Finding Regressions in Projects under Version Control Systems

Version Control Systems (VCS) are frequently used to support development of large-scale software projects. A typical VCS repository of a large project can contain various intertwined branches consisting of a large number of commits. If some kind of unwanted behaviour (e.g. a bug in the code) is found in the project, it is desirable to find the commit that introduced it. Such commit is called a regression point. There are two main issues regarding the regression points. First, detecting whether the project after a certain commit is correct can be very expensive as it may include large-scale testing and/or some other forms of verification. It is thus desirable to minimise the number of such queries. Second, there can be several regression points preceding the actual commit; perhaps a bug was introduced in a certain commit, inadvertently fixed several commits later, and then reintroduced in a yet later commit. In order to fix the actual commit it is usually desirable to find the latest regression point. The currently used distributed VCS contain methods for regression identification, see e.g. the git bisect tool. In this paper, we present a new regression identification algorithm that outperforms the current tools by decreasing the number of validity queries. At the same time, our algorithm tends to find the latest regression points which is a feature that is missing in the state-of-the-art algorithms. The paper provides an experimental evaluation of the proposed algorithm and compares it to the state-of-the-art tool git bisect on a real data set

Optimal Control of MDPs with Temporal Logic Constraints

In this paper, we focus on formal synthesis of control policies for finite Markov decision processes with non-negative real-valued costs. We develop an algorithm to automatically generate a policy that guarantees the satisfaction of a correctness specification expressed as a formula of Linear Temporal Logic, while at the same time minimizing the expected average cost between two consecutive satisfactions of a desired property. The existing solutions to this problem are sub-optimal. By leveraging ideas from automata-based model checking and game theory, we provide an optimal solution. We demonstrate the approach on an illustrative example.Comment: Technical report accompanying the CDC 2013 pape

Vendy

El trabajo de investigación Vendy es un modelo de negocio innovador, el cual consiste en implementar máquinas expendedoras de productos de primera necesidad para brindarles a los consumidores alternativas al momento de olvidarse cosas esenciales o productos necesarios ante alguna urgencia. Por ello, estarán ubicadas en los distritos más concurridos de la ciudad de Lima Metropolitana. La manera de estar en contacto con los consumidores será a través las redes sociales, el cual permitirá llegar a la población de la Lima Moderna donde se encuentran los consumidores potenciales. Los ingresos de la empresa se obtendrán ofreciendo artículos de primera necesidad, sobretodo en estos tiempos de pandemia, donde es necesario mantenernos protegidos y con todo el equipo necesario para cuidarnos. Algunos de los productos que se podrán encontrar son: mascarillas, alcohol, alcohol en gel, toallas húmedas, cepillo de dientes y pasta dental, desodorante, banditas, vendas, mini botiquín. Esto permitirá que los clientes que están en los alrededores de las máquinas dispensadoras ubicadas en puntos estratégicos donde por lo general hay oficinas y centros de estudio, si olvidan algún producto, puedan contar con productos de primera necesidad para atender urgencias personales a través de nuestras máquinas expendedoras la cual les facilitará la vida de forma inmediata, contando con diversos métodos de pago: efectivo y con POS.The research project Vendy is an innovative business model, which consists in the implementation of vending machines with necessity goods in order to provide these to consumers as alternatives whenever they forget essential items or necessary products due to an emergency. Therefore, they will be located in the busiest districts of the metropolitan Lima area. Social media is how we will be able to stay in touch with our potential consumers and the population of modern Lima. The company’s revenue will be generated through the provided products of necessity, specially during these times of pandemic, in which it is necessary to maintain protected and have all the needed equipment to do so. Some of the products that will be offered are masks, alcohol, alcohol in gel, wet wipes, toothbrushes, dental paste, deodorant, bandages and mini first aid kit. This will allow the customers who are located around the strategic locations of the vending machines, which will generally be found around offices and educational facilities, to be able to find these products whenever they forget an item. This situation is what will allow Vendy to facilitate their lives immediately meanwhile providing several payment methods like cash or POS (point of sale).Trabajo de investigació

Distributed Explicit Fair Cycle Detection: Set Based Approach

The fair cycle detection problem is at the heart of both LTL and fair CTL model checking. This paper presents a new distributed scalable algorithm for explicit fair cycle detection. Our method combines the simplicity of the distribution of explicitly presented data structure and the features of symbolic algorithm allowing for an ef\Thetacient parallelisation. If a fair cycle (i.e. counterexample) is detected, then the algorithm produces a cycle, which is in general shorter than that produced by depth-\Thetarst search based algorithms. Experimental results con- \Thetarm that our approach outperforms that based on a direct implementation of the best sequential algorithm