15 research outputs found

    Identifying the Strengths and Weaknesses of Over-the-Shoulder Attack Resistant Prototypical Graphical Authentication Schemes

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    Authentication verifies users’ identities to protect against costly attacks. Graphical authentication schemes utilize pictures as passcodes rather than strings of characters. Pictures have been found to be more memorable than the strings of characters used in alphanumeric passwords. However, graphical passcodes have been criticized for being susceptible to Over-the-Shoulder Attacks (OSA). To overcome this concern, many graphical schemes have been designed to be resistant to OSA. Security to this type of attack is accomplished by grouping targets among distractors, translating the selection of targets elsewhere, disguising targets, and using gaze-based input. Prototypical examples of graphical schemes that use these strategies to bolster security against OSAs were directly compared in within-subjects runoffs in studies 1 and 2. The first aim of this research was to discover the current usability limitations of graphical schemes. The data suggested that error rates are a common issue among graphical passcodes attempting to resist OSAs. Studies 3 and 4 investigated the memorability of graphical passcodes when users need to remember multiple passcodes or longer passcodes. Longer passcodes provide advantages to security by protecting against brute force attacks, and multiple passcodes need to be investigated as users need to authenticate for numerous accounts. It was found that participants have strong item retention for passcodes of up to eight images and for up to eight accounts. Also these studies leveraged context to facilitate memorability. Context slightly improved the memorability of graphical passcodes when participants needed to remember credentials for eight accounts. These studies take steps toward understanding the readiness of graphical schemes as an authentication option

    Trust and Complacency in Cyber Security

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    Improved understanding of conditions that foster appropriate use of security tools by cyber security professionals is crucial for protecting companies from financial losses. Trust has been an important topic in the literature because of its role in allowing for cooperation among humans and automation and because of its relationship with appropriate use. The current study aimed to extend the finding that high trust leads to complacency in the domain of cyber security and to clarify a discrepancy in the literature about complacency’s operationalization by measuring information sampling behaviors directly. The sample consisted of 101 first year psychology students. The independent variable was the reliability of an intrusion detection system (IDS), and complacency and self-report trust were dependent measures. Trust was measured by a self-report questionnaire (Jian et al., 2000). Complacency was measured by reverse coding the number of clicks used to drill down for information in log files in a simulated IDS. Information sampling behavior provides a more direct and accurate measure of complacency than previously used performance measures. It was hypothesized that when supervising an IDS, high reliability of the IDS would lead to complacency, and trust with automation would mediate this relationship. Although reliability was found to predict both trust and complacency, the mediation was not supported. Results suggest new considerations in measuring trust in laboratory and field settings

    Postoperative continuous positive airway pressure to prevent pneumonia, re-intubation, and death after major abdominal surgery (PRISM): a multicentre, open-label, randomised, phase 3 trial

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    Background: Respiratory complications are an important cause of postoperative morbidity. We aimed to investigate whether continuous positive airway pressure (CPAP) administered immediately after major abdominal surgery could prevent postoperative morbidity. Methods: PRISM was an open-label, randomised, phase 3 trial done at 70 hospitals across six countries. Patients aged 50 years or older who were undergoing elective major open abdominal surgery were randomly assigned (1:1) to receive CPAP within 4 h of the end of surgery or usual postoperative care. Patients were randomly assigned using a computer-generated minimisation algorithm with inbuilt concealment. The primary outcome was a composite of pneumonia, endotracheal re-intubation, or death within 30 days after randomisation, assessed in the intention-to-treat population. Safety was assessed in all patients who received CPAP. The trial is registered with the ISRCTN registry, ISRCTN56012545. Findings: Between Feb 8, 2016, and Nov 11, 2019, 4806 patients were randomly assigned (2405 to the CPAP group and 2401 to the usual care group), of whom 4793 were included in the primary analysis (2396 in the CPAP group and 2397 in the usual care group). 195 (8\ub71%) of 2396 patients in the CPAP group and 197 (8\ub72%) of 2397 patients in the usual care group met the composite primary outcome (adjusted odds ratio 1\ub701 [95% CI 0\ub781-1\ub724]; p=0\ub795). 200 (8\ub79%) of 2241 patients in the CPAP group had adverse events. The most common adverse events were claustrophobia (78 [3\ub75%] of 2241 patients), oronasal dryness (43 [1\ub79%]), excessive air leak (36 [1\ub76%]), vomiting (26 [1\ub72%]), and pain (24 [1\ub71%]). There were two serious adverse events: one patient had significant hearing loss and one patient had obstruction of their venous catheter caused by a CPAP hood, which resulted in transient haemodynamic instability. Interpretation: In this large clinical effectiveness trial, CPAP did not reduce the incidence of pneumonia, endotracheal re-intubation, or death after major abdominal surgery. Although CPAP has an important role in the treatment of respiratory failure after surgery, routine use of prophylactic post-operative CPAP is not recommended

    International Society for Therapeutic Ultrasound Conference 2016

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    Effect of Antiplatelet Therapy on Survival and Organ Support–Free Days in Critically Ill Patients With COVID-19

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    International audienc

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    Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

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    Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally
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