Conceptual Modeling and Simulation Application Analysis of In-service Assessment

Firstly,this paper expounds the conceptual connotation of inservice assessment in the new system,then applies modeling and Simulation in the field of in-service assessment,establishes the conceptual model of inservice assessment and its process,and finally analyzes the application of modeling and simulation in the specific links of in-service assessment.

Multi-scenario Simulation of the Impact of Land Use Change on the Ecosystem Service Value in the Suzhou-Wuxi-Changzhou Metropolitan Area,China

As the most economically developed metropolitan area in China’s Yangtze River Delta,the rapid changing land use patterns of Suzhou-Wuxi-Changzhou(Su-Xi-Chang) metropolitan area have profound impacts on the ecosystem service value(ESV).Based on the patterns of land use change and the ESV change in Su-Xi-Chang metropolitan area from 2000 to 2020,we set up four scenarios:natural development scenario,urban development scenario,arable land protection scenario and ecological protection scenario,and simulated the impact of land use changes on the ESV in these scenarios.The results showed that:1) the area of built-up land in the Su-XiChang metropolitan area increased significantly from 2000 to 2020,and the area of other types of land decreased.Arable land underwent the highest transfer-out area,and was primarily converted into built-up land.The total ESV of Su-Xi-Chang metropolitan area increased initially then declined from 2000–2020,and the value of almost all individual ecosystem services decreased.2) Population density,GDP per area,night lighting intensity,and road network density can negatively impact the ESV.3) The total ESV loss under the natural development and urban development scenarios was high,and the expansion of the built-up land and the drastic shrinkage of the arable land contributed to the ESV decline under both scenarios.The total ESV under arable land protection and ecological protection scenarios increases,and therefore these scenarios are suitable for future land use optimization in Su-Xi-Chang.This study could provide a certain reference for land use planning and allocation,and offer guidance for the rational allocation of land resources.

Spatiotemporal Characteristics and Future Scenario Simulation of the Trade-offs and Synergies of Mountain Ecosystem Services: A Case Study of the Dabie Mountains Area, China

Mountain ecosystems play an essential role in supporting regional sustainable development and improving local ecological environments. However, economic development in mountainous areas has long been lagging, and multiple conflicts related to resource assurance, ecological protection, and economic development have emerged. An accurate grasp of the current status and evolutionary trends of mountain ecosystems is essential to enhance the overall benefits of ecosystem services and maintain regional ecological security. Based on the In VEST(Integrated Valuation of Ecosystem Services and Trade-offs) model, this study analyzed the spatiotemporal evolution patterns and the trade-offs and synergies among ecosystem services(ES) in the Dabie Mountains Area(DMA) of eastern China. The Markov-PLUS(Patch-generating Land Use Simulation) model was used to conduct a multi-scenario simulation of the area's future development. Water yield(WY) and soil conservation(SC) had overall increasing trends during 2000-2020, carbon storage(CS)decreased overall but slowed with time, and habitat quality(HQ) increased and then decreased. The ecological protection scenario is the best scenario for improving ES in the DMA by 2030;compared to 2020, the total WY would decrease by 3.77 × 10^(8) m^(3), SC would increase by 0.65 × 10^(6) t, CS would increase by 1.33 × 10^(6) t, and HQ would increase by 0.06%. The comprehensive development scenario is the second-most effective scenario for ecological improvement, while the natural development scenario did not have a significant effect. However, as the comprehensive development scenario considers both environmental protection and economic development, which are both vital for the sustainable development of the mountainous areas, this scenario is considered the most suitable path for future development. There are trade-offs between WY, CS, and HQ, while there are synergies between SC, CS, and HQ. Spatially, the DMA's central core district is the main strong synergistic area, the marginal zone is the weak synergistic area, and trade-offs are mainly distributed in the transition zone.

Response of ecosystem carbon storage to land use change from 1985 to 2050 in the Ningxia Section of Yellow River Basin,China

Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage(ECS),particularly in ecologically sensitive areas with arid and semi-arid climate.In this study,we calculated the ECS in the Ningxia Section of Yellow River Basin,China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model based on land use data.We further predicted the spatial distribution of ECS in 2050 under four land use scenarios:natural development scenario(NDS),ecological protection scenario(EPS),cultivated land protection scenario(CPS),and urban development scenario(UDS)using the patch-generating land use simulation(PLUS)model,and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector(Geodetector).Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×10^(6) t in 2010,followed by a decreasing trend to 2050.The spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area,and low values in the western and northern parts.Between 1985 and 2020,land use changes occurred mainly through the expansion of cultivated land,woodland,and construction land at the expense of unused land.The total ECS in 2050 under different land use scenarios(ranked as EPS>CPS>NDS>UDS)would be lower than that in 2020.Nighttime light was the largest contributor to the spatial differentiation of ECS,with soil type and annual mean temperature being the major natural driving factors.Findings of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.

