AIM: To identify demographic and clinical factors asso-ciated with disabling Crohn's disease (CD). METHODS: A systematic review and meta-analysisof observational studies, focusing on the factors that can predict t...AIM: To identify demographic and clinical factors asso-ciated with disabling Crohn's disease (CD). METHODS: A systematic review and meta-analysisof observational studies, focusing on the factors that can predict the prognosis of different outcomes of CD was undertaken. PubMed, ISI Web of Knowledge and Scopus were searched to identify studies investigat-ing the above mentioned factors in adult patients with CD. Studies were eligible for inclusion if they describe prognostic factors in CD, with inclusion and exclusion criteria defined as follows. Studies with adult patients and CD, written in English and studying association between clinical factors and at least one prognosis out-come were included. Meta-analysis of effects was un-dertaken for the disabling disease outcome, using odds ratio (OR) to assess the effect of the different factors in the outcome. The statistical method used was Mantel-Haenszel for fixed effects. The 16-item quality assess-ment tool (QATSDD) was used to assess the quality of the studies (range: 0-42). RESULTS: Of the 913 papers initially selected, sixty studies were reviewed and three were included in the systematic review and meta-analysis. The global QA-TSDD scores of papers were 18, 21 and 22. Of a total of 1961 patients enrolled, 1332 (78%) were classified with disabling disease five years after diagnosis. In two studies, age at diagnosis was a factor associated with disabling disease five years after diagnosis. Individu-als under 40 years old had a higher risk of developing disabling disease. In two studies, patients who were treated with corticosteroids on the first flare developed disabling disease five years after diagnosis. Further, perianal disease was found to be relevant in all of the studies at two and five years after diagnosis. Finally, one study showed localization as a factor associated with disabling disease five years after diagnosis, with L3 being a higher risk factor. This meta-analysis showed a significantly higher risk of developing disabling dis-ease at five years after initial diagnosis among patients younger than 40 years of age (OR=2.47, 95%CI: 1.74-3.51), with initial steroid treatment for first flare (OR=2.42, 95%CI: 1.87-3.11) and with perianal dis-ease (OR = 2.00, 95%CI: 1.41-2.85).CONCLUSION: Age at diagnosis, perianal disease, ini-tial use of steroids and localization seem to be indepen-dent prognostic factors of disabling disease.展开更多
In the conventional robust optimization(RO)context,the uncertainty is regarded as residing in a predetermined and fixed uncertainty set.In many applications,however,uncertainties are affected by decisions,making the c...In the conventional robust optimization(RO)context,the uncertainty is regarded as residing in a predetermined and fixed uncertainty set.In many applications,however,uncertainties are affected by decisions,making the current RO framework inapplicable.This paper investigates a class of two-stage RO problems that involve decision-dependent uncertainties.We introduce a class of polyhedral uncertainty sets whose right-hand-side vector has a dependency on the here-and-now decisions and seek to derive the exact optimal wait-and-see decisions for the second-stage problem.A novel iterative algorithm based on the Benders dual decomposition is proposed where advanced optimality cuts and feasibility cuts are designed to incorporate the uncertainty-decision coupling.The computational tractability,robust feasibility and optimality,and convergence performance of the proposed algorithm are guaranteed with theoretical proof.Four motivating application examples that feature the decision-dependent uncertainties are provided.Finally,the proposed solution methodology is verified by conducting case studies on the pre-disaster highway investment problem.展开更多
Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clini...Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures.This technique turns biological tissues more transparent through two main mechanisms-tissue dehydration and refractive index(RI)matching between tissue compo-nents.Such matching is obtained by partial replacement of interstit ial water by a biocompat ible agent that presents higher RI and it can be completely rever sible by natural rehydration in vrivo or by assisted rehydration in ex vivo tissues.Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary.Using a simple method,based on collimated transmittance and thickness measurements made from muscle samples under treatment,we have estimated the diffusion properties of glucose,ethylene glycol(EG)and water that were used to perform such char acterization and discrimination.Comparing these properties with data from literature that characterize their diffusion in water we have observed that musde cell membrane permeability limits agent and water diffusion in the muscle.The same experi-mental data has allowed to calculate the optical dearing(OC)eficiency and make an inter-pretation of the internal changes that occurred in muscle during the treatments.The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a consider.able improvement of optical tomogr aphic techmiques with better contrast and in depth imaging.展开更多
In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a di...In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.展开更多
Staff scheduling and rostering problems, with application in several application areas, from transportation systems to hospitals, have been widely addressed by researchers. This is not the case of hospitality services...Staff scheduling and rostering problems, with application in several application areas, from transportation systems to hospitals, have been widely addressed by researchers. This is not the case of hospitality services, which have been forgotten by the quantitative research literature. The purpose of this paper is to provide some insights on the application of staff scheduling and rostering problems to hospitality management operations, reviewing existing approaches developed in other similar areas, such as nurse rostering or examining adaptable problem models, such as the tour scheduling.展开更多
