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Hybrid Approach for Cost Efficient Application Placement in Fog-Cloud Computing Environments
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作者 Abdulelah Alwabel Chinmaya Kumar Swain 《Computers, Materials & Continua》 SCIE EI 2024年第6期4127-4148,共22页
Fog computing has recently developed as a new paradigm with the aim of addressing time-sensitive applications better than with cloud computing by placing and processing tasks in close proximity to the data sources.How... Fog computing has recently developed as a new paradigm with the aim of addressing time-sensitive applications better than with cloud computing by placing and processing tasks in close proximity to the data sources.However,the majority of the fog nodes in this environment are geographically scattered with resources that are limited in terms of capabilities compared to cloud nodes,thus making the application placement problem more complex than that in cloud computing.An approach for cost-efficient application placement in fog-cloud computing environments that combines the benefits of both fog and cloud computing to optimize the placement of applications and services while minimizing costs.This approach is particularly relevant in scenarios where latency,resource constraints,and cost considerations are crucial factors for the deployment of applications.In this study,we propose a hybrid approach that combines a genetic algorithm(GA)with the Flamingo Search Algorithm(FSA)to place application modules while minimizing cost.We consider four cost-types for application deployment:Computation,communication,energy consumption,and violations.The proposed hybrid approach is called GA-FSA and is designed to place the application modules considering the deadline of the application and deploy them appropriately to fog or cloud nodes to curtail the overall cost of the system.An extensive simulation is conducted to assess the performance of the proposed approach compared to other state-of-the-art approaches.The results demonstrate that GA-FSA approach is superior to the other approaches with respect to task guarantee ratio(TGR)and total cost. 展开更多
关键词 placement mechanism application module placement fog computing cloud computing genetic algorithm flamingo search algorithm
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Layered Coded Cache Placement and Cooperative Delivery with Sharing Links in Satellite-Terrestrial Integrated Networks
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作者 Gu Shushi Chen Zihan +2 位作者 Wu Yaonan Zhang Qinyu Wang Ye 《China Communications》 SCIE CSCD 2024年第3期217-229,共13页
Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content deliver... Cooperative utilization of multidimensional resources including cache, power and spectrum in satellite-terrestrial integrated networks(STINs) can provide a feasible approach for massive streaming media content delivery over the seamless global coverage area. However, the on-board supportable resources of a single satellite are extremely limited and lack of interaction with others. In this paper, we design a network model with two-layered cache deployment, i.e., satellite layer and ground base station layer, and two types of sharing links, i.e., terrestrial-satellite sharing(TSS) links and inter-satellite sharing(ISS) links, to enhance the capability of cooperative delivery over STINs. Thus, we use rateless codes for the content divided-packet transmission, and derive the total energy efficiency(EE) in the whole transmission procedure, which is defined as the ratio of traffic offloading and energy consumption. We formulate two optimization problems about maximizing EE in different sharing scenarios(only TSS and TSS-ISS),and propose two optimized algorithms to obtain the optimal content placement matrixes, respectively.Simulation results demonstrate that, enabling sharing links with optimized cache placement have more than 2 times improvement of EE performance than other traditional placement schemes. Particularly, TSS-ISS schemes have the higher EE performance than only TSS schemes under the conditions of enough number of satellites and smaller inter-satellite distances. 展开更多
关键词 coded content placement cooperative delivery energy efficiency sharing links STINs
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Characteristics of proppant transport and placement within rough hydraulic fractures
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作者 HUANG Hai ZHENG Yong +5 位作者 WANG Yi WANG Haizhu NI Jun WANG Bin YANG Bing ZHANG Wentong 《Petroleum Exploration and Development》 SCIE 2024年第2期453-463,共11页
