A Geometric Approach for Regularization of the Data Term in Stereo-Vision

Every stereovision application must cope with the correspondence problem. The space of the matching variables, often consisting of spatial coordinates, intensity and disparity, is commonly referred as the data term (space). Since the data is often noisy a-priori, preference is required to result a smooth disparity (or piecewise smooth). To this end, each local method (e.g. window correlation techniques) performs a regularization of the data space. In this paper we propose a geometric framework for anisotropic regularization of the data space seeking to preserve the discontinuities in this space when filtering out the noise. On the other hand, the global methods consider a non-regularized data term with a smoothing constraint imposed directly on the disparity. This paper also proposes a new idea where the data space is regularized in a global method prior to the disparity evaluation. The idea is implemented on the state of the art variational method. Experimental results on the Middlebury real images demonstrate the advantages of the proposed approach.

A Study of Users’ Reactions to a Mixed Online Discussion Model: A Lag Sequential Analysis Approach

There is an increasing growth of Social Network Services (SNSs). A variety of SNSs are applied in online interpersonal platforms. Among them, asynchronous and synchronous discussions are widely examined. However, there is a lack of research into the effects of integrated discussion services that combines asynchronous and synchronous discussions. Thus, the study investigates users’ performances and behavior patterns in a mixed discussion model that integrates asynchronous and synchronous discussions with a lag sequential analysis. The results showed that most groups chose to adopt the mixed discussion model (i.e., using both synchronous and asynchronous discussions), and only one group totally adopted the asynchronous discussion model. The study further analyzed the learners’ learning effectiveness and behavioral patterns, and the results indicated that the groups using the mixed model had a positive performance to a certain extent in terms of learning effectiveness and knowledge construction. In addition, users with the mixed discussion model demonstrated diverse behaviors, which were more complex than that of those with a single-way discussion model. Furthermore, regarding the groups using “balanced synchronous and asynchronous discussions” and the groups “mainly using synchronous discussion supplemented by less asynchronous discussion” in the mixed model (simultaneously using synchronous and asynchronous discussions), those users who mainly used synchronous discussion supplemented by asynchronous discussion had more diverse behaviors of knowledge construction.     

A Standard Model—Theoretic Approach to Operational Semmantics of Recursiv Programs

In this paper we try to introduce a new approach to operational semantics of recursive programs by using ideas in the“priority method”which is a fundamental tool in Recursion Theory.In lieu of modelling partial functions by introducing undefined values in a traditional approach,we shall define a priority derivation tree for every term,and by respecting thr rule“attacking the subtem of the highest priority first”we define transition relations,computation sequences etc.directly based on a standard interpretation whic includes no undefined value in its domain,Finally,we prove that our new approach generates the same opeational semantics as the traditional one.It is also pointed out that we can use our strategy oto refute a claim of Loeckx and Sieber that the opperational semantics of recursive programs cannot be built based on predicate logic.     

A Guaranteed Deterministic Approach to Superhedging: Financial Market Model,Trading Constraints,and the Bellman–Isaacs Equations

Automation and Remote Control - A guaranteed deterministic problem setting of superreplication in discrete time is proposed as an alternative to the traditional probabilistic approach based on the...     

MIDCA - A Discretization Model for Data Preprocessing in Data Mining

Decision tree is one of the most widely used and practical methods in data mining and machine learning discipline. However, many discretization algorithms developed in this field focus on univariate only, which is inadequate to handle the critical problems especially owned by medical domain. In this paper, we propose a new multivariate discretization method called Multivariate Interdependent Discretization for Continuous Attributes - MIDCA. Our algorithm can minimize the uncertainty between the interdependent attribute and the continuous-valued attribute, and at the same time maximize their correlation. The experimental results demonstrate a comparison of performance of various decision tree algorithms on twelve real-life datasets from UCI repository.     

