WorldWideScience

Sample records for critical gen-iv systems

  1. Critical Issues on Materials for Gen-IV Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Caro, M; Marian, J; Martinez, E; Erhart, P

    2009-02-27

    Within the LDRD on 'Critical Issues on Materials for Gen-IV Reactors' basic thermodynamics of the Fe-Cr alloy and accurate atomistic modeling were used to help develop the capability to predict hardening, swelling and embrittlement using the paradigm of Multiscale Materials Modeling. Approaches at atomistic and mesoscale levels were linked to build-up the first steps in an integrated modeling platform that seeks to relate in a near-term effort dislocation dynamics to polycrystal plasticity. The requirements originated in the reactor systems under consideration today for future sources of nuclear energy. These requirements are beyond the present day performance of nuclear materials and calls for the development of new, high temperature, radiation resistant materials. Fe-Cr alloys with 9-12% Cr content are the base matrix of advanced ferritic/martensitic (FM) steels envisaged as fuel cladding and structural components of Gen-IV reactors. Predictive tools are needed to calculate structural and mechanical properties of these steels. This project represents a contribution in that direction. The synergy between the continuous progress of parallel computing and the spectacular advances in the theoretical framework that describes materials have lead to a significant advance in our comprehension of materials properties and their mechanical behavior. We took this progress to our advantage and within this LDRD were able to provide a detailed physical understanding of iron-chromium alloys microstructural behavior. By combining ab-initio simulations, many-body interatomic potential development, and mesoscale dislocation dynamics we were able to describe their microstructure evolution. For the first time in the case of Fe-Cr alloys, atomistic and mesoscale were merged and the first steps taken towards incorporating ordering and precipitation effects into dislocation dynamics (DD) simulations. Molecular dynamics (MD) studies of the transport of self

  2. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, D. W.; Kim, S. H.; Kim, W. G.; Kim, J. H.; Park, D. G.; Yoon, J. H.; Lee, H. Y.; Hing, J. H

    2005-08-15

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel.

  3. Overall system description and safety characteristics of Prototype Gen IV Sodium Cooled Fast Reactor in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Woon; Chang, Jin Wook; Lim, Jae Yong; Cheon, Jin Sik; Lee, Tae Ho; Kim, Sung Kyun; Lee, Kwi Lim; Joo, Hyung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The Prototype Gen IV sodium cooled fast reactor (PGSFR) has been developed for the last 4 years, fulfilling the technology demonstration of the burning capability of transuranic elements included in light water reactor spent nuclear fuel. The PGSFR design has been focused on the robustness of safety systems by enhancing inherent safety characteristics of metal fuel and strengthening passive safety features using natural circulation and thermal expansion. The preliminary safety information document as a major outcome of the first design phase of PGSFR development was issued at the end of 2015. The project entered the second design phase at the beginning of 2016. This paper summarizes the overall structures, systems, and components of nuclear steam supply system and safety characteristics of the PGSFR. The research and development activities to demonstrate the safety performance are also briefly introduced in the paper.

  4. Progress in the development of the neutron flux monitoring system of the French GEN-IV SFR: simulations and experimental validations [ANIMMA--2015-IO-98

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, C.; Filliatre, P.; De Izarra, G. [CEA, DEN, DER, Instrumentation, Sensors and Dosimetry Laboratory, Cadarache, F-13108 Saint-Paul-lez-Durance, (France); Elter, Zs.; Pazsit, I. [Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goteborg, (Sweden); Verma, V.; Hellesen, C.; Jacobsson, S. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala, (Sweden); Hamrita, H.; Bakkali, M. [CEA, DRT, LIST, Sensors and Electronic Architecture Laboratory, Saclay, F-91191 Gif Sur Yvette, (France); Chapoutier, N.; Scholer, A-C.; Verrier, D. [AREVA NP, 10 rue Juliette Recamier F-69456 Lyon, (France); Cantonnet, B.; Nappe, J-C. [PHONIS France S.A.S, Nuclear Instrumentation, Avenue Roger Roncier, B.P. 520, F-19106 Brive Cedex, (France); Molinie, P.; Dessante, P.; Hanna, R.; Kirkpatrick, M.; Odic, E. [Supelec, Department of Power and Energy System, F-91192 Gif Sur Yvette, (France); Jadot, F. [CEA, DEN, DER, ASTRID Project Group, Cadarache, F-13108 Saint-Paul-lez-Durance, (France)

    2015-07-01

    The neutron flux monitoring system of the French GEN-IV sodium-cooled fast reactor will rely on high temperature fission chambers installed in the reactor vessel and capable of operating over a wide-range neutron flux. The definition of such a system is presented and the technological solutions are justified with the use of simulation and experimental results. (authors)

  5. Gen IV Materials Handbook Implementation Plan

    Energy Technology Data Exchange (ETDEWEB)

    Rittenhouse, P.; Ren, W.

    2005-03-29

    A Gen IV Materials Handbook is being developed to provide an authoritative single source of highly qualified structural materials information and materials properties data for use in design and analyses of all Generation IV Reactor Systems. The Handbook will be responsive to the needs expressed by all of the principal government, national laboratory, and private company stakeholders of Gen IV Reactor Systems. The Gen IV Materials Handbook Implementation Plan provided here addresses the purpose, rationale, attributes, and benefits of the Handbook and will detail its content, format, quality assurance, applicability, and access. Structural materials, both metallic and ceramic, for all Gen IV reactor types currently supported by the Department of Energy (DOE) will be included in the Gen IV Materials Handbook. However, initial emphasis will be on materials for the Very High Temperature Reactor (VHTR). Descriptive information (e.g., chemical composition and applicable technical specifications and codes) will be provided for each material along with an extensive presentation of mechanical and physical property data including consideration of temperature, irradiation, environment, etc. effects on properties. Access to the Gen IV Materials Handbook will be internet-based with appropriate levels of control. Information and data in the Handbook will be configured to allow search by material classes, specific materials, specific information or property class, specific property, data parameters, and individual data points identified with materials parameters, test conditions, and data source. Details on all of these as well as proposed applicability and consideration of data quality classes are provided in the Implementation Plan. Website development for the Handbook is divided into six phases including (1) detailed product analysis and specification, (2) simulation and design, (3) implementation and testing, (4) product release, (5) project/product evaluation, and (6) product

  6. Gen IV Nuclear Energy Systems Interim Status Report on Pre-conceptual LFR Design Studies and Evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Halsey, W G; Brown, N W; Smith, C F; Sienicki, J J; Moisseytsev, A V; Kim, S J; Smith, M A; Yang, W S; Williamson, M; Li, N

    2005-02-09

    Previous pre-conceptual core neutronics and system thermal hydraulics calculations initiated the investigation of viability of a Small Secure Transportable Autonomous Reactor (SSTAR) lead-cooled small modular fast reactor concept.1 The calculations indicated that a single-phase natural circulation SSTAR reactor concept with good core reactor physics performance, good system thermal hydraulics performance, and a high Supercritical Carbon Dioxide (S-CO{sub 2}) Brayton cycle efficiency of 40 % may be viable at an electrical power of 18 MWe (45 MWt). Pre-conceptual studies of SSTAR viability have continued with the objective of improving the system thermal hydraulic performance and raising the plant efficiency as well as extending the neutronics analysis. This effort has been motivated by several considerations. First, the initial Pre-conceptual studies were focused upon a ''pancake'' core having a height-to-diameter of 0.5. It was found that a compact core with high average burn up could be realized with a height-to-diameter ratio of 0.8. Second, the initial assumed reactor vessel height of 12.2 meters limited the height of the Pb-to-CO{sub 2} in-reactor heat exchangers (HXs) which reduced the efficiency of supercritical carbon dioxide (S-CO2) Brayton cycle power converter. It was found that by increasing the reactor vessel height to 18 meters, the greater driving head for single-phase natural circulation would offset both the greater pressure drop of the 0.8 height-to-diameter ratio core as well as the pressure drop of taller HXs. This has enabled the plant efficiency to be increased from 40 to 43 % and the plant electrical power to be raised from 18 to 20 MWe. Third, reactivity feedback coefficients, which had previously not been generated for SSTAR, have now been calculated for the core. The reactivity feedback coefficients provide a basis for future investigation of the autonomous load following and passive shutdown behavior of the reactor. The

  7. Progress in the development of the neutron flux monitoring system of the French GEN-IV SFR: simulations and experimental validations [ANIMMA--2015-IO-392

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, C.; Filliatre, P.; Izarra, G. de [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Elter, Zs. [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goeteborg (Sweden); Verma, V. [CEA, DEN, Cadarache, Reactor Studies Department, 13108 Saint-Paul-lez-Durance (France); Uppsala University, Division of Applied Nuclear Physics, Box 516, SE-75120 Uppsala (Sweden); Hamrita, H.; Bakkali, M. [CEA, DRT, LIST, Metrology, Instrumentation and Information Department, Saclay, 91191 Gif-sur-Yvette (France); Chapoutier, N.; Scholer, A.C.; Verrier, D. [AREVA NP, 10 rue Juliette Recamier F-69456 Lyon (France); Hellesen, C.; Jacobsson, S. [Uppsala University, Division of Applied Nuclear Physics, Box 516, SE-75120 Uppsala (Sweden); Pazsit, I. [Chalmers University of Technology, Department of Applied Physics, Division of Nuclear Engineering, SE-412 96 Goeteborg (Sweden); Cantonnet, B.; Nappe, J.C. [PHOTONIS France, Nuclear Instrumentation, 19100 Brive-la-Gaillarde (France); Molinie, P.; Dessante, P.; Hanna, R.; Kirkpatrick, M.; Odic, E. [Supelec, Energy Department, 3 rue Joliot-Curie, 91191 Gif-sur-Yvette (France)

    2015-07-01

    France has a long experience of about 50 years in designing, building and operating sodium-cooled fast reactors (SFR) such as RAPSODIE, PHENIX and SUPER PHENIX. Fast reactors feature the double capability of reducing nuclear waste and saving nuclear energy resources by burning actinides. Since this reactor type is one of those selected by the Generation IV International Forum, the French government asked, in the year 2006, CEA, namely the French Alternative Energies and Atomic Energy Commission, to lead the development of an innovative GEN-IV nuclear- fission power demonstrator. The major objective is to improve the safety and availability of an SFR. The neutron flux monitoring (NFM) system of any reactor must, in any situation, permit both reactivity control and power level monitoring from startup to full power. It also has to monitor possible changes in neutron flux distribution within the core region in order to prevent any local melting accident. The neutron detectors will have to be installed inside the reactor vessel because locations outside the vessel will suffer from severe disadvantages; radially the neutron shield that is also contained in the reactor vessel will cause unacceptable losses in neutron flux; below the core the presence of a core-catcher prevents from inserting neutron guides; and above the core the distance is too large to obtain decent neutron signals outside the vessel. Another important point is to limit the number of detectors placed in the vessel in order to alleviate their installation into the vessel. In this paper, we show that the architecture of the NFM system will rely on high-temperature fission chambers (HTFC) featuring wide-range flux monitoring capability. The definition of such a system is presented and the justifications of technological options are brought with the use of simulation and experimental results. Firstly, neutron-transport calculations allow us to propose two in-vessel regions, namely the above-core and under

  8. Structural materials for Gen-IV nuclear reactors: Challenges and opportunities

    Science.gov (United States)

    Murty, K. L.; Charit, I.

    2008-12-01

    Generation-IV reactor design concepts envisioned thus far cater toward a common goal of providing safer, longer lasting, proliferation-resistant and economically viable nuclear power plants. The foremost consideration in the successful development and deployment of Gen-IV reactor systems is the performance and reliability issues involving structural materials for both in-core and out-of-core applications. The structural materials need to endure much higher temperatures, higher neutron doses and extremely corrosive environment, which are beyond the experience of the current nuclear power plants. Materials under active consideration for use in different reactor components include various ferritic/martensitic steels, austenitic stainless steels, nickel-base superalloys, ceramics, composites, etc. This paper presents a summary of various Gen-IV reactor concepts, with emphasis on the structural materials issues depending on the specific application areas. This paper also discusses the challenges involved in using the existing materials under both service and off-normal conditions. Tasks become increasingly complex due to the operation of various fundamental phenomena like radiation-induced segregation, radiation-enhanced diffusion, precipitation, interactions between impurity elements and radiation-produced defects, swelling, helium generation and so forth. Further, high temperature capability (e.g. creep properties) of these materials is a critical, performance-limiting factor. It is demonstrated that novel alloy and microstructural design approaches coupled with new materials processing and fabrication techniques may mitigate the challenges, and the optimum system performance may be achieved under much demanding conditions.

  9. Gen IV Materials Handbook Functionalities and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2009-12-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  10. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    Directory of Open Access Journals (Sweden)

    Lap-Yan Cheng

    2009-01-01

    Full Text Available The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR in a GEN IV direct-cycle gas-cooled fast reactor (GFR which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  11. Modelling of advanced structural materials for GEN IV reactors

    Science.gov (United States)

    Samaras, M.; Hoffelner, W.; Victoria, M.

    2007-09-01

    The choice of suitable materials and the assessment of long-term materials damage are key issues that need to be addressed for the safe and reliable performance of nuclear power plants. Operating conditions such as high temperatures, irradiation and a corrosive environment degrade materials properties, posing the risk of very expensive or even catastrophic plant damage. Materials scientists are faced with the scientific challenge to determine the long-term damage evolution of materials under service exposure in advanced plants. A higher confidence in life-time assessments of these materials requires an understanding of the related physical phenomena on a range of scales from the microscopic level of single defect damage effects all the way up to macroscopic effects. To overcome lengthy and expensive trial-and-error experiments, the multiscale modelling of materials behaviour is a promising tool, bringing new insights into the fundamental understanding of basic mechanisms. This paper presents the multiscale modelling methodology which is taking root internationally to address the issues of advanced structural materials for Gen IV reactors.

  12. A preliminary safety analysis for the prototype Gen IV Sodium-Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwi Lim; Ha, Kwi Seok; Jeong, Jae Ho; Choi, Chi Woong; Jeong, Tae Kyeong; Ahn, Sang June; Lee, Seung Won; Chang, Won Pyo; Kang, Seok Hun; Yoo, Jae Woon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Korea Atomic Energy Research Institute has been developing a pool-type sodium-cooled fast reactor of the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR). To assess the effectiveness of the inherent safety features of the PGSFR, the system transients during design basis accidents and design extended conditions are analyzed with MARS-LMR and the subchannel blockage events are analyzed with MATRA-LMR-FB. In addition, the in-vessel source term is calculated based on the super-safe, small, and simple reactor methodology. The results show that the PGSFR meets safety acceptance criteria with a sufficient margin during the events and keeps accidents from deteriorating into more severe accidents.

  13. A Virtual Reality Framework to Optimize Design, Operation and Refueling of GEN-IV Reactors.

    Energy Technology Data Exchange (ETDEWEB)

    Rizwan-uddin; Nick Karancevic; Stefano Markidis; Joel Dixon; Cheng Luo; Jared Reynolds

    2008-04-23

    many GEN-IV candidate designs are currently under investigation. Technical issues related to material, safety and economics are being addressed at research laboratories, industry and in academia. After safety, economic feasibility is likely to be the most important crterion in the success of GEN-IV design(s). Lessons learned from the designers and operators of GEN-II (and GEN-III) reactors must play a vital role in achieving both safety and economic feasibility goals.

  14. Phase Stability under Irradiation of Precipitates and Solid Solutions in Model ALloys and in ODS Alloys Relevant for Gen IV

    Energy Technology Data Exchange (ETDEWEB)

    Arthur T. Motta; Robert C. Birtcher

    2007-10-17

    The overall objective of this program is to investigate the irradiation-altered phase stability of oxide precipitates in ODS steels and of model alloy solid solutions of associated systems. This information can be used to determine whether the favorable mechanical propertiies of these steels are maintained under irradiation, thus addressing one of the main materials research issues for this class of steels as identified by the GenIV working groups. The research program will also create fundamental understanding of the irradiation precipitation/dissolution problem by studying a "model" system in which the variables can be controlled and their effects understood individually.

  15. Thermal stability study for candidate stainless steels of GEN IV reactors

    Energy Technology Data Exchange (ETDEWEB)

    Simeg Veternikova, J., E-mail: jana.veternikova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Degmova, J. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pekarcikova, M. [Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, Paulinska 16, 917 24 Trnava (Slovakia); Simko, F. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia); Petriska, M. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Skarba, M. [Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mikula, P. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pupala, M. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia)

    2016-11-30

    Highlights: • Thermal resistance of advanced stainless steels were observed at 1000 °C. • GEN IV candidate steels were confronted to classic AISI steels. • ODS AISI 316 has weaker thermal resistance than classic AISI steel. • Ferritic ODS steels and NF 709 has better thermal resistance than AISI steels. - Abstract: Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  16. Gen IV Materials Handbook Beta Release for Structural and Functional Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Luttrell, Claire [ORNL

    2006-09-12

    Development of the Gen IV Materials Handbook is briefly summarized up to date. Current status of the Handbook website construction is described. The developed Handbook components and access control of the beta version are discussed for the present evaluation release. Detailed instructions and examples are given to provide guidance for evaluators to browse the constructed parts and use all the currently developed functionalities of the Handbook in evaluation.

  17. Conceptual Design on Primary Control Rod Drive Mechanism of a Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Koo, Gyeong Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    This paper describes the key concept of the drive mechanism, and suggests a required motor power and reducer gears to meet the functional design requirements, and a seismic response analysis of CRDM housing is performed to check its structural integrity. An AC servo motor is selected as a CRA driving power because it uses permanent magnets and is brushless type while DC motor needs a brush and a coil rotates. The control shim motor size is constrained by a housing diameter of 250mm. The driving system has several design requirements. To calculate the motor power, the drive shaft torque is needed. One part of the drive shaft has a lead screw, driving by a ball-nut. The ball screw driver torque (Tr) is calculated by some equations as follow; A servo motor with a nominal power of 100W, a nominal torque of 0.32 N-m (max. 0.48N-m) is selected considering a safety margin. Its diameter is about 50mm. The fast drive-in motor needs a strong power to insert enforcedly the stuck CRA into core within a required time. The motor sizes are calculated by the same procedure. The diameters are in the range of 80mm to 110mm by the insertion time (10 ∼ 24 seconds). The prototype Gen-IV SFR (sodium-cooled Fast Reactor) is of 150MWe capacity. The reactor has six primary control rod assemblies(CRAs). The primary control rod is used for power control, burn-up compensation and reactor shutdown in response to demands from the plant control or protection systems. The control rod drive mechanism (CRDM) consists of the drive motor assembly, the driveline, and its housing. The driveline consists of three concentric members of a drive shaft, a tension tube, and a position indicator rod, and it connects the drive motor assembly to the CRA. Main issue is that these many driving parts shall be enclosed within a limited housing diameter because the available pitch of CRDMs is limited by 300mm.

  18. Gen IV Materials Handbook Functionalities and Operation (2B) Handbook Version 2.0

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2011-08-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  19. Irradiation effects in oxide dispersion strengthened (ODS) Ni-base alloys for Gen. IV nuclear reactors

    Science.gov (United States)

    Oono, Naoko; Ukai, Shigeharu; Kondo, Sosuke; Hashitomi, Okinobu; Kimura, Akihiko

    2015-10-01

    Oxide particle dispersion strengthened (ODS) Ni-base alloys are irradiated by using simulation technique (Fe/He dual-ion irradiation) to investigate the reliability to Gen. IV high-temperature reactors. The fine oxide particles with less than 10 nm in average size and approximately 8.0 × 1022 m-3 in number density remained after 101 dpa irradiation. The tiny helium bubbles were inside grains, not at grain-boundaries; it is advantageous effect of oxide particles which trap the helium atoms at the particle-matrix interface. Ni-base ODS alloys demonstrated their great ability to overcome He embrittlement.

  20. Thermal stability study for candidate stainless steels of GEN IV reactors

    Science.gov (United States)

    Simeg Veternikova, J.; Degmova, J.; Pekarcikova, M.; Simko, F.; Petriska, M.; Skarba, M.; Mikula, P.; Pupala, M.

    2016-11-01

    Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  1. Gen IV Materials Handbook Functionalities and Operation (4A) Handbook Version 4.0

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL

    2013-09-01

    This document is prepared for navigation and operation of the Gen IV Materials Handbook, with architecture description and new user access initiation instructions. Development rationale and history of the Handbook is summarized. The major development aspects, architecture, and design principles of the Handbook are briefly introduced to provide an overview of its past evolution and future prospects. Detailed instructions are given with examples for navigating the constructed Handbook components and using the main functionalities. Procedures are provided in a step-by-step fashion for Data Upload Managers to upload reports and data files, as well as for new users to initiate Handbook access.

  2. Progress reports for Gen IV sodium fast reactor activities FY 2007.

    Energy Technology Data Exchange (ETDEWEB)

    Cahalan, J. E.; Tentner, A. M.; Nuclear Engineering Division

    2007-10-04

    identified as being for prevention of progression into severe accident conditions (prevention of core melting) or for mitigation of severe accident consequences (mitigation of the impact of core melting to protect public health and safety). Because design measures for severe accident prevention and mitigation are beyond the normal design basis, established regulatory guidelines and codes do not provide explicit identification of the design performance requirements for severe accident accommodation. The treatment of severe accidents is one of the key issues of R&D plans for the Gen IV systems in general, and for the Sodium Fast Reactor (SFR) in particular. Despite the lack of an unambiguous definition of safety approach applicable for severe accidents, there is an emerging consensus on the need for their consideration for the design. The US SFR program and Argonne National Laboratory (ANL) in particular have actively studied the potential scenarios and consequences of Hypothetical Core Disruptive Accidents (HCDA) for SFRs with oxide fuel during the Fast Flux Test Facility (FFTF) and Clinch River Breeder Reactor Plant (CRBRP) programs in the 70s and 80s. Later, the focus of the US SFR safety R&D activities shifted to the prevention of all HCDAs through passive safety features of the SFRs with metal fuel in the Integral Fast Reactor (IFR) program, and the study of severe accident consequences was de-emphasized. The goal of this paper is to provide an overview of the current SFR safety approach and the role of severe accidents in Japan and France, in preparation for an expected and more active collaboration in this area between the US, Japan, and France.

  3. Summary of Structural Concept Development and High Temperature Structural Integrity Evaluation Technology for a Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Han; Joo, Young Sang; Lee, Hyeong Yeon (and others)

    2008-04-15

    The economic improvement is a hot issue as one of Gen IV nuclear plant goals. It requires many researches and development works to meet the goal by securing the same level of plant safety. One of the key research items is the increase of the plant capacity with the minimum number of components and loops. Through the successful conceptual design experience for the KALIMER-600, the structural design study for a 1200MWe large capacity of sodium-cooled fast reactor has been performed to achieve the above plant size effects. The component number and reactor structural sizing were determined based on the core and fluid system design information. Several researches were performed to reduce the construction cost of NSSS in structural point of view, for example, a simplified component arrangement, concept proposals of integrated components, a high temperature LBB application technology, and an innovative in-service inspection (ISI) tool, and a computer program development of the ASME-NH design procedure of the class 1 structure and component under high temperature over 500 .deg. C. The IHTS piping arrangement was also proposed to minimize the length through the properly locating the SG and pump by 126m. Further studies of these concepts are required to confirm on the fabricability and the structural integrity for the operating and design loads. The proposed concepts will be optimized to a unified conceptual design through several trade-off studies.

  4. Microstructure stability of candidate stainless steels for Gen-IV SCWR fuel cladding application

    Science.gov (United States)

    Li, Jian; Zheng, W.; Penttilä, S.; Liu, P.; Woo, O. T.; Guzonas, D.

    2014-11-01

    In the past few years, significant progress has been made in materials selection for Gen-IV SCWR fuel cladding applications. Current studies indicate that austenite stainless steels such as 310H are promising candidates for in-core applications. Alloys in this group are promising for their corrosion resistance, SCC resistance, high temperature mechanical properties and creep resistance at temperatures up to 700 °C. However, one under-studied area of this alloy is the long-term microstructure stability under the proposed reactor operating condition. Unstable microstructure not only results in embrittlement but also has the potential to reduce their resistance to corrosion or stress-corrosion cracking. In this study, stainless steels 310H and 304H were tested for their SCWR corrosion resistance and microstructure stability.

  5. Mechanical Design Concept of Fuel Assembly for Prototype GEN-IV Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, K. H.; Lee, C. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The prototype GEN-IV sodium-cooled fast reactor (PGSFR) is an advanced fast reactor plant design that utilizes compact modular pool-type reactors sized to enable factory fabrication and an affordable prototype test for design certification at minimum cost and risk. The design concepts of the fuel assembly (FA) were introduced for a PGSFR. Unlike that for the pressurized water reactor, there is a neutron shielding concept in the FA and recycling metal fuel. The PGSFR core is a heterogeneous, uranium-10% zirconium (U-10Zr) metal alloy fuel design with 112 assemblies: 52 inner core fuel assemblies, 60 outer core fuel assemblies, 6 primary control assemblies, 3 secondary control assemblies, 90 reflector assemblies and 102 B4C shield assemblies. This configuration is shown in Fig. 1. The core is designed to produce 150 MWe with an average temperature rise of 155 .deg. C. The inlet temperature is 390 .deg. C and the bulk outlet temperature is 545 .deg. C. The core height is 900 mm and the gas plenum length is 1,250 mm. A mechanical design of a fuel assembly for a PGSFR was established. The mechanical design concepts are well realized in the design. In addition to this, the analytical and experimental works will be carries out for verifying the design soundness.

  6. Preliminary Safety Analysis of Anticipated Transient without Scram (ATWS) Events for the Prototype GEN-IV SFR (PGSFR) using MARS-LMR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Ha, Kwiseok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    A safety analysis of ATWS for the recently designed Prototype GEN-IV Sodium Cooled Fast Reactor (PGSFR) was conducted. Unprotected Transient Over-Power (UTOP), Unprotected Loss OF Flow (ULOF), and Unprotected Loss Of Heat Sink (ULOHS) were selected as representative events for the ATWS. In an unprotected condition, the power in the core is only controlled by reactivity feedbacks, which are interacted with the thermal-hydraulic characteristics of the components in the plant. Heat is removed by the steam generator (SG) and decay heat removal system (DHRS). Therefore, the major objectives of the safety analysis of the ATWS events are to investigate the thermal hydraulic characteristics of the DHRS and the SG, the neutron kinetic characteristics of the reactivity feedback, and the interaction between the neutron kinetics, and the thermal-hydraulics during the events.

  7. A Cylindrical Shielding Design Concept for the Prototype Gen-IV Sodium-cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sunghwan; Kim, Sang Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    In the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR), a metal fueled, blanket-free, pool type SFR concept is adopted to acquire the inherent safety characteristics and high proliferation-resistance. In the pool type fast reactor, the intermediate heat exchangers (IHXs), which transfer heat from the primary sodium pool to a secondary sodium loop, are placed inside of the reactor vessel. Hence, secondary sodium passing the IHXs can be radioactivated by a {sup 23}Na(n,g){sup 24}Na reaction, and radioactivated secondary sodium causes a significant dose in the Steam Generator Building (SGB). Therefore, a typical core of a pool type fast reactor is usually surrounded by a massive quantity of shields. In addition, the blanket composed of depleted uranium plays a role as superior shielding material; a significant increase in shields is required in the blanket-free pool type SFR. In this paper, a new cylindrical shielding design concept is proposed for a blanket-free pool type SFR. In a conventional shielding design, massive axial shields are required to prevent irradiation of secondary sodium passing IHXs and they should be replaced according to the subassembly replacement in spite of negligible depletion of the shielding material. The proposed shielding design concept minimizes the quantity of shields without their replacement. In this paper, a new cylindrical shielding design concept is proposed for a blanket-free pool type SFR such as a PGSFR. The proposed design concept satisfied the dose limit in the steam generator building successfully without introducing a large quantity of B{sub 4}C shielding inside the subassembly.

  8. On the safety and performance demonstration tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and validation and verification of computational codes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Jeong, Ji Young; Lee, Tae Ho; Kim, Sung Kyun; Euh, Dong Jin; Joo, Hyung Kook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR) has been developed and the validation and verification (V and V) activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1), produced satisfactory results, which were used for the computer codes V and V, and the performance test results of the model pump in sodium showed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs) have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

  9. Critical incident reporting systems.

    Science.gov (United States)

    Ahluwalia, Jag; Marriott, Lin

    2005-02-01

    Approximately 10% of all hospital admissions are complicated by critical incidents in which harm is caused to the patient - this amounts to more than 850,000 incidents annually. Critical incident reporting (CIR) systems refer to the structured reporting, collation and analysis of such incidents. This article describes the attributes required for an effective CIR system. Example neonatal trigger events and a management pathway for handling a critical incident report are described. The benefits and limitations of CIR systems, reactive and prospective approaches to the analysis of actual or potential critical incidents and the assessment of risk are also reviewed. Individual human error is but one contributor in the majority of critical incidents. Recognition of this and the fostering of an organisational culture that views critical incident reports as an opportunity to learn and to improve future patient care is vital if CIR systems are to be effective.

  10. On the Safety and Performance Demonstration Tests of Prototype Gen-IV Sodium-Cooled Fast Reactor and Validation and Verification of Computational Codes

    Directory of Open Access Journals (Sweden)

    Jong-Bum Kim

    2016-10-01

    Full Text Available The design of Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR has been developed and the validation and verification (V&V activities to demonstrate the system performance and safety are in progress. In this paper, the current status of test activities is described briefly and significant results are discussed. The large-scale sodium thermal-hydraulic test program, Sodium Test Loop for Safety Simulation and Assessment-1 (STELLA-1, produced satisfactory results, which were used for the computer codes V&V, and the performance test results of the model pump in sodium showed good agreement with those in water. The second phase of the STELLA program with the integral effect tests facility, STELLA-2, is in the detailed design stage of the design process. The sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger performance test, the intermediate heat exchanger test facility, and the test facility for the reactor flow distribution are underway. Flow characteristics test in subchannels of a wire-wrapped rod bundle has been carried out for safety analysis in the core and the dynamic characteristic test of upper internal structure has been performed for the seismic analysis model for the PGSFR. The performance tests for control rod assemblies (CRAs have been conducted for control rod drive mechanism driving parts and drop tests of the CRA under scram condition were performed. Finally, three types of inspection sensors under development for the safe operation of the PGSFR were explained with significant results.

  11. Uranium enrichment reduction in the Prototype Gen-IV sodium-cooled fast reactor (PGSFR) with PBO reflector

    Energy Technology Data Exchange (ETDEWEB)

    Hartanto, Donny; Kim, Chi Hyung; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2016-04-15

    The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR) is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

  12. Electromagnet Tests on Primary Control Rod Drive Mechanism of a Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaehan; Koo, Gyeonghoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The primary control system is used for power control, burn-up compensation and reactor shutdown in response to demands from the plant control or protection systems. This paper describes the lifting and holding force tests of the electromagnetic equipment of a primary control rod drive mechanism (CRDM). The supply currents above 1.5 A and 15A on coil are required for holding the CRA with a 1mm gap, and lifting the CRA with 10mm gap, respectively. The currents cover all the loads to be expected in driveline. The S10C carbon steel can be replaced with the SS410 stainless steel by increasing the supply current about 30%. The assist spring, pushing down the tension tube with a compressed force, plays an important role when the operation load is smaller than 20kgf. The spring force can cease a time delay on the free drop of the tension tube carrying a light driving mass because a residual electromagnetic force may exist for a while even though the supply power is cut off. The holding current can be reduced by closing the gap size of 1mm between inner core and armature.

  13. Millimeter-Wave Thermal Analysis Development and Application to GEN IV Reactor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Wosko, Paul; Sundram, S. K.

    2012-10-16

    New millimeter-wave thermal analysis instrumentation has been developed and studied for characterization of materials required for diverse fuel and structural needs in high temperature reactor environments such as the Next Generation Nuclear Plant (NGNP). A two-receiver 137 GHz system with orthogonal polarizations for anisotropic resolution of material properties has been implemented at MIT. The system was tested with graphite and silicon carbide specimens at temperatures up to 1300 ºC inside an electric furnace. The analytic and hardware basis for active millimeter-wave radiometry of reactor materials at high temperature has been established. Real-time, non contact measurement sensitivity to anisotropic surface emissivity and submillimeter surface displacement was demonstrated. The 137 GHz emissivity of reactor grade graphite (NBG17) from SGL Group was found to be low, ~ 5 %, in the 500 – 1200 °C range and increases by a factor of 2 to 4 with small linear grooves simulating fracturing. The low graphite emissivity would make millimeter-wave active radiometry a sensitive diagnostic of graphite changes due to environmentally induced stress fracturing, swelling, or corrosion. The silicon carbide tested from Ortek, Inc. was found to have a much higher emissivity at 137 GHz of ~90% Thin coatings of silicon carbide on reactor grade graphite supplied by SGL Group were found to be mostly transparent to millimeter-waves, increasing the 137 GHz emissivity of the coated reactor grade graphite to about ~14% at 1250 ºC.

  14. Development of the Plan for Improvement of the Competitiveness of KALIMER Design against the Competing Reactor Design in Gen IV

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Yoon Sub; Kim, Yeong Il; Hong, Ser Gi (and others)

    2005-11-15

    A fast reactor has a good transmutation capability and it enables breeding of fuel and use of a closed fuel cycle. By these characteristics of a fast reactor, the limited uranium resources of the world can be much more effectively utilized and the nuclear wastes of a high level of radioactivity and toxicity from the current nuclear power reactors of LWRs and HWRs can be drastically reduced in its volume and the management of the wastes can be easily treated. Also electricity can be generated more effectively since a fast reactor has the feature of high operation temperature. These features of a fast reactor makes it inevitable on a long term basis to construct fast reactors in Korea. The domestic fast reactor technology level, however, is at the level of coming out of a beginning stage and needs utilization of international expertise. Recently an international cooperation program called GIF has been formulated and our KALIMER was selected as one of the two reference designs for the international joint R and D works with JSFR of Japan. In the current frame of the GIF program, the two selected reference designs are supposed to be evaluated against each other in future and one design is to be finally selected. To make the international cooperation program directed more useful to our fast reactor technology development, it is required to strengthen the competitiveness of KALIMER so that it can be selected. To meet the necessity, a study was made to enhance the competitiveness of KALIMER. The design characteristics of JSFR was investigated and relatively weak points and strong points of KALIMER were identified. Also the GenIV SFR design requirements were applied to two designs to evaluate the level of requirements satisfaction. Based on these investigation results, a plan for improving the weak features and strengthening the strong points of the KALIMER design has been developed.

  15. Optimized, Competitive Supercritical-CO2 Cycle GFR for Gen IV Service

    Energy Technology Data Exchange (ETDEWEB)

    M.J. Driscoll; P. Hejzlar; G. Apostolakis

    2008-09-08

    An overall plant design was developed for a gas-cooled fast reactor employing a direct supercritical Brayton power conversion system. The most important findings were that (1) the concept could be capital-cost competitive, but startup fuel cycle costs are penalized by the low core power density, specified in large part to satisfy the goal of significatn post-accident passive natural convection cooling; (2) active decay heat removal is preferable as the first line of defense, with passive performance in a backup role; (3) an innovative tube-in-duct fuel assembly, vented to the primpary coolant, appears to be practicable; and (4) use of the S-Co2 GFR to support hydrogen production is a synergistic application, since sufficient energy can be recuperated from the product H2 and 02 to allow the electrolysis cell to run 250 C hotter than the reactor coolant, and the water boilers can be used for reactor decay heat removal. Increasing core poer density is identified as the top priority for future work on GFRs of this type.

  16. GEN IV: Carbide Fuel Elaboration for the 'Futurix Concepts' experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vaudez, Stephane; Riglet-Martial, Chantal; Paret, Laurent; Abonneau, Eric [Commissariat a l' Energie Atomique (C.E.A.), Direction de l' Energie Nucleaire, Centre d' Etudes de Cadarache, 13108 Saint Paul lez Durance Cedex (France)

    2008-07-01

    In order to collect information on the behaviour of the future GFR (Gas Fast Reactor) fuel under fast neutron irradiation, an experimental irradiation program, called 'Futurix-concepts' has been launched at the CEA. The considered concept is a composite material made of a fissile fuel embedded in an inert ceramic matrix. Fissile fuel pellets are made of UPuN or UPuC while ceramics are SiC for the carbide fuel and TiN for the nitride fuel. This paper focuses on the description of the carbide composite fabrication. The UPuC pellets are manufactured using a metallurgical powder process. Fabrication and handling of the fuels are carried out in glove boxes under a nitrogen atmosphere. Carbide fuel is synthesized by carbo-thermic reduction under vacuum of a mixture of actinide oxide and graphitic carbon up to 1550 deg. C. After ball milling, the UPuC powder is pressed to create hexagonal or spherical compacts. They are then sintered up to 1750 deg. C in order to obtain a density of 85 % of the theoretical one. The sintered pellets are inserted into an inert and tight capsule of SiC. In order to control the gap between the fuel and the matrix precisely, the pellets are abraded. The inert matrix is then filled with the pellets and the whole system is sealed by a BRASiC{sup R} process at high temperature under a helium atmosphere. Fabrication of the sample to be irradiated was done in 2006 and the irradiation began in May 2007 in the Phenix reactor. This presentation will detail and discuss the results obtained during this fabrication phase. (authors)

  17. Analyses of Design Extended Condition Events for the Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Jeong, Taekyung; Lee, Kwilim; Jeong, Jaeho; Ha, Kwiseok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    In this study, the sensitivity tests are conducted. In the case of the UTOP event, a sensitivity test for the reactivity insertion amount and rate were conducted. This analysis can give a requirement for margin of control rod stop system (CRSS). For example, the CRSS in the PRISM designed based on the 0.4 $ reactivity insertion, which is analyzed with safety analysis of UTOP event. Moreover, the sensitivity tests for weighting factor in the core radial expansion reactivity feedback model were also carried out for all ATWS events. Currently, the reactivity feedback model for the PGSFR is not validated yet. However, the reactivity feedback models in the MARS-LMR are validating with various plant-based data including EBR-II SHRT. The ATWS events for the PGSFR classified in the design extended condition including UTOP, ULOF, and ULOHS are analyzed with MARS-LMR. In this study, the sensitivity tests for reactivity insertion amount and rate in the UTOP event are conducted. The reactivity insertion amount is obviously an influential parameter. The reactivity insertion amount can give a requirement for design of the CRSS, therefore, this sensitivity result is very important to the CRSS. In addition, sensitivity tests for the weighting factor in the radial expansion reactivity model are carried out. The weighting factor for a grid plate, W{sub GP}, which means contribution of feedback in the grid plate is changed for all unprotected events. The grid plate expansion is governed by a core inlet temperature. As the W{sub GP} is increased, the power in the UTOP and the ULOF is increased, however, the power in the ULOHS is decreased. The higher power during transient means lower reactivity feedback and smaller expansion. Thus, the core outlet temperature rise is dominant in the UTOP and ULOF events, however, the core inlet temperature rise is dominant in the ULOHS. Therefore, the grid plate expansion in the ULOHS is predominant.

  18. Sensitivity Tests for the Unprotected Events of the Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Chiwoong; Lee, Kwilim; Jeong, Jaeho; Yu, Jin; An, Sangjun; Lee, Seung Won; Chang, Wonpyo; Ha, Kwiseok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Unprotected Transient Over Power, (UTOP), Unprotected Loss Of Flow (ULOF), and Unprotected Loss Of Heat Sink (ULOHS) are selected as ATWS events. Among these accidents, the ULOF event shows the lowest clad temperature. However, the ULOHS event showed the highest peak clad temperature, due to the positive CRDL/RV expansion reactivity feedback and insufficient DHRS capacity. In this study, the sensitivity tests are conducted. In the case of the UTOP event, a sensitivity test for the reactivity insertion amount and rate were conducted. This analysis can give a requirement for margin of control rod stop system (CRSS). Currently, the reactivity feedback model for the PGSFR is not validated yet. However, the reactivity feedback models in the MARS-LMR are validating with various plant-based data including EBR-II SHRT. The ATWS events for the PGSFR classified in the design extended condition including UTOP, ULOF, and ULOHS are analyzed with MARS-LMR. In this study, the sensitivity tests for reactivity insertion amount and rate in the UTOP event are conducted. The reactivity insertion amount is obviously an influential parameter. The reactivity insertion amount can give a requirement for design of the CRSS, therefore, this sensitivity result is very important to the CRSS. In addition, sensitivity tests for the weighting factor in the radial expansion reactivity model are carried out. The weighting factor for a grid plate, W{sub GP}, which means contribution of feedback in the grid plate is changed for all unprotected events. The grid plate expansion is governed by a core inlet temperature. As the W{sub GP} is increased, the power in the UTOP and the ULOF is increased, however, the power in the ULOHS is decreased. The higher power during transient means lower reactivity feedback and smaller expansion. Thus, the core outlet temperature rise is dominant in the UTOP and ULOF events, however, the core inlet temperature rise is dominant in the ULOHS. Therefore, the grid plate

  19. Preliminary Design of Critical Function Monitoring System of PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    A PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor) is under development at Korea Atomic Energy Research Institute. A critical function monitoring system of the PGSFR is preliminarily studied. The functions of CFMS are to display critical plant variables related to the safety of the plant during normal and accident conditions and guide the operators corrective actions to keep the plant in a safe condition and mitigate the consequences of accidents. The minimal critical functions of the PGSFR are composed of reactivity control, reactor core cooling, reactor coolant system integrity, primary heat transfer system(PHTS) heat removal, sodium water reaction mitigation, radiation control and containment conditions. The variables and alarm legs of each critical function of the PGSFR are as follows; - Reactivity control: The variables of reactivity control function are power range neutron flux instrumentation, intermediate range neutron flux instrumentation, source range neutron flux instrumentation, and control rod bottom contacts. The alarm leg to display the reactivity controls consists of status of control drop malfunction, high post trip power and thermal reactivity addition. - Reactor core cooling: The variables are PHTS sodium level, hot pool temperature of PHTS, subassembly exit temperature, cold pool temperature of the PHTS, PHTS pump current, and PHTS pump breaker status. The alarm leg consists of high core delta temperature, low sodium level of the PHTS, high subassembly exit temperature, and low PHTS pump load. - Reactor coolant system integrity: The variables are PHTS sodium level, cover gas pressure, and safeguard vessel sodium level. The alarm leg is composed of low sodium level of PHTS, high cover gas pressure and high sodium level of the safety guard vessel. - PHTS heat removal: The variables are PHTS sodium level, hot pool temperature of PHTS, core exit temperature, cold pool temperature of the PHTS, flow rate of passive residual heat removal system

  20. An EBSD investigation on flow localization and microstructure evolution of 316L stainless steel for Gen IV reactor applications

    Science.gov (United States)

    Wu, Xianglin; Pan, Xiao; Mabon, James C.; Li, Meimei; Stubbins, James F.

    2007-09-01

    Type 316L stainless steel has been selected as a candidate structural material in a series of current accelerator driven systems and Generation IV reactor conceptual designs. The material is sensitive to irradiation damage in the temperature range of 150-400 °C: even low levels of irradiation exposure, as small as 0.1 dpa, can cause severe loss of ductility during tensile loading. This process, where the plastic flow becomes highly localized resulting in extremely low overall ductility, is referred as flow localization. The process controlling this confined flow is related to the difference between the yield and ultimate tensile strengths such that large irradiation-induced increases in the yield strength result in very limited plastic flow leading to necking after very small levels of uniform elongation. In this study, the microstructural evolution controlling flow localization is examined. It is found that twinning is an important deformation mechanism at lower temperatures since it promotes the strain hardening process. At higher temperatures, twinning becomes energetically impossible since the activation of twinning is determined by the critical twinning stress, which increases rapidly with temperature. Mechanical twinning and dislocation-based planar slip are competing mechanisms for plastic deformation.

  1. Critical Phenomena in Finite Systems

    CERN Document Server

    Bonasera, A; Chiba, S

    2001-01-01

    We discuss the dynamics of finite systems within molecular dynamics models. Signatures of a critical behavior are analyzed and compared to experimental data both in nucleus-nucleus and metallic cluster collisions. We suggest the possibility to explore the instability region via tunneling. In this way we can obtain fragments at very low temperatures and densities. We call these fragments quantum drops.

  2. Erp Systems Critical Success Factors

    Directory of Open Access Journals (Sweden)

    Islam K. Sowan

    2015-06-01

    Full Text Available The Enterprise Resources Planning (ERP systems are one of the highly complex systems in the information systems field; the implementations of this type of systems need a long time, high cost, and a lot of resources. Many factors affect the successful implementation of ERP system. The critical success factors (CSFs can be categorized as general, ICT related and software engineering or system life cycle (SLC related. This paper is a survey paper that identifies ERP systems CSFs in general and software engineering CSFs in specific. Also an agile methodology for ERP systems' implementations will be presented. Many existing ERP systems were surveyed and presented from ICT / software engineering point of view.

  3. The evaluation of the pyrochemistry for the treatment of Gen IV nuclear fuels Inert matrix chlorination studies in the gas phase or molten chloride salts

    Science.gov (United States)

    Bourg, S.; Péron, F.; Lacquement, J.

    2007-01-01

    The structure of the fuels for the future Gen IV nuclear reactors will be totally different from those of PWR, especially for the GFR concept including a closed cycle. In these reactors, fissile materials (carbides or nitrides of actinides) should be surrounded by an inert matrix. In order to build a reprocessing process scheme, the behavior of the potential inert matrices (silicon carbide, titanium nitride, and zirconium carbide and nitride) was studied by hydro- and pyrometallurgy. This paper deals with the chlorination results at high temperature by pyrometallurgy. For the first time, the reactivity of the matrix towards chlorine gas was assessed in the gas phase. TiN, ZrN and ZrC are very reactive from 400 °C whereas it is necessary to be over 900 °C for SiC to be as fast. In molten chloride melts, the bubbling of chlorine gas is less efficient than in gas phase but it is possible to attack the matrices. Electrochemical methods were also used to dissolve the refractory materials, leading to promising results with TiN, ZrN and ZrC. The massive SiC samples used were not conductive enough to be studied and in this case specific SiC-coated carbon electrodes were used. The key point of these studies was to find a method to separate the matrix compounds from the fissile material in order to link the head to the core of the process (electrochemical separation or liquid-liquid reductive extraction in the case of a pyrochemical reprocessing).

  4. New RELAP5-3D Lead and LBE Thermophysical Properties Implementation for Safety Analysis of Gen IV Reactors

    Directory of Open Access Journals (Sweden)

    P. Balestra

    2016-01-01

    Full Text Available The latest versions of RELAP5-3D© code allow the simulation of thermodynamic system, using different type of working fluids, that is, liquid metals, molten salt, diathermic oil, and so forth, thanks to the ATHENA code integration. The RELAP5-3D© water thermophysical properties are largely verified and validated; however there are not so many experiments to generate the liquid metals ones in particular for the Lead and the Lead Bismuth Eutectic. Recently, new and more accurate experimental data are available for liquid metals. The comparison between these state-of-the-art data and the RELAP5-3D© default thermophysical properties shows some discrepancy; therefore a tool for the generation of new properties binary files has been developed. All the available data came from experiments performed at atmospheric pressure. Therefore, to extend the pressure domain below and above this pressure, the tool fits a semiempirical model (soft sphere model with inverse-power-law potential, specific for the liquid metals. New binary files of thermophysical properties, with a detailed mesh grid of point to reduce the code mass error (especially for the Lead, were generated with this tool. Finally, calculations using a simple natural circulation loop were performed to understand the differences between the default and the new properties.

  5. Self-Organized Criticality Systems

    Science.gov (United States)

    Aschwanden, M. J.

    2013-07-01

    Contents: (1) Introduction - Norma B. Crosby --- (2) Theoretical Models of SOC Systems - Markus J. Aschwanden --- (3) SOC and Fractal Geometry - R. T. James McAteer --- (4) Percolation Models of Self-Organized Critical Phenomena - Alexander V. Milovanov --- (5) Criticality and Self-Organization in Branching Processes: Application to Natural Hazards - Álvaro Corral, Francesc Font-Clos --- (6) Power Laws of Recurrence Networks - Yong Zou, Jobst Heitzig, Jürgen Kurths --- (7) SOC computer simolations - Gunnar Pruessner --- (8) SOC Laboratory Experiments - Gunnar Pruessner --- (9) Self-Organizing Complex Earthquakes: Scaling in Data, Models, and Forecasting - Michael K. Sachs et al. --- (10) Wildfires and the Forest-Fire Model - Stefan Hergarten --- (11) SOC in Landslides - Stefan Hergarten --- (12) SOC and Solar Flares - Paul Charbonneau --- (13) SOC Systems in Astrophysics - Markus J. Aschwanden ---

  6. VENUS-F: A fast lead critical core for benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Kochetkov, A.; Wagemans, J.; Vittiglio, G. [SCK.CEN, Boeretang 200, 2400 Mol (Belgium)

    2011-07-01

    The zero-power thermal neutron water-moderated facility VENUS at SCK-CEN has been extensively used for benchmarking in the past. In accordance with GEN-IV design tasks (fast reactor systems and accelerator driven systems), the VENUS facility was modified in 2007-2010 into the fast neutron facility VENUS-F with solid core components. This paper introduces the projects GUINEVERE and FREYA, which are being conducted at the VENUS-F facility, and it presents the measurement results obtained at the first critical core. Throughout the projects other fast lead benchmarks also will be investigated. The measurement results of the different configurations can all be used as fast neutron benchmarks. (authors)

  7. 75 FR 5146 - Hewlett Packard Company Business Critical Systems, Mission Critical Business Software Division...

    Science.gov (United States)

    2010-02-01

    ... Employment and Training Administration Hewlett Packard Company Business Critical Systems, Mission Critical... Business Critical Systems, Mission Critical Business Software Division, OpenVMS Operating System... of Hewlett Packard Company, Business Critical Systems, Mission Critical Business Software Division...

  8. 75 FR 11918 - Hewlett Pachard Company, Business Critical Systems, Mission Critical Business Software Division...

    Science.gov (United States)

    2010-03-12

    ... Employment and Training Administration Hewlett Pachard Company, Business Critical Systems, Mission Critical... Company, Business Critical Systems, Mission Critical Business Software Division, Openvms Operating System..., applicable to workers of Hewlett Packard Company, Business Critical Systems, Mission Critical Business...

  9. Safety-critical Java for embedded systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Dalsgaard, Andreas Engelbredt; Hansen, René Rydhof

    2016-01-01

    This paper presents the motivation for and outcomes of an engineering research project on certifiable Javafor embedded systems. The project supports the upcoming standard for safety-critical Java, which defines asubset of Java and libraries aiming for development of high criticality systems...

  10. Safety-critical Java for embedded systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Dalsgaard, Andreas Engelbredt; Hansen, René Rydhof

    2016-01-01

    This paper presents the motivation for and outcomes of an engineering research project on certifiable Javafor embedded systems. The project supports the upcoming standard for safety-critical Java, which defines asubset of Java and libraries aiming for development of high criticality systems....... The outcome of this projectinclude prototype safety-critical Java implementations, a time-predictable Java processor, analysis tools formemory safety, and example applications to explore the usability of safety-critical Java for this applicationarea. The text summarizes developments and key contributions...

  11. Critical infrastructure systems of systems assessment methodology.

    Energy Technology Data Exchange (ETDEWEB)

    Sholander, Peter E.; Darby, John L.; Phelan, James M.; Smith, Bryan; Wyss, Gregory Dane; Walter, Andrew; Varnado, G. Bruce; Depoy, Jennifer Mae

    2006-10-01

    Assessing the risk of malevolent attacks against large-scale critical infrastructures requires modifications to existing methodologies that separately consider physical security and cyber security. This research has developed a risk assessment methodology that explicitly accounts for both physical and cyber security, while preserving the traditional security paradigm of detect, delay, and respond. This methodology also accounts for the condition that a facility may be able to recover from or mitigate the impact of a successful attack before serious consequences occur. The methodology uses evidence-based techniques (which are a generalization of probability theory) to evaluate the security posture of the cyber protection systems. Cyber threats are compared against cyber security posture using a category-based approach nested within a path-based analysis to determine the most vulnerable cyber attack path. The methodology summarizes the impact of a blended cyber/physical adversary attack in a conditional risk estimate where the consequence term is scaled by a ''willingness to pay'' avoidance approach.

  12. Critical infrastructure system security and resiliency

    CERN Document Server

    Biringer, Betty; Warren, Drake

    2013-01-01

    Security protections for critical infrastructure nodes are intended to minimize the risks resulting from an initiating event, whether it is an intentional malevolent act or a natural hazard. With an emphasis on protecting an infrastructure's ability to perform its mission or function, Critical Infrastructure System Security and Resiliency presents a practical methodology for developing an effective protection system that can either prevent undesired events or mitigate the consequences of such events.Developed at Sandia National Labs, the authors' analytical approach and

  13. Critical Points in Distance Learning System

    Directory of Open Access Journals (Sweden)

    Airina Savickaitė

    2013-08-01

    Full Text Available Purpose – This article presents the results of distance learning system analysis, i.e. the critical elements of the distance learning system. The critical points of distance learning are a part of distance education online environment interactivity/community process model. The most important is the fact that the critical point is associated with distance learning participants. Design/methodology/approach – Comparative review of articles and analysis of distance learning module. Findings – A modern man is a lifelong learner and distance learning is a way to be a modern person. The focus on a learner and feedback is the most important thing of learning distance system. Also, attention should be paid to the lecture-appropriate knowledge and ability to convey information. Distance system adaptation is the way to improve the learner’s learning outcomes. Research limitations/implications – Different learning disciplines and learning methods may have different critical points. Practical implications – The information of analysis could be important for both lecturers and students, who studies distance education systems. There are familiar critical points which may deteriorate the quality of learning. Originality/value – The study sought to develop remote systems for applications in order to improve the quality of knowledge. Keywords: distance learning, process model, critical points. Research type: review of literature and general overview.

  14. Critical care nursing: Embedded complex systems.

    Science.gov (United States)

    Trinier, Ruth; Liske, Lori; Nenadovic, Vera

    2016-01-01

    Variability in parameters such as heart rate, respiratory rate and blood pressure defines healthy physiology and the ability of the person to adequately respond to stressors. Critically ill patients have lost this variability and require highly specialized nursing care to support life and monitor changes in condition. The critical care environment is a dynamic system through which information flows. The critical care unit is typically designed as a tree structure with generally one attending physician and multiple nurses and allied health care professionals. Information flow through the system allows for identification of deteriorating patient status and timely interventionfor rescue from further deleterious effects. Nurses provide the majority of direct patient care in the critical care setting in 2:1, 1:1 or 1:2 nurse-to-patient ratios. The bedside nurse-critically ill patient relationship represents the primary, real-time feedback loop of information exchange, monitoring and treatment. Variables that enhance information flow through this loop and support timely nursing intervention can improve patient outcomes, while barriers can lead to errors and adverse events. Examining patient information flow in the critical care environment from a dynamic systems perspective provides insights into how nurses deliver effective patient care and prevent adverse events.

  15. Critical Point Theory for Lagrangian Systems

    CERN Document Server

    Mazzucchelli, Marco

    2012-01-01

    Lagrangian systems constitute a very important and old class in dynamics. Their origin dates back to the end of the eighteenth century, with Joseph-Louis Lagrange's reformulation of classical mechanics. The main feature of Lagrangian dynamics is its variational flavor: orbits are extremal points of an action functional. The development of critical point theory in the twentieth century provided a powerful machinery to investigate existence and multiplicity questions for orbits of Lagrangian systems. This monograph gives a modern account of the application of critical point theory, and more spec

  16. Security for safety critical space borne systems

    Science.gov (United States)

    Legrand, Sue

    1987-01-01

    The Space Station contains safety critical computer software components in systems that can affect life and vital property. These components require a multilevel secure system that provides dynamic access control of the data and processes involved. A study is under way to define requirements for a security model providing access control through level B3 of the Orange Book. The model will be prototyped at NASA-Johnson Space Center.

  17. Safety-Critical Java for Embedded Systems

    DEFF Research Database (Denmark)

    Rios Rivas, Juan Ricardo

    for Java aims at providing a reduced set of the Java programming language that can be used for systems that need to be certified at the highest levels of criticality. Safety-critical Java (SCJ) restricts how a developer can structure an application by providing a specific programming model...... and by restricting the set of methods and libraries that can be used. Furthermore, its memory model do not use a garbage-collected heap but scoped memories. In this thesis we examine the use of the SCJ specification through an implementation in a time-predictable, FPGA-based Java processor. The specification is now...

  18. Percolation systems away from the critical point

    Indian Academy of Sciences (India)

    Deepak Dhar

    2002-02-01

    This article reviews some effects of disorder in percolation systems away from the critical density c. For densities below c, the statistics of large clusters defines the animals problem. Its relation to the directed animals problem and the Lee–Yang edge singularity problem is described. Rare compact clusters give rise to Griffiths singularities in the free energy of diluted ferromagnets, and lead to a very slow relaxation of magnetization. In biased diffusion on percolation clusters, trapping in dead-end branches leads to asymptotic drift velocity becoming zero for strong bias, and very slow relaxation of velocity near the critical bias field.

  19. Critical Time Crystals in Dipolar Systems

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D.; Abanin, Dmitry A.

    2017-07-01

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017), 10.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

  20. Critical dwell time of switched linear systems

    Institute of Scientific and Technical Information of China (English)

    Lijun ZHANG; Chunwen LI

    2006-01-01

    In this paper, we consider the relation between the switching dwell time and the stabilization of switched linear control systems. First of all, a concept of critical dwell time is given for switched linear systems without control inputs, and the critical dwell time is taken as an arbitrary given positive constant for a switched linear control systems with controllable switching models. Secondly, when a switched linear system has many stabilizable switching models, the problem of stabilization of the overall system is considered. An on-line feedback control is designed such that the overall system is asymptotically stabilizable under switching laws which depend only on those of uncontrollable subsystems of the switching models. Finally, when a switched system is partially controllable (While some switching models are probably unstabilizable), an on-line feedback control and a cyclic switching strategy are designed such that the overall system is asymptotically stabilizable if all switching models of this uncontrollable subsystems are asymptotically stable. In addition,algorithms for designing switching laws and controls are presented.

