Key predistribution scheme using finite fields and reed muller codes

Resource constraint sensors of a Wireless Sensor Network (WSN) cannot afford the use of costly encryption techniques like public key while dealing with sensitive data. So symmetric key encryption techniques are preferred where it is essential to have the same cryptographic key between communicating parties. To this end, keys are preloaded into the nodes before deployment and are to be established once they get deployed in the target area. This entire process is called key predistribution. In this paper we propose one such scheme using unique factorization of polynomials over Finite Fields. To the best of our knowledge such an elegant use of Algebra is being done for the first time in WSN literature. The best part of the scheme is large number of node support with very small and uniform key ring per node. However the resiliency is not good. For this reason we use a special technique based on Reed Muller codes proposed recently by Sarkar, Saha and Chowdhury in 2010. The combined scheme has good resiliency with huge node support using very less keys per node.

Detection of curved edges at subpixel accuracy using deformable models

One approach to the detection of curves at subpixel accuracy involves the reconstruction of such features from subpixel edge data points. A new technique is presented for reconstructing and segmenting curves with subpixel accuracy using deformable models. A curve is represented as a set of interconnected Hermite splines forming a snake generated from the subpixel edge information that minimizes the global energy functional integral over the set. While previous work on the minimization was mostly based on the Euler-Lagrange transformation, the authors use the finite element method to solve the energy minimization equation. The advantages of this approach over the Euler-Lagrange transformation approach are that the method is straightforward, leads to positive m-diagonal symmetric matrices, and has the ability to cope with irregular geometries such as junctions and corners. The energy functional integral solved using this method can also be used to segment the features by searching for the location of the maxima of the first derivative of the energy over the elementary curve set.

Direct method for optimal power management in hybrid electric vehicles

Hybrid electric vehicles are powered by an electric system and an internal combustion engine. The components of a hybrid electric vehicle need to be coordinated in an optimal manner to deliver the desired performance. This paper presents an approach based on direct method for optimal power management in hybrid electric vehicles with inequality constraints. The approach consists of reducing the optimal control problem to a set of algebraic equations by approximating the state variable which is the energy of electric storage, and the control variable which is the power of fuel consumption. This approximation uses orthogonal functions with unknown coefficients. In addition, the inequality constraints are converted to equal constraints. The advantage of the developed method is that its computational complexity is less than that of dynamic and non-linear programming approaches. Also, to use dynamic or non-linear programming, the problem should be discretized resulting in the loss of optimization accuracy. The propsed method, on the other hand, does not require the discretization of the problem producing more accurate results. An example is solved to demonstrate the accuracy of the proposed approach. The results of Haar wavelets, and Chebyshev and Legendre polynomials are presented and discussed. © 2011 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.

Clinical and economic burden of emergency department presentations for neutropenia following outpatient chemotherapy for cancer in Victoria, Australia

Objective. To examine the clinical characteristics and financial charges associated with treating adult cancer patients receiving chemotherapy in outpatient clinics who presented to the emergency department (ED) with neutropenia.
Design and Setting. A retrospective audit was conducted across two health services involving ED episodes and subsequent hospital admissions of patients who received chemotherapy through day oncology from January 1 to December 31, 2007 and presented to the ED with neutropenia. ED data were collected from the Victorian Emergency Minimum Dataset and charges were collected from Health Information Services. Descriptive and bivariate statistics were used to describe the patient and clinical characteristics and financial outcomes, and to explore associations between these factors.
Results. In total, 200 neutropenic episodes in 159 outpatients were seen in the ED over the survey period. The mean patient age was 56.6 years (standard deviation, 13.2 years) and 47.2% were male. Overall, 70.0% of ED episodes were triaged as Australasian Triage Scale 2 (emergency). The median ED wait time was 10 minutes and the median ED length of stay was 6.8 hours. The median charge for each ED episode was $764.08 Australian dollars. The total combined ED and inpatient charge per episode was in the range of $144.27-$174,732.68, with a median charge of $5,640.87.
Conclusions. This study provides important insights into the clinical and economic burden of neutropenia from both the ED and inpatient perspectives. Alternative treatment models, such as outpatient treatment, early discharge programs or prophylactic interventions to reduce the clinical and economic burden of neutropenia on our health system, must be explored.

