• Title/Summary/Keyword: spectral compensation

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A Helicopter-borne Pulse Doppler Radar Signal Processor Development (헬기탑재 펄스 도플러 레이다 신호처리기 개발)

  • Kwag, Young-Kil;Jeun, In-Pyung;Choi, Min-Su;Hwang, Gwang-Yeon;Lee, Kang-Hoon;Lee, Jae-Ho
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.443-446
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    • 2005
  • This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter

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A Helicopter-borne Pulse Doppler Radar Signal Processor Development using High Speed Multi-DSP (고속 Multi-DSP를 이용한 헬기탑재 펄스 도플러 레이다 신호처리기 개발)

  • Kwag, Young-Kil;Choi, Min-Su;Jeun, In-Pyung;Hwang, Gwang-Yeon;Lee, Kang-Hoon;Lee, Jae-Ho
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2005.11a
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    • pp.23-28
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    • 2005
  • An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter.

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Improvement of Bit Error Rate of 16×40 Gbps NRZ-formated WDM Signals over 1,000km NZ-DSF using MSSI with Optimal Parameters (1,000km의 비 영 분산 천이 광섬유로 구성된 WDM 시스템에서 최적 파라미터를 갖는 MSSI를 이용한 NRZ 형식의 16×40 Gbps WDM 신호의 비트 에러율 개선)

  • Lee, Young Kyo
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.3
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    • pp.111-119
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    • 2010
  • In this paper the numerical methods of finding out the optimal position of optical phase conjugator (OPC) and the optimal fiber dispersion are proposed, which are able to effectively compensate overall channels in $16{\times}40$ Gbps WDM system. And the compensation characteristics in the system with two induced optimal parameters are compared with those in the system with the currently used mid-span spectral inversion (MSSI) in order to confirm the availability of the proposed methods. It is confirmed that the reception performances are largely improved in the system with the induced optimal parameters than in the system with MSSI through the analyzing the eye opening penalty (EOP) and bit error rate (BER) characteristics. It is also confirmed that two optimal parameters depend on each other, but are less related with the procedural problem about the first optimal value among these parameters.

EFFICIENT IHS BASED IMAGE FUSION WITH 'COMPENSATIVE' MATRIX CONSTRUCTED BY SIMULATING THE SCALING PROCESS

  • Nguyen, TienCuong;Kim, Dae-Sung;Kim, Yong-Il
    • Proceedings of the KSRS Conference
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    • v.2
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    • pp.639-642
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    • 2006
  • The intensity-hue-saturation (IHS) technique has become a standard procedure in image analysis. It enhances the colour of highly correlated data. Unfortunately, IHS technique is sensitive to the properties of the analyzed area and usually faces colour distortion problems in the fused process. This paper explores the relationship of colour between before and after the fused process and the change in colour space of images. Subsequently, the fused colours are transformed back into the 'simulative' true colours by the following steps: (1) For each pixel of fused image that match with original pixel (of the coarse spectral resolution image) is transformed back to the true colour of original pixel. (2) The value for interpolating pixels is compensated to preserve the DN ratio between the original pixel and it's vicinity. The 'compensative matrix' is constructed by the DN of fused images and simulation of scaling process. An illustrative example of a Landsat and SPOT fused image also demonstrates the simulative true colour fusion methods.

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A Feed-forward Method for Reducing Current Mismatch in Charge Pumps (전하 펌프의 전류 부정합 감소를 위한 피드포워드 방식)

  • Lee, Jae-Hwan;Jeong, Hang-Geun
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.46 no.1
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    • pp.63-67
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    • 2009
  • Current mismatch in a charge pump causes degradation in spectral purity of the phase locked loops(PLLs), such as reference spurs. The current mismatch can be reduced by increasing the output resistance of the charge pump, as in a cascoded output stage. However as the supply voltage is lowered, it is hard to stack transistors. In this paper, a new method for reducing the current mismatch is proposed. The proposed method is based on a feed-forward compensation for the channel length modulation effect of the output stage. The new method has been demonstrated through simulations on typical $0.18{\mu}m$ CMOS circuits.

Development of Audio Melody Extraction and Matching Engine for MIREX 2011 tasks

  • Song, Chai-Jong;Jang, Dalwon;Lee, Seok-Pil;Park, Hochong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2012.07a
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    • pp.164-166
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    • 2012
  • In this paper, we proposed a method for extracting predominant melody of polyphonic music based on harmonic structure. Harmonic structure is an important feature parameter of monophonic signal that has spectral peaks at the integer multiples of its fundamental frequency. We extract all fundamental frequency candidates contained in the polyphonic signal by verifying the required condition of harmonic structure. Then, we combine those harmonic peaks corresponding to each extracted fundamental frequency and assign a rank to each after calculating its harmonic average energy. We run pitch tracking based on the rank of extracted fundamental frequency and continuity of fundamental frequency, and determine the predominant melody. For the query by singing/humming (QbSH) task, we proposed Dynamic Time Warping (DTW) based matching engine. Our system reduces false alarm by combining the distances of multiple DTW processes. To improve the performance, we introduced the asymmetric sense, pitch level compensation, and distance intransitiveness to DTW algorithm.

