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Emergence of Time From Quantum Physics as Opposed to Abstraction of Time Components in Biopsychology 预览
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作者 Franz Klaus Jansen 《哲学研究:英文版》 2019年第2期74-85,共12页
Time is a highly complex concept,which is daily experienced as qualitative reality,utilized in science and classical physics as quantitative units,but denied by quantum physics.The time concept can be explained as eme... Time is a highly complex concept,which is daily experienced as qualitative reality,utilized in science and classical physics as quantitative units,but denied by quantum physics.The time concept can be explained as emergence from the physics perspective,or as abstraction of time components,in the context of biopsychology,where quantitative time components are associated with the initial qualitative concept of time experience.Successive abstraction of the associated components renders the time concept more adaptable to different situations in both physics and daily life.The aspect of tense—with past,present,and future—positions time with respect to specific observers.However,as in physics,many experimental outcomes have to be grouped and individual;tenses must be excluded.The same is true for individual calendar references,which have to be replaced by time units.Newton’s absolute time was replaced in Einstein’s relativity theory by relative time.Whereas the aforementioned time concepts were based on waiting time corresponding to time flow characterized by waiting intervals between successive events,physics requires reference time stored on any kind of support,such as human memory or a magnetic deviceonly identifying time as its sources,.With support-fixed time,successive events are simultaneously accessible on the support,thus eliminating the waiting intervals.Support fixed time can be reduced to simple relations that appear timeless,and are more adapted to physical formalism. 展开更多
关键词 composite TIME TENSE TIME flow TIME relations quantum PHYSICS
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General way to define tunneling time
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作者 舒正 郝小雷 +1 位作者 李卫东 陈京 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第5期27-31,共5页
With the development of attosecond science, tunneling time can now be measured experimentally with the attoclock technique. However, there are many different theoretical definitions of tunneling time and no consensus ... With the development of attosecond science, tunneling time can now be measured experimentally with the attoclock technique. However, there are many different theoretical definitions of tunneling time and no consensus has been achieved.Here, we bridge the relationship between different definitions of tunneling time based on a quantum travel time in onedimensional rectangular barrier tunneling problem. We find that the real quantum travel time tRe is equal to the Bohmian time tBohmian, which is related to the resonance lifetime of a bound state. The total quantum travel time τt can perfectly retrieve the transversal time tx and the Büttiker–Landauer time τBL in two opposite limits, regardless of the particle energy. 展开更多
关键词 TUNNELING TIME Buttiker–Landauer TIME Bohmian TIME
The time model for event processing in internet of things
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作者 Chunjie ZHOU Xiaoling WANG +2 位作者 Zhiwang ZHANG Zhenxing ZHANG Haiping QU 《中国计算机科学前沿:英文版》 SCIE EI CSCD 2019年第3期471-488,共18页
The time management model for event processing in internet of things has a special and important requirement. Many events in real world applications are long-lasting events which have different time granularity with o... The time management model for event processing in internet of things has a special and important requirement. Many events in real world applications are long-lasting events which have different time granularity with order or out-of-order. The temporal relationships among those events are often complex. An important issue of complex event processing is to extract patterns from event streams to support decision making in real-time. However, current time management model does not consider the unified solution about time granularity, time interval, time disorder, and the difference between workday calendar systems in different organizations. In this work, we analyze the preliminaries of temporal semantics of events. A tree-plan model of out-of-order durable events is proposed. A hybrid solution is correspondingly introduced. A case study is illustrated to explain the time constraints and the time optimization. Extensive experi? mental studies demonstrate the efficiency of our approach. 展开更多
