Snapchat\u27s Ability to Build and Maintain Friendships

In a world of rapidly advancing technology, understanding social media is very important. Snapchat has been able to shed its early negative reputation to become one of the most consistently popular applications on the market. The purpose of this study is to understand how Snapchat users, use the app to build and maintain friendships. The study will also determine how Snapchat effects different levels of social relationships. The qualitative research method was used to conduct interviews of active Snapchat users. The questions required detailed and descriptive answers based on participants past experiences using Snapchat. The data was examined for themes and commonalities, finding that primary interaction on Snapchat is between to strong friends. Interaction with less personal ties is rare to nonexistent. That indicates that interaction on Snapchat, requires a strong social bond on a personal level, before connecting digitally

Optimization of a PID Controller within a Dynamic Model of a Steam Rankine Cycle with Coupled Energy Storage

Fusion energy is an appealing option for future energy generation, but also presents unique design challenges. The UK Atomic Energy Authority is leading the Spherical Tokamak for Energy Production (STEP) programme to build a fusion power plant capable of net electricity generation. This work addresses the use of dynamic models in an optimization framework for the design of the thermal power generation cycle for STEP. The optimization of a proportional-integral-derivative controller regulating the power output of a steam Rankine cycle with a coupled thermal energy storage system is presented. A lumped-parameter dynamic model of the system has been implemented. The effectiveness of a controller design is evaluated by simulating the system under a perturbation to the power demand on the system. By minimizing the mean absolute power deviation, there is a reduction of 97 % compared to the initial controller design, as well as a reduction of 95 % in the maximum absolute power deviation and a faster return to setpoint. The optimized design does introduce more oscillations in the system, which are undesirable for control systems and are challenging for the optimization procedure

University of Hawaii\u27s Spaceflight-Ready, Low-Cost, Open-Source, Educational Artemis CubeSat Kit

The Artemis CubeSat Kit is a spaceflight-ready, low-cost, educational 1U CubeSat kit, which acts as a foundation enabler in aerospace engineering education and commercializing small satellites. The hardware kit accompanies a standalone Spacecraft Mission Design curriculum in the public domain, which includes a self-guided course outline, textbook, and digital lab modules. Funded by NASA\u27s Artemis Student Challenge Program, the Kit is developed and maintained by students attending the University of Hawaii at Manoa and supervised by the Hawaii Space Flight Laboratory (HSFL). The purpose of the Artemis CubeSat Kit and accompanying curriculum is to provide educational accessibility for university-level students and faculty interested in designing, building, and flying their own small satellite missions. This paper describes the technical design of the Artemis 1U CubeSat, the topology of the standalone curriculum, and the lessons learned by the team while developing the Artemis CubeSat Kit

Far infrared luminosity function of local galaxies in the AKARI Deep Field South

We present the first far-infrared luminosity function in the AKARI Deep Field South, a premier deep field of the AKARI Space Telescope, using spectroscopic redshifts obtained with AAOmega. To date, we have found spectroscopic redshifts for 389 galaxies in this field and have measured the local (z<0.25) 90 μm luminosity function using about one-third of these redshifts. The results are in reasonable agreement with recent theoretical predictions

Functional diversity metrics can perform well with highly incomplete data sets

Characterising changes in functional diversity at large spatial scales provides insight into the impact of human activity on ecosystem structure and function. However, the approach is often based on trait data sets that are incomplete and unrepresentative, with uncertain impacts on functional diversity estimates. To address this knowledge gap, we simulated random and biased removal of data from three empirical trait data sets: an avian data set (9579 species), a plant data set (2185 species) and a crocodilian data set (25 species). For these data sets, we assessed whether functional diversity metrics were robust to data incompleteness with and without using imputation to fill data gaps. We compared two metrics each calculated with two methods: functional richness (calculated with convex hulls and trait probabilities densities) and functional divergence (calculated with distance-based Rao and trait probability densities). Without imputation, estimates of functional diversity (richness and divergence) for birds and plants were robust when 20%–70% of species had missing data for four out of 11 and two out of six continuous traits, respectively, depending on the severity of bias and method used. However, when missing traits were imputed, functional diversity metrics consistently remained representative of the true value when 70% of bird species were missing data for four out of 11 traits and when 50% of plant species were missing data for two out of six traits. Trait probability densities and distance-based Rao were particularly robust to missingness and bias when combined with imputation. Convex hull-based estimations of functional richness were less reliable. When applied to a smaller data set (crocodilians, 25 species), all functional diversity metrics were much more sensitive to missing data. Expanding global morphometric data sets to represent more taxa and traits, and to quantify intraspecific variation, remains a priority. In the meantime, our results show that widely used methods can successfully quantify large-scale functional diversity even when data are missing for half of species, provided that missing traits are estimated using imputation. We recommend the use of trait probability densities or distance-based Rao when working with large incomplete data sets and filling data gaps with imputation

