57 research outputs found
Root-Hadamard transforms and complementary sequences
In this paper we define a new transform on (generalized) Boolean functions,
which generalizes the Walsh-Hadamard, nega-Hadamard, -Hadamard,
consta-Hadamard and all -transforms. We describe the behavior of what we
call the root- Hadamard transform for a generalized Boolean function in
terms of the binary components of . Further, we define a notion of
complementarity (in the spirit of the Golay sequences) with respect to this
transform and furthermore, we describe the complementarity of a generalized
Boolean set with respect to the binary components of the elements of that set.Comment: 19 page
A quantum algorithm to estimate the Gowers norm and linearity testing of Boolean functions
We propose a quantum algorithm to estimate the Gowers norm of a Boolean
function, and extend it into a second algorithm to distinguish between linear
Boolean functions and Boolean functions that are -far from the set of
linear Boolean functions, which seems to perform better than the classical BLR
algorithm. Finally, we outline an algorithm to estimate Gowers norms of
Boolean functions
Trace element contamination in the arms of the Danube Delta (Romania/Ukraine): Current state of knowledge and future needs
This paper provides the first critical synopsis of contamination by selected trace elements in the whole
Danube Delta (Romania/Ukraine) to: identify general patterns of contamination by trace elements across
the Delta, provide recommendations to refine existing monitoring networks and discuss the potential
toxicity of trace elements in the whole Delta. Sediment samples were collected between 2004 and 2007
in the three main branches of the Delta (Chilia, Sulina and Sfantu Gheorghe) and in the secondary delta of
the Chilia branch. Samples were analyzed for trace elements (Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) and TiO2,
Fe2O3, MnO, CaCO3 and total organic carbon. Cluster analysis (CA) and Principal Component Analysis
(PCA) showed that levels of Cd, Cu, Pb, and Zn were influenced by anthropogenic activities. At the
opposite, concentrations of Cr and Ni largely originated from the weathering of rocks located in the
Romanian part of the Danube catchment and naturally rich in these elements. Data analysis using Self-
Organizing Maps confirmed the conclusions of CA/PCA and further detected that the contamination
tended to be higher in the Chilia and Sulina arms than in the Sfantu Gheorghe arm. The potential
ecological risks due to trace element contamination in the Danube Delta could be identified as moderate
and localized, provided that the presence of the natural sources of Cr and Ni was properly considered.
The available results suggest that monitoring sediment quality at the mouths of Sulina and Sfantu
Gheorghe arms is probably enough to get a picture of the sediment quality along their entire lengths.
However, a larger network of monitoring points is necessary in the Chilia and secondary Chilia delta to
account for the presence of local point sources and for the more complex hydrodynamic of this part of
the Danube Delta
A quantum algorithm to estimate the closeness to the Strict Avalanche criterion in Boolean functions
We propose a quantum algorithm (in the form of a quantum oracle) that
estimates the closeness of a given Boolean function to one that satisfies the
``strict avalanche criterion'' (SAC). This algorithm requires queries of
the Boolean function oracle, where is the number of input variables, this
is fewer than the queries required by the classical algorithm to perform the
same task. We compare our approach with other quantum algorithms that may be
used for estimating the closeness to SAC and it is shown our algorithm verifies
SAC with the fewest possible calls to quantum oracle and requires the fewest
samples for a given confidence bound
Multiferroic (Nd,Fe)-doped PbTiO3 ceramics with coexistent ferroelectricity and magnetism at room temperature
We report the structural, dielectric, elastic, ferroelectric and ferromagnetic properties of multiferroic (Nd, Fe)-doped PbTiO3 perovskite ceramics with composition (Pb 0.88 Nd 0.08 )(Ti 0.94 Fe 0.04 Mn 0.02 )O 3 , prepared by different solid state reaction methods: the first one based on a single-stage calcination (Method I) and the second based on a double-stage calcination (Method II). Structural, dielectric and anelastic measurements evidenced a double phase transition for samples prepared by Method I, which has been attributed to phase separation. This phase separation has been confirmed also by TEM and HRTEM investigations. Samples prepared by Method II showed a single phase transition from paraelectric to ferroelectric phase. We found coexistent ferroelectric and ferromagnetic properties, also at room-temperature, but only for ceramics prepared by Method II. The crucial role of calcination process for avoiding phase separation and obtaining homogeneous structures with ferroelectric and ferromagnetic order is underlined
