Survey on Combinatorial Register Allocation and Instruction Scheduling

Register allocation (mapping variables to processor registers or memory) and instruction scheduling (reordering instructions to increase instruction-level parallelism) are essential tasks for generating efficient assembly code in a compiler. In the last three decades, combinatorial optimization has emerged as an alternative to traditional, heuristic algorithms for these two tasks. Combinatorial optimization approaches can deliver optimal solutions according to a model, can precisely capture trade-offs between conflicting decisions, and are more flexible at the expense of increased compilation time. This paper provides an exhaustive literature review and a classification of combinatorial optimization approaches to register allocation and instruction scheduling, with a focus on the techniques that are most applied in this context: integer programming, constraint programming, partitioned Boolean quadratic programming, and enumeration. Researchers in compilers and combinatorial optimization can benefit from identifying developments, trends, and challenges in the area; compiler practitioners may discern opportunities and grasp the potential benefit of applying combinatorial optimization

Guía para la elaboración de un Plan de Implantación de un Sistema APPCC en el área de restauración de un centro médico

La seguridad alimentaria presenta uno de los objetivos a abordar de manera prioritaria tanto en industria alimentaria como en restauración en cualquiera de sus ámbitos. A raíz de esta creciente preocupación del consumidor, el ámbito legal dentro de la Unión Europea, obliga a los operadores de las empresas del sector a desarrollar programas y procedimientos que aseguren la inocuidad de sus productos y elaboraciones, basadas en los principios del Análisis de Peligros y Puntos de Control Críticos (APPCC). Este sistema se fundamenta científicamente y tiene carácter sistemático, y el presente trabajo formula los pasos a seguir para evaluar los peligros específicos y establecer medidas de control basadas en la prevención, eliminación y/o reducción de éstos a niveles aceptables en cada una de las fases específicas del proceso, en lugar de realizar este análisis en las elaboraciones finales, lo que supone una ventaja para la empresa a múltiples niveles. Además, el trabajo también explica cómo desarrollar los requisitos previos que deben adoptarse conforme a los principios de higiene alimentaria según dicta el Codex Alimentarius. La presente guía se presenta para abordar de una forma simple y eficaz la implantación de un Sistema APPCC dentro del área de restauración de un centro hospitalario, ofreciendo una metodología eficaz para la verificación y validez de los Puntos de Control Críticos con el fin de garantizar el cumplimiento y control efectivo del sistema de APPCC

Influence of drug treatment with antidepressants and antipsychotics on plasma urea levels

Roberto Lozano OrtizPharmacy Department, Hospital Real Nuestra Señora de Gracia, Zaragoza, SpainHaving read with great interest the article by Goto et al1 and in order to clarify further some of the results presented in this article, especially with regard to the action of atypical antipsychotic drugs on glutamate and the glutamine to creatine ratio, it would seem appropriate to reiterate the comments made by Lozano et al in a presentation at the 55th National Congress of the Spanish Association of Hospital Pharmacists in 2010, where we proposed the likely oxide, glutamine, and glutamate levels in the brain, as a result of the reaction of nitric oxide with glutamine to yield glutamate and nitrogen gas. A summary of this research is provided as follows.View original paper by Goto and colleagues

Constraint programming for random testing of a trading system

Financial markets use complex computer trading systems whose failures can cause serious economic damage, making reliability a major concern. Automated random testing has been shown to be useful in nding defects in these systems, but its inherent test oracle problem (automatic generation of the expected system output) is a drawback that has typically prevented its application on a larger scale. Two main tasks have been carried out in this thesis as a solution to the test oracle problem. First, an independent model of a real trading system based on constraint programming, a method for solving combinatorial problems, has been created. Then, the model has been integrated as a true test oracle in automated random tests. The test oracle maintains the expected state of an order book throughout a sequence of random trade order actions, and provides the expected output of every auction triggered in the order book by generating a corresponding constraint program that is solved with the aid of a constraint programming system. Constraint programming has allowed the development of an inexpensive, yet reliable test oracle. In 500 random test cases, the test oracle has detected two system failures. These failures correspond to defects that had been present for several years without being discovered neither by less complete oracles nor by the application of more systematic testing approaches. The main contributions of this thesis are: (1) empirical evidence of both the suitability of applying constraint programming to solve the test oracle problem and the e ectiveness of true test oracles in random testing, and (2) a rst attempt, as far as the author is aware, to model a non-theoretical continuous double auction using constraint programming.Castañeda Lozano, R. (2010). Constraint programming for random testing of a trading system. http://hdl.handle.net/10251/8928.Archivo delegad

Integration of Activities in the natural environment as contents of education trhough collaborative action-research

The different values †given to Activities in the Natural Environment have become a mandated content block within the area of Physical Education. This research is based on the urging of its practical development of a school in the city of Zaragoza. So far, the analysis of these practices in this school, refers to some specific experiences focused on the volunteer activities done during the «snow week», which means less participant students. Collaborative action-research is the methodology used for this purpose, therefore team-work is demanded to overcome the limitations presented by this block of contents: teacher training as well as both facilities and materials must be provided. Thus, we found two groups of conclusions: firstly, the factors necessary to establish a dynamic collaborative work among teachers of this school. Secondly, the aspects required to design and strengthen the proposed contents of environmental Activities in the school, adapting them to its own physical contextual characteristic

Have real interest rates really fallen that much in Spain?

This paper analyses the behaviour of real interest rates in the Spanish economy over the last 15 years. Since inflation-indexed-bonds are not available, changes in implicit real interest rates are estimated using several approaches suggested by macroeconomic and financial theory. In particular, we employ equilibrium conditions of a representative agent under several specifications of preferences. Moreover, we exploit no-arbitrage conditions in securities markets. The evidence we report indicates that inflation uncertainty could account for a notable part of the observed decrease in nominal rates. Consequently, the actual real cost of financing might have decreased significantly less than what the course of ex-post real rates would sugges

Confronting dark matter with the diphoton excess from a parent resonance decay

A diphoton excess with an invariant mass of about 750 GeV has been recently reported by both ATLAS and CMS experiments at LHC. While the simplest interpretation requires the resonant production of a 750 GeV (pseudo)scalar, here we consider an alternative setup, with an additional heavy parent particle which decays into a pair of 750 GeV resonances. This configuration improves the agreement between the 8 TeV and 13 TeV data. Moreover, we include a dark matter candidate in the form of a Majorana fermion which interacts through the 750 GeV portal. The invisible decays of the light resonance help to suppress additional decay channels into Standard Model particles in association with the diphoton signal. We realise our hierarchical framework in the context of an effective theory, and we analyse the diphoton signal as well as the consistency with other LHC searches. We finally address the interplay of the LHC results with the dark matter phenomenology, namely the compatibility with the relic density abundance and the indirect detection bounds.Comment: 11 figures, 2 tables, 29 page