AKARI and IRAS: From beam corrections to SEDs

There is significant scientific value to be gained from combining AKARI fluxes with data at other far-infrared (IR) wavelengths from the Infrared Astronomical Satellite (IRAS) and Herschel missions. To be able to do this we must ensure that there are no systematic differences between the data sets that need to be corrected before the fluxes are compatible with each other. One such systematic effect identified in the Bright Source Catalog version 1 (BSCv1) data is the issue of beam corrections. We determine these for the BSC version 2 (BSCv2) data by correlating ratios of appropriate IRAS and AKARI bands with the difference in 2 Micron All Sky Survey (2MASS) J-band extended and point source magnitudes for sources cross-matched between the IRAS Faint Source Catalog (FSC), AKARI BSCv2 and 2MASS catalogs. We find significant correlations (p ≪ 10 −13) indicating that beam corrections are necessary in the 65 and 90 μm bands. We then use these corrected fluxes to supplement existing data in spectral energy distribution (SED) fits for ultraluminous infrared galaxies (ULIRGs) in the Herschel ULIRG Survey (HERUS). The addition of AKARI fluxes makes little difference to the results of simple (T, β) fits to the SEDs of these sources, though there is a general decrease in reduced χ2 values. The utility of the extra AKARI data, however, is in allowing physically more realistic SED models with more parameters to be fitted to the data. We also extend our analysis of beam correction issues in the AKARI data by examining the Herschel Reference Sample (HRS) galaxies, which have Herschel photometry from 100 to 500 μm and which are more spatially extended than the HERUS ULIRGs. 34 of the HRS sources have good Herschel SEDs and matching data from AKARI. This investigation finds that our simple 2MASS-based beam correction scheme is inadequate for these larger and more complex sources. There are also indications that additional beam corrections at 140 and 160 μm are needed for these sources, extended on scales >1′

Timeline analysis and wavelet multiscale analysis of the AKARI All-Sky Survey at 90 micron

We present a careful analysis of the point source detection limit of the AKARI All-Sky Survey in the WIDE-S 90 $\mu$m band near the North Ecliptic Pole (NEP). Timeline Analysis is used to detect IRAS sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90 $\mu$m flux of a source. Combined with a robust noise measurement, the point source flux detection limit at S/N $>5$ for a single detector row is $1.1\pm0.1$ Jy which corresponds to a point source detection limit of the survey of $\sim$0.4 Jy. Wavelet transform offers a multiscale representation of the Time Series Data (TSD). We calculate the continuous wavelet transform of the TSD and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above $4\sigma$ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non-IRAS sources detected in Timeline Analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non-IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.Comment: 16 pages, 19 figures, 5 tables, accepted for publication in MNRA

AKARI Deep Field South: spectroscopic observations of infrared sources

We present a summary of our spectroscopic redshift catalogue of 404 sources in the AKARI Deep Field South (ADF-S). We have used the AAOmega spectrograph to target mid-infrared and far-infrared sources selected primarily from AKARI observations in this field for which we were able to obtain optical counterparts. Our sources with identified redshifts include 316 with Hα detections at z ≤ 0.345 and 15 sources at z > 1 with MgII or Lα emission lines. About 13% of our z ≤ 0.345 sources are dominated by active galactic nuclei (AGN) emission, although many show emission from both star formation and AGNs. The median Balmer decrement is 5.9. Ultra-luminous infrared galaxies (ULIRGs) were found only in the higher-redshift sources. Optical and near infrared data will be available shortly, enabling calibration of the line luminosities and spectral energy distribution (SED) fitting for these sources