Advanced DriverAssistance Systems(ADAS)technologies can assist drivers or be part of automatic driving systems to support the driving process and improve the level of safety and comfort on the road.Traffic Sign Recogn...Advanced DriverAssistance Systems(ADAS)technologies can assist drivers or be part of automatic driving systems to support the driving process and improve the level of safety and comfort on the road.Traffic Sign Recognition System(TSRS)is one of themost important components ofADAS.Among the challengeswith TSRS is being able to recognize road signs with the highest accuracy and the shortest processing time.Accordingly,this paper introduces a new real time methodology recognizing Speed Limit Signs based on a trio of developed modules.Firstly,the Speed Limit Detection(SLD)module uses the Haar Cascade technique to generate a new SL detector in order to localize SL signs within captured frames.Secondly,the Speed Limit Classification(SLC)module,featuring machine learning classifiers alongside a newly developed model called DeepSL,harnesses the power of a CNN architecture to extract intricate features from speed limit sign images,ensuring efficient and precise recognition.In addition,a new Speed Limit Classifiers Fusion(SLCF)module has been developed by combining trained ML classifiers and the DeepSL model by using the Dempster-Shafer theory of belief functions and ensemble learning’s voting technique.Through rigorous software and hardware validation processes,the proposedmethodology has achieved highly significant F1 scores of 99.98%and 99.96%for DS theory and the votingmethod,respectively.Furthermore,a prototype encompassing all components demonstrates outstanding reliability and efficacy,with processing times of 150 ms for the Raspberry Pi board and 81.5 ms for the Nano Jetson board,marking a significant advancement in TSRS technology.展开更多
Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. ...Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. The 7050 alloy machining chips were spray formed, hot extruded, rotary swaged and heat-treated in order to improve mechanical properties. Microstructures, tensile properties and fatigue strength results for a 2.7 mm-diameter recycled wire are presented. Secondary phases and precipitates were investigated by XRD, SEM, EBSD, TEM and DSC. As-swaged and heat-treated(solution and aging) conditions were evaluated. Mechanical properties of both conditions outperformed AA7050 aerospace specification. Substantial grain refinement resulted from the extensive plastic deformation imposed by rotary swaging. Refined micrometric and sub-micrometric Al grains, as well as coarse and fine intermetallic precipitates were observed. Subsequent solution treatment resulted in a homogeneous, recrystallized and equiaxed microstructure with grain size of 9 μm. Nanoscale GP(I) zones and η′ phase precipitates formed after aging at 120 ℃, imparting higher tensile(586 MPa) and fatigue(198 MPa) strengths.展开更多
Bulk materials were synthesized by the Bridgman technique using the elements Cu, Ga, Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X...Bulk materials were synthesized by the Bridgman technique using the elements Cu, Ga, Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity. Optical response (Photoconductivity) and Photoluminescence (PL) and PL-excitation (PLE) at temperatures from 4.2 to 77 K were also used to estimate the band-gap energy of Cu-Ga<sub>3</sub>Se<sub>5</sub>. They show a nearly perfect stoechiometry and present p-type conductivity. CuGa<sub>3</sub>Se<sub>5</sub> either have an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained by Photoconductivity and Photoluminescence (PL) for the different samples is 1.85 eV. Studying the variation of the gap as a function of the temperature shows that the transition is a D-A type. The defects that appear are probably Ga<sub>Cu</sub>.展开更多
This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The p...This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The problem of the estimation of stability for this type of process is set. The central objective is to obtain a bounded stability index expressed in terms of the Lévy-Prokhorov metric;likewise, sufficient conditions are provided for the existence of such inequalities.展开更多
Since 3D mesh security has become intellectual property,3D watermarking algorithms have continued to appear to secure 3D meshes shared by remote users and saved in distant multimedia databases.The novelty of our appro...Since 3D mesh security has become intellectual property,3D watermarking algorithms have continued to appear to secure 3D meshes shared by remote users and saved in distant multimedia databases.The novelty of our approach is that it uses a new Clifford-multiwavelet transform to insert copyright data in a multiresolution domain,allowing us to greatly expand the size of the watermark.After that,our method does two rounds of insertion,each applying a different type of Clifford-wavelet transform.Before being placed into the Clifford-multiwavelet coefficients,the watermark,which is a mixture of the mesh description,source mesh signature(produced using SHA512),and a logo encrypted using the RSA(Ronald Shamir Adleman)technique,is encoded using Turbo-code.Using the Least Significant Bit method steps,data embedding involves modulation and insertion processes.Finally,the watermarked mesh is reconstructed using the inverse Cliffordmultiwavelet transform.Due to the utilization of a hybrid insertion domain,our technique has demonstrated a very high insertion rate while retaining mesh quality.The mesh is watermarked,and the extracted data is acquired in real-time.Our approach is also resistant to the most common types of attacks.Our findings reveal that the current approach improves on previous efforts.展开更多
