Long-term prediction model of rockburst in underground openings using heuristic algorithms and support vector machines

Rockburst possibility prediction is an important activity in many underground openings design and construction as well as mining production. Due to the complex features of rockburst hazard assessment systems, such as multivariables, strong coupling and strong interference, this study employs support vector machines (SVMs) for the determination of classification of long-term rockburst for underground openings. SVMs is firmly based on the theory of statistical learning algorithms, uses classification technique by introducing radial basis function (RBF) kernel function. The inputs of models are buried depth H, rocks’ maximum tangential stress σ_θ, rocks’ uniaxial compressive strength σ_c, rocks’ uniaxial tensile strength σ_t, stress coefficient σ_θ/σ_c, rock brittleness coefficient σ_c/σ_t and elastic energy index W_et. In order to improve predictive accuracy and generalization ability, the heuristic algorithms of genetic algorithm (GA) and particle swarm optimization algorithm (PSO) are adopted to automatically determine the optimal hyper-parameters for SVMs. The performance of hybrid models (GA + SVMs = GA-SVMs) and (PSO + SVMs = PSO-SVMs) have been compared with the grid search method of support vector machines (GSM-SVMs) model and the experimental values. It also gives variance of predicted data. A rockburst dataset, which consists of 132 samples, was employed to evaluate the current method for predicting rockburst grade, and the good results of overall success rate were obtained. The results indicated that the heuristic algorithms of GA and PSO can speed up SVMs parameter optimization search, the proposed method is robust model and might hold a high potential to become a useful tool in rockburst prediction research.     

层次分析法在生活垃圾处置方案优选中的应用

对于如城市生活垃圾处置技术方案优选这类多目标、多方案决策问题,特别是在决策缺乏充分的信息支持前提时,AHP分析法的若干特点,显示其作为一种系统工程的理论工具具有一定的客观性、准确性和有效性,是一种简易而且可行的理论方法和手段。通过以某经济开发区生活垃圾处置方案的优选为例进行了探讨。     

A Revealed Preference Approach to Estimating Supply Curves for Ecosystem Services: Use of Auctions to Set Payments for Soil Erosion Control in Indonesia

Abstract:  To supply ecosystem services, private landholders incur costs. Knowledge of these costs is critical for the design of conservation-payment programs. Estimating these costs accurately is difficult because the minimum acceptable payment to a potential supplier is private information. We describe how an auction of payment contracts can be designed to elicit this information during the design phase of a conservation-payment program. With an estimate of the ecosystem-service supply curve from a pilot auction, conservation planners can explore the financial, ecological, and socioeconomic consequences of alternative scaled-up programs. We demonstrate the potential of our approach in Indonesia, where soil erosion on coffee farms generates downstream ecological and economic costs. Bid data from a small-scale, uniform-price auction for soil-conservation contracts allowed estimates of the costs of a scaled-up program, the gain from integrating biophysical and economic data to target contracts, and the trade-offs between poverty alleviation and supply of ecosystem services. Our study illustrates an auction-based approach to revealing private information about the costs of supplying ecosystem services. Such information can improve the design of programs devised to protect and enhance ecosystem services.     

The dynamic response of pressure relief valves in vapor or gas service. Part II: Experimental investigation

An experimental testing program designed to evaluate the opening stability characteristics of direct acting pressure relief valves (PRV) in gas/vapor service is described. Three different valve sizes from each of three different manufacturers were tested at two different set pressures to determine their opening characteristics (disk lift vs. time). The valves were tested with several different lengths of inlet piping as well as with and without discharge piping to determine the conditions under which unstable operation (chatter) would occur. Part I of this program described a mathematical model for predicting the dynamic response of PRV's, and the data described in this test program were used to evaluate the accuracy of the model, as described in Part III of this study to follow.     

