Efficient Federated Learning over Multiple Access Channel with Differential Privacy Constraints

In this paper, the problem of federated learning (FL) through digital communication between clients and a parameter server (PS) over a multiple access channel (MAC), also subject to differential privacy (DP) constraints, is studied. More precisely, we consider the setting in which clients in a centralized network are prompted to train a machine learning model using their local datasets. The information exchange between the clients and the PS takes places over a MAC channel and must also preserve the DP of the local datasets. Accordingly, the objective of the clients is to minimize the training loss subject to (i) rate constraints for reliable communication over the MAC and (ii) DP constraint over the local datasets. For this optimization scenario, we proposed a novel consensus scheme in which digital distributed stochastic gradient descent (D-DSGD) is performed by each client. To preserve DP, a digital artificial noise is also added by the users to the locally quantized gradients. The performance of the scheme is evaluated in terms of the convergence rate and DP level for a given MAC capacity. The performance is optimized over the choice of the quantization levels and the artificial noise parameters. Numerical evaluations are presented to validate the performance of the proposed scheme

Spa Revenue Management

In principle, spa managers should be able to apply revenue management to spa operations. To do so, however, requires a revision in the way most spas traditionally have viewed sales. Most spa managers track appointments and customer needs, but instead they need to focus specifically on the time element involved in their services. A time-related measure, revenue per available treatment-hour (RevPATH), integrates the price and duration of the treatment as factors in the revenue calculation. Certain elements of current-day spa practice, such as discounting and managing treatment duration, carry the seeds of revenue management, but those are often implemented as tactical measures during particularly slow or busy times. Few spas have established the necessary strategic approach to assemble those tactics into a coherent revenue management strategy. This report establishes a framework for implementing a spa revenue management strategy and sets a practical road map for its execution

Burning behavior of aramid and FR viscose blended fabrics

Two sets of yarns have been produced on ring spinningsystem. In the first set, flame-retardant viscose and meta-aramidare blended in three different ratios of 30:70, 50:50 and 70:30, andin the second set, flame-retardant viscose, nylon 66 and metaaramidare blended in two different ratios of 30:20:50 and50:20:30 respectively. These yarns are converted in to wovenfabrics and evaluated for limiting oxygen, contact heat, radianheat and convective heat indices. One way analysis of variance(ANOVA) has been applied to find out the effect of different fibreblends on various flame and thermal properties. It is observed thatthere is relationship between fibre contents in the blend and flameand thermal resistant properties

Thermal, mechanical and comfort performance of various modacrylic fibre blended fabric

In this study, various blended fabrics of modacrylic fibre with flame retardant (FR) viscose, and Nylon 66 have been manufactured and studied for their thermal, mechanical and comfort properties for workers of oil & gas industry. The ring spinning system is used to manufacture three sets of yarns. In the first set, three yarns are produced using only modacrylic, only FR viscose, and only Nylon 66 fibres. The second set of yarns is made using blends of FR viscose and modacrylic. These fibres are blended in three different ratios of 30:70, 50:50 and 70:30 for making yarns. The third set is made out of tertiary blends of FR viscose, nylon 66 and modacrylic. These are blended in two different ratios of 30:20:50 and 50:20:30 respectively. Fabric samples have been produced out of these yarns and evaluated for their flame, thermal and mechanical properties after 5 and 50 washes. The radiant heat transfer index and convective heat transfer index of blends of modacrylic fibre are found in the range 12 - 13.5 s and 5.0 - 5.7 s respectively. Multivariate test analysis has been applied to find out the effect of different fibre blends on various flame and thermal properties. The study shows that flame and thermal resistant properties are influenced by fibre blending ratio.

Effect of Raman pump direction on conventional multiwavelength Brillouin-Raman fiber laser

We have experimentally investigated the effects of Raman pump direction on the performance of multiwavelength Brillouin-Raman fiber laser. Comparison of Raman gain profiles at different Raman pump direction demonstrates higher gain in backward-pumping scheme than that in the forward pumping configuration. 192 channels at the typical Brillouin shifted frequency spacing of 10 GHz are attained through backward pumping due to the higher Raman gain. On the other hand, forward-pumping scheme produces better optical signal-to-noise ratio of 26 dB with 20 GHz channel spacing

OSNR enhancement utilizing large effective area fiber in a multiwavelength Brillouin-Raman fiber laser.

