Redes Sociais Pessoais de Idosos, Satisfação com as Relações Interpessoais e Confiança

Objetivos: O presente estudo tem como objetivo geral caracterizar as redes sociais pessoais dos idosos com idade igual ou superior a 65 anos, analisando-as segundo o nível de satisfação com as relações interpessoais e a confiança nos outros. Metodologia: Este é um estudo descritivo e correlacional, privilegiando a análise bivariada. Os dados foram recolhidos através do Instrumento de Análise da Rede Social Pessoal, IARSP-Idosos (Guadalupe, 2009; Guadalupe & Vicente, 2012) e de uma escala de avaliação da Satisfação com as Relações Interpessoais, construída para o efeito, e de uma questão relacionada com a Confiança. Participantes: A amostra é constituída por 446 indivíduos, maioritariamente do sexo feminino (n=285; 63,9%), com idades compreendidas entre os 65 e os 98 anos; a maioria tem filhos (n = 389; 87,2%), e cerca de 80,0% (n = 357) vivem na sua casa, sendo a zona de residência essencialmente rural (61,2%; n = 273). A maioria tem escolaridade (65,9%; n = 294), sobretudo ao nível do quarto ano (n= 226; 50,7%). Resultados: Os resultados demonstram que os idosos do sexo feminino, com ≤ 75 anos, casado/a ou em união de fato, com filhos, que vivem acompanhados, com o 4ª ano de escolaridade e que não registam qualquer corte relacional, são os que mais confiam nos outros. Registam-se diferenças nas características funcionais da rede segundo esta variável, o que não acontece nas estruturais, com a exceção da proporção das relações com técnicos (p = 0,042) e nas relacionais-contextuais. A confiança nas pessoas com quem se relaciona correlaciona-se de forma positiva e estatisticamente significativa com a satisfação com os filhos, com os netos, com outros parentes, com os amigos e com os vizinhos (p<0,001). Conclusões: Numerosas variáveis sociodemográficas não aparentam estar relacionadas com a confiança nas pessoas com quem os idosos se relacionam, nas múltiplas dimensões consideradas. Em contrapartida, as variáveis que aparecem relacionadas com a confiança, são aquelas que, de forma mais ou menos direta, estão igualmente associadas ao domínio pessoal. É de salientar que no que respeita a esta variável se verificam diferenças nas características funcionais da rede o que não acontece nas estruturais e nas relacionais-contextuais. As relações familiares de filhos, netos e outros parentes são as que mais se associam à confiança e ao apoio social percebido pelos idosos, o qual é complementado por outras relações interpessoais, designadamente as que são estabelecidas com amigos e vizinhos. / Objetives: This study has the general objective to characterize the personal social networks of the elderly aged over 65 years, analyzing them according to the level of satisfaction with interpersonal relationships and trust in others. Methodology: This is a descriptive and correlational study, focusing on bivariate analysis. Data were collected through the Personal Social Networks Analysis Tool, IARSP-Elderly (Guadalupe, 2009; Vicente & Guadalupe, 2012) and a scale measuring satisfaction with interpersonal relations, purpose built, and a question related to the trust. Participants: The sample includes 446 individuals, mostly female (n = 285; 63,9%), aged between 65 and 98 years old; most have sons/daughters (n = 389; 87,2%), and about 80,0% (n = 357) are living in their home, mostly in rural areas (61,2%, n = 273). The majority have education (65,9%, n = 294), especially at the level of the fourth year (n = 226; 50,7%). Results: The results show that the elderly female, with <= 75, married, with children, living together, with the 4th grade, and did not record any relational cut, are the ones that rely in the others. We found differences in the functional characteristics of the network according to this variable, what does not happen on the structural variables, with the exception of the proportion of relations with workers in social services (p = 0,042), and on the relational-contextual. The confidence in the people he meets, correlates positively and statistically significant satisfaction with the children, with grandchildren, other relatives, friends and neighbors (p <0,001) Conclusions: Numerous sociodemographic variables do not appear to be related to trust in the interpersonal relationship, in the multiple dimensions considered. In contrast, the variables which appear related to trust are those which are associated with the personal domain. It is noteworthy that we have found differences in the functional characteristics of the network but not in the structural and the relational-contextual. Family relationships of children, grandchildren and other relatives are the most associated to the confidence and social support perceived by the elderly, which is complemented by other interpersonal relationships, including those with established friends and neighbors.

