Boundary Crossings (boundary + crossing)

Distribution by Scientific Domains
Humanities and Social Sciences40%

Selected Abstracts

Speed-up and performance evaluation of piecewise-linear DC analysis

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2007
Janne RoosArticle first published online: 29 NOV 200
Abstract The good convergence properties of piecewise-linear (PWL) DC analysis have been thoroughly discussed in many papers. This paper, in turn, concentrates on the speed of PWL DC analysis, where the boundary crossing of linear regions plays a crucial role. Fast methods are presented for performing the following boundary-crossing computations: LU-decomposition update, matrix-equation solution, boundary-crossing direction, and damping-factor determination. Special attention is given to those PWL DC analysis methods that perform PWL modelling of the non-linear components on the fly; an adaptive method is proposed for controlling the accuracy of PWL modelling and speeding up simulation. The computational efficiency of the accelerated PWL DC analysis is discussed and compared with that of conventional, Newton,Raphson iteration-based, DC analysis. Finally, the performance evaluation is completed with realistic simulation examples: it is demonstrated that the speed of the accelerated PWL DC analysis is comparable with that of the conventional DC analysis. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Reconceptualizing Collective Action in the Contemporary Media Environment

COMMUNICATION THEORY, Issue 4 2005
Bruce Bimber
Collective action theory, which is widely applied to explain human phenomena in which public goods are at stake, traditionally rests on at least two main tenets: that individuals confront discrete decisions about free riding and that formal organization is central to locating and contacting potential participants in collective action, motivating them, and coordinating their actions. Recent uses of technologies of information and communication for collective action appear in some instances to violate these two tenets. In order to explain these, we reconceptualize collective action as a phenomenon of boundary crossing between private and public domains. We show how a reconceptualized theory of collective action can better account for certain contemporary phenomena, and we situate traditional collective action theory as a special case of our expanded theory. [source]

Island Biocultural Assemblages , The Case of Kinmen Island

GEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 4 2003
Huei-Min Tsai
ABSTRACT A growing mass of research contributes to our understanding of how biological and cultural diversity are related in complex and important ways. This paper presents an assembling process of biodiversity and cultural diversity on an island, Kin-men (Quemoy), based on 1600 years of its environmental history. The study shows that the island's biocultural assemblages are a result both of external relations with the island's surrounding environment and internal relations within the island's changing human ecology. Distant political powers and economic forces are the two major external influences that have affected the flow of natural and cultural elements to and from the island, while ,screening effects' and ,isolation effects' are two factors that explain internal interactions. The island's biocultural assembling processes reveal that the openness of the island facilitates increase in the diversity of biocultural elements, while its less disturbed isolated condition fosters natural succession and co-evolution. The study suggests that biocultural assemblages and the associated processes of co-evolution and nature,society interactions are accomplished through the intermittent opportunities purposively provided by or inadvertently found in the openings and closures of boundaries, setting the scene for both boundary crossings and bounded shelter, by intent or chance. [source]

Behavioural responses to habitat patch boundaries restrict dispersal and generate emigration,patch area relationships in fragmented landscapes

JOURNAL OF ANIMAL ECOLOGY, Issue 4 2003
Nicolas Schtickzelle
Summary 1We studied the consequences of behaviour at habitat patch boundaries on dispersal for the bog fritillary butterfly Proclossiana eunomia Esper in two networks of habitat differing in fragmentation and matrix quality. We tested for differences in responses to patch boundaries according to the fragmentation level of the network by analysing movement paths of adult butterflies. 2Butterflies systematically engaged in U-turns when they reached a boundary in the fragmented network while they crossed over boundaries in more than 40% of boundary encounters in the continuous one. 3We applied the Virtual Migration model (Hanski, Alho & Moilanen 2000) to capture,mark,recapture data collected in both networks. The model indicated (i) a lower dispersal rate and (ii) a lower survival during dispersal in the fragmented network. This latter difference is likely to be the key biological process leading to behavioural avoidance of patch boundary crossings. 4On the basis of this behavioural difference, we designed an individual-based simulation model to explore the relationship between patch area, boundary permeability and emigration rate. 5Predictions of the model fitted observed results of the effect of patch area on emigration rate according to fragmentation: butterflies are more likely to leave small patches than large ones in fragmented landscapes (where patch boundary permeability is low), while this relationship disappears in more continuous landscapes (where patch boundary permeability is high). [source]

Exploring Boundaries in the Nurse-Client Relationship: Professional Roles and Responsibilities

PERSPECTIVES IN PSYCHIATRIC CARE, Issue 2 2003
Cindy A. Peternelj-Taylor MSc
TOPIC. The creation and maintenance of boundaries as they pertain to the nurse-client relationship. PURPOSE. To challenge readers to reflect on their fiduciary responsibilities by identifying boundary crossings and violations. SOURCES. Review of the literature and the authors' clinical and teaching experiences. CONCLUSIONS. Although self-awareness and monitoring, debriefing, and availing oneself of supervision and education are important tools in creating and maintaining boundaries, in the final analysis, the nursing profession needs nurses who have the ability to make decisions about boundaries based on the best interests of the clients in their care. [source]