Optimal anonymous location privacy protection algorithm based on grid user density

ABSTRACT

The existing location anonymity algorithms do not consider the distribution of user density in the region. The area of anonymous domain is not the most appropriate and the query workload is redundant. To solve this problem, this paper proposes optimal anonymous location privacy protection algorithm based on grid user density. Taking the user density of the regional grid as the core and using reasonable dynamic shrinkage and expansion rules to find the most suitable anonymous domain, and reduces the anonymous domain as much as possible to meet the user privacy parameter configuration, thereby improving LBS service quality. This paper builds simulation dataset based on road network moving objects, and simulation experiments are performed on location privacy protection method, which proves the effectiveness of this method. At the same time, the real road network floating vehicle data is selected for the application of algorithm, which proves the feasibility of this method.     

超声波流量计在天然气计量中的故障诊断研究

针对超声波流量计在川气东送管道天然气计量中的应用,通过分析超声波流量计的工作原理,结合现场应用,对常见的超声波流量计故障及计量误差问题进行总结,指出在超声波流量计应用中应注意的维护工作要点,从而降低超声波流量计的测量误差,保证贸易计量的公平公正性。     

The Weibull log-logistic mixture distributions: Model,theory and application to lifetime data

Lifetime data collected from reliability tests are among data that often exhibit significant heterogeneity caused by variations in manufacturing, which makes standard lifetime models inadequate. Finite mixture models provide more flexibility for modeling such data. In this paper, the Weibull-log-logistic mixture distributions model is introduced as a new class of flexible models for heterogeneous lifetime data. Some statistical properties of the model are presented including the failure rate function, moments generating function, and characteristic function. The identifiability property of the class of all finite mixtures of Weibull-log-logistic distributions is proved. The maximum likelihood estimation (MLE) of model parameters under the Type I and Type II censoring schemes is derived. Some numerical illustrations are performed to study the behavior of the obtained estimators. The model is applied to the hard drive failure data made by the Backblaze data center, where it is found that the proposed model provides more flexibility than the univariate life distributions (Weibull, Exponential, logistic, log-logistic, Frechet). The failure rate of hard disk drives (HDDs) is obtained based on MLE estimates. The analysis of the failure rate function on the basis of SMART attributes shows that the failure of HDDs can have different causes and mechanisms.     

Crash avoidance in response to challenging driving events: The roles of age,serialization, and driving simulator platform

We examined the crash avoidance behaviors of older and middle-aged drivers in reaction to six simulated challenging road events using two different driving simulator platforms. Thirty-five healthy adults aged 21–36 years old (M = 28.9 ± 3.96) and 35 healthy adults aged 65–83 years old (M = 72.1 ± 4.34) were tested using a mid-level simulator, and 27 adults aged 21–38 years old (M = 28.6 ± 6.63) and 27 healthy adults aged 65–83 years old (M = 72.7 ± 5.39) were tested on a low-cost desktop simulator. Participants completed a set of six challenging events varying in terms of the maneuvers required, avoiding space given, directional avoidance cues, and time pressure. Results indicated that older drivers showed higher crash risk when events required multiple synchronized reactions. In situations that required simultaneous use of steering and braking, older adults tended to crash significantly more frequently. As for middle-aged drivers, their crashes were attributable to faster driving speed. The same age-related driving patterns were observed across simulator platforms. Our findings support the hypothesis that older adults tend to react serially while engaging in cognitively challenging road maneuvers.     

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (<27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.     

The effect of pallet connection stiffness,deck stiffness and static load level on the resonant response of pallet decks to vibration frequencies occurring in the distribution environment

This paper summarizes the results of a preliminary study of the relationship between pallet design and the resonant response of pallet decks to sinusoidal vibration. Sine sweep frequency vibration tests between 3 Hz and 50 Hz were conducted to determine the effect of pallet deckboard stiffness, joint stiffness and the static load level on the resonant response of pallet decks. As the stiffness of the pallet joints and deckboards increases, the resonant frequency of the unit load increases and transmissibility decreases. As the static load on the pallet increases the resonant frequency of the unit load decreases and the transmissibility increases. The survivability of a unitized product, sensitive to vibration, during shipping and distribution is affected by the pallet design. Pallets designed using rigid connections and stiffer decks will reduce damage to vibration‐sensitive products. Copyright © 1999 John Wiley & Sons, Ltd.