We study the problem of privacy-preservation in social networks. We consider the distributed setting in which the network data is split between several data holders. The goal is to arrive at an anonymized view of the unified network without revealing to any of the data holders information about links between nodes that are controlled by other data holders. To that end, we start withthe centralized setting and offer two variants of an anonymization algorithm which is based on sequential clustering. Our algorithms significantly outperform the SaNGreeA algorithm due to Campan and Truta which is the leading algorithm for achieving anonymity in networks by means of clustering. We then devise secure distributed versions of our algorithms. To the best of our knowledge, this is the first study of privacy preservation in distributed social networks. We conclude by outlining future research proposals in that direction.

Over the last forty years, there has only been a modest change in the overall interstate migration rate. However, different demographic groups have seen very different patterns of changes. The migration rate for families with two college graduate spouses dropped from 5.66% in 1965-1970 to 2.82% in 2000- 2005. As for the families with only a college-graduate husband, it dropped from 4.05% to 2.15% during the same time frame. Interstate migration rates for other types of families or singles have seen little change. This paper extends Mincers [1978] family migration model into a search framework and directly estimates the effects of spousal earning difference, correlation of wage offers, and home ownership on the migration propensity. We find that the decreasing difference and correlation of the earnings between the spouses could explain about 50% of the decline in the interstate migration rate for families with two college-graduate spouses and families with a college-graduate husband in the 1980s-1990s. The rising home ownership is the primary determinant, which accounts for about 60% of the decrease in the migration rate of highly educated families, in the 1990s-2000s.

Background/Context: American higher education witnessed rapid expansion between 1960 and 1980, as colleges and universities welcomed millions of new students. The proportion of 19- and 20-year-old students living in dormitories, rooming houses, or other group quarters fell from more than 40% to slightly less than a third. At the same time, the proportion of students in this age group living at home with one or two parents increased from about 35% to nearly 47%, becoming the largest segment of the entering collegiate population in terms of residential alternatives. While growing numbers of high school graduates each fall headed off to campus dormitories, even more enrolled in commuter institutions close to home, gaining their initial collegiate experience in circumstances that may not have differed very much from what they had experienced in secondary school. The increased numbers of commuter students, whether they attended two-year or four-year institutions, however, have received little attention from historians and other social scientists.Purpose/Objective/Research Question/Focus of Study: This study focuses on students aged 19 and 20 who lived with parents and commuted from home during the years from 1960 to 1980, when commuters became the largest category of beginning college students. It also addresses the question of how this large-scale change affected the social and economic profile of commuter students in the United States. In this regard, this study can be considered an evaluation of policy decisions intended to widen access to postsecondary institutions. Did the growing number of students living at home represent a democratic impulse in higher education, a widening of access to include groups of students who had previously been excluded from college? The study approaches this question by examining changes in the characteristics and behavior of commuter students across the country. Recognizing the variation in enrollment rates and other educational indices by state or region, this study also focuses on how the individual behavior at the point of college entry is affected by these and other characteristics of the larger social setting, particularly from a historical perspective.Research Design: To grasp the larger picture of historical trends in college enrollment during the period of study, particularly in the growth of commuter students, the first part of the study utilizes state-level data and identifies changes in the number of entering college students who were commuters. In the process, descriptive statistics and ordinary least squares regression are used to identify factors associated with the proportion of college students living with their parents across states. In the second stage of analysis, hierarchical generalized linear modeling, utilizing both state-and individual-level data, is used to consider different layers of contextual effects on individual decisions to enroll in college.Data Collection and Analysis: At the individual level, the principal sources of information are from 1% Integrated Public Use Microdata Samples (IPUMS) for 1960 and 1980. These are individual-level census data that permit consideration of a wide range of variables, including college enrollment. State-level variables are drawn from the published decennial census volumes, from National Center for Education Statistics reports on the number of higher education institutions, and from aggregated IPUMS data.Conclusions/Recommendations: This study finds that commuter students in the United States appear to have benefited from greater institutional availability, the decline of manufacturing, continued urbanization, and a general expansion of the middle class that occurred across the period in question. It was a time of growth for this sector of the collegiate population. Despite rhetoric about wider access to postsecondary education during the period, however, the nation's colleges appear to have continued to serve a relatively affluent population, even in commuter institutions. Although making postsecondary institutions accessible to commuter students may have improved access in some circumstances, for most American youth, going to college appears to have remained a solidly middle-and upper-class phenomenon.

We use data from the National Health Interview Survey from 1997-2009, as included in the Integrated Health Interview Series (IHIS), to examine the impact of other family members' poor health or disability on the emotional well-being of children. In addition to supplying basic socioeconomic and demographic data, this large nationally representative household survey provides information on all family members' overall health and disability status along with multiple indicators of mental health for one "sample child" per family. We analyze how the likelihood of emotional problems in children is affected by different family members' disability and/or poor health. We also examine interactions between the child's socio-demographic characteristics and the negative effects of ill-health or disability in the family.

