An Augmented Fast Marching Method for Computing Skeletons and Centerlines
Telea, Alexandru; Wijk, Jarke J. van
2002-01-01
We present a simple and robust method for computing skeletons for arbitrary planar objects and centerlines for 3D objects. We augment the Fast Marching Method (FMM) widely used in level set applications by computing the paramterized boundary location every pixel came from during the boundary
Feature extraction from mammographic images using fast marching methods
International Nuclear Information System (INIS)
Bottigli, U.; Golosio, B.
2002-01-01
Features extraction from medical images represents a fundamental step for shape recognition and diagnostic support. The present work faces the problem of the detection of large features, such as massive lesions and organ contours, from mammographic images. The regions of interest are often characterized by an average grayness intensity that is different from the surrounding. In most cases, however, the desired features cannot be extracted by simple gray level thresholding, because of image noise and non-uniform density of the surrounding tissue. In this work, edge detection is achieved through the fast marching method (Level Set Methods and Fast Marching Methods, Cambridge University Press, Cambridge, 1999), which is based on the theory of interface evolution. Starting from a seed point in the shape of interest, a front is generated which evolves according to an appropriate speed function. Such function is expressed in terms of geometric properties of the evolving interface and of image properties, and should become zero when the front reaches the desired boundary. Some examples of application of such method to mammographic images from the CALMA database (Nucl. Instr. and Meth. A 460 (2001) 107) are presented here and discussed
A highly scalable massively parallel fast marching method for the Eikonal equation
Yang, Jianming; Stern, Frederick
2017-03-01
The fast marching method is a widely used numerical method for solving the Eikonal equation arising from a variety of scientific and engineering fields. It is long deemed inherently sequential and an efficient parallel algorithm applicable to large-scale practical applications is not available in the literature. In this study, we present a highly scalable massively parallel implementation of the fast marching method using a domain decomposition approach. Central to this algorithm is a novel restarted narrow band approach that coordinates the frequency of communications and the amount of computations extra to a sequential run for achieving an unprecedented parallel performance. Within each restart, the narrow band fast marching method is executed; simple synchronous local exchanges and global reductions are adopted for communicating updated data in the overlapping regions between neighboring subdomains and getting the latest front status, respectively. The independence of front characteristics is exploited through special data structures and augmented status tags to extract the masked parallelism within the fast marching method. The efficiency, flexibility, and applicability of the parallel algorithm are demonstrated through several examples. These problems are extensively tested on six grids with up to 1 billion points using different numbers of processes ranging from 1 to 65536. Remarkable parallel speedups are achieved using tens of thousands of processes. Detailed pseudo-codes for both the sequential and parallel algorithms are provided to illustrate the simplicity of the parallel implementation and its similarity to the sequential narrow band fast marching algorithm.
On the implementation of fast marching methods for 3D lattices
DEFF Research Database (Denmark)
Bærentzen, Jakob Andreas
2001-01-01
This technical report discusses Sethian's Fast Marching Method and its higher accuracy variant. Both methods may be used to compute the arrival times at the points of a discrete lattice of a front which is monotonously expanding. Applications of the method include arrival time computation and the...
Schwenke, M; Hennemuth, A; Fischer, B; Friman, O
2012-01-01
Phase-contrast MRI (PC MRI) can be used to assess blood flow dynamics noninvasively inside the human body. The acquired images can be reconstructed into flow vector fields. Traditionally, streamlines can be computed based on the vector fields to visualize flow patterns and particle trajectories. The traditional methods may give a false impression of precision, as they do not consider the measurement uncertainty in the PC MRI images. In our prior work, we incorporated the uncertainty of the measurement into the computation of particle trajectories. As a major part of the contribution, a novel numerical scheme for solving the anisotropic Fast Marching problem is presented. A computing time comparison to state-of-the-art methods is conducted on artificial tensor fields. A visual comparison of healthy to pathological blood flow patterns is given. The comparison shows that the novel anisotropic Fast Marching solver outperforms previous schemes in terms of computing time. The visual comparison of flow patterns directly visualizes large deviations of pathological flow from healthy flow. The novel anisotropic Fast Marching solver efficiently resolves even strongly anisotropic path costs. The visualization method enables the user to assess the uncertainty of particle trajectories derived from PC MRI images.
International Nuclear Information System (INIS)
Losnegaard, Are; Hodneland, Erlend; Lundervold, Arvid; Hysing, Liv Bolstad; Muren, Ludvig Paul
2010-01-01
A fast and accurate segmentation of organs at risk, such as the healthy colon, would be of benefit for planning of radiotherapy, in particular in an adaptive scenario. For the treatment of pelvic tumours, a great challenge is the segmentation of the most adjacent and sensitive parts of the gastrointestinal tract, the sigmoid and descending colon. We propose a semi-automated method to segment these bowel parts using the fast marching (FM) method. Standard 3D computed tomography (CT) image data obtained from routine radiotherapy planning were used. Our pre-processing steps distinguish the intestine, muscles and air from connective tissue. The core part of our method separates the sigmoid and descending colon from the muscles and other segments of the intestine. This is done by utilizing the ability of the FM method to compute a specified minimal energy functional integrated along a path, and thereby extracting the colon centre line between user-defined control points in the sigmoid and descending colon. Further, we reconstruct the tube-shaped geometry of the sigmoid and descending colon by fitting ellipsoids to points on the path and by adding adjacent voxels that are likely voxels belonging to these bowel parts. Our results were compared to manually outlined sigmoid and descending colon, and evaluated using the Dice coefficient (DC). Tests on 11 patients gave an average DC of 0.83 (±0.07) with little user interaction. We conclude that the proposed method makes it possible to fast and accurately segment the sigmoid and descending colon from routine CT image data.
Wilde-Piorko, M.; Polkowski, M.
2016-12-01
Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation final release of a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. Source code of pySeismicFMM will be published before Fall Meeting. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.
Review of Fast Reactor Activities, March 1980
International Nuclear Information System (INIS)
Balz, W.
1980-01-01
As in previous years, a short outline of the major achievements made since the last IWGFR meeting is given in the following. On 18 February 1980 the Council of Ministers has approved a resolution in which they recognise the strategic importance of fast breeder reactors and the need to continue the efforts towards maintaining an effective fast breeder option in the Member States
A fast marching algorithm for the factored eikonal equation
Energy Technology Data Exchange (ETDEWEB)
Treister, Eran, E-mail: erantreister@gmail.com [Department of Earth and Ocean Sciences, The University of British Columbia, Vancouver, BC (Canada); Haber, Eldad, E-mail: haber@math.ubc.ca [Department of Earth and Ocean Sciences, The University of British Columbia, Vancouver, BC (Canada); Department of Mathematics, The University of British Columbia, Vancouver, BC (Canada)
2016-11-01
The eikonal equation is instrumental in many applications in several fields ranging from computer vision to geoscience. This equation can be efficiently solved using the iterative Fast Sweeping (FS) methods and the direct Fast Marching (FM) methods. However, when used for a point source, the original eikonal equation is known to yield inaccurate numerical solutions, because of a singularity at the source. In this case, the factored eikonal equation is often preferred, and is known to yield a more accurate numerical solution. One application that requires the solution of the eikonal equation for point sources is travel time tomography. This inverse problem may be formulated using the eikonal equation as a forward problem. While this problem has been solved using FS in the past, the more recent choice for applying it involves FM methods because of the efficiency in which sensitivities can be obtained using them. However, while several FS methods are available for solving the factored equation, the FM method is available only for the original eikonal equation. In this paper we develop a Fast Marching algorithm for the factored eikonal equation, using both first and second order finite-difference schemes. Our algorithm follows the same lines as the original FM algorithm and requires the same computational effort. In addition, we show how to obtain sensitivities using this FM method and apply travel time tomography, formulated as an inverse factored eikonal equation. Numerical results in two and three dimensions show that our algorithm solves the factored eikonal equation efficiently, and demonstrate the achieved accuracy for computing the travel time. We also demonstrate a recovery of a 2D and 3D heterogeneous medium by travel time tomography using the eikonal equation for forward modeling and inversion by Gauss–Newton.
Two-dimensional fast marching for geometrical optics.
Capozzoli, Amedeo; Curcio, Claudio; Liseno, Angelo; Savarese, Salvatore
2014-11-03
We develop an approach for the fast and accurate determination of geometrical optics solutions to Maxwell's equations in inhomogeneous 2D media and for TM polarized electric fields. The eikonal equation is solved by the fast marching method. Particular attention is paid to consistently discretizing the scatterers' boundaries and matching the discretization to that of the computational domain. The ray tracing is performed, in a direct and inverse way, by using a technique introduced in computer graphics for the fast and accurate generation of textured images from vector fields. The transport equation is solved by resorting only to its integral form, the transport of polarization being trivial for the considered geometry and polarization. Numerical results for the plane wave scattering of two perfectly conducting circular cylinders and for a Luneburg lens prove the accuracy of the algorithm. In particular, it is shown how the approach is capable of properly accounting for the multiple scattering occurring between the two metallic cylinders and how inverse ray tracing should be preferred to direct ray tracing in the case of the Luneburg lens.
3D pulmonary nodules detection using fast marching segmentation ...
African Journals Online (AJOL)
This paper proposes an automated computer aided diagnosis system for detection of pulmonary nodules based on three dimensional (3D) structures. Lung ... The proposed detection methodology can give the accuracy of 92%. Keywords: lung cancer; pulmonary nodule; fast marching; 3D features; random forest classifier.
Review of the United Kingdom fast reactor programme - March 1986
International Nuclear Information System (INIS)
Bramman, J.I.; John, C.T.; Wheeler, R.C.
1986-01-01
The UK programme in the field of fast reactors has continued successfully towards the following main objectives, details of which are contained in subsequent sections of this report: (2) progress with the prototype fast reactor (PFR) which achieved its design power on 4 March 1985; (3) nuclear fuel reprocessing; (4) commercial design studies; (5) structural integrity of LMFBR during its lifetime; (6) R and D work on components of LMFBR; (7) materials study; (8) sodium chemistry; (9) reactor core and fuel design philosophy; (10) safety problems; (11) plant performance studies
Status of the DEBENE fast breeder reactor development, March 1979
International Nuclear Information System (INIS)
Daeunert, U.; Kessler, G.
1979-01-01
Status report of the Fast-breeder reactor development in Germany covers the following: description of the political situation in Federal republic of germany during 1978; international cooperation in the field of fast reactor technology development; operation description of the KNK-II fast core experimental power plant; status of construction of the SNR-300; results of the research and development programs concerned with fuel element, cladding, absorber rods and core structural materials development; sodium effects; neutron irradiation effects on SS properties; reactor physics related to experiments in fast critical assemblies; fast reactor safety issues; core disruption accidents; sodium boiling experiments, measuring methods developed; component tests
Status of the DEBENE fast breeder reactor development, March 1979
Energy Technology Data Exchange (ETDEWEB)
Daeunert, U; Kessler, G
1979-07-01
Status report of the Fast-breeder reactor development in Germany covers the following: description of the political situation in Federal republic of germany during 1978; international cooperation in the field of fast reactor technology development; operation description of the KNK-II fast core experimental power plant; status of construction of the SNR-300; results of the research and development programs concerned with fuel element, cladding, absorber rods and core structural materials development; sodium effects; neutron irradiation effects on SS properties; reactor physics related to experiments in fast critical assemblies; fast reactor safety issues; core disruption accidents; sodium boiling experiments, measuring methods developed; component tests.
Video Segmentation Using Fast Marching and Region Growing Algorithms
Directory of Open Access Journals (Sweden)
Eftychis Sifakis
2002-04-01
Full Text Available The algorithm presented in this paper is comprised of three main stages: (1 classification of the image sequence and, in the case of a moving camera, parametric motion estimation, (2 change detection having as reference a fixed frame, an appropriately selected frame or a displaced frame, and (3 object localization using local colour features. The image sequence classification is based on statistical tests on the frame difference. The change detection module uses a two-label fast marching algorithm. Finally, the object localization uses a region growing algorithm based on the colour similarity. Video object segmentation results are shown using the COST 211 data set.
A review of fast reactor progress in Japan, March 1979
Energy Technology Data Exchange (ETDEWEB)
Tomabechi, K
1979-07-01
The fast reactor development project in Japan will be continued in the next fiscal year, from April 1979 through March 1980, at a similar scale of effort both in budget and personnel, to those of the fiscal year of 1978. The total budget for LMFBR development for the next fiscal year is approximately 24 billion Yen, excluding wages of the personnel of the Power Reactor and Nuclear Fuel Development Corporation, PNC. The number of the technical people currently engaging in the fast reactor development in the PNC is approximately 500, excluding those working for plutonium fuel fabrication. Concerning the experimental fast reactor JOYO, approval for power increase from presently approved 50 MWt to 75 MWt with the present core and also to 100 MWt with a modified core in the future was granted by the regulatory authority in September 1978. Two operational cycles at 50 MWt have been completed very recently and preparation for power increase to 75 MWt is being made. With respect to the prototype fast breeder reactor MONJU, progress toward construction is being made and an environmental impact statement of MONJU filed last autumn is being reviewed by the concerned authorities. By the new atomic energy law recently made effective in Japan, the tasks of the former Japan Atomic Energy Commission were split into two and the Atomic Energy Safety Commission was newly established on 4th October 1978 in order to deal with nuclear safety problems in the country. All other problems are treated by the Atomic Energy Commission, as before. Highlights and topics of the fast reactor development activities in the past twelve months are summarized in this paper.
A Review of the UK Fast Reactor Programme: March 1980
International Nuclear Information System (INIS)
Smith, R.D.
1980-01-01
Towards the end of 1979 the Government announced a new programme of thermal reactor stations to be built over ten years (totalling 15GW), in addition to the two AGR stations at Torness and Heysham 'B' which had been approved by the previous Government. The first station of the new programme will be based on a Westinghouse PWR, subject to safety clearance and the outcome of a public inquiry, and it is envisaged that the remaining stations of the programme would be split between PWRs and AGRs. The AEA Chairman wrote formally to the Secretary of State for Energy in December 1979, putting forward on behalf of the Electricity Supply Authorities, NNC, BNFL and the AEA a recommended strategy for building the Commercial Demonstration Fast Reactor (CDFR), subject to normal licensing procedure and to public inquiry, so as to ensure that the key options for introducing commercial fast reactors, when required, should remain open. A Government statement is expected during the next few months. Meanwhile the level of effort on fast reactor research and development in the UK has been maintained, the fast reactor remaining the largest of the UKAEA's reactor development projects with expenditure totalling somewhat over £80M per annum. The main feature of the UK fast reactor programme has continued to be the operation of PFR (Sections 2 and 7) which is yielding a wealth of experience and of information relevant to the design of commercial fast reactors. Bum-up of standard driver fuel has reached 6-7% by heavy atoms, while specially enriched lead fuel pins have reached 11 % without failure. An extensive programme of work in the reactor and its associated steam plant was completed in March 1980 and the reactor then started its fifth power run. The fuel reprocessing plant at DNE is being commissioned and has reprocessed some of the spent fuel remaining from the DFR. It will start soon on reprocessing fuel discharged from the PFR. During the year improvements to the design of the future
A review of the UK fast reactor programme. March 1977
International Nuclear Information System (INIS)
Smith, R.D.
1977-01-01
This paper reports on the Fast Reactor Programme of United Kingdom. These are the main lines: Dounreay Fast Reactor; Prototype Fast Reactor; Commercial Fast Reactor; engineering development; materials development; chemical engineering/sodium technology; fast reactor fuel; fuel cycle; safety; reactor performance study
A review of the UK fast reactor programme, March 1981
International Nuclear Information System (INIS)
Smith, R.D.
1981-01-01
steam cycle, a re-evaluation of various boiler design styles have been undertaken. The types being studied cover straight tube, U and J tube, hockey stick and helical coil designs. A final choice of steam generator for CDFR has not yet been made. Key features in design selection are overall integrity to ensure high availability, ease of maintenance and repair following minor tube leaks, resistance to escalation of minor leaks to more major sodium/water reaction incidents. inspectability, relevance of previous experience and capital cost. Operation of the PFR was interrupted by a series of small leaks in the tube-to-tube plate welds in the three evaporator units. The key areas have now been shot-peened to remove tensile stresses in the surface material. the units have been repaired and operation at high power should be restarted during March 1981. The performance of the core and primary circuits has continued to be excellent. A major step forward was taken when the first 16 sub-assemblies were reprocessed in the PFR reprocessing plant. During the year a system economic study has been completed to assist in providing a sound technical basis for a fast reactor inquiry. This study was based on a set of programme assumptions and economic ground rules developed and agreed in 1978 within the UK nuclear industry and updated in 1979. Broadly, it was concluded that the introduction of the fast reactor as soon and as rapidly as feasible also leads, even on conservative uranium price assumptions. to economic benefits, the benefits being greatest when electrical demand and raw fuel prices are at their highest. The benefits are little affected by 25% increases in costs, except for an increase in fast reactor capital cost when uranium stays cheap; in this case the benefit virtually disappears if it is assumed that all other capital costs stay constant. Use of the fast reactor also produces a dramatic fall (almost three-fold) in the need uranium imports and, if market forces are
A review of the UK fast reactor programme, March 1981
Energy Technology Data Exchange (ETDEWEB)
Smith, R D [Risley Nuclear Power Development Establishment, Risley, Warrington (United Kingdom)
1981-05-01
steam cycle, a re-evaluation of various boiler design styles have been undertaken. The types being studied cover straight tube, U and J tube, hockey stick and helical coil designs. A final choice of steam generator for CDFR has not yet been made. Key features in design selection are overall integrity to ensure high availability, ease of maintenance and repair following minor tube leaks, resistance to escalation of minor leaks to more major sodium/water reaction incidents. inspectability, relevance of previous experience and capital cost. Operation of the PFR was interrupted by a series of small leaks in the tube-to-tube plate welds in the three evaporator units. The key areas have now been shot-peened to remove tensile stresses in the surface material. the units have been repaired and operation at high power should be restarted during March 1981. The performance of the core and primary circuits has continued to be excellent. A major step forward was taken when the first 16 sub-assemblies were reprocessed in the PFR reprocessing plant. During the year a system economic study has been completed to assist in providing a sound technical basis for a fast reactor inquiry. This study was based on a set of programme assumptions and economic ground rules developed and agreed in 1978 within the UK nuclear industry and updated in 1979. Broadly, it was concluded that the introduction of the fast reactor as soon and as rapidly as feasible also leads, even on conservative uranium price assumptions. to economic benefits, the benefits being greatest when electrical demand and raw fuel prices are at their highest. The benefits are little affected by 25% increases in costs, except for an increase in fast reactor capital cost when uranium stays cheap; in this case the benefit virtually disappears if it is assumed that all other capital costs stay constant. Use of the fast reactor also produces a dramatic fall (almost three-fold) in the need uranium imports and, if market forces are
A review of the UK fast reactor programme, March 1979
International Nuclear Information System (INIS)
Smith, R.D.
1979-01-01
The Status report of the UK activities related to fast-breeder reactor activities includes the following: summary of the operating experience of the prototype Fast Reactor (PFR) during 1978; design studies of the commercial demonstration fast reactor (CDFR); design studies of later advanced LMFBR; engineering developments of high temperature sodium loop, steam generators and instrumentation; materials development; corrosion problems; sodium technology; fuel elements development; PFR fuel reprocessing; safety issues molten fuel-coolant interaction; core structure test; accident analysis; reactor performance studies; experimental reactor physics; fuel management and general neutronics calculation for CDFR; reactor instruments
A review of the UK fast reactor programme, March 1979
Energy Technology Data Exchange (ETDEWEB)
Smith, R D
1979-07-01
The Status report of the UK activities related to fast-breeder reactor activities includes the following: summary of the operating experience of the prototype Fast Reactor (PFR) during 1978; design studies of the commercial demonstration fast reactor (CDFR); design studies of later advanced LMFBR; engineering developments of high temperature sodium loop, steam generators and instrumentation; materials development; corrosion problems; sodium technology; fuel elements development; PFR fuel reprocessing; safety issues molten fuel-coolant interaction; core structure test; accident analysis; reactor performance studies; experimental reactor physics; fuel management and general neutronics calculation for CDFR; reactor instruments.
A review of the United Kingdom fast reactor program - March 1983
International Nuclear Information System (INIS)
Smith, R.D.
1983-01-01
A review of the United Kingdom Fast Reactor Programme was given in March 1983. Operational experience with the Prototype Fast Reactor (PFR) is briefly summarized. The design concept of the Commercial Demonstration Fast Reactor (CDFR), including design codes, engineering components, materials and fuels development, chemical engineering/sodium technology, safety and reactor performance, is reviewed. The problems of PFR and CDFR fuel reprocessing are also discussed
Development of French programme on fast reactors, from March 1976 to March 1977
International Nuclear Information System (INIS)
Vautrey, L.
1977-01-01
The following milestones of the French LMFBR programme are reported: RAPSODIE (irradiation experiments in order to study the behaviour of the different fuel components of a sodium cooled fast reactor); PHENIX (the burn-up of the first core has reached the nominal value of 50,000MWD/T); SUPER-PHENIX (status of construction)
A review of the Italian fast reactor programme, March 1979
Energy Technology Data Exchange (ETDEWEB)
Pierantoni, F
1979-07-01
Year 1978 in Italy was marked by a standstill in the nuclear energy field. The decisions previously made for the installation of eight 1000 MWe LWR-type reactors could not be acted upon because of the opposition of local authorities and lack of Government power. The construction site at Montalto di Castro (two BWR reactors) was ope ned with difficulty, whereas the decision to install a plant in Mo use equipped with two PWR reactor was postponed. The new presidents of ENEL and CNEN were appointed in January this year and the appointments of the new Boards of Directors are underway. With regard to CNEN, many political bodies are in agreement on an institutional change which would widen field of activity to include new energy sources, solar energy in particular. This will open a big problem: if CNEN will be no more a 'nuclear body, it could be necessary to transfer all the activities connected to the Regulatory Commission to another separate body to be instituted. In this context, the fast reactor programme has continued to develop under the directives of CIPE, and has concentrated its effort on the following three objectives: the PEC-Reactor, the Creys-Malville Power Plant and research and development, and industrial promotion. These objectives are being pursued with the participation of CNEN, ENEL and Italian industry. CNEN has the role of committing and operating the PEC reactor; it is also charged to perform part of the R and D Italian-French programme and to promote industrial development. ENEL participates in the NERSA Company, owner of the Creys-Malville Plant. Italian industry, with its activities of architect-engineering, designing and manufacturing will participate in the construction of the PEC and of the Italian part (33%) of the Creys-Malville Plant. During the last months of 1978 a consortium (COREY) was set up by CNEN and NIRA which has the purpose of integrating and ensuring the smooth running of Italian efforts in the field of long-term research and
A review of the Italian fast reactor programme, March 1979
International Nuclear Information System (INIS)
Pierantoni, F.
1979-01-01
Year 1978 in Italy was marked by a standstill in the nuclear energy field. The decisions previously made for the installation of eight 1000 MWe LWR-type reactors could not be acted upon because of the opposition of local authorities and lack of Government power. The construction site at Montalto di Castro (two BWR reactors) was ope ned with difficulty, whereas the decision to install a plant in Mo use equipped with two PWR reactor was postponed. The new presidents of ENEL and CNEN were appointed in January this year and the appointments of the new Boards of Directors are underway. With regard to CNEN, many political bodies are in agreement on an institutional change which would widen field of activity to include new energy sources, solar energy in particular. This will open a big problem: if CNEN will be no more a 'nuclear body, it could be necessary to transfer all the activities connected to the Regulatory Commission to another separate body to be instituted. In this context, the fast reactor programme has continued to develop under the directives of CIPE, and has concentrated its effort on the following three objectives: the PEC-Reactor, the Creys-Malville Power Plant and research and development, and industrial promotion. These objectives are being pursued with the participation of CNEN, ENEL and Italian industry. CNEN has the role of committing and operating the PEC reactor; it is also charged to perform part of the R and D Italian-French programme and to promote industrial development. ENEL participates in the NERSA Company, owner of the Creys-Malville Plant. Italian industry, with its activities of architect-engineering, designing and manufacturing will participate in the construction of the PEC and of the Italian part (33%) of the Creys-Malville Plant. During the last months of 1978 a consortium (COREY) was set up by CNEN and NIRA which has the purpose of integrating and ensuring the smooth running of Italian efforts in the field of long-term research and
Review of fast reactor activities at OECD (NEA), March 1979
Energy Technology Data Exchange (ETDEWEB)
Royen, J
1979-07-01
continue to rise. These facts argue strongly not only for the continued development and commercial demonstration of the breeder, but also for the supporting services required to ensure its success. This report contains analysis of the following issues: gas cooled reactors; safety of LMFBRs, fast reactor physics; fast reactor nuclear data, and activities of the NEA Data Bank.
A review of fast reactor activities in Switzerland - March 1984
International Nuclear Information System (INIS)
Wydler, P.
1984-01-01
As a result of the noncentralized government in Switzerland there is no clear national policy for the future application of nuclear energy. This is reflected in the lack of a generally agreed nuclear energy research policy in the country. Consequently, activities related to several advanced reactor concepts are funded simultaneously at similar, but relatively low levels. The total expenditure of 5.9 million Swiss Francs (approx. 1 SFr per capita) for fast reactor activities in 1983 must be judged in the light of this situation. The funds have been allocated to an LMFBR safety programme (52%) and a fuel development programme (48%). In the field of LMFBR safety analytical work is performed on hypothetical core disruptive accidents (HCDAs) and on the integrity of components under HCDA loadings with emphasis on the dynamic behaviour of the reactor cover. A considerable effort has recently been devoted to the preparations for the SONACO natural convection experiment. Another relatively new experimental activity, involving small-scale vapour explosions with freon and water, has produced evidence of interesting physical effects which are not in accord with the assumptions of current molten fuel-coolant interaction (MFCI) models. The fuel development programme has continued with the manufacture of spherepac mixed carbide fuel pins for an irradiation experiment in FFTF. However, the time scale of the experiment has suffered a set-back due to an accident in a glove box of the production line
A review of fast reactor program in Japan. April 2000 - March 2001
International Nuclear Information System (INIS)
Nagata, Takashi; Yamashita, Hidetoshi
2001-01-01
This report describes the development and activities on fast reactors in Japan thru April 2000 to March 2001. During this period, the most important result of the Japanese Fast Reactor Project was that the first phase 'Feasibility Study on Commercialized Fast Reactor Cycle Systems' was completed at the end of March 2001, and the second phase study has just started in order to narrow down the candidate concepts selected in the first phase for next stage. In the Experimental Fast Reactor 'Joyo', the 35 th rated power operation was completed by the end of May 2000. The 13 th periodical inspection and reconstruction works for the Joyo upgrading program (MK-III) were started on the beginning of June 2000. The modification of the cooling system is underway. In the Prototype Fast Breeder Reactor 'Monju', countermeasures against sodium leakage have already been drawn up based on 'Monju' comprehensive safety review. The Japan Atomic Energy Commission (JAEC) has issued a new 'Long-term Program for Research, Development and Utilization of Nuclear Energy' in November 2000. (author)
Hanford environmental analytical methods (methods as of March 1990)
International Nuclear Information System (INIS)
Goheen, S.C.; McCulloch, M.; Daniel, J.L.
1993-05-01
Techniques in use at the Hanford Reservation as of March, 1990 for the analysis of liquids and radioactive effluents are described. Limitations and applications of the techniques are included. This report is Appendix A3-R
Hanford Environmental Analytical Methods (methods as of March 1990)
International Nuclear Information System (INIS)
Goheen, S.C.; McCulloch, M.; Daniel, J.L.
1993-05-01
Techniques in use at the Hanford Reservation as of March, 1990 for the analysis of liquids, organic wastes, soils, and sediments, are described. Limitations and applications of the techniques are included
Energy Technology Data Exchange (ETDEWEB)
Vautrey, L. [Commissariat a l' Energie Atomique, CEN de Saclay, Gif-sur-Yvette (France)
1981-05-15
This paper describes general features concerning development in the field of fast reactors in France from March 1980 to March 1981. It concentrates mainly on: Rapsodie, Phenix NPP, prototype reactor Super Phenix 1, future fast reactor NPPs and current research and development programs in the field. The present situation is as follows. Rapsodie has restarted operation but at reduced power in July 1980 because of the problems in the primary circuit which have not yet been solved. Phenic operates in a very satisfactory manner. Construction of Super Phenix is continuing normally. Research activities are performed sometimes for the needs of Super Phenix and sometimes for the needs of future fast rector projects like Super Phenix 2. International cooperation is being continued.
A review of fast reactor program in Japan. April 1997 - March 1998
International Nuclear Information System (INIS)
1998-01-01
This report describes the development and activities on fast reactor in Japan for the period of April 1997 - March 1998. During this period, two important results were drawn by the Special Committee on Fast Breeder Reactors (FBRs) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) Reform Committee, respectively. The Special Committee on FBRs discussed on the future FBR development in Japan including the Prototype FBR 'Monju' operation, and proposed its conclusion as the final report to the Japan Atomic Energy Commission (JAEC) on December 1, 1997. The PNC Reform Committee reviewed PNC's management and safety assurance system, and recommended to reform PNC to a new organization. Each committee result is outlined in this report. The Experimental Fast Reactor 'Joyo' operated 30th - 32nd cycle. In parallel with the operation, the Joyo Upgrading Program (MK-III program) is in progress. Five MK-III driver fuel subassemblies were loaded to the core in the 32nd cycle. Monju comprehensive safety review, which was started in December 1996, was continued through 1997, and was completed in March 1998. The DFBR Plant Optimization (phase 2) design study was launched by the Japan Atomic Power Company (JAPC) with goal of constructing FBR plant that achieves both reliability and economy from FY 1997 for three years. Research and development works are underway under the discussion and coordination of the Japanese FBR R and D Steering Committee, which is composed of PNC, JAPC, Japan Atomic Energy Research Institute (JAERI) and Central Research Institute of Electric Power Industry (CRIEPI). (author)
A review of fast reactor program in Japan (April 2001 - March 2002)
International Nuclear Information System (INIS)
Nagata, T.; Ieda, Y.
2002-01-01
This report describes the research and development activities on fast reactors in Japan thru April 2001 to March 2002. In December 2001, the Cabinet decided the Plan for Reorganization of Government-funded Corporations including the merger of JNC and the Japan Atomic Energy Research Institute (JAERI). A law to set up a new entity is supposed to be submitted to the National Diet by the Japanese Fiscal Year (JFY) 2004. In the Experimental Fast Reactor Joyo, thirty-five duty cycle operations and thirteen special tests with the MK-II core were completed by June 2000 without any fuel pin failures or serious plant trouble. The reactor is currently being upgraded to the MK-III core. Though a fire broke out in the maintenance building of Joyo in October 2001, the Mk-III construction work was restarted in February 2002. In the Prototype Fast Breeder Reactor Monju, countermeasures against sodium leakage have already been drawn up based on Monju comprehensive safety review. The safety licensing examination for the plant modification of Monju is undergoing. As for the Feasibility Study on Commercialized Fast Reactor Cycle Systems, JFY2001 was the first year of its second phase. A three-year period from JFY2001 to 2003 is the initial term of this phase. During this term, research activities are being focused on the design of the candidate concepts and fundamental tests of key technologies. An interim summary of these activities will be checked and reviewed, and based on the results; the research for JFY 2004 to 2005 will be conducted in order to narrow down the number of alternatives for the fast reactor cycle. (author)
Hu, Jiangtao; Cao, Junxing; Wang, Huazhong; Wang, Xingjian; Jiang, Xudong
2017-12-01
First-arrival traveltime computation for quasi-P waves in transversely isotropic (TI) media is the key component of tomography and depth migration. It is appealing to use the fast marching method in isotropic media as it efficiently computes traveltime along an expanding wavefront. It uses the finite difference method to solve the eikonal equation. However, applying the fast marching method in anisotropic media faces challenges because the anisotropy introduces additional nonlinearity in the eikonal equation and solving this nonlinear eikonal equation with the finite difference method is challenging. To address this problem, we present a Fermat’s principle-based fast marching method to compute traveltime in two-dimensional TI media. This method is applicable in both vertical and tilted TI (VTI and TTI) media. It computes traveltime along an expanding wavefront using Fermat’s principle instead of the eikonal equation. Thus, it does not suffer from the nonlinearity of the eikonal equation in TI media. To compute traveltime using Fermat’s principle, the explicit expression of group velocity in TI media is required to describe the ray propagation. The moveout approximation is adopted to obtain the explicit expression of group velocity. Numerical examples on both VTI and TTI models show that the traveltime contour obtained by the proposed method matches well with the wavefront from the wave equation. This shows that the proposed method could be used in depth migration and tomography.
Hanford environmental analytical methods (methods as of March 1990)
International Nuclear Information System (INIS)
Goheen, S.D.; McCulloch, M.; Daniel, J.L.
1993-05-01
Information is provided on the techniques employed towards the chemical analysis of volatile, semi-volatile matter, pesticides and PCB's at the Hanford Reservation. Sample preparation methods are included
Hanford environmental analytical methods: Methods as of March 1990
International Nuclear Information System (INIS)
Goheen, S.C.; McCulloch, M.; Daniel, J.L.
1993-05-01
This paper from the analytical laboratories at Hanford describes the method used to measure pH of single-shell tank core samples. Sludge or solid samples are mixed with deionized water. The pH electrode used combines both a sensor and reference electrode in one unit. The meter amplifies the input signal from the electrode and displays the pH visually
Efficient Methods for Fast Shading
Directory of Open Access Journals (Sweden)
ROMANYUK, A.
2008-06-01
Full Text Available On devices without battery consuming and specialized hardware for rendering, it is important to improve the speed and quality so that these methods are suitable for real-time rendering. Furthermore such algorithms are needed on the coming multicore architectures. We show how the methods by Gouraud and Phong, the commonly most used methods for shading, can be improved and made faster for both software rendering as well as simple low energy consuming hardware implementations. Moreover, this paper summarizes the authors' achievements in increasing shading speed and performance and a Bidirectional Reflectance Distribution Function is simplified for faster computing and hardware implementation.
Nodal method for fast reactor analysis
International Nuclear Information System (INIS)
Shober, R.A.
1979-01-01
In this paper, a nodal method applicable to fast reactor diffusion theory analysis has been developed. This method has been shown to be accurate and efficient in comparison to highly optimized finite difference techniques. The use of an analytic solution to the diffusion equation as a means of determining accurate coupling relationships between nodes has been shown to be highly accurate and efficient in specific two-group applications, as well as in the current multigroup method
A review of the U.K. fast reactor programme: March 1978
International Nuclear Information System (INIS)
Smith, R.D.
1978-01-01
The review of the UK fast reactor programme covers the description of Dounreay Fast Reactor shut down after seventeen years of successful operation; description of prototype fast reactor (PFR); core design parameters safety features and plant design for commercial demonstration fast reactor (CDFR). Engineering development is related to large sodium rigs, coolant circuit hydraulics and vibration, instrumentation and components. The subjects of interest are material development, sodium technology, fast reactor fuel, fuel cycle, reactor safety, reactor performance studies
A review of the U.K. fast reactor programme: March 1978
Energy Technology Data Exchange (ETDEWEB)
Smith, R D [United Kingdom Atomic Energy Authority, Risley (United Kingdom)
1978-07-01
The review of the UK fast reactor programme covers the description of Dounreay Fast Reactor shut down after seventeen years of successful operation; description of prototype fast reactor (PFR); core design parameters safety features and plant design for commercial demonstration fast reactor (CDFR). Engineering development is related to large sodium rigs, coolant circuit hydraulics and vibration, instrumentation and components. The subjects of interest are material development, sodium technology, fast reactor fuel, fuel cycle, reactor safety, reactor performance studies.
Directory of Open Access Journals (Sweden)
Trong-Ngoc Le
2016-01-01
Full Text Available Objective. Our objective is to develop a computerized scheme for liver tumor segmentation in MR images. Materials and Methods. Our proposed scheme consists of four main stages. Firstly, the region of interest (ROI image which contains the liver tumor region in the T1-weighted MR image series was extracted by using seed points. The noise in this ROI image was reduced and the boundaries were enhanced. A 3D fast marching algorithm was applied to generate the initial labeled regions which are considered as teacher regions. A single hidden layer feedforward neural network (SLFN, which was trained by a noniterative algorithm, was employed to classify the unlabeled voxels. Finally, the postprocessing stage was applied to extract and refine the liver tumor boundaries. The liver tumors determined by our scheme were compared with those manually traced by a radiologist, used as the “ground truth.” Results. The study was evaluated on two datasets of 25 tumors from 16 patients. The proposed scheme obtained the mean volumetric overlap error of 27.43% and the mean percentage volume error of 15.73%. The mean of the average surface distance, the root mean square surface distance, and the maximal surface distance were 0.58 mm, 1.20 mm, and 6.29 mm, respectively.
Commission of the European Communities review of fast reactor activities, March 1981
Energy Technology Data Exchange (ETDEWEB)
Balz, W [Commission of the European Communities, Brussels (Belgium)
1981-05-01
The Commission of the European Communities continued its activities in the field of fast reactors development essentially in the frame of the Fast Reactor Coordinating Committee (FRCC) and by execution of a Reactor Programme at its Joint Research Center (JRC). The study was concerned with introducing fast reactors into European Community, elaboration of preliminary safety criteria and guidelines for typical fast reactor accidents; codes and standards; LMFBR safety, fuel, fuel cycle safety.
Commission of the European Communities review of fast reactor activities, March 1981
International Nuclear Information System (INIS)
Balz, W.
1981-01-01
The Commission of the European Communities continued its activities in the field of fast reactors development essentially in the frame of the Fast Reactor Coordinating Committee (FRCC) and by execution of a Reactor Programme at its Joint Research Center (JRC). The study was concerned with introducing fast reactors into European Community, elaboration of preliminary safety criteria and guidelines for typical fast reactor accidents; codes and standards; LMFBR safety, fuel, fuel cycle safety
Status of fast reactor development in India (April 1996 - March 1997)
International Nuclear Information System (INIS)
Bhoje, S.B.
1998-01-01
India generated 395 TWh of electricity during, 4 April 1996 to March 1997. Oil import bill during the year was $9.3 billion. The operating performance of the thermal power reactors has considerably improved during the year and has enhanced the confidence level in nuclear energy in the government and the public. Construction of 4x220 MWe PHWR is continued at two locations. Start of construction of 2x220 MWe PHWR, 2x500 MWe PHWR and 2x1000 MWe WWER (Russian collaboration) and 500 MWe PFBR have been proposed in the IX Plan (1997- 2002). The 13 party coalition government is discussing the IX plan proposals in the power sector. Operation of FBTR at 10.5 MWt is continued The maximum fuel burnup reached is 32,000 MWd/t without any failure. Targeted burnup is 50,000 MWd/t. Post irradiation examination has been completed on one fuel subassembly taken out at 25,000 MWd/t. The performance of the fuel is very good. Turbine was rolled up to synchronous speed of 3000 rpm several times during the year and operation was found to be smooth. TG synchronisation with grid will be achieved during the reactor operation at 12.5 MWt, with the addition of fuel subassemblies in the core. All the activities related to the revision of conceptual design from 4 loop to 2 loop concept are almost complete for the 500 MWe Prototype Fast Breeder Reactor. The main options for the reactor are sodium coolant, pool type, MOX fuel, 2 primary sodium pumps, 2 secondary loops with 4 SG in each loop. The important design activities carried out during the year are plant dynamic studies, decay heat removal analysis, design of pump to grid plate pipe, scram and LOR parameters, location of secondary sodium pump in the secondary sodium circuit and design of fuel handling machines. Important experimental R and D work carried out during the year were testing of prototype primary sodium pump in water, operation of a large sodium test rig to study the heat and mass transfer in the cover gas, testing of dummy fuel
A review of the United Kingdom fast reactor programme - March 1984
International Nuclear Information System (INIS)
Smith, R.D.
1984-01-01
The UK programme in the field of fast reactors has continued successfully towards the following main objectives, details of which are contained in subsequent sections of this report: (a) Full power operation of the PFR. (b) Development work supporting the NNC designed CDFR. (c) Demonstration and development of the fast reactor fuel cycle
Commission of the European Communities - Review of fast reactor activities, March 1979
International Nuclear Information System (INIS)
Balz, W.
1979-01-01
The Commission of the European Communities pursued its activities on the lines described earlier. Besides the execution of a research programme in its Joint Research Centre the Commission endeavoured to support the development and demonstration of fast reactors. Most of the latter activities were performed in the frame of the Fast Reactor Coordinating Committee
Novel applications of fast neutron interrogation methods
International Nuclear Information System (INIS)
Gozani, Tsahi
1994-01-01
The development of non-intrusive inspection methods for contraband consisting primarily of carbon, nitrogen, oxygen, and hydrogen requires the use of fast neutrons. While most elements can be sufficiently well detected by the thermal neutron capture process, some important ones, e.g., carbon and in particular oxygen, cannot be detected by this process. Fortunately, fast neutrons, with energies above the threshold for inelastic scattering, stimulate relatively strong and specific gamma ray lines from these elements. The main lines are: 6.13 for O, 4.43 for C, and 5.11, 2.31 and 1.64 MeV for N. Accelerator-generated neutrons in the energy range of 7 to 15 MeV are being considered as interrogating radiations in a variety of non-intrusive inspection systems for contraband, from explosives to drugs and from coal to smuggled, dutiable goods. In some applications, mostly for inspection of small items such as luggage, the decision process involves a rudimentary imaging, akin to emission tomography, to obtain the localized concentration of various elements. This technique is called FNA - Fast Neutron Analysis. While this approach offers improvements over the TNA (Thermal Neutron Analysis), it is not applicable to large objects such as shipping containers and trucks. For these challenging applications, a collimated beam of neutrons is rastered along the height of the moving object. In addition, the neutrons are generated in very narrow nanosecond pulses. The point of their interaction inside the object is determined by the time of flight (TOF) method, that is measuring the time elapsed from the neutron generation to the time of detection of the stimulated gamma rays. This technique, called PFNA (Pulsed Fast Neutron Analysis), thus directly provides the elemental, and by inference, the chemical composition of the material at every volume element (voxel) of the object. The various neutron-based techniques are briefly described below. ((orig.))
A review of the United Kingdom fast reactor programme: March 1985
International Nuclear Information System (INIS)
Bramman, J.I.; John, C.T.; Wheeler, R.C.
1986-01-01
1984 was the most successful year so far in the history of the prototype fast reactor, and the one which is sustained at high power became possible for the first time. Generation reached the highest level between 12 August and 6 November. During 1984 there were some changes within the NNC from concentration on detail design, analysis and development in support of the CDFR. Nevertheless, most of the effort continued to be deployed on the CDFR, where the major activities have been preparation of the Design Concept Safety Report, analysis and development to establish the design and safety of the key feasibility topics and exploration of alternatives, notably plant layout and secondary containment design, to reduce cost. A further quantity of mixed (U, Pu) oxide fuel was reprocessed. Most of this material consisted of fuel fabrication residues but the opportunity was also taken to carry out trial dismantling, cropping and dissolution of some non-standard sub-assemblies containing wire-wrapped pins. A special small scale development cropper was tested on the wire-wrapped pins. The dismantling and cropping of, and fuel dissolution, from these sub-assemblies containing wire-wrapped pins was successfully demonstrated. The suitability for service of a structure can usually be established by a combination of validated calculation methods and experimental studies. Analyses invariably assume that the potential distortion modes and relevant damage processes are recognized, and this may not always be possible. The validation of a structure by experiments can prove to be difficult because of the costs of testing representative samples from a structure and of applying the load and environmental conditions which the sample would experience in service. A strategy for evaluating structures, even when theoretical and experimental difficulties arise, is now evolving. Increased emphasis is being placed on the solution of specific problems as contrasted with the development of generally
A review of the United Kingdom fast reactor programme: March 1987
International Nuclear Information System (INIS)
Bramman, J.I.; Wheeler, R.C.
1987-03-01
The UK fast reactor programme is reviewed under the following headings: Progress with PFR; Reprocessing; Commercial Design Studies: Structural Integrity; Engineering and Components; Materials; Sodium Chemistry; Core and Fuel; Safety; Plant Performance Studies. (U.K.)
Fast and accurate methods for phylogenomic analyses
Directory of Open Access Journals (Sweden)
Warnow Tandy
2011-10-01
Full Text Available Abstract Background Species phylogenies are not estimated directly, but rather through phylogenetic analyses of different gene datasets. However, true gene trees can differ from the true species tree (and hence from one another due to biological processes such as horizontal gene transfer, incomplete lineage sorting, and gene duplication and loss, so that no single gene tree is a reliable estimate of the species tree. Several methods have been developed to estimate species trees from estimated gene trees, differing according to the specific algorithmic technique used and the biological model used to explain differences between species and gene trees. Relatively little is known about the relative performance of these methods. Results We report on a study evaluating several different methods for estimating species trees from sequence datasets, simulating sequence evolution under a complex model including indels (insertions and deletions, substitutions, and incomplete lineage sorting. The most important finding of our study is that some fast and simple methods are nearly as accurate as the most accurate methods, which employ sophisticated statistical methods and are computationally quite intensive. We also observe that methods that explicitly consider errors in the estimated gene trees produce more accurate trees than methods that assume the estimated gene trees are correct. Conclusions Our study shows that highly accurate estimations of species trees are achievable, even when gene trees differ from each other and from the species tree, and that these estimations can be obtained using fairly simple and computationally tractable methods.
A Review of the United Kingdom Fast Reactor Programme, March 1987
International Nuclear Information System (INIS)
Bramman, J.I.; Wheeler, R.C.
1987-01-01
Nuclear power produced about 20% of the electricity supply in the United Kingdom in 1986, mostly from gas-cooled reactors, i.e. the 10 AGRs currently in operation and the 26 older MAGNOX reactors. Plans to increase the nuclear component of generating capacity by building the first PWR in the UK, Sizewell 'B', were strongly endorsed in the report by Sir Frank Layfield published on 26 January 1987. This resulted from the Public Inquiry into building Sizewell 'B', which was held between 11 January 1983 and 7 March 1985, the longest Public Inquiry ever held in the UK. The government gave the go-ahead for the building of Sizewell 'B' on 12 March 1987
FAST PALMPRINT AUTHENTICATION BY SOBEL CODE METHOD
Directory of Open Access Journals (Sweden)
Jyoti Malik
2011-05-01
Full Text Available The ideal real time personal authentication system should be fast and accurate to automatically identify a person’s identity. In this paper, we have proposed a palmprint based biometric authentication method with improvement in time and accuracy, so as to make it a real time palmprint authentication system. Several edge detection methods, wavelet transform, phase congruency etc. are available to extract line feature from the palmprint. In this paper, Multi-scale Sobel Code operators of different orientations (0?, 45?, 90?, and 135? are applied to the palmprint to extract Sobel-Palmprint features in different direc- tions. The Sobel-Palmprint features extracted are stored in Sobel- Palmprint feature vector and matched using sliding window with Hamming Distance similarity measurement method. The sliding win- dow method is accurate but time taking process. In this paper, we have improved the sliding window method so that the matching time reduces. It is observed that there is 39.36% improvement in matching time. In addition, a Min Max Threshold Range (MMTR method is proposed that helps in increasing overall system accuracy by reducing the False Acceptance Rate (FAR. Experimental results indicate that the MMTR method improves the False Acceptance Rate drastically and improvement in sliding window method reduces the comparison time. The accuracy improvement and matching time improvement leads to proposed real time authentication system.
Doublet method for very fast autocoding
Directory of Open Access Journals (Sweden)
Berman Jules J
2004-09-01
Full Text Available Abstract Background Autocoding (or automatic concept indexing occurs when a software program extracts terms contained within text and maps them to a standard list of concepts contained in a nomenclature. The purpose of autocoding is to provide a way of organizing large documents by the concepts represented in the text. Because textual data accumulates rapidly in biomedical institutions, the computational methods used to autocode text must be very fast. The purpose of this paper is to describe the doublet method, a new algorithm for very fast autocoding. Methods An autocoder was written that transforms plain-text into intercalated word doublets (e.g. "The ciliary body produces aqueous humor" becomes "The ciliary, ciliary body, body produces, produces aqueous, aqueous humor". Each doublet is checked against an index of doublets extracted from a standard nomenclature. Matching doublets are assigned a numeric code specific for each doublet found in the nomenclature. Text doublets that do not match the index of doublets extracted from the nomenclature are not part of valid nomenclature terms. Runs of matching doublets from text are concatenated and matched against nomenclature terms (also represented as runs of doublets. Results The doublet autocoder was compared for speed and performance against a previously published phrase autocoder. Both autocoders are Perl scripts, and both autocoders used an identical text (a 170+ Megabyte collection of abstracts collected through a PubMed search and the same nomenclature (neocl.xml, containing over 102,271 unique names of neoplasms. In side-by-side comparison on the same computer, the doublet method autocoder was 8.4 times faster than the phrase autocoder (211 seconds versus 1,776 seconds. The doublet method codes 0.8 Megabytes of text per second on a desktop computer with a 1.6 GHz processor. In addition, the doublet autocoder successfully matched terms that were missed by the phrase autocoder, while the
Scalable fast multipole accelerated vortex methods
Hu, Qi
2014-05-01
The fast multipole method (FMM) is often used to accelerate the calculation of particle interactions in particle-based methods to simulate incompressible flows. To evaluate the most time-consuming kernels - the Biot-Savart equation and stretching term of the vorticity equation, we mathematically reformulated it so that only two Laplace scalar potentials are used instead of six. This automatically ensuring divergence-free far-field computation. Based on this formulation, we developed a new FMM-based vortex method on heterogeneous architectures, which distributed the work between multicore CPUs and GPUs to best utilize the hardware resources and achieve excellent scalability. The algorithm uses new data structures which can dynamically manage inter-node communication and load balance efficiently, with only a small parallel construction overhead. This algorithm can scale to large-sized clusters showing both strong and weak scalability. Careful error and timing trade-off analysis are also performed for the cutoff functions induced by the vortex particle method. Our implementation can perform one time step of the velocity+stretching calculation for one billion particles on 32 nodes in 55.9 seconds, which yields 49.12 Tflop/s.
Progress report on fast breeder reactor development in Japan, June-March, 1979
International Nuclear Information System (INIS)
1979-11-01
The experimental fast reactor ''Joyo'' started the second cycle operation of 50 MW on January 12, and finished it on February 26. The operation was very stable throughout this period. The preparation to raise the output to 75 MW has been in progress since then in parallel with the periodic inspection. Experimental fuel subassemblies and a control rod used for the 50 MW operation were removed. Installations of a fuel storage and handling facility, a water cooling and purifying plant, and an in-water cutting equipment were completed. The works related to the analysis of the core characteristics are reported. The construction preliminary design (2) of the prototype fast reactor ''Monju'' was finished. The wind tunnel experiment and the calculation of earthquake response to artificial seismic waves are being carried on. The works of developing codes and the surveys on the construction site are reported. The fourth preliminary design of the demonstration fast reactor was completed. The research and development of reactor physics, structural components, instrumentation and control, sodium technology, fuel materials, structures and structural materials, safety and steam generators are reported. The technological investigation into foreign LMFBRs was finished. (Kako, I.)
Fast Prediction Method for Steady-State Heat Convection
Wá ng, Yì
2012-01-01
, the nonuniform POD-Galerkin projection method exhibits high accuracy, good suitability, and fast computation. It has universal significance for accurate and fast prediction. Also, the methodology can be applied to more complex modeling in chemical engineering
Status of Liquid Metal Fast Reactor Development in the United States of America, March 1987
International Nuclear Information System (INIS)
Horton, K.E.
1987-01-01
In order to meet the objective to develop and demonstrate economically competitive reactor designs and associated fuel cycles early in the next century, the U.S. program has become more focused. Two innovative reactor designs supported by the metal-fueled Integral Fast Reactor program are being directed at fulfilling a series of advanced reactor goals. The supporting technology programs and facilities are being refocused to support the overall goals. International collaboration is being broadened to provide the two-way support across the spectrum of plant projects and the fuel cycle. This program is intended to maintain the technology base into the time period (mid-1990s) when a private sector demonstration could be initiated. (author)
Performance Benchmarking of Fast Multipole Methods
Al-Harthi, Noha A.
2013-06-01
The current trends in computer architecture are shifting towards smaller byte/flop ratios, while available parallelism is increasing at all levels of granularity – vector length, core count, and MPI process. Intel’s Xeon Phi coprocessor, NVIDIA’s Kepler GPU, and IBM’s BlueGene/Q all have a Byte/flop ratio close to 0.2, which makes it very difficult for most algorithms to extract a high percentage of the theoretical peak flop/s from these architectures. Popular algorithms in scientific computing such as FFT are continuously evolving to keep up with this trend in hardware. In the meantime it is also necessary to invest in novel algorithms that are more suitable for computer architectures of the future. The fast multipole method (FMM) was originally developed as a fast algorithm for ap- proximating the N-body interactions that appear in astrophysics, molecular dynamics, and vortex based fluid dynamics simulations. The FMM possesses have a unique combination of being an efficient O(N) algorithm, while having an operational intensity that is higher than a matrix-matrix multiplication. In fact, the FMM can reduce the requirement of Byte/flop to around 0.01, which means that it will remain compute bound until 2020 even if the cur- rent trend in microprocessors continues. Despite these advantages, there have not been any benchmarks of FMM codes on modern architectures such as Xeon Phi, Kepler, and Blue- Gene/Q. This study aims to provide a comprehensive benchmark of a state of the art FMM code “exaFMM” on the latest architectures, in hopes of providing a useful reference for deciding when the FMM will become useful as the computational engine in a given application code. It may also serve as a warning to certain problem size domains areas where the FMM will exhibit insignificant performance improvements. Such issues depend strongly on the asymptotic constants rather than the asymptotics themselves, and therefore are strongly implementation and hardware
Status of fast reactor development in India. April 1998 - March 1999
International Nuclear Information System (INIS)
Lee, S.M.
1999-01-01
Electricity growth rate in India in 1998-99 improved compared to the previous year and the installed electric capacity reached 93.25 GWe. The thermal nuclear power plants performed very well with average capacity factor of over 72%. The Kalpakkam Reprocessing Plant was commissioned. FBTR was operated at various power levels and a peak fuel burn-up of 49000 MWd/t achieved. Test irradiation of Zr-Nb was undertaken in FBTR for the PHWR programme. Refurbishing of the plant included new state of the art neutronic channels. Detailed design of PFBR was continued. The review of the chapters of the PSAR by an IGCAR Internal Safety Committee and by the AERB PFBR-Project Design Safety Committee was continued. Work on Environmental Impact Assessment Report, for obtaining clearance from the concerned environmental authorities, for the project has been started Technology development for PFBR included core subassemblies, main vessel, inner vessel, IHX, steam generator, roof slab, drive mechanism, control plug etc. Indigenous manufacture of raw materials has been also taken up. R and D in reactor physics, shielding, engineering development, instrumentation, thermal hydraulics, structural mechanics, metallurgy, non-destructive examination, chemistry, reprocessing and safety was continued. These include cover gas heat and mass transfer, SA hydraulic tests, thermal striping studies, fuel development for PFBR, corrosion and material property studies on steels, PIE of FBTR fuel and developments for the pilot plant for fast reactor fuel reprocessing. (author)
Status of fast reactor development in India. April 1998 - March 1999
Energy Technology Data Exchange (ETDEWEB)
Lee, S M [Safety Research, Health Physics, Information Services, Instrumentation and Electronics Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu (India)
1999-07-01
Electricity growth rate in India in 1998-99 improved compared to the previous year and the installed electric capacity reached 93.25 GWe. The thermal nuclear power plants performed very well with average capacity factor of over 72%. The Kalpakkam Reprocessing Plant was commissioned. FBTR was operated at various power levels and a peak fuel burn-up of 49000 MWd/t achieved. Test irradiation of Zr-Nb was undertaken in FBTR for the PHWR programme. Refurbishing of the plant included new state of the art neutronic channels. Detailed design of PFBR was continued. The review of the chapters of the PSAR by an IGCAR Internal Safety Committee and by the AERB PFBR-Project Design Safety Committee was continued. Work on Environmental Impact Assessment Report, for obtaining clearance from the concerned environmental authorities, for the project has been started Technology development for PFBR included core subassemblies, main vessel, inner vessel, IHX, steam generator, roof slab, drive mechanism, control plug etc. Indigenous manufacture of raw materials has been also taken up. R and D in reactor physics, shielding, engineering development, instrumentation, thermal hydraulics, structural mechanics, metallurgy, non-destructive examination, chemistry, reprocessing and safety was continued. These include cover gas heat and mass transfer, SA hydraulic tests, thermal striping studies, fuel development for PFBR, corrosion and material property studies on steels, PIE of FBTR fuel and developments for the pilot plant for fast reactor fuel reprocessing. (author)
Scalable fast multipole methods for vortex element methods
Hu, Qi
2012-11-01
We use a particle-based method to simulate incompressible flows, where the Fast Multipole Method (FMM) is used to accelerate the calculation of particle interactions. The most time-consuming kernelsâ\\'the Biot-Savart equation and stretching term of the vorticity equationâ\\'are mathematically reformulated so that only two Laplace scalar potentials are used instead of six, while automatically ensuring divergence-free far-field computation. Based on this formulation, and on our previous work for a scalar heterogeneous FMM algorithm, we develop a new FMM-based vortex method capable of simulating general flows including turbulence on heterogeneous architectures, which distributes the work between multi-core CPUs and GPUs to best utilize the hardware resources and achieve excellent scalability. The algorithm also uses new data structures which can dynamically manage inter-node communication and load balance efficiently but with only a small parallel construction overhead. This algorithm can scale to large-sized clusters showing both strong and weak scalability. Careful error and timing trade-off analysis are also performed for the cutoff functions induced by the vortex particle method. Our implementation can perform one time step of the velocity+stretching for one billion particles on 32 nodes in 55.9 seconds, which yields 49.12 Tflop/s. © 2012 IEEE.
