Informatics

Multi-hop-based opportunistic concurrent directional transmission in 60 GHz WPANs
In millimeter Wave wireless personal area networks (mmWave WPANs), the design of efficient concurrent transmission considered high modulations up to a few Gbps is one of the most challenging issues. Even for the concurrent transmission over mmWave networks, the use of directional antenna is highly recommended to guarantee high modulations and to overcome short propagation range caused to high p...


Design patterns for context-aware services
Numerous context-aware applications were proposed in the literature. Relatively, little attention was paid to understanding how they are related. This paper introduces a framework for classifying context-aware services. We studied 48 context-aware service scenarios discussed in the literature, deriving a model of seven design patterns for context-aware services. This paper discusses the model a...
Objective blur assessment based on contraction errors of local contrast maps
Blur distortion appears in multimedia content due to acquisition, compression or transmission errors. In this paper, a method is proposed to predict blur severity based on the contraction errors of local contrast maps. The proposed method is developed from the observation that histogram distribution of natural image would contract according to the degree of blur distortion. In order to quantify...


Accelerating IP routing algorithm using graphics processing unit for high speed multimedia communication
This paper presents a Graphics Processing Unit (GPU)-based implementation of a Bellman-Ford (BF) routing algorithm using NVIDIA’s Compute Unified Device Architecture (CUDA). In the proposed GPU-based approach, multiple threads run concurrently over numerous streaming processors in the GPU to dynamically update routing information. Instead of computing the individual vertex distances one-by-on...
Least squares approach for the time-dependent nonlinear Stokes–Darcy flow
A time-dependent nonlinear model of Stokes–Darcy flows is considered for numerical approximations by an optimization based domain decomposition method. The coupled system is formulated as a constrained optimal control problem, where a Neumann type control is introduced to enforce boundary conditions on the interface of subdomains. a computational algorithm is discussed for the least squares f...


Improving search over Electronic Health Records using UMLS-based query expansion through Random Walks
Most of the information in Electronic Health Records (EHRs) is represented in free textual form. Practitioners searching EHRs need to phrase their queries carefully, as the record might use synonyms or other related words. In this paper we show that an automatic query expansion method based on the Unified Medicine Language System (UMLS) Metathesaurus improves the results of a robust baseline wh...
Effective and precise face detection based on both grey-level image and depth map
In this work an effective face detector based on the well-known Viola-Jones algorithm is proposed. A common issue in face detection is that for maximizing the face detection rate a low threshold is used for classifying as face an input image, but at the same time using a low threshold drastically increases the number of false positives. In this paper several criteria are proposed for reducing f...

Low-dimensional tracking of association structures in categorical data
In modern applications, such as text mining and signal processing, large amounts of categorical data are produced at a high rate and are characterized by association structures changing over time. Multiple correspondence analysis (MCA) is a well established dimension reduction method to explore the associations within a set of categorical variables. A critical step of the MCA algorithm is a sin...
On spherical harmonics based numerical quadrature over the surface of a sphere
It has been suggested in the literature that different quasi-uniform node sets on a sphere lead to quadrature formulas of highly variable quality. We analyze here the nature of these variations, and describe an easy-to-implement least-squares remedy for previously problematic cases. Quadrature accuracies are then compared for different node sets ranging from fully random to those based on Gauss...

A model predictive control framework for reliable microgrid energy management
This paper proposes a framework for reliable microgrid energy management based on receding horizon control. A microgrid is considered for exemplification, connected to an external grid via a transformer and containing a local consumer, a renewable generator (wind turbine) and a storage facility (battery). Optimal scheduling of battery is sought for minimizing costs. To this aim, a predictive co...
An integrated simulation model for analysing electricity and gas systems
This paper aims at analysing the impacts of interdependencies between electricity and natural gas systems in terms of security of energy supply. When analysing both systems several interdependencies can be observed, however, the most significant interdependencies are as follows: (1) gas dependency of gas fired power plants in electricity system and electric dependency of electric-driven compres...

Learning strategies in table tennis using inverse reinforcement learning
Learning a complex task such as table tennis is a challenging problem for both robots and humans. Even after acquiring the necessary motor skills, a strategy is needed to choose where and how to return the ball to the opponent’s court in order to win the game. The data-driven identification of basic strategies in interactive tasks, such as table tennis, is a largely unexplored problem. In thi...
Community, tools, and practices in web archiving: The state-of-the-art in relation to social science and humanities research needs
The web encourages the constant creation and distribution of large amounts of information; it is also a valuable resource for understanding human behavior and communication. To take full advantage of the web as a research resource that extends beyond the consideration of snapshots of the present, however, it is necessary to begin to take web archiving much more seriously as an important element...
Coherent sources direction finding and polarization estimation with various compositions of spatially spread polarized antenna arrays
Various compositions of sparsely polarized antenna arrays are proposed in this paper to estimate the direction-of-arrivals (DOAs) and polarizations of multiple coherent sources. These polarized antenna arrays are composed of one of the following five sparsely spread sub-array geometries: (1) four spatially spread dipoles with three orthogonal orientations, four spatially spread loops with three...
A spline filter for multidimensional nonlinear state estimation
The problem of nonlinear/non-Gaussian filtering has generated significant interest in the literature. The effectiveness of a nonlinear/non-Gaussian filtering algorithm depends on the accurate representation of the probability density function of the system state. The Extended Kalman Filter (EKF), the Approximate Grid Based methods (AGBM), and particle based filters have been developed to solve ...