Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is signif...Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is significantly affected by the substrate orientation and the growth method. The photoelectric properties of GaAs epilayers grown on Si (211) substrates deposited by using a two-step growth method are improved. These results indicate that GaAs epilayers grown on Si (100) and Si (211) substrates by using two-step growth method are promising for potential applications in high-speed and high-frequency photoelectric devices.展开更多
The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is l...The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is limitation in cell resources due to inter-cell interference (ICI). Soft Frequency Reuse is ICI mitigation scheme that controls the distribution of resources between users. In this paper, the Impact of four CAC schemes (Cutoff Priority scheme (CP), Uniform Fractional Guard Channel (UFGC), Limited Fractional Guard Channel (LFGC), New Call Bounding (NCB) scheme) at cell-edge have investigated using queuing analysis in a comparative manner. The comparison is based on two criteria. The first criterion guarantees a particular level of service to already admitted users while trying to optimize the revenue obtained. The second criterion determines the minimum of number of radio resources that provides hard constraints in both of blocking and dropping probabilities. The four schemes are compared at different scenarios of new and handover call arrival rates.展开更多
The effect of tensile uniaxial strain on the non-parabolic electronic band structure of armchair graphene nanoribbon（AGNR） is investigated.In addition,the density of states and the carrier statistic based on the tig...The effect of tensile uniaxial strain on the non-parabolic electronic band structure of armchair graphene nanoribbon（AGNR） is investigated.In addition,the density of states and the carrier statistic based on the tight-binding Hamiltonian are modeled analytically.It is found that the property of AGNR in the non-parabolic band region is varied by the strain.The tunable energy band gap in AGNR upon strain at the minimum energy is described for each of n-AGNR families in the non-parabolic approximation.The behavior of AGNR in the presence of strain is attributed to the breakable AGNR electronic band structure,which varies the physical properties from its normality.The linear relation between the energy gap and the electrical properties is featured to further explain the characteristic of the deformed AGNR upon strain.展开更多
In this paper,a high gain and directional coplanarwaveguide(CPW)-fed ultra-wideband(UWB)planar antenna with a new frequency selective surface(FSS)unit cells design is proposed for UWB applications.The proposed UWB ant...In this paper,a high gain and directional coplanarwaveguide(CPW)-fed ultra-wideband(UWB)planar antenna with a new frequency selective surface(FSS)unit cells design is proposed for UWB applications.The proposed UWB antenna was designed based on the Mercedes artistic-shaped planar(MAP)antenna.The antenna consisted of a circular ring embedded with three straight legs for antenna impedance bandwidth improvement.The modelled FSS used the integration of a two parallel conductive metallic patch with a circular loop structure.The FSS provided a UWB stopband filter response covering a bandwidth of 10.5 GHz,for frequencies from 2.2 to 12.7 GHz.The proposed FSS had a compact physical dimension of 5 mm×5 mm×1.6 mm,with a printed array of 19×19 FSS unit cells.The FSS unit cells were printed on only one side of the dielectric FR4 substrate and placed as a sandwich between the antenna and the reflector ground plane.An equivalent circuit configuration(ECC)was used to verify the FSS unit cell structure’s performance.The simulated results indicated that the UWB MAP antenna and FSS reflector provided a fractional bandwidth of 136%and a high gain of 11.5 dB at 8.5 GHz with an acceptable radiation efficiency of 89%.Furthermore,the gain was improved across the operating band and kept between 8.3 and 11.5 dB.The proposed antenna was in good agreement between theoretical and experimental results and offered a wide enough bandwidth for UWB and vehicle applications.展开更多
The fabrication and performance of 160-nm gate-length metamorphic AlInAs/GaInAs high electron mobility transistors （mHEMTs） grown on GaAs substrate by metal organic chemical vapour deposition （MOCVD） are reported....The fabrication and performance of 160-nm gate-length metamorphic AlInAs/GaInAs high electron mobility transistors （mHEMTs） grown on GaAs substrate by metal organic chemical vapour deposition （MOCVD） are reported. By using a novel combined optical and e-beam photolithography technology, submicron mHEMTs devices have been achieved. The devices exhibit good DC and RF performance. The maximum current density was 817 mA/mm and the maximum transconductance was 828 mS/mm. The non-alloyed Ohmic contact resistance Rc was as low as 0.02 Ω- ram. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 146 GHz and 189 GHz, respectively. This device has the highest fT yet reported for a 160-nm gate-length HEMTs grown by MOCVD. The output conductance is 28.9 mS/mm, which results in a large voltage gain of 28.6, Also, an input capacitance to gate-drain feedback capacitance ratio, Cgs/Cgd, of 4.3 is obtained in the device.展开更多
The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like nor...The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like normalized advancing index (NAI) and complete transmission time (CTT). The simulations are done for a simple single-hop-topology (sender-router-receiver). The outcomes of this protocol are excellent and, in most cases, better than other approaches. The excellent properties of our proposed protocol were possible through tracking the available slow-start threshold. We achieved performance improvement, minimized end-to-end delay and large reduction in transmission time. DCM+ was able to combine many advantages at same time of the protocols NewReno and Westwood+. The results show, that DCM+ is extremely adequate for different types of networks. Feedback as main principle of control theory was used to control the congestion in the network. The parameters Round-Trip-Time (RTT) and Retransmission Timeout (RTO) are used as feedback signals to adjust the next congestion window (cwnd).展开更多
