期刊文献+
共找到2,693篇文章
< 1 2 135 >
每页显示 20 50 100
Dependence of Lower Molding Temperature Limit and Molding Time on Molding Mechanism in Dental Thermoforming
1
作者 Mutsumi Takahashi Masatoshi Takeuchi 《Materials Sciences and Applications》 2024年第9期350-357,共8页
Effectiveness and safety of a sports mouthguard depend on its thickness and material, and the thermoforming process affects these. The purpose of this study was to clarify the effects of differences in molding mechani... Effectiveness and safety of a sports mouthguard depend on its thickness and material, and the thermoforming process affects these. The purpose of this study was to clarify the effects of differences in molding mechanisms on the lower molding temperature limit and molding time in dental thermoforming. Ethylene vinyl acetate resin mouthguard sheet and two thermoforming machines;vacuum blower molding machine and vacuum ejector/pressure molding machine were used. The molding pressures for suction molding were −0.018 MPa for vacuum blower molding and −0.090 MPa for vacuum ejector molding, and for pressure molding was set to 0.090 MPa or 0.450 MPa. Based on the manufacturer’s standard molding temperature of 95˚C, the molding temperature was lowered in 2.5˚C increments to determine the lower molding temperature limit at which no molding defects occurred. In order to investigate the difference in molding time depending on the molding mechanism, the duration of molding pressure was adjusted in each molding machine, and the molding time required to obtain a sample without molding defects was measured. The molding time of each molding machine were compared using one-way analysis of variance. The lower molding temperature limit was 90.0˚C for the vacuum blower machine, 77.5˚C for the vacuum ejector machine, 77.5˚C for the pressure molding machine at 0.090 MPa, and 67.5˚C for the pressure molding machine at 0.45 MPa. The lower molding temperature limit was higher for lower absolute values of molding pressure. The molding time was shorter for pressure molding than for suction molding. Significant differences were observed between all conditions except between the pressure molding machine at 0.090 MPa and 0.45 MPa (P < 0.01). A comparison of the differences in lower molding temperature limit and molding time due to molding mechanisms in dental thermoforming revealed that the lower molding temperature limit depends on the molding pressure and that the molding time is longer for suction molding than for pressure molding. 展开更多
关键词 theRMOforMING Suction Molding Pressure Molding Lower Molding Temperature Limit Molding time
下载PDF
Improving Prediction Efficiency of Machine Learning Models for Cardiovascular Disease in IoST-Based Systems through Hyperparameter Optimization
2
作者 Tajim Md.Niamat Ullah Akhund Waleed M.Al-Nuwaiser 《Computers, Materials & Continua》 SCIE EI 2024年第9期3485-3506,共22页
This study explores the impact of hyperparameter optimization on machine learning models for predicting cardiovascular disease using data from an IoST(Internet of Sensing Things)device.Ten distinct machine learning ap... This study explores the impact of hyperparameter optimization on machine learning models for predicting cardiovascular disease using data from an IoST(Internet of Sensing Things)device.Ten distinct machine learning approaches were implemented and systematically evaluated before and after hyperparameter tuning.Significant improvements were observed across various models,with SVM and Neural Networks consistently showing enhanced performance metrics such as F1-Score,recall,and precision.The study underscores the critical role of tailored hyperparameter tuning in optimizing these models,revealing diverse outcomes among algorithms.Decision Trees and Random Forests exhibited stable performance throughout the evaluation.While enhancing accuracy,hyperparameter optimization also led to increased execution time.Visual representations and comprehensive results support the findings,confirming the hypothesis that optimizing parameters can effectively enhance predictive capabilities in cardiovascular disease.This research contributes to advancing the understanding and application of machine learning in healthcare,particularly in improving predictive accuracy for cardiovascular disease management and intervention strategies. 展开更多
关键词 Internet of sensing things(IoST) machine learning hyperparameter optimization cardiovascular disease prediction execution time analysis performance analysis wilcoxon signed-rank test
下载PDF
OUTPUT REGULATION OF THE GENERAL NONLINEARDISCRETE-TIME SYSTEM
3
作者 李铁成 王照林 李俊峰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第2期200-204,共5页
With the use of centre manifold and dynamic system theory, the necessary and sufficient conditions are obtained for the solvabilities of the output regulator problems for the general nonlinear discrete-time system. Th... With the use of centre manifold and dynamic system theory, the necessary and sufficient conditions are obtained for the solvabilities of the output regulator problems for the general nonlinear discrete-time system. This work generalizes and refines the corresponding results by Isidori and Byrnes on the affine nonlinear continuous-time 'system. 展开更多
关键词 discrete-time system output regulation centre manifold exponential stability omega-limit set
下载PDF
Whether is the Time Limit of Litigation/Arbitration Suspended if one of the Parties Only Submits the Application for Arbitration to the Arbitration Commission?
