• ETRI Journal
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• 제34권2호
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• pp.256-259
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• 2012

The double-base number system has been used in digital signal processing systems for over a decade because of its fast inner product operation and low hardware complexity. This letter proposes an innovative multiplier architecture using hybrid operands. The multiplier can easily be linked to flash analog-to-digital converters or digital systems through a double-base number encoder (DBNE) for realtime signal processing. The design of the DBNE and the multiplier enable faster digital signal processing and require less hardware resources compared to the binary processing method.

• 디지털산업정보학회논문지
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• 제12권1호
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• pp.43-50
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• 2016

This paper is on an acoustic echo canceller solving the double-talk problem by using the blind signal separation technology. The acoustic echo canceller may be deteriorated or diverged during the double-talk period. So we use the blind signal separation to detect the double talking by separating the near-end speech signal from the mixed microphone signal. The blind signal separation extracts the near-end signal from dual microphones by the iterative computations using the 2nd order statistical character in the closed reverberation environment. By this method, the acoustic echo canceller operates irrespective of the double-talking. We verified performances of the proposed acoustic echo canceller in the computer simulations. The results show that the acoustic echo canceller with this algorithm detects the double-talk periods well, and then operates stably without diverging of the coefficients after ending the double-talking. The merits are in the simplicity and stability.

• 한국광학회지
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• 제21권3호
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• pp.91-96
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• 2010

디지털 홀로그램을 이용하여 상을 재생 할 때 재생상의 크기는 재생거리와 파장의 함수이다. 이러한 재생거리와 파장 의존성을 제거하기 위하여 이중푸리에변환법이 제안되었고, 이중푸리에변환을 이용하면 일정 크기의 재생상을 얻을 수 있다. 일반적으로 사용된 광원의 파장보다 큰 단차의 높낮이 측정은 단일파장 디지털 홀로그래픽 방식으로 측정이 가능하지 않기 때문에 2 파장홀로그래피가 제안되었는데, 두 파장에서 얻어진 각각의 재생상의 크기가 같아야 하는 제약이 있다. 본 연구에서는 투과 및 반사형 2 파장 디지털 홀로그래픽 현미경을 이용하여 각각의 파장별로 홀로그램을 촬영하고 이중푸리에변환을 이용하여 재생함으로써 두개의 파장에서 얻어진 재생상의 크기를 같게 만들어 주는 과정 없이 단차를 가진 샘플의 3차원 높낮이 측정을 할 수 있었다.

• 디지털산업정보학회논문지
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• 제8권2호
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• pp.131-143
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• 2012

This paper introduces the double-density discrete wavelet transform using 3 direction separable processing method, which is a discrete wavelet transform that combines the double-density discrete wavelet transform and quincunx sampling method, each of which has its own characteristics and advantages. The double-density discrete wavelet transform is nearly shift-invariant. But there is room for improvement because not all of the wavelets are directional. That is, although the double-density DWT utilizes more wavelets, some lack a dominant spatial orientation, which prevents them from being able to isolate those directions. The dual-tree discrete wavelet transform has a more computationally efficient approach to shift invariance. Also, the dual-tree discrete wavelet transform gives much better directional selectivity when filtering multidimensional signals. But this transformation has more cost complexity Because it needs eight digital filters. Therefor, we need to hybrid transform which has the more directional selection and the lower cost complexity. A solution to this problem is a the double-density discrete wavelet transform using 3 direction separable processing method. The proposed wavelet transformation services good performance in image and video processing fields.

• 제어로봇시스템학회논문지
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• 제20권6호
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• pp.625-630
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• 2014

Asynchronous digital circuits working in military and space environments are often subject to the adverse effects of radiation faults. In this paper, we propose a new hardening technique against radiation faults. The considered digital system has the structure of DMR (Double Modular Redundancy), in which two sub-systems conduct the same work simultaneously. Based on the output feedback, the proposed scheme diagnoses occurrences of radiation faults and realizes immediate recovery to the normal behavior by overriding parts of memory bits of the faulty sub-system. As a case study, the proposed control scheme is applied to an asynchronous dual ring counter implemented in VHDL code.

