Transmission Distortion Research Articles

Stereo Video Transmission Distortion Derived Algorithm Based On Data Partitioning In H.264/AVC

H.264/AVC coding standard slices the encoded Data using the Data Partitioning (DP) based on syntax priority to improve the error resistance for H.264 bit stream. According to this feature, considering the temporal and spatial correlation in stereoscopic video, network performance and terminal error concealment technology. A derived algorithm for determining the transmission distortion based on different DP parts in a Group-ofPictures (GoP) is proposed. The algorithm takes both the distortion introduced by error diffusion and error concealment into account, which can be estimated by the stereo video quality at encode side under the condition of the specific network. Experimental results show that the algorithm used to calculate the distortion basically coincided with simulation results, and the algorithm can be applied to different sequences with various movement characteristics.

MTHFR c.677C>T is a risk factor for non-syndromic cleft lip with or without cleft palate in Chile.

The functional variant within the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene c.677C>T, producing alterations in folate metabolism, has been associated with the risk of non-syndromic cleft lip with or without cleft palate (NSCL/P). We assessed this association in a Chilean population using a combined analysis of case-control and case-parent trio samples. Samples of 165 cases and 291 controls and 121 case-parent trios (sharing the cases) were genotyped. Odds ratio (OR) was estimated for case-control (allele and genotype frequency differences), and this result was confirmed by allele transmission distortion in trios. Due to that these samples are not independent, a combined OR was also computed. Maternal genotype effect was additionally evaluated based on a log-linear method. Borderline but not significant OR (1.28; CI 0.97-1.69) was observed for risk allele (T) in the case-control sample. However, triad sample showed a significant association (OR 1.56: CI 1.09-2.25) which was confirmed by the combined OR (1.37; CI 1.11-1.71). Maternal genotype has been also associated with the phenotype (P=0.002). In contrast to previous reports considering Chilean subjects, our results demonstrated that the offspring and maternal genotypes for MTHFR c.677C>T variant are strongly associated with NSCL/P in this Chilean population.

Outage capacity and source distortion analysis for NOMA users in 5G systems

This Letter analyses the impact of the outage probability on the outage capacity and the expected source distortion of information transmission to non-orthogonal multiple access (NOMA) users with a fixed set of power allocation coefficients. The analysis shows that the outage probability at which a strong user experiences the maximum outage capacity (and the minimum expected distortion) is characteristically different from that of a weak user. Moreover, the outage probability that maximises the outage capacity does not provide the minimum source distortion for both users. The analysis is validated against simulation.

No evidence for female discrimination against male house mice carrying a selfish genetic element.

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous (+/t) mice leads to high embryo mortality. Previous experiments showing that +/t females avoid this incompatibility cost by preferring +/+ versus +/t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against +/t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between gametes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by +/t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms.

Evaluating and Reducing the Envelope Fluctuations of OFDM Signals Based on Distortion Prediction

Abstract Orthogonal frequency division multiplexing (OFDM) signals with large envelope fluctuations are prone to be affected by power amplifier (PA), resulting in degradation of system performance. Peak-to-average power ratio (PAPR) and cubic metric (CM) are commonly used as the reduction criteria of envelope fluctuations of OFDM signals. However, our analysis shows that minimizing the PAPR or CM does not necessarily mean the optimization of system performance, since both metrics are inadequate to quantify the distortion in nonlinear OFDM transmission. In this paper, we fully discuss the effects of PA nonlinearity on OFDM signals and propose a new metric called distortion component metric (DCM), which is closely related to the nonlinear distortion caused by the PA. We compare the system performance when several metrics are respectively used as the reduction criterion for the selective mapping scheme. It is shown that in the presence of memoryless or memory PA, the usage of DCM can provide better inband and out-of-band performance than PAPR and CM.

