Segment Scheduling Research Articles

A multi-objective segmentation scheduling method for the flexible dismantling of retired power batteries taking into account transfer time

Decommissioned power batteries are prone to dilapidated deformation, which makes it difficult to carry out unified and efficient production scheduling for disassembly production. In this paper, a multi-objective scheduling method applied to the dismantling workshop of retired power batteries is presented. For the characteristics of power battery dismantling, a strategy of scheduling by a battery pack and battery module in stages is proposed. The multi-objective optimal scheduling model of the dismantling workshop is established with the decision objectives of reducing the time of completion, energy dissipation and workstation load, taking into account the transfer time of batteries in the dismantling process, and is solved by genetic algorithm. The chromosome coding method, the crossover variation method and the elite retention strategy in the genetic algorithm were optimized. The method is applied to the dismantling examples of 5 kinds of power batteries, and the simulation results show that the proposed method is feasible and effective.

6TiSCH Low Latency Autonomous Scheduling for Industrial Internet of Things

With the advancements in the Internet of Things (IoT), machine-to-machine communication, big-data, and the associated environment, a new model of the Industrial Internet of Things (IIoT) has emerged. The IIoT brings sensors, intelligent machines and tools, instruments, and analytics together for applications like manufacturing, robotics, and many others. Most of these applications require adaptive and autonomous behavior, Quality of Service (QoS), efficient resource allocation, and reservation. One of these crucial challenges is to build and maintain a data communication schedule. Time Slotted Channel Hopping (TSCH) based network operation promises required QoS for low-power applications and enables high reliability. 6TiSCH layer is being developed by standardizing the protocol stack to achieve industrial performance requirements by using IPv6 over IEEE802.15.4e TSCH MAC. 6TiSCH aims to manage the schedule and configure it with the topology and traffic requirements in the industrial environment. This paper proposes a novel low latency autonomous scheduling scheme for the 6TiSCH networks. It generates a segmented schedule for the network where all source nodes can send application data packets to the root node in a single slotframe. The performance of the proposed technique is compared with existing scheduling techniques. Our scheme outperforms the other techniques. The result shows that the latency is reduced up to 41% in comparison with the other scheduling schemes. The proposed scheme has a lower radio duty cycle as the node’s ON time is reduced, making it more energy efficient and reliable.

Segment Scheduling Scheme for Efficient Bandwidth Utilization of HTTP Adaptive Streaming in Multipath Environments

HyperText Transfer Protocol (HTTP) adaptive streaming has been receiving attention to provide efficient video streaming services by adaptively adjusting the transmission rate. With increased demand for high-quality video streaming, since mobile devices are now equipped with multiple wireless interfaces connected to different networks (3G/4G or Wi-Fi), one possible solution to provide a better quality of experience (QoE) is to use multipath-based transmission schemes. In conventional HTTP adaptive streaming systems, the segment request policy initially operates in a buffering state and switches to a steady state once the playout buffer reaches a threshold. In the steady state, the client generates an ON/OFF traffic pattern that degrades bandwidth utilization and user QoE in multipath environments. In this paper, we propose a segment scheduling scheme for efficient bandwidth utilization in multipath environments. In our scheme, we first propose a collective segment request policy to improve bandwidth utilization and reducing the frequency of OFF periods. To improve network responsiveness, we present a method for adaptively adjusting the request interval. Subsequently, we propose a segment scheduler to prevent the out-of-order problem in multipath environments. Finally, a rate adaptation algorithm for the proposed request policy is proposed. Through simulation, we prove that our scheme significantly improves bandwidth utilization and increases the average bitrate.

Research of Message Scheduling for In-Vehicle FlexRay Network Static Segment Based on Next Fit Decreasing (NFD) Algorithm

FlexRay is becoming the in-vehicle communication network of the next generation. In this study, the main contents are the FlexRay network static segment scheduling algorithm and optimization strategy, improve the scheduling efficiency of vehicle network and optimize the performance of communication network. The FlexRay static segment characteristic was first analyzed, then selected bandwidth utilization as the performance metrics to scheduling problem. A signal packing method is proposed based on Next Fit Decreasing (NFD) algorithm. Then Frame ID (FID) multiplexing method was used to minimize the number of FIDs. Finally, experimental simulation by CANoe. FlexRay software, that shows the model can quickly obtain the message schedule of each node, effectively control the message payload size and reduced bus payload by 16.3%, the number of FID drops 53.8% while improving bandwidth utilization by 32.8%.

