Quantum key distribution(QKD),rooted in quantum mechanics,offers information-theoretic security.However,practi-cal systems open security threats due to imperfections,notably bright-light blinding attacks targeting sin...Quantum key distribution(QKD),rooted in quantum mechanics,offers information-theoretic security.However,practi-cal systems open security threats due to imperfections,notably bright-light blinding attacks targeting single-photon detectors.Here,we propose a concise,robust defense strategy for protecting single-photon detectors in QKD systems against blinding attacks.Our strategy uses a dual approach:detecting the bias current of the avalanche photodiode(APD)to defend against con-tinuous-wave blinding attacks,and monitoring the avalanche amplitude to protect against pulsed blinding attacks.By integrat-ing these two branches,the proposed solution effectively identifies and mitigates a wide range of bright light injection attempts,significantly enhancing the resilience of QKD systems against various bright-light blinding attacks.This method forti-fies the safeguards of quantum communications and offers a crucial contribution to the field of quantum information security.展开更多
For the goals of security and privacy preservation,we propose a blind batch encryption-and public ledger-based data sharing protocol that allows the integrity of sensitive data to be audited by a public ledger and all...For the goals of security and privacy preservation,we propose a blind batch encryption-and public ledger-based data sharing protocol that allows the integrity of sensitive data to be audited by a public ledger and allows privacy information to be preserved.Data owners can tightly manage their data with efficient revocation and only grant one-time adaptive access for the fulfillment of the requester.We prove that our protocol is semanticallly secure,blind,and secure against oblivious requesters and malicious file keepers.We also provide security analysis in the context of four typical attacks.展开更多
In LEO satellite communication networks,the number of satellites has increased sharply, the relative velocity of satellites is very fast, then electronic signal aliasing occurs from time to time. Those aliasing signal...In LEO satellite communication networks,the number of satellites has increased sharply, the relative velocity of satellites is very fast, then electronic signal aliasing occurs from time to time. Those aliasing signals make the receiving ability of the signal receiver worse, the signal processing ability weaker,and the anti-interference ability of the communication system lower. Aiming at the above problems, to save communication resources and improve communication efficiency, and considering the irregularity of interference signals, the underdetermined blind separation technology can effectively deal with the problem of interference sensing and signal reconstruction in this scenario. In order to improve the stability of source signal separation and the security of information transmission, a greedy optimization algorithm can be executed. At the same time, to improve network information transmission efficiency and prevent algorithms from getting trapped in local optima, delete low-energy points during each iteration process. Ultimately, simulation experiments validate that the algorithm presented in this paper enhances both the transmission efficiency of the network transmission system and the security of the communication system, achieving the process of interference sensing and signal reconstruction in the LEO satellite communication system.展开更多
In the field of single-server blind quantum computation(BQC), a major focus is to make the client as classical as possible. To achieve this goal, we propose two single-server BQC protocols to achieve verifiable univer...In the field of single-server blind quantum computation(BQC), a major focus is to make the client as classical as possible. To achieve this goal, we propose two single-server BQC protocols to achieve verifiable universal quantum computation. In these two protocols, the client only needs to perform either the gate T(in the first protocol) or the gates H and X(in the second protocol). With assistance from a single server, the client can utilize his quantum capabilities to generate some single-qubit states while keeping the actual state of these qubits confidential from others. By using these single-qubit states, the verifiable universal quantum computation can be achieved.展开更多
People’s lives have become easier and simpler as technology has proliferated.This is especially true with the Internet of Things(IoT).The biggest problem for blind people is figuring out how to get where they want to...People’s lives have become easier and simpler as technology has proliferated.This is especially true with the Internet of Things(IoT).The biggest problem for blind people is figuring out how to get where they want to go.People with good eyesight need to help these people.Smart shoes are a technique that helps blind people find their way when they walk.So,a special shoe has been made to help blind people walk safely without worrying about running into other people or solid objects.In this research,we are making a new safety system and a smart shoe for blind people.The system is based on Internet of Things(IoT)technology and uses three ultrasonic sensors to allow users to hear and react to barriers.It has ultrasonic sensors and a microprocessor that can tell how far away something is and if there are any obstacles.Water and flame sensors were used,and a sound was used to let the person know if an obstacle was near him.The sensors use Global Positioning System(GPS)technology to detect motion from almost every side to keep an eye on them and ensure they are safe.To test our proposal,we gave a questionnaire to 100 people.The questionnaire has eleven questions,and 99.1%of the people who filled it out said that the product meets their needs.展开更多
