cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Parametric simulation studies on the wave propagation of solar radio emission: the source size, duration, and position
Creators: name: Zhang, PeiJin
name: Wang, ChuanBing
name: Kontar, Eduard P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The observed features of the radio sources indicate complex propagation effects embedded in the waves of solar radio bursts. In this work, we perform ray-tracing simulations on radio wave transport in the corona and interplanetary region with anisotropic electron density fluctuations. For the first time, the variation of the apparent source size, burst duration, and source position of both fundamental emission and harmonic emission at frequency 35 MHz are simulated as the function of the anisotropic parameter $α$ and the angular scattering rate coefficient $η=ε^2/h_0$, where $ε^2={\langle δn^2\rangle}/{n^2}$ is the density fluctuation level and $h_0$ is its correlation length near the wave exciting site. It is found that isotropic fluctuations produce a much larger decay time than a highly anisotropic fluctuation for fundamental emission. By comparing the observed duration and source size with the simulation results in the parameter space, we can estimate the scattering coefficient and the anisotropy parameter $η= 8.9\times 10^{-5}\, \mathrm{km^{-1}}$ and $α= 0.719$ with point pulse source assumption. Position offsets due to wave scattering and refraction can produce the co-spatial of fundamental and harmonic waves in observations of some type III radio bursts. The visual speed due to the wave propagation effect can reach 1.5\,$c$ for $η= 2.4\times 10^{-4}\, \mathrm{km^{-1}}$ and $α=0.2$ for fundamental emission in the sky plane, accompanying with large expansion rate of the source size. The visual speed direction is mostly identical to the offset direction, thus, for the observation aiming at obtaining the source position, the source centroid at the starting point is closer to the wave excitation point.
description: 19 pages
Noncommutative Riesz theorem and weak Burnside type theorem on twisted conjugacy
Creators: name: Troitsky, Evgenij
Publisher: name: arXiv
Year: 2006
Subjects: subject: Operator Algebras (math.OA)
subject: Functional Analysis (math.FA)
subject: Group Theory (math.GR)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 20Cxx; 22D10; 22D25; 43A30; 46Lxx

description: The present paper consists of two parts. In the first part, we prove a noncommutative analogue of the Riesz(-Markov-Kakutani) theorem on representation of functionals on an algebra of continuous functions by regular measures on the underlying space. In the second part, using this result, we prove a weak version of Burnside type theorem for twisted conjugacy for arbitrary discrete groups.
description: 11 pages, no figures
Group Theoretical Formulation of Quantum Partial Search Algorithm
Creators: name: Korepin, Vladimir E.
name: Vallilo, Brenno C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: Data Structures and Algorithms (cs.DS)
subject: Group Theory (math.GR)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Searching and sorting used as a subroutine in many important algorithms. Quantum algorithm can find a target item in a database faster than any classical algorithm. One can trade accuracy for speed and find a part of the database (a block) containing the target item even faster, this is partial search. An example is the following: exact address of the target item is given by a sequence of many bits, but we need to know only some of them. More generally partial search considers the following problem: a database is separated into several blocks. We want to find a block with the target item, not the target item itself. In this paper we reformulate quantum partial search algorithm in terms of group theory.
description: 12 pages
title: Basislinienbestimmung mit GPS-Daten an Bord TerraSAR-X und TanDEM-X im Hinblick auf die Modellierung der Bahnmanoever
Creators: name: Reinhold, Anton
Publisher: name: Deutsches GeoForschungsZentrum GFZ
Year: 2013

description: Scientific Technical Report STR; 13/12
Joint Extraction of m_s and V_us from Hadronic Tau Decays
Creators: name: Maltman, K.
name: Wolfe, C. E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the simultaneous determination of m_s and V_us from flavor-breaking hadronic tau decay sum rules using weights designed to bring under better control problems associated with the slow convergence of the relevant D=2 OPE series. Much improved stability and consistency is found as compared to the results of conventional analyses based on the ``(k,0) spectral weights''. Results for m_s are in excellent agreement with those of recent strange scalar and strange pseudoscalar sum rule analyses, as well as recent lattice analyses, while those for V_us agree within errors with the output from recent lattice-based Gamma[K_{mu 2}]/Gamma[pi_{mu 2}] and K_{\ell 3}-based analyses. Very significant error reductions are shown to be expected, especially for V_us, once the improved strange spectral data from the B factory experiments becomes available.
description: 12 pages, 4 figures
Welsh Wreck Web Research Project (North Cardigan Bay). On-line research into the Sinking of: SS Kirkby (Steamship)
Creators: name: Davies, Gareth J.S.
Publisher: name: Archaeology Data Service
Year: 2024

description: Welsh Wreck Web Research Project unpublished report series, 1
description: On August 17 1915, the SS Kirkby sailing from Barry Wales to Manchester with a cargo of coal was stopped by the German U-boat U-38 approximately 23 miles WSW of Bardsey Island. The crew abandoned the SS Kirkby which was then torpedoed and sunk by the U-38.
