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Countermeasure against blinding attack for single-photon detectors in quantum key distribution
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作者 Lianjun Jiang Dongdong Li +12 位作者 Yuqiang Fang Meisheng Zhao Ming Liu Zhilin Xie Yukang Zhao Yanlin Tang Wei Jiang Houlin Fang Rui Ma Lei Cheng Weifeng Yang Songtao Han Shibiao Tang 《Journal of Semiconductors》 EI CAS CSCD 2024年第4期76-81,共6页
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
关键词 quantum key distribution single photon detector blinding attack pulsed blinding attack COUNTERMEASURE quan-tum communication
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A quantum blind signature scheme based on dense coding for non-entangled states
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作者 邢柯 殷爱菡 薛勇奇 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期220-228,共9页
In some schemes, quantum blind signatures require the use of difficult-to-prepare multiparticle entangled states. By considering the communication overhead, quantum operation complexity, verification efficiency and ot... In some schemes, quantum blind signatures require the use of difficult-to-prepare multiparticle entangled states. By considering the communication overhead, quantum operation complexity, verification efficiency and other relevant factors in practical situations, this article proposes a non-entangled quantum blind signature scheme based on dense encoding. The information owner utilizes dense encoding and hash functions to blind the information while reducing the use of quantum resources. After receiving particles, the signer encrypts the message using a one-way function and performs a Hadamard gate operation on the selected single photon to generate the signature. Then the verifier performs a Hadamard gate inverse operation on the signature and combines it with the encoding rules to restore the message and complete the verification.Compared with some typical quantum blind signature protocols, this protocol has strong blindness in privacy protection,and higher flexibility in scalability and application. The signer can adjust the signature operation according to the actual situation, which greatly simplifies the complexity of the signature. By simultaneously utilizing the secondary distribution and rearrangement of non-entangled quantum states, a non-entangled quantum state representation of three bits of classical information is achieved, reducing the use of a large amount of quantum resources and lowering implementation costs. This improves both signature verification efficiency and communication efficiency while, at the same time, this scheme meets the requirements of unforgeability, non-repudiation, and prevention of information leakage. 展开更多
关键词 quantum blind signature dense coding non-entanglement Hadamard gate
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Quantum circuit-based proxy blind signatures:A novel approach and experimental evaluation on the IBM quantum cloud platform
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作者 娄小平 昝慧茹 徐雪娇 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期247-253,共7页
