Halin图和Series-Parallel图的动态色数

图的动态着色是BruceMontgomery于2001年引入的一个新概念。本文分别证明了Halin图和非5圈的Series Parallel图的动态色数都不超过4。

Selective maintenance problem for series–parallel system under economic dependence

In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formulated in a simple and consistent manner. Selective maintenance problem under economic dependence(EDSMP) is presented based on a series–parallel system in this paper. A case study shows that the system reliability is promoted to a certain extent, which can validate the validity of the EDSMP model. The influence of the ratio of set-up cost on system performance is mainly discussed under different economic dependences. Several existing improvements of classical exhaust algorithm are further modified to solve a large sized EDSMP rapidly. Experimental results illustrate that these improvements can reduce CPU time significantly.Furthermore the contribution of each improvement is defined here, and then their contributions are compared thoroughly.

Performance evaluation of series and parallel strategies for financial time series forecasting

Background:Improving financial time series forecasting is one of the most challenging and vital issues facing numerous financial analysts and decision makers.Given its direct impact on related decisions,various attempts have been made to achieve more accurate and reliable forecasting results,of which the combining of individual models remains a widely applied approach.In general,individual models are combined under two main strategies:series and parallel.While it has been proven that these strategies can improve overall forecasting accuracy,the literature on time series forecasting remains vague on the choice of an appropriate strategy to generate a more accurate hybrid model.Methods:Therefore,this study’s key aim is to evaluate the performance of series and parallel strategies to determine a more accurate one.Results:Accordingly,the predictive capabilities of five hybrid models are constructed on the basis of series and parallel strategies compared with each other and with their base models to forecast stock price.To do so,autoregressive integrated moving average(ARIMA)and multilayer perceptrons(MLPs)are used to construct two series hybrid models,ARIMA-MLP and MLP-ARIMA,and three parallel hybrid models,simple average,linear regression,and genetic algorithm models.Conclusion:The empirical forecasting results for two benchmark datasets,that is,the closing of the Shenzhen Integrated Index(SZII)and that of Standard and Poor’s 500(S&P 500),indicate that although all hybrid models perform better than at least one of their individual components,the series combination strategy produces more accurate hybrid models for financial time series forecasting.

A Novel Parallel Scheme for Fast Similarity Search in Large Time Series

The similarity search is one of the fundamental components in time series data mining,e.g.clustering,classification,association rules mining.Many methods have been proposed to measure the similarity between time series,including Euclidean distance,Manhattan distance,and dynamic time warping(DTW).In contrast,DTW has been suggested to allow more robust similarity measure and be able to find the optimal alignment in time series.However,due to its quadratic time and space complexity,DTW is not suitable for large time series datasets.Many improving algorithms have been proposed for DTW search in large databases,such as approximate search or exact indexed search.Unlike the previous modified algorithm,this paper presents a novel parallel scheme for fast similarity search based on DTW,which is called MRDTW(MapRedcuebased DTW).The experimental results show that our approach not only retained the original accuracy as DTW,but also greatly improved the efficiency of similarity measure in large time series.

Input series out putparallel based multi-modular boost half bridge DC-DC converter with a dynamic control scheme

Multi-modular system plays an important role in power system architecture because low voltage and low power converters can be connected in any combination parallel or series at input/ output side in order to obtained any given power system specifications. Multi-modular boost haft bridge DC-DC converter in the configuration of input series output parallel has been investigated in this paper. The boost half bridge DC-DC converters are connected in input series output parallel con- figuration in order to achieve equal input voltage sharing and output current sharing between the con- verters. This can be achieved with the help of dynamic control scheme which consists of two loops, a voltage loop and a current loop, for each module. Dynamic behavior of multi-modular converter configuration has been observe by varying the load condition. Moreover, the results obtained through multi-modular converter describe that the system has good dynamic and steady state response. Al- though two converter modules are focused in this paper but it can be modified to any number of modules.

