5,758 research outputs found

    Towards A Practical High-Assurance Systems Programming Language

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    Writing correct and performant low-level systems code is a notoriously demanding job, even for experienced developers. To make the matter worse, formally reasoning about their correctness properties introduces yet another level of complexity to the task. It requires considerable expertise in both systems programming and formal verification. The development can be extremely costly due to the sheer complexity of the systems and the nuances in them, if not assisted with appropriate tools that provide abstraction and automation. Cogent is designed to alleviate the burden on developers when writing and verifying systems code. It is a high-level functional language with a certifying compiler, which automatically proves the correctness of the compiled code and also provides a purely functional abstraction of the low-level program to the developer. Equational reasoning techniques can then be used to prove functional correctness properties of the program on top of this abstract semantics, which is notably less laborious than directly verifying the C code. To make Cogent a more approachable and effective tool for developing real-world systems, we further strengthen the framework by extending the core language and its ecosystem. Specifically, we enrich the language to allow users to control the memory representation of algebraic data types, while retaining the automatic proof with a data layout refinement calculus. We repurpose existing tools in a novel way and develop an intuitive foreign function interface, which provides users a seamless experience when using Cogent in conjunction with native C. We augment the Cogent ecosystem with a property-based testing framework, which helps developers better understand the impact formal verification has on their programs and enables a progressive approach to producing high-assurance systems. Finally we explore refinement type systems, which we plan to incorporate into Cogent for more expressiveness and better integration of systems programmers with the verification process

    Assembling Single RbCs Molecules with Optical Tweezers

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    Optical tweezer arrays are useful tools for manipulating single atoms and molecules. An exciting avenue for research with optical tweezers is using the interactions between polar molecules for quantum computation or quantum simulation. Molecules can be assembled in an optical tweezer array starting from pairs of atoms. The atoms must be initialised in the relative motional ground state of a common trap. This work outlines the design of a Raman sideband cooling protocol which is implemented to prepare an 87-Rubidium atom in the motional ground state of an 817 nm tweezer, and a 133-Caesium atom in the motional ground state of a 938 nm tweezer. The protocol circumvents strong heating and dephasing associated with the trap by operating at lower trap depths and cooling from outside the Lamb-Dicke regime. By analysing several sources of heating, we design and implement a merging sequence that transfers the Rb atom and the Cs atom to a common trap with minimal motional excitation. Subsequently, we perform a detailed characterisation of AC Stark shifts caused by the tweezer light, and identify several situations in which the confinement of the atom pair influences their interactions. Then, we demonstrate the preparation of a molecular bound state after an adiabatic ramp across a magnetic Feshbach resonance. Measurements of molecular loss rates provide evidence that the atoms are in fact associated during the merging sequence, before the magnetic field ramp. By preparing a weakly-bound molecule in an optical tweezer, we carry out important steps towards assembling an array of ultracold RbCs molecules in their rovibrational ground states

    Systemic Circular Economy Solutions for Fiber Reinforced Composites

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    This open access book provides an overview of the work undertaken within the FiberEUse project, which developed solutions enhancing the profitability of composite recycling and reuse in value-added products, with a cross-sectorial approach. Glass and carbon fiber reinforced polymers, or composites, are increasingly used as structural materials in many manufacturing sectors like transport, constructions and energy due to their better lightweight and corrosion resistance compared to metals. However, composite recycling is still a challenge since no significant added value in the recycling and reprocessing of composites is demonstrated. FiberEUse developed innovative solutions and business models towards sustainable Circular Economy solutions for post-use composite-made products. Three strategies are presented, namely mechanical recycling of short fibers, thermal recycling of long fibers and modular car parts design for sustainable disassembly and remanufacturing. The validation of the FiberEUse approach within eight industrial demonstrators shows the potentials towards new Circular Economy value-chains for composite materials

    The Active CryoCubeSat Technology: Active Thermal Control for Small Satellites

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    Modern CubeSats and Small Satellites have advanced in capability to tackle science and technology missions that would usually be reserved for more traditional, large satellites. However, this rapid growth in capability is only possible through the fast-to-production, low-cost, and advanced technology approach used by modern small satellite engineers. Advanced technologies in power generation, energy storage, and high-power density electronics have naturally led to a thermal bottleneck, where CubeSats and Small Satellites can generate more power than they can easily reject. The Active CryoCubeSat (ACCS) is an advanced active thermal control technology (ATC) for Small Satellites and CubeSats, which hopes to help solve this thermal problem. The ACCS technology is based on a two-stage design. An integrated miniature cryocooler forms the first stage, and a single-phase mechanically pumped fluid loop heat exchanger the second. The ACCS leverages advanced 3D manufacturing techniques to integrate the ATC directly into the satellite structure, which helps to improve the performance while simultaneously miniaturizing and simplifying the system. The ACCS system can easily be scaled to mission requirements and can control zonal temperature, bulk thermal rejection, and dynamic heat transfer within a satellite structure. The integrated cryocooler supports cryogenic science payloads such as advanced LWIR electro-optical detectors. The ACCS hopes to enable future advanced CubeSat and Small Satellite missions in earth science, heliophysics, and deep space operations. This dissertation will detail the design, development, and testing of the ACCS system technology

