Understanding the impact of introducing Lambda expressions in Java Programs

Background: The Java programming language version eight introduced several features that encourage the func­ tional style of programming, including the support for lambda expressions and the Stream API. Currently, there is a common wisdom that refactoring legacy code to introduce lambda expressions, besides other potential benefits, simplifies the code and improves program comprehension. Aims: The purpose of this work is to investigate this belief, conducting an in­depth study to evaluate the effect of introducing lambda expressions on program compre­hension. Method: We conducted this research using a mixed­method approach. For the quantitative method, we quantitatively analyzed 158 pairs of code snippets extracted directly either from GitHub or from recommendations from three tools (RJTL, NetBeans, and IntelliJ). We also surveyed practitioners to collect their perceptions about the benefits on program comprehension when introducing lambda expressions. We asked practitioners to evaluate and rate sets of pairs of code snippets. Results: We found contradictory results in our research. Based on the quantitative assessment, we could not find evidence that the introduction of lambda expressions improves software readability— one of the components of program comprehension. Our results suggest that the transformations recommended by the aforementioned tools decrease program comprehension when assessed by two state­of­the­art models to esti­mate readability. Differently, our findings of the qualitative assessment suggest that the introduction of lambda expression improves program comprehension in three scenarios when: we convert anonymous inner classes to a lambda expression, use structural loops with inner conditional to an anyMatch operator, and apply structural loops to filter operator combined with a collect method. Implications: We argue in this paper that one can improve program comprehension when he/she applies particular transformations to introduce lambda expressions (e.g., re­placing anonymous inner classes with lambda expressions). Also, the opinion of the participants highlights which kind of transformation for introducing lambda might be advantageous. This might support the implementation of effective tools for automatic program transformations

Experiences of Community Wind Electrification Projects in Bolivia: Evaluation and Improvements for Future Projects

Postprint (published version

Strategic configurations and performance: a study in micro and small business retailers

Um conjunto expressivo de estudos advogam a interdependência e complementariedade entre variáveis ambientais, estruturais, estratégicas e pessoais do estrategista na formação da estratégia. São raros os levantamentos que associam essas variáveis com desempenho de empresas de pequeno porte. Conjugando variáveis nessas dimensões, a pesquisa aqui apresentada objetivou verificar quais configurações estratégicas compostas pelo processo de desenvolvimento da estratégia, conteúdo da estratégia, atitude empreendedora, modo administrativo e incerteza ambiental percebida associaram-se ao desempenho de empresas de pequeno porte do varejo de vestuário. Dados levantados em survey com 228 empresas e investigados pela técnica de análise de clusters, revelaram dois grupos/clusters de empresas com configurações e níveis de desempenho distintos. Os resultados indicam a relação de interdependência de variáveis na explanação da heterogeneidade do desempenho organizacional.A significant number of studies advocate the interdependence and complementarity between environmental, structural, strategic and personal variables in strategy formation. There are rare surveys that link these variables with small businesses performance. Combining several dimensions of these variables, this study aimed to verify which strategy configurations composed by the strategy development process, strategy content, entrepreneurial attitude, administrative mode and perceived environmental uncertainty were associated with the performance of small-sized clothing retail businesses. Data collected by survey with 228 companies and investigated by cluster analysis technique revealed two groups/clusters of companies with different configurations and performance levels. The results indicate the relationship of interdependence among variables in explaining the heterogeneity of organizational performance

O final dos reinos: Diálogos entre Tiwanaku e La Aguada

Este escrito pone de nuevo a dialogar las iconografías de Tiwanaku (altiplano del Titicaca, Bolivia) y La Aguada (Noroeste de la Argentina), a más de 40 años de los trabajos de Rex González y de Ponce Sanginés. Lo hace en un contexto enteramente diferente con un énfasis decolonial. Objetos, imágenes, información etnográfica y arqueólogos de ambos lados de una frontera entre "naciones", se ensamblan con la clara intención de cuestionar supuestos subyacentes muy profundos de la arqueología. Metodología: a partir de los caminos que plantean las imágenes y colores, se amarran en estos nudos también los humanos y las cosas, las experiencias chamánicas y los fenómenos meteorológicos, todos enlazados de modo relacional. Conclusiones: tras poner a dialogar a La Aguada y Tiwanaku, con base en nuestras trayectorias investigativas, la discusión desemboca en una reflexión acerca de las consecuencias presentes de naturalizar miradas segmentadas y funcionalistas de los mundos animales y vegetales en el pasado, que se originan en los subyacentes ontológicos de nuestra propia modernidad. Originalidad: el texto apunta a abordar la crítica decolonial a partir del estudio de casos concretos y a aportar a esos debates desde materialidades arqueológicas.This paper once again brings the iconographies of Tiwanaku (Titicaca high plateau, Bolivia) and La Aguada (Northwest of Argentina) into discussion, more than 40 years after the works of Rex González and Ponce Sanginés. It does so in an entirely different context with a decolonial emphasis. Objects, images, ethnographic information and archaeologists from both sides of a border between “nations” are assembled with the clear intention of questioning very deep underlying assumptions of archaeology. Methodology: Beginning with the paths posed by images and colors, these knots also bind humans and things, shamanic experiences and meteorological phenomena. Conclusions: After bringing La Aguada and Tiwanaku into dialogue, based on our research trajectories, the discussion leads to a reflection on the present consequences of naturalizing segmented and functionalist gazes of the animal and plant worlds in the past, which originate in the ontological underpinnings of our own modernity. Originality: The text aims to approach decolonial criticism from the study of concrete cases and to contribute to these debates on the basis of archaeological materiality.Fil: Marconetto, María Bernarda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; ArgentinaFil: Villanueva Criales, Juan Eduardo. Museo Nacional de Etnografía y Folklore; Bolivi

