This study builds upon the foundational research of Chidukwani et al. (2022, 2024) to critically examine and validate cybersecurity assertions made by small and medium-sized enterprises (SMEs). Through a mixed-method multiple case study design, the research employed a comprehensive methodology to gain firsthand insights into SME cybersecurity postures. Central to this study is the introduction of the Validated Cybersecurity Posture Assessment Framework (VCPAF), a novel multi-layered methodology tailored to the SME context. VCPAF integrates self-reported assessments, expert-led interviews, technical vulnerability scanning, artifact and documentation review, and a triangulated scoring and gap analysis. This holistic and iterative approach enables a more accurate and context-sensitive validation of cybersecurity practices, bridging the gap between perceived and actual security postures. Fieldwork included site visits, inspections, direct observations, and in-depth interviews with key personnel to validate initial survey responses from Chidukwani et al. (2024). Benchmarking against the NIST Cybersecurity Framework (CSF), the study revealed significant disparities between SMEs’ self-reported cybersecurity practices and evidence from expert assessments. SMEs consistently overstated their cybersecurity maturity, often conflating IT support with cybersecurity services. Overestimations were particularly notable across the NIST CSF’s five core functions: Identify, Protect, Detect, Respond, and Recover with critical weaknesses identified in asset management, patch management, network security, access control, monitoring, and incident response. Additionally, misunderstandings regarding IT provider responsibilities and regulatory obligations were found to exacerbate vulnerabilities. We conclude that self-reporting alone is insufficient for accurately assessing SME cybersecurity posture. To close the gap between perceived and actual security practices, independent validation and tailored frameworks are critical. We advocate for sector-specific adaptations of established standards, transparent service provider agreements, and mandatory employee training. Additionally, introducing an industry standardised terminology and taxonomy similar to those used in healthcare insurance would simplify service offerings, and improve SME understanding of cybersecurity responsibilities.

This study was prompted by the scarcity of focused quantitative research on the cybersecurity of SMBs. Our research aimed to understand the factors influencing SMBs' approach to cybersecurity, their level of threat awareness and the importance placed on cybersecurity. It also explored the extent to which NIST CSF practices are implemented by SMBs while also detecting and ranking the prevalent challenges faced by SMBs. Additionally, resources that SMBs turn to for help and guidance were also evaluated. While the survey-based study was on Western Australian SMBs, the results are of more general and wider interest. Our study found the lack of funds to be the biggest hindrance to cybersecurity, along with a lack of knowledge on where to start implementing good security practices. SMBs also lacked familiarity with relevant regulations and frameworks. The study highlights areas for improvement, such as access control mechanisms, individual user accounts, formalised policies and procedures, and dedicated budgets. SMBs heavily rely on Google search for cybersecurity information, emphasising the need for optimised search results from authoritative sources. IT service providers and informal networks also emerge as important sources of cybersecurity guidance, while local universities could assist SMBs but remain underutilised in this regard. Interestingly, factors such as organisational size, industry sector, and revenue level did not significantly impact SMBs' perception of vulnerability to cyber threats. However, further investigation is needed to evaluate the effectiveness of different IT service models for SMBs' cybersecurity needs. Overall, the research provides valuable insights into the specific gaps and challenges faced by SMBs in the cybersecurity domain, as well as their preferred methods of seeking and consuming cybersecurity assistance. The findings can guide the development of targeted strategies and policies to enhance the cybersecurity posture of SMBs.

Deep learning (DL) has achieved superior classification in many applications due to its capability of extracting features from the data. However, the success of DL comes with the tradeoff of possible overfitting. The bias towards the data it has seen during the training process leads to poor generalisation. One way of solving this issue is by having enough training data so that the classifier is invariant to many data patterns. In the literature, data augmentation has been used as a type of regularisation method to reduce the chance for the model to overfit. However, most of the relevant works focus on image, sound or text data. There is not much work on numerical data augmentation, although many real-world problems deal with numerical data. In this paper, we propose using a technique based on Fuzzy C-Means clustering and fuzzy membership grades. Fuzzy-related techniques are used to address the variance problem by generating new data items based on fuzzy numbers and each data item's belongings to different fuzzy clusters. This data augmentation technique is used to improve the generalisation of a Deep Neural Network that is suitable for numerical data. By combining the proposed fuzzy data augmentation technique with the Dropout regularisation technique, we manage to balance the classification model's bias-variance tradeoff. Our proposed technique is evaluated using four popular data sets and is shown to provide better regularisation and higher classification accuracy compared with popular regularisation approaches.

