffers are significantly increased in the cdma2000 system which adopts multiple carriers and the small spreading gain for a higher rate in data services. In order to decrease the number of buffers, we propose a new model of the time-deskew buffers, which combines the symbols as well as realigns them at the same time. Our architecture reduces the hardware complexity of the buffers by about more than 60% and 70% compared with the conventional one when we consider each rake receiver has three and four independent fingers, respectively. Moreover, the proposed algorithm is very useful not only to the cdma2000 rake receiver but also to the receiver with many fingers in order to increase the BER performance.

Memory Reduction of IFFT Using Combined Integer Mapping for OFDM Transmitters (CIM(Combined Integer Mapping)을 이용한 OFDM 송신기의 IFFT 메모리 감소)

  • Lee, Jae-Kyung;Jang, In-Gul;Chung, Jin-Gyun;Lee, Chul-Dong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.10
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    • pp.36-42
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    • 2010
  • FFT(Fast Fourier Transform) processor is one of the key components in the implementation of OFDM systems for many wireless standards such as IEEE 802.22. To improve the performances of FFT processors, various studies have been carried out to reduce the complexities of multipliers, memory interface, control schemes and so on. While the number of FFT stages increases logarithmically $log_2N$) as the FFT point-size (N) increases, the number of required registers (or, memories) increases linearly. In large point-size FFT designs, the registers occupy more than 70% of the chip area. In this paper, to reduce the memory size of IFFT for OFDM transmitters, we propose a new IFFT design method based on a combined mapping of modulated data, pilot and null signals. The proposed method focuses on reducing the sizes of the registers in the first two stages of the IFFT architectures since the first two stages require 75% of the total registers. By simulations of 2048-point IFFT design for cognitive radio systems, it is shown that the proposed IFFT design method achieves more than 38.5% area reduction compared with previous IFFT designs.

Efficient Implementation of SVM-Based Speech/Music Classifier by Utilizing Temporal Locality (시간적 근접성 향상을 통한 효율적인 SVM 기반 음성/음악 분류기의 구현 방법)

  • Lim, Chung-Soo;Chang, Joon-Hyuk
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.2
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    • pp.149-156
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    • 2012
  • Support vector machines (SVMs) are well known for their pattern recognition capability, but proper care should be taken to alleviate their inherent implementation cost resulting from high computational intensity and memory requirement, especially in embedded systems where only limited resources are available. Since the memory requirement determined by the dimensionality and the number of support vectors is generally too high for a cache in embedded systems to accomodate, frequent accesses to the main memory occur inevitably whenever the cache is not able to provide requested data to the processor. These frequent accesses to the main memory result in overall performance degradation and increased energy consumption because a memory access typically takes longer and consumes more energy than a cache access or a register access. In this paper, we propose a technique that reduces the number of main memory accesses by optimizing the data access pattern of the SVM-based classifier in such a way that the temporal locality of the accesses increases, fully utilizing data loaded into the processor chip. With experiments, we confirm the enhancement made by the proposed technique in terms of the number of memory accesses, overall execution time, and energy consumption.

Fast Image Pre-processing Algorithms Using SSE Instructions (SSE 명령어를 이용한 영상의 고속 전처리 알고리즘)

  • Park, Eun-Soo;Cui, Xuenan;Kim, Jun-Chul;Im, Yu-Cheong;Kim, Hak-Il
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.2
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    • pp.65-77
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    • 2009
  • This paper proposes fast image processing algorithms using SSE (Streaming SIMD Extensions) instructions. The CPU's supporting SSE instructions have 128bit XMM registers; data included in these registers are processed at the same time with the SIMD (Single Instruction Multiple Data) mode. This paper develops new SIMD image processing algorithms for Mean filter, Sobel horizontal edge detector, and Morphological erosion operation which are most widely used in automated optical inspection systems and compares their processing times. In order to objectively evaluate the processing time, the developed algorithms are compared with OpenCV 1.0 operated in SISD (Single Instruction Single Data) mode, Intel's IPP 5.2 and MIL 8.0 which are fast image processing libraries supporting SIMD mode. The experimental result shows that the proposed algorithms on average are 8 times faster than the SISD mode image processing library and 1.4 times faster than the SIMD fast image processing libraries. The proposed algorithms demonstrate their applicability to practical image processing systems at high speed without commercial image processing libraries or additional hardwares.

