Optimal Power Allocation for Channel Estimation in MIMO-OFDM System with Per-Subcarrier Transmit Antenna Selection

A novel hybrid channel estimator is proposed for multiple-input multiple-output orthogonal frequency- division multiplexing (MIMO-OFDM) system with per-subcarrier transmit antenna selection having optimal power allocation among subcarriers. In practice, antenna selection information is transmitted through a binary symmetric control channel with a crossover probability. Linear minimum mean-square error (LMMSE) technique is optimal technique for channel estimation in MIMO-OFDM system. Though LMMSE estimator performs well at low signal to noise ratio (SNR), in the presence of antenna-to-subcarrier-assignment error (ATSA), it introduces irreducible error at high SNR. We have proved that relaxed MMSE (RMMSE) estimator overcomes the performance degradation at high SNR. The proposed hybrid estimator combines the benefits of LMMSE at low SNR and RMMSE estimator at high SNR. The vector mean square error (MSE) expression is modified as scalar expression so that an optimal power allocation can be performed. The convex optimization problem is formulated and solved to allocate optimal power to subcarriers minimizing the MSE, subject to transmit sum power constraint. Further, an analytical expression for SNR threshold at which the hybrid estimator is to be switched from LMMSE to RMMSE is derived. The simulation results show that the proposed hybrid estimator gives robust performance, irrespective of ATSA error

Global imbalances: Is Germany the new China? A skeptical view

In this paper we evaluate the current account patterns of China and Germany. We point out that China's current account surplus as a share of global GDP in recent years resembles that of Germany’s. Yet, an important difference is that the Euro block’s current account inclusive of Germany, has overall been balanced, whereas emerging Asia's current account inclusive of China, has mostly been characterized by sizable surpluses. We further find that both China and Germany's current account surpluses seem to be accounted for by common factors. However we have reasons to doubt the long run viability of these current account trends in future decades. Demographic transitions in China and Germany are projected to reduce their surpluses, and this effect is stronger for Germany. We also discuss plausible reasons to doubt the extent to which the Euro block will move towards significant surplus in the coming years.current accounts, demographic transitions, global imbalances

Fast Implementation of Transmit Beamforming for Colocated MIMO Radar

Multiple-input Multiple-output (MIMO) radars benefit from spatial and waveform diversities to improve the performance potential. Phased array radars transmit scaled versions of a single waveform thereby limiting the transmit degrees of freedom to one. However MIMO radars transmit diverse waveforms from different transmit array elements thereby increasing the degrees of freedom to form flexible transmit beampatterns. The transmit beampattern of a colocated MIMO radar depends on the zero-lag correlation matrix of different transmit waveforms. Many solutions have been developed for designing the signal correlation matrix to achieve a desired transmit beampattern based on optimization algorithms in the literature. In this paper, a fast algorithm for designing the correlation matrix of the transmit waveforms is developed that allows the next generation radars to form flexible beampatterns in real-time. An efficient method for sidelobe control with negligible increase in mainlobe width is also presented

Accumulation of reserves and keeping up with the Joneses: the case of LATAM economies

In this paper we explore the ‘Mrs. Machlup's Wardrobe’ hypothesis to understand the growing trend of Latin American economies amassing large stocks of international reserves. Using annual data from 1980 to 2007, we examine the relevance of the argument that economies continue to add to their existing reserves stock in order to keep up with the Joneses. We find strong evidence of presence of the Joneses effect. The effect is robust to the inclusion of traditional determinants of reserve accumulation as well as region specific factors including commodity exports that set the Latin American economies apart from other emerging economies.Demand for international reserves; ‘Mrs. Machlup's Wardrobe’ hypothesis; Speculative attack; Competitive hoarding Financial crisis

