Typical Hybrid Research Articles

A Tutorial for Key Problems in the Design of Hybrid Hierarchical NoC Architectures with Wireless/RF

As processing nodes scale up, it is difficult for traditional electronic networks to supply on-chip communication efficiently due to unacceptable latency, plus power and area consumption. Alternative interconnects, such as radio frequency interconnect (RF-I) and optical interconnect, have been explored as interconnection backbones. Hybrid hierarchical architectures with both traditional interconnects and emerging interconnects have been widely adopted to get excellent trade-off between latency and power. The hybrid hierarchical architecture with a wireless/RF-I backbone is more cost-efficient and feasible due to advantages in complementary metal oxide semiconductor compatibility, compared with other alternative interconnects, and has become one of the mainstreams of chip multi-processor systems. However, how to efficiently utilize the wireless/RF-I backbone is a new challenge for designers. Based on analysis of existing typical hybrid hierarchal wireless/RF-I architectures (HHWAs), the key problems in the Design of HHWAs are proposed here, and related potential solutions are provided. In particular, strategies for resource management of wireless/RF-I are explored in detail, and different solutions are discussed. This work is expected to serve as a basis for future HHWA designs.

A Conductivity-Based Sensor for Detecting Micro-Water in On-Line Oil Analysis

Molecular water in lubricants causes unavoidable damage in mechanical tribo-systems. To illustrate the characteristics of water in oil, three typical hybrid states, including dissolved, free, and emulsified states, were discussed focusing on the physical structures, hazards, and electric properties. Aiming at the on-line monitoring of molecular water in engine oil, a conductivity-based sensor was proposed. Two enamel wires, with partial naked surfaces, were winded around an insulated pole in parallel to serve as a probe. A higher cell constant was obtained with a high sensitivity. A multi-channel sensor with four probes was designed for on-line monitoring. The performance of the sensor was examined experimentally. As main result, the sensor has explicit effects on detecting free and emulsified water. The sensor also has a good linearity and repeatability when water content increasing from 0% to 3%, and has a high reliability under the disturbances of air and metal debris.

Modelling and Analyzing Hybrid Electric Vehicles with Single and Dual Epicyclic Power Split Transmissions

The main aim of this paper is to investigate the performance of hybrid electrical vehicles (HEVs) using single and dual epicyclic power split transmissions (PST). The development of PST has been a crucial feature in the technological success of hybrid driveline vehicles. In this paper, single and twin epicyclic power split transmissions models are analyzed and the relationships of speed and torque of the engine, motor and generator are developed. The models are further extended to include all subsystems and a controller designer to be fitted in a typical hybrid electrical vehicle (HEV). Computer programmes for the analysis of epicyclic transmission based on a matrix method are developed and used. In addition, the performance and control strategy of the new system is presented. Three vehicle models are built-up; namely: traditional ICE vehicle, HEV with single epicyclic gearbox, and HEV with twin epicyclic gearbox. The vehicles are simulated over typical driving cycles. The results focus on fuel consumption comparisons but it is also shown how the single and twin epicyclic gearboxes use the engine and motor generator units differently. The simulations show that the twin epicyclic offers substantial improvements of reduction in energy consumption, though the benefits are sensitive to the driving cycle used.

Probabilistic modelling and analysis of stand-alone hybrid power systems

As a part of the Hybrid Intelligent Algorithm, a model based on an ANN (artificial neural network) has been proposed in this paper to represent hybrid system behaviour considering the uncertainty related to wind speed and solar radiation, battery bank lifetime, and fuel prices. The Hybrid Intelligent Algorithm suggests a combination of probabilistic analysis based on a Monte Carlo simulation approach and artificial neural network training embedded in a genetic algorithm optimisation model. The installation of a typical hybrid system was analysed. Probabilistic analysis was used to generate an input–output dataset of 519 samples that was later used to train the ANNs to reduce the computational effort required. The generalisation ability of the ANNs was measured in terms of RMSE (Root Mean Square Error), MBE (Mean Bias Error), MAE (Mean Absolute Error), and R-squared estimators using another data group of 200 samples. The results obtained from the estimation of the expected energy not supplied, the probability of a determined reliability level, and the estimation of expected value of net present cost show that the presented model is able to represent the main characteristics of a typical hybrid power system under uncertain operating conditions.

