Prediction of efficient outputs based on GM(1,N) model and weak DEA efficiency

This paper expresses the efficient outputs of decisionmaking unit（DMU） as the sum of ＂average outputs＂ forecasted by a GM（1,N） model and ＂increased outputs＂ which reflect the difficulty to realize efficient outputs.The increased outputs are solved by linear programming using data envelopment analysis efficiency theories,wherein a new sample is introduced whose inputs are equal to the budget in the issue No.n ＋ 1 and outputs are forecasted by the GM（1,N） model.The shortcoming in the existing methods that the forecasted efficient outputs may be less than the possible actual outputs according to developing trends of input-output rate in the periods of pre-n is overcome.The new prediction method provides decision-makers with more decisionmaking information,and the initial conditions are easy to be given.

高压管汇材料疲劳性能测试及P-S-N模型曲线的拟合

高压管汇作为压裂设备中的主要易损件之一,其失效危害较大。它的失效原因主要是疲劳、冲蚀、腐蚀或者材料缺陷引起的刺漏和爆裂,其中尤以疲劳失效最不可预估。目前,对于高压管汇材料的疲劳性能研究不够深入,为解决高压管汇材料疲劳寿命的准确描述问题,以某国产高压管汇材料为例,进行了一系列疲劳试验,并基于试验数据,采用多种分布模型和不同S-N模型进行拟合分析,得出综合评价拟合能力最强的P-S-N模型。结果表明,该材料在中长疲劳寿命区,Weibull三参数模型在7级应力水平下综合评价能力最好;在存活率分别为50%、90%、99%、99.9%时,指数S-N模型的拟合系数均大于0.98,拟合能力最好。得出的P-S-N模型曲线可以为高压管汇的疲劳寿命以及安全设计提供依据。

基于改进N-K模型的地铁盾构掘进安全风险耦合研究

为预防和控制地铁盾构掘进施工过程中的关键安全风险,并精准判断哪些风险耦合情境是导致事故发生的显著情境,提出改进N-K模型研究地铁盾构掘进安全风险耦合;综合运用文献研究、事故案例、专家访谈等方法,辨识地铁盾构掘进的关键安全风险因素;基于N-K模型提出新的地铁盾构掘进安全风险耦合评估模型,并选用安全事故案例验证该模型的适用性。结果表明:辨识得到地铁盾构掘进关键安全风险因素清单,包括4类一级风险因素,21个二级风险因素;地铁盾构掘进施工安全风险随着耦合因素种类的增加而变大,4因素风险耦合值最高,3因素风险耦合值次之,双因素风险耦合值最低,作业人员安全意识薄弱和机械故障参与作用的耦合情境更容易发生安全事故。

基于DEMATEL/N-K的机坪管制系统运行风险因素耦合分析

为了分析机坪管制系统风险因素的耦合性,将决策实验室分析(DEMATEL)模型与N-K模型相结合形成新的风险因素耦合分析模型。首先,利用N-K模型对2017—2019年机坪管制运行不安全事件进行耦合分析,计算不同耦合方式的耦合值;然后,利用DEMATEL模型计算安全风险因素的影响度和被影响度,确定要素的中心度排序,通过DEMATEL模型得到的综合影响矩阵计算可达矩阵,用来分析风险因素的可达性,最后,利用风险因素耦合值对各风险节点的中心度进行修正,获得关键的风险因素。基于实际运行数据,通过DEMATEL/N-K模型分析机坪管制系统的关键风险因素。结果表明,人为因素和机械因素之间的耦合程度明显更高,即更容易导致事故的发生,其中地面保障人员操作出错或未有效观察航空器造成航空器或地面保障设备故障是重点防控的对象。此外,在夜晚或雨天等视线条件下工作,更容易发生不安全事件,应当采取措施控制此类风险。

N-Calculator与NUFER耦合模型和组合预测法在食物氮足迹研究中的应用

为改善传统N-Calculator模型的局限性,加强食物氮足迹核算结果与环境影响的联系,提高活性氮管理预见性,将N-Calculator模型与食物系统养分流动(Nutrient Flows in Food Chains,Environment and Resources Use,NUFER)模型进行耦合,以估算我国2001—2020年人均食物氮足迹,建立组合预测体系。结果显示:2001—2020年,我国人均食物氮足迹由16.04 kg N/a增至18.95 kg N/a;全国食物氮足迹由20.47 Mt N/a增至26.76 Mt N/a;居民饮食结构正由以植物源食物为主的低氮消费模式转向以动物源食物为主的高氮消费模式;食物生产过程产生的活性氮的最终归宿为大气(64.3%)、水体和深层土壤(35.7%);我国食物氮足迹与人均可支配收入、城市化率、动物源食物消费氮占比呈正相关性,与恩格尔系数呈负相关性;未来10 a我国人均食物氮足迹呈增长趋势,预测结果显示年均增幅为0.16 kg N/a。