Bulk materials were synthesized by the Bridgman technique using the elements Cu, In and Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as b...Bulk materials were synthesized by the Bridgman technique using the elements Cu, In and Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity, Optical response (Photoconductivity) and Photoluminescence (PL) to determine the band gap value and Spectroscopic Ellipsometry to find energy levels above the gap in the band scheme at room-temperature. They show a nearly perfect stoechiometry and present a p-type conductivity. CuIn3Se5 either has a Stannite structure, an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained for the different samples was 1.23 eV. Energy levels above the gap in the band scheme were determinate by measuring the dielectric function at room temperature for energies lying between 1.5 and 5.5 eV. Many transitions were observed above the gap for different samples. Spectroscopic Ellipsometry gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum.展开更多
Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing ...Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing environments have been suggested:(i)via plasticity in morphological or physiological traits,invasive plants are able to maintain a higher fitness than native plants in a range of environ-ments,including stressful or low-resource habitats:a‘Jack-of-all-trades’strategy;(ii)phenotypic plasticity allows the invader to better exploit resources available in low stress or favorable habitats,show-ing higher fitness than native ones:a‘Master-of-some’strategy and(iii)a combination of these abilities,the‘Jack-and-Master’strategy.Methods We evaluated these strategies in the successful invader Taraxacum officinale in a controlled experiment mimicking natural environmen-tal gradients.We set up three environmental gradients consisting of factorial arrays of two levels of temperature/light,temperature/water and light/water,respectively.We compared several ecophysiologi-cal traits,as well as the reaction norm in fitness-related traits,in both T.officinale and the closely related native Hypochaeris thrin-cioides subjected to these environmental scenarios.Important Findings Overall,T.officinale showed significantly greater accumulation of biomass and higher survival than the native H.thrincioides,with this difference being more pronounced toward both ends of each gradient.T.officinale also showed significantly higher plasticity than its native counterpart in several ecophysiological traits.Therefore,T.officinale exhibits a Jack-and-Master strategy as it is able to main-tain higher biomass and survival in unfavorable conditions,as well as to increase fitness when conditions are favorable.We suggest that this strategy is partly based on ecophysiological responses to the environment,and that it may contribute to explaining the successful invasion of T.officinale across different habitats.展开更多
文摘Advanced DriverAssistance Systems(ADAS)technologies can assist drivers or be part of automatic driving systems to support the driving process and improve the level of safety and comfort on the road.Traffic Sign Recognition System(TSRS)is one of themost important components ofADAS.Among the challengeswith TSRS is being able to recognize road signs with the highest accuracy and the shortest processing time.Accordingly,this paper introduces a new real time methodology recognizing Speed Limit Signs based on a trio of developed modules.Firstly,the Speed Limit Detection(SLD)module uses the Haar Cascade technique to generate a new SL detector in order to localize SL signs within captured frames.Secondly,the Speed Limit Classification(SLC)module,featuring machine learning classifiers alongside a newly developed model called DeepSL,harnesses the power of a CNN architecture to extract intricate features from speed limit sign images,ensuring efficient and precise recognition.In addition,a new Speed Limit Classifiers Fusion(SLCF)module has been developed by combining trained ML classifiers and the DeepSL model by using the Dempster-Shafer theory of belief functions and ensemble learning’s voting technique.Through rigorous software and hardware validation processes,the proposedmethodology has achieved highly significant F1 scores of 99.98%and 99.96%for DS theory and the votingmethod,respectively.Furthermore,a prototype encompassing all components demonstrates outstanding reliability and efficacy,with processing times of 150 ms for the Raspberry Pi board and 81.5 ms for the Nano Jetson board,marking a significant advancement in TSRS technology.
基金supported by CAPES, FINEP (FINEP/CTENERG: 01.09.0485.00)a FAPESP Project (2013/05987-8)a BPE grant awarded to C.R.M. Afonso (2015/19978-6)
文摘Recycled high-strength aluminum alloys have limited use as structural materials due to poor mechanical properties. Spray forming remelting followed by hot extrusion is a promising route for reprocessing 7 xxx alloys. The 7050 alloy machining chips were spray formed, hot extruded, rotary swaged and heat-treated in order to improve mechanical properties. Microstructures, tensile properties and fatigue strength results for a 2.7 mm-diameter recycled wire are presented. Secondary phases and precipitates were investigated by XRD, SEM, EBSD, TEM and DSC. As-swaged and heat-treated(solution and aging) conditions were evaluated. Mechanical properties of both conditions outperformed AA7050 aerospace specification. Substantial grain refinement resulted from the extensive plastic deformation imposed by rotary swaging. Refined micrometric and sub-micrometric Al grains, as well as coarse and fine intermetallic precipitates were observed. Subsequent solution treatment resulted in a homogeneous, recrystallized and equiaxed microstructure with grain size of 9 μm. Nanoscale GP(I) zones and η′ phase precipitates formed after aging at 120 ℃, imparting higher tensile(586 MPa) and fatigue(198 MPa) strengths.
