WorldWideScience

Sample records for technology paths agtsr

  1. The AGTSR consortium: An update

    Energy Technology Data Exchange (ETDEWEB)

    Fant, D.B.; Golan, L.P. [Clemson Univ., SC (United States)

    1995-10-01

    The Advanced Gas Turbine Systems Research (AGTSR) program is a collaborative University-Industry R&D Consortium that is managed and administered by the South Carolina Energy R&D Center. AGTSR is a nationwide consortium dedicated to advancing land-based gas turbine systems for improving future power generation capability. It directly supports the technology-research arm of the ATS program and targets industry-defined research needs in the areas of combustion, heat transfer, materials, aerodynamics, controls, alternative fuels, and advanced cycles. The consortium is organized to enhance U.S. competitiveness through close collaboration with universities, government, and industry at the R&D level. AGTSR is just finishing its third year of operation and is sponsored by the U.S. DOE - Morgantown Energy Technology Center. The program is scheduled to continue past the year 2000. At present, there are 78 performing member universities representing 36 states, and six cost-sharing U.S. gas turbine corporations. Three RFP`s have been announced and the fourth RFP is expected to be released in December, 1995. There are 31 research subcontracts underway at performing member universities. AGTSR has also organized three workshops, two in combustion and one in heat transfer. A materials workshop is in planning and is scheduled for February, 1996. An industrial internship program was initiated this past summer, with one intern positioned at each of the sponsoring companies. The AGTSR consortium nurtures close industry-university-government collaboration to enhance synergism and the transition of research results, accelerate and promote evolutionary-revolutionary R&D, and strives to keep a prominent U.S. industry strong and on top well into the 21st century. This paper will present the objectives and benefits of the AGTSR program, progress achieved to date, and future planned activity in fiscal year 1996.

  2. Overview of Allison/AGTSR interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S.A. [Allison Engine Co., Indianapolis, IN (United States)

    1995-10-01

    Morgantown Energy Technology Center`s Tom Bechtel`s perseverance resulted in the creation of the Advanced Gas Turbine Systems Research (AGTSR) initiative in 1992. His foresight resulted in establishing an advanced gas turbine research center. The center is supported by the Government and industry. The industry serves in an oversight role, and helps select the type of research projects to be conducted by universities. AGTSR now represents an effective university and industry partnership, and is recognized as a positive mechanism. Allison Engine Company (Allison) continues to be an active participant and a strong supporter of the Advanced Gas Turbine Systems Research initiative at Clemson University. Allison took part in early formulation stages of this university/industry consortium. We have been a member of the consortium since its inception in 1992. Allison`s senior management is cognizant of the benefits of these jointly sponsored research programs. Over the years, Allison has promoted cooperative gas turbine research and advanced technology development at many universities. This activity is conducted through direct assignments at Allison for university students, and support of research projects at various universities, focused on different disciplines of gas turbine research.

  3. Gas-path seal technology

    Science.gov (United States)

    Zuk, J.

    1976-01-01

    Improved gas-path seals are needed for better fuel economy, longer performance retention, and lower maintenance, particularly in advanced, high-performance gas turbine engines. Problems encountered in gas-path sealing are described, as well as new blade-tip sealing approaches for high-pressure compressors and turbines. These include a lubricant coating for conventional, porous-metal, rub-strip materials used in compressors. An improved hot-press metal alloy shows promise to increase the operating surface temperatures of high-pressure-turbine, blade-tip seals to 1450 K (2150 F). Three ceramic seal materials are also described that have the potential to allow much higher gas-path surface operating temperatures than are possible with metal systems.

  4. Technological opportunities and paths of development

    DEFF Research Database (Denmark)

    Plichta, Kirsten

    1993-01-01

    in the industry. 6) It is argued that such paths of incremental improvement at the industry level may be an outcome of a) the dynamics that produce the technological opportunities; b) the institutions that govern decisions and expectations and c) the criteria by which the chooses between different firms......Executive summary: 1) The technological development of firms in an industry is influenced by the opportunities for improving product and process, their ability to identify such opportunities and their ability to appropriate the benefit of the development effort. 2) Firms' historically developed...... technological knowledge, their production, development and other routines as well prior investments in products and production equipment play an important role with regard to the technological opportunities that firms' identify and select for development. 3) Because history matters and because firms are bounded...

  5. Solar technologies and the soft path: an empirical examination

    Energy Technology Data Exchange (ETDEWEB)

    Lodwick, D.G.

    1987-01-01

    A US national probability sample of 2023 traditional energy users and a purposive sample of 3809 solar energy technology owners are compared to assess whether those who owned solar energy technologies in 1980 have more soft path preferences (SPP) (e.g., attitudes and behaviors compatible with soft energy path developments) than do those who did not own such technologies. It is suggested that SPP is a necessary but not sufficient condition for the social structural transformation of society to the soft energy path proposed by Amory Lovins. A soft-path preferences scale is developed. The scale values for solar and nonsolar homeowners, for active and passive solar technology owners, and for those owing the technologies for four different time periods are compared. The nonsolar homeowners, passive technology owners, and those who owned the technologies from one to five years have the highest SPP scores. The greatest differences were found in the dimension of natural resources conservation. Partial least squares structural equation modeling is used to examine an extension and specification of Lovins' theory of soft-energy-path development. A model is created which focuses on the process of SPP development. Energy vulnerability needs, contextual resources, type of solar technologies, technological problems, and evaluation are the independent variables of the model.

  6. A technology path to distributed remote sensing

    Science.gov (United States)

    Fountain, Glen H.; Gold, Robert E.; Jenkins, Robert E.; Lew, Ark L.; Raney, R. Keith

    2000-03-01

    The Johns Hopkins University Applied Physics Laboratory (APL) has been engaged for over 40 years in Earth science missions spanning geodesy to atmospheric science. In parallel, APL's Advanced Technology Program is supporting research in autonomy, scalable architectures, miniaturization, and instrument innovation. These are key technologies for the development of affordable observation programs that could benefit from distributed remote sensing. This paper brings these applications and technology themes together in the form of an innovative, three-satellite remote sensing scenario. This pathfinding mission fills an important scientific niche, and relies on state-of-the-art small-satellite technology.

  7. Path dependence in technologies and organizations: a concise guide

    OpenAIRE

    Castaldi, C Carolina; Dosi, G; Paraskevopoulou, E

    2011-01-01

    The note on which an entry for the Palgrave Encyclopedia of Strategic Management will draw offers a beginner's guide to path dependency in technologies and organizations. We address the very meaning of the concept and its centrality in various aspects of economic analysis. We outline the various levels of the ecomic system in which it is observable, its sources, concequences and different formal representations of path dependent processes.

  8. Development Path for Agricultural Modernization of Shaanxi Province from the Perspective of Technological Progress

    Institute of Scientific and Technical Information of China (English)

    Lufeng; DUAN

    2013-01-01

    The lag in technological innovation is a bottleneck for modern agricultural development,so technological progress is an inevitable path to break this bottleneck. On the basis of introducing theory of technological progress,this study presents 4 paths for promoting agricultural modernization development in line with current situations of agricultural development and technological progress in Shaanxi Province.

  9. Evolution path of MWS technologies: RF, IR, and UV

    Science.gov (United States)

    Tidhar, Gil; Schlisselberg, Raanan

    2005-05-01

    In recent years some major technological developments in the fields of electro-optics and computer H/W took place, which call for reconsideration of the development paths for missile warning systems (MWS). In this work, we provide a review of the technological developments, and then suggest a framework for the following issues: (a) Prioritization of requirements for MWS, (b) Selection of best candidate technologies for next-generation MWS, (c) Establishing a generic parameter sensitivity model for MWS performance, with which we could quantify the effects of different design choices on system-level performance. Our work shows that (a) Infrared optical H/W remains the leading technology for MWS applications, (b) 3rd generation infrared imaging H/W will make a significant impact on MWS performance, compared with 2nd generation based IR-MWS system's performance. (c) Dual band infrared sensor FPAs now under development will further improve performance, yet the improvement will be offset by the lack of some of the more important features of the 3rd generation imagers-very high resolution and frame rate (d) A combination of 3rd generation and dual band IR imaging, when it becomes available, will provide yet another significant improvement.

  10. Technology Paths in Energy-Efficient and Sustainable Construction

    DEFF Research Database (Denmark)

    2015-01-01

    Various tehcnology paths and regimes, Building codes and standards in energy, eco and sustainable housing......Various tehcnology paths and regimes, Building codes and standards in energy, eco and sustainable housing...

  11. A Technological Primrose Path? ESL Students and Computer-Assisted Writing Programs.

    Science.gov (United States)

    Sampson, Donald E; and Gregory, James F.

    1991-01-01

    Describes what happened when students, unsupervised, used a style-checking computer program to check their essays. The feedback (considered somewhat misleading) suggested that teachers need to guide students along the technological path. (seven references) (GLR)

  12. Next Generation Nuclear Plant Project Technology Development Roadmaps: The Technical Path Forward

    Energy Technology Data Exchange (ETDEWEB)

    John Collins

    2009-01-01

    This document presents the Next Generation Nuclear Plant (NGNP) Systems, Subsystems, and Components, establishes a baseline for the current technology readiness status, and provides a path forward to achieve increasing levels of technical maturity.

  13. An Investigation of Factors Influencing Student Use of Technology in K-12 Classrooms Using Path Analysis

    Science.gov (United States)

    Ritzhaupt, Albert D.; Dawson, Kara; Cavanaugh, Cathy

    2012-01-01

    The purpose of this research was to examine the effects of teachers' characteristics, school characteristics, and contextual characteristics on classroom technology integration and teacher use of technology as mediators of student use of technology. A research-based path model was designed and tested based on data gathered from 732 teachers from…

  14. An Investigation of Factors Influencing Student Use of Technology in K-12 Classrooms Using Path Analysis

    Science.gov (United States)

    Ritzhaupt, Albert D.; Dawson, Kara; Cavanaugh, Cathy

    2012-01-01

    The purpose of this research was to examine the effects of teachers' characteristics, school characteristics, and contextual characteristics on classroom technology integration and teacher use of technology as mediators of student use of technology. A research-based path model was designed and tested based on data gathered from 732 teachers from…

  15. Tracing Technological Development Trajectories: A Genetic Knowledge Persistence-Based Main Path Approach.

    Science.gov (United States)

    Park, Hyunseok; Magee, Christopher L

    2017-01-01

    The aim of this paper is to propose a new method to identify main paths in a technological domain using patent citations. Previous approaches for using main path analysis have greatly improved our understanding of actual technological trajectories but nonetheless have some limitations. They have high potential to miss some dominant patents from the identified main paths; nonetheless, the high network complexity of their main paths makes qualitative tracing of trajectories problematic. The proposed method searches backward and forward paths from the high-persistence patents which are identified based on a standard genetic knowledge persistence algorithm. We tested the new method by applying it to the desalination and the solar photovoltaic domains and compared the results to output from the same domains using a prior method. The empirical results show that the proposed method can dramatically reduce network complexity without missing any dominantly important patents. The main paths identified by our approach for two test cases are almost 10x less complex than the main paths identified by the existing approach. The proposed approach identifies all dominantly important patents on the main paths, but the main paths identified by the existing approach miss about 20% of dominantly important patents.

  16. Path creation in Nordic energy and road transport systems – The role of technological characteristics

    DEFF Research Database (Denmark)

    Hansen, Teis; Klitkou, Antje; Borup, Mads;

    2017-01-01

    This paper reviews path-creation processes in road transport systems in the Nordic countries: e-mobility in Denmark, hydrogen and fuel-cell electrical vehicles in Norway, and advanced biofuels in Finland and Sweden. The study builds on the path creation literature, which seeks to explain the emer......This paper reviews path-creation processes in road transport systems in the Nordic countries: e-mobility in Denmark, hydrogen and fuel-cell electrical vehicles in Norway, and advanced biofuels in Finland and Sweden. The study builds on the path creation literature, which seeks to explain...... characteristics seem to have greater influence on the content of activities in the later phase rather than the early phase of path creation processes. The analysis also emphasises that barriers to path creation processes differ depending on technological characteristics. This highlights the importance...

  17. Technological challenges on the path to discovery in astrophysics

    Science.gov (United States)

    Perez, Mario R.

    2016-05-01

    Over the next decade, NASA's Astrophysics Division expects to undertake robotic or unmanned space flight missions that will explore the nature of the universe at its largest scales, its earliest moments, and its most extreme conditions. Current innovative and maturation technology programs are being conducted by NASA's Astrophysics Division to fill the technology gaps identified by the community. One of these efforts was to establish the Strategic Astrophysics Technology (SAT) program to support the maturation of key technologies. In this paper, these technology programs are described; in particular the SAT program will be presented describing the process to establish priorities, the technology management components, and the efforts to move these technologies into mission concepts and flight missions. The technology roadmap for a large mission concept such as ATLAST is presented as an example of the technology gaps derived and identified from these analyses, which could focus future efforts and investment priorities. Finally, the NASA preparation for the next decade, which will study and mature four large mission concepts, is briefly outlined.

  18. Technologies and Species Transitions: Polanyi, on a Path to Posthumanity?

    Science.gov (United States)

    Doede, Robert

    2011-01-01

    Polanyi and Transhumanism both place technologies in pivotal roles in bringing about "Homo sapiens"' species transitions. The question is asked whether Polanyi's emphasis on the role of technology in "Homo sapiens"' rise out of mute beasthood indicates that he might have been inclined to embrace the Transhumanist vision of "Homo sapiens"'…

  19. Textile Technologies and Tissue Engineering: A Path Toward Organ Weaving.

    Science.gov (United States)

    Akbari, Mohsen; Tamayol, Ali; Bagherifard, Sara; Serex, Ludovic; Mostafalu, Pooria; Faramarzi, Negar; Mohammadi, Mohammad Hossein; Khademhosseini, Ali

    2016-04-06

    Textile technologies have recently attracted great attention as potential biofabrication tools for engineering tissue constructs. Using current textile technologies, fibrous structures can be designed and engineered to attain the required properties that are demanded by different tissue engineering applications. Several key parameters such as physiochemical characteristics of fibers, microarchitecture, and mechanical properties of the fabrics play important roles in the effective use of textile technologies in tissue engineering. This review summarizes the current advances in the manufacturing of biofunctional fibers. Different textile methods such as knitting, weaving, and braiding are discussed and their current applications in tissue engineering are highlighted.

  20. Constructive Science and Technology Studies: On the Path to Being?

    Science.gov (United States)

    Steiner, Carol J.

    1999-01-01

    Suggests that science and technology studies (STS) is ready to reconsider an approach based on Heideggerian phenomenology. Argues that STS is facing a confrontation with the inadequacies of constructivism's founding assumptions. (CCM)

  1. Hydrogen Education Curriculum Path at Michigan Technological University

    Energy Technology Data Exchange (ETDEWEB)

    Keith, Jason; Crowl, Daniel; Caspary, David; Naber, Jeff; Allen, Jeff; Mukerjee, Abhijit; Meng, Desheng; Lukowski, John; Solomon, Barry; Meldrum, Jay

    2012-01-03

    The objective of this project was four-fold. First, we developed new courses in alternative energy and hydrogen laboratory and update existing courses in fuel cells. Secondly, we developed hydrogen technology degree programs. Thirdly, we developed hydrogen technology related course material for core courses in chemical engineering, mechanical engineering, and electrical engineering. Finally, we developed fuel cell subject material to supplement the Felder & Rousseau and the Geankoplis chemical engineering undergraduate textbooks.

  2. Binaural Beat Technology: A Complementary Path to Post Deployment Wellness

    Science.gov (United States)

    2017-03-16

    management of stress, not only for the patient but for the nurse as well. This technology is flexible , as it can be used at the bedside, in an outpatient...effect. Since the technology is marketed to the general public through venues such as YouTube, Apple App store, and Apple iTunes and is not FDA...Subjects Screened 191 Subjects Ineligible 74 Subjects Refused 43 Human Subjects Consented 74 Subjects Intervention Group / Control or Sham Group

  3. Smoothing the Path: Technology Education and School Transition

    Science.gov (United States)

    Mawson, Brent

    2003-08-01

    The lack of coherence between early childhood education settings and primary school classrooms provides a challenge to the creation of a seamless educational experience in the period from birth to age eight. This paper examines the nature of technological activities in Kindergartens and New Entrant/Year One classes in New Zealand. It highlights commonalities between the two and discusses the potential for technology education to provide a bridge for children to ease their passage into the formal school setting and to provide a coherent educational experience.

  4. Path of the progress of science and technology

    Energy Technology Data Exchange (ETDEWEB)

    Goloviznin, V.P. (Minehnergomash)

    1984-05-01

    Basic measures aimed at the progress of growth and more intensive production in the field of devising the NPP equipment are considered. A conclusion is drawn that the solution to the problems considered is related to further improvement of the system of planning, financing and material stimulation of works on new technology as well as to expansion of rights of research and industrial centers and institutes.

  5. Factors Affecting Technology Integration in K-12 Classrooms: A Path Model

    Science.gov (United States)

    Inan, Fethi A.; Lowther, Deborah L.

    2010-01-01

    The purpose of this study was to examine the direct and indirect effects of teachers' individual characteristics and perceptions of environmental factors that influence their technology integration in the classroom. A research-based path model was developed to explain causal relationships between these factors and was tested based on data gathered…

  6. Hybrid location determination technology within urban and indoor environment based on Cell-ID and path loss

    Institute of Scientific and Technical Information of China (English)

    HU Sheng; LEI Jian-jun; XIA Ying; GE Jun-wei; BAE Hae-young

    2004-01-01

    The location determination technology based on simple delay evaluations or GPS is not accurate enough or even impossible in urban and indoor environments due to the multi-path propagation. To enhance the location accuracy and reduce the operation cost within these environments, this paper proposes a novel hybrid location determination technology which combines CELL-ID with the database correlation method. The proposed method generate the prediction database of path loss according to CELL-ID, and after the computation the smallest squared error of measured path loss and the prediction path loss,the location of the mobile terminal is decided by the coordinates of the best matching matrix entry.

  7. Technological migration paths towards the smart grid; Technologische Migrationspfade in das Smart Grid

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Christoph; Daenekas, Christian [OFFIS - Institut fuer Informatik, Oldenburg (Germany); Breuer, Andreas [RWE Deutschland AG, Essen (Germany)] [and others

    2012-07-01

    The changes within the power system will lead to a new system architecture, which will be highly dependent on information and communication technologies (ICT) and is commonly referenced by the term ''Smart Grid''. While research and development efforts in this field have led to substantial progress regarding technological components, fewer approaches exist regarding the development of suitable migration paths leading to both a robust and innovative system. In this contribution a stepwise approach regarding the development of such migration paths is presented. At first scenarios for the year 2030 are created. These scenarios enable the identification of essential ICT related ''technology fields'' (TF) and their allocation to the power systems domains. For each TF the future levels of development progress and interdependencies are described. The joint analysis of scenarios, TF levels of development progress and interdependencies leads to a roadmap, describing the migration paths regarding the implementation of Smart Grids. Within this roadmap three phases are distinguished: the concept phase, the integration phase and the fusion phase. (orig.)

  8. Technology Exploitation Paths: Combining Technological and Complementary Resources in New Product Development and Licensing

    NARCIS (Netherlands)

    Bianchi, Mattia; Frattini, Frederico; Lejarraga, Jose; Di Minin, Alberto

    2014-01-01

    Technological resources in the form of patents, trade secrets, and know-how have become key assets for modern enterprises. This paper addresses a critical issue in technology and innovation management, namely, the commercial exploitation of technological resources resulting from research and

  9. Technology Exploitation Paths: Combining Technological and Complementary Resources in New Product Development and Licensing

    NARCIS (Netherlands)

    Bianchi, Mattia; Frattini, Frederico; Lejarraga, Jose; Di Minin, Alberto

    2014-01-01

    Technological resources in the form of patents, trade secrets, and know-how have become key assets for modern enterprises. This paper addresses a critical issue in technology and innovation management, namely, the commercial exploitation of technological resources resulting from research and develop

  10. Technology Exploitation Paths: Combining Technological and Complementary Resources in New Product Development and Licensing

    NARCIS (Netherlands)

    Bianchi, Mattia; Frattini, Frederico; Lejarraga, Jose; Di Minin, Alberto

    2014-01-01

    Technological resources in the form of patents, trade secrets, and know-how have become key assets for modern enterprises. This paper addresses a critical issue in technology and innovation management, namely, the commercial exploitation of technological resources resulting from research and develop

  11. International Diffusion of Open Path FTIR Technology and Air Monitoring Methods: Taiwan (Republic of China).

    Science.gov (United States)

    Giese-Bogdan, Stefan It; Levine, Steven P

    1996-08-01

    International cooperation and diffusion of environmental technologies is a central goal of the U.S. EPA Environmental Technology Initiative, and is of great interest to many countries. One objective is to exchange knowledge and skills concerning new monitoring technologies. In this case, the technology was open path Fourier Transform Infrared Spectrometry (op-FTIR). Taiwan is a high-technology, newly industrialized country. Because of air pollution problems, it is interested in obtaining skills, knowledge, and instrumentation for monitoring air pollutants. In April 1994, the Industrial Technology Research Institute, Center for Industrial Safety and Health Technology (ITRI/CISH) in Hsinchu, Taiwan, requested intensive training in op-FTIR. Training was held between September 30,1994 and October 29,1994. During the stay, the instructor provided intensive training on op-FTIR theory as well as an introduction to available instrumentation and software. The training concluded with a field demonstration of the instrumentation in a manufacturing facility. This report gives an overview of the training methods, structure, and materials in the op-FTIR training course. It will also address various problems encountered while teaching this course. In addition, the potential use for this technology in industry as well as by the Taiwanese government will be explained.

  12. Soft Energy Paths Revisited: Politics and Practice in Energy Technology Transitions

    Directory of Open Access Journals (Sweden)

    Chelsea Schelly

    2016-10-01

    Full Text Available This paper argues that current efforts to study and advocate for a change in energy technologies to reduce their climate and other environmental impacts often ignore the political, social, and bodily implications of energy technology choices. Framing renewable energy technologies exclusively in terms of their environmental benefits dismisses important questions about how energy infrastructures can be designed to correspond to democratic forms of socio-politics, forms of social organization that involve independence in terms of meeting energy needs, resilience in terms of adapting to change, participatory decision making and control, equitable distribution of knowledge and efficacy, and just distribution of ownership. Recognizing technological choices as political choices brings explicit attention to the kinds of socio-political restructuring that could be precipitated through a renewable energy technology transition. This paper argues that research on energy transitions should consider the political implications of technological choices, not just the environmental consequences. Further, emerging scholarship on energy practices suggests that social habits of energy usage are themselves political, in that they correspond to and reinforce particular arrangements of power. Acknowledging the embedded politics of technology, as the decades’ old concept of soft path technologies encourages, and integrating insights on the politics of technology with insights on technological practices, can improve future research on energy policy and public perceptions of energy systems. This paper extends insights regarding the socio-political implications of energy paths to consider how understandings of energy technologies as constellations of embedded bodily practices can help further develop our understanding of the consequences of energy technologies, consequences that move beyond environmental implications to the very habits and behaviors of patterned energy

  13. Paths of Improving the Technological Process of Manufacture of GTE Turbine Blades

    Science.gov (United States)

    Vdovin, R. A.; Smelov, V. G.; Bolotov, M. A.; Pronichev, N. D.

    2016-08-01

    The article provides an analysis of the problems at manufacture of blades of the turbine of gas-turbine engines and power stations is provided in article, and also paths of perfecting of technological process of manufacture of blades are offered. The analysis of the main systems of basing of blades in the course of machining and the control methods of the processed blades existing at the enterprises with the indication of merits and demerits is carried out. In work criteria in the form of the mathematical models of a spatial distribution of an allowance considering the uniform distribution of an allowance on a feather profile are developed. The considered methods allow to reduce percent of release of marriage and to reduce labor input when polishing path part of a feather of blades of the turbine.

  14. Searching for a Path: A Bibliometric study on Innovation and Technological Capabilities

    Directory of Open Access Journals (Sweden)

    João Heitor De Avila Santos

    2015-11-01

    Full Text Available Innovation is recognize as a matter of survival and success to firms and technological capabilities can lead to an innovative behavior by using technological resources and competences. The literature about technological capability and innovation is vast, counting on several approaches and a large number of researchers involved within. Based on this, our aim is to use a bibliometrics approach to map out the authors, institutions, journals and the evolution of the publication as well, to provide the path needed to build a theoretical framework about the theme. We held this research on the Scopus database using a standard search protocol to perform the selection of the sample. Our results indicates an emerging field of study and a large number papers and citations concentrated in few journals. Most cited authors are related to seminal works on the subject and most cited papers are ones from late 90’s and early 2000. 

  15. An Analysis of the Assembly Path Planning of Decelerator Based on Virtual Technology

    Science.gov (United States)

    Jin, Xiangyang; Zhang, Tiefeng; Yang, Hanlin

    According to structural features of different components of decelerator, the general rule of three-dimensional solid modeling of components is summarized, the three-dimensional model of gear stand is built, all components are organized into groups to form a whole partial assembly, and various kinds of assembly relations are added among components, as well as hierarchical relations. Then the assembly path of decelerator is programmed, the sequence of assembling components is decided, and finally the assembly simulation is completed, laying the foundation for component disassembly. Virtual assembly technology helps to introduce advanced design approaches, improve the quality of products, reduce development cost and shorten development cycle.

  16. Mobile Measurements of Methane Using High-Speed Open-Path Technology

    Science.gov (United States)

    Burba, G. G.; Anderson, T.; Ediger, K.; von Fischer, J.; Gioli, B.; Ham, J. M.; Hupp, J. R.; Kohnert, K.; Levy, P. E.; Polidori, A.; Pikelnaya, O.; Price, E.; Sachs, T.; Serafimovich, A.; Zondlo, M. A.; Zulueta, R. C.

    2016-12-01

    Methane plays a critical role in the radiation balance, chemistry of the atmosphere, and air quality. The major anthropogenic sources of CH4 include oil and gas development sites, natural gas distribution networks, landfill emissions, and agricultural production. The majority of oil and gas and urban CH4 emission occurs via variable-rate point sources or diffused spots in topographically challenging terrains (e.g., street tunnels, elevated locations at water treatment plants, vents, etc.). Locating and measuring such CH4 emissions is challenging when using traditional micrometeorological techniques, and requires development of novel approaches. Landfill CH4 emissions traditionally assessed at monthly or longer time intervals are subject to large uncertainties because of the snapshot nature of the measurements and the barometric pumping phenomenon. The majority of agricultural and natural CH4 production occurs in areas with little infrastructure or easily available grid power (e.g., rice fields, arctic and boreal wetlands, tropical mangroves, etc.). A lightweight, high-speed, high-resolution, open-path technology was recently developed for eddy covariance measurements of CH4 flux, with power consumption 30-150 times below other available technologies. It was designed to run on solar panels or a small generator and be placed in the middle of the methane-producing ecosystem without a need for grid power. Lately, this instrumentation has been utilized increasingly more frequently outside of the traditional use on stationary flux towers. These novel approaches include measurements from various moving platforms, such as cars, aircraft, and ships. Projects included mapping of concentrations and vertical profiles, leak detection and quantification, mobile emission detection from natural gas-powered cars, soil CH4 flux surveys, etc. This presentation will describe key projects utilizing the novel lightweight low-power high-resolution open-path technology, and will highlight

  17. A Path Analysis of Educator Perceptions of Open Educational Resources Using the Technology Acceptance Model

    Directory of Open Access Journals (Sweden)

    Hope Kelly

    2014-04-01

    Full Text Available Open educational resources (OER are making their way into a variety of educational contexts from formal lesson planning to just in time learning. Educators and training professionals have been recognized as an important audience for these materials. The concepts of self-efficacy and outcome judgment from social cognitive learning theory serve as theoretical constructs to measure educator perceptions of OER. This study uses a path analysis, based on the technology acceptance model, to understand adoption of these resources by this audience with a particular emphasis on self-efficacy. Among the participants, three main groups were identified: K-12 educators, higher education professionals, and those involved in workplace training. A discriminant function analysis found that K-12 educators stood out as finding OER relevant to improving their practice. Recommendations are made in regards to an emphasis on easy to use designs to improve application self-efficacy of OER and instructional messaging for future K-12 educators.

  18. Information technology - Telecommunications and information exchange between systems - Private integrated services network - Inter-exchange signalling protocol - Path replacement additional network feature

    CERN Document Server

    International Organization for Standardization. Geneva

    2003-01-01

    Information technology - Telecommunications and information exchange between systems - Private integrated services network - Inter-exchange signalling protocol - Path replacement additional network feature

  19. Latest on Mobile Methane Measurements with Fast Open-Path Technology: Experiences, Opportunities & Perspectives

    Science.gov (United States)

    Burba, George; Anderson, Tyler; Ediger, Kevin; von Fischer, Joseph; Gioli, Beniamino; Ham, Jay; Hupp, Jason; Kohnert, Katrin; Larmanou, Eric; Levy, Peter; Polidori, Andrea; Pikelnaya, Olga; Price, Eric; Sachs, Torsten; Serafimovich, Andrei; Zondlo, Mark; Zulueta, Rommel

    2016-04-01

    Methane plays a critical role in the radiation balance, chemistry of the atmosphere, and air quality. The major sources of methane include agricultural and natural production, landfill emissions, oil and gas development sites, and natural gas distribution networks in rural and urban environments. The majority of agricultural and natural methane production occurs in areas with little infrastructure or easily available grid power (e.g., rice fields, arctic and boreal wetlands, tropical mangroves, etc.) Past approaches for direct measurements of methane fluxes relied on fast closed-path analyzers, which typically require powerful pumps and grid power. Power and labor demands may be among the key reasons why such methane fluxes were often measured at locations with good infrastructure and grid power, and not necessarily with high methane production. Landfill methane emissions were traditionally assessed via point-in-time measurements taken at monthly or longer time intervals using techniques such as the trace plume method, the mass balance method, etc. These are subject to large uncertainties because of the snapshot nature of the measurements, while the changes in emission rates are continuous due to ongoing landfill development, changes in management practices, and the barometric pumping phenomenon. Installing a continuously operating flux station in the middle of an active landfill requires a low-power approach with no cables stretching across the landfill. The majority of oil and gas and urban methane emission happens via variable-rate point sources or diffused spots in topographically challenging terrains, such as street tunnels, elevated locations at water treatment plants, vents, etc. Locating and measuring methane emissions from such sources is challenging when using traditional micrometeorological techniques, and requires development of novel approaches. In 2010, a new lightweight high-speed high-resolution open-path technology was developed with the goal of

  20. The path-to-purchase is paved with digital opportunities: An inventory of shopper-oriented retail technologies

    OpenAIRE

    Willems, Kim; Smolders, Annelien; Brengman, Malaika; Luyten, Kris; Schöning, Johannes

    2016-01-01

    This study focuses on innovative ways to digitally instrument the servicescape in bricks-and-mortar retailing. In the present digital era, technological developments allow for augmenting the shopping experience and capturing moments-of-truth along the shopper's path-to-purchase. This article provides an encompassing inventory of retail technologies resulting from a systematic screening of three secondary data sources, over 2008–2016: (1) the academic marketing literature, (2) retailing relate...

  1. 技术创新路径锁定与解锁%Lock-in and Unlocking of Technological Innovation Path

    Institute of Scientific and Technical Information of China (English)

    王子龙; 许箫迪

    2012-01-01

    技术创新路径锁定是一个历史依赖过程,路径锁定的根本原因在于各类技术之间存在巨大转移成本和潜在不同市场均衡。报酬递增效应、自增强机制以及群体博弈均会影响到市场对技术的选择,这种选择会使技术发展陷入固定轨道。研究了技术创新路径锁定机理、锁定效应以及解锁模式,从提高参与人认知能力、改善外部环境、实施利益诱导和外部冲击四个方面提出实现技术创新解锁的途径。%The path lock-in of technological innovation is a dependence process of the history.The fundamental reason of the path lock-in is that existing transfer costs and potential different market equilibrium in all types of technology.Increasing returns effect,self strengthening mechanism and group game will be affecting the market choice of technology.This choice will make the technology development in a fixed orbit.The path lock-in mechanism,lock-in effect and unlocking pattern of technological innovation is systematically researched in this paper.The way of technical innovation unlocking is put forward from promoting participants cognitive ability,improving external environment,implementing benefit induction and external shocks.

  2. The automated system for technological process of spacecraft's waveguide paths soldering

    Science.gov (United States)

    Tynchenko, V. S.; Murygin, A. V.; Emilova, O. A.; Bocharov, A. N.; Laptenok, V. D.

    2016-11-01

    The paper solves the problem of automated process control of space vehicles waveguide paths soldering by means of induction heating. The peculiarities of the induction soldering process are analyzed and necessity of information-control system automation is identified. The developed automated system makes the control of the product heating process, by varying the power supplied to the inductor, on the basis of information about the soldering zone temperature, and stabilizing the temperature in a narrow range above the melting point of the solder but below the melting point of the waveguide. This allows the soldering process automating to improve the quality of the waveguides and eliminate burn-troughs. The article shows a block diagram of a software system consisting of five modules, and describes the main algorithm of its work. Also there is a description of the waveguide paths automated soldering system operation, for explaining the basic functions and limitations of the system. The developed software allows setting of the measurement equipment, setting and changing parameters of the soldering process, as well as view graphs of temperatures recorded by the system. There is shown the results of experimental studies that prove high quality of soldering process control and the system applicability to the tasks of automation.

  3. Measuring Methane from Cars, Ships, Airplanes, Helicopters and Drones Using High-Speed Open-Path Technology

    Science.gov (United States)

    Burba, George; Anderson, Tyler; Biraud, Sebastien; Caulton, Dana; von Fischer, Joe; Gioli, Beniamino; Hanson, Chad; Ham, Jay; Kohnert, Katrin; Larmanou, Eric; Levy, Peter; Polidori, Andrea; Pikelnaya, Olga; Sachs, Torsten; Serafimovich, Andrei; Zaldei, Alessandro; Zondlo, Mark; Zulueta, Rommel

    2017-04-01

    Methane plays a critical role in the radiation balance, chemistry of the atmosphere, and air quality. The major anthropogenic sources of methane include oil and gas development sites, natural gas distribution networks, landfill emissions, and agricultural production. The majority of oil and gas and urban methane emission occurs via variable-rate point sources or diffused spots in topographically challenging terrains (e.g., street tunnels, elevated locations at water treatment plants, vents, etc.). Locating and measuring such methane emissions is challenging when using traditional micrometeorological techniques, and requires development of novel approaches. Landfill methane emissions traditionally assessed at monthly or longer time intervals are subject to large uncertainties because of the snapshot nature of the measurements and the barometric pumping phenomenon. The majority of agricultural and natural methane production occurs in areas with little infrastructure or easily available grid power (e.g., rice fields, arctic and boreal wetlands, tropical mangroves, etc.). A lightweight, high-speed, high-resolution, open-path technology was recently developed for eddy covariance measurements of methane flux, with power consumption 30-150 times below other available technologies. It was designed to run on solar panels or a small generator and be placed in the middle of the methane-producing ecosystem without a need for grid power. Lately, this instrumentation has been utilized increasingly more frequently outside of the traditional use on stationary flux towers. These novel approaches include measurements from various moving platforms, such as cars, aircraft, and ships. Projects included mapping of concentrations and vertical profiles, leak detection and quantification, mobile emission detection from natural gas-powered cars, soil methane flux surveys, etc. This presentation will describe the latest state of the key projects utilizing the novel lightweight low-power high

  4. Application of structural health monitoring technologies to bio-systems: current status and path forward

    Science.gov (United States)

    Bhalla, Suresh; Srivastava, Shashank; Suresh, Rupali; Moharana, Sumedha; Kaur, Naveet; Gupta, Ashok

    2015-03-01

    This paper presents a case for extension of structural health monitoring (SHM) technologies to offer solutions for biomedical problems. SHM research has made remarkable progress during the last two/ three decades. These technologies are now being extended for possible applications in the bio-medical field. Especially, smart materials, such as piezoelectric ceramic (PZT) patches and fibre-Bragg grating (FBG) sensors, offer a new set of possibilities to the bio-medical community to augment their conventional set of sensors, tools and equipment. The paper presents some of the recent extensions of SHM, such as condition monitoring of bones, monitoring of dental implant post surgery and foot pressure measurement. Latest developments, such as non-bonded configuration of PZT patches for monitoring bones and possible applications in osteoporosis detection, are also discussed. In essence, there is a whole new gamut of new possibilities for SHM technologies making their foray into the bi-medical sector.

  5. A Path Model of Effective Technology-Intensive Inquiry-Based Learning

    Science.gov (United States)

    Avsec, Stanislav; Kocijancic, Slavko

    2016-01-01

    Individual aptitude, attitudes, and behavior in inquiry-based learning (IBL) settings may affect work and learning performance outcomes during activities using different technologies. To encourage multifaceted learning, factors in IBL settings must be statistically significant and effective, and not cognitively or psychomotor intensive. We…

  6. The city in the information and communication technology age: a comparative study on path dependecy

    NARCIS (Netherlands)

    Jonkhoff, Wouter; Nijkamp, Peter

    2001-01-01

    The role of the city in the modem electronic age is rapidly changing. Cities are no longer closed islands of local opportunities, but are open nodalpoints in a global network environment. The Information and Communication Technology (ICT) has lifted the traditional physical - geographicalconstraints

  7. Academic Technology and the Future of Higher Education: Strategic Paths Taken and Not Taken.

    Science.gov (United States)

    Privateer, Paul Michael

    1999-01-01

    If American colleges and universities are to become contemporary and effective organizations, their strategic academic-technology agenda should be focused on production of intelligence rather than on storage and recall of random and quickly outmoded information. Institutions must articulate a new mythology based on new connections between…

  8. A Path Model of Effective Technology-Intensive Inquiry-Based Learning

    Science.gov (United States)

    Avsec, Stanislav; Kocijancic, Slavko

    2016-01-01

    Individual aptitude, attitudes, and behavior in inquiry-based learning (IBL) settings may affect work and learning performance outcomes during activities using different technologies. To encourage multifaceted learning, factors in IBL settings must be statistically significant and effective, and not cognitively or psychomotor intensive. We…

  9. The path to the future: The role of science and technology at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Reck, R.A.

    1996-04-30

    Today some scientists are concerned that present budget considerations in Washington will make it impossible for the US to maintain its preeminence in important areas of science and technology. In the private sector there has been a demise of substantive R & D efforts through most of the major industries. For DOE a lack of future support for science and technology would be an important issue because this could impact DOE`s abilities to solve problems in its major areas of concern, national security, energy, environment. In fact some scientists maintain that were the present trend to continue unabated it could lead to a national security issue. Preeminence in science and technology plays a critical role in our nation`s position as the leader of world democracy. In contrast with this point of view of gloom and doom, however, in this presentation I hope to bring to you what I see as an exciting message of good news. Today I will list the important opportunities and challenges for the future that I note for ANL, the leadership role that I believe ANL can play and the qualities that will help our laboratory to maintain its status as an outstanding DOE National Laboratory.

  10. Advanced technology paths to global climate stability: energy for a greenhouse planet.

    Science.gov (United States)

    Hoffert, Martin I; Caldeira, Ken; Benford, Gregory; Criswell, David R; Green, Christopher; Herzog, Howard; Jain, Atul K; Kheshgi, Haroon S; Lackner, Klaus S; Lewis, John S; Lightfoot, H Douglas; Manheimer, Wallace; Mankins, John C; Mauel, Michael E; Perkins, L John; Schlesinger, Michael E; Volk, Tyler; Wigley, Tom M L

    2002-11-01

    Stabilizing the carbon dioxide-induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (approximately 10(13) watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission-free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non-primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development.

  11. On the Path to SunShot - Advancing Concentrating Solar Power Technology, Performance, and Dispatchability

    Energy Technology Data Exchange (ETDEWEB)

    Mehos, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ho, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-05-01

    Energy storage will help enable CSP compete by adding flexibility value to a high-variable-generation (solar plus wind) power system (see Mehos et al. 2016). Compared with PV, CSP systems are more complex to develop, design, construct, and operate, and they require a much larger minimum effective scale—typically at least 50 MW, compared with PV systems that can be as small as a few kilowatts. In recent years, PV’s greater modularity and lower LCOE have made it more attractive to many solar project developers, and some large projects that were originally planned for CSP have switched to PV. However, the ability of CSP to use thermal energy storage—and thus provide continuous power for long periods when the sun is not shining—could give CSP a vital role in evolving electricity systems. Because CSP with storage can store energy when net demand is low and release that energy when demand is high, it increases the electricity system’s ability to balance supply and demand over multiple time scales. Such flexibility becomes increasingly important as more variable-generation renewable energy is added to the system. For example, one analysis suggests that, under a 40% renewable portfolio standard in California, CSP with storage could provide more than twice as much value to the electricity system as variable-generation PV. For this reason, enhanced thermal energy storage is a critical component of the SunShot Initiative’s 2020 CSP technology-improvement roadmap.

  12. Next Generation Nuclear Plant Project Technology Development Roadmaps: The Technical Path Forward for 750–800°C Reactor Outlet Temperature

    Energy Technology Data Exchange (ETDEWEB)

    John Collins

    2009-08-01

    This document presents the NGNP Critical PASSCs and defines their technical maturation path through Technology Development Roadmaps (TDRMs) and their associated Technology Readiness Levels (TRLs). As the critical PASSCs advance through increasing levels of technical maturity, project risk is reduced and the likelihood of within-budget and on-schedule completion is enhanced. The current supplier-generated TRLs and TDRMs for a 750–800°C reactor outlet temperature (ROT) specific to each supplier are collected in Appendix A.

  13. On the Path to SunShot. Advancing Concentrating Solar Power Technology, Performance, and Dispatchability

    Energy Technology Data Exchange (ETDEWEB)

    Mehos, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Turchi, Craig [National Renewable Energy Lab. (NREL), Golden, CO (United States); Jorgenson, Jennie [National Renewable Energy Lab. (NREL), Golden, CO (United States); Denholm, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ho, Clifford [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-05-01

    This report examines the remaining challenges to achieving the competitive concentrating solar power (CSP) costs and large-scale deployment envisioned under the U.S. Department of Energy's SunShot Initiative. Although CSP costs continue to decline toward SunShot targets, CSP acceptance and deployment have been hindered by inexpensive photovoltaics (PV). However, a recent analysis found that thermal energy storage (TES) could increase CSP's value--based on combined operational and capacity benefits--by up to 6 cents/kWh compared to variable-generation PV, under a 40% renewable portfolio standard in California. Thus, the high grid value of CSP-TES must be considered when evaluating renewable energy options. An assessment of net system cost accounts for the difference between the costs of adding new generation and the avoided cost from displacing other resources providing the same level of energy and reliability. The net system costs of several CSP configurations are compared with the net system costs of conventional natural-gas-fired combustion-turbine (CT) and combined-cycle plants. At today's low natural gas prices and carbon emission costs, the economics suggest a peaking configuration for CSP. However, with high natural gas prices and emission costs, each of the CSP configurations compares favorably against the conventional alternatives, and systems with intermediate to high capacity factors become the preferred alternatives. Another analysis compares net system costs for three configurations of CSP versus PV with batteries and PV with CTs. Under current technology costs, the least-expensive option is a combination of PV and CTs. However, under future cost assumptions, the optimal configuration of CSP becomes the most cost-effective option.

  14. Triple-Pulse Integrated Path Differential Absorption Lidar for Carbon Dioxide Measurement - Novel Lidar Technologies and Techniques with Path to Space

    Science.gov (United States)

    Singh, Upendra N.; Refaat, Tamer F.; Petros, Mulugeta

    2017-01-01

    The societal benefits of understanding climate change through identification of global carbon dioxide sources and sinks led to the desired NASA's active sensing of carbon dioxide emissions over nights, days, and seasons (ASCENDS) space-based missions of global carbon dioxide measurements. For more than 15 years, NASA Langley Research Center (LaRC) have developed several carbon dioxide active remote sensors using the differential absorption lidar (DIAL) technique operating at the two-micron wavelength. Currently, an airborne two-micron triple-pulse integrated path differential absorption (IPDA) lidar is under development. This IPDA lidar measures carbon dioxide as well as water vapor, the dominant interfering molecule on carbon dioxide remote sensing. Advancement of this triple-pulse IPDA lidar development is presented.

  15. Absorption and metabolization of sex hormones and their transformation into contraceptive technologies: the paths taken by medical thought in Brazil.

    Science.gov (United States)

    Bonan, Claudia; Teixeira, Luiz Antonio; Nakano, Andreza Rodrigues

    2017-01-01

    The article analyses knowledge assimilation and the development of clinical and research practices relating to sex hormones among Brazilian gynaecologists. It discusses the paths taken by medical thought from the reception of the hormones to their transformation into contraceptives. Our objective is to comprehend styles of introducing and disseminating medical technologies in the area of reproductive health in Brazil. It uses methods of historical analysis and takes as its source the Anais Brasileiros de Ginecologia, a journal published between 1936 and 1970. From the outset, the accompaniment of scientific breakthroughs in relation to sex hormones and their use to treat diverse female illnesses played a key role in the rapid medical acceptance of hormonal contraception. Scientific and technical questions (side effects, dosages) and the demographic issue formed part of the majority of the debates. Objections from the Catholic Church were considered but did not set the agenda of medical thought on contraceptives. The quest to consolidate gynaecology as a scientific, modern and cosmopolitan area of expertise, along with sanitary and demographic motives that allowed contraceptives to be classed as ethical drugs, are identified as processes underlying the assimilation and metabolization of sex hormones as hormonal contraceptives.

  16. Path Dependency

    OpenAIRE

    Mark Setterfield

    2015-01-01

    Path dependency is defined, and three different specific concepts of path dependency – cumulative causation, lock in, and hysteresis – are analyzed. The relationships between path dependency and equilibrium, and path dependency and fundamental uncertainty are also discussed. Finally, a typology of dynamical systems is developed to clarify these relationships.

  17. The Use of Digital Technology in Finding Multiple Paths to Solve and Extend an Equilateral Triangle Task

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

    2016-01-01

    Mathematical tasks are crucial elements for teachers to orient, foster and assess students' processes to comprehend and develop mathematical knowledge. During the process of working and solving a task, searching for or discussing multiple solution paths becomes a powerful strategy for students to engage in mathematical thinking. A simple task that…

  18. [The Stability and Measuring Technology of the Maximum Optical Path Difference of Photo-Elastic Modulator Interferograms].

    Science.gov (United States)

    Zhang, Min-juan; Wang, Zhi-bin; Li, Xiao; Li, Jin-hua; Wang, Yan-chao

    2015-05-01

    In order to improve the accuracy and stability of the rebuilt spectrums, it is necessary that stability analysis and nicety measuring of the maximum optical path difference of interferograms in the photo-elastic modulator Fourier transform spectrometers(PEM-FTS). The maximum optical difference of interferograms is uncertain parameter, and it is relate to the resonant state, characteristic of frequency-thermal drift and driving voltage of PEM. Therefore, based on the principle of photo-elastic modulator Fourier transform interferometer, the model of the freguency-thermal drift is built, and the variety of the maximum optical path difference is analyzed; A measuring method of the maximum optical path difference is put forward, which is zero-crossing counting of laser's interference signal when the driving signal of PEM is as the standard. In the method the dual channel high-speed comparator and FPGA are used to transform sine wave to square wave, to realize zero-crossing trigger counting and errors compensation. On the condition that the 670. 8 nm laser is as the power source to produce the reference interferograms by the PEM interferometer, the 77. 471 µm maximum optical path difference could be measured by the zero-crossing counting the measuring errors is less than 0. 167 nm, the rebuilt spectral peak wavelength errors of the infrared blackbody is less than 2 nm. the result is content with PEM-FTS.

  19. Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions.

    Science.gov (United States)

    Herbst, Daniel P

    2017-03-01

    Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30-70% glycerol-saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another.

