RANS Simulation of the Heave Response of a Two-Body Floating Point Wave Absorber: Preprint
Energy Technology Data Exchange (ETDEWEB)
Yu, Y.; Li, Y.
2011-03-01
A preliminary study on a two-body floating wave absorbers is presented in this paper. A Reynolds-Averaged Navier-Stokes computational method is applied for analyzing the hydrodynamic heave response of the absorber in operational wave conditions. The two-body floating wave absorber contains a float section and a submerged reaction section. For validation purposes, our model is first assumed to be locked. The two sections are forced to move together with each other. The locked single body model is used in a heave decay test, where the RANS result is validated with the experimental measurement. For the two-body floating point absorber simulation, the two sections are connected through a mass-spring-damper system, which is applied to simulate the power take-off mechanism under design wave conditions. Overall, the details of the flow around the absorber and its nonlinear interaction with waves are investigated, and the power absorption efficiency of the two-body floating wave absorber in waves with a constant value spring-damper system is examined.
Parametric Study of Two-Body Floating-Point Wave Absorber
Institute of Scientific and Technical Information of China (English)
Atena Amiri; Roozbeh Panahi; Soheil Radfar
2016-01-01
In this paper, we present a comprehensive numerical simulation of a point wave absorber in deep water. Analyses are performed in both the frequency and time domains. The converter is a two-body floating-point absorber (FPA) with one degree of freedom in the heave direction. Its two parts are connected by a linear mass-spring-damper system. The commercial ANSYS-AQWA software used in this study performs well in considering validations. The velocity potential is obtained by assuming incompressible and irrotational flow. As such, we investigated the effects of wave characteristics on energy conversion and device efficiency, including wave height and wave period, as well as the device diameter, draft, geometry, and damping coefficient. To validate the model, we compared our numerical results with those from similar experiments. Our study results can clearly help to maximize the converter’s efficiency when considering specific conditions.
Serial floating point formatter
Energy Technology Data Exchange (ETDEWEB)
Peterson, R. D.; Penner, W. A.
1985-11-12
A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.
Floating point coprocessor upgrade
Energy Technology Data Exchange (ETDEWEB)
Weber, T.
1987-04-01
A method was developed to increase the throughput of the Hewlett Packard, 98635A floating point processor equipped, model 236C computer. The increase was carried out in three phases each with a clock and or chip change during the modification. Two programs were written to test the results and evaluate the increases in performance made to the computer. The first one shows reduction in processing times of 34.3%, while the other recorded 34.6%.
Collapsing floating-point operations
Defour, David
2004-01-01
This paper addresses the issue of collapsing dependent floating-point operations. The presentation focuses on studying the dataflow graph of benchmark involving a large number of floating-point instructions. In particular, it focuses on the relevance of new floating-point operators performing two dependent operations which are similar to "fused multiply and add". Finally, this paper examines the implementation cost and critical path reduction from this strategy.
FLOPAK: FLOATING POINT PROGRAMING PACKAGE,
FLOPAK is a Packard-Bell 250 Computer semi-automatic, floating - point programing system which may be operated simultaneously in either of two modes...250 floating - point system available which may be used in real-time control. The system was originally designed to solve a real-time communication problem....The first is a non-time optimized mode which may be used by inex perienced coders; the second mode is a high-speed, fully time-optimized floating
NULL Convention Floating Point Multiplier
Directory of Open Access Journals (Sweden)
Anitha Juliette Albert
2015-01-01
Full Text Available Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.
NULL convention floating point multiplier.
Albert, Anitha Juliette; Ramachandran, Seshasayanan
2015-01-01
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to perform floating point multiplication. The proposed multiplier offers substantial decrease in power consumption when compared with its synchronous version. Performance attributes of the NULL convention logic floating point multiplier, obtained from Xilinx simulation and Cadence, are compared with its equivalent synchronous implementation.
NULL Convention Floating Point Multiplier
Anitha Juliette Albert; Seshasayanan Ramachandran
2015-01-01
Floating point multiplication is a critical part in high dynamic range and computational intensive digital signal processing applications which require high precision and low power. This paper presents the design of an IEEE 754 single precision floating point multiplier using asynchronous NULL convention logic paradigm. Rounding has not been implemented to suit high precision applications. The novelty of the research is that it is the first ever NULL convention logic multiplier, designed to p...
A CMOS floating point multiplier
Uya, M.; Kaneko, K.; Yasui, J.
1984-10-01
This paper describes a 32-bit CMOS floating point multiplier. The chip can perform 32-bit floating point multiplication (based on the proposed IEEE Standard format) and 24-bit fixed point multiplication (two's complement format) in less than 78.7 and 71.1 ns, respectively, and the typical power dissipation is 195 mW at 10 million operations per second. High-speed multiplication techniques - a modified Booth's allgorithm, a carry save adder scheme, a high-speed CMOS full adder, and a modified carry select adder - are used to achieve the above high performance. The chip is designed for compatibility with 16-bit microcomputer systems, and is fabricated in 2 micron n-well CMOS technology; it contains about 23000 transistors of 5.75 x 5.67 sq mm in size.
Floating point numbers are real numbers
Mascarenhas, Walter F.
2016-01-01
Floating point arithmetic allows us to use a finite machine, the digital computer, to reach conclusions about models based on continuous mathematics. In this article we work in the other direction, that is, we present examples in which continuous mathematics leads to sharp, simple and new results about the evaluation of sums, square roots and dot products in floating point arithmetic.
Towards sensible floating-point arithmetic
Energy Technology Data Exchange (ETDEWEB)
Cody, W.J.
1980-01-01
Efforts to promote the development of high-quality transportable numerical software show that few, if any, of the floating-point arithmetic systems in existing computers are completely satisfactory for serious numerical computation. Examination of the defects in these systems leads to specifications for a sensible floating-point system from a numerical analyst's viewpoint. 1 table.
Floating-point standards: Theory and practice
Energy Technology Data Exchange (ETDEWEB)
Cody, W.J.
1987-01-01
ANSI/IEEE Std 754-1985, the IEEE Standard for Binary Floating-Point Arithmetic, has now been joined by IEEE Std 854-1987, A Radix- Independent Standard for Floating-Point Arithmetic. These standards specify floating-point arithmetic systems that are intended to simplify the preparation of high-quality numerical software. The success of these standards hinges on how well they are implemented and how well they are supported by enhancements to algebraic languages. This paper briefly outlines the arithmetic systems specified by the standards, and discusses some existing implementations. 16 refs., 1 tab.
Floating point arithmetic in future supercomputers
Bailey, David H.; Barton, John T.; Simon, Horst D.; Fouts, Martin J.
1989-01-01
Considerations in the floating-point design of a supercomputer are discussed. Particular attention is given to word size, hardware support for extended precision, format, and accuracy characteristics. These issues are discussed from the perspective of the Numerical Aerodynamic Simulation Systems Division at NASA Ames. The features believed to be most important for a future supercomputer floating-point design include: (1) a 64-bit IEEE floating-point format with 11 exponent bits, 52 mantissa bits, and one sign bit and (2) hardware support for reasonably fast double-precision arithmetic.
Multiprocessing system for performing floating point arithmetic operations
Energy Technology Data Exchange (ETDEWEB)
Nguyenphu, M.; Thatcher, L.E.
1990-10-02
This patent describes a data processing system. It comprises: a fixed point arithmetic processor means for performing fixed point arithmetic operations and including control means for decoding a floating point arithmetic instruction specifying a floating point arithmetic operation, and an addressing means for computing addresses for floating point data for the floating point operation from a memory means. The memory means for storing data and including means for receiving the addresses from the fixed point arithmetic processor means and providing the floating point data to a floating point arithmetic processor means; and the floating point arithmetic processor means for performing floating point arithmetic operations and including control means for decoding the floating point instruction and performing the specified floating point arithmetic operation upon the floating point data from the memory means.
Genetic Algorithms, Floating Point Numbers and Applications
Hardy, Yorick; Steeb, Willi-Hans; Stoop, Ruedi
The core in most genetic algorithms is the bitwise manipulations of bit strings. We show that one can directly manipulate the bits in floating point numbers. This means the main bitwise operations in genetic algorithm mutations and crossings are directly done inside the floating point number. Thus the interval under consideration does not need to be known in advance. For applications, we consider the roots of polynomials and finding solutions of linear equations.
Verified Compilation of Floating-Point Computations
Boldo, Sylvie; Jourdan, Jacques-Henri; Leroy, Xavier; Melquiond, Guillaume
2015-01-01
International audience; Floating-point arithmetic is known to be tricky: roundings, formats, exceptional values. The IEEE-754 standard was a push towards straightening the field and made formal reasoning about floating-point computations easier and flourishing. Unfortunately, this is not sufficient to guarantee the final result of a program, as several other actors are involved: programming language, compiler, architecture. The CompCert formally-verified compiler provides a solution to this p...
Dynamically Reconfigurable Processor for Floating Point Arithmetic
Directory of Open Access Journals (Sweden)
S. Anbumani,
2014-01-01
Full Text Available Recently, development of embedded processors is toward miniaturization and energy saving for ecology. On the other hand, high performance arithmetic circuits are required in a lot of application in science and technology. Dynamically reconfigurable processors have been developed to meet these requests. They can change circuit configuration according to instructions in program instantly during operations.This paper describes, a dynamically reconfigurable circuit for floating-point arithmetic is proposed. The arithmetic circuit consists of two single precision floating-point arithmetic circuits. It performs double precision floating-point arithmetic by reconfiguration. Dynamic reconfiguration changes circuit construction at one clock cycle during operation without stopping circuits. It enables reconfiguration of circuits in a few nano seconds. The proposed circuit is reconfigured in two modes. In first mode it performs one double precision floating-point arithmetic or else the circuit will perform two parallel operations of single precision floating-point arithmetic. The new system design reduces implementation area by reconfiguring common parts of each operation. It also increases the processing speed with a very little number of clocks.
Block floating point for radar data
DEFF Research Database (Denmark)
Christensen, Erik Lintz
1999-01-01
Integer, floating point, and block floating point (BFP) data formats are analyzed and compared in order to establish the mathematical tools for selection of an optimal format which fulfils the demands of high resolution radar (SAR) data to large dynamic range and adequate S/N. The analysis takes...... quantization noise and saturation distortion into account and concludes that it is preferred to use small blocks and a (new) modified BFP format applying fractional exponents. Data from the EMISAR radar system are applied to illustrate the merits of the different schemes....
PLM floating-point interface program
Energy Technology Data Exchange (ETDEWEB)
Paoni, C.; Maples, M.
1976-03-03
A major failing of Intel's PLM language is its inability to handle scientific notation (floating-point) calculations. An interface program that allows PLM to perform such calculations is described. A comparison of this modified PLM with an assembly language program has shown PLM's effectiveness in reducing the cost of a project. (auth)
Improvements in floating point addition/subtraction operations
Energy Technology Data Exchange (ETDEWEB)
Farmwald, P.M.
1984-02-24
Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.
New fixed points of the renormalisation group for two-body scattering
Energy Technology Data Exchange (ETDEWEB)
Birse, M.C. [The University of Manchester, Theoretical Physics Division, School of Physics and Astronomy, Manchester (United Kingdom); Epelbaum, E. [Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik II, Fakultaet fuer Physik und Astronomie, Bochum (Germany); Gegelia, J. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich (Germany); Tbilisi State University, Tbilisi (Georgia)
2016-02-15
We outline a separable matrix ansatz for the potentials in effective field theories of non-relativistic two-body systems with short-range interactions. We use this ansatz to construct new fixed points of the renormalisation-group equation for these potentials. New fixed points indicate a much richer structure than previously recognized in the RG flows of simple short-range potentials. (orig.)
A multiple floating point coprocessor architecture
Energy Technology Data Exchange (ETDEWEB)
Rauchwerger, L.; Farmwald, M.P. (Center for Supercomputing Research and Development, Univ. of Illinois at Urbana-Champaign, 305 Talbot Lab., Urbana, IL (US))
1990-06-01
General purpose microprocessor based computers usually speed their arithmetic processing performance by using a floating point co-processor. Because adding more co-processors represents neither a technological nor a cost problem the authors investigated a system based on a MIPS R2000 (2) and 4 floating point units. In this paper they show a block diagram of such an implementation and how two important scientific operations can be accelerated using a single unmodified data bus. A large percentage of the engineering applications are solved with the help of linear algebra methods like BLAS3 (4) algorithms; it is precisely for these primitives that the proposed architecture brings significant performance gains. The first operation described is a matrix multiplication algorithm, its timing diagram and some results. Next a polynomial evaluation technique is examined. The authors show how to use the same ideas with various other microprocessors.
Optimizing polynomials for floating-point implementation
De Dinechin, Florent
2008-01-01
The floating-point implementation of a function on an interval often reduces to polynomial approximation, the polynomial being typically provided by Remez algorithm. However, the floating-point evaluation of a Remez polynomial sometimes leads to catastrophic cancellations. This happens when some of the polynomial coefficients are very small in magnitude with respects to others. In this case, it is better to force these coefficients to zero, which also reduces the operation count. This technique, classically used for odd or even functions, may be generalized to a much larger class of functions. An algorithm is presented that forces to zero the smaller coefficients of the initial polynomial thanks to a modified Remez algorithm targeting an incomplete monomial basis. One advantage of this technique is that it is purely numerical, the function being used as a numerical black box. This algorithm is implemented within a larger polynomial implementation tool that is demonstrated on a range of examples, resulting in ...
Synthesizing Accurate Floating-Point Formulas
Ioualalen, Arnault; Martel, Matthieu
2013-01-01
International audience; Many critical embedded systems perform floating-point computations yet their accuracy is difficult to assert and strongly depends on how formulas are written in programs. In this article, we focus on the synthesis of accurate formulas mathematically equal to the original formulas occurring in source codes. In general, an expression may be rewritten in many ways. To avoid any combinatorial explosion, we use an intermediate representation, called APEG, enabling us to rep...
Implementation of Floating-point Coprocessor
Skogstrøm, Kristian
2005-01-01
This thesis presents the architecture and implementation of a high-performance floating-point coprocessor for Atmel's new microcontroller. The coprocessor architecture is based on a fused multiply-add pipeline developed in the specialization project, TDT4720. This pipeline has been optimized significantly and extended to support negation of all operands and single-precision input and output. New hardware has been designed for the decode/fetch unit, the register file, the compare/convert pipe...
Termination of floating-point computations
Serebrenik, Alexander; De Schreye, Danny
2005-01-01
Numerical computations form an essential part of almost any real-world program. Traditional approaches to termination of logic programs are restricted to domains isomorphic to (N,>); more recent works study termination of integer computations where the lack of well-foundedness of the integers has to be taken into account. Termination of computations involving floating-point numbers can be counterintuitive because of rounding errors and implementation conventions. We present a novel technique ...
Arithmetic Operations Beyond Floating Point Number Precision
Wang, Chih-Yueh; Chen, Hong-Yu; Chen, Yung-Ko
2010-01-01
In basic computational physics classes, students often raise the question of how to compute a number that exceeds the numerical limit of the machine. While technique of avoiding overflow/underflow has practical application in the electrical and electronics engineering industries, it is not commonly utilized in scientific computing, because scientific notation is adequate in most cases. We present an undergraduate project that deals with such calculations beyond a machine's numerical limit, known as arbitrary precision arithmetic. The assignment asks students to investigate the validity of floating point number precision and the approach of calculating the exact value of a large number, using the basic scientific programming language Fortran. Examples of the successive multiplication of even number and the multiplication and division of two overflowing floats are presented. The application of the scheme to hardware and firmware design which requires the allocation of finite memory, as in a digital signal proce...
