Reliability evaluation of a multicast over coded packet networks

Network coding is a generalization of conventional routing methods that allows a network node to code information flows before forwarding them. While it has been theoretically proved that network coding can achieve maximum network throughput, theoretical results usually do not consider the stochastic nature in information processing and transmission, especially when the capacity of each arc becomes stochastic due to failure, attacks, or maintenance. Hence, the reliability measurement of network coding becomes an important issue to evaluate the performance of the network under various system settings. In this paper, we present analytical expressions to measure the reliability of multicast communications in coded networks, where network coding is most promising. We define the probability that a multicast rate can be transmitted through a coded packet network under a total transmission cost constraint as the reliability metric. To do this, we first introduce an exact mathematical formulation to construct multicast connections over coded packet networks under a limited transmission cost. We then propose an algorithm based on minimal paths to calculate the reliability measurement of multicast connections and analyze the complexity of the algorithm. Our results show that the reliability of multicast routing with network coding improved significantly compared to the case of multicast routing without network coding.     

Knox meets Cox: Adapting epidemiological space-time statistics to demographic studies

Many important questions and theories in demography focus on changes over time, and on how those changes differ over geographic and social space. Space-time analysis has always been important in studying fertility transitions, for example. However, demographers have seldom used formal statistical methods to describe and analyze time series of maps. One formal method, used widely in epidemiology, criminology, and public health, is Knox’s space-time interaction test. In this article, we discuss the potential of the Knox test in demographic research and note some possible pitfalls. We demonstrate how to use familiar proportional hazards models to adapt the Knox test for demographic applications. These adaptations allow for nonrepeatable events and for the incorporation of structural variables that change in space and time. We apply the modified test to data on the onset of fertility decline in Brazil over 1960–2000 and show how the modified method can produce maps indicating where and when diffusion effects seem strongest, net of covariate effects.     

Arts and the Perceived Quality of Life in British Columbia

The aims of this investigation were (1) to measure the impact of arts-related activities on the perceived quality of life of a representative sample of British Columbians aged 18 years or more in the spring of 2007, and (2) to compare the findings of this study with those of a sample of 1,027 adults drawn from five B.C. communities (Comox Valley, Kamloops, Nanaimo, Port Moody and Prince George) in the fall of 2006. Seven hundred and eight British Columbians responded to a mailed out questionnaire, and the working data set was weighted by age and education to match the 2006 census statistics for the province, yielding a fairly representative sample. Speaking quite generally, about 62.0% of the results for the two samples are very similar. In particular, in both surveys we found that (a) among arts-related activities in which people participate relatively infrequently (i.e., participation is counted in times per year rather than in hours per week), live theatre is supreme in the strength of its positive correlation with respondents’ perceived quality of life measured in 7 different ways, and (b) compared to 4 demographic variables (age, education, household income and body mass index), household income had the highest average, positive correlation with 7 different measures of respondents’ overall life assessments, namely, self-assessed general health, satisfaction with life as a whole (single item), happiness, satisfaction with the quality of life, satisfaction with life as a whole (5-item index), contentment with life (5-item index) and subjective wellbeing (4-item index). Different results were found in the province-wide versus the five-communities survey for the following, among other things, (a) compared to all 7 life assessment measures, for the province, satisfaction with the quality of life and happiness had the largest number of significant correlations with arts-related activities measured in hours per week engaged, while for the five communities, the single measure of satisfaction with the quality of life had the largest number of significant correlations, and (b) For the province, compared to all 7 life assessment measures, satisfaction with the quality of life had the largest number of significant correlations with arts-related activities measured in times per year engaged; for the five communities, compared to all 7 life assessment measures, self-assessed general health had the largest number of significant correlations with arts-related activities measured in times per year engaged.     

Population and pavement: population growth and land development in Israel

This research examines land use change in Israel––an intriguing but understudied setting with regard to population–environment dynamics. While Israel is fairly unique with regard to its combined high levels of economic prosperity and high population growth, this case study has relevance for developed countries and regions (like the south and southwest regions of the USA) which must balance population growth and urban development with open space conservation for ecosystem services and biological diversity. The population–land development relationship is investigated during the period from 1961 to 1995 at three spatial scales: national, regional (six districts), and local (40 localities). There is a positive correlation between population growth and land development rates at the national scale, and while remaining positive, the strength of the relationship varies greatly at regional and local scales. The variation in population–land use dynamics across scales is used to garner insight as to the importance of geography, policy and historical settlement patterns.     

