In this paper, a new antenna is presented which has an application in cellular telecommunication systems. The designed antenna works at the frequency range of 1900-2600 MHz which is able to cover 2G, 3G and 4G (LTE) services of the cellular telecommunication. In this paper, the micro-strip structure has been used to design the antenna. The shape of the patches is triangular where a peripheral r...

introduction: preserving the apical root structure during cleaning and shaping of the canal has always been a challenge in endodontics particularly when the root canals are curved. the purpose of this in vitro study was to compare the apical transportation induced by the reciproc and biorace rotary systems in preparing the mesiobuccal root canal of the human maxillary molars. materials and meth...

A telecommunication system like an ISDN network comprises a great variety of software components. It includes software for switches, the terminal equipment (like a simple telephone) but also for the management of resources and the provision of high level services like time dependent call forwarding. Software for telecommunication systems like other software must be fast, robust and easy to main...

The popularity of the great variety of Internet usage brings about a significant growth of the data traffic in telecommunication network. Data transmission efficiency will be challenged under the premise of current network capacity and data flow control mechanisms. In addition to increasing financial investment to expand the network capacity, improving the existing techniques are more rational ...

  Selection of appropriate infrastructure transportation projects such as highways, plays an important role in promotion of transportation systems. Usually in evaluation of transportation projects, because of lack of information or due to long time and high expenditures needed for gathering information, different effective factors are ignored. Thus, in this research, regarding multi criteria na...

Increasing pressures caused by negative consequences of transportation and traffic problems in major cities, have resulted many attempts towards improvement of planning and management of transportation systems, according to sustainability objectives. In this paper, a comprehensive model is developed using a system dynamics approach to evaluate sustainable urban transportation. This model includ...

background and goal: burn is an irreparable event, which results in numerous physical, psychological, social, and economic complications. the burned patients should be merely treated in a professional burn center due to vast clinical range of these patients. since, a percentage of mortality in burned patients is for the patients’ transportation from other centers; this study has aimed to invest...