A three-dimensional reconstruction of rough fracture surfaces of hydraulically fractured rock outcrops is carried out by casting process,a large-scale experimental setup for visualizing rough fractures is built to per... A three-dimensional reconstruction of rough fracture surfaces of hydraulically fractured rock outcrops is carried out by casting process,a large-scale experimental setup for visualizing rough fractures is built to perform proppant transport experiments.The typical characteristics of proppant transport and placement in rough fractures and its intrinsic mechanisms are investigated,and the influences of fracture inclination,fracture width and fracturing fluid viscosity on proppant transport and placement in rough fractures are analyzed.The results show that the rough fractures cause variations in the shape of the flow channel and the fluid flow pattern,resulting in the bridging buildup during proppant transport to form unfilled zone,the emergence of multiple complex flow patterns such as channeling,reverse flow and bypassing of sand-carrying fluid,and the influence on the stability of the sand dune.The proppant has a higher placement rate in inclined rough fractures,with a maximum increase of 22.16 percentage points in the experiments compared to vertical fractures,but exhibits poor stability of the sand dune.Reduced fracture width aggravates the bridging of proppant and induces higher pumping pressure.Increasing the viscosity of the fracturing fluid can weaken the proppant bridging phenomenon caused by the rough fractures. 展开更多
关键词 reservoir fracturing rough fracture PROPPANT transport and placement characteristics bridging buildup
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Analysis of the Application Effect of Tracheal Stent Placement in the Nutritional Support Treatment of Tracheoesophageal Fistula
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作者 Xiaoqing An Xiaoting An Yiqing Qu 《Proceedings of Anticancer Research》 2024年第3期104-108,共5页
Objective:To evaluate and analyze the application effect of tracheal stent placement in nutritional support therapy for tracheoesophageal fistula.Methods:Clinical data of 32 patients who underwent nutritional support ... Objective:To evaluate and analyze the application effect of tracheal stent placement in nutritional support therapy for tracheoesophageal fistula.Methods:Clinical data of 32 patients who underwent nutritional support therapy for tracheoesophageal fistula in our hospital from September 2021 to September 2022 were collected,and all patients underwent tracheal silicone stenting,comparing dyspnea classification and Karnofsky score before and after stenting,and conducting post-treatment follow-up.Results:In 32 patients with tracheoesophageal fistula,dyspnea grading improved from grades III and IV to grades 0 to II.Before treatment,10 patients(31.06%)were in grade IV,17 patients(53.12%)were in grade III,and five patients(15.62)were in grade II;after treatment,13 patients(40.63%)were in grade I,12 patients(37.50%)were in grade I,and seven patients(21.87%)were in grade 0(P<0.05);Karnofsky score(37.52±4.86 before treatment)improved significantly to 71.39±8.24 one week after treatment(P<0.05).Nine patients with tracheoesophageal fistula were placed with silicone Y14-10-10 stent,11 with silicone 18-14-14 stent,three with silicone Y15-12-12,and seven with silicone stent 16-13-13.Conclusion:Silicone tracheobronchial stent placement for the treatment of tracheoesophageal fistula is technically feasible,simple,and safe,with reliable near-term efficacy,and is worthy of popularization and application. 展开更多
关键词 Tracheal stent placement Tracheoesophageal fistula Nutritional support
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Clinical Study on Improving Articulation Clarity in Spastic Cerebral Palsy with 120 Cases of Oral-Facial Acupressure Combined with Oral Placement Therapy
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作者 Yongjie Gong Kai Wu +4 位作者 Shan Yang Yalan Yu Xiaobo Zhang Fei Rong Yuan He 《Journal of Clinical and Nursing Research》 2024年第5期30-38,共9页
Objective:To observe the efficacy of oral-facial acupressure combined with oral placement therapy(OPT)in improving articulation clarity in 120 children with spastic cerebral palsy,and to explore effective therapeutic ... Objective:To observe the efficacy of oral-facial acupressure combined with oral placement therapy(OPT)in improving articulation clarity in 120 children with spastic cerebral palsy,and to explore effective therapeutic solutions for speech disorders associated with spastic cerebral palsy.Methods:A total of 120 children with spastic cerebral palsy and speech disorders,meeting the inclusion criteria,were randomly assigned into two groups:60 cases in the treatment group and 60 cases in the control group.The treatment group received orofacial acupressure combined with OPT,while the control group received only OPT.The Oral Motor Function Assessment Scale(OMFAS),developed by the China Rehabilitation Research Centre(CRRC),was used to evaluate the treatment outcomes before and after the intervention.Results:After the treatment,both the treatment and control groups showed improved mobility of the mandible,lips,and tongue.However,the treatment group exhibited significantly better improvement than the control group,with the difference between the two groups being statistically significant(P<0.05).Conclusion:Oral-facial acupressure combined with OPT can effectively improve articulation clarity in children with spastic cerebral palsy.This combined therapy is recommended for clinical promotion and application. 展开更多
