The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
José Rufino - One of the best experts on this subject based on the ideXlab platform.
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analysing and reducing network Inaccessibility in ieee 802 15 4 wireless communications
Local Computer Networks, 2013Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Network Inaccessibility is a temporal issue derived from the presence of faults affecting the communication services provided by the medium access control (MAC) sublayer. The occurrence of network Inaccessibility represents temporary “communication blackouts”, which prevent communications to be performed and may imply disruptions of network operation, therefore compromising the dependability and timeliness of communications. This paper uses an analytical model accounting for network Inaccessibility periods in wireless sensor and actuator networks, presenting the IEEE 802.15.4 standard as a case study. The analytical model is then used to derive a set of simple, yet quite effective policies to reduce the durations of the periods of network Inaccessibility. The effectiveness of these policies can be evaluated using a tool based on the analytical model, which is being integrated in the NS-2 simulator for validation. Reducing network Inaccessibility is a crucial step to enable the use of wireless networking technologies in real-time settings.
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LCN - Analysing and reducing network Inaccessibility in IEEE 802.15.4 wireless communications
38th Annual IEEE Conference on Local Computer Networks, 2013Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Network Inaccessibility is a temporal issue derived from the presence of faults affecting the communication services provided by the medium access control (MAC) sublayer. The occurrence of network Inaccessibility represents temporary “communication blackouts”, which prevent communications to be performed and may imply disruptions of network operation, therefore compromising the dependability and timeliness of communications. This paper uses an analytical model accounting for network Inaccessibility periods in wireless sensor and actuator networks, presenting the IEEE 802.15.4 standard as a case study. The analytical model is then used to derive a set of simple, yet quite effective policies to reduce the durations of the periods of network Inaccessibility. The effectiveness of these policies can be evaluated using a tool based on the analytical model, which is being integrated in the NS-2 simulator for validation. Reducing network Inaccessibility is a crucial step to enable the use of wireless networking technologies in real-time settings.
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characterization of Inaccessibility in wireless networks a case study on ieee 802 15 4 standard
International Embedded Systems Symposium, 2009Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Wireless technology has been seen as the communication technology of the future. One of many challenges is the support for predictability and time-bounded communications over this technology. In this way, the control of temporary partitions, called Inaccessibility, is of fundamental importance. For this reason, this paper makes a characterization of Inaccessibility in wireless networks and describes an exhaustive study about it on IEEE 802.15.4 wireless standard. The knowledge of Inaccessibility incidents and their duration is a first step to define means to control network partitioning and therefore to form a basis for supporting real-time communications over wireless technology.
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IESS - Characterization of Inaccessibility in Wireless Networks: A Case Study on IEEE 802.15.4 Standard
IFIP Advances in Information and Communication Technology, 2009Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Wireless technology has been seen as the communication technology of the future. One of many challenges is the support for predictability and time-bounded communications over this technology. In this way, the control of temporary partitions, called Inaccessibility, is of fundamental importance. For this reason, this paper makes a characterization of Inaccessibility in wireless networks and describes an exhaustive study about it on IEEE 802.15.4 wireless standard. The knowledge of Inaccessibility incidents and their duration is a first step to define means to control network partitioning and therefore to form a basis for supporting real-time communications over wireless technology.
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integrating Inaccessibility control and timer management in canely
Emerging Technologies and Factory Automation, 2006Co-Authors: José Rufino, Paulo Veríssimo, C. Almeida, Guilherme ArrozAbstract:The CAN Enhanced Layer (CANELy) is a CAN-based infrastructure capable of extremely reliable communication. This paper describes the mechanisms and the techniques used in CANELy to enforce system correctness in the time-domain despite the occurrence of network errors (Inaccessibility). The paper discusses how to integrate in the existing CANELy machinery, the control of Inaccessibility and the management of timers, at several levels of the system. In particular, application and low-level protocol layers are addressed. In addition, a relevant set of parameters are available for system monitoring, allowing the validation/enforcement of the system model.
Jeferson L. R. Souza - One of the best experts on this subject based on the ideXlab platform.
