Model-based run-to-run optimization under uncertainty of biodiesel production

A significant source of uncertainty in biodiesel production is the variability of feed composition since the percentage and type of triglycerides varies considerably across different raw materials. Also, due to the complexity of both transesterification and saponification kinetics, first-principles models of biodiesel production typically have built-in errors (structural and parametric uncertainty) which give rise to the need for obtaining relevant data through experimental design in modeling for optimization. A run-to-run optimization strategy which integrates tendency models with Bayesian active learning is proposed. Parameter distributions in a probabilistic model of process performance are re-estimated using data from experiments designed for maximizing information and performance. Results obtained highlight that Bayesian optimal design of experiments using a probabilistic tendency model is effective in achieving the maximum ester content and yield in biodiesel production even though significant uncertainty in feed composition and modeling errors are present.Fil: Luna, Martín Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Reg.santa Fe. Instituto de Desarrollo y Diseño; ArgentinaFil: Martinez, Ernesto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Regional Santa Fe. Instituto de Desarrollo y Diseño; Argentin

Náyades (Bivalvia - Hyriidae) en el “Conglomerado osífero” (Mioceno tardío), Entre Ríos, Argentina

The freshwater mussels of the family Hyriidae (Bivalvia) are widespread in the Neotropical region, including several fossil and living species of the genus Diplodon Spix. A specimen assigned to Diplodon sp., recovered from the "Conglomerado osífero" (late Miocene) at La Toma Vieja, north of Paraná City (Entre Ríos Province, Argentina), is described herein. The report of Diplodon sp. in the "Conglomerado osífero" would support the traditional interpretation of a fluvial paleoenvironment for this horizon. This is the first accurate fossil record of the genus for the Entre Ríos Province, extending the occurrence of the family Hyriidae to the late Miocene of the Mesopotamian region.Los mejillones de agua dulce de la familia Hyriidae (Bivalvia) están muy extendidos en la región Neotropical; incluido el género Diplodon con varias especies fósiles y actuales. Se describe aquí un espécimen asignado a Diplodon sp. recuperado del “Conglomerado osífero” (Mioceno tardío) en La Toma Vieja, al norte de la ciudad de Paraná (provincia de Entre Ríos, Argentina). El reporte de Diplodon sp. en el “Conglomerado osífero” apoyaría la interpretación tradicional de un paleoambiente fluvial para este nivel. Además, representa el primer registro fósil exacto del género para la provincia de Entre Ríos, extendiendo la presencia de la familia Hyriidae hasta el Mioceno tardío de la región mesopotámica.Fil: Pérez, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; ArgentinaFil: Brandoni, Diego. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Martinez, Sergio. Universidad de la Republica; Urugua

An evolutionary algorithm for the surface structure problem

Many macroscopic properties: hardness, corrosion, catalytic activity, etc. are directly related to the surface structure, that is, to the position and chemical identity of the outermost atoms of the material. Current experimental techniques for its determination produce a “signature” from which the structure must be inferred by solving an inverse problem: a solution is proposed, its corresponding signature computed and then compared to the experiment. This is a challenging optimization problem where the search space and the number of local minima grows exponentially with the number of atoms, hence its solution cannot be achieved for arbitrarily large structures. Nowadays, it is solved by using a mixture of human knowledge and local search techniques: an expert proposes a solution that is refined using a local minimizer. If the outcome does not fit the experiment, a new solution must be proposed again. Solving a small surface can take from days to weeks of this trial and error method. Here we describe our ongoing work in its solution. We use an hybrid algorithm that mixes evolutionary techniques with trusted region methods and reuses knowledge gained during the execution to avoid repeated search of structures. Its parallelization produces good results even when not requiring the gathering of the full population, hence it can be used in loosely coupled environments such as grids. With this algorithm, the solution of test cases that previously took weeks of expert time can be automatically solved in a day or two of uniprocessor time

Effects of Implicit and Explicit Teacher Written Corrective Feedback on Adult Learners’ Written Grammatical Accuracy

El propósito de este proyecto experimental es investigar diferentes formas de corrección docente en la escritura para encontrar la forma más efectiva en la adquisición de adverbios de modo. Los investigadores miden la adquisición de este dispositivo gramatical como una estrategia para a guiar a los aprendices hacia una práctica de producción escrita más efectiva. Esta investigación se centra en dos grupos experimentales y un grupo de control del centro de lenguas de una universidad. Cada uno de los grupos cuenta con diez aprendices de nivel intermedio (B2), de acuerdo al Marco Común Europeo de Referencia para las Lenguas (MCERL). Para lograr su propósito, los investigadores implementan diferentes estrategias de realimentación correctiva como; corrección implícita y explícita en la escritura en cada uno de los grupos. Paralelamente, el diseño de investigación usa un enfoque mixto el cual incluye tres tareas escritas, dos cuestionarios abiertos y observaciones por parte del profesor de los grupos. Los resultados indican que la realimentación explicita en la escritura es más efectiva en el incremento de la adquisición de adverbios de modo en aprendices adultos (B2), comparado con los efectos de la corrección escrita implícita docente o ninguna realimentación correctiva en un periodo de corto plazo. Por consiguiente, estos resultados sugieren que la realimentación correctiva explicita es más útil en ayudar a los aprendices (B2) en el uso de los adverbios de modo. De esta forma, los aprendices pueden expresarse más descriptivamente en su producción escrita. Los resultados también sugieren que la realimentación implícita puede motivar y fomentar el aprendizaje autónomo y colaborativo en aprendices adultos (B2). Los resultados revelan que los aprendices tienen una perspectiva positiva con respecto a sus correcciones escritas realimentarías docentes explicitas e implícitas y consideran las correcciones convenientes para su aprendizaje de una segunda lengua con respecto al desarrollo de habilidades comunicativas en la escritura. Sugerencias para futuras investigaciones incluyen la investigación con grupos más grandes, más tiempo para la recolección de información y más dispositivos gramaticales con diferentes perfiles y niveles de competencia

