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On the QoS performance of a converged ONU-BS under self-similar traffic input and low latency queueing discipline
No full textA converged ONU-BS architecture has been proposed for next-generation optical-wireless networks. Further, research and Internet measurements have revealed that both wired and wireless data traffic are selfsimilar and long range dependent. Therefore, to help the understanding of the converged architecture and to facilitate the provisioning of tightly bound QoS parameters to end-users, we present an analysis of the QoS behavior of the converged architecture under self-similar and long range dependent traffic conditions using low latency queuing (LLQ) which is a common queuing discipline that is likely to be used in NGNs. This work extends our previous work on priority queuing (PQ) and brings novelty in terms of presenting performance analysis of the converged ONU-BS under realistic traffic load conditions and with
a more robust queuing discipline. This work shows that QoS parameters such as delay and packet loss are much improved under a robust queuing discipline like LLQ compared with PQ
SVM active learning through significance space construction
No full textActive learning is showing to be a useful approach to improve the efficiency of the classification process for remote sensing images. This letter introduces a new active learning strategy specifically developed for support vector machine (SVM) classification. It relies on the idea of the following: 1) reformulating the original classification problem into a new problem where it is needed to discriminate between significant and non significant samples, according to a concept of significance which is proper to the SVM theory; and 2) constructing the corresponding significance space to suitably guide the selection of the samples potentially useful to better deal with the original classification problem. Experiments were conducted on both multi- and hyperspectral images. Results show interesting advantages of the proposed method in terms of convergence speed, stability, and sparseness
Establishment of Optimal Disjoint Paths in MPLS Networks
No full textMPLS is an IETF-Specified framework providing high reliability of routing, switching & forwarding of traffic flows through the network. Recent augmentation in the internet traffic has made QoS a necessity for large-scale networks. MPLS is currently gaining high values in corporate sector to carry some high value traffic components, such as telephony over IP (ToIP) or VPN’s and for such a service, availability is a critical QoS dimension that needs to be protected from network failures. In order to preserve other QoS requirements, the paths must meet certain constraints (e.g., bandwidth availability & low load) and/or minimize some metric (e.g., minimum hop counts or hop counts with minimum delay). Among the problems that remain unsolved is how to efficiently find & establish optimal primary and backup LSP’s for mission critical services subjecting to QoS constraints. So, in regards to this context we will study three alternative schemes recently proposed [1] for diverse path computation & assess their performance in terms of some QoS metrics as mentioned above, describing the critical problems faced in the research process & present our vision on how to rationally overcome some of the problems exposed
Performance Analysis of a New Delay Enabled EDCF for Voice Transport over IEEE802.11e
No full textA new subfunction for the IEEE 802.11e EDCF allowing efficient transport of real-time traffic is proposed. The delay induced by the freezout of the backoff counter is to be considered. Intentional dropping is used if a certain threshold delay is exceeded. A system enabled with this suggested feature is analyzed and the impact of backoff parameters on the transmission probability, the dropping probability, the transmission delay, in addition to the throughput will be evaluated. The required equations of the Markov chain will be derived, in addition to the equations for delay and throughput
A Class Based and Shared Resources Access Control for Distributed Video-on-Demand system
No full textVideo on Demand (VOD) is a system which allows users to select and watch a video on demand. Number of requests arrives per second for different categories (popular and un-popular) of video. There needs an admission control policy to decide which request can be admitted and which should be rejected but request for popular and expensive movies should not be rejected on the behalf of un-popular videos. Traditional Admission control system uses either threshold or resource capacity to accept or reject any incoming request. The proposed “Class Base and Share Resource admission control policy” (CBSR) is distinctions of this paperfrom the previous work include. (1) A new concept is introduced in this paper that is use of both schemes shared resource admission control and class base admission control.
(2) An other new concept of, Probability is introduced to access the shared resource (Ports, Bandwidth). In the proposed system total capacity of VOD server (ports) is partitioned equal to the number of classes plus shared area. When a request arrives it will be admitted if there is capacity to its corresponding partition if not we will check the capacity of shared area and admit it with some probability. If there is no capacity in shared area or no probability the call will be rejected. The evaluation of proposed system is done bysimulation model, no of blocked requests are calculated for performance measure. It is observed from the simulation results that proposed admission control policy is not only improves the performance of high priority classes but also reduces a lot the total number of rejected requests
A Comparative Study of Statistical Feature Reduction Methods for Arabic Text Categorization
No full textFeature reduction methods have been successfully applied to text categorization. In this paper, we perform a comparative study on three feature reduction methods for text categorization, including Document Frequency (DF), Term Frequency Inverse Document Frequency (TFIDF) and Latent Semantic Analyses (LSA). Our feature set is relatively large (since there are thousands of different terms in different texts files). We propose the use of the previous feature reduction methods as a preprocessor of Back-Propagation Neural Network (BPNN) to reduce the input data on training process. The experimental results on an Arabic data set demonstrate that among the three dimensionality reduction techniques proposed, TFIDF was found to be the most effective in reducing the dimensionality of the feature space
Channel Modeling and Analysis for Wireless Underground Sensor Networks in Soil Medium
No full textWireless underground sensor networks (WUSNs) constitute one of the promising application
areas of the recently developed wireless sensor networking techniques. The main difference
between WUSNs and the terrestrial wireless sensor networks is the communication medium.
