Likelihood approximation by numerical integration on sparse grids

The calculation of likelihood functions of many econometric models requires the evaluation of integrals without analytical solutions. Approaches for extending Gaussian quadrature to multiple dimensions discussed in the literature are either very specific or suffer from exponentially rising computational costs in the number of dimensions. We propose an extension that is very general and easily implemented, and does not suffer from the curse of dimensionality. Monte Carlo experiments for the mixed logit model indicate the superior performance of the proposed method over simulation techniques.     

A polyhedral approximation approach to concave numerical dynamic programming

This paper introduces a numerical method for solving concave continuous state dynamic programming problems which is based on a pair of polyhedral approximations of concave functions. The method is globally convergent and produces computable upper and lower bounds on the value function which can in theory be made arbitrarily tight. This is true regardless of the pattern of binding constraints, the smoothness of model primitives, and the dimensionality and rectangularity of the state space. We illustrate the method's performance using an optimal firm management problem subject to credit constraints and partial investment irreversibilities.     

Stability and efficiency from a Neo-Keynesian viewpoint

This paper raises once more the Keynesian challenge of the classical doctrine that an unguided market economy has a natural tendency towards optimal employment of resources. By means of a simple macromodel, we show that if quantity expectations are incorporated into the Walrasian model, then it is no longer generally true that the ‘invisible hand’ leads the economy to Walrasian equilibrium. Instead, it may lead the economy to a kind of Keynesian equilibrium in which the firms' sales expectations constitute a binding constraint on production. Moreover, while Pareto optimum is unstable and hence unattainable in our model, a ‘second-best’ optimum among stable equilibria exists and requires a public sector. Accordingly, a trade-off between efficiency and other policy aims occurs only at tax rates above the positive tax rate in optimum     

从顾客角度解析体验营销

目前,一种新的消费需求--体验需求,正在引起越来越多的企业关注.逐渐意识到要以顾客为导向的企业也更加注重这一体现顾客消费形式的需求,于是,体验营销破壳而出,营销也将随之步入体验营销时代.     

Overflow traffic from the viewpoint of renewal theory

In this paper some known formulae concerning overflow traffic have been derived in a simpler way than is generally done in literature, i.e. by using simple results obtained from elementary renewal theory.
After the model has been introduced, the distribution of intervals between overflows is calculated by means of a recurrence relation. A generalization of Erlang's formula for the call congestion follows almost immediately. The last section the special case of Poisson input is discussed.     

以和谐管理的视角看企业高层团队整合

经过改革开放20多年的发展,我国企业取得了长足的进步,为国家的经济建设做出了巨大的贡献.但是在进入新世纪以后,众多的企业在寻求进一步发展时,长期困扰企业家们的一个难题是企业高层人才缺乏和企业高层管理混乱的现实日益突出,使企业的发展受到了重大影响.企业家们不断地进行改革尝试,建立新的产权制度,引入职业经理人管理,实行股票期权,不断完善公司治理结构,但收效都不明显.究其原因在于没有从根本上建立企业高层"团队管理"的体制,缺乏以系统观点对高层成员进行"团队整合"的动力和方法,只是一味地引入西方所谓科学的管理手段而没有将中国传统文化融入其中.为此,有必要将"和谐管理"理论引入企业高层团队整合工作中,以和谐管理的视角来研究中国企业高层团队整合的特点与模式.     

Performance indicator evaluation for a cloud computing system from QoS viewpoint

With the development of information technology, the cloud computing system (CCS) has become a new paradigm for the business and clients. The system supervisor has to guarantee the CCS keeps a good quality of service (QoS) to satisfy the clients’ requirements. The maintenance action is thus necessary when the CCS falls to a specific state such that it cannot afford enough capacity to meet demand d. In order to measure the service level of a CCS, this paper constructs a network model and proposes a key performance indicator (KPI), where the KPI is utilized to evaluate the probability that the demand can be satisfied under both transmission time and maintenance budget constraints. A method to derive the interval estimation for the KPI is developed. The system supervisor can conduct the sensitive analysis to improve/investigate the most important part in a large CCS afterwards.     