关键词 TIME model EVENT processing internet of THINGS TIME INTERVAL TIME DISORDER
Analyzing distributions for travel time data collected using radiofrequency identification technique in urban road networks
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作者 GUO JianHua LI ChangGuang +3 位作者 QIN Xiao HUANG Wei WEI Yun CAO JinDe 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第1期106-120,共15页
Travel time distribution studies are fundamental for supporting transportation system reliability studies, particularly for urban road networks. However, such studies are generally based on travel time data sets with ... Travel time distribution studies are fundamental for supporting transportation system reliability studies, particularly for urban road networks. However, such studies are generally based on travel time data sets with limited sample sizes, which provide inconsistent findings. In this paper, a large amount of travel time data collected from the emerging radio frequency identification(RFID) technique are used to conduct empirical investigations and estimations of travel time distributions, and three major findings are determined. First, travel time data are shown to have a complex statistical structure: the travel time distribution is in general peaky, multi-modal, and skewed to the right, which cross validates findings shown in previous publications. Second, unimodal distribution models are shown to be unable to capture the complex statistical dynamics embedded in the travel time data;therefore,a multistate distribution model is more appropriate for modeling travel time distributions. In this respect, a three-component gaussian mixture model(GMM) is tested and results consistently outperform those of unimodal distribution models. Finally, the aggregation time interval is shown to have a trivial effect on the shape of travel time distributions: the travel time distribution is stable under different aggregation time intervals. Future work is recommended to investigate further travel time variabilities and travel time distribution estimations. 展开更多
关键词 reliability TRAVEL TIME TRAVEL TIME distribution TIME INTERVAL RFID
LSTM Based Reserve Prediction for Bank Outlets
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作者 Yu Liu Shuting Dong +1 位作者 Mingming Lu Jianxin Wang 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第1期77-85,共9页
Reserve allocation is a significant problem faced by commercial banking businesses every day.To satisfy the cash requirement of customers and abate the vault cash pressure,commercial banks need to appropriately alloca... Reserve allocation is a significant problem faced by commercial banking businesses every day.To satisfy the cash requirement of customers and abate the vault cash pressure,commercial banks need to appropriately allocate reserves for each bank outlet.Excessive reserve would impact the revenue of bank outlets.Low reserves cannot guarantee the successful operation of bank outlets.Considering the reserve requirement is effected by the past cash balance,we deal the reserve allocation problem as a time series prediction problem,and the Long Short Time Memory (LSTM)network is adapted to solve it.In addition,the proposed LSTM prediction model regards date property,which can affect the cash balance,as a primary factor.The experiment results show that our method outperforms some existing traditional methods. 展开更多
关键词 RESERVE PREDICTION TIME series PREDICTION LONG SHORT TIME Memory (LSTM)network DATE property
Planned Disregard in Consumer Relations: A Proposition to Redress Consumer’s Lost Time 预览
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作者 Laís Bergstein 《美中法律评论:英文版》 2019年第4期133-142,共10页
