Placement optimization is a crucial phase in chip design,involving the strategic arrangement of cells within a limited region to enhance space utilization and reduce wirelength.Chip design enterprises need to optimize...Placement optimization is a crucial phase in chip design,involving the strategic arrangement of cells within a limited region to enhance space utilization and reduce wirelength.Chip design enterprises need to optimize the placement according to design rules to meet customer demands.While mixed-cell-height circuits are widely used in modern chip design,few studies have simultaneously considered the non-overlapping cells,rails alignment,and minimum implantation area constraints in the placement optimization problems.Hence,this study involves preprocessing the non-linear parts and developing a mixed-integer linear programming model to reduce the cost of legalizing chip placements for businesses.Furthermore,this study designs and implements an exact algorithm based on Benders decomposition,utilizing dual theory to obtain an optimal cut and iteratively solve for the coordinates of cells.Numerical experiments across various scales validate the performance of the algorithm.Through a detailed analysis of the shape of the chip region division,the proportion of different types of cells,the total number of cells and bins,and their impact on the placement,we derive some potentially useful design insights that can benefit chip design enterprises.展开更多
The increase in bridge structure span and the complex stress characteristics directly affect the optimization of sensor placement,which in turn influences the data acquisition performance of the monitoring system.The ...The increase in bridge structure span and the complex stress characteristics directly affect the optimization of sensor placement,which in turn influences the data acquisition performance of the monitoring system.The key to the information acquisition of a bridge monitoring system is to obtain data that meets the health monitoring requirements of the bridge with a limited number of measurement points.To address this,a hybrid method based on multiple optimization criteria is proposed for optimal sensor placement(OSP).First,the minimum number of modes required for bridge monitoring is determined using the information entropy criterion(IE).Then,the number of measurement points is determined using a sequence method combined with the modal assurance criterion(MAC).Finally,the sensor placement is optimized using the generalized genetic algorithm(GGA)combined with double-structure encoding,and the optimization results are validated through finite element model analysis.The research results show that the hybrid method based on multiple optimization criteria can effectively determine the number of measurement points for bridge structures and optimize sensor placement,with a significant improvement in computational speed.展开更多
Breast augmentation with implants is a popular cosmetic surgery that enhances breast volume and contour through various placement planes.In this review,we examine the impact of subglandular,subpectoral,and subfascial ...Breast augmentation with implants is a popular cosmetic surgery that enhances breast volume and contour through various placement planes.In this review,we examine the impact of subglandular,subpectoral,and subfascial implant planes on postoperative outcomes and complication rates.Subglandular placement offers simplicity but is associated with higher risks of capsular contracture,hematoma,and rippling in patients with low tissue coverage.The subpectoral plane,widely adopted for its natural appearance and reduced capsular contracture risk,may cause dynamic deformity due to muscle contraction.Although technically challenging,the subfascial plane combines the benefits of soft tissue support and reduced implant displacement.We highlight the importance of choosing an optimal implant plane tailored to each patient’s anatomical and aesthetic needs to enhance surgical outcomes and minimize complications.Further research is needed to validate long-term efficacy,particularly for subfascial placement.展开更多
In pedicle screw fixation,surgical robot and preoperative planning are enabling technologies to improve the accuracy and safety of pedicle screw placement.In this study,an automatic segmentation method for the pedicle...In pedicle screw fixation,surgical robot and preoperative planning are enabling technologies to improve the accuracy and safety of pedicle screw placement.In this study,an automatic segmentation method for the pedicle and vertebral body is proposed based on the 3D anatomical features of vertebrae.Further,an optimal insertion path is obtained to balance the safety of pedicle screw placement and the vertebral-screw interface strength.The pedicle screw radius is then determined based on the pedicle radius.A classification method is proposed to assess the accuracy of path planning.Finally,the surgical robot’s path can be updated based on the actual positions of the surgical robot and the patient.The CT data of 12 human vertebrae(T6−L5),10 porcine vertebrae(L1−L5)and 5 ovine vertebrae(L1−L5)are used to validate the effectiveness of the proposed method.All pedicle screw placement paths are successfully generated,achieving an excellence or good rate of 98%.Ex vivo pedicle screw placement experiments are conducted on human spine phantom,porcine and ovine spines,and in vivo experiment is conducted on a Bama miniature pig.In the proposed method,both safety and accuracy of pedicle screw placement are improved.According to the widely recognized Gertzbein-Robbins classification,93.18%of the outcomes achieve Grade A,showing promising potential in clinics.展开更多
