A cost-effective heuristic to schedule local and remote memory in cluster computers

Cluster computers represent a cost-effective alternative solution to supercomputers. In these systems, it is common to constrain the memory address space of a given processor to the local motherboard. Constraining the system in this way is much cheaper than using a full-fledged shared memory implementation among motherboards. However, memory usage among motherboards can be unfairly balanced.     

College students’ disclosure of location-related information on Facebook

This study drew on existing research and three behavioral intention models to develop the beginning of a new model to explain why college students share their locations on Facebook. Findings showed that students were more likely to disclose their location on Facebook if their friends did so, a concept called subjective norm. Results also showed that subjective norm had an indirect effect on whether people disclosed their location, mediated through people’s attitude toward disclosure, while controlling for usefulness of disclosing. Collectively, this model explained 61% of the variance in why college students share locations on Facebook. Findings are discussed in relation to behavioral-intention models, and practical implications for social media companies are offered.     

Validation of the sensitive and accurate quantitation of the fatty acid distribution in bovine milk

A method for the precise analysis of the complex mixture of fatty acids in milk has been developed and validated. The triacylglycerol of nonanoic acid was applied as the internal standard (ISTD) for absolute quantification. Milk lipids were extracted by miniaturised ultrasonication and methylated with trimethylsulfonium hydroxide. Resulting fatty acid methyl esters were determined by gas chromatography with flame ionisation detection giving excellent resolution, including separation of several 18:1 isomers. The low quantitation limit (0.01 mg mL⁻¹ milk) indicates that the sensitivity of the method is sufficient to quantify up to 50 fatty acids, from 4:0 to 23:0. Measurements of precision provided excellent results for different bovine milk samples of different fat content (coefficient of variance: 1.9% and 9.8% for intra- and interday precision, respectively). Recovery averaged 108 ± 3.5%. Evaluation of methods for determining the total fat content showed that gravimetry is no longer needed when using the ISTD.     

Sex role stereotyping is hard to kill: A field experiment measuring social responses to user characteristics and behavior in an online multiplayer first-person shooter game

Sex role stereotyping by players in first-person shooter games and other online gaming environments may encourage a social environment that marginalizes and alienates female players. Consistent with the social identity model of deindividuation effects (SIDE), the anonymity of online games may engender endorsement of group-consistent attitudes and amplification of social stereotyping, such as the adherence to gender norms predicted by expectations states theory. A 2 × 3 × 2 virtual field experiment (N = 520) in an online first-person shooter video game examined effects of a confederate players’ sex, communication style, and skill on players’ compliance with subsequent online friend requests. We found support for the hypothesis that, in general, women would gain more compliance with friend requests than men. We also found support for the hypothesis that women making positive utterances would gain more compliance with friend requests than women making negative utterances, whereas men making negative utterances would gain more compliance with friend requests than men making positive utterances. The hypothesis that player skill (i.e., game scores) would predict compliance with friend requests was not supported. Implications for male and female game players and computer-mediated communication in online gaming environments are discussed.     

Screening of adhesive lactobacilli with antagonistic activity against Campylobacter jejuni

In the present study, 78 lactic acid bacteria (LAB) strains were screened for the antagonistic activity against Campylobacter jejuni and 15 LAB strains with high bactericidal capacity were selected for further study through the analysis of the inhibition zone of LAB spent culture supernatant on the growth of C. jejuni. Among these strains, four isolates, Lactobacillus plantarum N8, N9, ZL5 and Lactobacillus casei ZL4 exhibited high adhesion ability to HT-29 cells. All the cell free supernatant (CFS) of these four strains contained high concentration of organic acid and their inhibition effects against C. jejuni were pH sensitive. Furthermore, these four strains could strongly antagonize the adhesion and invasion of C. jejuni to HT-29 cells and showed good tolerance to artificial gastric and small intestinal juices. This study suggests that Lactobacillus strains N8, N9, ZL4 and ZL5 could be used as potential probiotics in food applications against C. jejuni infection.     