Towards Good Practices in Self-supervised Representation Learning
Creators: name: Appalaraju, Srikar
name: Zhu, Yi
name: Xie, Yusheng
name: Fehérvári, István
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Self-supervised representation learning has seen remarkable progress in the last few years. More recently, contrastive instance learning has shown impressive results compared to its supervised learning counterparts. However, even with the ever increased interest in contrastive instance learning, it is still largely unclear why these methods work so well. In this paper, we aim to unravel some of the mysteries behind their success, which are the good practices. Through an extensive empirical analysis, we hope to not only provide insights but also lay out a set of best practices that led to the success of recent work in self-supervised representation learning.
Optical control of spin coherence in singly charged (In,Ga)As/GaAs quantum dots
Creators: name: Greilich, A.
name: Oulton, R.
name: Zhukov, E. A.
name: Yugova, I. A.
name: Yakovlev, D. R.
name: Bayer, M.
name: Shabaev, A.
name: Efros, Al. L.
name: Merkulov, I. A.
name: Stavarache, V.
name: Reuter, D.
name: Wieck, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Electron spin coherence has been generated optically in n-type modulation doped (In,Ga)As/GaAs quantum dots (QDs) which contain on average a single electron per dot. The coherence arises from resonant excitation of the QDs by circularly-polarized laser pulses, creating a coherent superposition of an electron and a trion state. Time dependent Faraday rotation is used to probe the spin precession of the optically oriented electrons about a transverse magnetic field. Spin coherence generation can be controlled by pulse intensity, being most efficient for (2n+1)pi-pulses.
description: 5 pages, 4 figures
Free evolution on algebras with two states
Creators: name: Anshelevich, Michael
Publisher: name: arXiv
Year: 2008
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 46L53 (Primary); 46L54 (Secondary)

description: The key result in the paper concerns two transformations, Phi(rho, psi) and B_t(psi) on states on the algebra of non-commutative polynomials, or equivalently on joint distributions of d-tuples of non-commuting operators. These transformations are related to free probability: Phi intertwines the action of B_t and the free convolution with the semigroup {rho_t}. The maps {B_t} were introduced by Belinschi and Nica as a semigroup of transformations such that B_1 is the bijection between infinitely divisible distributions in the Boolean and free probability theories. They proved the intertwining property above for a single-variable version of the map Phi and the particular case of the free heat semigroup. The more general two-variable map Phi comes, not from free probability, but from the theory of two-state algebras, also called the conditionally free probability theory, introduced by Bozejko, Leinert, and Speicher. Orthogonality of the c-free versions of the Appell polynomials, investigated in arXiv:0803.4279, is closely related to the single-variable map Phi. On the other hand, more general free Meixner families behave well under all the transformations above, and provide clues to their general behavior. Besides the evolution equation, other results include the positivity of the map Phi and descriptions of its fixed points and range.
description: Remark 10 and comments before Lemma 3 added; statement of Theorem 10 modified
Θαλάσσιοι δρόμοι, λιμάνια και ναυσιπλοΐα στο Αιγαίο της Ύστερης Εποχής του Χαλκού
Creators: name: Λοΐζου, Ευγενία Αναστασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Θαλάσσιοι Δρόμοι και Λιμάνια
Ναυπηγική και Ναυσιπλοΐα
Αιγαίο Ύστερης Εποχής Χαλκού
Sea routes and Ports
Shipbuilding and Navigation
Late Bronze Age Aegean

description: Σκοπός της μεταπτυχιακής εργασίας ήταν να διερευνηθεί το ζήτημα της ναυσιπλοΐας εν γένει στον αιγαιακό χώρο κατά τη διάρκεια της Ύστερης Εποχής του Χαλκού. Καταρχάς μελετήθηκαν οι περιβαλλοντικές μεταβλητές οι οποίες διαμόρφωσαν το θαλασσινό τοπίο και τους θαλάσσιους δρόμους επικοινωνίας για τη 2η χιλιετία π.Χ. Επιπλέον παρουσιάστηκαν, αναλύθηκαν και σχολιάστηκαν τα αρχαιολογικά δεδομένα (γραπτές πηγές, εικονογραφία, ναυάγια) που δίνουν πληροφορίες σχετικά με τη ναυπηγική και τη ναυσιπλοΐα. Έπειτα αναζητήθηκαν τα προϊστορικά λιμάνια του Αιγαίου και πραγματοποιήθηκε η συγκριτική τους εξέταση με τα παράλληλά τους από την ανατολική Μεσόγειο. Τέλος, επιχειρήθηκε η σύνθεση και η ερμηνεία των δεδομένων και παρουσιάστηκαν επίσης νέες ερμηνευτικές προτάσεις και ερευνητικές διεπιστημονικές προσεγγίσεις.
description: The aim of the thesis was to investigate the issue of navigation in general in the Aegean during the Late Bronze Age. In the first place, environmental variables that formed the seascape and maritime communication routes for the 2nd millennium BC were studied. Secondly, the available archaeological evidence (written sources, iconography, shipwrecks) that provide information about shipbuilding and shipping was presented, analyzed and commented. Moreover, the prehistoric Aegean ports were searched and a comparative examination of the parallels from the eastern Mediterranean also took place. Finally, a synthesis and interpretation of the data was attempted and also new proposals and interdisciplinary research approaches were presented.