    2023-2024 Undergraduate Catalog

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    2023-2024 undergraduate catalog for Morehead State University

    2023-2024 Boise State University Undergraduate Catalog

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    This catalog is primarily for and directed at students. However, it serves many audiences, such as high school counselors, academic advisors, and the public. In this catalog you will find an overview of Boise State University and information on admission, registration, grades, tuition and fees, financial aid, housing, student services, and other important policies and procedures. However, most of this catalog is devoted to describing the various programs and courses offered at Boise State

    Running Shoe Pedometer

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    Running shoe pedometer aims to solve the issue of worn out running shoes. It can be difficult to know just how many miles you have run in your shoes and when a new pair is needed. Running in old shoes and worn out shoes is heavily linked to injury. My proposed project is a device that is powered by the compressive forces on the shoes soles that counts the number of steps the wearer takes using a microcontroller. Then, when the shoe reaches milestone that indicate it has been used 75% 90% and 100% of its expected life, it will output the information to the user. In order to output the wear life of the shoes to the user, a series of color changing chemical reactions will be used. These reactions will most likely be acid/base with some type of indicator or an electrochromic material. These color changes will allow the user to see that their shoes are worn out. The device should be extremely low cost so that it can be built into a running shoe and disposed of when the shoe is worn out

    Extension of the L1Calo PreProcessor System for the ATLAS Phase-I Calorimeter Trigger Upgrade

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    For the Run-3 data-taking period at the Large Hadron Collider (LHC), the hardware- based Level-1 Calorimeter Trigger (L1Calo) of the ATLAS experiment was upgraded. Through new and sophisticated algorithms, the upgrade will increase the trigger performance in a challenging, high-pileup environment while maintaining low selection thresholds. The Tile Rear Extension (TREX) modules are the latest addition to the L1Calo PreProcessor system. Hosting state-of-the-art FPGAs and high-speed optical transceivers, the TREX modules provide digitised hadronic transverse energies from the ATLAS Tile Calorimeter to the new feature extractor (FEX) processors every 25 ns. In addition, the modules are designed to maintain compatibility with the original trigger processors. The system of 32 TREX modules has been developed, produced and successfully installed in ATLAS. The thesis describes the functional implementation of the modules and the detailed integration and commissioning into the ATLAS detector

    Multimaterial 3D/4D Printing by Integrating Digital Light Processing and Direct Ink Writing

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    Driven by the growing demand of applications in robotics, electronics, biomedical devices and wearable devices, multi-material 3D printing has now become a trend to offer solutions with a wide choice of materials with various mechanical, chemical, thermal-mechanical, or electrical properties. However, it remains a challenge to find an approach, with a wide choice of materials, to realize high-resolution multi-material 3D printing efficiently. In this study, an innovative hybrid multi-material 3D printing system is developed, which integrates digital light processing (DLP), and direct ink writing (DIW). Here, DLP can efficiently provide a high-resolution matrix, with complex geometry and multicolor appearance, while DIW can add functionality to the component due to the wide choice of functional materials, such as shape memory photopolymers, conductive inks, and liquid crystal elastomers (LCE). With this hybrid 3D printing system, multicolor functional devices, circuit-embedding architectures, soft sensors, hybrid active lattices, active tensegrities, functionally graded actuators, and pure LCE lattices were successfully fabricated, showing a great prospect in the area of electronics, smart wearable devices, soft robots and actuators.Ph.D

    CMOS + stochastic nanomagnets: heterogeneous computers for probabilistic inference and learning

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    Extending Moore's law by augmenting complementary-metal-oxide semiconductor (CMOS) transistors with emerging nanotechnologies (X) has become increasingly important. Accelerating Monte Carlo algorithms that rely on random sampling with such CMOS+X technologies could have significant impact on a large number of fields from probabilistic machine learning, optimization to quantum simulation. In this paper, we show the combination of stochastic magnetic tunnel junction (sMTJ)-based probabilistic bits (p-bits) with versatile Field Programmable Gate Arrays (FPGA) to design a CMOS + X (X = sMTJ) prototype. Our approach enables high-quality true randomness that is essential for Monte Carlo based probabilistic sampling and learning. Our heterogeneous computer successfully performs probabilistic inference and asynchronous Boltzmann learning, despite device-to-device variations in sMTJs. A comprehensive comparison using a CMOS predictive process design kit (PDK) reveals that compact sMTJ-based p-bits replace 10,000 transistors while dissipating two orders of magnitude of less energy (2 fJ per random bit), compared to digital CMOS p-bits. Scaled and integrated versions of our CMOS + stochastic nanomagnet approach can significantly advance probabilistic computing and its applications in various domains by providing massively parallel and truly random numbers with extremely high throughput and energy-efficiency
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