互联网环境下消费信贷行为研究

采用结构方程建模方法,实证分析了感知易用性、感知有用性、感知风险、信用卡效应及使用的态度与互联网环境下消费者使用信用卡支付的意愿之间的作用路径关系,从而建立了互联网环境下消费信贷行为影响因素的概念模型．研究表明,除感知风险与使用的意愿之间存在负相关关系外,其余四个因素与使用的意愿之间均存在正相关关系,其中使用的态度对使用的意愿的影响最大．     

移动互联的金融梦

过去半年当中,在PC上使用软件客户端的用户,下降了7．9％;在PC上使用网页的用户,下降了15．4％。而使用移动APP和使用移动浏览器看网页的用户,在过去8个月当中增长超过了40％。     

CPM网络中机动时间的使用效率及应用

本文研究CPM网络计划中总时差和单时差的使用效率问题及在项目管理中的应用.文章首先探讨了总时差和自由时差的使用对CPM网络中新关键路线形成的影响,得出结论:一般情况下一条路线上各工序分别使用自由时差的方式比某个工序使用总时差的方式具有更高的使用效率.文章随后对这一结论进行了科学性证明,并根据这个结论提出了项目管理中一种运用自由时差节约成本的方法,这种方法能帮助项目管理者提高机动时间使用效率.     

考虑使用成本的软件交易方式选择研究

用户使用软件过程中往往需要支付数额不菲的各种成本。永久授权交易方式下,软件使用成本完全由用户负担;软件即服务交易方式下,部分使用成本(如软硬件维护成本)转由软件供应商负担,且供应商借助专业优势通常能压缩其分担的使用成本。对于永久授权和软件即服务两种交易方式,本文分别建立垄断软件供应商的两阶段定价模型,分析用户选择和供应商定价策略,考察软件使用成本、供应商分担部分使用成本及供应商成本压缩在软件交易方式选择中的作用。研究发现,当软件使用成本较高、供应商分担使用成本的比例较大、供应商压缩成本幅度较大时,软件即服务交易方式通常占优;否则,永久授权交易方式通常占优。     

农户家庭天然气接入意愿与持续使用行为——基于陕西案例的UTAUT模型实证分析

在我国广袤的农村,天然气入户是清洁绿色能源革命的重要内容。运用技术接受使用统一模型即UTAUT,以陕西省为案例对象,研究农户家庭对天然气的接入意愿和持续使用行为。结果表明,感知风险、便利条件、绩效预期和社群影响4个方面由强至弱对农村家庭天然气的接入意愿具有正向显著影响。其中,接入意愿正向显著影响持续使用行为,而便利条件不能直接对持续使用行为构成显著影响。年龄、家庭人均年收入分别对绩效预期影响接入意愿具有显著调节作用,人均年收入越高的农户对天然气及其使用预期越高,40~60岁农家主事者对天然气及使用有更高的接入意愿;使用经历对感知风险、社群影响作用于接入意愿具有调节效应。为此,政府部门应强化引导作用,及时出台系统化、完整的一揽子农村天然气推广政策;燃气企业多方组织气源,保障燃气供应,在加强成本核算的同时提供合格的燃气服务和技术支持;农民个人积极增加收入,转变能源消费观念,学习、掌握和安全使用天然气;鼓励有燃气使用经历的农户先行接入使用,辐射带动邻居、亲友接受天然气能源使用。     

基于序关系法和模糊综合评价法的西安市应急标识有效性评估

为研究西安市应急标识使用效果,运用文献综述法,结合西安市人群聚集场所应急标识实际使用情况,总结出20个影响因素建立西安市应急标识有效性评价指标体系.通过序关系法确定20个影响因素的权重,使用模糊综合评价法综合评价西安市应急标识的使用效果.结果表明:西安市应急标识使用效果较好.从优化标识设计、提高居民应急技能等方面可以提高应急标识有效性.     

中学生数学教科书使用倾向研究

教科书在课程的学习中发挥着重要作用,将其作为教学资源的研究众多.然而,随着“以学生为中心”的教育理念深入,学生作为课堂的主体,其对教科书的使用也受到广泛关注.本研究通过问卷调查对学生使用教科书的倾向进行定量研究,研究建立了与“使用”一词相关的六种指标(频率、时间、目的、动机、偏好)来体现学生对数学教科书的使用情况.研究结果表明,中学生对教科书的使用主要受教师以及学生自身调节意识的影响.学生使用教科书主要是用于预习,课内学习以及练习,部分学生用于查阅实例以及将其视为参考资料和拓展性习题资料使用,学生倾向于将教科书作为认识概念的字典、解题的模板、备考的指导所使用.     

