Generic Connectivity-Based CGRA Mapping via Integer Linear Programming

Coarse-grained reconfigurable architectures (CGRAs) are programmable logic devices with large coarse-grained ALU-like logic blocks, and multi-bit datapath-style routing. CGRAs often have relatively restricted data routing networks, so they attract CAD mapping tools that use exact methods, such as Integer Linear Programming (ILP). However, tools that target general architectures must use large constraint systems to fully describe an architecture's flexibility, resulting in lengthy run-times. In this paper, we propose to derive connectivity information from an otherwise generic device model, and use this to create simpler ILPs, which we combine in an iterative schedule and retain most of the exactness of a fully-generic ILP approach. This new approach has a speed-up geometric mean of 5.88x when considering benchmarks that do not hit a time-limit of 7.5 hours on the fully-generic ILP, and 37.6x otherwise. This was measured using the set of benchmarks used to originally evaluate the fully-generic approach and several more benchmarks representing computation tasks, over three different CGRA architectures. All run-times of the new approach are less than 20 minutes, with 90th percentile time of 410 seconds. The proposed mapping techniques are integrated into, and evaluated using the open-source CGRA-ME architecture modelling and exploration framework.Comment: 8 pages of content; 8 figures; 3 tables; to appear in FCCM 2019; Uses the CGRA-ME framework at http://cgra-me.ece.utoronto.ca

evaluation of elliptical, glass fiber reinforced polymer, and stainless steel dowel bars in concrete pavements with consideration to subgrade resilient modulus

Jointed plain concrete pavements use dowel bars to transfer load across transverse joints. The job of the designer is to optimize the number, size, and location of the dowels in a given pavement. This research used data from two different construction locations. The first project evaluated the performance of standard 1.5 inch round and elliptical shaped dowel bars at different spacing intervals using full dowel baskets. The performance potential of standard 1.5 inch round and elliptical dowels placed in the wheel paths only was also evaluated on the same project. The second project compared corrosion resistant dowel bar (stainless steel and glass fiber reinforced polymer (GFRP) dowel bars) performance to round 1.5 inch epoxy-coated steel dowel bars. The stainless steel and GFRP bars are for possible use in environments where steel corrosion may be an issue. Performance data was measured on both projects in terms of deflections, using falling weight deflectometer (FWD) data collected biannually. Joint faulting data was collected over the five-year test period for both projects. Roughness data was collected for only the elliptical dowel bar project over the five-year test period. Resilient modulus values were found by triaxial testing of the pavement subgrade samples. Performance criteria graphed verses resilient modulus allowed for the comparison of different dowels as the subgrade resilient modulus changed. The elliptical dowel bar study indicated medium elliptical dowel bars at 12 inch or 15 inch spacing perform equally to the standard 1.5 inch round dowel bars at 12 inch spacing. The elliptical study also indicated the potential use of medium elliptical dowel bars in wheel paths only. The corrosion resistance study indicated stainless steel dowels spaced at eight inch intervals were the only dowels to outperform the 12 inch spaced round 1.5 inch epoxy-coated bars

Trust and Trustworthiness in Procurement Contracts with Retainage

When product quality is unverifiable by third parties, enforceable contracts that condition price upon quality are not feasible. If higher quality is also costly to deliver, moral hazard by sellers flourishes, particularly when procurement is via a competitive auction process. Retainage is a contractual mechanism that presents a solution to the third-party unverifiability problem, by setting aside a portion of the purchase price. After delivery, the buyer has sole discretion over the amount of retainage money that is released to the seller. While generally a feasible contract form to implement, retainage introduces a moral hazard for the buyer. We use laboratory experiments to investigate how and when retainage might be successfully used to facilitate trust and trustworthiness in procurement contracts. We observe that retainage induces a significant improvement in product quality when there are some trustworthy buyers in the population, consistent with a model of fair payment norms that we develop. This improvement is realized at the cost of increased buyer-seller profit inequalities. We also observe that at high levels of retainage, there is a welfare-decreasing market unraveling in which sellers do not bid on contracts. Our results imply that retainage incentives can mitigate the tension between competition and cooperation arising from reverse auctions, but only at appropriate levels of retainage

The Impact of the Covid-19 Pandemic on Economic Behaviours and Preferences: Experimental Evidence from Wuhan

We examine how the emergence of Covid-19 in Wuhan, and the ramifications of associated events, influence pro-sociality, trust and attitudes towards risk and ambiguity. We assess these influences using an experiment consisting of financially incentivized economic tasks. We establish causality via the comparison of a baseline sample collected pre-epidemic with five sampling waves starting from the imposition of a stringent lock- down in Wuhan and completed six weeks later. We find significant long-term increases - measured as the difference between the baseline and final wave average responses - in altruism, cooperation, trust and risk tolerance. Participants who remained in Wuhan during the lockdown exhibit lower trust and cooperation relative to other participants. We identify transitory effects from two events that permeated the public psyche. First, in the immediate aftermath of the Wuhan lockdown, there is a decrease in trust and an increase in ambiguity aversion. Second, the news of a high-profile whistleblower\u27s death also decreases trust while heightening risk aversion