Freeway Off-Ramp and Downstream Intersection Coordination Based on MLD Model and MPC Approach

Urban traffic system is typical hybrid system. It is very difficult to coordinate the freeway off-ramp metering and downstream intersection signals which mean a special continuous-discrete-mixing traffic control model need to be considered. In this paper, taking queue length as continuous state variable, traffic signal as discrete variable and traffic count as continuous variable, Model Logic Dynamic approach is built for modeling. Then MILP optimization approach is applied to verify the rationality of the hybrid model. MATLAB simulation results show the MLD model and MILP based MPC method could be used for the coordination between off-ramp metering and downstream intersection signal very well.

Ordered Disorder of the Astrocytic Dystrophin-Associated Protein Complex in the Norm and Pathology

The abundance and potential functional roles of intrinsically disordered regions in aquaporin-4, Kir4.1, a dystrophin isoforms Dp71, α-1 syntrophin, and α-dystrobrevin; i.e., proteins constituting the functional core of the astrocytic dystrophin-associated protein complex (DAPC), are analyzed by a wealth of computational tools. The correlation between protein intrinsic disorder, single nucleotide polymorphisms (SNPs) and protein function is also studied together with the peculiarities of structural and functional conservation of these proteins. Our study revealed that the DAPC members are typical hybrid proteins that contain both ordered and intrinsically disordered regions. Both ordered and disordered regions are important for the stabilization of this complex. Many disordered binding regions of these five proteins are highly conserved among vertebrates. Conserved eukaryotic linear motifs and molecular recognition features found in the disordered regions of five protein constituting DAPC likely enhance protein-protein interactions that are required for the cellular functions of this complex. Curiously, the disorder-based binding regions are rarely affected by SNPs suggesting that these regions are crucial for the biological functions of their corresponding proteins.

Analysis and Simulation of Plant Type on Canopy Structure and Radiation Transmission in Rice

Three typical hybrid rice cultivars, together with three artificially modified plant types by the application of N fertilizer during the elongation of the two uppermost leaves were used to analyze how the plant type affected the layered leaf area and radiation transmission. Plant type factors, layered leaf area and radiation distribution were measured at the full heading, 10 d and 25 d after full heading stages, respectively. A model for calculating the layered leaf area from plant type factors was established and validated to determine the effects of plant type factors on the layered leaf area for the three hybrids. Furthermore, the relationship between layered leaf area and radiation transmission was established by using the radiation transmission model. The effects of the plant type factors on the radiation transmission for the three hybrids were evaluated by using this model. Finally, a method was established to describe the canopy structure, such as the layered leaf area index and the radiation distribution in the rice canopy.

ELECTROPHORETIC STUDIES OF HYBRIDS OF WATER FROGS (RANA EPEIROTICA, R. BALCANICA) IN THE IONIAN ZONE OF GREECE

ABSTRACT Natural hybrids of Rana epeirotica and Rana balcanica were studied by means of vertical acrylamide electrophoresis to confirm the various types of hybrids distinguished by the bioacoustic method. On the basis of four diagnostic loci (Ldh-1, Mdh-1, a muscle protein, and plasma albumin) at least three types of hybrids are distinguished. The most common type is the typical intermediate hybrid, which at all four loci displayed the two alleles of the parent species in the form of typical heterozygosity. Other types of hybrids give evidence of triploidy with either two genomes of R. balcanica and one of R. epeirotica, or one genome of R. balcanica and two of R. epeirotica. The possible role of the hybrid types is discussed.

Pricing and Hedging of Coco's

Contingent convertible bonds are typical hybrid products in that they are exposed to different types of risk: interest rate risk, equity risk and conversion risk. We first develop a general framework for their pricing and hedging that can be specified in different ways. Then we focus on intensity-based and first-passage time models driven by a finite-dimensional Markov process. The two approaches are qualitatively different. But both allow to price contingent convertibles and calculate dynamic hedging strategies with holdings in related instruments such as fixed income products, the issuing company's stock and credit default swaps. As case studies we consider contingent convertibles issued by Lloyds Banking Group in December of 2009 and Rabobank in March of 2010.

