A robust M-estimate adaptive equaliser for impulse noise suppression

In this paper, a FIR adaptive equaliser for impulse noise suppression is proposed. It is based on the minimization of an M-estimate objective function which has the ability to ignore or down-weight a large error signal when it exceeds certain thresholds. An advantage of the proposed method is that its solution is governed by a system of linear equations, called the M-estimate normal equation. Therefore, traditional fast algorithms like the recursive least squares algorithm can be applied. Using a robust estimation of the thresholds and the recursive least square algorithm, an M-estimate RLS (M-RLS) algorithm is developed. Simulation results show that the proposed algorithm has better convergence performance than the N-RLS and MN-LMS algorithms when the input signal of the equaliser is corrupted by individually or consecutive impulse noises. It also shares the low steady state error of the traditional RLS algorithm.published_or_final_versio

A family of spread-sequences for CDMA system in a multipath fading channel

A new class of orthogonal code-division multiple access (CDMA) system is developed. The key characteristic of the system is that the data symbols are spreaded by a spread-sequence that is longer than the period of the symbol and hence overlapped with the neighboring symbols. Using this approach, temporal diversity is incorporated with other diversities. Due to the temporal diversity, the proposed CDMA system performs well in a fading environment. In this paper, a method for designing such a spread-sequence using filter bank theory is presented. The length of the spread-sequence could be varied according to the requirement. Simulation results show that the proposed spread-sequence based system yields lower BER than the conventional Gold codes based DS/CDMA system.published_or_final_versio

Long non-coding RNA deregulation in tongue squamous cell carcinoma

Background. The deregulated tumorigenic long non-coding RNA (lncRNA) has been reported in several malignancies. However, there is still no comprehensive study on tongue squamous cell carcinoma (SCC). Methods. Functional reannotation for the human lncRNA was carried out by ncFANs. Real-time quantitative PCR was used to validate the identified lncRNAs. Results. Using the functional annotation algorithm from ncFANs, 8 differentially expressed lncRNAs were identified. Lnc-PPP2R4-5, lnc-SPRR2D-1, lnc-MAN1A2-1, lnc-FAM46A-1, lnc-MBL2-4:1, and lnc-MBL2-4:3 were upregulated in the microdissected tongue SCC tissues. In comparison, lnc-AL355149.1-1 and lnc-STXBP5-1 showed significant downregulation. High level of lnc-MBL2-4:3 was significantly associated with the node positive tongue SCC patients. Further, patients with advanced T-stage demonstrated a further reduction of lnc-AL355149.1-1 in the tumor tissues. Treatment of tongue SCC cells with 5-fluorouracil and paclitaxel can reserve the expression patterns observed in the tongue SCC tissues. Further, changes of lnc-MBL2-4:3 and lnc-AL355149.1-1 expression levels were noticed in the cisplatin-resistant tongue SCC cells. Conclusions. Our results demonstrated that functional reannotation allows us to identify novel lncRNAs using the existing gene expression array dataset. The association of lncRNA with the T-stage and nodal status of tongue SCC patients suggested that lncRNA deregulation was involved in the pathogenesis of tongue SCC.published_or_final_versio

Differential expression of long noncoding RNA in primary and recurrent nasopharyngeal carcinoma

Background. Recent studies suggested that non-protein-coding genes are implicated in the tumorigenic process of nasopharyngeal carcinoma (NPC). In the present study, we aimed to identify the differentially expressed long noncoding RNA (lncRNA) using data available in the public domain. Methods. Microarray data set GSE12452 was reannotated with ncFANs. Real-time quantitative PCR was used to quantify and validate the identified lncRNAs in NPC. Results. In primary NPC, upregulation of lnc-C22orf32-1, lnc-AL355149.1-1, and lnc-ZNF674-1 was observed. High levels of lnc-C22orf32-1 and lnc-AL355149.1-1 were significantly associated with the male patients. In addition, increased expression of lnc-C22orf32-1 and lnc-ZNF674-1 was associated with advanced tumor stages. Recurrent NPC displayed a distinctive lncRNA expression pattern. lnc-BCL2L11-3 was significantly increased in the recurrent NPC tissues. In addition, significant reduction of lnc-AL355149.1-1 and lnc-ZNF674-1 was observed in the recurrent NPC tissues. Conclusions. Our results demonstrated that it is feasible to identify the differentially expressed lncRNA in the microarray dataset by functional reannotation. The association of lncRNA with gender and tumor size implicated that lncRNA possibly plays a part in the pathogenesis of primary NPC. Further, the distinctive lncRNA identified in the recurrent NPC may reveal a distinctive development mechanism underlying tumor recurrence. © 2014 Wei Gao et al.published_or_final_versio

