Carrier recovery techniques on satellite mobile channels

An analytical method and a stored channel model were used to evaluate error performance of uncoded quadrature phase shift keying (QPSK) and M-ary phase shift keying (MPSK) trellis coded modulation (TCM) over shadowed satellite mobile channels in the presence of phase jitter for various carrier recovery techniques

Hemijski aspekt uticaja jona kobalta na aktivnost ATP-aza

The influence of Co2+ ions on the activities of Na+/K+-ATPase and Mg2+-ATPase, enzymes from rat brain synaptic plasma membrane, was studied. The aim of this study was to investigate the inhibition of both ATPases activities by exposure to cobalt ions as a function of experimentally added CoSO4. The "free" Co2+ concentrations in the reaction mixture were also calculated and discussed. CoSO4 induced a dose-dependent inhibition of both enzymes. The IC50 values of Co2+, as calculated from the experimental curves, were 168 mu M for Na+/K+-ATPase and 262 mu M for Mg2+-ATPase, and for the recalculated free Co2+ concentration 75.4 mu M for Na+/K+-ATPase and 136 mu M for Mg2+-ATPase. The obtained linear Dixon's plot for Na+/K+-ATPase implies equilibrium binding of cobalt with inhibitory sites on the enzyme. The kinetic parameters for both enzymes in presence and absence of CoSO4 were calculated from the experimental data. The results of the kinetic analysis show that inhibition of Na+/K+-ATPase induced by CoSO4 is non-competitive, and for Mg2+-ATPAse that there are two sites of different sensitivities or two different enzymes.Ispitan je uticaj Co2+ jona na aktivnost Na+/K+ -ATPaze i Mg2+ -ATP-aze, enzima sinaptozomalne membrane mozga pacova. Cilj rada je bio da se ispita inhibicija aktivnosti oba enzima izazvana izlaganjem jonima kobalta kao funkcija eksperimentalno dodatog CoSO4. Takođe je izračunata i diskutovana "slobodna" koncentracija Co2+ u reakcionoj smeši. Utvrđeno je da kobalt inhibira enzime u koncentraciono zavisnom smislu. Vrednosti IC50 izračunate iz eksperimentalnih krivih su: 168 μM za Na+/K+ -ATP-azu i 136 μM za Mg2+ -ATP-azu. Linearan Dixon-ov plot za Na+/K+ -ATP-azu ukazuje na ravnotežno vezivanje kobalta. Izračunati su kinetički parametri oba enzima u prisustvu i odsustvu CoSO4. Inhibicija Na+/K+-ATP-aze izazvana CoSO4 je nekompetitivna, dok Mg2+ -ATP-aza ima dva mesta vezivanja različitog afiniteta ili pak dva različita enzima

Design and performance analysis of network code division multiplexing for wireless sensor networks

© 2015 IEEE. In this paper, we investigate the performance of a wireless sensor network, in which multiple groups of source nodes communicate with their respective destination nodes with the help of a common relay network. A network code division multiplexing (NCDM) scheme is proposed to remove the inter-session interference among multiple transmission sessions at each destination. We focus on analyzing the soft processing algorithm of the NCDM scheme. Based on the analysis results, a new code design criteria for the construction of the generator matrix is proposed. Simulation results show that by following the proposed code design criteria, the bit error ratio (BER) performance gap between the scheme we studied and the serial session scheme can be managed effectively. In serial session scheme, source nodes in a number of groups communicate with their respective destinations in a time division manner

Network coded non-binary LDGM codes based on lattices for a multi-access relay system

© 2015 IEEE. In this paper, we propose a novel network coded non-binary low-density generator matrix (LDGM) code structure for a multi-access relay system, where multiple sources transmit lattice signals to a destination with the help of a relay. Specifically, we first develop a network coded non-binary LDGM code structure by jointly considering lattice-signal transmissions at the sources and the relay. Then we derive the achievable computation rate (ACR) for the proposed system and on that basis optimize the key parameters in the proposed structure to maximize the ACR. Furthermore, we optimize the network coded non-binary LDGM codes based on lattices to approach the ACR. Simulation results show that the optimal setting of the parameters is consistent with that obtained from our analysis and the proposed code structure outperforms the designed reference scheme