4
《China's Foreign Trade》 2001年第8期44-44,共1页
关键词 Whether is the time Limit of Litigation/Arbitration Suspended if one of the Parties Only Submits the Application for Arbitration to the Arbitration Commission
下载PDF
Machine Learning Driven Latency Optimization for Internet of Things Applications in Edge Computing 被引量:1
5
作者 Uchechukwu AWADA ZHANG Jiankang +2 位作者 CHEN Sheng LI Shuangzhi YANG Shouyi 《ZTE Communications》 2023年第2期40-52,共13页
Emerging Internet of Things(IoT)applications require faster execution time and response time to achieve optimal performance.However,most IoT devices have limited or no computing capability to achieve such stringent ap... Emerging Internet of Things(IoT)applications require faster execution time and response time to achieve optimal performance.However,most IoT devices have limited or no computing capability to achieve such stringent application requirements.To this end,computation offloading in edge computing has been used for IoT systems to achieve the desired performance.Nevertheless,randomly offloading applications to any available edge without considering their resource demands,inter-application dependencies and edge resource availability may eventually result in execution delay and performance degradation.We introduce Edge-IoT,a machine learning-enabled orchestration framework in this paper,which utilizes the states of edge resources and application resource requirements to facilitate a resource-aware offloading scheme for minimizing the average latency.We further propose a variant bin-packing optimization model that co-locates applications firmly on edge resources to fully utilize available resources.Extensive experiments show the effectiveness and resource efficiency of the proposed approach. 展开更多
关键词 edge computing execution time IOT machine learning resource efficiency
下载PDF
PERFORMANCE ANALYSIS OF POLLING SYSTEMS WITH LIMITED SERVICE 被引量:12
6
作者 Zhao Dongfeng Li Bihai Zheng Sumin(Department of Information and Electronic Science, Yunnan University, Kunming 650091) 《Journal of Electronics(China)》 1998年第1期43-49,共7页
This paper analyzes a queue mode] of the polling system with limited service (K=1) in discrete time. By the imbedded Markov chain theory and the probability generating function method, the mean values of queue length ... This paper analyzes a queue mode] of the polling system with limited service (K=1) in discrete time. By the imbedded Markov chain theory and the probability generating function method, the mean values of queue length and message waiting time are explicitly obtained. Also, we give the simulation results. The results obtained by H. Tagai (1985) are revised. 展开更多
关键词 POLLING system LIMITED SERVICE DISCRETE time
下载PDF
CENTRAL LIMIT THEOREMS FOR A BRANCHING RANDOM WALK WITH A RANDOM ENVIRONMENT IN TIME 被引量:7
7
作者 高志强 刘全升 汪和松 《Acta Mathematica Scientia》 SCIE CSCD 2014年第2期501-512,共12页
We consider a branching random walk with a random environment m time, in which the offspring distribution of a particle of generation n and the distribution of the displacements of its children depend on an environmen... We consider a branching random walk with a random environment m time, in which the offspring distribution of a particle of generation n and the distribution of the displacements of its children depend on an environment indexed by the time n. The envi- ronment is supposed to be independent and identically distributed. For A C R, let Zn(A) be the number of particles of generation n located in A. We show central limit theorems for the counting measure Zn (-) with appropriate normalization. 展开更多
关键词 Branching random walk random environment in time central limit theorems
下载PDF
RELAXATION TIME LIMITS PROBLEM FOR HYDRODYNAMIC MODELS IN SEMICONDUCTOR SCIENCE 被引量:3
8
作者 黎勇 《Acta Mathematica Scientia》 SCIE CSCD 2007年第2期437-448,共12页
In this article, two relaxation time limits, namely, the momentum relaxation time limit and the energy relaxation time limit are considered. By the compactness argument, it is obtained that the smooth solutions of the... In this article, two relaxation time limits, namely, the momentum relaxation time limit and the energy relaxation time limit are considered. By the compactness argument, it is obtained that the smooth solutions of the multidimensional nonisentropic Euler-Poisson problem converge to the solutions of an energy transport model or a drift diffusion model, respectively, with respect to different time scales. 展开更多
关键词 Hydrodynamic models nonisentropic Euler-Poisson momentum relaxation time limit energy relaxation time limit
