Karthik Dantu

Autonomous MAV guidance with a lightweight omnidirectional vision sensor

This study describes the design and implementation of several bioinspired algorithms for providing guidance to an ultra-lightweight micro-aerial vehicle (MAV) using a 2.6 g omnidirectional vision sensor. Using this visual guidance system we demonstrate autonomous speed control, centring, and heading stabilisation on board a 30 g MAV flying in a corridor-like environment. In addition to the computation of wide-field optic flow, the comparatively high-resolution omnidirectional imagery provided by this sensor also offers the potential for image-based algorithms such as landmark recognition to be implemented in the future.

Demo: Reptor: Enabling API Virtualization on Android for Platform Openness

This paper proposes a new technique that enables open innovation in mobile platforms. Our technique allows third-party developers to modify, instrument, or extend platform API calls and deploy their modifications seamlessly. The uniqueness of our technique is that it enables modifications completely at the app layer without requiring any platform-level changes. This allows practical openness---third parties can easily distribute their modifications for a platform without the need to update the entire platform. To demonstrate the benefits of our technique, we have developed a prototype on Android called Reptor and used it to instrument real-world apps with novel functionality. Our evaluation in realistic scenarios shows that Reptor has little overhead in performance and energy, and only modest overhead in memory usage that ranges from 0.6% to 10% for the observed worst cases.

UB-ANC emulator: an emulation framework for multi-agent drone networks: demo

Recent interest in hobby aerial vehicles and their applications has seen the emergence of quadrotor designs with various form factors, and development of waypoint-based flight controllers such as APM and Pixhawk. Common to these flight controllers is the use of the Micro Air Vehicle Communications Protocol (MAVLink) that allows the flight controller to communicate with a ground control station. However, it is still challenging to experiment with multiple such aerial vehicles concurrently. To this end, we have developed an open software/hardware platform — the University at Buffalos Airborne Networking and Communications testbed (UB-ANC) — that facilitates rapid development and deployment of multi-drone applications. In this paper, we present the UB-ANC Emulator, an emulation environment to design, implement, and test various applications (missions) involving one or more drones in software, and provides seamless transition to experimentation. We validate the UB-ANC Emulators output against experimental data collected in a mission with three networked drones to demonstrate its feasibility and accuracy, and we demonstrate its scalability up to 100 drones using a simulated “leader-follower” mission.

Making Android Run on Time

Time predictability is difficult to achieve in the complex, layered execution environments that are common in modern embedded devices. We consider the possibility of adopting the Android programming model for a range of embedded applications that extends beyond mobile devices, under the constraint that changes to widely used libraries should be minimized. The challenges we explore include: the interplay between real-time activities and the rest of the system, how to express the timeliness requirements of components, and how well those requirements can be met on stock embedded platforms. We report on the design and implementation of an Android virtual machine with soft-real-time support, and provides experimental data validating feasibility over three case studies.

RAINA: Reliability and Adaptability in Android for Fog Computing

The ubiquity and universality of smartphones make them ideal fog devices to bridge edge devices and the cloud. However, to support a wide range of applications, as well as adhere to the resource constraints presented, the software stack on smart phones needs to be reliable and adaptable. We propose RAINA, an architecture to enable reliability and adaptability in Android. While our work is on Android, our ideas can easily be adapted to other mobile OSs. This article describes our software architecture, systems challenges, application challenges, and methods to address these challenges. We also discuss future work to allow smartphones to truly be at the center of the fog.

Using a Multi-Tasking VM for Mobile Applications

This paper discusses the potential benifits of switching Androids single VM per application runtime environment to a multi-tasking VM environment. A multi-tasking VM is a type of a Java virtual machine with the ability to execute multiple Java applications in one memory space. It does so by isolating the applications to prevent interferences. We argue that using a multi-tasking VM for mobile systems provides better control over application lifecycle management, more flexible memory management, and faster inter-application communication. To support this argument, we discuss a preliminary design, implementation, and evaluation for an alternative to Androids communication mechanism, Binder, and demonstrate the benefits afforded by a multi-tasking VM.

Demo: BlueMountain: An Architecture to Customize Data Management on Mobile Systems

BlueMountain is a system that enables building pluggable data management solutions which can be linked with any Android app at runtime, without requiring any modifications to the Android platform. BlueMountain simplifies the app development, provides flexibility to end users, and works with existing apps.

UB-ANC emulator: An emulation framework for multi-agent drone networks

Recent interest in hobby aerial vehicles and their applications has seen the emergence of quadrotor designs with various form factors, and development of waypoint-based flight controllers such as APM and Pixhawk. Common to these flight controllers is the use of the Micro Air Vehicle Communications Protocol (MAVLink) that allows the flight controller to communicate with a ground control station. However, it is still challenging to experiment with multiple such aerial vehicles concurrently. To this end, we have developed an open software/hardware platform — the University at Buffalos Airborne Networking and Communications testbed (UB-ANC) — that facilitates rapid development and deployment of multi-drone applications. In this paper, we present the UB-ANC Emulator, an emulation environment to design, implement, and test various applications (missions) involving one or more drones in software, and provides seamless transition to experimentation. We validate the UB-ANC Emulators output against experimental data collected in a mission with three networked drones to demonstrate its feasibility and accuracy, and we demonstrate its scalability up to 100 drones using a simulated “leader-follower” mission.

OS-based Resource Accounting for Asynchronous Resource Use in Mobile Systems

One essential functionality of a modern operating system is to accurately account for the resource usage of the underlying hardware. This is especially important for computing systems that operate on battery power, since energy management requires accurately attributing resource uses to processes. However, components such as sensors, actuators and specialized network interfaces are often used in an asynchronous fashion, and makes it difficult to conduct accurate resource accounting. For example, a process that makes a request to a sensor may not be running on the processor for the full duration of the resource usage; and current mechanisms of resource accounting fail to provide accurate accounting for such asynchronous uses. This paper proposes a new mechanism to accurately account for the asynchronous usage of resources in mobile systems. Our insight is that by accurately relating the user requests with kernel requests to device and corresponding device responses, we can accurately attribute resource use to the requesting process. Our prototype implemented in Linux demonstrates that we can account for the usage of asynchronous resources such as GPS and WiFi accurately.

Consistent Cuboid Detection for Semantic Mapping

Building and storing efficient maps is an essentialfeature for long-term autonomy of robots. Modern sensors (such as Kinect) tend to produce a lot of data. However, long-term autonomy requires us to store this information in a succinct manner. One way to reduce dimensionality of information is to attribute semantics. Most indoor objects are cuboidal in nature. We conjecture that cuboids are a suitable semantic feature to attribute to indoor objects for efficient mapping. We adapt a cuboid fitting algorithm previously proposedfor object recognition, for indoor mapping. Our work stems from the observation that landmark detection for mappingrequires consistent detection of those landmarks. We implement several modifications to this cuboid detection algorithm that lead to consistent detection such as emptiness, orientation, surface coverage, distance from edges, and others. We incorporate these in the identification of the cuboid candidates in a scene, as well as an optimization algorithm for finding the best set of consistent cubes to cover a given scene. Our experiments show that in comparison, the set of cuboids detected by our algorithm are at least 50% more consistent based on our metrics.