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Articles 7381 - 7410 of 11510

Full-Text Articles in Engineering

Spear Phishing Attack Detection, David T. Merritt Mar 2011

Spear Phishing Attack Detection, David T. Merritt

Theses and Dissertations

This thesis addresses the problem of identifying email spear phishing attacks, which are indicative of cyber espionage. Spear phishing consists of targeted emails sent to entice a victim to open a malicious file attachment or click on a malicious link that leads to a compromise of their computer. Current detection methods fail to detect emails of this kind consistently. The SPEar phishing Attack Detection system (SPEAD) is developed to analyze all incoming emails on a network for the presence of spear phishing attacks. SPEAD analyzes the following file types: Windows Portable Executable and Common Object File Format (PE/COFF), Adobe Reader, …

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Characterization Of Noise Technology Radar Signal Detectability Using A Non-Cooperative Receiver, Daniel V. Atienza Mar 2011

Characterization Of Noise Technology Radar Signal Detectability Using A Non-Cooperative Receiver, Daniel V. Atienza

Theses and Dissertations

As Noise Technology Radar (NTR) systems emerge, there is a need for non-cooperative, non-matched filter detection and exploitation. This work is based on that need and AFIT's Noise Network (NoNET) radar system. These signals are associated with Low Probability of Detection/ Intercept (LPD/LPI) signals. Quadrature Mirror Filter Banks (QMFB) has been effectively used for non-cooperatively detecting structured LPD/LPI signals and extracting various waveform characteristics. However, the QMFB process performance with unstructured NTR signals was challenging and motivated a need for a transformed QMFB. This transform was based on AFIT research by Gronholz and Mims (G-M), who used a multi-channel receiver …

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An Investigation Of Cavity Resonance And Its Relationship To Store Force And Moment Loading, Christopher J. Coley Mar 2011

An Investigation Of Cavity Resonance And Its Relationship To Store Force And Moment Loading, Christopher J. Coley

Theses and Dissertations

A store which is released from an internal bay is subjected to a highly unsteady flowfield which influences the release characteristics for the store. Pressure transducer information is often used to estimate store loading, although no direct correlation between the observed frequencies from the pressure transducers and the store loading has been developed. The relationship between the acoustic modes present in the cavity and the force and moment loading on a store released from a bay are investigated through a CFD study using the OVERFLOW 2.1 solver. The acoustic modes of the cavity are calculated from the pressure fluctuation histories …

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Perimeter Security And Intruder Detection Using Gravity Gradiometry: A Feasibility Study, Jared D. Tuinstra Mar 2011

Perimeter Security And Intruder Detection Using Gravity Gradiometry: A Feasibility Study, Jared D. Tuinstra

Theses and Dissertations

Changes in the mass distribution around some point on the Earth’s surface induce corresponding changes to the magnitude and direction of the gravity vector at that location. The nine-tensor derivative of the gravity vector, or gravity gradient, is sensitive to very small changes in the gravity vector. With some assumptions, continuous measurement of the gravity gradient using a gravity gradiometer (GGI) is used to determine the location of a mass change in the local area near the instrument. This investigation sought to determine the effectiveness, operating characteristics, and limitations of a physical perimeter security system that uses an array of …

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Software And Critical Technology Protection Against Side Channel Analysis Through Dynamic Hardware Obfuscation, John R. Bochert Mar 2011

Software And Critical Technology Protection Against Side Channel Analysis Through Dynamic Hardware Obfuscation, John R. Bochert

Theses and Dissertations

Side Channel Analysis (SCA) is a method by which an adversary can gather information about a processor by examining the activity being done on a microchip though the environment surrounding the chip. Side Channel Analysis attacks use SCA to attack a microcontroller when it is processing cryptographic code, and can allow an attacker to gain secret information, like a crypto-algorithm's key. The purpose of this thesis is to test proposed dynamic hardware methods to increase the hardware security of a microprocessor such that the software code being run on the microprocessor can be made more secure without having to change …

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Biological Investigation Of The Stimulated Flapping Motions Of The Moth, Manduca Sexta, Travis B. Tubbs Mar 2011

Biological Investigation Of The Stimulated Flapping Motions Of The Moth, Manduca Sexta, Travis B. Tubbs

Theses and Dissertations

No abstract provided.

