Article history: Received 28 September 2011 Received in revised form 6 January 2012 Accepted 5 February 2012 Available online 20 March 2012

due to their advantages, omni-directional mobile robots have found many applications especially in robotic soccer competitions. however, omni directional navigation system, omni-vision system and kicking mechanism in such mobile robots have not ever been combined. this situation brings the idea of a robot with no head direction into existence, a comprehensive omni directional mobile robot. such...

The paper presents a new algorithm, its implementation, and results of extensive testing, for a microprocessor-based lowimpedance busbar relay. For increased security, the presented technique combines percent differential and current directional protection principles. The directional (phase comparison) principle does not require a voltage signal as it responds to relative directions of the curr...

Directional long drilling on the roof is an effective gas control measure in goaf, but there little research stability of surrounding rock. In this study, geological conditions #4 coal seam Tingnan Coal Mine, Shaanxi Province, China taken as application background, and deformation characteristics boreholes under four typical rock were first analyzed based Universal Distinct Element Code (UDEC) ...

RNA stability control and degradation are employed by cells to control gene expression and to adjust the level of protein synthesis in response to physiological needs. In all domains of life, mRNA decay can commence in the 5'-3' as well as in the 3'-5'-direction. Consequently, mechanisms are in place conferring protection on mRNAs at both ends. Upon deprotection, dedicated enzymes/enzyme comple...

In design and analysis, standard references assume the pedestrian flow as unidirectional. In reality however, pedestrian flow is usually bi-directional. The main question pursued in this paper is that whether the main characteristics of pedestrian flow the same under uni- and bi-directional conditions. In order to achieve this goal, effect of bi-directional stream is inv...

The dogleg severity is one of the most important parameters in directional drilling. Improvement of these indicators actually means choosing the best conditions for the directional drilling in order to reach the target point. Selection of high levels of the dogleg severity actually means minimizing well trajectory, but on the other hand, increases fatigue in drill string, increases torque and d...