CLP Projection for Constraint Handling Rules

This paper introduces and studies the notion of CLP projection for Constraint Handling Rules (CHR). The CLP projection consists of a naive translation of CHR programs into Constraint Logic Programs (CLP). We show that the CLP projection provides a safe operational and declarative approximation for CHR programs. We demónstrate moreover that a confluent CHR program has a least model, which is precisely equal to the least model of its CLP projection (closing henee a ten year-old conjecture by Abdenader et al.). Finally, we illustrate how the notion of CLP projection can be used in practice to apply CLP analyzers to CHR. In particular, we show results from applying AProVE to prove termination, and CiaoPP to infer both complexity upper bounds and types for CHR programs.

Damage mechanisms in the handling of fruits

The recognition of an increasing and worldwide demand for high quality in fruits and vegetables has grown in recent years. Evidence of severe problems of mechanical damage is increasing, and this is affecting the trade of fruits in European and other countries. The potential market for fresh high-quality vegetables and fruits remains restricted by the lack of quality of the majority of products that reach consumers; this is the case for local as well as import/export markets, so a reduction in the consumption of fresh fruits in favour of other fixed-quality products (dairy in particular) may become widespread. In a recent survey (King, 1988, cited in Bellon, 1989), it appears that, for the moment, one third of the surveyed consumers are still continuing to increase their fresh produce consumption. The factors that appear as being most important in influencing the shopping behaviour of these consumers are taste/flavour, freshness/ripeness, appealing look, and cleanliness. Research on mechanical damage in fruit and vegetables has been underway for several years. The first research made on physical properties of fruits was in fact directed towards analysing the response to slow or rapid loading of selected fruits (Fridley et al, 1968; Horsefield et al., 1972). From that time on, research has expanded greatly, and different aspects of the problem have been approached. These include applicable mechanical models for the contact problem, the response of biological tissues to loading, devices for detecting damage causes in machines and equipment, and procedures for sensing bruises in grading and sorting. This chapter will be devoted to the study of actual research results relative to the cause and mechanisms of mechanical damage in fruits (secondarily in vegetables), the development of bruises in these commodities, the models that have been used up to now, and the different factors which have been recognized as influencing the appearance and development of mechanical damage in fruits. The study will be focused mainly on contact-damage - that is, slow or rapid loads applied to the surface of the products and causing bruises. (A bruise is defined as an altered volume of fruit tissues below the skin that is discoloured and softened.) Other types of mechanical damage, like abrasion and scuffing, punctures and cuts, will be also mentioned briefly.

Improving the competitiveness of the Spanish port system by optimising the cargo handling service

Port services, and in particular the cargo handling service, are responsible for the greatest share of costs incurred during the passage of cargo through a port. The provision of these services reliably and efficiently is crucial in a sector in which there is great opacity. This study has provided the responsible administration ? the Port Authority ? with a tool enabling objective decision making both when it comes to issuing the corresponding licenses and during the period of service provision. Furthermore, we have proposed a series of measures whose application would improve the conditions of service provision and reduce the costs incurred by the passage of cargo through the port.

Tomatoes for processing in the 90's: Postharvest handling.

Processing tomato industry has a high potential in Spain. Variety testing and mechanization studies and applications have been performed during the last 15 years. Many factors affect the quality and product losses during post-harvest handling which may be classified as: main or external factors: those related to the systems, procedures and devices; and fruit factors: those related to fruit properties. A research project is being carried on in the area of Vegas del Guadiana (Badajoz, Spain) to study these factors and to estimate costs, and to develop improved post-harvest handling practices.

Damage Mechanisms in the Handling of fruits.

Recent findings on the importance of losses due to damage incidence, on causes and on mechanisms of damage in fruits are reviewed and discussed. Incidence of damage in different fruits in some European markets has been -proved to be very high. Structure of fruit flesh and skin (hystology) is of foremost importance in the response of fruits to impacts and to compression. Continuous variation of fruit compositional and structural characteristics during maturation has to be taken into consideration when studying damage susceptibility.