Street furniture such as bins, seats and bus shelters can become “smart” with the inclusion of wireless sensor nodes, which consist of environmental sensors, wireless modules, processors and microcontrollers. One of the most crucial challenges for smart street furniture is how to manage power consumption efficiently without affecting data freshness. In this work, we propose a novel Wireless Sensor Network (WSN)architecture for smart street furniture. Unlike existing WSNs which are based on a one-way communication model between wireless sensor nodes and the server, the proposed architecture employs a two-way communication model and a dynamic adaptation of the time interval of measurements to balance between power consumption and data updates. Our approach also provides a real-time low-power design for wireless sensor nodes which efficiently communicate the updated data instead of sending the same data on a regular basis. To the best of our knowledge, this is the first work in the relevant literature which extends the functionality of the wireless module in wireless sensor nodes to act not only as a station sending environmental data but also as soft Access Point (AP), sensing MAC addresses and WiFi signal strengths from surrounding WiFi-enabled devices. We have conducted experiments on the Murdoch University campus and our results show that our proposal improves lifetime of wireless sensor nodes up to 293% compared to static architectures similar to the ones that have been proposed in the literature. Moreover, network bandwidth is improved up to 38% without affecting data freshness. Finally, storage space for the database at the server is reduced up to 99%.

The explosive growth of multimedia applications renders the efficiency of network resource allocation a problem of major importance. The burstiness of video traffic, in particular, calls for traffic control solutions that will help prevent significant packet losses. Such losses can lead to unacceptable quality of service (QoS) and quality of experience (QoE) to users. In this paper, we focus on a large variety of H.264- and H.265-encoded video traces with different GoP patterns. Different versions of each trace, in low, medium, and high quality have been used in our study. We evaluate the accuracy of an existing video traffic prediction approach for the size of B-frames, and we propose a new Markovian model that predicts B-frames' sizes with significantly higher accuracy. B-frame size prediction can be used in order to reduce bandwidth requirements and smooth the encoded video stream, by selective B-frame dropping, when the model predicts larger upcoming B-frame traffic than the network can handle.

Studies on the composition and nature of Internet protocols are crucial for continued research and innovation. This study used three different methods to investigate the presence and level of support for various Internet protocols. Internet traffic entering and exiting a university network was passively captured, anonymised and analysed to test protocol usage. Active tests probed the Internet's most popular websites and experiments on the default behaviour of popular client, server and mobile operating systems were performed to reconcile the findings of the passive data collection. These results are valuable to research areas, such as those using emulations and simulations, where realism is dependent on the accuracy of the underlying assumptions about Internet traffic. Prior work is leveraged to explore changes and protocol adoption trends. This study shows that the majority of Internet traffic is now encrypted. There has also been an increase in large UDP frames, which we attribute to the Google QUIC protocol. Support for TCP options such as Selective Acknowledgements (SACK) and Maximum Segment Size (MSS) can now be assumed. Explicit Congestion Notification (ECN) usage is still marginal, yet active measurement shows that many servers will support the protocol if requested. Recent IETF standards such as Multipath TCP and TCP Fast Open have small but measurable levels of adoption.