Vision-based action recognition of earthmoving equipment using spatio-temporal features and support vector machine classifiers

Video recordings of earthmoving construction operations provide understandable data that can be used for benchmarking and analyzing their performance. These recordings further support project managers to take corrective actions on performance deviations and in turn improve operational efficiency. Despite these benefits, manual stopwatch studies of previously recorded videos can be labor-intensive, may suffer from biases of the observers, and are impractical after substantial period of observations. This paper presents a new computer vision based algorithm for recognizing single actions of earthmoving construction equipment. This is particularly a challenging task as equipment can be partially occluded in site video streams and usually come in wide variety of sizes and appearances. The scale and pose of the equipment actions can also significantly vary based on the camera configurations. In the proposed method, a video is initially represented as a collection of spatio-temporal visual features by extracting space–time interest points and describing each feature with a Histogram of Oriented Gradients (HOG). The algorithm automatically learns the distributions of the spatio-temporal features and action categories using a multi-class Support Vector Machine (SVM) classifier. This strategy handles noisy feature points arisen from typical dynamic backgrounds. Given a video sequence captured from a fixed camera, the multi-class SVM classifier recognizes and localizes equipment actions. For the purpose of evaluation, a new video dataset is introduced which contains 859 sequences from excavator and truck actions. This dataset contains large variations of equipment pose and scale, and has varied backgrounds and levels of occlusion. The experimental results with average accuracies of 86.33% and 98.33% show that our supervised method outperforms previous algorithms for excavator and truck action recognition. The results hold the promise for applicability of the proposed method for construction activity analysis.     

Effects of preparation conditions on the morphology and performance of palladium nanostructures

Three-dimensional palladium nanoflowers (PdNF) composed of ultrathin Pd nanosheets had been synthesized by a solvothermal approach in our previous work. Here, the effects of preparation conditions on the morphology and electrochemical performance of palladium nanostructures were investigated. The explored conditions are as follows: the ratio of reducing agent to capping agent, the concentration of PdCl₂ precursor, the amount of HCl (used for PdCl₂ dissolution), the reaction temperature and time. Only when these conditions are strictly controlled, the obtained Pd material displays a uniformly nanoflower-like morphology, otherwise the Pd samples with nanoparticles or incomplete flowers can only be obtained. Then, the relationship between the morphology of Pd and its electrocatalytic activity was further studied. The results indicate that the Pd with perfect nanoflowers morphology possesses superior activity for formic acid electro-oxidation, while the Pd with incomplete flowers and ordinary (or irregular) particle morphology shows moderate and inferior activity. Therefore, the morphology-dependent electrocatalytic activity has been demonstrated in this work.     

Open loop wind turbine emulator

A new wind turbine emulator (WTE) is presented, which is able to simulate the turbine power curves without using a closed loop control system. The state of the art emulators use DC or AC motors, closed loop controlled by processors with the turbine power curves recorded. The presented emulator has a DC voltage source, a power resistor and a DC motor with independent excitation. The motor power curve has a shape similar to a wind turbine power curve for a given wind speed; the wind speed variations can be emulated by the variations of the DC voltage source. The open loop emulator is completely different and new, because it works in open loop and does not require the presence of a processor.The following elements are included: the theoretical foundations of the emulator, the emulator power curves adjustment procedure to simulate a commercial wind turbine and the experimental tests.     

Wireless telemetry system for real-time estimation of ship air wakes with UAVs

This paper presents a wireless instrumentation system developed for real-time estimation of air turbulence patterns arising from the interaction of wind with any structure under consideration, which is an important study in the aerospace industry. In particular, this paper focuses on the application of the proposed system in a naval research problem for off-board measurement of ship air wake patterns using an instrumented radio controlled (RC) helicopter. We propose the use of an Inertial Measurement Unit (IMU) as a sensor to measure air wake in the form of induced vibrations on the helicopter while it maneuvers through regions of active air wake. The proposed system makes use of Back Propagation Neural Networks to compensate for the vibrational noise contributed by pilot inputs. The instrumentation system was integrated and tested on a modified training vessel in the Chesapeake Bay, which provided a wide range of wind conditions.     

Transient dual interface measurement of junction-to-case thermal resistance in AlGaN/GaN HEMT utilizing an improved infrared microscope

The junction-to-case thermal resistance (R_θJC) of a GaN/AlGaN HEMT is measured by Transient Dual Interface Method (TDIM). Different from other works about TDIM, an improved transient infrared microscope is used to measure the cooling curves, other than the traditional electrical method. Z_th curves are used to determine the R_θJC following the procedure of JESD51-14. The results demonstrate that the R_θJC at 40 W power dissipation are about 0.791 K/W. In order to validate the method, measurements following MIL Std 833 have been done, and the results are consistent with the existing papers.