  1. Preliminary Conceptual Design for Safety Parameter display System of PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Hyunju; Seong, Seunghwan; Kim, Wansu; Kim, Donghoon; Son, Kwangseop; Jang, Gwisook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    A PGSFR (prototype Gen-IV sodium-cooled fast reactor) is under development at KAERI. A safety parameter display system (SPDS) should be designed for licensing the PGSFR in order to cope with the TMI action plan requirements. Thus, a preliminary conceptual design for the SPDS of PGSFR including licensing requirements, intrinsic function, critical variables and alarm legs for the SPDS of the PGSFR is studied herein. At first, some documents issued by NRC related to install a SPDS include the following: - NUREG-0737, Clarification of TMI Action Plan Requirements - NUREG-0696, Functional Criteria for Emergency Response Facilities - NUREG-0835, Human Factors Acceptance Criteria for the Safety Parameter display System, Draft Report for Comment. The preliminary concept design for the SPDS of the PGSFR was studied. In designing of the PGSFR, the studied design concept will be refined and implemented through further studies to acquire the approval of a safety analysis report of the PGSFR.

  2. Robust Security System for Critical Computers

    Directory of Open Access Journals (Sweden)

    Preet Inder Singh

    2012-06-01

    Full Text Available Among the various means of available resource protection including biometrics, password based system is most simple, user friendly, cost effective and commonly used, but this system having high sensitivity with attacks. Most of the advanced methods for authentication based on password encrypt the contents of password before storing or transmitting in physical domain. But all conventional cryptographic based encryption methods are having its own limitations, generally either in terms of complexity, efficiency or in terms of security. In this paper a simple method is developed that provide more secure and efficient means of authentication, at the same time simple in design for critical systems. Apart from protection, a step toward perfect security has taken by adding the feature of intruder detection along with the protection system. This is possible by merging various security systems with each other i.e password based security with keystroke dynamic, thumb impression with retina scan associated with the users. This new method is centrally based on user behavior and users related security system, which provides the robust security to the critical systems with intruder detection facilities.

  3. Slow Relaxation in Anderson Critical Systems

    Science.gov (United States)

    Choi, Soonwon; Yao, Norman; Choi, Joonhee; Kucsko, Georg; Lukin, Mikhail

    2016-05-01

    We study the single particle dynamics in disordered systems with long range hopping, focusing on the critical cases, i.e., the hopping amplitude decays as 1 /rd in d-dimension. We show that with strong on-site potential disorder, the return probability of the particle decays as power-law in time. As on-site potential disorder decreases, the temporal profile smoothly changes from a simple power-law to the sum of multiple power-laws with exponents ranged from 0 to νmax. We analytically compute the decay exponents using a simple resonance counting argument, which quantitatively agrees with exact numerical results. Our result implies that the dynamics in Anderson Critical systems are dominated by resonances. Harvard-MIT CUA, Kwanjeong Educational Fellowship, AFOSR MURI, Samsung Scholarship.

  4. DEVELOPMENT OF RISK-BASED AND TECHNOLOGY-INDEPENDENT SAFETY CRITERIA FOR GENERATION IV SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    William E. Kastenberg; Edward Blandford; Lance Kim

    2009-03-31

    This project has developed quantitative safety goals for Generation IV (Gen IV) nuclear energy systems. These safety goals are risk based and technology independent. The foundations for a new approach to risk analysis has been developed, along with a new operational definition of risk. This project has furthered the current state-of-the-art by developing quantitative safety goals for both Gen IV reactors and for the overall Gen IV nuclear fuel cycle. The risk analysis approach developed will quantify performance measures, characterize uncertainty, and address a more comprehensive view of safety as it relates to the overall system. Appropriate safety criteria are necessary to manage risk in a prudent and cost-effective manner. This study is also important for government agencies responsible for managing, reviewing, and for approving advanced reactor systems because they are charged with assuring the health and safety of the public.

  5. Critical Success Factors for Risk Management Systems

    OpenAIRE

    Yaraghi, Niam

    2009-01-01

    Despite the existence of extensive literature regarding risk management, there still seems to be lack of knowledge in identification of Critical Success Factors (CSFs) in this area. In this research Grounded Theory is implemented to identify CSFs in Risk Management Systems (RMS). Factor analysis and one-sample t-test are then used to refine and rank the CSFs based on the results of a survey which has been performed among Risk Management practitioners in various types of Swedish corporations. ...

  6. Quantum critical points in quantum impurity systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jung [Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universitaet Augsburg (Germany); Bulla, Ralf [Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universitaet Augsburg (Germany)]. E-mail: bulla@cpfs.mpg.de

    2005-04-30

    The numerical renormalization group method is used to investigate zero-temperature phase transitions in quantum impurity systems, in particular in the soft-gap Anderson model, where an impurity couples to a non-trivial fermionic bath. In this case, zero-temperature phase transitions occur between two different phases whose fixed points can be built up of non-interacting single-particle states. However, the quantum critical point cannot be described by non-interacting fermionic or bosonic excitations.

  7. Quantum critical points in quantum impurity systems

    Science.gov (United States)

    Lee, Hyun Jung; Bulla, Ralf

    2005-04-01

    The numerical renormalization group method is used to investigate zero-temperature phase transitions in quantum impurity systems, in particular in the soft-gap Anderson model, where an impurity couples to a non-trivial fermionic bath. In this case, zero-temperature phase transitions occur between two different phases whose fixed points can be built up of non-interacting single-particle states. However, the quantum critical point cannot be described by non-interacting fermionic or bosonic excitations.

  8. Regulatory Safety Issues in the Structural Design Criteria of ASME Section III Subsection NH and for Very High Temperatures for VHTR & GEN IV

    Energy Technology Data Exchange (ETDEWEB)

    William J. O’Donnell; Donald S. Griffin

    2007-05-07

    The objective of this task is to identify issues relevant to ASME Section III, Subsection NH [1], and related Code Cases that must be resolved for licensing purposes for VHTGRs (Very High Temperature Gas Reactor concepts such as those of PBMR, Areva, and GA); and to identify the material models, design criteria, and analysis methods that need to be added to the ASME Code to cover the unresolved safety issues. Subsection NH was originally developed to provide structural design criteria and limits for elevated-temperature design of Liquid Metal Fast Breeder Reactor (LMFBR) systems and some gas-cooled systems. The U.S. Nuclear Regulatory Commission (NRC) and its Advisory Committee for Reactor Safeguards (ACRS) reviewed the design limits and procedures in the process of reviewing the Clinch River Breeder Reactor (CRBR) for a construction permit in the late 1970s and early 1980s, and identified issues that needed resolution. In the years since then, the NRC and various contractors have evaluated the applicability of the ASME Code and Code Cases to high-temperature reactor designs such as the VHTGRs, and identified issues that need to be resolved to provide a regulatory basis for licensing. This Report describes: (1) NRC and ACRS safety concerns raised during the licensing process of CRBR , (2) how some of these issues are addressed by the current Subsection NH of the ASME Code; and (3) the material models, design criteria, and analysis methods that need to be added to the ASME Code and Code Cases to cover unresolved regulatory issues for very high temperature service.

  9. 3rd International Workshop on Critical Systems Development with UML

    OpenAIRE

    Jan Jürjens; Fernandez, Eduardo B.; Robert France; Bernhard Rumpe

    2017-01-01

    Topics of the Workshop include: --- Applications of UML to real-time systems security-critical systems dependable / safety-critical systems performance-critical systems embedded systems hybrid systems reactive systems --- Extensions of UML (UML-RT, UMLsec, Automotive UML, Embedded UML, ...) and new developments (UML 2.0, MDA) --- Modeling, synthesis, model transformation, code generation, testing, validation, and verification of critical systems using UML --- Aspect-oriented or Component-base...

  10. 3rd International Workshop on Critical Systems Development with UML

    OpenAIRE

    Jan Jürjens; Eduardo B. Fernandez; Robert France; Bernhard Rumpe

    2016-01-01

    Topics of the Workshop include: --- Applications of UML to real-time systems security-critical systems dependable / safety-critical systems performance-critical systems embedded systems hybrid systems reactive systems --- Extensions of UML (UML-RT, UMLsec, Automotive UML, Embedded UML, ...) and new developments (UML 2.0, MDA) --- Modeling, synthesis, model transformation, code generation, testing, validation, and verification of critical systems using UML --- Aspect-oriented or Component-base...

  11. New Materials for NGNP/Gen IV

    Energy Technology Data Exchange (ETDEWEB)

    Robert W. Swindeman; Douglas L. Marriott

    2009-12-18

    The bounding conditions were briefly summarized for the Next Generation Nuclear Plant (NGNP) that is the leading candidate in the Department of Energy Generation IV reactor program. Metallic materials essential to the successful development and proof of concept for the NGNP were identified. The literature bearing on the materials technology for high-temperature gas-cooled reactors was reviewed with emphasis on the needs identified for the NGNP. Several materials were identified for a more thorough study of their databases and behavioral features relative to the requirements ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NH.

  12. Critical Time Crystals in Dipolar Systems.

    Science.gov (United States)

    Ho, Wen Wei; Choi, Soonwon; Lukin, Mikhail D; Abanin, Dmitry A

    2017-07-07

    We analyze the quantum dynamics of periodically driven, disordered systems in the presence of long-range interactions. Focusing on the stability of discrete time crystalline (DTC) order in such systems, we use a perturbative procedure to evaluate its lifetime. For 3D systems with dipolar interactions, we show that the corresponding decay is parametrically slow, implying that robust, long-lived DTC order can be obtained. We further predict a sharp crossover from the stable DTC regime into a regime where DTC order is lost, reminiscent of a phase transition. These results are in good agreement with the recent experiments utilizing a dense, dipolar spin ensemble in diamond [Nature (London) 543, 221 (2017)NATUAS0028-083610.1038/nature21426]. They demonstrate the existence of a novel, critical DTC regime that is stabilized not by many-body localization but rather by slow, critical dynamics. Our analysis shows that the DTC response can be used as a sensitive probe of nonequilibrium quantum matter.

  13. Critical stability of few-body systems

    CERN Document Server

    Karmanov, V A

    2013-01-01

    When a two-body system is bound by a zero-range interaction, the corresponding three-body system -- considered in a non-relativistic framework -- collapses, that is its binding energy is unbounded from below. In a paper by J.V. Lindesay and H.P. Noyes it was shown that the relativistic effects result in an effective repulsion in such a way that three-body binding energy remains also finite, thus preventing the three-body system from collapse. Later, this property was confirmed in other works based on different versions of relativistic approaches. However, the three-body system exists only for a limited range of two-body binding energy values. For stronger two-body interaction, the relativistic three-body system still collapses. A similar phenomenon was found in a two-body systems themselves: a two-fermion system with one-boson exchange interaction in a state with zero angular momentum J=0 exists if the coupling constant does not exceed some critical value but it also collapses for larger coupling constant. Fo...

  14. Interdependent complex systems and critical infrastructures

    Science.gov (United States)

    D'Souza, Raissa

    2013-03-01

    Collections of networks are at the core of modern society, spanning technological, biological and social systems. Understanding the network structure of individual systems has lead to tremendous advances in the past decade. Yet, in reality, none of these individual networks lives in isolation and the consequences of interdependence can be surprising. Here we present results from random graph models of interacting networks. First, from a structural perspective, we show that interactions between different types of networks can enhance or delay the onset of large scale connectivity. Second, we consider a dynamical process on coupled networks. We use the classic Bak-Tang-Wiesenfeld sandpile model as an abstraction for cascades of load shedding and show that their can exist optimal levels of interconnectivity between networks that provide stabilizing effects with respect to cascades. We will also discuss recent advances in understanding interdependent social and technological networks which rely on coupling game theory to statistical physics and spatial models of random graphs that attempt to capture interdependencies in critical infrastructure systems.

  15. Critical Multitype Branching Systems: Extinction Results

    CERN Document Server

    Kevei, Peter

    2011-01-01

    We consider a critical branching particle system in $\\R^d$, composed of individuals of a finite number of types $i\\in\\{1,...,K\\}$. Each individual of type $i$ moves independently according to a symmetric $\\alpha_i$-stable motion. We assume that the particle lifetimes and offspring distributions are type-dependent. Under the usual independence assumptions in branching systems, we prove extinction theorems in the following cases: (1) all the particle lifetimes have finite mean, or (2) there is a type whose lifetime distribution has heavy tail, and the other lifetimes have finite mean. We get a more complex dynamics by assuming in case (2) that the most mobile particle type corresponds to a finite-mean lifetime: in this case, local extinction of the population is determined by an interaction of the parameters (offspring variability, mobility, longevity) of the long-living type and those of the most mobile type. The proofs are based on a precise analysis of the occupation times of a related Markov renewal process...

  16. Why Mission-Critical Systems Are Critical to the Future of Academic Libraries

    Science.gov (United States)

    Oberlander, Cyril

    2012-01-01

    A mission-critical system is one that is so intertwined with the operation of an organization that the organization can scarcely function without it. Just as in corporations, mission-critical library systems offer the capability to unlock talent and time. They are essential to the transformation of higher education and the learning environment. A…

  17. The Criticality Hypothesis in Neural Systems

    Science.gov (United States)

    Karimipanah, Yahya

    There is mounting evidence that neural networks of the cerebral cortex exhibit scale invariant dynamics. At the larger scale, fMRI recordings have shown evidence for spatiotemporal long range correlations. On the other hand, at the smaller scales this scale invariance is marked by the power law distribution of the size and duration of spontaneous bursts of activity, which are referred as neuronal avalanches. The existence of such avalanches has been confirmed by several studies in vitro and in vivo, among different species and across multiple scales, from spatial scale of MEG and EEG down to single cell resolution. This prevalent scale free nature of cortical activity suggests the hypothesis that the cortex resides at a critical state between two phases of order (short-lasting activity) and disorder (long-lasting activity). In addition, it has been shown, both theoretically and experimentally, that being at criticality brings about certain functional advantages for information processing. However, despite the plenty of evidence and plausibility of the neural criticality hypothesis, still very little is known on how the brain may leverage such criticality to facilitate neural coding. Moreover, the emergent functions that may arise from critical dynamics is poorly understood. In the first part of this thesis, we review several pieces of evidence for the neural criticality hypothesis at different scales, as well as some of the most popular theories of self-organized criticality (SOC). Thereafter, we will focus on the most prominent evidence from small scales, namely neuronal avalanches. We will explore the effect of adaptation and how it can maintain scale free dynamics even at the presence of external stimuli. Using calcium imaging we also experimentally demonstrate the existence of scale free activity at the cellular resolution in vivo. Moreover, by exploring the subsampling issue in neural data, we will find some fundamental constraints of the conventional methods

  18. Critical behavior of non-ideal systems

    CERN Document Server

    Ivanov, Dmitry Yu

    2008-01-01

    Dmitry Yu. Ivanov is a professor at the Baltic State Technical University (St. Petersburg, Russia). His research focuses on thermodynamics, critical phenomena and phase transitions, theoretical and experimental investigations of multiple light scattering and correlation spectroscopy in application to Material Science and critical phenomena. His research activities included projects at the Nuclear Research Center in Dubna and Krichevsky Laboratory (Russia) and at the CNRS laboratories and Universities of Paris and Nice (France). He has authored about 70 scientific publications.

  19. Critical Casimir forces from the equation of state of quantum critical systems

    Science.gov (United States)

    Rançon, Adam; Henry, Louis-Paul; Rose, Félix; Cardozo, David Lopes; Dupuis, Nicolas; Holdsworth, Peter C. W.; Roscilde, Tommaso

    2016-10-01

    The mapping between a classical length and inverse temperature as imaginary time provides a direct equivalence between the Casimir force of a classical system in D dimensions and internal energy of a quantum system in d =D -1 dimensions. The scaling functions of the critical Casimir force of the classical system with periodic boundaries thus emerge from the analysis of the symmetry related quantum critical point. We show that both nonperturbative renormalization group and quantum Monte Carlo analysis of quantum critical points provide quantitative estimates for the critical Casimir force in the corresponding classical model, giving access to widely different aspect ratios for the geometry of confined systems. In light of these results, we propose protocols for the realization of critical Casimir forces for periodic boundaries through state-of-the-art cold-atom and solid-state experiments.

  20. A critical systems perspective on the design of organizational space

    NARCIS (Netherlands)

    Mobach, Mark P.

    2007-01-01

    This paper is the first to introduce critical systems thinking into a new emerging research strand: the design of organizational space. The study revealed two things. First, critical systems thinking provides a thorough framework to understand the possibilities to connect organization and building;

  1. Analysis of Criticality Accident Transients of Uranium Solution System

    Institute of Scientific and Technical Information of China (English)

    DUAN; Ming-hui; DU; Kai-wen; LIU; Zhen-hua

    2012-01-01

    <正>In the nuclear fuel cycle, fissile materials are often dissolved in water. Criticality accidents are likely to happen in the uranium solution system and release a large amount of energy and radioactive materials. Therefore, the criticality safety of uranium solution system is very important in the nuclear safety technology research.

  2. Existence of solutions for elliptic systems with critical Sobolev exponent

    Directory of Open Access Journals (Sweden)

    Pablo Amster

    2002-06-01

    Full Text Available We establish conditions for existence and for nonexistence of nontrivial solutions to an elliptic system of partial differential equations. This system is of gradient type and has a nonlinearity with critical growth.

  3. Validation of Flight Critical Control Systems

    Science.gov (United States)

    1991-12-01

    resonances , electromagnetic shielding/interference effects, power transients, cooling system performance, and other elements which are sensitive to the... Magnetic Capability *Electro Magnectic Itnterference -Lightning Protection - lectrical Girouinds - lectrica I Bondinog ( beiiical - Biological I -n vi...ments, the funtional specification, the design specification, the implementation and prototype, the pro- totye aircraft, and the production system

  4. Lie Symmetries and Criticality of Semilinear Differential Systems

    Directory of Open Access Journals (Sweden)

    Yuri Bozhkov

    2007-03-01

    Full Text Available We discuss the notion of criticality of semilinear differential equations and systems, its relations to scaling transformations and the Noether approach to Pokhozhaev's identities. For this purpose we propose a definition for criticality based on the S. Lie symmetry theory. We show that this definition is compatible with the well-known notion of critical exponent by considering various examples. We also review some related recent papers.

  5. A New Jacobian Matrix Method for Assessing Similarity between Critical Experiments and Real Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sunghwan; Kim, Sang Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    For a metal fueled Sodium-cooled Fast Reactor (SFR), innovative reactors such as Prototype Gen-IV Sodium cooled Fast Reactor (PGSFR), unfortunately, experiment data from an operating reactor are unavailable because there are few operating reactors in the world. Hence, a critical experiment is the only way to obtain meaningful experiment data for the target core. However, there is a considerable geometrical difference between the critical assembly for a critical experiment and the target core. The neutron characteristics of a system are influenced by the geometrical difference. A number of researches have been performed to confirm the similarity between a critical experiment and a real reactor using a conventional representativity factor. The conventional representativity factor defined as S{sup T}{sub E}US{sub R} √S{sup T}{sub E}US{sub E}, √S{sup T}{sub R}US{sub R} provides insight of similarity between two sensitivity vectors for cross sections, but it did not provide a quantitative value. Hence, up to now, the influence of geometrical difference to the reactivity is believed to be negligible. In this paper, a new Jacobian matrix method is proposed to provide a quantitative error for geometrical differences between two systems. In this method, reactivity of the critical assembly is decomposed into phenomenon-based reactivity and geometry-based reactivity. The reactivity is then transformed into a target core geometry using a Jacobian matrix. Then, non-linearity of two different systems can be derived by comparing the transformed reactivity with the original reactivity of the target core. The maximum error of the transformed reactivity can be used as an additional uncertainty of the geometrical difference.

  6. Triggers for the critical engagement with decision support systems

    NARCIS (Netherlands)

    Hartmann, Timo; Javernick-Will, A.; Chinowsky, P.

    2012-01-01

    In previous work, we showed that the critical engagement with a decision sup- port system during its implementation by a project team is an important an- tecedent for the successful later use of the technology. However, the mechanisms that trigger such critical engagement are so far not well

  7. Triggers for the critical engagement with decision support systems

    NARCIS (Netherlands)

    Hartmann, Timo; Javernick-Will, A.; Chinowsky, P.

    2012-01-01

    In previous work, we showed that the critical engagement with a decision sup- port system during its implementation by a project team is an important an- tecedent for the successful later use of the technology. However, the mechanisms that trigger such critical engagement are so far not well underst

  8. Systems approach critical to agroecosystems management

    Science.gov (United States)

    Sustainable dryland agriculture in the semi-arid Great Plains of the U.S. depends on achieving economic yields while maintaining soil resources. The traditional system of conventional tillage wheat-fallow was vulnerable to excessive soil erosion which resulted in excessive organic matter loss. No-...

  9. Management Systems Design: A Critical Appraisal

    Science.gov (United States)

    Schroeder, Roger G.

    1977-01-01

    Improved management systems can be developed for colleges and universities if assumptions are correct and a well-defined process is used. A life-cycle approach is suggested whose subsystems and implementation at Augsburg College, a small private liberal arts institution, are described. (LBH)

  10. Critical thinking and systems thinking: towards a critical literacy for systems thinking in practice

    OpenAIRE

    Reynolds, Martin

    2011-01-01

    About the book:\\ud In reflective problem solving and thoughtful decision making using critical thinking one considers evidence, the context of judgment, the relevant criteria for making the judgment well, the applicable methods or techniques for forming the judgment, and the applicable theoretical constructs for understanding the problem and the question at hand. In this book, the authors present topical research in the study of critical thinking. Topics discussed include developing critical ...

  11. On the constrained growth of complex critical systems

    CERN Document Server

    Hébert-Dufresne, Laurent; Dubé, Louis J

    2012-01-01

    Critical, or scale independent, systems are so ubiquitous, that gaining theoretical insights on their nature and properties has many direct repercussions in social and natural sciences. In this report, we start from the simplest possible growth model for critical systems and deduce constraints in their growth : the well-known preferential attachment principle, and, mainly, a new law of temporal scaling. We then support our scaling law with a number of calculations and simulations of more complex theoretical models : critical percolation, self-organized criticality and fractal growth. Perhaps more importantly, the scaling law is also observed in a number of empirical systems of quite different nature : prose samples, artistic and scientific productivity, citation networks, and the topology of the Internet. We believe that these observations pave the way towards a general and analytical framework for predicting the growth of complex systems.

  12. Systems thinking, critical realism and philosophy a confluence of ideas

    CERN Document Server

    Mingers, John

    2014-01-01

    Systems Thinking, Critical Realism and Philosophy: A Confluence of Ideas seeks to re-address the whole question of philosophy and systems thinking for the twenty first century and provide a new work that would be of value to both systems and philosophy. This is a highly opportune time when different fields - critical realism, philosophy of science and systems thinking - are all developing around the same set of concepts and yet not realizing it. This book will be of interest to the academic systems community worldwide and due to it's interdisciplinary coverage, it will also

  13. Surveying the critical success factors of BPM-systems implementation.

    NARCIS (Netherlands)

    Ravesteyn, P.; Batenburg, R.

    2010-01-01

    Purpose – The purpose of this paper is to explore if there is a common ground for the definition of business process management (BPM) and BPM-systems, as well as the critical success factors (CSFs) for BPM-system implementation. A BPM-system implementation framework is validated that classifies the

  14. Surveying the critical success factors of BPM-systems implementation.

    NARCIS (Netherlands)

    Ravesteyn, P.; Batenburg, R.

    2010-01-01

    Purpose – The purpose of this paper is to explore if there is a common ground for the definition of business process management (BPM) and BPM-systems, as well as the critical success factors (CSFs) for BPM-system implementation. A BPM-system implementation framework is validated that classifies the

  15. Formal methods for industrial critical systems a survey of applications

    CERN Document Server

    Margaria-Steffen, Tiziana

    2012-01-01

    "Today, formal methods are widely recognized as an essential step in the design process of industrial safety-critical systems. In its more general definition, the term formal methods encompasses all notations having a precise mathematical semantics, together with their associated analysis methods, that allow description and reasoning about the behavior of a system in a formal manner.Growing out of more than a decade of award-winning collaborative work within the European Research Consortium for Informatics and Mathematics, Formal Methods for Industrial Critical Systems: A Survey of Applications presents a number of mainstream formal methods currently used for designing industrial critical systems, with a focus on model checking. The purpose of the book is threefold: to reduce the effort required to learn formal methods, which has been a major drawback for their industrial dissemination; to help designers to adopt the formal methods which are most appropriate for their systems; and to offer a panel of state-of...

  16. Assessing Reliability: Critical Corrections for a Critical Examination of the Rorschach Comprehensive System.

    Science.gov (United States)

    Meyer, Gregory J.

    1997-01-01

    In reply to criticism of the Rorschach Comprehensive System (CS) by J. Wood, M. Nezworski, and W. Stejskal (1996), this article presents a meta-analysis of published data indicating that the CS has excellent chance-corrected interrater reliability. It is noted that the erroneous assumptions of Wood et al. make their assertions about validity…

  17. Network Randomization and Dynamic Defense for Critical Infrastructure Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Adrian R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Mitchell Tyler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hamlet, Jason [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stout, William M.S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lee, Erik [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    Critical Infrastructure control systems continue to foster predictable communication paths, static configurations, and unpatched systems that allow easy access to our nation's most critical assets. This makes them attractive targets for cyber intrusion. We seek to address these attack vectors by automatically randomizing network settings, randomizing applications on the end devices themselves, and dynamically defending these systems against active attacks. Applying these protective measures will convert control systems into moving targets that proactively defend themselves against attack. Sandia National Laboratories has led this effort by gathering operational and technical requirements from Tennessee Valley Authority (TVA) and performing research and development to create a proof-of-concept solution. Our proof-of-concept has been tested in a laboratory environment with over 300 nodes. The vision of this project is to enhance control system security by converting existing control systems into moving targets and building these security measures into future systems while meeting the unique constraints that control systems face.

  18. X(5) Critical-Point Structure in a Finite System

    CERN Document Server

    Leviatan, A

    2005-01-01

    X(5) is a paradigm for the structure at the critical point of a particular first-order phase transition for which the intrinsic energy surface has two degenerate minima separated by a low barrier. For a finite system, we show that the dynamics at such a critical point can be described by an effective deformation determined by minimizing the energy surface after projection onto angular momentum zero, and combined with two-level mixing. Wave functions of a particular analytic form are used to derive estimates for energies and quadrupole rates at the critical point.

  19. Critical-point symmetry in a finite system.

    Science.gov (United States)

    Leviatan, A; Ginocchio, J N

    2003-05-30

    At a critical point of a second-order phase transition the intrinsic energy surface is flat and there is no stable minimum value of the deformation. However, for a finite system, we show that there is an effective deformation which can describe the dynamics at the critical point. This effective deformation is determined by minimizing the energy surface after projection onto the appropriate symmetries. We derive analytic expressions for energies and quadrupole rates which provide good estimates for these observables at the critical point.

  20. Critical-Point Symmetry in a Finite System

    CERN Document Server

    Leviatan, A

    2003-01-01

    At a critical point of a second order phase transition the intrinsic energy surface is flat and there is no stable minimum value of the deformation. However, for a finite system, we show that there is an effective deformation which can describe the dynamics at the critical point. This effective deformation is determined by minimizing the energy surface after projection onto the appropriate symmetries. We derive analytic expressions for energies and quadrupole rates which provide good estimates for these observables at the critical point.

  1. Intelligent monitoring, control, and security of critical infrastructure systems

    CERN Document Server

    Polycarpou, Marios

    2015-01-01

    This book describes the challenges that critical infrastructure systems face, and presents state of the art solutions to address them. How can we design intelligent systems or intelligent agents that can make appropriate real-time decisions in the management of such large-scale, complex systems? What are the primary challenges for critical infrastructure systems? The book also provides readers with the relevant information to recognize how important infrastructures are, and their role in connection with a society’s economy, security and prosperity. It goes on to describe state-of-the-art solutions to address these points, including new methodologies and instrumentation tools (e.g. embedded software and intelligent algorithms) for transforming and optimizing target infrastructures. The book is the most comprehensive resource to date for professionals in both the private and public sectors, while also offering an essential guide for students and researchers in the areas of modeling and analysis of critical in...

  2. On Critical Behaviour in Systems of Hamiltonian Partial Differential Equations

    Science.gov (United States)

    Dubrovin, Boris; Grava, Tamara; Klein, Christian; Moro, Antonio

    2015-06-01

    We study the critical behaviour of solutions to weakly dispersive Hamiltonian systems considered as perturbations of elliptic and hyperbolic systems of hydrodynamic type with two components. We argue that near the critical point of gradient catastrophe of the dispersionless system, the solutions to a suitable initial value problem for the perturbed equations are approximately described by particular solutions to the Painlevé-I (P) equation or its fourth-order analogue P. As concrete examples, we discuss nonlinear Schrödinger equations in the semiclassical limit. A numerical study of these cases provides strong evidence in support of the conjecture.

  3. Critical experiments analysis by ABBN-90 constant system

    Energy Technology Data Exchange (ETDEWEB)

    Tsiboulia, A.; Nikolaev, M.N.; Golubev, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)] [and others

    1997-06-01

    The ABBN-90 is a new version of the well-known Russian group-constant system ABBN. Included constants were calculated based on files of evaluated nuclear data from the BROND-2, ENDF/B-VI, and JENDL-3 libraries. The ABBN-90 is intended for the calculation of different types of nuclear reactors and radiation shielding. Calculations of criticality safety and reactivity accidents are also provided by using this constant set. Validation of the ABBN-90 set was made by using a computerized bank of evaluated critical experiments. This bank includes the results of experiments conducted in Russia and abroad of compact spherical assemblies with different reflectors, fast critical assemblies, and fuel/water-solution criticalities. This report presents the results of the calculational analysis of the whole collection of critical experiments. All calculations were produced with the ABBN-90 group-constant system. Revealed discrepancies between experimental and calculational results and their possible reasons are discussed. The codes and archives INDECS system is also described. This system includes three computerized banks: LEMEX, which consists of evaluated experiments and their calculational results; LSENS, which consists of sensitivity coefficients; and LUND, which consists of group-constant covariance matrices. The INDECS system permits us to estimate the accuracy of neutronics calculations. A discussion of the reliability of such estimations is finally presented. 16 figs.

  4. Critical quasienergy states in driven many-body systems

    Science.gov (United States)

    Bastidas Valencia, Victor Manuel; Engelhardt, Georg; Perez-Fernandez, Pedro; Vogl, Malte; Brandes, Tobias

    2015-03-01

    A quantum phase transition (QPT) is characterized by non-analyticities of ground-state properties at the critical points. Recently it has been shown that quantum criticality emerges also in excited states of the system, which is referred to as an excited-state quantum phase transition (ESQPT). This kind of quantum criticality is intimately related to a level clustering at critical energies, which results in a logarithmic singularity in the density of states. Most of the previous studies on quantum criticality in excited states have been focused on time independent systems. Here we study spectral singularities that appear in periodically-driven many-body systems and show how the external control allows one to engineer geometrical features of the quasienergy landscape. In particular, we study singularities in the quasienergy spectrum of a fully-connected network consisting of two-level systems with time-dependent interactions. We discuss the characteristic signatures of these singularities in observables like the magnetization, which should be measurable with current technology. The authors gratefully acknowledge financial support by the DFG via grants BRA 1528/7, BRA 1528/8, SFB 910 (V.M.B., T.B.), the Spanish Ministerio de Ciencia e Innovacion (Grants No. FIS2011-28738-C02-01) and Junta de Andalucia (Grants No. FQM160).

  5. Validation of criticality calculation for systems with MOX powders

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, Tatiana; Rouyer, Veronique [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France); Rozhikhin, Yevgeniy; Tsiboulia, Anatoly [Institute for Physics and Power Engineering, Obninsk (Russian Federation)

    2008-07-01

    In 2005-2006, a series of experiments referred to as BFS/MOX was conducted at the BFS-1 experimental facility in IPPE, Russia. The program was designed to provide a basis for validation of criticality calculations for MOX fuel manufacturing processes and particularly with low-moderated MOX fissile media. The extensive experimental program was performed on those configurations, including criticality and reactor-type parameters measurements. The experiments were evaluated, peer reviewed, and analyzed with various codes and cross-section data. Criticality validation study was performed employing sensitivity/uncertainty technique based on the generalized linear least square method. The paper illustrates different tools' performance when calculating criticality for the BFS/MOX configurations and focused upon the validation process and results for generic application systems with weapons-grade plutonium. (authors)

  6. Formal methods in the development of safety critical software systems

    Energy Technology Data Exchange (ETDEWEB)

    Williams, L.G. [Software Engineering Research, Boulder, CO (United States)

    1991-11-15

    As the use of computers in critical control systems such as aircraft controls, medical instruments, defense systems, missile controls, and nuclear power plants has increased, concern for the safety of those systems has also grown. Much of this concern has focused on the software component of those computer-based systems. This is primarily due to historical experience with software systems that often exhibit larger numbers of errors than their hardware counterparts and the fact that the consequences of a software error may endanger human life, property, or the environment. A number of different techniques have been used to address the issue of software safety. Some are standard software engineering techniques aimed at reducing the number of faults in a software protect, such as reviews and walkthroughs. Others, including fault tree analysis, are based on identifying and reducing hazards. This report examines the role of one such technique, formal methods, in the development of software for safety critical systems. The use of formal methods to increase the safety of software systems is based on their role in reducing the possibility of software errors that could lead to hazards. The use of formal methods in the development of software systems is controversial. Proponents claim that the use of formal methods can eliminate errors from the software development process, and produce programs that are probably correct. Opponents claim that they are difficult to learn and that their use increases development costs unacceptably. This report discusses the potential of formal methods for reducing failures in safety critical software systems.

  7. Critical Review On Management Information System And Accounting Information System

    Directory of Open Access Journals (Sweden)

    Galuh Tresna Murti

    2015-08-01

    Full Text Available This paper is aimed at investigating the correlation between management information system and accounting information system to gain better understanding of each system.After conducting reviews on available literatures it is concluded in this article that arguments among experts still clearly prevail about both system. Different arguments are not to be eliminated as each argument is supported by adequate literatures and difference in system is a common thing due to differences in experiences point of views and interests of the experts.This paper argues that since management information system is available in every part of an organization therefore accounting information system is the sub-system of management information system which main objective is to use organization information system effectively.

  8. The commons from a critical social systems perspective

    Directory of Open Access Journals (Sweden)

    Wolfgang Hofkirchner

    2014-04-01

    Full Text Available Normal 0 21 false false false IT JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-ansi-language:DE; mso-fareast-language:EN-US;} When developing the so-called Salzburg Approach to Information and Communication Technologies (ICTs and Society in the years 2004 to 2010, the sociology of technology the then working group of mine at the University of Salzburg used was based upon a combination of critical thinking and systems thinking – of Critical Theory and Systems Theory. Criticism and systemism both include what I’m used to calling the Logic of the Third. The Logic of the Third is the foundation of a critical social systems theory.  

  9. Criticality in conserved dynamical systems: Experimental observation vs. exact properties

    Science.gov (United States)

    Marković, Dimitrije; Gros, Claudius; Schuelein, André

    2013-03-01

    Conserved dynamical systems are generally considered to be critical. We study a class of critical routing models, equivalent to random maps, which can be solved rigorously in the thermodynamic limit. The information flow is conserved for these routing models and governed by cyclic attractors. We consider two classes of information flow, Markovian routing without memory and vertex routing involving a one-step routing memory. Investigating the respective cycle length distributions for complete graphs, we find log corrections to power-law scaling for the mean cycle length, as a function of the number of vertices, and a sub-polynomial growth for the overall number of cycles. When observing experimentally a real-world dynamical system one normally samples stochastically its phase space. The number and the length of the attractors are then weighted by the size of their respective basins of attraction. This situation is equivalent, for theory studies, to "on the fly" generation of the dynamical transition probabilities. For the case of vertex routing models, we find in this case power law scaling for the weighted average length of attractors, for both conserved routing models. These results show that the critical dynamical systems are generically not scale-invariant but may show power-law scaling when sampled stochastically. It is hence important to distinguish between intrinsic properties of a critical dynamical system and its behavior that one would observe when randomly probing its phase space.

  10. Clinical monitoring of systemic hemodynamics in critically ill newborns.

    NARCIS (Netherlands)

    Boode, W.P. de

    2010-01-01

    Circulatory failure is a major cause of mortality and morbidity in critically ill newborn infants. Since objective measurement of systemic blood flow remains very challenging, neonatal hemodynamics is usually assessed by the interpretation of various clinical and biochemical parameters. An overview

  11. Coagulation and complement system in critically ill patients.

    Science.gov (United States)

    Helling, H; Stephan, B; Pindur, G

    2015-01-01

    Activation of coagulation and inflammatory response including the complement system play a major role in the pathogenesis of critical illness. However, only limited data are available addressing the relationship of both pathways and its assessment of a predictive value for the clinical outcome in intense care medicine. Therefore, parameters of the coagulation and complement system were studied in patients with septicaemia and multiple trauma regarded as being exemplary for critical illness. 34 patients (mean age: 51.38 years (±16.57), 15 females, 19 males) were investigated at day 1 of admittance to the intensive care unit (ICU). Leukocytes, complement factors C3a and C5a were significantly (p complement system as part of the inflammatory response is a significant mechanism in septicaemia, whereas loss and consumption of blood components including parts of the coagulation and complement system is more characteristic for multiple trauma. Protein C in case of severe reduction might be of special concern for surviving in sepsis. Activation of haemostasis was occurring in both diseases, however, overt DIC was not confirmed in this study to be a leading mechanism in critically ill patients. MOF score, lactate, C1-inhibitor and prothrombin time have been the only statistically significant predictors for lethal outcome suggesting that organ function, microcirculation, haemostasis and inflammatory response are essential elements of the pathomechanism and clinical course of diseases among critically ill patients.

  12. Electronics system design techniques for safety critical applications

    CERN Document Server

    Sterpone, Luca

    2008-01-01

    Addresses the development of techniques for the evaluation and the hardening of designs implemented on SRAM-based Field Programmable Gate Arrays. This title presents a design methodology solving industrial designer''s needs for implementing electronic systems using SRAM-based FPGAs in critical environments, like the space or avionic ones.

  13. Disease scoring systems for oral lichen planus; a critical appraisal

    NARCIS (Netherlands)

    Wang, J.; van der Waal, I.

    2015-01-01

    The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus (OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity

  14. Disease scoring systems for oral lichen planus; a critical appraisal

    NARCIS (Netherlands)

    Wang, J.; van der Waal, I.

    2015-01-01

    The aim of the present study has been to critically review 22 disease scoring systems (DSSs) on oral lichen planus (OLP) that have been reported in the literature during the past decades. Although the presently available DSSs may all have some merit, particularly for research purposes, the diversity

  15. Criticality in conserved dynamical systems: experimental observation vs. exact properties.

    Science.gov (United States)

    Marković, Dimitrije; Gros, Claudius; Schuelein, André

    2013-03-01

    Conserved dynamical systems are generally considered to be critical. We study a class of critical routing models, equivalent to random maps, which can be solved rigorously in the thermodynamic limit. The information flow is conserved for these routing models and governed by cyclic attractors. We consider two classes of information flow, Markovian routing without memory and vertex routing involving a one-step routing memory. Investigating the respective cycle length distributions for complete graphs, we find log corrections to power-law scaling for the mean cycle length, as a function of the number of vertices, and a sub-polynomial growth for the overall number of cycles. When observing experimentally a real-world dynamical system one normally samples stochastically its phase space. The number and the length of the attractors are then weighted by the size of their respective basins of attraction. This situation is equivalent, for theory studies, to "on the fly" generation of the dynamical transition probabilities. For the case of vertex routing models, we find in this case power law scaling for the weighted average length of attractors, for both conserved routing models. These results show that the critical dynamical systems are generically not scale-invariant but may show power-law scaling when sampled stochastically. It is hence important to distinguish between intrinsic properties of a critical dynamical system and its behavior that one would observe when randomly probing its phase space.

  16. Integration of criticality alarm system at a fuel manufacturing facility

    Energy Technology Data Exchange (ETDEWEB)

    Longinov, M.; Pant, A. [Zircatec Precision Industries, Port Hope, Ontario (Canada)

    2005-07-01

    In response to the Power Uprate program at Bruce Power, Zircatec has committed to introduce, by Spring 2006 a new manufacturing line for the production of 43 element CANFLEX bundles containing Slightly Enriched Uranium (SEU) with a centre pin of blended dysprosia/urania (BDU). This is a new fuel design and is the first change in fuel design since the introduction of the current 37 element fuel over 20 years ago. As the primary fuel supplier to the reactor site that has chosen to utilize this new fuel design, Zircatec has agreed to manufacture and supply this new fuel at their facility in Port Hope, Ontario. Under this agreement, Zircatec is challenged with converting a fuel manufacturing facility to include the processing of enriched uranium. The challenge is to introduce the new concept of criticality control to a facility that traditionally does not have to deal with such a concept. One of the elements of the implementation is the criticality detection and alarm system - CIDAS. Since a criticality could go undetected by human senses, one of the methods of ensuring safety from radiation exposure in the event of a criticality is the installation of a criticality incident detection and alarm system. This early warning device could be the difference between low dose exposure and lethal exposure. This paper describes the challenges that Zircatec has faced with the installation of a criticality incident detection and alarm system. These challenges include determining the needs and requirements, determining appropriate specifications, selecting the right equipment, installing the equipment and training personnel in the operation of the new equipment. (author)

  17. Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    LeMone, D. V.

    2002-02-25

    Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours.

  18. Percolation and Critical Phenomena of AN Attractive Micellar System

    Science.gov (United States)

    Mallamace, F.; Chen, S. H.; Gambadauro, P.; Lombardo, D.; Faraone, A.; Tartaglia, P.

    In this work we study an attractive micellar system for which the percolation curve terminates near the critical point. We have studied such an intriguing situation by means of scattering (elastic and dynamical) and viscoelasticity experiments. Obtained data are accounted by considering in a proper way the fractal clustering processes typical of percolating systems and the related scaling concepts. We observe that the main role in the system structure and dynamics it is played by the cluster's partial screening of hydrodynamic interaction. This behaves on approaching the percolation threshold dramatic effects on the system rheological properties and on the density decay relaxations. The measured correlation functions assume a stretched exponential form and the system becomes strongly viscoelastic. The overall behavior of the measured dynamical and structural parameters indicates, that in the present micellar system, the clustering process originates dilute, poly-disperse and swelling structures. Finally, this originates an interesting situation observed in the present experiment. As it has been previously, proposed by A. Coniglio et al., percolation clusters can be considered to be "Ising clusters" with the same properties as the Fisher's critical droplets. Therefore at the critical point the percolation connectedness length (ξp) can be assumed as the diverging correlation length (ξp ≡ ξ) and the mean cluster size diverges as the susceptibility.

  19. Educationally Critical Aspects of the Concept of an Information System

    Directory of Open Access Journals (Sweden)

    Chris Cope

    2002-01-01

    Full Text Available An empirical study is reported which identified and compared a deep understanding of the concept of an information system (IS with the various levels of understanding of a group of undergraduate IS students. The aim was to identify the educationally critical aspects of the deep understanding. The study was significant in that the educationally critical aspects are not known, yet have significant implications for IS education and practice. Without addressing the critical aspects in teaching and learning about IS the development of an appropriate deep understanding by students is unlikely. The production of entry-level IS practitioners without a deep understanding of the concept of an IS is logically likely to have adverse implications for IS development projects.

  20. Identification of Critical Points in the Quality Management System

    Directory of Open Access Journals (Sweden)

    Tünde SZABÓ

    2011-10-01

    Full Text Available Creating a quality management system can help organizations and other stakeholders in satisfying customer needs and expectations. Moreover, a well-implemented quality management ensures the organization a capable structure to make continuous improvement actions. Thus, after the evaluation of the quality management system elements, the identification of critical points is a very important element. There are several ways of assessing and identifying these critical points; in this case, identification will be done by questionnaire survey carried out at the Székely National Museum in Saint George. The questionnaire aimed to assess the whole system of management and staff attitudes towards some considerations established by international standard ISO 9001:2008.

  1. Neural Network Based Intrusion Detection System for Critical Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Ondrej Linda; Milos Manic

    2009-07-01

    Resiliency and security in control systems such as SCADA and Nuclear plant’s in today’s world of hackers and malware are a relevant concern. Computer systems used within critical infrastructures to control physical functions are not immune to the threat of cyber attacks and may be potentially vulnerable. Tailoring an intrusion detection system to the specifics of critical infrastructures can significantly improve the security of such systems. The IDS-NNM – Intrusion Detection System using Neural Network based Modeling, is presented in this paper. The main contributions of this work are: 1) the use and analyses of real network data (data recorded from an existing critical infrastructure); 2) the development of a specific window based feature extraction technique; 3) the construction of training dataset using randomly generated intrusion vectors; 4) the use of a combination of two neural network learning algorithms – the Error-Back Propagation and Levenberg-Marquardt, for normal behavior modeling. The presented algorithm was evaluated on previously unseen network data. The IDS-NNM algorithm proved to be capable of capturing all intrusion attempts presented in the network communication while not generating any false alerts.

  2. Neural Network Based Intrusion Detection System for Critical Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Todd Vollmer; Ondrej Linda; Milos Manic

    2009-07-01

    Resiliency and security in control systems such as SCADA and Nuclear plant’s in today’s world of hackers and malware are a relevant concern. Computer systems used within critical infrastructures to control physical functions are not immune to the threat of cyber attacks and may be potentially vulnerable. Tailoring an intrusion detection system to the specifics of critical infrastructures can significantly improve the security of such systems. The IDS-NNM – Intrusion Detection System using Neural Network based Modeling, is presented in this paper. The main contributions of this work are: 1) the use and analyses of real network data (data recorded from an existing critical infrastructure); 2) the development of a specific window based feature extraction technique; 3) the construction of training dataset using randomly generated intrusion vectors; 4) the use of a combination of two neural network learning algorithms – the Error-Back Propagation and Levenberg-Marquardt, for normal behavior modeling. The presented algorithm was evaluated on previously unseen network data. The IDS-NNM algorithm proved to be capable of capturing all intrusion attempts presented in the network communication while not generating any false alerts.

  3. Complex Critical Exponents in Diluted Systems of Quantum Rotors

    Science.gov (United States)

    Fernandes, Rafael; Schmalian, Jörg

    2011-03-01

    In this work, we investigate the effects of the Berry phase 2 πρ on the critical properties of XY quantum-rotors that undergo a percolation transition. This model describes a variety of randomly-diluted quantum systems, such as interacting bosons coupled to a particle reservoir, quantum planar antiferromagnets under a perpendicular magnetic field, and Josephson-junction arrays with an external bias-voltage. Focusing on the quantum critical point at the percolation threshold, we find that, for rational ρ , one recovers the power-law behavior with the same critical exponents as in the case with no Berry phase. However, for irrational ρ , the low-energy excitations change completely and are given by emergent spinless fermions with fractal spectrum. As a result, critical properties that cannot be described by the usual Ginzburg-Landau-Wilson theory of phase transitions emerge, such as complex critical exponents, log-periodic oscillations, and dynamically-broken scale invariance. Research supported by the U.S. DOE, Office of BES, Materials Science and Engineering Division.

  4. Critical configurations for a system of semidegenerate fermions

    Science.gov (United States)

    Argüelles, Carlos R.; Ruffini, Remo; Fraga, Bernardo M. O.

    2014-09-01

    We study an isothermal system of semidegenerate self-gravitating fermions in general relativity. Such systems present mass density solutions with a central degenerate core, a plateau and a tail, this last following a power law behavior r -2. The different solutions are governed by the free parameters of the model: the degeneracy and the temperature parameters at the center and the particle mass m. We then analyze in detail the free parameter space for a fixed m in the keV region, by studying the one-parameter sequences of equilibrium configurations up to the critical point, which is represented by the maximum in a central density ( ρ 0) vs. core mass ( M c ) diagram. We show that for fully degenerate cores, the known expression for the critical core mass M {/c cr } ∝ m {/pl 3}/ m 2 is obtained, while for low degenerate cores, the critical core mass increases, showing temperature effects in a nonlinear way. The main result of this work is that when applying this theory to model the distribution of dark matter in galaxies from the very center to the outer halos, we do not find any critical corehalo configuration of self-gravitating fermions that would be able to explain the super-massive dark object in their centers and the outer halo simultaneously.

  5. Critical configurations for a system of semi degenerate fermions

    Energy Technology Data Exchange (ETDEWEB)

    Arguelles, Carlos R.; Ruffini, Remo [ICRANet, Piazzale della Repubblica, Pescara (Italy); Sapienza University of Rome, Rome (Italy); Fraga, Bernardo M. [Sapienza University of Rome, Rome (Italy); Universite de Nice Sophia Antipolis, CEDEX (France)

    2014-09-15

    We study an isothermal system of semi degenerate self-gravitating fermions in general relativity. Such systems present mass density solutions with a central degenerate core, a plateau and a tail, this last following a power law behavior r{sup -2}. The different solutions are governed by the free parameters of the model: the degeneracy and the temperature parameters at the center and the particle mass m. We then analyze in detail the free parameter space for a fixed m in the keV region, by studying the one-parameter sequences of equilibrium configurations up to the critical point, which is represented by the maximum in a central density (ρ{sub 0}) vs. core mass (M{sub c}) diagram. We show that for fully degenerate cores, the known expression for the critical core mass M{sup cr}{sub c} {sup a}pprox{sup m3}{sub pl}/m{sup 2} is obtained, while for low degenerate cores, the critical core mass increases, showing temperature effects in a nonlinear way. The main result of this work is that when applying this theory to model the distribution of dark matter in galaxies from the very center to the outer halos, we do not find any critical corehalo configuration of self-gravitating fermions that would be able to explain the super-massive dark object in their centers and the outer halo simultaneously.

  6. Description of Fracture Systems for External Criticality Reports

    Energy Technology Data Exchange (ETDEWEB)

    Jean-Philippe Nicot

    2001-09-21

    The purpose of this Analysis/Model Report (AMR) is to describe probabilistically the main features of the geometry of the fracture system in the vicinity of the repository. They will be used to determine the quantity of fissile material that could accumulate in the fractured rock underneath a waste package as it degrades. This AMR is to feed the geochemical calculations for external criticality reports. This AMR is done in accordance with the technical work plan (BSC (Bechtel SAIC Company) 2001 b). The scope of this AMR is restricted to the relevant parameters of the fracture system. The main parameters of interest are fracture aperture and fracture spacing distribution parameters. The relative orientation of the different fracture sets is also important because of its impact on criticality, but they will be set deterministically. The maximum accumulation of material depends primarily on the fracture porosity, combination of the fracture aperture, and fracture intensity. However, the fracture porosity itself is not sufficient to characterize the potential for accumulation of a fracture system. The fracture aperture is also important because it controls both the flow through the fracture and the potential plugging of the system. Other features contributing to the void space such as lithophysae are also investigated. On the other hand, no analysis of the matrix porosity is done. The parameters will be used in sensitivity analyses of geochemical calculations providing actinide accumulations and in the subsequent Monte Carlo criticality analyses.

  7. Medical education in cyberspace: critical considerations in the health system.

    Science.gov (United States)

    Yazdani, Shahram; Khoshgoftar, Zohreh; Ahmady, Soleiman; Rastegarpour, Hassan; Foroutan, Seyed Abbas

    2017-01-01

    Over the past few decades, two revolutionary approaches have emerged as a new form of medical education: Electronic Medical Education and Web-based Medical Education. A number of well-known medical institutions, such as Harvard and Johns Hopkins used a wide range of cyberspace capabilities to increase their competitiveness. Researchers have expressed that cyberspace will change health system's main objective of training physicians and medical education. We conducted this study to identify the health system critical considerations on core issues, involving the development of medical education on cyberspace. In order to conduct this study, we observed the steps of a critical literature review, combined with the 'Four-phase method' adopted by Carnwell and Daly. We focused on particular literature on health and cyber system functions; it was associated with systemic approach. We developed a six-level taxonomy, Cyber level, Governance level, Ministerial level, Organizational level, Program level and Performance level, as a key solution that can be applied for the success of medical education on cyberspace. The results were summarized and appraised in more details. Medical education on cyberspace is a complex interdisciplinary system. It is important that all aspects of the health systems be involved as integral to the development of cyber based medical education; without this convergence, we will be confused by the decisions made by others within the system. Health system should also communicate with those external sectors that are critical to achieving better learning on cyberspace. Integrated planning, governance and management of medical education in cyberspace are pivotal elements for the promotion.

  8. Architecture Level Safety Analyses for Safety-Critical Systems

    Directory of Open Access Journals (Sweden)

    K. S. Kushal

    2017-01-01

    Full Text Available The dependency of complex embedded Safety-Critical Systems across Avionics and Aerospace domains on their underlying software and hardware components has gradually increased with progression in time. Such application domain systems are developed based on a complex integrated architecture, which is modular in nature. Engineering practices assured with system safety standards to manage the failure, faulty, and unsafe operational conditions are very much necessary. System safety analyses involve the analysis of complex software architecture of the system, a major aspect in leading to fatal consequences in the behaviour of Safety-Critical Systems, and provide high reliability and dependability factors during their development. In this paper, we propose an architecture fault modeling and the safety analyses approach that will aid in identifying and eliminating the design flaws. The formal foundations of SAE Architecture Analysis & Design Language (AADL augmented with the Error Model Annex (EMV are discussed. The fault propagation, failure behaviour, and the composite behaviour of the design flaws/failures are considered for architecture safety analysis. The illustration of the proposed approach is validated by implementing the Speed Control Unit of Power-Boat Autopilot (PBA system. The Error Model Annex (EMV is guided with the pattern of consideration and inclusion of probable failure scenarios and propagation of fault conditions in the Speed Control Unit of Power-Boat Autopilot (PBA. This helps in validating the system architecture with the detection of the error event in the model and its impact in the operational environment. This also provides an insight of the certification impact that these exceptional conditions pose at various criticality levels and design assurance levels and its implications in verifying and validating the designs.

  9. Software Safety Risk in Legacy Safety-Critical Computer Systems

    Science.gov (United States)

    Hill, Janice L.; Baggs, Rhoda

    2007-01-01

    Safety Standards contain technical and process-oriented safety requirements. Technical requirements are those such as "must work" and "must not work" functions in the system. Process-Oriented requirements are software engineering and safety management process requirements. Address the system perspective and some cover just software in the system > NASA-STD-8719.13B Software Safety Standard is the current standard of interest. NASA programs/projects will have their own set of safety requirements derived from the standard. Safety Cases: a) Documented demonstration that a system complies with the specified safety requirements. b) Evidence is gathered on the integrity of the system and put forward as an argued case. [Gardener (ed.)] c) Problems occur when trying to meet safety standards, and thus make retrospective safety cases, in legacy safety-critical computer systems.

  10. Medical education in cyberspace: critical considerations in the health system

    Science.gov (United States)

    YAZDANI, SHAHRAM; KHOSHGOFTAR, ZOHREH; AHMADY, SOLEIMAN; RASTEGARPOUR, HASSAN; FOROUTAN, SEYED ABBAS

    2017-01-01

    Introduction: Over the past few decades, two revolutionary approaches have emerged as a new form of medical education: Electronic Medical Education and Web-based Medical Education. A number of well-known medical institutions, such as Harvard and Johns Hopkins used a wide range of cyberspace capabilities to increase their competitiveness. Researchers have expressed that cyberspace will change health system’s main objective of training physicians and medical education. We conducted this study to identify the health system critical considerations on core issues, involving the development of medical education on cyberspace. Methods: In order to conduct this study, we observed the steps of a critical literature review, combined with the ‘Four-phase method’ adopted by Carnwell and Daly. We focused on particular literature on health and cyber system functions; it was associated with systemic approach. Results: We developed a six-level taxonomy, Cyber level, Governance level, Ministerial level, Organizational level, Program level and Performance level, as a key solution that can be applied for the success of medical education on cyberspace. The results were summarized and appraised in more details. Conclusion: Medical education on cyberspace is a complex interdisciplinary system. It is important that all aspects of the health systems be involved as integral to the development of cyber based medical education; without this convergence, we will be confused by the decisions made by others within the system. Health system should also communicate with those external sectors that are critical to achieving better learning on cyberspace. Integrated planning, governance and management of medical education in cyberspace are pivotal elements for the promotion. PMID:28124017

  11. Universality classes and critical phenomena in confined liquid systems

    Directory of Open Access Journals (Sweden)

    A.V. Chalyi

    2013-06-01

    Full Text Available It is well known that the similar universal behavior of infinite-size (bulk systems of different nature requires the same basic conditions: space dimensionality; number components of order parameter; the type (short- or long-range of the intermolecular interaction; symmetry of the fluctuation part of thermodynamical potential. Basic conditions of similar universal behavior of confined systems needs the same supplementary conditions such as the number of monolayers for a system confinement; low crossover dimensionality, i.e., geometric form of restricted volume; boundary conditions on limiting surfaces; physical properties under consideration. This review paper is aimed at studying all these conditions of similar universal behavior for diffusion processes in confined liquid systems. Special attention was paid to the effects of spatial dispersion and low crossover dimensionality. This allowed us to receive receiving correct nonzero expressions for the diffusion coefficient at the critical point and to take into account the specific geometric form of the confined liquid volume. The problem of 3D⇔2D dimensional crossover was analyzed. To receive a smooth crossover for critical exponents, the Kawasaki-like approach from the theory of mode coupling in critical dynamics was proposed. This ensured a good agreement between data of computer experiment and theoretical calculations of the size dependence of the critical temperature Tc(H of water in slitlike pores. The width of the quasi-elastic scattering peak of slow neutrons near the structural phase transition in the aquatic suspensions of plasmatic membranes (mesostructures with the typical thickness up to 10 nm was studied. It was shown that the width of quasi-elastic peak of neutron scattering decreases due to the process of cell proliferation, i.e., with an increase of the membrane size (including the membrane thickness. Thus, neutron studies could serve as an additional diagnostic test for the

  12. Far from equilibrium energy flow in quantum critical systems

    CERN Document Server

    Bhaseen, M J; Lucas, Andrew; Schalm, Koenraad

    2013-01-01

    We investigate far from equilibrium energy transport in strongly coupled quantum critical systems. Combining results from gauge-gravity duality, relativistic hydrodynamics, and quantum field theory, we argue that long-time energy transport occurs via a universal steady-state for any spatial dimensionality. This is described by a boosted thermal state. We determine the transport properties of this emergent steady state, including the average energy flow and its long-time fluctuations.