Smart mobile devices have displaced personal computers in many daily applications such as internet browsing and email. However, for content creation, users still need to use a large display, keyboard and mouse. Many initiatives are currently working on enabling I/O functionality for content creation and peripheral access, and on preserving the grab-and-go experience where the mobile device is not tethered to the docking station but merely placed in proximity of it and the traffic is carried over Wi-Fi. Maintaining the Quality of Service (QoS) and Experience (QoE) of low-latency, high fidelity video (for example the desktop view of a smart device) when transmitted over a Wi-Fi link in heavily loaded environments has been proven problematic. In this work, we propose for the first time in the relevant literature to the best of our knowledge, a highly accurate video traffic model that is capable of predicting the volume of video traffic generated by an average user's computer during a day. Our modeling techniques are tested on real user-generated screen mirroring traffic from a large shared cube space similar to an enterprise environment, and can be easily used as source traffic generators in order to facilitate the study of H.264 transmission performance over wireless networks.

We investigate an affective saliency approach for speech emotion recognition of spoken dialogue utterances that estimates the amount of emotional information over time. The proposed saliency approach uses a regression model that combines features extracted from the acoustic signal and the posteriors of a segment-level classifier to obtain frame or segment-level ratings. The affective saliency model is trained using a minimum classification error (MCE) criterion that learns the weights by optimizing an objective loss function related to the classification error rate of the emotion recognition system. Affective saliency scores are then used to weight the contribution of frame-level posteriors and/or features to the speech emotion classification decision. The algorithm is evaluated for the task of anger detection on four call-center datasets for two languages, Greek and English, with good results.

We propose and evaluate the use of an affective-semantic model to expand the affective lexica of German, Greek, English, Spanish and Portuguese. Motivated by the assumption that semantic similarity implies affective similarity, we use word level semantic similarity scores as semantic features to estimate their corresponding affective scores. Various context-based semantic similarity metrics are investigated using contextual features that include both words and character n-grams. The model produces continuous affective ratings in three dimensions (valence, arousal and dominance) for all five languages, achieving consistent performance. We achieve classification accuracy (valence polarity task) between 85% and 91% for all five languages. For morphologically rich languages the proposed use of character n-grams is shown to improve performance.

The constant development of new multimedia applications, which are “greedy” in terms of bandwidth and Quality of Service (QoS) requirements, calls for new approaches to the traffic policing problem. This paper proposes, analyzes and presents an extensive performance evaluation of such a new approach, namely the activity-based video traffic policing. Using as a motivation recent work, which has shown that the classic traffic policing mechanisms provide unnecessarily strict policing for conforming but bursty video users, we propose five simple and efficient new mechanisms, which take into consideration and exploit video activity and the Group-of Pictures (GoP) pattern of the video traces. Contrary to the classic approach, our mechanisms do not use a token generator based on a fixed rate, but vary the token generation rate according to specific video activity-based algorithms. The results show significant improvement for conforming users, and reveal that dynamic traffic policing can provide much higher efficiency than the widely used static mechanisms. One of the new mechanisms, the Frame Size Aware Token Bucket, is shown to clearly outperform all other policing approaches for conforming users, and to provide comparable policing results with the classic mechanisms for non-conforming video users.

With more than 16 billion videos streamed on YouTube during last May and recent estimates by Cisco that mobile video traffic will increase 25-fold between 2011 and 2016, there is a pressing need to adequately serve large numbers of simultaneous online video transmissions. Network providers need to be able to guarantee the strict Quality-of-Service (QoS) requirements of real-time variable bit rate (VBR) video users, and a good statistical model for multiplexed video traffic can help significantly to evaluate and enhance network performance under various video loads. In this paper, we propose and evaluate a new hybrid video traffic model for MPEG-4 video. The genres of the videos considered in our study include lectures, cartoons, talk shows, action movies, sci-fi and sports. In the first part of our work, we build a Discrete Autoregressive model of order one (DAR(1)) and discuss its efficiency on capturing the behavior of real MPEG-4 video traces. We then proceed to build and evaluate a hybrid model which combines the DAR(1) model with a scene-change detection and classification algorithm, in order to provide us with higher modeling accuracy. The classification is performed based on the average number of bits generated during the scenes and the scene activity is modeled by a Markov chain where each state represents the degree of activity (high/low). Our extensive experimental evaluation study shows that the proposed hybrid method significantly improves the efficiency of pure DAR(1) schemes.

