Empirical Comparisons of Virtual Environment Displays

There are many different visual display devices used in virtual environment (VE) systems. These displays vary along many dimensions, such as resolution, field of view, level of immersion, quality of stereo, and so on. In general, no guidelines exist to choose an appropriate display for a particular VE application. Our goal in this work is to develop such guidelines on the basis of empirical results. We present two initial experiments comparing head-mounted displays with a workbench display and a foursided spatially immersive display. The results indicate that the physical characteristics of the displays, users' prior experiences, and even the order in which the displays are presented can have significant effects on performance

Adoption and impacts of zero tillage as a resource conserving technology in the irrigated plains of South Asia

Zero tillage / Rice / Wheat / Water conservation / India / Pakistan / Haryana / Punjab

Using Hubble Parameter Measurements to Find Constraints on Dark Energy Based on Different Cosmological Models

In this paper, Hubble parameter versus redshift data, collected from multiple resources, is used to place constraints on the parameters of two current Cosmological dark energy models. The first dark energy model considered is the Standard Model of cosmology, also known as ΛCDM with spatial curvature, which is primarily based on Einstein’s General Theory of Relativity with a spatially homogeneous time-independent cosmological constant, Λ. The second is the XCDM model which parameterize dark energy as a fluid whose density can vary with time. The H(z) data collected through different experimental sources was used to put constraints on the parameters of these models. The constraints obtained are then compared with the previously obtained constraints using different probes like type-1a supernovae, distance modulus, CMB anisotropy, and baryonic acoustic oscillations peak length scale. The results of analyzing the Hubble parameter vs redshift data is consistent with previous conclusions that we live in an approximately flat, accelerating Universe. However, in order to deduct tighter constraints on cosmological models’ parameter, like the geometry of the Universe, more and better-quality data will be neede

Properties of blended mortars produced with recycled by-products from different waste streams

The construction industry encounters significant challenges in effectively managing solid waste produced during the extraction and production of building materials. In different countries, slurry waste generated from granite and marble processing industries, such as glass industry waste, constitutes a considerable portion of the total solid waste. Its undesirable disposal is causing unprecedented environmental damage. Using these non-biodegradable wastes to produce building materials would reduce the environmental burden and contribute to sustainable construction. This study, in detail, investigates the feasibility of utilizing Granite Powder (GP), Ground Granite Powder (GGP), and Ground Glass Waste (GGW) as partial replacements of components in blended mortar mixes. The mix modifications consist of partial replacement of cement with GGW, GP, and GGP in the range of 5–15% and fine aggregate replacement with Marble powder (MP) in 10–30% by mass. The mechanical, physical, and microstructure properties of blended and control mortar mixes were studied on the 3rd, 7th, 28th, and 91st curing days. The results demonstrate that the partial substitution of 10% GGW and 5% GP with cement and 10% MP with fine aggregates in blended mortars enhance the compressive strength at the later curing age (28 and 91 days) compared to that of a control mortar, which is associated to the development of higher pozzolanic reactivity. The XRD results showed the formation of the lowest content of calcium hydroxide (CH) and the highest content of calcium silicate gel in the blended mortars compared to the control mortar. The results enrich the data available in the literature not always univocal, as in the case of using marble and glass waste, providing also interesting information about the influence of granite powder on the hydration process in a mortar mix actually missing

Research challenges in 5G networks: a HetNets perspective

This paper highlights use cases, emerging machine type communication (MTC) technologies, ongoing research activities, and existing research challenges in 5G networks. 5G networks are faced with the following challenges: (i) handling large amounts of data, (ii) coping with different types of data traffic, i.e., human-type, machine-type, and combined-type (iii) connecting billions of machines, and (iv) severe resource limitations of devices. The ubiquitous nature of cellular networks make them the preferred choice for access networks, but a lack of communication resources is a problem. To address the resource scarcity issue, different wireless access networks may combine to form a heterogeneous network (HetNet) and hence become a single 5G network. For long-term success of 5G networks, we envision the following as important research outputs: (i) a scalable 5G network architecture that can handle a large number of human users and machines considering different constraints, (ii) a comprehensive quality of service (QoS) framework to satisfy heterogeneous users and machines requirements, (iii) a procedure for intelligent access network selection, and (iv) comprehensive inter-network handover mechanisms

HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON THE REDSHIFT OF THE DECELERATION-ACCELERATION TRANSITION, DYNAMICAL DARK ENERGY, AND SPACE CURVATURE

Citation: Farooq, O., Madiyar, F. R., Crandall, S., & Ratra, B. (2017). HUBBLE PARAMETER MEASUREMENT CONSTRAINTS ON THE REDSHIFT OF THE DECELERATION-ACCELERATION TRANSITION, DYNAMICAL DARK ENERGY, AND SPACE CURVATURE. Astrophysical Journal, 835(1), 11. doi:10.3847/1538-4357/835/1/26We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 <= z <= 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, z(da), from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H-0. The weighted mean of our measurements is z(da) = 0.72 +/- 0.05 (0.84 +/- 0.03) for H-0 = 68 +/- 2.8 (73.24 +/- 1.74) km s(-1) Mpc(-1) and should provide a reasonably model-independent estimate of this cosmological parameter. The H(z) data are consistent with the standard spatially flat.CDM cosmological model but do not rule out nonflat models or dynamical dark energy models

Breadfruit starch-wheat flour noodles: preparation, proximate compositions and culinary properties

Proximate compositions, culinary and sensory properties of noodles prepared from proportionate combinations of breadfruit starch and wheat flour were investigated. Breadfruit starch (BS) isolated from matured breadfruit (Artocarpus altilis) was used to produce noodles in combination with hard red wheat flour (WF) at a ratio of 100% WF:0% BS, 80% WF:20% BS, 60% WF:40% BS, 40% WF:60% BS, 20% WF:80% BS. The protein, fat, ash, crude fibre and moisture contents of the Breadfruit starch-Wheat flour (BSWF) noodles prepared from the above blends ranged from 0.65 to 10.88%, 0.35 to 3.15%, 1.28 to 2.25%, 1.18 to 1.45% and 4.65 to 5.45%, respectively. The contents of protein, fat, ash and crude fibre increased as the percentage breadfruit starch decreased. However, values of moisture content did not follow the same trend, instead higher values were found for 100% BS:0% WF (5.35%) and 20% BS:80% WF (5.45%). The cooking yield of the BSWF noodles ranged from 21.02 (60% BS:40% WF) to 23.75 g (100% BS:0% WF), cooking loss ranged from 5.49 (20% BS:80% WF) to 9.19% (100% BS:0% WF), while swelling index ranged from 3.1 (20% BS:80% WF) to 3.4 (100% BS:0% WF). Throughout the study, noodles produced from blends of 20% breadfruit starch and 80% wheat flour showed superior proximate, culinary and sensory attributes

RPL-based routing protocols for multi-sink wireless sensor networks

Recent studies demonstrate that the performance of a wireless sensor network (WSN) can be improved by deploying multiple sinks in the network. Therefore, in this paper we present different routing protocols for multi-sink WSNs based on the routing protocol for low-power and lossy networks (RPL). Our protocols use different routing metrics and objective functions (OFs). We use the available bandwidth, delay, MAC layer queue occupancy, and expected transmission count (ETX) as the tie-breaking metrics in conjunction with the shortest hop-count metric. Our OFs use the tie-breaking metrics on a greedy or end-to-end basis. Our simulation results demonstrate that the protocols based on the delay, buffer occupancy, and ETX metrics demonstrate best performance, increasing the packet delivery ratio by up to 25% and decreasing the number of retransmissions by up to 65%, compared to a version of the RPL protocol that only uses the hop-count metric. Another key insight is that, using the tie-breaking metrics on a greedy basis demonstrates a slight performance improvement compared to using the metrics on an end-to-end basis. Finally, our results also demonstrate that multiple sinks inside a WSN improve the RPL-based protocol performance