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基于OBE背景的Access数据库课程实践教学探索
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作者 刘雨潇 《办公自动化》 2025年第1期35-38,共4页
为强化大学生的计算机应用技能,并培养他们运用合理的方法和工具解决实际问题的能力,基于对OBE(Outcome-Based Education,即结果导向教育)理念的深刻认识,对通识教育中的必修课程——Access数据库应用进行创新性的教学改革。不仅对课程... 为强化大学生的计算机应用技能,并培养他们运用合理的方法和工具解决实际问题的能力,基于对OBE(Outcome-Based Education,即结果导向教育)理念的深刻认识,对通识教育中的必修课程——Access数据库应用进行创新性的教学改革。不仅对课程教学目标进行全新的设计,还制定学习成效的检测与评价标准,以确保教学改革的实施效果。以Access数据库应用这门课程为例,对其调研报告和课程综合作业的评价量规设计进行深入地探讨,并详细阐述这些评价量规在提升学生学习效果、检验教学成果方面所发挥的重要作用。这些评价量规不仅有助于指导学生学习,还能为教师提供有效的教学反馈。通过应用教学的实践,发现评价量规对优化课程教学和提升培养目标具有显著的指导和支持作用。简而言之,通过改革教学方式和引入评价量规,成功地提高大学生的计算机应用能力,并帮助他们更好地利用技术和工具解决实际问题。这些教学创新不仅显著提高课程的教学品质,同时也为学生的长期学术进步和职业生涯规划奠定牢固的基础。 展开更多
关键词 OBE 计算机基础课程 access 教学实践 数据库
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Difficulty removing a totally implantable venous access port:A case report
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作者 Jing Chen Mu Tang +4 位作者 Qin-Yuan Han Lei Tang Teng-Hua Yu Yan-Ping Zhao Chong-Wu He 《World Journal of Clinical Cases》 2025年第13期41-46,共6页
BACKGROUND This case report examines the challenges associated with removing a totally implantable venous access port(TIVAP)used for long-term chemotherapy in a patient with breast cancer.Prolonged use of TIVAPs can r... BACKGROUND This case report examines the challenges associated with removing a totally implantable venous access port(TIVAP)used for long-term chemotherapy in a patient with breast cancer.Prolonged use of TIVAPs can result in complications such as catheter kinking,thrombosis,and adhesions between the catheter and surrounding tissues,potentially complicating their removal.CASE SUMMARY A breast cancer patient with bone metastasis presented with difficulty aspirating blood from a TIVAP that had been placed in the right internal jugular vein for 3 years.Initial removal attempts at the Department of Venous Access Center were unsuccessful,likely due to adhesions,necessitating a subsequent successful catheter extraction in a hybrid operating room.Imaging revealed no abnor-malities,and the catheter was removed using a mosquito clamp to detach it from surrounding tissues.CONCLUSION This case highlights the challenges of removing TIVAPs inserted via the internal jugular vein,particularly when the catheter traverses the sternocleidomastoid muscle.Repeated neck movements might lead to significant adhesions around the catheter,complicating its removal.Careful consideration should be given during catheter placement to avoid muscle-related adhesions and facilitate smoother extraction in long-term use. 展开更多
关键词 Internal jugular vein REMOVE Totally implantable venous access port CATHETER Case report
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Ultra-Dense LEO Satellite-Aircraft Access and Service Management in Civil Aviation
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作者 Wang Yilei Ma Ting +3 位作者 Liu Xiaoyu Gao Zhuxuan Zhou Haibo Shen Xuemin 《China Communications》 2025年第1期277-292,共16页
With the deployment of ultra-dense low earth orbit(LEO)satellite constellations,LEO satellite access network(LEO-SAN)is envisioned to achieve global Internet coverage.Meanwhile,the civil aviation communications have i... With the deployment of ultra-dense low earth orbit(LEO)satellite constellations,LEO satellite access network(LEO-SAN)is envisioned to achieve global Internet coverage.Meanwhile,the civil aviation communications have increased dramatically,especially for providing airborne Internet services.However,due to dynamic service demands and onboard LEO resources over time and space,it poses huge challenges in satellite-aircraft access and service management in ultra-dense LEO satellite networks(UDLSN).In this paper,we propose a deep reinforcement learning-based approach for ultra-dense LEO satellite-aircraft access and service management.Firstly,we develop an airborne Internet architecture based on UDLSN and design a management mechanism including medium earth orbit satellites to guarantee lightweight management.Secondly,considering latency-sensitive and latency-tolerant services,we formulate the problem of satellite-aircraft access and service management for civil aviation to ensure service continuity.Finally,we propose a proximal policy optimization-based access and service management algorithm to solve the formulated problem.Simulation results demonstrate the convergence and effectiveness of the proposed algorithm with satisfying the service continuity when applying to the UDLSN. 展开更多