Time exerts multiple influences on consumer relations since it is a triggering factor for several legal obligations, especially in long-term contractual bounds. The valuation of time as an essential and limited resour... Time exerts multiple influences on consumer relations since it is a triggering factor for several legal obligations, especially in long-term contractual bounds. The valuation of time as an essential and limited resource has emerged in the context of post-modernity with the formation of a new consciousness about the effects that its passage exerts on people. In Brazil, especially since 2009, several judicial decisions recognized the time lost by consumers trying to solve conflicts with suppliers as a special kind of moral damage and guaranteed the right to redress. However, many other consumers in similar situations had the same right denied in courts, mostly due to the lack of criteria to compensate the time lost due to acts attributable to suppliers. In this context, the research proposes a double criteria to pursue the adequate compensation for the time lost by consumer through the evaluation of supplier’s conducts. The study makes a distinction of consumer’s time and supplier’s time and defines the commercial practice entitled “planned disregard” as the abusive devaluation of time and the efforts made by consumers to achieve a successful conclusion to consumer contracts, mostly due to the lack of investments in efficient customer care services. This type of commercial practice violates the limits of good faith and represents an excessive advantage for the supplier, breaking the legal balance that the law establishes in consumer relations. The paper also approaches the legal duties of effective prevention and full redress of damages in Brazilian consumer law which are the legal tools to compensate the damage due to the loss of time suffered by consumers. Finally, it suggests how the members of the national consumer protection system, such as the regulatory agencies, civil entities, and the judiciary may contribute with structural processes to the prevention of undue loss of consumer time. 展开更多
关键词 consumer TIME PLANNED disregard damage DUE to TIME LOST full redress structural processes
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Magnetic resonance imaging of the zone of calcified cartilage in the knee joint using 3-dimensional ultrashort echo time cones sequences
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作者 Jin Liu Yang Wei +3 位作者 Ya-Jun Ma Yan-Chun Zhu Quan Zhou Ying-Hua Zhao 《中华医学杂志:英文版》 SCIE CAS CSCD 2019年第5期562-568,共7页
Background: The zone of calcified cartilage (ZCC) plays an important role in the pathogenesis of osteoarthritis (OA) but has never been imaged in vivo with magnetic resonance (MR) imaging techniques. We investigated t... Background: The zone of calcified cartilage (ZCC) plays an important role in the pathogenesis of osteoarthritis (OA) but has never been imaged in vivo with magnetic resonance (MR) imaging techniques. We investigated the feasibility of direct imaging of the ZCC in both cadaveric whole knee specimens and in vivo healthy knees using a 3-dimensional ultrashort echo time cones (3D UTE-Cones) sequence on a clinical 3T scanner. Methods: In all, 12 cadaveric knee joints and 10 in vivo healthy were collected. At a 3T MR scanner with an 8-channel knee coil, a fat-saturated 3D dual-echo UTE-Cones sequence was used to image the ZCC, following with a short rectangular pulse excitation and 3D spiral sampling with conical view ordering. The regions of interests (ROIs) were delineated by a blinded observer. Singlecomponent T2* and T2 values were calculated from fat-saturated 3D dual-echo UTE-Cones and a Carr-Purcell-Meiboom-Gill (T2 CPMG) data using a semi-automated MATLAB code. Results: The single-exponential fitting curve of ZCC was accurately obtained with R2 of 0.989. For keen joint samples, the ZCC has a short T2* ranging from 0.62 to 2.55 ms, with the mean ±standard deviation (SD) of 1.49 ±0.66 ms, and with 95% confidence intervals (CI) of 1.20-1.78 ms. For volunteers, the short T2* ranges from 0.93 to 3.52ms, with the mean±SD of 2.09±0.56 ms, and the 95% CI is 1.43 to 2.74ms in ZCC. Conclusions: The high-resolution 3D UTE-Cones sequence might be used to directly image ZCC in the human knee joint on a clinical 3T scanner with a scan time of more than 10 min. Using this non-invasive technique, the T2* relaxation time of the ZCC can be further detected. 展开更多
关键词 ULTRASHORT echo TIME T2* relaxation TIME ZONE of CALCIFIED CARTILAGE ARTICULAR CARTILAGE
Dual-cavity beam arrival time monitor design for the Shanghai soft X-ray FEL facility 预览
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作者 Shan-Shan Cao Ren-Xian Yuan +1 位作者 Jian Chen Yong-Bin Leng 《核技术:英文版》 SCIE CAS CSCD 2019年第5期14-21,共8页