关键词 Oral-facial acupressure Oral placement therapy(OPT) Speech disorders in children with spastic cerebral palsy Speech intelligibility
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Sea Turtle Foraging Optimization-Based Controller Placement with Blockchain-Assisted Intrusion Detection in Software-Defined Networks
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作者 Sultan Alkhliwi 《Computers, Materials & Continua》 SCIE EI 2023年第6期4735-4752,共18页
Software-defined networking(SDN)algorithms are gaining increas-ing interest and are making networks flexible and agile.The basic idea of SDN is to move the control planes to more than one server’s named controllers a... Software-defined networking(SDN)algorithms are gaining increas-ing interest and are making networks flexible and agile.The basic idea of SDN is to move the control planes to more than one server’s named controllers and limit the data planes to numerous sending network components,enabling flexible and dynamic network management.A distinctive characteristic of SDN is that it can logically centralize the control plane by utilizing many physical controllers.The deployment of the controller—that is,the controller placement problem(CPP)—becomes a vital model challenge.Through the advancements of blockchain technology,data integrity between nodes can be enhanced with no requirement for a trusted third party.Using the lat-est developments in blockchain technology,this article designs a novel sea turtle foraging optimization algorithm for the controller placement problem(STFOA-CPP)with blockchain-based intrusion detection in an SDN environ-ment.The major intention of the STFOA-CPP technique is the maximization of lifetime,network connectivity,and load balancing with the minimization of latency.In addition,the STFOA-CPP technique is based on the sea turtles’food-searching characteristics of tracking the odour path of dimethyl sulphide(DMS)released from food sources.Moreover,the presented STFOA-CPP technique can adapt with the controller’s count mandated and the shift to controller mapping to variable network traffic.Finally,the blockchain can inspect the data integrity,determine significantly malicious input,and improve the robust nature of developing a trust relationship between sev-eral nodes in the SDN.To demonstrate the improved performance of the STFOA-CPP algorithm,a wide-ranging experimental analysis was carried out.The extensive comparison study highlighted the improved outcomes of the STFOA-CPP technique over other recent approaches. 展开更多
关键词 Software-defined networking NP hard problem metaheuristics controller placement problem objective function
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Multi-Layer Fog-Cloud Architecture for Optimizing the Placement of IoT Applications in Smart Cities
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作者 Mohammad Aldossary 《Computers, Materials & Continua》 SCIE EI 2023年第4期633-649,共17页
In the smart city paradigm, the deployment of Internet of Things(IoT) services and solutions requires extensive communication and computingresources to place and process IoT applications in real time, which consumesa ... In the smart city paradigm, the deployment of Internet of Things(IoT) services and solutions requires extensive communication and computingresources to place and process IoT applications in real time, which consumesa lot of energy and increases operational costs. Usually, IoT applications areplaced in the cloud to provide high-quality services and scalable resources.However, the existing cloud-based approach should consider the above constraintsto efficiently place and process IoT applications. In this paper, anefficient optimization approach for placing IoT applications in a multi-layerfog-cloud environment is proposed using a mathematical model (Mixed-Integer Linear Programming (MILP)). This approach takes into accountIoT application requirements, available resource capacities, and geographicallocations of servers, which would help optimize IoT application placementdecisions, considering multiple objectives such as data transmission, powerconsumption, and cost. Simulation experiments were conducted with variousIoT applications (e.g., augmented reality, infotainment, healthcare, andcompute-intensive) to simulate realistic scenarios. The results showed thatthe proposed approach outperformed the existing cloud-based approach interms of reducing data transmission by 64% and the associated processingand networking power consumption costs by up to 78%. Finally, a heuristicapproach was developed to validate and imitate the presented approach. Itshowed comparable outcomes to the proposed model, with the gap betweenthem reach to a maximum of 5.4% of the total power consumption. 展开更多
关键词 IoT application placement fog-cloud computing power consumption data transmission optimization smart cities