Inflatable penile prosthesis(IPP)implantation is the gold standard treatment for patients with erectile dysfunction who are refractory to medical therapy.The standard placement of the reservoir in the space of Retzius...Inflatable penile prosthesis(IPP)implantation is the gold standard treatment for patients with erectile dysfunction who are refractory to medical therapy.The standard placement of the reservoir in the space of Retzius(SOR)may be contraindicated in patients with prior pelvic or abdominal surgery due to altered anatomy and increased risk of complications.This has led to the development of alternative ectopic reservoir placement techniques.In this narrative review,we summarize the literature on various ectopic reservoir approaches,including low and high submuscular placements,submuscular techniques with counter incisions or transfascial fixation,midline submuscular placement,subcutaneous placement,and lateral retroperitoneal approaches.We describe the surgical methods,outcomes,and complication rates associated with each technique.While most methods demonstrate low complication and revision rates,direct comparisons remain limited due to heterogeneity and lack of prospective data.This review highlights the importance of individualized technique selection based on prior surgical history,body habitus,and surgeon experience.As ectopic placement becomes more widely adopted,familiarity with multiple approaches is essential for prosthetic surgeons.展开更多
This study aimed to explore an effective nursing plan for peripherally inserted central catheter(PICC)placement guided by endocardial electrocardiogram(ECG)positioning technology and to analyze related nursing problem...This study aimed to explore an effective nursing plan for peripherally inserted central catheter(PICC)placement guided by endocardial electrocardiogram(ECG)positioning technology and to analyze related nursing problems and countermeasures.A total of 96 patients who underwent PICC placement using ECG-guided positioning technology in our hospital from January 2024 to December 2024 were selected and randomly divided into an experimental group(n=48)and a control group(n=48)using a random number table.The control group received routine basic nursing care,while the experimental group was provided with comprehensive high-quality nursing care.The results showed that the success rate of one-time catheter placement was significantly higher in the experimental group than in the control group(P<0.05),while the incidence of complications was notably lower in the experimental group(P<0.05).These findings suggest that comprehensive high-quality nursing care during PICC placement guided by ECG positioning technology can effectively enhance the success rate of catheter placement and reduce complications,indicating that this nursing approach is valuable for clinical promotion and application.展开更多
BACKGROUND Both stent placement and endoscopic nasobiliary drainage(ENBD)are commonly used for treating bile leakage following liver transplantation.However,little research has compared the advantages of both methods....BACKGROUND Both stent placement and endoscopic nasobiliary drainage(ENBD)are commonly used for treating bile leakage following liver transplantation.However,little research has compared the advantages of both methods.AIM To compare the prognosis of stent placement and ENBD in treating bile leakage following liver transplantation.METHODS We retrospectively collected data for patients with bile leakage after liver tran-splantation in our center.The efficiency and prognosis were compared between the stent placement and ENBD groups.RESULTS We retrospectively collected data from 50 patients diagnosed with bile leakage within 1 month after liver transplantation.Forty patients underwent ENBD and nine received stent placement.Baseline patient characteristics,except white blood cell count,total bilirubin and direct bilirubin levels,were comparable between the two groups.Additionally,there was no significant difference in the rates of re-conveyance or postoperative biliary stricture.CONCLUSION Stent placement and ENBD are recommended for treating bile leakage after liver transplantation,with similar efficacy and prognosis.展开更多
The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers wer...The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.展开更多
To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installa...To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installation location greatly impact the whole network.For the traditional DAP placement algorithm,the number of DAPs must be set in advance,but determining the best number of DAPs is difficult,which undoubtedly reduces the overall performance of the network.Moreover,the excessive gap between the loads of different DAPs is also an important factor affecting the quality of the network.To address the above problems,this paper proposes a DAP placement algorithm,APSSA,based on the improved affinity propagation(AP)algorithm and sparrow search(SSA)algorithm,which can select the appropriate number of DAPs to be installed and the corresponding installation locations according to the number of SMs and their distribution locations in different environments.The algorithm adds an allocation mechanism to optimize the subnetwork in the SSA.APSSA is evaluated under three different areas and compared with other DAP placement algorithms.The experimental results validated that the method in this paper can reduce the network cost,shorten the average transmission distance,and reduce the load gap.展开更多
Metadata prefetching and data placement play a critical role in enhancing access performance for file systems operating over wide-area networks.However,developing effective strategies for metadata prefetching in envir...Metadata prefetching and data placement play a critical role in enhancing access performance for file systems operating over wide-area networks.However,developing effective strategies for metadata prefetching in environments with concurrent workloads and for data placement across distributed networks remains a significant challenge.This study introduces novel and efficient methodologies for metadata prefetching and data placement,leveraging fine-grained control of prefetching strategies and variable-sized data fragment writing to optimize the I/O bandwidth of distributed file systems.The proposed metadata prefetching technique employs dynamic workload analysis to identify dominant workload patterns and adaptively refines prefetching policies,thereby boosting metadata access efficiency under concurrent scenarios.Meanwhile,the data placement strategy improves write performance by storing data fragments locally within the nearest data center and transmitting only the fragment location metadata to the remote data center hosting the original file.Experimental evaluations using real-world system traces demonstrate that the proposed approaches reduce metadata access times by up to 33.5%and application data access times by 17.19%compared to state-of-the-art techniques.展开更多
Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency...Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency and serious environmental pollution.Deep placement of nitrogen fertilizer(DPNF)is an agronomic measure that shows promise in addressing these issues.This review aims to offer a comprehensive understanding of DPNF,beginning with a succinct overview of its development and methodologies for implementation.Subsequently,the optimal fertilization depth and influencing factors for different crops are analyzed and discussed.Additionally,it investigates the regulation and mechanism underlying the DPNF on crop development,yield,N use efficiency and greenhouse gas emissions.Finally,the review delineates the limitations and challenges of this technology and provides suggestions for its improvement and application.This review provides valuable insight and reference for the promotion and adoption of DPNF in agricultural practice.展开更多
Conventional optimal sensor placement(OSP)methods employ the premise that all sensors work perfectly during long-term structural monitoring.However,this premise is often difficult to fulfill in real applications due t...Conventional optimal sensor placement(OSP)methods employ the premise that all sensors work perfectly during long-term structural monitoring.However,this premise is often difficult to fulfill in real applications due to poor manufacturing and material aging of sensors,human damage,and electromagnetic interference.This paper presents a robustness-oriented OSP method that considers sensor failures.The OSP problem is designed with consideration of sensor failures to ensure that both complete vibration data collected by all sensors and incomplete vibration data caused by individual sensor failures can accurately identify structural modal parameters.A dispersion-aggregation firefly algorithm(DAFA),which is derived from the basic firefly algorithm,has been proposed to solve this complicated optimization problem.The dispersion and aggregation operators are designed to prevent falling into local optima and to rapidly converge to the global optima.The proposed methodology is confirmed by extracting the robust sensor configuration for a long-span cable-stayed bridge.The robustness of the optimal sensor configurations against sensor failure is thoroughly explored,and the performance of the proposed DAFA is extensively examined.展开更多
BACKGROUND Ultrasound-guided peripherally inserted central catheter(PICC)placement is vital for cancer therapy,but lidocaine infiltration faces limitations like puncture pain and vasospasm.AIM To assess the clinical e...BACKGROUND Ultrasound-guided peripherally inserted central catheter(PICC)placement is vital for cancer therapy,but lidocaine infiltration faces limitations like puncture pain and vasospasm.AIM To assess the clinical efficacy of a no-pain intervention-combining compound lidocaine cream with warm compress-in reducing pain during ultrasound-guided PICC placement in cancer patients.METHODS A retrospective cohort study analyzed 88 cancer patients undergoing PICC placement(Shanghai Fourth People’s Hospital,2024).Patients were divided into control(lidocaine infiltration,n=44)and intervention(cream+warm compress,n=44)groups.Primary outcomes:Pain scores(numerical rating scale),procedural time,complications;secondary outcome:Satisfaction.RESULTS The intervention group showed significantly lower pain scores(1.2±0.4 vs 3.8±1.2,P=0.012)with comparable first-attempt success(95.5%vs 90.9%)and safety(P=0.672).Thermal activation of transient receptor potential vanilloid 1 channel enhanced drug penetration,achieving anesthesia within 8-10 minutes.Patient satisfaction reached 97.7%.CONCLUSION The combination of compound lidocaine cream with warm compress significantly alleviates procedural pain and enhances patient satisfaction during ultrasound-guided PICC placement in cancer patients,supporting its clinical application.展开更多
Dear Editor,We present a modified surgical technique to verify the chorion layer of the human amniotic membrane(hAM)in treating retinal detachment(RD)with vitrectomy.RD patients with pathological myopia where the tear...Dear Editor,We present a modified surgical technique to verify the chorion layer of the human amniotic membrane(hAM)in treating retinal detachment(RD)with vitrectomy.RD patients with pathological myopia where the tear is located within the posterior pole choroidal atrophy area are difficult to treat.Surgical procedures such as laser treatments,diathermy,cryopexy applications or long-term silicone oil endotamponade may not only be ineffective but also harmful in these cases^([1]).Amniotic membrane transplantation(AMT)is an effective technique in case of RD recurrences to seal retinal holes over high myopic chorioretinal atrophy^([2]).展开更多