Nominal urban wages are typically 30% higher than wages in non-metropolitan areas. This dissertation examines the sources of the urban wage premium (UWP) from three perspectives: (1) the urban worker earning the premium; (2) the underlying factors allowing firms to pay the premium; and (3) the location choices of these workers and firms. The UWP is typically modeled as returns to the worker following from productivity spillovers arising through agglomeration economies. However, the cost-of-living has received little attention in these studies; I examine the nominal and real UWP to determine whether these high wages are indeed a windfall. I find substantial evidence that workers are now willing to experience negative real wages so as to benefit from the consumer amenities and ease of access to those amenities in large, dense cities. These results shed light on the growing importance of urban areas as consumption hubs. Having explored the UWP from the workers perspective, I examine the sources of the firm-level productivity that allow them to pay such high wages. In recent decades, the ease of communicating ideas and the shear density of large urban areas have spurred their continued growth; though there is little consensus on the nature of the optimal conditions for stimulating such knowledge spillovers. I analyze the relative importance of industry specialization, diversity and competition across all industries and all metropolitan areas from 1970 to 2004; and find that cross-fertilization of ideas across industries is a key determinant of growth, with competition spurring the rapid adoption of any innovation. To complement this work, I examine the influence of production amenities on the location decision of households and firms. While there have been numerous contributions to the literature regarding the specific urban amenities that are appealing to households, there has been limited prior work exploring the specific production amenities that are attractive to firms. Within the analytical framework of hedonic wages and housing prices, I find that firms and households have very similar preferences for amenities such as climate, low crime rates, and government services; except that firms have a strong preference for a high level of industry diversity.

Researchers and retailers have documented that consumption declines before the receipt of income, and then rises afterwards. In this paper, we identify a related phenomenon, where mortality rises immediately afterincome receipt. We find that mortality increases following the arrival of monthly Social Security payments, regular wage payments for military personnel, the 2001 tax rebates, and Alaska Permanent Fund dividend payments. The increase in short-run mortality is large, and occurs for many different causes of death.

This study of the determination of earnings among the adult foreign-born population using the 2006 Canada Census of population recognizes that younger children learn a second language more easily than older children and adults. Based on this psycho-biological phenonmenon, an instrumental variable is constructed in an earnings regressions for language proficiency based upon age at arrival to the country. This research uses both Two-steage Least Square estimation and Ordinary Least Square. It is found that there is an association between immigrants' ages at arrival and language skills. The results indicate that there is a significant positive effect of English and French proficiency on earnings among adults who immigrate to Canada at early ages. These results show that least square underestimates rather than overstates the two stages least squares results.

This dissertation examines the impact of race on the life experiences and social outcomes among second generation adults of Nigerian descent in the U.S. and the U.K. Using data from 150 semi-structured in-depth interviews, (75 in each country) the following questions are addressed: 1) How does the educational and occupational attainment of the second generation compare to their parents? (2) What are their ethnic identities? (3) What are their relations like with their proximal hosts, African-Americans in the U.S. and Black-Caribbeans in the U.K.? In both countries, the adult second generation of Nigerian descent in this sample are solidly middle and upper class, with no evidence of downward mobility vis a vis their parents. In both countries, subjects reported tensions with their proximal hosts African-Americans in the U.S. and Black-Caribbeans in the U.K., mostly when they were children, adolescents, and teenagers. This laid the foundation of intra-black ethnic diversity and the articulation of ethnic difference now that they are adults. Interviews reveal an ethnic core among my subjects that is impervious to ethnic labels and is cross-national and which has “consequential commonality.” Over time and in adulthood middle class status blurs the ethnic boundaries between my subjects and their proximal hosts. Second generation Nigerians in the U.S. were much more likely to adopt an American identity than their counterparts were to adopt a British identity. These differences are explained with reference to each country's history which includes colonialism, slavery, black civil rights, its racial and ethnic arrangements, the racial and ethnic diversity of its population, its social construction of the proximal host, its approach to dealing with its ethnic and racially diverse population, and its antidiscrimination laws.

This paper aims to build a database of the small area statistics about population of the six major cities in Japan and show how it can be used as the first step to build the historical GIS of modern Japanese cities. This database utilizes statistical materials about the National Censuses and the regional censuses from 1908 to 1990 in the six cities of Tokyo, Yokohama, Nagoya, Kyoto, Osaka and Kobe. The database contains the small area statistics and the boundary data corresponding to them. A case study about population changes in Tokyo from 1908 to 1990 suggests that spatiotemporal analyses of these cities using the historical GIS could lead to new findings in urban studies in Japan.