Scalable force directed graph layout algorithms using fast multipole methods
Yunis, Enas Abdulrahman; Yokota, Rio; Ahmadia, Aron
2012-01-01
We present an extension to ExaFMM, a Fast Multipole Method library, as a generalized approach for fast and scalable execution of the Force-Directed Graph Layout algorithm. The Force-Directed Graph Layout algorithm is a physics-based approach
A task parallel implementation of fast multipole methods
Taura, Kenjiro; Nakashima, Jun; Yokota, Rio; Maruyama, Naoya
2012-01-01
This paper describes a task parallel implementation of ExaFMM, an open source implementation of fast multipole methods (FMM), using a lightweight task parallel library MassiveThreads. Although there have been many attempts on parallelizing FMM
A Fast and Robust Method for Measuring Optical Channel Gain
DEFF Research Database (Denmark)
Harbo, Anders La-Cour; Stoustrup, Jakob; Villemoes, L.F.
2000-01-01
We present a numerically stable and computational simple method for fast and robust measurement of optical channel gain. By transmitting adaptively designed signals through the channel, good accuracy is possible even in severe noise conditions......We present a numerically stable and computational simple method for fast and robust measurement of optical channel gain. By transmitting adaptively designed signals through the channel, good accuracy is possible even in severe noise conditions...
Fast linear method of illumination classification
Cooper, Ted J.; Baqai, Farhan A.
2003-01-01
We present a simple method for estimating the scene illuminant for images obtained by a Digital Still Camera (DSC). The proposed method utilizes basis vectors obtained from known memory color reflectance to identify the memory color objects in the image. Once the memory color pixels are identified, we use the ratios of the red/green and blue/green to determine the most likely illuminant in the image. The critical part of the method is to estimate the smallest set of basis vectors that closely represent the memory color reflectances. Basis vectors obtained from both Principal Component Analysis (PCA) and Independent Component Analysis (ICA) are used. We will show that only two ICA basis vectors are needed to get an acceptable estimate.
Fast Multilevel Panel Method for Wind Turbine Rotor Flow Simulations
van Garrel, Arne; Venner, Cornelis H.; Hoeijmakers, Hendrik Willem Marie
2017-01-01
A fast multilevel integral transform method has been developed that enables the rapid analysis of unsteady inviscid flows around wind turbines rotors. A low order panel method is used and the new multi-level multi-integration cluster (MLMIC) method reduces the computational complexity for
A fast method for optimal reactive power flow solution
Energy Technology Data Exchange (ETDEWEB)
Sadasivam, G; Khan, M A [Anna Univ., Madras (IN). Coll. of Engineering
1990-01-01
A fast successive linear programming (SLP) method for minimizing transmission losses and improving the voltage profile is proposed. The method uses the same compactly stored, factorized constant matrices in all the LP steps, both for power flow solution and for constructing the LP model. The inherent oscillatory convergence of SLP methods is overcome by proper selection of initial step sizes and their gradual reduction. Detailed studies on three systems, including a 109-bus system, reveal the fast and reliable convergence property of the method. (author).
Fast sequential Monte Carlo methods for counting and optimization
Rubinstein, Reuven Y; Vaisman, Radislav
2013-01-01
A comprehensive account of the theory and application of Monte Carlo methods Based on years of research in efficient Monte Carlo methods for estimation of rare-event probabilities, counting problems, and combinatorial optimization, Fast Sequential Monte Carlo Methods for Counting and Optimization is a complete illustration of fast sequential Monte Carlo techniques. The book provides an accessible overview of current work in the field of Monte Carlo methods, specifically sequential Monte Carlo techniques, for solving abstract counting and optimization problems. Written by authorities in the
Fast-timing methods for semiconductor detectors
International Nuclear Information System (INIS)
Spieler, H.
1982-03-01
The basic parameters are discussed which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter
Fast timing methods for semiconductor detectors. Revision
International Nuclear Information System (INIS)
Spieler, H.
1984-10-01
This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifically timing with thin-surface barrier detectors. The discussion focusses on properties of the detector, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, noiseless input terminations in sub-nanosecond preamplifiers and methods using transmission lines to couple the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effective rise time, equivalent input noise and residual jitter
Fast Implicit Methods For Elliptic Moving Interface Problems
2015-12-11
surfaces [30], and has recently been employed in the geometric nonuniform fast Fourier transform [12] and in the finite element method [31]. We employ...analyzed, and tested for the Fourier transform of piecewise polynomials given on d-dimensional simplices in D-dimensional Euclidean space. These transforms ...evaluation, and one to three orders of magnitude slower than the classical uniform Fast Fourier Transform . Second, bilinear quadratures ---which
New method of fast simulation for a hadron calorimeter response
International Nuclear Information System (INIS)
Kul'chitskij, Yu.; Sutiak, J.; Tokar, S.; Zenis, T.
2003-01-01
In this work we present the new method of a fast Monte-Carlo simulation of a hadron calorimeter response. It is based on the three-dimensional parameterization of the hadronic shower obtained from the ATLAS TILECAL test beam data and GEANT simulations. A new approach of including the longitudinal fluctuations of hadronic shower is described. The obtained results of the fast simulation are in good agreement with the TILECAL experimental data
Fast New Method for Temporary Chemical Passivation
Directory of Open Access Journals (Sweden)
Marek Solčanský
2012-12-01
Full Text Available The main material parameter of silicon, that influences the effectiveness of photovoltaic cells, is the minority carrier bulk lifetime.It may change in the technological process especially during high temperature operations. Monitoring of the carrier bulk-lifetimeis necessary for modifying the whole technological process of production. For the measurement of the minority carrier bulk-lifetimethe characterization method MW PCD (Microwave Photoconductance Decay is used, where the result of measurement is the effectivecarrier lifetime, which is very dependent on the surface recombination velocity and therefore on the quality of a silicon surfacepassivation.This work deals with an examination of a different solution types for the chemical passivation of a silicon surface. Varioussolutions are tested on silicon wafers for their consequent comparison. The main purpose of this work is to find optimal solution, whichsuits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibilityof a perfect cleaning of a passivating solution remains from a silicon surface. Another purpose of this work is to identify the parametersof other quinhydrone solutions with different concentrations as compared with the quinhydrone solution in methanol witha concentration of 0.07 mol/dm³ marked QM007 (referential solution.The method of an effective chemical passivation with a quinhydrone in methanol solution was suggested. The solution witha concentration of 0.07 mol /dm3 fulfills all required criteria. The work also confirms the influence of increased concentrationquinhydrone on the temporal stability of the passivation layer and the effect for textured silicon wafers. In conclusion, the influenceof an illumination and the temperature on the properties of the passivating solution QM007 is discussed.
Fast Detection Method in Cooperative Cognitive Radio Networks
Directory of Open Access Journals (Sweden)
Zhengyi Li
2010-01-01
Full Text Available Cognitive Radio (CR technology improves the utilization of spectrum highly via opportunistic spectrum sharing, which requests fast detection as the spectrum utilization is dynamic. Taking into consideration the characteristic of wireless channels, we propose a fast detection scheme for a cooperative cognitive radio network, which consists of multiple CRs and a central control office. Specifically, each CR makes individual detection decision using the sequential probability ratio test combined with Neyman Pearson detection with respect to a specific observation window length. The proposed method upper bounds the detection delay. In addition, a weighted K out of N fusion rule is also proposed for the central control office to reach fast global decision based on the information collected from CRs, with more weights assigned for CRs with good channel conditions. Simulation results show that the proposed scheme can achieve fast detection while maintaining the detection accuracy.
Explicit time marching methods for the time-dependent Euler computations
International Nuclear Information System (INIS)
Tai, C.H.; Chiang, D.C.; Su, Y.P.
1997-01-01
Four explicit type time marching methods, including one proposed by the authors, are examined. The TVD conditions of this method are analyzed with the linear conservation law as the model equation. Performance of these methods when applied to the Euler equations are numerically tested. Seven examples are tested, the main concern is the performance of the methods when discontinuities with different strengths are encountered. When the discontinuity is getting stronger, spurious oscillation shows up for three existing methods, while the method proposed by the authors always gives the results with satisfaction. The effect of the limiter is also investigated. To put these methods in the same basis for the comparison the same spatial discretization is used. Roe's solver is used to evaluate the fluxes at the cell interface; spatially second-order accuracy is achieved by the MUSCL reconstruction. 19 refs., 8 figs
An improved fast neutron radiography quantitative measurement method
International Nuclear Information System (INIS)
Matsubayashi, Masahito; Hibiki, Takashi; Mishima, Kaichiro; Yoshii, Koji; Okamoto, Koji
2004-01-01
The validity of a fast neutron radiography quantification method, the Σ-scaling method, which was originally proposed for thermal neutron radiography was examined with Monte Carlo calculations and experiments conducted at the YAYOI fast neutron source reactor. Water and copper were selected as comparative samples for a thermal neutron radiography case and a dense object, respectively. Although different characteristics on effective macroscopic cross-sections were implied by the simulation, the Σ-scaled experimental results with the fission neutron spectrum cross-sections were well fitted to the measurements for both the water and copper samples. This indicates that the Σ-scaling method could be successfully adopted for quantitative measurements in fast neutron radiography
A Fast LMMSE Channel Estimation Method for OFDM Systems
Directory of Open Access Journals (Sweden)
Zhou Wen
2009-01-01
Full Text Available A fast linear minimum mean square error (LMMSE channel estimation method has been proposed for Orthogonal Frequency Division Multiplexing (OFDM systems. In comparison with the conventional LMMSE channel estimation, the proposed channel estimation method does not require the statistic knowledge of the channel in advance and avoids the inverse operation of a large dimension matrix by using the fast Fourier transform (FFT operation. Therefore, the computational complexity can be reduced significantly. The normalized mean square errors (NMSEs of the proposed method and the conventional LMMSE estimation have been derived. Numerical results show that the NMSE of the proposed method is very close to that of the conventional LMMSE method, which is also verified by computer simulation. In addition, computer simulation shows that the performance of the proposed method is almost the same with that of the conventional LMMSE method in terms of bit error rate (BER.
Comparison of Standard and Fast Charging Methods for Electric Vehicles
Directory of Open Access Journals (Sweden)
Petr Chlebis
2014-01-01
Full Text Available This paper describes a comparison of standard and fast charging methods used in the field of electric vehicles and also comparison of their efficiency in terms of electrical energy consumption. The comparison was performed on three-phase buck converter, which was designed for EV’s fast charging station. The results were obtained by both mathematical and simulation methods. The laboratory model of entire physical application, which will be further used for simulation results verification, is being built in these days.
Influence function method for fast estimation of BWR core performance
International Nuclear Information System (INIS)
Rahnema, F.; Martin, C.L.; Parkos, G.R.; Williams, R.D.
1993-01-01
The model, which is based on the influence function method, provides rapid estimate of important quantities such as margins to fuel operating limits, the effective multiplication factor, nodal power and void and bundle flow distributions as well as the traversing in-core probe (TIP) and local power range monitor (LPRM) readings. The fast model has been incorporated into GE's three-dimensional core monitoring system (3D Monicore). In addition to its predicative capability, the model adapts to LPRM readings in the monitoring mode. Comparisons have shown that the agreement between the results of the fast method and those of the standard 3D Monicore is within a few percent. (orig.)
Fast method and ultra fast screening for determination of 90Sr in milk and dairy products
International Nuclear Information System (INIS)
Kabai, E.; Hornung, L.; Savkin, B.T.; Poppitz-Spuhler, A.; Hiersche, L.
2011-01-01
In emergency situation or in case of defence against nuclear hazards, the rapid analysis of radioisotopes in food products is essential. Radiostrontium is one of the most interesting isotopes in case of emergency. The determination of radiostrontium in milk and dairy products plays an important role especially for infants. The procedures described here were tested for fast determination of 90 Sr. The typical chemical recovery of the proposed fast procedure for determination of strontium from milk and dairy products was 90% and the time needed for analysis was one working day. The achieved detection limit for milk is 0.8 Bq/l. An ultra fast screening method allows the determination of radiostrontium with quantitative recovery within 1 hour. The minimum detectable activity in this case is 230 Bq/l.
A fast resonance interference treatment scheme with subgroup method
International Nuclear Information System (INIS)
Cao, L.; He, Q.; Wu, H.; Zu, T.; Shen, W.
2015-01-01
A fast Resonance Interference Factor (RIF) scheme is proposed to treat the resonance interference effects between different resonance nuclides. This scheme utilizes the conventional subgroup method to evaluate the self-shielded cross sections of the dominant resonance nuclide in the heterogeneous system and the hyper-fine energy group method to represent the resonance interference effects in a simplified homogeneous model. In this paper, the newly implemented scheme is compared to the background iteration scheme, the Resonance Nuclide Group (RNG) scheme and the conventional RIF scheme. The numerical results show that the errors of the effective self-shielded cross sections are significantly reduced by the fast RIF scheme compared with the background iteration scheme and the RNG scheme. Besides, the fast RIF scheme consumes less computation time than the conventional RIF schemes. The speed-up ratio is ~4.5 for MOX pin cell problems. (author)
Non-linear programming method in optimization of fast reactors
International Nuclear Information System (INIS)
Pavelesku, M.; Dumitresku, Kh.; Adam, S.
1975-01-01
Application of the non-linear programming methods on optimization of nuclear materials distribution in fast reactor is discussed. The programming task composition is made on the basis of the reactor calculation dependent on the fuel distribution strategy. As an illustration of this method application the solution of simple example is given. Solution of the non-linear program is done on the basis of the numerical method SUMT. (I.T.)
Thermal-hydraulic methods in fast reactor safety
International Nuclear Information System (INIS)
Weber, D.P.; Briggs, L.L.
1985-01-01
Methods for the solution of thermal-hydraulic problems in liquid metal fast breeder reactors (LMFBRs) arising primarily from transient accident analysis are reviewed. Principal emphasis is given to the important phenomenological issues of sodium boiling and fuel motion. Descriptions of representative phenomenological and mathematical models, computational algorithms, advantages and limitations of the approaches, and current research needs and directions are provided
Fast and sensitive method for detecting volatile species in liquids
DEFF Research Database (Denmark)
Trimarco, Daniel Bøndergaard; Pedersen, Thomas; Hansen, Ole
2015-01-01
to a mass spectrometer through a narrow capillary without the use of differential pumping. This method inherits features from differential electrochemical mass spectrometry (DEMS) and membrane inlet mass spectrometry (MIMS), but brings the best of both worlds, i.e., the fast time-response of a DEMS system...
A fast method for linear waves based on geometrical optics
Stolk, C.C.
2009-01-01
We develop a fast method for solving the one-dimensional wave equation based on geometrical optics. From geometrical optics (e.g., Fourier integral operator theory or WKB approximation) it is known that high-frequency waves split into forward and backward propagating parts, each propagating with the
Improved Multilevel Fast Multipole Method for Higher-Order discretizations
DEFF Research Database (Denmark)
Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik
2014-01-01
The Multilevel Fast Multipole Method (MLFMM) allows for a reduced computational complexity when solving electromagnetic scattering problems. Combining this with the reduced number of unknowns provided by Higher-Order discretizations has proven to be a difficult task, with the general conclusion b...
Fast Prediction Method for Steady-State Heat Convection
Wáng, Yì
2012-03-14
A reduced model by proper orthogonal decomposition (POD) and Galerkin projection methods for steady-state heat convection is established on a nonuniform grid. It was verified by thousands of examples that the results are in good agreement with the results obtained from the finite volume method. This model can also predict the cases where model parameters far exceed the sample scope. Moreover, the calculation time needed by the model is much shorter than that needed for the finite volume method. Thus, the nonuniform POD-Galerkin projection method exhibits high accuracy, good suitability, and fast computation. It has universal significance for accurate and fast prediction. Also, the methodology can be applied to more complex modeling in chemical engineering and technology, such as reaction and turbulence. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Symmetrized neutron transport equation and the fast Fourier transform method
International Nuclear Information System (INIS)
Sinh, N.Q.; Kisynski, J.; Mika, J.
1978-01-01
The differential equation obtained from the neutron transport equation by the application of the source iteration method in two-dimensional rectangular geometry is transformed into a symmetrized form with respect to one of the angular variables. The discretization of the symmetrized equation leads to finite difference equations based on the five-point scheme and solved by use of the fast Fourier transform method. Possible advantages of the approach are shown on test calculations
Real time simulation method for fast breeder reactors dynamics
International Nuclear Information System (INIS)
Miki, Tetsushi; Mineo, Yoshiyuki; Ogino, Takamichi; Kishida, Koji; Furuichi, Kenji.
1985-01-01
The development of multi-purpose real time simulator models with suitable plant dynamics was made; these models can be used not only in training operators but also in designing control systems, operation sequences and many other items which must be studied for the development of new type reactors. The prototype fast breeder reactor ''Monju'' is taken as an example. Analysis is made on various factors affecting the accuracy and computer load of its dynamic simulation. A method is presented which determines the optimum number of nodes in distributed systems and time steps. The oscillations due to the numerical instability are observed in the dynamic simulation of evaporators with a small number of nodes, and a method to cancel these oscillations is proposed. It has been verified through the development of plant dynamics simulation codes that these methods can provide efficient real time dynamics models of fast breeder reactors. (author)
Scalable fast multipole methods for vortex element methods
Hu, Qi; Gumerov, Nail A.; Yokota, Rio; Barba, Lorena A.; Duraiswami, Ramani
2012-01-01
work for a scalar heterogeneous FMM algorithm, we develop a new FMM-based vortex method capable of simulating general flows including turbulence on heterogeneous architectures, which distributes the work between multi-core CPUs and GPUs to best utilize
Steffen, Nicolle Olivia; Lance, Keith Curry; Lietzau, Zeth; Dickenson, Don
2005-01-01
Eleven issues of "Fast Facts" from the Library Research Service cover information from libraries across Colorado. These issues focus on topics from the public, academic, and school sectors. These topics include patron use of AskColorado (a statewide virtual reference service) and the rising use of online services. The "Fast…
Asynchronous Execution of the Fast Multipole Method Using Charm++
AbdulJabbar, Mustafa; Yokota, Rio; Keyes, David
2014-01-01
Fast multipole methods (FMM) on distributed mem- ory have traditionally used a bulk-synchronous model of com- municating the local essential tree (LET) and overlapping it with computation of the local data. This could be perceived as an extreme case of data aggregation, where the whole LET is communicated at once. Charm++ allows a much finer control over the granularity of communication, and has a asynchronous execution model that fits well with the structure of our FMM code. Unlike previous ...
International Nuclear Information System (INIS)
1987-07-01
The Agenda of the meeting was as follows: 1. Approval of the Agenda. 2. Approval of the minutes of the 19th meeting of the IWGFR. 3. Report of the Scientific Secretary regarding the WD activities of the Working Group. 4. Presentations and discussions on national programmes on fast breeder reactors. 5. Consideration of conferences on fast breeder reactors. a. ANS-ENS International Conference on Fast Breeder Systems Experience Gained and Path to Economical Power Generation, Richland, Washington, USA, 13-17 September 1987. b. International Conference on Liquid Metal Engineering and Technology, Avignon, France, 17-20 October 1988. c. Other meetings of interest to IWGFR members. 6. Consideration of major recommendations of some of the WD IWGFR Specialists' Meetings. 7. Consideration of arrangements for Specialists' Meetings in 1987. a. Specialists' Meeting on Fission and Corrosion Products Behaviour in Primary Circuits of LMFBRs, Karlsruhe, Fed. Rep. of Germany, May 1987. b. Specialists' Meeting on LMFBR Reactor Block Antiseismic Design and Verification, Bologna, Italy, October 1987. 8. Selection of topics for Specialists' Meetings to be held in 1988 and suggestions of the IWGFR on other Specialists' Meetings and their justifications. 9. Consideration of joint research activities: a. Coordinated Research Programme on a Comparative Assessment of Processing Techniques for Analysis of Sodium Boiling Noise Detection Data. b. Coordinated Research Programme on Intercomparison of LMFBR Core Mechanics Codes. c. New Topics of CRP. d. Other Activities. 10. Updating of ''LMFBR Plant Parameters''. 11. Informal discussion on ''Safety Criteria for Fast Reactors in IWGFR Countries''. 12. The date and place of the 21th Annual Meeting of the IWGFR
Fast computation of the characteristics method on vector computers
International Nuclear Information System (INIS)
Kugo, Teruhiko
2001-11-01
Fast computation of the characteristics method to solve the neutron transport equation in a heterogeneous geometry has been studied. Two vector computation algorithms; an odd-even sweep (OES) method and an independent sequential sweep (ISS) method have been developed and their efficiency to a typical fuel assembly calculation has been investigated. For both methods, a vector computation is 15 times faster than a scalar computation. From a viewpoint of comparison between the OES and ISS methods, the followings are found: 1) there is a small difference in a computation speed, 2) the ISS method shows a faster convergence and 3) the ISS method saves about 80% of computer memory size compared with the OES method. It is, therefore, concluded that the ISS method is superior to the OES method as a vectorization method. In the vector computation, a table-look-up method to reduce computation time of an exponential function saves only 20% of a whole computation time. Both the coarse mesh rebalance method and the Aitken acceleration method are effective as acceleration methods for the characteristics method, a combination of them saves 70-80% of outer iterations compared with a free iteration. (author)
Development of probabilistic fast reactor fuel design method
International Nuclear Information System (INIS)
Ozawa, Takayuki
1997-01-01
Under the current method of evaluating fuel robustness in FBR fuel rod design, a variety of uncertain quantities including fuel production tolerance and power density are estimated conservatively. In the future, in order to proceed with improvements in the FBR core's performance and optimize the fuel's specifications, a rationalization of fuel design tolerance is required. Among the measures aimed at realizing this rationalization, the introduction of a probabilistic fast reactor fuel design method is currently under consideration. I have developed a probabilistic fast reactor fuel design code named BORNFREE, in order to make use of this method in FBR fuel design. At the same time, I have carried out a trial calculation of the cladding stress using this code and made a study and an evaluation of the possibility of employing tolerance rationalization in fuel rod design. In this paper, I provide an outline description of BORNFREE and report the results of the above study and evaluation. After performing cladding stress trial calculations using the probabilistic method, I was able to confirm that this method promises more rational design evaluation results than the conventional deterministic method. (author)
Fast sweeping method for the factored eikonal equation
Fomel, Sergey; Luo, Songting; Zhao, Hongkai
2009-09-01
We develop a fast sweeping method for the factored eikonal equation. By decomposing the solution of a general eikonal equation as the product of two factors: the first factor is the solution to a simple eikonal equation (such as distance) or a previously computed solution to an approximate eikonal equation. The second factor is a necessary modification/correction. Appropriate discretization and a fast sweeping strategy are designed for the equation of the correction part. The key idea is to enforce the causality of the original eikonal equation during the Gauss-Seidel iterations. Using extensive numerical examples we demonstrate that (1) the convergence behavior of the fast sweeping method for the factored eikonal equation is the same as for the original eikonal equation, i.e., the number of iterations for the Gauss-Seidel iterations is independent of the mesh size, (2) the numerical solution from the factored eikonal equation is more accurate than the numerical solution directly computed from the original eikonal equation, especially for point sources.
Scalable force directed graph layout algorithms using fast multipole methods
Yunis, Enas Abdulrahman
2012-06-01
We present an extension to ExaFMM, a Fast Multipole Method library, as a generalized approach for fast and scalable execution of the Force-Directed Graph Layout algorithm. The Force-Directed Graph Layout algorithm is a physics-based approach to graph layout that treats the vertices V as repelling charged particles with the edges E connecting them acting as springs. Traditionally, the amount of work required in applying the Force-Directed Graph Layout algorithm is O(|V|2 + |E|) using direct calculations and O(|V| log |V| + |E|) using truncation, filtering, and/or multi-level techniques. Correct application of the Fast Multipole Method allows us to maintain a lower complexity of O(|V| + |E|) while regaining most of the precision lost in other techniques. Solving layout problems for truly large graphs with millions of vertices still requires a scalable algorithm and implementation. We have been able to leverage the scalability and architectural adaptability of the ExaFMM library to create a Force-Directed Graph Layout implementation that runs efficiently on distributed multicore and multi-GPU architectures. © 2012 IEEE.
Methods and tools to detect thermal noise in fast reactors
International Nuclear Information System (INIS)
Motta, M.; Giovannini, R.
1985-07-01
The Specialists' Meeting on ''Methods and Tools to Detect Thermal Noise in Fast Reactors'' was held in Bologna on 8-10 October 1984. The meeting was hosted by the ENEA and was sponsored by the IAEA on the recommendation of the International Working Group on Fast Reactors. 17 participants attended the meeting from France, the Federal Republic of Germany, Italy, Japan, the United Kingdom, Joint Research Centre of CEC and from IAEA. The meeting was presided over by Prof. Mario Motta of Italy. The purpose of the meeting was to review and discuss methods and tools for temperature noise detection and related analysis as a potential means for detecting local blockages in fuel and blanket subassemblies and other faults in LMFBR. The meeting was divided into four technical sessions as follows: 1. National review presentations on application purposes and research activities for thermal noise detection. (5 papers); 2. Detection instruments and electronic equipment for temperature measurements in fast reactors. (5 papers); 3. Physical models. (2 papers); 4. Signal processing techniques. (3 papers). A separate abstract was prepared for each of these papers
Methods for the sodium cooled fast reactor fire safety provisions
International Nuclear Information System (INIS)
Gryaznov, B.V.; Dergachev, N.P.
1983-01-01
Problems of fire safety provision on NPPs with sodium cooled fast reactor are under discussion. Methods of sodium leak localization, measures eliminating sodium flaring up during leaks and main means of sodium fire extinguishing are considered. An extinguishing of sodium flaring up is performed by means of sodium temperatUre decrease and by limitation of hydrogen access to the flaring up surface. A conclusion is made that the most effective methods of extinguishing are the following: self-extinguishing (due to hydrogen burning out in a limiting volume); extinguishing by a gas mixture of nitrogen and carbonic acid (initial filling and blowing of rooms during sodium flaring up); extinguishing by special powders
Parabolic approximation method for fast magnetosonic wave propagation in tokamaks
International Nuclear Information System (INIS)
Phillips, C.K.; Perkins, F.W.; Hwang, D.Q.
1985-07-01
Fast magnetosonic wave propagation in a cylindrical tokamak model is studied using a parabolic approximation method in which poloidal variations of the wave field are considered weak in comparison to the radial variations. Diffraction effects, which are ignored by ray tracing mthods, are included self-consistently using the parabolic method since continuous representations for the wave electromagnetic fields are computed directly. Numerical results are presented which illustrate the cylindrical convergence of the launched waves into a diffraction-limited focal spot on the cyclotron absorption layer near the magnetic axis for a wide range of plasma confinement parameters
Energy Technology Data Exchange (ETDEWEB)
Kirtley, K.R.
1988-10-01
A new coupled parabolic-marching method was developed to solve the three-dimensional incompressible Navier-Stokes equation for turbulent turbomachinery flows. Earlier space-marching methods were analyzed to determine their global stability during multiple passes of the computational domain. The methods were found to be unconditionally unstable even when an extra equation for the pressure, namely the Poisson equation for the pressure, was used between passes of the domain. Relaxation of one constraint during the solution process was found to be necessary for the successful calculation of a complex flow.Thus, the method of pseudocompressibility was introduced into the partially parabolized Navier-Stokes equation to relax the mass flow constraint during a forward-marching integration as well as globally stable during successive passes of the domain. With consistent discretization, the new method was found to be convergent.
Fourier-Based Fast Multipole Method for the Helmholtz Equation
Cecka, Cris
2013-01-01
The fast multipole method (FMM) has had great success in reducing the computational complexity of solving the boundary integral form of the Helmholtz equation. We present a formulation of the Helmholtz FMM that uses Fourier basis functions rather than spherical harmonics. By modifying the transfer function in the precomputation stage of the FMM, time-critical stages of the algorithm are accelerated by causing the interpolation operators to become straightforward applications of fast Fourier transforms, retaining the diagonality of the transfer function, and providing a simplified error analysis. Using Fourier analysis, constructive algorithms are derived to a priori determine an integration quadrature for a given error tolerance. Sharp error bounds are derived and verified numerically. Various optimizations are considered to reduce the number of quadrature points and reduce the cost of computing the transfer function. © 2013 Society for Industrial and Applied Mathematics.
Method for integrating a train of fast, nanosecond wide pulses
International Nuclear Information System (INIS)
Rose, C.R.
1987-01-01
This paper describes a method used to integrate a train of fast, nanosecond wide pulses. The pulses come from current transformers in a RF LINAC beamline. Because they are ac signals and have no dc component, true mathematical integration would yield zero over the pulse train period or an equally erroneous value because of a dc baseline shift. The circuit used to integrate the pulse train first stretches the pulses to 35 ns FWHM. The signals are then fed into a high-speed, precision rectifier which restores a true dc baseline for the following stage - a fast, gated integrator. The rectifier is linear over 55dB in excess of 25 MHz, and the gated integrator is linear over a 60 dB range with input pulse widths as short as 16 ns. The assembled system is linear over 30 dB with a 6 MHz input signal
Parallel Fast Multipole Boundary Element Method for crustal dynamics
International Nuclear Information System (INIS)
Quevedo, Leonardo; Morra, Gabriele; Mueller, R Dietmar
2010-01-01
Crustal faults and sharp material transitions in the crust are usually represented as triangulated surfaces in structural geological models. The complex range of volumes separating such surfaces is typically three-dimensionally meshed in order to solve equations that describe crustal deformation with the finite-difference (FD) or finite-element (FEM) methods. We show here how the Boundary Element Method, combined with the Multipole approach, can revolutionise the calculation of stress and strain, solving the problem of computational scalability from reservoir to basin scales. The Fast Multipole Boundary Element Method (Fast BEM) tackles the difficulty of handling the intricate volume meshes and high resolution of crustal data that has put classical Finite 3D approaches in a performance crisis. The two main performance enhancements of this method: the reduction of required mesh elements from cubic to quadratic with linear size and linear-logarithmic runtime; achieve a reduction of memory and runtime requirements allowing the treatment of a new scale of geodynamic models. This approach was recently tested and applied in a series of papers by [1, 2, 3] for regional and global geodynamics, using KD trees for fast identification of near and far-field interacting elements, and MPI parallelised code on distributed memory architectures, and is now in active development for crustal dynamics. As the method is based on a free-surface, it allows easy data transfer to geological visualisation tools where only changes in boundaries and material properties are required as input parameters. In addition, easy volume mesh sampling of physical quantities enables direct integration with existing FD/FEM code.
Hanford environmental analytical methods: Methods as of March 1990. Volume 3, Appendix A2-I
Energy Technology Data Exchange (ETDEWEB)
Goheen, S.C.; McCulloch, M.; Daniel, J.L.
1993-05-01
This paper from the analytical laboratories at Hanford describes the method used to measure pH of single-shell tank core samples. Sludge or solid samples are mixed with deionized water. The pH electrode used combines both a sensor and reference electrode in one unit. The meter amplifies the input signal from the electrode and displays the pH visually.
International Nuclear Information System (INIS)
Jackson, J.F.; Bott, T.F.
1976-01-01
Analyses of the Kiwi-TNT and SNAPTRAN-2 experiments have been performed with the VENUS-II fast-reactor disassembly code. The results show that VENUS-II provides an adequate characterization of these experiments. As is the case for LMFBRs, the excursions were initially turned over by temperature feedback effects, with ultimate shutdown coming from core disassembly. The calculated fission energies agree with the experimental values to within about 50 percent for the Kiwi excursion and 10 percent for the SNAPTRAN-2 experiment. The results of the analyses are being evaluated to determine the reasons for the remaining differences. It appears that part of the difference observed in the Kiwi-TNT analysis could relate to not explicitly treating the heat-transfer from the beaded fuel (a problem not present in LMFBR calculations). Both analyses also have uncertainties associated with the new equation-of-state that had to be added to VENUS-II to allow treatment of the core materials not used in fast reactors. Finally, there are uncertainties in the temperature feedback coefficients being used. In general, the uncertainties associated with applying VENUS-II to LMFBR excursions should be even smaller than those encountered in these experimental comparisons. This is because the temperature (Doppler) coefficients and core material equations-of-state are better known, and the complications associated with heat transfer from the beaded fuel are not present
Fast radio burst search: cross spectrum vs. auto spectrum method
Liu, Lei; Zheng, Weimin; Yan, Zhen; Zhang, Juan
2018-06-01
The search for fast radio bursts (FRBs) is a hot topic in current radio astronomy studies. In this work, we carry out a single pulse search with a very long baseline interferometry (VLBI) pulsar observation data set using both auto spectrum and cross spectrum search methods. The cross spectrum method, first proposed in Liu et al., maximizes the signal power by fully utilizing the fringe phase information of the baseline cross spectrum. The auto spectrum search method is based on the popular pulsar software package PRESTO, which extracts single pulses from the auto spectrum of each station. According to our comparison, the cross spectrum method is able to enhance the signal power and therefore extract single pulses from data contaminated by high levels of radio frequency interference (RFI), which makes it possible to carry out a search for FRBs in regular VLBI observations when RFI is present.
Modern methods to improve the accuracy in fast neutron dosimetry
International Nuclear Information System (INIS)
Baers, B.; Karnani, H.; Seren, T.
1985-01-01
In order to improve the quality of fast neutron dose estimates at the reactor pressure vessel (PV) some modern methods are presented. In addition to basic principles, some error reduction procedures are also presented based on the combined use of relative measurements, direct sample taking from the pressure vessel and the use of iron and niobium as dosimeters. The influence of large systematic errors could be significantly reduced by carrying out relative measurements. This report also presents the successful use of niobium as a dosimeter by destructive treatment of PV samples. (author)
Fast nonconvex nonsmooth minimization methods for image restoration and reconstruction.
Nikolova, Mila; Ng, Michael K; Tam, Chi-Pan
2010-12-01
Nonconvex nonsmooth regularization has advantages over convex regularization for restoring images with neat edges. However, its practical interest used to be limited by the difficulty of the computational stage which requires a nonconvex nonsmooth minimization. In this paper, we deal with nonconvex nonsmooth minimization methods for image restoration and reconstruction. Our theoretical results show that the solution of the nonconvex nonsmooth minimization problem is composed of constant regions surrounded by closed contours and neat edges. The main goal of this paper is to develop fast minimization algorithms to solve the nonconvex nonsmooth minimization problem. Our experimental results show that the effectiveness and efficiency of the proposed algorithms.
Fast and accurate methods of independent component analysis: A survey
Czech Academy of Sciences Publication Activity Database
Tichavský, Petr; Koldovský, Zbyněk
2011-01-01
Roč. 47, č. 3 (2011), s. 426-438 ISSN 0023-5954 R&D Projects: GA MŠk 1M0572; GA ČR GA102/09/1278 Institutional research plan: CEZ:AV0Z10750506 Keywords : Blind source separation * artifact removal * electroencephalogram * audio signal processing Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.454, year: 2011 http://library.utia.cas.cz/separaty/2011/SI/tichavsky-fast and accurate methods of independent component analysis a survey.pdf
A Fast Adaptive Receive Antenna Selection Method in MIMO System
Directory of Open Access Journals (Sweden)
Chaowei Wang
2013-01-01
Full Text Available Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.
Multilevel Fast Multipole Method for Higher Order Discretizations
DEFF Research Database (Denmark)
Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik
2014-01-01
The multi-level fast multipole method (MLFMM) for a higher order (HO) discretization is demonstrated on high-frequency (HF) problems, illustrating for the first time how an efficient MLFMM for HO can be achieved even for very large groups. Applying several novel ideas, beneficial to both lower...... order and higher order discretizations, results from a low-memory, high-speed MLFMM implementation of a HO hierarchical discretization are shown. These results challenge the general view that the benefits of HO and HF-MLFMM cannot be combined....
Near-field hazard assessment of March 11, 2011 Japan Tsunami sources inferred from different methods
Wei, Y.; Titov, V.V.; Newman, A.; Hayes, G.; Tang, L.; Chamberlin, C.
2011-01-01
Tsunami source is the origin of the subsequent transoceanic water waves, and thus the most critical component in modern tsunami forecast methodology. Although impractical to be quantified directly, a tsunami source can be estimated by different methods based on a variety of measurements provided by deep-ocean tsunameters, seismometers, GPS, and other advanced instruments, some in real time, some in post real-time. Here we assess these different sources of the devastating March 11, 2011 Japan tsunami by model-data comparison for generation, propagation and inundation in the near field of Japan. This study provides a comparative study to further understand the advantages and shortcomings of different methods that may be potentially used in real-time warning and forecast of tsunami hazards, especially in the near field. The model study also highlights the critical role of deep-ocean tsunami measurements for high-quality tsunami forecast, and its combination with land GPS measurements may lead to better understanding of both the earthquake mechanisms and tsunami generation process. ?? 2011 MTS.
Communications overlapping in fast multipole particle dynamics methods
International Nuclear Information System (INIS)
Kurzak, Jakub; Pettitt, B. Montgomery
2005-01-01
In molecular dynamics the fast multipole method (FMM) is an attractive alternative to Ewald summation for calculating electrostatic interactions due to the operation counts. However when applied to small particle systems and taken to many processors it has a high demand for interprocessor communication. In a distributed memory environment this demand severely limits applicability of the FMM to systems with O(10 K atoms). We present an algorithm that allows for fine grained overlap of communication and computation, while not sacrificing synchronization and determinism in the equations of motion. The method avoids contention in the communication subsystem making it feasible to use the FMM for smaller systems on larger numbers of processors. Our algorithm also facilitates application of multiple time stepping techniques within the FMM. We present scaling at a reasonably high level of accuracy compared with optimized Ewald methods
A method of fast mosaic for massive UAV images
Xiang, Ren; Sun, Min; Jiang, Cheng; Liu, Lei; Zheng, Hui; Li, Xiaodong
2014-11-01
With the development of UAV technology, UAVs are used widely in multiple fields such as agriculture, forest protection, mineral exploration, natural disaster management and surveillances of public security events. In contrast of traditional manned aerial remote sensing platforms, UAVs are cheaper and more flexible to use. So users can obtain massive image data with UAVs, but this requires a lot of time to process the image data, for example, Pix4UAV need approximately 10 hours to process 1000 images in a high performance PC. But disaster management and many other fields require quick respond which is hard to realize with massive image data. Aiming at improving the disadvantage of high time consumption and manual interaction, in this article a solution of fast UAV image stitching is raised. GPS and POS data are used to pre-process the original images from UAV, belts and relation between belts and images are recognized automatically by the program, in the same time useless images are picked out. This can boost the progress of finding match points between images. Levenberg-Marquard algorithm is improved so that parallel computing can be applied to shorten the time of global optimization notably. Besides traditional mosaic result, it can also generate superoverlay result for Google Earth, which can provide a fast and easy way to show the result data. In order to verify the feasibility of this method, a fast mosaic system of massive UAV images is developed, which is fully automated and no manual interaction is needed after original images and GPS data are provided. A test using 800 images of Kelan River in Xinjiang Province shows that this system can reduce 35%-50% time consumption in contrast of traditional methods, and increases respond speed of UAV image processing rapidly.
Fast methods for spatially correlated multilevel functional data
Staicu, A.-M.
2010-01-19
We propose a new methodological framework for the analysis of hierarchical functional data when the functions at the lowest level of the hierarchy are correlated. For small data sets, our methodology leads to a computational algorithm that is orders of magnitude more efficient than its closest competitor (seconds versus hours). For large data sets, our algorithm remains fast and has no current competitors. Thus, in contrast to published methods, we can now conduct routine simulations, leave-one-out analyses, and nonparametric bootstrap sampling. Our methods are inspired by and applied to data obtained from a state-of-the-art colon carcinogenesis scientific experiment. However, our models are general and will be relevant to many new data sets where the object of inference are functions or images that remain dependent even after conditioning on the subject on which they are measured. Supplementary materials are available at Biostatistics online.
A Fast Kurtogram Demodulation Method in Rolling Bearing Fault Diagnosis
Directory of Open Access Journals (Sweden)
Li Li
2016-01-01
Full Text Available Targeting at the problem of finding the best demodulation band when applying envelope analysis in rolling bearing fault diagnosis, this paper proposes a novel Fast Kurtogram Demodulation Method (FKDM to solve the problem. FKDM is established based on the theory of spectrum kurtosis and the short-time Fourier Transform. It determines the best demodulation band firstly, which is also known as the central frequency and frequency resolution. Then, the fault signals can be demodulated in the obtained frequency band by using envelope demodulation algorithm. The FKDM method ensures the fault diagnosis correction by solving the problem of demodulation band selection. Applied FKDM in rolling bearing fault diagnosis and compared with conventional envelope analysis, the results demonstrate FKDM can achieve a better performance.
Treatment of fast reactor liquid waste- electrochemical method
International Nuclear Information System (INIS)
Mahato, Swapan Kumar; Sudha, R.; Anthonysamy, S.; Muralidaran, P.
2015-01-01
During the operation of fast reactors, components get wetted by sodium. The sodium wetted primary components such as pumps and intermediate heat exchangers (IHX) in fast reactors are cleaned free of sodium followed by suitable chemical decontamination process before taking them for maintenance or for disposal. This helps in reduction of radiation dose to the operating personnel. Sodium cleaning and decontamination generates large volumes of liquid effluent. The activity in the liquid effluent during sodium cleaning/decontamination is due to 22 Na, 54 Mn, 58 Co, 60 Co, 59 Fe, 137 Cs and 134 Cs. It is required to chemically treat the effluent to reduce the activity levels prior to storage in tanks and transportation to the waste management facility for final disposal. Conventionally the ion exchange method is used for removal of radionuclides which produces large quantities of secondary waste. A method which is suitable both for removal of radionuclides present in low concentration and that avoids generation of large quantities of secondary waste is required. Hence an electrochemical method for metal ion removal is attempted in this work which produces little or no secondary waste. Electrochemical method towards removal of manganese ions was finalized earlier using reticulated vitreous carbon (RVC) from simulated decontamination solution containing a mixture of sulphuric and phosphoric acids. In continuation of the experiments for the removal of cesium ions from simulated cleaning solution which has an alkaline pH, a thin film of nickel hexacyanoferrate (NiHCF) was deposited electrochemically on the surface of RVC. Hexacyanoferrates are known for selectively binding cesium. This NiHCF coated RVC was used for electrodeposition of Cs ions. NiHCF coated and Cs deposited RVC was characterized using SEM/EDX analysis. EDX analysis confirms the presence of Cs on NiHCF coated RVC. (author)
The use of the spectral method within the fast adaptive composite grid method
Energy Technology Data Exchange (ETDEWEB)
McKay, S.M.
1994-12-31
The use of efficient algorithms for the solution of partial differential equations has been sought for many years. The fast adaptive composite grid (FAC) method combines an efficient algorithm with high accuracy to obtain low cost solutions to partial differential equations. The FAC method achieves fast solution by combining solutions on different grids with varying discretizations and using multigrid like techniques to find fast solution. Recently, the continuous FAC (CFAC) method has been developed which utilizes an analytic solution within a subdomain to iterate to a solution of the problem. This has been shown to achieve excellent results when the analytic solution can be found. The CFAC method will be extended to allow solvers which construct a function for the solution, e.g., spectral and finite element methods. In this discussion, the spectral methods will be used to provide a fast, accurate solution to the partial differential equation. As spectral methods are more accurate than finite difference methods, the ensuing accuracy from this hybrid method outside of the subdomain will be investigated.
Apparatus and method for detecting contraband using fast neutron activation
International Nuclear Information System (INIS)
Gozani, T.; Sawa, Z.P.; Shea, P.M.
1992-01-01
This patent describes a method of detecting contraband within an object under investigation. It comprises: generating a beam of case neutrons; irradiating the object with the beam of fast neutrons, the fast neutrons interacting with atomic nuclei of the elements contained within the object to produce a gamma-ray spectrum having spectral lines characteristic of the elements contained within the object; measuring the spectral lines of the gamma-ray spectrum using a multiplicity of gamma-ray detectors judiciously positioned around the object; detecting the number of neutrons that pass through the object without interacting substantially with atomic nuclei within the object; determining the spatial and density distributions of the atomic nuclei of the elements contained within the object from the measured gamma-ray spectrum obtained from the multiplicity of gamma-ray detectors and the number of neutrons that pass through the object; comparing the measured spatial and density distributions of the atomic nuclei of the elements within the object with known spatial and density distributions of atomic nuclei for elements characteristic of contraband; and determining that contraband is present within the object when the comparison indicates a substantial match
A fast summation method for oscillatory lattice sums
Denlinger, Ryan; Gimbutas, Zydrunas; Greengard, Leslie; Rokhlin, Vladimir
2017-02-01
We present a fast summation method for lattice sums of the type which arise when solving wave scattering problems with periodic boundary conditions. While there are a variety of effective algorithms in the literature for such calculations, the approach presented here is new and leads to a rigorous analysis of Wood's anomalies. These arise when illuminating a grating at specific combinations of the angle of incidence and the frequency of the wave, for which the lattice sums diverge. They were discovered by Wood in 1902 as singularities in the spectral response. The primary tools in our approach are the Euler-Maclaurin formula and a steepest descent argument. The resulting algorithm has super-algebraic convergence and requires only milliseconds of CPU time.
Fast calculation method for computer-generated cylindrical holograms.
Yamaguchi, Takeshi; Fujii, Tomohiko; Yoshikawa, Hiroshi
2008-07-01
Since a general flat hologram has a limited viewable area, we usually cannot see the other side of a reconstructed object. There are some holograms that can solve this problem. A cylindrical hologram is well known to be viewable in 360 deg. Most cylindrical holograms are optical holograms, but there are few reports of computer-generated cylindrical holograms. The lack of computer-generated cylindrical holograms is because the spatial resolution of output devices is not great enough; therefore, we have to make a large hologram or use a small object to fulfill the sampling theorem. In addition, in calculating the large fringe, the calculation amount increases in proportion to the hologram size. Therefore, we propose what we believe to be a new calculation method for fast calculation. Then, we print these fringes with our prototype fringe printer. As a result, we obtain a good reconstructed image from a computer-generated cylindrical hologram.
A Fast Radio Burst Search Method for VLBI Observation
Liu, Lei; Tong, Fengxian; Zheng, Weimin; Zhang, Juan; Tong, Li
2018-02-01
We introduce the cross-spectrum-based fast radio burst (FRB) search method for Very Long Baseline Interferometer (VLBI) observation. This method optimizes the fringe fitting scheme in geodetic VLBI data post-processing, which fully utilizes the cross-spectrum fringe phase information and therefore maximizes the power of single-pulse signals. Working with cross-spectrum greatly reduces the effect of radio frequency interference compared with using auto-power spectrum. Single-pulse detection confidence increases by cross-identifying detections from multiple baselines. By combining the power of multiple baselines, we may improve the detection sensitivity. Our method is similar to that of coherent beam forming, but without the computational expense to form a great number of beams to cover the whole field of view of our telescopes. The data processing pipeline designed for this method is easy to implement and parallelize, which can be deployed in various kinds of VLBI observations. In particular, we point out that VGOS observations are very suitable for FRB search.
DEFF Research Database (Denmark)
Zuidmeer-Jongejan, Laurian; Fernandez-Rivas, Montserrat; Poulsen, Lars K.
2012-01-01
ABSTRACT: The FAST project (Food Allergy Specific Immunotherapy) aims at the development of safe and effective treatment of food allergies, targeting prevalent, persistent and severe allergy to fish and peach. Classical allergen-specific immunotherapy (SIT), using subcutaneous injections with aqu...
Fast electronic structure methods for strongly correlated molecular systems
International Nuclear Information System (INIS)
Head-Gordon, Martin; Beran, Gregory J O; Sodt, Alex; Jung, Yousung
2005-01-01
A short review is given of newly developed fast electronic structure methods that are designed to treat molecular systems with strong electron correlations, such as diradicaloid molecules, for which standard electronic structure methods such as density functional theory are inadequate. These new local correlation methods are based on coupled cluster theory within a perfect pairing active space, containing either a linear or quadratic number of pair correlation amplitudes, to yield the perfect pairing (PP) and imperfect pairing (IP) models. This reduces the scaling of the coupled cluster iterations to no worse than cubic, relative to the sixth power dependence of the usual (untruncated) coupled cluster doubles model. A second order perturbation correction, PP(2), to treat the neglected (weaker) correlations is formulated for the PP model. To ensure minimal prefactors, in addition to favorable size-scaling, highly efficient implementations of PP, IP and PP(2) have been completed, using auxiliary basis expansions. This yields speedups of almost an order of magnitude over the best alternatives using 4-center 2-electron integrals. A short discussion of the scope of accessible chemical applications is given
Neutron spectrum determination by activation method in fast neutron fields at the RB reactor
International Nuclear Information System (INIS)
Sokcic-Kostic, M.; Pesic, M.; Antic, D.
1994-01-01
The fast neutron fields of the RB reactor are presented in this paper. The activation method for spectrum determination is described and explained. The obtained results for intermediate and fast spectrum are given and discussed. (author)
Neutron spectrum determination by activation method in fast neutron fields at the RB reactors
International Nuclear Information System (INIS)
Sokcic-Kostic, M.S.; Pesic, M.P.; Antic, D.P.
1994-01-01
The fast neutron fields of the RB reactor are presented in this paper. The activation method for spectrum determination is described and explained. The obtained results for intermediate and fast spectrum are given and discussed. (authors). 7 refs., 3 tabs
DEFF Research Database (Denmark)
Li, Helong; Beczkowski, Szymon; Munk-Nielsen, Stig
2015-01-01
This paper proposes a novel current measurement method with Silicon Steel Current Transformer (SSCT) for the characterization of fast switching power semiconductors. First, the existing current sensors for characterization of fast switching power semiconductors are experimentally evaluated...
Energy Technology Data Exchange (ETDEWEB)
Goheen, S.C.; McCulloch, M.; Daniel, J.L.
1993-05-01
Techniques in use at the Hanford Reservation as of March, 1990 for the analysis of liquids, organic wastes, soils, and sediments, are described. Limitations and applications of the techniques are included.
Modeling the Performance of Fast Mulipole Method on HPC platforms
Ibeid, Huda
2012-04-06
The current trend in high performance computing is pushing towards exascale computing. To achieve this exascale performance, future systems will have between 100 million and 1 billion cores assuming gigahertz cores. Currently, there are many efforts studying the hardware and software bottlenecks for building an exascale system. It is important to understand and meet these bottlenecks in order to attain 10 PFLOPS performance. On applications side, there is an urgent need to model application performance and to understand what changes need to be made to ensure continued scalability at this scale. Fast multipole methods (FMM) were originally developed for accelerating N-body problems for particle based methods. Nowadays, FMM is more than an N-body solver, recent trends in HPC have been to use FMMs in unconventional application areas. FMM is likely to be a main player in exascale due to its hierarchical nature and the techniques used to access the data via a tree structure which allow many operations to happen simultaneously at each level of the hierarchy. In this thesis , we discuss the challenges for FMM on current parallel computers and future exasclae architecture. Furthermore, we develop a novel performance model for FMM. Our ultimate aim of this thesis is to ensure the scalability of FMM on the future exascale machines.
A fast iterative method for computing particle beams penetrating matter
International Nuclear Information System (INIS)
Boergers, C.
1997-01-01
Beams of microscopic particles penetrating matter are important in several fields. The application motivating our parameter choices in this paper is electron beam cancer therapy. Mathematically, a steady particle beam penetrating matter, or a configuration of several such beams, is modeled by a boundary value problem for a Boltzmann equation. Grid-based discretization of this problem leads to a system of algebraic equations. This system is typically very large because of the large number of independent variables in the Boltzmann equation (six if time independence is the only dimension-reducing assumption). If grid-based methods are to be practical at all, it is therefore necessary to develop fast solvers for the discretized problems. This is the subject of the present paper. For two-dimensional, mono-energetic, linear particle beam problems, we describe an iterative domain decomposition algorithm based on overlapping decompositions of the set of particle directions and computationally demonstrate its rapid, grid independent convergence. There appears to be no fundamental obstacle to generalizing the method to three-dimensional, energy dependent problems. 34 refs., 15 figs., 6 tabs
Fast and sensitive method for detecting volatile species in liquids
Trimarco, Daniel B.; Pedersen, Thomas; Hansen, Ole; Chorkendorff, Ib; Vesborg, Peter C. K.
2015-07-01
This paper presents a novel apparatus for extracting volatile species from liquids using a "sniffer-chip." By ultrafast transfer of the volatile species through a perforated and hydrophobic membrane into an inert carrier gas stream, the sniffer-chip is able to transport the species directly to a mass spectrometer through a narrow capillary without the use of differential pumping. This method inherits features from differential electrochemical mass spectrometry (DEMS) and membrane inlet mass spectrometry (MIMS), but brings the best of both worlds, i.e., the fast time-response of a DEMS system and the high sensitivity of a MIMS system. In this paper, the concept of the sniffer-chip is thoroughly explained and it is shown how it can be used to quantify hydrogen and oxygen evolution on a polycrystalline platinum thin film in situ at absolute faradaic currents down to ˜30 nA. To benchmark the capabilities of this method, a CO-stripping experiment is performed on a polycrystalline platinum thin film, illustrating how the sniffer-chip system is capable of making a quantitative in situ measurement of <1 % of a monolayer of surface adsorbed CO being electrochemically stripped off an electrode at a potential scan-rate of 50 mV s-1.
A Fast Optimization Method for General Binary Code Learning.
Shen, Fumin; Zhou, Xiang; Yang, Yang; Song, Jingkuan; Shen, Heng; Tao, Dacheng
2016-09-22
Hashing or binary code learning has been recognized to accomplish efficient near neighbor search, and has thus attracted broad interests in recent retrieval, vision and learning studies. One main challenge of learning to hash arises from the involvement of discrete variables in binary code optimization. While the widely-used continuous relaxation may achieve high learning efficiency, the pursued codes are typically less effective due to accumulated quantization error. In this work, we propose a novel binary code optimization method, dubbed Discrete Proximal Linearized Minimization (DPLM), which directly handles the discrete constraints during the learning process. Specifically, the discrete (thus nonsmooth nonconvex) problem is reformulated as minimizing the sum of a smooth loss term with a nonsmooth indicator function. The obtained problem is then efficiently solved by an iterative procedure with each iteration admitting an analytical discrete solution, which is thus shown to converge very fast. In addition, the proposed method supports a large family of empirical loss functions, which is particularly instantiated in this work by both a supervised and an unsupervised hashing losses, together with the bits uncorrelation and balance constraints. In particular, the proposed DPLM with a supervised `2 loss encodes the whole NUS-WIDE database into 64-bit binary codes within 10 seconds on a standard desktop computer. The proposed approach is extensively evaluated on several large-scale datasets and the generated binary codes are shown to achieve very promising results on both retrieval and classification tasks.
A proposed method for fast determination of plasma parameters
International Nuclear Information System (INIS)
Braams, B.J.; Lackner, K.
1984-09-01
The method of function parametrization, developed and applied by H. Wind for fast data evaluation in high energy physics, is presented in the context of controlled fusion research. This method relies on statistical analysis of a data base of simulated experiments in order to obtain a functional representation for the intrinsic physical parameters of a system in terms of the values of the measurements. Some variations on Wind's original procedure are suggested. A specific application for tokamak experiments would be the determination of certain global parameters of the plasma, characterizing the current profile, shape of the cross-section, plasma pressure, and the internal inductance. The relevant measurements for this application include values of the poloidal field and flux external to the plasma, and a diamagnetic measurement. These may be combined with other diagnostics, such as electron-cyclotron emission and laser interferometry, in order to obtain also density and temperature profiles. There appears to be a capability for on-line determination of basic physical parameters, in a millisecond timescale on a minicomputer instead of in seconds on a large mainframe. (orig.)