With the objective to study the variation of optical properties of rat muscle during optical clearing,we have performed a set of optical measurements from that kind of tissue.The.measurements performed were total tr a...With the objective to study the variation of optical properties of rat muscle during optical clearing,we have performed a set of optical measurements from that kind of tissue.The.measurements performed were total tr ansmittance,ollimated transmit tance,specular reflec-tance and total reflectance.This set of measurements is suficient to determine diffuse reflectance and absorbance of the sample,also necessary to est imate the optical properties.All the per formed measurements and calculated quantities will be used later in inverse Monte Carlo(IMC)simu-lations to determine the evolution of the optical properties of muscle during treatments with ethylene glycol and glucose.The results obt ained with the measurements already provide some information about the optical c learing treatments applied to the muscle and translate the mechanisms of turning the tissue more transparent and sequence of regimes of optical clearing.展开更多
Purpose:Current Direct Observation(DO)methods are burdensome to the observer and relevant limitations can be identified on the outcome information.This study aims to characterize DO from the observers’point of view a...Purpose:Current Direct Observation(DO)methods are burdensome to the observer and relevant limitations can be identified on the outcome information.This study aims to characterize DO from the observers’point of view and to analyze the feasibility and usefulness of visual information in the form of video.Method:data collection was done with ten adult males,observed while performing different physical activities in an indoor court.Sessions were video recorded by two cameras.Three observers performed systematic observation,using SOPLAY,with different sampling rates.Inter observer’s agreement and with reference data was analyzed by Cohen’s Kappa statistic.Results:SOPLAY highest agreement between observers was 0.611 on vigorous category and walking category had the lowest 0.188.It doubles the time needed to annotate the video with pauses,but half of player’s behavior is preserved.Conclusion(s):using video to support DO permits to collect more accurate data and a more detailed behavior categorization is warranted.Developments in computer vision are expected to reduce the human efforts in DO methods.展开更多
Wind energy is considered a hope in future as a clean and sustainable energy, as can be seen by the growing number of wind farms installed all over the world. With the huge proliferation of wind farms, as an alternati...Wind energy is considered a hope in future as a clean and sustainable energy, as can be seen by the growing number of wind farms installed all over the world. With the huge proliferation of wind farms, as an alternative to the traditional fossil power generation, the economic issues dictate the necessity of monitoring systems to optimize the availability and profits. The relatively high cost of operation and maintenance associated to wind power is a major issue. Wind turbines are most of the time located in remote areas or offshore and these factors increase the referred operation and maintenance costs. Good maintenance strategies are needed to increase the health management of wind turbines. The objective of this paper is to show the application of neural networks to analyze all the wind turbine information to identify possible future failures, based on previous information of the turbine.展开更多
This paper captures an engaging—and at times heated—Power-Globe(PG)discussion of evolving definitions of smart grid technologies.The exchange took place between December 2024 and January 2025.The primary objective o...This paper captures an engaging—and at times heated—Power-Globe(PG)discussion of evolving definitions of smart grid technologies.The exchange took place between December 2024 and January 2025.The primary objective of this paper is to clarify some of the ambiguities surrounding the term“smart grid”over the past two decades,as highlighted in the spirited PG debate.“Smart grid”has sometimes been advocated as a panacea to resolve the tension between competing objectives for the provision of electricity(specifically,making it reliable,clean,and affordable).This paper examines the term“smart grid”in terms of raw technical functionalities,applications,and use cases,some of which may get closer than others to meeting the aspirational promises.While smart technology should expand our menu of options,it will not absolve us of the need to make hard decisions.展开更多
The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, in...The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored Bragg grating structures fabricated by this method are shown. Apodized Bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled Bragg gratings with equalized peaks equally spaced by 0.8 nm （100 GHz） were also fabricated.展开更多
COSMO-SkyMed is a constellation of four X-band high-resolution radar satellites with a minimum revisit period of 12 hours.These satellites can obtain ascending and descending synthetic aperture radar(SAR)images with v...COSMO-SkyMed is a constellation of four X-band high-resolution radar satellites with a minimum revisit period of 12 hours.These satellites can obtain ascending and descending synthetic aperture radar(SAR)images with very similar periods for use in the three-dimensional(3D)inversion of glacier velocities.In this paper,based on ascending and descending COSMO-SkyMed data acquired at nearly the same time,the surface velocity of the Yiga Glacier,located in the Jiali County,Tibet,China,is estimated in four directions using an offset tracking technique during the periods of 16 January to 3 February 2017 and 1 February to 19 February 2017.Through the geometrical relationships between the measurements and the SAR images,the least square method is used to retrieve the 3D components of the glacier surface velocity in the eastward,northward and upward directions.The results show that applying the offset tracking technique to COSMO-SkyMed images can be used to derive the true 3D velocity of a glacier’s surface.During the two periods,the Yiga Glacier had a stable velocity,and the maximum surface velocity,2.4 m/d,was observed in the middle portion of the glacier,which corresponds to the location of the steepest slope.展开更多