During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is spr...During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is sprayed manually.Furthermore,it can also affect the permeability of the preform,resin injection and the quality of the vacuum assisted resin infusion(VARI)molding,resulting in a decrease in the mechanical properties of composite materials.This study utilizes dry fiber automated placement equipment and an automated spraying system to manufacture preform structures,followed by VARI process to prepare composite samples with varying setting agent contents.Subsequently,mechanical characterization including interlaminar shear,bending and tensile testing is conducted to investigate the influence of setting agent content on both the manufacturing process and the mechanical properties of composite products.The results show that the interlaminar shear strength,bending strength and tensile strength of the sample gradually decrease with the increase of the content of the setting agent.The optimal setting agent content for automated laying of dry fiber is determined to be 4%-6%,balancing the preformed body’s layup quality and its impact on mechanical properties.Compared with agent-free samples,this range results in reductions of 3% in interlaminar shear strength,9% in bending strength,11% in bending modulus,and 13%-16% in tensile strength.展开更多
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
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
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
The controller is a main component in the Software-Defined Networking(SDN)framework,which plays a significant role in enabling programmability and orchestration for 5G and next-generation networks.In SDN,frequent comm...The controller is a main component in the Software-Defined Networking(SDN)framework,which plays a significant role in enabling programmability and orchestration for 5G and next-generation networks.In SDN,frequent communication occurs between network switches and the controller,which manages and directs traffic flows.If the controller is not strategically placed within the network,this communication can experience increased delays,negatively affecting network performance.Specifically,an improperly placed controller can lead to higher end-to-end(E2E)delay,as switches must traverse more hops or encounter greater propagation delays when communicating with the controller.This paper introduces a novel approach using Deep Q-Learning(DQL)to dynamically place controllers in Software-Defined Internet of Things(SD-IoT)environments,with the goal of minimizing E2E delay between switches and controllers.E2E delay,a crucial metric for network performance,is influenced by two key factors:hop count,which measures the number of network nodes data must traverse,and propagation delay,which accounts for the physical distance between nodes.Our approach models the controller placement problem as a Markov Decision Process(MDP).In this model,the network configuration at any given time is represented as a“state,”while“actions”correspond to potential decisions regarding the placement of controllers or the reassignment of switches to controllers.Using a Deep Q-Network(DQN)to approximate the Q-function,the system learns the optimal controller placement by maximizing the cumulative reward,which is defined as the negative of the E2E delay.Essentially,the lower the delay,the higher the reward the system receives,enabling it to continuously improve its controller placement strategy.The experimental results show that our DQL-based method significantly reduces E2E delay when compared to traditional benchmark placement strategies.By dynamically learning from the network’s real-time conditions,the proposed method ensures that controller placement remains efficient and responsive,reducing communication delays and enhancing overall network performance.展开更多
Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on...Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on the inner edge of the tow placed along the curved trajectory,the resulting defects represented by buckling and wrinkles in spatial tow steering can induce poor manufacturing accuracy and quality degradation of products.In this paper,a theoretical model of tow buckling based on the first-order shear deformation laminate theory,linear elastic adhesion interface and Hertz compaction contact theory is proposed to analyze the formation mechanism of the wrinkles and predict the formation of defects by solving the critical radius of the trajectory,and finite element analysis involving the cohesive zone modeling(CZM)is innovated to simulate the local buckling state of the steered tow in AFP.Additionally,numerical parametric studies and experimental results indicate that mechanical properties and geometric parameters of the prepreg,the curvature of the placement trajectory and critical process parameters have a significant impact on buckling formation,and optimization of process parameters can achieve effective suppression of placement defects.This research proposes a theoretical modeling method for tow buckling,and conducts in-depth research on defect formation and suppression methods based on finite element simulation and placement experiments.展开更多
基金supported by the National Natural Science Foundation of China(72025103,72394360,72394362,and 72361137001)the Project of Science and Technology Commission of Shanghai Municipality,China(23JC1402200).
文摘Placement optimization is a crucial phase in chip design,involving the strategic arrangement of cells within a limited region to enhance space utilization and reduce wirelength.Chip design enterprises need to optimize the placement according to design rules to meet customer demands.While mixed-cell-height circuits are widely used in modern chip design,few studies have simultaneously considered the non-overlapping cells,rails alignment,and minimum implantation area constraints in the placement optimization problems.Hence,this study involves preprocessing the non-linear parts and developing a mixed-integer linear programming model to reduce the cost of legalizing chip placements for businesses.Furthermore,this study designs and implements an exact algorithm based on Benders decomposition,utilizing dual theory to obtain an optimal cut and iteratively solve for the coordinates of cells.Numerical experiments across various scales validate the performance of the algorithm.Through a detailed analysis of the shape of the chip region division,the proportion of different types of cells,the total number of cells and bins,and their impact on the placement,we derive some potentially useful design insights that can benefit chip design enterprises.