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Image Dependent Relative Formation Navigation For Autonomous Aerial Refueling, James M. Howard Mar 2011

Image Dependent Relative Formation Navigation For Autonomous Aerial Refueling, James M. Howard

Theses and Dissertations

This research tests the feasibility, accuracy, and reliability of a predictive rendering and holistic comparison algorithm with use of an optical sensor to provide relative distance and position behind a lead or tanker aircraft. Using an accurate model of a tanker, an algorithm renders image(s) for comparison with actual collected images by a camera installed on the receiver aircraft. Based on this comparison, information used to create the rendered image(s) is used to provide the relative navigation solution required for autonomous air refueling. Given enough predicted images and processing time, this approach should reliably find an accurate solution. Building on …

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Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques, Jeremiah D. Johnson Mar 2011

Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques, Jeremiah D. Johnson

Theses and Dissertations

Navigation in indoor and urban environments by small unmanned systems is a topic of interest for the Air Force. The Advanced Navigation Technology Center at the Air Force Institute of Technology is continually looking for novel approaches to navigation in GPS deprived environments. Inertial sensors have been coupled with image aided concepts, such as feature tracking, with good results. However, feature density in areas with large, flat, smooth surfaces tends to be low. Polarimetric sensors have been used for surface reconstruction, surface characterization and outdoor navigation. This thesis combines aspects of some of these algorithms along with a realistic, micro-facet …

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Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi Mar 2011

Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi

Theses and Dissertations

Metamaterials, materials that make use of naturally occurring materials and designed structures to create materials with special properties not found in nature, are a fascinating new area of research, combining the fields of physics, microfabrication, and material science. This work will focus on the development of metamaterials operating in the visible and infrared which will be constructed and tested for basic optical properties. Possible applications for these materials will not be investigated. The this work will go into the fabrication and test of layered metal-dielectric structures, called layered metamaterials, as these structures hold potential for applications in advanced optical systems. …

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Kernelized Locality-Sensitive Hashing For Fast Image Landmark Association, Mark A. Weems Mar 2011

Kernelized Locality-Sensitive Hashing For Fast Image Landmark Association, Mark A. Weems

Theses and Dissertations

As the concept of war has evolved, navigation in urban environments where GPS may be degraded is increasingly becoming more important. Two existing solutions are vision-aided navigation and vision-based Simultaneous Localization and Mapping (SLAM). The problem, however, is that vision-based navigation techniques can require excessive amounts of memory and increased computational complexity resulting in a decrease in speed. This research focuses on techniques to improve such issues by speeding up and optimizing the data association process in vision-based SLAM. Specifically, this work studies the current methods that algorithms use to associate a current robot pose to that of one previously …

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Decision Analysis And Validation Of Value Focused Thinking Decision Models Using Multivariate Analysis Techniques, James L. Pruitt Mar 2011

Decision Analysis And Validation Of Value Focused Thinking Decision Models Using Multivariate Analysis Techniques, James L. Pruitt

Theses and Dissertations

Decision Analysis (DA) is a useful tool to assist decision makers (DM) with difficult and complex decisions using mathematical models. Value Focused Thinking (VFT) models are a useful DA tool widely employed in the Air Force. However, VFT models are rarely validated. This research will attempt to validate any given VFT model and provide insight into the discriminating attributes of the alternative set. First, a two group discriminant analysis is applied the alternative set given the prior knowledge of the selected alternatives. Next, compromise programming is used attempt to minimize the distance between the posterior probability of an alternative being …

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Alternative Active Duty Military Retirement Plan, Amy L. Schmidt Mar 2011

Alternative Active Duty Military Retirement Plan, Amy L. Schmidt

Theses and Dissertations

No abstract provided.

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Determining The Value Of Future Information, James J. Springston Mar 2011

Determining The Value Of Future Information, James J. Springston

Theses and Dissertations

Companies continuously struggle to quantify the value of their information in an attempt to gain a better understanding of the return on investment of their information technology (IT) architecture. One approach companies have taken to place a numeric value on information is to treat it as a traditional economic asset (e.g. equipment, buildings, and vehicles) that is governed by its own unique set of laws. Once an enterprise understands the behavior of information it can incorporate Skyrme's "10 value adding aspects of information" when developing IT architecture, thus maximizing the potential value of their information. Like most enterprises, the Intelligence …

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Fusion Schemes For Ensembles Of Hyperspectral Anomaly Detection Algorithms, Brooks R. Turnquist Mar 2011

Fusion Schemes For Ensembles Of Hyperspectral Anomaly Detection Algorithms, Brooks R. Turnquist