Content-Aware Concurrent Multipath Transfer for High-Definition Video Streaming over Heterogeneous Wireless Networks

Delivering high-definition (HD) wireless video under stringent delay constraint is challenging with regard to the limited network resources and high transmission rate. Concurrent multipath transfer (CMT) using stream control transmission protocol (SCTP) exploits the multihoming feature of mobile devices to establish associations with different access networks. In this paper, we study the multihomed HD video communication with SCTP over heterogeneous wireless networks. The existing CMT schemes mainly treat the traffic data in a content-agnostic fashion, and thus cannot effectively leverage the scarce wireless resources to maximize the perceived video quality. To address this critical issue, we propose a content-aware CMT (CMT-CA) solution that featured by the unequal frame-level scheduling based on estimated video parameters and feedback channel status. First, we develop an analytical framework to model the total distortion of parallel video transmission over multiple wireless access networks. Second, we introduce a joint congestion control and data distribution scheme to minimize the total distortion based on online quality evaluation and Markov decision process (MDP). The performance of CMT-CA is evaluated through extensive semi-physical emulations in Exata involving HD video encoded with H.264 codec. Experimental results show that CMT-CA outperforms the reference schemes in terms of video peak signal-to-noise ratio (PSNR), end-to-end delay, and goodput. Or conversely, CMT-CA achieves the same video quality with $20$ percent bandwidth conservation.

Analysis of highway reflection noise reduction using transparent noise barrier types

Transparent type noise barrier is a desirable facility since it provides a secure view to drivers and passengers. However, reflection from this type of barrier could annoy dwellers on the sides of the road. To reduce reflection noise by transparent type barrier, modification can be made to the shapes on the front side and hence get effects by distortion of sound transmission. To achieve this, we have conducted simulation by which the effects of patterned screens of noise barrier on high-ways were investigated. The reduction effects of reflected sounds were evaluated for swelling, swelling with curved, rectangular and V-shaped screen type barriers, compared to the planar panel. The emitting noise was generated by 6-lane road and the patterned noise barriers had shown the reduction effects, especially in swelling and swelling with curved type for middle height dwellers, and the V-shaped screen type for higher elevation dweller. The swelling-type showed a decrease of 0.7~1.2 dB, performing the best diminution effect among the tested noise barriers.

Asymmetry of parental origin in long QT syndrome: preferential maternal transmission of KCNQ1 variants linked to channel dysfunction.

Transmission distortion of disease-causing alleles in long QT syndrome (LQTS) has been reported, suggesting a potential role of KCNQ1 and KCNH2 in reproduction. This study sought to investigate parental transmission in LQTS families according to ethnicity, gene loci (LQT1-3: KCNQ1, KCNH2, and SCN5A) or severity of channel dysfunction. We studied 3782 genotyped members from 679 European and Japanese LQTS families (2748 carriers). We determined grandparental and parental origins of variant alleles in 1903 children and 624 grandchildren, and the grandparental origin of normal alleles in healthy children from 44 three-generation control families. LQTS alleles were more of maternal than paternal origin (61 vs 39%, P<0.001). The ratio of maternally transmitted alleles in LQT1 (66%) was higher than in LQT2 (56%, P<0.001) and LQT3 (57%, P=0.03). Unlike the Mendelian distribution of grandparental alleles seen in control families, variant grandparental LQT1 and LQT2 alleles in grandchildren showed an excess of maternally transmitted grandmother alleles. For LQT1, maternal transmission differs according to the variant level of dysfunction with 68% of maternal transmission for dominant negative or unknown functional consequence variants vs 58% for non-dominant negative and variants leading to haploinsufficiency, P<0.01; however, for LQT2 or LQT3 this association was not significant. An excess of disease-causing alleles of maternal origin, most pronounced in LQT1, was consistently found across ethnic groups. This observation does not seem to be linked to an imbalance in transmission of the LQTS subtype-specific grandparental allele, but to the potential degree of potassium channel dysfunction.