Previous deep learning-based super-resolution(SR)methods rely on the assumption that the degradation process is predefined(e.g.,bicubic downsampling).Thus,their performance would suffer from deterioration if the real ...Previous deep learning-based super-resolution(SR)methods rely on the assumption that the degradation process is predefined(e.g.,bicubic downsampling).Thus,their performance would suffer from deterioration if the real degradation is not consistent with the assumption.To deal with real-world scenarios,existing blind SR methods are committed to estimating both the degradation and the super-resolved image with an extra loss or iterative scheme.However,degradation estimation that requires more computation would result in limited SR performance due to the accumulated estimation errors.In this paper,we propose a contrastive regularization built upon contrastive learning to exploit both the information of blurry images and clear images as negative and positive samples,respectively.Contrastive regularization ensures that the restored image is pulled closer to the clear image and pushed far away from the blurry image in the representation space.Furthermore,instead of estimating the degradation,we extract global statistical prior information to capture the character of the distortion.Considering the coupling between the degradation and the low-resolution image,we embed the global prior into the distortion-specific SR network to make our method adaptive to the changes of distortions.We term our distortion-specific network with contrastive regularization as CRDNet.The extensive experiments on synthetic and realworld scenes demonstrate that our lightweight CRDNet surpasses state-of-the-art blind super-resolution approaches.展开更多
Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better cr...Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better crystal quality,which is verified from x-ray diffraction(XRD)and scanning electron microscope(SEM)results.The Ga_(2)O_(3)-based solar blind photodetectors with different thicknesses are fabricated and studied.The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness.The photodetectors with inter-fingered structure based on 900 growth cyclesβ-Ga_(2)O_(3)active layers(corresponding film thickness of 58 nm)exhibit the best performances including a low dark current of 134 fA,photo-to-dark current ratio of 1.5×10^(7),photoresponsivity of 1.56 A/W,detectivity of 2.77×10^(14)Jones,and external quantum efficiency of 764.49%at a bias voltage of 10 V under 254-nm DUV illumination.The photoresponse rejection ratio(R_(254)/R_(365))is up to 1.86×10^(5).In addition,we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure.As the finger spacing decreases from 50μm to10μW,the photoresponsivity,detectivity,and external quantum efficiency increase significantly.展开更多
Objective:Preventive measures and appropriate rehabilitation are important in reducing the social burden of blindness.This study was to evaluate the etiologies,proportions,and level of rehabilitation for patients with...Objective:Preventive measures and appropriate rehabilitation are important in reducing the social burden of blindness.This study was to evaluate the etiologies,proportions,and level of rehabilitation for patients with blindness.Materials and Methods:A prospective observational study with 1000 visually impaired patients was conducted.The data regarding age,gender,socioeconomic status(SES),etiologies,curable or incurable blindness(IB),treatments,awareness,and state of rehabilitation were collected and reviewed.Results:The ratio of curable to IB was 0.82:1.The proportion of blindness rises after 40,even while the proportion of curable blindness(CB)increases after 60.The male–female ratios were 1.25:1 and 1:1.66 in the cases of CB and IB,respectively.On the other hand,the male–female ratio for childhood blindness was 1.66:1.Cataracts(78.22%)were the most common cause of CB,whereas diabetic retinopathy(24%),corneal opacity(17.5%),and trauma(12.4%)were causes of IB.Patients with illiteracy,low SES,and female gender were more likely to develop IB.There were low enrollment rates at the blind school and poor rehabilitation,mainly because of a lack of knowledge.Conclusion:Diabetic retinopathy,corneal opacity,and trauma are the major causes of IB.IB and poor rehabilitation were more profound in women and were associated with illiteracy,low SES,and a lack of awareness.展开更多
Visuality can be generically described as the quality of the visual,that is,as the given visual field in which a subject’s attention is concentrated.In fact,the visual is intrinsically linked to human vision,and this...Visuality can be generically described as the quality of the visual,that is,as the given visual field in which a subject’s attention is concentrated.In fact,the visual is intrinsically linked to human vision,and this presupposes the existence of a visible horizon from which(visual)images are given.However,this formulation presents something uncanny paradoxical because it forgets,on one hand,the broader status of the image(such as auditory and olfactory images)-seeing is not just a visual process(at least since Diderot we know it)and there are mental mechanisms in the visual constitution process that help to fabricate reality and that gestalt theory has explained-and on the other hand,the possibility of seeing beyond what is visible,after all,everything(or almost everything)that presents itself in a digital and virtual environment it can be quite ontologically suspect.Based on some of these premises,we will trace a path of analysis that leads us to the current blindness:unconditional faith in digital technology and the fragile hope of happiness in a way that rejects the reality of the visible.展开更多