融合N-K模型的复杂网络船舶自沉事故风险因素耦合分析

为定量分析船舶自沉风险因素间的影响关系,识别导致船舶自沉事故的关键因素,科学预防事故的发生,引入融合N-K模型的复杂网络研究船舶自沉事故风险耦合。首先结合中国海事局公布的136起船舶自沉事故案例,分析事故致因,将船舶自沉事故风险因素归纳为4个一级风险因素和15个二级风险因素,运用N-K模型计算出一级风险因素风险耦合的发生概率和风险值;然后,以二级风险因素为节点、致因关联为边,构建危险因子的关联网络,通过风险可达性分析和网络节点中心度分析,探究危险因子的作用机制,对危险因子进行初步识别,并以N-K模型计算的耦合值对节点中心度进行改进,获得最终的关键风险因素;最后,挖掘船舶自沉事故致因网络的凝聚子群并进行分析,得到密度矩阵,确定风险关联性最强的二级风险因素,以期从事故源头上采取有效措施,为船舶自沉事故的科学预防提供有益参考。结果表明:船舶自沉事故的发生与风险耦合值成正比,耦合因素越多则风险值越大;人的因素和船舶因素风险耦合易导致船舶自沉事故;导致船舶自沉事故的关键风险因素为安全意识淡薄、公司未履责、船舶管理不到位、公司管理不到位、船舶故障、船舶不适航,其中安全意识淡薄与其他风险关联性最大,须重点防范。

基于新型“1+X+N”人才培养模式的一流本科课程建设探索

为了适应时代的发展需求,响应国务院提出的在应用型本科高校启动“学历证书+若干职业技能等级证书”制度(即“1+X”证书制度)的试点工作,民办本科院校积极探索“1+X+N”人才培养新模式。在人才培养新模式下,省级一流本科课程光纤通信技术课程组从明确课程定位、推动教学改革、加大资源建设、优化教学内容与实施过程、推进课程思政、改善课程成绩评定等方面开展工作,努力提升学生在光纤通信方面的综合应用能力,培养出满足新时代通信发展需求的高质量人才。

医学院校思政课“1+3+N”教学实践探析

“1+3+N”教学模式围绕医学院校特色、医学专业和医学生特点,基于移动互联技术,坚持以学生为中心,有机融合网络教学、课堂教学和实践教学3种集中教学形式,辅以N种分散教学形式,实现思政课与医学生医学梦的同频共振。学生通过网络课堂预习基本知识点,教师在课堂教学中着重讲解重难点并解答学生预习遇到的问题,学生通过实践教学把所学理论知识内化于心、外化于行。小班讨论等N种分散教学形式旨在培养学生听、读、看、写、讲、行能力。“1+3+N”教学模式弥补了传统灌输式授课方式的短板,调动了医学生学习思政课的积极性和主动性。影响该教学模式实践效果的因素包括学校网络教学基础设施和信息化教学设备情况、师生相关技术掌握情况、网络教学管理情况、网络教学和课堂教学衔接情况、实践教学组织实施情况等,针对这些影响因素,采取相应优化策略,以提升教学效果。

基于N-K模型的石化储罐事故风险耦合度分析

为预防石化储罐事故,通过收集212份石化储罐事故报告,将事故风险因素归纳为人为、设备、环境、管理4个类别,利用N-K模型分析事故风险因素之间的耦合作用,并运用N-K模型计算各种耦合模式下的风险耦合度,得出了石化储罐事故风险因素的耦合关系及耦合作用规律。结果表明,随着参与耦合的因素增多,风险耦合值总体呈现上升趋势;人为因素与其它因素耦合更容易导致事故;石化储罐区事故各风险因素之间的耦合作用程度相比其它行业更高。研究结果可为石化企业储罐事故管控提供依据和参考。

Analysis of a multi-patch dynamical model about cattle brucellosis

The dissemination of cattle brucellosis in Zhejiang province of China can be attributed to the transport of cattle between cities within the province. In this paper,an n-patch dynamical model is proposed to study the effect of cattle dispersal on brucellosis spread. Theoretically,we analyze the dynamical behavior of the muti-patch model. For the 2-patch submodel,sensitivity analyses of the basic reproduction number R0 and the number of the infectious cattle in term of model parameters are carried out. By numerical analysis,it is obtained that the dispersal of susceptible cattle between patches and the centralization of infected cattle to the large scale patch can alleviate the epidemic and are in favor of the control of disease in the whole region.