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Improved Harris Hawks Optimization Algorithm Based Data Placement Strategy for Integrated Cloud and Edge Computing
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作者 V.Nivethitha G.Aghila 《Intelligent Automation & Soft Computing》 SCIE 2023年第7期887-904,共18页
Cloud computing is considered to facilitate a more cost-effective way to deploy scientific workflows.The individual tasks of a scientific work-flow necessitate a diversified number of large states that are spatially l... Cloud computing is considered to facilitate a more cost-effective way to deploy scientific workflows.The individual tasks of a scientific work-flow necessitate a diversified number of large states that are spatially located in different datacenters,thereby resulting in huge delays during data transmis-sion.Edge computing minimizes the delays in data transmission and supports the fixed storage strategy for scientific workflow private datasets.Therefore,this fixed storage strategy creates huge amount of bottleneck in its storage capacity.At this juncture,integrating the merits of cloud computing and edge computing during the process of rationalizing the data placement of scientific workflows and optimizing the energy and time incurred in data transmission across different datacentres remains a challenge.In this paper,Adaptive Cooperative Foraging and Dispersed Foraging Strategies-Improved Harris Hawks Optimization Algorithm(ACF-DFS-HHOA)is proposed for optimizing the energy and data transmission time in the event of placing data for a specific scientific workflow.This ACF-DFS-HHOA considered the factors influencing transmission delay and energy consumption of data centers into account during the process of rationalizing the data placement of scientific workflows.The adaptive cooperative and dispersed foraging strategy is included in HHOA to guide the position updates that improve population diversity and effectively prevent the algorithm from being trapped into local optimality points.The experimental results of ACF-DFS-HHOA confirmed its predominance in minimizing energy and data transmission time incurred during workflow execution. 展开更多
关键词 Edge computing cloud computing scientific workflow data placement energy of datacenters data transmission time
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Different percutaneous transhepatic biliary stent placements and catheter drainage in the treatment of middle and low malignant biliary obstruction
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作者 Yao-Bo Yang Zhao-Yong Yan +3 位作者 Yang Jiao Wei-Hao Yang Qi Cui Si-Pan Chen 《World Journal of Gastrointestinal Surgery》 SCIE 2023年第7期1397-1404,共8页
BACKGROUND For cases of middle and low biliary obstruction with left and right hepatic duct dilatation,the type of approach and whether different approaches affect the difficulty of puncture operation and intraoperati... BACKGROUND For cases of middle and low biliary obstruction with left and right hepatic duct dilatation,the type of approach and whether different approaches affect the difficulty of puncture operation and intraoperative and postoperative complications have not been discussed in detail.AIM To compare the efficacy of different percutaneous transhepatic biliary stent placements and catheter drainage in treating middle and low biliary obstruction.METHODS A retrospective analysis was performed on the medical records of 424 patients with middle and low biliary obstruction who underwent percutaneous liver puncture biliary stent placement and catheter drainage at the Department of Interventional Radiology,Shaanxi Provincial People’s Hospital between March 2016 and March 2022.Based on the puncture path,patients were categorized into two groups:Subxiphoid left hepatic lobe approach group(Group A,224 cases)and right intercostal,right hepatic lobe approach group(Group B,200 cases).Liver function improvement,postoperative biliary bleeding incidence,postoperative pain duration,and abdominal effusion leakage around the drainage tube were compared between the two groups at 3 d and 1 wk after the surgery.Patient survival time was recorded during follow-up.RESULTS All 424 surgeries were successful without adverse events.Group A comprised 224 cases,and Group B had 200 cases.There was no statistically significant difference in basic data between Group A and Group B(P>0.05).No significant difference in postoperative biliary bleeding incidence was observed between the groups(P>0.05).The decreased rates for total bilirubin(Group A:69.23±4.50,Group B:63.79±5.65),direct bilirubin(Group A:79.30±11.19,Group B:63.62±5.64),and alkaline phosphatase(Group A:60.51±12.23,Group B:42.68±23.56)in the 1st wk after surgery were significantly faster in Group A than in Group B.The decreased rate of gamma-glutamyl transpeptidase was also significantly faster in Group A at both 3 d(Group A:40.56±10.32,Group B:32.22±5.12)and 1 wk(Group A:73.19±7.05,Group B:58.81±18.98)after surgery(P<0.05).Group A experienced significantly less peritoneal effusion leakage around the drainage tube than Group B(P<0.05).The patient survival rate was higher in Group A compared to Group B(P<0.05).CONCLUSION In treating jaundice patients with middle and low biliary obstruction,a percutaneous left liver puncture demonstrated better clinical efficacy than a percutaneous right liver puncture. 展开更多