Hardware architecture design of a fast global motion estimation method
Liang, Chaobing; Sang, Hongshi; Shen, Xubang
2015-12-01
VLSI implementation of gradient-based global motion estimation (GME) faces two main challenges: irregular data access and high off-chip memory bandwidth requirement. We previously proposed a fast GME method that reduces computational complexity by choosing certain number of small patches containing corners and using them in a gradient-based framework. A hardware architecture is designed to implement this method and further reduce off-chip memory bandwidth requirement. On-chip memories are used to store coordinates of the corners and template patches, while the Gaussian pyramids of both the template and reference frame are stored in off-chip SDRAMs. By performing geometric transform only on the coordinates of the center pixel of a 3-by-3 patch in the template image, a 5-by-5 area containing the warped 3-by-3 patch in the reference image is extracted from the SDRAMs by burst read. Patched-based and burst mode data access helps to keep the off-chip memory bandwidth requirement at the minimum. Although patch size varies at different pyramid level, all patches are processed in term of 3x3 patches, so the utilization of the patch-processing circuit reaches 100%. FPGA implementation results show that the design utilizes 24,080 bits on-chip memory and for a sequence with resolution of 352x288 and frequency of 60Hz, the off-chip bandwidth requirement is only 3.96Mbyte/s, compared with 243.84Mbyte/s of the original gradient-based GME method. This design can be used in applications like video codec, video stabilization, and super-resolution, where real-time GME is a necessity and minimum memory bandwidth requirement is appreciated.
A New Fast Vertical Method for Mining Frequent Patterns
Directory of Open Access Journals (Sweden)
Zhihong Deng
2010-12-01
Full Text Available Vertical mining methods are very effective for mining frequent patterns and usually outperform horizontal mining methods. However, the vertical methods become ineffective since the intersection time starts to be costly when the cardinality of tidset (tid-list or diffset is very large or there are a very large number of transactions. In this paper, we propose a novel vertical algorithm called PPV for fast frequent pattern discovery. PPV works based on a data structure called Node-lists, which is obtained from a coding prefix-tree called PPC-tree. The efficiency of PPV is achieved with three techniques. First, the Node-list is much more compact compared with previous proposed vertical structure (such as tid-lists or diffsets since transactions with common prefixes share the same nodes of the PPC-tree. Second, the counting of support is transformed into the intersection of Node-lists and the complexity of intersecting two Node-lists can be reduced to O(m+n by an efficient strategy, where m and n are the cardinalities of the two Node-lists respectively. Third, the ancestor-descendant relationship of two nodes, which is the basic step of intersecting Node-lists, can be very efficiently verified by Pre-Post codes of nodes. We experimentally compare our algorithm with FP-growth, and two prominent vertical algorithms (Eclat and dEclat on a number of databases. The experimental results show that PPV is an efficient algorithm that outperforms FP-growth, Eclat, and dEclat.
A method for fast automated microscope image stitching.
Yang, Fan; Deng, Zhen-Sheng; Fan, Qiu-Hong
2013-05-01
Image stitching is an important technology to produce a panorama or larger image by combining several images with overlapped areas. In many biomedical researches, image stitching is highly desirable to acquire a panoramic image which represents large areas of certain structures or whole sections, while retaining microscopic resolution. In this study, we develop a fast normal light microscope image stitching algorithm based on feature extraction. At first, an algorithm of scale-space reconstruction of speeded-up robust features (SURF) was proposed to extract features from the images to be stitched with a short time and higher repeatability. Then, the histogram equalization (HE) method was employed to preprocess the images to enhance their contrast for extracting more features. Thirdly, the rough overlapping zones of the images preprocessed were calculated by phase correlation, and the improved SURF was used to extract the image features in the rough overlapping areas. Fourthly, the features were corresponded by matching algorithm and the transformation parameters were estimated, then the images were blended seamlessly. Finally, this procedure was applied to stitch normal light microscope images to verify its validity. Our experimental results demonstrate that the improved SURF algorithm is very robust to viewpoint, illumination, blur, rotation and zoom of the images and our method is able to stitch microscope images automatically with high precision and high speed. Also, the method proposed in this paper is applicable to registration and stitching of common images as well as stitching the microscope images in the field of virtual microscope for the purpose of observing, exchanging, saving, and establishing a database of microscope images. Copyright © 2013 Elsevier Ltd. All rights reserved.
Data-driven execution of fast multipole methods
Ltaief, Hatem
2013-09-17
Fast multipole methods (FMMs) have O (N) complexity, are compute bound, and require very little synchronization, which makes them a favorable algorithm on next-generation supercomputers. Their most common application is to accelerate N-body problems, but they can also be used to solve boundary integral equations. When the particle distribution is irregular and the tree structure is adaptive, load balancing becomes a non-trivial question. A common strategy for load balancing FMMs is to use the work load from the previous step as weights to statically repartition the next step. The authors discuss in the paper another approach based on data-driven execution to efficiently tackle this challenging load balancing problem. The core idea consists of breaking the most time-consuming stages of the FMMs into smaller tasks. The algorithm can then be represented as a directed acyclic graph where nodes represent tasks and edges represent dependencies among them. The execution of the algorithm is performed by asynchronously scheduling the tasks using the queueing and runtime for kernels runtime environment, in a way such that data dependencies are not violated for numerical correctness purposes. This asynchronous scheduling results in an out-of-order execution. The performance results of the data-driven FMM execution outperform the previous strategy and show linear speedup on a quad-socket quad-core Intel Xeon system.Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
A task parallel implementation of fast multipole methods
Taura, Kenjiro
2012-11-01
This paper describes a task parallel implementation of ExaFMM, an open source implementation of fast multipole methods (FMM), using a lightweight task parallel library MassiveThreads. Although there have been many attempts on parallelizing FMM, experiences have almost exclusively been limited to formulation based on flat homogeneous parallel loops. FMM in fact contains operations that cannot be readily expressed in such conventional but restrictive models. We show that task parallelism, or parallel recursions in particular, allows us to parallelize all operations of FMM naturally and scalably. Moreover it allows us to parallelize a \\'\\'mutual interaction\\'\\' for force/potential evaluation, which is roughly twice as efficient as a more conventional, unidirectional force/potential evaluation. The net result is an open source FMM that is clearly among the fastest single node implementations, including those on GPUs; with a million particles on a 32 cores Sandy Bridge 2.20GHz node, it completes a single time step including tree construction and force/potential evaluation in 65 milliseconds. The study clearly showcases both programmability and performance benefits of flexible parallel constructs over more monolithic parallel loops. © 2012 IEEE.
Method and device for fire extinction of fast breeder reactors
International Nuclear Information System (INIS)
Yokota, Norikatsu; Shimoyashiki, Shigehiro; Hikichi, Takayoshi; Sato, Yoshihiko.
1986-01-01
Purpose: To effectively restrain fires with coolant in liquid-metal fast breeder reactors. Method: The core material of fire-extinguishing agent is coated with a non-combustible material and capsulated to prevent moisture absorption and at the same time the capsule thus made is coated with a suitable material to restrain a fire with a coolant. A desirable coating material to be used is a material which is little reactive to sodium; for example such a low-melting point metal as Pb or Sn, or paraffin, or sodium-silicate should be used. For the core material, Na 2 CO 3 , NaCl sand are recommendable materials. The core material thus made will never absorb moisture during long-time storage and has no hazard to promote a fire likely to be caused by moisture absorption. Furthermore, the coating material and the core material act to each other, restraining a sodium fire. The fire-extinguishing agent, being granular and capsulated, is easy to transport, thereby reducing a cost required for disposition. (Kamimura, M.)
Analysis methods for fast impurity ion dynamics data
International Nuclear Information System (INIS)
Den Hartog, D.J.; Almagri, A.F.; Prager, S.C.; Fonck, R.J.
1994-08-01
A high resolution spectrometer has been developed and used on the MST reversed-field pinch (RFP) to measure passively impurity ion temperatures and flow velocities with 10 μs temporal resolution. Such measurements of MHD-scale fluctuations are particularly relevant in the RFP because the flow velocity fluctuation induced transport of current (the ''MHD dynamo'') may produce the magnetic field reversal characteristic of an RFP. This instrument will also be used to measure rapid changes in the equilibrium flow velocity, such as occur during locking and H-mode transition. The precision of measurements made to date is <0.6 km/s. The authors are developing accurate analysis techniques appropriate to the reduction of this fast ion dynamics data. Moment analysis and curve-fitting routines have been evaluated for noise sensitivity and robustness. Also presented is an analysis method which correctly separates the flux-surface average of the correlated fluctuations in u and B from the fluctuations due to rigid shifts of the plasma column
Nuclear data and multigroup methods in fast reactor calculations
International Nuclear Information System (INIS)
Gur, Y.
1975-03-01
The work deals with fast reactor multigroup calculations, and the efficient treatment of basic nuclear data, which serves as raw material for the calculations. Its purpose is twofold: to build a computer code system that handles a large, detailed library of basic neutron cross section data, (such as ENDF/B-III) and yields a compact set of multigroup cross sections for reactor calculations; to use the code system for comparative analysis of different libraries, in order to discover basic uncertainties that still exist in the measurement of neutron cross sections, and to determine their influence upon uncertainties in nuclear calculations. A program named NANICK which was written in two versions is presented. The first handles the American basic data library, ENDF/B-III, while the second handles the German basic data library, KEDAK. The mathematical algorithm is identical in both versions, and only the file management is different. This program calculates infinitely diluted multigroup cross sections and scattering matrices. It is complemented by the program NASIF that calculates shielding factors from resonance parameters. Different versions of NASIF were written to handle ENDF/B-III or KEDAK. New methods for evaluating in reactor calculations the long term behavior of the neutron flux as well as its fine structure are described and an efficient calculation of the shielding factors from resonance parameters is offered. (B.G.)
Methods for performing fast discrete curvelet transforms of data
Candes, Emmanuel; Donoho, David; Demanet, Laurent
2010-11-23
Fast digital implementations of the second generation curvelet transform for use in data processing are disclosed. One such digital transformation is based on unequally-spaced fast Fourier transforms (USFFT) while another is based on the wrapping of specially selected Fourier samples. Both digital transformations return a table of digital curvelet coefficients indexed by a scale parameter, an orientation parameter, and a spatial location parameter. Both implementations are fast in the sense that they run in about O(n.sup.2 log n) flops for n by n Cartesian arrays or about O(N log N) flops for Cartesian arrays of size N=n.sup.3; in addition, they are also invertible, with rapid inversion algorithms of about the same complexity.
Development of a fast voltage control method for electrostatic accelerators
International Nuclear Information System (INIS)
Lobanov, Nikolai R.; Linardakis, Peter; Tsifakis, Dimitrios
2014-01-01
The concept of a novel fast voltage control loop for tandem electrostatic accelerators is described. This control loop utilises high-frequency components of the ion beam current intercepted by the image slits to generate a correction voltage that is applied to the first few gaps of the low- and high-energy acceleration tubes adjoining the high voltage terminal. New techniques for the direct measurement of the transfer function of an ultra-high impedance structure, such as an electrostatic accelerator, have been developed. For the first time, the transfer function for the fast feedback loop has been measured directly. Slow voltage variations are stabilised with common corona control loop and the relationship between transfer functions for the slow and new fast control loops required for optimum operation is discussed. The main source of terminal voltage instabilities, which are due to variation of the charging current caused by mechanical oscillations of charging chains, has been analysed
Transparent fast neutron shielding material and shielding method
International Nuclear Information System (INIS)
Nashimoto, Tetsuji; Katase, Haruhisa.
1993-01-01
Polyisobutylene having a viscosity average molecular weight of 20,000 to 80,000 and a hydrogen atom density of greater than 7.0 x 10 22 /cm 3 is used as a fast neutron shielding material. The shielding material is excellent in the shielding performance against fast neutrons, and there is no worry of leakage even when holes should be formed to a vessel. Further, it is excellent in fabricability, relatively safe even upon occurrence of fire and, in addition, it is transparent to enable to observe contents easily. (T.M.)
Fast Computation and Assessment Methods in Power System Analysis
Nagata, Masaki
Power system analysis is essential for efficient and reliable power system operation and control. Recently, online security assessment system has become of importance, as more efficient use of power networks is eagerly required. In this article, fast power system analysis techniques such as contingency screening, parallel processing and intelligent systems application are briefly surveyed from the view point of their application to online dynamic security assessment.
He, An; Gong, Jiaming; Shikazono, Naoki
2018-05-01
In the present study, a model is introduced to correlate the electrochemical performance of solid oxide fuel cell (SOFC) with the 3D microstructure reconstructed by focused ion beam scanning electron microscopy (FIB-SEM) in which the solid surface is modeled by the marching cubes (MC) method. Lattice Boltzmann method (LBM) is used to solve the governing equations. In order to maintain the geometries reconstructed by the MC method, local effective diffusivities and conductivities computed based on the MC geometries are applied in each grid, and partial bounce-back scheme is applied according to the boundary predicted by the MC method. From the tortuosity factor and overpotential calculation results, it is concluded that the MC geometry drastically improves the computational accuracy by giving more precise topology information.
Neutronics methods for transient and safety analysis of fast reactors
Energy Technology Data Exchange (ETDEWEB)
Marchetti, Marco
2017-07-01
Modeling the evolution of possible or postulated accidents in nuclear reactors is fundamental in designing safe systems. For the next generation of reactors, in particular fast reactors, fuel movement during an accident can, in principle, drive an energetic event. Such is the issue of recriticality. The thermal energy produced during these events will, possibly, be converted into mechanical energy by some mechanisms. For example, the nuclear heat deposited in the fuel could cause fuel vaporization and its subsequent expansion. This movement would accelerate the surrounding sodium: part of the initial energy in the fuel is thus converted into sodium kinetic energy. This mechanical energy will finally be absorbed, in some way or another, by the reactor vessel. Providing an accurate estimate for the maximum mechanical work that any accidental sequence can do onto the reactor vessel is an essential step in designing a reactor containment that would withstand any load generated by any accident. That would assure accident containment, without consequences for the general public. Fast reactor accident modeling is a complicated task. The outcome of an accident is determined by different physical phenomena, all acting at almost the same time. Safety analysts must track all these different phenomena. Multi-physics codes have been developed for this task. They must contain accurate models for fluid-dynamics, neutronics, and structures. This work has to do with neutronics modeling of such accidents. Past and recent analyses have been limited to the approximate description of the neutronic field, for example by using a rough description of the energy and/or of the angular dependence of the neutron flux. In this work, different neutronic solvers are selected and coupled into a general multi-physics code for fast reactor accident analysis. Performances of each of them is then assessed. Some emphasis has been put also in assessing the speed of these solvers for determining the
A fast collocation method for a variable-coefficient nonlocal diffusion model
Wang, Che; Wang, Hong
2017-02-01
We develop a fast collocation scheme for a variable-coefficient nonlocal diffusion model, for which a numerical discretization would yield a dense stiffness matrix. The development of the fast method is achieved by carefully handling the variable coefficients appearing inside the singular integral operator and exploiting the structure of the dense stiffness matrix. The resulting fast method reduces the computational work from O (N3) required by a commonly used direct solver to O (Nlog N) per iteration and the memory requirement from O (N2) to O (N). Furthermore, the fast method reduces the computational work of assembling the stiffness matrix from O (N2) to O (N). Numerical results are presented to show the utility of the fast method.
Experimental Methods Related to Coupled Fast-Thermal Systems at the RB Reactor
International Nuclear Information System (INIS)
Pesic, M.
2002-01-01
In addition to the review of RB reactor characteristics this presentation is focused on the coupled fast-thermal systems achieved at the reactor. The following experimental methods are presented: neutron spectra measurements; steady state experiments and kinetic measurements ( β eff ) related to the coupled fast-thermal cores
Preliminary experiment of fast neutron imaging with direct-film method
International Nuclear Information System (INIS)
Pei Yuyang; Tang Guoyou; Guo Zhiyu; Zhang Guohui
2005-01-01
A preliminary experiment is conducted with direct-film method under the condition that fast neutron is generated by the reaction of 9 Be(d, n) on the Beijing University 4.5 MV Van de Graaff, whose energy is lower than 7 MeV. Basic characteristics of direct-film neutron radiography system are investigated with the help of samples in different materials, different thickness and holes of different diameter. The fast neutron converter, which is vital for fast neutron imaging, is produced with the materials made in China. The result indicates that fast neutron converter can meet the requirement of fast neutron imaging; further research of fast neutron imaging can be conducted on the accelerator and neutron-generator in China. (authors)
Fast LCMV-based Methods for Fundamental Frequency Estimation
DEFF Research Database (Denmark)
Jensen, Jesper Rindom; Glentis, George-Othon; Christensen, Mads Græsbøll
2013-01-01
peaks and require matrix inversions for each point in the search grid. In this paper, we therefore consider fast implementations of LCMV-based fundamental frequency estimators, exploiting the estimators' inherently low displacement rank of the used Toeplitz-like data covariance matrices, using...... with several orders of magnitude, but, as we show, further computational savings can be obtained by the adoption of an approximative IAA-based data covariance matrix estimator, reminiscent of the recently proposed Quasi-Newton IAA technique. Furthermore, it is shown how the considered pitch estimators can...... as such either the classic time domain averaging covariance matrix estimator, or, if aiming for an increased spectral resolution, the covariance matrix resulting from the application of the recent iterative adaptive approach (IAA). The proposed exact implementations reduce the required computational complexity...
Comparison study on cell calculation method of fast reactor
International Nuclear Information System (INIS)
Chiba, Gou
2002-10-01
Effective cross sections obtained by cell calculations are used in core calculations in current deterministic methods. Therefore, it is important to calculate the effective cross sections accurately and several methods have been proposed. In this study, some of the methods are compared to each other using a continuous energy Monte Carlo method as a reference. The result shows that the table look-up method used in Japan Nuclear Cycle Development Institute (JNC) sometimes has a difference over 10% in effective microscopic cross sections and be inferior to the sub-group method. The problem was overcome by introducing a new nuclear constant system developed in JNC, in which the ultra free energy group library is used. The system can also deal with resonance interaction effects between nuclides which are not able to be considered by other methods. In addition, a new method was proposed to calculate effective cross section accurately for power reactor fuel subassembly where the new nuclear constant system cannot be applied. This method uses the sub-group method and the ultra fine energy group collision probability method. The microscopic effective cross sections obtained by this method agree with the reference values within 5% difference. (author)
Nondestructive, fast methods for burn-up study
International Nuclear Information System (INIS)
Schaechter, L.; Hacman, D.; Mot, O.
1977-01-01
Nondestructive methods, based on high resolution-spectrometry successfully applied at Institute for Atomic Physics are presented. These methods are preferred to destructive chemical methods; the latter being costly and lengthy and not suitable for statistical prediction of nuclear fuel behaviour. The following methods are developed: methods for determining the burn up of fuel elements and fuel assemblies; a method for determining the U 235 and Pu 239 contributions to the burn up and a code written in FORTRAN IV for numerical calculation of Pu 239 fission vs. burn up; a high precision method for burnup determination by adding burnable poison; a method for prediction of specific power distribution in the fuel elements of a research or power reactors; a method for determining the power output of the fuel element in an operating power reactor; a method for determining the content of Pu 239 of the fuel element irradiated in a reactor. The results which were obtained by these methods improved the fuel management at the VVR-S reactor at Institute for Atomic Physics, Bucharest and may be applied to other reactor types [fr
Laboratory testing of geomembrane for waste containment EPA Method 9090, March 1995. Final report
Energy Technology Data Exchange (ETDEWEB)
Whitlock, R.W. [Westinghouse Hanford Co., Richland, WA (United States)
1995-05-15
This report describes the work performed by TRI/Environmental, Inc. (TRI) to determine the chemical compatibility of one geomembrane and one seamed geomembrane with four synthetically generated leachates. The objective was to determine the resistance of the geomembrane to changes caused by exposure to the leachates. Changes in physical and mechanical properties were measured after exposure to the leachates at 23 C and 50 C for 30, 60, 90 and 120 days. Exposures were performed in accordance with the exposure regimen specified in US Environmental Protection Agency (EPA) Method 9090A. Methods, results and discussion are provided. Test results are also provided in the Tables of Results which accompany this report.
Method of advancing research and development of fast breeder reactors
International Nuclear Information System (INIS)
1988-01-01
In the long term plan of atomic energy development and utilization, fast breeder reactors are to be developed as the main of the future nuclear power generation in Japan, and when their development is advanced, it has been decided to positively aim at building up the plutonium utilization system using FBRs superior to the uranium utilization system using LWRs. Also it has been decided that the development of FBRs requires to exert incessant efforts for a considerable long period under the proper cooperation system of government and people, and as for its concrete development, hereafter the deliberation is to be carried out in succession by the expert subcommittee on FBR development projects of the Atomic Energy Commission. The subcommittee was founded in May, 1986, to deliberate on the long term promotion measures for FBR development, the measures for promoting the research and development, the examination of the basic specification of a demonstration FBR, the measures for promoting international cooperation, and other important matters. As the results of investigation, the situation around the development of FBRs, the fundamentals at the time of promoting the research and development, the subjects of the research and development and so on are reported. (Kako, I.)
International Nuclear Information System (INIS)
Stone, Craig A.
1999-01-01
Scientific Digital Visions, Inc. developed methods of accessing and dissemination nuclear data contained within the databases of the National Data Center (NNDC) at the Brookhaven National Laboratory supporting a long standing and important DOE Program to provide scientists access to NNDC Databases. The NNDC participated as a partner in this effort
DEFF Research Database (Denmark)
Nielsen, Kristian Fog; Thrane, Ulf
2001-01-01
The paper presents a fast method for trichothecene profiling and chemotaxonomic studies in species of Fusarium, Stachybotrys, Trichoderma and Memnoniella. Micro scale extracted crude Fusarium extracts were derivatised using pentafluoropropionic anhydride and analysed by gas chromatography...
A program-compiling method of nuclear data on-line fast analysis
International Nuclear Information System (INIS)
Li Shangbai
1990-01-01
This paper discusses how to perform assembly float point operation by using some subroutine of applesoft system, and a program compiling method of nuclear data fast analysis in apple microcomputer is introduced
Improved method of generating bit reversed numbers for calculating fast fourier transform
Digital Repository Service at National Institute of Oceanography (India)
Suresh, T.
Fast Fourier Transform (FFT) is an important tool required for signal processing in defence applications. This paper reports an improved method for generating bit reversed numbers needed in calculating FFT using radix-2. The refined algorithm takes...
The analysis of RPV fast neutron flux calculation for PWR with three-dimensional SN method
International Nuclear Information System (INIS)
Yang Shouhai; Chen Yixue; Wang Weijin; Shi Shengchun; Lu Daogang
2011-01-01
Discrete ordinates (S N ) method is one of the most widely used method for reactor pressure vessel (RPV) design. As the fast development of computer CPU speed and memory capacity and consummation of three-dimensional discrete-ordinates method, it is mature for 3-D S N method to be used to engineering design for nuclear facilities. This work was done specifically for PWR model, with the results of 3-D core neutron transport calculation by 3-D core calculation, 3-D RPV fast neutron flux distribution obtain by 3-D S N method were compared with gained by 1-D and 2-D S N method and the 3-D Monte Carlo (MC) method. In this paper, the application of three-dimensional S N method in calculating RPV fast neutron flux distribution for pressurized water reactor (PWR) is presented and discussed. (authors)
International Nuclear Information System (INIS)
Amano, Yukiya
2013-01-01
Public confidence in nuclear power was greatly shaken by the Fukushima Daiichi accident. It will take time to rebuild that confidence. This will only be possible if everyone involved in nuclear power has a total commitment to safety and if the sector is open and transparent. The public need to be reassured that nuclear energy is efficient and safe, can mitigate the effects of climate change and can play a key role in meeting the growing global demand for energy. Fast reactors and related fuel cycles will be important for the long-term sustainability of nuclear power. This innovative technology has the potential to ensure that energy resources which would run out in a few hundred years, using today’s technology, will actually last several thousand years. Fast reactors also reduce the volume and toxicity of the final waste. China’s Experimental Fast Reactor has been connected to the grid. Work is at an advanced stage on construction of India’s 500 MW(e) Prototype Fast Breeder Reactor and of the large BN-800 reactor in the Russian Federation. Interest in fast reactors with closed fuel cycles is increasing steadily. A number of emerging economies are joining the existing fast reactor technology-holders. Considerable R & D work is being done on advanced designs with enhanced safety characteristics. It is important to gather the operational experience of countries with operating fast reactors and related fuel cycle facilities. This can help to achieve higher levels of safety. Events such as the Joint GIF-IAEA Workshop on the safety of sodium-cooled fast reactors last week are a useful way of doing this. They also help to ensure that relevant lessons from the Fukushima Daiichi accident are learned. The IAEA remains the unique collaboration forum for ensuring continued progress in fast reactor technology. We provide an umbrella for knowledge preservation, information exchange and collaborative R&D in which resources and expertise are pooled
Methods to determine fast-ion distribution functions from multi-diagnostic measurements
DEFF Research Database (Denmark)
Jacobsen, Asger Schou; Salewski, Mirko
-ion diagnostic views, it is possible to infer the distribution function using a tomography approach. Several inversion methods for solving this tomography problem in velocity space are implemented and compared. It is found that the best quality it obtained when using inversion methods which penalise steep......Understanding the behaviour of fast ions in a fusion plasma is very important, since the fusion-born alpha particles are expected to be the main source of heating in a fusion power plant. Preferably, the entire fast-ion velocity-space distribution function would be measured. However, no fast...
A fast template matching method for LED chip Localization
Directory of Open Access Journals (Sweden)
Zhong Fuqiang
2015-01-01
Full Text Available Efficiency determines the profits of the semiconductor producers. So the producers spare no effort to enhance the efficiency of every procedure. The purpose of the paper is to present a method to shorten the time to locate the LED chips on wafer. The method consists of 3 steps. Firstly, image segmentation and blob analyzation are used to predict the positions of potential chips. Then predict the orientations of potential chips based on their dominant orientations. Finally, according to the positions and orientations predicted above, locate the chips precisely based on gradient orientation features. Experiments show that the algorithm is faster than the traditional method we choose to locate the LED chips. Besides, even the orientations of the chips on wafer are of big deviation to the orientation of the template, the efficiency of this method won't be affected.
A fast nodal neutron diffusion method for cartesian geometry
International Nuclear Information System (INIS)
Makai, M.; Maeder, C.
1983-01-01
A numerical method based on an analytical solution to the three-dimensional two-group diffusion equation has been derived assuming that the flux is a sum of the functions of one variable. In each mesh the incoming currents are used as boundary conditions. The final equations for the average flux and the outgoing currents are of the response matrix type. The method is presented in a form that can be extended to the general multigroup case. In the SEXI computer program developed on the basis of this method, the response matrix elements are recalculated in each outer iteration to minimize the data transfer between disk storage and central memory. The efficiency of the method is demonstrated for a light water reactor (LWR) benchmark problem. The SEXI program has been incorporated into the LWR simulator SILWER code as a possible option
Photostimulated luminescence, fast method of detection of irradiated foodstuffs
International Nuclear Information System (INIS)
Guzik, G.P.; Stachowicz, W.
2005-01-01
The principle of pulsed photostimulated luminescence (PPSL) method, description of instrumentation and methodology of measurements are presented. The pathway of operational procedure and testing of the PPSL instrument in the Laboratory for Detection of Irradiated Food of the Institute of Nuclear Chemistry and Technology are described. Attention has been paid to the positives of the new method while some limitation of its application have been also discussed. (author)
Energy Technology Data Exchange (ETDEWEB)
Stock, L.M.
1990-12-31
This report concerns our research on base-catalyzed coal solubilization and a new approach for hydrogen addition. The work on base-catalyzed, chemical solubilization is continuing. this report is focused on the hydrogenation research. Specifically it deals with the use of arene chromium carbonyl complexes as reagents for the addition of dideuterium to coal molecules. In one phase of the work, he has established that the aromatic hydrocarbons in a representative coal liquid can be converted in very good yield to arene chromium carbonyl compounds. In a second phase of the work directly related to our objective of improved methods for catalytic hydrogenation, he has established that the aromatic constituents of the same coal liquid add dideuterium in the presence of added napththalene chromium carbonyl.
A Fast Soft Bit Error Rate Estimation Method
Directory of Open Access Journals (Sweden)
Ait-Idir Tarik
2010-01-01
Full Text Available We have suggested in a previous publication a method to estimate the Bit Error Rate (BER of a digital communications system instead of using the famous Monte Carlo (MC simulation. This method was based on the estimation of the probability density function (pdf of soft observed samples. The kernel method was used for the pdf estimation. In this paper, we suggest to use a Gaussian Mixture (GM model. The Expectation Maximisation algorithm is used to estimate the parameters of this mixture. The optimal number of Gaussians is computed by using Mutual Information Theory. The analytical expression of the BER is therefore simply given by using the different estimated parameters of the Gaussian Mixture. Simulation results are presented to compare the three mentioned methods: Monte Carlo, Kernel and Gaussian Mixture. We analyze the performance of the proposed BER estimator in the framework of a multiuser code division multiple access system and show that attractive performance is achieved compared with conventional MC or Kernel aided techniques. The results show that the GM method can drastically reduce the needed number of samples to estimate the BER in order to reduce the required simulation run-time, even at very low BER.
Fast Reduction Method in Dominance-Based Information Systems
Li, Yan; Zhou, Qinghua; Wen, Yongchuan
2018-01-01
In real world applications, there are often some data with continuous values or preference-ordered values. Rough sets based on dominance relations can effectively deal with these kinds of data. Attribute reduction can be done in the framework of dominance-relation based approach to better extract decision rules. However, the computational cost of the dominance classes greatly affects the efficiency of attribute reduction and rule extraction. This paper presents an efficient method of computing dominance classes, and further compares it with traditional method with increasing attributes and samples. Experiments on UCI data sets show that the proposed algorithm obviously improves the efficiency of the traditional method, especially for large-scale data.
Multiple HEPA filter test methods, July 1, 1974--March 31, 1975
International Nuclear Information System (INIS)
Schuster, B.G.; Osetek, D.J.
1975-08-01
A laboratory apparatus has been constructed for testing two HEPA filters in a series configuration. The apparatus consists of an instrumented wind tunnel in which the HEPA filters are mounted, and an auxiliary wind tunnel for obtaining diluted samples of the challenge aerosol upstream of the first filter. Measurements performed with a single particle aerosol spectrometer demonstrate the capability for measuring overall protection factors of greater than 2.5 x 10 8 . The decay of penetration as a function of time in individual HEPA filters indicates no preferential size discrimination in the range of 0.1 μm to 1.0 μm; nor is there a preferential size discrimination of penetration in this same range. A theoretical feasibility study has been performed on the use of an inhomogeneous electric field/induced aerosol electric dipole interaction for potential use as an air cleaning mechanism. Numerical evaluation of a coaxial cylinder geometry indicates that the method is feasible for collection of particles down to 0.1 μm under typical airflow velocity conditions. Small modifications in the geometry may be incorporated to create an instrument capable of measuring particle size. Geometries other than coaxial cylinders are also under investigation
Fast analytical method for the addition of random variables
International Nuclear Information System (INIS)
Senna, V.; Milidiu, R.L.; Fleming, P.V.; Salles, M.R.; Oliveria, L.F.S.
1983-01-01
Using the minimal cut sets representation of a fault tree, a new approach to the method of moments is proposed in order to estimate confidence bounds to the top event probability. The method utilizes two or three moments either to fit a distribution (the normal and lognormal families) or to evaluate bounds from standard inequalities (e.g. Markov, Tchebycheff, etc.) Examples indicate that the results obtained by the log-normal family are in good agreement with those obtained by Monte Carlo simulation
A Fast and Effective Block Adjustment Method with Big Data
Directory of Open Access Journals (Sweden)
ZHENG Maoteng
2017-02-01
Full Text Available To deal with multi-source, complex and massive data in photogrammetry, and solve the high memory requirement and low computation efficiency of irregular normal equation caused by the randomly aligned and large scale datasets, we introduce the preconditioned conjugate gradient combined with inexact Newton method to solve the normal equation which do not have strip characteristics due to the randomly aligned images. We also use an effective sparse matrix compression format to compress the big normal matrix, a brand new workflow of bundle adjustment is developed. Our method can avoid the direct inversion of the big normal matrix, the memory requirement of the normal matrix is also decreased by the proposed sparse matrix compression format. Combining all these techniques, the proposed method can not only decrease the memory requirement of normal matrix, but also largely improve the efficiency of bundle adjustment while maintaining the same accuracy as the conventional method. Preliminary experiment results show that the bundle adjustment of a dataset with about 4500 images and 9 million image points can be done in only 15 minutes while achieving sub-pixel accuracy.
Fast Numerical Methods for Stochastic Partial Differential Equations
2016-04-15
Particle Swarm Optimization (PSO) method. Inspired by the social behavior of the bird flocking or fish schooling, the particle swarm optimization (PSO...Weerasinghe, Hongmei Chi and Yanzhao Cao, Particle Swarm Optimization Simulation via Optimal Halton Sequences, accepted by Procedia Computer Science (2016...Optimization Simulation via Optimal Halton Sequences, accepted by Procedia Computer Science (2016). 2. Haiyan Tian, Hongmei Chi and Yanzhao Cao
Fast methods for spatially correlated multilevel functional data
Staicu, A.-M.; Crainiceanu, C. M.; Carroll, R. J.
2010-01-01
-one-out analyses, and nonparametric bootstrap sampling. Our methods are inspired by and applied to data obtained from a state-of-the-art colon carcinogenesis scientific experiment. However, our models are general and will be relevant to many new data sets where
Directory of Open Access Journals (Sweden)
A. Becker
2003-01-01
Full Text Available In this paper a hybrid method combining the FDTD/FIT with a Time Domain Boundary-Integral Marching-on-in-Time Algorithm (TD-BIM is presented. Inhomogeneous regions are modelled with the FIT-method, an alternative formulation of the FDTD. Homogeneous regions (which is in the presented numerical example the open space are modelled using a TD-BIM with equivalent electric and magnetic currents flowing on the boundary between the inhomogeneous and the homogeneous regions. The regions are coupled by the tangential magnetic fields just outside the inhomogeneous regions. These fields are calculated by making use of a Mixed Potential Integral Formulation for the magnetic field. The latter consists of equivalent electric and magnetic currents on the boundary plane between the homogeneous and the inhomogeneous region. The magnetic currents result directly from the electric fields of the Yee lattice. Electric currents in the same plane are calculated by making use of the TD-BIM and using the electric field of the Yee lattice as boundary condition. The presented hybrid method only needs the interpolations inherent in FIT and no additional interpolation. A numerical result is compared to a calculation that models both regions with FDTD.
Captive solvent methods for fast, simple carbon-11 radioalkylations
International Nuclear Information System (INIS)
Jewett, D.M.; Mangner, T.J.; Watkins, G.L.
1991-01-01
Carbon-11 labeled radiopharmaceuticals for receptor studies usually require final purification by high performance liquid chromatography (HPLC). A significant simplification of the apparatus is possible if the radiolabeling reaction can be done directly in the HPLC injection circuit. Captive solvent methods in which the reaction is done in a small volume of solvent absorbed in a porous solid matrix are a general approach to this problem. For N-methylations with [ 11 C] methyl iodide, a basic catalyst may be incorporated in the polymeric or alumina solid phase. Reaction volumes are from 20 to 100 ML. Often no heating or cooling of the reaction column is necessary. The syntheses of [ 11 C]PK11195 and [ 11 C] flumazenil are described to illustrate some of the advantages and limitations of captive solvent methods
Energy spectra of fast neutrons by nuclear emulsion method
International Nuclear Information System (INIS)
Quaresma, A.A.
1977-01-01
An experimental method which uses nuclear emulsion plates to determine the energy spectrum of fission neutrons is described. By using this technique, we have obtained the energy distribution of neutrons from spontaneous fission of Cf 2 5 2 . The results are in good agreement with whose obtained previously by others authors who have used different detection techniques, and they are consistent with a Maxwellian distribution as expected by Weisskopf's nuclear evaporation theory. (author)
Fast film dosimetry calibration method for IMRT treatment plan verification
International Nuclear Information System (INIS)
Schwob, N.; Wygoda, A.
2004-01-01
Intensity-Modulated Radiation Therapy (IMRT) treatments are delivered dynamically and as so, require routinely performed verification measurements [1]. Radiographic film dosimetry is a well-adapted method for integral measurements of dynamic treatments fields, with some drawbacks related to the known problems of dose calibration of films. Classically, several films are exposed to increasing doses, and a Net Optical Density (N.O.D) vs. dose sensitometric curve (S.C.) is generated. In order to speed up the process, some authors have developed a method based on the irradiation of a single film with a non-uniform pattern of O.D., delivered with a dynamic MLC. However, this curve still needs to be calibrated to dose by the means of measurements in a water phantom. It is recommended to make a new calibration for every series of measurements, in order to avoid the processing quality dependence of the film response. These frequent measurements are very time consuming. We developed a simple method for quick dose calibration of films, including a check of the accuracy of the calibration curve obtained
New simple method for fast and accurate measurement of volumes
International Nuclear Information System (INIS)
Frattolillo, Antonio
2006-01-01
A new simple method is presented, which allows us to measure in just a few minutes but with reasonable accuracy (less than 1%) the volume confined inside a generic enclosure, regardless of the complexity of its shape. The technique proposed also allows us to measure the volume of any portion of a complex manifold, including, for instance, pipes and pipe fittings, valves, gauge heads, and so on, without disassembling the manifold at all. To this purpose an airtight variable volume is used, whose volume adjustment can be precisely measured; it has an overall capacity larger than that of the unknown volume. Such a variable volume is initially filled with a suitable test gas (for instance, air) at a known pressure, as carefully measured by means of a high precision capacitive gauge. By opening a valve, the test gas is allowed to expand into the previously evacuated unknown volume. A feedback control loop reacts to the resulting finite pressure drop, thus contracting the variable volume until the pressure exactly retrieves its initial value. The overall reduction of the variable volume achieved at the end of this process gives a direct measurement of the unknown volume, and definitively gets rid of the problem of dead spaces. The method proposed actually does not require the test gas to be rigorously held at a constant temperature, thus resulting in a huge simplification as compared to complex arrangements commonly used in metrology (gas expansion method), which can grant extremely accurate measurement but requires rather expensive equipments and results in time consuming methods, being therefore impractical in most applications. A simple theoretical analysis of the thermodynamic cycle and the results of experimental tests are described, which demonstrate that, in spite of its simplicity, the method provides a measurement accuracy within 0.5%. The system requires just a few minutes to complete a single measurement, and is ready immediately at the end of the process. The
A contribution to the method of fast reactor thermal output calculation
International Nuclear Information System (INIS)
Harant, M.
1978-01-01
The method of stating the heat sources is discussed as being one of the factors influencing the accuracy of the thermal output calculation of fast reactors. The distribution of heat sources in the core and in other inner parts of the fast reactor is described using the least square fit method. Relations are derived of outputs of both individual components of fuel elements and of whole inner parts of the reactor. A comparison is made of various methods used for obtaining source integrals. The optimum integration method was found. (author)
A second order discontinuous Galerkin fast sweeping method for Eikonal equations
Li, Fengyan; Shu, Chi-Wang; Zhang, Yong-Tao; Zhao, Hongkai
2008-09-01
In this paper, we construct a second order fast sweeping method with a discontinuous Galerkin (DG) local solver for computing viscosity solutions of a class of static Hamilton-Jacobi equations, namely the Eikonal equations. Our piecewise linear DG local solver is built on a DG method developed recently [Y. Cheng, C.-W. Shu, A discontinuous Galerkin finite element method for directly solving the Hamilton-Jacobi equations, Journal of Computational Physics 223 (2007) 398-415] for the time-dependent Hamilton-Jacobi equations. The causality property of Eikonal equations is incorporated into the design of this solver. The resulting local nonlinear system in the Gauss-Seidel iterations is a simple quadratic system and can be solved explicitly. The compactness of the DG method and the fast sweeping strategy lead to fast convergence of the new scheme for Eikonal equations. Extensive numerical examples verify efficiency, convergence and second order accuracy of the proposed method.
Fast and precise method of contingency ranking in modern power system
DEFF Research Database (Denmark)
Rather, Zakir Hussain; Chen, Zhe; Thøgersen, Paul
2011-01-01
Contingency Analysis is one of the most important aspect of Power System Security Analysis. This paper presents a fast and precise method of contingency ranking for effective power system security analysis. The method proposed in this research work takes due consideration of both apparent power o...... is based on realistic approach taking practical situations into account. Besides taking real situations into consideration the proposed method is fast enough to be considered for on-line security analysis.......Contingency Analysis is one of the most important aspect of Power System Security Analysis. This paper presents a fast and precise method of contingency ranking for effective power system security analysis. The method proposed in this research work takes due consideration of both apparent power...
Infrared thermography method for fast estimation of phase diagrams
Energy Technology Data Exchange (ETDEWEB)
Palomo Del Barrio, Elena [Université de Bordeaux, Institut de Mécanique et d’Ingénierie, Esplanade des Arts et Métiers, 33405 Talence (France); Cadoret, Régis [Centre National de la Recherche Scientifique, Institut de Mécanique et d’Ingénierie, Esplanade des Arts et Métiers, 33405 Talence (France); Daranlot, Julien [Solvay, Laboratoire du Futur, 178 Av du Dr Schweitzer, 33608 Pessac (France); Achchaq, Fouzia, E-mail: fouzia.achchaq@u-bordeaux.fr [Université de Bordeaux, Institut de Mécanique et d’Ingénierie, Esplanade des Arts et Métiers, 33405 Talence (France)
2016-02-10
Highlights: • Infrared thermography is proposed to determine phase diagrams in record time. • Phase boundaries are detected by means of emissivity changes during heating. • Transition lines are identified by using Singular Value Decomposition techniques. • Different binary systems have been used for validation purposes. - Abstract: Phase change materials (PCM) are widely used today in thermal energy storage applications. Pure PCMs are rarely used because of non adapted melting points. Instead of them, mixtures are preferred. The search of suitable mixtures, preferably eutectics, is often a tedious and time consuming task which requires the determination of phase diagrams. In order to accelerate this screening step, a new method for estimating phase diagrams in record time (1–3 h) has been established and validated. A sample composed by small droplets of mixtures with different compositions (as many as necessary to have a good coverage of the phase diagram) deposited on a flat substrate is first prepared and cooled down to ambient temperature so that all droplets crystallize. The plate is then heated at constant heating rate up to a sufficiently high temperature for melting all the small crystals. The heating process is imaged by using an infrared camera. An appropriate method based on singular values decomposition technique has been developed to analyze the recorded images and to determine the transition lines of the phase diagram. The method has been applied to determine several simple eutectic phase diagrams and the reached results have been validated by comparison with the phase diagrams obtained by Differential Scanning Calorimeter measurements and by thermodynamic modelling.
A fast mollified impulse method for biomolecular atomistic simulations
Energy Technology Data Exchange (ETDEWEB)
Fath, L., E-mail: lukas.fath@kit.edu [Institute for App. and Num. Mathematics, Karlsruhe Institute of Technology (Germany); Hochbruck, M., E-mail: marlis.hochbruck@kit.edu [Institute for App. and Num. Mathematics, Karlsruhe Institute of Technology (Germany); Singh, C.V., E-mail: chandraveer.singh@utoronto.ca [Department of Materials Science & Engineering, University of Toronto (Canada)
2017-03-15
Classical integration methods for molecular dynamics are inherently limited due to resonance phenomena occurring at certain time-step sizes. The mollified impulse method can partially avoid this problem by using appropriate filters based on averaging or projection techniques. However, existing filters are computationally expensive and tedious in implementation since they require either analytical Hessians or they need to solve nonlinear systems from constraints. In this work we follow a different approach based on corotation for the construction of a new filter for (flexible) biomolecular simulations. The main advantages of the proposed filter are its excellent stability properties and ease of implementation in standard softwares without Hessians or solving constraint systems. By simulating multiple realistic examples such as peptide, protein, ice equilibrium and ice–ice friction, the new filter is shown to speed up the computations of long-range interactions by approximately 20%. The proposed filtered integrators allow step sizes as large as 10 fs while keeping the energy drift less than 1% on a 50 ps simulation.
Hanford environmental analytical methods (methods as of March 1990). Appendix A3-O and Appendix A3-I
Energy Technology Data Exchange (ETDEWEB)
Goheen, S.D.; McCulloch, M.; Daniel, J.L.
1993-05-01
Information is provided on the techniques employed towards the chemical analysis of volatile, semi-volatile matter, pesticides and PCB`s at the Hanford Reservation. Sample preparation methods are included.
Comparison of fast neutron-induced tracks in plastics using the electrochemical etching method
International Nuclear Information System (INIS)
Cotter, S.J.; Gammage, R.B.; Thorngate, J.H.; Ziemer, P.L.
1979-01-01
Four plastics were examined by the electrochemical etching method for their suitability in registering fast neutron-induced recoil particle tracks. The plastics were cellulose acetate, cellulose triacetate, cellulose acetobutyrate and polycarbonate. Cellulose acetate and triacetate displayed high levels of water absorptivity during etching while the acetobutyrate foils cracked due to electromechanical stresses at high frequencies (>500 Hz). The clarity of the etched track was superior in the polycarbonate foils, suggesting the latter as the generally preferred dosimeter for fast neutrons. (author)
The essential theory of fast wave current drive with full wave method
International Nuclear Information System (INIS)
Liu Yan; Gong Xueyu; Yang Lei; Yin Chenyan; Yin Lan
2007-01-01
The full wave numerical method is developed for analyzing fast wave current drive in the range of ion cyclotron waves in tokamak plasmas, taking into account finite larmor radius effects and parallel dispersion. the physical model, the dispersion relation on the assumption of Finite Larmor Radius (FLR) effects and the form of full wave be used for computer simulation are developed. All of the work will contribute to further study of fast wave current drive. (authors)
Fast synthesize ZnO quantum dots via ultrasonic method.
Yang, Weimin; Zhang, Bing; Ding, Nan; Ding, Wenhao; Wang, Lixi; Yu, Mingxun; Zhang, Qitu
2016-05-01
Green emission ZnO quantum dots were synthesized by an ultrasonic sol-gel method. The ZnO quantum dots were synthesized in various ultrasonic temperature and time. Photoluminescence properties of these ZnO quantum dots were measured. Time-resolved photoluminescence decay spectra were also taken to discover the change of defects amount during the reaction. Both ultrasonic temperature and time could affect the type and amount of defects in ZnO quantum dots. Total defects of ZnO quantum dots decreased with the increasing of ultrasonic temperature and time. The dangling bonds defects disappeared faster than the optical defects. Types of optical defects first changed from oxygen interstitial defects to oxygen vacancy and zinc interstitial defects. Then transformed back to oxygen interstitial defects again. The sizes of ZnO quantum dots would be controlled by both ultrasonic temperature and time as well. That is, with the increasing of ultrasonic temperature and time, the sizes of ZnO quantum dots first decreased then increased. Moreover, concentrated raw materials solution brought larger sizes and more optical defects of ZnO quantum dots. Copyright © 2015 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Laurent Michel
2013-01-01
For this opening address, I would like to share with you some thoughts about the evolution of the key drivers during the last decades for the development of fast reactors from the very pioneering age till now, taking into account new concerns and major events occurred since the last international conference on fast reactors and related fuel cycles held in Kyoto, Japan (FR 2009). There are three major periods: • The pioneering age (1945-1980) with breeding as a main driver followed by a kind of “winter season“ (1980-2000) for the development of fast reactors worldwide; • The so-called “brainstorming” phase (2000-2010), back to physics and nuclear chemistry, with international rebirth of the research on fast reactors and advanced fuel cycle owing to the GENERATION IV initiative, revisiting various reactor concepts along with 4 main drivers: sustainability, safety, proliferation resistance and costcompetitiveness. • A new era now (started in 2010) with very promising technological options and projects of prototypes with two main key drivers: → Innovation towards enhanced safety which is a major concern for public acceptance of nuclear power, especially after the FUKUSHIMA accident. → Higher flexibility in the management of fissile materials and nuclear waste in order to take into account various possible options for the contribution of nuclear power in the energy mix
Fast polarimetric dehazing method for visibility enhancement in HSI colour space
Zhang, Wenfei; Liang, Jian; Ren, Liyong; Ju, Haijuan; Bai, Zhaofeng; Wu, Zhaoxin
2017-09-01
Image haze removal has attracted much attention in optics and computer vision fields in recent years due to its wide applications. In particular, the fast and real-time dehazing methods are of significance. In this paper, we propose a fast dehazing method in hue, saturation and intensity colour space based on the polarimetric imaging technique. We implement the polarimetric dehazing method in the intensity channel, and the colour distortion of the image is corrected using the white patch retinex method. This method not only reserves the detailed information restoration capacity, but also improves the efficiency of the polarimetric dehazing method. Comparison studies with state of the art methods demonstrate that the proposed method obtains equal or better quality results and moreover the implementation is much faster. The proposed method is promising in real-time image haze removal and video haze removal applications.
Fast crawling methods of exploring content distributed over large graphs
Wang, Pinghui
2018-03-15
Despite recent effort to estimate topology characteristics of large graphs (e.g., online social networks and peer-to-peer networks), little attention has been given to develop a formal crawling methodology to characterize the vast amount of content distributed over these networks. Due to the large-scale nature of these networks and a limited query rate imposed by network service providers, exhaustively crawling and enumerating content maintained by each vertex is computationally prohibitive. In this paper, we show how one can obtain content properties by crawling only a small fraction of vertices and collecting their content. We first show that when sampling is naively applied, this can produce a huge bias in content statistics (i.e., average number of content replicas). To remove this bias, one may use maximum likelihood estimation to estimate content characteristics. However, our experimental results show that this straightforward method requires to sample most vertices to obtain accurate estimates. To address this challenge, we propose two efficient estimators: special copy estimator (SCE) and weighted copy estimator (WCE) to estimate content characteristics using available information in sampled content. SCE uses the special content copy indicator to compute the estimate, while WCE derives the estimate based on meta-information in sampled vertices. We conduct experiments on a variety of real-word and synthetic datasets, and the results show that WCE and SCE are cost effective and also “asymptotically unbiased”. Our methodology provides a new tool for researchers to efficiently query content distributed in large-scale networks.
A fast computing method to distinguish the hyperbolic trajectory of an non-autonomous system
Jia, Meng; Fan, Yang-Yu; Tian, Wei-Jian
2011-03-01
Attempting to find a fast computing method to DHT (distinguished hyperbolic trajectory), this study first proves that the errors of the stable DHT can be ignored in normal direction when they are computed as the trajectories extend. This conclusion means that the stable flow with perturbation will approach to the real trajectory as it extends over time. Based on this theory and combined with the improved DHT computing method, this paper reports a new fast computing method to DHT, which magnifies the DHT computing speed without decreasing its accuracy. Project supported by the National Natural Science Foundation of China (Grant No. 60872159).
A fast computing method to distinguish the hyperbolic trajectory of an non-autonomous system
International Nuclear Information System (INIS)
Jia Meng; Fan Yang-Yu; Tian Wei-Jian
2011-01-01
Attempting to find a fast computing method to DHT (distinguished hyperbolic trajectory), this study first proves that the errors of the stable DHT can be ignored in normal direction when they are computed as the trajectories extend. This conclusion means that the stable flow with perturbation will approach to the real trajectory as it extends over time. Based on this theory and combined with the improved DHT computing method, this paper reports a new fast computing method to DHT, which magnifies the DHT computing speed without decreasing its accuracy. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Fast sweeping methods for hyperbolic systems of conservation laws at steady state II
Engquist, Björn; Froese, Brittany D.; Tsai, Yen-Hsi Richard
2015-04-01
The idea of using fast sweeping methods for solving stationary systems of conservation laws has previously been proposed for efficiently computing solutions with sharp shocks. We further develop these methods to allow for a more challenging class of problems including problems with sonic points, shocks originating in the interior of the domain, rarefaction waves, and two-dimensional systems. We show that fast sweeping methods can produce higher-order accuracy. Computational results validate the claims of accuracy, sharp shock curves, and optimal computational efficiency.
Direct fourier method reconstruction based on unequally spaced fast fourier transform
International Nuclear Information System (INIS)
Wu Xiaofeng; Zhao Ming; Liu Li
2003-01-01
First, We give an Unequally Spaced Fast Fourier Transform (USFFT) method, which is more exact and theoretically more comprehensible than its former counterpart. Then, with an interesting interpolation scheme, we discusse how to apply USFFT to Direct Fourier Method (DFM) reconstruction of parallel projection data. At last, an emulation experiment result is given. (authors)
Design Method for Fast Switching Seat Valves for Digital Displacement Machines
DEFF Research Database (Denmark)
Roemer, Daniel Beck; Johansen, Per; Pedersen, Henrik C.
2014-01-01
corresponding to the piston movement, which has been shown to facilitate superior part load efficiency combined with high bandwidth compared to traditional displacement machines. However, DD machines need fast switching on-off valves with low pressure loss for efficient operation, especially in fast rotating......Digital Displacement (DD) machines are upcoming technology where the displacement of each pressure chamber is controlled electronically by use of two fast switching seat valves. The effective displacement and operation type (pumping/motoring) may be controlled by manipulating the seat valves...... method for DD seat valves are presented, taking into account the significant aspects related to obtaining efficient DD valves with basis in a given DD machine specifications. The seat area is minimized and the stroke length is minimized to obtain fast switching times while considering the pressure loss...
DEFF Research Database (Denmark)
McCloskey, Douglas; Utrilla, Jose; Naviaux, Robert K.
2015-01-01
, we develop a fast-filtration method using pressuredriven Swinnex filters. We show that the method is fast enough to provide an accurate snapshot of intracellular metabolism, reduces matrix interference from the media to improve the number of compounds that can be detected, and is applicable...... to anaerobic and aerobic liquid cultures grown in a variety of culturing systems. Furthermore, we apply the fast filtration method to investigate differences in the absolute intracellular metabolite levels of anaerobic cultures grown in minimal and complex media....
Chen, Fan; Huang, Shaoxiong; Ding, Jinjin; Ding, Jinjin; Gao, Bo; Xie, Yuguang; Wang, Xiaoming
2018-01-01
This paper proposes a fast reliability assessing method for distribution grid with distributed renewable energy generation. First, the Weibull distribution and the Beta distribution are used to describe the probability distribution characteristics of wind speed and solar irradiance respectively, and the models of wind farm, solar park and local load are built for reliability assessment. Then based on power system production cost simulation probability discretization and linearization power flow, a optimal power flow objected with minimum cost of conventional power generation is to be resolved. Thus a reliability assessment for distribution grid is implemented fast and accurately. The Loss Of Load Probability (LOLP) and Expected Energy Not Supplied (EENS) are selected as the reliability index, a simulation for IEEE RBTS BUS6 system in MATLAB indicates that the fast reliability assessing method calculates the reliability index much faster with the accuracy ensured when compared with Monte Carlo method.
Hybrid massively parallel fast sweeping method for static Hamilton–Jacobi equations
Energy Technology Data Exchange (ETDEWEB)
Detrixhe, Miles, E-mail: mdetrixhe@engineering.ucsb.edu [Department of Mechanical Engineering (United States); University of California Santa Barbara, Santa Barbara, CA, 93106 (United States); Gibou, Frédéric, E-mail: fgibou@engineering.ucsb.edu [Department of Mechanical Engineering (United States); University of California Santa Barbara, Santa Barbara, CA, 93106 (United States); Department of Computer Science (United States); Department of Mathematics (United States)
2016-10-01
The fast sweeping method is a popular algorithm for solving a variety of static Hamilton–Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling, and show state-of-the-art speedup values for the fast sweeping method.
Hybrid massively parallel fast sweeping method for static Hamilton–Jacobi equations
International Nuclear Information System (INIS)
Detrixhe, Miles; Gibou, Frédéric
2016-01-01
The fast sweeping method is a popular algorithm for solving a variety of static Hamilton–Jacobi equations. Fast sweeping algorithms for parallel computing have been developed, but are severely limited. In this work, we present a multilevel, hybrid parallel algorithm that combines the desirable traits of two distinct parallel methods. The fine and coarse grained components of the algorithm take advantage of heterogeneous computer architecture common in high performance computing facilities. We present the algorithm and demonstrate its effectiveness on a set of example problems including optimal control, dynamic games, and seismic wave propagation. We give results for convergence, parallel scaling, and show state-of-the-art speedup values for the fast sweeping method.
Combined method for the fast determination of pure beta emitting radioisotopes in food samples
International Nuclear Information System (INIS)
Kabai, Eva; Savkin, Birgit; Mehlsam, Isabell; Poppitz-Spuhler, Angela
2017-01-01
Fast radioanalytical methods are essential for a rapid response of decision makers. A fast method for the simultaneous determination of the pure beta emitting radionuclides 89 Sr/ 90 Sr and 99 Tc in food samples was developed. It includes the precipitation of fat and proteins with trichloroacetic acid for milk and dairy products and microwave digestion for other food products, followed by an anion exchange step to separate strontium from technetium. The purification steps for strontium and technetium are done using Sr-resin and TEVA-resin, respectively. Typical chemical yields are around 70 % for both radionuclides. The whole determination takes only around 20 h. (author)
Application of synthesis methods to two-dimensional fast reactor transient study
International Nuclear Information System (INIS)
Izutsu, Sadayuki; Hirakawa, Naohiro
1978-01-01
Space time synthesis and time synthesis codes were developed and applied to the space-dependent kinetics benchmark problem of a two-dimensional fast reactor model, and it was found both methods are accurate and economical for the fast reactor kinetics study. Comparison between the space time synthesis and the time synthesis was made. Also, in space time synthesis, the influence of the number of trial functions on the error and on the computing time and the effect of degeneration of expansion coefficients are investigated. The matrix factorization method is applied to the inversion of the matrix equation derived from the synthesis equation, and it is indicated that by the use of this scheme space-dependent kinetics problem of a fast reactor can be solved efficiently by space time synthesis. (auth.)