He carefully pulled open the unlocked,light grey security door and saw an outdated,pale yellow plywood door.He was thrilled.His previous experience in lockpicking helped him effortlessly enter this shabby apartment.Ru...He carefully pulled open the unlocked,light grey security door and saw an outdated,pale yellow plywood door.He was thrilled.His previous experience in lockpicking helped him effortlessly enter this shabby apartment.Rumour had it that such kind of apartments might contain secret treasure of corrupt officials.He inserted his tools into the keyhole,and the door clicked open.This simple lock was too easy for him to open with his professional skills.He could not help thinking the host was a fool.展开更多
AIM:To estimate the prevalence of blindness and visual impairment resulting from cataract in the population aged≥50 y in Hungary,and to assess the cataract surgical services.METHODS:A rapid assessment of avoidable bl...AIM:To estimate the prevalence of blindness and visual impairment resulting from cataract in the population aged≥50 y in Hungary,and to assess the cataract surgical services.METHODS:A rapid assessment of avoidable blindness(RAAB)was conducted.A total of 3523 eligible people were randomly selected and examined.Each participant underwent surgery for cataract was interviewed with regard to the year,place,and costs of the surgery.Participants with obvious cataract were asked why they had not yet undergone surgery(barriers to surgery).RESULTS:An estimated 12514 people were bilaterally blind;the visual acuity(VA)in 19293 people was<6/60,and the VA in 73962 people was<6/18 in the better eye due to cataract.An estimated 77933 eyes are blind;98067 eyes had a VA of<6/60,and an estimated 277493 eyes had a VA of<6/18 due to cataract.Almost all cataract surgeries were conducted in government hospitals.The age-and sexadjusted cataract surgical coverage with VA<3/60 in eyes was 90.0%.The rate of good visual outcome after surgery was 79.5%.Ocular comorbidity was the main cause of poor outcome(78.1%),followed by late complications(such as posterior capsule opacification)(17.2%),inadequate optical correction(3.1%),and surgical complications(1.6%).The main barrier to surgery in people with bilateral cataract and VA of<6/60 was‘need not felt’.CONCLUSION:The prevalence of visual impairment resulting from cataract is slightly higher than expected.The quality of the cataract surgical service seems adequate in Hungary.However,the number of cataract operations per year should continue to increase due to the increasing patient demands and the aging population.展开更多
As an ill-posed problem, multiframe blind super resolution imaging recovers a high resolution image from a group of low resolution images with some degradations when the information of blur kernel is limited. Note tha...As an ill-posed problem, multiframe blind super resolution imaging recovers a high resolution image from a group of low resolution images with some degradations when the information of blur kernel is limited. Note that the quality of the recovered image is influenced more by the accuracy of blur estimation than an advanced regularization. We study the traditional model of the multiframe super resolution and modify it for blind deblurring. Based on the analysis, we proposed two algorithms. The first one is based on the total variation blind deconvolution algorithm and formulated as a functional for optimization with the regularization of blur. Based on the alternating minimization and the gradient descent algorithm, the high resolution image and the unknown blur kernel are estimated iteratively. By using the median shift and add operator, the second algorithm is more robust to the outlier influence. The MSAA initialization simplifies the interpolation process to reconstruct the blurred high resolution image for blind deblurring and improves the accuracy of blind super resolution imaging. The experimental results demonstrate the superiority and accuracy of our novel algorithms.展开更多
Speech recognition rate will deteriorate greatly in human-machine interaction when the speaker's speech mixes with a bystander's voice. This paper proposes a time-frequency approach for Blind Source Seperation...Speech recognition rate will deteriorate greatly in human-machine interaction when the speaker's speech mixes with a bystander's voice. This paper proposes a time-frequency approach for Blind Source Seperation (BSS) for intelligent Human-Machine Interaction(HMI). Main idea of the algorithm is to simultaneously diagonalize the correlation matrix of the pre-whitened signals at different time delays for every frequency bins in time-frequency domain. The prososed method has two merits: (1) fast convergence speed; (2) high signal to interference ratio of the separated signals. Numerical evaluations are used to compare the performance of the proposed algorithm with two other deconvolution algorithms. An efficient algorithm to resolve permutation ambiguity is also proposed in this paper. The algorithm proposed saves more than 10% of computational time with properly selected parameters and achieves good performances for both simulated convolutive mixtures and real room recorded speeches.展开更多