  13. Critical interfaces in geosynthetic multilayer liner system of a landfill

    Directory of Open Access Journals (Sweden)

    Qian Xuede

    2008-12-01

    Full Text Available This study is to identify the critical interface in a geosynthetic multilayer liner system by examining the effects of the interface shear strength of liner components, leachate level, leachate buildup cases, and peak and residual interface strengths. According to current landfill design procedures, conducting stability analysis along the same interface at both the back slope and base may result in a non-conservative result. The critical interfaces with the minimum factor of safety are generally found at different locations along the back slope and base. The critical interface for a multilayer liner system cannot simply be assumed during stability analysis. It can shift from one interface to another with changes in the leachate level and with different leachate buildup cases. The factor of safety for an interface with a high friction angle and low apparent cohesion generally drops much more quickly than it does under inverse conditions when the leachate level increases. The failure interface in a liner system under residual conditions is usually different from the failure interface under peak conditions.

  14. Battery-Aware Scheduling of Mixed Criticality Systems

    DEFF Research Database (Denmark)

    Wognsen, Erik Ramsgaard; Hansen, Rene Rydhof; Larsen, Kim Guldstrand

    2014-01-01

    hybrid system and study its performance under battery-aware scheduling strategies. We believe that this evaluation does not scale with current verification techniques for stochastic hybrid systems. Instead statistical model checking provides a viable alternative with statistical guarantees. Based on our......Wireless systems such as satellites and sensor networks are often battery-powered. To operate optimally they must therefore take the performance properties of real batteries into account. Additionally, these systems, and therefore their batteries, are often exposed to loads with uncertain timings....... Mixed criticality and soft real-time systems may accept deadline violations and therefore enable trade-offs and evaluation of performance by criteria such as the number of tasks that can be completed with a given battery. We model a task set in combination with the kinetic battery model as a stochastic...

  15. Analyzing Software Requirements Errors in Safety-Critical, Embedded Systems

    Science.gov (United States)

    Lutz, Robyn R.

    1993-01-01

    This paper analyzes the root causes of safety-related software errors in safety-critical, embedded systems. The results show that software errors identified as potentially hazardous to the system tend to be produced by different error mechanisms than non- safety-related software errors. Safety-related software errors are shown to arise most commonly from (1) discrepancies between the documented requirements specifications and the requirements needed for correct functioning of the system and (2) misunderstandings of the software's interface with the rest of the system. The paper uses these results to identify methods by which requirements errors can be prevented. The goal is to reduce safety-related software errors and to enhance the safety of complex, embedded systems.

  16. Critical relaxation with overdamped quasiparticles in open quantum systems

    Science.gov (United States)

    Lang, Johannes; Piazza, Francesco

    2016-09-01

    We study the late-time relaxation following a quench in an open quantum many-body system. We consider the open Dicke model, describing the infinite-range interactions between N atoms and a single, lossy electromagnetic mode. We show that the dynamical phase transition at a critical atom-light coupling is characterized by the interplay between reservoir-driven and intrinsic relaxation processes in the absence of number conservation. Above the critical coupling, small fluctuations in the occupation of the dominant quasiparticle mode start to grow in time, while the quasiparticle lifetime remains finite due to losses. Near the critical interaction strength, we observe a crossover between exponential and power-law 1 /τ relaxation, the latter driven by collisions between quasiparticles. For a quench exactly to the critical coupling, the power-law relaxation extends to infinite times, but the finite lifetime of quasiparticles prevents aging from appearing in two-times response and correlation functions. We predict our results to be accessible to quench experiments with ultracold bosons in optical resonators.

  17. Criticality in Two-Dimensional Quantum Systems: Tensor Network Approach

    CERN Document Server

    Ran, Shi-Ju; Li, Wei; Lewenstein, Maciej; Su, Gang

    2016-01-01

    Determination and characterization of criticality in two-dimensional (2D) quantum many-body systems belong to the most important challenges and problems of quantum physics. In this paper we propose an efficient scheme to solve this problem by utilizing the infinite projected entangled pair state (iPEPS), and tensor network (TN) representations. We show that the criticality of a 2D state is faithfully reproduced by the ground state (dubbed as boundary state) of a one-dimensional effective Hamiltonian constructed from its iPEPS representation. We demonstrate that for a critical state the correlation length and the entanglement spectrum of the boundary state are essentially different from those of a gapped iPEPS. This provides a solid indicator that allows to identify the criticality of the 2D state. Our scheme is verified on the resonating valence bond (RVB) states on kagom\\'e and square lattices, where the boundary state of the honeycomb RVB is found to be described by a $c=1$ conformal field theory. We apply ...

  18. Innovative technologies for dependable OTS-based critical systems challenges and achievements of the CRITICAL STEP project

    CERN Document Server

    Cotroneo, Domenico

    2013-01-01

    With practical examples from industry, this volume introduces the methods and tools adopted by the critical systems industry, which includes air traffic control and space exploration. It features 'off-the-shelf' systems designed by world-beating companies.

  19. Critical components in 0.14 THz communication systems

    CERN Document Server

    Shan, Guangcun; Zhu, Haoshen; Shek, Chan-Hung

    2012-01-01

    In the super-heterodyne terahertz communication system, the proper design of the critical components like mixers and filters are of great importance for enhancing its performance. In this work, some issues on our newly developed system setup design for 0.14 THz wireless communications and the key components subharmonic mixer (SHM) based on Schottky diode, as well as silicon micromachined bandpass rectangular waveguide filters are presented. According to ADS simulation, the optimum conversion loss of the 140 GHz SHM is 26 dB. And the silicon-micromachined rectangular waveguide filters have been fabricated and the measured lowset insertion losses are lower than 0.5 dB.

  20. An agent-based microsimulation of critical infrastructure systems

    Energy Technology Data Exchange (ETDEWEB)

    BARTON,DIANNE C.; STAMBER,KEVIN L.

    2000-03-29

    US infrastructures provide essential services that support the economic prosperity and quality of life. Today, the latest threat to these infrastructures is the increasing complexity and interconnectedness of the system. On balance, added connectivity will improve economic efficiency; however, increased coupling could also result in situations where a disturbance in an isolated infrastructure unexpectedly cascades across diverse infrastructures. An understanding of the behavior of complex systems can be critical to understanding and predicting infrastructure responses to unexpected perturbation. Sandia National Laboratories has developed an agent-based model of critical US infrastructures using time-dependent Monte Carlo methods and a genetic algorithm learning classifier system to control decision making. The model is currently under development and contains agents that represent the several areas within the interconnected infrastructures, including electric power and fuel supply. Previous work shows that agent-based simulations models have the potential to improve the accuracy of complex system forecasting and to provide new insights into the factors that are the primary drivers of emergent behaviors in interdependent systems. Simulation results can be examined both computationally and analytically, offering new ways of theorizing about the impact of perturbations to an infrastructure network.

  1. Critical configurations for a system of semidegenerate fermions

    CERN Document Server

    Argüelles, Carlos R; Fraga, Bernardo M O

    2014-01-01

    We study an isothermal system of semi-degenerate self-gravitating fermions in general relativity. Such systems present mass density solutions with a central degenerate core, a plateau and a tail which follows a power law behaviour $r^{-2}$. The different solutions are governed by the free parameters of the model: the degeneracy and temperature parameters at the center, and the particle mass $m$. We then analyze in detail the free parameter space for a fixed $m$ in the keV regime, by studying the one-parameter sequences of equilibrium configurations up to the critical point, which is represented by the maximum in a central density ($\\rho_0$) Vs. core mass ($M_c$) diagram. We show that for fully degenerate cores, the known expression for the critical core mass $M_c^{cr}\\propto m_{pl}^3/m^2$ is obtained, while instead for low degenerate cores, the critical core mass increases showing the temperature effects in a non linear way. The main result of this work is that when applying this theory to model the distribut...

  2. Mobile healthcare applications: system design review, critical issues and challenges.

    Science.gov (United States)

    Baig, Mirza Mansoor; GholamHosseini, Hamid; Connolly, Martin J

    2015-03-01

    Mobile phones are becoming increasingly important in monitoring and delivery of healthcare interventions. They are often considered as pocket computers, due to their advanced computing features, enhanced preferences and diverse capabilities. Their sophisticated sensors and complex software applications make the mobile healthcare (m-health) based applications more feasible and innovative. In a number of scenarios user-friendliness, convenience and effectiveness of these systems have been acknowledged by both patients as well as healthcare providers. M-health technology employs advanced concepts and techniques from multidisciplinary fields of electrical engineering, computer science, biomedical engineering and medicine which benefit the innovations of these fields towards healthcare systems. This paper deals with two important aspects of current mobile phone based sensor applications in healthcare. Firstly, critical review of advanced applications such as; vital sign monitoring, blood glucose monitoring and in-built camera based smartphone sensor applications. Secondly, investigating challenges and critical issues related to the use of smartphones in healthcare including; reliability, efficiency, mobile phone platform variability, cost effectiveness, energy usage, user interface, quality of medical data, and security and privacy. It was found that the mobile based applications have been widely developed in recent years with fast growing deployment by healthcare professionals and patients. However, despite the advantages of smartphones in patient monitoring, education, and management there are some critical issues and challenges related to security and privacy of data, acceptability, reliability and cost that need to be addressed.

  3. Critical Path-Based Thread Placement for NUMA Systems

    Energy Technology Data Exchange (ETDEWEB)

    Su, C Y; Li, D; Nikolopoulos, D S; Grove, M; Cameron, K; de Supinski, B R

    2011-11-01

    Multicore multiprocessors use a Non Uniform Memory Architecture (NUMA) to improve their scalability. However, NUMA introduces performance penalties due to remote memory accesses. Without efficiently managing data layout and thread mapping to cores, scientific applications, even if they are optimized for NUMA, may suffer performance loss. In this paper, we present algorithms and a runtime system that optimize the execution of OpenMP applications on NUMA architectures. By collecting information from hardware counters, the runtime system directs thread placement and reduces performance penalties by minimizing the critical path of OpenMP parallel regions. The runtime system uses a scalable algorithm that derives placement decisions with negligible overhead. We evaluate our algorithms and runtime system with four NPB applications implemented in OpenMP. On average the algorithms achieve between 8.13% and 25.68% performance improvement compared to the default Linux thread placement scheme. The algorithms miss the optimal thread placement in only 8.9% of the cases.

  4. Study on Critical Properties for CO2+Cosolvent Binary System and Ternary System

    Institute of Scientific and Technical Information of China (English)

    张敬畅; 吴向阳; 曹维良

    2002-01-01

    The performance of supercritical fluid (SCF) as a solvent can be greatly affected by addition of anentrainer to the system. In this study, a constant volume visual method is used to measure the critical point ofCO2+n-butyraldehyde, CO2+ i-butyraldehyde and CO2+alcohol binary systems and CO2+entrainer+trisodiumsalt of tri-(m-sulfonphenyl)phosphine (TPPTS) ternary systems, which provides us good theoretical basis for super-critical extraction and chemical reaction. The relationship between critical point and concentration of the entrainerare discussed. The phase behavior of binary system and that of ternary system are compared. The relationshipbetween the concentration of TPPTS and critical point of binary systems are also discussed.

  5. Identification of integrating and critically damped systems with time delay

    Institute of Scientific and Technical Information of China (English)

    BAJARANGBALI; Somanath MAJHI

    2015-01-01

    This paper presents identification of second order plus dead time (SOPDT) integrating and critically damped systems based on relay feedback testing. Relay with hysteresis is applied to the unknown system to get the sustained oscillations also called as limit cycle. The limit cycle parameters are utilized in mathematical expressions which are derived using state space technique so that exact process model parameters are estimated. As the relay with hysteresis helps in generating sustained oscillations and also reduces effect of measurement noise which is an important issue in system identification. Different types of processes in the form of transfer function models are considered to show the efficacy of the proposed method and results are compared with available methods in the literature with and without noise effect.

  6. Using event-B for critical device software systems

    CERN Document Server

    Singh, Neeraj Kumar

    2013-01-01

    Defining a new development life-cycle methodology, together with a set of associated techniques and tools to develop highly critical systems using formal techniques, this book adopts a rigorous safety assessment approach explored via several layers (from requirements analysis to automatic source code generation). This is assessed and evaluated via a standard case study: the cardiac pacemaker. Additionally a formalisation of an Electrocardiogram (ECG) is used to identify anomalies in order to improve existing medical protocols. This allows the key issue - that formal methods are not currently i

  7. Optimal Workflow Scheduling in Critical Infrastructure Systems with Neural Networks

    Directory of Open Access Journals (Sweden)

    S. Vukmirović

    2012-04-01

    Full Text Available Critical infrastructure systems (CISs, such as power grids, transportation systems, communication networks and water systems are the backbone of a country’s national security and industrial prosperity. These CISs execute large numbers of workflows with very high resource requirements that can span through different systems and last for a long time. The proper functioning and synchronization of these workflows is essential since humanity’s well-being is connected to it. Because of this, the challenge of ensuring availability and reliability of these services in the face of a broad range of operating conditions is very complicated. This paper proposes an architecture which dynamically executes a scheduling algorithm using feedback about the current status of CIS nodes. Different artificial neural networks (ANNs were created in order to solve the scheduling problem. Their performances were compared and as the main result of this paper, an optimal ANN architecture for workflow scheduling in CISs is proposed. A case study is shown for a meter data management system with measurements from a power distribution management system in Serbia. Performance tests show that significant improvement of the overall execution time can be achieved by ANNs.

  8. Critical Technologies for the Development of Future Space Elevator Systems

    Science.gov (United States)

    Smitherman, David V., Jr.

    2005-01-01

    A space elevator is a tether structure extending through geosynchronous earth orbit (GEO) to the surface of the earth. Its center of mass is in GEO such that it orbits the earth in sync with the earth s rotation. In 2004 and 2005, the NASA Marshall Space Flight Center and the Institute for Scientific Research, Inc. worked under a cooperative agreement to research the feasibility of space elevator systems, and to advance the critical technologies required for the future development of space elevators for earth to orbit transportation. The discovery of carbon nanotubes in the early 1990's was the first indication that it might be possible to develop materials strong enough to make space elevator construction feasible. This report presents an overview of some of the latest NASA sponsored research on space elevator design, and the systems and materials that will be required to make space elevator construction possible. In conclusion, the most critical technology for earth-based space elevators is the successful development of ultra high strength carbon nanotube reinforced composites for ribbon construction in the 1OOGPa range. In addition, many intermediate technology goals and demonstration missions for the space elevator can provide significant advancements to other spaceflight and terrestrial applications.

  9. FEATURES, EVENTS, AND PROCESSES: SYSTEM-LEVEL AND CRITICALITY

    Energy Technology Data Exchange (ETDEWEB)

    D.L. McGregor

    2000-12-20

    The primary purpose of this Analysis/Model Report (AMR) is to identify and document the screening analyses for the features, events, and processes (FEPs) that do not easily fit into the existing Process Model Report (PMR) structure. These FEPs include the 3 1 FEPs designated as System-Level Primary FEPs and the 22 FEPs designated as Criticality Primary FEPs. A list of these FEPs is provided in Section 1.1. This AMR (AN-WIS-MD-000019) documents the Screening Decision and Regulatory Basis, Screening Argument, and Total System Performance Assessment (TSPA) Disposition for each of the subject Primary FEPs. This AMR provides screening information and decisions for the TSPA-SR report and provides the same information for incorporation into a project-specific FEPs database. This AMR may also assist reviewers during the licensing-review process.

  10. Critical Education for Systemic Change: A World-Systems Analysis Perspective

    Science.gov (United States)

    Griffiths, Tom G.

    2015-01-01

    This paper both draws on, and seeks to apply, world-systems analysis to a broad, critical education project that builds mass schooling's potential contribution to the process of world-systemic change. In short, this is done by first setting out the world-systems analysis account of the current state, and period of transition, of the capitalist…

  11. Critical parameters for coarse coal underground slurry haulage systems

    Energy Technology Data Exchange (ETDEWEB)

    Maynard, D.P.

    1981-02-15

    This report describes the basic parameters which directly influence the behavior of a coal slurry pipeline transportation system and determine the limitations of the system performance. The purpose of this technology assessment is to provide an identification and understanding of the critical factors which must be given consideration in the design and evaluation of such a slurry haulage system intended for use in an underground coal mine. The slurry haulage system will be utilized to satisfy the transportation requirements of conveying, in a pipeline, the coal mined by a continuous mining machine to a storage location near the mine entrance or to a coal preparation plant located on the surface. Coal-water slurries, particularly those consisting of homogeneous suspensions of small particles, frequently behave as non-Newtonian, Bingham-plastic fluids. For successful operation, slurry transport systems should be designed to operate in the turbulent flow regime and at a flow rate at least 30% greater than the deposition velocity. The deposition velocity is defined as the slurry flow rate at which the solid particles tend to settle in the pipe. Due to the importance of accurately determining the deposition velocity and the uncertainties of current methods for predicting the deposition velocity of coarse particle slurries, it is recommended that experimental efforts be performed as a part of the system design. The capacity of the haulage system should be compatible with the mine's projected coal output in order to avoid operational delays and the necessity for in-mine coal storage. The slurry pumps must generate sufficient discharge pressure to overcome the resultant friction losses in horizontal and vertical pipe sections and to satisfy the slurry hoisting requirements.

  12. The Military Critical Technologies Program's Space Systems Technologies

    Science.gov (United States)

    Wick, R.

    The major objectives of the Militarily Critical Technologies Program (MCTP) are to identify and characterize technologies by specific parameters including quantitative values and to assess worldwide technology capabilities. The MCTP program, which is sponsored by the office of the Deputy Under Secretary/ITS vice Under Secretary, develops the Militarily Critical Technologies List (MCTL) though the support of the Institute for Defense Analyses. This paper describes the MCTL and its Space Systems Technologies. It outlines the unique TWG process developed by the Institute for Defense Analyses (IDA) to support the MCTP. It also outlines the approach used to determine which technologies are included as well as how worldwide technology capability assessment for each technology is determined. Each TWG has a broad membership that includes representatives from government, industry and academia who are subject matter experts in their respective fields. Therefore, the TWG process provides a systematic, ongoing assessment and analysis of goods and technologies to determine technologies that are being developed worldwide that significantly enhance or degrade military capabilities.

  13. Applicability of the SCALE code system to MOX fuel transport systems for criticality safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Toshihiro; Naito, Yoshitaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Hayashi, Toshiaki; Takasugi, Masahiro; Natsume, Toshihiro; Tsuda, Kazuaki

    1996-11-01

    In order to ascertain feasibilities of the SCALE code system for MOX fuel transport systems, criticality analyses were performed for MOX fuel (Pu enrichment; 3.0 wt.%) criticality experiments at JAERI`s TCA and for infinite fuel rod arrays as parameters of Pu enrichment and lattice pitch. The comparison with a combination of the continuous energy Monte Carlo code MCNP and JENDL-3.2 indicated that the SCALE code system with GAM-THERMOS 123-group library can produce feasible results. Though HANSEN-ROACH 16-group library gives poorer results for MOS fuel transport systems, the errors are conservative except for high enriched fuels. (author)

  14. Critical factors in the implementation process of integrated management systems

    Directory of Open Access Journals (Sweden)

    Ademir Antonio Ferreira

    2015-09-01

    Full Text Available This study is the result of research whose purpose was to study the implementation process of integrated management systems, called ERP Enterprise Resource Planning in the business environment. This study, more specifically, tried to identify the variables in this process and that, somehow, made it easy or caused some type of difficulty implementing the system. Based on the mixed method approach (Creswell, 2003, the study was performed by means of the content analysis of technical and scientific publications about this theme and by means of a field research for data collection from primary sources. The content analysis was based on the per mile procedure by Bardin (1977, making it possible to identify critical factors that may be found in the implementation of ERP system projects. Primary data was collected from structured interviews with the managers in charge of the implementation of the system, in each of the 12 companies in different sectors of the economy and based in Brazil. Based on this information, it was possible to test the factors extracted from the content analysis and then develop a list of factors that may effectively influence the implementation process of the system. In order to recognize the possible relations between the selected factors, the Spearman (rsp correlation coefficient was applied and the multiple regression analysis was performed by means of the stepwise procedure. The purpose of the regression analysis was to determine the relation of the “Assessment of the Implementation” dependent variable with other dependent variables in the selected categories. The results of these analyses showed that the support of the top management, the communication process for the clear evidence of this support, the technical support of the ERP program provider together with the project team expertise, training and qualification processes of the team in the system operation are significantly correlated and relevant factors for a

  15. Dairy production system type and critical points of contamination

    Directory of Open Access Journals (Sweden)

    Gilberto Henrique Simões

    2015-12-01

    Full Text Available Current milk production includes a large diversity between systems, which generates difficulties in defining a microbiological standard. The adapted practical and hygienic-sanitary management methods are diverse and introduce great complexity into the production systems. Based on this scenario, the objective of this study was to evaluate the types of dairy production systems of western Parana and to quantify Staphylococcus sp in three critical points in the dairy cattle production systems: the milking machines, milkers’ hands, the cooling tanks and raw milk. A total of 35 samples of refrigerated raw milk were collected, and a questionnaire referring to hygienic and sanitary management was administered. All of the data were collected during the period from September to October 2012 and involved 35 properties in the municipality of Marechal Cândido Rondon – PR. From these data, five groups were formed based on cluster analysis (CHA. The multiple correspondence analysis (MCA presented in the first two dimensions, CP1 (81.43% and CP2 (36.87%, showed the relevance of the variables used, which are sanitary and production management methods, and contamination and control of mastitis, respectively (CP1 and CP2. We found average contamination with 9.9 x 101 CFU/cm2, 2.2x104 CFU/cm2, 28 CFU/ cm2 and 3.8x103 CFU/mL; for milking machines, milkers’ hands, cooling tanks and milk, respectively. The results reveal the presence of staphylococcal agent in dairy production systems regardless of the adopted hygiene and health management protocols. The guidance, planning and adaptation of hygiene and health management systems can significantly improve the microbiological quality of the milk produced, both qualitatively and quantitatively.

  16. Existence of solutions for critical elliptic systems with boundary singularities

    Directory of Open Access Journals (Sweden)

    Jianfu Yang

    2013-04-01

    Full Text Available This article concerns the existence of positive solutions to the nonlinear elliptic system involving critical Hardy-Sobolev exponent $$displaylines{ -Delta u= frac{2lambdaalpha}{alpha+eta} frac{u^{alpha-1} v^eta}{|pi(x|^s}- u^p, quad hbox{in } Omega,cr -Delta v= frac{2lambdaeta}{alpha+eta} frac{u^alpha v^{eta-1}}{|pi(x|^s}- v^p, quad hbox{in } Omega,cr u>0,quad v>0, quad hbox{in } Omega,cr u=v=0, quad hbox{on } partialOmega, }$$ where $Ngeq 4$ and $Omega$ is a $C^1$ bounded domain in $mathbb{R}^N$, $01$, $lambda>0$ and $1leq p

  17. A Study on the Planning of Technology Development and Research for Generation IV Nuclear Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Moon Hee; Kim, H. R.; Kim, H. J. and others

    2005-08-15

    This study aimed at the planning the domestic technology development of the Gen IV and the formulating the international collaborative project contents and executive plan for 'A Validity Assessment and Policies of the R and D of Generation IV Nuclear Energy Systems'. The results of the study include follows; - Survey of the technology state in the fields of the Gen IV system specific technologies and the common technologies, and the plans of the international collaborative research - Drawing up the executive research and development plan by the experts of the relevant technology field for the systems which Korean will participate in. - Formulating the effective conduction plan of the program reflecting the view of the experts from the industry, the university and the research institute. - Establishing the plan for estimation of the research fund and the manpower for the efficient utilization of the domestic available resources. This study can be useful material for evaluating the appropriateness of the Korea's participation in the international collaborative development of the Gen IV, and can be valuably utilized to establish the strategy for the effective conduction of the program. The executive plan of the research and development which was produced in this study will be used to the basic materials for the establishing the guiding direction and the strategic conduction of the program when the research and development is launched in the future.

  18. A PEDAGOGICAL CRITICAL REVIEW OF ONLINE LEARNING SYSTEM

    Directory of Open Access Journals (Sweden)

    Dwi SULISWORO

    2016-08-01

    Full Text Available E-learning which have various shapes such as blog, classroom learning which is facilitated the World Wide Web; a mix of online instruction and meeting the class known as additional models or hybrid; or the full online experience, where all assessment and instruction is done electronically. Object relationship of learning and constructivist educational philosophy and confirmed that online learning has the orientation which is basically a constructivist ideology, where the combination of some of the knowledge is an inquiry-oriented activities and authentic and also promote the progress of the construction of new knowledge. Description of the online learning system in theory and practice can be illustrated in a few examples that have been found in the research that has been done and found new discoveries obtained in the study, but not everything can be done because of several factors. Please note that the components in the online learning system can serve as a learning system which is very strong influence on learning in the class. The objective of this research is to a pedagogical critical review of online learning system in theory and practice that can be applied by teachers in the teaching process in the classroom. The results obtained in this study were teachers and students need extra effort to make online classes and virtual. Further research is needed on appropriate strategies in order to determine the next result is more useful. There some advices for any studies that discuss online learning system are done in certain areas, namely the use of electricity and other disciplines such as social and humanities.

  19. Licensing process for safety-critical software-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Haapanen, P. [VTT Automation, Espoo (Finland); Korhonen, J. [VTT Electronics, Espoo (Finland); Pulkkinen, U. [VTT Automation, Espoo (Finland)

    2000-12-01

    System vendors nowadays propose software-based technology even for the most critical safety functions in nuclear power plants. Due to the nature of software faults and the way they cause system failures new methods are needed for the safety and reliability evaluation of these systems. In the research project 'Programmable automation systems in nuclear power plants (OHA)', financed together by the Radiation and Nuclear Safety Authority (STUK), the Ministry of Trade and Industry (KTM) and the Technical Research Centre of Finland (VTT), various safety assessment methods and tools for software based systems are developed and evaluated. As a part of the OHA-work a reference model for the licensing process for software-based safety automation systems is defined. The licensing process is defined as the set of interrelated activities whose purpose is to produce and assess evidence concerning the safety and reliability of the system/application to be licensed and to make the decision about the granting the construction and operation permissions based on this evidence. The parties of the licensing process are the authority, the licensee (the utility company), system vendors and their subcontractors and possible external independent assessors. The responsibility about the production of the evidence in first place lies at the licensee who in most cases rests heavily on the vendor expertise. The evaluation and gauging of the evidence is carried out by the authority (possibly using external experts), who also can acquire additional evidence by using their own (independent) methods and tools. Central issue in the licensing process is to combine the quality evidence about the system development process with the information acquired through tests, analyses and operational experience. The purpose of the licensing process described in this report is to act as a reference model both for the authority and the licensee when planning the licensing of individual applications

  20. Current status and future prospective of advanced radiation resistant oxide dispersion strengthened steel (ARROS) development for nuclear reactor system applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Kyu; Noh, Sang Hoon; Kang, Suk Hoon; Park, Jin Ju; Jin, Hyun Ju; Lee, Min Ku; Jang, Jin Sugn; Rhee, Chang Kyu [Nuclear Materials Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-04-15

    As one of the Gen-IV nuclear energy systems, a sodium-cooled fast reactor (SFR) is being developed at the Korea Atomic Energy Research Institute. As a long-term national research project, advanced radiation resistant oxide dispersion strengthened steel (ARROS) is being developed as an in-core fuel cladding tube material for a SFR in the future. In this paper, the current status of ARROS development is reviewed and its future prospective is discussed.

  1. Control of finite critical behaviour in a small-scale social system

    Science.gov (United States)

    Daniels, Bryan C.; Krakauer, David C.; Flack, Jessica C.

    2017-01-01

    Many adaptive systems sit near a tipping or critical point. For systems near a critical point small changes to component behaviour can induce large-scale changes in aggregate structure and function. Criticality can be adaptive when the environment is changing, but entails reduced robustness through sensitivity. This tradeoff can be resolved when criticality can be tuned. We address the control of finite measures of criticality using data on fight sizes from an animal society model system (Macaca nemestrina, n=48). We find that a heterogeneous, socially organized system, like homogeneous, spatial systems (flocks and schools), sits near a critical point; the contributions individuals make to collective phenomena can be quantified; there is heterogeneity in these contributions; and distance from the critical point (DFC) can be controlled through biologically plausible mechanisms exploiting heterogeneity. We propose two alternative hypotheses for why a system decreases the distance from the critical point. PMID:28186194

  2. Health system reform in Mexico: a critical review.

    Science.gov (United States)

    Laurell, Asa Cristina

    2007-01-01

    Last year Lancet published a series of articles on Mexico's 2004 health system reform. This article reviews the reform and its presentation in the Lancet series. The author sees the 2004 reform as a continuation of those initiated in 1995 at the largest public social security institute and in 1996 at the Ministry of Health, following the same conceptual design: "managed competition". The cornerstone of the 2004 reform-the voluntary Popular Health Insurance (PHI)--will not resolve the problems of the public health care system. The author assesses the robustness and validity of the evidence on which the 2004 reform is based, noting some inconsistencies and methodological errors in the data analysis and in the construction of the "effective coverage" index. Finally, some predictions about the future of PHI are outlined, given its intrinsic weaknesses. The next two or three years are critical for the viability of PHI: both families and states will face increasing difficulties in paying the insurance premium; health infrastructure and staff are insufficient to guarantee the health package services; and the private service contracting will further strain state health ministries' ability to strengthen service supply. Moreover, redistribution of federal health expenditure favoring PHI at the cost of the Social Security Institute will further endanger public health care delivery.

  3. Critical Behavior in Light Nuclear Systems: (I) Experimental Aspects

    CERN Document Server

    Ma, Y G; Wada, R; Hagel, K; Wang, J; Keutgen, T; Majka, Z; Murray, M; Qin, L; Smith, P; Alfaro, R; Cibor, J; Cinausero, M; Masri, Y E; Fabris, D; Fioretto, E; Keksis, A L; Lunardon, M; Makeev, A; Marie, N; Martin, E; Martínez-Davalos, A; Menchaca-Rocha, A; Nebbia, G; Prete, G; Rizzi, V; Ruangma, A; Shetty, D V; Souliotis, G A; Staszel, P; Veselsky, M; Viesti, G; Winchester, E M; Yennello, S J

    2004-01-01

    An extensive experimental survey of the features of the disassembly of a small quasi-projectile system with $A \\sim$ 36, produced in the reactions of 47 MeV/nucleon $^{40}$Ar + $^{27}$Al, $^{48}$Ti and $^{58}$Ni, has been carried out. Nuclei in the excitation energy range of 1-9 MeV/u have been investigated employing a new method to reconstruct the quasi-projectile source. At an excitation energy $\\sim$ 5.6 MeV/nucleon many observables indicate the presence of maximal fluctuations in the de-excitation processes. The fragment topological structure shows that the rank sorted fragments obey Zipf's law at the point of largest fluctuations providing another indication of a liquid gas phase transition. The caloric curve for this system shows a monotonic increase of temperature with excitation energy and no apparent plateau. The temperature at the point of maximal fluctuations is $8.3 \\pm 0.5$ MeV. Taking this temperature as the critical temperature and employing the caloric curve information we have extracted the c...

  4. Integrated Design and Analysis Environment for Safety Critical Human-Automation Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight deck systems, like many safety critical systems, often involve complex interactions between multiple human operators, automated subsystems, and physical...

  5. Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk.

    Science.gov (United States)

    Guttal, Vishwesha; Raghavendra, Srinivas; Goel, Nikunj; Hoarau, Quentin

    2016-01-01

    Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms.

  6. Determination of critical micelle concentration with the rotating sample system.

    Science.gov (United States)

    Kao, Linus T; Shetty, Gautam N; Gratzl, Miklós

    2008-12-01

    A novel experimental approach using the rotating sample system (RSS) is proposed here for the determination of the critical micelle concentration (CMC) of surfactants. The RSS has been conceived in our laboratory as a convection platform for physicochemical studies and analyses in microliter-sized sample drops. The scheme allows for vigorous rotation of the drop despite its small size through efficient air-liquid mechanical coupling. Thus, changes in surface properties of aqueous samples result in corresponding modulation of the hydrodynamic performance of the RSS, which can be utilized to investigate interfacial phenomena. In this work, we demonstrate that the RSS can be used to study the effects of surfactants on the surface and in the bulk of very small samples with hydrodynamic electrochemistry. Potassium ferrocyanide is employed here with cyclic voltammetry to probe the air-water interface of solutions containing Triton X-100. The CMC of this surfactant determined using this approach is 140 ppm, which agrees well with reported values obtained with conventional methods in much larger samples. The results also demonstrate that besides the CMC, variations in bulk rheological properties can also be investigated in very small specimens using the RSS with a simple method.

  7. The Microcirculation System in Critical Conditions Caused by Abdominal Sepsis

    Directory of Open Access Journals (Sweden)

    S. L. Kan

    2011-01-01

    Full Text Available Objective: to evaluate the microcirculation system in critical conditions caused by abdominal sepsis for a further differentiated approach to intensive care. Subjects and methods. Twenty-four patients with abdominal sepsis (mean age 42.9±0.9 years were examined; a control group consisted of 35 apparently healthy individuals (mean age 40.1±2.1 years. Over 11 days, the microcirculatory bed was evaluated by cutaneous laser Doppler flowmetry by means of a ЛАКК-02 laser capillary blood flow analyzer made in the Russian Federation (LAZMA Research-and-Production Association, by using a basic light guide for percutaneous microcirculation studies. Results. Throughout the study, tissue blood perfusion remained in the patients with sepsis due to the higher effect of mainly active components of vascular tone regulation on the microvascular bed. In a poor outcome, there was a reduction in both active and passive regulatory effects on tissue perfusion chiefly due to local (myogenic factors. Conclusion. The findings suggest that the patients with sepsis have microcirculatory regulation changes aimed at maintaining tissue perfusion. A follow-up of the microcirculation may be useful in choosing intensive care tactics and predicting disease outcome. Key words: sepsis, microcirculation, microvascular bed, micro blood flow, tissue perfusion.

  8. Validation of acid washes as critical control points in hazard analysis and critical control point systems.

    Science.gov (United States)

    Dormedy, E S; Brashears, M M; Cutter, C N; Burson, D E

    2000-12-01

    A 2% lactic acid wash used in a large meat-processing facility was validated as an effective critical control point (CCP) in a hazard analysis and critical control point (HACCP) plan. We examined the microbial profiles of beef carcasses before the acid wash, beef carcasses immediately after the acid wash, beef carcasses 24 h after the acid wash, beef subprimal cuts from the acid-washed carcasses, and on ground beef made from acid-washed carcasses. Total mesophilic, psychrotrophic, coliforms, generic Escherichia coli, lactic acid bacteria, pseudomonads, and acid-tolerant microorganisms were enumerated on all samples. The presence of Salmonella spp. was also determined. Acid washing significantly reduced all counts except for pseudomonads that were present at very low numbers before acid washing. All other counts continued to stay significantly lower (P HACCP plans and can significantly reduce the total number of microorganisms present on the carcass and during further processing.

  9. [Scoring system for early detection of critical illness can fail].

    Science.gov (United States)

    Kamstrup Christiansen, Lærke; Andreasen, Jo Bønding; Frederiksen, Christian Alcaraz; Juhl-Olsen, Peter; Sloth, Erik

    2013-02-18

    A 57-year old male underwent elective aortic valve replacement. The immediate post-operative course was uneventful and the patient was discharged with the lowest possible score on a newly implemented scale for early detection of critical illness. The following day he was readmitted with dyspnoea. The critical illness score was still low despite ultrasonic demonstration of a large pericardial effusion requiring drainage. We are concerned that the widely adopted critical illness scale is not sufficiently sensitive for cardiac surgery patients and advocate the use of point-of-care ultrasound.

  10. Control of critical behavior in a small-scale social system

    CERN Document Server

    Daniels, Bryan C; Flack, Jessica C

    2016-01-01

    Over the last decade new technologies for making large numbers of fine-grained measurements have led to the surprising discovery that many biological systems sit near a critical point. These systems are potentially more adaptive in that small changes to component behavior can induce large-scale changes in aggregate structure and function. Accounting for criticality remains a challenge as sensitivity to perturbation suggests a lack of robustness. Furthermore, change induced by perturbation may not be adaptive. Complicating matters further critical phenomena can result from history-dependent stochastic processes. A question central to distinguishing among these conflicting views of criticality is to what degree criticality can be controlled by the components of the system. We address the control of criticality using data on conflict dynamics and fight sizes from an animal society model system (Macaca nemestrina, n=48). The system is fundamentally finite so we operationalize criticality in information theoretic ...

  11. Dependability analysis of a safety critical system the LHC beam dumping system at CERN

    CERN Document Server

    Filippini, R

    2006-01-01

    This thesis presents the dependability study of the Beam Dumping System of the Large Hadron Collider (LHC), the high energy particle accelerator to be commissioned at CERN in summer 2007. There are two identical, independent LHC Beam Dumping Systems (LBDS), one per LHC beam, each consisting of a series of magnets that extract the particle beam from the LHC ring into the extraction line leading to the absorbing block. The consequences of a failure within the LBDS can be very severe. This risk is reduced by applying redundancy to the design of the most critical components and on-line surveillance that, in case of a detected failure, issues a safe operation abort, called false beam dump. The system has been studied applying Failure Modes Effects and Criticality Analysis (FMECA) and reliability prediction. The system failure processes have been represented with a state transition diagram, governed by a Markov regenerative stochastic process, and analysed for different operational scenarios for one year of operati...

  12. Maintaining Mission Critical Systems in a 247 Environment

    CERN Document Server

    Curtis, Peter M

    2011-01-01

    "This book is meant to offer Architects, Property Mangers, Facility Managers, Building Engineers, Information Technology Professionals, Data Center Personnel, Electrical & Mechanical Technicians and students in undergraduate, graduate, or continuing education programs relevant insight into the Mission Critical Environment with an emphasis on business resiliency, data center efficiency, and green power technology. Industry improvements, standards, and techniques have been incorporated into the text and address the latest issues prevalent in the Mission Critical Industry. An emphasis on green technologies and certifications is presented throughout the book. In addition, a description of the United States energy infrastructure's dependency on oil, in relation to energy security in the mission critical industry, is discussed. In conjunction with this, either a new chapter will be created on updated policies and regulations specifically related to the mission critical industry or updates to policies and regula...

  13. Towards validation of criticality calculations for systems with MOX powders

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, Tatiana [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France)], E-mail: tatiana.ivanova@irsn.fr; Rouyer, Veronique [Institut de Radioprotection et de Surete Nucleaire, Fontenay-aux-Roses (France); Rozhikhin, Yevgeniy; Tsiboulia, Anatoly [Institute for Physics and Power Engineering, Obninsk (Russian Federation)

    2009-04-15

    A series of experiments referred to as BFS/MOX was conducted in the BFS-1 experimental facility at IPPE, Russia. The program was designed to provide a basis for validation of criticality calculations for MOX fuel manufacturing processes and particularly those with low-moderated MOX fissile material. An extensive experimental program was performed, including criticality and reactor-type parameter measurements. The experiments were evaluated, peer reviewed, and analyzed with various codes and cross section data. The criticality validation study was performed employing a sensitivity/uncertainty technique based on the generalized linear least squares method. This paper briefly describes the experimental program, shows different tools' performance when calculating criticality for the BFS/MOX configurations, and focuses upon the validation study and results for generic applications with weapons-grade plutonium.

  14. Critical points and dynamic systems with planar hexagonal symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ning [Faculty of Information and Control Engineering, Shenyang Jianzhu University, Shenyang 110168 (China)]. E-mail: n_chen@126.com; Meng Fan Yu [Faculty of Information and Control Engineering, Shenyang Jianzhu University, Shenyang 110168 (China)

    2007-05-15

    In this investigation, we detect and utilize critical points of functions with hexagonal symmetry in order to study their dynamics. The asymmetric unit in a parallelogram lattice is chosen as the initial searching region for a critical point set in a dynamic plane. The accelerated direct search algorithm is used within the parallelogram lattice to search for the critical points. Parameter space is separated into regions (chaotic, periodic or mixed) by the Ljapunov exponents of the critical points. Then the generalized Mandelbrot set (M-set), which is a cross-section of the parameter space, is constructed. Many chaotic attractors and filled-in Julia sets can be generated by using parameters from this kind of M-sets.

  15. Parametric Optimization of Some Critical Operating System Functions--An Alternative Approach to the Study of Operating Systems Design

    Science.gov (United States)

    Sobh, Tarek M.; Tibrewal, Abhilasha

    2006-01-01

    Operating systems theory primarily concentrates on the optimal use of computing resources. This paper presents an alternative approach to teaching and studying operating systems design and concepts by way of parametrically optimizing critical operating system functions. Detailed examples of two critical operating systems functions using the…

  16. Self-organized criticality as a fundamental property of neural systems

    Directory of Open Access Journals (Sweden)

    Janina eHesse

    2014-09-01

    Full Text Available The neural criticality hypothesis states that the brain may be poised in a critical state at a boundary between different types of dynamics. Theoretical and experimental studies show that critical systems often exhibit optimal computational properties, suggesting the possibility that criticality has been evolutionarily selected as a useful trait for our nervous system. Evidence for criticality has been found in cell cultures, brain slices, and anesthetized animals. Yet, inconsistent results were reported for recordings in awake animals and humans, and current results point to open questions about the exact nature and mechanism of criticality, as well as its functional role. Therefore, the criticality hypothesis has remained a controversial proposition. Here, we provide an account of the mathematical and physical foundations of criticality. In the light of this conceptual framework, we then review and discuss recent experimental studies with the aim of identifying important next steps to be taken and connections to other fields that should be explored.

  17. Calculation of critical fault recovery time for nonlinear systems based on region of attraction analysis

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Blanke, Mogens

    2014-01-01

    In safety critical systems, the control system is composed of a core control system with a fault detection and isolation scheme together with a repair or a recovery strategy. The time that it takes to detect, isolate, and recover from the fault (fault recovery time) is a critical factor in safety...... of a system. It must be guaranteed that the trajectory of a system subject to fault remains in the region of attraction (ROA) of the post-fault system during this time. This paper proposes a new algorithm to compute the critical fault recovery time for nonlinear systems with polynomial vector elds using sum...

  18. 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.

  19. DNS as critical infrastructure, the energy system case study

    NARCIS (Netherlands)

    Casalicchio, E.; Caselli, M.; Coletta, A.; Nai Fovino, I.; Gheorghe, A.V.

    2013-01-01

    Modern critical infrastructures (e.g., power plants, energy grids, oil pipelines, etc.), make nowadays extensive use of information and communication technologies (ICT). As a direct consequence their exposure to cyber-attacks is becoming a matter of public security. In this paper, we analyse a parti

  20. SOLUTION OF A CLASS OF NONHOMOGENEOUS ELLIPTIC SYSTEM INVOLVING CRITICAL SOBOLEV EXPONENT

    Institute of Scientific and Technical Information of China (English)

    ZhangGuoqing; LiuSanyang

    2005-01-01

    In this paper, we discuss the problem of solving a class of nonhomogeneous semilinear elliptic system with critical Sobolev exponent changing into one of critical points of some given functional. Using Nehari technique, the given functional attain its minimum by adding suitable constraints, and the minimal point becomes a critical point of the original functional after eliminating the added constraints, thus the solution of the nonhomogeneous elliptic system is obtained.

  1. 48 CFR 1852.246-70 - Mission Critical Space System Personnel Reliability Program.

    Science.gov (United States)

    2010-10-01

    ... System Personnel Reliability Program. 1852.246-70 Section 1852.246-70 Federal Acquisition Regulations... Reliability Program. As prescribed in 1846.370(a), insert the following clause: Mission Critical Space System Personnel Reliability Program (MAR 1997) (a) In implementation of the Mission Critical Space...

  2. Developments in solar still desalination systems: A critical review

    KAUST Repository

    Ayoub, George M.

    2012-10-01

    Solar still desalination uses a sustainable and pollution-free source to produce high-quality water. The main limitation is low productivity and this has been the focus of intensive research. A major concern while increasing productivity is to maintain economic feasibility and simplicity. The authors present a critical review of the research work conducted on solar stills development. Studies addressing each parameter of concern are grouped together and results compared. Novelty in design and newly introduced features are presented. Modeling efforts of flow circulation within the still and methods to estimate internal heat transfer coefficients are discussed and future research needs are outlined. © 2012 Taylor & Francis Group, LLC.

  3. Clinical application of adhesive systems - a critical review: biomimetic approach

    OpenAIRE

    Ricci,Weber Adad; LUCAS,Camila de Paula Telles Pires; PIVETA,Ana Cláudia Gabrielli; NAGLE,Maurício Meirelles; Montandon, Andréia Affonso Barretto

    2015-01-01

    The various functions and clinical applications of adhesive systems have become a fundamental part of restorative treatment. The biggest challenge for such systems is to provide adequate adhesion to the different tissues, which can be very diverse in nature. When choosing the appropriate adhesive system, the dentist should be familiar with the origin, composition, action mechanism and method of application of each system. The commercially available products and their high technical status hav...

  4. A universal indicator of critical state transitions in noisy complex networked systems

    OpenAIRE

    Junhao Liang; Yanqing Hu; Guanrong Chen; Tianshou Zhou

    2017-01-01

    Critical transition, a phenomenon that a system shifts suddenly from one state to another, occurs in many real-world complex networks. We propose an analytical framework for exactly predicting the critical transition in a complex networked system subjected to noise effects. Our prediction is based on the characteristic return time of a simple one-dimensional system derived from the original higher-dimensional system. This characteristic time, which can be easily calculated using network data,...

  5. A Critical Systems Approach to Social Learning: Building Adaptive Capacity in Social, Ecological, Epistemological (SEE Systems

    Directory of Open Access Journals (Sweden)

    Daniel D. P. McCarthy

    2011-09-01

    Full Text Available This paper presents a conceptual tool, or heuristic, for describing the epistemological context for social learning within complex social-ecological systems. The heuristic integrates several definitions of social learning that emphasize the importance of critical reflection and its collaborative nature and that it is rooted in and oriented toward practice through social interactions. The conceptual tool is useful in identifying and conceptually mapping different perspectives based on types of learning described along three dimensions: typology of knowledge; different levels of critical reflection; and scale. The heuristic was originally developed in the context of an environmental planning process in southern Ontario, Canada, and is applied to identifying barriers and bridges to social learning in the case of flood damage reduction in a remote First Nations community in northern Ontario, Canada.

  6. A formula for crossing probabilities of critical systems inside polygons

    Science.gov (United States)

    Flores, S. M.; Simmons, J. J. H.; Kleban, P.; Ziff, R. M.

    2017-02-01

    In this article, we use our results from Flores and Kleban (2015 Commun. Math. Phys. 333 389-434, 2015 Commun. Math. Phys. 333 435-81, 2015 Commun. Math. Phys. 333 597-667, 2015 Commun. Math. Phys. 333 669-715) to generalize known formulas for crossing probabilities. Prior crossing results date back to Cardy’s prediction of a formula for the probability that a percolation cluster in two dimensions connects the left and right sides of a rectangle at the percolation critical point in the continuum limit (Cardy 1992 J. Phys. A: Math. Gen. 25 L201-6). Here, we predict a new formula for crossing probabilities of a continuum limit loop-gas model on a planar lattice inside a 2N-sided polygon. In this model, boundary loops exit and then re-enter the polygon through its vertices, with exactly one loop passing once through each vertex, and these loops join the vertices pairwise in some specified connectivity through the polygon’s exterior. The boundary loops also connect the vertices through the interior, which we regard as a crossing event. For particular values of the loop fugacity, this formula specializes to FK cluster (resp. spin cluster) crossing probabilities of a critical Q-state random cluster (resp. Potts) model on a lattice inside the polygon in the continuum limit. This includes critical percolation as the Q  =  1 random cluster model. These latter crossing probabilities are conditioned on a particular side-alternating free/fixed (resp. fluctuating/fixed) boundary condition on the polygon’s perimeter, related to how the boundary loops join the polygon’s vertices pairwise through the polygon’s exterior in the associated loop-gas model. For Q\\in ≤ft\\{2,3,4\\right\\} , we compare our predictions of these random cluster (resp. Potts) model crossing probabilities in a rectangle (N  =  2) and in a hexagon (N  =  3) with high-precision computer simulation measurements. We find that the measurements agree with our predictions very

  7. Verification and Validation of Flight Critical Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Verification and Validation is a multi-disciplinary activity that encompasses elements of systems engineering, safety, software engineering and test. The elements...

  8. Critical review of kraft recovery boiler air systems

    Energy Technology Data Exchange (ETDEWEB)

    Mac Callum, C.; Blackwell, B.R.

    1987-10-01

    Combustion air systems offered by major world suppliers of kraft recovery boilers are reviewed. A preliminary mathematical analysis of the air-jet trajectories in the furnace indicated that the conventional air systems leave room for improving the jet penetration into the furnace core. 9 refs., 2 figs., 1 tab.

  9. Design of Mixed-Criticality Applications on Distributed Real-Time Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian

    the concept of virtual links, and temporal separation, enforced through schedule tables for TT messages and bandwidth allocation for RC messages. The objective of this thesis is to develop methods and tools for distributed mixed-criticality real-time systems. At the processor level, we are interested......A mixed-criticality system implements applications of different safety-criticality levels onto the same platform. In such cases, the certification standards require that applications of different criticality levels are protected so they cannot influence each other. Otherwise, all tasks have...... to be developed and certified according to the highest criticality level, dramatically increasing the development costs. In this thesis we consider mixed-criticality real-time applications implemented on distributed partitioned architectures. Partitioned architectures use temporal and spatial separation...

  10. Critical point quantities and integrability conditions for a class of quintic systems

    Institute of Scientific and Technical Information of China (English)

    刘一戎; 肖萍

    2004-01-01

    For a class of quintic systems, the first 16 critical point quantities are obtained by computer algebraic system Mathematica, and the necessary and sufficient conditions that there exists an exact integral in a neighborhood of the origin are also given. The technique employed is essentially different from usual ones. The recursive formula for computation of critical point quantities is linear and then avoids complex integral operations. Some results show an interesting contrast with the related results on quadratic systems.

  11. Do CASA systems satisfy consumers demands? A critical analysis.

    Science.gov (United States)

    Feitsma, H; Broekhuijse, M L W J; Gadella, B M

    2011-09-01

    Boar studs are often offered new technologies including several CASA (computer-assisted semen analysis) systems. However, independent information to assist their purchase decisions is not available. The systems accuracy and repeatability variation because of different factors can be evaluated through duplicate testing of semen samples and comparison of the results according to WHO standards for humans. This primary analysis and a thorough economic cost benefit evaluation will help to decide whether the purchase of a CASA system will be profitable for a boar stud. Our experience of implementing several CASA systems in the cooperative Dutch Artificial Insemination (AI) centres is used as a base for this discussion. © 2011 Blackwell Verlag GmbH.

  12. Analyzing Software Errors in Safety-Critical Embedded Systems

    Science.gov (United States)

    Lutz, Robyn R.

    1994-01-01

    This paper analyzes the root causes of safty-related software faults identified as potentially hazardous to the system are distributed somewhat differently over the set of possible error causes than non-safety-related software faults.

  13. Parameter optimization for tandemregenerative system based on critical path

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    For a tandem queue system, the regenerative path is constructed. In an inter-regeneration cycle, the sensitivity value of performance measure with respect to the adjustable parameter θ can be acquired based on a fixed length of observation. Furthermore, a new algorithm of parameter optimization for the tandem queue system is given,which requires less simulation and no analysis for the perturbation transmission and makes a better estimation for the sen sitivity.

  14. Critical exponent for a damped wave system with fractional integral

    Directory of Open Access Journals (Sweden)

    Mijing Wu

    2015-08-01

    Full Text Available We shall present the critical exponent $$ F(p, q,\\alpha:=\\max\\big\\{\\alpha+\\frac{(\\alpha+1(p+1}{pq-1}, \\alpha+\\frac{(\\alpha+1(q+1}{pq-1}\\big\\}-\\frac{1}{2} $$ for the Cauchy problem $$\\displaylines{ u_{tt}-u_{xx}+u_t=J_{0|t}^{\\alpha}(|v|^{p}, \\quad (t,x\\in\\mathbb{R}^{+}\\times\\mathbb{R},\\cr v_{tt}-v_{xx}+v_t=J_{0|t}^{\\alpha}(|u|^{q}, \\quad (t, x\\in\\mathbb{R}^{+}\\times\\mathbb{R},\\cr (u(0,x, u_t(0,x=(u_0(x,u_1(x, \\quad x\\in \\mathbb{R},\\cr (v(0,x, v_t(0,x=(v_0(x,v_1(x, \\quad x\\in \\mathbb{R},\\cr }$$ where $p,q\\geq 1$, $pq>1$ and $0<\\alpha<1/2$; that is, the small data global existence of solutions can be derived to the problem above if $F(p, q, \\alpha<0$. Furthermore, in the case of $F(p, q, \\alpha\\geq 0$ the non-existence of global solution can be obtained with the initial data having positive average value.

  15. Center Conditions and Bifurcation of Limit Cycles at Nilpotent Critical Point in a Quintic Lyapunov System

    Institute of Scientific and Technical Information of China (English)

    Feng LI; Yin Lai JIN

    2011-01-01

    In this paper,center conditions and bifurcation of limit cycles at the nilpotent critical point in a class of quintic polynomial differential system are investigated.With the help of computer algebra system MATHEMATICA,the first 8 quasi Lyapunov constants are deduced.As a result,the necessary and sufficient conditions to have a center are obtained.The fact that there exist 8 small amplitude limit cycles created from the three-order nilpotent critical point is also proved.Henceforth we give a lower bound of cyclicity of three-order nilpotent critical point for quintic Lyapunov systems.

  16. Damage Evaluation of Critical Components of Tilted Support Spring Nonlinear System under a Rectangular Pulse

    Directory of Open Access Journals (Sweden)

    Ningning Duan

    2015-01-01

    Full Text Available Dimensionless nonlinear dynamical equations of a tilted support spring nonlinear packaging system with critical components were obtained under a rectangular pulse. To evaluate the damage characteristics of shocks to packaged products with critical components, a concept of the damage boundary surface was presented and applied to a titled support spring system, with the dimensionless critical acceleration of the system, the dimensionless critical velocity, and the frequency parameter ratio of the system taken as the three basic parameters. Based on the numerical results, the effects of the frequency parameter ratio, the mass ratio, the dimensionless peak pulse acceleration, the angle of the system, and the damping ratio on the damage boundary surface of critical components were discussed. It was demonstrated that with the increase of the frequency parameter ratio, the decrease of the angle, and/or the increase of the mass ratio, the safety zone of critical components can be broadened, and increasing the dimensionless peak pulse acceleration or the damping ratio may lead to a decrease of the damage zone for critical components. The results may lead to a thorough understanding of the design principles for the tilted support spring nonlinear system.

  17. Mental health care delivery system in Greece: a critical overview.

    Science.gov (United States)

    Stefanis, C N; Madianos, M G

    1981-01-01

    The organizational profile of the mental health care delivery system in Greece is mainly characterized by centralization which is reflected in various functional parts of the system (uneven distribution of psychiatric beds and manpower, absence of psychiatric units in general hospitals serving a certain catchment area, lack of community-based psychiatric services, etc.) As a result of this centralized structure there is a centrifugal flow of the mentally ill patients toward Athens and Thessaloniki and consequently the existing possibilities for community-based care as an alternative to inpatient treatment are rather limited. Future immediate objectives of the national social policy planning should be based on decentralization and reorganization of the psychiatric services in order for the mental health delivery system to respond more effectively to the mental health needs of the Greek population.

  18. A mathematical framework for critical transitions: Bifurcations, fast-slow systems and stochastic dynamics

    Science.gov (United States)

    Kuehn, Christian

    2011-06-01

    Bifurcations can cause dynamical systems with slowly varying parameters to transition to far-away attractors. The terms “critical transition” or “tipping point” have been used to describe this situation. Critical transitions have been observed in an astonishingly diverse set of applications from ecosystems and climate change to medicine and finance. The main goal of this paper is to give an overview which standard mathematical theories can be applied to critical transitions. We shall focus on early-warning signs that have been suggested to predict critical transitions and point out what mathematical theory can provide in this context. Starting from classical bifurcation theory and incorporating multiple time scale dynamics one can give a detailed analysis of local bifurcations that induce critical transitions. We suggest that the mathematical theory of fast-slow systems provides a natural definition of critical transitions. Since noise often plays a crucial role near critical transitions the next step is to consider stochastic fast-slow systems. The interplay between sample path techniques, partial differential equations and random dynamical systems is highlighted. Each viewpoint provides potential early-warning signs for critical transitions. Since increasing variance has been suggested as an early-warning sign we examine it in the context of normal forms analytically, numerically and geometrically; we also consider autocorrelation numerically. Hence we demonstrate the applicability of early-warning signs for generic models. We end with suggestions for future directions of the theory.

  19. Blow-up Mechanism of Classical Solutions to Quasilinear Hyperbolic Systems in the Critical Case

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper deals with the blow-up phenomenon, particularly, the geometric blow-up mechanism, of classical solutions to the Cauchy problem for quasilinear hyperbolic systems in the critical case. We prove that it is still the envelope of the same family of characteristics which yields the blowup of classical solutions to the Cauchy problem in the critical case.

