Self-supervised role learning for graph neural networks

Knowledge and Information Systems - We present InfoMotif, a new semi-supervised, motif-regularized, learning framework over graphs. We overcome two key limitations of message passing in popular...     

Densification and Sintering Viscosity of Low-Temperature Co-Fired Ceramics

In this paper, we present sintering and uniaxial viscosity data of three commercial low-temperature co-sintered ceramic systems, i.e., DuPont 951Tape (DU), Heraeus CT2000 (CT), and Ferro A6M (FE), measured by cyclic loading dilatometry. The viscosity initially decreases with temperature, changes little during the intermediate stage, and increases towards the end of densification. The viscosity increases sharply beyond the onset of crystallization. At slower heating rates, the viscosity increases at lower temperature, because of densification and crystallization. The isothermal viscosity data range from 0.1 to 100 GPa·s between 73% and 95% density. Ceramic particle-filled glasses show a higher isothermal viscosity compared with pure glass system, i.e., FE. From master viscosity curves based on isothermal data, the activation energies for viscous flow were ∼375±30 and 450±10 kJ/mol for DU and FE, respectively. These energies are comparable to values obtained from the master sintering curve approach.     

Determination on the Effect of Ti Addition on the Microstructural,Mechanical and Wear Behavior of Cu–6Sn Alloy in as—Cast Condition

The objective of this research is to fabricate a ternary alloy (Cu–Sn–Ti), incorporating titanium into bronze with varying weight percentage of titanium (0.5 wt%, 1 wt%) to investigate its impact on microstructural and mechanical properties and wear behavior and to collate these results with those of conventional bronze (Cu–6Sn). The microstructure of the alloys was observed using a metallurgical microscope, and results exhibit a finer grain refinement in the dendritic structure, which causes an improvement in mechanical properties. The mechanical properties were tested (tensile strength, hardness), and they showed an increment in values corresponding to the increase in the weight percentage of titanium. However, owing to the formation of an inclusion (blowhole), there was a reduction in the tensile strength for Cu–6Sn.0.5Ti. The wear analysis was also carried out using a pin-on-disk tribometer with selected parameters of load (10–30 N), sliding distance (1000 m) and sliding velocity (1–3 m/s), and it was noted that there was an increase in the wear rate with an increase in load and distance for all combinations of parameters. There was also an improvement in the wear resistance with an increase in the weight percentage of Ti, in comparison with the conventional base alloy.     

Dynamic response of 1-in. form factor disk drives to external shock and vibration loads

The dynamic response of the head disk interface is investigated numerically for two different designs of 1-in. hard disk drive enclosures, the so-called “thin” enclosure and the “thick” enclosure. First, the in-plane and out-of-plane vibration response is determined. Then, the effects of linear shock and head slap are studied. Simulation results show that the thinner enclosure has better performance with respect to forced vibrations in terms of reduced amplitude of slider vibrations. In addition, the effect of operational shock on the dynamic characteristics of textured and untextured sliders is studied. A finite element formulation of the time-dependent Reynolds equation (with Boltzmann slip flow correction) was used to obtain the air bearing response. The results show that the dynamic flying characteristics of textured sliders are improved compared to that of untextured sliders.     

An Enhanced Inter-carrier Interference Reduction Scheme for OFDM System with Phase Noise

Inter-carrier interference (ICI) reduction techniques achieve a better carrier-to-interference ratio (CIR) in OFDM system in the presence of synchronisation errors. However, the frequency diversity available on the frequency-selective channel has not been utilised by conventional ICI reduction techniques. In this paper, the frequency diversity of ICI reduction methods in the presence of phase noise over frequency-selective fading channels is analysed. Based on the analysis, an ICI reduction technique is proposed, enhanced symmetric data-conjugate (ESDC) technique, to enhance the frequency diversity in multipath fading channel. The carrier-to-interference ratio (CIR) and common phase error (CPE) of the proposed ICI reduction scheme are derived and the BER performance of the proposed system is compared with the conventional ICI reduction methods such as adjacent data-conjugate (ADC) and symmetric data-conjugate (SDC) methods. Simulation results reveal that the proposed ICI reduction scheme provides an improvement in BER performance over a fading channel and it is also better than conventional ICI reduction techniques in the presence of ICI due to phase noise.     

Efficient and Resilient Backbones for Multihop Wireless Networks

We consider the problem of finding "backbones" in wireless networks. The backbone provides end-to-end connectivity, allowing non-backbone nodes to save energy since they do not route or forward non-local data. Ideally, such a backbone would be small, consist primarily of high capacity nodes, and remain connected even when nodes move or fail. Unfortunately, it is often infeasible to construct a backbone that has all of these properties, e.g., a small optimal backbone is often too sparse to handle node failures or high mobility. We present a parameterized backbone construction algorithm that permits explicit tradeoffs between backbone size, resilience to node movement and failure, energy consumption, and path lengths. We prove that our scheme can construct essentially best possible backbones (with respect to energy consumption and backbone size) when the network is relatively static. We generalize our scheme to build more robust structures better suited to high-mobility scenarios. We present a distributed protocol based upon our algorithm and show that this protocol builds and maintains a connected backbone in dynamic networks. Finally, we present detailed packet-level simulations to evaluate and compare our scheme against existing energy-saving techniques. Depending on the network environment, our scheme increases network lifetimes by 20—220% without adversely affecting network performance.     

Engagement characteristics of a friction pad for commercial vehicle clutch system

A commercially available sintered friction pad is coupled with a standard gray cast iron pressure plate (FG 250 grade) and tested in a clutch dynamometer for understanding the engagement characteristics and thereby predicting the useful life in number of engagements. Results show that sintered friction pad has a very stable range of friction coefficient (0.43–0.61) even after 5000 engagement cycles. The torque transmitted ranges from 350 to 400N during one engagement cycle. The energy dissipation and mass loss of friction materials linearly increases with increasing sliding distance. A correlation is derived based on energy dissipation and mass loss in terms of total number of useful or available engagements before replacement or repair of friction pad or clutch pressure plate. Both the pressure plate and clutch disc with the sintered friction pad was tested in a 49 tons load capacity vehicle on a test track. Both sintered friction pad and pressure plate showed scoring marks along the sliding direction. Friction pad showed dense cracks along the top edge. Microscopic features of worn sintered friction pads show silica particle providing the required wear resistance for the pads. Pressure plate showed transfer layer of oxides and carbon with less scoring marks due to short duration vehicle level trials.