101 resultados para Routing protocols


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This thesis proposes Human Associated Delay Tolerant Networks, where data communications among mobile nodes are determined by human social behaviours. Three models are proposed to handle the social attributes effect on data forwarding, the time impact on nodes’ movement and the privacy protection issue when social attributes are introduced.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Competitive athletes completed two studies of 2-h steady-state (SS) cycling at 70% peak O2 uptake followed by 7 kJ/kg time trial (TT) with carbohydrate (CHO) intake before (2 g/kg) and during (6% CHO drink) exercise. In Study A, 12 subjects received either 6 mg/kg caffeine 1 h preexercise (Precaf), 6 × 1 mg/kg caffeine every 20 min throughout SS (Durcaf), 2 × 5 ml/kg Coca-Cola between 100 and 120 min SS and during TT (Coke), or placebo. Improvements in TT were as follows: Precaf, 3.4% (0.2-6.5%, 95% confidence interval); Durcaf, 3.1% (-0.1-6.5%); and Coke, 3.1% (-0.2-6.2%). In Study B, eight subjects received 3 × 5 ml/kg of different cola drinks during the last 40 min of SS and TT: decaffeinated, 6% CHO (control); caffeinated, 6% CHO; decaffeinated, 11% CHO; and caffeinated, 11% CHO (Coke). Coke enhanced TT by 3.3% (0.8-5.9%), with all trials showing 2.2% TT enhancement (0.5-3.8%; P < 0.05) due to caffeine. Overall, 1) 6 mg/kg caffeine enhanced TT performance independent of timing of intake and 2) replacing sports drink with Coca-Cola during the latter stages of exercise was equally effective in enhancing endurance performance, primarily due to low intake of caffeine (∼1.5 mg/kg).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of the research is to develop security protocols for EPC C1G2 RFID Passive Tags in the areas of ownership transfer and grouping proof.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mobile agents are expected to run in partially unknown and untrustworthy environments. They transport from one host to another host through insecure channels and may execute on non-trusted hosts. Thus, they are vulnerable to direct security attacks of intruders and non-trusted hosts. The security of information the agents collect is a fundamental requirement for a trusted implementation of electronic business applications and trade negotiations. This chapter discusses the security protocols presented in the literature that aim to secure the data mobile agents gather while searching the Internet, and identifies the security flaws revealed in the protocols. The protocols are analyzed with respect to the security properties, and the security flaws are identified. Two recent promising protocols that fulfill the various security properties are described. The chapter also introduces common notations used in describing security protocols and describes the security properties of the data that mobile agents gather.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The selection of two high performance liquid chromatography (HPLC) columns with vastly different retention mechanisms is vital for performing effective two-dimensional (2D-) HPLC. This paper reports on a systematic method to select a pair of HPLC columns that provide the most different separations for a given sample. This was completed with the aid of a HPLC simulator that predicted retention profiles on the basis of real experimental data, which is difficult when the contents of sample matrices are largely-or completely-unknown. Peaks from the same compounds must first be matched between chromatograms to compare the retention profiles and optimised 2D-HPLC column selection. In this work, two methods of matching peaks between chromatograms were explored and an optimal pair of chromatography columns was selected for 2D-HPLC. First, a series of 17 antioxidants were selected as an analogue for a coffee extract. The predicted orthogonality of the standards was 39%, according to the fractional surface coverage 'bins' method, which was close to the actual space utilisation of the standard mixture, 44%. Moreover, the orthogonality for the 2D-HPLC of coffee matched the predicted value of 38%. The second method employed a complex sample matrix of urine to optimise the column selections. Seven peaks were confidently matched between chromatograms by comparing relative peak areas of two detection strategies: UV absorbance and potassium permanganate chemiluminescence. It was found that the optimal combinations had an orthogonality of 35% while the actual value was closer to 30%.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

AIMS: Assess the effects of protocol-directed sedation management on the duration of mechanical ventilation and other relevant patient outcomes in mechanically ventilated intensive care unit patients. BACKGROUND: Sedation is a core component of critical care. Sub-optimal sedation management incorporates both under- and over-sedation and has been linked to poorer patient outcomes. DESIGN: Cochrane systematic review of randomized controlled trials. DATA SOURCES: Cochrane Central Register of Controlled trials, MEDLINE, EMBASE, CINAHL, Database of Abstracts of Reviews of Effects, LILACS, Current Controlled Trials and US National Institutes of Health Clinical Research Studies (1990-November 2013) and reference lists of articles were used. REVIEW METHODS: Randomized controlled trials conducted in intensive care units comparing management with and without protocol-directed sedation were included. Two authors screened titles, abstracts and full-text reports. Potential risk of bias was assessed. Clinical, methodological and statistical heterogeneity were examined and the random-effects model used for meta-analysis where appropriate. Mean difference for duration of mechanical ventilation and risk ratio for mortality, with 95% confidence intervals, were calculated. RESULTS: Two eligible studies with 633 participants comparing protocol-directed sedation delivered by nurses vs. usual care were identified. There was no evidence of differences in duration of mechanical ventilation or hospital mortality. There was statistically significant heterogeneity between studies for duration of mechanical ventilation. CONCLUSIONS: There is insufficient evidence to evaluate the effectiveness of protocol-directed sedation as results from the two randomized controlled trials were conflicting.