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111.
Carmen Bain 《Biomass & bioenergy》2011,35(4):1400-1407
The rapid expansion of ethanol plants across the U.S. state of Iowa has fueled debate about the burdens and benefits of local (in-state investors) versus non-local ownership of biorefineries. Central to these concerns is the extent to which non-local, absentee owners might reap the benefits of the ethanol industry at the expense of local communities. A key argument within the rural development literature is that local ownership of firms has a positive effect on the long-term well-being and sustainability of the communities in which they are situated. This literature asserts that firms operate at different scales, with local firms embedded within local supply chains and institutions, and non-local firms embedded within national and international networks and institutions. Conversely, there is a growing body of work within the alternative agrifood systems literature that cautions against the ‘local trap’; the assumption that the local scale is inherently good and therefore advantageous. Despite this broader debate, the literature on local ownership and renewable energy remains limited. This paper addresses this gap by drawing on case study research of the community effects of ethanol plant ownership structure from the perspective of community leaders. My findings suggest that differences between the structure and effects of local versus non-local ownership of firms on communities are rather more ambiguous than the literature asserts. Therefore, assumptions about the benefits of local ownership may be overstated and concepts of ‘local’ and ‘non-local’ may be inadequate for considering firm outcomes on the civic welfare and socioeconomic well-being of a community. 相似文献
112.
In this paper a study was carried out on the feasilibity of using solar energy for a direct space heating of a residential complex in Jordan, constructed from special building materials to reduce heat losses. A computer simulation was carried out for the solar heating system and indicated that an 81 m2 of collecting area was the most cost effective, giving an annual solar contribution to the total annual heating load of 0.987. The remaining portion of the load is to be supplied by an auxiliary system. The economical analysis gave a net saving of almost 27000 J.D over a period of twenty years. 相似文献
113.
Rogério Fernandes Brito Solidônio Rodrigues de Carvalho Sandro Metrevelle Marcondes de Lima e Silva João Roberto Ferreira 《International Communications in Heat and Mass Transfer》2009
This work studies the heat influence in cutting tools considering the variation of the coating thickness and the heat flux. K10 and diamond tools substrate with TiN and Al2O3 coatings were used. The numerical methodology utilizes the ANSYS® CFX software. Boundary conditions and constant thermo physical properties of the solids involved in the numerical analysis are known. To validate the proposed methodology an experiment is used. The TiN and Al2O3 coatings did not show satisfying results during a continuous cutting process. It showed a slight reduction in the heat flux for the 10 (µm) TiN and Al2O3 coatings. 相似文献
114.
Daniel Memmi 《AI & Society》2006,20(3):288-300
The impressive development of electronic communication techniques has given rise to virtual communities. The nature of these computer-mediated communities has been the subject of much recent debate. Are they ordinary social groups in electronic form, or are they fundamentally different from traditional communities? Understanding virtual communities seems a prerequisite for the design of better communication systems. To clarify this debate, we will resort to the classical sociological distinction between small traditional communities (based on personal relations) and modern social groups (bound by looser, more impersonal links). We will argue that the discussion about virtual communities is often vitiated by a simplistic assimilation to traditional communities, whereas they may be in fact quite different and much more impersonal. Virtual communities are often bound by reference to common objects or goals, and not by personal relations. In this respect, virtual communities are just another example of a long-term evolution of modern society toward more abstract social relationships. 相似文献
115.
Writing power into online discussion 总被引:1,自引:0,他引:1
Bill Anderson Author Vitae 《Computers and Composition》2006,23(1):108-124
This article considers the way in which control of interaction emerges as a function of personal agency and external factors in a group of students engaged in online asynchronous text-based communication in a distance education program. It is structured around the argument that control is partly related to the power that individuals have to give effect to their wishes, but also acknowledges that this sense of agency is always in relation to the powers of others and more structural constraints. A picture emerges of the choices students make in deciding when to initiate discussion and respond to others, and about decisions concerning whose messages they would read and when. The impact of other students, of online groups, and instructors seems to play an important role in determining how participants participate in online interaction. Consideration of broader issues shows how the context in which students engage in interaction impacts the nature and extent of that interaction. The article concludes that being aware, and taking advantage of the socially grounded nature of online interaction provides the basis from which educators can act to ensure that interaction in online learning communities is enabling for the learning of all students. 相似文献
116.