  20. Water-flushing toilets: Systemic development and path-dependent characteristics and their bearing on technological alternatives

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt

    2007-01-01

    In this study, I analyse the historical process that led to embedding water-flushing toilets in the Western world, then I explore innovative developments connected to alternative toilet solutions that use less water. The core argument is that path-dependent characteristics are found both...... at the systemic level and the level of daily practices. Systemic development and its embedding into daily practices changed and contributed to a lock-in. Then current attempts to introduce alternative toilet solutions are analysed. I conclude by suggesting that established water-flushing routines impede...

  1. Water-flushing toilets: Systemic development and path-dependent characteristics and their bearing on technological alternatives

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt

    2007-01-01

    In this study, I analyse the historical process that led to embedding water-flushing toilets in the Western world, then I explore innovative developments connected to alternative toilet solutions that use less water. The core argument is that path-dependent characteristics are found both...... at the systemic level and the level of daily practices. Systemic development and its embedding into daily practices changed and contributed to a lock-in. Then current attempts to introduce alternative toilet solutions are analysed. I conclude by suggesting that established water-flushing routines impede...

  2. The use of digital technology in finding multiple paths to solve and extend an equilateral triangle task

    Science.gov (United States)

    Santos-Trigo, Manuel; Reyes-Rodriguez, Aaron

    2016-01-01

    Mathematical tasks are crucial elements for teachers to orient, foster and assess students' processes to comprehend and develop mathematical knowledge. During the process of working and solving a task, searching for or discussing multiple solution paths becomes a powerful strategy for students to engage in mathematical thinking. A simple task that involves the construction of an equilateral triangle is used to present and discuss multiple solution approaches that rely on a variety of concepts and ways of reasoning. To this end, the use of a Dynamic Geometry System (GeoGebra) became instrumental in constructing and exploring dynamic models of the task. These model explorations provided a means to generate novel mathematical results.

  3. Culminating paths

    Directory of Open Access Journals (Sweden)

    Mireille Bousquet-Mélou

    2008-04-01

    Full Text Available Let a and b be two positive integers. A culminating path is a path of ℤ 2 that starts from (0,0, consists of steps (1,a and (1,-b, stays above the x-axis and ends at the highest ordinate it ever reaches. These paths were first encountered in bioinformatics, in the analysis of similarity search algorithms. They are also related to certain models of Lorentzian gravity in theoretical physics. We first show that the language on a two letter alphabet that naturally encodes culminating paths is not context-free. Then, we focus on the enumeration of culminating paths. A step by step approach, combined with the kernel method, provides a closed form expression for the generating function of culminating paths ending at a (generic height k. In the case a = b, we derive from this expression the asymptotic behaviour of the number of culminating paths of length n. When a > b, we obtain the asymptotic behaviour by a simpler argument. When a < b, we only determine the exponential growth of the number of culminating paths. Finally, we study the uniform random generation of culminating paths via various methods. The rejection approach, coupled with a symmetry argument, gives an algorithm that is linear when a ≥ b, with no precomputation stage nor non-linear storage required. The choice of the best algorithm is not as clear when a < b. An elementary recursive approach yields a linear algorithm after a precomputation stage involving O (n 3 arithmetic operations, but we also present some alternatives that may be more efficient in practice.

  4. Path Sensitization

    Institute of Scientific and Technical Information of China (English)

    赵著行; 闵应骅; 等

    1997-01-01

    For different delay models,the concept of sensitization can be very different.Traditonal concepts of sensitization cannot precisely describe circuit behavior when the input vectors change very fast.Using Boolean process aporoach,this paper presents a new definition of sensitization for arbitrary input waveforms.By this new concept it is found that if the inputs of a combinational circuit can change at any time,and each gate's delay varies within an interval (bounded gate delay model),then every path,which is not necessarily a single topological path,is sensitizable.From the experimental results it can be seen that,all nonsensitizable paths for traditional concepts actually can propagate transitions along them for some input waveforms.However,specified time between input transitions(STBIT) and minimum permissible pulse width(ε)are two major factors to make some paths non-sensitizable.

  5. 77 FR 27501 - In the Matter of One Voice Technologies, Inc., Orchestra Therapeutics, Inc., Path 1 Network...

    Science.gov (United States)

    2012-05-10

    ... Technologies, Inc., Pavilion Energy Resources, Inc. (f/k/a Global Business Services, Inc.), Pine Valley Mining... securities of Pavilion Energy Resources, Inc. (f/k/a Global Business Services, Inc.) because it has not...

  6. Interactive physics apparatus: influence on interest of secondary school students in pursuing a career path in science, technology, engineering and mathematics (STEM)

    Science.gov (United States)

    Lubrica, Joel V.; Abiasen, Jovalson T.; Dolipas, Bretel B.; Ramos, Jennifer Lyn S.

    2017-01-01

    In this article, we present results of our endeavours as physics educators to facilitate and support pedagogical change and development in the educational system of a developing country, the Philippines. We have discovered that the interaction of junior high school (years 7-10) students with physics apparatus can influence students’ interest in pursuing a career in science, technology, engineering and mathematics (STEM). This assertion stems from self-reports of students who gave their views immediately after their exposure to interactive apparatus in their own school, outside of their usual lessons. Participants claimed that their interest in following a STEM career path was ‘greatly increased’ due to their exposure to these apparatus. This was true even for students who were intending to take a non-STEM career path. Thus, we recommend that, in settings that have constraints involving access to practical equipment, ways to introduce school level interactive physics apparatus to secondary school students be conducted in order to attract more students towards STEM courses. Possibly, policies encouraging this type of exposure should also be formulated.

  7. THE USE OF GIS TECHNOLOGY TO IDENTIFY THE SHORTEST TRAVEL PATHS. CASE STUDY: THE CITY OF CRAIOVA

    Directory of Open Access Journals (Sweden)

    DANIEL SIMULESCU

    2012-04-01

    Full Text Available In a city with a population of 298.928 inhabitants (January 2009, about 278.7 km of road (without the northern ring road and a road density of 3.1 km/km2, identifying the optimal routes for moving vehicles is a necessary operation under the temporary removal of use (28 months, from March 2011 of some street sectors in the downtown area, which is currently the subject of an infrastructure modernization work, in order to streamline the cars traffic.The optimal routes were identified using Network Analyst extension of ArcGIS Desktop 9.2 software, which calculated the shortest paths between a point of departure and an arrival one, using distance as impedance. In this case the points between which it was intended to identify the shortest routes were selected taking into account the fact that much of the Craiova’s population located in the north – western neighborhoods, faces traffic problems while they are moving toward the center of city. Therefore, this material is intended to be a support, resulted in some maps, in order to identity and choose the best travel route.

  8. The Cognition and Neuroergonomics (CaN) Collaborative Technology Alliance (CTA): Scientific Vision, Approach, and Translational Paths

    Science.gov (United States)

    2012-09-01

    systems incorporating dry sensor technology and small, lightweight, wearable data acquisition circuits now feasible and available for current...observe and record a variety of levels ( physiological , physical, and environmental) of neurobehavioral data regarding operator and environmental state...system could function based, in part, on the neurocognitive data that it received from monitors of Soldier physiology and behavior. This

  9. Results of an Australian trial using SurePath liquid-based cervical cytology with FocalPoint computer-assisted screening technology.

    Science.gov (United States)

    Bowditch, Ron C; Clarke, Joanne M; Baird, Phillip J; Greenberg, Merle L

    2012-12-01

    BD FocalPoint GS™ computer-assisted screening of BD SurePath® liquid-based cervical cytology slides (SP + FP) was compared with screening an accompanying conventional cervical Papanicolaou (Pap) smear (CON) in a split sample trial of 2,198 routine specimens. The rate of unsatisfactory specimens in the SP + FP arm was 0.2% compared with 4.1% in the conventional Pap smear, a significant reduction. There was no statistically significant difference between SP + FP and CON for the detection of histologically confirmed high-grade (HG) lesions in the routine split sample specimens (n = 9). To further test the sensitivity of SP + FP for HG lesions, 38 SurePath slides from confirmed HG cases, without an accompanying CON, were interpolated among the routine smears. In every one of the 47 confirmed HG cases, either HG cells were present in the microscope fields selected by FocalPointGS™ for review by the screening cytologist (46 of 47), or full screening of the slide was indicated by the FocalPointGS™ (1 of 47), confirming the effectiveness of SP + FP technology for primary screening. In a small number of cases, the screening cytologist did not recognize the abnormality even though on review HG cells were present in fields selected by FocalPointGS™. The overall detection rate was 93% for HG squamous lesions; 89% for known HG endocervical glandular lesions; and 91% for known endometrial carcinoma. In conclusion, the SP + FP detected 100% of HG abnormalities in the trial set; significantly reduced the rate of unsatisfactory specimens; and improved the overall screening rate of detection of HG abnormalities particularly of glandular lesions when compared with other screening technologies.

  10. Path Dependence

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    Begrebet Path Dependence blev oprindelig udviklet inden for New Institutionel Economics af bl.a. David, Arthur og North. Begrebet har spredt sig vidt i samfundsvidenskaberne og undergået en udvikling. Dette paper propagerer for at der er sket så en så omfattende udvikling af begrebet, at man nu kan...... tale om 1. og 2. generation af Path Dependence begrebet. Den nyeste udvikling af begrebet har relevans for metodologi-diskusionerne i relation til Keynes...

  11. Path Creation, Path Dependence and Breaking Away from the Path

    DEFF Research Database (Denmark)

    Wang, Jens Erik; Hedman, Jonas; Tuunainen, Virpi Kristiina

    2016-01-01

    The explanation of how and why firms succeed or fail is a recurrent research challenge. This is particularly important in the context of technological innovations. We focus on the role of historical events and decisions in explaining such success and failure. Using a case study of Nokia, we develop...... the importance of intermediate outcomes, which in the case of Nokia was the importance of software ecosystems and adaptable mobile devices. Furthermore, we show how the layers of path dependence mutually reinforce each other and become stronger....

  12. Paths through interpretive territory: Two teachers' enactment of a technology-rich, inquiry-fostering science curriculum

    Science.gov (United States)

    McDonald, Scott Powell

    New understandings about how people learn and constructivist pedagogy pose challenges for teachers. Science teachers face an additional challenge of developing inquiry-based pedagogy to foster complex reasoning skills. Theory provides only fuzzy guidance as to how constructivist or inquiry pedagogy can be accomplished in a wide variety of contexts and local constraints. This study contributes to the understanding of the development of constructivist, inquiry-based pedagogy by addressing the question: How do teachers interpret and enact a technology-rich, inquiry fostering science curricula for fifth grade students' biodiversity learning? This research is a case study of two teachers chosen as critical contrasting cases and represent differences across multiple criteria including: urban I suburban, teaching philosophy, and content preparation. The two fifth grade teachers each enacted BioKIDS: Kids' Inquiry in Diverse Species, an eight week curriculum focused on biodiversity. BioKIDS incorporates multiple learning technologies to support student learning including handheld computer software designed to help students collect field data, and a web-based resource for data on local animal species. The results of this study indicate there are tensions teachers must struggle with when setting goals during enactment of inquiry science curricula. They must find a balance between an emphasis on authentic learning and authentic science, and between natural history and natural science. Authentic learning focuses on students' interests and lives; Authentic science focuses on students working with the tools and processes of science. Natural history focuses on the foundational skills in science of observation and classification. Natural science focuses on analytical science drawing on data to develop claims about the world. These two key tensions in teachers' goal setting were critical in defining and understanding differences in how teachers interpreted a curriculum to meet

  13. 基于信息技术的物流创新路径研究%Research on Logistics Innovation Path Based on Information Technology

    Institute of Scientific and Technical Information of China (English)

    陈海

    2015-01-01

    The development of the logistics industry needs innovation,and logistics innovation includes logistics activity innovation,logistics function innovation,logistics management innovation and logistics planning innovation.Information technology is an important factor of logistics innovation,which's application expands the logistics market demand,and also affects the logistics management and operation.Through the research of logistics innovation path based on information technology,it is useful to realize the integration of information technology and logistics innovation.Improving the construction of logistics information standard, accelerating logistics information personnel training,increasing logistics information technology research and development and playing a role of logistics information network are basic strategy.%物流业的发展需要创新,物流创新表现在物流活动创新、物流功能创新、物流管理创新与物流规划创新。信息技术是物流创新的重要因素,信息技术的应用扩大了物流市场需求,也影响到物流管理与运作。通过研究基于信息技术的物流创新路径,有助于实现信息技术与物流创新的融合。完善物流信息标准建设、加快物流信息人才培养、加大物流信息技术研发和发挥物流信息网络作用是基于信息技术的物流创新的基本策略。

  14. 企业绩效考核的技术路径%Technology path of Enterprise Performance Appraisal

    Institute of Scientific and Technical Information of China (English)

    李青; 陈龙

    2013-01-01

      The article summarizes the relevant research results of the performance evaluation technology about home and abroad. It introduces some performance appraisal techniques. According to the characteristics of individual performance appraisal technology, it develops an enterprise performance appraisal road map. Performance appraisal road map is divided into six steps and mutual steps appear condition of cycle and cycle. We should pay attention to two issues in the process of the implementation of the performance appraisal road map:changes in the environment and the asymmetry of information. Finally, we point out that the road map has great significance for human resource management.%  文章总结了国内外绩效考核技术的相关研究成果,介绍了一些绩效考核技术。根据各个绩效考核技术的特点,制定了企业绩效考核路径图。绩效考核路径图分为六个步骤,步骤之间循环往复地进行。在实施绩效考核路径图的过程中要注意两个问题:环境的变化和信息的不对称。最后指出路径图对企业人力资源管理具有重要意义。

  15. Experiences in Applying Earth Observing Satellite Technology in SERVIR Regions with an Emphasis on Disasters: Successes, Lessons and Paths Forward

    Science.gov (United States)

    Anderson, Eric

    2017-01-01

    Earth observing satellites offer a unique perspective of our environment from the vantage point of space. Repeated measurements of the Earths subsystems such as the biosphere, atmosphere, lithosphere, hydrosphere, and of humans interactions with their environments, allow for a better understanding of Earth system processes, and they can provide input for decision making in areas of environmental management and disaster risk reduction. SERVIR is a joint initiative of the US National Aeronautics and Space Administration (NASA) and the US Agency for International Development (USAID) that began in 2005 and has been active in applying Earth observations for sustainable development in many regions around the world, recently the Lower Mekong and West Africa regions. This talk will highlight some successes achieved and lessons learned through SERVIR in Central America, Eastern Southern Africa, and the Hindu Kush-Himalaya region, focusing on disasters. We will also present opportunities for enhanced decision making with Earth observations and geospatial technologies in the Lower Mekong region.

  16. Path Creation

    DEFF Research Database (Denmark)

    Karnøe, Peter; Garud, Raghu

    2012-01-01

    This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts. Competenc......This paper employs path creation as a lens to follow the emergence of the Danish wind turbine cluster. Supplier competencies, regulations, user preferences and a market for wind power did not pre-exist; all had to emerge in a tranformative manner involving multiple actors and artefacts....... Competencies emerged through processes and mechanisms such as co-creation that implicated multiple learning processes. The process was not an orderly linear one as emergent contingencies influenced the learning processes. An implication is that public policy to catalyse clusters cannot be based...

  17. Tecnologias na Educação: dos caminhos trilhados aos atuais desafios Technology in Education: the paths travelled to the current challenges

    Directory of Open Access Journals (Sweden)

    Maria Elizabeth Bianconcini de Almeida

    2008-09-01

    Full Text Available Este artigo apresenta um resgate da recente história das tecnologias de informação e comunicação na educa��ão a partir de uma retrospectiva dos caminhos trilhados em países cujas ações tiveram forte influência na trajetória brasileira, com destaque especial para Estados Unidos da América, França e Portugal. Em seguida, o tema é tratado no âmbito da realidade brasileira até o momento atual caracterizado pela proposta de inserir equipamentos móveis de pequeno porte e baixo custo (laptop educacional nas escolas. No final, destaca as principais convergências que se sobressaem na história das tecnologias na educação desses países e conclui que, apesar da disparidade quantitativa em relação à disponibilidade de recursos entre esses países, a concretização das ações se mostra aquém dos objetivos, metas, desejos e utopias, com desafios a superar, em especial no que se refere à formação de educadores, para a efetiva integração das TIC na escola e no currículo. Palavras-chave: Tecnologias de Informação e Comunicação. Tecnologias na Educação. Políticas Públicas. Integração de Tecnologias ao Currículo.This article presents a review of the recent history of information and communication technologies in education through a retrospective of the paths traveled in countries whose actions have had strong influence on the Brazilian trajectory, with special emphasis on the United States, France and Portugal. The subject is next addressed in the context of the Brazilian reality, characterized by the current proposal to introduce small, portable, low cost equipment (educational laptops in schools. Finally, the major convergences that stand out in the history of technology in education in these countries is highlighted. It is concluded that, despite the quantitative disparity between these countries with respect to the availability of resources, the implementation of actions has not achieved the objectives, goals

  18. 科技型中小企业适应性成长路径研究%Towards an adaptive growth path of medium and small technological enterprises

    Institute of Scientific and Technical Information of China (English)

    黄春萍; 刘奎颖; 曾珍香

    2011-01-01

    Medium and small technological enterprises are the main force of national economic development. Their healthy growth is the common concern of both the business and academic circles. The adaptation of these enterprises and their adaptive growth stages are analyzed and a model for their adaptive growth path is established. Finally, cluster analysis is applied in an empirical study.%科技型中小企业是国民经济发展的主力军,其健康成长是企业界和学术界共同关心的热点问题.本文首先分析了科技型中小企业的适应性及其适应性成长阶段,分别是创业阶段、发展阶段、成熟阶段和蜕变阶段;进而基于企业适应性这一视角,提出了科技型中小企业适应性成长路径为自主发展型、动态模仿型和创新涌现型,并构建了其适应性成长路径模型,最后应用聚类分析进行了实证研究.

  19. 基于专利引文网络的技术轨道识别研究——以太阳能光伏电池板领域为例%Research on identification of technological evolution path based on patent citation network —— taking solar photovoltaic panels technology as an example

    Institute of Scientific and Technical Information of China (English)

    杨中楷; 刘佳

    2011-01-01

    Using patents and patent citation network to identify technological evolution path. Elaborate the principle of technological evolution path identification, form the algorithm of technological evolution path identification and provide the feasibility of technological evolution path identification as well as its visualization. Identify and map the technological evolution path combining the solar photovoltaic panel data, elaborate main nodes and explore technology evolution history as well as future trends to provide some decision -making reference strategy on the development of related industries in China.%利用专利及其引文网络进行技术轨道识别研究。阐述技术轨道识别的原理,形成技术轨道识别的算法,从理论上提供技术轨道识别及其可视化的可行性。结合太阳能光伏电池板数据,识别并绘制出技术轨道图谱,对主要节点进行重点阐述,探寻技术沿革的历史脉络和未来趋势,对我国相关领域的发展战略提供决策参考。

  20. innovation path exploration

    Directory of Open Access Journals (Sweden)

    Li Jian

    2016-01-01

    Full Text Available The world has entered the information age, all kinds of information technologies such as cloud technology, big data technology are in rapid development, and the “Internet plus” appeared. The main purpose of “Internet plus” is to provide an opportunity for the further development of the enterprise, the enterprise technology, business and other aspects of factors combine. For enterprises, grasp the “Internet plus” the impact of the market economy will undoubtedly pave the way for the future development of enterprises. This paper will be on the innovation path of the enterprise management “Internet plus” era tied you study, hope to be able to put forward some opinions and suggestions.

  1. Agricultural-industrial technological paths

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Paulo Sergio Graziano; Nogueira, Luiz Augusto Horta; Cantarella, Heitor; Rossetto, Raffaella; Franco, Henrique C. Junqueira; Braunbeck, Oscar

    2012-07-01

    The chapter approaches the identification of relevant parameters, sugarcane planting, soil preparation and compaction, mechanical harvesting, straw recovery, use of residues, soil carbon sequestration, greenhouse gases emission,l other effects, production of coal as an alternative for C storage, use of biofuels (bioethanol and biodiesel) in agriculture and transport of sugarcane, estimation of diesel consumption in the sugarcane industry, scenarios considered for the use of biofuels, modelling the impacts of the adoption of biofuels - fuel consumption and emissions, energy and impact of biofuels use in bioethanol production, impact of adoption of biofuels on emissions in bioethanol production, and increase in the scale (milling capacity) of the sugar and bioethanol mills.

  2. 战略性新兴产业突破性技术创新路径研究%Research on the Radical Technology Innovation Paths of Strategic Emerging Industry

    Institute of Scientific and Technical Information of China (English)

    王宏起; 田莉; 武建龙

    2014-01-01

    战略性新兴产业是典型的创新驱动型产业,重大技术突破是战略性新兴产业持续发展的关键。为此,本文运用模块化理论思想,在对战略性新兴产业突破性技术创新内涵与模块化特征进行分析基础上,构建战略性新兴产业突破性技术创新路径:“外围模块→核心模块”路径、“核心模块→架构规则”路径和“架构规则→核心模块”路径,并以我国高端装备制造业的典型代表---大飞机产业的突破性技术创新为例论证路径的科学性和可行性,为我国战略性新兴产业开展突破性技术创新提供了理论支持和决策参考。%Strategic emerging industry is a typical innovation -driven industry , and major technological breakthrough is the key to sustainable development of strategic emerging industry . Thus , from the angle of modular theory , the paper builds radical technology inno-vation paths of strategic emerging industry :“peripheral modules→core modules” path ,“core modules→architecture rules” path and “ar-chitecture rules→core modules” path , based on analyzing the connotation and modular characteristics of radical technology innovation of strategic emerging industry , and then validates the paths of being scientific and feasible with the example of typical representative of high -end equipment manufacturing industry---radical technology innovation paths of large aircraft industry , so as to provide theoretical and method support as well as decision references for strategic emerging industry to carry out the radical technology innovation .

  3. Jan Åge Riseth; Sámi reindeer management under technological change 1960-1990: Implications for Common-Pool Resource Use Under Various Natural and Instututional Conditions. A comparative analysis of regional development paths....

    Directory of Open Access Journals (Sweden)

    Rolf Egil Haugerud (ed.

    2000-03-01

    Full Text Available On June 22, Cand. Agric. Jan Åge Riseth successfully defended his dissertation "Sami reindeer management under technological change 1960-1990: Implications for Common-Pool Resource Use Under Various Natural And Institutional Conditions. A comparative analysis of regional development paths in West Finnmark, North Trøndelag, and South Trøndelag/Hedmark, Norway." for the degree Dr. Scient, at the Agricultural University of Norway (AUN, Dept. of Economics and Social Sciences.

  4. Jan Åge Riseth; Sámi reindeer management under technological change 1960-1990: Implications for Common-Pool Resource Use Under Various Natural and Instututional Conditions. A comparative analysis of regional development paths....

    OpenAIRE

    Rolf Egil Haugerud (ed. in chief)

    2000-01-01

    On June 22, Cand. Agric. Jan Åge Riseth successfully defended his dissertation "Sami reindeer management under technological change 1960-1990: Implications for Common-Pool Resource Use Under Various Natural And Institutional Conditions. A comparative analysis of regional development paths in West Finnmark, North Trøndelag, and South Trøndelag/Hedmark, Norway." for the degree Dr. Scient, at the Agricultural University of Norway (AUN), Dept. of Economics and Social Sciences.

  5. 创新导图在技术创新路径选择中的应用研究%Application Research of Innovation Mapping in the Selection of Technology Innovation Paths

    Institute of Scientific and Technical Information of China (English)

    李兵; 朱东华; 杨帆

    2015-01-01

    With the trend of increasing global competition, companies have to carry out technical innovation in or-der to gain dominance in the market. How to identify opportunities for technological innovation and to select the path of technological innovation have become the company's current urgent problem. In this paper, I put forward a model about the path selection of technical innovation based on innovation mapping, and then draw two innova-tion mappings about solar photovoltaic technology using Derwent patent data to explore the path selection process of technical innovation. This method is a combination of qualitative and quantitative analysis methods to improve the objectivity and accuracy of path selection. What's more, it can support data support for experts making deci-sion about research and development and enterprises carrying out technical innovation.%随着全球化竞争趋势的日益加剧,企业需要不断地进行技术创新才能在市场上获得优势地位,如何识别技术创新机会、并选择有效的技术创新路径成为企业当前亟待解决的难题。在评述国内外主要技术创新方法的基础上,构建了基于创新导图的技术创新路径选择模型,并以德温特专利数据为基础,构建了太阳能光伏发电技术领域的创新导图,探讨了该领域技术创新路径的选择过程。

  6. 分层实体制造技术中激光切割路径的优化%Optimization of Laser Cutting Paths in Laminated Object Manufacturing Technology

    Institute of Scientific and Technical Information of China (English)

    刘斌; 阮锋; 黄树槐

    2001-01-01

    The laser cutting paths and cutting speed usually influence the cutting time of each layer in the laminated object manufacturing technology. If the cutting speed is not changed, the optimization of laser cutting paths will directly influence the cutting time of each layer. So, the method of optimization of laser cutting paths is discussed in detail in this paper. It will reduce some needless moving paths and shorten the displacement in order to improve the efficient of manufacturing.%在分层实体制造中,激光切割路径和切割速度影响每层的切割加工时间.在切割速度一定的情况下,激光切割路径的优化与否将直接影响每层的切割加工时间.本文对激光切割路径进行优化的方法,可以减少一些不必要的移动路径和缩短空行程位移,从而达到提高加工效率的目的

  7. Research on the Path Finding Technology in the Virtual Scene%虚拟场景中路径搜索技术的研究

    Institute of Scientific and Technical Information of China (English)

    柯健; 李帅; 郝沅君; 张倩倩

    2012-01-01

    The path finding system is a part of the artificial intelligence which is often used in games or virtual reality. A few path finding algorithms often used in path finding system are discussed, heuristic path finding algorithm such as A^* and IDA^* are improved, which obtains balanced result in storage space and running time. A few methods which dividing searching space are discussed, and path finding is implemented based on navigation mesh.%路径搜索系统一般是游戏或虚拟现实中常用的人工智能的一部分.分析讨论路径搜索系统中几种常用的路径搜索算法,对启发式路径搜索方法A^*算法和IDA^*算法进行了改进,在存储空间和运行时间上取得了较为平衡的效果.讨论搜索空间的几种划分方法,在导航网格的基础上实现了路径的搜索.

  8. The Shortest Path with Intelligent Algorithm

    Directory of Open Access Journals (Sweden)

    Surachai Panich

    2010-01-01

    Full Text Available Problem statement: Path planning algorithms need to be developed and implemented in a suitable manner to give better understanding about the intelligent system and also stimulates technological supply to enormous demands in an intelligent vehicle industry. Approach: This study concerned with intelligent path planning using A* search algorithm. Results: This study introduced intelligent path planning with A* search algorithm, which use to generate the most efficient path to goal. The algorithm was tested on simulator. Conclusion: This study is an implementation of a path planning for an intelligent path planning. The implementations are tested and verified with the simulation software. The path planning algorithms were selected for the implementation and to verify them.

  9. 基于核心-辅助技术匹配的二次创新及其演化路径研究%Secondary Innovation and Evolution Path based on the Fitness between Core and Complementary Technologies

    Institute of Scientific and Technical Information of China (English)

    吴晓波; 窦伟; 高钰; 黄芳俪

    2011-01-01

    本研究提出了基于核心技术与辅助技术匹配的二次创新及其演化模型,详细归纳了后发企业创新演化路径,以解释中国本土企业的创新成功.通过对中兴通讯案例的编码和归类,本文界定了后发企业核心技术与辅助技术的学习与相关创新.通过对纵向分析,后发企业的创新可以分为三个阶段:在狭义二次创新阶段,后发企业进行核心技术引进模仿和本地辅助技术的利用型创新,为核心技术适配本地的辅助技术;在后二次创新阶段,后发企业进行辅助技术探索和核心技术利用,跟踪国外新兴核心技术,进行基于辅助技术研发的价值创造型创新;在一次创新阶段,后发企业进行核心技术探索,并进行辅助技术利用以推动核心技术创新.本文归纳了两个理论命题:第一,发展中国家后发企业的创新是一个核心技术从模仿引进、利用创新到探索创新的演化过程,辅助技术常常先于核心技术进入探索阶段;第二,后发企业核心技术的利用创新驱动了辅助技术探索,核心技术探索创新驱动了辅助技术利用.%In the past 20 years, an increasing number of Chinese firms have followed the innovation path of having little core technology breakthroughs, followed by core technology development. The innovation path enables many local leading firms to rival against foreign companies. However, the innovation path as a technological learning process often ignores the importance of complemetnary technology. The existing literature lacks studies on how latecomers can innovate from complementary technologies and evolve into core technology exploration. Secondary innovation refers to those latercomes who import foreign core technologies and then innovate them in emerging markets. The purpose of this paper is to explain the success of innovation within Chinese enterprises by focusing on the secondary innovation based on the fitness between core and

  10. Entanglement by Path Identity

    CERN Document Server

    Krenn, Mario; Lahiri, Mayukh; Zeilinger, Anton

    2016-01-01

    Quantum entanglement is one of the most prominent features of quantum mechanics and forms the basis of quantum information technologies. Here we present a novel method for the creation of quantum entanglement in multipartite and high-dimensional photonic systems, exploiting an idea introduced by the group of Leonard Mandel 25 years ago. The two ingredients are 1) superposition of photon pairs with different origins and 2) aligning photon paths such that they emerge from the same output mode. We explain examples for the creation of various classes of multiphoton entanglement encoded in polarization as well as in high-dimensional Hilbert spaces -- starting only from separable (non-entangled) photon pairs. For two photons, we show how arbitrary high-dimensional entanglement can be created. Interestingly, a common source for two-photon polarization entanglement is found as a special case. We discovered the technique by analyzing the output of a computer algorithm designing quantum experiments, and generalized it ...

  11. The Application of Steam Turbine Steam Path Audit Technology%汽轮机通流状态经济性评估技术的现场应用

    Institute of Scientific and Technical Information of China (English)

    杨海生; 吴瑞涛; 李忠杰

    2012-01-01

    Analysis was made on the factors influencing the turbine steam path efficiency, and the concept of the turbine steam path audit was introduced. Using the turbine steam path technology, quantitative analysis and calculation for the factors influencing the steam turbine efficiency can be made using relevant tool software,which can help the decision making of the key maintenance area during the turbine overhaul. An example was given for one super-critical steam turbine, including the measurement data got during the turbine overhaul and the audit results,and the key maintenance tasks set out based on the steam path audit.%对影响汽轮机通流效率的各项因素的作用机理进行了定性分析,并对汽轮机通流状态经济性评估的基本概念进行了阐述.进行汽轮机通流部分经济性状态评估后,可以利用相关的分析工具软件对影响汽轮机通流部分经济性的因素进行有效分析及计算,为电厂大修中汽轮机的检修提供检修的重点.以某一超临界660MW汽轮机为例,给出了汽轮机通流状态经济性评估的大修通流状态实测数据及评估结果,在此基础上确定了汽轮机大修的重点检修工作.

  12. Spraying painting robots path planning based on point cloud data processing technology%基于点云处理技术的喷涂机器人喷枪轨迹生成研究

    Institute of Scientific and Technical Information of China (English)

    孙国朋; 戴立玲; 卢章平; 李明珠

    2011-01-01

    That point cloud data is used a the data formats ofsprayingpainting robot path planning is put forward.The point cloud data processing technology is used to generate spraying robot path,which includes point cloud preprocessing、region segmentation、point cloud slicing、acquiring the normal vectors of the sampled points、the sampled points offsetting and so on. The point cloud data processing technology is used to spraying robot trajectory planning,point cloud segmentation make its features clear and reduce the complexity of spraying process,it can control the position of spraying gun well and also improve quality and efficiency of spraying%提出了以点云数据作为喷涂机器人轨迹生成的数据格式,采用点云处理技术,通过对点云的预处理、区域分割,点云切片、采样点求取法矢量及沿法矢量方向偏移等方法实现了喷涂机器人轨迹的生成.将点云技术运用到喷涂机器人轨迹规划,通过点云区域分割细化了点云特征,降低了喷涂工艺的复杂性,同时很好的控制喷枪的位置,提高了喷涂的质量和效率.

  13. A Path Analysis of Pre-Service Teachers' Attitudes to Computer Use: Applying and Extending the Technology Acceptance Model in an Educational Context

    Science.gov (United States)

    Teo, Timothy

    2010-01-01

    The purpose of this study is to examine pre-service teachers' attitudes to computers. This study extends the technology acceptance model (TAM) framework by adding subjective norm, facilitating conditions, and technological complexity as external variables. Results show that the TAM and subjective norm, facilitating conditions, and technological…

  14. Review on the Path Selection of China' s Technological Progress%我国技术进步路径及方式选择的研究述评

    Institute of Scientific and Technical Information of China (English)

    余泳泽

    2012-01-01

    The path selection of China' s technological progress is controversial. In theory, there is a controversy of " endowment hypothesis" in the theory of comparative advantage and "technology development hypothesis" in the theory of competitive advantage. In practice,how to choose imitative innovation and independent innovation is a controversy. Considering the situation of the inequality of regional innovation factor endowment and the coexistence of both traditional industries and emerging industries, the technology progress path of various regions and various types of industrial will not take consistent strategy. Future research should consider combining the dynamics of technological progress and its path. Comparative advantage and competitive advantage should not only stay in a static comparative paradigm.%我国技术进步路径及方式选择问题一直存在着较大争议。在理论上,存在着基于比较优势理论的“要素禀赋说”与竞争优势理论的“技术赶超说”的争议;在实践上,存在着模仿性创新与自主创新如何选择的争议。考虑到我国要素禀赋非均衡分布以及传统产业与新兴产业并存的现状,各地区与各种类型产业技术进步路径及方式不可能采取“一刀切”的战略。未来研究应当充分将技术演进的动态性和技术进步路径及方式演进的动态性相结合,比较优势和竞争优势不应只停留在静态比较的范式下。

  15. Innovative development path of ethnomedicines: the interpretation of the path.

    Science.gov (United States)

    Zhu, Zhaoyun; Fu, Dehuan; Gui, Yali; Cui, Tao; Wang, Jingkun; Wang, Ting; Yang, Zhizhong; Niu, Yanfei; She, Zhennan; Wang, Li

    2017-03-01

    One of the primary purposes of the innovative development of ethnomedicines is to use their excellent safety and significant efficacy to serve a broader population. To achieve this purpose, modern scientific and technological means should be referenced, and relevant national laws and regulations as well as technical guides should be strictly followed to develop standards and to perform systemic research in producing ethnomedicines. Finally, ethnomedicines, which are applied to a limited extent in ethnic areas, can be transformed into safe, effective, and quality-controllable medical products to relieve the pain of more patients. The innovative development path of ethnomedicines includes the following three primary stages: resource study, standardized development research, and industrialization of the achievements and efforts for internationalization. The implementation of this path is always guaranteed by the research and development platform and the talent team. This article is based on the accumulation of long-term practice and is combined with the relevant disciplines, laws and regulations, and technical guidance from the research and development of ethnomedicines. The intention is to perform an in-depth analysis and explanation of the major research thinking, methods, contents, and technical paths involved in all stages of the innovative development path of ethnomedicines to provide useful references for the development of proper ethnomedicine use.

  16. Innovation paths in wind power

    DEFF Research Database (Denmark)

    Lema, Rasmus; Nordensvärd, Johan; Urban, Frauke

    Denmark and Germany both make substantial investments in low carbon innovation, not least in the wind power sector. These investments in wind energy are driven by the twin objectives of reducing carbon emissions and building up international competitive advantage. Support for wind power dates back...... between Denmark and Germany when it comes to innovation pathways, both in technological and organisational innovation. In turbine technology, the similarities are the constant increase in turbine size and quality. The key difference to be found is the relative importance of different turbine designs....... The ‘Danish Design’ remains the global standard. The direct drive design, while uncommon in Denmark, dominates the German installation base. Direct drive technology has thus emerged as a distinctly German design and sub-trajectory within the overall technological innovation path. When it comes to organising...

  17. The development of radiation hardened tele-robot system - Development of path-planning and control technology for tele-operated redundant manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Pyung Hun; Park, Ki Cheol; Park, Suk Ho [Korea Advanced Institute of Science and Technology, Taejon (Korea)

    1999-04-01

    This project focuses on the development of the control system for a teleoperated redundant manipulator, which performs many tasks dexterously, while avoiding obstacles, instead of human workers in the extreme situations like nuclear power plants. To this end, four consecutive research works have been performed. First, two new methods for global path-planning have been developed to inspect the global behavior of the redundant manipulator. Second, characteristics of optimal solutions(COS) under inequality constraints have been analyzed and, using the COS, how to greatly enhance the conventional redundancy resolution methods in terms of performance and repeatability has also been proposed. Third, an effective control method for a redundant manipulator has been developed, which incorporates all kinds of physical limits into practical inequality constraints and is computationally efficient for real-time purposes. Finally, using this control method as the controller of the slave redundant manipulator and developing a master manipulator, the inertial torque and gravitation torque of which are negligible, a force-reflected teleoperation control system has been developed. Through the teleoperation control system, human operator can accurately control the position and the force of the end-effector of the slave manipulator while feeling the interaction force between the slave and the workpiece. In addition, the slave redundant manipulator autonomously can control the impedance and can optimize a given performance measure while avoiding physical limits such as joint angle limits and obstacles. 49 refs., 43 figs., 10 tabs. (Author)

  18. The Path of New Information Technology Affecting Educational Equality in the New Digital Divide--Based on Information System Success Model

    Science.gov (United States)

    Zheng, Qian; Liang, Chang-Yong

    2017-01-01

    New information technology (new IT) plays an increasingly important role in the field of education, which greatly enriches the teaching means and promotes the sharing of education resources. However, because of the New Digital Divide existing, the impact of new IT on educational equality has yet to be discussed. Based on Information System Success…

  19. Path Integrals and Hamiltonians

    Science.gov (United States)

    Baaquie, Belal E.

    2014-03-01

    1. Synopsis; Part I. Fundamental Principles: 2. The mathematical structure of quantum mechanics; 3. Operators; 4. The Feynman path integral; 5. Hamiltonian mechanics; 6. Path integral quantization; Part II. Stochastic Processes: 7. Stochastic systems; Part III. Discrete Degrees of Freedom: 8. Ising model; 9. Ising model: magnetic field; 10. Fermions; Part IV. Quadratic Path Integrals: 11. Simple harmonic oscillators; 12. Gaussian path integrals; Part V. Action with Acceleration: 13. Acceleration Lagrangian; 14. Pseudo-Hermitian Euclidean Hamiltonian; 15. Non-Hermitian Hamiltonian: Jordan blocks; 16. The quartic potential: instantons; 17. Compact degrees of freedom; Index.

  20. Path Problems in Networks

    CERN Document Server

    Baras, John

    2010-01-01

    The algebraic path problem is a generalization of the shortest path problem in graphs. Various instances of this abstract problem have appeared in the literature, and similar solutions have been independently discovered and rediscovered. The repeated appearance of a problem is evidence of its relevance. This book aims to help current and future researchers add this powerful tool to their arsenal, so that they can easily identify and use it in their own work. Path problems in networks can be conceptually divided into two parts: A distillation of the extensive theory behind the algebraic path pr

  1. Sustainable Energy Path

    Directory of Open Access Journals (Sweden)

    Hiromi Yamamoto

    2005-12-01

    Full Text Available The uses of fossil fuels cause not only the resources exhaustion but also the environmental problems such as global warming. The purposes of this study are to evaluate paths toward sustainable energy systems and roles of each renewable. In order to realize the purposes, the authors developed the global land use and energy model that figured the global energy supply systems in the future considering the cost minimization. Using the model, the authors conducted a simulation in C30R scenario, which is a kind of strict CO2 emission limit scenarios and reduced CO2 emissions by 30% compared with Kyoto protocol forever scenario, and obtained the following results. In C30R scenario bioenergy will supply 33% of all the primary energy consumption. However, wind and photovoltaic will supply 1.8% and 1.4% of all the primary energy consumption, respectively, because of the limits of power grid stability. The results imply that the strict limits of CO2 emissions are not sufficient to achieve the complete renewable energy systems. In order to use wind and photovoltaic as major energy resources, we need not only to reduce the plant costs but also to develop unconventional renewable technologies.

  2. 科技融资模式选择路径研究%The Path Choice of Science and Technology Financing Mode

    Institute of Scientific and Technical Information of China (English)

    林琳; 张忠宇; 刘波

    2014-01-01

    Science -and -technological enterprises face multiple financing challenges during their start -up periods,and these challenges are inevitable due to the large amounts of early investment and high risks.On a global scale,most devel-oped countries have already used effective financing models to solve the financing problems of high -tech companies.How-ever,the development of technology financing in China is still at its early stage.This paper explores the means and methods used to choose technology financing models in three developed countries,the United States,Japan and Germany.Based on the results,the paper analyzes the models built by theories of different technology financing models,and proves that the technology financing model is highly relevant to the level of development of the economic body’s economy and finance,as well as to the level of decision -making and management of the investment body in the society.Most importantly,this pa-per presents suggestions for further development and improvement of China’s technology financing models.%科技企业初创期资金投入大、风险高等特点决定了其在融资方面必然面临诸多问题。从全球范围看,多数发达国家已经采取了适合有效的科技融资模式化解高科技企业融资难题。我国科技融资的发展尚处于初级阶段,为此文章深入研究并比较美、日、德三个发达国家的科技融资模式,构建科技融资模式的理论选择模型,经过分析,得到科技融资模式的选择与经济主体的经济金融发展水平密切相关、与其社会中投资主体的决策水平和管理能力密切相关的结论,为进一步完善我国科技融资模式提供借鉴。

  3. Multi-Dimensional Path Queries

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    1998-01-01

    We present the path-relationship model that supports multi-dimensional data modeling and querying. A path-relationship database is composed of sets of paths and sets of relationships. A path is a sequence of related elements (atoms, paths, and sets of paths). A relationship is a binary path...... to create nested path structures. We present an SQL-like query language that is based on path expressions and we show how to use it to express multi-dimensional path queries that are suited for advanced data analysis in decision support environments like data warehousing environments...

  4. 基于时序路径的FPGA时序分析技术研究%Research of FPGA Timing Sequence Analysis Technology Based on Timing Sequence Path

    Institute of Scientific and Technical Information of China (English)

    周珊; 王金波; 王晓丹

    2016-01-01

    For the significance of high reliable FPGA test timing sequence analysis technology on Spaceflight , depending on the FPGA design and test experience for several years ,timing sequence analysis technology is analyzed deeply ,and a set of feasible solution is extracted ,and the analysis target of timing sequence analysis is clarified . The interface signal timing sequence calculation rules of timing sequence analysis and analysis rules of timing sequence test results are presented by the main method of timing sequence analysis technology ;this set of technology is applied successfully on the tests of several high reliable software on Spaceflight ,many significant functional disabled problems ,caused by timing sequence problems ,can be found ,and the common timing sequence problems are classified and summarized .%针对于航天高可靠FPGA测试时时序分析技术的重要性 ,根据多年FPGA设计测试经验对时序分析技术进行深入剖析 ,提炼出一套切实可行的时序分析技术 ,阐明了时序分析的分析对象 ,时序分析技术的主要方法 ,给出了时序分析时接口信号时序计算法则 ,以及时序测试结果的分析准则 ;并把这套分析技术成功的应用到了多个航天高可靠软件的测试中 ,发现了很多由时序问题引起功能失效的重大问题 ,对其中常见的时序问题给予归类总结 .

  5. Entrepreneurs Technological Progress Path Selection and Economic Growth%企业家技术进步路径选择与经济增长

    Institute of Scientific and Technical Information of China (English)

    唐国华

    2014-01-01

    The faster the speed of knowledge and technological progress, the more benefits of technology imitation can be re-ceived by the developing countries and also the higher economic growth rate. The closer to the cutting edge of technology in developed countries, the greater role of innovative entrepreneurs, the farther from the cutting edge of technology in developing countries, the greater role of imitation entrepreneurs. Entrepreneurs in developing countries accumulate human and physical capital through knowledge filtration, absorption, imitation, learning by doing, and they also accumulate strength for independent innovation to be able to achieve a positive interaction between imitate innovation and independent innovation eventually.%发达国家的知识和技术进步速度越快,发展中国家越是能收到技术模仿的好处,从而带来较高的经济增长率。越是接近技术前沿的发达国家,创新型企业家的作用越大,离技术前沿越远的发展中国家,模仿型企业家的作用往往更明显。发展中国家的企业家通过知识过滤、吸收、模仿、“干中学”,不断积累人力资本和物质资本,为自主创新积蓄力量,最终能实现模仿式创新和自主创新的良性互动。

  6. Unique Path Partitions

    DEFF Research Database (Denmark)

    Bessenrodt, Christine; Olsson, Jørn Børling; Sellers, James A.

    2013-01-01

    We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions.......We give a complete classification of the unique path partitions and study congruence properties of the function which enumerates such partitions....

  7. Path dependence and creation

    DEFF Research Database (Denmark)

    Garud, Raghu; Karnøe, Peter

    the place of agency in these theories that take history so seriously. In the end, they are as interested in path creation and destruction as they are in path dependence. This book is compiled of both theoretical and empirical writing. It shows relatively well-known industries such as the automobile...

  8. 淮北水稻持续高产技术途径探讨%Discuss on Technology Paths of Sustained High Production on Rice in Huaibei

    Institute of Scientific and Technical Information of China (English)

    邱友凤

    2013-01-01

    For more than 10 years, the main reasons on stagnant of rice yield in Jiangsu were expounded exception of lacking new rice varieties on eurytopicity and big yield improving potential, the suitable sets of planting technology were inadequate because of exist alongside traditional cultivation technique, plastic-plate-throwing transplantation, mechanized seeding technology and direct sowing, they were obstacle to increase the yield. the test of traditional cultivation tech-nique, plastic-plate-throwing transplantation, mechanized seeding technology and direct sowing were made discuss efficient ways to increase yield, solve the questions such as contradiction of produce season between rice and wheat, Water short-age, farmland capital construction were lagged, lack the huge work force et al.%江苏省十多年来水稻单产一直徘徊不前,其主要原因除缺乏广适的、增产潜力大的水稻新品种外,在栽培技术上,由于传统手栽、塑盘抛秧、机械栽插、直播等多种栽培方式并存,导致高产栽培配套技术应用不能到位,已成为进一步提升全省水稻单产的障碍。本文通过对手栽、塑盘抛秧、机械栽插、直播等多种栽培方式的试验研究,探讨淮北稻区水稻持续高产技术途径,解决该区稻麦周年生产季节矛盾突出,时常干旱缺水,农田基本建设脆弱,务农劳力匮乏等问题。

  9. Fossil furnace with solar support. Part 1. Paths towards a forward-looking plant technology; Fossile Heizkessel mit solarer Unterstuetzung. Teil 1. Wege zu einer zukunftsfaehigen Anlagentechnik

    Energy Technology Data Exchange (ETDEWEB)

    Wagnitz, M. [Zentralverband Sanitaer Heizung Klima, Potsdam (Germany)

    2007-03-15

    Kyoto, climate targets, energy price discussions - the list of keywords is long. However the effects are mostly unclear. The only thing, which is for sure, nothing will remain as it is.This three-part series explains, how the different heating systems can be incorporated into the logic of the new Regulation for Renewable Energy and into which direction the development in the field of plant technology will go. Different systems for one-family houses are compared with each other as an example. (orig.)

  10. Free path groupoid grading on Leavitt path algebras

    OpenAIRE

    Goncalves, Daniel; Yoneda, Gabriela

    2015-01-01

    In this work we realize Leavitt path algebras as partial skew groupoid rings. This yields a free path groupoid grading on Leavitt path algebras. Using this grading we characterize free path groupoid graded isomorphisms of Leavitt path algebras that preserves generators.

