Robustness maximization of parallel multichannel systems

Bit error rate (BER) minimization and SNR-gap maximization, two robustness optimization problems, are solved, under average power and bit-rate constraints, according to the waterfilling policy. Under peak-power constraint the solutions differ and this paper gives bit-loading solutions of both robustness optimization problems over independent parallel channels. The study is based on analytical approach with generalized Lagrangian relaxation tool and on greedy-type algorithm approach. Tight BER expressions are used for square and rectangular quadrature amplitude modulations. Integer bit solution of analytical continuous bit-rates is performed with a new generalized secant method. The asymptotic convergence of both robustness optimizations is proved for both analytical and algorithmic approaches. We also prove that, in conventional margin maximization problem, the equivalence between SNR-gap maximization and power minimization does not hold with peak-power limitation. Based on a defined dissimilarity measure, bit-loading solutions are compared over power line communication channel for multicarrier systems. Simulation results confirm the asymptotic convergence of both allocation policies. In non asymptotic regime the allocation policies can be interchanged depending on the robustness measure and the operating point of the communication system. The low computational effort of the suboptimal solution based on analytical approach leads to a good trade-off between performance and complexity.Comment: 27 pages, 8 figures, submitted to IEEE Trans. Inform. Theor

Coded Adaptive Linear Precoded Discrete Multitone Over PLC Channel

Discrete multitone modulation (DMT) systems exploit the capabilities of orthogonal subcarriers to cope efficiently with narrowband interference, high frequency attenuations and multipath fadings with the help of simple equalization filters. Adaptive linear precoded discrete multitone (LP-DMT) system is based on classical DMT, combined with a linear precoding component. In this paper, we investigate the bit and energy allocation algorithm of an adaptive LP-DMT system taking into account the channel coding scheme. A coded adaptive LPDMT system is presented in the power line communication (PLC) context with a loading algorithm which accommodates the channel coding gains in bit and energy calculations. The performance of a concatenated channel coding scheme, consisting of an inner Wei's 4-dimensional 16-states trellis code and an outer Reed-Solomon code, in combination with the proposed algorithm is analyzed. Theoretical coding gains are derived and simulation results are presented for a fixed target bit error rate in a multicarrier scenario under power spectral density constraint. Using a multipath model of PLC channel, it is shown that the proposed coded adaptive LP-DMT system performs better than coded DMT and can achieve higher throughput for PLC applications

A Coded Bit-Loading Linear Precoded Discrete Multitone Solution for Power Line Communication

Linear precoded discrete multitone modulation (LP-DMT) system has been already proved advantageous with adaptive resource allocation algorithm in a power line communication (PLC) context. In this paper, we investigate the bit and energy allocation algorithm of an adaptive LP-DMT system taking into account the channel coding scheme. A coded adaptive LP-DMT system is presented in the PLC context with a loading algorithm which ccommodates the channel coding gains in bit and energy calculations. The performance of a concatenated channel coding scheme, consisting of an inner Wei's 4-dimensional 16-states trellis code and an outer Reed-Solomon code, in combination with the roposed algorithm is analyzed. Simulation results are presented for a fixed target bit error rate in a multicarrier scenario under power spectral density constraint. Using a multipath model of PLC channel, it is shown that the proposed coded adaptive LP-DMT system performs better than classical coded discrete multitone

Minimisation du TEB moyen d'un système OFDM precodé

International audienceLe problème de la minimisation du TEB (taux d'erreur binaire) moyen est étudié pour un système LP-OFDM (linear precoded orthogonal frequency division multiplexing). Les algorithmes d'allocation des ressources sont proposés pour minimiser le TEB moyen sous contrainte de débit cible et de densité spectrale de puissance. Les résultats sont présentés dans le contexte des courants porteurs en ligne (CPL) et comparés aux performances des algorithmes, plus classiques, de maximisation de la marge des systèmes OFDM et LP-OFDM. Il est montré que l'allocation proposée est plus performante surtout pour les faibles RSB (rapport signal sur bruit) tout en offrant une complexité réduite

Minimisation du TEB moyen d'un système OFDM precodé

International audienceLe problème de la minimisation du TEB (taux d'erreur binaire) moyen est étudié pour un système LP-OFDM (linear precoded orthogonal frequency division multiplexing). Les algorithmes d'allocation des ressources sont proposés pour minimiser le TEB moyen sous contrainte de débit cible et de densité spectrale de puissance. Les résultats sont présentés dans le contexte des courants porteurs en ligne (CPL) et comparés aux performances des algorithmes, plus classiques, de maximisation de la marge des systèmes OFDM et LP-OFDM. Il est montré que l'allocation proposée est plus performante surtout pour les faibles RSB (rapport signal sur bruit) tout en offrant une complexité réduite

Determination of chest x-ray cost using activity based costing approach at Penang General Hospital, Malaysia

