Over the past five years the Artificial Intelligence Center at SRI has been developing a new technology to address the problem of automated information management within real- world contexts. The result of this work is a body of techniques for automated reasoning from evidence that we call evidential reasoning. The techniques are based upon the mathematics of belief functions developed by Dempster and Shafer and have been successfully applied to a variety of problems including computer vision, multisensor integration, and intelligence analysis.
We have developed both a formal basis and a framework for implementating automated reasoning systems based upon these techniques. Both the formal and practical approach can be divided into four parts: (1) specifying a set of distinct propositional spaces, (2) specifying the interrelationships among these spaces, (3) representing bodies of evidence as belief distributions, and (4) establishing paths of the bodies for evidence to move through these spaces by means of evidential operations, eventually converging on spaces where the target questions can be answered. These steps specify a means for arguing from multiple bodies of evidence toward a particular (probabilistic) conclusion. Argument construction is the process by which such evidential analyses are constructed and is the analogue of constructing proof trees in a logical context.
This technology features the ability to reason from uncertain, incomplete, and occasionally inaccurate information based upon seven evidential operations: fusion, discounting, translation, projection, summarization, interpretation, and gisting. These operation are theoretically sound but have intuitive appeal as well.
In implementing this formal approach, we have found that evidential arguments can be represented as graphs. To support the construction, modification, and interrogation of evidential arguments, we have developed Gister. Gister provides an interactive, menu-driven, graphical interface that allows these graphical structures to be easily manipulated.
Our goal is to provide effective automated aids to domain experts for argument construction. Gister represents our first attempt at such an aid. 相似文献
Relative to White families, Black families have been described as relying on extended social networks to compensate for other social and economic disadvantages. The presence or absence of supportive social networks should be especially relevant to young couples entering marriage, but to date there has been little effort to describe the social networks of comparable Black and White newlyweds. The current study addressed this gap by drawing on interviews with 57 first‐married newlyweds from low‐income communities to compare the composition and structure of Black and White couples' duocentric social networks. The results indicated that low‐income Black couples entered marriage at a social disadvantage relative to White couples, with more family relationships but fewer positive relationships and fewer sources of emotional support (for wives), fewer connections to married individuals, and fewer shared relationships between spouses. Black couples' relative social disadvantages persisted even when various economic and demographic variables were controlled. 相似文献
Although the organizational structures and operating procedures of state substance abuse prevention systems vary substantially across states, there is scant empirical research regarding approaches for rigorous assessment of system attributes and which attributes are most conducive to overall effectiveness. As one component of the national cross-site evaluation of the SPF State Incentive Grant Program (SPF SIG), an instrument was developed to assess state substance abuse prevention system infrastructure in order to measure infrastructure change and examine the role of state infrastructure in achieving prevention-related outcomes. In this paper we describe the development of this instrument and summarize findings from its baseline administration. As expected, states and territories were found to vary substantially with respect seven key characteristics, or domains, of state prevention infrastructure. Across the six domains that were assessed using numeric ratings, states scored highest on data systems and lowest on strategic planning. Positive intercorrelations were observed among these domains, indicating that states with high capacity on one domain generally have relatively high capacity on other domains as well. The findings also suggest that state prevention infrastructure development is linked to both funding from state government and the presence of a state interagency coordinating body with decision-making authority. The methodology and baseline findings presented will be used to inform the ongoing national cross-site evaluation of the SPF SIG and may provide useful information to guide further research on state substance abuse prevention infrastructure. 相似文献
A structured 10‐didactic unit intervention was devised to foster adolescents’ time perspective and career decidedness. The study was conducted with 50 adolescents who were selected from a group of 624; 25 of the participants were randomly assigned to the control group and 25 were assigned to the experimental group. They were selected according to their level of career indecision and poor propensity to look to the future. A series of repeated measure analyses of variance were carried out to evaluate pre‐ and posttest differences between the experimental and control groups regarding time perspective and career decidedness. At posttest, the experimental group showed higher levels of continuity, hope, and career decidedness than did the control group. Implications for future practice and research are discussed. 相似文献
The Brazilian organic food sector has experienced important growth during the last two decades. Brazilian smallholders, however, are facing huge challenges to enter and benefit from this growth in a sustainable way. Combining the lens of New Institutional Economics and socio-anthropology, we analyze six experiences of Brazilian smallholders who converted to organics in the 1990s’. Three different food systems are featured in this analysis: an alternative food system, which is strongly interwoven with the Brazilian Agro-ecological movement and two commercial food procurement systems oriented towards domestic and an export markets driven mainly by supermarket chains. The analytical focus was on 1) the governance of these food systems, 2) the constraints farmers are facing within these food systems and, 3) the benefits that they can expect from market inclusion. We highlighted the roles that NGOs, Faith-based organizations and public-related agencies play in supporting the inclusion of smallholders into all three food systems. We confirmed the arguments in support of pursuing the agro-ecological development based model in Brazil, but underlined that there is a critical lack of support for farmers included in the commercial market-oriented food systems. Such a lack is even more critical as the food systems driven by expanding supermarket chains are characterized by strong asymmetric power relations at the expense of smallholders. Considering the reluctance of NGOs and Faith-based organizations to support these farmers, we call for efforts to be made to provide a policy framework to enable public-related entities to secure sustainable inclusion into these systems and exit strategies for those experiencing exclusion from these highly competitive food systems. 相似文献
Working with survivors of trauma is mostly challenging, exhausting, long‐term and often ‘messy’, when interventions that ‘should’ work, don't, or the unexpected arises. Nevertheless, explanations that speak to recovery from trauma more and more rely on neurobiological concepts to account for any positive change. Combining the family systems approach of Murray Bowen and recent research on the brain and trauma, post trauma symptoms are viewed as part of the ‘family emotional process’ even when traumatic events have emanated from outside the family system itself. Variations in responses to trauma, including dissociation and self‐harm are discussed in relation to chronic anxiety and ‘differentiation of self’. 相似文献
This study uses ethnographic research to examine the phenomenon of transnational parenting by migrant mothers from the African Caribbean community and their family who care for the mothers’ children. Twenty women’s narratives demonstrate the complexity of relationships between migrant mothers living and working in New York City and their extended family or kinship caretakers who coparent their children in their countries of origin. The study reveals three main factors that contribute to the success of transnational parenting: (1) informal kinship care-child fostering, (2) remittances, and (3) social networks. Policy and practice implications are explored. 相似文献
This article describes, theorizes and empirically investigates the concept of interactive profit-planning systems (PPS) through the lens of the dynamic capabilities logic. With this conceptualization: interactive PPS capabilities comprise budgeting, forecasting and results-reporting routines, in which top and middle managers interact to create knowledge for sensing, seizing, and business model reconfiguring (to manage strategic business change). Survey data from 331 Australian firms is analyzed employing partial least squares structural equation modeling. The data provides support for two hypotheses: (1) greater market turbulence strengthens the positive effect of interactive PPS capabilities on business unit performance; and (2) greater market turbulence strengthens the positive effect of flexibility values (of organizational culture) on interactive PPS capabilities. Our findings show that interactive PPS capabilities function according to the salient tenets of the dynamic capabilities logic, and clarify the beneficial roles of formal cybernetic control systems and the intertwined involvement of top and middle managers in using dynamic capabilities. 相似文献