文摘The increase in bridge structure span and the complex stress characteristics directly affect the optimization of sensor placement,which in turn influences the data acquisition performance of the monitoring system.The key to the information acquisition of a bridge monitoring system is to obtain data that meets the health monitoring requirements of the bridge with a limited number of measurement points.To address this,a hybrid method based on multiple optimization criteria is proposed for optimal sensor placement(OSP).First,the minimum number of modes required for bridge monitoring is determined using the information entropy criterion(IE).Then,the number of measurement points is determined using a sequence method combined with the modal assurance criterion(MAC).Finally,the sensor placement is optimized using the generalized genetic algorithm(GGA)combined with double-structure encoding,and the optimization results are validated through finite element model analysis.The research results show that the hybrid method based on multiple optimization criteria can effectively determine the number of measurement points for bridge structures and optimize sensor placement,with a significant improvement in computational speed.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(grant no.LQ22H150005).
文摘Breast augmentation with implants is a popular cosmetic surgery that enhances breast volume and contour through various placement planes.In this review,we examine the impact of subglandular,subpectoral,and subfascial implant planes on postoperative outcomes and complication rates.Subglandular placement offers simplicity but is associated with higher risks of capsular contracture,hematoma,and rippling in patients with low tissue coverage.The subpectoral plane,widely adopted for its natural appearance and reduced capsular contracture risk,may cause dynamic deformity due to muscle contraction.Although technically challenging,the subfascial plane combines the benefits of soft tissue support and reduced implant displacement.We highlight the importance of choosing an optimal implant plane tailored to each patient’s anatomical and aesthetic needs to enhance surgical outcomes and minimize complications.Further research is needed to validate long-term efficacy,particularly for subfascial placement.
基金Supported by Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011897)Shenzhen Science and Technology Program(Grant No.KQTD20210811090143060)+1 种基金Sustainable Development Science and Technology Special Project of Shenzhen(Grant No.KCXFZ20230731100900002)Tianjin Municipal Science and Technology Program(Grant No.22JCYBJC01240).
文摘In pedicle screw fixation,surgical robot and preoperative planning are enabling technologies to improve the accuracy and safety of pedicle screw placement.In this study,an automatic segmentation method for the pedicle and vertebral body is proposed based on the 3D anatomical features of vertebrae.Further,an optimal insertion path is obtained to balance the safety of pedicle screw placement and the vertebral-screw interface strength.The pedicle screw radius is then determined based on the pedicle radius.A classification method is proposed to assess the accuracy of path planning.Finally,the surgical robot’s path can be updated based on the actual positions of the surgical robot and the patient.The CT data of 12 human vertebrae(T6−L5),10 porcine vertebrae(L1−L5)and 5 ovine vertebrae(L1−L5)are used to validate the effectiveness of the proposed method.All pedicle screw placement paths are successfully generated,achieving an excellence or good rate of 98%.Ex vivo pedicle screw placement experiments are conducted on human spine phantom,porcine and ovine spines,and in vivo experiment is conducted on a Bama miniature pig.In the proposed method,both safety and accuracy of pedicle screw placement are improved.According to the widely recognized Gertzbein-Robbins classification,93.18%of the outcomes achieve Grade A,showing promising potential in clinics.
文摘Inflatable penile prosthesis(IPP)implantation is the gold standard treatment for patients with erectile dysfunction who are refractory to medical therapy.The standard placement of the reservoir in the space of Retzius(SOR)may be contraindicated in patients with prior pelvic or abdominal surgery due to altered anatomy and increased risk of complications.This has led to the development of alternative ectopic reservoir placement techniques.In this narrative review,we summarize the literature on various ectopic reservoir approaches,including low and high submuscular placements,submuscular techniques with counter incisions or transfascial fixation,midline submuscular placement,subcutaneous placement,and lateral retroperitoneal approaches.We describe the surgical methods,outcomes,and complication rates associated with each technique.While most methods demonstrate low complication and revision rates,direct comparisons remain limited due to heterogeneity and lack of prospective data.This review highlights the importance of individualized technique selection based on prior surgical history,body habitus,and surgeon experience.As ectopic placement becomes more widely adopted,familiarity with multiple approaches is essential for prosthetic surgeons.
文摘This study aimed to explore an effective nursing plan for peripherally inserted central catheter(PICC)placement guided by endocardial electrocardiogram(ECG)positioning technology and to analyze related nursing problems and countermeasures.A total of 96 patients who underwent PICC placement using ECG-guided positioning technology in our hospital from January 2024 to December 2024 were selected and randomly divided into an experimental group(n=48)and a control group(n=48)using a random number table.The control group received routine basic nursing care,while the experimental group was provided with comprehensive high-quality nursing care.The results showed that the success rate of one-time catheter placement was significantly higher in the experimental group than in the control group(P<0.05),while the incidence of complications was notably lower in the experimental group(P<0.05).These findings suggest that comprehensive high-quality nursing care during PICC placement guided by ECG positioning technology can effectively enhance the success rate of catheter placement and reduce complications,indicating that this nursing approach is valuable for clinical promotion and application.
