Browsing by Subject "Digital"

Now showing 1 - 3 of 3
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    CAD algorithms dealing with process and temperature effects in digital integrated circuits.
    (2010-01) Mogal, Hushrav
    The aggressive scaling trend of the semiconductor industry to improve integrated circuit performance manifests itself as process, voltage and temperature (PVT) variations which can negatively impact design yield. The aim of this work is to deal with process (P) and temperature (T) effects and to develop software CAD analysis and optimization tools to mitigate their effects on digital integrated circuit performance. In the first part of this thesis, we aim to develop an algorithm to compute the criticality of gates in a circuit with underlying process variations. The timing criticality of a gate indicates its impact on the overall timing performance of a circuit. We propose to use graph-based techniques to linearly traverse the timing graph of a digital circuit to obtain its criticality information. Such information can be useful to a designer or optimization tool in making decisions regarding gate sizing to improve the circuit performance. Our methodology must not only improve the speed of computation but also the accuracy with which we obtain the criticality values of gates in the circuit. In the second part of this thesis, we propose to deal with temperature effects in the presence of increased scaling of devices. The sub-threshold leakage power of a digital chip, which is the wasted power in a digital circuit without doing any useful work, is exponentially dependent on the operating temperature of the chip. We propose to use techniques to exploit this dependence to reduce the sub-threshold leakage power. By rearranging the physical placement we can affect the temperature distribution of various blocks on a digital chip, thereby also affecting the total sub-threshold leakage power. We aim to develop a physical floorplanning tool to alleviate the temperature and sub-threshold leakage power by taking into account their interdependence. This work proposes to use task migration (TM) as a methodology to deal with increasing sub-threshold leakage power in future technology nodes. The main idea is to replicate certain high-power blocks in the design, and migrate tasks at regular intervals from one part of the chip to another, thereby reducing the power density and temperature of the design. We aim to develop a CAD optimization framework using floorplanning to read in a circuit description and produce a physical floorplan layout of the TM-aware design. This involves the selection of the design blocks to replicate, followed by the judicious placement of the blocks and finally the selection of an appropriate migration interval taking into account its negative impact on circuit performance. The traditional semiconductor process technology consists of a single layer of silicon on which various devices like transistors and diodes are fabricated along with several layers of metal. Besides the problems outlined above, increasing device density is forcing larger die footprints. As a result, designers are facing increased congestion of routing wires, limiting the amount of performance benefit with scaling. Three-dimensional or vertical integration technology offers a promising alternative, in which multiple layers of silicon with their associated metal layers are stacked on top of each other. Field-programmable devices are particularly suited to such a technology due to the regular layout of logic and routing elements on the die. As the final part of this thesis, we examine the benefits of vertical integration applied to field programmable logic devices.
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    Investigating the Online Presence of Immigration Organizations: Understanding the Role of Social Justice and Technical Communication
    (2021-05) Veeramoothoo, Saveena
    This dissertation investigates how immigration organizations in the US use their online presence to disseminate information. Immigration organizations are typically non-profit organizations whose mission involves helping migrants (whether with legal services, or any number of other services). This dissertation contributes to the conversations on social justice in technical and professional communication (TPC) by focusing on an often overlooked area in TPC research: migration and migrants in the US. This project contributes to the intersection of TPC and migration by investigating how immigration organizations use certain key online spaces and the information they share there. To begin, I first identified a network of national immigration organizations through hyperlinks. This network allowed me to identify two key organizations to further study, namely Lutheran Immigration and Refugee Service (LIRS) and US Citizenship and Immigration Services (USCIS). I then studied the website of each organization, focusing on their content and targeted audiences. Finally, I studied their Twitter accounts, focusing on content, targeted audiences and tweets’ metadata (including frequency of tweets, replies and retweets). Combining the results from the website analysis and Twitter analysis, I discuss the implications of the study, including voice, power and privilege, and audience engagement. Finally, I discuss the impact of the Covid-19 pandemic on the study and its implications for immigration organizations’ dissemination of information in online spaces.
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    Sensor Integration Software
    (2014-07-23) Murch, Austin