No-Reference Transmission Distortion Modelling for H.264/AVC-Coded Video

In this paper, a low-complexity No-reference algorithm for real-time estimation of the channel induced distortion is proposed. The algorithm is capable of providing video quality evaluation for the network service provider perspective to the end-user. An analytical model has been proposed to estimate the mean square error (mse) distortion at the MB, frame, and sequence level. The algorithm takes into account the spatiotemporal dynamics of the video sequence. The transmission distortion is estimated because of the spatial and temporal error concealment, along with the effects of temporal propagation distortion due to the motion compensation. The algorithm is capable of measuring the transmission distortion for video sequence encoded as I, P, and B frames, as compared to most of the proposed algorithms which are not capable of working with B frames at all. However, the bandwidth-constrained resource networks make compression very important, which is not possible without B frames. The proposed algorithm is experimentally tested and validated with video signals encoded according to the H.264/AVC video coding standard. A novel experimental setup is established to simulate the video traffic and simulation results show that the proposed algorithm shows better results as compared to other proposed algorithms.

Utility-Based Optimized Cross-Layer Scheme for Real-Time Video Transmission Over HSDPA

In this paper we first build an accurate and general transmission distortion model for H.264/AVC video streams to estimate the importance of each packet. Then, a utility-based optimized cross-layer resource allocation, MCS selection, and packet scheduling algorithm for real-time video transmission over HSDPA is studied. The utility here refers to the packet utility which is defined as a function of the packet urgency and the packet importance . Transmitting the packets with greater utility values firstly in each TTI can provide a higher level of video quality for the users. Thus, we formulate an optimization problem with the objective of maximizing the aggregate packet utility over all the users under the HSDPA physical resource constraints . In order to obtain an optimal transmission strategy, a dynamic programming -based cross-layer algorithm (DPCLA) is proposed. In view of its high complexity, we further develop a greedy-based cross-layer algorithm (GCLA) to find a suboptimal solution. Simulation results show that the proposed utility-based optimized cross-layer scheme, including the proposed transmission distortion model and the algorithms of DPCLA and GCLA, can provide higher received video quality than the existing ones for video transmission over HSDPA.

EVOLUTION. Fruit flies diversify their offspring in response to parasite infection.

The evolution of sexual reproduction is often explained by Red Queen dynamics: Organisms must continually evolve to maintain fitness relative to interacting organisms, such as parasites. Recombination accompanies sexual reproduction and helps diversify an organism's offspring, so that parasites cannot exploit static host genotypes. Here we show that Drosophila melanogaster plastically increases the production of recombinant offspring after infection. The response is consistent across genetic backgrounds, developmental stages, and parasite types but is not induced after sterile wounding. Furthermore, the response appears to be driven by transmission distortion rather than increased recombination. Our study extends the Red Queen model to include the increased production of recombinant offspring and uncovers a remarkable ability of hosts to actively distort their recombination fraction in rapid response to environmental cues.

A prezygotic transmission distorter acting equally in female and male zebra finches Taeniopygia guttata.

The two parental alleles at a specific locus are usually inherited with equal probability to the offspring. However, at least three processes can lead to an apparent departure from fair segregation: early viability selection, biased gene conversion and various kinds of segregation distortion. Here, we conduct a genome-wide scan for transmission distortion in a captive population of zebra finches (Taeniopygia guttata) using 1302 single-nucleotide polymorphisms (SNPs) followed by confirmatory analyses on independent samples from the same population. In the initial genome-wide scan, we found significant distortion at three linked loci on chromosome Tgu2 and we were able to replicate this finding in each of two follow-up data sets [overall transmission ratio=0.567 (95% CI=0.536-0.600), based on 1101 informative meioses]. Although the driving allele was preferentially transmitted by both heterozygous females [ratio=0.560 (95% CI=0.519-0.603)] and heterozygous males [ratio=0.575 (95% CI=0.531-0.623)], we could rule out postzygotic viability selection and biased gene conversion as possible mechanisms. Early postzygotic viability selection is unlikely, because it would result in eggs with no visible embryo and hence no opportunity for genotyping, and we confirmed that both females and males heterozygous for the driving allele did not produce a larger proportion of such eggs than homozygous birds. Biased gene conversion is expected to be rather localized, while we could trace transmission distortion in haplotypes of several megabases in a recombination desert. Thus, we here report the rare case of a prezygotically active transmission distorter operating equally effectively in female and male meioses.

Hybridization in closely related Rhododendron species: half of all species-differentiating markers experience serious transmission ratio distortion.