This article presents an integrated current mode configurable analog block(CAB)system for field-programmable analog array(FPAA).The proposed architecture is based on the complementary metal-oxide semiconductor(CMOS)tr...This article presents an integrated current mode configurable analog block(CAB)system for field-programmable analog array(FPAA).The proposed architecture is based on the complementary metal-oxide semiconductor(CMOS)transistor level design where MOSFET transistors operating in the saturation region are adopted.The proposed CAB architecture is designed to implement six of thewidely used current mode operations in analog processing systems:addition,subtraction,integration,multiplication,division,and pass operation.The functionality of the proposed CAB is demonstrated through these six operations,where each operation is chosen based on the user’s selection in the CAB interface system.The architecture of the CAB system proposes an optimized way of designing and integrating only three functional cells with the interface circuitry to achieve the six operations.Furthermore,optimized programming and digital tuning circuitry are implemented in the architecture to control and interface with the functional cells.Moreover,these designed programming and tuning circuitries play an essential role in optimizing the performance of the proposed design.Simulation of the proposed CMOS Transistor Based CAB system is carried out using Tanner EDA Tools in 0.35μm standard CMOS technology.The design uses a±1.5 V power supply and results in maximum 3 dB bandwidth of 34.9 MHz and an approximate size of 0.0537 mm2.This demonstrates the advantages of the design over the current state-of-the-art designs presented for comparison in this article.Consequently,the proposed design has a clear aspect of simplicity,low power consumption,and high bandwidth operation,which makes it a suitable candidate for mobile telecommunications applications.展开更多
BACKGROUND Liver cancer is the 6 th most common cancer in the world and the 4 th most common death from cancer worldwide.Hepatic radioembolization is a minimally invasive treatment involving intraarterial administrati...BACKGROUND Liver cancer is the 6 th most common cancer in the world and the 4 th most common death from cancer worldwide.Hepatic radioembolization is a minimally invasive treatment involving intraarterial administration of radioembolic microspheres.AIM To develop a neutron-activated,biodegradable and theranostics samarium-153 acetylacetonate(153SmAcAc)-poly-L-lactic acid(PLLA)microsphere for intraarterial radioembolization of hepatic tumors.METHODS Microspheres with different concentrations of 152SmAcAc(i.e.,100%,150%,175%and 200%w/w)were prepared by solvent evaporation method.The microspheres were then activated using a nuclear reactor in a neutron flux of 2×10^12n/cm^2/s^1,converting 152Sm to Samarium-153(153)Sm)via 152Sm(n,γ) 153Sm reaction.The SmAcAc-PLLA microspheres before and after neutron activation were characterized using scanning electron microscope,energy dispersive X-ray spectroscopy,particle size analysis,Fourier transform infrared spectroscopy,thermo-gravimetric analysis and gamma spectroscopy.The in-vitro radiolabeling efficiency was also tested in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.RESULTS The SmAcAc-PLLA microspheres with different SmAcAc contents remained spherical before and after neutron activation.The mean diameter of the microspheres was about 35μm.Specific activity achieved for 153SmAcAc-PLLA microspheres with 100%,150%,175%and 200%(w/w)SmAcAc after 3 h neutron activation were 1.7±0.05,2.5±0.05,2.7±0.07,and 2.8±0.09 GBq/g,respectively.The activity of per microspheres were determined as 48.36±1.33,74.10±1.65,97.87±2.48,and 109.83±3.71 Bq for 153SmAcAc-PLLA microspheres with 100%,150%,175%and 200%(w/w)SmAcAc.The energy dispersive X-ray and gamma spectrometry showed that no elemental and radioactive impurities present in the microspheres after neutron activation.Retention efficiency of 153Sm in the SmAcAc-PLLA microspheres was excellent(approximately 99%)in both 0.9%sodium chloride solution and human blood plasma over a duration of 550 h.CONCLUSION The 153SmAcAc-PLLA microsphere is potentially useful for hepatic radioembolization due to their biodegradability,favorable physicochemical characteristics and excellent radiolabeling efficiency.The synthesis of the formulation does not involve ionizing radiation and hence reducing the complication and cost of production.展开更多
We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used a...We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used as an H-field reflector to direct more H-field to each resonator, and the L-matching network is employed to match the 50 Ω of the feed cable at 13.56 MHz. Two identical resonators with dimensions of 30 cm × 15 cm are separated by 50 cm, and the resulting transmission efficiency is about ?12.3 dB at 13.56 MHz. This is about 4.2 dB higher than the resonators without the ferrite plate.展开更多
Photovoltaics(PV-also called solar photovoltaic devices)are used to harness the power of the sun via the electronic process that occurs within semiconductor cells.The solar energy is absorbed by the cells,which causes...Photovoltaics(PV-also called solar photovoltaic devices)are used to harness the power of the sun via the electronic process that occurs within semiconductor cells.The solar energy is absorbed by the cells,which causes the electrons to break away from their atoms,allowing them to flow within the material to produce electricity.This electricity will become the renewable energy for Kentucky,as the generation of coal will but come to a stop within the near future.Like Denmark who is running on 100%renewable generation we must stride to become fully operational on solar.In the present work,we systematically studied about renewable energy resources,in particular,solar energy for the application of photovoltaic panels in Eastern Kentucky.By analyzing data from our PV cells at Morehead State University designed to follow the direction of the sun for optimized output and by incorporating MPPT charge controllers,we have constructed a maximum power algorithm that performs best for the location.Utilizing these,measurements of daily electricity production in comparison to the average power needed for household use has validated our research.With the advancements in solar cell technology what was once impossible is now reality,as solar power can easily power this region based on our data.Knowing this,being a prime location we can now push to enable the advancement of renewable energy production and become less dependent on fossil fuels,thus creating an infrastructure that will run off solar power.展开更多
Dropping probability of handoff calls and blocking probability of new calls are two important Quality of Service (QoS) measures for LTE-Advanced networks. Applying QoS for Cell edge users in soft frequency reuse schem...Dropping probability of handoff calls and blocking probability of new calls are two important Quality of Service (QoS) measures for LTE-Advanced networks. Applying QoS for Cell edge users in soft frequency reuse scheme in LTE system is a challenge as they already suffer from limited resources. Assigning some resources for handover calls may enhance dropping probability but this is in price of degradation in the blocking probability for new calls in cell-edge. Uniform Fractional Guard Channel (UFGC) is a call admission policy that provides QoS without reserving resources for handover calls. In this paper, the performance of Soft Frequency Reuse (SFR) in presence of Uniform Fractional Guard Channel (UFGC) will be investigated using queuing analysis. The mathematical model and performance metrics will be deduced in this assessment. The impact of UFGC will be evaluated in edge and core part separately. Then the optimal value for the parameter of UFGC will be obtained to minimize the blocking probability of new calls with the constraint on the upper bound on the dropping probability of handoff calls.展开更多
Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpra...Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpractices occur,large amounts of it retain in the water system causing increase rate in eutrophication and toxifies fish and aquaculture plants.Recent nitrate sensor prototypes still require performing the additional steps of water sample deionization and dilution and were constructed with expensive materials.In response to the challenge of sensor enhancement and aquaponic water quality monitoring,this study developed sensitive,repeatable,and reproducible screen-printed graphite electrodes on polyvinyl chloride and parchment paper substrates with silver as electrode material and 60:40 graphite powder:nail polish formulated conductive ink for electrical traces,integrated with 9-gene genetic expression model as a function of peak anodic current and electrochemical test time for nitrate concentration prediction that is embedded into low-power Arduino ESP32 for in situ nitrate sensing in aquaponic pond water.Five SPE electrical traces were designed on the two types of substrates.Scanning electron microscopy with energy dispersive X-ray confirmed the electrode surface morphology.Electrochemical cyclic voltammetry using 10 to 100 mg/L KNO3 and water from three-depth regions of the actual pond established the electrochemical test time(10.5 s)and electrode potential(0.135 V)protocol necessary to produce peak current that corresponds to the strength of nitrate ions during redox.The findings from in situ testing revealed that the proposed sensors have strong linear predictions(R2=0.968 MSE=1.659 for nSPEv and R2=0.966 MSE=4.697 for nSPEp)in the range of 10 to 100 mg/L and best detection limit of 3.15μg/L,which are comparable to other sensors of more complex construction.The developed three-electrode electrochemical nitrate sensor confirms that it is reliable for both biosensing in controlled solutions and in situ aquaponic pond water systems.展开更多
Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniqu...Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniques,especially deep learningmodels,developed to tackle these problems.This article first introduces the sensing systems employed for 2-D and 3-D road data acquisition,including camera(s),laser scanners and Microsoft Kinect.It then comprehensively reviews the SoTA computer vision algorithms,including(1)classical 2-D image processing,(2)3-D point cloud modelling and segmentation and(3)machine/deep learning,developed for road pothole detection.The article also discusses the existing challenges and future development trends of computer vision-based road pothole detection approaches:classical 2-D image processing-based and 3-D point cloud modelling and segmentation-based approaches have already become history;and convolutional neural networks(CNNs)have demonstrated compelling road pothole detection results and are promising to break the bottleneck with future advances in self/un-supervised learning for multi-modal semantic segmentation.We believe that this survey can serve as practical guidance for developing the next-generation road condition assessment systems.展开更多
Radiology（imaging） and imaging-guided interventions, which provide multi-parametric morphologic and functional information, are playing an increasingly significant role in precision medicine. Radiologists are traine...Radiology（imaging） and imaging-guided interventions, which provide multi-parametric morphologic and functional information, are playing an increasingly significant role in precision medicine. Radiologists are trained to understand the imaging phenotypes, transcribe those observations（phenotypes） to correlate with underlying diseases and to characterize the images. However, in order to understand and characterize the molecular phenotype（to obtain genomic information） of solid heterogeneous tumours, the advanced sequencing of those tissues using biopsy is required. Thus, radiologists image the tissues from various views and angles in order to have the complete image phenotypes, thereby acquiring a huge amount of data. Deriving meaningful details from all these radiological data becomes challenging and raises the big data issues. Therefore, interest in the application of radiomics has been growing in recent years as it has the potential to provide significant interpretive and predictive information for decision support. Radiomics is a combination of conventional computer-aided diagnosis, deep learning methods, and human skills, and thus can be used for quantitative characterization of tumour phenotypes. This paper discusses the overview of radiomics workflow, the results of various radiomics-based studies conducted using various radiological images such as computed tomography（CT）, magnetic resonance imaging（MRI）, and positron-emission tomography（PET）, the challenges we are facing, and the potential contribution of radiomics towards precision medicine.展开更多
Breast cancer is the second leading cause of death in women.It occurs when cells in the breast start to grow out of proportion and invade neighboring tissues or spread throughout the body.Mammography is one of the mos...Breast cancer is the second leading cause of death in women.It occurs when cells in the breast start to grow out of proportion and invade neighboring tissues or spread throughout the body.Mammography is one of the most effective and popular modalities presently used for breast cancer screening and detection.Efforts have been made to improve the accuracy of breast cancer diagnosis using different imaging modalities.Ultrasound and magnetic resonance imaging have been used to detect breast cancers in high risk patients.Recently,electrical impedance imaging and nuclear medicine techniques are also being widely used for breast cancer screening and diagnosis.In this paper,we discuss the capabilities of various breast imaging modalities.展开更多
A continuous surface potential versus voltage equation is proposed and then its solution is further discussed for a long channel intrinsic surrounding-gate（SRG） MOSFET from the accumulation to strong inversion regio...A continuous surface potential versus voltage equation is proposed and then its solution is further discussed for a long channel intrinsic surrounding-gate（SRG） MOSFET from the accumulation to strong inversion region.The original equation is derived from the exact solution of a simplified Poisson equation and then the empirical correction is performed from the mathematical condition required by the continuity of the solution,which results in a continuous surface potential versus voltage equation,allowing the surface potential and the related derivatives to be described by an analytic solution from the accumulation to strong inversion region and from linear to the saturation region accurately and continuously.From these results,the dependences of surface potential and centric potential characteristics on device geometry are analyzed and the results are also verified with the 3-D numerical simulation from the aspect of accuracy and continuity tests.展开更多
