Now showing items 1-20 of 597

    • Evaluating Multihop Mobile Wireless Networks with Controllable Node Sparsity or Density 

      Amiri, Keyvan (2015-12-04)
      Simulation is the most widely used tool for evaluating the performance of multihop mobile wireless networks, yet such simulation has so far been limited due to the lack of sufficient wireless mobility models for creating a wide range of different types of network scenarios of mobile nodes moving about for use in protocol simulation. For example, the ...
    • Inference by Reparameterization using Neural Population Codes 

      Vasudeva Raju, Rajkumar (2015-12-04)
      Behavioral experiments on humans and animals suggest that the brain performs probabilistic inference to interpret its environment. Here we present a general-purpose, biologically plausible implementation of approximate inference based on Probabilistic Population Codes (PPCs). PPCs are distributed neural representations of probability distributions ...
    • Nonlinear neural codes 

      Yang, Qianli (2015-12-03)
      Most natural task-relevant variables are encoded in the early sensory cortex in a form that can only be decoded nonlinearly. Yet despite being a core function of the brain, nonlinear population codes are rarely studied and poorly understood. Interestingly, the most relevant existing quantitative model of nonlinear codes is inconsistent with known ...
    • Rethinking Image Compression for the Object Detection Task 

      Barua, Souptik (2015-12-03)
      Traditionally, image compression algorithms, such as JPEG, have been designed for human viewers' satisfaction. Increasingly however, more and more images are being viewed by computers, for performing computer vision tasks such as object detection. Image compression and object detection have largely been independent areas of research so far. However, ...
    • MIMO Broadcast Channels with Full-duplex feedback 

      Du, Xu (2015-12-03)
      In this thesis, I utilize full-duplex radios to increase the downlink spectral efficiency of MIMO broadcast channels by proposing a sequential beamforming strategy. In current half-duplex multiuser MIMO systems, non-trivial time resources is devoted into the collection of channel state information (CSI). In sequential beamforming strategy, instead ...
    • Full-duplex Wireless with Large Antenna Arrays 

      Everett, Evan Jackson (2015-12-03)
      To meet the growing demand for wireless data, base stations with very large antenna arrays are being deployed in order to serve multiple users simultaneously. Concurrently, there is growing interest in full-duplex operation. The challenge to full-duplex is suppressing the high-powered self-interference caused by transmitting and receiving at the same ...
    • GPU Accelerated Reconfigurable Detector and Precoder for Massive MIMO SDR Systems 

      Li, Kaipeng (2015-12-02)
      We present a reconfigurable GPU-based unified detector and precoder for massive MIMO software-defined radio systems. To enable high throughput, we implement the linear minimum mean square error detector/precoder and further reduce the algorithm complexity by numerical approximation without sacrificing the error-rate performance. For efficient GPU ...
    • A Resource-Aware Streaming-based Framework for Big Data Analysis 

      Darvish Rouhani, Bita (2015-12-02)
      The ever growing body of digital data is challenging conventional analytical techniques in machine learning, computer vision, and signal processing. Traditional analytical methods have been mainly developed based on the assumption that designers can work with data within the confines of their own computing environment. The growth of big data, however, ...
    • Wafer-scale films of aligned single-wall carbon nanotubes: preparation, characterization, and optoelectronic applications 

      He, Xiaowei (2015-11-20)
      Single-wall carbon nanotubes (SWCNTs) are one-dimensional materials defined by a cylindrical and hollow structure with aspect ratios of up to 10^7:1. Individual SWCNTs have been shown to possess excellent electric, optical, thermal, and mechanical properties that are promising for electronic and optoelectronic device applications. However, when they ...
    • Methods for Ripple Detection and Spike Sorting During Hippocampal Replay 

      Sethi, Ankit (2015-09-21)
      In the rat hippocampus, fast oscillations termed sharp wave ripples and an associated sequential firing of neurons, termed replay, have been identified as playing a crucial role in memory formation and learning. The term 'replay' is used since the observed spiking encodes patterns of past experiences. To determine the role of replay in learning and ...
    • Imaging and Visual Classification by Knowledge-Enhanced Compressive Imaging 

