106 Matching Results

Search Results

Advanced search parameters have been applied.

Analysis of the structure of complex networks at different resolution levels

Description: Modular structure is ubiquitous in real-world complex networks, and its detection is important because it gives insights in the structure-functionality relationship. The standard approach is based on the optimization of a quality function, modularity, which is a relative quality measure for a partition of a network into modules. Recently some authors have pointed out that the optimization of modularity has a fundamental drawback: the existence of a resolution limit beyond which no modular structure can be detected even though these modules might have own entity. The reason is that several topological descriptions of the network coexist at different scales, which is, in general, a fingerprint of complex systems. Here we propose a method that allows for multiple resolution screening of the modular structure. The method has been validated using synthetic networks, discovering the predefined structures at all scales. Its application to two real social networks allows to find the exact splits reported in the literature, as well as the substructure beyond the actual split.
Date: February 28, 2008
Creator: Arenas, A.; Fernandez, A. & Gomez, S.
Partner: UNT Libraries Government Documents Department

Size reduction of complex networks preserving modularity

Description: The ubiquity of modular structure in real-world complex networks is being the focus of attention in many trials to understand the interplay between network topology and functionality. The best approaches to the identification of modular structure are based on the optimization of a quality function known as modularity. However this optimization is a hard task provided that the computational complexity of the problem is in the NP-hard class. Here we propose an exact method for reducing the size of weighted (directed and undirected) complex networks while maintaining invariant its modularity. This size reduction allows the heuristic algorithms that optimize modularity for a better exploration of the modularity landscape. We compare the modularity obtained in several real complex-networks by using the Extremal Optimization algorithm, before and after the size reduction, showing the improvement obtained. We speculate that the proposed analytical size reduction could be extended to an exact coarse graining of the network in the scope of real-space renormalization.
Date: December 24, 2008
Creator: Arenas, A.; Duch, J.; Fernandez, A. & Gomez, S.
Partner: UNT Libraries Government Documents Department

Analysis of the connections between modules in the EB.

Description: Over the last several years, calculations have been performed to find the forces that are acting between modules and on the support saddles in the EB. This paper examines these forces and calculates the stresses in the connections between modules. In the Tile Calorimeter, the modules are only connected at three points. First, at the inner radius there is a bearing connection to support the force in the phi direction. Second, at the outer radius there is a bearing connection in the phi direction and, finally, there is a bolted connection designed to withstand the radial load. Each of these connections will be examined separately.
Date: August 1, 2002
Creator: Guarino, V.
Partner: UNT Libraries Government Documents Department

Self-Reconfigurable Robots

Description: A distributed reconfigurable micro-robotic system is a collection of unlimited numbers of distributed small, homogeneous robots designed to autonomously organize and reorganize in order to achieve mission-specified geometric shapes and functions. This project investigated the design, control, and planning issues for self-configuring and self-organizing robots. In the 2D space a system consisting of two robots was prototyped and successfully displayed automatic docking/undocking to operate dependently or independently. Additional modules were constructed to display the usefulness of a self-configuring system in various situations. In 3D a self-reconfiguring robot system of 4 identical modules was built. Each module connects to its neighbors using rotating actuators. An individual component can move in three dimensions on its neighbors. We have also built a self-reconfiguring robot system consisting of 9-module Crystalline Robot. Each module in this robot is actuated by expansion/contraction. The system is fully distributed, has local communication (to neighbors) capabilities and it has global sensing capabilities.
Date: October 1, 2002
Partner: UNT Libraries Government Documents Department


Description: ARM Automation, Inc. is developing a framework of modular actuators that can address the DOE's wide range of robotics needs. The objective of this effort is to demonstrate the effectiveness of this technology by constructing a manipulator from these actuators within a glovebox for Automated Plutonium Processing (APP). At the end of the project, the system of actuators was used to construct several different manipulator configurations, which accommodate common glovebox tasks such as repackaging. The modular nature and quickconnects of this system simplify installation into ''hot'' boxes and any potential modifications or repair therein. This work focused on the development of self-contained robotic actuator modules including the embedded electronic controls for the purpose of building a manipulator system. Both of the actuators developed under this project contain the control electronics, sensors, motor, gear train, wiring, system communications and mechanical interfaces of a complete robotics servo device. Test actuators and accompanying DISC{trademark}s underwent validation testing at The University of Texas at Austin and ARM Automation, Inc. following final design and fabrication. The system also included custom links, an umbilical cord, an open architecture PC-based system controller, and operational software that permitted integration into a completely functional robotic manipulator system. The open architecture on which this system is based avoids proprietary interfaces and communication protocols which only serve to limit the capabilities and flexibility of automation equipment. The system was integrated and tested in the contractor's facility for intended performance and operations. The manipulator was tested using the full-scale equipment and process mock-ups. The project produced a practical and operational system including a quantitative evaluation of its performance and cost.
Date: July 31, 2001
Creator: Joseph W. Geisinger, Ph.D.
Partner: UNT Libraries Government Documents Department