  11. The Path Selection of Small and Medium Enterprises Technology Innovation Legal Protection%中小企业技术创新法律保障的路径选择

    Institute of Scientific and Technical Information of China (English)

    张晓玲

    2012-01-01

    The small and medium enterprises (SEMs) have more superiorities than big enterprises in technology innovation, at the same time,they have many defects. The impeccable legal system is the important insurance for SMEs to make use of superiorities and overcome difficulties. The essay manages present laws by investigating the legal environment of foreign SEMs technology innovation. The ultimate goal is to select the effective legal protection that centers on special law, focuses on the adjustment and innovation of supporting laws and regulations. And the key of path is the advancement of local regulations and policies.%中小企业较之大型企业具有技术创新方面的诸多优势,但也存在不利于其发展的种种因素.完善的法律体系是中小企业利用自身优势和克服发展瓶颈进行技术创新的重要保障.通过考察国外中小企业技术创新的法律环境,梳理我国现有法律法规政策,选择出以专门法为中心,以相关配套法律法规调适与创新为重点,以地方政府法规政策推进为关键的法律保障路径.

  12. Zero-Slack, Noncritical Paths

    Science.gov (United States)

    Simons, Jacob V., Jr.

    2017-01-01

    The critical path method/program evaluation and review technique method of project scheduling is based on the importance of managing a project's critical path(s). Although a critical path is the longest path through a network, its location in large projects is facilitated by the computation of activity slack. However, logical fallacies in…

  13. 郑州市科技与金融结合的路径及政策取向研究%Integration Path Between Technology and Finance and the Policy Orientation in Zhengzhou

    Institute of Scientific and Technical Information of China (English)

    谷秀娟; 梁润平

    2013-01-01

      The financing needs of high tech SMEs in Zhengzhou are characterized by high demand and small amount. The financing channel of the SMEs is single with high threshold and cost,difficult to obtain access to venture investment and government funding sup-port. The government should learn from the paths of the United States through which fiscal finance and financial intermediaries supply fund for technology,technology supplies techniques for finance,and learn from the advanced experience of domestic technology and fi-nance integration. In addition,based on the financing needs of SMEs and the status quo of technology and finance,Zhengzhou govern-ment should formulate relevant policies in fostering main technological innovation bodies,broadening the financing channels of technology companies,and completing the support system in an effort to facilitate the science and finance combination,enhance enterprises' inde-pendent innovation capability,and develop emerging strategic industries.%  目前,郑州市科技型中小企业融资需求呈现的特点是高需求、小额度的特点;融资渠道单一,门槛和成本过高,难以获得风险投资以及政府资金的扶持。郑州市应借鉴美国财政性金融对科技的资金供给、金融中介资金供给、科技对金融的技术供给等路径,以及国内科技与金融结合路径的先进经验,结合郑州市科技型中小企业融资需求特点以及科技金融结合的现状,从培育科技创新资金的供给主体、拓宽科技企业融资渠道、健全支撑体系等方面制定相关政策,努力做好科技与金融的结合工作,增强企业的自主创新能力,培育和发展新兴战略产业。

  14. Tortuous path chemical preconcentrator

    Science.gov (United States)

    Manginell, Ronald P.; Lewis, Patrick R.; Adkins, Douglas R.; Wheeler, David R.; Simonson, Robert J.

    2010-09-21

    A non-planar, tortuous path chemical preconcentrator has a high internal surface area having a heatable sorptive coating that can be used to selectively collect and concentrate one or more chemical species of interest from a fluid stream that can be rapidly released as a concentrated plug into an analytical or microanalytical chain for separation and detection. The non-planar chemical preconcentrator comprises a sorptive support structure having a tortuous flow path. The tortuosity provides repeated twists, turns, and bends to the flow, thereby increasing the interfacial contact between sample fluid stream and the sorptive material. The tortuous path also provides more opportunities for desorption and readsorption of volatile species. Further, the thermal efficiency of the tortuous path chemical preconcentrator is comparable or superior to the prior non-planar chemical preconcentrator. Finally, the tortuosity can be varied in different directions to optimize flow rates during the adsorption and desorption phases of operation of the preconcentrator.

  15. Career Path Descriptions

    CERN Document Server

    Charkiewicz, A

    2000-01-01

    Before the Career Path system, jobs were classified according to grades with general statutory definitions, guided by the "Job Catalogue" which defined 6 evaluation criteria with example illustrations in the form of "typical" job descriptions. Career Paths were given concise statutory definitions necessitating a method of description and evaluation adapted to their new wider-band salary concept. Evaluations were derived from the same 6 criteria but the typical descriptions became unusable. In 1999, a sub-group of the Standing Concertation Committee proposed a new guide for describing Career Paths, adapted to their wider career concept by expanding the 6 evaluation criteria into 9. For each criterion several levels were established tracing the expected evolution of job level profiles and personal competencies over their longer salary ranges. While providing more transparency to supervisors and staff, the Guide's official use would be by services responsible for vacancy notices, Career Path evaluations and rela...

  16. Path Optimization Using APSO

    Directory of Open Access Journals (Sweden)

    Deepak Goyal

    2013-07-01

    Full Text Available This paper addresses the malicious node detection and path optimization problem for wireless sensor networks. Malicious node detection in neighborhood is a needed because that node may cause incorrect decisions or energy depletion. In this paper APSO (combination of Artificial bee colony and particular swarm optimization is used to choose an optimized path. Through this improved version we will overcome the disadvantage of local optimal which comes when we use PSO approach.

  17. Paths to nursing leadership.

    Science.gov (United States)

    Bondas, Terese

    2006-07-01

    The aim was to explore why nurses enter nursing leadership and apply for a management position in health care. The study is part of a research programme in nursing leadership and evidence-based care. Nursing has not invested enough in the development of nursing leadership for the development of patient care. There is scarce research on nurses' motives and reasons for committing themselves to a career in nursing leadership. A strategic sample of 68 Finnish nurse leaders completed a semistructured questionnaire. Analytic induction was applied in an attempt to generate a theory. A theory, Paths to Nursing Leadership, is proposed for further research. Four different paths were found according to variations between the nurse leaders' education, primary commitment and situational factors. They are called the Path of Ideals, the Path of Chance, the Career Path and the Temporary Path. Situational factors and role models of good but also bad nursing leadership besides motivational and educational factors have played a significant role when Finnish nurses have entered nursing leadership. The educational requirements for nurse leaders and recruitment to nursing management positions need serious attention in order to develop a competent nursing leadership.

  18. The effect of varying path properties in path steering tasks

    NARCIS (Netherlands)

    Liu, L.; Liere, R. van

    2010-01-01

    Path steering is a primitive 3D interaction task that requires the user to navigate through a path of a given length and width. In a previous paper, we have conducted controlled experiments in which users operated a pen input device to steer a cursor through a 3D path subject to fixed path propertie

  19. Shortest Paths in Microseconds

    CERN Document Server

    Agarwal, Rachit; Godfrey, P Brighten; Zhao, Ben Y

    2013-01-01

    Computing shortest paths is a fundamental primitive for several social network applications including socially-sensitive ranking, location-aware search, social auctions and social network privacy. Since these applications compute paths in response to a user query, the goal is to minimize latency while maintaining feasible memory requirements. We present ASAP, a system that achieves this goal by exploiting the structure of social networks. ASAP preprocesses a given network to compute and store a partial shortest path tree (PSPT) for each node. The PSPTs have the property that for any two nodes, each edge along the shortest path is with high probability contained in the PSPT of at least one of the nodes. We show that the structure of social networks enable the PSPT of each node to be an extremely small fraction of the entire network; hence, PSPTs can be stored efficiently and each shortest path can be computed extremely quickly. For a real network with 5 million nodes and 69 million edges, ASAP computes a short...

  20. Faster Replacement Paths

    CERN Document Server

    Williams, Virginia Vassilevska

    2010-01-01

    The replacement paths problem for directed graphs is to find for given nodes s and t and every edge e on the shortest path between them, the shortest path between s and t which avoids e. For unweighted directed graphs on n vertices, the best known algorithm runtime was \\tilde{O}(n^{2.5}) by Roditty and Zwick. For graphs with integer weights in {-M,...,M}, Weimann and Yuster recently showed that one can use fast matrix multiplication and solve the problem in O(Mn^{2.584}) time, a runtime which would be O(Mn^{2.33}) if the exponent \\omega of matrix multiplication is 2. We improve both of these algorithms. Our new algorithm also relies on fast matrix multiplication and runs in O(M n^{\\omega} polylog(n)) time if \\omega>2 and O(n^{2+\\eps}) for any \\eps>0 if \\omega=2. Our result shows that, at least for small integer weights, the replacement paths problem in directed graphs may be easier than the related all pairs shortest paths problem in directed graphs, as the current best runtime for the latter is \\Omega(n^{2.5...

  1. 我国企业复杂技术创新能力研究:基于三维模型的成长路径%A Study on Complex Technology Innovation Capability of Chinese Firms: A Three-Dimension Model Perspective based on Evolutionary Paths WT

    Institute of Scientific and Technical Information of China (English)

    王毅

    2011-01-01

    Complex technology industries will play important roles in the economic prosperity of China. This paper explores key dimensions of complex technology innovation capability according to complex technology characteristics and addresses the evolutionary paths of a firm's complex technology innovation capability.This paper investigates three business cases on communications system equipment, shipbuilding and automobile industries. This paper makes three major academic contributions. First, this study advances our understanding of the three-is intension model of complex technology innovation capability, including systems technology innovation capability, core technology innovation capability, and industry chain innovation capability. Second, three evolutionary paths of a firm's complex technology innovation capability are discovered. The first path moves from core technology innovation capability to systems technology innovation capability, and then industry chain innovation capability. The second path moves from systems technology innovation capability to core technology innovation capability and then to industry chain innovation capability. The third path moves from systems technology innovation capability and core technology innovation capability to industry chain innovation capability. Third, we identify important driving forces for different evolutionary paths of a firm's complex technology innovation capability. These forces include market characteristics, technology characteristics, organizational characteristics, and the speed and scope of a firm's complex technology innovation capability.%我国经济强国之路需要复杂技术产业的创新和发展.本文针对复杂技术的特点来解构复杂技术创新能力的维度构成,并结合后发国家特点从企业层面来探讨复杂技术创新能力演化的路径.本文对我国通信系统设备、造船和汽车产业三家企业的复杂技术创新能力成长路径进行了案例研究.

  2. Smoothing of Piecewise Linear Paths

    Directory of Open Access Journals (Sweden)

    Michel Waringo

    2008-11-01

    Full Text Available We present an anytime-capable fast deterministic greedy algorithm for smoothing piecewise linear paths consisting of connected linear segments. With this method, path points with only a small influence on path geometry (i.e. aligned or nearly aligned points are successively removed. Due to the removal of less important path points, the computational and memory requirements of the paths are reduced and traversing the path is accelerated. Our algorithm can be used in many different applications, e.g. sweeping, path finding, programming-by-demonstration in a virtual environment, or 6D CNC milling. The algorithm handles points with positional and orientational coordinates of arbitrary dimension.

  3. TRACING EFFICIENT PATH USING WEB PATH TRACING

    Directory of Open Access Journals (Sweden)

    L.K. Joshila Grace

    2014-01-01

    Full Text Available In the fast improving society, people depend on online purchase of goods than spending time physically. So there are lots of resources emerged for this online buying and selling of materials. Efficient and attractive web sites would be the best to sell the goods to people. To know whether a web site is reaching the mind of the customers or not, a high speed analysis is done periodically by the web developers. This works helps for the web site developers in knowing the weaker and stronger section of their web site. Parameters like frequency and utility are used for quantitative and qualitative analysis respectively. Addition to this down loads, book marks and the like/dislike of the particular web site is also considered. A new web path trace tree structure is implemented. A mathematical implementation is done to predict the efficient pattern used by the web site visitors.

  4. Euclidean shortest paths

    CERN Document Server

    Li, Fajie

    2011-01-01

    This unique text/reference reviews algorithms for the exact or approximate solution of shortest-path problems, with a specific focus on a class of algorithms called rubberband algorithms. Discussing each concept and algorithm in depth, the book includes mathematical proofs for many of the given statements. Topics and features: provides theoretical and programming exercises at the end of each chapter; presents a thorough introduction to shortest paths in Euclidean geometry, and the class of algorithms called rubberband algorithms; discusses algorithms for calculating exact or approximate ESPs i

  5. 六盘水市农业科技园区发展现状、问题及路径选择%THE ISSUE AND PATH SELECTION OF THE AGRICULTURE SCIENCE AND TECHNOLOGY PARK OF LIUPANSHUI CITY

    Institute of Scientific and Technical Information of China (English)

    饶华敏

    2015-01-01

    not yet formed a complete construction of the park system. Therefore, Liupanshui City Agricultural Science and Technology Park Problems and route selection research has im-portant practical significance. The study from the investment, operating efficiency, supporting infrastructure, lead-ing industry development, training and other business entities in five aspects of the status of agricultural science and technology park development in Liupanshui city of analysis, the management and the level of infrastructure develop-ment, working capital management, industrialization of agriculture development, talent introduction and training, market-oriented system, the presence of the six aspects of construction, constructed with a Liupanshui characteris-tics, the province's leading domestic first-class modern and efficient agricultural science and technology park de-velopment ideas, And proposed the development of efficient ecological agriculture and mountainous characteristic three-dimensional agriculture, industrial chain extension of the park and develop brand agriculture, diversified business model park three major development path, to provide some reference for further construction work Liupan-shui City of agricultural science and technology park, for the industrialization of agriculture has played a positive role in promoting.%我国存在粮食短缺、环境污染及资源匮乏等问题,这些问题使得传统的粗放型农业生产方式面临极大的挑战,故向集约、高效的现代化生产方向转变成为我国农业发展的必然趋势.目前,以农业高新技术为支撑的农业科技园区对于地区农业产业的发展起到积极的辐射带动作用.文章从投资情况、经营效益及主导产业发展情况、经营主体培育现状等3个方面对六盘水市农业科技园区发展现状进行分析,发现其在管理模式及水平、基础设施建设、运营资金管理、农业产业化发展、人才引进与培

  6. An Unplanned Path

    Science.gov (United States)

    McGarvey, Lynn M.; Sterenberg, Gladys Y.; Long, Julie S.

    2013-01-01

    The authors elucidate what they saw as three important challenges to overcome along the path to becoming elementary school mathematics teacher leaders: marginal interest in math, low self-confidence, and teaching in isolation. To illustrate how these challenges were mitigated, they focus on the stories of two elementary school teachers--Laura and…

  7. Reparametrizations of Continuous Paths

    DEFF Research Database (Denmark)

    Fahrenberg, Uli; Raussen, Martin

    2007-01-01

    compare it to the distributive lattice of countable subsets of the unit interval. The results obtained are used to analyse the space of traces in a topological space, i.e., the space of continuous paths up to reparametrization equivalence. This space is shown to be homeomorphic to the space of regular...

  8. MEASURING PATH DEPENDENCY

    Directory of Open Access Journals (Sweden)

    Peter Juhasz

    2017-03-01

    Full Text Available While risk management gained popularity during the last decades even some of the basic risk types are still far out of focus. One of these is path dependency that refers to the uncertainty of how we reach a certain level of total performance over time. While decision makers are careful in accessing how their position will look like the end of certain periods, little attention is given how they will get there through the period. The uncertainty of how a process will develop across a shorter period of time is often “eliminated” by simply choosing a longer planning time interval, what makes path dependency is one of the most often overlooked business risk types. After reviewing the origin of the problem we propose and compare seven risk measures to access path. Traditional risk measures like standard deviation of sub period cash flows fail to capture this risk type. We conclude that in most cases considering the distribution of the expected cash flow effect caused by the path dependency may offer the best method, but we may need to use several measures at the same time to include all the optimisation limits of the given firm

  9. 企业技术创新路径依赖的盛宴与陷阱研究——以福特公司为例%Feast with the Trap on the Path-dependence of Technological Innovation——Take the Ford Motor Company for Example

    Institute of Scientific and Technical Information of China (English)

    刘亦文; 胡宗义

    2011-01-01

    This paper analysis the Model T Ford era of technological innovation path-dependent feast with a trap from product design, production technology, low cost strategies, organization and management. It finds out the final factors that affect ford the success or failure of its technological innovation because of path dependence. So, look for enterprises to overcome the path-dependent response and business development strategies for the management of enterprises in technological innovation has an important and far-reaching significance.%从产品设计、生产技术、低价战略及组织和管理等方面,分析了T型车时代的福特汽车企业技术创新路径依赖的盛宴与陷阱,找出了福特汽车因路径依赖最终影响其技术创新成败的因素.因此,寻找企业突破路径依赖的对策与发展战略,对企业的技术创新管理具有重要而深远的意义.

  10. 后金融危机时代科技型企业技术能力提升路径——基于战略创新视角的研究%Research on the Path of Improving Technical Capacity of Science and Technology Enterprises in Post- crisis Era——from the Perspective of Strategic Innovation

    Institute of Scientific and Technical Information of China (English)

    周霞; 陈骁聪; 景保峰

    2011-01-01

    For economic development, it is both a challenge and an opportunity in post - crisis era. First, this paper studies on the concept of technical capabilities of science and technology enterprises and explores the general path of improving technical capabilities. However, the general path isn' t perfect. With strategic innovation, an ideal path is found, which is important to the development of science and technology enterprises. In the end, operating mechanism of the ideal path is introduced.%后金融危机时代的到来对中国经济发展既是一种挑战,也是一种机遇.首先探讨了科技型企业技术能力的内涵和一般发展提升路径.基于普通的提升路径并不适应后金融危机时代科技型企业的发展需要,从战略创新的视角出发,得出科技型企业技术能力提升的理想路径,并阐述其内在运行机理,对我国科技型企业发展提供战略参考.

  11. 提高粮食综合生产能力的技术路径——以河南省为例%Technological Paths for Improving Grain Comprehensive Productivity ——Taking Henan Province for Instance

    Institute of Scientific and Technical Information of China (English)

    解宗方; 张伟

    2011-01-01

    [目的]根据河南省情和生产实际,探讨提高粮食生产能力的技术路径。[方法]对河南省粮食产量的现状与动态进行整体分析。[结果]河南省粮食总产量的变化呈现上升态势。2010年粮食总产5437万t是1978年粮食总产2097.40万t的2.5倍。粮食总产的增长越来越依赖于单产的提高。[结论]该研究为河南省乃至全国粮食增产提供理论依据。%[Objective] This paper aimed at exploring technological paths for improving grain productivity based on the conditions and production practice in Henan Province.[Method] The status and dynamics of grain production in Henan Province were analyzed as a whole.[Result] The total production of grain in Henan Province had generally shown a tendency of ascent.Total grain production in Henan Province was 54 370 thousand t,which was 2.5 times of the total grain production in 1978,as 20 974 thousand t.The growth of grain production was more and more relying on the improvement of grain yield per unit area.[Conclusion] This research had provided theoretical basis for the improvement of grain production in Henan Province as well as for the grain production of the whole country.

  12. Path Dependency and Path Plasticity: the Co-evolution of Institutions and Innovation - the German Customized Business Software Industry

    OpenAIRE

    Strambach, Simone (Prof. Dr.)

    2008-01-01

    Path dependence and the co-evolution of technology and institutions is a key concept to understand the dynamics of structural change at the level of firms, sectors and multi-level spatial scales. The concept of path dependency is often used in economic geography to explain the economic specialisation and long-standing success as well as crises and economically unfavourable development of regions. The understanding of the institutional dynamics within a well-established technological and insti...

  13. 切入寡头垄断市场的技术创业路径分析——以博亚机械为例%Analysis of Technology Entrepreneurship Path in Oligarchic Monopoly Market ——A Case Study of Boya Precision Industrial Equipments Co.Ltd

    Institute of Scientific and Technical Information of China (English)

    李文喜

    2011-01-01

    The paper summarizes the characteristics of oligarchic monopoly market, analyzes the technology entrepreneurship path under the oligarchic monopoly market based on the existing literature.The paper takes the Boya Precision Industrial Equipments Co.Ltd as an example, researches the import substitution of technology entrepreneurship path under the oligarchic monopoly market, and discusses the impact of their entrepreneurial success factors.%从寡头垄断市场特点入手,在已有文献的基础上,分析了适合寡头垄断市场的技术创业路径.以襄阳博亚机械有限公司为例,探析了切入寡头垄断市场的技术引领型进口替代技术创业路径,并系统讨论了影响其创业成功的关键因素.

  14. Cosmological Feynman Paths

    CERN Document Server

    Chew, Geoffrey F

    2008-01-01

    Arrowed-time divergence-free rules or cosmological quantum dynamics are formulated through stepped Feynman paths across macroscopic slices of Milne spacetime. Slice boundaries house totally-relativistic rays representing elementary entities--preons. Total relativity and the associated preon Fock space, despite distinction from special relativity (which lacks time arrow), are based on the Lorentz group. Each path is a set of cubic vertices connected by straight, directed and stepped arcs that carry inertial, electromagnetic and gravitational action. The action of an arc step comprises increments each bounded by Planck's constant. Action from extremely-distant sources is determined by universe mean energy density. Identifying the arc-step energy that determines inertial action with that determining gravitational action establishes both arc-step length and universe density. Special relativity is accurate for physics at laboratory spacetime scales far below that of Hubble and far above that of Planck.

  15. Nonadiabatic transition path sampling

    Science.gov (United States)

    Sherman, M. C.; Corcelli, S. A.

    2016-07-01

    Fewest-switches surface hopping (FSSH) is combined with transition path sampling (TPS) to produce a new method called nonadiabatic path sampling (NAPS). The NAPS method is validated on a model electron transfer system coupled to a Langevin bath. Numerically exact rate constants are computed using the reactive flux (RF) method over a broad range of solvent frictions that span from the energy diffusion (low friction) regime to the spatial diffusion (high friction) regime. The NAPS method is shown to quantitatively reproduce the RF benchmark rate constants over the full range of solvent friction. Integrating FSSH within the TPS framework expands the applicability of both approaches and creates a new method that will be helpful in determining detailed mechanisms for nonadiabatic reactions in the condensed-phase.

  16. PATHS groundwater hydrologic model

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.W.; Schur, J.A.

    1980-04-01

    A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

  17. Path planning in dynamic environments

    NARCIS (Netherlands)

    Berg, J.P. van den

    2007-01-01

    Path planning plays an important role in various fields of application, such as CAD design, computer games and virtual environments, molecular biology, and robotics. In its most general form, the path planning problem is formulated as finding a collision-free path for a moving entity between a start

  18. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  19. 反应热压制备TiC/Al复合材料的形成途径研究%Investigation on Formation Path of TiC/Al Composite Obtained by Reactive Hot-pressing Technology

    Institute of Scientific and Technical Information of China (English)

    宋谋胜; 冉茂武

    2012-01-01

    利用场激发反应热压合成技术研究了Al-Ti-C混合粉末体系制备TiC/Al产物的过程与致密性,并结合DSC实验分析了该体系合成TiC相的形成途径.结果表明,采用反应热压合成法完全能够制备较致密的TiC/Al复合材料.该体系形成TiC相的反应过程为:Ti(s)+3Al(s)=TiAl3(s)→Al(s)=Al(l) →Ti(s)+3 Al(l)=TiAl3(s)→ TiAl3(s)=TiAl3(1)→TiAl3(l)+C(s)=TiC(s)+ Al((l)).混合粉末中的Al不仅作为稀释剂降低体系的反应温度而细化TiC晶粒,还作为反应剂参与了整个反应进程.%Utilizing the field activation reactive hot-pressing (RHP) technology, the process and densificatian of TiC/Al products obtained from Al-Ti-C mixtures system were investigated, eoupied with the DSC experiment to analyze iht formation path of TiC phase in this system. The results show that the dense TiC/Al composite can be fully fabricated by the reactive hot-pressing method. The reaction process of the Al-Ti-C system to form TiC phase can be expressed: Ti(s)+3Al(s)= TiAl3(s) →Al(s)=Al(1)→Ti(,s)+3Al(1)=TiAl,(s)→TiAl3(s)=TiAl3(1)→TiAl3(l)+C(s)=T(C(s)+Al(1). Al in the mixtures plays an important role in serving not only as a diluent to decrease the reaction temperature and thus to refine the TiC grains, but also as an intermediate reactant to participate in the whole reaction process.

  20. Integrated assignment and path planning

    Science.gov (United States)

    Murphey, Robert A.

    2005-11-01

    A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact

  1. Lexicographic Path Induction

    DEFF Research Database (Denmark)

    Schürmann, Carsten; Sarnat, Jeffrey

    2009-01-01

    Programming languages theory is full of problems that reduce to proving the consistency of a logic, such as the normalization of typed lambda-calculi, the decidability of equality in type theory, equivalence testing of traces in security, etc. Although the principle of transfinite induction...... an induction principle that combines the comfort of structural induction with the expressive strength of transfinite induction. Using lexicographic path induction, we give a consistency proof of Martin-Löf’s intuitionistic theory of inductive definitions. The consistency of Heyting arithmetic follows directly...

  2. JAVA PathFinder

    Science.gov (United States)

    Mehhtz, Peter

    2005-01-01

    JPF is an explicit state software model checker for Java bytecode. Today, JPF is a swiss army knife for all sort of runtime based verification purposes. This basically means JPF is a Java virtual machine that executes your program not just once (like a normal VM), but theoretically in all possible ways, checking for property violations like deadlocks or unhandled exceptions along all potential execution paths. If it finds an error, JPF reports the whole execution that leads to it. Unlike a normal debugger, JPF keeps track of every step how it got to the defect.

  3. Rocket Flight Path

    Directory of Open Access Journals (Sweden)

    Jamie Waters

    2014-09-01

    Full Text Available This project uses Newton’s Second Law of Motion, Euler’s method, basic physics, and basic calculus to model the flight path of a rocket. From this, one can find the height and velocity at any point from launch to the maximum altitude, or apogee. This can then be compared to the actual values to see if the method of estimation is a plausible. The rocket used for this project is modeled after Bullistic-1 which was launched by the Society of Aeronautics and Rocketry at the University of South Florida.

  4. Path Through the Wheat

    Directory of Open Access Journals (Sweden)

    David Middleton

    2005-01-01

    Full Text Available The hillside’s tidal waves of yellow-green Break downward into full-grown stalks of wheat In which a peasant, shouldering his hoe Passes along a snaking narrow path -- A teeming place through which his hard thighs press And where his head just barely stays above The swaying grain, drunken in abundance, Farm buildings almost floating on the swells Beyond which sea gulls gliding white in air Fly down on out of sight to salty fields, Taking the channel fish off Normandy, A surfeit fit for Eden i...

  5. Technology

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2016-01-01

    Full Text Available The traditional answer card reading method using OMR (Optical Mark Reader, most commonly, OMR special card special use, less versatile, high cost, aiming at the existing problems proposed a method based on pattern recognition of the answer card identification method. Using the method based on Line Segment Detector to detect the tilt of the image, the existence of tilt image rotation correction, and eventually achieve positioning and detection of answers to the answer sheet .Pattern recognition technology for automatic reading, high accuracy, detect faster

  6. Path Integrals in Quantum Physics

    CERN Document Server

    Rosenfelder, R

    2012-01-01

    These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical evaluation of (euclidean) path integrals by Monte-Carlo methods with a program for the anharmonic oscillator. The second part deals with the application of path integrals in statistical mechanics and many-body problems treating the polaron problem, dissipative quantum systems, path integrals over ordinary and Grassmannian coherent states and perturbation theory for both bosons and fermions. Again a simple Fortran program is included for illustrating the use of strong-coupling methods. Finally, in the third part path integra...

  7. Shortest Paths and Vehicle Routing

    DEFF Research Database (Denmark)

    Petersen, Bjørn

    This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle R...... Routing Problem based on partial paths is presented. Finally, a practical application of finding shortest paths in the telecommunication industry is shown.......This thesis presents how to parallelize a shortest path labeling algorithm. It is shown how to handle Chvátal-Gomory rank-1 cuts in a column generation context. A Branch-and-Cut algorithm is given for the Elementary Shortest Paths Problem with Capacity Constraint. A reformulation of the Vehicle...

  8. Path integrals for awkward actions

    CERN Document Server

    Amdahl, David

    2016-01-01

    Time derivatives of scalar fields occur quadratically in textbook actions. A simple Legendre transformation turns the lagrangian into a hamiltonian that is quadratic in the momenta. The path integral over the momenta is gaussian. Mean values of operators are euclidian path integrals of their classical counterparts with positive weight functions. Monte Carlo simulations can estimate such mean values. This familiar framework falls apart when the time derivatives do not occur quadratically. The Legendre transformation becomes difficult or so intractable that one can't find the hamiltonian. Even if one finds the hamiltonian, it usually is so complicated that one can't path-integrate over the momenta and get a euclidian path integral with a positive weight function. Monte Carlo simulations don't work when the weight function assumes negative or complex values. This paper solves both problems. It shows how to make path integrals without knowing the hamiltonian. It also shows how to estimate complex path integrals b...

  9. Propagators and path integrals

    Energy Technology Data Exchange (ETDEWEB)

    Holten, J.W. van

    1995-08-22

    Path-integral expressions for one-particle propagators in scalar and fermionic field theories are derived, for arbitrary mass. This establishes a direct connection between field theory and specific classical point-particle models. The role of world-line reparametrization invariance of the classical action and the implementation of the corresponding BRST-symmetry in the quantum theory are discussed. The presence of classical world-line supersymmetry is shown to lead to an unwanted doubling of states for massive spin-1/2 particles. The origin of this phenomenon is traced to a `hidden` topological fermionic excitation. A different formulation of the pseudo-classical mechanics using a bosonic representation of {gamma}{sub 5} is shown to remove these extra states at the expense of losing manifest supersymmetry. (orig.).

  10. Path integral in Snyder space

    Energy Technology Data Exchange (ETDEWEB)

    Mignemi, S., E-mail: smignemi@unica.it [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy); Štrajn, R. [Dipartimento di Matematica e Informatica, Università di Cagliari, Viale Merello 92, 09123 Cagliari (Italy); INFN, Sezione di Cagliari, Cittadella Universitaria, 09042 Monserrato (Italy)

    2016-04-29

    The definition of path integrals in one- and two-dimensional Snyder space is discussed in detail both in the traditional setting and in the first-order formalism of Faddeev and Jackiw. - Highlights: • The definition of the path integral in Snyder space is discussed using phase space methods. • The same result is obtained in the first-order formalism of Faddeev and Jackiw. • The path integral formulation of the two-dimensional Snyder harmonic oscillator is outlined.

  11. Path indexing for term retrieval

    OpenAIRE

    1992-01-01

    Different methods for term retrieval in deduction systems have been introduced in literature. This report eviews the three indexing techniques discrimination indexing, path indexing, and abstraction tree indexing. A formal approach to path indexing is presented and algorithms as well as data structures of an existing implementation are discussed. Eventually, experiments will show that our implementation outperforms the implementation of path indexing in the OTTER theorem prover.

  12. An introduction to critical paths.

    Science.gov (United States)

    Coffey, Richard J; Richards, Janet S; Remmert, Carl S; LeRoy, Sarah S; Schoville, Rhonda R; Baldwin, Phyllis J

    2005-01-01

    A critical path defines the optimal sequencing and timing of interventions by physicians, nurses, and other staff for a particular diagnosis or procedure. Critical paths are developed through collaborative efforts of physicians, nurses, pharmacists, and others to improve the quality and value of patient care. They are designed to minimize delays and resource utilization and to maximize quality of care. Critical paths have been shown to reduce variation in the care provided, facilitate expected outcomes, reduce delays, reduce length of stay, and improve cost-effectiveness. The approach and goals of critical paths are consistent with those of total quality management (TQM) and can be an important part of an organization's TQM process.

  13. Precision Cleaning - Path to Premier

    Science.gov (United States)

    Mackler, Scott E.

    2008-01-01

    ITT Space Systems Division s new Precision Cleaning facility provides critical cleaning and packaging of aerospace flight hardware and optical payloads to meet customer performance requirements. The Precision Cleaning Path to Premier Project was a 2007 capital project and is a key element in the approved Premier Resource Management - Integrated Supply Chain Footprint Optimization Project. Formerly precision cleaning was located offsite in a leased building. A new facility equipped with modern precision cleaning equipment including advanced process analytical technology and improved capabilities was designed and built after outsourcing solutions were investigated and found lacking in ability to meet quality specifications and schedule needs. SSD cleans parts that can range in size from a single threaded fastener all the way up to large composite structures. Materials that can be processed include optics, composites, metals and various high performance coatings. We are required to provide verification to our customers that we have met their particulate and molecular cleanliness requirements and we have that analytical capability in this new facility. The new facility footprint is approximately half the size of the former leased operation and provides double the amount of throughput. Process improvements and new cleaning equipment are projected to increase 1st pass yield from 78% to 98% avoiding $300K+/yr in rework costs. Cost avoidance of $350K/yr will result from elimination of rent, IT services, transportation, and decreased utility costs. Savings due to reduced staff expected to net $4-500K/yr.

  14. Chromatic roots and hamiltonian paths

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2000-01-01

    We present a new connection between colorings and hamiltonian paths: If the chromatic polynomial of a graph has a noninteger root less than or equal to t(n) = 2/3 + 1/3 (3)root (26 + 6 root (33)) + 1/3 (3)root (26 - 6 root (33)) = 1.29559.... then the graph has no hamiltonian path. This result...

  15. Two Generations of Path Dependence

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

      Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences - primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

  16. Business model innovation paths

    NARCIS (Netherlands)

    Chesbrough, H.; Di Minin, Alberto; Piccaluga, A.

    2013-01-01

    This chapter explains the business model concept and explores the reasons why “innovation” and “innovation in services” are no longer exclusively a technological issue. Rather, we highlight that business models are critical components at the centre of business innovation processes. We also attempt

  17. China's Path Toward Innovation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    @@ China outlined the indigenous innovation strategy in its National Medium-and Long-term Science and Technology Development Plan(2006-20)four years ago.What is the main goal of the strategy and how has it been progressing? What are the Central Government's support policies and what efforts are still needed?

  18. Hard paths, soft paths or no paths? Cross-cultural perceptions of water solutions

    Science.gov (United States)

    Wutich, A.; White, A. C.; White, D. D.; Larson, K. L.; Brewis, A.; Roberts, C.

    2014-01-01

    In this study, we examine how development status and water scarcity shape people's perceptions of "hard path" and "soft path" water solutions. Based on ethnographic research conducted in four semi-rural/peri-urban sites (in Bolivia, Fiji, New Zealand, and the US), we use content analysis to conduct statistical and thematic comparisons of interview data. Our results indicate clear differences associated with development status and, to a lesser extent, water scarcity. People in the two less developed sites were more likely to suggest hard path solutions, less likely to suggest soft path solutions, and more likely to see no path to solutions than people in the more developed sites. Thematically, people in the two less developed sites envisioned solutions that involve small-scale water infrastructure and decentralized, community-based solutions, while people in the more developed sites envisioned solutions that involve large-scale infrastructure and centralized, regulatory water solutions. People in the two water-scarce sites were less likely to suggest soft path solutions and more likely to see no path to solutions (but no more likely to suggest hard path solutions) than people in the water-rich sites. Thematically, people in the two water-rich sites seemed to perceive a wider array of unrealized potential soft path solutions than those in the water-scarce sites. On balance, our findings are encouraging in that they indicate that people are receptive to soft path solutions in a range of sites, even those with limited financial or water resources. Our research points to the need for more studies that investigate the social feasibility of soft path water solutions, particularly in sites with significant financial and natural resource constraints.

  19. 14 CFR 23.57 - Takeoff path.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff path. 23.57 Section 23.57... path. For each commuter category airplane, the takeoff path is as follows: (a) The takeoff path extends... completed; and (1) The takeoff path must be based on the procedures prescribed in § 23.45; (2) The...

  20. Geodesic flows on path spaces

    Institute of Scientific and Technical Information of China (English)

    XIANG; Kainan

    2001-01-01

    [1] Cruzeiro, A. B., Malliavin, P., Renormalized differential geometry on path spaces: Structural equation, curvature, J. Funct. Anal., 1996, 139: 119-181.[2] Stroock, D. W., Some thoughts about Riemannian structures on path spaces, preprint, 1996.[3] Driver, B., A Cameron-Martin type quasi-invariance theorem for Brownian motion on a compact manifold, J. Funct. Anal., 1992, 109: 272-376.[4] Enchev, O., Stroock, D. W., Towards a Riemannian geometry on the path space over a Riemannian manifold, J. Funct. Anal., 1995, 134: 392-416.[5] Hsu, E., Quasi-invariance of the Wiener measure on the path space over a compact Riemannian manifold, J. Funct. Anal., 1995, 134: 417-450.[6] Lyons, T. J., Qian, Z. M., A class of vector fields on path space, J.Funct. Anal., 1997, 145: 205-223.[7] Li, X. D., Existence and uniqueness of geodesics on path spaces, J. Funct. Anal., to be published.[8] Driver, B., Towards calculus and geometry on path spaces, in Proc. Symp. Pure and Appl. Math. 57 (ed. Cranston, M., Pinsky, M.), Cornell: AMS, 1993, 1995.

  1. Path integrals and quantum processes

    CERN Document Server

    Swanson, Marc S

    1992-01-01

    In a clearly written and systematic presentation, Path Integrals and Quantum Processes covers all concepts necessary to understand the path integral approach to calculating transition elements, partition functions, and source functionals. The book, which assumes only a familiarity with quantum mechanics, is ideal for use as a supplemental textbook in quantum mechanics and quantum field theory courses. Graduate and post-graduate students who are unfamiliar with the path integral will also benefit from this contemporary text. Exercise sets are interspersed throughout the text to facilitate self-

  2. Path Integration in Conical Space

    OpenAIRE

    Inomata, Akira; Junker, Georg

    2011-01-01

    Quantum mechanics in conical space is studied by the path integral method. It is shown that the curvature effect gives rise to an effective potential in the radial path integral. It is further shown that the radial path integral in conical space can be reduced to a form identical with that in flat space when the discrete angular momentum of each partial wave is replaced by a specific non-integral angular momentum. The effective potential is found proportional to the squared mean curvature of ...

  3. On the Reaction Path Hamiltonian

    Institute of Scientific and Technical Information of China (English)

    孙家钟; 李泽生

    1994-01-01

    A vector-fiber bundle structure of the reaction path Hamiltonian, which has been introduced by Miller, Handy and Adams, is explored with respect to molecular vibrations orthogonal to the reaction path. The symmetry of the fiber bundle is characterized by the real orthogonal group O(3N- 7) for the dynamical system with N atoms. Under the action of group O(3N- 7). the kinetic energy of the reaction path Hamiltonian is left invariant. Furthermore , the invariant behaviour of the Hamiltonian vector fields is investigated.

  4. Transition Path Theory

    Science.gov (United States)

    vanden-Eijnden, E.

    The dynamical behavior of many systems arising in physics, chemistry, biology, etc. is dominated by rare but important transition events between long lived states. For over 70 years, transition state theory (TST) has provided the main theoretical framework for the description of these events [17,33,34]. Yet, while TST and evolutions thereof based on the reactive flux formalism [1, 5] (see also [30,31]) give an accurate estimate of the transition rate of a reaction, at least in principle, the theory tells very little in terms of the mechanism of this reaction. Recent advances, such as transition path sampling (TPS) of Bolhuis, Chandler, Dellago, and Geissler [3, 7] or the action method of Elber [15, 16], may seem to go beyond TST in that respect: these techniques allow indeed to sample the ensemble of reactive trajectories, i.e. the trajectories by which the reaction occurs. And yet, the reactive trajectories may again be rather uninformative about the mechanism of the reaction. This may sound paradoxical at first: what more than actual reactive trajectories could one need to understand a reaction? The problem, however, is that the reactive trajectories by themselves give only a very indirect information about the statistical properties of these trajectories. This is similar to why statistical mechanics is not simply a footnote in books about classical mechanics. What is the probability density that a trajectory be at a given location in state-space conditional on it being reactive? What is the probability current of these reactive trajectories? What is their rate of appearance? These are the questions of interest and they are not easy to answer directly from the ensemble of reactive trajectories. The right framework to tackle these questions also goes beyond standard equilibrium statistical mechanics because of the nontrivial bias that the very definition of the reactive trajectories imply - they must be involved in a reaction. The aim of this chapter is to

  5. Paths of movement

    DEFF Research Database (Denmark)

    Hansen, Lone Koefoed

    2013-01-01

    As GPS technologies are embedded into mobile devices—and thus everyday life—it has become common to track the location and trajectories of humans as well as objects.While knowing where people and things actually are and have actually been can be interesting, by also engaging with the lives and (hi......, and with theoretical reference to Dutch architect Rem Koolhaas and French theorist Michel de Certeau, this chapter discusses how mobile media seem to facilitate an informed (re)engagement with space and the spatial narratives that unfold when people and objects disclose the personal, national, and global stories...

  6. Paths of movement

    DEFF Research Database (Denmark)

    Hansen, Lone Koefoed

    2013-01-01

    as narrative material and as a storytelling tool.With her GPS receiver, Polak experiments with ways of access- ing and discussing the many (spatial) narratives that humans, animals, machines, and goods (e.g., dairy products) create in their everyday trajectories. Through an analysis of Polak’s works......As GPS technologies are embedded into mobile devices—and thus everyday life—it has become common to track the location and trajectories of humans as well as objects.While knowing where people and things actually are and have actually been can be interesting, by also engaging with the lives and (hi)stories...

  7. TOOL PATH GENERATION BASED ON STL FILE FOR SHEET METAL DIELESS FORMING

    Institute of Scientific and Technical Information of China (English)

    Liu Jie; Mo Jianhua

    2004-01-01

    Sheet metal dieless forming is a new metal forming technology.This technology adopts the principle of rapid prototyping technology,so it can form sheet metal parts without traditional die and moulds.According to the characteristic of sheet metal dieless forming technology a new way of tool path generation based on the STL file for sheet metal dieless forming is proposed.

  8. Scattering theory with path integrals

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfelder, R. [Particle Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2014-03-15

    Starting from well-known expressions for the T-matrix and its derivative in standard nonrelativistic potential scattering, I rederive recent path-integral formulations due to Efimov and Barbashov et al. Some new relations follow immediately.

  9. Scattering Theory with Path Integrals

    CERN Document Server

    Rosenfelder, R

    2013-01-01

    Starting from well-known expressions for the $T$-matrix and its derivative in standard nonrelativistic potential scattering I rederive recent path-integral formulations due to Efimov and Barbashov et al. Some new relations follow immediately.

  10. The Internet's unexploited path diversity

    CERN Document Server

    Arjona-Villicaña, Pedro David; Stepanenko, Alexander S

    2009-01-01

    The connectivity of the Internet at the Autonomous System level is influenced by the network operator policies implemented. These in turn impose a direction to the announcement of address advertisements and, consequently, to the paths that can be used to reach back such destinations. We propose to use directed graphs to properly represent how destinations propagate through the Internet and the number of arc-disjoint paths to quantify this network's path diversity. Moreover, in order to understand the effects that policies have on the connectivity of the Internet, numerical analyses of the resulting directed graphs were conducted. Results demonstrate that, even after policies have been applied, there is still path diversity which the Border Gateway Protocol cannot currently exploit.

  11. An Introduction to Path Analysis

    Science.gov (United States)

    Wolfe, Lee M.

    1977-01-01

    The analytical procedure of path analysis is described in terms of its use in nonexperimental settings in the social sciences. The description assumes a moderate statistical background on the part of the reader. (JKS)

  12. Equivariant Localization of Path Integrals

    OpenAIRE

    Szabo, Richard J.

    1996-01-01

    We review equivariant localization techniques for the evaluation of Feynman path integrals. We develop systematic geometric methods for studying the semi-classical properties of phase space path integrals for dynamical systems, emphasizing the relations with integrable and topological quantum field theories. Beginning with a detailed review of the relevant mathematical background -- equivariant cohomology and the Duistermaat-Heckman theorem, we demonstrate how the localization ideas are relat...

  13. Path Integrals in Quantum Physics

    OpenAIRE

    2012-01-01

    These lectures aim at giving graduate students an introduction to and a working knowledge of path integral methods in a wide variety of fields in physics. Consequently, the lecture notes are organized in three main parts dealing with non-relativistic quantum mechanics, many-body physics and field theory. In the first part the basic concepts of path integrals are developed in the usual heuristic, non-mathematical way followed by standard examples and special applications including numerical ev...

  14. Formal language constrained path problems

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C.; Jacob, R.; Marathe, M.

    1997-07-08

    In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

  15. RFID-Based Critical Path Expert System for Agility Manufacture Process Management

    Science.gov (United States)

    Cheng, Haifang; Xiang, Yuli

    This paper presents a critical path expert system for the agility manufacture process management based on radio frequency identification (RFID) technology. The paper explores that the agility manufacture processes can be visible and controllable with RFID. The critical paths or activities can be easily found out and tracked by the RFID tracing technology. And the expert system can optimize the bottle neck of the task process of the agility management with the critical path adjusting and reforming method. Finally, the paper gives a simple application example of the system to discuss how to adjust the critical paths and how to make the process more agility and flexibility with the critical path expert system. With an RFID-based critical path expert system, the agility manufacture process management will be more effective and efficient.

  16. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  17. Anomalous paths in quantum mechanical path-integrals

    Energy Technology Data Exchange (ETDEWEB)

    Grimsmo, Arne L., E-mail: arne.grimsmo@ntnu.no [Department of Physics, The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Department of Physics, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Klauder, John R., E-mail: klauder@phys.ufl.edu [Departments of Physics and Mathematics, University of Florida, Gainesville, FL 32611 (United States); Skagerstam, Bo-Sture K., E-mail: bo-sture.skagerstam@ntnu.no [Department of Physics, The Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Kavli Institute for Theoretical Physics, Kohn Hall, University of California at Santa Barbara, CA 93106-4030 (United States); CREOL, The College of Optics and Photonics at the University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816 (United States)

    2013-11-25

    We investigate modifications of the discrete-time lattice action, for a quantum mechanical particle in one spatial dimension, that vanish in the naïve continuum limit but which, nevertheless, induce non-trivial effects due to quantum fluctuations. These effects are seen to modify the geometry of the paths contributing to the path-integral describing the time evolution of the particle, which we investigate through numerical simulations. In particular, we demonstrate the existence of a modified lattice action resulting in paths with any fractal dimension, d{sub f}, between one and two. We argue that d{sub f}=2 is a critical value, and we exhibit a type of lattice modification where the fluctuations in the position of the particle becomes independent of the time step, in which case the paths are interpreted as superdiffusive Lévy flights. We also consider the jaggedness of the paths, and show that this gives an independent classification of lattice theories.

  18. Best Mitigation Paths To Effectively Reduce Earth's Orbital Debris

    Science.gov (United States)

    Wiegman, Bruce M.

    2009-01-01

    This slide presentation reviews some ways to reduce the problem posed by debris in orbit around the Earth. It reviews the orbital debris environment, the near-term needs to minimize the Kessler syndrome, also known as collisional cascading, a survey of active orbital debris mitigation strategies, the best paths to actively remove orbital debris, and technologies that are required for active debris mitigation.

  19. An Application of Calculus: Optimum Parabolic Path Problem

    Science.gov (United States)

    Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali

    2009-01-01

    A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object…

  20. An Application of Calculus: Optimum Parabolic Path Problem

    Science.gov (United States)

    Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali

    2009-01-01

    A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object…

  1. Aircraft path planning for optimal imaging using dynamic cost functions

    Science.gov (United States)

    Christie, Gordon; Chaudhry, Haseeb; Kochersberger, Kevin

    2015-05-01

    Unmanned aircraft development has accelerated with recent technological improvements in sensing and communications, which has resulted in an "applications lag" for how these aircraft can best be utilized. The aircraft are becoming smaller, more maneuverable and have longer endurance to perform sensing and sampling missions, but operating them aggressively to exploit these capabilities has not been a primary focus in unmanned systems development. This paper addresses a means of aerial vehicle path planning to provide a realistic optimal path in acquiring imagery for structure from motion (SfM) reconstructions and performing radiation surveys. This method will allow SfM reconstructions to occur accurately and with minimal flight time so that the reconstructions can be executed efficiently. An assumption is made that we have 3D point cloud data available prior to the flight. A discrete set of scan lines are proposed for the given area that are scored based on visibility of the scene. Our approach finds a time-efficient path and calculates trajectories between scan lines and over obstacles encountered along those scan lines. Aircraft dynamics are incorporated into the path planning algorithm as dynamic cost functions to create optimal imaging paths in minimum time. Simulations of the path planning algorithm are shown for an urban environment. We also present our approach for image-based terrain mapping, which is able to efficiently perform a 3D reconstruction of a large area without the use of GPS data.