On behalf of the chairs and technical program committees of the different workshops, it is with great pleasure that we welcome you to Madrid for the 2013 IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks (WoWMoM). We are certain that you will enjoy the excellent quality of the technical program and the workshops, as well as the fine places and food of Madrid and surrounding cities.

Wireless networks face the challenge of being able to provide high Quality of Service (QoS) to users running different multimedia applications. As the number of applications continuously grows and multimedia users have widely different and contradictory QoS requirements, the task of the network designer in next generation wireless networks is further aggravated. Efficient Call Admission Control (CAC) and Traffic Policing (TP) mechanisms can significantly help towards improving user QoS. In this work, we focus on both the CAC and TP problems. We propose and evaluate new mechanisms which take into account the differentiated service contracts of wireless cellular video users and the Group-of-Pictures (GoP) patterns at the video traces. Both mechanisms are shown to outperform existing work in the relevant fields.

In recent work we have introduced and evaluated a fair and dynamic joint Call Admission Control (CAC) and Multiple Access Control (MAC) framework, for Geostationary Orbit (GEO) Satellite Systems, named Fair Predictive Resource Reservation Access (FPRRA). The framework was based on accurate videoconference and data traffic prediction, made decisions after taking into account the provider's revenue, and was shown to be highly efficient. In this paper we enhance FPRRA by talking into account the users' satisfaction for making scheduling decisions and we focus on its evaluation in the absence of accurate MPEG-4 and H.264 video traffic modeling. In addition, we discuss the efficiency of our proposed scheme in comparison to other efficient schemes from the literature.

It is our sincere pleasure to welcome you to the IEEE Workshop on Video Everywhere, taking place on June 25 in San Francisco, as part of the 13th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2012).

Wireless local area networks (WLANs) are now being used in places where access point (AP) power saving would be very desirable. Although this is not currently possible, modifications to the IEEE 802.11 protocol have recently been proposed which would permit this functionality. A difficult problem that arises is to maintain good client power saving when AP power saving is introduced. This is especially true when carrying multiple real-time traffic flows such as H.263 video, where the payload size varies randomly over short time periods. In this paper, we first present protocol modifications for power saving quality-of-service (QoS) enabled access points (PSQAP). We then focus on the transmission of bursty real-time H.263 video over a PSQAP. A variety of mechanisms are proposed for this purpose, which result in various tradeoffs between station and PSQAP power saving performance. Analytical models and simulation experiments are used to assess the performance of the video scheduling algorithms. The best overall performance is obtained using a mechanism that combines a novel variant of the power save multi-poll (PSMP) protocol with a scheduling mechanism based on a discrete autoregressive video prediction model.

Telemedicine traffic transmission over wireless cellular networks has gained in importance during the last few years. Due to the fact that this type of traffic carries critical information regarding the patients' condition, it is vitally important that multimedia telemedicine traffic has highest transmission priority in comparison to all other types of traffic in the cellular network. However, the need for expedited and correct transmission of telemedicine traffic calls for a guaranteed bandwidth to telemedicine users. This creates a tradeoff between the satisfaction of the very strict quality of service requirements of telemedicine traffic and the loss of the guaranteed bandwidth in the numerous cases when it is left unused, due to the infrequent nature of telemedicine traffic. In this paper, we propose a fair scheduling mechanism for telemedicine traffic transmission over wireless cellular networks. The mechanism achieves high channel bandwidth utilization while offering full priority to telemedicine traffic.

The subject of traffic policing for computer communication networks has been studied extensively in the literature. However, the constant development of new multimedia applications which are ldquogreedyrdquo in terms of bandwidth and Quality of Service requirements calls for new approaches to the traffic policing problem. In this work, we introduce a new video model for single H.263 videoconference sources and we use it in order to propose a new traffic policing approach for wireless videoconference traffic. We study well-known traffic policing mechanisms which still present interesting, unsolved problems when servicing video traffic and propose, to the best of our knowledge, for the first time in the relevant literature that the token generator is based on a traffic model and not on a fixed rate. The proposed approach shows significant improvement in the results obtained by all the traffic policing mechanisms, and hence, shows that dynamic traffic policing can provide much higher efficiency than the widely used static approach.