Land Use Dynamics and Ecosystem Service Value Changes in the Yangtze River Delta Urban Agglomeration Under Different Scenarios

Urban agglomerations,serving as pivotal centers of human activity,undergo swift alterations in ecosystem services prompted by shifts in land utilization.Strengthening the monitoring of ecosystem services in present and future urban agglomerations contributes to the rational planning of these areas and enhances the well-being of their inhabitants.Here,we analyzed land use conversion in the Yangtze River Delta(YRD)urban agglomeration during 1990-2020 and discussed the spatiotemporal response and main drivers of changes in ecosystem service value(ESV).By considering the different development strategic directions described in land use planning policies,we predicted land use conversion and its impact on ESV using the Future Land Use Simulation(FLUS)model in three scenari-os in 2025 and 2030.Results show that:1)from 1990 to 2020,land use change is mainly manifested as the continuous expansion of con-struction land to cultivated land.Among the reduced cultivated land,82.2%were occupied by construction land.2)The land use types conversion caused a loss of 21.85 billion yuan(RMB)in ESV during 1990-2020.Moreover,the large reduction of cultivated land area led to the continuous decline of food production value,accounting for 13%of the total ESV loss.3)From 2020 to 2030,land use change will mainly focus on Yangzhou and Zhenjiang in central Jiangsu Province and Taizhou in southern Zhejiang Province.Under the BAU(natural development)and ED(cultivated land protection)scenarios,construction land expansion remains dominant.In contrast,under the EP(ecological protection)scenario,the areas of water bodies and forest land increase significantly.Among the different scenarios,ESV is highest in the EP scenario,making it the optimal solution for sustainable land use.It can be seen that the space use conflict among urban,agriculture and ecology is a key factor leading to ESV change in the urban agglomeration of Yangtze River Delta.There-fore,it is crucial to maintain spatial land use coordination.Our findings provide suggestions for scientific and rational land use planning for the urban agglomeration.

Technical Feasibility Study of Passenger Rail Service along the West Route between Las Vegas and Los Angeles

The study evaluates the feasibility of running passenger train service from Las Vegas, NV on the Union Pacific Railroad (UPRR), to Barstow, on the Burlington Northern Santa Fe (BNSF) track, to Mojave on UPRR track again, and to Lancaster connecting Metrolink to their destinations in Southern California. In this study, the railroad infrastructure was inventoried and issues related to running the passenger service were identified. Passenger train operation was evaluated based on the Rail Traffic Controller (RTC) simulation model. The performance measures of passenger trains including travel time, overall delay and average speed are analyzed. The uncertainty in freight flow and its impact on providing the passenger service is addressed by conducting a sensitivity analysis. The conclusion is that the existing railroad infrastructure is sufficient to provide a passenger train service from Las Vegas to Los Angeles. From an operational perspective, the passenger train is not expected to influence freight trains’ performance on the existing railroads. When freight train flows are increased to 50%, the influence of passenger train service on the freight operation is still minimal. This study recommends restoring a platform at the Las Vegas Station. At the Mojave Station, special care should be given on running the passenger trains where there is no direct railroad connection from BNSF to UPRR. Platforms and walkways require construction at the Lancaster Station for transferring passengers between the Metrolink trains and X-Train. Transferring the passenger train at this station involves stopping the train on mainline and coordinating the operations between different railroads.

Multi-scenario Simulation for 2060 and Driving Factors of the Eco-spatial Carbon Sink in the Beibu Gulf Urban Agglomeration, China

Since China announced its goal of becoming carbon-neutral by 2060, carbon neutrality has become a major target in the development of China's urban agglomerations. This study applied the Future Land Use Simulation(FLUS) model to predict the land use pattern of the ecological space of the Beibu Gulf urban agglomeration, in 2060 under ecological priority, agricultural priority and urbanized priority scenarios. The Integrated Valuation of Ecosystem Services and Trade-offs(In VEST) model was employed to analyse the spatial changes in ecological space carbon storage in each scenario from 2020 to 2060. Then, this study used a Geographically Weighted Regression(GWR) model to determine the main driving factors that influence the changes in land carbon sinking capacity. The results of the study can be summarised as follows: firstly, the agricultural and ecological priority scenarios will achieve balanced urban expansion and environmental protection of resources in an ecological space. The urbanized priority scenario will reduce the carbon sinking capacity. Among the simulation scenarios for 2060, carbon storage in the urbanized priority scenario will decrease by 112.26 × 10^(6) t compared with that for 2020 and the average carbon density will decrease by 0.96 kg/m^(2) compared with that for 2020. Carbon storage in the agricultural priority scenario will increase by 84.11 × 10^(6) t, and the average carbon density will decrease by 0.72 kg/m^(2). Carbon storage in the ecological priority scenario will increase by 3.03 × 10^(6) t, and the average carbon density will increase by 0.03 kg/m^(2). Under the premise that the population of the town will increases continuously, the ecological priority development approach may be a wise choice.Secondly, slope, distance to river and elevation are the most important factors that influence the carbon sink pattern of the ecological space in the Beibu Gulf urban agglomeration, followed by GDP, population density, slope direction and distance to traffic infrastructure.At the same time, urban space expansion is the main cause of the changes of this natural factors. Thirdly, the decreasing trend of ecological space is difficult to reverse, so reasonable land use policy to curb the spatial expansion of cities need to be made.

