Articles de revues sur le sujet « Temporal scheduler »
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Shahsavari, Shahram, Nail Akar et Babak Hossein Khalaj. « Joint Cell Muting and User Scheduling in Multicell Networks with Temporal Fairness ». Wireless Communications and Mobile Computing 2018 (2018) : 1–18. http://dx.doi.org/10.1155/2018/4846291.
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A semicentralized joint cell muting and user scheduling scheme for interference coordination in a multicell network is proposed under two different temporal fairness criteria. In the proposed scheme, at a decision instant, each base station (BS) in the multicell network employs a cell-level scheduler to nominate one user for each of its inner and outer sections and their available transmission rates to a network-level scheduler which then computes the potential overall transmission rate for each muting pattern. Subsequently, the network-level scheduler selects one pattern to unmute, out of all the available patterns. This decision is shared with all cell-level schedulers which then forward data to one of the two nominated users provided the pattern they reside in was chosen for transmission. Both user and pattern selection decisions are made on a temporal fair basis. Although some pattern sets are easily obtainable from static frequency reuse systems, we propose a general pattern set construction algorithm in this paper. As for the first fairness criterion, all cells are assigned to receive the same temporal share with the ratio between the temporal share of a cell center section and that of the cell edge section being set to a fixed desired value for all cells. The second fairness criterion is based on max-min temporal fairness for which the temporal share of the network-wide worst case user is maximized. Extensive numerical results are provided to validate the effectiveness of the proposed schemes and to study the impact of choice of the pattern set.
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Coles, Andrew, Maria Fox, Keith Halsey, Derek Long et Amanda Smith. « Managing concurrency in temporal planning using planner-scheduler interaction ». Artificial Intelligence 173, no 1 (janvier 2009) : 1–44. http://dx.doi.org/10.1016/j.artint.2008.08.003.
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Muoka, Pascal, Daniel Onwuchekwa et Roman Obermaisser. « Adaptive Scheduling for Time-Triggered Network-on-Chip-Based Multi-Core Architecture Using Genetic Algorithm ». Electronics 11, no 1 (24 décembre 2021) : 49. http://dx.doi.org/10.3390/electronics11010049.
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Adaptation in time-triggered systems can be motivated by energy efficiency, fault recovery, and changing environmental conditions. Adaptation in time-triggered systems is achieved by preserving temporal predictability through metascheduling techniques. Nevertheless, utilising existing metascheduling schemes for time-triggered network-on-chip architectures poses design time computation and run-time storage challenges for adaptation using the resulting schedules. In this work, an algorithm for path reconvergence in a multi-schedule graph, enabled by a reconvergence horizon, is presented to manage the state-space explosion problem resulting from an increase in the number of scenarios required for adaptation. A meta-scheduler invokes a genetic algorithm to solve a new scheduling problem for each adaptation scenario, resulting in a multi-schedule graph. Finally, repeated nodes of the multi-schedule graph are merged, and further exploration of paths is terminated. The proposed algorithm is evaluated using various application model sizes and different horizon configurations. Results show up to 56% reduction of schedules necessary for adaptation to 10 context events, with the reconvergence horizon set to 50 time units. Furthermore, 10 jobs with 10 slack events and a horizon of 40 ticks result in a 23% average sleep time for energy savings. Furthermore, the results demonstrate the reduction in the state-space size while showing the trade-off between the size of the reconvergence horizon and the number of nodes of the multi-schedule graph.
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Usip, Patience Usoro, Udoinyang Godwin Inyang, Daniel Ekpenyong Asuquo et Enobong Umoren. « A Formal Ontology-based Framework Towards an Intelligent Temporal Scheduler ». Advances in Science, Technology and Engineering Systems Journal 4, no 2 (2019) : 387–94. http://dx.doi.org/10.25046/aj040248.
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Liu, Ruisen, Manisha Natarajan et Matthew C. Gombolay. « Coordinating Human-Robot Teams with Dynamic and Stochastic Task Proficiencies ». ACM Transactions on Human-Robot Interaction 11, no 1 (31 mars 2022) : 1–42. http://dx.doi.org/10.1145/3477391.
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As robots become ubiquitous in the workforce, it is essential that human-robot collaboration be both intuitive and adaptive. A robot’s ability to coordinate team activities improves based on its ability to infer and reason about the dynamic (i.e., the “learning curve”) and stochastic task performance of its human counterparts. We introduce a novel resource coordination algorithm that enables robots to schedule team activities by (1) actively characterizing the task performance of their human teammates and (2) ensuring the schedule is robust to temporal constraints given this characterization. We first validate our modeling assumptions via user study. From this user study, we create a data-driven prior distribution over human task performance for our virtual and physical evaluations of human-robot teaming. Second, we show that our methods are scalable and produce high-quality schedules. Third, we conduct a between-subjects experiment (n = 90) to assess the effects on a human-robot team of a robot scheduler actively exploring the humans’ task proficiency. Our results indicate that human-robot working alliance ( ) and human performance ( ) are maximized when the robot dedicates more time to exploring the capabilities of human teammates.
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Shahsavari, Shahram, et Nail Akar. « A Two-Level Temporal Fair Scheduler for Multi-Cell Wireless Networks ». IEEE Wireless Communications Letters 4, no 3 (juin 2015) : 269–72. http://dx.doi.org/10.1109/lwc.2015.2406752.
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Hussien, Hesham, Eman Shaaban et Said Ghoniemy. « Adaptive Hierarchical Scheduling Framework for TiRTOS ». International Journal of Embedded and Real-Time Communication Systems 10, no 1 (janvier 2019) : 119–35. http://dx.doi.org/10.4018/ijertcs.2019010107.
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The complexity of embedded real-time systems has increased, and most applications have large diversity in execution times of their tasks. Therefore, most traditional scheduling techniques do not satisfy requirements of such applications. This article proposes an adaptive hierarchical scheduling framework for a set of independent concurrent applications composing of soft and hard real time tasks, that run on a single processor. It ensures temporal partitioning between independent applications with budget adaption feature, where CPU time of each application is periodically and dynamically assigned. Implemented in the kernel of TI-RTOS on a resource constrained platform, experiments show that proposed scheme provides good performance for multiple applications with dynamic tasks under overload conditions. Compared with traditional priority scheduler originally implemented in TI-RTOS and EDF scheduler, it achieves low miss ratio with minimal overhead while yielding temporal partitioning.
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Várkonyi-Kóczy, Annamária R., et Gábor Samu. « Anytime System Scheduler for Insufficient Resource Availability ». Journal of Advanced Computational Intelligence and Intelligent Informatics 8, no 5 (20 septembre 2004) : 488–94. http://dx.doi.org/10.20965/jaciii.2004.p0488.
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Anytime systems are advantageous when resource and/or data availability changes during operation and some kind of intelligent reconfiguration of the system is needed to cope with temporal data and resource access conditions. Such systems may provide an optimal tradeoff between time/resource needs and computational complexity and the quality (accuracy) of results and are designed using special models, methods, and algorithms together with applying active monitoring for being able to supervise the operation of the system on-line and making intelligent decisions based on sensory information of so-called shortage indicators. Since the monitor operates under prescribed response time requirements and the number and complexity of the executable tasks may be very high, especially in complex systems, new considerations must constantly be made to achieve optimal or acceptable performance. In software terms, this requires the application of special compilation methods dealing also with timing considerations and constraints of the underlying operating system and even with the run-time characteristics of the monitor. This must also be supported by anytime development tools and special anytime description languages. In this paper a hierarchical compilation method is introduced together with theoretical considerations about a possible anytime development tool and the basics of the anytime description meta-language ATDL are presented.