Holographic DC Conductivity for Backreacted NLED in Massive Gravity
Creators: name: Bi, Shihao
name: Tao, Jun
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work a holographic model with the charge current dual to a general nonlinear electrodynamics (NLED) is discussed in the framework of massive gravity. Massive graviton can breaks the diffeomorphism invariance in the bulk and generates momentum dissipation in the dual boundary theory. The expression of DC conductivities in a finite magnetic field are obtained, with the backreaction of NLED field on the background geometry. General transport properties in various limits are presented, and then we turn to the three of specific NLED models: the conventional Maxwell electrodynamics, the Maxwell-Chern-Simons electrodynamics, and the Born-Infeld electrodynamics, to study the parameter-dependence of in-plane resistivity. Two mechanisms leading to the Mott-insulating behaviors and negative magneto-resistivity are revealed at zero temperature, and the role played by the massive gravity coupling parameters are discussed.
description: 29 pages, 13 figures
The Solar Orbiter mission -- Science overview
Creators: name: Müller, D.
name: Cyr, O. C. St.
name: Zouganelis, I.
name: Gilbert, H. R.
name: Marsden, R.
name: Nieves-Chinchilla, T.
name: Antonucci, E.
name: Auchère, F.
name: Berghmans, D.
name: Horbury, T.
name: Howard, R. A.
name: Krucker, S.
name: Maksimovic, M.
name: Owen, C. J.
name: Rochus, P.
name: Rodriguez-Pacheco, J.
name: Romoli, M.
name: Solanki, S. K.
name: Bruno, R.
name: Carlsson, M.
name: Fludra, A.
name: Harra, L.
name: Hassler, D. M.
name: Livi, S.
name: Louarn, P.
name: Peter, H.
name: Schühle, U.
name: Teriaca, L.
name: Iniesta, J. C. del Toro
name: Wimmer-Schweingruber, R. F.
name: Marsch, E.
name: Velli, M.
name: De Groof, A.
name: Walsh, A.
name: Williams, D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Solar Orbiter, the first mission of ESA's Cosmic Vision 2015-2025 programme and a mission of international collaboration between ESA and NASA, will explore the Sun and heliosphere from close up and out of the ecliptic plane. It was launched on 10 February 2020 04:03 UTC from Cape Canaveral and aims to address key questions of solar and heliospheric physics pertaining to how the Sun creates and controls the Heliosphere, and why solar activity changes with time. To answer these, the mission carries six remote-sensing instruments to observe the Sun and the solar corona, and four in-situ instruments to measure the solar wind, energetic particles, and electromagnetic fields. In this paper, we describe the science objectives of the mission, and how these will be addressed by the joint observations of the instruments onboard. The paper first summarises the mission-level science objectives, followed by an overview of the spacecraft and payload. We report the observables and performance figures of each instrument, as well as the trajectory design. This is followed by a summary of the science operations concept. The paper concludes with a more detailed description of the science objectives. Solar Orbiter will combine in-situ measurements in the heliosphere with high-resolution remote-sensing observations of the Sun to address fundamental questions of solar and heliospheric physics. The performance of the Solar Orbiter payload meets the requirements derived from the mission's science objectives. Its science return will be augmented further by coordinated observations with other space missions and ground-based observatories.
description: 32 pages, 30 figures; accepted for publication in A&A
Welsh Wreck Web Research Project (North Cardigan Bay). On-line research into the wreck of the Koh-I-Noor
Creators: name: Dickinson, Ray
Publisher: name: Archaeology Data Service
Year: 2024

description: Welsh Wreck Web Research Project unpublished report series, 1
description: The famous Koh-I-Noor diamond went on display in London in 1851, but was ordered to be recut a year later by Prince Albert to improve its appearance. In 1853 the more modest sailing Smack Koh-I-Noor was built in Aberdovey and then re-cut, lengthened, a year later into a Ketch rigged schooner for the more practical purpose of serving as a Coaster. This she did for 37 years until she struck the outer end of St Patricks Causeway in 1890 and sank.
Amnestically induced persistence in random walks
Creators: name: Cressoni, J. C.
name: da Silva, M. A. A.
name: Viswanathan, G. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study how the Hurst exponent $α$ depends on the fraction $f$ of the total time $t$ remembered by non-Markovian random walkers that recall only the distant past. We find that otherwise nonpersistent random walkers switch to persistent behavior when inflicted with significant memory loss. Such memory losses induce the probability density function of the walker's position to undergo a transition from Gaussian to non-Gaussian. We interpret these findings of persistence in terms of a breakdown of self-regulation mechanisms and discuss their possible relevance to some of the burdensome behavioral and psychological symptoms of Alzheimer's disease and other dementias.
description: 4 pages, 3 figs, subm. to Phys. Rev. Lett
Coupled heat pulse propagation in two fluid plasmas
Creators: name: Jin, S.
name: Reiman, A. H.