As Características das Redes Sociais Pessoais de Idosos Segundo o Estado Civil

Objetivos: O presente estudo tem como principal objetivo caraterizar as redes sociais pessoais dos idosos com idade igual ou superior a 65 anos, relativamente às caraterísticas estruturais, funcionais e relacionais-contextuais, analisando-as segundo o estado civil. Metodologia: Para avaliar as variáveis em estudo foram utilizados: o instrumento de Análise da Rede Social Pessoal, versão para idosos (IARSP – Idosos) (Guadalupe, 2010; Guadalupe & Vicente, 2012) com o objetivo de avaliar as dimensões da rede social pessoal dos idosos e um inquérito por questionário para caracterização sociodemográfica. Participantes: A amostra é constituída por 446 idosos com idades compreendidas entre os 65 anos e os 98 anos (M = 76,09; DP = 7,59). Os participantes são na sua maioria do sexo feminino (n = 285, 63,9%). A maioria dos idosos é casada/união de facto (n = 230, 51,6%) e em minoria encontram-se os divorciados/separados (n = 21, 4,7%) e têm filhos (n=389, 87,2%). Resultados: Os resultados demonstram que o estado civil apresenta associações estatisticamente significativas com as variáveis sociodemográficas sexo, idade, viver só, parentalidade e escolaridade. Registam-se diferenças significativas relativamente ao estado civil no que diz respeito à maioria das características estruturais da rede, quanto às características funcionais, nomeadamente o acesso a novos vínculos, a reciprocidade de apoio, a satisfação com a rede e com o suporte social, e quanto às características relacionais-contextuais apenas se assinalam relativamente à distância de residência. Conclusões: O nosso estudo revela que as redes sociais pessoais dos idosos se diferenciam a nível estrutural e funcional segundo o estado civil destes idosos. Os idosos casados apresentam redes maiores mais centradas nas relações familiares na rede do que os idosos com outros estados civis. Os idosos solteiros são os que apresentam redes menores, mais investidas nas relações de amizade e de vizinhança e menos nas relações familiares comparativamente com os outros tipos de relacionamento. / Objectives: This study aims to characterize the personal social networks of the elderly aged 65 years or more, for structural, functional and relational-contextual features, analyzing them according to marital status. Methodology: To assess the variables studied the following was used: the analysis tool of the Personal Social Network, version for elderly (IARSP - Elderly) (Guadalupe, 2010; Guadalupe & Vicente, 2012) in order to assess the dimensions of the personal social network of the elderly and a questionnaire for socio-demographic characterization. Participants: The sample comprises 446 elderly, aged between 65 years and 98 years (M = 76.09, SD = 7.59). Participants are mostly female (n = 285, 63.9%). Most seniors are married / consensual union (n = 230, 51.6%) and a minority is divorced / separated (n = 21, 4.7%) and have children (n = 389, 87. 2%). Results: The results show that marital status has statistically significant associations with the sociodemographic variables, gender, age, living alone, and parenting and education. There are significant differences with regard to marital status relating to most of the structural characteristics of the network, for the functional features, namely access to new links, reciprocal support, satisfaction with the network and social support, and as to the relational-contextual characteristics these only appear in relation to the distance of residence. Conclusions: Our study shows that personal social networks of the elderly are different on a structural and functional level according to the marital status of these seniors. Married elderly have larger networks more centered on family relationships on the network than the elderly with other marital statuses. The single elderly are those with smaller networks, more invested in the relations of friendship and neighborhood and less on family relationships compared to other types of relationship.

