By means of advanced information and communication technology, cyber-physical power systems can attain real-time monitor and control but have to suffer the damage caused by a cyber attack. In this ...study, the authors' define attack efficiency to evaluate attack paths that attacker may adopt to intrude systems, to find the most efficient attack paths (i.e. the most vulnerable paths). Based on the actual power grid and security stability control system, the coupling model of cyber-physical power systems is established to analyse the propagation of cascading failure within and across the physical power grid and communication network. In the attack model, the attack cost matrix is built to describe the cost between directly connected nodes in a communication network. Furthermore, considering the probability that control commands are successfully transmitted from router nodes to generator/substation nodes, the total attack cost from the communication network to the physical power grid is figured out. To search for the most vulnerable attack paths in systems, the attack efficiency is proposed to quantify the relation between attack cost and attack gain, wherein the attack gain is the damage on systems caused by the cyber attack.
Prior randomized trials have generally shown harm or no benefit of stenting added to medical therapy for patients with symptomatic severe intracranial atherosclerotic stenosis, but it remains ...uncertain as to whether refined patient selection and more experienced surgeons might result in improved outcomes.
To compare stenting plus medical therapy vs medical therapy alone in patients with symptomatic severe intracranial atherosclerotic stenosis.
Multicenter, open-label, randomized, outcome assessor-blinded trial conducted at 8 centers in China. A total of 380 patients with transient ischemic attack or nondisabling, nonperforator (defined as nonbrainstem or non-basal ganglia end artery) territory ischemic stroke attributed to severe intracranial stenosis (70%-99%) and beyond a duration of 3 weeks from the latest ischemic symptom onset were recruited between March 5, 2014, and November 10, 2016, and followed up for 3 years (final follow-up: November 10, 2019).
Medical therapy plus stenting (n = 176) or medical therapy alone (n = 182). Medical therapy included dual-antiplatelet therapy for 90 days (single antiplatelet therapy thereafter) and stroke risk factor control.
The primary outcome was a composite of stroke or death within 30 days or stroke in the qualifying artery territory beyond 30 days through 1 year. There were 5 secondary outcomes, including stroke in the qualifying artery territory at 2 years and 3 years as well as mortality at 3 years.
Among 380 patients who were randomized, 358 were confirmed eligible (mean age, 56.3 years; 263 male 73.5%) and 343 (95.8%) completed the trial. For the stenting plus medical therapy group vs medical therapy alone, no significant difference was found for the primary outcome of risk of stroke or death (8.0% 14/176 vs 7.2% 13/181; difference, 0.4% 95% CI, -5.0% to 5.9%; hazard ratio, 1.10 95% CI, 0.52-2.35; P = .82). Of the 5 prespecified secondary end points, none showed a significant difference including stroke in the qualifying artery territory at 2 years (9.9% 17/171 vs 9.0% 16/178; difference, 0.7% 95% CI, -5.4% to 6.7%; hazard ratio, 1.10 95% CI, 0.56-2.16; P = .80) and 3 years (11.3% 19/168 vs 11.2% 19/170; difference, -0.2% 95% CI, -7.0% to 6.5%; hazard ratio, 1.00 95% CI, 0.53-1.90; P > .99). Mortality at 3 years was 4.4% (7/160) in the stenting plus medical therapy group vs 1.3% (2/159) in the medical therapy alone group (difference, 3.2% 95% CI, -0.5% to 6.9%; hazard ratio, 3.75 95% CI, 0.77-18.13; P = .08).
Among patients with transient ischemic attack or ischemic stroke due to symptomatic severe intracranial atherosclerotic stenosis, the addition of percutaneous transluminal angioplasty and stenting to medical therapy, compared with medical therapy alone, resulted in no significant difference in the risk of stroke or death within 30 days or stroke in the qualifying artery territory beyond 30 days through 1 year. The findings do not support the addition of percutaneous transluminal angioplasty and stenting to medical therapy for the treatment of patients with symptomatic severe intracranial atherosclerotic stenosis.
ClinicalTrials.gov Identifier: NCT01763320.
