Natural phenomena

This research investigates the challenges and incentives that drive undergraduate students to engage in scientific inquiry. Subsequently, in accordance with this theoretical framework, “Tinto’s Persistence Theory” a model of approaches was generated to encourage undergraduate students in Vietnam to do more high-quality scientific research.

7p vifilm 11-10-2024 3 1   Download

The research also applied historical method and logical method. Specifically, in historical method, the author perceived things and phenomena according to the chronological process (through different time milestones), and the logical method enabled the author to connect all events' sequences and discover the nature of research object. Periodization was also used to study more deeply and discover characteristics of objects and phenomena in specific historical periods.

13p mmlemmlem_124 22-12-2020 18 2   Download

This paper describes a model of syntactical analysis. It shows first how a context-free grammar formalism can be modified in order to reduce the number of rules required by a natural language, and second, how this formalism can be extended to the handling of some non-contextfree phenomena. The description of the algorithm is also given.

11p nghetay_1 06-04-2013 39 2   Download

The main question studied in this article may be viewed as a nonlinear analogue of Dvoretzky’s theorem in Banach space theory or as part of Ramsey theory in combinatorics. Given a finite metric space on n points, we seek its subspace of largest cardinality which can be embedded with a given distortion in Hilbert space. We provide nearly tight upper and lower bounds on the cardinality of this subspace in terms of n and the desired distortion. Our main theorem states that for any 0, every n point metric space contains a subset of size at least n1−...

68p noel_noel 17-01-2013 37 5   Download

The sustainability and prosperity of the ancient civilizations of China, Egypt, Babylonia, Phoenicia, Persia and Roma were based on the extensive use of water for human consumption, crop irrigation, canal navigation and energy generation. Today, the worldwide scarcity of water and clean energy constitutes a central and critical problem for the whole humankind. This situation is aggravated as industrial, agricultural and municipal effl uents reach the water bodies, or the coastal seawater that is used as feed for desalination plants.

346p ktcn_1 10-07-2012 115 13   Download

A combinatorial bijection between k-edge colored trees and colored Pr¨ufer codes for labelled trees is established. This bijection gives a simple combinatorial proof for the number k(n − 2)!nk−n n−2
of k-edge colored trees with n vertices.A k-edge colored tree is a labelled tree whose edges are colored from a set of k colors such that any two edges with a common vertex have different colors

7p thulanh5 12-09-2011 84 7   Download

It is shown that if a d-regular graph contains s vertices so that the distance between any pair is at least 4k, then its adjacency matrix has at least s eigenvalues which are at least 2pd − 1 cos(  2k ). A similar result has been proved by Friedman using more sophisticated tools.More generally, Serre has shown (see [3], [4] ) that for any fixed r and for any infinite family of d-regular graphs Gi, lim inf r(Gi) 2pd − 1. The same result has been proved by Friedman already in [5].

4p thulanh5 12-09-2011 97 6   Download

Subject Geography is the study of variation in the spatial position of natural phenomena and man on Earth.Topics include: The location on Earth and in space, Civilized areas such as national or local city and, The science related to geographical

52p thachthaoxanh 24-08-2011 55 5   Download

Geography is the study of the transformation of spatial location of natural and human phenomena on Earth. Topics include: The location on Earth and in space Civilized areas such as national or local city and Sciences related to geography

37p thachthaoxanh 24-08-2011 87 9   Download

The nation’s top scientists and spies are collaborating on an effort to use the federal government’s intelligence assets — including spy satellites and other classified sensors — to assess the hidden complexities of environmental change. They seek insights from natural phenomena like clouds and glaciers, deserts and tropical forests.

6p phamthithuthuy 09-01-2010 89 6   Download

Investigation of the magnetic properties of materials is very important, because magnetic phenomena have various scientific and technical applications. The macroscopic properties of matter are a manifestation of the microscopic properties of the atoms of which it is composed. The magnetic properties of materials may be very different for types of material, depending on their nature and structure.

19p thanhan 22-07-2009 172 16   Download