In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algo...In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algorithms and outputs of the quantum computation are confidential to the server.Verifiability refers to the ability of the client to verify with a certain probability whether the server has executed the protocol correctly and can be realized by introducing trap qubits into the computation graph state to detect server deception.The existing verifiable universal BQC protocols are analyzed and compared in detail.The XTH protocol(proposed by Xu Q S,Tan X Q,Huang R in 2020),a recent improvement protocol of verifiable universal BQC,uses a sandglass-like graph state to further decrease resource expenditure and enhance verification capability.However,the XTH protocol has two shortcomings:limitations in the coloring scheme and a high probability of accepting an incorrect computation result.In this paper,we present an improved version of the XTH protocol,which revises the limitations of the original coloring scheme and further improves the verification ability.The analysis demonstrates that the resource expenditure is the same as for the XTH protocol,while the probability of accepting the wrong computation result is reduced from the original minimum(0.866)^(d*)to(0.819)^(d^(*)),where d;is the number of repeated executions of the protocol.展开更多
In this paper a closed-form approximated expression is proposed for the Intersymbol Interference (ISI) as a function of time valid during the entire stages of the non-blind adaptive deconvolution process and is suitab...In this paper a closed-form approximated expression is proposed for the Intersymbol Interference (ISI) as a function of time valid during the entire stages of the non-blind adaptive deconvolution process and is suitable for the noisy, real and two independent quadrature carrier input case. The obtained expression is applicable for type of channels where the resulting ISI as a function of time can be described with an exponential model having a single time constant. Based on this new expression for the ISI as a function of time, the convergence time (or number of iteration number required for convergence) of the non-blind adaptive equalizer can be calculated. Up to now, the equalizer’s performance (convergence time and ISI as a function of time) could be obtained only via simulation when the channel coefficients were known. The new proposed expression for the ISI as a function of time is based on the knowledge of the initial ISI and channel power (which is measurable) and eliminates the need to carry out any more the above mentioned simulation. Simulation results indicate a high correlation between the simulated and calculated ISI (based on our proposed expression for the ISI as a function of time) during the whole deconvolution process for the high as well as for the low signal to noise ratio (SNR) condition.展开更多
AIM: To determine the prevalence and risk factors for eye diseases, blindness, and low vision in Tibet, and to assist the development of eye disease prevention and treatment schemes.METHODS: We carried out a survey of...AIM: To determine the prevalence and risk factors for eye diseases, blindness, and low vision in Tibet, and to assist the development of eye disease prevention and treatment schemes.METHODS: We carried out a survey of eye diseases among a population living at high altitude. A total of 1 115 Tibetan permanent residents aged 40 years or older from the towns and villages of Qushui County, Lhasa Prefecture, Tibet Autonomous Region, participated in this study. All participants completed a detailed questio-nnaire, and underwent presenting and pinhole visual acuity tests,and a comprehensive ophthalmic examination.RESULTS: There were 187 blind eyes (8.43%), 231 eyes with low vision (10.41% ). The leading cause of visual impairment was cataract of 55.0% (101/187) blindness and of 50.2% (116/231) low vision, followed by fundus lesions of 22.9% blindness and 23.8% low vision, while only a low prevalence of glaucoma of 9.6% blindness and 1.7% low vision was observed. The analysis of 2 219 eyes showed that the most common external eye disease was pterygium (27.2%) in Tibet.CONCLUSION: The high prevalence of blindness and low vision in the Tibetan population at high altitude is a serious public health issue. There is a need to establish and maintain an appropriate effective eye care program in Tibet.展开更多
Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context.This paper is dedicated to the blind identification of rate k/n convolutional encoders in a nois...Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context.This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noisy context based on Walsh-Hadamard transformation and block matrix(WHT-BM). The proposed algorithm constructs a system of noisy linear equations and utilizes all its coefficients to recover parity check matrix. It is able to make use of fault-tolerant feature of WHT, thus providing more accurate results and achieving better error performance in high raw bit error rate(BER) regions. Moreover, it is more computationally efficient with the use of the block matrix(BM) method.展开更多
基金This work was supported by the Major Scientific and Technological Special Project of Anhui Province(202103a13010004)the Major Scientific and Technological Special Project of Hefei City(2021DX007)+1 种基金the Key R&D Plan of Shandong Province(2020CXGC010105)the China Postdoctoral Science Foundation(2021M700315).
