Analysis of telephone network traffic based on a complex user network

The traffic in telephone networks is analyzed in this paper. Unlike the classical traffic analysis where call blockings are due to the limited channel capacity, we consider here a more realistic cause for call blockings which is due to the way in which users are networked in a real-life human society. Furthermore, two kinds of user network, namely, the fully-connected user network and the scale-free network, are employed to model the way in which telephone users are connected. We show that the blocking probability is generally higher in the case of the scale-free user network, and that the carried traffic intensity is practically limited not only by the network capacity but also by the property of the user network.Comment: 17 pages, 9 figures, accepted for Physica

Critical points of Wang-Yau quasi-local energy

In this paper, we prove the following theorem regarding the Wang-Yau quasi-local energy of a spacelike two-surface in a spacetime: Let $\Sigma$ be a boundary component of some compact, time-symmetric, spacelike hypersurface $\Omega$ in a time-oriented spacetime $N$ satisfying the dominant energy condition. Suppose the induced metric on $\Sigma$ has positive Gaussian curvature and all boundary components of $\Omega$ have positive mean curvature. Suppose $H \le H_0$ where $H$ is the mean curvature of $\Sigma$ in $\Omega$ and $H_0$ is the mean curvature of $\Sigma$ when isometrically embedded in $R^3$. If $\Omega$ is not isometric to a domain in $R^3$, then 1. the Brown-York mass of $\Sigma$ in $\Omega$ is a strict local minimum of the Wang-Yau quasi-local energy of $\Sigma$, 2. on a small perturbation $\tilde{\Sigma}$ of $\Sigma$ in $N$, there exists a critical point of the Wang-Yau quasi-local energy of $\tilde{\Sigma}$.Comment: substantially revised, main theorem replaced, Section 3 adde

What Goes Up, Shouldn't Come Down: Learning from Construction and Engineering Failures

Design errors can severely jeopardize safety and contribute to failures in construction and engineering projects. Such failures can have devastating economic, environmental and social consequences. Significant efforts have been made to reduce the incidence of failures through learning from previous disasters and events by modifying building and engineering codes and standards accordingly. Design errors, however, remain an innate feature of construction and engineering projects. Most errors are identified during construction and require rework, but there is always a potential for some to remain undetected and contribute to failure, and as a result potentially contribute to accidents and loss of life. This paper examines the circumstances and issues that contributed to a series of construction and engineering failures, to enable development of a systemic learning framework to contain and reduce design errors and potential failures and accidents

Measurement of Cosmic-ray Muon-induced Spallation Neutrons in the Aberdeen Tunnel Underground Laboratory

AbstractMuon-induced neutrons are one of the major backgrounds to various underground experiments, such as dark matter searches, low-energy neutrino oscillation experiments and neutrino-less double beta-decay experiments. Previous experiments on the underground production rate of muon-induced neutrons were mostly carried out either at shallow sites or at very deep sites. The Aberdeen Tunnel experiment aims to measure the neutron production rate at a moderate depth of 611 meters water equivalent. Our apparatus comprises of six layers of plastic-scintillator hodoscopes for tracking the incident cosmic-ray muons, and 760 L of gadolinium-doped liquid-scintillator for both neutron production and detection targets. In this paper, we describe the design and the performance of the apparatus. The preliminary result on the measurement of neutron production rate is also presented

Assessing trace-element mobility in Algeciras Bay (Spain) sediments by acid and complexing screening

Acetic acid (HOAc) and diethylenetriaminepentaacetic acid (DTPA) single extraction agents were evaluated as screening methods to estimate the mobility of some trace elements in coastal sediments from Algeciras Bay. Sediments’ total metal concentrations of most heavy metals were found to be high around the areas impacted by anthropogenic activities such a sewage, atmospheric deposition and industrial activities, with notable values for As, Ni, Cr, Pb and Cd. The order of significant extraction efficiencies obtained with DTPA, were as follows: Pb (25.65%), Cu (19.78%), Cd (14.80%) and Zn (11.25%), while those obtained with HOAc were: Mn (33.00%), Tl (24.88%), Pb (18.99%), Cd (13.59%) and Co (11.78%). The comparison between the risk assessment codes (RAC) and the percent metal extractable fractions provided results of serious concern. Very high risk values of Cu, Zn, Cd and Pb extracts in DTPA were observed near the metallurgical industry, with Mn and Tl in HOAc extracts showing high risk values near the same industrial area and harbour activities. Sediments’ total metal concentrations were compared with the Low Alert-Level (LAL) sediment quality guidelines, where Co, Pb, Zn and Ni in both extractants and Cd and Cu in DTPA as well as Tl extracted in HOAc exceeded the LAL values respectively. The Spearman Rank test showed positive correlations between Co, Cu, Ni and Zn in DTPA extracts and their corresponding total metal concentrations, with Co, Cr, Fe, Ni, Tl and Zn in HOAc and total concentrations showing positive correlations. Furthermore, higher positive correlations were found between both extraction methods for Co (q= 0.797), Cu (q = 0.777), Ni (q = 0.789) and Zn (q = 0.942), indicating comparable potential extraction efficiencies between these extractants for these metals in the sediment studied

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Test beam performance measurements for the Phase I upgrade of the CMS pixel detector

A new pixel detector for the CMS experiment was built in order to cope with the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking with a reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and allows operation at low comparator thresholds. In this paper, comprehensive test beam studies are presented, which have been conducted to verify the design and to quantify the performance of the new detector assemblies in terms of tracking efficiency and spatial resolution. Under optimal conditions, the tracking efficiency is (99.95 ± 0.05) %, while the intrinsic spatial resolutions are (4.80 ± 0.25) μm and (7.99 ± 0.21) μm along the 100 μm and 150 μm pixel pitch, respectively. The findings are compared to a detailed Monte Carlo simulation of the pixel detector and good agreement is found.Peer reviewe