Use of electronic fruits to evaluate fruit damage along the handling process.

Two electronic fruits (SEP-1, Simulated Electronic Product, developed in Scotland, and Techmark IS-100, Instrumented Sphere, developed in USA) have been compared in laboratory tests and then used to evaluate handling operations, in several cooperatives of two areas of Spain: Lérida (pome fruits) and Valencia (stone fruits). Advantages of each device were evaluated. Harvest, mechanical bin unloading, and grading line transfers and sizers were identified as operations causing fruit damage.

Neural bruise prediction models for fruit handling and machinery evaluation.

Some neural bruise prediction models have been implemented in the laboratory, for the most traded fruit species and varieties, allowing the prediction of the acceptability or rejectability for damages, with respect to the EC Standards. Different models have been built for both quasi-static (compression) and dynamic (impact) loads covering the whole commercial ripening period of fruits. A simulation process has been developed gathering the information on laboratory bruise models and load sensor calibrations for different electronic devices (IS-100 and DEA-1, for impact and compression loads respectively). Some evaluation methodology has been designed gathering the information on the mechanical properties of fruits and the loading records of electronic devices. The evaluation system allows to determine the current stage of fruit handling process and machinery.

Effects of precooling and degreening treatments on the susceptibility of peach and citrus to handling damage.

Mechanical damage to fruits results from a combination of fruit properties and of damage inflicting effects by the handling equipment. Treatments were applied to fruits which affect mechanical damage susceptibility: precooling for stone fruits and degreening to citrus fruits. Laboratory tests (compression, impact, tumbling, abrasion) and field tests (damage in the handling lines) were applied to (3) peach, (2) apricot, (2) orange and (1) lemon varieties. Hydroor-air-cooling influence positively peach and apricot firmness and cause a significant reduction in: number of bruised fruits, and size of visible bruise, when combined with a low level of loading during handling. Degreening also affects the resistance of citrus fruits to handling, when compared to green fruits.

Models for the prediction of handling damage in citrus and peaches grading lines, related to their physical properties.

Fruit damage during harvesting and handling is a standing problem, particularly for susceptible fruits like peaches and apricots. The resulting mechanical damage is a combination of fruit properties and damage inflicting effects due to procedures and to the equipment. Nine packing lines in the region of Murcia (SE Spain) have been tested with the aid of two different-size electronic fruits IS-100. Probabilities of impacts above three preset thresholds (50 g's, 100 g's and 150 g's) were calculated for each transfer point. Interaction fruit-packing line tests have been also performed in order to study the real incidence of packing lines on natural produce: apricots (1 variety), peaches (3 v.), lemons (1 v.) and oranges (3 v.). Bruises of handled and not handled samples of fruits were compared.

The Imaging and Slitless Spectroscopy Instrument for Surveys (ISSIS): expected radiometric performance, operation modes and data handling

ISSIS is the instrument for imaging and slitless spectroscopy on-board WSO-UV. In this article, a detailed comparison between ISSIS expected radiometric performance and other ultraviolet instruments is shown. In addition, we present preliminary information on the performance verification tests and on the foreseen procedures for in-flight operation and data handling.

Simulating the remote handling of the blanket segments in DEMO fusion reactor with thermo-mechanical meshfree multibody dynamics

The present study shows a first approach to the simulation of the remote handling oper- ation which takes into account the thermal and flexible behavior of the blanket segments and its implications on the remote handling equipment, in order to validate and improve its design.

Anchor Handling & Tug Supply Vessel

Buque para el apoyo de instalaciones offshore, ya sea como suministro o para desempeñar un papel más específico como el remolque y posicionamiento de plataformas o artefactos marinos. Se trata de un buque AHTS con un tiro a punto fijo de 250 toneladas, 4.500 toneladas de peso muerto, capacidad de acomodación para 45 personas y propulsión diésel con dos hélices de paso controlable. Cuenta con una capacidad de cubierta de 750 m2, una grúa principal de 100 toneladas y sistema de posicionamiento dinámico DYNPOS-AUTRO.