Non-convexities and the gains from concealing defenses from committed terrorists

How should countries defend against committed terrorists who attack until defeated? We identify a fundamental non-convexity—one only needs to defeat the terrorist once. Consequently, provided a country values targets similarly, it should conceal defenses and allocate defense resources randomly.     

The devil in the details: Non-convexities in ecosystem service provision

Standard economic theory is built on key assumptions regarding concavity and convexity, particular with respect to the production possibility frontier. Non-convexity is readily demonstrated using a two species conventional model. Now that ecosystem services are growing in prominence it is important to confirm that typical natural resource production relations obey these conditions. If not, innocently prescribing price or allocation policies can lead to a minimum rather than a maximum or to wrong equilibrium solutions in general. This is a particular danger in decentralized pricing systems.     

Biology as a Source of Non-convexities in Ecological Production Functions

Generating ecological production functions, including harvest yield functions, is a high priority research area. Most yield functions used in economics and ecology rely on convexity properties of species growth functions, but convexity is shown here to depend on whether realistic biology is incorporated. Optimizing behavior by individual organisms is connected with species population dynamics in order to derive growth functions in a general equilibrium ecosystem model. Non convexities are shown to be an inherent property of the growth functions owing to familiar biological processes including predator-prey and competitive relations, predator satiation and prey substitution. The growth functions generate yield functions that are problematic for management, because they exhibit kinked average revenue curves, discontinuous marginal revenue curves, and knife edge optimum effort levels where a small increase above the optimum effort can rapidly deplete the stock. These phenomena can be explained entirely by the underlying biological processes.     

Optimal control problems from second-order difference equations

We examine solutions x?l_∞(Rⁿ) of the equations $\text{F}{}_{\mathrm{t}}\text{(}\text{x}{}_{\mathrm{t?1}}\text{,}\text{x}{}_{\mathrm{t}}\text{,}\text{x}{}_{\mathrm{t+1}}\text{) = 0}$ and derive conditions for the existence of objective functions G_t so that $\text{x}$ solves max_x?l∞ΣG_t(x_t, x_t+1). We specialize the conditions to time autonomous equations and apply them to a competitive industry in temporary equilibrium. The objective function in the example is of the cost-benefit form: consumer surplus minus opportunity cost of labor minus industry-wide cost of investment.     

Non-convexities in the adjustment of different capital inputs: A firm-level investigation

Recent developments in investment research have highlighted the importance of non-convexities and irreversibilities in firms’ adjustment of quasi-fixed inputs. Aggregation across capital goods may smooth out the discontinuities associated with the adjustment of individual assets. Lack of suitable data is one of the reasons why empirical work has typically relied on the assumption of capital homogeneity. In this paper we exploit a data set of 1539 Italian firms which allows us to disaggregate capital into equipment and structures, and purchases and sales of assets. We construct measures of fundamental Q to capture investment opportunities associated with each asset. We uncover the pattern of dynamic adjustment by using non-parametric techniques to relate each individual investment to its own fundamental Q.     

基于内控角度探讨公立医院预算管理存在的问题和对策

在当今竞争激烈的市场环境下,公立医院既要履行医疗卫生事业的公共服务职能,也要推动综合管理和经济建设发展,预算管理作为内部控制的重要组成部分,逐步得到重视和完善。新政府会计制度正式实施后,对公立医院的财务预算管理和内部控制提出了更高更全面的要求,医院通过强化预算管理,规范资金管控、降低运行成本,是稳定运营和持续发展的关键。本文从内控角度出发,探讨公立医院在预算管理工作中存在的问题,并提出优化对策。     

Enterprise reform in China: agency problems and political control

The past reforms of state-owned enterprises in China delegated many effective control rights to managers while maintaining ultimate control rights for the Party and government. The result is that either the agency costs are high because managers lack accountability or the political costs are high because the government causes political interference. Reform of state-owned enterprises in China should aim at reducing both political and agency costs, which can be done through depoliticization, effective corporate governance, and deserialization. In particular, China needs an ownership transformation with a combination of privatization, denationalization, and pluralization; a state assets management system to limit political influence from the government; and corporatization to establish effective corporate governance which may take a variety of forms.     

Politician control, agency problems and ownership reform

Using data from a recent national survey on the ownership reform of state‐owned enterprises in China, we study the effects of reducing politician control and agency problems on a number of reform outcomes. Taking into account the endogenous nature of the reform, we find that these outcome measures of the reform's success are positively affected by the lessening of politician control through increasing the firm's flexibility in labour deployment and by the mitigation of agency costs through the introduction of more effective corporate governance mechanisms such as one‐share one‐vote and shareholding‐based board structure composition. Ownership structure also matters: relative to shareholding by the state, foreign ownership has a positive effect on reform outcomes; individual (mostly employee) shareholding has a negative or insignificant effect. Somewhat surprisingly, operating autonomy (excluding labour deployment flexibility) has a negative effect on firm performance, suggesting serious agency problems in the reformed enterprises.     