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analysing and reducing network Inaccessibility in ieee 802 15 4 wireless communications
Local Computer Networks, 2013Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Network Inaccessibility is a temporal issue derived from the presence of faults affecting the communication services provided by the medium access control (MAC) sublayer. The occurrence of network Inaccessibility represents temporary “communication blackouts”, which prevent communications to be performed and may imply disruptions of network operation, therefore compromising the dependability and timeliness of communications. This paper uses an analytical model accounting for network Inaccessibility periods in wireless sensor and actuator networks, presenting the IEEE 802.15.4 standard as a case study. The analytical model is then used to derive a set of simple, yet quite effective policies to reduce the durations of the periods of network Inaccessibility. The effectiveness of these policies can be evaluated using a tool based on the analytical model, which is being integrated in the NS-2 simulator for validation. Reducing network Inaccessibility is a crucial step to enable the use of wireless networking technologies in real-time settings.
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LCN - Analysing and reducing network Inaccessibility in IEEE 802.15.4 wireless communications
38th Annual IEEE Conference on Local Computer Networks, 2013Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Network Inaccessibility is a temporal issue derived from the presence of faults affecting the communication services provided by the medium access control (MAC) sublayer. The occurrence of network Inaccessibility represents temporary “communication blackouts”, which prevent communications to be performed and may imply disruptions of network operation, therefore compromising the dependability and timeliness of communications. This paper uses an analytical model accounting for network Inaccessibility periods in wireless sensor and actuator networks, presenting the IEEE 802.15.4 standard as a case study. The analytical model is then used to derive a set of simple, yet quite effective policies to reduce the durations of the periods of network Inaccessibility. The effectiveness of these policies can be evaluated using a tool based on the analytical model, which is being integrated in the NS-2 simulator for validation. Reducing network Inaccessibility is a crucial step to enable the use of wireless networking technologies in real-time settings.
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characterization of Inaccessibility in wireless networks a case study on ieee 802 15 4 standard
International Embedded Systems Symposium, 2009Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Wireless technology has been seen as the communication technology of the future. One of many challenges is the support for predictability and time-bounded communications over this technology. In this way, the control of temporary partitions, called Inaccessibility, is of fundamental importance. For this reason, this paper makes a characterization of Inaccessibility in wireless networks and describes an exhaustive study about it on IEEE 802.15.4 wireless standard. The knowledge of Inaccessibility incidents and their duration is a first step to define means to control network partitioning and therefore to form a basis for supporting real-time communications over wireless technology.
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IESS - Characterization of Inaccessibility in Wireless Networks: A Case Study on IEEE 802.15.4 Standard
IFIP Advances in Information and Communication Technology, 2009Co-Authors: Jeferson L. R. Souza, José RufinoAbstract:Wireless technology has been seen as the communication technology of the future. One of many challenges is the support for predictability and time-bounded communications over this technology. In this way, the control of temporary partitions, called Inaccessibility, is of fundamental importance. For this reason, this paper makes a characterization of Inaccessibility in wireless networks and describes an exhaustive study about it on IEEE 802.15.4 wireless standard. The knowledge of Inaccessibility incidents and their duration is a first step to define means to control network partitioning and therefore to form a basis for supporting real-time communications over wireless technology.
Akwasi Adjei Gyimah - One of the best experts on this subject based on the ideXlab platform.
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why does Inaccessibility widely exist in healthcare in ghana understanding the reasons from past to present
Journal of Public Health, 2020Co-Authors: Prince Peprah, Hayford Isaac Budu, Emmanuel Mawuli Abalo, Williams Agyemangduah, Akwasi Adjei GyimahAbstract:The topic of access, or improving access, to healthcare services is a noteworthy matter, regardless of where you live. In Ghana, however, especially in rural areas, it is a critical issue worthy of investigation. Thus, we set out with the aim of exploring the specific reasons for healthcare Inaccessibility in Ghana. Telephone interviews were conducted with 15 health directors in the Eastern, Central, and Ashanti regions of Ghana. A thematic analytical framework was used to analyze the data, which were then presented based on an a posteriori, inductive-reduction approach. Six major reasons were identified: inherent Inaccessibility initiated by the colonial system of administration, where essential healthcare facilities were concentrated in the capitals; economic reforms of past governments, especially the Structural Adjustment Programme which introduced the user fee system; transportation issues; urban-biased health policy implementation; the financial leakage/inefficiency/corruption that characterize interventions toward accessibility promotion; and other socio-cultural and religious beliefs that certain groups and tribes adhere to. The authors therefore argue that there is no one main cause of healthcare Inaccessibility in Ghana, but rather a confluence of issues is responsible, ranging from historical antecedents to current happenings. It is, therefore, imperative for stakeholders in the health sector to take into consideration the factors identified by the present study, in order to guide the design and implementation of policies toward improving healthcare accessibility.