关键词 civil aviation deep reinforcement learning satellite-aircraft access service management ultra-dense LEO satellite network
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Correlation between psychological,family social support,and home nursing quality for an implanted venous access port
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作者 Heng-Ya Jia Li-Qun Yan +1 位作者 Xiao-Bei Liu Jie Cao 《World Journal of Psychiatry》 2025年第2期130-139,共10页
BACKGROUND Cancer patients with an implanted venous access port(IVAP)often manage their care at home during chemotherapy intervals,including maintaining the device,monitoring complications,and following medication ins... BACKGROUND Cancer patients with an implanted venous access port(IVAP)often manage their care at home during chemotherapy intervals,including maintaining the device,monitoring complications,and following medication instructions.Home care ensures continued support after discharge.However,due to factors such as age,gender,culture,psychological status,and family support,the quality of home care varies significantly.Understanding these factors can help provide targeted guidance to improve the care of cancer patients.AIM To explore IVAP chemotherapy on home care quality and its association with mental health and family support for cancer patients.METHODS This investigative study was based on a medical records system.It investigated the relationship between psychological status,family support,and home care quality in 180 patients with cancer undergoing IVAP chemotherapy.Psychological status was assessed using the State Anxiety Inventory(S-AI);family support was assessed using the Perceived Social Support Scale(PSSS),and home care quality was evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire(EORTC QLQ-C30).Pearson’s correlation and Structural Equation Modeling were used to analyze the interplay between these factors.RESULTS The average S-AI score was 47.52±14.47,PSSS was 52.48±12.64,and EORTC QLQ-C30 was 70.09±17.32.A substantial inverse relationship was observed between the EORTC QLQ-C30 and S-AI scores(r=-0.712).A significant positive correlation was found between the EORTC QLQ-C30 and the PSSS,with a correlation coefficient of(r=0.744).The multiple linear regression analysis indicated that family social support,psychological status,and average monthly family income were the main factors influencing the variation in the quality of home care,explaining 71.9%of the variation.The Structural Equation Modeling results indicated that psychological status acted as a partial mediator in the association between family social support and home care quality of life,explaining 32.78%of the mediation effect.CONCLUSION Psychological status and family social support positively impacted cancer patients’home care quality,with psychology partially mediating this effect. 展开更多
关键词 Implanted venous access port Cancer patient Home nursing life quality Family social support Psychological status
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Searchable Encryption with Access Control on Keywords in Multi-User Setting 被引量:2
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作者 Lei Li Chungen Xu +2 位作者 Xiaoling Yu Bennian Dou Cong Zuo 《Journal of Cyber Security》 2020年第1期9-23,共15页
Searchable encryption technology makes it convenient to search encrypted data with keywords for people.A data owner shared his data with other users on the cloud server.For security,it is necessary for him to build a ... Searchable encryption technology makes it convenient to search encrypted data with keywords for people.A data owner shared his data with other users on the cloud server.For security,it is necessary for him to build a fine-grained and flexible access control mechanism.The main idea of this paper is to let the owner classify his data and then authorizes others according to categories.The cloud server maintains a permission matrix,which will be used to verify whether a trapdoor is valid or not.In this way we can achieve access control and narrow the search range at the same time.We prove that our scheme can achieve index and trapdoor indistinguishability under chosen keywords attack security in the random oracles. 展开更多
关键词 Searchable encryption access control cloud computing permission assignment
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Mapping and measuring urban-rural inequalities in accessibility to social infrastructures 被引量:2
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作者 Chenmeng Guo Weiqi Zhou +1 位作者 Chuanbao Jing Dawa Zhaxi 《Geography and Sustainability》 CSCD 2024年第1期41-51,共11页
Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social inf... Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social infras-tructures in urban areas across various scales,with less attention to rural areas,where inequality can be more severe.Particularly,few have investigated the disparities of accessibility to social infrastructures between urban and rural areas.Here,using the Changsha-Zhuzhou-Xiangtan urban agglomeration,China,as an example,we investigated the inequality of accessibility in both urban and rural areas,and further compared the urban-rural difference.Accessibility was measured by travel time of residents to infrastructures.We selected four types of social infrastructures including supermarkets,bus stops,primary schools,and health care,which were funda-mentally important to both urban and rural residents.We found large disparities in accessibility between urban and rural areas,ranging from 20 min to 2 h.Rural residents had to spend one to two more hours to bus stops than urban residents,and 20 min more to the other three types of infrastructures.Furthermore,accessibility to multiple infrastructures showed greater urban-rural differences.Rural residents in more than half of the towns had no access to any infrastructure within 15 min,while more than 60%of the urban residents could access to all infrastructures within 15 min.Our results revealed quantitative accessibility gap between urban and rural areas and underscored the necessity of social infrastructures planning to address such disparities. 展开更多
关键词 accessIBILITY Social infrastructures Urban-rural difference INEQUALITY Regional sustainability
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Digital compass for multi-user beam access in mmWave cellular networks
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作者 Adel Aldalbahi Nazli Siasi +1 位作者 Asim Mazin Mohammed A.Jasim 《Digital Communications and Networks》 SCIE CSCD 2023年第4期879-886,共8页
Beamforming in stand-alone Millimeter-Wave(mmWave)communications results in prolonged access times and latencies due to the increased number of measurements required to determine the optimal beam directions at the Mob... Beamforming in stand-alone Millimeter-Wave(mmWave)communications results in prolonged access times and latencies due to the increased number of measurements required to determine the optimal beam directions at the Mobile Station(MS)and Base Station(BS),returning the highest received signal level.Therefore,dynamic and fast access schemes that meet the Third-Generation Partnership Project(3GPP)specifications are required here.Therefore,in this paper,a novel initial access scheme is proposed for multiple MS users by leveraging for the first time a digital compass in the access procedure.Namely,when a new MS joins the footprint of a BS,it probes the channel for beacon signaling about the BS direction,i.e.,broadcasted by a neighboring MS that completed beam association at previous time steps.Then,a digital compass is utilized to adjust the coordinates of the BS according to the location of the new MS.The proposed scheme is applied for a single and multi-user settings at various broadcasting approaches.This includes a single associated MS user that broadcasts information to a single incoming MS user,a single user that broadcasts signals to multiple incoming users,or all multiple associated users broadcast to multiple incoming users.Overall,the proposed schemes yield in notable efficiency in terms of the computational complexity,access times,power and energy consumption as compared to existing access schemes.Further,high success rates are achieved at the detriment of relatively higher cost. 展开更多
关键词 Millimeter wave Initial beam access Electronic compass BEAMFORMING access times Energy consumption
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A Blockchain-Based Access Control Scheme for Reputation Value Attributes of the Internet of Things 被引量:1
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作者 Hongliang Tian Junyuan Tian 《Computers, Materials & Continua》 SCIE EI 2024年第1期1297-1310,共14页
