Airtime usage control in virtualized multi-cell 802.11 networks

This paper investigates the station (STA)-access point (AP) association and airtime control for virtualized 802.11 networks to provide service customization and fairness across multiple Internet service-providers (ISPs) sharing the common physical infrastructure and network capacity. More specifically, an optimization problem is formulated on the STAs' transmission probabilities to maximize the overall network throughput, while providing airtime usage guarantees for the ISPs. Subsequently, an algorithm to reach the optimal solution is developed by applying monomial approximation and geometric programming iteratively. Illustrative results confirm the superior and robust performance of the developed association and airtime control scheme in terms of both throughput and fairness

AP-STA association control for throughput maximization in virtualized WiFi networks

To manage and enable service customization among multiple internet service providers (ISPs) sharing the common physical infrastructure and network capacity in virtualized Wi-Fi networks, this paper models and optimizes access point-station (STA) association via airtime usage control. More specifically, an optimization problem is formulated on the STAs’ transmission probabilities to maximize the overall network throughput, while providing airtime usage guarantees for the ISPs. As the proposed optimization problem is inherently non-convex, an algorithm to reach the optimal solution is developed by applying monomial approximation and geometric programming iteratively. Based on the proposed 3-D Markov-chain model of the enhanced distributed channel access protocol, the detailed implementation of the optimal transmission probability of each STA is also discussed by manipulating medium access control parameters. The performance of the developed association and airtime control scheme is evaluated through numerical results. For both homogeneous and non-homogeneous STA distributions, numerical results reveal performance gains of the proposed algorithm in improving the throughput and keeping airtime usage guarantees

覚せい剤精神病脆弱性に於けるドーパミンD2、セロトニンS2受容体のポジトロンCTによる測定

研究科: 千葉大学大学院医学研究科千大院医博乙第1281

Study of AlGaN/GaN High-Electron-Mobility Transistors by Experiments and Simulations

Gallium nitride (GaN) is a semiconductor that possesses unique characteristics that make it advantageous for high power and high-frequency applications. There is an explosive evolution of nitride semiconductors in both optoelectronics and electronics in the last 30 years. However, some bottlenecks are blocking the pathway of GaN replacing the Si. This thesis addresses the experimental fabrication of Au-free ohmic contact. An Au-free ohmic contact on AlGaN/AlN/GaN heterostructures based on Ti/Al/Ta metal stack was realized using low annealing temperatures. The SiCl4 treatment at the contact region plays a critical role in improving the contact performance. The Au-free AlGaN/AlN/GaN HEMTs show a higher maximum drain current density and transconductance. This thesis also discussed the fabrication of normally-off AlGaN/GaN HEMTs. A normally-off AlGaN/GaN MIS-HEMTs is realized by BCl3/Cl2-based gate recessed dry etching. The threshold voltage is positively shifted by 6V while the gate current leakage is reduced by three orders. Finally, the theoretical discussion in improving the breakdown voltage of the GaN-based transistor is presented. The performances of the HEMT with gate grating field plate (GGFP), the HEMT with drain grating field plate (HEMT-D), and the HEMT with both gate and drain grating field plate (HEMT-GD) are analyzed based on the numerical calculations on Silvaco Atlas. The simulation results indicate the grating field plate at the gate or drain side can split the electric field peak, which further efficiently improves the breakdown voltage of the HEMT. Additionally, the optimization of the GGFP and DGFP design is discussed. The systematic study provides hints for future experimental realization

Real-time RT–PCR validation of the downregulated predicted miR-124 targets

<p><b>Copyright information:</b></p><p>Taken from "Systematic identification of microRNA functions by combining target prediction and expression profiling"</p><p>Nucleic Acids Research 2006;34(5):1646-1652.</p><p>Published online 20 Mar 2006</p><p>PMCID:PMC1405822.</p><p>© The Author 2006. Published by Oxford University Press. All rights reserved</p> The mRNA levels for downregulated targets at 4, 24 and 48 h were examined. The expression levels at 24 and 48 h are presented as percentages of that at 4 h. Among the validated targets, the microarray results indicated that genes 8801 and 8992 were first downregulated at 8 h; genes 8763, 3915, 6566, 9341, 10 449 and 10 634 were first downregulated at 16 h; genes 6836, 60 481 and 84 061 were first downregulated at 24 h; genes 27 230 and 55 225 were first downregulated at 32 h (downregulation is defined as at least 50% reduction of gene expression)

Exploiting multi-user diversity in wireless LANs with channel-aware CSMA/CA

This paper presents a channel-aware access scheme for Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) aiming to take advantage of multi-user diversity and improve throughput, while supporting distributed and asynchronous operation. By dynamically adjusting the contention window of each station (STA) according to its channel state, this method prioritizes STAs that gain most from using a channel, and hence, enhances channel utilization in comparison with a simple random access scheme. To model the proposed Adaptive CSMA/CA (A-CSMA/CA) protocol, a three-dimensional Markov chain is developed. With the aid of such model, performance of the proposed A-CSMA/CA is analytically studied in terms of saturation throughput. Furthermore, illustrative results confirm that A-CSMA/CA significantly improves the throughput, specifically in a large network

Additional file 1: of WU-CRISPR: characteristics of functional guide RNAs for the CRISPR/Cas9 system

Supplementary Tables S1–S3. (PDF 285 kb

DataDryad_OIK-05198.R2

DataDryad_OIK-05198.R

The top ten GeneGo pathways generated by MetaCore when the 20 overlapping genes were used.

<p>The top ten GeneGo pathways generated by MetaCore when the 20 overlapping genes were used.</p

The dynamics of infectious virus with respect to the accumulated infected population for different age groups.

<p>The dynamics of infectious virus with respect to the accumulated infected population for different age groups.</p