  20. Retention systems for extraoral maxillofacial prosthetic implants: a critical review.

    Science.gov (United States)

    Cobein, M V; Coto, N P; Crivello Junior, O; Lemos, J B D; Vieira, L M; Pimentel, M L; Byrne, H J; Dias, R B

    2017-05-25

    We describe the techniques available for retention of implant-supported prostheses: bar-clips, O-rings, and magnets. We present reported preferences and, although this is limited by the heterogeneity of methods used and patients studied, we hope we have identified the best retention systems for maxillofacial prosthetic implants. If practitioners know the advantages and disadvantages of each system, they can choose the most natural and comfortable prosthesis. We searched the PubMed and Scopus databases, and restricted our search to papers published 2001-13. MeSH terms used were Maxillofacial prosthesis and Craniofacial prosthesis OR Craniofacial prostheses. We found a total of 2630 papers, and after duplicates had been removed we analysed the rest and found 25 papers for review. Of these, 12 were excluded because they were case reports or non-systematic reviews. Of the remaining 13, 10 described group analyses and seemed appropriate to find practitioner's choices, as cited in the abstract (n=1611 prostheses). Three papers did not mention the type of prosthetic connection used, so were excluded. The most popular choices for different conditions were analysed, though the sites and retention systems were not specified in all 10 papers. The bar-clip system was the most used in auricular (6/10 papers) and nasal prostheses (4/10). For the orbital region, 6/10 favoured magnets. Non-osseointegrated mechanical or adhesive retention techniques are the least expensive and have no contraindications. When osseointegrated implants are possible, each facial region has a favoured system. The choice of system is influenced by two factors: standard practice and the abilities of the maxillofacial surgeon and maxillofacial prosthetist. Copyright © 2017 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  1. Achieving interoperability in critical IT and communication systems

    CERN Document Server

    Desourdis, Robert I

    2009-01-01

    Supported by over 90 illustrations, this unique book provides a detailed examination of the subject, focusing on the use of voice, data, and video systems for public safety and emergency response. This practical resource makes in-depth recommendations spanning technical, planning, and procedural approaches to provide efficient public safety response performance. You find covered the many approaches used to achieve interoperability, including a synopsis of the enabling technologies and systems intended to provide radio interoperability. Featuring specific examples nationwide, the book takes you

  2. National Plant Germplasm System: Critical Role of Customer Service

    Science.gov (United States)

    The National Plant Germplasm System (NPGS) conserves plant genetic resources, not only for use by future generations, but for immediate use by scientists and educators around the world. With a great deal of interaction between genebank curators and users of plant genetic resources, customer service...

  3. A Multiscale Modeling System: Developments, Applications, and Critical Issues

    Science.gov (United States)

    Tao, Wei-Kuo; Lau, William; Simpson, Joanne; Chern, Jiun-Dar; Atlas, Robert; Khairoutdinov, David Randall Marat; Li, Jui-Lin; Waliser, Duane E.; Jiang, Jonathan; Hou, Arthur; Lin, Xin; Peters-Lidard, Christa

    2009-01-01

    The foremost challenge in parameterizing convective clouds and cloud systems in large-scale models are the many coupled dynamical and physical processes that interact over a wide range of scales, from microphysical scales to the synoptic and planetary scales. This makes the comprehension and representation of convective clouds and cloud systems one of the most complex scientific problems in Earth science. During the past decade, the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) has pioneered the use of single-column models (SCMs) and cloud-resolving models (CRMs) for the evaluation of the cloud and radiation parameterizations in general circulation models (GCMs; e.g., GEWEX Cloud System Science Team 1993). These activities have uncovered many systematic biases in the radiation, cloud and convection parameterizations of GCMs and have led to the development of new schemes (e.g., Zhang 2002; Pincus et al, 2003; Zhang and Wu 2003; Wu et al. 2003; Liang and Wu 2005; Wu and Liang 2005, and others). Comparisons between SCMs and CRMs using the same large-scale forcing derived from field campaigns have demonstrated that CRMs are superior to SCMs in the prediction of temperature and moisture tendencies (e.g., Das et al. 1999; Randall et al 2003b; Xie et al. 2005).

  4. Department of Defense Systems Acquisition Management: Congressional Criticism and Concern

    Science.gov (United States)

    1974-05-01

    preparation period. Finally I want to thank my wife, Dolores , for her tolerance of my aca- demic preoccupation in I96O-61, 1966-67, and throughout the...policy: man on firing line adjusts to actual situation Washington finds out only occasionally, acci- dentally ; need dependable system to insure

  5. system hardening architecture for safer access to critical business ...

    African Journals Online (AJOL)

    eobe

    a computer system or to inject malicious code into it, aimed at causing harm to ... 34 No. 4, October 2015 789 safer access to stored data, and therefore, decrease in ..... Computer and Communication Engineering, Vol. 3,. Number 1, 2014, pp ...

  6. Customer Service: A Critical Factor in Library System Selection.

    Science.gov (United States)

    Machovec, George S.

    1993-01-01

    Describes factors in successful customer service programs that are pertinent to libraries choosing an integrated online library system. Topics discussed include quick response time; easy access to information; well-trained client representatives; low costs; cooperation with customers and vendors; and anticipating customer needs. (LRW)

  7. Integrated system for remotely monitoring critical physiological parameters

    Science.gov (United States)

    Alexakis, S.; Karalis, S.; Asvestas, P.

    2015-09-01

    Monitoring several human parameters (temperature, heart rate, blood pressure etc.) is an essential task in health care in hospitals as well as in home care. This paper presents the design and implementation of an integrated, embedded system that includes an electrocardiograph of nine leads and two channels, a digital thermometer for measuring the body temperature and a power supply. The system provides networking capabilities (wired or wireless) and is accessible by means of a web interface that allows the user to select the leads, as well as to review the values of heart rate (beats per minute) and body temperature. Furthermore, there is the option of saving all the data in a Micro SD memory card or in a Google Spreadsheet. The necessary analog circuits for signal conditioning (amplification and filtering) were manufactured on printed circuit boards (PCB). The system was built around Arduino Yun, which is a platform that contains a microcontroller and a microprocessor running a special LINUX distribution. Furthermore, the Arduino Yun provides the necessary network connectivity capabilities by means of the integrated Wi-Fi and Ethernet interfaces. The web interface was developed using HTML pages with JavaScript support. The system was tested on simulated data as well as real data, providing satisfactory accuracy regarding the measurement of the heart rate (±3 bpm error) and the temperature (±0.3°C error).

  8. Factors Critical to the Adoption of Career Guidance Systems.

    Science.gov (United States)

    Kester, Ralph J.; Howard, John, Jr.

    The study endeavors to describe, assess, and trace the progress of six high schools as the faculty and staff responded to the adoption of an innovative career guidance system. The study provides a model, a method, and some generalizations about factors influencing the process. The document is organized according to: (1) definitions of basic…

  9. Toward a Critical Theoretic Perspective in Information Systems.

    Science.gov (United States)

    Benoit, Gerald

    2002-01-01

    Considers the logico-analytic philosophy of library and information science (LIS); discusses Jurgen Habermas' theory of communicative action; examines how LIS, particularly research into librarian-patron interaction and information system design, favors an empiricist view of language and thus may be limiting its effectiveness; and suggests the…

  10. A Multiscale Modeling System: Developments, Applications, and Critical Issues

    Science.gov (United States)

    Tao, Wei-Kuo; Lau, William; Simpson, Joanne; Chern, Jiun-Dar; Atlas, Robert; Khairoutdinov, David Randall Marat; Li, Jui-Lin; Waliser, Duane E.; Jiang, Jonathan; Hou, Arthur; hide

    2009-01-01

    The foremost challenge in parameterizing convective clouds and cloud systems in large-scale models are the many coupled dynamical and physical processes that interact over a wide range of scales, from microphysical scales to the synoptic and planetary scales. This makes the comprehension and representation of convective clouds and cloud systems one of the most complex scientific problems in Earth science. During the past decade, the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) has pioneered the use of single-column models (SCMs) and cloud-resolving models (CRMs) for the evaluation of the cloud and radiation parameterizations in general circulation models (GCMs; e.g., GEWEX Cloud System Science Team 1993). These activities have uncovered many systematic biases in the radiation, cloud and convection parameterizations of GCMs and have led to the development of new schemes (e.g., Zhang 2002; Pincus et al, 2003; Zhang and Wu 2003; Wu et al. 2003; Liang and Wu 2005; Wu and Liang 2005, and others). Comparisons between SCMs and CRMs using the same large-scale forcing derived from field campaigns have demonstrated that CRMs are superior to SCMs in the prediction of temperature and moisture tendencies (e.g., Das et al. 1999; Randall et al 2003b; Xie et al. 2005).

  11. Relationship between the density of supercritical CO2 +ethanol binary system and its critical properties

    Institute of Scientific and Technical Information of China (English)

    张敬畅; 张建军; 曹维良

    2003-01-01

    The dependent relation between temperature and pressure of supercritical CO2 + ethanol binary system under the pressure range from 5 to 10 MPa with the variety of densities and mole fractions of ethanol that range from 0 to 2% was investigated by the static visual method in a constant volume. The critical temperature and pressure were experimentally determined simultaneously. The PTρ figures at different ethanol contents were described based on the determined pressure and temperature data, from which pressure of supercritical CO2 + ethanol binary system was found to increase linearly with the increasing temperature. P-T lines show certain convergent feature in a specific concentration of ethanol and the convergent points shift to the region of higher temperature and pressure with the increasing ethanol compositions. Furthermore, the effect of density and ethanol concentration on the critical point of CO2 + ethanol binary system was discussed in details. Critical points increase linearly with the increasing mole fraction of ethanol in specific density and critical points change at different densities. The critical compressibility factors Zc of supercritical CO2 + ethanol binary systems at different compositions of ethanol were calculated and Zc-ρ figure was obtained accordingly. It was found from Zc-ρ figure that critical compressibility factors of supercritical CO2 unitary or binary systems decline linearly with the increasing density, by which the critical point can be predicted precisely.

  12. Systems Engineering as a critical tool in mobile robot simulation

    Directory of Open Access Journals (Sweden)

    Citlalih Yollohtli Alejandra Gutiérrez Estrada

    2013-01-01

    Full Text Available This paper explains a mobile robot simulation process in a static scenario with obstacles, which generated a location map supported by various prototypes created throughout the project, used to analyze the behavior of autonomous navigation algorithms and implemented mapping. This project had the management and formalization support from Software Systems Engineering through the spiral lifecycle model, used to develop and test the intended processes and human reasoning. Each step of the spiral lifecycle model iteration considered the goals, artificial intelligence (AI and simulation aspects by identifying the robot’s purpose, as well as solution alternatives to define the methods to achieve the intended goals. As a project with a common objective for a multidisciplinary research group, the work and results obtained by means of systems engineering allowed tackling the interests of several end users and handling functional and non-functional requirements separately.

  13. International ranking systems for universities and institutions: a critical appraisal

    Directory of Open Access Journals (Sweden)

    Tatsioni Athina

    2007-10-01

    Full Text Available Abstract Background Ranking of universities and institutions has attracted wide attention recently. Several systems have been proposed that attempt to rank academic institutions worldwide. Methods We review the two most publicly visible ranking systems, the Shanghai Jiao Tong University 'Academic Ranking of World Universities' and the Times Higher Education Supplement 'World University Rankings' and also briefly review other ranking systems that use different criteria. We assess the construct validity for educational and research excellence and the measurement validity of each of the proposed ranking criteria, and try to identify generic challenges in international ranking of universities and institutions. Results None of the reviewed criteria for international ranking seems to have very good construct validity for both educational and research excellence, and most don't have very good construct validity even for just one of these two aspects of excellence. Measurement error for many items is also considerable or is not possible to determine due to lack of publication of the relevant data and methodology details. The concordance between the 2006 rankings by Shanghai and Times is modest at best, with only 133 universities shared in their top 200 lists. The examination of the existing international ranking systems suggests that generic challenges include adjustment for institutional size, definition of institutions, implications of average measurements of excellence versus measurements of extremes, adjustments for scientific field, time frame of measurement and allocation of credit for excellence. Conclusion Naïve lists of international institutional rankings that do not address these fundamental challenges with transparent methods are misleading and should be abandoned. We make some suggestions on how focused and standardized evaluations of excellence could be improved and placed in proper context.

  14. Analytical Methods for Verification and Validation of Adaptive Systems in Safety-Critical Aerospace Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A major challenge of the use of adaptive systems in safety-critical applications is the software life-cycle: requirement engineering through verification and...

  15. Nonlinear Schrodinger elliptic systems involving exponential critical growth in R^2

    Directory of Open Access Journals (Sweden)

    Francisco S. B. Albuquerque Albuquerque

    2014-02-01

    Full Text Available This article concerns the existence and multiplicity of solutions for elliptic systems with weights, and nonlinearities having exponential critical growth. Our approach is based on the Trudinger-Moser inequality and on a minimax theorem.

  16. A Scalable Semantics-Based Verification System for Flight Critical Software Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Modern flight-critical systems include hundreds of thousands to millions of lines of code. The Boeing 777, for instance, includes over 2 million lines of code....

  17. A Scalable Semantics-Based Verification System for Flight Critical Software Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight-critical systems rely on an ever increasing amount of software—the Boe- ing 777 contains over 2 million lines of code. Most of this code is written in...

  18. DOD Major Automated Information Systems: Improvements Can Be Made in Reporting Critical Changes and Clarifying Leadership Responsibility

    Science.gov (United States)

    2016-03-01

    DOD MAJOR AUTOMATED INFORMATION SYSTEMS Improvements Can Be Made in Reporting Critical Changes and Clarifying... INFORMATION SYSTEMS Improvements Can Be Made in Reporting Critical Changes and Clarifying Leadership Responsibility Why GAO Did This Study The National... information system (MAIS) programs that experienced a critical change to program cost, schedule, or system performance targets submitted complete reports to

  19. A mathematical framework for critical transitions: bifurcations, fast-slow systems and stochastic dynamics

    CERN Document Server

    Kuehn, Christian

    2011-01-01

    Bifurcations can cause dynamical systems with slowly varying parameters to transition to far-away attractors. The terms "critical transition" or "tipping point" have been used to describe this situation. Critical transitions have been observed in an astonishingly diverse set of applications from ecosystems and climate change to medicine and finance. The goal of this paper is to bring together a variety of techniques from dynamical systems theory to analyze critical transitions. In particular, we shall focus on identifying indicators for catastrophic shifts in the dynamics. Starting from classical bifurcation theory and incorporating multiple time scale dynamics we are able to give a detailed analysis of local bifurcations that induce critical transitions. We characterize several early warning signs for a transition such as slowing down and bifurcation delay. Then we take into account stochastic effects and proceed to model critical transitions by fast-slow stochastic differential equations. The interplay betw...

  20. Critical properties of the transverse ferromagnetic spin system with random single-ion anisotropy

    Institute of Scientific and Technical Information of China (English)

    邓玲玲; 晏世雷

    2002-01-01

    A transverse ferromagnetic spin-1 system with a random single-ion anisotropy is considered in the framework of an Ising model. The effective field theory and decoupling approximation are applied to the derivation of the expressions of magnetizations for a honeycomb lattice. Special emphasis is placed on the critical properties of the system. New critical properties are obtained in a certain range of single-ion anisotropy, random concentration, and transverse field.We discuss in detail the influence of the random concentration and transverse field on the critical properties. Some phenomena have not been discovered in previous reports. Detailed descriptions of the phase transition and magnetization curves are presented.

  1. Improving IT project governance: A reflective analysis based on critical systems heuristics

    Directory of Open Access Journals (Sweden)

    David Johnstone

    2017-05-01

    Full Text Available IT project governance involves establishing authority structures, policies and mechanisms for IT projects. However, the way governance arrangements are implemented can sometimes exclude or marginalise important stakeholders. In this paper, we use critical systems thinking, and the notions of boundary critique and entrenched structural conflict, to inform a critical re-analysis of a case study where the governance proved relatively ineffective. We use the ‘twelve questions’ from the critical systems heuristics (CSH approach to diagnose problems with governance arrangements and suggest solutions. Based on this, we suggest the CSH approach has theoretical and practical efficacy for improving IT project governance in general.

  2. Application of queueing models to multiprogrammed computer systems operating in a time-critical environment

    Science.gov (United States)

    Eckhardt, D. E., Jr.

    1979-01-01

    A model of a central processor (CPU) which services background applications in the presence of time critical activity is presented. The CPU is viewed as an M/M/1 queueing system subject to periodic interrupts by deterministic, time critical process. The Laplace transform of the distribution of service times for the background applications is developed. The use of state of the art queueing models for studying the background processing capability of time critical computer systems is discussed and the results of a model validation study which support this application of queueing models are presented.

  3. THE UNIQUENESS OF LIMIT CYCLE AND CRITICAL POINT FOR A CLASS OF CUBIC SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,we consider an accompany system concerning some class of cubic system. We then prove that the system has at most one limit cycle. Finally,we obtain the topological structure of both the critical points at infinity and the singular points lying on invariant lines.

  4. Early-warning signals (potentially) reduce uncertainty in forecasted timing of critical shifts in vegetation systems

    NARCIS (Netherlands)

    Karssenberg, D.J.; Bierkens, M.F.P.

    2011-01-01

    Non-linear systems may undergo abrupt transitions as a result of a gradual change in system drivers. Such regime shifts, or critical transitions, have been described for a large range of spatio-temporal systems, including those studied in the social sciences, ecology, geology, and climatology. Regim

  5. Diversity for security: case assessment for FPGA-based safety-critical systems

    Directory of Open Access Journals (Sweden)

    Kharchenko Vyacheslav

    2016-01-01

    Full Text Available Industrial safety critical instrumentation and control systems (I&Cs are facing more with information (in general and cyber, in particular security threats and attacks. The application of programmable logic, first of all, field programmable gate arrays (FPGA in critical systems causes specific safety deficits. Security assessment techniques for such systems are based on heuristic knowledges and the expert judgment. Main challenge is how to take into account features of FPGA technology for safety critical I&Cs including systems in which are applied diversity approach to minimize risks of common cause failure. Such systems are called multi-version (MV systems. The goal of the paper is in description of the technique and tool for case-based security assessment of MV FPGA-based I&Cs.

  6. Critical issues related to transfersomes - novel vesicular system

    Directory of Open Access Journals (Sweden)

    Kombath Ravindran Vinod

    2012-03-01

    Full Text Available It has become increasingly apparent that vesicular drug delivery elicits modest possessions in drug targeting. Transfersomes are a form of elastic or deformable vesicle, which were first introduced in the early 1990s. Elas ticity can be achieved by using an edge activator in the lipid bilayer structure. Molecules greater than 500 Da normally do not cross the skin. This prevents epicutaneous delivery of the high molecular weight therapeutics as well as non-invasive transcutaneous immunisation. Transdermal route will always remain a lucrative area for drug delivery. With the advent of new categories of drugs like peptides this route has captured more focus to combat the problems related to their delivery through oral route. But the transdermal route is equally filled with the hopes and disappointments as the transport of drug through this route faces many problems especially for the large molecules. To answer this problem many approaches were adopted. One of the very recent approaches is the use of ultra-deformable carrier systems (transfersomes. They have been used as drug carriers for a range of small molecules, peptides, proteins and vaccines, both in vitro and in vivo. Transfersomes penetrate through the pores of stratum corneum which are smaller than its size and get into the underlying viable skin in intact form. This is because of its deformable nature. The aim of this article is explanation the formation of micelle and vesicles, various types of vesicles, specifically focusing on transfersomes.

  7. Reconstructing the critically damaged health service system of the country.

    Science.gov (United States)

    Banerji, Debabar

    2012-01-01

    India's ruling class, in association with international agencies, bureaucrats, and business interests, has formed a powerful syndicate that has been imposing its will on the country to the detriment of public health. After gaining independence, India developed a body of knowledge suited to its social, cultural, economic, and epidemiological conditions. This led to an alternative approach to public health education, practice, and research that foreshadowed the Alma Ata Declaration on Primary Health Care of 1978. In the early 1980s, global power shifts undermined national and international commitment to the Declaration. Wealthy countries' response to the declaration of self-reliance by economically disadvantaged countries was swift: an effort to suppress the Declaration's ideals in favor of an unscientific, market-driven agenda. As a result, public health practice in India virtually disappeared. Responding to growing restiveness among a population in need, political leaders have launched the foredoomed National Rural Health Mission and pursued an American brand of public health through the Public Health Foundation of India. Reconstructing the damaged public health system will require pressure on the syndicate to ensure India's public health heritage will be used to effectively transfer "People's health in people's hands" according to the guidelines set down at Alma Ata.

  8. Regionalization in the Brazilian Healthcare System, SUS: a critical review.

    Science.gov (United States)

    Fernandes, Fernando Manuel Bessa

    2017-04-01

    to review the output and the use of the data to support managers in making decisions on the healthcare system, and analyze academic output on the theme. An online search of the SciELO database for articles using 'regionalization' and 'health/healthcare' as the keywords, and all indices as the 'scope of the study'. We found a total of 102 references, and after analyzing the abstracts selected 70 articles that effectively discuss regionalization of health/healthcare in Brazil. We also found four articles in non-health related journals. the institutional criteria (journal, theme area, date of publication, scope and number of authors), and the analytical criteria created by author - Type 1 - "Exploratory Studies" (26), "Evaluation Studies" (6), "Comparison Studies" (3); and "Reports of Experience" (5), Type 2 - "Theoretical-Analytical" papers (20) and "Historical-Conceptual Reviews" (4), and Type 3 - "Editorials (3) and "Book Reviews" (3). regionalization has become more important in journals published since 2010. Most of the articles fall in the Type 1 category.

  9. Potential of Entropic Force in Markov Systems with Nonequilibrium Steady State, Generalized Gibbs Function and Criticality

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Lowell; Qian, Hong

    2016-08-01

    In this paper we revisit the notion of the “minus logarithm of stationary probability” as a generalized potential in nonequilibrium systems and attempt to illustrate its central role in an axiomatic approach to stochastic nonequilibrium thermodynamics of complex systems. It is demonstrated that this quantity arises naturally through both monotonicity results of Markov processes and as the rate function when a stochastic process approaches a detrministic limit. We then undertake a more detailed mathematical analysis of the consequences of this quantity, culminating in a necessary and sufficient condition for the criticality of stochastic systems. This condition is then discussed in the context of recent results about criticality in biological systems.

  10. Synthesis of Communication Schedules for TTEthernet-Based Mixed-Criticality Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul; Steiner, Wilfried

    2012-01-01

    In this paper we are interested in safety-critical distributed systems, composed of heterogeneous processing elements interconnected using the TTEthernet protocol. We address hard real-time mixed-criticality applications, which may have different criticality levels, and we focus on the optimizati......, and the end-to-end delay of the RC traffic is minimized. We have proposed a Tabu Search-based approach to solve this optimization problem. The proposed algorithm has been evaluated using several benchmarks.......In this paper we are interested in safety-critical distributed systems, composed of heterogeneous processing elements interconnected using the TTEthernet protocol. We address hard real-time mixed-criticality applications, which may have different criticality levels, and we focus on the optimization...... allocation for RC messages. Given the set of mixed-criticality messages in the system and the topology of the virtual links on which the messages are transmitted, we are interested to synthesize offline the static schedules for the TT messages, such that the deadlines for the TT and RC messages are satisfied...

  11. SOME CRITICAL ASPECTS CONCERNING THE INSTITUTIONAL SYSTEM OF EUROPEAN UNION

    Directory of Open Access Journals (Sweden)

    Timofte Claudia Simona

    2013-07-01

    Full Text Available In this paper we want to clarify and understand the decisional process in European which is related to the determination of the identity of the Union, answering to several questions concerning the implementation of the European Union into an organization, the different relations with other organizations and with the international law. In the family of the international organizations, the European Union has its own place because it realizes an economic integration project and a political one, a supranational but refusing the traditional categories of constitution and the international law. Qualifying as an international organization sui generis, EU developed a new legal order, deciding to create a supranational organization, formed by Member States and their citizens. The integration process is a permanent challenge opened to a new and developing process for solving all the internal and external problems of the EU. The States have an international "sensitivity" when the application of EU rules exceeds their obligations laid down in the Treaties to third countries and international organizations to which they have not exempted obligations. It was argued that the concept of "demos" or acting people is intrinsically linked to that of the nation-State. The issue of democratic deficit of the European Union is bound to four basic problems: the construction as a whole and therefore of the institutional system, under the principle of conferral, the Union shall act only within the limits that Member States have been conferred in the Treaties to attain the objectives that they set, The Treaty of Lisbon reinforces the legitimacy of the operation of the Union based on free and democratic will expressed by Member States. European construction is achieved through a democratic transfer of competences of the democratic States to a Commission subject to a weak democratic control, while the European Central Bank preserves absolute dominion over its monetary policy

  12. A Macroscopic Description of Self-Organized Criticality Systems and Astrophysical Applications

    CERN Document Server

    Aschwanden, Markus J

    2013-01-01

    We suggest a generalized definition of self-organized criticality (SOC) systems: SOC is a critical state of a nonlinear energy dissipation system that is slowly and continuously driven towards a critical value of a system-wide instability threshold, producing scale-free, fractal-diffusive, and intermittent avalanches with powerlaw-like size distributions. We develop here a macroscopic description of SOC systems that provides an equivalent description of the complex microscopic fine structure, in terms of fractal-diffusive transport (FD-SOC). Quantitative values for the size distributions of SOC parameters (length scales $L$, time scales $T$, fluxes $F$, and energies $E$) are derived from first principles, using the scale-free probability theorem, $N(L) dL \\propto L^{-d}$, for Euclidean space dimension $d$. We apply this model to astrophysical SOC systems, such as lunar craters, the asteroid belt, Saturn ring particles, magnetospheric substorms, radiation belt electrons, solar flares, stellar flares, pulsar gl...

  13. A universal indicator of critical state transitions in noisy complex networked systems.

    Science.gov (United States)

    Liang, Junhao; Hu, Yanqing; Chen, Guanrong; Zhou, Tianshou

    2017-02-23

    Critical transition, a phenomenon that a system shifts suddenly from one state to another, occurs in many real-world complex networks. We propose an analytical framework for exactly predicting the critical transition in a complex networked system subjected to noise effects. Our prediction is based on the characteristic return time of a simple one-dimensional system derived from the original higher-dimensional system. This characteristic time, which can be easily calculated using network data, allows us to systematically separate the respective roles of dynamics, noise and topology of the underlying networked system. We find that the noise can either prevent or enhance critical transitions, playing a key role in compensating the network structural defect which suffers from either internal failures or environmental changes, or both. Our analysis of realistic or artificial examples reveals that the characteristic return time is an effective indicator for forecasting the sudden deterioration of complex networks.

  14. On power system blackout modeling and analysis based on self-organized criticality

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly,a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description,which serves as a concrete example of the proposed generalized SOC,are given. Secondly,five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally,this paper analyzes SOC in power systems,such as,the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system,and cas-cading failures process.

  15. On power system blackout modeling and analysis based on self-organized criticality

    Institute of Scientific and Technical Information of China (English)

    MEI ShengWei; XUE AnCheng; ZHANG XueMin

    2008-01-01

    This paper makes a comprehensive survey on power system blackout modeling and analysis based on SOC (self-organized criticality). Firstly, a generalized SOC theory from the viewpoint of cybernetics is introduced. Then the evolution model of power system and its relative mathematical description, which serves as a concrete example of the proposed generalized SOC, are given. Secondly, five blackout models capturing various critical properties of power systems in different time-scales are listed. Finally, this paper analyzes SOC in power systems, such as, the revelation of criticalities of proposed models in both micro-scale and macro-scale which can be used to assess the security of power system, and cascading failures process.

  16. Stability analysis of closed-loop super-critical pressure systems

    Science.gov (United States)

    Smith, Walter Castro

    The current study investigates the mechanisms governing flow induced stability of super-critical pressure fluid systems. Super-critical pressure fluid systems have been investigated as a mechanism for heat extraction from power systems for over a century. There are numerous benefits to these systems, but also potential pitfalls which must be examined. While super-critical pressure systems do not undergo phase change, they may be subject to the same flow induced instabilities which affect and limit two-phase systems. The objective of the current study is to develop a modeling and analysis framework to evaluate and understand flow-induced instabilities in super-critical pressure systems. The developed framework is used to evaluate experimental systems which have been constructed and tested by other investigators. The developed model shows good comparison with both the steady state and transient results published by other researchers. The model has been used to predict instabilities in experimental systems, as well as to show how some systems are more susceptible to instability than others. Stability maps have been constructed in a similar manner to those published for single heated flow path analysis.

  17. Critical Success Factors for Enterprise Resource Planning System Implementation: A Case Study in Malaysian SME

    Directory of Open Access Journals (Sweden)

    Feybi Ariani Goni

    2011-01-01

    Full Text Available Implementing Enterprise Resource Planning (ERP system for Malaysian Small to Medium Enterprises (SMEs is not just a technological challenge. It is a socio-technological endeavour which mandates modifying existing applications and redesigning business processes to facilitate ERP system implementation. Most Malaysian SMEs cannot afford to adopt an existing ERP system due to the extremely high cost and complex implementation. The ERP system implementation literature contains many case studies of organizations that have implemented ERP system successfully. However, many Malaysian SMEs do not achieve success in their ERP system implementation. There are very few studies have represented and developed critical success factors of ERP system implementation projects highlighted for SMEs. This research seeks to explore the critical success factors for successful ERP system implementation in Malaysian SMEs. The research method is based on a case study within Malaysian SME to perform a critical success factors model of ERP system implementation adoption which has validated by a number of SMEs in Malaysia. The proposed model will help outline the critical factors that should be considered by Malaysian SMEs in uccessfully adopting ERP system.

  18. Estimation of the critical behavior in an active colloidal system with Vicsek-like interactions

    Science.gov (United States)

    Trefz, Benjamin; Siebert, Jonathan Tammo; Speck, Thomas; Binder, Kurt; Virnau, Peter

    2017-02-01

    We study numerically the critical behavior of a modified, active Asakura-Oosawa model for colloid-polymer mixtures. The colloids are modeled as self-propelled particles with Vicsek-like interactions. This system undergoes phase separation between a colloid-rich and a polymer-rich phase, whereby the phase diagram depends on the strength of the Vicsek-like interactions. Employing a subsystem-block-density distribution analysis, we determine the critical point and make an attempt to estimate the critical exponents. In contrast to the passive model, we find that the critical point is not located on the rectilinear diameter. A first estimate of the critical exponents β and ν is consistent with the underlying 3d-Ising universality class observed for the passive model.

  19. Use of virtual reality gaming systems for children who are critically ill.

    Science.gov (United States)

    Salem, Yasser; Elokda, Ahmed

    2014-01-01

    Children who are critically ill are frequently viewed as "too sick" to tolerate physical activity. As a result, these children often fail to develop strength or cardiovascular endurance as compared to typically developing children. Previous reports have shown that early participation in physical activity in is safe and feasible for patients who are critically ill and may result in a shorter length of stay and improved functional outcomes. The use of the virtual reality gaming systems has become a popular form of therapy for children with disabilities and has been supported by a growing body of evidence substantiating its effectiveness with this population. The use of the virtual reality gaming systems in pediatric rehabilitation provides the children with opportunity to participate in an exercise program that is fun, enjoyable, playful, and at the same time beneficial. The integration of those systems in rehabilitation of children who are critically ill is appealing and has the potential to offer the possibility of enhancing physical activities. The lack of training studies involving children who are critically ill makes it difficult to set guidelines on the recommended physical activities and virtual reality gaming systems that is needed to confer health benefits. Several considerations should be taken into account before recommended virtual reality gaming systems as a training program for children who are critically ill. This article highlighted guidelines, limitations and challenges that need to be considered when designing exercise program using virtual reality gaming systems for critically ill children. This information is helpful given the popular use of virtual reality gaming systems in rehabilitation, particularly in children who are critically ill.

  20. Bibliography for nuclear criticality accident experience, alarm systems, and emergency management

    Energy Technology Data Exchange (ETDEWEB)

    Putman, V.L.

    1995-09-01

    The characteristics, detection, and emergency management of nuclear criticality accidents outside reactors has been an important component of criticality safety for as long as the need for this specialized safety discipline has been recognized. The general interest and importance of such topics receives special emphasis because of the potentially lethal, albeit highly localized, effects of criticality accidents and because of heightened public and regulatory concerns for any undesirable event in nuclear and radiological fields. This bibliography lists references which are potentially applicable to or interesting for criticality alarm, detection, and warning systems; criticality accident emergency management; and their associated programs. The lists are annotated to assist bibliography users in identifying applicable: industry and regulatory guidance and requirements, with historical development information and comments; criticality accident characteristics, consequences, experiences, and responses; hazard-, risk-, or safety-analysis criteria; CAS design and qualification criteria; CAS calibration, maintenance, repair, and testing criteria; experiences of CAS designers and maintainers; criticality accident emergency management (planning, preparedness, response, and recovery) requirements and guidance; criticality accident emergency management experience, plans, and techniques; methods and tools for analysis; and additional bibliographies.

  1. Is the critical point for aperture crossing adapted to the person-plus-object system?

    Science.gov (United States)

    Hackney, Amy L; Cinelli, Michael E; Frank, Jim S

    2014-01-01

    When passing through apertures, individuals scale their actions to their shoulder width and rotate their shoulders or avoid apertures that are deemed too small for straight passage. Carrying objects wider than the body produces a person-plus-object system that individuals must account for in order to pass through apertures safely. The present study aimed to determine whether individuals scale their critical point to the widest horizontal dimension (shoulder or object width). Two responses emerged: Fast adapters adapted to the person-plus-object system by maintaining a consistent critical point regardless of whether the object was carried while slow adapters initially increased their critical point (overestimated) before adapting back to their original critical point. The results suggest that individuals can account for increases in body width by scaling actions to the size of the object width but people adapt at different rates.

  2. Improved Reliability Memory’s Module Structure for Critical Application Systems

    Directory of Open Access Journals (Sweden)

    Ryabtsev V.G

    2016-01-01

    Full Text Available For critical application systems, which control nuclear power plants and other energy facilities, air, sea and ground vehicles, the needs to ensure their operability are increased. To fulfill this requirement, it is necessary to increase the technical readiness coefficient, the value of which increases with decreasing recovery time control system in case of fault of its constituent units. The main control system components critical applications are memory devices, which store programs and used for performing algorithms control. Semiconductor memory modules with automatic recovery functionality at multiple faults can be used in systems of critical applications protection and management where the use of fault-tolerant digital devices is a necessity due to the inability of traditional methods of repair by replacing the failed elements.

  3. The critical role of the endocannabinoid system in emotional homeostasis: avoiding excess and deficiencies.

    Science.gov (United States)

    Marco, E M; Viveros, M P

    2009-10-01

    The endocannabinoid system is critical in the regulation of emotion and stress responsiveness. Despite the promising therapeutic value of its pharmacological modulation, deficient and excessive endocannabinoid signalling should be avoided. This mini-review will provide an up-to-date revision on this topic, emphasizing the relevance of a normative endocannabinoid system for emotional homeostasis.

  4. Weak Centers and Local Bifurcations of Critical Periods at Infinity for a Class of Rational Systems

    Institute of Scientific and Technical Information of China (English)

    Wen-tao HUANG; Valery G. ROMANOVSKI; WEI-NIAN ZHANG

    2013-01-01

    We describe an approach to studying the center problem and local bifurcations of critical periods at infinity for a class of differential systems.We then solve the problem and investigate the bifurcations for a class of rational differential systems with a cubic polynomial as its numerator.

  5. Network attack detection and defense: securing industrial control systems for critical infrastructures (Dagstuhl Seminar 14292)

    NARCIS (Netherlands)

    Dacer, Marc; Kargl, Frank; König, Hartmut; Valdes, Alfonso

    2014-01-01

    This report documents the program and the outcomes of Dagstuhl Seminar 14292 “Network Attack Detection and Defense: Securing Industrial Control Systems for Critical Infrastructures”. The main objective of the seminar was to discuss new approaches and ideas for securing industrial control systems. It

  6. Positive and ground state solutions for the critical Klein-Gordon-Maxwell system with potentials

    CERN Document Server

    Carriao, Paulo C; Miyagaki, Olimpio H

    2010-01-01

    In this paper we study a class of Klein-Gordon-Maxwell system when the nonlinearity exhibits critical growth. First we prove both existence and ground state solutions for this system with a periodic potencial V, and then we show the existence in the case that a nonperiodic potencial V is introduced.

  7. Determination of Critical Parameters of Carbon Dioxide+ Butyraldehyde System with Different Compositions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-chang; GAO Xi-xin; CAO Wei-liang

    2005-01-01

    Supercritical carbon dioxide( SC-CO2 ) is considered in green chemistry as a substitute for conventional solvents in chemical reactions due to its environmentally benign character. Recently we have reported the homogeneous hydroformylation of propylene in supercritical carbon dioxide( SC-CO2 ), which is an example of this kind of application of carbon dioxide. The determination for the critical parameters of carbon dioxide + butyraldehyde mixtures is necessary for this reaction design which is the focus of the present paper. The critical parameters of the binary systems were determined via the static visual method at a constant volume with the molar fraction of butyraldehyde ranging from 1.0%to 2. 2% and the pressure ranging from 5 to 10 MPa. The experimental results show that the critical pressure and temperature increased with increasing the molar fraction of butyraldehyde. The bubble(dew) temperatures and the bubble (dew) pressures for the binary systems were also determined experimentally. The p-T Figures at different compositions of the binary systems were described. In addition, the critical compressibility factors Zc of the binary systems at different concentrations of n-butyraldehyde were calculated. It was found that the critical compressibility factor values of the binary systems decreased with increasing the molar fraction of n-butyraldehyde in the experimental range.

  8. Black Hole Type Quantum Computing in Critical Bose-Einstein Systems

    CERN Document Server

    Dvali, Gia

    2015-01-01

    Recent ideas about understanding physics of black hole information-processing in terms of quantum criticality allow us to implement black hole mechanisms of quantum computing within critical Bose-Einstein systems. The generic feature, uncovered both by analytic and numeric studies, is the emergence at the critical point of gapless weakly-interacting modes, which act as qubits for information-storage at a very low energy cost. These modes can be effectively described in terms of either Bogoliubov or Goldstone degrees of freedom. The ground-state at the critical point is maximally entangled and far from being classical. We confirm this near-critical behavior by a new analytic method. We compute growth of entanglement and show its consistency with black hole type behavior. On the other hand, in the over-critical regime the system develops a Lyapunov exponent and scrambles quantum information very fast. By, manipulating the system parameters externally, we can put it in and out of various regimes and in this way ...

  9. A software cost model with maintenance and risk costs for safety-critical systems

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-wei; YANG Xiao-zong; QU Feng; DONG Jian

    2006-01-01

    According to the consequences of software failures, software faults remaining in safety-critical systems can be classified into two sets: common faults and fatal faults. Common faults cause slight loss when they are activated. A fatal fault can lead to significant loss, and even damage the safety-critical system entirely when it is activated. A software reliability growth model for safety-critical systems is developed based on G-O model. And a software cost model is proposed too. The cost model considers maintenance and risk costs due to software failures. The optimal release policies are discussed to minimize the total software cost. A numerical example is provided to illustrate how to use the results we obtained.

  10. Efficient schedulability analysis for mixed-criticality systems under deadline-based scheduling

    Directory of Open Access Journals (Sweden)

    Chen Yao

    2014-08-01

    Full Text Available Safety-critical avionics systems which become more complex and tend to integrate multiple functionalities with different levels of criticality for better cost and power efficiency are subject to certifications at various levels of rigorousness. In order to simultaneously guarantee temporal constraints at all different levels of assurance mandated by different criticalities, novel scheduling techniques are in need. In this paper, a mixed-criticality sporadic task model with multiple virtual deadlines is built and a certification-cognizant dynamic scheduling approach referred as earliest virtual-deadline first with mixed-criticality (EVDF-MC is considered, which exploits different relative deadlines of tasks in different criticality modes. As for the corresponding schedulability analysis problem, a sufficient and efficient schedulability test is proposed on the basis of demand-bound functions derived in the mixed-criticality scenario. In addition, a modified simulated annealing (MSA-based heuristic approach is established for virtual deadlines assignment. Experiments performing simulations with randomly generated tasks indicate that the proposed approach is computationally efficient and competes well against the existing approaches.

  11. Efficient schedulability analysis for mixed-criticality systems under deadline-based scheduling

    Institute of Scientific and Technical Information of China (English)

    Chen Yao; Li Qiao; Li Zheng; Xiong Huagang

    2014-01-01

    Safety-critical avionics systems which become more complex and tend to integrate multiple functionalities with different levels of criticality for better cost and power efficiency are subject to certifications at various levels of rigorousness. In order to simultaneously guarantee tem-poral constraints at all different levels of assurance mandated by different criticalities, novel sched-uling techniques are in need. In this paper, a mixed-criticality sporadic task model with multiple virtual deadlines is built and a certification-cognizant dynamic scheduling approach referred as ear-liest virtual-deadline first with mixed-criticality (EVDF-MC) is considered, which exploits different relative deadlines of tasks in different criticality modes. As for the corresponding schedulability analysis problem, a sufficient and efficient schedulability test is proposed on the basis of demand-bound functions derived in the mixed-criticality scenario. In addition, a modified simulated annealing (MSA)-based heuristic approach is established for virtual deadlines assignment. Experi-ments performing simulations with randomly generated tasks indicate that the proposed approach is computationally efficient and competes well against the existing approaches.

  12. Developing a PQ monitoring system for assessing power quality and critical areas detection

    Directory of Open Access Journals (Sweden)

    Miguel Romero

    2011-10-01

    Full Text Available This paper outlines the development of a power quality monitoring system. The system is aimed at assessing power quality and detecting critical areas throughout at distribution system. Such system integrates a hardware system and a software processing tool developed in four main stages. Power quality disturbances are registered by PQ meters and the data is transmitted through a 3G wireless network. This data is processed and filtered in an open source database. Some interesting statistical indices related to voltage sags, swells, flicker and voltage unbalance are obtained. The last stage displays the indices geo-referenced on power quality maps, allowing the identification of critical areas according to different criteria. The results can be analyzed using clustering tools to identify differentiated quality groups in a city. The proposed system is an open source tool useful to electricity utilities to analyze and manage large amount of data.

  13. Analysis of Highly Wind Power Integrated Power System model performance during Critical Weather conditions

    DEFF Research Database (Denmark)

    Basit, Abdul; Hansen, Anca Daniela; Sørensen, Poul Ejnar

    2014-01-01

    . For this purpose, the power system model has been developed that represents the relevant dynamic features of power plants and compensates for power imbalances caused by the forecasting error during critical weather conditions. The regulating power plan, as an input time series for the developed power system model......Secure power system operation of a highly wind power integrated power system is always at risk during critical weather conditions, e.g. in extreme high winds. The risk is even higher when 50% of the total electricity consumption has to be supplied by wind power, as the case for the future Danish...... power system in 2020. This paper analyses and compares the performance of the future Danish power system during extreme wind speeds, where wind power plants are either controlled through a traditional High Wind Shut Down storm controller or a new High Wind Extended Production storm controller...

  14. A Methodological Framework for Software Safety in Safety Critical Computer Systems

    Directory of Open Access Journals (Sweden)

    P. V. Srinivas Acharyulu

    2012-01-01

    Full Text Available Software safety must deal with the principles of safety management, safety engineering and software engineering for developing safety-critical computer systems, with the target of making the system safe, risk-free and fail-safe in addition to provide a clarified differentaition for assessing and evaluating the risk, with the principles of software risk management. Problem statement: Prevailing software quality models, standards were not subsisting in adequately addressing the software safety issues for real-time safety-critical embedded systems. At present no standard framework does exist addressing the safety management and safety engineering priniciples for the development of software safety in safety-critical computer systems. Approach: In this study we propose a methodological framework involving safety management practices, safety engineering practices and software development life cycle phases for the development of software safety. In this framework we make use of the safety management practices such as planning, defining priniciples, fixing responsibilities, creteria and targets, risk assessment, design for safety, formulating safety requirements and integrating skills and techniques to address safety issues early with a vision for assurance and so on. In this framework we have also analysed integration of applicability of generic industrial heirarchy and software development heirarchy, with derived cyclical review involving safety professionals generating a nodal point for software safety. Results: This framework is applied to safety-critical software based laboratory prototype Railroad Crossing Control System (RCCS with a limited complexity. The results have shown that all critical operations were safe and risk free. Conclusion: The development of software based on the proposed framework for RCCS have shown a clarified and improved safety-critical operations of the overall system peformance.

  15. Critical success factors for the implementation of information system: a study case from the perspective of a systems integrator firm

    OpenAIRE

    Eduardo Belmonte Möller; Alejandro Germán Frank; Marcelo Nogueira Cortimiglia

    2014-01-01

    Implementation is one of the critical phases for information systems (IS) success. There are several criteria that define IS implementation success. There are also several critical success factors (CSF) that influence overall IS success. These criteria and success factors are usually studied in a dispersed way in academic literature. So, there is a need for a deeper understanding of success criteria and CSF, especially during the implementation phase. Therefore, this paper aims to define whic...

  16. Critical slowing down of the Gaussian spin system on diamond—type hierarchical lattices

    Institute of Scientific and Technical Information of China (English)

    朱建阳; 朱涵

    2003-01-01

    Based on the single-spin transition critical dynamics,we have investigated the critical slowing down of the Gaussian spin model situated on the fractal family of diamond-type hierarchical lattices.We calculate the dynamical critical exponent z and the correlation-length critical exponent v using the dynamical decimation renormalization-group technique.The result,together with some earlier ones,suggests us to conclude that on a wide range of geometries,zv=1 is the general relationship,while the two exponents depend on the specific structure,However,we have investigated for various lattices in an earlier paper,the system studied in this paper shows highly universal z=1/v=2 independent of the structure and the dimensionality.

  17. Critical slowing down of the Gaussian spin system on diamond-type hierarchical lattices

    Institute of Scientific and Technical Information of China (English)

    朱建阳; 朱涵

    2003-01-01

    Based on the single-spin transition critical dynamics, we have investigated the critical slowing down of the Gaussian spin model situated on the fractal family of diamond-type hierarchical lattices. We calculate the dynamical critical exponent z and the correlation-length critical exponent v using the dynamical decimation renormalization-group technique. The result, together with some earlier ones, suggests us to conclude that on a wide range of geometries, zv = 1is the general relationship, while the two exponents depend on the specific structure. However, we have investigated for various lattices in an earlier paper, the system studied in this paper shows highly universal z = 1/v = 2 independent of the structure and the dimensionality.

  18. Microscopic structure and gas-gas critical line of the Ar-water system

    Energy Technology Data Exchange (ETDEWEB)

    Ricci, M.A. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi ' Roma Tre' , Via della Vasca Navale 84, 00146 Rome (Italy)]. E-mail: riccim@fis.uniroma3.it; Mancinelli, R. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi ' Roma Tre' , Via della Vasca Navale 84, 00146 Rome (Italy); Lu Russo, M. [ESRF, European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble (France); Botti, A. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi ' Roma Tre' , Via della Vasca Navale 84, 00146 Rome (Italy); Bruni, F. [Dipartimento di Fisica ' E. Amaldi' , Universita degli Studi ' Roma Tre' , Via della Vasca Navale 84, 00146 Rome (Italy); Soper, A.K. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

    2006-11-15

    The dependence of the derivative of the gas-gas critical temperature on the microscopic structure of a mixture is analyzed using neutron diffraction on the Ar-water system at two solute concentrations. At low Ar concentration the critical line departs from the critical point of the solvent with negative derivative: at a microscopic level this corresponds to a repulsive solute-solvent interaction, keeping Ar atoms outside the first water-water neighboring shell. As the solute concentration increases at constant temperature and pressure, the critical temperature goes through a minimum and eventually Ar atoms enter the first neighbor water shell. At this point, no H-bonding between water molecules is visible.

  19. Qualitative Analysis of Critical Transitions in Complex Disease Propagation from a Dynamical Systems Perspective

    Science.gov (United States)

    Wang, Gang; Zou, Xiufen

    2016-12-01

    Considerable evidence suggests that in complex diseases the deteriorations are often abrupt, and can be viewed as a bifurcation or a critical transition from one asymptotically stable equilibrium to another one at a tipping point. Here, we propose some new ideas to detect early-warning signals of such critical transitions from the perspective of qualitative theory of ordinary differential equations. Specifically, we theoretically derive three indicators that serve as a general early-warning signal indicating an imminent bifurcation or sudden deterioration before the critical transition occurs. Then, we verify our theoretical results by numerical simulations for three examples. Our work forms a starting point to motivate new mathematical insights into predictability for critical transitions of dynamical systems from a new perspective.

  20. Coal gasification systems engineering and analysis. Appendix F: Critical technology items/issues

    Science.gov (United States)

    1980-01-01

    Critical technology items and issues are defined in which there is a need for developmental research in order to assure technical and economic success for the state of the art of coal gasification in the United States. Technology development needs for the main processing units and the supporting units are discussed. While development needs are shown for a large number of systems, the most critical areas are associated with the gasifier itself and those systems which either feed the gasifier or directly receive products form the gasifier.

  1. Variation of critical point of aging transition in a networked oscillators system.

    Science.gov (United States)

    Huang, Wenwen; Zhang, Xiyun; Hu, Xin; Zou, Yong; Liu, Zonghua; Guan, Shuguang

    2014-06-01

    In this work, we study the variation of critical point in aging transition in a networked system consisting of both active and inactive oscillators. By theoretical analysis and numerical simulations, we show that the critical point of aging transition actually is determined by the (normalized) cross links between active and inactive subpopulations of oscillators. This reveals how specific configuration of active and inactive oscillators in the network can lead to the variation of transition point. In particular, we investigate how different strategies of targeted inactivation influence the transition point based on the theory. Our results theoretically explain why the low-degree nodes are crucial regarding dynamical robustness in such systems.

  2. Critical Thinking: A Missing Ingredient in DoD’s Acquisition (Education) System

    Science.gov (United States)

    2014-10-01

    ability to mentor their teams on sound critical, creative and analytical thinking techniques. Many of these changes counter DAU’s cost-per-training... Thinking : A Missing Ingredient in DoD’s Acquisition (Education) System 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...Rev. 8-98) Prescribed by ANSI Std Z39-18 Critical Thinking A Missing Ingredient in DoD’s Acquisition (Education) System Sean M. Frisbee n Scott

  3. Critical Behaviors and Finite-Size Scaling of Principal Fluctuation Modes in Complex Systems

    Science.gov (United States)

    Li, Xiao-Teng; Chen, Xiao-Song

    2016-09-01

    Complex systems consisting of N agents can be investigated from the aspect of principal fluctuation modes of agents. From the correlations between agents, an N × N correlation matrix C can be obtained. The principal fluctuation modes are defined by the eigenvectors of C. Near the critical point of a complex system, we anticipate that the principal fluctuation modes have the critical behaviors similar to that of the susceptibity. With the Ising model on a two-dimensional square lattice as an example, the critical behaviors of principal fluctuation modes have been studied. The eigenvalues of the first 9 principal fluctuation modes have been invesitigated. Our Monte Carlo data demonstrate that these eigenvalues of the system with size L and the reduced temperature t follow a finite-size scaling form λn (L, t) = Lγ/ν fn(tL1/ν), where γ is critical exponent of susceptibility and ν is the critical exponent of the correlation length. Using eigenvalues λ1, λ2 and λ6, we get the finite-size scaling form of the second moment correlation length ξ (L, t) &equals L\\tilde ξ (tL1/ν ). It is shown that the second moment correlation length in the two-dimensional square lattice is anisotropic. Supported by the National Natural Science Foundation of China under Grant Nos. 11121403 and 11504384

  4. Critical Task Re-assignment under Hybrid Scheduling Approach in Multiprocessor Real-Time Systems

    CERN Document Server

    Nair, Gopalakrishnan T R

    2012-01-01

    Embedded hard real time systems require substantial amount of emergency processing power for the management of large scale systems like a nuclear power plant under the threat of an earth quake or a future transport systems under a peril. In order to meet a fully coordinated supervisory control of multiple domains of a large scale system, it requires the scenario of engaging multiprocessor real time design. There are various types of scheduling schemes existing for meeting the critical task assignment in multiple processor environments and it requires the tracking of faulty conditions of the subsystem to avoid system underperformance from failure patterns. Hybrid scheduling usually engages a combined scheduling philosophy comprising of a static scheduling of a set of tasks and a highly pre-emptive scheduling for another set of tasks in different situations of process control. There are instances where highly critical tasks need to be introduced at a least expected catastrophe and it cannot be ensured to meet a...

  5. Critical Nodes Identification of Power Systems Based on Controllability of Complex Networks

    Directory of Open Access Journals (Sweden)

    Yu-Shuai Li

    2015-09-01

    Full Text Available This paper proposes a new method for assessing the vulnerability of power systems based on the controllability theories of complex networks. A novel controllability index is established, taking into consideration the full controllability of the power systems, for identifying critical nodes. The network controllability model is used to calculate the minimum number of driver nodes (ND, which can solve the computable problems of the controllability of power systems. The proposed approach firstly applies the network controllability theories to research the power systems' vulnerability, which can not only effectively reveal the important nodes but also maintain full control of the power systems. Meanwhile, the method can also overcome the limitation of the hypothesis that the weight of each link or transmission line must be known compared with the existing literature. In addition, the power system is considered as a directed network and the power system model is also redefined. The proposed methodology is then used to identify critical nodes of the IEEE 118 and 300 bus system. The results show that the failure of the critical nodes can clearly increase ND and lead a significant driver node shift. Thus, the rationality and validity are verified.

  6. High-confidence software for safety-critical process-control systems

    Energy Technology Data Exchange (ETDEWEB)

    Bastani, F.B. [Univ. of Houston, TX (United States)

    1997-12-01

    Software for safety-critical systems, such as nuclear power plant control systems; avionic systems; and medical, defense, and manufacturing systems, must be highly reliable because failures can have catastrophic consequences. While existing methods, such as formal techniques, testing, and fault-tolerant software, can significantly enhance software reliability, they have some limitations in achieving ultrahigh reliability requirements. Formal methods are not able to cope with specification faults, testing is not cost-effective for high-assurance systems, and fault-tolerant software based on diverse designs is susceptible to common-mode failures.

  7. Masters Thesis- Criticality Alarm System Design Guide with Accompanying Alarm System Development for the Radioisotope Production Laboratory in Richland, Washington

    Energy Technology Data Exchange (ETDEWEB)

    Greenfield, Bryce A. [Univ. of New Mexico, Albuquerque, NM (United States)

    2009-12-01

    A detailed instructional manual was created to guide criticality safety engineers through the process of designing a criticality alarm system (CAS) for Department of Energy (DOE) hazard class 1 and 2 facilities. Regulatory and technical requirements were both addressed. A list of design tasks and technical subtasks are thoroughly analyzed to provide concise direction for how to complete the analysis. An example of the application of the design methodology, the Criticality Alarm System developed for the Radioisotope Production Laboratory (RPL) of Richland, Washington is also included. The analysis for RPL utilizes the Monte Carlo code MCNP5 for establishing detector coverage in the facility. Significant improvements to the existing CAS were made that increase the reliability, transparency, and coverage of the system.

  8. Cooperation, competition and the emergence of criticality in communities of adaptive systems

    Science.gov (United States)

    Hidalgo, Jorge; Grilli, Jacopo; Suweis, Samir; Maritan, Amos; Muñoz, Miguel A.

    2016-03-01

    The hypothesis that living systems can benefit from operating at the vicinity of critical points has gained momentum in recent years. Criticality may confer an optimal balance between too ordered and exceedingly noisy states. Here we present a model, based on information theory and statistical mechanics, illustrating how and why a community of agents aimed at understanding and communicating with each other converges to a globally coherent state in which all individuals are close to an internal critical state, i.e. at the borderline between order and disorder. We study—both analytically and computationally—the circumstances under which criticality is the best possible outcome of the dynamical process, confirming the convergence to critical points under very generic conditions. Finally, we analyze the effect of cooperation (agents trying to enhance not only their fitness, but also that of other individuals) and competition (agents trying to improve their own fitness and to diminish those of competitors) within our setting. The conclusion is that, while competition fosters criticality, cooperation hinders it and can lead to more ordered or more disordered consensual outcomes.

  9. Criticality safety validation: Simple geometry, single unit {sup 233}U systems

    Energy Technology Data Exchange (ETDEWEB)

    Putman, V.L.

    1997-06-01

    Typically used LMITCO criticality safety computational methods are evaluated for suitability when applied to INEEL {sup 233}U systems which reasonably can be modeled as simple-geometry, single-unit systems. Sixty-seven critical experiments of uranium highly enriched in {sup 233}U, including 57 aqueous solution, thermal-energy systems and 10 metal, fast-energy systems, were modeled. These experiments include 41 cylindrical and 26 spherical cores, and 41 reflected and 26 unreflected systems. No experiments were found for intermediate-neutron-energy ranges, or with interstitial non-hydrogenous materials typical of waste systems, mixed {sup 233}U and plutonium, or reflectors such as steel, lead, or concrete. No simple geometry experiments were found with cubic or annular cores, or approximating infinite sea systems. Calculations were performed with various tools and methodologies. Nine cross-section libraries, based on ENDF/B-IV, -V, or -VI.2, or on Hansen-Roach source data, were used with cross-section processing methods of MCNP or SCALE. The k{sub eff} calculations were performed with neutral-particle transport and Monte Carlo methods of criticality codes DANT, MCNP 4A, and KENO Va.

  10. Complexity and Self-Organized Criticality of Solid Earth System(Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The author puts forward the proposition of "Complexity and Self-Organized Criticality of Solid Earth System" in the light of: (1) the science of complexity studies the mechanisms of emergence of complexity and is the science of the 21st century, (2) the study of complexity of the earth system would be one of the growing points occupying a strategic position in the development of geosciences in the 21st century. By the proposition we try to cogitate from a new viewpoint the ancient yet ever-new solid earth system. The author abstracts the fundamental problem of the solid earth system from the essence of the generalized geological systems and processes which reads: "the complexity and self-organized criticality of the global nature, structure and dynamical behavior of the whole solid earth system emerging from the multiple coupling and superposition of non-linear interactions among the multicomponents of the earths material and the multiple generalized geological (geological, geophysical, and geochemical) processes". Starting from this cognizance the author proposes eight major themes and the methodology of researches on the complexity and self-organized criticality of the solid earth system.