This paper presents a novel approach to proxy blind signatures in the realm of quantum circuits,aiming to enhance security while safeguarding sensitive information.The main objective of this research is to introduce a... This paper presents a novel approach to proxy blind signatures in the realm of quantum circuits,aiming to enhance security while safeguarding sensitive information.The main objective of this research is to introduce a quantum proxy blind signature(QPBS)protocol that utilizes quantum logical gates and quantum measurement techniques.The QPBS protocol is constructed by the initial phase,proximal blinding message phase,remote authorization and signature phase,remote validation,and de-blinding phase.This innovative design ensures a secure mechanism for signing documents without revealing the content to the proxy signer,providing practical security authentication in a quantum environment under the assumption that the CNOT gates are securely implemented.Unlike existing approaches,our proposed QPBS protocol eliminates the need for quantum entanglement preparation,thus simplifying the implementation process.To assess the effectiveness and robustness of the QPBS protocol,we conduct comprehensive simulation studies in both ideal and noisy quantum environments on the IBM quantum cloud platform.The results demonstrate the superior performance of the QPBS algorithm,highlighting its resilience against repudiation and forgeability,which are key security concerns in the realm of proxy blind signatures.Furthermore,we have established authentic security thresholds(82.102%)in the presence of real noise,thereby emphasizing the practicality of our proposed solution. 展开更多
关键词 proxy blind signature quantum circuits quantum computation IBM quantum cloud platform
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A Blind Batch Encryption and Public Ledger-Based Protocol for Sharing Sensitive Data
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作者 Zhiwei Wang Nianhua Yang +2 位作者 Qingqing Chen Wei Shen Zhiying Zhang 《China Communications》 SCIE CSCD 2024年第1期310-322,共13页
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
关键词 blind batch encryption data sharing onetime adaptive access public ledger security and privacy
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Robust blind image watermarking based on interest points
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作者 Zizhuo WANG Kun HU +3 位作者 Chaoyangfan HUANG Zixuan HU Shuo YANG Xingjun WANG 《虚拟现实与智能硬件(中英文)》 EI 2024年第4期308-322,共15页
Digital watermarking technology plays an essential role in the work of anti-counterfeiting and traceability.However,image watermarking algorithms are weak against hybrid attacks,especially geometric attacks,such as cr... Digital watermarking technology plays an essential role in the work of anti-counterfeiting and traceability.However,image watermarking algorithms are weak against hybrid attacks,especially geometric attacks,such as cropping attacks,rotation attacks,etc.We propose a robust blind image watermarking algorithm that combines stable interest points and deep learning networks to improve the robustness of the watermarking algorithm further.First,to extract more sparse and stable interest points,we use the Superpoint algorithm for generation and design two steps to perform the screening procedure.We first keep the points with the highest possibility in a given region to ensure the sparsity of the points and then filter the robust interest points by hybrid attacks to ensure high stability.The message is embedded in sub-blocks centered on stable interest points using a deep learning-based framework.Different kinds of attacks and simulated noise are added to the adversarial training to guarantee the robustness of embedded blocks.We use the ConvNext network for watermark extraction and determine the division threshold based on the decoded values of the unembedded sub-blocks.Through extensive experimental results,we demonstrate that our proposed algorithm can improve the accuracy of the network in extracting information while ensuring high invisibility between the embedded image and the original cover image.Comparison with previous SOTA work reveals that our algorithm can achieve better visual and numerical results on hybrid and geometric attacks. 展开更多
