A downlink power control scheme for interference avoidance in femtocells

Femtocells being small low powered base stations provide sufficient increase in system capacity along with better indoor coverage. However, the dense deployment of femtocells face the main challenge of co channel interference with macrocell users. In this paper, this interference problem is addressed by proposing a novel downlink power control algorithm for femtocells. The proposed algorithm gradually reduces the downlink transmit power of femtocells when they are informed about a nearby macrocell user under interference. This information is given to the femtocells by the macrocell base station through a unidirectional downlink broadcast channel. Simulation results show that the algorithm causes the macrocell to accommodate large number of femtocells within its area, whereas at the same time protecting the macrocell users from any harmful interference.

Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy

The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by haemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology.

Banking compliance and dependence corruption: towards an attachment perspective

Why did banking compliance fail so badly in the recent financial crisis and why, according to many, does it continue to do so? Rather than point to the lack of oversight of individuals in bank compliance roles, as many commentators do, in this paper I examine in depth the organizational context that surrounded people in such roles. I focus on those compliance personnel who did speak out about risky practices in their banks, who were forced to escalate the problem and 'whistle-blow' to external parties, and who were punished for doing so. Drawing on recent empirical data from a wider study, I argue that the concept of dependence corruption is useful in this setting, and that it can be extended to encompass interpersonal attachments. This, in turn, problematises the concept of dependence corruption because interpersonal attachments in organisational settings are inevitable. The paper engages with recent debates on whether institutional corruption is an appropriate lens for studying private-sector organisations by arguing for a focus on roles, rather than remaining at the level of institutional fields or individual organisations. Finally, the paper contributes to studies on banking compliance in the context of the recent crisis; without a deeper understanding of those who were forced to extremes to simply do their jobs, reform of the banking sector will prove difficult.

BER evaluation of a low complexity transmit diversity scheme and its application to MIMO-BICM

In this paper, we first provide a theoretical validation for a low-complexity transmit diversity algorithm which employs only one RF chain and a low-complexity switch for transmission. Our theoretical analysis is compared to the simulation results and proved to be accurate. We then apply the transmit diversity scheme to multiple-input and multiple-output (MIMO) systems with bit-interleaved coded modulation (BICM). © 2012 IEEE.