Kristie S. Fleckenstein Author Vitae 《Computers and Composition》2005,22(2):149-176
A pedagogical problem growing out of virtual classrooms is the temptation to act without communal accountability, the reciprocal commitment among individuals to maintain the health of their interconnections. Drawing on an ethnographic study of a fully online composition class, I argue that teachers can encourage accountability within virtual sites by conceiving of the online classroom as an emergent phenomenon. The relationships and activities among language, physical reality, and interpretant provide the matrix out of which place organizes itself. This ecological orientation provides local and systemic strategies for fostering communal health. I begin my exploration of online place by describing the value of complex systems theory and emergence for conceptualizing place. Next, I describe the roles of language, physical reality, and interpretant, pointing out the contribution of each to the configuration of virtual place and to communal accountability. Then, I focus on the emergence of place, which reorganizes language, reality, and interpretant, opening up a new dimension to communal accountability. 相似文献
117.
资源搜索和节点管理一直是非结构化Peer-to-Peer (P2P)网络研究的热点.很多不同的搜索策略和分组方案在面临高转换率,freeriding和whitewashing等特殊安全问题时将无法达到原有的性能和效率.文章提出了一个开放的具有抵抗上述特殊问题的群体管理体系结构.主要工作包括:(1)一个新的群体管理体协结构及对应的协议和双层树结构:(2)基于缓存的捷径技术和关键拓扑群体分组技术来优化搜索策略.性能评估表明提出的体系结构具有更好的搜索性能、开放性和对抗特殊问题的能力. 相似文献
118.
This article describes the National Training Conference in Community Psychology, which marked the culmination of several years of planning, starting in 1970, by the Executive Committee of the Division of Community Psychology (APA Division 27). The Conference was held in Austin, Texas, April 27-May 1, 1975, and was sponsored by the Community Psychology Training Program of the University of Texas at Austin Department of Psychology. The Conference served to bring together for informal meetings and discussions the older and newer community psychologists, especially those who had entered the field during the last 5 years, to critically assess the many problems facing community psychology and to examine community psychology's conceptual independence from both clinical psychology and community mental health. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
119.
Managing Role-Based Access Control Policies for Grid Databases in OGSA-DAI Using CAS 总被引:2,自引:0,他引:2
In this paper, we present a role-based access control method for accessing databases through the Open Grid Services Architecture
– Data Access and Integration (OGSA-DAI) framework. OGSA-DAI is an efficient Grid-enabled middleware implementation of interfaces
and services to access and control data sources and sinks. However, in OGSA-DAI, access control causes substantial administration
overhead for resource providers in virtual organizations (VOs) because each of them has to manage a role-map file containing
authorization information for individual Grid users. To solve this problem, we used the Community Authorization Service (CAS)
provided by the Globus Toolkit to support the role-based access control (RBAC) within OGSA-DAI. CAS uses the Security Assertion
Markup Language (SAML). Our method shows that CAS can support a wide range of security policies using role-privileges, role
hierarchies, and constraints. The resource providers need to maintain only the mapping information from VO roles to local
database roles and the local policies in the role-map files, so that the number of entries in the role-map file is reduced
dramatically. Also, unnecessary authentication, mapping and connections can be avoided by denying invalid requests at the
VO level. Thus, our access control method provides increased manageability for a large number of users and reduces day-to-day
administration tasks of the resource providers, while they maintain the ultimate authority over their resources. Performance
analysis shows that our method adds very little overhead to the existing security infrastructure of OGSA-DAI. 相似文献
120.
Washington Lindsay A.; Wilson Sylia; Engel Joyce M.; Jensen Mark P. 《Canadian Metallurgical Quarterly》2007,52(2):241
Objective: To develop and evaluate a new pediatric measure of community integration: the Pediatric Community Participation Questionnaire (PCPQ). Participants: 105 youths with physical disabilities. Measures: In addition to the PCPQ, demographic and disability-related questions and the Functional Disability Inventory (FDI) were administered. Results: The PCPQ demonstrated convergent validity through its high association with functional ability, discriminant validity through its ability to discriminate between ambulatory and nonambulatory participants, and excellent internal consistency. Conclusions: Community participation, an important component of positive overall development, may be particularly important for youths with physical disabilities. The findings from this study provide preliminary support for the validity and reliability of the PCPQ, supporting its use as a measure of community participation with this population. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献