The growing integration of renewable energy sources and the widespread electrification of the energy demand have significantly reduced the capacity margin of the electrical grid.This demands a more flexible approach t...The growing integration of renewable energy sources and the widespread electrification of the energy demand have significantly reduced the capacity margin of the electrical grid.This demands a more flexible approach to grid operation,for instance,combining real-time topology optimization and redispatching.Traditional expertdriven decision-making rules may become insufficient to manage the increasing complexity of real-time grid operations and derive remedial actions under the N-1 contingency.This work proposes a novel hybrid AI framework for power grid topology control that integrates genetic network programming(GNP),reinforcement learning,and decision trees.A new variant of GNP is introduced that is capable of evolving the decision-making rules by learning from data in a reinforcement learning framework.The graph-based evolutionary structure of GNP and decision trees enables transparent,traceable reasoning.The proposed method outperforms both a baseline expert system and a state-of-the-art deep reinforcement learning agent on the IEEE 118-bus system,achieving up to an 28%improvement in a key performance metric used in the Learning to Run a Power Network(L2RPN)competition.展开更多
In a high-risk sector,such as power system,trans parency and interpretability are key principles for effectively deploying artificial intelligence(AI)in control rooms.There fore,this paper proposes a novel methodology...In a high-risk sector,such as power system,trans parency and interpretability are key principles for effectively deploying artificial intelligence(AI)in control rooms.There fore,this paper proposes a novel methodology,the evolving sym bolic model(ESM),which is dedicated to generating highly in terpretable data-driven models for dynamic security assessment(DSA),namely in system security classification(SC)and the def inition of preventive control actions.The ESM uses simulated annealing for a data-driven evolution of a symbolic model tem plate,enabling different cooperative learning schemes between humans and AI.The Madeira Island power system is used to validate the application of the ESM for DSA.The results show that the ESM has a classification accuracy comparable to pruned decision trees(DTs)while boasting higher global inter pretability.Moreover,the ESM outperforms an operator-de fined expert system and an artificial neural network in defining preventive control actions.展开更多
The rapidly increasing penetration of electric vehicles(EVs) in modern metropolises has been witnessed during the past decade, inspired by financial subsidies as well as public awareness of climate change and environm...The rapidly increasing penetration of electric vehicles(EVs) in modern metropolises has been witnessed during the past decade, inspired by financial subsidies as well as public awareness of climate change and environment pro-tection. Integrating charging facilities, especially highpower chargers in fast charging stations, into power distribution systems remarkably alters the traditional load flow pattern, and thus imposes great challenges on the operation of distribution network in which controllable resources are rare. On the other hand, provided with appropriate incentives, the energy storage capability of electric vehicle offers a unique opportunity to facilitate the integration of distributed wind and solar power generation into power distribution system. The above trends call for thorough investigation and research on the interdependence between transportation system and power distribution system. This paper conducts a comprehensive survey on this line of research. The basic models of transportation system and power distribution system are introduced,especially the user equilibrium model, which describes the vehicular flow on each road segment and is not familiar to the readers in power system community. The modelling of interdependence across the two systems is highlighted.Taking into account such interdependence, applications ranging from long-term planning to short-term operation are reviewed with emphasis on comparing the description of traffic-power interdependence. Finally, an outlook of prospective directions and key technologies in future research is summarized.展开更多
Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown t...Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance （SPR） phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized.展开更多
Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and s...Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and spectroscopic techniques, but with the refractometric approach considered as well when the objective is of high measurement performance, particularly when the focus is on enhancing the measurand resolution. In this work, we address this subject, proposing and analyzing the characteristics of a fiber optic optrode relying on plasmonic interaction. A linearly tapered optical fiber tip is covered by a double overlay： the inner one - a silver thin film and over it - a dielectric layer, with this combination allowing to achieve, at a specific wavelength range, surface plasmonic resonance （SPR） interaction sensitive Typically, the interrogation of the SPR sensing to the refractive index of the surrounding medium. structures is performed, considering spectroscopic techniques, but in principle, a far better performance can be obtained, considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This is the approach which is studied here in the context of the proposed optical fiber optrode configuration. The analysis performed shows the combination of a silver inner layer with a dielectric titanium oxide layer with tuned thicknesses enables sensitive phase reading and allows the operation of the fiber optic optrode sensor in the third telecommunication wavelength window.展开更多
This paper develops a novel approach to track power system state evolution based on the maximum correntropy criterion,due to its robustness against non-Gaussian errors.It includes the temporal aspects on the estimatio...This paper develops a novel approach to track power system state evolution based on the maximum correntropy criterion,due to its robustness against non-Gaussian errors.It includes the temporal aspects on the estimation process within a maximum-correntropy-based extended Kalman filter(MCEKF),which is able to deal with both nonlinear supervisory control and data acquisition(SCADA)and phasor measurement unit(PMU)measurement models.By representing the behavior of the state variables with a nonparametric model within the kernel density estimation,it is possible to include abrupt state transitions as part of the process noise with non-Gaussian characteristics.Also,a novel strategy to update the size of Parzen windows in the kernel estimation is proposed to suppress the effects of suspect samples.By properly adjusting the kernel bandwidth,the proposed MCEKF keeps its accuracy during sudden load changes and contingencies,or in the presence of bad data.Simulations with IEEE test systems and the Brazilian interconnected system are carried out.The results show that the method deals with non-Gaussian noises in both the process and measurement,and provides accurate estimates of the system state under normal and abnormal conditions.展开更多
