On the Compression of Recurrent Neural Networks with an Application to LVCSR acoustic modeling for Embedded Speech Recognition

We study the problem of compressing recurrent neural networks (RNNs). In particular, we focus on the compression of RNN acoustic models, which are motivated by the goal of building compact and accurate speech recognition systems which can be run efficiently on mobile devices. In this work, we present a technique for general recurrent model compression that jointly compresses both recurrent and non-recurrent inter-layer weight matrices. We find that the proposed technique allows us to reduce the size of our Long Short-Term Memory (LSTM) acoustic model to a third of its original size with negligible loss in accuracy.Comment: Accepted in ICASSP 201

Characterizing the Arabidopsis frd3 Mutant Through an Activation Tagging Screen [abstract]

Abstract only availableFaculty Mentor: Elizabeth Rogers, Biochemistry/Nutritional SciencesIron is an essential element present in many common proteins, and is crucial in a number of metabolic pathways. This role is evident in the multiple disorders due to iron deficiency. Anemia, caused by iron deficiency, is the most common nutritional disorder affecting the world's population. As most people throughout the world depend primarily on plants for their nutritional needs, one way of reducing this problem will be to enhance the bioavailable iron content of plants. A better understanding of how plants acquire, transport and store iron is needed before this goal can be achieved. The Arabidopsis frd3 mutant constitutively activates its iron uptake mechanisms, resulting in an over accumulation of iron and other metals. This iron is however mislocalized and never enters leaf cells where it is ultimately required. Recent work has suggested that the FRD3 protein transports citrate into the root vasculature which is necessary for the correct localization of iron throughout the plant. One way to learn more about the FRD3 protein, and about iron homeostasis in plants, is through an activation tagging screen looking for suppressors of the frd3 phenotype. Briefly, the activation tagging construct has been transformed into frd3 plants using the established agrobacterium floral dip method. Suppressor mutants have been selected using a ferric chelate reductase assay. Putative mutants have been transferred to soil, and are currently growing to produce seed in order to re-analyze the next generation. After mutant confirmation, TAIL-PCR will be used to identify the activated gene. Additional mutant characterization will also be carried out at this stage. At least three classes of genes could be identified through this screen: (1) other citrate effluxers that will perform the same function as FRD3, (2) repressors of FRO2, the root ferric chelate reductase or (3) transporters that would facilitate movement of iron into leaf cells. The discovery and further characterization of these genes would greatly facilitate our understanding of iron nutrition in plants.F21C Summer Fellowshi

Dynamic Interactions of a Double-stage Photovoltaic Power Converter: Modelling and Control

Photovoltaic (PV) systems are a promising renewable source to achieve green energy targets and be part of the electricity generation. Lots of efforts have been devoted to increase the penetration level of PV systems and its share in the generated electricity. Power quality is one of the challenges that impact the penetration level of PV systems. It is important to ensure high power quality from PV systems to allow more installations to the grid. So, PV power quality issues have to be addressed properly. It was reported that the poor power quality of the PV systems might be caused by many reasons such as the large amount of PV power fluctuation, the low level of current from the PV system, and large populations of PV inverters. In addition to the aforementioned reasons, recently it was suggested that perturb and observe (P&O) controller is another source of harmonics which result in a deprived PV power quality. This newly reported problem is based on experimental observations without full understanding of the generation mechanism of these harmonics in the PV system, the relation between the P&O controller design and the generated harmonics, and the effect of these harmonics on the rest of the system. Thus, in-depth analysis of the harmonics in PV systems due to P&O controller and a solution to eliminate these harmonics are demanded. Therefore, in this research an investigation is carried out to explore P&O related harmonics in a double-stage grid-connected PV system. First, regarding the P&O related harmonics full explanation of how harmonics are generated due to the perturbing nature of the P&O controller is provided, a modelling approach is suggested to identify the frequency and the amplitude of the variations in the DC bus due to the P&O controller, the effect of different factors (e.g. weather conditions, system parameters, system operating point, and P&O architecture) on the induced harmonics are investigated. Secondly, regarding the effect of the P&O related harmonics on the rest of the system an intense simulation analysis is provided to explore the possible effect of the P&O related harmonics on increasing the interaction between the system power stages. This can help to set system design recommendations and guidelines such as sizing the dc-link capacitance and designing the system controllers. Finally, a novel mitigation solution is proposed to supress the P&O related harmonics. That can help to reduce the dynamic interaction between system power stages and improve the power quality of the PV system