Rede Social Pessoal de Cuidadores Informais de Adultos com Necessidades Especiais

Objetivo. Devido ao aumento da esperança de vida, os adultos com necessidades especiais vivem mais tempo, sendo os seus principais cuidadores, geralmente familiares, também mais envelhecidos. Tal situação representa novas necessidades específicas de apoio, sendo inúmeros os desafios colocados ao Serviço Social no sentido de garantir o bem-estar da pessoa com incapacidade e dos seus cuidadores. Assim, este estudo tem como objetivo realizar um levantamento das necessidades de apoio e a caraterização da rede social pessoal de apoio do cuidador informal de adultos com necessidades especiais. Participantes. A amostra é constituída por 40 cuidadores informais de adultos com necessidades especiais, integrados na resposta social “Centro de Atividades Ocupacionais-CAO” da Associação de Paralisia Cerebral de Coimbra, de ambos os sexos com idade igual ou superior a 40 anos. Material e métodos. Foi utilizado o Instrumento de Avaliação da Rede Social Pessoal e um questionário para caracterização sociodemográfica e sociofamiliar dos cuidadores, assim como para avaliação de necessidades. Resultados. Aproximadamente um terço dos cuidadores relatou a experiência de níveis moderados de sobrecarga associada à prestação de cuidados, enquanto mais de metade relatou a experiência de níveis elevados e muito elevados dessa sobrecarga; o apoio financeiro foi referido como a forma de apoio mais necessária no presente, ainda que o apoio em residência tenha sido percecionado por cerca de um terço dos cuidadores como a forma de apoio mais necessária no futuro; enquanto mais de metade considerou o apoio domiciliário e de unidade residencial (institucional). Estes cuidadores familiares referiram a "incerteza" e a "esperança" como os sentimentos mais frequentemente experienciados em relação ao futuro das suas vidas. No que respeita às redes sociais, as relações familiares são centrais a nível estrutural; em termos de caraterísticas funcionais da rede, foram observados valores mais elevados para as dimensões de reciprocidade do apoio e satisfação com a rede social. Implicações. Este estudo sublinha a importância da avaliação das necessidades de apoio dos cuidadores familiares de adultos com necessidades especiais. A sua implementação sistemática pode auxiliar a tomada de decisão baseada na evidência empírica para as intervenções do Serviço Social, tais como na planificação e gestão de respostas e serviços sociais, a par do reconhecimento e ativação dos recursos das próprias famílias, de forma a promover a eficiência dos recursos e eficácia das intervenções, focadas no bem-estar do cidadão com deficiência e das suas famílias. / Aim. The general increase in human life expectancy has resulted in greater rates of survival for adults with special care needs, as well as for their ageing family caregivers. This situation poses different and specific support needs, which represent a major challenge in social work interventions aimed at ensuring the well-being of disabled persons and their caregivers. Therefore, this study was aimed to describe the needs for support and the perceived social support network of family caregivers of adults with special care needs. Participants. The sample for this study comprised 40 family caregivers of disabled adults with special care needs, of both genders and aged 40 years old at minimum, who attended a long-term care facility at Coimbra Cerebral Palsy Association. Material and methods. Participants were administered a self-report questionnaire on socio-economic, family and caregiving needs, along with the Instrument for Assessing Personal Social Networks. Results. Nearly one third a family caregivers experienced moderate caregiving burden, while more than half experienced high or very high levels of caregiving burden; financial support was perceived as the most needed form of support in the present, but residential home care was identified as the most needed form of support in the future; while more than a half considered home-based support and residential support viable options for their disabled family members with special care needs. These family caregivers reported "uncertainty" and "hope" as the most common feelings towards their family life in the future. On the topic of social networks, family relations were found to be crucial at the structural level; in terms of functional characteristics of the network, elevated scores were observed for reciprocity of support and satisfaction with the social network. Implications. This study highlights the importance of increasing the specificity of the assessments of needs for support in family caregivers of disabled adults with special care needs. The systematic conduction of these assessments may assist evidence-based decision making in social work interventions, such as for planning and managing social services, acknowledging and activating the families' own resources, and ultimately promote the efficacy and effectiveness 57 interventions aimed at improving the well-being of disabled citizens and their families.