Segment Scheduling for Progressive Download-Based Multi-View Video Delivery under Successive View Switching

Segment Scheduling for Progressive Download-Based Multi-View Video Delivery under Successive View Switching

Using Two Independent Channels With Gateway for FlexRay Static Segment Scheduling

The FlexRay bus is a communication standard used in the automotive industry. It offers a deterministic message transmission in the static segment following a time-triggered schedule. Even if its bandwidth is ten times higher than the bandwidth of CAN, its throughput limits are going to be reached in high-class car models soon. A solution that could postpone this problem is to use an efficient scheduling algorithm that exploits both channels of the FlexRay. The significant and often neglected feature that can theoretically double the bandwidth is the possibility to use two independent communication channels that can intercommunicate through the gateway. In this paper, we propose a heuristic algorithm that decomposes the scheduling problem to the ECU-to-channel assignment subproblem which decides which channel the ECUs (Electronic Control Units) should be connected to and the channel scheduling subproblem which creates static segment communication schedules for both channels. The algorithm is able to create a schedule for cases where channels are configured in the independent mode as well as in the fault-tolerant mode or in cases where just part of the signals are fault-tolerant. Finally, the algorithm is evaluated on real data and synthesized data, and the relation between the portion of fault-tolerant signals and the number of allocated slots is presented.

HTTP 적응적 스트리밍을 위한 TCP 인지형 세그먼트 스케줄링 기법

HTTP Adaptive Streaming (HAS) is a technique that adapts its video quality to network conditions for providing Quality of Experience. In the HAS approach, a video content is encoded at multiple bitrates and the encoded video content is divided into several video segments. A HAS player estimates the network bandwidth and adjusts the video bitrate based on estimated bandwidth. However, the segment scheduler in the conventional HAS player requests video segments periodically without considering TCP. If the waiting duration for the next segment request is quite long, the TCP connection can be initialized and it restarts slow-start. Slow-start causes the reduction in TCP throughput and consequentially leads to low-quality video streaming. In this study, we propose a TCP-aware segment scheduling scheme to improve performance of HAS service. The proposed scheme adjusts request time for the next video request to prevent initialization of TCP connection and also considers the point of scheduling time. The simulation proves that our scheme improves the Quality of Service of the HAS service without buffer underflow issue.

끊김 없는 DASH 기반 라이브 스트리밍 서비스를 제공하기 위한 세그먼트 스케줄링 기법

Currently, several research studies are looking to improve the quality of DASH (Dynamic Adaptive Streaming over HTTP) based live streaming services. However, conventional DASH based streaming schemes cannot provide seamless playback while maintaining the low buffering and it adversely affects the QoE (Quality of Experience). To address this problem, we propose the QoE driven segment scheduling scheme. The proposed scheme adaptively schedules the segment request message according to the time and variation of segment fetching. Simulation results indicate that the proposed scheme improves the QoE of live streaming service by maintaining the low buffering delay and reducing the buffer underflow events.

Live birth after segmented intracytoplasmic sperm injection and pessary management for severe uterine prolapse

Segmentation of the assisted reproductive technology (ART) treatment not only assists patients with conception through the in vitro process but also, as in our case, with the motivation to manage a severe uterine prolapse. The patient was previously unsuccessful in the management of her severe uterine prolapse with a vaginal pessary and in conception with traditional in vitro fertilization treatment. Using segmented treatment pessary accustomization formed part of her treatment schedule and, therefore, added to the motivation to take control of her prolapse management. In addition, her prolapse management received clinical support for the duration of treatment. This is the first report on the successful use of segmented ART treatment and pessary support in a case of severe uterine prolapse. The segmented treatment schedule allowed the patient to progress from consultation to pregnancy test within a 3-month period.