基于HLA／MAS的野营保障仿真建模研究

在分析研究HLA与MAS结构与功能的基础上,提出了一种HLA与MAS的联合仿真建模策略,即以HLA/RTI为主体架构,将仿真模型分为底层Agent对象、中间层MA联邦成员、上层MAS联邦,利用MAS/Agent技术进行对象层智能建模。并将该策略应用于野营保障仿真模型的构建,分析了模型结构与组成,设计了主要仿真流程及Agent通信控制策略,给出了类定义的实例,探讨了原型系统的实现。

基于MAS的复杂网络安全形式化建模

针对网络攻击和防御形式化建模逼真度低和描述不规范的问题,基于多Agent建模思想提出了一种"微-宏"观相结合的具有良好扩展性的形式化建模方法,该方法从微观上描述了个体Agent的静态属性和动态行为,从宏观上描述了角色分配方式和各Agent之间的联系。接着以DDoS攻击与防御为例,给出了上述方法的具体实现过程。最后,仿真验证了DDoS攻防模型的正确性和有效性。

Modeling and simulation as a service architecture for deploying resources in the Cloud

In recent years,Cloud Computing has become popular to facilitate the use of Modeling and Simulation(M&S)resources.Nevertheless,there are still various issues to solve,including the structure constrain of chosen web service frameworks,the sharing of varied resources in the Cloud,and the difficulties in reproducing experiments.We show a new architecture based on Cloud Computing and new modeling methods to deal with these issues.This layered architecture,called Cloud Architecture for Modeling and Simulation as a Service(CAMSaaS),simplifies the deployment of M&S resources as services in the Cloud.CAMSaaS supports hierarchical resource services,experimental frameworks,scalable infrastructure and makes everything as a service.We deploy varied M&S resources as services in the Cloud,and build a Modeling and Simulation as a Service(MSaaS)middleware called CloudRISE to manage a variety of M&S resources.We also use the experimental framework concept to simplify the management of experiment environments.We present a case study for crowd evacuation application using the architecture.

A Control Theoretical Model of Web Service Value Development

This paper describes a control theoretical model of collaborative value development. This model is designed to assist managers in choosing parameters that are critical to the development process in service design and support their Business Model. This methodology uses control system modelling of web-based service value generation implemented in SIMULINK/MATLAB. An application based on public domain Wikipedia data is used to validate and develop the model. A control theoretic model applied to the creation of Wikipedia articles shows very good agreement with Wikipedia published data for the time dependent growth in articles produced, and editors used, well within the variability of parametric data listed publically justifying the principle equations used in the model. This development and fine tuning of the model has been limited by the publically available data. To obtain a more accurate model in this area would need the co-operation of web service organisations to reveal confidential data. This modelling procedure can produce a decision support process for service design and could, with modification be applied much more widely to other choices in service design/implementation, even allowing for user contribution to be evaluated. This work shows how subjective judgements on value and other intangibles need to be continually re-evaluated. Such methodology has not been applied elsewhere to value generation applications. It could be used to rank contributions from co-creators for reward sharing.

基于SAAS的LVC装备试验资源实时调度模型研究

真实虚拟构造仿真为装备体系试验提供了有效技术手段。针对试验中大量异构仿真资源对象间的交互难以满足试验任务实时性需求问题,开展仿真资源实时调度模型研究。分析模型的功能组成,将调度模型划分为远程方法通信实现、远程方法云服务、优化调度策略3个子模型,分析各子模型的功能及其之间的关系,给出模型运行的步骤以及实现原理,并构建标准实验环境,验证模型算法。实验表明,在模型时延要求小于1 ms的标准测试环境下,云服务环境最多可承载大约30个节点同时提出订阅需求,并且调度成功率均大于98.5%,丢包率为0,符合模型性能要求。