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Why does Inaccessibility widely exist in healthcare in Ghana? Understanding the reasons from past to present
Journal of Public Health, 2019Co-Authors: Prince Peprah, Hayford Isaac Budu, Emmanuel Mawuli Abalo, Williams Agyemang-duah, Akwasi Adjei GyimahAbstract:AimThe topic of access, or improving access, to healthcare services is a noteworthy matter, regardless of where you live. In Ghana, however, especially in rural areas, it is a critical issue worthy of investigation. Thus, we set out with the aim of exploring the specific reasons for healthcare Inaccessibility in Ghana.Subject and methodsTelephone interviews were conducted with 15 health directors in the Eastern, Central, and Ashanti regions of Ghana. A thematic analytical framework was used to analyze the data, which were then presented based on an a posteriori, inductive-reduction approach.FindingsSix major reasons were identified: inherent Inaccessibility initiated by the colonial system of administration, where essential healthcare facilities were concentrated in the capitals; economic reforms of past governments, especially the Structural Adjustment Programme which introduced the user fee system; transportation issues; urban-biased health policy implementation; the financial leakage/inefficiency/corruption that characterize interventions toward accessibility promotion; and other socio-cultural and religious beliefs that certain groups and tribes adhere to.ConclusionThe authors therefore argue that there is no one main cause of healthcare Inaccessibility in Ghana, but rather a confluence of issues is responsible, ranging from historical antecedents to current happenings. It is, therefore, imperative for stakeholders in the health sector to take into consideration the factors identified by the present study, in order to guide the design and implementation of policies toward improving healthcare accessibility.
Maria Kiskowski - One of the best experts on this subject based on the ideXlab platform.
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vaccination strategies to control ebola epidemics in the context of variable household Inaccessibility levels
PLOS Neglected Tropical Diseases, 2019Co-Authors: Gerardo Chowell, Amna Tariq, Maria KiskowskiAbstract:Despite a very effective vaccine, active conflict and community distrust during the ongoing DRC Ebola epidemic are undermining control efforts, including a ring vaccination strategy that requires the prompt immunization of close contacts of infected individuals. However, in April 2019, it was reported 20% or more of close contacts cannot be reached or refuse vaccination, and it is predicted that the ring vaccination strategy would not be effective with such a high level of Inaccessibility. The vaccination strategy is now incorporating a “third ring” community-level vaccination that targets members of communities even if they are not known contacts of Ebola cases. To assess the impact of vaccination strategies for controlling Ebola epidemics in the context of variable levels of community accessibility, we employed an individual-level stochastic transmission model that incorporates four sources of heterogeneity: a proportion of the population is inaccessible for contact tracing and vaccination due to lack of confidence in interventions or geographic Inaccessibility, two levels of population mixing resembling household and community transmission, two types of vaccine doses with different time periods until immunity, and transmission rates that depend on spatial distance. Our results indicate that a ring vaccination strategy alone would not be effective for containing the epidemic in the context of significant delays to vaccinating contacts even for low levels of household Inaccessibility and affirm the positive impact of a supplemental community vaccination strategy. Our key results are that as levels of Inaccessibility increase, there is a qualitative change in the effectiveness of the vaccination strategy. For higher levels of vaccine access, the probability that the epidemic will end steadily increases over time, even if probabilities are lower than they would be otherwise with full community participation. For levels of vaccine access that are too low, however, the vaccination strategies are not expected to be successful in ending the epidemic even though they help lower incidence levels, which saves lives, and makes the epidemic easier to contain and reduces spread to other communities. This qualitative change occurs for both types of vaccination strategies: ring vaccination is effective for containing an outbreak until the levels of Inaccessibility exceeds approximately 10% in the context of significant delays to vaccinating contacts, a combined ring and community vaccination strategy is effective until the levels of Inaccessibility exceeds approximately 50%. More broadly, our results underscore the need to enhance community engagement to public health interventions in order to enhance the effectiveness of control interventions to ensure outbreak containment.
