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Severe Constraints (severe + constraint)

Distribution by Scientific Domains

Humanities and Social Sciences	50%

Selected Abstracts

Treading on Tradition: Approaches to Teaching International Relations to the Nontraditional Undergraduate

INTERNATIONAL STUDIES PERSPECTIVES, Issue 1 2002
Nancy E. Wright
Nontraditional undergraduates (NTUs), undergraduates who typically are older than average, work full-time, and/or are entrusted with substantial family responsibilities, pose a special challenge to international relations educators. Severe constraints on time and access to library facilities both impede progress and may give an erroneous impression that NTUs are not as committed to their education as more conventional college undergraduates. The lack of continuity in education that typifies the NTU experience often manifests itself in anxiety, frustration, and gaps in fundamental knowledge. At the same time, the maturity and sophistication that come with life experience often far exceed that of the more conventional college student. Furthermore, typical requirements of international relations and international studies majors, such as second and third language proficiency, internships with international organizations, and overseas study are often not feasible for the working student with family responsibilities. Possibilities for meeting the challenges of teaching NTUs include greater use of open-book examinations, research proposals, case studies, simulations, problem-based learning (PBL), use of the Internet, and the development of short-term intensive overseas study opportunities that accommodate the working student's schedule. [source]

Resources, techniques, and strategies south of the Sahara: revising the factor endowments perspective on African economic development, 1500,20001

ECONOMIC HISTORY REVIEW, Issue 3 2008
GARETH AUSTIN
This article seeks to revise and re-apply the factor endowments perspective on African history. The propositions that sub-Saharan Africa was characterized historically by land abundance and labour scarcity, and that the natural environment posed severe constraints on the exploitation of the land surplus, are broadly upheld. Important alterations are suggested, however, centred on the seasonality of labour supply, Ruf's concept of ,forest rent', and, for precolonial economies, the role of fixed capital. This revised endowments framework is then applied in order to explore the long-term dynamics of economic development in Africa, focusing on how the economic strategies of producers and political authorities created specific paths of change which shifted the production possibility frontiers of the economies concerned, and ultimately altered the very factor ratios to which the strategies had been responses. [source]

State space sampling of feasible motions for high-performance mobile robot navigation in complex environments

JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 6-7 2008
Thomas M. Howard
Sampling in the space of controls or actions is a well-established method for ensuring feasible local motion plans. However, as mobile robots advance in performance and competence in complex environments, this classical motion-planning technique ceases to be effective. When environmental constraints severely limit the space of acceptable motions or when global motion planning expresses strong preferences, a state space sampling strategy is more effective. Although this has been evident for some time, the practical question is how to achieve it while also satisfying the severe constraints of vehicle dynamic feasibility. The paper presents an effective algorithm for state space sampling utilizing a model-based trajectory generation approach. This method enables high-speed navigation in highly constrained and/or partially known environments such as trails, roadways, and dense off-road obstacle fields. © 2008 Wiley Periodicals, Inc. [source]

Image adaptive point-spread function estimation and deconvolution for in vivo confocal microscopy

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2006
M. Von Tiedemann
Abstract Visualizing deep inside the tissue of a thick biological sample often poses severe constraints on image conditions. Standard restoration techniques (denoising and deconvolution) can then be very useful, allowing one to increase the signal-to-noise ratio and the resolution of the images. In this paper, we consider the problem of obtaining a good determination of the point-spread function (PSF) of a confocal microscope, a prerequisite for applying deconvolution to three-dimensional image stacks acquired with this system. Because of scattering and optical distortion induced by the sample, the PSF has to be acquired anew for each experiment. To tackle this problem, we used a screening approach to estimate the PSF adaptively and automatically from the images. Small PSF-like structures were detected in the images, and a theoretical PSF model reshaped to match the geometric characteristics of these structures. We used numerical experiments to quantify the sensitivity of our detection method, and we demonstrated its usefulness by deconvolving images of the hearing organ acquired in vitro and in vivo. Microsc. Res. Tech. 69:10,20, 2006. © 2006 Wiley-Liss, Inc. [source]