An integrated circuit floating point accumulator
Goldsmith, T. C.
1977-01-01
Goddard Space Flight Center has developed a large scale integrated circuit (type 623) which can perform pulse counting, storage, floating point compression, and serial transmission, using a single monolithic device. Counts of 27 or 19 bits can be converted to transmitted values of 12 or 8 bits respectively. Use of the 623 has resulted in substantial savaings in weight, volume, and dollar resources on at least 11 scientific instruments to be flown on 4 NASA spacecraft. The design, construction, and application of the 623 are described.
Rounding in redundant digit floating point system
Fahmy, Hossam A. H.; Flynn, Michael J.
2003-12-01
Redundant representations are used to increase the performance of arithmetic units. If redundancy is eliminated, the bits needed to represent a number may increase or decrease depending on the type of redundancy used. In such a redundant representation, finding the exact location and correct decision for rounding without eliminating the redundancy or loosing its performance gains is difficult. This paper discusses the different issues related to rounding in redundant systems. It also presents a solution that was used to maintain the gains of redundancy in a floating point unit while correctly implementing the IEEE rounding modes.
Trident: An FPGA Compiler Framework for Floating-Point Algorithms.
Energy Technology Data Exchange (ETDEWEB)
Tripp J. L. (Justin L.); Peterson, K. D. (Kristopher D.); Poznanovic, J. D. (Jeffrey Daniel); Ahrens, C. M. (Christine Marie); Gokhale, M. (Maya)
2005-01-01
Trident is a compiler for floating point algorithms written in C, producing circuits in reconfigurable logic that exploit the parallelism available in the input description. Trident automatically extracts parallelism and pipelines loop bodies using conventional compiler optimizations and scheduling techniques. Trident also provides an open framework for experimentation, analysis, and optimization of floating point algorithms on FPGAs and the flexibility to easily integrate custom floating point libraries.
Implementing decimal floating-point arithmetic through binary: some suggestions
Brisebarre, Nicolas; Ercegovac, Milos; Louvet, Nicolas; Martin-Dorel, Erik; Muller, Jean-Michel; Panhaleux, Adrien
2010-01-01
International audience; We propose several algorithms and provide some related results that make it possible to implement decimal floating-point arithmetic on a processor that does not have decimal operators, using the available binary floating-point functions. In this preliminary study, we focus on round-to-nearest mode only. We show that several functions in decimal32 and decimal64 arithmetic can be implemented using binary64 and binary128 floating-point arithmetic, respectively. Specifical...
FPGA Based Quadruple Precision Floating Point Arithmetic for Scientific Computations
Directory of Open Access Journals (Sweden)
Mamidi Nagaraju
2012-09-01
Full Text Available In this project we explore the capability and flexibility of FPGA solutions in a sense to accelerate scientific computing applications which require very high precision arithmetic, based on IEEE 754 standard 128-bit floating-point number representations. Field Programmable Gate Arrays (FPGA is increasingly being used to design high end computationally intense microprocessors capable of handling floating point mathematical operations. Quadruple Precision Floating-Point Arithmetic is important in computational fluid dynamics and physical modelling, which require accurate numerical computations. However, modern computers perform binary arithmetic, which has flaws in representing and rounding the numbers. As the demand for quadruple precision floating point arithmetic is predicted to grow, the IEEE 754 Standard for Floating-Point Arithmetic includes specifications for quadruple precision floating point arithmetic. We implement quadruple precision floating point arithmetic unit for all the common operations, i.e. addition, subtraction, multiplication and division. While previous work has considered circuits for low precision floating-point formats, we consider the implementation of 128-bit quadruple precision circuits. The project will provide arithmetic operation, simulation result, hardware design, Input via PS/2 Keyboard interface and results displayed on LCD using Xilinx virtex5 (XC5VLX110TFF1136 FPGA device.
Certifying floating-point implementations using Gappa
De Dinechin, Florent; Melquiond, Guillaume
2008-01-01
High confidence in floating-point programs requires proving numerical properties of final and intermediate values. One may need to guarantee that a value stays within some range, or that the error relative to some ideal value is well bounded. Such work may require several lines of proof for each line of code, and will usually be broken by the smallest change to the code (e.g. for maintenance or optimization purpose). Certifying these programs by hand is therefore very tedious and error-prone. This article discusses the use of the Gappa proof assistant in this context. Gappa has two main advantages over previous approaches: Its input format is very close to the actual C code to validate, and it automates error evaluation and propagation using interval arithmetic. Besides, it can be used to incrementally prove complex mathematical properties pertaining to the C code. Yet it does not require any specific knowledge about automatic theorem proving, and thus is accessible to a wide community. Moreover, Gappa may ge...
Open source high performance floating-point modules.
Energy Technology Data Exchange (ETDEWEB)
Underwood, Keith Douglas
2006-02-01
Given the logic density of modern FPGAs, it is feasible to use FPGAs for floating-point applications. However, it is important that any floating-point units that are used be highly optimized. This paper introduces an open source library of highly optimized floating-point units for Xilinx FPGAs. The units are fully IEEE compliant and achieve approximately 230 MHz operation frequency for double-precision add and multiply in a Xilinx Virtex-2-Pro FPGA (-7 speed grade). This speed is achieved with a 10 stage adder pipeline and a 12 stage multiplier pipeline. The area requirement is 571 slices for the adder and 905 slices for the multiplier.
Efficient Implementation of Decimal Floating Point Adder in FPGA
Directory of Open Access Journals (Sweden)
Yang Huijing
2013-10-01
Full Text Available Decimal floating Point adder is one of the most frequent operations used by many financial, business and user-oriented applications but current implementations in FPGAs are very inefficient in terms of both area and latency when compared to binary floating point adder. This paper has shown an efficient implementation of a new parallel decimal floating point module on a reconfigurable platform, which is both area as well as performance optimal. The decimal floating-point Adder was further pipelined into five stages to increase the maximum frequency of operation. The synthesis results for a Stratix IV device indicate that our implementations have 25.1% reduction of the latency and 1.1% reduction of area compared to an existing alter-core adder design, presenting area and delay figures close to those of optimal binary adder trees.
Parametric time delay modeling for floating point units
Fahmy, Hossam A. H.; Liddicoat, Albert A.; Flynn, Michael J.
2002-12-01
A parametric time delay model to compare floating point unit implementations is proposed. This model is used to compare a previously proposed floating point adder using a redundant number representation with other high-performance implementations. The operand width, the fan-in of the logic gates and the radix of the redundant format are used as parameters to the model. The comparison is done over a range of operand widths, fan-in and radices to show the merits of each implementation.
Floating-point multiple data stream digital signal processor
Energy Technology Data Exchange (ETDEWEB)
Fortier, M.; Corinthios, M.J.
1982-01-01
A microprogrammed multiple data stream digital signal processor is introduced. This floating-point processor is capable of implementing optimum Wiener filtering of signals, in general, and images in particular. Generalised spectral analysis transforms such as Fourier, Walsh, Hadamard, and generalised Walsh are efficiently implemented in a bit-slice microprocessor-based architecture. In this architecture, a microprogrammed sequencing section directly controls a central floating-point signal processing unit. Throughout, computations are performed on pipelined multiple complex data streams. 12 references.
Design of a reversible single precision floating point subtractor
Anantha Lakshmi, AV; Sudha, GF
2014-01-01
In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-point operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-point addition/subtraction to ...
Design of a reversible single precision floating point subtractor.
Anantha Lakshmi, Av; Sudha, Gf
2014-01-04
In recent years, Reversible logic has emerged as a major area of research due to its ability to reduce the power dissipation which is the main requirement in the low power digital circuit design. It has wide applications like low power CMOS design, Nano-technology, Digital signal processing, Communication, DNA computing and Optical computing. Floating-point operations are needed very frequently in nearly all computing disciplines, and studies have shown floating-point addition/subtraction to be the most used floating-point operation. However, few designs exist on efficient reversible BCD subtractors but no work on reversible floating point subtractor. In this paper, it is proposed to present an efficient reversible single precision floating-point subtractor. The proposed design requires reversible designs of an 8-bit and a 24-bit comparator unit, an 8-bit and a 24-bit subtractor, and a normalization unit. For normalization, a 24-bit Reversible Leading Zero Detector and a 24-bit reversible shift register is implemented to shift the mantissas. To realize a reversible 1-bit comparator, in this paper, two new 3x3 reversible gates are proposed The proposed reversible 1-bit comparator is better and optimized in terms of the number of reversible gates used, the number of transistor count and the number of garbage outputs. The proposed work is analysed in terms of number of reversible gates, garbage outputs, constant inputs and quantum costs. Using these modules, an efficient design of a reversible single precision floating point subtractor is proposed. Proposed circuits have been simulated using Modelsim and synthesized using Xilinx Virtex5vlx30tff665-3. The total on-chip power consumed by the proposed 32-bit reversible floating point subtractor is 0.410 W.
The Unified Floating Point Vector Coprocessor for Reconfigurable Hardware
Kathiara, Jainik
There has been an increased interest recently in using embedded cores on FPGAs. Many of the applications that make use of these cores have floating point operations. Due to the complexity and expense of floating point hardware, these algorithms are usually converted to fixed point operations or implemented using floating-point emulation in software. As the technology advances, more and more homogeneous computational resources and fixed function embedded blocks are added to FPGAs and hence implementation of floating point hardware becomes a feasible option. In this research we have implemented a high performance, autonomous floating point vector Coprocessor (FPVC) that works independently within an embedded processor system. We have presented a unified approach to vector and scalar computation, using a single register file for both scalar operands and vector elements. The Hybrid vector/SIMD computational model of FPVC results in greater overall performance for most applications along with improved peak performance compared to other approaches. By parameterizing vector length and the number of vector lanes, we can design an application specific FPVC and take optimal advantage of the FPGA fabric. For this research we have also initiated designing a software library for various computational kernels, each of which adapts FPVC's configuration and provide maximal performance. The kernels implemented are from the area of linear algebra and include matrix multiplication and QR and Cholesky decomposition. We have demonstrated the operation of FPVC on a Xilinx Virtex 5 using the embedded PowerPC.
Control implementation for the SPUR floating point coprocessor
Energy Technology Data Exchange (ETDEWEB)
Jensen, D.
1987-01-01
SPUR is a RISC-based multiprocessor workstation being designed to facilitate parallel-processing research. Typically, RISC architectures achieve low performance levels for floating-point intensive applications, as the multiple-cycle floating-point instructions are not implemented in the hardware. In an attempt to raise these performance levels, the SPUR system provides floating-point support through an extended instruction set and tightly-coupled floating-point coprocessor. This report documents the implementation of the control unit for this floating-point coprocessor; describing the coprocessor interface, control PLA definitions, the finite state machine, the dynamic cycle counter, the 4-stage load-store pipeline, and the random logic generated to drive the datapath modules. Implementation techniques and trade-offs are discussed; including design strategy, area and speed optimization, noise margin considerations, and delay balancing rf the datapath control signals for clock skew minimization. Finally, in an attempt to raise these performance levels, the SPUR system The chip is implemented in 2-layer-metal 2..mu..m CMOS technology, and uses a four-phase non-overlapping clock with a target cycle time of approximately 100ns - 140 ns.
A Fast Floating Point Double Precision Implementation on Fpga
Directory of Open Access Journals (Sweden)
Monika Maan
2016-06-01
Full Text Available In the modern day digital systems, floating point units are an important component in many signal and image processing applications. Many approaches of the floating point units have been proposed and compared with their counterparts in recent years. IEEE 754 floating point standard allows two types of precision units for floating point operations, single and double. In the proposed architecture double precision floating point unit is used and basic arithmetic operations are performed. A parallel architecture is proposed along with the high speed adder, which is shared among other operations and can perform operations independently as a separate unit. To improve the area efficiency of the unit, carry select adder is designed with the novel resource sharing technique which allows performing the operations with the minimum usage of the resources while computing the carry and sum for „0‟ and „1‟. The design is implemented using the Xilinx Spartan 6 FPGA and the results show the 23% improvement in the speed of the designed circuit.
Floating point hardware emulator for RSX-11D
Energy Technology Data Exchange (ETDEWEB)
Kellogg, M.; Long, M.
1977-01-01
An RSX-11D task was written to simulate the FP-11 floating point hardware on systems that lack this hardware. The simulation is transparent to tasks using floating point instructions. All normal features of the hardware are simulated exactly, including its action on exception conditions. The emulator is a privileged task occupying about 2.7K words of memory. When it is loaded and run, it sets up a linkage to intercept the reserved instruction trap before it reaches the executive, and route it to a service routine that can decode and simulate the floating point instruction set. The results of a benchmark timing test are given, as are notes on converting the emulator to run under RSX-11M. 1 figure, 2 tables.
VLSI design techniques for floating-point computation
Energy Technology Data Exchange (ETDEWEB)
Bose, B. K.
1988-01-01
The thesis presents design techniques for floating-point computation in VLSI. A basis for area-time design decisions for arithmetic and memory operations is formulated from a study of computationally intensive programs. Tradeoffs in the design and implementation of an efficient coprocessor interface are studied, together with the implications of hardware support for the IEEE Floating-Point Standard. Algorithm area-time tradeoffs for basic arithmetic functions are analyzed in light of changing technology. Details of a single-chip floating-point unit designed in two-micron CMOS for SPUR are described, including special design considerations for very wide data paths. The pervasive effects of scaling technology on different levels of design are explored, from devices and circuits, through logic and micro-architecture, to algorithms and systems.
Floating point representations in quantum circuit synthesis
Wiebe, Nathan; Kliuchnikov, Vadym
2013-09-01
We provide a non-deterministic quantum protocol that approximates the single qubit rotations Rx(2ϕ21ϕ22) using Rx(2ϕ1) and Rx(2ϕ2) and a constant number of Clifford and T operations. We then use this method to construct a ‘floating point’ implementation of a small rotation wherein we use the aforementioned method to construct the exponent part of the rotation and also to combine it with a mantissa. This causes the cost of the synthesis to depend more strongly on the relative (rather than absolute) precision required. We analyze the mean and variance of the T-count required to use our techniques and provide new lower bounds for the T-count for ancilla free synthesis of small single-qubit axial rotations. We further show that our techniques can use ancillas to beat these lower bounds with high probability. We also discuss the T-depth of our method and see that the vast majority of the cost of the resultant circuits can be shifted to parallel computation paths.
Efficient Hybrid Method for Binary Floating Point Multiplication
Directory of Open Access Journals (Sweden)
S. Praveenkumar Reddy,
2014-04-01
Full Text Available This paper presents a high speed binary floating point multiplier based on Hybrid Method. To improve speed multiplication of mantissa is done using Hybrid method replacing existing multipliers like Carry Save Multiplier, Dadda Multiplier and Modified Booth Multiplier. Hybrid method is a combination of Dadda Multiplier and Modified Radix-8 Booth Multiplier. The design achieves high speed with maximum frequency of 555 MHz compared to existing floating point multipliers. The multiplier implemented in Verilog HDL and analyzed in Quartus II 10.0 version. Hybrid Multiplier is compared with existing multipliers.