Theses and Dissertations

Hyperspectral imaging is playing an ever increasing role in our military's remote sensing operations. The exponential increase in collection operations generates more data than can be evaluated by analysts unassisted. Anomaly detectors attempt to reduce this load on analysts by identifying potential target pixels which appear anomalous when compared to what are determined to be background, or non-target, pixels. However, there is no one individual algorithm that is best suited for all situations and it can be difficult to choose the best algorithm for each individual task. Fusion techniques have been shown to reduce errors and increase generalization, eliminating the …

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Impact Of Snow Removal Operations On Thermoplastic Pavement Markings, Monica L. Monfette Mar 2011

Impact Of Snow Removal Operations On Thermoplastic Pavement Markings, Monica L. Monfette

Theses and Dissertations

This pilot study explored the effect snow removal operations have on thermoplastic pavement markings. Including snow removal as a separate independent variable is unique because much of the previous research performed on pavement marking degradation mentioned snow removal as a direct cause in a marking degrading more rapidly; however, it is mentioned as an afterthought and a suggestion to be considered in future research. This pilot study looked at 10 thermoplastic markings and all marking data were collected in the field, using a hand-held retroreflectometer. Data collected began 60 days after initial marking application and ended 12 months after initial …

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Paint Pavement Marking Performance Prediction Model That Includes The Impacts Of Snow Removal Operations, Dale M. Mull Mar 2011

Paint Pavement Marking Performance Prediction Model That Includes The Impacts Of Snow Removal Operations, Dale M. Mull

Theses and Dissertations

The results of this research effort were captured in two manuscripts drafted for publication in peer reviewed journals. The first manuscript validated a previously published model with an expanded data set, updated service life predictions for painted pavement markings using recently released pavement marking retroreflectivity minimums, and incorporated recent cost data to evaluate two alternative methods of compliance with the new retroreflectivity minimums for two-lane roads. The second manuscript developed a new performance prediction model for paint pavement markings that includes the impact of snow removal operations and then applied the model to four real-world roadways to determine if replacement …

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A Systems Architecture And Advanced Sensors Application For Real-Time Aircraft Structural Health Monitoring, Hyoungjin Shin, Edward C. Beckett Mar 2011

A Systems Architecture And Advanced Sensors Application For Real-Time Aircraft Structural Health Monitoring, Hyoungjin Shin, Edward C. Beckett

Theses and Dissertations

Aircraft are being pushed beyond their original service life, increasing the potential for structural failures. A catastrophic in flight failure of an F-15 bulkhead and severe cracking in the C-130 Wing rainbow fitting are two recent examples that have caused major problems for the Air Force. Previous Aircraft Structural Health Monitoring Systems research primarily explored using a system during the ground maintenance phase. This research will explore a Real-Time Aircraft Structural Health Monitoring System (RTASHMS) that includes a ground phase as well as an in-flight phase. The RTASHMS will continuously analyze structural hot spots, detect critical structural damage or cracks …

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Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider Mar 2011

Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider

Theses and Dissertations

An increased demand for use of Unmanned Aircraft Systems (UASs) without commensurate increases in pilot manpower has prompted proposals for simultaneous control of multiple aircraft by a single pilot or Multi-Aircraft Control (MAC). To understand the potential effects of MAC, an IMPRINT Pro, Multi-Resource Theory, pilot workload model was developed from pedigreed system architecture. Feedback from active UAS pilots was used to validate the model and establish a workload saturation threshold value of 60, above which pilots may experience performance degradation over extended periods of time. The model predicts that pilots experience low workload when operating one or two UASs …

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Performance Characterization Of A Novel Plasma Thruster To Provide A Revolutionary Operationally Responsive Space Capability With Micro- And Nano-Satellites, John-David C. De La Harpe Mar 2011

Performance Characterization Of A Novel Plasma Thruster To Provide A Revolutionary Operationally Responsive Space Capability With Micro- And Nano-Satellites, John-David C. De La Harpe

Theses and Dissertations

Few options currently exist to provide propulsion for extremely small satellites due to design constraints on power, volume, and weight. However, future operation will require a capability to conduct orbital maneuvers, momentum dumping, and precision pointing for these low cost satellites. The research presented here represents the first effort to operate and quantify the performance of a new micro plasma thruster design which provides a novel solution to these disparate competing constraints. The thruster in this study represents a deviation from traditional circular Hall thruster design practices, because it eschews a central magnetic circuit, which results in nearly parallel electric …

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Effects Of Air Drag And Lunar Third-Body Perturbations On Motion Near A Reference Kam Torus, Luke J. Hagen Mar 2011

