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1.
Christos Theoharatos Apostolos Ifantis Nikolaos A. Laskaris George Economou 《Computers & Geosciences》2008,34(6):625-634
An exploratory data analysis (EDA) framework was developed in order to investigate the presence of possible correlations in the long-term geoelectric potential (LTGP) signal, prior to significant seismic events in Western Greece. Experimental data, which had been collected continuously within a 6-year period (1998–2003) at the earthquake signal-acquisition center of the University of Patras Seismological Laboratory (UPSL), were studied. The multidimensional scaling (MDS) technique was used to detect putative clustering tendencies in the ensemble of time-series (TS) segments that could indicate the existence of a possible correlation between the geoelectric signal structure and the impending seismic activity. The end result is a 2-dimensional point diagram with the geometry reflecting important signal characteristics, directly related with the underlying seismic events. In addition, the “appending technique”, a well-suited data analysis methodology was incorporated as a means of relating any other TS segment directly with the pre-computed, via the MDS, point diagram. Using the proposed EDA framework, we examined the presence of similar temporal patterns in the recorded geoelectric TS field, 10 days before the occurrence of the major earthquakes. The presented experimental results indicated clearly the validity of the introduced approach and, further, motivated the use of such advanced visualization schemes for charting precursor trends of significance seismicity. 相似文献
2.
Michael Kenteris Damianos Gavalas Daphne Economou 《Multimedia Tools and Applications》2011,54(2):241-262
This paper introduces an approach of enhancing the tourism experience by incorporating a tool that adopts a “web-to-mobile”
model into tourism websites that allows for the adaptation of personalized tourism web content to be transferred to a mobile
application hosted at users’ mobile device. These applications upon installation to mobile devices allow for browsing of adapted
multimedia content with no requirement for constant network connection. Furthermore so we convey the development experiences
of a multiplatform mobile tourist guide aimed at producing a personalized mobile guide application used in both an online
and offline modes offering services to tourists such as a personal profiling-based recommendation system, a commenting system
and location-based services. This paper focuses on the design, implementation and usability case study of a Multi-Platform
Tourist Guide system for the Municipal Council of Mytilene, Greece. 相似文献
3.
The helium ion microscope has recently emerged as a commercially available instrument. However, its roots go back more than 60 years to the development of the field ion microscope in Berlin, first reported in 1951. Over the intervening years, numerous researchers have pursued the development of a gas field ionization source with the goal of producing a suitable source for an ion microscope. This proved to be an elusive goal until early in this century when a number of discoveries led to a successful source, and shortly thereafter, an instrument fully able to exploit its advantages. Many individuals and many technical advances have come together to make this new class of microscope. The long history of this quest is reviewed along with the recent advances that led to the achievement of this milestone. A brief summary of the current status of the technology and its applications are given. 相似文献
4.
Sotirios Paraschos Prokopios Magiatis Panagiota Gousia Vangelis Economou Hercules Sakkas Chrissanthy Papadopoulou Alexios-Leandros Skaltsounis 《Food chemistry》2011
Mastic water is a commercial flavouring obtained during the steam distillation of mastic resin (the resin of Pistacia lentiscus var. chia) for the production of mastic oil. The mastic water extracts were analysed by GC−MS. The major compounds identified were verbenone, α-terpineol, linalool and trans-pinocarveol. Overall the composition was found to be very different from that of mastic oil. Additional GC−MS revealed the enantiomeric ratio of the chiral constituents of mastic water. The antimicrobial activity of mastic water extract, as well as that of its major constituents, was examined against Escherichia coli, Staphylococcus aureus and Candida spp. including ATCC wild clinical and food-borne strains. Linalool and α-terpineol were found to be the most potent antimicrobial constituents. Finally the stability of mastic water at different temperatures was studied, showing no change in the GC−MS profile of the organic extract for a period of 4 months at storage temperatures up to 4 °C. 相似文献
5.