name: Fisch, N. J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Because of the large mass differences between electrons and ions, the heat diffusion in electron-ion plasmas exhibits more complex behavior than simple heat diffusion found in typical gas mixtures. In particular, heat is diffused in two distinct, but coupled, channels. Conventional single fluid models neglect the resulting complexity, and can often inaccurately interpret the results of heat pulse experiments. However, by recognizing the sensitivity of the electron temperature evolution to the ion diffusivity, not only can previous experiments be interpreted correctly, but informative simultaneous measurements can be made of both ion and electron heat channels.
description: 6 pages, 3 figures
Measurement and simulation of the neutron response of the Nordball liquid scintillator array
Creators: name: Reiter, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The response of the liquid scintillator array Nordball to neutrons in the energy range 1.5 < T_n < 10 MeV has been measured by time of flight using a 252Cf fission source. Fission fragments were detected by means of a thin-film plastic scintillator. The measured differential and integral neutron detection efficiencies agree well with predictions of a Monte Carlo simulation of the detector which models geometry accurately and incorporates the measured, non-linear proton light output as a function of energy. The ability of the model to provide systematic corrections to photoneutron cross sections, measured by Nordball at low energy, is tested in a measurement of the two-body deuteron photodisintegration cross section in the range E_gamma=14-18 MeV. After correction the present 2H(gamma,n)p measurements agree well with a published evaluation of the large body of 2H(gamma,p)n data.
description: 20 pages 10 figures, submitted Nucl. Instr. Meth. A
Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change
Creators: name: Ehrlich, Robert
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A theory is described based on resonant thermal diffusion waves in the sun that appears to explain many details of the paleotemperature record for the last 5.3 million years. These include the observed periodicities, the relative strengths of each observed cycle, and the sudden emergence in time for the 100 thousand year cycle. Other prior work suggesting a link between terrestrial paleoclimate and solar luminosity variations has not provided any specific mechanism. The particular mechanism described here has been demonstrated empirically, although not previously invoked in the solar context. The theory also lacks most of the problems associated with Milankovitch cycles.
description: in press with The Journal of Atmospheric and Solr Terrestrial Physics
Formation of regular spatial patterns in ratio-dependent predator-prey model driven by spatial colored-noise
Creators: name: Liu, Quan-Xing
name: Jin, Zhen
Publisher: name: arXiv
Year: 2006
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: Results are reported concerning the formation of spatial patterns in the two-species ratio-dependent predator-prey model driven by spatial colored-noise. The results show that there is a critical value with respect to the intensity of spatial noise for this system when the parameters are in the Turing space, above which the regular spatial patterns appear in two dimensions, but under which there are not regular spatial patterns produced. In particular, we investigate in two-dimensional space the formation of regular spatial patterns with the spatial noise added in the side and the center of the simulation domain, respectively.
description: 4 pages and 3 figures
The Protracted Magmatism and Hydrothermal Activity Associated with the Gibraltar Porphyry Cu-Mo Deposit, South Central British Columbia, Canada.
Creators: name: Kobylinski, Christopher
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2019
Subjects: Zircon
Epidote
Porphyry
Copper
Alteration
U-Pb
Ce anomaly
Eu anomaly
Zoning
Sr/Y
Trace elements in Zircon
Ce4+/Ce3+

description: The Gibraltar porphyry-Cu deposit is a large open pit porphyry Cu mine in Canada with the geological tonnage (production and reserves) of 3.2 Mt Cu. The Gibraltar deposit is hosted by the Granite Mountain Batholith (GMB), a tonalitic batholith with the surface exposure over 150 km2. All rocks within the batholith are tonalites with minor quartz diorites. The batholith intrudes into mafic volcanoclastic rocks of the Nicola group in the Quesnel terrane of the Canadian Cordillera. The Cu mineralization at Gibraltar is confined to a small 4.5 km2 area in the central part of the batholith and occurs primarily as disseminated chalcopyrite. New U-Pb dating on zircon shows protracted late Triassic magmatism spanning ~25 m.y. for the formation of the GMB. Early magmatism is dated at 229.2±4.4 Ma in unmineralized tonalites. Later, at least three magmatism form the Cu mineralization during a period spanning from 218.9±3.1 Ma to 205.8±2.1 Ma. These fertile magmas form in a more mature arc setting, superseded early barren magmatic activity in a more juvenile arc setting for the bulk of the GMB. Epidote in the GMB shows compositional zoning with Fe-poor cores and Fe-rich rims. The zoning in the mineralized intrusions likely reflects changes in hydrothermal fluid, from S-rich to S-poor. The data from the Gibraltar deposit shows that an economic porphyry Cu deposit may be found in igneous rocks with low Sr/Y in bulk rocks and low Eu/Eu* in zircon. In the Gibraltar deposit, Ce anomalies in zircon reflect oxidation conditions and are correlated with Cu resource associated with their respective intrusion.
Magnetically Preferred Solar Longitudes: Reality?