The proposed technique demonstrates a fiber ring resonator interrogated by an optical time domain reflectometer(OTDR),for intensity sensing.By using this methodology,a cavity round trip time of 2.85ms was obtained.For...The proposed technique demonstrates a fiber ring resonator interrogated by an optical time domain reflectometer(OTDR),for intensity sensing.By using this methodology,a cavity round trip time of 2.85ms was obtained.For a proof of concept,a long-period grating was inserted in the resonant cavity operating as a curvature sensing device.A novel signal processing approach was outlined,regarding to the logarithmic behavior of the OTDR.Through analyzing the experimental results,an increase in the measured sensitivities was obtained by increasing applied bending.With curvatures performed from 1.8 m^(-1) to 4.5 m^(-1),the sensitivity values ranged from 2.94 dB·km^(-1) to 5.15 dB·km^(-1).In its turn,the sensitivities obtained presented a linear behavior when studied as a function of the applied curvature,following a slope of 0.86×10-3 dB.The advantages of applying this technique were also discussed,demonstrating two similar fiber rings multiplexed in a series of configurations.展开更多
Dealing with scarcity events is nowadays gaining relevance in electricity market studies, as traditionally predictable generation and consumption patterns are fading. Policymakers and system planners use therefore ade...Dealing with scarcity events is nowadays gaining relevance in electricity market studies, as traditionally predictable generation and consumption patterns are fading. Policymakers and system planners use therefore adequacy studies to a) understand if the current market design will attract sufficient generation capacity to meet electricity demand in the future and b) to comprehend what drives system inadequacy or resource scarcity when future scenarios lack adequate capacity. This work addressed the latter and showcases a first in-its-kind rulebased methodology that filters scarcity events from a large set of electricity market simulations. In this proof-of-concept, a rule-mining algorithm is applied to outputs from ENTSO-E’s Pan-European electricity market model, which is run for 700 model scenarios, each covering 8760 time steps. The developed methodology shows how to unveil potential reasons behind scarcity events in an automated, interpretable, and scalable manner.展开更多
The purpose of the present work is to construct a reaction board based on fiber Bragg gratings （FBGs） that could be used for estimation of the 2D coordinates of the projection of center of gravity （CG） of an objec...The purpose of the present work is to construct a reaction board based on fiber Bragg gratings （FBGs） that could be used for estimation of the 2D coordinates of the projection of center of gravity （CG） of an object. The apparatus is consisted of a rigid equilateral triangular board mounted on three supports at the vertices, two of which have cantilevers instrumented with FBGs. When an object of known weight is placed on the board, the bending strain of the cantilevers is measured by a proportional wavelength shift of the FBGs. Applying the equilibrium conditions of a rigid body and proper calibration procedures, the wavelength shift is used to estimate the vertical reaction forces and moments of force at the supports and the coordinates of the object＇s CG projection on the board. This method can be used on a regular basis to estimate the CG of the human body or objects with complex geometry and density distribution. An example is provided for the estimation of the CG projection coordinates of two orthopaedic femur bone models, one intact, and the other with a hip stem implant encased. The clinical implications of changing the normal CG location by means of a prosthesis have been discussed.展开更多
基金Supported by Centre for Research in Health Informatics Systems and Technologies(CINTESIS)
文摘AIM: To identify demographic and clinical factors asso-ciated with disabling Crohn's disease (CD). METHODS: A systematic review and meta-analysisof observational studies, focusing on the factors that can predict the prognosis of different outcomes of CD was undertaken. PubMed, ISI Web of Knowledge and Scopus were searched to identify studies investigat-ing the above mentioned factors in adult patients with CD. Studies were eligible for inclusion if they describe prognostic factors in CD, with inclusion and exclusion criteria defined as follows. Studies with adult patients and CD, written in English and studying association between clinical factors and at least one prognosis out-come were included. Meta-analysis of effects was un-dertaken for the disabling disease outcome, using odds ratio (OR) to assess the effect of the different factors in the outcome. The statistical method used was Mantel-Haenszel for fixed effects. The 16-item quality assess-ment tool (QATSDD) was used to assess the quality of the studies (range: 0-42). RESULTS: Of the 913 papers initially selected, sixty studies were reviewed and three were included in the systematic review and meta-analysis. The global QA-TSDD scores of papers were 18, 21 and 22. Of a total of 1961 patients enrolled, 1332 (78%) were classified with disabling disease five years after diagnosis. In two studies, age at diagnosis was a factor associated with disabling disease five years after diagnosis. Individu-als under 40 years old had a higher risk of developing disabling disease. In two studies, patients who were treated with corticosteroids on the first flare developed disabling disease five years after diagnosis. Further, perianal disease was found to be relevant in all of the studies at two and five years after diagnosis. Finally, one study showed localization as a factor associated with disabling disease five years after diagnosis, with L3 being a higher risk factor. This meta-analysis showed a significantly higher risk of developing disabling dis-ease at five years after initial diagnosis among patients younger than 40 years of age (OR=2.47, 95%CI: 1.74-3.51), with initial steroid treatment for first flare (OR=2.42, 95%CI: 1.87-3.11) and with perianal dis-ease (OR = 2.00, 95%CI: 1.41-2.85).CONCLUSION: Age at diagnosis, perianal disease, ini-tial use of steroids and localization seem to be indepen-dent prognostic factors of disabling disease.
