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The Internet of things (IoT) extends the Internet space by allowing smart things to sense and/or interact with the physical environment and communicate with other physical objects (or things) around us. In IoT, sensors, actuators, smart devices, cameras, protocols, and cloud services are used to support many intelligent applications such as environmental monitoring, traffic monitoring, remote monitoring of patients, security surveillance, and smart home automation. To optimize the usage of an IoT network, certain challenges must be addressed such as energy constraints, scalability, reliability, heterogeneity, security, privacy, routing, quality of service (QoS), and congestion. To avoid congestion in IoT, efficient load balancing (LB) is needed for distributing traffic loads among different routes. To this end, this survey presents the IoT architectures and the networking paradigms (i.e., edge–fog–cloud paradigms) adopted in these architectures. Then, it analyzes and compares previous related surveys on LB in the IoT. It reviews and classifies dynamic LB techniques in the IoT for cloud and edge/fog networks. Lastly, it presents some lessons learned and open research issues. [ABSTRACT FROM AUTHOR]

Purpose – The aim of this work is to evaluate Greek newspaper websites using clustering and a number of criteria obtained from the Alexa search engine. Furthermore, a recommendation approach is proposed for matching Greek online newspapers with the profiles of potential readers. The paper presents the implementation and validation of a recommender tool that suggests to a user (based on age, education and income) an optional Greek newspaper's website to read. Design/methodology/approach – A total of 25 newspaper websites were selected from the Greek information bank http://edoellada.gr. After investigating these websites one by one, this number was decreased to 16 websites due to their printing prevention, cessation or no coverage by Alexa. Findings – Based on data obtained from Alexa, the Naftemporiki newspaper has the highest traffic rank and the Eleftherotypia newspaper the largest number of links among others. The Macedonia newspaper has the largest number of foreign users. The results of the study also show that most newspaper websites' visitors come from the UK. The expectation-maximisation (EM) clustering algorithm classifies the 16 websites into two groups based on some common characteristics. Research limitations/implications – The proposed recommendation approach is generic because it can be applied as a recommendation solution on various types of website, such as educational or commercial. However, slight adjustments are needed depending on the nature of recommending websites. Practical implications – A website administrator of an online newspaper can adapt the newspaper's features such as content and layout according to the prevailing user profile of the online newspaper. For example, a website administrator of an online newspaper whose dominant user education is "no-college" should enable the writing style of this newspaper in a more naive way. The administrator can also add advertisements that are more suitable to readers aged between 35 and 55 years, if the most frequent age of users of this online newspaper is between 35 and 55. Originality/value – The results of this research will be important not only to administrators of Greek newspaper websites but also to anyone with a need to increase the usage of a website. [ABSTRACT FROM AUTHOR]

This article proposes a quantitative evaluation framework of all the dimensions provided by hotel websites. The proposed framework evaluates the richness of specific and comprehensive information. A proposed conceptual model that describes the hotel websites' features is used in order to summarize the data and consider how sound websites are in terms of technology and management. The model combines various dimensions (i.e., information attributes, website design attributes, reservation engine facilities, payment, provided services attributes, provided information attributes, quality of content, language support, website operating attributes, website structure, navigation, and search facilities). The proposed evaluation method is based on the websites evaluation by users/guests, hotel managers, and IT professionals, while it uses principal components analysis (PCA) to estimate the performance score from users/guests, hotel managers, and IT professionals as well the overall score of a website. Using this framework, we determine how each data dimension impacts on each performance indicator as well as on the overall performance. We applied our method and evaluated 30 chain hotel websites operating in Greece, and found interesting insights for the hotel chain industry in Greece. [ABSTRACT FROM PUBLISHER]

