Proving termination through conditional termination

We present a constraint-based method for proving conditional termination of integer programs. Building on this, we construct a framework to prove (unconditional) program termination using a powerful mechanism to combine conditional termination proofs. Our key insight is that a conditional termination proof shows termination for a subset of program execution states which do not need to be considered in the remaining analysis. This facilitates more effective termination as well as non-termination analyses, and allows handling loops with different execution phases naturally. Moreover, our method can deal with sequences of loops compositionally. In an empirical evaluation, we show that our implementation VeryMax outperforms state-of-the-art tools on a range of standard benchmarks.Peer ReviewedPostprint (author's final draft

Priorització de comandes a Sap Business One

La gestió dels estocs és un tema important per les empreses. Disposar de molt estoc per un nombre gran de productes que asseguri poder satisfer les demandes diàries pot tenir un alt cost d'emmagatzematge i altres costos associats especialment en productes que caduquen i en moments en que hi ha grans fluctuacions en la demanda. Les empreses intenten aconseguir un equilibri en la gestió dels estocs per aconseguir la màxima competitivitat intentant servir als seus clients en un temps adequat i evitant alhora grans costos d'emmagatzematge. Quan l'estoc és insuficient per cobrir les demandes diàries, cal seleccionar quines de les comandes rebudes es serveixen i quines queden a l'espera de l'arribada de més estoc. L'empresa que ha sol·licitat aquest projecte vol prioritzar les comandes a servir tenint en compte les característiques dels clients i de la pròpia comanda. Així doncs, el problema que se'ns planteja és el següent: A partir d'un conjunt de comandes i unes restriccions d'estoc dels productes que hi apareixen, es vol prioritzar l'assignació de l'estoc disponible sobre el conjunt de comandes. Aquesta priorització ve marcada per uns criteris parametritzables els quals fan referència al tipus de client que fa la comanda, així com a algun atribut de la pròpia comanda. En aquest projecte, es fa un estudi sobre quina tècnica és la més adequada per a resoldre el problema pel tipus de comandes i perfil de clients de l'empresa, considerant des d'algoritmes que permeten trobar una solució aproximada fins a algoritmes que troben una solució òptima. La tècnica escollida és la que s'implementa al sistema SAP de l'empresa. A partir dels criteris de priorització escollits, es realitza una puntuació de les comandes i s'obté la selecció de comandes a servir que aconsegueix la millor puntuació satisfent les restriccions d'estocs. La solució genera una distribució dels estocs dels magatzems per cadascun dels productes de les comandes seleccionades.Stock management is an important issue for companies. Holding a lot of stock for a large number of products to ensure that daily demands can be met can have high storage and other associated costs, especially for products that expire and at times when there are large fluctuations in demand. Companies try to strike a balance in stock management to achieve maximum competitiveness by trying to serve their customers in a timely manner while avoiding high storage costs. When the stock is insufficient to cover the daily demands, it is necessary to select which of the received orders are served and which are left to await the arrival of more stock. The company that has requested this project wishes to prioritize the orders to be served, taking into account the characteristics of the customers and of the order itself. Therefore, the problem that arises is the following:Starting from a set of orders and some stock restrictions of the products, we want to prioritize the allocation of the available stock over the set of orders. This prioritization is marked by parameterisable criteria that refer to the type of customer placing the order, as well as to some attribute of the order itself. In this project, a study is carried out on which technique is the most appropriate to solve the problem by the type of orders and the profile of the company's customers, considering algorithms that find an approximate solution and algorithms that find an optimal solution. The chosen technique is the one that is implemented in the company's SAP system. Based on the chosen prioritization criteria, the orders are scored, and the selection of orders to be served that achieve the best score while satisfying the stock constraints is obtained. The solution generates a distribution of the warehouse stocks for each product in the selected orders

Absorption conformations in the intercalation process of polycarboxylate ether based superplasticizers into montmorillonite clay