  2. Path length enhancement in disordered media for increased absorption.

    Science.gov (United States)

    Mupparapu, Rajeshkumar; Vynck, Kevin; Svensson, Tomas; Burresi, Matteo; Wiersma, Diederik S

    2015-11-30

    We theoretically and numerically investigate the capability of disordered media to enhance the optical path length in dielectric slabs and augment their light absorption efficiency due to scattering. We first perform a series of Monte Carlo simulations of random walks to determine the path length distribution in weakly to strongly (single to multiple) scattering, non-absorbing dielectric slabs under normally incident light and derive analytical expressions for the path length enhancement in these two limits. Quite interestingly, while multiple scattering is expected to produce long optical paths, we find that media containing a vanishingly small amount of scatterers can still provide high path length enhancements due to the very long trajectories sustained by total internal reflection at the slab interfaces. The path length distributions are then used to calculate the light absorption efficiency of media with varying absorption coefficients. We find that maximum absorption enhancement is obtained at an optimal scattering strength, in-between the single-scattering and the diffusive (strong multiple-scattering) regimes. This study can guide experimentalists towards more efficient and potentially low-cost solutions in photovoltaic technologies.

  3. Discrete Coherent State Path Integrals

    Science.gov (United States)

    Marchioro, Thomas L., II

    1990-01-01

    The quantum theory provides a fundamental understanding of the physical world; however, as the number of degrees of freedom rises, the information required to specify quantum wavefunctions grows geometrically. Because basis set expansions mirror this geometric growth, a strict practical limit on quantum mechanics as a numerical tool arises, specifically, three degrees of freedom or fewer. Recent progress has been made utilizing Feynman's Path Integral formalism to bypass this geometric growth and instead calculate time -dependent correlation functions directly. The solution of the Schrodinger equation is converted into a large dimensional (formally infinite) integration, which can then be attacked with Monte Carlo techniques. To date, work in this area has concentrated on developing sophisticated mathematical algorithms for evaluating the highly oscillatory integrands occurring in Feynman Path Integrals. In an alternative approach, this work demonstrates two formulations of quantum dynamics for which the number of mathematical operations does not scale geometrically. Both methods utilize the Coherent State basis of quantum mechanics. First, a localized coherent state basis set expansion and an approximate short time propagator are developed. Iterations of the short time propagator lead to the full quantum dynamics if the coherent state basis is sufficiently dense along the classical phase space path of the system. Second, the coherent state path integral is examined in detail. For a common class of Hamiltonians, H = p^2/2 + V( x) the path integral is reformulated from a phase space-like expression into one depending on (q,dot q). It is demonstrated that this new path integral expression contains localized damping terms which can serve as a statistical weight for Monte Carlo evaluation of the integral--a process which scales approximately linearly with the number of degrees of freedom. Corrections to the traditional coherent state path integral, inspired by a

  4. Redesigning Schools to Reach Every Student with Excellent Teachers: Teacher, Leader, and Paraprofessional Career Paths

    Science.gov (United States)

    Public Impact, 2012

    2012-01-01

    This document provides an overview of multiple career paths that schools can use to expand opportunities for their teachers. These career paths match Public Impact's school models that use job redesign and technology to extend the reach of excellent teachers to more students, for more pay, within budget. Most of these school models create new…

  5. Research on stereo vision path-planning algorithms for mobile robots autonomous navigation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-wei; LU Qiu-hong

    2009-01-01

    Using stereo vision for autonomous mobile robot path-planning is a hot technology. The environment mapping and path-planning algorithms were introduced, and they were applied in the autonomous mobile robot experiment platform. Through experiments in the robot platform, the effectiveness of these algorithms was verified.

  6. New sufficient conditions for Hamiltonian paths.

    Science.gov (United States)

    Rahman, M Sohel; Kaykobad, M; Firoz, Jesun Sahariar

    2014-01-01

    A Hamiltonian path in a graph is a path involving all the vertices of the graph. In this paper, we revisit the famous Hamiltonian path problem and present new sufficient conditions for the existence of a Hamiltonian path in a graph.

  7. Population Monotonic Path Schemes for Simple Games

    NARCIS (Netherlands)

    Ciftci, B.B.; Borm, P.E.M.; Hamers, H.J.M.

    2006-01-01

    A path scheme for a simple game is composed of a path, i.e., a sequence of coalitions that is formed during the coalition formation process and a scheme, i.e., a payoff vector for each coalition in the path.A path scheme is called population monotonic if a player's payoff does not decrease as the pa

  8. Final Rulison Path Forward

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-06-01

    The U.S. Department of Energy (DOE) Office of Legacy Management developed this report as a guide for discussions with the Colorado State regulators and other interested stakeholders in response to increased drilling for natural gas reserves near the underground nuclear explosion site at Rulison, Colorado. The Rulison site is located in the Piceance Basin of western Colorado, 40 miles northeast of Grand Junction. The Rulison test was the second natural gas reservoir stimulation experiment in the Plowshare Program, which was designed to develop peaceful uses for nuclear energy. On September 10, 1969, the U.S. Atomic Energy Commission, a predecessor agency of DOE, detonated a 40-kiloton nuclear device 8426 feet below the ground surface in an attempt to release commercially marketable quantities of natural gas. The blast vaporized surrounding rock and formed a cavity about 150 feet in diameter. Although the contaminated materials from drilling operations were subsequently removed from the surface of the blast site, no feasible technology exists to remove subsurface radioactive contamination in or around the test cavity. An increase in drilling for natural gas near the site has raised concern about the possibility of encountering residual radioactivity from the area of the detonation. DOE prohibits drilling in the 40-acre lot surrounding the blast site at a depth below 6000 feet. DOE has no evidence that indicates contamination from the Rulison site detonation has migrated or will ever migrate beyond the 40-acre institutional control boundary. The Colorado Oil and Gas Conservation Commission (COGCC) established two wider boundaries around the site. When a company applies for a permit to drill within a 3-mile radius of surface ground zero, COGCC notifies DOE and provides an opportunity to comment on the application. COGCC also established a half-mile radius around surface ground zero. An application to drill within one-half mile requires a full hearing before the

  9. Rainbow paths with prescribed ends

    DEFF Research Database (Denmark)

    Alishahi, Meysam; Taherkhani, Ali; Thomassen, Carsten

    2011-01-01

    It was conjectured in [S. Akbari, F. Khaghanpoor, and S. Moazzeni. Colorful paths in vertex coloring of graphs. Preprint] that, if G is a connected graph distinct from C-7, then there is a chi(G)-coloring of G in which every vertex v is an element of V(G) is an initial vertex of a path P with chi......(G) vertices whose colors are different. In[S. Akbari, V. Liaghat, and A. Nikzad. Colorful paths in vertex coloring of graphs. Electron. J. Combin. 18(1):P17, 9pp, 2011] this was proved with left perpendicular chi(G)/2right perpendicular vertices instead of chi(G) vertices. We strengthen this to chi(G) - 1...

  10. Path Decomposition of Graphs with Given Path Length

    Institute of Scientific and Technical Information of China (English)

    Ming-qing Zhai; Chang-hong Lü

    2006-01-01

    A path decomposition of a graph G is a list of paths such that each edge appears in exactly one path in the list. G is said to admit a {Pl}-decomposition if G can be decomposed into some copies of Pl, where Pl is a path of length ι - 1. Similarly, G is said to admit a {Pl, Pκ}-decomposition if G can be decomposed into some copies of Pl or Pκ. An κ-cycle, denoted by Cκ, is a cycle with κ vertices. An odd tree is a tree of which all vertices have odd degree. In this paper, it is shown that a connected graph G admits a {P3, P4}-decomposition if and only if G is neither a 3-cycle nor an odd tree. This result includes the related result of Yan, Xu and Mutu. Moreover, two polynomial algorithms are given to find {P3}-decomposition and {P3, P4}-decomposition of graphs, respectively. Hence, {P3}-decomposition problem and {P3, P4}-decomposition problem of graphs are solved completely.

  11. Spin Observables and Path Integrals

    CERN Document Server

    López, J A

    2000-01-01

    We discuss the formulation of spin observables associated to a non-relativistic spinning particles in terms of grassmanian differential operators. We use as configuration space variables for the pseudo-classical description of this system the positions $x$ and a Grassmanian vector quantum amplitudes as path integrals in this superspace. We compute the quantum action necessary for this description including an explicit expression for the boundary terms. Finally we shown how for simple examples, the path integral may be performed in the semi-classical approximation, leading to the correct quantum propagator.

  12. Paths of algebraic hyperbolic curves

    Institute of Scientific and Technical Information of China (English)

    Ya-juan LI; Li-zheng LU; Guo-zhao WANG

    2008-01-01

    Cubic algebraic hyperbolic (AH) Bezier curves and AH spline curves are defined with a positive parameter α in the space spanned by {1, t, sinht, cosht}. Modifying the value of α yields a family of AH Bezier or spline curves with the family parameter α. For a fixed point on the original curve, it will move on a defined curve called "path of AH curve" (AH Bezier and AH spline curves) when α changes. We describe the geometric effects of the paths and give a method to specify a curve passing through a given point.

  13. Strings, paths, and standard tableaux

    CERN Document Server

    Dasmahapatra, S

    1996-01-01

    For the vacuum sectors of regime-III ABF models, we observe that two sets of combinatorial objects: the strings which parametrize the row-to-row transfer matrix eigenvectors, and the paths which parametrize the corner transfer matrix eigenvectors, can both be expressed in terms of the same set of standard tableaux. Furthermore, the momenta of the strings, the energies of the paths, and the charges of the tableaux are such that there is a weight-preserving bijection between the two sets of eigenvectors, wherein the tableaux play an interpolating role. This bijection is so natural, that we conjecture that it exists in general.

  14. Fundamental changes to EPA's research enterprise: the path forward.

    Science.gov (United States)

    Anastas, Paul T

    2012-01-17

    Environmental protection in the United States has reached a critical juncture. It has become clear that to address the complex and interrelated environmental challenges we face, we must augment our traditional approaches. The scientific community must build upon its deep understanding of risk assessment, risk management, and reductionism with tools, technologies, insights and approaches to pursue sustainability. The U.S. Environmental Protection Agency (EPA) has recognized this need for systemic change by implementing a new research paradigm called "The Path Forward." This paper outlines the principles of the Path Forward and the actions taken since 2010 to align EPA's research efforts with the goal of sustainability.

  15. 关于强化FDI技术溢出效应的路径选择的思考%Thoughts on Path Selection for Enhancing FDI Technology Spillover Effects

    Institute of Scientific and Technical Information of China (English)

    郭雪超

    2012-01-01

    多年来,我国作为最大的发展中国家已成为FDI的首选,一直位居全球发展中国家首位。当前,影响FDI技术溢出效应的因素是跨国公司的技术控制、东道国的市场环境、技术差距、东道国的人力资本水平和吸收能力。强化FDI技术溢出效应,应引入竞争机制,营造有效的市场竞争环境;重视人力资本投入。进一步发展教育和培训体系;重视科学研究,强化产、学、研之间的资源联动;鼓励跨国公司与国内企业、院校、科研机构的技术合作,加速其技术溢出。%In recent years, as the biggest developing country, China has become the prime choice of FDI, ranking first among developing countries in the world. Factors influencing FDI technology spillover effects include the technology control from multinational companies, market environment of host countries, teehndogical gap, and human capital level and absorption capacity of host countries. To strengthen FDI technology spillover effects, we need to introduce competitive mechanism, creating powerful competitive market environment; attach importance to the investment of human capital to further develop the education and training system; focus on scientific research, enhancing the resource linkage between production, learning and research; and encourage the technology cooperation between multinational compa- nies, domestic companies, academies and research institutions to speed up the technology Spillover.

  16. Enlightenments from the Path Analysis on the Science & Technology Innovation Management of Governments in East Asia%东亚地区政府科技创新管理的路径分析及启示

    Institute of Scientific and Technical Information of China (English)

    张毅强; 吴大器

    2014-01-01

    科技创新管理是将一般管理学和公共管理学的原理、方法、手段运用于科学技术管理的具体实践。东亚地区的日本、韩国、台湾和香港在经济发展过程中,政府始终保持在科技创新管理过程中的强势主导地位,坚持科技创新战略与经济产业政策的强相关性,以行政手段积极推动官、产、学、研协同创新,科技决策和管理部门的政治地位日渐增强。目前,上述东亚地区政府的科技战略规划转向社会民生领域,逐渐弱化科技创新管理的行政集权倾向,引入现代服务业推动科技成果转化,并通过健全和完善科技金融体系,支持和培育科技创新。总体而言,上述东亚地区政府的科技创新管理体制已趋于完善,对我国实施创新驱动发展战略具有重要的借鉴价值。%The science & technology innovation management is the practice of applying theories , methods , and measures of general management and public management to the science & technology management . During the course of economic development , governments of Japan , Korea , Taiwan and Hong Kong in East Asia have been always holding their leading role in the science & technology innovation management , upholding the strong correlation between national scientific innovation strategy and industrial policies , promoting the industry-university-research collaborative innovation by administrative measures , and enhancing the political status of departments of science & technology decision-making and management . At present , their science & technology strategy and planning of these governments mentioned above are turning around to the social and livelihood field , gradually weakening the administrative centralization in the science & technology innovation management , introducing modern service industry to advance the transformation of scientific and technical results , and supporting and nurturing science & technology

  17. Manufacturing technology

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, J.A.; Floyd, H.L.; Goetsch, B.; Doran, L. [eds.

    1993-08-01

    This bulletin depicts current research on manufacturing technology at Sandia laboratories. An automated, adaptive process removes grit overspray from jet engine turbine blades. Advanced electronic ceramics are chemically prepared from solution for use in high- voltage varistors. Selective laser sintering automates wax casting pattern fabrication. Numerical modeling improves performance of photoresist stripper (simulation on Cray supercomputer reveals path to uniform plasma). And mathematical models help make dream of low- cost ceramic composites come true.

  18. On the path to differentiation

    DEFF Research Database (Denmark)

    Martinsen, Dorte Sindbjerg; Uygur, Ayca

    2014-01-01

    by examining the ‘path to differentiation’ within EU working time regulation as it has unfolded over time. It identifies the ‘opt-out’ as a means of differentiation adopted to overcome policy deadlocks within collective decision-making, albeit one with unforeseen consequences. In particular, the contribution...

  19. Career Paths in Environmental Sciences

    Science.gov (United States)

    Career paths, current and future, in the environmental sciences will be discussed, based on experiences and observations during the author's 40 + years in the field. An emphasis will be placed on the need for integrated, transdisciplinary systems thinking approaches toward achie...

  20. Geodesic flows on path spaces

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the path space over a compact Riemannian manifold, the global existence and the global uniqueness of the quasi-invariant geodesic flows with respect to a negative Markov connection are obtained in this paper. The results answer affirmatively a left problem of Li.

  1. Path integral for inflationary perturbations

    NARCIS (Netherlands)

    Prokopec, T.; Rigopoulos, G.

    2010-01-01

    The quantum theory of cosmological perturbations in single-field inflation is formulated in terms of a path integral. Starting from a canonical formulation, we show how the free propagators can be obtained from the well-known gauge-invariant quadratic action for scalar and tensor perturbations, and

  2. Methodologies for tracking learning paths

    DEFF Research Database (Denmark)

    Frølunde, Lisbeth; Gilje, Øystein; Lindstrand, Fredrik

    2009-01-01

    The article concerns the design of a collaborative research project (2008-09) entitled Making a Filmmaker, which examines how young Scandinavian filmmakers create their own learn- ing paths in formal and/or informal contexts. Our interest is how learning experiences and contexts motivate the young...

  3. Determinants of weighted path matrices

    CERN Document Server

    Talaska, Kelli

    2012-01-01

    We find rational expressions for all minors of the weighted path matrix of a directed graph, generalizing the classical Lindstrom/Gessel-Viennot result for acyclic directed graphs. The formulas are given in terms of certain flows in the graph.

  4. 提升东北亚城市科技创新能力的因素探讨——基于结构化方程模型的路径分析%Factor Analysis on Enhancing Scientific and Technological Innovation in Northeast Asia——Based on structural equation model of path analysis

    Institute of Scientific and Technical Information of China (English)

    郑琼洁; 倪鹏飞; 杨旭

    2011-01-01

    This article selects 2009-2010 annual data,and constructs the index system of technology innovation in Northeast Asia,based on cluster analysis and discriminant analysis,we divide the 155 cities of Northeast Asia into four categories, then through structural equation, we discuss the factors including governance, cultural and economic environment which affect technology innovation and probe the conduction path between government management, economic environment and cultural environment. The result shows that the economic environment is the direct impact of the most important factor in technological innovation (0. 666) ,and the existence of scientific and technological innovation has direct and indirect role in the path; government management effects innovation though both economic and cultural environment relatively, the cultural environment has weakest impact on innovation,reveals only 0. 07. Finally,we give some policy recommendations.%选取2009-2010年东北亚155个城市作为研究样本,构造了东北亚城市科技创新能力评估指标体系;基于聚类分析、判别分析方法,将东北亚155个城市划分为四大类,在此基础上,通过结构化方程模型(SEM),对影响东北亚城市科技创新能力的政府管理、文化环境和经济环境三大要素进行了探讨,并对路径传导及要素间的相互作用进行了研究,最后提出了计算科技创新能力的两种方法.研究结果显示,经济环境是影响科技创新能力最主要的直接因素(0.666),并且对科技创新能力存在直接和间接两条作用路径,而政府管理通过经济环境和文化环境的间接传导来影响科技创新能力;相对而言,文化环境对科技创新能力的影响较弱,仅为0.07.最后,提出了几点政策建议.

  5. Optimal paths as correlated random walks

    Science.gov (United States)

    Perlsman, E.; Havlin, S.

    2006-01-01

    A numerical study of optimal paths in the directed polymer model shows that the paths are similar to correlated random walks. It is shown that when a directed optimal path of length t is divided into 3 segments whose length is t/3, the correlation between the transversal movements along the first and last path segments is independent of the path length t. It is also shown that the transversal correlations along optimal paths decrease as the paths approach their endpoints. The numerical results obtained for optimal paths in 1+4 dimensions are qualitatively similar to those obtained for optimal paths in lower dimensions, and the data supplies a strong numerical indication that 1+4 is not the upper critical dimension of this model, and of the associated KPZ equation.

  6. Implementing Operating System Support for Extended Trusted Path in TPM-Capable Environments

    Institute of Scientific and Technical Information of China (English)

    SHI Wenchang

    2006-01-01

    Trusted path is one of the crucial features that operating systems must provide for fundamental security support. In order to explore the possibility of implementing a trusted path mechanism with the support of trusted platform module (TPM) technologies, and to support TPM capabilities in operating systems, the paper extended the scope of the conventional trusted path to cover the situation in which a user communicates with software residing on a remote host. The paper combined the concept of operating system support for trusted path with that for TPM platforms, and proposed the architecture of an extended trusted path mechanism in operating system with considerations on TPM-capable platforms support. As part of the author' research in secure operating systems, the work of the paper was carried out with Linux as an experimental prototype system. The research result shows that TPM capabilities can strengthen extended trusted path mechanisms of operating systems.

  7. NGNP Program 2013 Status and Path Forward

    Energy Technology Data Exchange (ETDEWEB)

    Hans Gougar

    2014-03-01

    High temperature gas-cooled reactor (HTGR) technology can play an important role in the energy future of the United States by extending the use of nuclear energy for non-electricity energy production missions, as well as continuing to provide a considerable base load electric power generation capability. Extending nuclear energy into the industrial and transportation sectors through the coproduction of process heat and electricity provides safe, reliable energy for these sectors in an environmentally responsible manner. The modular HTGR provides a substantial improvement in nuclear plant safety for the protection of the public and the environment, and supports collocation of the HTGRhigh temperature gas-cooled reactor with major industrial facilities. Under U.S. Department of Energy direction since 2006, the Next Generation Nuclear Plant Project at Idaho National Laboratory has been working toward commercializing the HTGR technology. However, a recent decision by the Secretary of Energy to reduce the scope of the Next Generation Nuclear Plant Project to a research and development program, considerable realignment has taken place. This report: (1) summarizes the accomplishments of the Next Generation Nuclear Plant Program from FY2011 through FY2013; (2) lays out the path forward necessary to achieve the ultimate objective of commercializing HTGR technology; and (3) discusses ongoing technical, licensing, and evaluation activities under the realigned Next Generation Nuclear Plant program considered important to preserve the significant investment made by the government to-date and to maintain some progress in meeting the objectives of the Energy Policy Act of 2005 (EPAct2005).

  8. Promoting Renewable Energy Technologies

    DEFF Research Database (Denmark)

    Olsen, Ole Jess; Skytte, Klaus

    % of its annual electricity production. In this paper, we present and discuss the Danish experience as a case of promoting renewable energy technologies. The development path of the two technologies has been very different. Wind power is considered an outright success with fast deployment to decreasing...... technology and its particular context, it is possible to formulate some general principles that can help to create an effective and efficient policy for promoting new renewable energy technologies....

  9. Promoting Renewable Energy Technologies

    DEFF Research Database (Denmark)

    Olsen, Ole Jess; Skytte, Klaus

    % of its annual electricity production. In this paper, we present and discuss the Danish experience as a case of promoting renewable energy technologies. The development path of the two technologies has been very different. Wind power is considered an outright success with fast deployment to decreasing...... technology and its particular context, it is possible to formulate some general principles that can help to create an effective and efficient policy for promoting new renewable energy technologies....

  10. Calculating Least Risk Paths in 3d Indoor Space

    Science.gov (United States)

    Vanclooster, A.; De Maeyer, Ph.; Fack, V.; Van de Weghe, N.

    2013-08-01

    Over the last couple of years, research on indoor environments has gained a fresh impetus; more specifically applications that support navigation and wayfinding have become one of the booming industries. Indoor navigation research currently covers the technological aspect of indoor positioning and the modelling of indoor space. The algorithmic development to support navigation has so far been left mostly untouched, as most applications mainly rely on adapting Dijkstra's shortest path algorithm to an indoor network. However, alternative algorithms for outdoor navigation have been proposed adding a more cognitive notion to the calculated paths and as such adhering to the natural wayfinding behaviour (e.g. simplest paths, least risk paths). These algorithms are currently restricted to outdoor applications. The need for indoor cognitive algorithms is highlighted by a more challenged navigation and orientation due to the specific indoor structure (e.g. fragmentation, less visibility, confined areas…). As such, the clarity and easiness of route instructions is of paramount importance when distributing indoor routes. A shortest or fastest path indoors not necessarily aligns with the cognitive mapping of the building. Therefore, the aim of this research is to extend those richer cognitive algorithms to three-dimensional indoor environments. More specifically for this paper, we will focus on the application of the least risk path algorithm of Grum (2005) to an indoor space. The algorithm as proposed by Grum (2005) is duplicated and tested in a complex multi-storey building. The results of several least risk path calculations are compared to the shortest paths in indoor environments in terms of total length, improvement in route description complexity and number of turns. Several scenarios are tested in this comparison: paths covering a single floor, paths crossing several building wings and/or floors. Adjustments to the algorithm are proposed to be more aligned to the

  11. Mobile Robot Path Planning by RRT* in Dynamic Environments

    Directory of Open Access Journals (Sweden)

    Roudabe Seif

    2015-05-01

    Full Text Available Robot navigation is challenging for mobile robots technology in environments with maps. Since finding an optimal path for the agent is complicated and time consuming, path planning in robot navigation is an axial issue. The objective of this paper is to find a reasonable relation between parameters used in the path planning algorithm in a platform which a robot will be able to move from the start point in a dynamic environment with map and plan an optimal path to specified goal without any collision with moving and static obstacles. For this purpose, an asymptotically optimal version of Rapidly-exploring Random Tree RRT algorithm, named RRT* is used. The algorithm is based on an incremental sampling which covers the whole space and acts fast. Moreover this algorithm is computationally efficient, therefore it can be used in multidimensional environments. The obtained results indicate that a feasible path for mobile holomonic robot may be found in a short time by using this algorithm. Also different standard distances measurements like (Chebyshev, Euclidean, and City Block are examined, and coordinated with sampling node number in order to reach the suitable result based on environment circumstances.

  12. ACO in e-Learning: Towards an adaptive learning path

    Directory of Open Access Journals (Sweden)

    Pushpa. M

    2012-03-01

    Full Text Available Today we are in an era where drastic advancements in networking and information technology are in action. The learning process has also taken these advancements, as a result of which e-learning came to thescene. Personalization in e-learning will improve the performance of the system. Recent researches are concentrating on providing adaptability to the learning management systems, depending upon the varying user needs and contexts. Adaptability can be provided at different levels .Providing an adaptive learning path according to the context of the learners’ is an important issue. An optimal adaptive learning path will help the learners in reducing the cognitive overload and disorientation, and thereby improving the efficiency of the Learning Management System (LMS. Ant Colony Optimization (ACO is a widely accepted technique since it provides an adaptive learning path to the learners. Meta-heuristic which is used in intelligent tutoring systems provides the learning path in an adaptive way. The most interesting feature of ACO is its adaptation and robustness in an environment where the learning materials and learners are changing frequently. In this paper we can have a look through the existing ACO approaches towards providing an adaptive learning path and an introduction towards an enhanced attribute ant for making the e-learning system more adaptive.

  13. Benchmarking Gas Path Diagnostic Methods: A Public Approach

    Science.gov (United States)

    Simon, Donald L.; Bird, Jeff; Davison, Craig; Volponi, Al; Iverson, R. Eugene

    2008-01-01

    Recent technology reviews have identified the need for objective assessments of engine health management (EHM) technology. The need is two-fold: technology developers require relevant data and problems to design and validate new algorithms and techniques while engine system integrators and operators need practical tools to direct development and then evaluate the effectiveness of proposed solutions. This paper presents a publicly available gas path diagnostic benchmark problem that has been developed by the Propulsion and Power Systems Panel of The Technical Cooperation Program (TTCP) to help address these needs. The problem is coded in MATLAB (The MathWorks, Inc.) and coupled with a non-linear turbofan engine simulation to produce "snap-shot" measurements, with relevant noise levels, as if collected from a fleet of engines over their lifetime of use. Each engine within the fleet will experience unique operating and deterioration profiles, and may encounter randomly occurring relevant gas path faults including sensor, actuator and component faults. The challenge to the EHM community is to develop gas path diagnostic algorithms to reliably perform fault detection and isolation. An example solution to the benchmark problem is provided along with associated evaluation metrics. A plan is presented to disseminate this benchmark problem to the engine health management technical community and invite technology solutions.

  14. Facilitating Description and Selection of Learning Paths: the learning path specification put to the test

    NARCIS (Netherlands)

    Janssen, José

    2008-01-01

    Jansen, J. (2008). Facilitating Description and Selection of Learning Paths: the learning path specification put to the test. Presentation at the Otec Colloquium. April, 2008, Heerlen, The Netherlands.

  15. Facilitating Description and Selection of Learning Paths: the learning path specification put to the test

    NARCIS (Netherlands)

    Janssen, José

    2008-01-01

    Jansen, J. (2008). Facilitating Description and Selection of Learning Paths: the learning path specification put to the test. Presentation at the Otec Colloquium. April, 2008, Heerlen, The Netherlands.

  16. Analysis the new path of the popularizing appropriate health technology of Tradtional Chinese Medcine in rural areas%中医适宜技术在农村基层实施的新路径探析

    Institute of Scientific and Technical Information of China (English)

    胡凌娟; 房耘耘; 满晓玮; 周宇琼

    2011-01-01

    本文通过部分省市调研结果,分析了目前中医适宜技术在基层推广的一些问题,提出应根据推广地区的实际需求和经济发展水平,扩大推广途径,除了依托各级各类公立医疗机构外,应选择适合农村基层地区的中医适宜技术防治项目,通过扩充具备条件的村卫生室、个体中医诊所等进行推广,从而促进项目的更好开展.%To analyze the influencing factors of popularizing appropriate health technology (AHT) of Tradtional Chinese Medcine in rural areas. Health service providers should he not only all different levels of public medical institutes, but also includes clinics and clinics sanitation rooms in rural areas. It can strengthen popularizing appropriate health technology (AHT).

  17. 中小企业技术创新的路径--基于知识管理理论%A Research into the Path of Technological Innovation in SMEs on the Basis of the Theory of Knowledge Management

    Institute of Scientific and Technical Information of China (English)

    李建中

    2014-01-01

    中小企业作为国民经济中最活跃的部门之一,面临着巨大的生存考验,中小企业的“知识化”是其不二的选择。中小企业要生存、发展和壮大,技术创新是必由之路。通过分析成功实现快速发展壮大的企业的成长经验,发现知识的积累、发酵与扩散是中小企业获得技术创新的内在驱动力,这为中小企业提供了可借鉴的技术创新路径。%The small and medium-sized enterprises (SMEs) are one of the most active sectors in economic activ-ities, with the stress of their survival, SMEs have to be knowledgeable. For their survival, developing and growing, SMEs' technology innovation is very important. Through the analysis of the successful fast developed enterprise, it is found that the knowledge's accumulation, fermentation and diffusion are the internal driving force of SMEs' techno-logical innovation, which provides reference for other SMEs.

  18. 从权力控制到政治吸纳:科技防腐的演变路径%From Power Control to Political Absorption:the Evolution Path of the Anti-corruption by Technology

    Institute of Scientific and Technical Information of China (English)

    卜万红

    2014-01-01

    现代科学技术在防治腐败的过程中表现出越来越明显的优势,它有助于控制权力、削弱腐败动机,减少腐败机会。以“制度+科技”为主要特征的科技防腐模式是中国将现代科学技术融入惩治和预防腐败体系建设的产物,它以较低的成本实现了对权力的制约和监督,最大限度地降低了委托代理关系中由于信息不对称和机会主义等因素造成的交易成本。科技防腐是一个交易成本最优化的反腐形式,是建设廉洁政治的有利工具。随着现代科学技术与社会主义民主政治建设的深度融合,网络政治的兴起与发展是必然趋势,它以相对低廉的成本直接影响并作用于最深层次的权力结构,推动科技防腐从以体制内权力控制和体制外权力监督为主要特征的传统双向发展模式向以体制内权力控制和体制外政治吸纳为主要特征的新双向发展模式转变,从而实现从源头上防治腐败。%Modern science and technology has demonstrated increasing advantage in the prevention and control of cor -ruption.It is conducive to power control , weakening of corrupt ion motivation and reduction in corruption opportuni -ties.Taking “system +technology” as the main characteristics , the corruption prevention model is the product of putting the modern technology into the system construction of punishing and preventing corruption .It realizes the re-striction and supervision of power at a lower cost , minimizes the transaction costs in the principal-agent relationship caused by factors such as asymmetric information and opportunism .As a transaction cost optimization form of corrup-tion prevention , anti-corruption by technology is a useful tool for the construction of clean politics .With modern sci-ence and technology integrated into the construction of socialist democratic politics , the rise and development of net-work politics has become an inevitable trend

  19. Shortest Paths With Side Sensors

    CERN Document Server

    Salaris, Paolo; Bicchi, Antonio

    2011-01-01

    We present a complete characterization of shortest paths to a goal position for a vehicle with unicycle kinematics and a limited range sensor, constantly keeping a given landmark in sight. Previous work on this subject studied the optimal paths in case of a frontal, symmetrically limited Field--Of--View (FOV). In this paper we provide a generalization to the case of arbitrary FOVs, including the case that the direction of motion is not an axis of symmetry for the FOV, and even that it is not contained in the FOV. The provided solution is of particular relevance to applications using side-scanning, such as e.g. in underwater sonar-based surveying and navigation.

  20. Stochastic control with rough paths

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Joscha [University of California San Diego (United States); Friz, Peter K., E-mail: friz@math.tu-berlin.de [TU & WIAS Berlin (Germany); Gassiat, Paul [CEREMADE, Université Paris-Dauphine, PSL Research University (France)

    2017-04-15

    We study a class of controlled differential equations driven by rough paths (or rough path realizations of Brownian motion) in the sense of Lyons. It is shown that the value function satisfies a HJB type equation; we also establish a form of the Pontryagin maximum principle. Deterministic problems of this type arise in the duality theory for controlled diffusion processes and typically involve anticipating stochastic analysis. We make the link to old work of Davis and Burstein (Stoch Stoch Rep 40:203–256, 1992) and then prove a continuous-time generalization of Roger’s duality formula [SIAM J Control Optim 46:1116–1132, 2007]. The generic case of controlled volatility is seen to give trivial duality bounds, and explains the focus in Burstein–Davis’ (and this) work on controlled drift. Our study of controlled rough differential equations also relates to work of Mazliak and Nourdin (Stoch Dyn 08:23, 2008).

  1. Study on the Evolutionary Path of Technological Capability and the Choice of Niche Market: A Case on MY Corporation%技术能力演化路径与利基市场选择:MY公司的案例研究

    Institute of Scientific and Technical Information of China (English)

    陈德富; 在义飞; 倪得兵; 李仕明

    2011-01-01

    This paper is based on a typical case company with 50 years of history. It carefully examines the dynamic relationship between the evolutionary path of technological capability and the choice of niche market in the company through interviews, field study, history and archive study. We divide the history of the company into three stages and came to four theoretical conclusions as follows: (1) in the initial stage of the company (or the early stage of a new market entry) , a successful niche firm chooses to enter an industrial section with low competition and high profitability through differentiation by the exploiting its capability of imitation; (2) in the growing stage of the company, the niche firm's technological capability is improved due to technology diffusion, the firm tends to enter diversified niche markets. (3)in this stage, proper entering diversified market is positively related to the improvement of the firm's technological capability, however, over-entering diversified market is negatively related to the improvement of the firm's technological capability. (4) in the mature stage of the company, niche firm acquires core technological capability via complementary asset and indigenous innovation and focuses on core niche market. Based on the aforementioned conclusions, we formulate a comprehensive dynamic evolving model between firm's evolutionary path of technological capability and the choice of niche market.%选取一个具有50年发展历史的典型案例开展研究,通过访谈、实地研究、历史与档案数据等研究方法以及3个历史阶段的划分,考察了技术能力与利基市场之间的动态演化关系.根据利基企业在不同阶段的研究,得到了4个结论:①在创业初期(或进入新市场),成功的利基企业选择利用仿制能力,通过差异化进入低竞争和高盈利的产业环节;②进入成长期,利基企业技术能力通过扩散提升,倾向于进入多利基市场;③适度进入多元化

  2. Levy Flights over Quantum Paths

    CERN Document Server

    Laskin, N

    2005-01-01

    An impact of integration over the paths of the Levy flights on the quantum mechanical kernel has been studied. Analytical expression for a free particle kernel has been obtained in terms of the Fox H-function. A new equation for the kernel of a partical in the box has been found. New general results include the well known quantum formulae for a free particle kernel and particle in box kernel.

  3. The path of code linting

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Join the path of code linting and discover how it can help you reach higher levels of programming enlightenment. Today we will cover how to embrace code linters to offload cognitive strain on preserving style standards in your code base as well as avoiding error-prone constructs. Additionally, I will show you the journey ahead for integrating several code linters in the programming tools your already use with very little effort.

  4. AFM's path to atomic resolution

    OpenAIRE

    2005-01-01

    We review progress in improving the spatial resolution of atomic force microscopy (AFM) under vacuum. After an introduction to the basic imaging principle and a conceptual comparison to scanning tunneling microscopy (STM), we outline the main challenges of AFM as well as the solutions that have evolved in the first 20 years of its existence. Some crucial steps along AFM's path toward higher resolution are discussed, followed by an outlook on current and future applications.

  5. Path planning under spatial uncertainty.

    Science.gov (United States)

    Wiener, Jan M; Lafon, Matthieu; Berthoz, Alain

    2008-04-01

    In this article, we present experiments studying path planning under spatial uncertainties. In the main experiment, the participants' task was to navigate the shortest possible path to find an object hidden in one of four places and to bring it to the final destination. The probability of finding the object (probability matrix) was different for each of the four places and varied between conditions. Givensuch uncertainties about the object's location, planning a single path is not sufficient. Participants had to generate multiple consecutive plans (metaplans)--for example: If the object is found in A, proceed to the destination; if the object is not found, proceed to B; and so on. The optimal solution depends on the specific probability matrix. In each condition, participants learned a different probability matrix and were then asked to report the optimal metaplan. Results demonstrate effective integration of the probabilistic information about the object's location during planning. We present a hierarchical planning scheme that could account for participants' behavior, as well as for systematic errors and differences between conditions.

  6. Spreading paths in partially observed social networks

    CERN Document Server

    Onnela, Jukka-Pekka

    2011-01-01

    Understanding how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading path lengths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, structurally realistic social network as a platform for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Alt...

  7. Time optimal paths for high speed maneuvering

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  8. Path-based Queries on Trajectory Data

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Pelekis, Nikos; Theodoridis, Yannis

    2014-01-01

    a specific path by only retrieving data from the first and last edge in the path. To correctly answer strict path queries existing network-constrained trajectory indexes must retrieve data from all edges in the path. An extensive performance study of NETTRA using a very large real-world trajectory data set....... To efficiently support strict path queries, we present a novel NETwork-constrained TRAjectory index (NETTRA). This index enables very efficient retrieval of trajectories that follow a specific path, i.e., strict path queries. NETTRA uses a new path encoding scheme that can determine if a trajectory follows......, consisting of 1.7 million trajectories (941 million GPS records) and a road network with 1.3 million edges, shows a speed-up of two orders of magnitude compared to state-of-the-art trajectory indexes....

  9. Multiresolution Path Planning for Mobile Robots,

    Science.gov (United States)

    1985-05-01

    8217U’ MULTIRESOLUTION PATH PLANNING * . FOR MOBILE ROBOTS I Subbarao Kambhampati * -- Larry S. Davis Computer Vision Laboratory * Center for Automation...COUWEPARK MARVUM EP Vo Is- .. . .. CAR-TR-127 DAAK70-83-K--0018 CS-TR-1507 MAY 1085 MULTIRESOLUTION PATH PLANNING FOR MOBILE ROBOTS Subbarao Kambhampati...planning is central to mobile * robot applications. Path planning for mobile robots is in many ways different * from the more familiar case of path

  10. Multiple Paths to Encephalization and Technical Civilizations

    Science.gov (United States)

    Schwartzman, David; Middendorf, George

    2011-12-01

    We propose consideration of at least two possible evolutionary paths for the emergence of intelligent life with the potential for technical civilization. The first is the path via encephalization of homeothermic animals; the second is the path to swarm intelligence of so-called superorganisms, in particular the social insects. The path to each appears to be facilitated by environmental change: homeothermic animals by decreased climatic temperature and for swarm intelligence by increased oxygen levels.

  11. Path-Based Supports for Hypergraphs

    Science.gov (United States)

    Brandes, Ulrik; Cornelsen, Sabine; Pampel, Barbara; Sallaberry, Arnaud

    A path-based support of a hypergraph H is a graph with the same vertex set as H in which each hyperedge induces a Hamiltonian subgraph. While it is NP-complete to compute a path-based support with the minimum number of edges or to decide whether there is a planar path-based support, we show that a path-based tree support can be computed in polynomial time if it exists.

  12. Aircraft Engine Gas Path Diagnostic Methods: Public Benchmarking Results

    Science.gov (United States)

    Simon, Donald L.; Borguet, Sebastien; Leonard, Olivier; Zhang, Xiaodong (Frank)

    2013-01-01

    Recent technology reviews have identified the need for objective assessments of aircraft engine health management (EHM) technologies. To help address this issue, a gas path diagnostic benchmark problem has been created and made publicly available. This software tool, referred to as the Propulsion Diagnostic Method Evaluation Strategy (ProDiMES), has been constructed based on feedback provided by the aircraft EHM community. It provides a standard benchmark problem enabling users to develop, evaluate and compare diagnostic methods. This paper will present an overview of ProDiMES along with a description of four gas path diagnostic methods developed and applied to the problem. These methods, which include analytical and empirical diagnostic techniques, will be described and associated blind-test-case metric results will be presented and compared. Lessons learned along with recommendations for improving the public benchmarking processes will also be presented and discussed.

  13. Ant Colony Based Path Planning Algorithm for Autonomous Robotic Vehicles

    Directory of Open Access Journals (Sweden)

    Yogita Gigras

    2012-11-01

    Full Text Available The requirement of an autonomous robotic vehicles demand highly efficient algorithm as well as software. Today’s advanced computer hardware technology does not provide these types of extensive processing capabilities, so there is still a major space and time limitation for the technologies that are available for autonomous robotic applications. Now days, small to miniature mobile robots are required for investigation, surveillance and hazardous material detection for military and industrial applications. But these small sized robots have limited power capacity as well as memory and processing resources. A number of algorithms exist for producing optimal path for dynamically cost. This paper presents a new ant colony based approach which is helpful in solving path planning problem for autonomous robotic application. The experiment of simulation verified its validity of algorithm in terms of time.

  14. Partial Path Column Generation for the ESPPRC

    DEFF Research Database (Denmark)

    Jepsen, Mads Kehlet; Petersen, Bjørn

    This talk introduces a decomposition of the Elementary Shortest Path Problem with Resource Constraints(ESPPRC), where the path is combined by smaller sub paths. We show computational result by comparing different approaches for the decomposition and compare the best of these with existing...

  15. Multi-level Indoor Path Planning Method

    NARCIS (Netherlands)

    Xiong, Q.; Zhu, Q.; Zlatanova, S.; Du, Z.; Zhang, Y.; Zeng, L.

    2015-01-01

    Indoor navigation is increasingly widespread in complex indoor environments, and indoor path planning is the most important part of indoor navigation. Path planning generally refers to finding the most suitable path connecting two locations, while avoiding collision with obstacles. However, it is a

  16. A SCALED CENTRAL PATH FOR LINEAR PROGRAMMING

    Institute of Scientific and Technical Information of China (English)

    Ya-xiang Yuan

    2001-01-01

    Interior point methods are very efficient methods for solving large scale linear programming problems. The central path plays a very important role in interior point methods. In this paper we propose a new central path, which scales the variables. Thus it has the advantage of forcing the path to have roughly the same distance from each active constraint boundary near the solution.

  17. Symbolic PathFinder v7

    DEFF Research Database (Denmark)

    Luckow, Kasper Søe; Păsăreanu, Corina

    2014-01-01

    We describe Symbolic PathFinder v7 in terms of its updated design addressing the changes of Java PathFinder v7 and of its new optimization when computing path conditions. Furthermore, we describe the Symbolic Execution Tree Extension; a newly added feature that allows for outputting the symbolic ...

  18. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2016-01-01

    Graduate students who want to become familiar with advanced computational strategies in classical and quantum dynamics will find here both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name a few. Well-chosen and detailed examples illustrate the perturbation theory, canonical transformations, the action principle and demonstrate the usage of path integrals. This new edition has been revised and enlarged with chapters on quantum electrodynamics, high energy physics, Green’s functions and strong interaction.

  19. A path to integration in an academic health science center.

    Science.gov (United States)

    Panko, W B; Wilson, W

    1992-01-01

    This article describes a networking and integration strategy in use at the University of Michigan Medical Center. This strategy builds upon the existing technology base and is designed to provide a roadmap that will direct short-term development along a productive, long-term path. It offers a way to permit the short-term development of incremental solutions to current problems while at the same time maximizing the likelihood that these incremental efforts can be recycled into a more comprehensive approach.

  20. The critical path initiative: leveraging collaborations to enhance regulatory science.

    Science.gov (United States)

    Barratt, R A; Bowens, S L; McCune, S K; Johannessen, J N; Buckman, S Y

    2012-03-01

    Since 2004, the Critical Path Initiative has prompted industry, academia, and government agencies to work together to share the information, technology, and expertise critical to modernize and transform our approach to drug development and review. Various collaborations have been sharing data in a precompetitive space, establishing data standards, and facilitating collective tool development. As a result, the organization is making progress toward developing knowledge and tools that can reduce uncertainty in medical product development.

  1. Bench Testing Results for the Electrical PCM-Assisted Thermal Heating System (ePATHS)

    Energy Technology Data Exchange (ETDEWEB)

    LaClair, Tim J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gao, Zhiming [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-04-20

    Bench testing of the Electrical PCM-Assisted Thermal Heating System (ePATHS) was completed at the Building Technologies Research and Integration Center (BTRIC) at the Oak Ridge National Laboratory (ORNL). The ePATHS is a thermal energy storage device designed to reduce the energy required from the battery for cabin heating of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). ORNL s testing of the ePATHS assessed three main aspects of operation of the device: 1.ePATHS charging evaluation: measure the time to charge and the energy input needed to fully charge the PCM for a range of different ambient conditions. 2.ePATHS Discharge Evaluations: measure the energy provided by the PCM HX, both during mode 1 and mode 2 operation, and confirm the cabin heating duration that can be provided by the ePATHS. This is the primary evaluation to validate the system performance, and an array of multiple ambient conditions and operating scenarios were tested. 3.Evaluation of Thermal Losses from the ePATHS during Cold Soak: this test will evaluate the performance of the insulation system for the ePATHS. The charged ePATHS undergoes a long-term soak in cold ambient temperature conditions, and the heat losses will be evaluated to validate that the performance meets the maximum energy loss requirement.

  2. Relations between Coherence and Path Information.

    Science.gov (United States)

    Bagan, Emilio; Bergou, János A; Cottrell, Seth S; Hillery, Mark

    2016-04-22

    We find two relations between coherence and path information in a multipath interferometer. The first builds on earlier results for the two-path interferometer, which used minimum-error state discrimination between detector states to provide the path information. For visibility, which was used in the two-path case, we substitute a recently defined l_{1} measure of quantum coherence. The second is an entropic relation in which the path information is characterized by the mutual information between the detector states and the outcome of the measurement performed on them, and the coherence measure is one based on relative entropy.

  3. Link prediction based on path entropy

    CERN Document Server

    Xu, Zhongqi; Yang, Jian

    2015-01-01

    Information theory has been taken as a prospective tool for quantifying the complexity of complex networks. In this paper, we first study the information entropy or uncertainty of a path using the information theory. Then we apply the path entropy to the link prediction problem in real-world networks. Specifically, we propose a new similarity index, namely Path Entropy (PE) index, which considers the information entropies of shortest paths between node pairs with penalization to long paths. Empirical experiments demonstrate that PE index outperforms the mainstream link predictors.

  4. Strategic Path Reliability in Information Networks

    OpenAIRE

    Kannan, Rajgopal; Sarangi, Sudipta; Iyengar, Sundaraja Sitharama

    2002-01-01

    We consider a model of an information network where nodes can fail and transmission of information is costly. The formation of paths in such networks is modeled as the Nash equilibrium of an N player routing game. The task of obtaining this equilibrium is shown to be NP-Hard. We derive analytical results to identify conditions under which the equilibrium path is congruent to well known paths such as the most reliable or cheapest neighbor path. The issue of characterizing off-equilibrium paths...

  5. Two Generations of Path Dependence in Economics?

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2010-01-01

    Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences – primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...... or economic processes have multiple possible paths of outcomes, rather than a unique path of equilibria. The selection among outcomes may depend on contingent choices or events – outcomes of path-dependent processes require a very relevant study – a perception of history....