Creators: name: Henney, C. J.
name: Durney, B. R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The observed persistence of specific periodicities detected in time series associated with solar surface magnetic activity over several solar cycles has led to numerous papers supporting the existence of preferred longitudes. Recent analysis of the past 120 years of sunspot number data showed that no observed periodicity remained coherent for durations greater than two 11-year solar cycles. Here we address the question: Could the observed periodicities of solar magnetic signals on time scales of two decades be the result of a purely stochastic process? We begin to answer this by comparing phase coherence between observed periodic signals and signals from a model using longitudinally random eruptions. A surprisingly non-negligible likelihood is found, approximately 1 in 3, that observed periodicities from integrated full-disk solar parameters are a chance occurrence for time series on the order of 20 years in duration.
description: 8 pages, 4 figures, Large-scale structures and their role in solar activity
Hochschild cohomology via incidence algebras
Creators: name: Redondo, Maria Julia
Publisher: name: arXiv
Year: 2006
Subjects: subject: Representation Theory (math.RT)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 16E40, 16G20

description: Given an algebra A we associate an incidence algebra A(Σ) and compare their Hochschild cohomology groups.
description: 16 pages, Section 3.2 deleted, Section 4 added
Simultaneous Magneto-Optical Trapping of Bosonic and Fermionic Chromium Atoms
Creators: name: Chicireanu, R.
name: Pouderous, A.
name: Barbe, R.
name: Laburthe-Tolra, B.
name: Marechal, E.
name: Vernac, L.
name: Keller, J. -C.
name: Gorceix, O.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on magneto-optical trapping of fermionic 53Cr atoms. A Zeeman-slowed atomic beam provides loading rates up to 3 10^6 /s. We present systematic characterization of the magneto-optical trap (MOT). We obtain up to 5 10^5 atoms in the steady state MOT. The atoms radiatively decay from the excited P state into metastable D states, and, due to the large dipolar magnetic moment of chromium atoms in these states, they can remain magnetically trapped in the quadrupole field gradient of the MOT. We study the accumulation of metastable 53Cr atoms into this magnetic trap. We also report on the first simultaneous magneto-optical trapping of bosonic 52Cr and fermionic 53Cr atoms. Finally, we characterize the light assisted collision losses in this Bose-Fermi cold mixture.
description: 8 pages, 5 figures. submitted to Phys Rev A
Aquatic environment protection in protected areas: a comparative study
Creators: name: Spyksma, John Randall
Publisher: name: University of British Columbia
Year: 2009

description: Protected areas are established to preserve representative natural ecosystems and pristine environments and to provide opportunities for recreation. Water is critical to ecological processes and so must be an important factor in protected area management. Despite the importance of water to protected area integrity, the protection of the aquatic environment has been given very little consideration when compared to terrestrial environments. This lack of consideration for the management and protection of the aquatic environment is evident in the protected areas of British Columbia and Thailand. Methods have been developed to help ensure the protection of the environments within protected areas. These methods fall short of giving the aquatic environment due consideration. In addition, managers have very little guidance or mandate to address external threats to the aquatic environment within protected areas. This deficiency is critical as external threats to protected areas will continue to intensify. Recommendations are made to improve the protection of the aquatic environment within and entering protected areas. These recommendations include the improved use of present protection activities such as use permits, visitor management, and general management planning. In addition, more comprehensive land use planning, the use of public trust and instream flow legislation, and possible corridor protection programs are examined to improve the protection of the aquatic environment in protected areas. Monitoring plays an important role in the protection of the aquatic environment in protected areas, but was lacking in Thailand. Monitoring efforts in B.C. protected areas could benefit from increased coordination. A framework is developed to guide protected area managers in the development of aquatic environment monitoring programs.
C^1 actions of the mapping class group on the circle
Creators: name: Parwani, Kamlesh
Publisher: name: arXiv
Year: 2008
Subjects: subject: Dynamical Systems (math.DS)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 37E10

description: Let S be a connected orientable surface with finitely many punctures, finitely many boundary components, and genus at least 6. Then any C^1 action of the mapping class group of S on the circle is trivial. The techniques used in the proof of this result permit us to show that products of Kazhdan groups and certain lattices cannot have C^1 faithful actions on the circle. We also prove that for n > 5, any C^1 action of Aut(F_n) or Out(F_n) on the circle factors through an action of Z/2Z.
description: 9 pages
The Mott insulator transition in two dimensions
Creators: name: Spielman, I. B.
name: Phillips, W. D.
name: Porto, J. V.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Cold atoms confined in periodic potentials are remarkably versatile quantum systems for implementing simple models prevalent in condensed matter theory. In the current experiment, we realize the 2D Bose-Hubbard model by loading a Bose-Einstein condensate into an optical lattice, and we study the resulting Mott insulating state (a phase of matter in which atoms are localized on specific lattice sites). We measure momentum distributions which agree quantitatively with theory (no adjustable parameters). We also study correlations in atom shot nose and observe a pronounced dependence on the lattice depth, this dependence indicates geometric effects to first order and suggests deviations due to higher order corrections.
description: Expanded version of text accepted for publication in PRL. Changes: significant textual improvement, and corrected numerical transcription errors relevant to Figs 1. and 4
An Interpretation of Flat Density Cores of Clusters of Galaxies by Degeneracy Pressure of Fermionic Dark Matter: A Case Study of Abell 1689
Creators: name: Nakajima, Tadashi
name: Morikawa, Masahiro
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Flat density cores have been obtained for a limited number of clusters of galaxies by strong gravitational lensing. This paper explores the possibility that the degeneracy pressure of fermionic dark matter accounts for the flat top density profiles. This is a case study of A1689 for which the density profile has been obtained from the inner region out to 1Mpc by the combination of strong and weak lensing. In the case that the dark matter consists of the mixture of degenerate relic neutrinos and collisionless cold dark matter particles, the acceptable mass range for relic neutrinos is between 1 and 2 eV, if the ratio of the two kinds of dark matter particles is fixed to its cosmic value.