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Finding practical ways to robustly estimate abundance or density trends in threatened species is a key facet for effective conservation management. Further identifying less expensive monitoring methods that provide adequate data for robust population density estimates can facilitate increased investment into other conservation initiatives needed for species recovery. Here we evaluated and compared inference-and cost-effectiveness criteria for three field monitoring-density estimation protocols to improve conservation activities for the threatened Komodo dragon (Varanus komodoensis). We undertook line-transect counts, cage trapping and camera monitoring surveys for Komodo dragons at 11 sites within protected areas in Eastern Indonesia to collect data to estimate density using distance sampling methods or the Royle-Nichols abundance induced heterogeneity model. Distance sampling estimates were considered poor due to large confidence intervals, a high coefficient of variation and that false absences were obtained in 45 % of sites where other monitoring methods detected lizards present. The Royle-Nichols model using presence/absence data obtained from cage trapping and camera monitoring produced highly correlated density estimates, obtained similar measures of precision and recorded no false absences in data collation. However because costs associated with camera monitoring were considerably less than cage trapping methods, albeit marginally more expensive than distance sampling, better inference from this method is advocated for ongoing population monitoring of Komodo dragons. Further the cost-savings achieved by adopting this field monitoring method could facilitate increased expenditure on alternative management strategies that could help address current declines in two Komodo dragon populations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Control of introduced predators to mitigate biodiversity impacts is a pressing conservation challenge. Across Australia feral cats (Felis catus) are a major threat to terrestrial biodiversity. Currently feral cat control is hindered by the limited utility of existing predator baiting methods. Further proposed control methods include use of the novel poison para-aminopropiophenone (PAPP) which may present a hazard to some native animal populations. Here we used experimental and predictive approaches to evaluate feral cat bait take by a large native Australian predatory reptile the Lace monitor (Varanus varius). These lizards would be expected to readily detect, ingest and consume a lethal dose (depending on toxin) from surface-laid baits intended for feral cat control if a precautionary approach was not adopted when baiting. We modelled V. varius bait take using experimental and predictive biophysical modelling approaches to evaluate temporal effects of climate variables on V. varius activity and hence potential for bait removal. Finally we conducted a pre-PAPP baiting site occupancy assessment of V. varius within Wilson Promontory National Park (WPNP) to provide a basis for monitoring any longer term population effects of cat baiting. V. varius removed 7 % of deployed baits from 73 % of bait stations across another study area in Far Eastern Victoria. Daily bait removal was positively correlated with maximum temperature and solar radiation. Biophysical modelling for Far Eastern Victoria predicted that maximum temperatures <19.5 °C prevented V. varius activity and hence opportunity for bait removal. V. varius in WPNP was undetectable suggesting aerial baiting posed limited hazard to this species at this location. Depending how climate influences annual activity patterns and the specific poison, surface-laid baits could pose a significant mortality risk to V. varius. However, use of biophysical models to predict periods of V. varius inactivity may provide a novel means to reduce non-target bait take by this predator.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Vehicular Cyber-Physical System (VCPS) provides CPS services via exploring the sensing, computing and communication capabilities on vehicles. VCPS is deeply influenced by the performance of the underlying vehicular network with intermittent connections, which make existing routing solutions hardly to be applied directly. Epidemic routing, especially the one using random linear network coding, has been studied and proved as an efficient way in the consideration of delivery performance. Much pioneering work has tried to figure out how epidemic routing using network coding (ERNC) performs in VCPS, either by simulation or by analysis. However, none of them has been able to expose the potential of ERNC accurately. In this paper, we present a stochastic analytical framework to study the performance of ERNC in VCPS with intermittent connections. By novelly modeling ERNC in VCPS using a token-bucket model, our framework can provide a much more accurate results than any existing work on the unicast delivery performance analysis of ERNC in VCPS. The correctness of our analytical results has also been confirmed by our extensive simulations.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Wireless mesh networks are widely applied in many fields such as industrial controlling, environmental monitoring, and military operations. Network coding is promising technology that can improve the performance of wireless mesh networks. In particular, network coding is suitable for wireless mesh networks as the fixed backbone of wireless mesh is usually unlimited energy. However, coding collision is a severe problem affecting network performance. To avoid this, routing should be effectively designed with an optimum combination of coding opportunity and coding validity. In this paper, we propose a Connected Dominating Set (CDS)-based and Flow-oriented Coding-aware Routing (CFCR) mechanism to actively increase potential coding opportunities. Our work provides two major contributions. First, it effectively deals with the coding collision problem of flows by introducing the information conformation process, which effectively decreases the failure rate of decoding. Secondly, our routing process considers the benefit of CDS and flow coding simultaneously. Through formalized analysis of the routing parameters, CFCR can choose optimized routing with reliable transmission and small cost. Our evaluation shows CFCR has a lower packet loss ratio and higher throughput than existing methods, such as Adaptive Control of Packet Overhead in XOR Network Coding (ACPO), or Distributed Coding-Aware Routing (DCAR).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The popularity of smartphones has led to an increasing demand for health apps. As a result, the healthcare industry is embracing mobile technology and the security of mHealth is essential in protecting patient’s user data and WBAN in a clinical setting. Breaches of security can potentially be life-threatening as someone with malicious intentions could misuse mHealth devices and user information. In this article, threats to security for mHealth networks are discussed in a layered approach addressing gaps in this emerging field of research. Suite B and Suite E, which are utilized in many security systems, including in mHealth applications, are also discussed. In this paper, the support for mHealth security will follow two approaches; protecting patient-centric systems and associated link technologies. Therefore this article is focused on the security provisioning of the communication path between the patient terminal (PT; e.g., sensors) and the monitoring devices (e.g., smartphone, data-collector).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study was conducted to protect security of human beings and businesses from intruders in the context of IoT which is next generation internet. We have developed a universal framework and a number of communication protocols to provide security that will make IoT cyber world safer for all t users.