A robust digital receiver based on a matched filter （MF） is proposed for the radio frequency identification （RFID） reader system to enhance the reliability of signal processing in the electronic product code （EPC...A robust digital receiver based on a matched filter （MF） is proposed for the radio frequency identification （RFID） reader system to enhance the reliability of signal processing in the electronic product code （EPC） sensor network （ESN）. The performance of the proposed receiver is investigated by examining the anti-collision algorithm in the EPC global Class1 Generation2 protocol. The validity and usefulness are demonstrated by both computer simulations and experiments. Based on the verification results, comparing with the conventional zero crossing detector （ZCD） based receiver, the proposed receiver is very robust against strong amplitude distortions and considerable frequency deviations happening on the backscattered signal from a passive tag.展开更多
To measure the security for hot searched reversible data hiding(RDH)technique,especially for the common-used histogram-shifting based RDH(denoted as HS-RDH),several steganalysis schemes are designed to detect whether ...To measure the security for hot searched reversible data hiding(RDH)technique,especially for the common-used histogram-shifting based RDH(denoted as HS-RDH),several steganalysis schemes are designed to detect whether some secret data has been hidden in a normal-looking image.However,conventional steganalysis schemes focused on the previous RDH algorithms,i.e.,some early spatial/pixel domain-based histogram-shifting(HS)schemes,which might cause great changes in statistical characteristics and thus be easy to be detected.For recent improved methods,such as some adaptive prediction error(PE)based embedding schemes,those conventional schemes might be invalid,since those adaptive embedding mechanism would effectively reduce the embedding trace and thus increase the difficulty of steganalysis.Therefore,a novel steganalysis method is proposed in this paper to detect recent adaptive RDH schemes and provide a more effective detection tool for RDH.The contributions of this paper could be summarized as follows.(1)By analyzing the characteristics for those adaptive HS-RDH,an effective“flat ground”based detection method is designed to fast identify whether the given image is used to hide secret data;(2)According to the empirical statistical model,double check mechanism is provided to improve the detection accuracy;(3)In addition,to further improve detection ability,some detailed information for secret data,i.e.,its content and embedding location are further estimated.Compared with conventional steganalysis methods,experimental results indicate that our proposed algorithm could achieve a better detection accuracy and meanwhile acquire more detailed information on secret data.展开更多
This paper introduces a human gesture recognition algorithm using an impulse radio ultra-wide- band (IR-UWB) radar sensor. Human gesture recognition has been one of the hottest research topics for quite a long time. M...This paper introduces a human gesture recognition algorithm using an impulse radio ultra-wide- band (IR-UWB) radar sensor. Human gesture recognition has been one of the hottest research topics for quite a long time. Many gesture recognition algorithms or systems using other sensors have been proposed such as using cameras, RFID tags and so on. Among which gesture recognition systems using cameras have been extensively studied in past years and widely used in practical. While it might show some deficiencies in some cases. For example, the users might not like to be filmed by cameras considering their privacies. Besides, it might not work well in very dark environments. While RFID tags could be inconvenient to many people and are likely to be lost. Our gesture recognition algorithm uses IR-UWB radar sensor which has pretty high resolution in ranging and adjustable gesture recognition range, meanwhile, does not have problems in privacy issues or darkness. In this paper, the gesture recognition algorithm is based on the moving direction and distance change of the human hand and the change of the frontal surface area of hand towards radar sensor. By combining these changes while doing gestures, the algorithm may recognize basically 6 kinds of hand gestures. The experimental results show that these gestures are of quite good performance. The performance analysis from experiments is also given.展开更多
Estimating the crowd count and density of highly dense scenes witnessed in Muslim gatherings at religious sites in Makkah and Madinah is critical for developing control strategies and organizing such a large gathering...Estimating the crowd count and density of highly dense scenes witnessed in Muslim gatherings at religious sites in Makkah and Madinah is critical for developing control strategies and organizing such a large gathering.Moreover,since the crowd images in this case can range from low density to high density,detection-based approaches are hard to apply for crowd counting.Recently,deep learning-based regression has become the prominent approach for crowd counting problems,where a density-map is estimated,and its integral is further computed to acquire the final count result.In this paper,we put forward a novel multi-scale network(named 2U-Net)for crowd counting in sparse and dense scenarios.The proposed framework,which employs the U-Net architecture,is straightforward to implement,computationally efficient,and has single-step training.Unpooling layers are used to retrieve the pooling layers’erased information and learn hierarchically pixelwise spatial representation.This helps in obtaining feature values,retaining spatial locations,and maximizing data integrity to avoid data loss.In addition,a modified attention unit is introduced and integrated into the proposed 2UNet model to focus on specific crowd areas.The proposed model concentrates on balancing the number of model parameters,model size,computational cost,and counting accuracy compared with other works,which may involve acquiring one criterion at the expense of other constraints.Experiments on five challenging datasets for density estimation and crowd counting have shown that the proposed model is very effective and outperforms comparable mainstream models.Moreover,it counts very well in both sparse and congested crowd scenes.The 2U-Net model has the lowest MAE in both parts(Part A and Part B)of the ShanghaiTech,UCSD,and Mall benchmarks,with 63.3,7.4,1.5,and 1.6,respectively.Furthermore,it obtains the lowest MSE in the ShanghaiTech-Part B,UCSD,and Mall benchmarks with 12.0,1.9,and 2.1,respectively.展开更多
基金National Natural Science Foundation of China(10274026) Korea Science and Engineering Foundation of theQuantum-functional Semiconductor Research Center of Dongguk University
文摘Fabrication of GaAs/Si heterostructures and their photoelectric properties are investigated by Raman, photoluminescence and Hall-effect measurements. The crystallinity of GaAs epilayers grown on Si substrate is significantly affected by the substrate orientation and the growth method. The photoelectric properties of GaAs epilayers grown on Si (211) substrates deposited by using a two-step growth method are improved. These results indicate that GaAs epilayers grown on Si (100) and Si (211) substrates by using two-step growth method are promising for potential applications in high-speed and high-frequency photoelectric devices.
