Efficiency & sustainability model to design and manage two-stage logistic networks

The distribution and storage efficiency together with the environmental sustainability are mandatory targets to consider when designing and managing modern supply chain (SC) networks. The current literature continuously looks for quantitative multi-perspective strategies and models, including and best balancing such issues that often diverge. This paper presents and applies a bi-objective optimization model to best design and manage two-stage logistic networks looking for the best trade-off between the SC stock level and the building and distribution environmental impact. The existence of good balance confirms the possibility to reduce the average SC stock level without a relevant increase of the emissions due to frequent replenishments

Sacrifices for Development or Thirst for Capital Accumulation? Case Study on the “El Diquís Hydroelectric Dam” in Costa Rica.

Costa Rica’s state-led model of energy generation based on large-scale investments in hydropower has given the country autonomy in generating its own energy as well as sovereignty over its natural resources. Successive governments have used nationalist and ecological discourses to support the continued expansion of hydropower as the path to economic development. In more recent decades however, a number of factors have been eroding the dominance of the state-led hydropower development model. Some of those elements are the national and international pressures to liberalize and privatize the energy sector, an increasing body of scientific evidence indicating that large-scale hydropower in the tropics may in fact be detrimental to the environment, and an increasing pressure for the energy sector to shift away from large-scale hydropower, in favor of small-scale hydropower and other renewable energy sources. This research uses El Diquís Hydroelectric Project (EDHP) as case study. This hydroelectric dam is a critical project linked to future energy generation for export and reflects the evolving and highly contested dynamics of hydropower politics in Costa Rica today. It may well serve as a turning point in national energy policy, the future of large-scale infrastructure and hydropower projects, and indigenous rights. This paper shows how EDHP did not serve the national interest based on a complex web of forces and interests at play

Automated Computation of Leaf Area index from Fruit Trees using Improved Image Processing Algorithms Applied to canopy cover digital photograpies

Leaf Area index (LAI) is a critical parameter in plant physiology for models related to growth, photosynthetic activity and evapotranspiration. It is also important for farm management purposes, since it can be used to assess the vigor of trees within a season with implications in water and fertilizer management. Among the diverse methodologies to estimate LAI, those based on cover photography are of great interest, since they are non-destructive, easy to implement, cost effective and have been demonstrated to be accurate for a range of tree species. However, these methods could have an important source of error in the LAI estimation due to the inclusion within the analysis of non-leaf material, such as trunks, shoots and fruits depending on the complexity of canopy architectures. This paper proposes a modified cover photography method based on specific image segmentation algorithms to exclude contributions from nonleaf materials in the analysis. Results from the implementation of this new image analysis method for cherry tree canopies showed a significant improvement in the estimation of LAI compared to ground truth data using allometric methods and previously available cover photography methods. The proposed methodological improvement is very simple to implement, with numerical relevance in species with complex 3D canopies where the woody elements greatly influence the total leaf area.Sociedad Argentina de Informática e Investigación Operativ

Automated Computation of Leaf Area index from Fruit Trees using Improved Image Processing Algorithms Applied to canopy cover digital photograpies

Leaf Area index (LAI) is a critical parameter in plant physiology for models related to growth, photosynthetic activity and evapotranspiration. It is also important for farm management purposes, since it can be used to assess the vigor of trees within a season with implications in water and fertilizer management. Among the diverse methodologies to estimate LAI, those based on cover photography are of great interest, since they are non-destructive, easy to implement, cost effective and have been demonstrated to be accurate for a range of tree species. However, these methods could have an important source of error in the LAI estimation due to the inclusion within the analysis of non-leaf material, such as trunks, shoots and fruits depending on the complexity of canopy architectures. This paper proposes a modified cover photography method based on specific image segmentation algorithms to exclude contributions from nonleaf materials in the analysis. Results from the implementation of this new image analysis method for cherry tree canopies showed a significant improvement in the estimation of LAI compared to ground truth data using allometric methods and previously available cover photography methods. The proposed methodological improvement is very simple to implement, with numerical relevance in species with complex 3D canopies where the woody elements greatly influence the total leaf area.Sociedad Argentina de Informática e Investigación Operativ

Using the Web as Input and Discourse Interactions for the Construction of Meaning and the Acquisition of Lexical Units in University Level English as a Foreign Language

The purpose of this mixed-methods study was to examine the impact of Web multimodality plus dialogical interactions in the acquisition and retention of novel lexical items among EFL students under a social constructionist framework. The lexical acquisition of 107 1st-year English majors at the University of Costa Rica was analyzed through Simultaneous Multiple Linear Regression and discourse analysis. Treatment A group, exposed to multiple Web input sources and allowed to discuss their findings dialogically, was compared to an only-Web group and a Control group. The difference in means between pre and posttests indicates that scores increased after each treatment. The Control group showed a decrease between pre and posttest mean scores. The results of the regression were statistically significant and the marginal mean of the Web plus dialogue group was statistically different from the means of the Web-only and Control groups (p < .05). Other variables such as learning preference, language use and background did not have any predictive power in the model. The qualitative section showed that students positively appraised the use of Dictionary.com and Google Translate in the search for meaning. This finding reinforces the validity of using the Web to present novel vocabulary to EFL students. The examination of 64 learners' oral interactions demonstrated that the majority of their interventions indicated co-construction of knowledge supporting Gunawardena et al.'s model (1997, 1998) and the use of Repetition, Code mixing, and Social content strategies. The progression of learners' interactions along the different phases of the co-construction model provided evidence of meaning creation and accounted for the development of a semantic framework for the comprehension of the target vocabulary through the collaboration of the different participants. The results of this study have pedagogical implications by informing practitioners about student preferences when integrating multimodalities into FL instruction and the intrinsic value of dialogical interactions in the social construction of meaning

