A novel 90xB0; phase shifter for square waves

In the field of electronic instrumentation there are many applications where a circuit is needed to shift the use of square waves by 90xB0;. In this paper a simple and novel scheme to achieve this end is proposed. This circuit, along with a modulo-two-adder, also enables one to obtain the double frequency component of the original input square wave. It is thus possible to have frequency multiplication by powers of two by cascading such circuits in tandem. The entire circuitry, excepting the time averaging capacitors, can be either13; integrated in one chip or fabricated in tins module form

Characterizing the geometrical edges of nonlocal two-qubit gates

Nonlocal two-qubit gates are geometrically represented by tetrahedron known as Weyl chamber within which perfect entanglers form a polyhedron. We identify that all edges of the Weyl chamber and polyhedron are formed by single parametric gates. Nonlocal attributes of these edges are characterized using entangling power and local invariants. In particular, SWAP (power)alpha family of gates constitutes one edge of the Weyl chamber with SWAP-1/2 being the only perfect entangler. Finally, optimal constructions of controlled-NOT using SWAP-1/2 gate and gates belong to three edges of the polyhedron are presented.Comment: 11 pages, 4 figures, Phys. Rev. A 79, 052339 (2009

Logahedra: A new weakly relational domain

Weakly relational numeric domains express restricted classes of linear inequalities that strike a balance between what can be described and what can be efficiently computed. Popular weakly relational domains such as bounded differences and octagons have found application in model checking and abstract interpretation. This paper introduces logahedra, which are more expressiveness than octagons, but less expressive than arbitrary systems of two variable per inequality constraints. Logahedra allow coefficients of inequalities to be powers of two whilst retaining many of the desirable algorithmic properties of octagons

Vere-Jones' Self-Similar Branching Model

Motivated by its potential application to earthquake statistics, we study the exactly self-similar branching process introduced recently by Vere-Jones, which extends the ETAS class of conditional branching point-processes of triggered seismicity. One of the main ingredient of Vere-Jones' model is that the power law distribution of magnitudes m' of daughters of first-generation of a mother of magnitude m has two branches m'm with exponent beta+d, where beta and d are two positive parameters. We predict that the distribution of magnitudes of events triggered by a mother of magnitude $m$ over all generations has also two branches m'm with exponent beta+h, with h= d \sqrt{1-s}, where s is the fraction of triggered events. This corresponds to a renormalization of the exponent d into h by the hierarchy of successive generations of triggered events. The empirical absence of such two-branched distributions implies, if this model is seriously considered, that the earth is close to criticality (s close to 1) so that beta - h \approx \beta + h \approx \beta. We also find that, for a significant part of the parameter space, the distribution of magnitudes over a full catalog summed over an average steady flow of spontaneous sources (immigrants) reproduces the distribution of the spontaneous sources and is blind to the exponents beta, d of the distribution of triggered events.Comment: 13 page + 3 eps figure

Entangling characterization of (SWAP)1/m and Controlled unitary gates

We study the entangling power and perfect entangler nature of (SWAP)1/m, for m>=1, and controlled unitary (CU) gates. It is shown that (SWAP)1/2 is the only perfect entangler in the family. On the other hand, a subset of CU which is locally equivalent to CNOT is identified. It is shown that the subset, which is a perfect entangler, must necessarily possess the maximum entangling power.Comment: 12 pages, 1 figure, One more paragraph added in Introductio

On an error term related to the Jordan totient function Jk(n)

AbstractWe investigate the error terms Ek(x)=∑n⩽xJk(n)−xk+1(k+1)ζ(k+1) for k⩾2, where Jk(n) = nkΠp|n(1 − 1pk) for k ≥ 1. For k ≥ 2, we prove ∑n⩽xEk(n)∼xk+12(k+1)ζ(k+1). Also, lim infn→∞Ek(x)xk⩽Dζ(k+1), where D = .7159 when k = 2, .6063 when k ≥ 3. On the other hand, even though lim infn→∞Ek(x)xk⩽−12ζ(k+1), Ek(n) > 0 for integers n sufficiently large

Source-to-Source Refactoring and Elimination of Global Variables in C Programs

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author’s publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.A global variable in C/C++ is one that is declared outside a function, and whose scope extends the lifetime of the entire program. Global variables cause problems for program dependability, maintainability, extensibility, verification, and thread-safety. However, global variables can also make co ding more convenient and improve program performance. We have found the use of global variables to remain unabated and extensive in real-world software. In this paper we present a source-to-source refactoring tool to au tomatically detect and localize global variables in a program. We implement a compiler based transformation to find the best location to redefine each global va riable as a local. For each global, our algorithm initializes the corresponding new local variable, pa sses it as an argument to necessary functions, and updates the source lines that used the global to now instead use th e corresponding local or argumen t. We also characterize the use of global variables in standard benchmark programs. We study the effect of our transformation on static program properties, such as change in the number of function ar guments and program state visibility. Additionally, we quantify dynamic program features, including memory and runtime performance, before and after our localizing transformation

Assessment of the impacts of bamboo promotion on soil conservation and people’s livelihood in Gataraga sector, Musanze district, northern Rwanda

This study aimed at assessing the impacts of Bamboo promotion for soil conservation and improved people’s livelihood around Volcanoes National Park (BASOLI/VNP) Project in Gataraga Sector, Musanze District in Northern Province of Rwanda. Problems linked to poverty, bamboo collection andsoil erosion are highlighted in Gataraga Sector, the reason why this study was conducted from May to August 2012. Formal, informal interviews and field observation were used to collect data. 41 respondents from Rungu and Mudakama Cells in Gataraga Sector were interviewed. The data wasanalyzed using Microsoft Office Excel and the Statistical Package for the Social Science (SPSS) 16 using Freidman test, one sample T-Test and paired samples T-Test. Results revealed that the household income and the social services are independent on bamboo production. Farmers got more income after joining Abadacogora cooperative than before the arrival of BASOLI/VNP project (t = -6.815, p = 0.00). The provision of the health services and better education were the main social services achieved. 34 respondents considered the soil erosion control as the first advantage frombamboo plantation. Cooperatives were considered as an essential pillar in the development process of the members in order to increase household income and improve people’s welfare. There is a need to integrate local people into VNP management by increasing awareness on bamboo  importance, promote bamboo plantation in tree campaign program and finance micro project for poor people living around VNP.Keywords: Bamboo, soil erosion, local people’ livelihood, household income, biodiversity conservatio