757 research outputs found
A study of positive energy condition in Bianchi V spacetimes via Noether symmetries
In this paper we use Noether symmetries of the geodesic Lagrangian in Bianchi
V spacetimes to study various cosmological solutions of Einstein's field
equations. Our first result is the identification of the subalgebras of Noether
symmetries of the equations of motions in such spacetimes with dimension 4, 5,
6, 7, 9 or 10 of the maximal algebra of Lie point symmetries of dimension 13.
Secondly we give physical interpretation of new cosmological solutions which
satisfy positive energy condition and yield critical bounds on the expansion
coefficient , in which the underlying non-flat spacetimes carry
interesting physical properties. Specifically the energy density behaves in one
of the following ways. (i) It is positive and constant for all time. (ii) It
varies with time and attains a global maximum after some time and then
asymptotically converges to zero. (iii) It increases for all time and attains a
maximum value at the asymptotic limit . In particular a
non-flat spacetime is obtained that mimics the expansion in a flat FRW universe
dominated by vacuum energy such that the expansion factor has the same form in
both. However, the energy density is dynamical in the former.Comment: Some typos are corrected. Some considerations into f(R) gravity is
also carried out in the light of obtained results. Accepted for publication
in EPJ
Dynamics of a Charged Particle Around a Slowly Rotating Kerr Black Hole Immersed in Magnetic Field
The dynamics of a charged particle moving around a slowly rotating Kerr black
hole in the presence of an external magnetic field is investigated. We are
interested to explore the conditions under which the charged particle can
escape from the gravitational field of the black hole after colliding with
another particle. The escape velocity of the charged particle in the innermost
stable circular orbit is calculated. The effective potential and escape
velocity of the charged particle with angular momentum in the presence of
magnetic field is analyzed. This work serves as an extension of a preceding
paper dealing with the Schwarzschild black hole [Zahrani {\it et al}, Phys.
Rev. D 87, 084043 (2013)].Comment: 20 pages, 12 figure
Efficient Penetration Policy for Internet Connection in Pakistan Rural Areas
학위논문(석사)--서울대학교 대학원 :공과대학 협동과정 기술경영·경제·정책전공,2016. 2. Lee, Jongsu .Understanding the preferences of Internet users is useful for ICT (information and communication technology) policy and planning. Infrastructure of telecommunication is recognized as the key and fundamental factor for economic and social development outside the limits of geographical boundaries. Beyond Urban communities, Telecommunication technology infrastructure is a necessity for social benefits, growth, connection and competition, more in the rural communities in developing countries.
This study shows appearance of Internet connection in rural areas of Pakistan, and specifically the aim of this research is concerned with a comprehensive examination and analytical procedures on the selection of optimal telecommunications technology infrastructure in Pakistans rural areas.
Literature review was accomplished to investigate the knowledge and understanding in the areas of Multi-Criteria Decision-Making (MCDM) approaches, with particular focus on the analytical decision processes. The findings show that the Analytic Hierarchy Process (AHP) is a powerful decision method which is capable of modeling such a complex problem. An Analytic Hierarchy Process (AHP) method is presented that can be used for the evaluation of alternate technologies in telecommunications. The method is based on pair-wise judgment between various factors that affect the quality of service in a described hierarchical formation.
This research will provide valuable insights for the policy makers from both academics and professionals, on Telecommunications infrastructure providing demonstration and how such rural technology selection decisions can be made within Pakistans rural areas.
Keywords: Analytical Hierarchy Process (AHP), Internet penetration, telecommunication infrastructure, multicriteria decision making (MCDM), technology selection, rural Pakistan.Chapter 1 Introduction 1
1.1 Overview 1
1.2 Research motivation and Objective 3
1.3 Structure of the Thesis 6
Chapter 2 Literature Review on Rural Telecommunication 9
2.1 Characteristics of Rural Areas in Developing Countries 10
2.2 Telecommunication in Rural Areas 12
2.2.1 Telecommunication Rural Applications 16
2.3 Attributes for Rural Telecommunication Infrastructure 19
2.3.1 Attributes for Technical Aspects 22
2.3.2 Attributes for Public Issues 25
2.3.3 Attributes for Cost 28
2.4 Related Literature on Methodology 31
2.4.1 Analytical Hierarchy Process (AHP) 31
2.4.2 Application of AHP in Telecommunication 38
Chapter 3 AHP Model and Access Technologies 40
3.1 Methodology Framework 40
3.2 Structuring AHP Model 41
3.3 Selection of Access Technologies 44
Chapter 4 Configuration and Estimation of Result 51
4.1 Survey and Data 52
4.1.1 AHP Survey 52
4.1.2 Collection of Data 54
4.1.3 Descriptive statistics 56
4.2 Results and Analysis 62
4.2.1 Prioritizing Identified Attributes 62
4.2.2 Synthesis Finding a solution to the problem 63
4.2.3 Participants Preferences for different groups 64
4.2.4 Comparison Perspectives of Groups Preferences 78
4.2.5 Overall Preferences Results (Combined groups) 83
4.3 Analysis and Discussion 85
Chapter 5 Conclusion, Limitations and Future Works 89
5.1 Overall Conclusion 89
5.2 Key finding and Policy Implications 92
5.3 Limitations and Future Work 96
Bibliography 98
Annex 1 - Survey Questionnaire 102
Annex II - AHP Inconsistency of each respondent 114
Abstract in Korean 115Maste
Exploring Relationship among Factors of Motivation and Performance: Analysis from Private Schools in Khyber Pakhtoon Khawa
The aim of this study is to investigate how to employee performance impact on reward in private school. The study also aims to show how to employee improve the performance has in reward system. This study is qualitative in nature and the main theme of this study is to develop hypotheses for future studies. Most of the organizations implement rewards system to increase the job performance and job satisfaction. By reviewing the different finding that the reward and employee performance. The contribution of this paper is to look at how to finding the effective solution of employee performance will be in reward system inter-organizational and school. The study of this paper is exploratory is qualitative study of research. Keywords: Extrinsic rewards; intrinsic rewards; Job Performance
Causative alliance between monetary policy, inflation and inflation rate at economic system in Pakistan
Purpose: This study examine both the monetary policy and inflation are the issues of high interest and importance, and how thus the studying them and their impact on the extension of the macroeconomic variables is a which are concerned for our culture/society.The purpose of this proposal is focusing to identifying the existing connections between the inflation rate and some important macroeconomic indicators /variables and also on the dynamics of inflation at a national level. The main objective of this study is to reveal the causal relation between the inflation rate and the interest rate of the monetary policy and also between the inflation rate and the unemployment rate,Conclusion: There is an inverse statistically significant relation between the inflation rate and the unemployment rate. This indicates that the inflation rate is an effective instrument in preventing the increase of in unemployment. Monetary policy has demonstrated
Methyl 2-oxo-2H-chromene-3-carboxylate
The title compound, C11H8O4, features an almost planar molecule (r.m.s. deviation = 0.033 Å for all non-H atoms). In the crystal, the molecules are linked via C-H...O hydrogen bonds, forming two-dimensional networks lying parallel to (1-21)
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