The Internet of Things(IoT)access controlmechanism may encounter security issues such as single point of failure and data tampering.To address these issues,a blockchain-based IoT reputation value attribute access cont... The Internet of Things(IoT)access controlmechanism may encounter security issues such as single point of failure and data tampering.To address these issues,a blockchain-based IoT reputation value attribute access control scheme is proposed.Firstly,writing the reputation value as an attribute into the access control policy,and then deploying the access control policy in the smart contract of the blockchain system can enable the system to provide more fine-grained access control;Secondly,storing a large amount of resources fromthe Internet of Things in Inter Planetary File System(IPFS)to improve system throughput;Finally,map resource access operations to qualification tokens to improve the performance of the access control system.Complete simulation experiments based on the Hyperledger Fabric platform.Fromthe simulation experimental results,it can be seen that the access control system can achieve more fine-grained and dynamic access control while maintaining high throughput and low time delay,providing sufficient reliability and security for access control of IoT devices. 展开更多
关键词 Blockchain IOT access control Hyperledger Fabric
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The impact of Internet access on household dietary quality:Evidence from rural China 被引量:1
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作者 Yi Cui Qiran Zhao +1 位作者 Thomas Glauben Wei Si 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第2期374-383,共10页
Over the past few decades,the Internet has rapidly diffused across China.The spread of the Internet has had a profound economic and social impact on Chinese rural areas.Existing research shows that Internet access sig... Over the past few decades,the Internet has rapidly diffused across China.The spread of the Internet has had a profound economic and social impact on Chinese rural areas.Existing research shows that Internet access significantly impacts agricultural production and improves smallholder farmers’income.Beyond these,the Internet can affect other dimensions of social welfare.However,research about the impact of Internet access on dietary quality in rural China remains scarce.This study utilizes multi-period panel data from Fixed Observation Point in rural China from 2009 to 2015 to estimate the impact of Internet access on dietary quality and food consumption of rural households and conducts a causal analysis.Regression models with time and household fixed effects allow robust estimation while reducing potential issues of unobserved heterogeneity.The estimates show that Internet access has significantly increased rural household dietary quality(measured by the Chinese Diet Balance Index).Further research finds that Internet access has increased the consumption of animal products,such as aquatic and dairy products.We also examine the underlying mechanisms.Internet access improves dietary quality and food consumption mainly through increasing household income and food expenditure.These results encourage the promotion of Internet access as a valuable tool for nutritional improvements,especially in rural areas. 展开更多
关键词 dietary quality fixed effect model Internet access rural China
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Development Of Multi-users Multi-function Watt-hour Meter Based On ATT7022B
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作者 Mao-fa GONG~1,Chang-lun HU~1,Jing-yin HE~2,Xiao-ming ZHANG~1,Long-qing CHAI~1 (1.Collage of information and electrical engineering,Shandong University Of Science and Technology,Qingdao266510,China 2.Qingdao Technical Collage,Qingdao 266555,China) 《Journal of Measurement Science and Instrumentation》 CAS 2010年第S1期123-125,共3页
According to the feature of city’s apartment building in China,a kind of Multi-users Watt-hour Meter based on ATT7022B has been developed in this paper.The master-slave MCU control model and the principles of Time Sh... According to the feature of city’s apartment building in China,a kind of Multi-users Watt-hour Meter based on ATT7022B has been developed in this paper.The master-slave MCU control model and the principles of Time Sharing Multiplex are adopted in this Watt-hour Meter,its function includes the measurement of current, voltage,power,power factor and the overload protection.It supports remote reading,pre-payment,multi-rate and etc. The practice shows that this meter has high accuracy,runs stable.It has wide prospect in the future market. 展开更多
关键词 multi-users ATT7022B Time Sharing Multiplex Master-Slave Control Mode
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Detection of Turbulence Anomalies Using a Symbolic Classifier Algorithm in Airborne Quick Access Record(QAR)Data Analysis 被引量:1