Reducing assembly complexity of microbial genomes with single-molecule sequencing

BackgroundThe short reads output by first- and second-generation DNA sequencing instruments cannot completely reconstruct microbial chromosomes. Therefore, most genomes have been left unfinished due to the significant resources required to manually close gaps in draft assemblies. Third-generation, single-molecule sequencing addresses this problem by greatly increasing sequencing read length, which simplifies the assembly problem.ResultsTo measure the benefit of single-molecule sequencing on microbial genome assembly, we sequenced and assembled the genomes of six bacteria and analyzed the repeat complexity of 2,267 complete bacteria and archaea. Our results indicate that the majority of known bacterial and archaeal genomes can be assembled without gaps, at finished-grade quality, using a single PacBio RS sequencing library. These single-library assemblies are also more accurate than typical short-read assemblies and hybrid assemblies of short and long reads.ConclusionsAutomated assembly of long, single-molecule sequencing data reduces the cost of microbial finishing to $1,000 for most genomes, and future advances in this technology are expected to drive the cost lower. This is expected to increase the number of completed genomes, improve the quality of microbial genome databases, and enable high-fidelity, population-scale studies of pan-genomes and chromosomal organization.

Synthesis and Characterization of Hexagonal Boron Nitride Nanosheets

In this article, hexagonal boron nitride nanosheets have been successfully synthesized by the method of solid-phase sintering using boron oxide (B2O3) and sodium azides (NaN3) as the reactants and magnesium powder as catalyst at 450 °C. Results from XRD suggest that the synthesized products be indexed as pure h-BN. The surface morphology of the products was observed by the scanning electron microscope, that the products are constituted of a large number of the structure of nanosheets. And the SEM images show the sheetlike materials with a diameter of about 500-900 nm, and the thickness is about 100 nm. The far-infrared absorption spectrum showed that the typical sp2 hybrid structure of hexagonal boron nitride. The optical properties of the product are observed in the PL spectra, which shows that the prepared BN emits strong visible luminescence at 445 nm (λex = 325 nm).

A Hybrid Predictive Control Strategy for the Coordinated Voltage

The substation is one of the most important nodes for the power system voltage control. Its dynamic behavior is usually characterized by the interaction of dynamic load models, describing continues variables governed by differential equations, and of discrete controllers and coordinated logic, describing symbolic variables governed by discrete behaviors, logic rules and switching mechanisms. Therefore, the operation and control of the substation is a typical hybrid dynamic system. To make an effective voltage coordinated control in substation, this paper proposed a hybrid predictive control strategy. First, the discrete-time hybrid automata model was given for describing the hybrid voltage control system in substation. Then, by using the voltage-security control constrain instead of the goal of voltage-security control, the voltage coordinated control problem can be converted to a minimization cost problem on the premise of the voltage-security control, based on the technology of the MPC. And, for the discrete control characteristics and different control delays of multi-controllers, a branch and search algorithm was designed to solve the hybrid predictive control problem. This proposed algorithm is suitable for the voltage predictive control of substation, which have less control variables and different controllers’ delays. Finally, the coordinated controller was designed on Dymola. And the example of BPA test system three generations and ten buses included was given for simulation analysis and the verification by the proposed approach for substation coordinated voltage control. The results of simulation showed that the proposed control strategy in the paper is feasible.

Assessment and Mitigation of Interaction Dynamics in Hybrid AC/DC Distribution Generation Systems

Hybrid ac/dc power networks are recently emerged in distribution generation (DG) systems with widespread acceptance under the smart grids environment. However, system-level dynamic interactions might be yielded due to the active control nature and tight regulation of power converters to meet load/generation requirements. This paper presents an assessment and mitigation strategies of such interactions in hybrid networks. A typical and comprehensive hybrid network composed of a DG power park, dc microgrid, islanded ac microgrid interfaced by voltage-source converter (VSC), and a grid-connected VSC is considered. Mathematical modeling and analysis of the input/output admittances of these entities are provided to evaluate the overall system stability based on the Nyquist admittance ratio criterion. It can be shown that the tight regulation of VSCs introduces incremental negative admittances reflected to the common dc link which significantly degrades the system stability. Therefore, active compensators are proposed to actively reshape the input dc-side admittance of the VSCs so that the Nyquist criterion is satisfied. Time- domain -large signal model of a typical hybrid network is implemented to validate the analytical results.