下载PDF
Event-Triggered Sliding Mode Control for Trajectory Tracking of Nonlinear Systems 被引量:6
9
作者 Aquib Mustafa Narendra K.Dhar Nishchal K Verma 《IEEE/CAA Journal of Automatica Sinica》 EI CSCD 2020年第1期307-314,共8页
In this paper, an event-triggered sliding mode control approach for trajectory tracking problem of nonlinear input affine system with disturbance has been proposed. A second order robotic manipulator system has been m... In this paper, an event-triggered sliding mode control approach for trajectory tracking problem of nonlinear input affine system with disturbance has been proposed. A second order robotic manipulator system has been modeled into a general nonlinear input affine system. Initially, the global asymptotic stability is ensured with conventional periodic sampling approach for reference trajectory tracking. Then the proposed approach of event-triggered sliding mode control is discussed which guarantees semi-global uniform ultimate boundedness. The proposed control approach guarantees non-accumulation of control updates ensuring lower bounds on inter-event triggering instants avoiding Zeno behavior in presence of the disturbance. The system shows better performance in terms of reduced control updates, ensures system stability which further guarantees optimization of resource usage and cost. The simulation results are provided for validation of proposed methodology for tracking problem by a robotic manipulator. The number of aperiodic control updates is found to be approximately 44% and 61% in the presence of constant and time-varying disturbances respectively. 展开更多
关键词 Event-trigger inter execution time STABILITY sliding mode control trajectory tracking
下载PDF
Reliable Estimation of Execution Time of MapReduce Program 被引量:1
10
作者 杨肖 孙建伶 《China Communications》 SCIE CSCD 2011年第6期11-18,共8页
As data volume grows, many enterprises are considering using MapReduce for its simplicity. However, how to evaluate the performance improvement before deployment is still an issue. Current researches of MapReduce perf... As data volume grows, many enterprises are considering using MapReduce for its simplicity. However, how to evaluate the performance improvement before deployment is still an issue. Current researches of MapReduce performance are mainly based on monitoring and simulation, and lack mathematical models. In this paper, we present a simple but powerful performance model for the prediction of the execution time of a MapReduce program with limited resources. We study each component of MapReduce framework, and analyze the relation between the overall performance and the number of mappers and reducers based on our model. Two typical MapReduce programs are evaluated in a small cluster with 13 nodes. Experimental results show that the mathematical performance model can estimate the execution time of MapReduce programs reliably. According to our model, number of mappers and reducers can be tuned to form a better execution pipeline and lead to better performance. The model also points out potential bottlenecks of the framework and future improvement. 展开更多
关键词 performance model MAPREDUCE execution time
下载PDF
Statistical Properties and Confidence Limits about the Mean Time between the Failures (MTBF) in Failure-free Period Life Test (FFPLT)
11
作者 王庆成 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第1期9-19,共11页
On the basis of strict mathematical description about Failure_Free Period Life Test (FFPLT), the statistical properties of the tests and optimal confidence limit of the parameter are discussed in detail and correspond... On the basis of strict mathematical description about Failure_Free Period Life Test (FFPLT), the statistical properties of the tests and optimal confidence limit of the parameter are discussed in detail and corresponding calculating formulae are found out. 展开更多
关键词 FFPLT MTBF operating characteristic (OC) function expected test time (ETT) maximum likelihood estimation lower confidence limit
下载PDF
Quantum speed limit time of a non-Hermitian two-level system
12
作者 Yan-Yi Wang Mao-Fa Fang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期89-94,共6页