A perceptual based rate control scheme for MPEG-2

In this paper, a new perceptual based rate control algorithm for MPEG-2 is presented. The algorithm first determines the target bit count for each frame using simple statistical models. Precise bit allocation is used to adjust the macroblock quantization scale factors to meet the given bit count, with the uniform visual fidelity as the primary objective. Since the buffer is very stable, it is less sensitive to transmission delay, Experimental results showed that it gave better visual quality and less buffer variations as compared to the TM5 rate control scheme.published_or_final_versio

Buffer control algorithm for low bit-rate video compression

In this paper, a new buffer control algorithm for motion-compensated hybrid DPCM/DCT coding (like H.261 and MPEG-1 I pictures) is presented. The algorithm uses the bit allocation algorithm to determine the quantization scale factor of each macroblock under a given target bit rate. An important advantage of the algorithm is that it has precise control of the buffer and avoids buffer overflow events which is a severe problem in low bit rate video coder. Furthermore, the coder is able to allocate bits to the picture as a whole, resulting in better rate-distortion trade-off. Simulation results show that the H.261 coder, using the proposed algorithm, can achieve a higher PSNR and better visual quality than codec using conventional buffer control algorithm.published_or_final_versio

Least mean M -estimate algorithms for robust adaptive filtering in impulse noise

This paper proposes two gradient-based adaptive algorithms, called the least mean M-estimate and the transform domain least mean M -estimate (TLMM) algorithms, for robust adaptive filtering in impulse noise. A robust M -estimator is used as the objective function to suppress the adverse effects of impulse noise on the filter weights. They have a computational complexity of order O(N) and can be viewed, respectively, as the generalization of the least mean square and the transform-domain least mean square algorithms. A robust method for estimating the required thresholds in the M -estimator is also given. Simulation results show that the TLMM algorithm, in particular, is more robust and effective than other commonly used algorithms in suppressing the adverse effects of the impulses. © 2000 IEEE.published_or_final_versio

Generalized lapped transform (GLT) based high-speed for transmissionfor wireless mobile communications

In this paper, we describe a generalized lapped transform (GLT) based high-speed transmission technique for wireless mobile communications over Rayleigh fading channels. In this technique, the high-rate data bits are serial-to-parallel converted into low-rate data streams which are then modulated by the GLT based signature sequences. Numerical results show that the GLT based system gives better results than the Walsh code, PN concatenated sequence based system (Letaief et al., 1995)published_or_final_versio

Post-processing of transform coded images using selective filtering and fuzzy-based enhancement

Transform coding often leads to artifacts called blocking when the image or video is compressed to low bit-rate. In this paper, a new post-processing scheme using selective low-pass filtering and fuzzy-based enhancement is proposed. The merit of the scheme is that it can remove most of the blocking artifacts found in image or video coding while preserving most of the fine details. Simulation results demonstrated that the proposed algorithm can significantly improve the visual quality of the decoded image.published_or_final_versio

A multiresolution two-layer video codec for networking applications

We propose an improved multiresolution two-layer video codec that can operate at a base layer of 64 kbps and a variable bit rate second layer (VBR). The basic idea is to use a multiresolution technique to reduce the original CIF format video to the QCIF format. The low-resolution video is then encoded with an improved H.261 codec. To reduce the bit rate of the second layer, the residuals are encoded with the discrete cosine transform (DCT) using perceptually weighted quantization step sizes. Simulation results show that the Miss America sequence can be transmitted at 64 kbps in the CIF format with a reasonably good picture quality. For a good picture quality, the second layer would typically require 190 kbps.published_or_final_versio