  6. 大数据背景下网络众包驱动科技创新的机理及路径研究%Mechanism and Path of the Network Crowdsourcing Driving Science and Technology Innovation under the Background of Big Data

    Institute of Scientific and Technical Information of China (English)

    赵喜仓; 朱宾欣; 马志强

    2016-01-01

    增强科技创新能力是建设创新型国家、提高综合国力的关键,大数据时代的到来为科技创新领域带来了前所未有的机遇与挑战,网络众包这一新型创新模式应时而兴。紧紧把握时代发展主题,发现并描述大数据环境下科技创新的新变化、新要求、新问题,从动力源、集聚效应、协同效应和规模效应等方面探讨了网络众包驱动科技创新的机理,并创新性地提出了网络众包模式下的科技创新实现路径,以期为推动我国科技创新提供新思路。%Enhancing the ability of science and technology innovation is the key to build an innovative country and improve the comprehensive national strength .The arrival of the era of Big Data has brought unprecedented opportunities and chal‐lenges to science and technology innovation which leads in network crowdsourcing ,a new innovative model .In this paper , we firmly grasp the theme of the development of this era ,trying to find out and to describe the new changes ,new require‐ments and new issues in science and technology innovation in the background of Big Data .Exploring the driving mecha‐nism of the network crowdsourcing by using the power source analysis ,the combined effect analysis ,the synergistic effect analysis and the economics of scale analysis ,etc .,and innovatively putting forward the realization path of science and technology innovation by using the mode of network crowdsourcing in order to provide new ideas for China's promotion of science and technology innovation .

  7. Evaluation of guidewire path reproducibility.

    Science.gov (United States)

    Schafer, Sebastian; Hoffmann, Kenneth R; Noël, Peter B; Ionita, Ciprian N; Dmochowski, Jacek

    2008-05-01

    The number of minimally invasive vascular interventions is increasing. In these interventions, a variety of devices are directed to and placed at the site of intervention. The device used in almost all of these interventions is the guidewire, acting as a monorail for all devices which are delivered to the intervention site. However, even with the guidewire in place, clinicians still experience difficulties during the interventions. As a first step toward understanding these difficulties and facilitating guidewire and device guidance, we have investigated the reproducibility of the final paths of the guidewire in vessel phantom models on different factors: user, materials and geometry. Three vessel phantoms (vessel diameters approximately 4 mm) were constructed having tortuousity similar to the internal carotid artery from silicon tubing and encased in Sylgard elastomer. Several trained users repeatedly passed two guidewires of different flexibility through the phantoms under pulsatile flow conditions. After the guidewire had been placed, rotational c-arm image sequences were acquired (9 in. II mode, 0.185 mm pixel size), and the phantom and guidewire were reconstructed (512(3), 0.288 mm voxel size). The reconstructed volumes were aligned. The centerlines of the guidewire and the phantom vessel were then determined using region-growing techniques. Guidewire paths appear similar across users but not across materials. The average root mean square difference of the repeated placement was 0.17 +/- 0.02 mm (plastic-coated guidewire), 0.73 +/- 0.55 mm (steel guidewire) and 1.15 +/- 0.65 mm (steel versus plastic-coated). For a given guidewire, these results indicate that the guidewire path is relatively reproducible in shape and position.

  8. Attention trees and semantic paths

    Science.gov (United States)

    Giusti, Christian; Pieroni, Goffredo G.; Pieroni, Laura

    2007-02-01

    In the last few decades several techniques for image content extraction, often based on segmentation, have been proposed. It has been suggested that under the assumption of very general image content, segmentation becomes unstable and classification becomes unreliable. According to recent psychological theories, certain image regions attract the attention of human observers more than others and, generally, the image main meaning appears concentrated in those regions. Initially, regions attracting our attention are perceived as a whole and hypotheses on their content are formulated; successively the components of those regions are carefully analyzed and a more precise interpretation is reached. It is interesting to observe that an image decomposition process performed according to these psychological visual attention theories might present advantages with respect to a traditional segmentation approach. In this paper we propose an automatic procedure generating image decomposition based on the detection of visual attention regions. A new clustering algorithm taking advantage of the Delaunay- Voronoi diagrams for achieving the decomposition target is proposed. By applying that algorithm recursively, starting from the whole image, a transformation of the image into a tree of related meaningful regions is obtained (Attention Tree). Successively, a semantic interpretation of the leaf nodes is carried out by using a structure of Neural Networks (Neural Tree) assisted by a knowledge base (Ontology Net). Starting from leaf nodes, paths toward the root node across the Attention Tree are attempted. The task of the path consists in relating the semantics of each child-parent node pair and, consequently, in merging the corresponding image regions. The relationship detected in this way between two tree nodes generates, as a result, the extension of the interpreted image area through each step of the path. The construction of several Attention Trees has been performed and partial

  9. Communication path for extreme environments

    Science.gov (United States)

    Jorgensen, Charles C. (Inventor); Betts, Bradley J. (Inventor)

    2010-01-01

    Methods and systems for using one or more radio frequency identification devices (RFIDs), or other suitable signal transmitters and/or receivers, to provide a sensor information communication path, to provide location and/or spatial orientation information for an emergency service worker (ESW), to provide an ESW escape route, to indicate a direction from an ESW to an ES appliance, to provide updated information on a region or structure that presents an extreme environment (fire, hazardous fluid leak, underwater, nuclear, etc.) in which an ESW works, and to provide accumulated thermal load or thermal breakdown information on one or more locations in the region.

  10. Uncommon paths in quantum physics

    CERN Document Server

    Kazakov, Konstantin V

    2014-01-01

    Quantum mechanics is one of the most fascinating, and at the same time most controversial, branches of contemporary science. Disputes have accompanied this science since its birth and have not ceased to this day. Uncommon Paths in Quantum Physics allows the reader to contemplate deeply some ideas and methods that are seldom met in the contemporary literature. Instead of widespread recipes of mathematical physics, based on the solutions of integro-differential equations, the book follows logical and partly intuitional derivations of non-commutative algebra. Readers can directly penetrate the

  11. Gibbs Ensembles of Nonintersecting Paths

    CERN Document Server

    Borodin, Alexei

    2008-01-01

    We consider a family of determinantal random point processes on the two-dimensional lattice and prove that members of our family can be interpreted as a kind of Gibbs ensembles of nonintersecting paths. Examples include probability measures on lozenge and domino tilings of the plane, some of which are non-translation-invariant. The correlation kernels of our processes can be viewed as extensions of the discrete sine kernel, and we show that the Gibbs property is a consequence of simple linear relations satisfied by these kernels. The processes depend on infinitely many parameters, which are closely related to parametrization of totally positive Toeplitz matrices.

  12. On the path to differentiation

    DEFF Research Database (Denmark)

    Martinsen, Dorte Sindbjerg; Uygur, Ayca

    2014-01-01

    by examining the ‘path to differentiation’ within EU working time regulation as it has unfolded over time. It identifies the ‘opt-out’ as a means of differentiation adopted to overcome policy deadlocks within collective decision-making, albeit one with unforeseen consequences. In particular, the contribution...... investigates the causes and effects of differentiation by examining (1) its origin, (2) the ‘logic of variation’ or ‘opt-out spiral’ that spurs differentiation and (3) the implications of differentiation over time. We conclude that differentiation has dynamic and broad consequences that are likely to produce...

  13. Path of Chinese institutional modernization

    OpenAIRE

    Sahoo, Ganeswar

    2009-01-01

    We see the progress today that China has developed a treasure of modernity in terms of its World figure both in economic development and its strong military power with countless path of ups and downs in the past. We are more concerned with the historical study of its institutional modernization than a mere philosophical debate over its development and can discuss its various levels of struggle for ‘Substitute Modernity’2 since mid-19th century(the two opium wars) to till date.

  14. Paths and cycles of hypergraphs

    Institute of Scientific and Technical Information of China (English)

    王建方; Tony; T.Lee

    1999-01-01

    Hypergraphs are the most general structures in discrete mathematics. Acyclic hypergraphs have been proved very useful in relational databases. New systems of axioms for paths, connectivity and cycles of hypergraphs are constructed. The systems suit the structure properties of relational databases. The concepts of pseudo cycles and essential cycles of hypergraphs are introduced. They are relative to each other. Whether a family of cycles of a hypergraph is dependent or independent is defined. An enumeration formula for the maximum number of independent essential cycles of a hypergraph is given.

  15. Physarum Can Compute Shortest Paths

    CERN Document Server

    Bonifaci, Vincenzo; Varma, Girish

    2011-01-01

    A mathematical model has been proposed by biologists to describe the feedback mechanism used by the Physarum Polycephalum slime mold to adapt its tubular channels while foraging two food sources $s_0$ and $s_1$. We give a proof of the fact that, under this model, the mass of the mold will eventually converge to the shortest $s_0$-$s_1$ path of the network that the mold lies on, independently of the structure of the network or of the initial mass distribution. This matches the experimental observations by the biologists and can be seen as an example of a "natural algorithm", that is, an algorithm developed by evolution over millions of years.

  16. Deterministic Circular Self Test Path

    Institute of Scientific and Technical Information of China (English)

    WEN Ke; HU Yu; LI Xiaowei

    2007-01-01

    Circular self test path (CSTP) is an attractive technique for testing digital integrated circuits(IC) in the nanometer era, because it can easily provide at-speed test with small test data volume and short test application time. However, CSTP cannot reliably attain high fault coverage because of difficulty of testing random-pattern-resistant faults. This paper presents a deterministic CSTP (DCSTP) structure that consists of a DCSTP chain and jumping logic, to attain high fault coverage with low area overhead. Experimental results on ISCAS'89 benchmarks show that 100% fault coverage can be obtained with low area overhead and CPU time, especially for large circuits.

  17. Longest-path attacks on complex networks

    CERN Document Server

    Pu, Cunlai

    2014-01-01

    We investigate the longest-path attacks on complex networks. Specifically, we remove approximately the longest simple path from a network iteratively until there are no paths left in the network. We propose two algorithms, the random augmenting approach (RPA) and the Hamilton-path based approach (HPA), for finding the approximately longest simple path in a network. Results demonstrate that steps of longest-path attacks increase with network density linearly for random networks, while exponentially increasing for scale-free networks. The more homogeneous the degree distribution is, the more fragile the network, which is totally different from the previous results of node or edge attacks. HPA is generally more efficient than RPA in the longest-path attacks of complex networks. These findings further help us understand the vulnerability of complex systems, better protect complex systems, and design more tolerant complex systems.

  18. Classical and quantum dynamics from classical paths to path integrals

    CERN Document Server

    Dittrich, Walter

    2017-01-01

    Graduate students who wish to become familiar with advanced computational strategies in classical and quantum dynamics will find in this book both the fundamentals of a standard course and a detailed treatment of the time-dependent oscillator, Chern-Simons mechanics, the Maslov anomaly and the Berry phase, to name just a few topics. Well-chosen and detailed examples illustrate perturbation theory, canonical transformations and the action principle, and demonstrate the usage of path integrals. The fifth edition has been revised and enlarged to include chapters on quantum electrodynamics, in particular, Schwinger’s proper time method and the treatment of classical and quantum mechanics with Lie brackets and pseudocanonical transformations. It is shown that operator quantum electrodynamics can be equivalently described with c-numbers, as demonstrated by calculating the propagation function for an electron in a prescribed classical electromagnetic field.

  19. Field Test of a Remote Multi-Path CLaDS Methane Sensor

    Directory of Open Access Journals (Sweden)

    Genevieve Plant

    2015-08-01

    Full Text Available Existing technologies for quantifying methane emissions are often limited to single point sensors, making large area environmental observations challenging. We demonstrate the operation of a remote, multi-path system using Chirped Laser Dispersion Spectroscopy (CLaDS for quantification of atmospheric methane concentrations over extended areas, a technology that shows potential for monitoring emissions from wetlands.

  20. Obstacle avoidance and path planning for carrier aircraft launching

    Directory of Open Access Journals (Sweden)

    Wu Yu

    2015-06-01

    Full Text Available Launching safety and efficiency are important indexes to measure the fighting capacity of carrier. The study on path planning for taxi of carrier aircraft launching under actual deck environment is of great significance. In actual deck scheduling, manual command is applied to taxi of carrier aircraft, which has negative effects on the safety of staff and carrier aircraft launching. In consideration of both the safety and efficiency of carrier aircraft launching, the key elements of the problem are abstracted based on the analysis of deck environment, carrier aircraft maneuver performance and task requirements. According to the problem description, the mathematical model is established including various constraints. The carrier aircraft and the obstacles are reasonably simplified as circle and polygons respectively. What’s more, the proposed collision detection model reduces the calculations. Aimed at the features of model, the theory of model predictive control (MPC is applied to the path search. Then a dynamic weight heuristic function is designed and a dynamic multistep optimization algorithm is proposed. Taking the Nimitz-class aircraft carrier as an example, the paths from parking place to catapult are planned, which indicate the rationality of the model and the effectiveness of the algorithm by comparing the planning results under different simulation environments. The main contribution of research is the establishment of obstacle avoidance and path planning model. In addition, it provides the solution of model and technological foundations for comprehensive command and real-time decision-making of the carrier aircraft.

  1. Dual-path NMR receiver using double transceiver microcoils.

    Science.gov (United States)

    Pourmodheji, Hossein; Ghafar-Zadeh, Ebrahim; Magierowski, Sebastian

    2015-01-01

    We present a fully integrated CMOS dual path front-end receiver for NMR applications. Instead of conventional NMR systems which are using one transceiver coil, we propose a dual-path receiver in which it has two transceiver microcoils. This structure cancels the background signal and consequently improving the sensitivity. Spectral simulations of the dual-path receiver are used to verify cancellation of the background signal in this structure. The front-end receiver contains two differential low-noise amplifiers (LNA), two voltage buffers (for conventional mode), two phase shifters, two variable gain amplifiers (VGA), one differential LNA and voltage buffer at the end. This chain of dual-path receiver is designed for 21 MHz NMR settings. The front-end receiver achieves an input referred noise of 2.7 nV/√Hz and voltage gain of 80 dB. The chip is designed in a 0.13-μm CMOS technology and occupies an area of 1 mm × 2 mm.

  2. Path to Market for Compact Modular Fusion Power Cores

    Science.gov (United States)

    Woodruff, Simon; Baerny, Jennifer K.; Mattor, Nathan; Stoulil, Don; Miller, Ronald; Marston, Theodore

    2012-08-01

    The benefits of an energy source whose reactants are plentiful and whose products are benign is hard to measure, but at no time in history has this energy source been more needed. Nuclear fusion continues to promise to be this energy source. However, the path to market for fusion systems is still regularly a matter for long-term (20 + year) plans. This white paper is intended to stimulate discussion of faster commercialization paths, distilling guidance from investors, utilities, and the wider energy research community (including from ARPA-E). There is great interest in a small modular fusion system that can be developed quickly and inexpensively. A simple model shows how compact modular fusion can produce a low cost development path by optimizing traditional systems that burn deuterium and tritium, operating not only at high magnetic field strength, but also by omitting some components that allow for the core to become more compact and easier to maintain. The dominant hurdles to the development of low cost, practical fusion systems are discussed, primarily in terms of the constraints placed on the cost of development stages in the private sector. The main finding presented here is that the bridge from DOE Office of Science to the energy market can come at the Proof of Principle development stage, providing the concept is sufficiently compact and inexpensive that its development allows for a normal technology commercialization path.

  3. Extracting Critical Path Graphs from MPI Applications

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, M

    2005-07-27

    The critical path is one of the fundamental runtime characteristics of a parallel program. It identifies the longest execution sequence without wait delays. In other words, the critical path is the global execution path that inflicts wait operations on other nodes without itself being stalled. Hence, it dictates the overall runtime and knowing it is important to understand an application's runtime and message behavior and to target optimizations. We have developed a toolset that identifies the critical path of MPI applications, extracts it, and then produces a graphical representation of the corresponding program execution graph to visualize it. To implement this, we intercept all MPI library calls, use the information to build the relevant subset of the execution graph, and then extract the critical path from there. We have applied our technique to several scientific benchmarks and successfully produced critical path diagrams for applications running on up to 128 processors.

  4. Strategic Team AI Path Plans: Probabilistic Pathfinding

    Directory of Open Access Journals (Sweden)

    Tng C. H. John

    2008-01-01

    Full Text Available This paper proposes a novel method to generate strategic team AI pathfinding plans for computer games and simulations using probabilistic pathfinding. This method is inspired by genetic algorithms (Russell and Norvig, 2002, in that, a fitness function is used to test the quality of the path plans. The method generates high-quality path plans by eliminating the low-quality ones. The path plans are generated by probabilistic pathfinding, and the elimination is done by a fitness test of the path plans. This path plan generation method has the ability to generate variation or different high-quality paths, which is desired for games to increase replay values. This work is an extension of our earlier work on team AI: probabilistic pathfinding (John et al., 2006. We explore ways to combine probabilistic pathfinding and genetic algorithm to create a new method to generate strategic team AI pathfinding plans.

  5. Path modeling and process control

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar; Rodionova, O.; Pomerantsev, A.

    2007-01-01

    and having three or more stages. The methods are applied to a process control of a multi-stage production process having 25 variables and one output variable. When moving along the process, variables change their roles. It is shown how the methods of path modeling can be applied to estimate variables...... of the next stage with the purpose of obtaining optimal or almost optimal quality of the output variable. An important aspect of the methods presented is the possibility of extensive graphic analysis of data that can provide the engineer with a detailed view of the multi-variate variation in data.......Many production processes are carried out in stages. At the end of each stage, the production engineer can analyze the intermediate results and correct process parameters (variables) of the next stage. Both analysis of the process and correction to process parameters at next stage should...

  6. The Logic Behind Feynman's Paths

    Science.gov (United States)

    García Álvarez, Edgardo T.

    The classical notions of continuity and mechanical causality are left in order to reformulate the Quantum Theory starting from two principles: (I) the intrinsic randomness of quantum process at microphysical level, (II) the projective representations of symmetries of the system. The second principle determines the geometry and then a new logic for describing the history of events (Feynman's paths) that modifies the rules of classical probabilistic calculus. The notion of classical trajectory is replaced by a history of spontaneous, random and discontinuous events. So the theory is reduced to determining the probability distribution for such histories accordingly with the symmetries of the system. The representation of the logic in terms of amplitudes leads to Feynman rules and, alternatively, its representation in terms of projectors results in the Schwinger trace formula.

  7. Design of active N-path filters

    NARCIS (Netherlands)

    Darvishi, Milad; Zee, van der Ronan; Nauta, Bram

    2013-01-01

    A design methodology for synthesis of active N-path bandpass filters is introduced. Based on this methodology, a 0.1-to-1.2 GHz tunable 6th-order N-path channel-select filter in 65 nm LP CMOS is introduced. It is based on coupling N-path filters with gyrators, achieving a “flat” passband shape and h

  8. Path Planning Control for Mobile Robot

    Directory of Open Access Journals (Sweden)

    Amenah A.H. Salih

    2011-01-01

    Full Text Available Autonomous motion planning is important area of robotics research. This type of planning relieves human operator from tedious job of motion planning. This reduces the possibility of human error and increase efficiency of whole process. This research presents a new algorithm to plan path for autonomous mobile robot based on image processing techniques by using wireless camera that provides the desired image for the unknown environment . The proposed algorithm is applied on this image to obtain a optimal path for the robot. It is based on the observation and analysis of the obstacles that lying in the straight path between the start and the goal point by detecting these obstacles, analyzing and studying their shapes, positions and points of intersection with the straight path to find the nearly optimal path which connects the start and the goal point.This work has theoretical part and experimental part. The theoretical part includes building a MATLAB program which is applied to environment image to find the nearly optimal path .MATLAB - C++.NET interface is accomplished then to supply the path information for C++.NET program which is done for programming the pioneer mobile robot to achieve the desired path. The experimental part includes using wireless camera that takes an image for the environment and send it to the computer which processes this image and sends ( by wireless connection the resulted path information to robot which programmed in C++.NET program to walk according to this path.So, the overall system can be represented by:Wireless camera – computer – wireless connection for the mobile robot .The experimental work including some experiments shows that the developed mobile robot (pioneer p3-dx travels successfully from the start point and reach the goal point across the optimal path (according to time and power which is obtained as result of the proposed path planning algorithm introduced in this paper.

  9. A note on the path interval distance.

    Science.gov (United States)

    Coons, Jane Ivy; Rusinko, Joseph

    2016-06-01

    The path interval distance accounts for global congruence between locally incongruent trees. We show that the path interval distance provides a lower bound for the nearest neighbor interchange distance. In contrast to the Robinson-Foulds distance, random pairs of trees are unlikely to be maximally distant from one another under the path interval distance. These features indicate that the path interval distance should play a role in phylogenomics where the comparison of trees on a fixed set of taxa is becoming increasingly important.

  10. Continuous-Discrete Path Integral Filtering

    Directory of Open Access Journals (Sweden)

    Bhashyam Balaji

    2009-08-01

    Full Text Available A summary of the relationship between the Langevin equation, Fokker-Planck-Kolmogorov forward equation (FPKfe and the Feynman path integral descriptions of stochastic processes relevant for the solution of the continuous-discrete filtering problem is provided in this paper. The practical utility of the path integral formula is demonstrated via some nontrivial examples. Specifically, it is shown that the simplest approximation of the path integral formula for the fundamental solution of the FPKfe can be applied to solve nonlinear continuous-discrete filtering problems quite accurately. The Dirac-Feynman path integral filtering algorithm is quite simple, and is suitable for real-time implementation.

  11. Cooperative path planning of unmanned aerial vehicles

    CERN Document Server

    Tsourdos, Antonios; Shanmugavel, Madhavan

    2010-01-01

    An invaluable addition to the literature on UAV guidance and cooperative control, Cooperative Path Planning of Unmanned Aerial Vehicles is a dedicated, practical guide to computational path planning for UAVs. One of the key issues facing future development of UAVs is path planning: it is vital that swarm UAVs/ MAVs can cooperate together in a coordinated manner, obeying a pre-planned course but able to react to their environment by communicating and cooperating. An optimized path is necessary in order to ensure a UAV completes its mission efficiently, safely, and successfully.

  12. Langevin equation path integral ground state.

    Science.gov (United States)

    Constable, Steve; Schmidt, Matthew; Ing, Christopher; Zeng, Tao; Roy, Pierre-Nicholas

    2013-08-15

    We propose a Langevin equation path integral ground state (LePIGS) approach for the calculation of ground state (zero temperature) properties of molecular systems. The approach is based on a modification of the finite temperature path integral Langevin equation (PILE) method (J. Chem. Phys. 2010, 133, 124104) to the case of open Feynman paths. Such open paths are necessary for a ground state formulation. We illustrate the applicability of the method using model systems and the weakly bound water-parahydrogen dimer. We show that the method can lead to converged zero point energies and structural properties.

  13. Techniques and applications of path integration

    CERN Document Server

    Schulman, L S

    2005-01-01

    A book of techniques and applications, this text defines the path integral and illustrates its uses by example. It is suitable for advanced undergraduates and graduate students in physics; its sole prerequisite is a first course in quantum mechanics. For applications requiring specialized knowledge, the author supplies background material.The first part of the book develops the techniques of path integration. Topics include probability amplitudes for paths and the correspondence limit for the path integral; vector potentials; the Ito integral and gauge transformations; free particle and quadra

  14. Crystal Diagnostics MultiPath System™.

    Science.gov (United States)

    Stumpf, Curtis H; Zhao, Weidong; Bullard, Brian; Ammons, Christine; Devlin, Karl I; Niehaus, Gary D

    2014-01-01

    The Crystal Diagnostics MultiPath System™ provides rapid detection of Escherichia coli O157 in fresh raw ground beef, raw beeftrim, and spinach. The Crystal Diagnostics system combines patented Liquid Crystal technology with antibody-coated paramagnetic microspheres to selectively capture and detect E. coli O157 in food matrixes. This is the only liquid crystal-based biosensor commercially available for the detection of pathogens. The Crystal Diagnostics system expeditiously provides the sensitivity and accuracy of the U.S. Department of Agriculture Food Safety Inspection Service (USDA-FSIS) and the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA-BAM) methods for detecting as low as one CFU of E. coli O157 per 375 g of raw ground beef and raw beef trim, or 200 g of raw spinach. An internal inclusivity validation demonstrated detection of all 50 tested strains of . coli O157. The internal and independent laboratory tests demonstrate that the method is rapid and sensitive for detecting of E. coli O157 in fresh raw ground beef, beef trim, and spinach.

  15. A Path Planning Method for Robotic Belt Surface Grinding

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; YUN Chao

    2011-01-01

    The flexible contact and machining with wide strip are two prominent advantages for the robotic belt grinding system,which can be widely used to improve the surface quality and machining efficiency while finishing the workpieces with sculptured surfaces.There lacks research on grinding path planning with the constraint of curvature.With complicated contact between the contact wheel and the workpiece,the grinding paths for robot can be obtained by the theory of contact kinematics.The grinding process must satisfy the universal demands of the belt grinding technologies,and the most important thing is to make the contact wheel conform to the local geometrical features on the contact area.For the local surfaces with small curvature,the curve length between the neighboring cutting locations becomes longer to ensure processing efficiency.Otherwise,for the local areas with large curvature,the curve length becomes shorter to ensure machining accuracy.A series of planes are created to intersect with the target surface to be ground,and the corresponding sectional profile curves are obtained.For each curve,the curve length between the neighboring cutting points is optimized by inserting a cutter location at the local area with large curvatures.A method of generating the grinding paths including curve length spacing optimization is set up.The validity is completely approved by the off-line simulation,and during the grinding experiments with the method,the quality of surface is improved.The path planning method provides a theoretical support for the smooth and accuracy path of robotic surface grinding.

  16. The Ecologicalization and Return of Humanity of Science and Technology-A New Path on Eliminating Science and Technology Alienation%科技的生态化重塑与人性的归复--一种消解科技异化的新通路

    Institute of Scientific and Technical Information of China (English)

    魏巍; 刘伟; 张慧颖

    2015-01-01

    Based on traceability recovery and interpretation of the concept "alienation",this paper resolves various mani-festations and meanings of science and technology alienation,initially reveals the underlying causes of science and technolo-gy alienation that value rationality and utilitarianism were dislocated in the fundamental concepts of science and technology, and proposes governance concepts of ecologicalization of science and technology and return of humanity.%通过对“异化”概念的溯源追本和解读,透析科技异化的种种表现及内涵,初步揭示了科技异化产生的深层原因,即工具理性和功利主义在科技观念中的错位,并提出了科技生态化重塑与人性归复的治理观念。

  17. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance, The world model is represented as the knowledge data and stored in the knowledge base with rules. The expert system can find a collision-avoidance path . Otherwise, it shows the collision secton in which the moved object is blocked . Several examples for the different objects to pass throngli the different channels and to find a collision-free path have been testnd. The simulating resuks of the planner give out the planning sequence or blocked section(s) . The output information is useful for making decision of the robot motion and modifying the technological parameters of the world .

  18. Robotic Path Finding with Collision Avoidance Using Expert System

    Institute of Scientific and Technical Information of China (English)

    蔡自兴

    1989-01-01

    A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance,The world model is represented as the knowledge data and stored in the knowledge base with rules.The expert system can find a collision-avoidance path.Otherwise.it shows the collision secton in which the moved object is blocked,Several examples for the different objects to pass through the different channels and to find a collision-free path have been tested.The simulating results of the palnner give out the planning sequence or blocked section(s).The output information is useful for making decision of the robot motion and modifyting the technological parameters of the world.

  19. PathEdEx - Uncovering high-explanatory visual diagnostics heuristics using digital pathology and multiscale gaze data

    National Research Council Canada - National Science Library

    Dmitriy Shin; Mikhail Kovalenko; Ilker Ersoy; Yu Li; Donald Doll; Chi-Ren Shyu; Richard Hammer

    2017-01-01

    ...: Here, we present PathEdEx, an informatics computational framework that incorporates whole-slide digital pathology imaging with multiscale gaze-tracking technology to create web-based interactive...

  20. ICT Design Unsustainability & the Path toward Environmentally Sustainable Technologies

    OpenAIRE

    Bibri, Mohamed

    2009-01-01

    This study endeavors to investigate the negative environmental impacts of the prevailing ICT design approaches and to explore some potential remedies for ICT design unsustainability from environmental and corporate sustainability perspectives. More specifically, it aims to spotlight key environmental issues related to ICT design, including resource depletion; GHG emissions resulting from energy-intensive consumption; toxic waste disposal; and hazardous chemicals use; and also to shed light on...

  1. Astrobiology Science and Technology: A Path to Future Discovery

    Science.gov (United States)

    Meyer, M. A.; Lavaery, D. B.

    2001-01-01

    The Astrobiology Program is described. However, science-driven robotic exploration of extreme environments is needed for a new era of planetary exploration requiring biologically relevant instrumentation and extensive, autonomous operations on planetary surfaces. Additional information is contained in the original extended abstract.

  2. Argillite And Crystalline Disposal Research: Accomplishments And Path-Forward.

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, Kevin A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-01

    The intention of this document is to provide a path-forward for research and development (R&D) for two host rock media-specific (argillite and crystalline) disposal research work packages within the Used Fuel Disposition Campaign (UFDC). The two work packages, Argillite Disposal R&D and Crystalline Disposal R&D, support the achievement of the overarching mission and objectives of the Department of Energy Office of Nuclear Energy Fuel Cycle Technologies Program. These two work packages cover many of the fundamental technical issues that will have multiple implications to other disposal research work packages by bridging knowledge gaps to support the development of the safety case. The path-forward begins with the assumption of target dates that are set out in the January 2013 DOE Strategy for the Management and Disposal of Used Nuclear Fuel and High-Level Radioactive Waste (http://energy.gov/downloads/strategy-management-and-disposal-used-nuclear-fuel-and-high-levelradioactive- waste). The path-forward will be maintained as a living document and will be updated as needed in response to available funding and the progress of multiple R&D tasks in the Used Fuel Disposition Campaign and the Fuel Cycle Technologies Program. This path forward is developed based on the report of “Used Fuel Disposition Campaign Disposal Research and Development Roadmap (FCR&D-USED- 2011-000065 REV0)” (DOE, 2011). This document delineates the goals and objectives of the UFDC R&D program, needs for generic disposal concept design, and summarizes the prioritization of R&D issues.

  3. LISA and LISA PathFinder, the endeavour to detect low frequency GWs

    CERN Document Server

    Araujo, H; Chmeissani, M; Conchillo, A; García-Berro, E; Grimani, C; Hajdas, W; Lobo, A; Martínez, L; Nofrarias, M; Ortega, J A; Puigdengoles, C; Ramos-Castro, J; Sanjuan, J; Wass, P; Xirgu, X; Araujo, Henrique; Boatella, Cesar; Chmeissani, Mokhtar; Conchillo, Aleix; Garcia-Berro, Enrique; Grimani, Catia; Hajdas, Wojtek; Lobo, Alberto; Martinez, Lluis; Nofrarias, Miquel; Ortega, Jose Antonio; Puigdengoles, Carles; Ramos-Castro, Juan; Sanjuan, Josep; Wass, Peter; Xirgu, Xevi

    2006-01-01

    This is a review about LISA and its technology demonstrator, LISA PathFinder. We first describe the conceptual problems which need to be overcome in order to set up a working interferometric detector of low frequency Gravitational Waves (GW), then summarise the solutions to them as currently conceived by the LISA mission team. This will show that some of these solutions require new technological abilities which are still under development, and which need proper test before being fully implemented. LISA PathFinder (LPF) is the the testbed for such technologies. The final part of the paper will address the ideas and concepts behind the PathFinder as well as their impact on LISA.

  4. Joint modeling of constrained path enumeration and path choice behavior: a semi-compensatory approach

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2010-01-01

    A behavioural and a modelling framework are proposed for representing route choice from a path set that satisfies travellers’ spatiotemporal constraints. Within the proposed framework, travellers’ master sets are constructed by path generation, consideration sets are delimited according to spatio...... constraints are related to travellers’ socio-economic characteristics and that path choice is related to minimizing time and avoiding congestion....

  5. On the Path to SunShot - Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2016-05-01

    The halfway mark of the SunShot Initiative’s 2020 target date is a good time to take stock: How much progress has been made? What have we learned? What barriers and opportunities must still be addressed to ensure that solar technologies achieve cost parity in 2020 and realize their full potential in the decades beyond? To answer these questions, the Solar Energy Technology Office launched the On the Path to SunShot series in early 2015 in collaboration with the National Renewable Energy Laboratory (NREL) and with contributions from Lawrence Berkeley National Laboratory (LBNL), Sandia National Laboratories (SNL), and Argonne National Laboratory (ANL). The reports focus on the areas of technology development, systems integration, and market enablers.

  6. White Noise Path Integrals in Stochastic Neurodynamics

    Science.gov (United States)

    Carpio-Bernido, M. Victoria; Bernido, Christopher C.

    2008-06-01

    The white noise path integral approach is used in stochastic modeling of neural activity, where the primary dynamical variables are the relative membrane potentials, while information on transmembrane ionic currents is contained in the drift coefficient. The white noise path integral allows a natural framework and can be evaluated explicitly to yield a closed form for the conditional probability density.

  7. Cost allocation in shortest path games

    NARCIS (Netherlands)

    Voorneveld, M.; Grahn, S.

    2001-01-01

    A class of cooperative games arising from shortest path problems is dened These shortest path games are shown to be totally balanced and allow a population monotonic allocation scheme Possible methods for obtaining core elements are indicated rst by relating to the allocation rules in taxation and b

  8. The Path of Carbon in Photosynthesis VI.

    Science.gov (United States)

    Calvin, M.

    1949-06-30

    This paper is a compilation of the essential results of our experimental work in the determination of the path of carbon in photosynthesis. There are discussions of the dark fixation of photosynthesis and methods of separation and identification including paper chromatography and radioautography. The definition of the path of carbon in photosynthesis by the distribution of radioactivity within the compounds is described.

  9. Collaborative path planning for a robotic wheelchair.

    Science.gov (United States)

    Zeng, Qiang; Teo, Chee Leong; Rebsamen, Brice; Burdet, Etienne

    2008-11-01

    Generating a path to guide a wheelchair's motion faces two challenges. First, the path is located in the human environment and that is usually unstructured and dynamic. Thus, it is difficult to generate a reliable map and plan paths on it by artificial intelligence. Second, the wheelchair, whose task is to carry a human user, should move on a smooth and comfortable path adapted to the user's intentions. To meet these challenges, we propose that the human operator and the robot interact to create and gradually improve a guide path. This paper introduces design tools to enable an intuitive interaction, and reports experiments performed with healthy subjects in order to investigate this collaborative path learning strategy. We analyzed features of the optimal paths and user evaluation in representative conditions. This was complemented by a questionnaire filled out by the subjects after the experiments. The results demonstrate the effectiveness of this approach, and show the utility and complementarity of the tools to design ergonomic guide paths.

  10. Path Minima Queries in Dynamic Weighted Trees

    DEFF Research Database (Denmark)

    Davoodi, Pooya; Brodal, Gerth Stølting; Satti, Srinivasa Rao

    2011-01-01

    In the path minima problem on a tree, each edge is assigned a weight and a query asks for the edge with minimum weight on a path between two nodes. For the dynamic version of the problem, where the edge weights can be updated, we give data structures that achieve optimal query time\\todo{what about...

  11. Multi-block and path modelling procedures

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2008-01-01

    The author has developed a unified theory of path and multi-block modelling of data. The data blocks are arranged in a directional path. Each data block can lead to one or more data blocks. It is assumed that there is given a collection of input data blocks. Each of them is supposed to describe one...

  12. Two Generations of Path Dependence in Economics?

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2010-01-01

    Even if there is no fully articulated and generally accepted theory of Path Dependence it has eagerly been taken up across a wide range of social sciences – primarily coming from economics. Path Dependence is most of all a metaphor that offers reason to believe, that some political, social...

  13. Adaptively Ubiquitous Learning in Campus Math Path

    Science.gov (United States)

    Shih, Shu-Chuan; Kuo, Bor-Chen; Liu, Yu-Lung

    2012-01-01

    The purposes of this study are to develop and evaluate the instructional model and learning system which integrate ubiquitous learning, computerized adaptive diagnostic testing system and campus math path learning. The researcher first creates a ubiquitous learning environment which is called "adaptive U-learning math path system". This…

  14. Graphic method for analyzing common path interferometers

    DEFF Research Database (Denmark)

    Glückstad, J.

    1998-01-01

    Common path interferometers are widely used for visualizing phase disturbances and fluid flows. They are attractive because of the inherent simplicity and robustness in the setup. A graphic method will be presented for analyzing and optimizing filter parameters in common path interferometers....

  15. Robot path planning using genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents a strategy for soccer robot path planning using genetic algorithms for which, real number coding method is used, to overcome the defects of binary coding method, and the double crossover operation a dopted, to avoid the common defect of early convergence and converge faster than the standard genetic algo rithms concludes from simulation results that the method is effective for robot path planning.

  16. Consistent Partial Least Squares Path Modeling

    NARCIS (Netherlands)

    Dijkstra, Theo K.; Henseler, Jörg

    2015-01-01

    This paper resumes the discussion in information systems research on the use of partial least squares (PLS) path modeling and shows that the inconsistency of PLS path coefficient estimates in the case of reflective measurement can have adverse consequences for hypothesis testing. To remedy this, the

  17. Inked Careers: Tattooing Professional Paths

    Directory of Open Access Journals (Sweden)

    Gabriela DeLuca

    2016-12-01

    Full Text Available The concept of career has an interdisciplinary and historical constitution, which includes persons, groups, organizations and society. Given that, we aim to deepen the interactionist notion of career from the understanding of a deviant path, supported by a theory and a method appropriated to the cited call for interdisciplinary approaches. Dilemmas (Hughes, 1958 and conflicts (Hughes, 1937 emerged as important analytical categories. Although necessary, these two concepts were not sufficient to contemplate analyses in their entirety. For this reason we conceptualized a third possibility of controversy during a career: the inquiries. The study followed the Narrative method to analyze objective and subjective changes during a tattoo artist’s career through interviews and informal conversations carried out over 22 months. The discussion presents three main contributions. Theoretically, a new understanding of the concept of careers, linking past, present and future and the idea of non-linearity of experienced and envisioned careers. Methodologically, suggesting orientations for future career studies such as the use of turning points as a methodological tool and the investigation of deviant fields. Finally, our defense of the interactionist perspective as suitable for career studies, since it allows the investigation of deviant elements.

  18. Decision paths in complex tasks

    Science.gov (United States)

    Galanter, Eugene

    1991-01-01

    Complex real world action and its prediction and control has escaped analysis by the classical methods of psychological research. The reason is that psychologists have no procedures to parse complex tasks into their constituents. Where such a division can be made, based say on expert judgment, there is no natural scale to measure the positive or negative values of the components. Even if we could assign numbers to task parts, we lack rules i.e., a theory, to combine them into a total task representation. We compare here two plausible theories for the amalgamation of the value of task components. Both of these theories require a numerical representation of motivation, for motivation is the primary variable that guides choice and action in well-learned tasks. We address this problem of motivational quantification and performance prediction by developing psychophysical scales of the desireability or aversiveness of task components based on utility scaling methods (Galanter 1990). We modify methods used originally to scale sensory magnitudes (Stevens and Galanter 1957), and that have been applied recently to the measure of task 'workload' by Gopher and Braune (1984). Our modification uses utility comparison scaling techniques which avoid the unnecessary assumptions made by Gopher and Braune. Formula for the utility of complex tasks based on the theoretical models are used to predict decision and choice of alternate paths to the same goal.

  19. Gerbertian paths for the Jubilee

    Science.gov (United States)

    Sigismondi, Costantino

    2015-04-01

    Gerbert before becoming Pope Sylvester II came several times in Rome, as reported in his Letters and in the biography of Richerus. Eight places in Rome can be connected with Gerbertian memories. 1. The Cathedral of St. John in the Lateran where the gravestone of his tumb is still preserved near the Holy Door; 2. the “Basilica Hierusalem” (Santa Croce) where Gerbert had the stroke on May 3rd 1003 which lead him to death on May 12th; 3. the Aventine hill, with the church of the Knights of Malta in the place where the palace of the Ottonian Emperors was located; 4. the church of St. Bartholomew in the Tiber Island built in 997 under Otto III; 5. the Obelisk of Augustus in Montecitorio to remember the relationship between Gerbert, Astronomy and numbers which led the birth of the legends on Gerbert magician; 6. St. Mary Major end of the procession of August 15, 1000; 7. St. Paul outside the walls with the iconography of the Popes and 8. St. Peter's tumb end of all Romaei pilgrimages. This Gerbertian path in Rome suggests one way to accomplish the pilgrimage suggested by Pope Francis in the Bulla Misericordiae Vultus (14) of indiction of the new Jubilee.

  20. Feynman Path Integrals Over Entangled States

    CERN Document Server

    Green, A G; Keeling, J; Simon, S H

    2016-01-01

    The saddle points of a conventional Feynman path integral are not entangled, since they comprise a sequence of classical field configurations. We combine insights from field theory and tensor networks by constructing a Feynman path integral over a sequence of matrix product states. The paths that dominate this path integral include some degree of entanglement. This new feature allows several insights and applications: i. A Ginzburg-Landau description of deconfined phase transitions. ii. The emergence of new classical collective variables in states that are not adiabatically continuous with product states. iii. Features that are captured in product-state field theories by proliferation of instantons are encoded in perturbative fluctuations about entangled saddles. We develop a general formalism for such path integrals and a couple of simple examples to illustrate their utility.

  1. Critical Review of Path Integral Formulation

    CERN Document Server

    Fujita, Takehisa

    2008-01-01

    The path integral formulation in quantum mechanics corresponds to the first quantization since it is just to rewrite the quantum mechanical amplitude into many dimensional integrations over discretized coordinates $x_n$. However, the path integral expression cannot be connected to the dynamics of classical mechanics, even though, superficially, there is some similarity between them. Further, the field theory path integral in terms of many dimensional integrations over fields does not correspond to the field quantization. We clarify the essential difference between Feynman's original formulation of path integral in QED and the modern version of the path integral method prevailing in lattice field theory calculations, and show that the former can make a correct second quantization while the latter cannot quantize fields at all and its physical meaning is unknown.

  2. Research of the path optimization in agricultural water-saving irrigation and canal system water distribution in Ant colony algorithm

    Directory of Open Access Journals (Sweden)

    Deng Lei Lei

    2016-01-01

    Full Text Available To realize the management and control of the water-saving irrigation of the path pipeline distribution in field plots, get the terrain information through remote sensing technology and analyze the path and the amount of the water in the field plots by the ant colony algorithm according to the matter of the low generality in most parts in China. The result shows that the rules were put forward with shorter path, smaller cost and the most utilization of water eventually. It can be widely used in most areas which is lack of water and scientific technology.

  3. Research on Intra- product Specialization, Technology Diffusion and Path of Technology Progress --Based on Spengler Model%产品内分工、技术扩散与我国技术进步路径——基于Spengler模型的拓展分析

    Institute of Scientific and Technical Information of China (English)

    安果; 伍江

    2012-01-01

    This paper extends Spengler vertical integration model into technology foreclosure model, exploring the technology shift condition to the host country, for host country to construct emerging industry by such intra -product technology transferring which easily incurs repeat contracture and import, and hinders e- merging industry's technology disseminating.%本文在综述技术创新与扩散理论文献的基础上,以Spengler纵向一体化模型为基础,构建了一个拓展的技术圈定模型,分析了产品内分工背景下国际间技术扩散的条件,提出,如果通过模仿创新更新产业的技术基础,容易导致技术引进国长期的技术锁定,陷入重复引进的循环中。

  4. A novel communication mechanism based on node potential multi-path routing

    Science.gov (United States)

    Bu, Youjun; Zhang, Chuanhao; Jiang, YiMing; Zhang, Zhen

    2016-10-01

    With the network scales rapidly and new network applications emerge frequently, bandwidth supply for today's Internet could not catch up with the rapid increasing requirements. Unfortunately, irrational using of network sources makes things worse. Actual network deploys single-next-hop optimization paths for data transmission, but such "best effort" model leads to the imbalance use of network resources and usually leads to local congestion. On the other hand Multi-path routing can use the aggregation bandwidth of multi paths efficiently and improve the robustness of network, security, load balancing and quality of service. As a result, multi-path has attracted much attention in the routing and switching research fields and many important ideas and solutions have been proposed. This paper focuses on implementing the parallel transmission of multi next-hop data, balancing the network traffic and reducing the congestion. It aimed at exploring the key technologies of the multi-path communication network, which could provide a feasible academic support for subsequent applications of multi-path communication networking. It proposed a novel multi-path algorithm based on node potential in the network. And the algorithm can fully use of the network link resource and effectively balance network link resource utilization.

  5. Path Specific Register Design to Reduce Standby Power Consumption

    Directory of Open Access Journals (Sweden)

    Emre Salman

    2011-04-01

    Full Text Available A methodology is proposed to design low leakage registers by considering the type of timing path, i.e., short or long, and type of register, i.e., launching or capturing. Three different dual threshold voltage registers are developed where each register trades, depending upon the timing path, a different timing constraint for reducing the leakage current. For example, the first proposed register is used as a launching register in a noncritical path, trading clock-to-Q delay for leakage current. Other timing constraints such as setup and hold times are maintained the same not to introduce any timing violations. Alternatively, the second and third registers, trade, respectively, setup time and hold time for leakage current while maintaining clock-to-Q delay constant. The effect of the proposed methodology on leakage current is investigated for four technology nodes. The overall reduction in the leakage current of a register can exceed 90% while maintaining the clock frequency and other design parameters such as area and dynamic power the same. Three ISCAS 89 benchmark circuits are utilized to evaluate the methodology, demonstrating, on average, 23% reduction in the overall leakage current.

  6. Reaction path synthesis methodology for waste minimization

    Institute of Scientific and Technical Information of China (English)

    HU; Shanying; LI; Mingheng; LI; Yourun; SHEN; Jingzhu; LIU

    2004-01-01

    It is a key step for reducing waste generation in chemical processes to design optimal reaction paths. In this paper, methods of waste minimization for reaction path synthesis problems are proposed to realize eco-industrial production mode with minimum waste emission. A new conception of simple stoichiometric reaction is presented for reaction path synthesis problem. All simple stoichiometric reactions can be obtained by mathematical transformation for atom matrix of a reaction system. Based on the conception, a two-tier optimization method for complex reaction path synthesis problems is addressed. The first step is to determine the economic optimal overall reactions, and the second step to decompose each overall reaction into several sub-reactions and find out the best thermodynamic feasible reaction path. Further, a method of reaction path synthesis with waste closed-cycle is proposed based on simple stoichiometric reactions for achieving zero waste emission to poly-generation problem of multi-products. Case studies show that the proposed methods can efficiently solve practical reaction path synthesis problems.

  7. Robot path planning using a genetic algorithm

    Science.gov (United States)

    Cleghorn, Timothy F.; Baffes, Paul T.; Wang, Liu

    1988-01-01

    Robot path planning can refer either to a mobile vehicle such as a Mars Rover, or to an end effector on an arm moving through a cluttered workspace. In both instances there may exist many solutions, some of which are better than others, either in terms of distance traversed, energy expended, or joint angle or reach capabilities. A path planning program has been developed based upon a genetic algorithm. This program assumes global knowledge of the terrain or workspace, and provides a family of good paths between the initial and final points. Initially, a set of valid random paths are constructed. Successive generations of valid paths are obtained using one of several possible reproduction strategies similar to those found in biological communities. A fitness function is defined to describe the goodness of the path, in this case including length, slope, and obstacle avoidance considerations. It was found that with some reproduction strategies, the average value of the fitness function improved for successive generations, and that by saving the best paths of each generation, one could quite rapidly obtain a collection of good candidate solutions.

