Department Publications

This paper presents an implementation technique for the 40Gbps Ethernet Physical Coding Sublayer (PCS). The functionality of the 40Gbps Ethernet PCS is specified in the IEEE 802.3ba standard's clause 82. The paper also presents a scheme of verification of this implementation using an FPGA setup.

The spectrum of an object moving in 5-D light field videos (also known as plenoptic videos) with constant velocity and at non-constant depth is analyzed. Based on this analysis, a novel 5-D IIR adaptive depth-velocity filter is proposed for enhancing such objects. The time-variant coefficients of the proposed 5-D IIR adaptive depth-velocity filter are derived in closed form. Numerical simulation results confirm the effectiveness of the proposed filter compared to 3-D IIR adaptive velocity filters and 4-D IIR adaptive depth filters.

Five-dimensional (5-D) light field video (LFV) (also known as plenoptic video) is a more powerful form of representing information of dynamic scenes compared to conventional three-dimensional (3-D) video. In this dissertation, the spectra of moving objects in LFVs are analyzed, and it is shown that such moving objects can be enhanced based on their depth and velocity by employing 5-D digital filters, what is defined as depth-velocity filters. In particular, the spectral region of support (ROS) of a Lambertian object moving with constant velocity and at constant depth is shown to be a skewed 3-D hyperfan in the 5-D frequency domain. Furthermore, it is shown that the spectral ROS of a Lambertian object moving at non-constant depth can be approximated as a sequence of ROSs, each of which is a skewed 3-D hyperfan, in the 5-D continuous frequency domain. Based on the spectral analysis, a novel 5-D finite-extent impulse response (FIR) depth-velocity filter and a novel ultra-low complexity 5-D infinite-extent impulse response (IIR) depth-velocity filter are proposed for enhancing objects moving with constant velocity and at constant depth in LFVs. Furthermore, a novel ultra-low complexity 5-D IIR adaptive depth-velocity filter is proposed for enhancing objects moving at non-constant depth in LFVs. Also, an ultra-low complexity 3-D linear-phase IIR velocity filter that can be incorporated to design 5-D IIR depth-velocity filters is proposed. To the best of the author’s knowledge, the proposed 5-D FIR and IIR depth-velocity filters and the proposed 5-D IIR adaptive depth-velocity filter are the first such 5-D filters applied for enhancing moving objects in …

The outage probability of a two-hop coordinated decode-and-forward relay network is investigated. The case of two interfering cells is considered. This is analogous to the case when network coordination is performed with the dominant cochannel interfering cell. Different levels of network coordination are studied and their performances are compared. Exact expressions are derived for of the system for each coordination method. The impact of user location randomness on the outage probability is investigated.

We present a sensor platform to be mounted on the white cane used by the visually impaired. This can estimate the direction of user movement and enable the user to detect obstacles lying on the path in advance. The sensor platform contains an ultrasonic sensor and an IMU (Inertia Measurement Unit). We develop a model to estimate distances to obstacles in the path and their width based on sensor measurements. The model is demonstrated to have an overall accuracy of 84%, with accuracy as high as 90% for obstacles within 50cm in front of the user. Knowledge of obstacle locations and their size in advance, would enable us to guide visually impaired persons to deviate from their path and return to it after the obstacle has been passed.

Large debris created after natural disasters restrict access to inner parts of affected regions and slows down disaster relief operations. Power shovels are often used to clear wreckage but the process can take a lot of time. Moreover, it is dangerous to involve human workers in such conditions due to loose debris collapsing and causing severe damage. To speedup access to inner areas, instead of removing obstacles, they can be surmounted with the assistance of a carefully maneuvered power shovel arm. In this paper, an autonomous obstacle surmounting technique for an unmanned power shovel is proposed. Out of different sequences, the one that optimizes the total energy consumption is selected as the best candidate for surmounting a given obstacle by dynamic simulations. The experiments conducted using a miniaturized power shovel show the effectiveness of the proposed method.

The massive volume of video and image data, compels them to be stored in a distributed file system. To process the data stored in the distributed file system, Google proposed a programming model named MapReduce. Existing methods of processing images held in such a distributed file system, requires whole image or a substantial portion of the image to be streamed every time a filter is applied. In this work an image filtering technique using MapReduce programming model is proposed, which only requires the image to be streamed only once. The proposed technique extends for a cascade of image filters with the constrain of a fixed kernel size. To verify the proposed technique for a single filter a median filter is applied on an image with salt and pepper noise. In addition a corner detection algorithm is implemented with the use of a filter cascade. Comparison of the results of noise filtering and corner detection …

Two novel computationally efficient implementations for 3-D FIR cone filters are proposed in this paper. In the proposed implementations, the well-known 1-D quadrature mirror cosine modulated and 1-D directly designed temporal filter banks are cascaded with 2-D FIR circularly symmetric lowpass spatial filters to approximate the cone-shaped passband. Furthermore, the 3-D FIR frustum filters are derived from the proposed 3-D FIR cone filter implementations. The proposed implementations provide additional 2 dB signal-to-interference-and-noise ratio improvement compared to previously reported 3-D FIR cone and frustum filter implementations with reduced or equivalent computational complexity.