文摘The call admission control (CAC) optimizes the use of allocated channels against offered traffic maintaining the required quality of service (QoS). Provisioning QoS to user at cell-edge is a challenge where there is limitation in cell resources due to inter-cell interference (ICI). Soft Frequency Reuse is ICI mitigation scheme that controls the distribution of resources between users. In this paper, the Impact of four CAC schemes (Cutoff Priority scheme (CP), Uniform Fractional Guard Channel (UFGC), Limited Fractional Guard Channel (LFGC), New Call Bounding (NCB) scheme) at cell-edge have investigated using queuing analysis in a comparative manner. The comparison is based on two criteria. The first criterion guarantees a particular level of service to already admitted users while trying to optimize the revenue obtained. The second criterion determines the minimum of number of radio resources that provides hard constraints in both of blocking and dropping probabilities. The four schemes are compared at different scenarios of new and handover call arrival rates.
基金Project supported by the Ministry of Higher Education(MOHE)Malaysia under the Fundamental Research Grant Scheme(FRGS)(Grant No.Q.J130000.7823.4F477)
文摘The effect of tensile uniaxial strain on the non-parabolic electronic band structure of armchair graphene nanoribbon（AGNR） is investigated.In addition,the density of states and the carrier statistic based on the tight-binding Hamiltonian are modeled analytically.It is found that the property of AGNR in the non-parabolic band region is varied by the strain.The tunable energy band gap in AGNR upon strain at the minimum energy is described for each of n-AGNR families in the non-parabolic approximation.The behavior of AGNR in the presence of strain is attributed to the breakable AGNR electronic band structure,which varies the physical properties from its normality.The linear relation between the energy gap and the electrical properties is featured to further explain the characteristic of the deformed AGNR upon strain.
基金We would like to thanks to Ministry of Higher Education and UTeM through FRGS Grant F00430 FRGS/1/2020/FKEKK-CETRI/F00430 that support this research.
文摘In this paper,a high gain and directional coplanarwaveguide(CPW)-fed ultra-wideband(UWB)planar antenna with a new frequency selective surface(FSS)unit cells design is proposed for UWB applications.The proposed UWB antenna was designed based on the Mercedes artistic-shaped planar(MAP)antenna.The antenna consisted of a circular ring embedded with three straight legs for antenna impedance bandwidth improvement.The modelled FSS used the integration of a two parallel conductive metallic patch with a circular loop structure.The FSS provided a UWB stopband filter response covering a bandwidth of 10.5 GHz,for frequencies from 2.2 to 12.7 GHz.The proposed FSS had a compact physical dimension of 5 mm×5 mm×1.6 mm,with a printed array of 19×19 FSS unit cells.The FSS unit cells were printed on only one side of the dielectric FR4 substrate and placed as a sandwich between the antenna and the reflector ground plane.An equivalent circuit configuration(ECC)was used to verify the FSS unit cell structure’s performance.The simulated results indicated that the UWB MAP antenna and FSS reflector provided a fractional bandwidth of 136%and a high gain of 11.5 dB at 8.5 GHz with an acceptable radiation efficiency of 89%.Furthermore,the gain was improved across the operating band and kept between 8.3 and 11.5 dB.The proposed antenna was in good agreement between theoretical and experimental results and offered a wide enough bandwidth for UWB and vehicle applications.
基金Project supported by CERG Grant (615506) from the Research Grants Council of Hong Kong Special Administrative Region of China and Intel CorporationScience and Technology Plan of the Education Bureau of Guangxi Zhuang Autonomous Region of China (Grant No. 200911MS93)
文摘The fabrication and performance of 160-nm gate-length metamorphic AlInAs/GaInAs high electron mobility transistors （mHEMTs） grown on GaAs substrate by metal organic chemical vapour deposition （MOCVD） are reported. By using a novel combined optical and e-beam photolithography technology, submicron mHEMTs devices have been achieved. The devices exhibit good DC and RF performance. The maximum current density was 817 mA/mm and the maximum transconductance was 828 mS/mm. The non-alloyed Ohmic contact resistance Rc was as low as 0.02 Ω- ram. The unity current gain cut-off frequency （fT） and the maximum oscillation frequency （fmax） were 146 GHz and 189 GHz, respectively. This device has the highest fT yet reported for a 160-nm gate-length HEMTs grown by MOCVD. The output conductance is 28.9 mS/mm, which results in a large voltage gain of 28.6, Also, an input capacitance to gate-drain feedback capacitance ratio, Cgs/Cgd, of 4.3 is obtained in the device.
文摘The aim of this paper is to present DCM+, a new congestion control protocol for data networks. It stands for Dynamic Congestion control for Mobile networks. New metrics have been newly invented and introduced like normalized advancing index (NAI) and complete transmission time (CTT). The simulations are done for a simple single-hop-topology (sender-router-receiver). The outcomes of this protocol are excellent and, in most cases, better than other approaches. The excellent properties of our proposed protocol were possible through tracking the available slow-start threshold. We achieved performance improvement, minimized end-to-end delay and large reduction in transmission time. DCM+ was able to combine many advantages at same time of the protocols NewReno and Westwood+. The results show, that DCM+ is extremely adequate for different types of networks. Feedback as main principle of control theory was used to control the congestion in the network. The parameters Round-Trip-Time (RTT) and Retransmission Timeout (RTO) are used as feedback signals to adjust the next congestion window (cwnd).
基金This work was supported in part by the Geran Galakan Penyelidik Muda Grant(GGPM),Universiti Kebangsaan Malaysia,Selangor,Malaysia under grant GGPM-2021-055.