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Tekinay, Mustafa, et Cory Beard. « Reducing computation time of a wireless resource scheduler by exploiting temporal channel characteristics ». Wireless Networks 25, no 7 (10 juillet 2019) : 4259–74. http://dx.doi.org/10.1007/s11276-019-02088-2.
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Nguyen, Cuong M., et V. Chandrasekar. « Electronic Scan Strategy for Phased Array Weather Radar Using a Space–Time Characterization Model ». Journal of Atmospheric and Oceanic Technology 34, no 4 (avril 2017) : 921–38. http://dx.doi.org/10.1175/jtech-d-16-0021.1.
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AbstractThis paper presents an adaptive scan strategy concept for phased array weather radars (PAWR) with the objective of increasing the scan speed and capturing features of the storm system while maintaining the measurement accuracy. The adaptive scan strategy is developed based on the space–time variability of the storm under observation. Quickly evolving regions are scanned more often and the spatial sampling resolution is matched to the spatial scale. A model that includes the interaction between space and time is used to extract spatial and temporal scales of the medium and to define scanning regions. The temporal scale constrains the radar revisit time, while the measurement accuracy controls the radar’s dwell time. These conditions are employed in a task scheduler that works on a ray-by-ray basis and is designed to balance task priority and radar resources. The scheduler algorithm also includes an optimization procedure for minimizing radar scan time. The model and the scan strategy are demonstrated using simulation data. The results show that the proposed scan strategy can reduce the scan time significantly without compromising data quality.
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Chi, Wayne, Steve Chien et Jagriti Agrawal. « Scheduling with Complex Consumptive Resources for a Planetary Rover ». Proceedings of the International Conference on Automated Planning and Scheduling 30 (1 juin 2020) : 348–56. http://dx.doi.org/10.1609/icaps.v30i1.6680.
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Generating and scheduling activities is particularly challenging when considering both consumptive resources and complex resource interactions such as time-dependent resource usage. We present three methods of determining valid temporal placement intervals for an activity in a temporally grounded plan in the presence of such constraints. We introduce the Max Duration and Probe algorithms which are sound, but incomplete, and the Linear algorithm which is sound and complete for linear rate resource consumption. We apply these techniques to the problem of scheduling awake and asleep episodes for a planetary rover where the awake durations are affected by scheduled activities. We demonstrate how the Probe algorithm performs competitively with the Linear algorithm given an advantageous problem space and well-defined heuristics. We show that the Probe and Linear algorithms outperform the Max Duration algorithm empirically. We then present the runtime differences between the three algorithms. The Probe algorithm is currently base-lined for use in the onboard scheduler for NASA's next planetary rover, the Mars 2020 rover.
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Yigit, Yasin, Orhan Dagdeviren et Moharram Challenger. « Self-Stabilizing Capacitated Vertex Cover Algorithms for Internet-of-Things-Enabled Wireless Sensor Networks ». Sensors 22, no 10 (16 mai 2022) : 3774. http://dx.doi.org/10.3390/s22103774.
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Wireless sensor networks (WSNs) achieving environmental sensing are fundamental communication layer technologies in the Internet of Things. Battery-powered sensor nodes may face many problems, such as battery drain and software problems. Therefore, the utilization of self-stabilization, which is one of the fault-tolerance techniques, brings the network back to its legitimate state when the topology is changed due to node leaves. In this technique, a scheduler decides on which nodes could execute their rules regarding spatial and temporal properties. A useful graph theoretical structure is the vertex cover that can be utilized in various WSN applications such as routing, clustering, replica placement and link monitoring. A capacitated vertex cover is the generalized version of the problem which restricts the number of edges covered by a vertex by applying a capacity constraint to limit the covered edge count. In this paper, we propose two self-stabilizing capacitated vertex cover algorithms for WSNs. To the best of our knowledge, these algorithms are the first attempts in this manner. The first algorithm is stabilized under an unfair distributed scheduler (that is, the scheduler which does not grant all enabled nodes to make their moves but guarantees the global progress of the system) at most O(n2) step, where n is the count of nodes. The second algorithm assumes 2-hop (degree 2) knowledge about the network and runs under the unfair scheduler, which subsumes the synchronous and distributed fair scheduler and stabilizes itself after O(n) moves in O(n) step, which is acceptable for most WSN setups. We theoretically analyze the algorithms to provide proof of correctness and their step complexities. Moreover, we provide simulation setups by applying IRIS sensor node parameters and compare our algorithms with their counterparts. The gathered measurements from the simulations revealed that the proposed algorithms are faster than their competitors, use less energy and offer better vertex cover solutions.
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Vaquero, Tiago, Steve Chien, Jagriti Agrawal, Wayne Chi et Terrance Huntsberger. « Temporal Brittleness Analysis of Task Networks for Planetary Rovers ». Proceedings of the International Conference on Automated Planning and Scheduling 29 (25 mai 2021) : 564–72. http://dx.doi.org/10.1609/icaps.v29i1.3553.
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We propose a new method to analyze the temporal brittleness of task networks, which allows the detection and enumeration of activities that, with modest task execution duration variation make the execution of the task network dynamically uncontrollable. In this method, we introduce a metric for measuring an activity brittleness – defined as the degree of acceptable deviation of its nominal duration – and describe how that measurement is mapped to task network structure. Complementary to existing work on plan robustness analysis which informs how likely a task network is to succeed or not, the proposed analysis and metric go deeper to pinpoint the sources of potential brittleness due to temporal constraints and to focus either human designers and/or automated task network generators (e.g. scheduler/planners) to address sources of undesirable brittleness. We apply the approach to a set of task networks (called sol types) in development for NASA’s next planetary rover and present common patterns that are sources of brittleness. These techniques are currently under evaluation for potential use supporting operations of the Mars 2020 rover.
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Liu, Mengqi, Zhong Shao, Hao Chen, Man-Ki Yoon et Jung-Eun Kim. « Compositional virtual timelines : verifying dynamic-priority partitions with algorithmic temporal isolation ». Proceedings of the ACM on Programming Languages 6, OOPSLA2 (31 octobre 2022) : 60–88. http://dx.doi.org/10.1145/3563290.
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Real-time systems power safety-critical applications that require strong isolation among each other. Such isolation needs to be enforced at two orthogonal levels. On the micro-architectural level, this mainly involves avoiding interference through micro-architectural states, such as cache lines. On the algorithmic level, this is usually achieved by adopting real-time partitions to reserve resources for each application. Implementations of such systems are often complex and require formal verification to guarantee proper isolation. In this paper, we focus on algorithmic isolation, which is mainly related to scheduling-induced interferences. We address earliest-deadline-first (EDF) partitions to achieve compositionality and utilization, while imposing constraints on tasks' periods and enforcing budgets on these periodic partitions to ensure isolation between each other. The formal verification of such a real-time OS kernel is challenging due to the inherent complexity of the dynamic priority assignment on the partition level. We tackle this problem by adopting a dynamically constructed abstraction to lift the reasoning of a concrete scheduler into an abstract domain. Using this framework, we verify a real-time operating system kernel with budget-enforcing EDF partitions and prove that it indeed ensures isolation between partitions. All the proofs are mechanized in Coq.