Neutrino Masses in Split Supersymmetry

We investigate the possibility to generate neutrino masses in the context of Split supersymmetric scenarios where all sfermions are very heavy. All relevant contributions coming from the R-parity violating terms to the neutrino mass matrix up to one-loop level are computed, showing the importance of the Higgs one-loop corrections. We conclude that it is not possible to generate all neutrino masses and mixings in Split SUSY with bilinear R-Parity violating interactions. In the case of Partial Split SUSY the one-loop Higgs contributions are enough to generate the neutrino masses and mixings in agreement with the experiment. In the context of minimal SUSY SU(5) we find new contributions which help us to generate neutrino masses in the case of Split SUSY.Comment: 33 pages, 6 figures, to appear in Physical Review

Automatización para Control, Monitoreo de Interruptores y transformador en Subestación Eléctrica Reductora de San Blas.

Proyecto de Graduación (Bachillerato en Ingeniería Electrónica). Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Electrónica, 2002.Este proyecto trata acerca de la automatización de la Subestación Eléctrica Reductora de San Blas, localizada en Cartago, Costa Rica. Mediante esta subestación se controla el flujo eléctrico que abastece las zonas de San Rafael, Los Ángeles y Cartago. La automatización consistió en el control remoto de las funciones de cierre y apertura de los cuatro reconectadores dentro de la subestación a través del sistema SCADA de JASEC. Además se logró adquirir e integrar en el mismo sistema la información referente a niveles de voltaje y corriente, junto con otras variables de gran importancia para determinar la calidad del servicio brindado. En el diseño y la implementación se utilizó un controlador lógico programable (PLC), el cual fue colocado dentro de un gabinete de control ubicado en la caseta de la subestación, el cual establece comunicaciones mediante protocolo Modbus mediante puerto tipo Ethernet en TCP/IP. Cuatro medidores de variables, cada uno fue colocado en cada reconectador, formando una red RS-485, la cual posteriormente es transformada en el gabinete de control a red tipo Ethernet. Para las comunicaciones se incluyó en el gabinete de control un MODEM con capacidades de conexión a largas distancias, además de un “switch” para redes Ethernet. En el mismo gabinete de control se incluyó una fuente de alimentación ininterrumpible que abastece de energía a todos los equipos de comunicación y de control.Junta Administrativa del Servicio Eléctrico de Cartago JASE

Class of PPT bound entangled states associated to almost any set of pure entangled states

We analyze a class of entangled states for bipartite $d \otimes d$ systems, with $d$ non-prime. The entanglement of such states is revealed by the construction of canonically associated entanglement witnesses. The structure of the states is very simple and similar to the one of isotropic states: they are a mixture of a separable and a pure entangled state whose supports are orthogonal. Despite such simple structure, in an opportune interval of the mixing parameter their entanglement is not revealed by partial transposition nor by the realignment criterion, i.e. by any permutational criterion in the bipartite setting. In the range in which the states are Positive under Partial Transposition (PPT), they are not distillable; on the other hand, the states in the considered class are provably distillable as soon as they are Nonpositive under Partial Transposition (NPT). The states are associated to any set of more than two pure states. The analysis is extended to the multipartite setting. By an opportune selection of the set of multipartite pure states, it is possible to construct mixed states which are PPT with respect to any choice of bipartite cuts and nevertheless exhibit genuine multipartite entanglement. Finally, we show that every $k$-positive but not completely positive map is associated to a family of nondecomposable maps.Comment: 12 pages, 3 figures. To appear in Phys. Rev.

Fruit Maturity Estimation based on Color Scales

Color is an important parameter used to estimate fruit maturity and optimal harvest time. In this paper a general methodology for estimating fruit maturity based on the development of a color scale is proposed. Maturity estimation is performed by computing of the fruit representative color and its comparison with the colors of the scale. In experimentation the case of grape maturity estimation based on seed color is presented. The method is simple and eff ective, allowing its application in the real processes.Eje: XII Workshop de Computación gráfica, Imágenes y VisualizaciónRed de Universidades con Carreras de Informática (RedUNCI

Experiencia de pasantía en el PhET, Universidad de Colorado en Boulder

Este trabajo presenta los resultados de la pasantía realizada en el PhET de la Universidad de Colorado en Boulder y la sistematización de la experiencia basada en la observación, evaluación, comprensión y reflexión del proceso. Los principales resultados obtenidos de esta experiencia se pueden percibir principalmente en el PEM, donde el equipo de trabajo se ha fortalecido y cuenta con más desarrolladores, esto ayudó a que los productores académicos se pudieran dedicar específicamente al diseño instruccional y la mediación pedagógica, así como a producir materiales multimedia más complejos. Se implementó una metodología de desarrollo ágil Ad hoc para el PEM, que ha contribuido a la finalización de programas informáticos educativos en tres meses. A futuro, se espera incluir a estudiantes en los procesos de validación de los laboratorios virtuales en cuanto a usabilidad, accesibilidad y experiencia del usuario, así como su funcionalidad en la educación a distancia. Esto enriquecerá el proceso de desarrollo y la utilidad del material didáctico