基于均衡使用的通用教练机使用计划编排算法

为确保教练机在飞行训练中的均衡使用,构造描述"训练任务"衔接关系的时序网络模型,以此将教练机均衡使用问题转化为时序网络图上寻找教练机执飞"训练任务"的路径计划问题,通过建立满足教练机均衡使用要求的目标函数,为"训练任务"随机赋予教练机编号生成"训练任务"路径计划,进而设计模拟退火算法获取教练机使用计划方案.选取国内某飞行航校"10架教练机、37个训练任务"的训练计划进行分析,结果表明:算法能够提高教练机使用的均衡性;随着训练任务之间衔接松散度的增加,教练机使用计划方案的均衡更好.     

再使用产品的质量判断研究

再使用产品是回收产品再利用的第一优先级.给出了再使用产品的定义,并利用数据包络分析方法对其进行了质量判断.通过案例分析,说明该模型用于再使用产品质量判断是可行的和有效的.     

三种类型汽车的能耗和使用成本的建模研究

本文对电动,传统,混合动力三种类型汽车的能耗和使用成本问题进行了建模、求解及分析．首先定义了电动汽车的能量利用率ηE。根据能量守恒将所有电量转换成汽油消耗量,而传统车型则直接反映到汽油的消耗上,混合动力汽车则综合电动汽车和传统汽车的能耗模型,从而统一能耗水平评价标准．这样,我们就得到了三种不同类型车的能耗模型再进行模型求解以此来分析比较三种类型车哪一种节能效果好．对电动汽车来说,使用成本主要包括驾驶维护成本、报废处理成本,而对传统汽车来说,使用成本主要包括驾驶维护成本、报废处理成本、环境成本和其他成本,混合动力汽车则结合二者使用成本．因此,根据不同车型使用成本类型建立相应的数学模型,按照建立的公式,可以得到电动汽车的使用成本LCC1、传统汽车的使用成本LCC2和混合动力汽车的使用成本LCC3,从而进行模型求解．     

Fourth-order compact schemes with adaptive time step for monodomain reaction–diffusion equations

Multigrid applied to fourth-order compact schemes for monodomain reaction–diffusion equations in two dimensions has been developed. The scheme accounts for the anisotropy of the medium, allows for any cellular activation model to be used, and incorporates an adaptive time step algorithm. Numerical simulations show up to a 40% reduction in computational time for complex cellular models as compared to second-order schemes for the same solution error. These results point to high-order schemes as valid alternatives for the efficient solution of the cardiac electrophysiology problem when complex cellular activation models are used.     

The shape of the hazard function for cancer incidence

A population-based cohort consisting of 126,141 men and 122,208 women born between 1874 and 1931 and at risk for breast or colorectal cancer after 1965 was identified by linking the Utah Population Data Base and the Utah Cancer Registry. The hazard function for cancer incidence is estimated from left truncated and right censored data based on the conditional likelihood. Four estimation procedures based on the conditional likelihood are used to estimate the age-specific hazard function from the data; these were the life-table method, a kernel method based on the Nelson Aalen estimator, a spline estimate, and a proportional hazards estimate based on splines with birth year as sole covariate.The results are consistent with an increasing hazard for both breast and colorectal cancer through age 85 or 90. After age 85 or 90, the hazard function for female breast and colorectal cancer may reach a plateua or decrease, although the hazard function for male colorectal cancer appears to continue to rise through age 105. The hazard function for both breast and colorectal cancer appears to be higher for more recent birth cohorts, with a more pronounced birth-cohort effect for breast cancer than for colorectal cancer. The age specific for colorectal cancer appears to be higher for men than for women. The shape of the hazard function for both breast and colorectal cancer appear to be consistent with a two-stage model for spontaneous carcinogenesis in which the initiation rate is constant or increasing. Inheritance of initiated cells appears to play a minor role.     

