1,720,954 research outputs found
Filtered Audio Clips from Approximate FIR Filters Designed Using the SABER Algorithm
No full textThe results of using accurate and approximate finite impulse response (FIR) filters on noisy song clips are summarized here.
The names of the clips are listed along with its description.
For each song (e.g., Country), there are four versions:
a. Country_1NOISY - Noisy version of the song downloaded from the GTZAN Genre Collection (marsyas.info/downloads/datasets.html - use of audio clips permitted by collection creator and falls under fair use).
b. Country_2EXACTfilter - Filtered version using exact hardware of the FIR filter
c. Country_3APPROXifilterBudget100K - Filtered version using approximate hardware of the FIR filter with error variance 100,000.
d. Country_4APPROXifilterBudget200K - Filtered version using approximate hardware of the FIR filter with error variance 200,000.
e. Country_5APPROXifilterBudget400K - Filtered version using approximate hardware of the FIR filter with error variance 400,000.
The original songs were processed with low pass filter and 6 seconds of each data was selected for our analysis from each of the eight genres specified.
Colored noise (high frequency) was added to the 6 seconds data to generate the noisy signal. This signal was then passed through four different versions of an order-33 FIR filter to obtained the filtered versions. Each version of the filter corresponds to the exact, and approximate configurations with three different error variance budgets, and designed using the Selection of Approximate Bits for the Design of Error Tolerant Circuits (SABER) algorithm.
While the filtered signal still has some noise, it is within acceptable auditory range of human ears as compared to the noisy signal. Our paper shows how using the approximate version of the FIR filter can lead to power savings compared to the exact version, with minimal compromise on the user experience in terms of the quality of the output.We developed an algorithm, Selection of Approximate Bits for the Design of Error Tolerant Circuits (SABER), to generate an approximate circuit with the aim of maximizing the number of approximate bits in a circuit (which translates to power/area minimization) so that it uses minimal resources under a specified error budget. Our work demonstrates results on fixed-point integer arithmetic operations. The key ingredient of any methodology based on approximate design is an accurate quantification of the error injected into a computation by the approximation scheme. We use the variance of this error as the error metric to be constrained within a user-specified budget. We use an analytical expression of this error variance as a function of the total approximation in a circuit.The Doctoral Dissertation Fellowship, University of MinnesotaAwards CCF-1162267, CCF-1525925, and CCF-1525749, National Science FoundationSengupta, Deepashree; Snigdha, Farhana, S; Hu, Jiang; Sapatnekar, Sachin S. (2017). Filtered Audio Clips from Approximate FIR Filters Designed Using the SABER Algorithm. Retrieved from the University Digital Conservancy, https://doi.org/10.13020/D6BP4X
A Study on Unintentional and Intentional Sources of Variability in Nanometer Scale Digital Circuits
Full text linkUniversity of Minnesota Ph.D. dissertation. April 2017. Major: Electrical Engineering. Advisor: Sachin Sapatnekar. 1 computer file (PDF); xiii, 132 pages.As technology has scaled aggressively over the past 50 years, device reliability issues and escalated power dissipation have become growing concerns in digital very large scale integrated (VLSI) circuits. Today's integrated circuits, which implement digital systems with billions of transistors in about a square centimeter, are tremendously susceptible to inadvertent errors, and circuit modifications required to ensure error resilience incur significant power overheads that are growing alarmingly as transistor dimensions shrink. Technology scaling has thus caused a resounding effect on the performance of digital circuits due to process, voltage, temperature, and usage-related variations, and increased power dissipation, resulting in lower battery life and increased system costs. Unintentional reliability failures due to circuit aging pose serious threat for safety-critical and security applications, and must be mitigated. Intentional errors, on the other hand, can be introduced to a limited extent in circuits pertaining to error-tolerant applications, to reduce the system power without significantly affecting user experience. In this thesis, we study these two aspects of circuit reliability, i.e., the unintentional reliability failures arising out of circuit aging, and the intentional unreliability introduced in circuits implementing error-tolerant applications to reduce system power. Temporal variations are injected into circuits due to aging during the normal operation of a chip. The predominant aging effects that cause circuit delay shifts over time are bias temperature instability (BTI) and hot carrier injection (HCI), both of which cause long-term degradations in transistor performance, and result in unintentional reliability issues in circuits. These effects are exacerbated as transistor sizes reduce, causing temporal delay degradations at the circuit level, thus introducing inadvertent errors during computations. Typically, these errors are mitigated by guardbanding through circuit overdesign or by increasing the supply voltage to speed up the systems. However, both result in wasted system power, and there is a need for effective aging estimation, so that just enough adaptive techniques can be applied, for error-free operation of a circuit. On the other hand, numerous applications related to recognition, mining, and synthesis, especially those from image and audio processing domains, are error tolerant, since they pertain to the inherently limited human perception. A new design paradigm called approximate computing, leverages this error-tolerance to implement arithmetic operations through approximate circuits. In other words, circuits implementing these applications can be intentionally designed to be unreliable, to achieve significant speed-up and system power savings through simplified hardware to perform complex arithmetic operations. The desired accuracy is often a user-specified input, and a there is a need to quantify the error injected into a computation as a function of the extent of approximation to systematically obtain the tradeoff between accuracy and power savings achieved in approximate circuits to aid their design. For applications where aging-related errors are a critical problem, the first half of the thesis proposes efficient aging sensor schemes that enable system adaptation for error-free operation. On-chip ring-oscillator-based (ROSC-based) structures are chosen as the surrogate aging sensors and this thesis presents a method for inferring circuit delay shifts due to BTI and HCI aging from these sensors. The proposed method efficiently computes calibration factors that translate delay shifts in the ROSCs to those in the monitored circuits within 1% of the true values. These factors are shown to be independent of temperature and supply voltage variations in practice. Further, a refinement strategy is proposed where the sensor measurements are amalgamated with infrequent online delay measurements on the monitored circuit to partially capture its true workloads, leading to 8% lower delay guardbanding overheads compared to the conventional methods. For error-tolerant applications, the second half of the thesis proposes algorithms for error analysis, and design of approximate circuits. The proposed analysis algorithms generate the distribution of the error injected into a computation when implemented using approximate arithmetic circuits. These algorithms are based on the Fourier and the Mellin transform to efficiently compute the total error accumulated at the output of an approximate circuit abstracted as a directed acyclic graph, through its topological traversal. The resulting error distribution is obtained much faster than Monte Carlo simulations, with the error statistics being within 2% of their true values. The proposed design algorithm uses the second moment of this distribution as a guideline to construct approximate arithmetic circuits through an optimization problem which maximizes their power savings while constrained by a user-specified error budget. Fast heuristics have been proposed to solve the integer non-linear optimization problem, and over 30% improvement in power savings is achieved compared to the conventional methods.Sengupta, Deepashree. (2017). A Study on Unintentional and Intentional Sources of Variability in Nanometer Scale Digital Circuits. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/198364
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
