The text at hand presents an improved metric calculation for an Iterative Channel data Estimation (ICdE) technique in M-ary datatransmission over time-variant frequency selective channels. For low velocities, the pro...
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ISBN:
(纸本)9783800729470
The text at hand presents an improved metric calculation for an Iterative Channel data Estimation (ICdE) technique in M-ary datatransmission over time-variant frequency selective channels. For low velocities, the proposed technique can work with an initial channel estimate as datadetector only. In this case, the detector works similar to the Malgorithm, but with improved metric. In both cases, the advantage is that the metric averages over future symbols and thus yields results similar to detectors shortening the channel by using an allpass prefilter to obtain a minimum phase Composite Channel Impulse Response (CCIR), thus, compacting the energy of the CCIR to a few taps, and then using a reduced complexity sequence detector such as delayeddecision Feedback Sequence Estimator (ddFSE), optionally with Reduced State Sequence Estimation (RSSE) or Adaptive State Allocation (ASA). ICdE needs no Front-End Prefilter (FEP) and has advantages in fast time-variant frequency selective channels, where a FEP, which is only block-adapted to the channel, looses some of its energy compaction capabilities with increasing velocity. These channels are typical for high speed train and automotive connections. As a concurrent receiver design, ddFSE is utilized, optionally with Per-Survivor processing (PSP), to mitigate the effects of the time-varying channel, but cannot compensate the loss due to the block adapted FEP. We use the GSM/EdGE modulation format here, in order enable other researchers to compare their results.
This paper presents a new approach for interactive 3d (volume) mesh manipulations based on 'on-the-fly' quality measures in order to keep the consistency of the mesh. Within pure engineering tasks, such as the...
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This paper presents a new approach for interactive 3d (volume) mesh manipulations based on 'on-the-fly' quality measures in order to keep the consistency of the mesh. Within pure engineering tasks, such as the analysis of physical behaviour, virtual environments only established as post processing unit, in which simulation results can be interactively displayed and visualized to get more in depth information about the simulation mock up. However, most of the simulations are done off-line which do not allow for interactive `what-if' analysis in view of a change of the primary design domain. As design changes of the underlying CAx/FE models usually imply many manual interferences, repair and efforts (re-meshing tasks, grid repair, etc.) in order to guarantee elements of high quality during re-meshing or mesh refinement tasks, an evaluation within virtual environments is not suitable with current techniques. Thus this paper aims at introducing our approach in order to change 3d volumetric meshes on the fly and keep the consistency of the newly generated mesh in view of engineering analysis
dendritic spines play an important role in synaptic transmission. Spines are small protrusions formed on the shafts of dendrites and they are manifest of many neurological conditions. Three dimensional images of dendr...
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ISBN:
(纸本)078039576x
dendritic spines play an important role in synaptic transmission. Spines are small protrusions formed on the shafts of dendrites and they are manifest of many neurological conditions. Three dimensional images of dendrites and spines are obtained by confocal and two-photon laser scanning microscopy. We present an image processing method based on shape analysis to detect spines and separate spines from the dendrites for quantitative study. The method applies two grassfire procedures to first find the tips of spines and then reversely locate the boundary between spines anddendrites. The boundary is determined as the propagation front that undergoes the maximum change in plane area of the grassfire procedure. We use real data to demonstrate the performance of the method
The Heart Institute (InCor) of Sao Paulo has been committed to the goal of integrating all clinical information within the institution. In the last few years, InCor has successfully created a system for transmission, ...
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The Heart Institute (InCor) of Sao Paulo has been committed to the goal of integrating all clinical information within the institution. In the last few years, InCor has successfully created a system for transmission, archiving, retrieval, processing andvisualization of Medical Images and also a Hospital Information System that stores the administrative and clinical information. These integrated subsystems form InCor's Electronic Patient Record (EPR). This work describes the experience in the effort to develop a functional and comprehensive EPR, which includes access control, lab exams, images (static, dynamic and3d), clinical reports, documents and even real-time vital signals. Currently, more than 13TB of dICOM images have been stored using the proposed architecture. The EPR stores more than 5 GB/day of integrateddata and presents more than 1400 hits per day. The proposed storage subsystem allows six months of visibility for rapid retrieval and more than two years for automatic retrieval using a jukebox.
The selection of appropriate multiple access technology is the main issue in design anddevelopment of beyond3G (B3G) wireless systems. This article considers orthogonal frequency-division multiplexing (OFdM) scheme ...
