Integrating multiple medical imaging techniques,including Magnetic Resonance Imaging(MRI),Computed Tomography,Positron Emission Tomography(PET),and ultrasound,provides a comprehensive view of the patient health status...Integrating multiple medical imaging techniques,including Magnetic Resonance Imaging(MRI),Computed Tomography,Positron Emission Tomography(PET),and ultrasound,provides a comprehensive view of the patient health status.Each of these methods contributes unique diagnostic insights,enhancing the overall assessment of patient condition.Nevertheless,the amalgamation of data from multiple modalities presents difficulties due to disparities in resolution,data collection methods,and noise levels.While traditional models like Convolutional Neural Networks(CNNs)excel in single-modality tasks,they struggle to handle multi-modal complexities,lacking the capacity to model global relationships.This research presents a novel approach for examining multi-modal medical imagery using a transformer-based system.The framework employs self-attention and cross-attention mechanisms to synchronize and integrate features across various modalities.Additionally,it shows resilience to variations in noise and image quality,making it adaptable for real-time clinical use.To address the computational hurdles linked to transformer models,particularly in real-time clinical applications in resource-constrained environments,several optimization techniques have been integrated to boost scalability and efficiency.Initially,a streamlined transformer architecture was adopted to minimize the computational load while maintaining model effectiveness.Methods such as model pruning,quantization,and knowledge distillation have been applied to reduce the parameter count and enhance the inference speed.Furthermore,efficient attention mechanisms such as linear or sparse attention were employed to alleviate the substantial memory and processing requirements of traditional self-attention operations.For further deployment optimization,researchers have implemented hardware-aware acceleration strategies,including the use of TensorRT and ONNX-based model compression,to ensure efficient execution on edge devices.These optimizations allow the approach to function effectively in real-time clinical settings,ensuring viability even in environments with limited resources.Future research directions include integrating non-imaging data to facilitate personalized treatment and enhancing computational efficiency for implementation in resource-limited environments.This study highlights the transformative potential of transformer models in multi-modal medical imaging,offering improvements in diagnostic accuracy and patient care outcomes.展开更多
This paper presents an efficient and reliable genetic algorithm (GA) based particle swarm optimization (PSO) tech- nique (hybrid GAPSO) for solving the economic dispatch (ED) problem in power systems. The non-linear c...This paper presents an efficient and reliable genetic algorithm (GA) based particle swarm optimization (PSO) tech- nique (hybrid GAPSO) for solving the economic dispatch (ED) problem in power systems. The non-linear characteristics of the generators, such as prohibited operating zones, ramp rate limits and non-smooth cost functions of the practical generator operation are considered. The proposed hybrid algorithm is demonstrated for three different systems and the performance is compared with the GA and PSO in terms of solution quality and computation efficiency. Comparison of results proved that the proposed algo- rithm can obtain higher quality solutions efficiently in ED problems. A comprehensive software package is developed using MATLAB.展开更多
Pervasive wireless computing and communication have created an ever-increasing demand for more radio spectrum. Since, most of the spectrum is underutilized, it motivated the introduction of the concept of cognitive ra...Pervasive wireless computing and communication have created an ever-increasing demand for more radio spectrum. Since, most of the spectrum is underutilized, it motivated the introduction of the concept of cognitive radios, a dynamic spectrum access enabling technology. The first stage of cognitive radio is to sense the environment and determine which parts of the spectrum are available. This is achieved through spectrum sensing. However, spectrum sensing poses the most fundamental challenge in cognitive radios. Moreover, cognitive radios suffer from many vulnerabilities and the security attacks can severely degrade the performance of cognitive radios. This paper surveys state-of-theart research on spectrum sensing and security threats in cognitive radios. Lastly, we also consider the analysis of issues related to spectrum handoffs in cognitive radios.展开更多
Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with appl...Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with applica-tions to point-of-load and isolated DC/DC converters,microprocessor power supplies,power-factor-correction rectifiers,and others.This paper summarizes some of the advances in the area,including approaches to realizations of high-per-formance,high-frequency digital pulse-width modulated(DPWM) controllers,related analysis,modeling and design techniques,as well as performance gains enabled by digital control such as dynamic response and efficiency improve-ments.Examples of experimentally demonstrated results are presented,together with pointers to areas of current and future research and development.展开更多
Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, t...Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, the application of Empirical Mode Decomposition(EMD) technique to analyze nonlinear and non-stationary signals has gained much attention. It is an empirical approach to decompose a signal into a set of oscillatory modes known as intrinsic mode functions(IMFs). In general, Hilbert transform is used in EMD for the identification of oscillatory signals. In this paper a new EMD algorithm is proposed using FFT to identify and extract the acoustic signals available in the underwater channel that are corrupted due to various ambient noises over a range of 100 Hz to 10 kHz in a shallow water region. Data for analysis are collected at a depth of 5 m and 10 m offshore Chennai at the Bay of Bengal. The algorithm is validated for different sets of known and unknown reference signals. It is observed that the proposed EMD algorithm identifies and extracts the reference signals against various ambient noises. Significant SNR improvement is also achieved for underwater acoustic signals.展开更多
Dear Editor,In this letter,we analyze the public discourse sentiments over time and seek to understand the salient patterns around COVID-19 vaccines and vaccination from social media data.Globally,more than 373 millio...Dear Editor,In this letter,we analyze the public discourse sentiments over time and seek to understand the salient patterns around COVID-19 vaccines and vaccination from social media data.Globally,more than 373 million people have been diagnosed with COVID-19 and 5.66 million have died from this disease by 2022.It continues to have a negative impact on human daily life and the global economic development till now,due to the lack of effective treatment of COVID-19 induced issues and prevention of transmission methods.展开更多
Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array r...Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency(RF) and digital domain for real time operation. This is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed(WDM) technology and a feasibility study to adapt these links for radar applications is carried out. This is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. This also includes performance evaluation of non-linear frequency modulation(NLFM) signals, known for better signal to noise ratio(SNR) to specific side lobe levels. NLFM waveforms are further analysed using pulse compression(PC) technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave(CW), pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.展开更多
This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the res...This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the resulted Boolean function in terms of truth table sequence. This algorithm was used to develop two classes of balanced Boolean functions, one of which has very good cryptographic properties:nl(f)=2 2k?1?2k+2k?2 (n=2k), with the sum-of-squares avalanche characteristic off satisfying σf=24k+23k+2+23k-2 and the absolute avalanche characteristic off satisfying σf=24k+23k+2+23k-2. This is the best result up to now compared to existing ones. Instead of bent sequences, starting from random Boolean functions was also tested in the algorithm. Experimental results showed that starting from bent sequences is highly superior to starting from random Boolean functions. Key words Boolean functions - Bent sequences - Nonlinearity - GAC - PC - Balancedness Document code A CLC number TP301.6展开更多
Dear Editor： There is accumulating evidence that human blood electronic circuit components and their application circuits become more and more important to cyborg implant/engineering, man-machine interface, hu- man ...Dear Editor： There is accumulating evidence that human blood electronic circuit components and their application circuits become more and more important to cyborg implant/engineering, man-machine interface, hu- man disease detection and healing, and artificial brain evolutionusl. Here, we report the first development of human plasma-based amplifier circuit in the dis- crete as well as integrated circuit （IC） configuration mode. Electrolytes in the human blood contain an enormous number of charge carriers such as positive and negative molecule/atom ions, which are electri- cally conducting media and therefore can be utilized for developing electronic circuit components and their application circuits. These electronic circuits obvi- ously have very high application impact potential towards bio-medical engineering and medical science and technology.展开更多
In the Internet of Things(IoT)scenario,many devices will communi-cate in the presence of the cellular network;the chances of availability of spec-trum will be very scary given the presence of large numbers of mobile u...In the Internet of Things(IoT)scenario,many devices will communi-cate in the presence of the cellular network;the chances of availability of spec-trum will be very scary given the presence of large numbers of mobile users and large amounts of applications.Spectrum prediction is very encouraging for high traffic next-generation wireless networks,where devices/machines which are part of the Cognitive Radio Network(CRN)can predict the spectrum state prior to transmission to save their limited energy by avoiding unnecessarily sen-sing radio spectrum.Long short-term memory(LSTM)is employed to simulta-neously predict the Radio Spectrum State(RSS)for two-time slots,thereby allowing the secondary node to use the prediction result to transmit its information to achieve lower waiting time hence,enhanced performance capacity.A frame-work of spectral transmission based on the LSTM prediction is formulated,named as positive prediction and sensing-based spectrum access.The proposed scheme provides an average maximum waiting time gain of 2.88 ms.The proposed scheme provides 0.096 bps more capacity than a conventional energy detector.展开更多