A 3-d modular gripper design tool

Description: Modular fixturing kits are sets of components used for flexible, rapid construction of fixtures. A modular vise is a parallel-jaw vise, each jaw of which is a modular fixture plate with a regular grid of precisely positioned holes. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid-plate to each jaw of a parallel-jaw gripper, one gains the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed an algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses they have added to the planar algorithm, including a 3-d grasp quality metric based on force information, 3-d geometric loading analysis, and inter-gripper interference analysis. Finally, the authors describe two applications of their code. One of these is an internal application at Sandia, while the other shows a potential use of the code for designing part of an agile assembly line.
Date: February 1, 1997
Creator: Brown, R.G. & Brost, R.C.
Partner: UNT Libraries Government Documents Department

Development of standardized, low-cost AC PV systems. Phase I annual report, 7 September 1995--7 November 1996

Description: The objectives of this two-year program are to improve the reliability and safety and reduce the cost of installed grid-connected PV systems by creating standardized, pre-engineered components and an enhanced, low-cost, 250-Watt micro inverter. These advances will be combined with the new, large area Solarex MSX-240 PV module resulting in standard, modular AC PV {open_quotes}building blocks{close_quotes} used to create utility-interactive PV systems as small as one module to many thousands of modules to suit virtually any application. AC PV building blocks will be developed to meet the requirements of the U.S., Japanese and European markets.
Date: June 1, 1997
Creator: Strong, S.J.; Wohlgemuth, J.H. & Kaelin, M.
Partner: UNT Libraries Government Documents Department

Manufactured Residential Utility Wall System (ResCore),

Description: This paper describes the design and development of a manufactured residential utility wall system referred to as ResCore. ResCore is a self contained, manufactured, residential utility wall that provides complete rough-in of utilities (power, gas, water, and phone) and other functions (exhaust, combustion make-up air, refrigerant lines, etc.) to serve the kitchen, bath, utility, and laundry rooms. Auburn University, Department of Industrial Design faculty, students, supported by a team of graduate student researchers and the project`s advisory team, developed the ResCore. The project was accomplished through a research subcontract from the U.S. Department of Energy administered by the Oak Ridge National Laboratory. The ResCore wall system features a layered manufacturing technique that allows each major component group: structural, cold water, hot water, drain, gas, electric, etc. to be built as a separate subassembly and easily brought together for final assembly. The two structural layers are reinforced with bridging that adds strength and also permits firm attachment of plumbing pipes and other systems to the wall frame.
Date: December 31, 1997
Creator: Wendt, Robert; Lundell, Clark & Lau, Tin Man
Partner: UNT Libraries Government Documents Department

A Modular Approach to Redundant Robot Control

Description: This paper describes a modular approach for computing redundant robot kinematics. First some conventional redundant control methods are presented and shown to be `passive control laws`, i.e. they can be represented by a network consisting of passive elements. These networks are then put into modular form by applying scattering operator techniques. Additional subnetwork modules can then be added to further shape the motion. Modules for obstacle detection, joint limit avoidance, proximity sensing, and for imposing nonlinear velocity constraints are presented. The resulting redundant robot control system is modular, flexible and robust.
Date: December 1, 1997
Creator: Anderson, R.J.
Partner: UNT Libraries Government Documents Department

Secondary Containment Design for a High Speed Centrifuge

Description: Secondary containment for high speed rotating machinery, such as a centrifuge, is extremely important for operating personnel safety. Containment techniques can be very costly, ungainly and time consuming to construct. A novel containment concept is introduced which is fabricated out of modular sections of polycarbonate glazed into a Unistrut metal frame. A containment study for a high speed centrifuge is performed which includes the development of parameters for secondary containment design. The Unistrut/polycarbonate shield framing concept is presented including design details and proof testing procedures. The economical fabrication and modularity of the design indicates a usefulness for this shielding system in a wide variety of containment scenarios.
Date: March 1, 1999
Creator: Snyder, K.W.
Partner: UNT Libraries Government Documents Department

