scholarly journals Statistical Methods for Evaluating DNA Methylation as a Marker for Early Detection or Prognosis

2007 ◽  
Vol 23 (1-2) ◽  
pp. 113-120 ◽  
Author(s):  
Todd A. Alonzo ◽  
Kimberly D. Siegmund
Keyword(s):  
Dna Methylation ◽  
Statistical Methods ◽  
False Positive ◽  
Classification Accuracy ◽  
Error Rates ◽  
True Positive ◽  
Time To Death ◽  
Methylation Marker ◽  
Positive Fraction ◽  
Time Invariant

We summarize standard and novel statistical methods for evaluating the classification accuracy of DNA methylation markers. The choice of method will depend on the type of marker studied (qualitative/quantitative), the number of markers, and the type of outcome (time-invariant/time-varying). A minimum of two error rates are needed for assessing marker accuracy: the true-positive fraction and the false-positive fraction. Measures of association that are computed from the combination of these error rates, such as the odds ratio or relative risk, are not informative about classification accuracy. We provide an example of a DNA methylation marker that is strongly associated with time to death (logrankp= 0.0003) that is not a good classifier as evaluated by the true-positive and false-positive fractions. Finally, we would like to emphasize the importance of study design. Markers can behave differently in different groups of individuals. It is important to know what factors may affect the accuracy of a marker and in which subpopulations the marker may be more accurate. Such an understanding is extremely important when comparing marker accuracy in two groups of subjects.

scholarly journals Ensemble of Rule Learner and Sequential Minimum Optimization Algorithm for Intrusion Detection System

2019 ◽  
Vol 9 (2) ◽  
pp. 501-506
Keyword(s):  
Machine Learning ◽  
Intrusion Detection ◽  
Decision Tree ◽  
Optimization Algorithm ◽  
False Positive ◽  
Classification Accuracy ◽  
Intrusion Detection System ◽  
Detection System ◽  
Support Vector ◽  
True Positive

An intrusion detection system is a process which automates analyzing activities in network or a computer system. It is used to detect nasty code, hateful activities, intruders and uninvited communications over the Internet. The general intrusion detection system is struggling with some problems like false positive rate, false negative rate, low classification accuracy and slow speed. Now-a-days, this has turned an attention of many researchers to handle these issues. Recently, ensemble of different base classifier is widely used to implement intrusion detection system. In ensemble method of machine learning, the proper selection of base classifier is a challenging task. In this paper, machine learning ensemble have designed and implemented for the intrusion detection system. The ensemble of Partial Decision Tree and Sequential Minimum optimization algorithm to train support vector machine have used for intrusion detection system. Partial Decision Tree rule learner is simplicity and it generates rules fast. Sequential Minimum optimization algorithm is easy to use and is better scaling with training set size with less computational time. Due to these advantages of both classifiers, they jointly used with different methods of ensemble. We make use of all types of methods of ensemble. The performances of base classifiers have evaluated in term of false positive, accuracy and true positive. Performance results display that proposed majority voting method of ensemble using Partial Decision Tree rule learner and Sequential Minimum optimization algorithm based Support Vector Machine offers highest classification among different ensemble classifiers on training dataset. This method of ensemble exhibits highest true positive and lowest false positive rates. It is also observed that stacking of both PART and SMO exhibits lowest and same classification accuracy on test dataset.

Forensic science evidence: Naive estimates of false positive error rates and reliability

2020 ◽  
Author(s):  
Kristy Martire ◽  
Agnes Bali ◽  
Kaye Ballantyne ◽  
Gary Edmond ◽  
Richard Kemp ◽  
...  
Keyword(s):  
Forensic Science ◽  
False Positive ◽  
Error Rates ◽  
Forensic Sciences ◽  
Positive Error ◽  
False Positive Error ◽  
Reliability Estimates ◽  
Positive Report ◽  
Science Evidence ◽  
Science Disciplines

We do not know how often false positive reports are made in a range of forensic science disciplines. In the absence of this information it is important to understand the naive beliefs held by potential jurors about forensic science evidence reliability. It is these beliefs that will shape evaluations at trial. This descriptive study adds to our knowledge about naive beliefs by: 1) measuring jury-eligible (lay) perceptions of reliability for the largest range of forensic science disciplines to date, over three waves of data collection between 2011 and 2016 (n = 674); 2) calibrating reliability ratings with false positive report estimates; and 3) comparing lay reliability estimates with those of an opportunity sample of forensic practitioners (n = 53). Overall the data suggest that both jury-eligible participants and practitioners consider forensic evidence highly reliable. When compared to best or plausible estimates of reliability and error in the forensic sciences these views appear to overestimate reliability and underestimate the frequency of false positive errors. This result highlights the importance of collecting and disseminating empirically derived estimates of false positive error rates to ensure that practitioners and potential jurors have a realistic impression of the value of forensic science evidence.