A double stage AC/DC sequential high voltage reactor has been developed to study the decomposition of benzene in the air stream at atmospheric pressure. The removal efficiency was measured as a function of ozonation, ...A double stage AC/DC sequential high voltage reactor has been developed to study the decomposition of benzene in the air stream at atmospheric pressure. The removal efficiency was measured as a function of ozonation, flow recycling, and flow recirculation. Ozonation in the inlet, and recycling of the exhaust stream increased the removal of benzene, also with increasing of specific input energy(J l^-1) the effect of inlet flow ozonation on benzene decomposition was enhanced. The highest removal efficiency was obtained up to >99% in recirculation six times,while CO2 selectivity reached 99.9% and energy efficiency was 0.59 g kWh^-1. O3 production/decomposition > production of OH radicals > electronic and ionic collisions were indicated as the main mechanisms influencing benzene abatement in this research.展开更多
This paper extends the Non-Circular MUltiple SIgnal Classification(MUSIC)(NC-MUSIC) method for the common array geometries including Uniform Circular Arrays(UCAs) and Uniform Rectangular Arrays(URAs),which enables the...This paper extends the Non-Circular MUltiple SIgnal Classification(MUSIC)(NC-MUSIC) method for the common array geometries including Uniform Circular Arrays(UCAs) and Uniform Rectangular Arrays(URAs),which enables the algorithm to estimate 2-D Direction Of Arrival(DOA).A comparison between UCAs and URAs of NC-MUSIC is made in this paper.The simulations show that the NC-MUSIC method doubles the maximum estimation number of standard MUSIC.Using non-circular signals,the performance of URAs is improved remarkably while the improvement of UCAs is not so significantly.Moreover,the influence of arrays structures on the NC-MUSIC method is discussed.展开更多
A complete understanding of laser interaction with materials is still a matter of trials and adjustments.The real physical processes of laser beam interaction(drilling,cutting,welding,or being used as a directed energ...A complete understanding of laser interaction with materials is still a matter of trials and adjustments.The real physical processes of laser beam interaction(drilling,cutting,welding,or being used as a directed energy weapon application)with materials are very complex.Problem of laser interaction with materials presents many difficulties,both from modeling as well as from experimental sides.One would expect a reasonable description of the main phenomena occurring during laser interaction,but this is complicated because many of physical processes equally contribute to the development of conservation equations,producing drawback because of a great complexity of the equations to be solved.In most instances,this leads to formulation of a model needed to be solved numerically.A lack of pertinent experimental data to compare with,forces one to simplify some equations and use previous analytical and computational work done in this field.In Part IV here,we cover the absorption coefficient,which can be derived from the material’s dielectric function and conductivity,determines the absorption of light as a function of depth.However,the specific mechanisms by which the absorption occurs will depend on the type of material.In general,photons will couple into the available electronic or vibrational states in the material depending on the photon energy.In insulators and semiconductors,the absorption of laser light predominantly occurs through resonant excitations such as transitions of valence band electrons to the conduction band(inter-band transitions)or within bands(inter-sub-band transitions).In this part we cover all the aspect of the“Mathematical of Laser Absorption in Metals”that fits into this part of our suggesting short courses in different parts so far.展开更多
With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in r...With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.As we indicated in this part of short course mainly Part I and Part II,we have started a series of articles on the subject of Materials Responses to High Power Energy Lasers and continue these series by starting to introduce the Laser Light Propagation into materials.In this part namely Part III,we are discussing,one of the most important effects of intense laser irradiation is the conversion of the optical energy in the beam into thermal energy in the material.This is the basis of many applications of lasers,such as welding and cutting.We shall summarize here this thermal response.It is basically a classical problem,namely heat flow,in a usual manner of heat conduction,we show solutions to the equation which governs the flow of heat and discuss change of phases in targeting material from solid to liquid and finally vapor and plasma stages step by step.展开更多
With recent attention to high power energy and its interaction with materials of different types,both in industry and military application,this paper covers a short review course into subject of materials response in ...With recent attention to high power energy and its interaction with materials of different types,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.As we indicated in this part of short course mainly Part I,we have stated of series of article on the subject of Materials Responses to High Power Energy Lasers and continue these series by starting to introduce the Laser Light Propagation either in vacuum or through atmosphere by also introducing thermal blooming effects as well,then we cover,subjects such as Optical Reflectivity,thermal responses of materials by looking at Latent Heat of Fusion as well as Vaporization,No Phase Changes in both Semi-Infinite Solid or Slab of Finite Thickness,Melting and Vaporization and then move on to Effects of Pulsed or Continuous Laser Radiation as well,throughout of next few parts that we report them as further Short Courses content.展开更多
