115 research outputs found

    Adaptive Anomaly Detection via Self-Calibration and Dynamic Updating

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    The deployment and use of Anomaly Detection (AD) sensors often requires the intervention of a human expert to manually calibrate and optimize their performance. Depending on the site and the type of traffic it receives, the operators might have to provide recent and sanitized training data sets, the characteristics of expected traffic (i.e. outlier ratio), and exceptions or even expected future modifications of system's behavior. In this paper, we study the potential performance issues that stem from fully automating the AD sensors' day-to-day maintenance and calibration. Our goal is to remove the dependence on human operator using an unlabeled, and thus potentially dirty, sample of incoming traffic. To that end, we propose to enhance the training phase of AD sensors with a self-calibration phase, leading to the automatic determination of the optimal AD parameters. We show how this novel calibration phase can be employed in conjunction with previously proposed methods for training data sanitization resulting in a fully automated AD maintenance cycle. Our approach is completely agnostic to the underlying AD sensor algorithm. Furthermore, the self-calibration can be applied in an online fashion to ensure that the resulting AD models reflect changes in the system's behavior which would otherwise render the sensor's internal state inconsistent. We verify the validity of our approach through a series of experiments where we compare the manually obtained optimal parameters with the ones computed from the self-calibration phase. Modeling traffic from two different sources, the fully automated calibration shows a 7.08% reduction in detection rate and a 0.06% increase in false positives, in the worst case, when compared to the optimal selection of parameters. Finally, our adaptive models outperform the statically generated ones retaining the gains in performance from the sanitization process over time

    Factors influencing mentors’ satisfaction: A study from medical schools in Norway and Canada

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    Phenomenon: The mentoring of undergraduate medical students has been shown to benefit the mentors; however, detailed information on the factors that influence the satisfaction and motivation of mentors remains unclear. Such knowledge can be useful in sustaining group mentorship programs. The aim of this study was to investigate the experiences and perspectives of mentors to ascertain the factors that contribute to satisfaction and motivation. Approach: As part of a larger research project, a survey was sent out to mentors at UiT the Arctic University of Norway, the University of Bergen and McGill University (N=461). Descriptive statistics, linear regression and factor analyses were used to examine the data in order to map factors associated with mentor satisfaction. Findings: The overall response rate was 59% (n=272/461). Mentors reported a high mean satisfaction score of 4.55 (±0.04, median 5.00) on a five-point Likert scale. Six out of nine statements describing how mentors approach group mentoring were strongly correlated with each other. Through factor analysis of the items, we found a dominating factor labeled “Student-centered mentoring approach” which was strongly associated with the level of satisfaction as a mentor. Additionally, highly satisfied mentors took a greater interest in patient-centered medicine and their students’ personal development. Their groups spent more time discussing students’ clinical experiences, societal poverty and health, and patients’ suffering and sickness. Insights: Our findings suggest that high mentor satisfaction, which is important for the pedagogical quality and sustainability of mentor programs, is related to the mentors’ student-centeredness and their interest in topics concerning professionalism. By preparing mentors for their roles and supporting them in developing strategies for establishing good mentoring relationships, the outcomes of group mentoring may be improved both for mentors and students. Interest in students’ personal development and the mentors’ own professional development seem to be indicators of mentors’ satisfaction and should be encouraged in mentorship programs

    Self-reported medication information needs among medication users in a general population aged 40 years and above – the Tromsø study

