Evaluation of the Arctic Sea-Ice Simulation on SODA3 Datasets

This study evaluates the Arctic sea-ice simulation of the SODA3 dataset driven by different atmospheric forcing fields and explores the errors of the Arctic sea-ice simulation caused by the forcing field.We find that the SODA3 data driven by different forcing fields represent a significant systematical error in the simulation of Arctic sea-ice concentration,showing a low concentration of thick ice and a high concentration of thin ice.In terms of sea-ice extent,the SODA3 data from different versions well characterize the interannual variability and declining trend in the observed data,but they overestimate the overall Arctic sea-ice extent,which is related to excessive simulation of ice in the sea-ice margin.Compared to observations,all the chosen SODA3 reanalysis versions driven by different atmospheric forcing generally tend to underestimate the Arctic sea-ice thickness,especially for thick ice in the multi-year sea-ice regions.Inaccurate simulations of Arctic sea-ice transport may partly explain the error in SODA3 sea-ice thickness in multi-year sea-ice areas.The results of different SDOA3 versions differ greatly in the Beaufort Sea,the Fram Strait,and the Central Arctic Sea.The difference in sea-ice thickness among different SODA3 versions is primarily due to the thermodynamic contribution,which may come from the diversity of atmospheric forcing fields.Our work provides a reference for using SODA3 data to study Arctic sea ice.

Numerical simulation of drop weight impact sensitivity evaluation criteria for pressed PBXs

A thorough understanding of drop-weight impacted responses for polymer-bonded explosives(PBXs)is significant to evaluate their impact sensitivity.The characteristics of the drop-weight impacted pressed PBXs including deforming,fracturing,forming a local high-temperature region and igniting,were simulated using a coupled mechanical-thermo-chemical model integrating micro-defects evolution.A novel evaluation method for impact sensitivity is established using the relation between the input kinetic energy and the output energy due to deformation,crushing energy,local hot spot energy and ignition.The effects of impact velocity on sensitivity were analyzed and the critical local ignition impact velocity is determined as 4.0-4.5 m/s.The simulated results show that shear-crack friction heating is the dominant ignition mechanism.The region along the boundary of PBXs sample is the most hazardous regions where ignition first occur.The propagation of stress wave in PBXs causes shear-crack hotspot and bulk temperature exhibiting an approximate 45°direction evolution path,which is the main reason that dominated damage-ignition region transits from the boundary to the central of sample.

Evaluation and scenario simulation for forest ecological security in China

Continuously growing populations and rapid economic development have led to the excessive use of forest resources,and the forest ecosystem is threatened.In response,forest ecological security(FES)has attracted attention.In this study,an integrated dynamic simulation model was constructed using the system dynamic method,and it was used to evaluate the FES in China from 1999 to 2014.A scenario analysis was then used to evaluate the changes in the FES under five forestry policy scenarios for the 2015–2050 period,including the baseline,afforestation policy,harvesting policies,management policy,investment policy,and a policy mix.The results showed that the evaluation values of the FES increased during the period from 1999 to 2002,the period from 2004 to 2010 and the year 2014,and they decreased in 2003 and during the period from 2011 to 2013.During the 2015–2050 simulation period,the FES improved continuously.In particular,China would enter a new stage when the economic systems,social systems and ecosystems were in harmony after 2040.To improve the FES and the current status of the FES,a scenario analysis showed the most suitable scenario to be Scenario 5 from 2015 to 2020 and Scenario 2 from 2021 to 2050.To relieve pressure,the most suitable scenario would be Scenario 5 from 2015 to 2040 and from 2046 to 2050,and the most suitable scenario would be Scenario 4 for 2041–2045.A policy mix(Scenario 5)would be most efficient under current conditions,while the effects of all the benefits of the forestry policies would weaken over the long term.The integrated method can be regarded as a decision support tool to help policy makers understand FES and promulgate a reasonable forestry policy.

Simulation Evaluation Study of System Reliability Based on Improved BayesBootstrap Method

For the disadvantages of analyzing system reliability using common Bayes method,an evaluation method based on improved Bayes-Bootstrap method is presented.Firstly,the data obliteration problem existing in traditional Bayes method is analyzed,then an improved sampling arithmetic is proposed on the foundation of an experience function.Finally,effectiveness of this method is proved by an example.The simulating result shows that this method is more accurate than common Bayes method.