BI-GELS: A NOVEL MATERIAL FOR TRANSDERMAL DRUG DELIVERY

Bi-gels semi solid formulation is combination of organogel and hydrogel with better application property such as pharmaceutical and cosmetics. The main objective of this review is specially focuses on application of bi-gels as drug delivery vehicles by transdermal route. It contains two different phases which are polar and nonpolar due to which, it possess some significant features such as ability to deliver the hydrophilic and hydrophobic drugs which also have improved permeability of drugs, better spreading ability, and water wash ability. Hence, bigels have both organogels and hydrogels they can enhanced hydration of stratum corneum and also had an ability to manipulate the drug release rate from the dosage from

Data Leakage Detection by Using Fake Objects

Modern business activities rely on extensive email exchange. Email leakage have became widespread throughout the world, and severe damage has been caused by these leakages it constitutes a problem for organization. We study the following problem: A data distributor has given sensitive data to a set of supposedly trusted agents (third parties).If the data distributed to the third parties is found in a public\private domain then finding the guilty party is a nontrivial task to a distributor. Traditionally, this leakage of data has handled by water marking technique which requires modification of data. If the watermarked copy is found at Some unauthorized site then distributor claim his ownership. To overcome the disadvantage of using watermark, data allocation strategies are used to improve the probability of identifying guilty third parties. The distributor must assess the likelihood that the leaked data come from one or more agents, as opposed to having been gathered from other means. In this project, we implement and analyze a guilt model that detects the agents using allocation strategies without modifying the original data .the guilt agent is one who leaks a portion of distributed data. We propose data 201C;realistic but fake201D; data records to further improve our chances of detecting leakage and identifying the guilty party. And Algorithms implemented using fake objects will improve the distributor chance of detecting the guilt agent. It is observed that by minimizing the sum objective the chance of detecting guilt agents will increase. We also develop a framework for generating fake objects

Community building, multiculturalism and the suburban public library

This research investigates the role of public libraries in building communities and cross-cultural citizenship through provision of equitable information resources and services to English as Additional Language (EAL) speakers, particularly in metropolitan Perth, Western Australia. The rapidly changing demographic profile of Western Australia is producing an ever increasing diversity of people who need to access information in order to thrive in their new community. However, access to these information services pose challenges to users who lack competency in language, computer and general literacy, while the increasing diversity in the local population creates widely divergent competencies in information seeking skills among library clients. Diversity, which has become evident in many contemporary communities, unveils a wide range of information seeking skills, which varies from individuals who are illiterate (often from an agrarian background) and others who are highly educated with substantial English language and computer skills. In this research, the concept of equity in the provision of library services for EAL speakers was investigated by reviewing the library environment in Perth, Western Australia from the perspective of library staff and EAL clients. In-depth interviews were conducted with participants from across various EAL backgrounds as to their knowledge, understanding and current usage of library services. The interview sessions identified the extent of user acceptance of these services and the factors which indicated levels of perceived equity of these library services. The findings from the responses of the public library staff and EAL speakers revealed a complex and diverse local library environment. The public library system, in Western Australia traditionally modelled to serve English language clientele, is yet to fully recognise the presence of the multicultural clientele in its library service provision. Thus, the shift in public library perspectives towards service provision for diverse ethnic groups is evident in isolation but not in adherence to a transparent, consistent government policy which filters down to the local libraries as a guide for normal practices. The EAL speakers’ responses revealed a dire need for English language and computer skills education for some ethnic groups, in order to facilitate their public library access. The findings revealed that some of the EAL groups are unaware of the public library system, its intrinsic value or its culture including that the services are free and offered in a democratic and safe space. Some of the EAL groups also distrust government entities and figures of authority per se as officials symbolise maltreatment of their families and ethnic groups in their countries of origin. Reliance on natives from their own communities, revealed within the interview data, has led to an emergence of bonding social capital tendencies and limited integration with the host culture. The public library is strategically located to draw diverse individuals from its local suburb and contribute towards community building strategies and integration in Western Australia. Having located gaps between library service provision and library service needs, this research developed a model for possible future strategic directions for public libraries in Western Australia