关键词 Biliary obstruction Puncture route Stent placement Survival rate Malignant tumor Digestive tract
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Ruppert's Delaunay Triangulation Refinement Scheme for Optimal RSUs Placement in Vehicle to Infrastructure Communication Network
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作者 Selvakumari P Chinnasamy A +1 位作者 Sree Rathna Lakshmi NVS Sheela D 《China Communications》 SCIE CSCD 2023年第7期303-320,共18页
Road Side Units(RSUs)are the essential component of vehicular communication for the objective of improving safety and mobility in the road transportation.RSUs are generally deployed at the roadside and more specifical... Road Side Units(RSUs)are the essential component of vehicular communication for the objective of improving safety and mobility in the road transportation.RSUs are generally deployed at the roadside and more specifically at the intersections in order to collect traffic information from the vehicles and disseminate alarms and messages in emergency situations to the neighborhood vehicles cooperating with the network.However,the development of a predominant RSUs placement algorithm for ensuring competent communication in VANETs is a challenging issue due to the hindrance of obstacles like water bodies,trees and buildings.In this paper,Ruppert’s Delaunay Triangulation Refinement Scheme(RDTRS)for optimal RSUs placement is proposed for accurately estimating the optimal number of RSUs that has the possibility of enhancing the area of coverage during data communication.This RDTRS is proposed by considering the maximum number of factors such as global coverage,intersection popularity,vehicle density and obstacles present in the map for optimal RSUs placement,which is considered as the core improvement over the existing RSUs optimal placement strategies.It is contributed for deploying requisite RSUs with essential transmission range for maximal coverage in the convex map such that each position of the map could be effectively covered by at least one RSU in the presence of obstacles.The simulation experiments of the proposed RDTRS are conducted with complex road traffic environments.The results of this proposed RDTRS confirmed its predominance in reducing the end-to-end delay by 21.32%,packet loss by 9.38%with improved packet delivery rate of 10.68%,compared to the benchmarked schemes. 展开更多
关键词 road side units(RSUs) ruppert’s delau-nay triangulation refinement area of global coverage optimal RSUs placement
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Optimal Placement and Sizing of Distributed Generations for Power Losses Minimization Using PSO-Based Deep Learning Techniques
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作者 Bello-Pierre Ngoussandou Nicodem Nisso +1 位作者 Dieudonné Kaoga Kidmo   Kitmo 《Smart Grid and Renewable Energy》 2023年第9期169-181,共13页
The integration of distributed generations (DGs) into distribution systems (DSs) is increasingly becoming a solution for compensating for isolated local energy systems (ILESs). Additionally, distributed generations ar... The integration of distributed generations (DGs) into distribution systems (DSs) is increasingly becoming a solution for compensating for isolated local energy systems (ILESs). Additionally, distributed generations are used for self-consumption with excess energy injected into centralized grids (CGs). However, the improper sizing of renewable energy systems (RESs) exposes the entire system to power losses. This work presents an optimization of a system consisting of distributed generations. Firstly, PSO algorithms evaluate the size of the entire system on the IEEE bus 14 test standard. Secondly, the size of the system is allocated using improved Particles Swarm Optimization (IPSO). The convergence speed of the objective function enables a conjecture to be made about the robustness of the proposed system. The power and voltage profile on the IEEE 14-bus standard displays a decrease in power losses and an appropriate response to energy demands (EDs), validating the proposed method. 展开更多
关键词 Distributed Generations Deep Learning Techniques Improved Particle Swarm Optimization Power Losses Power Losses Minimization Optimal placement
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Controller Placement in Software Defined Internet of Things Using Optimization Algorithm
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作者 Sikander Hans Smarajit Ghosh +2 位作者 Aman Kataria Vinod Karar Sarika Sharma 《Computers, Materials & Continua》 SCIE EI 2022年第3期5073-5089,共17页