Sexuality Examined Through the Lens of Attachment Theory: Attachment,Caregiving, and Sexual Satisfaction

Attachment researchers have proposed that the attachment, caregiving, and sexual behavioral systems are interrelated in adult love relationships (Mikulincer &; Shaver, 2007 Mikulincer , M. , &; Shaver , P. R. ( 2007 ). Attachment in adulthood: Structure, dynamics, and change . New York , NY : Guilford . [Google Scholar]). This study examined whether aspects of partners’ caregiving (proximity, sensitivity, control, compulsive caregiving) mediated the association between their attachment insecurities (anxiety and avoidance) and each other's sexual satisfaction in two samples of committed couples (Study 1: 126 cohabiting or married couples from the general community; Study 2: 55 clinically distressed couples). Partners completed the Experiences in Close Relationships measure (Brennan, Clark, &; Shaver, 1998 Brennan , K. A. , Clark , C. L. , &; Shaver , P. R. ( 1998 ). Self-report measurement of adult attachment: An integrative overview . In J. A. Simpson &; W. W. Rholes (Eds.), Attachment theory and close relationships (pp. 46 – 76 ). New York : Guilford .[Crossref] , [Google Scholar]), the Caregiving Questionnaire (Kunce &; Shaver, 1994 Kunce , L. J. , &; Shaver , P. R. ( 1994 ). An attachment-theoretical approach to caregiving in romantic relationships . In K. Bartholomew &; D. Perlman (Eds.), Advances in personal relationships (pp. 205 – 237 ). London : Kingsley . [Google Scholar]), and the Global Measure of Sexual Satisfaction (Lawrance &; Byers, 1998 Lawrance , K. , &; Byers , E. S. ( 1998 ). Interpersonal Exchange Model of Sexual Satisfaction Questionnaire . In C. M. Davis , W. L. Yarber , R. Bauserman , G. Schreer &; S. L. Davis (Eds.), Sexuality-related measures: A compendium (pp. 514 – 519 ). Thousand Oaks , CA : Sage . [Google Scholar]). Path analyses based on the actor-partner interdependence model (APIM) revealed that caregiving proximity mediated the association between low attachment avoidance and partners’ sexual satisfaction in distressed and nondistressed couples. Sensitivity mediated this association in nondistressed couples only. Control mediated the association between men's insecurities (attachment-related avoidance and anxiety) and their partners’ low sexual satisfaction in nondistressed couples. Attachment anxiety predicted compulsive caregiving, but this caregiving dimension was not a significant mediator. These results are discussed in light of attachment theory and their implications for treating distressed couples.     

Ambivalence in Older Parent–Adult Child Relationships: Mixed Feelings,Mixed Measures

This research compared direct and indirect measures of ambivalence, 2 commonly used strategies for measuring intergenerational ambivalence between older parents and their adult children. Directly and indirectly measured ambivalence, corresponding to felt and potential manifestations of the construct, were contrasted with each other and across generations. Data were derived from 253 older parent–adult child dyads participating in the Longitudinal Study of Generations in 2005. Direct and indirect measures of ambivalence were moderately correlated with each other within each generation. Children expressed greater indirect ambivalence than their parents but were no different than their mothers or fathers in their levels of direct ambivalence. Multivariate regression analyses examining the relationship between each type of ambivalence with individual and relationship characteristics found differences in associations across equations. The results suggest that direct and indirect measures are related but represent 2 distinct conceptions of ambivalence. This research highlights the challenges in understanding the full complexity of intergenerational relations and suggests that both generational perspectives be considered in future research.     