We investigated the quantum speed limit time of a non-Hermitian two-level system for which gain and loss of energy or amplitude are present. Our results show that, with respect to two distinguishable states of the non... We investigated the quantum speed limit time of a non-Hermitian two-level system for which gain and loss of energy or amplitude are present. Our results show that, with respect to two distinguishable states of the non-Hermitian system, the evolutionary time does not have a nonzero lower bound. The quantum evolution of the system can be effectively accelerated by adjusting the non-Hermitian parameter, as well as the quantum speed limit time can be arbitrarily small even be zero. 展开更多
关键词 QUANTUM SPEED LIMIT time NON-HERMITIAN dynamics QUANTUM OPTICS
下载PDF
Research on Multi-Core Processor Analysis for WCET Estimation
13
作者 LUO Haoran HU Shuisong +2 位作者 WANG Wenyong TANG Yuke ZHOU Junwei 《ZTE Communications》 2024年第1期87-94,共8页
Real-time system timing analysis is crucial for estimating the worst-case execution time(WCET)of a program.To achieve this,static or dynamic analysis methods are used,along with targeted modeling of the actual hardwar... Real-time system timing analysis is crucial for estimating the worst-case execution time(WCET)of a program.To achieve this,static or dynamic analysis methods are used,along with targeted modeling of the actual hardware system.This literature review focuses on calculating WCET for multi-core processors,providing a survey of traditional methods used for static and dynamic analysis and highlighting the major challenges that arise from different program execution scenarios on multi-core platforms.This paper outlines the strengths and weaknesses of current methodologies and offers insights into prospective areas of research on multi-core analysis.By presenting a comprehensive analysis of the current state of research on multi-core processor analysis for WCET estimation,this review aims to serve as a valuable resource for researchers and practitioners in the field. 展开更多
关键词 real-time system worst-case execution time(WCET) multi-core analysis
下载PDF
The Dynamic Relationship of Brain Networks Across Time Windows During Product-Based Creative Thinking
14
作者 Yu-chu Yeh Wei-Chin Hsu Elisa Marie Rega 《Psychology Research》 2019年第10期401-419,共19页
Consensus of creativity research suggests that the measurement of both originality and valuableness is necessary when designing creativity tasks.However,few studies have emphasized valuableness when exploring underlyi... Consensus of creativity research suggests that the measurement of both originality and valuableness is necessary when designing creativity tasks.However,few studies have emphasized valuableness when exploring underlying neural substrates of creative thinking.The present study employs product-based creativity tasks that measure both originality and valuableness in an exploration of the dynamic relationship between the default mode(DMN),executive control(ECN),and salience(SN)networks through time windows.This methodology highlights relevance,or valuableness,in creativity evaluation as opposed to divergent thinking tasks solely measuring originality.The researchers identified seven brain regions belonging to the ECN,DMN,and SN as regions of interest(ROIs),as well as four representative seeds to analyze functional connectivity in 25 college student participants.Results showed that all of the identified ROIs were involved during the creative task.The insula,precuneus,and ventrolateral prefrontal cortex(vlPFC)remained active across all stages of product-based creative thinking.Moreover,the connectivity analyses revealed varied interaction patterns of DMN,ECN,and SN at different thinking stages.The integrated findings of the whole brain,ROI,and connectivity analyses suggest a trend that the DMN and SN(which relate to bottom-up thinking)attenuate as time proceeds,whereas the vlPFC(which relates to top-down thinking)gets stronger at later stages;these findings reflect the nature of our creativity tasks and decision-making of valuableness in later stages.Based on brain region activation throughout execution of the task,we propose that product-based creative process may include three stages:exploration and association,incubation and insight,and finally,evaluation and decision making.This model provides a thinking frame for further research and classroom instruction. 展开更多
关键词 default mode network dynamic connectivity executive control network product-based creativity salience network time window
下载PDF
The Space Dilation: Analyzing Progressive Speed Reduction and Its Relativistic Parallels
15
作者 Kreshnik Feka 《Journal of Applied Mathematics and Physics》 2024年第8期2990-3005,共16页
