CROSSING TIME AND RENEWAL NUMBERS OF TWO PH-RENEWAL PROCESSES

This paper considers how to find some joint distributions and their marginal distributions of crossing time and renewal numbers related to two PH-renewal processes by constructing an absorbing Markov process.

Application of Functional Operators with Shift to the Study of Renewable Systems When the Reproductive Process Is Described by Integrals with Degenerate Kernels

We continue studying systems whose state depends on time and whose resources are renewably based on functional operators with shift. In previous articles, we considered the term which described results of reproductive processes as a linear expression or as a shift summand. In this work, the reproductive term is represented using an integral with a degenerate kernel. A cyclic model of evolution of the system with a renewable resource is developed. We propose a method for solving the balance equation and we determine an equilibrium state of the system. Having applied this model, we can investigate problems of natural systems and their resource production.

Probability Distributions Arising in Connection with the Inspection Paradox for the Poisson Process

The Inspection Paradox refers to the fact that in a Renewal Process, the length of the interarrival period which contains a fixed time is stochastically larger than the length of a typical interarrival period. To provide a more complete understanding of this phenomenon, conditioning arguments are used to obtain the distributions and moments of the lengths of the interarrival periods other than the one containing this fixed time for the case of the time-homogeneous Poisson Process. Distributions of the waiting times for events that occur both before and after this fixed time are derived. This provides a fairly complete probabilistic analysis of the Inspection Paradox.

Necessary Conditions for Renewal Processes Approximating to Wiener Processes

Let {X, X i ; i≥1} be a sequence of i.i.d.r.v’.s, Z (t)= t i=1 X i,t≥0. Consider the renewal process N(t) =inf{x; Z(x) 】t}. In this paper we study the necessary momentconditions for { N(t) ; t≥0} approximating to Wiener processes.Our results have improved those of Csrg, Horváth and Stei, Horváth and Steinebach

更新过程若干矩性质及其风险理论应用

更新过程作为一类重要的计数随机过程,在金融风险理论、可靠性理论等研究领域均具有广泛应用。本文从更新过程的均值函数更新函数有限证明出发,利用其证明思想,进一步研究了更新过程若干矩函数性质,包括任意阶矩函数、指数阶矩函数性质等。最后本文列举了更新过程矩函数性质在风险理论中的一个简单应用。

我国工业领域绿氢发展应用现状与前景分析

以可再生能源制氢替代化石能源制氢是未来工业领域实现绿色低碳转型的主要路径之一,我国水电解制氢技术以碱性电解技术为主,适合波动性新能源的PEM电解技术将有较好的发展前景。从经济性和碳排放两方面对绿氢的竞争力进行了分析,认为目前我国绿氢成本还较高,未来随着新能源电力成本的下降以及碳排放成本的上升,绿氢将逐渐在我国能源体系中发挥重要作用。重点介绍了绿氢发展现状及趋势,分析了绿氢行业存在的主要问题,指出随着我国绿氢化工项目的加速推进,在行业脱碳进程中应重点考虑不要盲目加快绿氢的工业应用进程,需要国家层面在绿氢制备和工业消纳领域出台相应的支持政策,同时建议加快相关标准体系的建设进度。

国土空间规划背景下存量工业用地评价与转型升级策略

国土空间规划背景下存量用地挖潜成为县市级政府获取建设空间的重要来源。工业用地在增量时代扩张较为迅速、粗放,也为更新转型带来挑战。目前,存量工业用地存在评价体系单一、更新规划过程静态化、退出机制缺乏等问题,文章从发展动力和土地绩效双维度,构建存量工业用地评价体系;以动态更新式思维,提供分类型、分时序的引导策略,构建存量工业用地动态开发“一张图”;以新制度经济学为解题范式,提供存量更新的倒逼机制、激励机制和责任机制。