Due to the burstiness of video traffic, video modeling is very important in order to evaluate the performance of future wired and wireless networks. In this paper, we investigate the possibility of modeling H.264 videoconference traffic with well-known distributions. Our results regarding the behavior of single videoconference traces provide significant insight and help to build a Discrete Autoregressive (DAR(1)) model to capture the behavior of multiplexed H.264 videoconference movies from VBR coders.

User mobility, combined with the rapidly growing number of multimedia applications, form a challenging and yet unresolved problem for the development of call admission control schemes over next generation wireless cellular networks. In recent work we have modeled the behavior of H.264 video traces with the use of a discrete autoregressive (DAR(1)) model. Based on this model, we propose in this work a new efficient CAC scheme for H.264 video traffic over cellular networks, which uses precomputed traffic scenarios for its decision-making. Our scheme is shown, via an extensive simulation study, to clearly excel in comparison with well-known existing approaches, in terms of quality of service (QoS) provisioning to users receiving video traffic.

The constant development of new multimedia applications which are ldquogreedyrdquo in terms of bandwidth and quality of service requirements calls for new approaches to the traffic policing problem. In recent work we have modeled the behavior of multiplexed H.263 videoconference traces. Our results lead us to introduce, in this work, a new video traffic model for single H.263 videoconference sources and to propose a new traffic policing scheme for wireless videoconference traffic, based on the model. To the best of our knowledge, this is the first work in the relevant literature where the token generator is based on a traffic model, and not on a fixed rate.

IEEE 802.11 is now being used in many situations where access point (AP) power saving would be highly desirable. Unfortunately, this is not possible since the existing standard requires that APs remain active at all times. In this paper, we present a framework for a power saving quality-of-service (QoS) enabled access point (PSQAP), intended for use in low power infrastructure applications. The proposed scheme introduces infrastructure based power saving while preserving the QoS requirements for delay and loss intolerant real-time applications. Using an extensive simulation study we have evaluated the integrated framework, which consists of a proposed energy efficient media access control (MAC) protocol and an adaptive connection admission control (CAC) scheme. Our results show that the power consumption at PSQAPs can be significantly reduced without violating any of the QoS requirements for real-time traffic streams. The effect on power saving at the stations is also reasonable and can be controlled via protocol specific parameters.

In this work, we first introduce a new traffic model for medium quality MPEG-4 videoconference traffic and then proceed to use it in the implementation of a new call admission control scheme. Our scheme makes decisions on the acceptance/rejection of a new video call not only based on the predicted capacity that users will consume, but also on the possible revenue gained for the provider when degrading current users in order to accommodate new ones. Via an extensive simulation study our scheme is shown to provide excellent quality of service (QoS) to wireless videoconference users.

The subject of Call Admission Control (CAC) for wireless networks has been studied extensively in the literature. Another subject on which many researchers have focused their attention is that of video traffic modeling. However, user mobility, combined with the rapidly growing number of "greedy" multimedia applications, in terms of bandwidth and Quality of Service (QoS) requirements, form a challenging and yet unresolved problem for third and fourth-generation wireless networks. In recent work, we have built a Discrete Autoregressive (DAR (1)) model to capture the behavior of multiplexed H.263 videoconference movies from variable bit rate (VBR) coders. Based on this model, we propose in this work a new efficient CAC scheme for wireless cellular networks, which differs from the existing proposals in the literature in that it uses precomputed traffic scenarios combined with online simulation for its decision making. Our scheme is shown, via an extensive simulation study comparison and a conceptual comparison with well-known existing approaches, to clearly excel in terms of QoS provisioning to users receiving videoconference videoconference and Web traffic. To the best of our knowledge, this is the first work in the relevant literature where such an approach has been proposed.

User mobility, combined with the rapidly growing number of multimedia applications, form a challenging and yet unresolved problem for the development of call admission control schemes over next generation wireless cellular networks. In this work we propose a new efficient CAC scheme for MPEG-4 videoconference traffic over cellular networks, which uses precomputed traffic scenarios for its decision-making. Our scheme is shown, via an extensive simulation study, to clearly excel in comparison with well-known existing approaches, in terms of quality of service (QoS) provisioning to users receiving videoconference traffic.