International Nuclear Information System (INIS)
Bigot, Bernard
2013-01-01
• In spite of the recent Fukushima accident, the use of nuclear energy still remains a necessity for many countries With a mastered and always improved safety, nuclear energy will go on contributing to the world energy needs, reducing fossil fuel dependency and GHG emissions. • With the help of large international collaborations, CEA is committed to demonstrate potential pathways for making significant progress for future fast neutrons reactors and their corresponding fuel cycle. • In synergy with nuclear energy, the renewable energies must be widely developed
FCNN-MR: A Parallel Instance Selection Method Based on Fast Condensed Nearest Neighbor Rule
Lu Si; Jie Yu; Shasha Li; Jun Ma; Lei Luo; Qingbo Wu; Yongqi Ma; Zhengji Liu
2017-01-01
Instance selection (IS) technique is used to reduce the data size to improve the performance of data mining methods. Recently, to process very large data set, several proposed methods divide the training set into some disjoint subsets and apply IS algorithms independently to each subset. In this paper, we analyze the limitation of these methods and give our viewpoint about how to divide and conquer in IS procedure. Then, based on fast condensed nearest neighbor (FCNN) rul...
Sui, Sai; Ma, Hua; Lv, Yueguang; Wang, Jiafu; Li, Zhiqiang; Zhang, Jieqiu; Xu, Zhuo; Qu, Shaobo
2018-01-22
Arbitrary control of electromagnetic waves remains a significant challenge although it promises many important applications. Here, we proposed a fast optimization method of designing a wideband metasurface without using the Pancharatnam-Berry (PB) phase, of which the elements are non-absorptive and capable of predicting the wideband and smooth phase-shift. In our design method, the metasurface is composed of low-Q-factor resonant elements without using the PB phase, and is optimized by the genetic algorithm and nonlinear fitting method, having the advantages that the far field scattering patterns can be quickly synthesized by the hybrid array patterns. To validate the design method, a wideband low radar cross section metasurface is demonstrated, showing good feasibility and performance of wideband RCS reduction. This work reveals an opportunity arising from a metasurface in effective manipulation of microwave and flexible fast optimal design method.
Using the SAND-II and MLM methods to reconstruct fast neutron spectra
International Nuclear Information System (INIS)
Bondars, Kh.Ya.; Kamnev, V.A.; Lapenas, A.A.; Troshin, V.S.
1981-01-01
The reconstruction of fast neutron spectra from measured reaction rates may be reduced to the solution of Fredholm's integral equation of the first kind. This problem falls in the category of incorrectly formulated problems, and so additional information is required concerning the unknown function i.e. concerning the differential energy dependence of the neutron, flux density sup(phi)(E). There are various methods for seeking a solution to the problem as formulated above. One of the best-known methods used in the USSR is the maximum likelihood method (MLM) (or directional difference method (DDM)), whereas SAND-II is commonly used abroad. The purpose of this paper is to compare the MLM and SAND-II methods, taking as an example the processing of measurement data which were obtained in the B-2 beam line at the BR-10 reactor in order to determine the composition of shielding for a fast reactor
DEFF Research Database (Denmark)
Meier, Robert J.; Gundersen Deslauriers, Maria; Woodley, John
2015-01-01
A simple, easy-to-use, and fast approach method is proposed and validated that can predict whether a transaminase reaction is thermodynamically unfavourable. This allowed us to de-select, in the present case, at least 50% of the reactions because they were thermodynamically unfavourable as confir...
Recent Development of Radioanalytical Methods at the IBR-2 Pulsed Fast Reactor
International Nuclear Information System (INIS)
Nazarov, V.M.; Peresedov, V.F.
1994-01-01
Experience in the application of radioanalytical methods, including NAA, at the IBR-2 pulsed fast reactor is reviewed. Details of the instruments dedicated to neutron activation analysis and radiography studies are reported. Applications of resonance neutrons to environmental monitoring and to the investigation of high-purity materials, are examplified. 15 refs. 9 figs., 9 tabs
A fast nonlinear conjugate gradient based method for 3D frictional contact problems
Zhao, J.; Vollebregt, E.A.H.; Oosterlee, C.W.
2014-01-01
This paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from a 3D frictional contact problem. It incorporates an active set strategy with a nonlinear conjugate gradient method. One novelty is to consider the tractions of each slip element in a polar
A fast nonlinear conjugate gradient based method for 3D concentrated frictional contact problems
J. Zhao (Jing); E.A.H. Vollebregt (Edwin); C.W. Oosterlee (Cornelis)
2015-01-01
htmlabstractThis paper presents a fast numerical solver for a nonlinear constrained optimization problem, arising from 3D concentrated frictional shift and rolling contact problems with dry Coulomb friction. The solver combines an active set strategy with a nonlinear conjugate gradient method. One
The Schrodinger Eigenvalue March
Tannous, C.; Langlois, J.
2011-01-01
A simple numerical method for the determination of Schrodinger equation eigenvalues is introduced. It is based on a marching process that starts from an arbitrary point, proceeds in two opposite directions simultaneously and stops after a tolerance criterion is met. The method is applied to solving several 1D potential problems including symmetric…
Study on the betterment of fast drying quality of Myamar lacquer through modification method
International Nuclear Information System (INIS)
Khine-Khine-Tun; Khin-May-Lwin
2001-08-01
Nowadays, only crude resins are used for lacquer wares. In Myanmar lacquer ware makers have not yet used modification methods for fast drying and brightness to improve the quality as in the Japanese lacquer wares. Thus it takes about three months to season the lacquer wares. The main factor which delays the seasoning is the slow process of drying of thitsi (Myanmar lacquer), which is extracted from naturally grown Melanorrhoea usitata Wall. This paper is attempted to find ways for fast drying process. It was found that drying in the oven at 100 0 C is the suitable treatment for commercial scale production. (author)
Palmesi, P.; Abert, C.; Bruckner, F.; Suess, D.
2018-05-01
Fast stray field calculation is commonly considered of great importance for micromagnetic simulations, since it is the most time consuming part of the simulation. The Fast Multipole Method (FMM) has displayed linear O(N) parallelization behavior on many cores. This article investigates the error of a recent FMM approach approximating sources using linear—instead of constant—finite elements in the singular integral for calculating the stray field and the corresponding potential. After measuring performance in an earlier manuscript, this manuscript investigates the convergence of the relative L2 error for several FMM simulation parameters. Various scenarios either calculating the stray field directly or via potential are discussed.
A hybrid source-driven method to compute fast neutron fluence in reactor pressure vessel - 017
International Nuclear Information System (INIS)
Ren-Tai, Chiang
2010-01-01
A hybrid source-driven method is developed to compute fast neutron fluence with neutron energy greater than 1 MeV in nuclear reactor pressure vessel (RPV). The method determines neutron flux by solving a steady-state neutron transport equation with hybrid neutron sources composed of peripheral fixed fission neutron sources and interior chain-reacted fission neutron sources. The relative rod-by-rod power distribution of the peripheral assemblies in a nuclear reactor obtained from reactor core depletion calculations and subsequent rod-by-rod power reconstruction is employed as the relative rod-by-rod fixed fission neutron source distribution. All fissionable nuclides other than U-238 (such as U-234, U-235, U-236, Pu-239 etc) are replaced with U-238 to avoid counting the fission contribution twice and to preserve fast neutron attenuation for heavy nuclides in the peripheral assemblies. An example is provided to show the feasibility of the method. Since the interior fuels only have a marginal impact on RPV fluence results due to rapid attenuation of interior fast fission neutrons, a generic set or one of several generic sets of interior fuels can be used as the driver and only the neutron sources in the peripheral assemblies will be changed in subsequent hybrid source-driven fluence calculations. Consequently, this hybrid source-driven method can simplify and reduce cost for fast neutron fluence computations. This newly developed hybrid source-driven method should be a useful and simplified tool for computing fast neutron fluence at selected locations of interest in RPV of contemporary nuclear power reactors. (authors)
Fast methods for long-range interactions in complex systems. Lecture notes
International Nuclear Information System (INIS)
Sutmann, Godehard; Gibbon, Paul; Lippert, Thomas
2011-01-01
Parallel computing and computer simulations of complex particle systems including charges have an ever increasing impact in a broad range of fields in the physical sciences, e.g. in astrophysics, statistical physics, plasma physics, material sciences, physical chemistry, and biophysics. The present summer school, funded by the German Heraeus-Foundation, took place at the Juelich Supercomputing Centre from 6 - 10 September 2010. The focus was on providing an introduction and overview over different methods, algorithms and new trends for the computational treatment of long-range interactions in particle systems. The Lecture Notes contain an introduction into particle simulation, as well as five different fast methods, i.e. the Fast Multipole Method, Barnes-Hut Tree Method, Multigrid, FFT based methods, and Fast Summation using the non-equidistant FFT. In addition to introducing the methods, efficient parallelization of the methods is presented in detail. This publication was edited at the Juelich Supercomputing Centre (JSC) which is an integral part of the Institute for Advanced Simulation (IAS). The IAS combines the Juelich simulation sciences and the supercomputer facility in one organizational unit. It includes those parts of the scientific institutes at Forschungszentrum Juelich which use simulation on supercomputers as their main research methodology. (orig.)
Fast methods for long-range interactions in complex systems. Lecture notes
Energy Technology Data Exchange (ETDEWEB)
Sutmann, Godehard; Gibbon, Paul; Lippert, Thomas (eds.)
2011-10-13
Parallel computing and computer simulations of complex particle systems including charges have an ever increasing impact in a broad range of fields in the physical sciences, e.g. in astrophysics, statistical physics, plasma physics, material sciences, physical chemistry, and biophysics. The present summer school, funded by the German Heraeus-Foundation, took place at the Juelich Supercomputing Centre from 6 - 10 September 2010. The focus was on providing an introduction and overview over different methods, algorithms and new trends for the computational treatment of long-range interactions in particle systems. The Lecture Notes contain an introduction into particle simulation, as well as five different fast methods, i.e. the Fast Multipole Method, Barnes-Hut Tree Method, Multigrid, FFT based methods, and Fast Summation using the non-equidistant FFT. In addition to introducing the methods, efficient parallelization of the methods is presented in detail. This publication was edited at the Juelich Supercomputing Centre (JSC) which is an integral part of the Institute for Advanced Simulation (IAS). The IAS combines the Juelich simulation sciences and the supercomputer facility in one organizational unit. It includes those parts of the scientific institutes at Forschungszentrum Juelich which use simulation on supercomputers as their main research methodology. (orig.)
Zhao, Yu; Shi, Chen-Xiao; Kwon, Ki-Chul; Piao, Yan-Ling; Piao, Mei-Lan; Kim, Nam
2018-03-01
We propose a fast calculation method for a computer-generated hologram (CGH) of real objects that uses a point cloud gridding method. The depth information of the scene is acquired using a depth camera and the point cloud model is reconstructed virtually. Because each point of the point cloud is distributed precisely to the exact coordinates of each layer, each point of the point cloud can be classified into grids according to its depth. A diffraction calculation is performed on the grids using a fast Fourier transform (FFT) to obtain a CGH. The computational complexity is reduced dramatically in comparison with conventional methods. The feasibility of the proposed method was confirmed by numerical and optical experiments.
Infrared video based gas leak detection method using modified FAST features
Wang, Min; Hong, Hanyu; Huang, Likun
2018-03-01
In order to detect the invisible leaking gas that is usually dangerous and easily leads to fire or explosion in time, many new technologies have arisen in the recent years, among which the infrared video based gas leak detection is widely recognized as a viable tool. However, all the moving regions of a video frame can be detected as leaking gas regions by the existing infrared video based gas leak detection methods, without discriminating the property of each detected region, e.g., a walking person in a video frame may be also detected as gas by the current gas leak detection methods.To solve this problem, we propose a novel infrared video based gas leak detection method in this paper, which is able to effectively suppress strong motion disturbances.Firstly, the Gaussian mixture model(GMM) is used to establish the background model.Then due to the observation that the shapes of gas regions are different from most rigid moving objects, we modify the Features From Accelerated Segment Test (FAST) algorithm and use the modified FAST (mFAST) features to describe each connected component. In view of the fact that the statistical property of the mFAST features extracted from gas regions is different from that of other motion regions, we propose the Pixel-Per-Points (PPP) condition to further select candidate connected components.Experimental results show that the algorithm is able to effectively suppress most strong motion disturbances and achieve real-time leaking gas detection.
International Nuclear Information System (INIS)
Nigg, D.W.; Wemple, C.A.; Hartwell, J.K.; Harker, Y.D.; Venhuizen, J.R.; Risler, R.
1997-12-01
A closed-form direct method for unfolding neutron spectra from foil activation data is presented. The method is applied to measurements of the free-field neutron spectrum produced by the proton-cyclotron-based fast-neutron radiotherapy facility at the University of Washington (UW) School of Medicine. The results compare favorably with theoretical expectations based on an a-priori calculational model of the target and neutron beamline configuration of the UW facility
Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.
2014-05-01
Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in ambient air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C9-C15 BVOC composition of single plant emissions may be characterised within a 14.5 min analysis time. Moreover, in-situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an 11.7 min chromatographic separation time (increasing to 19.7 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). These analysis times potentially allow for a twofold to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in-situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC (OBVOC) linalool in ambient air. During this field deployment within a suburban forest
Inversion methods for fast-ion velocity-space tomography in fusion plasmas
DEFF Research Database (Denmark)
Jacobsen, Asger Schou; Stagner, L.; Salewski, Mirko
2016-01-01
Velocity-space tomography has been used to infer 2D fast-ion velocity distribution functions. Here we compare the performance of five different tomographic inversion methods: truncated singular value decomposition, maximum entropy, minimum Fisher information and zeroth and first-order Tikhonov...... regularization. The inversion methods are applied to fast-ion Dα measurements taken just before and just after a sawtooth crash in the ASDEX Upgrade tokamak as well as to synthetic measurements from different test distributions. We find that the methods regularizing by penalizing steep gradients or maximizing...... entropy perform best. We assess the uncertainty of the calculated inversions taking into account photon noise, uncertainties in the forward model as well as uncertainties introduced by the regularization which allows us to distinguish regions of high and low confidence in the tomographies. In high...
Fast multipole acceleration of the MEG/EEG boundary element method
International Nuclear Information System (INIS)
Kybic, Jan; Clerc, Maureen; Faugeras, Olivier; Keriven, Renaud; Papadopoulo, Theo
2005-01-01
The accurate solution of the forward electrostatic problem is an essential first step before solving the inverse problem of magneto- and electroencephalography (MEG/EEG). The symmetric Galerkin boundary element method is accurate but cannot be used for very large problems because of its computational complexity and memory requirements. We describe a fast multipole-based acceleration for the symmetric boundary element method (BEM). It creates a hierarchical structure of the elements and approximates far interactions using spherical harmonics expansions. The accelerated method is shown to be as accurate as the direct method, yet for large problems it is both faster and more economical in terms of memory consumption
Influence of Neutron Spectra Unfolding Method on Fast Neutron Dose Determination
International Nuclear Information System (INIS)
Marinkovic, P.
1991-01-01
Full text: Accuracy of knowing the fast neutron spectra has great influence on equivalent dose determination. In usual fast neutron spectrum measurements with scintillation detectors based on proton recoil, the main difficulty is confidence of unfolding method. In former ones variance of obtained result is usually great and negative values are possible too, which does means that we don't now exactly is obtained neutron spectrum real one. The new unfolding method based on Shanon's information theory, which gives non-negative spectrum and relative low variance, is obtained and appropriate numerical code for application in fast neutron spectrometry based on proton recoil is realized. In this method principle of maximum entropy and maximum likelihood are used together. Unknown group density distribution functions, which are considered as desired normalized mean neutron group flux, are constl u cted using only constrain of knowing mean value. Obtained distributions are consistent to available information (counts in NCA from proton recoil), while being maximally noncommittal with respect to all other unknown circumstances. For maximum likelihood principle, distribution functions around mean value of counts in the channels of MCA are taken to be Gauss function shape. Optimal non-negative solution is searched by means of Lagrange parameter method. Nonlinear system of equations, is solved using gradient and Newton iterative algorithm. Error covariance matrix is obtained too. (author)
Enhanced method of fast re-routing with load balancing in software-defined networks
Lemeshko, Oleksandr; Yeremenko, Oleksandra
2017-11-01
A two-level method of fast re-routing with load balancing in a software-defined network (SDN) is proposed. The novelty of the method consists, firstly, in the introduction of a two-level hierarchy of calculating the routing variables responsible for the formation of the primary and backup paths, and secondly, in ensuring a balanced load of the communication links of the network, which meets the requirements of the traffic engineering concept. The method provides implementation of link, node, path, and bandwidth protection schemes for fast re-routing in SDN. The separation in accordance with the interaction prediction principle along two hierarchical levels of the calculation functions of the primary (lower level) and backup (upper level) routes allowed to abandon the initial sufficiently large and nonlinear optimization problem by transiting to the iterative solution of linear optimization problems of half the dimension. The analysis of the proposed method confirmed its efficiency and effectiveness in terms of obtaining optimal solutions for ensuring balanced load of communication links and implementing the required network element protection schemes for fast re-routing in SDN.
Directory of Open Access Journals (Sweden)
Hui Liu
2015-01-01
Full Text Available The key problem of computer-aided diagnosis (CAD of lung cancer is to segment pathologically changed tissues fast and accurately. As pulmonary nodules are potential manifestation of lung cancer, we propose a fast and self-adaptive pulmonary nodules segmentation method based on a combination of FCM clustering and classification learning. The enhanced spatial function considers contributions to fuzzy membership from both the grayscale similarity between central pixels and single neighboring pixels and the spatial similarity between central pixels and neighborhood and improves effectively the convergence rate and self-adaptivity of the algorithm. Experimental results show that the proposed method can achieve more accurate segmentation of vascular adhesion, pleural adhesion, and ground glass opacity (GGO pulmonary nodules than other typical algorithms.
A Fast Channel Switching Method in EPON System for IPTV Service
Nie, Yaling; Yoshiuchi, Hideya
This paper presents a fast channel switching method in Ethernet Passive Optical Network (EPON) system for IPTV service. Fast channel switching is one of the important features of successful IPTV systems. Users surely prefer IPTV systems with small channel switching time rather than a longer one. Thus a channel switching control module and a channel/permission list in EPON system’s ONU or OLT is designed. When EPON system receives channel switching message from IPTV end user, the channel switching control module will catch the message and search the channel list and permission list maintained in EPON system, then got the matching parameter of EPON for the new channel. The new channel’s data transmission will be enabled by directly updating the optical filter of the ONU that end user connected. By using this method in EPON system, it provides a solution for dealing with channel switching delays in IPTV service.
Methods for monitoring the initial load to critical in the fast test reactor
International Nuclear Information System (INIS)
Johnson, D.L.
1975-08-01
Conventional symmetric fuel loadings for the initial loading to critical of the Fast Test Reactor (FTR) are predicted to be more time consuming than asymmetric or trisector loadings. Potentially significant time savings can be realized by the latter, since adequate intermediate assessments of neutron multiplication can be made periodically without control rod reconnection in all trisectors. Experimental simulation of both loading schemes was carried out in the Reverse Approach to Critical (RAC) experiments in the Fast Test Reactor-Engineering Mockup Critical facility. Analyses of these experiments indicated that conventional source multiplication methods can be applied for monitoring either a symmetric or asymmetric fuel loading scheme equally well provided that detection efficiency corrections are employed. Methods for refining predictions of reactivity and count rates for the stages in a load to critical were also investigated. (auth)
International Nuclear Information System (INIS)
Takeda, T.; Usami, S.; Fujimura, K.; Takakuwa, M.
2015-01-01
The Ministry of Education, Culture, Sports, Science and Technology in Japan has launched a national project entitled 'technology development for the environmental burden reduction' in 2013. The present study is one of the studies adopted as the national project. The objective of the study is the efficient and safe transmutation and volume reduction of minor actinides (MA) with long-lived radioactivity and high decay heat contained in high level radioactive wastes by using sodium cooled fast reactors. We are developing MA transmutation core concepts which harmonize efficient MA transmutation with core safety. To accurately design the core concepts we have improved calculation methods for estimating the transmutation rate of individual MA nuclides, and estimating and reducing uncertainty of MA transmutation. The overview of the present project is first described. Then the method improvement is presented with numerical results for a minor-actinide transmutation fast reactor. The analysis is based on Monju reactor data. (authors)
Energy Technology Data Exchange (ETDEWEB)
Samsahl, K
1966-02-15
An anion-exchange method based on fast selective sorption steps from mixtures of sulfuric, hydrobromic, and hydrochloric acid solutions has been developed for the separation of five different groups of radioactive trace elements in neutron-irradiated biological material. The separations are performed automatically with a simple proportioning pump apparatus. The apparatus allows the exact adjustment of influent solutions to the series of ion-exchange columns. The practical application of the method is described in detail. The successful use of the method is practically independent on the level of Na activity present in the sample.
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron
American Society for Testing and Materials. Philadelphia
2009-01-01
DESIG: E 263 09 ^TITLE: Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron ^SIGNUSE: Refer to Guide E 844 for guidance on the selection, irradiation, and quality control of neutron dosimeters. Refer to Practice E 261 for a general discussion of the determination of fast-neutron fluence rate with threshold detectors. Pure iron in the form of foil or wire is readily available and easily handled. Fig. 1 shows a plot of cross section as a function of neutron energy for the fast-neutron reaction 54Fe(n,p)54Mn (1). This figure is for illustrative purposes only to indicate the range of response of the 54Fe(n,p)54Mn reaction. Refer to Guide E 1018 for descriptions of recommended tabulated dosimetry cross sections. 54Mn has a half-life of 312.13 days (3) (2) and emits a gamma ray with an energy of 834.845 keV (5). (2) Interfering activities generated by neutron activation arising from thermal or fast neutron interactions are 2.57878 (46)-h 56Mn, 44.95-d (8) 59Fe, and 5.27...
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Niobium
American Society for Testing and Materials. Philadelphia
2008-01-01
1.1 This test method describes procedures for measuring reaction rates by the activation reaction 93Nb(n,n′)93mNb. 1.2 This activation reaction is useful for monitoring neutrons with energies above approximately 0.5 MeV and for irradiation times up to about 30 years. 1.3 With suitable techniques, fast-neutron reaction rates for neutrons with energy distribution similar to fission neutrons can be determined in fast-neutron fluences above about 1016cm−2. In the presence of high thermal-neutron fluence rates (>1012cm−2·s−1), the transmutation of 93mNb due to neutron capture should be investigated. In the presence of high-energy neutron spectra such as are associated with fusion and spallation sources, the transmutation of 93mNb by reactions such as (n,2n) may occur and should be investigated. 1.4 Procedures for other fast-neutron monitors are referenced in Practice E 261. 1.5 Fast-neutron fluence rates can be determined from the reaction rates provided that the appropriate cross section information ...
International Nuclear Information System (INIS)
Feit, M.D.; Fleck, J.A. Jr.
1989-01-01
We describe a spectral method for solving the paraxial wave equation in cylindrical geometry that is based on expansion of the exponential evolution operator in a Taylor series and use of fast Fourier transforms to evaluate derivatives. A fourth-order expansion gives excellent agreement with a two-transverse-dimensional split-operator calculation at a fraction of the cost in computation time per z step and at a considerable savings in storage
Swarm: robust and fast clustering method for amplicon-based studies
Rognes, Torbjørn; Quince, Christopher; de Vargas, Colomban; Dunthorn, Micah
2014-01-01
Popular de novo amplicon clustering methods suffer from two fundamental flaws: arbitrary global clustering thresholds, and input-order dependency induced by centroid selection. Swarm was developed to address these issues by first clustering nearly identical amplicons iteratively using a local threshold, and then by using clusters’ internal structure and amplicon abundances to refine its results. This fast, scalable, and input-order independent approach reduces the influence of clustering parameters and produces robust operational taxonomic units. PMID:25276506
International Nuclear Information System (INIS)
Dwivedi, S.R.; Jain, D.
1979-01-01
The multigroup collision probability equations were solved by the variational method to derive a simple relation between the multiplication factor and the size of a small spherical bare or reflected fast reactor. This relation was verified by a number of 26-group, S 4 , transport theory calculations in one-dimensional spherical geometry for enriched uranium and plutonium systems. It has been shown that further approximations to the above relation lead to the universal empirical relation obtained by Anil Kumar. (orig.) [de
Swarm: robust and fast clustering method for amplicon-based studies
Directory of Open Access Journals (Sweden)
Frédéric Mahé
2014-09-01
Full Text Available Popular de novo amplicon clustering methods suffer from two fundamental flaws: arbitrary global clustering thresholds, and input-order dependency induced by centroid selection. Swarm was developed to address these issues by first clustering nearly identical amplicons iteratively using a local threshold, and then by using clusters’ internal structure and amplicon abundances to refine its results. This fast, scalable, and input-order independent approach reduces the influence of clustering parameters and produces robust operational taxonomic units.
Fast and Sensitive Method for Determination of Domoic Acid in Mussel Tissue
Directory of Open Access Journals (Sweden)
Elena Barbaro
2016-01-01
Full Text Available Domoic acid (DA, a neurotoxic amino acid produced by diatoms, is the main cause of amnesic shellfish poisoning (ASP. In this work, we propose a very simple and fast analytical method to determine DA in mussel tissue. The method consists of two consecutive extractions and requires no purification steps, due to a reduction of the extraction of the interfering species and the application of very sensitive and selective HILIC-MS/MS method. The procedural method was validated through the estimation of trueness, extract yield, precision, detection, and quantification limits of analytical method. The sample preparation was also evaluated through qualitative and quantitative evaluations of the matrix effect. These evaluations were conducted both on the DA-free matrix spiked with known DA concentration and on the reference certified material (RCM. We developed a very selective LC-MS/MS method with a very low value of method detection limit (9 ng g−1 without cleanup steps.
A fast and automatic mosaic method for high-resolution satellite images
Chen, Hongshun; He, Hui; Xiao, Hongyu; Huang, Jing
2015-12-01
We proposed a fast and fully automatic mosaic method for high-resolution satellite images. First, the overlapped rectangle is computed according to geographical locations of the reference and mosaic images and feature points on both the reference and mosaic images are extracted by a scale-invariant feature transform (SIFT) algorithm only from the overlapped region. Then, the RANSAC method is used to match feature points of both images. Finally, the two images are fused into a seamlessly panoramic image by the simple linear weighted fusion method or other method. The proposed method is implemented in C++ language based on OpenCV and GDAL, and tested by Worldview-2 multispectral images with a spatial resolution of 2 meters. Results show that the proposed method can detect feature points efficiently and mosaic images automatically.
A fast dose calculation method based on table lookup for IMRT optimization
International Nuclear Information System (INIS)
Wu Qiuwen; Djajaputra, David; Lauterbach, Marc; Wu Yan; Mohan, Radhe
2003-01-01
This note describes a fast dose calculation method that can be used to speed up the optimization process in intensity-modulated radiotherapy (IMRT). Most iterative optimization algorithms in IMRT require a large number of dose calculations to achieve convergence and therefore the total amount of time needed for the IMRT planning can be substantially reduced by using a faster dose calculation method. The method that is described in this note relies on an accurate dose calculation engine that is used to calculate an approximate dose kernel for each beam used in the treatment plan. Once the kernel is computed and saved, subsequent dose calculations can be done rapidly by looking up this kernel. Inaccuracies due to the approximate nature of the kernel in this method can be reduced by performing scheduled kernel updates. This fast dose calculation method can be performed more than two orders of magnitude faster than the typical superposition/convolution methods and therefore is suitable for applications in which speed is critical, e.g., in an IMRT optimization that requires a simulated annealing optimization algorithm or in a practical IMRT beam-angle optimization system. (note)
Methods for reactor physics calculations for control rods in fast reactors
International Nuclear Information System (INIS)
Grimstone, M.J.; Rowlands, J.L.
1988-12-01
The IAEA Specialists' Meeting on ''Methods for Reactor Physics Calculations for Control Rods in Fast Reactors'' was held in Winfrith, United Kingdom, on 6-8 December, 1988. The meeting was attended by 23 participants from nine countries. The purpose of the meeting was to review the current calculational methods and their accuracy as assessed by theoretical studies and comparisons with measurements, and then to identify the requirements for improved methods or additional studies and comparisons. The control rod properties or effects to be considered were their reactivity worths, their effect on the power distribution through the core, and the reaction rates and energy deposition both within and adjacent to the rods. The meeting was divided into five sessions, in the first of which each national delegation presented a brief overview of their programme of work on calculational methods for fast reactor control rods. In the next three sessions a total of seventeen papers were presented describing calculational methods and assessments of their accuracy. The final session was a discussion to draw conclusions regarding the current status of methods and the further developments and validation work required. A separate abstract was prepared for each of the 23 papers presented at the meeting. Refs, figs and tabs
Nonuniform fast Fourier transform method for numerical diffraction simulation on tilted planes.
Xiao, Yu; Tang, Xiahui; Qin, Yingxiong; Peng, Hao; Wang, Wei; Zhong, Lijing
2016-10-01
The method, based on the rotation of the angular spectrum in the frequency domain, is generally used for the diffraction simulation between the tilted planes. Due to the rotation of the angular spectrum, the interval between the sampling points in the Fourier domain is not even. For the conventional fast Fourier transform (FFT)-based methods, a spectrum interpolation is needed to get the approximate sampling value on the equidistant sampling points. However, due to the numerical error caused by the spectrum interpolation, the calculation accuracy degrades very quickly as the rotation angle increases. Here, the diffraction propagation between the tilted planes is transformed into a problem about the discrete Fourier transform on the uneven sampling points, which can be evaluated effectively and precisely through the nonuniform fast Fourier transform method (NUFFT). The most important advantage of this method is that the conventional spectrum interpolation is avoided and the high calculation accuracy can be guaranteed for different rotation angles, even when the rotation angle is close to π/2. Also, its calculation efficiency is comparable with that of the conventional FFT-based methods. Numerical examples as well as a discussion about the calculation accuracy and the sampling method are presented.
International Nuclear Information System (INIS)
Schmid, E.
1987-03-01
Today important chemical substances like proteins can be produced easily and in large amounts. The primary structure of proteins can be analysed automatically, however the procedure can take some months of time. A novel method, fast atom bombardment mass spectrometry (FAB-MS) in combination with enzymatic degradation not only decreases the analysis time, but gives also additional information about the primary structure. Especially for the verification of protein structures - which is important for recombinant proteins - FAB-MS is a very useful method. 40 refs., 56 figs. (P.W.)
A time-dependent semiclassical wavepacket method using a fast Fourier transform (FFT) algorithm
International Nuclear Information System (INIS)
Gauss, J.; Heller, E.J.
1991-01-01
A new semiclassical propagator based on a local expansion of the potential up to second order around the moving center of the wavepackt is proposed. Formulas for the propagator are derived and the implementation using grid and fast Fourier transform (FFT) methods is discussed. The semiclassical propagator can be improved up to the exact quantum mechanical limit by including anharmonic corrections using a split operator approach. Preliminary applications to the CH 3 I photodissociation problem show the applicability and accuracy of the proposed method. (orig.)D
The effect of the neutron spectra unfolding method on the fast neutron dose determination
International Nuclear Information System (INIS)
Marinkovic, P.; Zavaljevski, N.
1992-01-01
Based on Shanon's information theory, a new unfolding method which gives non-negative spectrum values and a relatively low variance, is proposed, and a numerical code suitable for application in fast neutron spectroscopy based on proton recoil is developed. The principles of maximum entropy and maximum likelihood are jointly applied. According to the principle of maximum likelihood, the distribution functions around the mean value of the counts in the MCA channels are assumed to be Gaussians. The Lagrange parameter method is applied in the search for an optimal non-negative solution. The nonlinear system of equations is solved using the gradient and Newton iterative algorithms. (orig.)
International Nuclear Information System (INIS)
Abashin, E.G.; Lisovskij, I.P.; Smakhtin, L.A.
1980-01-01
A neutron-activation method is suggested for determination of fluorine in fodder phosphates and phosphorite flour. Used as the source of fast neutrons was an NG-150M neutron generator with a maximum yield of 10 8 nxcm -2 xs -1 . Samples were irradiated in polyethylene ampoules using a pneumatic shuttle. Fluorine was determined with reference to the fluorine-18 isotope. The accuracy of determining fluorine in fodder phosphates and phosphorite flour is 1 to 4% (rel.) at a rate of not less than 10 samples per hour. The method is suitable for in-process testing of products
International Nuclear Information System (INIS)
Samsahl, K.
1964-12-01
A method has been developed for the determination with neutron-activation analysis of the following trace elements in soft biological tissues: Br, Ca, Cl, Cu, K, Mg, Mn, Mo, Na, P, Sr and Zn. The method consists in performing a short-term irradiation of the samples with a high thermal neutron flux, followed by fast chemical separations and gamma-spectrometric measurements. The chemical separations and the measurements of short-lived nuclides from a run are finished within 70 min, after the end of irradiation
Fast method of NMR imaging based on trains of spin echoes
International Nuclear Information System (INIS)
Hennel, F.
1993-01-01
A theoretical introduction to Fourier NMR imaging and a discussion of fast methods are presented. Then an application of the method of echo-planar imaging (EPI) with spin echoes in a micro-imaging system is described together with introduced modifications of the sequence. A new technique for the measurement of flow profiles in liquids which results from a modification of x-pulsed EPI is presented. The development of new software for a NMR micro-imaging system is described, too. 51 refs, 29 refs
Energy Technology Data Exchange (ETDEWEB)
Samsahl, K
1964-12-15
A method has been developed for the determination with neutron-activation analysis of the following trace elements in soft biological tissues: Br, Ca, Cl, Cu, K, Mg, Mn, Mo, Na, P, Sr and Zn. The method consists in performing a short-term irradiation of the samples with a high thermal neutron flux, followed by fast chemical separations and gamma-spectrometric measurements. The chemical separations and the measurements of short-lived nuclides from a run are finished within 70 min, after the end of irradiation.
Energy Technology Data Exchange (ETDEWEB)
Abashin, E G; Lisovskii, I P; Smakhtin, L A
1980-01-01
A neutron-activation method is suggested for determination of fluorine in fodder phosphates and phosphorite flour. Used as the source of fast neutrons was an NG-150M neutron generator with a maximum yield of 10/sup 8/ nxcm/sup -2/xs/sup -1/. Samples were irradiated in polyethylene ampoules using a pneumatic shuttle. Fluorine was determined with reference to the fluorine-18 isotope. The accuracy of determining fluorine in fodder phosphates and phosphorite flour is 1 to 4% (rel.) at a rate of not less than 10 samples per hour. The method is suitable for in-process testing of products.
The effect of the neutron spectra unfolding method on the fast neutron dose determination
International Nuclear Information System (INIS)
Marinkovic, P.; Avdic, S.; Pesic, M.; Zavaljevski, N
1992-09-01
Based on Shanon's information theory, a new unfolding method which gives non-negative spectrum values and a relatively low variance, is proposed, and a numerical code suitable for application in fast neutron spectroscopy based on proton recoil is developed. The principles of maximum entropy and maximum likelihood are jointly applied. According to the principle of maximum likelihood, the distribution functions around the mean value of the counts in the MCA channels are assumed to be Gaussians. The Lagrange parameter method is applied in the search for an optimal non-negative solution. The nonlinear system of equations is solved using the gradient and Newton iterative algorithms. (author)
Absolute calibration method for fast-streaked, fiber optic light collection, spectroscopy systems
International Nuclear Information System (INIS)
Johnston, Mark D.; Frogget, Brent; Oliver, Bryan Velten; Maron, Yitzhak; Droemer, Darryl W.; Crain, Marlon D.
2010-01-01
This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.
Periodic boundary conditions and the error-controlled fast multipole method
Energy Technology Data Exchange (ETDEWEB)
Kabadshow, Ivo
2012-08-22
The simulation of pairwise interactions in huge particle ensembles is a vital issue in scientific research. Especially the calculation of long-range interactions poses limitations to the system size, since these interactions scale quadratically with the number of particles. Fast summation techniques like the Fast Multipole Method (FMM) can help to reduce the complexity to O(N). This work extends the possible range of applications of the FMM to periodic systems in one, two and three dimensions with one unique approach. Together with a tight error control, this contribution enables the simulation of periodic particle systems for different applications without the need to know and tune the FMM specific parameters. The implemented error control scheme automatically optimizes the parameters to obtain an approximation for the minimal runtime for a given energy error bound.
Fast Bound Methods for Large Scale Simulation with Application for Engineering Optimization
Patera, Anthony T.; Peraire, Jaime; Zang, Thomas A. (Technical Monitor)
2002-01-01
In this work, we have focused on fast bound methods for large scale simulation with application for engineering optimization. The emphasis is on the development of techniques that provide both very fast turnaround and a certificate of Fidelity; these attributes ensure that the results are indeed relevant to - and trustworthy within - the engineering context. The bound methodology which underlies this work has many different instantiations: finite element approximation; iterative solution techniques; and reduced-basis (parameter) approximation. In this grant we have, in fact, treated all three, but most of our effort has been concentrated on the first and third. We describe these below briefly - but with a pointer to an Appendix which describes, in some detail, the current "state of the art."
Comparison of the methods of seismic analysis applicable to fast reactors in the EEC countries
International Nuclear Information System (INIS)
Defalque, M.; Kunsch, P.; Preumont, A.
1986-01-01
The countries in the Community which are concerned by this study are those currently involved in the operation or development of fast reactors, namely: FRANCE (Phenix - Superphenix), FRG - BELGIUM - THE NETHERLANDS associated within DeBeNe (SNR - 300), UNITED KINGDOM (UK) (PFR-CDFR), ITALY (PEC). The first aim of the study is to enumerate the common points and differences in the national rules and regulations for the seismic analysis of fast breeder reactors. Such divergences may be encountered at different design stages, namely: in the definition of the seismic input data, in the choice of design limits and in the degree of conservatism applied to the calculation methods employed. For every one of these three stages, it is necessary to identify the points likely to influence the results of the analysis and consequently the over-all safety margin with regard to the event concerned. 73 refs
Ghaziani, Amin; Baldassarri, Delia
2013-01-01
Social scientists describe culture as either coherent or incoherent and political dissent as either unifying or divisive. This article moves beyond such dichotomies. Content, historical, and network analyses of public debates on how to organize four lesbian, gay, bisexual, and transgender (LGBT) Washington marches provide evidence for an integrative position. Rather than just describe consistencies or contradictions, we contend that the key analytic challenge is to explain the organization of differences. We propose one way of doing this using the mechanism of a cultural anchor. Within and across marches, a small collection of ideas remains fixed in the national conversation, yet in a way that allows activists to address their internal diversity and respond to unfolding historical events. These results suggest that activists do not simply organize around their similarities but, through cultural anchors, they use their commonalities to build a thinly coherent foundation that can also support their differences. Situated at the nexus of culture, social movements, sexualities, and networks, this article demonstrates how the anchoring mechanism works in the context of LGBT political organizing. PMID:23661809
Fast beam cut-off method in RF-knockout extraction for spot-scanning
Furukawa, T
2002-01-01
An irradiation method with magnetic scanning has been developed in order to provide accurate irradiation even for an irregular target shape. The scanning method has strongly required a lower ripple of the beam spill and a faster response to beam-on/off in slow extraction from a synchrotron ring. At HIMAC, RF-knockout extraction has utilized a bunched beam to reduce the beam-spill ripple. Therefore, particles near the resonance can be spilled out from the separatrices by synchrotron oscillation as well as by a transverse RF field. From this point of view, a fast beam cut-off method has been proposed and verified by both simulations and experiments. The maximum delay from the beam cut-off signal to beam-off has been improved to around 60 mu s from 700 mu s by a usual method. Unwanted dose has been considerably reduced by around a factor of 10 compared with that by the usual method.
A fast point-cloud computing method based on spatial symmetry of Fresnel field
Wang, Xiangxiang; Zhang, Kai; Shen, Chuan; Zhu, Wenliang; Wei, Sui
2017-10-01
Aiming at the great challenge for Computer Generated Hologram (CGH) duo to the production of high spatial-bandwidth product (SBP) is required in the real-time holographic video display systems. The paper is based on point-cloud method and it takes advantage of the propagating reversibility of Fresnel diffraction in the propagating direction and the fringe pattern of a point source, known as Gabor zone plate has spatial symmetry, so it can be used as a basis for fast calculation of diffraction field in CGH. A fast Fresnel CGH method based on the novel look-up table (N-LUT) method is proposed, the principle fringe patterns (PFPs) at the virtual plane is pre-calculated by the acceleration algorithm and be stored. Secondly, the Fresnel diffraction fringe pattern at dummy plane can be obtained. Finally, the Fresnel propagation from dummy plan to hologram plane. The simulation experiments and optical experiments based on Liquid Crystal On Silicon (LCOS) is setup to demonstrate the validity of the proposed method under the premise of ensuring the quality of 3D reconstruction the method proposed in the paper can be applied to shorten the computational time and improve computational efficiency.
Energy Technology Data Exchange (ETDEWEB)
Jacquet, P.
2011-05-23
Due to safety rules running on fourth generation reactors' core development, neutronics simulation tools have to be as accurate as never before. First part of this report enumerates every step of fast reactor's neutronics simulation implemented in current reference code: ECCO. Considering the field of fast reactors that meet criteria of fourth generation, ability of models to describe self-shielding phenomenon, to simulate neutrons leakage in a lattice of fuel assemblies and to produce representative macroscopic sections is evaluated. The second part of this thesis is dedicated to the simulation of fast reactors' core with steel reflector. These require the development of advanced methods of condensation and homogenization. Several methods are proposed and compared on a typical case: the ZONA2B core of MASURCA reactor. (author) [French] Les criteres de surete qui regissent le developpement de coeurs de reacteurs de quatrieme generation implique l'usage d'outils de calcul neutronique performants. Une premiere partie de la these reprend toutes les etapes de modelisation neutronique des reacteurs rapides actuellement d'usage dans le code de reference ECCO. La capacite des modeles a decrire le phenomene d'autoprotection, a representer les fuites neutroniques au niveau d'un reseau d'assemblages combustibles et a generer des sections macroscopiques representatives est appreciee sur le domaine des reacteurs rapides innovants respectant les criteres de quatrieme generation. La deuxieme partie de ce memoire se consacre a la modelisation des coeurs rapides avec reflecteur acier. Ces derniers necessitent le developpement de methodes avancees de condensation et d'homogenisation. Plusieurs methodes sont proposees et confrontees sur un probleme de modelisation typique: le coeur ZONA2B du reacteur maquette MASURCA
Method and apparatus for dual-spaced fast/epithermal neutron porosity measurements
International Nuclear Information System (INIS)
Smith, H.D. Jr.
1986-01-01
A method is described for determining the porosity of earth formations in the vicinity of a well borehole, comprising: (a) irradiating the earth formations in the vicinity of the well borehole with a continuous chemical type source of fast neutrons, (b) detecting the fast neutron population at a first shorter spaced distance from the neutron source in the borehole and generating signals representative thereof, (c) detecting the epithermal neutron population at a second space distance from the neutron source in the borehole and generating signals representative thereof, the second spaced distance being greater than the first spaced distance from the neutron source, (d) forming a ratio of the signals representing the fast and epithermal neutron populations to derive a measurement signal functionally related to the porosity of the earth formations in the vicinity of the borehole, and (e) calibrating the measurement signal according to a predetermined functional relationship to derive a porosity signal quantitatively representative of the porosity of the earth formations in the vicinity of the borehole
A Fast Calculation Method for Analyzing the Effect of Wind Generation on ATC
Directory of Open Access Journals (Sweden)
M.A Armin
2015-12-01
Full Text Available Wind energy penetration in power system has been increased very fast and large amount of capitals invested for wind farms all around the world. Meanwhile, in power systems with wind turbine generators (WTGs, the value of Available transfer capability (ATC is influenced by the probabilistic nature of the wind power. The Mont Carlo Simulation (MCS is the most common method to model the uncertainty of WTG. However, the MCS method suffers from low convergence rate. To overcome this shortcoming, the proposed technique in this paper uses a new formulation for solving ATC problem analytically. This lowers the computational burden of the ATC computation and hence results in increased convergence rate of the MCS. Using this fast technique to evaluate the ATC, wind generation and load correlation is required to get into modeling. A numerical method is presented to consider load and wind correlation. The proposed method is tested on the modified IEEE 118 bus to analyze the impacts of the WTGs on the ATC. The obtained results show that wind generation capacity and its correlation with system load has significant impacts on the network transfer capability. In other words, ATC probability distribution is sensitive to the wind generation capacity.
Prosthetic component segmentation with blur compensation: a fast method for 3D fluoroscopy.
Tarroni, Giacomo; Tersi, Luca; Corsi, Cristiana; Stagni, Rita
2012-06-01
A new method for prosthetic component segmentation from fluoroscopic images is presented. The hybrid approach we propose combines diffusion filtering, region growing and level-set techniques without exploiting any a priori knowledge of the analyzed geometry. The method was evaluated on a synthetic dataset including 270 images of knee and hip prosthesis merged to real fluoroscopic data simulating different conditions of blurring and illumination gradient. The performance of the method was assessed by comparing estimated contours to references using different metrics. Results showed that the segmentation procedure is fast, accurate, independent on the operator as well as on the specific geometrical characteristics of the prosthetic component, and able to compensate for amount of blurring and illumination gradient. Importantly, the method allows a strong reduction of required user interaction time when compared to traditional segmentation techniques. Its effectiveness and robustness in different image conditions, together with simplicity and fast implementation, make this prosthetic component segmentation procedure promising and suitable for multiple clinical applications including assessment of in vivo joint kinematics in a variety of cases.
Utilization of OR method toward realization of better fast breeder reactor cycle
International Nuclear Information System (INIS)
Shiotani, Hiroki
2008-01-01
Fast Reactor Cycle Technology Development (FaCT) Project was now started aiming at commercialization of new nuclear power plants system. In parallel with development of component technology and technology demonstration by test, development of comprehensive evaluation method of the FBR cycle system is under way and scenario study, discounted cash flow (DCF) method, analytic hierarchy process (AHP), real option, supply chain management (SCM) and others are used. Since commercialized FBR cycle would request long-term and large-scale development contributed by so many participants, modeling of nuclear system and knowledge management are beneficial even for development of evaluation method and further utilization of OR technology is highly expected. Comprehensive evaluation methods now utilized or developing were overlooked from the standpoint of OR, 'Science of Better'. (T. Tanaka)
Fall, Mandiaye; Boutami, Salim; Glière, Alain; Stout, Brian; Hazart, Jerome
2013-06-01
A combination of the multilevel fast multipole method (MLFMM) and boundary element method (BEM) can solve large scale photonics problems of arbitrary geometry. Here, MLFMM-BEM algorithm based on a scalar and vector potential formulation, instead of the more conventional electric and magnetic field formulations, is described. The method can deal with multiple lossy or lossless dielectric objects of arbitrary geometry, be they nested, in contact, or dispersed. Several examples are used to demonstrate that this method is able to efficiently handle 3D photonic scatterers involving large numbers of unknowns. Absorption, scattering, and extinction efficiencies of gold nanoparticle spheres, calculated by the MLFMM, are compared with Mie's theory. MLFMM calculations of the bistatic radar cross section (RCS) of a gold sphere near the plasmon resonance and of a silica coated gold sphere are also compared with Mie theory predictions. Finally, the bistatic RCS of a nanoparticle gold-silver heterodimer calculated with MLFMM is compared with unmodified BEM calculations.
Fast multiview three-dimensional reconstruction method using cost volume filtering
Lee, Seung Joo; Park, Min Ki; Jang, In Yeop; Lee, Kwan H.
2014-03-01
As the number of customers who want to record three-dimensional (3-D) information using a mobile electronic device increases, it becomes more and more important to develop a method which quickly reconstructs a 3-D model from multiview images. A fast multiview-based 3-D reconstruction method is presented, which is suitable for the mobile environment by constructing a cost volume of the 3-D height field. This method consists of two steps: the construction of a reliable base surface and the recovery of shape details. In each step, the cost volume is constructed using photoconsistency and then it is filtered according to the multiscale. The multiscale-based cost volume filtering allows the 3-D reconstruction to maintain the overall shape and to preserve the shape details. We demonstrate the strength of the proposed method in terms of computation time, accuracy, and unconstrained acquisition environment.
A fast and efficient method for sequential cone-beam tomography
International Nuclear Information System (INIS)
Koehler, Th.; Proksa, R.; Grass, M.
2001-01-01
Sequential cone-beam tomography is a method that uses data of two or more parallel circular trajectories of a cone-beam scanner to reconstruct the object function. We propose a condition for the data acquisition that ensures that all object points between two successive circles are irradiated over an angular span of the x-ray source position of exactly 360 deg. in total as seen along the rotation axis. A fast and efficient approximative reconstruction method for the proposed acquisition is presented which uses data from exactly 360 deg. for every object point. It is based on the Tent-FDK method which was recently developed for single circular cone-beam CT. The measurement geometry does not provide sufficient data for exact reconstruction but it is shown that the proposed reconstruction method provides satisfying image quality for small cone angles
Fast method for geometric calibration of detectors and matching testing between two detectors
International Nuclear Information System (INIS)
Pechenova, O.Yu.
2002-01-01
A fast method of geometric calibration of detectors has been proposed. The main idea of this method is to determine offsets by fitting the real data distribution by analytic functions which describe the motion of one detector relative to the other one. This method can be applicable to offsets determination for one detector relative to the other detector or for one part of the detector relative to its other part. The detectors should be placed perpendicular to the beam axis. The form of analytic functions depends on the geometry of the experiment and direction of the coordinate axes. The analytic functions have been obtained using the rotation matrices. This method can be applied to the matching testing between two detectors
International Nuclear Information System (INIS)
Zhan, Shuyue; Wang, Xiaoping; Liu, Yuling
2011-01-01
To simplify the algorithm for determining the surface plasmon resonance (SPR) angle for special applications and development trends, a fast method for determining an SPR angle, called the fixed-boundary centroid algorithm, has been proposed. Two experiments were conducted to compare three centroid algorithms from the aspects of the operation time, sensitivity to shot noise, signal-to-noise ratio (SNR), resolution, and measurement range. Although the measurement range of this method was narrower, the other performance indices were all better than the other two centroid methods. This method has outstanding performance, high speed, good conformity, low error and a high SNR and resolution. It thus has the potential to be widely adopted
International Nuclear Information System (INIS)
Nakata, Noboru; Fukutomi, Yasuo
1998-01-01
To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using 14 C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO 2 was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)
Energy Technology Data Exchange (ETDEWEB)
Nakata, Noboru; Fukutomi, Yasuo [National Inst. of Infectious Deseases, Tokyo (Japan)
1998-02-01
To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using {sup 14}C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO{sub 2} was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)
A fast numerical method for the valuation of American lookback put options
Song, Haiming; Zhang, Qi; Zhang, Ran
2015-10-01
A fast and efficient numerical method is proposed and analyzed for the valuation of American lookback options. American lookback option pricing problem is essentially a two-dimensional unbounded nonlinear parabolic problem. We reformulate it into a two-dimensional parabolic linear complementary problem (LCP) on an unbounded domain. The numeraire transformation and domain truncation technique are employed to convert the two-dimensional unbounded LCP into a one-dimensional bounded one. Furthermore, the variational inequality (VI) form corresponding to the one-dimensional bounded LCP is obtained skillfully by some discussions. The resulting bounded VI is discretized by a finite element method. Meanwhile, the stability of the semi-discrete solution and the symmetric positive definiteness of the full-discrete matrix are established for the bounded VI. The discretized VI related to options is solved by a projection and contraction method. Numerical experiments are conducted to test the performance of the proposed method.
Directory of Open Access Journals (Sweden)
Annam Vamseedhar
2009-07-01
Full Text Available Objectives: To improve the smear microscopy for detection of acid-fast bacilli (AFB in fine needle aspiration cytology (FNAC of lymph node using the bleach method and also to compare this with cytological diagnosis and the conventional Ziehl-Neelsen (ZN method. Study Design: In 99 consecutive patients with clinical suspicion of tuberculosis (TB presenting with lymphadenopathy, FNACs were performed. Smears from the aspirates were processed for routine cytology and the conventional ZN method. The remaining material in the needle hub and/or the syringe was used for the bleach method. The significance of the bleach method over the conventional ZN method and cytology was analyzed using the χ2 test. Results: Of 99 aspirates, 93 were studied and the remaining six were excluded from the study due to diagnosis of malignancy in 4.04% (4/6 and inadequate aspiration in 2.02% (2/6. Among the 93 aspirates, 33.33% (31/93 were positive for AFB on conventional ZN method, 41.94% (39/93 were indicative of TB on cytology and the smear positivity increased to 63.44% (59/93 on bleach method. Conclusion: The bleach method is simple, inexpensive and potent disinfectant, also limiting the risk of laboratory-acquired infections. The implementation of the bleach method clearly improves microscopic detection and can be a useful contribution to routine cytology.
International Nuclear Information System (INIS)
Faucher, V.
2014-01-01
This HDR is dedicated to the research in the framework of fast transient dynamics for industrial fluid-structure systems carried in the Laboratory of Dynamic Studies from CEA, implementing new numerical methods for the modelling of complex systems and the parallel solution of large coupled problems on supercomputers. One key issue for the proposed approaches is the limitation to its minimum of the number of non-physical parameters, to cope with constraints arising from the area of usage of the concepts: safety for both nuclear applications (CEA, EDF) and aeronautics (ONERA), protection of the citizen (EC/JRC) in particular. Kinematic constraints strongly coupling structures (namely through unilateral contact) or fluid and structures (with both conformant or non-conformant meshes depending on the geometrical situation) are handled through exact methods including Lagrange Multipliers, with consequences on the solution strategy to be dealt with. This latter aspect makes EPX, the simulation code where the methods are integrated, a singular tool in the community of fast transient dynamics software. The document mainly relies on a description of the modelling needs for industrial fast transient scenarios, for nuclear applications in particular, and the proposed solutions built in the framework of the collaboration between CEA, EDF (via the LaMSID laboratory) and the LaMCoS laboratory from INSA Lyon. The main considered examples are the tearing of the fluid-filled tank after impact, the Code Disruptive Accident for a Generation IV reactor or the ruin of reinforced concrete structures under impact. Innovative models and parallel algorithms are thus proposed, allowing to carry out with robustness and performance the corresponding simulations on supercomputers made of interconnected multi-core nodes, with a strict preservation of the quality of the physical solution. This was particularly the main point of the ANR RePDyn project (2010-2013), with CEA as the pilot. (author
Recent development of radioanalytical method at IBR-2 pulsed fast reactor of the JINR
International Nuclear Information System (INIS)
Nazarov, V.M.; Pavlov, S.S.; Herrera, E.
1991-01-01
The experience of the use of radioanalytical methods, including NAA at IBR-2 pilsed fast reactor of the JINR, is discussed. Physical and technical parameters of the experimental installation designed for NAA and radiography are given. The detailed examples of the application of resonance neutrons to the control of the environment in the geology of oil, in multi-element analysis of food products and superpure materials as well as in nuclear physics are reviewed. The works on the application of the neutron isotopes sources for express determination of nitrogen content in original and synthetic materials are introduced. 7 refs.; 8 figs.; 3 tabs
Palmesi, P.; Exl, L.; Bruckner, F.; Abert, C.; Suess, D.
2017-11-01
The long-range magnetic field is the most time-consuming part in micromagnetic simulations. Computational improvements can relieve problems related to this bottleneck. This work presents an efficient implementation of the Fast Multipole Method [FMM] for the magnetic scalar potential as used in micromagnetics. The novelty lies in extending FMM to linearly magnetized tetrahedral sources making it interesting also for other areas of computational physics. We treat the near field directly and in use (exact) numerical integration on the multipole expansion in the far field. This approach tackles important issues like the vectorial and continuous nature of the magnetic field. By using FMM the calculations scale linearly in time and memory.
Adaptive grouping for the higher-order multilevel fast multipole method
DEFF Research Database (Denmark)
Borries, Oscar Peter; Jørgensen, Erik; Meincke, Peter
2014-01-01
An alternative parameter-free adaptive approach for the grouping of the basis function patterns in the multilevel fast multipole method is presented, yielding significant memory savings compared to the traditional Octree grouping for most discretizations, particularly when using higher-order basis...... functions. Results from both a uniformly and nonuniformly meshed scatterer are presented, showing how the technique is worthwhile even for regular meshes, and demonstrating that there is no loss of accuracy in spite of the large reduction in memory requirements and the relatively low computational cost....
