scholarly journals Performance Evaluation of Priority Load-Aware Scheduling (PLAS) Algorithm for IEEE802.16 Networks

2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Abdulhakeem Abdulazeez ◽  
Solomon Orduen Yese ◽  
Aminu Mohammed
Keyword(s):  
Service Providers ◽  
Scheduling Algorithm ◽  
Discrete Event ◽  
Area Network ◽  
Average Delay ◽  
Queuing Delay ◽  
Metropolitan Area Network ◽  
Event Simulation ◽  
Wireless Broadband ◽  
Improved Performance

In recent years, there has been an increase in the transmission of multimedia services due to the emergence of wireless broadband (WiBB) technologies such as WiMAX. WiMAX supports multiple QoS classes for transmission of different multimedia applications. However, satisfying the requirements of these applications with the often-limited resources has been a major challenge, which requires an efficient scheduling scheme such as PLAS. PLAS is a variant of LAWRR designed to reduce queuing delay of real-time traffics in WiBB networks. Several simulation experiments were conducted to evaluate the performance of PLAS against the LAWRR algorithm. The results revealed that PLAS outperforms the other scheme in terms of average delay for low input traffic. However, the metric (delay) used and the traffics generated for the simulation are not adequate to realistically evaluate the performance of a scheduling algorithm in a typical metropolitan area network. In this study, we further evaluated the performance of PLAS and LAWRR under varying higher input traffics, and an additional performance metric, using discrete event simulation. The results demonstrated that the PLAS achieved better results in terms of queuing delay and throughput compared to LAWRR. The improved performance will lead to better user experience, which will increase the number of subscribers and consequently increase revenue for service providers.

ECSIM: DISCRETE EVENT SIMULATION USING EVENT CALCULUS

1995 ◽  
Vol 04 (01n02) ◽  
pp. 135-156
Author(s):  
LODE R. MISSIAEN
Keyword(s):  
Discrete Event Simulation ◽  
Intelligent Agents ◽  
Scheduling Algorithm ◽  
Inductive Learning ◽  
Discrete Event ◽  
Event Calculus ◽  
Event Simulation ◽  
Classical Simulation ◽  
History Of ◽  
Planning Decision

This paper presents the theory and implementation of a logic based discrete event simulation system ECSIM, Event Calculus SIMulation. ECSIM’s representation language is PROLOG extended with temporal predicates derived from the event calculus. The theory defines the truth value of a property given a history of events. ECSIM can represent actions that happen at a particular point in time, and activities that happen over a period of time; it can represent properties that change discretely and continuously over time. ECSIM’s scheduling algorithm uses activity scanning to generate event notices for all future activities. ECSIM’s major distinction with other simulation systems is its reference to the complete history of simulated time. A given event schedule can be analyzed by deriving the properties of the world at any time in the simulated history. ECSIM’s logic programming framework enables classical simulation to be extended with explanation generation, inductive learning, planning, decision support, simulation of intelligent agents, and symbolic simulation.

A Node-Oriented Discrete Event Scheduling Algorithm Based on Finite Resource Model

2019 ◽  
Vol 31 (3) ◽  
pp. 67-82
Author(s):  
Yu Huang ◽  
Wanxing Sheng ◽  
Peipei Jin ◽  
Baicuan Nie ◽  
Meikang Qiu ◽  
...  
Keyword(s):  
Discrete Event Simulation ◽  
Packet Loss ◽  
Large Scale ◽  
Network Simulation ◽  
Scheduling Algorithm ◽  
Discrete Event ◽  
Event Simulation ◽  
Resource Limited ◽  
Event Scheduling ◽  
Low Performance

Discrete event simulation is the most important and essential part in network simulation. The node-oriented model of discrete event scheduling is a model that allocates computing resources as nodes and makes the discrete event simulation as a simulation task on nodes. In this article the reason of low performance in large-scale network simulation is analyzed, and an ideal node-oriented model of discrete event scheduling is presented and a resource-limited node-oriented model of discrete event scheduling by adding some restrictions on network resources is proposed. Then, the authors complete contrast experiments of the resource-limited node-oriented model of discrete event scheduling and NS2. Finally, packet loss in resource-limited node-oriented model of discrete event scheduling is examined. Also, NS2 is discussed in this article and the authors have proposed an improved method for the packet loss algorithm in a resource-limited node-oriented model of discrete event scheduling.

