A scheme of error correction for JPEG2000 codestream is proposed in this paper. The scheme uses a forward error correction code (FEC) and a data hiding technique. The headers and the higher quality layers of the codestream are coded using FEC codes. Then the parity data are separated from the FEC-coded data and hidden in the JPEG2000 codestream. The hidden data are used for error correction at the decoder. Several error correction codes with different strength are selected for the main header, the tile-part headers, the packet headers, and the bodies. The codestream generated by the proposed scheme has backward compatibility with a standard JPEG2000 codestream. Thus, it can be decoded with a general decoder. Simulation results demonstrated the effectiveness of the proposed scheme.

FEC (Forward Error Correction) can repair the damage to communication quality due to packet loss. The growing requirement of FEC for high-quality video transmission is inevitable on broadband networks. We have designed and implemented FEC, and integrated it to our developed video transmission system named "mpeg2ts." Our goal is to make it possible to deploy this system on the broadband Internet. However, the problem with constant redundancy of FEC is that weakness to fluctuation of network condition. To resolve this problem, in this paper, we propose and evaluate an efficient FEC method for high-quality video transmission. The proposed mechanisms can provide robustness as well as saving of processing load and optimization of bandwidth consumption. Moreover, we integrate it into a system to deploy it on the real broadband Internet. Transmission experiment demonstrates availability of developed system deployed on the network.

To increase the spectral utilization efficiency of a wireless link, multiple-input multiple-output (MIMO) systems can be employed to transmit several data streams in parallel at the same time and on the same frequency but from different transmit antennas. However, at the receiver side multi-stream detection is needed. In this paper, ordered successive MMSE detection (OSD) is considered as a low-complexity detection scheme. OSD's main computational cost lies in computing the nulling weights that correspond to each stage of successive detection. In this paper, we develop an efficient semi-adaptive approach to generate MMSE weights. This semi-adaptive approach efficiently combines two approaches: channel estimates-based direct matrix inversion weights generation (direct approach) and Recursive Least Squares (RLS) algorithm-based weights generation (adaptive approach). Although the direct approach alone performs better than the adaptive approach, it is more complex for updating weights within the tracking mode. On the other hand, the adaptive approach alone is less complex in updating weights within the tracking mode, but converges slowly within the training mode. Our combined semi-adaptive approach effectively offsets these disadvantages. We demonstrate, through computer simulations, that the semi-adaptive approach can achieve the BER of the direct approach in slow time-varying MIMO channels, while its computational complexity is less than or comparable to that of the adaptive approach.

We propose using SQP (Sequential Quadratic Programming) to directly recover 3D quadratic surface parameters from multiple views. A surface equation is used as a constraint. In addition to the sum of squared reprojection errors defined in the traditional bundle adjustment, a Lagrangian term is added to force recovered points to satisfy the constraint. The minimization is realized by SQP. Our algorithm has three advantages. First, given corresponding features in multiple views, the SQP implementation can directly recover the quadratic surface parameters optimally instead of a collection of isolated 3D points coordinates. Second, the specified constraints are strictly satisfied and the camera parameters and 3D coordinates of points can be determined more accurately than that by unconstrained methods. Third, the recovered quadratic surface model can be represented by a much smaller number of parameters instead of point clouds and triangular patches. Experiments with both synthetic and real images show the power of this approach.

In this paper, using the exact expression for the pairwise error probability derived in terms of the message symbol distance between two message vectors rather than the codeword symbol distance between two transmitted codeword matrices, the exact closed form expressions for the symbol error probability of any linear orthogonal space-time block codes in slow Rayleigh fading channel are derived for QPSK, 16-QAM, 64-QAM, and 2 56-QAM.

In this letter, we address the performance evaluation of a space-time block coded (STBC) orthogonal frequency and code division multiplexing (OFCDM) system encountered with time-variant channels. For the performance evaluation, the average bit error rate (BER) impairment due to imperfect channel information is investigated taking into account the effect of time-varying channels. Derived results show that the loss of orthogonality due to the time variation of the channel incurs the channel estimation error, which causes performance degradation.

