8,399 research outputs found

    Vote buying revisited: implications for receipt-freeness

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    In this paper, we analyse the concept of vote buying based on examples that try to stretch the meaning of the concept. Which ex- amples can still be called vote buying, and which cannot? We propose several dimensions that are relevant to qualifying an action as vote buy- ing or not. As a means of protection against vote buying and coercion, the concept of receipt-freeness has been proposed. We argue that, in or- der to protect against a larger set of vote buying activities, the concept of receipt-freeness should be interpreted probabilistically. We propose a general definition of probabilistic receipt-freeness by adapting existing definitions of probabilistic anonymity to voting

    Velocity dependence of joint friction in robotic manipulators with gear transmissions

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    This paper analyses the problem of modelling joint friction in robotic manipulators with gear transmissions at joint velocities varying from close to zero until their maximum appearing values. It is shown that commonly used friction models that incorporate Coulomb, (linear) viscous and Stribeck components are inadequate to describe the friction behaviour for the full velocity range. A new friction model is proposed that relies on insights from tribological models. The basic friction model of two lubricated discs in rolling-sliding contact is used to analyse viscous friction and friction caused by asperity contacts inside gears and roller bearings of robot joint transmissions. The analysis shows different viscous friction behaviour for gears and pre-stressed bearings. The sub-models describing the viscous friction and the friction due to the asperity contacts are combined into two friction models; one for gears and one for the pre-stressed roller bearings. In this way, a new friction model [1] is developed that accurately describes the friction behaviour in the sliding regime with a minimal and physically sound parametrisation. The model is linear in the parameters that are temperature dependent, which allows to estimate these parameters during the inertia parameter identification experiments. The model, in which the Coulomb friction effect has disappeared, has the same number of parameters as the commonly used Stribeck model [2]. The model parameters are identified experimentally on a St ¨aubli RX90 industrial robot

    Supporting telecom business processes by means of workflow management and federated databases

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    This report addresses the issues related to the use of workflow management\ud systems and federated databases to support business processes that operate on\ud large and heterogeneous collections of autonomous information systems. We\ud discuss how they can enhance the overall IT-architecture. Starting from the\ud OSCA architecture, we develop an architecture that includes workflow\ud management systems and federated databases. In this architecture, the notion of\ud information systems as a monolithic entity disappears. Instead, business\ud processes are supported directly by workflows that combine presentation\ud blocks, function blocks, and data blocks. We address the specific issues of\ud transaction management and change management in such an architecture

    Towards a quantitative concession-based classification method of negotiation strategies

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    In order to successfully reach an agreement in a negotiation, both parties rely on each other to make concessions. The willingness to concede also depends in large part on the opponent. A concession by the opponent may be reciprocated, but the negotiation process may also be frustrated if the opponent does not concede at all.This process of concession making is a central theme in many of the classic and current automated negotiation strategies. In this paper, we present a quantitative classification method of negotiation strategies that measures the willingness of an agent to concede against different types of opponents. The method is then applied to classify some well-known negotiating strategies, including the agents of ANAC 2010. It is shown that the technique makes it easy to identify the main characteristics of negotiation agents, and can be used to group negotiation strategies into categories with common negotiation characteristics. We also observe, among other things, that different kinds of opponents call for a different approach in making concession