A zero-length bellows for the PEP-II High-Energy Ring

Description: Due to the beamline space constrictions and the modular design of the vacuum system, a conventional bellows can not be used everywhere in the PEP-II High-Energy Ring (HER) arcs. A zero-length ``Flex Flange`` was developed which actually performs better than a more standard bellows. The Flex Flange fits the space available while still preserving the modularity of the system. Furthermore, the design provides for an accurate match-up between adjoining octagonal copper chambers despite the large fabrication and assembly tolerances and high operational loads. Beam chamber continuity is ensured by an integral RF seal ring which is easy to install and fault-tolerant. Heating from synchrotron radiation and higher-order mode trapping is managed to ensure a robust connection despite the 3,000 mA beam current of the PEP-II HER. The Flex Flange concept is versatile and adaptable to many applications, yet economical both in space needed and cost.
Date: August 1, 1995
Creator: Nordby, M.; Daly, E.F.; Kurita, N. & Langton, J.
Partner: UNT Libraries Government Documents Department

Integrated Microsensors for Autonomous Microrobots

Description: This report describes the development of a miniature mobile microrobot device and several microsystems needed to create a miniature microsensor delivery platform. This work was funded under LDRD No.10785, entitled, ''Integrated Microsensors for Autonomous Microrobots''. The approach adopted in this project was to develop a mobile platform, to which would be attached wireless RF remote control and data acquisition in addition to various microsensors. A modular approach was used to produce a versatile microrobot platform and reduce power consumption and physical size.
Date: February 1, 2003
Partner: UNT Libraries Government Documents Department


Description: The United States Department of Energy (DOE) Complexes perform numerous hazardous material handling operations within the confines of a glovebox. The DOE is continuing to seek more efficient and safer means of handling these materials inside gloveboxes rather than the conventional, labor-intensive method through lead lined gloves. The use of glovebox automation technology will also be critical to the DOE in its efforts to comply with its mandated ALARA principles in handling the hazardous materials associated with the cleanup process. Operations associated with materials processing in a glovebox are similar to many industrial tasks, but the unique glovebox environment and Plutonium material properties create a unique set of challenges for conventional automation machinery. Such properties include: Low to moderate levels of ionizing radiation, high abrasiveness, corrosiveness, pyrophoric tendencies, rapid dispersal and permeation of environment, diffuses quickly, and possible incompatible material interaction. The glovebox presents the following challenges: existing gloveboxes may not be readily altered or even modified at all, complex mechanical operations for maintenance and repair are difficult or impossible through gloves, failed equipment may not be removed easily or at all. If a broken piece of equipment cannot be bagged-out through a glove port (approximately 216 mm (8 1/2 inch) diameter) it must remain in place. Broken equipment obstructs further operations. If it renders the entire glovebox unusable, a significant volume of waste is generated and an expensive system must be disposed of and replaced. A moderate sized glovebox alone costs between $250,000 and $500,000 and an equipment malfunction, which penetrates the glovebox and exposes the room to Plutonium or other toxic materials, is catastrophic. In addition to the human exposure issues, cleanup can easily run into the millions of dollars. A solution to the issues described above is ARM Automation Inc.'s (ARM) modular robotic manipulator technology developed for ...
Date: July 1, 2001
Partner: UNT Libraries Government Documents Department

Research on a Reconfigurable Modular Manipulator System. Final report, June 15, 1989--August 14, 1992

Description: Research has been conducted on developing the theoretical basis and the technology for a Reconfigurable Modular Manipulation System (RMMS). Unlike a conventional manipulator which has a fixed configuration, the RMMS consists of a set of interchangeable modules that can be rapidly assembled into a system of manipulators with appropriate configurations depending on the specific task requirement. For effective development and use of such a versatile and flexible system a program of theoretical and experimental research has been pursued aimed at developing the basis for next generation of autonomous manipulator systems. The RMMS concept extends the idea of autonomy from sensor-based to configuration based autonomy. One of the important components is the development of design methodologies for mapping tasks into manipulator configurations and for automatic generation of manipulator specific algorithms (e.g., kinematics and dynamics) in order to make the hardware transparent to the user.(JDB)
Date: August 1, 1992
Creator: Khosla, P. K. & Kanade, T.
Partner: UNT Libraries Government Documents Department