  11. Complexity and Self-Organized Criticality of Solid Earth System(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The author puts forward the proposition of "Complexity and Self-Organized Criticality of Solid Earth System" in the light of: (1) the science of complexity studies the mechanisms of emergence of complexity and is the science of the 21st century, (2) the study of complexity of the earth system would be one of the growing points occupying a strategic position in the development of geosciences in the 21st century. By the proposition we try to cogitate from a new viewpoint the ancient yet ever-new solid earth system. The author abstracts the fundamental problem of the solid earth system from the essence of the generalized geological systems and processes which reads: "the complexity and self-organized criticality of the global nature, structure and dynamical behavior of the whole solid earth system emerging from the multiple coupling and superposition of non-linear interactions among the multicomponents of the earths material and the multiple generalized geological (geological, geophysical, and geochemical) processes". Starting from this cognizance, the author proposes eight major themes and the methodology of researches on the complexity and self-organized criticality of the solid earth system.

  12. Critical exponents in the transition to chaos in one-dimensional discrete systems

    Indian Academy of Sciences (India)

    G Ambika; N V Sujatha

    2002-07-01

    We report the numerically evaluated critical exponents associated with the scaling of generalized fractal dimensions during the transition from order to chaos. The analysis is carried out in detail in the context of unimodal and bimodal maps representing typical one-dimensional discrete dynamical systems. The behavior of Lyapunov exponents (LE) in the cross over region is also studied for a complete characterization.

  13. Ecopedagogy: A Movement between Critical Dialogue and Complexity: Proposal for a Categories System

    Science.gov (United States)

    Norat, María de los Ángeles Vilches; Herrería, Alfonso Fernández; Rodríguez, Francisco Miguel Martínez

    2016-01-01

    This qualitative research has been undertaken with the purpose of developing an integrated system of categories based on ecopedagogy. Founded on the critical pedagogy of Paulo Freire, this movement moves towards complex thinking and holism. Its theoretical bases are set on principles of sustainability, biosensibility, ethics of care and global…

  14. Critical success factors for implementing supply chain information systems : insights from the pork industry

    NARCIS (Netherlands)

    Denolf, J.M.

    2014-01-01

    Critical success factors for implementing supply chain information systems – Janne M. Denolf Due to intensified competition, companies realize that they should closely collaborate with their supply-chain partners to further cut costs and stay competitive. To do so,

  15. A Study on Critical Thinking Assessment System of College English Writing

    Science.gov (United States)

    Dong, Tian; Yue, Lu

    2015-01-01

    This research attempts to discuss the validity of introducing the evaluation of students' critical thinking skills (CTS) into the assessment system of college English writing through an empirical study. In this paper, 30 College English Test Band 4 (CET-4) writing samples were collected and analyzed. Students' CTS and the final scores of collected…

  16. Students' Learning Behavior, Motivation and Critical Thinking in Learning Management Systems

    Science.gov (United States)

    Wichadee, Saovapa

    2014-01-01

    Computer mediated communication (CMC) offers new opportunities for learners to create communities of inquiry that allow for more active learning. This paper reports on the use of a Learning Management System (LMS) as a tool to facilitate students' writing and critical thinking skills. The primary data for the study came from students'…

  17. A Critical Analysis of Active Learning and an Alternative Pedagogical Framework for Introductory Information Systems Courses

    Science.gov (United States)

    Drake, John R.

    2012-01-01

    Active learning has been championed in academic circles as the pedagogical fix to boring lectures typically found in introduction to information systems courses. However, the literature on active learning is mixed. In this paper, we critically examine active learning research and discover a misplaced emphasis leading to paradoxical findings in…

  18. SLSF loop handling system. Volume III. AISC code evaluations and analysis of critical attachments. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, H.; Cowie, A.; Malek, R. A.; Rafer, A.; Ma, D.; Tebo, F.

    1978-10-01

    SLSF loop handling system was analyzed for deadweight and postulated dynamic loading conditions using a linear elastic static equivalent method of stress analysis. Stress computations of Cradle and critical attachments per AISC Code guidelines are presented. HFEF is credited with in-depth review of initial phase of work.

  19. Exploration and Visualization: Making Critical Connections about Linear Systems of Equations.

    Science.gov (United States)

    Smith, Karan B.

    1997-01-01

    Presents activities to demonstrate that current technology allows readily accessible representations in algebraic, numeric, and geometric forms. Argues that integrating these different representations into the curriculum helps students to think more critically about systems. Discusses problem solving using multiple representations, equivalent…

  20. Critical success factors for implementing supply chain information systems : insights from the pork industry

    NARCIS (Netherlands)

    Denolf, J.M.

    2014-01-01

    Critical success factors for implementing supply chain information systems – Janne M. Denolf Due to intensified competition, companies realize that they should closely collaborate with their supply-chain partners to further cut costs and stay competitive. To do so, supply-chai

  1. Towards a framework of critical success factors for implementing supply-chain information systems

    NARCIS (Netherlands)

    Denolf, J.M.; Wognum, P.M.; Trienekens, J.H.; Vorst, van der J.G.A.J.; Omta, S.W.F.

    2015-01-01

    Supply chain information systems (SCISs) have emerged as the core of successful management in supply chains. However, the difficulties of SCIS implementations have been widely cited in the literature. Research on the critical success factors (CSFs) for SCIS implementation is rather scarce and

  2. Teaching the Banking System According to Critical Education. A Study of a Schoolbook on Economics

    Science.gov (United States)

    Vaina, Maria; Katidioti, Evaggelia; Ktitikos, Antonis

    2013-01-01

    The main objective of the current paper is to establish the deficiencies of teaching Economics in the Greek educational system. It also proposes critical education as a way of partially overcoming these issues and the way it can contribute to the protection of the everyday man and woman against the rising and current existential threats of the…

  3. Ethics Leadership in Research, Healthcare and Organizational Systems: Commentary and Critical Reflections

    Science.gov (United States)

    Gabriele, Edward F.

    2011-01-01

    In the last decades there has arisen a greater awareness of the ever present need for critical academic reflection on the nature of ethics leadership and committees in research, healthcare, and organizational systems. Yet what is meant by ethics itself? How is ethics understood as a historical phenomenon? What challenges must ethics leaders face…

  4. Self-organized criticality of power system faults and its application in adaptation to extreme climate

    Institute of Scientific and Technical Information of China (English)

    SU Sheng; LI YinHong; DUAN XianZhong

    2009-01-01

    This paper analyzes the statistics of faults in a transmission and distribution networks in central China, unveils long-term autocorrelation and power law distribution of power system faults, which indicates that power system fault has self-organized criticality (SOC) feature. The conclusion is consistent with the power systems data in 2008 with ice storm present. Since power systems cover large areas, climate is the key factor to its safety and stability. In-depth analysis shows that the SOC of atmosphere system contributes much to that of power system faults. Extreme climate will be more intense and frequent with global warming, it will have more and more impact upon power systems. The SOC feature of power system faults is utilized to develop approaches to facilitate power systems adaptation to climate varia-tion in an economical and efficient way.

  5. A Design That Incorporates Adaptive Reservation into Mixed-Criticality Systems

    Directory of Open Access Journals (Sweden)

    Fei Guan

    2017-01-01

    Full Text Available This paper presents a design and implementation of a Mixed-Criticality System (MCS extended from μC/OS III. It is based on a MCS model that uses an adaptive reservation mechanism to cope with the uncertainties in task execution times and to increase the resource utilization in MCS. The implementation takes advantage of the tasks’ recent execution records to predict their required computational resource in the near future and adjusts their reserved budget according to their criticality levels. The designed system focuses on soft real-time tasks. An overrun tolerance algorithm is used to limit the deadline miss ratios between a rise to the task’s actual consumption and the change to the amount of reservation. More than two criticality levels can be handled without introducing obvious additional overhead at each added level. The case study evaluation demonstrates that the reserved resource for each task is always close to its actual consumption; the tasks’ deadline misses are bounded by the different requirements specified by the criticality levels; during overload conditions, high-criticality tasks are guaranteed to have sufficient resource reservation. Although there is still room for improvement if it comes to processing overhead, this research brings some inspirations in both modelling and implementation aspects of MCS.

  6. Random-fractal Ansatz for the configurations of two-dimensional critical systems

    Science.gov (United States)

    Lee, Ching Hua; Ozaki, Dai; Matsueda, Hiroaki

    2016-12-01

    Critical systems have always intrigued physicists and precipitated the development of new techniques. Recently, there has been renewed interest in the information contained in the configurations of classical critical systems, whose computation do not require full knowledge of the wave function. Inspired by holographic duality, we investigated the entanglement properties of the classical configurations (snapshots) of the Potts model by introducing an Ansatz ensemble of random fractal images. By virtue of the central limit theorem, our Ansatz accurately reproduces the entanglement spectra of actual Potts snapshots without any fine tuning of parameters or artificial restrictions on ensemble choice. It provides a microscopic interpretation of the results of previous studies, which established a relation between the scaling behavior of snapshot entropy and the critical exponent. More importantly, it elucidates the role of ensemble disorder in restoring conformal invariance, an aspect previously ignored. Away from criticality, the breakdown of scale invariance leads to a renormalization of the parameter Σ in the random fractal Ansatz, whose variation can be used as an alternative determination of the critical exponent. We conclude by providing a recipe for the explicit construction of fractal unit cells consistent with a given scaling exponent.

  7. Overview of Risk Mitigation for Safety-Critical Computer-Based Systems

    Science.gov (United States)

    Torres-Pomales, Wilfredo

    2015-01-01

    This report presents a high-level overview of a general strategy to mitigate the risks from threats to safety-critical computer-based systems. In this context, a safety threat is a process or phenomenon that can cause operational safety hazards in the form of computational system failures. This report is intended to provide insight into the safety-risk mitigation problem and the characteristics of potential solutions. The limitations of the general risk mitigation strategy are discussed and some options to overcome these limitations are provided. This work is part of an ongoing effort to enable well-founded assurance of safety-related properties of complex safety-critical computer-based aircraft systems by developing an effective capability to model and reason about the safety implications of system requirements and design.

  8. System Guidelines for EMC Safety-Critical Circuits: Design, Selection, and Margin Demonstration

    Science.gov (United States)

    Lawton, R. M.

    1996-01-01

    Demonstration of required safety margins on critical electrical/electronic circuits in large complex systems has become an implementation and cost problem. These margins are the difference between the activation level of the circuit and the electrical noise on the circuit in the actual operating environment. This document discusses the origin of the requirement and gives a detailed process flow for the identification of the system electromagnetic compatibility (EMC) critical circuit list. The process flow discusses the roles of engineering disciplines such as systems engineering, safety, and EMC. Design and analysis guidelines are provided to assist the designer in assuring the system design has a high probability of meeting the margin requirements. Examples of approaches used on actual programs (Skylab and Space Shuttle Solid Rocket Booster) are provided to show how variations of the approach can be used successfully.

  9. Distributed Measuring System for Predictive Diagnosis of Uninterruptible Power Supplies in Safety-Critical Applications

    Directory of Open Access Journals (Sweden)

    Sergio Saponara

    2016-04-01

    Full Text Available This work proposes a scalable architecture of an Uninterruptible Power Supply (UPS system, with predictive diagnosis capabilities, for safety critical applications. A Failure Mode and Effect Analysis (FMEA has identified the faults occurring in the energy storage unit, based on Valve Regulated Lead-Acid batteries, and in the 3-phase high power transformers, used in switching converters and for power isolation, as the main bottlenecks for power system reliability. To address these issues, a distributed network of measuring nodes is proposed, where vibration-based mechanical stress diagnosis is implemented together with electrical (voltage, current, impedance and thermal degradation analysis. Power system degradation is tracked through multi-channel measuring nodes with integrated digital signal processing in the transformed frequency domain, from 0.1 Hz to 1 kHz. Experimental measurements on real power systems for safety-critical applications validate the diagnostic unit.

  10. Melancholia States in the Climate System: Exploring Global Instabilities and Critical Transitions

    CERN Document Server

    Lucarini, Valerio

    2016-01-01

    Multistability is a ubiquitous feature in systems of geophysical relevance and provides key challenges for our ability to predict a system's response to perturbations. Near critical transitions small causes can lead to large effects and - for all practical purposes - irreversible changes in the properties of the system. The Earth climate is multistable: present astronomical/astrophysical conditions support two stable regimes, the warm climate we live in, and a snowball climate, characterized by global glaciation. We first provide an overview of methods and ideas relevant for studying the climate response to forcings and focus on the properties of critical transitions in the context of both stochastic and deterministic dynamics, and assess strengths and weaknesses of simplified approaches. Following an idea developed by Eckhardt and co. for the investigation of multistable turbulent fluids, we study the global instability giving rise to the snowball/warm multistability in the climate system by identifying the ...

  11. Existence of least energy solutions to coupled elliptic systems with critical nonlinearities

    Directory of Open Access Journals (Sweden)

    Gong-Ming Wei

    2008-04-01

    Full Text Available In this paper we study the existence of nontrivial solutions of elliptic systems with critical nonlinearities and subcritical nonlinear coupling interactions, under Dirichlet or Neumann boundary conditions. These equations are motivated from solitary waves of nonlinear Schrodinger systems in physics. Using minimax theorem and by estimates on the least energy, we prove the existence of nonstandard least energy solutions, i.e. solutions with least energy and each component is nontrivial.

  12. Discrete Multiwavelet Critical-Sampling Transform-Based OFDM System over Rayleigh Fading Channels

    OpenAIRE

    Sameer A. Dawood; Malek, F.; M. S. ANUAR; Suha Q. Hadi

    2015-01-01

    Discrete multiwavelet critical-sampling transform (DMWCST) has been proposed instead of fast Fourier transform (FFT) in the realization of the orthogonal frequency division multiplexing (OFDM) system. The proposed structure further reduces the level of interference and improves the bandwidth efficiency through the elimination of the cyclic prefix due to the good orthogonality and time-frequency localization properties of the multiwavelet transform. The proposed system was simulated using MATL...

  13. Contribution to the study of the vulnerability of critical systems to Intentional Electromagnetic Interference (IEMI)

    OpenAIRE

    Mora Parra, Nicolas

    2016-01-01

    The progress of high power electromagnetic (HPEM) sources during the late 1990s raised the concern in the electromagnetic compatibility (EMC) community that they could be deployed for criminal purposes to interfere with the operation of modern electronic systems. It is well established that sufficiently intense electromagnetic fields can cause upset or damage in electronic systems and therefore, can affect almost every critical infrastructure (CI) that is based on information and communicatio...

  14. INVIGORATING WORLD SYSTEM THEORY as CRITICAL THEORY: Exploring Philosophical Foundations and Postpositivist Contributions

    Directory of Open Access Journals (Sweden)

    Kurt Burch

    1995-08-01

    Full Text Available World system theory comprises two distinct lines of inquiry: macro-social studies of historical world-systems and ideological critique. World system theorists often shun ideological critique, but for two reasons I argue it must be foremost. First, without explicit attention to its philosophical foundations, world system theory rests upon several unexamined, uncomplementary, liberal premises. These premises pose conceptual puzzles. World system theorists frequently cast such puzzles as methodological, empirical, or theoretical problems, rather than as symptoms of ideological confusions requiring critique. Second, through explicit critique, theorists may transform implicit philosophical foundations into explicit ontological and epistemological groundings. Such groundings will enable world system theorists to better realize their critical, emancipatory goals and to resolve theoretical puzzles. One such puzzle -- the conceptual distinction between politics and economics -- recurs often, arising in the debates on the relation(s between the state system and capitalism and thwarting efforts to demonstrate the unity of the world system. I suggest that world system theorists engage in explicit ideological critique to lay equally explicit ideologicalfoundations for their histories. I suggest a critical, conceptually historicist, "constructivist" approach that builds upon postpositivist critiques and introduces constitutive principles. I illustrate the virtue of this approach by demonstrating the unity of the modern world system.

  15. FRACTAL DIMENSION OF TIME SERIES APPLIED TO IDENTIFICATION OF CRITICAL SPEED OF JEFFCOTT ROTOR SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Zhao Yucheng; Sun Kun; Zhang Yahong; Xu Qingyu

    2005-01-01

    The dynamical behaviors of logistic map(May's model) and duffing equation are studied through fractal dimension of time series at different parameters. It is shown that the parameters of dynamical behaviors can be identified effectively by the curve of fractal dimension with parameter increments. For further verification, the relation between the fractional dimension of time series and rotational speed can be used to identify critical speed effectively by using this method to a plate Jeffoctt rotor system. The numerical and experimental result indicates that the identification of critical parameters is effective.

  16. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Directory of Open Access Journals (Sweden)

    Segun Goh

    Full Text Available Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare bus stops are transformed into a (renormalized "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  17. Emergence of criticality in the transportation passenger flow: scaling and renormalization in the Seoul bus system.

    Science.gov (United States)

    Goh, Segun; Lee, Keumsook; Choi, Moo Young; Fortin, Jean-Yves

    2014-01-01

    Social systems have recently attracted much attention, with attempts to understand social behavior with the aid of statistical mechanics applied to complex systems. Collective properties of such systems emerge from couplings between components, for example, individual persons, transportation nodes such as airports or subway stations, and administrative districts. Among various collective properties, criticality is known as a characteristic property of a complex system, which helps the systems to respond flexibly to external perturbations. This work considers the criticality of the urban transportation system entailed in the massive smart card data on the Seoul transportation network. Analyzing the passenger flow on the Seoul bus system during one week, we find explicit power-law correlations in the system, that is, power-law behavior of the strength correlation function of bus stops and verify scale invariance of the strength fluctuations. Such criticality is probed by means of the scaling and renormalization analysis of the modified gravity model applied to the system. Here a group of nearby (bare) bus stops are transformed into a (renormalized) "block stop" and the scaling relations of the network density turn out to be closely related to the fractal dimensions of the system, revealing the underlying structure. Specifically, the resulting renormalized values of the gravity exponent and of the Hill coefficient give a good description of the Seoul bus system: The former measures the characteristic dimensionality of the network whereas the latter reflects the coupling between distinct transportation modes. It is thus demonstrated that such ideas of physics as scaling and renormalization can be applied successfully to social phenomena exemplified by the passenger flow.

  18. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.; Turner, J.C.

    1992-12-01

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO{sub 2}F{sub 2} and H{sub 2}O) and hydrofluoric-acid-moderated uranium hexaflouride (UF{sub 6} and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % {sup 235}U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  19. Minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, W.C.; Turner, J.C.

    1992-12-01

    A parametric calculational analysis has been performed in order to estimate the minimum mass of moderator required for criticality of homogeneous low-enriched uranium systems. The analysis was performed using a version of the SCALE-4.0 code system and the 27-group ENDF/B-IV cross-section library. Water-moderated uranyl fluoride (UO[sub 2]F[sub 2] and H[sub 2]O) and hydrofluoric-acid-moderated uranium hexaflouride (UF[sub 6] and HF) systems were considered in the analysis over enrichments of 1.4 to 5 wt % [sup 235]U. Estimates of the minimum critical volume, minimum critical mass of uranium, and the minimum mass of moderator required for criticality are presented. There was significant disagreement between the values generated in this study when compared with a similar undocumented study performed in 1983 using ANISN and the Knight-modified Hansen-Roach cross sections. An investigation into the cause of the disagreement was made, and the results are presented.

  20. On Measuring the Criticality of Various Variables and Processes in Organization Information Systems: Proposed Methodological Procedure

    Directory of Open Access Journals (Sweden)

    Jagdish PATHAK

    2010-01-01

    Full Text Available This paper proposes methodological procedures to be used by the accounting, organizational and managerial researchers and executives to ascertain the criticality of the variables and the processes in the measurement of management control system. We have restricted the validation of proposed methods to the extraction of critical success factors (CSF in this study. We have also provided a numerical illustration and tested our methodological procedures using a dataset of an empirical study conducted for the purpose of ascertaining the CSFs. The proposed methods can be used by the researchers in accounting, organizational information systems, economics, and business and also in other relevant disciplines of organizational sciences. The main contribution of this paper is the extension of Rockart’s work [33] on critical success factors. We have extended the theory of CSF beyond the initially suggested domain of information into management control system decision making. The methodological procedures developed by us are expected to enrich the literature of analytical and empirical studies in accounting and organizational areas where it can prove helpful in understanding the criticality of individual variables, processes, methods or success factors.

  1. Regulating critical period plasticity: insight from the visual system to fear circuitry for therapeutic interventions.

    Science.gov (United States)

    Nabel, Elisa M; Morishita, Hirofumi

    2013-01-01

    Early temporary windows of heightened brain plasticity called critical periods developmentally sculpt neural circuits and contribute to adult behavior. Regulatory mechanisms of visual cortex development - the preeminent model of experience-dependent critical period plasticity-actively limit adult plasticity and have proved fruitful therapeutic targets to reopen plasticity and rewire faulty visual system connections later in life. Interestingly, these molecular mechanisms have been implicated in the regulation of plasticity in other functions beyond vision. Applying mechanistic understandings of critical period plasticity in the visual cortex to fear circuitry may provide a conceptual framework for developing novel therapeutic tools to mitigate aberrant fear responses in post traumatic stress disorder. In this review, we turn to the model of experience-dependent visual plasticity to provide novel insights for the mechanisms regulating plasticity in the fear system. Fear circuitry, particularly fear memory erasure, also undergoes age-related changes in experience-dependent plasticity. We consider the contributions of molecular brakes that halt visual critical period plasticity to circuitry underlying fear memory erasure. A major molecular brake in the visual cortex, perineuronal net formation, recently has been identified in the development of fear systems that are resilient to fear memory erasure. The roles of other molecular brakes, myelin-related Nogo receptor signaling and Lynx family proteins - endogenous inhibitors for nicotinic acetylcholine receptor, are explored in the context of fear memory plasticity. Such fear plasticity regulators, including epigenetic effects, provide promising targets for therapeutic interventions.

  2. Regulating Critical Period Plasticity: Insight from the Visual System to Fear Circuitry for Therapeutic Interventions

    Directory of Open Access Journals (Sweden)

    Elisa M. Nabel

    2013-11-01

    Full Text Available Early temporary windows of heightened brain plasticity called critical periods developmentally sculpt neural circuits and contribute to adult behavior. Regulatory mechanisms of visual cortex development –the preeminent model of experience-dependent critical period plasticity- actively limit adult plasticity and have proved fruitful therapeutic targets to reopen plasticity and rewire faulty visual system connections later in life. Interestingly, these molecular mechanisms have been implicated in the regulation of plasticity in other functions beyond vision. Applying mechanistic understandings of critical period plasticity in the visual cortex to fear circuitry may provide a conceptual framework for developing novel therapeutic tools to mitigate aberrant fear responses in post traumatic stress disorder. In this review, we turn to the model of experience-dependent visual plasticity to provide novel insights for the mechanisms regulating plasticity in the fear system. Fear circuitry, particularly fear memory erasure, also undergoes age-related changes in experience-dependent plasticity. We consider the contributions of molecular brakes that halt visual critical period plasticity to circuitry underlying fear memory erasure. A major molecular brake in the visual cortex, perineuronal net formation, recently has been identified in the development of fear systems that are resilient to fear memory erasure. The roles of other molecular brakes, myelin-related Nogo receptor signaling and Lynx family proteins– endogenous inhibitors for nicotinic acetylcholine receptor, are explored in the context of fear memory plasticity. Such fear plasticity regulators, including epigenetic effects, provide promising targets for therapeutic interventions.

  3. Attractive forces study in macromolecules and critical systems; Etude des forces attractives dans les macromolecules et les systemes critiques

    Energy Technology Data Exchange (ETDEWEB)

    Penninckx-Sans, A.

    1995-07-10

    The attractive forces effect is particularly interesting at the proximity of a critical point. In a liquid system, there are two kinds of attractive forces in presence : the forces bound to the solution volume and those generated by the presence of the solution surface or by a solution interface. In the first case, the attractive forces are the more important as the system is in a critical field. For this study, the selected example is a polymer solution in a two solvents mixture. A formulation in terms of way integrals as part of statistical physics has lead us to find again some known results on the polymer chain conformation in the presence of two solvents (collapse of the polymer on itself) far from the critical point and to extend these results to the critical field. In the case of attractive forces created by the surface in some critical systems (polymer of infinite size in solution and binary mixture near the de mixture point), the adsorption profile created by the attraction of one specie by the surface, follows a scale law. The optical methods usually used for the study of these systems do not give characteristic sign of concentration profile in power law. In the case where the interaction potential between radiation and matter is attractive, the reflectivity gives a separate mark of the existence of the scale law in the form of a resonance. After some theoretical forecasts, the author has used this method on the binary mixture methanol-cyclohexane in order to reveal experimentally a reflectivity pseudo-discontinuity and then the existence of the power law in the critical adsorption profile. (O.L.). 69 refs., 60 tabs.

  4. Critical behavior in reaction-diffusion systems exhibiting absorbing phase transition

    CERN Document Server

    Ódor, G

    2003-01-01

    Phase transitions of reaction-diffusion systems with site occupation restriction and with particle creation that requires n>1 parents and where explicit diffusion of single particles (A) exists are reviewed. Arguments based on mean-field approximation and simulations are given which support novel kind of non-equilibrium criticality. These are in contradiction with the implications of a suggested phenomenological, multiplicative noise Langevin equation approach and with some of recent numerical analysis. Simulation results for the one and two dimensional binary spreading 2A -> 4A, 4A -> 2A model display a new type of mean-field criticality characterized by alpha=1/3 and beta=1/2 critical exponents suggested in cond-mat/0210615.

  5. The impact of natural hazard on critical infrastructure systems: definition of an ontology

    Science.gov (United States)

    Dimauro, Carmelo; Bouchon, Sara; Frattini, Paolo; Giusto, Claudia

    2013-04-01

    According to the Council of the European Union Directive (2008), 'critical infrastructure' means an asset, system or part thereof which is essential for the maintenance of vital societal functions, health, safety, security, economic or social well-being of people, and the disruption or destruction of which would have a significant impact as a result of the failure to maintain those functions. Critical infrastructure networks are exposed to natural events, such as floods, storms, landslides, earthquakes, etc. Recent natural disasters show that socio-economic consequences can be very much aggravated by the impact on these infrastructures. Though, there is still a lack of a recognized approach or methodology to assess the vulnerability of critical infrastructure assets against natural threats. The difficulty to define such an approach is increased by the need to consider a very high number of natural events, which differ in nature, magnitude and probability, as well as the need to assess the vulnerability of a high variety of infrastructure assets (e.g. bridges, roads, tunnels, pipelines, etc.) To meet this challenge, the objective of the THREVI2 EU-CIPS project is to create a database linking the relationships between natural hazards and critical infrastructure assets. The query of the database will allow the end-users (critical infrastructure protection authorities and operators) to identify the relevant scenarios according to the own priorities and criteria. The database builds on an ontology optimized for the assessment of the impact of threats on critical infrastructures. The ontology aims at capturing the existing knowledge on natural hazards, critical infrastructures assets and their related vulnerabilities. Natural phenomena that can threaten critical infrastructures are classified as "events", and organized in a genetic-oriented hierarchy. The main attributes associated to each event are the probability, the magnitude and the "modus". The modus refers to the

  6. A Macroscopic Description of a Generalized Self-organized Criticality System: Astrophysical Applications

    Science.gov (United States)

    Aschwanden, Markus J.

    2014-02-01

    We suggest a generalized definition of self-organized criticality (SOC) systems: SOC is a critical state of a nonlinear energy dissipation system that is slowly and continuously driven toward a critical value of a system-wide instability threshold, producing scale-free, fractal-diffusive, and intermittent avalanches with power law-like size distributions. We develop here a macroscopic description of SOC systems that provides an equivalent description of the complex microscopic fine structure, in terms of fractal-diffusive transport (FD-SOC). Quantitative values for the size distributions of SOC parameters (length scales L, time scales T, waiting times Δt, fluxes F, and fluences or energies E) are derived from first principles, using the scale-free probability conjecture, N(L)dLvpropL -d , for Euclidean space dimension d. We apply this model to astrophysical SOC systems, such as lunar craters, the asteroid belt, Saturn ring particles, magnetospheric substorms, radiation belt electrons, solar flares, stellar flares, pulsar glitches, soft gamma-ray repeaters, black-hole objects, blazars, and cosmic rays. The FD-SOC model predicts correctly the size distributions of 8 out of these 12 astrophysical phenomena, and indicates non-standard scaling laws and measurement biases for the others.

  7. Sustainability from the Occurrence of Critical Dynamic Power System Blackout Determined by Using the Stochastic Event Tree Technique

    National Research Council Canada - National Science Library

    Muhammad Murtadha Othman; Nur Ashida Salim; Ismail Musirin

    2017-01-01

    .... This paper presents the proposed stochastic event tree technique used to assess the sustainability against the occurrence of dynamic power system blackout emanating from implication of critical...

  8. Half the entanglement in critical systems is distillable from a single specimen

    CERN Document Server

    Orus, R; Eisert, J; Cramer, M

    2005-01-01

    We establish that the leading critical scaling of the single-copy entanglement is exactly one half of the entropy of entanglement of a block in critical infinite spin chains in a general setting, using methods of conformal field theory. Conformal symmetry imposes that the single-copy entanglement for critical many-body systems scales as E_1(\\rho_L)=(c/6) \\log L- (c/6) (\\pi^2/\\log L) + O(1/L), where L is the number of qubits in a block of an infinite spin chain and c corresponds to the central charge. This proves that from a single specimen of a spin critical chain, already half the entanglement can be distilled compared to the rate that is asymptotically available. The result is substantiated by a similar quantitative analysis for all translationally invariant quantum spin chains corresponding to general isotropic quasi-free fermionic models. An analytic example of the XY model shows that away from criticality the above simple relation is only maintained near the quantum phase transition point.

  9. CFD Analysis of the Primary Cooling System for the Small Modular Natural Circulation Lead Cooled Fast Reactor SNRLFR-100

    OpenAIRE

    Pengcheng Zhao; Kangli Shi; Shuzhou Li; Jingchao Feng; Hongli Chen

    2016-01-01

    Small modular reactor (SMR) has drawn wide attention in the past decades, and Lead cooled fast reactor (LFR) is one of the most promising advanced reactors which are able to meet the safety economic goals of Gen-IV nuclear energy systems. A small modular natural circulation lead cooled fast reactor-100 MWth (SNRLFR-100) is being developed by University of Science and Technology of China (USTC). In the present work, a 3D CFD model, primary heat exchanger model, fuel pin model, and point kineti...

  10. [The critical incident reporting system as an instrument of risk management for better patient safety].

    Science.gov (United States)

    Panzica, M; Krettek, C; Cartes, M

    2011-09-01

    The probability that an inpatient will be harmed by a medical procedure is at least 3% of all patients. As a consequence, hospital risk management has become a central management task in the health care sector. The critical incident reporting system (CIRS) as a voluntary instrument for reporting (near) incidents plays a key role in the implementation of a risk management system. The goal of the CIRS is to register system errors without assigning guilt or meting out punishment and at the same time increasing the number of voluntary reports.

  11. CLASSIFICATION OF POSITIVE SOLUTIONS FOR NONLINEAR DIFFERENTIAL AND INTEGRAL SYSTEMS WITH CRITICAL EXPONENTS

    Institute of Scientific and Technical Information of China (English)

    Wenxiong Chen; Congming Li

    2009-01-01

    We classify all positive solutions for the following integral system……Here fi(u), 1≤i≤m, are real-valued functions of homogeneous degree n+α/n-α and aremonotone nondecreasing with respect to all the independent variables u1, u2, ..', um. In the special case n>3 and α= 2, we show that the above system is equivalent to the following elliptic PDE system………This system is closely related to the stationary Schrodinger system with critical exponents for Bose-Einstein condensate.

  12. Change management and clinical engagement: critical elements for a successful clinical information system implementation.

    Science.gov (United States)

    Detwiller, Maureen; Petillion, Wendy

    2014-06-01

    Moving a large healthcare organization from an old, nonstandardized clinical information system to a new user-friendly, standards-based system was much more than an upgrade to technology. This project to standardize terminology, optimize key processes, and implement a new clinical information system was a large change initiative over 4 years that affected clinicians across the organization. Effective change management and engagement of clinical stakeholders were critical to the success of the initiative. The focus of this article was to outline the strategies and methodologies used and the lessons learned.

  13. System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system

    Institute of Scientific and Technical Information of China (English)

    穆景阳; 陈江平; 陈芝久

    2003-01-01

    As an environmentally harmless and feasible alternate refrigerant, CO2 has attracted worldwide attention, especially in the area of automobile air-conditioning (AAC). The thermal property of CO2 and its trans-critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO2 AAC system.

  14. Locally converging algorithms for determining the critical temperature in Ising systems

    Science.gov (United States)

    Faraggi, Eshel; Robb, Daniel T.

    2008-10-01

    We introduce a class of algorithms that converge to criticality automatically, in a way similar to the invaded cluster algorithm. Unlike the invaded cluster algorithm which uses global percolation as a test for criticality, these local algorithms use an average over local observables, specifically the number of satisfied bonds, in a feedback loop which drives the system toward criticality. Two specific algorithms are introduced, the average algorithm and the locally converging Wolff algorithm. We apply these algorithms to study the Ising square lattice and the Ising Bethe lattice. We find reasonable convergence to the critical temperature for both systems under the locally converging Wolff algorithm. We also re-examine the phase diagram of the dilute two-dimensional (2D) Ising model and find results supporting our previously reported conclusions regarding the existence of a local regime of magnetization below the percolations threshold. In addition, the presented algorithms are computationally more efficient than the invaded cluster algorithm, requiring less CPU time and memory.

  15. Holographic view on quantum correlations and mutual information between disjoint blocks of a quantum critical system

    Science.gov (United States)

    Molina-Vilaplana, Javier; Sodano, Pasquale

    2011-10-01

    In ( d + 1) dimensional Multiscale Entanglement Renormalization Ansatz (MERA) networks, tensors are connected so as to reproduce the discrete, ( d + 2) holographic geometry of Anti de Sitter space (AdS d+2) with the original system lying at the boundary. We analyze the MERA renormalization flow that arises when computing the quantum correlations between two disjoint blocks of a quantum critical system, to show that the structure of the causal cones characteristic of MERA, requires a transition between two different regimes attainable by changing the ratio between the size and the separation of the two disjoint blocks. We argue that this transition in the MERA causal developments of the blocks may be easily accounted by an AdS d+2 black hole geometry when the mutual information is computed using the Ryu-Takayanagi formula. As an explicit example, we use a BTZ AdS3 black hole to compute the MI and the quantum correlations between two disjoint intervals of a one dimensional boundary critical system. Our results for this low dimensional system not only show the existence of a phase transition emerging when the conformal four point ratio reaches a critical value but also provide an intuitive entropic argument accounting for the source of this instability. We discuss the robustness of this transition when finite temperature and finite size effects are taken into account.

  16. Software reliability - Measures and effects in flight critical digital avionics systems

    Science.gov (United States)

    Dunn, William R.

    1986-01-01

    The paper discusses software reliability as it applies particularly to design and evaluation of flight-critical digital avionics systems. Measures of software reliability, measurement methods and reliability (macro-) models are discussed. Recent work assessing their accuracy in predicting software errors in 'fly-by-wire' Newtonian applications is presented. Additional, detailed topics are discussed including software error distributions (e.g. catastrophic vs. noncatastrophic) and the effects of system growth/maturity on reliability improvement. In practical flight-critical digital applications, software reliability improvement is sought through use of parallel, redundant software (i.e. N-version programming) or backup software that can be invoked in the event of (primary) software failure. Achievable reliability levels are however highly sensitive to common-mode specification and programming errors. Recent data correlating these errors with net software reliability are discussed.

  17. Impact Responses of Composite Cushioning System considering Critical Component with Simply Supported Beam Type

    Directory of Open Access Journals (Sweden)

    Fu-de Lu

    2014-04-01

    Full Text Available In some microelectronic products, one or several components can be idealized as simply supported beam type and viewed as vulnerable elements or critical component due to the fact that they are destroyed easily under impact loadings. The composite cushioning structure made of expanded polyethylene (EPE, and expanded polystyrene (EPS was utilized to protect the vulnerable elements against impact loadings during transportation. The vibration equations of composite cushioning system were deducted and virtual mass method was applied to predict impact behavior of critical component. Numerical results indicate that virtual mass method is appropriate for computing impact response of composite cushioning system with vulnerable element of simply supported beam type, which is affirmed by the fact that the impact responses of structure element in terms of velocity- and displacement-time curves are almost unchanged when virtual mass is smaller than a certain value. The results in this paper make it possible for installation of packaging optimization design.

  18. Phase transitions, nonequilibrium dynamics, and critical behavior of strongly interacting systems

    Energy Technology Data Exchange (ETDEWEB)

    Mottola, E.; Bhattacharya, T.; Cooper, F. [and others

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development project at Los Alamos National Laboratory. In this effort, large-scale simulations of strongly interacting systems were performed and a variety of approaches to the nonequilibrium dynamics of phase transitions and critical behavior were investigated. Focus areas included (1) the finite-temperature quantum chromodynamics phase transition and nonequilibrium dynamics of a new phase of matter (the quark-gluon plasma) above the critical temperature, (2) nonequilibrium dynamics of a quantum fields using mean field theory, and (3) stochastic classical field theoretic models with applications to spinodal decomposition and structural phase transitions in a variety of systems, such as spin chains and shape memory alloys.

  19. Design of Critical Control Systems for Non-Minimum Phase Plants via LTR Technique

    Science.gov (United States)

    Ishihara, Tadashi; Ono, Takahiko

    An application of the loop transfer recovery (LTR) technique to critical control systems design is proposed for non-minimum phase plants. The controller structure is chosen as the Davison type integral controller with the Kalman filter. First, a critical control system is designed on the assumption that the state of the minimum phase part of the plant can be used for the feedback. A quadratic performance index with tuning parameters is used for determining the partial state feedback gain matrix. Second, the Kalman filter gain matrix is determined such that the output feedback controller performs as in the partial state feedback controller. The formal partial loop recovery procedure using the Riccati equation is adopted for this purpose. The proposed design method requires much simpler numerical search than the conventional one-step approach. An illustrative design example is presented.

  20. Moment Stability of the Critical Case of PWM Feedback Systems with Stochastic Perturbations

    Directory of Open Access Journals (Sweden)

    Zhong Zhang

    2012-01-01

    Full Text Available This paper further studies the moment stability of pulse-width-modulated (PWM feedback system which is subjected to multiplicative and additive random disturbance modeled by the derivative of Wiener process. Different from the existing investigation, we focus on its critical case. The linear plant considered herein is assumed to be critically stable; that is, the plant has one and only one pole at the origin, and the rest of the poles are left half of complex plane. We establish several globally asymptotically stability criteria for such PWM feedback systems and then propose an algorithm to calculate the stability bound effectively. Furthermore, we present two numerical examples to show the effectiveness of the theoretical results.

  1. Self-organized criticality in glassy spin systems requires long-range interactions

    Science.gov (United States)

    Andresen, Juan Carlos; Andrist, Ruben S.; Katzgraber, Helmut G.; Dobrosavljevic, Vladimir; Zimanyi, Gergerly T.

    2013-03-01

    We investigate the conditions required for general spin systems with frustration and disorder to display self-organized criticality, a property which so far has been established in spin models only for the infinite-range Sherringtion-Kirkpatrick Ising spin-glass model [PRL 83, 1034 (1999)]. We study the avalanche and the magnetization jump distribution triggered by an external magnetic field in the short-range Edward-Anderson Ising spin glass for various space dimensions, between 2 and 8. Our numerical results, obtained on systems of unprecedented size, demonstrate that self-organized criticality is recovered only in the strict limit of infinite space dimensions (or equivalently of long-ranged interaction), and is not a generic property of spin-glass models in finite space dimensions.

  2. 'Known Secure Sensor Measurements' for Critical Infrastructure Systems: Detecting Falsification of System State

    Energy Technology Data Exchange (ETDEWEB)

    Miles McQueen; Annarita Giani

    2011-09-01

    This paper describes a first investigation on a low cost and low false alarm, reliable mechanism for detecting manipulation of critical physical processes and falsification of system state. We call this novel mechanism Known Secure Sensor Measurements (KSSM). The method moves beyond analysis of network traffic and host based state information, in fact it uses physical measurements of the process being controlled to detect falsification of state. KSSM is intended to be incorporated into the design of new, resilient, cost effective critical infrastructure control systems. It can also be included in incremental upgrades of already in- stalled systems for enhanced resilience. KSSM is based on known secure physical measurements for assessing the likelihood of an attack and will demonstrate a practical approach to creating, transmitting, and using the known secure measurements for detection.

  3. The Ramifications of Meddling with Systems Governed by Self-organized Critical Dynamics

    Science.gov (United States)

    Carreras, B. A.; Newman, D. E.; Dobson, I.

    2002-12-01

    Complex natural, well as man-made, systems often exhibit characteristics similar to those seen in self-organized critical (SOC) systems. The concept of self-organized criticality brings together ideas of self-organization of nonlinear dynamical systems with the often-observed near critical behavior of many natural phenomena. These phenomena exhibit self-similarities over extended ranges of spatial and temporal scales. In those systems, scale lengths may be described by fractal geometry and time scales that lead to 1/f-like power spectra. Natural applications include modeling the motion of tectonics plates, forest fires, magnetospheric dynamics, spin glass systems, and turbulent transport. In man-made systems, applications have included traffic dynamics, power and communications networks, and financial markets among many others. Simple cellular automata models such as the running sandpile model have been very useful in reproducing the complexity and characteristics of these systems. One characteristic property of the SOC systems is that they relax through what we call events. These events can happen over all scales of the system. Examples of these events are: earthquakes in the case of plate tectonic; fires in forest evolution extinction in the co evolution of biological species; and blackouts in power transmission systems. In a time-averaged sense, these systems are subcritical (that is, they lie in an average state that should not trigger any events) and the relaxation events happen intermittently. The time spent in a subcritical state relative to the time of the events varies from one system to another. For instance, the chance of finding a forest on fire is very low with the frequency of fires being on the order of one fire every few years and with many of these fires small and inconsequential. Very large fires happen over time periods of decades or even centuries. However, because of their consequences, these large but infrequent events are the important ones

  4. CRITICAL DAMPING OF THE SECOND-ORDER PENDULUM-LIKE SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    李鑫滨; 黄永念; 杨莹; 黄琳

    2005-01-01

    First, the properties of solutions of a typical second-order pendulum-like system with a specified nonlinear function were discussed. Then the case with a general form of nonlinearity is considered and its global properties were studied by using the qualitative theory of differential equations. As a result, sufficient conditions for estimating the critical damp are established, which improves the work by Leonov et al.

  5. Percolation and nucleation approaches to nuclear fragmentation: criticality in very small systems

    Energy Technology Data Exchange (ETDEWEB)

    Santiago, A.J. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Chung, K.C.

    1994-12-01

    Different criteria for criticality in very small systems are discussed in the context of percolation and nucleation approaches to nuclear fragmentation. It is shown that the probability threshold in percolation and interaction radius threshold in nucleation are very strongly dependent upon the adopted criterion. By using Monte Carlo method, similarities and dissimilarities between nucleation and percolation pictures are also pointed out. (author). 17 refs, 5 figs, 2 tabs.

  6. Development of a structural health monitoring system for the life assessment of critical transportation infrastructure.

    Energy Technology Data Exchange (ETDEWEB)

    Roach, Dennis Patrick; Jauregui, David Villegas (New Mexico State University, Las Cruces, NM); Daumueller, Andrew Nicholas (New Mexico State University, Las Cruces, NM)

    2012-02-01

    Recent structural failures such as the I-35W Mississippi River Bridge in Minnesota have underscored the urgent need for improved methods and procedures for evaluating our aging transportation infrastructure. This research seeks to develop a basis for a Structural Health Monitoring (SHM) system to provide quantitative information related to the structural integrity of metallic structures to make appropriate management decisions and ensuring public safety. This research employs advanced structural analysis and nondestructive testing (NDT) methods for an accurate fatigue analysis. Metal railroad bridges in New Mexico will be the focus since many of these structures are over 100 years old and classified as fracture-critical. The term fracture-critical indicates that failure of a single component may result in complete collapse of the structure such as the one experienced by the I-35W Bridge. Failure may originate from sources such as loss of section due to corrosion or cracking caused by fatigue loading. Because standard inspection practice is primarily visual, these types of defects can go undetected due to oversight, lack of access to critical areas, or, in riveted members, hidden defects that are beneath fasteners or connection angles. Another issue is that it is difficult to determine the fatigue damage that a structure has experienced and the rate at which damage is accumulating due to uncertain history and load distribution in supporting members. A SHM system has several advantages that can overcome these limitations. SHM allows critical areas of the structure to be monitored more quantitatively under actual loading. The research needed to apply SHM to metallic structures was performed and a case study was carried out to show the potential of SHM-driven fatigue evaluation to assess the condition of critical transportation infrastructure and to guide inspectors to potential problem areas. This project combines the expertise in transportation infrastructure at New

  7. Some Challenges in the Design of Human-Automation Interaction for Safety-Critical Systems

    Science.gov (United States)

    Feary, Michael S.; Roth, Emilie

    2014-01-01

    Increasing amounts of automation are being introduced to safety-critical domains. While the introduction of automation has led to an overall increase in reliability and improved safety, it has also introduced a class of failure modes, and new challenges in risk assessment for the new systems, particularly in the assessment of rare events resulting from complex inter-related factors. Designing successful human-automation systems is challenging, and the challenges go beyond good interface development (e.g., Roth, Malin, & Schreckenghost 1997; Christoffersen & Woods, 2002). Human-automation design is particularly challenging when the underlying automation technology generates behavior that is difficult for the user to anticipate or understand. These challenges have been recognized in several safety-critical domains, and have resulted in increased efforts to develop training, procedures, regulations and guidance material (CAST, 2008, IAEA, 2001, FAA, 2013, ICAO, 2012). This paper points to the continuing need for new methods to describe and characterize the operational environment within which new automation concepts are being presented. We will describe challenges to the successful development and evaluation of human-automation systems in safety-critical domains, and describe some approaches that could be used to address these challenges. We will draw from experience with the aviation, spaceflight and nuclear power domains.

  8. Automated implementation of rule-based expert systems with neural networks for time-critical applications

    Science.gov (United States)

    Ramamoorthy, P. A.; Huang, Song; Govind, Girish

    1991-01-01

    In fault diagnosis, control and real-time monitoring, both timing and accuracy are critical for operators or machines to reach proper solutions or appropriate actions. Expert systems are becoming more popular in the manufacturing community for dealing with such problems. In recent years, neural networks have revived and their applications have spread to many areas of science and engineering. A method of using neural networks to implement rule-based expert systems for time-critical applications is discussed here. This method can convert a given rule-based system into a neural network with fixed weights and thresholds. The rules governing the translation are presented along with some examples. We also present the results of automated machine implementation of such networks from the given rule-base. This significantly simplifies the translation process to neural network expert systems from conventional rule-based systems. Results comparing the performance of the proposed approach based on neural networks vs. the classical approach are given. The possibility of very large scale integration (VLSI) realization of such neural network expert systems is also discussed.

  9. Multisensor system for the protection of critical infrastructure of a seaport

    Science.gov (United States)

    Kastek, Mariusz; Dulski, Rafał; Zyczkowski, Marek; Szustakowski, Mieczysław; Trzaskawka, Piotr; Ciurapinski, Wiesław; Grelowska, Grazyna; Gloza, Ignacy; Milewski, Stanislaw; Listewnik, Karol

    2012-06-01

    There are many separated infrastructural objects within a harbor area that may be considered "critical", such as gas and oil terminals or anchored naval vessels. Those objects require special protection, including security systems capable of monitoring both surface and underwater areas, because an intrusion into the protected area may be attempted using small surface vehicles (boats, kayaks, rafts, floating devices with weapons and explosives) as well as underwater ones (manned or unmanned submarines, scuba divers). The paper will present the concept of multisensor security system for a harbor protection, capable of complex monitoring of selected critical objects within the protected area. The proposed system consists of a command centre and several different sensors deployed in key areas, providing effective protection from land and sea, with special attention focused on the monitoring of underwater zone. The initial project of such systems will be presented, its configuration and initial tests of the selected components. The protection of surface area is based on medium-range radar and LLTV and infrared cameras. Underwater zone will be monitored by a sonar and acoustic and magnetic barriers, connected into an integrated monitoring system. Theoretical analyses concerning the detection of fast, small surface objects (such as RIB boats) by a camera system and real test results in various weather conditions will also be presented.

  10. Controlling sewer systems – a critical review based on systems in three EU cities

    DEFF Research Database (Denmark)

    Mollerup, Ane Loft; Mikkelsen, Peter Steen; Thornberg, D.

    2017-01-01

    . With the basis of existing frameworks for control system design, a new time-scale dependent framework is proposed. We believe this comprehensive time-scale dependent framework can help water utilities to retrofit and design new control solutions and facilitate knowledge sharing about existing designs.......The term Real Time Control (RTC) is widely used to describe all types of control systems in sewer systems. Today the term covers everything from the simplest to the most advanced types of control systems, making it difficult to communicate about sewer system control in a precise manner, as well...... as search and find specific types of control systems for comparison. Through a survey of implemented control systems in three EU cities today and with the perspectives of current research within the field of sewer system control, the needs for a new control system design framework is identified...

  11. Approximation and Filtering Techniques for Navigation Data in Time-critical Electronic Warfare Systems

    Directory of Open Access Journals (Sweden)

    Vanitha D.

    2013-03-01

    Full Text Available This paper presents a holistic solution to the navigation requirements in a time critical electronic warfare systems like missile warning systems (MWS. In a passive MWS using IR sensors the efficiency of the system is determined by attributes such as low false alarm rate, minimal response time and ability to track different IR radiating objects by association and correlation of consecutive detections through time. Such a system is required to be supported by a navigation system capable of accurate estimation of the aircraft position, attitude angles and altitude. In this paper, estimation techniques used to accurately calculate aircraft navigation data at the time of capture of IR frames are discussed. The paper discusses about synchronization of INGPS, IR sensors & Processor on to same timeline. The paper also intends to evaluate the performance of wavelet transform filter in effective elimination of noise in navigation parameters like acceleration and attitude angle rates for a better estimation of position and attitude.

  12. New real-space renormalization-group calculation for the critical properties of lattice spin systems

    Science.gov (United States)

    Hecht, Charles E.; Kikuchi, Ryoichi

    1982-05-01

    In evaluating the critical properties of lattice spin systems in the real-space renormalization-group theory we use the cluster variation method. A configuration in the transformed system is constrained and the probability of occurrence of this configuration is calculated both in the transformed system and in the original system. By equating the two probabilities and forming ratios of two such equalities (for two or more constrained configurations) the fixed point of the renormalization transformation is evaluated. The method can avoid the trouble due to different singularities in the original and transformed systems, and hence can obviate the possible development of spurious singularities in the transformation at low temperatures. The two-dimensional triangular Ising model is treated with numerical results comparable with those obtained by the cluster treatment of Niemeijer and van Leeuwen who used more and larger cluster types than those we introduce.

  13. CriticalEd

    DEFF Research Database (Denmark)

    Kjellberg, Caspar Mølholt; Meredith, David

    2014-01-01

    The best text method is commonly applied among music scholars engaged in producing critical editions. In this method, a comment list is compiled, consisting of variant readings and editorial emendations. This list is maintained by inserting the comments into a document as the changes are made....... Since the comments are not input sequentially, with regard to position, but in arbitrary order, this list must be sorted by copy/pasting the rows into place—an error-prone and time-consuming process. Scholars who produce critical editions typically use off-the-shelf music notation software...... such as Sibelius or Finale. It was hypothesized that it would be possible to develop a Sibelius plug-in, written in Manuscript 6, that would improve the critical editing work flow, but it was found that the capabilities of this scripting language were insufficient. Instead, a 3-part system was designed and built...

  14. 25 CFR 547.10 - What are the minimum standards for Class II gaming system critical events?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false What are the minimum standards for Class II gaming system critical events? 547.10 Section 547.10 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE... GAMES § 547.10 What are the minimum standards for Class II gaming system critical events? This section...

  15. Critical review of LEED system for rating sustainability of architecture of commercial interiors

    Directory of Open Access Journals (Sweden)

    Stevanović Sanja

    2010-01-01

    Full Text Available The LEED rating system for sustainability of architecture has gained large marketing potential in USA and became one of main ways American builders are attacking ecological challenges. In this paper the LEED rating system for commercial interiors is critically reviewed, pointing out its positive - focus on integrated design process - and negative impacts - low thresholds for highest ratings and tendency to gain LEED rating with projects that hardly pass the thresholds, largely neglecting the principles of energy efficiency. Based on a few prominent LEED platinum examples, the beginnings of a LEED style of designing interiors in historical landmark buildings are pointed out as well.

  16. [Incorporation of the Hazard Analysis and Critical Control Point system (HACCP) in food legislation].

    Science.gov (United States)

    Castellanos Rey, Liliana C; Villamil Jiménez, Luis C; Romero Prada, Jaime R

    2004-01-01

    The Hazard Analysis and Critical Control Point system (HACCP), recommended by different international organizations as the Codex Alimentarius Commission, the World Trade Organization (WTO), the International Office of Epizootics (OIE) and the International Convention for Vegetables Protection (ICPV) amongst others, contributes to ensuring the innocuity of food along the agro-alimentary chain and requires of Good Manufacturing Practices (GMP) for its implementation, GMP's which are legislated in most countries. Since 1997, Colombia has set rules and legislation for application of HACCP system in agreement with international standards. This paper discusses the potential and difficulties of the legislation enforcement and suggests some policy implications towards food safety.

  17. Choice of optical system is critical for the security of double random phase encryption systems

    Science.gov (United States)

    Muniraj, Inbarasan; Guo, Changliang; Malallah, Ra'ed; Cassidy, Derek; Zhao, Liang; Ryle, James P.; Healy, John J.; Sheridan, John T.

    2017-06-01

    The linear canonical transform (LCT) is used in modeling a coherent light-field propagation through first-order optical systems. Recently, a generic optical system, known as the quadratic phase encoding system (QPES), for encrypting a two-dimensional image has been reported. In such systems, two random phase keys and the individual LCT parameters (α,β,γ) serve as secret keys of the cryptosystem. It is important that such encryption systems also satisfy some dynamic security properties. We, therefore, examine such systems using two cryptographic evaluation methods, the avalanche effect and bit independence criterion, which indicate the degree of security of the cryptographic algorithms using QPES. We compared our simulation results with the conventional Fourier and the Fresnel transform-based double random phase encryption (DRPE) systems. The results show that the LCT-based DRPE has an excellent avalanche and bit independence characteristics compared to the conventional Fourier and Fresnel-based encryption systems.

  18. Benchmark critical experiments on low-enriched uranium oxide systems with H/U = 0. 77

    Energy Technology Data Exchange (ETDEWEB)

    Tuck, G; Oh, I

    1979-08-01

    Ten benchmark experiments were performed at the Critical Mass Laboratory at Rockwell International's Rocky Flats Plant, Golden, Colorado, for the US Nuclear Regulatory Commission. They provide accurate criticality data for low-enriched damp uranium oxide (U/sub 3/O/sub 8/) systems. The core studied consisted of 152 mm cubical aluminum cans containing an average of 15,129 g of low-enriched (4.46% /sup 235/U) uranium oxide compacted to a density of 4.68 g/cm/sup 3/ and with an H/U atomic ratio of 0.77. One hundred twenty five (125) of these cans were arranged in an approx. 770 mm cubical array. Since the oxide alone cannot be made critical in an array of this size, an enriched (approx. 93% /sup 235/U) metal or solution driver was used to achieve criticality. Measurements are reported for systems having the least practical reflection and for systems reflected by approx. 254-mm-thick concrete or plastic. Under the three reflection conditions, the mass of the uranium metal driver ranged from 29.87 kg to 33.54 kg for an oxide core of 1864.6 kg. For an oxide core of 1824.9 kg, the weight of the high concentration (351.2 kg U/m/sup 3/) solution driver varied from 14.07 kg to 16.14 kg, and the weight of the low concentration (86.4 kg U/m/sup 3/) solution driver from 12.4 kg to 14.0 kg.

  19. Product Engineering Class in the Software Safety Risk Taxonomy for Building Safety-Critical Systems

    Science.gov (United States)

    Hill, Janice; Victor, Daniel

    2008-01-01

    When software safety requirements are imposed on legacy safety-critical systems, retrospective safety cases need to be formulated as part of recertifying the systems for further use and risks must be documented and managed to give confidence for reusing the systems. The SEJ Software Development Risk Taxonomy [4] focuses on general software development issues. It does not, however, cover all the safety risks. The Software Safety Risk Taxonomy [8] was developed which provides a construct for eliciting and categorizing software safety risks in a straightforward manner. In this paper, we present extended work on the taxonomy for safety that incorporates the additional issues inherent in the development and maintenance of safety-critical systems with software. An instrument called a Software Safety Risk Taxonomy Based Questionnaire (TBQ) is generated containing questions addressing each safety attribute in the Software Safety Risk Taxonomy. Software safety risks are surfaced using the new TBQ and then analyzed. In this paper we give the definitions for the specialized Product Engineering Class within the Software Safety Risk Taxonomy. At the end of the paper, we present the tool known as the 'Legacy Systems Risk Database Tool' that is used to collect and analyze the data required to show traceability to a particular safety standard

  20. Seasonal Thermal-Energy Storage: A Critical Review on BTES Systems, Modeling, and System Design for Higher System Efficiency

    Directory of Open Access Journals (Sweden)

    Michael Lanahan

    2017-05-01

    Full Text Available Buildings consume approximately ¾ of the total electricity generated in the United States, contributing significantly to fossil fuel emissions. Sustainable and renewable energy production can reduce fossil fuel use, but necessitates storage for energy reliability in order to compensate for the intermittency of renewable energy generation. Energy storage is critical for success in developing a sustainable energy grid because it facilitates higher renewable energy penetration by mitigating the gap between energy generation and demand. This review analyzes recent case studies—numerical and field experiments—seen by borehole thermal energy storage (BTES in space heating and domestic hot water capacities, coupled with solar thermal energy. System design, model development, and working principle(s are the primary focus of this analysis. A synopsis of the current efforts to effectively model BTES is presented as well. The literature review reveals that: (1 energy storage is most effective when diurnal and seasonal storage are used in conjunction; (2 no established link exists between BTES computational fluid dynamics (CFD models integrated with whole building energy analysis tools, rather than parameter-fit component models; (3 BTES has less geographical limitations than Aquifer Thermal Energy Storage (ATES and lower installation cost scale than hot water tanks and (4 BTES is more often used for heating than for cooling applications.