Constitutive equations of 1060 pure aluminum based on modified double multiple nonlinear regression model

In order to study the work-ability and establish the optimum hot formation processing parameters for industrial 1060 pure aluminum, the compressive deformation behavior of pure aluminum was investigated at temperatures of 523?823 K and strain rates of 0.005?10 s?1 on a Gleeble?1500 thermo-simulation machine. The influence rule of processing parameters (strain, strain rate and temperature) on flow stress of pure aluminum was investigated. Nine analysis factors consisting of material parameters and according weights were optimized. Then, the constitutive equations of multilevel series rules, multilevel parallel rules and multilevel series &parallel rules were established. The correlation coefficients (R) are 0.992, 0.988 and 0.990, respectively, and the average absolute relative errors (AAREs) are 6.77%, 8.70% and 7.63%, respectively, which proves that the constitutive equations of multilevel series rules can predict the flow stress of pure aluminum with good correlation and precision.

Modular Reciprocating HVDC Circuit Breaker with Current-limiting and Bi-directional Series-parallel Branch Switching Capability

The high-voltage direct current(HVDC)circuit breaker is becoming popular with the rapid development of the flexible HVDC grid for efficient DC fault ride-through purposes.This paper proposes a novel module for reciprocating HVDC circuit breaker topology,whose branch connections are able to switch between series and parallel modes to limit the rising rate and interrupt the DC fault currents.Diode-bridge submodules(DBSMs)are used to compose the main branch for current interruption.Besides fault clearance,the proposed topology has the advantageous function of DC fault current limiting by employing DBSMs with bi-directional conduction capability.The topology can easily switch among branch connection modes through the assembled trans-valves,and their resistance and reactance are very small in the normal state when branches are in parallel and the values become promptly large in the transient state when the branches are series connected.With the modular design,it is easy to change the number of branches or sub-modules and the types of sub-modules to adapt to more specific needs.A 6-terminal modular multi-level converter(MMC)based HVDC grid is established in PSCAD/EMTDC,and various simulation scenarios are carried out to validate the proposed topology.

“Series and parallel” design of ether linkage and imidazolium cation synergistically regulated four-armed polymerized ionic liquid for all-solid-state polymer electrolyte

Developing all-solid-state polymer electrolytes(SPEs) with high electrochemical performances and stability is of great importance for exploiting of high energy density and safe batteries. Herein, ether linkage and imidazolium ionic liquid(ILs) are incorporated into the multi-armed polymer backbone though the series and parallel way. The parallel polymeric ionic liquid(P-P(PEGMA-IM)) maximizes the synergistic effect of ILs and ether linkage, which endowed the material with low crystallinity and high flame retardancy. The P-P(PEGMA-IM) based P-SPE presents a high ionic conductivity of 0.489 m S/cm at 60°C, an excellent lithium-ion transference number of 0.46 and a wide electrochemical window of 4.87 V.The assembled lithium metal battery using P-SPE can deliver a capacity of 151 m Ah/g at 0.2 C, and the capacity retention ratio reaches 82% with a columbic efficiency beyond 99%. The overpotential of P-SPE based symmetric battery is 0.08 V, and there is no apparent magnifying even after 130 h cycling. This new design provides a new avenue for exploitation of advanced SPEs for the next-generation batteries.

Characteristics of Si-PIN nuclear radiation detectors stacked in series and parallel

The silicon-based diodes coated with a thin film of neutron reactive materials have been shown to produce excellent neutron detectors. We have fabricated the thin-film-coated single Si-PIN neutron detectors and stacked ones coupled in series and parallel in this work. The stacked detectors show the advantage of improving the detection efficiency of neutron detecting, which essentially attributes to the increase of the effective detection area. It is shown that the stacked detector in series has more superior performance than the parallel one. This work provides a feasible method to develop solid-state semiconductor neutron detectors with high neutron detection efficiency and high response speed.

Performance analysis of series/parallel and dual side LCC compensation topologies of inductive power transfer for EV battery charging system

In an inductive battery charging system,for better power transfer capability and attaining required power level,compensation is necessary.This paper analyzes series/parallel(S/P)and dual side inductorcapacitor-capacitor(LCC)compensation topologies for inductive power transfer of electric vehicle(EV)battery charging system.The design and modeling steps of inductive power transfer for electric vehicle battery charging system are presented.Besides,the equivalent electrical circuits are used to describe the circuit compensation topologies.The results convey that the efficiency of dual side LCC compensation is higher than that of S/P compensation at variable mutual inductance(misalignment).