With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in r...With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.We describe the radiation wave,propagation wave in a complex form solution,utilizing Maxwell’s equation within dielectric materials,then we look at compression of materials,due to melting and boiling driven by heat transfer energy radiation and conduction induced by these high power energy lasers such is Nd Ya and CO2 lasers with wavelengths anywhere from 1.6μm to 10.6μm.We also look at Hugoniot Elastic Limit(HEL)and spall strength of materials,with the energy lasers dueling with targeted material,where also,physics of hydrodynamics effects due to strong shock is involved.We also talk about certain available computer that allows end user to calculate these phenomena in 1-D to 3-D type scenarios.Although covering all these above issues that are very lengthy write-up proposition,we have tried to be very brief,yet to the point presentation in form of a short course in this paper.展开更多
Subsurface cavities are very susceptible subsurface locations for down-lifting of a dam construction.In order to detect the low-density zones of a power plant a micro-gravity survey was conducted in a site considered ...Subsurface cavities are very susceptible subsurface locations for down-lifting of a dam construction.In order to detect the low-density zones of a power plant a micro-gravity survey was conducted in a site considered for construction of a power plant site in Iran.First we gain the residual anomalies through bouger anomalies and then we design an Artificial Neural Network(ANN)which is trained by a set of training data.The ANN was tested for both synthetic and real data.For real data some suitable features are derivate from residual anomalies and applied to展开更多
In this paper,we propose improved approaches for two-dimensional(2 D) direction-of-arrival(DOA) estimation for a uniform rectangular array(URA).Unlike the conventional eigenstructure-based estimation approaches such a...In this paper,we propose improved approaches for two-dimensional(2 D) direction-of-arrival(DOA) estimation for a uniform rectangular array(URA).Unlike the conventional eigenstructure-based estimation approaches such as Multiple Signals Classification(MUSIC) and Estimation of Signal Parameters via Rotational Invariance Technique(ESPRIT),the proposed approaches estimate signal and noise subspaces with Nystr?m approximation,which only need to calculate two sub-matrices of the whole sample covariance matrix and avoid the need to directly calculate the eigenvalue decomposition(EVD) of the sample covariance matrix.Hence,the proposed approaches can improve the computational efficiency greatly for large-scale URAs.Numerical results verify the reliability and efficiency of the proposed approaches.展开更多
基金supported by the Deanship of Research and Graduate Studies at King Khalid University under Small Research Project grant number RGP1/139/45.
文摘Integrating multiple medical imaging techniques,including Magnetic Resonance Imaging(MRI),Computed Tomography,Positron Emission Tomography(PET),and ultrasound,provides a comprehensive view of the patient health status.Each of these methods contributes unique diagnostic insights,enhancing the overall assessment of patient condition.Nevertheless,the amalgamation of data from multiple modalities presents difficulties due to disparities in resolution,data collection methods,and noise levels.While traditional models like Convolutional Neural Networks(CNNs)excel in single-modality tasks,they struggle to handle multi-modal complexities,lacking the capacity to model global relationships.This research presents a novel approach for examining multi-modal medical imagery using a transformer-based system.The framework employs self-attention and cross-attention mechanisms to synchronize and integrate features across various modalities.Additionally,it shows resilience to variations in noise and image quality,making it adaptable for real-time clinical use.To address the computational hurdles linked to transformer models,particularly in real-time clinical applications in resource-constrained environments,several optimization techniques have been integrated to boost scalability and efficiency.Initially,a streamlined transformer architecture was adopted to minimize the computational load while maintaining model effectiveness.Methods such as model pruning,quantization,and knowledge distillation have been applied to reduce the parameter count and enhance the inference speed.Furthermore,efficient attention mechanisms such as linear or sparse attention were employed to alleviate the substantial memory and processing requirements of traditional self-attention operations.For further deployment optimization,researchers have implemented hardware-aware acceleration strategies,including the use of TensorRT and ONNX-based model compression,to ensure efficient execution on edge devices.These optimizations allow the approach to function effectively in real-time clinical settings,ensuring viability even in environments with limited resources.Future research directions include integrating non-imaging data to facilitate personalized treatment and enhancing computational efficiency for implementation in resource-limited environments.This study highlights the transformative potential of transformer models in multi-modal medical imaging,offering improvements in diagnostic accuracy and patient care outcomes.
