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Euromicro Conference on Real-Time Systems

作者： Mitra Nasri Gerhard Fohler Chair of Real-time Systems Technische Universität Kaiserslautern Germany

ISBN: (纸本)9781509028122

In many real-time systems, preemption is either impossible or prohibitively expensive. The problem of scheduling non-preemptive periodic tasks with known release offsets is known to be NP-Hard. In this paper, we investigate the existing non-preemptive scheduling algorithms in both categories of work-conserving and non-work-conserving algorithms, where in the former, the processing resource is not allowed to be idle as long as there is an unfinished job in the system. While describing the advantages and weaknesses of the existing scheduling solutions we show that using online non-work-conserving algorithms it is possible to schedule more task sets. In our work, we discuss the challenges to design the idle-time insertion policy (IIP) which can be combined with the existing scheduling policies such as the earliest deadline first (EDF), rate monotonic (RM), etc. Further we present a tighter necessary condition for schedulability of non-preemptive tasks. We also provide an IIP for EDF based on looking into a number of jobs in future. Through the experiments we show that the our IIP for EDF significantly increases the schedulability of non-preemptive tasks, particularly in periodic task sets. While our schedulability ratio is more than 80%, the state of the art work-conserving algorithms are about 15%.

关键词： scheduling algorithms Harmonic analysis Concrete Real-time systems scheduling Schedules Optimal scheduling

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Poster Abstract: Online Semi-Partitioned Multiprocessor scheduling of Soft Real-Time Periodic Tasks for QoS Optimization

Poster Abstract: Online Semi-Partitioned Multiprocessor Sche...

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IEEE Symposium on Real-Time and Embedded Technology and Applications

作者： Behnaz Sanati Albert M. K. Cheng Department of Computer Science University of Houston Texas USA

Summary form only given. Multiprocessor real-time scheduling algorithms may follow a partitioned or global approach or some hybrid of the two, called semi-partitioning. Semi-partitioned real-time scheduling algorithms extend partitioned ones by allowing a subset of tasks to migrate. Given the goal of “less overhead”, it is desirable for such strategy to be boundary-limited, and allow a migrating task to migrate only between successive invocations (job boundaries). Non-boundary-limited schedulers allow jobs to migrate, which can be expensive in practice, if jobs maintain much cached state. Previously proposed semi-partitioned algorithms for soft real-time (SRT) tasks such as EDF-fm and EDF-os, have two phases: an offline assignment phase, where tasks are assigned to processors and fixed tasks (which do not migrate) are distinguished from migrating ones; and an online execution phase. In their execution phase, rules that extend EDF scheduling are used. These strategies aim to minimize tardiness. In this paper, we propose a new online reward-based semi-partitioning approach to schedule periodic soft real-time tasks in homogeneous multiprocessor systems. We use an online choice of two approximation algorithms, Greedy and Load-Balancing, for partitioning, which provides an optimized usage of processing time. In this method, no prior information is needed. Hence, there is no offline phase. Our objective is to enhance the QoS by minimizing tardiness and maximizing the total reward obtained by completed tasks in minimum makespan. Therefore, we allow different jobs of any task get assigned to different processors (migration at job boundaries) based on their reward-based priorities and workload of the processors. This method can also extend to direct SRT systems with mixed set of tasks (aperiodic, sporadic and periodic) by defining their deadline accordingly. Many real-time applications can benefit from this solution including but not limited to video streaming servers, multi

关键词： Real-time systems Program processors Quality of service scheduling algorithms Optimization Computer science

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scheduling algorithm for BLE sensors using binary trees to reduce gaps in collected data

Scheduling algorithm for BLE sensors using binary trees to r...

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International Conference on Computer Engineering and Systems

作者： Amr El Mougy George Sedky Mohamed Assem Faculty of Media Engineering and Technology Faculty of Information Engineering and Technology German University in Cairo Cairo Egypt

ISBN: (纸本)9781509032686

One of the leading technologies for the Internet of Things (IoT) is Bluetooth Low Energy (BLE), whose broadcast mode has very low energy consumption. Typically, data transmitted by BLE sensors would be collected by smartphones within their range and uploaded to the cloud. In this case, there is a probability that sensor data is lost if there are no smartphones present at the time of transmission. Eventually, this may cause significant gaps in the data collected at the cloud. This paper addresses this challenge through a novel scheduling algorithm for BLE sensors that uses binary trees to reduce the gaps in collected data, while considering varying smartphone density. The algorithm is evaluated using computer simulations and a hardware prototype is implemented. The evaluations illustrate that gaps are indeed reduced in the collected data, and shows how the parameters of the protocol can be configured in different conditions.