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作者 Zibo ZHUANG Kunyun LIN +1 位作者 Hongying ZHANG Pak-Wai CHAN 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第7期1438-1449,共12页
As the risks associated with air turbulence are intensified by climate change and the growth of the aviation industry,it has become imperative to monitor and mitigate these threats to ensure civil aviation safety.The ... As the risks associated with air turbulence are intensified by climate change and the growth of the aviation industry,it has become imperative to monitor and mitigate these threats to ensure civil aviation safety.The eddy dissipation rate(EDR)has been established as the standard metric for quantifying turbulence in civil aviation.This study aims to explore a universally applicable symbolic classification approach based on genetic programming to detect turbulence anomalies using quick access recorder(QAR)data.The detection of atmospheric turbulence is approached as an anomaly detection problem.Comparative evaluations demonstrate that this approach performs on par with direct EDR calculation methods in identifying turbulence events.Moreover,comparisons with alternative machine learning techniques indicate that the proposed technique is the optimal methodology currently available.In summary,the use of symbolic classification via genetic programming enables accurate turbulence detection from QAR data,comparable to that with established EDR approaches and surpassing that achieved with machine learning algorithms.This finding highlights the potential of integrating symbolic classifiers into turbulence monitoring systems to enhance civil aviation safety amidst rising environmental and operational hazards. 展开更多
关键词 turbulence detection symbolic classifier quick access recorder data
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Joint Multi-User Detection with Weighting Factors for Unsourced Multiple Access
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作者 Yu Liu Kai Niu Yuanjie Li 《Journal of Computer and Communications》 2023年第9期121-131,共11页
Multi-user detection techniques are currently being studied as highly promising technologies for improving the performance of unsourced multiple access systems. In this paper, we propose joint multi-user detection sch... Multi-user detection techniques are currently being studied as highly promising technologies for improving the performance of unsourced multiple access systems. In this paper, we propose joint multi-user detection schemes with weighting factors for unsourced multiple access. First, we introduce bidirectional weighting factors in the extrinsic information passing process between the multi-user detector based on belief propagation (BP) and the LDPC decoder. Second, we incorporate bidirectional weighting factors in the message passing process between the MAC nodes and the user variable nodes in BP- based multi-user detector. The proposed schemes select the optimal weighting factors through simulations. The simulation results demonstrate that the proposed schemes exhibit significant performance improvements in terms of block error rate (BLER) compared to traditional schemes. . 展开更多
关键词 COMMUNICATION Sparse IDMA multi-user Detection Belief Propagation
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Downlink network-coded multiple access with diverse power
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作者 Bohao Cao Zheng Xiang +2 位作者 Peng Ren Qiao Li Baoyi Xu 《Digital Communications and Networks》 SCIE CSCD 2024年第4期956-964,共9页
Normally,in the downlink Network-Coded Multiple Access(NCMA)system,the same power is allocated to different users.However,equal power allocation is unsuitable for some scenarios,such as when user devices have differen... Normally,in the downlink Network-Coded Multiple Access(NCMA)system,the same power is allocated to different users.However,equal power allocation is unsuitable for some scenarios,such as when user devices have different Quality of Service(QoS)requirements.Hence,we study the power allocation in the downlink NCMA system in this paper,and propose a downlink Network-Coded Multiple Access with Diverse Power(NCMA-DP),wherein different amounts of power are allocated to different users.In terms of the Bit Error Rate(BER)of the multi-user decoder,and the number of packets required to correctly decode the message,the performance of the user with more allocated power is greatly improved compared to the Conventional NCMA(NCMA-C).Meanwhile,the performance of the user with less allocated power is still much better than NCMA-C.Furthermore,the overall throughput of NCMA-DP is greatly improved compared to that of NCMA-C.The simulation results demonstrate the remarkable performance of the proposed NCMA-DP. 展开更多
