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Search Results: 1 - 10 of 2226 matches for " Scheduling "
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Structural Properties of Optimal Scheduling Policies for Wireless Data Transmission  [PDF]
Nomesh Bolia, Vidyadhar Kulkarni
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.510069
Abstract: We analyze a cell with a fixed number of users in a time period network. The base station schedules to serve at most one user in a given time period based on information about the available data rates and other parameter(s) for all the users in the cell. We consider infinitely backlogged queues and model the system as a Markov Decision Process (MDP) and prove the monotonicity of the optimal policy with respect to the \"starvation age\" and the available data rate. For this, we consider both the discounted as well as the long-run average criterion. The proofs of the monotonicity properties serve as good illustrations of analyzing MDPs with respect to their optimal solutions.
A Heuristic Approach for Assembly Scheduling and Transportation Problems with Parallel Machines  [PDF]
Peng-Sheng You, Yi-Chih Hsieh, Ta-Cheng Chen, Yung-Cheng Lee
iBusiness (IB) , 2013, DOI: 10.4236/ib.2013.51B006
Abstract: Many firms have to deal with the problems of scheduling and transportation allocation. The problems of assembly scheduling mainly focus on how to arrange orders in proper sequence on the assembly line with the purpose of minimizing the maximum completion time before they are flown to their destinations. Transportation allocation problems arise in how to assign processed orders to transport modes in order to minimize penalties such as earliness and tardiness. The two problems are usually separately discussed due to their complexity. This paper simultaneously deals with these two problems for firms with multiple identical parallel machines. We formulate this problem as a mixed integer programming model. The problem belongs to the class of NP-complete combinatorial optimization problems. This paper develops a hybrid genetic algorithm to obtain a compromised solution within a reasonable CPU time. We evaluate the performance of the presented heuristic with the well-known GAMS/CPLEX software. The presented approach is shown to perform well compared with well-known commercial software.
Remote Scheduling System for Drip Irrigation System Using Geographic Information System  [PDF]
Kadeghe G. Fue, Camilius Sanga
Journal of Geographic Information System (JGIS) , 2015, DOI: 10.4236/jgis.2015.75044
Abstract: The Internet is widely accessible in Tanzania. Most of the technologies used in different organizations have changed to address their functions using web based information systems. In this paper, attempt is made to design software system using geographical information system (GIS) for the spatial and temporal distribution of irrigation supply for large-scale drip irrigation systems in Tanzania. Map based information system has gained popularity after evolution of simple tools to present spatial information using Internet. Due to water scarcity, it is envisioned that by 2050 the world won’t have enough water for communities, industries and agriculture. Web based precision irrigation system refers to deployment of remotely precision irrigation services using the application interface that connects to the Internet. Hence, this study presents the GIS in the context of precision farming to achieve precision irrigation strategy with special reference to precision farming of tea in Tanzania. The GIS-based irrigation scheduling system was designed for the scheduling daily drip irrigation water deliveries and regular monitoring of irrigation delivery performance for maximum yield. The “Scheduling” program computes the right amount of irrigation deliveries based on tea water requirements. The “Monitoring” program gives information on the uniformity of water distribution and the shortfall or excess.
Quantitative Approaches on Staff Scheduling and Rostering in Hospitality Management: An Overview  [PDF]
Marta Rocha, Jose F. Oliveira, Maria Antonia Carravilla
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.21016
Abstract: Staff scheduling and rostering problems, with application in several application areas, from transportation systems to hospitals, have been widely addressed by researchers. This is not the case of hospitality services, which have been forgotten by the quantitative research literature. The purpose of this paper is to provide some insights on the application of staff scheduling and rostering problems to hospitality management operations, reviewing existing approaches developed in other similar areas, such as nurse rostering or examining adaptable problem models, such as the tour scheduling.
Design of Software for Maintenance Workforce Scheduling (A Case Study of Afam Power Station, Nigeria)  [PDF]
Ikuobase Emovon, Macaulay Thomas Lilly, Stephen Ogajiye Tamuno-Ojuemi Ogaji
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.45031
Abstract: This paper is concerned with the optimization of the workforce scheduling for solving maintenance problems. To achieve this aim an optimsation software for (5, 7) problem was developed. The programme was written in Quick Basic. The software was designed to produce a seven day schedule for organization operating a seven day week. Hence organization operating a five day schedule wishing to change to a seven day schedule we find this software very useful. The Quick-Basic computer programme was based on Alfares [1, 2] algorithm for solving (5,7) schedule problem. Data collected from Afam power station, Nigeria was used as input data. The test result shows the software is capable of determining workforce size and assigning workers to day-off pattern. The seven-day schedule produced savings of 11% maintenance labour cost when compared with the 5-day schedule currently being practiced by the Power station [3].
Enhanced Uplink Scheduling for Continuous Connectivity in High Speed Packet Access Systems  [PDF]
Saied M. Abd El-Atty, Konstantinos Lizos
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.58055
Abstract: The efficiency of high speed packet access (HSPA) systems is mainly based on channel quality information (CQI) reports transmitted by user equipment (UE) to Node B. In this paper, we propose an improved CQI prediction scheme based on a finite state Markov chain (FSMC) model for wireless channel, in order to reduce CQI signaling overhead in the HSPA system. Then, we introduce an enhanced uplink packet scheduling (EUPS) scheme to provide quality of services (QoS) guaranteed for continuous packet connectivity in the enhanced uplink (EUL). EUPS serves the active UEs not only according to buffer status but also according to reported state of the wireless channel of each UE. The performance of the proposed scheme in terms of average packet delay, average packet drop and average cell throughput is compared to the classical scheduler of 3GPP standards. The simulation results show the effectiveness of the proposed scheme.
Dynamic Optimization of Caregiver Schedules Based on Vital Sign Streams  [PDF]
Mohamed Saad, Bilal Khan
E-Health Telecommunication Systems and Networks (ETSN) , 2013, DOI: 10.4236/etsn.2013.22006