The Design and Implementation of Business Models in Metropolitan Broadband Networks

2011 ◽  
pp. 196-210 ◽  
Author(s):  
Antonios Alexiou ◽  
Christos Bouras ◽  
John Primpas ◽  
Dimitrios Papagiannopoulos
Keyword(s):  
Business Models ◽  
Service Providers ◽  
Access Network ◽  
Wireless Systems ◽  
Cost Effective ◽  
Area Network ◽  
Broadband Networks ◽  
Metropolitan Area Network ◽  
The Public ◽  
The City

This chapter presents the design principles that cover the implementation of broadband infrastructure in the region of Western Greece, by examining all the necessary parameters that arise while implementing such a critical developmental project. The broadband infrastructure that is deployed is either based on optical fiber (on big municipalities) or on wireless systems (OFDM based and WiFi cells). Furthermore, we present as two case studies all issues of the designing of the Metropolitan Area Network of Patras, the third largest city of Greece and the Wireless Access Network of Messatida. The major target of the broadband networks is to interconnect the buildings of the public sector in the city and also deploy infrastructure (fibers or wireless systems) that will create conditions of competition in providing both access and content services to the advantage of the end consumer. The usage of the broadband infrastructure by service providers will be based on the open availability of the infrastructure in a cost-effective way. Finally, we present the main characteristics of a proposed business plan that ensures financial viability of the broadband infrastructure and guarantees the administration, growth, and exploitation of infrastructure.

scholarly journals A Comprehensive TCO Evaluation Method for Electric Bus Systems Based on Discrete-Event Simulation Including Bus Scheduling and Charging Infrastructure Optimisation

2020 ◽  
Author(s):  
Dominic Jefferies ◽  
Dietmar Göhlich
Keyword(s):  
Discrete Event Simulation ◽  
Evaluation Method ◽  
Scheduling Algorithm ◽  
Discrete Event ◽  
Local Conditions ◽  
Charging Infrastructure ◽  
Event Simulation ◽  
Electric Bus ◽  
Bus Network ◽  
Bus Networks

Bus operators around the world are facing the transformation of their fleets from fossil-fuelled to electric buses. Two technologies prevail: Depot charging and opportunity charging at terminal stops. Total cost of ownership (TCO) is an important metric for the decision between the two technologies, however, most TCO studies for electric bus systems rely on generalised route data and simplifying assumptions that may not reflect local conditions. In particular, the need to re-schedule vehicle operations to satisfy electric buses’ range and charging time constraints is commonly disregarded. We present a simulation tool based on discrete-event simulation to determine the vehicle, charging infrastructure, energy and staff demand required to electrify real-world bus networks. These results are then passed to a TCO model. A greedy scheduling algorithm is developed to plan vehicle schedules suitable for electric buses. Scheduling and simulation are coupled with a genetic algorithm to determine cost-optimised charging locations for opportunity charging. A case study is carried out in which we analyse the electrification of a metropolitan bus network consisting of 39 lines with 4748 passenger trips per day. The results generally favour opportunity charging over depot charging in terms of TCO, however, under some circumstances, the technologies are on par. This emphasises the need for detailed analysis of the local bus network in order to make an informed procurement decision.

scholarly journals Desain Antena Wi-Fi Dengan Media Seng

2012 ◽  
Vol 4 (2) ◽  
pp. 18
Author(s):  
Eka Wahyudi ◽  
Adnan Purwanto ◽  
Teguh Iklas
Keyword(s):  
Ieee 802.11 ◽  
Metropolitan Area ◽  
Wireless Local Area Network ◽  
Service Providers ◽  
Local Area Network ◽  
Local Area ◽  
Area Network ◽  
Internet Service ◽  
Metropolitan Area Network ◽  
Link Budget

Teknologi Internet berbasis Wi-Fi dibuat dan dikembangkan di Amerika Serikat yaitu oleh Institute of Electrical and Electronis Engineers (IEEE) yang berdasarkan kelompok standar teknis perangkat bernomor IEEE 802.11. Perangkat Wi-Fi sebenarnya tidak hanya mampu bekerja di jaringan Wireless Local Area Network (WLAN), tetapi juga di jaringan Wireless Metropolitan Area Network (WMAN). Kuantitas pengguna Internet berbasis teknologi Wi-Fi yang semakin meningkat di berbagai belahan dunia, telah mendorong internet service providers (ISP) untuk membangun hotspot yang di berbagai kota-kota besar. Hotspot merupakan suatu tempat dimana tersedianya koneksi jaringan di mana para pemakai dapat melakukan akses Internet dengan cara nirkabel (wireless) tanpa tergantung kepada jaringan fisik. Jangkauan hotspot  dapat dimaksimalkan dengan memanfaatkan antena dengan desain khusus sehingga cakupan (coverage) pancaran sinyal lebih luas. Proses pembuatan desain antena dengan media seng yang diaplikasikan untuk hotspot Wi-Fi pada outdoor diawali dengan perhitungan link budget, antara lain gain dan beamwidth dari antena. Proses pengukuran sinyal diukur dengan menggunakan bantuan software NetStumbler.