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Staroletov, Sergey Mikhailovich. « A Formal Model of a Partitioned Real-Time Operating System in Promela ». Proceedings of the Institute for System Programming of the RAS 32, no 6 (2020) : 49–66. http://dx.doi.org/10.15514/ispras-2020-32(6)-4.
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Real-time partitioned operating systems meet the current avionics standard of reliable software; they are capable of responding to events from devices with an expected speed, as well as sharing processor time and memory between isolated partitions. Model-based Checking is a formal verification technique in which a software model is developed and then it is automatically checked for the compliance with formal requirements. This method allows proving the correct operation of the model on all possible input data, all possible ways of processes switching and interactions. In this article, we describe a formalized model of an open-source partitioned operating system POK. We implement the model in Promela language for SPIN tool with the purposes of formal verification using the Model Checking method. The model is designed to describe the behavior of: partition and process schedulers, system calls through a software interrupt, kernel libraries for working with synchronization primitives and processes awaiting, user code which consists of several processes in different partitions that are synchronized through a semaphore. The described approach can be used to verify the correct synchronization, the proper operation of the scheduler algorithms, and the accurate data access from different partitions by introducing the corresponding requirements in the form of formulas of the linear-time temporal logic.
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Sultana, Zeenath, Raafiya Gulmeher et Asra Sarwath. « Methods for optimizing the assignment of cloud computing resources and the scheduling of related tasks ». Indonesian Journal of Electrical Engineering and Computer Science 33, no 2 (1 février 2024) : 1092. http://dx.doi.org/10.11591/ijeecs.v33.i2.pp1092-1099.
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<div align="center"><span>Efficient scheduling algorithms are necessary in the cloud paradigm to optimize service provision to clients while minimizing time duration, energy consumption, and violations of service level agreements (SLAs). Disregarding task appropriateness in resource scheduling can have a detrimental effect on the quality of service provided by cloud providers. Moreover, the utilization of resources in an ineffective manner will necessitate a substantial expenditure of energy to execute activities, leading to prolonged processing duration that adversely affect the temporal duration. Many research projects have focused on employment scheduling problems, and the algorithms used in these studies have offered answers that were deemed nearly flawless. This study presents a chaos bird swarm algorithm (Chaos BSA) approach that use machine learning to consider task priority while allocating tasks to the cloud platform. The method calculates the priorities of task virtual machines and incorporates these values into the scheduler. The scheduler will select tasks that align with the specified priorities and are compatible with the virtual machines. The implementation of the system utilized the openstack cloud platform and the cloudsim tool. The results and comparison with the baseline approach genetic algorithm (GA), ant colony optimization (ACO), and particle swarm optimization (PSO) clearly demonstrate that our Chaos BSA outperforms them by 18% in terms of efficiency.</span></div>
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Güld, M. O., C. Thies, B. Fischer, K. Spitzer, D. Keysers, H. Ney, M. Kohnen, H. Schubert, B. B. Wein et T. M. Lehmann. « Content-based Image Retrieval in Medical Applications ». Methods of Information in Medicine 43, no 04 (2004) : 354–61. http://dx.doi.org/10.1055/s-0038-1633877.
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Summary Objectives: To develop a general structure for semantic image analysis that is suitable for content-based image retrieval in medical applications and an architecture for its efficient implementation. Methods: Stepwise content analysis of medical images results in six layers of information modeling incorporating medical expert knowledge (raw data layer, registered data layer, feature layer, scheme layer, object layer, knowledge layer). A reference database with 10,000 images categorized according to the image modality, orientation, body region, and biological system is used. By means of prototypes in each category, identification of objects and their geometrical or temporal relationships are handled in the object and the knowledge layer, respectively. A distributed system designed with only three core elements is implemented: (i) the central database holds program sources, processing scheme descriptions, images, features, and administrative information about the workstation cluster; (ii) the scheduler balances distributed computing; and (iii) the web server provides graphical user interfaces for data entry and retrieval, which can be easily adapted to a variety of applications for content-based image retrieval in medicine. Results: Leaving-one-out experiments were distributed by the scheduler and controlled via corresponding job lists offering transparency regarding the viewpoints of a distributed system and the user. The proposed architecture is suitable for content-based image retrieval in medical applications. It improves current picture archiving and communication systems that still rely on alphanumerical descriptions, which are insufficient for image retrieval of high recall and precision.
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Jian, Jie, Lide Wang, Huang Chen et Xiaobo Nie. « Scheduling Optimization of Time-Triggered Cyber-Physical Systems Based on Fuzzy-Controlled QPSO and SMT Solver ». Energies 13, no 3 (4 février 2020) : 668. http://dx.doi.org/10.3390/en13030668.
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The time-triggered communication paradigm is a cost-efficient way to meet the real-time requirements of cyber-physical systems. It is a non-deterministic polynomial NP-complete problem for multi-hop networks and non-strictly periodic traffic. A two-level scheduling approach is proposed to simplify the complexity during optimization. In the first level, a fuzzy-controlled quantum-behaved particle swarm optimization (FQPSO) algorithm is proposed to optimize the scheduling performance by assigning time-triggered frame instances to the basic periods of each link. In order to prevent population from high aggregation, a random mutation mechanism is used to disturb particles at the aggregation point and enhance the diversity at later stages. Fuzzy logic is introduced and well designed to realize a dynamic adaptive adjustment of the contraction–expansion coefficient and mutation rate in FQPSO. In the second level, we use an improved Satisfiability Modulo Theories (SMT) scheduling algorithm to solve the collision-free and temporal constraints. A schedulability ranking method is proposed to accelerate the computation of the SMT-based incremental scheduler. Our approach can co-optimize the jitter and load balance of communication for an off-line schedule. The experiments show that the proposed approach can improve the performance of the scheduling table, reduce the optimization time, and reserve space for incremental messages.
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Lee, Joon Young, Vivaswat Ojha et James C. Boerkoel Jr. « Measuring and Optimizing Durability against Scheduling Disturbances ». Proceedings of the International Conference on Automated Planning and Scheduling 29 (25 mai 2021) : 264–68. http://dx.doi.org/10.1609/icaps.v29i1.3486.
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Flexibility is a useful and common metric for measuring the amount of slack in a Simple Temporal Network (STN) solution space. We extend this concept to specific schedules within an STN’s solution space, developing a related notion of durability that captures an individual schedule’s ability to withstand disturbances and still remain valid. We identify practical sources of scheduling disturbances that motivate the need for durable schedules, and create a geometricallyinspired empirical model that enables testing a given schedule’s ability to withstand these disturbances. We develop a number of durability metrics and use these to characterize and compute specific schedules that we expect to have high durability. Using our model of disturbances, we show that our durability metrics strongly predict a schedule’s resilience to practical scheduling disturbances. We also demonstrate that the schedules we identify as having high durability are up to three times more resilient to disturbances than an arbitrarily chosen schedule is.