关键词： scheduling algorithms Smart phones scheduling Cloud computing Sensor phenomena and characterization Clouds

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An End-to-End Delay-based scheduling Algorithm in IEEE 802.15.4e Networks

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INTERNATIONAL JOURNAL OF FUTURE GENERATION COMMUNICATION AND NETWORKING 2016年第7期9卷 287-295页

作者： Kim, Yang G. Park, ByoungSeob Choi, Hyo Hyun CUNY New York City Coll Technol Dept Comp Engn Technol 300 Jay St Brooklyn NY 11210 USA Inha Tech Coll Dept Comp Syst & Engn 100 Inha Ro Inchon 402752 South Korea Inha Tech Coll Dept Comp Sci 100 Inha Ro Inchon 402752 South Korea

This paper proposes a novel scheduling algorithm using multi-channel and multi-timeslot with the objective of reducing the end-to-end (e2e) delay in a tree-based wireless sensor network. The algorithm exploits a staggered timeslot allocation in terms of e2e paths, rather than the one with individual branches. It also increases simultaneous data transmissions. The proposed algorithm is shown to be superior to an existing algorithm with non-e2e delay based, in terms of e2e delay.

关键词： Multi-channel multi-timeslot multi-hop scheduling algorithms end-to-end delay wireless sensor networks

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A New Approach for Limited Preemptive scheduling in Systems with Preemption Overhead

A New Approach for Limited Preemptive Scheduling in Systems ...

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Euromicro Conference on Real-Time Systems

作者： Mitra Nasri Geoffrey Nelissen Gerhard Fohler Dept. of Real-time Syst. Tech. Univ. Kaiserslautern Germany Instituto Politecnico do Porto Instituto Superior de Engenharia do Porto Porto Porto PT

ISBN: (纸本)9781509028122

This paper considers the problem of reducing the number of preemptions in a system with periodic tasks and preemption overhead. The proposed solution is based on the key observation that for periodic task sets, the task with the smallest period plays an important role in determining the maximum interval of time during which a lower priority task can be executed without being preempted. We use this property to build a new limited preemptive scheduling algorithm, named RS-LP, based on fixed-priority scheduling. In RS-LP, the length of each task's non-preemptive region is varying during the system execution so as to keep the preemptions aligned with the releases of the highest priority task. This simple mechanism allows us to reduce the overall number of preemptions. The proposed algorithm, decides whether or not to preempt the currently executing task based on the maximum blocking tolerance of the higher priority tasks. In any case, the preemptions are authorized only at release instants of the task with the smallest period, thereby limiting the maximum number of preemptions to the number of releases of the highest priority task. Moreover, in this paper, we provide two different preemption overhead aware schedulability tests for periodic and loose-harmonic task sets (i.e., where each period is an integer multiple of the smallest period), together with a lower bound on the maximum number of preemptions. To conclude, extensive experiments comparing RS-LP with the state of the art limited preemptive scheduling algorithms are finally presented.

关键词： Real-time systems scheduling algorithms scheduling Servers Mathematical model Aerospace electronics

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An embedded prototype of a residential smart appliance scheduling system

An embedded prototype of a residential smart appliance sched...

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International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： Chris Ogwumike Michael Short Fathi Abugchem School of Science and Engineering Teesside University Middlesborough United Kingdom

ISBN: (纸本)9781509013159

Demand Response (DR) is seen as one of the key enabling factors in the emerging smart grid. DR takes many forms, including residential smart appliance scheduling. scheduling algorithms capable of achieving near-minimum cost solutions with low computational overhead are required in order to autonomously respond to varying utility pricing signals. In this paper, the focus is upon an embedded software prototype implementation of a residential load scheduling system. It describes the implementation and testing of a heuristic algorithm for household energy management on a small embedded processor. The performance of the prototype implementation is validated against previously reported experiments and simulations. Test results indicate that the heuristic is efficient enough to be co-located on a small smart meter with limited memory and processing power without any difficulties, helping to open the way for practical consumer demand response.

关键词： Home appliances Smart meters MATLAB scheduling algorithms Heuristic algorithms scheduling

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Efficient Antenna Selection and User scheduling in 5G Massive MIMO-NOMA System

Efficient Antenna Selection and User Scheduling in 5G Massiv...

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IEEE Vehicular Technology Conference

作者： Xin Liu Xianbin Wang Department of Electrical and Computer Engineering The University of Western Ontario

ISBN: (纸本)9781509016990

To achieve extremely high spectral efficiency in the 5-th generation (5G) communication network, the combination of massive multiple input multiple output (MIMO) and non-orthogonal multiple access (NOMA) technologies becomes a promising solution. However, due to limited radio frequency (RF) chains and channel condition variation, it is important to develop efficient antenna selection and user scheduling algorithms in complex MIMO-NOMA system. In this paper, efficient antenna selection and user scheduling algorithms are investigated to maximize the sum rate in two MIMO-NOMA scenarios. In the first simple single-band two-user scenario, the proposed antenna selection algorithm achieves higher search efficiency by limiting the candidate antennas to those are beneficial to the relevant users. In the multi-band multi-user scenario, the proposed joint antenna and user (AU) contribution algorithm considers the contribution of each antenna's and user's channel gain to total channel gain jointly. Numerical results show that proposed antenna selection algorithm achieves near-optimal performance, and joint AU contribution algorithm achieves similar performance to existing methods with reduced complexity.