Criptografía Cuántica en Redes Clásicas

Quantum Key Distribution (QKD) is the first technology derived from Quantum Information and Quantum Computation that is being marketed. To date, the commercial applications are in the encryption of point to point links. Now, the next logical step is about to be taken. Full quantum networks able to transport the keys to be used in symmetric key cryptography with a security level previously unattained are being designed. The proof of concept of many of the ingredients needed exist and networks with a few nodes have been implemented. The first networks will cover a metropolitan area and demonstrate the feasibility of large-scale QKD integrated with classical networks. If it succeeds in the marketplace, this could signal a major shift in how cryptography is used today

Characterization of abiotic coaditions affecting vegetation distribution in the river plate coastal plain, Argentina

The river Plate coastal plain is located in northeastern Buenos Aires province, where geological events such as sea transgressions and regressions in the Holocene have produced a stratigraphic column with marine-estuarine, fluviatile and continental sediments, as well as a variety of landforms and soils. The aim of this paper is to describe these different coastal settings and their influence in the distribution of plant communities

Fuel: A Fast General Purpose Object Graph Serializer

International audienceSince objects need to be stored and reloaded on different environments, serializing object graphs is a very important activity. There is a plethora of serialization frameworks with different requirements and design trade-offs. Most of them are based on recursive parsing of the object graphs, an approach which often is too slow. In addition, most of them prioritize a language-agnostic format instead of speed and language-specific object serialization. For the same reason, such serializers usually do not support features like class-shape changes, global references or executing pre and post load actions. Looking for speed, some frameworks are partially implemented at Virtual Machine (VM) level, hampering code portability and making them difficult to understand, maintain and extend. In this paper we present Fuel, a general-purpose object serializer based on these principles: (1) speed, through a compact binary format and a pickling algorithm which invests time in serialization for obtaining the best performance on materialization; (2) good object-oriented design, without special help at VM; (3) serialize any object, thus have a full-featured language-specific format. We implement and validate this approach in Pharo, where we demonstrate that Fuel is faster than other serializers, even those with special VM support. The extensibility of Fuel made possible to successfully serialize various objects: classes in Newspeak, debugger stacks, and full CMS object graphs

Information Rrconciliation for quantum key distribution

Quantum key distribution (QKD) relies on quantum and classical procedures in order to achieve the growing of a secret random string -the key- known only to the two parties executing the protocol. Limited intrinsic efficiency of the protocol, imperfect devices and eavesdropping produce errors and information leakage from which the set of measured signals -the raw key- must be stripped in order to distill a final, information theoretically secure, key. The key distillation process is a classical one in which basis reconciliation, error correction and privacy amplification protocols are applied to the raw key. This cleaning process is known as information reconciliation and must be done in a fast and efficient way to avoid cramping the performance of the QKD system. Brassard and Salvail proposed a very simple and elegant protocol to reconcile keys in the secretkey agreement context, known as Cascade, that has become the de-facto standard for all QKD practical implementations. However, it is highly interactive, requiring many communications between the legitimate parties and its efficiency is not optimal, imposing an early limit to the maximum tolerable error rate. In this paper we describe a low-density parity-check reconciliation protocol that improves significantly on these problems. The protocol exhibits better efficiency and limits the number of uses of the communications channel. It is also able to adapt to different error rates while remaining efficient, thus reaching longer distances or higher secure key rate for a given QKD system

Quantum key distribution based on selective post-processing in passive optical networks

One of the main obstacles to the widespread adoption of quantum cryptography has been the difficulty of integration into standard optical networks, largely due to the tremendous difference in power of classical signals compared with the single quantum used for quantum key distribution. This makes the technology expensive and hard to deploy. In this letter, we show an easy and straightforward integration method of quantum cryptography into optical access networks. In particular, we analyze how a quantum key distribution system can be seamlessly integrated in a standard access network based on the passive optical and time division multiplexing paradigms. The novelty of this proposal is based on the selective post-processing that allows for the distillation of secret keys avoiding the noise produced by other network users. Importantly, the proposal does not require the modification of the quantum or classical hardware specifications neither the use of any synchronization mechanism between the network and quantum cryptography devices