Floating-to-Fixed-Point Conversion for Digital Signal Processors
Directory of Open Access Journals (Sweden)
Menard Daniel
2006-01-01
Full Text Available Digital signal processing applications are specified with floating-point data types but they are usually implemented in embedded systems with fixed-point arithmetic to minimise cost and power consumption. Thus, methodologies which establish automatically the fixed-point specification are required to reduce the application time-to-market. In this paper, a new methodology for the floating-to-fixed point conversion is proposed for software implementations. The aim of our approach is to determine the fixed-point specification which minimises the code execution time for a given accuracy constraint. Compared to previous methodologies, our approach takes into account the DSP architecture to optimise the fixed-point formats and the floating-to-fixed-point conversion process is coupled with the code generation process. The fixed-point data types and the position of the scaling operations are optimised to reduce the code execution time. To evaluate the fixed-point computation accuracy, an analytical approach is used to reduce the optimisation time compared to the existing methods based on simulation. The methodology stages are described and several experiment results are presented to underline the efficiency of this approach.
High speed matrix processors using floating point representation
Energy Technology Data Exchange (ETDEWEB)
Birkner, D.A.
1980-01-01
The author describes the architecture of a high-speed matrix processor which uses a floating-point format for data representation. It is shown how multipliers and other LSI devices are used in the design to obtain the high speed of the processor.
Block floating-point notation for signal processes
Energy Technology Data Exchange (ETDEWEB)
Simpson, J.E.
1981-03-01
The development and application of a notation for use with block floating-point (BFP) mathematical operations in real-time signal processes is described. The notation has been extensively used in developing perimeter security signal processors such as the Magnetic Intrusion Line Sensor (MILES) Adaptive Digital Processor (MADP) and its forerunner, the Signal Processing Development Unit (SSPDU).
Benchmarks to supplant export FPDR (Floating Point Data Rate) calculations
Energy Technology Data Exchange (ETDEWEB)
Bailey, D.; Brooks, E.; Dongarra, J.; Hayes, A.; Lyon, G.
1988-06-01
Because modern computer architectures render application of the FPDR (Floating Point Data Processing Rate) increasingly difficult, there has been increased interest in export evaluation via actual system performances. The report discusses benchmarking of uniprocessor (usually vector) machines for scientific computation (SIMD array processors are not included), and parallel processing and its characterization for export control.
An Asynchronous IEEE Floating-Point Arithmetic Unit
Directory of Open Access Journals (Sweden)
Joel R. Noche
2007-12-01
Full Text Available An asynchronous floating-point arithmetic unit is designed and tested at the transistor level usingCadence software. It uses CMOS (complementary metal oxide semiconductor and DCVS (differentialcascode voltage switch logic in a 0.35 µm process using a 3.3 V supply voltage, with dual-rail data andsingle-rail control signals using four-phase handshaking.Using 17,085 transistors, the unit handles single-precision (32-bit addition/subtraction, multiplication,division, and remainder using the IEEE 754-1985 Standard for Binary Floating-Point Arithmetic, withrounding and other operations to be handled by separate hardware or software. Division and remainderare done using a restoring subtractive algorithm; multiplication uses an additive algorithm. Exceptionsare noted by flags (and not trap handlers and the output is in single-precision.Previous work on asynchronous floating-point arithmetic units have mostly focused on single operationssuch as division. This is the first work to the authors' knowledge that can perform floating-point addition,multiplication, division, and remainder using a common datapath.
Floating-Point Arithmetic on Round-to-Nearest Representations
Kornerup, Peter; Panhaleux, Adrien
2012-01-01
Recently we introduced a class of number representations denoted RN-representations, allowing an un-biased rounding-to-nearest to take place by a simple truncation. In this paper we briefly review the binary fixed-point representation in an encoding which is essentially an ordinary 2's complement representation with an appended round-bit. Not only is this rounding a constant time operation, so is also sign inversion, both of which are at best log-time operations on ordinary 2's complement representations. Addition, multiplication and division is defined in such a way that rounding information can be carried along in a meaningful way, at minimal cost. Based on the fixed-point encoding we here define a floating point representation, and describe to some detail a possible implementation of a floating point arithmetic unit employing this representation, including also the directed roundings.
Interval Semantics for Standard Floating-Point Arithmetic
Edmonson, W W
2008-01-01
If the non-zero finite floating-point numbers are interpreted as point intervals, then the effect of rounding can be interpreted as computing one of the bounds of the result according to interval arithmetic. We give an interval interpretation for the signed zeros and infinities, so that the undefined operations 0*inf, inf - inf, inf/inf, and 0/0 become defined. In this way no operation remains that gives rise to an error condition. Mathematically questionable features of the floating-point standard become well-defined sets of reals. Interval semantics provides a basis for the verification of numerical algorithms. We derive the results of the newly defined operations and consider the implications for hardware implementation.
ASIC Design of Floating-Point FFT Processor
Institute of Scientific and Technical Information of China (English)
陈禾; 赵忠武
2004-01-01
An application specific integrated circuit (ASIC) design of a 1024 points floating-point fast Fourier transform(FFT) processor is presented. It can satisfy the requirement of high accuracy FFT result in related fields. Several novel design techniques for floating-point adder and multiplier are introduced in detail to enhance the speed of the system. At the same time, the power consumption is decreased. The hardware area is effectively reduced as an improved butterfly processor is developed. There is a substantial increase in the performance of the design since a pipelined architecture is adopted, and very large scale integrated (VLSI) is easy to realize due to the regularity. A result of validation using field programmable gate array (FPGA) is shown at the end. When the system clock is set to 50 MHz, 204.8 μs is needed to complete the operation of FFT computation.
Bifurcated method and apparatus for floating point addition with decreased latency time
Energy Technology Data Exchange (ETDEWEB)
Farmwald, Paul M. (Livermore, CA)
1987-01-01
Apparatus for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.
FPGA Implementation of Double Precision Floating Point Multiplier using Xilinx Coregen Tool
Sukhvir Kaur; Parminder Singh Jassal
2013-01-01
Floating point arithmetic is widely used in many areas, especially scientific computation and signal processing. The main applications of floating points today are in the field of medical imaging, biometrics, motion capture and audio applications. The IEEE floating point standard defines both single precision and double precision formats. Multiplication is a core operation in many signal processing computations, and as such efficient implementation of floating point multipliers is an importan...
Computing Integer Powers in Floating-Point Arithmetic
Kornerup, Peter; Muller, Jean-Michel
2007-01-01
We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is available. We show that our log-time algorithm always produce faithfully-rounded results, discuss the possibility of getting correctly rounded results, and show that results correctly rounded in double precision can be obtained if extended-precision is available with the possibility to round into double precision (with a single rounding).
Computing Integer Powers in Floating-Point Arithmetic
Kornerup, Peter; Lefèvre, Vincent; Muller, Jean-Michel
2007-01-01
We introduce two algorithms for accurately evaluating powers to a positive integer in floating-point arithmetic, assuming a fused multiply-add (fma) instruction is available. We show that our log-time algorithm always produce faithfully-rounded results, discuss the possibility of getting correctly rounded results, and show that results correctly rounded in double precision can be obtained if extended-precision is available with the possibility to round into double precision (with a single rou...
Floating-point array processors evolve into tailorable systems
Energy Technology Data Exchange (ETDEWEB)
Kotelly, G.
1983-05-12
Recently introduced 32-bit floating point array processors (APs) combine configuration flexibility, integrated hardware/software system architecture and real-time computational power to meet a variety of application requirements. APS have now evolved into general-purpose boxes and PC boards which readily adapt to changing OEM needs. Contributing to this greater AP versatility are a variety of hardware and software features. These features are described and the range of available products is surveyed.
Sabrewing: a lightweight architecture for combined floating-point and integer arithmetic
Bruintjes, Tom M.; Walters, Karel H.G.; Gerez, Sabih H.; Molenkamp, Bert; Smit, Gerard J.M.
2012-01-01
In spite of the fact that floating-point arithmetic is costly in terms of silicon area, the joint design of hardware for floating-point and integer arithmetic is seldom considered. While components like multipliers and adders can potentially be shared, floating-point and integer units in contemporar
Sabrewing: A lightweight architecture for combined floating-point and integer arithmetic
Bruintjes, Tom; Walters, K.H.G.; Gerez, Sabih H.; Molenkamp, Egbert; Smit, Gerardus Johannes Maria
In spite of the fact that floating-point arithmetic is costly in terms of silicon area, the joint design of hardware for floating-point and integer arithmetic is seldom considered. While components like multipliers and adders can potentially be shared, floating-point and integer units in
On the Floating Point Performance of the i860 Microprocessor
Lee, King; Kutler, Paul (Technical Monitor)
1997-01-01
The i860 microprocessor is a pipelined processor that can deliver two double precision floating point results every clock. It is being used in the Touchstone project to develop a teraflop computer by the year 2000. With such high computational capabilities it was expected that memory bandwidth would limit performance on many kernels. Measured performance of three kernels showed performance is less than what memory bandwidth limitations would predict. This paper develops a model that explains the discrepancy in terms of memory latencies and points to some problems involved in moving data from memory to the arithmetic pipelines.
Multi-input and binary reproducible, high bandwidth floating point adder in a collective network
Energy Technology Data Exchange (ETDEWEB)
Chen, Dong; Eisley, Noel A.; Heidelberger, Philip; Steinmacher-Burow, Burkhard
2016-11-15
To add floating point numbers in a parallel computing system, a collective logic device receives the floating point numbers from computing nodes. The collective logic devices converts the floating point numbers to integer numbers. The collective logic device adds the integer numbers and generating a summation of the integer numbers. The collective logic device converts the summation to a floating point number. The collective logic device performs the receiving, the converting the floating point numbers, the adding, the generating and the converting the summation in one pass. One pass indicates that the computing nodes send inputs only once to the collective logic device and receive outputs only once from the collective logic device.
Multi-input and binary reproducible, high bandwidth floating point adder in a collective network
Energy Technology Data Exchange (ETDEWEB)
Chen, Dong; Eisley, Noel A; Heidelberger, Philip; Steinmacher-Burow, Burkhard
2015-03-10
To add floating point numbers in a parallel computing system, a collective logic device receives the floating point numbers from computing nodes. The collective logic devices converts the floating point numbers to integer numbers. The collective logic device adds the integer numbers and generating a summation of the integer numbers. The collective logic device converts the summation to a floating point number. The collective logic device performs the receiving, the converting the floating point numbers, the adding, the generating and the converting the summation in one pass. One pass indicates that the computing nodes send inputs only once to the collective logic device and receive outputs only once from the collective logic device.
A floating point engine for lattice gauge calculations
Energy Technology Data Exchange (ETDEWEB)
Husby, D.; Atac, R.; Cook, A.; Deppe, J.; Fischler, M.; Gaines, I.; Wash, T.; Pham, T.; Zmuda, T.
1989-02-01
The latest in low cost computing solutions from the Fermilab Advanced Computer Program is targeted at Lattice Gauge theory calculations and delivers supercomputer performance at a fraction of the cost. A typical system with 256 processors, 2.5 Gigabytes of memory, and 64 Gigabytes of on-line tape storage, delivers a peak performance of 5 billion floating point operations per second. The programming environment, Canopy, provides a comprehensive, hardware independent, distributed processing platform from within the more familiar environments of FORTRAN, C, and UNIX. This paper describes the individual processing elements of the system and gives a brief description of the Canopy software.
Y-MP floating point and Cholesky factorization
Carter, Russell
1991-01-01
The floating point arithmetics implemented in the Cray 2 and Cray Y-MP computer systems are nearly identical, but large scale computations performed on the two systems have exhibited significant differences in accuracy. The difference in accuracy is analyzed for Cholesky factorization algorithm, and it is found that the source of the difference is the subtract magnitude operation of the Cray Y-MP. The results from numerical experiments for a range of problem sizes are presented, and an efficient method for improving the accuracy of the factorization obtained on the Y-MP is presented.
A floating point engine for lattice gauge calculations
Energy Technology Data Exchange (ETDEWEB)
Husby, D.; Atac, R.; Cook, A.; Deppe, J.; Fischler, M.; Gaines, I.; Nash, T.; Pham, T.; Zmuda, T.; Eichten, E.
1988-11-01
The latest in low cost computing solutions from the Fermilab Advanced Computer Program is targeted at Lattice Gauge theory calculations and delivers supercomputer performance at a fraction of the cost. A typical system with 256 processors, 2.5 Gigabytes of memory, and 64 Gigabytes of on-line tape storage, delivers a peak performance of 5 billion floating point operations per second. The programming environment, Canopy, provides a comprehensive, hardware independent, distributed processing platform from within the more familiar environments of FORTRAN, C, and UNIX. This paper describes the individual processing elements of the system and gives a brief description of the Canopy software. 8 refs., 3 figs.
Power Dissipation Challenges in Multicore Floating-Point Units
DEFF Research Database (Denmark)
Liu, Wei; Nannarelli, Alberto
2010-01-01
With increased densities on chips and the growing popularity of multicore processors and general-purpose graphics processing units (GPGPUs) power dissipation and energy consumption pose a serious challenge in the design of system-on-chips (SoCs) and a rise in costs for heat removal. In this work......, we analyze the impact of power dissipation in floating-point (FP) units and we consider different alternatives in the implementation of FP-division that lead to substantial energy savings. We compare the implementation of division in a Fused Multiply-Add (FMA) unit based on the Newton...
JPEG2000 Compatible Lossless Coding of Floating-Point Data
Directory of Open Access Journals (Sweden)
Usevitch BryanE
2007-01-01
Full Text Available Many scientific applications require that image data be stored in floating-point format due to the large dynamic range of the data. These applications pose a problem if the data needs to be compressed since modern image compression standards, such as JPEG2000, are only defined to operate on fixed-point or integer data. This paper proposes straightforward extensions to the JPEG2000 image compression standard which allow for the efficient coding of floating-point data. These extensions maintain desirable properties of JPEG2000, such as lossless and rate distortion optimal lossy decompression from the same coded bit stream, scalable embedded bit streams, error resilience, and implementation on low-memory hardware. Although the proposed methods can be used for both lossy and lossless compression, the discussion in this paper focuses on, and the test results are limited to, the lossless case. Test results on real image data show that the proposed lossless methods have raw compression performance that is competitive with, and sometime exceeds, current state-of-the-art methods.
JPEG2000 Compatible Lossless Coding of Floating-Point Data
Directory of Open Access Journals (Sweden)
Bryan E. Usevitch
2007-02-01
Full Text Available Many scientific applications require that image data be stored in floating-point format due to the large dynamic range of the data. These applications pose a problem if the data needs to be compressed since modern image compression standards, such as JPEG2000, are only defined to operate on fixed-point or integer data. This paper proposes straightforward extensions to the JPEG2000 image compression standard which allow for the efficient coding of floating-point data. These extensions maintain desirable properties of JPEG2000, such as lossless and rate distortion optimal lossy decompression from the same coded bit stream, scalable embedded bit streams, error resilience, and implementation on low-memory hardware. Although the proposed methods can be used for both lossy and lossless compression, the discussion in this paper focuses on, and the test results are limited to, the lossless case. Test results on real image data show that the proposed lossless methods have raw compression performance that is competitive with, and sometime exceeds, current state-of-the-art methods.
A floating-point digital receiver for MRI.
