We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Hel...We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Helmholtz equations. We prove the classical reciprocity principle, a general scattering theorem and an optical theorem in R<sup>2</sup>. Using Herglotz wave functions we define the corresponding far field operator. Applying the general scattering theorem useful relations are proved for the reconstruction of the scatterer. We also prove that for real chirality measure of the penetrable scatterer the far field operator has a countable number of eigenvalues which lie on a circle.展开更多
A comprehensive study of an all-optical chaotic communication system,including experimental realization,real-world testing and performance characterization through bit-error-rate analysis,is presented.Pseudorandom bit...A comprehensive study of an all-optical chaotic communication system,including experimental realization,real-world testing and performance characterization through bit-error-rate analysis,is presented.Pseudorandom bit sequences that are effectively encrypted in a broadband carrier produced by a chaotic emitter and sent for transmission are recovered at the receiver side.Bit-error-rate(BER) values as low as 10-7 for 1 Gb/s data rate have been achieved.Different data code lengths and bit-rates at the Gb/s region have been tested.The application of optical transmission using 100km fiber spools in an in-situ experiment and 120km in an installed optical network showed that transmission effects do not act as a considerably deteriorating factor in the final performance of chaos-based optical communication systems.展开更多
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi...In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.展开更多
A time-harmonic plane acoustic wave is scattered by a piecewise homogeneous obstacle with a penetrable or impenetrable core. We construct in the close form an integral representation for the far field pattern in which...A time-harmonic plane acoustic wave is scattered by a piecewise homogeneous obstacle with a penetrable or impenetrable core. We construct in the close form an integral representation for the far field pattern in which we have incorporated the physical and geometrical characteristics of the scatterer. Through this representation, we obtain the far field pattern for this scatterer. We prove scattering relations between the far field patterns of two scattering problems due to two distinct incident waves on the same scatterer. In particular, we prove reciprocity and general scattering theorems. The optical theorem, connecting the total power that the scatterer extracts from the incident plane wave either by radiation or by absorption with the corresponding far field pattern of an incident plane wave, is recovered as a corollary of the general scattering theorem. Moreover, if we consider incident waves to be both a plane and a spherical, we derive a mixed reciprocity theorem. We define the corresponding far field operators and using these relations, we prove some properties that can be used for solving inverse scattering problems.展开更多
The Agriculture business domain,as a vital part of the overall supply chain,is expected to highly evolve in the upcoming years via the developments,which are taking place on the side of the Future Internet.This paper ...The Agriculture business domain,as a vital part of the overall supply chain,is expected to highly evolve in the upcoming years via the developments,which are taking place on the side of the Future Internet.This paper presents a novel Business-to-Business collaboration platform from the agri-food sector perspective,which aims to facilitate the collaboration of numerous stakeholders belonging to associated business domains,in an effective and flexible manner.The contemporary B2B collaboration schemes already place the requirements for swift deployment of cloud applications,capable of both integrating diverse legacy systems,as well as developing in a rapid way new services and systems,which will be able to instantly communicate and provide complete,"farm-to-fork"solutions for farmers,agrifood and logistics service providers,ICT companies,end-product producers,etc.To this end,this conceptual paper describes how these requirements are addressed via the FIspace B2B platform,focusing on the Greenhouse Management&Control scenarios.展开更多
With the rapid development of photogrammetry,computer vision and three-dimensional(3D)modeling technologies,it is possible to efficiently construct detailed 3D urban models.Accordingly,large corpora of 3D models,such ...With the rapid development of photogrammetry,computer vision and three-dimensional(3D)modeling technologies,it is possible to efficiently construct detailed 3D urban models.Accordingly,large corpora of 3D models,such as the Google 3D Warehouse,are now becoming freely available on the web.How to find the proper 3D urban models is a challenging research issue.In this paper,we join shape descriptors and color descriptors for 3D urban model retrieval.The query objects are localized and segmented automatically from the input images by using a new selective search voting algorithm.Through combining the normalization with the light field descriptor,the Horizontal Light Descriptor is introduced to measure the shape similarity among the normalized urban models.The color descriptors are used to represent the color information of the urban models.The two types of descriptors are joined to search 3D urban models similar to the query objects.Experimental results have shown the effectiveness of our approach.展开更多
The Network Makeup Artist(NORMA) is a web tool for interactive network annotation visualization and topological analysis, able to handle multiple networks and annotations simultaneously. Precalculated annotations(e.g....The Network Makeup Artist(NORMA) is a web tool for interactive network annotation visualization and topological analysis, able to handle multiple networks and annotations simultaneously. Precalculated annotations(e.g., Gene Ontology, Pathway enrichment, community detection,or clustering results) can be uploaded and visualized in a network, either as colored pie-chart nodes or as color-filled areas in a 2D/3D Venn-diagram-like style. In the case where no annotation exists,algorithms for automated community detection are offered. Users can adjust the network views using standard layout algorithms or allow NORMA to slightly modify them for visually better group separation. Once a network view is set, users can interactively select and highlight any group of interest in order to generate publication-ready figures. Briefy, with NORMA, users can encode three types of information simultaneously. These are 1) the network, 2) the communities or annotations of interest, and 3) node categories or expression values. Finally, NORMA offers basic topological analysis and direct topological comparison across any of the selected networks. NORMA service is available at http://norma.pavlopouloslab.info, whereas the code is available at https://github.com/Pavlopoulos Lab/NORMA.展开更多
文摘We consider the scattering of time-harmonic plane waves by an infinitely long penetrable chiral cylinder. The electromagnetic scattering problem is reduced to a transmission problem for a system of two-dimensional Helmholtz equations. We prove the classical reciprocity principle, a general scattering theorem and an optical theorem in R<sup>2</sup>. Using Herglotz wave functions we define the corresponding far field operator. Applying the general scattering theorem useful relations are proved for the reconstruction of the scatterer. We also prove that for real chirality measure of the penetrable scatterer the far field operator has a countable number of eigenvalues which lie on a circle.