Investigating Strategies to Support Reverse-Engineering of Interactive Systems

Most software applications today provide a graphical user interface (GUI), which facilitates the use of the software by offering graphical and visual elements to the users. The correctness of the user interface is fundamental to the correct implementation of the overall software. Using reverse engineering tools and methods is one of the most efficient ways to understand a system, and to assess its functionality and usability. However, traditional reverse engineering methods are not well suited to interactive elements of a system. This research examines and analyzes reverse engineering techniques of interactive systems written in the Java programming language, with the aim of creating a set of models of the entire system namely, Presentation Models (PModels) and Presentation Interaction Models (PIMs), which are very effective in describing structural and functional behavioral features of the interactive system. This study will also highlight some of the problems that exist in this domain and investigate several possibilities for improving the process

Automated Software Testing of Relational Database Schemas

Relational databases are critical for many software systems, holding the most valuable data for organisations. Data engineers build relational databases using schemas to specify the structure of the data within a database and defining integrity constraints. These constraints protect the data's consistency and coherency, leading industry experts to recommend testing them. Since manual schema testing is labour-intensive and error-prone, automated techniques enable the generation of test data. Although these generators are well-established and effective, they use default values and often produce many, long, and similar tests --- this results in decreasing fault detection and increasing regression testing time and testers inspection efforts. It raises the following questions: How effective is the optimised random generator at generating tests and its fault detection compared to prior methods? What factors make tests understandable for testers? How to reduce tests while maintaining effectiveness? How effectively do testers inspect differently reduced tests? To answer these questions, the first contribution of this thesis is to evaluate a new optimised random generator against well-established methods empirically. Secondly, identifying understandability factors of schema tests using a human study. Thirdly, evaluating a novel approach that reduces and merge tests against traditional reduction methods. Finally, studying testers' inspection efforts with differently reduced tests using a human study. The results show that the optimised random method efficiently generates effective tests compared to well-established methods. Testers reported that many NULLs and negative numbers are confusing, and they prefer simple repetition of unimportant values and readable strings. The reduction technique with merging is the most effective at minimising tests and producing efficient tests while maintaining effectiveness compared to traditional methods. The merged tests showed an increase in inspection efficiency with a slight accuracy decrease compared to only reduced tests. Therefore, these techniques and investigations can help practitioners adopt these generators in practice

Zeros of the Dedekind Zeta-Function

H. L. Montgomery proved a formula for sums over two sets of nontrivial zeros of the Riemann zeta-function. Assuming the Riemann Hypothesis, he used this formula and Fourier analysis to prove an estimate for the proportion of simple zeros of the Riemann zeta-function. We prove a generalization of his formula for the nontrivial zeros of the Dedekind zeta-function of a Galois number field, and use this formula and Fourier analysis to prove an estimate for the proportion of distinct zeros, assuming the Generalized Riemann Hypothesis

Design, synthesis, and biological evaluation of sigma receptors (σRS) ligands as potential pharmacotherapy for cancer and drug addiction

Sigma receptors are a well-defined unique class of receptors and are highly expressed in the central nervous system and also widely distributed in peripheral organs and tissues. There are two subtypes of sigma receptors: sigma-1 and sigma-2. These receptors are thought to be associated with functions and disorders such as inflammation, depression, anxiety, Alzheimer’s disease, epilepsy and drug abuse. The sigma-1 receptor has been demonstrated to be involved in acute and chronic effects of cocaine and methamphetamine toxicities. However, the role of sigma-2 receptors is less clear due to the lack of availability of detailed protein structural information and truly selective sigma-2 ligands, which hindered the pharmacological characterization of the sigma-2 subtype. In fact, the sigma-2 receptor has not yet been cloned. Several reports indicated that the activation of sigma-2 receptor also induces growth arrest and cell death in various tumor cell lines. This gives sigma-2 ligands possible application as effective agents for the treatment of cancer. In this regard, searching for selective, high affinity sigma-2 ligands led to the design and synthesis a series of isothiocyanate compounds derived from a selective sigma-2 compounds developed in our laboratory as selective irreversible sigma-2 ligands. Also, in the search for an effective drug for the treatment of cocaine abuse and addiction, and based on our previous work on CM699 that shoits ability to attenuate the cocaine self-administration. We have found that stimulant self-administration (cocaine or methamphetamine) was blocked by dual inhibition of the DAT and sigma-receptors However, CM699 had short half lives in Human and Rat liver microsomes assays (in vitro), and in rat in vivo assay. Although CM699 had a half-life of 4.4 hr in rat, a compound with utility as a treatment for stimulant abuse will need a longer half-life, achieved either by structural change or by formulation. In this regard, we have made more analogs of CM699 in order to enhance blockade of cocaine self-administration and metabolic stability. Additionally, in an effort to continue to develop highly selective sigma ligands, we have synthesized a novel series of benzofuran-based ligands, and more analogs of the highly selective sigma-1, CM304