Hoenninger, John C; Crooks, Lawrence E; Arakawa, Mitsuaki
2002-07-01
A magnetic resonance imaging (MRI) system requires the highest possible signal fidelity and stability for clinical applications. Quadrature analog receivers have problems with channel matching, dc offset and analog-to-digital linearity. Fixed-point digital receivers (DRs) reduce all of these problems. We have demonstrated that a floating-point DR using large (order 124 to 512) FIR low-pass filters also overcomes these problems, automatically provides long word length and has low latency between signals. A preloaded table of finite impuls response (FIR) filter coefficients provides fast switching between one of 129 different one-stage and two-stage multrate FIR low-pass filters with bandwidths between 4 KHz and 125 KHz. This design has been implemented on a dual channel circuit board for a commercial MRI system.
FPGA Implementation of Double Precision Floating Point Multiplier using Xilinx Coregen Tool
Directory of Open Access Journals (Sweden)
Sukhvir Kaur
2013-06-01
Full Text Available Floating point arithmetic is widely used in many areas, especially scientific computation and signal processing. The main applications of floating points today are in the field of medical imaging, biometrics, motion capture and audio applications. The IEEE floating point standard defines both single precision and double precision formats. Multiplication is a core operation in many signal processing computations, and as such efficient implementation of floating point multipliers is an important concern. Until now there is the implementation of the low precision floating point formats, but this piece of work considers the implementation of 64-bit double precision multiplier. This paper presents the FPGA implementation of double precision floating point multiplier using Xilinx Coregen Tool.
LifeJacket: Verifying precise floating-point optimizations in LLVM
Nötzli, Andres; Brown, Fraser
2016-01-01
Optimizing floating-point arithmetic is vital because it is ubiquitous, costly, and used in compute-heavy workloads. Implementing precise optimizations correctly, however, is difficult, since developers must account for all the esoteric properties of floating-point arithmetic to ensure that their transformations do not alter the output of a program. Manual reasoning is error prone and stifles incorporation of new optimizations. We present an approach to automate reasoning about floating-point...
1989-12-01
The laser programmable floating point application specific processor (LPASP) is a new approach at rapid development of custom VLSI chips. The LPASP...double precision floating point adder and the laser programmable read-only memory (LPROM) that are macrocells within the LPASP. In addition, the...thesis analyzes the applicability of an LPASP parallel processing system. The double precision floating point adder is an adder/subtractor macrocell
Hunhold, Laslo
2017-01-01
This thesis examines a modern concept for machine numbers based on interval arithmetic called 'Unums' and compares it to IEEE 754 floating-point arithmetic, evaluating possible uses of this format where floating-point numbers are inadequate. In the course of this examination, this thesis builds theoretical foundations for IEEE 754 floating-point numbers, interval arithmetic based on the projectively extended real numbers and Unums.
Design of a Floating-Point Fused Add-Subtract Unit Using Verilog
Directory of Open Access Journals (Sweden)
Mayank Sharma,
2013-06-01
Full Text Available A floating-point (FP fused add-subtract unit is presented that performs simultaneous floating-point operation of add-subtract on a common pair of single-precision data at the same time that it takes to perform in a single addition with a conventional floating-point adder. The system was placed and routed in 45nm process so that there will be less consumption of memory as well as power.
Software implementation of floating-Point arithmetic on a reduced-Instruction-set processor
Energy Technology Data Exchange (ETDEWEB)
Gross, T.
1985-11-01
Current single chip implementations of reduced-instruction-set processors do not support hardware floating-point operations. Instead, floating-point operations have to be provided either by a coprocessor or by software. This paper discusses issues arising from a software implementation of floating-point arithmetic for the MIPS processor, an experimental VLSI architecture. Measurements indicate that an acceptable level of performance is achieved, but this approach is no substitute for a hardware accelerator if higher-precision results are required. This paper includes instruction profiles for the basic floating-point operations and evaluates the usefulness of some aspects of the instruction set.
Gschwind, Michael K.
2011-03-01
Mechanisms for implementing a floating point only single instruction multiple data instruction set architecture are provided. A processor is provided that comprises an issue unit, an execution unit coupled to the issue unit, and a vector register file coupled to the execution unit. The execution unit has logic that implements a floating point (FP) only single instruction multiple data (SIMD) instruction set architecture (ISA). The floating point vector registers of the vector register file store both scalar and floating point values as vectors having a plurality of vector elements. The processor may be part of a data processing system.
Paranoia.Ada: A diagnostic program to evaluate Ada floating-point arithmetic
Hjermstad, Chris
1986-01-01
Many essential software functions in the mission critical computer resource application domain depend on floating point arithmetic. Numerically intensive functions associated with the Space Station project, such as emphemeris generation or the implementation of Kalman filters, are likely to employ the floating point facilities of Ada. Paranoia.Ada appears to be a valuabe program to insure that Ada environments and their underlying hardware exhibit the precision and correctness required to satisfy mission computational requirements. As a diagnostic tool, Paranoia.Ada reveals many essential characteristics of an Ada floating point implementation. Equipped with such knowledge, programmers need not tremble before the complex task of floating point computation.
Floating-point processor for INTEL 8080A microprocessor systems
Energy Technology Data Exchange (ETDEWEB)
Bairstow, R.; Barlow, J.; Jires, M.; Waters, M.
1982-03-01
An A.M.D. 9511 Floating Point Processor has been interfaced to the Rutherford Laboratory Bubble Chamber Group's microcomputers. These computers are based on the INTEL 8080A microprocessor. The interface uses a memory mapped I/O technique to ensure rapid transfer of arguments between processors. The A.M.D. 9511 acts as a slave processor to the INTEL 8080A system. The 8080 processor is held in WAIT status until completion of the A.M.D. operation. A software Macro Processor has been written to effectively extend the basic INTEL 8080A instruction set to include the full range of A.M.D. 9511 instructions.
Floating-point systolic array including serial processors
Energy Technology Data Exchange (ETDEWEB)
Leeland, S.B.
1989-10-03
This patent describes, in a systolic array system utilizing a plurality of semiconductor chips, a semiconductor chip. It comprises: a plurality of processing elements each including a floating-point serial processor and a plurality of data storage registers; global bus means coupled to the serial processor of each of the plurality of processing elements for inputing and outputing data to and from each chip and for programming each serial processor; and a plurality of data buses coupled to each of the plurality of data storage registers of each of the plurality of processing elements. The global bus means being coupled to the plurality of data storage registers for programming the data storage registers.
Floating point fault tolerance with backward error assertions
Energy Technology Data Exchange (ETDEWEB)
Boley, D.; Golub, G.H.; Makar, S.; Saxena, N.; Mccluskey, E.J. [Univ. of Minnesota, Minneapolis, MN (United States)
1995-02-01
This paper introduces an assertion scheme based on the backward error analysis for error detection in algorithms that solve dense systems of linear equations, Ax = b. Unlike previous methods, this Backward Error Assertion Model is specifically designed to operate in an environment of floating point arithmetic subject to round-off errors, and it can be easily instrumented in a Watchdog processor environment. The complexity of verifying assertions is Omicron (n(sup 2)), compared to the Omicron (n(sup 3)) complexity of algorithms solving Ax = b. Unlike other proposed error detection methods, this assertion model does not require any encoding of the matrix A. Experimental results under various error models are presented to validate the effectiveness of this assertion scheme. 22 refs.
Floating-Point Numbers with Error Estimates (revised)
Masotti, Glauco
2012-01-01
The study addresses the problem of precision in floating-point (FP) computations. A method for estimating the errors which affect intermediate and final results is proposed and a summary of many software simulations is discussed. The basic idea consists of representing FP numbers by means of a data structure collecting value and estimated error information. Under certain constraints, the estimate of the absolute error is accurate and has a compact statistical distribution. By monitoring the estimated relative error during a computation (an ad-hoc definition of relative error has been used), the validity of results can be ensured. The error estimate enables the implementation of robust algorithms, and the detection of ill-conditioned problems. A dynamic extension of number precision, under the control of error estimates, is advocated, in order to compute results within given error bounds. A reduced time penalty could be achieved by a specialized FP processor. The realization of a hardwired processor incorporat...
Fixed-rate compressed floating-point arrays
Energy Technology Data Exchange (ETDEWEB)
2014-03-30
ZFP is a library for lossy compression of single- and double-precision floating-point data. One of the unique features of ZFP is its support for fixed-rate compression, which enables random read and write access at the granularity of small blocks of values. Using a C++ interface, this allows declaring compressed arrays (1D, 2D, and 3D arrays are supported) that through operator overloading can be treated just like conventional, uncompressed arrays, but which allow the user to specify the exact number of bits to allocate to the array. ZFP also has variable-rate fixed-precision and fixed-accuracy modes, which allow the user to specify a tolerance on the relative or absolute error.
A Design Outline for Floating Point Absorber Wave Energy Converters
Directory of Open Access Journals (Sweden)
Mohammed Faizal
2014-04-01
Full Text Available An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.
Dumas, Jean-Guillaume
2007-01-01
We present an algorithm to perform arithmetic operations over small extension field via numerical routines. The idea is to convert the $X$-adic representation of modular polynomials, with $X$ an indeterminate, to a $q$-adic representation where $q$ is a prime power larger than the field characteristic. With some control on the different involved sizes it is then possible to perform some of the $q$-adic arithmetic directly with floating point operators. Depending also on the number of performed numerical operations one can then convert back to the $q$-adic or $X$-adic representation and eventually mod out high residues. In this note we present a new version of both conversions: more tabulations and a way to reduce the number of divisions involved in the process are presented.
Lossless coding of floating point data with JPEG 2000 Part 10
Gamito, Manuel N.; Salles Dias, Miguel
2004-11-01
JPEG 2000 Part 10 is a new work part of the ISO/IEC JPEG Committee dealing with the extension of JPEG 2000 technologies to three-dimensional data. One of the issues in Part 10 is the ability to encode floating point datasets. Many Part 10 use cases come from the scientific and engineering communities, where floating point data is often produced either from numerical simulations or from remote sensing instruments. This paper presents the technologies that are currently being developed to accommodate this Part 10 requirement. The coding of floating point datasets with JPEG 2000 requires two changes to the coding pipeline. Firstly, the wavelet transformation stage is optimized to correctly decorrelate data represented with the IEEE 754 floating point standard. Special IEEE 754 floating point values like Infinities and NaN's are signaled beforehand as they do not correlate well with other floating point values. Secondly, computation of distortion measures on the encoder side is performed in floating point space, rather than in integer space, in order to correctly perform rate allocation. Results will show that these enhancements to the JPEG 2000 coding pipeline lead to better compression results than Part 1 encoding where the floating point data had been retyped as integers.
Floating-point arithmetic unit for pro-log based control systems
Energy Technology Data Exchange (ETDEWEB)
Macmillan, D.C.
1978-01-01
A floating-point unit was designed for use with control systems based on Pro-Log four-bit or eight-bit microprocessors. The unit consists of a single board which can be pin-connected into existing control systems. It provides the capability for floating-point arithmetic computations, including operations with transcendental and exponential functions. 9 figures, 2 tables.
A hardware error estimate for floating-point computations
Lang, Tomás; Bruguera, Javier D.
2008-08-01
We propose a hardware-computed estimate of the roundoff error in floating-point computations. The estimate is computed concurrently with the execution of the program and gives an estimation of the accuracy of the result. The intention is to have a qualitative indication when the accuracy of the result is low. We aim for a simple implementation and a negligible effect on the execution of the program. Large errors due to roundoff occur in some computations, producing inaccurate results. However, usually these large errors occur only for some values of the data, so that the result is accurate in most executions. As a consequence, the computation of an estimate of the error during execution would allow the use of algorithms that produce accurate results most of the time. In contrast, if an error estimate is not available, the solution is to perform an error analysis. However, this analysis is complex or impossible in some cases, and it produces a worst-case error bound. The proposed approach is to keep with each value an estimate of its error, which is computed when the value is produced. This error is the sum of a propagated error, due to the errors of the operands, plus the generated error due to roundoff during the operation. Since roundoff errors are signed values (when rounding to nearest is used), the computation of the error allows for compensation when errors are of different sign. However, since the error estimate is of finite precision, it suffers from similar accuracy problems as any floating-point computation. Moreover, it is not an error bound. Ideally, the estimate should be large when the error is large and small when the error is small. Since this cannot be achieved always with an inexact estimate, we aim at assuring the first property always, and the second most of the time. As a minimum, we aim to produce a qualitative indication of the error. To indicate the accuracy of the value, the most appropriate type of error is the relative error. However
The complexity of class polynomial computation via floating point approximations
Enge, Andreas
2009-06-01
We analyse the complexity of computing class polynomials, that are an important ingredient for CM constructions of elliptic curves, via complex floating point approximations of their roots. The heart of the algorithm is the evaluation of modular functions in several arguments. The fastest one of the presented approaches uses a technique devised by Dupont to evaluate modular functions by Newton iterations on an expression involving the arithmetic-geometric mean. Under the heuristic assumption, justified by experiments, that the correctness of the result is not perturbed by rounding errors, the algorithm runs in time O left( sqrt {\\vert D\\vert} log^3 \\vert D\\vert M left( sq... ...arepsilon} \\vert D\\vert right) subseteq O left( h^{2 + \\varepsilon} right) for any \\varepsilon > 0 , where D is the CM discriminant, h is the degree of the class polynomial and M (n) is the time needed to multiply two n -bit numbers. Up to logarithmic factors, this running time matches the size of the constructed polynomials. The estimate also relies on a new result concerning the complexity of enumerating the class group of an imaginary quadratic order and on a rigorously proven upper bound for the height of class polynomials.
Singh Naginder; Sasamal Trailokya Nath
2016-01-01
This paper describes a single precision floating point division based on Newton-Raphson computational division algorithm. The Newton-Raphson computational algorithm is implemented using 32-bit floating point multi-plier and subtractor. The salient feature of this proposed design is that the module for computing mantissa in 32-floating point multiplier is designed using a 24-bit Vedic multiplication (Urdhva-triyakbhyam-sutra) technique. 32-bit floating point multiplier, designed using Vedic mu...
Low Power Floating Point Computation Sharing Multiplier for Signal Processing Applications
Directory of Open Access Journals (Sweden)
Sivanantham S
2013-04-01
Full Text Available Design of low power, higher performance digital signal processing elements are the major requirements in ultra deep sub-micron technology. This paper presents an IEEE-754 standard compatible single precision Floating-point Computation SHaring Multiplier (FCSHM scheme suitable for low-power and high-speed signal processing applications. The floating-point multiplier used at thefilter taps effectively uses the computation re-use concept. Experimental results on a 10-tap programmable FIR filter show that the proposed multiplier scheme can provide a power reduction of 39.7% and significant improvements in the performance compared to conventional floating-point carry save array multiplier implementations.
Apparatus and method for implementing power saving techniques when processing floating point values
Energy Technology Data Exchange (ETDEWEB)
Kim, Young Moon; Park, Sang Phill
2017-10-03
An apparatus and method are described for reducing power when reading and writing graphics data. For example, one embodiment of an apparatus comprises: a graphics processor unit (GPU) to process graphics data including floating point data; a set of registers, at least one of the registers of the set partitioned to store the floating point data; and encode/decode logic to reduce a number of binary 1 values being read from the at least one register by causing a specified set of bit positions within the floating point data to be read out as 0s rather than 1s.
FPGA-based floating-point datapath design for geometry processing
Xing, Shanzhen; Yu, William W.