The current and future status of the internet is represented by the upcoming Internet of Things(IoT).The internet can connect the huge amount of data,which contains lot of processing operations and efforts to transfer... The current and future status of the internet is represented by the upcoming Internet of Things(IoT).The internet can connect the huge amount of data,which contains lot of processing operations and efforts to transfer the pieces of information.The emerging IoT technology in which the smart ecosystem is enabled by the physical object fixed with software electronics,sensors and network connectivity.Nowadays,there are two trending technologies that take the platform i.e.,Software Defined Network(SDN)and IoT(SD-IoT).The main aim of the IoT network is to connect and organize different objects with the internet,which is managed with the control panel and data panel in the SD network.The main issue and the challenging factors in this network are the increase in the delay and latency problem between the controllers.It is more significant for wide area networks,because of the large packet propagation latency and the controller placement problem is more important in every network.In the proposed work,IoT is implementing with adaptive fuzzy controller placement using the enhanced sunflower optimization(ESFO)algorithm and Pareto Optimal Controller placement tool(POCO)for the placement problem of the controller.In order to prove the efficiency of the proposed system,it is compared with other existing methods like PASIN,hybrid SD and PSO in terms of load balance,reduced number of controllers and average latency and delay.With 2 controllers,the proposed method obtains 400 miles as average latency,which is 22.2%smaller than PSO,76.9%lesser than hybrid SD and 91.89%lesser than PASIN. 展开更多
关键词 SD-IoT adaptive fuzzy controller enhanced sunflower optimization(ESFO) POCO placement tool controller placement problem and minimum latency
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A new free-hand pedicle screw placement technique with reference to the supraspinal ligament 被引量:7
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作者 Juming Li Hong Zhao +7 位作者 Hao Xie Lipeng Yu Jifu Wei Min Zong Feng Chen Ziqiang Zhu Ning Zhang Xiaojian Cao 《The Journal of Biomedical Research》 CAS 2014年第1期64-70,共7页
We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the t... We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the tho- racic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the corresponding supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative ra- diographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conven- tional technique group was 96.3% and 94.2% (P 〈 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P 〈 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during op- eration (P 〉 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lum- bar spine. 展开更多
关键词 spine fracture pedicle screw placement radiation exposure supraspinal ligament anatomy reference
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Optimum placement and characteristics of velocity-dependent dampers under seismic excitation 被引量:3
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作者 Seyed Amin Mousavi Amir K.Ghorbani-Tanha 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2012年第3期403-414,共12页
In this study, through novel drift-based equations of motion in the frequency domain, optimum placement and characteristics of linear velocity-dependent dampers are investigated. In this study, the sum of the square o... In this study, through novel drift-based equations of motion in the frequency domain, optimum placement and characteristics of linear velocity-dependent dampers are investigated. In this study, the sum of the square of the absolute values of transfer matrix elements for interstory drifts is considered as the optimization index. Optimum placement and characteristics of dampers are simultaneously obtained by minimizing the optimization index through an incremental procedure. In each step of the procedure, a predefined value is considered as the damper characteristic. The optimum story for this increment is selected such that it leads to a minimum value for the optimization index. The procedure is repeated for the next increments until the optimization index meets its target value, which is obtained according to the desired damping ratio for the overall structure. In other words, the desired overall damping ratio is the input to the proposed procedure, and the optimal placement and characteristics of the dampers are its output. It is observed that the optimal placement of a velocitydependent damper depends on the damping coefficient of the added damper, frequency of the excitation, and distribution of the mass, stiffness, and inherent damping of the main structure. 展开更多
关键词 passive control velocity-dependent damper optimum placement optimum damping transfer matrix storydamping coefficient
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Combined Use of Single-balloon Enteroscope and Colonoscope for Self-expandable Metal Stent Placement in Patients with Malignant Small Intestinal Obstruction: a Single-center Comparative Clinical Observation 被引量:3
