Make Scheduling Decisions Research Articles

An exploration of online-simulation-driven portfolio scheduling in Workflow Management Systems

Workflow Management Systems used to automate the execution of scientific workflow applications on parallel and distributed computing platforms must make scheduling decisions at runtime. A large number of workflow scheduling algorithms have been proposed in the literature, but often these algorithms are evaluated based on simplifying assumptions that may not hold in practice. Furthermore, published algorithm evaluation and/or comparison results are necessarily only for a subset of all possible scenarios, and thus may not include scenarios relevant to particular use-cases. Consequently, it is difficult for Workflow Management Systems (WMSs) developers to decide which scheduling algorithm should be implemented. To obviate this difficulty, one possible approach is to implement a portfolio of scheduling algorithms and select the most effective algorithm at runtime. One method for performing this selection is to run an online simulation for each algorithm in the portfolio. The algorithm that leads to the best performance, in simulation, is selected for future use.The above simulation-driven portfolio scheduling (SDPS) approach has been proposed in a few parallel and distributed computing contexts. The main objective of this work is to evaluate the feasibility and potential merit of SDPS if implemented in WMSs. We perform this evaluation using simulated WMS executions, where the simulations are instantiated from real-world platform and workflow configurations. Our main finding is that SDPS is on par with or outperforms an approach in which a single algorithm is used, where this algorithm is the one that performs best on average across all our experimental scenarios. Furthermore, we find that SDPS remains an attractive proposition even in the presence of high levels of simulation error and for simulators with relatively low levels of sophistication. In many of our experimental scenarios we find that mitigating simulation error at runtime can further improve performance. Finally, we show that simulation overhead can be made sufficiently low for SDPS to be feasible in practice.

Adaptive Transmissions for Batteryless Periodic Sensing

Batteryless, self-sustaining embedded sensing devices are key enablers for scalable and long-term operations of Internet of Things (IoT) applications. While advancements in both energy harvesting and intermittent computing have helped pave the way for building such batteryless IoT devices, a present challenge is a system design that can utilize intermittent energy to meet data requirements from IoT applications. In this paper, we take the requirement of periodic data sensing and describe the hardware and software of a batteryless IoT device with its model, design, implementation, and evaluation. A key finding is that, by estimating the non-linear hardware charging and discharging time, the device software can make scheduling decisions that both maintain the selected sensing period and improve transmission goodput. A hardware–software prototype was implemented using an MSP430 development board and LoRa radio communication technology. The proposed design was empirically compared with one that does not consider the non-linear hardware characteristics. The result of the experiments illustrated the nuances of the batteryless device design and implementation, and it demonstrated that the proposed design can cover a wider range of feasible sensing rates, which reduces the restriction on this parameter choice. It was further demonstrated that, under an intermittent supply of power, the proposed design could still keep the device functioning as required.

Fractional Deep Reinforcement Learning for Age-Minimal Mobile Edge Computing

Mobile edge computing (MEC) is a promising paradigm for real-time applications with intensive computational needs (e.g., autonomous driving), as it can reduce the processing delay. In this work, we focus on the timeliness of computational-intensive updates, measured by Age-of-Information (AoI), and study how to jointly optimize the task updating and offloading policies for AoI with fractional form. Specifically, we consider edge load dynamics and formulate a task scheduling problem to minimize the expected time-average AoI. The uncertain edge load dynamics, the nature of the fractional objective, and hybrid continuous-discrete action space (due to the joint optimization) make this problem challenging and existing approaches not directly applicable. To this end, we propose a fractional reinforcement learning (RL) framework and prove its convergence. We further design a model-free fractional deep RL (DRL) algorithm, where each device makes scheduling decisions with the hybrid action space without knowing the system dynamics and decisions of other devices. Experimental results show that our proposed algorithms reduce the average AoI by up to 57.6% compared with several non-fractional benchmarks.