关键词 Network-coded multiple access Physical-layer network coding multi-user decoder Power allocation Throughput Downlink network
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Access数据库技术及其应用研究 被引量:1
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作者 侯培杰 《信息与电脑》 2024年第3期149-151,共3页
文章主要研究Access数据库技术及其应用,首先介绍Access数据库技术的理论基础,包括数据库结构、数据库安全性、数据库存储空间,然后探讨Access数据库技术的应用方法,包括数据存储和管理、报表生成和打印、数据库设计和开发等,最后对基于... 文章主要研究Access数据库技术及其应用,首先介绍Access数据库技术的理论基础,包括数据库结构、数据库安全性、数据库存储空间,然后探讨Access数据库技术的应用方法,包括数据存储和管理、报表生成和打印、数据库设计和开发等,最后对基于Access数据库的实例应用进行分析,展示Access数据库在提高工作效率、优化数据管理和增强决策能力等方面的作用。 展开更多
关键词 access 数据库技术 应用
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基于BOPPPS模型和思维导图的Access数据库课程教学设计
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作者 于惠雯 赵艺洁 《集成电路应用》 2024年第1期82-83,共2页
阐述BOPPPS模式和思维导图开展Access数据库课程教学设计,分析BOPPPS模型和思维导图的特点,探讨Access数据库课程教学设计中的应用,包括课堂引入、课程目标、参与式学习、考试评估。
关键词 思维导图 access数据库 课程设计 BOPPPS模型
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Effectiveness of Ultrasound-Guided Arteriovenous Fistulas Cannulation in Difficult Hemodialysis Arteriovenous Access: A Meta-Analysis of Randomised Controlled Trials
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作者 Alison Hiu Ming Chan Angie Ho Yan Lam 《Health》 2024年第11期994-1012,共19页
Aim(s): Complex Arteriovenous fistula (AVF) poses challenges to cannulation. Ultrasound (US)-guided cannulation may promote successful cannulation and prevent AVF-related complications. Renal nurses performing US-guid... Aim(s): Complex Arteriovenous fistula (AVF) poses challenges to cannulation. Ultrasound (US)-guided cannulation may promote successful cannulation and prevent AVF-related complications. Renal nurses performing US-guided cannulation may improve successful cannulation and reduce complications associated with unnecessary punctures. The study aims to conduct the meta-analyze to examine the effectiveness of renal nurse-performed US-guided cannulation to improve successful cannulation and reduce AVF-related complications in difficult AVF access. Design: A meta-analysis of randomised controlled trials. Methods: A systemic search was performed on electronic databases including CINAHL Plus, Web of Science, and PubMed from inception to October 2023. Risk ratios (RR) and standardized mean differences (SMD) were estimated using random-effect models for considerable homogeneity, and the Scottish Intercollegiate Guidelines Network (SIGN) methodology was adopted for critical appraisal. Results: Four RCTs were included. The results showed US-guided AVF cannulation had a significant effect in improving successful cannulation (RR: 0.19, 95% CI: 0.06 to 0.63, p = 0.007), and was favorable in reducing cannulation-associated complications (RR: 0.44, 95% CI: 0.10 to 1.93, p = 0.28), compared with blind needle cannulation. Conclusion: US-guided cannulation performed by renal nurses has the potential to improve successful cannulation, and fewer complications in hemodialysis patients with difficult arteriovenous access. Relevance to Clinical Practice: The results suggest the value of further training for renal nurses in US-guided cannulation, and broader implementation of US-guided cannulation to improve patient outcomes. Future studies could explore the optimal nursing training and longer-term benefits of US-guided cannulation by renal nurses in difficult AVF access. Patient or Public Contribution: No Patient or Public Contribution as this is a meta-analysis using the secondary data published in the RCTs. 展开更多
关键词 Arteriovenous Fistula CANNULATION Dialysis access HEMODIALYSIS Renal Nurse Ultrasound Guidance Vascular access
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Access原发性肝癌数据库的建立及其应用价值分析
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作者 王海永 孔春丽 +2 位作者 周利芬 洪怀江 王祖飞 《数字通信世界》 2024年第12期108-110,共3页
目的:探讨Access原发性肝癌数据库的建立方法及其应用价值。方法:选择本院2020年1月至2024年4月期间确诊的原发性肝癌患者,数据来源为医院内局域网系统中的患者信息数据,通过Access数据库保存和管理患者的临床资料,建立原发性肝癌患者... 目的:探讨Access原发性肝癌数据库的建立方法及其应用价值。方法:选择本院2020年1月至2024年4月期间确诊的原发性肝癌患者,数据来源为医院内局域网系统中的患者信息数据,通过Access数据库保存和管理患者的临床资料,建立原发性肝癌患者的临床资料专科数据库。结果本院成功创建了原发性肝癌数据库并应用于临床诊疗、教学和科研等工作中。结论:建立原发性肝癌数据库并形成肝癌临床数据库管理系统,从而为临床诊疗工作和科研工作提供有效数据支撑,应用价值较高。 展开更多
关键词 原发性肝癌 access数据库 k均值聚类算法机器 SMITH-WATERMAN算法 应用价值
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Resource Allocation in Multi-User Cellular Networks:A Transformer-Based Deep Reinforcement Learning Approach