基于AHP-FCE的城市更新效果评价研究

城市更新,是贯彻新时代中国特色社会主义建设的重要城市规划战略。以河北省CD市为例,通过建立层次分析-模糊综合评价模型,对国土空间规划视角下的社会经济发展、资源环境约束、国土空间开发与保障、国土空间保护、国土空间集约利用、国土空间治理与修复等进行评价分析。评价结果显示河北省CD市2022年城市更新效果一般,据此提出了重视生态园林保护、因地制宜合理开发土地等建议,希望对其他城市的建设有所帮助。

农林生物质焚烧电厂运营管理

为我国农林生物质资源丰富,农林生物质作为可再生能源,越来越多机构研究它的利用并投入生产。农林生物质发电是目前针对农林生物质的利用最广泛的一种方式,自2006年至今发展,农林生物质发电规模已达千万千瓦规模,但是农林生物质发电目前还很大程度依赖国家补贴(0.75元/kwh)生存。本文先介绍中国可再生能源的发展、生物质能的发展、农林生物质发电的发展,然后梳理了农林生物质发电厂管理的重难点,从安全管理、环境管理、职业健康管理、燃料管理、两票三制、技改大修等方面进行介绍,以求提高农林生物质发电厂运营管理水平,安健环综合管理体系是农林生物质发电厂健康稳定发展的重要保障,燃料管理是农林生物质发电厂实现效益的重要环节,两票三制管理和技改大修管理是农林生物质发电厂实现设备可持续发展和保障现场安全的重要保障。另外,“双碳”的提出进一步促进了可再生能源发展和研究,希望本文对农林生物质发电厂运营管理、农林生物质的进一步资源化利用、碳减排等的研究能有所帮助。

餐厨垃圾废弃油脂分离的工艺参数优化研究

当前餐厨垃圾的主流处理工艺为厌氧发酵资源化,其前端预处理需尽可能分离废弃油脂以利于有机组分的高效厌氧消化。通过对某餐厨垃圾处理厂预处理工程“清洗脱浆”工艺的研究,选取出影响废弃油脂分离的主要运行参数。经过正交试验设计及实施,探索出具备高油脂得率的运行控制参数,当原料清洗频次为2次,运行温度85℃、停留时间1.0 h,可实现餐厨垃圾废弃油脂得率达86.50%,显著高于传统工艺,此外,系统排出固体废物的油脂率仅为3.69%。

带有投资收益率和双保费复合Poisson-Geometric风险模型的研究

研究了保费收入为线性增长和随机保费的风险模型,且随机保费的保单数服从复合Poisson过程,理赔次数服从复合Poisson-Geometric过程.应用全概率公式和积分变换公式,推导了该模型Gerber-Shiu折现罚金函数满足的更新方程,并当随机保费、理赔过程均服从特定指数分布时,得到了该模型破产概率的解析解,最后通过数值模拟对理论进行了分析验证.

绿氢-绿氨工艺流程的多稳态模拟和动态响应

绿氢-绿氨工艺是指利用可再生能源发电、电解水制氢得到的氢气为原料合成氨的工艺流程,其具有受天气条件影响、负荷波动大、工段间耦合性强的特点。为研究绿氢-绿氨工艺流程中发输变电、电解水制氢、储氢、电化学储能、合成氨等工段之间的系统集成和协同调度方案,利用新一代流程模拟软件AVEVA Process Simulation建立了稳态-动态双模式通用型绿氢-绿氨全流程工艺模型,并通过多稳态模拟的手段分析了系统对天气变化的动态响应。结果表明,合理设计和调度储氢和储能单元不仅可以显著稳定化工生产、合理消纳可再生电力,还能稳定网电补充,提高整体经济效益。

Precise large deviations for sums of random vectors in a multidimensional size-dependent renewal risk model

Consider a multidimensional renewal risk model, in which the claim sizes {Xk, k ≥1} form a sequence of independent and identically distributed random vectors with nonnegative components that are allowed to be dependent on each other. The univariate marginal distributions of these vectors have consistently varying tails and finite means. Suppose that the claim sizes and inter-arrival times correspondingly form a sequence of independent and identically distributed random pairs, with each pair obeying a dependence structure. A precise large deviation for the multidimensional renewal risk model is obtained.