description: Accepted for Publication in ApJ. Companion paper to astro-ph/0607097
Tree Automata for Extracting Consensus from Partial Replicas of a Structured Document
Creators: name: Tchendji, Maurice Tchoupé
name: Ndadji, Milliam Maxime Zekeng
Publisher: name: arXiv
Year: 2020
Subjects: subject: Formal Languages and Automata Theory (cs.FL)
subject: Information Theory (cs.IT)
subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: In an asynchronous cooperative editing workflow of a structured document, each of the co-authors receives in the different phases of the editing process, a copy of the document to insert its contribution. For confidentiality reasons, this copy may be only a partial replica containing only parts of the (global) document which are of demonstrated interest for the considered co-author. Note that some parts may be a demonstrated interest over a co-author; they will therefore be accessible concurrently. When it's synchronization time (e.g. at the end of an asynchronous editing phase of the process), we want to merge all contributions of all authors in a single document. Due to the asynchronism of edition and to the potential existence of the document parts offering concurrent access, conflicts may arise and make partial replicas unmergeable in their entirety: they are inconsistent, meaning that they contain conflictual parts. The purpose of this paper is to propose a merging approach said by consensus of such partial replicas using tree automata. Specifically, from the partial replicas updates, we build a tree automaton that accepts exactly the consensus documents. These documents are the maximum prefixes containing no conflict of partial replicas merged.
Πιθανοκρατικός Έλεγχος Μοντέλων με το Prism:Ανάλυση του πρωτοκόλλου Elliptic Curve Diffie Helman σε ασύρματα δίκτυα αισθητήρων
Creators: name: Στεργιοπούλου, Ευαγγελία Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Πιθανοκρατικός Έλεγχος Μοντέλων
Ελεγκτής Μοντέλων Prism
Πρωτόκολλο Elliptic Curve Diffie Helman
Probabilistic Model Checking
Prism Model Checker
Elliptic Curve Diffie Helman Protocol

description: Ένας πολύ σημαντικός και δυναμικά αναπτυσσόμενος τομέας της πληροφορικής στις μέρες μας είναι ο έλεγχος μοντέλων. Για αυτό το σκοπό έχουν αναπτυχθεί μέχρι στιγμής διάφορα εργαλεία, ένα εκ των οποίων είναι και το εργαλείο prism. Πρόκειται για ένα σχετικά νέο και αξιόλογο εργαλείο ελέγχου μοντέλων το οποίο χρησιμοποιείται για να αναλύσει και να μοντελοποιήσει συστήματα που παρουσιάζουν συμπεριφορά σχετική με πιθανότητες. Τα πρωτόκολλα επικοινωνίας αποτελούν ένα είδος τέτοιων συστημάτων προς μοντελοποίηση. Με τη χρήση του εργαλείου prism, για παράδειγμα, μπορεί να δημιουργηθεί ένα ακριβές μοντέλο το οποίο θα αναπαριστά τη συμπεριφορά ενός πρωτοκόλλου επικοινωνίας, με σκοπό τη μελέτη των χαρακτηριστικών αλλά και των αδυναμιών που μπορεί αυτό να κρύβει. Στη συγκεκριμένη διπλωματική εργασία χρησιμοποιείται το εργαλείο prism για να ελεγχθεί το μοντέλο που αναπαριστά τη συμπεριφορά του κρυπτογραφικού πρωτοκόλλου ECDH (Elliptic Curve Diffie Helman), όταν εφαρμόζεται πάνω σε ασύρματα δίκτυα αισθητήρων. Εκτελείται πιθανοκρατικός έλεγχος (probabilistic model checking) στο μοντέλο του πρωτοκόλλου και εξάγονται ποσοτικά αποτελέσματα σχετικά με την πιθανότητα πραγματοποίησης της εγκαθίδρυσης ενός κοινού μυστικού κλειδιού μεταξύ δύο αισθητήριων κόμβων ενός δικτύου καθώς και αποτελέσματα που αφορούν τα συνολικά ενεργειακά τους κόστη.
description: Nowadays, a very important and dynamically developing domain of computer science is model checking. For this purpose several tools have been developed until now, one of which is the prism tool. It is about a new and significant checking tool. The main use of it is the analysis and the modeling of probabilistic systems. Communication protocols are a kind of such systems. Prism tool can be used for many reasons, one of which is the creation of an exact model that depicts the behavior of a communication protocol. The purpose of it is not only to study protocol’s characteristics but also to discover its inadequacies. In this thesis is used the prism tool in order to test the model that represents the behavior of the cryptographic protocol ECDH , when it is applied on wireless sensor networks. Also, performed probabilistic model checking in the model of the protocol and exported quantitative results on the likelihood of the establishment of a common secret key between two nodes of a sensor network, and results in concerning the overall energy costs.