1998-10-01
Geometry processing comprises of a great many computationally intensive floating-point operations. Real- time graphics systems generally use application-specific custom designed parallel hardware to provide the high performance computation power. When designing a graphics engine on a FPGA-based configurable computing system, cost- effectiveness is important. This paper investigates and proposes a cost-effective FPGA-based floating-point datapath for geometry process. It is designed to be a basic building block for FPGA-based geometry processors. The implemented datapath operates at a frequency of 6.25 Mhz and has an average floating-point operation time of 10.2 microseconds.
Automatic Estimation of Verified Floating-Point Round-Off Errors via Static Analysis
Moscato, Mariano; Titolo, Laura; Dutle, Aaron; Munoz, Cesar A.
2017-01-01
This paper introduces a static analysis technique for computing formally verified round-off error bounds of floating-point functional expressions. The technique is based on a denotational semantics that computes a symbolic estimation of floating-point round-o errors along with a proof certificate that ensures its correctness. The symbolic estimation can be evaluated on concrete inputs using rigorous enclosure methods to produce formally verified numerical error bounds. The proposed technique is implemented in the prototype research tool PRECiSA (Program Round-o Error Certifier via Static Analysis) and used in the verification of floating-point programs of interest to NASA.
Lightweight Floating-Point Arithmetic: Case Study of Inverse Discrete Cosine Transform
Directory of Open Access Journals (Sweden)
Fang Fang
2002-09-01
Full Text Available To enable floating-point (FP signal processing applications in low-power mobile devices, we propose lightweight floating-point arithmetic. It offers a wider range of precision/power/speed/area trade-offs, but is wrapped in forms that hide the complexity of the underlying implementations from both multimedia software designers and hardware designers. Libraries implemented in C++ and Verilog provide flexible and robust floating-point units with variable bit-width formats, multiple rounding modes and other features. This solution bridges the design gap between software and hardware, and accelerates the design cycle from algorithm to chip by avoiding the translation to fixed-point arithmetic. We demonstrate the effectiveness of the proposed scheme using the inverse discrete cosine transform (IDCT, in the context of video coding, as an example. Further, we implement lightweight floating-point IDCT into hardware and demonstrate the power and area reduction.
Lightweight Floating-Point Arithmetic: Case Study of Inverse Discrete Cosine Transform
Fang, Fang; Chen, Tsuhan; Rutenbar, Rob A.
2002-12-01
To enable floating-point (FP) signal processing applications in low-power mobile devices, we propose lightweight floating-point arithmetic. It offers a wider range of precision/power/speed/area trade-offs, but is wrapped in forms that hide the complexity of the underlying implementations from both multimedia software designers and hardware designers. Libraries implemented in C++ and Verilog provide flexible and robust floating-point units with variable bit-width formats, multiple rounding modes and other features. This solution bridges the design gap between software and hardware, and accelerates the design cycle from algorithm to chip by avoiding the translation to fixed-point arithmetic. We demonstrate the effectiveness of the proposed scheme using the inverse discrete cosine transform (IDCT), in the context of video coding, as an example. Further, we implement lightweight floating-point IDCT into hardware and demonstrate the power and area reduction.
Zoev, I. V.; Beresnev, A. P.; Mytsko, E. A.; Malchukov, A. N.
2017-02-01
An important aspect of modern automation is machine learning. Specifically, neural networks are used for environment analysis and decision making based on available data. This article covers the most frequently performed operations on floating-point numbers in artificial neural networks. Also, a selection of the optimum value of the bit to 14-bit floating-point numbers for implementation on FPGAs was submitted based on the modern architecture of integrated circuits. The description of the floating-point multiplication (multiplier) algorithm was presented. In addition, features of the addition (adder) and subtraction (subtractor) operations were described in the article. Furthermore, operations for such variety of neural networks as a convolution network - mathematical comparison of a floating point (‘less than’ and ‘greater than or equal’) were presented. In conclusion, the comparison with calculating units of Atlera was made.
Proposed radix- and word-length-independent standard for floating-point arithmetic
Energy Technology Data Exchange (ETDEWEB)
Cody, W.J.; Coonen, J.T.; Gay, D.M.; Hanson, K.; Hough, D.; Kahan, W.; Karpinski, R.; Palmer, J.; Ris, F.N.; Stevenson, D.
1984-01-01
The Microprocessor Standards Committee of the IEEE Computer Society sponsors two groups drafting proposed standards for floating-point arithmetic. The first, Task P754, reported Draft 10.0 of a Proposed Standard for Binary Floating-point Arithmetic out of committee in December, 1982. The document is now a de facto standard and is progressing slowly through the approval process within the IEEE Computer Society. In August 1983, the second group, Task P854, completed Draft 1.0 of a Proposed Radix- and Word-length independent Standard for Floating-point Arithmetic that generalizes and is upward compatible with the IEEE Proposed Standard for Binary Floating-point Arithmetic. This article places their contents before the public for the first time. 10 references, 3 tables.
Institute of Scientific and Technical Information of China (English)
吴俊; 胡协和; 陈生; 褚健
2003-01-01
The closed-loop stability issue of finite-precision realizations was investigated for digital controllers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resulting from using finite word length (FWL) block-floating-point representation scheme. A block-floating-point FWL closed-loop stability measure was derived which considers both the dynamic range and precision. To facilitate the design of optimal finite-precision controller realizations, a computationally tractable block-floating-point FWL closed-loop stability measure was then introduced and the method of computing the value of this measure for a given controller realization was developed. The optimal controller realization is defined as the solution that maximizes the corresponding measure, and a numerical optimization approach was adopted to solve the resulting optimal realization problem. A numerical example was used to illustrate the design procedure and to compare the optimal controller realization with the initial realization.
Institute of Scientific and Technical Information of China (English)
吴俊; 胡协和; 陈生; 褚健
2003-01-01
The closed-loop stability issue of finite-precision realizations was investigated for digital control-lers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resultingfrom using finite word length (FWL) block-floating-point representation scheme. A block-floating-point FWL closed-loop stability measure was derived which considers both the dynamic range and precision. To facilitate the design of optimal finite-precision controller realizations, a computationally tractable block-floating-point FWL closed-loop stability measure was then introduced and the method of computing the value of this measure for a given controller realization was developed. The optimal controller realization is defined as the solution that maximizes the corresponding measure, and a numerical optimization approach was adopted to solve the resulting optimal realization problem. A numerical example was used to illustrate the design procedure and to compare the optimal controller realization with the initial realization.
Numerical modelling of wave energy absorption by a floating point absorber system
Energy Technology Data Exchange (ETDEWEB)
Backer, G. De; Banasiak, R.; Beels, C. [Ghent University Civil Engineering Department, Zwijnaarde (Belgium); J. De Rouck, J. De
2007-07-01
Point absorbers are wave energy converters (WECs) consisting of small (floating) bodies oscillating with either one or more degrees of freedom. They can either move with respect to a fixed reference, or with respect to a floating reference. Different buoy geometries are evaluated to obtain the ideal values of size, shape and draft with regard to power absorption for a given moderate wave climate. In this paper, the performance of a heaving point absorber in a floating platform is analysed in a linear way.
Multipliers for Floating-Point Double Precision and Beyond on FPGAs
Banescu, Sebastian; De Dinechin, Florent; Pasca, Bogdan; Tudoran, Radu
2010-01-01
International audience; The implementation of high-precision floating-point applications on reconfigurable hardware requires a variety of large multipliers: Standard multipliers are the core of floating-point multipliers; Truncated multipliers, trading resources for a well-controlled accuracy degradation, are useful building blocks in situations where a full multiplier is not needed. This work studies the automated generation of such multipliers using the embedded multipliers and adders prese...
Low Power Floating Point Computation Sharing Multiplier for Signal Processing Applications
Sivanantham S; Jagannadha Naidu K; Balamurugan S; Bhuvana Phaneendra D
2013-01-01
Design of low power, higher performance digital signal processing elements are the major requirements in ultra deep sub-micron technology. This paper presents an IEEE-754 standard compatible single precision Floating-point Computation SHaring Multiplier (FCSHM) scheme suitable for low-power and high-speed signal processing applications. The floating-point multiplier used at thefilter taps effectively uses the computation re-use concept. Experimental results on a 10-tap programmable FIR filter...
An analysis of the instantaneous floating point amplifier in DFS-V seismic recording system
Energy Technology Data Exchange (ETDEWEB)
Benji, W.
1987-04-01
Instantaneous floating point amplifier is a key unit in digital seismic system. The detailed description is given of circuits, functions and mechanisms of major constituents of the instantaneous floating point amplifier in DFS-V seismic system; and the process of gain adjustment of signal sample is analysed in the paper. A comment on its distinctive zero drift correction method is made. The concrete measure is put forward to cope with the problem in digital offset filtering taken in DFS-V system.
Floating point software package for use on LSI-11 computers at SLAC
Energy Technology Data Exchange (ETDEWEB)
Hendra, R.G.
1981-06-01
A floating point software package has been devised to allow full use of the floating point hardware of the LSI-11 and MODEL40 computers. The procedures are written for the most part in the PL-11 language. The package may be run under the RT-11 operating system, or in RAM or EPROM as part of the KERNEL package. The current set of procedures has been run successfully in all three modes.
Generalization of the proposed IEEE standard for floating-point arithmetic
Energy Technology Data Exchange (ETDEWEB)
Cody, W.J.
1982-12-10
Several years ago the Microprocessor Standards Committee of the IEEE Computer Society established a Floating-Point Working Group to draft a standard binary floating-point arithmetic on 32-bit microprocessors. As that task neared completion, a second working group was established to generalize the proposed binary standard for other radices and wordlengths. We discuss the emerging generalization, its influence on final deliberations on the proposed binary standard, and the implications for numerical computation.
Computer Arithmetic Algorithms for Mega-Digit Floating Point Numbers' Precision
Directory of Open Access Journals (Sweden)
Musbah J. Aqel
2007-01-01
Full Text Available IEEE standard 754 floating point is the most common representation used for floating point numbers, and many computer arithmetic algorithms are developed for basic operations on this standard. In this study, new computer algorithms are proposed to increase the precision range and to solve some problems that are available while using these algorithms. However, these algorithms provide an optional range of required accuracy (Mega-Digit precision to meet new computer's applications.
Analysis of Floating-point Usage%浮点数用法分析
Institute of Scientific and Technical Information of China (English)
杜叔强; 施武祖
2012-01-01
The storage format,distribution,maximum interval,and effective digital of IEEE754 standard floating-point is analyzed and the principle of using floating point number is summarized.%分析了IEEE754标准浮点数的存储格式、在数轴上的分布、最大值、最大间隔以及有效数字,总结了浮点数使用时的原则.
Algorithm XXX : functions to support the IEEE standard for binary floating-point arithmetic.
Energy Technology Data Exchange (ETDEWEB)
Cody, W. J.; Mathematics and Computer Science
1993-12-01
This paper describes C programs for the support functions copysign(x,y), logb(x), scalb(x,n), nextafter(x,y), finite(x), and isnan(x) recommended in the Appendix to the IEEE Standard for Binary Floating-Point Arithmetic. In the case of logb, the modified definition given in the later IEEE Standard for Radix-Independent Floating-Point Arithmetic is followed. These programs should run without modification on most systems conforming to the binary standard.
Patil, Dinesh; Das, Niva; Routray, Aurobinda
2011-01-01
The main focus of the paper is to bring out the differences in performance related issues of Fast-ICA algorithm associated with floating point and fixed point digital signal processing (DSP) platforms. The DSP platforms consisting of TMS320C6713 floating point processor and TMS320C6416 fixed point processor from Texas Instruments have been chosen for this purpose. To study the consistency of performance, the algorithm has been subjected to three different test cases comprising of a mixture of synthetic signals, a mixture of speech signals and a mixture of synthetic signals in presence of noise, respectively. The performance of the Fast-ICA algorithm on floating point and fixed point platform are compared on the basis of accuracy of separation and execution time. Experimental results show insignificant differences in the accuracy of separation and execution time obtained from fixed point processor when compared with those obtained from floating point processor. This clearly strengthens the feasibility issue concerning hardware realization of Fast-ICA on fixed point platform for specific applications.
A Flexible VHDL Floating Point Module for Control Algorithm Implementation in Space Applications
Padierna, A.; Nicoleau, C.; Sanchez, J.; Hidalgo, I.; Elvira, S.
2012-08-01
The implementation of control loops for space applications is an area with great potential. However, the characteristics of this kind of systems, such as its wide dynamic range of numeric values, make inadequate the use of fixed-point algorithms.However, because the generic chips available for the treatment of floating point data are, in general, not qualified to operate in space environments and the possibility of using an IP module in a FPGA/ASIC qualified for space is not viable due to the low amount of logic cells available for these type of devices, it is necessary to find a viable alternative.For these reasons, in this paper a VHDL Floating Point Module is presented. This proposal allows the design and execution of floating point algorithms with acceptable occupancy to be implemented in FPGAs/ASICs qualified for space environments.
Design of the IBM RISC System/6000 floating-point execution unit
Energy Technology Data Exchange (ETDEWEB)
Montoye, R.K.; Hokenek, E. (International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center); Runyon, S.L. (IBM Advanced Workstations Div., Austin, TX (US))
1990-01-01
The IBM RISC System/6000 (RS/6000) floating-point unit (FPU) exemplifies a second-generation RISC CPU architecture and an implementation which greatly increases floating-point performance and accuracy. The key feature of the FPU is a unified floating-point multiply-add-fused unit (MAF) which performs the accumulate operation ({ital A} {times} {ital B}) + {ital C} as an indivisible operation. This single functional unit reduces the latency for chained floating-point operations, as well as rounding errors and chip busing. It also reduces the number of adders/normalizers by combining the addition required for fast multiplication with accumulation. The MAF unit is made practical by a unique fast-shifter, which eases the overlap of multiplication and addition, and a leading-zero/one anticipator, which eases overlap of normalization and addition. The accumulate instruction required by this architecture reduces the instruction path length by combining two instructions into one. Additionally, the RS/6000 FPU is tightly coupled to the rest of the CPU, unlike typical floating-point coprocessor chips.
Implementation of neural network hardware based on a floating point operation in an FPGA
Kim, Jeong-Seob; Jung, Seul
2007-12-01
This paper presents a hardware design and implementation of the radial basis function (RBF) neural network (NN) by the hardware description language. Due to its nonlinear characteristics, it is very difficult to implement for a system with integer-based operation. To develop nonlinear functions such sigmoid functions or exponential functions, floating point operations are required. The exponential function is designed based on the 32bit single-precision floating-point format. In addition, to update weights in the network, the back-propagation algorithm is also implemented in the hardware. Most operations are performed in the floating-point based arithmetic unit and accomplished sequentially by the instruction order stored in ROM. The NN is implemented and tested on the Altera FPGA "Cyclone2 EP2C70F672C8" for nonlinear classifications.