Effects Of Air Drag And Lunar Third-Body Perturbations On Motion Near A Reference Kam Torus, Luke J. Hagen

Theses and Dissertations

The KAM Theory was developed in the 1960s but only in the last decade has it been applied to Earth orbiting satellites. Physical state variables of position and velocity are transformed into KAM Torus variables. The KAM Torus is a geometrical structure similar to that of a multi-dimensional donut. The Earth satellite's motion can be described as traversing the surface of this donut. There are two primary advantages of this transformation: (1) The new generalized coordinates which are analogous with mean anomaly, right ascension of the ascending node, and argument of perigee, increment linearly with time, and (2) Perturbations due …

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Optimized Dual Expander Aerospike Rocket, Joshua N. Hall Mar 2011

Optimized Dual Expander Aerospike Rocket, Joshua N. Hall

Theses and Dissertations

Research at the Air Force Institute of Technology (AFIT) focused on designing a cryogenic dual-expander aerospike nozzle (DEAN) upper stage rocket engine to produce 50,000 pounds-force (222.4 kilo-Newtons) vacuum thrust, 464 seconds of vacuum specific impulse and a thrust-to-weight ratio of 106.5. The use of dual expander cycles improves engine reliability, maximizes efficiency, and eliminates some catastrophic failure modes. An upper stage engine with an aerospike nozzle is shorter and lighter than an equivalent performing conventional bell nozzle upper stage engine. Previous research focused on first developing a feasible closed DEAN design model and secondly expanding the model to support …

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Fixed-Wing Aircraft Combat Survivability Analysis For Operation Enduring Freedom And Operation Iraqi Freedom, Christopher L. Jerome Mar 2011

Fixed-Wing Aircraft Combat Survivability Analysis For Operation Enduring Freedom And Operation Iraqi Freedom, Christopher L. Jerome

Theses and Dissertations

The primary tenet of the aircraft survivability discipline is threat definition. In order to deliver relevant capabilities and protection to the warfighter it is imperative; therefore, to provide timely, accurate, and actionable threat data to the survivability community. In an attempt to identify the evolution of aircraft threats in today's combat environment, an analysis of fixed-wing aircraft battle damage was conducted. This analysis reports battle damage incidents from OPERATIONS ENDURING FREEDOM (OEF) and IRAQI FREEDOM(OIF). Additionally, reported damage incidents were then validated by crosschecking aircraft maintenance records from this period to eliminate non-hostile fire data points. This revolutionary approach uncovered …

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X-Hale: The Development Of A Research Platform For The Validation Of Nonlinear Aeroelastic Codes, Alexander A. Kaszynski Mar 2011

X-Hale: The Development Of A Research Platform For The Validation Of Nonlinear Aeroelastic Codes, Alexander A. Kaszynski

Theses and Dissertations

In conjunction with the Air Force Institute of Technology (AFIT) and the Air Force Research Laboratory (AFRL), the University of Michigan has designed and is currently building a remotely piloted aircraft (RPA) experimental high altitude long endurance (X-HALE) aircraft to collect non-linear aeroelastic data to validate HALE aircraft design codes developed by academia, industry, and the federal government. While X-HALE is representative of HALE aircraft, the manufacturing and evaluation techniques are applicable to larger full size HALE aircraft such as the concepts being developed under Defense Advanced Research Projects Agency's (DARPA's) Vulture program. This paper documents the development of the …

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Heat Transfer Experiments On A Pulse Detonation Driven Combustor, Nicholas C. Longo Mar 2011

Heat Transfer Experiments On A Pulse Detonation Driven Combustor, Nicholas C. Longo

Theses and Dissertations

Heat transfer experiments were conducted using a heat exchanger behind a pulse detonation combustor and a Garrett automotive turbocharger at the Air Force Research Lab (AFRL). The equivalence ratio and purge fraction were held at 1.0 and 0.9, respectively, while the frequency of operation was varied from 10 to 12 Hz in 1 Hz movements, and the fill fraction was varied from 0.5 to 0.8 in 0.1 increments. Temperature measurements were calculated using an energy balance allowing for the calculation of heat exchanger inlet enthalpy. The heat exchanger inlet enthalpy was estimated to be the exit enthalpy of the turbocharger …

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Detonation Propagation Through Ducts In A Pulsed Detonation Engine, Jeffrey M. Nielsen Mar 2011

Detonation Propagation Through Ducts In A Pulsed Detonation Engine, Jeffrey M. Nielsen