Large debris created after natural disasters restrict access to inner parts of affected regions, and slows down disaster relief operations. Power shovels are often used to clear wreckage but the process can take a lot of time. Moreover, it is dangerous to involve human workers operating heavy machinery in such unstable conditions. To speedup access to inner areas, obstacles can be surmounted with the assistance of carefully maneuvered power shovel arm, instead of removing them. In this work, an autonomous obstacle surmounting technique for an unmanned power shovel is proposed. Out of different sequences, the one that optimizes the total energy consumption is chosen as the best candidate for surmounting a given step-like obstacle. Dynamic simulation results show the effectiveness of the proposed method.

The outage probability of a two-hop coordinated decode-and-forward relay network is investigated. Relay coordination is performed only with the dominant interferer. Different levels of network coordination are studied and their performances are compared. Exact expressions are derived for the outage probability of a particular mobile user for each coordination scheme. Asymptotic outage probability is derived to identify the diversity and coding gains for each coordination scheme.

When establishing object correspondence across non-overlapping cameras, the existing methods combine separate likelihoods of appearance and kinematic features in a Bayesian framework, constructing a joint likelihood to compute the probability of re-detection. A drawback of these methods is not having a proper approach to reduce the search space when localizing an object in a subsequent camera once the kinematic and appearance features are extracted in the current camera. In this work we introduce a novel methodology to condition the location of an object on its appearance and time, without assuming independence between appearance and kinematic features, in contrast to existing work. We characterize the linear movement of objects in the unobserved region with an additive Gaussian noise model. Assuming that the cameras are affine, we transform the noise model onto the image plane of …

The inverse transform function of the HEVC Decoder has grown greatly in complexity with the addition of larger transform sizes and recent works have focused on efficient architectures that can achieve the required throughput. In this work we make the observation that a majority of the coefficients in a typical transform operation is zero, and therefore has no impact on the final outcome. We propose an architecture that can efficiently operate on such sparse matrices and introduce a scheduling strategy which completes a 2D IDCT with bare minimum iterations, with the added advantage of being able to integrate seamlessly with the entropy decoder without a coefficient reordering buffer. Experiments show that although the performance of this approach is scalable with the bit rate, a 120 MHz operating frequency is sufficient to handle QHD @ 48 Mbps, which is less than one third of the frequency requirement of prior work.

An ergodic rate analysis is presented for relay coordination schemes of two-hop decode-and forward relay networks. A simplified two-cell network model is used in the analysis. This model is related to a practically significant case, where the relay coordination is implemented with the cell which causes the most dominant cochannel interference level. Closed-form expressions are derived for the ergodic rate of the system. Simplified approximations are derived to approximate the ergodic rate behaviour in the asymptotically high signal-to-noise ratio regime.

The demand for high data rate wireless services has grown tremendously. The demand is expected to grow further at an increased pace. The scarcity of the usable radio frequency spectrum is a major bottleneck to cater to the growing demand for high data rate wireless services. Current cellular wireless networks rely on deploying small cells as a possible solution to cater to the growing demand. However, this practice has resulted in severe co-channel interference (CCI) levels in cellular networks. The first phase of this thesis investigates the impact of CCI on relay networks and distributed antenna systems, which are included in recent wireless standards such as long-term evolution advanced (LTE-A). The analytical results derived for system performance metrics, such as the outage probability and the ergodic rate, are used to obtain valuable insights for system design. The second stage of this thesis research …

Pitch and airspeed responses of a medium scale UAV were identified using the prediction error method. Data collection was conducted with an active closed loop autopilot control system. A naive SISO open loop transfer function was estimated using the parametric direct approach. Since its predictability was not significant, better estimators were developed using MISO parametric direct, and SISO parametric indirect method. The model validations were done to quantify their predictability.

Power shovels are used to clear wreckage after natural disasters but the process can consume a lot of time. Furthermore, operating such heavy machines in those circumstances is very dangerous for the involved human workers. To speed up access to inner parts of disaster stricken areas, obstacles can be surmounted with the assistance of carefully maneuvered arm, instead of removing them. In this paper, an autonomous obstacle surmounting technique for an unmanned power shovel is proposed. Out of different sequences, the one that optimizes the total energy consumption is chosen as the best candidate for surmounting a given step-like obstacle. Simulation and experiment results show the effectiveness of the proposed method.

A theoretical framework is presented for the evaluation of sum ergodic rate of a full-duplex underlay device-to-device network, when it shares the uplink resources of a conventional cellular user. The sum-rate of the full-duplex network is compared with a half-duplex network with equivalent radio frequency hardware complexity. Closed-form approximations are derived for the sum ergodic rate of the systems. Furthermore, the sum-rate performances are investigated for the case when a transmit power constraint is imposed on the underlay network to minimize the interference on the cellular network. The analytical results presented can be used as a tool to identify when full-duplex transmissions are viable in underlay device-to-device networks.

