The vanilla federated learning is made for a trusted environment, while in contrast, its actual use cases require collaborations in an untrusted setting. For this reason, using blockchain as a ...trusted platform to run federated learning algorithms has gained traction lately and has become a significant research interest. This paper performs a literature survey on state-of-the-art blockchain-based federated learning systems and analyzes several design patterns researchers often take to solve existing issues through blockchain. We find about 31 design item variations throughout the whole system. Each design is further analyzed to find pros and cons, considering fundamental metrics such as robustness, efficiency, privacy, and fairness. The result shows a linear relationship between fairness and robustness in which, if we focus on improving fairness, it will indirectly become more robust. Furthermore, improving all those metrics altogether is not viable because of the efficiency trade-off. Finally, we classify the surveyed papers to spot which designs are popular among researchers and determine which areas require immediate improvements. Our investigation shows that future blockchain-based federated learning systems require more effort regarding model compression, asynchronous aggregation, system efficiency evaluation, and the application for cross-device settings.
Most existing data integrity auditing protocols in cloud storage rely on proof of probabilistic data possession. Consequently, the sampling rate of data integrity verification is low to prevent ...expensive costs to the auditor. However, in the case of a multi-cloud environment, the amount of stored data will be huge. As a result, a higher sampling rate is needed. It will also have an increased cost for the auditor as a consequence. Therefore, this paper proposes a blockchain-based distributed data integrity verification protocol in multi-cloud environments that enables data verification using multi-verifiers. The proposed scheme aims to increase the sampling rate of data verification without increasing the costs significantly. The performance analysis shows that this protocol achieved a lower time consumption required for verification tasks using multi-verifiers than a single verifier. Furthermore, utilizing multi-verifiers also decreases each verifier's computation and communication costs.
The Internet of Things (IoT) providers serve better IoT services each year while producing more IoT gateways and devices to expand their services. However, the security of the IoT ecosystem remains ...an afterthought for most IoT providers. This action results in many cybersecurity breaches in the field, most likely due to the lack of access control mechanisms. In this paper, we propose BorderChain, an access control framework based on blockchain for IoT endpoints. The security protocol guarantees two properties. First, our proposal assures IoT users and services that they communicate with approved IoT gateways as endpoints, holding verified IoT devices that they need. Second, BorderChain also generates access tokens that the IoT service and users can use to query IoT resources legitimately inside the IoT domains. As a result, the protocol can convince IoT domain owners that the system will only authorize IoT requests that they approve. We realize our protocol in the form of a smart contract to allow many IoT entities such as IoT domain owners, IoT devices, IoT gateways, IoT vendors, IoT services, IoT users, and Internet Service Provider (ISP) to collaborate in a unified environment. We then implement entities in BorderChain as Node JS applications connecting to the Ethereum blockchain as our peer-to-peer platform. Based on our performance evaluation using several Raspberry Pi hardware and our private server, we show that BorderChain can process entities' authentication and authorization requests efficiently using all hardware resources. Finally, we release BorderChain for public use.
BACKGROUND:Procedural results for percutaneous coronary intervention (PCI) in coronary vessels with chronic total occlusion (CTO) have improved in recent years, and PCI strategies have moved toward ...more complete revascularization with more liberal use of CTO-PCI. However, evidence evaluating CTO-PCI is limited to observational studies and small clinical trials.
METHODS:In this open-label, multicenter, randomized, noninferiority trial, PCI-eligible patients were assigned to receive either 1 of 2 strategiesPCI or no PCI for the qualifying de novo CTO lesion with the option for PCI of obstructive non-CTO lesions at the discretion of the operator. The primary end point was a composite of death, myocardial infarction, stroke, or any revascularization. Health-related quality of life was assessed at baseline and at 1, 6, 12, 24, and 36 months. Because of slow recruitment, the trial was stopped before completion of the 1284 planned enrollments.