  1. The under-critical reactors physics for the hybrid systems; La physique des reacteurs sous-critiques des systemes hybrides

    Energy Technology Data Exchange (ETDEWEB)

    Schapira, J.P. [Institut de Physique Nucleaire, IN2P3/CNRS 91 - Orsay (France); Vergnes, J. [Electricite de France, EDF, Direction des Etudes et Recherches, 75 - Paris (France); Zaetta, A. [CEA/Saclay, Direction des Reacteurs Nucleaires, DRN, 91 - Gif-sur-Yvette (France)] [and others

    1998-03-12

    This day, organized by the SFEN, took place at Paris the 12 march 1998. Nine papers were presented. They take stock on the hybrid systems and more specifically the under-critical reactors. One of the major current preoccupation of nuclear industry is the problems of the increase of radioactive wastes produced in the plants and the destruction of the present stocks. To solve these problems a solution is the utilisation of hybrid systems: the coupling of a particle acceleration to an under-critical reactor. Historical aspects, advantages and performances of such hybrid reactors are presented in general papers. More technical papers are devoted to the spallation, the MUSE and the TARC experiments. (A.L.B.)

  2. Towards the Verification of Safety-critical Autonomous Systems in Dynamic Environments

    Directory of Open Access Journals (Sweden)

    Adina Aniculaesei

    2016-12-01

    Full Text Available There is an increasing necessity to deploy autonomous systems in highly heterogeneous, dynamic environments, e.g. service robots in hospitals or autonomous cars on highways. Due to the uncertainty in these environments, the verification results obtained with respect to the system and environment models at design-time might not be transferable to the system behavior at run time. For autonomous systems operating in dynamic environments, safety of motion and collision avoidance are critical requirements. With regard to these requirements, Macek et al. [6] define the passive safety property, which requires that no collision can occur while the autonomous system is moving. To verify this property, we adopt a two phase process which combines static verification methods, used at design time, with dynamic ones, used at run time. In the design phase, we exploit UPPAAL to formalize the autonomous system and its environment as timed automata and the safety property as TCTL formula and to verify the correctness of these models with respect to this property. For the runtime phase, we build a monitor to check whether the assumptions made at design time are also correct at run time. If the current system observations of the environment do not correspond to the initial system assumptions, the monitor sends feedback to the system and the system enters a passive safe state.

  3. Formulation of a strategy for monitoring control integrity in critical digital control systems

    Science.gov (United States)

    Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

    1991-01-01

    Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

  4. Critical Infrastructure Vulnerability to Spatially Localized Failures with Applications to Chinese Railway System.

    Science.gov (United States)

    Ouyang, Min; Tian, Hui; Wang, Zhenghua; Hong, Liu; Mao, Zijun

    2017-01-17

    This article studies a general type of initiating events in critical infrastructures, called spatially localized failures (SLFs), which are defined as the failure of a set of infrastructure components distributed in a spatially localized area due to damage sustained, while other components outside the area do not directly fail. These failures can be regarded as a special type of intentional attack, such as bomb or explosive assault, or a generalized modeling of the impact of localized natural hazards on large-scale systems. This article introduces three SLFs models: node centered SLFs, district-based SLFs, and circle-shaped SLFs, and proposes a SLFs-induced vulnerability analysis method from three aspects: identification of critical locations, comparisons of infrastructure vulnerability to random failures, topologically localized failures and SLFs, and quantification of infrastructure information value. The proposed SLFs-induced vulnerability analysis method is finally applied to the Chinese railway system and can be also easily adapted to analyze other critical infrastructures for valuable protection suggestions.

  5. Some mathematical aspects of the scaling limit of critical two-dimensional systems

    Indian Academy of Sciences (India)

    Wendelin Werner

    2005-05-01

    It has been observed long ago that many systems from statistical physics behave randomly on macroscopic level at their critical temperature. In two dimensions, these phenomena have been classified by theoretical physicists thanks to conformal field theory, that led to the derivation of the exact value of various critical exponents that describe their behavior near the critical temperature. In the last couple of years, combining ideas of complex analysis and probability theory, mathematicians have constructed and studied a family of random fractals (called `Schramm–Loewner evolutions' or SLE) that describe the only possible conformally invariant limits of the interfaces for these models. This gives a concrete construction of these random systems, puts various predictions on a rigorous footing, and leads to further understanding of their behavior. The goal of this paper is to survey some of these recent mathematical developments, and to describe a couple of basic underlying ideas. We will also briefly describe some very recent and ongoing developments relating SLE, Brownian loop soups and conformal field theory.

  6. Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, R.E.

    1996-09-30

    A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution`s concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the `Poisoned Tube Tank` because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service.

  7. Codevelopment of conceptual understanding and critical attitude: toward a systemic analysis of the survival blanket

    Science.gov (United States)

    Viennot, Laurence; Décamp, Nicolas

    2016-01-01

    One key objective of physics teaching is the promotion of conceptual understanding. Additionally, the critical faculty is universally seen as a central quality to be developed in students. In recent years, however, teaching objectives have placed stronger emphasis on skills than on concepts, and there is a risk that conceptual structuring may be disregarded. The question therefore arises as to whether it is possible for students to develop a critical stance without a conceptual basis, leading in turn to the issue of possible links between the development of conceptual understanding and critical attitude. In an in-depth study to address these questions, the participants were seven prospective physics and chemistry teachers. The methodology included a ‘teaching interview’, designed to observe participants’ responses to limited explanations of a given phenomenon and their ensuing intellectual satisfaction or frustration. The explanatory task related to the physics of how a survival blanket works, requiring a full and appropriate system analysis of the blanket. The analysis identified five recurrent lines of reasoning and linked these to judgments of adequacy of explanation, based on metacognitive/affective (MCA) factors, intellectual (dis)satisfaction and critical stance. Recurrent themes and MCA factors were used to map the intellectual dynamics that emerged during the interview process. Participants’ critical attitude was observed to develop in strong interaction with their comprehension of the topic. The results suggest that most students need to reach a certain level of conceptual mastery before they can begin to question an oversimplified explanation, although one student’s replies show that a different intellectual dynamics is also possible. The paper ends with a discussion of the implications of these findings for future research and for decisions concerning teaching objectives and the design of learning environments.

  8. A Leveled Dag Critical Task Firstschedule Algorithm in Distributed Computing Systems

    Directory of Open Access Journals (Sweden)

    Amal EL-NATTAT

    2016-01-01

    Full Text Available In distributed computing environment, efficient task scheduling is essential to obtain high performance. A vital role of designing and development of task scheduling algorithms is to achieve better makes pan. Several task scheduling algorithms have been developed for homogeneous and heterogeneous distributed computing systems. In this paper, a new static task scheduling algorithm is proposed namely; Leveled DAG Critical Task First (LDCTF that optimizes the performance of Leveled DAG Prioritized Task (LDPT algorithm to efficiently schedule tasks on homogeneous distributed computing systems. LDPT was compared to B-level algorithm which is the most famous algorithm in homogeneous distributed systems and it provided better results. LDCTF is a list based scheduling algorithm which depends on sorting tasks into a list according to their priority then scheduling one by one on the suitable processor. LDCTF aims to improve the performance of the system by minimizing the schedule length than LDPT and B-level algorithms.

  9. Possible Self-Organised Criticality and Dynamical Clustering of Traffic flow in Open Systems

    CERN Document Server

    Larraga, M E; Mehta, A; Mehta, Anita

    1999-01-01

    We focus in this work on the study of traffic in open systems using a modified version of an existing cellular automaton model. We demonstrate that the open system is rather different from the closed system in its 'choice' of a unique steady-state density and velocity distribution, independently of the initial conditions, reminiscent of self-organised criticality. Quantities of interest such as average densities and velocities of cars, exhibit phase transitions between free flow and the jammed state, as a function of the braking probability R in a way that is very different from closed systems. Velocity correlation functions show that the concept of a dynamical cluster, introduced earlier in the context of granular flow is also relevant for traffic flow models.

  10. Critical Clearing Time and Wind Power in Small Isolated Power Systems Considering Inertia Emulation

    Directory of Open Access Journals (Sweden)

    Elías Jesús Medina-Domínguez

    2015-11-01

    Full Text Available The stability and security of small and isolated power systems can be compromised when large amounts of wind power enter them. Wind power integration depends on such factors as power generation capacity, conventional generation technology or grid topology. Another issue that can be considered is critical clearing time (CCT. In this paper, wind power and CCT are studied in a small isolated power system. Two types of wind turbines are considered: a squirrel cage induction generator (SCIG and a full converter. Moreover, the full converter wind turbine’s inertia emulation capability is considered, and its impact on CCT is discussed. Voltage is taken into account because of its importance in power systems of this kind. The study focuses on the small, isolated Lanzarote-Fuerteventura power system, which is expected to be in operation by 2020.

  11. Offshore Variability in Critical Weather Conditions in Large-Scale Wind Based Danish Power System

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Sørensen, Poul Ejnar

    2013-01-01

    Offshore wind power has a significant development potential, especially in North Europe. The geographical concentration of offshore wind power leads to increased variability and in the case of critical weather conditions it may lead to sudden and considerable loss of production. In this context......, the chances of losing several GW of wind power due to critical weather conditions in a very short time period could potentially jeopardize the whole system’s reliability and stability. Forecasting such events is not trivial and the results so far are not encouraging. When assessing the impact...... of the variability for the 2020 Danish power system, one can see that in the worst case, up to 1500 MW of power can be lost in 30 minutes. We present results showing how this issue is partially solved by the new High Wind Storm Controller presented by Siemens in the TWENTIES project....

  12. Self-assembly in chains, rings, and branches: a single component system with two critical points.

    Science.gov (United States)

    Rovigatti, Lorenzo; Tavares, José Maria; Sciortino, Francesco

    2013-10-18

    We study the interplay between phase separation and self-assembly in chains, rings, and branched structures in a model of particles with dissimilar patches. We extend Wertheim's first order perturbation theory to include the effects of ring formation and to theoretically investigate the thermodynamics of the model. We find a peculiar shape for the vapor-liquid coexistence, featuring reentrant behavior in both phases and two critical points, despite the single-component nature of the system. The emergence of the lower critical point is caused by the self-assembly of rings taking place in the vapor, generating a phase with lower energy and lower entropy than the liquid. Monte Carlo simulations of the same model fully support these unconventional theoretical predictions.

  13. Digital System Reliability Test for the Evaluation of safety Critical Software of Digital Reactor Protection System

    Directory of Open Access Journals (Sweden)

    Hyun-Kook Shin

    2006-08-01

    Full Text Available A new Digital Reactor Protection System (DRPS based on VME bus Single Board Computer has been developed by KOPEC to prevent software Common Mode Failure(CMF inside digital system. The new DRPS has been proved to be an effective digital safety system to prevent CMF by Defense-in-Depth and Diversity (DID&D analysis. However, for practical use in Nuclear Power Plants, the performance test and the reliability test are essential for the digital system qualification. In this study, a single channel of DRPS prototype has been manufactured for the evaluation of DRPS capabilities. The integrated functional tests are performed and the system reliability is analyzed and tested. The results of reliability test show that the application software of DRPS has a very high reliability compared with the analog reactor protection systems.

  14. CRITICAL SUCCESS FACTORS FOR IMPLEMENTING AN ERP SYSTEM WITHIN UNIVERSITY CONTEXT: CONCEPTS AND LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    Ashwaq AlQashami

    2015-11-01

    Full Text Available Nowadays, Information Technology (IT plays an important role in efficiency and effectiveness of the organizational performance. As an IT application, Enterprise Resource Planning (ERP systems is considered one of the most important IT applications because it enables the organizations to connect and interact with its administrative units in order to manage data and organize internal procedures. Many institutions use ERP systems, most notably Higher Education Institutions (HEIs. However, many projects fail or exceed scheduling and budget constraints; the rate of failure in HEIs sector is higher than in other sectors. With HEIs’ recent movement to implement ERP systems and the lack of research studies examining successful implementation in HEIs, this paper provides a critical literature review with a special focus on Saudi Arabia. Further, it defines Critical Success Factors (CSFs contributing to the success of ERP implementation in HEIs. This paper is part of a larger research effort aiming to provide guidelines and useful findings that help HEIs to manage the challenges for ERP systems and define CSFs that will help practitioners to implement them in the Saudi context.

  15. Universality of finite-size corrections to geometrical entanglement in one-dimensional quantum critical systems

    Science.gov (United States)

    Liu, Xi-Jing; Hu, Bing-Quan; Cho, Sam Young; Zhou, Huan-Qiang; Shi, Qian-Qian

    2016-10-01

    Recently, the finite-size corrections to the geometrical entanglement per lattice site in the spin-1/2 chain have been numerically shown to scale inversely with system size, and its prefactor b has been suggested to be possibly universal [Q-Q. Shi et al., New J. Phys. 12, 025008 (2010)]. As possible evidence of its universality, the numerical values of the prefactors have been confirmed analytically by using the Affleck-Ludwig boundary entropy with a Neumann boundary condition for a free compactified field [J-M. Stephan et al., Phys. Rev. B 82, 180406(R) (2010)]. However, the Affleck-Ludwig boundary entropy is not unique and does depend on conformally invariant boundary conditions. Here, we show that a unique Affleck-Ludwig boundary entropy corresponding to a finitesize correction to the geometrical entanglement per lattice site exists and show that the ratio of the prefactor b to the corresponding minimum groundstate degeneracy gmin for the Affleck- Ludwig boundary entropy is a constant for any critical region of the spin-1 XXZ system with the single-ion anisotropy, i.e., b/(2 log2 g min ) = -1. Previously studied spin-1/2 systems, including the quantum three-state Potts model, have verified the universal ratio. Hence, the inverse finite-size correction to the geometrical entanglement per lattice site and its prefactor b are universal for one-dimensional critical systems.

  16. Implementation of the Hazard Analysis Critical Control Point (HACCP system to UF white cheese production line

    Directory of Open Access Journals (Sweden)

    Mahmoud El-Hofi

    2010-09-01

    Full Text Available Background. HACCP, or the Hazard Analysis and Critical Control Point System has been recognised as an effective and rational means of assuring food safety from primary production through to final consumption, using a “farm to table” methodology. The application of this preventive oriented approach would give the food producer better control over operation, better manufacturing practices and greater efficiencies, including reduced wastes. Material and methods. The steps taken to put HACCP in place are described and the process was monitored to assess its impact. Assessment of the hygiene quality of the UF white cheese products line before and after HACCP showed an improvement in quality and an overall improvement in the conditions at the company. Results. HACCP was introduced for the in UF White Cheese line at Misr Milk and Food, Mansoura, Egypt, for safe and good quality foods products. All necessary quality control procedures were verified for completeness and to determine if they are being implemented to required standards. A hazard analysis was conducted to identify hazards that may occur in the product cycle, Critical Control Points (CCPs were determined to control the identified hazards. CCP signs were then posted on the factory floor. Critical limits were established at each CCP, corrective actions to be taken when monitoring indicates deviation or loss of control were established. Verification procedures were established to confirm that the HACCP system is working effectively. Documentation concerning all procedures and records was established and integrating HACCP with ISO 9000 under one management system was applied. Conclusions. The HACCP system in this study for UF White Cheese line manufacture is developed step-by-step based on the twelve steps mentioned in the literature review. The prerequisite program was provided to deal with some hazards before the production to simplify the HACCP plan.

  17. A reference model for model-based design of critical infrastructure protection systems

    Science.gov (United States)

    Shin, Young Don; Park, Cheol Young; Lee, Jae-Chon

    2015-05-01

    Today's war field environment is getting versatile as the activities of unconventional wars such as terrorist attacks and cyber-attacks have noticeably increased lately. The damage caused by such unconventional wars has also turned out to be serious particularly if targets are critical infrastructures that are constructed in support of banking and finance, transportation, power, information and communication, government, and so on. The critical infrastructures are usually interconnected to each other and thus are very vulnerable to attack. As such, to ensure the security of critical infrastructures is very important and thus the concept of critical infrastructure protection (CIP) has come. The program to realize the CIP at national level becomes the form of statute in each country. On the other hand, it is also needed to protect each individual critical infrastructure. The objective of this paper is to study on an effort to do so, which can be called the CIP system (CIPS). There could be a variety of ways to design CIPS's. Instead of considering the design of each individual CIPS, a reference model-based approach is taken in this paper. The reference model represents the design of all the CIPS's that have many design elements in common. In addition, the development of the reference model is also carried out using a variety of model diagrams. The modeling language used therein is the systems modeling language (SysML), which was developed and is managed by Object Management Group (OMG) and a de facto standard. Using SysML, the structure and operational concept of the reference model are designed to fulfil the goal of CIPS's, resulting in the block definition and activity diagrams. As a case study, the operational scenario of the nuclear power plant while being attacked by terrorists is studied using the reference model. The effectiveness of the results is also analyzed using multiple analysis models. It is thus expected that the approach taken here has some merits

  18. The hazard analysis and critical control point system in food safety.

    Science.gov (United States)

    Herrera, Anavella Gaitan

    2004-01-01

    The Hazard Analysis and Critical Control Point (HACCP) system is a preventive method of ensuring food safety. Its objectives are the identification of consumer safety hazards that can occur in the production line and the establishment of a control process to guarantee a safer product for the consumer; it is based on the identification of potential hazards to food safety and on measures aimed at preventing these hazards. HACCP is the system of choice in the management of food safety. The principles of HACCP are applicable to all phases of food production, including basic husbandry practices, food preparation and handling, food processing, food service, distribution systems, and consumer handling and use. The HACCP system is involved in every aspect of food safety production (according to the UN Food and Agriculture Organization [FAO] and the International Commission on Microbiological Specifications for Foods [ICMSF]). The most basic concept underlying the HACCP system is that of prevention rather than inspection. The control of processes and conditions comprises the critical control point (CCP) element. HACCP is simply a methodical, flexible, and systematic application of the appropriate science and technology for planning, controlling, and documenting the safe production of foods. The successful application of HACCP requires the full commitment and involvement of management and the workforce, using a multidisciplinary approach that should include, as appropriate, expertise in agronomy, veterinary health, microbiology, public health, food technology, environmental health, chemistry, engineering, and so on according to the particular situation. Application of the HACCP system is compatible with the implementation of total quality management (TQM) systems such as the ISO 9000 series.

  19. Addressing critical issues in the development of an Oncology Information System.

    Science.gov (United States)

    Urda, D; Ribelles, N; Subirats, J L; Franco, L; Alba, E; Jerez, J M

    2013-05-01

    This paper presents the experience on the design and implementation of a user-centered Oncology Information System developed for the Medical Oncology Department at the "Hospital Universitario Virgen de la Victoria", in Málaga, Spain. The project focused on the aspects considered in the literature as critical factors for a successful deployment and usage of a health information system. System usability, adequate technology, integration of clinical routines, real-time statistical analysis of data, information confidentiality and standard protocol-based external interconnection were the key aspects considered. The developed system is based on a web application with a modular and layered architecture accounting for usability, ease of maintenance and further system development. Evaluation of system usability was carried at three and fifteen months after system deployment to analyze the advantages/disadvantages experienced by the end-users. A thorough prior analysis of clinical activities and workflows, the use of the adequate technology, and the availability of data analysis tools will almost guarantee success in the deployment of an Oncology Information System. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  20. Critical interactions between the Global Fund-supported HIV programs and the health system in Ghana

    DEFF Research Database (Denmark)

    Atun, Rifat; Pothapregada, Sai Kumar; Kwansah, Janet

    2011-01-01

    The support of global health initiatives in recipient countries has been vigorously debated. Critics are concerned that disease-specific programs may be creating vertical and parallel service delivery structures that to some extent undermine health systems. This case study of Ghana aimed to explore...... care delivery. Ghana has benefited from US $175 million of approved Global Fund support to address the HIV epidemic, accounting for almost 85% of the National AIDS Control Program budget. Investments in infrastructure, human resources, and commodities have enabled HIV interventions to increase...... of the strengths and weaknesses of the relationship between Global Fund-supported activities and the health system and to identify positive synergies and unintended consequences of integration. Ghana has a well-functioning sector-wide approach to financing its health system, with a strong emphasis on integrated...

  1. Critical evaluation and thermodynamic optimization of the U-Pb and U-Sb binary systems

    Science.gov (United States)

    Wang, Jian; Jin, Liling; Chen, Chuchu; Rao, Weifeng; Wang, Cuiping; Liu, Xingjun

    2016-11-01

    A complete literature review, critical evaluation and thermodynamic optimization of the phase diagrams and thermodynamic properties of U-Pb and U-Sb binary systems are presented. The CALculation of PHAse Diagrams (CALPHAD) method was used for the thermodynamic optimization, the results of which can reproduce all available reliable experimental phase equilibria and thermodynamic data. The modified quasi-chemical model in the pair approximation (MQMPA) was used for modeling the liquid solution. The Gibbs energies of all terminal solid solutions and intermetallic compounds were described by the compound energy formalism (CEF) model. All reliable experimental data of the U-Pb and U-Sb systems have been reproduced. A self-consistent thermodynamic database has been constructed for these binary systems; this database can be used in liquid-metal fuel reactor (LMFR) research.

  2. Display system analysis with critical polarization elements in a non-sequential ray tracing environment

    Science.gov (United States)

    Herlocker, J. A.; Jiang, J.; Garcia, K. J.

    2008-08-01

    Common digital display systems have evolved into sophisticated optical devices. The rapid market growth in liquid crystal displays makes the simulation of full systems attractive, promoting virtual prototyping with decreased development times and improved manufacturability. Realistic simulation using commercial non-sequential ray tracing tools has been instrumental in this process, but the need to accurately model polarization devices has become critical in many designs. As display systems seek more efficient use of light and more accurate color representation, the proper simulation of polarization devices with large acceptance angles is essential. This paper examines non-uniform polarization effects in the simulation of modern display devices using realistic polarizer and retarder models in the ASAP® non-sequential ray-tracing environment.

  3. Lasershot(sm) marking system: high-volume labeling for safety-critical parts

    Energy Technology Data Exchange (ETDEWEB)

    Dane, C B; Hackel, L; Honig, J; Halpin, J; Chen, H-L; Mendieta, F; Harris, F; Lane, L; Daly, J; Harrison, J

    2001-02-16

    The Lasershot Marking System uses laser pulses to safely and permanently impress identification markings on metal components. This process does not remove material or change surface chemistry and actually increases the marked area's resistance to fatigue and corrosion failure. Lasershot marking is ideally suited for marking parts used in situations where safety is critical--from hip-joint replacements to commercial airliner components. The minimum size of the mark is limited only by the resolution of the reading system, allowing manufacturers to mark parts which, up to now, have been too small to label with mechanical peening techniques. The high resolution of the Lasershot marks makes them difficult to reproduce, providing a solution to the ongoing problem of inferior, counterfeited parts. The high marking rate of up to six marks per second makes this system practical and cost-effective for marking high-volume components.

  4. Stochastic Oscillation in Self-Organized Critical States of Small Systems: Sensitive Resting State in Neural Systems

    Science.gov (United States)

    Wang, Sheng-Jun; Ouyang, Guang; Guang, Jing; Zhang, Mingsha; Wong, K. Y. Michael; Zhou, Changsong

    2016-01-01

    Self-organized critical states (SOCs) and stochastic oscillations (SOs) are simultaneously observed in neural systems, which appears to be theoretically contradictory since SOCs are characterized by scale-free avalanche sizes but oscillations indicate typical scales. Here, we show that SOs can emerge in SOCs of small size systems due to temporal correlation between large avalanches at the finite-size cutoff, resulting from the accumulation-release process in SOCs. In contrast, the critical branching process without accumulation-release dynamics cannot exhibit oscillations. The reconciliation of SOCs and SOs is demonstrated both in the sandpile model and robustly in biologically plausible neuronal networks. The oscillations can be suppressed if external inputs eliminate the prominent slow accumulation process, providing a potential explanation of the widely studied Berger effect or event-related desynchronization in neural response. The features of neural oscillations and suppression are confirmed during task processing in monkey eye-movement experiments. Our results suggest that finite-size, columnar neural circuits may play an important role in generating neural oscillations around the critical states, potentially enabling functional advantages of both SOCs and oscillations for sensitive response to transient stimuli.

  5. Students' Learning Behavior, Motivation and Critical Thinking in Learning Management Systems

    Directory of Open Access Journals (Sweden)

    Saovapa Wichadee

    2014-07-01

    Full Text Available Computer mediated communication (CMC offers new opportunities for learners to create communities of inquiry that allow for more active learning. This paper reports on the use of a Learning Management System (LMS as a tool to facilitate students’ writing and critical thinking skills. The primary data for the study came from students’ online learning records and from discussion forum postings in the LMS. It was found that students’ motivation to learn was at a high level. Most importantly, student motivation was positively correlated with their learning behavior. Although male and female students did not differ in their motivation and learning behavior, messages in the writing forum indicated that female students had higher critical thinking skills than male students. “Explaining” messages appeared the most often, while “interpreting” messages appeared the least. The process of text-based online discussion in the forum had the potential to enhance the students’ writing skills, encourage their critical thinking, and help them write more systematically. The practical implications of these findings are discussed.

  6. Critical Success Factors for Integrated Library System Implementation in Academic Libraries: A Qualitative Study

    Directory of Open Access Journals (Sweden)

    Shea-Tinn Yeh

    2016-09-01

    Full Text Available Integrated library system (ILS supports the entire business operations of an academic library from acquiring and processing library resources to making them available to user communities and preserving them for future use. As libraries’ needs evolve, there is a pressing demand for libraries to migrate from one generation of ILS to the next. This complex migration process is often the single largest investment in both budget and personnel involvement, but its success is by no means guaranteed. We draw upon enterprise resource planning (ERP and critical success factors (CSFs literature to identify the most salient CSFs for ILS migration success through a qualitative study with four cases. We identified that top management involvement, vendor support, user involvement, selection process, project team competence, project management and tracking, interdepartmental communication, data analysis and conversion, user education and training, and user emotion management are the CSFs that determine a migration project success.  Keywords: Integrated library systems, information systems, library automation, critical success factors, and academic libraries.

  7. Ontario Hydro experience in the identification and mitigation of potential failures in safety critical software systems

    Energy Technology Data Exchange (ETDEWEB)

    Huget, R.G.; Viola, M.; Froebel, P.A. [Ontario Hydro, Toronto, Ontario (Canada)

    1995-08-01

    Ontario Hydro has had experience in designing and qualifying safety critical software used in the reactor shutdown systems of its nuclear generating stations. During software design, an analysis of system level hazards and potential hardware failure effects provide input to determining what safeguards will be needed. One form of safeguard, called software self checks, continually monitor the health of the computer on line. The design of self checks usually is a trade off between the amount of computing resources required, the software complexity, and the level of safeguarding provided. As part of the software verification activity, a software hazards analysis is performed, which identifiers any failure modes that could lead to the software causing an unsafe state, and which recommends changes to mitigate that potential. These recommendations may involve a re-structuring of the software to be more resistant to failure, or the introduction of other safeguarding measures. This paper discusses how Ontario Hydro has implemented these aspects of software design and verification into safety critical software used in reactor shutdown systems.

  8. Validation and Verification of Future Integrated Safety-Critical Systems Operating under Off-Nominal Conditions

    Science.gov (United States)

    Belcastro, Christine M.

    2010-01-01

    Loss of control remains one of the largest contributors to aircraft fatal accidents worldwide. Aircraft loss-of-control accidents are highly complex in that they can result from numerous causal and contributing factors acting alone or (more often) in combination. Hence, there is no single intervention strategy to prevent these accidents and reducing them will require a holistic integrated intervention capability. Future onboard integrated system technologies developed for preventing loss of vehicle control accidents must be able to assure safe operation under the associated off-nominal conditions. The transition of these technologies into the commercial fleet will require their extensive validation and verification (V and V) and ultimate certification. The V and V of complex integrated systems poses major nontrivial technical challenges particularly for safety-critical operation under highly off-nominal conditions associated with aircraft loss-of-control events. This paper summarizes the V and V problem and presents a proposed process that could be applied to complex integrated safety-critical systems developed for preventing aircraft loss-of-control accidents. A summary of recent research accomplishments in this effort is also provided.

  9. Regenerative braking strategies, vehicle safety and stability control systems: critical use-case proposals

    Science.gov (United States)

    Oleksowicz, Selim A.; Burnham, Keith J.; Southgate, Adam; McCoy, Chris; Waite, Gary; Hardwick, Graham; Harrington, Cian; McMurran, Ross

    2013-05-01

    The sustainable development of vehicle propulsion systems that have mainly focused on reduction of fuel consumption (i.e. CO2 emission) has led, not only to the development of systems connected with combustion processes but also to legislation and testing procedures. In recent years, the low carbon policy has made hybrid vehicles and fully electric vehicles (H/EVs) popular. The main virtue of these propulsion systems is their ability to restore some of the expended energy from kinetic movement, e.g. the braking process. Consequently new research and testing methods for H/EVs are currently being developed. This especially concerns the critical 'use-cases' for functionality tests within dynamic events for both virtual simulations, as well as real-time road tests. The use-case for conventional vehicles for numerical simulations and road tests are well established. However, the wide variety of tests and their great number (close to a thousand) creates a need for selection, in the first place, and the creation of critical use-cases suitable for testing H/EVs in both virtual and real-world environments. It is known that a marginal improvement in the regenerative braking ratio can significantly improve the vehicle range and, therefore, the economic cost of its operation. In modern vehicles, vehicle dynamics control systems play the principal role in safety, comfort and economic operation. Unfortunately, however, the existing standard road test scenarios are insufficient for H/EVs. Sector knowledge suggests that there are currently no agreed tests scenarios to fully investigate the effects of brake blending between conventional and regenerative braking as well as the regenerative braking interaction with active driving safety systems (ADSS). The paper presents seven manoeuvres, which are considered to be suitable and highly informative for the development and examination of H/EVs with regenerative braking capability. The critical manoeuvres presented are considered to be

  10. Degree of Schedulability of Mixed-Criticality Real-time Systems with Probabilistic Sporadic Tasks

    DEFF Research Database (Denmark)

    Boudjadar, Jalil; David, Alexandre; Kim, Jin Hyun

    2014-01-01

    We present the concept of degree of schedulability for mixed-criticality scheduling systems. This concept is given in terms of the two factors 1) Percentage of Missed Deadlines (PoMD), and 2) Degradation of the Quality of Service (DoQoS). The novel aspect is that we consider task arrival patterns...... that follow user-defined continuous probability distributions. We determine the degree of schedulability of a single scheduling component which can contain both periodic and sporadic tasks using statistical model checking in the form of UPPAAL SMC. We support uniform, exponential, Gaussian and any user......-defined probability distribution....

  11. Holistic Approach for Critical System Security: Flooding Prevention and Malicious Packet Stopping

    CERN Document Server

    Alhabeeb, M A; Le, P D

    2010-01-01

    Denial of service attacks (DoS) can cause significant financial damages. Flooding and Malicious packets are two kinds of DoS attacks. This paper presents a new security approach which stops malicious packets and prevents flooding in the critical systems. New concepts of packet stamp a dynamic-multi-communication-point mechanism has been identified for this proposed approach to make the prevention of flooding attacks easier and the performing of malicious packet attacks harder. In addition, dynamic key encryption technique has been adapted as a part of the proposed approach to enhance its functionality.

  12. Using the tax system to promote physical activity: critical analysis of Canadian initiatives.

    Science.gov (United States)

    von Tigerstrom, Barbara; Larre, Tamara; Sauder, Joanne

    2011-08-01

    In Canada, tax incentives have been recently introduced to promote physical activity and reduce rates of obesity. The most prominent of these is the federal government's Children's Fitness Tax Credit, which came into effect in 2007. We critically assess the potential benefits and limitations of using tax measures to promote physical activity. Careful design could make these measures more effective, but any tax-based measures have inherent limitations, and the costs of such programs are substantial. Therefore, it is important to consider whether public funds are better spent on other strategies that could instead provide direct public funding to address environmental and systemic factors.

  13. Accelerator-driven sub-critical reactor system (ADS) for nuclear energy generation

    Indian Academy of Sciences (India)

    S S Kapoor

    2002-12-01

    In this talk we present an overview of accelerator-driven sub-critical reactor systems (ADS), and bring out their attractive features for the elimination of troublesome long-lived components of the spent fuel, as well as for nuclear energy generation utilizing thorium as fuel. In India, there is an interest in the programmes of development of high-energy and high-current accelerators due to the potential of ADS in utilizing the vast resources of thorium in the country for nuclear power generation. The accelerator related activities planned in this direction will be outlined.

  14. Fluctuation limit theorems for age-dependent critical binary branching systems

    Directory of Open Access Journals (Sweden)

    Murillo-Salas Antonio

    2011-03-01

    Full Text Available We consider an age-dependent branching particle system in ℝd, where the particles are subject to α-stable migration (0 < α ≤ 2, critical binary branching, and general (non-arithmetic lifetimes distribution. The population starts off from a Poisson random field in ℝd with Lebesgue intensity. We prove functional central limit theorems and strong laws of large numbers under two rescalings: high particle density, and a space-time rescaling that preserves the migration distribution. Properties of the limit processes such as Markov property, almost sure continuity of paths and generalized Langevin equation, are also investigated.

  15. Memory controllers for mixed-time-criticality systems architectures, methodologies and trade-offs

    CERN Document Server

    Goossens, Sven; Akesson, Benny; Goossens, Kees

    2016-01-01

    This book discusses the design and performance analysis of SDRAM controllers that cater to both real-time and best-effort applications, i.e. mixed-time-criticality memory controllers. The authors describe the state of the art, and then focus on an architecture template for reconfigurable memory controllers that addresses effectively the quickly evolving set of SDRAM standards, in terms of worst-case timing and power analysis, as well as implementation. A prototype implementation of the controller in SystemC and synthesizable VHDL for an FPGA development board are used as a proof of concept of the architecture template.

  16. Security-Aware Periodic-Write Scheduling for Mission-Critical Embedded Storage System

    Institute of Scientific and Technical Information of China (English)

    Wei Jiang; Guang-Ze Xiong; Zheng-Wei Chang; Xu-Yang Ding; Nan Sang

    2009-01-01

    High quality of security and guaranteed real-time requirements are two key goals of mission- critical embedded storage systems. But most existing real-time disk scheduling algorithms do not consider improving security performance of disk requests. A security-aware periodic-write (SAPW) scheduling algorithm is proposed to judiciously select appropriate security level for each disk request to maximize security value of N periodic disk users, while without sacrificing timing constraint of each user. Simulation results show the significant effectiveness of SAPW algorithm, and the average security improve- ment is up to 223.6% over other three algorithms.

  17. Critical Infrastructure Modeling: An Approach to Characterizing Interdependencies of Complex Networks & Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Walsh; Shane Cherry; Lyle Roybal

    2009-05-01

    Critical infrastructure control systems face many challenges entering the 21st century, including natural disasters, cyber attacks, and terrorist attacks. Revolutionary change is required to solve many existing issues, including gaining greater situational awareness and resiliency through embedding modeling and advanced control algorithms in smart sensors and control devices instead of in a central controller. To support design, testing, and component analysis, a flexible simulation and modeling capability is needed. Researchers at Idaho National Laboratory are developing and evaluating such a capability through their CIPRsim modeling and simulation framework.

  18. Comparison of critical dimension measurements of a mask inspection system with a CD-SEM

    Science.gov (United States)

    Heumann, Jan P.; Ullrich, Albrecht; Utzny, Clemens S.; Meusemann, Stefan; Kromer, Frank; Whittey, John M.; Garcia, Edgardo; Wagner, Mark; Schmidt, Norbert J.

    2012-11-01

    Critical dimension uniformity (CDU) is an important parameter for photomask and wafer manufacturing. In order to reduce long-range CD variation, compensation techniques for mask writers and scanners have been developed. Both techniques require mask CD measurements with high spatial sampling. Scanning electron microscopes (SEMs), which provide CD measurements at very high precision, cannot in practice provide the required spatial sampling due to their low speed. In contrast mask inspection systems, some of which have the ability to perform optical CD measurements with very high sampling frequencies, are an interesting alternative. In this paper we evaluate the CDU measurement results with those of a CD-SEM.

  19. Discrete Multiwavelet Critical-Sampling Transform-Based OFDM System over Rayleigh Fading Channels

    Directory of Open Access Journals (Sweden)

    Sameer A. Dawood

    2015-01-01

    Full Text Available Discrete multiwavelet critical-sampling transform (DMWCST has been proposed instead of fast Fourier transform (FFT in the realization of the orthogonal frequency division multiplexing (OFDM system. The proposed structure further reduces the level of interference and improves the bandwidth efficiency through the elimination of the cyclic prefix due to the good orthogonality and time-frequency localization properties of the multiwavelet transform. The proposed system was simulated using MATLAB to allow various parameters of the system to be varied and tested. The performance of DMWCST-based OFDM (DMWCST-OFDM was compared with that of the discrete wavelet transform-based OFDM (DWT-OFDM and the traditional FFT-based OFDM (FFT-OFDM over flat fading and frequency-selective fading channels. Results obtained indicate that the performance of the proposed DMWCST-OFDM system achieves significant improvement compared to those of DWT-OFDM and FFT-OFDM systems. DMWCST improves the performance of the OFDM system by a factor of 1.5–2.5 dB and 13–15.5 dB compared with the DWT and FFT, respectively. Therefore the proposed system offers higher data rate in wireless mobile communications.

  20. The ISTIMES project: a new integrated system for monitoring critical transport infrastructures interested by natural hazards

    Science.gov (United States)

    Proto, Monica; Massimo, Bavusi; Francesco, Soldovieri

    2010-05-01

    The research project "Integrated System for Transport Infrastructure surveillance and Monitoring by Electromagnetic Sensing" (ISTIMES), was approved in the 7th Framework Programme, in the Joint Call ICT and Security and started on 1st July 2009. The purpose of ISTIMES project is to design, assess and promote an ICT-based system, exploiting distributed and local sensors, for non-destructive electromagnetic monitoring in order to achieve the critical transport infrastructures more reliable and safe. The transportation sector's components are susceptible to the consequences of natural disasters and can also be attractive as terrorist targets. The sector's size, its physically dispersed and decentralized nature, the many public and private entities involved in its operations, the critical importance of cost considerations, and the inherent requirement of convenient accessibility to its services by all users - make the transportation particularly vulnerable to security and safety threats. As well known, the surface transportation system consists of interconnected infrastructures including highways, transit systems, railroads, airports, waterways, pipelines and ports, and the vehicles, aircraft, and vessels that operate along these networks. Thus, interdependencies exist between transportation and nearly every other sector of the economy and the effective operation of this system is essential to the European economic productivity; therefore, transportation sector protection is of paramount importance since threats to it may impact other industries that rely on it. The system exploits an open network architecture that can accommodate a wide range of sensors, static and mobile, and can be easily scaled up to allow the integration of additional sensors and interfacing with other networks. It relies on heterogeneous state-of-the-art electromagnetic sensors, enabling a self-organizing, self-healing, ad-hoc networking of terrestrial sensors, supported by specific satellite

  1. Assessment of Proliferation Resistance of Closed Nuclear Fuel Cycle System with Sodium Cooled Fast Reactors Using INPRO Evaluation Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young In; Hahn, Do Hee; Won, Byung Chool; Lee, Dong Uk

    2007-11-15

    Using the INPRO methodology, the proliferation resistance of an innovative nuclear energy system(INS) defined as a closed nuclear fuel cycle system consisting of KALIMER and pyroprocessing, has been assessed. Considering a very early development stage of the INS concept, the PR assessment is carried out based on intrinsic features, if required information and data are not available. The PR assessment of KALIMER and JSFR using the INPRO methodology affirmed that an adequate proliferation resistance has been achieved in both INSs CNFC-SFR, considering the assessor's progress and maturity of design development. KALIMER and JSFR are developed or being developed conforming to the targets and criteria defined for developing Gen IV nuclear reactor system. Based on these assessment results, proliferation resistance and physical protection(PR and PP) of KALIMER and JSFR are evaluated from the viewpoint of requirements for future nuclear fuel cycle system. The envisioned INSs CNFC-SFR rely on active plutonium management based on a closed fuel cycle, in which a fissile material is recycled in an integrated fuel cycle facility within proper safeguards. There is no isolated plutonium in the closed fuel cycle. The material remains continuously in a sequence of highly radioactive matrices within inaccessible facilities. The proliferation resistance assessment should be an ongoing analysis that keeps up with the progress and maturity of the design of Gen IV SFR.

  2. Redundant Flight-Critical Control System Evaluation. Analog and Digital Systems Performance Comparison

    Science.gov (United States)

    1974-10-01

    brandling is utilized, the computer will sequence through algorithms 1 through 64 during even algorithm processing time slots and 65 through 128 during...of one through the system, at approximately 6 rad. This is predictable from the preceding discussion and the recognition that the 10-V input produces

  3. New approaches to provide ride-through for critical loads in electric power distribution systems

    Science.gov (United States)

    Montero-Hernandez, Oscar C.

    2001-07-01

    The extensive use of electronic circuits has enabled modernization, automation, miniaturization, high quality, low cost, and other achievements regarding electric loads in the last decades. However, modern electronic circuits and systems are extremely sensitive to disturbances from the electric power supply. In fact, the rate at which these disturbances happen is considerable as has been documented in recent years. In response to the power quality concerns presented previously, this dissertation is proposing new approaches to provide ride-through for critical loads during voltage disturbances with emphasis on voltage sags. In this dissertation, a new approach based on an AC-DC-AC system is proposed to provide ride-through for critical loads connected in buildings and/or an industrial system. In this approach, a three-phase IGBT inverter with a built in Dc-link voltage regulator is suitably controlled along with static by-pass switches to provide continuous power to critical loads. During a disturbance, the input utility source is disconnected and the power from the inverter is connected to the load. The remaining voltage in the AC supply is converted to DC and compensated before being applied to the inverter and the load. After detecting normal utility conditions, power from the utility is restored to the critical load. In order to achieve an extended ride-through capability a second approach is introduced. In this case, the Dc-link voltage regulator is performed by a DC-DC Buck-Boost converter. This new approach has the capability to mitigate voltage variations below and above the nominal value. In the third approach presented in this dissertation, a three-phase AC to AC boost converter is investigated. This converter provides a boosting action for the utility input voltages, right before they are applied to the load. The proposed Pulse Width Modulation (PWM) control strategy ensures independent control of each phase and compensates for both single-phase or poly

  4. Fostering Critical Thinking in the Geosciences: Combining Geoethics, the Affective Domain, Metacognition, and Systems Thinking

    Science.gov (United States)

    Mogk, D. W.; Geissman, J. W.

    2015-12-01

    There is a compelling need to develop the geoscience workforce of the future to address the "grand challenges" that face humanity. This workforce must have a strong understanding of Earth history, processes and materials and be able to communicate effectively and responsibly to inform public policy and personal and societal actions, particularly with regard to geohazards and natural resources. Curricula to train future geoscientists must be designed to help students develop critical thinking skills across the curriculum, from introductory to senior capstone courses. Students will be challenged in their pre-professional training as geoscientists as they encounter an incomplete geologic record, ambiguity and uncertainty in observed and experimental results, temporal reasoning ("deep time", frequency, recurrence intervals), spatial reasoning (from microns to mountains), and complex system behavior. Four instructional approaches can be combined to address these challenges and help students develop critical thinking skills: 1) Geoethics and ethical decision making includes review and integration of the context/facts of the situation, stakeholders, decision-makers, and possible alternative actions and expected outcomes; 2) The affective domain which encompasses factors such as student motivation to learn, curiosity, fear, attitudes, perceptions, social barriers and values; 3) Metacognition which encourages students to be aware about their own thinking processes, and to develop self-monitoring and self-regulating behaviors; and 4) Systems thinking which requires integrative thinking about the interactions between physical, chemical, biological and human processes, feedback mechanisms and emergent phenomena. Guided inquiry and scaffolded exercises can be used to present increasingly complex situations that require a thorough understanding of geologic principles and processes as applied to issues of societal concern. These approaches are not "owned" by any single course or

  5. Monitoring and Control of Urban Critical Infrastructures: A Novel Approach to System Design and Data Fusion

    Directory of Open Access Journals (Sweden)

    Mario La Manna

    2015-02-01

    Full Text Available The monitoring and control of urban critical infrastructures consists of the protection of assets such as houses, offices, government and private buildings, with low cost, high quality and high dependability. In order to satisfy all these requirements at the same time, the control of a number of assets has to be performed by means of automated systems based on networks of heterogeneous sensors. This new concept idea is based on the use of unmanned operations at each of the many remote assets (each asset is monitored through a network of sensors and a man-in-the-loop automated control in a central site (Operational Center, which performs alarm detection and system management.

  6. Past and present status of runoff harvesting systems in dryland peninsular India: a critical review.

    Science.gov (United States)

    Gunnell, Yanni; Krishnamurthy, Anupama

    2003-06-01

    Many modern agricultural systems are structured around one dominant form of water storage and distribution, usually large reservoirs. In contrast, in peninsular India, small reservoirs (tanks), predominantly supplied by surface runoff as opposed to river canals have for centuries been the trademark of an entire agrarian civilization, with no equivalent elsewhere in the semiarid tropics. This article focuses on the physical and socioeconomic conditions that underlie the success of an indigenous technology which has for centuries exploited the potential for runoff harvesting by i) optimizing water management for agriculture; and ii) minimizing soil loss. Today, siltation of reservoirs, privatization of water resources, and generalized mining of groundwater, pose a threat to the sustainability of these water-harvesting systems. The ongoing transformation of this common resource pool is critically assessed.

  7. Validation of Safety-Critical Systems for Aircraft Loss-of-Control Prevention and Recovery

    Science.gov (United States)

    Belcastro, Christine M.

    2012-01-01

    Validation of technologies developed for loss of control (LOC) prevention and recovery poses significant challenges. Aircraft LOC can result from a wide spectrum of hazards, often occurring in combination, which cannot be fully replicated during evaluation. Technologies developed for LOC prevention and recovery must therefore be effective under a wide variety of hazardous and uncertain conditions, and the validation framework must provide some measure of assurance that the new vehicle safety technologies do no harm (i.e., that they themselves do not introduce new safety risks). This paper summarizes a proposed validation framework for safety-critical systems, provides an overview of validation methods and tools developed by NASA to date within the Vehicle Systems Safety Project, and develops a preliminary set of test scenarios for the validation of technologies for LOC prevention and recovery

  8. On the theory of quantum quenches in near-critical systems

    Science.gov (United States)

    Delfino, Gesualdo; Viti, Jacopo

    2017-02-01

    The theory of quantum quenches in near-critical one-dimensional systems formulated in Delfino (2014 J. Phys. A: Math. Theor. 402001) yields analytic predictions for the dynamics, unveils a qualitative difference between non-interacting and interacting systems, with undamped oscillations of one-point functions occurring only in the latter case, and explains the presence and role of different time scales. Here we examine additional aspects, determining in particular the relaxation value of one-point functions for small quenches. For a class of quenches we relate this value to the scaling dimensions of the operators. We argue that the E 8 spectrum of the Ising chain can be more accessible through a quench than at equilibrium, while for a quench of the plane anisotropy in the XYZ chain we obtain that the one-point function of the quench operator switches from damped to undamped oscillations at Δ =1/2 .

  9. On the theory of quantum quenches in near-critical systems

    CERN Document Server

    Delfino, Gesualdo

    2016-01-01

    The theory of quantum quenches in near-critical one-dimensional systems formulated in [J. Phys. A 47 (2014) 402001] yields analytic predictions for the dynamics, unveils a qualitative difference between non-interacting and interacting systems, with undamped oscillations of one-point functions occurring only in the latter case, and explains the presence of different time scales. Here we examine additional aspects, obtaining in particular the expression for the relaxation value of one-point functions for small quenches. We argue that the $E_8$ spectrum of the Ising chain is more accessible through a quench than at equilibrium, while for a quench of the plane anisotropy in the XYZ chain we obtain that the one-point function of the quench operator switches from damped to undamped oscillations at $\\Delta=1/2$.

  10. A Critical Review of Environmental Management System as a Tool for Sustainability

    DEFF Research Database (Denmark)

    Galamba, Kirsten Ramskov

    2012-01-01

    Purpose: The aim of the article is to make a critical review of the environmental management system as a tool for sustainability in local authorities. Background: As a point of departure sustainability is outlined as an ambivalent term that has been interpreted in a number of ways, which...... is important as the understanding informs the choice of societal response to the ecological crisis. Approach (Theory/Methodology): Action research has been used as the primary methodological approach for the empirical work and the empirical material has been analysed with respect to reflections...... on environmental management and the notion of sustainability. Results: The main conclusion is that the environmental management system does not support an understanding of sustainability beyond a highly instrumental focus on specific environmental issues, nor does it support the everyday practice...

  11. A Critical Review of Environmental Management System as a Tool for Sustainability

    DEFF Research Database (Denmark)

    Galamba, Kirsten Ramskov

    Purpose: The aim of the article is to make a critical review of the environmental management system as a tool for sustainability in local authorities. Background: As a point of departure sustainability is outlined as an ambivalent term that has been interpreted in a number of ways, which...... is important as the understanding informs the choice of societal response to the ecological crisis. Approach (Theory/Methodology): Action research has been used as the primary methodological approach for the empirical work and the empirical material has been analysed with respect to reflections...... on environmental management and the notion of sustainability. Results: The main conclusion is that the environmental management system does not support an understanding of sustainability beyond a highly instrumental focus on specific environmental issues, nor does it support the everyday practice...

  12. Environmental management and organisation systems. A critical review; Umweltmanagement- und Organisationssysteme. Eine kritische Durchleuchtung

    Energy Technology Data Exchange (ETDEWEB)

    Schottelius, D. [Anwaltssozietaet Hoffmann, Liebs, Fritsch und Partner, Frankfurt am Main (Germany); Kuepper-Djindjic, C. [Anwaltssozietaet Hoffmann, Liebs, Fritsch und Partner, Frankfurt am Main (Germany)

    1994-11-20

    The FRG is amongst the industrial nations with the tightest, in parts hardly comprehensible network of regulative provisions by laws, statutory orders, administrative regulations as well as technical rules and standards included in the legal system. With regard to the establishment of management and organisation systems until now there are only few statutory provisions in Germany. The article is to critically review developments and to show connections and interactions between property and procedure provisions. (orig.) [Deutsch] Die Bundesrepublik Deutschland gehoert zu den Industrielaendern mit dem dichtesten, in seinen Teilbereichen kaum noch ueber- und durchschaubaren Netz ordnungsrechtlicher Vorgaben durch Gesetze, Rechtsverordnungen, Verwaltungsvorschriften und ins Rechtssystem einbezogene technische Normen und Regelwerken. Hinsichtlich der Einrichtung von Management- und Organisationssystemen hat Deutschland bisher weitgehend auf gesetzliche Vorgaben verzichtet. Der Beitrag soll Entwicklungen kritisch beleuchten sowie Zusammenhaenge und Zusammenwirken zwischen Sach- und Verfahrensvorschriften aufzeigen. (orig.)

  13. Healthcare Team Performance in Time Critical Environments: Coordinating Events, Foraging, and System Processes

    Directory of Open Access Journals (Sweden)

    Barrett S. Caldwell

    2010-01-01

    Full Text Available This review paper addresses issues in how healthcare providers search, obtain, and share resources in provider teams. Based in part on a System of Systems (SoS analysis of provider coordination and resource flows, this paper expands the concepts of resource foraging theory and event dynamics to develop systematic methods for studying healthcare provider coordination. Process flow and human factors emphases from industrial engineering are used to address critical concerns of single-scale and multi-scale performance in healthcare delivery settings. Provider strategies for acquiring the information and resources needed for successful healthcare delivery are dependent on interactions between task requirements, time constraints, and provider coordination processes, as well as limitations of information and resource flow capabilities. These improved definitions and measures will enhance engineers' ability to contribute to improved patient care timeliness, effectiveness, quality, and safety.

  14. Multi-core System Architecture for Safety-critical Control Applications

    DEFF Research Database (Denmark)

    Li, Gang

    certification cost. Meanwhile, hardware platforms with improved processing power are required to execute the applications of larger size. To tackle the two issues mentioned above, the state of the art approaches are using more Electronic Control Units (ECU) in a federated architecture or increasing...... cores, low power consumption, on-chip interconnection and natural support to on-chip hardware diversity and redundancy at the inter-core level. The objective of this dissertation is to propose a multi-core system architecture for safety-critical control applications with reduced certification cost...... on partitioning design of both multi-core hardware and software architectures, in order to minimize efforts and cost of system certification at the integration time. Hardware architecture design concentrates on a firmware architecture on SoC platforms, providing separated hardware execution environments...

  15. Testing Result Statistics-Based Rapid Testing Method for Safety-Critical System

    Institute of Scientific and Technical Information of China (English)

    Zhi-Yao Deng; Nan Sang

    2008-01-01

    Safety-critical system (SCS) has highly demand for dependability, which requires plenty of resource to ensure that the system under test (SUT) satisfies the dependability requirement. In this paper, a new SCS rapid testing method is proposed to improve SCS adaptive dependability testing. The result of each test execution is saved in calculation memory unit and evaluated as an algorithm model. Then the least quantity of scenario test case for next test execution will be calculated according to the promised SUT's confidence level. The feedback data are generated to weight controller as the guideline for the further testing. Finally, a compre- hensive experiment study demonstrates that this adaptive testing method can really work in practice. This rapid testing method, testing result statistics-based adaptive control, makes the SCS dependability testing much more effective.

  16. Testing Result Statistics-Based Rapid Testing Method for Safety-Critical System

    Institute of Scientific and Technical Information of China (English)

    Zhi-Yao Deng; Nan Sang

    2008-01-01

    Safety-critical system (SCS) has highlydemand for dependability, which requires plenty ofresource to ensure that the system under test (SUT)satisfies the dependability requirement. In this paper, anew SCS rapid testing method is proposed to improveSCS adaptive dependability testing. The result of each testexecution is saved in calculation memory unit andevaluated as an algorithm model. Then the least quantityof scenario test case for next test execution will becalculated according to the promised SUT's confidencelevel. The feedback data are generated to weightcontroller as the guideline for the further testing. Finally,a compre- hensive experiment study demonstrates thatthis adaptive testing method can really work in practice.This rapid testing method, testing result statistics-basedadaptive control, makes the SCS dependability testingmuch more effective.

  17. Where is My Pay? Critical Success Factors of a Payroll System – A System Life Cycle Approach

    Directory of Open Access Journals (Sweden)

    Mohan Thite

    2014-06-01

    Full Text Available Majority of firms deploy technologies in HR administrative applications. While payroll processing is a routine transactional activity, poor design and implementation of payroll system can cause immense harm to employee and organizational well-being. Based on the case study of a flawed payroll system in a large and complex public sector organization in Australia, we highlight the key success factors using the system life cycle approach underpinned by the agile philosophy. It highlights the critical importance of strategic organizational review, user involvement and ongoing communication with diverse stakeholders during the planning, analysis, design, implementation and review stages of a payroll project. It reinforces the need for the adoption of and adherence to sound project and change management methodologies. We also explore the limitations of shared service center approach.

  18. Evaluation of a transcutaneous blood gas monitoring system in critically ill dogs.

    Science.gov (United States)

    Holowaychuk, Marie K; Fujita, Hiroshi; Bersenas, Alexa M E

    2014-01-01

    To describe the use of a transcutaneous blood gas monitoring system in critically ill dogs, determine if transcutaneous and arterial blood gas values have good agreement, and verify if clinical or laboratory variables are correlated with differences between transcutaneous and arterial blood gas measurements. Prospective observational study. University teaching hospital ICU. Twenty-three client-owned dogs. In critically ill dogs undergoing arterial blood gas monitoring, a transcutaneous blood gas monitor was used to measure transcutaneous partial pressure of carbon dioxide (PtcCO2 ) and transcutaneous partial pressure of oxygen (PtcO2 ) values 30 minutes after sensor placement, which were compared to PaCO2 and PaO2 values measured simultaneously. Clinical and laboratory variables were concurrently recorded to determine if they were correlated with the difference between transcutaneous and arterial blood gas measurements. Bland-Altman analysis revealed a mean bias of 4.6 ± 26.3 mm Hg (limits of agreement [LOA]: -46.9/+56.1 mm Hg) between PtcO2 and PaO2 and a mean bias of 9.3 ± 8.5 mm Hg (LOA: -7.5/+26.0 mm Hg) between PtcCO2 and PaCO2 . The difference between PtcCO2 -PaCO2 was strongly negatively correlated with HCO3 (-) (r(2) = 0.52, P blood pressure (r(2) = 0.21, P = 0.044), whereas the difference between PtcCO2 -PaCO2 was moderately negatively correlated with diastolic blood pressure (r(2) = 0.33, P = 0.008). Agreement between transcutaneous and arterial PO2 and PCO2 measurements in these critically ill dogs was inferior to that reported in similar adult and pediatric human studies. The transcutaneous monitor consistently over-estimated PaO2 and PaCO2 and should not be used to replace arterial blood gas measurements in critically ill dogs requiring blood gas interpretation. © Veterinary Emergency and Critical Care Society 2014.

  19. Enhancing the Resilience of Interdependent Critical Infrastructure Systems Using a Common Computational Framework

    Science.gov (United States)

    Little, J. C.; Filz, G. M.

