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1
He, Mingyang. "Analysis of the Policymaking Process of Undergraduate Tutorial System in China from the Perspective of Multiple Streams Theory." BCP Social Sciences & Humanities 19 (August 30, 2022): 171–74. http://dx.doi.org/10.54691/bcpssh.v19i.1601.
Повний текст джерелаАнотація:
The formulation process of China's undergraduate tutor system involves many factors. Based on the perspective of multiple streams theory, this paper analyzes and discusses the driving factors for the establishment of China's undergraduate tutorial system policy agenda. Policy makers form the problem stream through surveys of students and teachers; the government and colleges, as policy entrepreneurs, shape the policy stream; under the China’s unique conditions, the educational philosophy of the Communist Party of China and the popularization of higher education develops into the politics stream. At a critical point, the three streams are coupled and the policy window opens, which eventually leads to the introduction of the undergraduate tutorial system. Additionally, this paper also analyzes the defects of the multiple stream’s theory, and puts forward suggestions for the revision of the theoretical model.
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Qin, Li, Peng Lixia, Liu Haidong, and Zhang Qi. "Research on Product Production Process Optimization Based on Value Stream Theory." Journal of Software Engineering 10, no. 1 (December 15, 2015): 89–98. http://dx.doi.org/10.3923/jse.2016.89.98.
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Vitali, Giuliano. "Runoff as a Stochastic Process." International Journal of Mathematics and Computers in Simulation 16 (March 8, 2022): 59–62. http://dx.doi.org/10.46300/9102.2022.16.9.
Повний текст джерелаАнотація:
Runoff stationary critical flow is investigated as a stochastic process by means of two routing simulation models, a stream confluence, which has beens interpreted as a Marcus- Lushnikov coalescence process, and a channel splitting model, which has ben interpreted as a Markov chain over a regular tree. Despite of the expected similarity due to expection that they should be seen as one the backward of the other, the initiation and the stopping methods using in algorithms influence strongly stream size distribution.
4
Ferreira da Silva, Ana Maria. "On the stable geometry of self-formed alluvial channels: theory and practical applicationThis article is one of a selection of papers in this Special Issue in honour of Professor M. Selim Yalin (1925–2007)." Canadian Journal of Civil Engineering 36, no. 10 (October 2009): 1667–79. http://dx.doi.org/10.1139/l09-013.
Повний текст джерелаАнотація:
On the basis of previous work by the late Professor M. Selim Yalin and the author, the process of self-formation of alluvial streams and the final (equilibrium or regime) geometry of the self-formed stream are considered in the light of thermodynamic principles, including the first and second laws, and the Gibb’s equation; the stream is treated as an isolated and irreversible system. The present analysis suggests that stream self-formation is guided by the need of the stream to progressively decrease its average flow velocity to accommodate the increase in the entropy of the system with the passage of time. The reduction in flow velocity is achieved by an appropriate alteration of stream slope, cross-sectional geometry, and effective roughness, the regime development being the process of this appropriate alteration. A method is presented for the computation of regime width, depth, and slope. The method rests on the channel formation criterion derived from thermodynamic principles and the expression of regime flow width determined on the basis of zero net cross sediment transport rate at the regime state. The regime channels computed from this method are compared with field and laboratory data from various sources.
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Wang, Zhongwen, Haozhu Lu, Junlan Jin, and Kai Hu. "Human Action Recognition Based on Improved Two-Stream Convolution Network." Applied Sciences 12, no. 12 (June 7, 2022): 5784. http://dx.doi.org/10.3390/app12125784.
Повний текст джерелаАнотація:
Two-stream convolution network (2SCN) is a classical method of action recognition. It is capable of extracting action information from two dimensions: spatial and temporal streams. However, the method of extracting motion features from a spatial stream is single-frame recognition, and there is still room for improvement in the perception ability of appearance coherence features. The classical two-stream convolution network structure is modified in this paper by utilizing the strong mining capabilities of the bidirectional gated recurrent unit (BiGRU) to allow the neural network to extract the appearance coherence features of actions. In addition, this paper introduces an attention mechanism (SimAM) based on neuroscience theory, which improves the accuracy and stability of neural networks. Experiments show that the method proposed in this paper (BS-2SCN, BiGRU-SimAM Two-stream convolution network) has high accuracy. The accuracy is improved by 2.6% on the UCF101 data set and 11.7% on the HMDB51 data set.
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Wang, Shuqiang, Jia Tang, Yiquan Zou, and Qihui Zhou. "Research on production process optimization of precast concrete component factory based on value stream mapping." Engineering, Construction and Architectural Management 27, no. 4 (November 4, 2019): 850–71. http://dx.doi.org/10.1108/ecam-10-2018-0455.
Повний текст джерелаАнотація:
Purpose The purpose of this paper is to investigate the process optimization of a precast concrete component production line by using value stream mapping. Design/methodology/approach This paper is an empirical focused on of lean production theory and value stream mapping. The data in the case study were collected in real time on-site for each process during the production process of a prefabricated exterior wall. Findings The results of the current value stream map indicate that the main problems of the current production process are related to equipment, technology and organization. The equipment problems include simple demolding and cleaning tools and the lack of professional transfer channels. The technology problems include the lack of a marking mechanism and pipeline exit mechanism. There is a lack of standard operating procedures and incomplete process convergence. A comparison and analysis of the current value stream and the future value flow indicate that optimizations of the process flow, the production line layout, and the standard operating procedures have shortened the delivery cycle, reduced the number of workers, improved the operator’s operating level and balanced the production line. Practical implications The results of this study provide practitioners with a clear understanding of the optimization of the precast concrete component production and represent a method and basis for the process optimization of a factory production line; the approach is suitable for process optimization in other areas. Originality/value This research represents an innovative application of lean production theory and value stream mapping in a complex production line of precast concrete components and thereby fills the gap between the theory and practice of the optimization of a precast concrete component production line.
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Su, He, Pei Wu, Jing Xue, Yongan Zhang, and Haijun Zhang. "Analysis of flow field characteristics and structure optimization of the split-stream rushing muffler for diesel engine." Noise Control Engineering Journal 68, no. 1 (January 20, 2020): 101–11. http://dx.doi.org/10.3397/1/37688.
Повний текст джерелаАнотація:
In order to analyze the flow field characteristics of the split-stream rushing muffler, a theoretical model describing the velocity of the split streams is established and verified by the tracer test. For this new-principle muffler, the acoustic performance and the relationship between the velocity drop of the airflow and the pressure field are analyzed, also the structure optimization of the muffler is carried out based on the orthogonal test. Finally, a new muffler is fabricated based on the designing theory of this type of muffler for a prototype of diesel engine, and the comparative analyses are conducted compared with its original muffler. The results show that the establishment and analysis of the theoretical model for velocity during the split-streams rushing process are correct. In the frequency range of 0â–“1000 Hz, the average transmission loss of split-stream rushing muffler is better than that of the original muffler. While the speed of airflow is reduced by split-streams rushing, a certain pressure loss is caused at the same time, which is about 50% of total pressure loss of the muffler, and the average fluid resistance coefficient of the split-stream rushing process is 0.91. Compared to the original muffler of the sample engine, the average insertion loss of the optimized new muffler is increased by 61.2%. At inlet air velocity of 30 m/s, the pressure loss is reduced by 16.8%. The results provide a potential for practical engineering application of this new split-stream rushing muffler in future.
