Robust backstepping for the Euler approximate model of sampled-data strict-feedback systems

Stabilization of uncertain sampled-data strict-feedback systems is addressed. The stability study is carried out on the Euler approximation of the exact discretized model of the plant. Firstly, a class of state-feedback controllers is developed that guarantees an input-to-state stability property for the closed-loop system. Additionally, assuming some hypotheses on the uncertain terms hold, a practical asymptotic stability property is ensured by designing an appropriate class of controllers.     

Transparent Nanocrystalline Glass-Ceramic System for Organic Pollutants Degradation

Because of the superior photocatalytic activities of nanocrystalline TiO₂ and ZnO under UV irradiation, they were embedded into the glass system (SiO₂, TiO₂, ZnO, B₂O₃, Na₂O, K₂O, P₂O₅, Li₂O and BaO) to provide easy separation from the aqueous system. Different contents of TiO₂ and ZnO have been investigated. Conversion to glass-ceramic materials was carried out by heat treatment at 450 °C, which is the onset of the nucleation peak according to the differential thermal analysis (DTA) result, for different times. This heat treatment regime preserves the transparency of the prepared materials in the visible region and good absorption in the UV region. The high content of TiO₂ or ZnO caused an improvement of microhardness of the prepared materials, though the presence of the two oxides with the same ratio decreased the microhardness values. Photocatalytic activity of the prepared glass-ceramic materials was investigated according to their efficiency for the degradation of humic acid (HA), the major precursor of disinfection by-products (DBPs), from water. All samples were proved to be photoactive with different extents. Four hours heat treatment at 450 °C appears to be the best conditions for the development of TiO₂ and ZnO crystals leading to better photocatalytic activity.     

Structurally Diverse Histone Deacetylase Photoreactive Probes: Design,Synthesis, and Photolabeling Studies in Live Cells and Tissue

Histone deacetylase (HDAC) activity is modulated in vivo by post-translational modifications and formation of multiprotein complexes. Novel chemical tools to study how these factors affect engagement of HDAC isoforms by HDAC inhibitors (HDACi) in cells and tissues are needed. In this study, a synthetic strategy to access chemically diverse photoreactive probes (PRPs) was developed and used to prepare seven novel HDAC PRPs 9 – 15 . The class I HDAC isoform engagement by PRPs was determined in biochemical assays and photolabeling experiments in live SET-2, HepG2, HuH7, and HEK293T cell lines and in mouse liver tissue. Unlike the HDAC protein abundance and biochemical activity against recombinant HDACs, the chemotype of the PRPs and the type of cells were key in defining the engagement of HDAC isoforms in live cells. Our findings suggest that engagement of HDAC isoforms by HDACi in vivo may be substantially modulated in a cell- and tissue-type-dependent manner.     

Characterization and Performance Analysis of LTE-Advanced Uplink Signals in Presence of Amplifier Nonlinearity

Carrier aggregation (CA) is the new technique standardized for the next generation of cellular networks, namely long term evolution-advanced (LTE-Advanced) in response to the continuous demands of increased data rates. One of the challenges facing the new CA technique is the increased dynamic range of the transmitted uplink (UL) signal that represents the sum of different carrier components in the time domain. This increased dynamic range makes the signal more susceptible to nonlinear distortion caused by nonlinear devices at the transmitter and eventually leads to performance degradation. In this paper, we investigate the effect of the nonlinear distortion on the UL of LTE-Advanced. Towards this investigation, statistical characterization of the UL signal is conducted, where it is established that it has a quasi-Gaussian characteristics. Also, statistical characterization of the nonlinear distortion noise at the receiver detector is performed, where it appears evident that it can be regarded as a complex Gaussian process. Through these characterizations, an analytical expression for the bit error rate, as a function of the system parameters and the input back-off level, is derived. The analytical results are validated via simulation results, where the good agreements confirm the pursued approach and the taken assumptions.     