A fast learning method for large scale and multi-class samples of SVM
Fan, Yu; Guo, Huiming
2017-06-01
A multi-class classification SVM(Support Vector Machine) fast learning method based on binary tree is presented to solve its low learning efficiency when SVM processing large scale multi-class samples. This paper adopts bottom-up method to set up binary tree hierarchy structure, according to achieved hierarchy structure, sub-classifier learns from corresponding samples of each node. During the learning, several class clusters are generated after the first clustering of the training samples. Firstly, central points are extracted from those class clusters which just have one type of samples. For those which have two types of samples, cluster numbers of their positive and negative samples are set respectively according to their mixture degree, secondary clustering undertaken afterwards, after which, central points are extracted from achieved sub-class clusters. By learning from the reduced samples formed by the integration of extracted central points above, sub-classifiers are obtained. Simulation experiment shows that, this fast learning method, which is based on multi-level clustering, can guarantee higher classification accuracy, greatly reduce sample numbers and effectively improve learning efficiency.
Energy Technology Data Exchange (ETDEWEB)
Hu, Rui, E-mail: rhu@anl.gov; Yu, Yiqi
2016-11-15
Highlights: • Developed a computationally efficient method for full-core conjugate heat transfer modeling of sodium fast reactors. • Applied fully-coupled JFNK solution scheme to avoid the operator-splitting errors. • The accuracy and efficiency of the method is confirmed with a 7-assembly test problem. • The effects of different spatial discretization schemes are investigated and compared to the RANS-based CFD simulations. - Abstract: For efficient and accurate temperature predictions of sodium fast reactor structures, a 3-D full-core conjugate heat transfer modeling capability is developed for an advanced system analysis tool, SAM. The hexagon lattice core is modeled with 1-D parallel channels representing the subassembly flow, and 2-D duct walls and inter-assembly gaps. The six sides of the hexagon duct wall and near-wall coolant region are modeled separately to account for different temperatures and heat transfer between coolant flow and each side of the duct wall. The Jacobian Free Newton Krylov (JFNK) solution method is applied to solve the fluid and solid field simultaneously in a fully coupled fashion. The 3-D full-core conjugate heat transfer modeling capability in SAM has been demonstrated by a verification test problem with 7 fuel assemblies in a hexagon lattice layout. Additionally, the SAM simulation results are compared with RANS-based CFD simulations. Very good agreements have been achieved between the results of the two approaches.
An assessment of methods of calculating sodium voiding reactivity in plutonium fuelled fast reactors
International Nuclear Information System (INIS)
Butland, A.T.D.; Simmons, W.N.; Stevenson, J.M.
1979-01-01
After a survey of the requirements an assessment of the accuracy of calculations of the sodium void effect using UK methods and data is made on the basis of the following work. First, the analysis of small and large sodium voids in the MOZART and Zebra 13 small (300 MW(E)) fast reactor mock-ups and the BIZET large fast reactor mock-ups, all of conventional design. The analysis was carried out using the UK FGL5 fine group nuclear data library, the MURAL cell code, whole reactor diffusion theory calculations of the neutron flux and perturbation theory methods. Exact perturbation theory was used in many cases, otherwise first order perturbation theory calculations were adjusted to give results equivalent to exact perturbation theory. Second, theoretical studies of some effects, including, the effects of extrapolating to fuel operating temperatures, fuel cycle and burn-up effects, and the heterogeneity effects of large fuelled subassemblies in pin geometry. Third, theoretical studies of approximations in the calculational methods including, the importance in the whole reactor calculation of the energy group structure and the spatial mesh, the importance of reactor material boundaries in the calculation of resonance shielding effects, and the use of neutron fluxes calculated using neutron diffusion theory rather than transport theory. (U.K.)
Optimization in radiotherapy treatment planning thanks to a fast dose calculation method
International Nuclear Information System (INIS)
Yang, Mingchao
2014-01-01
This thesis deals with the radiotherapy treatments planning issue which need a fast and reliable treatment planning system (TPS). The TPS is composed of a dose calculation algorithm and an optimization method. The objective is to design a plan to deliver the dose to the tumor while preserving the surrounding healthy and sensitive tissues. The treatment planning aims to determine the best suited radiation parameters for each patient's treatment. In this thesis, the parameters of treatment with IMRT (Intensity modulated radiation therapy) are the beam angle and the beam intensity. The objective function is multi-criteria with linear constraints. The main objective of this thesis is to demonstrate the feasibility of a treatment planning optimization method based on a fast dose-calculation technique developed by (Blanpain, 2009). This technique proposes to compute the dose by segmenting the patient's phantom into homogeneous meshes. The dose computation is divided into two steps. The first step impacts the meshes: projections and weights are set according to physical and geometrical criteria. The second step impacts the voxels: the dose is computed by evaluating the functions previously associated to their mesh. A reformulation of this technique makes possible to solve the optimization problem by the gradient descent algorithm. The main advantage of this method is that the beam angle parameters could be optimized continuously in 3 dimensions. The obtained results in this thesis offer many opportunities in the field of radiotherapy treatment planning optimization. (author) [fr
Directory of Open Access Journals (Sweden)
A. D. Chernyshov
2017-01-01
Full Text Available The brief presentation of the method of fast expansions is given to solve nonlinear differential equations. Application rules of the operator of fast expansions are specified for solving differential equations. According to the method of fast expansions, an unknown function can be represented as the sum of the boundary function and Fourier series sines and cosines for one variable. The special construction of the boundary functions leads to reasonably fast convergence of the Fourier series, so that for engineering calculations, it is sufficient to consider only the first three members. The method is applicable both to linear and nonlinear integro-differential systems. By means of applying the method of fast expansions to nonlinear Navier-Stokes equations the problem is reduced to a closed system of ordinary differential equations, which solution doesn't represent special difficulties. We can reapply the method of fast expansions to the resulting system of differential equations and reduce the original problem to a system of algebraic equations. If the problem is n-dimensional, then after n-fold application of the method of fast expansions the problem will be reduced to a closed algebraic system. Finally, we obtain an analytic-form solution of complicated boundary value problem in partial derivatives. The flow of an incompressible viscous fluid of Navier–Stokes is considered in a curvilinear pipe. The problem is reduced to solving a closed system of ordinary differential equations with boundary conditions by the method of fast expansions. The article considers peculiarities of finding the coefficients of boundary functions and Fourier coefficients for the zero-order and first-order operators of fast expansions. Obtaining the analytic-form solution is of great interest, because it allows to analyze and to investigate the influence of various factors on the properties of the viscous fluid in specific cases.
A Fast Gradient Method for Nonnegative Sparse Regression With Self-Dictionary
Gillis, Nicolas; Luce, Robert
2018-01-01
A nonnegative matrix factorization (NMF) can be computed efficiently under the separability assumption, which asserts that all the columns of the given input data matrix belong to the cone generated by a (small) subset of them. The provably most robust methods to identify these conic basis columns are based on nonnegative sparse regression and self dictionaries, and require the solution of large-scale convex optimization problems. In this paper we study a particular nonnegative sparse regression model with self dictionary. As opposed to previously proposed models, this model yields a smooth optimization problem where the sparsity is enforced through linear constraints. We show that the Euclidean projection on the polyhedron defined by these constraints can be computed efficiently, and propose a fast gradient method to solve our model. We compare our algorithm with several state-of-the-art methods on synthetic data sets and real-world hyperspectral images.
A fast tomographic method for searching the minimum free energy path
International Nuclear Information System (INIS)
Chen, Changjun; Huang, Yanzhao; Xiao, Yi; Jiang, Xuewei
2014-01-01
Minimum Free Energy Path (MFEP) provides a lot of important information about the chemical reactions, like the free energy barrier, the location of the transition state, and the relative stability between reactant and product. With MFEP, one can study the mechanisms of the reaction in an efficient way. Due to a large number of degrees of freedom, searching the MFEP is a very time-consuming process. Here, we present a fast tomographic method to perform the search. Our approach first calculates the free energy surfaces in a sequence of hyperplanes perpendicular to a transition path. Based on an objective function and the free energy gradient, the transition path is optimized in the collective variable space iteratively. Applications of the present method to model systems show that our method is practical. It can be an alternative approach for finding the state-to-state MFEP
Biochemical method for fast affinity diagnosis in grape-vine transplantation
International Nuclear Information System (INIS)
Lilov, D.
1977-01-01
Long term experiments have proved the affinity of cv. Mavroud in transplantations on various root stocks. Best affinity was observed in the combination cv. Mavroud X Riparia tomanteau, followed, in a descending order, by the combinations Mavroud X Mavroud (autotransplantation), Mavroud X Berlandieri X Riparia Kobber SBB and Mavroud X Riparia 33 EM. In view to establish indices for predicting the transplantation affinity a great number of physiological-biochemical and morphological-anatomical studies were carried out. The results obtained showed that a most clearly expressed positive, statistically significant correlation exists between the amount of 15 N transported from the root stock to the scions, shoots and leaves. As a result, a biochemical method for fast affinity diagnosis in grape-vine transplantation has been developed. The reliability of the method has been checked up also with other cultivars. Up to the present no such method was known in grape-vine science and practice. (author)
International Nuclear Information System (INIS)
Dang Van Mien, H.; Irving, E.; Rousseau, I.
1982-01-01
Motivated by the limitations inherent in the standard approach, a new model reference multivariable adaptive control method is described. This latter control method utilizes as a design tool a simple vector difference equation of the controlled system. The adaptive control method is of the series-parallel direct reference model type and the adjustment algorithm is the standard least squares estimation technics with hyperstability conditions, controlled convergence speed forgetting, regularization and threshold operations. Numerical results are presented which illustrate the interest of the latter approach. The precise problem which has been tackled is the control of the steam generator of the second fast breeder French nuclear reactor called Super-Phenix. After a short description of the plant and its responses at different loads, the principles and the performances of the standard technique control scheme which has been adopted are discussed [fr
Integral equation models for image restoration: high accuracy methods and fast algorithms
International Nuclear Information System (INIS)
Lu, Yao; Shen, Lixin; Xu, Yuesheng
2010-01-01
Discrete models are consistently used as practical models for image restoration. They are piecewise constant approximations of true physical (continuous) models, and hence, inevitably impose bottleneck model errors. We propose to work directly with continuous models for image restoration aiming at suppressing the model errors caused by the discrete models. A systematic study is conducted in this paper for the continuous out-of-focus image models which can be formulated as an integral equation of the first kind. The resulting integral equation is regularized by the Lavrentiev method and the Tikhonov method. We develop fast multiscale algorithms having high accuracy to solve the regularized integral equations of the second kind. Numerical experiments show that the methods based on the continuous model perform much better than those based on discrete models, in terms of PSNR values and visual quality of the reconstructed images
A data-driven prediction method for fast-slow systems
Groth, Andreas; Chekroun, Mickael; Kondrashov, Dmitri; Ghil, Michael
2016-04-01
In this work, we present a prediction method for processes that exhibit a mixture of variability on low and fast scales. The method relies on combining empirical model reduction (EMR) with singular spectrum analysis (SSA). EMR is a data-driven methodology for constructing stochastic low-dimensional models that account for nonlinearity and serial correlation in the estimated noise, while SSA provides a decomposition of the complex dynamics into low-order components that capture spatio-temporal behavior on different time scales. Our study focuses on the data-driven modeling of partial observations from dynamical systems that exhibit power spectra with broad peaks. The main result in this talk is that the combination of SSA pre-filtering with EMR modeling improves, under certain circumstances, the modeling and prediction skill of such a system, as compared to a standard EMR prediction based on raw data. Specifically, it is the separation into "fast" and "slow" temporal scales by the SSA pre-filtering that achieves the improvement. We show, in particular that the resulting EMR-SSA emulators help predict intermittent behavior such as rapid transitions between specific regions of the system's phase space. This capability of the EMR-SSA prediction will be demonstrated on two low-dimensional models: the Rössler system and a Lotka-Volterra model for interspecies competition. In either case, the chaotic dynamics is produced through a Shilnikov-type mechanism and we argue that the latter seems to be an important ingredient for the good prediction skills of EMR-SSA emulators. Shilnikov-type behavior has been shown to arise in various complex geophysical fluid models, such as baroclinic quasi-geostrophic flows in the mid-latitude atmosphere and wind-driven double-gyre ocean circulation models. This pervasiveness of the Shilnikow mechanism of fast-slow transition opens interesting perspectives for the extension of the proposed EMR-SSA approach to more realistic situations.
A FAST METHOD FOR MEASURING THE SIMILARITY BETWEEN 3D MODEL AND 3D POINT CLOUD
Directory of Open Access Journals (Sweden)
Z. Zhang
2016-06-01
Full Text Available This paper proposes a fast method for measuring the partial Similarity between 3D Model and 3D point Cloud (SimMC. It is crucial to measure SimMC for many point cloud-related applications such as 3D object retrieval and inverse procedural modelling. In our proposed method, the surface area of model and the Distance from Model to point Cloud (DistMC are exploited as measurements to calculate SimMC. Here, DistMC is defined as the weighted distance of the distances between points sampled from model and point cloud. Similarly, Distance from point Cloud to Model (DistCM is defined as the average distance of the distances between points in point cloud and model. In order to reduce huge computational burdens brought by calculation of DistCM in some traditional methods, we define SimMC as the ratio of weighted surface area of model to DistMC. Compared to those traditional SimMC measuring methods that are only able to measure global similarity, our method is capable of measuring partial similarity by employing distance-weighted strategy. Moreover, our method is able to be faster than other partial similarity assessment methods. We demonstrate the superiority of our method both on synthetic data and laser scanning data.
Hakamada, Kenichi; Narumi, Shunji; Toyoki, Yoshikazu; Nara, Masaki; Ishido, Kenosuke; Miura, Takuya; Kubo, Norihito; Sasaki, Mutsuo
2008-01-01
AIM: To clarify the usefulness of a new method for performing a pancreaticojejunostomy by using a fast-absorbable suture material irradiated polyglactin 910, and a temporary stent tube for a narrow pancreatic duct with a soft pancreatic texture.
Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus
2016-02-01
We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (tgraphite). We show that in thin graphite crystals the transmitted intensity is a linear function of t. Furthermore, high-resolution (HR) TEM simulations are performed to obtain λ for a 001 zone axis orientation, in a two-beam case and in a low symmetry orientation. Subsequently, HR (used to determine t) and bright-field (to measure I 0(0) and I 0(t)) images were acquired to experimentally determine λ. The experimental value measured in low symmetry orientation matches the calculated value (i.e., λ=225±9 nm). The simulations also show that the linear approximation is valid up to a sample thickness of 3-4 nm regardless of the orientation and up to several ten nanometers for a low symmetry orientation. When compared with standard techniques for thickness determination of graphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.
A fast pulse phase estimation method for X-ray pulsar signals based on epoch folding
Directory of Open Access Journals (Sweden)
Xue Mengfan
2016-06-01
Full Text Available X-ray pulsar-based navigation (XPNAV is an attractive method for autonomous deep-space navigation in the future. The pulse phase estimation is a key task in XPNAV and its accuracy directly determines the navigation accuracy. State-of-the-art pulse phase estimation techniques either suffer from poor estimation accuracy, or involve the maximization of generally non-convex object function, thus resulting in a large computational cost. In this paper, a fast pulse phase estimation method based on epoch folding is presented. The statistical properties of the observed profile obtained through epoch folding are developed. Based on this, we recognize the joint probability distribution of the observed profile as the likelihood function and utilize a fast Fourier transform-based procedure to estimate the pulse phase. Computational complexity of the proposed estimator is analyzed as well. Experimental results show that the proposed estimator significantly outperforms the currently used cross-correlation (CC and nonlinear least squares (NLS estimators, while significantly reduces the computational complexity compared with NLS and maximum likelihood (ML estimators.
DEFF Research Database (Denmark)
Lund, Søren S.; Petersen, Martin; Frandsen, Merete
2011-01-01
LDL cholesterol (LDL-C) is a modifiable cardiovascular disease risk factor. We used 3 LDL-C methods to study the agreement between fasting and postprandial LDL-C in type 2 diabetes (T2DM) patients.......LDL cholesterol (LDL-C) is a modifiable cardiovascular disease risk factor. We used 3 LDL-C methods to study the agreement between fasting and postprandial LDL-C in type 2 diabetes (T2DM) patients....
International Nuclear Information System (INIS)
Dias, M.S.; Koskinas, M.F.; Berretta, J.R.; Fratin, L.; Botelho, S.
1990-01-01
The thermal, epithermal and fast neutron fluxes have been determined experimentally by the activation foil method at position GI, located near the IEA-R1 reactor core. The reactions used were 197 Au (n,gamma) 198 Au, for thermal and epithermal neutrons and 27 Na (n,alpha) 24 Na, for fast neutrons. The activities were measured by the 4π(PC)β-γ coincidence method. (author)
The calculation of site-dependent earthquake motions -3. The method of fast fourier transform
International Nuclear Information System (INIS)
Simpson, I.C.
1976-10-01
The method of Fast Fourier transform (FFT) is applied to the problem of the determination of site-dependent earthquake motions, which takes account of local geological effects. A program, VELAY 1, which uses the FFT method has been written and is described in this report. The assumptions of horizontally stratified, homogeneous, isotropic, linearly viscoelastic layers and a normally incident plane seismic wave are made. Several examples are given, using VELAY 1, of modified surface acceleration-time histories obtained using a selected input acceleration-time history and a representative system of soil layers. There is a discussion concerning the soil properties that need to be measured in order to use VELAY 1 (and similar programs described in previous reports) and hence generate site-dependent ground motions suitable for aseismic design of a nuclear power plant at a given site. (author)
International Nuclear Information System (INIS)
Pickett, T.J.; Shirts, R.B.
1991-01-01
Based on work by Martens and Ezra and partially developed independently by Eaker, we apply an improved method of approximating the quantum energy levels of a system of coupled oscillators using the fast-Fourier transform of classical coordinates and momenta to find quantizing trajectories. Application is made to a two-dimensional system modeling the stretching motions of the HDO molecule. The results are in excellent agreement with quantum calculations. This method is useful because: (1) it gives results which are independent of any separability of the Hamiltonian, (2) it is not limited in the number of degrees of freedom that can be handled, and (3) no zero-order approximation to the system is necessary. Results are equally valid inside and outside of resonance zones
A fast online hit verification method for the single ion hit system at GSI
International Nuclear Information System (INIS)
Du, G.; Fischer, B.; Barberet, P.; Heiss, M.
2006-01-01
For a single ion hit facility built to irradiate specific targets inside biological cells, it is necessary to prove that the ions hit the selected targets reliably because the ion hits usually cannot be seen. That ability is traditionally tested either indirectly by aiming at pre-etched tracks in a nuclear track detector or directly by making the ion tracks inside cells visible using a stain coupled to special proteins produced in response to ion hits. However, both methods are time consuming and hits can be verified only after the experiment. This means that targeting errors in the experiment cannot be corrected during the experiment. Therefore, we have developed a fast online hit verification method that measures the targeting accuracy electronically with a spatial resolution of ±1 μm before cell irradiation takes place. (authors)
A method for detecting the rupture of a fuel element in a fast neutron breeder reactor
International Nuclear Information System (INIS)
Cohen, Paul.
1974-01-01
The method according to the invention is characterized by the steps of balancing a cooling sodium sample driven through a nozzle into a molten salt constituted by a baryum-iodide strontium-iodide mixture, so that a substantial portion of radioactive iodine contingently present in the liquid sodium accumulates in the molten salt through isotopic exchange, separating the molten salt from sodium, balancing (if required) the molten salt with nonradioactive sodium and separating the molten salt from the sodium, and controlling the molten salt in order to determine the presence of iodine, such presence being-indicative of the rupture (or burst) of a fuel element sheath. Such a method is suitable in particular for detecting the rupture of a fuel element in a sodium-cooled fast breeder-reactor [fr
Simplified inelastic analysis methods applied to fast breeder reactor core design
International Nuclear Information System (INIS)
Abo-El-Ata, M.M.
1978-01-01
The paper starts with a review of some currently available simplified inelastic analysis methods used in elevated temperature design for evaluating plastic and thermal creep strains. The primary purpose of the paper is to investigate how these simplified methods may be applied to fast breeder reactor core design where neutron irradiation effects are significant. One of the problems discussed is irradiation-induced creep and its effect on shakedown, ratcheting, and plastic cycling. Another problem is the development of swelling-induced stress which is an additional loading mechanism and must be taken into account. In this respect an expression for swelling-induced stress in the presence of irradiation creep is derived and a model for simplifying the stress analysis under these conditions is proposed. As an example, the effects of irradiation creep and swelling induced stress on the analysis of a thin walled tube under constant internal pressure and intermittent heat fluxes, simulating a fuel pin, is presented
Introducing GAMER: A Fast and Accurate Method for Ray-tracing Galaxies Using Procedural Noise
Groeneboom, N. E.; Dahle, H.
2014-03-01
We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.
Introducing GAMER: A fast and accurate method for ray-tracing galaxies using procedural noise
International Nuclear Information System (INIS)
Groeneboom, N. E.; Dahle, H.
2014-01-01
We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.
Introducing GAMER: A fast and accurate method for ray-tracing galaxies using procedural noise
Energy Technology Data Exchange (ETDEWEB)
Groeneboom, N. E.; Dahle, H., E-mail: nicolaag@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)
2014-03-10
We developed a novel approach for fast and accurate ray-tracing of galaxies using procedural noise fields. Our method allows for efficient and realistic rendering of synthetic galaxy morphologies, where individual components such as the bulge, disk, stars, and dust can be synthesized in different wavelengths. These components follow empirically motivated overall intensity profiles but contain an additional procedural noise component that gives rise to complex natural patterns that mimic interstellar dust and star-forming regions. These patterns produce more realistic-looking galaxy images than using analytical expressions alone. The method is fully parallelized and creates accurate high- and low- resolution images that can be used, for example, in codes simulating strong and weak gravitational lensing. In addition to having a user-friendly graphical user interface, the C++ software package GAMER is easy to implement into an existing code.
A fast computation method for MUSIC spectrum function based on circular arrays
Du, Zhengdong; Wei, Ping
2015-02-01
The large computation amount of multiple signal classification (MUSIC) spectrum function seriously affects the timeliness of direction finding system using MUSIC algorithm, especially in the two-dimensional directions of arrival (DOA) estimation of azimuth and elevation with a large antenna array. This paper proposes a fast computation method for MUSIC spectrum. It is suitable for any circular array. First, the circular array is transformed into a virtual uniform circular array, in the process of calculating MUSIC spectrum, for the cyclic characteristics of steering vector, the inner product in the calculation of spatial spectrum is realised by cyclic convolution. The computational amount of MUSIC spectrum is obviously less than that of the conventional method. It is a very practical way for MUSIC spectrum computation in circular arrays.
Method of a fast selection of inelastic nucleus-nucleus collisions for the CMS experiment
International Nuclear Information System (INIS)
Krasnov, V.A.; Malakhov, A.I.; Savina, M.V.; Shmatov, S.V.; Zarubin, P.I.
1998-01-01
On the basis of the HIJING generator simulation of heavy ion collisions at ultrarelativistic energy scale, a method of a fast selection of inelastic nucleus-nucleus interactions is proposed for the CMS experiment at LHC. The basic idea is to use the time coincidence of signals with resolution better than 1 ns from the two very forward calorimeter arms covering the acceptance 3<|η|<5. The method efficiency is investigated by variation of energy thresholds in the calorimeters for different colliding ion species, namely, PbPb, NbNb, CaCa, OO, pPb, pCa, pp. It is shown that a stable efficiency of event selection (∼98%) is provided in an energy threshold range up to 100 GeV for nuclear collisions at 5 TeV/nucleon in the centre of mass system. In the pp collision case the relevant efficiency drops from 93% down to 80%
Directory of Open Access Journals (Sweden)
Haiwen Li
2018-01-01
Full Text Available The estimation speed of positioning parameters determines the effectiveness of the positioning system. The time of arrival (TOA and direction of arrival (DOA parameters can be estimated by the space-time two-dimensional multiple signal classification (2D-MUSIC algorithm for array antenna. However, this algorithm needs much time to complete the two-dimensional pseudo spectral peak search, which makes it difficult to apply in practice. Aiming at solving this problem, a fast estimation method of space-time two-dimensional positioning parameters based on Hadamard product is proposed in orthogonal frequency division multiplexing (OFDM system, and the Cramer-Rao bound (CRB is also presented. Firstly, according to the channel frequency domain response vector of each array, the channel frequency domain estimation vector is constructed using the Hadamard product form containing location information. Then, the autocorrelation matrix of the channel response vector for the extended array element in frequency domain and the noise subspace are calculated successively. Finally, by combining the closed-form solution and parameter pairing, the fast joint estimation for time delay and arrival direction is accomplished. The theoretical analysis and simulation results show that the proposed algorithm can significantly reduce the computational complexity and guarantee that the estimation accuracy is not only better than estimating signal parameters via rotational invariance techniques (ESPRIT algorithm and 2D matrix pencil (MP algorithm but also close to 2D-MUSIC algorithm. Moreover, the proposed algorithm also has certain adaptability to multipath environment and effectively improves the ability of fast acquisition of location parameters.
A two-step method for fast and reliable EUV mask metrology
Helfenstein, Patrick; Mochi, Iacopo; Rajendran, Rajeev; Yoshitake, Shusuke; Ekinci, Yasin
2017-03-01
One of the major obstacles towards the implementation of extreme ultraviolet lithography for upcoming technology nodes in semiconductor industry remains the realization of a fast and reliable detection methods patterned mask defects. We are developing a reflective EUV mask-scanning lensless imaging tool (RESCAN), installed at the Swiss Light Source synchrotron at the Paul Scherrer Institut. Our system is based on a two-step defect inspection method. In the first step, a low-resolution defect map is generated by die to die comparison of the diffraction patterns from areas with programmed defects, to those from areas that are known to be defect-free on our test sample. In a later stage, a die to database comparison will be implemented in which the measured diffraction patterns will be compared to those calculated directly from the mask layout. This Scattering Scanning Contrast Microscopy technique operates purely in the Fourier domain without the need to obtain the aerial image and, given a sufficient signal to noise ratio, defects are found in a fast and reliable way, albeit with a location accuracy limited by the spot size of the incident illumination. Having thus identified rough locations for the defects, a fine scan is carried out in the vicinity of these locations. Since our source delivers coherent illumination, we can use an iterative phase-retrieval method to reconstruct the aerial image of the scanned area with - in principle - diffraction-limited resolution without the need of an objective lens. Here, we will focus on the aerial image reconstruction technique and give a few examples to illustrate the capability of the method.
A fast button surface defects detection method based on convolutional neural network
Liu, Lizhe; Cao, Danhua; Wu, Songlin; Wu, Yubin; Wei, Taoran
2018-01-01
Considering the complexity of the button surface texture and the variety of buttons and defects, we propose a fast visual method for button surface defect detection, based on convolutional neural network (CNN). CNN has the ability to extract the essential features by training, avoiding designing complex feature operators adapted to different kinds of buttons, textures and defects. Firstly, we obtain the normalized button region and then use HOG-SVM method to identify the front and back side of the button. Finally, a convolutional neural network is developed to recognize the defects. Aiming at detecting the subtle defects, we propose a network structure with multiple feature channels input. To deal with the defects of different scales, we take a strategy of multi-scale image block detection. The experimental results show that our method is valid for a variety of buttons and able to recognize all kinds of defects that have occurred, including dent, crack, stain, hole, wrong paint and uneven. The detection rate exceeds 96%, which is much better than traditional methods based on SVM and methods based on template match. Our method can reach the speed of 5 fps on DSP based smart camera with 600 MHz frequency.
Advanced methods comparisons of reaction rates in the Purdue Fast Breeder Blanket Facility
International Nuclear Information System (INIS)
Hill, R.N.; Ott, K.O.
1988-01-01
A review of worldwide results revealed that reaction rates in the blanket region are generally underpredicted with the discrepancy increasing with penetration; however, these results vary widely. Experiments in the large uniform Purdue Fast Breeder Blanket Facility (FBBF) blanket yield an accurate quantification of this discrepancy. Using standard production code methods (diffusion theory with 50 group cross sections), a consistent Calculated/Experimental (C/E) drop-off was observed for various reaction rates. A 50% increase in the calculated results at the outer edge of the blanket is necessary for agreement with experiments. The usefulness of refined group constant generation utilizing specialized weighting spectra and transport theory methods in correcting this discrepancy was analyzed. Refined group constants reduce the discrepancy to half that observed using the standard method. The surprising result was that transport methods had no effect on the blanket deviations; thus, transport theory considerations do not constitute or even contribute to an explanation of the blanket discrepancies. The residual blanket C/E drop-off (about half the standard drop-off) using advanced methods must be caused by some approximations which are applied in all current methods. 27 refs., 3 figs., 1 tab
Creep/fatigue damage prediction of fast reactor components using shakedown methods
International Nuclear Information System (INIS)
Buckthorpe, D.E.
1997-01-01
The present status of the shakedown method is reviewed, the application of the shakedown based principles to complex hardening and creep behaviour is described and justified and the prediction of damage against design criteria outlined. Comparisons are made with full inelastic analysis solutions where these are available and against damage assessments using elastic and inelastic design code methods. Current and future developments of the method are described including a summary of the advances made in the development of the post process ADAPT, which has enabled the method to be applied to complex geometry features and loading cases. The paper includes a review of applications of the method to typical Fast Reactor structural example cases within the primary and secondary circuits. For the primary circuit this includes structures such as the large diameter internal shells which are surrounded by hot sodium and subject to slow and rapid thermal transient loadings. One specific case is the damage assessment associated with thermal stratifications within sodium and the effects of moving sodium surfaces arising from reactor trip conditions. Other structures covered are geometric features within components such as the Above Core structure and Intermediate Heat Exchanger. For the secondary circuit the method has been applied to alternative and more complex forms of geometry namely thick section tubeplates of the Steam Generator and a typical secondary circuit piping run. Both of these applications are in an early stage of development but are expected to show significant advantages with respect to creep and fatigue damage estimation compared with existing code methods. The principle application of the method to design has so far been focused on Austenitic Stainless steel components however current work shows some significant benefits may be possible from the application of the method to structures made from Ferritic steels such as Modified 9Cr 1Mo. This aspect is briefly
Fast time- and frequency-domain finite-element methods for electromagnetic analysis
Lee, Woochan
Fast electromagnetic analysis in time and frequency domain is of critical importance to the design of integrated circuits (IC) and other advanced engineering products and systems. Many IC structures constitute a very large scale problem in modeling and simulation, the size of which also continuously grows with the advancement of the processing technology. This results in numerical problems beyond the reach of existing most powerful computational resources. Different from many other engineering problems, the structure of most ICs is special in the sense that its geometry is of Manhattan type and its dielectrics are layered. Hence, it is important to develop structure-aware algorithms that take advantage of the structure specialties to speed up the computation. In addition, among existing time-domain methods, explicit methods can avoid solving a matrix equation. However, their time step is traditionally restricted by the space step for ensuring the stability of a time-domain simulation. Therefore, making explicit time-domain methods unconditionally stable is important to accelerate the computation. In addition to time-domain methods, frequency-domain methods have suffered from an indefinite system that makes an iterative solution difficult to converge fast. The first contribution of this work is a fast time-domain finite-element algorithm for the analysis and design of very large-scale on-chip circuits. The structure specialty of on-chip circuits such as Manhattan geometry and layered permittivity is preserved in the proposed algorithm. As a result, the large-scale matrix solution encountered in the 3-D circuit analysis is turned into a simple scaling of the solution of a small 1-D matrix, which can be obtained in linear (optimal) complexity with negligible cost. Furthermore, the time step size is not sacrificed, and the total number of time steps to be simulated is also significantly reduced, thus achieving a total cost reduction in CPU time. The second contribution
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Copper
American Society for Testing and Materials. Philadelphia
2011-01-01
1.1 This test method covers procedures for measuring reaction rates by the activation reaction 63Cu(n,α)60Co. The cross section for 60Co produced in this reaction increases rapidly with neutrons having energies greater than about 5 MeV. 60Co decays with a half-life of 1925.27 days (±0.29 days)(1) and emits two gamma rays having energies of 1.1732278 and 1.332492 MeV (1). The isotopic content of natural copper is 69.17 % 63Cu and 30.83 % 65Cu (2). The neutron reaction, 63Cu(n,γ)64Cu, produces a radioactive product that emits gamma rays which might interfere with the counting of the 60Co gamma rays. 1.2 With suitable techniques, fission-neutron fluence rates above 109 cm−2·s−1 can be determined. The 63Cu(n,α)60Co reaction can be used to determine fast-neutron fluences for irradiation times up to about 15 years (for longer irradiations, see Practice E261). 1.3 Detailed procedures for other fast-neutron detectors are referenced in Practice E261. 1.4 This standard does not purport to address all of the...
A fast method to emulate an iterative POCS image reconstruction algorithm.
Zeng, Gengsheng L
2017-10-01
Iterative image reconstruction algorithms are commonly used to optimize an objective function, especially when the objective function is nonquadratic. Generally speaking, the iterative algorithms are computationally inefficient. This paper presents a fast algorithm that has one backprojection and no forward projection. This paper derives a new method to solve an optimization problem. The nonquadratic constraint, for example, an edge-preserving denoising constraint is implemented as a nonlinear filter. The algorithm is derived based on the POCS (projections onto projections onto convex sets) approach. A windowed FBP (filtered backprojection) algorithm enforces the data fidelity. An iterative procedure, divided into segments, enforces edge-enhancement denoising. Each segment performs nonlinear filtering. The derived iterative algorithm is computationally efficient. It contains only one backprojection and no forward projection. Low-dose CT data are used for algorithm feasibility studies. The nonlinearity is implemented as an edge-enhancing noise-smoothing filter. The patient studies results demonstrate its effectiveness in processing low-dose x ray CT data. This fast algorithm can be used to replace many iterative algorithms. © 2017 American Association of Physicists in Medicine.
Method to Reduce Long-lived Fission Products by Nuclear Transmutations with Fast Spectrum Reactors.
Chiba, Satoshi; Wakabayashi, Toshio; Tachi, Yoshiaki; Takaki, Naoyuki; Terashima, Atsunori; Okumura, Shin; Yoshida, Tadashi
2017-10-24
Transmutation of long-lived fission products (LLFPs: 79 Se, 93 Zr, 99 Tc, 107 Pd, 129 I, and 135 Cs) into short-lived or non-radioactive nuclides by fast neutron spectrum reactors without isotope separation has been proposed as a solution to the problem of radioactive wastes disposal. Despite investigation of many methods, such transmutation remains technologically difficult. To establish an effective and efficient transmutation system, we propose a novel neutron moderator material, yttrium deuteride (YD 2 ), to soften the neutron spectrum leaking from the reactor core. Neutron energy spectra and effective half-lives of LLFPs, transmutation rates, and support ratios were evaluated with the continuous-energy Monte Carlo code MVP-II/MVP-BURN and the JENDL-4.0 cross section library. With the YD 2 moderator in the radial blanket and shield regions, effective half-lives drastically decreased from 106 to 102 years and the support ratios reached 1.0 for all six LLFPs. This successful development and implementation of a transmutation system for LLFPs without isotope separation contributes to a the ability of fast spectrum reactors to reduce radioactive waste by consuming their own LLFPs.
IN SEARCH OF A FAST SCREENING METHOD FOR DETECTING THE MALINGERING OF COGNITIVE IMPAIRMENT
Directory of Open Access Journals (Sweden)
Amada Ampudia
2012-07-01
Full Text Available Forensic settings demand expedient and conclusive forensic psychological assessment. The aim of this study was to design a simple and fast, but reliable psychometric instrument for detecting the malingering of cognitive impairment. In a quasi-experimental design, 156 individuals were divided into three groups: a normal group with no cognitive impairment; a Mild Cognitive Impairment (MCI group; and a group of informed malingerers with no MCI who feigned cognitive impairment. Receiver Operating Curve (ROC analysis of the Test of Memory Malingering (TOMM, and of several subtests of the Wechsler Memory Scale (WMS-III revealed that the WMS-III was as reliable and accurate as the TOMM in discriminating malingerers from the honest. The results revealed that the diagnostic accuracy, sensitivity and specificity of the WMS-III Auditory Recognition Delayed of Verbal Paired Associates subtest was similar to the TOMM in discriminating malingering from genuine memory impairment. In conclusion, the WMS-III Recognition of Verbal Paired Associates subtest and the TOMM provide a fast, valid and reliable screening method for detecting the malingering of cognitive impairment.
A Fast Optimization Method for Reliability and Performance of Cloud Services Composition Application
Directory of Open Access Journals (Sweden)
Zhao Wu
2013-01-01
Full Text Available At present the cloud computing is one of the newest trends of distributed computation, which is propelling another important revolution of software industry. The cloud services composition is one of the key techniques in software development. The optimization for reliability and performance of cloud services composition application, which is a typical stochastic optimization problem, is confronted with severe challenges due to its randomness and long transaction, as well as the characteristics of the cloud computing resources such as openness and dynamic. The traditional reliability and performance optimization techniques, for example, Markov model and state space analysis and so forth, have some defects such as being too time consuming and easy to cause state space explosion and unsatisfied the assumptions of component execution independence. To overcome these defects, we propose a fast optimization method for reliability and performance of cloud services composition application based on universal generating function and genetic algorithm in this paper. At first, a reliability and performance model for cloud service composition application based on the multiple state system theory is presented. Then the reliability and performance definition based on universal generating function is proposed. Based on this, a fast reliability and performance optimization algorithm is presented. In the end, the illustrative examples are given.
Feasibility of a Monte Carlo-deterministic hybrid method for fast reactor analysis
Energy Technology Data Exchange (ETDEWEB)
Heo, W.; Kim, W.; Kim, Y. [Korea Advanced Institute of Science and Technology - KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Yun, S. [Korea Atomic Energy Research Institute - KAERI, 989-111 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)
2013-07-01
A Monte Carlo and deterministic hybrid method is investigated for the analysis of fast reactors in this paper. Effective multi-group cross sections data are generated using a collision estimator in the MCNP5. A high order Legendre scattering cross section data generation module was added into the MCNP5 code. Both cross section data generated from MCNP5 and TRANSX/TWODANT using the homogeneous core model were compared, and were applied to DIF3D code for fast reactor core analysis of a 300 MWe SFR TRU burner core. For this analysis, 9 groups macroscopic-wise data was used. In this paper, a hybrid calculation MCNP5/DIF3D was used to analyze the core model. The cross section data was generated using MCNP5. The k{sub eff} and core power distribution were calculated using the 54 triangle FDM code DIF3D. A whole core calculation of the heterogeneous core model using the MCNP5 was selected as a reference. In terms of the k{sub eff}, 9-group MCNP5/DIF3D has a discrepancy of -154 pcm from the reference solution, 9-group TRANSX/TWODANT/DIF3D analysis gives -1070 pcm discrepancy. (authors)
An assessment of methods of calculating sodium-voiding reactivity in plutonium-fuelled fast reactors
International Nuclear Information System (INIS)
Butland, A.T.D.; Simmons, W.N.; Stevenson, J.M.
1980-01-01
After a survey of the requirements an assessment of the accuracy of calculations of the sodium-void effect using UK methods and data is made on the basis of the following work: (a) The analysis of small and large sodium voids in the MOZART and Zebra 13 small (300 MW(e)) fast reactor mock-ups and the BIZET large fast reactor mock-ups, all of conventional design. The analysis was carried out using the UK FGL5 fine group nuclear data library, the MURAL cell code, whole reactor diffusion theory calculations of the neutron flux and perturbation theory methods. Exact perturbation theory was used in many cases, otherwise first-order perturbation theory calculations were adjusted to give results equivalent to exact perturbation theory. (b) Theoretical studies of some effects, including the following: (i) The effects of extrapolating to fuel operating temperature; (ii) Fuel-cycle and burnup effects, including the gradual replacement through a fuel cycle of control-rod absorption by fission product absorption, the loss of fissile material and the change in fuel nuclide relative composition; (iii) The heterogeneity effects of large fuelled subassemblies in pin geometry. (c) Theoretical studies of approximations in the calculational methods, including the following: (i) The importance in the whole reactor calculation of the energy group structure and the spatial mesh, including comparisons of calculations in two (RZ) and three-dimensional geometry; (ii) The importance of reactor material boundaries in the calculation of resonance shielding effects; (iii) The use of neutron fluxes calculated using neutron diffusion theory rather than transport theory. (author)
Fast and simple method for semiquantitative determination of calcium propionate in bread samples
Directory of Open Access Journals (Sweden)
Chutima Matayatsuk Phechkrajang
2017-04-01
Full Text Available Calcium propionate has been widely used as a preservative in bakery and in bread. It is sometimes not carefully used, or a high concentration is added to preserve products. High consumption of calcium propionate can lead to several health problems. This study aims to develop a fast and simple semiquantitative method based on color complex formation for the determination of calcium propionate in a bread sample. A red–brown complex was obtained from the reaction of ferric ammonium sulfate and propionate anion. The product was rapidly formed and easily observed with the concentration of propionate anion >0.4 mg/mL. A high-performance liquid chromatography (HPLC method was also developed and validated for comparison. Twenty-two bread samples from three markets near Bangkok were randomly selected and assayed for calcium propionate using the above two developed methods. The results showed that 19/22 samples contained calcium propionate >2000 mg/kg. The results of the complex formation method agreed with the HPLC method.
Fast and simple method for semiquantitative determination of calcium propionate in bread samples.
Phechkrajang, Chutima Matayatsuk; Yooyong, Surin
2017-04-01
Calcium propionate has been widely used as a preservative in bakery and in bread. It is sometimes not carefully used, or a high concentration is added to preserve products. High consumption of calcium propionate can lead to several health problems. This study aims to develop a fast and simple semiquantitative method based on color complex formation for the determination of calcium propionate in a bread sample. A red-brown complex was obtained from the reaction of ferric ammonium sulfate and propionate anion. The product was rapidly formed and easily observed with the concentration of propionate anion >0.4 mg/mL. A high-performance liquid chromatography (HPLC) method was also developed and validated for comparison. Twenty-two bread samples from three markets near Bangkok were randomly selected and assayed for calcium propionate using the above two developed methods. The results showed that 19/22 samples contained calcium propionate >2000 mg/kg. The results of the complex formation method agreed with the HPLC method. Copyright © 2016. Published by Elsevier B.V.
International Nuclear Information System (INIS)
Reis Filho, P.E.G. dos
1982-01-01
A new synthesis method to substitute for the classical method of finite diferences for XYZ geometry (geometry of critical experiments in fast reactors), is developed. The new method allows a fine energy group division, that is, finer than the 6 groups division used in calculations of power core specification. (E.G.) [pt
Germination test as a fast method to detect glyphosate-resistant sourgrass
Directory of Open Access Journals (Sweden)
Marcos Altomani Neves Dias
2015-01-01
Full Text Available The occurrence of weed species with different levels of resistance to glyphosate has increasingly spread in agricultural areas. In Brazil, sourgrass is among the main species presenting issues in this regard. Thus, fast and reliable methods to detect glyphosate resistance are of special interest for this specie, either for research or rational management purposes. This study was carried out to verify the feasibility of using the germination test to detect glyphosate resistance in sourgrass. The experiment was conducted with two sourgrass biotypes, with different levels of susceptibility to glyphosate. The seeds were previously imbibed in solutions composed of 0, 0.1875%, 0.25%, 0.75%, 1.5%, 3% and 6% of glyphosate during two periods, five and ten minutes, and submitted to germination tests. The results indicate the germination test as a feasible and time-saving approach to evaluate glyphosate-resistant sourgrass, with results available in seven days.
Germination test as a fast method to detect glyphosate-resistant sourgrass
Directory of Open Access Journals (Sweden)
Marcos Altomani Neves Dias
2015-09-01
Full Text Available The occurrence of weed species with different levels of resistance to glyphosate has increasingly spread in agricultural areas. In Brazil, sourgrass is among the main species presenting issues in this regard. Thus, fast and reliable methods to detect glyphosate resistance are of special interest for this specie, either for research or rational management purposes. This study was carried out to verify the feasibility of using the germination test to detect glyphosate resistance in sourgrass. The experiment was conducted with two sourgrass biotypes, with different levels of susceptibility to glyphosate. The seeds were previously imbibed in solutions composed of 0, 0.1875%, 0.25%, 0.75%, 1.5%, 3% and 6% of glyphosate during two periods, five and ten minutes, and submitted to germination tests. The results indicate the germination test as a feasible and time-saving approach to evaluate glyphosate-resistant sourgrass, with results available in seven days.
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Aluminum
American Society for Testing and Materials. Philadelphia
2011-01-01
1.1 This test method covers procedures measuring reaction rates by the activation reaction 27Al(n,α)24Na. 1.2 This activation reaction is useful for measuring neutrons with energies above approximately 6.5 MeV and for irradiation times up to about 2 days (for longer irradiations, see Practice E261). 1.3 With suitable techniques, fission-neutron fluence rates above 106 cm−2·s−1 can be determined. 1.4 Detailed procedures for other fast neutron detectors are referenced in Practice E261. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Reduced dynamics in spin-boson models: A method for both slow and fast bath
International Nuclear Information System (INIS)
Golosov, Andrei A.; Friesner, Richard A.; Pechukas, Philip
2000-01-01
We study a model for treating dissipative systems, a one dimensional quantum system coupled to a harmonic bath. The dynamics of such a system can be described by Feynman's path integral expression for the reduced density matrix. In this formulation the interaction of the system with the environment is stored in the influence functional. Recently we showed that fast environmental modes that give rise to correlations in the influence functional which are short range in time can be treated efficiently by a memory equation algorithm, which is a discretized version of a master equation. In this work we extend this approach to treat slow environmental modes as well, thereby efficiently linking adiabatic and nonadiabatic regimes. In this extended method the long range correlations in the influence functional arising from slow bath modes are taken into account through Stock's semiclassical self-consistent-field approach. (c) 2000 American Institute of Physics
Guan, W.; Cheng, X.; Huang, J.; Huber, G.; Li, W.; McCammon, J. A.; Zhang, B.
2018-06-01
RPYFMM is a software package for the efficient evaluation of the potential field governed by the Rotne-Prager-Yamakawa (RPY) tensor interactions in biomolecular hydrodynamics simulations. In our algorithm, the RPY tensor is decomposed as a linear combination of four Laplace interactions, each of which is evaluated using the adaptive fast multipole method (FMM) (Greengard and Rokhlin, 1997) where the exponential expansions are applied to diagonalize the multipole-to-local translation operators. RPYFMM offers a unified execution on both shared and distributed memory computers by leveraging the DASHMM library (DeBuhr et al., 2016, 2018). Preliminary numerical results show that the interactions for a molecular system of 15 million particles (beads) can be computed within one second on a Cray XC30 cluster using 12,288 cores, while achieving approximately 54% strong-scaling efficiency.
Dynamic analysis of fast-acting solenoid valves using finite element method
International Nuclear Information System (INIS)
Kwon, Ki Tae; Han, Hwa Taik
2001-01-01
It is intended to develop an algorithm for dynamic simulation of fast-acting solenoid valves. The coupled equations of the electric, magnetic, and mechanical systems should be solved simultaneously in a transient nonlinear manner. The transient nonlinear electromagnetic field is analyzed by the Finite Element Method (FEM), which is coupled with nonlinear electronic circuitry. The dynamic movement of the solenoid valve is analyzed at every time step from the force balances acting on the plunger, which include the electromagnetic force calculated from the finite element analysis as well as the elastic force by a spring and the hydrodynamic pressure force along the flow passage. Dynamic responses of the solenoid valves predicted by this algorithm agree well the experimental results including bouncing effects
International Nuclear Information System (INIS)
Zhang Wen; Haas, Stephan
2009-01-01
An implementation of the fast multiple method (FMM) is performed for magnetic systems with long-ranged dipolar interactions. Expansion in spherical harmonics of the original FMM is replaced by expansion of polynomials in Cartesian coordinates, which is considerably simpler. Under open boundary conditions, an expression for multipole moments of point dipoles in a cell is derived. These make the program appropriate for nanomagnetic simulations, including magnetic nanoparticles and ferrofluids. The performance is optimized in terms of cell size and parameter set (expansion order and opening angle) and the trade off between computing time and accuracy is quantitatively studied. A rule of thumb is proposed to decide the appropriate average number of dipoles in the smallest cells, and an optimal choice of parameter set is suggested. Finally, the superiority of Cartesian coordinate FMM is demonstrated by comparison to spherical harmonics FMM and FFT.
Fast data reconstructed method of Fourier transform imaging spectrometer based on multi-core CPU
Yu, Chunchao; Du, Debiao; Xia, Zongze; Song, Li; Zheng, Weijian; Yan, Min; Lei, Zhenggang
2017-10-01
Imaging spectrometer can gain two-dimensional space image and one-dimensional spectrum at the same time, which shows high utility in color and spectral measurements, the true color image synthesis, military reconnaissance and so on. In order to realize the fast reconstructed processing of the Fourier transform imaging spectrometer data, the paper designed the optimization reconstructed algorithm with OpenMP parallel calculating technology, which was further used for the optimization process for the HyperSpectral Imager of `HJ-1' Chinese satellite. The results show that the method based on multi-core parallel computing technology can control the multi-core CPU hardware resources competently and significantly enhance the calculation of the spectrum reconstruction processing efficiency. If the technology is applied to more cores workstation in parallel computing, it will be possible to complete Fourier transform imaging spectrometer real-time data processing with a single computer.
A simple and fast method to determine the parameters for fuzzy c-means cluster analysis
DEFF Research Database (Denmark)
Schwämmle, Veit; Jensen, Ole Nørregaard
2010-01-01
MOTIVATION: Fuzzy c-means clustering is widely used to identify cluster structures in high-dimensional datasets, such as those obtained in DNA microarray and quantitative proteomics experiments. One of its main limitations is the lack of a computationally fast method to set optimal values...... of algorithm parameters. Wrong parameter values may either lead to the inclusion of purely random fluctuations in the results or ignore potentially important data. The optimal solution has parameter values for which the clustering does not yield any results for a purely random dataset but which detects cluster...... formation with maximum resolution on the edge of randomness. RESULTS: Estimation of the optimal parameter values is achieved by evaluation of the results of the clustering procedure applied to randomized datasets. In this case, the optimal value of the fuzzifier follows common rules that depend only...
MOSS-5: A Fast Method of Approximating Counts of 5-Node Graphlets in Large Graphs
Wang, Pinghui
2017-09-26
Counting 3-, 4-, and 5-node graphlets in graphs is important for graph mining applications such as discovering abnormal/evolution patterns in social and biology networks. In addition, it is recently widely used for computing similarities between graphs and graph classification applications such as protein function prediction and malware detection. However, it is challenging to compute these metrics for a large graph or a large set of graphs due to the combinatorial nature of the problem. Despite recent efforts in counting triangles (a 3-node graphlet) and 4-node graphlets, little attention has been paid to characterizing 5-node graphlets. In this paper, we develop a computationally efficient sampling method to estimate 5-node graphlet counts. We not only provide fast sampling methods and unbiased estimators of graphlet counts, but also derive simple yet exact formulas for the variances of the estimators which is of great value in practice-the variances can be used to bound the estimates\\' errors and determine the smallest necessary sampling budget for a desired accuracy. We conduct experiments on a variety of real-world datasets, and the results show that our method is several orders of magnitude faster than the state-of-the-art methods with the same accuracy.
Flow Modeling in Pelton Turbines by an Accurate Eulerian and a Fast Lagrangian Evaluation Method
Directory of Open Access Journals (Sweden)
A. Panagiotopoulos
2015-01-01
Full Text Available The recent development of CFD has allowed the flow modeling in impulse hydro turbines that includes complex phenomena like free surface flow, multifluid interaction, and unsteady, time dependent flow. Some commercial and open-source CFD codes, which implement Eulerian methods, have been validated against experimental results showing satisfactory accuracy. Nevertheless, further improvement of accuracy is still a challenge, while the computational cost is very high and unaffordable for multiparametric design optimization of the turbine’s runner. In the present work a CFD Eulerian approach is applied at first, in order to simulate the flow in the runner of a Pelton turbine model installed at the laboratory. Then, a particulate method, the Fast Lagrangian Simulation (FLS, is used for the same case, which is much faster and hence potentially suitable for numerical design optimization, providing that it can achieve adequate accuracy. The results of both methods for various turbine operation conditions, as also for modified runner and bucket designs, are presented and discussed in the paper. In all examined cases the FLS method shows very good accuracy in predicting the hydraulic efficiency of the runner, although the computed flow evolution and the torque curve exhibit some systematic differences from the Eulerian results.
Directory of Open Access Journals (Sweden)
Abdin T
2015-06-01
Full Text Available Tamer Abdin,1 Gideon Zamir,2 Alon Pikarsky,2 Ran Katz,1 Ezekiel H Landau,1 Ofer N Gofrit1 1Department of Urology, 2Department of General Surgery, Hadassah Hebrew University Hospital, Jerusalem, Israel Aim: To report on a simple and rapid method of urinary diversion. This method was applied successfully in different clinical scenarios when primary reconstruction of the ureters was not possible. Materials and methods: The disconnected ureter is catheterized by a feeding tube. The tube is secured with sutures and brought out to the lateral abdominal wall as cutaneous tube ureterostomy (CTU. Results: This method was applied in three different clinical scenarios: a 40-year-old man who sustained multiple high-velocity gunshots to the pelvis with combined rectal and bladder trigone injuries and massive bleeding from a comminuted pubic fracture. Damage control included colostomy and bilateral CTUs. A 26-year-old woman had transection of the right lower ureter during abdominal hysterectomy. Diagnosis was delayed for 3 weeks when the patient developed sepsis. The right kidney was diverted with a CTU. A 37-year-old male suffered from bladder perforation and hemorrhagic shock. Emergency cystectomy was done and urinary diversion was accomplished with bilateral CTUs. In all cases, effective drainage of the urinary system was achieved with normalization of kidney function. Conclusion: When local or systemic conditions preclude definitive repair and damage control surgery is needed, CTU provides fast and effective urinary diversion. Keywords: Ureter, trauma, tube cutenuous ureterostomy
Nimalaratne, Chamila; Lopes-Lutz, Daise; Schieber, Andreas; Wu, Jianping
2015-12-01
A fast isocratic liquid chromatography method was developed for the simultaneous quantification of eight xanthophylls (13-Z-lutein, 13'-Z-lutein, 13-Z-zeaxanthin, all-E-lutein, all-E-zeaxanthin, all-E-canthaxanthin, all-E-β-apo-8'-carotenoic acid ethyl ester and all-E-β-apo-8'-carotenal) within 12 min, compared to 90 min by the conventional high-performance liquid chromatography method. The separation was achieved on a YMC C30 reversed-phase column (100 mm x 2.0 mm; 3 μm) operated at 20°C using a methanol/tert-butyl methyl ether/water solvent system at a flow rate of 0.8 mL/min. The method was successfully applied to quantify lutein and zeaxanthin stereoisomers in egg yolk, raw and cooked spinach, and a dietary supplement. The method can be used for the rapid analysis of xanthophyll isomers in different food products and for quality control purposes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
International Nuclear Information System (INIS)
Preoteasa, E.A.; Constantinescu, B.; Preoteasa, Elena
2000-01-01
Composite materials replaced silver amalgam in many applications for restorative dentistry. Among biomaterials their production develops at a high rate, due especially to the progress of materials forming their mineral filling. However they bring at the interface with enamel and dentine elements foreign to the organism, of whom not all are specified by manufacturers; also, some of these elements' biological action has not been studied. Due to its ability to analyze the elemental composition at the biomaterial's surface, as well as the concentration changes that may occur in the mouth or in model systems, X-ray fluorescence (XRF) is a method suited to approach such problems. Here we examined the potential of XRF for fast analysis of some dental composite materials. Flat disk-shaped samples have been prepared by polymerization and the measurements have been performed with a spectrometric chain containing a 241 Am source, a Si(Li) detector and a multichannel analyzer. The radioisotope-excited XRF detected the following Z > 20 elements in the studied composite materials: Ba in Charisma (Kulzer) and Pekafill (Bayer); Zr, Ba, Yb [and traces of In] in Tetric Ceram (Vivadent); Zr, Hf in Valux Plus and Sr, Ba and traces of Cu in F2000 compomer (both from 3M Dental). Among older materials, Evicrol (Spofa) and Alphaplast (DGM) showed Ca and Fe, while Concise (3M Dental) contained only undetectable (Z < 20) elements. XRF proved valuable especially for analysis of major and minor inorganic elements in the dental composite materials. The method could be used also in fast expertise of these biomaterials (e.g. in customs and commercial applications). (authors)
A fast non-Fourier method for Landau-fluid operators
Energy Technology Data Exchange (ETDEWEB)
Dimits, A. M., E-mail: dimits1@llnl.gov; Joseph, I.; Umansky, M. V. [Lawrence Livermore National Laboratory, L-637, P.O. Box 808, Livermore, California 94511-0808 (United States)
2014-05-15
An efficient and versatile non-Fourier method for the computation of Landau-fluid (LF) closure operators [Hammett and Perkins, Phys. Rev. Lett. 64, 3019 (1990)] is presented, based on an approximation by a sum of modified-Helmholtz-equation solves (SMHS) in configuration space. This method can yield fast-Fourier-like scaling of the computational time requirements and also provides a very compact data representation of these operators, even for plasmas with large spatial nonuniformity. As a result, the method can give significant savings compared with direct application of “delocalization kernels” [e.g., Schurtz et al., Phys. Plasmas 7, 4238 (2000)], both in terms of computational cost and memory requirements. The method is of interest for the implementation of Landau-fluid models in situations where the spatial nonuniformity, particular geometry, or boundary conditions render a Fourier implementation difficult or impossible. Systematic procedures have been developed to optimize the resulting operators for accuracy and computational cost. The four-moment Landau-fluid model of Hammett and Perkins has been implemented in the BOUT++ code using the SMHS method for LF closure. Excellent agreement has been obtained for the one-dimensional plasma density response function between driven initial-value calculations using this BOUT++ implementation and matrix eigenvalue calculations using both Fourier and SMHS non-Fourier implementations of the LF closures. The SMHS method also forms the basis for the implementation, which has been carried out in the BOUT++ code, of the parallel and toroidal drift-resonance LF closures. The method is a key enabling tool for the extension of gyro-Landau-fluid models [e.g., Beer and Hammett, Phys. Plasmas 3, 4046 (1996)] to codes that treat regions with strong profile variation, such as the tokamak edge and scrapeoff-layer.