An equity–interest rate hybrid model with stochastic volatility and the interest rate smile

We define an equity-interest rate hybrid model in which the equity part is driven by the Heston stochastic volatility [Hes93], and the interest rate (IR) is generated by the displaced-diffusion stochastic volatility Libor Market Model [AA02]. We assume a non-zero correlation between the main processes. By an appropriate change of measure the dimension of the corresponding pricing PDE can be greatly reduced. We place by a number of approximations the model in the class of affine processes [DPS00], for which we then provide the corresponding forward characteristic function. We discuss in detail the accuracy of the approximations and the efficient calibration. Finally, by experiments, we show the effect of the correlations and interest rate smile/skew on typical equity-interest rate hybrid product prices. For a whole strip of strikes this approximate hybrid model can be evaluated for equity plain vanilla options in just milliseconds.

Analysis of thermal and electrical performance of a hybrid (PV/T) air based solar collector for Iraq

The electrical and thermal performance of a typical single pass hybrid photovoltaic/thermal (PV/T) air collector is modeled, simulated and analyzed for two selected case studies in Iraq. An improved mathematical thermo-electrical model is derived in terms of design, operating and climatic parameters of the hybrid solar collector to evaluate its important characteristics: collector flow and heat removal factors, PV maximum power point and its temperature coefficient, and overall power and efficiency. Unlike previous PV/T thermal models, the present model is obtained with some additions and corrections in radiation and convection heat coefficients for the top loss and for the air duct with more applicable sky temperature correlation. The well-known 5-parameter electrical model of PV module is solved using improved boundary conditions and translation equations for better convergence and accuracy. The voltage temperature coefficient of the PV module is included in the boundary conditions for convergence stability. The module parameters are taken to be dependent on solar radiation and PV cell temperature for improved accuracy. A Matlab computer simulation program is developed to solve the thermo-electrical model. The developed model is verified with previously published experimental results and theoretical simulations; it is proved to be most accurate in respect to percentage errors and correlation coefficients. Different parameters of the PV/T collector such as cell and air temperatures, thermal gain, PV current and voltage, and fill factor have been investigated. The results identified the effects of most important operating conditions such as sky, inlet and cell temperatures, air flow rate and incident solar radiation on the performance of the hybrid collector. The approved model is applied for a winter day (22 January 2011) in Baghdad city and for a summer day (20 May 2011) in Fallujah city. It is found that the electrical, thermal and overall collector efficiencies for the two case studies were 12.3%, 19.4% and 53.6% respectively for the winter day, while that for the summer day were 9%, 22.8% and 47.8%.

One-Pot and Template-Free Fabrication of ZnS·(ethylenediamine)0.5 Hybrid Nanobelts

A template-free and one-pot solvothermal process has been developed for the facile synthesis of ZnS·(en)0.5 (en = ethylenediamine) hybrid nanobelts having diverse length-to-width (aspect) ratios. While typical hybrid nanobelts synthesized at 180 °C for 6 h have an average width of 130 nm, a mean thickness of 55 nm, and an average length of 16 μm, their aspect ratios have been varied by adjusting solvent volume ratios of hydrazine monohydrate (hm) to en. A sufficient amount of sulfide from the reduction of sulfur by hm has been found to be essential for the efficient anisotropic one-dimensional growth of highly crystalline ZnS·(en)0.5 hybrid nanobelts. The photoluminescence spectra of ZnS·(en)0.5 hybrid nanostructures exhibit three bands located at 327, 415–430, and 587–654 nm, which are assigned to band-edge emission, trap sites-related emission, and anion-vacancy emission, respectively. The mean lifetime of photoluminescence having three decay components of 30, 170, and 2700 ps decreases with the volume ratio of hm to en due to the decrease of defect sites with the increase of the aspect ratios of ZnS·(en)0.5 hybrid nanobelts. Compared with bare-ZnS nanobelts prepared by the hydrothermal treatment of ZnS·(en)0.5 hybrid nanobelts, hybrid ones have shown enhanced optical properties that would give them potential for optoelectronic devices.