scholarly journals PRATD: A Phased Remote Access Trojan Detection Method with Double-Sided Features

Electronics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1894
Author(s):  
Chun Guo ◽  
Zihua Song ◽  
Yuan Ping ◽  
Guowei Shen ◽  
Yuhei Cui ◽  
...  
Keyword(s):  
False Positive ◽  
Detection Method ◽  
False Positive Rate ◽  
True Positive Rate ◽  
Remote Access ◽  
Detection Methods ◽  
Security Threats ◽  
True Positive ◽  
Trojan Detection ◽  
Positive Rate

Remote Access Trojan (RAT) is one of the most terrible security threats that organizations face today. At present, two major RAT detection methods are host-based and network-based detection methods. To complement one another’s strengths, this article proposes a phased RATs detection method by combining double-side features (PRATD). In PRATD, both host-side and network-side features are combined to build detection models, which is conducive to distinguishing the RATs from benign programs because that the RATs not only generate traffic on the network but also leave traces on the host at run time. Besides, PRATD trains two different detection models for the two runtime states of RATs for improving the True Positive Rate (TPR). The experiments on the network and host records collected from five kinds of benign programs and 20 famous RATs show that PRATD can effectively detect RATs, it can achieve a TPR as high as 93.609% with a False Positive Rate (FPR) as low as 0.407% for the known RATs, a TPR 81.928% and FPR 0.185% for the unknown RATs, which suggests it is a competitive candidate for RAT detection.

Design Issues of Randomized Phase II Trials and a Proposal for Phase II Screening Trials

2005 ◽  
Vol 23 (28) ◽  
pp. 7199-7206 ◽  
Author(s):  
Lawrence V. Rubinstein ◽  
Edward L. Korn ◽  
Boris Freidlin ◽  
Sally Hunsberger ◽  
S. Percy Ivy ◽  
...  
Keyword(s):  
Phase Ii ◽  
False Positive ◽  
Standard Treatment ◽  
False Negative ◽  
Error Rates ◽  
Targeted Treatment ◽  
Phase Iii ◽  
Phase Ii Trials ◽  
Treatment Control ◽  
Randomized Phase Ii

Future progress in improving cancer therapy can be expedited by better prioritization of new treatments for phase III evaluation. Historically, phase II trials have been key components in the prioritization process. There has been a long-standing interest in using phase II trials with randomization against a standard-treatment control arm or an additional experimental arm to provide greater assurance than afforded by comparison to historic controls that the new agent or regimen is promising and warrants further evaluation. Relevant trial designs that have been developed and utilized include phase II selection designs, randomized phase II designs that include a reference standard-treatment control arm, and phase II/III designs. We present our own explorations into the possibilities of developing “phase II screening trials,” in which preliminary and nondefinitive randomized comparisons of experimental regimens to standard treatments are made (preferably using an intermediate end point) by carefully adjusting the false-positive error rates (α or type I error) and false-negative error rates (β or type II error), so that the targeted treatment benefit may be appropriate while the sample size remains restricted. If the ability to conduct a definitive phase III trial can be protected, and if investigators feel that by judicious choice of false-positive probability and false-negative probability and magnitude of targeted treatment effect they can appropriately balance the conflicting demands of screening out useless regimens versus reliably detecting useful ones, the phase II screening trial design may be appropriate to apply.

scholarly journals Evolution of case fatality rates in the second wave of coronavirus in England: effects of false positives, a Variant of Concern and vaccination.

2021 ◽  
Author(s):  
James A Ackland ◽  
Graeme J Ackland ◽  
David J Wallace
Keyword(s):  
False Positive ◽  
Age Groups ◽  
Case Fatality ◽  
Potential Effect ◽  
Time To Death ◽  
New Variant ◽  
Government Data ◽  
The Uk ◽  
Second Wave ◽  
Over Time

Objective: To track the statistical case fatality rate (CFR) in the second wave of the UK coronavirus outbreak, and to understand its variations over time. Design: Publicly available UK government data and clinical evidence on the time between first positive PCR test and death are used to determine the relationships between reported cases and deaths, according to age groups and across regions in England. Main Outcome Measures: Estimates of case fatality rates and their variations over time. Results: Throughout October and November 2020, deaths in England can be broadly understood in terms of CFRs which are approximately constant over time. The same CFRs prove a poor predictor of deaths when applied back to September, when prevalence of the virus was comparatively low, suggesting that the potential effect of false positive tests needs to be taken into account. Similarly, increasing CFRs are needed to match cases to deaths when projecting the model forwards into December. The growth of the S gene dropout VOC in December occurs too late to explain this increase in CFR alone, but at 33% increased mortality, it can explain the peak in deaths in January. On our analysis, if there were other factors responsible for the higher CFRs in December and January, 33% would be an upper bound for the higher mortality of the VOC. From the second half of January, the CFRs for older age groups show a marked decline. Since the fraction of the VOC has not decreased, this decline is likely to be the result of the rollout of vaccination. However, due to the rapidly decreasing nature of the raw cases data (likely due to a combination of vaccination and lockdown), any imprecisions in the time-to-death distribution are greatly exacerbated in this time period, rendering estimates of vaccination effect imprecise. Conclusions: The relationship between cases and deaths, even when controlling for age, is not static through the second wave of coronavirus in England. An apparently anomalous low case-fatality ratio in September can be accounted for by a modest 0.4% false-positive fraction. The large jump in CFR in December can be understood in terms of a more deadly new variant B1.1.7, while a decline in January correlates with vaccine roll-out, suggesting that vaccine reduce the severity of infection, as well as the risk.

