220 research outputs found

    The Fed and Stock Market: A Proxy and Instrumental Variable Identification

    Get PDF
    Stock market fluctuations are likely to be an important determinant of monetary policy decisions because of their potential impact on macroeconomy. At the same time, innovations in fed fund rates affect stock prices as they change the expected future real interest rates. In this paper we apply a new identification procedure, based on proxy and IV variables, to estimate the contemporaneous relations between stock market and monetary policy without imposing any exclusion restrictions on the parameters of interest. Our empirical results indicate: first, that monetary policy responds in a positive fashion to contemporaneous changes in the stock market, but this relationship is not significant; second, that stock returns respond negatively to a positive monetary policy shock and that this response is significant at 1% level. This estimation analysis, while indicating that stock market participants react strongly and significantly to monetary policy innovations, seems to confirm the fact that in the past the Fed has not directly targeted asset prices in the conduct of monetary policy.monetary policy, financial markets, structural VAR, identification

    Proof-Relevant Resolution for Elaboration of Programming Languages

    Get PDF
    Proof-relevant resolution is a new variant of resolution in Horn-clause logic and its extensions. We propose proof-relevant resolution as a systematic approach to elaboration in programming languages that is close to formal specification and hence allows for analysis of semantics of the language. We demonstrate the approach on two case studies; we describe a novel, proof-relevant approach to type inference and term synthesis in dependently types languages and we show how proof-relevant resolution allows for analysis of inductive and coinductive soundness of type class resolution. We conclude by a discussion of overall contributions of our current work

    Surface plasmon pesonance immunosensor for the detection of campylobacter jejuni

    Get PDF
    Campylobacteriosis is an internationally important foodborne disease caused by Campylobacter jejuni. The bacterium is prevalent in chicken meat and it is estimated that as much as 90% of chicken meat on the market may be contaminated with the bacterium. The current gold standard for the detection of C. jejuni is the culturing method, which takes at least 48 h to confirm the presence of the bacterium. Hence, the aim of this work was to investigate the development of a Surface Plasmon Resonance (SPR) sensor platform for C. jejuni detection. Bacterial strains were cultivated in-house and used in the development of the sensor. SPR sensor chips were first functionalized with polyclonal antibodies raised against C. jejuni using covalent attachment. The gold chips were then applied for the direct detection of C. jejuni. The assay conditions were then optimized and the sensor used for C. jejuni detection, achieving a detection limit of 8 × 106 CFU·mL−1. The sensitivity of the assay was further enhanced to 4 × 104 CFU·mL−1 through the deployment of a sandwich assay format using the same polyclonal antibody. The LOD obtained in the sandwich assay was higher than that achieved using commercial enzyme-linked immunosorbent assay (ELISA) (106–107 CFU·mL−1). This indicate that the SPR-based sandwich sensor method has an excellent potential to replace ELISA tests for C. jejuni detection. Specificity studies performed with Gram-positive and Gram-negative bacteria, demonstrated the high specific of the sensor for C. jejuni

    Measurement of internal combustion engine performance on a chassis dynamometer

    Get PDF
    Od počátku automobilového průmyslu již uplynula spousta let a na vlastnosti vozidel i všech jeho součástí, především motoru, je kladen stále větší a větší důraz jak z hlediska bezpečnosti, tak z hlediska výkonu a ekologie. Výkon spalovacího motoru spolu s řadou dalších vlastností vozidel je měřen na válcových dynamometrech. Cílem práce je tedy popis a rozbor vyráběných dynamometrů, zkoušek, které na nich jsou prováděny, a také samotné měření výkonu spalovacího motoru na válcovém dynamometru. V závěru už je pouze uvedeno zhodnocení dopadu zkoušek na automobilový průmysl.Since the beginning of the automotive industry, a lot of years have passed and the characteristics of vehicles and all its components, especially the engine, are being given greater and greater emphasis both in terms of safety, performance and ecology. The performance of the internal combustion engine, along with a number of other vehicle features, is measured on chassis dynamometers. The aim of the thesis is to describe and analyse the dynamometers produced, the tests performed on them and also to measure the performance of the internal combustion engine on the chassis dynamometer. In conclusion, the assessment of the impact of tests on the automotive industry is just mentioned.

    Heidenhain tools for programming of CNC machines

    Get PDF
    Moderní obráběcí stroje jsou vybaveny řídicími systémy, které jsou pomyslným mozkem celého stroje. Tyto řídicí systémy jsou vyvíjeny, dále spravovány a neustále inovovány mnoha firmami a je tedy jasné, že je i na poli řídicích systémů jakýsi konkurenční boj. Cílem této práce je převážně popsat možnosti jednoho z velikánů mezi vývojáři řídicích systémů, a to od společnosti Heidenhain a také zevrubné srovnání tohoto systému se systémy jiných výrobců. V neposlední řadě budou v práci uvedeny také další produkty firmy Heidenhain a jejich možnost využití v praxi.Modern machine tools are equipped with control systems, which are the imaginary brain of the whole machine. These control systems are developed, further managed, and constantly innovated by many companies, so it is clear that there is a kind of competition in the field of control systems. The aim of this work is mainly to describe the possibilities of one of the greats among developers of control systems from the company Heidenhain and also a thorough comparison of this system with systems from other manufacturers. Last but not least, other Heidenhain products and their possibility of use in practice will be presented in the work.

