Contextual Refinement Types

We develop an extension of the proof environment Beluga with datasort refinement types and study its impact on mechanized proofs. In particular, we introduce refinement schemas, which provide fine-grained classification for the structures of contexts and binders. Refinement schemas are helpful in concisely representing certain proofs that rely on relations between contexts. Our formulation of refinements combines the type checking and sort checking phases into one by viewing typing derivations as outputs of sorting derivations. This allows us to cleanly state and prove the conservativity of our extension.Comment: In Proceedings LFMTP 2023, arXiv:2311.0991

Exploring Context with Deep Structured models for Semantic Segmentation

State-of-the-art semantic image segmentation methods are mostly based on training deep convolutional neural networks (CNNs). In this work, we proffer to improve semantic segmentation with the use of contextual information. In particular, we explore `patch-patch' context and `patch-background' context in deep CNNs. We formulate deep structured models by combining CNNs and Conditional Random Fields (CRFs) for learning the patch-patch context between image regions. Specifically, we formulate CNN-based pairwise potential functions to capture semantic correlations between neighboring patches. Efficient piecewise training of the proposed deep structured model is then applied in order to avoid repeated expensive CRF inference during the course of back propagation. For capturing the patch-background context, we show that a network design with traditional multi-scale image inputs and sliding pyramid pooling is very effective for improving performance. We perform comprehensive evaluation of the proposed method. We achieve new state-of-the-art performance on a number of challenging semantic segmentation datasets including $NYUDv2$, $PASCAL$-$VOC2012$, $Cityscapes$, $PASCAL$-$Context$, $SUN$-$RGBD$, $SIFT$-$flow$, and $KITTI$ datasets. Particularly, we report an intersection-over-union score of $77.8$ on the $PASCAL$-$VOC2012$ dataset.Comment: 16 pages. Accepted to IEEE T. Pattern Analysis & Machine Intelligence, 2017. Extended version of arXiv:1504.0101

A Survey of Requirements Engineering Methods for Pervasive Services

Designing and deploying ubiquitous computing systems, such as those delivering large-scale mobile services, still requires large-scale investments in both development effort as well as infrastructure costs. Therefore, in order to develop the right system, the design process merits a thorough investigation of the wishes of the foreseen user base. Such investigations are studied in the area of requirements engineering (RE). In this report, we describe and compare three requirements engineering methods that belong to one specific form of RE, namely Goal-Oriented Requirements Engineering. By mapping these methods to a common framework, we assess their applicability in the field of ubiquitous computing systems

Information encountering re-encountered: A conceptual re-examination of serendipity in the context of information acquisition

Purpose In order to understand the totality, diversity and richness of human information behavior, increasing research attention has been paid to examining serendipity in the context of information acquisition. However, several issues have arisen as this research subfield has tried to find its feet; we have used different, inconsistent terminology to define this phenomenon (e.g. information encountering, accidental information discovery, incidental information acquisition), the scope of the phenomenon has not been clearly defined and its nature was not fully understood or fleshed-out. Design/methodology/approach In this paper, information encountering (IE) was proposed as the preferred term for serendipity in the context of information acquisition. Findings A reconceptualized definition and scope of IE was presented, a temporal model of IE and a refined model of IE that integrates the IE process with contextual factors and extends previous models of IE to include additional information acquisition activities pre- and postencounter. Originality/value By providing a more precise definition, clearer scope and richer theoretical description of the nature of IE, there was hope to make the phenomenon of serendipity in the context of information acquisition more accessible, encouraging future research consistency and thereby promoting deeper, more unified theoretical development