An Explicit Solution for a Series and Parallel Queue with Retrial,Losses,and Bernoulli Schedule

This paper deals with the series and parallel queueing system in which there are two servers whose service time follow two exponential distributions.Each arriving customer either enters into the tandem service with probability or joins the service of the single server with complementary probability.We assume that the customers of arriving at the first server who find the first server is busy join an orbit and retry to enter the server after some time and of arriving at the second server who find the second server is busy are lost.For this model,we obtain the explicit expressions of the joint stationary distribution between the number of customers in the orbit and the states of the servers.

Analysis and Prototyping of Multicellular DC-DC Transformer for Environmentally Friendly Data Centers

A multicellular DCX （dc-dc transformer） using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves as an ideal transformer, and this behavior solves the voltage imbalance issue in the multicellular converter topology. The analysis of the unregulated cell converter is conducted by using the state space averaging method, and the operation condition for the ideal transformer is specified. The behavior of the multicellular DCX using the high speed cell converters has been also analyzed, and the voltage imbalance issue among cell converters is discussed quantitatively. A prototype of a 19.2 kW 384 V-384 V multicellular DCX using sixty-four unregulated cell converters is fabricated and the validity of the analyses is verified.

Hybrid robust fault detection and isolation of satellite reaction wheel actuators

In this paper,a combined robust fault detection and isolation scheme is studied for satellite system subject to actuator faults,external disturbances,and parametric uncertainties.The proposed methodology incorporates a residual generation module,including a bank of filters,into an intelligent residual evaluation module.First,residual filters are designed based on an improved nonlinear differential algebraic approach so that they are not affected by external disturbances.The residual evaluation module is developed based on the suggested series and parallel forms.Further,a new ensemble classification scheme defined as blended learning integrates heterogeneous classifiers to enhance the performance.A wide range of simulations is carried out in a high-fidelity satellite simulator subject to the constant and time-varying actuator faults in the presence of disturbances,manoeuvres,uncertainties,and noises.The obtained results demonstrate the effectiveness of the proposed robust fault detection and isolation method compared to the traditional nonlinear differential algebraic approach.

INVERSE CENTER LOCATION PROBLEM ON A TREE

This paper discusses the inverse center location problem restricted on a tree with different costs and bound constraints. The authors first show that the problem can be formulated as a series of combinatorial linear programs, then an O（｜V｜^2 log ｜V｜） time algorithm to solve the problem is presented. For the equal cost case, the authors further give an O（｜V｜） time algorithm.

A novel monocrystalline PV array configuration for enhancing the maximum power under partial shading conditions

Solar photovoltaic(PV)systems have gained importance as a promising renewable energy source in recent years.PV arrays are prone to variable irradiance levels under partial shading conditions due to non-uniform shading.As a result,there will be a decrease in the amount of power produced and hotspots will occur.To overcome these issues,it is essential to select an appropriate PV material and a suitable array configuration.To obtain the maximum output power from a PV array under partial shading conditions,this paper suggests a novel triple-series–parallel ladder topology with monocrystalline PV material.Considering short and wide,long and wide,short and narrow,long and narrow,middle and diagonal shading situations,a 6×6-sized array has been considered and compared with other existing configurations such as total cross-tied,bridge-link,honeycomb,series–parallel and series–parallel cross-tied.The proposed configuration has an optimal number of cross ties to produce maximum power.It has 4 cross ties fewer than a honeycomb,3 cross ties fewer than a bridge link,16 cross ties fewer than a total cross-tied and 7 cross ties fewer than series–parallel cross-tied configurations.The proposed configuration has an improvement in power of 0.1%to 20%compared with other configurations under the considered shading scenarios.

Electrode pattern design for GaAs betavoltaic batteries

The sensitivities of betavoltaic batteries and photovoltaic batteries to series and parallel resistance are studied.Based on the study,an electrode pattern design principle of GaAs betavoltaic batteries is proposed.GaAs PIN junctions with and without the proposed electrode pattern are fabricated and measured under the illumination of ^（63）Ni.Results show that the proposed electrode can reduce the backscattering and shadowing for the beta particles from ^（63）Ni to increase the GaAs betavoltaic battery short circuit currents effectively but has little impact on the fill factors and ideal factors.