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    Purpose: To determine the prevalence and associated factors of self-reported medication information needs among medication users in a general population aged 40 years and above – The Tromsø Study. Methods: Cross-sectional study of medication users (n=10,231) among participants in the Tromsø Study, a descriptive analysis of questionnaire data and multivariable logistic regression (n=9,194). Results: Sixteen percent of medication users expressed a need for more information about own medications. Overall, medication users agreed to a higher degree to have received information from the GP compared to the pharmacy. Concerned medication users and those disagreeing to have received information about side effects had the highest odds for needing more information (OR 5.07, 95% CI 4.43–5.81) and (OR 2.21, 95% CI 1.83–2.68), respectively. Medication users who used heart medications (e.g., nitroglycerin, antiarrhythmics, anticoagulants) (OR 1.71, 95% CI 1.46–2.01), medication for hypothyroidism (OR 1.36, 95% CI 1.13–1.64) or had moderately health anxiety had expressed need for medication information. Whereas medication users with lower education, those that never used internet to search for health advice, and medication users who disagreed to have received information about reason for-use were associated with lower odds (OR 0.75, 95% CI 0.62–0.91), (OR 0.85, 95% CI 0.74–0.98) and (OR 0.68, 95% CI 0.53–0.88), respectively. Conclusion: This study demonstrated that there is need for more information about own medications in a general population aged 40 years and above and shed light on several characteristics of medication users with expressed information need which is important when tailoring the right information to the right person

    Enhancing Network Security: Host Trustworthiness Estimation

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    Network connected devices has become inherent part of our lives. These devices have come to be more and more mobile and are target of various malware attacks. An inability to guarantee or check proper security settings of such devices poses a serious risk to network security. In this paper we propose a novel concept of flow based host trustworthiness estimation. The estimated trustworthiness determines a level of the risk to the network security the host posses. This concept enables network operators to identify a potential dangerous host in their network and take an appropriate precautions. Models used for trustworthiness estimation are based on scoring either single events or host characteristics. In order to be able to estimate trustworthiness of a host even in large scale networks, the data used for estimation are reduced only to extended network flows. The research is in its initial phase and will conclude with Ph.D. thesis in three years.Zařízení připojené do sítě se stala neodmyslitelnou součástí našeho života. Tyto zařízení jsou stále mobilnější a stávají se cílem různých druhů škodlivého softwaru. Neschopnost zaručit či prověřit správné nastavení bezpečnostního zajištění těchto zařízení představuje nezanedbatelné riziko pro bezpečnost počítačové sítě. V tomto článku je představen koncept pro odhadování míry důvěryhodnosti daného zařízení. Míra důvěryhodnosti reprezentuje míru rizika, kterou zařízení představuje pro síťovou bezpečnost. Tento koncept umožní správcům sítě identifikovat potenciálně nebezpečné zařízení. Modely pro odhadování důvěryhodnosti jsou založeny na scoringu buď jednotlivých událostí nebo charakteristik zařízení. Aby bylo možné odhadovat důvěryhodnost zařízené dokonce i v rozsáhlých sítích, pro odhad důvěryhodnosti jsou využívána pouze data ze síťových toků. Výzkum je v jeho počáteční fázi a bude v horizontu tří let završen disertační prací

    Absence of the common Insulin-like growth factor-1 19-repeat allele is associated with early age at breast cancer diagnosis in multiparous women

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    Multiparity decreases the risk of breast cancer in white women, whereas it is a risk factor in black women <50 years. Early-onset breast cancer (<50 years) has been associated with high insulin-like growth factor-1 (IGF-1) levels. Absence of the common IGF1 19 cytosine-adenine (CA)-repeat allele (IGF1-19/-19) inverts the effect of several non-genetic factors on breast cancer risk but the interaction between IGF1-19/-19 and multiparity on breast cancer risk is unknown. As IGF1-19/-19, multiparity and early-onset breast cancer are more common in black than in white women, we aimed to study whether multiparity combined with IGF1-19/-19 increases the risk of early-onset breast cancer. Four hundred and three breast cancer patients diagnosed in Lund, Sweden, at age 25–99 years were genotyped for the IGF1 CA-repeat length using fragment analysis. Overall, 12.9% carried the IGF1-19/-19 genotype. There was a highly significant interaction between multiparity and IGF1-19/-19 on age at breast cancer diagnosis (P=0.007). Among IGF1-19/-19 patients, multiparity was associated with a 9.2 year earlier age at diagnosis compared with uniparity or nulliparity (P=0.006). Multiparity combined with IGF1-19/-19 was associated with an early age at breast cancer diagnosis. If confirmed, IGF1-19/-19 may help identify a subgroup of women for earlier breast cancer screening