Digital Piracy: Factors that Influence the Intention to Pirate – A Structural Equation Model Approach

Faster Internet connections are breaking most of the geographic barriers. At the same time, the huge digital content that have been generated in last years is motivating new forms of digital piracy. We know that piracy of copyrighted digital material has a huge impact on countries’ economy, being a major issue for the whole society and not only for content creators. The purpose of this paper is to investigate digital piracy intention. For that purpose, we have expanded the framework of the theory of planned behavior using the utility theory, the deterrence theory and other relevant constructs. Using data from students of a Portuguese university and high school, a sample of 590 questionnaires has been collected. Two models were developed and analyzed using structural equation modeling. The first considers the full sample (Full Model), while the second considers only those who had pirated (Pirate Model). The pirate model confirmed the existence of a significant and strong relation between past behavior and intention toward digital piracy.     

A Model-free Approach to Fault Detection of Continuous-time Systems Based on Time Domain Data

In this paper, a model-free approach is presented to design an observer-based fault detection system of linear continuoustime systems based on input and output data in the time domain. The core of the approach is to directly identify parameters of the observer-based residual generator based on a numerically reliable data equation obtained by filtering and sampling the input and output signals.     

A New Approach to the Analysis of Non-recurrent Ladder Networks†

A new approach to the analysis of the non-recurrent ladder network is presented. Using the converse of the conventional specification for the series and shunt branches, a rapid method of analysis is evolved. The rules governing the combination of the series admittances and shunt impedances are shown to be of an extremely simple nature and easier to apply than those pertaining to the conventional specification. In addition, unlike in the latter case, the same rules apply to both voltage ratio and transfer impedance.     

A Bilinear Approach to the Parameter Estimation of a General Heteroscedastic Linear System,with Application to Conic Fitting

In this paper, we employ low-rank matrix approximation to solve a general parameter estimation problem: where a non-linear system is linearized by treating the carrier terms as separate variables, thereby introducing heteroscedastic noise. We extend the bilinear approach to handle cases with heteroscedastic noise, in the framework of low-rank approximation. The ellipse fitting problem is investigated as a specific example of the general theory. Despite the impression given in the literature, the ellipse fitting problem is still unsolved when the data comes from a small section of the ellipse. Although there are already some good approaches to the problem of ellipse fitting, such as FNS and HEIV, convergence in these iterative approaches is not ensured, as pointed out in the literature. Another limitation of these approaches is that they cannot model the correlations among different rows of the “general measurement matrix”. Our method, of employing the bilinear approach to solve the general heteroscedastic parameter estimation problem, overcomes these limitations: it is convergent, at least to a local optimum, and can cope with a general heteroscedastic problem. Experiments show that the proposed bilinear approach performs better than other competing approaches: although it is still far short of a solution when the data comes from a very small arc of the ellipse.

A Systematic Analysis Approach to Discrete-time Indirect Model Reference Adaptive Control

This paper presents the design and analysis of indirect model reference adaptive control （MRAC） with normalized adaptive law for a class of discrete-time systems. The main work includes three parts. Firstly, the constructed plant parameter estimation algorithm not only possesses the same properties as those of traditional estimation algorithms but also avoids the possibility of division by zero. Secondly, by finding the relationship between the plant parameter estimate and controller parameter estimate and using the properties of plant parameter estimate, the similar properties of controller parameter estimate are also established. Thirdly, based on the relationship properties between the normalizing signal and all the signals in the closed-loop system and on some important mathematical tools on discrete-time systems, as in the continuous-time case, a systematic stability and convergence analysis approach to the discrete indirect MRAC scheme is developed rigorously.     

Correction to: Is it possible to disregard obsolete requirements? A family of experiments in software effort estimation

Requirements Engineering - A correction to this paper has been published: https://doi.org/10.1007/s00766-021-00354-4     

Is the Leading Role Desirable?: A Simulation Analysis of the Stackelberg Behavior in World Petroleum Market

This article explores extraction profiles in the Stackelberg equilibrium of exhaustible resource industry. Calibrated with real data of world petroleum market, the Stackelberg and Cournot–Nash equilibriums are solved numerically. The properties of the Stackelberg equilibrium are compared and contrasted with the benchmark open-loop Cournot–Nash equilibrium. Simulation results indicate that the leader’s gains are limited in the Stackelberg strategic setting. Methodologically, this article pioneers solving the Stackelberg game numerically in a dynamic and empirical model.     

