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The dependence of TCP downstream throughput (TCPdownT) on signal to noise ratio (SNR) has been studied in this paper. Measurements were taken for multiple users in small offices, open corridors and free space environments using an infrastructure based IEEE 802.11b WLAN while transmitting different quality of service (QoS) traffic. Models able to predict TCPdownT with respect to SNR observed were developed...
In this paper, we derive an expression for throughput of TCP Compound connections with random losses. We consider the case of a single TCP connection with random losses and negligible queuing, i.e., constant round trip time. For this case, an approximation of throughput has been derived earlier using a deterministic loss model. We provide a theoretical justification for this approximation. Further,...
We study the temporal clustering effects in the computer network traffic on the performance of a node with a given throughput limited by its outgoing channel capacity. The empirical data sets are exemplified by three different HTTP servers. We consider the inter-arrival times and the service times and evaluate the average system performance by the queuing system simulation. Our results indicate that...
Trust is a soft security solution for Ad-hoc Wireless Networks such as Mobile Adhoc Networks (MANETs), Wireless Sensor networks (WSNs). Due to openness of the networks a malicious node can easily join and disrupt the network. Trust models are used to discriminate between legitimate and malicious nodes in the network. The characteristics of MANETs and WSNs are different so, there are some significant...
A distributed and collaborative nature of wireless sensor network cause many challenges to provide security in network. Most of the outsider's attacks are prevented by encryption and authentication technology, but to control insider attacks are difficult. A malicious sensor node causes lot of packet losses, energy wastage and increase in time to reach final destination. In this paper, Enhanced Beta...
Real-time stream processing applications executed on embedded multiprocessor systems often have strict throughput and latency constraints. Violating these constraints is undesired and temporal analysis methods are therefore used to prevent such violations. These analysis methods use abstractions of the analyzed applications to simplify their temporal analysis.
VANET is a part of MANET which is specific on communication between vehicle to vehicle or between vehicles to its surrounding environment infrastructure. One of the most widely used routing protocol at VANET implementation are AODV (Ad-hoc On-Demand Distance Vector) and DSDV (Destination Sequence Distance Vector Routing), which are topology based routing protocol. VANET dynamic network architecture...
The Synchronous Dataflow Graph (SDFG) and Cyclo-Static Dataflow Graph (CSDFG) are two well-known models, used practically by industry for many years, and for which there is a large number of analysis techniques. Yet, basic problems such as the throughput computation or the liveness evaluation are not well solved, and their complexity is still unknown. In this paper, we propose K-Iter, an iterative...
This paper presents the design and implementation of an automatic lecturer availability tracking system incorporating various software and hardware technologies. The system is aimed at reducing the amount of time that students, visitors and faculty members spend looking for specific employees without being hindered by the ethical issues surrounding RFID based staff tracking. It focuses on the availability...
Performance scaling is now synonymous with scaling the number of cores. One of the consequences of this shift is the increasing difficulty of designing processors with predictable and controllable performance. To address this challenge this paper proposes a chip-scale throughput regulation technique that is based on dynamic tracking of instruction execution dynamics in each core. A new variable gain...
In this work, an end-to-end TCP throughput control mechanism based on TCP throughput model is proposed to fulfill the users' QoS requirements. To control end-to-end TCP throughput at single point, it is necessary to enforce a TCP connection operating at a target rate. Therefore, a measurement mechanism is proposed to derive the values of the two control parameters - packet drop rate and round trip...
Hadoop and Storm are playing a significant role in Cloud Computing and either of them has its own applicable area. Cocktail is a new hybrid system that combines Hadoop and Storm into one single system, leveraging the functions of two computing frameworks. The design and implementation of Cocktail includes a SQL-like query language making the implementation of details transparent for users, an intelligent...
In wireless ad hoc networks, misbehavior of nodes in computation of backoff value is one of the problems that affects the performance at MAC layer. To overcome this problem, this paper proposes a solution in which Contention Window subrange is specified by the receiver to the sender through CTS/ ACK packet. The advantage of sending the Contention Window subrange is, it is easier to detect the misbehaving...
Virtual machine consolidation is attractive in cloud computing platforms for several reasons including reduced infrastructure costs, lower energy consumption and ease of management. However, the interference between co-resident workloads caused by virtualization can violate the service level objectives (SLOs) that the cloud platform guarantees. Existing solutions to minimize interference between virtual...
Intelligent data analysis has become more important in the last decade especially because of the significant increase in the size and availability of data. In this paper, we focus on the common execution models and characteristics of iterative graph analytics applications. We show that the features that improve work efficiency can lead to significant overheads on existing systems. We identify the...
Cloud platform providers usually offer several APIs (Application Program Interface) to help facilitate programmers to utilize cloud resources effectively by hiding complex cloud structures and mechanisms. However, there are some aspects of distributed computing that cannot be hidden. Depending on data consistency models, two or more clients may not see the same current state of the data. Developers...
New scheduling algorithms are first evaluated using simulation. In these simulations, the workload has a huge influence on the measured performance of the simulated system. Therefore, it is customary to use workload traces recorded previously from real systems. Such open-system simulations preserve all the jobs' properties. However, preserving the jobs' arrival times actually destroys the logic of...
Cloud Computing has a lot of research emphasis in recent years and it offers a virtual agenda of resource allocation of. In such a purely dispersed environment, an entity has freedom to use pool of resources. Due to compassion and vivacity of data or facts, such objects wish to access their specific closed resources. The user/consumer assumes good quality of service from a reliable service provider...
The FSM-based scenario-aware data ow (FSM-SADF) model of computation has been introduced to facilitate the analysis of dynamic streaming applications. FSM-SADF interprets application's execution as an execution of a sequence of static modes of operation called scenarios. Each scenario is modeled using a synchronous data ow (SDF) graph (SDFG), while a finite-state machine (FSM) is used to encode scenario...
In this paper, we propose an analytic model that takes as inputs a) a parametric microarchitecture-independent characterization of the target workload, and b) a hardware configuration of the core and the memory hierarchy, and returns as output an estimation of processor-core performance. To validate our technique, we compare our performance estimates with measurements on an Intel® Xeon® system. The...
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