LC-PCN: The Load Control PCN Solution

There is an increased interest of simple and scalable resource provisioning solution for Diffserv network. The Load Control PCN (LC-PCN) addresses the following issues:\ud o Admission Control for real time data flows in stateless Diffserv Domains\ud o Flow Termination: Termination of flows in case of exceptional events, such as severe congestion after re-routing.\ud Admission control in a Diffserv stateless domain is a combination of:\ud o Probing, whereby a probe packet is sent along the forwarding path in a network to determine whether a flow can be admitted based upon the current congestion state of the network\ud o Admission Control based on data marking, whereby in congestion situations the data packets are marked to notify the PCN-egress-node that a congestion occurred on a particular PCN-ingress-node to PCN-egress-node path.\ud \ud The scheme provides the capability of controlling the traffic load in the network without requiring signaling or any per-flow processing in the PCN-interior-nodes. The complexity of Load Control is kept to a minimum to make implementation simple.\u

What is the probability that a random integral quadratic form in nn variables has an integral zero?

We show that the density of quadratic forms in $n$ variables over $\mathbb Z_p$ that are isotropic is a rational function of $p$, where the rational function is independent of $p$, and we determine this rational function explicitly. When real quadratic forms in $n$ variables are distributed according to the Gaussian Orthogonal Ensemble (GOE) of random matrix theory, we determine explicitly the probability that a random such real quadratic form is isotropic (i.e., indefinite). As a consequence, for each $n$, we determine an exact expression for the probability that a random integral quadratic form in $n$ variables is isotropic (i.e., has a nontrivial zero over $\mathbb Z$), when these integral quadratic forms are chosen according to the GOE distribution. In particular, we find an exact expression for the probability that a random integral quaternary quadratic form has an integral zero; numerically, this probability is approximately $98.3\%$.Comment: 17 pages. This article supercedes arXiv:1311.554

Left common carotid artery arising from brachiocephalic trunk and their aberrant course displacing trachea

Bovine arch commonly refer a group of congenital variations in the branches of arch of aorta, in which there is aberrant origin of left common carotid artery. These are usually detected incidentally, however rarely they can cause dysphagia lusoria. We report a case of bovine arch and aberrant left common carotid artery in a 62 years old female who had come with complaint of mild dyspnea. On radiograph there was superior mediastinal widening and shift of trachea to right side. CT scan was advised for further evaluation. On CECT there was only two main branches arised from arch of aorta, brachiocephalic trunk and right subclavian artery. There was aberrant origin of left common carotid artery seen from brachiocephalic trunk. The brachiocephalic trunk was very tortuous and displacing trachea to right side

Mechanisms of rolling contact spalling

The results of a study aimed at analyzing the mechanical material interactions responsible for rolling contact spalling of the 440 C steel, high pressure oxygen turbopump bearings are presented. A coupled temperature displacement finite element analysis of the effects of friction heating under the contact is presented. The contact is modelled as a stationary, heat generating, 2 dimensional indent in an elastic perfectly plastic half-space with heat fluxes up to 8.6 x 10000 KW/m sq comparable to those generated in the bearing. Local temperatures in excess of 1000 C are treated. The calculations reveal high levels of residual tension after the contact is unloaded and cools. Efforts to promote Mode 2/Mode 3 fatigue crack growth under cyclic torsion in hardened 440 C steel are described. Spalls produced on 440 C steel by a 3 ball/rod rolling contact testing machine were studied with scanning microscopy. The shapes of the cyclic, stress strain hysteresis loops displayed by hardened 440 C steel in cyclic torsion at room temperature are defined for the plastic strain amplitudes encountered in rolling/sliding contact. Results of these analyses are discussed in detail

Cryptanalysis of an MPEG-Video Encryption Scheme Based on Secret Huffman Tables

This paper studies the security of a recently-proposed MPEG-video encryption scheme based on secret Huffman tables. Our cryptanalysis shows that: 1) the key space of the encryption scheme is not sufficiently large against divide-and-conquer (DAC) attack and known-plaintext attack; 2) it is possible to decrypt a cipher-video with a partially-known key, thus dramatically reducing the complexity of the DAC brute-force attack in some cases; 3) its security against the chosen-plaintext attack is very weak. Some experimental results are included to support the cryptanalytic results with a brief discuss on how to improve this MPEG-video encryption scheme.Comment: 8 pages, 4 figure