Relações interorganizacionais e eficiência coletiva: um estudo de caso no arranjo produtivo local de confecções do Agreste de Pernambuco

This work is a study in the Local Productive Arrangement of confections from Agreste of Pernambuco, as a relevant sector in economic and social aspect. This research has as central aim to understand how the inter-organizational relations influence the collective efficiency of arrangement. The theoretical framework employed highlights the approaches that deal with the benefits of business agglomeration for the develop­ment of firms and regions. It has discussed the approach of small and medium enter­ prises and industrial districts (SCHMITZ, 1997), which introduce the concept of col­ lective efficiency, explaining that only those externalities explained by Marshall (1996) are not sufficient to explain the competitive advantage of enterprises, expand­ing the idea that organizations achieve competitive advantage not acting alone. To examine the influences of relations in the collective efficiency, it has been taken as analytical perspective theory of social networks (GRANOVETTER, 1973, 1985; BURT, 1992; UZZI, 1997) because it has believe that this approach provides subsi­ dies for a structural analysis of social relationships in face the behavior of human ac­tion. By examining the organizations in a social network, you should understand the reason of this establishment of the relationship, their benefits, and as the information flow takes place and density of links between the actors (Powell; SMITH-DOERR, 1994). As for the methods, this study is characterized as a case study, in according to the purposed objectives, in addition to qualitative method. Also, due to recovering of the historical milestones of the arrangement, it is used a sectional approach with longitudinal perspective (VIEIRA, 2004). The primary and secondary data were used in order to understand the evolutionary process of the sector and their inter-actors re­ lationships in the arrangement for the promotion of development, for both, was used the contend and documentary analysis technique, respectively (DELLAGNELO ; SIL­VA, 2005). The approach of social networks has permitted understand that social re­lationships may extend the collective efficiency of the arrangement, and therefore need to develop policies that encourage the legalization of informal companies in ar­rangement, by showing up themselves representative. Thus, the relations estab­ lished in LPA of confections from Agreste of Pernambuco need for more effective mechanisms to broaden the collective efficiency. Therefore, this way as take place has directly benefited only a group of companies that are linked in some way the sup­portive institutions. So we can conclude that the inter-actor relations have limited the collective efficiency of LPA, being stimulated by the institutions in support only to groups of entrepreneurs, even those that produce external relations for all clustered companies

Redes interorganizacionais e inovação: o caso do pólo joalheiro de Belém

This work is a case study based on Belém Jewelry Pole, whose main issue is to understand how the social network (which the Pole is inserted) influences on innovation process on this area. The main objective is to analyze how interorganizational networks impacted/impact on the potential for innovation, creating both limits and opportunities for the companies development. The adopted method analyzed the historical jewelry industry trajectory since the beginning of mineral extraction in the city of Itaituba (in the Pará State) until nowadays. Primary and secondary data were used allowing the view of the dynamics of the network during transformation periods of the main involved actors in the process. The prospect of embeddedness structural as analysis technique allowed verifying the quality of interactors ties, as well as the visualization of their structures. During the jewelry industry trajectory was verified a change in the quality of social relations, modifying the information flow, trust and associations of various links in the production chain. Both direct and indirect ties facilitated the access to remote networks entering new information related to new products, processes and market aspects. This interaction has led to raising the innovation potential causing a qualitative and quantitative improvement in competitiveness of organizations. Some embedded ties allowed the formation of partnerships bringing various economic earnings for those involved in the relationship. Thus, it is understood how aspects related to the position, architecture and quality of ties in a wide social network influenced on the innovation process and eventual jewelry industry trajectory

Good year, bad year: changing strategies, changing networks? A two-year study on seed acquisition in northern Cameroon

Analysis of seed exchange networks at a single point in time may reify sporadic relations into apparently fixed and long-lasting ones. In northern Cameroon, where environment is not only strongly seasonal but also shows unpredictable interannual variation, farmers’ social networks are flexible from year to year. When adjusting their strategies, Tupuri farmers do not systematically solicit the same partners to acquire the desired propagules. Seed acquisitions documented during a single cropping season may thus not accurately reflect the underlying larger social network that can be mobilized at the local level. To test this hypothesis, we documented, at the outset of two cropping seasons (2010 and 2011), the relationships through which seeds were acquired by the members of 16 households in a Tupuri community. In 2011, farmers faced sudden failure of the rains and had to solicit distant relatives, highlighting their ability to quickly trigger specific social relations to acquire necessary seeding material. Observing the same set of individuals during two successive years and the seed sources they solicited in each year enabled us to discriminate repeated relations from sporadic ones. Although farmers did not acquire seeds from the same individuals from one year to the next, they relied on quite similar relational categories of people. However, the worse weather conditions during the second year led to (1) a shift from red sorghum seeds to pearl millet seeds, (2) a geographical extension of the network, and (3) an increased participation of women in seed acquisitions. In critical situations, women mobilized their own kin almost exclusively. We suggest that studying the seed acquisition network over a single year provides a misrepresentation of the underlying social network. Depending on the difficulties farmers face, they may occasionally call on relationships that transcend the local relationships used each year.

