Perform Data Dissemination Research Articles

Efficient & Reliable Algorithm for Route Selection in A Wireless Sensor Networks

Abstract: The routing schemes in Wireless Sensor Network (WSN) systems are performed among the groups of different clusters. The node works for data aggregation from the source nodes and they also perform data dissemination and network management and events sensing and information collecting in the neighbourhood. Many clustering topologies have been proposed in recent years to localize the route within the cluster itself. In this work, it has been reviewed and compared these topologies to find out the network mechanism which is easier to manage and scalable for getting high quality response with respect to dynamics of the environment.

Introducing a handshake for data dissemination using rateless codes in vehicular ad hoc networks

AbstractData dissemination in vehicular networks is a notable problem because of the highly dynamic characteristics of these networks and the instability state of channels. Protocols that perform data dissemination based on MAC structure cannot provide reliable communication between vehicles. Protocols that use coding for data dissemination are reliable; however, they are either confronted with collision or not suitable for short time communication. In some situation, the node cooperation is low. In this paper, we extend the idea of data dissemination using rateless codes, DDRC. We introduce a proper handshake for data dissemination using rateless codes, HDDRC. This handshake is based on accelerated movement mathematical calculations. It calculates communication time duration between two members of handshake and sets a proper NAV (Network Allocation Vector). During NAV time, the channel is reserved and only handshake's members are allowed to communicate with each other. Therefore, handshake eliminates collision problem in the receiver node. Simulation results show that the protocol performance is improved by the vehicle's acceleration, which results in increasing the number of cooperating nodes. Comparing the two existing algorithms, DDRC and CORP, HDDRC causes the vehicles to receive messages in a shorter period of time and shorter traveled length of roads. Therefore, HDDRC improves the network performance. Copyright © 2015 John Wiley & Sons, Ltd.

Adaptive Backbone Based Cooperative Caching in Mobile Ad hoc Networks

Existing cooperative caching algorithms for mobile ad hoc networks face serious challenges due to message overhead and scalability issues. To solve these issues, we propose an adaptive virtual backbone based cooperative caching that uses a connective dominating set (CDS) to find the desired location of cached data. Message overhead in cooperative caching is mainly due to cache lookup process used for cooperative caching. The idea in this scheme is to reduce the number of nodes involved in cache look up process, by constructing a virtual backbone adaptive to the dynamic topology in mobile ad hoc networks. The proposed algorithm is decentralized and the nodes in the CDS perform data dissemination and discovery. Simulation results show that the message overhead created by the proposed cooperative caching technique is very less compared to other approaches. Moreover, due to the CDS based cache discovery we applied in this work, the proposed cooperative caching has the potential to increase the cache hit ratio and reduce average delay.

The importance of a supportive environment in clinical audit: a pilot study of doctors' engagement with the NHS National PET-CT audit programme.

The NHS National PET-CT Audit Programme was launched in 2008 as part of a national NHS programme to widen patient access to PET-computed tomography (CT) imaging in England. However, to implement clinical audit effectively, healthcare professionals need to be fully engaged with the process. The purpose of the pilot study was to identify and explore the different factors that influence doctors' engagement with the National NHS PET-CT Audit Programme. A single embedded case study was undertaken, which centred on the NHS National PET-CT Audit Programme. Seven theoretical propositions drawn from a review of the literature were tested and their influence evaluated. A purposeful sample of 13 semistructured interviews with consultant doctors was taken from different hospitals over a 6-month period. The data were analysed using directed thematic content analysis, with the themes compared against the study's propositions. Doctors' perspectives of clinical audit changed in response to the way in which the audit was implemented. The main barriers to engagement were the lack of a common vision and poor communication, which contributed to poor interprofessional relationships and a perceived culture of blame. In contrast, factors that facilitated engagement centred on the adoption of a more supportive and collaborative approach, which in turn facilitated higher levels of trust between professionals. The dissemination of performance data was found to be a key influencing factor. The study makes use of a unique data set and to the best of our knowledge is one of the first studies to document how the dissemination of doctors' performance data positively influences engagement with clinical audit in England. In addition, the study also shows how, contrary to some studies in the literature, clinical audit can reduce professional anxiety by providing a validation of professional competence. The study supports the premise that clinical audit will be fully embraced by doctors only if they are sufficiently involved in the process so as to be able to redefine and clarify its purpose and meaning. The preliminary findings of this pilot study provide the theoretical underpinning for a national survey into reporter perspectives of the National PET-CT Audit Programme.