A fast combination method in DSmT and its application to recommender system.
Dong, Yilin; Li, Xinde; Liu, Yihai
2018-01-01
In many applications involving epistemic uncertainties usually modeled by belief functions, it is often necessary to approximate general (non-Bayesian) basic belief assignments (BBAs) to subjective probabilities (called Bayesian BBAs). This necessity occurs if one needs to embed the fusion result in a system based on the probabilistic framework and Bayesian inference (e.g. tracking systems), or if one needs to make a decision in the decision making problems. In this paper, we present a new fast combination method, called modified rigid coarsening (MRC), to obtain the final Bayesian BBAs based on hierarchical decomposition (coarsening) of the frame of discernment. Regarding this method, focal elements with probabilities are coarsened efficiently to reduce computational complexity in the process of combination by using disagreement vector and a simple dichotomous approach. In order to prove the practicality of our approach, this new approach is applied to combine users' soft preferences in recommender systems (RSs). Additionally, in order to make a comprehensive performance comparison, the proportional conflict redistribution rule #6 (PCR6) is regarded as a baseline in a range of experiments. According to the results of experiments, MRC is more effective in accuracy of recommendations compared to original Rigid Coarsening (RC) method and comparable in computational time.
Energy Technology Data Exchange (ETDEWEB)
Nishizawa, Shigeru; Yokoyama, Tetsuo; Uemura, Kenichi [Hamamatsu Univ. School of Medicine, Shizuoka (Japan)
1999-04-01
Neuroimaging of vestibular schwannoma was performed with the fat-suppression spoiled gradient recalled acquisition in the steady state (SPGR) method and magnetic resonance (MR) cisternography, which is a fast spin echo method using a long echo train length, for the preoperative evaluation of the lateral extension of the tumor in the internal auditory canal, and the anatomical identification of the posterior semicircular canal and the nerves in the canal distal to the tumor. The SPGR method overestimated the lateral extension in eight cases, probably because of enhancement of the nerves adjacent to the tumor in the canal. The posterior semicircular canal could not be clearly identified, and the cranial nerves in the canal were shown only as a nerve bundle. In contrast, MR cisternography showed clear images of the lateral extension of the tumor and the facial and cochlear nerves adjacent to the tumor in the internal auditory canal. The anatomical location of the posterior semicircular canal was also clearly shown. These preoperative findings are very useful to plan the extent to which the internal auditory canal can be opened, and for intraoperative identification of the nerves in the canal. MR cisternography is less invasive since no contrast material or radiation is required, as with thin-slice high-resolution computed tomography (CT). MR cisternography should replace high-resolution CT for the preoperative neuroradiological evaluation of vestibular schwannoma. (author)
A Fast Measuring Method for the Inner Diameter of Coaxial Holes.
Wang, Lei; Yang, Fangyun; Fu, Luhua; Wang, Zhong; Yang, Tongyu; Liu, Changjie
2017-03-22
A new method for fast diameter measurement of coaxial holes is studied. The paper describes a multi-layer measuring rod that installs a single laser displacement sensor (LDS) on each layer. This method is easy to implement by rotating the measuring rod, and immune from detecting the measuring rod's rotation angles, so all diameters of coaxial holes can be calculated by sensors' values. While revolving, the changing angles of each sensor's laser beams are approximately equal in the rod's radial direction so that the over-determined nonlinear equations of multi-layer holes for fitting circles can be established. The mathematical model of the measuring rod is established, all parameters that affect the accuracy of measurement are analyzed and simulated. In the experiment, the validity of the method is verified, the inner diameter measuring precision of 28 μm is achieved by 20 μm linearity LDS. The measuring rod has advantages of convenient operation and easy manufacture, according to the actual diameters of coaxial holes, and also the varying number of holes, LDS's mounting location can be adjusted for different parts. It is convenient for rapid diameter measurement in industrial use.
A fast combination method in DSmT and its application to recommender system.
Directory of Open Access Journals (Sweden)
Yilin Dong
Full Text Available In many applications involving epistemic uncertainties usually modeled by belief functions, it is often necessary to approximate general (non-Bayesian basic belief assignments (BBAs to subjective probabilities (called Bayesian BBAs. This necessity occurs if one needs to embed the fusion result in a system based on the probabilistic framework and Bayesian inference (e.g. tracking systems, or if one needs to make a decision in the decision making problems. In this paper, we present a new fast combination method, called modified rigid coarsening (MRC, to obtain the final Bayesian BBAs based on hierarchical decomposition (coarsening of the frame of discernment. Regarding this method, focal elements with probabilities are coarsened efficiently to reduce computational complexity in the process of combination by using disagreement vector and a simple dichotomous approach. In order to prove the practicality of our approach, this new approach is applied to combine users' soft preferences in recommender systems (RSs. Additionally, in order to make a comprehensive performance comparison, the proportional conflict redistribution rule #6 (PCR6 is regarded as a baseline in a range of experiments. According to the results of experiments, MRC is more effective in accuracy of recommendations compared to original Rigid Coarsening (RC method and comparable in computational time.
Directory of Open Access Journals (Sweden)
Xin Li
2015-01-01
Full Text Available DNA or gene signal detection is of great significance in many fields including medical examination, intracellular molecular monitoring, and gene disease signal diagnosis, but detection of DNA or gene signals in a low concentration with instant visual results remains a challenge. In this work, a universal fast and visual colorimetric detection method for DNA signals is proposed. Specifically, a DNA signal amplification “circuit” based on DNA strand displacement is firstly designed to amplify the target DNA signals, and then thiol modified hairpin DNA strands and gold nanoparticles are used to make signal detection results visualized in a colorimetric manner. If the target DNA signal exists, the gold nanoparticles aggregate and settle down with color changing from dark red to grey quickly; otherwise, the gold nanoparticles’ colloids remain stable in dark red. The proposed method provides a novel way to detect quickly DNA or gene signals in low concentrations with instant visual results. When applied in real-life, it may provide a universal colorimetric method for gene disease signal diagnosis.
Fast and accurate denoising method applied to very high resolution optical remote sensing images
Masse, Antoine; Lefèvre, Sébastien; Binet, Renaud; Artigues, Stéphanie; Lassalle, Pierre; Blanchet, Gwendoline; Baillarin, Simon
2017-10-01
Restoration of Very High Resolution (VHR) optical Remote Sensing Image (RSI) is critical and leads to the problem of removing instrumental noise while keeping integrity of relevant information. Improving denoising in an image processing chain implies increasing image quality and improving performance of all following tasks operated by experts (photo-interpretation, cartography, etc.) or by algorithms (land cover mapping, change detection, 3D reconstruction, etc.). In a context of large industrial VHR image production, the selected denoising method should optimized accuracy and robustness with relevant information and saliency conservation, and rapidity due to the huge amount of data acquired and/or archived. Very recent research in image processing leads to a fast and accurate algorithm called Non Local Bayes (NLB) that we propose to adapt and optimize for VHR RSIs. This method is well suited for mass production thanks to its best trade-off between accuracy and computational complexity compared to other state-of-the-art methods. NLB is based on a simple principle: similar structures in an image have similar noise distribution and thus can be denoised with the same noise estimation. In this paper, we describe in details algorithm operations and performances, and analyze parameter sensibilities on various typical real areas observed in VHR RSIs.
Gao, WenZhi; Li, ZhuFei; Yang, JiMing
2015-10-01
A hybrid CFD/characteristic method (CCM) was proposed for fast design and evaluation of hypersonic inlet flow with nose bluntness, which targets the combined advantages of CFD and method of characteristics. Both the accuracy and efficiency of the developed CCM were verified reliably, and it was well demonstrated for the external surfaces design of a hypersonic forebody/inlet with nose bluntness. With the help of CCM method, effects of nose bluntness on forebody shock shapes and the flowfield qualities which dominate inlet performance were examined and analyzed on the two-dimensional and axisymmetric configurations. The results showed that blunt effects of a wedge forebody are more substantial than that of related cone cases. For a conical forebody with a properly blunted nose, a recovery of the shock front back to that of corresponding sharp nose is exhibited, accompanied with a gradually fading out of entropy layer effects. Consequently a simplification is thought to be reasonable for an axisymmetric inlet with a proper compression angle, and a blunt nose of limited radius can be idealized as a sharp nose, as the spillage and flow variations at the entrance are negligible, even though the nose scale increases to 10% cowl lip radius. Whereas for two-dimensional inlets, the blunt effects are substantial since not only the inlet capturing/starting capabilities, but also the flow uniformities are obviously degraded.
de Andrade, Jucimara Kulek; de Andrade, Camila Kulek; Komatsu, Emy; Perreault, Hélène; Torres, Yohandra Reyes; da Rosa, Marcos Roberto; Felsner, Maria Lurdes
2017-08-01
Corn syrups, important ingredients used in food and beverage industries, often contain high levels of 5-hydroxymethyl-2-furfural (HMF), a toxic contaminant. In this work, an in house validation of a difference spectrophotometric method for HMF analysis in corn syrups was developed using sophisticated statistical tools by the first time. The methodology showed excellent analytical performance with good selectivity, linearity (R 2 =99.9%, r>0.99), accuracy and low limits (LOD=0.10mgL -1 and LOQ=0.34mgL -1 ). An excellent precision was confirmed by repeatability (RSD (%)=0.30) and intermediate precision (RSD (%)=0.36) estimates and by Horrat value (0.07). A detailed study of method precision using a nested design demonstrated that variation sources such as instruments, operators and time did not interfere in the variability of results within laboratory and consequently in its intermediate precision. The developed method is environmentally friendly, fast, cheap and easy to implement resulting in an attractive alternative for corn syrups quality control in industries and official laboratories. Copyright © 2017 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Bellinger, F.O.; Winslow, G.H.
1980-12-01
Nondestructive assay (NDA) methods, principally passive gamma measurements and active neutron interrogation, have been studied for their safeguards effectiveness and programmatic impact as tools for making inventories of highly enriched uranium fast critical assembly fuel plates. It was concluded that no NDA method is the sole answer to the safeguards problem, that each of those emphasized here has its place in an integrated safeguards system, and that each has minimum facility impact. It was found that the 185-keV area, as determined with a NaI detector, was independent of highly-enriched uranium (HEU) plate irradiation history, though the random neutron driver methods used here did not permit accurate assay of irradiated plates. Containment procedures most effective for accurate assaying were considered, and a particular geometry is recommended for active interrogation by a random driver. A model, pertinent to that geometry, which relates the effects of multiplication and self-absorption, is described. Probabilities of failing to detect that plates are missing are examined
Combining the multilevel fast multipole method with the uniform geometrical theory of diffraction
Directory of Open Access Journals (Sweden)
A. Tzoulis
2005-01-01
Full Text Available The presence of arbitrarily shaped and electrically large objects in the same environment leads to hybridization of the Method of Moments (MoM with the Uniform Geometrical Theory of Diffraction (UTD. The computation and memory complexity of the MoM solution is improved with the Multilevel Fast Multipole Method (MLFMM. By expanding the k-space integrals in spherical harmonics, further considerable amount of memory can be saved without compromising accuracy and numerical speed. However, until now MoM-UTD hybrid methods are restricted to conventional MoM formulations only with Electric Field Integral Equation (EFIE. In this contribution, a MLFMM-UTD hybridization for Combined Field Integral Equation (CFIE is proposed and applied within a hybrid Finite Element - Boundary Integral (FEBI technique. The MLFMM-UTD hybridization is performed at the translation procedure on the various levels of the MLFMM, using a far-field approximation of the corresponding translation operator. The formulation of this new hybrid technique is presented, as well as numerical results.
Fast solution of neutron diffusion problem by reduced basis finite element method
International Nuclear Information System (INIS)
Chunyu, Zhang; Gong, Chen
2018-01-01
Highlights: •An extremely efficient method is proposed to solve the neutron diffusion equation with varying the cross sections. •Three orders of speedup is achieved for IAEA benchmark problems. •The method may open a new possibility of efficient high-fidelity modeling of large scale problems in nuclear engineering. -- Abstract: For the important applications which need carry out many times of neutron diffusion calculations such as the fuel depletion analysis and the neutronics-thermohydraulics coupling analysis, fast and accurate solutions of the neutron diffusion equation are demanding but necessary. In the present work, the certified reduced basis finite element method is proposed and implemented to solve the generalized eigenvalue problems of neutron diffusion with variable cross sections. The order reduced model is built upon high-fidelity finite element approximations during the offline stage. During the online stage, both the k eff and the spatical distribution of neutron flux can be obtained very efficiently for any given set of cross sections. Numerical tests show that a speedup of around 1100 is achieved for the IAEA two-dimensional PWR benchmark problem and a speedup of around 3400 is achieved for the three-dimensional counterpart with the fission cross-sections, the absorption cross-sections and the scattering cross-sections treated as parameters.
A fast all-in-one method for automated post-processing of PIV data.
Garcia, Damien
2011-05-01
Post-processing of PIV (particle image velocimetry) data typically contains three following stages: validation of the raw data, replacement of spurious and missing vectors, and some smoothing. A robust post-processing technique that carries out these steps simultaneously is proposed. The new all-in-one method (DCT-PLS), based on a penalized least squares approach (PLS), combines the use of the discrete cosine transform (DCT) and the generalized cross-validation, thus allowing fast unsupervised smoothing of PIV data. The DCT-PLS was compared with conventional methods, including the normalized median test, for post-processing of simulated and experimental raw PIV velocity fields. The DCT-PLS was shown to be more efficient than the usual methods, especially in the presence of clustered outliers. It was also demonstrated that the DCT-PLS can easily deal with a large amount of missing data. Because the proposed algorithm works in any dimension, the DCT-PLS is also suitable for post-processing of volumetric three-component PIV data.
A fast all-in-one method for automated post-processing of PIV data
Garcia, Damien
2013-01-01
Post-processing of PIV (particle image velocimetry) data typically contains three following stages: validation of the raw data, replacement of spurious and missing vectors, and some smoothing. A robust post-processing technique that carries out these steps simultaneously is proposed. The new all-in-one method (DCT-PLS), based on a penalized least squares approach (PLS), combines the use of the discrete cosine transform (DCT) and the generalized cross-validation, thus allowing fast unsupervised smoothing of PIV data. The DCT-PLS was compared with conventional methods, including the normalized median test, for post-processing of simulated and experimental raw PIV velocity fields. The DCT-PLS was shown to be more efficient than the usual methods, especially in the presence of clustered outliers. It was also demonstrated that the DCT-PLS can easily deal with a large amount of missing data. Because the proposed algorithm works in any dimension, the DCT-PLS is also suitable for post-processing of volumetric three-component PIV data. PMID:24795497
International Nuclear Information System (INIS)
Tullett, J.D.
1990-01-01
P Benoist has developed a method for calculating cross-sections for Fast Reactor control rods and their followers described by a single homogenised region (the Equivalent Parameter Method). When used in a diffusion theory calculation, these equivalent cross-sections should give the same rod worth as one would obtain from a transport theory calculation with a heterogeneous description of the control rod and the follower. In this report, Benoist's theory is described, and a comprehensive set of tests is presented. These tests show that the method gives very good results over a range of geometries and control rod positions for a model fast reactor core. (author)
GOSSIP: a method for fast and accurate global alignment of protein structures.
Kifer, I; Nussinov, R; Wolfson, H J
2011-04-01
The database of known protein structures (PDB) is increasing rapidly. This results in a growing need for methods that can cope with the vast amount of structural data. To analyze the accumulating data, it is important to have a fast tool for identifying similar structures and clustering them by structural resemblance. Several excellent tools have been developed for the comparison of protein structures. These usually address the task of local structure alignment, an important yet computationally intensive problem due to its complexity. It is difficult to use such tools for comparing a large number of structures to each other at a reasonable time. Here we present GOSSIP, a novel method for a global all-against-all alignment of any set of protein structures. The method detects similarities between structures down to a certain cutoff (a parameter of the program), hence allowing it to detect similar structures at a much higher speed than local structure alignment methods. GOSSIP compares many structures in times which are several orders of magnitude faster than well-known available structure alignment servers, and it is also faster than a database scanning method. We evaluate GOSSIP both on a dataset of short structural fragments and on two large sequence-diverse structural benchmarks. Our conclusions are that for a threshold of 0.6 and above, the speed of GOSSIP is obtained with no compromise of the accuracy of the alignments or of the number of detected global similarities. A server, as well as an executable for download, are available at http://bioinfo3d.cs.tau.ac.il/gossip/.
Calculation of the fast multiplication factor by the fission matrix method
International Nuclear Information System (INIS)
Naumov, V.A.; Rozin, S.G.; Ehl'perin, T.I.
1976-01-01
A variation of the Monte Carlo method to calculate an effective breeding factor of a nuclear reactor is described. The evaluation procedure of reactivity perturbations by the Monte Carlo method in the first order perturbation theory is considered. The method consists in reducing an integral neutron transport equation to a set of linear algebraic equations. The coefficients of this set are elements of a fission matrix. The fission matrix being a Grin function of the neutron transport equation, is evaluated by the Monte Carlo method. In the program realizing the suggested algorithm, the game for initial neutron energy of a fission spectrum and then for the region of neutron birth, ΔVsub(f)sup(i)has been played in proportion to the product of Σsub(f)sup(i)ΔVsub(f)sup(i), where Σsub(f)sup(i) is a macroscopic cross section in the region numbered at the birth energy. Further iterations of a space distribution of neutrons in the system are performed by the generation method. In the adopted scheme of simulation of neutron histories the emission of secondary neutrons is controlled by weights; it occurs at every collision and not only in the end on the history. The breeding factor is calculated simultaneously with the space distribution of neutron worth in the system relative to the fission process and neutron flux. Efficiency of the described procedure has been tested on the calculation of the breeding factor for the Godiva assembly, simulating a fast reactor with a hard spectrum. A high accuracy of calculations at moderate number of zones in the core and reasonable statistics has been stated
Method-centered digital communities on protocols.io for fast-paced scientific innovation.
Kindler, Lori; Stoliartchouk, Alexei; Teytelman, Leonid; Hurwitz, Bonnie L
2016-01-01
The Internet has enabled online social interaction for scientists beyond physical meetings and conferences. Yet despite these innovations in communication, dissemination of methods is often relegated to just academic publishing. Further, these methods remain static, with subsequent advances published elsewhere and unlinked. For communities undergoing fast-paced innovation, researchers need new capabilities to share, obtain feedback, and publish methods at the forefront of scientific development. For example, a renaissance in virology is now underway given the new metagenomic methods to sequence viral DNA directly from an environment. Metagenomics makes it possible to "see" natural viral communities that could not be previously studied through culturing methods. Yet, the knowledge of specialized techniques for the production and analysis of viral metagenomes remains in a subset of labs. This problem is common to any community using and developing emerging technologies and techniques. We developed new capabilities to create virtual communities in protocols.io, an open access platform, for disseminating protocols and knowledge at the forefront of scientific development. To demonstrate these capabilities, we present a virology community forum called VERVENet. These new features allow virology researchers to share protocols and their annotations and optimizations, connect with the broader virtual community to share knowledge, job postings, conference announcements through a common online forum, and discover the current literature through personalized recommendations to promote discussion of cutting edge research. Virtual communities in protocols.io enhance a researcher's ability to: discuss and share protocols, connect with fellow community members, and learn about new and innovative research in the field. The web-based software for developing virtual communities is free to use on protocols.io. Data are available through public APIs at protocols.io.
Koulman, A; Bos, R; Medarde, M; Pras, N; Quax, WJ
2001-01-01
A new GC-MS method for monitoring lignans was developed to study the variation in plants and elucidate the biosynthetic steps. A simple and fast extraction procedure for lyophilised plant material was developed, giving a lignan-rich extract. A GC-MS method was set up using an apolar WCOT fused
International Nuclear Information System (INIS)
Teymourtash, A. R.; Mahpeykar, M. R.
2003-01-01
During the course of expansion in turbines, the steam at first super cools and then nucleated to become a two-phase mixture. This is an area where greater understanding can lead to improved design. This paper describes a numerical method for the solution of two-dimensional two-phase flow of steam in a cascade of turbine blading; the unsteady euler equations governing the overall behaviour of the fluid are combined with equations describing droplet behaviour and treated by Jasmine fourth order runge Kutta time marching scheme which modified to allow for two-phase effects. The theoretical surface pressure distributions, droplet radii and contours of constant wetness fraction are presented and results are discussed in the light of knowledge of actual surface pressure distributions
Fast and "green" method for the analytical monitoring of haloketones in treated water.
Serrano, María; Silva, Manuel; Gallego, Mercedes
2014-09-05
Several groups of organic compounds have emerged as being particularly relevant as environmental pollutants, including disinfection by-products (DBPs). Haloketones (HKs), which belong to the unregulated volatile fraction of DBPs, have become a priority because of their occurrence in drinking water at concentrations below 1μg/L. The absence of a comprehensive method for HKs has led to the development of the first method for determining fourteen of these species. In an effort to miniaturise, this study develops a micro liquid-liquid extraction (MLLE) method adapted from EPA Method 551.1. In this method practically, the whole extract (50μL) was injected into a programmed temperature vaporiser-gas chromatography-mass spectrometer in order to improve sensitivity. The method was validated by comparing it to EPA Method 551.1 and showed relevant advantages such as: lower sample pH (1.5), higher aqueous/organic volume ratio (60), lower solvent consumption (200μL) and fast and cost-saving operation. The MLLE method achieved detection limits ranging from 6 to 60ng/L (except for 1,1,3-tribromo-3-chloroacetone, 120ng/L) with satisfactory precision (RSD, ∼6%) and high recoveries (95-99%). An evaluation was carried out of the influence of various dechlorinating agents as well as of the sample pH on the stability of the fourteen HKs in treated water. To ensure the HKs integrity for at least 1 week during storage at 4°C, the samples were acidified at pH ∼1.5, which coincides with the sample pH required for MLLE. The green method was applied to the speciation of fourteen HKs in tap and swimming pool waters, where one and seven chlorinated species, respectively, were found. The concentration of 1.1-dichloroacetone in swimming pool water increased ∼25 times in relation to tap water. Copyright © 2014 Elsevier B.V. All rights reserved.
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Titanium
American Society for Testing and Materials. Philadelphia
2008-01-01
1.1 This test method covers procedures for measuring reaction rates by the activation reactions 46Ti(n,p) 46Sc + 47Ti(n, np)46Sc. Note 1—Since the cross section for the (n,np) reaction is relatively small for energies less than 12 MeV and is not easily distinguished from that of the (n,p) reaction, this test method will refer to the (n,p) reaction only. 1.2 The reaction is useful for measuring neutrons with energies above approximately 4.4 MeV and for irradiation times up to about 250 days (for longer irradiations, see Practice E 261). 1.3 With suitable techniques, fission-neutron fluence rates above 109 cm–2·s–1 can be determined. However, in the presence of a high thermal-neutron fluence rate, 46Sc depletion should be investigated. 1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all...
Chemical methods for the use of niobium from pressure vessel cladding as a fast neutron dosimeter
International Nuclear Information System (INIS)
Karnani, Hari
1986-08-01
the steel samples from the cladding of a pressure vessel of an operating nuclear power reactor were obtained by scraping. The cladding material of the pressure vessel contained about 0.5 % niobium. It was desired to use the niobium as a dosimeter for estimating fast fluences at the pressure vessel. The weak radiation from the reaction product 93m Nb cannot be measured in the presence of other elements and interfering activities. A method was developed to separate niobium from other metals present; the concentration and yield of niobium were determined spectrophotometrically. The irradiated niobium was electrodeposited from aqueous solutions on copper discs. The amount of the deposited niobium was determined by a radiochemical method which makes use of its own radioactivity - measured with a liquid scintillation counter - and the known starting mass of niobium. It was possible to determine the deposited niobium masses (5 to 200 microgram) with a desired degree of accuracy. The absolute emission rate of X-rays could then be measured without any self-absorption or interference from other activities. The mass of niobium on each preparate and its X-ray emission rate, later on, were used as basic experimental data for the estimation of last neutron doses at the pressure vessel
Petascale molecular dynamics simulation using the fast multipole method on K computer
Ohno, Yousuke; Yokota, Rio; Koyama, Hiroshi; Morimoto, Gentaro; Hasegawa, Aki; Masumoto, Gen; Okimoto, Noriaki; Hirano, Yoshinori; Ibeid, Huda; Narumi, Tetsu; Taiji, Makoto
2014-01-01
In this paper, we report all-atom simulations of molecular crowding - a result from the full node simulation on the "K computer", which is a 10-PFLOPS supercomputer in Japan. The capability of this machine enables us to perform simulation of crowded cellular environments, which are more realistic compared to conventional MD simulations where proteins are simulated in isolation. Living cells are "crowded" because macromolecules comprise ∼30% of their molecular weight. Recently, the effects of crowded cellular environments on protein stability have been revealed through in-cell NMR spectroscopy. To measure the performance of the "K computer", we performed all-atom classical molecular dynamics simulations of two systems: target proteins in a solvent, and target proteins in an environment of molecular crowders that mimic the conditions of a living cell. Using the full system, we achieved 4.4 PFLOPS during a 520 million-atom simulation with cutoff of 28 Å. Furthermore, we discuss the performance and scaling of fast multipole methods for molecular dynamics simulations on the "K computer", as well as comparisons with Ewald summation methods. © 2014 Elsevier B.V. All rights reserved.
De Nicola, F; Concha Graña, E; Aboal, J R; Carballeira, A; Fernández, J Á; López Mahía, P; Prada Rodríguez, D; Muniategui Lorenzo, S
2016-06-01
Due to the complexity and heterogeneity of plant matrices, new procedure should be standardized for each single biomonitor. Thus, here is described a matrix solid-phase dispersion extraction method, previously used for moss samples, improved and modified for the analyses of PAHs in Quercus robur leaves and Pinus pinaster needles, species widely used in biomonitoring studies across Europe. The improvements compared to the previous procedure are the use of Florisil added with further clean-up sorbents, 10% deactivated silica for pine needles and PSA for oak leaves, being these matrices rich in interfering compounds, as shown by the gas chromatography-mass spectrometry analyses acquired in full scan mode. Good trueness, with values in the range 90-120% for the most of compounds, high precision (intermediate precision between 2% and 12%) and good sensitivity using only 250mg of samples (limits of quantification lower than 3 and 1.5ngg(-1), respectively for pine and oak) were achieved by the selected procedures. These methods proved to be reliable for PAH analyses and, having advantage of fastness, can be used in biomonitoring studies of PAH air contamination. Copyright © 2016 Elsevier B.V. All rights reserved.
A fast and robust method for automated analysis of axonal transport.
Welzel, Oliver; Knörr, Jutta; Stroebel, Armin M; Kornhuber, Johannes; Groemer, Teja W
2011-09-01
Cargo movement along axons and dendrites is indispensable for the survival and maintenance of neuronal networks. Key parameters of this transport such as particle velocities and pausing times are often studied using kymograph construction, which converts the transport along a line of interest from a time-lapse movie into a position versus time image. Here we present a method for the automatic analysis of such kymographs based on the Hough transform, which is a robust and fast technique to extract lines from images. The applicability of the method was tested on simulated kymograph images and real data from axonal transport of synaptophysin and tetanus toxin as well as the velocity analysis of synaptic vesicle sharing between adjacent synapses in hippocampal neurons. Efficiency analysis revealed that the algorithm is able to detect a wide range of velocities and can be used at low signal-to-noise ratios. The present work enables the quantification of axonal transport parameters with high throughput with no a priori assumptions and minimal human intervention.
International Nuclear Information System (INIS)
Okuno, Hiroshi; Fujine, Yukio; Asakura, Toshihide; Murazaki, Minoru; Koyama, Tomozo; Sakakibara, Tetsuro; Shibata, Atsuhiro
1999-03-01
The crystallization method is proposed to apply for recovery of uranium from dissolution liquid, enabling to reduce handling materials in later stages of reprocessing used fast breeder reactor (FBR) fuels. This report studies possible safety problems accompanied by the proposed method. Crystallization process was first defined in the whole reprocessing process, and the quantity and the kind of treated fuel were specified. Possible problems, such as criticality, shielding, fire/explosion, and confinement, were then investigated; and the events that might induce accidental incidents were discussed. Criticality, above all the incidents, was further studied by considering exampled criticality control of the crystallization process. For crystallization equipment, in particular, evaluation models were set up in normal and accidental operation conditions. Related data were selected out from the nuclear criticality safety handbooks. The theoretical densities of plutonium nitrates, which give basic and important information, were estimated in this report based on the crystal structure data. The criticality limit of crystallization equipment was calculated based on the above information. (author)
Petascale molecular dynamics simulation using the fast multipole method on K computer
Ohno, Yousuke
2014-10-01
In this paper, we report all-atom simulations of molecular crowding - a result from the full node simulation on the "K computer", which is a 10-PFLOPS supercomputer in Japan. The capability of this machine enables us to perform simulation of crowded cellular environments, which are more realistic compared to conventional MD simulations where proteins are simulated in isolation. Living cells are "crowded" because macromolecules comprise ∼30% of their molecular weight. Recently, the effects of crowded cellular environments on protein stability have been revealed through in-cell NMR spectroscopy. To measure the performance of the "K computer", we performed all-atom classical molecular dynamics simulations of two systems: target proteins in a solvent, and target proteins in an environment of molecular crowders that mimic the conditions of a living cell. Using the full system, we achieved 4.4 PFLOPS during a 520 million-atom simulation with cutoff of 28 Å. Furthermore, we discuss the performance and scaling of fast multipole methods for molecular dynamics simulations on the "K computer", as well as comparisons with Ewald summation methods. © 2014 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Kobayashi, Shinji; Sakasai, Akira; Koide, Yoshihiko; Sakamoto, Yoshiteru; Kamada, Yutaka; Hatae, Takaki; Oyama, Naoyuki; Miura, Yukitoshi
2003-01-01
Recent developments and results of fast charge exchange recombination spectroscopy (CXRS) using interference filter method are reported. In order to measure the rapid change of the ion temperature and rotation velocity under collapse or transition phenomena with high-time resolution, two types of interference filter systems were applied to the CXRS diagnostics on the JT-60U Tokamak. One can determine the Doppler broadening and Doppler shift of the CXR emission using three interference filters having slightly different center wavelengths. A rapid estimation method of the temperature ad rotation velocity without non-linear least square fitting is presented. The modification of the three-filters system enables us to improve the minimum time resolution up to 0.8 ms, which is better than that of 16.7 ms for the conventional CXRS system using the CCD detector in JT-60U. The other system having seven wavelength channels is newly fabricated to crosscheck the results obtained by the three-filters assembly, that is, to verify that the CXR emission forms a Gaussian profile under collapse phenomena. In a H-mode discharge having giant edge localized modes, the results obtained by the two systems are compared. The applicability of the three-filters system to the measurement of rapid changes in temperature and rotation velocity is demonstrated. (author)
Quéméner, Bernard; Bertrand, Dominique; Marty, Isabelle; Causse, Mathilde; Lahaye, Marc
2007-02-02
The variability in the chemistry of cell wall polysaccharides in pericarp tissue of red-ripe tomato fruit (Solanum lycopersicon Mill.) was characterized by chemical methods and enzymatic degradations coupled to high performance anion exchange chromatography (HPAEC) and mass spectrometry analysis. Large fruited line, Levovil (LEV) carrying introgressed chromosome fragments from a cherry tomato line Cervil (CER) on chromosomes 4 (LC4), 9 (LC9), or on chromosomes 1, 2, 4 and 9 (LCX) and containing quantitative trait loci (QTLs) for texture traits, was studied. In order to differentiate cell wall polysaccharide modifications in the tomato fruit collection by multivariate analysis, chromatograms were corrected for baseline drift and shift of the component elution time using an approach derived from image analysis and mathematical morphology. The baseline was first corrected by using a "moving window" approach while the peak-matching method developed was based upon location of peaks as local maxima within a window of a definite size. The fast chromatographic data preprocessing proposed was a prerequisite for the different chemometric treatments, such as variance and principal component analysis applied herein to the analysis. Applied to the tomato collection, the combined enzymatic degradations and HPAEC analyses revealed that the firm LCX and CER genotypes showed a higher proportion of glucuronoxylans and pectic arabinan side chains while the mealy LC9 genotype demonstrated the highest content of pectic galactan side chains. QTLs on tomato chromosomes 1, 2, 4 and 9 contain important genes controlling glucuronoxylan and pectic neutral side chains biosynthesis and/or metabolism.
Direct infusion-SIM as fast and robust method for absolute protein quantification in complex samples
Directory of Open Access Journals (Sweden)
Christina Looße
2015-06-01
Full Text Available Relative and absolute quantification of proteins in biological and clinical samples are common approaches in proteomics. Until now, targeted protein quantification is mainly performed using a combination of HPLC-based peptide separation and selected reaction monitoring on triple quadrupole mass spectrometers. Here, we show for the first time the potential of absolute quantification using a direct infusion strategy combined with single ion monitoring (SIM on a Q Exactive mass spectrometer. By using complex membrane fractions of Escherichia coli, we absolutely quantified the recombinant expressed heterologous human cytochrome P450 monooxygenase 3A4 (CYP3A4 comparing direct infusion-SIM with conventional HPLC-SIM. Direct-infusion SIM revealed only 14.7% (±4.1 (s.e.m. deviation on average, compared to HPLC-SIM and a decreased processing and analysis time of 4.5 min (that could be further decreased to 30 s for a single sample in contrast to 65 min by the LC–MS method. Summarized, our simplified workflow using direct infusion-SIM provides a fast and robust method for quantification of proteins in complex protein mixtures.
PETSTEP: Generation of synthetic PET lesions for fast evaluation of segmentation methods
Berthon, Beatrice; Häggström, Ida; Apte, Aditya; Beattie, Bradley J.; Kirov, Assen S.; Humm, John L.; Marshall, Christopher; Spezi, Emiliano; Larsson, Anne; Schmidtlein, C. Ross
2016-01-01
Purpose This work describes PETSTEP (PET Simulator of Tracers via Emission Projection): a faster and more accessible alternative to Monte Carlo (MC) simulation generating realistic PET images, for studies assessing image features and segmentation techniques. Methods PETSTEP was implemented within Matlab as open source software. It allows generating three-dimensional PET images from PET/CT data or synthetic CT and PET maps, with user-drawn lesions and user-set acquisition and reconstruction parameters. PETSTEP was used to reproduce images of the NEMA body phantom acquired on a GE Discovery 690 PET/CT scanner, and simulated with MC for the GE Discovery LS scanner, and to generate realistic Head and Neck scans. Finally the sensitivity (S) and Positive Predictive Value (PPV) of three automatic segmentation methods were compared when applied to the scanner-acquired and PETSTEP-simulated NEMA images. Results PETSTEP produced 3D phantom and clinical images within 4 and 6 min respectively on a single core 2.7 GHz computer. PETSTEP images of the NEMA phantom had mean intensities within 2% of the scanner-acquired image for both background and largest insert, and 16% larger background Full Width at Half Maximum. Similar results were obtained when comparing PETSTEP images to MC simulated data. The S and PPV obtained with simulated phantom images were statistically significantly lower than for the original images, but led to the same conclusions with respect to the evaluated segmentation methods. Conclusions PETSTEP allows fast simulation of synthetic images reproducing scanner-acquired PET data and shows great promise for the evaluation of PET segmentation methods. PMID:26321409
Liska, Sebastian; Colonius, Tim
2017-02-01
A new parallel, computationally efficient immersed boundary method for solving three-dimensional, viscous, incompressible flows on unbounded domains is presented. Immersed surfaces with prescribed motions are generated using the interpolation and regularization operators obtained from the discrete delta function approach of the original (Peskin's) immersed boundary method. Unlike Peskin's method, boundary forces are regarded as Lagrange multipliers that are used to satisfy the no-slip condition. The incompressible Navier-Stokes equations are discretized on an unbounded staggered Cartesian grid and are solved in a finite number of operations using lattice Green's function techniques. These techniques are used to automatically enforce the natural free-space boundary conditions and to implement a novel block-wise adaptive grid that significantly reduces the run-time cost of solutions by limiting operations to grid cells in the immediate vicinity and near-wake region of the immersed surface. These techniques also enable the construction of practical discrete viscous integrating factors that are used in combination with specialized half-explicit Runge-Kutta schemes to accurately and efficiently solve the differential algebraic equations describing the discrete momentum equation, incompressibility constraint, and no-slip constraint. Linear systems of equations resulting from the time integration scheme are efficiently solved using an approximation-free nested projection technique. The algebraic properties of the discrete operators are used to reduce projection steps to simple discrete elliptic problems, e.g. discrete Poisson problems, that are compatible with recent parallel fast multipole methods for difference equations. Numerical experiments on low-aspect-ratio flat plates and spheres at Reynolds numbers up to 3700 are used to verify the accuracy and physical fidelity of the formulation.
A fast running method for predicting the efficiency of core melt spreading for application in ASTEC
International Nuclear Information System (INIS)
Spengler, C.
2010-01-01
The integral Accident Source Term Evaluation Code (ASTEC) is jointly developed by the French Institut de Radioprotection et de Surete Nucleaire (IRSN) and the German Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH to simulate the complete scenario of a hypothetical severe accident in a nuclear light water reactor, from the initial event until the possible radiological release of fission products out of the containment. In the frame of the new series of ASTEC V2 versions appropriate model extensions to the European Pressurised Water Reactor (EPR) are under development. With view to assessing with ASTEC the proper operation of the ex-vessel melt retention and coolability concept of the EPR with regard to melt spreading an approximation of the area finally covered by the corium and of the distance run by the corium front before freezing is required. A necessary capability of ASTEC is in a first step to identify such boundary cases, for which there is a potential that the melt will freeze before the spreading area is completely filled. This paper presents a fast running method for estimating the final extent of the area covered with melt on which a simplified criterion in ASTEC for detecting such boundary cases will be based. If a boundary case is detected the application of a more-detailed method might be necessary to assess further the consequences for the accident sequence. The major objective here is to provide a reliable method for estimating the final result of the spreading and not to provide highly detailed methods to simulate the dynamics of the transient process. (orig.)
Cazorla, Constantin; Morel, Thierry; Nazé, Yaël; Rauw, Gregor; Semaan, Thierry; Daflon, Simone; Oey, M. S.
2017-07-01
Aims: Recent observations have challenged our understanding of rotational mixing in massive stars by revealing a population of fast-rotating objects with apparently normal surface nitrogen abundances. However, several questions have arisen because of a number of issues, which have rendered a reinvestigation necessary; these issues include the presence of numerous upper limits for the nitrogen abundance, unknown multiplicity status, and a mix of stars with different physical properties, such as their mass and evolutionary state, which are known to control the amount of rotational mixing. Methods: We have carefully selected a large sample of bright, fast-rotating early-type stars of our Galaxy (40 objects with spectral types between B0.5 and O4). Their high-quality, high-resolution optical spectra were then analysed with the stellar atmosphere modelling codes DETAIL/SURFACE or CMFGEN, depending on the temperature of the target. Several internal and external checks were performed to validate our methods; notably, we compared our results with literature data for some well-known objects, studied the effect of gravity darkening, or confronted the results provided by the two codes for stars amenable to both analyses. Furthermore, we studied the radial velocities of the stars to assess their binarity. Results: This first part of our study presents our methods and provides the derived stellar parameters, He, CNO abundances, and the multiplicity status of every star of the sample. It is the first time that He and CNO abundances of such a large number of Galactic massive fast rotators are determined in a homogeneous way. Based on observations obtained with the Heidelberg Extended Range Optical Spectrograph (HEROS) at the Telescopio Internacional de Guanajuato (TIGRE) with the SOPHIE échelle spectrograph at the Haute-Provence Observatory (OHP; Institut Pytheas; CNRS, France), and with the Magellan Inamori Kyocera Echelle (MIKE) spectrograph at the Magellan II Clay telescope
Areva fatigue concept. Fast fatigue evaluation, a new method for fatigue analysis
International Nuclear Information System (INIS)
Heinz, Benedikt; Bergholz, Steffen; Rudolph, Juergen
2011-01-01
Within the discussions on the long term operation (LTO) of nuclear power plants the ageing management is on the focus of that analysis. The knowledge of the operational thermal cyclic load data on components of the power plants and their evaluation in the fatigue analysis is a central concern. The changes in fatigue requirements (e.g. the consideration of environmentally assisted fatigue - EAF) recently discussed and LTO efforts are a strong motivation for the identification of margins in the existing fatigue analysis approaches. These margins should be considered within new approaches in order to obtain realistic (or more accurate) analysis results. Of course, these new analysis approaches have to be manageable and efficient. The Areva Fatigue Concept (AFC) offers the comprehensive conceptual basis for the consideration of fatigue on different levels and depths. The combination of data logging and automated fatigue evaluation are important modules of the AFC. Besides the established simplified stress based fatigue estimation Areva develops a further automated fatigue analysis method called Fast Fatigue Evaluation (FFE). This method comprises highly automated stress analyses at the fatigue relevant locations of the component. Hence, a component specific course of stress as a function of time is determined based on FAMOS or similar temperature measurement systems. The subsequent application of the rain flow cycle counting algorithm allows for the determination of the usage factor following the rules of the design code requirements. The new FFE approach constitutes a cycle counting method based on the real stresses in the component, and determined as result a rule-conformity cumulative usage factor. (orig.)
A Fast Multiple-Kernel Method With Applications to Detect Gene-Environment Interaction.
Marceau, Rachel; Lu, Wenbin; Holloway, Shannon; Sale, Michèle M; Worrall, Bradford B; Williams, Stephen R; Hsu, Fang-Chi; Tzeng, Jung-Ying
2015-09-01
Kernel machine (KM) models are a powerful tool for exploring associations between sets of genetic variants and complex traits. Although most KM methods use a single kernel function to assess the marginal effect of a variable set, KM analyses involving multiple kernels have become increasingly popular. Multikernel analysis allows researchers to study more complex problems, such as assessing gene-gene or gene-environment interactions, incorporating variance-component based methods for population substructure into rare-variant association testing, and assessing the conditional effects of a variable set adjusting for other variable sets. The KM framework is robust, powerful, and provides efficient dimension reduction for multifactor analyses, but requires the estimation of high dimensional nuisance parameters. Traditional estimation techniques, including regularization and the "expectation-maximization (EM)" algorithm, have a large computational cost and are not scalable to large sample sizes needed for rare variant analysis. Therefore, under the context of gene-environment interaction, we propose a computationally efficient and statistically rigorous "fastKM" algorithm for multikernel analysis that is based on a low-rank approximation to the nuisance effect kernel matrices. Our algorithm is applicable to various trait types (e.g., continuous, binary, and survival traits) and can be implemented using any existing single-kernel analysis software. Through extensive simulation studies, we show that our algorithm has similar performance to an EM-based KM approach for quantitative traits while running much faster. We also apply our method to the Vitamin Intervention for Stroke Prevention (VISP) clinical trial, examining gene-by-vitamin effects on recurrent stroke risk and gene-by-age effects on change in homocysteine level. © 2015 WILEY PERIODICALS, INC.
A new fast method for inferring multiple consensus trees using k-medoids.
Tahiri, Nadia; Willems, Matthieu; Makarenkov, Vladimir
2018-04-05
Gene trees carry important information about specific evolutionary patterns which characterize the evolution of the corresponding gene families. However, a reliable species consensus tree cannot be inferred from a multiple sequence alignment of a single gene family or from the concatenation of alignments corresponding to gene families having different evolutionary histories. These evolutionary histories can be quite different due to horizontal transfer events or to ancient gene duplications which cause the emergence of paralogs within a genome. Many methods have been proposed to infer a single consensus tree from a collection of gene trees. Still, the application of these tree merging methods can lead to the loss of specific evolutionary patterns which characterize some gene families or some groups of gene families. Thus, the problem of inferring multiple consensus trees from a given set of gene trees becomes relevant. We describe a new fast method for inferring multiple consensus trees from a given set of phylogenetic trees (i.e. additive trees or X-trees) defined on the same set of species (i.e. objects or taxa). The traditional consensus approach yields a single consensus tree. We use the popular k-medoids partitioning algorithm to divide a given set of trees into several clusters of trees. We propose novel versions of the well-known Silhouette and Caliński-Harabasz cluster validity indices that are adapted for tree clustering with k-medoids. The efficiency of the new method was assessed using both synthetic and real data, such as a well-known phylogenetic dataset consisting of 47 gene trees inferred for 14 archaeal organisms. The method described here allows inference of multiple consensus trees from a given set of gene trees. It can be used to identify groups of gene trees having similar intragroup and different intergroup evolutionary histories. The main advantage of our method is that it is much faster than the existing tree clustering approaches, while
WATSFAR: numerical simulation of soil WATer and Solute fluxes using a FAst and Robust method
Crevoisier, David; Voltz, Marc
2013-04-01
To simulate the evolution of hydro- and agro-systems, numerous spatialised models are based on a multi-local approach and improvement of simulation accuracy by data-assimilation techniques are now used in many application field. The latest acquisition techniques provide a large amount of experimental data, which increase the efficiency of parameters estimation and inverse modelling approaches. In turn simulations are often run on large temporal and spatial domains which requires a large number of model runs. Eventually, despite the regular increase in computing capacities, the development of fast and robust methods describing the evolution of saturated-unsaturated soil water and solute fluxes is still a challenge. Ross (2003, Agron J; 95:1352-1361) proposed a method, solving 1D Richards' and convection-diffusion equation, that fulfil these characteristics. The method is based on a non iterative approach which reduces the numerical divergence risks and allows the use of coarser spatial and temporal discretisations, while assuring a satisfying accuracy of the results. Crevoisier et al. (2009, Adv Wat Res; 32:936-947) proposed some technical improvements and validated this method on a wider range of agro- pedo- climatic situations. In this poster, we present the simulation code WATSFAR which generalises the Ross method to other mathematical representations of soil water retention curve (i.e. standard and modified van Genuchten model) and includes a dual permeability context (preferential fluxes) for both water and solute transfers. The situations tested are those known to be the less favourable when using standard numerical methods: fine textured and extremely dry soils, intense rainfall and solute fluxes, soils near saturation, ... The results of WATSFAR have been compared with the standard finite element model Hydrus. The analysis of these comparisons highlights two main advantages for WATSFAR, i) robustness: even on fine textured soil or high water and solute
A fast 4D cone beam CT reconstruction method based on the OSC-TV algorithm.
Mascolo-Fortin, Julia; Matenine, Dmitri; Archambault, Louis; Després, Philippe
2018-01-01
Four-dimensional cone beam computed tomography allows for temporally resolved imaging with useful applications in radiotherapy, but raises particular challenges in terms of image quality and computation time. The purpose of this work is to develop a fast and accurate 4D algorithm by adapting a GPU-accelerated ordered subsets convex algorithm (OSC), combined with the total variation minimization regularization technique (TV). Different initialization schemes were studied to adapt the OSC-TV algorithm to 4D reconstruction: each respiratory phase was initialized either with a 3D reconstruction or a blank image. Reconstruction algorithms were tested on a dynamic numerical phantom and on a clinical dataset. 4D iterations were implemented for a cluster of 8 GPUs. All developed methods allowed for an adequate visualization of the respiratory movement and compared favorably to the McKinnon-Bates and adaptive steepest descent projection onto convex sets algorithms, while the 4D reconstructions initialized from a prior 3D reconstruction led to better overall image quality. The most suitable adaptation of OSC-TV to 4D CBCT was found to be a combination of a prior FDK reconstruction and a 4D OSC-TV reconstruction with a reconstruction time of 4.5 minutes. This relatively short reconstruction time could facilitate a clinical use.
A Fourier-series-based kernel-independent fast multipole method
International Nuclear Information System (INIS)
Zhang Bo; Huang Jingfang; Pitsianis, Nikos P.; Sun Xiaobai
2011-01-01
We present in this paper a new kernel-independent fast multipole method (FMM), named as FKI-FMM, for pairwise particle interactions with translation-invariant kernel functions. FKI-FMM creates, using numerical techniques, sufficiently accurate and compressive representations of a given kernel function over multi-scale interaction regions in the form of a truncated Fourier series. It provides also economic operators for the multipole-to-multipole, multipole-to-local, and local-to-local translations that are typical and essential in the FMM algorithms. The multipole-to-local translation operator, in particular, is readily diagonal and does not dominate in arithmetic operations. FKI-FMM provides an alternative and competitive option, among other kernel-independent FMM algorithms, for an efficient application of the FMM, especially for applications where the kernel function consists of multi-physics and multi-scale components as those arising in recent studies of biological systems. We present the complexity analysis and demonstrate with experimental results the FKI-FMM performance in accuracy and efficiency.
LBM-EP: Lattice-Boltzmann method for fast cardiac electrophysiology simulation from 3D images.
Rapaka, S; Mansi, T; Georgescu, B; Pop, M; Wright, G A; Kamen, A; Comaniciu, Dorin
2012-01-01
Current treatments of heart rhythm troubles require careful planning and guidance for optimal outcomes. Computational models of cardiac electrophysiology are being proposed for therapy planning but current approaches are either too simplified or too computationally intensive for patient-specific simulations in clinical practice. This paper presents a novel approach, LBM-EP, to solve any type of mono-domain cardiac electrophysiology models at near real-time that is especially tailored for patient-specific simulations. The domain is discretized on a Cartesian grid with a level-set representation of patient's heart geometry, previously estimated from images automatically. The cell model is calculated node-wise, while the transmembrane potential is diffused using Lattice-Boltzmann method within the domain defined by the level-set. Experiments on synthetic cases, on a data set from CESC'10 and on one patient with myocardium scar showed that LBM-EP provides results comparable to an FEM implementation, while being 10 - 45 times faster. Fast, accurate, scalable and requiring no specific meshing, LBM-EP paves the way to efficient and detailed models of cardiac electrophysiology for therapy planning.
Fast and reliable methods for extracting functional connectivity in large populations
DEFF Research Database (Denmark)
Roudi, Yasser; Tyrcha, Joanna; Hertz, John
2009-01-01
in that time bin, and 1 if it has emitted one spike or more. One then can construct an Ising model, P(s )=Z-1exp{h.s+sJs} for the spike patterns with the same means and pair correlations as the data, using Boltzmann learning, which is in principle exact. The elements Jij , of the matrix J can be considered...... to be functional couplings. However, Boltzmann learning is prohibitively time-consuming for large networks. Here, we compare the results from five fast approximate methods for finding the couplings with those from Boltzmann learning. We used data from a simulated network of spiking neurons operating...... in a balanced state of asynchronous firing with a mean rate of ~10 Hz for excitatory neurons. Employing a bin size of 10 ms, we performed Boltzmann learning to fit Ising models for populations of size N up to 200 excitatory neurons chosen randomly from the 800 in the simulated network. We studied the following...
Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Nickel
American Society for Testing and Materials. Philadelphia
2008-01-01
1.1 This test method covers procedures for measuring reaction rates by the activation reaction 58Ni(n,p)58Co. 1.2 This activation reaction is useful for measuring neutrons with energies above approximately 2.1 MeV and for irradiation times up to about 200 days in the absence of high thermal neutron fluence rates (for longer irradiations, see Practice E 261). 1.3 With suitable techniques fission-neutron fluence rates densities above 107 cm−2·s−1 can be determined. 1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Note—The burnup corrections were com...
Fraisier, V; Clouvel, G; Jasaitis, A; Dimitrov, A; Piolot, T; Salamero, J
2015-09-01
Multiconfocal microscopy gives a good compromise between fast imaging and reasonable resolution. However, the low intensity of live fluorescent emitters is a major limitation to this technique. Aberrations induced by the optical setup, especially the mismatch of the refractive index and the biological sample itself, distort the point spread function and further reduce the amount of detected photons. Altogether, this leads to impaired image quality, preventing accurate analysis of molecular processes in biological samples and imaging deep in the sample. The amount of detected fluorescence can be improved with adaptive optics. Here, we used a compact adaptive optics module (adaptive optics box for sectioning optical microscopy), which was specifically designed for spinning disk confocal microscopy. The module overcomes undesired anomalies by correcting for most of the aberrations in confocal imaging. Existing aberration detection methods require prior illumination, which bleaches the sample. To avoid multiple exposures of the sample, we established an experimental model describing the depth dependence of major aberrations. This model allows us to correct for those aberrations when performing a z-stack, gradually increasing the amplitude of the correction with depth. It does not require illumination of the sample for aberration detection, thus minimizing photobleaching and phototoxicity. With this model, we improved both signal-to-background ratio and image contrast. Here, we present comparative studies on a variety of biological samples. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.
Reduced-rank approximations to the far-field transform in the gridded fast multipole method
Hesford, Andrew J.; Waag, Robert C.
2011-05-01
The fast multipole method (FMM) has been shown to have a reduced computational dependence on the size of finest-level groups of elements when the elements are positioned on a regular grid and FFT convolution is used to represent neighboring interactions. However, transformations between plane-wave expansions used for FMM interactions and pressure distributions used for neighboring interactions remain significant contributors to the cost of FMM computations when finest-level groups are large. The transformation operators, which are forward and inverse Fourier transforms with the wave space confined to the unit sphere, are smooth and well approximated using reduced-rank decompositions that further reduce the computational dependence of the FMM on finest-level group size. The adaptive cross approximation (ACA) is selected to represent the forward and adjoint far-field transformation operators required by the FMM. However, the actual error of the ACA is found to be greater than that predicted using traditional estimates, and the ACA generally performs worse than the approximation resulting from a truncated singular-value decomposition (SVD). To overcome these issues while avoiding the cost of a full-scale SVD, the ACA is employed with more stringent accuracy demands and recompressed using a reduced, truncated SVD. The results show a greatly reduced approximation error that performs comparably to the full-scale truncated SVD without degrading the asymptotic computational efficiency associated with ACA matrix assembly.
Fast and low-cost method for VBES bathymetry generation in coastal areas
Sánchez-Carnero, N.; Aceña, S.; Rodríguez-Pérez, D.; Couñago, E.; Fraile, P.; Freire, J.
2012-12-01
Sea floor topography is key information in coastal area management. Nowadays, LiDAR and multibeam technologies provide accurate bathymetries in those areas; however these methodologies are yet too expensive for small customers (fishermen associations, small research groups) willing to keep a periodic surveillance of environmental resources. In this paper, we analyse a simple methodology for vertical beam echosounder (VBES) bathymetric data acquisition and postprocessing, using low-cost means and free customizable tools such as ECOSONS and gvSIG (that is compared with industry standard ArcGIS). Echosounder data was filtered, resampled and, interpolated (using kriging or radial basis functions). Moreover, the presented methodology includes two data correction processes: Monte Carlo simulation, used to reduce GPS errors, and manually applied bathymetric line transformations, both improving the obtained results. As an example, we present the bathymetry of the Ría de Cedeira (Galicia, NW Spain), a good testbed area for coastal bathymetry methodologies given its extension and rich topography. The statistical analysis, performed by direct ground-truthing, rendered an upper bound of 1.7 m error, at 95% confidence level, and 0.7 m r.m.s. (cross-validation provided 30 cm and 25 cm, respectively). The methodology presented is fast and easy to implement, accurate outside transects (accuracy can be estimated), and can be used as a low-cost periodical monitoring method.
Methods of preventing fast breeder reactor shield plug from adhesion of sodium
International Nuclear Information System (INIS)
Hashiguchi, Koh; Hara, Johji; Nei, Hiromichi; Daiku, Motoichi; Wagatsuma, Kenji
1980-01-01
The shield plug, which is located at the upper part of a reactor vessel of a sodium-cooled fast breeder reactor, is composed of a rotating and a stationary plug. Fuel exchange is performed easily by the rotation of the rotating plug. The vapor or mist of sodium evaporated from liquid sodium deposits on the gap surfaces of the rotating and stationary plugs and is solidified or changed into a solid reactant. If such condition continues for a long period, harmful effects are exerted on the fuel exchange operation. In order to develop methods of preventing the sodium deposition, investigation was made on the phenomenon of sodium deposition. By the use of the testing equipment simulating the shield plug, deposition tests and specimen measurements were made for different gap width test section size and condition. On the basis of the effects of these parameters clarified by experiments, the effectiveness of three kinds of mechanism for preventing sodium deposition were investigated experimentally. In addition, by using a thermo-siphon analogical model, analysis was performed to deduce experimental equations for sodium deposition. (author)
Application of fast fourier transform method to evaluate the accuracy of sbloca data base
International Nuclear Information System (INIS)
D'Auria, F.; Galassi, G.M.; Leonardi, M.; Galetti, M.R.
