Maximum Throughput of a Secondary User Cooperating with an Energy-Aware Primary User

This paper proposes a cooperation protocol between a secondary user (SU) and a primary user (PU) which dedicates a free frequency subband for the SU if cooperation results in energy saving. Time is slotted and users are equipped with buffers. Under the proposed protocol, the PU releases portion of its bandwidth for secondary transmission. Moreover, it assigns a portion of the time slot duration for the SU to relay primary packets and achieve a higher successful packet reception probability at the primary receiver. We assume that the PU has three states: idle, forward, and retransmission states. At each of these states, the SU accesses the channel with adaptive transmission parameters. The PU cooperates with the SU if and only if the achievable average number of transmitted primary packets per joule is higher than the number of transmitted packets per joule when it operates alone. The numerical results show the beneficial gains of the proposed cooperative cognitive protocol.Comment: Accepted WiOpt 201

Band Allocation for Cognitive Radios with Buffered Primary and Secondary Users

In this paper, we study band allocation of $\mathcal{M}_s$ buffered secondary users (SUs) to $\mathcal{M}_p$ orthogonal primary licensed bands, where each primary band is assigned to one primary user (PU). Each SU is assigned to one of the available primary bands with a certain probability designed to satisfy some specified quality of service (QoS) requirements for the SUs. In the proposed system, only one SU is assigned to a particular band. The optimization problem used to obtain the stability region's envelope (closure) is shown to be a linear program. We compare the stability region of the proposed system with that of a system where each SU chooses a band randomly with some assignment probability. We also compare with a fixed (deterministic) assignment system, where only one SU is assigned to one of the primary bands all the time. We prove the advantage of the proposed system over the other systems.Comment: Accepted in WCNC 201

Cooperative Cognitive Relaying Under Primary and Secondary Quality of Service Satisfaction

This paper proposes a new cooperative protocol which involves cooperation between primary and secondary users. We consider a cognitive setting with one primary user and multiple secondary users. The time resource is partitioned into discrete time slots. Each time slot, a secondary user is scheduled for transmission according to time division multiple access, and the remainder of the secondary users, which we refer to as secondary relays, attempt to decode the primary packet. Afterwards, the secondary relays employ cooperative beamforming to forward the primary packet and to provide protection to the secondary destination of the secondary source scheduled for transmission from interference. We characterize the diversity-multiplexing tradeoff of the primary source under the proposed protocol. We consider certain quality of service for each user specified by its required throughput. The optimization problem is stated under such condition. It is shown that the optimization problem is linear and can be readily solved. We show that the sum of the secondary required throughputs must be less than or equal to the probability of correct packets reception.Comment: This paper was accepted in PIMRC 201

On Orthogonal Band Allocation for Multi-User Multi-Band Cognitive Radio Networks: Stability Analysis

In this work, we study the problem of band allocation of $M_s$ buffered secondary users (SUs) to $M_p$ primary bands licensed to (owned by) $M_p$ buffered primary users (PUs). The bands are assigned to SUs in an orthogonal (one-to-one) fashion such that neither band sharing nor multi-band allocations are permitted. In order to study the stability region of the secondary network, the optimization problem used to obtain the stability region's envelope (closure) is established and is shown to be a linear program which can be solved efficiently and reliably. We compare our orthogonal allocation system with two typical low-complexity and intuitive band allocation systems. In one system, each cognitive user chooses a band randomly in each time slot with some assignment probability designed such that the system maintained stable, while in the other system fixed (deterministic) band assignment is adopted throughout the lifetime of the network. We derive the stability regions of these two systems. We prove mathematically, as well as through numerical results, the advantages of our proposed orthogonal system over the other two systems.Comment: Conditional Acceptance in IEEE Transactions on Communication

Association Between Joint Hypermobility Syndrome and Developmental Coordination Disorder – A Review.