Design and Implementation of Feature Catalogue Builder based on the S-100 Standard (S-100 표준 기반 피처 카탈로그 제작지원 시스템의 설계 및 구현)

  • Park, Daewon;Kwon, Hyuk-Chul;Park, Suhyun
    • KIPS Transactions on Software and Data Engineering
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    • v.2 no.8
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    • pp.571-578
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    • 2013
  • The IHO S-100 is a standard on the universal hydorgraphic data model for supporting information services that integrate various data in maritime and provide proper information for safety of vessels. The S-100 is used to develop S-10x product specifications which are standards on guideline for creation and delivery of specific data set in maritime. The product specification for feature-based data such as ENC(Electronic Navigational Chart) data includes a feature catalogue that describes characteristics of features in that feature-based data. The feature catalogue is developed by domain experts with knowledge on data of the target domain. However, it is not feasible to develop a feature catalogue according to the XML schema by manual. In the IHO TSMAD committee meeting, needs of developing technology on building feature catalogue has been discussed. Therefore, we present a feature catalogue builder that is a GUI(Graphic User Interface) system supporting domain experts to build feature catalogues in XML. The feature catalogue builder is developed to connect with the FCD(Feature Concept Dictionary) register in the IHO(International Hydrographic Organization) GI(Geographic Information) registry. Also, it supports domain experts to select proper feature items based on the relationships between register items.

A Bloom Filter Application of Network Processor for High-Speed Filtering Buffer-Overflow Worm (버퍼 오버플로우 웜 고속 필터링을 위한 네트워크 프로세서의 Bloom Filter 활용)

  • Kim Ik-Kyun;Oh Jin-Tae;Jang Jong-Soo;Sohn Sung-Won;Han Ki-Jun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.7 s.349
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    • pp.93-103
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    • 2006
  • Network solutions for protecting against worm attacks that complement partial end system patch deployment is a pressing problem. In the content-based worm filtering, the challenges focus on the detection accuracy and its performance enhancement problem. We present a worm filter architecture using the bloom filter for deployment at high-speed transit points on the Internet, including firewalls and gateways. Content-based packet filtering at multi-gigabit line rates, in general, is a challenging problem due to the signature explosion problem that curtails performance. We show that for worm malware, in particular, buffer overflow worms which comprise a large segment of recent outbreaks, scalable -- accurate, cut-through, and extensible -- filtering performance is feasible. We demonstrate the efficacy of the design by implementing it on an Intel IXP network processor platform with gigabit interfaces. We benchmark the worm filter network appliance on a suite of current/past worms, showing multi-gigabit line speed filtering prowess with minimal footprint on end-to-end network performance.

Implementation of Turbo Decoder Based on Two-step SOVA with a Scaling Factor (비례축소인자를 가진 2단 SOVA를 이용한 터보 복호기의 설계)

  • Kim, Dae-Won;Choi, Jun-Rim
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.39 no.11
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    • pp.14-23
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    • 2002
  • Two implementation methods for SOVA (Soft Output Viterbi Algorithm)of Turbo decoder are applied and verfied. The first method is the combination of a trace back (TB) logic for the survivor state and a double trace back logic for the weight value in two-step SOVA. This architecure of two-setp SOVA decoder allows important savings in area and high-speed processing compared with that of one-step SOVA decoding using register exchange (RE) or trace-back (TB) method. Second method is adjusting the reliability value with a scaling factor between 0.25 and 0.33 in order to compensate for the distortion for a rate 1/3 and 8-state SOVA decoder with a 256-bit frame size. The proposed schemes contributed to higher SNR performance by 2dB at the BER 10E-4 than that of SOVA decoder without a scaling factor. In order to verify the suggested schemes, the SOVA decoder is testd using Xillinx XCV 1000E FPGA, which runs at 33.6MHz of the maximum speed with 845 latencies and it features 175K gates in the case of 256-bit frame size.