Inkas, “flecheros” y mitmaqkuna : Cambio social y paisajes culturales en los Valles y en los Yungas de Inkachaca/Paracti y Tablas Monte (Cochabamba-Bolivia, siglos XV-XVI)

The research work addresses the changes that occurred in the valley and the Yungas of Cochabamba during the Inka Horizon (1400-1538 AC) while introducing in an exploratory way, the Late Intermediate (1100-1400 AC) and the Middle Horizon (400-1100 AC) periods. In theoretical terms, we emphasize the local human agency (individual and social) as important elements in order to understand the processes of social change. We assume that the complex relational webs generated by the Inka presence in the valleys and the Yungas appear as "traces" in the space (as constructed landscapes: social, agro-hydrological, sacral, administrative, war landscapes etc.) that can be seized from two sources, archaeological and historical, that are seen as complementing each other. We carried out two case studies in the Yungas of Tablas Monte and Inkachaca /Paracti. In both areas, previously unknown to Bolivian archaeology, we examined the impact of the Inka. Based upon material evidence, such as the sophisticated agro-hydrological system sustained by an intensive use of the stone as well as documentary data, we discuss the presence of warrior groups, i.e. that the arrival of the Inka had a relative impact in this area

Techno-economic optimization of isolate micro-grids including PV and Li-Ion Batteries in the Bolivian context

peer reviewedIn Bolivia 44 % of the people living in rural areas do not have reliable access to electric energy. This is due to a combination of unfavourable geography and the lack of economic resources to achieve the necessary infrastructure. In this context, the main goal of this study is to evaluate the economic and technical feasibility of micro-grids including photovoltaic panels (PV), batteries systems and the possible inclusion of diesel generators for off-grid applications. To that aim, a linear optimization model was developed within the Pyomo framework in order to optimize both the installed capacities and dispatch of the PV, battery and diesel sub-systems. The defined objective function is the net present cost. The exogenous inputs of the optimization are the typical demand and solar irradiation of a region of Bolivia in order to achieve results close to real Bolivian systems. Results indicate that due to the high levels of subvention to hydrocarbons, the PV and Li-Ion technology are not yet competitive with a diesel generator for the electrification of rural areas. On the other hand a sensitivity analysis is performed and proves that if the government decide to stop part of the subvention or shared it between conventional and non-conventional sources, the PV becomes competitive and the Li-Ion batteries enter the market around 2020

Impact of Diesel generator limitations in the robust sizing of isolated hybrid Microgrids including PV and batteries

peer reviewedThe recent developments in PV and Lion-ion batteries along with the maturity of gensets technology to provide energy to isolated systems has fostered the use of hybrid micro-grids for rural electrification. In this context, the optimal coupling of different technologies and the minimization of the cost to the final consumer are the objects of a number of previous researches. However, the approach usually relies on deterministic linear programming optimizations (LP), which do not allow to model certain non-linearities and limitations of the components. This paper aims at filling this gap by proposing an optimization of such system, with a detailed representation of each component. The case study of an isolated village (Las Misiones, Bolivia) with a peak electricity consumption of 9.2 MW is analyzed. The considered system comprises a diesel generator; a PV array and Li-Ion batteries whose nominal capacities should be optimized. A robust optimization tool is first proposed with an LP formulation and the net present cost as objective function. The basic model is then modified to take into account more complex operating characteristics of a gen-set operating in part-load. To that aim, the LP problem is changed into a mixed integer linear programing formulation. Results indicate that the more detailed constraints influence the final design of the system and negatively impact the total cost

Techno-economic evaluation of rural electrification in Bolivia: lessons learned from the “El Espino” micro-grid

© 2018 University of Minho. All rights reserved. In the last ten years, Bolivia has gone through a period of economic growth and political stability without precedent in its 200 hundreds years of history. The national government has the ambition to reach a 100 % of rural electrification coverage by 2025. One of the key components for this purpose is the construction and operation of isolated hybrid micro-grids. In order to test this technology a pilot plant was built in September 2015 in the rural village of ‘El Espino’.The objective of this study is the evaluation of the current operation strategy of this micro-grid and the implementation of the project. To that end, monitoring data is used, covering the period 1 of January of 2016 to 31 of july of 2017.The data analysis shows that the average PV efficiency is 9.34 %, the efficiency of the diesel generator is 31.4 % and the round trip efficiency of the battery is 74%. Using the data collected and the techno-economic information of the place, the operation cost of the system for the analyzed period is computed. Finally, an optimal dispatch model based in a mixed-integer linear programming (MILP) is used to find the optimal energy flows in the system that minimize the diesel consumption.status: publishe

Techno-economic evaluation of rural electrification in Bolivia: lessons learned from the “El Espino” micro-grid

peer reviewedIn the last ten years, Bolivia has gone through a period of economic growth and political stability without precedent in its 200 hundreds years of history. The national government has the ambition to reach a 100 % of rural electrification coverage by 2025. One of the key components for this purpose is the construction and operation of isolated hybrid micro-grids. In order to test this technology a pilot plant was built in September 2015 in the rural village of ‘El Espino’.The Objective of this study is the evaluation of the current operation strategy of this micro-grid and the implementation of the project. To that end, monitoring data is used, covering the period 1 of January of 2016 to 31 of july of 2017.The data analysis shows that the average PV efficiency is 9.34 %, the efficiency of the diesel generator is 31.4 % and the round trip efficiency of the battery is 74%. Using the data collected and the techno-economic information of the place, the operation cost of the system for the analyzed period is computed. Finally, an optimal dispatch model based in a mixed-integer linear programming (MILP) is used to find the optimal energy flows in the system that minimize the diesel consumption