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The selection of appropriate multiple access technology is the main issue in design anddevelopment of beyond3G (B3G) wireless systems. This article considers orthogonal frequency-division multiplexing (OFdM) scheme as a key technique to implement in next-generation mobile systems. The introduction of OFdM multicarrier technique in new hybrid multiple access technologies should provide a solution for problems limiting current mobile systems, such as sensitivity to multipath conditions, poor bandwidth efficiency, interference and capacity issues, high signal processing complexity and inadequate performance of high-speeddatatransmission. The theoretical background, characteristics and practical applications of some of the most important multiple access combinations will be reviewed. Finally, the implementation of OFdM in existing single carrier 3G systems and coexistence will be shortly addressed in conclusion
Hardware platforms and testbeds are an essential tool to evaluate, in realistic scenarios, the performance of multiple-input-multiple-ouput (MIMO) systems. In this work we present a simple and easily reconfigurable 2 ...
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Hardware platforms and testbeds are an essential tool to evaluate, in realistic scenarios, the performance of multiple-input-multiple-ouput (MIMO) systems. In this work we present a simple and easily reconfigurable 2 times 2 MIMO testbed for the rapid prototyping of the signal processing baseband functions. The signal generation module consists of a host PC equipped with a board that contains two high performance 100 MHz dACs and a 1 GB memory module that allows the transmission of extremely large frames of data. At the receiver side, we use another host PC equipped with two 105 MHz AdCs, another 1 GB memory module and a trigger that starts the acquisition process when the presence of signal is detected. The platform has been designed to operate at the ISM band of 2.4 GHz with a RF bandwidth of 20 MHz. In order to minimize the number of dAC and AdC circuits, signals are generated and acquired at an IF of 15 MHz. Upconversion to RF is performed with two RF vectorial signal generators (Agilent E4438C) anddownconversion with two specific circuits designed from commercial components. Transmitter and receiver signal processing functions are implemented off-line in Matlab. To illustrate the performance and capabilities of the platform, we present the results of two experiments of a 2 times 2 MIMO transmission with Alamouti coding.
The text at hand presents an improved metric calculation for an Iterative Channel data Estimation (ICdE) technique in M-ary datatransmission over time-variant frequency selective channels. For low velocities, the pro...
详细信息
The text at hand presents an improved metric calculation for an Iterative Channel data Estimation (ICdE) technique in M-ary datatransmission over time-variant frequency selective channels. For low velocities, the proposed technique can work with an initial channel estimate as datadetector only. In this case, the detector works similar to the M-algorithm, but with improved metric. In both cases, the advantage is that the metric averages over future symbols and thus yields results similar to detectors shortening the channel by using an allpass prefilter to obtain a minimum phase Composite Channel Impulse Response (CCIR), thus, compacting the energy of the CCIR to a few taps, and then using a reduced complexity sequence detector such as delayeddecision Feedback Sequence Estimator (ddFSE), optionally with Reduced State Sequence Estimation (RSSE) or Adaptive State Allocation (ASA). ICdE needs no Front-End Prefilter (FEP) and has advantages in fast time-variant frequency selective channels, where a FEP, which is only block-adapted to the channel, looses some of its energy compaction capabilities with increasing velocity. These channels are typical for high speed train and automotive connections. As a concurrent receiver design, ddFSE is utilized, optionally with Per-Survivor processing (PSP), to mitigate the effects of the time-varying channel, but cannot compensate the loss due to the block adapted FEP. We use the GSM/EdGE modulation format here, in order enable other researchers to compare their results.
In this paper, a method of generating a three-dimensional (3-d) geometric model for large-scale natural environments with trees is presented. The environment mapping method, which uses range images as measurement data...
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In this paper, a method of generating a three-dimensional (3-d) geometric model for large-scale natural environments with trees is presented. The environment mapping method, which uses range images as measurement data, consists of three main phases. First, geometric feature objects are extracted from each of the range images. Second, the relative coordinate transformations (i.e., registrations) between the sensor viewpoint locations, where the range data are measured, are computed. Third, an integrated map is formed by transforming the submap data into a common frame of reference. Tree trunks visible in the range images are modeled with cylinder segments and utilized as reference features for registration computation. The final integrated3-d model consists of the cylinder segments representing the visible sections of the tree trunks, as well as of the ground elevation data. The constructed environment map can be utilized as, for example, a virtual task environment for outdoor robotic machines such as new-generation forest working machines or service robots.
It is an important topic to apply VR to geo-datavisualization. This paper discusses the concepts of spatial phenomenon, spatial entity and spatial object related to geo-data. The hierarchical representation is applie...
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