文摘Quantum key distribution(QKD),rooted in quantum mechanics,offers information-theoretic security.However,practi-cal systems open security threats due to imperfections,notably bright-light blinding attacks targeting single-photon detectors.Here,we propose a concise,robust defense strategy for protecting single-photon detectors in QKD systems against blinding attacks.Our strategy uses a dual approach:detecting the bias current of the avalanche photodiode(APD)to defend against con-tinuous-wave blinding attacks,and monitoring the avalanche amplitude to protect against pulsed blinding attacks.By integrat-ing these two branches,the proposed solution effectively identifies and mitigates a wide range of bright light injection attempts,significantly enhancing the resilience of QKD systems against various bright-light blinding attacks.This method forti-fies the safeguards of quantum communications and offers a crucial contribution to the field of quantum information security.
基金partially supported by the National Natural Science Foundation of China under grant no.62372245the Foundation of Yunnan Key Laboratory of Blockchain Application Technology under Grant 202105AG070005+1 种基金in part by the Foundation of State Key Laboratory of Public Big Datain part by the Foundation of Key Laboratory of Computational Science and Application of Hainan Province under Grant JSKX202202。
文摘For the goals of security and privacy preservation,we propose a blind batch encryption-and public ledger-based data sharing protocol that allows the integrity of sensitive data to be audited by a public ledger and allows privacy information to be preserved.Data owners can tightly manage their data with efficient revocation and only grant one-time adaptive access for the fulfillment of the requester.We prove that our protocol is semanticallly secure,blind,and secure against oblivious requesters and malicious file keepers.We also provide security analysis in the context of four typical attacks.
基金supported by National Natural Science Foundation of China (62171390)Central Universities of Southwest Minzu University (ZYN2022032,2023NYXXS034)the State Scholarship Fund of the China Scholarship Council (NO.202008510081)。
文摘In LEO satellite communication networks,the number of satellites has increased sharply, the relative velocity of satellites is very fast, then electronic signal aliasing occurs from time to time. Those aliasing signals make the receiving ability of the signal receiver worse, the signal processing ability weaker,and the anti-interference ability of the communication system lower. Aiming at the above problems, to save communication resources and improve communication efficiency, and considering the irregularity of interference signals, the underdetermined blind separation technology can effectively deal with the problem of interference sensing and signal reconstruction in this scenario. In order to improve the stability of source signal separation and the security of information transmission, a greedy optimization algorithm can be executed. At the same time, to improve network information transmission efficiency and prevent algorithms from getting trapped in local optima, delete low-energy points during each iteration process. Ultimately, simulation experiments validate that the algorithm presented in this paper enhances both the transmission efficiency of the network transmission system and the security of the communication system, achieving the process of interference sensing and signal reconstruction in the LEO satellite communication system.
基金Project supported by the National Science Foundation of Sichuan Province (Grant No. 2022NSFSC0534)the Central Guidance on Local Science and Technology Development Fund of Sichuan Province (Grant No. 22ZYZYTS0064)+1 种基金the Chengdu Key Research and Development Support Program (Grant No. 2021-YF09-0016-GX)the Key Project of Sichuan Normal University (Grant No. XKZX-02)。
文摘In the field of single-server blind quantum computation(BQC), a major focus is to make the client as classical as possible. To achieve this goal, we propose two single-server BQC protocols to achieve verifiable universal quantum computation. In these two protocols, the client only needs to perform either the gate T(in the first protocol) or the gates H and X(in the second protocol). With assistance from a single server, the client can utilize his quantum capabilities to generate some single-qubit states while keeping the actual state of these qubits confidential from others. By using these single-qubit states, the verifiable universal quantum computation can be achieved.