Background: Activity based costing (ABC) is an approach to get insight of true costs and to solve accounting problems. It provides more accurate information on product cost than conventional accounting system. The purpose of this study was to identify detailed resource consumption for chest x-ray procedure. Methods: Human resource cost was calculated by multiplying the mean time spent by employees doing specific activity to their per-minute salaries. The costs of consumables and clinical equipments were obtained from the procurement section of the Radiology Department. The cost of the building was calculated by multiplying the area of space used by the chest X-ray facility with the unit cost of public building department. Moreover, straight-line deprecation with a discount rate of 3% was assumed for calculation of equivalent annual costs for building and machines. Cost of electricity was calculated by multiplying number of kilo watts used by electrical appliance in the year 2010 with electricity tariff for Malaysian commercial consumers (MYR 0.31 per kWh). Results: Five activities were identified which were required to develop one chest X-ray film. Human resource, capital, consumable and electricity cost was MYR 1.48, MYR 1.98, MYR 2.15 and MYR 0.04, respectively. Total cost of single chest X-ray was MYR 5.65 (USD 1.75). Conclusion: By applying ABC approach, we can have more detailed and precise estimate of cost for specific activity or service. Choice of repeating a chest X-ray can be based on our findings, when cost is a limiting factor. Pan African Medical Journal 2012; 12:4

How to Retain the ‘Core- Employees’ Through HR Practices? An Empirical Study of Public & Private Sector Universities of Khyber Pakhtunkhwa (KP), Pakistan

This study investigates the influence and effectiveness of Human Resource Management Practices which will help organization to sustain the “core-employees”.  Employee retention is one of the challenges facing many business organizations today. This empirical study examined the current Human Resource Management practices in Higher education institution of Khyber Pakhtunkhwa. In particular, the study identifies those elements of HRM, which strongly influence the “Core-employees” to stay in the organization, because organizations inclination now days depend on upon knowledge base human capital and due to the emergence of new Public & Private sector universities in Khyber Pakhtunkhwa, most of the universities are facing employees turnover. In this study employee of both Public & Private sector universities of Khyber Pakhtunkhwa is targeted, in order to extract information regarding HRM practices that which factor significantly influence these core employees to stay in the organization. For this study One hundred and thirty participants were selected from thirteen Public and Private sectors universities of Khyber Pakhtunkhwa. Through stratified random sampling method. The constructs of the study were measured using five-point Likert rating scale. Keywords: Employees Retention, HRM Practices, Core employees, Reward and Recognition, Compensation

Mean BER minimization loading algorithm for linear precoded OFDM

ISBN: 978-1-4244-3381-0International audienceThe problem of minimization of mean bit error rate (BER) of a linear precoded orthogonal frequency division multiplexing ({LP-OFDM}) system is considered. The discrete bit loading algorithms are proposed, which minimize the mean BER of the system for a target bit rate under a peak power constraint. The results are shown for a power line communication system using a well-known multipath channel model. The other, more common, robustness optimization problem is the margin maximization. The obtained results are compared with those of the margin maximization for both {OFDM} and {LP-OFDM} schemes. It is shown that the proposed {LP-OFDM} allocation performs better than the previously published algorithms for poor SNR. Moreover, it is observed that the {LP-OFDM} allocations have lower computational complexity than the {OFDM} allocations

Atraumatic Splenic Rupture after Myocardial Infarction

Atraumatic splenic rupture is a rare but potentially life-threatening event. It mostly happens when the spleen is already diseased; however, sometimes it can be drug induced in a previously normal spleen. Although anticoagulation has been attributed to spontaneous splenic rupture quite frequently, the role of dual antiplatelet therapy is underestimated. We report a case of an 80-year-old woman who developed spontaneous splenic rupture 4 weeks after starting dual antiplatelet therapy

Video-FocalNets: Spatio-Temporal Focal Modulation for Video Action Recognition

Recent video recognition models utilize Transformer models for long-range spatio-temporal context modeling. Video transformer designs are based on self-attention that can model global context at a high computational cost. In comparison, convolutional designs for videos offer an efficient alternative but lack long-range dependency modeling. Towards achieving the best of both designs, this work proposes Video-FocalNet, an effective and efficient architecture for video recognition that models both local and global contexts. Video-FocalNet is based on a spatio-temporal focal modulation architecture that reverses the interaction and aggregation steps of self-attention for better efficiency. Further, the aggregation step and the interaction step are both implemented using efficient convolution and element-wise multiplication operations that are computationally less expensive than their self-attention counterparts on video representations. We extensively explore the design space of focal modulation-based spatio-temporal context modeling and demonstrate our parallel spatial and temporal encoding design to be the optimal choice. Video-FocalNets perform favorably well against the state-of-the-art transformer-based models for video recognition on five large-scale datasets (Kinetics-400, Kinetics-600, SS-v2, Diving-48, and ActivityNet-1.3) at a lower computational cost. Our code/models are released at https://github.com/TalalWasim/Video-FocalNets.Comment: Accepted to ICCV-2023. Camera-Ready version. Project page: https://TalalWasim.github.io/Video-FocalNets