Theses and Dissertations

Development of a continuously operating pulsed detonation engine (PDE) without a high energy ignition system or a deflagration-to- detonation transition (DDT) device will increase engine efficiency, reduce cost, improve performance, and reduce weight. This report is a study of configurations that allow a consistent and predictable transition of a detonation from one detonation tube to second tube. The intent was, via visualization of detonation propagation through a cross-over tube, to develop a cross-over passage leading to minimization of energy losses and effective and repeatable tube-to-tube initiation. Detonation tube cross-over width, cross-over geometry and fuels were varied to determine their effect …

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Experimental Measurements Of Store Separation Using Dry Ice Models In A Subsonic Flow, Michael C. Paul Mar 2011

Experimental Measurements Of Store Separation Using Dry Ice Models In A Subsonic Flow, Michael C. Paul

Theses and Dissertations

Testing free-drop store separation from a cavity in wind tunnels proves a difficult task because the models are typically destroyed during the test. Furthermore, there is potential for damage to wind tunnel components. Prior work has shown that small dry ice models released within the test section do not cause damage to the AFIT pressure-vacuum wind tunnel components or vacuum chamber. Rather, the dry ice models break apart and sublimate harmlessly into gaseous carbon dioxide. Therefore, this study was undertaken to determine whether dry ice models might prove useful in free-drop store separation testing. A generic aircraft cavity was constructed …

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Sizing Analysis For Aircraft Utilizing Hybrid-Electronic Propulsion Systems, Matthew D. Rippl Mar 2011

Sizing Analysis For Aircraft Utilizing Hybrid-Electronic Propulsion Systems, Matthew D. Rippl

Theses and Dissertations

A submerged inlet investigation, using flow control in the form of discrete blowing, examined proximity and jet directionality to improve compressor face uniformity. The flow control locations were at the head of the ramp and part way down the ramp, providing four configurations under examination. Laser Doppler velocimetry (LDV)measurements at the throat determined the effect of the flow control based on the statistical velocity measurements. Blowing at closer proximity to the throat and targeting the largest velocity deficit region provided the best results. The airspeed and inlet velocity simulated takeoff and landing conditions; velocities ranged from Mach 0.1-0.3 at the …

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Evaluation Of The Effectiveness Of A Variable Advisory Speed System On Queue Mitigation In Work Zones, Aaron B. Wilson Mar 2011

Evaluation Of The Effectiveness Of A Variable Advisory Speed System On Queue Mitigation In Work Zones, Aaron B. Wilson

Theses and Dissertations

Construction is increasing due to increased demand and degradation of existing infrastructure. This construction often results in a reduced number of traffic lanes or lane width during construction, which often creates queue at the entrance to work zones. Variable Advisory Speed Systems (VASS) provide drivers with advanced warning regarding traffic speeds downstream to help them make better decisions in advance of problems that may exist downstream. The purpose of this study was to evaluate the effectiveness of a VASS at mitigating queues in work zone entrances during peak hour conditions. It was anticipated that by implementing a VASS queues would …

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Tool Life Of Various Tool Materials When Friction Spot Welding Dp980 Steel, Christopher Shane Ridges Mar 2011

Tool Life Of Various Tool Materials When Friction Spot Welding Dp980 Steel, Christopher Shane Ridges

Theses and Dissertations

In this study, friction spot welding was used to join DP980 steel sheet. Four different ultra-hard tool materials were used with the objective of determining which tool material produced the highest number of acceptable-strength welds. Three of the tools were composed of various mixtures of polycrystalline cubic Boron Nitride (PCBN), Tungsten, and Rhenium. These materials are referred to herein as Q60, Q70, and Q80, the "Qxx" designation denoting the percentage of the volume of the tool material composed of PCBN. The fourth tool tested was composed entirely of PCBN. The Q70 tool produced approximately 1100 welds of acceptable strength before …

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Xdl-Based Hard Macro Generator, Subhrashankha Ghosh Mar 2011

Xdl-Based Hard Macro Generator, Subhrashankha Ghosh

Theses and Dissertations

In a conventional hardware design flow, the compilation process to create the physical circuit on the FPGA takes a long time. HMFlow is a design flow that reduces the compilation time by using pre-compiled modules called hard macros. HMFlow uses System Generator to create the designs, which are then converted to hard macros. The hard macro creation process takes a long time and a possible solution is a hard macro generator called XdlCoreGen, which is described in this thesis. XdlCoreGen can quickly create fully mapped and placed hard macros using XDL. XDL is a human readable design format that describes …

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