Sexual Hookups and Adverse Health Outcomes: A Longitudinal Study of First-Year College Women

“Hookups” are sexual encounters between partners who are not in a romantic relationship and do not expect commitment. We examined the associations between sexual hookup behavior and depression, sexual victimization (SV), and sexually transmitted infections (STIs) among first-year college women. In this longitudinal study, 483 women completed 13 monthly surveys assessing oral and vaginal sex with hookup and romantic partners, depression, SV, and self-reported STIs. Participants also provided biological specimens that were tested for STIs. During the study, 50% of participants reported hookup sex and 62% reported romantic sex. Covariates included previous levels of the outcome, alcohol use, impulsivity, sensation seeking, and romantic sex. Autoregressive cross-lagged models showed that, controlling for covariates, hookup behavior during college was correlated with depression, Bs = .21, ps < .05, and SV, Bs = .19, ps < .05. In addition, precollege hookup behavior predicted SV early in college, B = .62, p < .05. Hookup sex, OR 1.32, p < .05, and romantic sex, OR 1.19, p < .05, were associated with STIs. Overall, sexual hookup behavior among college women was positively correlated with experiencing depression, SV, and STIs, but the nature of these associations remains unclear, and hooking up did not predict future depression.     

A Psychometric Comparison of Three Scales and a Single-Item Measure to Assess Sexual Satisfaction

This study was designed to systematically compare and contrast the psychometric properties of three scales developed to measure sexual satisfaction and a single-item measure of sexual satisfaction. The Index of Sexual Satisfaction (ISS), Global Measure of Sexual Satisfaction (GMSEX), and the New Sexual Satisfaction Scale–Short (NSSS-S) were compared to one another and to a single-item measure of sexual satisfaction. Conceptualization of the constructs, distribution of scores, internal consistency, convergent validity, test-retest reliability, and factor structure were compared between the measures. A total of 211 men and 214 women completed the scales and a measure of relationship satisfaction, with 33% (n = 139) of the sample reassessed two months later. All scales demonstrated appropriate distribution of scores and adequate internal consistency. The GMSEX, NSSS-S, and the single-item measure demonstrated convergent validity. Test-retest reliability was demonstrated by the ISS, GMSEX, and NSSS-S, but not the single-item measure. Taken together, the GMSEX received the strongest psychometric support in this sample for a unidimensional measure of sexual satisfaction and the NSSS-S received the strongest psychometric support in this sample for a bidimensional measure of sexual satisfaction.     

Do Alcohol and Marijuana Use Decrease the Probability of Condom Use for College Women?

Alcohol and marijuana use are thought to increase sexual risk taking, but event-level studies conflict in their findings and often depend on reports from a limited number of people or on a limited number of sexual events per person. With event-level data from 1,856 sexual intercourse events provided by 297 college women (M _age = 18 years; 71% White), we used multilevel modeling to examine associations between alcohol and marijuana use and condom use as well as interactions involving sexual partner type and alcohol-sexual risk expectancies. Controlling for alternative contraception use, partner type, regular levels of substance use, impulsivity and sensation seeking, and demographics, women were no more or less likely to use condoms during events involving drinking or heavy episodic drinking than during those without drinking. However, for drinking events, there was a negative association between number of drinks consumed and condom use; in addition, women with stronger alcohol-sexual risk expectancies were marginally less likely to use condoms when drinking. Although there was no main effect of marijuana use on condom use, these data suggest marijuana use with established romantic partners may increase risk of unprotected sex. Intervention efforts should target expectancies and emphasize the dose-response relationship of drinks to condom use.     

Implementation of Jefferson-d’Hondt rule in the formation of a parliamentary committee

Same parliaments, to form a committee of size $q$ , use a voting process like the following: every parliamentary member votes for one out of a fixed set of candidates, and those $q$ candidates receiving more votes are elected for the committee. Assuming total discipline of vote, this is a game form in which players are the parliamentary groups. We investigate, according to some natural hypotheses about preferences, the likely distribution of the members of this committee. The main results are: (a) when fractional votes are allowed, there is a complete agreement between the distribution among the groups of the elected candidates that are outcomes of a Nash equilibrium and the distribution that, according to the size of the groups, would compute the Jefferson-d’Hondt allocation rule, and (b) when fractional votes are not allowed, there is a near agreement for a majority of situations.