The intercalation of polycarboxylate based superplasticizers (PCE) into montmorillonite clay (MNT) is arranged preferably by two types of absorption conformations: one-to-one conformation and bridging conformation. A third model named plugged conformation is described but it seems not appropriate to polymers having anionic charge and it would be possible only for very particular cases. The preferred conformation of absorption of the PCE polymer is determined by key properties of the polymer and the clay. For the polymer, the two main characteristics are the length of side chains and the side chain density. For the MNT clay, the mains properties are the layer charge and to a lesser extent the morphology of the clay particle. PCE anionic charge is not a determining factor for the absorption conformation but is a key factor for the earlier saturation of the interlaminar space by intercalation. Since many variables are interplaying simultaneously and complementarily, the interaction process between PCE polymers and MNT clays is very complex that deserves further studies.Peer ReviewedPostprint (author's final draft

L’atenció als malalts d’edat avançada en un hospital d’aguts de l’illa de Mallorca: L’Hospital Universitari Son Dureta

L’envelliment de la població repercuteix directament en la utilització dels recursos sanitaris, tant comunitaris com hospitalaris. Els hospitals d’aguts, com l’Hospital Universitari Son Dureta, varen ser dissenyats per atendre els pacients aguts i joves. L’any 2009 un 57% dels ingressos en aquest hospital, excloent-ne el pavelló maternoinfantil, varen ser de pacients més grans de 65 anys. Un 44% va correspondre a la franja d’edat de 65 a 74 anys, mentre que els més grans de 75 anys varen representar el 56%. El fet d’arribar a edats avançades, gràcies als avenços mèdics, comporta cronicitat, habitualment amb diverses malalties associades (pluripatologia). En el grup de més grans de 65 anys, com a causa d’ingrés, la cardiopatia isquèmica i la bronquitis crònica predominen en l’home, la fractura de maluc en la dona i la insuficiència cardíaca, la causa més important d’ingrés, es reparteix uniformement en ambdós sexes. El sistema sanitari ha d’adaptar-se per respondre a les necessitats actuals dels ciutadans, per canviar l’objectiu del segle XX, «curar», pel del segle XXI, «curar i cuidar». Per a això és necessària la integració real dels serveis sanitaris i socials, com també l’atenció primària i l’especialitzada. El canvi va més enllà de models organitzatius, es tracta d’un canvi cultural que té un impacte important.El envejecimiento de la población está repercutiendo directamente en la utilización de los recursos sanitarios, tanto comunitarios como hospitalarios. Los hospitales de agudos, como el Hospital Universitario Son Dureta, fueron diseñados para atender a pacientes agudos y jóvenes. En el año 2009 un 57% de los ingresos en este hospital, excluyendo el pabellón materno-infantil, fueron pacientes mayores de 65 años. Un 44% correspondió a la franja de edad de 65 a 74 años, en tanto los mayores de 75 años representaron el 56%. El hecho de llegar a edades avanzadas, gracias a los avances médicos, comporta cronicidad, habitualmente con varias enfermedades asociadas (pluripatología). En el grupo de mayores de 65 años, como causa de ingreso, la cardiopatía isquémica y la bronquitis crónica predominan en el varón, la fractura de cadera en la mujer y la insuficiencia cardiaca, la causa más importante de ingreso, se reparte por igual en ambos sexos. El sistema sanitario debe adaptarse para responder a las necesidades actuales de los ciudadanos, para cambiar el objetivo del siglo XX, «curar», al del siglo XXI, «curar y cuidar». Para ello es necesaria la integración real de los servicios sanitarios y sociales así como la atención primaria y la especializada. El cambio va más alla de modelos organizativos, se trata de un cambio cultural de amplio calado

Influence of the polymer structure of polycarboxylate-based superplasticizers on the intercalation behaviour in montmorillonite clays

