From selfish auctioning to incentivized marketing

Auction and market-based mechanisms are among the most popular methods for distributed task allocation in multi-robot systems. Most of these mechanisms were designed in a heuristic way and analysis of the quality of the resulting assignment solution is rare. This paper presents a new market-based multi-robot task allocation algorithm that produces optimal assignments. Rather than adopting a buyer’s “selfish” bidding perspective as in previous auction/market-based approaches, the proposed method approaches auctioning from a merchant’s point of view, producing a pricing policy that responds to cliques of customers and their preferences. The algorithm uses price escalation to clear a market of all its items, producing a state of equilibrium that satisfies both the merchant and customers. This effectively assigns all robots to their tasks. The proposed method can be used as a general assignment algorithm as it has a time complexity ( \(O(n^3 \text {lg} n)\) ) close to the fastest state-of-the-art algorithms ( \(O(n^3)\) ) but is extremely easy to implement. As in previous research, the economic model reflects the distributed nature of markets inherently: in this paper it leads directly to a decentralized method ideally suited for distributed multi-robot systems.     

British Intelligence and the Fear of a Soviet Attack on Allied Communications

This article considers British intelligence fears about a Soviet attack on Allied communications. It includes a reproduction of a 1959 assessment by the Joint Intelligence Committee focusing on the means of communication across the Atlantic, and the means by which the Soviet Union could interfere or intercept them.     

Automatic calibration of laser range finder positions for pedestrian tracking based on social group detections

Laser range finders (LRF’s) are non-invasive sensors which can be used for high-precision and anonymous tracking of pedestrians in social environments. Such sensor networks can be used in robotics to assist in navigation and human–robot interaction. Typically, multiple LRF’s are used together for such tasks, and the relative positions of these sensors must be precisely calibrated. We propose a technique for estimating relative LRF positions using observations of social groups in the pedestrian flow as keypoint features for determining coarse estimates of relative sensor offsets. The most likely offset is estimated using a generalized Hough transform and used to identify sets of possible shared observations of individual pedestrians between pairs of sensors. Outliers are rejected using the RANSAC technique, and the resulting shared observations from each sensor pair are combined into a constraint matrix for the sensor network, which is solved using least-squares minimization. Results show calibration accuracy of sensor positions within 34?mm and 0.51°, and an analysis of pedestrian data collected from ubiquitous networks in three public and commercial spaces shows that the proposed calibration technique enables pedestrian tracking within 11?cm accuracy.     

Composition Under Distributive Natural Transformations: Or,When Predicate Abstraction is Impossible

Journal of Logic, Language and Information - Natural language semanticists have often found it useful to assume that all expressions denote sets of values. The approach is most prominent in the...     

Buffer occupancy and link state opportunistic routing for wireless mesh networks

Wireless Networks - Providing a high level of Quality of Service is essential for future wireless networks. This article presents a new multihop wireless routing protocol that opportunistically...     

Viscoelastic properties of poly(butylene terephthalate)/poly(ethylene naphthalate) blends

Melt blends of poly(butylene terephalate) (PBT) and poly(ethylene naphthalate) (PEN) with 30 and 60 wt% PEN were prepared using a single screw extruder and an injection moulding machine. Stress relaxation tests for the specimens of PBT/PEN blends and the homopolymers were carried out using an Instron testing machine in an Instron environmental chamber. The Taguchi method of experimental design analysed how different levels of temperature, PEN content and initial stress affected the relaxation behaviour of PBT/PEN blends and homopolymers. From the response tables and analyses of main and interaction effects, it was shown that the most significant factor was temperature, followed by PEN content and then the initial stress. Consequently, high temperature, low PEN content and high initial stress speeded up stress relaxation rate of specimens. Interaction effects between factors were insignificant. To fit the relaxation curves of the PBT/PEN blends and the homopolymers at different temperatures, PEN contents and the initial stresses, four different equations were attempted with Matlab™, which determined the coefficients of these functions using the experimental data of stress change with time. The simulated curves from the most suitable function among them were shown using the calculated coefficients to predict the relaxation behaviour of PBT/PEN blends (50% PEN) at temperatures of 30 and 60°C with an initial stress of 7 MPa.     

Evaporative concentration of skimmed milk: Effect on casein micelle hydration,composition, and size

Understanding the effect of evaporative concentration on casein micelle composition is of high importance for milk processing. Alterations to the hydration, composition and size of casein micelles were investigated in skimmed milk evaporated to concentrations of 12–45% total solids content. The size of casein micelles was determined by dynamic light scattering, and the water content and composition determined by analysis of supernatants and pellets obtained by ultracentrifugation. The mass balance and hydration results showed that during the evaporation process, while micelles were dehydrated, water was removed preferentially from the serum. The amount of soluble casein and calcium in the serum decreased as a function of increasing solids content, indicating a shift of these components to the micelles. The formation of a small proportion of micelle aggregates at high concentrations appeared dependent on the time kept at these concentrations. Upon redilution with water, casein micelles were immediately rehydrated and aggregates were broken up in a matter of minutes. Soluble calcium and pH returned to their original state over a number of hours; however, only a small percentage of original soluble casein returned to the serum over the 5 h period investigated. These results showed that casein micelles are significantly affected by evaporative concentration and that the alterations are not completely and rapidly reversible.     

Infusible acrylic thermoplastic resins: Tailoring of chemorheological properties

Infusible liquid resins that polymerize into a thermoplastic are desirable for many applications. Similar to unsaturated and vinylester thermosetting systems, they consist of polymers dissolved in reactive monomer. This work presents a method to decrease cycle time by tuning the molecular weight and concentration of the predissolved polymer in the resin. Variation of these properties allows precise control of the viscosity which in turn controls the time at which peak exotherm is reached, the maximum temperature for a given part thickness, and cure time. Predictive models for the viscosity dependence on molecular weight, polymer concentration, shear rate, and temperature are developed. Two fiberglass panels are fabricated and tested; one with a lower molecular weight (M_w~30 kg mol⁻¹) poly(methyl methacrylate) dissolved in methyl methacrylate and the second with higher molecular weight (M_w~500 kg mol⁻¹) predissolved polymer in the resin. Mechanical properties are indistinguishable but the lower molecular weight panel cures up to three times faster. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48006.     

Carsharing and Car Ownership at the Building Scale

Problem, research strategy, and findings: A number of studies across the world have established the potential of carsharing to reduce vehicle ownership and parking demand at the citywide or neighborhood scale; however, few North American cities have formally adopted reduced minimum parking requirements for developments with carsharing services onsite (i.e., dedicated carshare vehicles). This reflects the lack of evidence regarding the impacts of carsharing on individual developments, as well as the implementation and enforcement challenges associated with adopting more flexible parking requirements.

This article investigates the case for developing and implementing a reduction in the parking requirements for residential buildings that provide dedicated carshare vehicles. We use surveys of residents of buildings with and without dedicated carshare vehicles in Toronto, Canada, to develop a regression model of vehicle ownership. This analysis suggests that the presence of dedicated carshare vehicles is associated with reduced vehicle ownership and parking demand at the building level. This is the first study, to the authors’ knowledge, that quantifies this relationship at the scale of individual developments.

Takeaway for practice: This article provides recommendations for developing a parking reduction ratio for carsharing that is compatible with existing parking requirements. It also considers approaches to promote the long-term financial viability of dedicated carshare vehicles. Overall, this study provides a starting point for those considering if and how to relax parking requirements for developments with access to carsharing services and illustrates some of the challenges with adopting flexible parking requirements.

Research support: The City of Toronto.