文摘Bulk materials were synthesized by the Bridgman technique using the elements Cu, Ga, Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity. Optical response (Photoconductivity) and Photoluminescence (PL) and PL-excitation (PLE) at temperatures from 4.2 to 77 K were also used to estimate the band-gap energy of Cu-Ga<sub>3</sub>Se<sub>5</sub>. They show a nearly perfect stoechiometry and present p-type conductivity. CuGa<sub>3</sub>Se<sub>5</sub> either have an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained by Photoconductivity and Photoluminescence (PL) for the different samples is 1.85 eV. Studying the variation of the gap as a function of the temperature shows that the transition is a D-A type. The defects that appear are probably Ga<sub>Cu</sub>.
文摘This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The problem of the estimation of stability for this type of process is set. The central objective is to obtain a bounded stability index expressed in terms of the Lévy-Prokhorov metric;likewise, sufficient conditions are provided for the existence of such inequalities.
基金This research work was funded by the Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia through the project number(IF-PSAU-2021/01/17567)。
文摘Since 3D mesh security has become intellectual property,3D watermarking algorithms have continued to appear to secure 3D meshes shared by remote users and saved in distant multimedia databases.The novelty of our approach is that it uses a new Clifford-multiwavelet transform to insert copyright data in a multiresolution domain,allowing us to greatly expand the size of the watermark.After that,our method does two rounds of insertion,each applying a different type of Clifford-wavelet transform.Before being placed into the Clifford-multiwavelet coefficients,the watermark,which is a mixture of the mesh description,source mesh signature(produced using SHA512),and a logo encrypted using the RSA(Ronald Shamir Adleman)technique,is encoded using Turbo-code.Using the Least Significant Bit method steps,data embedding involves modulation and insertion processes.Finally,the watermarked mesh is reconstructed using the inverse Cliffordmultiwavelet transform.Due to the utilization of a hybrid insertion domain,our technique has demonstrated a very high insertion rate while retaining mesh quality.The mesh is watermarked,and the extracted data is acquired in real-time.Our approach is also resistant to the most common types of attacks.Our findings reveal that the current approach improves on previous efforts.
文摘Bulk materials were synthesized by the Bridgman technique using the elements Cu, In and Se. These samples were characterized by Energy Dispersive Spectrometry (EDS) to determine the elemental composition, as well as by X-ray diffraction for structure, hot point probe method for type of conductivity, Optical response (Photoconductivity) and Photoluminescence (PL) to determine the band gap value and Spectroscopic Ellipsometry to find energy levels above the gap in the band scheme at room-temperature. They show a nearly perfect stoechiometry and present a p-type conductivity. CuIn3Se5 either has a Stannite structure, an Ordered Defect Chalcopyrite structure (ODC), or an Ordered Vacancy Chalcopyrite structure (OVC). The gap energy obtained for the different samples was 1.23 eV. Energy levels above the gap in the band scheme were determinate by measuring the dielectric function at room temperature for energies lying between 1.5 and 5.5 eV. Many transitions were observed above the gap for different samples. Spectroscopic Ellipsometry gave evidence for the interpretation of the choice of gap values which were compatible with that obtained from solar spectrum.
文摘Aims Successful invasive plants are often assumed to display significant levels of phenotypic plasticity.Three possible strategies by which phenotypic plasticity may allow invasive plant species to thrive in changing environments have been suggested:(i)via plasticity in morphological or physiological traits,invasive plants are able to maintain a higher fitness than native plants in a range of environ-ments,including stressful or low-resource habitats:a‘Jack-of-all-trades’strategy;(ii)phenotypic plasticity allows the invader to better exploit resources available in low stress or favorable habitats,show-ing higher fitness than native ones:a‘Master-of-some’strategy and(iii)a combination of these abilities,the‘Jack-and-Master’strategy.Methods We evaluated these strategies in the successful invader Taraxacum officinale in a controlled experiment mimicking natural environmen-tal gradients.We set up three environmental gradients consisting of factorial arrays of two levels of temperature/light,temperature/water and light/water,respectively.We compared several ecophysiologi-cal traits,as well as the reaction norm in fitness-related traits,in both T.officinale and the closely related native Hypochaeris thrin-cioides subjected to these environmental scenarios.Important Findings Overall,T.officinale showed significantly greater accumulation of biomass and higher survival than the native H.thrincioides,with this difference being more pronounced toward both ends of each gradient.T.officinale also showed significantly higher plasticity than its native counterpart in several ecophysiological traits.Therefore,T.officinale exhibits a Jack-and-Master strategy as it is able to main-tain higher biomass and survival in unfavorable conditions,as well as to increase fitness when conditions are favorable.We suggest that this strategy is partly based on ecophysiological responses to the environment,and that it may contribute to explaining the successful invasion of T.officinale across different habitats.