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Vaccination strategies to control Ebola epidemics in the context of variable household Inaccessibility levels
arXiv: Quantitative Methods, 2019Co-Authors: Gerardo Chowell, Amna Tariq, Maria KiskowskiAbstract:In the context of the ongoing Ebola epidemic in DRC, active conflict and community distrust are undermining control efforts, including vaccination strategies. In this paper, we employed an individual-level stochastic structured transmission model to assess the impact of vaccination strategies on epidemic control in the context of variable levels of household Inaccessibility. We found that a ring vaccination strategy of close contacts would not be effective for containing the epidemic in the context of significant delays to vaccinating contacts even for low levels of household Inaccessibility and evaluate the impact of a supplemental community vaccination strategy. For lower levels of Inaccessibility, the probability of epidemic containment increases over time. For higher levels of Inaccessibility, even the combined ring and community vaccination strategies are not expected to contain the epidemic even though they help lower incidence levels, which saves lives, makes the epidemic easier to contain and reduces spread to other communities. We found that ring vaccination is effective for containing an outbreak until the levels of Inaccessibility exceeds approximately 10%, a combined ring and community vaccination strategy is effective until the levels of Inaccessibility exceeds approximately 50%. Our findings underscore the need to enhance community engagement to public health interventions.
Dominik Aronsky - One of the best experts on this subject based on the ideXlab platform.
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the prevalence and Inaccessibility of internet references in the biomedical literature at the time of publication
Journal of the American Medical Informatics Association, 2007Co-Authors: Dominik Aronsky, Sina Madani, Randy J Carnevale, Stephany N Duda, Michael FeyderAbstract:Objectives: To determine the prevalence and Inaccessibility of Internet references in the bibliography of biomedical publications when first released in PubMed®. Methods: During a one-month observational study period (Feb 21 to Mar 21, 2006) the Internet citations from a 20% random sample of all forthcoming publications released in PubMed during the previous day were identified. Attempts to access the referenced Internet citations were completed within one day and inaccessible Internet citations were recorded. Results: The study included 4,699 publications from 844 different journals. Among the 141,845 references there were 840 (0.6%) Internet citations. One or more Internet references were cited in 403 (8.6%) articles. From the 840 Internet references, 11.9% were already inaccessible within two days after an article's release to the public. Conclusion: The prevalence of Internet citations in journals included in PubMed is small (<1%); however, the Inaccessibility rate at the time of publication is considered substantial. Authors, editors, and publishers need to take responsibility for providing accurate and accessible Internet references.
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prevalence and Inaccessibility of urls in the biomedical literature
American Medical Informatics Association Annual Symposium, 2006Co-Authors: Sina Madani, Randy J Carnevale, Stephany N Duda, Michael Feyder, Dominik AronskyAbstract:The World Wide Web is a dynamic environment that does not guarantee permanent access or content stability. We determined the prevalence of URLs in forthcoming, biomedical papers when they are first released in MEDLINE® and prospectively evaluated the rate of inaccessible URLs during a 19-day period. Among 96,153 references from 2,614 forthcoming papers (739 journals) the prevalence of URLs was 0.59%. The rate of inaccessible URLs was 12.4% when first available to the public community.
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AMIA - Prevalence and Inaccessibility of URLs in the biomedical literature.
AMIA ... Annual Symposium proceedings. AMIA Symposium, 2006Co-Authors: Sina Madani, Randy J Carnevale, Stephany N Duda, Michael Feyder, Dominik AronskyAbstract:The World Wide Web is a dynamic environment that does not guarantee permanent access or content stability. We determined the prevalence of URLs in forthcoming, biomedical papers when they are first released in MEDLINE® and prospectively evaluated the rate of inaccessible URLs during a 19-day period. Among 96,153 references from 2,614 forthcoming papers (739 journals) the prevalence of URLs was 0.59%. The rate of inaccessible URLs was 12.4% when first available to the public community.