文摘BACKGROUND Both stent placement and endoscopic nasobiliary drainage(ENBD)are commonly used for treating bile leakage following liver transplantation.However,little research has compared the advantages of both methods.AIM To compare the prognosis of stent placement and ENBD in treating bile leakage following liver transplantation.METHODS We retrospectively collected data for patients with bile leakage after liver tran-splantation in our center.The efficiency and prognosis were compared between the stent placement and ENBD groups.RESULTS We retrospectively collected data from 50 patients diagnosed with bile leakage within 1 month after liver transplantation.Forty patients underwent ENBD and nine received stent placement.Baseline patient characteristics,except white blood cell count,total bilirubin and direct bilirubin levels,were comparable between the two groups.Additionally,there was no significant difference in the rates of re-conveyance or postoperative biliary stricture.CONCLUSION Stent placement and ENBD are recommended for treating bile leakage after liver transplantation,with similar efficacy and prognosis.
基金the National Natural Science Foundation of China(No.11502146)the 1 Batch of 2021 MOE of PRC Industry University Collaborative Education Program(No.202101042008)。
文摘The aim of this study was to assess the potential of surgical guides as a complementary tool to augmented reality(AR)in enhancing the safety and precision of pedicle screw placement in spinal surgery.Four trainers were divided into the AR navigation group using surgical guides and the free-hand group.Each group consisted of a novice and an experienced spine surgeon.A total of 80 pedicle screws were implanted.First,the AR group reconstructed the 3D model and planned the screw insertion route according to the computed tomography data of L2 lumbar vertebrae.Then,the Microsoft HoloLens™2 was used to identify the vertebral model,and the planned virtual path was superimposed on the real cone model.Next,the screw was placed according to the projected trajectory.Finally,Micron Tracker was used to measure the deviation of screws from the preoperatively planned trajectory,and pedicle screws were evaluated using the Gertzbein-Robbins scale.In the AR group,the linear deviations of the experienced doctor and the novice were(1.59±0.39)mm and(1.73±0.52)mm respectively,and the angle deviations were 2.72°±0.61°and 2.87°±0.63°respectively.In the free-hand group,the linear deviations of the experienced doctor and the novice were(2.88±0.58)mm and(5.25±0.62)mm respectively,and the angle deviations were 4.41°±1.18°and 7.15°±1.45°respectively.Both kinds of deviations between the two groups were significantly different(P<0.05).The screw accuracy rate was 95%in the AR navigation group and 77.5%in the free-hand group.The results of this study indicate that the integration of surgical guides and AR is an innovative technique that can substantially enhance the safety and precision of spinal surgery and assist inexperienced doctors in completing the surgery.
基金supported by the Fujian University of Technology under Grant GYZ20016,GY-Z18183,and GY-Z19005partially supported by the National Science and Technology Council under Grant NSTC 113-2221-E-224-056-.
文摘To transmit customer power data collected by smart meters(SMs)to utility companies,data must first be transmitted to the corresponding data aggregation point(DAP)of the SM.The number of DAPs installed and the installation location greatly impact the whole network.For the traditional DAP placement algorithm,the number of DAPs must be set in advance,but determining the best number of DAPs is difficult,which undoubtedly reduces the overall performance of the network.Moreover,the excessive gap between the loads of different DAPs is also an important factor affecting the quality of the network.To address the above problems,this paper proposes a DAP placement algorithm,APSSA,based on the improved affinity propagation(AP)algorithm and sparrow search(SSA)algorithm,which can select the appropriate number of DAPs to be installed and the corresponding installation locations according to the number of SMs and their distribution locations in different environments.The algorithm adds an allocation mechanism to optimize the subnetwork in the SSA.APSSA is evaluated under three different areas and compared with other DAP placement algorithms.The experimental results validated that the method in this paper can reduce the network cost,shorten the average transmission distance,and reduce the load gap.
基金funded by the National Natural Science Foundation of China under Grant No.62362019the Hainan Provincial Natural Science Foundation of China under Grant No.624RC482.
文摘Metadata prefetching and data placement play a critical role in enhancing access performance for file systems operating over wide-area networks.However,developing effective strategies for metadata prefetching in environments with concurrent workloads and for data placement across distributed networks remains a significant challenge.This study introduces novel and efficient methodologies for metadata prefetching and data placement,leveraging fine-grained control of prefetching strategies and variable-sized data fragment writing to optimize the I/O bandwidth of distributed file systems.The proposed metadata prefetching technique employs dynamic workload analysis to identify dominant workload patterns and adaptively refines prefetching policies,thereby boosting metadata access efficiency under concurrent scenarios.Meanwhile,the data placement strategy improves write performance by storing data fragments locally within the nearest data center and transmitting only the fragment location metadata to the remote data center hosting the original file.Experimental evaluations using real-world system traces demonstrate that the proposed approaches reduce metadata access times by up to 33.5%and application data access times by 17.19%compared to state-of-the-art techniques.
