A simple optimised search heuristic for the job-shop scheduling problem

This paper presents a simple Optimised Search Heuristic for the Job Shop Scheduling problem that combines a GRASP heuristic with a branch-and-bound algorithm. The proposed method is compared with similar approaches and leads to better results in terms of solution quality and computing times.

How to recognize opportunities: Heterarchical search in a Wall Street trading room

Our task in this paper is to analyze the organization of trading in the era of quantitativefinance. To do so, we conduct an ethnography of arbitrage, the trading strategy that bestexemplifies finance in the wake of the quantitative revolution. In contrast to value andmomentum investing, we argue, arbitrage involves an art of association - the constructionof equivalence (comparability) of properties across different assets. In place of essentialor relationa l characteristics, the peculiar valuation that takes place in arbitrage is based on an operation that makes something the measure of something else - associating securities to each other. The process of recognizing opportunities and the practices of making novel associations are shaped by the specific socio-spatial and socio-technical configurations of the trading room. Calculation is distributed across persons and instruments as the trading room organizes interaction among diverse principles of valuation.

Non-stationary job search when jobs are not forever: A structural estimation

This paper considers a job search model where the environment is notstationary along the unemployment spell and where jobs do not lastforever. Under this circumstance, reservation wages can be lower thanwithout separations, as in a stationary environment, but they can alsobe initially higher because of the non-stationarity of the model. Moreover,the time-dependence of reservation wages is stronger than with noseparations. The model is estimated structurally using Spanish data forthe period 1985-1996. The main finding is that, although the decrease inreservation wages is the main determinant of the change in the exit ratefrom unemployment for the first four months, later on the only effect comesfrom the job offer arrival rate, given that acceptance probabilities areroughly equal to one.

Unemployment insurance with endogenous search intensity and precautionary saving

A welfare analysis of unemployment insurance (UI) is performed in a generalequilibrium job search model. Finitely-lived, risk-averse workers smooth consumption over time by accumulating assets, choose search effort whenunemployed, and suffer disutility from work. Firms hire workers, purchasecapital, and pay taxes to finance worker benefits; their equity is the assetaccumulated by workers. A matching function relates unemployment, hiringexpenditure, and search effort to the formation of jobs. The model is calibrated to US data; the parameters relating job search effort to the probability of job finding are chosen to match microeconomic studies ofunemployment spells. Under logarithmic utility, numerical simulation shows rather small welfaregains from UI. Even without UI, workers smooth consumption effectivelythrough asset accumulation. Greater risk aversion leads to substantiallylarger welfare gains from UI; however, even in this case much of its welfareimpact is due not to consumption smoothing effects, but rather to decreased work disutility, or to a variety of externalities.

Job search and asset accumulation under borrowing constraints

In this paper I show how borrowing constraints and job search interact.I fit a dynamic model to data from the National Longitudinal Survey(1979-cohort) and show that borrowing constraints are significant. Agentswith more initial assets and more access to credit attain higher wagesfor several periods after high school graduation. The unemployed maintaintheir consumption by running down their assets, while the employed saveto buffer against future unemployment spells. I also show that, unlikein models with exogenous income streams, unemployment transfers, byallowing agents to attain higher wages do not 'crowd out' but increasesaving.

Student experiences in a course blended learning

Fascination is a project for design students, developed jointly by the Technical University of Catalonia (UPC) and the University of Technology Thonburi (KMUTT), which works with two groups of students, one group of participants in Spain and another group in Thailand where, hands-on activities, a range of technologies are used to prepare students for the lessons, through learning activities and content. This research paper presents the test of both a general model and a tool for measuring the participants’ experiences in a course that uses a blended learning methodology, with the aim of collecting empirical evidence to justify the effort of applying this methodology, based on the participants’ satisfaction. The procedure used in the conceptualization of the survey, the generation of topics, the collection of data, and the validation of the scale of various items are described here. The information, provided by the 26 people surveyed about the course and the virtual environment that was used, was analyzed to measure their perceptions and explore possible relations. Finally the conclusions of the research and the future work are presented.