RESULTS:Between March 2010 and September 2016, 834 patients were randomly assigned to the CTO-PCI (n=417) or no CTO-PCI (n=398) strategy. Among the patients assigned to the no CTO-PCI strategy, 78 (19.6%) crossed over to receive staged CTO-PCI within 3 days of randomization. The overall CTO-PCI success rate was 90.6%. Serious nonfatal complications associated with CTO-PCI occurred in 3 patients (1 stroke, 1 cardiac tamponade, and 1 patient with recurrent episodes of ventricular tachyarrhythmia induced by intracoronary thrombus). Approximately half of the patients in each group underwent PCI for an average of 1.3 non-CTO lesions, resulting in a comparable residual SYNTAX score (Synergy Between PCI With TAXUS and Cardiac Surgery; 3.7±5.4 versus 4.0±5.9, P=0.42) confined to non-CTO vessels. During a median follow-up of 4.0 years (interquartile range, 2.4 to 5.1 years), there was no significant difference between the CTO-PCI and the no CTO-PCI strategies in the incidence of the primary end point (22.3% versus 22.4%, hazard ratio, 1.03; 95% CI, 0.77 to 1.37; P=0.86). Both CTO-PCI and no CTO-PCI strategy were associated with significant improvements but without between-group differences in disease-specific health status that was sustained through 36 months.
CONCLUSIONS:CTO-PCI was feasible with high success rates. There was no difference in the incidence of major adverse cardiovascular events with CTO-PCI versus no CTO-PCI, but the study was limited by low power for clinical end points and high crossover rates between groups.
CLINICAL TRIAL REGISTRATION:URLhttps://www.clinicaltrials.gov. Unique identifierNCT01078051.
Atherosclerotic cardiovascular (CV) events commonly occur in individuals with a low CV risk burden. This study evaluated the ability of the triglyceride glucose (TyG) index to predict subclinical ...coronary artery disease (CAD) in asymptomatic subjects without traditional CV risk factors (CVRFs).
This retrospective, cross-sectional, and observational study evaluated the association of TyG index with CAD in 1250 (52.8 ± 6.5 years, 46.9% male) asymptomatic individuals without traditional CVRFs (defined as systolic/diastolic blood pressure ≥ 140/90 mmHg; fasting glucose ≥126 mg/dL; total cholesterol ≥240 mg/dL; low-density lipoprotein cholesterol ≥160 mg/dL; high-density lipoprotein cholesterol < 40 mg/dL; body mass index ≥25.0 kg/m
; current smoking; and previous medical history of hypertension, diabetes, or dyslipidemia). CAD was defined as the presence of any coronary plaque on coronary computed tomographic angiography. The participants were divided into three groups based on TyG index tertiles.
The prevalence of CAD increased with elevating TyG index tertiles (group I: 14.8% vs. group II: 19.3% vs. group III: 27.6%; P < 0.001). Multivariate logistic regression models showed that TyG index was associated with an increased risk of CAD (odds ratio OR 1.473, 95% confidence interval CI 1.026-2.166); especially non-calcified (OR 1.581, 95% CI 1.002-2.493) and mixed plaques (OR 2.419, 95% CI 1.051-5.569) (all P < 0.05). The optimal TyG index cut-off for predicting CAD was 8.44 (sensitivity 47.9%; specificity 68.5%; area under the curve 0.600; P < 0.001). The predictive value of this cut-off improved after considering the non-modifiable factors of old age and male sex.
TyG index is an independent marker for predicting subclinical CAD in individuals conventionally considered healthy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A wireless medical sensor network (WMSN) can sense humans' physiological signs without sacrificing patient comfort and transmit patient vital signs to health professionals' hand-held devices. The ...patient physiological data are highly sensitive and WMSNs are extremely vulnerable to many attacks. Therefore, it must be ensured that patients' medical signs are not exposed to unauthorized users. Consequently, strong user authentication is the main concern for the success and large scale deployment of WMSNs. In this regard, this paper presents an efficient, strong authentication protocol, named E-SAP, for healthcare application using WMSNs. The proposed E-SAP includes: (1) a two-factor (i.e., password and smartcard) professional authentication; (2) mutual authentication between the professional and the medical sensor; (3) symmetric encryption/decryption for providing message confidentiality; (4) establishment of a secure session key at the end of authentication; and (5) professionals can change their password. Further, the proposed protocol requires three message exchanges between the professional, medical sensor node and gateway node, and achieves efficiency (i.e., low computation and communication cost). Through the formal analysis, security analysis and performance analysis, we demonstrate that E-SAP is more secure against many practical attacks, and allows a tradeoff between the security and the performance cost for healthcare application using WMSNs.