基金funded by grants from the National Natural Science Foundation of China(32301947,32272220 and 32172120)the China Postdoctoral Science Foundation(2023M730909).
文摘Nitrogen(N)serves as an essential nutrient for yield formation across diverse crop types.However,agricultural production encounters numerous challenges,notably high N fertilizer rates coupled with low N use efficiency and serious environmental pollution.Deep placement of nitrogen fertilizer(DPNF)is an agronomic measure that shows promise in addressing these issues.This review aims to offer a comprehensive understanding of DPNF,beginning with a succinct overview of its development and methodologies for implementation.Subsequently,the optimal fertilization depth and influencing factors for different crops are analyzed and discussed.Additionally,it investigates the regulation and mechanism underlying the DPNF on crop development,yield,N use efficiency and greenhouse gas emissions.Finally,the review delineates the limitations and challenges of this technology and provides suggestions for its improvement and application.This review provides valuable insight and reference for the promotion and adoption of DPNF in agricultural practice.
基金The National Natural Science Foundation of China(No.51978243,52578360).
文摘Conventional optimal sensor placement(OSP)methods employ the premise that all sensors work perfectly during long-term structural monitoring.However,this premise is often difficult to fulfill in real applications due to poor manufacturing and material aging of sensors,human damage,and electromagnetic interference.This paper presents a robustness-oriented OSP method that considers sensor failures.The OSP problem is designed with consideration of sensor failures to ensure that both complete vibration data collected by all sensors and incomplete vibration data caused by individual sensor failures can accurately identify structural modal parameters.A dispersion-aggregation firefly algorithm(DAFA),which is derived from the basic firefly algorithm,has been proposed to solve this complicated optimization problem.The dispersion and aggregation operators are designed to prevent falling into local optima and to rapidly converge to the global optima.The proposed methodology is confirmed by extracting the robust sensor configuration for a long-span cable-stayed bridge.The robustness of the optimal sensor configurations against sensor failure is thoroughly explored,and the performance of the proposed DAFA is extensively examined.
基金Supported by the Discipline Promotion Program of Shanghai Fourth People’s Hospital,No.SY-XKZT-2021-2006.
文摘BACKGROUND Ultrasound-guided peripherally inserted central catheter(PICC)placement is vital for cancer therapy,but lidocaine infiltration faces limitations like puncture pain and vasospasm.AIM To assess the clinical efficacy of a no-pain intervention-combining compound lidocaine cream with warm compress-in reducing pain during ultrasound-guided PICC placement in cancer patients.METHODS A retrospective cohort study analyzed 88 cancer patients undergoing PICC placement(Shanghai Fourth People’s Hospital,2024).Patients were divided into control(lidocaine infiltration,n=44)and intervention(cream+warm compress,n=44)groups.Primary outcomes:Pain scores(numerical rating scale),procedural time,complications;secondary outcome:Satisfaction.RESULTS The intervention group showed significantly lower pain scores(1.2±0.4 vs 3.8±1.2,P=0.012)with comparable first-attempt success(95.5%vs 90.9%)and safety(P=0.672).Thermal activation of transient receptor potential vanilloid 1 channel enhanced drug penetration,achieving anesthesia within 8-10 minutes.Patient satisfaction reached 97.7%.CONCLUSION The combination of compound lidocaine cream with warm compress significantly alleviates procedural pain and enhances patient satisfaction during ultrasound-guided PICC placement in cancer patients,supporting its clinical application.
文摘Dear Editor,We present a modified surgical technique to verify the chorion layer of the human amniotic membrane(hAM)in treating retinal detachment(RD)with vitrectomy.RD patients with pathological myopia where the tear is located within the posterior pole choroidal atrophy area are difficult to treat.Surgical procedures such as laser treatments,diathermy,cryopexy applications or long-term silicone oil endotamponade may not only be ineffective but also harmful in these cases^([1]).Amniotic membrane transplantation(AMT)is an effective technique in case of RD recurrences to seal retinal holes over high myopic chorioretinal atrophy^([2]).
基金supported by Jiangsu Provincial Key Research and Development Program(No.BE2023014-4).