DDDRC: decentralised data dissemination in VANET using raptor codes

The design of data dissemination protocol has been a great challenge due to the highly dynamic and unreliable wireless channel in vehicular ad hoc networks (VANET). In literature, several interesting solutions are proposed to perform data dissemination for this environment. But these solutions either use architectures requiring centralised coordination or global network knowledge or large intermediate buffers. In this paper, we propose a decentralised technique that overcomes above requirements and provides reliable and scalable communication in both dense and sparse traffic for VANET. Random walks are used in the proposed technique to disseminate data from one vehicle to other vehicles in the network. We use raptor codes to provide low decoding complexity and more scalability for data dissemination. Simulation results demonstrate that the proposed technique has better fault tolerance with lower complexity than general random-walk-based dissemination process and more scalability as compared to the other protocols.

모바일 P2P 네트워크에서 효율적인 콘텐츠 검색을 위한 데이터 배포 기법

모바일 P2P 네트워크를 위해 제안된 데이터 배포 기법들은 프로파일과 일치하는 콘텐츠 검색 성능은 매우 뛰어나지만 프로파일과 일치하지 않는 콘텐츠 검색의 경우 질의 처리를 위한 추가적인 비용이 발생하기 때문에 프로파일과 일치하지 않는 콘텐츠 검색 성능 향상에 대한 추가적인 고려가 필요하다. 이러한 문제를 해결하기 위해 본 논문에서는 모바일 P2P 환경에서 효율적인 콘텐츠 검색을 위한 새로운 데이터 배포 기법을 제안한다. 제안하는 기법에서는 타임스탬프 메시지를 사용함으로써 이전 통신 경험 여부를 판단하고 이에 따른 데이터 배포를 수행한다. 또한, 제한된 메모리에 배포된 데이터를 효율적으로 저장하기 위해 랭킹 기법을 제안한다. 제안하는 랭킹 기법은 프로파일 일치여부 뿐만 아니라 주변의 배포 범위, 데이터를 배포해준 피어와의 연결성을 고려함으로서 차후의 질의 배포를 감소시킬 수 있다. In the existing data dissemination methods for mobile P2P networks, the search performance of content that matches the peer profile is very excellent. However, in the search for content that does not match the their profile, additional consideration about case that contents does not match the profile is needed because costs for the query processing will be incurred. To solve these problems, we propose a new data dissemination method for efficient contents search in mobile P2P networks. In the proposed method, peers determine whether they experienced communications by using a timestamp message and then perform data dissemination. We also propose a ranking algorithm to efficiently store dissemination data in a limited memory. The proposed ranking method can reduce query messages by considering the profile matches, the distribution range, and the connectivity to the data distribution peer.

Performance Measurement in Health Care: History, Challenges and Prospects

A confluence of forces has resulted in massive changes to the collection and use of performance data in the UK health system over the past 25 years. Performance measurement offers major potential benefits for clinical professionals, managers, regulators, politicians, researchers, patients and citizens. However, uncritical reliance on performance data can lead to a number of unintended and adverse consequences. The National Health Service has pioneered the assembly and dissemination of performance data from the early 1980s. This article summarizes the history of performance measurement in the NHS, assesses its effectiveness to date, discusses the major challenges in deploying performance measures, and highlights priorities for policy-makers.

Performance Measurement in Health Care: History, Challenges and Prospects

A confluence of forces has resulted in massive changes to the collection and use of performance data in the UK health system over the past 25 years. Performance measurement offers major potential benefits for clinical professionals, managers, regulators, politicians, researchers, patients and citizens. However, uncritical reliance on performance data can lead to a number of unintended and adverse consequences. The National Health Service has pioneered the assembly and dissemination of performance data from the early 1980s. This article summarizes the history of performance measurement in the NHS, assesses its effectiveness to date, discusses the major challenges in deploying performance measures, and highlights priorities for policy-makers.