FCT: DI - Documentos de conferências internacionais
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- Conversational Search with Random Walks over Entity GraphsPublication . Gonçalves, Gustavo; Magalhães, João; Callan, Jamie; NOVALincsThe entities that emerge during a conversation can be used to model topics, but not all entities are equally useful for this task. Modeling the conversation with entity graphs and predicting each entity's centrality in the conversation provides additional information that improves the retrieval of answer passages for the current question. Experiments show that using random walks to estimate entity centrality on conversation entity graphs improves top precision answer passage ranking over competitive transformer-based baselines.
- Efficient Synchronization-Light Work StealingPublication . Custódio, Rafael; Paulino, Hervé; Rito, Guilherme; DI - Departamento de InformáticaWork Stealing (Ws) is a provably efficient scheduler of parallel computations. In WS each processor owns a deque that it uses as a call stack; when out of work, processors try to steal tasks from other processors' deques. Unfortunately, the concurrent nature of processors' deques entails expensive synchronization even when processors access their own deques. Recently, Rito and Paulino have found that the use of split deques allows to provably avoid most synchronization costs while keeping WS's asymptotically optimal expected runtime; in Low-Cost Work Stealing (LCWS) - the variant of WS introduced in their work - processors need not synchronization for most local accesses to their (split) deques. In this paper we assess the concrete efficiency gains of LCWS in practice. More concretely, we implemented LCWS in the Parlay library and show how it compares against Parlay's original work stealing algorithm on the execution of the benchmarks from the Problem-Based Benchmark Suite (PBBS). Experimental results show that our signal-based LCWS implementation obtains speedups with regard to WS for at least 65% of PBBS' benchmarks in three different computers.
- Enriching Kademlia by PartitioningPublication . Monteiro, João; Costa, Pedro Akos; Leitão, João; De La Rocha, Alfonso; Psaras, Yiannis; DI - Departamento de Informática; NOVALincsDecentralizing the Web is becoming an increasingly interesting endeavor that aims at improving user security and privacy as well as providing guaranteed ownership of content. One such endeavor that pushes towards this reality, is Protocol Labs' Inter-Planetary File System (IPFS) network, that provides a decentralized large scale file system to support the decentralized Web. To achieve this, the IPFS network leverages the Kademlia DHT to route and store pointers to content stored by network members (i.e., peers). However, due to the large number of network peers, content, and accesses, the DHT routing needs to be efficient and quick to enable a decentralized web that is competitive. In this paper, we present work in progress that aims at improving the Kademlia DHT performance through the manipulation of DHT identifiers by adding prefixes to identifiers. With this, we are able to bias the DHT topological organization towards locality (which can be either geographical or applicational), which creates partitions in the DHT and enables faster and more efficient query resolution on local content. We designed prototypes that implement our proposal, and performed a first evaluation of our work in an emulated network testbed composed of 5000 nodes. Our results show that our proposal can benefit the DHT look up on data with locality with minimal overhead.
- Towards a non-functional requirements discovery approach for persuasive systemsPublication . Condori-Fernandez, Nelly; Araujo, João; Catala, Alejandro; Lago, Patricia; NOVALincs; DI - Departamento de InformáticaA number of software systems that attempt to help people achieve behavior change have been proposed in various domains such as health and wellness. However, sometimes, such systems have failed to provide a satisfactory or sustainable User Experience (UX), as it is observed when users may be reluctant to respond to the activation of the systems' changing demands. Moreover, a negative User Experience (UX) can be exposed by Behavior Change Support Systems (BCSS) if designers do not have clear understanding of the requirements that factually help changing the user behavior that accomplishes a sustainability goal. We first explored the Persuasive System Design (PSD) model that should be considered in UX assessment of BCSSs. Then, we propose a requirements discovery process that can be considered to redesign a software interactive system based on negative UX.
- Overlay Networks for Edge ManagementPublication . Costa, Pedro Akos; Fouto, Pedro; Leitão, João; DI - Departamento de Informática; NOVALincsEdge computing has emerged as a solution to address existing limitations of cloud computing for bandwidth-heavy and time-sensitive applications, by moving (some) computations from bandwidth saturated Cloud infrastructures closer to client devices, where data is effectively produced and consumed. However, existing materializations of the edge computing paradigm take limited advantage of computational and storage power that exists in the edge and between client devices and the cloud. Most of these leverage static hierarchical topologies (e.g., Fog Computing) to pre-process data before sending it to the Cloud, which limits the advantages that can be extracted from the edge computing paradigm. In the past, peer-to-peer systems have sought to tackle the challenges of increasing scalability and availability for very large systems, with a large number of solutions being proposed namely, distributed overlay networks for resource management. In this paper, we argue that the clever adaptation of peer-to-peer solutions can enable novel applications to fully exploit the potential of the edge. In particular, we study the viability of taking advantage of specialized overlay networks in edge environments to enable the management of a large number of computational resources. Contrary to previous proposals, that assume the environment to be composed of mostly homogeneous devices, our proposal embraces existing heterogeneity and exploits the location of computational resources to devise a (partially) self-organizing overlay network that can be exploited both to provide membership information to applications, but also do efficiently disseminate management information across edge devices. We have conducted an experimental evaluation using container-based emulation in an heterogeneous network composed by 100 devices, with results showing that our protocol is able to maximize the bandwidth usage of the system, allowing more data to flow throughout the network, while retaining high robustness to failures.