We propose a simple Brillouin-Raman multichannel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels

Transposon activation mutagenesis as a screening tool for identifying resistance to cancer therapeutics

Background: The development of resistance to chemotherapies represents a significant barrier to successful cancer treatment. Resistance mechanisms are complex, can involve diverse and often unexpected cellular processes, and can vary with both the underlying genetic lesion and the origin or type of tumor. For these reasons developing experimental strategies that could be used to understand, identify and predict mechanisms of resistance in different malignant cells would be a major advance. Methods: Here we describe a gain-of-function forward genetic approach for identifying mechanisms of resistance. This approach uses a modified piggyBac transposon to generate libraries of mutagenized cells, each containing transposon insertions that randomly activate nearby gene expression. Genes of interest are identified using next-gen high-throughput sequencing and barcode multiplexing is used to reduce experimental cost. Results: Using this approach we successfully identify genes involved in paclitaxel resistance in a variety of cancer cell lines, including the multidrug transporter ABCB1, a previously identified major paclitaxel resistance gene. Analysis of co-occurring transposons integration sites in single cell clone allows for the identification of genes that might act cooperatively to produce drug resistance a level of information not accessible using RNAi or ORF expression screening approaches. Conclusion: We have developed a powerful pipeline to systematically discover drug resistance in mammalian cells in vitro. This cost-effective approach can be readily applied to different cell lines, to identify canonical or context specific resistance mechanisms. Its ability to probe complex genetic context and non-coding genomic elements as well as cooperative resistance events makes it a good complement to RNAi or ORF expression based screens

Multiwavelength Brillouin-Raman fiber laser assisted by Rayleigh scattering

Multiwavelength fiber lasers based on hybrid Brillouin-Raman gain configuration supported by Rayleigh scattering effect have attracted significant research interest due to the large numbers of channel generation from a single light source. When narrow bandwidth Brillouin gain combines with broad bandwidth Raman gain, hundreds of channels would be generated. In multiwavelength Brillouin–Raman fiber laser (MBRFL) architectures, dispersion compensated fiber is utilized as the nonlinear gain media. When a single laser launches into a distributed Raman gain area, it grows very fast through stimulated Raman scattering, and when it acquires threshold condition, it isback-scattered through nonlinear Brillouin and Rayleigh effects, inelastically and elastically inside the gain media respectively. After scattered lights experience amplification through stimulated Raman and Brillouin amplification, they saturate and consequently back-scatter once more. This phenomenon is dubbed as self-feedback seeding-effect which is the main principle of MBRFL generation. Normally, the other nonlinear effects such as four waves mixing is assisted by distributed Raman amplifier which generates self-lasing cavity modes that lead to the formation of turbulent waves. The interaction between laser cavity lines and the turbulent waves causes spectral broadening of laser lines that has a direct impact on the quality of Brillouin Stokes lines in terms of Stokes-optical signal to noise ratio (S-OSNR). In this work, it is proven that utilizing large effective area fiber (LEAF) in MBRFL enhances the S-OSNR of Brillouin Stokes lines effectively. Consequently, LEAF is used in the aim of suppressing the noise. In all the experiments which have done in this work, Brillouin pump power is fixed on higher level (8 dBm) due to producing the higher stimulated Brillouin scattering. However Raman pump power and Raman pump direction are two critical features which are studied in this thesis, since they play significant role in the MBRFL characteristics performances. Generation of flat amplitude MBRFL comprises higher number of channels with acceptable S-OSNR utilizing a single frequency Raman pump is the main objective of this research. Investigation and improvement of the characteristics of MBRFL utilizing LEAF is another aim of this work. In this work the optical characteristic performances of generated MBRFL output spectrum at three different configuration; conventional-MBRFL (CON-MBRFL), double-pass MBRFL (DP-MBRFL) and new forward-backward scattering combination-MBRFL (FBSCMBRFL) are investigated at different Raman pump powers and directions. It is obtainedthat the forward pumping scheme of CON-MBRFL configuration capable to produce flat amplitude MBRFL with 20 GHz channels spacing. Maximum 322 channels with acceptable average S-OSNR about 16 dB has been created with this structure, when 1525 nm Brillouin pump wavelength is launched into the linear cavity. In addition, 258 channels with 26 dB SOSNR, excellent uniformity, identical Stokes peak power and linewidth are generated via utilizing backward-Raman pumping scheme of DP-MBRFL configuration. Moreover, it is found that the new configuration FBSC-MBRFL is capable to enhance the Stokes lines count to 700 channels while a single forward-Raman pumping scheme is applied with 1 W power