文摘During the automated placement process of dry fibers,the positioning and fixation of dry fiber gauze belts are achieved by spraying setting agents.The amount of the setting agent is difficult to control when it is sprayed manually.Furthermore,it can also affect the permeability of the preform,resin injection and the quality of the vacuum assisted resin infusion(VARI)molding,resulting in a decrease in the mechanical properties of composite materials.This study utilizes dry fiber automated placement equipment and an automated spraying system to manufacture preform structures,followed by VARI process to prepare composite samples with varying setting agent contents.Subsequently,mechanical characterization including interlaminar shear,bending and tensile testing is conducted to investigate the influence of setting agent content on both the manufacturing process and the mechanical properties of composite products.The results show that the interlaminar shear strength,bending strength and tensile strength of the sample gradually decrease with the increase of the content of the setting agent.The optimal setting agent content for automated laying of dry fiber is determined to be 4%-6%,balancing the preformed body’s layup quality and its impact on mechanical properties.Compared with agent-free samples,this range results in reductions of 3% in interlaminar shear strength,9% in bending strength,11% in bending modulus,and 13%-16% in tensile strength.
基金Supported by National Key Research and Development Program of China(2022YFE0137200)Outstanding Youth Natural Science Fund of Shaanxi Province(2022JC-37)+2 种基金Innovation Capability Support Program of Shaanxi(2023-CX-TD-31)Natural Science Basic Research Project of Shaanxi Province(2024JC-YBQN-0381)National Natural Science Foundation of China(51874240,52204021)。
文摘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.
基金supported by National Natural Sciences Foundation of China(No.62271165,62027802,61831008)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030297,2021A1515011572)Shenzhen Science and Technology Program ZDSYS20210623091808025,Stable Support Plan Program GXWD20231129102638002.
文摘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.
基金supported via funding from Prince Sattam bin Abdulaziz University Project Number(PSAU/2024/R/1445).
文摘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.
基金supported by the Researcher Supporting Project number(RSPD2024R582),King Saud University,Riyadh,Saudi Arabia.
文摘The controller is a main component in the Software-Defined Networking(SDN)framework,which plays a significant role in enabling programmability and orchestration for 5G and next-generation networks.In SDN,frequent communication occurs between network switches and the controller,which manages and directs traffic flows.If the controller is not strategically placed within the network,this communication can experience increased delays,negatively affecting network performance.Specifically,an improperly placed controller can lead to higher end-to-end(E2E)delay,as switches must traverse more hops or encounter greater propagation delays when communicating with the controller.This paper introduces a novel approach using Deep Q-Learning(DQL)to dynamically place controllers in Software-Defined Internet of Things(SD-IoT)environments,with the goal of minimizing E2E delay between switches and controllers.E2E delay,a crucial metric for network performance,is influenced by two key factors:hop count,which measures the number of network nodes data must traverse,and propagation delay,which accounts for the physical distance between nodes.Our approach models the controller placement problem as a Markov Decision Process(MDP).In this model,the network configuration at any given time is represented as a“state,”while“actions”correspond to potential decisions regarding the placement of controllers or the reassignment of switches to controllers.Using a Deep Q-Network(DQN)to approximate the Q-function,the system learns the optimal controller placement by maximizing the cumulative reward,which is defined as the negative of the E2E delay.Essentially,the lower the delay,the higher the reward the system receives,enabling it to continuously improve its controller placement strategy.The experimental results show that our DQL-based method significantly reduces E2E delay when compared to traditional benchmark placement strategies.By dynamically learning from the network’s real-time conditions,the proposed method ensures that controller placement remains efficient and responsive,reducing communication delays and enhancing overall network performance.
基金Supported by National Natural Science Foundation of China(Grant Nos.52205003 and 51575018)Zhejiang Provincial Natural Science Foundation(Grant No.LD22E050011)Ningbo Municipal Key Projects of Science and Technology Innovation 2025 Plan(Grant No.2022Z070).
文摘Automated fiber placement(AFP)enables the efficient and precise fabrication of complex-shaped aerospace composite structures with lightweight and high-performance properties.However,due to the excessive compression on the inner edge of the tow placed along the curved trajectory,the resulting defects represented by buckling and wrinkles in spatial tow steering can induce poor manufacturing accuracy and quality degradation of products.In this paper,a theoretical model of tow buckling based on the first-order shear deformation laminate theory,linear elastic adhesion interface and Hertz compaction contact theory is proposed to analyze the formation mechanism of the wrinkles and predict the formation of defects by solving the critical radius of the trajectory,and finite element analysis involving the cohesive zone modeling(CZM)is innovated to simulate the local buckling state of the steered tow in AFP.Additionally,numerical parametric studies and experimental results indicate that mechanical properties and geometric parameters of the prepreg,the curvature of the placement trajectory and critical process parameters have a significant impact on buckling formation,and optimization of process parameters can achieve effective suppression of placement defects.This research proposes a theoretical modeling method for tow buckling,and conducts in-depth research on defect formation and suppression methods based on finite element simulation and placement experiments.