An increasing number of studies of hybridization in recent years have revealed that complete reproductive isolation between species is frequently not finalized in more or less closely related organisms. Most of these species do, however, seem to retain their phenotypical characteristics despite the implication of gene flow, highlighting the remaining gap in our knowledge of how much of an organism’s genome is permeable to gene flow, and which factors promote or prevent hybridization. We used AFLP markers to investigate the genetic composition of three populations involving two interfertile Rhododendron species: two sympatric populations, of which only one contained hybrids, and a further hybrid-dominated population. No fixed differences between the species were found, and only 5.8% of the markers showed some degree of species differentiation. Additionally, 45.5% of highly species-differentiating markers experienced significant transmission distortion in the hybrids, which was most pronounced in F1 hybrids, suggesting that factors conveying incompatibilities are still segregating within the species. Furthermore, the two hybrid populations showed stark contrasting composition of hybrids; one was an asymmetrically backcrossing hybrid swarm, while in the other, backcrosses were absent, thus preventing gene flow.

Channel estimation in OFDM systems using neural network technology combined with a genetic algorithm

Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation used in a variety of broadband systems, such as asymmetric digital subscriber lines, very-high-speed digital subscriber lines, digital video and audio broadcasting, and wide local area network standards. OFDM is a promising solution achieving high data rates in a mobile environment. In wireless communication systems, signal distortion and attenuation in transmission caused by multipath effects makes it necessary to obtain knowledge related to the channel impulse response using channel estimation to provide compensation. This study combined a back propagation neural network for the estimation of channel and compensation signals with a genetic algorithm to improve performance and the convergence rate. We compared bit error rates and the mean square error of the proposed neural network with that of the conventional neural network, the least square (LS) algorithm, and the minimum mean square error (MMSE) algorithm in existing OFDM channel environments. Our results demonstrate that the proposed algorithm outperforms the LS algorithm and is on par with the MMSE algorithm.

Analysis of Nonlinear Distortion and SSII Cancellation in EAM-Based IMDD OFDM Transmission

In terms of second-order nonlinearity, nonlinear distortion in an EAM-based IMDD OFDM system is deterministically modeled as subcarrier-to-subcarrier intermixing interference (SSII), such that DSP-based nonlinear compensation can be provided by decision-aided SSII cancellation at the receiver. The effectiveness of SSII cancellation heavily relies on the accuracy of SSII calculation, which is determined mainly by the modulation model adopted. This study made comprehensive comparisons of three small-signal models (constant-chirp, dynamic-chirp, and nonlinear-E/O models). We then combined theory and experiment results to examine the characteristics of SSII estimation and cancellation using various models, such as SSII spectra, regression coefficients, and correlation coefficients between the SSII and the total received errors, as well as the relationship between improvements in performance and the correlation coefficient. The nonlinear-E/O model is the most comprehensive, and as a result presents the flattest regression coefficient and highest correlation coefficient, which results in the most pronounced improvement in performance.

Learning about the X from our parents.

The X chromosome is generally understudied in association studies, in part because the analyst has had limited methodological options. For nuclear-family-based association studies, most current methods extend the transmission disequilibrium test (TDT) to the X chromosome. We present a new method to study association in case-parent triads: the parent-informed likelihood ratio test for the X chromosome (PIX-LRT). Our method enables estimation of relative risks and takes advantage of parental genotype information and the sex of the affected offspring to increase statistical power to detect an effect. Under a parental exchangeability assumption for the X, if case-parent triads are complete, the parents of affected offspring provide an independent replication sample for estimates based on transmission distortion to their affected offspring. For each offspring sex we combine the parent-level and the offspring-level information to form a likelihood ratio test statistic; we then combine the two to form a combined test statistic. Our method can estimate relative risks under different modes of inheritance or a more general co-dominant model. In triads with missing parental genotypes, the method accounts for missingness with the Expectation-Maximization algorithm. We calculate non-centrality parameters to assess the power gain and robustness of our method compared to alternative methods. We apply PIX-LRT to publically available data from an international consortium of genotyped families affected by the birth defect oral cleft and find a strong, internally-replicated signal for a SNP marker related to cleft lip with or without cleft palate.