Two trials enrolled a total of 2701 patients who had undergone implantation of a drug-eluting coronary stent and had been receiving dual antiplatelet therapy for at least 12 months. They were ...randomly assigned to either continuation or discontinuation of clopidogrel therapy. At 19.2 months after randomization, the rate of myocardial infarction or death from cardiac causes did not differ significantly between the two groups.
Patients who had undergone implantation of a drug-eluting coronary stent and had been receiving dual antiplatelet therapy for at least 12 months were randomly assigned to either continuation or discontinuation of clopidogrel therapy. At 19.2 months after randomization, the rate of myocardial infarction or death from cardiac causes did not differ significantly between the two groups.
Several pivotal clinical trials have shown that the use of drug-eluting coronary stents is associated with significant reductions in the risks of restenosis and need for target-lesion revascularization, as compared with use of bare-metal coronary stents.
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On the basis of the results of these trials, drug-eluting stents have been widely used for percutaneous coronary intervention (PCI) in clinical practice.
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However, some longer-term studies have shown that drug-eluting stents, as compared with bare-metal stents, are associated with increased rates of late stent thrombosis, death, or myocardial infarction.
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It has been proposed that the occurrence of late clinical events may be . . .
Patients with unprotected left main coronary artery stenosis were assigned to either CABG or PCI with sirolimus-eluting stents. At 1 year, with a wide prespecified noninferiority margin, PCI was ...found to be noninferior to CABG.
Anumber of registry reports, as well as a substudy from a large, randomized trial, have indicated that percutaneous coronary intervention (PCI) may be an acceptable alternative to coronary-artery bypass grafting (CABG) in some patients with unprotected left main coronary artery stenosis.
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Recent clinical guidelines have accordingly stated that elective PCI can be considered for patients who have unprotected left main coronary artery disease, although they suggest that the aggregated evidence favors CABG.
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Whether the outcomes after PCI are similar to those after CABG remains uncertain, however, owing to the lack of large, randomized clinical trials. Registry results have . . .
Many researchers challenge the possibility of using blockchain and smart contracts to disrupt the Internet of Things (IoT) architecture because of their security and decentralization guarantees. ...However, the state-of-the-art blockchain architecture is not scalable enough to satisfy the requirements of massive data traffics in the IoT environment. The main reason for this issue is one needs to choose the consensus trade-off between either coping with a high throughput or a high number of nodes. Consequently, this issue prevents the applicability of blockchain for IoT use cases. In this paper, we propose a scalable two-tiered hierarchical blockchain architecture for IoT. The first tier is a Core Engine, which is based on a Practical Byzantine Fault Tolerance (PBFT) consensus to cope with a high throughput, that supervises the underlying subordinate engines (sub-engines) as its second tier. This second tier comprises of the Payment, Compute, and Storage Engine, respectively. We can deploy multiple instances of these sub-engines as many as we need and as local as possible near to the IoT domains, where IoT devices reside, to cope with a high number of nodes. Furthermore, to further extend the scalability of the proposed architecture, we also provide additional scalability features on the Core Engine such as request aggregation, request prioritization, as well as sub-engine parallelism. We implement all of our engines and expose them to IoT applications through the Engine APIs. With these APIs, developers can build and run IoT applications in our architecture. Our evaluation results show that our proposed features on the Core Engine can indeed enhance the overall performance of our architecture. Moreover, based on our proof-of-concept IoT car rental application, we also show that the interoperability between sub-engines through the Core Engine is possible, even when the particular sub-engine is under sub-engine parallelism.
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