Ken Lutz

A prototype user interface for a mobile multimedia terminal

We have shown a prototype user interface for the InfoPad, a portable terminal with multi-modal input and multimedia output. We believe that many of the people who could benefit from inexpensive, portable, networked terminals are not computer experts, and we are therefore designing the InfoPad and its user interface to be more like a notebook than a workstation. The InfoPad’s main features are: ● Portabilityy ●Continuous network connectivity using a highbandwidth radio link ● Pen input with handwriting recognition ● Audio input with speech recognition ● Full-motion video playback with synchronized audio The InfoPad’s unique input and output characteristics offer challenges and opportunities for user interface design. We are prototyping applications and user interfaces to explore how handwriting and voice recognition may best be used together. We believe that the lessons we will learn can be applied to other multi-modal platforms.

Performance and design evaluation of the RAID-II storage server

RAID-II is a high-bandwidth, network-attached storage server designed and implemented at the University of California at Berkeley. In this paper, we measure the performance of RAID-II and evaluate various architectural decisions made during the design process. We first measure the end-to-end performance of the system to be approximately 20 MB/s for both disk array reads and writes. We then perform a bottleneck analysis by examining the performance of each individual subsystem and conclude that the disk subsystem limits performance. By adding a custom interconnect board with a high-speed memory and bus system and parity engine, we are able to achieve a performance speedup of 8 to 15 over a comparative system using only off-the-shelf hardware.

Workloads of the Future

Along with changing technologies and design techniques, target applications span a wide range: from large-scale computing to personal services and perceptual interfaces. The authors of this article characterize these workloads of the future and argue for a new set of benchmarks to guide the exploration and optimization of future systems.

The impact of flexible loads in increasingly renewable grids

We develop a flexible and responsive electrical load in the form of domestic refrigerators augmented with a thermal storage system, a wireless sensor network for monitoring and actuation, and a controller that enables response to external controls. Using this, we investigate the potential of such loads for two applications: price-responsive demand and supply-following. Our prototype shows that with a 13% increase in refrigerator electricity consumption, we are able to avoid electricity consumption for over six hours. We employ a methodology for creating models of electricity grids with high renewables penetration, and study the effects of deploying variable populations of flexible energy storage refrigerators in grids at variable levels of renewables penetration. Our results show that our prototype can respond to time-of-use price tariffs to reduce summer refrigeration electricity cost by up to 13% on the consumer side, while substantially reducing the capital investment on the utility side by smoothing the peak. At higher levels of renewables penetration, with 20% of refrigerators in California adopting this technology and acting as supply-following electricity loads, flexible refrigerators can shave off 5% of peak capacity needs. The approach naturally extends to similar applications in thermal management of buildings and would operate in concert with other load management efforts such as smart vehicle charging.

Design of wireless portable systems

The InfoPad project explores the infrastructure and devices required for portable wireless access to the national information infrastructure. The InfoPad model emphasizes high-bandwidth wireless connectivity and moves the computing power of the portable device into the backbone network, where we can provide not only full internet access, but increased computing power as well. By concentrating on I/O for the pad we reduce its cost, weight and power requirements, and increase the effective bandwidth through the greater error tolerance of I/O traffic such as video. We describe the InfoPad model, its infrastructure, and the results of the first prototype. This prototype proved the feasibility of the basic model and developed key technologies such as low-power design methodology and protocols for wireless connections. We also discuss the next generation InfoPad and our future plans.

Toward a Global Data Infrastructure

The Internet of Things (IoT) represents a new class of applications that can benefit from cloud infrastructure. However, directly connecting smart devices to the cloud has multiple disadvantages and is unlikely to keep up with the growing speed of the IoT or the diverse needs of IoT applications. Here, the authors argue that fundamental IoT properties prevent the current approach from scaling. Whats missing is a well-architected system extending cloud functionality and providing seamless interplay among heterogeneous components closer to the edge in the IoT space. Raising the level of abstraction to a data-centric design -- focused around the distribution, preservation, and protection of information -- better matches the IoT. To address such problems with the cloud-centric architecture, the authors present their early work on a distributed platform, the Global Data Plane.

Flexible loads in future energy networks

We develop a vignette of an information-rich energy network with flexible and responsive electrical loads in the form of a domestic refrigerator augmented with a thermal storage system and a supply-following controller that responds to the availability of fluctuating renewable sources. We fully characterize our prototype thermal storage-enhanced refrigerator. Using this, we investigate the behavior of a network of such loads at statewide scale in the context of a dynamic model of deep penetration of renewable sources. Our results show that with 10% penetration of thermal storage across refrigeration and freezer load on the California electricity grid, peak fossil fuel load can be reduced by nearly a gigawatt. The approach naturally extends to similar applications in thermal management of buildings and would operate in concert with smart vehicle charging.