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作者 张亚飞 宁守斌 +7 位作者 李白容 张静 李静 唐杰 朱鸣 金晓维 赵秋 毛高平 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2017年第3期357-361,共5页
Small intestinal obstruction is a common complication of primary gastrointestinal cancer or metastatic cancers. Patients with this condition are often poor candidates for surgical bypasses, and placement of self-expan... Small intestinal obstruction is a common complication of primary gastrointestinal cancer or metastatic cancers. Patients with this condition are often poor candidates for surgical bypasses, and placement of self-expanding metal stent(SEMS) can be technically challenging. In this study, we examined the feasibility of combined application of single-balloon enteroscope(SBE) and colonoscope for SEMS placement in patients with malignant small intestinal obstruction. Thirty-four patients were enrolled in this study, among which 22 patients received SEMS placement by using SBE and colonoscope, while the other 12 patients received conservative medical treatment. The patients were followed up for one year. Stent placement was technically feasible in 95.5%(21/22). Clinical improvement was achieved in 86.4%(19/22). For the 19 clinical success cases, the average time of benefits from a gastric outlet obstruction scoring system(GOOSS) increase ≥1 was 111.9±89.5 days. For the 12 patients receiving conservative medical treatment, no significant improvement in GOOSS score was observed. Moreover, a significant increase of Short-Form-36 health survey score was observed in the 19 patients at time of 30 days after stent placement. By Kaplan-Meier analysis, a significant survival improvement was observed in patients with successful SEMS placement, compared with patients receiving conservative medical treatment. Taken together, combined use of SBE and colonoscope makes endoscopic stent placement feasible in patients with malignant small intestinal obstruction, and patients can benefit from it in terms of prolonged survival and improved quality of life. 展开更多
关键词 small intestinal obstruction single-balloon enteroscope colonoscope stent placement
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Optimal sensor placement in hydropower house based on improved triaxial effective independence method 被引量:4
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作者 Ji-jian LIAN Long-jun HE Hai-jun WANG 《Water Science and Engineering》 EI CAS 2012年第3期329-339,共11页
The capacity and size of hydro-generator units are increasing with the rapid development of hydroelectric enterprises, and the vibration of the powerhouse structure has increasingly become a major problem. Field testi... The capacity and size of hydro-generator units are increasing with the rapid development of hydroelectric enterprises, and the vibration of the powerhouse structure has increasingly become a major problem. Field testing is an important method for research on dynamic identification and vibration mechanisms. Research on optimal sensor placement has become a very important topic due to the need to obtain effective testing information from limited test resources. To overcome inadequacies of the present methods, this paper puts forward the triaxial effective independence driving-point residue (EfI3-DPR3) method for optimal sensor placement. The Efl3-DPR3 method can incorporate both the maximum triaxial modal kinetic energy and linear independence of the triaxial target modes at the selected nodes. It was applied to the optimal placement oftriaxial sensors for vibration testing in a hydropower house, and satisfactory results were obtained. This method can provide some guidance for optimal placement of triaxial sensors of underground powerhouses. 展开更多
关键词 triaxial sensor optimal placement Efl3-DPR3 method hydropower house "vibration testing
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Pole placement method of controlling chaos in DC-DC buck converters 被引量:2
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作者 邹艳丽 罗晓曙 陈关荣 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第8期1719-1724,共6页
Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calc... Based on the mechanism for the generation of chaos in a buck converter, a pole placement method is proposed and applied to controlling the chaos in a circuit. The control circuit is designed and tested. Numerical calculation and circuit implementation demonstrate the validity of this chaos control method. 展开更多
关键词 buck converters CHAOS chaos control pole placement method
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А Novel AP Placement Algorithm Based on User Distribution for Indoor WLAN System 被引量:3
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作者 ShuTang Lin Ma Yubin Xu 《China Communications》 SCIE CSCD 2016年第10期108-118,共11页