This paper presents a conceptual exploration that draws an intriguing parallelbetween a hypothetical travel scenario and the principles of special relativity. The scenario involves a traveler who reduces their speed b... This paper presents a conceptual exploration that draws an intriguing parallelbetween a hypothetical travel scenario and the principles of special relativity. The scenario involves a traveler who reduces their speed by an amount proportional to the distance traveled. Despite initially traveling at a high speed towards a given destination, the continual reduction in speed results in an asymptotic approach to the goal, analogous to the unattainable speed of light in relativity. Mathematically, the scenario is expressed through the Harmonic Series, demonstrating that the total travel time increases without bound, making the destination theoretically unreachable within a finite timeframe. This exploration mirrors the relativistic velocity addition and time dilation effects, providing a compelling analogy for understanding asymptotic limits. By highlighting the profound implications of diminishing returns and unattainable goals, this paper aims to stimulate further discussion and exploration of these fascinating parallels. 展开更多
关键词 Asymptotic limits Special Relativity Harmonic Series time Dilation Diminishing Returns
下载PDF
Determination of the Financing Scale,Time Limit and Returns from the Investment in BOT Projects
16
作者 Chen Shouke Wei Zhuobin 《Engineering Sciences》 EI 2008年第1期83-89,共7页
The key aspect to the successful implementation of BOT concept is the raising of finance by project sponsor,so financial engineering techniques and capital structuring skills are required to find the proper mix of deb... The key aspect to the successful implementation of BOT concept is the raising of finance by project sponsor,so financial engineering techniques and capital structuring skills are required to find the proper mix of debt and equity.The capital structure and present a model to determine the equity level from the aspects of financing scale,construction time and return on investment are analyzed.The resulting model can help the sponsor to avoid the capital risk,and offer the government a criterion to evaluate management ability of the sponsor.To show the application and availability of this model,a case study is conducted.Thus,this paper is concern with the determination of financing scale,construction time,and return on investment which would assist the sponsor to ensure that the equity level for optimal capital structure is available prior to the implementation stage in BOT project operation. 展开更多
关键词 capital risk financing scale time limit returns of investment BOT project
下载PDF
Employing Two ‘Sandwich Delay’ Mechanisms to Enhance Predictability of Embedded Systems Which Use Time-Triggered Co-Operative Architectures 被引量:1
17
作者 Mouaaz Nahas 《Journal of Software Engineering and Applications》 2011年第7期417-425,共9页
In many real-time resource-constrained embedded systems, highly-predictable system behavior is a key design requirement. The “time-triggered co-operative” (TTC) scheduling algorithm provides a good match for a wide ... In many real-time resource-constrained embedded systems, highly-predictable system behavior is a key design requirement. The “time-triggered co-operative” (TTC) scheduling algorithm provides a good match for a wide range of low-cost embedded applications. As a consequence of the resource, timing, and power constraints, the implementation of such algorithm is often far from trivial. Thus, basic implementation of TTC algorithm can result in excessive levels of task jitter which may jeopardize the predictability of many time-critical applications using this algorithm. This paper discusses the main sources of jitter in earlier TTC implementations and develops two alternative implementations – based on the employment of “sandwich delay” (SD) mechanisms – to reduce task jitter in TTC system significantly. In addition to jitter levels at task release times, we also assess the CPU, memory and power requirements involved in practical implementations of the proposed schedulers. The paper concludes that the TTC scheduler implementation using “multiple timer interrupt” (MTI) technique achieves better performance in terms of timing behavior and resource utilization as opposed to the other implementation which is based on a simple SD mechanism. Use of MTI technique is also found to provide a simple solution to “task overrun” problem which may degrade the performance of many TTC systems. 展开更多
关键词 time-TRIGGERED Co-Operative Cyclic Executive Jitter SANDWICH DELAY Multiple timeR INTERRUPTS Task OVERRUN