1997-01-01
The purpose of this paper is to perform the quantitative accuracy evaluation of a small break LOCA data base and then evaluate the accuracy of RELAP5/MOD2 code i.e. of the ensemble constituted by the code itself, the user, the nodalization and the selected code options, in predicting this kind of transient. In order to achieve this objective, qualitative accuracy evaluation results from several tests performed in 4 facilities (LOBI, SPES, BETHSY and LSTF) are used. The quantitative evaluation is achieved adopting a method developed at University of Pisa, which has capabilities in quantifying the errors in code predictions with respect to the measured experimental signal, using the Fast Fourier Transform; this allows an integral representation of code discrepancies in the frequency domain. The RELAP5/MOD2 code has been extensively used at the University of Pisa and the nodalizations of the 4 facilities have been qualified through the application to several experiments performed in the same facilities. (author)
A study of group constant generation method in fast reactor analysis
International Nuclear Information System (INIS)
Takano, Hideki
1983-05-01
The methods of generating group constants have been studied to predict accurately the nuclear characteristics of fast reactors. In resonance energy region, the accuracy of the group constants was investigated, which were calculated by the approximate weighting spectrum used for a conventional standards group constant set such as ABBN. It was shown that the basic assumption of constant collision density for group constant calculation was not always satisfactory. Moreover, a multilevel formula was derived without losing the useful characteristics of the Breit-Wigner single level formula. Using this formula, the interference effect between resonances was examined. In addition, the mutual interference between different resonant nuclides was calculated. The cause of a systematic dependence of effective multiplication factors on U-238 concentration ratio was studied, and the cross section adjustment was performed. In the unresolved resonance region, the average resonance parameters were searched. As a result, the JFS-2 set was generated, and several studies were performed to advance the concept of the group constant set JFS-2. (Kako, I.)
Newton, Richard J G; Stuart, Grant M; Willdridge, Daniel J; Thomas, Mark
2017-08-01
We applied quality improvement (QI) methodology to identify the different aspects of why children fasted for prolonged periods in our institution. Our aim was for 75% of all children to be fasted for clear fluid for less than 4 hours. Prolonged fasting in children can increase thirst and irritability and have adverse effects on haemodynamic stability on induction. By reducing this, children may be less irritable, more comfortable and more physiologically stable, improving the preoperative experience for both children and carers. We conducted a QI project from January 2014 until August 2016 at a large tertiary pediatric teaching hospital. Baseline data and the magnitude of the problem were obtained from pilot studies. This allowed us to build a key driver diagram, a process map and conduct a failure mode and effects analysis. Using a framework of Plan-Do-Study-Act cycles our key interventions primarily focused on reducing confusion over procedure start times, giving parents accurate information, empowering staff and reducing variation by allowing children to drink on arrival (up to one hour) before surgery. Prior to this project, using the 6,4,2 fasting rule for solids, breast milk, and clear fluids, respectively, 19% of children were fasted for fluid for less than 4 hours, mean fluid fasting time was 6.3 hours (SD 4.48). At the conclusion 72% of patients received a drink within 4 hours, mean fluid fasting reduced to 3.1 hours (SD 2.33). The secondary measures of aspiration (4.14:10 000) and cancellations have not increased since starting this project. By using established QI methodology we reduced the mean fluid fasting time for day admissions at our hospital to 3.1 hours and increased the proportion of children fasting for less than 4 hours from 19% to 72%. © 2017 John Wiley & Sons Ltd.
Wang Hao; Gao Wen; Huang Qingming; Zhao Feng
2010-01-01
Similarity measures based on correlation have been used extensively for matching tasks. However, traditional correlation-based image matching methods are sensitive to rotation and scale changes. This paper presents a fast correlation-based method for matching two images with large rotation and significant scale changes. Multiscale oriented corner correlation (MOCC) is used to evaluate the degree of similarity between the feature points. The method is rotation invariant and capable of matchin...
The MusIC method: a fast and quasi-optimal solution to the muscle forces estimation problem
Muller , Antoine; Pontonnier , Charles; Dumont , Georges
2018-01-01
International audience; The present paper aims at presenting a fast and quasi-optimal method of muscle forces estimation: the MusIC method. It consists in interpolating a first estimation in a database generated offline thanks to a classical optimization problem, and then correcting it to respect the motion dynamics. Three different cost functions – two polynomial criteria and a min/max criterion – were tested on a planar musculoskeletal model. The MusIC method provides a computation frequenc...
RADAR: A novel fast-screening method for reading difficulties with special focus on dyslexia
Smyrnakis, Ioannis; Andreadakis, Vassilios; Selimis, Vassilios; Kalaitzakis, Michail; Bachourou, Theodora; Kaloutsakis, Georgios; Kymionis, George D.; Smirnakis, Stelios; Aslanides, Ioannis M.
2017-01-01
Dyslexia is a developmental learning disorder of single word reading accuracy and/or fluency, with compelling research directed towards understanding the contributions of the visual system. While dyslexia is not an oculomotor disease, readers with dyslexia have shown different eye movements than typically developing students during text reading. Readers with dyslexia exhibit longer and more frequent fixations, shorter saccade lengths, more backward refixations than typical readers. Furthermore, readers with dyslexia are known to have difficulty in reading long words, lower skipping rate of short words, and high gaze duration on many words. It is an open question whether it is possible to harness these distinctive oculomotor scanning patterns observed during reading in order to develop a screening tool that can reliably identify struggling readers, who may be candidates for dyslexia. Here, we introduce a novel, fast, objective, non-invasive method, named Rapid Assessment of Difficulties and Abnormalities in Reading (RADAR) that screens for features associated with the aberrant visual scanning of reading text seen in dyslexia. Eye tracking parameter measurements that are stable under retest and have high discriminative power, as indicated by their ROC (receiver operating characteristic) curves, were obtained during silent text reading. These parameters were combined to derive a total reading score (TRS) that can reliably separate readers with dyslexia from typical readers. We tested TRS in a group of school-age children ranging from 8.5 to 12.5 years of age. TRS achieved 94.2% correct classification of children tested. Specifically, 35 out of 37 control (specificity 94.6%) and 30 out of 32 readers with dyslexia (sensitivity 93.8%) were classified correctly using RADAR, under a circular validation condition (see section Results/Total Reading Score) where the individual evaluated was not included in the test construction group. In conclusion, RADAR is a novel
RADAR: A novel fast-screening method for reading difficulties with special focus on dyslexia.
Smyrnakis, Ioannis; Andreadakis, Vassilios; Selimis, Vassilios; Kalaitzakis, Michail; Bachourou, Theodora; Kaloutsakis, Georgios; Kymionis, George D; Smirnakis, Stelios; Aslanides, Ioannis M
2017-01-01
Dyslexia is a developmental learning disorder of single word reading accuracy and/or fluency, with compelling research directed towards understanding the contributions of the visual system. While dyslexia is not an oculomotor disease, readers with dyslexia have shown different eye movements than typically developing students during text reading. Readers with dyslexia exhibit longer and more frequent fixations, shorter saccade lengths, more backward refixations than typical readers. Furthermore, readers with dyslexia are known to have difficulty in reading long words, lower skipping rate of short words, and high gaze duration on many words. It is an open question whether it is possible to harness these distinctive oculomotor scanning patterns observed during reading in order to develop a screening tool that can reliably identify struggling readers, who may be candidates for dyslexia. Here, we introduce a novel, fast, objective, non-invasive method, named Rapid Assessment of Difficulties and Abnormalities in Reading (RADAR) that screens for features associated with the aberrant visual scanning of reading text seen in dyslexia. Eye tracking parameter measurements that are stable under retest and have high discriminative power, as indicated by their ROC (receiver operating characteristic) curves, were obtained during silent text reading. These parameters were combined to derive a total reading score (TRS) that can reliably separate readers with dyslexia from typical readers. We tested TRS in a group of school-age children ranging from 8.5 to 12.5 years of age. TRS achieved 94.2% correct classification of children tested. Specifically, 35 out of 37 control (specificity 94.6%) and 30 out of 32 readers with dyslexia (sensitivity 93.8%) were classified correctly using RADAR, under a circular validation condition (see section Results/Total Reading Score) where the individual evaluated was not included in the test construction group. In conclusion, RADAR is a novel
RADAR: A novel fast-screening method for reading difficulties with special focus on dyslexia.
Directory of Open Access Journals (Sweden)
Ioannis Smyrnakis
Full Text Available Dyslexia is a developmental learning disorder of single word reading accuracy and/or fluency, with compelling research directed towards understanding the contributions of the visual system. While dyslexia is not an oculomotor disease, readers with dyslexia have shown different eye movements than typically developing students during text reading. Readers with dyslexia exhibit longer and more frequent fixations, shorter saccade lengths, more backward refixations than typical readers. Furthermore, readers with dyslexia are known to have difficulty in reading long words, lower skipping rate of short words, and high gaze duration on many words. It is an open question whether it is possible to harness these distinctive oculomotor scanning patterns observed during reading in order to develop a screening tool that can reliably identify struggling readers, who may be candidates for dyslexia. Here, we introduce a novel, fast, objective, non-invasive method, named Rapid Assessment of Difficulties and Abnormalities in Reading (RADAR that screens for features associated with the aberrant visual scanning of reading text seen in dyslexia. Eye tracking parameter measurements that are stable under retest and have high discriminative power, as indicated by their ROC (receiver operating characteristic curves, were obtained during silent text reading. These parameters were combined to derive a total reading score (TRS that can reliably separate readers with dyslexia from typical readers. We tested TRS in a group of school-age children ranging from 8.5 to 12.5 years of age. TRS achieved 94.2% correct classification of children tested. Specifically, 35 out of 37 control (specificity 94.6% and 30 out of 32 readers with dyslexia (sensitivity 93.8% were classified correctly using RADAR, under a circular validation condition (see section Results/Total Reading Score where the individual evaluated was not included in the test construction group. In conclusion, RADAR is a
Cvetkovikj, I; Stefkov, G; Acevska, J; Stanoeva, J Petreska; Karapandzova, M; Stefova, M; Dimitrovska, A; Kulevanova, S
2013-03-22
Although the knowledge and use of several Salvia species (Salvia officinalis, Salvia fruticosa, and Salvia pomifera) can be dated back to Greek Era and have a long history of culinary and effective medicinal use, still there is a remarkable interest concerning their chemistry and especially the polyphenolic composition. Despite the demand in the food and pharmaceutical industry for methods for fast quality assessment of the herbs and spices, even now there are no official requirements for the minimum content of polyphenols in sage covered by current regulations neither the European Pharmacopoeia monographs nor the ISO 11165 standard. In this work a rapid analytical method for extraction, characterization and quantification of the major polyphenolic constituents in Sage was developed. Various extractions (infusion - IE; ultrasound-assisted extraction - USE and microwave-assisted extraction - MWE) were performed and evaluated for their effectiveness. Along with the optimization of the mass-detector and chromatographic parameters, the applicability of three different reverse C18 stationary phases (extra-density bonded, core-shell technology and monolith column) for polyphenolics characterization was evaluated. A comprehensive overview of the very variable polyphenolic composition of 118 different plant samples of 68 populations of wild growing culinary Salvia species (S. officinalis: 101; S. fruticosa: 15; S. pomifera: 2) collected from South East Europe (SEE) was performed using HPLC-DAD-ESI-MS(n) and more than 50 different compounds were identified and quantified. With this work the knowledge about polyphenols of culinary Sage was expanded thus the possibility for gaining an insight into the chemodiversity of culinary Salvia species in South East Europe was unlocked. Copyright © 2013 Elsevier B.V. All rights reserved.
Accurate and fast methods to estimate the population mutation rate from error prone sequences
Directory of Open Access Journals (Sweden)
Miyamoto Michael M
2009-08-01
Full Text Available Abstract Background The population mutation rate (θ remains one of the most fundamental parameters in genetics, ecology, and evolutionary biology. However, its accurate estimation can be seriously compromised when working with error prone data such as expressed sequence tags, low coverage draft sequences, and other such unfinished products. This study is premised on the simple idea that a random sequence error due to a chance accident during data collection or recording will be distributed within a population dataset as a singleton (i.e., as a polymorphic site where one sampled sequence exhibits a unique base relative to the common nucleotide of the others. Thus, one can avoid these random errors by ignoring the singletons within a dataset. Results This strategy is implemented under an infinite sites model that focuses on only the internal branches of the sample genealogy where a shared polymorphism can arise (i.e., a variable site where each alternative base is represented by at least two sequences. This approach is first used to derive independently the same new Watterson and Tajima estimators of θ, as recently reported by Achaz 1 for error prone sequences. It is then used to modify the recent, full, maximum-likelihood model of Knudsen and Miyamoto 2, which incorporates various factors for experimental error and design with those for coalescence and mutation. These new methods are all accurate and fast according to evolutionary simulations and analyses of a real complex population dataset for the California seahare. Conclusion In light of these results, we recommend the use of these three new methods for the determination of θ from error prone sequences. In particular, we advocate the new maximum likelihood model as a starting point for the further development of more complex coalescent/mutation models that also account for experimental error and design.
Energy Technology Data Exchange (ETDEWEB)
Ferrell, Jack R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ware, Anne E [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2018-02-25
Two catalytic fast pyrolysis (CFP) oils (bottom/heavy fraction) were analyzed in various solvents that are used in common analytical methods (nuclear magnetic resonance - NMR, gas chromatography - GC, gel permeation chromatography - GPC, thermogravimetric analysis - TGA) for oil characterization and speciation. A more accurate analysis of the CFP oils can be obtained by identification and exploitation of solvent miscibility characteristics. Acetone and tetrahydrofuran can be used to completely solubilize CFP oils for analysis by GC and tetrahydrofuran can be used for traditional organic GPC analysis of the oils. DMSO-d6 can be used to solubilize CFP oils for analysis by 13C NMR. The fractionation of oils into solvents that did not completely solubilize the whole oils showed that miscibility can be related to the oil properties. This allows for solvent selection based on physico-chemical properties of the oils. However, based on semi-quantitative comparisons of the GC chromatograms, the organic solvent fractionation schemes did not speciate the oils based on specific analyte type. On the other hand, chlorinated solvents did fractionate the oils based on analyte size to a certain degree. Unfortunately, like raw pyrolysis oil, the matrix of the CFP oils is complicated and is not amenable to simple liquid-liquid extraction (LLE) or solvent fractionation to separate the oils based on the chemical and/or physical properties of individual components. For reliable analyses, for each analytical method used, it is critical that the bio-oil sample is both completely soluble and also not likely to react with the chosen solvent. The adoption of the standardized solvent selection protocols presented here will allow for greater reproducibility of analysis across different users and facilities.
Ontwikkeling van een FAST-LC methode voor een aantal nitrofuranen in vlees en melk
Anonymous,
1985-01-01
Door toepassing van het zogenaamde "FAST-LC systeem" kunnen monsters zonder veel manuele handelingen automatisch worden geanalyseerd op nitrofuranen, medicinale stoffen met een breed werkingsspectrum, toegepast tegen infectieziekten bij runderen, varkens en pluimvee. In de Verenigde Staten mogen
Wen, Weijia; Wu, Jinbo; Kodzius, Rimantas
2011-01-01
A polymerase chain reaction (PCR) device for fast amplification and detection of DNA includes an interchangeable PCR chamber, a temperature control component, and an optical detection system. The DNA amplification is performed on an interchangeable
Energy Technology Data Exchange (ETDEWEB)
Cambou, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1961-02-15
This research aimed at improving fast-neutron electronic detectors based on n-p elastic scattering. The first part concerns proportional counters; careful constructional methods have made it possible to plot mono-energetic neutron spectra in the range 700 keV - 3 MeV with a resolution of 7 per cent. The second part concerns scintillation counters: an organic scintillator and an inorganic scintillator covered with a thin layer of a scattering agent. An exact study of the types of scintillation has made it possible to develop efficient discriminator circuits. Different neutron spectra plotted in the presence of a strong gamma background are presented. The last part deals with the development of form discrimination methods for the study, in the actual beam, of the elastic scattering of 14.58 MeV electrons. With hydrogen, the distribution f ({phi}) of the recoil protons is f({phi}) = 1 + 0.034 cos {phi} + 0.042 cos{sup 2} {phi}. With tritium the scattering is strongly anisotropic; the curve representing the variation of the differential cross-section for the elastic scattering in the centre of mass system is obtained with a target containing 1 cm{sup 3} of tritium. (author) [French] Le travail a porte sur l'amelioration des detecteurs electroniques de neutrons rapides bases sur la diffusion elastique n-p. La premiere partie est relative aux compteurs proportionnels; des methodes soignees de fabrication ont permis des traces de spectres de neutrons monoenergetiques dans le domaine 700 keV - 3 MeV avec une resolution de 7 pour cent. La deuxieme partie est relative au compteur a scintillations; scintillateur organique et scintillateur mineral recouvert d'un diffuseur mince. Une etude precise des formes de scintillations a permis la mise au point de circuits discriminateurs efficaces. Differents spectres de neutrons traces en presence d'un fond gamma intense sont presentes. La derniere partie est relative a la mise en oeuvre des methodes de discrimination de forme pour l
Energy Technology Data Exchange (ETDEWEB)
NONE
2013-08-15
The purposes of this study is to establish the safety evaluation methods needed in the operation stage of fast breeder reactor (FBR). Related the above purpose of this study, some investigation studies for the technical standard applied to Monju were achieved in JFY 2012. (author)
Schellen, A.; Ooms, B.; Lagemaat, D. van de; Vreeken, R.; Dongen, W.D. van
2003-01-01
A generic method was developed for the fast determination of a wide range of drugs in serum or plasma. The methodology comprises generic solid-phase extraction, on-line coupled to gradient HPLC with tandem mass spectrometric detection (SPE-LC-MS/MS). The individual components of the SPE-LC-MS/MS
DEFF Research Database (Denmark)
Sakamuri, Jayachandra N.; Hansen, Anca Daniela; Altin, Müfit
2017-01-01
Increased penetration of offshore wind power plants (OWPPs) demands frequency control services from them. Overloading the wind turbine, for few seconds after the under frequency event, to utilize its kinetic energy seems promising option for fast primary frequency control. Two methods...
International Nuclear Information System (INIS)
Kawai, Y.; Alton, G.D.; Bilheux, J.-C.
2005-01-01
An inexpensive, fast, and close to universal infiltration coating technique has been developed for fabricating fast diffusion-release ISOL targets. Targets are fabricated by deposition of finely divided (∼1μm) compound materials in a paint-slurry onto highly permeable, complex structure reticulated-vitreous-carbon-foam (RVCF) matrices, followed by thermal heat treatment. In this article, we describe the coating method and present information on the physical integrity, uniformity of deposition, and matrix adherence of SiC, HfC and UC 2 targets, destined for on-line use as targets at the Holifield Radioactive Ion Beam Facility (HRIBF)
International Nuclear Information System (INIS)
Bennett, R.A.; Harris, R.A.; Daughtry, J.W.
1981-09-01
Final confirmation of much of the engineering mockup work has been achieved in FTR zero-power experiments in February, 1980, and in power demonstration performed in December, 1980, and March, 1981. Final in-core low-power and high-power irradiation of spatially distributed radioactivants will be completed late in 1981. This paper describes physics experiments and present summaries of the extensive results accumulated to date. 53 figures
a Fast and Flexible Method for Meta-Map Building for Icp Based Slam
Kurian, A.; Morin, K. W.
2016-06-01
Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM) is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP) algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.
A FAST AND FLEXIBLE METHOD FOR META-MAP BUILDING FOR ICP BASED SLAM
Directory of Open Access Journals (Sweden)
A. Kurian
2016-06-01
Full Text Available Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.
AbdulJabbar, Mustafa Abdulmajeed
2017-07-31
Manycore optimizations are essential for achieving performance worthy of anticipated exascale systems. Utilization of manycore chips is inevitable to attain the desired floating point performance of these energy-austere systems. In this work, we revisit ExaFMM, the open source Fast Multiple Method (FMM) library, in light of highly tuned shared-memory parallelization and detailed performance analysis on the new highly parallel Intel manycore architecture, Knights Landing (KNL). We assess scalability and performance gain using task-based parallelism of the FMM tree traversal. We also provide an in-depth analysis of the most computationally intensive part of the traversal kernel (i.e., the particle-to-particle (P2P) kernel), by comparing its performance across KNL and Broadwell architectures. We quantify different configurations that exploit the on-chip 512-bit vector units within different task-based threading paradigms. MPI communication-reducing and NUMA-aware approaches for the FMM’s global tree data exchange are examined with different cluster modes of KNL. By applying several algorithm- and architecture-aware optimizations for FMM, we show that the N-Body kernel on 256 threads of KNL achieves on average 2.8× speedup compared to the non-vectorized version, whereas on 56 threads of Broadwell, it achieves on average 2.9× speedup. In addition, the tree traversal kernel on KNL scales monotonically up to 256 threads with task-based programming models. The MPI-based communication-reducing algorithms show expected improvements of the data locality across the KNL on-chip network.
Zhou, Jian; Li, Er Qiang; Lubineau, Gilles; Thoroddsen, Sigurdur T; Mulle, Matthieu
2016-01-01
A method comprising: providing at least one first composition comprising at least one conjugated polymer and at least one solvent, wet spinning the at least one first composition to form at least one first fiber material, hot-drawing the at least one fiber to form at least one second fiber material. In lead embodiments, high-performance poly(3,4-ethylenedioxy- thiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet- spinning followed by hot-drawing. In these lead embodiments, due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), a record electrical conductivity of 2804 S · cm-1 was achieved. This is believed to be a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S · cm-1) and a twofold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S · cm-1). Moreover, these lead, highly conductive fibers experience a semiconductor-metal transition at 313 K. They also have superior mechanical properties with a Young's modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers can make them available for conductive smart electronics. A dramatic improvement in electrical conductivity is needed to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators.
Prest, Emmanuelle I E C; Hammes, Frederik A.; Kö tzsch, Stefan; van Loosdrecht, Mark C.M.; Vrouwenvelder, Johannes S.
2013-01-01
Flow cytometry (FCM) is a rapid, cultivation-independent tool to assess and evaluate bacteriological quality and biological stability of water. Here we demonstrate that a stringent, reproducible staining protocol combined with fixed FCM operational and gating settings is essential for reliable quantification of bacteria and detection of changes in aquatic bacterial communities. Triplicate measurements of diverse water samples with this protocol typically showed relative standard deviation values and 95% confidence interval values below 2.5% on all the main FCM parameters. We propose a straightforward and instrument-independent method for the characterization of water samples based on the combination of bacterial cell concentration and fluorescence distribution. Analysis of the fluorescence distribution (or so-called fluorescence fingerprint) was accomplished firstly through a direct comparison of the raw FCM data and subsequently simplified by quantifying the percentage of large and brightly fluorescent high nucleic acid (HNA) content bacteria in each sample. Our approach enables fast differentiation of dissimilar bacterial communities (less than 15min from sampling to final result), and allows accurate detection of even small changes in aquatic environments (detection above 3% change). Demonstrative studies on (a) indigenous bacterial growth in water, (b) contamination of drinking water with wastewater, (c) household drinking water stagnation and (d) mixing of two drinking water types, univocally showed that this FCM approach enables detection and quantification of relevant bacterial water quality changes with high sensitivity. This approach has the potential to be used as a new tool for application in the drinking water field, e.g. for rapid screening of the microbial water quality and stability during water treatment and distribution in networks and premise plumbing. © 2013 Elsevier Ltd.
AbdulJabbar, Mustafa Abdulmajeed; Al Farhan, Mohammed; Yokota, Rio; Keyes, David E.
2017-01-01
Manycore optimizations are essential for achieving performance worthy of anticipated exascale systems. Utilization of manycore chips is inevitable to attain the desired floating point performance of these energy-austere systems. In this work, we revisit ExaFMM, the open source Fast Multiple Method (FMM) library, in light of highly tuned shared-memory parallelization and detailed performance analysis on the new highly parallel Intel manycore architecture, Knights Landing (KNL). We assess scalability and performance gain using task-based parallelism of the FMM tree traversal. We also provide an in-depth analysis of the most computationally intensive part of the traversal kernel (i.e., the particle-to-particle (P2P) kernel), by comparing its performance across KNL and Broadwell architectures. We quantify different configurations that exploit the on-chip 512-bit vector units within different task-based threading paradigms. MPI communication-reducing and NUMA-aware approaches for the FMM’s global tree data exchange are examined with different cluster modes of KNL. By applying several algorithm- and architecture-aware optimizations for FMM, we show that the N-Body kernel on 256 threads of KNL achieves on average 2.8× speedup compared to the non-vectorized version, whereas on 56 threads of Broadwell, it achieves on average 2.9× speedup. In addition, the tree traversal kernel on KNL scales monotonically up to 256 threads with task-based programming models. The MPI-based communication-reducing algorithms show expected improvements of the data locality across the KNL on-chip network.
Technical Note: A fast online adaptive replanning method for VMAT using flattening filter free beams
Energy Technology Data Exchange (ETDEWEB)
Ates, Ozgur; Ahunbay, Ergun E.; Li, X. Allen, E-mail: ali@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226 (United States); Moreau, Michel [Elekta, Inc., Maryland Heights, Missouri 63043 (United States)
2016-06-15
Purpose: To develop a fast replanning algorithm based on segment aperture morphing (SAM) for online replanning of volumetric modulated arc therapy (VMAT) with flattening filter free (FFF) beams. Methods: A software tool was developed to interface with a VMAT research planning system, which enables the input and output of beam and machine parameters of VMAT plans. The SAM algorithm was used to modify multileaf collimator positions for each segment aperture based on the changes of the target from the planning (CT/MR) to daily image [CT/CBCT/magnetic resonance imaging (MRI)]. The leaf travel distance was controlled for large shifts to prevent the increase of VMAT delivery time. The SAM algorithm was tested for 11 patient cases including prostate, pancreatic, and lung cancers. For each daily image set, three types of VMAT plans, image-guided radiation therapy (IGRT) repositioning, SAM adaptive, and full-scope reoptimization plans, were generated and compared. Results: The SAM adaptive plans were found to have improved the plan quality in target and/or critical organs when compared to the IGRT repositioning plans and were comparable to the reoptimization plans based on the data of planning target volume (PTV)-V100 (volume covered by 100% of prescription dose). For the cases studied, the average PTV-V100 was 98.85% ± 1.13%, 97.61% ± 1.45%, and 92.84% ± 1.61% with FFF beams for the reoptimization, SAM adaptive, and repositioning plans, respectively. The execution of the SAM algorithm takes less than 10 s using 16-CPU (2.6 GHz dual core) hardware. Conclusions: The SAM algorithm can generate adaptive VMAT plans using FFF beams with comparable plan qualities as those from the full-scope reoptimization plans based on daily CT/CBCT/MRI and can be used for online replanning to address interfractional variations.
Ibeid, Huda
2016-03-04
Exascale systems are predicted to have approximately 1 billion cores, assuming gigahertz cores. Limitations on affordable network topologies for distributed memory systems of such massive scale bring new challenges to the currently dominant parallel programing model. Currently, there are many efforts to evaluate the hardware and software bottlenecks of exascale designs. It is therefore of interest to model application performance and to understand what changes need to be made to ensure extrapolated scalability. The fast multipole method (FMM) was originally developed for accelerating N-body problems in astrophysics and molecular dynamics but has recently been extended to a wider range of problems. Its high arithmetic intensity combined with its linear complexity and asynchronous communication patterns make it a promising algorithm for exascale systems. In this paper, we discuss the challenges for FMM on current parallel computers and future exascale architectures, with a focus on internode communication. We focus on the communication part only; the efficiency of the computational kernels are beyond the scope of the present study. We develop a performance model that considers the communication patterns of the FMM and observe a good match between our model and the actual communication time on four high-performance computing (HPC) systems, when latency, bandwidth, network topology, and multicore penalties are all taken into account. To our knowledge, this is the first formal characterization of internode communication in FMM that validates the model against actual measurements of communication time. The ultimate communication model is predictive in an absolute sense; however, on complex systems, this objective is often out of reach or of a difficulty out of proportion to its benefit when there exists a simpler model that is inexpensive and sufficient to guide coding decisions leading to improved scaling. The current model provides such guidance.
Prest, Emmanuelle I E C
2013-12-01
Flow cytometry (FCM) is a rapid, cultivation-independent tool to assess and evaluate bacteriological quality and biological stability of water. Here we demonstrate that a stringent, reproducible staining protocol combined with fixed FCM operational and gating settings is essential for reliable quantification of bacteria and detection of changes in aquatic bacterial communities. Triplicate measurements of diverse water samples with this protocol typically showed relative standard deviation values and 95% confidence interval values below 2.5% on all the main FCM parameters. We propose a straightforward and instrument-independent method for the characterization of water samples based on the combination of bacterial cell concentration and fluorescence distribution. Analysis of the fluorescence distribution (or so-called fluorescence fingerprint) was accomplished firstly through a direct comparison of the raw FCM data and subsequently simplified by quantifying the percentage of large and brightly fluorescent high nucleic acid (HNA) content bacteria in each sample. Our approach enables fast differentiation of dissimilar bacterial communities (less than 15min from sampling to final result), and allows accurate detection of even small changes in aquatic environments (detection above 3% change). Demonstrative studies on (a) indigenous bacterial growth in water, (b) contamination of drinking water with wastewater, (c) household drinking water stagnation and (d) mixing of two drinking water types, univocally showed that this FCM approach enables detection and quantification of relevant bacterial water quality changes with high sensitivity. This approach has the potential to be used as a new tool for application in the drinking water field, e.g. for rapid screening of the microbial water quality and stability during water treatment and distribution in networks and premise plumbing. © 2013 Elsevier Ltd.
Zhou, Jian
2016-06-09
A method comprising: providing at least one first composition comprising at least one conjugated polymer and at least one solvent, wet spinning the at least one first composition to form at least one first fiber material, hot-drawing the at least one fiber to form at least one second fiber material. In lead embodiments, high-performance poly(3,4-ethylenedioxy- thiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet- spinning followed by hot-drawing. In these lead embodiments, due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), a record electrical conductivity of 2804 S · cm-1 was achieved. This is believed to be a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S · cm-1) and a twofold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S · cm-1). Moreover, these lead, highly conductive fibers experience a semiconductor-metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers can make them available for conductive smart electronics. A dramatic improvement in electrical conductivity is needed to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators.
Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D
2013-01-01
The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...
Markantonis, V.; Bithas, K.
2009-04-01
In March 2006 Greece was struck by a severe flooding, which caused significant damages in the Prefecture of Evros, on the Eastern border of Greece. 250 million m² of farmland was flooded causing severe damages to agriculture, transport and water supply networks. Total direct damages are estimated at € 372 million. The negative effect on economic activity caused by the floods, considered the worst over the last 50 years, took place in an area that had already been severely affected by floods in 2005. Apart from the direct damages critical were also the indirect impacts on the environmental and the social level. The need for economic analysis concerning the design and implementation of efficient flood management policies is well emphasized in the natural hazards' policies. Within this framework, the present paper is analyzing the application of stated preferences valuation techniques for the assessment of the damages caused in the Prefecture of Evros by the severe floods of March 2006. The objective of this paper is to define the role of economic valuation techniques in assisting the design of efficient and sustainable policies for flood management. More specific, the Contingent Valuation (CV) method is applied in order to valuate the impacts of the March 2006 floods, including the environmental impacts as far as concerns the soil, the biodiversity and the aesthetic environment of the flooded areas. The paper begins with a discussion of the theoretical economic framework, and particularly, the contingent valuation method framework that can be used to evaluate flood impacts. Understanding public preferences for complex environmental policy changes, such as flood impacts, is a preeminent challenge for environmental economists and other social scientists. Information issues are central to the design and application of the survey-based contingent valuation (CV) method for valuing environmental goods. While content is under the control of the analyst, how this
March 2010 Final for Publicat...
African Journals Online (AJOL)
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March 2010 Vol. 13 (1):32-36. EPISTAXIS IN SAGAMU. *OA Sogebi,**EA Oyewole ,***OA Adebajo. ABSTRACT. Background: Materials and Methods: Results: Conclusion: Key Words ... Anterior rhinoscopy: Examination of the nasal cavities through the .... post-irradiation nasopharyngeal cancer patients with internal carotid ...
International Nuclear Information System (INIS)
Liu Qingwei; Liu Shengkang; Zhang Zhiping; Ding Xiaoping
2006-01-01
The principle, experiment and conclusion on the grease stain measurement using fast neutron are reported. The experiment equipment consist of 241 Am-Be fast neutron source, ZnS detector and BH1224 multichannel spectrometer. Paraffin is used instead of real grease stain. Steel plates are used instead of pipeline. The results of the experiment indicate that there is a good linearship between the logarithm of the reciprocal of the neutron transmissivity and the paraffin thickness. The measuring accuracy of the paraffin thickness is 0.6 mm in this experiment. (authors)
International Nuclear Information System (INIS)
Mizuno, M.; Enokido, Y.; Itaki, T.; Kono, K.; Unno, I.; Yamanouchi, S.
1985-01-01
A new method of burnup measurement using a shielded ion microprobe analyzer (SIMA) has been developed. The method is based on the isotope analysis of uranium, plutonium, and fission products in irradiated mixed oxide fuel by means of secondary ion mass spectrometry (SIMS). Fourteen samples irradiated in the Japanese experimental fast reactor JOYO were examined. The maximum local burnup of JOYO MK-I core fuels was about5.1 at. %. The axial burnup distribution of the fuel pin was in good agreement with that of the sibling pin in the same subassembly, measured by surface ionization mass spectrometry, which requires the chemical separation of fission products and heavy metals. The new method facilitates the rapid and accurate measurement of fast breeder reactor fuel burnup without human radiation exposure during sample preparation and analysis
International Nuclear Information System (INIS)
Matausek, M.
1972-01-01
A new proposed method for solving the space-energy dependent spherical harmonics equations represents a methodological contribution to neutron transport theory. The proposed method was applied for solving the problem of spec-energy transport of fast and resonance neutrons in multi-zone, cylindrical y symmetric infinite reactor cell and is related to previously developed procedure for treating the thermal energy region. The advantages of this method are as follows: a unique algorithm was obtained for detailed determination of spatial and energy distribution of neutrons (from thermal to fast) in the reactor cell; these detailed distributions enable more precise calculations of criticality conditions, obtaining adequate multigroup data and better interpretation of experimental data; computing time is rather short
Ultra-fast scintillation properties of β-Ga2O3 single crystals grown by Floating Zone method
He, Nuotian; Tang, Huili; Liu, Bo; Zhu, Zhichao; Li, Qiu; Guo, Chao; Gu, Mu; Xu, Jun; Liu, Jinliang; Xu, Mengxuan; Chen, Liang; Ouyang, Xiaoping
2018-04-01
In this investigation, β-Ga2O3 single crystals were grown by the Floating Zone method. At room temperature, the X-ray excited emission spectrum includes ultraviolet and blue emission bands. The scintillation light output is comparable to the commercial BGO scintillator. The scintillation decay times are composed of the dominant ultra-fast component of 0.368 ns and a small amount of slightly slow components of 8.2 and 182 ns. Such fast component is superior to most commercial inorganic scintillators. In contrast to most semiconductor crystals prepared by solution method such as ZnO, β-Ga2O3 single crystals can be grown by traditional melt-growth method. Thus we can easily obtain large bulk crystals and mass production.
Young, D. P.; Woo, A. C.; Bussoletti, J. E.; Johnson, F. T.
1986-01-01
A general method is developed combining fast direct methods and boundary integral equation methods to solve Poisson's equation on irregular exterior regions. The method requires O(N log N) operations where N is the number of grid points. Error estimates are given that hold for regions with corners and other boundary irregularities. Computational results are given in the context of computational aerodynamics for a two-dimensional lifting airfoil. Solutions of boundary integral equations for lifting and nonlifting aerodynamic configurations using preconditioned conjugate gradient are examined for varying degrees of thinness.
International Nuclear Information System (INIS)
Kamide, H.; Kimura, N.; Miyakoshi, H.; Nagasawa, K.
2001-01-01
Decay heat removal using natural circulation is one of the important functions for the safety of fast reactors. As a decay heat removal system, direct reactor auxiliary cooling system has been selected in current designs of fast reactors. In this design, dumped heat exchanger provides cold sodium and it covers the reactor core outlet. The cold sodium can penetrate into the gap region between the subassemblies. This gap flow is referred as inter-wrapper flow (IWF). A numerical estimation method for such natural circulation phenomena in a reactor core has been developed, which models each subassembly as a rectangular duct with gap region between the subassemblies and also the upper plenum in a reactor vessel. This numerical simulation method was verified based on experimental data of a sodium test using 7- subassembly core model and also a water test which simulates IWF using the 1/12 sector model of a reactor core. We applied the estimation method to the natural circulation in a 600 MW class fast reactor. The temperature in the core strongly depended on IWF, flow redistribution in the core, and inter-subassembly heat transfer. It is desired for prediction methods on the natural circulation to simulate these phenomena. (author)
Jackson, W. B., Ed.; Marsh, R. E., Ed.
The first symposium on "Test Methods for Vertebrate Pest Management" was held in March, 1976. Much of the thrust was toward explaining and defining the "state of the art." Concerns included rodents and rabbits, predators, scavengers, and large game animals, and a variety of bird species. Environments were as restricted as a…
Hesford, Andrew J.; Waag, Robert C.
2010-10-01
The fast multipole method (FMM) is applied to the solution of large-scale, three-dimensional acoustic scattering problems involving inhomogeneous objects defined on a regular grid. The grid arrangement is especially well suited to applications in which the scattering geometry is not known a priori and is reconstructed on a regular grid using iterative inverse scattering algorithms or other imaging techniques. The regular structure of unknown scattering elements facilitates a dramatic reduction in the amount of storage and computation required for the FMM, both of which scale linearly with the number of scattering elements. In particular, the use of fast Fourier transforms to compute Green's function convolutions required for neighboring interactions lowers the often-significant cost of finest-level FMM computations and helps mitigate the dependence of FMM cost on finest-level box size. Numerical results demonstrate the efficiency of the composite method as the number of scattering elements in each finest-level box is increased.
The MusIC method: a fast and quasi-optimal solution to the muscle forces estimation problem.
Muller, A; Pontonnier, C; Dumont, G
2018-02-01
The present paper aims at presenting a fast and quasi-optimal method of muscle forces estimation: the MusIC method. It consists in interpolating a first estimation in a database generated offline thanks to a classical optimization problem, and then correcting it to respect the motion dynamics. Three different cost functions - two polynomial criteria and a min/max criterion - were tested on a planar musculoskeletal model. The MusIC method provides a computation frequency approximately 10 times higher compared to a classical optimization problem with a relative mean error of 4% on cost function evaluation.
Wen, Weijia
2011-03-03
A polymerase chain reaction (PCR) device for fast amplification and detection of DNA includes an interchangeable PCR chamber, a temperature control component, and an optical detection system. The DNA amplification is performed on an interchangeable chip with volumes as small as 1.25 µl, while the heating and cooling rate may be as fast as 12.7 °C/second ensuring that the total time needed of only 25 minutes to complete the 35 cycle PCR amplification. The PCR may be performed according to a two-temperature approach for denaturing and annealing (Td and Ta) of DNA with the PCR chip, with which the amplification of male-specific SRY gene marker by utilizing raw saliva may be achieved. The genetic identification may be in-situ detected after PCR by the optical detection system.
International Nuclear Information System (INIS)
Phu, Nguyen Dang; Hoang, Luc Huy; Chen, Xiang-Bai; Kong, Meng-Hong; Wen, Hua-Chiang; Chou, Wu Ching
2015-01-01
We present a study of photocatalytic activities of Bi 2 WO 6 nanoparticles synthesized by fast microwave-assisted method. The photocatalytic activities of the nanoparticles were evaluated by the decolorization of methylene-blue under visible-light-irradiation. Our results show that the surface area of Bi 2 WO 6 nanoparticles plays a major role for improving photocatalytic activity, while visible-light absorption has only a weak effect on photocatalytic activity. This suggests efficient transportation of photo-generated electrons and holes to the oxidation active sites on the surface of nanoparticles, indicating Bi 2 WO 6 nanoparticles synthesized by fast microwave-assisted method are promising for achieving high photocatalytic activity under visible-light-irradiation. - Highlights: • The Bi 2 WO 6 nanoparticles were synthesized via fast microwave-assisted method. • The obtained Bi 2 WO 6 nanoparticles exhibited visible-light absorbance. • The surface area of Bi 2 WO 6 nanoparticles plays major role for improving photocatalytic activity. • The Bi 2 WO 6 nanoparticles are promising for achieving high photocatalytic activity under visible-light-irradiation
Measurement of fast assembly spectra using time-of-flight method
International Nuclear Information System (INIS)
Duquesne, Henry; Rotival, Michel; Schmitt, Andre; Allard, Christian; De Keyser, Albert; Hortsmann, Henri
1975-07-01
Measurement of neutron spectra made in fast subcritical assemblies HUG 3 and PHUG 3 (uranium-graphite and plutonium-graphite) utilizing time-of-flight techniques are described. The matrix were excited by the pulsed neutron source from the BCMN Linac beam impinging on a target of natural uranium. Details of the experimental procedure, safety studies, detector calibration and data reduction are given [fr
Xuli, Wu; Weiyi, He; Ji, Kunmei; Wenpu, Wan; Dongsheng, Hu; Hui, Wu; Xinpin, Luo; Zhigang, Liu
2013-03-01
The ingredient declaration on food labels assumes paramount importance in the protection of food-allergic consumers. China has not implemented Food allergen labeling. A gold immunochromatography assay (GICA) was developed using 2 monoclonal antibodies (mAb) against the milk allergen β-lactoglobulin in this study. The GICA was specific for pure milk samples with a sensitivity of 0.2 ng/mL. Milk protein traces extracted from 110 food products were detected by this method. The labels of 106 were confirmed by our GICA method: 57 food samples originally labeled as containing milk were positive for β-lactoglobulin and 49 food samples labeled as not containing milk were negative for β-lactoglobulin. However, 3 food samples falsely labeled as containing milk were found to contain no β-lactoglobulin whereas 1 food sample labeled as not containing milk actually contained β-lactoglobulin. First, these negatives could be because of the addition of a casein fraction. Second, some countries demand that food manufacturers label all ingredients derived from milk as "containing milk" even though the ingredients contain no detectable milk protein by any method. Our GICA method could thus provide a fast and simple method for semiquantitatation of β-lactoglobulin in foods. The present method provides a fast, simple, semiquantitative method for the determination of milk allergens in foods. © 2013 Institute of Food Technologists®
Revision of FMM-Yukawa: An adaptive fast multipole method for screened Coulomb interactions
Zhang, Bo; Huang, Jingfang; Pitsianis, Nikos P.; Sun, Xiaobai
2010-12-01
FMM-YUKAWA is a mathematical software package primarily for rapid evaluation of the screened Coulomb interactions of N particles in three dimensional space. Since its release, we have revised and re-organized the data structure, software architecture, and user interface, for the purpose of enabling more flexible, broader and easier use of the package. The package and its documentation are available at http://www.fastmultipole.org/, along with a few other closely related mathematical software packages. New version program summaryProgram title: FMM-Yukawa Catalogue identifier: AEEQ_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEQ_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL 2.0 No. of lines in distributed program, including test data, etc.: 78 704 No. of bytes in distributed program, including test data, etc.: 854 265 Distribution format: tar.gz Programming language: FORTRAN 77, FORTRAN 90, and C. Requires gcc and gfortran version 4.4.3 or later Computer: All Operating system: Any Classification: 4.8, 4.12 Catalogue identifier of previous version: AEEQ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2331 Does the new version supersede the previous version?: Yes Nature of problem: To evaluate the screened Coulomb potential and force field of N charged particles, and to evaluate a convolution type integral where the Green's function is the fundamental solution of the modified Helmholtz equation. Solution method: The new version of fast multipole method (FMM) that diagonalizes the multipole-to-local translation operator is applied with the tree structure adaptive to sample particle locations. Reasons for new version: To handle much larger particle ensembles, to enable the iterative use of the subroutines in a solver, and to remove potential contention in assignments for parallelization. Summary of revisions: The software package FMM-Yukawa has been
A fast cross-validation method for alignment of electron tomography images based on Beer-Lambert law
Yan, Rui; Edwards, Thomas J.; Pankratz, Logan M.; Kuhn, Richard J.; Lanman, Jason K.; Liu, Jun; Jiang, Wen
2015-01-01
In electron tomography, accurate alignment of tilt series is an essential step in attaining high-resolution 3D reconstructions. Nevertheless, quantitative assessment of alignment quality has remained a challenging issue, even though many alignment methods have been reported. Here, we report a fast and accurate method, tomoAlignEval, based on the Beer-Lambert law, for the evaluation of alignment quality. Our method is able to globally estimate the alignment accuracy by measuring the goodness of log-linear relationship of the beam intensity attenuations at different tilt angles. Extensive tests with experimental data demonstrated its robust performance with stained and cryo samples. Our method is not only significantly faster but also more sensitive than measurements of tomogram resolution using Fourier shell correlation method (FSCe/o). From these tests, we also conclude that while current alignment methods are sufficiently accurate for stained samples, inaccurate alignments remain a major limitation for high resolution cryo-electron tomography. PMID:26455556
Pieterse, Arwen H; de Vries, Marieke
2013-09-01
Increasingly, patient decision aids and values clarification methods (VCMs) are being developed to support patients in making preference-sensitive health-care decisions. Many VCMs encourage extensive deliberation about options, without solid theoretical or empirical evidence showing that deliberation is advantageous. Research suggests that simple, fast and frugal heuristic decision strategies sometimes result in better judgments and decisions. Durand et al. have developed two fast and frugal heuristic-based VCMs. To critically analyse the suitability of the 'take the best' (TTB) and 'tallying' fast and frugal heuristics in the context of patient decision making. Analysis of the structural similarities between the environments in which the TTB and tallying heuristics have been proven successful and the context of patient decision making and of the potential of these heuristic decision processes to support patient decision making. The specific nature of patient preference-sensitive decision making does not seem to resemble environments in which the TTB and tallying heuristics have proven successful. Encouraging patients to consider less rather than more relevant information potentially even deteriorates their values clarification process. Values clarification methods promoting the use of more intuitive decision strategies may sometimes be more effective. Nevertheless, we strongly recommend further theoretical thinking about the expected value of such heuristics and of other more intuitive decision strategies in this context, as well as empirical assessments of the mechanisms by which inducing such decision strategies may impact the quality and outcome of values clarification. © 2011 John Wiley & Sons Ltd.
International Nuclear Information System (INIS)
Ishiguro, Misako; Higuchi, Kenji
1983-01-01
The finite element method is applied in Galerkin-type approximation to three-dimensional neutron diffusion equations of fast reactors. A hexagonal element scheme is adopted for treating the hexagonal lattice which is typical for fast reactors. The validity of the scheme is verified by applying the scheme as well as alternative schemes to the neutron diffusion calculation of a gas-cooled fast reactor of actual scale. The computed results are compared with corresponding values obtained using the currently applied triangular-element and also with conventional finite difference schemes. The hexagonal finite element scheme is found to yield a reasonable solution to the problem taken up here, with some merit in terms of saving in computing time, but the resulting multiplication factor differs by 1% and the flux by 9% compared with the triangular mesh finite difference scheme. The finite element method, even in triangular element scheme, would appear to incur error in inadmissible amount and which could not be easily eliminated by refining the nodes. (author)
Energy Technology Data Exchange (ETDEWEB)
Orava, J., E-mail: jo316@cam.ac.uk [Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Greer, A.L., E-mail: alg13@cam.ac.uk [Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); WPI-Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)
2015-03-10
Highlights: • Study of ultra-fast DSC applied to the crystallization of glass-forming liquids. • Numerical modeling of DSC traces at heating rates exceeding 10 orders of magnitude. • Identification of three regimes in Kissinger plots. • Elucidation of the effect of liquid fragility on the Kissinger method. • Modeling to study the regime in which crystal growth is thermodynamically limited. - Abstract: Numerical simulation of DSC traces is used to study the validity and limitations of the Kissinger method for determining the temperature dependence of the crystal-growth rate on continuous heating of glasses from the glass transition to the melting temperature. A particular interest is to use the wide range of heating rates accessible with ultra-fast DSC to study systems such as the chalcogenide Ge{sub 2}Sb{sub 2}Te{sub 5} for which fast crystallization is of practical interest in phase-change memory. Kissinger plots are found to show three regimes: (i) at low heating rates the plot is straight, (ii) at medium heating rates the plot is curved as expected from the liquid fragility, and (iii) at the highest heating rates the crystallization rate is thermodynamically limited, and the plot has curvature of the opposite sign. The relative importance of these regimes is identified for different glass-forming systems, considered in terms of the liquid fragility and the reduced glass-transition temperature. The extraction of quantitative information on fundamental crystallization kinetics from Kissinger plots is discussed.
International Nuclear Information System (INIS)
Orava, J.; Greer, A.L.
2015-01-01
Highlights: • Study of ultra-fast DSC applied to the crystallization of glass-forming liquids. • Numerical modeling of DSC traces at heating rates exceeding 10 orders of magnitude. • Identification of three regimes in Kissinger plots. • Elucidation of the effect of liquid fragility on the Kissinger method. • Modeling to study the regime in which crystal growth is thermodynamically limited. - Abstract: Numerical simulation of DSC traces is used to study the validity and limitations of the Kissinger method for determining the temperature dependence of the crystal-growth rate on continuous heating of glasses from the glass transition to the melting temperature. A particular interest is to use the wide range of heating rates accessible with ultra-fast DSC to study systems such as the chalcogenide Ge 2 Sb 2 Te 5 for which fast crystallization is of practical interest in phase-change memory. Kissinger plots are found to show three regimes: (i) at low heating rates the plot is straight, (ii) at medium heating rates the plot is curved as expected from the liquid fragility, and (iii) at the highest heating rates the crystallization rate is thermodynamically limited, and the plot has curvature of the opposite sign. The relative importance of these regimes is identified for different glass-forming systems, considered in terms of the liquid fragility and the reduced glass-transition temperature. The extraction of quantitative information on fundamental crystallization kinetics from Kissinger plots is discussed
A Comparative Study of Analog Voltage-mode Control Methods for Ultra-Fast Tracking Power Supplies
DEFF Research Database (Denmark)
Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.
2007-01-01
This paper presents a theoretical and experimental comparison of the standard PWM/PID voltage-mode control method for single-phase buck converters with two highperformance self-oscillating (a.k.a. sliding mode) control methods. The application considered is ultra-fast tracking power supplies...... (UFTPSs) for RF power amplifiers, where the switching converter needs to track a varying reference voltage precisely and quickly while maintaining low output impedance. The small-signal analyses performed on the different controllers show that the hysteretic-type controller can achieve the highest loop...
Fast and reliable method for computing free-bound emission coefficients for hydrogenic ions
Energy Technology Data Exchange (ETDEWEB)
Sarmiento, A; Canto, J
1985-12-01
An approximate formula for the computation of the free-bound emission coefficient for hydrogenic ions is presented. The approximation is obtained through a manipulation of the (free-bound) Gaunt factor which intentionally distinguish the dependence on frequency from the dependence on temperature and ionic composition. Numerical tests indicate that the derived formula is very precise, fast and easy to use, making the calculation of the free-bound contribution from an ionized region of varying temperature and ionic composition a very simple and time-saving task.
A fast and reliable method for computing free-bound emission coefficients for hydrogenic ions
International Nuclear Information System (INIS)
Sarmiento, A.; Canto, J.
1985-01-01
An approximate formula for the computation of the free-bound emission coefficient for hydrogenic ions is presented. The approximation is obtained through a manipulation of the (free-bound) Gaunt factor which intentionally distinguish the dependence on frequency from the dependence on temperature and ionic composition. Numerical tests indicate that the derived formula is very precise, fast and easy to use, making the calculation of the free-bound contribution from an ionized region of varying temperature and ionic composition a very simple and time-saving task. (author)
Aircraft-borne spectrometry - a fast method for nuclide-specific measurement of soil contamination
International Nuclear Information System (INIS)
Winkelmann, I.; Schweiger, M.; Thomas, M.; Endrulat, H.J.
1991-01-01
An airworthy gamma spectrometer system for fast and large-area, nuclide-specific measurement of the soil contamination is described. The system encompasses an ultrapure germanium detector combined with a computer-controlled multichannel analyser system. The development from the laboratory system to an industrial-scale measuring system is explained. The practical testing is explained and first results are reported, obtained from measuring flights for the nuclide-specific determination of the soil contamination in the free State of Bavaria. (orig.) [de
Error reduction and parameter optimization of the TAPIR method for fast T1 mapping.
Zaitsev, M; Steinhoff, S; Shah, N J
2003-06-01
A methodology is presented for the reduction of both systematic and random errors in T(1) determination using TAPIR, a Look-Locker-based fast T(1) mapping technique. The relations between various sequence parameters were carefully investigated in order to develop recipes for choosing optimal sequence parameters. Theoretical predictions for the optimal flip angle were verified experimentally. Inversion pulse imperfections were identified as the main source of systematic errors in T(1) determination with TAPIR. An effective remedy is demonstrated which includes extension of the measurement protocol to include a special sequence for mapping the inversion efficiency itself. Copyright 2003 Wiley-Liss, Inc.
Core physics design calculation of mini-type fast reactor based on Monte Carlo method
International Nuclear Information System (INIS)
He Keyu; Han Weishi
2007-01-01
An accurate physics calculation model has been set up for the mini-type sodium-cooled fast reactor (MFR) based on MCNP-4C code, then a detailed calculation of its critical physics characteristics, neutron flux distribution, power distribution and reactivity control has been carried out. The results indicate that the basic physics characteristics of MFR can satisfy the requirement and objectives of the core design. The power density and neutron flux distribution are symmetrical and reasonable. The control system is able to make a reliable reactivity balance efficiently and meets the request for long-playing operation. (authors)
Zhao, Feng; Huang, Qingming; Wang, Hao; Gao, Wen
2010-12-01
Similarity measures based on correlation have been used extensively for matching tasks. However, traditional correlation-based image matching methods are sensitive to rotation and scale changes. This paper presents a fast correlation-based method for matching two images with large rotation and significant scale changes. Multiscale oriented corner correlation (MOCC) is used to evaluate the degree of similarity between the feature points. The method is rotation invariant and capable of matching image pairs with scale changes up to a factor of 7. Moreover, MOCC is much faster in comparison with the state-of-the-art matching methods. Experimental results on real images show the robustness and effectiveness of the proposed method.
Directory of Open Access Journals (Sweden)
Taohua Liu
2017-01-01
Full Text Available Fractional advection-dispersion equations, as generalizations of classical integer-order advection-dispersion equations, are used to model the transport of passive tracers carried by fluid flow in a porous medium. In this paper, we develop an implicit finite difference method for fractional advection-dispersion equations with fractional derivative boundary conditions. First-order consistency, solvability, unconditional stability, and first-order convergence of the method are proven. Then, we present a fast iterative method for the implicit finite difference scheme, which only requires storage of O(K and computational cost of O(KlogK. Traditionally, the Gaussian elimination method requires storage of O(K2 and computational cost of O(K3. Finally, the accuracy and efficiency of the method are checked with a numerical example.
Directory of Open Access Journals (Sweden)
Wang Hao
2010-01-01
Full Text Available Similarity measures based on correlation have been used extensively for matching tasks. However, traditional correlation-based image matching methods are sensitive to rotation and scale changes. This paper presents a fast correlation-based method for matching two images with large rotation and significant scale changes. Multiscale oriented corner correlation (MOCC is used to evaluate the degree of similarity between the feature points. The method is rotation invariant and capable of matching image pairs with scale changes up to a factor of 7. Moreover, MOCC is much faster in comparison with the state-of-the-art matching methods. Experimental results on real images show the robustness and effectiveness of the proposed method.
African Journals Online (AJOL)
allergic rhinitis (Fig. 1). Several studies have demonstrated the allergic march from atopic ... Boys appear to be at greater risk of developing the typical progression of allergic .... childhood asthma: lessons from the German. Multicentre Study ...
International Nuclear Information System (INIS)
1989-01-01
This bulletin deals with the brazilian electric power consumption in March 1989, containing data about the total consumption, the growth rates, the special tariffs, and the monthly evolution in each brazilian region. (C.G.C.)
International Nuclear Information System (INIS)
1991-01-01
This bulletin deals with the brazilian electric power consumption in March 1991, containing data about the total consumption, the growth rates, the special tariffs, and the monthly evolution in each brazilian region. (C.G.C.)
International Nuclear Information System (INIS)
1990-01-01
This bulletin deals with the brazilian electric power consumption in March 1990, containing data about the total consumption, the growth rates, the special tariffs, and the monthly evolution in each brazilian region. (C.G.C.)
Determination of the fast neutrons spectra by the Elastic scattering method (n, p)
International Nuclear Information System (INIS)
Elizalde D, J.