This paper describes feasibility of a proposed fixed wireless access system with CDMA technology. The system adopts a primary modulation of 16 QAM and the same frequency allocation in all cells to improve spectral efficiency. The system capacity is 1 Gbps per cell within 120 MHz bandwidth. The number of available orthogonal codes corresponds to the orthogonal code length in the system. All subscribers can attain an error free condition with output power control in the presence of inter-cell interference. The following two items are considered to examine the proposed system feasibility. 1) A test modem is fabricated, and a back-to-back modem BER performance is measured. An inter-symbol interference (ISI) level of the modem is estimated with the measured performance. 2) A computer simulation of down-link power control is carried out considering inter-cell interference and impairment factors of the power control such as intra-sector interference caused by the ISI and limited ranges of total and relative output power controls. The simulation results show that the proposed system would be feasible because the obtained power penalties caused by the above impairment factors are negligible.

The application of fault injection in the context of dependability benchmarking is far from being straightforward. One decisive issue to be addressed is to what extent injected faults are representative of the considered faults. This paper proposes an approach to analyze the effects of real and injected faults.

Computers are increasingly used for implementing control algorithms in safety-critical embedded applications, such as engine control, braking control and flight surface control. Consequently, computer errors can have severe impact on the safety of such systems. Addressing the coupling of control performance with computer related errors, this paper develops a methodology for analyzing the impacts data errors have on control system dependability. The impact of a data error is measured as the resulting control error. We use maximum bounds on this measure as the criterion for control system failure (i.e., if the control error exceeds a certain threshold, the system has failed). In this paper we a) develop suitable models of computer faults for analysis of control level effects and related analysis methods, and b) apply traditional control theory analysis methods for understanding the impacts of data errors on system dependability. An automobile slip-control brake-system is used as an example showing the viability of our approach.

In an LSI design process, Engineering Change Orders (ECO's) are often given even after the layout process. This letter presents an approach to change the design to satisfy the new specification with ECO's by employing an error diagnosis technique. Our approach performs incremental synthesis using spare cells embedded on the original layout. Experimental results show that applying the error diagnosis technique to incremental synthesis is effective to suppress increase in delay time caused by ECO's.

Data compression is popularly applied to computer systems and communication systems. Especially, lossless compression is applied to text compression. Since compressed data are very sensitive to errors, several error control methods for data compression using probability model, such as for arithmetic coding, have been proposed. This paper proposes to apply an unequal error protection, or a UEP, scheme to LZ77 coding and LZW coding. This investigates a structure of the compressed data and clarifies a part which is more sensitive to errors than the other by using theoretical analysis and computer simulation. The UEP scheme protects the error-sensitive part from errors more strongly than the others. Computer simulation says that the proposed scheme can recover from errors in the compressed data more effectively than the conventional methods.

Digital Subtraction Angiography (DSA) is a technique used for enhancement of small details in angiogram imaging systems. In this approach, X-ray images of a subject, after injection, are subtracted from a reference X-ray image, taken from the same subject before injection. Due to the exponential absorption property of X-rays, effects of small details at different depth appear differently on X-ray images. Consequently, image subtraction cannot be employed on the original images without any adjustment or modification. Proper modification, in this case, is to use some form of logarithmic operation on images before subtraction. In medical imaging systems, the system designer has a choice to implement this logarithmic operation in the analog domain, before digitization of the video signal, or in the digital domain after analog-to-digital conversion (ADC) of the original video signal. In this paper, the difference between these two approaches is studied and upper bounds for quantization error in both cases are calculated. Based on this study, the best approach for utilization of the logarithmic function is proposed. The overall effects of these two approaches on the inherent signal noise are also addressed.

In an optical time domain reflectometer type strain measurement system, we theoretically derive the shape of the Brillouin gain spectrum produced in an optical fiber under a parabolic strain distribution which is formed in a uniformly loaded beam. Based on the derived result, we investigate the effects of the parabolic strain distribution parameters and the measurement conditions such as the launched pulse width and the measurement position on the beam on the deformation of the Brillouin backscattered-light power spectrum shape. In addition, we investigate the strain measurement error resulting from the deformation of the power spectrum shape by analyzing the peak-power frequency at which the power spectrum is maximized.

