scholarly journals Environmental incentives facing private information

Author(s):  
Franz Wirl

Abstract Environmental incentives are characterized by two distinct features: (1) a benefit-cost trade-off; and (2) private information about the trade-off. This suggests a degree of freedom of where to attach the private information, either to the benefit or the costs, as long as these choices imply the same behavior absent incentives (‘observation equivalent’). However, we show that different observation equivalent specifications can lead to different incentives. This is demonstrated for two cases: rainforest protection and contributions to a public good. Therefore, the choice of a private information parameter must be justified against observation equivalent alternatives.

Author(s):  
Qixin Zhu ◽  
Lei Xiong ◽  
Hongli Liu ◽  
Yonghong Zhu ◽  
Guoping Zhang

Background: The conventional method using one-degree-of-freedom (1DOF) controller for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between the dynamic performance and the robustness. Methods: In this paper, by using H∞ control theory, a novel robust two-degree-of-freedom (2DOF) controller has been proposed to improve the position control performance of PMSM servo system. Using robust control theory and 2DOF control theory, a H∞ robust position controller has been designed and discussed in detail. Results: The trade-off problem between the dynamic performance and robustness which exists in one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory. Then, through H∞ control theory, the design of robust position controller can be translated to H∞ robust standard design problem. Moreover, the control system with robust controller has been proved to be stable. Conclusion: Further simulation results demonstrate that compared with the conventional PID control, the designed control system has better robustness and attenuation to the disturbance of load impact.


Author(s):  
Guillaume Bouliane-Blais ◽  
Jean-Sébastien Plante

Soft technology is more and more present in robotics allowing safe interaction with humans, high dexterity in constrained environments, and safe manipulation of fragile or undefined objects. However, soft robotics is limited by a fundamental trade-off between available workspace and stiffness. Position feedback is also challenging as soft robots generally use deformable mechanisms instead of discrete joints. Here, the design of a soft four-degree-of-freedom tool positioner integrating a brake system and a soft sensor is proposed to address these issues. The design integrates molded air muscle actuators, granular jamming brakes, and Dielectric Elastomer Sensors (DES). The design is experimentally validated based on the requirements of a manipulator for liver cancer treatment, which is a representative application of soft robotics. The use of granular jamming mitigates the fundamental trade-off of soft robotics as it allows the manipulator to reach a large workspace (1500 cm3) while having the capacity to provide a high stiffness (up to19 times the initial stiffness). DES provides satisfactory position feedback, demonstrating a 0.69 mm accuracy that is lower than the 1 mm requirement. The proposed design using granular jamming and DES could greatly benefit human-safe and medical robotics.


2016 ◽  
Vol 2016 (4) ◽  
pp. 202-218 ◽  
Author(s):  
Ryan Henry

Abstract Private information retrieval (PIR) is a way for clients to query a remote database without the database holder learning the clients’ query terms or the responses they generate. Compelling applications for PIR are abound in the cryptographic and privacy research literature, yet existing PIR techniques are notoriously inefficient. Consequently, no such PIRbased application to date has seen real-world at-scale deployment. This paper proposes new “batch coding” techniques to help address PIR’s efficiency problem. The new techniques exploit the connection between ramp secret sharing schemes and efficient information-theoretically secure PIR (IT-PIR) protocols. This connection was previously observed by Henry, Huang, and Goldberg (NDSS 2013), who used ramp schemes to construct efficient “batch queries” with which clients can fetch several database records for the same cost as fetching a single record using a standard, non-batch query. The new techniques in this paper generalize and extend those of Henry et al. to construct “batch codes” with which clients can fetch several records for only a fraction the cost of fetching a single record using a standard non-batch query over an unencoded database. The batch codes are highly tuneable, providing a means to trade off (i) lower server-side computation cost, (ii) lower server-side storage cost, and/or (iii) lower uni- or bi-directional communication cost, in exchange for a comparatively modest decrease in resilience to Byzantine database servers.


2015 ◽  
Vol 45 (3) ◽  
pp. 601-623 ◽  
Author(s):  
Agathe Rouaix ◽  
Charles Figuières ◽  
Marc Willinger

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