Search results for "ACCESS CONTROL"
showing 10 items of 79 documents
An Experimental Testbed and Methodology for Characterizing IEEE 802.11 Network Cards
2006
It has been observed that IEEE 802.11 commercial cards produced by different vendors show a different behavior in terms of perceived throughput or access delay. Performance differences are evident both when the cards contend alone to the channel, and when heterogeneous cards contend together. Since the performance misalignment does not disappear by averaging the environmental factors (such as propagation conditions, laptop models, traffic generators, etc), it is evident that the well known throughput-fairness property of the DCF protocol is not guaranteed in actual networks. In this paper we propose a methodological approach devised to experimentally characterize the IEEE 802.11 commercial …
Opportunistic Synchronization for Improving IEEE 802.15.4 MAC Performance in Chain Topologies
2010
The most effective solution for energy saving in low-rate wireless sensor networks is maintaining each node in a doze state as long as possible. In order to guarantee network connectivity, the intervals at which the network sensors are turned on and off have to be coordinated. Therefore, synchronization is a very critical function for sensor networks. In this paper, we analyze the IEEE 802.15.4 MAC performance in sensor networks deployed in a chain topology. For this topology, critical inefficiencies can arise in case of multi-hop packet deliveries. We evaluate the impact of different synchronization schemes on the network performance, both in terms of network throughput and in terms of ene…
A Patient-Centric Attribute Based Access Control Scheme for Secure Sharing of Personal Health Records Using Cloud Computing
2016
Personal health records (PHR) are an emerging health information exchange model, which facilitates PHR owners to efficiently share their private health data among a variety of users including healthcare professionals as well as family and friends. PHRs are usually outsourced and stored in third-party cloud platforms which relieves PHR owners from the burden of managing their PHR data while achieving better availability of health data. However, outsourcing private health data raises significant privacy concerns because there is a higher risk of leaking health information to unauthorized parties. To ensure PHR owners' control of their outsourced PHR data, attribute based encryption (ABE) mech…
Security, Reliability and Usability of mHealth Environments
2015
Mobile technologies confer mobility and autonomy on patients with the advantage of access to home care and health care services on demand. However, these benefits impose challenges to the future health care services. For instance, computation capacity of a conventional smartphone provides applications and services with sufficient power of calculation and automation to assist in daily life activities and medical purposes. Combined with a user-friendly interface, mobile technologies can be an easy and efficient manner to help people who are in a condition of cognitive deterioration or have a chronic disease which demands a close connection to near family members and/or to health care services.
Decentralized Lightweight Group Key Management for Dynamic Access Control in IoT Environments
2020
Rapid growth of Internet of Things (IoT) devices dealing with sensitive data has led to the emergence of new access control technologies in order to maintain this data safe from unauthorized use. In particular, a dynamic IoT environment, characterized by a high signaling overhead caused by subscribers' mobility, presents a significant concern to ensure secure data distribution to legitimate subscribers. Hence, for such dynamic environments, group key management (GKM) represents the fundamental mechanism for managing the dissemination of keys for access control and secure data distribution. However, existing access control schemes based on GKM and dedicated to IoT are mainly based on ce…
A space-division time-division multiple access scheme for high throughput provisioning in WLANs
2005
Directional antennas may dramatically increase the capacity of a Wireless LAN by allowing several stations to simultaneously communicate. Since deployment of directive/smart antennas on the customer's terminals is awkward (for technological, cost, robustness, and convenience reasons) it is of interest to deploy advanced antenna solutions only at the Access Point. When omnidirectional transmissions are used at the Mobile Stations, the asynchronous nature of the 802.11 MAC handshake structurally limits the possibility to exploit spatial reuse. Significant throughput enhancements can be achieved only at the expense of redesigning (part of) the 802.11 MAC protocol: mainly a form of synchronizat…
Attribute based access control scheme with controlled access delegation for collaborative E-health environments
2017
Abstract Modern electronic healthcare (e-health) settings constitute collaborative environments with complex access requirements. Thus, there is a need for sophisticated fine-grained access control mechanisms to cater these access demands and thereby experience the full potential of e-health systems. In order to realize a flexible access control scheme, integrating access delegation is of paramount importance. However, access delegation has to be enforced in a controlled manner so that it will not jeopardize the security of the system. In this paper, we addressed this issue through proposing an attribute based access control scheme integrated with controlled access delegation capabilities. …
Revisit of RTS/CTS Exchange in High-Speed IEEE 802.11 Networks
2005
IEEE 802.11 medium access control (MAC), called distributed coordination function (DCF), provides two different access modes, namely, 2-way (basic access) and 4-way (RTS/CTS) handshaking. The 4-way handshaking has been introduced in order to combat the hidden terminal phenomenon. It has been also proved that such a mechanism can be beneficial even in the absence of hidden terminals, because of the collision time reduction. We analyze the effectiveness of the RTS/CTS access mode, in current 802.11b and 802.11a networks. Since the rates employed for control frame transmissions can be much lower than the rate employed for data frames, the assumption on the basis of the 4-way handshaking introd…
Towards Risk-aware Access Control Framework for Healthcare Information Sharing
2018
Blockchain Based Delegatable Access Control Scheme for a Collaborative E-Health Environment
2018
Modern electronic healthcare (e-health) settings constitute collaborative environments requiring sophisticated fine-grained access control mechanisms to cater their access demands. Access delegatability is quite crucial to realize fine-grained, flexible access control schemes compatible with such environments. In this paper, we addressed this issue through proposing an attribute based access control scheme integrated with controlled access delegation capabilities suitable for a multi-domain e-health environment. We have utilized the blockchain technology to manage attribute assignments, delegations as well as revocations. The scheme enables delegations in a controlled manner without jeopard…