Monte Carlo study of the universal area distribution of clusters in the honeycomb O(n) loop model

We investigate the area distribution of clusters （loops） in the honeycomb O（n） loop model by means of the worm algorithm with n = 0.5, 1, 1.5, and 2. At the critical point, the number of clusters, whose enclosed area is greater than A, is proportional to A-1 with a proportionality constant C. We confirm numerically that C is universal, and its value agrees well with the predictions based on the Coulomb gas method.

Incorporating Linguistic Rules in Statistical Chinese Language Model for Pinyin-to-character Conversion

An N-gram Chinese language model incorporating linguistic rules is presented. By constructing elements lattice, rules information is incorporated in statistical frame. To facilitate the hybrid modeling, novel methods such as MI-based rule evaluating, weighted rule quantification and element-based n-gram probability approximation are presented. Dynamic Viterbi algorithm is adopted to search the best path in lattice. To strengthen the model, transformation-based error-driven rules learning is adopted. Applying proposed model to Chinese Pinyin-to-character conversion, high performance has been achieved in accuracy, flexibility and robustness simultaneously. Tests show correct rate achieves 94.81% instead of 90.53% using bi-gram Markov model alone. Many long-distance dependency and recursion in language can be processed effectively.

A Process-based Model of N_2O Emission from a Rice-Winter Wheat Rotation Agro-Ecosystem:Structure,Validation and Sensitivity

In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.

基于事故树的N-K模型施工事故风险耦合分析

为了研究水平定向钻施工事故风险,考虑事故树定性分析与N-K模型(N为系统的组件数量,K为每个组件与其他组件的交互数量)定量分析方法的缺点,从人为、设备、环境及管理4类风险因素构建一种基于事故树的N-K施工事故风险分析综合模型。通过建立事故树施工底层事件与N-K模型耦合风险因素集合映射关系,分别计算单因素、双因素以及多因素耦合风险概率,求解风险耦合值。结果表明:水平定向钻施工事故风险概率随着风险耦合因素的增加而增大;三因素耦合作用时,设备-环境-管理耦合作用值最大为0.2608,人为-设备-管理次之为0.2034;双因素耦合作用时,环境-管理耦合作用值最大为0.1554;水平定向钻施工事故共有50种引发事故的可能途径,可以按照准备阶段、导向孔钻进阶段、扩孔阶段、管道回拖阶段与规划管理阶段对整体事故风险进行分阶段预防。研究成果一方面可为风险研究提供新的综合模型,另一方面也可为水平定向钻安全施工提供重要的参考依据。

复合材料层压板S-N曲线模型的综述与评估

S-N模型是分析预测材料及其结构疲劳寿命的重要基础。本文对复合材料层压板的S-N曲线模型进行了全面综述,并将其归纳为基于数据拟合思想的经验模型和考虑损伤机理的半经验模型。研究发现,应力比是S-N模型需要考虑的关键载荷参数,而包含应力比的半经验模型较少、经验模型更为匮乏。拟定了模型评估五个基本标准,选取了两种材料体系、不同铺层结构层合板在不同应力比条件下的八组疲劳数据,对典型S-N模型的表征能力进行了分析评估。结果表明:Weibull模型、Wu模型和Epaarachchi模型在不同疲劳影响因素下均能表现出较强的拟合能力,整体拟合精度较高,而且Weibull模型和Wu模型具有拟合S-N曲线全区间的能力;Basquin模型虽然在理论和工程中经常使用,但预测精度通常并不理想;相较于不包含应力比的模型,包含应力比的模型其表征精度通常比较差,适用范围反而受限;同时,与半经验模型相比,经验模型通常满足边界条件,对不同形式S-N曲线的拟合优度更高,适应能力更强,且适用范围更广。

Optimizing Parameters of CSM-CERES-Maize Model to Improve Simulation Performance of Maize Growth and Nitrogen Uptake in Northeast China