文摘This paper presents an efficient and reliable genetic algorithm (GA) based particle swarm optimization (PSO) tech- nique (hybrid GAPSO) for solving the economic dispatch (ED) problem in power systems. The non-linear characteristics of the generators, such as prohibited operating zones, ramp rate limits and non-smooth cost functions of the practical generator operation are considered. The proposed hybrid algorithm is demonstrated for three different systems and the performance is compared with the GA and PSO in terms of solution quality and computation efficiency. Comparison of results proved that the proposed algo- rithm can obtain higher quality solutions efficiently in ED problems. A comprehensive software package is developed using MATLAB.
文摘Pervasive wireless computing and communication have created an ever-increasing demand for more radio spectrum. Since, most of the spectrum is underutilized, it motivated the introduction of the concept of cognitive radios, a dynamic spectrum access enabling technology. The first stage of cognitive radio is to sense the environment and determine which parts of the spectrum are available. This is achieved through spectrum sensing. However, spectrum sensing poses the most fundamental challenge in cognitive radios. Moreover, cognitive radios suffer from many vulnerabilities and the security attacks can severely degrade the performance of cognitive radios. This paper surveys state-of-theart research on spectrum sensing and security threats in cognitive radios. Lastly, we also consider the analysis of issues related to spectrum handoffs in cognitive radios.
基金The work presented in this paper has been supported by industrial sponsors of the Colorado Power Electronics Center(CoPEC).The authors would like to acknowledge CoPEC graduate students for significant contributions to the results reported in this paper.
文摘Over the last decade,practical digital control of high-frequency switched-mode power converters has moved from proof-of-concept demonstrations to controller chips commercially available from multiple vendors,with applica-tions to point-of-load and isolated DC/DC converters,microprocessor power supplies,power-factor-correction rectifiers,and others.This paper summarizes some of the advances in the area,including approaches to realizations of high-per-formance,high-frequency digital pulse-width modulated(DPWM) controllers,related analysis,modeling and design techniques,as well as performance gains enabled by digital control such as dynamic response and efficiency improve-ments.Examples of experimentally demonstrated results are presented,together with pointers to areas of current and future research and development.
文摘Sonar generated acoustic signals transmitted in underwater channel for distant communications are affected by numerous factors like ambient noise, making them nonlinear and non-stationary in nature. In recent years, the application of Empirical Mode Decomposition(EMD) technique to analyze nonlinear and non-stationary signals has gained much attention. It is an empirical approach to decompose a signal into a set of oscillatory modes known as intrinsic mode functions(IMFs). In general, Hilbert transform is used in EMD for the identification of oscillatory signals. In this paper a new EMD algorithm is proposed using FFT to identify and extract the acoustic signals available in the underwater channel that are corrupted due to various ambient noises over a range of 100 Hz to 10 kHz in a shallow water region. Data for analysis are collected at a depth of 5 m and 10 m offshore Chennai at the Bay of Bengal. The algorithm is validated for different sets of known and unknown reference signals. It is observed that the proposed EMD algorithm identifies and extracts the reference signals against various ambient noises. Significant SNR improvement is also achieved for underwater acoustic signals.
基金This work was funded by the Deanship of Scientific Research(DSR)at King Abdulaziz University,Jeddah,Saudi Arabia(GCV19-37-1441).
文摘Dear Editor,In this letter,we analyze the public discourse sentiments over time and seek to understand the salient patterns around COVID-19 vaccines and vaccination from social media data.Globally,more than 373 million people have been diagnosed with COVID-19 and 5.66 million have died from this disease by 2022.It continues to have a negative impact on human daily life and the global economic development till now,due to the lack of effective treatment of COVID-19 induced issues and prevention of transmission methods.
文摘Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency(RF) and digital domain for real time operation. This is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed(WDM) technology and a feasibility study to adapt these links for radar applications is carried out. This is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. This also includes performance evaluation of non-linear frequency modulation(NLFM) signals, known for better signal to noise ratio(SNR) to specific side lobe levels. NLFM waveforms are further analysed using pulse compression(PC) technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave(CW), pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.