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BER Performance Improvement of Data-Recycling Equalizer in Time-varing Fading Mobile Communication Channel (시변 페이딩 이동무선채널에서 Data-Recycling 등화기에 의한 BER 성능 개선)

  • Kim, Nam-Yong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.6
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    • pp.581-588
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    • 1997
  • Time-variant mobile radio fading channels distort amplitude, frequency and phase of a transmitted signal. On channels that have time-variant spectral nulls, the conventional equalizers which have low convergence speed and high sensitiveness to phase distortion yields very poor error rate performance. In this paper, the performance of a combined structure with the data-recycling algorithm and fractionally spaced equalizer (FSE) has been investigated on time-variant mobile radio fading channels through computer simulations and compared to other kinds of equalizers. The results show that the data-recycling FSE has excellent capabilities for tracking rapidly time-variant mobile channels and effective compensation for phase distortion.

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The Compensation of the Energy Dependence of TLD (열형광선량계(熱螢光線量計)의 에너지의존성(依存性) 보상(補償))

  • Park, Myeong-Hwan;Lee, Joon-Il;Kwon, Duk-Moon
    • Journal of radiological science and technology
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    • v.16 no.2
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    • pp.51-60
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    • 1993
  • The $CaSO_4$ : Tm-PTFE TLDs have been prepared and their energy dependences of TL intensity to X-rays have been investigated. The dose dependence of the prepared $CaSO_4$ : Tm-PTFE TLDs is linear within the range of $100{\mu}Gy-10Gy$ for X-rays and gamma rays. The spectral peaks of TL emission spectrum are at about 350nm and 475nm. The fading rate of the main peak has been found to be about 2% for 30days when $CaSO_4$ : Tm-PTFE TLDs stored in the dark room at room temperature. The energy dependence of $CaSO_4$ : Tm-PTFE TLD has been compensated by combining the TL responses of one bare TLD and five TLDs filtered with 1.0mm Al, 0.2mm Cu, 0.5mm Cu, 1.5mm Cu, 2.0mm Pb respectively. The determined correction coefficients for filter combination are $a_0=0.078,\;a_1=-0.009,\;a_2=-0.235,\;a_3=0.588,\;a_4=0.568\;and\;a_5=0.180$ respectively. From the results of these studies, the prepared TLD badge of six dosimeter combination may be useful as a radiation dosimeter for personal and environmental monitoring.

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Fire Severity Mapping Using a Single Post-Fire Landsat 7 ETM+ Imagery (단일 시기의 Landsat 7 ETM+ 영상을 이용한 산불피해지도 작성)

  • 원강영;임정호
    • Korean Journal of Remote Sensing
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    • v.17 no.1
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    • pp.85-97
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    • 2001
  • The KT(Kauth-Thomas) and IHS(Intensity-Hue-Saturation) transformation techniques were introduced and compared to investigate fire-scarred areas with single post-fire Landsat 7 ETM+ image. This study consists of two parts. First, using only geometrically corrected imagery, it was examined whether or not the different level of fire-damaged areas could be detected by simple slicing method within the image enhanced by the IHS transform. As a result, since the spectral distribution of each class on each IHS component was overlaid, the simple slicing method did not seem appropriate for the delineation of the areas of the different level of fire severity. Second, the image rectified by both radiometrically and topographically was enhanced by the KT transformation and the IHS transformation, respectively. Then, the images were classified by the maximum likelihood method. The cross-validation was performed for the compensation of relatively small set of ground truth data. The results showed that KT transformation produced better accuracy than IHS transformation. In addition, the KT feature spaces and the spectral distribution of IHS components were analyzed on the graph. This study has shown that, as for the detection of the different level of fire severity, the KT transformation reflects the ground physical conditions better than the IHS transformation.

Differences on specified and actual concrete strength for buildings on seismic zones

  • De-Leon-Escobedo, David;Delgado-Hernandez, David Joaquin;Arteaga-Arcos, Juan Carlos;Flores-Gomora, Jhonnatan
    • Earthquakes and Structures
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    • v.12 no.3
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    • pp.349-357
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    • 2017
  • The design of reinforced concrete structures strongly depends on the value of the compression concrete strength used for the structural components. Given the uncertainties involved on the materials quality provided by concrete manufacturers, in the construction stage, these components may be either over or under-reinforced respect to the nominal condition. If the structure is under reinforced, and the deficit on safety level is not as large to require the structure demolition, someone should assume the consequences, and pay for the under standard condition by means of a penalty. If the structure is over reinforced, and other failure modes are not induced, the builder may receive a bonus, as a consequence of the higher, although unrequested, building resistance. The change on the building safety level is even more critical when the structure is under a seismic environment. In this research, a reliability-based criteria, including the consideration of expected losses, is proposed for bonification/penalization, when there are moderated differences between the supplied and specified reinforced concrete strength for the buildings. The formulation is applied to two hypothetical, with regular structural type, 3 and 10 levels reinforced concrete buildings, located on the soft soil zone of Mexico City. They were designed under the current Mexican code regulations, and their responses for typical spectral pseudoaccelerations, combined with their respective occurrence probabilities, are used to calculate the building failure probability. The results are aimed at providing objective basis to start a negotiation towards a satisfactory agreement between the involved parts. The main contribution resides on the explicit consideration of potential losses, including the building and contents losses and the business interruption due to the reconstruction period.