Kiryong Ha

Towards wearable cognitive assistance

We describe the architecture and prototype implementation of an assistive system based on Google Glass devices for users in cognitive decline. It combines the first-person image capture and sensing capabilities of Glass with remote processing to perform real-time scene interpretation. The system architecture is multi-tiered. It offers tight end-to-end latency bounds on compute-intensive operations, while addressing concerns such as limited battery capacity and limited processing capability of wearable devices. The system gracefully degrades services in the face of network failures and unavailability of distant architectural tiers.

Edge Analytics in the Internet of Things

High-data-rate sensors, such as video cameras, are becoming ubiquitous in the Internet of Things. This article describes GigaSight, an Internet-scale repository of crowd-sourced video content, with strong enforcement of privacy preferences and access controls. The GigaSight architecture is a federated system of VM-based cloudlets that perform video analytics at the edge of the Internet, thus reducing the demand for ingress bandwidth into the cloud. Denaturing, which is an owner-specific reduction in fidelity of video content to preserve privacy, is one form of analytics on cloudlets. Content-based indexing for search is another form of cloudlet-based analytics. This article is part of a special issue on smart spaces.

Scalable crowd-sourcing of video from mobile devices

We propose a scalable Internet system for continuous collection of crowd-sourced video from devices such as Google Glass. Our hybrid cloud architecture, GigaSight, is effectively a Content Delivery Network (CDN) in reverse. It achieves scalability by decentralizing the collection infrastructure using cloudlets based on virtual machines~(VMs). Based on time, location, and content, privacy sensitive information is automatically removed from the video. This process, which we refer to as denaturing, is executed in a user-specific VM on the cloudlet. Users can perform content-based searches on the total catalog of denatured videos. Our experiments reveal the bottlenecks for video upload, denaturing, indexing, and content-based search. They also provide insight on how parameters such as frame rate and resolution impact scalability.

The Role of Cloudlets in Hostile Environments

The convergence of mobile computing and cloud computing is predicated on a reliable, high-bandwidth end-to-end network. This basic requirement is hard to guarantee in hostile environments such as military operations and disaster recovery. In this article, the authors examine how VM-based cloudlets that are located in close proximity to associated mobile devices can overcome this challenge. This article is part of a special issue on the edge of the cloud.

Just-in-time provisioning for cyber foraging

Cloud offload is an important technique in mobile computing. VM-based cloudlets have been proposed as offload sites for the resource-intensive and latency-sensitive computations typically associated with mobile multimedia applications. Since cloud offload relies on precisely-configured back-end software, it is difficult to support at global scale across cloudlets in multiple domains. To address this problem, we describe just-in-time (JIT) provisioning of cloudlets under the control of an associated mobile device. Using a suite of five representative mobile applications, we demonstrate a prototype system that is capable of provisioning a cloudlet with a non-trivial VM image in 10 seconds. This speed is achieved through dynamic VM synthesis and a series of optimizations to aggressively reduce transfer costs and startup latency.

Lowering the barriers to large-scale mobile crowdsensing

Mobile crowdsensing is becoming a vital technique for environment monitoring, infrastructure management, and social computing. However, deploying mobile crowdsensing applications in large-scale environments is not a trivial task. It creates a tremendous burden on application developers as well as mobile users. In this paper we try to reveal the barriers hampering the scale-up of mobile crowdsensing applications, and to offer our initial thoughts on the potential solutions to lowering the barriers.

The Impact of Mobile Multimedia Applications on Data Center Consolidation

The convergence of mobile computing and cloud computing enables new multimedia applications that are both resource-intensive and interaction-intensive. For these applications, end-to-end network bandwidth and latency matter greatly when cloud resources are used to augment the computational power and battery life of a mobile device. We first present quantitative evidence that this crucial design consideration to meet interactive performance criteria limits data center consolidation. We then describe an architectural solution that is a seamless extension of todays cloud computing infrastructure.

A Reference Architecture for Mobile Code Offload in Hostile Environments

Handheld mobile technology can help disaster relief workers and soldiers in the field with tasks such as speech and image recognition, natural language processing, decision-making, and mission planning. However, these applications are computation-intensive, take a heavy toll on battery power, and often rely on good connectivity to networks, limiting their practical usefulness in a crisis. This paper presents a reference architecture for mobile devices that overcomes these limitations by exploiting cloudlets - VM-based code offload elements that are in single-hop proximity to mobile devices.

Quantifying the Impact of Edge Computing on Mobile Applications

Computational offloading services at the edge of the Internet for mobile devices are becoming a reality. Using a wide range of mobile applications, we explore how such infrastructure improves latency and energy consumption relative to the cloud. We present experimental results from WiFi and 4G LTE networks that confirm substantial wins from edge computing for highly interactive mobile applications.

The Case for Offload Shaping

When offloading computation from a mobile device, we show that it can pay to perform additional on-device work in order to reduce the offloading workload. We call this offload shaping, and demonstrate its application at many different levels of abstraction using a variety of techniques. We show that offload shaping can produce significant reduction in resource demand, with little loss of application-level fidelity.