  8. Nonholonomic catheter path reconstruction using electromagnetic tracking

    Science.gov (United States)

    Lugez, Elodie; Sadjadi, Hossein; Akl, Selim G.; Fichtinger, Gabor

    2015-03-01

    Catheter path reconstruction is a necessary step in many clinical procedures, such as cardiovascular interventions and high-dose-rate brachytherapy. To overcome limitations of standard imaging modalities, electromagnetic tracking has been employed to reconstruct catheter paths. However, tracking errors pose a challenge in accurate path reconstructions. We address this challenge by means of a filtering technique incorporating the electromagnetic measurements with the nonholonomic motion constraints of the sensor inside a catheter. The nonholonomic motion model of the sensor within the catheter and the electromagnetic measurement data were integrated using an extended Kalman filter. The performance of our proposed approach was experimentally evaluated using the Ascension's 3D Guidance trakStar electromagnetic tracker. Sensor measurements were recorded during insertions of an electromagnetic sensor (model 55) along ten predefined ground truth paths. Our method was implemented in MATLAB and applied to the measurement data. Our reconstruction results were compared to raw measurements as well as filtered measurements provided by the manufacturer. The mean of the root-mean-square (RMS) errors along the ten paths was 3.7 mm for the raw measurements, and 3.3 mm with manufacturer's filters. Our approach effectively reduced the mean RMS error to 2.7 mm. Compared to other filtering methods, our approach successfully improved the path reconstruction accuracy by exploiting the sensor's nonholonomic motion constraints in its formulation. Our approach seems promising for a variety of clinical procedures involving reconstruction of a catheter path.

  9. Conceptual Soundness, Metric Development, Benchmarking, and Targeting for PATH Subprogram Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Mosey. G.; Doris, E.; Coggeshall, C.; Antes, M.; Ruch, J.; Mortensen, J.

    2009-01-01

    The objective of this study is to evaluate the conceptual soundness of the U.S. Department of Housing and Urban Development (HUD) Partnership for Advancing Technology in Housing (PATH) program's revised goals and establish and apply a framework to identify and recommend metrics that are the most useful for measuring PATH's progress. This report provides an evaluative review of PATH's revised goals, outlines a structured method for identifying and selecting metrics, proposes metrics and benchmarks for a sampling of individual PATH programs, and discusses other metrics that potentially could be developed that may add value to the evaluation process. The framework and individual program metrics can be used for ongoing management improvement efforts and to inform broader program-level metrics for government reporting requirements.

  10. Path Planning and Tracking for Vehicle Parallel Parking Based on Preview BP Neural Network PID Controller

    Institute of Scientific and Technical Information of China (English)

    季学武; 王健; 赵又群; 刘亚辉; 臧利国; 李波

    2015-01-01

    In order to diminish the impacts of external disturbance such as parking speed fluctuation and model un-certainty existing in steering kinematics, this paper presents a parallel path tracking method for vehicle based on pre-view back propagation (BP) neural network PID controller. The forward BP neural network can adjust the parameters of PID controller in real time. The preview time is optimized by considering path curvature, change in curvature and road boundaries. A fuzzy controller considering barriers and different road conditions is built to select the starting po-sition. In addition, a kind of path planning technology satisfying the requirement of obstacle avoidance is introduced. In order to solve the problem of discontinuous curvature, cubic B spline curve is used for curve fitting. The simulation results and real vehicle tests validate the effectiveness of the proposed path planning and tracking methods.

  11. Scalable fiber integrated source for higher-dimensional path-entangled photonic quNits

    CERN Document Server

    Schaeff, Christoph; Lapkiewicz, Radek; Fickler, Robert; Ramelow, Sven; Zeilinger, Anton

    2012-01-01

    Integrated photonic circuits offer the possibility for complex quantum optical experiments in higher-dimensional photonic systems. However, the advantages of integration and scalability can only be fully utilized with the availability of a source for higher-dimensional entangled photons. Here, a novel fiber integrated source for path-entangled photons in the telecom band at 1.55\\mum using only standard fiber technology is presented. Due to the special design the source shows good scalability towards higher-dimensional entangled photonic states (quNits), while path entanglement offers direct compatibility with on-chip path encoding. We present an experimental realization of a path-entangled two-qubit source. A very high quality of entanglement is verified by various measurements, i.a. a tomographic state reconstruction is performed leading to a background corrected fidelity of (99.45+-0.06)%. Moreover, we describe an easy method for extending our source to arbitrarily high dimensions.

  12. Science system path-dependencies and their influences: nanotechnology research in Russia.

    Science.gov (United States)

    Karaulova, Maria; Gök, Abdullah; Shackleton, Oliver; Shapira, Philip

    In this paper, we study the influence of path dependencies on the development of an emerging technology in a transitional economy. Our focus is the development of nanotechnology in Russia in the period between 1990 and 2012. By examining outputs, publication paths and collaboration patterns, we identify a series of factors that help to explain Russia's limited success in leveraging its ambitious national nanotechnology initiative. The analysis highlights four path-dependent tendencies of Russian nanotechnology research: publication pathways and the gatekeeping role of the Russian Academy of Sciences; increasing geographical and institutional centralisation of nanotechnology research; limited institutional diffusion; and patterns associated with the internationalisation of Russian research. We discuss policy implications related to path dependence, nanotechnology research in Russia and to the broader reform of the Russian science system.

  13. Fluctuating paths and fields Festschrift Kleinert (Hagen)

    CERN Document Server

    Bachmann, M; Schmidt, H J; Janke, W

    2001-01-01

    This volume covers the following fields: path integrals, quantum field theory, variational perturbation theory, phase transitions and critical phenomena, topological defects, strings and membranes, gravitation and cosmology. Contents: Path Integrals and Quantum Mechanics: Semiclassical Quantum Mechanics: A Path-Integral Approach (B R Holstein); Conjecture on the Reality of Spectra of Non-Hermitian Hamiltonians (C M Bender et al.); Time-Transformation Approach to q -Deformed Objects (A Inomata); Characterizing Volume Forms (P Cartier et al.); Vassiliev Invariants and Functional Integration (L H

  14. Path integral representations on the complex sphere

    Energy Technology Data Exchange (ETDEWEB)

    Grosche, C. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2007-08-15

    In this paper we discuss the path integral representations for the coordinate systems on the complex sphere S{sub 3C}. The Schroedinger equation, respectively the path integral, separates in exactly 21 orthogonal coordinate systems. We enumerate these coordinate systems and we are able to present the path integral representations explicitly in the majority of the cases. In each solution the expansion into the wave-functions is stated. Also, the kernel and the corresponding Green function can be stated in closed form in terms of the invariant distance on the sphere, respectively on the hyperboloid. (orig.)

  15. Non Abelian Dual Maps in Path Space

    CERN Document Server

    Martin, I

    1999-01-01

    We study an extension of the procedure to construct duality transformations among abelian gauge theories to the non abelian case using a path space formulation. We define a pre-dual functional in path space and introduce a particular non local map among Lie algebra valued 1-form functionals that reduces to the ordinary Hodge-* duality map of the abelian theories. Further, we establish a full set of equations on path space representing the ordinary Yang Mills equations and Bianchi identities of non abelian gauge theories of 4-dimensional euclidean space.

  16. Extending the application of critical path methods.

    Science.gov (United States)

    Coffey, R J; Othman, J E; Walters, J I

    1995-01-01

    Most health care organizations are using critical pathways in an attempt to reduce the variation in patient care, improve quality, enhance communication, and reduce costs. Virtually all of the critical path efforts to date have developed tables of treatments, medications, and so forth by day and have displayed them in a format known as a Gantt chart. This article presents a methodology for identifying the true "time-limiting" critical path, describes three additional methods for presenting the information--the network, precedent, and resource formats--and shows how these can significantly enhance current critical path efforts.

  17. INVESTMENT DEVELOPMENT PATH – CONCEPT AND TERMS

    Directory of Open Access Journals (Sweden)

    Ovidiu Serafim TRUFIN

    2015-04-01

    Full Text Available This article aims to analyze and explain the traditional model of Investment Development Path with new teoretical approaches. Investment Develoment Path is the latest theory about foreign direct investment and explains the relationship between a country’s development level and international investment position of a country. It has become a necessity in this research field of Romanian economy to establish a idiosyncratic model for evolution of inflows and outflows of Foreign Direct Investments after 1990. Also, persistent confusion between static and dynamic nature in using appropriate economic Romanian terms is removed. General theoretical approach is enhanced with new elements of schematic theorizing of Stages of Investment Development Path.

  18. Rotational path removable partial denture design.

    Science.gov (United States)

    Jacobson, T E; Krol, A J

    1982-10-01

    A detailed description of a rotational path of insertion design for removable partial dentures has been presented. By minimizing the use of conventional clasps, this technique offers some advantages. Rotational path designs may minimize adverse periodontal response to a removable partial denture by reducing plaque accumulation and may be applied in esthetically demanding situations. The design concept involves the use of rigid retentive components that gain access to undercut areas through a rotational path of insertion. These rigid components satisfy the basic requirements of conventional direct retained design.

  19. Quantum Adiabatic Evolution Algorithms with Different Paths

    CERN Document Server

    Farhi, E; Gutmann, S; Farhi, Edward; Goldstone, Jeffrey; Gutmann, Sam

    2002-01-01

    In quantum adiabatic evolution algorithms, the quantum computer follows the ground state of a slowly varying Hamiltonian. The ground state of the initial Hamiltonian is easy to construct; the ground state of the final Hamiltonian encodes the solution of the computational problem. These algorithms have generally been studied in the case where the "straight line" path from initial to final Hamiltonian is taken. But there is no reason not to try paths involving terms that are not linear combinations of the initial and final Hamiltonians. We give several proposals for randomly generating new paths. Using one of these proposals, we convert an algorithmic failure into a success.

  20. Test Derivation Through Critical Path Transitions

    Institute of Scientific and Technical Information of China (English)

    李卫东; 魏道政

    1992-01-01

    In this paper, a new technique called test derivation is presented,aiming at the promotion of the random testing efficiency for combinational circuits,Combined with a fault simulator based on critical path tracing method,we introduce the concept of seed test derivation and attempt to generate a group of new tests from the seed test by means of critical path transition.The neccessary conditions and efficient algorithms are proposed to guarantee the usefulness of the newly derived tests and the correctness of the critical path transitions.Also,examples are given to demonstrate the effectiveness of the technique.

  1. Compact Stellarator Path to DEMO

    Science.gov (United States)

    Lyon, J. F.

    2007-11-01

    Issues for a DEMO reactor are sustaining an ignited/high-Q plasma in steady state, avoiding disruptions and large variations in power flux to the wall, adequate confinement of thermal plasma and alpha-particles, control of a burning plasma, particle and power handling, etc. Compact stellarators have key advantages -- steady-state high-plasma-density operation without external current drive or disruptions, stability without a close conducting wall or active feedback systems, and low recirculating power -- in addition to moderate plasma aspect ratio, good confinement, and high-beta potential. The ARIES-CS study established that compact stellarators can be competitive with tokamaks as reactors. Many of the issues for a compact stellarator DEMO can be answered using results from large tokamaks, ITER D-T experiments and fusion materials, technology and component development programs, in addition to stellarators in operation, under construction or in development. However, a large next-generation stellarator will be needed to address some physics issues: size scaling and confinement at higher parameters, burning plasma issues, and operation with a strongly radiative divertor. Technology issues include simpler coils, structure, and divertor fabrication, and better cost information.

  2. Workability: The Path to Entrepreneurship

    Directory of Open Access Journals (Sweden)

    Darline Maria Santos Bulhões

    2016-07-01

    Full Text Available Since the late twentieth century, it has been seen that the progress of information technology is changing everyday business. Advents such as telecommunications, for example, are increasing the speed of work, facilitating communication between people and changing to the way of doing business. From the moment at which transform organizational processes, information technologies also bring changes to the dynamics of the work. Thus, both the job security as employability, which is a job for life, are concepts that are becoming distant from everyday human. Emerge a new concept, the workability, which involves the individual's ability to generate income without necessarily having an employment relationship. In this sense, the worker becomes a production unit itself, from the administration of their own abilities and skills, acting as an entrepreneur. Given this, the purpose of this article is to show that the concepts of workability and entrepreneurship go together, and this concept dependent on that. The construction of this article was carried out bibliographic research with the issues involved. This study is structured as follows: in the first part, is carried out a review of existing changes in the current world and the implications for entrepreneurship. Then the concepts of entrepreneurship, workability and employability are explained. Then the methodology is presented, followed by the results and discussion. Finally, this study is closed through the final considerations.

  3. Distributed multiple path routing in complex networks

    Science.gov (United States)

    Chen, Guang; Wang, San-Xiu; Wu, Ling-Wei; Mei, Pan; Yang, Xu-Hua; Wen, Guang-Hui

    2016-12-01

    Routing in complex transmission networks is an important problem that has garnered extensive research interest in the recent years. In this paper, we propose a novel routing strategy called the distributed multiple path (DMP) routing strategy. For each of the O-D node pairs in a given network, the DMP routing strategy computes and stores multiple short-length paths that overlap less with each other in advance. And during the transmission stage, it rapidly selects an actual routing path which provides low transmission cost from the pre-computed paths for each transmission task, according to the real-time network transmission status information. Computer simulation results obtained for the lattice, ER random, and scale-free networks indicate that the strategy can significantly improve the anti-congestion ability of transmission networks, as well as provide favorable routing robustness against partial network failures.

  4. Local-time representation of path integrals.

    Science.gov (United States)

    Jizba, Petr; Zatloukal, Václav

    2015-12-01

    We derive a local-time path-integral representation for a generic one-dimensional time-independent system. In particular, we show how to rephrase the matrix elements of the Bloch density matrix as a path integral over x-dependent local-time profiles. The latter quantify the time that the sample paths x(t) in the Feynman path integral spend in the vicinity of an arbitrary point x. Generalization of the local-time representation that includes arbitrary functionals of the local time is also provided. We argue that the results obtained represent a powerful alternative to the traditional Feynman-Kac formula, particularly in the high- and low-temperature regimes. To illustrate this point, we apply our local-time representation to analyze the asymptotic behavior of the Bloch density matrix at low temperatures. Further salient issues, such as connections with the Sturm-Liouville theory and the Rayleigh-Ritz variational principle, are also discussed.

  5. Riemann Curvature Tensor and Closed Geodesic Paths

    Science.gov (United States)

    Morganstern, Ralph E.

    1977-01-01

    Demonstrates erroneous results obtained if change in a vector under parallel transport about a closed path in Riemannian spacetime is made in a complete circuit rather than just half a circuit. (Author/SL)

  6. Non-classical paths in interference experiments

    CERN Document Server

    Sawant, Rahul; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-01-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well known text books in quantum mechanics implicitly and/or explicitly use this assumption which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in quantum interference experiments which provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  7. Nonclassical Paths in Quantum Interference Experiments

    Science.gov (United States)

    Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-09-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well-known text books in quantum mechanics implicitly and/or explicitly use this assumption that is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from nonclassical paths in quantum interference experiments that provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these nonclassical paths is difficult to present. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  8. Path Integral Approach to Atomic Collisions

    Science.gov (United States)

    Harris, Allison

    2016-09-01

    The Path Integral technique is an alternative formulation of quantum mechanics that is based on a Lagrangian approach. In its exact form, it is completely equivalent to the Hamiltonian-based Schrödinger equation approach. Developed by Feynman in the 1940's, following inspiration from Dirac, the path integral approach has been widely used in high energy physics, quantum field theory, and statistical mechanics. However, only in limited cases has the path integral approach been applied to quantum mechanical few-body scattering. We present a theoretical and computational development of the path integral method for use in the study of atomic collisions. Preliminary results are presented for some simple systems. Ultimately, this approach will be applied to few-body ion-atom collisions. Work supported by NSF grant PHY-1505217.

  9. Predicting missing links via significant paths

    CERN Document Server

    Zhu, Xuzhen; Cai, Shimin; Huang, Junming; Zhou, Tao

    2014-01-01

    Link prediction plays an important role in understanding intrinsic evolving mechanisms of networks. With the belief that the likelihood of the existence of a link between two nodes is strongly related with their similarity, many methods have been proposed to calculate node similarity based on node attributes and/or topological structures. Among a large variety of methods that take into account paths connecting the target pair of nodes, most of which neglect the heterogeneity of those paths. Our hypothesis is that a path consisting of small-degree nodes provides a strong evidence of similarity between two ends, accordingly, we propose a so-called sig- nificant path index in this Letter to leverage intermediate nodes' degrees in similarity calculation. Empirical experiments on twelve disparate real networks demonstrate that the proposed index outperforms the mainstream link prediction baselines.

  10. Aircraft Path Planning under Adverse Weather Conditions

    Directory of Open Access Journals (Sweden)

    Xie Z.

    2016-01-01

    Full Text Available In recent years, flight safety is still one of the main issues for all airlines. En route civil airplanes may encounter adverse weather conditions. Some fatal airplane accidents happened because of the weather disturbance. Moreover, we should also design path to avoid the prohibited area. Therefore a good path planning algorithm plays an increasingly important role in air traffic management. An efficient path planning algorithm can help the plane to avoid severe weather conditions, restricted areas and moving obstacles to ensure the safety of the cabin crews and passengers. Here, we build our algorithm based on the A* search algorithm. Moreover, our algorithm can also find the path with least energy costs. As a result, our algorithm can improve the safety operation of the airplanes and reduce the workload of pilots and air traffic controllers.

  11. Path integration in relativistic quantum mechanics

    CERN Document Server

    Redmount, I H; Redmount, Ian H.; Suen, Wai-Mo

    1993-01-01

    The simple physics of a free particle reveals important features of the path-integral formulation of relativistic quantum theories. The exact quantum-mechanical propagator is calculated here for a particle described by the simple relativistic action proportional to its proper time. This propagator is nonvanishing outside the light cone, implying that spacelike trajectories must be included in the path integral. The propagator matches the WKB approximation to the corresponding configuration-space path integral far from the light cone; outside the light cone that approximation consists of the contribution from a single spacelike geodesic. This propagator also has the unusual property that its short-time limit does not coincide with the WKB approximation, making the construction of a concrete skeletonized version of the path integral more complicated than in nonrelativistic theory.

  12. Path dependence and independent utility regulation

    DEFF Research Database (Denmark)

    Ibsen, Christian Lyhne; Skovgaard Poulsen, Lauge

    2007-01-01

    The establishment of the Danish independent regulatory authorities for the energy and telecommunications sectors was based upon EU directives as part of their liberalisation process. Following the concepts of transaction costs and path dependency this article analyses differences in independence...

  13. Northern Pintail - Flight Path Telemetry [ds117

    Data.gov (United States)

    California Department of Resources — North-south flight paths of radio-tagged female northern pintails were monitored in a section of Highway 152 near Los Banos, California during 4 and 11 November and...

  14. Path integral distance for data interpretation

    CERN Document Server

    Volchenkov, D

    2015-01-01

    The process of data interpretation is always based on the implicit introduction of equivalence relations on the set of walks over the database. Every equivalence relation on the set of walks specifies a Markov chain describing the transitions of a discrete time random walk. In order to geometrize and interpret the data, we propose the new distance between data units defined as a "Feynman path integral", in which all possible paths between any two nodes in a graph model of the data are taken into account, although some paths are more preferable than others. Such a path integral distance approach to the analysis of databases has proven its efficiency and success, especially on multivariate strongly correlated data where other methods fail to detect structural components (urban planning, historical language phylogenies, music, street fashion traits analysis, etc. ). We believe that it would become an invaluable tool for the intelligent complexity reduction and big data interpretation.

  15. Modeling DNA Dynamics by Path Integrals

    CERN Document Server

    Zoli, Marco

    2013-01-01

    Complementary strands in DNA double helix show temporary fluctuational openings which are essential to biological functions such as transcription and replication of the genetic information. Such large amplitude fluctuations, known as the breathing of DNA, are generally localized and, microscopically, are due to the breaking of the hydrogen bonds linking the base pairs (\\emph{bps}). I apply imaginary time path integral techniques to a mesoscopic Hamiltonian which accounts for the helicoidal geometry of a short circular DNA molecule. The \\emph{bps} displacements with respect to the ground state are interpreted as time dependent paths whose amplitudes are consistent with the model potential for the hydrogen bonds. The portion of the paths configuration space contributing to the partition function is determined by selecting the ensemble of paths which fulfill the second law of thermodynamics. Computations of the thermodynamics in the denaturation range show the energetic advantage for the equilibrium helicoidal g...

  16. Noncommutative integrability, paths and quasi-determinants

    CERN Document Server

    Di Francesco, Philippe

    2010-01-01

    In previous work, we showed that the solution of certain systems of discrete integrable equations, notably $Q$ and $T$-systems, is given in terms of partition functions of positively weighted paths, thereby proving the positive Laurent phenomenon of Fomin and Zelevinsky for these cases. This method of solution is amenable to generalization to non-commutative weighted paths. Under certain circumstances, these describe solutions of discrete evolution equations in non-commutative variables: Examples are the corresponding quantum cluster algebras [BZ], the Kontsevich evolution [DFK09b] and the $T$-systems themselves [DFK09a]. In this paper, we formulate certain non-commutative integrable evolutions by considering paths with non-commutative weights, together with an evolution of the weights that reduces to cluster algebra mutations in the commutative limit. The general weights are expressed as Laurent monomials of quasi-determinants of path partition functions, allowing for a non-commutative version of the positiv...

  17. Building a path in cell biology.

    Science.gov (United States)

    Voeltz, Gia; Cheeseman, Iain

    2012-11-01

    Setting up a new lab is an exciting but challenging prospect. We discuss our experiences in finding a path to tackle some of the key current questions in cell biology and the hurdles that we have encountered along the way.

  18. A chemist building paths to cell biology.

    Science.gov (United States)

    Weibel, Douglas B

    2013-11-01

    Galileo is reported to have stated, "Measure what is measurable and make measurable what is not so." My group's trajectory in cell biology has closely followed this philosophy, although it took some searching to find this path.

  19. Feasible Path Planning for Autonomous Vehicles

    Directory of Open Access Journals (Sweden)

    Vu Trieu Minh

    2014-01-01

    Full Text Available The objective of this paper is to find feasible path planning algorithms for nonholonomic vehicles including flatness, polynomial, and symmetric polynomial trajectories subject to the real vehicle dynamical constraints. Performances of these path planning methods are simulated and compared to evaluate the more realistic and smoother generated trajectories. Results show that the symmetric polynomial algorithm provides the smoothest trajectory. Therefore, this algorithm is recommended for the development of an automatic control for autonomous vehicles.

  20. Competition for shortest paths on sparse graphs.

    Science.gov (United States)

    Yeung, Chi Ho; Saad, David

    2012-05-18

    Optimal paths connecting randomly selected network nodes and fixed routers are studied analytically in the presence of a nonlinear overlap cost that penalizes congestion. Routing becomes more difficult as the number of selected nodes increases and exhibits ergodicity breaking in the case of multiple routers. The ground state of such systems reveals nonmonotonic complex behaviors in average path length and algorithmic convergence, depending on the network topology, and densities of communicating nodes and routers. A distributed linearly scalable routing algorithm is also devised.

  1. Dressed coordinates: The path-integral approach

    Science.gov (United States)

    Casana, R.; Flores-Hidalgo, G.; Pimentel, B. M.

    2007-02-01

    The recently introduced dressed coordinates are studied in the path-integral approach. These coordinates are defined in the context of a harmonic oscillator linearly coupled to massless scalar field and it is shown that in this model the dressed coordinates appear as a coordinate transformation preserving the path-integral functional measure. The analysis also generalizes the sum rules established in a previous work.

  2. Create three distinct career paths for innovators.

    Science.gov (United States)

    O'Connor, Gina Colarelli; Corbett, Andrew; Pierantozzi, Ron

    2009-12-01

    Large companies say they Create Three Distinct want to be Career Paths for Innovators innovative, but they fundamentally mismanage their talent. Expecting innovators to grow along with their projects-from discovery to incubation to acceleration--sets them up to fail. Most people excel at one of the phases, not all three. By allowing innovation employees to develop career paths suited to their strengths, companies will create a sustainable innovation function.

  3. The Feynman Path Goes Monte Carlo

    OpenAIRE

    Sauer, Tilman

    2001-01-01

    Path integral Monte Carlo (PIMC) simulations have become an important tool for the investigation of the statistical mechanics of quantum systems. I discuss some of the history of applying the Monte Carlo method to non-relativistic quantum systems in path-integral representation. The principle feasibility of the method was well established by the early eighties, a number of algorithmic improvements have been introduced in the last two decades.

  4. A novel method for robot path planning

    Institute of Scientific and Technical Information of China (English)

    CAI Qiang; LI Hai-sheng; YANG Qin; LI Ji-gang

    2009-01-01

    Path planning is one of the most important problems in the design of a mobile robot. A novel approach called generalized Voronoi diagrams (GVD) may deal with this matter. First, a method was introduced to normalize the obstacles and present efficient techniques for generating GVDs. Then a best path searching algorithm was presented. Examples implemented were given to indicate the availability of the mentioned algorithms. The approaches in this paper can also be used in applications including visualization, spatial data manipulation, etc.

  5. A Path Algorithm for Constrained Estimation.

    Science.gov (United States)

    Zhou, Hua; Lange, Kenneth

    2013-01-01

    Many least-square problems involve affine equality and inequality constraints. Although there are a variety of methods for solving such problems, most statisticians find constrained estimation challenging. The current article proposes a new path-following algorithm for quadratic programming that replaces hard constraints by what are called exact penalties. Similar penalties arise in l1 regularization in model selection. In the regularization setting, penalties encapsulate prior knowledge, and penalized parameter estimates represent a trade-off between the observed data and the prior knowledge. Classical penalty methods of optimization, such as the quadratic penalty method, solve a sequence of unconstrained problems that put greater and greater stress on meeting the constraints. In the limit as the penalty constant tends to ∞, one recovers the constrained solution. In the exact penalty method, squared penalties!are replaced by absolute value penalties, and the solution is recovered for a finite value of the penalty constant. The exact path-following method starts at the unconstrained solution and follows the solution path as the penalty constant increases. In the process, the solution path hits, slides along, and exits from the various constraints. Path following in Lasso penalized regression, in contrast, starts with a large value of the penalty constant and works its way downward. In both settings, inspection of the entire solution path is revealing. Just as with the Lasso and generalized Lasso, it is possible to plot the effective degrees of freedom along the solution path. For a strictly convex quadratic program, the exact penalty algorithm can be framed entirely in terms of the sweep operator of regression analysis. A few well-chosen examples illustrate the mechanics and potential of path following. This article has supplementary materials available online.

  6. Decomposing Path : The Nanosyntax of Directional Expressions

    OpenAIRE

    Pantcheva, Marina Blagoeva

    2011-01-01

    In my thesis, I investigate directional expressions cross-linguistically. I examine the morpho-syntactic structure of expressions of Goal (to the house), Source (from the house), Route (through the house), non-transitional paths (towards the house) and, finally, delimited paths (up to the house). I conclude that all these types of directional expressions are of different syntactic complexity. Precisely, Source expressions (from) are formed on the basis of Goal expressions (to) and Route expr...

  7. Dynamic Shortest Path Monitoring in Spatial Networks

    Institute of Scientific and Technical Information of China (English)

    Shuo Shang; Lisi Chen; Zhe-Wei Wei; Dan-Huai Guo; Ji-Rong Wen

    2016-01-01

    With the increasing availability of real-time traffic information, dynamic spatial networks are pervasive nowa-days and path planning in dynamic spatial networks becomes an important issue. In this light, we propose and investigate a novel problem of dynamically monitoring shortest paths in spatial networks (DSPM query). When a traveler aims to a des-tination, his/her shortest path to the destination may change due to two reasons: 1) the travel costs of some edges have been updated and 2) the traveler deviates from the pre-planned path. Our target is to accelerate the shortest path computing in dynamic spatial networks, and we believe that this study may be useful in many mobile applications, such as route planning and recommendation, car navigation and tracking, and location-based services in general. This problem is challenging due to two reasons: 1) how to maintain and reuse the existing computation results to accelerate the following computations, and 2) how to prune the search space effectively. To overcome these challenges, filter-and-refinement paradigm is adopted. We maintain an expansion tree and define a pair of upper and lower bounds to prune the search space. A series of optimization techniques are developed to accelerate the shortest path computing. The performance of the developed methods is studied in extensive experiments based on real spatial data.

  8. *-Regular Leavitt Path Algebras of Arbitrary Graphs

    Institute of Scientific and Technical Information of China (English)

    Gonzalo ARANDA PINO; Kulumani RANGASWAMY; Lia VA(S)

    2012-01-01

    If K is a field with involution and E an arbitrary graph,the involution from K naturally induces an involution of the Leavitt path algebra LK(E).We show that the involution on LK(E) is proper if the involution on K is positive-definite,even in the case when the graph E is not necessarily finite or row-finite.It has been shown that the Leavitt path algebra LK(E) is regular if and only if E is acyclic.We give necessary and sufficient conditions for LK(E) to be *-regular (i.e.,regular with proper involution).This characterization of *-regularity of a Leavitt path algebra is given in terms of an algebraic property of K,not just a graph-theoretic property of E.This differs from the.known characterizations of various other algebraic properties of a Leavitt path algebra in terms of graphtheoretic properties of E alone.As a corollary,we show that Handelman's conjecture (stating that every *-regular ring is unit-regular) holds for Leavitt path algebras.Moreover,its generalized version for rings with local units also continues to hold for Leavitt path algebras over arbitrary graphs.

  9. Redesigning Schools to Reach Every Student with Excellent Teachers: Summary of Teacher Career Paths

    Science.gov (United States)

    Public Impact, 2012

    2012-01-01

    These career paths match Public Impact's school models that use job redesign and technology to extend the reach of excellent teachers to more students, for more pay, within budget. Most models create new roles and teams enabling all teachers and staff to develop and contribute to excellence. In "reach-extended roles," excellent teachers…

  10. Impairment-Aware Routing in Translucent Spectrum-Sliced Elastic Optical Path Networks

    NARCIS (Netherlands)

    Yang, S.; Kuipers, F.

    2012-01-01

    Spectrum-sliced elastic optical path (SLICE) technology offers a more flexible bandwidth allocation in optical networks than wavelength division multiplexing. It allows different connections to be served via different modulation formats. However, as with any optical network, the optical signal may b

  11. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  12. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-02-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  13. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1999-10-01

    The activities of the AGTSR Program during this reporting period are described in this quarterly report. The report text is divided into discussions on Membership, Administration, Technology Transfer (Workshop/Education) and Research. Items worthy of note are highlighted below with additional detail following in the text of the report.

  14. Parallel path planning in unknown terrains

    Science.gov (United States)

    Prassler, Erwin A.; Milios, Evangelos E.

    1991-03-01

    We present a parallel processing approach to path planning in unknown terrains which combines map-based and sensor-based techniques into a real-time capable navigation system. The method is based on massively parallel computations in a grid of simple processing elements denoted as cells. In the course of a relaxation process a potential distribution is created in the grid which exhibits a monotonous slope from a start cell to the cell corresponding to the robot''s goal position. A shortest path is determined by means of a gradient descent criterion which settles on the steepest descent in the potential distribution. Like high-level path planning algorithms our approach is capable of planning shortest paths through an arbitrarily cluttered large-scale terrain on the basis of its current internal map. Sequentially implemented its complexity is in the order of efficient classical path planning algorithms. Unlike these algorithms however the method is also highly responsive to new obstacles encountered in the terrain. By continuing the planning process during the robot''s locomotion information about previously unknown obstacles immediately affects further path planning without a need to interrupt the ongoing planning process. New obstacles cause distortions of the potential distribution which let the robot find proper detours. By ensuring a monotonous slope in the overall distribution we avoid local minimum effects which may trap a robot in the proximity of an obstacle configuration before it has reached its goal. 1 Until the recent past research on path planning in the presence of obstacles can be assigned to two major categories: map-based high-level planning approaches and sensor-based low-level conLrol approaches. In work such as 12 path planning is treated as a high-level planning task. Assuming that an (accnrae) precompiled map of the terrain is available high-level path planners provide paths which guarantee a collision-free locomotion through an arbitrary

  15. Reliability Analysis of Random Vibration Transmission Path Systems

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2017-01-01

    Full Text Available The vibration transmission path systems are generally composed of the vibration source, the vibration transfer path, and the vibration receiving structure. The transfer path is the medium of the vibration transmission. Moreover, the randomness of transfer path influences the transfer reliability greatly. In this paper, based on the matrix calculus, the generalized second moment technique, and the stochastic finite element theory, the effective approach for the transfer reliability of vibration transfer path systems was provided. The transfer reliability of vibration transfer path system with uncertain path parameters including path mass and path stiffness was analyzed theoretically and computed numerically, and the correlated mathematical expressions were derived. Thus, it provides the theoretical foundation for the dynamic design of vibration systems in practical project, so that most random path parameters can be considered to solve the random problems for vibration transfer path systems, which can avoid the system resonance failure.

  16. HYDRAULIC CHARACTERIZATIONS OF TORTUOUS FLOW IN PATH DRIP IRRIGATION EMITTER

    Institute of Scientific and Technical Information of China (English)

    LI Yun-kai; YANG Pei-ling; REN Shu-mei; XU Ting-wu

    2006-01-01

    At present, the tortuous emitter has the most advanced performances in drip irrigation. But the theories and methods for designing its flow path have been strictly confidential and the researches on the function of practical guidance have seldom been published. Seven types of most representative tortuous emitting-pipes currently used in agricultural irrigation regions of China were chosen for investigating the geometric parameters of the flow path by means of combining high-precision microscope and AutoCAD technology. By the measurement platform developed by the authors for hydraulic performances of emitters, the free discharge rates from the 7 types of emitters were measured at 9 pressure levels of 1.5 m, 3.0 m, 5.0 m, 7.0 m, 9.0 m, 10.0 m, 11.0 m, 13.0 m and 15.0 m. Then the discharge-pressure relationship, manufacturing variation coefficient, average velocity on the cross-section of flow path and the critical Reynolds number for the flow regime transformation within the paths were analyzed in detail. The results show that both pressure-ascending work pattern and pressure-descending work pattern have some impacts on the discharge rates of tortuous emitters, but the impact level is not significant. The target pressure could be approached by repetitive applications of the two work patterns during pressure regulation. The operation under low pressures has some impacts on the hydraulic performances of emitters, but the impact level is also not significant. The classical model of the discharge-pressure relationship is suitable for the pressure range of 1.5 m -15.0 m. The Reynolds number for fluids within the 7 types of tortuous emitters ranges from =105 to =930. The critical Reynolds number for the flow regime transformation is smaller than that for the routine dimension flow path. The variation coefficient of emitter discharge rates is slightly fluctuating around a certain value within the whole pressure range.

  17. Comparison of flux measurement by open-path and close-path eddy covariance systems

    Institute of Scientific and Technical Information of China (English)

    SONG; Xia; YU; Guirui; LIU; Yunfen; SUN; Xiaomin; REN; Chua

    2005-01-01

    For flux measurement, the eddy covariance technique supplies a possibility to directly measure the exchange between vegetation and atmosphere; and there are two kinds of eddy covariance systems, open-path and close-path systems. For the system error, it may result in difference of flux measurements by two systems. Therefore, it is necessary to compare the measured results from them. ChinaFLUX covers of eight sites applied the micrometeorological method, in which Changbai Mountains (CBS) and Qianyanzhou (QYZ) carried out open-path eddy covariance (OPEC) and close-path eddy covariance (CPEC) measurements synchronously.In this paper the data sets of CBS and QYZ were employed. The delay time of close-path analyzer to the open-path analyzer was calculated; the spectra and cospectra of time-series data of OPEC and CPEC were analyzed; the open-path flux measurement was used as a standard comparison, the close-path flux measurement results were evaluated. The results show that, at two sites the delay time of CO2 density for close-path analyzer was about 7.0-8.0 s, H2O density about 8.0-9.0 s; the spectrum from the open-path, close-path and 3D sonic anemometer was consistent with the expected -2/3 slope (log-log plot), and the cospectra showed the expected slope of -4/3 in the internal subrange; the CO2 flux measured by the close-path sensor was about 84% of that of open-path measurement at QYZ, about 80% at CBS, and the latent heat flux was balanced for two systems at QYZ, 86% at CBS. From the flux difference between open-path and close-path analyzers, it could be inferred that the attenuation of turbulent fluctuations in flow through tube of CPEC affected H2O flux more significantly than CO2 flux. The gap between two systems was bigger at CBS than at QYZ; the diurnal variation in CO2 flux of two measurement systems was very consistent.

  18. SHP: Smooth Hypocycloidal Paths with Collision-Free and Decoupled Multi-Robot Path Planning

    Directory of Open Access Journals (Sweden)

    Abhijeet Ravankar

    2016-06-01

    Full Text Available Generating smooth and continuous paths for robots with collision avoidance, which avoid sharp turns, is an important problem in the context of autonomous robot navigation. This paper presents novel smooth hypocycloidal paths (SHP for robot motion. It is integrated with collision-free and decoupled multi-robot path planning. An SHP diffuses (i.e., moves points along segments the points of sharp turns in the global path of the map into nodes, which are used to generate smooth hypocycloidal curves that maintain a safe clearance in relation to the obstacles. These nodes are also used as safe points of retreat to avoid collision with other robots. The novel contributions of this work are as follows: (1 The proposed work is the first use of hypocycloid geometry to produce smooth and continuous paths for robot motion. A mathematical analysis of SHP generation in various scenarios is discussed. (2 The proposed work is also the first to consider the case of smooth and collision-free path generation for a load carrying robot. (3 Traditionally, path smoothing and collision avoidance have been addressed as separate problems. This work proposes integrated and decoupled collision-free multi-robot path planning. ‵Node caching‵ is proposed to improve efficiency. A decoupled approach with local communication enables the paths of robots to be dynamically changed. (4 A novel ‵multi-robot map update‵ in case of dynamic obstacles in the map is proposed, such that robots update other robots about the positions of dynamic obstacles in the map. A timestamp feature ensures that all the robots have the most updated map. Comparison between SHP and other path smoothing techniques and experimental results in real environments confirm that SHP can generate smooth paths for robots and avoid collision with other robots through local communication.

  19. A Split-Path Schema-Based RFID Data Storage Model in Supply Chain Management

    Directory of Open Access Journals (Sweden)

    Jianfeng Zhang

    2013-05-01

    Full Text Available In modern supply chain management systems, Radio Frequency IDentification (RFID technology has become an indispensable sensor technology and massive RFID data sets are expected to become commonplace. More and more space and time are needed to store and process such huge amounts of RFID data, and there is an increasing realization that the existing approaches cannot satisfy the requirements of RFID data management. In this paper, we present a split-path schema-based RFID data storage model. With a data separation mechanism, the massive RFID data produced in supply chain management systems can be stored and processed more efficiently. Then a tree structure-based path splitting approach is proposed to intelligently and automatically split the movement paths of products . Furthermore, based on the proposed new storage model, we design the relational schema to store the path information and time information of tags, and some typical query templates and SQL statements are defined. Finally, we conduct various experiments to measure the effect and performance of our model and demonstrate that it performs significantly better than the baseline approach in both the data expression and path-oriented RFID data query performance.

  20. Path Integral Techniques in Conformal Field Theory

    CERN Document Server

    Van Tonder, A J

    2004-01-01

    We present the theory of a two-dimensional conformal scalar field using path integral techniques. We derive the conformal anomaly using an adaptation of the method of Fujikawa, and compare the result with a derivation based on a Pauli-Villars measure, where the anomaly is shifted from the path integral measure to the energy-momentum trace. In the path integral approach the energy-momentum is a true coordinate-invariant tensor quantity, and we explain how it is related to the corresponding non-tensor object arising in the operator approach, obtaining an intuitive explanation within the context of the path integral approach for the anomalous transformation law and anomalous Ward identities of the latter. After carefully calculating nontrivial contact terms arising in certain energy-momentum products, we use these to provide a simple consistency check confirming the change of variables formula for the path integral and to review the relationship between the conformal anomaly and the energy-momentum two-point fun...

  1. Accurate free energy calculation along optimized paths.

    Science.gov (United States)

    Chen, Changjun; Xiao, Yi

    2010-05-01

    The path-based methods of free energy calculation, such as thermodynamic integration and free energy perturbation, are simple in theory, but difficult in practice because in most cases smooth paths do not exist, especially for large molecules. In this article, we present a novel method to build the transition path of a peptide. We use harmonic potentials to restrain its nonhydrogen atom dihedrals in the initial state and set the equilibrium angles of the potentials as those in the final state. Through a series of steps of geometrical optimization, we can construct a smooth and short path from the initial state to the final state. This path can be used to calculate free energy difference. To validate this method, we apply it to a small 10-ALA peptide and find that the calculated free energy changes in helix-helix and helix-hairpin transitions are both self-convergent and cross-convergent. We also calculate the free energy differences between different stable states of beta-hairpin trpzip2, and the results show that this method is more efficient than the conventional molecular dynamics method in accurate free energy calculation.

  2. Default Path and Dedicated Path: A New Approach to Realize IP Directly Over WDM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Combining IP and WDM is an attractive direction for research. Instead the point to point linking method, this paper proposes a new approach to realize IP directly over WDM, called DPDP (default path and dedicated path), presents a conceivable architecture in detail and explains its working procedure. A lot of problems related with this design are also discussed.

  3. 14 CFR 23.61 - Takeoff flight path.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff flight path. 23.61 Section 23.61... flight path. For each commuter category airplane, the takeoff flight path must be determined as follows: (a) The takeoff flight path begins 35 feet above the takeoff surface at the end of the...

  4. Path Analysis: A Link between Family Theory and Reseach.

    Science.gov (United States)

    Rank, Mark R.; Sabatelli, Ronald M.

    This paper discusses path analysis and the applicability of this methodology to the field of family studies. The statistical assumptions made in path analysis are presented along with a description of the two types of models within path analysis, i.e., recursive and non-recursive. Methods of calculating in the path model and the advantages of…

  5. Stealth-Based Path Planning using Corridor Maps

    NARCIS (Netherlands)

    Geraerts, R.J.|info:eu-repo/dai/nl/304830291; Schager, E.

    2010-01-01

    A relatively new area within the field of path planning deals with computing a stealthy path for a character moving in a virtual environment. Besides efficiently obtaining a path that is collision-free, short and smooth, the added difficulty is that the path must have little or no exposure to observ

  6. An Adaptive Path Planning Algorithm for Cooperating Unmanned Air Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, C.T.; Roberts, R.S.

    2000-09-12

    An adaptive path planning algorithm is presented for cooperating Unmanned Air Vehicles (UAVs) that are used to deploy and operate land-based sensor networks. The algorithm employs a global cost function to generate paths for the UAVs, and adapts the paths to exceptions that might occur. Examples are provided of the paths and adaptation.

  7. In-Space Manufacturing: Pioneering a Sustainable Path to Mars

    Science.gov (United States)

    Werkheiser, Niki

    2015-01-01

    In order to provide meaningful impacts to exploration technology needs, the In-Space Manufacturing (ISM) Initiative must influence exploration systems design now. In-space manufacturing offers: dramatic paradigm shift in the development and creation of space architectures; efficiency gain and risk reduction for low Earth orbit and deep space exploration; and "pioneering" approach to maintenance, repair, and logistics leading to sustainable, affordable supply chain model. In order to develop application-based capabilities in time to support NASA budget and schedule, ISM must be able to leverage the significant commercial developments, which requires innovative, agile collaborative mechanisms (contracts, challenges, SBIR's, etc.); and NASA-unique investments to focus primarily on adapting the technologies and processes to the microgravity environment. We must do the foundational work - it is the critical path for taking these technologies from lab curiosities to institutionalized capabilities: characterize, certify, institutionalize, design for Additive Manufacturing (AM). Ideally, International Space Station (ISS) U.S. lab rack or partial rack space should be identified for in-space manufacturing utilization in order to continue technology development of a suite of capabilities required for exploration missions, as well as commercialization on ISS.

  8. Self-calibrating common-path interferometry.

    Science.gov (United States)

    Porras-Aguilar, Rosario; Falaggis, Konstantinos; Ramirez-San-Juan, Julio C; Ramos-Garcia, Ruben

    2015-02-09

    A quantitative phase measuring technique is presented that estimates the object phase from a series of phase shifted interferograms that are obtained in a common-path configuration with unknown phase shifts. The derived random phase shifting algorithm for common-path interferometers is based on the Generalized Phase Contrast theory [pl. Opt.40(2), 268 (2001)10.1063/1.1404846], which accounts for the particular image formation and includes effects that are not present in two-beam interferometry. It is shown experimentally that this technique can be used within common-path configurations employing nonlinear liquid crystal materials as self-induced phase filters for quantitative phase imaging without the need of phase shift calibrations. The advantages of such liquid crystal elements compared to spatial light modulator based solutions are given by the cost-effectiveness, self-alignment, and the generation of diminutive dimensions of the phase filter size, giving unique performance advantages.

  9. The path exchange method for hybrid LCA.

    Science.gov (United States)

    Lenzen, Manfred; Crawford, Robert

    2009-11-01

    Hybrid techniques for Life-Cycle Assessment (LCA) provide a way of combining the accuracy of process analysis and the completeness of input-output analysis. A number of methods have been suggested to implement a hybrid LCA in practice, with the main challenge being the integration of specific process data with an overarching input-output system. In this work we present a new hybrid LCA method which works at the finest input-output level of detail: structural paths. This new Path Exchange method avoids double-counting and system disturbance just as previous hybrid LCA methods, but instead of a large LCA database it requires only a minimum of external information on those structural paths that are to be represented by process data.

  10. Approximate shortest homotopic paths in weighted regions

    KAUST Repository

    Cheng, Siuwing

    2012-02-01

    A path P between two points s and t in a polygonal subdivision T with obstacles and weighted regions defines a class of paths that can be deformed to P without passing over any obstacle. We present the first algorithm that, given P and a relative error tolerance ε (0, 1), computes a path from this class with cost at most 1 + ε times the optimum. The running time is O(h 3/ε 2kn polylog (k,n,1/ε)), where k is the number of segments in P and h and n are the numbers of obstacles and vertices in T, respectively. The constant in the running time of our algorithm depends on some geometric parameters and the ratio of the maximum region weight to the minimum region weight. © 2012 World Scientific Publishing Company.

  11. Approximate Shortest Homotopic Paths in Weighted Regions

    KAUST Repository

    Cheng, Siu-Wing

    2010-01-01

    Let P be a path between two points s and t in a polygonal subdivision T with obstacles and weighted regions. Given a relative error tolerance ε ∈(0,1), we present the first algorithm to compute a path between s and t that can be deformed to P without passing over any obstacle and the path cost is within a factor 1 + ε of the optimum. The running time is O(h 3/ε2 kn polylog(k, n, 1/ε)), where k is the number of segments in P and h and n are the numbers of obstacles and vertices in T, respectively. The constant in the running time of our algorithm depends on some geometric parameters and the ratio of the maximum region weight to the minimum region weight. © 2010 Springer-Verlag.

  12. Quickest Paths for Different Network Router Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Rao, N.S.V.; Grimmell, W.C.; Radhakrishnan, S.; Bang, Y.C.

    2000-06-01

    The quickest path problem deals with the transmission of a message of size {sigma} from a source to a destination with the minimum end-to-end delay over a network with bandwidth and delay constraints on the links. The authors consider four basic modes and two variations for the message delivery at the nodes reflecting the mechanisms such as circuit switching, Internet protocol, and their combinations. For each of the first three modes, they present O(m{sup 2} + mn log n) time algorithm to compute the quickest path for a given message size {sigma}. For the last mode, the quickest path can be computed in O(m + n log n) time.

  13. Quickest Paths in Simulations of Pedestrians

    CERN Document Server

    Kretz, Tobias; Hengst, Stefan; Kautzsch, Lukas; Pohlmann, Andrej; Vortisch, Peter

    2011-01-01

    This contribution proposes a method to make agents in a microscopic simulation of pedestrian traffic walk approximately along a path of estimated minimal remaining travel time to their destination. Usually models of pedestrian dynamics are (implicitly) built on the assumption that pedestrians walk along the shortest path. Model elements formulated to make pedestrians locally avoid collisions and intrusion into personal space do not produce motion on quickest paths. Therefore a special model element is needed, if one wants to model and simulate pedestrians for whom travel time matters most (e.g. travelers in a station hall who are late for a train). Here such a model element is proposed, discussed and used within the Social Force Model.

