Guilherme Lima

IBM · IBM Research Brazil

ULKB Logic is an open-source framework written in Python for reasoning over knowledge graphs. It provides an interactive theorem prover-like environment equipped with a higher-order language similar to the one used by HOL Light. The main goal of ULKB Logic is to ease the construction of applications that combine state-of-the-art computational logic...

Using reinforcement learning for automated theorem proving has recently received much attention. Current approaches use representations of logical statements that often rely on the names used in these statements and, as a result, the models are generally not transferable from one domain to another. The size of these representations and whether to i...

We describe how we used a Triple Pattern Fragments (TPF) interface and the Comunica knowledge graph querying framework to enable live SPARQL queries over ConceptNet, one of largest knowledge graphs for commonsense reasoning publicly available on the Web. Despite being a Linked Data resource, the official ConceptNet is not published in RDF and does...

Using reinforcement learning for automated theorem proving has recently received much attention. Current approaches use representations of logical statements that often rely on the names used in these statements and, as a result, the models are generally not transferable from one domain to another. The size of these representations and whether to i...

The knowledge graph completion task has gained a lot of attention in recent years, especially with the use of machine learning (ML). However, most of the work has focused on the structure of the graph while ignoring the data it describes. In this demo, we present an approach that does the opposite: it leverages the multimodal data described by a kn...

Knowledge Base Question Answering (KBQA) tasks that involve complex reasoning are emerging as an important research direction. However, most existing KBQA datasets focus primarily on generic multi-hop reasoning over explicit facts, largely ignoring other reasoning types such as temporal, spatial, and taxonomic reasoning. In this paper, we present a...

We present an approach for practical rule-based temporal reasoning over RDF/OWL using Allen’s Interval Algebra (IA). Reasoning in Allen’s IA is only tractable for certain subalgebras and is done through path-consistency, a constraint propagation algorithm whose rule-based implementation requires \(O(n^2)\) rules for a subalgebra with n relations. O...

Methods based on Machine Learning have become state-of-the-art in various segments of computing, especially in the fields of computer vision, speech recognition, and natural language processing. Such methods, however, generally work best when applied to specific tasks in specific domains where large training datasets are available. This paper prese...

This paper showcases the Cycle Orchestrator, a microservices infrastructure designed to structure and manage workflows related to heterogeneous data, through a knowledge-based perspective. It aims at leveraging reasoning, explainability and collaboration among users over experiments that comprise workflow executions. We briefly discuss about design...

In this paper, we give an overview of the semantic gap problem in multimedia and discuss how machine learning and symbolic AI can be combined to narrow this gap. We describe the gap in terms of a classical architecture for multimedia processing and discuss a structured approach to bridge it. This approach combines machine learning (for mapping sign...

In this chapter, we give an introduction to symbolic artificial intelligence (AI) and discuss its relation and application to multimedia. We begin by defining what symbolic AI is, what distinguishes it from non-symbolic approaches, such as machine learning, and how it can used in the construction of advanced multimedia applications. We then introdu...

This short course is an introduction to symbolic artificial intelligence (AI) applied to multimedia. We assume no previous knowledge of AI and only basic knowledge of multimedia. The short course is divided into three parts. In the first part, we present general notions of AI and discuss the challenges involved in the construction of intelligent mu...

The use of semantic descriptions in data intensive domains require a systematic model for linking semantic descriptions with their manifestations in fragments of heterogeneous information and data objects. Such information heterogeneity requires a fragment model that is general enough to support the specification of anchors from conceptual models t...

Céu is a synchronous programming language for embedded soft real-time systems. It focuses on control-flow safety features in the presence of shared-memory concurrency and abortion of lines of execution, while enforcing memory-bounded, deterministic, and terminating reactions to the environment. In this work, we present a small-step structural opera...