Free electron lasers provide high-power and ultrashort pulses with extreme brightness. In order to improve a facility’s capabilities and explore the possibility of performing high-resolution time-resolved experiments... Free electron lasers provide high-power and ultrashort pulses with extreme brightness. In order to improve a facility’s capabilities and explore the possibility of performing high-resolution time-resolved experiments, a beam arrival time resolution under 100 fs is required. In this article, a novel beam arrival time monitor (BAM) equipped with two cavities has been designed and a beam flight time measurement scheme based on the BAM prototype has been proposed to estimate phase jitter in the signal measurement system. The two BAM cavities work at different frequencies and the frequency difference is designed to be 35 MHz. Therefore, a self-mixing intermediate frequency signal can be generated using the two cavities. The measured beam flight time shows a temporal deviation of 37 fs (rms). 展开更多
关键词 BEAM ARRIVAL TIME MONITOR Dual-cavities BEAM flight TIME SELF-MIXING
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Slavery Act:Modification of the Hungarian Labour Code--Legal Analysis 预览
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作者 Gábor Kertész 《管理研究:英文版》 2019年第4期338-345,共8页
In the middle of December 2018,Hungary has suddenly appeared in the headlines of international news.Although marketing teaches that“all PR is good PR”,as a lawyer,the author thinks it is worth examining the facts be... In the middle of December 2018,Hungary has suddenly appeared in the headlines of international news.Although marketing teaches that“all PR is good PR”,as a lawyer,the author thinks it is worth examining the facts behind the catchy headlines well before making our business decisions.The news is based on the amendment of the Labour Code,which is called the“Slavery Act”in the media.The demonstrations and atrocities reported by the international media have broken out as a result of the interpretation of the amendment by some part of the media,which was recently adopted by Parliament.The President of Hungary promulgated the act when this article was completed.What does the new amendment say?Could an employee become a“slave”of the employer,or rather it would help people’s prosperity by allow them to work more to earn more money?Considering the interests of the citizens/employees,can the choice between adoption or rejection of the law be the only possibility,does the new system also have a third possibility using the law’s and the economy’s own logic,or should only a small“fine-tuning”be implemented on the new system? 展开更多
关键词 labour law working TIME FRAME OVERWORK MAXIMUM working TIME
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Experimental investigation of the detection and location of a target in layered media by using the TR-RTM mixed method
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作者 Xiang Gao Jian Li +4 位作者 Jun Ma JunHong Li FangFang Shi Wen Wang ChengHao Wang 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第3期75-81,共7页
Targets in layered media can be detected and located using a time reversal(TR)-reversed-time migration(RTM)mixed method.In this study,this single emission-multiple receiving method is tested experimentally by using tw... Targets in layered media can be detected and located using a time reversal(TR)-reversed-time migration(RTM)mixed method.In this study,this single emission-multiple receiving method is tested experimentally by using two types of layered media and three types of targets.The signal reflected at the interface and the signal scattered by the target are measured by each receiver to obtain the travel time for several transmitter-receiver pairs.Thereafter,the amplitude ratio between the two measured signals is compared with the theoretical amplitude.The RTM process involves the convolution of the forward acoustic beam from the source with the backward acoustic beam from the receiver which adds an appropriate delay determined on the measured travel time data.By using this approach,the acoustic field distribution can be obtained,and the position of the target can be determined.Moreover,the measured positions of the target are compared with the actual position to validate the accuracy of this technique. 展开更多
关键词 time REVERSAL reversed-time migration ultrasonic detection LAYERED media