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Sun, Wen Jie. "Research on Stream Cipher Model Based on Chaos Theory." Applied Mechanics and Materials 539 (July 2014): 321–25. http://dx.doi.org/10.4028/www.scientific.net/amm.539.321.
Повний текст джерелаАнотація:
Chaos is a similar and random process which is very sensitive to initial value in deterministic system. It is a performance of nonlinear dynamical system with built-in randomness. Combined with the advantages and disadvantages of the present chaos encryption model, the paper proposes a chaotic stream cipher model based on chaos theory, which not only overcomes finite precision effect, but also improves the randomness of chaotic system and output sequence. The Sequence cycle theory generated by the algorithm can reach more than 10600 at least, which completely satisfies the actual application requirements of stream cipher system.
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Pereira Librelato, Tatiane, Daniel Pacheco Lacerda, Luís Henrique Rodrigues, and Douglas Rafael Veit. "A process improvement approach based on the Value Stream Mapping and the Theory of Constraints Thinking Process." Business Process Management Journal 20, no. 6 (October 28, 2014): 922–49. http://dx.doi.org/10.1108/bpmj-07-2013-0098.
Повний текст джерелаАнотація:
Purpose – The purpose of this paper is to present a case of integration between the processes modeling by using the Value Stream Mapping (VSM) and the Thinking Process of the Theory of Constraints (TP-TOC) through the analysis of productive processes of an organization, indicating the complementary aspects between them and their benefits to the organization. Design/methodology/approach – The paper uses a company of the Brazilian automotive industry as the administering site. The research began by identifying the organization's processes and choice of a family of products to model according to the VSM approach. The integrated view between the losses in the process (VSM) and the unwanted effects of the adding value process were analyzed by using the Current Reality Tree. After the analysis, different improvement procedures are proposed based on the lean principles. Finally, a work plan is presented based on the previous steps aiming to achieve the proposed future state. Findings – The analysis of this case helps to understand and identify the causes of the current problems in the processes studied, providing an integrated view between the losses in the process and the prioritization of steps for the elimination of such losses. The approach in its initial administration was robust and the solution steps were promising. By integrating these approaches, it was possible to verify improvement opportunities by identifying the losses and the basic causes that sustain the unwanted effects in the processes at the same time. Originality/value – The study proposes an approach that enables a systematic and systemic analysis of the processes at organizations through the combined use of process modeling through the VSM and TP-TOC. Simultaneously, the losses in the processes and the unwanted effects are identified. Thus, through the construction of an effect-cause-effect robust logic, both losses in particular and the unwanted effects in general can be prioritized in order to maximize the improvement efforts in the processes.
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Carter, Sasha P., Helen A. Fricker, and Matthew R. Siegfried. "Antarctic subglacial lakes drain through sediment-floored canals: theory and model testing on real and idealized domains." Cryosphere 11, no. 1 (February 2, 2017): 381–405. http://dx.doi.org/10.5194/tc-11-381-2017.
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Abstract. Over the past decade, satellite observations of ice surface height have revealed that active subglacial lake systems are widespread under the Antarctic Ice Sheet, including the ice streams. For some of these systems, additional observations of ice-stream motion have shown that lake activity can affect ice-stream dynamics. Despite all this new information, we still have insufficient understanding of the lake-drainage process to incorporate it into ice-sheet models. Process models for drainage of ice-dammed lakes based on conventional R-channels incised into the base of the ice through melting are unable to reproduce the timing and magnitude of drainage from Antarctic subglacial lakes estimated from satellite altimetry given the low hydraulic gradients along which such lakes drain. We have developed an alternative process model, in which channels are mechanically eroded into the underlying deformable subglacial sediment. When applied to the known active lakes of the Whillans–Mercer ice-stream system, the model successfully reproduced both the inferred magnitudes and recurrence intervals of lake-volume changes, derived from Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data for the period 2003–2009. Water pressures in our model changed as the flood evolved: during drainage, water pressures initially increased as water flowed out of the lake primarily via a distributed system, then decreased as the channelized system grew, establishing a pressure gradient that drew water away from the distributed system. This evolution of the drainage system can result in the observed internal variability of ice flow over time. If we are correct that active subglacial lakes drain through canals in the sediment, this mechanism also implies that active lakes are typically located in regions underlain by thick subglacial sediment, which may explain why they are not readily observed using radio-echo-sounding techniques.
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Li, Huiyong, Xiaofeng Wu, and Yanhong Wang. "Dynamic Performance Analysis of STEP System in Internet of Vehicles Based on Queuing Theory." Computational Intelligence and Neuroscience 2022 (April 10, 2022): 1–13. http://dx.doi.org/10.1155/2022/8322029.
Повний текст джерелаАнотація:
The Internet of vehicles (IoV) is an important research area of the intelligent transportation systems using Internet of things theory. The complex event processing technology is a basic issue for processing the data stream in IoV. In recent years, many researchers process the temporal and spatial data flow by complex event processing technology. Spatial Temporal Event Processing (STEP) is a complex event query language focusing on the temporal and spatial data flow in Internet of vehicles. There are four processing models of the event stream processing system based on the complex event query language: finite automata model, matching tree model, directed acyclic graph model, and Petri net model. In addition, the worst-case response time of the event stream processing system is an important indicator of evaluating the performance of the system. Firstly, this paper proposed a core algorithm of the temporal and spatial event stream processing program based on STEP by Petri net model. Secondly, we proposed a novel method to estimate the worst-case response time of the event stream processing system, which is based on stochastic Petri net and queuing theory. Finally, through the simulation experiment based on queuing theory, this paper proves that the data stream processing system based on STEP has good dynamic performance in processing the spatiotemporal data stream in Internet of vehicles.
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Binsted, Gordon, and Les G. Carlton. "When is movement controlled by the dorsal stream?" Behavioral and Brain Sciences 25, no. 1 (February 2002): 97–98. http://dx.doi.org/10.1017/s0140525x02230022.
Повний текст джерелаАнотація:
Our commentary focuses on the functional link between the ventral and dorsal systems implied by Norman, as they relate to overt movement. While issues relating to space perception and size constancy are the primary justification for this dual-process theory, the philosophical extensions of this approach are less consistent with examination of motor control and, in particular, motor learning.
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Zhukovich, S. Ya. "Application of methods of system analysis for modeling the process of distance learning." «System analysis and applied information science», no. 2 (August 19, 2021): 64–67. http://dx.doi.org/10.21122/2309-4923-2021-2-64-67.
Повний текст джерелаАнотація:
A mathematical model of distance learning based on control theory in the form of an inhomogeneous linear differential equation is proposed. On the basis of the coefficients of assimilation and forgetting, determined with the help of special tests, it is possible to predict, in some approximation, the level of current knowledge of both the individual trainee and the group or stream of students.
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Hong, Chang-Yu. "Challenges and Achievements beyond Decision-Making Power of Planners: How Are Decisions on Planning for Stream Restoration Made in South Korea?" Water 12, no. 10 (September 27, 2020): 2708. http://dx.doi.org/10.3390/w12102708.
Повний текст джерелаАнотація:
This research covers existing planning theory and possible ways to improve the decision-making process in Korean stream restoration. First, it attempts to recognize what extent the Korean stream restoration case follows Western environmental decision-making models. Additionally, key concepts and factors of environmental decision-making are discussed to build a foundation of planning theory. This research reveals key works in the broad and changing field of stream restoration that provides the foundation for understanding Korean water resource planning. To recognize the challenges and achievements of this planning, this paper first notes that, while technical perspectives of the engineering field have historically dominated stream restoration, current thinking recognizes the much greater complexity of stream restoration requires more than only engineering perspectives. After reviewing the literature in related areas, this research considers what the planning field has to offer. In the conclusion, this author argues that the application of citizen-oriented decision-making approaches could lead to better water resource management. Admittedly, this may still be hindered by political uncertainty and power conflicts caused by science-dominant environmental planning.