FPGA Based Implementation of Pipelined 32-bit RISC Processor with Floating Point Unit
Directory of Open Access Journals (Sweden)
Jinde Vijay Kumar
2014-04-01
Full Text Available This paper presents 32-bit RISC processor with floating point unit to be designed using pipelined architecture; through this we can improve the speed of the operation as well as overall performance. This processor is developed especially for Arithmetic operations of both fixed and floating point numbers, branch and logical functions. The proposed architecture is able to prevent pipelining from flushing when branch instruction occurs and able to provide halt support. Floating point operations are widely used these days for many applications ranging from graphics application to medical imaging. Thus, the processor can be used for diversified application area. The necessary code is written in the hardware description language Verilog HDL. Quartus II 10.1 suite is used for software development; Modelsim is used for simulations and then implementation on Altera DE 2 FPGA board. Keywords -
Combined Integer and Variable Precision (CIVP) Floating Point Multiplication Architecture for FPGAs
Thapliyal, Himanshu; Bajpai, Rajnish; Sharma, Kamal K
2007-01-01
In this paper, we propose an architecture/methodology for making FPGAs suitable for integer as well as variable precision floating point multiplication. The proposed work will of great importance in applications which requires variable precision floating point multiplication such as multi-media processing applications. In the proposed architecture/methodology, we propose the replacement of existing 18x18 bit and 25x18 bit dedicated multipliers in FPGAs with dedicated 24x24 bit and 24x9 bit multipliers, respectively. We have proved that our approach of providing the dedicated 24x24 bit and 24x9 bit multipliers in FPGAs will make them efficient for performing integer as well as single precision, double precision, and Quadruple precision floating point multiplications.
Interval Slopes as Numerical Abstract Domain for Floating-Point Variables
Chapoutot, Alexandre
2010-01-01
The design of embedded control systems is mainly done with model-based tools such as Matlab/Simulink. Numerical simulation is the central technique of development and verification of such tools. Floating-point arithmetic, that is well-known to only provide approximated results, is omnipresent in this activity. In order to validate the behaviors of numerical simulations using abstract interpretation-based static analysis, we present, theoretically and with experiments, a new relational abstract domain dedicated to floating-point variables. It comes from interval expansion of non-linear functions using slopes and it is able to mimic all the behaviors of the floating-point arithmetic. It is hence adapted to prove the absence of run-time errors or to analyze the numerical precision of embedded control systems.
Gschwind, Michael K
2013-04-16
Mechanisms for generating and executing programs for a floating point (FP) only single instruction multiple data (SIMD) instruction set architecture (ISA) are provided. A computer program product comprising a computer recordable medium having a computer readable program recorded thereon is provided. The computer readable program, when executed on a computing device, causes the computing device to receive one or more instructions and execute the one or more instructions using logic in an execution unit of the computing device. The logic implements a floating point (FP) only single instruction multiple data (SIMD) instruction set architecture (ISA), based on data stored in a vector register file of the computing device. The vector register file is configured to store both scalar and floating point values as vectors having a plurality of vector elements.
Leading-zero anticipator (LZA) in the IBM RISC System/6000 floating-point execution unit
Energy Technology Data Exchange (ETDEWEB)
Hokenek, E.; Montoye, R.K. (International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center)
1990-01-01
This paper presents a technique used in the multiply-add-fused (MAF) unit of the IBM RISC System/6000 (RS/6000) processor for normalizing the floating-point results. Unlike the conventional procedures applied thus far, the so-called leading-zero anticipator (LZA) of the RS/6000 carries out processing of the leading zeros and ones in parallel with floating-point addition. Therefore, the new circuitry reduces the total latency of the MAF unit by enabling the normalization and addition to take place in a single cycle.
A comparison of floating point and logarithmic number systems for FPGAs.
Energy Technology Data Exchange (ETDEWEB)
Hauck, Scott (University of Washington, Seattle, WA); Wood, Aaron (University of Washington, Seattle, WA); Beauchamp, Michael (University of Washington, Seattle, WA); Haselman, Michael (University of Washington, Seattle, WA); Hemmert, K. Scott; Underwood, Keith Douglas
2005-02-01
There have been many papers proposing the use of logarithmic numbers (LNS) as an alternative to floating point because of simpler multiplication, division and exponentiation computations. However, this advantage comes at the cost of complicated, inexact addition and subtraction, as well as the need to convert between the formats. In this work, we created a parameterized LNS library of computational units and compared them to an existing floating point library. Specifically, we considered multiplication, division, addition, subtraction, and format conversion to determine when one format should be used over the other and when it is advantageous to change formats during a calculation.
FPGA Implementations of Feed Forward Neural Network by using Floating Point Hardware Accelerators
Directory of Open Access Journals (Sweden)
Gabriele-Maria Lozito
2014-01-01
Full Text Available This paper documents the research towards the analysis of different solutions to implement a Neural Network architecture on a FPGA design by using floating point accelerators. In particular, two different implementations are investigated: a high level solution to create a neural network on a soft processor design, with different strategies for enhancing the performance of the process; a low level solution, achieved by a cascade of floating point arithmetic elements. Comparisons of the achieved performance in terms of both time consumptions and FPGA resources employed for the architectures are presented.
Inversion of Extremely Ill-Conditioned Matrices in Floating-Point
Rump, Siegfried M.
2009-01-01
Let an $n\\times n$ matrix $A$ of floating-point numbers in some format be given. Denote the relative rounding error unit of the given format by $\\mathtt{eps}$. Assume $A$ to be extremely ill-conditioned, that is $\\cond(A)\\gg\\mathtt{eps}^{-1}$. In about 1984 I developed an algorithm to calculate an approximate inverse of $A$ solely using the given floating-point format. The key is a multiplicative correction rather than a Newton-type additive correction. I did not publish it ...
Energy Technology Data Exchange (ETDEWEB)
Drmac, Z. [Univ. of Colorado, Boulder, CO (United States). Dept. of Computer Science
1997-07-01
In this paper the author considers how to compute the singular value decomposition (SVD) A = U{Sigma}V{sup {tau}} of A = [a{sub 1}, a{sub 2}] {element_of} R{sup mx2} accurately in floating point arithmetic. It is shown how to compute the Jacobi rotation V (the right singular vector matrix) and how to compute AV = U{Sigma} even if the floating point representation of V is the identity matrix. In the case (norm of (a{sub 1})){sub 2} {much_gt} (norm of (a{sub 2})){sub 2}, underflow can produce the identity matrix as the floating point value of V, even for a{sub 1}, a{sub 2} that are far from being mutually orthogonal. This can cause loss of accuracy and failure of convergence of the floating point implementation of the Jacobi method for computing the SVD. The modified Jacobi method recommended in this paper can be implemented as a reliable and highly accurate procedure for computing the SVD of general real matrices whenever the exact singular values do not exceed the underflow or overflow limits.
Towards better segmentation of large floating point 3D astronomical data sets : first results
Moschini, Ugo; Teeninga, Paul; Wilkinson, Michael; Giese, Nadine; Punzo, Davide; van der Hulst, Jan M.; Trager, Scott
2014-01-01
In any image segmentation task, noise must be separated from the actual information and the relevant pixels grouped into objects of interest, on which measures can later be applied. This should be done efficiently on large astronomical surveys with floating point datasets with resolution of the orde
An Efficient Implementation of the Sign LMS Algorithm Using Block Floating Point Format
Chakraborty, Mrityunjoy; Shaik, Rafiahamed; Lee, Moon Ho
2007-12-01
An efficient scheme is presented for implementing the sign LMS algorithm in block floating point format, which permits processing of data over a wide dynamic range at a processor complexity and cost as low as that of a fixed point processor. The proposed scheme adopts appropriate formats for representing the filter coefficients and the data. It also employs a scaled representation for the step-size that has a time-varying mantissa and also a time-varying exponent. Using these and an upper bound on the step-size mantissa, update relations for the filter weight mantissas and exponent are developed, taking care so that neither overflow occurs, nor are quantities which are already very small multiplied directly. Separate update relations are also worked out for the step size mantissa. The proposed scheme employs mostly fixed-point-based operations, and thus achieves considerable speedup over its floating-point-based counterpart.
An Efficient Implementation of the Sign LMS Algorithm Using Block Floating Point Format
Directory of Open Access Journals (Sweden)
Moon Ho Lee
2007-01-01
Full Text Available An efficient scheme is presented for implementing the sign LMS algorithm in block floating point format, which permits processing of data over a wide dynamic range at a processor complexity and cost as low as that of a fixed point processor. The proposed scheme adopts appropriate formats for representing the filter coefficients and the data. It also employs a scaled representation for the step-size that has a time-varying mantissa and also a time-varying exponent. Using these and an upper bound on the step-size mantissa, update relations for the filter weight mantissas and exponent are developed, taking care so that neither overflow occurs, nor are quantities which are already very small multiplied directly. Separate update relations are also worked out for the step size mantissa. The proposed scheme employs mostly fixed-point-based operations, and thus achieves considerable speedup over its floating-point-based counterpart.
Asymmetrical floating point array processors, their application to exploration and exploitation
Energy Technology Data Exchange (ETDEWEB)
Geriepy, B.L.
1983-01-01
An asymmetrical floating point array processor is a special-purpose scientific computer which operates under asymmetrical control of a host computer. Although an array processor can receive fixed point input and produce fixed point output, its primary mode of operation is floating point. The first generation of array processors was oriented towards time series information. The next generation of array processors has proved much more versatile and their applicability ranges from petroleum reservoir simulation to speech syntheses. Array processors are becoming commonplace in mining, the primary usage being construction of grids-by usual methods or by kriging. The Australian mining community is among the world's leaders in regard to computer-assisted exploration and exploitation systems. Part of this leadership role must be providing guidance to computer vendors in regard to current and future requirements.
Applying the Z-transform for the static analysis of floating-point numerical filters
Monniaux, David
2007-01-01
Digital linear filters are used in a variety of applications (sound treatment, control/command, etc.), implemented in software, in hardware, or a combination thereof. For safety-critical applications, it is necessary to bound all variables and outputs of all filters. We give a compositional, effective abstraction for digital linear filters expressed as block diagrams, yielding sound, precise bounds for fixed-point or floating-point implementations of the filters.
Improving Performance of Software Implemented Floating Point Addition
DEFF Research Database (Denmark)
Hindborg, Andreas Erik; Karlsson, Sven
2011-01-01
We outline and evaluate hardware extensions to an integer processor pipeline which allow IEEE 754 oating point, FP, addition to be eciently implemented in software. With a very moderate increase in hardware resources, our perfor- mance evaluation shows that, for a benchmark that executes 12.5% FP...... addition instructions, our approach exhibits a rel- ative slowdown of 3.38 to 15.15 as compared to dedicated hardware. This is a signicant improvement of pure software emulation which leads to relative slowdowns up to 45.33....
Directory of Open Access Journals (Sweden)
Singh Naginder
2016-01-01
Full Text Available This paper describes a single precision floating point division based on Newton-Raphson computational division algorithm. The Newton-Raphson computational algorithm is implemented using 32-bit floating point multi-plier and subtractor. The salient feature of this proposed design is that the module for computing mantissa in 32-floating point multiplier is designed using a 24-bit Vedic multiplication (Urdhva-triyakbhyam-sutra technique. 32-bit floating point multiplier, designed using Vedic multiplication technique, yields a higher computational speed, hence, is efficiently used in floating point divider. Another important feature is the efficient use of device utilization parame-ters and reduced power consumption. An advantage of the Newton-Raphson algorithm is the higher versatility and precision. For representing 32-bit floating point numbers, IEEE 754 standard format is used. ISim simulator is used for simulation. The proposed floating point divider is designed using Verilog Hardware Description Language (HDL and is verified on Xilinx Spartan 6 SP605 Evaluation Platform FPGA.
A non-local method for robustness analysis of floating point programs
Directory of Open Access Journals (Sweden)
Ivan Gazeau
2012-07-01
Full Text Available Robustness is a standard correctness property which intuitively means that if the input to the program changes less than a fixed small amount then the output changes only slightly. This notion is useful in the analysis of rounding error for floating point programs because it helps to establish bounds on output errors introduced by both measurement errors and by floating point computation. Compositional methods often do not work since key constructs—like the conditional and the while-loop—are not robust. We propose a method for proving the robustness of a while-loop. This method is non-local in the sense that instead of breaking the analysis down to single lines of code, it checks certain global properties of its structure. We show the applicability of our method on two standard algorithms: the CORDIC computation of the cosine and Dijkstra's shortest path algorithm.
An analysis of the double-precision floating-point FFT on FPGAs.
Energy Technology Data Exchange (ETDEWEB)
Hemmert, K. Scott; Underwood, Keith Douglas
2005-01-01
Advances in FPGA technology have led to dramatic improvements in double precision floating-point performance. Modern FPGAs boast several GigaFLOPs of raw computing power. Unfortunately, this computing power is distributed across 30 floating-point units with over 10 cycles of latency each. The user must find two orders of magnitude more parallelism than is typically exploited in a single microprocessor; thus, it is not clear that the computational power of FPGAs can be exploited across a wide range of algorithms. This paper explores three implementation alternatives for the fast Fourier transform (FFT) on FPGAs. The algorithms are compared in terms of sustained performance and memory requirements for various FFT sizes and FPGA sizes. The results indicate that FPGAs are competitive with microprocessors in terms of performance and that the 'correct' FFT implementation varies based on the size of the transform and the size of the FPGA.
Lossy compression of floating point high-dynamic range images using JPEG2000
Springer, Dominic; Kaup, Andre
2009-01-01
In recent years, a new technique called High Dynamic Range (HDR) has gained attention in the image processing field. By representing pixel values with floating point numbers, recorded images can hold significantly more luminance information than ordinary integer images. This paper focuses on the realization of a lossy compression scheme for HDR images. The JPEG2000 standard is used as a basic component and is efficiently integrated into the compression chain. Based on a detailed analysis of the floating point format and the human visual system, a concept for lossy compression is worked out and thoroughly optimized. Our scheme outperforms all other existing lossy HDR compression schemes and shows superior performance both at low and high bitrates.
A non-local method for robustness analysis of floating point programs
Gazeau, Ivan; Palamidessi, Catuscia
2012-01-01
Robustness is a standard correctness property which intuitively means that if the input to the program changes less than a fixed small amount then the output changes only slightly. This notion is useful in the analysis of rounding error for floating point programs because it helps to establish bounds on output errors introduced by both measurement errors and by floating point computation. Compositional methods often do not work since key constructs---like the conditional and the while-loop---are not robust. We propose a method for proving the robustness of a while-loop. This method is non-local in the sense that instead of breaking the analysis down to single lines of code, it checks certain global properties of its structure. We show the applicability of our method on two standard algorithms: the CORDIC computation of the cosine and Dijkstra's shortest path algorithm.
A Novel Efficient VLSI Architecture for IEEE 754 Floating point multiplier using Modified CSA
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Nishi Pandey
2015-10-01
Full Text Available Due to advancement of new technology in the field of VLSI and Embedded system, there is an increasing demand of high speed and low power consumption processor. Speed of processor greatly depends on its multiplier as well as adder performance. In spite of complexity involved in floating point arithmetic, its implementation is increasing day by day. Due to which high speed adder architecture become important. Several adder architecture designs have been developed to increase the efficiency of the adder. In this paper, we introduce an architecture that performs high speed IEEE 754 floating point multiplier using modified carry select adder (CSA. Modified CSA depend on booth encoder (BEC Technique. Booth encoder, Mathematics is an ancient Indian system of Mathematics. Here we are introduced two carry select based design. These designs are implementation Xilinx Vertex device family
Manos, P.; Turner, L. R.
1972-01-01
Approximations which can be evaluated with precision using floating-point arithmetic are presented. The particular set of approximations thus far developed are for the function TAN and the functions of USASI FORTRAN excepting SQRT and EXPONENTIATION. These approximations are, furthermore, specialized to particular forms which are especially suited to a computer with a small memory, in that all of the approximations can share one general purpose subroutine for the evaluation of a polynomial in the square of the working argument.