A Case Study for Interactive Learning between Visitors and Exhibits in a Natural History Hall Focused on the Discourse Flow and the Modes of Visitors' Own Interactions (관람 대화의 흐름과 상호작용의 양상에 기반한 자연사 전시관의 전시물과 관람객 간 상호작용적 학습 사례 연구)

  • Choi, Moon-Young;Maeng, Seungho;Park, Eun Ji;Jung, Won-Young;Kim, Chan-Jong
    • Journal of The Korean Association For Science Education
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    • v.32 no.7
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    • pp.1251-1268
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    • 2012
  • This study investigated several cases of interactive learning mediated by exhibits in a natural history hall during visits by middle school students. Five visiting cases were selected, in which visitors engaged actively in the interactions between them. Each visiting case was analyzed in terms of visiting discourse register and the modes of interaction in order to understand both visitors' meaning-making processes through the discourse flow and the characteristics of visiting discourse according to the features of exhibits. Results were as follows. The information provided in the exhibits was used as THEMEs in visitors' discourse and the visitors presented their information on the THEMEs as RHEMEs. The visitors made their own meaning for the exhibits by exchanging their information with each other. Interrogative sentences on the exhibit panels allowed visitors to make arguments. Similar exhibits displayed together helped visitors to compare those exhibits. These two features of the exhibits facilitated visitors' meaning-making processes in the natural history hall. The modes of interaction between visitors mediated by the exhibits showed that the information itself from the exhibits as well as visitors' opinion on the exhibits were frequently used as the elements for in-depth cognitive social interactions that allowed the visitors to construct meaning. Based on these results, we discussed that understanding in detail how visitors choose information from exhibits and construct visiting discourse is very important to improve visitors' collaborative science learning at a natural history hall.

The Wet and Dry Etching Process of Thin Film Transistor (박막트랜지스터의 습식 및 건식 식각 공정)

  • Park, Choon-Sik;Hur, Chang-Wu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.7
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    • pp.1393-1398
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    • 2009
  • Conventionally, etching is first considered for microelectronics fabrication process and is specially important in process of a-Si:H thin film transistor for LCD. In this paper, we stabilize properties of device by development of wet and dry etching process. The a-Si:H TFTs of this paper is inverted staggered type. The gate electrode is lower part. The gate electrode is formed by patterning with length of 8 ${\mu}$m${\sim}$16 ${\mu}$m and width of 80${\sim}$200 ${\mu}$m after depositing with gate electrode (Cr) 1500 ${\AA}$under coming 7059 glass substrate. We have fabricated a-SiN:H, conductor, etch-stopper and photo resistor on gate electrode in sequence, respectively. The thickness of these thin films is formed with a-SiN:H (2000 ${\mu}$m), a-Si:H(2000 ${\mu}$m) and n+a-Si:H (500 ${\mu}$m), We have deposited n-a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-stopper pattern. The NPR layer by inverting pattern of upper gate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. In the fabricated TFT, the most frequent problems are over and under etching in etching process. We were able to improve properties of device by strict criterion on wet, dry etching and cleaning process.

The Improvement of Fabrication Process for a-Si:H TFT's Yield (a-Si:H TFT의 수율 향상을 위한 공정 개선)

  • Hur, Chang-Wu
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.6
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    • pp.1099-1103
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    • 2007
  • TFT's have been intensively researched for possible electronic and display applications. Through tremendous engineering and scientific efforts, a-Si:H TFT fabrication process was greatly improved. In this paper, the reason on defects occurring at a-Si:H TFT fabrication process is analyzed and solved, so a-Si:H TFT's yield is increased and reliability is improved. The a-Si:H TFT of this paper is inverted staggered type TFT. The gate electrode is formed by patterning with length of $8{\mu}m{\sim}16{\mu}m$ and width of $80{\sim}200{\mu}m$ after depositing with gate electrode (Cr). We have fabricated a-SiN:H, conductor, etch-stopper and photo-resistor on gate electrode in sequence, respectively. We have deposited n+a-Si:H, NPR(Negative Photo Resister) layer after forming pattern of Cr gate electrode by etch-slower pattern. The NPR layer by inverting pattern of upper Sate electrode is patterned and the n+a-Si:H layer is etched by the NPR pattern. The NPR layer is removed. After Cr layer is deposited and patterned, the source-drain electrode is formed. The a-Si:H TFT made like this has problems at photo-lithography process caused by remains of PR. When sample is cleaned, this remains of PR makes thin chemical film on surface and damages device. Therefor, in order to improve this problem we added ashing process and cleaning process was enforced strictly. We can estimate that this method stabilizes fabrication process and makes to increase a-Si:H TFT's yield.