基金This work was supported by the Joint Research Fund in Smart Grid under cooperative agreement between the National Natural Science Foundation of China(NSFC)and State Grid Corporation of China(U1966601).
文摘In the conventional robust optimization(RO)context,the uncertainty is regarded as residing in a predetermined and fixed uncertainty set.In many applications,however,uncertainties are affected by decisions,making the current RO framework inapplicable.This paper investigates a class of two-stage RO problems that involve decision-dependent uncertainties.We introduce a class of polyhedral uncertainty sets whose right-hand-side vector has a dependency on the here-and-now decisions and seek to derive the exact optimal wait-and-see decisions for the second-stage problem.A novel iterative algorithm based on the Benders dual decomposition is proposed where advanced optimality cuts and feasibility cuts are designed to incorporate the uncertainty-decision coupling.The computational tractability,robust feasibility and optimality,and convergence performance of the proposed algorithm are guaranteed with theoretical proof.Four motivating application examples that feature the decision-dependent uncertainties are provided.Finally,the proposed solution methodology is verified by conducting case studies on the pre-disaster highway investment problem.
基金support from the Government of Russian Federation(Grant No.14.Z50.31.0004)The Tomsk State University Academic D.I.Mendeleev Fund Program.
文摘Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues.If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures.This technique turns biological tissues more transparent through two main mechanisms-tissue dehydration and refractive index(RI)matching between tissue compo-nents.Such matching is obtained by partial replacement of interstit ial water by a biocompat ible agent that presents higher RI and it can be completely rever sible by natural rehydration in vrivo or by assisted rehydration in ex vivo tissues.Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary.Using a simple method,based on collimated transmittance and thickness measurements made from muscle samples under treatment,we have estimated the diffusion properties of glucose,ethylene glycol(EG)and water that were used to perform such char acterization and discrimination.Comparing these properties with data from literature that characterize their diffusion in water we have observed that musde cell membrane permeability limits agent and water diffusion in the muscle.The same experi-mental data has allowed to calculate the optical dearing(OC)eficiency and make an inter-pretation of the internal changes that occurred in muscle during the treatments.The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a consider.able improvement of optical tomogr aphic techmiques with better contrast and in depth imaging.
基金supported by the ERDF (European Regional Development Fund) through the COMPETE Programme (operational programme for competitiveness)by the Portuguese National Strategic Reference Framework (NSRF) through the project CFC-5568
文摘In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.
文摘Staff scheduling and rostering problems, with application in several application areas, from transportation systems to hospitals, have been widely addressed by researchers. This is not the case of hospitality services, which have been forgotten by the quantitative research literature. The purpose of this paper is to provide some insights on the application of staff scheduling and rostering problems to hospitality management operations, reviewing existing approaches developed in other similar areas, such as nurse rostering or examining adaptable problem models, such as the tour scheduling.
基金supported in part by grants:RF Governmental contracts 11.519.11.2035,14.B37.21.0728,and 14.B37.11.0563FiDiPro,TEKES Program(40111/11),Finland+1 种基金SCOPES EC,Uzb/Switz/RF,Swiss NSF,IZ74ZO 137423/1RF President's grant"Scientific Schools",1177.2012.2.
