The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

Teams, Firms and the Evolution of Profit Seeking Behavior

Even as advances in information theory over the last quarter century have cast increasing doubt on the proposition that firms successfully maximize profits, the objective of profit maximization continues to be an axiomatic feature of the neoclassical theory of the firm. This paper attempts to improve our understanding firms by treating the objective function as an open question. Specifically, an ontogenetic thought experiment is undertaken to address the question of what differentiates production teams from firms by asking why team members would sell their control rights to a principal, thereby transforming the team into a firm. What results is an account of the emergence of the objective of profit seeking. Profit seeking emerges endogenously as a more fit alternative than the objective of value maximization, which is less capable of coping with uncertainty through purposive adaptation.     

Optimization of Harvesting Return from Age-Structured Population

Synopsis Maximization of the net profit from harvesting in a one-species age-structured population is analyzed. One of the control functions is the age of harvested individuals. The constructed mathematical model is similar to vintage capital models used in economics for optimal capital replacement. The optimization technique developed by authors for the capital replacement is disseminated to the formulated problem. A qualitative analysis of the problem is provided and the interpretation of results is given. Such economic topics as a zero-investment period, optimal balanced growth, and turnpike properties are discussed.     

Efficiency measurement with multiple outputs and multiple inputs

This paper discusses modeling technical and allocative inefficiencies in both cost minimizing and profit maximizing frameworks with special emphasis on multiple inputs and multiple outputs. Both primal and dual models are considered for this purpose. In the primal approach we use a separable output and input function (the constant elasticity of transformation output function and Cobb-Douglas input function). The dual models assume translog cost or profit functions. Technical inefficiency is assumed to be random in the cross-sectional models, and fixed firm-specific parameter in the panel data models. Allocative inefficiencies are always treated as input-specific parameters. We derive exact relations linking technical inefficiency and allocative inefficiencies to cost and profit when the underlying technology is represented by a flexible functional form such as the translog. It is shown that appending a one-sided homoscedastic error term to model technical inefficiency, or neglecting technical inefficiency altogether in a translog profit tunciton results in model misspecification and inconsistent parameter estimates.     

Optimal portfolio choice in the bond market

We consider the Merton problem of optimal portfolio choice when the traded instruments are the set of zero-coupon bonds. Working within a Markovian Heath–Jarrow–Morton model of the interest rate term structure driven by an infinite-dimensional Wiener process, we give sufficient conditions for the existence and uniqueness of an optimal trading strategy. When there is uniqueness, we provide a characterization of the optimal portfolio as a sum of mutual funds. Furthermore, we show that a Gauss–Markov random field model proposed by Kennedy [Math. Financ. 4, 247–258(1994)] can be treated in this framework, and explicitly calculate the optimal portfolio. We show that the optimal portfolio in this case can be identified with the discontinuities of a certain function of the market parameters.     

The need for an alternative to shareholder value creation? The Ethomed student experience

This article aims to highlight the need for a radical break with the methodological individualism that dominates the fields of economics and management, especially finance. It advocates the need to try to understand the issues and methods that are required to coordinate economic action in order to meet social needs.The article questions methodological individualism and the dominant role played by shareholders. Is it possible to promote social welfare simply by considering it to be a result of a shareholder value maximization point of view? If not, this implies not only understanding fully the challenges that we face but also being innovative regarding the way in which we coordinate the actions that are necessary to meet these challenges head on, and perhaps promoting another character as a substitute for the shareholder.     

Random regret minimization for consumer choice modeling: Assessment of empirical evidence

This paper introduces to the field of marketing a regret-based discrete choice model for the analysis of multi-attribute consumer choices from multinomial choice sets. This random regret minimization (RRM) model, which has recently been introduced in the field of transport, forms a regret-based counterpart of the canonical random utility maximization (RUM) paradigm. This paper assesses empirical results based on 43 comparisons reported in peer-reviewed journal articles and book chapters, with the aim of finding out to what extent, when, and how RRM can form a viable addition to the consumer choice modeler's toolkit. The paper shows that RRM and hybrid RRM–RUM models outperform RUM counterparts in a majority of cases, in terms of model fit and predictive ability. Although differences in performance are quite small, the two paradigms often result in markedly different managerial implications due to considerable differences in, for example, market share forecasts.     

Climatic Factors as Determinants of International Migration

We examine natural disasters and long‐run climatic factors as potential determinants of international migration, implementing a panel dataset of bilateral migration flows from 1960 to 2000. We find no direct effect of long‐run climatic factors on international migration across our entire sample. These results are robust when conditioning on origin‐country characteristics, when considering migrants returning home, and when accounting for the potential endogeneity of migrant networks. Rather, we find evidence of indirect effects of environmental factors operating through wages. We find that epidemics and miscellaneous incidents spur international migration, and there is strong evidence that natural disasters beget greater flows of migrants to urban environs.     

Crime prediction by data-driven Green’s function method

We develop an algorithm that forecasts cascading events, by employing a Green’s function scheme on the basis of the self-exciting point process model. This method is applied to open data of 10 types of crimes happened in Chicago. It shows a good prediction accuracy superior to or comparable to the standard methods which are the expectation–maximization method and prospective hotspot maps method. We find a cascade influence of the crimes that has a long-time, logarithmic tail; this result is consistent with an earlier study on burglaries. This long-tail feature cannot be reproduced by the other standard methods. In addition, a merit of the Green’s function method is the low computational cost in the case of high density of events and/or large amount of the training data.     

基于古诺模型的四种市场的社会福利

市场根据垄断程度的不同。可以分为完全竞争、垄断竞争、寡头垄断和完全垄断市场四种类型。基于古诺模型，用博弈论方法研究n个厂商市场情形的总产量、价格、总收益和消费者剩余并把它们归纳为统一的公式。从四种市场情形总产量和价格的特点推出其供给曲线的形状，进而比较其社会福利的状况。研究结果表明，随着垄断性的加强，市场的社会福利会越来越劣，完全竞争市场的社会福利最好，垄断竞争市场次之，寡头垄断市场更次，完全垄断市场的社会福利最差。