Data-driven-based distributionally robust optimization approach for a virtual power plant considering the responsiveness of electric vehicles and Ladder-type carbon trading

To encourage the utilization of decentralized renewable energy systems, a data-driven-based distributionally robust optimization (DRO) model is proposed for a virtual power plant (VPP) considering the responsiveness of electric vehicles (EVs) and a ladder-type carbon trading mechanism (LT-CTM). An EV virtual energy storage (EV-VES) calculation model for dispatchable power is formulated to facilitate the centralized scheduling of EVs, considering responsiveness and spatial–temporal distribution characteristics. Additionally, multiple kinds of energy storage systems and flexible loads are considered in the VPP. Furthermore, to handle multiple uncertainties for both the renewable energy and load, Latin hypercube sampling is applied to generate the renewable energy scenarios, and K-means clustering is used to obtain typical scenes. Then the DRO model is used to solve the dispatch problem. An LT-CTM is leveraged to reduce carbon emissions. The column and constraint generation algorithm is then employed to identify an optimal operational benefit solution. Finally, a multi-parameter coupling analysis of ladder-type carbon trading is used for the environmental protection and economy of the VPP. The results confirm the efficacy of the proposed day-ahead scheduling model, offering a theoretical reference for operators when making scheduling decisions.

Probing an Easy-to-Deploy Multi-Agent Manufacturing System Based on Agent Computing Node: Architecture, Implementation, and Case Study

Abstract Due to the widespread adoption of personalized customization services, the application contexts within discrete manufacturing workshops have become increasingly intricate, necessitating the modern industry to evolve toward a more adaptable production trajectory. The pre-established production rules in a traditional centralized control manufacturing system present difficulties in accommodating dynamic situations. Although a multi-agent manufacturing system (MAMS) yields natural advantages in handling dynamic emergencies, the current research is limited to the computer simulation level and lacks integration with the underlying physical devices. In order to mitigate said challenges, the standardization modeling approach for the agent computing node (ACN) to facilitate the implementation of a readily deployable MAMS was proposed in the present study. Initially, adapters encompassing communication, decision, and control modules were developed within the industrial personnel computer-based computing node to accommodate the heterogeneous interface protocols of diverse machines. These adapters enable communication and interaction among machines while laying the computational foundation for the ACN. Accordingly, the models of the machine agent, the part agent, and the monitoring agent were constructed based on ACNs and could perceive the dynamic production information and support the enabling application. Subsequently, to guide ACNs in making scheduling decisions beneficial to global performance, an improved negotiation mechanism in MAMS was achieved in real-time. Finally, the proposed MAMS based on the ACN was deployed in an actual flexible machining workshop. Comparative experiments were implemented and, as exhibited from the experimental results, the proposed ACNs possessed the capabilities of achieving optimal global decision-making and facilitating straightforward deployment.

Low-delay cost-aware multipath scheduling over dynamic links for access traffic steering, switching, and splitting

Bundling of multiple access technologies is currently being standardized by 3GPP in the 5G access traffic steering, switching and splitting (ATSSS) framework, with the goal to increase robustness, resiliency and capacity of wireless access. A key part of an ATSSS framework is the packet scheduler, which decides the access network over which each packet is to be transmitted. As wireless channels are highly dynamic, a challenge for any scheduler is to correctly estimate the capacity of each path, and thereby avoid congesting the paths. In this paper, we further develop a recent packet scheduler that exploits cross-layer information from the congestion control state of individual transport layer tunnels when making scheduling decisions. Our aim is to achieve good path utilization while keeping the congestion delay low. Extensive emulations show that our approach reduces the excess delay at the bottleneck to as little as 34%. We furthermore show that our approach improves the performance of end-to-end applications including WebRTC and YouTube compared to state-of-the art.