An Effective Leading Zero Anticipation for High Speed Floating Point Addition and Subtraction
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Satish Paidi
2012-06-01
Full Text Available A new leading-zero anticipatory (LZA logic for high-speed floating-point addition and subtraction is proposed. The pre-decoding for normalization concurrently with addition for the significant is carried out in this logic. Shift operation of normalization in parallel with the rounding operation is also performed. The use of simple Boolean algebra allows the proposed logic to be constructed from a simple CMOS circuit.
Energy Technology Data Exchange (ETDEWEB)
Brengle, T.A.; Maron, N.
1980-03-27
Results are presented of comparative timing tests made by running a typical FORTRAN physics simulation code on the following machines: DEC PDP-10 with KI processor; DEC PDP-10, KI processor, and FPS AP-190L; CDC 7600; and CRAY-1. Factors such as DMA overhead, code size for the AP-190L, and the relative utilization of floating point functional units for the different machines are discussed. 1 table.
Achieving subword parallelism by software reuse of the floating-point data path
Zucker, Daniel F.; Lee, Ruby B.; Flynn, Michael J.
1997-01-01
Many increasingly important applications, such as video compression, graphics, or other multimedia applications, require only 8 or 16 bit data words. Using the full 64 bit data path available in most computers to perform these low- precision calculations is an inefficient use of resources. Many manufacturers have addressed this problem by introducing new instructions that allow the packing of subword quantities into a full data word. This paper presents a new software-only technique that accomplishes this same objective by packing subword integer quantities into a double precision floating point word. This technique works even in machines that have not been specially modified with new multimedia instructions. While the idea of packing subword integer quantities into a larger integer data word has been proposed before, this technique is unique in packing integer subwords into a single floating point word with a shared exponent. The traditional floating point arithmetic operations of add, subtract, and multiply are used to pack and unpack the subword quantities. Therefore, the algorithm will work on any machine that supports the IEEE double precision floating point arithmetic standard with no machine-specific code required. Furthermore, the methodology can be implemented in a high-level language such as C. In this paper we describe this technique in general and then demonstrate its validity by implementing it in a public domain mpeg decoder application, mpeg_play distributed by the Berkeley Plateau Multimedia Research Group. We achieved an average speed-up of 13.8%. While there is some degradation in quality because calculations are carried out with lower precision, there is no noticeable difference in image appearance. A quantitative comparison of the image quality is presented.
Interpretation of IEEE-854 floating-point standard and definition in the HOL system
Carreno, Victor A.
1995-01-01
The ANSI/IEEE Standard 854-1987 for floating-point arithmetic is interpreted by converting the lexical descriptions in the standard into mathematical conditional descriptions organized in tables. The standard is represented in higher-order logic within the framework of the HOL (Higher Order Logic) system. The paper is divided in two parts with the first part the interpretation and the second part the description in HOL.
Hormigo, Javier; Julio, Villalba
2016-01-01
This paper analyzes the benefits of using HUB formats to implement floating-point arithmetic under round-tonearest mode from a quantitative point of view. Using HUB formats to represent numbers allows the removal of the rounding logic of arithmetic units, including sticky-bit computation. This is shown for floating-point adders, multipliers, and converters. Experimental analysis demonstrates that HUB formats and the corresponding arithmetic units maintain the same accurac...
Image data compression using a new floating-point digital signal processor.
Siegel, E L; Templeton, A W; Hensley, K L; McFadden, M A; Baxter, K G; Murphey, M D; Cronin, P E; Gesell, R G; Dwyer, S J
1991-08-01
A new dual-ported, floating-point, digital signal processor has been evaluated for compressing 512 and 1,024 digital radiographic images using a full-frame, two-dimensional, discrete cosine transform (2D-DCT). The floating point digital signal processor operates at 49.5 million floating point instructions per second (MFLOPS). The level of compression can be changed by varying four parameters in the lossy compression algorithm. Throughput times were measured for both 2D-DCT compression and decompression. For a 1,024 x 1,024 x 10-bit image with a compression ratio of 316:1, the throughput was 75.73 seconds (compression plus decompression throughput). For a digital fluorography 1,024 x 1,024 x 8-bit image and a compression ratio of 26:1, the total throughput time was 63.23 seconds. For a computed tomography image of 512 x 512 x 12 bits and a compression ratio of 10:1 the throughput time was 19.65 seconds.
High-performance floating-point processor. Koseino fudo shosuten processor
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Fukuhisa, H.; Ide, N.; Tago, H. (Toshiba Corp., Tokyo (Japan))
1993-07-01
A 64-bit high-performance floating-point processing unit (FPU) to be built in a RISC-type CPU was developed. This FPU conforms to the IEEE 754 standard. The FPU contains an arithmetic logic unit (ALU), a multiply/divide unit (MDU), and a register file. The FPU employs a two-scaler pipeline system that can start executing simultaneously two commands processed in the ALU and the MDU. The FPU uses a working frequency of 80 MHz, a chip area of 61 mm[sup 2], and a 0.5 [mu] m CMOS three-layered aluminum wiring as a process, and operates on 3.3 V. It is disposed with a twin-single computation function, a strong full bypass function, and exception prediction capability. A peak performance was obtained in the operation speed at 320 M floating-point operations per second. This FPU is expected to improve the floating-point operation performance when used in a lap-top EWS. 3 refs., 5 figs., 2 tabs.
Bifurcated method and apparatus for floating point addition with decreased latency time
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Farmwald, P.M.
1987-01-27
This patent describes a method for performing floating point addition of a pair of floating point binary numbers each expressed as a mantissa and an exponent. The method comprises the steps of alignment of the mantissas, addition of the aligned mantissas and postnormalization of the mantissa of the sum. The improvement described here comprises: comparing the exponents of the two floating point numbers prior to the alignment step; simultaneously performing two separate calculations along first and second separate parallel paths as follows: calculating a first sum in the first path as if the difference of the exponents is either 0 or 1, including performing the alignment step by at most a one place right shift of one mantissa; simultaneously calculating a second sum in the second path as if the difference of the exponents is greater than 1, including performing the postnormalization step by at most a one place shift of the mantissa of the second sum; selecting between the first sum and the second sum after simultaneously performing the two calculations.
On the precision attainable with various floating-point number systems
Brent, Richard P
2010-01-01
For scientific computations on a digital computer the set of real number is usually approximated by a finite set F of "floating-point" numbers. We compare the numerical accuracy possible with difference choices of F having approximately the same range and requiring the same word length. In particular, we compare different choices of base (or radix) in the usual floating-point systems. The emphasis is on the choice of F, not on the details of the number representation or the arithmetic, but both rounded and truncated arithmetic are considered. Theoretical results are given, and some simulations of typical floating-point computations (forming sums, solving systems of linear equations, finding eigenvalues) are described. If the leading fraction bit of a normalized base 2 number is not stored explicitly (saving a bit), and the criterion is to minimize the mean square roundoff error, then base 2 is best. If unnormalized numbers are allowed, so the first bit must be stored explicitly, then base 4 (or sometimes base...
High Performance Hardware Design Of IEEE Floating Point Adder In FPGA With VHDL
Directory of Open Access Journals (Sweden)
2013-07-01
Full Text Available In this paper, we present the design and implementation of a floating-point adder that is compliant with the current draft revision of this standard. We provide synthesis results indicating the estimated area and delay for our design when it is pipelined to various depths.Our work is an important design resource for development of floating-point adder hardware on FPGAs. All sub components within the floating-point adder and known algorithms are researched and implemented to provide versatility and flexibility to designers as an alternative to intellectual property where they have no control over the design. The VHDL code is open source and can be used by designers with proper reference. Each of the sub-operation is researched for different implementations and then synthesized onto a Spartan FPGA device to be chosen for best performance. Our implementation of the standard algorithm occupied 370 slices and had an overall delay of 31 ns. The standard algorithm was pipelined into five stages to run at 100 MHz which took an area of 324 slices and power is 30mw.
An Adaptive Prediction-Based Approach to Lossless Compression of Floating-Point Volume Data.
Fout, N; Ma, Kwan-Liu
2012-12-01
In this work, we address the problem of lossless compression of scientific and medical floating-point volume data. We propose two prediction-based compression methods that share a common framework, which consists of a switched prediction scheme wherein the best predictor out of a preset group of linear predictors is selected. Such a scheme is able to adapt to different datasets as well as to varying statistics within the data. The first method, called APE (Adaptive Polynomial Encoder), uses a family of structured interpolating polynomials for prediction, while the second method, which we refer to as ACE (Adaptive Combined Encoder), combines predictors from previous work with the polynomial predictors to yield a more flexible, powerful encoder that is able to effectively decorrelate a wide range of data. In addition, in order to facilitate efficient visualization of compressed data, our scheme provides an option to partition floating-point values in such a way as to provide a progressive representation. We compare our two compressors to existing state-of-the-art lossless floating-point compressors for scientific data, with our data suite including both computer simulations and observational measurements. The results demonstrate that our polynomial predictor, APE, is comparable to previous approaches in terms of speed but achieves better compression rates on average. ACE, our combined predictor, while somewhat slower, is able to achieve the best compression rate on all datasets, with significantly better rates on most of the datasets.
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Li, Y.; Yu, Y.; Epler, J.; Previsic, M.
2012-04-01
The extraction of energy from ocean waves has gained interest in recent years. The floating-point absorber (FPA) is one of the most promising devices among a wide variety of wave energy conversion technologies. Early theoretical studies mainly focused on understanding the hydrodynamics of the system and on predicting the maximum power that could be extracted by a heaving body. These studies evolve from the investigation of floating-body interactions in offshore engineering and naval architecture disciplines. To our best knowledge, no systematic study has been reported about the investigation of the power generation performance of an FPA with a close-to-commercial design. A series of experimental tests was conducted to investigate the power extraction performance of an FPA system.
Directory of Open Access Journals (Sweden)
Naresh Grover
2014-02-01
Full Text Available Most of the algorithms implemented in FPGAs used to be fixed-point. Floating-point operations are useful for computations involving large dynamic range, but they require significantly more resources than integer operations. With the current trends in system requirements and available FPGAs, floating-point implementations are becoming more common and designers are increasingly taking advantage of FPGAs as a platform for floating-point implementations. The rapid advance in Field-Programmable Gate Array (FPGA technology makes such devices increasingly attractive for implementing floating-point arithmetic. Compared to Application Specific Integrated Circuits, FPGAs offer reduced development time and costs. Moreover, their flexibility enables field upgrade and adaptation of hardware to run-time conditions. A 32 bit floating point arithmetic unit with IEEE 754 Standard has been designed using VHDL code and all operations of addition, subtraction, multiplication and division are tested on Xilinx. Thereafter, Simulink model in MAT lab has been created for verification of VHDL code of that Floating Point Arithmetic Unit in Modelsim.
Reducing the Disk IO Bandwidth Bottleneck through Fast Floating Point Compression using Accelerators
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Ajith Padyana
2014-03-01
Full Text Available Compute-intensive tasks in high-end high performance computing (HPC systems often generate large amounts of data, especially floating-point data that need to be transmitted over the network. Although computation speeds are very high, the overall performance of these applications is affected by the data transfer overhead. Moreover, as data sets are growing in size rapidly, bandwidth limitations pose a serious bottleneck in several scientific applications. Fast floating point compression can ameliorate the bandwidth limitations. If data is compressed well, then the amount of data transfer is reduced. This reduction in data transfer time comes at the expense of the increased computation required by compression and decompression. It is important for compression and decompression rates to be greater than the network bandwidth; otherwise, it will be faster to transmit uncompressed data directly [1]. Accelerators such as Graphics Processing Units (GPU provide much computational power. In this paper, we show that the computational power of GPUs and CellBE processor can be harnessed to provide sufficiently fast compression and decompression for this approach to be effective for data produced by many practical applications. In particularly, we use Holt`s Exponential smoothing algorithm from time series analysis, and encode the difference between its predictions and the actual data. This yields a lossless compression scheme. We show that it can be implemented efficiently on GPUs and CellBE to provide an effective compression scheme for the purpose of saving on data transfer overheads The primary contribution of this work lies in demonstrating the potential of floating point compression in reducing the I/O bandwidth bottleneck on modern hardware for important classes of scientific applications.
Institute of Scientific and Technical Information of China (English)
何军; 田增; 郭勇; 陈诚
2013-01-01
Considering the shortcoming that the Fused Multiply-Add(FMA) unit increases the latency of separate floating-point add/subs tract and multiply operations,the effect of FMA unit latency optimization,reducing the latency of separated floating-point add/subtract and multiply operations from 6 cycles to 4 cycles,on floating-point performance is studied.Based on a homemade processor with FMA unit,the RTL design is modified.The effect of the optimization on floating-point performance is estimated after running SPEC CPU2000 floating-point benchmarks on the hardware emulation acceleration platform.As the results turned out that the floating-point performance of the benchmarks is all improved 5.25％ at most and 1.61％ on average,proving that such optimization in favor of floating-point performance promotion.%浮点融合乘加部件会增加独立浮点加减法、乘法等运算延迟.为克服该缺陷,研究将乘加部件独立乘法、加减法等运算延迟由6拍减为4拍时对浮点性能的影响.以某支持乘加运算的国产处理器为基础,修改相关的RTL级设计代码,利用硬件仿真加速器平台,对SPEC CPU2000浮点测试课题进行评估.实验结果表明,该延迟优化有利于提高浮点性能,最大提高5.25％,平均提高1.61％.
Thapliyal, Himanshu; Arabnia, Hamid R.; Vinod, A. P.
2006-01-01
In this paper, the authors propose the idea of a combined integer and floating point multiplier(CIFM) for FPGAs. The authors propose the replacement of existing 18x18 dedicated multipliers in FPGAs with dedicated 24x24 multipliers designed with small 4x4 bit multipliers. It is also proposed that for every dedicated 24x24 bit multiplier block designed with 4x4 bit multipliers, four redundant 4x4 multiplier should be provided to enforce the feature of self repairability (to recover from the fau...
Application of a floating point systems AP190L array processor to finite element analysis
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Young, R.C.
1982-04-01
This report discusses the implementation of a finite element program on a Floating Point Systems AP190L array processor attached to a Univac 1182 host computer. The array processor was used to perform all calculations on the global system of linear equations including matrix assembly, matrix factoring and vector solution. A large scratch disk was attached directly to the array processor for storing the factored matrix. The remaining calculations, including data preparation, element matrix formation, stress integration and output display were performed by the host computer.
A pipelined 50-MHz CMOS 64-bit floating-point arithmetic processor
Energy Technology Data Exchange (ETDEWEB)
Benschneider, B.J.; Bowhill, W.J.; Cooper, E.M.; Gronowski, P.E.; Peng, V.; Pickholtz, J.D.; Samudrala, S. (Digital Equipment Corp., Hudson, MA (US)); Gavrielov, M.N. (LSI Logic Corp., Milpitas, CA (US)); Maheshwari, V.K. (AT and T Bell Labs., Allentown, PA (US))
1989-10-01
A 135 K transistor, uniformly pipelined 50-MHz CMOS 64-bit floating-point arithmetic processor chip is described. The execution unit is capable of sustaining pipelined performance of one 32-bit or 64-bit result every 20 ns for all operations except double-precision multiply (40 ns) and divide. The chip employs an exponent difference prediction scheme and a unified leading-one and sticky-bit computation logic for the addition (ADD) and subtraction (SUB) operations. A hardware multiplier using a radix-8 modified Booth algorithm and a divider using a radix-2 SRT algorithm ar used.