Advancing integrated research on European river–sea systems: the DANUBIUS-RI project
Research at the interface between terrestrial, riverine, estuarine and marine environments is frequently constrained by significant disciplinary and geographical boundaries. This article outlines an international initiative, DANUBIUS-RI, which aims to address these problems by facilitating biogeochemical monitoring and interdisciplinary research on river–sea systems. The scope of the project spans the environmental, social and economic sciences and was accepted into the European Strategy Forum on Research Infrastructures roadmap in 2016. When operational, DANUBIUS-RI will offer researchers access to interdisciplinary expertise, facilities and European river–sea systems, providing a comprehensive platform for multidisciplinary research and training
Advances in Vehicular Ad-hoc Networks (VANETs): challenges and road-map for future development
Recent advances in wireless communication technologies and auto-mobile industry have triggered a significant research interest in the field of vehicular ad-hoc networks (VANETs) over the past few years. A vehicular network consists of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications supported by wireless access technologies such as IEEE 802.11p. This innovation in wireless communication has been envisaged to improve road safety and motor traffic efficiency in near future through the development of intelligent transportation system (ITS). Hence, governments, auto-mobile industries and academia are heavily partnering through several ongoing research projects to establish standards for VANETs. The typical set of VANET application areas, such as vehicle collision warning and traffic information dissemination have made VANET an interesting field of mobile wireless communication. This paper provides an overview on current research state, challenges, potentials of VANETs as well as the ways forward to achieving the long awaited ITS
Anomalous pre-seismic behavior of the electromagnetic normalized functions related to the intermediate depth earthquakes occurred in Vrancea zone, Romania
In this paper the electromagnetic normalized functions (ENF), carried out in ULF band, have been analyzed in correlation with intermediate depth seismic events occurring in Vrancea zone. To confirm the relationship between anomalous, pre-seismic behavior and an imminent earthquake, a methodology based on the temporal invariability criterion of ENF for a 2-D structure, in non-geodynamic conditions, has been used. The electromagnetic data were collected at the Geodynamic Observatory Provita de Sus (GOPS), placed on the Carpathian electrical conductivity anomaly where the epicentral distance is about 100 km, and the National Geophysical Observatory Surlari (NGOS) taken as a reference and located 140 km from the Vrancea zone. The daily mean distributions of the ENF over a span of several months in 2009, carried out at GOPS, exhibit significant enhancements from the normal trend before all the earthquakes with magnitudes higher than 4. Two correlations between the magnitudes of seismic events and <i>Bzn</i> have to be highlighted: (i) an earthquake of <i>M</i> ≥ 4 is expected to occur when <i>Bzn</i> ≥ 1.846; (ii) meanwhile, the anomalous behaviour of <i>Bzn</i> ≥ 1.851 may be use as pre- seismic value for an earthquake of <i>M</i> ≥ 5. The lead time is closed on 7–15 days before earthquakes occurrence
Transition metal M(II) complexes with isonicotinoylhydrazone-9-anthraldehyde
New complexes of isonicotinoylhydrazone-9-anthraldehyde with Cu(II), Co(II) and Ni(II) have been prepared and characterized by analytical and physico-chemical techniques, such as elemental and thermal analyses, magnetic susceptibility and conductivity measurements, and electronic, EPR and IR spectral studies. The infrared spectral studies revealed the bidentate or monodentate nature of the Schiff base in the complexes; the pyridine nitrogen does not participate in the coordination. A tetrahedral geometry is suggested for the nitrate-complexes and an octahedral geometry for the others. Thermal studies support the chemical formulation of these complexes
Evaluation of alternative options for the irrigation acqueduct of the Cavallino Peninsula using the MULINO approach
- …