A Multi-Class Blockchain Services Framework for Communication Networks

The current World Wide Web service model treats all requests equivalently, both while being processed by servers and while being transmitted over the network. For some uses, such as Web prefetching or multiple priority schemes, different levels of service are desirable. This paper presents three simple, server-side, application-level mechanisms (limiting process pool size, lowering process priorities, limiting transmission rate) to provide two different levels of Web service (regular and low priority). We evaluated the performance of these mechanisms under combinations of two foreground workloads (light and heavy) and two levels of available network bandwidth (10 Mb/s and 100 Mb/s). Our experiments show that even with background traffic sufficient to saturate the network, foreground performance is reduced by at most 4–17%. Thus, our user-level mechanisms can effectively provide different service classes even in the absence of operating system and network support.

Connection management for QoS service on the Web

The study presented in this paper aims to quantify the impact of level of service on real time crash risks on freeways and to investigate the mechanisms of crash occurrences in different level of service. Using crash data and paired traffic data extracted from a northbound segment of the I-880 freeway in the United States, a conditional logit model is conducted to relate the crash risks to levels of service. It is found that LOS E had the greatest impact on crash occurrences on freeways, followed by LOS F and LOS D, and the crash risks associated with LOS B are not significantly different from those associated with LOS A. The random forest algorithm is further conducted to identify the contributing factors to crash occurrence in different LOS. The findings of random forest demonstrate that the mechanisms of crash occurrence are quite different across different levels of service. The vehicle platoon and abrupt change in vehicle speed contribute to the crash risks in LOS A and B. In LOS C or LOS D, lane changes have impacts on crash risks, and the high crash risks associated with LOS E are mainly caused by high traffic volumes and oscillating traffic conditions. The findings of this study suggests that different traffic management strategies should be developed in dynamic freeway traffic management systems based on the contributing factors to crash occurrences in different levels of service.

Introduction: Children and young people (CYP) with medical complexity, have high levels of healthcare needs and utilisation, representing 10% of patients attending children’s hospitals, and accounting for 60% of healthcare expenditure in the state of New South Wales (NSW), Australia. Furthermore, 30% of children in NSW live outside major cities and require enhanced local health solutions to manage healthcare needs, reduce travel and family disruptions and limit out-of-pocket expenses. The Rural Kids Guided Personalised Service (RuralKidsGPS) is a co-designed innovative integrated model of care coordination for CYP living with medical complexity, modelled on the successfully implemented and sustained KidsGPS program in tertiary children’s hospitals in Sydney. RuralKidsGPS is being implemented into four rural local health districts (LHDs) across NSW. This study explores early implementation barriers and enablers to inform contextual adaption and ensure scalability across diverse health settings. Methods: The implementation evaluation is informed by qualitative methods using semi-structured interviews and focus groups, with children and families, healthcare providers embedded researchers, and health service managers. Adopting an inductive approach underpinned by the Consolidated Framework for Implementation Research (CFIR), we identify implementation strategies, barriers and enablers influencing adoption, delivery, and sustainability of RuralKidsGPS. In this early phase of implementation evaluation (6-12 month after commencement) we have focused on implementation outcomes based on Proctor’s framework, including acceptability, appropriateness, adaptability, fidelity, and feasibility. Results: The interviews demonstrated the variations in setting and context across the LHDs and the adaption of RuralKidsGPS to meet local needs. Different levels of service demand, the time required for engagement with families from diverse socio-economic and cultural backgrounds and different levels of pre-existing service, and staff changes, contribute to the complexity of service implementation and delivery. All four LHDs share borders with jurisdictions outside of NSW, resulting in some children traveling across state or territory borders to access specialist health services. The complexities of sharing and gaining access to healthcare information across jurisdictions has impacted the timely delivery of care coordination and shared care plan development. RuralKidsGPS builds local healthcare capacity to manage CYP living with medical complexity but requires commitment and effort to build relationships with established local services and understanding of processes, and values, whilst conserving local resources. The perceived value and commitment to RuralKidsGPS by nurse care coordinators who leverage local knowledge and networks to deliver family-centred care, is a key enabler. Importantly, reciprocal support from health managers and health care professionals, and access to resources and networks is providing nurse coordinators the power to adapt and implement RuralKidsGPS. During this period, all LHDs were impacted by natural disasters (floods, bushfires) and COVID-19 creating barriers that required those implementing the RuralKidsGPS to flex and adapt. Conclusion: Early findings highlight the importance of adaptation to local contexts, the challenges and barriers and the resilience of the care coordinators implementing RuralKidsGPS. Care coordination enables families to navigate fragmented, complex health care systems, more efficiently and effectively. This research will inform the development of an implementation guide to support scaling and sustaining similar models of paediatric integrated care.