A High-Abundance Arc in the Compact Group of Galaxies HCG 62: An AGN- or Merger-Induced Metal Outflow?
Creators: name: Gu, Junhua
name: Xu, Haiguang
name: Gu, Liyi
name: An, Tao
name: Wang, Yu
name: Zhang, Zhongli
name: Wu, Xiang-Ping
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present a Chandra study of the metal distribution in the X-ray bright compact group of galaxies HCG 62. We find that the diffuse X-ray emission is peaked at the core of the central galaxy NGC 4778, and is dominated by the contribution of the hot gas. The diffuse emission is roughly symmetric within \simeq0.25^{\prime}, which is straddled by double-sided X-ray cavities aligned in the northeast-southwest direction. By mapping the emission hardness ratio distributions and by performing the 2-dimensional spectral analysis, we identify a remarkable high-abundance arc region at about 2^{\prime} (33.6h_{70}^{-1} kpc) from the X-ray peak that spans over a vast region from south to northwest, a part of which roughly coinciding with the outer edge of the southwest X-ray cavity. The measured average abundance in this arc is higher than that in its neighboring regions by a factor of about 2, and the abundance ratios therein are nicely consistent with the dominance of the SN Ia yields. We estimate that the mass of iron contained in the arc is >3\times 10^{6}h_{70}^{-2.5} solar mass, which accounts for >3% of the iron synthesized in the galaxy. The high-abundance arc could have been formed by the AGN activities. However, it is also possible that the arc was formed in a recent merger as is implied by the recent optical kinematic study (Spavone et al. 2006), which implies that mergers may be as important as AGN activities in metal redistributions in early-type galaxies and their associated groups or clusters.
description: 20 pages, 5 figures, accepted for publication in ApJ
Κινούμενα Συστήματα Χαρτογράφησης - Αποτύπωση με το Leica Pegasus One Τμήματος Οδού Στο Πολεοδομικό Συγκρότημα Θεσσαλονίκης
Creators: name: Καραχάλιου, Ελένη Στέφανου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Κινούμενα Συστήματα Χαρτογράφησης
Σύστημα Leica Pegasus One
Αστικό Οδικό Δίκτυο
Mobile Mapping Systems
Leica Pegasus One MMS
Urban road network

description: Η τεχνολογία των Κινούμενων Συστημάτων Χαρτογράφησης, βρίσκεται στο προσκήνιο τα τελευταία χρόνια. Η ψηφιακή απεικόνιση σε συνδυασμό με την άμεση γεωαναφορά, καθιστά τα εν λόγω συστήματα αποτελεσματικά εργαλεία για τη συλλογή γεωχωρικών δεδομένων, παρέχοντας λύσεις για μία ταχεία και αποδοτική χαρτογράφηση υψηλής ακρίβειας. Σκοπός της παρούσας διπλωματικής εργασίας είναι, αφού μελετηθεί η εξέλιξη των συστημάτων κινούμενης χαρτογράφησης και κατανοηθεί η λειτουργίας τους, να πραγματοποιηθεί αποτύπωση με το σύστημα Leica Pegasus One, σε αστικό ιστό και να διερευνηθούν τα αποτελέσματα που μπορούν να προκύψουν χρησιμοποιώντας ποικίλα λογισμικά. Από τη διαδρομή που καταγράφηκε εντός του Πολεοδομικού Συγκροτήματος Θεσσαλονίκης, επιλέχθηκε τμήμα του οδικού δικτύου και υλοποίηθηκαν τρεις εφαρμογές. Αρχικά δημιουργήθηκε ένα ολοκληρωμένο Γεωγραφικό Σύστημα Πληροφοριών (GIS) για το τμήμα του αστικού οδικού δικτύου που επιλέχθηκε. Στη συνέχεια, η πληροφορία που συλλέχθηκε, χρησιμοποίηθηκε για τη δημιουργία σχεδίων μηκοτομής και διατομών για το τμήμα της οδού, με τη χρήση λογισμικού οδοποιίας. Τέλος, μελετήθηκαν οι δυνατοί τρόποι επεξεργασίας των Lidar δεδομένων για την τρισδιάστατη μοντελοποίηση όψεων των κτιρίων και την παραγωγή ψηφιακού μοντέλου εδάφους.
description: Mobile Mapping Technology has been rapidly developed in the recent years. Digital imaging combined with direct georeferencing, make these systems efficient tools for collecting geospatial data and provide solutions for a fast and efficient high-precision mapping. The aim of this thesis, is to collect geospatial and Lidar data, using the Leica Pegasus One MMS, in the urban environment of Thessaloniki and to evaluate the results by using different software. A road section was selected and performed three applications. At first, an integrated Geographic Information System (GIS) was created, for the selected part of the urban road network. Then, the information collected, was used to create the profile sections of the road by using an appropriate road software. Finally, possible ways of processing Lidar data for three dimensional modeling facades and producing digital terrain model, were investigated.
