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An approach to solving the problems of fracture mechanics at the scale level of continuum mechanics is proposed. For an elementary volume element, within the framework of this approach, the onset of the moment of formation of new material surfaces is considered. A statement and a method for solving a particular problem of fracture mechanics are proposed.

The problem of tension and shear of a thin isotropic plate weakened by a doubly periodic system of rectilinear cracks with end zones is considered. General representations of solutions are constructed that describes a class of problems with a doubly periodic stress distribution outside cracks. The main singular integral equation of the problem is reduced to an infinite system of algebraic equations. Due to the unknown size of the end zone, the system of equations turned out to be non-linear even with a linear bond deformation law.

Kovir capsule, a polyherbal medicine developed from Ren Shen Bai Du San formulation, has been used in various diseases including respiratory infections. A randomized, placebo-controlled, double-blind study was conducted to evaluate the safety and efficacy of Kovir capsule (TD0069) in the treatment of mild COVID-19 patients. Patients aged from 18 to 65 years who were PCR-confirmed with SARS-CoV-2 and had the mild disease were recruited and randomized to either Kovir capsule (34 patients) or placebo (32 patients) for up to 14 days or until discharge. Efficacy outcomes were time to viral clearance, daily viral load, time to symptom resolution, daily symptom score based on 16 pre-defined symptoms, and progression to severe/critical COVID-19. Safety outcomes were adverse events. Viral load decreased over time similarly in the two groups. Viral clearance time was also similar in both groups (median: 8 days). Kovir group had a more rapid decrease of symptom score and significantly lower time to symptom resolution than placebo (median: 4 vs. 7 days). Two patients in the placebo group developed severe COVID-19. No patient experienced adverse events. Kovir capsule is safe and can improve symptom resolution in mild COVID-19 patients. A large-scale trial is required to confirm these findings.

We develop a physics based analytical model for AlGaN/GaN high electron mobility transistors (HEMT and MOS-HEMT) to study the I-V characteristics, current transfer characteristics, transconductance and drain-conductance. The model is modified from a model first presented by Chang and Fetterman for AlGaAs/GaAs HEMT (Chang and Fetterman in Solid-State Electron 30(5), 1987 [1], IEEE Trans Electron Dev Ed-34(I), 1987 [2]) The linear and non-linear drain currents have been separately calculated and merged them in order to evaluate the I-V characteristics. The threshold voltage has been evaluated from current transfer characteristics plot and verified from the transconductance parameter. We also consider the effect of polarization on threshold voltage of the devices. Moreover, to prove the exactness of our model, we compare our data with our experiment data for common HEMT, Hasan’s MOS-HEMT and Yoon’s HEMT with short channel.

In mobile communication environments, handover is a very important process to maintain mobile host’s connections to the network. Although a lot of researchers have tried to improve the handover performance, little deployment to satisfy the users can be seen in the real network due to the modification costs. In the current age, the existence of network with different radio access technologies has created a heterogeneous environment. Moreover, the mobile hosts available to users are becoming more sophisticated, which opens the opportunity for end-point approaches to alleviate the deployment issues. Furthermore, real-time applications such as VoIP and video conference are delay and quality sensitive, but not much research has considered qualitative requirement. Hence, a suitable technique is needed to alleviate the deployment issues as well as to cope with the stringent requirements of real-time applications. This paper presents a new end-point centric handover approach based on the ant colony probabilistic equation that utilizes the received signal strength and the mean opinion score to trigger the handover. Some simulations were conducted using OMNeT++ to measure the effectiveness of the proposed approach comparing with an existing method, the Endpoint Centric Handover (ECHO). The results show that the proposed approach has better performance compared to the ECHO.

Background (BG) traffic generated automatically by applications or the operating system on devices is delay-insensitive traffic as it does not immediately affect user experiences. However, this traffic may significantly contend network resources with foreground (FG) traffic which conveys data/content to users. This contention directly affects the QoS and QoE of network services, specifically at the peak times. This paper proposes an integration approach to which delay-insensitive traffic is quickly detected and effectively transferred in accordance with the network conditions hence the best resources are yielded to FG traffic. For the traffic transferring, we propose two methods namely the router centric (RC) and the SDN-based approaches. In the RC method, the edge routers analyze network conditions, compute the suggested sending rates for individual traffic flows and send these values back to clients where the adjustment mechanisms are implemented. In the SDN-based method the course of actions for each traffic flow is computed by a remote controller. Experimental results reveal the effectiveness and the feasibility of the proposed approaches.