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Doyon, Frédérik, Stephen Yamasaki et Robin Duchesneau. « The use of the natural range of variability for identifying biodiversity values at risk when implementing a forest management strategy ». Forestry Chronicle 84, no 3 (1 juin 2008) : 316–29. http://dx.doi.org/10.5558/tfc84316-3.
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The Natural Range of Variability is a concept used under the ecosystem management paradigm that means understanding the disturbance-driven spatial and temporal variability of the ecological systems and mimicking them in management strategies. With this project, we developed a framework that permitted addressing biodiversity issues under the lens of the Natural Range of Variability (NRV) for a managed public forest in central-west Alberta. To do so, we brought together a spatial harvest scheduler, a fire and succession landscape simulator, and a toolbox of biodiversity indicator models. Indicator models, that encompass landscape configuration, ecosystem diversity, stand internal habitat features and speciesspecific habitat supply models, were applied on the outputs of the landscape dynamics simulator to define the NRV. The risk of losing biodiversity values in applying the forest management strategy was addressed by comparing indicators outputs over the simulation horizon with their respective NRV. Results demonstrate that no forest-age-related indicator evaluated on the harvest scheduler output shows an important deviation from the NRV. However, in regards to forest cover types there is obviously a loss in ecosystem diversity, as a direct effect of the stand composition control of the silvicultural strategies. We found that patch size distribution is generally compliant with the NRV, although we observed more large patches and better connectivity for old growth patches under fire-driven landscapes. We also found that downed woody debris volume and many understory vegetation (ground lichen, herb and shrub) covers were at risk. Over the seventeen wildlife species, we detected nine species that could be jeopardized by important loss of habitats. Back-tracking bottleneck forest conditions that put these biodiversity values at risk has allowed development of recommendations with regards to landscape design and adapted practices. Key words: BAP toolbox, fire-driven landscape, natural disturbance regime, ecosystem diversity, landscape configuration, wildlife habitat models, risk analysis
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Nir, Ronen, et Erez Karpas. « Automated Verification of Social Laws for Continuous Time Multi-Robot Systems ». Proceedings of the AAAI Conference on Artificial Intelligence 33 (17 juillet 2019) : 7683–90. http://dx.doi.org/10.1609/aaai.v33i01.33017683.
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Designing multi-agent systems, where several agents work in a shared environment, requires coordinating between the agents so they do not interfere with each other. One of the canonical approaches to coordinating agents is enacting a social law, which applies restrictions on agents’ available actions. A good social law prevents the agents from interfering with each other, while still allowing all of them to achieve their goals. Recent work took the first step towards reasoning about social laws using automated planning and showed how to verify if a given social law is robust, that is, allows all agents to achieve their goals regardless of what the other agents do. This work relied on a classical planning formalism, which assumed actions are instantaneous and some external scheduler chooses which agent acts next. However, this work is not directly applicable to multi-robot systems, because in the real world actions take time and the agents can act concurrently. In this paper, we show how the robustness of a social law in a continuous time setting can be verified through compilation to temporal planning. We demonstrate our work both theoretically and on real robots.
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Qiao, Xiaoyu, Weiliang Xie et Fengyi Yang. « Cooperative Sequential Sensing of Radio Transmissions in 5G with Improved Cost-Delay Tradeoff ». International Journal of Distributed Sensor Networks 2015 (2015) : 1–12. http://dx.doi.org/10.1155/2015/456074.
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The fifth-generation (5G) wireless networks are generally anticipated to be heterogeneous, consisting of macro cells, wireless local area networks, device-to-device networks, ad hoc networks, and so forth. The spectrum occupancy varies on spatial and temporal basis. So sensing the variation of spectrum occupancy and informing the resource scheduler can optimize the utilization efficiency of spectrum. Especially for deployment of cognitive radio in 5G, spectrum sensing is regarded as a key technique. In this work, we study the cooperative sensing in 5G heterogeneous wireless networks with a centralized control module. By formulating this cooperative sensing problem as a sequential binary hypothesis test problem, the number of unnecessary data samples and the associated cost is substantially reduced, with guaranteed detection precision. We develop a cooperative sequential detection algorithm, in which multiple geographically diverse sensors are sequentially set up to measure and transmit measurement results on demand. Furthermore, we consider different sensor sampling schemes to address the cost-delay tradeoff problems and then propose a conditional mean activation and sampling algorithm, in which the number of required samples is predicted based on the quality of the collected samples. The performances of different sensor sampling schemes are demonstrated under different sensing environments.
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Cho, Se Yeon, Raimarius Delgado et Byoung Wook Choi. « Feasibility Study for a Python-Based Embedded Real-Time Control System ». Electronics 12, no 6 (16 mars 2023) : 1426. http://dx.doi.org/10.3390/electronics12061426.
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Because of its simplicity and the support of numerous useful libraries, Python has become one of the most popular programming languages for application development, even in embedded systems. However, in existing control systems where specific tasks must meet specific temporal deadlines and support schedulability with proper priority assignments, the Python interpreter may not satisfy real-time requirements, owing to features such as the global interpreter lock and garbage collector. This paper addresses these constraints with an approach that executes periodic real-time tasks under the fixed-priority preemptible scheduler of RT-Preempt. First, we implemented a Python real-time module that allows users to create and execute periodic tasks with fixed priorities based on Python. Then, we conducted experiments on an open embedded system, in this case, a Raspberry Pi 4. We evaluated the real-time performance, focusing on test metrics for control systems, such as task periodicity, responsiveness, and interrupt response. The results were then compared to those of conventional real-time tasks developed using the C language to validate the feasibility of the proposed method. Finally, we performed experimental validation by tracking the position of EtherCAT servo motors to demonstrate the feasibility of a Python-based real-time control system in a practical application.
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Subramaniam, Shrinidhi, et Elizabeth G. E. Kyonka. « Selective attention in pigeon temporal discrimination ». Quarterly Journal of Experimental Psychology 72, no 2 (1 janvier 2018) : 298–310. http://dx.doi.org/10.1080/17470218.2017.1360921.
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Cues can vary in how informative they are about when specific outcomes, such as food availability, will occur. This study was an experimental investigation of the functional relation between cue informativeness and temporal discrimination in a peak-interval (PI) procedure. Each session consisted of fixed-interval (FI) 2- and 4-s schedules of food and occasional, 12-s PI trials during which pecks had no programmed consequences. Across conditions, the phi (ϕ) correlation between key light color and FI schedule value was manipulated. Red and green key lights signaled the onset of either or both FI schedules. Different colors were either predictive (ϕ = 1), moderately predictive (ϕ = 0.2-0.8) or not predictive (ϕ = 0) of a specific FI schedule. This study tested the hypothesis that temporal discrimination is a function of the momentary conditional probability of food; that is, pigeons peck the most at either 2 s or 4 s when ϕ = 1 and peck at both intervals when ϕ < 1. Response distributions were bimodal Gaussian curves; distributions from red- and green-key PI trials converged when ϕ ≤ 0.6. Peak times estimated by summed Gaussian functions, averaged across conditions and pigeons, were 1.85 and 3.87 s; however, pigeons did not always maximize the momentary probability of food. When key light color was highly correlated with FI schedules (ϕ ≥ 0.6), estimates of peak times indicated that temporal discrimination accuracy was reduced at the unlikely interval, but not the likely interval. The mechanism of this reduced temporal discrimination accuracy could be interpreted as an attentional process.
