Abstract
During the last few years many initiatives were taken away in response to high levels of energy consumption verified in data centers. We all know that this is a critical issue nowadays. Many studies carried out raised a lot of concerns about the energy demands of data centers, discussing solutions to reduce it effectively without affecting their day-by-day operation. In this work we made a small contribution to help that. We studied in a data warehousing system how could be possible to establish an energy consumption plan for a star-query. With these plans, we can establish in each phase of a star-query execution the energy consumed by all the elementary tasks that were executed to satisfy it. With this purpose in mind, and motivated by the usual methods and heuristics used on query execution optimization, we designed and developed a method to estimate the energy consumption of each element (operator) integrated in the execution plan of a query at compile time. With it, we also build up the corresponding energy consumption used on executing the star-query, taking into consideration the characteristics of the computational platforms used for.

Abstract
Language designers usually need to implement parsers and printers. Despite being two related programs, in practice they are designed and implemented separately. This approach has an obvious disadvantage: as a language evolves, both its parser and printer need to be separately revised and kept synchronised. Such tasks are routine but complicated and error-prone. To facilitate these tasks, we propose a language called BiYacc, whose programs denote both a parser and a printer. In essence, BiYacc is a domain-specific language for writing putback-based bidirectional transformations - the printer is a putback transformation, and the parser is the corresponding get transformation. The pairs of parsers and printers generated by BiYacc are thus always guaranteed to satisfy the usual round-trip properties. The highlight that distinguishes this reflective printer from others is that the printer - being a putback transformation - accepts not only an abstract syntax tree but also a string, and produces an updated string consistent with the given abstract syntax tree. We can thus make use of the additional input string, with mechanisms such as simultaneous pattern matching on the view and the source, to provide users with full control over the printing-strategies. Copyright © by the paper's authors. Copying permitted for private and academic purposes.

Abstract
Functional programmers are strong enthusiasts of modular solutions to programming problems. Since software characteristics such as readability or maintainability are often directly proportional to modularity, this programming style naturally contributes to the beauty of functional programs. Unfortunately, in return of this beauty we often sacrifice efficiency: modular programs rely, at runtime, on the creation, use and elimination of intermediate data structures to connect its components. In this tutorial paper, we study an advanced technique that attempts to retain the best of this two worlds: (i) it allows programmers to implement beautiful, modular programs (ii) it shows how to transform such programs, in a way that can be incorporated in a compiler, into programs that do not construct any intermediate structure. © 2019, Springer Nature Switzerland AG.

Abstract

Abstract
The development of ubiquitous computing (ubicomp) environments raises several challenges in terms of their evaluation. Ubicomp virtual reality prototyping tools enable users to experience the system to be developed and are of great help to face those challenges, as they support developers in assessing the consequences of a design decision in the early phases of development. Given the situated nature of ubicomp environments, a particular issue to consider is the level of realism provided by the prototypes. This work presents a case study where two ubicomp prototypes, featuring different levels of immersion (desktop-based versus CAVE-based), were developed and compared. The goal was to determine the cost/benefits relation of both solutions, which provided better user experience results, and whether or not simpler solutions provide the same user experience results as more elaborate one.

Abstract
Purpose - This paper aims to present the Modelery, a platform for collaborative repository to support model-based software development. The Modelery is a Web platform, composed both by a Web page and Web services for interoperability. Design/methodology/approach - By performing a study in the existing platforms, it was possible to achieve a set of issues to tackle. The issues enabled the possibility to define a set of requirements that allowed the authors to design a new platform, and to perform a model-driven software development process, which started from the requirements until reaching the final software solution. Findings - With this work, it was possible to perform a survey on the currently available artifacts repositories, categorize them and identify their shortcomings. This was essential to define the set of requirements for a new platform to overcome the identified issues. This process leads to a platform able to improve the currently available solutions, and validated in the scientific community. In this paper, the authors also explore the applications of the repository. First, they use the Modelery to replace an older model's repository. Second, they have enabled the communication between other tools and the Modelery via Web services. Originality/value - This work presents a new Web repository for software artifacts aimed at supporting researchers and software developers. The presented platform is an improvement over other platforms on the integration of artifacts repository, social functionalities and scientific publications integration. The authors conclude this paper by comparing the achieved platform in terms of functionalities, against the other analyzed platforms.