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Hidayah, Arina Rohmatul. "Political Marketing of Stream by Candidates through Facebook in the 2018 Regional Election of East Java." Politicon : Jurnal Ilmu Politik 3, no. 1 (March 31, 2021): 1–33. http://dx.doi.org/10.15575/politicon.v3i1.9456.
Повний текст джерелаАнотація:
Previous researches on political marketing found several gaps in terms of content and essence as a process of political exchange and interaction. Based on this, the researcher aims to actualize the essence of the basic theory or concept of political marketing into the 2018 regional election of East Java through the use of social media as an interactive media. For the content aspect, researcher selected political stream as a society cultural system. It considered as one of the determining aspects for voter preferences, especially in East Java. Qualitative approach with the content analysis method conducted for this research by applying political marketing theories and the political stream concepts from Clifford Geertz. The result of this research revealed that political stream also revolves around the political elite. Each candidate tries to display some stream characteristics that are considered familiar by the public to increase redundancy or message certainty. In this case, Gus Ipul-Puti is considered to be stronger and more varied than Khofifah-Emil. However, from public reaction, not all of the political streams conveyed can be clearly captured by the users. This occurred because there are some cultural differences between the message sender and it’s receiver. Nevertheless, the implications of this research can be used as a benchmark of how to utilize political stream effectively in order to get a positive response from the public. Then, it also can be literacy medium to recognize the cultural symbols raised in political contestation in Indonesia.
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BRANDT, LUCA, and DAN S. HENNINGSON. "Transition of streamwise streaks in zero-pressure-gradient boundary layers." Journal of Fluid Mechanics 472 (November 30, 2002): 229–61. http://dx.doi.org/10.1017/s0022112002002331.
Повний текст джерелаАнотація:
A transition scenario initiated by streamwise low- and high-speed streaks in a flat-plate boundary layer is studied. In many shear flows, the perturbations that show the highest potential for transient energy amplification consist of streamwise-aligned vortices. Due to the lift-up mechanism these optimal disturbances lead to elongated streamwise streaks downstream, with significant spanwise modulation. In a previous investigation (Andersson et al. 2001), the stability of these streaks in a zero-pressure-gradient boundary layer was studied by means of Floquet theory and numerical simulations. The sinuous instability mode was found to be the most dangerous disturbance. We present here the first simulation of the breakdown to turbulence originating from the sinuous instability of streamwise streaks. The main structures observed during the transition process consist of elongated quasi-streamwise vortices located on the flanks of the low-speed streak. Vortices of alternating sign are overlapping in the streamwise direction in a staggered pattern. The present scenario is compared with transition initiated by Tollmien–Schlichting waves and their secondary instability and by-pass transition initiated by a pair of oblique waves. The relevance of this scenario to transition induced by free-stream turbulence is also discussed.
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Gao, Chong, Zhongjian Kang, and Xianghai Zhang. "Delay Correction for Pre-Breakdown Phase of Subsonic Stream Discharge in Water." Journal of Physics: Conference Series 2310, no. 1 (October 1, 2022): 012058. http://dx.doi.org/10.1088/1742-6596/2310/1/012058.
Повний текст джерелаАнотація:
Abstract Shock waves generated by streamer discharge in water have huge application value to improve unconventional reservoirs. In this paper, experiment platform for high-voltage pulse discharge in water, which beneficial to research the pre-breakdown phase of subsonic streamer discharge in water of high-frequency discharge application scenarios is established. The mechanism of stream discharge and the importance of polarization process were analysed by high voltage theory. The initial time of flow column development was determined based on the time-varying characteristics, and the time of pre-breakdown phase was corrected by using the lightning shock intercept analysis theory. The results show that the polarization process should be incorporated into the pre-breakdown phase. Meanwhile, the initial development time of the flow column is the 3μs of the experimental data. After modification, the polarization process is shortened by 0.9372μs and the delay correction ratio is 24.57% after modification.
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Williams, Daniel. "Transatlantic Climate and Gulf Stream Aesthetics." Nineteenth-Century Literature 76, no. 1 (June 1, 2021): 57–91. http://dx.doi.org/10.1525/ncl.2021.76.1.57.
Повний текст джерелаАнотація:
Daniel Williams, “Transatlantic Climate and Gulf Stream Aesthetics” (pp. 57–91) The Gulf Stream gained scientific prominence in the nineteenth century as a test case for theories about the dynamics of ocean currents and the equilibrium of transatlantic climate. Discourse about the current supplied descriptions, analogies, and myths that persist into the present. Triangulating oceanic, ecological, and transatlantic approaches to literary study, this essay argues that the nineteenth-century discourse of the Gulf Stream included a significant aesthetic dimension organized by a dialectic between stability and variability. First, the essay traces the Gulf Stream’s presence in eighteenth- and nineteenth-century scientific writing and print culture, showing how memorable figures and vivid illustrations accentuated the risk of climate variability even as they charted an apparently stable oceanic system. Next, it considers the work of two poets separated by the ocean, Gerard Manley Hopkins and Sidney Lanier. While ostensibly using the Gulf Stream motif to reflect on geographic identity and cultural belonging, Hopkins and Lanier use formal and figurative techniques that register the threat of climate instability, offering a deeper sense of climate disquiet than the scientific materials on which they drew. Finally, the essay looks at the poetry of Derek Walcott, sketching the afterlife of the Gulf Stream discourse, extending its formal and figurative lineage, and renewing the present ecological urgency of thinking with an Earth-system process as a motif of climatic connection and obligation.
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Schmied, Johannes, and Abbas Strømmen-Bakhtiar. "Situation Awareness Under Task Complexity." International Journal of Innovation in the Digital Economy 11, no. 4 (October 2020): 1–26. http://dx.doi.org/10.4018/ijide.2020100101.
Повний текст джерелаАнотація:
Performing tasks under task complexity (TC), for example, during the management of a crisis, can be challenging. One relevant research stream has so far dealt with modelling task complexity while another research stream has established the importance of situation awareness (SA) during crisis management. This study takes into consideration these two research streams and builds a model on how SA is achieved under task complexity. The research shows that information of high information quality (IQ) reduces the level of task complexity, and influences—as well as is influenced by—situation awareness. The practice of collecting and disseminating relevant and timely information as a critical resource in improving SA should be carried out continuously. This continuous process can be improved by using information technologies as automating tools. Moreover, the study shows how shared mental models can improve SA under task complexity. A case study approach, based on qualitative data focusing on theory building, is applied. Unit of analysis is a Norwegian hospital.
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Natsoulas, Thomas. "The Stream of Consciousness: XI. A Critique of James's Appendage Theory of Consciousness (Second Part)." Imagination, Cognition and Personality 16, no. 1 (September 1996): 63–82. http://dx.doi.org/10.2190/kcud-fdnm-rdyv-hbn1.