El Misterio de la biblioteca Mil.lènium o cómo promover relaciones colaborativas desde la participación del alumnado = The Mystery of the Mil.lènium Library: How to Promote Collaborative Relationships Through Student Participation

La pedagogía crítica acentúa la falta de neutralidad de la escuela respecto a las relaciones de poder que existen en la sociedad. Su propuesta consiste en modificar las relaciones de poder en el aula en el sentido de transformar las relaciones coercitivas –las que reproducen las relaciones existentes– en relaciones colaborativas partiendo del reconocimiento y la participación de los alumnos en las actividades escolares. Desde esta perspectiva, uno de los objetivos de las actividades es que los niños produzcan «textos identitarios», entendidos como artefactos que los alumnos se pueden apropiar para promover su desarrollo cognitivo. El artículo muestra el trabajo educativo integrado desde Educación Infantil hasta 6.º de Primaria de una escuela de la provincia de Girona en la que el 97% de los alumnos es de origen extranjero y cuyo propósito es incrementar las habilidades lingüísticas orales y escritas en la lengua escolar, así como la utilización de otros lenguajes multimedia. La unidad didáctica consiste en la elaboración de un cuento a lo largo de un curso escolar por parte de todo el alumnado con la ayuda de los profesores, de dos autores y de tres ilustradores. Cada ciclo escolar decide los personajes y el escenario y explicita textualmente el transcurso de la acción. Los ilustradores producen las imágenes y los autores posibilitan la transición de aquello que ha elaborado un ciclo al producto del siguiente. La actividad basada en la participación y la utilización de procedimientos democráticos de decisión se inserta en la propuesta educativa y lingüística de la escuela, así como en sus concreciones curriculares. Los resultados muestran que los textos construidos por los niños se apoyan en sus «fondos de conocimiento» sociales y familiares y constituyen una fuente de progreso en la consecución de las competencias básicas y en la construcción de valores democráticos

A Model for Improving the Quality of Student Internship Placements in Engineering Degrees

Work Internship Placements (WIP) is a new and transversal enterprise internships programme, which is focused on quality improvement, academic control and satisfaction of collaborating enterprises. This programme is addressed to the engineering students of the PolytechnicSchool at the University of Girona (UdG) in Spain. The fundamental WIP infrastructure combines a web-based intranet platform, that provides a complete set of WIP tools, with a protocol of procedures and tasks that are observed and followed at all internship stages by every participating agent, i.e. enterprises, students, coaching professors and administrative staff. Our new programme is centered on a broader, more holistic internship placement procedure than the traditional “career and academic goals” approach. The WIP programme has been found to be a valuable asset in addressing enterprise and student needs in the experiential project

A search for microquasar candidates at low galactic latitudes

Recent studies of relativistic jet sources in the Galaxy, also known as microquasars, have been very useful in trying to understand the accretion/ejection processes that take place near compact objects. However, the number of sources involved in such studies is still small. In an attempt to increase the number of known microquasars we have carried out a search for new Radio Emitting X-ray Binaries (REXBs). These sources are the ones to be observed later with VLBI techniques to unveil their possible microquasar nature. To this end, we have performed a cross-identification between the X-ray ROSAT all sky survey Bright Source Catalog (RBSC) and the radio NRAO VLA Sky Survey (NVSS) catalogs under very restrictive selection criteria for sources with |b|<5 degrees. We have also conducted a deep observational radio and optical study for six of the selected candidates. At the end of this process two of the candidates appear to be promising, and deserve additional observations aimed to confirm their proposed microquasar nature.

Search for very high energy gamma-ray emission from pulsar-pulsar wind nebula systems with the MAGIC telescope

The MAGIC collaboration has searched for high-energy gamma-ray emission of some of the most promising pulsar candidates above an energy threshold of 50 GeV, an energy not reachable up to now by other ground-based instruments. Neither pulsed nor steady gamma-ray emission has been observed at energies of 100 GeV from the classical radio pulsars PSR J0205+6449 and PSR J2229+6114 (and their nebulae 3C58 and Boomerang, respectively) and the millisecond pulsar PSR J0218+4232. Here, we present the flux upper limits for these sources and discuss their implications in the context of current model predictions.