文摘People’s lives have become easier and simpler as technology has proliferated.This is especially true with the Internet of Things(IoT).The biggest problem for blind people is figuring out how to get where they want to go.People with good eyesight need to help these people.Smart shoes are a technique that helps blind people find their way when they walk.So,a special shoe has been made to help blind people walk safely without worrying about running into other people or solid objects.In this research,we are making a new safety system and a smart shoe for blind people.The system is based on Internet of Things(IoT)technology and uses three ultrasonic sensors to allow users to hear and react to barriers.It has ultrasonic sensors and a microprocessor that can tell how far away something is and if there are any obstacles.Water and flame sensors were used,and a sound was used to let the person know if an obstacle was near him.The sensors use Global Positioning System(GPS)technology to detect motion from almost every side to keep an eye on them and ensure they are safe.To test our proposal,we gave a questionnaire to 100 people.The questionnaire has eleven questions,and 99.1%of the people who filled it out said that the product meets their needs.
基金supported by the National Natural Science Foundation of China(61971165)the Key Research and Development Program of Hubei Province(2020BAB113)。
文摘Previous deep learning-based super-resolution(SR)methods rely on the assumption that the degradation process is predefined(e.g.,bicubic downsampling).Thus,their performance would suffer from deterioration if the real degradation is not consistent with the assumption.To deal with real-world scenarios,existing blind SR methods are committed to estimating both the degradation and the super-resolved image with an extra loss or iterative scheme.However,degradation estimation that requires more computation would result in limited SR performance due to the accumulated estimation errors.In this paper,we propose a contrastive regularization built upon contrastive learning to exploit both the information of blurry images and clear images as negative and positive samples,respectively.Contrastive regularization ensures that the restored image is pulled closer to the clear image and pushed far away from the blurry image in the representation space.Furthermore,instead of estimating the degradation,we extract global statistical prior information to capture the character of the distortion.Considering the coupling between the degradation and the low-resolution image,we embed the global prior into the distortion-specific SR network to make our method adaptive to the changes of distortions.We term our distortion-specific network with contrastive regularization as CRDNet.The extensive experiments on synthetic and realworld scenes demonstrate that our lightweight CRDNet surpasses state-of-the-art blind super-resolution approaches.
基金Project supported by the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2022JQ-701)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(Grant No.21JK0919)。
文摘Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better crystal quality,which is verified from x-ray diffraction(XRD)and scanning electron microscope(SEM)results.The Ga_(2)O_(3)-based solar blind photodetectors with different thicknesses are fabricated and studied.The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness.The photodetectors with inter-fingered structure based on 900 growth cyclesβ-Ga_(2)O_(3)active layers(corresponding film thickness of 58 nm)exhibit the best performances including a low dark current of 134 fA,photo-to-dark current ratio of 1.5×10^(7),photoresponsivity of 1.56 A/W,detectivity of 2.77×10^(14)Jones,and external quantum efficiency of 764.49%at a bias voltage of 10 V under 254-nm DUV illumination.The photoresponse rejection ratio(R_(254)/R_(365))is up to 1.86×10^(5).In addition,we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure.As the finger spacing decreases from 50μm to10μW,the photoresponsivity,detectivity,and external quantum efficiency increase significantly.
文摘Objective:Preventive measures and appropriate rehabilitation are important in reducing the social burden of blindness.This study was to evaluate the etiologies,proportions,and level of rehabilitation for patients with blindness.Materials and Methods:A prospective observational study with 1000 visually impaired patients was conducted.The data regarding age,gender,socioeconomic status(SES),etiologies,curable or incurable blindness(IB),treatments,awareness,and state of rehabilitation were collected and reviewed.Results:The ratio of curable to IB was 0.82:1.The proportion of blindness rises after 40,even while the proportion of curable blindness(CB)increases after 60.The male–female ratios were 1.25:1 and 1:1.66 in the cases of CB and IB,respectively.On the other hand,the male–female ratio for childhood blindness was 1.66:1.Cataracts(78.22%)were the most common cause of CB,whereas diabetic retinopathy(24%),corneal opacity(17.5%),and trauma(12.4%)were causes of IB.Patients with illiteracy,low SES,and female gender were more likely to develop IB.There were low enrollment rates at the blind school and poor rehabilitation,mainly because of a lack of knowledge.Conclusion:Diabetic retinopathy,corneal opacity,and trauma are the major causes of IB.IB and poor rehabilitation were more profound in women and were associated with illiteracy,low SES,and a lack of awareness.
