471 research outputs found
Cerebral blood flow-guided phenylephrine-induced hypertensive therapy after subarachnoid hemorrhage
No full textBook Review: Slaves of State, Intellectuals of development in Ethiopia: A Genealogy of Development in Ethiopia
No full textTitle: Slaves of States, Intelectuals of Development in Ethiopia: A Genealogy of Development in Ethiopia
Author: Yonas Ashine
Publisher: Chrome Partners, Nairobi
Year of Publication: 202
Book Review: Slaves of State, Intellectuals of development in Ethiopia: A Genealogy of Development in Ethiopia
No full textSemeneh Ayalew Asfaw
Author: Yonas Ashine Demissie
Title: Slaves of State, Intellectuals of development in Ethiopia: A Genealogy of Development in Ethiopia
Makerere Institute of Social Research
Printed by Chrome Partner
Nylon-muscle-actuated robotic finger
No full textThis paper describes the design and experimental analysis of novel artificial muscles, made of twisted and coiled nylon fibers, for powering a biomimetic robotic hand. The design is based on circulating hot and cold water to actuate the artificial muscles and obtain fast finger movements. The actuation system consists of a spring and a coiled muscle within a compliant silicone tube. The silicone tube provides a watertight, expansible compartment within which the coiled muscle contracts when heated and expands when cooled. The fabrication and characterization of the actuating system are discussed in detail. The performance of the coiled muscle fiber in embedded conditions and the related characteristics of the actuated robotic finger are described
OSPF Convergence Times
Full text linkFollowing the merger of telecom and IP networks, there has been a sharp rise in the number and types of multimedia applications such as interactive real-time Voice/Video over IP. This has put a new service requirement on IP networks and thus has required the IP network solution providers and telecom operators to device new techniques and optimizations to meet the needs of these business critical applications. One way to address these demands is to implement fast and efficient routing mechanism as the data packets are exchanged end to end. Open Shortest Path First (OSPF) is one of the widely deployed routing protocols responsible for this. Most of the important operations of OSPF that contribute to fast convergence such as fast failure detection, shortest path computation and flooding are controlled by timers. These timers, as specified in RFC2328 are fixed and too conservative for modern networks. Today, there has been an increasing effort to make these timers dynamic so that the values are determined based on the experienced network load and stability instead of a preset static value. This thesis is in part a thorough assessment of the state of the art on OSPF timers and fast convergence techniques. The other major contribution of this work is the implementation of the Link State Advertisement (LSA) throttling algorithm as an adaptive technique to control unwanted LSA generations at times of network instabilities. We used two simulators; OPNET Modeler (Academic Version) because of its advanced graphical user interface (GUI) and result analysis tools, and the open source OMNET++ for its open OSPFv2 source code. The outcome of this thesis therefore the work done on literature review which embraces a set of recommended techniques to achieve sub-second convergence, a simulation supported analysis of the associated stability issues in terms of convergence time and CPU load and also the introduction of our own pseudo code and implementation of the LSA throttling algorithm, originally introduced in CISCO 12.0(25) S. The simulation work has proved the LSA throttling algorithm indeed improves a network’s convergence speed and can be deployed on any size OSPF network including large ISP networks consisting of thousands of routers
Evaluation and implementation of error control coding schemes in industrial wireless sensor networks
No full textShort term DC breakdown strength in epoxy based BN nano- and microcomposites
No full textNanocomposites have been known in the field of electrical engineering for more than a decade, albeit there are still uncertainties of how the filler properties influence the properties of the composite material. Filler size, shape, aspect ratio and the surface modification, which consequently leads to even dispersion or clusters of particles, are all suspected to influence the dielectric behaviour of the insulation. But it is disputed what influences the properties to what extent. The focus of this paper is the dependence of the short term breakdown (BD) strength of polymer based composites filled with boron nitride (BN) on the filler size. Base polymer is commercially available bisphenol A epoxy with anhydrite hardener. As filler material we use boron nitride powder with different average particle sizes. These are ranging from 70 to 5000 nm. The particles were not surface modified in order to see solely the influence of the filler size on the BD strength. The short term BD strength was measured for negative DC voltages with Rogowski shaped electrodes. Dielectric spectroscopy was done complementarily to see how the filler size influences the relative permittivity of the composites
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Strategies for the War on Terrorism: Results of a Special Study
Full text linkOn September 13, 2001, the first day after the attacks of September 11 that Sandia National Laboratories re-opened, Vice President Gerry Yonas entirely redirected the efforts of his organization, the Advanced Concepts Group (ACG), to the problem of terrorism. For the next several weeks, the ACG focused on trying to better characterize the international terrorist threat and the vulnerabilities of the US to further attacks. This work culminated in a presentation by Dr . Yonas to the Fall Leadership Focus meeting at Sandia National Laboratories on October 22. Following that meeting, President and Lab Director, Paul Robinson, asked Dr. Yonas and the ACG to develop a long-term (3-5 year) technology roadmap showing how Sandia could direct efforts to making major contributions to the success of the nation's war on terrorism. The ACG effort would communicate with other Labs activities working on near-term responses to Federal calls for technological support. The ACG study was conducted in two phases. The first, more exploratory, stage divided the terrorism challenge into three broad parts, each examined by a team that included both permanent ACG staff and part-time staff and consultants from other Sandia organizations. The ''Red'' team looked at the problems of finding and stopping terrorists before they strike (or strike again). The ''Yellow'' team studied the problems of protecting people and facilities from terrorist attacks, as well as those of responding to attacks that occur. The ''Green'' team attempted to understand the long-term, ''root'' causes of terrorism, and how technology might help ameliorate the conditions that lead people to support, or even become, terrorists. In addition, a ''Purple'' team worked with the other teams to provide an integrating vision for them all, to help make appropriate connections among them, and to see that they left no important gaps between them. The findings of these teams were presented to a broad representation of laboratory staff and management on January 3, 2002. From the many ideas explored by the Red, Green, and Yellow teams, and keeping in mind criteria formulated by the Purple team, the ACG assembled a set of five major technology development goals. These goals, if pursued, could lead to major contributions to the war on terrorism. With some rearrangement of team members and coordinators, a new set of teams began fleshing out these five ''Big Hairy Audacious Goals'' for the consideration of Laboratory leadership. Dr. Yonas briefed Sandia upper management on the work of these teams on February 4, 2002. This report presents the essence of that work as applicable to the R&D community of the nation interested in the development of better tools for a long term ''War on Terrorism.'
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