文摘This article presents an integrated current mode configurable analog block(CAB)system for field-programmable analog array(FPAA).The proposed architecture is based on the complementary metal-oxide semiconductor(CMOS)transistor level design where MOSFET transistors operating in the saturation region are adopted.The proposed CAB architecture is designed to implement six of thewidely used current mode operations in analog processing systems:addition,subtraction,integration,multiplication,division,and pass operation.The functionality of the proposed CAB is demonstrated through these six operations,where each operation is chosen based on the user’s selection in the CAB interface system.The architecture of the CAB system proposes an optimized way of designing and integrating only three functional cells with the interface circuitry to achieve the six operations.Furthermore,optimized programming and digital tuning circuitry are implemented in the architecture to control and interface with the functional cells.Moreover,these designed programming and tuning circuitries play an essential role in optimizing the performance of the proposed design.Simulation of the proposed CMOS Transistor Based CAB system is carried out using Tanner EDA Tools in 0.35μm standard CMOS technology.The design uses a±1.5 V power supply and results in maximum 3 dB bandwidth of 34.9 MHz and an approximate size of 0.0537 mm2.This demonstrates the advantages of the design over the current state-of-the-art designs presented for comparison in this article.Consequently,the proposed design has a clear aspect of simplicity,low power consumption,and high bandwidth operation,which makes it a suitable candidate for mobile telecommunications applications.
基金Supported by Fundamental Research Grant Scheme sanctioned by the Ministry of Education,Malaysia,No.FRGS/1/2019/SKK06/TAYLOR/02/3。
文摘BACKGROUND Liver cancer is the 6 th most common cancer in the world and the 4 th most common death from cancer worldwide.Hepatic radioembolization is a minimally invasive treatment involving intraarterial administration of radioembolic microspheres.AIM To develop a neutron-activated,biodegradable and theranostics samarium-153 acetylacetonate(153SmAcAc)-poly-L-lactic acid(PLLA)microsphere for intraarterial radioembolization of hepatic tumors.METHODS Microspheres with different concentrations of 152SmAcAc(i.e.,100%,150%,175%and 200%w/w)were prepared by solvent evaporation method.The microspheres were then activated using a nuclear reactor in a neutron flux of 2×10^12n/cm^2/s^1,converting 152Sm to Samarium-153(153)Sm)via 152Sm(n,γ) 153Sm reaction.The SmAcAc-PLLA microspheres before and after neutron activation were characterized using scanning electron microscope,energy dispersive X-ray spectroscopy,particle size analysis,Fourier transform infrared spectroscopy,thermo-gravimetric analysis and gamma spectroscopy.The in-vitro radiolabeling efficiency was also tested in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.RESULTS The SmAcAc-PLLA microspheres with different SmAcAc contents remained spherical before and after neutron activation.The mean diameter of the microspheres was about 35μm.Specific activity achieved for 153SmAcAc-PLLA microspheres with 100%,150%,175%and 200%(w/w)SmAcAc after 3 h neutron activation were 1.7±0.05,2.5±0.05,2.7±0.07,and 2.8±0.09 GBq/g,respectively.The activity of per microspheres were determined as 48.36±1.33,74.10±1.65,97.87±2.48,and 109.83±3.71 Bq for 153SmAcAc-PLLA microspheres with 100%,150%,175%and 200%(w/w)SmAcAc.The energy dispersive X-ray and gamma spectrometry showed that no elemental and radioactive impurities present in the microspheres after neutron activation.Retention efficiency of 153Sm in the SmAcAc-PLLA microspheres was excellent(approximately 99%)in both 0.9%sodium chloride solution and human blood plasma over a duration of 550 h.CONCLUSION The 153SmAcAc-PLLA microsphere is potentially useful for hepatic radioembolization due to their biodegradability,favorable physicochemical characteristics and excellent radiolabeling efficiency.The synthesis of the formulation does not involve ionizing radiation and hence reducing the complication and cost of production.
文摘We propose a novel resonator that can reduce magnetic field leakage using a ferrite plate. The proposed resonator consists of a rectangular loop, a ferrite plate, and an L-matching network. The ferrite plate is used as an H-field reflector to direct more H-field to each resonator, and the L-matching network is employed to match the 50 Ω of the feed cable at 13.56 MHz. Two identical resonators with dimensions of 30 cm × 15 cm are separated by 50 cm, and the resulting transmission efficiency is about ?12.3 dB at 13.56 MHz. This is about 4.2 dB higher than the resonators without the ferrite plate.
文摘Photovoltaics(PV-also called solar photovoltaic devices)are used to harness the power of the sun via the electronic process that occurs within semiconductor cells.The solar energy is absorbed by the cells,which causes the electrons to break away from their atoms,allowing them to flow within the material to produce electricity.This electricity will become the renewable energy for Kentucky,as the generation of coal will but come to a stop within the near future.Like Denmark who is running on 100%renewable generation we must stride to become fully operational on solar.In the present work,we systematically studied about renewable energy resources,in particular,solar energy for the application of photovoltaic panels in Eastern Kentucky.By analyzing data from our PV cells at Morehead State University designed to follow the direction of the sun for optimized output and by incorporating MPPT charge controllers,we have constructed a maximum power algorithm that performs best for the location.Utilizing these,measurements of daily electricity production in comparison to the average power needed for household use has validated our research.With the advancements in solar cell technology what was once impossible is now reality,as solar power can easily power this region based on our data.Knowing this,being a prime location we can now push to enable the advancement of renewable energy production and become less dependent on fossil fuels,thus creating an infrastructure that will run off solar power.
文摘Dropping probability of handoff calls and blocking probability of new calls are two important Quality of Service (QoS) measures for LTE-Advanced networks. Applying QoS for Cell edge users in soft frequency reuse scheme in LTE system is a challenge as they already suffer from limited resources. Assigning some resources for handover calls may enhance dropping probability but this is in price of degradation in the blocking probability for new calls in cell-edge. Uniform Fractional Guard Channel (UFGC) is a call admission policy that provides QoS without reserving resources for handover calls. In this paper, the performance of Soft Frequency Reuse (SFR) in presence of Uniform Fractional Guard Channel (UFGC) will be investigated using queuing analysis. The mathematical model and performance metrics will be deduced in this assessment. The impact of UFGC will be evaluated in edge and core part separately. Then the optimal value for the parameter of UFGC will be obtained to minimize the blocking probability of new calls with the constraint on the upper bound on the dropping probability of handoff calls.
