Soraya Ghiasi

Generic web-based teleoperations architecture: details and experience

Teleoperation of remote devices on the World Wide Web is becoming more common and feasible. Prices on devices ranging from digital cameras to LEGO RCXs(tm) have dropped, making them available to a much wider audience. Increasing availability of remotely operable devices removes one barrier to ubiquitous telepresence, but leaves others intact. One of the remaining barriers is the need for a user to develop and deploy an end-to-end solution for device manipulation. The goal of our research is to reduce this barrier by making a flexible end-to-end solution accessible to a wide audience of potential Web device developers.

A Comparison of Two Architectural Power Models

Reducing power, on both a per cycle basis and as the total energy used over the lifetime of an application, has become more important as small and embedded devices become increasingly available. A variety of techniques are available to reduce power, but it is difficult to quantify the benefits of these techniques early in the system design phase when processor architecture is being defined. Accurate tools that allow for exploration of the design space during this phase are crucial. This paper describes our experience with two such tools, the Cai-Lim power model and Wattch, which have been made available to the computer architecture community over the past year. We focus on how the models are constructed, the granularity of activity revealed by the models, the ability to understand why particular power results are obtained and the accuracy of the models. We raise concerns about detailed simulations where the power model, the simulator model and the desired architecture to be simulated differ and the validity of data obtained in such situations.

VIPR and the Visual Programming Challenge

Abstract The Visual Programming Challenge (VPC) provides a framework for exploring visual programming language issues in a quasi-real-time environment and for comparing competing languages. VIPR is an attempt to bring the traditional strengths of textual imperative languages to a visual programming language. It leverages these strengths to make use of well-understood design and abstraction methodologies while providing additional visual features, such as explicit representations, contextual information, and execution animation. VIPR uses these strengths and features to address the quasi-real-time problem posed by the VPC, whose requirements include interaction with the low-level vehicle manipulation code, map exploration and display, as well as additional requirements such as flexibility of solution and performance demands. Our solution does not directly address pedagogical issues or the value of VIPRs simple graphical semantics. It did point out weaknesses with VIPRs approach to solving the scalability problem in visual programming languages.

CPU packing for multiprocessor power reduction

Power and cooling considerations have moved to the forefront of modern system design. The restrictions placed upon systems by power and cooling requirements have focused much research on a variety of techniques to reduce maximum power and leakage. Simultaneously, efforts are being made to adapt microarchitectural features to the current needs of an application. We focus instead on adapting large scale resources to the current needs of a server farm. We study the efficacy of powering on and off CPUs in symmetric multiprocessors (SMP). We develop a number of different predictive and reactive techniques for identifying when cores should have their state altered. We present results for these policies and find a hybrid policy presents a reasonable balance between the time necessary to predict future needs and the accuracy of these predictions. It maintains 97% of the original system performance while reducing the energy per web interaction by 25%.

Wireless communications with mobile devices in a web-based teleoperations environment

Deploying robotic devices for Web-based teleoperation is currently the domain of academic researchers, commercial enterprises and a small group of dedicated hobbyists. Before more people can deploy their own devices, a number of difficult issues need to be addressed. In previous work, we presented a reusable framework for Web-based teleoperation of robotic devices and attempted to address some of these deployment issues. However, a number of problems still remain, including how to support communication with a mobile remote device. Any remotely operated device requires some form of communication channel to its operator. In many current systems, this communications channel is composed of a long-haul network connection as well as a short-range connection between the device and a base unit. For a mobile device, one traditional solution for this short-range connection has been tethered operation. Tethered operation imposes a number of undesirable limitations on mobile devices however, so many researchers have turned to wireless communication as an alternative. As both the monetary and power costs associated with wireless communications continue to decrease, it becomes more viable as a general solution to the problem of providing communication between a base unit and a mobile device. We present an overview of the current state of the art in commercially available wireless communications and its implications for Web-based teleoperations. We also discuss how the requirements and implementation of our existing reusable framework will be modi ed in response to the new requirements imposed by wireless communication.

Reusable framework for Web-based teleoperation

The advent of the WWW presents an opportunity for a wide audience to make use of telemanipulation. Unfortunately, current efforts in Web-based telemanipulation are primarily undertaken by individual groups and lead to a plethora of specific solutions, instead of a general, reusable framework. Because of this, any groups seeking to enter into this field must spend a large amount of time building the interfaces necessary for remote monitoring and manipulation. Our proposed solution to this problem is to build a general framework of Java-based components that allow researchers to focus on their particular applications instead of building the infrastructure for Web interaction themselves. These components only require researchers to build an interface to our framework, instead of implementing a complete end-to-end solutions. This framework is designed to enable the manipulation of simple to medium complexity devices via the WWW. Example application domains include small robotic vehicles and robotic arms.