Short Block-length Codes for Ultra-Reliable Low-Latency Communications

This paper reviews the state of the art channel coding techniques for ultra-reliable low latency communication (URLLC). The stringent requirements of URLLC services, such as ultra-high reliability and low latency, have made it the most challenging feature of the fifth generation (5G) mobile systems. The problem is even more challenging for the services beyond the 5G promise, such as tele-surgery and factory automation, which require latencies less than 1ms and failure rate as low as $10^{-9}$. The very low latency requirements of URLLC do not allow traditional approaches such as re-transmission to be used to increase the reliability. On the other hand, to guarantee the delay requirements, the block length needs to be small, so conventional channel codes, originally designed and optimised for moderate-to-long block-lengths, show notable deficiencies for short blocks. This paper provides an overview on channel coding techniques for short block lengths and compares them in terms of performance and complexity. Several important research directions are identified and discussed in more detail with several possible solutions.Comment: Accepted for publication in IEEE Communications Magazin

Efficient Fine-Tuning of Compressed Language Models with Learners

Fine-tuning BERT-based models is resource-intensive in memory, computation, and time. While many prior works aim to improve inference efficiency via compression techniques, e.g., pruning, these works do not explicitly address the computational challenges of training to downstream tasks. We introduce Learner modules and priming, novel methods for fine-tuning that exploit the overparameterization of pre-trained language models to gain benefits in convergence speed and resource utilization. Learner modules navigate the double bind of 1) training efficiently by fine-tuning a subset of parameters, and 2) training effectively by ensuring quick convergence and high metric scores. Our results on DistilBERT demonstrate that learners perform on par with or surpass the baselines. Learners train 7x fewer parameters than state-of-the-art methods on GLUE. On CoLA, learners fine-tune 20% faster, and have significantly lower resource utilization.Comment: 8 pages, 9 figures, 2 tables, presented at ICML 2022 workshop on Hardware-Aware Efficient Training (HAET 2022

Material Modelling of Short Fiber Reinforced Thermoplastic for the FEA of a Clinching Test

In modern car body construction, multi-material and hybrid design is used, whereby short fibre reinforced plastics combined with light metals represent an interesting class of work-piece materials. In order to realize modern hybrid construction, suitable joining techniques are therefore required. Clinching represents a cost-effective and easy to implement joining method. In this paper the material modelling of the short fibre reinforced thermoplastic sheets considering the fibre orientation tensor for the FEA of the clinching process is presented

The design of degree distribution for distributed fountain codes in wireless sensor networks

In this paper, we first analyse bit error rate (BER) bounds of the distributed network coding (DNC) scheme based on the Luby-transform (LT) codes, which is a class of fountain codes, for wireless sensor networks (WSNs). Then we investigate the effect from two parameters of the degree distributions, i.e., the degree value and the proportion of odd degree, to the performance of the LT-based DNC scheme. Based on the analysis and investigation results, a degree distribution design criteria is proposed for the DNC scheme based on fountain codes over Rayleigh fading channels. We compare the performance of the DNC scheme based on fountain codes using degree distributions designed in this paper with other schemes given in the literature. The comparison results show that the degree distributions designed by using the proposed criteria have better performance

Increased Physical Activity and Reduced Pain with Spinal Cord Stimulation: a 12-Month Study

International Journal of Exercise Science 13(3): 1583-1594, 2020. The purpose of this study was to assess changes in pain and physical activity after replacing a traditional spinal cord stimulation (SCS) implantable pulse generator with a next generation SCS in patients for whom traditional SCS was no longer providing adequate relief of low back and/or leg pain. Subjects (n = 19) who reported that they were no longer receiving adequate relief from traditional SCS were implanted with a next generation SCS. Eighteen additional patients who were receiving relief from traditional SCS were also followed as a control. Both groups (next generation, traditional) were assessed for low-back and limb pain (visual analog scale) and daily physical activity (wearable accelerometer) at baseline and three, six, nine and 12 months following the SCS implant. Relative to baseline, next generation SCS subjects exhibited reductions (p ≤ 0.05 for all) in low-back pain (average reduction of 22%) at every time point, in leg pain (average reduction of 23%) at every time point except six months and increased physical activity (average increase of 57%) at three, six and nine months. As expected, there were no changes in pain or physical activity in the traditional SCS subjects (p ≥ 0.1). In conclusion, pain decreased, and physical activity increased in patients receiving a next generation SCS. Physical activity may serve as an objectively measured marker of pain

American power and identities in the age of Obama

Although the election of Barack Obama to the US presidency represents a landmark event in the history of that country, questions remain over its broader political significance. What is the likelihood of Obama's foreign and national security policies differing fundamentally from those of the Bush administrations Does Obama's election signal a post-racial phase in American national life What are the factors that suggest opportunities to change and expand American identities as opposed to those that limit Obama's sphere of action This article introduces the special issue and suggests that although Obama's room for manoeuvre is limited by legacies inherited from the Bush administration, Obama's own appointments to high office as well as other actions, despite the availability of alternative courses, indicate that he is not the transformational president he claimed to be. American identities, therefore, are deeply embedded and remain heavily imbued with racial, religious and imperial features