ASDEX Upgrade Discharge Control System—A real-time plasma control framework

ASDEX Upgrade is a fusion experiment with a size and complexity to allow extrapolation of technical and physical conditions and requirements to devices like ITER and even beyond. In addressing advanced physics topics it makes extensive use of sophisticated real-time control methods. It comprises real-time diagnostic integration, dynamically adaptable multivariable feedback schemes, actuator management including load distribution schemes and a powerful monitoring and pulse supervision concept based on segment scheduling and exception handling. The Discharge Control System (DCS) supplies all this functionality on base of a modular software framework architecture designed for real-time operation. It provides system-wide services like workflow management, logging and archiving, self-monitoring and inter-process communication on Linux, VxWorks and Solaris operating systems. By default DCS supports distributed computing, and a communication layer allows multi-directional signal transfer and data-driven process synchronisation over shared memory as well as over a number of real-time networks. The entire system is built following the same common design concept combining a rich set of re-usable generic but highly customisable components with a configuration-driven component deployment method.We will give an overview on the architectural concepts as well as on the outstanding capabilities of DCS in the domains of inter-process communication, generic feedback control and pulse supervision. In each of these domains, DCS has contributed important ideas and methods to the on-going design of the ITER plasma control system. We will identify and describe these essential features and illustrate them with examples from ASDEX Upgrade operation.

Choices between segmented and unsegmented schedules and the self-control paradigm

A concurrent-chains procedure was used to examine choice between a segmented (two- or three-terminal-link segments schedules) and an unsegmented schedule (simple schedule) in terminal links with equal interreinforcement intervals. In most such experiments, preference for the unsegmented schedule has been found, but in a recent study with humans (Alessandri et al., 2010) a reversal in preference was found when, in the segmented schedule, the terminal link segmenting stimulus was presented briefly and closer to food delivery such that the early terminal link stimulus was temporally closer to the food delivery. In Experiment 1, an attempt to replicate this latter effect with pigeons was unsuccessful but this outcome was consistent with an account in terms of a self-control contingency involving conditioned reinforcers. According to this account, the unsegmented alternative consisted of an immediate, smaller presentation of a conditioned reinforcer (i.e., the impulsive, and thus usually the preferred, option in several experiments) and the segmented schedule led to a delayed, larger conditioned reinforcer (i.e., the self-control option). In Experiment 2, a reversal of preference toward the segmented schedule was found when a delay was added to both terminal links between the reinforced initial-link response and the onset of the corresponding terminal link stimulus. This result is consistent with a similar effect found with primary reinforcers in the self-control literature suggesting the utility of self-control as an account of preferences for unsegmented terminal links of concurrent chains schedules.

I-Swifter: Improving chunked network coding for peer-to-peer content distribution

Network coding has been proposed as a promising approach for peer-to-peer content distribution in recent literature. Not only reducing the average download time, but also improving resilience to peer churn has been showed as the benefits brought by network coding. State-of-the-art network coding content distribution systems perform network coding within segments or chunks, in order to reduce computational overhead. In our previous work (Xu et al. 2008), we proposed to schedule segment requests at a local-rarest-first basic. Local-rarest-first segment scheduling, as we demonstrated, is superior to the random scheduling. In this paper, we make a further step towards improving chunked network coding content distribution systems. We propose a requests reducer that reduces the overhead in control traffic and an encoding vectors reducer that eliminates the transmission of encoding vectors. Our contributions are to save unnecessary requests from downstream peers, and to reduce encoding vectors payload when the upstream peer owns the complete requested segment. This paper presents a realistic implementation, named I-Swifter. And we also make a comparative study on various related implementations. Experimental results show that there is about 10–20% of encoding vectors can be saved in I-Swifter. Moreover, I-Swifter improves average and maximum download time, the server load as well.

Psychological distance to reward: Effects of S+ duration and the delay reduction it signals

A concurrent-chains procedure was used to examine choice between segmented (two-component chained schedules) and unsegmented schedules (simple schedules) in terminal links with equal inter-reinforcement intervals. Previous studies using this kind of experimental procedure showed preference for unsegmented schedules for both pigeons and humans. In this study, two changes in the experimental procedure were made relative to the usual experimental procedure reported in the literature. The first was that in the segmented schedule the second terminal-link stimulus appeared close to reinforcement presentation and the second was that the change in stimulus was brief, allowing the first stimulus to reappear and to be contiguous with reinforcement. With these changes, preference occurred for the segmented schedule. This result is consistent with principles of conditioned reinforcement, including delay-reduction theory.