MathScheme is a long-range research project being conducted at McMaster University with the aim to develop a mechanized mathematics system in which formal deduction and symbolic computation are integrated from the lowest level. The novel notion of a biform theory that is a combination of an axiomatic theory and an algorithmic theory is used to integrate formal deduction and symbolic computation into a uniform theory. A major focus of the project has currently been on building a library of formalized mathematics called the MathScheme Library. The MathScheme Library is based on the little theories method in which a portion of mathematical knowledge is represented as a network of biform theories interconnected via theory morphisms. In this thesis, we describe a systematic explanation of the underlying techniques which have been used for the construction of the MathScheme Library. Then we describe several algebraic constructions that can derive new useful machinery by leveraging the information extracted from a theory. For instance, we show a construction that can reify the term algebra of a (possibly multi-sorted) theory as an inductive data type. Master of Science (MSc)

Conventional frequent pattern mining algorithms require users to specify some minimum support threshold. If that specified-value is large, users may lose interesting information. In contrast, a small minimum support threshold results in a huge set of frequent patterns that users may not be able to screen for useful knowledge. To solve this problem and make algorithms more user-friendly, an idea of mining the k-most interesting frequent patterns has been proposed. This idea is based upon an algorithm for mining frequent patterns without a minimum support threshold, but with a k number of highest frequency patterns. In this paper, we propose an explorative mining algorithm, called ExMiner, to mine k-most interesting (i.e. top-k) frequent patterns from large scale datasets effectively and efficiently. The ExMiner is then combined with the idea of “build once mine anytime” to mine top-k frequent patterns sequentially. Experiments on both synthetic and real data show that our proposed methods are more efficient compared to the existing ones.

Experimental plasma discharges in linear PANTA device are studied by Mach probe measurements, providing floating potential, ion saturation current, and parallel flow velocity time evolution, at different radii of the device. Spectral analysis indicates that drift waves and D'Angelo modes exist simultaneously in the plasma. A discrimination study shows they are located at different positions in radius and frequency. (C) 2017 The Japan Society of Plasma Science and Nuclear Fusion Research

Within the range of plasma shapes and plasma currents investigated, the electron confinement time, Tau_E increases with density, elongation and negative triangularity (-0.4

The effects of plasma shape on confinement and sawtooth stability are studied for positive and negative discharge triangularity and for different elongations with 1.5 MW centrally deposited ECH power

Basic wave-particle interaction dynamics from linear to chaotic regimes is experimentally studied on a frequency tunable gyrotron generating THz radiation in continuous mode (200W) at 263GHz which will be used for dynamic nuclear polarization nuclear magnetic resonance spectroscopy applications. In the studied system, the nonlinear dynamics associated to the waveparticle interaction is dominated by longitudinal mode competition of a given transverse TEm;p cavity-mode. This study covers a wide range of control parameter from gyro-traveling wave tube (gyro-TWT) to gyro-backward wave oscillator (gyro-BWO) like interactions for which extensive theoretical studies have been performed in the past on a simplified system. Besides the common route to chaos characterized by period doubling, other routes have been identified among which some are characterized by line-width frequency-broadening on the side-bands. The complex nonlinear dynamics is in good agreement with the theory and the experimental results are discussed on the basis of the prediction obtained with the nonlinear time-dependent selfconsistent codes TWANG and EURIDICE both based on a slow-time scale formulation of the self-consistent equations governing the wave-particle dynamics. VC

Within the range of plasma shapes and plasma currents investigated, the electron confinement time, tau_Ee, increases with safety factor, density and negative triangularity similar to the Ohmic heating case. There is little dependence of tau_Ee on the heating location provided power deposition occurs inside the q=1 surface; as power deposition moves out of the inversion surface, tau_Ee decreases. The power-induced energy confinement degradation exponent (tau_Ee~PaP) is as usual: alpha_P ~-0.5. As a general trend, central relaxations decrease in amplitude with increasing qa, P_EC, or negative delta, in a situation where the confinement time increases.