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 ...

this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitud...

the present study was carried on to investigate the use of face-keeping strategies in reaction to complaints by male and female in two different cultures, persian and american english. to see if apology strategies are affected by cultural, contextual preferences and gender of interlocutors in two distinct languages of persian and american english. the hypotheses to be tested were 1) ifids, acce...

the present thesis is going to investigate the theme of despair, darkness and pesimism in philip larkins poetry. larkin is a british poet whose poems were composed in the dark and gloomy years of postwar. so, his poetry contains and reflects the same darkness and despair of his age. a good number of poems form different collections of his poetry are chosen and will be analyzed in the light of t...

the purpose of this study is identifying effective factors which make customers shop online in iran and investigating the importance of discovered factors in online customers’ decision. in the identifying phase, to discover the factors affecting online shopping behavior of customers in iran, the derived reference model summarizing antecedents of online shopping proposed by change et al. was us...

increasing academic and professional language demands around the world are not a deniable fact. the purpose of this study was to investigate english language needs and communication needs of the chemistry students at master and ph.d. levels at the iranian universities. in this research, different methods were used including un-structured interview, structured interview, and two sets of question...

the speech act of disagreement has been one of the speech acts that has received the least attention in the field of pragmatics. this study investigates the ways power relations, social distance, formality of the context, gender, and language proficiency (for efl learners) influence disagreement and politeness strategies. the participants of the study were 200 male and female native persian s...

Increasing soil contamination by chemicals has become an issue of increasing environmental concern. Leaching of chemicals into and through the vadose zone creats serious problems due to the contamination of the soil matrix, soil solution and groundwater. Therefore, in order to study the effect of the preferential flow, macropores and organic matter on mobility and leaching of the metals such as...