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Search Results: 1 - 10 of 139378 matches for " K. Rahimi Malekshan "
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Distributed Cross-layer Dynamic Route Selection in Wireless Multiuser Multihop Networks
K. Rahimi Malekshan,F. Lahouti
Computer Science , 2014,
Abstract: In wireless ad-hoc networks, forwarding data through intermediate relays extends the coverage area and enhances the network throughput. We consider a general wireless multiuser multihop transmission, where each data flow is subject to a constraint on the end-to-end buffering delay and the associated packet drop rate as a quality of service (QoS) requirement. The objective is to maximize the weighted sum-rate between source destination pairs, while the corresponding QoS requirements are satisfied. We introduce two new distributed cross-layer dynamic route selection schemes in this setting that are designed involving physical, MAC, and network layers. In the proposed opportunistic cross-layer dynamic route selection scheme, routes are assigned dynamically based on the state of network nodes' buffers and the instantaneous state of fading channels. In the same setting, the proposed time division cross layer dynamic route selection scheme utilizes the average quality of channels instead for more efficient implementation. Detailed results and comparisons are provided, which demonstrate the superior performance of the proposed cross-layer dynamic route selection schemes.
An Energy Efficient MAC Protocol for Fully Connected Wireless Ad Hoc Networks
K. Rahimi Malekshan,W. Zhuang,Y. Lostanlen
Computer Science , 2014,
Abstract: Energy efficiency is an important performance measure of wireless network protocols, especially for battery-powered mobile devices such as smartphones. This paper presents a new energy-efficient medium access control (MAC) scheme for fully connected wireless ad hoc networks. The proposed scheme reduces energy consumption by putting radio interfaces in the sleep state periodically and by reducing transmission collisions, which results in high throughput and low packet transmission delay. The proposed MAC scheme can also address the energy saving in realtime traffics which require very low packet transmission delay. An analytical model is established to evaluate the performance of the proposed MAC scheme. Analytical and simulation results demonstrate that the proposed scheme has a significantly lower power consumption, achieves substantially higher throughput, and has lower packet transmission delay in comparison with existing power saving MAC protocols.
Coordination-based Medium Access Control with Space-reservation for Wireless Ad Hoc Networks
Kamal Rahimi Malekshan,Weihua Zhuang,Yves Lostanlen
Computer Science , 2015,
Abstract: Efficient radio spectrum utilization and low energy consumption in mobile devices are essential in developing next generation wireless networks. This paper presents a new medium access control (MAC) mechanism to enhance spectrum efficiency and reduce energy consumption in a wireless ad hoc network. A set of coordinator nodes, distributed in the network area, periodically schedule contention-free time slots for all data transmissions/receptions in the network, based on transmission requests from source nodes. Adjacent coordinators exchange scheduling information to effectively increase spatial spectrum reuse and avoid transmission collisions. Moreover, the proposed MAC scheme allows a node to put its radio interface into a sleep mode when it is not transmitting/receiving a packet, in order to reduce energy consumption. Simulation results demonstrate that the proposed scheme achieves substantially higher throughput and has significantly lower energy consumption in comparison with existing schemes.
Case study: Class diagram restructuring
K. Lano,S. Kolahdouz Rahimi
Computer Science , 2013, DOI: 10.4204/EPTCS.135.2
Abstract: This case study is an update-in-place refactoring transformation on UML class diagrams. Its aim is to remove clones of attributes from a class diagram, and to identify new classes which abstract groups of classes that share common data features. It is used as one of a general collection of transformations (such as the removal of redundant inheritance, or multiple inheritance) which aim to improve the quality of a specification or design level class diagram. The transformation is a typical example of a model refactoring, and illustrates the issues involved in such transformations.
Solving the TTC 2011 Model Migration Case with UML-RSDS
K. Lano,S. Kolahdouz-Rahimi
Electronic Proceedings in Theoretical Computer Science , 2011, DOI: 10.4204/eptcs.74.6
Abstract: In this paper we apply the UML-RSDS notation and tools to the GMF model migration case study and explain how to use the UML-RSDS tools.
Saying Hello World with UML-RSDS – A Solution to the 2011 Instructive Case
K. Lano,S. Kolahdouz-Rahimi
Electronic Proceedings in Theoretical Computer Science , 2011, DOI: 10.4204/eptcs.74.26
Abstract: In this paper we apply the UML-RSDS notation and tools to the ``Hello World" case studies and explain the underlying development process for this model transformation approach.
A Novel Design for Quantum-dot Cellular Automata Cells and Full Adders
Mostafa Rahimi Azghadi,O. Kavehie,K. Navi
Computer Science , 2012,
Abstract: Quantum dot Cellular Automata (QCA) is a novel and potentially attractive technology for implementing computing architectures at the nanoscale. The basic Boolean primitive in QCA is the majority gate. In this paper we present a novel design for QCA cells and another possible and unconventional scheme for majority gates. By applying these items, the hardware requirements for a QCA design can be reduced and circuits can be simpler in level and gate counts. As an example, a 1-bit QCA adder is constructed by applying our new scheme and is compared to the other existing implementation. Beside, some Boolean functions are expressed as examples and it has been shown, how our reduction method by using new proposed item, decreases gate counts and levels in comparison to the other previous methods.
A Novel Design for Quantum-dot Cellular Automata Cells and Full Adders
Mostafa Rahimi Azghadi,O. Kavehie,K. Navi
Computer Science , 2012,
Abstract: Erroneous submission in violation of copyright removed by arXiv admin.
H. Kaviani,M. Rahimi,P. Rahimi-Darabad,K. Kamyar H. Naghavi
Acta Medica Iranica , 2003,
Abstract: Over the past decade, there have been several studies showing autobiographical memory retrieval and problem solving deficits in depressed population. The present study aimed to first to examine the roles of autobiographical memory specificity and problemsolving effectiveness in Iranian depressed people with or without suicide ideation and secondly, to test the correlations between autobiographical memory and problem-solving components. A group of depressed patients with suicide ideation (n=20, aged 18-45) and a matched control group (depressed without suicide ideation) were tested by a autobiographical memory test, a means-ends problem-solving task, Beck Depression Inventory (BDI), and Beck Hopelessness Scale (BHS). Both groups met DSM-IV criteria for major depression disorder without psychotic features. In line with hypotheses, the suicide ideators scored significantly higher on the hopelessness scale than the control group. The suicide ideators also provided significantly less effective problem-solving strategies and more over-general memories than the control group. A significant correlation was found between low effectiveness of problem-solving strategies and over-general memory retrieval. The present results suggest that access to non-specific memories in depressed people can lead probably to ineffective problem solutions and subsequently hopelessness and suicide.
Solving the Petri-Nets to Statecharts Transformation Case with UML-RSDS
K. Lano,S. Kolahdouz-Rahimi,K. Maroukian
Computer Science , 2013, DOI: 10.4204/EPTCS.135.13
Abstract: This paper provides a solution to the Petri-Nets to statecharts case using UML-RSDS. We show how a highly declarative solution which is confluent and invertible can be given using this approach.
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