文摘With the objective to study the variation of optical properties of rat muscle during optical clearing,we have performed a set of optical measurements from that kind of tissue.The.measurements performed were total tr ansmittance,ollimated transmit tance,specular reflec-tance and total reflectance.This set of measurements is suficient to determine diffuse reflectance and absorbance of the sample,also necessary to est imate the optical properties.All the per formed measurements and calculated quantities will be used later in inverse Monte Carlo(IMC)simu-lations to determine the evolution of the optical properties of muscle during treatments with ethylene glycol and glucose.The results obt ained with the measurements already provide some information about the optical c learing treatments applied to the muscle and translate the mechanisms of turning the tissue more transparent and sequence of regimes of optical clearing.
基金This work was funded by the Portuguese Foundation for Science and Technology(FCT),grant SFRH/BPD/71332/2010,Pest-OE/SAU/UI0617/2011 and UIDB/50014/2020The work was also developed in the context of Project QREN 33910 ARENA,a R&D project funded by ERDF through ON2 as part of the NSRF,and managed by IAPMEI-Agência para a Competitividade e Inovação,I.P..
文摘Purpose:Current Direct Observation(DO)methods are burdensome to the observer and relevant limitations can be identified on the outcome information.This study aims to characterize DO from the observers’point of view and to analyze the feasibility and usefulness of visual information in the form of video.Method:data collection was done with ten adult males,observed while performing different physical activities in an indoor court.Sessions were video recorded by two cameras.Three observers performed systematic observation,using SOPLAY,with different sampling rates.Inter observer’s agreement and with reference data was analyzed by Cohen’s Kappa statistic.Results:SOPLAY highest agreement between observers was 0.611 on vigorous category and walking category had the lowest 0.188.It doubles the time needed to annotate the video with pauses,but half of player’s behavior is preserved.Conclusion(s):using video to support DO permits to collect more accurate data and a more detailed behavior categorization is warranted.Developments in computer vision are expected to reduce the human efforts in DO methods.
文摘Wind energy is considered a hope in future as a clean and sustainable energy, as can be seen by the growing number of wind farms installed all over the world. With the huge proliferation of wind farms, as an alternative to the traditional fossil power generation, the economic issues dictate the necessity of monitoring systems to optimize the availability and profits. The relatively high cost of operation and maintenance associated to wind power is a major issue. Wind turbines are most of the time located in remote areas or offshore and these factors increase the referred operation and maintenance costs. Good maintenance strategies are needed to increase the health management of wind turbines. The objective of this paper is to show the application of neural networks to analyze all the wind turbine information to identify possible future failures, based on previous information of the turbine.
文摘This paper captures an engaging—and at times heated—Power-Globe(PG)discussion of evolving definitions of smart grid technologies.The exchange took place between December 2024 and January 2025.The primary objective of this paper is to clarify some of the ambiguities surrounding the term“smart grid”over the past two decades,as highlighted in the spirited PG debate.“Smart grid”has sometimes been advocated as a panacea to resolve the tension between competing objectives for the provision of electricity(specifically,making it reliable,clean,and affordable).This paper examines the term“smart grid”in terms of raw technical functionalities,applications,and use cases,some of which may get closer than others to meeting the aspirational promises.While smart technology should expand our menu of options,it will not absolve us of the need to make hard decisions.
文摘The most relevant aspects related to the phase mask dithering/moving method for the fabrication of complex Bragg grating designs are reviewed. Details for experimental implementation of this technique is presented, including theoretical analysis of the calibration functions for the correct dither/displacement. Results from tailored Bragg grating structures fabricated by this method are shown. Apodized Bragg gratings with modeled spatial profiles were implemented, resulting in side mode suppression levels of more than 20 dB in gratings showing transmission filtering level higher than 30 dB. Chirped gratings with the spectral bandwidth up to 4 nm, π-shift and sampled Bragg gratings with equalized peaks equally spaced by 0.8 nm （100 GHz） were also fabricated.
基金supported by the China Geological Survey under grant number[DD20160342]the China MOST-ESA Dragon Project-4 under grant number[32365]the National Science Foundation of China(NSFC)under grant number[41590852,41001264].
文摘COSMO-SkyMed is a constellation of four X-band high-resolution radar satellites with a minimum revisit period of 12 hours.These satellites can obtain ascending and descending synthetic aperture radar(SAR)images with very similar periods for use in the three-dimensional(3D)inversion of glacier velocities.In this paper,based on ascending and descending COSMO-SkyMed data acquired at nearly the same time,the surface velocity of the Yiga Glacier,located in the Jiali County,Tibet,China,is estimated in four directions using an offset tracking technique during the periods of 16 January to 3 February 2017 and 1 February to 19 February 2017.Through the geometrical relationships between the measurements and the SAR images,the least square method is used to retrieve the 3D components of the glacier surface velocity in the eastward,northward and upward directions.The results show that applying the offset tracking technique to COSMO-SkyMed images can be used to derive the true 3D velocity of a glacier’s surface.During the two periods,the Yiga Glacier had a stable velocity,and the maximum surface velocity,2.4 m/d,was observed in the middle portion of the glacier,which corresponds to the location of the steepest slope.
