Deadline Monotonic Policy over 802.11 Throughput and Average Service Time

AbstractRecently, the number of Internet of Things (IoT) devices connected to the Internet has increased dramatically as well as the data produced by these devices. This would require offloading IoT tasks to release heavy computation and storage to the resource-rich nodes such as Edge Computing and Cloud Computing. Although Edge Computing is a promising enabler for latency-sensitive related issues, its deployment produces new challenges. Besides, different service architectures and offloading strategies have a different impact on the service time performance of IoT applications. Therefore, this paper presents a novel approach for task offloading in an Edge-Cloud system in order to minimize the overall service time for latency-sensitive applications. This approach adopts fuzzy logic algorithms, considering application characteristics (e.g., CPU demand, network demand and delay sensitivity) as well as resource utilization and resource heterogeneity. A number of simulation experiments are conducted to evaluate the proposed approach with other related approaches, where it was found to improve the overall service time for latency-sensitive applications and utilize the edge-cloud resources effectively. Also, the results show that different offloading decisions within the Edge-Cloud system can lead to various service time due to the computational resources and communications types.

Download Full-text

Observations and Models for Red Giants with Unusual Dust

International Astronomical Union Colloquium ◽

10.1017/s0252921100063259 ◽

1989 ◽

Vol 106 ◽

pp. 367-367

Author(s):

Ian Griffin ◽

C.J. Skinner ◽

B.R. Whitmore

Keyword(s):

Service Time ◽

Dust Emission ◽

Red Giants ◽

Carbon Stars ◽

Near Ir ◽

Medium Resolution ◽

Silicate Feature ◽

L Band ◽

M Stars ◽

Selection Of

We present near IR (H, K and L band) medium resolution (ƛ/Δƛ ∼ 600) spectra for a selection of 9 red giants which have previously been shown to exhibit anomalous dust emission as characterised by their IRAS LRS spectra. The objects observed (during UKIRT and AAT service time) include Carbon stars whose LRS spectra show the 9.7μm silicate feature and also M stars whose LRS spectra display an 11.3μm feature similar to that usually associated with emission from SiC dust grains.

Download Full-text

Reliability Analysis of Jack-Up Platforms Based on Fatigue Degradation

21st International Conference on Offshore Mechanics and Arctic Engineering, Volume 2 ◽

10.1115/omae2002-28360 ◽

2002 ◽

Cited By ~ 3

Author(s):

Naser Shabakhty ◽

Pieter van Gelder ◽

Hotze Boonstra

Keyword(s):

Service Time ◽

Great Part ◽

Fatigue Reliability ◽

Original Design ◽

Operational Conditions ◽

Stress Fluctuation ◽

The Difference ◽

Offshore Industry ◽

Jack Up ◽

Load Conditions

Generally, jack-up structures are used for production drilling and exploration of hydrocarbons. The combination of mobility and the behavior as a fixed structure in operational conditions has made it an important structure in the offshore industry over the last 40 years. When a jack-up structure has been in operation for a great part of its original design-life and intention is there to extend the usage of this structure at a specific location, an investigation on fatigue degradation of the structure is an essential factor that has to be carried out before taking any decision. Fatigue is the process of damage accumulation in material due to stress fluctuation caused by variation of loads in service time. The fatigue failure occurs when accumulated damage has exceeded a critical level. In this paper, the remaining fatigue capacity of the jack-up structure is considered as an indicator for adequate use of the structure. It can be specified based on the difference between design-fatigue and fatigue experienced by the structure. The design-fatigue can be determined based on fluctuation of loads during the lifetime of the structure and experienced fatigue is specified by the load conditions, which the structure has experienced during its service time. When the information on the load conditions which the structure has experienced in its service time is available or known precisely, determination of the remaining fatigue capacity could be carried out by using the Palmgren–Miner’s rule. In practice, uncertainties are present in loads and characteristics of material. Hence it will be reasonable to determine the remaining fatigue reliability of the structure by the reliability methods. In this paper, based on a crack propagation approach and achieved information from inspection, it is shown that the remaining fatigue reliability of jack-up structures could be determined and updated by using a Bayesian procedure in the duration of the service time.

Download Full-text

A Review of Sufficient Schedulability Analysis for Fixed Priority Scheduling Systems

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.741.856 ◽

2015 ◽

Vol 741 ◽

pp. 856-859

Author(s):

Yan Feng Zhai ◽

Feng Xiang Zhang

Keyword(s):

Schedulability Analysis ◽

Priority Assignment ◽

Priority Scheduling ◽

Fixed Priority ◽

Fixed Priority Scheduling ◽

Rate Monotonic ◽

Simple Implementation ◽

Deadline Monotonic ◽

Activation Rates

This papercarries out a survey of sufficient schedulability analysis forfixed priority (FP) scheduling. The most common used fixed priority assignment is the rate monotonic (RM) algorithm, according to its policy, the task priorities are ordered based on their activation rates, so that the task with the shortest period is assigned the highest priority. However, when each task’s relative deadline is not equal to its period, the RM algorithm is not suitable to assign the task priorities. When relative deadlines are less than or equal to periods,the deadline monotonic (DM) algorithm can be deployed to schedule the tasks. The utilization based schedulability analysis has the advantage of simple implementation, and manyexisting schedulability analyses on uniprocessor are covered.

Download Full-text

Stationary Poisson departure processes from non-stationary queues

Journal of Applied Probability ◽

10.2307/3214138 ◽

1986 ◽

Vol 23 (1) ◽

pp. 256-260 ◽

Cited By ~ 5

Author(s):

Robert D. Foley

Keyword(s):

Poisson Process ◽

Service Time ◽

Queueing Systems ◽

Arrival Rate ◽

Distribution Functions ◽

Arrival Process ◽

Service Time Distribution ◽

Departure Process ◽

Infinite Server ◽

Departure Processes

We present some non-stationary infinite-server queueing systems with stationary Poisson departure processes. In Foley (1982), it was shown that the departure process from the Mt/Gt/∞ queue was a Poisson process, possibly non-stationary. The Mt/Gt/∞ queue is an infinite-server queue with a stationary or non-stationary Poisson arrival process and a general server in which the service time of a customer may depend upon the customer's arrival time. Mirasol (1963) pointed out that the departure process from the M/G/∞ queue is a stationary Poisson process. The question arose whether there are any other Mt/Gt/∞ queueing systems with stationary Poisson departure processes. For example, if the arrival rate is periodic, is it possible to select the service-time distribution functions to fluctuate in order to compensate for the fluctuations of the arrival rate? In this situation and in more general situations, it is possible to select the server such that the system yields a stationary Poisson departure process.

Download Full-text