Purpose - This paper aims to provide an overview of representative multimedia applications in the cultural heritage sector, as well as research results on quality of service (QoS) mechanisms in internet protocol (IP) networks that support such applications. Design/methodology/approach - The paper's approach is a literature review. Findings - Cultural heritage multimedia applications require greater bandwidth capacity, especially where multiple users share the connections. For such applications, scalability and reliability of quality of service depend on packet-level QoS mechanisms operating in a full end-to-end basis. Research limitations/implications - The paper provides a foundation for future research directions in the professional communication context. For instance, the QoS mechanisms in possible network infrastructures could be used to explore effective multimedia data dissemination across cultural heritage institutions. Practical implications - The paper provides an overview of which technologies/mechanisms are being used most broadly and which might provide the most potential for cultural heritage institutions managers considering experimenting in the multimedia communications area. Originality/value - QoS mechanisms that support multimedia applications in the cultural heritage sector need to become well known by cultural heritage institutions managers and professional associations in the fields of libraries, museums and archives. This paper provides a useful overview of the topic. [ABSTRACT FROM AUTHOR]

An open-source management system of Web-based teaching interventions is presented that can be used in general for science curriculum courses and especially for computer science courses. The proposed solution is called System of Teaching Intelligent Interventions (STII) and facilitates the authoring, deployment, and evaluation of Web-based metaphors. This paper discusses the use of metaphors for assisting students to comprehend the substance of cognitive concepts and their basic background. STII has been applied in a particular educational scenario during the learning process of 228 students attending the course "computer applications." The presentation of results from a pilot evaluation of two metaphors demonstrates the usefulness of the system. The evaluation focuses on the impact of the two metaphors on student learning, and on detecting potential correlations between metaphors and students' groups. STII evaluation conclusions strongly support that multimedia metaphors can be used as an alternative instructional tool to assist students in confronting their cognitive constraints and developing functional understanding of curriculum courses. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one by Lilia Cheniti-Belcadhi et al on Semantic Web, one by Dimitris Stavrinoudis et al on the behavior of the users of an e-learning system, and one by Akbar Hussain et al on a Computer Algebra System (CAS) application.

Nowadays highly-skilled attackers can find the vulnerabilities of many networked applications. Meanwhile, the risk of a data breach increases dramatically as a software or application vulnerability always remains without a patch. By exploiting such vulnerability (called zero-day), hackers gain entry to the target network and can steal sensitive data. It is challenging to detect zero-day with traditional defenses because signature information in zero-day attacks is unknown. Consequently, a novel security solution is required that will discover zero-day attacks and estimate the severity of identified zero-day vulnerability. In this paper, we propose a framework that constitutes an integrated approach for detection and prioritization (based on likelihood) of zero-day attacks. The proposed framework follows a probabilistic approach for identification of the zero-day attack path and further to rank the severity of identified zero-day vulnerability. It is a hybrid detection-based technique that detects unknown flaws present in the network that are not detected yet. To evaluate the performance of the proposed framework, we adopted it in the network environment of Vikram university campus, India. The framework is very promising as experimental results showed detection rate of 96% for zero-day attacks with 0.3% false positive rate. [ABSTRACT FROM AUTHOR]

Stream Control Transmission Protocol (SCTP) exploits multiple network interfaces to provide multi-streaming and data chunk ordering in a stream. An extended feature of SCTP, i.e., Concurrent Multi-path Transfer (CMT), bids concurrent data transmission in a multi-path data transfer environment and guarantees bandwidth aggregation, load sharing, robustness, and reliability. In such an environment, the paths usually have distinct characteristics (i.e., delay, Packet Loss Rate (PLR), and bandwidth). Thus, data chunks are received out-of-ordered at the destination. As a result, CMT causes excessive receiver buffer blocking and unnecessary congestion window (cwnd) reductions. Also, during the selection of the retransmission destination path (to resend a lost data chunk), CMT does not take into account vital Quality of Service (QoS) parameters such as the PLR of a path under consideration. This paper introduces a new Delay-Based Concurrent Multi-path Transfer (DB-CMT) approach that transmits data on multiple paths according to their delay. In this scheme, we present a Delay-Based Data chunk Scheduling Policy (DB-DSP), a Retransmission Path Selection Policy (RTX-CL), and a new Delay-Based Fast Retransmission Policy (DB-FRP). The simulation results show that the DB-CMT’s RTX-CL policy performs better than the well-known RTX-CWND and RTX-LOSSRATE retransmission schemes. Also, the overall performance of DB-CMT witnesses improved throughput, fewer timeouts, and reduced File Transfer Time (FTT) performances. [ABSTRACT FROM AUTHOR]