Bit error rate estimation of the LEO satellite channel is presented. Since it could hardly be expressed the bit error rate under the practical degradation factors in a closed form, the method to predict the bit error rate using the known moments of the degradation factors is employed. The numerical example in this analysis is provided, especially, under the effects of Traveling Wave Tube Amplifier (TWTA) nonlinearity, fading effect and intersymbol interference (ISI). Under Ricean fading channel model, in the LEO environment, the result shows the system performance is worse and couldn't be used for voice communication when the LEO satellite is located at a lower elevation angle (EL). Besides, the degradation of the effect of ISI is more prominent when the LEO satellite is located at a higher EL.

Due to the explosive growth of the network technologies, 3D models and animations have led to a great interest in various media. Especially 3D mesh models (3D meshes), which approximate surfaces by polygonal meshes are widely used to model 3D objects. In 1D and 2D signals such as speech, audio, images, video, etc., the signal values are located on "grids", for example the signals of images are defined on pixels. Thus, the errors of such signals can be explicitly defined by differences of the values on the "grids". However since in the 3D meshes, vertices are located on arbitrary positions in a 3D space and are triangulated in arbitrary ways, the grids cannot be defined. This makes it difficult to measure error on the 3D meshes. In this paper, we propose a new numerical method to measure the errors between two different 3D meshes.

Power control error is well known for its negative effects on CDMA system capacity. In this Letter, an analytical model is developed to estimate the uplink capacity for a SIR-based power controlled CDMA cellular system. The voice capacity reduction due to power control error is numerically examined with this model.

MC-CDMA has attracted significant attention as a downlink communication method for fourth generation mobile communication systems. However, MC-CDMA has a peak power problem, similarly to other nonspread multicarrier systems. In this paper, we propose a novel peak power reduction technique for MC-CDMA using code selection at the transmitter. In the proposed system, the transmitter selects the code shift pattern from plural pre-assigned code shift patterns in each cluster to minimize the output peak power of downlink signals. The proposed technique can achieve the blind code detection of transmitting codes at the receiver. However, the detection performance degrades if the number of users is extremely large or extremely small. Therefore, in this paper, a code detection error recovery technique is also considered.

Probabilistic encryption becomes more and more important since its ability to against chosen-ciphertext attack. Applications like online voting schemes and one-show credentials are based on probabilistic encryption. Research on good probabilistic encryptions are on going, while many good deterministic encryption schemes are already well implemented and available in many systems. To convert any deterministic encryption scheme into a probabilistic encryption scheme, a randomized media is needed to apply on the message and carry the message over as an randomized input. In this paper, nonlinear codes obtained by certain mapping from linear error-correcting codes are considered to serve as such carrying media. Binary nonlinear codes obtained by Gray mapping from 4-linear codes are discussed as example for a such scheme.

The bit error rate (BER) for an uplink multicell multicarrier code-division multiple-access (MC-CDMA) system in Nakagami-m fading channels is derived and expressed in the form of a single integral. The result is obtained without the approximation for the ratio of the interference power from other-cell to the power from the user-of-interest. Numerical results demonstrate the impacts of other-cell interference and power control errors on the BER.

We present the channel capacity, specifically the mutual information, of an additive white Gaussian noise (AWGN) channel in the presence of phase noise, and investigate the effect of phase noise impairment on powerful error-correcting codes (ECCs) that normally operate in low signal-to-noise ratio (SNR) regions. This channel-induced impairment is common in digital coherent transmission systems and is caused by imperfect carrier tracking of the phase error detector for coherent demodulation. It is shown through semi-analytical derivation that decreasing the information rate from its ideal capacity to an information rate lower than its inherent capacity significantly mitigates the impairment caused by phase noise, and that operating systems in the low SNR region also lessen the phase noise impairment by transforming typical phase noise behavior into Gaussian-like behavior. We also demonstrate by computer simulation using turbo-trellis coded modulation (TTCM) with high-order quadrature amplitude modulation (QAM) signals that the use of capacity-approaching codes (CACs) makes transmission systems invulnerable to phase noise. To verify the effect of CACs on phase noise, simulation results of TTCM are also compared to that of trellis-coded modulation (TCM), which is used as an example of a conventional ECC operating at a relatively high SNR.