How Constraints Affect Content: The Case of Twitter's Switch from 140 to 280 Characters

It is often said that constraints affect creative production, both in terms of form and quality. Online social media platforms frequently impose constraints on the content that users can produce, limiting the range of possible contributions. Do these restrictions tend to push creators towards producing more or less successful content? How do creators adapt their contributions to fit the limits imposed by social media platforms? To answer these questions, we conduct an observational study of a recent event: on November 7, 2017, Twitter changed the maximum allowable length of a tweet from 140 to 280 characters, thereby significantly altering its signature constraint. In the first study of this switch, we compare tweets with nearly or exactly 140 characters before the change to tweets of the same length posted after the change. This setup enables us to characterize how users alter their tweets to fit the constraint and how this affects their tweets' success. We find that in response to a length constraint, users write more tersely, use more abbreviations and contracted forms, and use fewer definite articles. Also, although in general tweet success increases with length, we find initial evidence that tweets made to fit the 140-character constraint tend to be more successful than similar-length tweets written when the constraint was removed, suggesting that the length constraint improved tweet quality.Comment: To appear in the Proceedings of AAAI ICWSM 201

Human information processing research in auditing A review and synthesis

https://egrove.olemiss.edu/dl_proceedings/1144/thumbnail.jp

On the Geometric Realisation of Equal Tempered Music

Since the time of Pythagoras (c.550BC), mathematicians interested in music have asked, “What governs the whole number ratios that emerge from derivations of the harmonic series?” Simon Stevin (1548-1620) devised a mathematical underlay (where a semitone equals 21/12) that gave rise to the equal temperament tuning system we still use today. Beyond this, the structure of formalised musical orderings have eluded many of us. Music theorists use the tools and techniques of their trade to peer into the higher-order musical structures that underpin musical harmony. These methods of investigating music theory and harmony are difficult to learn (and teach), as complex abstract thought is required to imagine the components of a phenomenon that cannot be seen. This paper outlines a method to understanding the mathematical underpinnings of the equal tempered tuning system. Using this method, musical structure can be quantitatively modelled as a series of harmonic elements at each pulse of musical time

Analysis of a PWM Resonant Buck Chopper for Use as a Ship Service Converter Module

The Navy's interest in implementing a DC Zonal Electric Distribution System (DC ZEDS) in the next generation of surface combatant has motivated considerable research work into dc-dc converters. The switching frequency of a hard-switched dc-dc converter is limited by the maximum admissible switching losses allowed by the switch, heat sink, and cooling process. Also, hard- switched converters contribute significant Electromagnetic Interference (EMI) concerns for the system. This study provides a background analysis into resonant converters which utilize zero-voltage-switching and zero-current-switching techniques to mitigate the aforementioned concerns and facilitate high-bandwidth control loops. In particular, one candidate circuit is identified which can be readily realized using existing hardware and a straightforward control. The report documents the modes of operation of the circuit, sets forth the governing differential equation and mode-transition conditions, examines an ACSL simulation representation of the circuit, formulates design criteria for component selection, identifies key fabrication nuances, and documents a PSpice simulation of the circuit. Both simulation models are used to explain the operating modes of the circuit, provide insight into parameter selection, and ultimately to design the proper control of the circuit.Prepared for: Naval Surface Warfare Center (NSWC) Annapolis Det.N00167-98-WR-80279Approved for public release; distribution is unlimited

Using and evaluating audit decision aids

https://egrove.olemiss.edu/dl_proceedings/1031/thumbnail.jp

The price, quality and distribution of mortgage payment protection insurance: a hedonic pricing approach

Mortgage payment protection insurance (hereafter MPPI) provides varying combinations of accident, sickness and unemployment insurance and is used to protect the mortgage payments of policyholders in the event of a fall in income. Despite alleviating housing market failures, this service has been heavily criticised for providing poor value for money and being associated with unhelpful sales techniques especially when sold jointly with a mortgage in the UK. Consequently, the Competition Commission (2009) ruled that after February 2011 MPPI should not be sold jointly with mortgage lending within seven days of the credit transaction. We examine whether this prohibition was justified and if the form of distribution, either jointly with the mortgage or independently influences the premium levels. This assessment uses a hedonic pricing approach with details and premiums of MPPI policies in 2010 and 2012. Despite the success in reducing MPPI premium levels, we conclude that the Competition Commission judgement has raised concerns as to mortgagee protection

The Effects of Glass Fiber Fillers On Epoxy Resin Performance

Premature failure of filtration members in biochemical processing is a costly issue for manufacturers. This research aims to determine whether or not the premature failure due to thermal fatigue in medical filtration devices can be mitigated by glass fiber addition. The study was conducted to identify the effects of e-glass fiber filler content in an epoxy matrix on the mechanical and thermal properties of the epoxy system. The epoxy was evaluated over a filler content of 0-50wt% in level increments of 12.5wt% and temperatures ranging from ambient to 160°C in increments of 15°C. Cylindrical and tensile bar specimens were prepared for each filler content level to evaluate the effect on thermal expansion, glass transition temperature and tensile properties. Caliper measurements of cylindrical specimens across the temperature range concluded that there is a significant inverse relationship between filler content and thermal expansion. Glass content did not present a significant effect on the glass transition temperatures which were measured though differential scanning calorimetry. Tensile testing of the samples found that the epoxy composite was stiffer at higher filler contents. These findings indicate that the addition of glass fibers may not serve as a viable method of increasing the filter production lifetime

Depletion potentials in highly size-asymmetric binary hard-sphere mixtures: Comparison of accurate simulation results with theory

We report a detailed study, using state-of-the-art simulation and theoretical methods, of the depletion potential between a pair of big hard spheres immersed in a reservoir of much smaller hard spheres, the size disparity being measured by the ratio of diameters q=\sigma_s/\sigma_b. Small particles are treated grand canonically, their influence being parameterized in terms of their packing fraction in the reservoir, \eta_s^r. Two specialized Monte Carlo simulation schemes --the geometrical cluster algorithm, and staged particle insertion-- are deployed to obtain accurate depletion potentials for a number of combinations of q\leq 0.1 and \eta_s^r. After applying corrections for simulation finite-size effects, the depletion potentials are compared with the prediction of new density functional theory (DFT) calculations based on the insertion trick using the Rosenfeld functional and several subsequent modifications. While agreement between the DFT and simulation is generally good, significant discrepancies are evident at the largest reservoir packing fraction accessible to our simulation methods, namely \eta_s^r=0.35. These discrepancies are, however, small compared to those between simulation and the much poorer predictions of the Derjaguin approximation at this \eta_s^r. The recently proposed morphometric approximation performs better than Derjaguin but is somewhat poorer than DFT for the size ratios and small sphere packing fractions that we consider. The effective potentials from simulation, DFT and the morphometric approximation were used to compute the second virial coefficient B_2 as a function of \eta_s^r. Comparison of the results enables an assessment of the extent to which DFT can be expected to correctly predict the propensity towards fluid fluid phase separation in additive binary hard sphere mixtures with q\leq 0.1.Comment: 16 pages, 9 figures, revised treatment of morphometric approximation and reordered some materia