国有企业内部控制的问题及对策研究

制造业是我国市场经济体系的重要组成部分,自改革开放以来,我国制造业发展迅速,现如今已成为世界第一制造大国,在500多种工业产品生产中,我国有200多种产量位居世界第一,对于我国经济增长的贡献率较高,制造业是一个国家生产力水平的体现,在我国的国民生产总值中占据较大比例,重视制造业的发展有助于提升我国的整体经济水平。在经济新常态形势下,随着研发、生产技术的不断进步,制造行业的竞争愈加激烈,同时也对制造行业内部管理提出了更高的要求。国有制造企业要提升市场竞争力,一方面需要依赖于技术创新,优化内部产品结构,另一方面需要重视强化内控管理,将内控思想贯穿于企业管理的方方面面,以实现企业的精细化管理。国有制造企业通过加强内控建设,完善内控制度体系,可以从内控环境、控制活动、风险防范、强化监督等四个方面对企业的管理机制进行优化、完善,进一步提升企业的管理水平,这对于现代企业的管理至关重要。通过构建科学的内部控制体系,可以保证国有企业经营活动的效益性、财务报告的真实性以及法律法规的遵循性,为国有企业的长远发展保驾护航。下文就国有企业内部控制中存在的问题进行探析,并提出相应的优化对策。     

On the convexity of the value function in Bayesian optimal control problems

Summary I study the question on the convexity of the value function and Blackwell (1951)'s Theorem and relate this to the uniqueness of optimal policies. The main results will conclude that strict convexity and a strict inequality in Blackwell's Theorem will hold if and only if from different priors different optimal actions may be chosen.Financial support from the C. V. Starr Center and the Research Challenge Fund at New York University is gratefully acknowledged. I thank Professor Tara Vishwanathan whose questioning resulted in this paper.     

Sufficient conditions in free final time optimal control problems. A comment

By an application of sufficient conditions, assume that an optimal pair (χ_τ(·), u_τ(·)) and an adjoint function p_τ(·) were found in the control problem in question with the final time τ fixed but arbitrary. Then a sufficient condition for one of these pairs, say , to be optimal in the corresponding free final time problem is that the Hamiltonian, with (χ_τ(t), u_τ(τ?), p_τ(τ), τ) inserted, is nonnegative (nonpositive) to the left (right) of $\text{τ}{}^1$.     

中小企业内部控制存在的问题及对策研究

近年来我国中小企业得到了迅速发展,在国民经济中占有越来越重要的地位。目前我国中小企业数量占据企业总量的绝大部分,成了维护社会稳定,促进就业增长,促进经济发展的关键力量。但是中小企业在管理过程中还存在许多问题,内部控制作为现代企业管理的重要组成部分,对于防范企业风险有着重要的作用,因此中小企业需要加强内部控制制度建设。本文以中小企业内部控制为研究对象,分析了中小企业的特点与内部控制理论,并根据中小企业内部控制的现状及问题提出了问题存在的原因,就中小企业特点针对内部控制建设提出了有效性建议,具有理论意义与现实意义。     

三峡地区退耕还林存在的问题

三峡地区主要是指重庆至宜昌一线所涉及的地理环境相类似的所有行政区划,包括重庆直辖市和湖北省的宜昌市、恩施土家族苗族自治州、神农架林区,国土面积大约为14万平方公里,人口约为4090万。改革开放以来,由于社会经济开发的不断加快,森林资源遭到严重破坏,水土流失加剧,导致三峡地区生态环境日趋恶化,阻碍了国民经济持续、稳健发展,严重影响了当地人民的生产生活及社会稳定。随着三峡工程的兴建和西部大开发战略的实施,三峡地区获得了空前的发展机遇,生态环境保护问题刻不容缓。实施退耕还林工程,对遏制森林资源锐减,减少水土流失,促进三峡…     

A simple proof of the monotonicity of the state trajectories in autonomous control problems

This paper deals with the question whether in optimal control problems with one state variable cyclical solutions and other nonmonotonicities can be optimal. It is shown that this can only occur if exogeneous shocks are brought into the model while for autonomous problems the state trajectory must always be monotonic. The proof also applies for nondifferentiable control problems as it does not use any regularity assumptions for the model functions.     

Additivity in bankruptcy problems and in allocation problems

We study the property of additivity in bankruptcy problems and in allocation problems. In bankruptcy problems we use this property to characterize the Talmudic rule proposed by Rabbi Ibn Ezra. Moreover we generalize this rule to every bankruptcy problem. Again, using additivity we characterize the rights egalitarian solution in allocation problems.     

Clever agents in adaptive learning

Saez-Marti and Weibull (J. Econom. Theory 86 (1999) 268) investigate the consequences of letting some agents play a myopic best reply to the myopic best reply in Young's (J. Econom. Theory 59 (1993) 145) bargaining model, which is how they introduce “cleverness” of players. I analyze such clever agents in general finite two-player games and show Young's (Individual Strategy and Social Structure, Princeton University Press, Princeton, NJ, 1998) prediction to be robust: adaptive learning with clever agents does select the same minimal curb set as in the absence of clever agents, if their population share is less than one. However, the long-run strategy distribution in such a curb set may vary with the share of clever agents.     

The signs of the co-state variables and sufficiency conditions in a class of optimal control problems

A class of optimal control problems is identified, for which co-state variables have definite signs and the Maximum Principle is sufficient for optimality. The restrictions defining this class of problems are given an economic interpretation.     

A state-contingent production approach to principal-agent problems with an application to point-source pollution control

Two basic representations of principal-agent relationships, the ‘state-space' and ‘parameterized distribution' formulations, have emerged. Although the state-space formulation appears more natural, analytical studies using this formulation have had limited success. This paper develops a state-space formulation of the moral-hazard problem using a general representation of production under uncertainty. A closed-form solution for the agency-cost problem is derived. Comparative-static results are deduced. Next we solve the principal's problem of selecting the optimal output given the agency-cost function. The analysis is applied to the problem of point-source pollution control.