182 research outputs found
"Asymmetric Market Shares, Advertising, and Pricing: Equilibrium with an Information Gatekeeper"
We analyze the impact of market share on advertising and pricing decisions by firms that sell to loyal, non-shopping customers and can advertise to shoppers through an information intermediary or "gatekeeper." In equilibrium the firm with the smaller loyal market advertises more aggressively but prices less competitively than the firm with the larger loyal market, and there is no equilibrium in which both firms advertise with probability 1. The results differ significantly from earlier literature which assumes all prices are revealed to shoppers and finds that the firm with the smaller loyal market adopts a more competitive pricing strategy. The predictions of the model are consistent with advertising and pricing behavior observed on price comparison websites such as Shopper.com.online markets, E-commerce, market share, information gatekeeper, equilibrium price dispersion, advertising
Design of a compact, dexterous robot hand with remotely located actuators and sensors
Abstract-In this work, we report on our progress in the development of a new anthropomorphic robot hand at the University of Malta. Following a brief overview of the work carried out in our laboratory so far, we discuss in some detail and through a fresh perspective a number of important lessons that can be learned from the human hand, and that can be very useful in the development of an artificial hand that can ultimately match the human counterpart in the execution of many tasks. We present a new design for a robot hand with joint position and grasping force sensing, based on the specific approaches brought up in this discussion, and targeted to reproduce many of the capabilities of the human hand. In particular, all of the actuation and sensing devices of the hand are located remotely from the device, therefore facilitating the development of a compact and lightweight hand design. A prototype of the new hand has been constructed and is presented herein. Finally, we present the initial results of our analysis to demonstrate how the magnitude and location of grasping forces can be inferred from the sensor readings
Towards practical guidelines for conversion from fixed to reconfigurable manufacturing automation systems
It is generally considered that economic feasibility of a reconfigurable manufacturing system is only attainable if the system is defined to be reconfigurable at the outset of its design. In this work we consider the potential exception to this perception, in the context of a common industrial scenario where a specialized and expensive manufacturing machine or system will otherwise be rendered useless due to loss of business of the particular product being manufactured. Specific guidelines to convert from a fixed to a reconfigurable system are proposed, and evaluated through a case study. It is shown that under certain conditions, reconfigurable manufacturing systems may be economically feasible even if they are developed through the modification of pre-existing dedicated systems.peer-reviewe
Dexterous actuation
Methods that have been developed for actuation system evaluation are normally generic, and primarily intended to facilitate actuator selection. Here, we address specifically those engineering devices that exhibit multiple-degree-of-freedom motions under space and weight constraints, and focus on the evaluation of the total actuation solution. We suggest a new measure that we provisionally call âActuation Dexterityâ, which interrogates the effectiveness of this total solution and serves as a design support tool. The new concept is developed in the context of artificial hands, and the approach is based on the review and analysis of thirty-six different artificial hand projects described in the literature. We have identified forty-eight unique evaluation criteria that are relevant to the actuation of devices of this type, and have devised a scoring method that permits the quantification of the actuation dexterity of a given device. We have tested this approach by evaluating and quantifying the actuation dexterity of five different artificial hands from the literature. Finally, we discuss the implications of this approach to the design process, and the portability of the approach between different device types.peer-reviewe
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Teleneurology clinics for polyneuropathy: a pilot study.
