Capacity and resource allocation of cooperative MIMO in ad hoc networks

Cooperative MIMO (Multiple Input–Multiple Output) allows multiple nodes share their antennas to emulate antenna arrays and transmit or receive cooperatively. It has the ability to increase the capacity for future wireless communication systems and it is particularly suited for ad hoc networks. In this study, based on the transmission procedure of a typical cooperative MIMO system, we first analyze the capacity of single-hop cooperative MIMO systems, and then we derive the optimal resource allocation strategy to maximize the end-to-end capacity in multi-hop cooperative MIMO systems. The study shows three implications. First, only when the intra-cluster channel is better than the inter-cluster channel, cooperative MIMO results in a capacity increment. Second, for a given scenario there is an optimal number of cooperative nodes. For instance, in our study an optimal deployment of three cooperative nodes achieve a capacity increment of 2 bps/Hz when compared with direct transmission. Third, an optimal resource allocation strategy plays a significant role in maximizing end-to-end capacity in multi-hop cooperative MIMO systems. Numerical results show that when optimal resource allocation is applied we achieve more than 20% end-to-end capacity increment in average when compared with an equal resource allocation strategy.

On the Performance of Eigenvalue-Based Cooperative Spectrum Sensing for Cognitive Radio

In this paper, the distribution of the ratio of extreme eigenvalues of a complex Wishart matrix is studied in order to calculate the exact decision threshold as a function of the desired probability of false alarm for the maximum-minimum eigenvalue (MME) detector. In contrast to the asymptotic analysis reported in the literature, we consider a finite number of cooperative receivers and a finite number of samples and derive the exact decision threshold for the probability of false alarm. The proposed exact formulation is further reduced to the case of two receiver-based cooperative spectrum sensing. In addition, an approximate closed-form formula of the exact threshold is derived in terms of a desired probability of false alarm for a special case having equal number of receive antennas and signal samples. Finally, the derived analytical exact decision thresholds are verified with Monte-Carlo simulations. We show that the probability of detection performance using the proposed exact decision thresholds achieves significant performance gains compared to the performance of the asymptotic decision threshold.

The Impact of Shame on the Therapeutic Alliance and Intimate Relationships

Objectives


This study examined the role of shame coping styles and state shame in predicting the therapeutic alliance and intimate relationship functioning in individuals with mental health problems.


Method


A sample of 50 treatment-receiving adults aged 21 to 67 years with a mix of common mental health difficulties was recruited from a clinical psychology service. Participants were given questionnaire measures of shame states, shame coping styles, intimate relationship functioning, and the therapeutic alliance.


Results


Regression analyses indicated that the shame coping strategy of physical and psychological withdrawal was the primary risk factor for development of a less effective therapeutic alliance. Both withdrawal and attack self coping styles were significant predictors of impaired intimate relationship functioning.


Conclusions


These findings have implications for the theoretical role of shame in mental health presentations as well as the potential for internalizing shame coping styles (i.e., withdrawal, attack self) to act as a barrier to successful therapy and interpersonal relationships. The inclusion of shame-focused assessments and interventions in the initial stages of treatment with clients exhibiting these strategies could improve prognosis.

Cooperative bank efficiency in Japan: a parametric distance function analysis

This study examines the relative performance of Japanese cooperative banks between 1998 and 2009, explicitly modeling non-performing loans as an undesirable output. Three key findings emerge. First, the sector is characterized by increasing returns to scale which supports the ongoing amalgamation process within the sector. Second, although restricted in product offerings, markets and their membership base, Japanese cooperatives secured both technical progress (a positive shift in the frontier) and a decrease in technical inefficiency (distance from the frontier). Third, the analysis highlighted that regulatory pressure to reduce non-performing loans will have an adverse impact on both output and performance. 

Changing climate, changing process: implications for salt transportation and weathering within building sandstones in the UK