In this paper we explore, via an extensive simulation study, the performance of a medium access control (MAC) protocol when integrating high-quality video, Web and MP3 data packet traffic over a wireless picocellular system of very high capacity, with errors and capture. Mobile terminals are considered to be high performance devices with extended storage capabilities which can act like cache memories streaming multimedia material. To the best of our knowledge, this is one of the first papers in the literature investigating the integration of H.264 video traffic with other types of traffic over wireless networks. Our results show that, despite the very bursty nature of the examined traffic and the burstiness of channel errors, the proposed scheme achieves very high throughput results while preserving the strict quality of service (QoS) requirements of each traffic type.

In this paper we explore, via an extensive simulation study, the performance of a Medium Access Control (MAC) protocol when integrating high-quality video, web and MP3 data packet traffic over a wireless picocellular system of very high capacity, with errors. Mobile terminals are considered to be high performance devices with extended storage capabilities which can act like cache memories streaming multimedia material. To the best of our knowledge, this is one of the first papers in the literature investigating the integration of H.264 video traffic with other types of traffic over wireless networks. Our results show that, despite the very bursty nature of the examined traffic and the burstiness of channel errors, the proposed scheme achieves very high throughput results while preserving the strict Quality of Service (QoS) requirements of each traffic type.

In recent work, we have introduced MI-MAC (Multimedia Integration Multiple Access Control), a new access control protocol for wireless cellular networks. MI-MAC was shown to be a good candidate for next generation wireless cellular networks, due to its superior performance in comparison to other (TDMA and WCDMA-based) protocols in the literature when integrating various types of multimedia traffic. In the present work we proceed further with the study of MI-MAC's efficiency, by evaluating its ability to efficiently integrate streams from latest technology video encoders with other types of packet traffic over noisy wireless networks. To the best of our knowledge, this is one of the first works in the literature to study the integration of H.264 streams with other types of multimedia traffic over wireless cellular networks.

User mobility, combined with the rapidly growing number of multimedia applications, form a challenging and yet unresolved problem for the development of call admission control schemes over next generation wireless cellular networks. In recent work the behavior of H.263 videoconference traces have been modeled with the use of a discrete autoregressive (DAR(Garawi et al., 2006)) model. Based on this model, a new efficient CAC scheme for videoconference traffic over cellular networks was proposed in this work, which uses precomputed traffic scenarios for its decision-making. The scheme is shown, via an extensive simulation study, to clearly excel in comparison with well-known existing approaches, in terms of quality of service (QoS) provisioning to users receiving videoconference traffic.

Both Call Admission Control (CAC) and efficient scheduling are of great importance in next generation wireless networks, which are expected to handle various types of highly emanding multimedia users. In this paper we present and evaluate an efficient new mechanism which combines Call Admission Control with bandwidth allocation in a high-speed downlink TDMA wireless channel with errors, by incorporating predictions of the wireless channel condition in its decision making.

Powerline communications (PLC) are currently being considered as an alternative for high-speed data communications and Internet access. With multiple outlets in almost every room, power lines are already the most pervasive network in the home or small office. This work presents a new medium access control (MAC) protocol for the "last mile" access PLC networks. Via an extensive simulation study, our protocol is compared to a well-known protocol from the literature and is shown to excel both in network utilization and in the average signaling delay required for the completion of the transmission request procedure.

Due to the burstiness of video traffic, video modeling is very important in order to evaluate the performance of future wired and wireless networks. In this paper we build a discrete autoregressive (DAR) model to capture the behavior of multiplexed H.263 videoconference movies from VBR coders. Our results show that the model provides great accuracy in its prediction of the behavior of the multiplexed sources.