Physical activity participation and barriers for people with multiple myeloma

Purpose

This study aims to examine, for people treated for multiple myeloma, (1) differences between prediagnosis and postdiagnosis levels of physical activity, (2) perceived barriers and likelihood of attending a physical activity program, and (3) factors that influence whether or not respondents are meeting physical activity guidelines.
Methods

This was a quantitative cross-sectional study; data were gathered from a larger Australian population-wide survey. Respondents completed the survey in hard copy, online, or over the telephone. Demographic and clinical variables included age, gender, locality, time since diagnosis, and marital status. The Godin Leisure-Time Questionnaire measured physical activity; barriers and likelihood of participating in a physical activity program were assessed using a five-point Likert scale. Data were analyzed using descriptive, bivariate, and multivariate analyses.
Results

Of the 229 respondents, 53.1 % were male, 42 % aged 60–69 years, and 75.7 % were married or in a de facto relationship. Participation in physical activity declined significantly from prediagnosis levels. Fatigue, injuries, and pain were the strongest perceived barriers to participation; 41 % reported they were likely to attend an exercise program if offered. Respondents who were sufficiently active before diagnosis were 4.79 times more likely to be sufficiently active posttreatment.
Conclusions

People with multiple myeloma reported very low levels of physical activity across all levels of intensity; however, they were interested in attending a physical activity program. To increase physical activity among people with multiple myeloma, interventions should target perceived barriers with a particular focus on those who were not physically active prior to diagnosis.

Analyzing track sprint cyclists' performances using position-specific maximal-torque and power-cadence relationships

Previous studies have demonstrated the importance of maximal Torque-Cadence (T-C) and Power-Cadence (P-C) relationships, for the performances of world class track sprint cyclists. If these relationships are affected by the function of the lower limb muscles, the ability of cyclists to generate torque and power at a given cadence may vary depending on their riding position. During sprint events (individual and team sprints and Keirin), cyclists alternate between standing and seated positions. The T-C and P-C relationships may change with the position adopted by the cyclists. PURPOSE: The aim of this study was to evaluate the necessity to define position specific maximal T-C and P-C relationships. METHODS: Eight junior elite track cyclists from the National Talent Identification squad undertook two inertial-load tests that consisted of four all-out sprints each. One test was undertaken at the velodrome in a standing position on a carbon fibre track bike, and the other test was completed in a seated position on an air-braked stationary ergometer. A calibrated SRM power meter interfaced to a custom instrumentation package was used for all mechanical measurements. Maximal T-C and P-C relationships were analysed to calculate maximal Torque (T0), maximal Power (Pmax) and optimal pedalling cadence (PCopt). RESULTS: All individual T-C and P-C relationships obtained for both body positions were fitted by linear regressions (r2=0.95 ± 0.02) and second order polynomials (r2=0.96 ± 0.01), respectively. T0 was higher (209 ± 2.2N.m vs. 177.0 ± 3.9N.m, p<0.05), PCopt was lower (112.5 ± 11.4rpm vs. 120.1 ± 6.7rpm, p<0.05), and Pmax was higher (1261 ± 235W vs. 1076 ± 183W, p<0.05) in standing position compared to seated position. CONCLUSION: Analysis of track sprint cyclists’ performances can be improved by the determination of position-specific maximal T-C and P-C relationships .

A data mining application of the incidence semirings

This paper is devoted to a combinatorial problem for incidence semirings, which can be viewed as sets of polynomials over graphs, where the edges are the unknowns and the coefficients are taken from a semiring. The construction of incidence rings is very well known and has many useful applications. The present article is devoted to a novel application of the more general incidence semirings. Recent research on data mining has motivated the investigation of the sets of centroids that have largest weights in semiring constructions. These sets are valuable for the design of centroid-based classification systems, or classifiers, as well as for the design of multiple classifiers combining several individual classifiers. Our article gives a complete description of all sets of centroids with the largest weight in incidence semirings.

Polynomial based key predistribution scheme in wireless mesh networks

Wireless mesh networks (WMNs) have the ability to integrate with other networks while providing a fast and cost-saving deployment. The network security is one of important challenge problems in this kind of networks. This paper is focused on key management between mesh and sensor networks. We propose an efficient key pre-distribution scheme based on two polynomials in wireless mesh networks by employing the nature of heterogeneity. Our scheme realizes the property of bloom filters, i.e., neighbor nodes can discover their shared keys but have no knowledge on the different keys possessed by the other node, without the probability of false positive. The analysis presented in this paper shows that our scheme has the ability to establish three different security level keys and achieves the property of self adaptive security for sensor networks with acceptable computation and communication consumption.