The paper investigates the probability of one of the most famous attacks - double spending attacks on the blockchain system, which are based on consensus mechanisms based on the proof of the work done using hash functions. Unlike previously known works describing the analytical expression for the probability of success of a double-spend attack, this paper proposes a model of independent players that is different from existing models. In our opinion, this model more adequately describes the processes that occur during the formation of a chain of blocks, but leads to other quantitative results. An expression is given that characterizes the probability of an attacker conducting a successful double-spend attack on a blockchain system depending on the number of confirmations used, as well as the hashrate by an honest network and the attacker. Quantitative results are presented, as well as a comparison of the results obtained with the most famous works in this area. Based on the results obtained, recommendations are given for determining the “safe” number of confirmations for successfully resisting a double spending attack on the blockchain system.

Wavelength division multiplexing/time division multiplexing (WDM/TDM) passive optical networks (PON) is being viewed as a promising solution for delivering multiple services and applications. The hybrid WDM / TDM PON uses the wavelength and bandwidth allocation strategy to control the distribution of the wavelength channels in the uplink direction, so that it can ensure the high bandwidth requirements of multiple Optical Network Units (ONUs) while improving the wavelength resource utilization. Through the investigation of the presented dynamic bandwidth allocation algorithms, these algorithms can't satisfy the requirements of different levels of service very well while adapting to the structural characteristics of mixed WDM / TDM PON system. This paper introduces a novel wavelength and bandwidth allocation algorithm to efficiently utilize the bandwidth and support QoS (Quality of Service) guarantees in WDM/TDM PON. Two priority based polling subcycles are introduced in order to increase system efficiency and improve system performance. The fixed priority polling subcycle and dynamic priority polling subcycle follow different principles to implement wavelength and bandwidth allocation according to the priority of different levels of service. A simulation was conducted to study the performance of the priority based polling in dynamic resource allocation algorithm in WDM/TDM PON. The results show that the performance of delay-sensitive services is greatly improved without degrading QoS guarantees for other services. Compared with the traditional dynamic bandwidth allocation algorithms, this algorithm can meet bandwidth needs of different priority traffic class, achieve low loss rate performance, and ensure real-time of high priority traffic class in terms of overall traffic on the network.

The widespread diffusion of distributed services, providing access to resources through the Net, has stressed the need of secure ways to authenticate users. The heterogeneity of resources leads to different authentication mechanisms implementations often requiring multiple log-on actions also in intra-domain multi-services scenario. The article presents a roadmap on authentication mechanisms implemented at different levels of services’ software structure.

A blockchain database containing files regarding transactions of cryptocurrency is sometime vulnerable to double spending attack. This type of attack pertains to a coin being spent more in more that one transaction in the network. This paper is motivated by a goal to create a blockchain that can withstand double spending attacks. This way, honest miners will be able to safely and securely exchange cryptocurrency. There currently lack valuable prevention methods in the network therefore we designed a novel countermeasure to combat double spending attacks on the blockchain system. We proposed the MSP (Multistage Secure Pool) framework in order to address the vulnerabilities on the blockchain. This was designed to handle both discrete and general issues that affect the overall security of the blockchain. Our evaluation using this application shows that there was a decrease in the amount of attacks propagating through the system based on our system's robustness and capabilities. We also present machine learning capabilities of the system in our study in order to enable a progressive aspect to the design. Providing our application with the ability to analyze data in order to recognize and classify distinct actions will enable for greater comprehension. An application that learns, updates and configures to meet specified defensive standards present key design features which enables for greater understanding and future analysis of the overall blockchain network.