Electrochemical behaviour and validated determination of the anitcancer drug Tamoxifen

The electrooxidative behaviour of tamoxifen (Tam) and 4-hydroxytamoxifen (TamOH) was investigated by cyclic (CV), differential-pulse adsorptive anodic stripping (DPAdAS) and square-wave adsorptive anodic stripping (SWAdAS) voltammetric techniques. The anodic oxidation peak of Tamoxifen was attributed to the cyclization reaction to form the corresponding phenanthrene derivative and the mechanism of oxidation was postulated on the basis of controlled potential electrolysis and isolation of the oxidative product. Oxidative stripping analysis was successfully applied to the determination of tamoxifen in a bulk pharmaceutical formulation, and sensitivity in human urine and serum was validated. The achieved limits of detection (LOD) of bulk tamoxifen were 1.8 × 10 -6 mol L -1 and 2.4 × 10 -6 mol L -1 for DPAdAS and SWAdAS, respectively. The LOD values for tamoxifen in human urine and serum sample analysis were 4.75 × 10 -7 mol L -1 and 2.63 × 10 -7 mol L -1 and 1.98 × 10 -7 mol L -1 and 3.28 × 10 -7 mol L -1 for DPAdAS and SWAdAS, respectively. 4-hydroxytamoxifen is oxidised at more positive potentials than Tamoxifen, separated from the Tamoxifen stripping peak, and its adsorption to the glassy carbon electrode is less pronounced. This affects the ability to determine this important phase I metabolite in serum and urine sample

Functional and radiological outcomes of periacetabular osteotomy for hip dysplasia in patients under fifty years using a minimally invasive approach—a single surgeon series with a minimum follow up of two years

\ua9 The Author(s) 2024. Purpose: We conducted a retrospective analysis of prospectively collected data to evaluate (1) the extent of surgical correction following minimally invasive periacetabular osteotomy, (2) improvements in functional outcomes and any potential predictors for favourable outcome, and (3) complications after minimally invasive periacetabular osteotomy. Methods: A total of 352 minimally invasive periacetabular osteotomy procedures were performed on 312 hip dysplasia patients between 2013 and 2020. Radiological parameters such as lateral centre edge angle, acetabular index, and T\uf6nnis grade of arthritis were calculated. Patients also completed a range of patient reported outcome measures. Wilcoxon signed-rank tests were performed to assess for differences between patient reported outcome measures and radiological outcomes across the follow-up periods. Univariate linear regression and logistic regression were used to assess for predictors of change in functional outcome. Results: Patients had a significant correction in mean lateral centre edge angle from 17.2\ub0 to 35.3\ub0 (p < 0.001) and mean acetabular index from 13.2\ub0 to − 0.82\ub0. At one year follow-up all patient reported outcome measures were significantly greater than their baseline measurements and this improvement was maintained at two years. Changes in patient reported outcome measures were independent of radiological parameters such as change in the lateral centre edge angle and acetabular index, pre-operative T\uf6nnis grade, and patient factors such as age and sex. A total of 5.11% of patients developed post-operative complications, with four requiring posterior column fixation. Four patients (1.12%) needed a total hip replacement. Conclusion: Minimally invasive periacetabular osteotomy is a safe procedure that provides significant functional outcome improvements following surgery at six months which is maintained at two years. More than three-fourths of patients achieved improvement of iHOT-12 score beyond the minimal clinically important difference and more than half of the patients achieved substantial clinical benefit for iHOT-12 score

Non-Hermitian skin effect of dislocations and its topological origin

We demonstrate that dislocations in two-dimensional non-Hermitian systems can give rise to density accumulation or depletion through the localization of an extensive number of states. These effects are shown by numerical simulations in a prototype lattice model and expose a different face of non-Hermitian skin effect, by disentangling it from the need for boundaries. We identify a topological invariant responsible for the dislocation skin effect, which takes the form of a ${\mathbb Z}_2$ Hopf index that depends on the Burgers vector characterizing the dislocations. Remarkably, we find that this effect and its corresponding signature for defects in Hermitian systems falls outside of the known topological classification based on bulk-defect correspondence.Comment: 6+4 pages, 2+2 figure