下载PDF
Cross the chasm from the immediate execution of death penalty to the death sentence with a reprieve --- Interpretation of the "not to execute immediately"
18
作者 Xiao Yuqin 《International English Education Research》 2015年第1期57-60,共4页
Retaining the death penalty and strict restricting the application of the death penalty is now a basic criminal policy in China, and from the judicial level, the key to the restriction of the death penalty is to study... Retaining the death penalty and strict restricting the application of the death penalty is now a basic criminal policy in China, and from the judicial level, the key to the restriction of the death penalty is to study what lenient sentencing discretion the criminal has to constitute "not to execute immediately" when he has reached the standard of the immediate execution of the death penalty, to cross the chasm from the immediate execution of the death penalty to the death sentence with a reprieve. The basic process of the sentencing is to establish a baseline punishment on the basis of the social harmfulness of the activities of the criminal, and then measure the profits and losses according to the offender's personal danger. Therefore, although the social harmfulness of the activities of the criminal reaches the standard of the "most heinous crimes", due to the existence of the fault of the victim, active compensation for the victim, and the motives of the small blames and other lenient sentencing discretions, the criminal's danger has not reached the degree of "flagrance". Apply the death sentence with a two-year reprieve and even the life imprisonment generally. If there are some strict sentencing discretions, such as "the crime means is extremely cruel", carefully consider the use of the immediate execution of the death penalty. Under the circumstances of the concurrence of the sentencing, carry on the overall consideration based on the comprehensive measurement of various circumstances of the sentencing. 展开更多
关键词 Limit the immediate execution of the death penalty the discretionary circumstances of sentencing individualization of the criminalpenalty
下载PDF
Extention of Time Limit Mandated by SIPO(as basically limited to one extention and for two months at most)
19
《中国专利与商标》 1999年第4期17-17,共1页
The State Intellectual Poperty Office has announcedan amendment to Sec.5,Paragrph 4.2.of Chapter 7 ofExamination Guidelines.According to the newregulations,for making a respon to an office actionduring the prosecution... The State Intellectual Poperty Office has announcedan amendment to Sec.5,Paragrph 4.2.of Chapter 7 ofExamination Guidelines.According to the newregulations,for making a respon to an office actionduring the prosecution of a patent application,only a firstrequest for a two-month extension of time can be basicallyallowed upon payment of official fee of RMB300(aboutUSD36).For further extension after the first one,onlyanother request for one or two months,at most twomonths,would be possibly petitioned together with a copyof the client’s instructions of the further extension and 展开更多
关键词 as basically limited to one extention and for two months at most Extention of time Limit Mandated by SIPO
下载PDF
A Requirements Engineering Environment for Embedded Real-Time Software—SREE
20
作者 LI Yonghua SHU Fengdi +1 位作者 WU Guoqing LIANG Zhengping 《Wuhan University Journal of Natural Sciences》 CAS 2006年第3期533-538,共6页
The paper presents the embedded real-time software-oriented requirements engineering environment—SREZ. It involves the whole process of software requirements engineering, including the definition, analysis and checki... The paper presents the embedded real-time software-oriented requirements engineering environment—SREZ. It involves the whole process of software requirements engineering, including the definition, analysis and checking of requirements ,specifications. We first explain the principles of the executable specification language RTRSM. Subsequently, we introduce the main functions of SREE, illustrate the methods and techniques of checking requirements specifications, especially how to perform simulation execution, combining prototyping method with RTRSM and animated representations. At last, we compare the SREE with other requirements specifications methods and make a summary for SREE's advantages. 展开更多
关键词 embedded real-time system requirements specification requirements verification simulation execution
下载PDF
上一页 1 2 135 下一页 到第
使用帮助 返回顶部