Hybrid RANS–LES Modeling for Unsteady Cavitating Flow Simulation

A typical hybrid RANS-LES approach, DES (Detached Eddy Simulation), was introduced into cavitating flow simulation in this paper. The applicability of two DES models, including one equation DES model and SST k-ω DES model, and standard k-ε model was analyzed through experimental data of a water tunnel experiment. Validation results illustrate that the precision of DES method depends on the RANS model used and the length scale used to distinguish LES zone and RANS zone. The SST k-ω DES method can well predict cavitating flow. The averaged results gained through this model are better than those of standard k-ε or one equation DES model. By comparison, the one equation DES model shows little advantage than standard k-ε model to simulate cavitating flow.

Non-linear model-based optimization of actuator trajectories for tokamak plasma profile control

A computational method is presented to determine the tokamak actuator time evolution (trajectories) required to optimally reach a given point in the tokamak operating space while satisfying a set of constraints. Usually, trajectories of plasma auxiliary heating, current drive and plasma current required during the transient phases of a tokamak shot to reach a desired shape of the plasma temperature and safety factor (q) profiles are determined by trial-and-error by physics operators. In this paper, these trajectories are calculated by solving a non-linear, constrained, finite-time optimal control problem.The optimization problem contains a physics model of the non-linear plasma profile dynamics, a cost function to be minimized, and a set of constraints on the actuators and plasma quantities. The method is tested by optimizing the trajectories of Ip, heating and current drive power to obtain a typical hybrid plasma q profile at the end of the current ramp-up phase, while minimizing both the Ohmic flux swing and the distance from a stationary condition, and requiring q > 1 and edge Vloop > 0 at all times. The optimized trajectories feature an Ip overshoot similar to that used in existing experiments, and are shown to perform significantly better than a set of non-optimized trajectories, allowing stationary profiles to be obtained at the beginning of the flat-top phase. Additional information is obtained, including the parameter sensitivity of the optimal solution, a linear model describing the linearized dynamics of the profiles around the optimal trajectory, as well as a classification of the actuator trajectories based on the critical constraint which limits their value at a given time. This provides a solid basis for subsequent closed-loop feedback controller design. The tools presented in this paper could be useful to improve existing tokamak operational scenarios, to prepare operation of future machines and optimize their design.

Free-standing Ni-microfiber-supported carbon nanotube aerogel hybrid electrodes in 3D for high-performance supercapacitors

Macroscopic Ni-microfiber-supported carbon nanotube aerogels (CNAGs) have been developed and demonstrate great potential as supercapacitor electrodes. The macroscopic carbon nanotubes (CNTs) are controllably prepared by a catalytic chemical vapour deposition method through CNT growth on a sinter-locked microfibrous structure (SMF) consisting of 5 vol% 8 μm Ni fibers. Polyimide is coated onto the CNTs rooted on the SMF-Ni by an impregnation/polymerization method and is subsequently carbonized by pyrolysis to create self-supporting CNAGs/SMF-Ni composite electrodes, wherein the Ni-fiber network serves as current collector and the CNTs grown on the Ni fiber act as nano conducting wires to link the charge-storage carbon aerogel (CAG) particles. This novel approach permits desirable large-area fabrication and provides a unique combination of high CNAG-loading (up to 71.0 wt%; CAG/CNT: 1.44 wt/wt), binder-free feature, excellent electrical conductivity, large surface area, macro-/meso-/micro-sized hierarchical porous structure and high permeability. A typical hybrid consisting of 68.5 wt% CNAG (CAG/CNT: 1.17 wt/wt) delivers not only a good capacitance (e.g., 359 F per gram CAG) at high rates but also excellent long-cycle life (5% loss after 300 cyclic voltammogram cycles and then almost unchanged through 1000 cycles).

Integrated design and optimization of a complex nonlinear hybrid electric powertrain including simulations in time domain

AbstractThis paper deals with the design and optimization of hybrid electric powertrains. Therefore basic relations of the behavior of hybrid electric powertrain systems and the controller design are introduced. Based on models of typical hybrid electric system components principal optimization approaches with respect to performance parameters like efficiency, availability, lifetime, etc. are shown. Hereby an optimization algorithm based on a global optimization technique is applied. Using the example of a fuel cell based hybrid electric powertrain system the approaches are introduced and compared to each using time‐domain simulations integrated in optimization algorithms. The results show that both approaches are appropriate to design the system as well as the controllers. (© 2011 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)