An evaluation of residential area improvement strategies from the residents' viewpoint

This paper describes the application of several attitudinal evaluation techniques to evaluation of alternative street improvement strategies in a Melbourne suburb. Measures of individual strength of preference for particular strategy consequences are derived and aggregated to a total impact index, using explicit social choice rules. It is concluded that attitudinal techniques can play a useful role in evaluation where non-market consequences are important and behavioural evaluations are not available.     

从内因与外因的辩证关系看中国股市如何走出困境

影响股市规范化的因素很多,然而什么是其最根本的因素呢?本文从内因与外因的辨证关系的角度,分析了影响我国股市的深层次原因,认为建立一只高素质的投资队伍才是中国股市脱困的根本出路.     

中国城市化滞后根源新论

目前 ,很多人认为城乡户籍制度、重工业化战略和城市建设不力是中国城市化滞后的主要原因。实际上 ,这只是中国城市化滞后的现象和结果 ,其根源在于推动中国城市化进程的根本动力———工业结构处于世界产业体系中下游 ,城市化进程缺乏强大的经济基础 ;城镇流动人口经济收入较低 ,不能跨越城市化最低门槛 ,完成城市化的彻底转变 ;作为城镇人口就业的主要渠道———服务业———达不到人口城市化起跑的经济、人口的临界点。这三点决定了中国城市化滞后现象必将长期存在 ,而合理加速城市化进程的重点是确定有希望城市化的流动人口阶层 ,让这部分人口先城市化     

Hölder continuity of the policy function approximation in the value function approximation

We show that given a value function approximation V of a strongly concave stochastic dynamic programming problem (SDDP), the associated policy function approximation is Hölder continuous in V.     

Quasi-isotonic regression and stochastic approximation

Summary Mukerjee’s stochastic approximation procedure on a lattice is modified: at each stage of the procedure, a sample quasi-isotonic regression is calculated instead of the isotonic one, the former being defined as the least-squares fit of observations within the class of functions that are nonpositive on the left and nonnegative on the right of some point. An effective algorithm is given and a convergence theorem proven. A multidimensional version of the procedure is proposed, the question of its convergence being left open. Research supported by the Deutsche Forschungsgemeinschaft, SFB 72.     

Strategic pricing of differentiated consumer durables in a dynamic duopoly: A numerical analysis

Under different modes of competitive pricing behavior, profit-maximizing price trajectories are derived for durable products in a dynamic duopoly. Open-loop co-operative and non-cooperative pricing behavior is analyzed within a comprehensive model where sales of differentiated products are described by interlocked diffusion processes with realistic demand characteristics. Because of analytic complexity, the optimal trajectories implied by the control and differential-game problems are derived numerically across an extensive set of plausible market scenarios. Manipulation of initial market conditions enables derivation of optimal competitive pricing as a function of timing of entry.     

分岔隧道过渡段开挖稳定性三维数值分析

文章基于ABAQUS软件平台,采用数值分析方法对分岔隧道过渡段开挖稳定性进行了仿真分析,同时分析了开挖过程中围岩形变、应力及稳定性变化规律,进而探讨了设计施工方案的合理性。研究结果表明:采用设计推荐的正台阶法与多部开挖法相结合的新奥法施工工法,洞室稳定性和支护结构安全性能够满足安全施工要求。研究结果能为依托工程和同类工程的顺利施工提供有益参考。     

强风化砂质页岩隧道施工数值模拟与分析

基于隧道工程的特殊性,针对软弱围岩条件下设计和施工的关键技术研究尚不够成熟完善,各工程采用的支护参数等关键性指标差异也比较大。文章以在建的砂子坡隧道为研究对象,利用FLAC3D有限差分软件建立了浅埋偏压隧道强风化砂质页岩段的数值计算模型,分析了隧道开挖支护状态下围岩应力场、位移场的变化特征和支护结构的受力特点,得出了一些支护参数,探讨了隧道开挖期间支护结构的适用性,为实际相关工程设计和施工提供有益参考。