We propose a novel pricing incentive mechanism based on multi-satges traffic classification methodology supporting load balancing and allocating network resource efficiently for QoS-enabled networks in this paper. We integrate the pricing with QoS routing and present a novel pricing incentive mechanism meeting the QoS requirements of different applications. This mechanism provides an equitable pricing incentive for applications according to their service requests. A novel multi-stages traffic classification methodology that brings together the benefits of port mapping, signature matching and flow character classification techniques is motivated by variety of network activities and their QoS requirements of traffic. We study the pricing and different levels of services in detail and integrate admission control scheme and load balancing in our framework. By theoretical analysis and extensive simulations, we prove its effectiveness in making traffic load balance and providing an incentive for users to utilize network resources to users’ satisfaction.

A given infrastructure system has different levels of service (LOS) for different users. To date, limited work has been done to combine these LOS to an asset level LOS. In addition, existing methods to determine LOS are based on the quantitative performance measures related to the capacity of the infrastructure systems. These methods neglect other qualitative factors, for example, neighborhood safety and appearance. This paper describes a proposed asset level of service (ALOS) determination methodology, which can be integrated with decision support systems (DSS) as a performance indicator. The proposed ALOS is a composite LOS for different users of the infrastructure system. Incorporation of ALOS with DSS will aid the municipalities in producing improved resource allocation plans in compliance with service standards, applicable codes, and regulations. In this paper, a framework of the development of ALOS in municipal infrastructure systems is presented. The analytical hierarchy process is used to model the ALOS. The developed framework is then applied to calculate the ALOS for the municipality/urban roads, to combine LOS for vehicle users, bicyclists, and pedestrians; accounting for qualitative factors, such as neighborhood safety and aesthetics.

1 - The Big Picture

The setup for the authors' problem consists of n servers that must complete a set of tasks. Each task can be handled only by a subset of the servers, requires a different level of service, and once assigned can not be re-assigned. They make the natural assumption that the level of service is known at arrival time, but that the duration of service is not. The on-line load balancing problem is to assign each task to an appropriate server in such a way that the maximum load on the servers is minimized. The authors derive matching upper and lower bounds for the competitive ratio of the on-line greedy algorithm for this problem, namely /sup (3n)2/3///sub 2/(1+o(1)), and derive a lower bound, Omega ( square root n), for any other deterministic or randomized on-line algorithm. >

Blockchain is a kind of distributed accounting system with the characteristics of decentralization, openness, transparency, non-tampering and de-trust. Recently, blockchain-based applications appear in various fields such as IoT, supply-chain, etc. A practical requirement of applying the Blockchain technology to the conventional supply-chain system is the trans-action synchronization between databases and the blockchain systems. This paper proposes a middleware that supports non-intrusive, efficient, fault-tolerant transaction data synchronization. The middleware is designed under three principles. The first is to divide the process of transaction synchronization into several independent phases. The second is to convert the representation of database transaction into an optimal form for blockchain, and transactions are packed and written into blockchain in a batch mode. The third is to guarantee the consistency between database and blockchain through failure recovery mechanism. Utilities like pipeline processing and transaction mapping built on this middleware achieve significant performance improvement. The peak TPS of Hyperledger Fabric reaches above 16000, which is more than 32 times of the direct submission method.

Transportation networks in parks and recreation areas provide travelers recreation opportunities and often support multiple transportation modes (e.g., hiking, walking, biking). In recreation areas, the quality of transportation service may be monitored and evaluated differently than in traditional transportation contexts. However, few studies have examined approaches for defining and monitoring the quality of transportation service and recreation experiences. This study applies traffic monitoring models to monitor (1) the quality of transportation service through the Levels of Service (LOS) framework and (2) travelers’ recreation experiences through the indicators and standards framework simultaneously on the Burlington Bike Path (BBP), a typical shared-use transportation recreation facility in Vermont. Results identify the temporal pattern of visitors use and the mode splits between cyclists and pedestrians. Moreover, study results show that the majority of travelers use the BBP for recreation or mixed purpose of recreation and commute. Study results build quantitative relationships between LOS and indicators and standards of quality that will help inform management of transportation in the context of recreation. The indicators and standards framework can help define the thresholds of acceptable levels of transportation service through the LOS framework. The relationships between LOS and the indicators and standards framework help build a robust and fully parameterized transportation planning and management framework for parks and recreation areas. Study results suggest quantitative guidelines that can be used to evaluate and monitor the quality of transportation performance for shared-use paths in parks and recreation areas.

M2I2tswTCM: A new efficient optimization marker algorithm to improve fairness bandwidth in DiffServ networks