And-Parallel Machines* Nachum Dershowitz and Naomi Lindenstrauss Department of Computer Science, The Hebrew University, Jerusalem 91904, Israel The deterministic Turing machine, though abstract, can still be seen as a model of a realistic computer. The same cannot be said for the nondeterministic Turing machine as a model of parallel computing. We introduce several abstract machines with fine-g...

Growing social concerns over the environmental externalities associated with business activities are pushing firms to identify activities that create economic value with less environmental impact and to become more eco-efficient. Over the past two decades, researchers have increasingly used frontier efficiency models to evaluate productive efficiency in the presence of undesirable outputs, such...

The paper develops tools for reconciling diverse measures which characterize the ®nancial performance of the Fortune 500 companies. The technology of data envelopment analysis (DEA) is employed to determine a multi-factor ®nancial performance model which inherently recognizes tradeo€s among various ®nancial measures. This study o€ers an alternative perspective and characterization on the perfor...

This article investigates the prerequisites for a global exploration strategy in an unknown environment on a virtual disaster site. Assume that a robot equipped with a laser range scanner can build a detailed map of a previous unknown environment. The remaining question is how to use this information on this map for further exploration. On a map several interesting locations can be present wher...

Stochastic nonparametric envelopment of data (StoNED) combines the virtues of data envelopment analysis (DEA) and stochastic frontier analysis (SFA) into a unified framework of frontier estimation. StoNED melds the nonparametric piece-wise linear DEA-type frontier with stochastic SFA-type inefficiency and noise terms. We show that the StoNED model can be estimated in the panel data setting in a...

We construct a model where the equilibrium organization of firms changes as an economy approaches the world technology frontier. In vertically integrated firms, owners (managers) have to spend time both on production and innovation activities, and this creates managerial overload, and discourages innovation. Outsourcing of some production activities mitigates the managerial overload, but create...

Although agenda of Water supply in sufficient quantity and standard quality is highlighted in India from last few years. But Yet Performance assessment and Efficiency evaluation of water supply services not in practice. However the analysis is confined to the realm of researchers and policy makers. The present paper spells inclusion of quality parameter in assessment of utilities through fronti...