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Reid, Alliston K., Patricia Piñones Vazquez et Javier Alatorre Rico. « Schedule induction and the temporal distributions of adjunctive behavior on periodic water schedules ». Animal Learning & ; Behavior 13, no 3 (septembre 1985) : 321–26. http://dx.doi.org/10.3758/bf03200027.
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Boerkoel Jr., James, et Edmund Durfee. « Decoupling the Multiagent Disjunctive Temporal Problem ». Proceedings of the AAAI Conference on Artificial Intelligence 27, no 1 (30 juin 2013) : 123–29. http://dx.doi.org/10.1609/aaai.v27i1.8583.
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The Multiagent Disjunctive Temporal Problem (MaDTP) is a general constraint-based formulation for scheduling problems that involve interdependent agents. Decoupling agents' interdependent scheduling problems, so that each agent can manage its schedule independently, requires agents to adopt additional local constraints that effectively subsume their interdependencies. In this paper, we present the first algorithm for decoupling MaDTPs. Our distributed algorithm is provably sound and complete. Our experiments show that the relative efficiency of using temporal decoupling to find solution spaces for MaDTPs, compared to algorithms that find complete solution spaces, improves with the interconnectedness between agents schedules, leading to orders of magnitude relative speeedup. However, decoupling by its nature restricts agents' scheduling flexibility; we define novel flexibility metrics for MaDTPs, and show empirically how the flexibility sacrificed depends on the degree of coupling between agents' schedules.
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Jamnick, Mark S., et Karl R. Walters. « Spatial and temporal allocation of stratum-based harvest schedules ». Canadian Journal of Forest Research 23, no 3 (1 mars 1993) : 402–13. http://dx.doi.org/10.1139/x93-058.
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Stratum-based timber harvest schedules must be disaggregated into operational plans prior to implementation. In most cases this is an expensive and time-consuming manual task that does not ensure consistency between the long-term harvest schedule and short-term operational activities. This paper presents the results of applying the CRYSTAL algorithm, which automates the disaggregation and allocation of a stratum-based harvest schedule into harvest blocks, to a small forest in New Brunswick. The results indicate that it is possible to use a set of allocation guidelines to quickly delineate harvest blocks in a consistent, reproducible manner. We also discuss how the algorithm is used in conjunction with a Monte Carlo integer programming model to estimate the potential losses in timber harvest volumes attributable to deviations from the stratum-based schedule and the addition of adjacency constraints.
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Gao, Michael, Lindsay Popowski et Jim Boerkoel. « Dynamic Control of Probabilistic Simple Temporal Networks ». Proceedings of the AAAI Conference on Artificial Intelligence 34, no 06 (3 avril 2020) : 9851–58. http://dx.doi.org/10.1609/aaai.v34i06.6538.
Texte intégralRésumé :
The controllability of a temporal network is defined as an agent's ability to navigate around the uncertainty in its schedule and is well-studied for certain networks of temporal constraints. However, many interesting real-world problems can be better represented as Probabilistic Simple Temporal Networks (PSTNs) in which the uncertain durations are represented using potentially-unbounded probability density functions. This can make it inherently impossible to control for all eventualities. In this paper, we propose two new dynamic controllability algorithms that attempt to maximize the likelihood of successfully executing a schedule within a PSTN. The first approach, which we call Min-Loss DC, finds a dynamic scheduling strategy that minimizes loss of control by using a conflict-directed search to decide where to sacrifice the control in a way that optimizes overall success. The second approach, which we call Max-Gain DC, works in the other direction: it finds a dynamically controllable schedule and then attempts to progressively strengthen it by capturing additional uncertainty. Our approaches are the first known that work by finding maximally dynamically controllable schedules. We empirically compare our approaches against two existing PSTN offline dispatch approaches and one online approach and show that our Min-Loss DC algorithm outperforms the others in terms of maximizing execution success while maintaining competitive runtimes.
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Murray, Andrew, Ashwin Arulselvan, Michael Cashmore, Marc Roper et Jeremy Frank. « A Column Generation Approach to Correlated Simple Temporal Networks ». Proceedings of the International Conference on Automated Planning and Scheduling 33, no 1 (1 juillet 2023) : 295–303. http://dx.doi.org/10.1609/icaps.v33i1.27207.
Texte intégralRésumé :
Probabilistic Simple Temporal Networks (PSTN) represent scheduling problems under temporal uncertainty. Strong controllability (SC) of PSTNs involves finding a schedule to a PSTN that maximises the probability that all constraints are satisfied (robustness). Previous approaches to this problem assume independence of probabilistic durations, and approximate the risk by bounding it above using Boole’s inequality. This gives no guarantee of finding the schedule optimising robustness, and fails to consider correlations between probabilistic durations that frequently arise in practical applications. In this paper, we formally define the Correlated Simple Temporal Network (Corr-STN) which generalises the PSTN by removing the restriction of independence. We show that the problem of Corr-STN SC is convex for a large class of multivariate (log-concave) distributions. We then introduce an algorithm capable of finding optimal SC schedules to Corr-STNs, using the column generation method. Finally, we validate our approach on a number of Corr-STNs and find that our method offers more robust solutions when compared with prior approaches.
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Morgan, Malia, Julianna Schalkwyk, Huaxiaoyue Wang, Hannah Davalos, Ryan Martinez, Vibha Rohilla et James Boerkoel. « Simple Temporal Networks for Improvisational Teamwork ». Proceedings of the International Conference on Automated Planning and Scheduling 32 (13 juin 2022) : 261–69. http://dx.doi.org/10.1609/icaps.v32i1.19809.
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When communication between teammates is limited to observations of each other's actions, agents may need to improvise to stay coordinated. Unfortunately, current methods inadequately capture the uncertainty introduced by a lack of direct communication. This paper augments existing frameworks to introduce Simple Temporal Networks for Improvisational Teamwork (STN-IT)—a formulation that captures both the temporal dependencies and uncertainties between agents who need to coordinate but lack reliable communication. We define the notion of strong controllability for STN-ITs, which establishes a static scheduling strategy for controllable agents that produces a consistent team schedule, as long as non-communicative teammates act within known problem constraints. We provide both an exact and approximate approach for finding strongly controllable schedules, empirically demonstrate the trade-offs between these approaches on benchmarks of STN-ITs, and show analytically that the exact method is correct.
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Rajalingham, Rishi, Richard Greg Stacey, Georgios Tsoulfas et Sam Musallam. « Modulation of neural activity by reward in medial intraparietal cortex is sensitive to temporal sequence of reward ». Journal of Neurophysiology 112, no 7 (1 octobre 2014) : 1775–89. http://dx.doi.org/10.1152/jn.00533.2012.
