The nature of the steady state in models of optimal growth under uncertainty

Summary. We study a one-sector stochastic optimal growth model with a representative agent. Utility is logarithmic and the production function is of the Cobb-Douglas form with capital exponent . Production is affected by a multiplicative shock taking one of two values with positive probabilities p and 1-p. It is well known that for this economy, optimal paths converge to a unique steady state, which is an invariant distribution. We are concerned with properties of this distribution. By using the theory of Iterated Function Systems, we are able to characterize such a distribution in terms of singularity versus absolute continuity as parameters and p change. We establish mutual singularity of the invariant distributions as p varies between 0 and 1 whenever . More delicate is the case . Singularity with respect to Lebesgue measure also appears for values such that . For and Peres and Solomyak (1998) have shown that the distribution is a.e. absolutely continuous. Characterization of the invariant distribution in the remaining cases is still an open question. The entire analysis is summarized through a bifurcation diagram, drawn in terms of pairs .Received: 9 April 2002, Revised: 29 October 2002, JEL Classification Numbers: C61, O41.Correspondence to: Tapan MitraThis research was partially supported by CNR (Italy) under the "Short-term mobility" program and by M.U.R.S.T. (Italy) National Group on "Nonlinear Dynamics and Stochastic Models in Economics and Finance" . We are indebted to Rabi Bhattacharya for providing us with the reference to Solomyak's (1995) paper. The present version has benefitted from comments by Mukul Majumdar and two anonymous referees.     

A baseline model of industry evolution

The paper analyses some general dynamic properties of industries characterized by heterogeneous firms and continuing stochastic entry.After a brief critical assessment of some significant drawbacks of recent contributions to modeling of stochastic industrial dynamics, we propose a novel analytical apparatus able to derive some generic properties of the underlying competition process combining persistent technological heterogeneity, differential growth of individual firms and turnover. The basic model, we suggest, is indeed applicable with proper modifications to a large class of evolutionary processes, well beyond industrial dynamics.JEL Classification: L11, O30, C60Support to this research by the International Institute for Applied Systems Analysis (IIASA), Austria; the Fujitsu Research Institute for Advanced Information (FRI), Japan; the Italian National Research Council (CNR), the Italian Ministry of Education, University and Research (MIUR, prot. 2002132413 003) and the Free University of Bozen Bolzano, Italy, is gratefully acknowledged. Comments by Andrea Bassanini, Francesca Chiaromonte, Steven Klepper, Uwe Cantner, Drew Fudenberg and the anonymous referees helped in shaping the paper to its present form. Mariele Berté provided the computer simulations of the model. The usual caveats apply.Correspondence to: G. Dosi     

Stochastic growth: asymptotic distributions

Summary. This note studies conditions under which sequences of state variables generated by discrete-time stochastic optimal accumulation models have law of large numbers and central limit properties. Productivity shocks with unbounded support are considered. Instead of restrictions on the support of the shock, an “average contraction” property is required on technology. Received: August 27, 2001; revised version: January 9, 2002 RID="*" ID="*"The author thanks John Creedy and Rabee Tourky for helpful comments, and the Economic Theory Center, University of Melbourne for financial support.     

Stochastic better-reply dynamics in finite games

In this paper, we analyze a model where individuals from finite populations are repeatedly drawn to play a finite game and in every period choose a weakly better reply to a sample distribution from a finite history of past play. For all finite games and sufficiently incomplete information, we prove convergence to minimal sets closed under better replies. This result complements previous findings in a deterministic continuous-time framework and implies convergence to strict Nash equilibria in many well-known classes of games.     

Marketing metrics' usage: Its predictors and implications for customer relationship management

This research aims to determine the conditions that foster use of marketing metrics in customer relationship management (CRM) and identify the organizational factors that strengthen/weaken the impact of usage of marketing metrics on CRM performance. Based on the customer value-based theory of the firm and the contingency perspective, a research framework was developed to shed light on the predictor roles of customer value-based organizational culture and processes in determining usage of marketing metrics, and foster an understanding of the moderating roles of marketing-supply chain conflict, and innovative value proposition on the marketing metric-performance relationships. Empirical evidence from a sample of 209 business firms confirmed the main effect that customer value-based organizational culture and processes support a firm's use of marketing metrics that in turn enhance its CRM performance. Notable moderating effects were also identified. Although marketing-supply chain conflict weakens the impact of marketing metrics usage in achieving superior CRM performance, innovative value proposition strengthens the conversion of marketing-metric-related knowledge into superior CRM performance.     

从企业价值链看电网企业“三集五大”集约化管理

用企业价值链理论分析了电网企业实施“三集五大”集约化管理的内在价值链模型,厘清了“三集”和“五大”2类活动的特性及其关系,分析了“三集五大”集约化管理的内涵和意义,从组织实施、业务整合、重点选择和信息化建设等方面提出了保障措施建议。     

Supply network capacity planning for semiconductor manufacturing with uncertain demand and correlation in demand considerations

A semiconductor supply network involves many expensive steps, which have to be executed to serve global markets. The complexity of global capacity planning combined with the large capital expenditures to increase factory capacity makes it important to incorporate optimization methodologies for cost reduction and long-term planning. The typical view of a semiconductor supply network consists of layers for wafer fab, sort, assembly, test and demand centers. We present a two-stage stochastic integer-programming formulation to model a semiconductor supply network. The model makes strategic capacity decisions, (i.e., build factories or outsource) while accounting for the uncertainties in demand for multiple products. We use the model not only to analyze how variability in demand affects the make/buy decisions but also to investigate how the correlation between demands of different products affects these strategic decisions. Finally, we demonstrate the value of incorporating demand uncertainty into a decision-making scheme.     

Economy size and performance: An efficiency analysis in the telecommunications sector

The existing empirical evidence on the relationship between economy size and performance has been inconclusive. This paper employs stochastic frontier analysis to estimate economic measures of efficiency for the telecommunications sectors of 139 economies and examine their relationship with economy size. Simultaneously, it controls for the effects of competition in telecommunications, privatization of state-owned providers, independent regulators, and the quality of political institutions on sector performance. The findings suggest that economy size has a positive but decreasing impact on sector performance. Small economies have an incentive to grow to improve sector performance, though larger size is not a sufficient condition for efficiency. Sector policy and the quality of polity may contribute significantly to sector performance.     

Sheltering network planning and management with a case in the Gulf Coast region

This paper studies sheltering network planning and operations for natural disaster preparedness and responses with a two-stage stochastic program. The preparedness phase decides the locations, capacities and resources of new Permanent Shelters. Under each disaster scenario, both evacuees and resources are distributed to shelters in the response phase. To address the computational burden, the L-shaped algorithm is applied to decompose the problem into the scenario level with linear programs. A case study for hurricanes in the Gulf Coast region of the US is conducted to demonstrate the implementation of the proposed model.     

Determining the optimal dimension of a work-in-process storage area

We study the problem of determining the optimal dimension of a work-in-process storage area in a two-line production system with delays and breakdowns. We propose a stochastic model and prove theoretical results that allow us to implement an exact algorithm for the solution of the model. We optimally solve a real instance and carry out a sensitivity analysis to evaluate if the optimal solution is stable when the initial data are perturbed.