AP deployment is significant for indoor WLAN system to achieve seamless coverage. The available algorithms do not take user distribution into consideration so that poor user coverage and imbalanced network load occur.... AP deployment is significant for indoor WLAN system to achieve seamless coverage. The available algorithms do not take user distribution into consideration so that poor user coverage and imbalanced network load occur. Therefore, this paper proposed a novel AP placement algorithm to bridge the AP deployment with user distribution. The proposed algorithm employs statistics theory to model the user distribution as its location and probability. Then we obtain the AP location based on the fuzzy C-clustering algorithm. The proposed algorithm is practical for implementation, which means the actual signal transmission isn't required in our proposed method. The simulation results show that the proposed algorithm could automatically achieve a good AP deployment with different user distribution, and provide a good performance in the maximum users and AP load balance in WLAN. 展开更多
关键词 AP placement user distribution fuzzy C-clustering artificial fish maximum users AP load balance
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Automated Controller Placement for Software-Defined Networks to Resist DDoS Attacks 被引量:4
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作者 Muhammad Reazul Haque Saw Chin Tan +8 位作者 Zulfadzli Yusoff Kashif Nisar Lee Ching Kwang Rizaludin Kaspin Bhawani Shankar Chowdhry Rajkumar Buyya Satya Prasad Majumder Manoj Gupta Shuaib Memon 《Computers, Materials & Continua》 SCIE EI 2021年第9期3147-3165,共19页
In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication systems.Existing research ha... In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication systems.Existing research has concentrated largely on factors such as reliability,latency,controller capacity,propagation delay,and energy consumption.However,SDNs are vulnerable to distributed denial of service(DDoS)attacks that interfere with legitimate use of the network.The ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design,especially in critical applications such as military,health care,and financial services networks requiring high availability.We propose a mathematical model for planning the deployment of SDN smart backup controllers(SBCs)to preserve service in the presence of DDoS attacks.Given a number of input parameters,our model has two distinct capabilities.First,it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating conditions.Second,it recommends an optimal number of smart backup controllers for use with different levels of DDoS attacks.The goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the parameters.Our simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost. 展开更多
关键词 SDN automated controller placement SBC ILP DDoS attack
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Nitrogen Deep Placement Combined with Straw Mulch Cultivation Enhances Physiological Traits,Grain Yield and Nitrogen Use Efficiency in Mechanical Pot-Seedling Transplanting Rice 被引量:6
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作者 LI Lin ZHANG Zheng +7 位作者 TIAN Hua Umair ASHRAF Yousef Alhaj HAMOUD Al Aasmi ALAA TANG Xiangru DUAN Meiyang WANG Zaiman PAN Shenggang 《Rice science》 SCIE CSCD 2022年第1期89-100,I0031,共13页
To assess the effects of straw return coupled with deep nitrogen(N)fertilization on grain yield and N use efficiency(NUE)in mechanical pot-seedling transplanting(MPST)rice,the seedlings of two rice cultivars,i.e.,Yuxi... To assess the effects of straw return coupled with deep nitrogen(N)fertilization on grain yield and N use efficiency(NUE)in mechanical pot-seedling transplanting(MPST)rice,the seedlings of two rice cultivars,i.e.,Yuxiangyouzhan and Wufengyou 615 transplanted by MPST were applied with N fertilizer at 150 kg/hm2 and straw return at 6 t/hm2 in early seasons of 2019 and 2020.The experiment comprised of following treatments:CK(no fertilizer and no straw return),MDS(deep N fertilization and straw return),MBS(broadcasting fertilizer and straw return),MD(deep N fertilization without straw return),MB(broadcasting fertilizer without straw return).Results depicted that the MDS treatment significantly increased the rice yield by 41.69%-72.22%due to total above-ground biomass,leaf area index and photosynthesis increased by 54.70%-55.80%,38.52%-52.17%and 17.89%-28.40%,respectively,compared to the MB treatment.In addition,the MDS treatment enhanced the total N accumulation by 37.74%-43.69%,N recovery efficiency by 141.45%-164.65%,N agronomic efficiency by 121.76%-134.19%,nitrate reductase by 46.46%-60.86%and glutamine synthetase by 23.56%-31.02%,compared to the MB treatment.The average grain yield and NUE in both years for Yuxiangyouzhan were higher in the MDS treatment than in the MD treatment.Hence,deep N fertilization combined with straw return can be an innovative technique with improved grain yield and NUE in MPST in South China. 展开更多
关键词 mechanical pot-seedling transplanting nitrogen deep placement nitrogen use efficiency RICE straw return
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