A new dynamic pushback control method for reducing fuel-burn costs: Using predicted taxi-out time
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作者 Guan LIAN Yaping ZHANG +2 位作者 Zhiwei XING Qian LUO Shaowu CHENG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第3期660-673,共14页
Long departure-taxi-out time leads to significant airport surface congestion, fuel-burn costs, and excessive emissions of greenhouse gases. To reduce these undesirable effects, a Predicted taxi-out time-based Dynamic ... Long departure-taxi-out time leads to significant airport surface congestion, fuel-burn costs, and excessive emissions of greenhouse gases. To reduce these undesirable effects, a Predicted taxi-out time-based Dynamic Pushback Control(PDPC) method is proposed. The implementation of this method requires two steps: first, the taxi-out times for aircraft are predicted by the leastsquares support-vector regression approach of which the parameters are optimized by an introduced improved Firefly algorithm. Then, a dynamic pushback control model equipped with a linear gate-hold penalty function is built, along with a proposed iterative taxiway queue-threshold optimization algorithm for solving the model. A case study with data obtained from Beijing International airport(PEK) is presented. The taxi-out time prediction model achieves predictive accuracy within 3 min and 5 min by 84.71% and 95.66%, respectively. The results of the proposed pushback method show that total operation cost and fuel-burn cost achieve a 14.0% and 21.1%reduction, respectively, as compared to the traditional K-control policy.(3) From the perspective of implementation, using PDPC policy can significantly reduce the queue length in taxiway and taxi-out time. The total operation cost and fuel-burn cost can be curtailed by 37.2% and 52.1%,respectively, as compared to the non-enforcement of any pushback control mechanism. These results show that the proposed pushback control model can reduce fuel-burn costs and airport surface congestion effectively. 展开更多
关键词 Airport surface operation Fuel-burn cost Gate-hold TIME Pushback control Taxi-out TIME prediction Taxiway queue threshold
Extraction Process of Basil Essential Oil by Steam Distillation 预览
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作者 Xing ZHANG Qun CHEN +1 位作者 Shanshan LI Qingping XUE 《药用植物研究(英文版)》 2019年第2期14-16,共3页
[Objectives] To optimize volatile oil extraction from Ocimum basilicum with the water vapor distillation.[Methods] An orthogonal design was carried out to determine the volume of volatile oil by 3 factors: the immersi... [Objectives] To optimize volatile oil extraction from Ocimum basilicum with the water vapor distillation.[Methods] An orthogonal design was carried out to determine the volume of volatile oil by 3 factors: the immersion time, distillation time, amount of water. The ratio of the oil in inclusion complex was used to evaluate the technology based on the orthogonal design.[Results] The best volatile oil extraction condition was to add 400 mL of water into the mixture of crude drugs, and to extract the herbal medicine for 2 h with advanced soaking for 6 h with water.[Conclusions] The process is stable, reasonable, and feasible. 展开更多
关键词 OCIMUM basilicum L. Volatile oil WATER vapor DISTILLATION SOAKING TIME DISTILLATION TIME Amount of WATER
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DFTracker: detecting double-fetch bugs by multi-taint parallel tracking
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作者 Pengfei WANG Kai LU +1 位作者 Gen LI Xu ZHOU 《中国计算机科学前沿:英文版》 SCIE EI CSCD 2019年第2期247-263,共17页
A race condition is a common trigger for concurrency bugs. As a special case, a race condition can also occur across the kernel and user space causing a doublefetch bug, which is a field that has received little resea... A race condition is a common trigger for concurrency bugs. As a special case, a race condition can also occur across the kernel and user space causing a doublefetch bug, which is a field that has received little research attention. In our work, we first analyzed real-world doublefetch bug cases and extracted two specific patterns for doublefetch bugs. Based on these patter ns, we proposed an approach of multi-taint parallel tracking to detect double-fetch bugs. We also implemented a prototype called DFTracker (doublefetch bug tracker), and we evaluated it with our test suite. Our experiments demonstrated that it could effectively find all the double-fetch bugs in the test suite including eight realworld cases with no false negatives and minor false positives. In addition, we tested it on Linux kernel and found a new double-fetch bug. The execution overhead is approximately 2x for single-file cases and approximately 9x for the whole kernel test, which is acceptable. To the best of the authors1 knowledge, this work is the first to introduce multi-taint parallel tracking to double-fetch bug detection—an innovative method that is specific to double-fetch bug features—and has better path coverage as well as lower runtime overhead than the widely used dynamic approaches. 展开更多