  14. Shortest Path Computation with No Information Leakage

    CERN Document Server

    Mouratidis, Kyriakos

    2012-01-01

    Shortest path computation is one of the most common queries in location-based services (LBSs). Although particularly useful, such queries raise serious privacy concerns. Exposing to a (potentially untrusted) LBS the client's position and her destination may reveal personal information, such as social habits, health condition, shopping preferences, lifestyle choices, etc. The only existing method for privacy-preserving shortest path computation follows the obfuscation paradigm; it prevents the LBS from inferring the source and destination of the query with a probability higher than a threshold. This implies, however, that the LBS still deduces some information (albeit not exact) about the client's location and her destination. In this paper we aim at strong privacy, where the adversary learns nothing about the shortest path query. We achieve this via established private information retrieval techniques, which we treat as black-box building blocks. Experiments on real, large-scale road networks assess the pract...

  15. Tornado intensity estimated from damage path dimensions.

    Science.gov (United States)

    Elsner, James B; Jagger, Thomas H; Elsner, Ian J

    2014-01-01

    The Newcastle/Moore and El Reno tornadoes of May 2013 are recent reminders of the destructive power of tornadoes. A direct estimate of a tornado's power is difficult and dangerous to get. An indirect estimate on a categorical scale is available from a post-storm survery of the damage. Wind speed bounds are attached to the scale, but the scale is not adequate for analyzing trends in tornado intensity separate from trends in tornado frequency. Here tornado intensity on a continuum is estimated from damage path length and width, which are measured on continuous scales and correlated to the EF rating. The wind speeds on the EF scale are treated as interval censored data and regressed onto the path dimensions and fatalities. The regression model indicates a 25% increase in expected intensity over a threshold intensity of 29 m s(-1) for a 100 km increase in path length and a 17% increase in expected intensity for a one km increase in path width. The model shows a 43% increase in the expected intensity when fatalities are observed controlling for path dimensions. The estimated wind speeds correlate at a level of .77 (.34, .93) [95% confidence interval] with a small sample of wind speeds estimated independently from a doppler radar calibration. The estimated wind speeds allow analyses to be done on the tornado database that are not possible with the categorical scale. The modeled intensities can be used in climatology and in environmental and engineering applications. Research is needed to understand the upward trends in path length and width.

  16. Robust paths to realize nonadiabatic holonomic gates

    Science.gov (United States)

    Xu, G. F.; Zhao, P. Z.; Tong, D. M.; Sjöqvist, Erik

    2017-05-01

    To realize one desired nonadiabatic holonomic gate, various equivalent evolution paths can be chosen. However, in the presence of errors, these paths become inequivalent. In this paper we investigate the difference of these evolution paths in the presence of systematic Rabi-frequency errors and aim to find paths with optimal robustness to realize one-qubit nonadiabatic holonomic gates. We focus on three types of evolution paths in the Λ system: paths belonging to the original two-loop scheme [E. Sjöqvist et al., New J. Phys. 14, 103035 (2012), 10.1088/1367-2630/14/10/103035], the single-loop multiple-pulse scheme [E. Herterich and E. Sjöqvist, Phys. Rev. A 94, 052310 (2016), 10.1103/PhysRevA.94.052310], and the off-resonance single-shot scheme [G. F. Xu et al., Phys. Rev. Lett. 92, 052302 (2015), 10.1103/PhysRevLett.92.052302; E. Sjöqvist, Phys. Lett. A 380, 65 (2016), 10.1016/j.physleta.2015.10.006]. Whereas both the single-loop multiple-pulse and single-shot schemes aim to improve the robustness of the original two-loop scheme by shortening the exposure to decoherence, we find here that the two-loop scheme is more robust to systematic errors in the Rabi frequencies. More importantly, we derive conditions under which the resilience to this kind of error can be optimized, thereby strengthening the robustness of nonadiabatic holonomic gates.

  17. Quantum cosmology based on discrete Feynman paths

    Energy Technology Data Exchange (ETDEWEB)

    Chew, Geoffrey F.

    2002-10-10

    Although the rules for interpreting local quantum theory imply discretization of process, Lorentz covariance is usually regarded as precluding time quantization. Nevertheless a time-discretized quantum representation of redshifting spatially-homogeneous universe may be based on discrete-step Feynman paths carrying causal Lorentz-invariant action--paths that not only propagate the wave function but provide a phenomenologically-promising elementary-particle Hilbert-space basis. In a model under development, local path steps are at Planck scale while, at a much larger ''wave-function scale'', global steps separate successive wave-functions. Wave-function spacetime is but a tiny fraction of path spacetime. Electromagnetic and gravitational actions are ''at a distance'' in Wheeler-Feynman sense while strong (color) and weak (isospin) actions, as well as action of particle motion, are ''local'' in a sense paralleling the action of local field theory. ''Nonmaterial'' path segments and ''trivial events'' collaborate to define energy and gravity. Photons coupled to conserved electric charge enjoy privileged model status among elementary fermions and vector bosons. Although real path parameters provide no immediate meaning for ''measurement'', the phase of the complex wave function allows significance for ''information'' accumulated through ''gentle'' electromagnetic events involving charged matter and ''soft'' photons. Through its soft-photon content the wave function is an ''information reservoir''.

  18. Technology Development Roadmaps - a Systematic Approach to Maturing Needed Technologies

    Energy Technology Data Exchange (ETDEWEB)

    John W. Colllins; Layne Pincock

    2010-07-01

    Abstract. Planning and decision making represent important challenges for all projects. This paper presents the steps needed to assess technical readiness and determine the path forward to mature the technologies required for the Next Generation Nuclear Plant. A Technology Readiness Assessment is used to evaluate the required systems, subsystems, and components (SSC) comprising the desired plant architecture and assess the SSCs against established Technology Readiness Levels (TRLs). A validated TRL baseline is then established for the proposed physical design. Technology Development Roadmaps are generated to define the path forward and focus project research and development and engineering tasks on advancing the technologies to increasing levels of maturity. Tasks include modeling, testing, bench-scale demonstrations, pilot-scale demonstrations, and fully integrated prototype demonstrations. The roadmaps identify precise project objectives and requirements; create a consensus vision of project needs; provide a structured, defensible, decision-based project plan; and, minimize project costs and schedules.

  19. Path planning for everday robotics with SANDROS

    Energy Technology Data Exchange (ETDEWEB)

    Watterberg, P.; Xavier, P. [Sandia National Labs., Albuquerque, NM (United States); Hwang, Y. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)

    1997-02-01

    We discuss the integration of the SANDROS path planner into a general robot simulation and control package with the inclusion of a fast geometry engine for distance calculations. This creates a single system that allows the path to be computed, simulated, and then executed on the physical robot. The architecture and usage procedures are presented. Also, we present examples of its usage in typical environments found in our organization. The resulting system is as easy to use as the general simulation system (which is in common use here) and is fast enough (example problems are solved in seconds) to be used interactively on an everyday basis.

  20. Airway Tree Extraction with Locally Optimal Paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; Sporring, Jon; Pedersen, Jesper Johannes Holst

    2009-01-01

    This paper proposes a method to extract the airway tree from CT images by continually extending the tree with locally optimal paths. This is in contrast to commonly used region growing based approaches that only search the space of the immediate neighbors. The result is a much more robust method...... for tree extraction that can overcome local occlusions. The cost function for obtaining the optimal paths takes into account of an airway probability map as well as measures of airway shape and orientation derived from multi-scale Hessian eigen analysis on the airway probability. Significant improvements...

  1. Field theory a path integral approach

    CERN Document Server

    Das, Ashok

    2006-01-01

    This unique book describes quantum field theory completely within the context of path integrals. With its utility in a variety of fields in physics, the subject matter is primarily developed within the context of quantum mechanics before going into specialized areas.Adding new material keenly requested by readers, this second edition is an important expansion of the popular first edition. Two extra chapters cover path integral quantization of gauge theories and anomalies, and a new section extends the supersymmetry chapter, where singular potentials in supersymmetric systems are described.

  2. Determinants of Box Products of Paths

    CERN Document Server

    Pragel, Daniel

    2011-01-01

    Suppose that G is the graph obtained by taking the box product of a path of length n and a path of length m. Let M be the adjacency matrix of G. If n=m, H.M. Rara showed in 1996 that det(M)=0. We extend this result to allow n and m to be any positive integers, and show that, if gcd(n+1,m+1)>1, then det(M)=0; otherwise, if gcd(n+1,m+1)=1, then det(M)=(-1)^(nm/2).

  3. Vessel tree extraction using locally optimal paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; van Ginneken, Bram; de Bruijne, Marleen

    2010-01-01

    This paper proposes a method to extract vessel trees by continually extending detected branches with locally optimal paths. Our approach uses a cost function from a multi scale vessel enhancement filter. Optimal paths are selected based on rules that take into account the geometric characteristics...... of the vessel tree. Experiments were performed on 10 low dose chest CT scans for which the pulmonary vessel trees were extracted. The proposed method is shown to extract a better connected vessel tree and extract more of the small peripheral vessels in comparison to applying a threshold on the output...

  4. Stability Analysis of Path-vector Routing

    CERN Document Server

    Dimitri, Papadimitriou

    2012-01-01

    Most studies on path-vector routing stability have been conducted empirically by means of ad-hoc analysis of BGP data traces. None of them consider prior specification of an analytic method including the use of stability measurement metrics for the systematic analysis of BGP traces and associated meta-processing for determining the local state of the routing system. In this paper, we define a set of metrics that characterize the local stability properties of path-vector routing such as BGP (Border Gateway Protocol). By means of these stability metrics, we propose a method to analyze the effects of BGP policy- and protocol-induced instability on local routers.

  5. Analysis of Path-vector Routing Stability

    CERN Document Server

    Dimitri, Papadimitriou

    2012-01-01

    Most studies on path-vector routing stability have been conducted empirically by means of ad-hoc analysis of BGP data traces. None of them consider prior specification of an analytic method including the use of stability measurement metrics for the systematic analysis of BGP traces and associated meta-processing for determining the local state of the routing system. In this paper, we define a set of metrics that characterize the local stability properties of path-vector routing such as BGP (Border Gateway Protocol). By means of these stability metrics, we propose a method to analyze the effects of BGP policy- and protocol-induced instability on local routers.

  6. Gas Path Sealing in Turbine Engines

    Science.gov (United States)

    Ludwig, L. P.

    1978-01-01

    A survey of gas path seals is presented with particular attention given to sealing clearance effects on engine component efficiency. The effects on compressor pressure ratio and stall margin are pointed out. Various case-rotor relative displacements, which affect gas path seal clearances, are identified. Forces produced by nonuniform sealing clearances and their effect on rotor stability are discussed qualitatively, and recent work on turbine-blade-tip sealing for high temperature is described. The need for active clearance control and for engine structural analysis is discussed. The functions of the internal-flow system and its seals are reviewed.

  7. Flight Path Recovery System (FPRS) design study

    Energy Technology Data Exchange (ETDEWEB)

    1978-09-01

    The study contained herein presents a design for a Flight Path Recovery System (FPPS) for use in the NURE Program which will be more accurate than systems presently used, provide position location data in digital form suitable for automatic data processing, and provide for flight path recovery in a more economic and operationally suitable manner. The design is based upon the use of presently available hardware and technoloy, and presents little, it any, development risk. In addition, a Flight Test Plan designed to test the FPRS design concept is presented.

  8. Enduring Paths, Crossroads and Intersections: Path-breaking Knowledges in Pede Hollist's So the Path Does Not Die

    Directory of Open Access Journals (Sweden)

    Samuel Alpha Kamara

    2015-09-01

    Full Text Available Among other things, So the Path Does Not Die rekindles age-old themes such as tradition versus change; ethnicity, racism, sexism, and marginal identities; individual and institutional corruption; Diaspora and home; love and sacrifice; civil war and rehabilitation with fresh insights and focus. This article examines these themes in the novel's treatment of Talaba culture and its Musudugu myth.

  9. The FDA critical path initiative and its influence on new drug development.

    Science.gov (United States)

    Woodcock, Janet; Woosley, Raymond

    2008-01-01

    Societal expectations about drug safety and efficacy are rising while productivity in the pharmaceutical industry is falling. In 2004, the US Food and Drug Administration introduced the Critical Path Initiative with the intent of modernizing drug development by incorporating recent scientific advances, such as genomics and advanced imaging technologies, into the process. An important part of the initiative is the use of public-private partnerships and consortia to accomplish the needed research. This article explicates the reasoning behind the Critical Path Initiative and discusses examples of successful consortia.

  10. Magnetic-Phase Dependence of the Spin Carrier Mean Free Path in Graphene Nanoribbons

    Science.gov (United States)

    Li, Jing; Niquet, Yann-Michel; Delerue, Christophe

    2016-06-01

    We show theoretically that the intrinsic (phonon-limited) carrier mobility in graphene nanoribbons is considerably influenced by the presence of spin-polarized edge states. When the coupling between opposite edges switches from antiferromagnetic to ferromagnetic with increasing carrier density, the current becomes spin polarized and the mean free path rises from 10 nm to micrometers. In the ferromagnetic state, the current flows through one majority-spin channel which is ballistic over micrometers and several minority-spin channels with mean free paths as low as 1 nm. These features predicted in technology-relevant conditions could be nicely exploited in spintronic devices.

  11. Survey of Robot 3D Path Planning Algorithms

    OpenAIRE

    Liang Yang; Juntong Qi; Dalei Song; Jizhong Xiao; Jianda Han; Yong Xia

    2016-01-01

    Robot 3D (three-dimension) path planning targets for finding an optimal and collision-free path in a 3D workspace while taking into account kinematic constraints (including geometric, physical, and temporal constraints). The purpose of path planning, unlike motion planning which must be taken into consideration of dynamics, is to find a kinematically optimal path with the least time as well as model the environment completely. We discuss the fundamentals of these most successful robot 3D path...

  12. Success of Path Dependence Through Perpetuation of Failure During Reform

    OpenAIRE

    E Kasabov

    2010-01-01

    The primary purpose of this paper is to extend current debates about path dependence and to contribute to scholarship by addressing inadequately researched aspects of path dependence: the role of individuals in sustaining long-standing 'inefficient' institutions; the balance of 'path following' and 'path violation'; and path dependent resource utilisation, not resource allocation. These matters are illustrated through and discussed in the context of 'asset-stripping' and 'rent-seeking' in the...

  13. Developing an Advanced Life Support System for the Flexible Path into Deep Space

    Science.gov (United States)

    Jones, Harry W.; Kliss, Mark H.

    2010-01-01

    Long duration human missions beyond low Earth orbit, such as a permanent lunar base, an asteroid rendezvous, or exploring Mars, will use recycling life support systems to preclude supplying large amounts of metabolic consumables. The International Space Station (ISS) life support design provides a historic guiding basis for future systems, but both its system architecture and the subsystem technologies should be reconsidered. Different technologies for the functional subsystems have been investigated and some past alternates appear better for flexible path destinations beyond low Earth orbit. There is a need to develop more capable technologies that provide lower mass, increased closure, and higher reliability. A major objective of redesigning the life support system for the flexible path is achieving the maintainability and ultra-reliability necessary for deep space operations.

  14. FAW Technology Strategies of Low-Carbon Passenger Car

    Institute of Scientific and Technical Information of China (English)

    Li Jun

    2012-01-01

    Author analyzed the global background of low-carbon technology around the world,a technology & economy analysis model called TOS was developed in the paper,author analyzed technology paths for low-carbon Car in China based on the current technologies available and technologies to he developed in China,3 possible paths are presented based on the analysis,author also explained the FAW BlueWay technology strategies for low carbon cars both for short mid and long term objectives.Author concludes the paper with illustration of powertrain lineup for FAW BlueWay Technologies.

  15. FLIGHT PATH CONTROL FOR UNMANNED AERIAL VEHICLE

    Directory of Open Access Journals (Sweden)

    M. A. Al-Mashhadani

    2014-01-01

    Full Text Available Studying the optimized control law specified criteria on UAV while hovering over a path defined by the reference points in the inertial frame. An illustrative example is the  theoretical efficiency of the proposed provisions. 

  16. Stochastic Evolutionary Algorithms for Planning Robot Paths

    Science.gov (United States)

    Fink, Wolfgang; Aghazarian, Hrand; Huntsberger, Terrance; Terrile, Richard

    2006-01-01

    A computer program implements stochastic evolutionary algorithms for planning and optimizing collision-free paths for robots and their jointed limbs. Stochastic evolutionary algorithms can be made to produce acceptably close approximations to exact, optimal solutions for path-planning problems while often demanding much less computation than do exhaustive-search and deterministic inverse-kinematics algorithms that have been used previously for this purpose. Hence, the present software is better suited for application aboard robots having limited computing capabilities (see figure). The stochastic aspect lies in the use of simulated annealing to (1) prevent trapping of an optimization algorithm in local minima of an energy-like error measure by which the fitness of a trial solution is evaluated while (2) ensuring that the entire multidimensional configuration and parameter space of the path-planning problem is sampled efficiently with respect to both robot joint angles and computation time. Simulated annealing is an established technique for avoiding local minima in multidimensional optimization problems, but has not, until now, been applied to planning collision-free robot paths by use of low-power computers.

  17. Path Planning in a Dynamic Environment

    Directory of Open Access Journals (Sweden)

    Mohamed EL KHAILI

    2014-08-01

    Full Text Available Path planning is an important area in the control of autonomous mobile robots. Recent work has focused on aspects reductions in processing time than the memory requirements. A dynamic environment uses a lot of memory and hence the processing time increases too. Our approach is to reduce the processing time by the use of a pictorial approach to reduce the number of data used. In this paper, we present a path planning approach that operates in three steps. First, a construction of the visibility tree is performed. The following treatments are not performed on the original image but on the result tree whose elements are specific points of the environment linked by the relationship of visibility. We construct thereafter a visibility graph which one seeks the shortest path. This approach has a great interest because of its fast execution speed. The path search is extended also for the case where obstacles can move. The moving obstacles may be other mobile robots whose trajectories and speeds are known initially. At the end, some applications are provided on solving similar problem such civil aviation in order to guide plane avoiding collisions.

  18. Predictors of Retirement Satisfaction: A Path Model.

    Science.gov (United States)

    Kremer, Yael

    1985-01-01

    Examined adjustment to retirement among 310 former industrial and service workers. Respondents had come to terms with retirement and enjoyed their more relaxed lifestyle. Dominant variables in the path model were retirees' satisfaction with specific aspects of retirement: giving up work, activities with family and friends, rest, and free time. (BH)

  19. Learning paths and OER: trends and opportunities

    NARCIS (Netherlands)

    Janssen, José; Berlanga, Adriana; Koper, Rob

    2013-01-01

    Janssen, J., Berlanga, A. J., & Koper, R. (2013). Learning paths and OER: trends and opportunities. In R. Jacobi, H. Jelgerhuis, & N. van der Woert (Eds.), Trendreport Open Educational Resources 2013 (pp. 76-80). Utrecht: SURF Foundation - Special Interest Group Open Educational Resources SURF. Fina

  20. Demixing light paths inside disordered metamaterials

    NARCIS (Netherlands)

    Vellekoop, Ivo Micha; van Putten, E.G.; Putten, E.G.; Lagendijk, Aart; Mosk, Allard

    2008-01-01

    We experimentally demonstrate the first method to focus light inside disordered photonic metamaterials. In such materials, scattering prevents light from forming a geometric focus. Instead of geometric optics, we used multi-path interference to make the scattering process itself concentrate light on

  1. Bead-Fourier path integral molecular dynamics

    Science.gov (United States)

    Ivanov, Sergei D.; Lyubartsev, Alexander P.; Laaksonen, Aatto

    2003-06-01

    Molecular dynamics formulation of Bead-Fourier path integral method for simulation of quantum systems at finite temperatures is presented. Within this scheme, both the bead coordinates and Fourier coefficients, defining the path representing the quantum particle, are treated as generalized coordinates with corresponding generalized momenta and masses. Introduction of the Fourier harmonics together with the center-of-mass thermostating scheme is shown to remove the ergodicity problem, known to pose serious difficulties in standard path integral molecular dynamics simulations. The method is tested for quantum harmonic oscillator and hydrogen atom (Coulombic potential). The simulation results are compared with the exact analytical solutions available for both these systems. Convergence of the results with respect to the number of beads and Fourier harmonics is analyzed. It was shown that addition of a few Fourier harmonics already improves the simulation results substantially, even for a relatively small number of beads. The proposed Bead-Fourier path integral molecular dynamics is a reliable and efficient alternative to simulations of quantum systems.

  2. Unified classical path theories of pressure broadening.

    Science.gov (United States)

    Bottcher, C.

    1971-01-01

    Derivation of a unified classical path theory of pressure broadening, using only elementary concepts. It is shown that the theory of Smith, Cooper and Vidal (1969) is only correct at all frequencies to first order in the number density of perturbers.

  3. Path-breaking books in regional science

    NARCIS (Netherlands)

    Waldorf, BS

    2004-01-01

    This article presents a collection of regional science books that long-standing members of the Regional Science Association International (RSAI) identified as path-breaking books. The most frequently nominated books include the "classics" by Isard, the seminal books in urban economics by Alonso, Mut

  4. Transition paths in molecules at finite temperature

    Science.gov (United States)

    Pinski, F. J.; Stuart, A. M.

    2010-05-01

    In the zero temperature limit, it is well known that in systems evolving via Brownian dynamics, the most likely transition path between reactant and product may be found as a minimizer of the Freidlin-Wentzell action functional. An analog for finite temperature transitions is given by the Onsager-Machlup functional. The purpose of this work is to investigate properties of Onsager-Machlup minimizers. We study transition paths for thermally activated molecules governed by the Langevin equation in the overdamped limit of Brownian dynamics. Using gradient descent in pathspace, we minimize the Onsager-Machlup functional for a range of model problems in one and two dimensions and then for some simple atomic models including Lennard-Jones seven-atom and 38-atom clusters, as well as for a model of vacancy diffusion in a planar crystal. Our results demonstrate interesting effects, which can occur at nonzero temperature, showing transition paths that could not be predicted on the basis of the zero temperature limit. However the results also demonstrate unphysical features associated with such Onsager-Machlup minimizers. As there is a growing literature that addresses transition path sampling by related techniques, these insights add a potentially useful perspective into the interpretation of this body of work.

  5. Star-Paths, Stones and Horizon Astronomy

    Science.gov (United States)

    Brady, Bernadette

    2015-05-01

    Archaeoastronomers tend to approach ancient monuments focusing on the landscape and the horizon calendar events of sun and moon and, due to problems with precession, generally ignore the movement of the stars. However, locating the position of solar calendar points on the horizon can have other uses apart from calendar and/or cosmological purposes. This paper firstly suggests that the stars do not need to be ignored. By considering the evidence of the Phaenomena, a sky poem by Aratus of Soli, a third century BC Greek poet, and his use of second millennium BC star lore fragments, this paper argues that the stars were a part of the knowledge of horizon astronomy. Aratus' poem implied that the horizon astronomy of the late Neolithic and Bronze Age periods included knowledge of star-paths or 'linear constellations' that were defined by particular horizon calendar events and other azimuths. Knowledge of such star-paths would have enabled navigation and orientation, and by using permanent markers, constructed or natural, to define these paths, they were immune to precession as the stones could redefine a star-path for a future generation. Finally the paper presents other possible intentions behind the diverse orientation of passage tombs and some megalithic sites.

  6. Demixing light paths inside disordered metamaterials

    NARCIS (Netherlands)

    Vellekoop, I.M.; Putten, E.G.; Lagendijk, A.; Mosk, A.P.

    2008-01-01

    We experimentally demonstrate the first method to focus light inside disordered photonic metamaterials. In such materials, scattering prevents light from forming a geometric focus. Instead of geometric optics, we used multi-path interference to make the scattering process itself concentrate light on

  7. Damage detection using frequency shift path

    Science.gov (United States)

    Wang, Longqi; Lie, Seng Tjhen; Zhang, Yao

    2016-01-01

    This paper introduces a novel concept called FREquency Shift (FRESH) path to describe the dynamic behavior of structures with auxiliary mass. FRESH path combines the effects of frequency shifting and amplitude changing into one space curve, providing a tool for analyzing structure health status and properties. A damage index called FRESH curvature is then proposed to detect local stiffness reduction. FRESH curvature can be easily adapted for a particular problem since the sensitivity of the index can be adjusted by changing auxiliary mass or excitation power. An algorithm is proposed to adjust automatically the contribution from frequency and amplitude in the method. Because the extraction of FRESH path requires highly accurate frequency and amplitude estimators; therefore, a procedure based on discrete time Fourier transform is introduced to extract accurate frequency and amplitude with the time complexity of O (n log n), which is verified by simulation signals. Moreover, numerical examples with different damage sizes, severities and damping are presented to demonstrate the validity of the proposed damage index. In addition, applications of FRESH path on two steel beams with different damages are presented and the results show that the proposed method is valid and computational efficient.

  8. Quad-rotor flight path energy optimization

    Science.gov (United States)

    Kemper, Edward

    Quad-Rotor unmanned areal vehicles (UAVs) have been a popular area of research and development in the last decade, especially with the advent of affordable microcontrollers like the MSP 430 and the Raspberry Pi. Path-Energy Optimization is an area that is well developed for linear systems. In this thesis, this idea of path-energy optimization is extended to the nonlinear model of the Quad-rotor UAV. The classical optimization technique is adapted to the nonlinear model that is derived for the problem at hand, coming up with a set of partial differential equations and boundary value conditions to solve these equations. Then, different techniques to implement energy optimization algorithms are tested using simulations in Python. First, a purely nonlinear approach is used. This method is shown to be computationally intensive, with no practical solution available in a reasonable amount of time. Second, heuristic techniques to minimize the energy of the flight path are tested, using Ziegler-Nichols' proportional integral derivative (PID) controller tuning technique. Finally, a brute force look-up table based PID controller is used. Simulation results of the heuristic method show that both reliable control of the system and path-energy optimization are achieved in a reasonable amount of time.

  9. Path-breaking books in regional science

    NARCIS (Netherlands)

    Waldorf, BS

    2004-01-01

    This article presents a collection of regional science books that long-standing members of the Regional Science Association International (RSAI) identified as path-breaking books. The most frequently nominated books include the "classics" by Isard, the seminal books in urban economics by Alonso, Mut

  10. Path-breaking books in regional science

    NARCIS (Netherlands)

    Waldorf, BS

    This article presents a collection of regional science books that long-standing members of the Regional Science Association International (RSAI) identified as path-breaking books. The most frequently nominated books include the "classics" by Isard, the seminal books in urban economics by Alonso,

  11. A path following algorithm for mobile robots

    NARCIS (Netherlands)

    Bakker, T.; Asselt, van C.J.; Bontsema, J.; Müller, J.; Straten, van G.

    2010-01-01

    This paper considers path following control for a robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The platform is four-wheel steered and four-wheel driven. A diesel engine powers the wheels via a hydraulic transm

  12. Cutting Path Planning for Ruled Surface Impellers

    Institute of Scientific and Technical Information of China (English)

    Liang Quan; Wang Yongzhang; Fu Hongya; Han Zhenyu

    2008-01-01

    At present, most commercial computer-aided manufacturing (CAM) systems are deficient in efficiency and performances on generating tool path during machining impellers. To solve the problem, this article develops a special software to plan cutting path for ruled surface impellers. An approximation algorithm to generate cutting path for machining integral ruled surface impellers is proposed. By fitting sampling data points of an impeller blade into a curve, a model of ruled surface blade of an impeller is built up. Furthermore, by calculating the points where the cutter axis vector intersects the flee-form hub surface of an impeller, problems about, for instance, the ambiguity in calculation and machining the wide blade surface with a short flute cutter are solved. Finally, an integral impeller cutting path is planned by way of an integrated cutter location control algorithm. Simulation and machining tests with an impeller are performed on a 5-axis computer numerically controlled (CNC) mill machine, which shows the feasibility of the proposed algorithm.

  13. Contracting Graphs to Paths and Trees

    CERN Document Server

    Heggernes, Pinar; Lévêque, Benjamin; Lokshtanov, Daniel; Paul, Christophe

    2011-01-01

    Vertex deletion and edge deletion problems play a central role in Parameterized Complexity. Examples include classical problems like Feedback Vertex Set, Odd Cycle Transversal, and Chordal Deletion. Interestingly, the study of edge contraction problems of this type from a parameterized perspective has so far been left largely unexplored. We consider two basic edge contraction problems, which we call Path-Contractibility and Tree-Contractibility. Both problems take an undirected graph $G$ and an integer $k$ as input, and the task is to determine whether we can obtain a path or an acyclic graph, respectively, by contracting at most $k$ edges of $G$. Our main contribution is an algorithm with running time $4^{k+O(\\log^2 k)} + n^{O(1)}$ for Path-Contractibility and an algorithm with running time $4.88^k n^{O(1)}$ for Tree-Contractibility, based on a novel application of the color coding technique of Alon, Yuster and Zwick. Furthermore, we show that Path-Contractibility has a kernel with at most $5k+3$ vertices, w...

  14. Current Algebra in the Path Integral framework

    CERN Document Server

    Cardenas, V H; Saavedra, J

    1998-01-01

    In this letter we describe an approach to the current algebra based in the Path Integral formalism. We use this method for abelian and non-abelian quantum field theories in 1+1 and 2+1 dimensions and the correct expressions are obtained. Our results show the independence of the regularization of the current algebras.

  15. 14 CFR 25.111 - Takeoff path.

    Science.gov (United States)

    2010-01-01

    ... height equal to its wing span. (e) For airplanes equipped with standby power rocket engines, the takeoff... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff path. 25.111 Section 25.111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

  16. Global Cloud Liquid Water Path Simulations(.

    Science.gov (United States)

    Lemus, Lilia; Rikus, Lawrie; Martin, C.; Platt, R.

    1997-01-01

    A new parameterization of cloud liquid water and ice content has been included in the Bureau of Meteorology Global Assimilation and Prediction System. The cloud liquid water content is derived from the mean cloud temperatures in the model using an empirical relationship based on observations. The results from perpetual January and July simulations are presented and show that the total cloud water path steadily decreases toward high latitudes, with two relative maxima at midlatitudes and a peak at low latitudes. To validate the scheme, the simulated fields need to be processed to produce liquid water paths that can be directly compared with the corresponding field derived from Special Sensor Microwave/Imager (SSM/I) data. This requires the identification of cloud ice water content within the parameterization and a prescription to account for the treatment of strongly precipitating subgrid-scale cloud. The resultant cloud liquid water paths agree qualitatively with the SSM/I data but show some systematic errors that are attributed to corresponding errors in the model's simulation of cloud amounts. Given that a more quantitative validation requires substantial improvement in the model's diagnostic cloud scheme, the comparison with the SSM/I data indicates that the cloud water path, derived from the cloud liquid water content parameterization introduced in this paper, is consistent with the observations and can be usefully incorporated in the prediction system.

  17. Learning to improve path planning performance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pang C.

    1995-04-01

    In robotics, path planning refers to finding a short. collision-free path from an initial robot configuration to a desired configuratioin. It has to be fast to support real-time task-level robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To remedy this situation, we present and analyze a learning algorithm that uses past experience to increase future performance. The algorithm relies on an existing path planner to provide solutions to difficult tasks. From these solutions, an evolving sparse network of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a speedup-learning framework in which a slow but capable planner may be improved both cost-wise and capability-wise by a faster but less capable planner coupled with experience. The basic algorithm is suitable for stationary environments, and can be extended to accommodate changing environments with on-demand experience repair and object-attached experience abstraction. To analyze the algorithm, we characterize the situations in which the adaptive planner is useful, provide quantitative bounds to predict its behavior, and confirm our theoretical results with experiments in path planning of manipulators. Our algorithm and analysis are sufficiently, general that they may also be applied to other planning domains in which experience is useful.

  18. A path following algorithm for mobile robots

    NARCIS (Netherlands)

    Bakker, T.; Asselt, van C.J.; Bontsema, J.; Müller, J.; Straten, van G.

    2010-01-01

    This paper considers path following control for a robotic platform. The vehicle used for the experiments is a specially designed robotic platform for performing autonomous weed control. The platform is four-wheel steered and four-wheel driven. A diesel engine powers the wheels via a hydraulic

  19. Path integration in tactile perception of shapes.

    Science.gov (United States)

    Moscatelli, Alessandro; Naceri, Abdeldjallil; Ernst, Marc O

    2014-11-01

    Whenever we move the hand across a surface, tactile signals provide information about the relative velocity between the skin and the surface. If the system were able to integrate the tactile velocity information over time, cutaneous touch may provide an estimate of the relative displacement between the hand and the surface. Here, we asked whether humans are able to form a reliable representation of the motion path from tactile cues only, integrating motion information over time. In order to address this issue, we conducted three experiments using tactile motion and asked participants (1) to estimate the length of a simulated triangle, (2) to reproduce the shape of a simulated triangular path, and (3) to estimate the angle between two-line segments. Participants were able to accurately indicate the length of the path, whereas the perceived direction was affected by a direction bias (inward bias). The response pattern was thus qualitatively similar to the ones reported in classical path integration studies involving locomotion. However, we explain the directional biases as the result of a tactile motion aftereffect.

  20. Transaction costs and technological development: The case of the Danish fruit and vegetable industry

    DEFF Research Database (Denmark)

    Foss, Kirsten

    1996-01-01

    It is argued that technological change can be understood in terms of attempts to reduce transaction costs as well as production costs. Two types of paths of technological development are identified: a production cost minimizing path, and a transac cost minimizing path. The creation of new technol...... in addition to the conventional production perspective. The theoretical points are continiuously illustrated by the case of technological development in the Danish fruit and vegetable industry....

  1. On Realization of Technological productivity

    Institute of Scientific and Technical Information of China (English)

    SOILORW.

    2000-01-01

    Technology has been a major force in modem economic development and world economy, but technology is only potential productivity and has a long distance from real productive forces. There are two major paths in turning technology into real productive forces. First, technological innovation is a process in which technology is tranaformed into real productivity in essence . The market is another channel for transformation of technology into productive forces. The transformation of technology into productive forces has its laws and mechanisms. In China, there are many obstacles to transformation of technology into real productive forces. We must take seventeen pieces of countermeasures to overcome these obstacles, and speed up the realization of technological productive forces.

  2. Multiple stochastic paths scheme on partially-trusted relay quantum key distribution network

    Institute of Scientific and Technical Information of China (English)

    WEN Hao; HAN ZhengFui; ZHAO YiBo; GUO GuangCan; HONG PeiLin

    2009-01-01

    Quantum key distribution (QKD) technology provides proven unconditional point-to-point security based on fundamental quantum physics. A QKD network also holds promise for secure multi-user communications over long distances at high-speed transmission rates. Although many schemes have been proposed so far, the trusted relay QKD network is still the most practical and flexible scenario. In reality, the insecurity of certain relay sections cannot be ignored, so to solve the fatal security problems of partially-trusted relay networks we suggest a multiple stochastic paths scheme. Its features are- (i) a safe probability model that may be more practical for real applications; (ii) a multi-path scheme with an upper bound for the overall safe probability; (iii) an adaptive stochastic routing algorithm to generate sufficient different paths and hidden routes. Simulation results for a typical partially-trusted relay QKD network show that this generalized scheme is effective.

  3. Elongating axial conduction path design to enhance performance of cryogeinc compact pche (printed circuit heat exchanger)

    Science.gov (United States)

    Baek, Seungwhan; Kim, Jinhyuck; Hwang, Gyuwan; Jeong, Sangkwon

    2012-06-01

    PCHE (Printed Circuit Heat Exchanger) is one of the promising cryogenic compact heat exchangers due to its compactness, high NTU and robustness. The essential procedure for fabricating PCHE is chemical etching and diffusion bonding. These technologies can create sufficiently large heat transfer area for a heat exchanger with numerous micro channels (Dhheat exchanger when it is operated with a large temperature difference. Elongating the heat conduction path is implemented to reduce axial conduction in PCHE in this study. Two PCHEs with identical channel configuration are fabricated, for comparison, one of which is modified to have longer heat conduction path. Both heat exchangers are tested in cryogenic environment (300~70 K), and the modified PCHE shows better performance with significantly reduced axial conduction. The experimental results indicate that the modification of the heat conduction path is effective to increase the performance of PCHE. This paper discusses and analyses the thermal characteristics of the modified PCHE obtained experimentally.

  4. Construction of Time-Stamped Mobility Map for Path Tracking via Smith-Waterman Measurement Matching

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available Path tracking in wireless and mobile environments is a fundamental technology for ubiquitous location-based services (LBSs. In particular, it is very challenging to develop highly accurate and cost-efficient tracking systems applied to the anonymous areas where the floor plans are not available for security and privacy reasons. This paper proposes a novel path tracking approach for large Wi-Fi areas based on the time-stamped unlabeled mobility map which is constructed from Smith-Waterman received signal strength (RSS measurement matching. Instead of conventional location fingerprinting, we construct mobility map with the technique of dimension reduction from the raw measurement space into a low-dimensional embedded manifold. The feasibility of our proposed approach is verified by the real-world experiments in the HKUST campus Wi-Fi networks, sMobileNet. The experimental results prove that our approach is adaptive and capable of achieving an adequate precision level in path tracking.

  5. Global path planning of mobile robots using a memetic algorithm

    Science.gov (United States)

    Zhu, Zexuan; Wang, Fangxiao; He, Shan; Sun, Yiwen

    2015-08-01

    In this paper, a memetic algorithm for global path planning (MAGPP) of mobile robots is proposed. MAGPP is a synergy of genetic algorithm (GA) based global path planning and a local path refinement. Particularly, candidate path solutions are represented as GA individuals and evolved with evolutionary operators. In each GA generation, the local path refinement is applied to the GA individuals to rectify and improve the paths encoded. MAGPP is characterised by a flexible path encoding scheme, which is introduced to encode the obstacles bypassed by a path. Both path length and smoothness are considered as fitness evaluation criteria. MAGPP is tested on simulated maps and compared with other counterpart algorithms. The experimental results demonstrate the efficiency of MAGPP and it is shown to obtain better solutions than the other compared algorithms.

  6. Path dependence in energy systems and economic development

    Science.gov (United States)

    Fouquet, Roger

    2016-08-01

    Energy systems are subject to strong and long-lived path dependence, owing to technological, infrastructural, institutional and behavioural lock-ins. Yet, with the prospect of providing accessible cheap energy to stimulate economic development and reduce poverty, governments often invest in large engineering projects and subsidy policies. Here, I argue that while these may achieve their objectives, they risk locking their economies onto energy-intensive pathways. Thus, particularly when economies are industrializing, and their energy systems are being transformed and are not yet fully locked-in, policymakers should take care before directing their economies onto energy-intensive pathways that are likely to be detrimental to their long-run prosperity.

  7. Low carbon transition and sustainable development path of tourism industry

    Science.gov (United States)

    Zhu, Hongbing; Zhang, Jing; Zhao, Lei; Jin, Shenglang

    2017-05-01

    The low carbon transition is as much a transformative technology shift as it represents a response to global environment challenges. The low carbon paradigm presents a new direction of change for tourism industry. However, the lack of theoretical frameworks on low carbon transformation in tourism industry context provides a significant knowledge gap. This paper firstly investigates the relationships between low carbon and sustainable development, followed by exploring the existing challenges of tourism sustainable development. At last, this paper presents a sustainable development path framework for low carbon transition of tourism industry, which include accelerating deployment of renewable energy, energy-saving green building construction, improving green growth investment, and adopting a sustainable consumption and production system, in order to promote energy and water efficiency, waste management, GHG emissions mitigation and eventually enhance its sustainability.

  8. Interference factors regarding the path of insertion of rotational-path removable partial dentures

    National Research Council Canada - National Science Library

    Chan-Te Huang; Fang-Chun Liu; Kwing-Chi Luk

    2017-01-01

    Background: The aims of this study were to evaluate the effect of the location of the rotational center and the morphology of teeth resulting in interference with the rotational path of insertion and to estimate...

  9. Three-Dimensional Path Planning and Guidance of Leg Vascular Based on Improved Ant Colony Algorithm in Augmented Reality.

    Science.gov (United States)

    Gao, Ming-ke; Chen, Yi-min; Liu, Quan; Huang, Chen; Li, Ze-yu; Zhang, Dian-hua

    2015-11-01

    Preoperative path planning plays a critical role in vascular access surgery. Vascular access surgery has superior difficulties and requires long training periods as well as precise operation. Yet doctors are on different leves, thus bulky size of blood vessels is usually chosen to undergo surgery and other possible optimal path is not considered. Moreover, patients and surgeons will suffer from X-ray radiation during the surgical procedure. The study proposed an improved ant colony algorithm to plan a vascular optimal three-dimensional path with overall consideration of factors such as catheter diameter, vascular length, diameter as well as the curvature and torsion. To protect the doctor and patient from exposing to X-ray long-term, the paper adopted augmented reality technology to register the reconstructed vascular model and physical model meanwhile, locate catheter by the electromagnetic tracking system and used Head Mounted Display to show the planning path in real time and monitor catheter push procedure. The experiment manifests reasonableness of preoperative path planning and proves the reliability of the algorithm. The augmented reality experiment real time and accurately displays the vascular phantom model, planning path and the catheter trajectory and proves the feasibility of this method. The paper presented a useful and feasible surgical scheme which was based on the improved ant colony algorithm to plan vascular three-dimensional path in augmented reality. The study possessed practical guiding significance in preoperative path planning, intraoperative catheter guiding and surgical training, which provided a theoretical method of path planning for vascular access surgery. It was a safe and reliable path planning approach and possessed practical reference value.

  10. A Path Space Extension for Robust Light Transport Simulation

    DEFF Research Database (Denmark)

    Hachisuka, Toshiya; Pantaleoni, Jacopo; Jensen, Henrik Wann

    2012-01-01

    We present a new sampling space for light transport paths that makes it possible to describe Monte Carlo path integration and photon density estimation in the same framework. A key contribution of our paper is the introduction of vertex perturbations, which extends the space of paths with loosely...... coupled connections. The new framework enables the computation of path probabilities in the same space under the same measure, which allows us to use multiple importance sampling to combine Monte Carlo path integration and photon density estimation. The resulting algorithm, unified path sampling, can...

  11. Strained tetragonal states and Bain paths in metals

    CERN Document Server

    Alippi, P; Scheffler, M

    1996-01-01

    Paths of tetragonal states between two phases of a material, such as bcc and fcc, are called Bain paths. Two simple Bain paths can be defined in terms of special imposed stresses, one of which applies directly to strained epitaxial films. Each path goes far into the range of nonlinear elasticity and reaches a range of structural parameters in which the structure is inherently unstable. In this paper we identify and analyze the general properties of these paths by density functional theory. Special examples include vanadium, cobalt and copper, and the epitaxial path is used to identify an epitaxial film as related uniquely to a bulk phase.

  12. The Importance of the Electron Mean Free Path for Superconducting RF Cavities

    CERN Document Server

    Maniscalco, J T; Liepe, M

    2016-01-01

    Impurity-doping is an exciting new technology in the field of SRF, producing cavities with record-high quality factor $Q_0$ and BCS surface resistance that decreases with increasing RF field. Recent theoretical work has offered a promising explanation for this anti-Q-slope, but the link between the decreasing surface resistance and the short mean free path of doped cavities has remained elusive. In this work we investigate this link, finding that the magnitude of this decrease varies directly with the mean free path: shorter mean free paths correspond with stronger anti-Q-slopes. We draw a theoretical connection between the mean free path and the overheating of the quasiparticles, which leads to the reduction of the anti-Q-slope towards the normal Q-slope of long-mean-free-path cavities. We also investigate the sensitivity of the residual resistance to trapped magnetic flux, a property which is greatly enhanced for doped cavities, and calculate an optimal doping regime for a given amount of trapped flux. We f...

  13. Study on the stress path dependency of collapse behavior of Gorgan loess implementing unsaturated oedometer devices

    Directory of Open Access Journals (Sweden)

    Haeri S. Mohsen

    2016-01-01

    Full Text Available Collapsible soils such as loess are particular types of problematic soils, whose collapse potential have caused severe damages to the buildings and structures. Loess is susceptible to large and sudden volume reduction upon wetting in constant normal stress or upon increasing normal stress in constant water content or a combination of these two stress paths. In this research both of these collapse induced paths: wetting and stress paths are investigated on undisturbed specimens of a Loess to observe the effect of various parameters on the collapse behavior of the tested soil., Seven controlled matric suction unsaturated oedometer tests have been conducted on undisturbed specimens taken from loessial soil of Gorgan, a city in Golestan province in Iran to study the collapse mechanisms of this type of soils. Two identical sets of unsaturated oedometer apparatuses designed and developed at Sharif University of Technology, with the capability of controlling matric suction have been utilized. In these tests, the matric suction, vertical net stress, volumetric water content, and vertical deformation of the samples have been controlled and recorded. Tests have been performed under two separate stress paths: constant matric suction with varying vertical net stress (loading and unloading and constant vertical net stress with varying matric suction (wetting and drying. Obtained results show the high collapse potential of the tested soil and significant effects of stress path, matric suction, and vertical net stress on the collapse behavior of the tested soil.

  14. A whole-path importance-sampling scheme for Feynman path integral calculations of absolute partition functions and free energies.

    Science.gov (United States)

    Mielke, Steven L; Truhlar, Donald G

    2016-01-21

    Using Feynman path integrals, a molecular partition function can be written as a double integral with the inner integral involving all closed paths centered at a given molecular configuration, and the outer integral involving all possible molecular configurations. In previous work employing Monte Carlo methods to evaluate such partition functions, we presented schemes for importance sampling and stratification in the molecular configurations that constitute the path centroids, but we relied on free-particle paths for sampling the path integrals. At low temperatures, the path sampling is expensive because the paths can travel far from the centroid configuration. We now present a scheme for importance sampling of whole Feynman paths based on harmonic information from an instantaneous normal mode calculation at the centroid configuration, which we refer to as harmonically guided whole-path importance sampling (WPIS). We obtain paths conforming to our chosen importance function by rejection sampling from a distribution of free-particle paths. Sample calculations on CH4 demonstrate that at a temperature of 200 K, about 99.9% of the free-particle paths can be rejected without integration, and at 300 K, about 98% can be rejected. We also show that it is typically possible to reduce the overhead associated with the WPIS scheme by sampling the paths using a significantly lower-order path discretization than that which is needed to converge the partition function.

  15. Transition path time distribution and the transition path free energy barrier.

    Science.gov (United States)

    Pollak, Eli

    2016-10-19

    The recent experimental measurement of the transition path time distributions of proteins presents several challenges to theory. Firstly, why do the fits of the experimental data to a theoretical expression lead to barrier heights which are much lower than the free energies of activation of the observed transitions? Secondly, there is the theoretical question of determining the transition path time distribution, without invoking the Smoluchowski limit. In this paper, we derive an exact expression for a transition path time distribution which is valid for arbitrary memory friction using the normal mode transformation which underlies Kramers' rate theory. We then recall that for low barriers, there is a noticeable difference between the transition path time distribution obtained with absorbing boundary conditions and free boundary conditions. For the former, the transition times are shorter, since recrossings of the boundaries are disallowed. As a result, if one uses the distribution based on absorbing boundary conditions to fit the experimental data, one will find that the transition path barrier will be larger than the values found based on a theory with free boundary conditions. We then introduce the paradigm of a transition path barrier height, and show that one should always expect it to be much smaller than the activation energy.

  16. Global path planning approach based on ant colony optimization algorithm

    Institute of Scientific and Technical Information of China (English)

    WEN Zhi-qiang; CAI Zi-xing

    2006-01-01

    Ant colony optimization (ACO) algorithm was modified to optimize the global path. In order to simulate the real ant colonies, according to the foraging behavior of ant colonies and the characteristic of food, conceptions of neighboring area and smell area were presented. The former can ensure the diversity of paths and the latter ensures that each ant can reach the goal. Then the whole path was divided into three parts and ACO was used to search the second part path. When the three parts pathes were adjusted,the final path was found. The valid path and invalid path were defined to ensure the path valid. Finally, the strategies of the pheromone search were applied to search the optimum path. However, when only the pheromone was used to search the optimum path, ACO converges easily. In order to avoid this premature convergence, combining pheromone search and random search, a hybrid ant colony algorithm(HACO) was used to find the optimum path. The comparison between ACO and HACO shows that HACO can be used to find the shortest path.