文摘A comprehensive study of an all-optical chaotic communication system,including experimental realization,real-world testing and performance characterization through bit-error-rate analysis,is presented.Pseudorandom bit sequences that are effectively encrypted in a broadband carrier produced by a chaotic emitter and sent for transmission are recovered at the receiver side.Bit-error-rate(BER) values as low as 10-7 for 1 Gb/s data rate have been achieved.Different data code lengths and bit-rates at the Gb/s region have been tested.The application of optical transmission using 100km fiber spools in an in-situ experiment and 120km in an installed optical network showed that transmission effects do not act as a considerably deteriorating factor in the final performance of chaos-based optical communication systems.
基金Support to the SatNEx-Ⅲ Network of Experts (SatNEx-Ⅲ) CoO2,2011-2012
文摘In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates.
文摘A time-harmonic plane acoustic wave is scattered by a piecewise homogeneous obstacle with a penetrable or impenetrable core. We construct in the close form an integral representation for the far field pattern in which we have incorporated the physical and geometrical characteristics of the scatterer. Through this representation, we obtain the far field pattern for this scatterer. We prove scattering relations between the far field patterns of two scattering problems due to two distinct incident waves on the same scatterer. In particular, we prove reciprocity and general scattering theorems. The optical theorem, connecting the total power that the scatterer extracts from the incident plane wave either by radiation or by absorption with the corresponding far field pattern of an incident plane wave, is recovered as a corollary of the general scattering theorem. Moreover, if we consider incident waves to be both a plane and a spherical, we derive a mixed reciprocity theorem. We define the corresponding far field operators and using these relations, we prove some properties that can be used for solving inverse scattering problems.
基金The research,leading to these results,has received funding from the European Commission’s Seventh Framework program FP7-ICT-2012 under grant agreement N°604123 also referred to as FIspace(Future Internet Business Collaboration Networks in Agri-Food,Transport and Logistics).
文摘The Agriculture business domain,as a vital part of the overall supply chain,is expected to highly evolve in the upcoming years via the developments,which are taking place on the side of the Future Internet.This paper presents a novel Business-to-Business collaboration platform from the agri-food sector perspective,which aims to facilitate the collaboration of numerous stakeholders belonging to associated business domains,in an effective and flexible manner.The contemporary B2B collaboration schemes already place the requirements for swift deployment of cloud applications,capable of both integrating diverse legacy systems,as well as developing in a rapid way new services and systems,which will be able to instantly communicate and provide complete,"farm-to-fork"solutions for farmers,agrifood and logistics service providers,ICT companies,end-product producers,etc.To this end,this conceptual paper describes how these requirements are addressed via the FIspace B2B platform,focusing on the Greenhouse Management&Control scenarios.
基金supported by the National Natural Science Foundation of China[Grant 41371324].
文摘With the rapid development of photogrammetry,computer vision and three-dimensional(3D)modeling technologies,it is possible to efficiently construct detailed 3D urban models.Accordingly,large corpora of 3D models,such as the Google 3D Warehouse,are now becoming freely available on the web.How to find the proper 3D urban models is a challenging research issue.In this paper,we join shape descriptors and color descriptors for 3D urban model retrieval.The query objects are localized and segmented automatically from the input images by using a new selective search voting algorithm.Through combining the normalization with the light field descriptor,the Horizontal Light Descriptor is introduced to measure the shape similarity among the normalized urban models.The color descriptors are used to represent the color information of the urban models.The two types of descriptors are joined to search 3D urban models similar to the query objects.Experimental results have shown the effectiveness of our approach.
基金supported by the Operational Program Competitiveness,Entrepreneurship,Innovation,NSRF 2014-2020 (Grant No.MIS 5002562,co-financed by Greece and the European Union (European Regional Development Fund)supported by the Hellenic Foundation for Research and Innovation (HFRI) under the"First Call for HFRI Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant"(Grant No.1855-BOLOGNA)+2 种基金supported by the Action Strengthening Human ResourcesEducation and Lifelong Learning,2014-2020,co-funded by the European Social Fund (ESF) and the Greek State (Grant No.MIS 5000432)supported by a grant from the Stavros Niarchos Foundation to the Biomedical Sciences Research Center"Alexander Fleming",as part of the initiative of the Foundation to support the Greek research center ecosystem
文摘The Network Makeup Artist(NORMA) is a web tool for interactive network annotation visualization and topological analysis, able to handle multiple networks and annotations simultaneously. Precalculated annotations(e.g., Gene Ontology, Pathway enrichment, community detection,or clustering results) can be uploaded and visualized in a network, either as colored pie-chart nodes or as color-filled areas in a 2D/3D Venn-diagram-like style. In the case where no annotation exists,algorithms for automated community detection are offered. Users can adjust the network views using standard layout algorithms or allow NORMA to slightly modify them for visually better group separation. Once a network view is set, users can interactively select and highlight any group of interest in order to generate publication-ready figures. Briefy, with NORMA, users can encode three types of information simultaneously. These are 1) the network, 2) the communities or annotations of interest, and 3) node categories or expression values. Finally, NORMA offers basic topological analysis and direct topological comparison across any of the selected networks. NORMA service is available at http://norma.pavlopouloslab.info, whereas the code is available at https://github.com/Pavlopoulos Lab/NORMA.
