---

Aims: The purpose of this study is to investigate the role of vegetation in reducing nuisance wind speed on the Imam Street sidewalk. Imam Street is one of the main arteries in Tabriz, and the nuisance wind speed on its sidewalks disturbs the climate comfort for pedestrians, especially during the cold season.

Methods: A descriptive-analytical method is used in this study, and numerical simulations are performed using Dlubal RWIND 2.02 to evaluate the wind flow for the current condition and the proposed alternatives. In this context, the effect of vegetation height, spacing and arrangement (with tree bench) as independent variables on wind speed at pedestrian height as dependent variable was investigated. Spearman correlation test is used to evaluate the relationship between variables.

Findings: The studies have shown that trees with a height of 4 meters, distributed at a distance of 5 meters according to the pattern 1, can reduce the flow velocity on the pedestrian level by 52%.

Conclusion: The results show that the implementation of vegetation in appropriate spacing and pattern can significantly reduce wind speed. Placing tree benches on the sidewalk changes the airflow toward the street and reduces wind speed at the pedestrian level.
 

---

Sliding mode control technique is one of the well-recognized non-linear control methods. This method has an advantage like robustness against uncertainties. However, chattering phenomenon constraints the performance of closed loop system. To increase its efficiency, a fuzzy compensator is used along with this method. The fuzzy compensator weights are updated by using adaptive rules. The adaptation rate acts as a controlling coefficient. Therefore, the bigger amount of it increases the adaptation speed of weights which leads to the improvement of closed loop system performance. As a result, the probability of instability of closed loop system increases, too. In this study, it has been proposed to use a parallel fuzzy system along with the main fuzzy system in order to control its weights' adaptation. Moreover, a non-linear model of the electro-hydraulic system has been introduced as a case study. Finally, the performance of closed loop system and the efficiency of the proposed methods have been investigated by using numerical simulations.

---

Robotic arms are widely used for 2D desktop applications. In this paper, a new mechanism for a planar robotic arm is presented. In addition to having the benefits of both series of parallel robots, the proposed mechanism also eliminates the disadvantages of both categories. The arm made on the same side as the parallel arms has rigidity, strength and precision, and other positive features of the parallel arms, and on the other hand, like the serial arms, due to the lack of singular points inside the workspace, has a large, symmetrical and also be able to move continuously in the entire workspace. The kinematics relations for the arm are derived, and a controller based on AVR microcontroller & computer for the arm are introduced. The results indicate an improvement in arm performance and the removal of singular points from within the workspace.