文摘Visuality can be generically described as the quality of the visual,that is,as the given visual field in which a subject’s attention is concentrated.In fact,the visual is intrinsically linked to human vision,and this presupposes the existence of a visible horizon from which(visual)images are given.However,this formulation presents something uncanny paradoxical because it forgets,on one hand,the broader status of the image(such as auditory and olfactory images)-seeing is not just a visual process(at least since Diderot we know it)and there are mental mechanisms in the visual constitution process that help to fabricate reality and that gestalt theory has explained-and on the other hand,the possibility of seeing beyond what is visible,after all,everything(or almost everything)that presents itself in a digital and virtual environment it can be quite ontologically suspect.Based on some of these premises,we will trace a path of analysis that leads us to the current blindness:unconditional faith in digital technology and the fragile hope of happiness in a way that rejects the reality of the visible.
文摘He carefully pulled open the unlocked,light grey security door and saw an outdated,pale yellow plywood door.He was thrilled.His previous experience in lockpicking helped him effortlessly enter this shabby apartment.Rumour had it that such kind of apartments might contain secret treasure of corrupt officials.He inserted his tools into the keyhole,and the door clicked open.This simple lock was too easy for him to open with his professional skills.He could not help thinking the host was a fool.
基金Supported by SightFirst grant(No.SF 1825/UND)from Lions Clubs International Foundation,Oak Brook,IL,USA.
文摘AIM:To estimate the prevalence of blindness and visual impairment resulting from cataract in the population aged≥50 y in Hungary,and to assess the cataract surgical services.METHODS:A rapid assessment of avoidable blindness(RAAB)was conducted.A total of 3523 eligible people were randomly selected and examined.Each participant underwent surgery for cataract was interviewed with regard to the year,place,and costs of the surgery.Participants with obvious cataract were asked why they had not yet undergone surgery(barriers to surgery).RESULTS:An estimated 12514 people were bilaterally blind;the visual acuity(VA)in 19293 people was<6/60,and the VA in 73962 people was<6/18 in the better eye due to cataract.An estimated 77933 eyes are blind;98067 eyes had a VA of<6/60,and an estimated 277493 eyes had a VA of<6/18 due to cataract.Almost all cataract surgeries were conducted in government hospitals.The age-and sexadjusted cataract surgical coverage with VA<3/60 in eyes was 90.0%.The rate of good visual outcome after surgery was 79.5%.Ocular comorbidity was the main cause of poor outcome(78.1%),followed by late complications(such as posterior capsule opacification)(17.2%),inadequate optical correction(3.1%),and surgical complications(1.6%).The main barrier to surgery in people with bilateral cataract and VA of<6/60 was‘need not felt’.CONCLUSION:The prevalence of visual impairment resulting from cataract is slightly higher than expected.The quality of the cataract surgical service seems adequate in Hungary.However,the number of cataract operations per year should continue to increase due to the increasing patient demands and the aging population.
基金Supported by the National Natural Science Foundation of China(No.61340034)the Research Program of Application Foundation and Advanced Technology of Tianjin(No.13JCYBJC15600)
文摘As an ill-posed problem, multiframe blind super resolution imaging recovers a high resolution image from a group of low resolution images with some degradations when the information of blur kernel is limited. Note that the quality of the recovered image is influenced more by the accuracy of blur estimation than an advanced regularization. We study the traditional model of the multiframe super resolution and modify it for blind deblurring. Based on the analysis, we proposed two algorithms. The first one is based on the total variation blind deconvolution algorithm and formulated as a functional for optimization with the regularization of blur. Based on the alternating minimization and the gradient descent algorithm, the high resolution image and the unknown blur kernel are estimated iteratively. By using the median shift and add operator, the second algorithm is more robust to the outlier influence. The MSAA initialization simplifies the interpolation process to reconstruct the blurred high resolution image for blind deblurring and improves the accuracy of blind super resolution imaging. The experimental results demonstrate the superiority and accuracy of our novel algorithms.
文摘Speech recognition rate will deteriorate greatly in human-machine interaction when the speaker's speech mixes with a bystander's voice. This paper proposes a time-frequency approach for Blind Source Seperation (BSS) for intelligent Human-Machine Interaction(HMI). Main idea of the algorithm is to simultaneously diagonalize the correlation matrix of the pre-whitened signals at different time delays for every frequency bins in time-frequency domain. The prososed method has two merits: (1) fast convergence speed; (2) high signal to interference ratio of the separated signals. Numerical evaluations are used to compare the performance of the proposed algorithm with two other deconvolution algorithms. An efficient algorithm to resolve permutation ambiguity is also proposed in this paper. The algorithm proposed saves more than 10% of computational time with properly selected parameters and achieves good performances for both simulated convolutive mixtures and real room recorded speeches.