The field of information security is a fast-growing discipline. Even though the effectiveness of security measures to protect sensitive information is increasing, people remain susceptible to ...manipulation and thus the human element remains a weak link. A social engineering attack targets this weakness by using various manipulation techniques to elicit sensitive information. The field of social engineering is still in its early stages with regard to formal definitions, attack frameworks and templates of attacks. This paper proposes detailed social engineering attack templates that are derived from real-world social engineering examples. Current documented examples of social engineering attacks do not include all the attack steps and phases. The proposed social engineering attack templates attempt to alleviate the problem of limited documented literature on social engineering attacks by mapping the real-world examples to the social engineering attack framework. Mapping several similar real-world examples to the social engineering attack framework allows one to establish a detailed flow of the attack whilst abstracting subjects and objects. This mapping is then utilised to propose the generalised social engineering attack templates that are representative of real-world examples, whilst still being general enough to encompass several different real-world examples. The proposed social engineering attack templates cover all three types of communication, namely bidirectional communication, unidirectional communication and indirect communication. In order to perform comparative studies of different social engineering models, processes and frameworks, it is necessary to have a formalised set of social engineering attack scenarios that are fully detailed in every phase and step of the process. The social engineering attack templates are converted to social engineering attack scenarios by populating the template with both subjects and objects from real-world examples whilst still maintaining the detailed flow of the attack as provided in the template. Furthermore, this paper illustrates how the social engineering attack scenarios are applied to verify a social engineering attack detection model. These templates and scenarios can be used by other researchers to either expand on, use for comparative measures, create additional examples or evaluate models for completeness. Additionally, the proposed social engineering attack templates can also be used to develop social engineering awareness material.
Background and purposeStroke is the leading cause of mortality and disability in China. Precise aetiological classification, imaging and biological markers may predict the prognosis of stroke. The ...Third China National Stroke Registry (CNSR-III), a nationwide registry of ischaemic stroke or transient ischaemic attack (TIA) in China based on aetiology, imaging and biology markers, will be considered to clarify the pathogenesis and prognostic factors of ischaemic stroke.MethodsBetween August 2015 and March 2018, the CNSR-III recruited consecutive patients with ischaemic stroke or TIA from 201 hospitals that cover 22 provinces and four municipalities in China. Clinical data were collected prospectively using an electronic data capture system by face-to-face interviews. Patients were followed for clinical outcomes at 3 months, 6 months and 1–5 year annually. Brain imaging, including brain MRI and CT, were completed at baseline. Blood samples were collected and biomarkers were tested at baseline.ResultsA total of 15 166 stroke patients were enrolled, among which 31.7% patients were women with the average age of 62.2±11.3 years. Ischaemic stroke was predominant (93.3%, n=14 146) and 1020 (6.7%) TIAs were enrolled.ConclusionsCNSR-III is a large scale nationwide registry in China. Data from this prospective registry may provide opportunity to evaluate imaging and biomarker prognostic determinants of stroke.
This article investigates the synchronization control problem of fuzzy complex dynamic networks (FCDNs) with diversified network attacks. By making full use of the weighted historically released ...packets, a novel anti-attack memory-based adaptive event-triggered protocol (AETP) and the corresponding anti-attack fuzzy memory-based controller are introduced by taking the sporadic denial-of-service (DoS) and deceptive attacks into consideration concurrently. Compared with the conventional event-triggered protocols and AETPs, the developed anti-attack memory-based AETP cannot only effectually reduce the frequency of event triggers, but also enhance the transient performance of FCDNs. In addition, in view of a new sampling-instant-dependent piecewise Lyapunov functional, less conservative criteria are induced to guarantee that the stochastically exponential synchronization of FCDNs is accomplished in the case where the deceptive and sporadic DoS attacks coexist. Finally, the merits and validity of the theoretical results are illustrated through numerical examples.
•In general, the cyber-attacks in the literature can be classified into three main types: denial of service (DoS) attacks, deception attacks, and replay attacks. The focus of this paper will be on ...each of the aforementioned attacks such that the modeling and detection of each attack will be addressed, and the control of CPS under such attack will be discussed in details.•After a preliminary introduction of the subject, the paper is organized as follows. Detection of cyber-attacks are summarized in Section 2. In Section 3 the DoS attack is addressed. In Section 4, the results on the deception attack are given. Section 5 covers the replay attack.•Finally, challenges and future work are discussed in Section 6.
Cyber Physical Systems (CPS) are almost everywhere; they can be accessed and controlled remotely. These features make them more vulnerable to cyber attacks. Since these systems provide critical services, having them under attack would have dangerous consequences. Unfortunately, cyber attacks may be detected, but after the damage is done. Therefore, developing a cyber system that can survive an attack is a challenge. In this paper, we are surveying the literature on security aspects of CPSs. First, we present some of existing methods for detecting cyber attacks. Second, we focus on three main cyber attacks, which are: Denial of service (DoS), deception, and replay attacks. In our discussion, we have surveyed some exiting models of these attacks, approaches of filtering CPS subject to these attacks, and approaches of control CPS subject to these attacks.