    2016-12-01

    As modern societies become more complex, critical interdependent infrastructure systems become more likely to fail under stress unless they are designed and implemented to be resilient. Hurricane Katrina clearly demonstrated the catastrophic and as yet unpredictable consequences of such failures. Resilient infrastructure systems maintain the flow of goods and services in the face of a broad range of natural and manmade hazards. In this presentation, we illustrate a generic computational framework to facilitate high-level decision-making about how to invest scarce resources most effectively to enhance resilience in coastal protection, transportation, and the economy of a region. Coastal Louisiana, our study area, has experienced the catastrophic effects of several land-falling hurricanes in recent years. In this project, we implement and further refine three process models (a coastal protection model, a transportation model, and an economic model) for the coastal Louisiana region. We upscale essential mechanistic features of the three detailed process models to the systems level and integrate the three reduced-order systems models in a modular fashion. We also evaluate the proposed approach in annual workshops with input from stakeholders. Based on stakeholder inputs, we derive a suite of goals, targets, and indicators for evaluating resilience at the systems level, and assess and enhance resilience using several deterministic scenarios. The unifying framework will be able to accommodate the different spatial and temporal scales that are appropriate for each model. We combine our generic computational framework, which encompasses the entire system of systems, with the targets, and indicators needed to systematically meet our chosen resilience goals. We will start with targets that focus on technical and economic systems, but future work will ensure that targets and indicators are extended to other dimensions of resilience including those in the environmental and

  20. Large system change challenges: addressing complex critical issues in linked physical and social domains

    Science.gov (United States)

    Waddell, Steve; Cornell, Sarah; Hsueh, Joe; Ozer, Ceren; McLachlan, Milla; Birney, Anna

    2015-04-01

    Most action to address contemporary complex challenges, including the urgent issues of global sustainability, occurs piecemeal and without meaningful guidance from leading complex change knowledge and methods. The potential benefit of using such knowledge is greater efficacy of effort and investment. However, this knowledge and its associated tools and methods are under-utilized because understanding about them is low, fragmented between diverse knowledge traditions, and often requires shifts in mindsets and skills from expert-led to participant-based action. We have been engaged in diverse action-oriented research efforts in Large System Change for sustainability. For us, "large" systems can be characterized as large-scale systems - up to global - with many components, of many kinds (physical, biological, institutional, cultural/conceptual), operating at multiple levels, driven by multiple forces, and presenting major challenges for people involved. We see change of such systems as complex challenges, in contrast with simple or complicated problems, or chaotic situations. In other words, issues and sub-systems have unclear boundaries, interact with each other, and are often contradictory; dynamics are non-linear; issues are not "controllable", and "solutions" are "emergent" and often paradoxical. Since choices are opportunity-, power- and value-driven, these social, institutional and cultural factors need to be made explicit in any actionable theory of change. Our emerging network is sharing and building a knowledge base of experience, heuristics, and theories of change from multiple disciplines and practice domains. We will present our views on focal issues for the development of the field of large system change, which include processes of goal-setting and alignment; leverage of systemic transitions and transformation; and the role of choice in influencing critical change processes, when only some sub-systems or levels of the system behave in purposeful ways

  1. ANALYSIS OF DISTURBANCE TORQUE INFLUENCE ON CRITICAL STATE IN ROTATIONAL SYSTEMS

    Directory of Open Access Journals (Sweden)

    Bogumił CHILIŃSKI

    2013-12-01

    Full Text Available Currently most of existing means of transport contains different types of rotational systems. In many cases the dynamics of such rotors substantially can influence exploitation of the whole vehicle. Moreover, in order to minimize mass of the whole object modern construction materials are applied. This causes that the dynamic phenomena may be fundamental of exploitation. The paper presents preliminary analysis of disturbance torque influence on critical state in rotational system. The consideration assumed simple physical object in the form of heavy disk embedded on weightless, elastic shaft. The shaft was supported on two bearings. In particular chapters of paper, path leading from proposition of physical model, by solution of it, to qualitative conclusions about considered object and torque disturbances influence of motion of this system, was presented. In introduction, outline of considered problem and potential opportunities of it, were demonstrated. In the next chapter, physical and mathematical model of the analysed object, was described. Next and also the last but one chapter gives a detailed discussion of mathematical model in the form of nonlinear ordinary differential equations proposed earlier. The first part of the chapter presents the possibility to solve such a problem, then it shows the simplifications which are used. Furthermore, the influence of used simplifications on the shape of analysed problem was demonstrated. Additionally, the possibility of equations solution presented in the paper was discussed. Moreover, the series of interesting properties of analysed system of equations has been shown based on founded approximate solutions. The whole paper was summarized with plans for future work and synthetic conclusions concerning the innovative control method of critical states.

  2. Nuclear data requirements for accelerator driven sub-critical systems – A roadmap in the Indian context

    Indian Academy of Sciences (India)

    S Ganesan

    2007-02-01

    The development of accelerator driven sub-critical systems (ADSS) require significant amount of new nuclear data in extended energy regions as well as for a variety of new materials. This paper reviews these perspectives in the Indian context.

  3. Critical Research Needed to Examine the Environmental Impacts of Expanded Refrigeration on the Food System.

    Science.gov (United States)

    Heard, Brent R; Miller, Shelie A

    2016-11-15

    The unbroken global refrigerated supply chain, or cold chain, is rapidly expanding in developing countries. In addition to increasing the energy intensity of the food system, the expanded cold chain may facilitate changes in the global diet, food waste patterns, food production and distribution, and shopping habits. The sustainability impacts of many of these changes chain are unknown, given the complexity of interacting social, economic, and technical factors. The current literature surrounding the environmental impacts of refrigeration in the food system focuses on the direct impacts of energy use and coolant emissions, and lacks a critical evaluation of the accompanying systemic societal changes that potentially carry greater environmental impacts. This review examines the cold chain as a transformative technology, identifying key intrinsic, indirect, and external factors that will favorably, unfavorably, or ambiguously impact the environmental profile of the food system. The review identifies key interactions and feedbacks between the cold chain, food production and consumption decisions, infrastructure development, and the global environment which are largely unexamined and in need of empirical data. Viewing cold chain expansion from this broader perspective is essential to understanding the changing impacts of the food system in developing countries and may inform future sustainability planning.

  4. Architecture and critical technologies of seismic information system in CTBT verification

    Institute of Scientific and Technical Information of China (English)

    ZHENG Xue-feng; SHEN Jun-yi; JIN Ping; ZHENG Jiang-ling; SUN Peng; ZHANG Hui-min; WANG Tong-dong

    2006-01-01

    Seismic monitoring is one of the most important approaches for ground-based nuclear explosion monitoring. In order to improve the monitoring capability for low magnitude seismic events, a seismic information system was developed by using the technologies of geographic information system and database. This paper describes the designing and critical technologies of the Seismic Information System in CTBT Verification developed based on ArcGIS and ORACLE platforms. It is a combination of the database storage framework, application programming interface and graphic application software for users to meet their monitoring objectives. Combining the ArcSDE Geodatabase, RDBMS ORACLE and ArcObjects developing technique on COM, not only the multi-sources data has been seamlessly integrated, but also the most functions of ORACLE, for example, consistency, concurrent access, security mechanism, etc, have been reserved. For easy access to the information system we develop two different mechanisms. The first is a menu-driven internal system that is run on NT platforms. The second access mechanism is based on LAN and easily accessible by any web browsers.

  5. Approximation and Filtering Techniques for Navigation Data in Time-critical Electronic Warfare Systems

    Directory of Open Access Journals (Sweden)

    Vanitha D.

    2013-03-01

    Full Text Available This paper presents a holistic solution to the navigation requirements in a time critical electronic warfare systems like missile warning systems (MWS. In a passive MWS using IR sensors the efficiency of the system is determined by attributes such as low false alarm rate, minimal response time and ability to track different IR radiating objects by association and correlation of consecutive detections through time. Such a system is required to be supported by a navigation system capable of accurate estimation of the aircraft position, attitude angles and altitude. In this paper, estimation techniques used to accurately calculate aircraft navigation data at the time of capture of IR frames are discussed. The paper discusses about synchronization of INGPS, IR sensors & Processor on to same timeline. The paper also intends to evaluate the performance of wavelet transform filter in effective elimination of noise in navigation parameters like acceleration and attitude angle rates for a better estimation of position and attitude.Defence Science Journal, 2013, 63(2, pp.204-209, DOI:http://dx.doi.org/10.14429/dsj.63.4265

  6. Low frequency critical current noise and two level system defects in Josephson junctions

    Science.gov (United States)

    Nugroho, Christopher Daniel

    The critical current in a Josephson junction is known to exhibit a 1/falpha low frequency noise. Implemented as a superconducting qubit, this low frequency noise can lead to decoherence. While the 1/f noise has been known to arise from an ensemble of two level systems connected to the tunnel barrier, the precise microscopic nature of these TLSs remain a mystery. In this thesis we will present measurements of the 1/f alpha low frequency noise in the critical current and tunneling resistance of Al-AlOx-Al Josephson junctions. Measurements in a wide range of resistively shunted and unshunted junctions confirm the equality of critical current and tunneling resistance noise. That is the critical current fluctuation corresponds to fluctuations of the tunneling resistance. In not too small Al-AlOx-Al junctions we have found that the fractional power spectral density scales linearly with temperature. We confirmed that the 1/falpha power spectrum is the result of a large number of two level systems modulating the tunneling resistance. At small junction areas and low temperatures, the number of thermally active TLSs is insufficient to integrate out a featureless 1/ f spectral shape. By analyzing the spectral variance in small junction areas, we have been able to deduce the TLS defect density, n ≈ 2.53 per micrometer squared per Kelvin spread in the TLS energy per factor e in the TLS lifetimes. This density is consistent with the density of tunneling TLSs found in glassy insulators, as well as the density deduced from coherent TLSs interacting at qubit frequencies. The deduced TLS density combined with the magnitude of the 1/f power spectral density in large area junctions, gives an average TLS effective area, A ˜ 0.3 nanometer squared. In ultra small tunnel junctions, we have studied the time-domain dynamics of isolated TLSs. We have found a TLS whose dynamics is described by the quantum tunneling between the two localized wells, and a one-phonon absorption

  7. Application of SCALE4.4 system for burnup credit criticality analysis of PWR spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hee Sung; Ro, Seung gy; Bae, Kang mok; Shin, YoungJoon; Kim, Ik Soo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-07-01

    An investigation on the application of burnup credit for a PWR spent fuel storage pool has been carried out with the use of the SCALE 4.4 computer code system consisting of SAS2H and CSAS6 modules in association with 44-group SCALE cross-section library. Prior to the application of the computer code system, a series of bench markings have been performed in comparison with available data. A benchmarking of the SAS2h module has been done for experimental concentration data of 54 PWR spent fuel and then correction factors with a 95% probability at a 95% confidence level have been determined on the basis of the calculated and measured concentrations of 38 nuclides. After that, the bias which might have resulted from the use of the CSAS6 module has been calculated for 46 criticality experimental data of UO{sub 2} fuel and MOX fuel assemblies. The calculation bias with one-sided tolerance limit factor (2.086) corresponding to a 95% probability at a 95% confidence level has consequently been obtained to be 0.00834. Burnup credit criticality analysis has been done for the PWR spent fuel storage pool by means of the benchmarked or validated code system. It is revealed that the minimum burnup for safe storage is 7560 MWd/tU in 5 wt% enriched fuel if both actinides and fission products in spent fuel are taken into account. However, the minimum value required seems to be 9,565 MWd/tU in the same enriched fuel provided that only the actinides are taken into consideration. (author)

  8. Polarized and depolarized light-scattering studies on Brownian diffusional and critical fluid systems: theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, C.M.

    1976-01-01

    An effort to expand light-scattering autocorrelation techniques to Brownian diffusional and critical fluid systems in which multiple scattering effects are important, and to understand the observed similarity of the Rayleigh linewidth of light scattered from these two seemingly different systems is discussed. A formalism was developed to find the light field multiply scattered from a suspension of Brownian diffusing particles. For the field doubly scattered from a system of noninteracting Brownian particles, the intensity and correlation time were much less dependent on the scattering angle than for the singly scattered component. The polarized and depolarized correlation times of light scattered from Brownian particle systems were measured. The double-scattering formalism was extended to light scattered from critical fluid systems. In the region k xi greater than 5 the doubly and singly scattered correlation times were nearly equal. The dynamic droplet model of critical phenomena was developed which gives the proper, experimentally verified, forms for the intensity and linewidth of light scattered from a critical fluid. To test the dynamic droplet model and the mode theories Rayleigh linewidth predictions, light-scattering measurements were performed on the critical fluid system methanol and cyclohexane. The data agreed with both the dynamic droplet and decoupled mode theory predictions. The depolarized scattered spectra from a critical fluid were measured, and qualitative agreement with the double-scattering theory was found. 57 figures, 5 tables.

  9. Interhospital Transport System for Critically Ill Patients: Mobile Extracorporeal Membrane Oxygenation without a Ventilator

    Science.gov (United States)

    Yeo, Hye Ju; Cho, Woo Hyun; Park, Jong Myung; Kim, Dohyung

    2017-01-01

    Background Extracorporeal membrane oxygenation (ECMO) has been successfully used as a method for the interhospital transportation of critically ill patients. In South Korea, a well-established ECMO interhospital transport system is lacking due to limited resources. We developed a simplified ECMO transport system without mechanical ventilation for use by public emergency medical services. Methods Eighteen patients utilized our ECMO transport system from December 2011 to September 2015. We retrospectively analyzed the indications for ECMO, the patient status during transport, and the patient outcomes. Results All transport was conducted on the ground by ambulance. The distances covered ranged from 26 to 408 km (mean, 65.9±88.1 km) and the average transport time was 56.1±57.3 minutes (range, 30 to 280 minutes). All patients were transported without adverse events. After transport, 4 patients (22.2%) underwent lung transplantation because of interstitial lung disease. Eight patients who had severe acute respiratory distress syndrome showed recovery of heart and lung function after ECMO therapy. A total of 13 patients (70.6%) were successfully taken off ECMO, and 11 patients (61.1%) survived. Conclusion Our ECMO transport system without mechanical ventilation can be considered a safe and useful method for interhospital transport and could be a good alternative option for ECMO transport in Korean hospitals with limited resources. PMID:28180097

  10. Design and validation of a questionnaire to evaluate the usability of computerized critical care information systems.

    Science.gov (United States)

    von Dincklage, Falk; Lichtner, Gregor; Suchodolski, Klaudiusz; Ragaller, Maximilian; Friesdorf, Wolfgang; Podtschaske, Beatrice

    2016-06-03

    The implementation of computerized critical care information systems (CCIS) can improve the quality of clinical care and staff satisfaction, but also holds risks of disrupting the workflow with consecutive negative impacts. The usability of CCIS is one of the key factors determining their benefits and weaknesses. However, no tailored instrument exists to measure the usability of such systems. Therefore, the aim of this study was to design and validate a questionnaire that measures the usability of CCIS. Following a mixed-method design approach, we developed a questionnaire comprising two evaluation models to assess the usability of CCIS: (1) the task-specific model rates the usability individually for several tasks which CCIS could support and which we derived by analyzing work processes in the ICU; (2) the characteristic-specific model rates the different aspects of the usability, as defined by the international standard "ergonomics of human-system interaction". We tested validity and reliability of the digital version of the questionnaire in a sample population. In the sample population of 535 participants both usability evaluation models showed a strong correlation with the overall rating of the system (multiple correlation coefficients ≥0.80) as well as a very high internal consistency (Cronbach's alpha ≥0.93). The novel questionnaire is a valid and reliable instrument to measure the usability of CCIS and can be used to study the influence of the usability on their implementation benefits and weaknesses.

  11. Outcomes and organ dysfunctions of critically ill patients with systemic lupus erythematosus and other systemic rheumatic diseases

    Directory of Open Access Journals (Sweden)

    O.T. Ranzani

    2011-11-01

    Full Text Available Our objective was to compare the pattern of organ dysfunctions and outcomes of critically ill patients with systemic lupus erythematosus (SLE with patients with other systemic rheumatic diseases (SRD. We studied 116 critically ill SRD patients, 59 SLE and 57 other-SRD patients. The SLE group was younger and included more women. Respiratory failure (61% and shock (39% were the most common causes of ICU admission for other-SRD and SLE groups, respectively. ICU length-of-stay was similar for the two groups. The 60-day survival adjusted for the groups’ baseline imbalances was not different (P = 0.792. Total SOFA scores were equal for the two groups at admission and during ICU stay, although respiratory function was worse in the other-SRD group at admission and renal and hematological functions were worse in the SLE group at admission. The incidence of severe respiratory dysfunction (respiratory SOFA >2 at admission was higher in the other-SRD group, whereas severe hematological dysfunction (hematological SOFA >2 during ICU stay was higher in the SLE group. SLE patients were younger and displayed a decreased incidence of respiratory failure compared to patients with other-SRDs. However, the incidences of renal and hematological failure and the presence of shock at admission were higher in the SLE group. The 60-day survival rates were similar.

  12. Geo-engineering, Governance, and Social-Ecological Systems: Critical Issues and Joint Research Needs

    Directory of Open Access Journals (Sweden)

    Victor Galaz

    2012-03-01

    Full Text Available The debate about the possibilities to engineer the Earth's climate has changed drastically in the last years. Suggestions of large-scale technological interventions to combat climate change that a decade ago would have been discarded as science fiction are slowly moving into the center of international climate change discussions, research, and politics. In this article, I elaborate three joint key challenges to geo-engineering research from a resilience perspective, with a special emphasis on governance issues. First, I discuss the need to understand geo-engineering proposals from a "planetary boundaries" perspective. Second, I elaborate why the notion of Earth stewardship and geo-engineering are not necessarily in conflict, but instead could be viewed as complementary approaches. Last, I discuss the critical need to explore an institutional setting that is strong enough to weed out geo-engineering proposals that carry considerable ecological risk, but still allow for novelty, fail-safe experimentation, and continuous learning. These issues are critical for our understanding of how to effectively govern global environmental risks, complex systems, and emerging technologies in the Anthropocene.

  13. New quantum-critical-point-related effects in Ce lattice systems

    Energy Technology Data Exchange (ETDEWEB)

    Sereni, J.G. [Division Bajas Temperaturas, Centro Atomico Bariloche (CNEA), 8400 S.C. de Bariloche (Argentina)]. E-mail: jsereni@cab.cnea.gov.ar

    2004-12-31

    Anomalous physical properties related to quantum critical points are investigated in Ce-systems whose magnetic phase boundaries, TN,C(x,p), can be traced for at least one decade of temperature. A change from the usual negative curvature to a linear concentration, x, dependence of TN,C(x) is observed at x*>=xcr/2 (xcr being the critical concentration). Within the x*xxcr region, the usual specific heat temperature dependence Cm/T{proportional_to}Ln(1/T) develops above TN,C, while a nearly constant value of Cm/T maximum is observed besides a scaling of Cm/T(T) with {delta}T=T-TN,C. Coincidentally, a significant increase of the zero-point entropy S0(x)(=RLn2-Sm(x,T)) occurs. Dimensionality and dynamics of the spin fluctuations can be analyzed computing the internal energy and entropy for T>=TN and AC-susceptibility results. Consequences for the free-energy evolution within this region and implications of the S0(x) increase are discussed.

  14. Cytoskeletal actin networks in motile cells are critically self-organized systems synchronized by mechanical interactions.

    Science.gov (United States)

    Cardamone, Luca; Laio, Alessandro; Torre, Vincent; Shahapure, Rajesh; DeSimone, Antonio

    2011-08-23

    Growing networks of actin fibers are able to organize into compact, stiff two-dimensional structures inside lamellipodia of crawling cells. We put forward the hypothesis that the growing actin network is a critically self-organized system, in which long-range mechanical stresses arising from the interaction with the plasma membrane provide the selective pressure leading to organization. We show that a simple model based only on this principle reproduces the stochastic nature of lamellipodia protrusion (growth periods alternating with fast retractions) and several of the features observed in experiments: a growth velocity initially insensitive to the external force; the capability of the network to organize its orientation; a load-history-dependent growth velocity. Our model predicts that the spectrum of the time series of the height of a growing lamellipodium decays with the inverse of the frequency. This behavior is a well-known signature of self-organized criticality and is confirmed by unique optical tweezer measurements performed in vivo on neuronal growth cones.

  15. Real Space Migdal-Kadanoff Renormalisation of Glassy Systems: Recent Results and a Critical Assessment

    Science.gov (United States)

    Angelini, Maria Chiara; Biroli, Giulio

    2017-05-01

    In this manuscript, in honour of L. Kadanoff, we present recent progress obtained in the description of finite dimensional glassy systems thanks to the Migdal-Kadanoff renormalisation group (MK-RG). We provide a critical assessment of the method, in particular discuss its limitation in describing situations in which an infinite number of pure states might be present, and analyse the MK-RG flow in the limit of infinite dimensions. MK-RG predicts that the spin-glass transition in a field and the glass transition are governed by zero-temperature fixed points of the renormalization group flow. This implies a typical energy scale that grows, approaching the transition, as a power of the correlation length, thus leading to enormously large time-scales as expected from experiments and simulations. These fixed points exist only in dimensions larger than d_L>3 but they nevertheless influence the RG flow below it, in particular in three dimensions. MK-RG thus predicts a similar behavior for spin-glasses in a field and models of glasses and relates it to the presence of avoided critical points.

  16. Critical aspects of integrated monitoring systems for landslides risk management: strategies for a reliable approach

    Science.gov (United States)

    Castagnetti, C.; Bertacchini, E.; Capra, A.; Corsini, A.

    2012-04-01

    The use of advanced technologies for remotely monitor surface processes is a successful way for improving the knowledge of phenomena evolution. In addition, the integration of various techniques is becoming more and more common in order to implement early warning systems that can monitor the evolution of landslides in time and prevent emergencies. The reliability of those systems plays a key role when Public Administrations have to plan actions in case of disasters or for preventing an incoming emergency. To have confidence in the information given by the system is an essential condition for a successful policy aiming to protect the population. The research deals with the major critical aspects to be taken into account when implementing a reliable monitoring system for unstable slopes. The importance of those aspects is often neglected, unlike the effects of a not careful implementation and management of the system can lead to erroneous interpretations of the phenomenon itself. The case study which ruled the research and highlighted the actual need of guidelines for setting up a reliable monitoring system is the Valoria landslide, located in the Northern Italy. The system is based on the integration of an automatic Total Station (TS) measuring 45 reflectors and a master GPS, acting as the reference station for three rovers placed within the landslide. In order to monitor local disturbing effects, a bi-dimensional clinometer has been applied on the TS pillar. Topographic measurements have been also integrated with geotechnical sensors (inclinometers and piezometers) in a GIS for landslide risk management. At the very beginning, periodic measurements were carried out, while the system is now performing continuously since 2008. The system permitted to evaluate movements from few millimeter till some meters per day in most dangerous areas. A more spatially continuous description has been also provided by LiDAR and terrestrial SAR interferometry. Some of the most

  17. Mapping Systemic Risk: Critical Degree and Failures Distribution in Financial Networks.

    Science.gov (United States)

    Smerlak, Matteo; Stoll, Brady; Gupta, Agam; Magdanz, James S

    2015-01-01

    The financial crisis illustrated the need for a functional understanding of systemic risk in strongly interconnected financial structures. Dynamic processes on complex networks being intrinsically difficult to model analytically, most recent studies of this problem have relied on numerical simulations. Here we report analytical results in a network model of interbank lending based on directly relevant financial parameters, such as interest rates and leverage ratios. We obtain a closed-form formula for the "critical degree" (the number of creditors per bank below which an individual shock can propagate throughout the network), and relate failures distributions to network topologies, in particular scalefree ones. Our criterion for the onset of contagion turns out to be isomorphic to the condition for cooperation to evolve on graphs and social networks, as recently formulated in evolutionary game theory. This remarkable connection supports recent calls for a methodological rapprochement between finance and ecology.

  18. Mapping Systemic Risk: Critical Degree and Failures Distribution in Financial Networks.

    Directory of Open Access Journals (Sweden)

    Matteo Smerlak

    Full Text Available The financial crisis illustrated the need for a functional understanding of systemic risk in strongly interconnected financial structures. Dynamic processes on complex networks being intrinsically difficult to model analytically, most recent studies of this problem have relied on numerical simulations. Here we report analytical results in a network model of interbank lending based on directly relevant financial parameters, such as interest rates and leverage ratios. We obtain a closed-form formula for the "critical degree" (the number of creditors per bank below which an individual shock can propagate throughout the network, and relate failures distributions to network topologies, in particular scalefree ones. Our criterion for the onset of contagion turns out to be isomorphic to the condition for cooperation to evolve on graphs and social networks, as recently formulated in evolutionary game theory. This remarkable connection supports recent calls for a methodological rapprochement between finance and ecology.

  19. Proceedings of the International Symposium on Topological Aspects of Critical Systems and Networks

    Science.gov (United States)

    Yakubo, Kousuke; Amitsuka, Hiroshi; Ishikawa, Goo; Machino, Kazuo; Nakagaki, Toshiyuki; Tanda, Satoshi; Yamada, Hideto; Kichiji, Nozomi

    2007-07-01

    I. General properties of networks. Physics of network security / Y.-C. Lai, X. Wand and C. H. Lai. Multi-state interacting particle systems on scale-free networks / N. Masuda and N. Konno. Homotopy Reduction of Complex Networks 18 / Y. Hiraoka and T. Ichinomiya. Analysis of the Susceptible-Infected-Susceptible Model on Complex Network / T. Ichinomiya -- II. Complexity in social science. Innovation and Development in a Random Lattice / J. Lahtinen. Long-tailed distributions in biological systems: revisit to Lognormals / N. Kobayashi ... [et al.]. Two-class structure of income distribution in the USA:exponential bulk and power-law tail / V. M. Yakovenko and A. Christian Silva. Power Law distributions in two community currencies / N. Kichiji and M. Nishibe -- III. Patterns in biological objects. Stoichiometric network analysis of nonlinear phenomena in rection mechanism for TWC converters / M. Marek ... [et al.]. Collective movement and morphogenesis of epithelial cells / H. Haga and K. Kawabata. Indecisive behavior of amoeba crossing an environmental barrier / S. Takagi ... [et al.]. Effects of amount of food on path selection in the transport network of an amoeboid organism / T. Nakagaki ... [et al.]. Light scattering study in double network gels / M. Fukunaya ... [et al.].Blood flow velocity in the choroid in punctate inner choroidopathy and Vogt-Koyanagi-Harada disease; amd multifractal analysis of choroidal blood flow in age-related macular degeneration / K. Yoshida ... [et al.]. Topological analysis of placental arteries: correlation with neonatal growth / H. Yamada and K. Yakubo -- IV. Criticality in pure and applied physics. Droplets in Disordered Metallic Quantum Critical Systems / A. H. Castro Neto and B. A. Jones. Importance of static disorder and inhomogeneous cooperative dynamics in heavy-fermion metals / O. O. Bernal. Competition between spin glass and Antiferromagnetic phases in heavy fermion materials / S. Sullow. Emergent Phases via Fermi surface

  20. Critical wetting transitions in two-dimensional systems subject to long-ranged boundary fields

    Science.gov (United States)

    Drzewiński, A.; Maciołek, A.; Barasiński, A.; Dietrich, S.

    2009-04-01

    Using the quasiexact density-matrix renormalization-group method and ground-state analysis we study interface delocalization transitions in wide two-dimensional Ising strips subject to long-ranged boundary fields with opposite signs at the two surfaces. Based on this approach, our explicit calculations demonstrate that critical wetting transitions do exist for semi-infinite two-dimensional systems even if the corresponding effective interface potentials decay asymptotically for large ℓ as slow as ℓ-δ with δinterface position from the one-dimensional surface. This supersedes opposite claims by Kroll and Lipowsky [Phys. Rev. B 28, 5273 (1983)] and by Privman and Švrakić [Phys. Rev. B 37, 5974 (1988)] obtained within effective interface models. The corresponding wetting phase diagram is determined, including the cases δ=2 and δ=49 with the latter mimicking short-ranged surface fields. Our analysis highlights the limits of reliability of effective interface models.

  1. Critical fluctuations and anomalous transport in soft Yukawa-Langevin systems.

    Science.gov (United States)

    Ratynskaia, S; Regnoli, G; Rypdal, K; Klumov, B; Morfill, G

    2009-10-01

    Simulation of a Langevin-dynamics model demonstrates emergence of critical fluctuations and anomalous grain transport which have been observed in experiments on "soft" quasi-two-dimensional dusty plasma clusters. Our model does not contain external drive or plasma interactions that serve to drive the system away from thermodynamic equilibrium. The grains are confined by an external potential, interact via static Yukawa forces, and are subject to stochastic heating and dissipation from neutrals. One remarkable feature is emergence of leptokurtic probability distributions of grain displacements xi(tau) on time scales tau tau(Delta). The latter is a signature of intermittency, here interpreted as a transition from bursty transport associated with hopping on intermediate time scales to vortical flows on longer time scales. These intermittency features are quantitatively modeled by a single-particle Itô-Langevin stochastic equation with a nonlinear drift term.

  2. Pathogen Reduction and Hazard Analysis and Critical Control Point (HACCP) systems for meat and poultry. USDA.

    Science.gov (United States)

    Hogue, A T; White, P L; Heminover, J A

    1998-03-01

    The United States Department of Agriculture (USDA) Food Safety Inspection Service (FSIS) adopted Hazard Analysis and Critical Control Point Systems and established finished product standards for Salmonella in slaughter plants to improve food safety for meat and poultry. In order to make significant improvements in food safety, measures must be taken at all points in the farm-to-table chain including production, transportation, slaughter, processing, storage, retail, and food preparation. Since pathogens can be introduced or multiplied anywhere along the continuum, success depends on consideration and comparison of intervention measures throughout the continuum. Food animal and public health veterinarians can create the necessary preventative environment that mitigates risks for food borne pathogen contamination.

  3. Critical wetting transitions in two-dimensional systems subject to long-ranged boundary fields.

    Science.gov (United States)

    Drzewiński, A; Maciołek, A; Barasiński, A; Dietrich, S

    2009-04-01

    Using the quasiexact density-matrix renormalization-group method and ground-state analysis we study interface delocalization transitions in wide two-dimensional Ising strips subject to long-ranged boundary fields with opposite signs at the two surfaces. Based on this approach, our explicit calculations demonstrate that critical wetting transitions do exist for semi-infinite two-dimensional systems even if the corresponding effective interface potentials decay asymptotically for large l as slow as l(-delta) with deltainterface position from the one-dimensional surface. This supersedes opposite claims by Kroll and Lipowsky [Phys. Rev. B 28, 5273 (1983)] and by Privman and Svrakić [Phys. Rev. B 37, 5974 (1988)] obtained within effective interface models. The corresponding wetting phase diagram is determined, including the cases delta=2 and delta=49 with the latter mimicking short-ranged surface fields. Our analysis highlights the limits of reliability of effective interface models.

  4. Local and Global Well-Posedness for the Critical Schrodinger-Debye System

    CERN Document Server

    Corcho, Adan J; Silva, Jorge Drumond

    2011-01-01

    We establish local well-posedness results for the Initial Value Problem associated to the Schr\\"odinger-Debye system in dimensions $N=2, 3$ for data in $H^s\\times H^{\\ell}$, with $s$ and $\\ell$ satisfying $\\max \\{0, s-1\\} \\le \\ell \\le \\min\\{2s, s+1\\}$. In particular, these include the energy space $H^1\\times L^2$. Our results improve the previous ones obtained in \\cite{Bidegaray1}, \\cite{Bidegaray2} and \\cite{Corcho-Linares}. Moreover, in the critical case ($N=2$) and for initial data in $H^1\\times L^2$, we prove that solutions exist for all times, thus providing a negative answer to the open problem mentioned in \\cite{Fibich-Papanicolau} concerning the formation of singularities for these solutions.

  5. Interoperable Medical Instrument Networking and Access System with Security Considerations for Critical Care

    Directory of Open Access Journals (Sweden)

    Deniz Gurkan

    2010-01-01

    Full Text Available The recent influx of electronic medical records in the health care field, coupled with the need of providing continuous care to patients in the critical care environment, has driven the need for interoperability of medical devices. Open standards are needed to support flexible processes and interoperability of medical devices, especially in intensive care units. In this paper, we present an interoperable networking and access architecture based on the CAN protocol. Predictability of the delay of medical data reports is a desirable attribute that can be realized using a tightly-coupled system architecture. Our simulations on network architecture demonstrate that a bounded delay for event reports offers predictability. In addition, we address security issues related to the storage of electronic medical records. We present a set of open source tools and tests to identify the security breaches, and appropriate measures that can be implemented to be compliant with the HIPAA rules.

  6. Utilizing product configuration systems for supporting the critical parts of the engineering processes

    DEFF Research Database (Denmark)

    Kristjansdottir, Katrin; Shafiee, Sara; Hvam, Lars

    2016-01-01

    Engineering-To-Order (ETO) companies have to respond to increasing demands to provide highly customized and complex products with high quality at competitive prices. In order to respond to those challenges ETO companies have started to implement product configuration systems (PCS) to increase...... efficiency of the specification processes. As a result to complex products and processes in ETO companies, PCS are usually gradually implemented where only subsets of the products are included to support specific processes. However, a systematic way to identify and evaluate the products and the processes...... to be supported with the PCSs is not described in the current literature. This paper aims to pursue that research opportunity by presenting a framework, which aims to identifying the critical parts of the engineering processes in order to identify where it most beneficial to implement a PCSs and how to prioritize...

  7. Computer assisted active learning system development for critical thinking in history of civilization

    Directory of Open Access Journals (Sweden)

    Adem Karahoca

    2010-03-01

    Full Text Available This study investigates a Computer Assisted Learning System (CALS according to the several factors that promote flow wherestudents are fully involved into the learning activities for history of civilization lessons. The designed CALS supported bymeta – cognitive (cognitive maps and multimedia tools (movies, flash cards and quiz applications that help students to reacha flow state in learning by actively by engaging students’ critical thinking and providing an environment for active participation.The research data was collected using focus group surveys from a randomly selected 54 students enrolled in history ofcivilization at Bahcesehir University in Istanbul, Turkey. Results showed that 53.7% of students can be in flow via implementedCALS. Also according to the results, the flow has significant predictors in the course enjoyment, perceived competence ofcourse, value–usefulness and the challenge–learning style match according to nature of course in such a CALS.

  8. Direct three-dimensional ordering of quasi-one-dimensional quantum dimer system near critical fields

    Science.gov (United States)

    Matsushita, Taku; Hori, Nobuyoshi; Takata, Seiya; Wada, Nobuo; Amaya, Naoki; Hosokoshi, Yuko

    2017-01-01

    Dimensionalities of X X Z spin orderings or degenerate hard-core bosons in a quasi-one-dimensional (1D) dimer system are examined by the ac susceptibility and specific heat of antiferromagnetic bond-alternating chains in pentafluorophenyl nitronyl nitroxide (F5PNN ). At intermediate fields in the gapless region, the 1D short-range order (SRO) corresponding to the Tomonaga-Luttinger liquid and three-dimensional (3D) long-range order (LRO BEC) at lower temperatures are separately observed, as expected from the small interchain interaction. In contrast, a definite region around the critical field was established where 3D LRO occurs without the development of 1D SRO at higher temperatures.

  9. Magnetic and superconducting quantum critical points of heavy-fermion systems

    Energy Technology Data Exchange (ETDEWEB)

    Demuer, A.; Sheikin, I.; Braithwaite, D. E-mail: dbraithwaite@cea.fr; Faak, B.; Huxley, A.; Raymond, S.; Flouquet, J

    2001-05-01

    Two examples of heavy-fermion systems are presented : CePd{sub 2}Si{sub 2}, an antiferromagnet with a quantum critical point at P{sub C}=28 kbar and UGe{sub 2} an itinerant ferromagnet which transits in a paramagnetic phase above P{sub C}=16 kbar. In CePd{sub 2}Si{sub 2} the superconductivity domain is centered on P{sub C}. Special attention was given to the superconducting and magnetic anomalies at their superconducting and Neel temperatures. In UGe{sub 2} superconductivity appears in 9 kbar at a temperature T{sub S}, more than two orders of magnitude lower than the Curie temperature; furthermore, it occurs only on the magnetic border (P

  10. Magnetic and superconducting quantum critical points of heavy-fermion systems

    Science.gov (United States)

    Demuer, A.; Sheikin, I.; Braithwaite, D.; Fåk, B.; Huxley, A.; Raymond, S.; Flouquet, J.

    2001-05-01

    Two examples of heavy-fermion systems are presented : CePd 2Si 2, an antiferromagnet with a quantum critical point at PC=28 kbar and UGe 2 an itinerant ferromagnet which transits in a paramagnetic phase above PC=16 kbar. In CePd 2Si 2 the superconductivity domain is centered on PC. Special attention was given to the superconducting and magnetic anomalies at their superconducting and Néel temperatures. In UGe 2 superconductivity appears in 9 kbar at a temperature TS, more than two orders of magnitude lower than the Curie temperature; furthermore, it occurs only on the magnetic border ( P< PC). Another characteristic temperature TX is detected by resistivity; the zigzag uranium chain of the lattice may favor a supplementary nesting in the majority spin band.

  11. A Comparison of Bus Architectures for Safety-Critical Embedded Systems

    Science.gov (United States)

    Rushby, John; Miner, Paul S. (Technical Monitor)

    2003-01-01

    We describe and compare the architectures of four fault-tolerant, safety-critical buses with a view to deducing principles common to all of them, the main differences in their design choices, and the tradeoffs made. Two of the buses come from an avionics heritage, and two from automobiles, though all four strive for similar levels of reliability and assurance. The avionics buses considered are the Honeywell SAFEbus (the backplane data bus used in the Boeing 777 Airplane Information Management System) and the NASA SPIDER (an architecture being developed as a demonstrator for certification under the new DO-254 guidelines); the automobile buses considered are the TTTech Time-Triggered Architecture (TTA), recently adopted by Audi for automobile applications, and by Honeywell for avionics and aircraft control functions, and FlexRay, which is being developed by a consortium of BMW, DaimlerChrysler, Motorola, and Philips.

  12. MCNP5 CRITICALITY VALIDATION AND BIAS FOR INTERMEDIATE ENRICHED URANIUM SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    FINFROCK SH

    2009-12-10

    The purpose of this analysis is to validate the Monte Carlo N-Particle 5 (MCNP5) code Version 1.40 (LA-UR-03-1987, 2005) and its cross-section database for k-code calculations of intermediate enriched uranium systems on INTEL{reg_sign} processor based PC's running any version of the WINDOWS operating system. Configurations with intermediate enriched uranium were modeled with the moderator range of 39 {le} H/Fissile {le} 1438. See Table 2-1 for brief descriptions of selected cases and Table 3-1 for the range of applicability for this validation. A total of 167 input cases were evaluated including bare and reflected systems in a single body or arrays. The 167 cases were taken directly from the previous (Version 4C [Lan 2005]) validation database. Section 2.0 list data used to calculate k-effective (k{sub eff}) for the 167 experimental criticality benchmark cases using the MCNP5 code v1.40 and its cross section database. Appendix B lists the MCNP cross-section database entries validated for use in evaluating the intermediate enriched uranium systems for criticality safety. The dimensions and atom densities for the intermediate enriched uranium experiments were taken from NEA/NSC/DOC(95)03, September 2005, which will be referred to as the benchmark handbook throughout the report. For these input values, the experimental benchmark k{sub eff} is approximately 1.0. The MCNP validation computer runs ran to an accuracy of approximately {+-} 0.001. For the cases where the reported benchmark k{sub eff} was not equal to 1.0000 the MCNP calculational results were normalized. The difference between the MCNP validation computer runs and the experimentally measured k{sub eff} is the MCNP5 v1.40 bias. The USLSTATS code (ORNL 1998) was utilized to perform the statistical analysis and generate an acceptable maximum k{sub eff} limit for calculations of the intermediate enriched uranium type systems.

  13. Optimization of Time-Partitions for Mixed-Criticality Real-Time Distributed Embedded Systems

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Pop, Paul

    2011-01-01

    In this paper we are interested in mixed-criticality embedded real-time applications mapped on distributed heterogeneous architectures. The architecture provides both spatial and temporal partitioning, thus enforcing enough separation for the critical applications. With temporal partitioning, each...

  14. [Analysis of an incident notification system and register in a critical care unit].

    Science.gov (United States)

    Murillo-Pérez, M A; García-Iglesias, M; Palomino-Sánchez, I; Cano Ruiz, G; Cuenca Solanas, M; Alted López, E

    2016-01-01

    To analyse the incident communicated through a notification system and register in a critical care unit. A cross-sectional descriptive study was conducted by performing an analysis of the records of incidents communicated anonymously and voluntarily from January 2007 to December 2013 in a critical care unit of adult patients with severe trauma. incident type and class, professional reports, and suggestions for improvement measures. A descriptive analysis was performed on the variables. Out of a total of 275 incidents reported, 58.5% of them were adverse events. Incident distributed by classes: medication, 33.7%; vascular access-drainage-catheter-sensor, 19.6%; devices-equipment, 13.3%, procedures, 11.5%; airway tract and mechanical ventilation, 10%; nursing care, 4.1%; inter-professional communication, 3%; diagnostic test, 3%; patient identification, 1.1%, and transfusion 0.7%. In the medication group, administrative errors accounted for a total of 62%; in vascular access-drainage-catheter-sensor group, central venous lines, a total of 27%; in devices and equipment group, respirators, a total of 46.9%; in airway self-extubations, a total of 32.1%. As regards to medication errors, 62% were incidents without damage. Incident notification by profession: doctors, 43%, residents, 5.6%, nurses, 51%, and technical assistants, 0.4%. Adverse events are the most communicated incidents. The events related to medication administration are the most frequent, although most of them were without damage. Nurses and doctors communicate the incidents with the same frequency. In order to highlight the low incident notification despite it being an anonymous and volunteer system, therefore, it is suggested to study measurements to increase the level of communication. Copyright © 2016 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  15. The brain as a complex system: plasticity at multiple scales and criticality

    Science.gov (United States)

    Ng, Tony; Miller, Paul

    2015-03-01

    As a complex system, a successful organism is one that can react effectively to environmental fluctuations. Not only should its response repertoire be commensurate with the number of independent conditions that it encounters, behavioral and environmental variations need to be matched at the appropriate scales. In the cortex, neuronal clusters, not individual cells, operate at the proper scale that is necessary to generate appropriate responses to external states of the world. Single neurons, however, serve on a finer scale to mediate interactions between neuronal assemblies. The distinction of scales is significant, as plasticity mechanisms can operate on various spatial and temporal scales. The brain has apparently evolved complex-system strategies to calibrate its own dynamics at multiple scales. This makes the joint study of local balance and global homeostasis fundamentally important, where criticality emerges as a signature of a computationally powerful system. We show via simulations how plasticity mechanisms at multiple scales are inextricably tied to spike-based neuronal avalanches, which are microscopic in origin and poorly predictive of animal behavior, and cluster-based avalanches, which are manifest macroscopically and are relevant to cognition and behavior.

  16. Nuclear criticality safety and time reactivity enhancement aspects of energy amplifier system devices

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, F. [ENEA, Centro Ricerche Trisaia, Rotondelle, Matera (Italy). Direzione INFO

    1995-12-01

    As far as the Rubbia`s and colleagues proposal of innovating Energy Amplifier system (E.A.s.) device driven by a particle beam accelerator is concerned, four basic topics are comprised in the present paper: (1) A short outline of the nuclear aspects of Th-U and U-Pu fuel cycles regarding their general breeding and efficiency features. (2) The needed nuclear criticality control requirements have been studied in terms of safety regulating parameters on the basis of the ThO2 mixed oxides selected as fuel kind for the E.A.s. device technology development. Particular attention is devoted to time evolution of neutron multiplication factor since delayed development of the 233U buildup and so system reactivity are expected in the Th-U cycle. (3) Code E.A.s. device irradiation and post-irradiation modelling for determining higher actinides buildup, fission products formation and fuel consumption trends as function of time, system enrichment degree and flux level parameters. (4) The confirmation, on the basis of the same specific power irradiation, of expected actinides waste obtainment cleaner than the one deriving from the U-Pu cycle utilization. For this end, a model comparison of equivalent enriched fissile nuclides in both cycles has been devised as having, within the range of 0-700 days, ten irradiation periods of about 53 MW/ton specific power and equivalent cooling time post-irradiation periods.

  17. Risk Management method to ERP systems implementation based os critical sucess factors

    Directory of Open Access Journals (Sweden)

    Márcio Saez Caputo

    2004-10-01

    Full Text Available From the second half of years 90, the Enterprise Resource Planning (ERP systems implementation appears like one of the main investment focus related to the use of information technology in the companies, which aimed to acquire competitive advantages through cost reduction and differentiation of products with the use of these systems. ERP implementation showed to be much more than a technology project, involving structural and managing changes, becoming a complex and high risk process for the organizations. In the literature specialized on ERP, there are many examples of the difficulties of this type of project and about implementations that had not reached the expected objectives, frustrating the expectations of the contractors. The present work describes, first of all, the development of a risk management method to ERP systems implementation, based on critical success factors. Then, a case of application of the considered method is analyzed, detailing the steps and the results gotten until the moment. To the end, evidences regarding to how the method helps to improve risk management during ERP implementations are presented.

  18. The endocannabinoid system in critical neurodevelopmental periods: sex differences and neuropsychiatric implications.

    Science.gov (United States)

    Viveros, M P; Llorente, R; Suarez, J; Llorente-Berzal, A; López-Gallardo, M; de Fonseca, F Rodriguez

    2012-01-01

    This review focuses on the endocannabinoid system as a crucial player during critical periods of brain development, and how its disturbance either by early life stressful events or cannabis consumption may lead to important neuropsychiatric signs and symptoms. First we discuss the advantages and limitations of animal models within the framework of neuropsychiatric research and the crucial role of genetic and environmental factors for the establishment of vulnerable phenotypes. We are becoming aware of important sex differences that have emerged in relation to the psychobiology of cannabinoids. We will discuss sexual dimorphisms observed within the endogenous cannabinoid system, as well as those observed with exogenously administered cannabinoids. We start with how the expression of cannabinoid CB(1) receptors is regulated throughout development. Then, we discuss recent results showing how an experimental model of early maternal deprivation, which induces long-term neuropsychiatric symptoms, interacts in a sex-dependent manner with the brain endocannabinoid system during development. This is followed by a discussion of differential vulnerability to the pathological sequelae stemming from cannabinoid exposure during adolescence. Next we talk about sex differences in the interactions between cannabinoids and other drugs of abuse. Finally, we discuss the potential implications that organizational and activational actions of gonadal steroids may have in establishing and maintaining sex dependence in the neurobiological actions of cannabinoids and their interaction with stress.

  19. Structural identifiability of systems biology models: a critical comparison of methods.

    Directory of Open Access Journals (Sweden)

    Oana-Teodora Chis

    Full Text Available Analysing the properties of a biological system through in silico experimentation requires a satisfactory mathematical representation of the system including accurate values of the model parameters. Fortunately, modern experimental techniques allow obtaining time-series data of appropriate quality which may then be used to estimate unknown parameters. However, in many cases, a subset of those parameters may not be uniquely estimated, independently of the experimental data available or the numerical techniques used for estimation. This lack of identifiability is related to the structure of the model, i.e. the system dynamics plus the observation function. Despite the interest in knowing a priori whether there is any chance of uniquely estimating all model unknown parameters, the structural identifiability analysis for general non-linear dynamic models is still an open question. There is no method amenable to every model, thus at some point we have to face the selection of one of the possibilities. This work presents a critical comparison of the currently available techniques. To this end, we perform the structural identifiability analysis of a collection of biological models. The results reveal that the generating series approach, in combination with identifiability tableaus, offers the most advantageous compromise among range of applicability, computational complexity and information provided.

  20. Edge states in the climate system: exploring global instabilities and critical transitions

    Science.gov (United States)

    Lucarini, Valerio; Bódai, Tamás

    2017-07-01

    Multistability is a ubiquitous feature in systems of geophysical relevance and provides key challenges for our ability to predict a system’s response to perturbations. Near critical transitions small causes can lead to large effects and—for all practical purposes—irreversible changes in the properties of the system. As is well known, the Earth climate is multistable: present astronomical and astrophysical conditions support two stable regimes, the warm climate we live in, and a snowball climate characterized by global glaciation. We first provide an overview of methods and ideas relevant for studying the climate response to forcings and focus on the properties of critical transitions in the context of both stochastic and deterministic dynamics, and assess strengths and weaknesses of simplified approaches to the problem. Following an idea developed by Eckhardt and collaborators for the investigation of multistable turbulent fluid dynamical systems, we study the global instability giving rise to the snowball/warm multistability in the climate system by identifying the climatic edge state, a saddle embedded in the boundary between the two basins of attraction of the stable climates. The edge state attracts initial conditions belonging to such a boundary and, while being defined by the deterministic dynamics, is the gate facilitating noise-induced transitions between competing attractors. We use a simplified yet Earth-like intermediate complexity climate model constructed by coupling a primitive equations model of the atmosphere with a simple diffusive ocean. We refer to the climatic edge states as Melancholia states and provide an extensive analysis of their features. We study their dynamics, their symmetry properties, and we follow a complex set of bifurcations. We find situations where the Melancholia state has chaotic dynamics. In these cases, we have that the basin boundary between the two basins of attraction is a strange geometric set with a nearly zero

  1. A method for critical software event execution reliability in high assurance systems

    Energy Technology Data Exchange (ETDEWEB)

    Kidd, M.E.C.

    1997-03-01

    This paper presents a method for Critical Software Event Execution Reliability (Critical SEER). The Critical SEER method is intended for high assurance software that operates in an environment where transient upsets could occur, causing a disturbance of the critical software event execution order, which could cause safety or security hazards. The method has a finite automata based module that watches (hence SEER) and tracks the critical events and ensures they occur in the proper order or else a fail safe state is forced. This method is applied during the analysis, design and implementation phases of software engineering.

  2. Critical success factors for the implementation of information system: a study case from the perspective of a systems integrator firm

    Directory of Open Access Journals (Sweden)

    Eduardo Belmonte Möller

    2014-11-01

    Full Text Available Implementation is one of the critical phases for information systems (IS success. There are several criteria that define IS implementation success. There are also several critical success factors (CSF that influence overall IS success. These criteria and success factors are usually studied in a dispersed way in academic literature. So, there is a need for a deeper understanding of success criteria and CSF, especially during the implementation phase. Therefore, this paper aims to define which are the main success criteria and the main CSF in IS implantation. To this aim, this paper presents a detailed case study from the perspective of IS integrator. To analyze the criteria and success factors involved in IS implementation, a classification framework based on the sociotechnical approach was used and relationship matrices were developed for the subsequent analysis. As result, this paper presents 14 main criteria to evaluate IS implementation success and 31 CSF that contribute to implementation success. Results also present a tentative prioritization of these factors and CSF, as well as an explanatory model that accounts for the relationships between success criteria and CSF.

  3. Sustainability from the Occurrence of Critical Dynamic Power System Blackout Determined by Using the Stochastic Event Tree Technique

    Directory of Open Access Journals (Sweden)

    Muhammad Murtadha Othman

    2017-06-01

    Full Text Available With the advent of advanced technology in smart grid, the implementation of renewable energy in a stressed and complicated power system operation, aggravated by a competitive electricity market and critical system contingencies, this will inflict higher probabilities of the occurrence of a severe dynamic power system blackout. This paper presents the proposed stochastic event tree technique used to assess the sustainability against the occurrence of dynamic power system blackout emanating from implication of critical system contingencies such as the rapid increase in total loading condition and sensitive initial transmission line tripping. An extensive analysis of dynamic power system blackout has been carried out in a case study of the following power systems: IEEE RTS-79 and IEEE RTS-96. The findings have shown that the total loading conditions and sensitive transmission lines need to be given full attention by the utility to prevent the occurrence of dynamic power system blackout.

  4. Fair equality of opportunity critically reexamined: the family and the sustainability of health care systems.

    Science.gov (United States)

    Engelhardt, H Tristram

    2012-12-01

    A complex interaction of ideological, financial, social, and moral factors makes the financial sustainability of health care systems a challenge across the world. One difficulty is that some of the moral commitments of some health care systems collide with reality. In particular, commitments to equality in access to health care and to fair equality of opportunity undergird an unachievable promise, namely, to provide all with the best of basic health care. In addition, commitments to fair equality of opportunity are in tension with the existence of families, because families are aimed at advantaging their own members in preference to others. Because the social-democratic state is committed to fair equality of opportunity, it offers a web of publicly funded entitlements that make it easier for persons to exit the family and to have children outside of marriage. In the United States, in 2008, 41% of children were born outside of wedlock, whereas, in 1940, the percentage was only 3.8%, and in 1960, 5%, with the further consequence that the social and financial capital generated through families, which aids in supporting health care in families, is diminished. In order to explore the challenge of creating a sustainable health care system that also supports the traditional family, the claims made for fair equality of opportunity in health care are critically reconsidered. This is done by engaging the expository device of John Rawls's original position, but with a thin theory of the good that is substantively different from that of Rawls, one that supports a health care system built around significant copayments, financial counseling, and compulsory savings, with a special focus on enhancing the financial and social capital of the family. This radical recasting of Rawls, which draws inspiration from Singapore, is undertaken as a heuristic to aid in articulating an approach to health care allocation that can lead past the difficulties of social-democratic policy.

  5. Landau-like theory for universality of critical exponents in quasistationary states of isolated mean-field systems

    Science.gov (United States)

    Ogawa, Shun; Yamaguchi, Yoshiyuki Y.

    2015-06-01

    An external force dynamically drives an isolated mean-field Hamiltonian system to a long-lasting quasistationary state, whose lifetime increases with population of the system. For second order phase transitions in quasistationary states, two nonclassical critical exponents have been reported individually by using a linear and a nonlinear response theories in a toy model. We provide a simple way to compute the critical exponents all at once, which is an analog of the Landau theory. The present theory extends the universality class of the nonclassical exponents to spatially periodic one-dimensional systems and shows that the exponents satisfy a classical scaling relation inevitably by using a key scaling of momentum.

  6. Landau-like theory for universality of critical exponents in quasistationary states of isolated mean-field systems.

    Science.gov (United States)

    Ogawa, Shun; Yamaguchi, Yoshiyuki Y

    2015-06-01

    An external force dynamically drives an isolated mean-field Hamiltonian system to a long-lasting quasistationary state, whose lifetime increases with population of the system. For second order phase transitions in quasistationary states, two nonclassical critical exponents have been reported individually by using a linear and a nonlinear response theories in a toy model. We provide a simple way to compute the critical exponents all at once, which is an analog of the Landau theory. The present theory extends the universality class of the nonclassical exponents to spatially periodic one-dimensional systems and shows that the exponents satisfy a classical scaling relation inevitably by using a key scaling of momentum.

  7. R\\'enyi entanglement entropies of descendant states in critical systems with boundaries: conformal field theory and spin chains

    CERN Document Server

    Taddia, Luca; Pálmai, Tamás

    2016-01-01

    We discuss the R\\'enyi entanglement entropies of descendant states in critical one-dimensional systems with boundaries, that map to boundary conformal field theories (CFT) in the scaling limit. We unify the previous CFT approaches to describe primary and descendant states in systems with both open and closed boundaries. We apply the technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and compare the results to numerical data obtained on finite spin chains.

  8. STUDENTS’ CRITICAL THINKING IN WRITING A THESIS USING THE TRANSITIVITY SYSTEM

    Directory of Open Access Journals (Sweden)

    Emi Emilia

    2016-02-01

    Full Text Available Abstract: Students’ Critical Thinking in Writing a Thesis Using the Transitivity System. This paper reports on a small part of the results of a study in attempting to identify students’ ability and difficulties in writing an English undergraduate thesis in a state university in Indonesia. The paper centres around the students’ ability and difficulties in writing a data presentation and discussion chapter, which are related to critical capacity looked at in this study. The paper begins with a brief introduction, which presents the background and the theories underpinning the study. This will be followed by an account of the methodology, in which it is argued that the study used a case study method, particularly text analysis  and involved  nine theses  selected randomly and analysed based on the elements of a conventional research report and the Transitivity system of systemic functional grammar, developed by Halliday. The paper then delineates the results, showing that despite their  good control in the discourse semantic level, students in general still need a lot of guidance and assistance in writing a data presentation and discussion chapter. Recommendation for further research will conclude the paper. Abstrak: Kemampuan Berpikir Kritis Mahasiswa dalam Menulis Tesis. Artikel ini membahas sebagian hasil penelitian yang berupaya untuk mengidentifikasi kemampuan dan kesulitan mahasiswa dalam menulis skripsi. Pembahasan difokuskan pada kemampuan dan kesulitan mahasiswa dalam menulis bab pemaparan dan pembahasan data, yang sangat erat kaitannya dengan kemampuan berpikir kritis. Penelitian ini menggunakan rancangan studi kasus, khususnya analisis teks dan melibatkan 9 skrip yang dipilih secara acak. Data dianalisis berdasarkan struktur organisasi atau elemen-elemen yang seharusnya ada dalam laporan penelitian konvensional dan sistem Transitivity dari tata bahasa sistemik fungsional yang dikembangkan oleh Halliday. Hasil penelitian

  9. The implementation of a Hazard Analysis and Critical Control Point management system in a peanut butter ice cream plant

    OpenAIRE

    2015-01-01

    To ensure the safety of the peanut butter ice cream manufacture, a Hazard Analysis and Critical Control Point (HACCP) plan has been designed and applied to the production process. Potential biological, chemical, and physical hazards in each manufacturing procedure were identified. Critical control points for the peanut butter ice cream were then determined as the pasteurization and freezing process. The establishment of a monitoring system, corrective actions, verification procedures, and doc...

  10. Classification of the sign of the critical Casimir force in two dimensional systems

    CERN Document Server

    Rajabpour, M A

    2016-01-01

    We classify the sign of the critical Casimir force between two finite objects separated by a large distance in the two dimensional systems that can be described by conformal field theory (CFT). In particular, we show that as far as the smallest scaling dimension present in the spectrum of the system is smaller than one, the sign of the force is independent of the shape of the objects and can be determined by the elements of the modular $S$-matrix of the CFT. The provided formula for the sign of the force indicates that the force is always attractive for equal boundary conditions independent of the shape of the objects. However, different boundary conditions can lead to attractive or repulsive forces. Using the derived formula, we prove the known results regarding the Ising model and the free bosons. As new examples, we give detailed results regarding the Q=3-states Potts model and the compactified bosons. In particular, for the latter model we show that Dirichlet boundary condition does not always lead to an ...

