Search results for "Computer network"

Endpoint Admission Control over Assured Forwarding PHBs and Its Performance over RED Implementations

2001

The Assured Forwarding Per Hop Behavior (AF PHB) has been devised by the IETF Differentiated Services (DiffServ) working group to provide drop level differentiation. The intent of AF is to support services with different loss requirements, but with no strict delay and jitter guarantees. Another suggested use of AF is to provide differentiated support for traffic conforming to an edge conditioning/policing scheme with respect to nonconforming traffic. Scope of this paper is twofold. First, we show that, quite surprisingly, a standard AF PHB class is semantically capable of supporting per flow admission control. This is obtained by adopting the AF PHB as core routers forwarding mechanism in c…

PCP: An End-to end Measurement Based Call Admission Control for Real-Time Services Over IP Networks

2000

Distributed end-to-end measurement based connection admission control mechanisms have been recently proposed. The goal of these schemes is to provide tight QoScon trol on a per connection basis by means of measurements taken by the edge nodes and priority based forwarding procedure at internal nodes. Since the additional flows handling procedures are implemented at the border routers and the forwarding mechanisms are for flows aggregates only, the approach is fully scalable and compatible with the IETF Differentiated Service proposal. The aim of this paper is to propose specific schemes and to investigate the advantages and limits of the approach by analyzing the basic mechanisms and evalua…

Automated Synthesis of Application-layer Connectors from Automata-based Specifications

2019

Abstract Ubiquitous and Pervasive Computing, and the Internet of Things, promote dynamic interaction among heterogeneous systems. To achieve this vision, interoperability among heterogeneous systems represents a key enabler, and mediators are often built to solve protocol mismatches. Many approaches propose the synthesis of mediators. Unfortunately, a rigorous characterization of the concept of interoperability is still lacking, hence making hard to assess their applicability and soundness. In this paper, we provide a framework for the synthesis of mediators that allows us to: (i) characterize the conditions for the mediator existence and correctness; and (ii) establish the applicability bo…

High performance hardware correlation coefficient assessment using programmable logic for ECG signals

2003

Abstract Correlation coefficient is frequently used to obtain cardiac rhythm by peak estimation and appreciate differences in the signal compared to a pattern. This work focuses on the description of a real-time correlation assessment procedure. Applied to electrocardiogram (ECG) signals, a new correlation value is obtained every new sample and pulse detection information is provided. The ECG pattern is internally stored and can be changed when desired. This procedure is useful in Systems on Chip implementation and can be applied to design compact ECG monitoring systems consisting on a system on chip where programmable logic offloads the main processor. A Xilinx FPGA device has been used fo…

‘Tour me onshore’: understanding cruise tourists’ evaluation of shore excursions through text mining

2018

ABSTRACTThe aim of this paper is to shed light on the elements underlying cruise tourists’ evaluation of shore excursions, approaching them as an interaction of expressive and instrumental components.To fulfil the aim of the investigation, a thematic content analysis of 1296 online reviews was conducted using the text-mining software Leximancer. The results of the study revealed that cruise visitors with different overall satisfaction with their guided tour focus the narrative of their opinion on different tour attributes. Thus, the dominant themes of the cruise passengers delighted with their tour included the performance of the tour guide, the arrangement of the tour, as well as the cruis…

Tracing the Cultural Background of Lone-Wolf Terrorism

2021

The end of the Cold War, as well as the collapse of the Soviet Union, posed new greater challenges and risks for the “Global North.” Terrorism—doubtless—seems to be one of them. Over the recent years, and particularly after 9/11, terrorists changed the focus of their attacks. While classic terrorism targeted important persons such as politicians, chief police officers, or celebrities, modern terrorism planned attacks on leisure-spots spaces, tourist destinations, and lay-persons. This is particularly troublesome for policymakers (who are in charge of orchestrating all-pervading models to preserve homeland security) and for field-workers who are seriously punished when they are in contact wi…

2020

Abstract Information technology (IT) engagement is defined as a need to spend more time using IT. Practice-based examples show that IT engagement can have adverse effects in organizations. Although users can potentially get more work done through IT engagement, observations show that the users might jeopardize their well-being and hamper their work performance. We aimed to investigate this complexity in the research on IT engagement by examining its potential antecedents and outcomes in organizations. Considering the potentially mixed outcomes, we developed a model to examine the effects of IT engagement on personal productivity and strain. We also aimed to explain the antecedents of IT eng…

Consumers' perceptions of mobile banking continuous usage in Finland and South Africa

2015

This study examines continuous usage behaviour related to mobile banking (m-banking) among consumers living in Finland (FI) and South Africa (ZA). The study investigates three post-adoption behavioural consequences - namely, trust, satisfaction and word of mouth. Using purposeful sampling techniques, we found that trust plays a significant role in promoting continuous usage of m-banking. In general, the respondents reported high levels of trust in m-banking technology and were satisfied with the m-banking application and services. In addition, convenience, user friendliness and speed emerged as the main sub-topics related to satisfaction. In most cases, the convenience of using m-banking do…

Cyber Security and the Internet of Things: Vulnerabilities, Threats, Intruders and Attacks

2015

Internet of Things (IoT) devices are rapidly becoming ubiquitous while IoT services are becoming pervasive. Their success has not gone unnoticed and the number of threats and attacks against IoT devices and services are on the increase as well. Cyber-attacks are not new to IoT, but as IoT will be deeply interwoven in our lives and societies, it is becoming necessary to step up and take cyber defense seriously. Hence, there is a real need to secure IoT, which has consequently resulted in a need to comprehensively understand the threats and attacks on IoT infrastructure. This paper is an attempt to classify threat types, besides analyze and characterize intruders and attacks facing IoT device…

Criminal networks analysis in missing data scenarios through graph distances.

2021

Data collected in criminal investigations may suffer from: (i) incompleteness, due to the covert nature of criminal organisations; (ii) incorrectness, caused by either unintentional data collection errors and intentional deception by criminals; (iii) inconsistency, when the same information is collected into law enforcement databases multiple times, or in different formats. In this paper we analyse nine real criminal networks of different nature (i.e., Mafia networks, criminal street gangs and terrorist organizations) in order to quantify the impact of incomplete data and to determine which network type is most affected by it. The networks are firstly pruned following two specific methods: …