207 research outputs found
Generalized Instantly Decodable Network Coding for Relay-Assisted Networks
In this paper, we investigate the problem of minimizing the frame completion
delay for Instantly Decodable Network Coding (IDNC) in relay-assisted wireless
multicast networks. We first propose a packet recovery algorithm in the single
relay topology which employs generalized IDNC instead of strict IDNC previously
proposed in the literature for the same relay-assisted topology. This use of
generalized IDNC is supported by showing that it is a super-set of the strict
IDNC scheme, and thus can generate coding combinations that are at least as
efficient as strict IDNC in reducing the average completion delay. We then
extend our study to the multiple relay topology and propose a joint generalized
IDNC and relay selection algorithm. This proposed algorithm benefits from the
reception diversity of the multiple relays to further reduce the average
completion delay in the network. Simulation results show that our proposed
solutions achieve much better performance compared to previous solutions in the
literature.Comment: 5 pages, IEEE PIMRC 201
Enhancing Grasp Pose Computation in Gripper Workspace Spheres
In this paper, enhancement to the novel grasp planning algorithm based on gripper workspace spheres is presented. Our development requires a registered point cloud of the target from different views, assuming no prior knowledge of the object, nor any of its properties. This work features a new set of metrics for grasp pose candidates evaluation, as well as exploring the impact of high object sampling on grasp success rates. In addition to gripper position sampling, we now perform orientation sampling about the x, y, and z-axes, hence the grasping algorithm no longer require object orientation estimation. Successful experiments have been conducted on a simple jaw gripper (Franka Panda gripper) as well as a complex, high Degree of Freedom (DoF) hand (Allegro hand) as a proof of its versatility. Higher grasp success rates of 76% and 85.5% respectively has been reported by real world experiments
Study of the Effect of Geomembranes on the Interaction between the Soil and Underground Structures
Geomembranes are one of the most widely used insulation materials in various civil engineering applications. Failure due to the slippage between geomembranes and the interfacing soils was detected at some cases. This paper presents the results of a series of laboratory tests carried out to investigate the factors controlling the developed interface stresses strength between the soil and geomembranes. In order to quantify the effect of different commonly used isolation membranes on the behavior and stability of buried concrete structures, laboratory studies by using modified direct shear apparatus is performed and integrated and the reduction in the shear resistance between the soil and different types of isolation geomembranes is determined. Graded sand with well-rounded particles was used in the experimental program. Shear tests were conducted under a normal stress range of about 25-100 kPa. The effect of the geomembranes on the peak and residual interface shear strengths is highlighted. Test’s results indicate development of peak interface shear resistance at a small strain and constant residual interface shear resistance at large strain. It was found that the developed peak and residual interface friction angles between the sand and the geomembranes interfaces ranged from 59 % to 82 % of the corresponding peak and residual interface friction angles between sand and un-protected concrete
Scaling Up Manufacturing of Edible Coatings for Food
One of the most important methods for prolonging the shelf life of fruits and vegetables is edible coatings. The manufacture of the edible coating was tested in the laboratory before being scaled up to the industrial scale which is a procedure for applying, which applies the same process to different output volumes. One of the most crucial processes in the manufacturing of edible coatings is mixing. The equipment needed to scale up the production of edible solutions for food coating was also assessed. The results of the measurements revealed that scaling up mixing is based upon constant power/volume, equal blend duration, and adjusting the impeller/tank (D/T) diameter ratio was possible. A four-blade impeller was utilized to homogenize 1% carrageenan solutions at 70°C. Also, mixing parameters (Power number, Blend number, and Pumping number) were determined at different D/T ratios. Cost-effective pipe diameter and optimum pipe diameter per unit length were also determined
Practitioner review: pathways to care for ADHD - a systematic review of barriers and facilitators
Background. Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder starting in childhood that may persist into adulthood. It can be managed through carefully monitored medication and nonpharmacological interventions. Access to care for children at risk of ADHD varies both within and between countries. A systematic literature review was conducted to investigate the research evidence related to factors which influence children accessing services for ADHD
