power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

nowadays in trade and economic issues, prediction is proposed as the most important branch of science. existence of effective variables, caused various sectors of the economic and business executives to prefer having mechanisms which can be used in their decisions. in recent years, several advances have led to various challenges in the science of forecasting. economical managers in various fi...

vocabulary as a major component of language learning has been the object of numerous studies each of which has its own contribution to the field. finding the best way of learning the words deeply and extensively is the common objective of most of those studies. however, one effective way for achieving this goal is somehow neglected in the field. using a variety of activities such as games can r...

abstract: the present study is an attempt to find out cultural exophoric references in iranian high-school elt textbooks and touch stone series to compare the frequency of occurrence of such references in these books. the purpose is to find out which of the series of the books under investigation impose a greater referential burden on efl learners as far as their reading comprehension of the ...

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...

abstract:assume that y is a banach space such that r(y ) ? 2, where r(.) is garc?a-falset’s coefficient. and x is a banach space which can be continuously embedded in y . we prove that x can be renormed to satisfy the weak fixed point property (w-fpp). on the other hand, assume that k is a scattered compact topological space such that k(!) = ? ; and c(k) is the space of all real continuous ...

abstract following innovations in the field of elt, a new topic which has recently attracted a lot of attention is metaphor analysis. although this area of research is still in its infancy in elt, it seems that the idea can shed more light on the puzzle of english language learning and teaching. therefore, the major aim of this study is to analyze language learning and teaching in formal a...

in this thesis, a structured hierarchical methodology based on petri nets is used to introduce a task model for a soccer goalkeeper robot. in real or robot soccer, goalkeeper is an important element which has a key role and challenging features in the game. goalkeeper aims at defending goal from scoring goals by opponent team, actually to prevent the goal from the opponent player’s attacks. thi...

this thesis basically deals with the well-known notion of the bear-invariant of groups, which is the generalization of the schur multiplier of groups. in chapter two, section 2.1, we present an explicit formula for the bear-invariant of a direct product of cyclic groups with respect to nc, c>1. also in section 2.2, we caculate the baer-invatiant of a nilpotent product of cyclic groups wuth resp...