Hospital facilities use a collection of heterogeneous devices, produced by many different vendors, to monitor the state of patient vital signs. The limited interoperability of current devices makes it difficult to synthesize multivariate monitoring data into a unified array of real-time information regarding the patients state. Without an infrastructure for the integrated evaluation, display, and storage of vital sign data, one cannot adequately ensure that the assignment of caregivers to patients reflects the relative urgency of patient needs. This is an especially serious issue in critical care units (CCUs). We present a formal mathematical model of an operational critical care unit, together with metrics for evaluating the systematic impact of caregiver scheduling decisions on patient care. The model is rich enough to capture the essential features of device and patient diversity, and so enables us to test the hypothesis that integration of vital sign data could realistically yield a significant positive impact on the efficacy of critical care delivery outcome. To test the hypothesis, we employ the model within a computer simulation. The simulation enables us to compare the current scheduling processes in widespread use within CCUs, against a new scheduling algorithm that makes use of an integrated array of patient information collected by an (anticipated) vital sign data integration infrastructure. The simulation study provides clear evidence that such an infrastructure reduces risk to patients and lowers operational costs, and in so doing reveals the inherent costs of medical device non-interoperability.

Effective Task Scheduling for Embedded Systems Using Iterative Cluster Slack Optimization  [PDF]
Jongdae Kim, Sungchul Lee, Hyunchul Shin
Circuits and Systems (CS) , 2013, DOI: 10.4236/cs.2013.48063

To solve computationally expensive problems, multiple processor SoCs (MPSoCs) are frequently used. Mapping of applications to MPSoC architectures and scheduling of tasks are key problems in system level design of embedded systems. In this paper, a cluster slack optimization algorithm is described, in which the tasks in a cluster are simultaneously mapped and scheduled for heterogeneous MPSoC architectures. In our approach, the tasks are iteratively clustered and each cluster is optimized by using the branch and bound technique to capitalize on slack distribution. The proposed static task mapping and scheduling method is applied to pipelined data stream processing as well as for batch processing. In pipelined processing, the tradeoff between throughput and memory cost can be exploited by adjusting a weighting parameter. Furthermore, an energy-aware task mapping and scheduling algorithm based on our cluster slack optimization is developed. Experimental results show improvement in latency, throughput and energy.

Energy Efficient and QoS Aware Framework for Video Transmission over Wireless Sensor Networks  [PDF]
Mohammed Ezz El Dien, Aliaa A. A. Youssif, Atef Zaki Ghalwash
Wireless Sensor Network (WSN) , 2016, DOI: 10.4236/wsn.2016.83003
Abstract: Wireless Multimedia Sensor Networks (WMSNs), is a network of sensors, which are limited in terms of memory, computing, bandwidth, and battery lifetime. Multimedia transmission over WSN requires certain QoS guarantees such as huge amount of bandwidth, strict delay and lower loss ratio that makes transmitting multimedia is a complicated task. However, adopting cross-layer approach in WMSNs improves quality of service of WSN under different environmental conditions. In this work, an energy efficient and QoS aware framework for transmitting multimedia content over WSN (EQWSN) is presented, where packet, queue and path scheduling were introduced. It adapts the application layer parameter of video encoder to current wireless channel state, and drops less important packets in case of network congestion according to packet type. Finally, the path scheduling differentiates packets types/priority and route them through different paths with different QoS considering network lifetime. Simulation results show that the new scheme EQWSN transmits video quality with QoS guarantees in addition to prolonging network lifetime.
Chronically Evaluated Highest Instantaneous Priority Next: A Novel Algorithm for Processor Scheduling  [PDF]
Amit Pandey, Pawan Singh, Nirayo H. Gebreegziabher, Abdella Kemal
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.44013
Abstract: This paper proposes a novel chronically evaluated highest instantaneous priority next processor scheduling algorithm. The currently existing algorithms like first come first serve, shortest job first, round-robin, shortest remaining time first, highest response ratio next and varying response ratio priority algorithm have some problems associated with them. Some of them can lead to endless waiting or starvation and some of them like round-robin has problem of too many context switches and high waiting time associated with them. In the proposed algorithm, we have taken care of all such problems. As the novel algorithm is capable of achieving as good results as shortest remaining time first algorithm and also it will never lead to starvation.
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