1973-01-01
This work consists in determining the fast neutron spectra emitted by a Pu-Be isotopic source. The implemented technique is based in the spectrometry (n, p). This consists in making to fall on a fast neutrons beams (polyenergetic) over a thin film of hydrogenated material, detecting the spectra of emitted protons at a fix angle. The polyethylene film and the used solid state detector are inside of a vacuum chamber. The detector is placed at 30 degree with respect to direction of the incident neutrons beam. The protons spectra is stored in a multichannel. the energy is obtained with the prior calibration of the system. The data processing involves the transformation of the protons spectra observed at the falling on neutrons spectra over the film. The energy of the neutrons is related with that of the protons, according to the collision kinematical equations. The cross section of elastic collision of the neutrons with the hydrogen atoms is obtained from literature. Applying these relations to the observed spectra it is obtained the falling on neutron spectra over the film. (Author)
A fast method for optical simulation of flood maps of light-sharing detector modules
International Nuclear Information System (INIS)
Shi, Han; Du, Dong; Xu, JianFeng; Moses, William W.; Peng, Qiyu
2015-01-01
Optical simulation of the detector module level is highly desired for Position Emission Tomography (PET) system design. Commonly used simulation toolkits such as GATE are not efficient in the optical simulation of detector modules with complicated light-sharing configurations, where a vast amount of photons need to be tracked. We present a fast approach based on a simplified specular reflectance model and a structured light-tracking algorithm to speed up the photon tracking in detector modules constructed with polished finish and specular reflector materials. We simulated conventional block detector designs with different slotted light guide patterns using the new approach and compared the outcomes with those from GATE simulations. While the two approaches generated comparable flood maps, the new approach was more than 200–600 times faster. The new approach has also been validated by constructing a prototype detector and comparing the simulated flood map with the experimental flood map. The experimental flood map has nearly uniformly distributed spots similar to those in the simulated flood map. In conclusion, the new approach provides a fast and reliable simulation tool for assisting in the development of light-sharing-based detector modules with a polished surface finish and using specular reflector materials.
Directory of Open Access Journals (Sweden)
Gunetti Monica
2012-05-01
Full Text Available Abstract Background The quality and safety of advanced therapy products must be maintained throughout their production and quality control cycle to ensure their final use in patients. We validated the cell count method according to the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use and European Pharmacopoeia, considering the tests’ accuracy, precision, repeatability, linearity and range. Methods As the cell count is a potency test, we checked accuracy, precision, and linearity, according to ICH Q2. Briefly our experimental approach was first to evaluate the accuracy of Fast Read 102® compared to the Bürker chamber. Once the accuracy of the alternative method was demonstrated, we checked the precision and linearity test only using Fast Read 102®. The data were statistically analyzed by average, standard deviation and coefficient of variation percentages inter and intra operator. Results All the tests performed met the established acceptance criteria of a coefficient of variation of less than ten percent. For the cell count, the precision reached by each operator had a coefficient of variation of less than ten percent (total cells and under five percent (viable cells. The best range of dilution, to obtain a slope line value very similar to 1, was between 1:8 and 1:128. Conclusions Our data demonstrated that the Fast Read 102® count method is accurate, precise and ensures the linearity of the results obtained in a range of cell dilution. Under our standard method procedures, this assay may thus be considered a good quality control method for the cell count as a batch release quality control test. Moreover, the Fast Read 102® chamber is a plastic, disposable device that allows a number of samples to be counted in the same chamber. Last but not least, it overcomes the problem of chamber washing after use and so allows a cell count in a clean environment such as that in a
International Nuclear Information System (INIS)
Rogers, J.W.
1980-10-01
Fast neutron spectrum measurements were made in a Light Water Reactor (LWR) Pressure Vessel Simulator (PVS) to provide neutron spectral definition required to appropriately perform and interpret neutron dosimetry measurements related to fast neutron damage in LWR-PV steels. Proton-recoil proportional counter methods using hydrogen and methane gas-filled detectors were applied to obtain the proton spectra from which the neutron spectra were derived. Cylindrical and spherical geometry detectors were used to cover the neutron energy range between 50 keV and 2 MeV. Results show that the neutron spectra shift in energy distribution toward lower energy between the front and back of a PVS. The relative neutron flux densities increase in this energy range with increasing thickness of the steel. Neutron spectrum fine structure shapes and changes are observed. These results should assist in the generation of more accurate effective cross sections and fluences for use in LWR-PV fast neutron dosimetry and materials damage analyses
Directory of Open Access Journals (Sweden)
Syafii
2017-03-01
Full Text Available This paper presents the assessment of fast decoupled load flow computation using three linear system solver scheme. The full matrix version of the fast decoupled load flow based on XB methods used in this study. The numerical investigations are carried out on the small and large test systems. The execution time of small system such as IEEE 14, 30, and 57 are very fast, therefore the computation time can not be compared for these cases. Another cases IEEE 118, 300 and TNB 664 produced significant execution speedup. The superLU factorization sparse matrix solver has best performance and speedup of load flow solution as well as in contigency analysis. The invers full matrix solver can solved only for IEEE 118 bus test system in 3.715 second and for another cases take too long time. However for superLU factorization linear solver can solved all of test system in 7.832 second for a largest of test system. Therefore the superLU factorization linear solver can be a viable alternative applied in contingency analysis.
Serang, Oliver
2015-08-01
Observations depending on sums of random variables are common throughout many fields; however, no efficient solution is currently known for performing max-product inference on these sums of general discrete distributions (max-product inference can be used to obtain maximum a posteriori estimates). The limiting step to max-product inference is the max-convolution problem (sometimes presented in log-transformed form and denoted as "infimal convolution," "min-convolution," or "convolution on the tropical semiring"), for which no O(k log(k)) method is currently known. Presented here is an O(k log(k)) numerical method for estimating the max-convolution of two nonnegative vectors (e.g., two probability mass functions), where k is the length of the larger vector. This numerical max-convolution method is then demonstrated by performing fast max-product inference on a convolution tree, a data structure for performing fast inference given information on the sum of n discrete random variables in O(nk log(nk)log(n)) steps (where each random variable has an arbitrary prior distribution on k contiguous possible states). The numerical max-convolution method can be applied to specialized classes of hidden Markov models to reduce the runtime of computing the Viterbi path from nk(2) to nk log(k), and has potential application to the all-pairs shortest paths problem.
International Nuclear Information System (INIS)
Sunardi; Samin Prihatin
2010-01-01
Validation and uncertainty estimation of Fast Neutron Activation Analysis (FNAA) method for Cu, Fe, Al, Si elements in sediment samples has been conduced. The aim of the research is to confirm whether FNAA method is still matches to ISO/lEC 17025-2005 standard. The research covered the verification, performance, validation of FNM and uncertainty estimation. Standard of SRM 8704 and sediments were weighted for certain weight and irradiated with 14 MeV fast neutron and then counted using gamma spectrometry. The result of validation method for Cu, Fe, Al, Si element showed that the accuracy were in the range of 95.89-98.68 %, while the precision were in the range 1.13-2.29 %. The result of uncertainty estimation for Cu, Fe, Al, and Si were 2.67, 1.46, 1.71 and 1.20 % respectively. From this data, it can be concluded that the FNM method is still reliable and valid for element contents analysis in samples, because the accuracy is up to 95 % and the precision is under 5 %, while the uncertainty are relatively small and suitable for the range 95 % level of confidence where the uncertainty maximum is 5 %. (author)
International Nuclear Information System (INIS)
Cruceru, I.; Sandu, M.; Cruceru, M.
1994-01-01
A method for measuring and evaluation of doses and dose equivalent rate in mixed gamma- neutron fields is discussed in this paper. The method is basedon a double detector system consist of an ionization chamber with components made from a plastic scintillator, coupled to on photomultiplier. Generally the radiation fields around accelerators are complex, often consisting of many different ionizing radiations extending over a broad range of energies. This method solve two major difficulties: determination of response functions of radiation detectors; interpretation of measurement and determination of accuracy. The discrimination gamma-fast neutrons is assured directly without a pulse shape discrimination circuit. The method is applied to mixed fields in which particle energies are situated in the energy range under 20 MeV and an izotropic emision (Φ=10 4 -10 11 n.s -1 ). The dose equivalent rates explored is 0.01mSV--0.1SV
Gunetti, Monica; Castiglia, Sara; Rustichelli, Deborah; Mareschi, Katia; Sanavio, Fiorella; Muraro, Michela; Signorino, Elena; Castello, Laura; Ferrero, Ivana; Fagioli, Franca
2012-05-31
The quality and safety of advanced therapy products must be maintained throughout their production and quality control cycle to ensure their final use in patients. We validated the cell count method according to the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use and European Pharmacopoeia, considering the tests' accuracy, precision, repeatability, linearity and range. As the cell count is a potency test, we checked accuracy, precision, and linearity, according to ICH Q2. Briefly our experimental approach was first to evaluate the accuracy of Fast Read 102® compared to the Bürker chamber. Once the accuracy of the alternative method was demonstrated, we checked the precision and linearity test only using Fast Read 102®. The data were statistically analyzed by average, standard deviation and coefficient of variation percentages inter and intra operator. All the tests performed met the established acceptance criteria of a coefficient of variation of less than ten percent. For the cell count, the precision reached by each operator had a coefficient of variation of less than ten percent (total cells) and under five percent (viable cells). The best range of dilution, to obtain a slope line value very similar to 1, was between 1:8 and 1:128. Our data demonstrated that the Fast Read 102® count method is accurate, precise and ensures the linearity of the results obtained in a range of cell dilution. Under our standard method procedures, this assay may thus be considered a good quality control method for the cell count as a batch release quality control test. Moreover, the Fast Read 102® chamber is a plastic, disposable device that allows a number of samples to be counted in the same chamber. Last but not least, it overcomes the problem of chamber washing after use and so allows a cell count in a clean environment such as that in a Cell Factory. In a good manufacturing practice setting the disposable
A fast numerical method for ideal fluid flow in domains with multiple stirrers
Nasser, Mohamed M. S.; Green, Christopher C.
2018-03-01
A collection of arbitrarily-shaped solid objects, each moving at a constant speed, can be used to mix or stir ideal fluid, and can give rise to interesting flow patterns. Assuming these systems of fluid stirrers are two-dimensional, the mathematical problem of resolving the flow field—given a particular distribution of any finite number of stirrers of specified shape and speed—can be formulated as a Riemann-Hilbert (R-H) problem. We show that this R-H problem can be solved numerically using a fast and accurate algorithm for any finite number of stirrers based around a boundary integral equation with the generalized Neumann kernel. Various systems of fluid stirrers are considered, and our numerical scheme is shown to handle highly multiply connected domains (i.e. systems of many fluid stirrers) with minimal computational expense.
International Nuclear Information System (INIS)
Chang, Chi-Jung; Wang, Chih-Feng; Chen, Jem-Kun; Hsieh, Chih-Chiao; Chen, Po-An
2013-01-01
An approach is developed for the fast formation of a hydrophilic pattern on superhydrophobic substrates with good contrast due to the large wettability contrast between superhydrophobic and superhydrophilic areas. It can be used for forming a polymer pattern with reactive functional groups. TiO 2 nanoparticles were grafted with long alkyl chains and then coated on substrates to produce superhydrophobic films. Photocatalytic degradation of the grafted alkyl chains was effected with UV light irradiation and resulted in transition from superhydrophobicity to superhydrophilicity. After UV light irradiation through a mask for 30 s, dyes or polymers were adsorbed on the photoinduced superhydrophilic areas to make micropatterns. The photoinduced superhydrophilic switching properties can be tuned by changing the alkyl chain length. The ninhydrin assay was adapted to identify free amino groups of polymers on the patterned area. Polymer patterns with free amino groups can be achieved.
International Nuclear Information System (INIS)
Nakanishi, Hideya; Imazu, Setsuo; Ohsuna, Masaki
2012-01-01
To deal with endless data streams acquired in LHD steady-state experiments, the LHD data acquisition system was designed with a simple concept that divides a long pulse into a consecutive series of 10-s “subshots”. Latest digitizers applying high-speed PCI-Express technology, however, output nonstop gigabyte per second data streams whose subshot intervals would be extremely long if 10-s rule was applied. These digitizers need shorter subshot intervals, less than 10-s long. In contrast, steady-state fusion plants need uninterrupted monitoring of the environment and device soundness. They adopt longer subshot lengths of either 10 min or 1 day. To cope with both uninterrupted monitoring and ultra-fast diagnostics, the ability to vary the subshot length according to the type of operation is required. In this study, a design modification that enables variable subshot lengths was implemented and its practical effectiveness in LHD was verified. (author)
U.S. Sodium Fast Reactor Codes and Methods: Current Capabilities and Path Forward
Energy Technology Data Exchange (ETDEWEB)
Brunett, A. J.; Fanning, T. H.
2017-06-26
The United States has extensive experience with the design, construction, and operation of sodium cooled fast reactors (SFRs) over the last six decades. Despite the closure of various facilities, the U.S. continues to dedicate research and development (R&D) efforts to the design of innovative experimental, prototype, and commercial facilities. Accordingly, in support of the rich operating history and ongoing design efforts, the U.S. has been developing and maintaining a series of tools with capabilities that envelope all facets of SFR design and safety analyses. This paper provides an overview of the current U.S. SFR analysis toolset, including codes such as SAS4A/SASSYS-1, MC2-3, SE2-ANL, PERSENT, NUBOW-3D, and LIFE-METAL, as well as the higher-fidelity tools (e.g. PROTEUS) being integrated into the toolset. Current capabilities of the codes are described and key ongoing development efforts are highlighted for some codes.
Fast Missile Boat Project Planning using CPM and What If Analysis Method
Silvianita; Firmansyah, R.; Rosyid, D. M.; Suntoyo; Chamelia, D. M.
2018-03-01
This paper discusses analysis of fast ship missile project planning with CPM and What If analysis.The poor performance can cause project delay and cost overruns, these two things often occur in a project management. Scheduling has an important role to control the project. Good scheduling is required because it will affect the product quality. Scheduling is useful to manage the activities so that the project completion time can be as short as possible and it is used to determine the costs of the project are in optimum condition. The alternatives that can be used to overcome the delay project namely increasing labor and equipment.Project planning can be done to determine whether the project is already in an optimum condition. Alternatives that can be used to overcome the delay in the project is to increase labor and equipment, the next is to look for the optimum solution taking into account the duration and gain of each alternative.
Energy Technology Data Exchange (ETDEWEB)
Chang, Chi-Jung, E-mail: changcj@fcu.edu.tw [Department of Chemical Engineering, Feng Chia University, 100, Wenhwa Road, Seatwen, Taichung 407, Taiwan (China); Wang, Chih-Feng [Department of Materials Science and Engineering, I-Shou University, 1, Syuecheng Road, Dashu District, Kaohsiung 840, Taiwan (China); Chen, Jem-Kun [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Road, Taipei 106, Taiwan (China); Hsieh, Chih-Chiao; Chen, Po-An [Department of Chemical Engineering, Feng Chia University, 100, Wenhwa Road, Seatwen, Taichung 407, Taiwan (China)
2013-12-01
An approach is developed for the fast formation of a hydrophilic pattern on superhydrophobic substrates with good contrast due to the large wettability contrast between superhydrophobic and superhydrophilic areas. It can be used for forming a polymer pattern with reactive functional groups. TiO{sub 2} nanoparticles were grafted with long alkyl chains and then coated on substrates to produce superhydrophobic films. Photocatalytic degradation of the grafted alkyl chains was effected with UV light irradiation and resulted in transition from superhydrophobicity to superhydrophilicity. After UV light irradiation through a mask for 30 s, dyes or polymers were adsorbed on the photoinduced superhydrophilic areas to make micropatterns. The photoinduced superhydrophilic switching properties can be tuned by changing the alkyl chain length. The ninhydrin assay was adapted to identify free amino groups of polymers on the patterned area. Polymer patterns with free amino groups can be achieved.
Study of the propagation of fast neutrons in water, by Monte-Carlo methods
International Nuclear Information System (INIS)
Lafore, P.; Lattes, R.; Millot, J.P.
1958-01-01
We have studied the propagation in water of neutrons from mono-directional plane sources with energies ranging from 300 keV to 19,66 MeV, placed in an infinite water medium. The exact paths of a number of neutrons are determined, taking into account the microscopic sections, assuming that inelastic collisions of the neutrons on oxygen are absorptions, and neglecting the loss of energy by elastic collisions on oxygen. The neutron lifetimes have been made use of to study the propagation of neutrons from fission sources, Po-Be, Po-B and Ra-Be, as well as the reflection of fast neutrons on a semi-infinite water medium. We have taken complete account of the first collision in order to improve the precision of the results. The calculations were carried out by Mrs J. VASSEUR and Mr A. GUILLOU. (author) [fr
Jami, L; Lan-Couton, D; Malmgren, K; Petit, J
1978-07-01
The glycogen-depletion method was used to investigate the motor supply to tenuissimus with respect to the presence of fast beta axons and to assess the total proportion of both fast and slow beta-innervated spindles in this muscle. In a first series of 5 expts., groups of motor axons with conduction velocities higher than 85 m/s were repetitively stimulated so as to produce glycogen depletion in the muscle fibres they innervated. The whole muscle was then quick-frozen, serially cut, stained to demonstrate glycogen and examined for intrafusal glycogen depletion. Zones of glycogen depletion were found in 16 of the 46 examined spindles; they were most frequently located in the longest of the chain intrafusal muscle fibres. Since it is known that there are no purely fusimotor axons to tenuissimus with conduction velocities above 50 m/s, it was concluded that beta axons are present among the fastest axons to this muscle. In a second series of 5 expts. as many motor axons as possible with conduction velocities above 60 m/s were stimulated. Zones of glycogen depletion were found in 19 of the 47 examined spindles. They affected chain fibres in about half of the instances and bag1 fibers in the others. As this latter location is characteristic of slow dynamic beta axons, it was concluded that both slow and fast beta axons occur regularly in the motor supply to tenuissimus. beta-innervation is present in at least 40% of tenuissimus spindles with almost no convergence of fast and slow beta axons onto the same spindle.
The lead cooled fast reactor benchmark Brest-300: analysis with sensitivity method
International Nuclear Information System (INIS)
Smirnov, V.; Orlov, V.; Mourogov, A.; Lecarpentier, D.; Ivanova, T.
2005-01-01
Lead cooled fast neutrons reactor is one of the most interesting candidates for the development of atomic energy. BREST-300 is a 300 MWe lead cooled fast reactor developed by the NIKIET (Russia) with a deterministic safety approach which aims to exclude reactivity margins greater than the delayed neutron fraction. The development of innovative reactors (lead coolant, nitride fuel...) and fuel cycles with new constraints such as cycle closure or actinide burning, requires new technologies and new nuclear data. In this connection, the tool and neutron data used for the calculational analysis of reactor characteristics requires thorough validation. NIKIET developed a reactor benchmark fitting of design type calculational tools (including neutron data). In the frame of technical exchanges between NIKIET and EDF (France), results of this benchmark calculation concerning the principal parameters of fuel evolution and safety parameters has been inter-compared, in order to estimate the uncertainties and validate the codes for calculations of this new kind of reactors. Different codes and cross-sections data have been used, and sensitivity studies have been performed to understand and quantify the uncertainties sources.The comparison of results shows that the difference on k eff value between ERANOS code with ERALIB1 library and the reference is of the same order of magnitude than the delayed neutron fraction. On the other hand, the discrepancy is more than twice bigger if JEF2.2 library is used with ERANOS. Analysis of discrepancies in calculation results reveals that the main effect is provided by the difference of nuclear data, namely U 238 , Pu 239 fission and capture cross sections and lead inelastic cross sections
International Nuclear Information System (INIS)
Marrel, A.; Marie, N.; De Lozzo, M.
2015-01-01
Within the framework of the generation IV Sodium Fast Reactors, the safety in case of severe accidents is assessed. From this statement, CEA has developed a new physical tool to model the accident initiated by the Total Instantaneous Blockage (TIB) of a sub-assembly. This TIB simulator depends on many uncertain input parameters. This paper aims at proposing a global methodology combining several advanced statistical techniques in order to perform a global sensitivity analysis of this TIB simulator. The objective is to identify the most influential uncertain inputs for the various TIB outputs involved in the safety analysis. The proposed statistical methodology combining several advanced statistical techniques enables to take into account the constraints on the TIB simulator outputs (positivity constraints) and to deal simultaneously with various outputs. To do this, a space-filling design is used and the corresponding TIB model simulations are performed. Based on this learning sample, an efficient constrained Gaussian process metamodel is fitted on each TIB model outputs. Then, using the metamodels, classical sensitivity analyses are made for each TIB output. Multivariate global sensitivity analyses based on aggregated indices are also performed, providing additional valuable information. Main conclusions on the influence of each uncertain input are derived. - Highlights: • Physical-statistical tool for Sodium Fast Reactors TIB accident. • 27 uncertain parameters (core state, lack of physical knowledge) are highlighted. • Constrained Gaussian process efficiently predicts TIB outputs (safety criteria). • Multivariate sensitivity analyses reveal that three inputs are mainly influential. • The type of corium propagation (thermal or hydrodynamic) is the most influential
Method of effecting fast turbine valving for improvement of power system stability
International Nuclear Information System (INIS)
Park, R.H.
1981-01-01
As a improved way of effecting fast valving of turbines of power system steam-electric generating units for the purpose of improving the stability of power transmission over transmission circuits to which their generators make connection, when stability is threatened by line faults and certain other stability endangering events, the heretofore employed and/or advocated practice of automatically closing intercept valves at fastest available closing speed in response to a fast valving signal, and thereafter automatically fully reopening them in a matter of seconds, is modified by providing to reopen the valves only partially to and thereafter retain them at a preset partially open position. For best results the process of what can be termed sustained partial reopening is so effected as to result in its completion within a fraction of a second following the peak of the first forward swing of the generator rotor. Control valves may be either held open, or automatically fully or partly closed and thereafter fully opened in a preprogrammed manner, or automatically moved to and thereafter held in a partly closed position, by means of a preprogrammed process of repositioning in which the valves may optionally be first fully or partly closed and thereafter partly reopened. Avoidance of discharge of steam through high pressure safety valves can be had with use of suitably controlled power operated valves that discharge steam to the condenser or to atmosphere. Where there is an intermediate pressure turbine that is supplied with superheated steam, use of sustained partial control valve closure, if employed, is supplemented by provision for reduction of rate of heat release within the steam generator in order to protect the reheater from overheating. As a way to restrict increase of reheat pressure of fossil fuel installations, and to minimize increase in the msr (Moisture separator-reheater) pressure of nuclear units, provision is optionally made of normally closed by-pass v
International Nuclear Information System (INIS)
Koskinas, M.F.
1979-01-01
Experimental and theoretical details of the foil activation method applied to neutrons flux measurements at the IEA-R1 reactor are presented. The thermal - and epithermal - neutron flux were determined form activation measurements of gold, cobalt and manganese foils; and for the fast neutron flux determination, aluminum, iron and nickel foils were used. The measurements of the activity induced in the metal foils were performed using a Ge-Li gamma spectrometry system. In each energy range of the reactor neutron spectrum, the agreement among the experimental flux values obtained using the three kind of materials, indicates the consistency of the theoretical approach and of the nuclear parameters selected. (Author) [pt
Energy Technology Data Exchange (ETDEWEB)
Chang, Hyejin; Jeong, Sinyoung; Ko, Eunbyeol; Jeong, Dae Hong, E-mail: yslee@snu.ac.kr, E-mail: debobkr@gmail.com, E-mail: jeongdh@snu.ac.kr [Department of Chemistry Education, Seoul National University, Seoul 151-742 (Korea, Republic of); Kang, Homan [Interdisciplinary Program in Nano-Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Yoon-Sik, E-mail: yslee@snu.ac.kr, E-mail: debobkr@gmail.com, E-mail: jeongdh@snu.ac.kr [Interdisciplinary Program in Nano-Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, Ho-Young, E-mail: yslee@snu.ac.kr, E-mail: debobkr@gmail.com, E-mail: jeongdh@snu.ac.kr [Department of Nuclear Medicine, Seoul National University Bundang Hospital, Seongnam 463-707 (Korea, Republic of)
2015-05-15
Surface-enhanced Raman scattering techniques have been widely used for bioanalysis due to its high sensitivity and multiplex capacity. However, the point-scanning method using a micro-Raman system, which is the most common method in the literature, has a disadvantage of extremely long measurement time for on-chip immunoassay adopting a large chip area of approximately 1-mm scale and confocal beam point of ca. 1-μm size. Alternative methods such as sampled spot scan with high confocality and large-area scan method with enlarged field of view and low confocality have been utilized in order to minimize the measurement time practically. In this study, we analyzed the two methods in respect of signal-to-noise ratio and sampling-led signal fluctuations to obtain insights into a fast and reliable readout strategy. On this basis, we proposed a methodology for fast and reliable quantitative measurement of the whole chip area. The proposed method adopted a raster scan covering a full area of 100 μm × 100 μm region as a proof-of-concept experiment while accumulating signals in the CCD detector for single spectrum per frame. One single scan with 10 s over 100 μm × 100 μm area yielded much higher sensitivity compared to sampled spot scanning measurements and no signal fluctuations attributed to sampled spot scan. This readout method is able to serve as one of key technologies that will bring quantitative multiplexed detection and analysis into practice.
International Nuclear Information System (INIS)
Toshio, S.; Kazuo, A.
1983-01-01
A model for calculating the power distribution and the control rod worth in fast reactors has been developed. This model is based on the influence function method. The characteristics of the model are as follows: 1. Influence functions for any changes in the control rod insertion ratio are expressed by using an influence function for an appropriate control rod insertion in order to reduce the computer memory size required for the method. 2. A control rod worth is calculated on the basis of a one-group approximation in which cross sections are generated by bilinear (flux-adjoint) weighting, not the usual flux weighting, in order to reduce the collapse error. 3. An effective neutron multiplication factor is calculated by adjoint weighting in order to reduce the effect of the error in the one-group flux distribution. The results obtained in numerical examinations of a prototype fast reactor indicate that this method is suitable for on-line core performance evaluation because of a short computing time and a small memory size
International Nuclear Information System (INIS)
Sanda, T.; Azekura, K.
1983-01-01
A model for calculating the power distribution and the control rod worth in fast reactors has been developed. This model is based on the influence function method. The characteristics of the model are as follows: Influence functions for any changes in the control rod insertion ratio are expressed by using an influence function for an appropriate control rod insertion in order to reduce the computer memory size required for the method. A control rod worth is calculated on the basis of a one-group approximation in which cross sections are generated by bilinear (flux-adjoint) weighting, not the usual flux weighting, in order to reduce the collapse error. An effective neutron multiplication factor is calculated by adjoint weighting in order to reduce the effect of the error in the one-group flux distribution. The results obtained in numerical examinations of a prototype fast reactor indicate that this method is suitable for on-line core performance evaluation because of a short computing time and a small memory size
International Nuclear Information System (INIS)
Baszczyk, M.; Dorosz, P.; Glab, S.; Kucewicz, W.; Mik, L.; Sapor, M.
2016-01-01
The paper presents an implementation of fully differential readout method for Silicon Photomultipliers (SiPM). Front-end electronics consists of a fast and slow path. The former creates the trigger signal while the latter produces a pulse of width proportional to the input charge. The fast shaper generates unipolar pulse and utilizes the pole-zero cancelation circuit. The peaking time for single photoelectron is equal to 3.6 ns and the FWHM is 3.8 ns. The pulse width of the Charge to Time Converter (QTC) depends on the number of photons entering the SiPM at the moment of measurement. The QTC response is nonlinear but it allows us to work with signals in a wide dynamic range. The proposed readout method is effective in measurements of random signals where frequent events tend to pile-up. Thermal generation and afterpulses have a strong influence on the width of pulses from QTC. The proposed method enables us to distinguish those overlapping signals and get the reliable information on the number of detected photons.
Energy Technology Data Exchange (ETDEWEB)
Baszczyk, M., E-mail: baszczyk@agh.edu.pl [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); Dorosz, P.; Glab, S.; Kucewicz, W. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); Mik, L. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland); State Higher Vocational School, Tarnow (Poland); Sapor, M. [AGH University of Science and Technology, Department of Electronics, Krakow (Poland)
2016-07-11
The paper presents an implementation of fully differential readout method for Silicon Photomultipliers (SiPM). Front-end electronics consists of a fast and slow path. The former creates the trigger signal while the latter produces a pulse of width proportional to the input charge. The fast shaper generates unipolar pulse and utilizes the pole-zero cancelation circuit. The peaking time for single photoelectron is equal to 3.6 ns and the FWHM is 3.8 ns. The pulse width of the Charge to Time Converter (QTC) depends on the number of photons entering the SiPM at the moment of measurement. The QTC response is nonlinear but it allows us to work with signals in a wide dynamic range. The proposed readout method is effective in measurements of random signals where frequent events tend to pile-up. Thermal generation and afterpulses have a strong influence on the width of pulses from QTC. The proposed method enables us to distinguish those overlapping signals and get the reliable information on the number of detected photons.
International Nuclear Information System (INIS)
Ansarifar, G.R.; Nasrabadi, M.N.; Hassanvand, R.
2016-01-01
Highlights: • We present a S.M.C. system based on the S.M.O for control of a fast reactor power. • A S.M.O has been developed to estimate the density of delayed neutron precursor. • The stability analysis has been given by means Lyapunov approach. • The control system is guaranteed to be stable within a large range. • The comparison between S.M.C. and the conventional PID controller has been done. - Abstract: In this paper, a nonlinear controller using sliding mode method which is a robust nonlinear controller is designed to control a fast nuclear reactor. The reactor core is simulated based on the point kinetics equations and one delayed neutron group. Considering the limitations of the delayed neutron precursor density measurement, a sliding mode observer is designed to estimate it and finally a sliding mode control based on the sliding mode observer is presented. The stability analysis is given by means Lyapunov approach, thus the control system is guaranteed to be stable within a large range. Sliding Mode Control (SMC) is one of the robust and nonlinear methods which have several advantages such as robustness against matched external disturbances and parameter uncertainties. The employed method is easy to implement in practical applications and moreover, the sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability.
Directory of Open Access Journals (Sweden)
Treena Basu
2015-10-01
Full Text Available This paper proposes an approach for the space-fractional diffusion equation in one dimension. Since fractional differential operators are non-local, two main difficulties arise after discretization and solving using Gaussian elimination: how to handle the memory requirement of O(N2 for storing the dense or even full matrices that arise from application of numerical methods and how to manage the significant computational work count of O(N3 per time step, where N is the number of spatial grid points. In this paper, a fast iterative finite difference method is developed, which has a memory requirement of O(N and a computational cost of O(N logN per iteration. Finally, some numerical results are shown to verify the accuracy and efficiency of the new method.
Spötl, Christoph
2005-09-01
The stable carbon isotopic composition of dissolved inorganic carbon (delta13C(DIC)) is traditionally determined using either direct precipitation or gas evolution methods in conjunction with offline gas preparation and measurement in a dual-inlet isotope ratio mass spectrometer. A gas evolution method based on continuous-flow technology is described here, which is easy to use and robust. Water samples (100-1500 microl depending on the carbonate alkalinity) are injected into He-filled autosampler vials in the field and analysed on an automated continuous-flow gas preparation system interfaced to an isotope ratio mass spectrometer. Sample analysis time including online preparation is 10 min and overall precision is 0.1 per thousand. This method is thus fast and can easily be automated for handling large sample batches.
Fuguet, Elisabet; Ràfols, Clara; Bosch, Elisabeth; Rosés, Martí
2009-04-24
A new and fast method to determine acidity constants of monoprotic weak acids and bases by capillary zone electrophoresis based on the use of an internal standard (compound of similar nature and acidity constant as the analyte) has been developed. This method requires only two electrophoretic runs for the determination of an acidity constant: a first one at a pH where both analyte and internal standard are totally ionized, and a second one at another pH where both are partially ionized. Furthermore, the method is not pH dependent, so an accurate measure of the pH of the buffer solutions is not needed. The acidity constants of several phenols and amines have been measured using internal standards of known pK(a), obtaining a mean deviation of 0.05 pH units compared to the literature values.
Methods of fast, multiple-point in vivo T1 determination
International Nuclear Information System (INIS)
Zhang, Y.; Spigarelli, M.; Fencil, L.E.; Yeung, H.N.
1989-01-01
Two methods of rapid, multiple-point determination of T1 in vivo have been evaluated with a phantom consisting of vials of gel in different Mn + + concentrations. The first method was an inversion-recovery- on-the-fly technique, and the second method used a variable- tip-angle (α) progressive saturation with two sub- sequences of different repetition times. In the first method, 1/T1 was evaluated by an exponential fit. In the second method, 1/T1 was obtained iteratively with a linear fit and then readjusted together with α to a model equation until self-consistency was reached
Fast egg collection method greatly improves randomness of egg sampling in Drosophila melanogaster
DEFF Research Database (Denmark)
Schou, Mads Fristrup
2013-01-01
When obtaining samples for population genetic studies, it is essential that the sampling is random. For Drosophila, one of the crucial steps in sampling experimental flies is the collection of eggs. Here an egg collection method is presented, which randomizes the eggs in a water column...... and diminishes environmental variance. This method was compared with a traditional egg collection method where eggs are collected directly from the medium. Within each method the observed and expected standard deviations of egg-to-adult viability were compared, whereby the difference in the randomness...... and to obtain a representative collection of genotypes, the method presented here is strongly recommended when collecting eggs from Drosophila....
International Nuclear Information System (INIS)
Cameron, R.
2013-01-01
Sustainability was discussed in terms of the social, environment and economic perspectives, which arise from the original Brundtland definition of sustainability. The panel presented their perspectives of the need to move towards a sustainable future, involving better use of uranium, reductions in high-level radioactive waste, safe, secure and economic operation of nuclear reactors and the fuel cycle. In all cases, it was considered that sustainability in the long-term must involve fast reactors and a closed nuclear fuel cycle, although both Korea and the IAEA pointed out that these are clearly national decisions and there will not be a single solution for all countries
International Nuclear Information System (INIS)
Crevoisier, D.; Voltz, M.; Chanzy, A.
2009-01-01
Ross [Ross PJ. Modeling soil water and solute transport - fast, simplified numerical solutions. Agron J 2003;95:1352-61] developed a fast, simplified method for solving Richards' equation. This non-iterative 1D approach, using Brooks and Corey [Brooks RH, Corey AT. Hydraulic properties of porous media. Hydrol. papers, Colorado St. Univ., Fort Collins: 1964] hydraulic functions, allows a significant reduction in computing time while maintaining the accuracy of the results. The first aim of this work is to confirm these results in a more extensive set of problems, including those that would lead to serious numerical difficulties for the standard numerical method. The second aim is to validate a generalisation of the Ross method to other mathematical representations of hydraulic functions. The Ross method is compared with the standard finite element model, Hydrus-1D [Simunek J, Sejna M, Van Genuchten MTh. The HYDRUS-1D and HYDRUS-2D codes for estimating unsaturated soil hydraulic and solutes transport parameters. Agron Abstr 357; 1999]. Computing time, accuracy of results and robustness of numerical schemes are monitored in 1D simulations involving different types of homogeneous soils, grids and hydrological conditions. The Ross method associated with modified Van Genuchten hydraulic functions [Vogel T, Cislerova M. On the reliability of unsaturated hydraulic conductivity calculated from the moisture retention curve. Transport Porous Media 1988:3:1-15] proves in every tested scenario to be more robust numerically, and the compromise of computing time/accuracy is seen to be particularly improved on coarse grids. Ross method run from 1.25 to 14 times faster than Hydrus-1D. (authors)
Energy Technology Data Exchange (ETDEWEB)
Magome, Taiki [Department of Radiological Sciences, Faculty of Health Sciences, Komazawa University, Tokyo (Japan); Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Haga, Akihiro [Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Takahashi, Yutaka [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology, Osaka University, Osaka (Japan); Nakagawa, Keiichi [Department of Radiology, The University of Tokyo Hospital, Tokyo (Japan); Dusenbery, Kathryn E. [Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Hui, Susanta K., E-mail: shui@coh.org [Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota (United States); Department of Therapeutic Radiology, University of Minnesota, Minneapolis, Minnesota (United States); Department of Radiation Oncology and Beckman Research Institute, City of Hope, Duarte, California (United States)
2016-11-01
Purpose: Megavoltage computed tomographic (MVCT) imaging has been widely used for the 3-dimensional (3-D) setup of patients treated with helical tomotherapy (HT). One drawback of MVCT is its very long imaging time, the result of slow couch speeds of approximately 1 mm/s, which can be difficult for the patient to tolerate. We sought to develop an MVCT imaging method allowing faster couch speeds and to assess its accuracy for image guidance for HT. Methods and Materials: Three cadavers were scanned 4 times with couch speeds of 1, 2, 3, and 4 mm/s. The resulting MVCT images were reconstructed using an iterative reconstruction (IR) algorithm with a penalty term of total variation and with a conventional filtered back projection (FBP) algorithm. The MVCT images were registered with kilovoltage CT images, and the registration errors from the 2 reconstruction algorithms were compared. This fast MVCT imaging was tested in 3 cases of total marrow irradiation as a clinical trial. Results: The 3-D registration errors of the MVCT images reconstructed with the IR algorithm were smaller than the errors of images reconstructed with the FBP algorithm at fast couch speeds (2, 3, 4 mm/s). The scan time and imaging dose at a speed of 4 mm/s were reduced to 30% of those from a conventional coarse mode scan. For the patient imaging, faster MVCT (3 mm/s couch speed) scanning reduced the imaging time and still generated images useful for anatomic registration. Conclusions: Fast MVCT with the IR algorithm is clinically feasible for large 3-D target localization, which may reduce the overall time for the treatment procedure. This technique may also be useful for calculating daily dose distributions or organ motion analyses in HT treatment over a wide area. Automated integration of this imaging is at least needed to further assess its clinical benefits.
Venom On-a-Chip: A Fast and Efficient Method for Comparative Venomics.
Zancolli, Giulia; Sanz, Libia; Calvete, Juan J; Wüster, Wolfgang
2017-05-28
Venom research has attracted an increasing interest in disparate fields, from drug development and pharmacology, to evolutionary biology and ecology, and rational antivenom production. Advances in "-omics" technologies have allowed the characterization of an increasing number of animal venoms, but the methodology currently available is suboptimal for large-scale comparisons of venom profiles. Here, we describe a fast, reproducible and semi-automated protocol for investigating snake venom variability, especially at the intraspecific level, using the Agilent Bioanalyzer on-chip technology. Our protocol generated a phenotype matrix which can be used for robust statistical analysis and correlations of venom variation with ecological correlates, or other extrinsic factors. We also demonstrate the ease and utility of combining on-chip technology with previously fractionated venoms for detection of specific individual toxin proteins. Our study describes a novel strategy for rapid venom discrimination and analysis of compositional variation at multiple taxonomic levels, allowing researchers to tackle evolutionary questions and unveiling the drivers of the incredible biodiversity of venoms.
Shi, Yingzhong; Chung, Fu-Lai; Wang, Shitong
2015-09-01
Recently, a time-adaptive support vector machine (TA-SVM) is proposed for handling nonstationary datasets. While attractive performance has been reported and the new classifier is distinctive in simultaneously solving several SVM subclassifiers locally and globally by using an elegant SVM formulation in an alternative kernel space, the coupling of subclassifiers brings in the computation of matrix inversion, thus resulting to suffer from high computational burden in large nonstationary dataset applications. To overcome this shortcoming, an improved TA-SVM (ITA-SVM) is proposed using a common vector shared by all the SVM subclassifiers involved. ITA-SVM not only keeps an SVM formulation, but also avoids the computation of matrix inversion. Thus, we can realize its fast version, that is, improved time-adaptive core vector machine (ITA-CVM) for large nonstationary datasets by using the CVM technique. ITA-CVM has the merit of asymptotic linear time complexity for large nonstationary datasets as well as inherits the advantage of TA-SVM. The effectiveness of the proposed classifiers ITA-SVM and ITA-CVM is also experimentally confirmed.
Study on time-frequency analysis method of very fast transient overvoltage
Li, Shuai; Liu, Shiming; Huang, Qiyan; Fu, Chuanshun
2018-04-01
The operation of the disconnector in the gas insulated substation (GIS) may produce very fast transient overvoltage (VFTO), which has the characteristics of short rise time, short duration, high amplitude and rich frequency components. VFTO can cause damage to GIS and secondary equipment, and the frequency components contained in the VFTO can cause resonance overvoltage inside the transformer, so it is necessary to study the spectral characteristics of the VFTO. From the perspective of signal processing, VFTO is a kind of non-stationary signal, the traditional Fourier transform is difficult to describe its frequency which changes with time, so it is necessary to use time-frequency analysis to analyze VFTO spectral characteristics. In this paper, we analyze the performance of short time Fourier transform (STFT), Wigner-Ville distribution (WVD), pseudo Wigner-Ville distribution (PWVD) and smooth pseudo Wigner-Ville distribution (SPWVD). The results show that SPWVD transform is the best. The time-frequency aggregation of SPWVD is higher than STFT, and it does not have cross-interference terms, which can meet the requirements of VFTO spectrum analysis.
Size dependence study of the ordering temperature in the Fast Monte Carlo method
Energy Technology Data Exchange (ETDEWEB)
Velasquez, E. A., E-mail: eavelas@gmail.com [Universidad de San Buenaventura Seccional Medellin, Grupo de Investigacion en Modelamiento y Simulacion Computacional, Facultad de Ingenierias (Colombia); Mazo-Zuluaga, J., E-mail: johanmazo@gmail.com [Universidad de Antioquia, Grupo de Estado Solido, Grupo de Instrumentacion Cientifica y Microelectronica, Instituto de Fisica-FCEN (Colombia); Mejia-Lopez, J., E-mail: jmejia@puc.cl [Universidad de Antioquia, Instituto de Fisica-FCEN (Colombia)
2013-02-15
Based on the framework of the Fast Monte Carlo approach, we study the diameter dependence of the ordering temperature in magnetic nanostructures of cylindrical shape. For the purposes of this study, Fe cylindrical-shaped samples of different sizes (20 nm height, 30-100 nm in diameter) have been chosen, and their magnetic properties have been computed as functions of the scaled temperature. Two main set of results are concluded: (a) the ordering temperature of nanostructures follows a linear scaling relationship as a function of the scaling factor x, for all the studied sizes. This finding rules out a scaling relation T Prime {sub c} = x{sup 3{eta}}T{sub c} (where {eta} is a scaling exponent, and T Prime {sub c} and T{sub c} are the scaled and true ordering temperatures) that has been proposed in the literature, and suggests that temperature should scale linearly with the scaling factor x. (b) For the nanostructures, there are three different order-disorder magnetic transition modes depending on the system's size, in very good agreement with previous experimental reports.
A Fast Time-Delay Calculation Method in Through-Wall-Radar Detection Scenario
Directory of Open Access Journals (Sweden)
Zhang Qi
2016-01-01
Full Text Available In TWR (Through Wall Radar signal processing procedure, time delay estimation is one of the key steps in target localization and high resolution imaging. In time domain imaging procedure such as back projection imaging algorithm, round trip propagation time delay at the path of “transmitter-target-receiver” needs to be calculated for each pixel in imaging region. In typical TWR scenario, transmitter and receiver are at one side and targets at the other side of a wall. Based on two-dimensional searching algorithm or solving two variables equation of four times, traditional time delay calculation algorithms are complex and time consuming, and cannot be used to real-time imaging procedure. In this paper, a new fast time-delay (FTD algorithm is presented. Because of that incident angle at one side equals to refracting angle at the other side, an equation of lateral distance through the wall can be established. By solving this equation, the lateral distance can be obtained and total propagation time delay can be calculated subsequently. Through processing simulation data, the result shows that new algorithm can be applied effectively to real-time time-delay calculation in TWR signal processing.
A fast and accurate method for perturbative resummation of transverse momentum-dependent observables
Kang, Daekyoung; Lee, Christopher; Vaidya, Varun
2018-04-01
We propose a novel strategy for the perturbative resummation of transverse momentum-dependent (TMD) observables, using the q T spectra of gauge bosons ( γ ∗, Higgs) in pp collisions in the regime of low (but perturbative) transverse momentum q T as a specific example. First we introduce a scheme to choose the factorization scale for virtuality in momentum space instead of in impact parameter space, allowing us to avoid integrating over (or cutting off) a Landau pole in the inverse Fourier transform of the latter to the former. The factorization scale for rapidity is still chosen as a function of impact parameter b, but in such a way designed to obtain a Gaussian form (in ln b) for the exponentiated rapidity evolution kernel, guaranteeing convergence of the b integral. We then apply this scheme to obtain the q T spectra for Drell-Yan and Higgs production at NNLL accuracy. In addition, using this scheme we are able to obtain a fast semi-analytic formula for the perturbative resummed cross sections in momentum space: analytic in its dependence on all physical variables at each order of logarithmic accuracy, up to a numerical expansion for the pure mathematical Bessel function in the inverse Fourier transform that needs to be performed just once for all observables and kinematics, to any desired accuracy.
BLESS 2: accurate, memory-efficient and fast error correction method.
Heo, Yun; Ramachandran, Anand; Hwu, Wen-Mei; Ma, Jian; Chen, Deming
2016-08-01
The most important features of error correction tools for sequencing data are accuracy, memory efficiency and fast runtime. The previous version of BLESS was highly memory-efficient and accurate, but it was too slow to handle reads from large genomes. We have developed a new version of BLESS to improve runtime and accuracy while maintaining a small memory usage. The new version, called BLESS 2, has an error correction algorithm that is more accurate than BLESS, and the algorithm has been parallelized using hybrid MPI and OpenMP programming. BLESS 2 was compared with five top-performing tools, and it was found to be the fastest when it was executed on two computing nodes using MPI, with each node containing twelve cores. Also, BLESS 2 showed at least 11% higher gain while retaining the memory efficiency of the previous version for large genomes. Freely available at https://sourceforge.net/projects/bless-ec dchen@illinois.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Improved meta-analytic methods show no effect of chromium supplements on fasting glucose.
Bailey, Christopher H
2014-01-01
The trace mineral chromium has been extensively researched over the years in its role in glucose metabolism. Dietary supplement companies have attempted to make claims that chromium may be able to treat or prevent diabetes. Previous meta-analyses/systematic reviews have indicated that chromium supplementation results in a significant lowering of fasting glucose in diabetics but not in nondiabetics. A meta-analysis was conducted using an alternative measure of effect size, d(ppc2) in order to account for changes in the control group as well as the chromium group. The literature search included MEDLINE, the Cochrane Controlled Trials Register, and previously published article reviews, systematic reviews, and meta-analyses. Included studies were randomized, placebo-controlled trials in the English language with subjects that were nonpregnant adults, both with and without diabetes. Sixteen studies with 809 participants (440 diabetics and 369 nondiabetics) were included in the analysis. Screening for publication bias indicated symmetry of the data. Tests of heterogeneity indicated the use of a fixed-effect model (I² = 0 %). The analysis indicated that there was no significant effect of chromium supplementation in diabetics or nondiabetics, with a weighted average effect size of 0.02 (SE = 0.07), p = 0.787, CI 95 % = -0.12 to 0.16. Chromium supplementation appears to provide no benefits to populations where chromium deficiency is unlikely.
A new Tone's method in APOLLO3® and its application to fast and thermal reactor calculations
Directory of Open Access Journals (Sweden)
Li Mao
2017-09-01
Full Text Available This paper presents a newly developed resonance self-shielding method based on Tone's method in APOLLO3® for fast and thermal reactor calculations. The new method is based on simplified models, the narrow resonance approximation for the slowing down source and Tone's approximation for group collision probability matrix. It utilizes mathematical probability tables as quadrature formulas in calculating effective cross-sections. Numerical results for the ZPPR drawer calculations in 1,968 groups show that, in the case of the double-column fuel drawer, Tone's method gives equivalent precision to the subgroup method while markedly reducing the total number of collision probability matrix calculations and hence the central processing unit time. In the case of a single-column fuel drawer with the presence of a uranium metal material, Tone's method obtains less precise results than those of the subgroup method due to less precise heterogeneous–homogeneous equivalence. The same options are also applied to PWR UOX, MOX, and Gd cells using the SHEM 361-group library, with the objective of analyzing whether this energy mesh might be suitable for the application of this methodology to thermal systems. The numerical results show that comparable precision is reached with both Tone's and the subgroup methods, with the satisfactory representation of intrapellet spatial effects.
Seismic data restoration with a fast L1 norm trust region method
International Nuclear Information System (INIS)
Cao, Jingjie; Wang, Yanfei
2014-01-01
Seismic data restoration is a major strategy to provide reliable wavefield when field data dissatisfy the Shannon sampling theorem. Recovery by sparsity-promoting inversion often get sparse solutions of seismic data in a transformed domains, however, most methods for sparsity-promoting inversion are line-searching methods which are efficient but are inclined to obtain local solutions. Using trust region method which can provide globally convergent solutions is a good choice to overcome this shortcoming. A trust region method for sparse inversion has been proposed, however, the efficiency should be improved to suitable for large-scale computation. In this paper, a new L 1 norm trust region model is proposed for seismic data restoration and a robust gradient projection method for solving the sub-problem is utilized. Numerical results of synthetic and field data demonstrate that the proposed trust region method can get excellent computation speed and is a viable alternative for large-scale computation. (paper)
Koster, Remco A.; Alffenaar, Jan-Willem C.; Greijdanus, Ben; VanDerNagel, Joanneke E. L.; Uges, Donald R. A.
Background: To facilitate the monitoring of drug abuse by patients, a method was developed and validated for fast and highly selective screening for amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylphenidate, cocaine,
International Nuclear Information System (INIS)
Schmid, J.
1985-11-01
A package of updated computer codes for velocity and temperature field calculations for a fast reactor fuel subassembly (or its part) by the finite element method is described. Isoparametric triangular elements of the second degree are used. (author)
Fast optimization of binary clusters using a novel dynamic lattice searching method
International Nuclear Information System (INIS)
Wu, Xia; Cheng, Wen
2014-01-01
Global optimization of binary clusters has been a difficult task despite of much effort and many efficient methods. Directing toward two types of elements (i.e., homotop problem) in binary clusters, two classes of virtual dynamic lattices are constructed and a modified dynamic lattice searching (DLS) method, i.e., binary DLS (BDLS) method, is developed. However, it was found that the BDLS can only be utilized for the optimization of binary clusters with small sizes because homotop problem is hard to be solved without atomic exchange operation. Therefore, the iterated local search (ILS) method is adopted to solve homotop problem and an efficient method based on the BDLS method and ILS, named as BDLS-ILS, is presented for global optimization of binary clusters. In order to assess the efficiency of the proposed method, binary Lennard-Jones clusters with up to 100 atoms are investigated. Results show that the method is proved to be efficient. Furthermore, the BDLS-ILS method is also adopted to study the geometrical structures of (AuPd) 79 clusters with DFT-fit parameters of Gupta potential
International Nuclear Information System (INIS)
2006-03-01
This newsletter makes a monthly synthesis of the European CO 2 market: traded volumes, spot prices, conformability of facilities, supply and demand, climate indexes (temperature, precipitations from March 2005 to February 2006), economic activity indicators (industrial production from December 2004 to December 2005), confidence index of business leaders (from February 2005 to February 2006), changes in energy prices (from March 2005 to February 2006), CO 2 quotas allocated to European Union countries and detailed indicators of CO 2 market, climate, economic activity and energy prices. (J.S.)
Wobbled splatting-a fast perspective volume rendering method for simulation of x-ray images from CT
International Nuclear Information System (INIS)
Birkfellner, Wolfgang; Seemann, Rudolf; Figl, Michael; Hummel, Johann; Ede, Christopher; Homolka, Peter; Yang Xinhui; Niederer, Peter; Bergmann, Helmar
2005-01-01
3D/2D registration, the automatic assignment of a global rigid-body transformation matching the coordinate systems of patient and preoperative volume scan using projection images, is an important topic in image-guided therapy and radiation oncology. A crucial part of most 3D/2D registration algorithms is the fast computation of digitally rendered radiographs (DRRs) to be compared iteratively to radiographs or portal images. Since registration is an iterative process, fast generation of DRRs-which are perspective summed voxel renderings-is desired. In this note, we present a simple and rapid method for generation of DRRs based on splat rendering. As opposed to conventional splatting, antialiasing of the resulting images is not achieved by means of computing a discrete point spread function (a so-called footprint), but by stochastic distortion of either the voxel positions in the volume scan or by the simulation of a focal spot of the x-ray tube with non-zero diameter. Our method generates slightly blurred DRRs suitable for registration purposes at framerates of approximately 10 Hz when rendering volume images with a size of 30 MB. (note)
Li, Meng; Gu, Xian-Ming; Huang, Chengming; Fei, Mingfa; Zhang, Guoyu
2018-04-01
In this paper, a fast linearized conservative finite element method is studied for solving the strongly coupled nonlinear fractional Schrödinger equations. We prove that the scheme preserves both the mass and energy, which are defined by virtue of some recursion relationships. Using the Sobolev inequalities and then employing the mathematical induction, the discrete scheme is proved to be unconditionally convergent in the sense of L2-norm and H α / 2-norm, which means that there are no any constraints on the grid ratios. Then, the prior bound of the discrete solution in L2-norm and L∞-norm are also obtained. Moreover, we propose an iterative algorithm, by which the coefficient matrix is independent of the time level, and thus it leads to Toeplitz-like linear systems that can be efficiently solved by Krylov subspace solvers with circulant preconditioners. This method can reduce the memory requirement of the proposed linearized finite element scheme from O (M2) to O (M) and the computational complexity from O (M3) to O (Mlog M) in each iterative step, where M is the number of grid nodes. Finally, numerical results are carried out to verify the correction of the theoretical analysis, simulate the collision of two solitary waves, and show the utility of the fast numerical solution techniques.
Goto, N
1987-09-01
This paper describes a new series of staining methods which can discriminatively demonstrate every structure of the nervous system, including axons and capillaries, in animal and human materials. Methods described in this paper consist of one primary stain, luxol fast blue-periodic acid Schiff-hematoxylin (LPH) and six different subsidiary staining methods. The LPH triple stain can precisely differentiate the following structures: neurons (Nissl bodies, cytoplasm, nuclear membrane and nucleolus), various kinds of nuclei (glia, ependyma, endothelium, leucocyte, connective tissue, etc.), myelin sheaths, neuronal processes (axons and dendrites), reacted glial cell bodies (protoplasmic astrocytes, foamy cells, etc.), blood vessels (arteries, veins and capillaries), meninges, intervening connective tissue, erythrocytes, lipofuscin granules, amyloid bodies, and others. Subsidiary staining methods are also described briefly. Applications are discussed in the context of staining technology and neuromorphological research.
A Fast and Accurate UPLC Method for Analysis of Proteinogenic Amino Acids
Meussen, B.J.; Zeeland, van A.N.T.; Bruins, M.E.; Sanders, J.P.M.
2014-01-01
A reliable and inexpensive method for the measurement of proteinogenic amino acids was developed. It allows the screening of large sample volumes that is important for current food and feed applications, but also for future biobased applications. The method is based on acid hydrolysis and automated
A Practical, Robust and Fast Method for Location Localization in Range-Based Systems.
Huang, Shiping; Wu, Zhifeng; Misra, Anil
2017-12-11
Location localization technology is used in a number of industrial and civil applications. Real time location localization accuracy is highly dependent on the quality of the distance measurements and efficiency of solving the localization equations. In this paper, we provide a novel approach to solve the nonlinear localization equations efficiently and simultaneously eliminate the bad measurement data in range-based systems. A geometric intersection model was developed to narrow the target search area, where Newton's Method and the Direct Search Method are used to search for the unknown position. Not only does the geometric intersection model offer a small bounded search domain for Newton's Method and the Direct Search Method, but also it can self-correct bad measurement data. The Direct Search Method is useful for the coarse localization or small target search domain, while the Newton's Method can be used for accurate localization. For accurate localization, by utilizing the proposed Modified Newton's Method (MNM), challenges of avoiding the local extrema, singularities, and initial value choice are addressed. The applicability and robustness of the developed method has been demonstrated by experiments with an indoor system.
Fast, versatile x-ray fluorescence method for measuring tin in impregnated wood
DEFF Research Database (Denmark)
Drabæk, I.; Christensen, Leif Højslet
1985-01-01
The present paper describes an energy-dispersive x-ray fluorescence method for measuring tin in bis(tri-n-butyl)tin-oxide impregnated wood. The proposed method is of the backscatter/fundamental parameter type. Its versatility, precision, and accuracy is demonstrated by analyses of eleven samples...
A fast exact simulation method for a class of Markov jump processes.
Li, Yao; Hu, Lili
2015-11-14
A new method of the stochastic simulation algorithm (SSA), named the Hashing-Leaping method (HLM), for exact simulations of a class of Markov jump processes, is presented in this paper. The HLM has a conditional constant computational cost per event, which is independent of the number of exponential clocks in the Markov process. The main idea of the HLM is to repeatedly implement a hash-table-like bucket sort algorithm for all times of occurrence covered by a time step with length τ. This paper serves as an introduction to this new SSA method. We introduce the method, demonstrate its implementation, analyze its properties, and compare its performance with three other commonly used SSA methods in four examples. Our performance tests and CPU operation statistics show certain advantages of the HLM for large scale problems.