In this article, the problem of simultaneous cyberattack and fault detection and isolation (CAFDI) for both centralized and large-scale interconnected cyber-physical systems (CPSs) is studied. The ...proposed methodologies include centralized and distributed CAFDI approaches, which involve the use of two filters on the plant and command and control (C&C) sides of the CPS, as well as an unknown input observer (UIO)-based detector on the plant side. The article characterizes the conditions under which the proposed methodologies can detect various types of deception attacks, such as covert attacks, zero dynamics attacks, and replay attacks. In the proposed centralized CAFDI methodology, the transmission of estimates from the C&C side filter to the plant side is required, with the assumption that a certain number of communication channels are secured. Consequently, a bank UIO-based detectors are utilized on the plant side to detect and isolate anomalies. It is also assumed that adversaries have knowledge of system parameters, filters, and the UIO-based detector. To address the limitations of secure communication channels, modifications to the two side filters and the UIO-based detector have been developed and implemented that eliminates the need for any secured communication channel in the modified CAFDI module. However, information must now be sent to and received from the plant side filter. Consequently, we develop a distributed CAFDI methodology for the interconnected large-scale CPS which consists of several subsystems. Finally, a hardware-in-the-loop (HIL) simulation of a four-area power network system under presence of both cyberattacks and faults using an OPAL-RT real-time simulator and Raspberry Pi is provided to illustrate the effectiveness of our proposed distributed CAFDI methodology.
This paper analyzed the existing network security situation evaluation methods and discovered that they cannot accurately reflect the features of large-scale, synergetic, multi-stage gradually shown ...by network attack behaviors. For this purpose, the association between attack intention and network configuration information was deep analyzed. Then a network security situation evaluation method based on attack intention recognition was proposed. Unlike traditional method, the evaluation method was based on intruder. This method firstly made causal analysis of attack event and discovered and simplified intrusion path to recognize every attack phases, then realized situation evaluation based on the attack phases. Lastly attack intention was recognized and next attack phase was forecasted based on achieved attack phases, combined with vulnerability and network connectivity. A simulation experiments for the proposed network security situation evaluation model is performed by network examples. The experimental results show that this method is more accurate on reflecting the truth of attack. And the method does not need training on the historical sequence, so the method is more effective on situation forecasting.
Risk of dementia after stroke is a major concern for patients and carers. Reliable data for risk of dementia, particularly after transient ischaemic attack or minor stroke, are scarce. We studied the ...risks of, and risk factors for, dementia before and after transient ischaemic attack and stroke.
The Oxford Vascular Study is a prospective incidence study of all vascular events in a population of 92 728 people residing in Oxfordshire, UK. Patients with transient ischaemic attack or stroke occurring between April 1, 2002, and March 31, 2012, were ascertained with multiple methods, including assessment in a dedicated daily emergency clinic and daily review of all hospital admissions. Pre-event and post-event (incident) dementia were diagnosed at initial assessment and during 5-years' follow-up on the basis of cognitive testing supplemented by data obtained from hand searches of all hospital and primary care records. We assessed the association between post-event dementia and stroke severity (as measured with the US National Institutes of Health Stroke Scale NIHSS score), location (ie, dysphasia), previous events, markers of susceptibility or reserve (age, low education, pre-morbid dependency, leucoaraiosis), baseline cognition, and vascular risk factors with Cox regression models adjusted for age, sex, and education. We compared incidence and prevalence of dementia in our population with published UK population age-matched and sex-matched rates.
Among 2305 patients (mean age 74·4 years SD 13·0), 688 (30%) had transient ischaemic attacks and 1617 (70%) had strokes. Pre-event dementia was diagnosed in 225 patients; prevalence was highest in severe stroke (ie, NIHSS >10) and lowest in transient ischaemic attack. Of 2080 patients without pre-event dementia, 1982 (95%) were followed up to the end of study or death. Post-event dementia occurred in 432 of 2080 patients during 5 years of follow-up. The incidence of post-event dementia at 1 year was 34·4% (95% CI 29·7–41·5) in patients with severe stroke (NIHSS score >10), 8·2% (6·2–10·2) in those with minor stroke (NIHSS score <3), and 5·2% (3·4–7·0) in those with transient ischaemic attack. Compared with the UK age-matched and sex-matched population, the 1-year standardised morbidity ratio for the incidence of dementia was 47·3 (95% CI 35·9–61·2), 5·8 (4·4–7·5), and 3·5 (2·5–4·8), respectively. Consequently, prevalence of dementia in 1-year survivors was brought forward by approximately 25 years in those who had severe strokes, 4 years in those who had minor strokes, and 2 years in those who had transient ischaemic attacks. 5-year risk of dementia was associated with age, event severity, previous stroke, dysphasia, baseline cognition, low education, pre-morbid dependency, leucoaraiosis, and diabetes (p<0·0001 for all comparisons, except for previous stroke p=0·006).
The incidence of dementia in patients who have had a transient ischaemic attack or stroke varies substantially depending on clinical characteristics including lesion burden and susceptibility factors. Incidence of dementia is nearly 50 times higher in the year after a major stroke compared with that in the general population, but excess risk is substantially lower after transient ischaemic attack and minor stroke.
Wellcome Trust, Wolfson Foundation, British Heart Foundation, National Institute for Health Research, and the National Institute for Health Research Oxford Biomedical Research Centre.
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