Energy-efficient Neuro-fuzzy-based Multi-node Charging Model for WRSNs using Multiple Mobile Charging Vehicles

Mobile charging vehicles (MCVs) have played a significant role in advancing Wireless Rechargeable Sensor Networks (WRSNs). Recent research has primarily focused on on-demand charging in WRSNs using MCVs. However, minimal attention has been given to the simultaneous analysis of multiple MCVs with multi-node energy transfer capabilities. Additionally, when making scheduling decisions, most existing methods still need to consider various network parameters, while a few have overlooked the challenge of sensor nodes’ (SNs) poor charging responses to non-uniform energy expenditure rates. This article addresses the issues above and proposes an innovative charging-scheduling Algorithm based on Neuro-fuzzy with PSO model (ANFIS-PSO) to resolve these challenges. To ensure uniform workload allocation among MCVs and prevent interference during the charging process, we deploy MCVs strategically using the Optimal Fuzzy C-Means clustering method. We then optimize MCV visiting points to recharge energy-critical SNs, implying reduced energy consumption and charging delay. We next adopt the ANFIS-PSO model, which blends various network parameters for creating the charging schedules of the MCVs. We devise an expression to find the SNs’ adaptive charging threshold values based on their remaining lifetime. We also formulate another expression called the average charging weight function to assist the ANFIS-PSO model in selecting the next promising SN for recharging. Experimental simulations validates that our method is effective and outperforms baseline methods, with a substantial 11% reduction in charging delay, a 6% improvement in the life-survival ratio, and a 7% increase in energy utilization efficiency across all performance metrics.

Two-time scale dynamic closed-loop scheduling for gas supply network with multiple air separation units

The gas supply network with multiple air separation units (ASUs) in steel enterprises provides the essential gas products for iron- and steel-making processes. Steel enterprises must make scheduling decisions for their gas supply networks to meet the fast-changing downstream demands. Therefore, the dynamic characteristics of the process must be considered during short-interval production scheduling to ensure more reasonable scheduling decisions. A two-scale dynamic scheduling method is first developed in this paper to consider the process dynamics. In this method, scheduling decisions are made in the slow time scale, and the nonlinear dynamic characteristics are described using a varied time constant dynamic model in the fast time scale. Then, an autoregressive moving average (ARMA) model is established to address the unavoidable model mismatch, which explicitly predicts and integrates future mismatches into the scheduling model. Moreover, a moving horizon closed-loop framework is designed to integrate the state feedback, mismatch modeling, and scheduling decision modification so that scheduling decisions can be modified in real time to avoid potential safety hazards. The results of the industrial application indicate that the proposed method can provide better scheduling decisions in case studies of model mismatch and unknown leakage compared with existing methods.

Mobility and Deadline-Aware Task Scheduling Mechanism for Vehicular Edge Computing

Vehicular Edge Computing (VEC) is a promising paradigm that provides cloud computing services closer to vehicular users. In VEC, vehicles and communication infrastructures can form pools with computational resources to meet vehicular services with low-latency constraints. These resource pools are known as Vehicular Cloud (VC). The usage of VC resources requires a task scheduling process. In this case, depending on its complexity, a vehicular service can be divided into different tasks. An efficient task scheduling needs to orchestrate where and for how long such tasks will run, considering the available pools, the mobility of nodes, and the tasks deadline constraints. Thus, this article proposes an efficient VC task scheduler based on an approximation heuristic and resources prediction to select the best VC for each task, called MARINA. MARINA aims to analyze the behavior of vehicles that share their computational resources with the VC and make scheduling decisions based on the mobility (VC availability) of these vehicles. Simulation results under a realistic scenario demonstrate the efficiency of MARINA compared to existing state-of-the-art mechanisms in terms of the number of tasks scheduled, monetary cost, system latency, and Central Processing Unit (CPU) utilization.

Two-Level Scheduling Algorithms for Deep Neural Network Inference in Vehicular Networks

