Search results for "Travel"

Regular and singular pulse and front solutions and possible isochronous behavior in the Extended-Reduced Ostrovsky Equation: Phase-plane, multi-infin…

2016

In this paper we employ three recent analytical approaches to investigate several classes of traveling wave solutions of the so-called extended-reduced Ostrovsky Equation (exROE). A recent extension of phase-plane analysis is first employed to show the existence of breaking kink wave solutions and smooth periodic wave (compacton) solutions. Next, smooth traveling waves are derived using a recent technique to derive convergent multi-infinite series solutions for the homoclinic orbits of the traveling-wave equations for the exROE equation. These correspond to pulse solutions respectively of the original PDEs. We perform many numerical tests in different parameter regime to pinpoint real saddl…

2020

Background Physical activity trackers (PATs) such as apps and wearable devices (eg, sports watches, heart rate monitors) are increasingly being used by young adolescents. Despite the potential of PATs to help monitor and improve moderate-to-vigorous physical activity (MVPA) behaviors, there is a lack of research that confirms an association between PAT ownership or use and physical activity behaviors at the population level. Objective The purpose of this study was to examine the ownership and use of PATs in youth and their associations with physical activity behaviors, including daily MVPA, sports club membership, and active travel, in 2 nationally representative samples of young adolescen…

Ingvar the Far-Travelled: between the Byzantium and Caucasus. A Maritime Approach to Discussion

2019

The Journey to the East of the Viking Ingvar the Far-Traveled is one of the events that fit into the history of medieval relations of the Scandinavians with the world of Byzantium. It was a fateful expedition taking place between 1036 and 1041, and to this day it is a source of many controversies and speculations of researchers. The findings of the present paper suggest that the journey did not necessarily proceed to the lands of the Saracens or Byzantium but may have been part of the game played by Constantinople with its ally Tmutarkan, which opposed Jaroslav the Wise, these events unfolding in the north-eastern waters of the Black Sea.

Between the Darkness of Barbarism and the Light of Civilization: British Images of the Finn in the Late Eighteenth Century

2014

This article aims to show that it was the British travellers (Coxe, Tooke, Clarke,et al.) to Finland in the late eighteenth century who discovered Finland for theBritish reading public. As they distinguished the Finns as a separate ‘race’ fromthe Russians, the Swedes, and the Lapps, they contributed to the proto-racialistimage of them that would become popular in the nineteenth century. BecauseSweden had become an important maritime trading partner (in iron ore, tar, andtimber) to the British, its eastern part, Finland, also became an interesting countryto visit en route from Stockholm to Saint Petersburg (or from Saint Petersburgto Stockholm). The travellers were astonished to realize that…

Pero Tafur and Bertradon de la Broquière in Constantinople: The Ceremonial Image of Mary of Trabzond and the Diplomatic Meetings around the Council o…

2019

After the fall of Constantinople (1453), Pero Tafur and Bertrandon de La Broquière make known their works, which are two of the most important travel books written in Europe during the fifteenth century. Both travellers had known, between fifteen and twenty years before, the emperor of Greece, John VIII Palaiologos, Pope Eugene IV and other protagonists of the councils of Basel (1431-1434) and Ferrara-Florence (1438-1439), which decreed the union between the Roman and Greek churches. The travellers were, thus, witnesses, but also informants and active diplomats for the attempts of religious and political union, which Pope Pius II tried to revive after the fall of Constantinople. Tafur and L…

Do the mobile-rich get richer? Internet use, travelling and social differentiations in Finland

2014

This article investigates the daily travelling practices that are related to mobile-only, fixed-only and combined mobile/fixed use of the Internet, and the social differentiations that are related to these three ways of accessing the Internet. Survey data ( N = 612) collected from Finland in 2011 are analysed. The article shows that mobile-only Internet use is not associated with particularly diverse or frequent daily travelling practices, whereas combined mobile/fixed use is. Mobile-only Internet users are, in fact, in a relatively disadvantaged position – compared with other users, they are more typically unemployed and their household income is lower. The mobility of Internet access as …

The Steiner Traveling Salesman Problem and its extensions

2019

Abstract This paper considers the Steiner Traveling Salesman Problem, an extension of the classical Traveling Salesman Problem on an incomplete graph where not all vertices have demand. Some extensions including several depots or location decisions are introduced, modeled and solved. A compact integer linear programming formulation is proposed for each problem, where the routes are represented with two-index decision variables, and parity conditions are modeled using cocircuit inequalities. Exact branch-and-cut algorithms are developed for all formulations. Computational results obtained confirm the good performance of the algorithms. Instances with up to 500 vertices are solved optimally.

NP-completeness of the hamming salesman problem

1985

It is shown that the traveling salesman problem, where cities are bit strings with Hamming distances, is NP-complete.

The computational complexity of the relative robust shortest path problem with interval data

2004

Abstract The paper deals with the relative robust shortest path problem in a directed arc weighted graph, where arc lengths are specified as intervals containing possible realizations of arc lengths. The complexity status of this problem has been unknown in the literature. We show that the problem is NP -hard.

A class of label-correcting methods for the K shortest paths problem

2001

In this paper we deal with the problem of finding the first K shortest paths from a single origin node to all other nodes of a directed graph. In particular, we define the necessary and sufficient conditions for a set of distance label vectors, on the basis of which we propose a class of methods which can be viewed as an extension of the generic label-correcting method for solving the classical single-origin all-destinations shortest path problem. The data structure used is characterized by a set of K lists of candidate nodes, and the proposed methods differ in the strategy used to select the node to be extracted at each iteration. The computational results show that: 1. some label-correct…