Environmental invitingness for transport-related cycling in middle-aged adults: a proof of concept study using photographs

Introduction: Current evidence on associations between modifiable environmental characteristics and transport-related cycling remains inconsistent. Most studies on these associations used questionnaires to determine environmental perceptions, but such tools may be subject to bias due to unreliable recall. Moreover, questionnaires only measure separate environmental characteristics, while real environments are a combination of different characteristics. To overcome these limitations, the present proof of concept study used panoramic photographs of cycling environments to capture direct responses to the physical environment. We examined which depicted environmental characteristics were associated to environments' invitingness for transportation cycling. Furthermore, interactions with gender and participants' cycling behavior were examined. Methods: Fifty-nine middle-aged adults were recruited through purposeful convenience sampling. During a home visit, participants took part in a structured interview assessing demographics and PA during the preceding seven days, followed by an intuitive choice task and a (cognitive) rating task, which both measured 40 photographed environments' invitingness to cycle along. Multi-level cross-classified analyses were conducted using MLwiN 2.26. Results: Both tasks' multivariate results showed that presence of vegetation was identified as the most important environmental characteristic to invite people for engaging in transportation cycling, even when the amount of vegetation was relatively small. In the bivariate analyzes, some differences between results of the cognitive rating task and the intuitive choice task were found, showing that invitingness measured by the rating task was associated with environmental maintenance and cycling infrastructure, whereas invitingness determined by the choice task was associated with more traffic-oriented characteristics. Moreover, only for the choice task's results, moderating effects of gender and participants' cycling behavior in the preceding week were observed. Conclusion: The present study provides proof of concept that capturing people's less cognitive, more intuitive responses to an environment's invitingness for transport-related cycling may be important for revealing environment-behavior associations. If replicated in future studies using larger samples, results of our innovative measurements with photographs, especially those on vegetation, can complete the existing knowledge on which environmental characteristics are important for transportation cycling in adults and could form a basis to inform health promoters and local policy makers. However, future studies replicating our study method in larger samples and other population subgroups are highly encouraged. Moreover, causal relationships should be explored.

Effect of ECG-derived respiration (EDR) on modeling ventricular repolarization dynamics in different physiological and psychological conditions

Ventricular repolarization dynamics is an important predictor of the outcome in cardiovascular diseases. Mathematical modeling of the heart rate variability (RR interval variability) and ventricular repolarization variability (QT interval variability) is one of the popular methods to understand the dynamics of ventricular repolarization. Although ECG derived respiration (EDR) was previously suggested as a surrogate of respiration, but the effect of respiratory movement on ventricular repolarization dynamics was not studied. In this study, the importance of considering the effect of respiration and the validity of using EDR as a surrogate of respiration for linear parametric modeling of ventricular repolarization variability is studied in two cases with different physiological and psychological conditions. In the first case study, we used 20 young and 20 old healthy subjects’ ECG and respiration data from Fantasia database at Physionet to analyze a bivariate QT–RR and a trivariate QT–RR–RESP or QT–RR–EDR model structure to study the aging effect on cardiac repolarization variability. In the second study, we used 16 healthy subjects’ data from drivedb (stress detection for automobile drivers) database at Physionet to do the same analysis for different psychological condition (i.e., in stressed and no stress condition). The results of our study showed that model having respiratory information (QT–RR–RESP and QT–RR–EDR) gave significantly better fit value (p < 0.05) than that of found from the QT–RR model. EDR showed statistically similar (p > 0.05) performance as that of respiration as an exogenous model input in describing repolarization variability irrespective of age and different mental conditions. Another finding of our study is that both respiration and EDR-based models can significantly (p < 0.05) differentiate the ventricular repolarization dynamics between healthy subjects of different age groups and with different psychological conditions, whereas models without respiration or EDR cannot distinguish between the groups. These results established the importance of using respiration and the validity of using EDR as a surrogate of respiration in the absence of respiration signal recording in linear parametric modeling of ventricular repolarization variability in healthy subjects.

Self-reported risk-taking behavior during matched-frequency sessions of alcohol versus combined alcohol and energy drinks consumption: Does co-ingestion increase risk-taking?