Segmentation of color images using multiscale clustering and graph theoretic region synthesis 总被引:1,自引:0,他引:1
Makrogiannis S. Economou G. Fotopoulos S. Bourbakis N.G. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2005,35(2):224-238
A multiresolution color image segmentation approach is presented that incorporates the main principles of region-based segmentation and cluster-analysis approaches. The contribution of This work may be divided into two parts. In the first part, a multiscale dissimilarity measure is proposed that makes use of a feature transformation operation to measure the interregion relations with respect to their proximity to the main clusters of the image. As a part of this process, an original approach is also presented to generate a multiscale representation of the image information using nonparametric clustering. In the second part, a graph theoretic algorithm is proposed to synthesize regions and produce the final segmentation results. The latter algorithm emerged from a brief analysis of fuzzy similarity relations in the context of clustering algorithms. This analysis indicates that the segmentation methods in general may be formulated sufficiently and concisely by means of similarity relations theory. The proposed scheme produces satisfying results and its efficiency is indicated by comparing it with: 1) the single scale version of dissimilarity measure and 2) several earlier graph theoretic merging approaches proposed in the literature. Finally, the multiscale processing and region-synthesis properties validate our method for applications, such as object recognition, image retrieval, and emulation of human visual perception. 相似文献
6.
The map displays project was undertaken to investigate techniques for the storage and display of geographical maps and related information and to develop the hardware and software required for a complete working system. Initially most of the project was concerned with the design of graphics hardware to be interfaced to a DEC LSI-11/03 micro-computer which was the main supply of computing power for the project. The development of one of the pieces of specialized hardware, the framestore display, is described. 相似文献
7.
The intention of this experimental work is to investigate the influence of elevated temperatures of short duration (usually during fires in buildings) on the properties of concrete that affect the measurements by non-destructive methods (rebound hammer and pulse velocity). Relationships between strength of concrete as well as rebound and pulse velocity versus heating temperatures are established. Finally, the above results are evaluated to find the direct relation between non-destructive measurements and strength of concrete exposed to fire. 相似文献
8.
Agisilaos Economou 《Renewable & Sustainable Energy Reviews》2010,14(5):1496-1501
Nowadays, the increase of carbon dioxide emissions contributes to the surface temperature's increase and it is the prime cause for the climatic changes. The basic measure that has been taken by world community for the confrontation of this phenomenon was the use of renewable energy sources (RES).This research refers to the use of RES, in the island of Mykonos. It focuses on the repercussions of renewable energy sources on the environment as well as the economic sector. Specifically, it refers to the aeolian parks and to the photovoltaic systems of electric energy production. At the same time, the research takes into account the existing legislative regulations for the uses as well as for the spatial planning frames for the RES.For the exploration of repercussions was used not only the research of elements and that of primary sources but also the methodology of interviews as well as the observation on the spot. The conclusions showed that the correct management of renewable energy sources from regulations of local authorities like the Municipality of Mykonos, as well as the private sector can contribute to the protection of environment and to the economic development of the area. 相似文献
9.
Dafne Molin 《Chemical engineering science》2008,63(9):2402-2407
Spinodal decomposition of a very viscous binary mixture is simulated, assuming that the fluid is bounded by two walls that are instantaneously quenched below the critical temperature. As usual, the mixture phase separates by forming dendritic structures whose size grows with time. While in conventional spinodal decomposition the morphology of the mixture is isotropic, here we show that, when the two components of the mixture have different heat conductivities, the configuration of the mixture may become anisotropic, depending on whether heat propagates slower or faster than mass. Specifically, for large heat conductivity differences, when the Lewis number is small, dendrites tend to align parallel to the isothermal lines; when it is large, dendrites progressively align perpendicular to the isothermal lines. This behavior can be explained observing that the morphology of the mixture is the result of two competing effects: on one hand, the mixture phase separates as soon as its temperature reaches its critical value and therefore it tends to follow the isothermal lines; on the other hand, the system tend to maximize heat transport, and therefore dendrites tend to span between the two quenched walls, i.e. perpendicular to the isothermal lines. This explanation is confirmed showing that when the imposed temperature difference between the side walls (and therefore the heat flux at equilibrium as well) is increased, dendrites tend to align across the walls more and more. 相似文献
10.
MP Golombek RA Cook T Economou WM Folkner AF Haldemann PH Kallemeyn JM Knudsen RM Manning HJ Moore TJ Parker R Rieder JT Schofield PH Smith RM Vaughan 《Canadian Metallurgical Quarterly》1997,278(5344):1743-1748
Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free. 相似文献