Повний текст джерелаАнотація:
In this two-part article, I discuss William James's account of inner awareness as it is expressed in The Principles of Psychology. Inner awareness is the immediate awareness which we all have of some of our own mental-occurrence instances. An essential part of what it is for a mental-occurrence instance to be conscious, or to be a state of consciousness, is an actual or potential immediate awareness of it. Appendage theories hold that inner awareness requires a distinct mental-occurrence instance that has the respective conscious mental-occurrence instance as its object. Intrinsic theories argue that every conscious mental-occurrence instance includes, in its own structure, awareness of itself. On James's account, it is the total brain process that normally brings into existence any mental-occurrence instance, or basic durational component of the stream of consciousness. And then, this brain process often produces a further component of the stream that gives immediate awareness of the first component.
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Веневитина, Svetlana Venevitina, Зеликов, Vladimir Zelikov, Уточкина, Elena Utochkina, Зеликова, and O. Zelikova. "USE OF MARKOV`S SUCCESSIONS IN DISTRIBUTION OF TRAF-FIC STREAM." Voronezh Scientific-Technical Bulletin 4, no. 1 (April 15, 2015): 4–14. http://dx.doi.org/10.12737/10888.
Повний текст джерелаАнотація:
For mathematic description of traffic stream use of mathematic apparatus, that is used in theory of probability for Markov`s random process. Use of Mar-kov`s successions allows to set a problem of determining the probability of find-ing the traffic stream in any condition, as well as beingwith the help of Kolmogo-rov`s equations finding the possibility of denial, the possibility of maintenance, as well as absolute carrying capacity of the system.
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Ding, Yu, Jianjun Shi, and Dariusz Ceglarek. "Diagnosability Analysis of Multi-Station Manufacturing Processes." Journal of Dynamic Systems, Measurement, and Control 124, no. 1 (October 9, 2001): 1–13. http://dx.doi.org/10.1115/1.1435645.
Повний текст джерелаАнотація:
Variation propagation in a multi-station manufacturing process (MMP) is described by the theory of “Stream of Variation.” Given that the measurements are obtained via certain sensor distribution scheme, the problem of whether the stream of variation of an MMP is diagnosable is of great interest to both academia and industry. We present a comprehensive study of the diagnosability of MMPs in this paper. It is based on the state space model and is parallel to the concept of observability in control theory. Analogous to the observability matrix and index, the diagnosability matrix and index are first defined and then derived for MMP systems. The result of diagnosability study is applied to the evaluation of sensor distribution strategy. It can also be used as the basis to develop an optimal sensor distribution algorithm. An example of a three-station assembly process with multi-fixture layouts is presented to illustrate the methodology.
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Carvalho Brito Souza, Acsa Liliane, and Prof Dr Ricardo Jorge da Cunha Costa Nogueira. "Study of the Applicability of the Restriction Theory and the Value Stream Mapping in the Management of Processes of the Legal Practice Nucleus of a Law Faculty in Rondônia, Brazil." International Journal for Innovation Education and Research 8, no. 6 (June 1, 2020): 154–66. http://dx.doi.org/10.31686/ijier.vol8.iss6.2385.
Повний текст джерелаАнотація:
This article aims to discuss, based on the researcher’s observation during the years 2017 to 2019, about the flow of lawsuits from a Legal Practice Nucleus of a law faculty, in the city of Porto Velho, Rondônia, Brazil, highlighting the lawsuits of the family court, because these processes need urgency and usually take time in the elaboration of their pieces. This research will present a study on how the Value Stream Mapping and the Restriction Theory help to decrease or eliminate time losses in the process of this NPJ. For the development, used an analytical literature review methodology on the Restriction Theory and Value Stream Mapping. The research subjects were the agents involved in the activities of the NPJ and the data collected by the participant’s observation method.
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Merkus, Sander, and Marcel Veenswijk. "Turning New Public Management theory into reality: Performative struggle during a large scale planning process." Environment and Planning C: Politics and Space 35, no. 7 (January 18, 2017): 1264–84. http://dx.doi.org/10.1177/0263774x16689370.
Повний текст джерелаАнотація:
Within the literature of governance and policy making in the context of planning, the notion of performativity is specifically conceptualized as the self-fulfilling property of performances – such as story-telling – that shape public reality. One specific stream of performativity researchers – dominant in the realm of organization studies – focuses on the enactment of academic theory into reality. We contribute to this idea of bringing theory into being by conceptualizing purposive performative agents who strive to enact a specific theory in reality. Our paper demonstrates through which mechanisms the theory of New Public Management has shaped the reality of public governance at the will of one powerful performative agent. Using a perspective based on performative struggle, our interpretative case study – focused on a large policy process – exhibits how New Public Management doctrine gains influence at the expense of other public management theories. In conclusion, we claim that our findings offer a potential perspective for understanding through which dynamics certain agents aim to shape the public realm in alignment with their preferred theoretical propositions.
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Doretto, Alberto, Elena Piano, and Courtney E. Larson. "The River Continuum Concept: lessons from the past and perspectives for the future." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 11 (November 2020): 1853–64. http://dx.doi.org/10.1139/cjfas-2020-0039.
Повний текст джерелаАнотація:
The River Continuum Concept (RCC) is a milestone in stream ecology because of its comprehensive evaluation of the structure and function of lotic ecosystems. Linking stream physical and geomorphological attributes with patterns in biodiversity, functional traits, and metabolism dynamics, this theory describes downstream gradients in community composition and ecosystem processes. The aim of this review is to evaluate how the RCC, 40 years from its publication in the Canadian Journal of Fisheries and Aquatic Sciences, has influenced basic and applied research in stream ecology, focusing on the most important contributions and recent developments. This work puts into perspective the historical importance of the RCC in the scientific process and integrates past and recent theories, including metacommunity and metaecosystem theories and the river network perspective, to predict taxonomic and functional diversity of benthic communities. Thus, this review provides a unifying overview of the historical context of the field for exploring basic and applied ecological questions to the next generation of stream ecologists.
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Ferone, Alessio, and Antonio Maratea. "Adaptive Quick Reduct for Feature Drift Detection." Algorithms 14, no. 2 (February 11, 2021): 58. http://dx.doi.org/10.3390/a14020058.
Повний текст джерелаАнотація:
Data streams are ubiquitous and related to the proliferation of low-cost mobile devices, sensors, wireless networks and the Internet of Things. While it is well known that complex phenomena are not stationary and exhibit a concept drift when observed for a sufficiently long time, relatively few studies have addressed the related problem of feature drift. In this paper, a variation of the QuickReduct algorithm suitable to process data streams is proposed and tested: it builds an evolving reduct that dynamically selects the relevant features in the stream, removing the redundant ones and adding the newly relevant ones as soon as they become such. Tests on five publicly available datasets with an artificially injected drift have confirmed the effectiveness of the proposed method.
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Druzhinin, O. A., V. I. Kazakov, P. A. Matusov, and L. A. Ostrovsky. "The evolution of a thermocline effected by a turbulent stream." Nonlinear Processes in Geophysics 2, no. 1 (March 31, 1995): 49–57. http://dx.doi.org/10.5194/npg-2-49-1995.
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Abstract. The process of thermocline evolution under the action of turbulent stream in the upper layer is investigated in laboratory experiment in thermally stratified tank, the initial temperature profile with pronounced thermocline being similar to that observed in tropic seas. The mean velocity and turbulent energy spatial distributions have been shaped to model the hydrological conditions in strong oceanic currents or wind-induced drag currents. The experiment demonstrates the gradual deepening and transformation of thermocline in a case where no global instability took place (i.e., with Richardson numbers always exceeding 0.3-0.4). The process of thermocline evolution resulted also in recurring "bursts" of microstructure. A numerical experiment based on equations of semi-empirical theory of turbulence shows quantitative agreement with experimental data. Moreover, simple analytical solutions and numerical results show that a layer with marginal stability is formed with Richardson numbers being very close to the stability threshold, so that quite small disturbances in thermocline can result in appearance of internal waves and bursts of turbulence.