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To restore movements to paralyzed patients, neural prosthetic systems must accurately decode patients' intentions from neural signals. Despite significant advancements, current systems are unable to restore complex movements. Decoding reward-related signals from the medial intraparietal area (MIP) could enhance prosthetic performance. However, the dynamics of reward sensitivity in MIP is not known. Furthermore, reward-related modulation in premotor areas has been attributed to behavioral confounds. Here we investigated the stability of reward encoding in MIP by assessing the effect of reward history on reward sensitivity. We recorded from neurons in MIP while monkeys performed a delayed-reach task under two reward schedules. In the variable schedule, an equal number of small- and large-rewards trials were randomly interleaved. In the constant schedule, one reward size was delivered for a block of trials. The memory period firing rate of most neurons in response to identical rewards varied according to schedule. Using systems identification tools, we attributed the schedule sensitivity to the dependence of neural activity on the history of reward. We did not find schedule-dependent behavioral changes, suggesting that reward modulates neural activity in MIP. Neural discrimination between rewards was less in the variable than in the constant schedule, degrading our ability to decode reach target and reward simultaneously. The effect of schedule was mitigated by adding Haar wavelet coefficients to the decoding model. This raises the possibility of multiple encoding schemes at different timescales and reinforces the potential utility of reward information for prosthetic performance.
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Boakes, Robert A., Angela E. Patterson, Michael D. Kendig et Justin A. Harris. « Temporal distributions of schedule-induced licks, magazine entries, and lever presses on fixed- and variable-time schedules. » Journal of Experimental Psychology : Animal Learning and Cognition 41, no 1 (2015) : 52–68. http://dx.doi.org/10.1037/xan0000046.
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Gutiérrez-Ferre, Valeria E., et Ricardo Pellón. « Wheel running induced by intermittent food schedules ». Psicológica Journal 40, no 2 (1 juillet 2019) : 46–61. http://dx.doi.org/10.2478/psicolj-2019-0004.
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AbstractSixteen naïve male Wistar rats were exposed to intermittent food delivery to measure the development of schedule-induced wheel running, using fixed time (FT) 30, 60, 120, 240 and 480 s schedules, counterbalanced across animals according to a Latin square design (except under the FT 480 s, which was always presented last to complete the data set). Rats were also exposed to a massed-food control condition. Wheel running was induced in the range of 30-240 s with a gradation as a function of inter-food interval (IFI) length. The temporal distribution of wheel turns was generally presented in the form of an inverted U-shaped as IFIs progressed, showing maximum responding during the first portion of the interval. The introduction of massed-food resulted in an immediate reduction in wheel running. These results support the notion that wheel running can be schedule-induced and categorized into the so-called adjunctive behaviors. These data indicate that IFI length affects the development of schedule-induced wheel running and that the rate of wheel running is maintained by intermittent reinforcement, which are common characteristics of schedule-induced behaviors. Likewise, this idea is supported by the occurrence of a similar temporal pattern to that found with other adjunctive behaviors, such as schedule-induced polydipsia, with its maximum manifestation occurring between the beginning and middle of IFIs.
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Yeraguntla, Aswani, et Chandra R. Bhat. « Classification Taxonomy and Empirical Analysis of Work Arrangements ». Transportation Research Record : Journal of the Transportation Research Board 1926, no 1 (janvier 2005) : 233–41. http://dx.doi.org/10.1177/0361198105192600127.
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The work-related characteristics of an individual act as pegs around which other nonwork activities are scheduled on a day-to-day basis. In this paper, four dimensions of the medium- to long-range work arrangements that are important to day-to-day temporal and spatial characteristics of work patterns (and hence to day-to-day activity–travel schedules) are identified. The four dimensions are full-time versus part-time employment, teleworking or not, inflexible or flexible work schedules, and regular or alternate shifts. This paper develops a comprehensive taxonomy of work arrangements in each of these four dimensions and empirically analyses the factors affecting the work arrangement decisions along three of these dimensions.
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Liu, Zheng, et Barry J. Richmond. « Response Differences in Monkey TE and Perirhinal Cortex : Stimulus Association Related to Reward Schedules ». Journal of Neurophysiology 83, no 3 (1 mars 2000) : 1677–92. http://dx.doi.org/10.1152/jn.2000.83.3.1677.
Texte intégralRésumé :
Anatomic and behavioral evidence shows that TE and perirhinal cortices are two directly connected but distinct inferior temporal areas. Despite this distinctness, physiological properties of neurons in these two areas generally have been similar with neurons in both areas showing selectivity for complex visual patterns and showing response modulations related to behavioral context in the sequential delayed match-to-sample (DMS) trials, attention, and stimulus familiarity. Here we identify physiological differences in the neuronal activity of these two areas. We recorded single neurons from area TE and perirhinal cortex while the monkeys performed a simple behavioral task using randomly interleaved visually cued reward schedules of one, two, or three DMS trials. The monkeys used the cue's relation to the reward schedule (indicated by the brightness) to adjust their behavioral performance. They performed most quickly and most accurately in trials in which reward was immediately forthcoming and progressively less well as more intermediate trials remained. Thus the monkeys appeared more motivated as they progressed through the trial schedule. Neurons in both TE and perirhinal cortex responded to both the visual cues related to the reward schedules and the stimulus patterns used in the DMS trials. As expected, neurons in both areas showed response selectivity to the DMS patterns, and significant, but small, modulations related to the behavioral context in the DMS trial. However, TE and perirhinal neurons showed strikingly different response properties. The latency distribution of perirhinal responses was centered 66 ms later than the distribution of TE responses, a larger difference than the 10–15 ms usually found in sequentially connected visual cortical areas. In TE, cue-related responses were related to the cue's brightness. In perirhinal cortex, cue-related responses were related to the trial schedules independently of the cue's brightness. For example, some perirhinal neurons responded in the first trial of any reward schedule including the one trial schedule, whereas other neurons failed to respond in the first trial but respond in the last trial of any schedule. The majority of perirhinal neurons had more complicated relations to the schedule. The cue-related activity of TE neurons is interpreted most parsimoniously as a response to the stimulus brightness, whereas the cue-related activity of perirhinal neurons is interpreted most parsimoniously as carrying associative information about the animal's progress through the reward schedule. Perirhinal cortex may be part of a system gauging the relation between work schedules and rewards.
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Savage, David W., Douglas G. Woolford, Bruce Weaver et David Wood. « Developing emergency department physician shift schedules optimized to meet patient demand ». CJEM 17, no 1 (janvier 2015) : 3–12. http://dx.doi.org/10.2310/8000.2013.131224.
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AbstractObjectives: 1) To assess temporal patterns in historical patient arrival rates in an emergency department (ED) to determine the appropriate number of shift schedules in an acute care area and a fast-track clinic and 2) to determine whether physician scheduling can be improved by aligning physician productivity with patient arrivals using an optimization planning model.Methods: Historical data were statistically analyzed to determine whether the number of patients arriving at the ED varied by weekday, weekend, or holiday weekend. Poisson-based generalized additive models were used to develop models of patient arrival rate throughout the day. A mathematical programming model was used to produce an optimal ED shift schedule for the estimated patient arrival rates. We compared the current physician schedule to three other scheduling scenarios: 1) a revised schedule produced by the planning model, 2) the revised schedule with an additional acute care physician, and 3) the revised schedule with an additional fast-track clinic physician.Results: Statistical modelling found that patient arrival rates were different for acute care versus fast-track clinics; the patterns in arrivals followed essentially the same daily pattern in the acute care area; and arrival patterns differed on weekdays versus weekends in the fast-track clinic. The planning model reduced the unmet patient demand (i.e., the average number of patients arriving at the ED beyond the average physician productivity) by 19%, 39%, and 69% for the three scenarios examined.Conclusions: The planning model improved the shift schedules by aligning physician productivity with patient arrivals at the ED.
