An effective FoV restriction approach to mitigate VR sickness on mobile devices

It has been noted that restricting field of view (FoV) is effective to mitigate virtual reality (VR) sickness, but it is prone to reduce the immersiveness. We propose an effective FoV restriction approach to mitigate VR sickness on mobile devices. The proposed approach includes a practical and reliable method for measuring VR sickness and a method of effectively limiting the FoV on mobile VR devices. Experimental result shows that the proposed method reduces VR sickness by 31.4%. The method was successfully applied to a VR application.     

Electrical transport and thermoelectric properties of Ca0.8Y0.2−xDyxMnO3−δ (0 ≤ x ≤ 0.2)

Ca_0.8Y_0.2?xDy_xMnO_3?δ (0≤x≤0.2) samples were fabricated by the solid‐state reaction method, and their thermoelectric properties were studied from 500°C to 800°C. Upon the substitution of Dy³⁺ for Y³⁺ in the Ca_0.8Y_0.2?xDy_xMnO_3?δ, the electrical and thermal conductivities gradually decreased with increasing Dy³⁺ concentration, whereas the absolute value of the Seebeck coefficient significantly increased. The Ca_0.8Dy_0.2MnO_3?δ showed the largest value of dimensionless figure of merit (0.180) at 800°C as a result of the combination of the largest absolute value of the Seebeck coefficient and the lowest thermal conductivity. We believe that the Ca_0.8Dy_0.2MnO_3?δ is a promising thermoelectric material at high temperatures.     

Removal of biofilms using carbon dioxide aerosols

The formation of biofilm (bacterial film) has been serious concerns in a wide variety of applications, because it is involved in many human and device-associated infections. We present a novel method of effectively and rapidly removing Escherichia coli (XL1-blue) biofilm from a silicon chip, using carbon dioxide aerosols. The aerosols were generated by adiabatic expansion of a high-pressure CO₂ gas through a nozzle and they were applied to biofilms that had been grown for 24 h on silicon chips. We measured the percentage area cover of the bacteria from the scanning electron micrographs taken before and after applying the aerosols. The decrease in the percentage area cover, caused by the aerosols, was measured as several parameters such as the distance between the nozzle and the chip, the angle of the nozzle axis relative to the horizontal, CO₂ stagnation pressure, rinsing solution, the aerosol exposure time, and drying time were varied. Nearly 100% of the biofilms were removed within 90 s whether the chip surfaces were very humid (no-drying) or dry (7 h-drying) immediately before applying the aerosols. This method has potential application to cleaning of a wide variety of bio-contaminated surfaces.     

Efficacy of Sanitized Ice in Reducing Bacterial Load on Fish Fillet and in the Water Collected from the Melted Ice

ABSTRACT: This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PRO-SAN^® (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PRO-SAN^® and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for cross-contamination.     

Effects of planar inlet plenums on the hydrodynamically developing flows in rectangular microchannels of complementary aspect ratios

The effects of planar inlet plenum geometry on the developing flow fields in two rectangular microchannels of reciprocal aspect ratios (H/W ∼2.75 and ∼0.40) were investigated for Re _D =  1–100 using micro particle image velocimetry (μPIV). These two microchannels were made by a precision sawing and silicon microfabrication techniques. Both the velocity profiles and centerline velocity developments were clearly resolved and extracted along the axial distance from μPIV results. The entrance lengths were found from the centerline velocities using a decaying exponential fitting function where the centerline velocity reaches 99% of the fully developed centerline velocity. The proposed fitting function showed excellent agreement with the experimental results. The planar plenum was shown to cause an upstream predevelopment resulting in the significant reductions in the entrance lengths. Two entrance length correlations were proposed in the forms of Atkinson et al.’s (AIChE J 15:548–553, 1969) and Chen’s (J Fluids Eng 95:153–158, 1973) correlations. The proposed entrance length correlations showed that acquired constant portion and slope of the entrance lengths showed 23–27 and 70–81% reductions for H/W =  2.75 while the entrance length correlation for H/W =  0.40 showed 69–73% increase and 41–63% decrease in the constant portion and slope, respectively.     

A novel method for VR sickness reduction based on dynamic field of view processing

Virtual Reality - In this paper, we proposed a novel method for virtual reality (VR) sickness reduction based on dynamic field of view (FOV) processing. Dynamic FOV processing is performed based on...     

Cyclic shifted orthogonal complementary codes for multicarrier CDMA systems

In this letter, we present a set of cyclic shifted orthogonal complementary (cyclic-OC) codes for multicarrier CDMA systems. The conventional OC codes are not adequate for the system because they are able to support only the limited number of users. By applying the proposed cyclic-OC codes for the inter-symbol interference (ISI)-free multicarrier systems, the number of users can be extended to the size of code length. We validate the effectiveness of the proposed scheme through simulations.     

A Polygonal Method for Ranging-Based Localization in an Indoor Wireless Sensor Network

In this paper, we propose an indoor localization method in a wireless sensor network based on IEEE 802.15.4 specification. The proposed method follows a ranging-based approach using not only the measurements of received signal strength (RSS) but also the coordinates of the anchor points (APs). The localization accuracy depends on the errors in the distance estimation with the RSS measurements and the size of the polygon composed of the APs used for the lateration. Since errors are inevitably involved in the RSS measurement, we focus on reducing the size of the polygon to increase the localization accuracy. We use the centroid of the polygon as a reference point to estimate the relative location of a target in the polygon composed of the APs hearing the target. Once the relative position is estimated, only the APs covering the area are used for localization. We implement the localization method and evaluate the accuracy of the proposed method in various radio propagation environments. The experimental results show that the proposed method improves the localization accuracy and is robust against the dynamically changing radio propagation environments over time.