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Brodie, Roderick J., and Linda D. Peters. "New directions for service research: refreshing the process of theorizing to increase contribution." Journal of Services Marketing 34, no. 3 (May 7, 2020): 415–28. http://dx.doi.org/10.1108/jsm-01-2019-0048.
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Purpose For service research to develop as an applied social science there is the need to refresh the process of theorizing so it focuses not only on increasing new academic knowledge but also on knowledge that is managerially relevant. This paper aims to provide guidelines to achieve this. Design/methodology/approach A theorizing process that integrates general theoretic perspectives and contextual research to develop midrange theory is developed. The process is based on the philosophical foundations of pragmatism and abductive reasoning, which has the origins in the 1950s when the management sciences were being established. Findings A recent research stream that develops midrange theory about customer and actor engagement is used to illustrate the theorizing process. Practical implications Practicing managers, customers and other stakeholders in a service system use theory, so there is a need to focus on how theory is used in specific service contexts and how this research leads to academic knowledge that is managerially relevant. Thus, as applied social science, service research needs to explicitly focus on bridging the theory–praxis gap with midrange theory by incorporating a general theoretic perspective and contextual research. Originality/value The contribution comes from providing a broader framework to guide the theorizing process that integrates general theoretic perspectives and applied research to develop midrange theory. While general theories operate at the most abstract level of conceptualization, midrange theories are context-specific and applied theory (theories-in-use) is embedded in empirical research.
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Woollard, David. "Towards a Theory of University Entrepreneurship." Industry and Higher Education 24, no. 6 (December 2010): 413–27. http://dx.doi.org/10.5367/ihe.2010.0017.
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This paper sets out to develop a robust theory in a largely atheoretical field of study. The increasing importance of entrepreneurship in delivering the ‘Third Mission’ calls for an enhanced understanding of the university entrepreneurship phenomenon, not solely as a subject of academic interest but also to guide the work of practitioners in the field. By adopting a systematic approach to theory building, a model has been derived by integrating theoretical conjectures from corporate entrepreneurship and university entrepreneurship literature. The integrated theoretical model developed locates university entrepreneurship as an organizational process in an entrepreneurial system depicted as an input-process-output model. Characterizations of the entrepreneurial process and system conditions that would justify an institution being classified as an entrepreneurial university are proposed; and the inter-relationships between the system, the system components and moderators of the effectiveness of the system are outlined. The integrated theory described in this paper contributes to academic knowledge and understanding of university entrepreneurship and, equally importantly, presents a model and relationships that can be useful to third-stream practitioners and senior institutional managers. The paper is among the first to derive systematically a theoretical construct for creating and sustaining university entrepreneurship. It should help to stimulate a debate that might add clarity to an increasingly important field of organizational development.
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Sirbiladze, Gia, Irina Khutsishvili, Otar Badagadze, and Mikheil Kapanadze. "More Precise Decision-Making Methodology in the Temporalized Body of Evidence. Application in the Information Technology Management." International Journal of Information Technology & Decision Making 15, no. 06 (November 2016): 1469–502. http://dx.doi.org/10.1142/s0219622016500371.
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In this paper, we perform the analysis of temporalized structure of a body of evidence and possibilistic Extremal Fuzzy Dynamic System (EFDS) for the construction of more precise decisions based on the expert knowledge stream. The process of decision precision consists of two stages. In the first stage the relation of information precision is defined on a monotone sequence of bodies of evidence. The principle of negative imprecision is developed, as the maximum principle of knowledge ignorance measure of a body of evidence. Corresponding mathematical programming problem is constructed. On the output of the first stage we receive the expert knowledge precision stream of the criteria with respect to any decision. In the second stage the constructed stream is an input trajectory for the finite possibilistic model of EFDS. A genetic algorithm approach is developed for identifying of the EFDS finite model. The modelling process gives us the more precise decisions as a prediction of a temporalization procedure. The constructed technology is applied in the non-probabilistic utility theory for the information technology management problem.
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Mejia, Cynthia, and Edwin N. Torres. "Implementation and normalization process of asynchronous video interviewing practices in the hospitality industry." International Journal of Contemporary Hospitality Management 30, no. 2 (February 12, 2018): 685–701. http://dx.doi.org/10.1108/ijchm-07-2016-0402.
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Purpose Asynchronous video interviews (AVIs) enable recruiters and job candidates to conduct and review employment interviews at different points in time, promising improved cost and time efficiencies for all users. This research aims to investigate the implementation and normalization process of AVI in the hospitality industry with the unified theory of acceptance and use of technology (UTAUT) and the normalization process theory (NPT) providing theoretical support. Design/methodology/approach Semi-structured interviews have been conducted with hiring managers from three different hospitality companies, which were in different stages of the implementation process. The data have been recorded, transcribed and coded according to the UTAUT and NPT constructs, revealing emergent themes. Findings Five overarching themes emerged: AVI effort and efficiency expectation; augmentation to the interview process; challenges for the applicant; challenges for the recruiter; and issues with applicant interviewing aesthetics. Additional coding and analysis with NPT identified the following in terms of evaluation of the implementation process: participants’ implementation activities showed a tendency to emanate from cognitive participation (relationship work), leading to coherence (sense-making work), followed by collective action (enactment of work/operational work) and finally reflexive monitoring (appraisal work). Practical implications Findings from this research include recommendations for the best practices integrating AVI into the hospitality employee selection process. Originality/value Given the increased demands on the recruitment and selection of talent in the hospitality industry, several organizations have turned to mechanized HR software platforms. The impact of interview modalities and particularly AVI has received limited research attention, thus this study expanded this new stream of literature. Furthermore, this research is among a nascent stream using NPT to evaluate the implementation and normalization of this new technology.
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Gula, Jonathan, M. Jeroen Molemaker, and James C. McWilliams. "Submesoscale Cold Filaments in the Gulf Stream." Journal of Physical Oceanography 44, no. 10 (October 1, 2014): 2617–43. http://dx.doi.org/10.1175/jpo-d-14-0029.1.
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Abstract A set of realistic, very high-resolution simulations is made for the Gulf Stream region using the oceanic model Regional Oceanic Modeling System (ROMS) to study the life cycle of the intense submesoscale cold filaments that form on the subtropical gyre, interior wall of the Gulf Stream. The surface buoyancy gradients and ageostrophic secondary circulations intensify in response to the mesoscale strain field as predicted by the theory of filamentogenesis. It can be understood in terms of a dual frontogenetic process, along the lines understood for a single front. There is, however, a stronger secondary circulation due to the amplification at the center of a cold filament. Filament dynamics in the presence of a mixed layer are not adequately described by the classical thermal wind balance. The effect of vertical mixing of momentum due to turbulence in the surface layer is of the same order of magnitude as the pressure gradient and Coriolis force and contributes equally to a so-called turbulent thermal wind balance. Filamentogenesis is disrupted by vigorous submesoscale instabilities. The cause of the instability is the lateral shear as energy production by the horizontal Reynolds stress is the primary fluctuation source during the process; this contrasts with the usual baroclinic instability of submesoscale surface fronts. The filaments are lines of strong oceanic surface convergence as illustrated by the release of Lagrangian parcels in the Gulf Stream. Diabatic mixing is strong as parcels move across the filaments and downwell into the pycnocline. The life cycle of a filament is typically a few days in duration, from intensification to quasi stationarity to instability to dissipation.
