4,660 research outputs found
Scoped and typed staging by evaluation
Using a dependently typed host language, we give a well scoped-and-typed by construction presentation of a minimal two level simply typed calculus with a static and a dynamic stage. The staging function partially evaluating the parts of a term that are static is obtained by a model construction inspired by normalisation by evaluation. We then go on to demonstrate how this minimal language can be extended to provide additional metaprogramming capabilities, and to define a higher order functional language evaluating to digital circuit descriptions
Polynomial time and dependent types
We combine dependent types with linear type systems that soundly and completely capture polynomial time computation. We explore two systems for capturing polynomial time: one system that disallows construction of iterable data, and one, based on the LFPL system of Martin Hofmann, that controls construction via a payment method. Both of these are extended to full dependent types via Quantitative Type Theory, allowing for arbitrary computation in types alongside guaranteed polynomial time computation in terms. We prove the soundness of the systems using a realisability technique due to Dal Lago and Hofmann. Our long-term goal is to combine the extensional reasoning of type theory with intensional reasoning about the resources intrinsically consumed by programs. This paper is a step along this path, which we hope will lead both to practical systems for reasoning about programs’ resource usage, and to theoretical use as a form of synthetic computational complexity theory
Necessity of Rational Asset Price Bubbles in Two-Sector Growth Economies
We present plausible economic models in which an equilibrium with rational
asset price bubbles exists but equilibria with asset prices equal to
fundamental values do not. These economies feature multiple sectors with faster
economic growth than dividend growth. In our two-sector endogenous growth
model, entrepreneurs have access to a production technology subject to
idiosyncratic investment risk (tech sector) and trade a dividend-paying asset
(land). When leverage is relaxed beyond a critical value, the unique trend
stationary equilibrium exhibits a phase transition from the fundamental regime
to the bubbly regime with growth, implying the inevitability of bubbles with
loose financial conditions
LIPIcs, Volume 251, ITCS 2023, Complete Volume
LIPIcs, Volume 251, ITCS 2023, Complete Volum
A small catalogue of En-operads
In this largely expository paper, we will present a list of En -operads and
give complete, and in some cases new, proofs of the equivalences between these
operads.Comment: Apart from changing the formatting, we changed the order in Section 5
and corrected some very minor errors (typos and misprints
Development of a SQUID magnetometry system for cryogenic neutron electric dipole moment experiment
A measurement of the neutron electric dipole moment (nEDM) could hold the key to understanding why the visible universe is the way it is: why matter should predominate over antimatter. As a charge-parity violating (CPV) quantity, an nEDM could provide an insight into new mechanisms that address this baryon asymmetry. The motivation for an improved sensitivity to an nEDM is to find it to be non-zero at a level consistent with certain beyond the Standard Model theories that predict new sources of CPV, or to establish a new limit that constrains them.
CryoEDM is an experiment that sought to better the current limit of cm by an order of magnitude. It is designed to measure the nEDM via the Ramsey Method of Separated Oscillatory Fields, in which it is critical that the magnetic field remains stable throughout. A way of accurately tracking the magnetic fields, moreover at a temperature K, is crucial for CryoEDM, and for future cryogenic projects.
This thesis presents work focussing on the development of a 12-SQUID magnetometry system for CryoEDM, that enables the magnetic field to be monitored to a precision of pT. A major component of its infrastructure is the superconducting capillary shields, which screen the input lines of the SQUIDs from the pick up of spurious magnetic fields that will perturb a SQUID's measurement. These are shown to have a transverse shielding factor of , which is a few orders of magnitude greater than the calculated requirement.
Efforts to characterise the shielding of the SQUID chips themselves are also discussed. The use of Cryoperm for shields reveals a tension between improved SQUID noise and worse neutron statistics. Investigations show that without it, SQUIDs have an elevated noise when cooled in a substantial magnetic field; with it, magnetostatic simulations suggest that it is detrimental to the polarisation of neutrons in transport. The findings suggest that with proper consideration, it is possible to reach a compromise between the two behaviours.
