Abstract
There are many information retrieval tasks over the Web, which cannot be attended with a simple keyword-based lookup search. Such an important exploratory search problem is the comparison of two Web resources. To manually compare two data resources by looking for information from one Web page to another without any software support is inefficient and time-consuming. This paper discusses a solution to automatize the comparison of two data resources present in a RDF graph. In our work, we provide an improvement over the current state-of-the-art method, by reverse engineering SPARQL queries using a hashing based recursive procedure. We empirically verify how hashing could largely benefit in reducing the size of the returned query and hence making it practically comprehensible for users or agents to understand the similarity concepts returned.

Abstract

Abstract
Around the world, there is a great concern with the emission of greenhouse gases, creating great interest in turning the energy systems more sustainable. Multi-energy systems are considered as a potential solution to help to this cause and in recent years, it has gained much attention from both research and industry. In this paper, an optimization model is proposed to use the flexibility of multi-energy systems to mitigate the uncertainty associated with wind generation. The differences between the flexibility provided by multi-energy systems and electrical storage systems in the network were studied. The results prove that the flexibility of the multi-energy systems can benefit the system in several aspects and provide insights on which is the best approach to take full advantage of renewable resources even when a high degree of uncertainty is present.

Abstract

Abstract
In this work, we present an optimal mapper for OFDM with index modulation (OFDM-IM). By optimal we mean the mapper achieves the lowest possible asymptotic computational complexity (CC) when the spectral efficiency (SE) gain over OFDM maximizes. We propose the spectro-computational (SC) analysis to capture the trade-off between CC and SE and to demonstrate that an -subcarrier OFDM-IM mapper must run in exact time complexity. We show that an OFDM-IM mapper running faster than such complexity cannot reach the maximal SE whereas one running slower nullifies the mapping throughput for arbitrarily large . We demonstrate our theoretical findings by implementing an open-source library that supports all DSP steps to map/demap an-subcarrier complex frequency-domain OFDM-IM symbol. Our implementation supports different index selector algorithms and is the first to enable the SE maximization while preserving the same time and space asymptotic complexities of the classic OFDM mapper.

Abstract
Computer programming plays a relevant role in the digital age as a key competency for project leverage and a driver of innovation for today's modern societies. Despite its importance, this domain is also well known for their higher learning failure rates. In this context, the study of how computer programming is taught is fundamental to clarify the teaching-learning process and to ensure the sharing of the best practices. This paper presents a survey on computer programming teaching in the first-year courses of Portuguese Universities, more precisely, what is taught and how it is taught. The study focuses essentially on the following facets: The class characterization, the methodologies used and the languages/technologies taught. Based on these criteria, a survey was done which gathers information of 59 courses included in a wide range of Universities spread across Portugal. The results were collected and analyzed. Based on this analysis a set of conclusions were taken revealing some interesting results on the teaching methods and languages used which can be useful to support a discussion on this subject and, consequently, to find new paths to shape the future of programming teaching. 2012 ACM Subject Classification Social and professional topics ! Computer science education.