MDA与先进分布仿真技术

针对仿真系统的互操作和可重用问题,介绍了OMG提出的MDA技术,在此基础上,探讨了MDA的技术、思想与HLA技术相结合的可能,并给出了建立MDA与HLA融合的技术途径,最后,基于MDA和Web技术,介绍了美军提出的新一代建模与仿真框架XMSF。

基于SOA的仿真服务系统

分布式仿真技术的发展离不开Web技术的推动,当前也只有与Web兼容才能满足不同领域仿真应用的需求。当前Web领域正经历着深刻的变化,新标准和新技术不断出现,如何将Web领域的最新成果集成应用到建模与仿真系统中以弥补现有仿真技术的不足及提高仿真系统的能力是目前仿真技术发展面临的主要问题。Web服务技术是当今IT业的新兴力量,Web服务技术的成熟使面向服务的架构在企业级应用集成中得到了广泛应用。在详细介绍SOA及其实现技术Web服务的基础上,结合分布式仿真的特点提出了基于SOA的仿真服务系统的概念,为建立基于Web的建模与仿真系统给出了一种解决方案。

基于SOA的云计算流域模拟模型集成架构的研究

针对现有流域模型集成系统接口不统一,系统与模型之间集成困难,缺乏通用性和可扩展性等问题,采用SOA与云计算技术,构建了一个开放的、可扩展的、可共享的水利模拟模型集成架构。在该架构中,借鉴SOA的设计思想,将云服务系统的各项业务分解为颗粒度不同的服务,各子功能封装为标准的web服务。采用SOA典型的模块性特征,将流域模拟模型的集成架构分为客户端、云服务平台、云计算应用程序接口层、模型管理服务层、云服务管理层、物理资源层,使得集成模型的各应用系统的服务来源于各层。该架构增强了水利专业模型平台的开放性、用户交互性以及平台的通用性。

基于MDA的仿真系统开发架构研究

对象管理组织(OMG)提出的模型驱动架构(MDA)是一种先进的软件开发模式,它将系统的设计和实现相分离,设计出的平台无关模型只需建立一次,然后就可以应用于不同的软件平台。本文首先阐述了MDA的思想,然后将MDA的思想和仿真系统开发相结合,建立了一个三层的参考模型,最后分别给出了仿真模型体系和仿真服务体系的实现方法。

多媒体DS-CDMA系统中基于效用函数的无线资源优化策略

本文提出了一种DS CDMA系统上行链路中基于效用函数 (utilityfunction)的无线资源分配策略 .在该模型的框架下 ,我们提出了两种基于效用函数的无线资源分配算法 :URRA EA (Utility basedRadioResourceAllocation Effi ciencyFocused)和URRA UF (Utility basedRadioResourceAllocation UserFocused) .URRA EF旨在追求系统资源的全局最优化 ,而相比之下URRA UF在用户公平性方面更有优势 .为避免非线性优化带来的过高的计算复杂度 ,我们将基于效用函数的无线资源分配问题转换为一个市场模型 ,这样资源的最优配置将以分布式的模式获得 ,因此计算复杂度将大大降低 .仿真结果表明 ,该策略与传统方式相比能够更灵活有效的配置无线多媒体DS CDMA系统中的无线资源 ,其性能提高是显著的 .

osgEarth在三维GIS开发中的研究与应用

针对通用三维GIS平台开发提供了一种基于开源跨平台三维GIS渲染引擎osgEarth的技术方案,并对其中大地形三维模型实时生成和加载、LOD分页数据等关键技术展开了研究。分析了osgEarth的特点和数据加载流程,结合实际项目应用介绍了平台方案的实现及效果,对于工程实践有一定的指导意义。

SOA在模型管理系统中的应用研究

SOA在模型管理中应用旨在解决模型管理系统中数据集成和服务重用问题。训练模拟器开发是一个复杂系统工程,在开发过程中要产生大量的产品数据,包括结构化的和非结构化的。对这些异构的数据进行有效管理,能够为模型开发提供支持,特提出模型管理系统。为了解决开发过程中大量的异构数据的集成问题,提出基于SOA体系结构的模型管理系统。其方法是,利用SOA是一种基于Web服务的松散耦合的体系结构,为模型管理系统提供分阶段实施的策略,降低系统设计的风险,此外,采用SOA的系统结构提高数据和服务接口的可重用性。文章最后给出了基于SOA的系统实现体系结构,解决了模型管理数据集成问题。

基于弱定义Agent的补充勤务维修行为建模

针对补充类勤务过程仿真中补充工作介质和勤务任务种类繁多的特点,引入弱定义Agent概念,给出补充类勤务维修行为模型种类划分、行为层次输出、行为实现等具体过程,构建一种基于弱定义的混合型Agent补充类勤务维修行为模型,旨在提高机务作业训练熟悉程度。通过对黄液压储压器充氮气勤务实例建模验证其可行性和有效性。