  17. 高速公路路径识别设计及应用%Highway Design and Application Path Identification

    Institute of Scientific and Technical Information of China (English)

    卢桢

    2014-01-01

    The motorway ring network path ambiguity problem, effective measures to solve the ring network path ambiguity problem. Construction of the province to identify the network path through four level to achieve functional license plate recognition path information collection and many other core businesses. Describes the architecture path identification technology, and pointed out the direction of future development of identification technology path to the operator to bring greater economic benefits.%分析了高速公路环网中路径二义性问题,提出了有效解决环网中路径二义性问题的措施。通过四个层级构建全省路径识别网,以实现车牌识别路径信息采集等多项核心业务的功能。阐述了路径识别技术的构架,指出未来发展路径识别技术的方向,给运营方带来较大的经济效益。

  18. Vehicle path tracking by integrated chassis control

    Institute of Scientific and Technical Information of China (English)

    Saman Salehpour; Yaghoub Pourasad; Seyyed Hadi Taheri

    2015-01-01

    The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator (LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization (PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10%and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance.

  19. Broadband Phase Spectroscopy over Turbulent Air Paths.

    Science.gov (United States)

    Giorgetta, Fabrizio R; Rieker, Gregory B; Baumann, Esther; Swann, William C; Sinclair, Laura C; Kofler, Jon; Coddington, Ian; Newbury, Nathan R

    2015-09-01

    Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mode path combined with the intrinsic frequency stability and high sampling speed associated with dual-comb spectroscopy. The atmospheric phase spectrum is measured across 2 km of air at each of the 70,000 comb teeth spanning 233  cm(-1) across hundreds of near-infrared rovibrational resonances of CO(2), CH(4), and H(2)O with submilliradian uncertainty, corresponding to a 10(-13) refractive index sensitivity. Trace gas concentrations extracted directly from the phase spectrum reach 0.7 ppm uncertainty, demonstrated here for CO(2). While conventional broadband spectroscopy only measures intensity absorption, this approach enables measurement of the full complex susceptibility even in practical open path sensing.

  20. Quantum tunneling from paths in complex time

    CERN Document Server

    Bramberger, Sebastian F; Lehners, Jean-Luc

    2016-01-01

    We study quantum mechanical tunneling using complex solutions of the classical field equations. Simple visualization techniques allow us to unify and generalize previous treatments, and straightforwardly show the connection to the standard approach using Euclidean instanton solutions. We demonstrate that the negative modes of solutions along various contours in the complex time plane reveal which paths contribute to tunneling and which do not, and we provide a criterion for identifying the negative modes. Central to our approach is the solution of the background and perturbation equations not only along a single path, but over an extended region of the complex time plane. Our approach allows for a fully continuous and coherent treatment of classical evolution interspersed by quantum tunneling events, and is applicable in situations where singularities are present and also where Euclidean solutions might not exist.

  1. Hamiltonian formalism and path entropy maximization

    Science.gov (United States)

    Davis, Sergio; González, Diego

    2015-10-01

    Maximization of the path information entropy is a clear prescription for constructing models in non-equilibrium statistical mechanics. Here it is shown that, following this prescription under the assumption of arbitrary instantaneous constraints on position and velocity, a Lagrangian emerges which determines the most probable trajectory. Deviations from the probability maximum can be consistently described as slices in time by a Hamiltonian, according to a nonlinear Langevin equation and its associated Fokker-Planck equation. The connections unveiled between the maximization of path entropy and the Langevin/Fokker-Planck equations imply that missing information about the phase space coordinate never decreases in time, a purely information-theoretical version of the second law of thermodynamics. All of these results are independent of any physical assumptions, and thus valid for any generalized coordinate as a function of time, or any other parameter. This reinforces the view that the second law is a fundamental property of plausible inference.

  2. UAV Path Planning using MILP with Experiments

    Directory of Open Access Journals (Sweden)

    Anders Albert

    2017-01-01

    Full Text Available In this paper, we look at the problem of tracking icebergs using multiple Unmanned Aerial Vehicles (UAVs. Our solutions use combinatorial optimization for UAV path planning by formulating a mixed integer linear programing (MILP optimization problem. To demonstrate the approach, we present both a simulation and a practical experiment. The simulation demonstrates the possibilities of the MILP algorithm by constructing a case where three UAVs help a boat make a safe passage through an area with icebergs. Furthermore, we compare the performance of three against a single UAV. In the practical experiment, we take the first step towards full-scale experiments. We run the algorithm on a ground station and use it to set the path for a UAV tracking five simulated icebergs.

  3. Path Integral Bosonization of Massive GNO Fermions

    CERN Document Server

    Park, Q H

    1997-01-01

    We show the quantum equivalence between certain symmetric space sine-Gordon models and the massive free fermions. In the massless limit, these fermions reduce to the free fermions introduced by Goddard, Nahm and Olive (GNO) in association with symmetric spaces $K/G$. A path integral formulation is given in terms of the Wess-Zumino-Witten action where the field variable $g$ takes value in the orthogonal, unitary, and symplectic representations of the group $G$ in the basis of the symmetric space. We show that, for example, such a path integral bosonization is possible when the symmetric spaces $K/G$ are $SU(N) the relation between massive GNO fermions and the nonabelian solitons, and explain the restriction imposed on the fermion mass matrix due to the integrability of the bosonic model.

  4. Exploiting Deterministic TPG for Path Delay Testing

    Institute of Scientific and Technical Information of China (English)

    李晓维

    2000-01-01

    Detection of path delay faults requires two-pattern tests. BIST technique provides a low-cost test solution. This paper proposes an approach to designing a cost-effective deterministic test pattern generator (TPG) for path delay testing. Given a set of pre-generated test-pairs with pre-determined fault coverage, a deterministic TPG is synthesized to apply the given test-pair set in a limited test time. To achieve this objective, configurable linear feedback shift register (LFSR) structures are used. Techniques are developed to synthesize such a TPG, which is used to generate an unordered deterministic test-pair set. The resulting TPG is very efficient in terms of hardware size and speed performance. Simulation of academic benchmark circuits has given good results when compared to alternative solutions.

  5. Strong path convergence from Loewner driving convergence

    CERN Document Server

    Sheffield, Scott

    2010-01-01

    We show that, under mild assumptions on the limiting curve, a sequence of simple chordal planar curves converges uniformly whenever certain Loewner driving functions converge. We extend this result to random curves. The random version applies in particular to random lattice paths that have chordal SLE as a scaling limit, with kappa less than 8 (non-space-filling). Existing SLE convergence proofs often begin by showing that the Loewner driving functions of these paths (viewed from infinity) converge to Brownian motion. Unfortunately, this is not sufficient, and additional arguments are required to complete the proofs. We show that driving function convergence is sufficient if it can be established for both parametrization directions and a generic target.

  6. Families of graph-different Hamilton paths

    CERN Document Server

    Körner, János; Simonyi, Gábor

    2011-01-01

    Let D be an arbitrary subset of the natural numbers. For every n, let M(n;D) be the maximum of the cardinality of a set of Hamiltonian paths in the complete graph K_n such that the union of any two paths from the family contains a not necessarily induced cycle of some length from D. We determine or bound the asymptotics of M(n;D) in various special cases. This problem is closely related to that of the permutation capacity of graphs and constitutes a further extension of the problem area around Shannon capacity. We also discuss how to generalize our cycle-difference problems and present an example where cycles are replaced by 4-cliques. These problems are in a natural duality to those of graph intersection, initiated by Erd\\"os, Simonovits and S\\'os. The lack of kernel structure as a natural candidate for optimum makes our problems quite challenging.

  7. Microstructural path analysis of martensite burst

    Directory of Open Access Journals (Sweden)

    Paulo Rangel Rios

    2010-03-01

    Full Text Available Modeling the martensite reaction requires reckoning with spatial aspects of the reaction. For that, we used formal kinetics, more specifically, the microstructural path method (MPM to analyze the microstructure observed in a burst. The microstructural path analysis revealed that the size of the spread cluster in extended space, characterized by the Vandermeer and Juul-Jensen's impingement compensated mean intercept length, λG, remained constant, independently of the parent austenite grain size. Moreover, current analysis introduced a purely formal description of the reaction progress by taking the parent austenite grain size as the progress variable. This description worked very well and resulted in a relationship between the volume fraction of partially transformed austenite, V VG, and austenite grain size, λG. The significance of these findings in the light of the advantages and disadvantages of formal kinetics is discussed.

  8. Quantum gravitation the Feynman path integral approach

    CERN Document Server

    Hamber, Herbert W

    2009-01-01

    The book covers the theory of Quantum Gravitation from the point of view of Feynman path integrals. These provide a manifestly covariant approach in which fundamental quantum aspects of the theory such as radiative corrections and the renormalization group can be systematically and consistently addressed. The path integral method is suitable for both perturbative as well as non-perturbative studies, and is known to already provide a framework of choice for the theoretical investigation of non-abelian gauge theories, the basis for three of the four known fundamental forces in nature. The book thus provides a coherent outline of the present status of the theory gravity based on Feynman’s formulation, with an emphasis on quantitative results. Topics are organized in such a way that the correspondence to similar methods and results in modern gauge theories becomes apparent. Covariant perturbation theory are developed using the full machinery of Feynman rules, gauge fixing, background methods and ghosts. The ren...

  9. Quantum Measurement and Extended Feynman Path Integral

    Institute of Scientific and Technical Information of China (English)

    文伟; 白彦魁

    2012-01-01

    Quantum measurement problem has existed many years and inspired a large of literature in both physics and philosophy, but there is still no conclusion and consensus on it. We show it can be subsumed into the quantum theory if we extend the Feynman path integral by considering the relativistic effect of Feynman paths. According to this extended theory, we deduce not only the Klein-Gordon equation, but also the wave-function-collapse equation. It is shown that the stochastic and instantaneous collapse of the quantum measurement is due to the "potential noise" of the apparatus or environment and "inner correlation" of wave function respectively. Therefore, the definite-status of the macroscopic matter is due to itself and this does not disobey the quantum mechanics. This work will give a new recognition for the measurement problem.

  10. An alternative path integral for quantum gravity

    Science.gov (United States)

    Krishnan, Chethan; Kumar, K. V. Pavan; Raju, Avinash

    2016-10-01

    We define a (semi-classical) path integral for gravity with Neumann boundary conditions in D dimensions, and show how to relate this new partition function to the usual picture of Euclidean quantum gravity. We also write down the action in ADM Hamiltonian formulation and use it to reproduce the entropy of black holes and cosmological horizons. A comparison between the (background-subtracted) covariant and Hamiltonian ways of semi-classically evaluating this path integral in flat space reproduces the generalized Smarr formula and the first law. This "Neumann ensemble" perspective on gravitational thermodynamics is parallel to the canonical (Dirichlet) ensemble of Gibbons-Hawking and the microcanonical approach of Brown-York.

  11. An Alternate Path Integral for Quantum Gravity

    CERN Document Server

    Krishnan, Chethan; Raju, Avinash

    2016-01-01

    We define a (semi-classical) path integral for gravity with Neumann boundary conditions in $D$ dimensions, and show how to relate this new partition function to the usual picture of Euclidean quantum gravity. We also write down the action in ADM Hamiltonian formulation and use it to reproduce the entropy of black holes and cosmological horizons. A comparison between the (background-subtracted) covariant and Hamiltonian ways of semi-classically evaluating this path integral in flat space reproduces the generalized Smarr formula and the first law. This "Neumann ensemble" perspective on gravitational thermodynamics is parallel to the canonical (Dirichlet) ensemble of Gibbons-Hawking and the microcanonical approach of Brown-York.

  12. An alternative path integral for quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Chethan; Kumar, K.V. Pavan; Raju, Avinash [Center for High Energy Physics, Indian Institute of Science,Bangalore 560012 (India)

    2016-10-10

    We define a (semi-classical) path integral for gravity with Neumann boundary conditions in D dimensions, and show how to relate this new partition function to the usual picture of Euclidean quantum gravity. We also write down the action in ADM Hamiltonian formulation and use it to reproduce the entropy of black holes and cosmological horizons. A comparison between the (background-subtracted) covariant and Hamiltonian ways of semi-classically evaluating this path integral in flat space reproduces the generalized Smarr formula and the first law. This “Neumann ensemble” perspective on gravitational thermodynamics is parallel to the canonical (Dirichlet) ensemble of Gibbons-Hawking and the microcanonical approach of Brown-York.

  13. Dominating Sets and Domination Polynomials of Paths

    Directory of Open Access Journals (Sweden)

    Saeid Alikhani

    2009-01-01

    Full Text Available Let G=(V,E be a simple graph. A set S⊆V is a dominating set of G, if every vertex in V\\S is adjacent to at least one vertex in S. Let 𝒫ni be the family of all dominating sets of a path Pn with cardinality i, and let d(Pn,j=|𝒫nj|. In this paper, we construct 𝒫ni, and obtain a recursive formula for d(Pn,i. Using this recursive formula, we consider the polynomial D(Pn,x=∑i=⌈n/3⌉nd(Pn,ixi, which we call domination polynomial of paths and obtain some properties of this polynomial.

  14. Constructing Sublinear Expectations on Path Space

    CERN Document Server

    Nutz, Marcel

    2012-01-01

    We provide a general construction of time-consistent sublinear expectations on the space of continuous paths. It yields the existence of the conditional G-expectation of a Borel-measurable (rather than quasi-continuous) random variable, a generalization of the random G-expectation, and an optional sampling theorem that holds without exceptional set. Our results also shed light on the inherent limitations to constructing sublinear expectations through aggregation.

  15. Extreme paths in oriented 2D Percolation

    OpenAIRE

    Andjel, E. D.; Gray, L. F.

    2014-01-01

    A useful result about leftmost and rightmost paths in two dimensional bond percolation is proved. This result was introduced without proof in \\cite{G} in the context of the contact process in continuous time. As discussed here, it also holds for several related models, including the discrete time contact process and two dimensional site percolation. Among the consequences are a natural monotonicity in the probability of percolation between different sites and a somewhat counter-intuitive corr...

  16. Path integral measure for gravitational interactions

    Directory of Open Access Journals (Sweden)

    Kazuo Fujikawa

    1983-10-01

    Full Text Available It is pointed out that the path-integral variables as well as the local measure for gravitational interactions are uniquely specified if one imposes the anomaly-free condition on the Becchi-Rouet-Stora supersymmetry associated with general coordinate transformations. This prescription is briefly illustrated for the Einstein gravity and supergravity in four space-time dimensions and the relativistic string theory in two dimensions.

  17. Critical crack path assessments in failure investigations

    Directory of Open Access Journals (Sweden)

    Robert D. Caligiuri

    2015-10-01

    Full Text Available This paper presents a case study in which identification of the controlling crack path was critical to identifying the root cause of the failure. The case involves the rupture of a 30-inch (0.76 m natural gas pipeline in 2010 that tragically led to the destruction of a number of homes and the loss of life. The segment of the pipeline that ruptured was installed in 1956. The longitudinal seam of the segment that ruptured was supposed to have been fabricated by double submerged arc welding. Unfortunately, portions of the segment only received a single submerged arc weld on the outside, leaving unwelded areas on the inside diameter. Post-failure examination of the segment revealed that the rupture originated at one of these unwelded areas. Examination also revealed three additional crack paths or zones emanating from the unwelded area: a zone of ductile tearing, a zone of fatigue, and a zone of cleavage fracture, in that sequence. Initial investigators ignored the ductile tear, assumed the critical crack path was the fatigue component, and (incorrectly concluded that the root cause of the incident was the failure of the operator to hydrotest the segment after it was installed in 1956. However, as discussed in this paper, the critical path or mechanism was the ductile tear. Furthermore, it was determined that the ductile tear was created during the hydrotest at installation by a mechanism known as pressure reversal. Thus the correct root cause of the rupture was the hydrotest the operator subjected the segment to at installation, helping to increase the awareness of operators and regulators about the potential problems associated with hydrotesting.

  18. A Path Integral Approach To Noncommutative Superspace

    CERN Document Server

    Chepelev, I; Chepelev, Iouri; Ciocarlie, Calin

    2003-01-01

    A path integral formula for the associative star-product of two superfields is proposed. It is a generalization of the Kontsevich-Cattaneo-Felder's formula for the star-product of functions of bosonic coordinates. The associativity of the star-product imposes certain conditions on the background of our sigma model. For generic background the action is not supersymmetric. The supersymmetry invariance of the action constrains the background and leads to a simple formula for the star-product.

  19. Pedestrian traffic: on the quickest path

    Science.gov (United States)

    Kretz, Tobias

    2009-03-01

    When a large group of pedestrians moves around a corner, most pedestrians do not follow the shortest path, which is to stay as close as possible to the inner wall, but try to minimize the travel time. For this they accept to move on a longer path with some distance to the corner, to avoid large densities and by this succeed in maintaining a comparatively high speed. In many models of pedestrian dynamics the basic rule of motion is often either 'move as far as possible toward the destination' or—reformulated—'of all coordinates accessible in this time step move to the one with the smallest distance to the destination'. On top of this rule modifications are placed to make the motion more realistic. These modifications usually focus on local behavior and neglect long-ranged effects. Compared to real pedestrians this leads to agents in a simulation valuing the shortest path a lot better than the quickest. So, in a situation such as the movement of a large crowd around a corner, one needs an additional element in a model of pedestrian dynamics that makes the agents deviate from the rule of the shortest path. In this work it is shown how this can be achieved by using a flood fill dynamic potential field method, where during the filling process the value of a field cell is not increased by 1, but by a larger value, if it is occupied by an agent. This idea may be an obvious one: however, the tricky part—and therefore in a strict sense the contribution of this work—is (a) to minimize unrealistic artifacts, as naive flood fill metrics deviate considerably from the Euclidean metric and in this respect yield large errors, (b) do this with limited computational effort and (c) keep agents' movement at very low densities unaltered.

  20. Bloch oscillations of path-entangled photons.

    Science.gov (United States)

    Bromberg, Yaron; Lahini, Yoav; Silberberg, Yaron

    2010-12-31

    We show that when photons in N-particle path-entangled |N,0)+|0,N) or N00N states undergo Bloch oscillations, they exhibit a periodic transition between spatially bunched and antibunched states. The period of the bunching-antibunching oscillation is N times faster than the period of the oscillation of the photon density, manifesting the unique coherence properties of N00N states. The transition occurs even when the photons are well separated in space.

  1. Flux Control in Networks of Diffusion Paths

    Energy Technology Data Exchange (ETDEWEB)

    A. I. Zhmoginov and N. J. Fisch

    2009-07-08

    A class of optimization problems in networks of intersecting diffusion domains of a special form of thin paths has been considered. The system of equations describing stationary solutions is equivalent to an electrical circuit built of intersecting conductors. The solution of an optimization problem has been obtained and extended to the analogous electrical circuit. The interest in this network arises from, among other applications, an application to wave-particle diffusion through resonant interactions in plasma.

  2. Civil Society and Paths to Abolition

    Directory of Open Access Journals (Sweden)

    Seymour DRESCHER

    2015-12-01

    Full Text Available Abstract Through a comparative analysis, this article aims to present an overview of British, French, Russian, American and Brazilian abolitionist action, between the late eighteenth century and throughout the nineteenth century. Indicating the struggles of pro-abolition civil associations, the paths taken in Britain, France, the US and Brazil are presented in parallel - either to emphasize approaches, either to highlight the undeniable peculiarities - revealing the marks of violence and negotiation present in the emancipation process.

  3. Dynamic Shortest Path Algorithms for Hypergraphs

    Science.gov (United States)

    2012-01-01

    Performance comparison of algorithms for the dynamic shortest path problem,” IEICE Transactions on Fundamentals of Electronics , Communications and...computation,” IEEE/ACM Transactions on Networking, vol. 8, no. 6, pp. 734–746, 2000. [8] G. Ramalingam and T. Reps, “An incremental algorithm for a...multihop performance,” IEEE Transactions on Mobile Computing, pp. 337–348, 2003. [17] S. Chachulski, M. Jennings, S. Katti, and D. Katabli, “Trading

  4. Learner Autonomy and New Technologies.

    Science.gov (United States)

    Raya, Manuel Jimenez; Fernandez, Jose Maria Perez

    2002-01-01

    Presents paths for theoretical research and practical procedures that may help teachers make new technology pedagogically relevant. Discusses the need to develop learner autonomy to help students process information in meaningful ways and become independent learners by developing effective learning strategies, transfer skills, and a greater sense…

  5. Path description of coordinate-space amplitudes

    Science.gov (United States)

    Erdoǧan, Ozan; Sterman, George

    2017-06-01

    We develop a coordinate version of light-cone-ordered perturbation theory, for general time-ordered products of fields, by carrying out integrals over one light-cone coordinate for each interaction vertex. The resulting expressions depend on the lengths of paths, measured in the same light-cone coordinate. Each path is associated with a denominator equal to a "light-cone deficit," analogous to the "energy deficits" of momentum-space time- or light-cone-ordered perturbation theory. In effect, the role played by intermediate states in momentum space is played by paths between external fields in coordinate space. We derive a class of identities satisfied by coordinate diagrams, from which their imaginary parts can be derived. Using scalar QED as an example, we show how the eikonal approximation arises naturally when the external points in a Green function approach the light cone, and we give applications to products of Wilson lines. Although much of our discussion is directed at massless fields in four dimensions, we extend the formalism to massive fields and dimensional regularization.

  6. Path Models of Vocal Emotion Communication.

    Directory of Open Access Journals (Sweden)

    Tanja Bänziger

    Full Text Available We propose to use a comprehensive path model of vocal emotion communication, encompassing encoding, transmission, and decoding processes, to empirically model data sets on emotion expression and recognition. The utility of the approach is demonstrated for two data sets from two different cultures and languages, based on corpora of vocal emotion enactment by professional actors and emotion inference by naïve listeners. Lens model equations, hierarchical regression, and multivariate path analysis are used to compare the relative contributions of objectively measured acoustic cues in the enacted expressions and subjective voice cues as perceived by listeners to the variance in emotion inference from vocal expressions for four emotion families (fear, anger, happiness, and sadness. While the results confirm the central role of arousal in vocal emotion communication, the utility of applying an extended path modeling framework is demonstrated by the identification of unique combinations of distal cues and proximal percepts carrying information about specific emotion families, independent of arousal. The statistical models generated show that more sophisticated acoustic parameters need to be developed to explain the distal underpinnings of subjective voice quality percepts that account for much of the variance in emotion inference, in particular voice instability and roughness. The general approach advocated here, as well as the specific results, open up new research strategies for work in psychology (specifically emotion and social perception research and engineering and computer science (specifically research and development in the domain of affective computing, particularly on automatic emotion detection and synthetic emotion expression in avatars.

  7. Isosynchronous paths on a rotating surface

    CERN Document Server

    Ashby, Neil

    2014-01-01

    In special relativity, clock networks may be self-consistently synchronized in an inertial frame by slowly transporting clocks, or by exchanging electromagnetic signals between network nodes. However, clocks at rest in a rotating coordinate system--such as on the surface of the rotating earth--cannot be self-consistently synchronized by such processes, due to the Sagnac effect. Discrepancies that arise are proportional to the area swept out by a vector from the rotation axis to the portable clock or electromagnetic pulse, projected onto a plane normal to the rotation axis. This raises the question whether paths of minimal or extremal length can be found, for which the Sagnac discrepancies are zero. This paper discusses the variational problem of finding such "isosynchronous" paths on rotating discs and rotating spheres. On a disc, the problem resembles the classical isoperimetric problem and the paths turn out to be circular arcs. On a rotating sphere, however, between any two endpoints there are an infinite ...

  8. Purely geometric path integral for spin foams

    CERN Document Server

    Shirazi, Atousa Chaharsough

    2013-01-01

    Spin-foams are a proposal for defining the dynamics of loop quantum gravity via path integral. In order for a path integral to be at least formally equivalent to the corresponding canonical quantization, at each point in the space of histories it is important that the integrand have not only the correct phase -- a topic of recent focus in spin-foams -- but also the correct modulus, usually referred to as the measure factor. The correct measure factor descends from the Liouville measure on the reduced phase space, and its calculation is a task of canonical analysis. The covariant formulation of gravity from which spin-foams are derived is the Plebanski-Holst formulation, in which the basic variables are a Lorentz connection and a Lorentz-algebra valued two-form, called the Plebanski two-form. However, in the final spin-foam sum, one sums over only spins and intertwiners, which label eigenstates of the Plebanski two-form alone. The spin-foam sum is therefore a discretized version of a Plebanski-Holst path integ...

  9. Path integrals for dimerized quantum spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Foussats, Adriana, E-mail: afoussats@gmail.co [Facultad de Ciencias Exactas, Ingenieria y Agrimensura and Instituto de Fisica Rosario (UNR-CONICET), Av. Pellegrini 250, 2000 Rosario (Argentina); Greco, Andres [Facultad de Ciencias Exactas, Ingenieria y Agrimensura and Instituto de Fisica Rosario (UNR-CONICET), Av. Pellegrini 250, 2000 Rosario (Argentina); Muramatsu, Alejandro [Institut fuer Theoretische Physik III, Universitaet Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart (Germany)

    2011-01-11

    Dimerized quantum spin systems may appear under several circumstances, e.g. by a modulation of the antiferromagnetic exchange coupling in space, or in frustrated quantum antiferromagnets. In general, such systems display a quantum phase transition to a Neel state as a function of a suitable coupling constant. We present here two path-integral formulations appropriate for spin S=1/2 dimerized systems. The first one deals with a description of the dimers degrees of freedom in an SO(4) manifold, while the second one provides a path-integral for the bond-operators introduced by Sachdev and Bhatt. The path-integral quantization is performed using the Faddeev-Jackiw symplectic formalism for constrained systems, such that the measures and constraints that result from the algebra of the operators is provided in both cases. As an example we consider a spin-Peierls chain, and show how to arrive at the corresponding field-theory, starting with both an SO(4) formulation and bond-operators.

  10. Free path lengths in quasi crystals

    CERN Document Server

    Wennberg, Bernt

    2012-01-01

    The Lorentz gas is a model for a cloud of point particles (electrons) in a distribution of scatterers in space. The scatterers are often assumed to be spherical with a fixed diameter $d$, and the point particles move with constant velocity between the scatterers, and are specularly reflected when hitting a scatterer. There is no interaction between point particles. An interesting question concerns the distribution of free path lengths, i.e. the distance a point particle moves between the scattering events, and how this distribution scales with scatterer diameter, scatterer density and the distribution of the scatterers. It is by now well known that in the so-called Boltzmann-Grad limit, a Poisson distribution of scatters leads to an exponential distribution of free path lengths, whereas if the scatterer distribution is periodic, the distribution of free path behaves asymptotically like a Cauchy distribution. This paper considers the case when the scatters are distributed on a quasi crystal, i.e. non periodica...

  11. Analyzing Complex Reaction Mechanisms Using Path Sampling.

    Science.gov (United States)

    van Erp, Titus S; Moqadam, Mahmoud; Riccardi, Enrico; Lervik, Anders

    2016-11-08

    We introduce an approach to analyze collective variables (CVs) regarding their predictive power for a reaction. The method is based on already available path sampling data produced by, for instance, transition interface sampling or forward flux sampling, which are path sampling methods used for efficient computation of reaction rates. By a search in CV space, a measure of predictiveness can be optimized and, in addition, the number of CVs can be reduced using projection operations which keep this measure invariant. The approach allows testing hypotheses on the reaction mechanism but could, in principle, also be used to construct the phase-space committor surfaces without the need of additional trajectory sampling. The procedure is illustrated for a one-dimensional double-well potential, a theoretical model for an ion-transfer reaction in which the solvent structure can lower the barrier, and an ab initio molecular dynamics study of water auto-ionization. The analysis technique enhances the quantitative interpretation of path sampling data which can provide clues on how chemical reactions can be steered in desired directions.

  12. Path integral quantization of parametrised field theory

    CERN Document Server

    Varadarajan, M

    2004-01-01

    Free scalar field theory on a flat spacetime can be cast into a generally covariant form known as parametrised field theory in which the action is a functional of the scalar field as well as the embedding variables which describe arbitrary, in general curved, foliations of the flat spacetime. We construct the path integral quantization of parametrised field theory in order to analyse issues at the interface of quantum field theory and general covariance in a path integral context. We show that the measure in the Lorentzian path integral is non-trivial and is the analog of the Fradkin- Vilkovisky measure for quantum gravity. We construct Euclidean functional integrals in the generally covariant setting of parametrised field theory using key ideas of Schleich and show that our constructions imply the existence of non-standard `Wick rotations' of the standard free scalar field 2 point function. We develop a framework to study the problem of time through computations of scalar field 2 point functions. We illustra...

  13. All new custom path photo book creation

    Science.gov (United States)

    Wang, Wiley; Muzzolini, Russ

    2012-03-01

    In this paper, we present an all new custom path to allow consumers to have full control to their photos and the format of their books, while providing them with guidance to make their creation fast and easy. The users can choose to fully automate the initial creation, and then customize every page. The system manage many design themes along with numerous design elements, such as layouts, backgrounds, embellishments and pattern bands. The users can also utilize photos from multiple sources including their computers, Shutterfly accounts, Shutterfly Share sites and Facebook. The users can also use a photo as background, add, move and resize photos and text - putting what they want where they want instead of being confined to templates. The new path allows users to add embellishments anywhere in the book, and the high-performance platform can support up to 1,000 photos per book and up to 25 pictures per page. The path offers either Smart Autofill or Storyboard features allowing customers to populate their books with photos so they can add captions and customize the pages.

  14. Discovering Attack Path Oriented-IP Traceback

    Institute of Scientific and Technical Information of China (English)

    Fu Jianming(傅建明); Zhu Fuxi; Peng Guojun

    2003-01-01

    The technique of IP traceback may effectively block DOS (Denial Of Service) and meet the requirement of the computer forensic, but its accuracy depends upon that condition that each node in the Internet must support IP packet marking or detected agents. So far, this requirement is not satisfied. On the basis of traditional traceroute,this paper investigates the efficiency of discovering path methods from aspects of the size and order of detecting packets, and the length of paths.It points out that the size of padding in probed packets has a slight effect on discovering latency, and the latency with the method of bulk sending-receiving is much smaller than one with the traditional traceroute. Moreover, the loss rate of packets with the technique of TTL (Time To Live) which increases monotonously is less than that with the technique of TTL which decreases monotonously. Lastly,OS (Operating System) passive fingerprint is used as heuristic to predict the length of the discovered path so as to reduce disturbance in network traffic.

  15. Auditory perception of motor vehicle travel paths.

    Science.gov (United States)

    Ashmead, Daniel H; Grantham, D Wesley; Maloff, Erin S; Hornsby, Benjamin; Nakamura, Takabun; Davis, Timothy J; Pampel, Faith; Rushing, Erin G

    2012-06-01

    These experiments address concerns that motor vehicles in electric engine mode are so quiet that they pose a risk to pedestrians, especially those with visual impairments. The "quiet car" issue has focused on hybrid and electric vehicles, although it also applies to internal combustion engine vehicles. Previous research has focused on detectability of vehicles, mostly in quiet settings. Instead, we focused on the functional ability to perceive vehicle motion paths. Participants judged whether simulated vehicles were traveling straight or turning, with emphasis on the impact of background traffic sound. In quiet, listeners made the straight-or-turn judgment soon enough in the vehicle's path to be useful for deciding whether to start crossing the street. This judgment is based largely on sound level cues rather than the spatial direction of the vehicle. With even moderate background traffic sound, the ability to tell straight from turn paths is severely compromised. The signal-to-noise ratio needed for the straight-or-turn judgment is much higher than that needed to detect a vehicle. Although a requirement for a minimum vehicle sound level might enhance detection of vehicles in quiet settings, it is unlikely that this requirement would contribute to pedestrian awareness of vehicle movements in typical traffic settings with many vehicles present. The findings are relevant to deliberations by government agencies and automobile manufacturers about standards for minimum automobile sounds and, more generally, for solutions to pedestrians' needs for information about traffic, especially for pedestrians with sensory impairments.

  16. Path Models of Vocal Emotion Communication.

    Science.gov (United States)

    Bänziger, Tanja; Hosoya, Georg; Scherer, Klaus R

    2015-01-01

    We propose to use a comprehensive path model of vocal emotion communication, encompassing encoding, transmission, and decoding processes, to empirically model data sets on emotion expression and recognition. The utility of the approach is demonstrated for two data sets from two different cultures and languages, based on corpora of vocal emotion enactment by professional actors and emotion inference by naïve listeners. Lens model equations, hierarchical regression, and multivariate path analysis are used to compare the relative contributions of objectively measured acoustic cues in the enacted expressions and subjective voice cues as perceived by listeners to the variance in emotion inference from vocal expressions for four emotion families (fear, anger, happiness, and sadness). While the results confirm the central role of arousal in vocal emotion communication, the utility of applying an extended path modeling framework is demonstrated by the identification of unique combinations of distal cues and proximal percepts carrying information about specific emotion families, independent of arousal. The statistical models generated show that more sophisticated acoustic parameters need to be developed to explain the distal underpinnings of subjective voice quality percepts that account for much of the variance in emotion inference, in particular voice instability and roughness. The general approach advocated here, as well as the specific results, open up new research strategies for work in psychology (specifically emotion and social perception research) and engineering and computer science (specifically research and development in the domain of affective computing, particularly on automatic emotion detection and synthetic emotion expression in avatars).

  17. Adaptive path planning: Algorithm and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pang C.

    1995-03-01

    To address the need for a fast path planner, we present a learning algorithm that improves path planning by using past experience to enhance future performance. The algorithm relies on an existing path planner to provide solutions difficult tasks. From these solutions, an evolving sparse work of useful robot configurations is learned to support faster planning. More generally, the algorithm provides a framework in which a slow but effective planner may be improved both cost-wise and capability-wise by a faster but less effective planner coupled with experience. We analyze algorithm by formalizing the concept of improvability and deriving conditions under which a planner can be improved within the framework. The analysis is based on two stochastic models, one pessimistic (on task complexity), the other randomized (on experience utility). Using these models, we derive quantitative bounds to predict the learning behavior. We use these estimation tools to characterize the situations in which the algorithm is useful and to provide bounds on the training time. In particular, we show how to predict the maximum achievable speedup. Additionally, our analysis techniques are elementary and should be useful for studying other types of probabilistic learning as well.

  18. A Note on the Stochastic Nature of Feynman Quantum Paths

    Science.gov (United States)

    L. Botelho, Luiz C.

    2016-06-01

    We propose a Fresnel stochastic white noise framework to analyze the stochastic nature of the Feynman paths entering on the Feynman Path Integral expression for the Feynman Propagator of a particle quantum mechanically moving under a time-independent potential.

  19. A Note on the Stochastic Nature of Feynman Quantum Paths

    Science.gov (United States)

    Botelho, Luiz C. L.

    2016-11-01

    We propose a Fresnel stochastic white noise framework to analyze the stochastic nature of the Feynman paths entering on the Feynman Path Integral expression for the Feynman Propagator of a particle quantum mechanically moving under a time-independent potential.

  20. The Human Space Life Sciences Critical Path Roadmap Project: A Strategy for Human Space Flight through Exploration-Class Missions

    Science.gov (United States)

    Sawin, Charles F.

    1999-01-01

    The product of the critical path roadmap project is an integrated strategy for mitigating the risks associated with human exploration class missions. It is an evolving process that will assure the ability to communicate the integrated critical path roadmap. Unlike previous reports, this one will not sit on a shelf - it has the full support of the JSC Space and Life Sciences Directorate (SA) and is already being used as a decision making tool (e.g., budget and investigation planning for Shuttle and Space Station mission). Utility of this product depends on many efforts, namely: providing the required information (completed risk data sheets, critical question information, technology data). It is essential to communicate the results of the critical path roadmap to the scientific community - this meeting is a good opportunity to do so. The web site envisioned for the critical path roadmap will provide the capability to communicate to a broader community and to track and update the system routinely.

  1. Effect of Loading Paths on HydroformingTubular Square Components

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of loading path on tube hydroforming process is discussed in this paper with finiteelement simulation. Four different loading paths are utilized in simulating the forming process of square tubular component with hydroforming and the result of different loading path is presented. Among the result, the thickness distribution of bilinear loading path is the most uniform one. It shows that the increase of punch displacement in the stage of high pressure is beneficial to the forming of component for optimized stress condition.

  2. Inversion of signature for paths of bounded variation

    CERN Document Server

    Lyons, Terry

    2011-01-01

    We develop two methods to reconstruct a path of bounded variation from its signature. The first method gives a simple and explicit expression of any axis path in terms of its signature, but it does not apply directlty to more general ones. The second method, based on an approximation scheme, recovers any tree-reduced path from its signature as the limit of a uniformly convergent sequence of lattice paths.

  3. A Tool Path Generation Strategy for Sculptured Surfaces Machining

    Institute of Scientific and Technical Information of China (English)

    Chen Tao; Zhong Yifang; Zhou Ji

    2001-01-01

    This paper presents a strategy to generate interference-free tool paths for machiningsculptured surfaces. The strategy proposed here is first to determine the tool path topology. Thevalues of the step length and the path interval are then calculated based on the machining tolerancerequirements. After detecting and eliminating the tool interference, the interference-free tool path isgenerated. The effectiveness of the developed algorithm is demonstrated through simulation andactual cutting tests.

  4. A Flight-Path Control of Aircraft Based on Required Acceleration Vector

    Science.gov (United States)

    Yoshitani, Naoharu

    This paper presents an automatic flight-path control of aircraft. In the control, a desired flight trajectory is first determined as a sequence of straight lines, arcs and spirals in the three-dimensional space. Commands and command rates of heading and flight-path (climb) angles are then obtained from the desired trajectory. A required acceleration vector of the aircraft is calculated based on the command rates and angle deviations. Desired roll, pitch and yaw rates are then obtained by acceleration controller and are fed to attitude control. The feedback control of acceleration employs conventional PID control technology, without using inverse dynamics of the aircraft, and the attitude control can employ any existing control technologies suitable for the aircraft to be controlled. These make the proposed control relatively simple and easy to implement. Numerical simulations illustrate the effectiveness of the control.

  5. K shortest paths in stochastic time-dependent networks

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Pretolani, Daniele; Andersen, Kim Allan

    2004-01-01

    , finding the a priori shortest path is NP-hard, while the best time-adaptive strategy can be found in polynomial time. In this paper, we propose a solution method for the a priori shortest path problem, and we show that it can be easily adapted to the ranking of the first K shortest paths. Moreover, we...

  6. 14 CFR 25.115 - Takeoff flight path.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Takeoff flight path. 25.115 Section 25.115... STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.115 Takeoff flight path. (a) The takeoff flight path shall be considered to begin 35 feet above the takeoff surface at the end of the...

  7. Sub-optimality analysis of mobile robot rolling path planning

    Institute of Scientific and Technical Information of China (English)

    张纯刚; 席裕庚

    2003-01-01

    Rolling planning is an efficient method for path planning in uncertain environment. In this paper, the general principle and algorithm of mobile robot path planning based on rolling windows are studied. The sub-optimality of rolling path planning is analyzed in details and explained with a concrete example.

  8. Generating Approximative Minimum Length Paths in 3D for UAVs

    DEFF Research Database (Denmark)

    Schøler, Flemming; la Cour-Harbo, Anders; Bisgaard, Morten

    2012-01-01

    We consider the challenge of planning a minimum length path from an initial position to a desired position for a rotorcraft. The path is found in a 3-dimensional Euclidean space containing a geometric obstacle. We base our approach on visibility graphs which have been used extensively for path pl...

  9. Ranking shortest paths in Stochastic time-denpendent networks

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund; Andersen, Kim Allan; Pretolani, Daniele

    , finding the a priori shortest path is NP-hard, while the best time-adaptive strategy can be found in polynomial time. In this paper, we propose a solution method for the a priori shortest path problem, and we show that it can be easily adapted to the ranking of the first K shortest paths. Moreover, we...

  10. Perspectives on an alternative career path in regulatory science

    OpenAIRE

    Fields, F. Owen

    2013-01-01

    Perspectives are provided on an alternative career path in regulatory science for those currently involved in basic biology research. This path is compared and contrasted with basic research, and factors to be examined if one is considering such a path are discussed.

  11. Perspectives on an alternative career path in regulatory science.

    Science.gov (United States)

    Fields, F Owen

    2013-07-01

    Perspectives are provided on an alternative career path in regulatory science for those currently involved in basic biology research. This path is compared and contrasted with basic research, and factors to be examined if one is considering such a path are discussed.

  12. Time optimal paths for a constant speed unicycle

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.

    1991-01-01

    This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed unicycle. The time optimal paths consist of sequences of arcs of circles and straight lines. The maximum principle introduced concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. 10 refs., 6 figs.

  13. Path finding on high-dimensional free energy landscapes

    NARCIS (Netherlands)

    Díaz Leines, G.; Ensing, B.

    2012-01-01

    We present a method for determining the average transition path and the free energy along this path in the space of selected collective variables. The formalism is based upon a history-dependent bias along a flexible path variable within the metadynamics framework but with a trivial scaling of the

  14. Generating Approximative Minimum Length Paths in 3D for UAVs

    DEFF Research Database (Denmark)

    Schøler, Flemming; la Cour-Harbo, Anders; Bisgaard, Morten

    2012-01-01

    We consider the challenge of planning a minimum length path from an initial position to a desired position for a rotorcraft. The path is found in a 3-dimensional Euclidean space containing a geometric obstacle. We base our approach on visibility graphs which have been used extensively for path pl...

  15. Path-length-resolved optical Doppler perfusion monitoring

    NARCIS (Netherlands)

    Varghese, Babu; Rajan, Vinayakrishnan; Leeuwen, van Ton G.; Steenbergen, Wiendelt

    2007-01-01

    We report the first path-length-resolved perfusion measurements on human skin measured with a phase-modulated low-coherence Mach-Zehnder interferometer with spatially separated fibers for illumination and detection. Optical path lengths of Doppler shifted and unshifted light and path-length-dependen

  16. Astronomers Trace Microquasar's Path Back in Time

    Science.gov (United States)

    2003-01-01

    Astronomers have traced the orbit through our Milky Way Galaxy of a voracious neutron star and a companion star it is cannibalizing, and conclude that the pair joined more than 30 million years ago and probably were catapulted out of a cluster of stars far from the Galaxy's center. Path of Microquasar and Sun Path of Microquasar (red) and Sun (yellow) through the Milky Way Galaxy for the past 230 million years. Animations: GIF Version MPEG Version CREDIT: Mirabel & Rodrigues, NRAO/AUI/NSF The pair of stars, called Scorpius X-1, form a "microquasar," in which material sucked from the "normal" star forms a rapidly-rotating disk around the superdense neutron star. The disk becomes so hot it emits X-rays, and also spits out "jets" of subatomic particles at nearly the speed of light. Using precise positional data from the National Science Foundation's Very Long Baseline Array (VLBA) and from optical telescopes, Felix Mirabel, an astrophysicist at the Institute for Astronomy and Space Physics of Argentina and French Atomic Energy Commission, and Irapuan Rodrigues, also of the French Atomic Energy Commission, calculated that Scorpius X-1 is not orbiting the Milky Way's center in step with most other stars, but instead follows an eccentric path far above and below the Galaxy's plane. Scorpius X-1, discovered with a rocket-borne X-ray telescope in 1962, is about 9,000 light-years from Earth. It is the brightest continuous source of X-rays beyond the Solar System. The 1962 discovery and associated work earned a share of the 2002 Nobel Prize in physics for Riccardo Giacconi. Mirabel and Rodrigues used a number of published observations to calculate the path of Scorpius X-1 over the past few million years. "This is the most accurate determination we have made of the path of an X-ray binary," said Mirabel. By tracing the object's path backward in time, the scientists were able to conclude that the neutron star and its companion have been traveling together for more than 30

  17. An Efficient Multi-path Routing Algorithm Based on Hybrid Firefly Algorithm for Wireless Mesh Networks

    Directory of Open Access Journals (Sweden)

    K. Kumaravel

    2015-05-01

    Full Text Available Wireless Mesh Network (WMN uses the latest technology which helps in providing end users a high quality service referred to as the Internet’s “last mile”. Also considering WMN one of the most important technologies that are employed is multicast communication. Among the several issues routing which is significantly an important issue is addressed by every WMN technologies and this is done during the process of data transmission. The IEEE 802.11s Standard entails and sets procedures which need to be followed to facilitate interconnection and thus be able to devise an appropriate WMN. There has been introduction of several protocols by many authors which are mainly devised on the basis of machine learning and artificial intelligence. Multi-path routing may be considered as one such routing method which facilitates transmission of data over several paths, proving its capabilities as a useful strategy for achieving reliability in WMN. Though, multi-path routing in any manner cannot really guarantee deterministic transmission. As here there are multiple paths available for enabling data transmission from source to destination node. The algorithm that had been employed before in the studies conducted did not take in to consideration routing metrics which include energy aware metrics that are used for path selection during transferring of data. The following study proposes use of the hybrid multipath routing algorithm while taking in to consideration routing metrics which include energy, minimal loss for efficient path selection and transferring of data. Proposed algorithm here has two phases. In the first phase prim’s algorithm has been proposed so that in networks route discovery may be possible. For the second one the Hybrid firefly algorithm which is based on harmony search has been employed for selection of the most suitable and best through proper analysis of metrics which include energy awareness and minimal loss for every path that has

  18. A vision-based path planner/follower for an assistive robotics project

    OpenAIRE

    Cherubini, Andrea; Oriolo, Giuseppe; Macri, Francesco; Aloise, Fabio; Cincotti, Febo; Mattia, Donatella

    2007-01-01

    International audience; Assistive technology is an emerging area where robots can be used to help individuals with motor disabilities achieve independence in daily living activities. Mobile robots should be able to autonomously and safely move in the environment (e.g. the user apartment), by accurately solving the self-localization problem and planning ef paths to the target destination speciied by the user. This paper presents a vision-based navigation scheme designed for Sony AIBO, in ASPIC...

  19. Sensing and reconstruction of arbitrary light-in-flight paths by a relativistic imaging approach

    Science.gov (United States)

    Laurenzis, Martin; Klein, Jonathan; Bacher, Emmanuel; Metzger, Nicolas; Christnacher, Frank

    2016-10-01

    Transient light imaging is an emerging technology and interesting sensing approach for fundamental multidisciplinary research ranging from computer science to remote sensing. Recent developments in sensor technologies and computational imaging has made this emerging sensing approach a candidate for next generation sensor systems with rapidly increasing maturity but still relay on laboratory technology demonstrations. At ISL, transient light sensing is investigated by time correlated single photon counting (TCSPC). An eye-safe shortwave infrared (SWIR) TCSPC setup, consisting of an avalanche photodiode array and a pulsed fiber laser source, is used to investigate sparsely scattered light while propagating through air. Fundamental investigation of light in light are carried out with the aim to reconstruct the propagation path of arbitrary light paths. Light pulses are observed in light at various propagation angles and distances. As demonstrated, arbitrary light paths can be distinguished due to a relativistic effect leading to a distortion of temporal signatures. A novel method analyzing the time difference of arrival (TDOA) is carried out to determine the propagation angle and distance with respect to this relativistic effect. Based on our results, the performance of future laser warning receivers can be improved by the use of single photon counting imaging devices. They can detect laser light even when the laser does not directly hit the sensor or is passing at a certain distance.

  20. Analysis of construction dynamic plan using fuzzy critical path method

    Directory of Open Access Journals (Sweden)

    Kurij Kazimir V.

    2014-01-01

    Full Text Available Critical Path Method (CPM technique has become widely recognized as valuable tool for the planning and scheduling large construction projects. The aim of this paper is to present an analytical method for finding the Critical Path in the precedence network diagram where the duration of each activity is represented by a trapezoidal fuzzy number. This Fuzzy Critical Path Method (FCPM uses a defuzzification formula for trapezoidal fuzzy number and applies it on the total float (slack time for each activity in the fuzzy precedence network to find the critical path. The method presented in this paper is very effective in determining the critical activities and finding the critical paths.