关键词 blind watermarking Robust region selection Geometric distortion Deep learning
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For LEO Satellite Networks: Intelligent Interference Sensing and Signal Reconstruction Based on Blind Separation Technology
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作者 Chengjie Li Lidong Zhu Zhen Zhang 《China Communications》 SCIE CSCD 2024年第2期85-95,共11页
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
关键词 blind source separation greedy optimization algorithm interference sensing LEO satellite communication networks signal reconstruction
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Exploring the meaning of care among lived experiences of patients with blindness:an interpretive phenomenological study
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作者 Mohammad Ali Mohammadi Mehdi Heidarzadeh +1 位作者 Saeed Mehri Mahmood Shamshiri 《Frontiers of Nursing》 2024年第3期319-326,共8页
Objective:To explore the meaning of care experienced by people with blindness in hospitals.Methods:Interpretive phenomenology along with the 6-step method of van Manen was used to conduct the study.Using purposeful sa... Objective:To explore the meaning of care experienced by people with blindness in hospitals.Methods:Interpretive phenomenology along with the 6-step method of van Manen was used to conduct the study.Using purposeful sampling,15 people with legal blindness were interviewed.Thematic analysis was used to isolate the meaning of care.Results:Five themes emerged:(a)nurses in the eyes of patients with blindness;(b)negligence in the caring moments;(c)being cared for in ambiguity;(d)Uncoordinated care;and(e)Psychological discomfor t.These sub-themes were condensed into an overarching theme titled as“marginalized patients inside the stereotypical healthcare system.”Conclusions:Lived experiences of patients with blindness revealed that hospitals provide stereotypic or inappropriate care for this minority group in society.Health professionals par ticularly nurses should be skilled to provide person-centered and coordinated care for patients with blindness. 展开更多
关键词 HOSPITALIZATION lived experience meaning of care people with blindness PHENOMENOLOGY
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Contrastive Learning for Blind Super-Resolution via A Distortion-Specific Network 被引量:1
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作者 Xinya Wang Jiayi Ma Junjun Jiang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2023年第1期78-89,共12页
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
关键词 blind super-resolution contrastive learning deep learning image super-resolution(SR)
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Thickness effect on solar-blind photoelectric properties of ultrathinβ-Ga_(2)O_(3)films prepared by atomic layer deposition 被引量:1
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作者 王少青 程妮妮 +6 位作者 王海安 贾一凡 陆芹 宁静 郝跃 刘祥泰 陈海峰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第4期707-713,共7页
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