Probability estimation based on grey system theory for simulation evaluation

In the evaluation of some simulation systems, only small samples data are gotten due to the limited conditions. In allusion to the evaluation problem of small sample data, an interval estimation approach with the improved grey confidence degree is proposed.On the basis of the definition of grey distance, three kinds of definition of the grey weight for every sample element in grey estimated value are put forward, and then the improved grey confidence degree is designed. In accordance with the new concept, the grey interval estimation for small sample data is deduced. Furthermore,the bootstrap method is applied for more accurate grey confidence interval. Through resampling of the bootstrap, numerous small samples with the corresponding confidence intervals can be obtained. Then the final confidence interval is calculated from the union of these grey confidence intervals. In the end, the simulation system evaluation using the proposed method is conducted. The simulation results show that the reasonable confidence interval is acquired, which demonstrates the feasibility and effectiveness of the proposed method.

Numerical Simulation Analysis and Ecological Evaluation on Wind Environment of Dwelling Groups in Severe Cold Regions

The wind environment around residential building groups is increasingly concerned,while the dwelling groups as the elementary unit of planning design,its quality of surrounding wind environment will directly affect people's life. This study based on the climatic conditions of severe cold regions,selects four dwellings groups with different openings scale and position as the research objects,and then simulates and analyzes the wind speed distribution characteristics of each pattern. Meanwhile,it extracts the wind speed values of one hundred points of each pattern and applies the coefficient of uniformity method to the ecological evaluation. It has been found that grouping pattern of buildings has a dramatic effect on the resulting airflow behavior. Configurations that contain a T-shaped central space with small opened side can effectively prevent and contain airflow in the site offer. The interactive influence between layout of dwelling groups and wind environment are explored,so as to provide basis for the planning design of dwelling groups.

Comparison of delay compensation methods for real-time hybrid simulation using frequency-domain evaluation index

The delay compensation method plays an essential role in maintaining the stability and achieving accurate real-time hybrid simulation results. The effectiveness of various compensation methods in different test scenarios, however, needs to be quantitatively evaluated. In this study, four compensation methods （i.e., the polynomial extrapolation, the linear acceleration extrapolation, the inverse compensation and the adaptive inverse compensation） are selected and compared experimentally using a frequency evaluation index （FEI） method. The effectiveness of the FEI method is first verified through comparison with the discrete transfer fimction approach for compensation methods assuming constant delay. Incomparable advantage is further demonstrated for the FEI method when applied to adaptive compensation methods, where the discrete transfer function approach is difficult to implement. Both numerical simulation and laboratory tests with predefined displacements are conducted using sinusoidal signals and random signals as inputs. Findings from numerical simulation and experimental results demonstrate that the FEI method is an efficient and effective approach to compare the performance of different compensation methods, especially for those requiring adaptation of compensation parameters.

A Sound Quality Objective Evaluation Method Based on Auditory Peripheral Simulation Model

Based on auditory peripheral simulation model, a new Sound Quality Objective Evaluation (SQOE) method is presented,which can be used to model and analyze the impacts of head, shoulder and other parts of human body on sound wave trans-mission.This method employs the artificial head technique, in which the head related transfer function was taken into account tothe outer ear simulation phase.First, a bionic artificial head was designed as the outer ear model with considering the outersound field in view of theory and physical explanations.Then the auditory peripheral simulation model was built, which mimicsthe physiological functions of the human hearing, simulating the acoustic signal transfer process and conversion mechanismsfrom the free field to the peripheral auditory system.Finally, performance comparison was made between the proposed SQOEmethod and ArtemiS software, and the verifications of subjective and objective related analysis were made.Results show thatthe proposed method was economical, simple, and with good evaluation quality.

Urban Development Boundary Simulation Based on“Double Evaluation”and FLUS Model

The delimitation of urban development boundaries plays an important role in optimizing the nation land space.“Double evaluation”is one of the important means to study and predict the scale of new construction land in the future and to determine the spatial distribution of urban construction land.This study combines the“double evaluation”with the FLUS(Future Land-Use Simulation)model to study the delimitation of the urban development boundary of Yichang.The results show that:(1)the“double evaluation”method comprehensively considers the carrying capacity of the resource environmental bear and the suitability of urban development;(2)the FLUS model can better couple the“double evaluation”method for Land Use/Land Cover(LULC)suitability evaluation,Land Use/land Cover Change(LUCC)simulation and urban development boundary delineation,and the overall accuracy of the simulation reaches 96%;(3)according to the requirements of relevant national policies,this study divides the urban development boundary of the study area into concentrated construction areas,elastic development areas and special purpose areas.This function-based division can meet the requirements of urban flexible development,ecological protection and urban safety.This research combines the FLUS model,which is widely used in the simulation of LUCC,with the double evaluation method used in China’s new round of land and space planning to obtain the result of the urban development boundary.This result is consistent with the existing plan of the study area.