Preference for a segmented schedule using a brief S+ stimulus correlated with a great delay reduction in humans

Past studies using the concurrent-chain procedure showed that pigeons and humans generally prefer an unsegmented schedule to a segmented schedule. This finding is ostensibly inconsistent with theories of conditioned reinforcement such as delay-reduction theory. In the present study with humans, two changes in the basic segmented schedule were implemented to resolve this inconsistency. The first change was that in the segmented schedule the terminal-link stimulus (S+ stimulus) changed late in the terminal-link, close to reinforcement presentation. The second change was that the presentation of the segmenting stimulus, S+, was brief allowing a reinstatement of the early terminal-link stimulus, which is contiguous with reinforcement. Our data constitute the first demonstration of preference for the segmented schedule when a brief S+ is correlated with a greater reduction in delay to reinforcement.

Achieving multi-class service differentiation in WDM optical burst switching networks: a probabilistic preemptive burst segmentation scheme

We propose a Probabilistic Preemptive Burst Segmentation (PPBS) scheduling scheme to provide priority classes with different Quality-of-service (QoS) requirements in WDM Optical Burst Switching (OBS) networks. The PPBS scheme enables high priority bursts to preempt and segment low priority bursts in a probabilistic fashion. The PPBS scheme achieves 100% isolation among priority classes, and burst loss probabilities can be controlled by tunable parameters. Our PPBS queueing model also implicitly enables us to obtain several results related to the Erlang's loss function which may be useful in the role of this function arising in some areas of queueing theory, as well as characterizing a loss rate region that work conserving burst scheduling techniques can achieve. As an application to providing service differentiation, we show how the PPBS scheme can minimize the total sum of loss rates and achieve proportional loss differentiation. Finally, we also demonstrate the effectiveness of the PPBS scheme empirically using realistic Internet traffic model, e.g., long range dependent traffic model.

Psychological distance to reward in monkeys

A concurrent-chains schedule was employed to examine crab-eating macaques' choice between segmented and unsegmented fixed-interval 30-s schedules. A stimulus change occurred during one of the fixed-interval schedules (segmented schedule), while no stimulus change occurred during the other (unsegmented schedule). The subjects were exposed to three consecutive stimulus-change conditions, in an attempt to explore whether correlation of the stimulus changes with a fixed interval of nonreinforcement affects the preference between the alternatives. When the stimulus change always occurred at a half point of the segmented schedule (the first and third conditions), all subjects preferred the fixed-interval schedule without stimulus changes. This replicated previous findings with pigeons and humans. On the other hand, when the intervals before and after the stimulus change varied on every entry to the segmented schedule with the sum of them being constant (the second condition), the subjects were indifferent to the alternatives. These results are consistent with the view that the preference for unsegmented schedules over segmented ones might be due to aversiveness which the initial component in the segmented schedule possesses as a result of its correlation with a fixed interval of nonreinforcement.

PSYCHOLOGICAL DISTANCE TO REWARD: SEGMENTATION OF APERIODIC SCHEDULES OF REINFORCEMENT

College students responded for monetary rewards in two experiments on choice between differentially segmented aperiodic schedules of reinforcement. On a microcomputer, the concurrent chains were simulated as an air-defense video game in which subjects used two radars for detecting and destroying enemy aircraft. To earn more cash-exchangeable points, subjects had to shoot down as many planes as possible within a given period of time. For both experiments, access to one of two radar systems (terminal link) was controlled by a pair of independent concurrent variable-interval 60-s schedules (initial link) with a 4-s changeover delay always in effect. In Experiment 1, the appearance of an enemy aircraft in the terminal link was determined by a variable-interval (15 s or 60 s) schedule or a two-component chained variable-interval schedule of equal duration. Experiment 2 was similar to Experiment 1 except for the segmented schedule, which had three components. Subjects preferred the unsegmented schedule over its segmented counterpart in the conditions with variable-interval 60 s, and preference tended to be more pronounced with more components in the segmented schedule. These findings are compatible with those from previous studies of periodic and aperiodic schedules with pigeons or humans as subjects.