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Przekop, Rafał. "Estimation of Filtration Efficiency – from Simple Correlations to Digital Fluid Dynamics." Chemical and Process Engineering 38, no. 1 (March 1, 2017): 31–50. http://dx.doi.org/10.1515/cpe-2017-0004.
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AbstractAerosol filtration in fibrous filters is one of the principal methods of accurate removal of particulate matter from a stream of gas. The classical theory of depth filtration of aerosol particles in fibrous structures is based on the assumption of existing single fibre efficiency, which may be used to recalculate the overall efficiency of entire filter. Using “classical theory” of filtration one may introduce some errors, leading finally to a discrepancy between theory and experiment. There are several reasons for inappropriate estimation of the single fibre efficiency: i) neglecting of shortrange interactions, ii) separation of inertial and Brownian effects, ii) perfect adhesion of particles to the fibre, iv) assumption of perfect mixing of aerosol particles in the gas stream, v) assumption of negligible effect of the presence of neighbouring fibres and vi) assumption of perpendicular orientation of homogenous fibres in the filtration structure. Generally speaking, “classical theory” of filtration was used for characterization of the steady - state filtration process (filtration in a clean filter, at the beginning of the process) without deeper investigation of the influence of the nternal structure of the filter on its performance. The aim of this review is to outline and discuss the progress of deep-bed filtration modelling from the use of simple empirical correlations to advanced techniques of Computational Fluid Dynamics and Digital Fluid Dynamics.
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Galičić, Vlado. "Reengineering in business functions and hotel controlling." Tourism and hospitality management 2, no. 1 (July 15, 1996): 113–20. http://dx.doi.org/10.20867/thm.2.1.11.
Повний текст джерелаАнотація:
Business reengineering as a new stream in philosophy in managerial theory and practice, deserves appropriate attention. Such request sounds extremely natural when an hotel industry is concerned. Employing positive aims in business reengineering and controlling, as a way of modern management in a hotel business process, hotel management achieves valuable possibilities to gain better business results.
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Hu, Liang, Rui Sun, Feng Wang, Xiuhong Fei, and Kuo Zhao. "A Stream Processing System for Multisource Heterogeneous Sensor Data." Journal of Sensors 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/4287834.
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With the rapid development of the Internet of Things (IoT), a variety of sensor data are generated around everyone’s life. New research perspective regarding the streaming sensor data processing of the IoT has been raised as a hot research topic that is precisely the theme of this paper. Our study serves to provide guidance regarding the practical aspects of the IoT. Such guidance is rarely mentioned in the current research in which the focus has been more on theory and less on issues describing how to set up a practical system. In our study, we employ numerous open source projects to establish a distributed real time system to process streaming data of the IoT. Two urgent issues have been solved in our study that are (1) multisource heterogeneous sensor data integration and (2) processing streaming sensor data in real time manner with low latency. Furthermore, we set up a real time system to process streaming heterogeneous sensor data from multiple sources with low latency. Our tests are performed using field test data derived from environmental monitoring sensor data collected from indoor environment for system validation. The results show that our proposed system is valid and efficient for multisource heterogeneous sensor data integration and streaming data processing in real time manner.
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DIETZ, A. J. "Local boundary-layer receptivity to a convected free-stream disturbance." Journal of Fluid Mechanics 378 (January 10, 1999): 291–317. http://dx.doi.org/10.1017/s0022112098003243.
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An investigation of the local receptivity of a Blasius boundary layer to a harmonic vortical disturbance is presented as a step towards understanding boundary-layer receptivity to free-stream turbulence. Although there has been solid experimental verification of the linear theory describing acoustic receptivity of boundary layers, this was the first experimental verification of the mechanism behind local receptivity to a convected disturbance. The harmonic wake from a vibrating ribbon positioned upstream of a flat plate provided the free-stream disturbance. Two-dimensional roughness elements on the surface of the plate acted as a local receptivity site. Hot-wire measurements in the boundary layer downstream of the roughness confirmed the generation of Tollmien–Schlichting (TS) instability waves by an outer-layer interaction between the long-wavelength convected disturbance and the short-scale mean-flow distortion due to the roughness. The characteristics of the instability waves were carefully measured to ensure that their behaviour was correctly modelled by linear stability theory. This theory was then used to determine the immeasurably small initial wave amplitudes resulting from the receptivity process, from wave amplitudes measured downstream. Tests were performed to determine the range of validity of the linear assumptions made in current receptivity theories. Experimental data obtained in the linear regime were then compared to theoretical results of other authors by expressing the experimental data in the form of an efficiency function which is independent of the free-stream amplitude, roughness height and roughness geometry. Reasonable agreement between the experimental and theoretical efficiency functions was obtained over a range of frequencies and Reynolds numbers.
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Chang, C. M., and H. D. Yeh. "Variability of flow discharge in lateral inflow-dominated stream channels." Hydrology and Earth System Sciences 19, no. 5 (May 27, 2015): 2505–11. http://dx.doi.org/10.5194/hess-19-2505-2015.
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Abstract. The influence of the temporal changes in lateral inflow rate on the discharge variability in stream channels is explored through the analysis of the diffusion wave equation (i.e. the linearized Saint-Venant equation). To account for variability and uncertainty, the lateral inflow rate is regarded as a temporal random function. On the basis of the spectral representation theory, analytical expressions for the covariance function and evolutionary power spectral density of the random discharge perturbation process are derived to quantify variability in stream flow discharge induced by the temporal changes in lateral inflow rate. The treatment of the discharge variance (square root of the variance) gives us a quantitative estimate of uncertainty in predictions from the deterministic model. It is found that the discharge variability of stream flow is very large in the downstream reach, indicating large uncertainty anticipated from the use of the deterministic model. A larger temporal correlation scale of inflow rate fluctuations, representing more temporal consistency of fluctuations in inflow rate around the mean, introduces a higher variability in stream flow discharge.
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Cheng, Gaojie, Jianmo Liu, Jianfeng Xu, and Xiqiu Wang. "Dynamic Online learning Algorithm For Three-way decision." MATEC Web of Conferences 232 (2018): 03024. http://dx.doi.org/10.1051/matecconf/201823203024.
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Three-way decision is an important theory for solving uncertain problems. Online computing is a new dynamic Stream computing form. How to execute three-way decision quickly in online computing is a challenging topic. In this paper, Online computing process is divided into incremental computing portion and decreasing computing portion. And a three-way decision dynamic incremental and decreasing learning algorithm for online computing is proposed. Firstly, the dynamic incremental and decreasing learning models is studied for stream computing based on probabilistic rough set . Then, the logical reasoning for three-way decision regions changing are discussed based on the dynamic incremental and decreasing learning models. And a novel dynamic online learning algorithm for three-way decision online computing is proposed based on the above theory. Finally, the experiment by UCI data set show that the proposed algorithms are superior than classical static three-way decision method in time efficiency.
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Williams, Don, and Peter D. Burns. "Refining the Theory-to-Practice Path for FADGI Still Imaging." Archiving Conference 2020, no. 1 (April 7, 2020): 39–42. http://dx.doi.org/10.2352/issn.2168-3204.2020.1.0.39.