    Proof-relevant resolution : the foundations of constructive proof automation

    Get PDF
    Dependent type theory is an expressive programming language. This language allows to write programs that carry proofs of their properties. This in turn gives high confidence in such programs, making the software trustworthy. Yet, the trustworthiness comes for a price: type inference involves an increasing number of proof obligations. Automation of this process becomes necessary for any system with dependent types that aims to be usable in practice. At the same time, implementation of automation in a verified manner is prohibitively complex. Sometimes, external solvers are used to aid the automation. These solvers may be based on classical logic and may not be themselves verified, thus compromising the guarantees provided by constructive nature of type theory. In this thesis, we explore the idea of proof relevant resolution that allows automation of type inference in type theory in a verifiable and constructive manner, hence to restore the confidence in programs and the trustworthiness of software. Technical content of this thesis is threefold. First, we propose a novel framework for proof-relevant resolution. We take two constructive logics, Horn-clause and hereditary Harrop formulae logics as a starting point. We formulate the standard big-step operational semantics of these logics. We expose their Curry-Howard nature by treating formulae of these logics as types and proofs as terms thus developing a theory of proof-relevant resolution. We develop small-step operational semantics of proof-relevant resolution and prove it sound with respect to the big-step operational semantics. Secondly, we demonstrate our approach on an example of type inference in Logical Framework (LF). We translate a type-inference problem in LF into resolution in proof-relevant Horn-clause logic. Such resolution provides, besides an answer substitution to logic variables, a proof term that captures the resolution tree. We interpret the proof term as a derivation of well-formedness judgement of the object in the original problem. This allows for a straightforward implementation of type checking of the resolved solution since type checking is reduced to verifying the derivation captured by the proof term. The theoretical development is substantiated by an implementation. Finally, we demonstrate that our approach allows to reason about semantic properties of code. Type class resolution has been well-known to be a proof-relevant fragment of Horn-clause logic, and recently its coinductive extensions were introduced. In this thesis, we show that all of these extensions amalgamate with the theoretical framework we introduce. Our novel result here is exposing that the coinductive extensions are actually based on hereditary Harrop logic, rather than Horn-clause logic. We establish a number of soundness and completeness results for them. We also discuss soundness of program transformation that are allowed by proof-relevant presentation of type class resolution

    Coinductive soundness of corecursive type class resolution

    Get PDF
    This work has been partially supported by the EU Horizon 2020 grant “RePhrase: Refactoring Parallel Heterogeneous Resource-Aware Applications - a Software Engineering Approach” (ICT-644235), by COST Action IC1202 (TACLe), supported by COST (European Cooperation in Science and Technology), and by EPSRC grant EP/K031864/1-2 “‘Coalgebraic Logic Programming for Type Inference”.Horn clauses and first-order resolution are commonly used for the implementation of type classes in Haskell. Recently, several core- cursive extensions to type class resolution have been proposed, with the common goal of allowing (co)recursive dictionary construction for those cases when resolution does not terminate. This paper shows, for the first time, that corecursive type class resolution and its recent extensions are coinductively sound with respect to the greatest Herbrand models of logic programs and that they are inductively unsound with respect to the least Herbrand models.Postprin

    Animation of the structural behavior of rod bolted joints

    Get PDF
    Tto prca sa zaober vyetrovan­m silovo deformaÄn©ho chovania predp¤tch ojniÄnch skrutiek, kinematiky a silov©ho p´sobenia v rmci kÄukov©ho mechanizmu tvordob©ho zihov©ho spaÄovacieho motora. Dan problematika je objasnen pomocou animci­, ktor© s urÄen© pre vzdelvacie Äely.This thesis deals with the investigation of the force-deformation behavior of prestressed crankshaft bolts, kinematics and dynamics within the crank mechanism of the four-stroke spark-ignition engine. This issue is illustrated by animations intended for educational purposes.

    Proof-relevant Horn clauses for dependent type inference and term synthesis

    Get PDF
    This work has been supported by the EPSRC grant “Coalgebraic Logic Programming for Type Inference” EP/K031864/1-2, EU Horizon 2020 grant “RePhrase: Refactoring Parallel Heterogeneous Resource Aware Applications - a Software Engineering Approach” (ICT-644235), and by COST Action IC1202 (TACLe), supported by COST (European Cooperation in Science and Technology).First-order resolution has been used for type inference for many years, including in Hindley-Milner type inference, type-classes, and constrained data types. Dependent types are a new trend in functional languages. In this paper, we show that proof-relevant first-order resolution can play an important role in automating type inference and term synthesis for dependently typed languages. We propose a calculus that translates type inference and term synthesis problems in a dependently typed language to a logic program and a goal in the proof-relevant first-order Horn clause logic. The computed answer substitution and proof term then provide a solution to the given type inference and term synthesis problem. We prove the decidability and soundness of our method.PostprintPeer reviewe
    corecore