    Coffee intake and CYP1A2*1F genotype predict breast volume in young women: implications for breast cancer

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    As breast volume may be associated with heart cancer risk, we studied the relationship between breast volume, CYP1A2*1F and coffee intake. Among healthy premenopausal non-hormone users, 3+ cups per day was associated with lower volume only in C-allele carriers (Pinteraction=0.02), which is consistent with reports that coffee protects only C-allele carriers against breast cancer

    The occurrence of invasive cancers following a diagnosis of breast carcinoma in situ

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    Approximately 1 in every 600 women attending breast-screening programmes in the United Kingdom is diagnosed with breast carcinoma in situ (BCIS). However, there is little information on the occurrence of subsequent cancers (other than second breast cancers) in these women. We investigated the occurrence of invasive cancers in 12 836 women diagnosed with BCIS in southeast England between 1971 and 2003, using data from the Thames Cancer Registry. A greater than expected number of subsequent cancers was found for two sites: breast (standardised incidence ratio (SIR) 1.96; 95% confidence interval (CI) 1.79–2.14) and corpus uteri (SIR 1.42; 95% CI 1.11–1.78). For subsequent ipsilateral breast cancer in those treated with breast conservation, the excess was independent of the time since diagnosis of BCIS, whereas for subsequent contralateral breast cancer, there was a steady decline in excess over time. For subsequent uterine cancer, the excess became statistically significant only at >5 years after BCIS diagnosis, consistent with a treatment effect. This was further supported by Cox regression anaysis: the risk of subsequent uterine cancer was significantly increased in women receiving hormonal therapy compared with those not receiving it, with a hazard ratio of 2.97 (95% CI 1.84–4.80)

    Clinical manifestations and outcome in Staphylococcus aureus endocarditis among injection drug users and nonaddicts: a prospective study of 74 patients

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    BACKGROUND: Endocarditis is a common complication in Staphylococcus aureus bacteremia (SAB). We compared risk factors, clinical manifestations, and outcome in a large, prospective cohort of patients with S. aureus endocarditis in injection drug users (IDUs) and in nonaddicts. METHODS: Four hundred and thirty consecutive adult patients with SAB were prospectively followed up for 3 months. Definite or possible endocarditis by modified Duke criteria was found in 74 patients: 20 patients were IDUs and 54 nonaddicts. RESULTS: Endocarditis was more common in SAB among drug abusers (46%) than in nonaddicts (14%) (odds ratio [OR], 5.12; 95% confidence interval [CI], 2.65–9.91; P < 0.001). IDUs were significantly younger (27 ± 15 vs 65 ± 15 years, P < 0.001), had less ultimately or rapidly fatal underlying diseases (0% vs 37%, P < 0.001) or predisposing heart diseases (20% vs 50%, P = 0.03), and their SAB was more often community-acquired (95% vs 39%, P < 0.001). Right-sided endocarditis was observed in 60% of IDUs whereas 93% of nonaddicts had left-sided involvement (P < 0.001). An extracardiac deep infection was found in 85% of IDUs and in 89% of nonaddicts (P = 0.70). Arterial thromboembolic events and severe sepsis were also equally common in both groups. There was no difference in mortality between the groups at 7 days, but at 3 months it was lower among IDUs (10%) compared with nonaddicts (39%) (OR, 5.73; 95% CI, 1.20–27.25; P = 0.02). CONCLUSION: S. aureus endocarditis in IDUs was associated with as high complication rates including extracardiac deep infections, thromboembolic events, or severe sepsis as in nonaddicts. Injection drug abuse in accordance with younger age and lack of underlying diseases were associated with lower mortality, but after adjusting by age and underlying diseases injection drug abuse was not significantly associated with mortality
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