关键词 multi-taint PARALLEL TRACKING DOUBLE FETCH race condition between kernel and user time of check to time of use real-world case analysis Clang Static Analyzer
Quantum-classical correspondence in integrable systems
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作者 Yiqiang Zhao Biao Wu 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2019年第9期95-103,共9页
We find that the quantum-classical correspondence in integrable systems is characterized by two time scales. One is the Ehrenfest time below which the system is classical;the other is the quantum revival time beyond w... We find that the quantum-classical correspondence in integrable systems is characterized by two time scales. One is the Ehrenfest time below which the system is classical;the other is the quantum revival time beyond which the system is fully quantum. In between, the quantum system can be well approximated by classical ensemble distribution in phase space. These results can be summarized in a diagram which we call Ehrenfest diagram. We derive an analytical expression for Ehrenfest time, which is proportional to h-1/2. According to our formula, the Ehrenfest time for the solar-earth system is about 1026 times of the age of the solar system. We also find an analytical expression for the quantum revival time, which is proportional to h-1. Both time scales involve ω(I), the classical frequency as a function of classical action. Our results are numerically illustrated with two simple integrable models. In addition, we show that similar results exist for Bose gases, where 1/N serves as an effective Planck constant. 展开更多
关键词 quantum-classical CORRESPONDENCE Ehrenfest TIME QUANTUM REVIVAL TIME INTEGRABLE systems
Risks of non-conservative design according to ASME B31.1 for high-temperature piping subjected to long-term operation in the creep range 预览
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作者 Hyeong-Yeon Lee Seok-Kwon Son +1 位作者 Min-Gu Won Ji-Young Jeong 《核技术:英文版》 SCIE CAS CSCD 2019年第5期59-69,共11页
This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity anal... This study investigates the risks of non-conservative piping design according to ASME B31.1 for hightemperature piping subjected to long-term operation at high temperature in a creep regime based on a sensitivity analysis of the hold time. Design evaluations of hightemperature piping were conducted over a range of hold times in the creep regime according to ASME B31.1, which implicitly considers the creep effects, and the French high-temperature design code of the RCC-MRx, which explicitly considers the creep effects. Conservatisms were quantified among the codes in terms of the hold times. In the case of B31.1, the design evaluation results do not change depending on the hold time at high temperature, whereas in the case of RCC-MRx, they do. It was shown that the design limits of RCC-MRx were exceeded when the hold time exceeded certain values, whereas those of B31.1 were satisfied regardless of the hold times. Thus, the design evaluations according to B31.1 did not consistently yield conservative results and might lead to nonconservative nonconservative results in the case of long-term operations in the creep range. 展开更多
关键词 ASME B31.1 CREEP HOLD time Hightemperature PIPING RCC-MRx Sensitivity analysis
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大理古城既下山酒店的“空间规划”和“规划空间” 预览
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作者 王飞 《时代建筑》 2019年第4期70-77,共8页
文章解读了大理古城既下山酒店的"空间规划"和"规划空间"。这个由赖国平创立的酒店品牌的第一家酒店由大理本地建筑师赵扬设计。他们在大理古城狭小的基地中创造了这座包含十四间客房、每间客房提供完全不同的文化... 文章解读了大理古城既下山酒店的"空间规划"和"规划空间"。这个由赖国平创立的酒店品牌的第一家酒店由大理本地建筑师赵扬设计。他们在大理古城狭小的基地中创造了这座包含十四间客房、每间客房提供完全不同的文化体验的商旅酒店,建筑的内与外、城市与街道、单体与整体、建筑与庭院、建筑与家具的界线模糊,深深体现了阿道夫·路斯的"空间规划"和《园冶》的造园精髓。 展开更多
关键词 大理 空间规划 规划空间 空间 时间 酒店 混凝土 风化 阿道夫·路斯 《园冶》