Modeling the Broadband Spectral Energy Distribution of the Microquasars XTE J1550-564 and H 1743-322
Creators: name: Xue, Yongquan
name: Wu, Xue-Bing
name: Cui, Wei
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report results from a systematic study of the spectral energy distribution (SED) and spectral evolution of XTE J1550--564 and H 1743--322 in outburst. The jets of both sources have been directly imaged at both radio and X-ray frequencies, which makes it possible to constrain the spectrum of the radiating electrons in the jets. We modelled the observed SEDs of the jet `blobs' with synchrotron emission alone and with synchrotron emission plus inverse Compton scattering. The results favor a pure synchrotron origin of the observed jet emission. Moreover, we found evidence that the shape of the electron spectral distribution is similar for all jet `blobs' seen. Assuming that this is the case for the jet as a whole, we then applied the synchrotron model to the radio spectrum of the total emission and extrapolated the results to higher frequencies. In spite of significant degeneracy in the fits, it seems clear that, while the synchrotron radiation from the jets can account for nearly 100% of the measured radio fluxes, it contributes little to the observed X-ray emission, when the source is relatively bright. In this case, the X-ray emission is most likely dominated by emission from the accretion flows. When the source becomes fainter, however, the jet emission becomes more important, even dominant, at X-ray energies. We also examined the spectral properties of the sources during outbursts and the correlation between the observed radio and X-ray variabilities. The implication of the results is discussed.
description: 9 pages, 11 figures, MNRAS, accepted; the paper has been much expanded (e.g., arguments strengthened, another source H 1743-322 added) and rewritten (e.g., title changed, abstract revised); the main conclusions remain unchanged
On the damping of the angular momentum of three harmonic oscillators
Creators: name: Isar, A.
name: Sandulescu, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In the frame of the Lindblad theory of open quantum systems, the system of three uncoupled harmonic oscillators with opening operators linear in the coordinates and momenta of the considered system is analyzed. The damping of the angular momentum and of its projection is obtained.
description: 8 pages
Measurement of the Surface Gravity of $η$ Boo
Creators: name: van Belle, Gerard T.
name: Ciardi, David R.
name: Boden, Andrew F.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Direct angular size measurements of the G0IV subgiant $η$ Boo from the Palomar Testbed Interferometer are presented, with limb-darkened angular size of $θ_{LD}= 2.1894^{+0.0055}_{-0.0140} $ mas, which indicate a linear radius of $R=2.672 \pm 0.028 R_\odot$. A bolometric flux estimate of $F_{BOL} = 22.1 \pm 0.28\times 10^{-7}$ erg cm$^{-2}$s$^{-1}$ is computed, which indicates an effective temperature of $T_{EFF}=6100 \pm 28$ K and luminosity of $L = 8.89 \pm 0.16 L_\odot$ for this object. Similar data are established for a check star, HD 121860. The $η$ Boo results are compared to, and confirm, similar parameters established by the {\it MOST} asteroseismology satellite. In conjunction with the mass estimate from the {\it MOST} investigation, a surface gravity of $\log g=3.817 \pm 0.016$ [cm s$^{-2}$] is established for $η$ Boo.
description: To appear in March 1, 2007 ApJ v657 n1
New Insights into Time Series Analysis IV: Panchromatic and Flux Independent Period Finding Methods
Creators: name: Lopes, C. E. Ferreira
name: Cross, N. J. G.
name: Jablonski, F.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: New time-series analysis tools are needed in disciplines as diverse as astronomy, economics and meteorology. In particular, the increasing rate of data collection at multiple wavelengths requires new approaches able to handle these data. The panchromatic correlated indices $K^{(s)}_{(fi)}$ and $L^{(s)}_{(pfc)}$ are adapted to quantify the smoothness of a phased light-curve resulting in new period-finding methods applicable to single- and multi-band data. Simulations and observational data are used to test our approach. The results were used to establish an analytical equation for the amplitude of the noise in the periodogram for different false alarm probability values, to determine the dependency on the signal-to-noise ratio, and to calculate the yield-rate for the different methods. The proposed method has similar efficiency to that found for the String Length period method. The effectiveness of the panchromatic and flux independent period finding methods in single waveband as well as multiple-wavebands that share a fundamental frequency is also demonstrated in real and simulated data.
description: 14 pages, 7 figures
Radio Frequency Speed Bumps for Near-Zero Speed Zone Control in Nigeria
Creators: name: Agbolade, Olaide Ayodeji
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Over speeding is an important problem in Nigeria. The Nigerian Federal Road Safety Commission report shows that over speeding is directly responsible for over 50 percent of road crashes in the country. Speed bumps particularly on highways have not proved to be the solution; they rather contribute more to the problem. Based the advent of the dedicated short range communications (DSRC) systems defined by the IEEE 802.11p standard, we proposed a radio frequency based speed bump to mimic the operation of traditional speed breakers. The model consists of a roadside unit and an in-vehicle unit that works with the already installed speed limiter in vehicles. In our work, we showed that the RF based model is able to decelerate the vehicle at a recommended rate of 10 m/s2 over a convenient stopping distance of 80 m. Our work also showed that signal strength based adaptive speed limiter systems can be used as a reliable substitute to GPS thus eradicating the need for additional hardware in the design.
description: 8 pages,7 figures, Peer review Journal paper