Declarative visitors to ease fine-grained source code mining with full history on billions of AST nodes

Software repositories contain a vast wealth of information about software development. Mining these repositories has proven useful for detecting patterns in software development, testing hypotheses for new software engineering approaches, etc. Specifically, mining source code has yielded significant insights into software development artifacts and processes. Unfortunately, mining source code at a large-scale remains a difficult task. Previous approaches had to either limit the scope of the projects studied, limit the scope of the mining task to be more coarse-grained, or sacrifice studying the history of the code due to both human and computational scalability issues. In this paper we address the substantial challenges of mining source code: a) at a very large scale; b) at a fine-grained level of detail; and c) with full history information. To address these challenges, we present domain-specific language features for source code mining. Our language features are inspired by object-oriented visitors and provide a default depth-first traversal strategy along with two expressions for defining custom traversals. We provide an implementation of these features in the Boa infrastructure for software repository mining and describe a code generation strategy into Java code. To show the usability of our domain-specific language features, we reproduced over 40 source code mining tasks from two large-scale previous studies in just 2 person-weeks. The resulting code for these tasks show between 2.0x--4.8x reduction in code size. Finally we perform a small controlled experiment to gain insights into how easily mining tasks written using our language features can be understood, with no prior training. We show a substantial number of tasks (77%) were understood by study participants, in about 3 minutes per task

Distributed Supervisory Control of Discrete-Event Systems with Communication Delay

This paper identifies a property of delay-robustness in distributed supervisory control of discrete-event systems (DES) with communication delays. In previous work a distributed supervisory control problem has been investigated on the assumption that inter-agent communications take place with negligible delay. From an applications viewpoint it is desirable to relax this constraint and identify communicating distributed controllers which are delay-robust, namely logically equivalent to their delay-free counterparts. For this we introduce inter-agent channels modeled as 2-state automata, compute the overall system behavior, and present an effective computational test for delay-robustness. From the test it typically results that the given delay-free distributed control is delay-robust with respect to certain communicated events, but not for all, thus distinguishing events which are not delay-critical from those that are. The approach is illustrated by a workcell model with three communicating agents

Circular Building Design for the Infill Domain: Materialisation, and Value Network study of the Niaga ECOR Panel innovation

Circular Building gained traction during the past decade in the Netherlands. Circular Building (CB) is rooted in concepts such as Circular Economy and Cradle-to-Cradle®, accentuating closing and continuing of material flows to establish sustainable resource cycles. CB implies that buildings and building components are designed to retain value, tailored for specific service lives and responsive to changing needs. This way, wasting of buildings and building components can be reduced or avoided. This paper revolves around circular materialisation and operation of building infill, such as furniture, partitions, and kitchens. The short to medium-long material cycles usually associated with those components provide potential benefits for circular resource management. The paper comprises a study into materialisation and operational performance of the Niaga ECOR Panel (NEP): an innovative cellulose board product. NEP aims to offer a healthy and circular alternative for conventional linear board products and value chains, adhering to multiple Sustainable Development Goals, notably: SDG11 (Sustainable Cities and Communities) and SDG12 (Responsible Production and Consumption). The study follows Circ-Flex assessment guidelines, anticipating operational performance through the supply, use, and reverse-supply chain. The findings indicate that the intrinsic properties of the NEP can enable circular infill value models, provided that networked actors remain aligned

Circular Building Design for the Infill Domain: Materialisation, and Value Network study of the Niaga ECOR Panel innovation

Circular Building gained traction during the past decade in the Netherlands. Circular Building (CB) is rooted in concepts such as Circular Economy and Cradle-to-Cradle®, accentuating closing and continuing of material flows to establish sustainable resource cycles. CB implies that buildings and building components are designed to retain value, tailored for specific service lives and responsive to changing needs. This way, wasting of buildings and building components can be reduced or avoided. This paper revolves around circular materialisation and operation of building infill, such as furniture, partitions, and kitchens. The short to medium-long material cycles usually associated with those components provide potential benefits for circular resource management. The paper comprises a study into materialisation and operational performance of the Niaga ECOR Panel (NEP): an innovative cellulose board product. NEP aims to offer a healthy and circular alternative for conventional linear board products and value chains, adhering to multiple Sustainable Development Goals, notably: SDG11 (Sustainable Cities and Communities) and SDG12 (Responsible Production and Consumption). The study follows Circ-Flex assessment guidelines, anticipating operational performance through the supply, use, and reverse-supply chain. The findings indicate that the intrinsic properties of the NEP can enable circular infill value models, provided that networked actors remain aligned.Climate Design and Sustainabilit

Networks of communicating processes and their (de-)composition

In this paper we sketch a general framework within which a study of networks of processes can be conducted. It is based upon the mathematical technique to abstract from irrelevant detail. We start out with a large class of objects and some operations upon them. Depending upon a correctness criterion to be imposed, some of these objects turn out to be equivalent. The resulting space of equivalence classes and operations upon them is, under certain conditions, the (fully) abstract space of interest for that particular correctness concern. We use this approach to study networks for which we assume the communications to be asymmetric and asynchronous. We impose the correctness criterion of absence of computation interference. The resulting abstract space turns out to be the space of delay-insensitive specifications. As operator we study composition of networks. The composition operator on the resulting space is shown to have a surprisingly simple factorization property, the prove of which turns out to be very simple due to the approach taken