In vehicular networks, task scheduling at the microarchitecture-level and network-level offers tremendous potential to improve the quality of computing services for deep neural network (DNN) inference. However, existing task scheduling works only focus on either one of the two levels, which results in inefficient utilization of computing resources. This paper aims to fill this gap by formulating a two-level scheduling problem for DNN inference tasks in a vehicular network, with an objective of minimizing total weighted sum of response time and energy consumption for all tasks under the following constraints: per task response time, per vehicle energy consumption, per vehicle storage capacity. We first formulate the problem and prove that it is NP-hard. A group transformation based algorithm, called GTA, is proposed. GTA makes scheduling decisions at the network-level using the group transformation based approach, and at the microarchitecture-level using a greedy strategy. In addition, an algorithm, denoted as DRL, is proposed to decrease total weighted sum of response time and energy consumption for all tasks. DRL trains two models with deep reinforcement learning to achieve two-level scheduling. The proposed algorithms are evaluated on a platform consisting of a desktop, Raspberry Pi, Eyeriss, OSM, SUMO, NS-3. Simulation results show that DRL outperforms the state-of-the-art methods for all cases, while the proposed GTA outperforms the state-of-the-art methods for most cases, in terms of total weighted sum of response time and energy consumption. Compared with four baseline algorithms, GTA and DRL reduce the total weighted sum of response time and energy consumption by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$41.49\%$</tex-math> </inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$62.38\%$</tex-math> </inline-formula> , on average respectively, for different numbers of tasks.

Minimizing the mean slowdown in the M/G/1 queue

We consider the optimal scheduling problem in the M/G/1 queue. While this is a thoroughly studied problem when the target is to minimize the mean delay, there are still open questions related to some other objective functions. In this paper, we focus on minimizing mean slowdown among non-anticipating polices, which may utilize the attained service of the jobs but not their remaining service time when making scheduling decisions. By applying the Gittins index approach, we give necessary and sufficient conditions for the jobs’ service time distribution under which the well-known scheduling policies first come first served and foreground background are optimal with respect to the mean slowdown. Furthermore, we characterize the optimal non-anticipating policy in the multi-class case for certain types of service time distributions. In fact, our results cover a more general objective function than just the mean slowdown, since we allow the holding costs for a job to depend on its own service time S via a generic function c(S). When minimizing the mean slowdown, this function reads as c(x) = 1/x.

A priority rule for scheduling shared due dates in the resource-constrained project scheduling problem

In resource-constrained project scheduling, project milestones, rental equipment, contracted labor, and product development checkpoints all conceptually impose shared due dates, which expand the concept of conventional due dates by permitting their assignment to sets of activities and by allowing multiple shared due date assignments, or none at all, to a single activity. Existing heuristic algorithms in the literature that solve the resource-constrained project scheduling problem are agnostic to shared due dates and cannot utilize information about their assignments in making scheduling decisions. To this end, we propose a novel priority rule compatible with both serial and parallel schedule generation schemes that integrates shared due date information into the heuristic scheduling decisions. We evaluate the effectiveness of our priority rule by demonstrating its dominance over existing priority rules in the literature and by comparing its performance with an exact algorithm. In comparing with the latter, we demonstrate both the computational efficiency of the heuristic as well as the quality of the solutions it produces.

Optimizing Age of Information in Wireless Uplink Networks With Partial Observations

This paper considers a wireless uplink network consisting of multiple end devices and an access point (AP). Each device monitors a physical process with randomly generated status updates and sends these update packets to the AP in the uplink. The AP aims to schedule the transmissions of these devices to optimize the network-wide information freshness, quantified by the age of information (AoI) metric. Due to the stochastic arrival of the status updates at end devices, the AP only has partial observations of system times of the latest status update packets at end devices when making scheduling decisions. Such a decision-making problem can be naturally formulated as a partially observable Markov decision process (POMDP). We reformulate the POMDP into an equivalent belief Markov decision process (belief-MDP), by defining fully observable belief states of the POMDP as the states of the belief-MDP. The belief-MDP in its original form is difficult to solve as the dimension of its states can go to infinity and its belief space is uncountable. Fortunately, by carefully leveraging the properties of the status update arrival processes (i.e., Bernoulli processes), we manage to simplify the belief-MDP substantially, where every feasible state is characterized by a two-dimensional vector. Based on the simplified belief-MDP, we devise a low-complexity scheduling policy, termed Partially Observing Max-Weight (POMW) policy, for the formulated AoI-oriented scheduling problem. We derive upper bounds for the time-average AoI performance of the proposed POMW policy. We analyze the performance guarantee for the POMW policy by comparing its performance with a universal lower bound available in the literature. Numerical results validate our analyses and demonstrate that the performance gap between the POMW policy and its fully observable counterpart is proportional to the inverse of the lowest arrival rate of all end devices.