A large literature in sociology concerns the implications of immigrants participation in ethnic enclaves for their economic and social well-being. The enclave thesis speculates that immigrants benefit from working in ethnic enclaves. Previous research concerning the effects of enclave participation on immigrants economic outcomes has come to mixed conclusions as to whether enclave effects are positive or negative. In this article, we seek to extend and improve upon past work by formulating testable hypotheses based on the enclave thesis and testing them with data from the 2003 New Immigrant Survey (NIS), employing both residence-based and workplace-based measures of the ethnic enclave. We compare the economic outcomes of immigrants working in ethnic enclaves with those of immigrants working in the mainstream economy. Our research yields minimal support for the enclave thesis. Our results further indicate that for some immigrant groups, ethnic enclave participation actually has a negative effect on economic outcomes.

Southern and non-Southern labor markets entered theperiod of economic restructuring from different starting points. Industrial and occupational differences across regions were eroded by the growth of the service industry in all regions, the decline in personal services withinthe South, and the decline of unions and manufacturing jobs outside of the South. This analysis underscores that indicators of precarity such as unionization and part-time jobs are really at the core of understanding regional low-wage earnings convergence. Furthermore, the authors find that an interaction between the regional structure of occupational opportunities and the racial and gender makeup of workers in jobs, particularly black women, plays an important role in producing the sharp low-wage earningsgrowth observed in the South in the 1970s and 1980s.

The current study attempts a simultaneous testing of economic models, the gender display perspective, and gender-deviance neutralization hypothesis that attempt to explain present housework arrangements between men and women. The study uses fixed effects models that can produce more robust coefficients than the standard regression models generally used in cross-sectional designs. The findings in the study reveal the inadequacy of economic models and the gender display theory to account for mens housework behavior. The study introduces the marital contract hypothesis as an alternative theoretical framework for explaining mens housework behavior. According to the study, what is crucial for achieving housework parity is changes in womens gender related attitudes and their economic and labor market standing and orientation to paid work. The study suggests that attempting to change mens gender beliefs can do little to achieve the goal of housework parity.

The U.S. gender wage gap shrank steadily during the last quarter of the past century. Con- currently, the occupational composition of women converged to that of men as they left the home-sector, entered previously male dominated professional and managerial occupations, and started switching occupations as frequently as their male colleagues. Previous work has associ- ated these gender-related labor market trends with either technological or institutional changes but did not decompose the outcomes in a unified general equilibrium setting. This paper at- tempts to do that. Our contribution is twofold. First, we structurally estimate gender-specific occupational entry and mobility cost parameters using Current Population Survey data. We find that the cost of switching to professional and managerial occupations relative to clerical occupations is 42% to 67% higher for women than it is for men. We also find a declining gap over time. Second, we simulate the estimated model to address the following question: what is the fraction of the reduced gender wage gap that can be attributed to the decreased mobility costs for women, and to shifts in the occupational wage structure?

This study seeks to determine the relative impacts of various factors in affecting ridership, to quantify their short-run and long-run effects, and to test the symmetry in ridership in response to rises and falls in gasoline price and transit fare. The results show that the effect of gasoline price, albeit small, is significant, extends over a year and mainly derives from its rise not fall. Fare is most influential both in terms of shortterm and long-term elasticities and its effect is largely contributed by fare increases. The combination of these two results points to the policy of increasing gasoline price over decreasing transit fare to encourage ridership. On the relationship between service and fare, the results support the 'demand follows supply' hypothesis. The results also provide empirical evidence that ridership responds differentially between a rise and a fall in gasoline price or transit fare.

More than a half century after its peak, the baby booms causes remain a puzzle. A new argument posits that rapid advancements in household technology from 1940 to 1960 account for this large increase in fertility. We present new empirical evidence that is inconsistent with this claim. Rapid advances in household technology began long before 1940 while fertility declined; differences and changes in appliance ownership and electrification in U.S. counties are negatively correlated with fertility rates from 1940 to 1960; and the correlation between children ever born (measured at ages 41 to 60) and access to electrical service in early adulthood is negative for the relevant cohorts of women. Moreover, the Amish, a group strictly limiting the use of modern household technologies, experienced a sizable and coincident baby boom. A final section reconciles this evidence with economic theory by allowing households to have utility over home-produced commodities that are substitutes for the number of children.

Income tax systems are very different across OECD countries. In this thesis, I study the impact of differences in the progressivity of the tax schedule and in the unit of taxation on female labor supply. More precisely, in the first essay I quantify the impact of income tax reforms on female labor supply in the United States, and in the second essay I quantify to what extent differences in income taxation between the United Statesand Europe explain differences in female labor supply.