Music Learning Networks: Supporting the Music Learning of Adolescents

Thesis (Ph.D.)--University of Washington, 2016-08

El impacto de la red social twitter en la información local del diario El Tiempo y El Mercurio en el periodo febrero-junio

La red social Twitter da sus comienzos en el año 2006, su idioma inicial fue el inglés, su principal función es la de crear textos de 140 caracteres para dar a conocer información, dentro de una empresa, pero con el pasar del tiempo esta herramienta fue evolucionando hasta convertirse en la primera red de aceptación como apoyo para el periodismo digital. El Periodismo actual se está ayudando de herramientas tecnológicas como el Twitter para poder aportar noticias o acontecimientos que se generan dentro del territorio local, nacional y también a nivel internacional. Los diarios locales como: diario El Tiempo y diario El Mercurio dieron sus inicios a la era digital al mismo tiempo, ambos medios de comunicación poseen sus respectivas versiones electrónicas con las cuales informan a la ciudadanía ecuatoriana y a las personas que viven fuera del país. Los periodistas han aportado con conocimientos y experiencias personales en el manejo de Twitter como herramienta esencial que tiene el periodismo en la actualidad, también están de acuerdo que los periodistas necesitan de la última tecnología para poder sacarle el mayor provecho a esta red social, poseer dispositivos móviles facilita el desempeño periodístico y se puede twittear desde cualquier lugar donde acontecen hechos noticiosos.

Towards Proactive Context-aware Computing and Systems

A primary goal of context-aware systems is delivering the right information at the right place and right time to users in order to enable them to make effective decisions and improve their quality of life. There are three key requirements for achieving this goal: determining what information is relevant, personalizing it based on the users’ context (location, preferences, behavioral history etc.), and delivering it to them in a timely manner without an explicit request from them. These requirements create a paradigm that we term as “Proactive Context-aware Computing”. Most of the existing context-aware systems fulfill only a subset of these requirements. Many of these systems focus only on personalization of the requested information based on users’ current context. Moreover, they are often designed for specific domains. In addition, most of the existing systems are reactive - the users request for some information and the system delivers it to them. These systems are not proactive i.e. they cannot anticipate users’ intent and behavior and act proactively without an explicit request from them. In order to overcome these limitations, we need to conduct a deeper analysis and enhance our understanding of context-aware systems that are generic, universal, proactive and applicable to a wide variety of domains. To support this dissertation, we explore several directions. Clearly the most significant sources of information about users today are smartphones. A large amount of users’ context can be acquired through them and they can be used as an effective means to deliver information to users. In addition, social media such as Facebook, Flickr and Foursquare provide a rich and powerful platform to mine users’ interests, preferences and behavioral history. We employ the ubiquity of smartphones and the wealth of information available from social media to address the challenge of building proactive context-aware systems. We have implemented and evaluated a few approaches, including some as part of the Rover framework, to achieve the paradigm of Proactive Context-aware Computing. Rover is a context-aware research platform which has been evolving for the last 6 years. Since location is one of the most important context for users, we have developed ‘Locus’, an indoor localization, tracking and navigation system for multi-story buildings. Other important dimensions of users’ context include the activities that they are engaged in. To this end, we have developed ‘SenseMe’, a system that leverages the smartphone and its multiple sensors in order to perform multidimensional context and activity recognition for users. As part of the ‘SenseMe’ project, we also conducted an exploratory study of privacy, trust, risks and other concerns of users with smart phone based personal sensing systems and applications. To determine what information would be relevant to users’ situations, we have developed ‘TellMe’ - a system that employs a new, flexible and scalable approach based on Natural Language Processing techniques to perform bootstrapped discovery and ranking of relevant information in context-aware systems. In order to personalize the relevant information, we have also developed an algorithm and system for mining a broad range of users’ preferences from their social network profiles and activities. For recommending new information to the users based on their past behavior and context history (such as visited locations, activities and time), we have developed a recommender system and approach for performing multi-dimensional collaborative recommendations using tensor factorization. For timely delivery of personalized and relevant information, it is essential to anticipate and predict users’ behavior. To this end, we have developed a unified infrastructure, within the Rover framework, and implemented several novel approaches and algorithms that employ various contextual features and state of the art machine learning techniques for building diverse behavioral models of users. Examples of generated models include classifying users’ semantic places and mobility states, predicting their availability for accepting calls on smartphones and inferring their device charging behavior. Finally, to enable proactivity in context-aware systems, we have also developed a planning framework based on HTN planning. Together, these works provide a major push in the direction of proactive context-aware computing.