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The Digital Production Lab in John C. Hodges Library at the University of Tennessee, like many university imaging studios, has long relied on a seasonal and temporary labor force drawn from our student body. Improving human-computer interaction in our production workflows should reduce training time and errors while increasing throughput and worker confidence. In this paper, we present our on-going efforts adapting Elgato's Stream Deck XL hardware to control a computer running Apple's macOS operating system and Phase One's Capture One Pro software using Python and AppleScript code. The paper outlines our custom code linking these parts together, describes how this relatively inexpensive input device streamlines our digitization process, and includes ideas for future application.
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Edaibat, Omar. "Muḥyī l-Dīn Ibn ʿArabī’s Personalist Theory of the Sharīʿa". Journal of Sufi Studies 6, № 1 (6 липня 2017): 1–46. http://dx.doi.org/10.1163/22105956-12341294.
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While Ibn ʿArabī (d. 638/1240) continues to receive much attention within the academe as a preeminent Sufi philosopher, his jurisprudence, by contrast, rarely elicits the same attention, despite the prominent mention of the Sharīʿa throughout his many works. This paper provides an exhaustive overview of his sophisticated legal doctrine in terms of his legal methodology and substantive law. An analysis of his legal epistemology would situate him within the ‘scripturalist’ stream of legal theorists, commonly associated with the Zāhiri school. However, while Ibn Ḥazm (d. 456/1064) certainly influenced Ibn ʿArabī’s legal doctrine, the Shaykh’s jurisprudence remains markedly original in that it is ultimately rooted in an overarching metaphysical doctrine. This is evident in his personal reframing of ijtihād as a personal process of spiritual refinement, as opposed to a methodical process of ratiocination, which leads him to develop a distinctively personalist theory of legal pluralism that transcends the limitations of school conformity.
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Chung-Hua, Wu, Zhao Xiaolu, and Qin Lisen. "Three-Dimensional Rotational Flow in Transonic Turbomachines: Part II—Full Three-Dimensional Flow in CAS Rotor Obtained by Using a Number of S1 and S2 Stream Filaments." Journal of Turbomachinery 114, no. 1 (January 1, 1992): 50–60. http://dx.doi.org/10.1115/1.2927997.
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The general theory for three-dimensional flow in subsonic and supersonic turbo-machines has recently been extended to transonic turbomachines. In this paper, which is Part II of the study, quasi- and full three-dimensional solutions of the transonic flow in the CAS rotor are presented. The solutions are obtained by iterative calculation between a number of S1 stream filaments and, respectively, a central S2m Stream filament and a number of S2 stream filaments. Relatively simple methods developed recently for solving the transonic flow along S1 and S2 stream filaments are used in the calculation. The three-dimensional flow fields in the CAS rotor obtained by the present method are presented in detail with special emphasis on the converging process for the configuration of the S1 and S2 stream filaments. The three-dimensional flow fields obtained in the quasi- and full three-dimensional solutions are quite similar, but the former gives a lower peak Mack number and a smaller circumferential variation in Mach number than the latter. A comparison between the theoretical solution and the Laser-2-Focus measurement shows that the character of the transonic flow including the three-dimensional shock structure is in good agreement, but the measured velocity is slightly higher than the calculated one over most of the flow field.
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Chang, C. M., and H. D. Yeh. "Technical Note: Variability of flow discharge in lateral inflow-dominated stream channels." Hydrology and Earth System Sciences Discussions 12, no. 2 (February 25, 2015): 2477–95. http://dx.doi.org/10.5194/hessd-12-2477-2015.
Повний текст джерелаАнотація:
Abstract. The influence of the temporal changes in lateral inflow rate on the discharge variability in stream channels is explored through the analysis of diffusion wave equation (the linearized St. Venant equations). To account for variability and uncertainty, the lateral inflow rate is regarded as a temporal random function. Based on the spectral representation theory, analytical expressions for the covariance function and evolutionary power spectral density of the random discharge perturbation process are derived to quantify variability in stream flow discharge induced by the temporal changes in lateral inflow rate. Upon evaluating the closed-form expressions, it is found that the variability in stream flow discharge increases with distance from the upstream boundary of the channel and time as well. The temporal correlation scale of inflow rate fluctuations plays a positive role in enhancing the variability of the flow discharge in channels. The treatment of the discharge variance gives us a quantitative estimate of uncertainty from the use of the deterministic model.
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Magomedova, M. R. "CALCULATION MODEL OF SOLID PARTICLES MOTION IN NATURAL TURBULENT FLOWS." Herald of Dagestan State Technical University. Technical Sciences 46, no. 2 (August 28, 2019): 98–107. http://dx.doi.org/10.21822/2073-6185-2019-46-2-98-107.
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Objectives Improving the model of movement of solid particles in natural turbulent flows.Method The improvement of knowledge about the structure of water flows and the nature of channel processes has led to the development of views on sediment movement as a stochastic process due to the random nature of the factors causing it: natural-climatic and hydrological conditions, variability of the physical and mechanical properties of soils, and turbulence of water streams. In this regard, the methods of probability theory and the theory of random processes were used to construct the model of sediment movement.Result Based on the studies, a mathematical model of the reformation of natural channels was established by an unsteady flow, which provides a more complete, in comparison with existing domestic and foreign counterparts, consideration of factors affecting the flow of channel-forming sediments. The analysis of mathematical models of the movement of solid particles in the water stream showed that the physical nature of the transport of channel-forming sediments is more consistent with the model based on the parameters of the trajectories of solid particles, namely, lengths, heights and transport time (jumps) of bottom and suspended sediments and their concentration in the stream. Such a model is implemented by integrating averaged equations and vortex formations using a mathematical apparatus.Conclusion The calculated model of the movement of solid particles is implemented in the algorithmic language Fortran Power Station and tested on the basis of field and experimental studies in a wide range of hydraulic flow characteristics and physical and mechanical characteristics of channel soils.
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Wang, Liu Yan, You Peng Xu, and Ming Jing Yu. "River System Connectivity Analysis of Wuxi’s Central Urban Area Based on Graph Theory." Applied Mechanics and Materials 212-213 (October 2012): 543–48. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.543.
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Wuxi City is located in the hinterland of Taihu Basin and an important city in Yangtze River Delta Region with a prosperous economy. In the process of urban development, the river system pattern changes a lot. It has an impact on water environment, water ecology and other fields. The central urban area of Wuxi City was selected as the study area. Based on the river system of three periods: 1960s, 1980s and 2009, the rivers were classified into three levels according to the width of channels. The length, acreage and stream structure parameters were calculated. Then from the view of Graph Theory, river system was expressed as network graph, and the vertices, edges and degree of vertices were analyzed. The results show that the changes of rivers of different levels and lakes are not completely the same, but still appear a decreasing trend in general. The river network density and water surface ratio become smaller. Also the complexity and structure stability of river network weaken. The conclusions that the river evolution tends to be trunk and single, the stream structure is simplified and the connectivity of rivers and lakes reduces are verified by the analysis based on Graph Theory as well.
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ANCEY, C., A. C. DAVISON, T. BÖHM, M. JODEAU, and P. FREY. "Entrainment and motion of coarse particles in a shallow water stream down a steep slope." Journal of Fluid Mechanics 595 (January 8, 2008): 83–114. http://dx.doi.org/10.1017/s0022112007008774.