关键词 β-Ga_(2)O_(3) film thickness solar blind photodetectors photoelectric response
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Blind quantum computation with a client performing different single-qubit gates
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作者 吴光阳 杨振 +3 位作者 严玉瞻 罗元茂 柏明强 莫智文 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期326-330,共5页
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
关键词 blind quantum computation verifiable blind quantum computation single server
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Smart Shoes Safety System for the Blind People Based on (IoT) Technology
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作者 Ammar Almomani Mohammad Alauthman +4 位作者 Amal Malkawi Hadeel Shwaihet Batool Aldigide Donia Aldabeek Karmen Abu Hamoodeh 《Computers, Materials & Continua》 SCIE EI 2023年第7期415-436,共22页
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
关键词 IOT smart shoe SENSORS GSM GPS ARDUINO blind people safety system
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Evaluation of the etiologies and rehabilitation status of patients with blindness: A prospective observational study
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作者 Sarmistha DAS Pankaj Kumar HALDER +3 位作者 Suchidipa RAY Akholu VADEO Kallol PAUL Sneha SARKAR 《Journal of Integrative Nursing》 2023年第4期286-291,共6页
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
关键词 Age AWARENESS blindNESS curable incurable REHABILITATION socioeconomic status
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The Cultural Paradigm of Visuality in Times of Blindness
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作者 Paulo Alexandre e Castro 《Cultural and Religious Studies》 2023年第5期238-240,共3页
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
关键词 VISUALITY visible DIDEROT MAGRITTE MERLEAU-PONTY blindNESS
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The Blind and the Thief
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作者 LI YONGKANG 《China Today》 2023年第9期75-75,共1页
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
关键词 blind dated YELLOW
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宁夏地区白内障患病率和手术覆盖率调查
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作者 张金金 陈琳 +5 位作者 田恬 刘海军 牛伟 张雪 季梦莉 庄文娟 《中华实验眼科杂志》 CAS CSCD 北大核心 2024年第3期279-284,共6页
目的调查宁夏地区成年人群白内障患病率、手术覆盖率和术后视力现状。方法采用多阶段整群随机抽样横断面研究,抽取宁夏地区10个调查点,对其中18岁及以上人群进行调查,调查内容包括调查问卷、身高、体质量测量,视力、眼压、眼底照相和裂... 目的调查宁夏地区成年人群白内障患病率、手术覆盖率和术后视力现状。方法采用多阶段整群随机抽样横断面研究,抽取宁夏地区10个调查点,对其中18岁及以上人群进行调查,调查内容包括调查问卷、身高、体质量测量,视力、眼压、眼底照相和裂隙灯显微镜检查。分析白内障患病情况及其影响因素,调查受检人群不同年龄分组情况下白内障患病率、手术覆盖率及白内障术后生活视力(PVA)和最佳矫正视力(BCVA)情况。结果应检6145人,实际检查人数5721人,受检率为93.10%。受检人群年龄为18~93岁,平均(64.27±13.48)岁;男性2558人,占44.71%;女性3163人,占55.28%。其中,确诊为白内障患者1180例,白内障患病率为20.62%。白内障患病率随着年龄增长而升高,随受教育程度的升高而逐步下降,差异均有统计学意义(χ^(2)=1091.32、581.92,均P<0.01);患有高血压、糖尿病、高血脂、冠心病人群的白内障患病率明显高于无相应疾病的人群,差异均有统计学意义(χ^(2)=274.65、118.15、78.05、182.71,均P<0.01)。白内障患病人群中行白内障手术者245例,手术覆盖率为20.76%,其中人工晶状体植入229例,植入率93.40%;白内障盲社会负担率为2.29%,并随着年龄的增长而升高。行白内障手术的339眼中241眼PVA≥0.3,占71.09%,272眼BCVA≥0.3,占80.24%。结论白内障仍是宁夏地区高龄人群视力损伤甚至盲的主要原因,白内障盲社会负担率较高;宁夏地区白内障手术覆盖率较低,手术数量和质量均有待提高。 展开更多
关键词 白内障 患病率 手术覆盖率 白内障盲社会负担率 宁夏
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基于盲源分离的工业谐波源负荷分类识别方法 被引量:1
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作者 张逸 陈书畅 +1 位作者 刘必杰 林才华 《中国电机工程学报》 EI CSCD 北大核心 2024年第10期3850-3861,I0009,共13页