基金AI4REALNET(AI for REAL-world NET-work operation)project,which received funding from European Union’s Horizon Europe Research and Innovation programme under the Grant Agreement No 101119527Swiss State Secretariat for Education,Research and Innovation(SERI)Ferinar Moaidi was supported by FCT(Fundação para a Ciência e a Tecnologia)within the Ph.D.Grant 2023.04869.BD.
文摘The growing integration of renewable energy sources and the widespread electrification of the energy demand have significantly reduced the capacity margin of the electrical grid.This demands a more flexible approach to grid operation,for instance,combining real-time topology optimization and redispatching.Traditional expertdriven decision-making rules may become insufficient to manage the increasing complexity of real-time grid operations and derive remedial actions under the N-1 contingency.This work proposes a novel hybrid AI framework for power grid topology control that integrates genetic network programming(GNP),reinforcement learning,and decision trees.A new variant of GNP is introduced that is capable of evolving the decision-making rules by learning from data in a reinforcement learning framework.The graph-based evolutionary structure of GNP and decision trees enables transparent,traceable reasoning.The proposed method outperforms both a baseline expert system and a state-of-the-art deep reinforcement learning agent on the IEEE 118-bus system,achieving up to an 28%improvement in a key performance metric used in the Learning to Run a Power Network(L2RPN)competition.
基金supported by the ENFIELD(European Lighthouse to Manifest Trustworthy and Green AI)project,European Union’s Horizon Research and Innovation Programme(No.101120657).
文摘In a high-risk sector,such as power system,trans parency and interpretability are key principles for effectively deploying artificial intelligence(AI)in control rooms.There fore,this paper proposes a novel methodology,the evolving sym bolic model(ESM),which is dedicated to generating highly in terpretable data-driven models for dynamic security assessment(DSA),namely in system security classification(SC)and the def inition of preventive control actions.The ESM uses simulated annealing for a data-driven evolution of a symbolic model tem plate,enabling different cooperative learning schemes between humans and AI.The Madeira Island power system is used to validate the application of the ESM for DSA.The results show that the ESM has a classification accuracy comparable to pruned decision trees(DTs)while boasting higher global inter pretability.Moreover,the ESM outperforms an operator-de fined expert system and an artificial neural network in defining preventive control actions.
基金support by the Young Elite Scientists Program of CSEE (No. JLB-2018-95)the National Natural Science Foundation of China (No. 51621065, No. U1766203)+1 种基金the support by FEDER funds through COMPETE 2020by Portuguese funds through FCT, under SAICT-PAC/0004/2015 (No. POCI-01-0145-FEDER-016434), 02/SAICT/2017 (No. POCI-01-0145-FEDER-029803) and UID/EEA/50014/2019 (No. POCI-01-0145-FEDER-006961)
文摘The rapidly increasing penetration of electric vehicles(EVs) in modern metropolises has been witnessed during the past decade, inspired by financial subsidies as well as public awareness of climate change and environment pro-tection. Integrating charging facilities, especially highpower chargers in fast charging stations, into power distribution systems remarkably alters the traditional load flow pattern, and thus imposes great challenges on the operation of distribution network in which controllable resources are rare. On the other hand, provided with appropriate incentives, the energy storage capability of electric vehicle offers a unique opportunity to facilitate the integration of distributed wind and solar power generation into power distribution system. The above trends call for thorough investigation and research on the interdependence between transportation system and power distribution system. This paper conducts a comprehensive survey on this line of research. The basic models of transportation system and power distribution system are introduced,especially the user equilibrium model, which describes the vehicular flow on each road segment and is not familiar to the readers in power system community. The modelling of interdependence across the two systems is highlighted.Taking into account such interdependence, applications ranging from long-term planning to short-term operation are reviewed with emphasis on comparing the description of traffic-power interdependence. Finally, an outlook of prospective directions and key technologies in future research is summarized.
文摘Recently, many programs have been developed for simulation or analysis of the different parameters of light propagation in optical fibers, either for sensing or for communication purposes. In this paper, it is shown the COMSOL Multiphysics as a fairly robust and simple program, due to the existence of a graphical environment, to perform simulations with good accuracy. Results are compared with other simulation analysis, focusing on the surface plasmon resonance （SPR） phenomena for refractive index sensing in a D-type optical fiber, where the characteristics of the material layers, in terms of the type and thickness, and the residual fiber cladding thickness are optimized.
