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Security is a one of the most important factors of urban environments. Therefore, the necessity of security in urban spaces has caused the emersion of authentic theories like defensible spaces and crime prevention through environment design (CPTED) . In this paper, various literatures related to defensible space theories have been reviewed and the related keywords have been defined. Then the role of defensible urban spaces as a social capital in reduction of urban crimes is determined. Finally, the condition of defensible spaces in ITC with an emphasis on Isfahan city has been studied. The research methodology is based on the analysis of data and documents collected through field survey. The research results justify the precedence of defensible spaces – in design and planning- at shaping the Iranian historical cities. Secure and defensible spaces, which support social capital concept under public surveillance and collective responsibility, work as an important aspect in reducing crimes and stability of urban security. Ke

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Nowadays, the spectrum is becoming more
and more scarce because of not only the demand increase
for wireless services and applications but also inflexible and
rigid spectrum allocation policies. A promising solution to
overcome this challenge is to exploit spectrum holes for
secondary users in cognitive radio. Taking advantage of
cognitive radio and dynamic spectrum access improves the
efficiency of spectrum utilization as it allows secondary
users to exploit the available frequency bandwidth. In
an opportunistic spectrum access scenario, the secondary
users can only utilize the frequency bandwidth when the
primary user is inactive. In this paper, we assume that
secondary users exploit the available frequency bandwidth
using opportunistic spectrum access approach. As a result,
one may model the available bandwidth to the secondary
users as a random process taking value of 0 or 1. In
this paper, we investigate the effects of Rayleigh fading
environment on the capacity of AWGN point-to-point
channel. Afterwards, we also go beyond point to point
channels and analyze Multiple Access Channels. More
precisely, we derive the closed form expression of ergodic
capacity region of Multiple Access fading Channel with
two independent sources. To the best of our knowledge,
no prior work has investigated the ergodic capacity region
of Multiple Access Channel under Rayleigh fading
with the aforementioned approach. Numerical analysis are
conducted to validate our theoretical results. Interestingly,
numerical results indicate that, against the common sense,
capacity of Rayleigh fading environment channels are
higher than deterministic ones in Gaussian point-to-point
channels.
 

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In order to utilize robots for industrial tasks, designing a suitable path is necessary.Executing the path by the robot in the presence of obstacles, makes the path planning task a difficult one. In addition, path planning is a time consuming task and needs expertise to define certain path for each industrial job. In this paper, uses Jerk-minimum method, B-Spline curves, via-point, and obstacle avoidance algorithm to automatically generate a suitable and safe path for a simulated 7 degrees of freedom industrial manipulator.A user determines via-points for robot trajectory using a Kinect sensor,then a combination of Jerk-minimum method, B-Spline curves, a path is generated. This path is checked by an obstacle avoidance algorithm,and a final path is generated. The obstacle avoidance algorithm uses the inverse kinematic equation of the robot to modify the robot trajectory. One of the advantages of the proposed method is both to facilitate trajectory planning for the user and to create a smooth trajectory for the robotic arm.

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Importance of security and sense of peace is a one of the most important factors of urban environment. Therefore, the necessity of security in urban spaces has caused the emergence of authentic theories like Defensible Spaces and Crime Prevention through Environment Design (CPTED)*. In this paper, various literatures related to defensible space theories have been reviewed and the related keywords have been defined. Then, the role of defensible urban spaces as a social capital in the reduction of urban crimes is examined. Further, condition of defensible spaces in traditional Iranian cities has been studied with reference to the city of Isfahan. The research method is based on data and documents collected through field survey.The conclusion justifies the precedent of defensible space, in design and planning, as well as shaping historical cities. Safe and secure spaces which support social capital concept, under public surveillance and collective responsibility, works as an important aspect in reducing crimes hence; bringing about a state of stable urban security.