Workflow Scheduling in Serverless Edge Computing for the Industrial Internet of Things: A Learning Approach

Serverless edge computing is seen as a promising enabler to execute differentiated Industrial Internet of Things (IIoT) applications without managing the underlying servers and clusters. In IIoT serverless edge computing, IIoT workflow scheduling for cloud-edge collaborative processing is closely related to the service quality of users. However, serverless functions decomposed by IIoT applications are limited in their deployment at the edge due to the resource-constrained nature of edge infrastructures. Additionally, the scheduling of complex IIoT applications supported by serverless computing is more challenging. Therefore, considering the limited function deployment and the complex dependencies of serverless workflows, we model the workflow application as Directed Acyclic Graph (DAG) and formulate the scheduling problem as a multi-objective optimization problem. A Dueling Double Deep Q-Network (D3QN)-based solution is proposed to make scheduling decisions under dynamically changing systems. Extensive simulation experiments are conducted to validate the superiority of the proposed scheme.

A DRL based approach for adaptive scheduling of one-of-a-kind production

Adaptive scheduling is an efficient strategy for one-of-a-kind production (OKP) widespread in heavy industries to address its challenges of the high degree of customization and frequent interference. However, the scheduling procedure meets the problems of complex constraints and short decision time. To address these issues, this study aims to develop a reinforcement learning-based algorithm to solve the adaptive scheduling problem of OKP. The objective is to minimize the makespan. Firstly, the OKP adaptive scheduling problem is modeled as a Markov decision process, and a reinforcement learning algorithm is used to train the scheduling agent offline. Then, the trained agent can make scheduling decisions adaptively according to the production state in a short time. To evaluate the effectiveness of the proposed algorithm, a large number of numerical experiments are performed on the benchmark datasets and a practical engineering case. The results show that the proposed algorithm is competitive in static testing. And it can also achieve the balance between scheduling performance and computation time during adaptive scheduling.

Information Freshness in Multihop Wireless Networks

We consider the problem of minimizing age of information in multihop wireless networks and propose three classes of policies to solve the problem - stationary randomized, age difference, and age debt. For the unicast setting with fixed routes between each source-destination pair, we first develop a procedure to find age optimal Stationary Randomized policies. These policies are easy to implement and allow us to derive closed-form expression for average AoI. Next, for the same unicast setting, we develop a class of heuristic policies, called Age Difference, based on the idea that if neighboring nodes try to reduce their age differential then all nodes will have fresher updates. This approach is useful in practice since it relies only on the local age differential between nodes to make scheduling decisions. Finally, we propose the class of policies called Age Debt, which can handle 1) non-linear AoI cost functions; 2) unicast, multicast and broadcast flows; and 3) no fixed routes specified per flow beforehand. Here, we convert AoI optimization problems into equivalent network stability problems and use Lyapunov drift to find scheduling and routing schemes that stabilize the network. We also provide numerical results comparing our proposed classes of policies with the best known scheduling and routing schemes available in the literature for a wide variety of network settings.

Jitter‐sensitive data communication in emerging wireless networks

AbstractJitter and time‐sensitive communications (TSC) will play an important role as part of the emerging wireless networks such as fifth‐generation (5G) and sixth‐generation (6G) cellular networks to enable applications including vehicle‐to‐everything (V2X), real‐time audio/video, real‐time industrial automation and control, and synchronized collaboration. TSC is characterized by stringent latency, jitter, and reliability requirements. This paper considers the problem of scheduling time‐sensitive data packets with stringent playout deadlines over a downlink multiple‐input multiple‐output (MIMO) channel, as part of the emerging wireless networks, to minimize the average jitter of a data session. Even though extensive research has been performed on MIMO technology, jitter and time‐sensitive data communication over a MIMO channel remains an under‐studied problem. In the proposed model, early or late arrival of the packets with respect to their playout deadlines incurs an early‐ or late‐arrival penalty, respectively. The proposed scheduling problem is proven to be NP‐hard and three computationally‐efficient scheduling heuristics are developed with varying performance and computational tradeoffs. These heuristics make packet scheduling decisions over the MIMO subchannels with the objective of minimizing the average jitter value of the data session. While making scheduling decisions, these heuristics intelligently take into consideration the playout deadlines and size of the packets, the time‐varying channel conditions, and the cost of the early or late arrival of the packets. The performance of these heuristics is evaluated from a design perspective through extensive simulations. The simulation results provide key insights into the relative performance tradeoffs among the three heuristics as a function of the various system parameters. This information could be utilized in intelligently allocating system resources to obtain the desired optimal system performance.