• We developed a Delay-based Adaptive Congestion Control TCP variant (DACC). • DACC has an initialization method that obtains an optimal initial value for the congestion window. • It has a queueing-delay variation-based scheme that contemplates the contribution of all contention traffic flows. • It has improved performance in goodput, throughput, file transfer time, and fairness. Delay-based congestion control policies of the Transmission Control Protocol (TCP) mainly use the Round-Trip-Time (RTT) and bottleneck queue size to detect congestion. However, these policies identify congestion by only taking into account the contribution of their own data flow. Thus, the congestion identification in these policies fails to be completely accurate. Moreover, these policies experience many packet losses resulting in retransmissions, which can further reduce channel utilization. This article proposes a queuing delay variation-based adaptive congestion control TCP variant, called Delay-based Adaptive Congestion Control (DACC), that considers the presence of background flows. DACC quickly adapts to the current network conditions and adjusts the transmission rate accordingly. The simulation results exemplify the significance of DACC as it yields better outcomes in terms of goodput, Packet Loss Ratio (PLR), inter-protocol fairness, intra-protocol fairness, and fast file transfers. [Display omitted] [ABSTRACT FROM AUTHOR]

In mobile ad hoc networks (MANETs), the IEEE 802.11 CSMA/CA is deployed as the primary medium access control (MAC) layer protocol to schedule the access to the wireless medium. The IEEE 802.11 standard was designed with the assumption that nodes would never deviate from the protocol. However, MANET nodes may purposefully show misbehavior at the MAC layer to obtain more bandwidth or degrade the network performance and disrupt the network services. This paper reviews and classifies the most important strategies generating MAC layer misbehavior based on their objectives and operating principles. Then, it examines some of the recent proposed solutions and mechanisms for detecting and preventing MAC layer misbehavior. A comparison of the studied solutions is carried out using a set of critical evaluation metrics. Finally, the paper concludes with a brief summary of key ideas and a general direction that can provide a basis for future work. [ABSTRACT FROM AUTHOR]

In the IEEE 802.11 standard, network nodes experiencing collisions on the shared medium need a mechanism that can prevent collisions and improve the throughput. Furthermore, a backoff mechanism is used that uniformly selects a random period of time from the contention window (cw) that is dynamically controlled by the Binary Exponential Backoff (BEB) algorithm. Prior research has proved that the BEB scheme suffers from a fairness problem and low throughput, especially under high traffic load. In this paper, we present a new backoff control mechanism that is used with the IEEE 802.11 distributed coordination function (DCF). In particular, we propose a dynamic, deterministic contention window control (DDCWC) scheme, in which the backoff range is divided into several small backoff sub-ranges. In the proposed scheme, several network levels are introduced, based on an introduced channel state vector that keeps network history. After successful transmissions and collisions, network nodes change their cw based on their network levels. Our extensive simulation studies show that the DDCWC scheme outperforms four other well-known schemes: Multiplicative Increase and Linear Decrease, Double Increment Double Decrement, Exponential Increase Exponential Decrease, and Linear/Multiplicative Increase and Linear Decrease. Moreover, the proposed scheme, compared with the IEEE 802.11 DCF, gives 30.77% improvement in packet delivery ratio, 31.76% in delay, and 30.81% in throughput. [ABSTRACT FROM AUTHOR]