We describe how we modified an NCL player to accept as input, in addition to NCL documents, Lua scripts. These Lua scripts evaluate to a table in a particular format, called NCL-ltab, which is a Lua table encoding of the NCL player's internal model. One advantage of our modifications is that they allow the NCL parsing to occur in the Lua script, i....

In this paper we present an ongoing research that aims to produce a model to predict success in the musical market. To reach this goal, it is necessary, initially, to identify infl uence factors in the market, which is the current focus of this research. In this branch, we identify that tweets have infl uence over the popularity of an album in Spot...

Céu is a synchronous programming language for embedded soft real-time systems. It focuses on control-flow safety features, such as safe shared-memory concurrency and safe abortion of lines of execution, while enforcing memory bounded, deterministic, and terminating reactions to the environment. In this work, we present a small-step structural opera...

Céu is a synchronous programming language for embedded soft real-time systems. It focuses on control-flow safety features, such as safe shared-memory concurrency and safe abortion of lines of execution, while enforcing memory bounded, deterministic, and terminating reactions to the environment. In this work, we present a small-step structural opera...

We propose two extensions for a state-of-the-art method of rollback-recovery in distributed CEP (complex event processing). In CEP, an operator network is used to search for patterns in events streams. Sometimes these operators fail and lose their state. Rollback-recovery is a method for dealing with such state losses. The type of rollback-recovery...

Since the early 1990's, the TeleMídia laboratory of the Department of Informatics of PUC-Rio researches and trains people in the areas of multimedia and hypermedia, which include interactive videos and video collaboration as important subareas. This chapter presents the main research lines and projects of the laboratory and discusses the future vis...

In this paper, we present the conversion of NCL to Smix and discuss its main implications. NCL is a declarative language for the specification of interactive multimedia presentations which was adopted by the ITU-T H.761 recommendation for interoperable IPTV services. Smix is a synchronous domain-specific language with a similar purpose, but with a...

The semantics of current multimedia languages is informal and may lead to the development of ambiguous applications. In this paper we investigate the use of the synchronous language Céu for programming local multimedia applications, in particular, those applications that can be described as a set of synchronized media objects. Céu has a determinist...

This short course is an introduction to GStreamer, one of the main free/open-source frameworks for multimedia processing. We start presenting GStreamer, its architecture and the dataflow programming model, and then adopt a hands-on approach. Starting with an example, a simple video player, we introduce the main concepts of GStreamer’s basic C API a...

We present a graphics architecture for the seamless integration of 3DV objects into ordinary 2D/3D multimedia applications. The architecture is based on layered-depth-image (LDI) and supports the real-time rendering of multiple views for multi-view 3D displays. We also present a prototype implementation of the proposed architecture in OpenCL, and d...

The presentation of multimedia content requires devices with proper computational resources to guarantee intermedia synchronization requirements. When a multimedia system is executed in resource-constrained devices, some synchronization mismatches may occur. This problem becomes harder to solve when considering support for features like user intera...

In this paper, we investigate the problem of normal forms for links and connectors in NCL 3.0. We identify two such forms, called the First and Second Normal Forms (NF1 and NF2), in which links and connectors appear in simple terms. We also present normalization procedures (proofs), which show that for every NCL~3.0 program, there is an equivalent...

In this paper, we present an approach for reducing the complexity of NCL player implementations. This approach consists, basically, in introducing in the player's architecture an initial conversion step that removes all syntactic sugar and reuse features from the source language. The output of this step, a redundancy-free version of the original in...

There are many aspects concerned with the management of intra-media and inter-media synchronization of hypermedia application presentations. This paper revisits the integrated inter-media and intra-media synchronization model proposed and implemented by the NCL Player architecture as a specialization of a generic QoS orchestration framework. Some h...

In this paper, we describe the first steps towards the definition of the new NCL (Nested Context Language) 3.1 profile, called Raw profile, aiming at a more efficient and more reliable implementation of the Ginga-NCL presentation Engine. The new profile also allows the definition of a new transfer syntax notation, which will smooth the progress of...