Search results for " programmi"

Study of a medium-size biological molecular association by means of a pair potential semiempirical approach: β-carboline-lumiflavin

1985

The molecular association between some substituted β-carbolines and a model flavin, lumiflavin, has been studied by means of a semiempirical approach proposed by Fraga based on a 1/R expansion of atom-atom pair potentials. Only stacked minima have been considered because of their possible biological interest. The calculations characterize 15 different minimum stacked conformations, most of them occurring in the complexes considered. The structural and energetic effects of 1–Me, 6–OH and 7–OH substituents of β-carboline are discussed. An equilibrium conformation involving geometric overlap between the pteridinic portion of flavin and the indole group of β-carboline is predicted to be the mos…

Toward a formalization of a two traders market with information exchange

2014

This paper shows that Hamiltonians and operators can also be put to good use even in contexts which are not purely physics based. Consider the world of finance. The work presented here {models a two traders system with information exchange with the help of four fundamental operators: cash and share operators; a portfolio operator and an operator reflecting the loss of information. An information Hamiltonian is considered and an additional Hamiltonian is presented which reflects the dynamics of selling/buying shares between traders. An important result of the paper is that when the information Hamiltonian is zero, portfolio operators commute with the Hamiltonian and this suggests that the dy…

2020

Abstract Interest in studying information systems discontinuance has been increasing lately, yet there is no consensus on what it means. To improve the situation, we conduct a comprehensive review of current literature on IS discontinuance and identify 55 studies published during 1991–2017 that specifically focus on the topic. Our conceptual analysis disentangles the process, content, and context of the phenomenon, revealing that over the course of a typical IS lifecycle, IS discontinuance may materialize at least in five distinct forms: rejection, regressive discontinuance, quitting, temporary discontinuance, and replacement. After elaborating their distinctions, we discuss their theoretic…

Adaptive memory programming for the dynamic bipartite drawing problem

2020

Abstract The bipartite drawing problem is a well-known NP-hard combinatorial optimization problem with numerous applications. The aim is to minimize the number of edge crossings in a two-layer graph, in which the edges are drawn as straight lines. We consider the dynamic variant of this problem, called the dynamic bipartite drawing problem (DBDP), which consists of adding (resp. or removing) vertices and edges to (resp. or from) a given bipartite drawing, thereby obtaining a new drawing with a layout similar to that of the original drawing. To solve this problem, we propose a tabu search method that incorporates adaptive memory to search the solution space efficiently. In this study, we com…

Multiple UAV cooperative path planning via neuro-dynamic programming

2004

In this paper, a team of n unmanned air-vehicles (UAVs) in cooperative path planning is given the task of reaching the assigned target while i) avoiding threat zones ii) synchronizing minimum time arrivals on the target, and iii) ensuring arrivals coming from different directions. We highlight three main contributions. First we develop a novel hybrid model and suit it to the problem at hand. Second, we design consensus protocols for the management of information. Third, we synthesize local predictive controllers through a distributed, scalable and suboptimal neuro-dynamic programming (NDP) algorithm.

Flexible pattern discovery with (extended) disjunctive logic programming

2005

The post-genomic era showed up a wide range of new challenging issues for the areas of knowledge discovery and intelligent information management. Among them, the discovery of complex pattern repetitions in string databases plays an important role, specifically in those contexts where even what are to be considered the interesting pattern classes is unknown. This paper provides a contribution in this precise setting, proposing a novel approach, based on disjunctive logic programming extended with several advanced features, for discovering interesting pattern classes from a given data set.

Errors and Complications in SQL Query Formulation

2018

SQL is taught in almost all university level database courses, yet SQL has received relatively little attention in educational research. In this study, we present a database management system independent categorization of SQL query errors that students make in an introductory database course. We base the categorization on previous literature, present a class of logical errors that has not been studied in detail, and review and complement these findings by analyzing over 33,000 SQL queries submitted by students. Our analysis verifies error findings presented in previous literature and reveals new types of errors, namely logical errors recurring in similar manners among different students. We…

Computing Platform for Virtual Economic Activities Index

2018

The authors enter three economic activity indices, which are calculated from the data in the virtual space on basis of Mobile Operator Call Description Records, Internet Log Files and News Portal audience textual comments and remarks analysis. The article provides the computing facility and the software specification for the Big Data computational platform. Indicates the need to comply this platform with strategy of data privacy requirements solutions and the visualization of results with data geographical mapping.

Context-sensitive text mining with fitness leveling Genetic Algorithm

2015

Contextual processing is a great challenge for information retrieval study - the most approved techniques include scanning content of HTML web pages, user supported metadata analysis, automatic inference grounded on knowledge base, or content-oriented digital documents analysis. We propose a meta-heuristic by making use of Genetic Algorithms for Contextual Search (GACS) built on genetic programming (GP) and custom fitness leveling function to optimize contextual queries in exact search that represents unstructured phrases generated by the user. Our findings show that the queries built with GACS can significantly optimize the retrieval process.

Experimental evaluation of hypertext access structures

2002

Transient hypertextual access structures (THASs) are temporary graphs formed automatically on the basis of the situation-dependent information needs of software engineers. The approach is implemented in the HyperSoft system, which is a hypertext-based software maintenance support tool. THASs highlight the relevant parts of the program and enable nonlinear browsing between them. The system also supports various graphical views whose elements are linked to the program text. This paper describes the effects of using these hypertextual structures in two separate experiments. The subjects of both experiments were computer science students (total N = 70). In both experiments, the subjects perform…