  11. Critical micelle concentration of surfactants in aqueous buffered and unbuffered systems

    Energy Technology Data Exchange (ETDEWEB)

    Fuguet, Elisabet [Departament de Quimica Analitica, Universitat de Barcelona, Facultat de Quimica, Marti i Franques 1-11, 08028 Barcelona (Spain); Rafols, Clara [Departament de Quimica Analitica, Universitat de Barcelona, Facultat de Quimica, Marti i Franques 1-11, 08028 Barcelona (Spain); Roses, Marti [Departament de Quimica Analitica, Universitat de Barcelona, Facultat de Quimica, Marti i Franques 1-11, 08028 Barcelona (Spain); Bosch, Elisabeth [Departament de Quimica Analitica, Universitat de Barcelona, Facultat de Quimica, Marti i Franques 1-11, 08028 Barcelona (Spain)]. E-mail: e.bosch@ub.edu

    2005-08-29

    Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), lithium perfluorooctanesulfonate (LPFOS), hexadecyltrimethylammonium bromide (HTAB), tetradecyltrimethylammonium bromide (TTAB), and sodium cholate (SC), surfactants commonly used as pseudostationary phases in micellar electrokinetic chromatography (MEKC), have been determined by means of three different methods: MEKC, spectrophotometry, and conductometry. Determinations have been performed in water, and also in different concentrations of phosphate buffer at pH 7.0. CMC values ranging from 8.08 (water) to 1.99 (50 mM phosphate buffer) mM for SDS, from 7.16 (water) to 2,81 (30 mM phosphate buffer) mM for LPFOS, from 3.77 (water) to 1.93 (20 mM phosphate buffer) mM for TTAB, from 0.91 (water) to {approx}0.34 (20 mM phosphate buffer) for HTAB, and around 13 mM (20 mM phosphate buffer) for SC, are obtained. The effect of the electrolyte concentration on the CMC, as well as the linear relationship between the electrolyte counter-ion concentration and the CMC are discussed. This linear relationship provides an easy way for users to estimate the CMC of a MEKC system, at a given electrolyte concentration. A comparison between experimental methods, as well as a discussion about the suitability of a given method for the determination of the CMC for a given surfactant system is also provided.

  12. External Thermal Insulation Composite Systems: Critical Parameters for Surface Hygrothermal Behaviour

    Directory of Open Access Journals (Sweden)

    Eva Barreira

    2014-01-01

    Full Text Available External Thermal Insulation Composite Systems (ETICS are often used in Europe. Despite its thermal advantages, low cost, and ease of application, this system has serious problems of biological growth causing the cladding defacement. Recent studies pointed that biological growth is due to high values of surface moisture content, which mostly results from the combined effect of exterior surface condensation, wind-driven rain, and drying process. Based on numerical simulation, this paper points the most critical parameters involved in hygrothermal behaviour of ETICS, considering the influence of thermal and hygric properties of the external rendering, the effect of the characteristics of the façade, and the consequences of the exterior and interior climate on exterior surface condensation, wind-driven rain, and drying process. The model used was previously validated by comparison with the results of an “in situ” campaign. The results of the sensitivity analyses show that relative humidity and temperature of the exterior air, atmospheric radiation, and emissivity of the exterior rendering are the parameters that most influence exterior surface condensation. Wind-driven rain depends mostly on horizontal rain, building’s height, wind velocity, and orientation. The drying capacity is influenced by short-wave absorbance, incident solar radiation, and orientation.

  13. Scoring System Approach for Assessment of Critical Illness using Mobile Phones

    Directory of Open Access Journals (Sweden)

    Karupothula Madhavi Latha

    2012-02-01

    Full Text Available This paper demonstrates the use of mobile phones in assessing the illness of patients by developing a Scoring Systemwhere medical practitioners (often nurses collect various physiological signals like ECG, EEG, SpO2, temperature, continuous blood pressure and subjective parameters like level of pain, level of alertness, awareness, behavioral responses etc. After taking the data, a scoring system is utilized for early detection of critical illnesses. The mechanism of scoring is performed either manually, where the medical practitioner ticks on to a scoring board or is automated by relocating the information from scoring board to a PC, where the software performs the scoring calculation. In the proposed system, the medical practitioner inputs the parameters directly on to their mobile phone by collecting the parameters fromthe patient. The score is automatically calculated by miniature java based software running inside themobile phone. Based on the score, level of urgency is determined by the intelligent program. At the end, specialists are contacted automatically by messaging services. Moreover, the results of the scoring are transmitted to the hospital server. Therefore, assistance from civilians with mobile phone based medical intelligence can save precious life.

  14. CYTOKINE RESPONSE AND OTHER DIFFERENCES BETWEEN CRITICAL PHASES OF SEPSIS-ASSOCIATED SYSTEMIC INFLAMMATION

    Directory of Open Access Journals (Sweden)

    E. Yu. Gusev

    2014-01-01

    Full Text Available Acute sepsis (1-3 days after admission has been compared with tertiary peritonitis, as a clinical variant of prolonged sepsis (7 to 42 days after admission. A total of 153 patients were enrolled into the study, including 112 cases of multiple organ dysfunction syndrome (MODS, as assessed by SOFA score, of them thirty-one with septic shock; fatal outcomes, in 48 cases. Plasma concentrations of C-reactive protein, cytokines (IL-6, IL-8, IL-10, TNFα, cortisol, troponin I, myoglobin, D-dimer were detected by means of immunochemiluminesce assay (ImmuLite. Development of systemic inflammation (SI was evaluated by appropriate integral criteria. An association was established between SI development and critical complications in the both groups of patients. Meanwhile, hyperergic variants of SI development associated with high cytokine levels, proved to prevail in acute sepsis. On the contrary, hypoergic variants were more common in cases of tertiary peritonitis, being characterized by relatively low levels of cytokines, along with higher probability of other SI syndromes and risks of lethal outcomes. In summary, systemic inflammatory events in acute versus prolonged sepsis may proceed by different pathogenetic pathways.

  15. Liposome Delivery Systems for Inhalation: A Critical Review Highlighting Formulation Issues and Anticancer Applications.

    Science.gov (United States)

    Rudokas, Mindaugas; Najlah, Mohammad; Alhnan, Mohamed Albed; Elhissi, Abdelbary

    2016-01-01

    This is a critical review on research conducted in the field of pulmonary delivery of liposomes. Issues relating to the mechanism of nebulisation and liposome composition were appraised and correlated with literature reports of liposome formulations used in clinical trials to understand the role of liposome size and composition on therapeutic outcome. A major highlight was liposome inhalation for the treatment of lung cancers. Many in vivo studies that explored the potential of liposomes as anticancer carrier systems were evaluated, including animal studies and clinical trials. Liposomes can entrap anticancer drugs and localise their action in the lung following pulmonary delivery. The safety of inhaled liposomes incorporating anticancer drugs depends on the anticancer agent used and the amount of drug delivered to the target cancer in the lung. The difficulty of efficient targeting of liposomal anticancer aerosols to the cancerous tissues within the lung may result in low doses reaching the target site. Overall, following the success of liposomes as inhalable carriers in the treatment of lung infections, it is expected that more focus from research and development will be given to designing inhalable liposome carriers for the treatment of other lung diseases, including pulmonary cancers. The successful development of anticancer liposomes for inhalation may depend on the future development of effective aerosolisation devices and better targeted liposomes to maximise the benefit of therapy and reduce the potential for local and systemic adverse effects.

  16. Research on the critical parameters initialization of optical PMD compensator in high bit-rate systems

    Science.gov (United States)

    Zhao, Wenyu; Zhang, Haiyi; Ji, Yuefeng; Xu, Daxiong

    2004-05-01

    Based on the proposed polarization mode dispersion (PMD) compensation simulation model and statistical analysis method (Monte-Carlo), the critical parameters initialization of two typical optical domain PMD compensators, which include optical PMD method with fixed compensation differential group delay (DGD) and that with variable compensation DGD, are detailedly investigated by numerical method. In the simulation, the line PMD values are chosen as 3ps, 4ps and 5ps and run samples are set to 1000 in order to achieve statistical evaluation for PMD compensated systems, respectively. The simulation results show that for the PMD value pre-known systems, the value of the fixed DGD compensator should be set to 1.5~1.6 times of line PMD value in order to reach the optimum performance, but for the second kind of PMD compensator, the DGD range of lower limit should be 1.5~1.6 times of line PMD provided that of upper limit is set to 3 times of line PMD, if no effective ways are chosen to resolve the problem of local minimum in optimum process. Another conclusion can be drawn from the simulation is that, although the second PMD compensator holds higher PMD compensation performance, it will spend more feedback loops to look up the optimum DGD value in the real PMD compensation realization, and this will bring more requirements on adjustable DGD device, not only wider adjustable range, but rapid adjusting speed for real time PMD equalization.

  17. Critical transitions of stratocumulus dynamical systems due to perturbation in free-atmosphere moisture

    Science.gov (United States)

    Tsai, Jia-Ying; Wu, Chien-Ming

    2016-12-01

    The bi-stable behavior of stratocumulus systems is here investigated in a 3D cloud-resolving model based on vector vorticity equations (VVM). This study demonstrates the response of the stratocumulus system to small perturbations of free atmospheric moisture under specified forcings of warm sea surface temperature (SST) and weak subsidence. A critical transition, indicated by the strong decoupling and large variation of cloud properties, separates fast dynamics from slow dynamics. During the fast process governed by the thermodynamic adjustment, the liquid water path (LWP) decreases with a decreasing cloud-top entrainment rate; on the other hand, during the slow process determined by the cloud-top inversion adjustment, LWP increases. The model exhibits two coexisting (cloudy and non-cloudy) quasi-stationary states through the fast process. A key process for the bifurcation is that the non-cloudy state shows the presence of active cumulus convection that allows the destruction of stratocumulus. The results suggest that the direct entrainment drying is enhanced due to an increased moisture gradient across the inversion layer. This tends to develop more broken clouds, which is an important signal for the stratocumulus to cumulus transition. This conceptual model provides a simple framework for developing a timely switch of regime transition in the cloud parameterization in large-scale models.

  18. A critical review on the consensus around the «Westphalian system»

    Directory of Open Access Journals (Sweden)

    Luís Moita

    2012-01-01

    Full Text Available The Thirty Years’ War, which devastated Europe between 1618 and 1648, was a complex conflict: it was a religious war; it involved the main powers of the time, dynasty rivalries and rebellions from princes against the Emperor of the Holy Roman-German Empire. There is a consensus in viewing the Peace of Westphalia, which ended the war, as a decisive moment in the history of international relations and the majority of authors considers it the starting point of the modern State-Nation system, sovereign states which have jurisdiction over a territory, which were usually secular and related to one another according to the principle of the balance of power. A critical review of this consensus leads to question each of the above mentioned topics and conclude that the common interpretation has retrospectively transposed political processes which took place only later. In fact, it is likely that, in the 17th century, the pre-modern princely State is still dominant, which will then lead to the modern State-Nation system, a consequence of the emergence of industrial society and nationalism. One may even consider that the Peace of Westphalia delayed the constitution of national States, as far as Germany is concerned. Therefore, to use the terms “Westphalian state” and “Westphalian system” seems rather unadvisable.

  19. A Critical Analysis of the Use of MCE Systems with Deaf Students: A Review of the Literature.

    Science.gov (United States)

    Drasgow, Erik; Paul, Peter V.

    1995-01-01

    This article presents a critical evaluation of the use of Pidgin Signed English (PSE) and three manually coded English (MCE) systems, signed English, Seeing Essential English, and Signing Exact English with deaf students. It concludes that the use of MCE systems is unlikely to result in English proficiency for many students with severe to profound…

  20. Criticality Model

    Energy Technology Data Exchange (ETDEWEB)

    A. Alsaed

    2004-09-14

    this analysis is to document the criticality computational method. The criticality computational method will be used for evaluating the criticality potential of configurations of fissionable materials (in-package and external to the waste package) within the repository at Yucca Mountain, Nevada for all waste packages/waste forms. The criticality computational method is also applicable to preclosure configurations. The criticality computational method is a component of the methodology presented in ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). How the criticality computational method fits in the overall disposal criticality analysis methodology is illustrated in Figure 1 (YMP 2003, Figure 3). This calculation will not provide direct input to the total system performance assessment for license application. It is to be used as necessary to determine the criticality potential of configuration classes as determined by the configuration probability analysis of the configuration generator model (BSC 2003a).

  1. A critical review of interfaces with the peripheral nervous system for the control of neuroprostheses and hybrid bionic systems.

    Science.gov (United States)

    Navarro, Xavier; Krueger, Thilo B; Lago, Natalia; Micera, Silvestro; Stieglitz, Thomas; Dario, Paolo

    2005-09-01

    Considerable scientific and technological efforts have been devoted to develop neuroprostheses and hybrid bionic systems that link the human nervous system with electronic or robotic prostheses, with the main aim of restoring motor and sensory functions in disabled patients. A number of neuroprostheses use interfaces with peripheral nerves or muscles for neuromuscular stimulation and signal recording. Herein, we provide a critical overview of the peripheral interfaces available and trace their use from research to clinical application in controlling artificial and robotic prostheses. The first section reviews the different types of non-invasive and invasive electrodes, which include surface and muscular electrodes that can record EMG signals from and stimulate the underlying or implanted muscles. Extraneural electrodes, such as cuff and epineurial electrodes, provide simultaneous interface with many axons in the nerve, whereas intrafascicular, penetrating, and regenerative electrodes may contact small groups of axons within a nerve fascicle. Biological, technological, and material science issues are also reviewed relative to the problems of electrode design and tissue injury. The last section reviews different strategies for the use of information recorded from peripheral interfaces and the current state of control neuroprostheses and hybrid bionic systems.

  2. A Return to Innovative Engineering Design, Critical Thinking and Systems Engineering

    Science.gov (United States)

    Camarda, Charles J.

    2007-01-01

    I believe we are facing a critical time where innovative engineering design is of paramount importance to the success of our aerospace industry. However, the very qualities and attributes necessary for enhancing, educating, and mentoring a creative spirit are in decline in important areas. The importance of creativity and innovation in this country was emphasized by a special edition of the Harvard Business Review OnPoint entitled: "The Creative Company" which compiled a series of past and present articles on the subject of creativity and innovation and stressed its importance to our national economy. There is also a recognition of a lack of engineering, critical thinking and problem-solving skills in our education systems and a trend toward trying to enhance those skills by developing K-12 educational programs such as Project Lead the Way, "Science for All Americans", Benchmarks 2061 , etc. In addition, with respect to spacecraft development, we have a growing need for young to mid-level engineers with appropriate experience and skills in spacecraft design, development, analysis, testing, and systems engineering. As the Director of Engineering at NASA's Johnson Space Center, I realized that sustaining engineering support of an operational human spacecraft such as the Space Shuttle is decidedly different than engineering design and development skills necessary for designing a new spacecraft such as the Crew Exploration Vehicle of the Constellation Program. We learned a very important lesson post Columbia in that the Space Shuttle is truly an experimental and not an operational vehicle and the strict adherence to developed rules and processes and chains of command of an inherently bureaucratic organizational structure will not protect us from a host of known unknowns let alone unknown unknowns. There are no strict rules, processes, or procedures for understanding anomalous results of an experiment, anomalies with an experimental spacecraft like Shuttle, or in the

  3. Determination of the critical micelle concentration in simulations of surfactant systems

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Andrew P.; Panagiotopoulos, Athanassios Z., E-mail: azp@princeton.edu [Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-01-28

    Alternative methods for determining the critical micelle concentration (cmc) are investigated using canonical and grand canonical Monte Carlo simulations of a lattice surfactant model. A common measure of the cmc is the “free” (unassociated) surfactant concentration in the presence of micellar aggregates. Many prior simulations of micellizing systems have observed a decrease in the free surfactant concentration with overall surfactant loading for both ionic and nonionic surfactants, contrary to theoretical expectations from mass-action models of aggregation. In the present study, we investigate a simple lattice nonionic surfactant model in implicit solvent, for which highly reproducible simulations are possible in both the canonical (NVT) and grand canonical (μVT) ensembles. We confirm the previously observed decrease of free surfactant concentration at higher overall loadings and propose an algorithm for the precise calculation of the excluded volume and effective concentration of unassociated surfactant molecules in the accessible volume of the solution. We find that the cmc can be obtained by correcting the free surfactant concentration for volume exclusion effects resulting from the presence of micellar aggregates. We also develop an improved method for determination of the cmc based on the maximum in curvature for the osmotic pressure curve determined from μVT simulations. Excellent agreement in cmc and other micellar properties between NVT and μVT simulations of different system sizes is observed. The methodological developments in this work are broadly applicable to simulations of aggregating systems using any type of surfactant model (atomistic/coarse grained) or solvent description (explicit/implicit)

  4. Agile hardware and software systems engineering for critical military space applications

    Science.gov (United States)

    Huang, Philip M.; Knuth, Andrew A.; Krueger, Robert O.; Garrison-Darrin, Margaret A.

    2012-06-01

    The Multi Mission Bus Demonstrator (MBD) is a successful demonstration of agile program management and system engineering in a high risk technology application where utilizing and implementing new, untraditional development strategies were necessary. MBD produced two fully functioning spacecraft for a military/DOD application in a record breaking time frame and at dramatically reduced costs. This paper discloses the adaptation and application of concepts developed in agile software engineering to hardware product and system development for critical military applications. This challenging spacecraft did not use existing key technology (heritage hardware) and created a large paradigm shift from traditional spacecraft development. The insertion of new technologies and methods in space hardware has long been a problem due to long build times, the desire to use heritage hardware, and lack of effective process. The role of momentum in the innovative process can be exploited to tackle ongoing technology disruptions and allowing risk interactions to be mitigated in a disciplined manner. Examples of how these concepts were used during the MBD program will be delineated. Maintaining project momentum was essential to assess the constant non recurring technological challenges which needed to be retired rapidly from the engineering risk liens. Development never slowed due to tactical assessment of the hardware with the adoption of the SCRUM technique. We adapted this concept as a representation of mitigation of technical risk while allowing for design freeze later in the program's development cycle. By using Agile Systems Engineering and Management techniques which enabled decisive action, the product development momentum effectively was used to produce two novel space vehicles in a fraction of time with dramatically reduced cost.

  5. A Critical Appraisal of the Juvenile Justice System under Cameroon's 2005 Criminal Procedure Code: Emerging Challenges

    Directory of Open Access Journals (Sweden)

    S Tabe

    2012-03-01

    Full Text Available The objective of this article is to examine the changes introduced by the 2005 Cameroonian Criminal Procedure Code on matters of juvenile justice, considering that before this Code, juvenile justice in Cameroon was governed by extra-national laws. In undertaking this analysis, the article highlights the evolution of the administration of juvenile justice 50 years after independence of Cameroon. It also points out the various difficulties and shortcomings in the treatment of juvenile offenders in Cameroon since the enactment of the new Criminal Procedure Code. The article reveals that the 2005 Code is an amalgamation of all hitherto existing laws in the country that pertained to juvenile justice, and that despite the considerable amount of criticism it has received, the Code is clearly an improvement of the system of juvenile justice in Cameroon, since it represents a balance of the due process rights of young people, the protection of society and the special needs of young offenders. This is so because the drafters of the Code took a broad view of the old laws on juvenile justice. Also a wide range of groups were consulted, including criminal justice professionals, children’s service organisations, victims, parents, young offenders, educators, advocacy groups and social-policy analysts. However, to address the challenges that beset the juvenile justice system of Cameroon, the strategy of the government should be focussed on three areas: the prevention of youth crime, the provision of meaningful consequences for the actions of young people, and the rehabilitation and reintegration of young offenders. Cameroonian law should seek educative solutions rather than to impose prison sentences or other repressive measures on young offenders. Special courts to deal with young offenders should be established outside the regular penal system and should be provided with resources that are adequate for and appropriate to fostering their understanding of

  6. Oxidative stress and immune system analysis after cycle ergometer use in critical patients

    Science.gov (United States)

    de França, Eduardo Eriko Tenório; Ribeiro, Luana Carneiro; Lamenha, Gabriela Gomes; Magalhães, Isabela Kalline Fidelix; de Gomes Figueiredo, Thainá; Costa, Marthley José Correia; Júnior, Ubiracé Fernando Elihimas; Feitosa, Bárbara Luana; do Amparo Andrade, Maria; Júnior, Marco Aurélio Valois Correia; Ramos, Francimar Ferrari; de Castro, Célia Maria Machado Barbosa

    2017-01-01

    OBJECTIVE: The passive cycle ergometer aims to prevent hypotrophy and improve muscle strength, with a consequent reduction in hospitalization time in the intensive care unit and functional improvement. However, its effects on oxidative stress and immune system parameters remain unknown. The aim of this study is to analyze the effects of a passive cycle ergometer on the immune system and oxidative stress in critical patients. METHODS: This paper describes a randomized controlled trial in a sample of 19 patients of both genders who were on mechanical ventilation and hospitalized in the intensive care unit of the Hospital Agamenom Magalhães. The patients were divided into two groups: one group underwent cycle ergometer passive exercise for 30 cycles/min on the lower limbs for 20 minutes; the other group did not undergo any therapeutic intervention during the study and served as the control group. A total of 20 ml of blood was analysed, in which nitric oxide levels and some specific inflammatory cytokines (tumour necrosis factor alpha (TNF-α), interferon gamma (IFN-γ) and interleukins 6 (IL-6) and 10 (IL-10)) were evaluated before and after the study protocol. RESULTS: Regarding the demographic and clinical variables, the groups were homogeneous in the early phases of the study. The nitric oxide analysis revealed a reduction in nitric oxide variation in stimulated cells (p=0.0021) and those stimulated (p=0.0076) after passive cycle ergometer use compared to the control group. No differences in the evaluated inflammatory cytokines were observed between the two groups. CONCLUSION: We can conclude that the passive cycle ergometer promoted reduced levels of nitric oxide, showing beneficial effects on oxidative stress reduction. As assessed by inflammatory cytokines, the treatment was not associated with changes in the immune system. However, further research in a larger population is necessary for more conclusive results. PMID:28355359

  7. Critical role of GFRα1 in the development and function of the main olfactory system.

    Science.gov (United States)

    Marks, Carolyn; Belluscio, Leonardo; Ibáñez, Carlos F

    2012-11-28

    Glial cell line-derived neurotrophic factor (GDNF) and its receptor GFRα1 are prominently expressed in the olfactory epithelium (OE) and olfactory bulb (OB), but their importance for olfactory system development is completely unknown. We have investigated the consequences of GFRα1 deficiency for mouse olfactory system development and function. In the OE, GFRα1 was expressed in basal precursors, immature olfactory sensory neurons (OSNs), and olfactory ensheathing cells (OECs), but was excluded from mature OSNs. The OE of newborn Gfra1 knock-out mice was thinner and contained fewer OSNs, but more dividing precursors, suggesting deficient neurogenesis. Immature OSN axon bundles were enlarged and associated OECs increased, indicating impaired migration of OECs and OSN axons. In the OB, GFRα1 was expressed in immature OSN axons and OECs of the nerve layer, as well as mitral and tufted cells, but was excluded from GABAergic interneurons. In newborn knock-outs, the nerve layer was dramatically reduced, exhibiting fewer axons and OECs. Bulbs were smaller and presented fewer and disorganized glomeruli and a significant reduction in mitral cells. Numbers of tyrosine hydroxylase-, calbindin-, and calretinin-expressing interneurons were also reduced in newborn mice lacking Gfra1. At birth, the OE and OB of Gdnf knock-out mice displayed comparable phenotypes. Similar deficits were also found in adult heterozygous Gfra1(+/-) mutants, which in addition displayed diminished responses in behavioral tests of olfactory function. We conclude that GFRα1 is critical for the development and function of the main olfactory system, contributing to the development and allocation of all major classes of neurons and glial cells.

  8. The critical role of epigenetics in systemic lupus erythematosus and autoimmunity.

    Science.gov (United States)

    Long, Hai; Yin, Heng; Wang, Ling; Gershwin, M Eric; Lu, Qianjin

    2016-11-01

    One of the major disappointments in human autoimmunity has been the relative failure on genome-wide association studies to provide "smoking genetic guns" that would explain the critical role of genetic susceptibility to loss of tolerance. It is well known that autoimmunity refers to the abnormal state that the dysregulated immune system attacks the healthy cells and tissues due to the loss of immunological tolerance to self-antigens. Its clinical outcomes are generally characterized by the presence of autoreactive immune cells and (or) the development of autoantibodies, leading to various types of autoimmune disorders. The etiology and pathogenesis of autoimmune diseases are highly complex. Both genetic predisposition and environmental factors such as nutrition, infection, and chemicals are implicated in the pathogenic process of autoimmunity, however, how much and by what mechanisms each of these factors contribute to the development of autoimmunity remain unclear. Epigenetics, which refers to potentially heritable changes in gene expression and function that do not involve alterations of the DNA sequence, has provided us with a brand new key to answer these questions. In the recent decades, increasing evidence have demonstrated the roles of epigenetic dysregulation, including DNA methylation, histone modification, and noncoding RNA, in the pathogenesis of autoimmune diseases, especially systemic lupus erythematosus (SLE), which have shed light on a new era for autoimmunity research. Notably, DNA hypomethylation and reactivation of the inactive X chromosome are two epigenetic hallmarks of SLE. We will herein discuss briefly how genetic studies fail to completely elucidate the pathogenesis of autoimmune diseases and present a comprehensive review on landmark epigenetic findings in autoimmune diseases, taking SLE as an extensively studied example. The epigenetics of other autoimmune diseases such as rheumatic arthritis, systemic sclerosis and primary biliary

  9. Mutual Inclusivity of the Critical Path and its Partial Schedule on Heterogeneous Systems

    OpenAIRE

    Vasudevan, Aravind; Gregg, David

    2017-01-01

    The critical path of a group of tasks is an important measure that is commonly used to guide task allocation and scheduling on parallel computers. The critical path is the longest chain of dependencies in an acyclic task dependence graph. A problem arises on heterogeneous parallel machines where computation and communication costs can vary between different types of processor. Existing solutions for heterogeneous machines attempt to estimate the critical path using average values of computati...

  10. Critical fluctuations and noncritical relaxations of the nitrobenzene isooctane system near its consolute point

    Science.gov (United States)

    Khabibullaev, P. K.; Mirzaev, S. Z.; Kaatze, U.

    2008-06-01

    Ultrasonic attenuation spectra between 20 kHz and 3 GHz of the nitrobenzene-isooctane mixture of critical composition have been analyzed to show that they contain noncritical relaxation terms in addition to the critical term. The parameter values of the noncritical contributions obtained thereby are used in a re-evaluation of smallband attenuation data from the literature. These data, measured at a large number of temperatures near the critical, are most suitable for the determination of the scaling function in the critical dynamics. The procedure allows to verify the empirical scaling function of the Bhattacharjee-Ferrell dynamic scaling theory without an adjustable parameter.

  11. Validation of KENO V. a. and two cross-section libraries for criticality calculations of low-enriched uranium systems

    Energy Technology Data Exchange (ETDEWEB)

    Easter, M.E.

    1985-07-01

    The SCALE code system, utilizing the Monte Carlo computer code KENO V.a, was employed to calculate 37 critical experiments. The critical assemblies had /sup 235/U enrichments of 5% or less and cover a variety of geometries and materials. Values of k/sub eff/ were calculated using two different results using either of the cross-section libraries. The 16-energy-group Hansen-Roach and the 27-energy-group ENDF/B-IV cross-section libraries, available in SCALE, were used in this validation study, and both give good results for the experiments considered. It is concluded that the code and cross sections are adequate for low-enriched uranium systems and that reliable criticality safety calculations can be made for such systems provided the limits of validated applicability are not exceeded.

  12. Renyi entanglement entropies of descendant states in critical systems with boundaries: conformal field theory and spin chains

    Science.gov (United States)

    Taddia, Luca; Ortolani, Fabio; Pálmai, Tamás

    2016-09-01

    We discuss the Renyi entanglement entropies of descendant states in critical one-dimensional systems with boundaries, that map to boundary conformal field theories in the scaling limit. We unify the previous conformal-field-theory approaches to describe primary and descendant states in systems with both open and closed boundaries. We provide universal expressions for the first two descendants in the identity family. We apply our technique to critical systems belonging to different universality classes with non-trivial boundary conditions that preserve conformal invariance, and find excellent agreement with numerical results obtained for finite spin chains. We also demonstrate that entanglement entropies are a powerful tool to resolve degeneracy of higher excited states in critical lattice models.

  13. Is Model-Based Development a Favorable Approach for Complex and Safety-Critical Computer Systems on Commercial Aircraft?

    Science.gov (United States)

    Torres-Pomales, Wilfredo

    2014-01-01

    A system is safety-critical if its failure can endanger human life or cause significant damage to property or the environment. State-of-the-art computer systems on commercial aircraft are highly complex, software-intensive, functionally integrated, and network-centric systems of systems. Ensuring that such systems are safe and comply with existing safety regulations is costly and time-consuming as the level of rigor in the development process, especially the validation and verification activities, is determined by considerations of system complexity and safety criticality. A significant degree of care and deep insight into the operational principles of these systems is required to ensure adequate coverage of all design implications relevant to system safety. Model-based development methodologies, methods, tools, and techniques facilitate collaboration and enable the use of common design artifacts among groups dealing with different aspects of the development of a system. This paper examines the application of model-based development to complex and safety-critical aircraft computer systems. Benefits and detriments are identified and an overall assessment of the approach is given.

  14. Electromagnet Response Time Tests on Primary CRDM of a Prototype Gen-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae-Han; Koo, Gyeong-Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    This paper identifies the electromagnetic response characteristics of the electromagnet of a primary control rod drive mechanism (CRDM) used for the reactor scram function. The test measures the electromagnet response time required to release an armature from a stator controlled by a loss of an electromagnetic force on an armature after shorting a power supply to an electromagnet coil. These tests are carried out while changing the electromagnet core material, an assist spring, and an armature holding current. The main factors influencing the test parameters on the response are found to be the armature holding current for holding the armature loads, and the material type of the electromagnet cores. The minimum response time is 0.13 seconds in the case of using SS410 material as an armature, while the S10C material as an armature has a response time of 0.21 seconds. Electromagnet response time characteristics from the test results will be evaluated by comparing the precise moving data of an electromagnet armature through the use of a high-speed camera and a potentiometer in the future.

  15. Preliminary Comparative Evaluation Study on Reference Design of GEN-IV SFR

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Yoon Sub; Kim, Yeong Il; Hong, Ser Gi (and others)

    2005-11-15

    A fast reactor has a good transmutation capability and it enables breeding of fuel and use of a closed fuel cycle. By these characteristics of a fast reactor, the limited uranium resources of the world can be much more effectively utilized and the nuclear wastes of a high level of radioactivity and toxicity from the current nuclear power reactors of LWRs and HWRs can be drastically reduced in its volume and the management of the wastes can be easily treated. Also electricity can be generated more effectively since a fast reactor has the feature of high operation temperature. These features of a fast reactor makes it inevitable on a long term basis to construct fast reactors in Korea. The domestic fast reactor technology level, however, is at the level of coming out of a beginning stage and needs utilization of international expertise. Recently an international cooperation program called GIF has been formulated and our KALIMER was selected as one of the two reference designs for the international joint R and D works with JSFR of Japan. In the current frame of the GIF program, the two selected reference designs are supposed to be evaluated against each other in future and one design is to be finally selected. To make the international cooperation program directed more useful to our fast reactor technology development, it is required to strengthen the competitiveness of KALIMER so that it can be selected. To meet the necessity, a study was made in this research for pre-evaluation of the GIF reference designs and setting up plans for development of designs and technology that will enhance the competitiveness of KALIMER.

  16. Development of the GANEX process for the reprocessing of Gen IV spent nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Miguirditchian, M.; Chareyre, L.; Sorel, C.; Bisel, I.; Baron, P.; Masson, M. [CEA Marcoule - DEN/DRCP/SCPS - BP 17171, Bagnols-sur-Ceze, 30207 (France)

    2008-07-01

    The GANEX (group actinide extraction) process is composed of two extraction cycles following the dissolution of the spent fuel. In the first cycle, uranium(VI) is selectively extracted from the dissolution solution using a mono amide extractant DEHiBA (NN--di-(ethyl-2-hexyl)iso-butyr-amide) diluted in HTP (hydrogen tetra-propylene). Experimental data and modelling of uranium(VI) and nitric acid extractions are presented. A flowsheet was designed and was successfully tested in laboratory scale mixer-settlers on a surrogate uranium(VI)/HNO{sub 3} feed. For the group actinide separation in the second cycle, the DIAMEX-SANEX process was adjusted to separate neptunium and plutonium along with americium and curium. The data showed the possibility to extract all actinides together with good selectivities versus lanthanides. The flowsheets of the two GANEX cycles which will be tested on a high active feed at the end of 2008 in Atalante facility are presented. (authors)

  17. Tritium Sequestration in Gen IV NGNP Gas Stream via Proton Conducting Ceramic Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fanglin Frank [Univ. of South Carolina, Columbia, SC (United States); Adams, Thad M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brinkman, Kyle [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Reifsnider, Kenneth [Univ. of South Carolina, Columbia, SC (United States)

    2011-09-30

    Several types of high-temperature proton conductors based on SrCeO3 and BaCeO3 have been systematically investigated in this project for tritium separation in NGNP applications. One obstacle for the field application is the chemical stability issues in the presence of steam and CO2 for these proton conductors. Several strategies to overcome such issues have been evaluated, including A site doping and B site co-doping method for perovskite-structured proton conductors. Novel zirconium-free proton conductors have also been developed with improved electrical conductivity and enhanced chemical stability. Novel catalytic materials for the proton-conducting separation membranes have been investigated. A tubular geometry proton-conducting membrane has been developed for the proton separation membranes. Total dose rate estimated from tritium decay (beta emission) under realistic membrane operating conditions, combined with electron irradiation experiments, indicates that proton ceramic materials possess the appropriate radiation stability for this application.

  18. GEN-IV BENCHMARKING OF TRISO FUEL PERFORMANCE MODELS UNDER ACCIDENT CONDITIONS MODELING INPUT DATA

    Energy Technology Data Exchange (ETDEWEB)

    Collin, Blaise Paul [Idaho National Laboratory

    2016-09-01

    This document presents the benchmark plan for the calculation of particle fuel performance on safety testing experiments that are representative of operational accidental transients. The benchmark is dedicated to the modeling of fission product release under accident conditions by fuel performance codes from around the world, and the subsequent comparison to post-irradiation experiment (PIE) data from the modeled heating tests. The accident condition benchmark is divided into three parts: • The modeling of a simplified benchmark problem to assess potential numerical calculation issues at low fission product release. • The modeling of the AGR-1 and HFR-EU1bis safety testing experiments. • The comparison of the AGR-1 and HFR-EU1bis modeling results with PIE data. The simplified benchmark case, thereafter named NCC (Numerical Calculation Case), is derived from “Case 5” of the International Atomic Energy Agency (IAEA) Coordinated Research Program (CRP) on coated particle fuel technology [IAEA 2012]. It is included so participants can evaluate their codes at low fission product release. “Case 5” of the IAEA CRP-6 showed large code-to-code discrepancies in the release of fission products, which were attributed to “effects of the numerical calculation method rather than the physical model” [IAEA 2012]. The NCC is therefore intended to check if these numerical effects subsist. The first two steps imply the involvement of the benchmark participants with a modeling effort following the guidelines and recommendations provided by this document. The third step involves the collection of the modeling results by Idaho National Laboratory (INL) and the comparison of these results with the available PIE data. The objective of this document is to provide all necessary input data to model the benchmark cases, and to give some methodology guidelines and recommendations in order to make all results suitable for comparison with each other. The participants should read this document thoroughly to make sure all the data needed for their calculations is provided in the document. Missing data will be added to a revision of the document if necessary. 09/2016: Tables 6 and 8 updated. AGR-2 input data added

  19. Consistent Multigroup Theory Enabling Accurate Course-Group Simulation of Gen IV Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rahnema, Farzad; Haghighat, Alireza; Ougouag, Abderrafi

    2013-11-29

    The objective of this proposal is the development of a consistent multi-group theory that accurately accounts for the energy-angle coupling associated with collapsed-group cross sections. This will allow for coarse-group transport and diffusion theory calculations that exhibit continuous energy accuracy and implicitly treat cross- section resonances. This is of particular importance when considering the highly heterogeneous and optically thin reactor designs within the Next Generation Nuclear Plant (NGNP) framework. In such reactors, ignoring the influence of anisotropy in the angular flux on the collapsed cross section, especially at the interface between core and reflector near which control rods are located, results in inaccurate estimates of the rod worth, a serious safety concern. The scope of this project will include the development and verification of a new multi-group theory enabling high-fidelity transport and diffusion calculations in coarse groups, as well as a methodology for the implementation of this method in existing codes. This will allow for a higher accuracy solution of reactor problems while using fewer groups and will reduce the computational expense. The proposed research represents a fundamental advancement in the understanding and improvement of multi- group theory for reactor analysis.

  20. Critical Success Factors for Lean Thinking in the Application of Industrialised Building System (IBS)

    Science.gov (United States)

    Yunus, Riduan; Noor, Siti Rahimah Mohd; Halid Abdullah, Abd; Nagapan, Sasitharan; Hamid, Abdul Rahim Abdul; Tajudin, Saiful Azhar Ahmad; Rohani Mat Jusof, Siti

    2017-08-01

    Productivity in the manufacturing process of building components can be increased by optimising each advantage that is available in each activity. Identification of critical success factors (CSFs) for lean thinking in the Industrialised Building System (IBS) will be able to minimise cost and reduce time needed to complete a project. The focus of lean thinking in construction is on the production process and the client’s requirement. In developing countries such as Malaysia, the integration of lean thinking in IBS applications is still low and there is a shortage of comprehensive strategies to integrate lean thinking. As key stakeholders, feedback from contractors, manufacturers, developers and the local authority will be able to help the identification of CSFs in integrating lean thinking in IBS applications. The data was collected through a questionnaire survey and analysed quantitatively. There are 31 CSFs for lean thinking in IBS which have been identified in this study. A conceptual model was developed to assist researchers in investigating the influences of CSFs for lean thinking in IBS applications. This study will assist construction players to improvise their manufacturing process in the implementation of IBS to eliminate unnecessary activities and focus instead on significant processes without generating physical and non-physical waste.

  1. Criticality and Excitation Gap in Quantum Systems: Applications of Continuous Matrix Product States in Imaginary Time

    CERN Document Server

    Tirrito, Emanuele; Ran, Shi-Ju

    2016-01-01

    We demonstrate an efficient method that allows for simultaneous determination of the ground state, low energy excitation properties and excitation gap in quantum many body systems. To this aim we first use the \\textit{ab-initio} optimization principle of tensor networks (TN), to show that the infinite density matrix renormalization group (iDMRG) in the real space is associated in a natural manner to the infinite time-evolving block decimation (iTEBD) implemented on a continuous matrix product state (MPS), and defined in imaginary time. We illustrate this association showing that the (imaginary) time matrix product state (MPS) in iTEBD reproduces accurately the properties of the two-dimensional (2D) classical Ising model, verifying in this way that the time MPS corresponds to a well-defined physical state. We apply then our scheme to the one-dimensional (1D) quantum Ising chain, where the time MPS is defined in continuous imaginary time. It is found that the time MPS at or close to the critical point is always...

  2. Cultural warrant as a justification in knowledge organization systems: A critical approach

    Directory of Open Access Journals (Sweden)

    Mario G. Barité

    2011-10-01

    Full Text Available An exploratory analysis of the "cultural warrant" concept is made with the objective of determining related future research areas. First, the generic notion of "warrant" is reviewed as it has been considered by Knowledge Organization. Different kinds of warrants proposed to legitimate the inclusion of terminology in knowledge organization systems are described. A critical analysis of the "culture" concept is carried out as well as the way in which the various anthropological, sociological and political point of views come together in its epistemological construction. The treatment of the cultural warrant in the relevant literature is reviewed and discussed. Its contribution to the construction of cultural identities through differentiation elements in the interpretation and life experience is valued.The relationship between cultural warrant and local culture is developed in-depth. The insertion of the ethical factor through of the cultural warrant is weighted in the development of classification schemes as well as the classification and indexing processes. The need to explore in greater detail the methodological alternatives which can be based upon this integrative and democratizing conception in the Knowledge Organization field is established among other conclusions

  3. Critical Factors Influencing Decision to Adopt Human Resource Information System (HRIS) in Hospitals.

    Science.gov (United States)

    Alam, Md Golam Rabiul; Masum, Abdul Kadar Muhammad; Beh, Loo-See; Hong, Choong Seon

    2016-01-01

    The aim of this research is to explore factors influencing the management decisions to adopt human resource information system (HRIS) in the hospital industry of Bangladesh-an emerging developing country. To understand this issue, this paper integrates two prominent adoption theories-Human-Organization-Technology fit (HOT-fit) model and Technology-Organization-Environment (TOE) framework. Thirteen factors under four dimensions were investigated to explore their influence on HRIS adoption decisions in hospitals. Employing non-probability sampling method, a total of 550 copies of structured questionnaires were distributed among HR executives of 92 private hospitals in Bangladesh. Among the respondents, usable questionnaires were 383 that suggesting a valid response rate of 69.63%. We classify the sample into 3 core groups based on the HRIS initial implementation, namely adopters, prospectors, and laggards. The obtained results specify 5 most critical factors i.e. IT infrastructure, top management support, IT capabilities of staff, perceived cost, and competitive pressure. Moreover, the most significant dimension is technological dimension followed by organisational, human, and environmental among the proposed 4 dimensions. Lastly, the study found existence of significant differences in all factors across different adopting groups. The study results also expose constructive proposals to researchers, hospitals, and the government to enhance the likelihood of adopting HRIS. The present study has important implications in understanding HRIS implementation in developing countries.

  4. Water Quality Improvement Performance of Geotextiles Within Permeable Pavement Systems: A Critical Review

    Directory of Open Access Journals (Sweden)

    Miklas Scholz

    2013-04-01

    Full Text Available Sustainable drainage systems (SuDS; or best management practices are increasingly being used as ecological engineering techniques to prevent the contamination of receiving watercourses and groundwater. Permeable paving is a SuDS technique, which is commonplace in car parks, driveways and minor roads where one of their functions is to improve the quality of urban runoff. However, little is known about the water quality benefits of incorporating an upper geotextile within the paving structure. The review focuses on five different categories of pollutants: organic matter, nutrients, heavy metals, motor oils, suspended solids originating from street dust, and chloride. The paper critically assesses results from previous international tests and draws conclusions on the scientific rigour and significance of the data. Findings indicate that only very few studies have been undertaken to address the role of geotextiles directly. All indications are that the presence of a geotextile leads only to minor water quality improvements. For example, suspended solids are being held back by the geotextile and these solids sometimes contain organic matter, nutrients and heavy metals. However, most studies were inconclusive and data were often unsuitable for further statistical analysis. Further long-term research on industry-relevant, and statistically and scientifically sound, experimental set-ups is recommended.

  5. Development of a rotor alloy for advanced ultra super critical turbine power generation system

    Energy Technology Data Exchange (ETDEWEB)

    Miyashita, Shigekazu; Yamada, Masayuki; Suga, Takeo; Imai, Kiyoshi; Nemoto, Kuniyoshi; Yoshioka, Youmei [Toshiba Corporation, Yokohama (Japan)

    2008-07-01

    A Ni-based superalloy ''TOS1X'', for the rotor material of the 700 class advanced ultra super critical (A-USC) turbine power generation system was developed. TOS1X is an alloy that is improved in the creep rupture strength of Inconel trademark 617 maintaining both forgeability and weldability. The 7 t weight model rotor made of TOS1X was manufactured by double melt process, vacuum induction melting and electro slag remelting, and forging. During forging process, forging cracks and any other abnormalities were not detected on the ingots. The metallurgical and the mechanical properties in this rotor were investigated. Macro and micro structure observation, and some mechanical tests were conducted. According to the metallurgical structure investigation, there was no remarkable segregation in whole area and the forging effect was reached in the center part of the rotor ingot. The results of tensile test and creep rupture test proved that proof stress and tensile stress of the TOS1X are higher than those of Inconel trademark 617 and creep rupture strength of TOS1X is much superior than that of Inconel trademark 617. (orig.)

  6. Critical factors of implementing Industrialised Building System in Sarawak: A research on SMEs

    Science.gov (United States)

    Hadi, N. A.; Muhamad, W. M. N. W.; Othman, M. K. F.

    2017-05-01

    Industrialised Building System (IBS) have been adopted in Malaysia for over five decades and is expected to grow consistent with Malaysia's economic development. In promoting the adoption of IBS in construction projects, the government has taken several steps such as levy exemption for contractors and developers. Despite its numerous advantages and efforts pulled by the government, the implementation and adoption of IBS are still below the expected figure. Many researchers investigated readiness, setbacks and issues related to the implementation of IBS in Malaysia's construction projects. However, most of the research mainly for projects located in urban areas of West Malaysia. Therefore, this paper aims to close the gap on factors affecting the implementation of IBS for SMEs in Sarawak, where the level urbanisation is low. A semi-structured interview was conducted with 10 SME's contractors to get better insight view. The study found that logistics and infrastructure problems, a limited number of the manufacturer, lack of incentive, conventional payment methods, lack of financial supports are among critical factors affecting the implementation of IBS. Therefore, it was concluded that government plays major role in providing supports, incentives and facilitating the improvement of infrastructure to successfully implementing IBS in Sarawak.

  7. A system for improving fall detection performance using critical phase fall signal and a neural network

    Directory of Open Access Journals (Sweden)

    Patimakorn Jantaraprim

    2012-12-01

    Full Text Available We present a system for improving fall detection performance using a short time min-max feature based on the specificsignatures of critical phase fall signal and a neural network as a classifier. Two subject groups were tested: Group A involvingfalls and activities by young subjects; Group B testing falls by young and activities by elderly subjects. The performance wasevaluated by comparing the short time min-max with a maximum peak feature using a feed-forward backpropagation networkwith two-fold cross validation. The results, obtained from 672 sequences, show that the proposed method offers a betterperformance for both subject groups. Group B’s performance is higher than Group A’s. The best performances are 98.2%sensitivity and 99.3% specificity for Group A, and 99.4% sensitivity and 100% specificity for Group B. The proposed systemuses one sensor for a body’s position, without a fixed threshold for 100% sensitivity or specificity and without additionalprocessing of posture after a fall.

  8. What do we mean by Human-Centered Design of Life-Critical Systems?

    Science.gov (United States)

    Boy, Guy A

    2012-01-01

    Human-centered design is not a new approach to design. Aerospace is a good example of a life-critical systems domain where participatory design was fully integrated, involving experimental test pilots and design engineers as well as many other actors of the aerospace engineering community. This paper provides six topics that are currently part of the requirements of the Ph.D. Program in Human-Centered Design of the Florida Institute of Technology (FIT.) This Human-Centered Design program offers principles, methods and tools that support human-centered sustainable products such as mission or process control environments, cockpits and hospital operating rooms. It supports education and training of design thinkers who are natural leaders, and understand complex relationships among technology, organizations and people. We all need to understand what we want to do with technology, how we should organize ourselves to a better life and finally find out whom we are and have become. Human-centered design is being developed for all these reasons and issues.

  9. 75 FR 81264 - Critical Path Transmission, LLC; Clear Power, LLC; v. California Independent System Operator, Inc...

    Science.gov (United States)

    2010-12-27

    ... Energy Regulatory Commission Critical Path Transmission, LLC; Clear Power, LLC; v. California Independent... (Commission), 18 CFR 385.206 (2010) and sections 206 and 306 of the Federal Power Act, 16 U.S.C. 824e and 825e (2006), Critical Path Transmission, LLC and Clear Power LLC (Complainants) filed a complaint...

  10. Critical behavior of isotropic three-dimensional systems with dipole-dipole interactions

    Energy Technology Data Exchange (ETDEWEB)

    Belim, S. M., E-mail: sbelim@mail.ru [Dostoevsky Omsk State University (Russian Federation)

    2013-06-15

    The critical behavior of Heisenberg magnets with dipole-dipole interactions near the line of second-order phase transitions directly in three-dimensional space is investigated in terms of a field-theoretic approach. The dependences of critical exponents on the dipole-dipole interaction parameter are derived. Comparison with experimental facts is made.

  11. Developing a Critical Lens among Preservice Teachers while Working within Mandated Performance-Based Assessment Systems

    Science.gov (United States)

    Moss, Glenda

    2008-01-01

    This article addresses the dilemma of promoting critical pedagogy within portfolio assessment, which has been implemented in many teacher education programs to meet state and national mandates for performance-based assessment. It explores how one teacher educator works to move portfolio assessment to a level of critical self-reflection that…

  12. On the critical periods of Liénard systems with cubic restoring forces

    Directory of Open Access Journals (Sweden)

    Zhengdong Du

    2004-01-01

    show that for a weak center of type I, at most [(1/2deg(F(x]−1 local critical periods can bifurcate and the maximum number can be reached. For a weak center of type II, the maximum number of local critical periods that can bifurcate is at least [(1/4deg(F(x].

  13. The implementation of a Hazard Analysis and Critical Control Point management system in a peanut butter ice cream plant

    Directory of Open Access Journals (Sweden)

    Yu-Ting Hung

    2015-09-01

    Full Text Available To ensure the safety of the peanut butter ice cream manufacture, a Hazard Analysis and Critical Control Point (HACCP plan has been designed and applied to the production process. Potential biological, chemical, and physical hazards in each manufacturing procedure were identified. Critical control points for the peanut butter ice cream were then determined as the pasteurization and freezing process. The establishment of a monitoring system, corrective actions, verification procedures, and documentation and record keeping were followed to complete the HACCP program. The results of this study indicate that implementing the HACCP system in food industries can effectively enhance food safety and quality while improving the production management.

  14. Nonlinear Stochastic Dynamics of Complex Systems, II: Potential of Entropic Force in Markov Systems with Nonequilibrium Steady State, Generalized Gibbs Function and Criticality

    CERN Document Server

    Thompson, Lowell F

    2016-01-01

    In this paper we revisit the notion of the "minus logarithm of stationary probability" as a generalized potential in nonequilibrium systems and attempt to illustrate its central role in an axiomatic approach to stochastic nonequilibrium thermodynamics of complex systems. It is demonstrated that this quantity arises naturally through both monotonicity results of Markov processes and as the rate function when a stochastic process approaches a detrministic limit. We then undertake a more detailed mathematical analysis of the consequences of this quantity, culminating in a necessary and sufficient condition for the criticality of stochastic systems. This condition is then discussed in the context of recent results about criticality in biological systems.

  15. Success and failure of biological treatment in systemic lupus erythematosus: A critical analysis.

    Science.gov (United States)

    Gatto, Mariele; Saccon, Francesca; Zen, Margherita; Bettio, Silvano; Iaccarino, Luca; Punzi, Leonardo; Doria, Andrea

    2016-11-01

    Patients affected with systemic lupus erythematosus (SLE) still display increased mortality and decreased quality of life in respect to general population. The major determinant of poor long term prognosis is organ damage, which is predictive of more damage and death. Damage is in turn triggered by uncontrolled disease activity and especially by the long-standing corticosteroid use which often accompanies SLE patients over their disease course, owing both to the need of reaching disease remission and to the habit of keeping patients on a small steroid dose for an indefinite period of time. Hence, the need for new drugs and therapeutic strategies aiming at minimizing damage accrual through a better control of disease activity and a steroid-sparing potential is paramount. So far, however, the therapeutic strategy in SLE requires a multitarget approach which is not devoid of widespread immunesuppression. In fact, several studies have been carried out in recent years targeting both the adaptive and the innate immune system, the majority of which did not achieve their primary endpoint, being often divergent from successful clinical experience and thereby committing physician to off-label use of targeted therapies in face of refractory SLE manifestations. The study designs and the chosen endpoints were often blamed for inadequacy, being at least in part responsible for study failures. In this review, we go over major clinical trials conducted in SLE by analyzing any critical aspects related to study design, predefined endpoints and biological activity of novel compounds that may have hampered study outcome, despite the great effort of providing less toxic drugs within a targeted, pathogenic-based approach.

  16. Task Migration for Fault-Tolerance in Mixed-Criticality Embedded Systems

    DEFF Research Database (Denmark)

    Saraswat, Prabhat Kumar; Pop, Paul; Madsen, Jan

    2009-01-01

    In this paper we are interested in mixed-criticality embedded applications implemented on distributed architectures. Depending on their time-criticality, tasks can be hard or soft real-time and regarding safety-criticality, tasks can be fault-tolerant to transient faults, permanent faults, or have...... no dependability requirements. We use Earliest Deadline First (EDF) scheduling for the hard tasks and the Constant Bandwidth Server (CBS) for the soft tasks. The CBS parameters determine the quality of service (QoS) of soft tasks. Transient faults are tolerated using checkpointing with roll- back recovery....... For tolerating permanent faults in processors, we use task migration, i.e., restarting the safety-critical tasks on other processors. We propose a Greedy-based on- line heuristic for the migration of safety-critical tasks, in response to permanent faults, and the adjustment of CBS parameters on the target...

  17. Dependence on molecular parameters of the heat capacity critical behaviour for nitroalkane + alcohol binary systems

    Science.gov (United States)

    Souto-Caride, M.; Troncoso, J.; Losada-Pérez, P.; Peleteiro, J.; Carballo, E.; Romani, L.

    2009-04-01

    Heat capacities per unit volume for a set of nitroalkane + alcohol critical mixtures near their upper consolute point are presented. The selected nitroalkanes were nitromethane and nitroethane whereas the 1-alcohol series from 1-propanol to 1-decanol was studied. The critical anomaly of nitroalkane + non-primary alcohols was also investigated; 2-propanol, 2-pentanol, 3-pentanol and 5-nonanol were chosen to this end. The heat capacity data are obtained at atmospheric pressure as a function of temperature in the homogeneous and heterogeneous regions by means of a differential scanning calorimeter. The exponent and amplitudes that characterises the observed critical anomaly are determined from experimental data, being their values coherent with previous results. In addition, the critical amplitude of the correlation length was calculated using the universality of the two-scale factor. Finally, the changes in the critical parameters as a function of the molecular structure of both nitroalkane and alcohol are analysed.

  18. The Art of Displacement: Designing Experiential Systems and Transverse Epistemologies as Conceptual Criticism

    Directory of Open Access Journals (Sweden)

    Rolf Hughes

    2014-07-01

    Full Text Available With architects and designers increasingly facing problems that are neither predictable nor simple but highly complex, a particular synthesis of design intelligence and creativity is required. If the art of being a professional is becoming ‘the art of managing complexity’, what are the ‘boundaries’ of professional practice? ‘Trans-disciplinarity’, for example, requires liminal or neither/nor thinking (thus ‘boundary concepts’ remain a core concern. A concern with boundaries and ‘edges’ implies in turn a concern with ‘relationality’ (i.e. how we establish relations, positions, borders between different disciplinary priorities and methods and thence a problem that affects how we think of disciplinarity, interdisciplinarity, networks of various kinds, and trans-disciplinarity – that of ‘substance’, ‘content’ or ‘matter’.This paper subjects design research, theory and practice to transverse epistemologies, attempting a ‘flow of transformations’ via such themes as authorship, remediation, smuggling, disruptive innovation, performative knowledge, and gesture versus identity. It brings together an ars combinatoria of conceptual criticism, trans-disciplinary practice as ‘disruptive innovation’, Michael Speaks’s notion of ‘design intelligence’ and Margaret Boden’s three types of creativity – combinatorial, exploratory, and transformational – seeking thereby to suggest new structures that might yield ‘transdisciplines’. Departing from two separate points – Bruno Latour’s call for ‘earthly accounts of buildings and design processes’ and Jack Burnham’s identification of a paradigm shift from an ‘object-oriented’ to a ‘systems-oriented’ culture – the paper describes the formation of a new interdisciplinary practice, experience design (the design of meaningful experience across time, as a form of ‘epistemological Conceptualism’. This prioritises critical thinking and

  19. Comparison of KENO-VI and MCNP5 Criticality Analyses for a Lunar Regolith Clustered-Reactor System

    Science.gov (United States)

    Bess, John Darrell

    2008-01-01

    The Lunar Regolith Clustered-Reactor System design has been presented as an alternative method for providing surface power to a lunar facility using a fast-fission, heatpipe-cooled nuclear reactor. The reactor system is divided into subcritical units that can be safely launched into orbit without risk of inadvertent criticality in the event of a launch accident. The reactor subunits are emplaced into the lunar surface to form a clustered-reactor system, utilizing the regolith as both radiation shielding and neutron-reflector material. Coordinated placement of multiple subunits can provision a critical reactor system proportional to localized lunar surface power demand. Reactor units assembled using proven and tested materials in radiation environments such as UO2 fuel, stainless-steel cladding and support, and compatible liquid-metal heatpipes promote safety and reliability, with ease of manufacture and testing. Reactor power levels of approximately 100 kWth per subunit significantly reduces the negative effects of elevated temperature and radiation environments associated with single nuclear power reactors operated at higher power levels. The analysis of subunit criticality in various accident scenarios differs by up to 4% (~$6 in reactivity) between results generated using conventional criticality analysis codes, MCNP5 and KENO-VI. A demonstrated trend exists between results of the two criticality codes as accident conditions approach a multiplication factor of one. Code comparison of a tri-cluster system on the lunar surface provides comparable results with calculated system reactivity within 0.5%. Iron concentration is confirmed as the dominant element in the lunar regolith influencing system reactivity.

  20. Cyber-Physical Systems for Critical Infrastructure Protection: A Wireless Sensor Network Application for Electric Grid Monitoring

    Science.gov (United States)

    Saint, Martin

    Critical infrastructure includes resources which are essential to the function of society. Despite an increased focus on protecting U.S. critical infrastructure, some sectors including the electric grid are more vulnerable than ever. Existing critical infrastructure protection (CIP) regulations and the monitoring and control systems used to achieve them have not met performance expectations. This indicates that the next generation of grid control should explore new architectures. This thesis explores the question of whether a cyber-physical system in the form of wireless sensor networks can be used to improve CIP. We examine efforts by others to design a wireless sensor module for monitoring transmission and distribution lines, and note that this work includes little information about the performance of the communications subsystem. Laboratory testing of throughput and reliability for one example communication network are undertaken here, along with consideration of the short message service as one alternative for backhauling sensor data.