Large Deviations for a Generalized Compound Renewal Risk Model

This paper extends the ordinary renewal risk model to the case where the premium income process,based on a renewal counting process,is no longer a linear function;and the total claim amount process is described by a compound renewal process.For this realistic risk model,the large deviations for the claim surplus process is investigated.

Modeling Abstraction Hierarchy Levels of the Cyber Attacks Using Random Process

Aspects of human behavior in cyber security allow more natural security to the user. This research focuses the appearance of anticipating cyber threats and their abstraction hierarchy levels on the mental picture levels of human. The study concerns the modeling of the behaviors of mental states of an individual under cyber attacks. The mental state of agents being not observable, we propose a non-stationary hidden Markov chain approach to model the agent mental behaviors. A renewal process based on a nonparametric estimation is also considered to investigate the spending time in a given mental state. In these approaches, the effects of the complexity of the cyber attacks are taken into account in the models.

The Development of a Renewable-Energy-Driven Reverse Osmosis System for Water Desalination and Aquaculture Production

Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （RO） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven RO membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.

概率论学习中几个值得注意的问题探究

概率论是随机数学的基础,学好概率论对于金融数学,统计学等学科有着重要的意义。在多年的概率论教学中,以下三点是值得注意的。首先将概率论的历史发展融入概率论教学,这对于学生的理解是有价值的;另外通过比较的方法来学习有助于学生的理解。如比较不同的极限理论可以使得大数定律,中心极限定理更加容易理解;最后,在概率论与随机过程的学习中经常会遇到一些概念性的错误。我们以更新过程中的Feller初等更新定理的证明为例。指出同学们容易产生一些概念性的错误,并将这些错误的原因做出解释,以便让学生对概念的理解更加清晰,避免在概率论与随机过程的学习中犯类似的错误。

Power-Gas-Power可再生能源氢电耦合系统核心工艺设计

绿色、低碳是人类能源利用方式转变的发展趋势,但可再生能源的随机性、间歇性和波动性与电网在时间-空间维度的不协调限制了其充分利用。氢能是高效、绿色可持续的二次能源,电解水制氢技术是目前绿氢的主要来源。Power-Gas-Power氢电耦合系统是以氢储能为媒介,调节能量的储存和转化,是缓解弃风、弃光等问题的有效手段。系统总结了Power-Gas-Power可再生能源氢电耦合系统四个核心工艺的设计过程,包括可再生能源发电系统、绿氢制取系统、绿氢储存系统和燃料电池发电系统,最后指出了可再生能源氢电耦合应用过程面临的问题和相关对策。

New repairable system model with two types repair based on extended geometric process

A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repair finished. When the system failure, the repairman repair it immediately. The time interval of the preventive repair and the failure correction is described with the extended geometric process. Different from the available replacement policy which is usually based on the failure number or the working age of the system, the bivariate policy (T,N) is considered. The explicit expression of the long-run average cost rate function C(T,N) of the system is derived. Through alternatively minimize the cost rate function C(T,N), the optimal replacement policy (T?,N?) is obtained, and it proves that the optimal policy is unique. Numerical cases illustrate the conclusion, and the sensitivity analysis of the parameters is carried out.

基于改进DEAHP法的高比例可再生能源系统脆弱性评估

由于可再生能源间歇性和随机性的运行特点以及不稳定的输出特性与不可控的源动力,电网接入可再生能源时在结构和运行上不可避免地会出现某些难以预料的脆弱特性。通过建立系统多场景规划模型,综合多个角度共同评估电网元件的脆弱性,提出了带有不确定测度的脆弱性评估方法。此方法能够有效识别电网中存在的薄弱节点和支路,可为运行分析人员和调度人员提供电网安全预警信息。