A new trajectory planning method for generating bounded and continuous jerk trajectories in joint space has been developed and tested. In manipulator trajectory planning, reduced jerk trajectories are desired for path tracking and vibration suppression. The proposed interpolation algorithm in this research generates a spline, composed with 5th-order, 3rdorder and 5th-order polynomial segments (5-3-5 spline) which can be used for point-to-point trajectories and trajectories with via points. The generated trajectories are continuously differentiable in position, velocity, acceleration, and has a start and end zero bounded continuous jerk profile. The algorithm allows the user to independently define the position, velocity, acceleration and jerk values at both start and end points, via point positions and velocities. These user definable parameters in the proposed 5-3-5 spline algorithm gives the flexibility for generating …

Automatic stroke recognition of badminton video footages plays an important role in the process of analyzing players and building up statistics. Yet recognizing activities from broadcast videos is a challenging task due to person dependant body postures and blurring of the fast moving body parts. We propose a robust and an accurate approach for badminton stroke recognition using dense trajectories and trajectory aligned HOG features which are calculated inside local bounding boxes around players. A four-class SVM classifier is then used to classify badminton strokes to be either smash, forehand, backhand or other. This approach is robust to noisy backgrounds and provides accurate results for low resolution broadcast videos. Our experiments also reveal that this approach needs relatively fewer training samples for accurate recognition of strokes compared to existing approaches.

This paper studies downlink coverage maximization for cellular networks in which base station (BS) locations are modeled using a spatial Poisson point process, considering three different coverage models, and under constraints on transmit power, BS density and transmit power density. Firstly, the coverage optimization problem is solved analytically for the first coverage model that focuses on noise-limited communication by ignoring interference and random fading effects. This model provides useful insights into the significance of bounded path loss models to obtain meaningful solutions for this problem. The other two coverage models are based on the users' received signal-to-interference-plus-noise-ratio (\sinr) from their associated BSs. For these models, it is shown that the coverage optimization problem can be reduced to a constrained single dimensional optimization problem without any loss of optimality …

Brain-computer interfaces (BCIs) require real-time feature extraction for translating input EEG signals recorded from a subject into an output command or decision. Owing to the inherent difficulties in EEG signal processing and neural decoding, many of the feature extraction algorithms are complex and computationally demanding. Presently, software does exist to perform real-time feature extraction and classification of EEG signals. However, the requirement of a personal computer is a major obstacle in bringing these technologies to the home and mobile user affording ease of use. We present the FPGA design and novel architecture of a generalized platform that provides a set of predefined features and preprocessing steps that can be configured by a user for BCI applications. The preprocessing steps include power line noise cancellation and baseline removal while the feature set includes a combination of linear …

The DV-Hop algorithm is an attractive option for the localization of nodes in a wireless sensor network due to its simplicity. However it suffers from poor accuracy. This paper presents a novel algorithm to enhance the accuracy of this algorithm. The idea is to use the DV-Hop algorithm to estimate positions of the anchors which are already known. The estimation errors so obtained are then minimized through an optimization algorithm which finds the optimum correction to the hop size. The locations of the unknown nodes are then estimated with the modified hop size using least squares estimation. We examine the performance of the algorithm for varying node numbers, anchor ratios and radio range. The results show that the proposed algorithm has better performances in localization precision and stability than the original DV-Hop algorithm.

This paper studies the outage capacity of a network consisting of a multitude of heterogeneous mobile users and operating according to the classical opportunistic beamforming framework. The base station is located at the center of the cell, which is modeled as a disk of finite radius. The random user locations are modeled using a homogeneous spatial Poisson point process. The received signals are impaired by both fading and location dependent path loss. For this system, we first derive an expression for the beam outage probability. This expression holds for all path loss models that satisfy some mild conditions. Then, we focus on two specific path loss models ( i.e. , an unbounded model and a more realistic bounded one) to illustrate the applications of our results. In the large system limit, where the cell radius tends to infinity, the beam outage capacity and its scaling behavior are derived for the selected specific …

A low-complexity 3D FIR filter is proposed for selectively enhancing severely corrupted linear trajectory spatio-temporal signals. The proposed 3D FIR filter is separable and consists of a 3D spatio-temporal wide-angle FIR cone filter between two 2D spatial variable-shift filters. Low complexity of the 3D spatio-temporal wide-angle FIR cone filter is achieved by exploiting the spatial-symmetry of the passband and by employing maximal decimation in the temporal dimension. Compared to existing techniques, the proposed 3D FIR filter provides significant reduction of the computational complexity for similar SINR improvement.

A multibeam filter bank (MBFB) is proposed for recovering the broadband far-field signals received from multiple directions while rejecting interfering signals and noise. The MBFB consists of two sections. The first section employs variable fractional delays and independently steers the directions of the multiple beams. It achieves low complexity by using the Farrow structure. The second section achieves low complexity by maximal decimation methods and by exploiting the spatial symmetry of a 3-D double-frustum-shaped passband. Superior performance and lower complexity compared with previous methods are numerically confirmed for a typical narrow-angle broadband multibeam beamformer of the type that could be used in radio astronomy.