Determining the community structure of the coral Seriatopora hystrix from hydrodynamic and genetic networks

The exchange of genetic information between coral reefs through the transport of larvae can be described in terms of networks that capture the linkages between distant populations. A key question arising from these networks is the determination of the highly connected modules (communities). Communities can be defined using genetic similarity or distance statistics between multiple samples but due to limited specimen sampling capacity the boundaries of the communities for the known coral reefs in the seascape remain unresolved. In this study we use the microsatellite composition of individual corals to compare sample populations using a genetic dissimilarity measure (F_ST) which is then used to create a complex network. This network involved sampling 1025 colonies from 22 collection sites and examining 10 microsatellites loci. The links between each sampling site were given a strength that was created from the pair wise F_ST values. The result is an undirected weighted network describing the genetic dissimilarity between each sampled population. From this network we then determined the community structure using a leading eigenvector algorithm within graph theory. However, given the relatively limited sampling conducted, the representation of the regional genetic structure was incomplete. To assist with defining the boundaries of the genetically based communities we also integrated the communities derived from a hydrodynamic and distance based networks. The hydrodynamic network, though more comprehensive, was of smaller spatial extent than our genetic sampling. A Bayesian Belief network was developed to integrate the overlapping communities. The results indicate the genetic population structure of the Great Barrier Reef and provide guidance on where future genetic sampling should take place to complete the genetic diversity mapping.     

安全工程本科专业建设研究的文献计量学分析

为了解安全科技人员利用文献的特点和安全工程学科文献的发展规律,根据文献计量学分析理论与方法,对1995—2009年安全工程本科专业建设研究文献的发文量、文献著者、核心作者群、核心期刊群、引文文献、被引用情况和基金项目资助等进行分析研究,结果表明:安全工程本科专业建设研究的发文量较少但整体呈上升态势;文献著者的合作度为2.5,合著率76.1%,文献的合作度和合著率较低,研究深度和广度需进一步加强,同时需加强多单位联合研究;高校研究者是该领域的主力军,其发文量占92.5%,但核心作者群尚未形成;《中国安全科学学报》是该领域研究的核心期刊,北京是该领域研究的核心区域;期刊文献是主要的引文类型(73.5%),引文语种主要是中文文献(97.3%),篇均引文文献4.9篇,普赖斯指数较高(73.3%);文献的被引用频次整体较低(2.2);2005年以来文献的基金项目资助率为30.2%,基金项目资助率和资助项目级别均呈上升趋势。     

基于马尔科夫链-多目标模型的应急供应链决策优化研究

为应对洪涝、新冠肺炎疫情等突发灾难,提出供应物资满足率最大、供应时间最短、供应成本最低的离散时间马尔科夫链-多目标规划模型(DTMC-MOP),动态地识别、分析、应对应急供应链风险;采用改进自适应NSGA-Ⅱ算法求解优化模型,并通过标准测试函数进行测试与评价,验证模型的可行性和有效性;通过算例分析,获得精度更高、分布更均匀的Pareto最优前沿。研究结果表明：决策者可以依据应急管理核心目标或不同偏好选择相适应的应急方案,研究结果可为应急供应链决策优化提供1种科学方法,对保障灾民生命安全、维护社会和谐稳定具有积极意义。     

300MW机组电袋复合除尘器的应用探讨

通过技术、经济比较,确定了宁夏大坝发电有限责任公司3号机组电除尘器改造为电袋复合除尘器的方案。改造后电袋除尘器各项指标均达到设计要求,保证300MW发电机组满负荷运行。     

干酵母生产废水处理方案的改造及应用

干酵母生产废水是一种高浓度有机废水,COD高达13,000mg/L,色度在900倍以上。原方案采用厌氧、硝化(曝气)、反硝化、化学混凝等工艺,但水质不能达到排放标准,且运行成本高。采用EM(有效微生物)技术对原方案进行改造后,废水处理收到较好的效果,并降低了运行成本。     

The Future of Baltic Sea Populations: Local Extinction or Evolutionary Rescue?

Environmental change challenges local and global survival of populations and species. In a species-poor environment like the Baltic Sea this is particularly critical as major ecosystem functions may be upheld by single species. A complex interplay between demographic and genetic characteristics of species and populations determines risks of local extinction, chances of re-establishment of lost populations, and tolerance to environmental changes by evolution of new adaptations. Recent studies show that Baltic populations of dominant marine species are locally adapted, have lost genetic variation and are relatively isolated. In addition, some have evolved unusually high degrees of clonality and others are representatives of endemic (unique) evolutionary lineages. We here suggest that a consequence of local adaptation, isolation and genetic endemism is an increased risk of failure in restoring extinct Baltic populations. Additionally, restricted availability of genetic variation owing to lost variation and isolation may negatively impact the potential for evolutionary rescue following environmental change.