Graphite criteria peer review

Description: This report documents a review of the stress criteria proposed for the graphite components of the modular high temperature gas-cooled reactor (MHTGR) core. The review was conducted by a panel of six independent consultants, chosen for their expertise over a range of relevant disciplines.
Date: September 1, 1986
Partner: UNT Libraries Government Documents Department

Development of a photovoltaic module energy ratings methodology

Description: The National Renewable Energy Laboratory has begun work on developing a consensus-based approach to rating photovoltaic modules. This new approach was intended to address the limitations of the defacto standard module power rating at standard test conditions. Using technical input from a number of sources, and under the guidance of an industry-based technical review committee, the approach described in this paper was developed. The Module Energy Rating (MER) consists of 10 estimates of how much energy a single typical module of a particular type will produce in one day, one for each of 5 different weather/location combinations and 2 load-types. This paper presents an overview of the procedures required to generate an MER for any particular module type.
Date: May 1, 1995
Creator: Kroposki, B.; Mrig, L.; Whitaker, C. & Newmiller, J.
Partner: UNT Libraries Government Documents Department

Task 3.12 - small power systems. Semi-annual report, July 1, 1997--December 31, 1997

Description: One of the overall goals of the U.S. Department of Energy (DOE) is the development of the technology necessary to provide for a secure, reliable, affordable, and environmentally sound source of energy. This technology is important to ensure economic stability and growth in the next century as well as to reduce current and minimize future environmental impacts associated with power generation in the United States and the world. Throughout the world, coal will play an expanded role in the production of affordable energy necessary to meet the demands of economic development and growth. The development of more efficient and environmentally sound technology in the United States may present export market opportunities throughout the world. For coal to play a key role in the energy mix, it will be necessary to develop and commercialize technologies capable of producing electricity at significantly higher overall system efficiencies with minimum emissions. The programmatic goal in advanced power systems will be to develop small power systems in the range of 20 kW to 20 MW in cooperation with commercial vendors. These systems will be designed to incorporate the advanced technical capabilities of the Energy & Environmental Research Center (EERC) with the latest advancement in vendor-offered hardware and software. Work during this program year has focused on developing an integrated modular support system (IMSS) for small communities. A concept has been developed along with an approach for demonstrating an IMSS. Some of the constraints that must be overcome before the concept can be fully commercialized have also been identified and are presented here. This modular approach uses new and existing technologies to provide waste disposal, water supply treatment, and/or power generation capabilities on a scale appropriate to the situation.
Date: December 31, 1998
Creator: Mann, M.D.; Mayer, G.D. & Stepan, D.J.
Partner: UNT Libraries Government Documents Department

Development of a modular, bi-directional power inverter for photovoltaic applications. Annual technical progress report, August 1995--August 1996

Description: The goal of this research and development contract is to develop and prototype for manufacturing a modular, bi-directional power inverter for photovoltaic applications. This modular inverter will be used as building block for larger inverters by connecting in parallel (for higher power) or in series (for higher AC voltage) or both. The modular inverter will be capable of being interconnected for single, split and three phase configurations for both 60 hertz (domestic) and 50 hertz (international) applications. The design will also construction of units with different DC input voltages and AC output voltages to further satisfy various application and market requirements. By standardizing on a single {open_quotes}building block{close_quotes} inverter module, the need to build multiple models and sizes for different application can be avoided. The higher volume of a single design will allow improved manufacturing and will result in higher reliability by reducing low volume will allow improved manufacturing will result in higher reliability by reducing low volume modifications. The result will be lower cost and improved performance of photovoltaic systems.
Date: August 1, 1997
Creator: Freitas, C.
Partner: UNT Libraries Government Documents Department

Helical post stellarator. Part 1: Vacuum configuration

Description: Results on a novel type of stellarator configuration, the Helical Post Stellarator (HPS), are presented. This configuration is different significantly from all previously known stellarators due to its unique geometrical characteristics and unique physical properties. Among those are: the magnetic field has only one toroidal period (M = 1), the plasma has an extremely low aspect ratio, A {approx} 1, and the variation of the magnetic field, B, along field lines features a helical ripple on the inside of the torus. Among the main advantages of a HPS for a fusion program are extremely compact, modular, and simple design compatible with significant rotational transform, large plasma volume, and improved particle transport characteristics.
Date: August 1, 1997
Creator: Moroz, P.E.
Partner: UNT Libraries Government Documents Department