• 한국멀티미디어학회논문지
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• 제19권6호
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• pp.1043-1051
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• 2016

In this paper, double encryption technique of binary image using random phase mask and 2-step phase-shifting digital holography is proposed. After phase modulating of binary image, firstly, random phase mask to be used as key image is generated through the XOR operation with the binary phase image. And the first encrypted image is encrypted again through the fresnel transform and 2-step phase-shifting digital holography. In the decryption, simple arithmetic operation and inverse Fresnel transform are used to get the first decryption image, and second decryption image is generated through XOR operation between first decryption image and key image. Finally, the original binary image is recovered through phase modulation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.213-216
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• 2002

A double-heterostructure AIGaAs/GaAs PHEMT (Pseudomorphic High Electron Mobility Transistor) using digital recess has been successfully realized. Futhermore, the differences of gm,nax, fT, fmax between two samples are as low as 0.62%, 1.58% and 2.56 % respectively. Experimental results are presented demonstrating the etch rate and Process invariability with respect to hydrogen peroxide and acid exposure times with uniformity among devices on a sample.

• 한국전자파학회논문지
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• 제15권11호
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• pp.1069-1074
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• 2004

본 논문에서는 직렬 inter-digital 커패시터와 이중 병렬 인덕티브 쇼트 스텁으로 구성된 double negative(DNG) 전송 선로를 설계하였다. 이러한 DNG 전송 선로는 특정한 주파수 이상에서는 double positive(DPS) 전송 선로의 특성을 가진다. 다시 말해서, 설계된 전송 선로는 DNG와DPS전송 선로의 특성을 주파수에 따라서 동시에 가진다. 누설파 대역에서의 DPS/DNG 전송 선로는 주파수 스캐닝 안테나로 이용되어 질 수 있다. 대칭 누설파 안테나의 분산 특성과 원거리 방사 패턴을 모의실험하였고 제작 및 측정하였다. 모의실험 결과는 측정결과와 대략 일치하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.234-237
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• 2007

Road networks are important geospatial databases for various GIS (Geographic Information System) applications. Road digital maps may contain geometric spatial errors due to human and scanning errors, but manually updating roads information is time consuming. In this paper, we developed a new road features updating methodology using from multispectral high-resolution satellite image and pre-existing vector map. The approach is based on initial seed point generation using line segment matching and a modified double snake algorithm. Firstly, we conducted line segment matching between the road vector data and the edges of image obtained by Canny operator. Then, the translated road data was used to initialize the seed points of the double snake model in order to refine the updating of road features. The double snake algorithm is composed of two open snake models which are evolving jointly to keep a parallel between them. In the proposed algorithm, a new energy term was added which behaved as a constraint. It forced the snake nodes not to be out of potential road pixels in multispectral image. The experiment was accomplished using a QuickBird pan-sharpened multispectral image and 1:5,000 digital road maps of Daejeon. We showed the feasibility of the approach by presenting results in this urban area.

• 전기전자학회논문지
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• 제2권2호
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• pp.309-315
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• 1998

본 논문에서는 광대역 종합 통신망 응용을 위한 8b 52 MHz CMOS 서브레인징 (subranging) A/D 변환기 (analog-to-digital converter : ADC)를 제안한다. 제안된 A/D 변환기는 새로운 방식의 동작 순서 기법을 사용하여 기존의 이중 채널 서브레인징 A/D 변환기 동작에 존재하는 홀딩 시간 (holding time)을 제거함으로써 신호 처리 속도 (throughput rate)를 50 % 향상시켰다. 또한, 하위 비트 A/D 변환기에서의 잔류 전압처리에 인터폴레이션 (interpolation) 기법을 이용하여 A/D 변환기의 비교기에 사용되는 프리앰프의 수를 50 % 수준으로 줄임으로써 면적을 감소시켰다. 시제품 A/D 변환기는 0.8 um n-well double-poly double-metal CMOS 공정으로 제작되었고, 측정 결과, 5 V 전원 전압과 52 MHz 샘플링 주파수에서는 230 mW, 3 V 전원 전압 및 40 MHz 샘플링 주파수에서는 60 mW의 전력을 각각 소모한다.