Design of Simulation System for Effectiveness Evaluation of Future Airspace Window Shooting

Future Airspace Window Shooting is a newly developed technology, which needs effectiveness evaluation before widely used. Future airspace window shooting technology, simulation system development principles and software chosen to develop the simulation system are introduced in the first. And then the overall design of the system, realization of the system and effectiveness evaluation through simulation are discussed in detail. Through the simulation, it is known that the FAW shooting has more superior performance when facing maneuvering targets.

An Efficient Simulation Tool of Performance Evaluation for Communication Networks

We provide an efficient simulation tool for performance evaluation in communication networks. Not only the general simulation functions-which can be found in some old simulation tools, but also the perturbation function module via the Standard Clock (SC) approach-in which more than 2 perturbation simulation event paths can be constructed parallelly based on a single nominal simulation event path is included in this simulation software platform.

Reliability Evaluation of Distribution Systems under <i>μ</i>Grid-Tied and Islanded <i>μ</i>Grid Modes Using Monte Carlo Simulation

Reliability evaluation of distribution networks under grid-tied and islanded μ grid modes is presented. The Monte Carlo simulation (MCS) algorithm is applied to a modified RBTS Bus 2 distribution network. The network includes three types of distributed energy resources, namely, solar photovoltaic (PV), wind turbine (WT), and diesel turbine generator (DTG). These distributed generators contribute to supply part of the load during grid-connected mode, but supply 100% of the load in the islanded μ grid mode. A storage system is included to decrease the peak load since the peak of the output power of the PV’s and the peak load do not match time wise in most load profiles. The impact of implementing renewable distributed generation, storage systems, and conventional generation on the reliability of distribution network is studied. This study shows that the penetration of distributed generations can improve the reliability indices of the distribution network.

Surgical simulation and evaluation in anterior cruciate ligament reconstruction with image-free navigation

A surgical simulation and evaluation method in the anterior cruciate ligament(ACL)reconstructionwith image-free navigation was presented.Firstly,video tracking module,bone surface reconstructionmodule and virtual simulation module of this system were discussed.Secondly,the coordinate relations ofseveral surgery objects(including surgical instrument,anatomical,camera and screen)in the surgicalenvironment,the tracking based on MicronTracker with two cameras and the bone surface real-time recon-struction based on the Delaunay algorithm were introduced in detail.Finally,experiments of anisometrymeasurement and virtual simulation on two plastics were carried out to verify the validity of the proposedmethod.The anisometry value of reconstructed ACL was 8.970039mm.The effectiveness of ACL recon-struction has been proved by preliminary evaluation trials.

Dependability Evaluation of a Vehicle System by Simulation Method

The vehicle system studied in this paper is a type of complex repairable system in which the subsystems follow various failure distributions and conform to arbitrary failure and repair distributions.The failure data of subsystems are sometimes lacking,and the reliability test sample sizes tend to be small.Monte-Carlo technique combined with Bayes method is used to evaluate its dependability(reliability and maintainability).Following the "first-in,first-out" queuing rule,the logic relation of dependability is established by means of repairing priority and event lists.Simulation outputs the entire history of a mission,statistics of reliability and maintainability parameters and provides the basic data for system reliability design and maintainability management.

The Warm Arctic-Cold Eurasia Pattern and Its Key Region in Winter in CMIP6 Model Simulations

An enhanced Warm Arctic-Cold Eurasia(WACE)pattern has been a notable feature in recent winters of the Northern Hemisphere.However,divergent results between model and observational studies of the WACE still remain.This study evaluates the performance of 39 climate models participating in the Coupled Model Intercomparison Project Phase 6(CMIP6)in simulating the WACE pattern in winter of 1980-2014 and explores the key factors causing the differences in the simulation capability among the models.The results show that the multimodel ensemble(MME)can better simulate the spatial distribution of the WACE pattern than most single models.Models that can/cannot simulate both the climatology and the standard deviation of the Eurasian winter surface air temperature well,especially the latter,usually can/cannot simulate the WACE pattern well.This mainly results from the different abilities of the models to simulate the range and intensity of the warm anomaly in the Barents Sea-Kara seas(BKS)region.Further analysis shows that a good performance of the models in the BKS area is usually related to their ability to simulate location and persistence of Ural blocking(UB),which can transport heat to the BKS region,causing the warm Arctic,and strengthen the westerly trough downstream,cooling central Eurasia.Therefore,simulation of UB is key and significantly affects the model’s performance in simulating the WACE.