文摘This paper proposes a practical algorithm for systematically generating strong Boolean functions (f:GF(2) n →GF(2)) with cryptographic meaning. This algorithm takes bent function as input and directly outputs the resulted Boolean function in terms of truth table sequence. This algorithm was used to develop two classes of balanced Boolean functions, one of which has very good cryptographic properties:nl(f)=2 2k?1?2k+2k?2 (n=2k), with the sum-of-squares avalanche characteristic off satisfying σf=24k+23k+2+23k-2 and the absolute avalanche characteristic off satisfying σf=24k+23k+2+23k-2. This is the best result up to now compared to existing ones. Instead of bent sequences, starting from random Boolean functions was also tested in the algorithm. Experimental results showed that starting from bent sequences is highly superior to starting from random Boolean functions. Key words Boolean functions - Bent sequences - Nonlinearity - GAC - PC - Balancedness Document code A CLC number TP301.6
文摘Dear Editor： There is accumulating evidence that human blood electronic circuit components and their application circuits become more and more important to cyborg implant/engineering, man-machine interface, hu- man disease detection and healing, and artificial brain evolutionusl. Here, we report the first development of human plasma-based amplifier circuit in the dis- crete as well as integrated circuit （IC） configuration mode. Electrolytes in the human blood contain an enormous number of charge carriers such as positive and negative molecule/atom ions, which are electri- cally conducting media and therefore can be utilized for developing electronic circuit components and their application circuits. These electronic circuits obvi- ously have very high application impact potential towards bio-medical engineering and medical science and technology.
文摘In the Internet of Things(IoT)scenario,many devices will communi-cate in the presence of the cellular network;the chances of availability of spec-trum will be very scary given the presence of large numbers of mobile users and large amounts of applications.Spectrum prediction is very encouraging for high traffic next-generation wireless networks,where devices/machines which are part of the Cognitive Radio Network(CRN)can predict the spectrum state prior to transmission to save their limited energy by avoiding unnecessarily sen-sing radio spectrum.Long short-term memory(LSTM)is employed to simulta-neously predict the Radio Spectrum State(RSS)for two-time slots,thereby allowing the secondary node to use the prediction result to transmit its information to achieve lower waiting time hence,enhanced performance capacity.A frame-work of spectral transmission based on the LSTM prediction is formulated,named as positive prediction and sensing-based spectrum access.The proposed scheme provides an average maximum waiting time gain of 2.88 ms.The proposed scheme provides 0.096 bps more capacity than a conventional energy detector.
文摘A double stage AC/DC sequential high voltage reactor has been developed to study the decomposition of benzene in the air stream at atmospheric pressure. The removal efficiency was measured as a function of ozonation, flow recycling, and flow recirculation. Ozonation in the inlet, and recycling of the exhaust stream increased the removal of benzene, also with increasing of specific input energy(J l^-1) the effect of inlet flow ozonation on benzene decomposition was enhanced. The highest removal efficiency was obtained up to >99% in recirculation six times,while CO2 selectivity reached 99.9% and energy efficiency was 0.59 g kWh^-1. O3 production/decomposition > production of OH radicals > electronic and ionic collisions were indicated as the main mechanisms influencing benzene abatement in this research.
文摘This paper extends the Non-Circular MUltiple SIgnal Classification(MUSIC)(NC-MUSIC) method for the common array geometries including Uniform Circular Arrays(UCAs) and Uniform Rectangular Arrays(URAs),which enables the algorithm to estimate 2-D Direction Of Arrival(DOA).A comparison between UCAs and URAs of NC-MUSIC is made in this paper.The simulations show that the NC-MUSIC method doubles the maximum estimation number of standard MUSIC.Using non-circular signals,the performance of URAs is improved remarkably while the improvement of UCAs is not so significantly.Moreover,the influence of arrays structures on the NC-MUSIC method is discussed.