The influence of polymeric structure of polycarboxylate-ether (PCE) based superplasticizers on the intercalation behavior in sodium montmorillonite clay (Na-MNT) is investigated by performing in-situ X-ray diffraction (XRPD) on fresh, unaltered clay pastes. The use of this technique reveals the real influence of the PCE structure and of the PCE/clay dosage ratio on the expansion profile of the clay. This is not observed with the traditional XRPD methodology performed on dried clay pastes, which shows the same values of d-spacing despite using polymers of diverse structures. It is observed that PCE polymers with long side chains and high side chain density result in larger expansion. Additionally, polymers with a high anionic charge saturate the interlaminar space of montmorillonite at a lower dosage. The experimental results also indicate that clay exfoliation is critical in the intercalation process and the exfoliation tendency of the clay is influenced by the structure of PCE polymers.Peer ReviewedPostprint (author's final draft

Influence of experimental procedure on d-spacing measurement by XRD of montmorillonite clay pastes containing PCE-based superplasticizer

This study investigates the influence of the experimental procedure on determining the d-space enlargement of montmorillonite clay (MNT) produced by the absorption of polycarboxylate (PCE) based superplasticizers. d-Spacing alterations registered by in situ X-ray Diffraction (XRD) analysis on fresh clay pastes have been compared against the results obtained when clay pastes are previously centrifuged and dried (reference methodology reported in bibliography). Data from experiments show relevant differences between the two methodologies. While MNT clay d-spacing present limited expansion when recorded on samples previously separated and dried, direct XRD for fresh clay pastes shows much larger expansion of inter-laminar space. Clay expansion evolves with the increase of PCE dosage up to 3 times larger than typical data recorded when samples previously dried. The results shown here indicates that information collected following the typical experimental procedure based on sample drying could not be representative of MNT clay interference on dispersion mechanism of PCE superplasticizers.Peer ReviewedPostprint (author's final draft

Modelización del mecanismo de pérdida de consistencia provocado por arcillas en pastas de cemento con superplastificantes base policarboxilato

[ES] Este trabajo investiga acerca del mecanismo de interferencia provocado por arcillas sobre la fluidez de sistemas cementosos con condiciones asimilables al HAC en cuanto a baja relación agua/cemento y alta dosis de aditivo basado en polímeros de éter policarboxílico. Se propone una sistemática para determinar cómo repercuten de forma aislada la absorción de agua y la inhibición del efecto dispersante del aditivo, a partir de la cual se describe el mecanismo de sobre-absorción de la arcilla provocado por la intercalación múltiple de cadenas laterales.Borralleras, P.; Segura, I.; Aguado, A. (2018). Modelización del mecanismo de pérdida de consistencia provocado por arcillas en pastas de cemento con superplastificantes base policarboxilato. En HAC 2018. V Congreso Iberoamericano de hormigón autocompactable y hormigones especiales. Editorial Universitat Politècnica de València. 279-289. https://doi.org/10.4995/HAC2018.2018.5634OCS27928

Incomplete SMT techniques for solving non-linear formulas over the integers

We present new methods for solving the Satisfiability Modulo Theories problem over the theory of QuantifierFree Non-linear Integer Arithmetic, SMT(QF-NIA), which consists of deciding the satisfiability of ground formulas with integer polynomial constraints. Following previous work, we propose to solve SMT(QF-NIA) instances by reducing them to linear arithmetic: non-linear monomials are linearized by abstracting them with fresh variables and by performing case splitting on integer variables with finite domain. For variables that do not have a finite domain, we can artificially introduce one by imposing a lower and an upper bound and iteratively enlarge it until a solution is found (or the procedure times out). The key for the success of the approach is to determine, at each iteration, which domains have to be enlarged. Previously, unsatisfiable cores were used to identify the domains to be changed, but no clue was obtained as to how large the new domains should be. Here, we explain two novel ways to guide this process by analyzing solutions to optimization problems: (i) to minimize the number of violated artificial domain bounds, solved via a Max-SMT solver, and (ii) to minimize the distance with respect to the artificial domains, solved via an Optimization Modulo Theories (OMT) solver. Using this SMT-based optimization technology allows smoothly extending the method to also solve Max-SMT problems over non-linear integer arithmetic. Finally, we leverage the resulting Max-SMT(QF-NIA) techniques to solve ∃∀ formulas in a fragment of quantified non-linear arithmetic that appears commonly in verification and synthesis applications.Peer ReviewedPostprint (author's final draft