Evaluation of Arctic Sea-ice Cover and Thickness Simulated by MITgcm

A regional Arctic Ocean configuration of the Massachusetts Institute of Technology General Circulation Model(MITgcm)is applied to simulate the Arctic sea ice from 1991 to 2012.The simulations are evaluated by comparing them with observations from different sources.The results show that MITgcm can reproduce the interannual and seasonal variability of the sea-ice extent,but underestimates the trend in sea-ice extent,especially in September.The ice concentration and thickness distributions are comparable to those from the observations,with most deviations within the observational uncertainties and less than 0.5 m,respectively.The simulated sea-ice extents are better correlated with observations in September,with a correlation coefficient of 0.95,than in March,with a correlation coefficient of 0.83.However,the distributions of sea-ice concentration are better simulated in March,with higher pattern correlation coefficients(0.98)than in September.When the model underestimates the atmospheric influence on the sea-ice evolution in March,deviations in the sea-ice concentration arise at the ice edges and are higher than those in September.In contrast,when the model underestimates the oceanic boundaries’influence on the September sea-ice evolution,disagreements in the distribution of the sea-ice concentration and its trend are found over most marginal seas in the Arctic Ocean.The uncertainties of the model,whereby it fails to incorporate the atmospheric information in March and oceanic information in September,contribute to varying model errors with the seasons.

Numerical simulation and response analysis of microspherical focused logging in inclined micro-fractured formation

Tight and unconventional reservoirs have become the focus with the progress of petroleum exploration and development.Micro-fractures in these reservoirs can effectively improve reservoir permeability,and well-developed micro-fractures can serve to directly improve productivity.Compared with the centered electrical well logging method,the Micro Spherical Focused Logging(MSFL)is more suitable for microfracture identification due to its high resolution and near borehole wall measuring method.In this study,an anisotropic model is used to depict micro-fractured formation.First,a forward model with microfractured formation,borehole,logging instrument and surrounding rock is established.Subsequently,MSFL responses under different micro-fracture porosity,resistivity,dip angle and borehole radius,are calculated based on the finite element method(FEM).Finally,the MSFL responses under different microfracture parameters are analyzed with the response laws clarified.

MAIN FUNCTIONS AND EVALUATION OF CUTI'S COMPLEX——Simulated Saturation Diving Chamber

The 300 msw Simulated Saturation Diving Chamber Complex was designed and built by ourselves. It was completed at the end of 1985. A 300 msw trimixed saturation diving experiment was successfully conducted in the complex by Chinese Underwater Technology Institute(CUTI) from May 22 to June 12 of 1987. During the experiment, 4 divers habitated in the complex for 20 days, and they performed 16 person-time excursion dives and 8 other tests. The result of the experiment indicates that the complex is well designed, suitably configurated, wholly integrated and steadily run, as well as of low leakage. The main functions of the complex have approached to those of the same kind in the world. The complex can be used as a basic facility for serving the nation's saturation diving technology, underwater operation, personnel training, etc.

Evaluation and selection of the ship collaborative design resources based on AHP and genetic and simulated annealing algorithm

The characteristics of the design resources in the ship collaborative design is described and the hierarchical model for the evaluation of the design resources is established. The comprehensive evaluation of the co-designers for the collaborative design resources has been done from different aspects using Analytic Hierarchy Process (AHP),and according to the evaluation results,the candidates are determined. Meanwhile,based on the principle of minimum cost,and starting from the relations between the design tasks and the corresponding co-designers,the optimizing selection model of the collaborators is established and one novel genetic combined with simulated annealing algorithm is proposed to realize the optimization. It overcomes the defects of the genetic algorithm which may lead to the premature convergence and local optimization if used individually. Through the application of this method in the ship collaborative design system,it proves the feasibility and provides a quantitative method for the optimizing selection of the design resources.