Ethanol from lactose in salted cheese whey by recombinant Saccharomyces cerevisiae

Seven yeast recombinants were selected from 57 fusant colonies on the basis of higher DNA content, nuclear diameter and ethanol yield compared to parental Saccharomyces cerevisiae ATCC 4126 and Kluyveromyces lactis CBS 683. Six recombinants out of the above colonies revealed growth on lactose and sucrose, indicating that they are S. cerevisiae with transformed β-galactosidase systems. The fusant colonies were investigated with respect to their capacity to convert lactose in salted cheese whey into ethanol. Among these recombinants that showed high tolerance towards sodium chloride and higher ethanol yield than lactose fermenting parental K. lactis CBS 683, SK-1 exhibited high tolerance up to 4 g dl^–1 sodium chlonride with an ethanol yield of 4.66 ml dl^–1 (v/v) , SK-23 tolerated 6 g dl^–1 sodium chloride with an ethanol yield of 4.14 ml dl^–1 (v/v) and SK-26 showed resistance towards 8 g dl^–1 sodium chloride and give an ethanol yield of 3 ml dl^–1 (v/v).     

Ring of Masters (ROM): A new ring structure for Bluetooth scatternets with dynamic routing and adaptive scheduling schemes

This paper attempts to address the scatternet problem in Bluetooth through a comprehensive approach. We propose a new decentralized ring structure to combat the formation of traffic bottlenecks. The adopted construction protocol ensures flexibility of node selection and a good level of fault tolerance. The routing protocol combines both simplicity and robustness by taking advantage of the ring structure and relying on the collective memory of piconets to make forwarding and discarding decisions. The intra- and inter-piconet scheduling algorithm, called ROM adaptive scheduling (RAS), dynamically allocates time slots and is responsive to the varying workload conditions. We demonstrate, through analysis and simulations, that the various components of ROM yield a system that has good performance in terms of throughput, latency, delivery, and link utilization.     

A new taxonomy of routing algorithms for wireless mobile ad hoc networks: the component approach

Over the past decade, wireless multihop ad hoc networks have received a tremendous amount of research focus, at the core of which lies the design problem for efficient routing algorithms to meet various scenarios and applications. The axiom, "one size doesn't fit all," continues to stand firmly to this day. In light of this, we introduce a new routing design concept - the component approach. We examine existing routing protocols and break them down into smaller building blocks, namely, routing components. The component analysis and classification results show that most routing protocols can be functionally decomposed into several basic routing components. This fact indicates that it is feasible to design a component-based routing (CBR) protocol. With a different realization for each basic routing component, it is expected that the routing behavior of CBR can be tailored to different application profiles and time-varying environment parameters at a reasonable cost     

Load-Balanced Sparse Matrix–Vector Multiplication on Parallel Computers

We considered the load-balanced multiplication of a large sparse matrix with a large sequence of vectors on parallel computers. We propose a method that combines fast load-balancing with efficient message-passing techniques to alleviate computational and inter-node communications challenges. The performance of the proposed method was evaluated on benchmark as well as on synthetically generated matrices and compared with the current work. It is shown that, by using our approach, a tangible improvement over prior work can be obtained, particularly for very sparse and skewed matrices. Moreover, it is also shown that I/O overhead for this problem can be efficiently amortized through I/O latency hiding and overall load-balancing.     

Field Evaluation of Surge and Continuous Flows in Furrow Irrigation Systems

The objective of this paper is to study the performance of surgeand continuous furrow irrigation based on field experiments. Theexperiments took place on two farms located in the State of NewMexico, U.S.A., cultivated with Beans and Alfalfa and havingdifferent types of soil. Each farm was divided into two parts,where the first was designed to practice surge and the secondcontinuous irrigation. The analysis of the results showed thatsurge flow proides the desired crop water requirement at almost40% saving in water and time as well as improving the distribution uniformity and application efficiency of irrigation to about 90%.