Phase-Sensitive Amplified Transmission Links for Improved Sensitivity and Nonlinearity Tolerance

In this paper, we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description, we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations, and in particular, we show the possibility of efficiently mitigating both self-phase modulation (SPM)-induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation, the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to precompensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of $1\times 10^{-3}$ .

Association analysis of PTPN22, CTLA4 and IFIH1 genes with type 1 diabetes in Colombian families.

Protein tyrosine phosphatase, non-receptor type 22 (lymphoid) (PTPN22), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), and interferon induced with helicase C domain 1 (IFIH1) are among the confirmed type 1 diabetes (T1D) susceptibility genes in several populations. The aim of this study was to evaluate the role of PTPN22, CTLA4, and IFIH1 gene variants in the development of T1D in a Colombian population. Associations of PTPN22, CTLA4, and IFIH1 variants with T1D were investigated in a sample of 197 nuclear families, including 205 affected children, in the Colombian population. Three to four single nucleotide polymorphisms (SNPs) were analyzed per gene: rs2476600, rs2476601, rs1217418, and rs2488457 for PTPN22; rs1990760, rs3747517, and rs10930046 for IFIH1; and rs231775, rs3087243, and rs231779 for CTLA4. A transmission disequilibrium test was performed for the global sample, in addition to stratified analysis considering autoimmunity, age at onset, and parent of origin. Haplotypes per gene were also analyzed. There was no significant transmission distortion for CTLA4. Conversely, SNPs rs10930046 (IFIH1) and rs2476601 (PTPN222) exhibited significant transmission distortion of the C and T alleles, respectively, from parents to affected children (odds ratio [OR] 0.57 and 1.83, respectively). In addition, decreased transmission of the C allele for rs10930046 occurred preferentially from mothers. Stratification analysis revealed that this association was maintained in individuals who were positive for autoantibodies and in those with an age of diagnosis <5 years. The results show that IFIH1 and PTPN22 are associated with T1D in Colombian families.

Optical Fiber Dispersion Compensation Based on Optic System

In the optical fiber communication system of high-speed and large capacity, the dispersion is one of the main technical indicators. The dispersion causes the light pulse broadening, so it leads to the distortion of signal transmission and BER (bit error rate). The main research is the single-mode optical fiber dispersion compensation. The design and performance of system structure on the dispersion compensation fiber communication system is accomplished by using of the optic system optical fiber communication system simulation. Through the analysis of system structure and the research of the performance of the key components of the system, the output signal waveform is simulated and the influence of the output signal waveform by the system structure and key components performance of the receiving end is compared. The design can reduce the system dispersion.

The Kitchen Vehicle Pressure Autocontrol System Based on SC-UWB Technology of Internet Things

This research was carried out according to the actual needs of plateau kitchen vehicle. However, these military equipments have played important roles in the military exercises, earthquake relief, and other major activities, they does need urgent improvements in the using process. Among those problems to be solved, drift distortion of pressure cooker signal transmission on account of low temperature of high altitude, inability of achieving accurate control, and untimely feedback of service demand included. The pressure automatic control system of plateau kitchen vehicle which is based on Single Carrier Ultra Wide Band (UWB) wireless technology (SC-UWB), will completely solve the above problems, and the followings are innovations of this study: Firstly, Single-carrier ultra-wideband wireless transmission technology was used in this study, which was in accordance with Chinese Standard and based on chips produced by China. This would satisfy the needs of real-time transmission in pressure and temperature information under extreme environment, and solve technical problems such as signal integrity and communicational confidentiality, and this would also eliminate technical problems such as signal distortion, hysteresis, drift, high deviation repeatability of automatic control system of plateau kitchen vehicle in extreme environment. Secondly, intelligent sensor systems were connected to the Internet of things (IOT). To develop Industrial Personal Computer (IPC) according to the management system and daily use of this equipment and to lead the equipment to have node function of access to the Internet of things, would be the foundation of all kinds of beneficial exploration in the management of Internet of things, and also the guarantee of technology standard of Internet of things in military equipment of future. Then, the existing equipment can smoothly be switched in to avoid duplication of investment.