Robust traffic engineering

Phenomenal growth of Internet applications in recent years have made it difficult to forecast traffic patterns. Daily Internet traffic patterns shows that the network is vulnerable to malicious attacks, flash crowds and denial of service attacks (DDoS). In this paper, we present a robust routing technique (RRT) that attempts to deal with both normal routing conditions and transient failures. Our simulation results are compared with OSPF-TE. The key advantage of RRT is its convergence to generate the solution. It converges quickly to produce the simulation result on the family of topologies we consider in this paper. We are aiming to combine the best of proactive and reactive traffic engineering in RRT

Taking Account of Non-Timber Values in Harvest Decisions in the Southern Forest of Tasmania

This paper examines the optimal use of a site containing standing timber, taking account of both timber and non-timber values. It discusses the range of non-timber values yielded by a typical site in the southern forest of Tasmania. Taking that site for illustrative purposes, it calculates the relationships between age of stand, extent of timber and non-timber values, and optimal cutting age, using a spreadsheet model. It finds that for a stand with moderate potential environmental benefits there is a period of its life during which it is optimal to log. This segment narrows, and eventually disappears, as potential environmental benefits increase

Acceptability, feasibility and impact of routine screening to detect undiagnosed HIV infection in 17 - 24-month-old children in the western sub-district of Cape Town

Objectives. To explore the acceptability and feasibility of routine HIV screening in children at primary healthcare clinics and ascertain the prevalence of previously undiagnosed HIV infection in 17 - 24-month-old children accessing curative and routine services.Methods. A survey was conducted in 4 primary health clinics in the western sub-district of Cape Town. Rapid HIV screening of 17 - 24-monthold children was performed for consenting caregiver-child pairs. Data on demographics, child health and antenatal history were collected using questionnaires.Results. During recruitment, 358 children (72%) were tested for HIV infection. Most of the children (95.8%) were accompanied by a parent. The prevalence of reported HIV exposure among children was 21% (107/499). Of these, 3 had previously confirmed HIV infection; 1 was reportedly confirmed by a 6-week HIV test, and the other 2 probably contracted the virus via late postpartum transmission. The overall transmission rate was 3.5% (3/86) and the confirmed proportion of HIV-infected children was 0.8% (3/361). No previously unknown HIV infection was detected.Conclusions. Programmes to prevent mother-to-child transmission are effective, but at-risk infants who test negative at 6 weeks should be monitored for subsequent seroconversion. Parents of HIV-exposed infants are more likely to permit (re)testing of their infants than those whose offspring are not at risk. Routine HIV testing of children is feasible and acceptable at primary level, but may require additional resources to achieve universal coverage. Routine screening at an earlier age may detect previously undiagnosed HIV infection

Surface Roughness and Porosity of Hydrated Cement Pastes

. Seventy-eight graphs were plotted to describe and analyze the dependences of the height and roughness irregularities on the water-to-cement ratio and on the porosity of the cement hydrates. The results showed unambiguously that the water-to-cement ratio or equivalently the porosity of the specimens has a decisive influence on the irregularities of the fracture surfaces of this material. The experimental results indicated the possibility that the porosity or the value of the water-to-cement ratio might be inferred from the height irregularities of the fracture surfaces. It was hypothesized that there may be a similarly strong correlation between porosity and surface irregularity, on the one hand, and some other highly porous solids, on the other, and thus the same possibility to infer porosity from the surfaces of their fracture remnants

Semiclassical evaluation of average nuclear one and two body matrix elements

Thomas-Fermi theory is developed to evaluate nuclear matrix elements averaged on the energy shell, on the basis of independent particle Hamiltonians. One- and two-body matrix elements are compared with the quantal results and it is demonstrated that the semiclassical matrix elements, as function of energy, well pass through the average of the scattered quantum values. For the one-body matrix elements it is shown how the Thomas-Fermi approach can be projected on good parity and also on good angular momentum. For the two-body case the pairing matrix elements are considered explicitly.Comment: 15 pages, REVTeX, 6 ps figures; changed conten

Robust routing

In a network, traffic demands are known with a degree of uncertainty, traffic engineering should take into account the traffic variability. In this research work we focus on the robust routing under changing network conditions. Daily Internet traffic pattern shows that network is vulnerable to malicious attacks, denial of service attacks, worms and viruses. Oblivious routing has a substantially better performance than open shortest path first [OSPF] routing for different level of uncertainty. We propose a theoretical framework for Robust Routing aiming to improve online and offline traffic engineering approaches

Faster Born probability estimation via gate merging and frame optimisation

Outcome probability estimation via classical methods is an important task for validating quantum computing devices. Outcome probabilities of any quantum circuit can be estimated using Monte Carlo sampling, where the amount of negativity present in the circuit frame representation quantifies the overhead on the number of samples required to achieve a certain precision. In this paper, we propose two classical sub-routines: circuit gate merging and frame optimisation, which optimise the circuit representation to reduce the sampling overhead. We show that the runtimes of both sub-routines scale polynomially in circuit size and gate depth. Our methods are applicable to general circuits, regardless of generating gate sets, qudit dimensions and the chosen frame representations for the circuit components. We numerically demonstrate that our methods provide improved scaling in the negativity overhead for all tested cases of random circuits with Clifford+T and Haar-random gates, and that the performance of our methods compares favourably with prior quasi-probability simulators as the number of non-Clifford gates increases

Radiocarbon Date List XI: Radiocarbon Dates from Marine Sediment Cores of the Iceland, Greenland, and Northeast Canadian Arctic Shelves and Nares Strait

Radiocarbon Date List XI contains an annotated listing of 178 AMS radiocarbon dates on samples from marine (169 samples) and lake (9 samples) sediment cores. Marine sediment cores, from which the samples for dating were taken, were collected on the Greenland Shelf, Baffin Bay, and the Eastern Canadian Arctic shelf. About 80% of the marine samples for dating were collected on the SW to N Icelandic shelf. The lake sediment cores were collected in northwestern Iceland. For dating of the marine samples, we submitted molluscs (117 samples), benthic and planktic foraminifera (45 samples), plant macrofauna (3 samples), and one serpulid worm. For dating of the lake cores, we submitted wood (8 samples) and one peat sample. The Conventional Radiocarbon Ages range from 294±9114C yr BP to 34,600±640 14C yr BP. The dates have been used to address a variety of research questions. The dates constrain the timing of high northern latitude late Quaternary environmental fluctuations, which include glacier extent, sea level history, isostatic rebound, sediment input, and ocean circulation. The dates also allowed assessment of the accuracy of commonly used reservoir correction. The samples were submitted by INSTAAR and affiliated researchers