关键词： ANTENNA scheduling algorithms selection algorithm antennae multiple input multiple output systems Consumers Gold African Union ASTRONOMICAL UNIT Gain radiofrequency

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A new link weight factor in backpressure scheduling algorithm for energy-efficient design of Smart Wireless Sensor Networks

A new link weight factor in backpressure scheduling algorith...

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IEEE International Conference on Smart Energy Grid Engineering (SEGE)

作者： Fawaz Alassery Computer Engineering Department Taif University Taif Saudi Arabia

In Smart Wireless Sensor Networks, it is imperative to utilize the most power efficient techniques to prolong the lifetime of a sensor node. Backpressure based scheduling has a remarkable performance for smart WSNs, and it has been discussed extensively in literatures. However, considering the energy efficiency of Backpressure scheduling algorithms for recourse-constrained smart WSNs is still need to be studied in order to design smart WSNs with minimum energy consumption. Unlike previous works for Backpressure scheduling algorithms, in this paper we propose a novel Multi-Factors Backpressure scheduling (MFBS) algorithm which focuses on introducing new link-weights for energy efficient scheduling in smart WSNs. In MFBS, besides queue backlog differentials which is the common scheduling method in the classical Backpressure algorithm, nodal residual energy as well as the shortest path between neighbors (nodes) are also jointly considered into the transmission scheduling decision. Based on the results of our extensive simulation which is proven by the equivalent theoretical analysis, MFBS shows a significant improvement in the network performance of smart WSNs in terms of the network lifetime, the throughput, the queue length and the energy-efficiency in comparison with existing algorithms such as the classical backpressure algorithm and enhanced dynamic backpressure routing algorithm.

关键词： Wireless sensor networks scheduling algorithms Heuristic algorithms Algorithm design and analysis scheduling Energy efficiency Routing

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Value of Service Based Task scheduling for Cloud Computing Systems

Value of Service Based Task Scheduling for Cloud Computing S...

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International Conference on Cloud and Autonomic Computing (ICCAC)

作者： Cihan Tunc Nirmal Kumbhare Ali Akoglu Salim Hariri Dylan Machovec Howard Jay Siegel NSF Center for Cloud and Autonomic Computing University of Arizona Tucson Arizona USA Department of Electrical and Computer Engineering Department of Computer Science Colorado State University Fort Collins Colorado USA

ISBN: (纸本)9781509035373

Task scheduling for large scale computing systems is a challenging problem. From the users' perspective, the main concern is the performance of the submitted tasks, whereas, for the cloud service providers, reducing cost while providing the required service is critical. Therefore, there is a need for task scheduling mechanisms that balance users' performance requirements while being energy efficient. We present a time dependent Value of Service (VoS) metric that takes into consideration the arrival time of a task while evaluating the value of completing a task within its deadline and its energy consumption within a constraint. We consider the variation in value for completing a task at different times such that the value of energy reduction can change significantly between peak and non-peak periods. We use completion time and energy based value functions with soft and hard thresholds. Thus, we define the VoS for a given workload to be the sum of the values for all tasks that are executed during a given period of time. Our system model is based on virtual machines (VMs), where each task will be assigned a resource configuration characterized by the number of the homogeneous cores and amount of memory. Using VoS, we design, evaluate, and compare our task scheduling methods to show a significant improvement in energy consumption when considering time-of-use dependent scheduling algorithms. The experimental results are run on an IBM blade server using KVM. The experimental results show using time dependent VoS, 50% improvement in performance value, 40% improvement in energy value, and up to 91% improvement in VoS over a heuristic that only considers only the hard threshold of the value functions.

关键词： Energy consumption Cloud computing Measurement Resource management scheduling algorithms scheduling

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Service Priority Dependent Vehicle To Hotspot Communication Opportunistic scheduling

Service Priority Dependent Vehicle To Hotspot Communication ...

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IEEE International Conference on Industrial and Information Systems

作者： Riya Bansal Anurag Shrivastava Anjulata Yadav Department of Electronics and Telecommunication SGSITS Indore (M.P.) India

Vehicular communication system is highly dynamic system. The scheduling algorithm plays an important role in providing the maximum service to the vehicular users. Various types of services may be provided to the vehicle on request like audio/video entertainment, map information (Hotels, shops etc.), routing information and emergency information like Hospital, Police and Traffic congestion etc. Due to limited number of channels and limited time for data transmission, service priority is required for transmission. Further the service time optimization is required depending upon the maximum possible speed of a vehicle. In this paper, an opportunistic scheduling algorithm with service priority and holding users are proposed. The concept of holding users enhances the service fairness and maximum services provided by hotspot. The simulation results show the clear advantage of proposed opportunistic scheduling algorithm over existing priority based NDS algorithm.

关键词： scheduling algorithms Signal to noise ratio Unicast Throughput Safety Nickel scheduling

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