文摘In blind quantum computation(BQC),a client with weak quantum computation capabilities is allowed to delegate its quantum computation tasks to a server with powerful quantum computation capabilities,and the inputs,algorithms and outputs of the quantum computation are confidential to the server.Verifiability refers to the ability of the client to verify with a certain probability whether the server has executed the protocol correctly and can be realized by introducing trap qubits into the computation graph state to detect server deception.The existing verifiable universal BQC protocols are analyzed and compared in detail.The XTH protocol(proposed by Xu Q S,Tan X Q,Huang R in 2020),a recent improvement protocol of verifiable universal BQC,uses a sandglass-like graph state to further decrease resource expenditure and enhance verification capability.However,the XTH protocol has two shortcomings:limitations in the coloring scheme and a high probability of accepting an incorrect computation result.In this paper,we present an improved version of the XTH protocol,which revises the limitations of the original coloring scheme and further improves the verification ability.The analysis demonstrates that the resource expenditure is the same as for the XTH protocol,while the probability of accepting the wrong computation result is reduced from the original minimum(0.866)^(d*)to(0.819)^(d^(*)),where d;is the number of repeated executions of the protocol.
文摘In this paper a closed-form approximated expression is proposed for the Intersymbol Interference (ISI) as a function of time valid during the entire stages of the non-blind adaptive deconvolution process and is suitable for the noisy, real and two independent quadrature carrier input case. The obtained expression is applicable for type of channels where the resulting ISI as a function of time can be described with an exponential model having a single time constant. Based on this new expression for the ISI as a function of time, the convergence time (or number of iteration number required for convergence) of the non-blind adaptive equalizer can be calculated. Up to now, the equalizer’s performance (convergence time and ISI as a function of time) could be obtained only via simulation when the channel coefficients were known. The new proposed expression for the ISI as a function of time is based on the knowledge of the initial ISI and channel power (which is measurable) and eliminates the need to carry out any more the above mentioned simulation. Simulation results indicate a high correlation between the simulated and calculated ISI (based on our proposed expression for the ISI as a function of time) during the whole deconvolution process for the high as well as for the low signal to noise ratio (SNR) condition.
基金National Natural Science Foundation of China (No. 81070716)
文摘AIM: To determine the prevalence and risk factors for eye diseases, blindness, and low vision in Tibet, and to assist the development of eye disease prevention and treatment schemes.METHODS: We carried out a survey of eye diseases among a population living at high altitude. A total of 1 115 Tibetan permanent residents aged 40 years or older from the towns and villages of Qushui County, Lhasa Prefecture, Tibet Autonomous Region, participated in this study. All participants completed a detailed questio-nnaire, and underwent presenting and pinhole visual acuity tests,and a comprehensive ophthalmic examination.RESULTS: There were 187 blind eyes (8.43%), 231 eyes with low vision (10.41% ). The leading cause of visual impairment was cataract of 55.0% (101/187) blindness and of 50.2% (116/231) low vision, followed by fundus lesions of 22.9% blindness and 23.8% low vision, while only a low prevalence of glaucoma of 9.6% blindness and 1.7% low vision was observed. The analysis of 2 219 eyes showed that the most common external eye disease was pterygium (27.2%) in Tibet.CONCLUSION: The high prevalence of blindness and low vision in the Tibetan population at high altitude is a serious public health issue. There is a need to establish and maintain an appropriate effective eye care program in Tibet.
基金supported by the National Natural Science Foundation of China(1127105011371183+2 种基金61403036)the Science and Technology Development Foundation of CAEP(2013A04030202013B0403068)
文摘Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context.This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noisy context based on Walsh-Hadamard transformation and block matrix(WHT-BM). The proposed algorithm constructs a system of noisy linear equations and utilizes all its coefficients to recover parity check matrix. It is able to make use of fault-tolerant feature of WHT, thus providing more accurate results and achieving better error performance in high raw bit error rate(BER) regions. Moreover, it is more computationally efficient with the use of the block matrix(BM) method.