Implementation and evaluation of fast mobile vnc systems

Abstract

VNC (virtual network computing) is a popular tool for sharing an application, allowing users to access graphic displays remotely. In mobile VNC systems, it has been challenging to increase screen update rate by fast screen image encoding. In this paper, we implement a prototype system for mobile VNC, and several works are done for improving screen update rate. At first, a number of video encoders are integrated into a prototype system, and we investigate what is the most suitable codec for mobile VNC. The existing RFB protocol is extended straightforwardly to integrate video codecs. Next, the overall system architecture is modified from serial operation to parallel. Finally, we propose a modified region coding to further reduce the encoding time of screen images. The proposed methods are implemented into our prototype mobile VNC system, and practical performances are widely evaluated. We report that JPEG is the most suitable for mobile VNC in terms of both complexity and compression ratio. In addition, the proposed modified region coding can decrease encoding time, and consequently increase screen update rate 1 .

Investigating the pedagogies of screen‐sharing in contemporary learning environments—A mixed methods analysis

“…Searches of patents reveal emerging forms of the technology in the 1990s (see, e.g., Epard et al, 1993) and early 2000s (Lu et al, 2002). By the mid-2000s, however, the concept of web-enabled screen-sharing had In spite of screen-sharing technologies being evident in enterprise, education and consumer technology products for some considerable time, research has mainly considered technical aspects and their practical benefits (Ishida et al, 2020;Keun-Woo Lim et al, 2018;Ko et al, 2012;Miao et al, 2016;Pan et al, 2013;Tendeloo & Vangheluwe, 2018). By contrast, educational research directly focusing on the impact and pedagogies of screen-sharing has largely been lacking.…”

ROS Based Multimode Control of Wheeled Robot

“…The torque for the wheels comes from the DC motors τ=r*F (4) τ=r*m*g*μs (5) For a dc motor with constant input voltage τ=KT*id (6) KT*id =m*g*μs (7) id=m*g*μs /KT (8) Here, id is the minimum current requirement for the bot.…”

“…In [2] the voice command of eight languages is used for security system where as the app designed in this research work can take input command of many languages and can control the bot accordingly similar to that of [3]. Mobile control had been achieved using the VNC viewer by reducing its screen encoding time using the technique in [4]. IoT ASTESJ ISSN: 2415-6698 control method is similar to [5] but instead of an WIFI module and raspberry pi, we used NodeMcu which can both receive WIFI signal and control the robot.…”