Search for nonstandard Higgs boson in diphoton events at p anti-p collisions

We estimate the attainable limits on the coupling of a nonstandard Higgs boson to two photons taking into account the data collected by the Fermilab collaborations on diphoton events. We based our analysis on a general set of dimension-6 effective operators that give rise to anomalous couplings in the bosonic sector of the standard model. If the coefficients of all blind operators have the same magnitude, indirect bounds on the anomalous triple vector-boson couplings can also be inferred, provided there is no large cancellation in the Higgs-gamma-gamma coupling.

Leaving the cave in search of life (A Platonic reading of R. Sirera's La caverna (The Cave)

The aim of this article is to show how a contemporary playwright thinks once more of the Platonic image of the cave in order to reflect on the necessary existential journey of men and women as in the case of a Bildungsroman. Sooner or later men and women must abandon the protection that any sort of cavern such as home, the family garden or family itself can offer. In spite of writing from a by no means idealistic or metaphysical point of view, thanks to R. Sirera and to the very applicability of Platonic images, Plato becomes once again a classical reference which is both useful and even unavoidable if one bears in mind the Platonic origin of all the literary caverns.

Optimal network topologies for local search with congestion

The problem of searchability in decentralized complex networks is of great importance in computer science, economy, and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and we obtain expressions for the average search cost both in the presence and the absence of congestion. This formalism is used to obtain optimal network structures for a system using a local search algorithm. It is found that only two classes of networks can be optimal: starlike configurations, when the number of parallel searches is small, and homogeneous-isotropic configurations, when it is large.

La Participación de los estudiantes en la universidad: dificultades percibidas y propuestas de mejora = Student participation in the university: perceived problems and proposals for improvement

Este artículo se centra en el análisis de la participación de los estudiantes en el gobierno de la universidad y muestra específicamente las principales dificultades que hay para ella y las propuestas que pueden facilitar la implicación de los estudiantes en el funcionamiento de las universidades. A partir de una investigación desarrollada durante los cursos 2007-08 y 2008-09, en la que se utilizaron cuestionarios y grupos de discusión con estudiantes y entrevistas dirigidas al profesorado, se obtiene información sobre los principales obstáculos para la participación estudiantil. El estudio realizado muestra que, de acuerdo con la tónica general reflejada en otras investigaciones sobre esta misma temática en nuestro contexto, la participación de los estudiantes en los distintos estamentos universitarios es escasa. Ahora bien, la metodología seguida en esta investigación permite contrastar las opiniones de los estudiantes con las percepciones del profesorado y obtener así matices significativos que muestran las principales direcciones que hay que tomar para facilitar un cambio de orientación en el asunto. Los cambios que debemos emprender están relacionados no solo con la mejora de los mecanismos de información acerca de los canales de participación, sino también con el replanteamiento de los procesos participativos por parte de la universidad, así como del papel del profesorado y, específicamente, de los coordinadores de los órganos de gestión más próximos a los estudiantes. En las conclusiones del documento se presentan las propuestas de mejora dirigidas a potenciar la implicación de los estudiantes en el funcionamiento universitario. Entre ellas se apuntan las siguientes: mejorar la información y los canales de comunicación con los estudiantes, mejorar los procesos electorales, ofrecer formación a los estudiantes para la participación y formación al profesorado acerca de las metodologías, recursos e instrumentos que pueden repercutir en la motivación de los estudiantes

Effects of math anxiety on student success in higher education

This study examines whether math anxiety and negative attitudes toward mathematics have an effect on university students" academic achievement in a methodological course forming part of their degree. A total of 193 students were presented with a math anxiety test and some questions about their enjoyment, self-confidence and motivation regarding mathematics, and their responses were assessed in relation to the grades they had obtained during continuous assessment on a course entitled"Research Design". Results showed that low performance on the course was related to math anxiety and negative attitudes toward mathematics. We suggest that these factors may affect students" performance and should therefore be taken into account in attempts to improve students" learning processes in methodological courses of this kind.