Crop models can be useful tools ibr optimizing fertilizer management for a targeted crop yield while minimizing nutrient losses. In this paper, the parameters of the decision support system for agrotechnology transfer （DSSAT）-CERES-Maize were optimized using a new method to provide a better simulation of maize （Zea mays L.） growth and N upfake in response to different nitrogen application rates. Field data were collected from a 5 yr field experiment （2006-2010） on a Black soil （Typic hapludoll） in Gongzhuling, Jilin Province, Northeast China. After cultivar calibration, the CERES-Maize model was able to simulate aboveground biomass and crop yield of in the evaluation data set （n-RMSE=5.0-14.6%）, but the model still over-estimated aboveground N uptake （i.e., with E values from -4.4 to -21.3 kg N ha-~）. By analyzing DSSAT equation, N stress coefficient for changes in concentration with growth stage （CTCNP2） is related to N uptake. Further sensitivity analysis of the CTCNP2 showed that the DSSAT model simulated maize nitrogen uptake more precisely after the CTCNP2 coefficient was adjusted to the field site condition. The results indicated that in addition to calibrating 6 coefficients of maize cultivars, radiation use efficiency （RUE）, growing degree days for emergence （GDDE）, N stress coefficient, CTCNP2, and soil fertility factor （SLPF） also need to be calibrated in order to simulate aboveground biomass, yield and N uptake correctly. Independent validation was conducted using 2008-2010 experiments and the good agreement between the simulated and the measured results indicates that the DSSAT CERES-Maize model could be a useful tool for predicting maize production in Northeast China.

青海省五龙沟地区基于W-N多重分形模型的Au地球化学异常识别

五龙沟地区位于东昆仑造山带东段,由于经历了复杂的地质演化过程,形成了极为复杂的地球化学背景,难以使用统一的异常下限精确提取地球化学异常。本文基于1∶5万水系沉积物地球化学数据,综合运用W-N多重分形模型和因子分析方法对研究区内与Au矿化有关的地球化学异常进行提取,并与传统的S-A多重分形模型提取结果进行对比。结果表明,通过因子分析获得的第三因子(F3)元素组合为Au-As-Sb,代表了研究区内与Au矿化有关的元素组合。W-N模型能够抑制研究区内复杂背景的干扰,强化弱异常,与S-A模型相比,使用W-N模型处理数据所获得的异常图与金矿床位置的吻合度更高,可以为地质找矿工作提供有利的信息。

A Preliminary Study on Dynamics and Models of N,P,K Absorption for High-Yield Cotton

The field experiments were carried out to investigate the dynamics and models of N, P and K absorption for the cotton plants with a lint of 3 000 kg ha-1 in Xinjiang. The main results were as follows: The contents of N, P2O5, K2O in cotton leaves, stems, squares and bolls decreased obviously with the time over the whole growth duration and the falling extent was greater in high-yield cotton than in CK. Contents of N in leaves, squares and bolls, in particular in the leaves of fruit-bearing shoot was higher in high-yield cotton than in CK. Contents of P2O5 in squares and bolls and that of K2O in stems were higher in high-yield cotton than in CK during the whole growing period. The accumulations of N, P2O5 and K2O in the cotton plants could be described with a logistic curve equation. There was the fastest nutrient uptake at about 90 d for N, 92 d for P2O5 and 85 d for K2O after emergence, respectively. Total nutrient accumulation of N, P2O5 and K2O was 385.8, 244. 7 and 340.3 kg ha-1, respectively. Approximately 12. 5 kg N, 8. 0 kg P2O5 and 11.1 kg K2O were needed for producing 100 kg lint with the leaves and stems under the super high yield condition of 3 000 kg ha-1 in Xinjiang.

Modeling of a welding robot system with time delay

A new real time control model based on the fundamental Petri net theory is built for a complete close loop welding robot system with time delay. The new Petri net model synchronizes with devices at the primary level by introducing into the basic Petri net expression new parameters which contain the responding real time information. In addition, time delay is taken into account by adding some necessary time related parameters. Usually, in a system without time delay, if the condition is enabled, the transition must be fired, but in a system with time delay, this property is only a necessary but not a sufficient condition.

融合N-K模型社会网络的化工企业爆炸风险因素耦合研究

为揭示我国化工企业爆炸事故风险因素耦合特性,并识别关键风险因素,将风险因素划分为人、机、环、管4类,风险耦合形式界定为单因素、双因素和多因素风险耦合3类,进而采用N-K模型测度风险耦合水平,运用社会网络分析(Social Network Analysis,SNA)模型分析风险因素节点的中心度及可达性,并结合风险因素耦合水平测度结果和风险因素节点分析结果确定化工企业爆炸关键风险因素,据此提出防控建议。结果表明:风险因素耦合水平与参与因素的数量成正比,4类因素耦合水平最高,且人员风险对耦合影响较大;现场安全管理不到位,安全风险分析或隐患排查不全面,监理、安评等单位依法履职不到位,变更管理制度存在缺陷,安全生产信息档案不全是需要重点防范的关键风险因素。