We design and evaluate ,the performance of a new unified mechanism for downlink scheduling and call admission control (CAC) of multimedia traffic in a high-capacity TDMA wireless channel. In our scheme, the base station interacts with the call admission controller and incorporates predictions on the channel condition in its decision making. Our results show that, with the use of the "intelligent" scheduler-admission controller mechanism, system performance is significantly enhanced compared to two other schemes without prediction on the channel condition.

In this paper we explore, via an extensive simulation study, the performance of a new medium access control (MAC) protocol when integrating video and data packet traffic over a wireless picocellular system of very high capacity, with errors. Mobile terminals are considered to be high performance devices with extended storage capabilities which can act like cache memories streaming multimedia material. Our scheme achieves high aggregate channel throughput in all cases of traffic load, despite the very bursty nature of the examined traffic and the introduction of errors in the system.

An efficient medium access control (MAC) protocol is critical for the performance of a wireless sensor network (WSN), especially in terms of energy consumption. In this work we discuss the efficiency of S-MAC, a well-known MAC protocol for WSNs, and propose an improvement on the protocol. Via an extensive simulation study considering the cases of both simple and complicated topologies, the enhanced protocol is shown to outperform the original version of S-MAC in energy conservation

A medium access control (MAC) protocol for integrating voice, videoconferencing and email data packet traffic in a high capacity wireless channel while at the same time ensuring the high priority of video and voice is presented and investigated. By combining our past and new scheduling ideas with an idea recently introduced in the literature, the results of our formerly published work are significantly improved. We evaluate, via simulations and comparisons with other protocols in the recent literature, the performance of the protocol and we focus on the impact of different types and loads of data traffic on the system performance.

We explore, via an extensive simulation study, the performance of call admission control (CAC) and traffic policing mechanisms proposed for transmitting multiple-layered videoconference movies over a wireless channel of high capacity, depending on the user's needs and requests. We focus both on MPEG-4 and H.263 coded movies, and, in the latter case, our scheme achieves high aggregate channel throughput, while preserving the very strict quality of service (QoS) requirements of the video traffic.

A medium access control (MAC) protocol for wireless multimedia communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice, H.263 variable bit rate (VBR) video and bursty e-mail data packet traffic over a wireless picocellular system of high capacity. Our scheme achieves high aggregate channel throughput in all examined cases of traffic loads, while satisfying the quality of service (QoS) requirements of each traffic type.

In this paper we explore, via an extensive simulation study, the performance of a new medium access control (MAC) protocol when integrating voice, video and E-mail data packet traffic over a wireless channel of high capacity, with errors. We evaluate the voice and video packet dropping probabilities and the average E-mail data message delays. Our scheme achieves high aggregate channel throughput in all cases of traffic load, despite the presence of noise in the system and the very restraining video dropping probability limit.

A new medium access control (MAC) protocol for mobile wireless communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice, MPEG-4 video and e-mail data packet traffic over a wireless channel of high capacity. Our scheme achieves high aggregate channel throughput in all cases of traffic load, while preserving the quality of service (QoS) requirements of each traffic type.

A new medium access control (MAC) protocol for mobile wireless communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice, video and data packet traffic over a wireless channel of high capacity. Depending on the number of video users admitted into the system, our protocol varies: (a) the request bandwidth dedicated to resolving the voice users contention, and (b) the probability with which the base station grants information slots to voice users, in order to preserve full priority for video traffic. We evaluate the voice and video packet dropping probabilities for various voice and video load conditions, and the average data message delays. As proven by the comparison with a previously introduced efficient MAC scheme (DPRMA), when integrating voice and video traffic our scheme obtains higher voice capacity and aggregate channel throughput. When integrating all three traffic types, our scheme achieves high aggregate channel throughput in all cases of traffic load.

A new multiple access control (MAC) protocol for mobile wireless communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice and data traffic over two wireless channels, one of medium capacity (referring mostly to outdoor microcellular environments) and one of high capacity (referring to an indoor microcellular environment). We evaluate the voice packet dropping probability and access delay, as well as the data packet access and data message transmission delays for various voice and data load conditions. Our protocol achieves near-optimal voice sources multiplexing results along with most satisfactory voice and data performance and quality of service (QoS) requirements servicing.