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de Zilva, Daniel, et Chris J. Mitchell. « Effects of Exposure on Discrimination of Similar Stimuli and on Memory for Their Unique and Common Features ». Quarterly Journal of Experimental Psychology 65, no 6 (juin 2012) : 1123–38. http://dx.doi.org/10.1080/17470218.2011.644304.
Texte intégralRésumé :
Human participants received exposure to similar visual stimuli (AW and BW) that shared a common feature (W). Experiment 1 demonstrated that subsequent discrimination between AW and BW was more accurate when the two stimuli were preexposed on an intermixed schedule (AW, BW, AW, BW…) than when they were preexposed on a blocked schedule (AW, AW…BW, BW…): the intermixed–blocked effect. Furthermore, memory for the unique features of the stimuli (A and B) was better when the stimuli were preexposed on an intermixed schedule than when they were preexposed on a blocked schedule. Conversely, memory for the common features of the stimuli (W) was better when the stimuli were preexposed on a blocked schedule than when they were preexposed on an intermixed schedule. Experiment 2 again demonstrated the intermixed–blocked effect, but participants were preexposed to the stimuli in such a way that the temporal spacing between exposures to the unique features was equated between schedules. Memory for the unique and common features was similar to that found in Experiment 1. These findings support the proposal that perceptual learning depends on a mechanism that enhances memory for the unique features and reduces memory for common features.
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António Ferreira Rodrigues Nogueira dos Santos, Marco, et Henrik Kurt Olof Eriksson. « Insights into physician scheduling : a case study of public hospital departments in Sweden ». International Journal of Health Care Quality Assurance 27, no 2 (3 mars 2014) : 76–90. http://dx.doi.org/10.1108/ijhcqa-02-2012-0018.
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Purpose – The purpose of this paper is to describe current physician scheduling and concomitant opportunities for improvement in public hospital departments in Sweden. Design/methodology/approach – A total of 13 departments spread geographically across Sweden covering seven different specialties participated in the study. Data were collected through interviews with individuals involved in creating physician schedules. All departments investigated provided copies of the documents necessary for physician scheduling. Findings – Physician scheduling required the temporal coordination of patients, physicians, non-physician staff, rooms and equipment. A six-step process for creating physician schedules could be distinguished: capacity and demand overview, demand goal and schedule setting, vacation and leave requests, schedule creation, schedule revision, and schedule execution. Several opportunities for improvement could be outlined; e.g. overreliance on memory, lacking coordination of resources, and redundant data entering. Research limitations/implications – The paucity of previous studies on physician scheduling lends an exploratory character to this study and calls for a more thorough evaluation of the feasibility and effects of the approaches proposed. The study excluded the scheduling of non-physician staff. Practical implications – To improve physician scheduling and enable timeliness, three approaches are proposed: reinforcing centralisation, creating learning opportunities, and improving integration. Originality/value – This paper is among the few to investigate physician scheduling, which is essential for delivering high quality care, particularly concerning timeliness. Several opportunities for improvement identified in this study are not exclusive to physician scheduling but are pervasive in healthcare processes in general.
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Zeiler, Michael D., et David G. Powell. « TEMPORAL CONTROL IN FIXED-INTERVAL SCHEDULES ». Journal of the Experimental Analysis of Behavior 61, no 1 (janvier 1994) : 1–9. http://dx.doi.org/10.1901/jeab.1994.61-1.
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Westfall, Una E. « How Enteral Feeding Options Influence Corticosterone Patterns in Rats ». Biological Research For Nursing 1, no 3 (janvier 2000) : 233–44. http://dx.doi.org/10.1177/109980040000100308.
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Even with all the nutritional research conducted to date, it is not clear which enteral nutrition delivery and composition options are most physiologically sound. Glucocorticoid temporal patterns are reported to be shifted or disrupted with restricted feeding schedules, but because of intermittent sampling, temporal patterns have not been completely depicted. The purpose of this study was to characterize corticosterone temporal patterns while systematically varying selected enteral feeding options in a well-established nutritional animal model. A 2 • 2 • 2 • 2 randomized block experimental design was used in which enteral feeding schedules, delivery methods, kilocalorie levels (kcal), and fiber contents were systematically varied in rats (n = 80), and plasma corticosterone was measured by125 I radioimmunoassay. Blood samples were drawn hourly over 24 h. With cosinor analysis, 24-h and 12-h corticosterone rhythmic components were tested in each feeding group. Five of 16 feeding groups had a significant (p £ 0.05) 24-h rhythmic component, and 3 more showed a trend (p> 0.05< 0.10); 7 of these groups were on 24-h feeding schedules. When rhythmic components were detectable, groups receiving high-fiber formula displayed more uniform rhythm characteristics than did no-fiber groups. Only 1 group had a significant 12-h rhythmic component, and 1 showed a trend. Both were on 12-h, high-fiber restricted kcal feedings. In this small animal sample, no one enteral feeding option guaranteed a 24-h corticosterone pattern. The option coming closest was formula delivered on a 24-h schedule. This temporal pattern is one aspect to consider in enteral nutrition. The underlying mechanisms have yet to be elucidated.
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Boerkoel Jr., James, et Edmund Durfee. « A Distributed Approach to Summarizing Spaces of Multiagent Schedules ». Proceedings of the AAAI Conference on Artificial Intelligence 26, no 1 (20 septembre 2021) : 1742–48. http://dx.doi.org/10.1609/aaai.v26i1.8368.
Texte intégralRésumé :
We introduce the Multiagent Disjunctive Temporal Problem (MaDTP), a new distributed formulation of the widely-adopted Disjunctive Temporal Problem (DTP) representation. An agent that generates a summary of all viable schedules, rather than a single schedule, can be more useful in dynamic environments. We show how a (Ma)DTP with the properties of minimality and decomposability provides a particularly efficacious solution space summary.However, in the multiagent case, these properties sacrifice an agent's strategic interests while incurring significant computational overhead. We introduce a new property called local decomposability that exploits loose-coupling between agents' problems, protects strategic interests, and supports typical queries. We provide and evaluate a new distributed algorithm that summarizes agents' solution spaces in significantly less time and space by using local, rather than full, decomposability.
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Cui, Jing, Peng Yu, Cheng Fang, Patrik Haslum et Brian Williams. « Optimising Bounds in Simple Temporal Networks with Uncertainty under Dynamic Controllability Constraints ». Proceedings of the International Conference on Automated Planning and Scheduling 25 (8 avril 2015) : 52–60. http://dx.doi.org/10.1609/icaps.v25i1.13723.