Mental rotation: a key to mitigation of motion sickness in the virtual environment?

Some of our recent observations suggest that mental rotation may be important for reduction of motion sickness in microgravity as well as in the microgravity simulator. Therefore, we suggest that development of the ability to perform mental rotation may be important for adaptation to many virtual environments. Training virtual environment operators to perform mental rotation may enhance operator performance both by increasing their ability to "locomote in" and manipulate that environment and by reducing motion sickness associated with transitions between virtual and normal environments.     

A Cost-Efficient Approach to Storing Users’ Data for Online Social Networks

Journal of Computer Science and Technology - As users increasingly befriend others and interact online via their social media accounts, online social networks (OSNs) are expanding rapidly....     

Data Management in Peer-to-Peer Environment: A Perspective of BestPeer

Peer-to-Peer (P2P) systems have attracted much attention in academic commu-nity and industry circles due to their promising applications in various domains. This paper presents the authors‘ research efforts on introducing complex query capabilities in a P2P environ-ment consisting of numerous peers with large volume of data. An underlying hybrid P2P computing platform, named BestPeer is described first. The connection among peers within BestPeer is self-configurable through maintaining the nearest neighbor of peers, and the agent techniques employed in the system ensure its capability of providing sophisticated services. The designs of three P2P data management systems which are all based on BestPeer are described in detail. They provide support for information retrieval, query processing and Web services respectively. Advantages and limitations are discussed, while ongoing work is presented. Current systems can provide basic functions for keyword-based search, SQL-like query processing, and Web services querying and discovery. Some further topics on providing fully-fledged data management functionalities for P2P distributed computing systems with security guarantee are also discussed.     

A Direct Approach to Computing theμ-basis of Planar Rational Curves

This paper presents an O(n²) algorithm, based on Gröbner basis techniques, to compute the μ -basis of a degree n planar rational curve. The prior method involved solving a set of linear equations whose complexity by standard numerical methods was O(n³). The μ -basis is useful in computing the implicit equation of a parametric curve and can express the implicit equation in the form of a determinant that is smaller than that obtained by taking the resultant of the parametric equations.     

Single-Velocity Model of Two-Phase Liquids for Calculating Flows According to the First Principles’ Approach

A single velocity model of one-component media for calculating two-phase flows is presented. The model is based on conservation laws with minimal additional assumptions. The model and numerical method are intended for the direct numerical simulation (DNS) of complex two-phase flows with high-performance computing systems (exascale computing). The closed set of governing equations is written for nonaveraged parameters (so-called microparameters) and for a medium with a complex equation of state. It is assumed that each point of the flow is completely characterized by a single density, single velocity, and single internal energy. The diffused interface model is used for describing an interphase boundary. A method for generating the relationship between thermodynamic functions and all possible values of density and internal energy is presented. The real functions for the pure phases are used. The hydrodynamic basis of the model consists of Navier-Stokes equations or Euler equations that take heat conductivity processes into consideration. The reliability of the model is tested on a 1D problem for real water, in particular, on the Stefan problem and on the problem on the formation and coalescence of bubbles.     

A Fuzzy Approach to Classification of Text Documents

This paper discusses the classification problems of text documents. Based on the concept of the proximity degree, the set of words is partitioned into some equivalence classes.Particularly, the concepts of the semantic field and association degree are given in this paper.Based on the above concepts, this paper presents a fuzzy classification approach for document categorization. Furthermore, applying the concept of the entropy of information, the approaches to select key words from the set of words covering the classification of documents and to construct the hierarchical structure of key words are obtained.