针对传统谐波源辨识方法无法实现工业用户谐波源具体类型的非侵入式识别的问题,该文提出一种基于盲源分离的工业谐波源负荷分类识别方法。该方法仅依据工业用户进线处电压、电流数据即可实现谐波源负荷具体类型的非侵入式识别。首先,从... 针对传统谐波源辨识方法无法实现工业用户谐波源具体类型的非侵入式识别的问题,该文提出一种基于盲源分离的工业谐波源负荷分类识别方法。该方法仅依据工业用户进线处电压、电流数据即可实现谐波源负荷具体类型的非侵入式识别。首先,从负荷等值阻抗模型入手,建立工业用户多负荷等值阻抗并联电路模型;其次,采用集合经验模态分解与奇异值分解相结合的方法确定构成用户进线处监测点综合等值阻抗信号的源阻抗信号数目;然后,采用快速独立分量分析实现将谐波源负荷等值阻抗信号从综合负荷等值阻抗信号中分离;最后,将分离出谐波源负荷等值阻抗信号频率特征与典型谐波源负荷进行匹配,进而实现分类识别。仿真与实测实验结果均表明,所提方法能够准确识别工业用户所含多种谐波源负荷的具体类型,具有较好的可行性和实用性。 展开更多
关键词 谐波源识别 负荷等值阻抗 盲源分离 源信号数目估计
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自攻螺钉与拉铆钉混合连接受剪承载性能试验
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作者 褚云朋 伏金蓉 +1 位作者 钟志豪 陈晓强 《工程科学与技术》 EI CAS CSCD 北大核心 2024年第4期88-97,共10页
为改善自攻螺钉连接的构件在地震作用下易发生拉脱导致结构严重破坏的缺点,提升冷弯薄壁型钢组合墙体抗破坏能力,分析了组合墙体层间连接处的传力机理,针对自攻螺钉的破坏模式,提出拉铆钉与自攻螺钉混合连接。为研究混合连接的抗剪性能... 为改善自攻螺钉连接的构件在地震作用下易发生拉脱导致结构严重破坏的缺点,提升冷弯薄壁型钢组合墙体抗破坏能力,分析了组合墙体层间连接处的传力机理,针对自攻螺钉的破坏模式,提出拉铆钉与自攻螺钉混合连接。为研究混合连接的抗剪性能,共进行了48组连接接头抗剪性能试验,包含冷弯薄壁型钢结构常用的5种连接板厚度,不同搭接板厚比(变化范围1.0~2.0),包含纯自攻螺钉连接、纯拉铆钉连接及混合连接的连接方式。观察混合连接的破坏模式,自攻螺钉未发现拉脱破坏,其破坏模式主要表现为:板承压破坏与螺钉倾斜组合破坏、铆钉剪断破坏及板承压与铆钉部分剪断组合破坏3种;相较单一连接方式,混合连接荷载–位移曲线表现出更长的塑性阶段;当板厚比大于1.5且组合板厚小于3.0mm,混合连接的承载力及延性较单一连接增长明显;利用现有计算方法对混合连接的承载力进行累加计算,与试验结果对比,计算结果偏保守。研究发现:混合连接能较好地弥补拉铆钉和自攻螺钉受剪过程中的缺陷,有效改善自攻螺钉拉脱破坏,从而提升连接的承载力及延性;板厚和板厚比是影响混合连接破坏模式及承载力的重要因素,与单一连接相比,板厚比越大,承载力提升越大;排布方式对混合连接的力学性能及破坏机理影响有限;在本文试验工况下,结合混合连接的破坏模式,在现有计算方法的基础上,提出改善后的计算方法,其计算结果更合理。 展开更多
关键词 拉铆钉连接 拉铆钉-螺钉混合连接 组合墙体 受剪性能 抗剪承载力计算方法
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重氮试验在盲插鼻肠管时末端位置判断中的应用效果研究
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作者 宋淳 温坤 +4 位作者 张鲁 仲秀玲 李燕 李丽 王晓云 《军事护理》 CSCD 北大核心 2024年第9期42-45,共4页
目的探讨重氮试验在盲插鼻肠管后末端位置判断的应用效果。方法采用便利抽样法,选取2021年9月至2022年1月山东省某三级甲等医院重症监护病房(intensive care unit,ICU)进行盲插鼻肠管术的216名患者为研究对象。采用重氮试验、测pH值、... 目的探讨重氮试验在盲插鼻肠管后末端位置判断的应用效果。方法采用便利抽样法,选取2021年9月至2022年1月山东省某三级甲等医院重症监护病房(intensive care unit,ICU)进行盲插鼻肠管术的216名患者为研究对象。采用重氮试验、测pH值、观察回抽液性质三种方式预测鼻肠管末端位置,以X线摄片为判定的金标准,确认鼻肠管末端位置。比较重氮试验及其他两种方式预测的准确率、敏感度、特异度、阳性结果预测值(positive predictive value,PPV)、阴性结果预测值(negative predictive value,NPV)、阳性似然比(positive likelihood ratio,PLR)、阴性似然比(negative likelihood ratio,NLR)等指标。结果pH值判断的敏感度为97.7%、NPV为84.0%、NLR为0.045;回抽液性质判断的特异度为82.9%、PPV为95.5%、PLR为4.912;重氮试验方式的准确率为92.6%、Kappa系数为0.755;受试者操作特征曲线下面积最大为0.870,95%CI(0.793,0.947)。结论重氮试验判断盲插鼻肠管末端位置的准确率、一致性较好,具有较高的临床预测价值。 展开更多
关键词 鼻肠管 盲插法 重氮试验 管道位置 判断方式
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单边螺栓T型钢连接梁柱节点地震损伤性能评估
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作者 布欣 孙海粟 +1 位作者 刘欢欢 王新武 《建筑钢结构进展》 CSCD 北大核心 2024年第1期22-29,53,共9页
随着装配式钢结构在建筑工程领域的应用日益广泛,单边螺栓连接作为一种高效、便捷的连接方式,逐渐受到业界的青睐。H型钢梁、方钢管柱通过T型钢连接件和单边螺栓连接技术形成新型装配式钢框架结构,梁柱节点作为整个框架体系的核心,其抗... 随着装配式钢结构在建筑工程领域的应用日益广泛,单边螺栓连接作为一种高效、便捷的连接方式,逐渐受到业界的青睐。H型钢梁、方钢管柱通过T型钢连接件和单边螺栓连接技术形成新型装配式钢框架结构,梁柱节点作为整个框架体系的核心,其抗震性能对整体结构的影响至关重要。为评估单边螺栓T型钢连接梁柱节点在地震过程中的损伤情况,开展了4种不同刚度单边螺栓T型钢连接梁柱节点的拟静力试验。通过试验,获得了单边螺栓T型钢连接梁柱节点的破坏模式、滞回性能和初始转动刚度,分析了不同刚度的T型钢连接件对梁柱节点的破坏模式、抗弯承载能力和转动刚度退化的影响。采用考虑残余变形累积损伤修正的Park-Ang损伤指数模型研究了试验中节点的损伤演化规律,结果表明:所提出的地震损伤模型能够较好地反映单边螺栓T型钢连接梁柱节点的损伤演化过程与破坏程度,为该类梁柱连接节点的优化设计和安全评估提供了理论依据和实践经验。 展开更多
关键词 单边螺栓 梁柱节点 抗震性能 损伤模型 损伤评估
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动态变化混叠模型下盲源分离中的源数估计
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作者 白琳 温媛媛 李栋 《电讯技术》 北大核心 2024年第3期396-401,共6页
在进行欠定盲分离时,特别是对于源信号数目及混合矩阵动态变化的情况,常规的欠定盲分离及源数估计方法不能对源信号数目的变化时刻做出判断,因此很难实现动态变化的源信号数目实时和准确的估计。针对这个问题,提出了一种动态变化混叠模... 在进行欠定盲分离时,特别是对于源信号数目及混合矩阵动态变化的情况,常规的欠定盲分离及源数估计方法不能对源信号数目的变化时刻做出判断,因此很难实现动态变化的源信号数目实时和准确的估计。针对这个问题,提出了一种动态变化混叠模型下欠定盲源分离中的源数估计方法。首先,建立动态变化混叠情形下盲源分离的数学模型及动态标识矩阵。其次,基于构建的动态标识矩阵统计和判断动态源信号数目的变化情况。最后,通过分段时间内多维观测矢量采样点聚类区间局部峰值统计,实现动态变化混叠模型下盲源分离中的源信号数目的有效估计。仿真结果表明,该方法能有效实现动态变化混叠模型下欠定盲源分离中的源数估计,并且信号估计效果良好。 展开更多
关键词 欠定盲源分离 源数估计 标识矩阵
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