scholarly journals Performance modelling of multi-tier cloud applications using Simpy

2021 ◽  
Author(s):  
Dayle Chettiar
Keyword(s):  
Response Time ◽  
Discrete Event Simulation ◽  
Service Providers ◽  
Discrete Event ◽  
Queueing Network ◽  
Analytical Models ◽  
Performance Modelling ◽  
Event Simulation ◽  
Application Service ◽  
The Mean

Todays cloud deployed applications are mostly multi-tiered. Usually, the first tier consists of an Application Service Providers' (ASPs) web servers, the second tier has application servers and the third tier contains database servers. Tiered architectures are often difficult to evaluate in terms of performance. Existing performance models are very effective in finding the mean performance measures. However, metrics such as response-time percentiles are of greater importance to the end-users since it is more desirable to reduce the variability of a system’s response time, rather than minimizing the mean response time. In this work, a multi-tier application is modeled as an open queuing network of 3-tiers and the response-time percentiles are estimated using discrete event simulation. Here, we assume that each tier is replicated into a number of copies and each copy runs on a separate Virtual Machine (VM). Although simulation models are computationally more expensive as compared to analytical models, they are much more general. The simulation model of this work can be used as decision support for ASPs in order to determine the optimal configuration of VMs for a given workload such that a required response-time percentile is within a given threshold. In this work, Simpy, a discrete event simulation framework, has been used. The results show that as the number of VMs are increased in a 3-tier open queueing network, the overall system performance (i.e. percentiles and mean response times) does not necessarily become better. The results further show that different system configurations containing the same number of VMs, yield different performance depending on the replication level in different tiers.

scholarly journals A Comprehensive TCO Evaluation Method for Electric Bus Systems Based on Discrete-Event Simulation Including Bus Scheduling and Charging Infrastructure Optimisation

2020 ◽  
Vol 11 (3) ◽  
pp. 56
Author(s):  
Dominic Jefferies ◽  
Dietmar Göhlich
Keyword(s):  
Discrete Event Simulation ◽  
Evaluation Method ◽  
Scheduling Algorithm ◽  
Discrete Event ◽  
Local Conditions ◽  
Charging Infrastructure ◽  
Event Simulation ◽  
Electric Bus ◽  
Bus Network ◽  
Bus Networks

Bus operators around the world are facing the transformation of their fleets from fossil-fuelled to electric buses. Two technologies prevail: Depot charging and opportunity charging at terminal stops. Total cost of ownership (TCO) is an important metric for the decision between the two technologies; however, most TCO studies for electric bus systems rely on generalised route data and simplifying assumptions that may not reflect local conditions. In particular, the need to reschedule vehicle operations to satisfy electric buses’ range and charging time constraints is commonly disregarded. We present a simulation tool based on discrete-event simulation to determine the vehicle, charging infrastructure, energy and staff demand required to electrify real-world bus networks. These results are then passed to a TCO model. A greedy scheduling algorithm is developed to plan vehicle schedules suitable for electric buses. Scheduling and simulation are coupled with a genetic algorithm to determine cost-optimised charging locations for opportunity charging. A case study is carried out in which we analyse the electrification of a metropolitan bus network consisting of 39 lines with 4748 passenger trips per day. The results generally favour opportunity charging over depot charging in terms of TCO; however, under some circumstances, the technologies are on par. This emphasises the need for a detailed analysis of the local bus network in order to make an informed procurement decision.

scholarly journals An online short-term bed occupancy rate prediction procedure based on discrete event simulation

2014 ◽  
Vol 3 (4) ◽  
pp. 37 ◽  
Author(s):  
Zhu Zhecheng
Keyword(s):  
Health Service ◽  
Discrete Event Simulation ◽  
Service Providers ◽  
Discrete Event ◽  
Occupancy Rate ◽  
Bed Occupancy ◽  
Short Term ◽  
Hospital System ◽  
Event Simulation ◽  
Health Service Providers

In recent years, population growth and aging society impose large pressure on the resource requirement in Singapore public hospital system. Beds are one of the most critical resources in healthcare system. How to manage beds efficiently is an important and challenging task for the health service providers in any healthcare systems. One frequently used performance indicator of bed management is bed occupancy rate, which measures the bed utilization. In this paper, an online prediction procedure based on discrete event simulation is proposed and developed to predict bed occupancy rate in a short term period. Simulation results show that the predicted values are closer to the actual values with narrower confidence interval compared to the offline approach. Hence such a prediction procedure is able to provide a more reliable reference for decision making of the health service providers.

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