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A Role Node The first e-commerce law in the world will impact China's booming market
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作者 Zhang Shasha 《北京周报:英文版》 2019年第4期34-35,共2页
Li Zhi,a postgraduate student at the Chinese Academy of Sciences,always orders his lunch online.On January 4,when he and his two roommates happened to order their takeout lunch from the same restaurant around the same... Li Zhi,a postgraduate student at the Chinese Academy of Sciences,always orders his lunch online.On January 4,when he and his two roommates happened to order their takeout lunch from the same restaurant around the same time,to their surprise,the delivery fee varied.While one paid 3 yuan ($0.44),the other two paid different sums. The fluctuation was by no means an accident. 展开更多
关键词 POSTGRADUATE STUDENT roommates happened AROUND the SAME time
时间在乳腺癌治疗中与方药的关系
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作者 窦建卫 杨硕 +3 位作者 朱中博 杨小娟 叶凯 钱建升 《辽宁中医杂志》 CAS 2019年第3期499-500,共2页
目前乳腺癌的治疗方法主要以西医为主,中医为辅,两者相结合,往往能发挥出更好的疗效。但以往两者在运用上,又相对独立,唯独时间疗法可以贯穿所有治疗当中。一年有12个月,一天有12个时辰,12个时辰中12条经脉交替运行,调节人体阴阳、脏腑... 目前乳腺癌的治疗方法主要以西医为主,中医为辅,两者相结合,往往能发挥出更好的疗效。但以往两者在运用上,又相对独立,唯独时间疗法可以贯穿所有治疗当中。一年有12个月,一天有12个时辰,12个时辰中12条经脉交替运行,调节人体阴阳、脏腑、经络的平衡。从中医理论来看,可以把时间看作佐助药,在乳腺癌的治疗中合理运用时间,或许可以提高乳腺癌的治疗效果及患者的生存质量。 展开更多
关键词 乳腺癌 时间 佐助药
A monotone finite volume method for time fractional Fokker-Planck equations
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作者 Yingjun Jiang Xuejun Xu 《中国科学:数学英文版》 SCIE CSCD 2019年第4期783-794,共12页
We develop a monotone finite volume method for the time fractional Fokker-Planck equations and theoretically prove its unconditional stability. We show that the convergence rate of this method is of order 1 in the spa... We develop a monotone finite volume method for the time fractional Fokker-Planck equations and theoretically prove its unconditional stability. We show that the convergence rate of this method is of order 1 in the space and if the space grid becomes suffciently fine, the convergence rate can be improved to order 2.Numerical results are given to support our theoretical findings. One characteristic of our method is that it has monotone property such that it keeps the nonnegativity of some physical variables such as density, concentration,etc. 展开更多
关键词 time FRACTIONAL FOKKER-PLANCK EQUATIONS FINITE volume methods MONOTONE CONVERGENCE
Residuals-Based Deep Least Square Support Vector Machine with Redundancy Test Based Model Selection to Predict Time Series
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作者 Yanhua Yu Jie Li 《清华大学学报自然科学版(英文版)》 EI CAS CSCD 2019年第6期706-715,共10页
In this paper, we propose a novel Residuals-Based Deep Least Squares Support Vector Machine(RBDLSSVM). In the RBD-LSSVM, multiple LSSVMs are sequentially connected. The second LSSVM uses the fitting residuals of the f... In this paper, we propose a novel Residuals-Based Deep Least Squares Support Vector Machine(RBDLSSVM). In the RBD-LSSVM, multiple LSSVMs are sequentially connected. The second LSSVM uses the fitting residuals of the first LSSVM as input time series, and the third LSSVM trains the residuals of the second, and so on. The original time series is the input of the first LSSVM. Additionally, to obtain the best hyper-parameters for the RBD-LSSVM, we propose a model validation method based on redundancy test using Omni-Directional Correlation Function(ODCF). This method is based on the fact when a model is appropriate for a given time series, there should be no information or correlation in the residuals. We propose the use of ODCF as a statistic to detect nonlinear correlation between two random variables. Thus, we can select hyper-parameters without encountering overfitting,which cannot be avoided by only cross validation using the validation set. We conducted experiments on two time series: annual sunspot number series and monthly Total Column Ozone(TCO) series in New Delhi. Analysis of the prediction results and comparisons with recent and past studies demonstrate the promising performance of the proposed RBD-LSSVM approach with redundancy test based model selection method for modeling and predicting nonlinear time series. 展开更多
关键词 time series prediction information REDUNDANCY residuals-based DEEP Least Squares Support Vector Machine (LSSVM) OMNI-DIRECTIONAL Correlation Function (ODCF)
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