The propagation characteristics of electromagnetic (EM) waves in soil and the significant
differences between propagation in air prevent a straightforward characterization of the
underground wireless channel. To this end, in this paper, advanced channel models are
derived to characterize the underground wireless channel and the foundational issues for
efficient communication through soil are discussed. In particular, the underground
communication channel is modeled considering not only the propagation of EM waves in soil,
but also other effects such as multipath, soil composition, soil moisture, and burial depth.
The propagation characteristics are investigated through simulation results of path loss
between two underground sensors. Moreover, based on the proposed channel model, the
resulting bit error rate is analyzed for different network and soil parameters. Furthermore,
the effects of variations in soil moisture are investigated through field measurement results.
The theoretical analysis and the simulation results prove the feasibility of wireless
communication in underground environment and highlight several important aspects in this
field. This work will lead to the provision of a generic framework for underground wireless
communication and the realization of WUSNs
Towards a Distributed Architecture for Adaptive E-Learning System
No full textTechnology is advancing rapidly and the demand and expectation is getting higher, that current monolithic client-server and peer-to-peer e-learning systems can no longer tolerate. Distributed e-learning systems, on the other hand, have the potential to address many shortcomings of current e-learning systems. Distributed systems are mainly based on Web-services or alternatively the Grid. The purpose of this paper is to define a novel distributed e-learning architecture based on multi-agents and intelligent distributed blackboards. The proposed architecture employs the Web-services approach of distributed e-learning systems in a scalable and flexible manner, utilizing a wealth of e-learning content and services in existing on-line learning repositories and intelligently personalizing it to the particular needs of the learners, through the use of multi-agents. Distributed intelligent blackboards, on the other hand, allows the efficient and seamless communication and collaboration among the various distributed agents
Analysis of Consumer Behavior in Supermarkets in Riyadh, Saudi Arabia
No full textThis study investigated the characteristics of supermarkets' customers, the variation of supermarkets relative importance according to the commodity groups and customer characteristics, the motives of buying from them, the pattern of shopping and customer behavior when dealing with them, the influence of prices and the quality of products on purchasing decision It relied on primary data collected from 217 supermarket customers in Riyadh city in 1994
Results showed the high relative importance of supermarkets especially for non Arabs (84%) The most important motives for buying from them are availability of different goods and brands (17.68%), quality and presentation of products (16 05%), buying needs in short time (14 78%), availability of parking area (14.48%), and living close to the supermarket (13.52%). Husbands are the ones who do shopping from supermarkets (81%), more than 50% of customers shop more than 7 times a month, shopping is done more on Thursdays (29%), Fridays (20%), or Wednesdays (17%), and on average a customer needs about 30 minutes for shopping
The results showed that the value of purchased goods in one shopping visit is more for Saudis than others, 75% of buying decisions are based on both price and quality considerations. Saudis complain more than others from high prices, no significant differences in the effect of promotion programs between Saudi and non Saudi customers, about 41% of Saudis and 56% of non Saudis only are satisfied for using supermarkets, and the degree of satisfaction is significantly less for young customers
EFFECT OF CONVENTIONAL AND ELECTRICAL THERMAL STRESSES ON THE DESTRUCTION KINETICS OF SILVANIDAE INSECTS INSIDE THE FRUITS OF SOME DATE VARIETIES
No full textThe goal of this research was to investigate indirect exposure to through immersing three varieties of date's fruits (Sefri, Khudari and Seri) in boiling solution. The heating was introduced by conventional heating and by using electrical conductive method through salt solution to kill Oryzaephils surinamensis: Silvanidae insects. The results indicate that the destruction rate order of the insect can be described successfully by applying zero order kinetics models in both heating mechanism: conventional and electrical. In addition, the destruction of the adults insures the destruction of all other stages of the insect. There was no significant change between the destruction rate when using conventional heating or electrical heating in the case of Sefri and Khudari varieties. However, the rate of destruction by using electrical heating was significantly less than that for conventional heating in the case of Seri variety