Comparing metaheuristic algorithms for error detection in Java programs

Chicano, F., Ferreira M., & Alba E. (2011). Comparing Metaheuristic Algorithms for Error Detection in Java Programs. In Proceedings of Search Based Software Engineering, Szeged, Hungary, September 10-12, 2011. pp. 82–96.Model checking is a fully automatic technique for checking concurrent software properties in which the states of a concurrent system are explored in an explicit or implicit way. The main drawback of this technique is the high memory consumption, which limits the size of the programs that can be checked. In the last years, some researchers have focused on the application of guided non-complete stochastic techniques to the search of the state space of such concurrent programs. In this paper, we compare five metaheuristic algorithms for this problem. The algorithms are Simulated Annealing, Ant Colony Optimization, Particle Swarm Optimization and two variants of Genetic Algorithm. To the best of our knowledge, it is the first time that Simulated Annealing has been applied to the problem. We use in the comparison a benchmark composed of 17 Java concurrent programs. We also compare the results of these algorithms with the ones of deterministic algorithms.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish Ministry of Science and Innovation and FEDER under contract TIN2008-06491-C04-01 (the M∗ project) and the Andalusian Government under contract P07-TIC-03044 (DIRICOM project)

Disclosure and liquidity

The purpose of this paper is to test empirically the relationship between two important concepts: disclosure and liquidity. Using a sample of Spanish quoted firms between 1994 and 2000 we show that the estimation of the relationship between disclosure and liquidity depends crucially on two factors: a) the multidimensionality of the concept of liquidity; b) the use of an econometric methodology that deals properly with the features of the sample used. However the use of the Amihud (2002) illiquidity measure provides evidence in favour of a positive relationship between disclosure and liquidity

National innovation system, competitiveness and economic growth

Differences in income-elasticities of imports and exports among countries bring about distinct degrees of external constraints to growth. This argument has been pointed out by Prebisch and by authors in the Kaldorian tradition. Prebisch’s explanations for this phenomenon relate to the differences in international insertion between agrarian / peripheral and industrial / central economies. Kaldorian authors, in turn, refer to Prebisch only to explain why such elasticities differ between products and between countries. However, even after undergoing industrialization processes, several economies still face external constraints to growth. The aim of this paper is to explain differences in trade elasticities among industrial economies. Therefore, it intends to demonstrate, by using the Neo-Schumpeterian literature, the causal relations between the development of a National Innovation System, the differences in income-elasticities of imports and exports, the degree of competitiveness and the degree of external vulnerability of an economy.national innovation system, competitiveness, external vulnerability

Electromechanical device for temperature control of internal combustion engines

Internal combustion engines are the most commonly used engines in the automotive world. However, these engines lack an overheating prevention system against cooling system failures when they exceed their normal operating temperature. Less experienced drivers (users) usually do not notice overheating until the engine stops, generating economic expenses in engine repairs. As such, this paper describes the design and construction of an electromechanical device to prevent engine overheating. This device is installed in a vehicle and operates independently from the electronic control unit (ECU); it records the coolant temperature and controls air admission to the engine of the vehicle in which it is installed. In addition, a new Arduino-based card will receive signals from a temperature sensor as input and process them according to its programming. Then, it will send signal outputs to the actuators: a servomotor, monitor, LED display, and buzzer. To control the intake flow, a butterfly valve is used with the servomotor. This valve partially or totally restricts the engine airflow, based on the temperature programmed for the Arduino, thus protecting the engine from overheating

A New Time-Dependent Limit-Equilibrium Model to Understand Progressive Failure in Bedrock Slopes on the Grimsel Pass

Rockfalls can have serious consequences. Therefore, it is important to understand the processes to apply security measures. Limit equilibrium methods (LEM) are models used due to their simplicity and reliability to evaluate rock mass instabilities. Despite the advantages, LEMs assume temporally invariable conditions. The objective is the implementation of a temporally varying condition (progressive tensile edge cracking) in the LEM with the aim of performing a time-dependent analysis. The code combines LEM with crack growth theory to evaluate growth evolution. When a crack begins to propagate, it is selected between the Paris or Charles law of crack growth, choosing the fastest. During propagation, the code records the crack opening, length, iteration, and propagation time until it reaches a critical state. The retrospective analysis used a digital elevation model (DEM) of the Grimsel Pass (Switzerland). The model results help to understand the evolution of tensile crack propagation and new modules can be added to the model. However, the model has limitations and the results should be carefully evaluated.Los desprendimientos de rocas pueden tener graves consecuencias. Por ello es importante comprender los procesos para aplicar las medidas de seguridad Los métodos de equilibrio límite (LEM) son modelos utilizados debido a su sencillez y fiabilidad para evaluar inestabilidades del macizo rocoso. A pesar las ventajas, los LEM suponen condiciones invariables temporalmente. El objetivo es la implementación de una condición temporalmente variante (fisura progresiva de borde por tracción) en el LEM con el objetivo de realizar un análisis dependiente del tiempo. El código combina LEM con la teoría de crecimiento de grietas para evaluar la evolución del crecimiento. Cuando una grieta comienza a propagarse, se selecciona entre la ley de crecimiento de grieta de París o Charles, eligiendo la más rápida. Durante la propagación, el código registra la apertura de la grieta, la longitud, la iteración y el tiempo de propagación hasta que alcanza un estado crítico. El análisis retrospectivo se usó un modelo digital de elevación (DEM) del abra de Grimsel (Suiza). Los resultados del modelo ayudan a comprender la evolución de la propagación de la grieta de tracción y al modelo se puede añadir nuevos módulos. Sin embargo, el modelo tiene limitaciones y los resultados deben evaluarse cuidadosamente.Los desprendimientos de rocas pueden tener graves consecuencias. Por ello es importante comprender los procesos para aplicar las medidas de seguridad. Los métodos de equilibrio límite (LEM) son modelos utilizados debido a su sencillez y fiabilidad para evaluar inestabilidades del macizo rocoso. A pesar las ventajas, los LEM suponen condiciones invariables temporalmente. El objetivo es la implementación de una condición temporalmente variante (fisura progresiva de borde por tracción) en el LEM con el objetivo de realizar un análisis dependiente del tiempo. El código combina LEM con la teoría de crecimiento de grietas para evaluar la evolución del crecimiento. Cuando una grieta comienza a propagarse, se selecciona entre la ley de crecimiento de grieta de París o Charles, eligiendo la más rápida. Durante la propagación, el código registra la apertura de la grieta, la longitud, la iteración y el tiempo de propagación hasta que alcanza un estado crítico. El análisis retrospectivo usó un modelo digital de elevación (DEM) del abra de Grimsel (Suiza). Los resultados del modelo ayudan a comprender la evolución de la propagación de la grieta de tracción y al modelo se puede añadir nuevos módulos. Sin embargo, el modelo tiene limitaciones y los resultados deben evaluarse cuidadosamente.Tesi