Search results for "Computer network"
showing 10 items of 1634 documents
Expansive Voronoi Tree: A Motion Planner for Assembly Sequence Planning
2021
One major challenge in Assembly Sequence Planning (ASP) for complex real-world CAD-scenarios is to find an appropriate disassembly path for each assembled part. Complex real-world scenes are characterized by a large installation space. There each part has many different possible disassembly paths that differ in length and clearance. However, due to tight packing in the installation space, these paths can contain narrow passages. Therefore a motion planner is needed that is able to globally search for a reasonable path and to locally overcome narrow passages. Moreover, since motion planning requests are executed in the ASP context over and over again for many parts, both for those that can b…
On solving separable block tridiagonal linear systems using a GPU implementation of radix-4 PSCR method
2018
Partial solution variant of the cyclic reduction (PSCR) method is a direct solver that can be applied to certain types of separable block tridiagonal linear systems. Such linear systems arise, e.g., from the Poisson and the Helmholtz equations discretized with bilinear finite-elements. Furthermore, the separability of the linear system entails that the discretization domain has to be rectangular and the discretization mesh orthogonal. A generalized graphics processing unit (GPU) implementation of the PSCR method is presented. The numerical results indicate up to 24-fold speedups when compared to an equivalent CPU implementation that utilizes a single CPU core. Attained floating point perfor…
Bidirectional labeling for solving vehicle routing and truck driver scheduling problems
2020
Abstract This paper studies the vehicle routing and truck driver scheduling problem where routes and schedules must comply with hours of service regulations for truck drivers. It presents a backward labeling method for generating feasible schedules and shows how the labels generated with the backward method can be combined with labels generated by a forward labeling method. The bidirectional labeling is embedded into a branch-and-price-and-cut approach and evaluated for hours of service regulations in the United States and the European Union. Computational experiments show that the resulting bidirectional branch-and-price-and-cut approach is significantly faster than unidirectional counterp…
IoT-MAAC: Multiple Attribute Access Control for IoT environments
2020
Access Control is an important security service that should be considered in IoT environments in order to offer reliable IoT services. Access control in IoT environments concerns not only the access of IoT users to IoT services and objects, but also the access of IoT objects to IoT gateways. In this paper, we specify an access control mechanism that considers the access of IoT objects to IoT gateways in order to enhance the reliability of IoT data provided by the IoT objects. Our proposed access control mechanism, called IoT-MAAC (Multi Attribute Access Control), allows retrieving requested data from the most reliable and secured IoT objects among the available objects in the IoT environmen…
A cultural comparison study of smartphone adoption in Uzbekistan, South Korea and Turkey
2017
Smartphone popularity is increasing due to the technological advances that mean manufacturers can make more sophisticated devices, and telecommunication companies can provide better connections. Gartner reported that 403 million smartphones were sold in the fourth quarter of 2015, a 9.7% increase over the same period in 2014. It is a common perception that users tend to utilise advanced technology to increase productivity. However, there are studies indicating quite opposite or alternatively slow rates of adoption. To avoid this, companies invest in studying consumer behaviour. The purpose of the study is to examine the effects of drivers and cultural differences on smartphone acceptance in…
Specification and Implementation of Multicast Congestion Control Stair Protocol: Use Case with Multimedia Ubiquitous Networks
2008
Ubiquitous and efficient multicast data delivery service is essential to the success of large-scale group communication applications. In this framework, congestion control through ubiquitous networks is a hot topic for multicast real time protocols. In this paper, authors present specification and implementation of simulate TCP's AIMD with rate-based (STAIR), a multicast congestion control mechanism. Authors have enhanced this approach because they have modeled it using Unified Modeling Language with real time extensions (UML-RT) as a formal specification tool. More to the point point, they introduce a multimedia ubiquitous network which they have used as a reference model to promote their …
Software Requirements for Ubiquitous Ad Hoc Mobile Networks: An Example of a Bluetooth Application
2009
In contrast with the simple and elegant concept of global computing, also called ubiquitous computing - where daily life objects get now computing capacity and interact among them to provide a wide range of services to users - a major difficulty is arising with the software engineering process to develop applications for these devices. This article discusses the additional parameters that should be taken into account when designing and developing software for ubiquitous devices in ad-hoc networks. In these networks the mobility of the devices could increase the complexity of the requirements to be considered. As a case study, we present a Bluetooth application that has been developed to ful…
A Simulation Based Analysis of an Multi Objective Diffusive Load Balancing Algorithm
2018
In this paper, we presented a further development of our research on developing an optimal software-hardware mapping framework. We used the Petri Net model of the complete hardware and software High Performance Computing (HPC) system running a Computational Fluid Dynamics (CFD) application, to simulate the behaviour of the proposed diffusive two level multi-objective load-balancing algorithm. We developed an meta-heuristic algorithm for generating an approximation of the Pareto-optimal set to be used as reference. The simulations showed the advantages of this algorithm over other diffusive algorithms: reduced computational and communication overhead and robustness due to low dependence on u…
Cruise passengers' experiences in a Mediterranean port of call. The case study of Valencia
2014
Most cruise tourism studies have been restricted to one geographical region, the Caribbean, to a single cruise line, and to onboard experiences. Despite their relevance there has been little research on the Mediterranean region, on specific ports of call and on off-board experience. Furthermore, in the cruise context, there have been no studies on the role of culture in consumer behavior. Hoping to help fill this void, this research analyzed the influence of cruise passengers' image of a Mediterranean port of call on visit satisfaction and future behavioral intentions, and the moderating role of culture in causal relationships among these constructs. Data were collected in the port of Valen…
Social Interaction in YouTube Text-Based Polylogues: A Study of Coherence
2012
Since YouTube was launched, its emblematic video-sharing facility has attracted considerable attention as a social networking system of cultural production. In addition to vlogging, YouTube offers a text facility through which YouTubers share and negotiate opinions. However, research into the latter is scarce, especially within language-based disciplines (Androutsopoulos & Beiβwenger 2009; Zelenkauskaite & Herring 2008). This article contributes to addressing this imbalance by focusing on YouTube text-based ‘conversation’ (Herring 2010a). Specifically, it examines coherence in a corpus of YouTube postings in Spanish. Although coherence has been the object of much academic debate in other fo…