A Method of Systematic Search for Optimal Multipliers in Congruential Random Number Generators

This paper presents a method of systematic search for optimal multipliers for congruential random number generators. The word-size of computers is a limiting factor for development of random numbers. The generators for computers up to 32 bit word-size are already investigated in detail by several authors. Some partial works are also carried out for moduli of 2⁴⁸ and higher sizes. Rapid advances in computer technology introduced recently 64 bit architecture in computers. There are considerable efforts to provide appropriate parameters for 64 and 128 bit moduli. Although combined generators are equivalent to huge modulus linear congruential generators, for computational efficiency, it is still advisable to choose the maximum moduli for the component generators. Due to enormous computational price of present algorithms, there is a great need for guidelines and rules for systematic search techniques. Here we propose a search method which provides ‘fertile’ areas of multipliers of perfect quality for spectral test in two dimensions. The method may be generalized to higher dimensions. Since figures of merit are extremely variable in dimensions higher than two, it is possible to find similar intervals if the modulus is very large. This revised version was published online in July 2006 with corrections to the Cover Date.     

Weak solutions for equations defined by accretive operators II: relaxation limits

In the first part of this paper we define solutions for certain nonlinear equations defined by accretive operators, “dissipative solution”. This kind of solution is equivalent to the viscosity solutions for Hamilton-Jacobi equations and to the entropy solutions for conservation laws.In this paper we use dissipative solutions to obtain several relaxation limits for systems of semilinear transport equations and quasilinear conservation laws. These converge to diffusion second-order equations and in one case to a single conservation law. The relaxation limit is obtained using a version of the perturbed test function method to pass to the limit. This guarantees existence for the considered equations.     

Quillen’s stratification for fusion systems

The purpose of this note is to provide a reference for the fact that the proof of Quillen’s stratification for finite group cohomology carries over to fusion system. As in the case of Quillen’s stratification for block varieties, the proof is similar to the usual proof for group cohomology except for the use of fusion stable bisets, whose existence is due to Broto et al.     

考虑多救援点的突发事件应急救援人员派遣模型

针对具有多救援点的突发事件应急救援人员派遣问题,给出了一种应急救援人员派遣模型。首先,依据救援人员关于救援任务的能力指标评价值计算出不同出救点的救援人员对救援点中救援任务的胜任度;其次,依据救援人员到达救援点的应急救援时间计算出应急救援时间满意度;然后,将救援人员对救援点的胜任度与应急救援时间满意度进行集结,获得应急救援人员与各救援点的综合匹配度;进一步地,以综合匹配度最大为目标,构建应急救援人员派遣优化模型,并通过模型求解获得最优的应急救援人员派遣方案;最后,通过一个算例说明了所构建的应急救援人员派遣模型具有可用性。     

Conservation laws via the partial Lagrangian and group invariant solutions for radial and two-dimensional free jets

The conservation laws for Prandtl’s boundary layer equations for an incompressible fluid governing the flow in radial and two-dimensional jets are investigated. For both radial and two-dimensional jets the partial Lagrangian method is used to derive conservation laws for the system of two differential equations for the velocity components. The Lie point symmetries are calculated for both cases and a symmetry is associated with the conserved vector that is used to establish the conserved quantity for the jet. This associated symmetry is then used to derive the group invariant solution for the system governing the flow in the free jet.     

Securitization, structuring and pricing of longevity risk

Pricing and risk management for longevity risk have increasingly become major challenges for life insurers and pension funds around the world. Risk transfer to financial markets, with their major capacity for efficient risk pooling, is an area of significant development for a successful longevity product market. The structuring and pricing of longevity risk using modern securitization methods, common in financial markets, have yet to be successfully implemented for longevity risk management. There are many issues that remain unresolved for ensuring the successful development of a longevity risk market. This paper considers the securitization of longevity risk focusing on the structuring and pricing of a longevity bond using techniques developed for the financial markets, particularly for mortgages and credit risk. A model based on Australian mortality data and calibrated to insurance risk linked market data is used to assess the structure and market consistent pricing of a longevity bond. Age dependence in the securitized risks is shown to be a critical factor in structuring and pricing longevity linked securitizations.     

A Bayesian approach to the triage problem with imperfect classification

A collection of jobs (or customers, or patients) wait impatiently for service. Each has a random lifetime during which it is available for service. Should this lifetime expire before its service starts then it leaves unserved. Limited resources mean that it is only possible to serve one job at a time. We wish to schedule the jobs for service to maximise the total number served. In support of this objective all jobs are subject to an initial triage, namely an assessment of both their urgency and of their service requirement. This assessment is subject to error. We take a Bayesian approach to the uncertainty generated by error prone triage and discuss the design of heuristic policies for scheduling jobs for service to maximise the Bayes’ return (mean number of jobs served). We identify problem features for which a high price is paid in number of services lost for poor initial triage and for which improvements in initial job assessment yield significant improvements in service outcomes. An analytical upper bound for the cost of imperfect classification is developed for exponentially distributed lifetime cases.