4,824 research outputs found
New recurrence relationships between orthogonal polynomials which lead to new Lanczos-type algorithms
Lanczos methods for solving Ax = b consist in constructing a sequence of vectors (Xk),k = 1,... such that rk = b-AXk= Pk(A)r0, where Pk is the orthogonal polynomial of degree at most k with respect to the linear functional c defined as c(εi) = (y, Air0). Let P(1)k be the regular monic polynomial of degree k belonging to the family of formal orthogonal polynomials (FOP) with respect to c(1) defined as c(1)(εi) = c(εi+1). All Lanczos-type algorithms are characterized by the choice of one or two recurrence relationships, one for Pk and one for P(1)k. We shall study some new recurrence relations involving these two polynomials and their possible combinations to obtain new Lanczos-type algorithms. We will show that some recurrence relations exist, but cannot be used to derive Lanczos-type algorithms, while others do not exist at all
A preemptive restarting approach to beating the inherent instability of Lanczos-type algorithms
A Search for an Optimum Currency Area Partners for Pakistan
This paper empirically examines the existence of a common trend between the exchange rates of Pakistan and four regional countries (Bangladesh, India, Saudi Arabia, and Sri Lanka) with two of their major trading partners (the United States and Japan) as base countries. Results from cointegrating analysis show that the strongest evidence points to the existence of common stochastic trends between the Pakistani rupee, on the one hand, and the Bangladeshi Taka and the Sri Lankan rupee, on the other hand. There is no strong evidence for the existence of a common stochastic trend between the Pakistani rupee and the currencies of India and Saudi Arabia. Optimum Currency Area (OCA) theory seems to justify the formation of a currency union between Pakistan, Bangladesh, and Sri Lanka. The case of a currency union between Bangladesh and Pakistan is strengthened by a shared political past and a shared history of financial institutional development. The immediate impact of the formation of such union on Pakistan’s GDP growth will however be insignificant.Currency, pakistan
Empirical Comparisons of Virtual Environment Displays
There are many different visual display devices used in virtual environment (VE) systems. These displays vary along many dimensions, such as resolution, field of view, level of immersion, quality of stereo, and so on. In general, no guidelines exist to choose an appropriate display for a particular VE application. Our goal in this work is to develop such guidelines on the basis of empirical results. We present two initial experiments comparing head-mounted displays with a workbench display and a foursided spatially immersive display. The results indicate that the physical characteristics of the displays, users' prior experiences, and even the order in which the displays are presented can have significant effects on performance
An Invariant Dual-beam Snowflake Antenna for Future 5G Communications
A broadband snowflake antenna for future 5G and millimeter-wave communications is presented. The proposed antenna has a size of 8 × 5 mm 2 . The antenna consists of a central hexagon surrounded by a series of symmetrically placed smaller hexagons around it, resulting in broadband characteristics. The impedance bandwidth of the proposed antenna ranges from 25.284-29.252 GHz. The antenna has a gain of 3.12 dBi at 28 GHz and is more than 98% efficient. A distinct feature of the proposed antenna is its dual-beam radiation pattern. The two beams remain fixed at ±50° even if the frequency is varied with in its operating band. The proposed antenna is modelled on thin Rogers substrate which makes it very useful for future 5G smart phones
Webs of Resistance: The Citizen Online Journalism of the Nigerian Digital Diaspora
The enhanced discursive opportunity structures that the Internet enables has inspired a momentous revolution in the Nigerian media landscape. This dissertation chronicles the emergence and flowering of the citizen and alternative online journalism of the Nigerian diasporic public sphere located primarily in the United States. Using case-study research, it profiles the major diasporan online citizen media outlets and highlights instances where these geographically distant citizen media sites shaped and influenced both the national politics and policies of the homeland and the media practices of the domestic media formation.
The study makes the case that while it is customary in the scholarship on sovereignty, state-civil society relations, and diaspora studies to emphasize domination and one-dimensionality in cultural flows, the participation of members of the Nigerian digital diaspora in the politics and discourses of their homeland, from their exilic locations in the West through the instrumentality of online citizen media, illustrates that citizens, especially in the age of the Internet, are not mere powerless subjects and receivers of informational flows from the institutions of the state and corporate mass media but can be active consumers and producers of informational resources and even purveyors of political power in ways that amply exemplify trans-local reciprocality.
It also argues that the Nigerian diaspora media might very well be a prototype of an evolving, Internet-enabled, trans-local, and mutual informational and cultural exchange between the educated deterritorialized ethnoscapes of peripheral nations whose exile in the West endues them with symbolic and cultural capital and the private institutions and governments of their homelands. The study recommends a comparative study of the online citizen journalism of Third World virtual diasporas in the West
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