      Li, Yun (2015-09-10)
      Compressive imaging is a technology that uses multiplexed measurements and the sparsity of many natural images to efficiently capture and reconstruct images. The compressive single pixel camera is one embodiment of such an imaging system and has proven capable of imaging static images, dynamic scenes, and entire hyperspectral datacubes using fewer ...
    • Molecular Plasmonics: Graphene Plasmons in the Picoscale Limit 

      Lauchner, Adam (2015-08-20)
      Doped graphene supports surface plasmons in the mid- to far-infrared that are both electrically and spatially tunable. Graphene has been shown to enable greater spatial confinement of the plasmon and fewer losses than typical noble metals. Reduced-dimensional graphene structures, including nanoribbons, nanodisks, and other allotropes including ...
    • High-speed Track and Hold Amplifiers in CMOS for Enabling Pulse-based Direct Modulation, Secure Communication and Precision Localization 

      Aggrawal, Himanshu (2015-08-06)
      Last few decades have seen a puissant desire for fast communication links that has shaped the evolution of high-speed circuits and silicon- based technology. This desire accompanied with a large consumer market has fueled the development of ever-shrinking, faster technology nodes. These advanced nodes open doors for designers to develop new ways of ...
    • Design and Implementation of I/O Servers Using the Device File Boundary 

      Amiri Sani, Ardalan (2015-07-31)
      Due to historical reasons, today's computer systems treat I/O devices as second-class citizens, supporting them with ad hoc and poorly-developed system software. As I/O devices are getting more diverse and are taking a central role in modern systems from mobile systems to servers, such second-class system support hinders novel system services such ...
    • MU-MIMO WLANs in Diverse Bands and Environments 

      Anand, Narendra (2015-04-24)
      Multi-user MIMO (MU-MIMO) is a precoding technique that allows for an Access Point (AP) to transmit data to multiple receivers in parallel resulting in an overall capacity increase. However, achieving these gains requires significant overhead in first choosing the subset of users to serve and measuring the Channel State Information (CSI) between that ...
    • Protocol Design and Experimental Evaluation for Efficient Multi-User MIMO Wireless Networks 

      Bejarano Chavez, Oscar (2015-04-24)
      Information theoretic results on Multi-User MIMO (MU-MIMO) have demonstrated a many-fold increase in capacity compared to Single-Input Single-Output. By leveraging multiple antennas at the Access Point (AP) and beamforming techniques, MU-MIMO enables simultaneous transmissions of multiple independent streams on the downlink. Ideally, with sufficient ...
    • A Data and Platform-Aware Framework For Large-Scale Machine Learning 

      Mirhoseini, Azalia (2015-04-24)
      This thesis introduces a novel framework for execution of a broad class of iterative machine learning algorithms on massive and dense (non-sparse) datasets. Several classes of critical and fast-growing data, including image and video content, contain dense dependencies. Current pursuits are overwhelmed by the excessive computation, memory access, and ...
    • Client Beamforming for Rate Scalability of MU-MIMO Networks 

      Yu, Hang (2015-04-24)
      The multi-user MIMO (MU-MIMO) technology allows an AP with multiple antennas to simultaneously serve multiple clients to improve the network capacity. To achieve this, the AP leverages zero-forcing beamforming (ZFBF) to eliminate the intra-cell interference between served clients. However, current MU-MIMO networks suffer from two fundamental problems ...
    • Imaging Plasmons with Compressive Hyperspectral Microscopy 

      Lu, Liyang (2015-04-23)
      With the ability of revealing the interactions between objects and electromagnetic waves, hyperspectral imaging in optical microscopy is of great importance in the study of various micro/nano-scale physical and chemical phenomena. The conventional methods, however, require various scanning processes to acquire a complete set of hyperspectral data ...
    • WrAP: Hardware and Software Support for Atomic Persistence in Storage Class Memory 

      Giles, Ellis Robinson (2015-04-23)
      In-memory computing is gaining popularity as a means of sidestepping the performance bottlenecks of traditional block-based storage devices. However, the volatile nature of DRAM makes these systems vulnerable to system crashes, while the need to continuously refresh massive amounts of passive memory-resident data increases power consumption. Emerging ...