基金the Philippines’Department of Science and Technology-Engineering Research and Development for Technology program,the Intelligent Systems Laboratory and the iNano Laboratory of the De La Salle University,the Fundação para a Ciência e a Tecnologia(FCT)for funding MARE(Marine and Environmental Sciences Centre,UIDB/04292/2020 and UIDB/04292/2020)ARNET(Aquatic Research Infrastructure Network Associated Laboratory,LA/P/0069/2020)B.Duarte researcher contract(CEECIND/00511/2017).
文摘Nitrate is the primary water-soluble macronutrient essential for plant growth that is converted from excess fish feeds,fish effluents,and degrading biomaterials on the aquaponic pond floor,and when aquacultural malpractices occur,large amounts of it retain in the water system causing increase rate in eutrophication and toxifies fish and aquaculture plants.Recent nitrate sensor prototypes still require performing the additional steps of water sample deionization and dilution and were constructed with expensive materials.In response to the challenge of sensor enhancement and aquaponic water quality monitoring,this study developed sensitive,repeatable,and reproducible screen-printed graphite electrodes on polyvinyl chloride and parchment paper substrates with silver as electrode material and 60:40 graphite powder:nail polish formulated conductive ink for electrical traces,integrated with 9-gene genetic expression model as a function of peak anodic current and electrochemical test time for nitrate concentration prediction that is embedded into low-power Arduino ESP32 for in situ nitrate sensing in aquaponic pond water.Five SPE electrical traces were designed on the two types of substrates.Scanning electron microscopy with energy dispersive X-ray confirmed the electrode surface morphology.Electrochemical cyclic voltammetry using 10 to 100 mg/L KNO3 and water from three-depth regions of the actual pond established the electrochemical test time(10.5 s)and electrode potential(0.135 V)protocol necessary to produce peak current that corresponds to the strength of nitrate ions during redox.The findings from in situ testing revealed that the proposed sensors have strong linear predictions(R2=0.968 MSE=1.659 for nSPEv and R2=0.966 MSE=4.697 for nSPEp)in the range of 10 to 100 mg/L and best detection limit of 3.15μg/L,which are comparable to other sensors of more complex construction.The developed three-electrode electrochemical nitrate sensor confirms that it is reliable for both biosensing in controlled solutions and in situ aquaponic pond water systems.
基金the National Key R&D Program of China(Grant No.2020AAA0108100)the Fundamental Research Funds for the Central Universities(Grant Nos.22120220184,22120220214 and 2022-5-YB-08)the Shanghai Municipal Science and Technology Major Project(Grant No.2021SHZDZX0100).
文摘Computer vision algorithms have been utilized for 3-D road imaging and pothole detection for over two decades.Nonetheless,there is a lack of systematic survey articles on state-of-the-art(SoTA)computer vision techniques,especially deep learningmodels,developed to tackle these problems.This article first introduces the sensing systems employed for 2-D and 3-D road data acquisition,including camera(s),laser scanners and Microsoft Kinect.It then comprehensively reviews the SoTA computer vision algorithms,including(1)classical 2-D image processing,(2)3-D point cloud modelling and segmentation and(3)machine/deep learning,developed for road pothole detection.The article also discusses the existing challenges and future development trends of computer vision-based road pothole detection approaches:classical 2-D image processing-based and 3-D point cloud modelling and segmentation-based approaches have already become history;and convolutional neural networks(CNNs)have demonstrated compelling road pothole detection results and are promising to break the bottleneck with future advances in self/un-supervised learning for multi-modal semantic segmentation.We believe that this survey can serve as practical guidance for developing the next-generation road condition assessment systems.
文摘Radiology（imaging） and imaging-guided interventions, which provide multi-parametric morphologic and functional information, are playing an increasingly significant role in precision medicine. Radiologists are trained to understand the imaging phenotypes, transcribe those observations（phenotypes） to correlate with underlying diseases and to characterize the images. However, in order to understand and characterize the molecular phenotype（to obtain genomic information） of solid heterogeneous tumours, the advanced sequencing of those tissues using biopsy is required. Thus, radiologists image the tissues from various views and angles in order to have the complete image phenotypes, thereby acquiring a huge amount of data. Deriving meaningful details from all these radiological data becomes challenging and raises the big data issues. Therefore, interest in the application of radiomics has been growing in recent years as it has the potential to provide significant interpretive and predictive information for decision support. Radiomics is a combination of conventional computer-aided diagnosis, deep learning methods, and human skills, and thus can be used for quantitative characterization of tumour phenotypes. This paper discusses the overview of radiomics workflow, the results of various radiomics-based studies conducted using various radiological images such as computed tomography（CT）, magnetic resonance imaging（MRI）, and positron-emission tomography（PET）, the challenges we are facing, and the potential contribution of radiomics towards precision medicine.
文摘Breast cancer is the second leading cause of death in women.It occurs when cells in the breast start to grow out of proportion and invade neighboring tissues or spread throughout the body.Mammography is one of the most effective and popular modalities presently used for breast cancer screening and detection.Efforts have been made to improve the accuracy of breast cancer diagnosis using different imaging modalities.Ultrasound and magnetic resonance imaging have been used to detect breast cancers in high risk patients.Recently,electrical impedance imaging and nuclear medicine techniques are also being widely used for breast cancer screening and diagnosis.In this paper,we discuss the capabilities of various breast imaging modalities.
基金Project supported by the National Natural Science Foundation of China(No.60876027)the Competitive Earmarked Program from the Research Grant Council of Hong Kong SAR,China(No.HKUST6289/04E)+1 种基金the Industry,Education and Academy Cooperation Program of Guangdong Province,China(No.2009B090300318)the Fundamental Research Project of Shenzhen Science & Technology Foundation,China(No.JC200903160353A).