- The BioVisualSpeech Serious Game with Voice Exercises for People with Parkinson's Disease with Hypokinetic DysarthriaPublication . Viana, Tiago; Cavaco, Sofia; NOVALincs; DI - Departamento de InformáticaPeople with Parkinson's disease (PD) can have dysarthria, a voice disorder that affects speech intelligibility. To fight this disorder people may resort to speech and language therapy. Unfortunately, weekly speech therapy sessions may not be enough, because to achieve and maintain good voice quality, intensive training is required. Additionally, the COVID-19 pandemic brought attention to the need for alternative speech therapy treatments that complement face-to-face appointments. Here, we propose a serious therapy game to improve voice loudness that can be used for intensive therapy or when face-to-face appointments are not possible. The game integrates three voice exercises used in speech therapy sessions for people with PD and aims to provide motivation for patients to perform the exercises on a daily basis. This application evaluates the vocal intensity, vocal frequency and maximum phonation time, offering real-time visual feedback. It also allows pathologists to customize the exercises difficulty to the needs of each patient.
- Customizable Serious Speech Therapy Games with Dynamic Difficulty Adjustment for Children with SigmatismPublication . Martins, Sofia; Cavaco, Sofia; DI - Departamento de Informática; NOVALincsChildren with speech sound disorders should attend speech and language therapy and should practice the speech exercises regularly to surpass their speech difficulties. Since doing the speech exercises often may be tedious, there is the need to motivate children to practice them. During the COVID-19 pandemic, speech and language pathologists had the need to adapt their procedures to others with less physical contact. Here, we propose two serious games to motivate children with sigmatism on doing the speech exercises, which can be used at home and during face-to-face and online speech therapy sessions. The games use automatic speech recognition to classify speech productions. Visual and auditory feedback are used to help children understand their performance, and a hint system is used to help them perform the exercises correctly. A dynamic difficulty adjustment system is used to change the level of difficulty according to the child's speech performance in previous trials.
- NIME's ScorePublication . Masu, Raul Giancarlo Maria; Correia, Nuno N.; Romão, Teresa; DI - Departamento de Informática; NOVALincsThis paper investigates how the concept of score has been used in the NIME community. To this end, we performed a systematic literature review of the NIME proceedings, analyzing papers in which scores play a central role. We analyzed the score not as an object per se but in relation to the users and the interactive system(s). In other words, we primarily looked at the role that scores play in the performance ecology. For this reason, to analyze the papers, we relied on ARCAA, a recent framework created to investigate artifact ecologies in computer music performances. Using the framework, we created a scheme for each paper and clustered the papers according to similarities. Our analysis produced five main categories that we present and discuss in relation to literature about musical scores.
- A mobile system to increase efficiency of the lecturers when preventing academic dishonesty during written examsPublication . Maroco, Pedro; Cambeiro, João; Amaral, Vasco; DI - Departamento de Informática; NOVALincsThe process of in-class control and monitoring of students' examination activities is traditionally conducted manually, without the support of technology. The workflow can include tasks for attendance record or dishonesty control. The tasks include identifying the students before, during and after the beginning of the evaluation activity. Can also include examination room allocation to the activity, as well as the distribution of students per available examination rooms and distribution of students inside the room according to a classroom seating plan (which can have a varied setup). However, with a large number of students, the execution of these tasks becomes challenging to perform efficiently, requiring innovative techniques or tools to support them effectively. In this work, we propose the design and implementation of a mobile system based on IoT technology and MIFARE student's cards to support the lecturer efficiently during the examination workflow. We propose the use of current indoor location technology, and we build a proof of concept prototype, validating it in a real educational environment.
- Improving the Usability of a MAS DSMLPublication . Miranda, Tomás; Challenger, Moharram; Tezel, Baris Tekin; Alaca, Omer Faruk; Barišić, Ankica; Amaral, Vasco; Goulão, Miguel; Kardas, Geylani; NOVALincs; DI - Departamento de InformáticaContext: A significant effort has been devoted to the design and implementation of various domain-specific modeling languages (DSMLs) for the software agents domain. Problem: Language usability is often tackled in an ad-hoc way, with the collection of anecdotal evidence supporting the process. However, usability plays an important role in the productivity, learnability and, ultimately, in the adoption of a MAS DSML by agent developers. Method: In this chapter, we discuss how the principles of The “Physics” of Notations (PoN) can be applied to improve the visual notation of a MAS DSML, called SEA_ML and evaluate the result in terms of usability. Results: The evolved version of the language, SEA_ML++, was perceived as significantly improved in terms of icons comprehensibility, adequacy and usability, as a direct result of employing the principles of PoN. However, users were not significantly more efficient and effective with SEA_ML++, suggesting these 2 properties were not chiefly constrained by the identified shortcomings of the SEA_ML concrete syntax.