Salt weathering is a crucial process that brings about a change in stone, from the scale of landscapes to stone outcrops and natural building stone facades. It is acknowledged that salt weathering is controlled by fluctuations in temperature and moisture, where repeated oscillations in these parameters can cause re-crystallisation, hydration/de-hydration of salts, bringing about stone surface loss in the form of, for example, granular disaggregation, scaling, and multiple flaking. However, this ‘traditional’ view of how salt weathering proceeds may need to be re-evaluated in the light of current and future climatic trends. Indeed, there is considerable scope for the investigation of consequences of climate change on geomorphological processes in general. Building on contemporary research on the ‘deep wetting’ of natural building stones, it is proposed that (as stone may be wetter for longer), ion diffusion may become a more prominent mechanism for the mixing of molecular constituents, and a shift in focus from physical damage to chemical change is suggested. Data from ion diffusion cell experiments are presented for three different sandstone types, demonstrating that salts may diffuse through porous stone relatively rapidly (in comparison to, for example, dense concrete). Pore water from stones undergoing diffusion experiments was extracted and analysed. Factors controlling ion diffusion
relating to ‘time of wetness’ within stones are discussed, (continued saturation, connectivity of pores, mineralogy, behaviour of salts, sedimentary structure), and potential changes in system dynamics as a result of climate change are addressed. System inputs may change in terms of increased moisture input, translating into a greater depth of wetting front. Salts are likely to be ‘stored’ differently in stones, with salt being in solution for longer periods (during prolonged winter wetness). This has myriad implications in terms of the movement of ions by diffusion and the potential for chemical change in the stone (especially in more mobile constituents), leading to a weakening of the stone matrix/grain boundary cementing. The ‘output’ may be mobilisation and precipitation of elements leading to, for example, uneven cementing in the stone. This reduced strength of the stone, or compromised ability of the stone to absorb stress, is likely to make crystallisation a more efficacious mechanism of decay when it does occur. Thus, a delay in the onset of crystallisation while stonework is wet does not preclude exaggerated or accelerated material loss when it finally happens.

Cooperative traits of technology adoption: Website adoption in Irish credit unions

The purpose of this paper is to examine website adoption and its resultant effects on credit union performance in Ireland. Credit union specific factors influence adoption as does the socio-economic profile of the population from where the credit union draws its membership. Website adoption results in a reduction in the spread between the loan and dividend rate with this primarily driven by a fall in the loan rate. Given that the adoption of a website, albeit with limited functionality, translates into cost benefits this augurs well for the current restructuring process underway for Irish credit unions which has as one of its objectives the upgrade of credit union ICT sophistication.

Simultaneous and cooperative gas storage and gas production using bifunctional zeolites

Nitric oxide can be stored in and produced from zeolites in a simultaneous and cooperative process

Cooperative Learning in Science: Follow-up from primary to high school

This paper reports a two-year longitudinal study of the effects of cooperative learning on science attainment, attitudes towards science, and social connectedness during transition from primary to high school. A previous project on cooperative learning in primary schools observed gains in science understanding and in social aspects of school life. This project followed 204 children involved in the previous project and 440 comparison children who were not as they undertook transition from 24 primary schools to 16 high schools. Cognitive, affective, and social gains observed in the original project survived transition. The implications improving the effectiveness of school transition by using cooperative learning initiatives are explored. Possibilities for future research and the implications for practice and policy are discussed.

Decentralised formation control and stability analysis for cooperative multi-vehicle manoeuvre

Multi-vehicle cooperative formation control problem is an important and typical topic of research on multi-agent system. This paper presents a formation stability conjecture to conceive a new methodology for solving the decentralised multi-vehicle formation control problem. It employs the “extension-decomposition-aggregation” scheme to transform the complex multi-agent control problem into a group of sub-problems which is able to be solved conveniently. Based on this methodology, it is proved that if all the individual augmented subsystems can be stabilised by using any approach, the overall formation system is not only asymptotically but also exponentially stable in the sense of Lyapunov within a neighbourhood of the desired formation. Simulation study on 6-DOF aerial vehicles (Aerosonde UAVs) has been performed to verify the achieved formation stability result. The proposed multi-vehicle formation control strategy can be conveniently extended to other cooperative control problems of multi-agent systems.

Raiffeisenism abroad: why did German cooperative banking fail in Ireland but prosper in the Netherlands?

Why did imitations of Raiffeisen’s rural cooperative savings and loans associations work well in some European countries, but fail in others? This article considers the example of Raiffeisenism in Ireland and in the Netherlands. Raiffeisen banks arrived in both places at the same time, but had drastically different fates. In Ireland they were almost wiped out by the early 1920s, while in the Netherlands they proved to be a long-lasting institutional transplant. Raiffeisen banks were successful in the Netherlands because they operated in niche markets with few competitors, while rural financial markets in Ireland were unsegmented and populated by long- established incumbents, leaving little room for new players, whatever their institu- tional advantages. Dutch Raiffeisen banks were largely self-financing, closely integrated into the wider rural economy, and able to take advantage of economic and religious divisions in rural society. Their Irish counterparts were not.