Istanbul Technical University

About: Istanbul Technical University is a education organization based out in Istanbul, Turkey. It is known for research contribution in the topics: Fuzzy logic & Large Hadron Collider. The organization has 12889 authors who have published 25081 publications receiving 518242 citations. The organization is also known as: İstanbul Teknik Üniversitesi & Technical University of Istanbul.

Wind energy potential of Gökçeada Island in Turkey

Abstract: The main objective of the present study is to estimate wind power potential of Gokceada Island in the Northern Aegean Sea in Turkey using the wind data collected at four different locations. Wind data collected over a period of 3 years at Ugurlu and Cinaralti stations and a period of 10 years at Aydincik and National Weather Station. In this regard, wind data collected at 10 and 30 m of height above ground, were extrapolated to 50 m which had been chosen as the wind turbine hub height, using power law. Extrapolated wind data of four stations were represented by Weibull probability density functions to find the wind speed distribution curves. Two Weibull parameters of the wind speed distribution function, shape parameter k (dimensionless) and scale parameter c (m/s) were calculated by the developed Fortran programme on monthly and yearly basis to find the wind profiles. Annual wind speed distributions throughout the Gokceada Island were also obtained using the calculated Weibull probability density function parameters. The suitability of the distributions is judged by the discrepancies between the observed and calculated values of the monthly average wind speed. The results show the general availability of wind energy potential across Gokceada Island.

Search for Displaced Supersymmetry in Events with an Electron and a Muon with Large Impact Parameters

Abstract: A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at root s = 8 TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7 fb(-1). Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-mu final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-mu final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to c tau = 2 cm, excluding masses below 790 GeV at 95% confidence level.

The Magnetospheric Sash and the Cross‐Tail S

Abstract: As revealed in MHD simulation, the magnetospheric sash is a band of weak magnetic field that, for the usual case in which the IMF is approximately perpendicular to the geomagnetic dipole, runs tailward along the high-latitude magnetopause flanks from one dayside cusp to the other, closing via the cross-tail neutral sheet. On the magnetopause flanks, it contains the magnetic separator line, at which all three topological types of field lines meet. Seen in a cross-sectional plane through the near-Earth tail, the magnetospheric sash takes the form of the cross-tail S, a weak-field feature comprised of the tail neutral sheet with diagonally symmetric extensions along the magnetopause flanks connecting it to the separator line. The cross-tail S is evident in the MHD results and in cross-sectional maps based on IMP 8 data. The magnetopause expression of the sash is latent in prior works that described the geometry of antiparallel fields across the magnetopause and the consequent cancellation of the fields within the magnetopause layer. The sash picture bears a strong resemblance to antiparallel merging geometry.

Multi Stage Underwater Sensor Localization Using Mobile Beacons

Abstract: Underwater sensor networks (USN) are used for harsh oceanographic missions where human operation is dangerous or impossible. Localization is essential for USNs. It is required for data tagging, node tracking and position-based routing algorithms. Localization is challenging because Global Positioning System(GPS) is not available in underwater; at the same time, existing GPS-less schemes based on fixed landmarks have high communication cost. Such cost is critical in mobile underwater sensor networks (MUSN), since sensor nodes drift with the ocean currents, thus requiring continuous refresh. In this paper, we propose a multi-stage localization scheme using mobile beacons. The beacons periodically ascent and descent in the water column. When they resurface, they receive new GPS coordinates. Then, they dive to the level of the underwater sensors to advertise these coordinates. In turn, localized sensors become proxy beacons and propagate their own coordinates, etc. This iterative, multi-stage localization is the major innovation of this paper. The goal is to localize the nodes with the smallest number of beacons using proxies instead, yet achieving an adequate accuracy. The major benefit is the reduction in operating costs. Mobility is a critical factor in determining performance. In this paper, performance (i.e., the percentage of localized nodes during a cycle, accuracy, delay and communication cost) is tested in a simulation scenario based on a realistic mobility model. The "meandering current mobility with surface effect" (MCM-SE) model - a composite model combining surface and subsurface currents.