文摘Optical fiber optrodes are attractive sensing devices due to their ability to perform point measurement in remote locations. Mostly, they are oriented to biochemical sensing, quite often supported by fluorescent and spectroscopic techniques, but with the refractometric approach considered as well when the objective is of high measurement performance, particularly when the focus is on enhancing the measurand resolution. In this work, we address this subject, proposing and analyzing the characteristics of a fiber optic optrode relying on plasmonic interaction. A linearly tapered optical fiber tip is covered by a double overlay： the inner one - a silver thin film and over it - a dielectric layer, with this combination allowing to achieve, at a specific wavelength range, surface plasmonic resonance （SPR） interaction sensitive Typically, the interrogation of the SPR sensing to the refractive index of the surrounding medium. structures is performed, considering spectroscopic techniques, but in principle, a far better performance can be obtained, considering the reading of the phase of the light at a specific wavelength located within the spectral plasmonic resonance. This is the approach which is studied here in the context of the proposed optical fiber optrode configuration. The analysis performed shows the combination of a silver inner layer with a dielectric titanium oxide layer with tuned thicknesses enables sensitive phase reading and allows the operation of the fiber optic optrode sensor in the third telecommunication wavelength window.
基金supported by CNPq(No.308297/2018-0)CAPES and FAPESP(No.2016/19646-6)+1 种基金ERDF(COMPETE2020 Programme)FCT(POCI-01-0145-FEDER-016731 INFUSE)
文摘This paper develops a novel approach to track power system state evolution based on the maximum correntropy criterion,due to its robustness against non-Gaussian errors.It includes the temporal aspects on the estimation process within a maximum-correntropy-based extended Kalman filter(MCEKF),which is able to deal with both nonlinear supervisory control and data acquisition(SCADA)and phasor measurement unit(PMU)measurement models.By representing the behavior of the state variables with a nonparametric model within the kernel density estimation,it is possible to include abrupt state transitions as part of the process noise with non-Gaussian characteristics.Also,a novel strategy to update the size of Parzen windows in the kernel estimation is proposed to suppress the effects of suspect samples.By properly adjusting the kernel bandwidth,the proposed MCEKF keeps its accuracy during sudden load changes and contingencies,or in the presence of bad data.Simulations with IEEE test systems and the Brazilian interconnected system are carried out.The results show that the method deals with non-Gaussian noises in both the process and measurement,and provides accurate estimates of the system state under normal and abnormal conditions.
基金This work is financed by National Funds through the Portuguese funding agency,FCT-“Fundação para a Ciência e a Tecnologia”under Grant No.UID/EEA/50014/2019.
文摘The proposed technique demonstrates a fiber ring resonator interrogated by an optical time domain reflectometer(OTDR),for intensity sensing.By using this methodology,a cavity round trip time of 2.85ms was obtained.For a proof of concept,a long-period grating was inserted in the resonant cavity operating as a curvature sensing device.A novel signal processing approach was outlined,regarding to the logarithmic behavior of the OTDR.Through analyzing the experimental results,an increase in the measured sensitivities was obtained by increasing applied bending.With curvatures performed from 1.8 m^(-1) to 4.5 m^(-1),the sensitivity values ranged from 2.94 dB·km^(-1) to 5.15 dB·km^(-1).In its turn,the sensitivities obtained presented a linear behavior when studied as a function of the applied curvature,following a slope of 0.86×10-3 dB.The advantages of applying this technique were also discussed,demonstrating two similar fiber rings multiplexed in a series of configurations.
文摘Dealing with scarcity events is nowadays gaining relevance in electricity market studies, as traditionally predictable generation and consumption patterns are fading. Policymakers and system planners use therefore adequacy studies to a) understand if the current market design will attract sufficient generation capacity to meet electricity demand in the future and b) to comprehend what drives system inadequacy or resource scarcity when future scenarios lack adequate capacity. This work addressed the latter and showcases a first in-its-kind rulebased methodology that filters scarcity events from a large set of electricity market simulations. In this proof-of-concept, a rule-mining algorithm is applied to outputs from ENTSO-E’s Pan-European electricity market model, which is run for 700 model scenarios, each covering 8760 time steps. The developed methodology shows how to unveil potential reasons behind scarcity events in an automated, interpretable, and scalable manner.
文摘The purpose of the present work is to construct a reaction board based on fiber Bragg gratings （FBGs） that could be used for estimation of the 2D coordinates of the projection of center of gravity （CG） of an object. The apparatus is consisted of a rigid equilateral triangular board mounted on three supports at the vertices, two of which have cantilevers instrumented with FBGs. When an object of known weight is placed on the board, the bending strain of the cantilevers is measured by a proportional wavelength shift of the FBGs. Applying the equilibrium conditions of a rigid body and proper calibration procedures, the wavelength shift is used to estimate the vertical reaction forces and moments of force at the supports and the coordinates of the object＇s CG projection on the board. This method can be used on a regular basis to estimate the CG of the human body or objects with complex geometry and density distribution. An example is provided for the estimation of the CG projection coordinates of two orthopaedic femur bone models, one intact, and the other with a hip stem implant encased. The clinical implications of changing the normal CG location by means of a prosthesis have been discussed.