BUILDING EFFICIENT AND COST-EFFECTIVE CLOUD-BASED BIG DATA MANAGEMENT SYSTEMS

In today’s big data world, data is being produced in massive volumes, at great velocity and from a variety of different sources such as mobile devices, sensors, a plethora of small devices hooked to the internet (Internet of Things), social networks, communication networks and many others. Interactive querying and large-scale analytics are being increasingly used to derive value out of this big data. A large portion of this data is being stored and processed in the Cloud due the several advantages provided by the Cloud such as scalability, elasticity, availability, low cost of ownership and the overall economies of scale. There is thus, a growing need for large-scale cloud-based data management systems that can support real-time ingest, storage and processing of large volumes of heterogeneous data. However, in the pay-as-you-go Cloud environment, the cost of analytics can grow linearly with the time and resources required. Reducing the cost of data analytics in the Cloud thus remains a primary challenge. In my dissertation research, I have focused on building efficient and cost-effective cloud-based data management systems for different application domains that are predominant in cloud computing environments. In the first part of my dissertation, I address the problem of reducing the cost of transactional workloads on relational databases to support database-as-a-service in the Cloud. The primary challenges in supporting such workloads include choosing how to partition the data across a large number of machines, minimizing the number of distributed transactions, providing high data availability, and tolerating failures gracefully. I have designed, built and evaluated SWORD, an end-to-end scalable online transaction processing system, that utilizes workload-aware data placement and replication to minimize the number of distributed transactions that incorporates a suite of novel techniques to significantly reduce the overheads incurred both during the initial placement of data, and during query execution at runtime. In the second part of my dissertation, I focus on sampling-based progressive analytics as a means to reduce the cost of data analytics in the relational domain. Sampling has been traditionally used by data scientists to get progressive answers to complex analytical tasks over large volumes of data. Typically, this involves manually extracting samples of increasing data size (progressive samples) for exploratory querying. This provides the data scientists with user control, repeatable semantics, and result provenance. However, such solutions result in tedious workflows that preclude the reuse of work across samples. On the other hand, existing approximate query processing systems report early results, but do not offer the above benefits for complex ad-hoc queries. I propose a new progressive data-parallel computation framework, NOW!, that provides support for progressive analytics over big data. In particular, NOW! enables progressive relational (SQL) query support in the Cloud using unique progress semantics that allow efficient and deterministic query processing over samples providing meaningful early results and provenance to data scientists. NOW! enables the provision of early results using significantly fewer resources thereby enabling a substantial reduction in the cost incurred during such analytics. Finally, I propose NSCALE, a system for efficient and cost-effective complex analytics on large-scale graph-structured data in the Cloud. The system is based on the key observation that a wide range of complex analysis tasks over graph data require processing and reasoning about a large number of multi-hop neighborhoods or subgraphs in the graph; examples include ego network analysis, motif counting in biological networks, finding social circles in social networks, personalized recommendations, link prediction, etc. These tasks are not well served by existing vertex-centric graph processing frameworks whose computation and execution models limit the user program to directly access the state of a single vertex, resulting in high execution overheads. Further, the lack of support for extracting the relevant portions of the graph that are of interest to an analysis task and loading it onto distributed memory leads to poor scalability. NSCALE allows users to write programs at the level of neighborhoods or subgraphs rather than at the level of vertices, and to declaratively specify the subgraphs of interest. It enables the efficient distributed execution of these neighborhood-centric complex analysis tasks over largescale graphs, while minimizing resource consumption and communication cost, thereby substantially reducing the overall cost of graph data analytics in the Cloud. The results of our extensive experimental evaluation of these prototypes with several real-world data sets and applications validate the effectiveness of our techniques which provide orders-of-magnitude reductions in the overheads of distributed data querying and analysis in the Cloud.