Computational work to develop a simulation of SQUID data is detailed, which is based on the Laplace equation for the magnetic scalar potential. These data are ultimately used in the development of a linear regression technique to determine the volume-averaged magnetic field in the neutron cells. This proves highly effective in determining the fields within the pT requirement under certain conditions
Recombinant spidroins from infinite circRNA translation
Spidroins are a diverse family of peptides and the main components of spider silk. They can be used to produce sustainable, lightweight and durable materials for a large variety of medical and engineering applications. Spiders’ territorial behaviour and cannibalism precludes farming them for silk. Recombinant protein synthesis is the most promising way of producing these peptides. However, many approaches have been unsuccessful in obtaining large titres of recombinant spidroins or ones of sufficient molecular weight. The work described here is focused on expressing high molecular weight spidroins from short circular RNA molecules. Mammalian host cells were transfected with designed circular-RNA-producing plasmid vectors. A backsplicing approach was implemented to successfully circularise RNA in a variety of mammalian cell types. This approach could not express any recombinant spidroins based on a variety of qualitative protein assays. Further experiments investigated the reasons behind this.
Additionally, due to the diversity of spidroins in a large number of spider lineages, there are potentially many spidroin sequences left to be discovered. A bioinformatic pipeline was developed that accepts transcriptome datasets from RNA sequencing and uses tandem repeat detection and profile HMM annotation to identify novel sequences. This pipeline was specifically designed for the identification of repeat domains in expressed sequences. 21 transcriptomes from 17 different species, encompassing a wide selection of basal and derived spider lineages, were investigated using this pipeline. Six previously undescribed spidroin sequences were discovered. This pipeline was additionally tested in the context of the suckerin protein family. These proteins have recently been investigated for their potential properties in medicine and engineering including adhesion in wet environments. The computational pipeline was able to double the number of suckerins known to date. Further phylogenetic analysis was implemented to expand on the knowledge of suckerins. This pipeline enables the identification of transcripts that may have been overlooked by more mainstream analysis methods such as pairwise homology searches. The spidroins and suckerins discovered by this pipeline may contribute to the large repertoire of potentially useful properties characteristic of this diverse peptide family
L-Systems for Measuring Repetitiveness
In order to use them for compression, we extend L-systems (without ?-rules) with two parameters d and n, and also a coding ?, which determines unambiguously a string w = ?(?^d(s))[1:n], where ? is the morphism of the system, and s is its axiom. The length of the shortest description of an L-system generating w is known as ?, and it is arguably a relevant measure of repetitiveness that builds on the self-similarities that arise in the sequence.
In this paper, we deepen the study of the measure ? and its relation with a better-established measure called ?, which builds on substring complexity. Our results show that ? and ? are largely orthogonal, in the sense that one can be much larger than the other, depending on the case. This suggests that both mechanisms capture different kinds of regularities related to repetitiveness.
We then show that the recently introduced NU-systems, which combine the capabilities of L-systems with bidirectional macro schemes, can be asymptotically strictly smaller than both mechanisms for the same fixed string family, which makes the size ? of the smallest NU-system the unique smallest reachable repetitiveness measure to date. We conclude that in order to achieve better compression, we should combine morphism substitution with copy-paste mechanisms
gaps as derived models and correctness of mice
Assume ZF + AD + V=L(R). Let be a gap with
admissible. We analyze as a natural form of
``derived model'' of a premouse , where is found in a generic extension
of . In particular, we will have , and if ``
exists'', then and in fact have the same universe. This
analysis will be employed in further work, yet to appear, toward a resolution
of a conjecture of Rudominer and Steel on the nature of , for
-small mice . We also establish some preliminary work toward this
conjecture in the present paper.Comment: 128 page
LEAP: Efficient and Automated Test Method for NLP Software
The widespread adoption of DNNs in NLP software has highlighted the need for
robustness. Researchers proposed various automatic testing techniques for
adversarial test cases. However, existing methods suffer from two limitations:
weak error-discovering capabilities, with success rates ranging from 0% to
24.6% for BERT-based NLP software, and time inefficiency, taking 177.8s to
205.28s per test case, making them challenging for time-constrained scenarios.
To address these issues, this paper proposes LEAP, an automated test method
that uses LEvy flight-based Adaptive Particle swarm optimization integrated
with textual features to generate adversarial test cases. Specifically, we
adopt Levy flight for population initialization to increase the diversity of
generated test cases. We also design an inertial weight adaptive update
operator to improve the efficiency of LEAP's global optimization of
high-dimensional text examples and a mutation operator based on the greedy
strategy to reduce the search time. We conducted a series of experiments to
validate LEAP's ability to test NLP software and found that the average success
rate of LEAP in generating adversarial test cases is 79.1%, which is 6.1%
higher than the next best approach (PSOattack). While ensuring high success
rates, LEAP significantly reduces time overhead by up to 147.6s compared to
other heuristic-based methods. Additionally, the experimental results
demonstrate that LEAP can generate more transferable test cases and
significantly enhance the robustness of DNN-based systems.Comment: Accepted at ASE 202
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