文摘A continuous surface potential versus voltage equation is proposed and then its solution is further discussed for a long channel intrinsic surrounding-gate（SRG） MOSFET from the accumulation to strong inversion region.The original equation is derived from the exact solution of a simplified Poisson equation and then the empirical correction is performed from the mathematical condition required by the continuity of the solution,which results in a continuous surface potential versus voltage equation,allowing the surface potential and the related derivatives to be described by an analytic solution from the accumulation to strong inversion region and from linear to the saturation region accurately and continuously.From these results,the dependences of surface potential and centric potential characteristics on device geometry are analyzed and the results are also verified with the 3-D numerical simulation from the aspect of accuracy and continuity tests.
基金supported by the Korea Evaluation Institute of Industrial Technology(KEIT),under the R&D Support Program of Ministry of Knowledge Economy,Korea
文摘A robust digital receiver based on a matched filter （MF） is proposed for the radio frequency identification （RFID） reader system to enhance the reliability of signal processing in the electronic product code （EPC） sensor network （ESN）. The performance of the proposed receiver is investigated by examining the anti-collision algorithm in the EPC global Class1 Generation2 protocol. The validity and usefulness are demonstrated by both computer simulations and experiments. Based on the verification results, comparing with the conventional zero crossing detector （ZCD） based receiver, the proposed receiver is very robust against strong amplitude distortions and considerable frequency deviations happening on the backscattered signal from a passive tag.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 61762054,U1736215,61772573 and 61563022in part by the National Science Foundation for Distinguished Young Scholars of Jiangxi Province under Grant 20171BCB23072Many thanks to the anonymous reviewers for their insightful comments and valuable suggestions,which helped a lot to improve the paper quality.
文摘To measure the security for hot searched reversible data hiding(RDH)technique,especially for the common-used histogram-shifting based RDH(denoted as HS-RDH),several steganalysis schemes are designed to detect whether some secret data has been hidden in a normal-looking image.However,conventional steganalysis schemes focused on the previous RDH algorithms,i.e.,some early spatial/pixel domain-based histogram-shifting(HS)schemes,which might cause great changes in statistical characteristics and thus be easy to be detected.For recent improved methods,such as some adaptive prediction error(PE)based embedding schemes,those conventional schemes might be invalid,since those adaptive embedding mechanism would effectively reduce the embedding trace and thus increase the difficulty of steganalysis.Therefore,a novel steganalysis method is proposed in this paper to detect recent adaptive RDH schemes and provide a more effective detection tool for RDH.The contributions of this paper could be summarized as follows.(1)By analyzing the characteristics for those adaptive HS-RDH,an effective“flat ground”based detection method is designed to fast identify whether the given image is used to hide secret data;(2)According to the empirical statistical model,double check mechanism is provided to improve the detection accuracy;(3)In addition,to further improve detection ability,some detailed information for secret data,i.e.,its content and embedding location are further estimated.Compared with conventional steganalysis methods,experimental results indicate that our proposed algorithm could achieve a better detection accuracy and meanwhile acquire more detailed information on secret data.
文摘This paper introduces a human gesture recognition algorithm using an impulse radio ultra-wide- band (IR-UWB) radar sensor. Human gesture recognition has been one of the hottest research topics for quite a long time. Many gesture recognition algorithms or systems using other sensors have been proposed such as using cameras, RFID tags and so on. Among which gesture recognition systems using cameras have been extensively studied in past years and widely used in practical. While it might show some deficiencies in some cases. For example, the users might not like to be filmed by cameras considering their privacies. Besides, it might not work well in very dark environments. While RFID tags could be inconvenient to many people and are likely to be lost. Our gesture recognition algorithm uses IR-UWB radar sensor which has pretty high resolution in ranging and adjustable gesture recognition range, meanwhile, does not have problems in privacy issues or darkness. In this paper, the gesture recognition algorithm is based on the moving direction and distance change of the human hand and the change of the frontal surface area of hand towards radar sensor. By combining these changes while doing gestures, the algorithm may recognize basically 6 kinds of hand gestures. The experimental results show that these gestures are of quite good performance. The performance analysis from experiments is also given.
基金This research work is supported by the Deputyship of Research&Innovation,Ministry of Education in Saudi Arabia(Grant Number 758).
文摘Estimating the crowd count and density of highly dense scenes witnessed in Muslim gatherings at religious sites in Makkah and Madinah is critical for developing control strategies and organizing such a large gathering.Moreover,since the crowd images in this case can range from low density to high density,detection-based approaches are hard to apply for crowd counting.Recently,deep learning-based regression has become the prominent approach for crowd counting problems,where a density-map is estimated,and its integral is further computed to acquire the final count result.In this paper,we put forward a novel multi-scale network(named 2U-Net)for crowd counting in sparse and dense scenarios.The proposed framework,which employs the U-Net architecture,is straightforward to implement,computationally efficient,and has single-step training.Unpooling layers are used to retrieve the pooling layers’erased information and learn hierarchically pixelwise spatial representation.This helps in obtaining feature values,retaining spatial locations,and maximizing data integrity to avoid data loss.In addition,a modified attention unit is introduced and integrated into the proposed 2UNet model to focus on specific crowd areas.The proposed model concentrates on balancing the number of model parameters,model size,computational cost,and counting accuracy compared with other works,which may involve acquiring one criterion at the expense of other constraints.Experiments on five challenging datasets for density estimation and crowd counting have shown that the proposed model is very effective and outperforms comparable mainstream models.Moreover,it counts very well in both sparse and congested crowd scenes.The 2U-Net model has the lowest MAE in both parts(Part A and Part B)of the ShanghaiTech,UCSD,and Mall benchmarks,with 63.3,7.4,1.5,and 1.6,respectively.Furthermore,it obtains the lowest MSE in the ShanghaiTech-Part B,UCSD,and Mall benchmarks with 12.0,1.9,and 2.1,respectively.