Contextual text mining

With the dramatic growth of text information, there is an increasing need for powerful text mining systems that can automatically discover useful knowledge from text. Text is generally associated with all kinds of contextual information. Those contexts can be explicit, such as the time and the location where a blog article is written, and the author(s) of a biomedical publication, or implicit, such as the positive or negative sentiment that an author had when she wrote a product review; there may also be complex context such as the social network of the authors. Many applications require analysis of topic patterns over different contexts. For instance, analysis of search logs in the context of the user can reveal how we can improve the quality of a search engine by optimizing the search results according to particular users; analysis of customer reviews in the context of positive and negative sentiments can help the user summarize public opinions about a product; analysis of blogs or scientific publications in the context of a social network can facilitate discovery of more meaningful topical communities. Since context information significantly affects the choices of topics and language made by authors, in general, it is very important to incorporate it into analyzing and mining text data. In general, modeling the context in text, discovering contextual patterns of language units and topics from text, a general task which we refer to as Contextual Text Mining, has widespread applications in text mining. In this thesis, we provide a novel and systematic study of contextual text mining, which is a new paradigm of text mining treating context information as the ``first-class citizen.'' We formally define the problem of contextual text mining and its basic tasks, and propose a general framework for contextual text mining based on generative modeling of text. This conceptual framework provides general guidance on text mining problems with context information and can be instantiated into many real tasks, including the general problem of contextual topic analysis. We formally present a functional framework for contextual topic analysis, with a general contextual topic model and its various versions, which can effectively solve the text mining problems in a lot of real world applications. We further introduce general components of contextual topic analysis, by adding priors to contextual topic models to incorporate prior knowledge, regularizing contextual topic models with dependency structure of context, and postprocessing contextual patterns to extract refined patterns. The refinements on the general contextual topic model naturally lead to a variety of probabilistic models which incorporate different types of context and various assumptions and constraints. These special versions of the contextual topic model are proved effective in a variety of real applications involving topics and explicit contexts, implicit contexts, and complex contexts. We then introduce a postprocessing procedure for contextual patterns, by generating meaningful labels for multinomial context models. This method provides a general way to interpret text mining results for real users. By applying contextual text mining in the ``context'' of other text information management tasks, including ad hoc text retrieval and web search, we further prove the effectiveness of contextual text mining techniques in a quantitative way with large scale datasets. The framework of contextual text mining not only unifies many explorations of text analysis with context information, but also opens up many new possibilities for future research directions in text mining.

The interplay between social motivation, social experience, and developmental neural specialization for social perception

From birth, infants preferentially attend to human motion, which allows them to learn to interpret other peoples’ facial expressions and mental states. Evidence from adults shows that selectivity of the amygdala and the posterior superior temporal sulcus (pSTS) to biological motion correlates with social network size. Social motivation—one’s desire to orient to the social world, to seek and find reward in social interaction, and to maintain social relationships—may also contribute to neural specialization for biological motion and to social network characteristics. The current study aimed to determine whether neural selectivity for biological motion relates to social network characteristics, and to gain preliminary evidence as to whether social motivation plays a role in this relation. Findings suggest that neural selectivity for biological motion in the pSTS is positively related to social network size in middle childhood and that this relation is moderated by social motivation.

