Current web browsers are complex, have enormous trusted computing bases, and provide attackers with easy access to computer systems. This makes web browser security a difficult issue that increases in importance as more and more applications move to the web. Our approach for this challenge is to design and build a correct-by-construction web browser, called IBOS, that consists of multiple concu...

We present a modular approach to defining logics for a wide variety of state-based systems. The systems are modelled as coalgebras, and we use modal logics to specify their observable properties. We show that the syntax, semantics and proof systems associated to such logics can all be derived in a modular fashion. Moreover, we show that the logics thus obtained inherit soundness, completeness a...

let $g$ be a connected graph of order $3$ or more and $c:e(g)rightarrowmathbb{z}_k$‎ ‎($kge 2$) a $k$-edge coloring of $g$ where adjacent edges may be colored the same‎. ‎the color sum $s(v)$ of a vertex $v$ of $g$ is the sum in $mathbb{z}_k$ of the colors of the edges incident with $v.$ the $k$-edge coloring $c$ is a modular $k$-edge coloring of $g$ if $s(u)ne s(v)$ in $mathbb{z}_k$ for all pa...

We propose a set of abstractions to modularize implementation of Bayesian inference algorithms. We provide a proof-of-concept implementation as a Haskell library and demonstrate on several examples how it simplifies implementation of Monte Carlo algorithms. Our technique is based on a method for modular construction of interpreters using monad transformers and is applicable generically to proba...

The JastAdd system enables modular specifications of extensible compiler tools and languages. Java has been extended with the Rewritable Circular Reference Attributed Grammars formalism that supports modularization and extensibility through several synergistic mechanisms. Object-orientation and static aspect-oriented programming are combined with declarative attributes and context-dependent rew...

We propose a modular reinforcement learning algorithm which decomposes a Markov decision process into independent modules. Each module is trained using Sarsa(λ). We introduce three algorithms for forming global policy from modules policies, and demonstrate our results using a 2D grid world.

environments: Since the abstract counterpart for addresses are symbolic variables (or nodes) in shape graphs, an abstract environment E can simply be a function mapping program variables to nodes, that is, E ∈ E =X→V. Now, the memory abstract domainM is defined byM = E× (H ⇒ N ), and its concretization γM :M ♯ → P(E×H) can be defined as follows: γM(E ,(σ ,ν)) def = {(ν ◦E,σ) | (σ ,ν) ∈ γH(σ ) a...

We show the benefits of applying modular monadic semantics to compiler construction. Modular monadic semantics allows us to define a languagewith a rich set of features from reusable building blocks, and use program transformation and equational reasoning to improve code. Compared to denotational semantics, reasoning in monadic style offers the added benefits of highly modularized proofs and mo...

Modular towers, a notion due to M. Fried, are towers of Hurwitz spaces, with levels corresponding to the characteristic quotients of the p-universal Frattini cover of a fixed finite group G (with p a prime divisor of |G|). The tower of modular curves X1(pn) (n>0) is the original example: the group G is then the dihedral group Dp. There are diophantine conjectures on modular towers, inspired by ...