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Dynamically controllable simple temporal networks with uncertainty (STNU) are widely used to represent temporal plans or schedules with uncertainty and execution flexibility. While the problem of testing an STNU for dynamic controllability is well studied, many use cases — for example, problem relaxation or schedule robustness analysis — require optimising a function over STNU time bounds subject to the constraint that the network is dynamically controllable. We present a disjunctive linear constraint model of dynamic controllability, show how it can be used to formulate a range of applications, and compare a mixed-integer, a non-linear programming, and a conflict-directed search solver on the resulting optimisation problems. Our model also provides the first solution to the problem of optimisation over a probabilistic STN subject to dynamic controllability and chance constraints.
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Fang, Cheng, Andrew J. Wang et Brian C. Williams. « Chance-constrained Static Schedules for Temporally Probabilistic Plans ». Journal of Artificial Intelligence Research 75 (7 décembre 2022) : 1323–72. http://dx.doi.org/10.1613/jair.1.13636.
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Time management under uncertainty is essential to large scale projects. From space exploration to industrial production, there is a need to schedule and perform activities. given complex specifications on timing. In order to generate schedules that are robust to uncertainty in the duration of activities, prior work has focused on a problem framing that uses an interval-bounded uncertainty representation. However, such approaches are unable to take advantage of known probability distributions over duration. In this paper we concentrate on a probabilistic formulation of temporal problems with uncertain duration, called the probabilistic simple temporal problem. As distributions often have an unbounded range of outcomes, we consider chance-constrained solutions, with guarantees on the probability of meeting temporal constraints. By considering distributions over uncertain duration, we are able to use risk as a resource, reason over the relative likelihood of outcomes, and derive higher utility solutions. We first demonstrate our approach by encoding the problem as a convex program. We then develop a more efficient hybrid algorithm whose parent solver generates risk allocations and whose child solver generates schedules for a particular risk allocation. The child is made efficient by leveraging existing interval-bounded scheduling algorithms, while the parent is made efficient by extracting conflicts over risk allocations. We perform numerical experiments to show the advantages of reasoning over probabilistic uncertainty, by comparing the utility of schedules generated with risk allocation against those generated from reasoning over bounded uncertainty. We also empirically show that solution time is greatly reduced by incorporating conflict-directed risk allocation.
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Fernando, Tim. « Schedules in a Temporal Interpretation of Modals ». Journal of Semantics 22, no 2 (1 mai 2005) : 211–29. http://dx.doi.org/10.1093/jos/ffh023.
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Flores, Carlos, et Emilio Ribes-Iñesta. « Varying Temporal Placement of a Stimulus Correlated with Non-Reinforcement in a Temporally Defined Schedule ». Psychological Record 66, no 1 (10 novembre 2015) : 75–82. http://dx.doi.org/10.1007/s40732-015-0153-0.
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Vandiver, Trish, et Kenneth J. Sher. « Temporal stability of the Diagnostic Interview Schedule. » Psychological Assessment : A Journal of Consulting and Clinical Psychology 3, no 2 (1991) : 277–81. http://dx.doi.org/10.1037/1040-3590.3.2.277.
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Knight, Kathryn. « Bull ants’ eyes don't lock temporal schedule ». Journal of Experimental Biology 219, no 16 (15 août 2016) : 2411.2–2412. http://dx.doi.org/10.1242/jeb.146886.
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Irak, Doruk Uysal, et Janet Mantler. « The role of temporal flexibility on person–environment fit and job satisfaction ». Journal of Management & ; Organization 24, no 6 (2 octobre 2017) : 829–45. http://dx.doi.org/10.1017/jmo.2017.50.
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AbstractThe present study investigated the role of temporal flexibility on three conceptualizations of person–environment fit and job satisfaction. Data were collected from 320 full-time employees in Canada and America. Using structural equation modeling, it was found that temporal flexibility was directly related to increased job satisfaction and indirectly related to job satisfaction through supplementary fit, demands–abilities fit, and needs–supplies fit. Moreover, supplementary fit and demands–abilities fit were influential on perceptions of needs–supplies fit, although we acknowledge that additional research is required to further explore our novel findings of the relative relationships between the three conceptualizations of person–environment fit. The present research supports the idea that giving employees greater control over their schedule increases their autonomy, thus helping to satisfy a core psychological need. Organizations that provide employees with the opportunity to choose their own schedules may be more likely to retain satisfied and committed people who believe they fit well with their employer.
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Kim, Taeseok, Hyokyung Bahn et Youjip Won. « A Pruning-Based Disk Scheduling Algorithm for Heterogeneous I/O Workloads ». Scientific World Journal 2014 (2014) : 1–17. http://dx.doi.org/10.1155/2014/940850.
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In heterogeneous I/O workload environments, disk scheduling algorithms should support different QoS (Quality-of-Service) for each I/O request. For example, the algorithm should meet the deadlines of real-time requests and at the same time provide reasonable response time for best-effort requests. This paper presents a novel disk scheduling algorithm called G-SCAN (Grouping-SCAN) for handling heterogeneous I/O workloads. To find a schedule that satisfies the deadline constraints and seek time minimization simultaneously, G-SCAN maintains a series of candidate schedules and expands the schedules whenever a new request arrives. Maintaining these candidate schedules requires excessive spatial and temporal overhead, but G-SCAN reduces the overhead to a manageable level via pruning the state space using two heuristics. One is grouping that clusters adjacent best-effort requests into a single scheduling unit and the other is the branch-and-bound strategy that cuts off inefficient or impractical schedules. Experiments with various synthetic and real-world I/O workloads show that G-SCAN outperforms existing disk scheduling algorithms significantly in terms of the average response time, throughput, and QoS-guarantees for heterogeneous I/O workloads. We also show that the overhead of G-SCAN is reasonable for on-line execution.
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Obermaisser, Roman, Hamidreza Ahmadian, Adele Maleki, Yosab Bebawy, Alina Lenz et Babak Sorkhpour. « Adaptive Time-Triggered Multi-Core Architecture ». Designs 3, no 1 (22 janvier 2019) : 7. http://dx.doi.org/10.3390/designs3010007.
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The static resource allocation in time-triggered systems offers significant benefits for the safety arguments of dependable systems. However, adaptation is a key factor for energy efficiency and fault recovery in Cyber-Physical System (CPS). This paper introduces the Adaptive Time-Triggered Multi-Core Architecture (ATMA), which supports adaptation using multi-schedule graphs while preserving the key properties of time-triggered systems including implicit synchronization, temporal predictability and avoidance of resource conflicts. ATMA is an overall architecture for safety-critical CPS based on a network-on-a-chip with building blocks for context agreement and adaptation. Context information is established in a globally consistent manner, providing the foundation for the temporally aligned switching of schedules in the network interfaces. A meta-scheduling algorithm computes schedule graphs and avoids state explosion with reconvergence horizons for events. For each tile, the relevant part of the schedule graph is efficiently stored using difference encodings and interpreted by the adaptation logic. The architecture was evaluated using an FPGA-based implementation and example scenarios employing adaptation for improved energy efficiency. The evaluation demonstrated the benefits of adaptation while showing the overhead and the trade-off between the degree of adaptation and the memory consumption for multi-schedule graphs.