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作者 Zhao Di Zheng Zhong +2 位作者 Qin Pengfei Qin Hao Song Bin 《China Communications》 SCIE CSCD 2024年第5期77-96,共20页
To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing importance.In this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlin... To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing importance.In this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user fairness.We first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)approach.Specifically,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource sequence.Experimental results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance. 展开更多
关键词 dynamic resource allocation multi-user cellular network spectrum efficiency user fairness
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Power-Domain Collision-Tolerant Random Access Method with Auxiliary Beam for Satellite Internet of Things:A New Solution
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作者 Xu Yuanyuan Liu Ziwei +1 位作者 Bian Dongming Zhang Gengxin 《China Communications》 SCIE CSCD 2024年第8期236-248,共13页
There are numerous terminals in the satellite Internet of Things(IoT).To save cost and reduce power consumption,the system needs terminals to catch the characteristics of low power consumption and light control.The re... There are numerous terminals in the satellite Internet of Things(IoT).To save cost and reduce power consumption,the system needs terminals to catch the characteristics of low power consumption and light control.The regular random access(RA)protocols may generate large amounts of collisions,which degrade the system throughout severally.The near-far effect and power control technologies are not applicable in capture effect to obtain power difference,resulting in the collisions that cannot be separated.In fact,the optimal design at the receiving end can also realize the condition of packet power domain separation,but there are few relevant researches.In this paper,an auxiliary beamforming scheme is proposed for power domain signal separation.It adds an auxiliary reception beam based on the conventional beam,utilizing the correlation of packets in time-frequency domain between the main and auxiliary beam to complete signal separation.The roll-off belt of auxiliary beam is used to create the carrier-to-noise ratio(CNR)difference.This paper uses the genetic algorithm to optimize the auxiliary beam direction.Simulation results show that the proposed scheme outperforms slotted ALOHA(SA)in terms of system throughput per-formance and without bringing terminals additional control burden. 展开更多
关键词 beamforming non-orthogonal multiple access random access satellite Internet of Things
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The Extended Hybrid Carrier-Based Multiple Access Technology for High Mobility Scenarios 被引量:1
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作者 Ge Song Xiaojie Fang Xuejun Sha 《China Communications》 SCIE CSCD 2024年第1期53-68,共16页
The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communicatio... The hybrid carrier(HC)system rooted in the carrier fusion concept is gradually garnering attention.In this paper,we study the extended hybrid carrier(EHC)multiple access scheme to ensure reliable wireless communication.By employing the EHC modulation,a power layered multiplexing framework is realized,which exhibits enhanced interference suppression capability owing to the more uniform energy distribution design.The implementation method and advantage mechanism are explicated respectively for the uplink and downlink,and the performance analysis under varying channel conditions is provided.In addition,considering the connectivity demand,we explore the non-orthogonal multiple access(NOMA)method of the EHC system and develop the EHC sparse code multiple access scheme.The proposed scheme melds the energy spread superiority of EHC with the access capacity of NOMA,facilitating superior support for massive connectivity in high mobility environments.Simulation results have verified the feasibility and advantages of the proposed scheme.Compared with existing HC multiple access schemes,the proposed scheme exhibits robust bit error rate performance and can better guarantee multiple access performance in complex scenarios of nextgeneration communications. 展开更多
关键词 extended hybrid carrier system high mo-Received:Jun.09 2023 Revised:Nov.20 2023 Editor:Yuanwei Liu bility communications multiple access
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