文摘A complete understanding of laser interaction with materials is still a matter of trials and adjustments.The real physical processes of laser beam interaction(drilling,cutting,welding,or being used as a directed energy weapon application)with materials are very complex.Problem of laser interaction with materials presents many difficulties,both from modeling as well as from experimental sides.One would expect a reasonable description of the main phenomena occurring during laser interaction,but this is complicated because many of physical processes equally contribute to the development of conservation equations,producing drawback because of a great complexity of the equations to be solved.In most instances,this leads to formulation of a model needed to be solved numerically.A lack of pertinent experimental data to compare with,forces one to simplify some equations and use previous analytical and computational work done in this field.In Part IV here,we cover the absorption coefficient,which can be derived from the material’s dielectric function and conductivity,determines the absorption of light as a function of depth.However,the specific mechanisms by which the absorption occurs will depend on the type of material.In general,photons will couple into the available electronic or vibrational states in the material depending on the photon energy.In insulators and semiconductors,the absorption of laser light predominantly occurs through resonant excitations such as transitions of valence band electrons to the conduction band(inter-band transitions)or within bands(inter-sub-band transitions).In this part we cover all the aspect of the“Mathematical of Laser Absorption in Metals”that fits into this part of our suggesting short courses in different parts so far.
文摘With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.As we indicated in this part of short course mainly Part I and Part II,we have started a series of articles on the subject of Materials Responses to High Power Energy Lasers and continue these series by starting to introduce the Laser Light Propagation into materials.In this part namely Part III,we are discussing,one of the most important effects of intense laser irradiation is the conversion of the optical energy in the beam into thermal energy in the material.This is the basis of many applications of lasers,such as welding and cutting.We shall summarize here this thermal response.It is basically a classical problem,namely heat flow,in a usual manner of heat conduction,we show solutions to the equation which governs the flow of heat and discuss change of phases in targeting material from solid to liquid and finally vapor and plasma stages step by step.
文摘With recent attention to high power energy and its interaction with materials of different types,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.As we indicated in this part of short course mainly Part I,we have stated of series of article on the subject of Materials Responses to High Power Energy Lasers and continue these series by starting to introduce the Laser Light Propagation either in vacuum or through atmosphere by also introducing thermal blooming effects as well,then we cover,subjects such as Optical Reflectivity,thermal responses of materials by looking at Latent Heat of Fusion as well as Vaporization,No Phase Changes in both Semi-Infinite Solid or Slab of Finite Thickness,Melting and Vaporization and then move on to Effects of Pulsed or Continuous Laser Radiation as well,throughout of next few parts that we report them as further Short Courses content.
文摘With recent attention to high power energy and its interaction with materials of different type,both in industry and military application,this paper covers a short review course into subject of materials response in respect to such high power energy lasers.In this paper,we are covering laser interaction with solid and going through steps of phase changes,from solid to liquid and finally vapor stage.We describe the radiation wave,propagation wave in a complex form solution,utilizing Maxwell’s equation within dielectric materials,then we look at compression of materials,due to melting and boiling driven by heat transfer energy radiation and conduction induced by these high power energy lasers such is Nd Ya and CO2 lasers with wavelengths anywhere from 1.6μm to 10.6μm.We also look at Hugoniot Elastic Limit(HEL)and spall strength of materials,with the energy lasers dueling with targeted material,where also,physics of hydrodynamics effects due to strong shock is involved.We also talk about certain available computer that allows end user to calculate these phenomena in 1-D to 3-D type scenarios.Although covering all these above issues that are very lengthy write-up proposition,we have tried to be very brief,yet to the point presentation in form of a short course in this paper.
文摘Subsurface cavities are very susceptible subsurface locations for down-lifting of a dam construction.In order to detect the low-density zones of a power plant a micro-gravity survey was conducted in a site considered for construction of a power plant site in Iran.First we gain the residual anomalies through bouger anomalies and then we design an Artificial Neural Network(ANN)which is trained by a set of training data.The ANN was tested for both synthetic and real data.For real data some suitable features are derivate from residual anomalies and applied to
基金supported by"the Fundamental Research Funds for the Central Universities No.2017JBM016"
文摘In this paper,we propose improved approaches for two-dimensional(2 D) direction-of-arrival(DOA) estimation for a uniform rectangular array(URA).Unlike the conventional eigenstructure-based estimation approaches such as Multiple Signals Classification(MUSIC) and Estimation of Signal Parameters via Rotational Invariance Technique(ESPRIT),the proposed approaches estimate signal and noise subspaces with Nystr?m approximation,which only need to calculate two sub-matrices of the whole sample covariance matrix and avoid the need to directly calculate the eigenvalue decomposition(EVD) of the sample covariance matrix.Hence,the proposed approaches can improve the computational efficiency greatly for large-scale URAs.Numerical results verify the reliability and efficiency of the proposed approaches.