Effect of adulteration on honey properties
Abstract Honey samples belong to clover plants (Trifolium alexandrinanum) (1, 3, 6, 12, and 24
Bearing Capacity of Driven Open-Ended Pipe Piles in Weak Soil Formations
Steel pipe piles have been increasingly used as deep foundations for offshore or onshore structures in weak soil formations. These piles are usually open-ended and installed to their final level using suitable hammers or vibrators relying on the subsurface conditions. Simultaneously, the soil plug (SP) forms inside the employed pipe pile during driving or installation. Moreover, it affects bearing behavior and total pile resistance. The experimental tests have been performed on a single tube pile. All tube piles were tested using the well-graded sand collected from the Egyptian desert, and the sand was prepared at medium density using a raining technique. The outcomes of the model pile tests showed that the value of plug resistance in open-ended pipe pile (OEPP) is typically on the order of 50% to 70% of the total pile load of OEPP, and it is influenced by pile thickness, pile diameter, pile length, and submerged state. Simultaneously, the plugging influence of OEPP increased with increasing pile thickness and embedded pile length. However, the plugging influence decreased with increasing pile diameter. The total pile load of OEPP increased with increasing the embedded pile length. It must be noted that the influence of pile length on the total pile load is greater than the influence of pile diameter; this refers to the pile length having a significant effect on the total pile load. This is due to an increase in the influence of SP
An Optimum Performance of A Flat-Type Solar Air Heater With A Porous Absorber
This investigation is concerned with the design and performance of a flat solar air heater in which air flows perpendicular from a vented transparent cover through a porous absorber plate. The design phase involves a stability analysis to determine the critical distance (maximum allowable distance) between the absorber and transparent plates, for suppressing convection currents, under a variety of environmental and operating conditions. These results are expected to be useful to designers of solar collectors.
In addition, the thermal performance of this solar heater at its optimum design conditions was computed for a wide range of system parameters illustrating the contributions of conduction and radiative modes of heat transfer. The results indicate that best operating efficiency can be obtained when running the collector with mass flow rate, m > 40 Kg/m2 hr
Grasping Unknown Objects Based on Gripper Workspace Spheres
In this paper, we present a novel grasp planning algorithm for unknown objects given a registered point cloud of the target from different views. The proposed methodology requires no prior knowledge of the object, nor offline learning. In our approach, the gripper kinematic model is used to generate a point cloud of each finger workspace, which is then filled with spheres. At run-time, first the object is segmented, its major axis is computed, in a plane perpendicular to which, the main grasping action is constrained. The object is then
uniformly sampled and scanned for various gripper poses that assure at least one object point is located in the workspace of each finger. In addition, collision checks with the object or the table are performed using computationally inexpensive gripper shape approximation. Our methodology is both time efficient (consumes less than 1.5 seconds in average) and versatile. Successful experiments have been conducted on a simple jaw gripper (Franka Panda gripper) as well as a complex, high Degree of Freedom (DoF) hand (Allegro hand)
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Integration v. Polarization Amongst Social Media Users: Perspectives through Social Capital Theory
There has been a growing debate about the extent to which social media has influenced the Arab World’s recent revolutions described as the “Arab Spring”. Despite difference in views concerning this issue, the role that social media played in enacting socio-political change is undeniable, a matter which attracted the interest of academia. Here, the power of social media in widening and strengthening relationships renovated and reinforced the concept of “social capital”, which could lead to integration or acculturation amongst affected societies. Underpinned by a social capital theory and the acculturation process, this commentary article adopts a critical approach and draws on historical events from the 2011 Egyptian revolution and beyond. We claim that, social media lead to social capital creation and integration when some fundamental associated factors exist namely: the bonding, bridging and linking factors. Social media adoption lead to political integration when these factors existed during the Egyptian revolution and lead to polarisation when there was no contextual triggering factor before the revolution and no access to resources after the revolution. We provide some insightful perspectives on the role of social media in social-political change
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