Developmental Neural Correlates of Social Interaction

Children develop in a sea of reciprocal social interaction, but their brain development is predominately studied in non-interactive contexts (e.g., viewing photographs of faces). This dissertation investigated how the developing brain supports social interaction. Specifically, novel paradigms were used to target two facets of social experience—social communication and social motivation—across three studies in children and adults. In Study 1, adults listened to short vignettes—which contained no social information—that they believed to be either prerecorded or presented over an audio-feed by a live social partner. Simply believing that speech was from a live social partner increased activation in the brain’s mentalizing network—a network involved in thinking about others’ thoughts. Study 2 extended this paradigm to middle childhood, a time of increasing social competence and social network complexity, as well as structural and functional social brain development. Results showed that, as in adults, regions of the mentalizing network were engaged by live speech. Taken together, these findings indicate that the mentalizing network may support the processing of interactive communicative cues across development. Given this established importance of social-interactive context, Study 3 examined children’s social motivation when they believed they were engaged in a computer-based chat with a peer. Children initiated interaction via sharing information about their likes and hobbies and received responses from the peer. Compared to a non-social control, in which children chatted with a computer, peer interaction increased activation in mentalizing regions and reward circuitry. Further, within mentalizing regions, responsivity to the peer increased with age. Thus, across all three studies, social cognitive regions associated with mentalizing supported real-time social interaction. In contrast, the specific social context appeared to influence both reward circuitry involvement and age-related changes in neural activity. Future studies should continue to examine how the brain supports interaction across varied real-world social contexts. In addition to illuminating typical development, understanding the neural bases of interaction will offer insight into social disabilities such as autism, where social difficulties are often most acute in interactive situations. Ultimately, to best capture human experience, social neuroscience ought to be embedded in the social world.

Influences and benefits of role models on social media.

The current paper examined three research questions. First, what are the perceived benefits for social network users who have role models online? Second, to what extent does having role models online influence one’s self-presentation on social media? And finally, are users who expect more in return (greater reciprocity) more likely to have role models on social media? Using two opportunity survey samples and exploratory analyses, study 1 (N = 236) demon-strated that having role models was associated with greater perceived support for one’s career aspirations, and perceived access to information. The results of study 2 (N = 192) revealed that participants who had role models online reported that their online profile presented a more realistic self-presentation of values and pri-orities, as well as having higher reciprocity expectation.

ENGINEERING DIGITAL SHARING PLATFORM TO CREATE SOCIAL CONTAGION: EVIDENCE FROM LARGE SCALE RANDOMIZED FIELD EXPERIMENTS

Peer-to-peer information sharing has fundamentally changed customer decision-making process. Recent developments in information technologies have enabled digital sharing platforms to influence various granular aspects of the information sharing process. Despite the growing importance of digital information sharing, little research has examined the optimal design choices for a platform seeking to maximize returns from information sharing. My dissertation seeks to fill this gap. Specifically, I study novel interventions that can be implemented by the platform at different stages of the information sharing. In collaboration with a leading for-profit platform and a non-profit platform, I conduct three large-scale field experiments to causally identify the impact of these interventions on customers’ sharing behaviors as well as the sharing outcomes. The first essay examines whether and how a firm can enhance social contagion by simply varying the message shared by customers with their friends. Using a large randomized field experiment, I find that i) adding only information about the sender’s purchase status increases the likelihood of recipients’ purchase; ii) adding only information about referral reward increases recipients’ follow-up referrals; and iii) adding information about both the sender’s purchase as well as the referral rewards increases neither the likelihood of purchase nor follow-up referrals. I then discuss the underlying mechanisms. The second essay studies whether and how a firm can design unconditional incentive to engage customers who already reveal willingness to share. I conduct a field experiment to examine the impact of incentive design on sender’s purchase as well as further referral behavior. I find evidence that incentive structure has a significant, but interestingly opposing, impact on both outcomes. The results also provide insights about senders’ motives in sharing. The third essay examines whether and how a non-profit platform can use mobile messaging to leverage recipients’ social ties to encourage blood donation. I design a large field experiment to causally identify the impact of different types of information and incentives on donor’s self-donation and group donation behavior. My results show that non-profits can stimulate group effect and increase blood donation, but only with group reward. Such group reward works by motivating a different donor population. In summary, the findings from the three studies will offer valuable insights for platforms and social enterprises on how to engineer digital platforms to create social contagion. The rich data from randomized experiments and complementary sources (archive and survey) also allows me to test the underlying mechanism at work. In this way, my dissertation provides both managerial implication and theoretical contribution to the phenomenon of peer-to-peer information sharing.