Integrating microfluidics and biosensing on a single flexible acoustic device using hybrid modes

Integration of microfluidics and biosensing functionalities on a single device holds promise in continuous health monitoring and disease diagnosis for point-of-care applications. However, the required functions of fluid handling and biomolecular sensing usually arise from different actuation mechanisms. In this work, we demonstrate that a single acoustofluidic device, based on a flexible thin film platform, is able to generate hybrid waves modes, which can be used for fluidic actuation (Lamb waves) and biosensing (thickness shear waves). On this integrated platform, we show multiple and sequential functions of mixing, transport and disposal of liquid volumes using Lamb waves, whilst the thickness bulk shear waves allow us to sense the chemotherapeutic Imatinib, using an aptamer-based strategy, as would be required for therapy monitoring. Upon binding, the conformation of the aptamer results in a change in coupled mass, which has been detected. This platform architecture has the potential to generate a wide range of simple sample-to-answer biosensing acoustofluidic devices

On Sequential Functions and Fine-Grained Cryptography

A sequential function is, informally speaking, a function $f$ for which a massively parallel adversary cannot compute substantially faster than an honest user with limited parallel computation power. Sequential functions form the backbone of many primitives that are extensively used in blockchains such as verifiable delay functions (VDFs) and time-lock puzzles. Despite this widespread practical use, there has been little work studying the complexity or theory of sequential functions. Our main result is a black-box oracle separation between sequential functions and one-way functions: in particular, we show the existence of an oracle $\mathcal{O}$ that implies a sequential function but not a one-way function. This seems surprising since sequential functions are typically constructed from very strong assumptions that imply one-way functions and also since time-lock puzzles are known to imply one-way functions (Bitansky et al., ITCS \u2716). We continue our exploration of the theory of sequential functions. We show that, informally speaking, the decisional, worst-case variant of a certain class of sequential function called a continuous iterative sequential function (CISF) is PSPACE-complete. A CISF is, in a nutshell, a sequential function $f$ that can be written in the form $f \left(k, x \right) = g^{k} \left(x \right)$ for some function $g$ where $k$ is an input determining the number of rounds the function is evaluated. We then show that more general forms of sequential functions are not contained in PSPACE relative to a random oracle. Given these results, we then ask if it is possible to build any interesting cryptographic primitives from sequential functions that are not one-way. It turns out that even if we assume just the existence of a CISF that is not one-way, we can build certain fine-grained cryptographic primitives where security is defined similarly to traditional primitives with the exception that it is only guaranteed for some (generally polynomial) amount of time. In particular, we show how to build fine-grained symmetric key encryption and fine-grained MACs from a CISF. We also show how to build fine-grained public-key encryption from a VDF with a few extra natural properties and indistinguishability obfucsation (iO) for null circuits. We do not assume one-way functions. Finally, we define a primitive that we call a commutative sequential function - essentially a sequential function that can be computed in sequence to get the same output in two different ways - and show that it implies fine-grained key exchange

Degree of Sequentiality of Weighted Automata

Weighted automata (WA) are an important formalism to describe quantitative properties. Obtaining equivalent deterministic machines is a longstanding research problem. In this paper we consider WA with a set semantics, meaning that the semantics is given by the set of weights of accepting runs. We focus on multi-sequential WA that are defined as finite unions of sequential WA. The problem we address is to minimize the size of this union. We call this minimum the degree of sequentiality of (the relation realized by) the WA. For a given positive integer k, we provide multiple characterizations of relations realized by a union of k sequential WA over an infinitary finitely generated group: a Lipschitz-like machine independent property, a pattern on the automaton (a new twinning property) and a subclass of cost register automata. When possible, we effectively translate a WA into an equivalent union of k sequential WA. We also provide a decision procedure for our twinning property for commutative computable groups thus allowing to compute the degree of sequentiality. Last, we show that these results also hold for word transducers and that the associated decision problem is PSPACE -complete

The pragmatic properties and sequential functions of the Japanese sentence-final particles ne, yo and yone

Sentence-final particles in Japanese have proved notoriously difficult to explain and are especially challenging for second language users. This thesis examines the role of the Japanese sentence-final particles, ne, yo and yone, in talk-in-interaction with the aim of providing a comprehensive understanding that accounts for their pragmatic properties and sequential functions and that provides a sound basis for second language pedagogy. Taking as a starting point the failure of existing studies to provide a clear account as to why the particles occur only in interaction, this thesis argues that the pragmatic properties of ne, yo and yone have an important sequential function - that of indicating how the next turn is to relate to the existing turn. Thus the sentence-final particles have a grounding function and provide speakers of Japanese with a means of realizing the figure/ground properties of tums in talk-in-interaction. The function of each particle proposed in this study is shown below: Ne occurs when the speaker proposes that the figure emerging in the talk should be treated as a ground for the next proposition without further ado, typically in the expectation that the figure is either already known to the addressee or readily acceptable (pragmatic property) and thus directs the addressee's acceptance (sequential function).Yo occurs when the speaker intends the figure emerging in the talk to be grounded, typically in the expectation that the figure is either new to the addressee or even controversial (pragmatic property) and thus directs an appropriate response by the addressee (sequential function). We call a response triggered by the force of yo an assumptive response since, as well as being sequentially appropriate, such a response also provides an inferentially related proposition as the next contribution. This next contribution may also be provided by the original speaker. In yone constructions, yo falls within the scope of ne so that the speaker proposes that the figure emerging in the talk satisfies the criterion for having yo attached to it (pragmatic property) and thus directs the addressee's acceptance of this property (sequential function). In the appropriate context, as well as responding obligatorily to the force of we, a good conversationalist may also respond to the force of yo. The study also considers cases where no particle occurs, and proposes the function of the non-use of any particle (i.e. zero) as follows: Zero occurs when the speaker gives no intention as to how the figure emerging in the talk is grounded (pragmatic property) and thus directs the addressee to regard zero marked contributions as potentially topic closing (sequential fiinction).Although the motivation of the present research is pedagogical, the investigator expects this thesis to make a contribution to the rationalistic/empirical debate in pragmatics (Kopytko 1995, 2001 and 2004). The present research clearly illustrates the importance of understanding instances of talk in their sequential context rather than focusing on individual utterances. The study sets out rationalistically in the sense that decontextualized examples are used to set up a Particle Function Hypothesis, and then moves to an empirical stage where naturally occurring talk data are used to test the validity of the hypothesis. The approach followed in this investigation could thus be viewed as an attempt to bring together rationalistic and empirical pragmatic methods