INTRODUCTION:Polyneuropathy (PN) is a common condition with significant morbidity. We developed tele-polyneuropathy (tele-PN) clinics to improve access to neurology and increase guideline-concordant PN care. This article describes the mixed-methods evaluation of pilot tele-PN clinics at three community sites within the Greater Los Angeles VA Healthcare System. METHODS:For the first 25 patients (48 scheduled visits), we recorded the duration of the tele-PN visit and exam; the performance on three guideline-concordant care indicators (PN screening labs, opiate reduction, physical therapy for falls); and patient-satisfaction scores. We elicited comments about the tele-PN clinic from patients and the clinical team. We combined descriptive statistics with qualitative themes to determine the feasibility and acceptability of the tele-PN clinics. RESULTS:The average tele-PN encounter and exam times were 28.5 and 9.1 min, respectively. PN screening lab completion increased from 80 to 100%. Opiate freedom improved from 68 to 88%. Physical therapy for patients with recent falls increased from 58 to 100%. The tele-PN clinic was preferred for follow-up over in-person clinics in 86% of cases. Convenience was paramount to the clinic's success, saving an average of 231 min per patient in round-trip travel. The medical team's caring and collaborative spirit received high praise. While the clinic's efficiency was equal or superior to in-person care, the limited treatment options for PN and the small clinical exam space are areas for improvement. CONCLUSION:In this pilot, we were able to efficiently see and examine patients remotely, promote guideline-concordant PN care, and provide a high-satisfaction encounter
Stabilization of the Perovskite Phase of Formamidinium Lead Triiodide by Methylammonium, Cs, and/or Rb Doping
In this work we perform a computational study comparing the influence of monovalent cation substitution by methylammonium (MA(+)), cesium (Cs+), and rubidium (Rb+) on the properties of formamidinium lead triiodide (FAPbI(3))based perovskites. The relative stability of the desired, photoactive perovskite alpha phase ("black phase") and the nonphotoactive, nonperovskite delta phase ("yellow phase") is studied as a function of dopant nature, concentration and temperature. Cs+ and Rb+ are shown to be more efficient in the stabilization of the perovskite alpha phase than MA(+). Furthermore, varying the dopant concentration allows changing the relative stability at different temperatures, in particular stabilizing the alpha phase already at 200 K. Upon Cs+ or Rb+ doping, the corresponding onset of the optical spectrum is blue-shifted by 0.1-0.2 eV with respect to pure FAPbI(3
Quasi-dynamic analysis, design optimization, and evaluation of a two-finger underactuated hand
Underactuated hands are able to achieve shape adaptation to conformally grasp a wide variety of objects, while keeping low undesirable hand attributes such as weight, size, complexity and cost. The available analytical and simulation studies of planar underactuated hands normally assume quasi-static conditions and a fixed object. In the present paper, a new quasi-dynamic analysis of the grasping process in the horizontal plane by a planar, two-finger, four-joint underactuated hand is presented. The study considers object movement during the grasping process, and also contact friction with a surface that supports the object. An extensive and versatile simulation program, based on the analysis, is developed to investigate the effects of various parameters of hand and object on the grasping process. A prototype hand has been developed and the simulation results are validated experimentally. An extensive and detailed study and optimization exercise is carried out using the developed simulation tool. Specifically, the study concerns a manipulative grasping process that moves the object to the hand centerline during the process. Important new findings on the influence of link dimensions, link angular speeds, friction with the supporting surface, object mass and object size on the grasping performance of the hand in this scenario are presented. The results are used to establish new design guidelines for the hand. In particular, the results indicate that in the case where there is limited information on the size and precise initial location of the object to be grasped, the optimal hand design would involve inner to outer phalange size ratios of approximately 3:1, and inner phalange joints that are very close to each other.peer-reviewe
Impact of a social marketing intervention on general practitionersâ antibiotic prescribing practices for acute respiratory tract complaints in Malta
Introduction: Antibiotics are commonly prescribed in primary care for acute respiratory tract
complaints (aRTCs), often inappropriately. Social marketing interventions could improve prescribing
in such settings. We evaluate the impact of a social marketing intervention on general practitionersâ
(GPsâ) antibiotic prescribing for aRTCs in Malta.Methods: Changes in GPsâ antibiotic prescribing
were monitored over two surveillance periods between 2015 and 2018. Primary outcome: change
in antibiotic prescription for aRTCs. Secondary outcomes: change in antibiotic prescription: (i) for
immediate use, (ii) for delayed antibiotic prescription, (iii) by diagnosis, and (iv) by antibiotic class.
Data were analysed using clustered analysis and interrupted time series analysis (ITSA).Results:
Of 33 participating GPs, 18 successfully completed the study. Although clustered analyses showed
a significant 3% decrease in overall antibiotic prescription (p = 0.024), ITSA showed no significant
change overall (p = 0.264). Antibiotic prescription decreased significantly for the common cold
(p < 0.001), otitis media (p = 0.044), and sinusitis (p = 0.004), but increased for pharyngitis (p = 0.015).Conclusions: The intervention resulted in modest improvements in GPsâ antibiotic prescribing. A more
top-down approach will likely be required for future initiatives to be successful in this setting,
focusing on diagnostic and prescribing support like rapid diagnostic testing, prescribing guidelines,
and standardised delayed antibiotic prescriptions.peer-reviewe
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