In this paper, we propose Nutrilyzer, a novel mobile sensing system for characterizing the nutrients and detecting adulterants in liquid food with the photoacoustic effect. By listening to the sound of the intensity modulated light or electromagnetic wave with different wavelengths, our mobile photoacoustic sensing system captures unique spectra produced by the transmitted and scattered light while passing through various liquid food. As different liquid foods with different chemical compositions yield uniquely different spectral signatures, Nutrilyzer's signal processing and machine learning algorithm learn to map the photoacoustic signature to various liquid food characteristics including nutrients and adulterants. We evaluated Nutrilyzer for milk nutrient prediction (i.e., milk protein) and milk adulterant detection. We have also explored Nutrilyzer for alcohol concentration prediction. The Nutrilyzer mobile system consists of an array of 16 LEDs in ultraviolet, visible and near-infrared region, two piezoelectric sensors and an ARM microcontroller unit, which are designed and fabricated in a printed circuit board and a 3D printed photoacoustic housing.

The scale and expense of modern data centers motivates running them as efficiently as possible. This paper explores how virtualized data center performance can be improved when network traffic and topology data informs VM placement. Our practical heuristics, tested on network-heavy, scale-out workloads in an 80 server cluster, improve overall performance by up to 70% compared to random placement in a multi-tenant configuration.

Many data-intensive scientific analysis techniques require global domain traversal, which over the years has been a bottleneck for efficient parallelization across distributed-memory architectures. Inspired by MapReduce and other simplified parallel programming approaches, we have designed DStep, a flexible system that greatly simplifies efficient parallelization of domain traversal techniques at scale. In order to deliver both simplicity to users as well as scalability on HPC platforms, we introduce a novel two-tiered communication architecture for managing and exploiting asynchronous communication loads. We also integrate our design with advanced parallel I/O techniques that operate directly on native simulation output. We demonstrate DStep by performing teleconnection analysis across ensemble runs of terascale atmospheric CO2 and climate data, and we show scalability results on up to 65,536 IBM BlueGene/P cores.

Many data centers extensively use virtual machines (VMs), which provide the flexibility to move workload among physical servers. VMs can be placed to maximize application performance, power efficiency, or even fault tolerance. However, VMs are typically repositioned without considering network topology, congestion, or traffic routes.

Stochastic self-reconfiguring robots are modular robots that possess the ability to autonomously change the arrangement of their modules and do so through the use of non-deterministic processes. We present a concept for a robotic system in which the stochastic behavior of turbulent flow in a chamber is used during assembly and disassembly operations. The thermorheological properties of Pluronic®are used to implement flow routing for controlling the assembly process. This is the first use of thermorheological valving in three dimensions. A novel reversible module connection mechanism using a low melting point alloy which is soldered in a fluid environment is presented. Together with our approach to self-alignment, these are the innovations required to allow scalable self-directed assembly in three dimensions.

In this demo, we present Ripcord, a modular platform for rapidly prototyping scale-out data center networks. Ripcord enables researchers to build and evaluate new network features and topologies, using only commercially available hardware and open-source software. The Ripcord demo will show three examples of custom network functions, operating together, on top of a 160-node cluster. The first is a routing engine that isolates classes of traffic. The second is a dynamic network manager than adjusts links and switch power states to reduce energy. The third is a statistics aggregator that supports network health monitoring and automatic alerts. The demo will be interactive, with a visualization of live parameters for each link and switch, such as bandwidth, drops, and power status, as well a control panel to modify the traffic load. We feel that an interactive demo is the best way to introduce the research community to Ripcord and get their feedback.

Modular robotic systems typically assemble using deterministic processes where modules are directly placed into their target position. By contrast, stochastic modular robots take advantage of ambient environmental energy for the transportation and delivery of robot components to target locations, thus offering potential scalability. The inability to precisely predict component availability and assembly rates is a key challenge for planning in such environments. Here, we describe a computationally efficient simulator to model a modular robotic system that assembles in a stochastic fluid environment. This simulator allows us to address the challenge of planning for stochastic assembly by testing a series of potential strategies. We first calibrate the simulator using both high-fidelity computational fluid-dynamics simulations and physical experiments. We then use this simulator to study the effects of various system parameters and assembly strategies on the speed and accuracy of assembly of topologically different target structures.

We describe the implementation of an OpenFlow Switch on the NetFPGA platform. OpenFlow is a way to deploy experimental or new protocols in networks that carry production traffic. An OpenFlow network consists of simple flow-based switches in the datapath, with a remote controller to manage several switches. In practice, OpenFlow is most often added as a feature to an existing Ethernet switch, IPv4 router or wireless access point. An OpenFlow-enabled device has an internal flow-table and a standardized interface to add and remove flow entries remotely.Our implementation of OpenFlow on the NetFPGA is one of several reference implementations we have implemented on different platforms. Our simple OpenFlow implementation is capable of running at line-rate and handling all the traffic that is going through the Stanford Electrical Engineering and Computer Science building. We compare our implementation's complexity to a basic IPv4 router implementation and a basic Ethernet learning switch implementation. We describe the OpenFlow deployment into the Stanford campus and the Internet2 backbone.

Robots must be designed with consideration for reconfiguring body pose during operation if they are to address more challenging environments. Researchers have mostly relied on static stability methods to monitor the possibility of rollover in stationary or slow moving vehicles. However, little research in dynamic stability is being conducted for robots capable of reconfiguring their pose to overcome obstacles encountered in challenging terrains. A multi-degree-of-freedom robot with the capability to vary its center of gravity is discussed in this paper. It is designed to improve mobility over rough terrain and is used in this paper as an example to address one aspect of dynamic stability. A complete understanding of the dynamic behaviour of a multiple degree of freedom robot in unstructured terrain is a difficult problem to solve. It is too complex to solve completely and therefore a reduced aspect of the problem is addressed. The robot will only have the ability to vary its center of gravity in the plane parallel to its direction of forward motion. In addition the robot will only move on flat terrain and encounter an immovable linear step feature. The result of the research is that once the center of gravity is specified by selection of robot body pose, and a maximum obstacle considered, platform stability can be ensured with a maximum allowable velocity. In other words, a maximum allowable velocity of the robot is governed by the position of the center of gravity relative to the wheel in contact with the linear step feature. If the robot is traveling below the predetermined maximum velocity then the robot is guaranteed to remain upright.

This paper presents the libdrdc data standards library containing internal nomenclature, definitions, units of measure, coordinate reference frames, and representations for use in autonomous systems research. This library is a configurable, portable C / C++ / object oriented C library developed to be independent of software middleware, system architecture, processor, or operating system. It is designed to use the automatically-tuned linear algebra suite (ATLAS) and basic linear algebra suite (BLAS) and port to firmware and software. The library goal is to unify data collection and representation for various systems and communication protocols and to provide a common application binary interface (ABI) for research projects at all scales. The library supports multi-platform development and currently works on Windows, Unix, GNU/Linux, and Real-Time Executive for Multiprocessor Systems (RTEMS). This library is available online under Lesser Gnu Public License (LGPL) version 2.1 license.