PSYCHOLOGICAL DISTANCE TO REWARD: A HUMAN REPLICATION

Choice behavior in college students was examined in two experiments using the concurrent-chains procedure. In both experiments, the concurrent chains were presented on a microcomputer in the form of an air-defense game in which subjects used two radar systems to detect and subsequently destroy enemy aircraft. Access to one of two radar systems was controlled by a pair of independent concurrent variable-interval 60-s schedules with a 4-s changeover delay always in effect. In the terminal link, the appearance of an enemy aircraft was determined by a pair of differentially segmented fixed-time schedules (Experiment 1) or fixed-interval schedules (Experiment 2) of equal overall duration. In Experiment 1, the terminal-link duration was either 20 s or 40 s, and subjects preferred the unsegmented to the segmented intervals. In Experiment 2, the duration was either 10 s or 60 s, and the reinforcement contingencies required responding during the terminal link. Prior to the reinstatement of the initial link, subjects estimated the duration of the terminal-link schedule. Segmentation affected choice in the 60-s conditions but not in the 10-s ones. Preference for the unsegmented schedule was correlated with an overestimation of the durations for the segmented schedules. These results replicated those found in animal experiments and support the notion of increasing the psychological distance to reward by segmenting a time-based schedule of reinforcement.

Robotic work station for microscale synthetic chemistry: On-line absorption spectroscopy, quantitative automated thin-layer chromatography, and multiple reactions in parallel

A robotic work station has been constructed for automatically initiating and monitoring microscale chemical reactions. The work station consists of a robot with a general-purpose arm and interchangeable special-purpose hands, a carousel of seven reaction vessels, a series of stations for performing quantitative automated thin-layer chromatography (TLC), an on-line multichannel absorption spectrophotometer, sensors for verification, syringes and pumps for sample and solvent delivery, a supervisory computer for real-time data acquisition and process control, and a graphics terminal for data display. The controlling software is menu-driven and contains a scheduling algorithm that permits multiple reactions to be performed simultaneously. The automated TLC process is performed in four stages (plate dispensing, sample application, plate development, and plate densitometry), and samples are moved sequentially among these stations by the robot. The partial autonomy of these separate stations permits distributed sample processing. Four TLC plates are processed simultaneously with interleaving segmented schedules, giving a 160% increase in TLC sample throughput. The workstation can be applied to yield optimizations of synthetic reactions and to the exploration of synthetic reaction spaces. The capabilities of the workstation are demonstrated in the two-step synthesis of tetraphenylporphyrin from benzaldehyde and pyrrole in 1 h at room temperature. Kinetic data are obtained from a single-batch reaction concerning the consumption of benzaldehyde, the side reactions forming dipyrrylmethenes, and the formation of tetraphenylporphyrin.

PREFERENCE FOR SIMPLE INTERVAL SCHEDULES OF REINFORCEMENT IN CONCURRENT CHAINS: EFFECTS OF SEGMENTATION RATIO

A concurrent-chains procedure was used to examine pigeons' preferences between segmented and unsegmented terminal-link schedules of reinforcement. During the initial link, a pair of independent, concurrent variable-interval 60-s schedules was in effect. In the terminal link, reinforcement was provided by a chain fixed-interval fixed-interval schedule on one key and by a simple fixed-interval schedule with an equal interreinforcement interval in the other. The relative duration between the first and second components (segmentation ratio) in the terminal-link chained schedule was systematically varied while the terminal-link duration was kept constant at either 15 s or 30 s in two sets of conditions. With few exceptions, the simple schedule was preferred to the chained schedule. Furthermore, this preference was inversely related to the size of the segmentation ratio in the segmented schedule. When the segmentation ratio was smaller than 1:1, preference was more extreme for a 30-s condition than for a 15-s condition. However, preference decreased more rapidly in conditions with the longer terminal-link duration when the ratio increased. Taken together, these results were consistent with previous findings concerning the effect of the terminal-link duration on choice between segmented and unsegmented schedules. In addition, the data suggested that segmentation ratio in a segmented schedule constitutes another potent factor influencing preference for the unsegmented schedule.