Offloading Elastic Transfers to Opportunistic Vehicular Networks Based on Imperfect Trajectory Prediction

Due to the high cost of cellular networks, vehicle users would like to offload elastic traffic through vehicular networks as much as possible. This demand prompts researchers to consider how to make the vehicular network system achieve better performance for requests coming online, such as maximizing throughput. The traffic in vehicular networks is transferred through opportunistic contacts between vehicles and infrastructures. When making scheduling decisions, the scheduler must be aware of vehicles’ future trajectories. Vehicles’ future trajectories are usually predicted by trajectory prediction algorithms when users are unwilling to report their future trips. Unfortunately, no trajectory prediction algorithm can be completely accurate, and these inaccurate prediction results will degrade the throughput achieved by scheduling algorithms. In this paper, we focus on reducing the negative impact of inaccurate predictions. Specifically, we measure two data-driven trajectory prediction algorithms that have been widely used for trajectory predictions and understand the characteristics of the accuracy of predicted contacts. Based on the enlightenment from the measurement, we design a system, i.e., i-Offload, to offload elastic traffic under imperfect trajectory predictions. The experimental results show that our system has good throughput and high scheduling efficiency even under imperfect trajectory predictions. Compared with existing scheduling algorithms, our method improves the throughput by about one time.

Low Latency and High Data Rate (LLHD) Scheduler: A Multipath TCP Scheduler for Dynamic and Heterogeneous Networks.

The scheduler is a crucial component of the multipath transmission control protocol (MPTCP) that dictates the path that a data packet takes. Schedulers are in charge of delivering data packets in the right order to prevent delays caused by head-of-line blocking. The modern Internet is a complicated network whose characteristics change in real-time. MPTCP schedulers are supposed to understand the real-time properties of the underlying network, such as latency, path loss, and capacity, in order to make appropriate scheduling decisions. However, the present scheduler does not take into account all of these characteristics together, resulting in lower performance. We present the low latency and high data rate (LLHD) scheduler, which successfully makes scheduling decisions based on real-time information on latency, path loss, and capacity, and achieves around 25% higher throughput and 45% lower data transmission delay than Linux's default MPTCP scheduler.

A space variable-scale scheduling method for digital vehicle-to-grid platform under distributed electric energy storage

With the widespread application of digital technology in the intelligent transportation field, the vehicle-to-grid (V2G) pattern, which utilizes electric vehicles (EVs) as the distributed storage resources of electric energy, has won increasingly more attention from authorities and decision-makers to promote the sustainable development of regenerative clean energy. This paper aims to study the interaction and integration problem between EVs and grid for the digital V2G platform, so as to support load aggregators making scheduling decisions. According to the variable-scale data analysis theory, a space–time scale space model is established to describe the demand response behavioral feature of EV users, and the lightning-Scale Transformation method (LST) is also proposed. Compared to the original unidirectional scale transformation modes, the LST is capable of adjusting the space and time observation scale collaboratively. A vehicle-to-grid scheduling method based on the lightning-Scale Transformation (V2G-LST) is put forward, in order to make scheduling plans by considering EV users’ behavioral feature and charger resource constraints. We collect the real dataset from 863 Beijing charging stations using the APIs of Amap, as well as the investigation data of the State Grid Corporation of China to verify the efficacy of our proposed method. Comparative experimental results verify that the V2G-LST could obtain the lower dispatch cost and higher EV charger usage rate than the maximum dispatchable quantity first method EVC-MDQ under both charging and discharging scenarios.