Contingent Payments in Procurement Interactions - Experimental Evidence

A chief objective of creating competition among suppliers is the procurement of higher quality goods at lower prices. When procuring non-standard goods, it is often difficult to write a complete specification of desired quality in the contract. A moral hazard arises when this quality is costly and determined by the supplier ex post to contracting. In an effort to mitigate this moral hazard, we introduce a correlated contingent payment contract. This contract is awarded through competitive bidding. The winning supplier’s payment is, according to a fixed probability, either the amount of their bid or a quality contingent amount that depends on the bid and an exogenous norm for how a seller and buyer split social surplus. We show, both theoretically and experimentally, there is a “Goldilocks” region for high quality to emerge in which the probability of quality contingent payment is large enough to reward high quality provision, but not too large to induce overly aggressive bidding. This optimal implementation only relies upon preferences for maximizing one’s own profit and the rationality of backward induction. A surprising experimental result is that suppliers earned positive economic profits within this region. We estimate a structural model of bounded rationality to show that risk aversion can explain this result. These results have managerial implications for the design of contingent payments in contracts

The Nature of the Density Clump in the Fornax Dwarf Spheroidal Galaxy

We have imaged the recently discovered stellar overdensity located approximately one core radius from the center of the Fornax dwarf spheroidal galaxy using the Magellan Clay 6.5m telescope with the Magellan Instant Camera (MagIC). Superb seeing conditions allowed us to probe the stellar populations of this overdensity and of a control field within Fornax to a limiting magnitude of R=26. The color-magnitude diagram of the overdensity field is virtually identical to that of the control field with the exception of the presence of a population arising from a very short (less than 300 Myr in duration) burst of star formation 1.4 Gyr ago. Coleman et al. have argued that this overdensity might be related to a shell structure in Fornax that was created when Fornax captured a smaller galaxy. Our results are consistent with this model, but we argue that the metallicity of this young component favors a scenario in which the gas was part of Fornax itself.Comment: 24 pages including 8 figures and 3 tables. Accepted by Astronomical Journa

Crisis Leadership During the Great Recession of 2008

Understanding leadership characteristics, frameworks, components, and contexts that are beneficial to the guidance of organizational policy is useful for understanding the way in which leaders should act during a crisis. Recessions are common throughout economies; yet, many see recessions as crises. Due to the chaotic nature of economic recessions, leaders must work in conditions of uncertainty, complexity, and volatility. Therefore, using a qualitative phenomenological approach, an examination was conducted on leaders’ lived experiences of the Great Recession of 2008 to further understand the concept of crisis leadership. A discussion is included on the way in which leaders internalize and analyze the crisis and the characteristics and behaviors needed to sustain through the crisis. This research was conducted in 2013

SMOS Optical Thickness Changes in Response to the Growth and Development of Crops, Crop Management, and Weather

The Soil Moisture and Ocean Salinity (SMOS) remote sensing satellite was launched by the European Space Agency in 2009. The L-band brightness temperature observed by SMOS has been used to produce estimates of both soil moisture and τ, the optical thickness of the land surface. Although τ should theoretically be proportional to the amount of vegetation present within a SMOS pixel, several initial investigations have not been able to confirm this expected behavior. However, when the noise in the SMOS τ product is removed, τ in the U.S. Corn Belt, a region of extensive row-crop agriculture, has a distinct shape that mirrors the growth and development of crops. We find that the peak value of SMOS τ occurs at approximately 1000 °C day (base 10 °C) growing degree days after the mean planting date of maize (corn). We can explain this finding in the following way: τ is directly proportional to the water column density of vegetation; maize contributes the most to growing season changes in τ in the Corn Belt; and maize reaches its maximum water column density at its third reproductive stage of development, at about 1000 °C day growing degree days. Consequently, SMOS τ could be used to monitor the phenology of crops in the Corn Belt at a spatial resolution similar to a U.S. county and a temporal frequency on the order of days. We also examined the magnitude of the change in SMOS τ over the growing season and hypothesized it would be related to the amount of accumulated solar radiation, but found this not to be the case. On the other hand, the change in magnitude was smallest for the year in which the most precipitation fell. These findings are rational since SMOS τ at the satellite scale is in fact a function of both vegetation and soil surface roughness, and soil surface roughness is reduced by precipitation. To fully explain changes in SMOS τ in the Corn Belt it appears that it will be necessary to use in situ and remotely-sensed observations along with agro-ecosystem models to account for land management decisions made by farmers that affect changes in soil surface roughness and all of the relevant biophysical processes that affect the growth and development of crops

Enhancing free-living fall risk assessment: Contextualising mobility based IMU data

Fall risk assessment needs contemporary approaches based on habitual data. Currently, inertial measurement unit (IMU) based wearables are used to inform free-living spatio-temporal gait characteristics to inform mobility assessment. Typically, a fluctuation of those characteristics will infer an increased fall risk. However, current approaches with IMU’s remains limited as there are no contextual data to comprehensively determine if underlying mechanistic (intrinsic) or envi-ronmental (extrinsic) factors impact mobility and therefore fall risk. Here, a case study is used to explore and discuss how contemporary video-based wearables could be used to supplement arising mobility-based IMU gait data to better inform habitual fall risk assessment. A single stroke survivor was recruited, and he conducted a series of mobility tasks in a lab and beyond while wearing video-based glasses and a single IMU. The latter generated topical gait characteristics that were discussed according to current research practices. Although current IMU-based approaches are beginning to provide habitual data they remain limited. Given the plethora of extrinsic factors that may influence mobility-based gait there is a need to corroborate IMU’s with video data to comprehensively inform fall risk assessment. Use of artificial intelligence (AI) based computer vision approaches could drastically aid the processing of video data in a timely and ethical manner. Many off-the-shelf AI tools exist to aid this current need and provide a means to automate con-textual analysis to better inform mobility from IMU gait data for an individualized and con-temporary approach to habitual fall risk assessment