Introduction: The term joint hypermobility syndrome (JHS) was adopted after clinicians became aware of the myriad of symptoms associated with this multisystemic condition. JHS is an inherited disorder of connective tissues affecting the musculoskeletal and visceral systems which may contribute to a reduction in health related physical fitness. Pain associated with JHS may be influenced by hypermobility and biomechanical dysfunction. Biomechanical dysfunction observed in patients with JHS may be as a result of impaired motor control and in particular developmental coordination disorder (DCD). DCD (described in the literature utilising the terms clumsy child syndrome; perceptual motor dysfunction; dyspraxia) is a neurodevelopmental condition characterised by coordination difficulties affecting function. The objective of this review is to examine the association between hypermobility, JHS, motor control impairment and DCD. Methods and data sources: EMBASE, MEDLINE, CINAHL, ASSIA, PsychARTICLES, SPORTDiscus and PsycINFO from 1989 - 2009. Research articles written in English and peer reviewed were included. Results: Five research papers were identified. The studies employed a variety of methodologies and assessment tools for reporting joint hypermobility, JHS, motor delay, motor impairments and DCD. All five studies reported on children between the ages of six months and 12 years. Three out of four studies reported on association between impaired motor development, motor delay and joint hypermobility. There was no consensus as to whether motor delay, impaired motor development and joint hypermobility continued as the child matured. One study ascertained that children with JHS reported similar functional difficulties as children with DCD. Conclusion: There was a paucity of literature relating to an association between joint hypermobility, JHS, impaired motor control, motor delay and DCD in children, there was no literature pertaining to adults. This association requires further exploration if professionals are to understand, nurture and manage those reporting these associated conditions

System and method for randomized antenna allocation in asynchronous MIMO multi-hop networks

A system and method for simultaneous and asynchronous transmissions in multi-antenna multi-hop networks. The system and method employ randomized and non-greedy resource allocation to counter starvation. The system and method define a class of asynchronous random access protocols subsuming MIMO systems via two components. Residual Capacity Estimation and Randomized Resource Allocation. The system and method realize the first asynchronous MIMO MAC protocol that counters flow starvation in multi-hop networks. Randomized and non-greedy antenna allocation coupled with local residual capacity estimation results in previously-starving nodes capturing a fair share of system resources while simultaneously exploiting throughput gains available to multi-antenna systems

Haemoglobinopathies and health care provision for ethnic minorities

The level of training and competence in dealing with haemoglobinopathies (which mainly affect ethnic minorities in the UK) may not be totally adequate among nurses. Nurses indicated that they received little or no information in their teaching for working from a multiracial perspective and what they had learned was through experience and personal research since qualifying as nurses. Knowledge of the biological basis of inheritance, methods of acquisition of thalassaemia and sicklecell anaemia and the ethnic profile of people affected by these conditions may not be totally adequate among nurses. Many nurses wanted more training, including those who had already received instruction, since this was described as ‘far too vague’, ‘not constructive’, ‘minimal’, or ‘embarrassingly insufficient’, recommending that instruction be given by a sickle-cell anaemia/thalassaemia counsellor with a contribution from patients. A combination of poor quality, or lack, of instruction, together with time and resource pressures, is responsible for this limited understanding, resulting in insufficient awareness of the health needs of ethnic minorities leading to inequalities in healthcare provision

The Impact of Dynamic Capability on Innovation (An Applied Study on Jordanian Pharmaceutical Organizations)

The aim of this research study is to identify the impact of dynamic capability on product innovation, supply chain innovation and organizational innovation. Data were collected using questionnaires from 188 middle and top managers in the Jordanian pharmaceutical organizations. The collected data were analyzed using descriptive statistics and structural equation model (SEM) to test the study hypotheses using AMOS 18.0. The results of the study showed that there is a significant impact for dynamic capability (technical capability, Research &development (R&D) capability and human resource capability) on innovation (product innovation, supply chain innovation and organizational innovation). These results are very likely due to the increased importance of dynamic capabilities in today's organizations. The most important recommendation is adapting new technologies and extensive employee involvement in the entire process of innovation. Keywords: Dynamic Capability, Innovation, Technical Capability, R&D Capability, Human Resource Capability, Product Innovation, Supply Chain Innovation, Organizational Innovation