Background: Emerging evidence indicates that consumers of alcohol mixed with energy drink (AmED) self-report lower odds of risk-taking after consuming AmED versus alcohol alone. However, these studies have been criticized for failing to control for relative frequency of AmED versus alcohol-only consumption sessions. These studies also do not account for quantity of consumption and general alcohol-related risk-taking propensity. The aims of the present study were to (i) compare rates of risk-taking in AmED versus alcohol sessions among consumers with matched frequency of use and (ii) identify consumption and person characteristics associated with risk-taking behavior in AmED sessions. Methods: Data were extracted from 2 Australian community samples and 1 New Zealand community sample of AmED consumers (n = 1,291). One-fifth (21%; n = 273) reported matched frequency of AmED and alcohol use. Results: The majority (55%) of matched-frequency participants consumed AmED and alcohol monthly or less. The matched-frequency sample reported significantly lower odds of engaging in 18 of 25 assessed risk behaviors in AmED versus alcohol sessions. Similar rates of engagement were evident across session type for the remaining behaviors, the majority of which were low prevalence (reported by <15%). Regression modeling indicated that risk-taking in AmED sessions was primarily associated with risk-taking in alcohol sessions, with increased average energy drink (ED) intake associated with certain risk behaviors (e.g., being physically hurt, not using contraception, and driving while over the legal alcohol limit). Conclusions: Bivariate analyses from a matched-frequency sample align with past research showing lower odds of risk-taking behavior after AmED versus alcohol consumption for the same individuals. Multivariate analyses showed that risk-taking in alcohol sessions had the strongest association with risk-taking in AmED sessions. However, hypotheses of increased risk-taking post-AmED consumption were partly supported: Greater ED intake was associated with increased likelihood of specific behaviors, including drink-driving, sexual behavior, and aggressive behaviors in the matched-frequency sample after controlling for alcohol intake and risk-taking in alcohol sessions. These findings highlight the need to consider both personal characteristics and beverage effects in harm reduction strategies for AmED consumers.

Cancer risk factors, diagnosis and sexual identity in the Australian longitudinal study of women's health

PURPOSE: We sought to examine cancer diagnosis, cancer treatment, and related risk factors among Australian, middle-aged, exclusively heterosexual women compared with sexual minority women (SMW; mainly heterosexual, bisexual, mainly lesbian, and lesbian). METHODS: Secondary data analysis of the Australian Longitudinal Study of Women's Health for women born in 1946 through 1951 (n = 10,451) included bivariate tests (i.e., contingency table analyses, independent t tests). RESULTS: SMW did not have significantly higher cancer diagnoses compared with exclusively heterosexual women, although they were more likely to report never having had a mammogram or pap smear. SMW were also significantly more likely to be high-risk drinkers (11.1% vs. 6.8%; p < .05), current smokers (15.1% vs. 8.3%; p < .001), report significantly higher rates of depression (mean ± SD; 6.4 ± 5.5 vs. 5.4 ± 5.1; p < .01.), have experienced physical abuse (10.2% vs. 5.1%; p < .001), and been in a violent relationship (27.2% vs. 12.8%; p < .001). CONCLUSION: SMW had higher rates of several known cancer risk factors, ostensibly placing them at higher risk of cancer as well as chronic health conditions. Further research is needed to determine whether increased risk results in increased cancer as these women age, and to inform the development of interventions to reduce the risk of disease for SMW.

How active are people in metropolitan parks? An observational study of park visitation in Australia

BACKGROUND: Parks are generally an under-utilized resource in the community with great potential to enhance levels of physical activity. If parks are to attract more visitors across a broad cross-section of the population and facilitate increased physical activity, research is needed to better understand park visitor characteristics and how visitors spend their time in parks. The Recording and EValuating Activity in a Modified Park (REVAMP) study is a natural experiment monitoring a park upgrade in a low socioeconomic status (SES) neighborhood. This study described the observed baseline characteristics of park visitors (age, sex) and characteristics of visitation (weekday or weekend day, period of the day) and explored how these characteristics were associated with observed park-based physical activity in two metropolitan parks located Melbourne, Australia. METHODS: Direct observations of park visitors were conducted using a modified version of SOPARC (the System for Observing Play and Recreation in Communities) on four weekdays and four weekend days. During weekdays, observations were conducted every hour from 7:30 am-4:30 pm and on weekend days from 8:30 am-4:30 pm. This equated to a total of 1460 scans across the two parks. Chi-square tests examined bivariate associations between park-based physical activity, and socio-demographic and park visitation characteristics. Logistic regression models examined the odds of being observed engaging in moderate- to vigorous-intensity physical activity relative to lying/sitting/standing according to socio-demographic and park visitation characteristics. RESULTS: In total, 4756 park visitors were observed with the majority visiting on weekend days (87 %) and in the afternoon (41 %). Most visitors (62 %) were lying, sitting or standing, with only 29 % observed engaging in moderate-intensity and 9 % in vigorous-intensity physical activity. Park use differed by time of day, sex, age group, and neighborhood SES. Physical activity was lower for women than men (OR 0.76) and higher among visitors in the high SES area (OR 1.52). CONCLUSIONS: Parks offer substantial opportunities for people of all ages to engage in physical activity; however, this study showed that a large proportion of the park visitors observed were engaged in sedentary pursuits. Further research on how park design, amenities and programming can optimize park visitation and park-based physical activity is needed. TRIAL REGISTRATION: Current controlled trial ISRCTN50745547 , registration date 11.1.2014.