Повний текст джерелаАнотація:
We investigate the entrainment, deposition and motion of coarse spherical particles within a turbulent shallow water stream down a steep slope. This is an idealization of bed-load transport in mountain streams. Earlier investigations have described this kind of sediment transport using empirical correlations or concepts borrowed from continuum mechanics. The intermittent character of particle transport at low-water discharges led us to consider it as a random process. Sediment transport in this regime results from the imbalance between entrainment and deposition of particles rather than from momentum balance between water and particles. We develop a birth–death immigration–emigration Markov process to describe the particle exchanges between the bed and the water stream. A key feature of the model is its long autocorrelation times and wide, frequent fluctuations in the solid discharge, a phenomenon never previously explained despite its ubiquity in both nature and laboratory experiments. We present experimental data obtained using a nearly two-dimensional channel and glass beads as a substitute for sediment. Entrainment, trajectories, and deposition were monitored using a high-speed digital camera. The empirical probability distributions of the solid discharge and deposition frequency were properly described by the theoretical model. Experiments confirmed the existence of wide and frequent fluctuations of the solid discharge, and revealed the existence of long autocorrelation time, but theory overestimates the autocorrelation times by a factor of around three. Particle velocity was weakly dependent on the fluid velocity contrary to the predictions of the theoretical model, which performs well when a single particle is moving. For our experiments, the dependence of the solid discharge on the fluid velocity is entirely controlled by the number of moving particles rather than by their velocity. We also noted significant changes in the behaviour of particle transport when the bed slope or the water discharge was increased. The more vigorous the stream was, the more continuous the solid discharge became. Moreover, although 90% of the energy supplied by gravity to the stream is dissipated by turbulence for slopes lower than 10%, particles dissipate more and more energy when the bed slope is increased, but surprisingly, the dissipation rate is nearly independent of fluid velocity. A movie is available with the online version of the paper.
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D'Angelo, Donna J., Judy L. Meyer, Leslie M. Howard, Stanley V. Gregory, and Linda R. Ashkenas. "Ecological uses for genetic algorithms: predicting fish distributions in complex physical habitats." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 9 (September 1, 1995): 1893–908. http://dx.doi.org/10.1139/f95-782.
Повний текст джерелаАнотація:
Genetic algorithms (GA) are artificial intelligence techniques based on the theory of evolution that through the process of natural selection evolve formulae to solve problems or develop control strategies. We designed a GA to examine relationships between stream physical characteristics and trout distribution data for 3rd-, 5th-, and 7th-order stream sites in the Cascade Mountains, Oregon. Although traditional multivariate statistical techniques can perform this particular task, GAs are not constrained by assumptions of independence and linearity and therefore provide a useful alternative. To help gauge the effectiveness of the GA, we compared GA results with results from proportional trout distributions and multiple linear regression equations. The GA was a more effective predictor of trout distributions (paired t test, P < 0.05) than other methods and also provided new insights into relationships between stream geomorphology and trout distributions. Most importantly, GA equations emphasized the nonindependence of stream channel units by revealing that (i) the factors that influence trout distributions change along a downstream continuum, and (ii) channel unit sequence can be critical. Superior performance of the GA, along with the new information it provided, indicates that genetic algorithms may provide a useful alternative or supportive method to statistical techniques.
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Djurdjanovic, Dragan, and Jun Ni. "Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining." Journal of Manufacturing Science and Engineering 125, no. 4 (November 1, 2003): 716–30. http://dx.doi.org/10.1115/1.1621424.
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Machining processes are usually multi-station processes involving a large number of operations and several locating datum changes. Machining errors are thus introduced, transformed and accumulated as the workpiece is being machined. This paper introduces procedures for expressing the influence of errors in fixtures, locating datum features and measurement datum features on dimensional errors in machining. These procedures are essential in the derivation of the Stream of Variation model of dimensional machining errors using the CAD/CAPP parameters of the machining process. The linear state space form of the Stream of Variation model allows for advanced control theory achievements to be employed in formal solutions to problems in multi-station machining. Modeling procedures presented in this paper were experimentally verified in machining of an automotive cylinder head.
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Shen, Lin, and Lai Jun Liu. "Research on Alignment Error of Cable-Stayed Bridge Based on Stream of Variation." Applied Mechanics and Materials 178-181 (May 2012): 2439–43. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.2439.
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Based on the model of discrete-time linear systems, the paper builds up the state space model of cantilever assembly method by studying the stream of variation theory. To address the problem of evaluation in alignment error, the evolution index of comprehensive stability is presented after comparing the advantage and disadvantage of evaluation index of point stability and evaluation index of slope stability. The method of evolution index of comprehensive stability is demonstrated by evaluating the alignment error of a long-span cable-stayed bridge, and it can accurately evaluate the error of assembly process.
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Agbormbai, James, Weidong Zhu, and Liang Li. "Vortex Ring Theory—An Alternative to the Existing Actuator Disk and Rotating Annular Stream Tube Theories." Applied Sciences 11, no. 14 (July 17, 2021): 6576. http://dx.doi.org/10.3390/app11146576.
Повний текст джерелаАнотація:
Currently, the actuator disk theory (ADT) and the rotating annular stream-tube theory (RAST), both of which predicate on the axial momentum and generalized momentum theories, among others, are commonly used in investigating the aerodynamic characteristics of horizontal axis wind turbines (HAWTs). These theories, which are based on a rotor with an infinite number of blades, typically do not properly capture the flow physics of wind blowing past the rotors of HAWTs. A vortex ring theory (VRT) that analyzes HAWTs based solely on the characteristics of fluids flowing past obstructions is proposed. The VRT is not predicated on the assertion that the induced velocity in the wake is twice the induced velocity at the rotor. On the contrary, it splits the axial induction factor in the wake into two components, namely, the induction or interference factor due to the solidity of the rotor and the induction factor due to the wake of the rotor aw; aw and its azimuthal counterpart are determined using the Biot–Savart law. The pressure differences across the rotor segments of a HAWT are derived from the Bernoulli equation for all the three theories. Blade segment/local areas based on the blade sectional geometry of the rotor are used in the case of the VRT to estimate the local forces. All the calculations in this study are based on the design parameters of the 5MW National Renewable Energy Laboratory’s reference offshore wind turbine. Pressure differences are plotted as functions of local radii using the calculated axial and azimuthal induction factors for each theory. The local power coefficient is plotted as a function of the local tip-speed ratio, while the local thrust coefficient is plotted as a function of the local radii for all the three theories. There is piece-wise agreement between the VRT, the ADT, the RAST and numerical and experimental data available in the literature.
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Chen, Jing, Chenguang Xiao, and Dan Chen. "Connectivity Evaluation and Planning of a River-Lake System in East China Based on Graph Theory." Mathematical Problems in Engineering 2018 (July 18, 2018): 1–12. http://dx.doi.org/10.1155/2018/1361867.
Повний текст джерелаАнотація:
The connectivity of the stream network plays an important role in water-mediated transport and river environments, which are threatened by the rugged development process in China. In this study, based on graph theory, a connectivity evaluation index system was built, which includes the Edge Connectivity, Edge-Node rate, Connectivity Reliability, and Edge Weight. The new evaluation standard and calculation method of each index is presented. The river-lake system of Fenhu industrial park in Jiangsu China is simplified to an Edge-Node graph and evaluated by the index system as a case study. The results indicate that the river-lake system of the research area has low Edge Connectivity, a high Edge-Node rate, and high reliability in the current connectivity level. In addition, the Edge Weight index of several channels does not satisfy the standard of the Basic Edge Weight. To solve the connectivity problems, specific project plans include broadening the unqualified channel and building canals linked with the low-connectivity lakes. The results show that, after the planning, the connectivity of the stream network in Fenhu industrial park will increase, and the connectivity evaluation index system is useful in the study area.