Upgrading Forms 3.0 to the Web using Developer/2000 1.4W

Description: The Monitoring Systems Technology Center (MSTC) at Sandia National Laboratories has recently upgraded its Satellite Parts Inventory Forms 3.0 application to Developer/2000 for the web. This involved changing from a character based Forms 3.0 system on an HP-UX 9000 database and forms server to a GUI forms 4.5 web- based system on Windows NT 4.0 Forms Serve. The need to migrate the MSTC Satellite Parts Inventory System to a newer supported software environment, that was easy to access and use, and was year 2000 compliant, drove the migration from forms 3.0. This paper will examine the steps of this successful migration to a web environment in detail. The MSTC Satellite Parts Inventory System includes a parts inventory application for inventory management of flight qualified electronic parts. This application tracks parts from receipt to fabrication, including manufacturer information such as lot and date, and quantities data such as lot totals, quantity on order and reorder levels. The system keeps a current count of parts that are used in kitting modules/assemblies for fabrication, does automated picks of the oldest parts, and allows suggested parts to be pulled or put back in stock and the required part pulled in place of the system suggested part. The system also flags and notifies component engineers of parts that fall below a certain level and includes traceability of parts to module record of assembly (ROA), module ROA repairs, drawings definition, CAD queue scheduling, purchase requisition records, and module action and document management.
Date: November 1, 1997
Creator: Campbell, D. & Martinez, R.
Partner: UNT Libraries Government Documents Department

ImBuild: Impact of building energy efficiency programs

Description: As part of measuring the impact of government programs on improving the energy efficiency of the Nation`s building stock, the Department of Energy Office of Building Technology, State and Community Programs (BTS) is interested in assessing the economic impacts of its portfolio of programs, specifically the potential impact on national employment and income. The special-purpose version of the IMPLAN model used in this study is called ImBuild. In comparison with simple economic multiplier approaches, such as Department of Commerce RIMS 2 system, ImBuild allows for more complete and automated analysis of the economic impacts of energy efficiency investments in buildings. ImBuild is also easier to use than existing macroeconomic simulation models. The authors conducted an analysis of three sample BTS energy programs: the residential generator-absorber heat exchange gas heat pump (GAX heat pump), the low power sulfur lamp (LPSL) in residential and commercial applications, and the Building America program. The GAX heat pump would address the market for the high-efficiency residential combined heating and cooling systems. The LPSL would replace some highly efficient fluorescent commercial lighting. Building America seeks to improve the energy efficiency of new factory-built, modular, manufactured, and small-volume, site-built homes through use of systems engineering concepts and early incorporation of new products and processes, and by increasing the demand for more energy-efficient homes. The authors analyze a scenario for market penetration of each of these technologies devised for BTS programs reported in the BTS GPRA Metrics Estimates, FY99 Budget Request, December 19, 1997. 46 figs., 4 tabs.
Date: April 1, 1998
Creator: Scott, M.J.; Hostick, D.J. & Belzer, D.B.
Partner: UNT Libraries Government Documents Department

Design of the Atlas 240 kV Marx modules

Description: A prototype 240 kV, oil-insulated Marx module has been designed and constructed at the Los Alamos National Laboratory (LANL). The prototype will be used for testing and certifying the design of the Marx module and certain components, including the closing switches, series resistor, and the capacitors themselves. The prototype will also be used to evaluate proposed mechanical systems designs. Information gained from the construction and testing of the 4-capacitor prototype will be folded into the design of the 16-capacitor maintenance unit. The prototype module consists of four 60 kV capacitors, two closing switches, one shunt resistor, and one series resistor. Cables are used to deliver the current to a dummy load scaled to match Atlas system parameters. The Marx unit is contained in a structure made from G-10, suspended from a steel frame that also serves to support components of the trigger, charging, and control system. Appropriate safety and charging systems are an integral part of the prototype design.
Date: June 1, 1997
Creator: Bowman, D.W.; Bennett, G. & Biehl, F.
Partner: UNT Libraries Government Documents Department