scholarly journals Coupling Uncertainties with Accuracy Assessment in Object-based Slum Detections, Case Study: Jakarta, Indonesia

2017 ◽  
Author(s):  
Jati Pratomo ◽  
Monika Kuffer ◽  
Javier Martinez ◽  
Divyani Kohli
Keyword(s):  
Land Tenure ◽  
Classification Accuracy ◽  
Accuracy Assessment ◽  
False Negative ◽  
National Policy ◽  
True Positive ◽  
True Negative ◽  
Object Based ◽  
The Impact

Object-Based Image Analysis (OBIA) has been successfully used to map slums. In general, the occurrence of uncertainties in producing geographic data is inevitable. However, most studies concentrated solely on assessing the classification accuracy and neglecting the inherent uncertainties. Our research analyses the impact of uncertainties in measuring the accuracy of OBIA-based slum detection. We selected Jakarta as our case study area, because of a national policy of slum eradication, which is causing rapid changes in slum areas. Our research comprises of four parts: slum conceptualization, ruleset development, implementation, and accuracy and uncertainty measurements. Existential and extensional uncertainty arise when producing reference data. The comparison of a manual expert delineations of slums with OBIA slum classification results into four combinations: True Positive, False Positive, True Negative and False Negative. However, the higher the True Positive (which lead to a better accuracy), the lower the certainty of the results. This demonstrates the impact of extensional uncertainties. Our study also demonstrates the role of non-observable indicators (i.e., land tenure), to assist slum detection, particularly in areas where uncertainties exist. In conclusion, uncertainties are increasing when aiming to achieve a higher classification accuracy by matching manual delineation and OBIA classification.

Error Rates in Competency Testing When Test Retaking Is Permitted

1990 ◽  
Vol 15 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Huynh Huynh
Keyword(s):  
Conditional Probability ◽  
False Positive ◽  
False Negative ◽  
Error Rates ◽  
Rasch Models ◽  
Positive Error ◽  
False Positive Error ◽  
Competency Testing ◽  
Negative Error ◽  
False Negative Error

False positive and false negative error rates are studied for competency testing where examinees are permitted to retake the test if they fail to pass. Formulae are provided for the beta-binomial and Rasch models, and estimates based on these two models are compared for several typical situations. Although Rasch estimates are expected to be more accurate than beta-binomial estimates, differences among them are found not to be substantial in a number of practical situations. Under relatively general conditions and when test retaking is permitted, the probability of making a false negative error is zero. Under the same situation, and given that an examinee is a true nonmaster, the conditional probability of making a false positive error for this examinee is one.

scholarly journals A HMM-R Approach to Detect L-DDoS Attack Adaptively on SDN Controller

2018 ◽  
Vol 10 (9) ◽  
pp. 83 ◽  
Author(s):  
Wentao Wang ◽  
Xuan Ke ◽  
Lingxia Wang
Keyword(s):  
Data Center ◽  
False Positive ◽  
Data Flow ◽  
Denial Of Service ◽  
True Positive ◽  
Ddos Attacks ◽  
Data Center Network ◽  
Data Packets ◽  
Positive Rate ◽  
Sdn Controller

A data center network is vulnerable to suffer from concealed low-rate distributed denial of service (L-DDoS) attacks because its data flow has the characteristics of data flow delay, diversity, and synchronization. Several studies have proposed addressing the detection of L-DDoS attacks, most of them are only detect L-DDoS attacks at a fixed rate. These methods cause low true positive and high false positive in detecting multi-rate L-DDoS attacks. Software defined network (SDN) is a new network architecture that can centrally control the network. We use an SDN controller to collect and analyze data packets entering the data center network and calculate the Renyi entropies base on IP of data packets, and then combine them with the hidden Markov model to get a probability model HMM-R to detect L-DDoS attacks at different rates. Compared with the four common attack detection algorithms (KNN, SVM, SOM, BP), HMM-R is superior to them in terms of the true positive rate, the false positive rate, and the adaptivity.

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