A 40-MFLOPS 32-bit floating-point processor with elastic pipeline scheme
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Komori, S.; Takata, H.; Tamura, T.; Asai, F.; Ohno, T.; Tomisawa, O. (LSI Research and Development Lab., Mitsubishi Electric Corp., Itami, Hyogo 664 (JP)); Yamasaki, T.; Shima, K. (Industrial Electronics and Systems Development Lab., Mitsubishi Electric Corp., Hyogo (JP)); Nishikawa, H.; Terada, H. (Osaka Univ., Dept. of Information Systems Engineering, Osaka (JP))
1989-10-01
This paper presents a 40-MFLOPS 32-bit floating-point processor (FP) which is a component chip for a data-driven single-board processor. The FP is the first practical LSI chip which has introduced the elastic pipeline scheme. All parts in the FP are autonomously controlled by self-timed circuits, and no system clock is needed for processing. The elastic pipeline scheme provides data buffering capability and stabilization of circuit operation at the same time. Pipelining has been extensively utilized so that high throughput over 40-MFLOPS can be achieved. An automatic power conservation technique, called latch mode control, is also described.
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Villa, Oreste; Chavarría-Miranda, Daniel; Gurumoorthi, Vidhya; Marquez, Andres; Krishnamoorthy, Sriram
2009-05-03
Floating-point addition and multiplication are not necessarily associative. When performing those operations over large numbers of operands with different magnitudes, the order in which individual operations are performed can affect the final result. On massively multithreaded systems, when performing parallel reductions, the non-deterministic nature of numerical operation interleaving can lead to non-deterministic numerical results. We have investigated the effect of this problem on the convergence of a conjugate gradient calculation used as part of a power grid analysis application.
Directory of Open Access Journals (Sweden)
Malte Baesler
2013-01-01
and decimal formats, for instance, commercial, financial, and insurance applications. In this paper we present five different radix-10 digit recurrence dividers for FPGA architectures. The first one implements a simple restoring shift-and-subtract algorithm, whereas each of the other four implementations performs a nonrestoring digit recurrence algorithm with signed-digit redundant quotient calculation and carry-save representation of the residuals. More precisely, the quotient digit selection function of the second divider is implemented fully by means of a ROM, the quotient digit selection function of the third and fourth dividers are based on carry-propagate adders, and the fifth divider decomposes each digit into three components and requires neither a ROM nor a multiplexer. Furthermore, the fixed-point divider is extended to support IEEE 754-2008 compliant decimal floating-point division for decimal64 data format. Finally, the algorithms have been synthesized on a Xilinx Virtex-5 FPGA, and implementation results are given.
A Vector-Like Reconfigurable Floating-Point Unit for the Logarithm
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Nikolaos Alachiotis
2011-01-01
Full Text Available The use of reconfigurable computing for accelerating floating-point intensive codes is becoming common due to the availability of DSPs in new-generation FPGAs. We present the design of an efficient, pipelined floating-point datapath for calculating the logarithm function on reconfigurable devices. We integrate the datapath into a stand-alone LUT-based (Lookup Table component, the LAU (Logarithm Approximation Unit. We extended the LAU, by integrating two architecturally independent, LAU-based datapaths into a larger component, the VLAU (vector-like LAU. The VLAU produces 2 results/cycle, while occupying the same amount of memory as the LAU. Under single precision, one LAU is 12 and 1.7 times faster than the GNU and Intel Math Kernel Library (MKL implementations, respectively. The LAU is also 1.6 times faster than the FloPoCo reconfigurable logarithm architecture. Under double precision, one LAU is 20 and 2.6 times faster than the respective GNU and MKL functions and 1.4 times faster than the FloPoCo logarithm. The VLAU is approximately twice as fast as the LAU, both under single and double precision.
Percola: a special purpose programmable 64-BIT floating-point processor
Energy Technology Data Exchange (ETDEWEB)
Normand, J.M.
1988-01-01
The computer PERCOLA is designed for lengthy numerical simulations on a percolation problem in Statistical Mechanics of disordered media. The project that the computer is engaged on at present is intended to improve the true values of critical indices characteristic of the behaviour of electrical conductivity at percolation threshold in a system of random resistors. The architecture is based on an efficient highly iterative algorithm to compute the electrical conductivity of random resistor networks. This computer runs programs of percolation problems considered 10 percent faster than the Cray X-MP with the same 64-bit floating-point precision. Operating since May 1987, months of calculation have already been performed. Although best suited to a class of algorithms, the processor includes a powerful 32-bit integer random number generator and has many characteristics of general purpose 64-bit floating-point microprogrammable computers that can run programs for various type of problems with a peak performance of more than 25 Mflops. This high computing speed is not the result of one all-powerful feature, but a balance among several factors including supercomputer derived features such as mainly: concurrent functional units separately controlled from independent microcode fields, distinct buses for data, addresses and instructions, flexible and powerful address generators for matrix processing and an advanced pipeline design implementing high performance VLSI Weitek's and Analog Devices components.
Coded Calculation for Floating Point Values in Safety I and C - Implementation and Experiences
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Arndt, Lindner; Christian, Gerst; Andreas, Molleken [TUV Rheinland ISTec-GmbH, Boltzmannstr (Germany)
2014-08-15
The paper describes a methodology to detect erroneous floating point calculations in digital safety I and C during run time. The methodology has the potential to detect processor failures as well as memory failures. It is based on the extension of the normally used algebra to the complex number plain. In the complex number plain a set of sub-algebras is defined. The sub-algebras are characterized by a subset of valid numbers, the decision criteria for validity of a number and appropriate modified operations (addition, subtraction, multiplication, division). In case of a failure of the processor or the memory, the calculation in any of the sub-algebras will result in complex numbers that are not element of the set of elements of the sub-algebra. This is detected by the given criteria. The theoretical background of the methodology was already presented at the NPIC and HMIT conference in San Diego in 2012. The paper presents the extension of the methodology to logical functions and the implementation in a real I and C platform. The results of practical tests are given. This includes tests of calculation overhead and detection of typical failures. Additionally experiences regarding floating point precision are provided.
Sheehan, J. P.; Raitses, Yevgeny; Hershkowitz, Noah; Fisch, Nathaniel
2010-11-01
Theory suggests that when increasing the electron emission of an emissive probe the floating potential will saturate ˜Te/e below the plasma potential. This can introduce significant errors in plasma potential measurements in Hall thrusters where Te> 10 eV. The method of determining the plasma potential from the inflection point of emissive IV traces in the limit of zero emission may give a more accurate measurement of the plasma potential. The two methods are compared in a Hall thruster where ne˜10^11 cm-3, Te˜20 eV, and ion flows are significant. The results can be generalized to other types of plasmas.
High-performance Floating-point to Fixed-point Translation Strategy%浮点到定点的高效翻译策略研究
Institute of Scientific and Technical Information of China (English)
郑重; 陈顼颢; 沈立; 王志英
2011-01-01
When doing dynamic binary translation, if no floating-point component exists in the target platform so that it does not support floating-point operations, floating-point instructions can only be interpreted through simulation.Interpretation of floating-point instruction causes a sharp translation efficiency decrease.This article addresses a method that translating floating-point operations into fixed-point operations, which gives a new way to solve floating-point instruction translation in the no-floating target platform.Implementation of this method in a dynamic binary translation system proves the feasibility of the translation algorithm.The experiment also shows significantly the improvement of performance and the higher the proportion of floating-point instruction, the higher the speedup.And the speedup is up to 1.55 when the binary code contains 25％ floating-point instructions.%动态二进制翻译中,在目标平台没有浮点部件、不支持浮点运算的情况下,浮点指令只能通过模拟解释执行.浮点指令的解释执行造成翻译系统效率急剧下降.通过将浮点指令运算转化为定点运算,解决了浮点指令在目标平台的翻译,为浮点指令的翻译找到了新的途径.在动态二进制翻译系统中进行实验,验证了翻译方法的可行性.实验显示翻译系统的性能有明显提升,含有浮点指令的比例越高,算法能够获得的加速比越高,对含有25%浮点指令的程序,该算法能达到1.55的加速比.
Quantifying the Impact of Single Bit Flips on Floating Point Arithmetic
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Elliott, James J [ORNL; Mueller, Frank [North Carolina State University; Stoyanov, Miroslav K [ORNL; Webster, Clayton G [ORNL
2013-08-01
In high-end computing, the collective surface area, smaller fabrication sizes, and increasing density of components have led to an increase in the number of observed bit flips. If mechanisms are not in place to detect them, such flips produce silent errors, i.e. the code returns a result that deviates from the desired solution by more than the allowed tolerance and the discrepancy cannot be distinguished from the standard numerical error associated with the algorithm. These phenomena are believed to occur more frequently in DRAM, but logic gates, arithmetic units, and other circuits are also susceptible to bit flips. Previous work has focused on algorithmic techniques for detecting and correcting bit flips in specific data structures, however, they suffer from lack of generality and often times cannot be implemented in heterogeneous computing environment. Our work takes a novel approach to this problem. We focus on quantifying the impact of a single bit flip on specific floating-point operations. We analyze the error induced by flipping specific bits in the most widely used IEEE floating-point representation in an architecture-agnostic manner, i.e., without requiring proprietary information such as bit flip rates and the vendor-specific circuit designs. We initially study dot products of vectors and demonstrate that not all bit flips create a large error and, more importantly, expected value of the relative magnitude of the error is very sensitive on the bit pattern of the binary representation of the exponent, which strongly depends on scaling. Our results are derived analytically and then verified experimentally with Monte Carlo sampling of random vectors. Furthermore, we consider the natural resilience properties of solvers based on the fixed point iteration and we demonstrate how the resilience of the Jacobi method for linear equations can be significantly improved by rescaling the associated matrix.
FLOS-1R and FLOD-1R Single- and Double-Precision Floating Point Packages for the LINC,
floating point package for the LINC. The present revision corrects an error in the Add routine, requires fewer memory locations, and is slightly faster than the original program. The functional description of Flod-1R is exactly identical to that of the original program FLOD. Since the original report also described a matching single-precision floating point package, FLOS, the report also describes FLOS. Although FLOS has not been revised, it is given the revised name FLOS-1R in this report. (Modified author
High-Precision Floating-Point Arithmetic in ScientificComputation
Energy Technology Data Exchange (ETDEWEB)
Bailey, David H.
2004-12-31
At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required: some of these applications require roughly twice this level; others require four times; while still others require hundreds or more digits to obtain numerically meaningful results. Such calculations have been facilitated by new high-precision software packages that include high-level language translation modules to minimize the conversion effort. These activities have yielded a number of interesting new scientific results in fields as diverse as quantum theory, climate modeling and experimental mathematics, a few of which are described in this article. Such developments suggest that in the future, the numeric precision used for a scientific computation may be as important to the program design as are the algorithms and data structures.
Optimal Compression of Floating-point Astronomical Images Without Significant Loss of Information
Pence, W D; Seaman, R
2010-01-01
We describe a compression method for floating-point astronomical images that gives compression ratios of 6 -- 10 while still preserving the scientifically important information in the image. The pixel values are first preprocessed by quantizing them into scaled integer intensity levels, which removes some of the uncompressible noise in the image. The integers are then losslessly compressed using the fast and efficient Rice algorithm and stored in a portable FITS format file. Quantizing an image more coarsely gives greater image compression, but it also increases the noise and degrades the precision of the photometric and astrometric measurements in the quantized image. Dithering the pixel values during the quantization process can greatly improve the precision of measurements in the images. This is especially important if the analysis algorithm relies on the mode or the median which would be similarly quantized if the pixel values are not dithered. We perform a series of experiments on both synthetic and real...
FloPSy - Search-Based Floating Point Constraint Solving for Symbolic Execution
Lakhotia, Kiran; Tillmann, Nikolai; Harman, Mark; de Halleux, Jonathan
Recently there has been an upsurge of interest in both, Search-Based Software Testing (SBST), and Dynamic Symbolic Execution (DSE). Each of these two approaches has complementary strengths and weaknesses, making it a natural choice to explore the degree to which the strengths of one can be exploited to offset the weakness of the other. This paper introduces an augmented version of DSE that uses a SBST-based approach to handling floating point computations, which are known to be problematic for vanilla DSE. The approach has been implemented as a plug in for the Microsoft Pex DSE testing tool. The paper presents results from both, standard evaluation benchmarks, and two open source programs.
Full floating point vector processor with dynamically configurable multifunction pipelined ALU
Energy Technology Data Exchange (ETDEWEB)
Porter, J.B.; Altmann, D.W.; Mattedi, B.A.; Jones, R.
1986-05-13
A full floating point vector processor is described which consists of: a master processing unit; an input and an output bus for providing a plurality of addressable memory locations; a means for loading data to be evaluated in the addressable memory locations; a means for providing a plurality of time sequential memory read and write addresses, and for providing a selectively delayed control signal; a means for providing a plurality of time sequential microinstructions in time-synchronization with corresponding ones of the plurality of time sequential memory read and write addresses; and a means for evaluating in accordance with the synchronously applied microinstructions one of a preselected computationally intensive functions on the data on the output bus and for providing a data value on the input bus representative of the evaluation of the selected one of the computationally intensive functions.
Quantum chemical calculations using the Floating Point Systems, Inc. Model 164 attached processor
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Shepard, R.; Bair, R.A.; Eades, R.A.; Wagner, A.F.; Davis, M.J.; Harding, L.B.; Dunning, T.H. Jr.
1983-01-01
The Theoretical Chemistry Group at Argonne National Laboratory has had a Floating Point System, Inc., Model 164 Attached Processor (FPS-164) for several months. Actual production calculations, as well as benchmark calculations, indicate that the FPS-164 is capable of performance comparable to large mainframe computers, the groups experience with the FPS-164 includes the conversion of a complete system of electronic structure codes, including integral evaluation programs, generalized valence bond programs, integral transformation programs, and unitary group configuration interaction programs, and two classical trajectory codes. Timings of these programs at various levels of optimization along with estimates of the amount of effort required to make the necessary program modifications are discussed. 10 references, 2 figures, 2 tables.
Real-time IP-hologram conversion hardware based on floating point DSPs
Oi, Ryutaro; Mishina, Tomoyuki; Yamamoto, Kenji; Okui, Makoto
2009-02-01
Holography is a 3-D display method that fully satisfies the visual characteristics of the human eye. However, the hologram must be developed in a darkroom under laser illumination. We attempted hologram generation under white light by adopting an integral photography (IP) technique as the input. In this research, we developed a hardware converter to convert IP input (with 120×66 elemental images) to a hologram with high definition television (HDTV) resolution (approximately 2 million pixels). This conversion could be carried out in real time. In this conversion method, each elemental image can be independently extracted and processed. Our hardware contains twenty 300-MHz floating-point digital signal processors (DSPs) operating in parallel. We verified real-time conversion operations by the implemented hardware.
Comparison between GEOCOR IV SIGN-BIT an DFS-V 16-bit floating point recording systems
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Hollis, D.D.; Givens, R.
1986-04-01
A Vibroseis line was repeatedly shot in Andrews County, Texas. The first shot used a DFS-V 16-bit floating point recording system with parameters optimized for that particular recording system and subsurface geology. Then the line was shot with a GEOCOR IV SIGN-BIT recording system, once using the same parameters as on the floating point recording system, then with parameters optimized for a SIGN-BIT recording system - mainly higher fold, closer channel spacing, and using the VARISWEEP technique. The three lines were processed to stacked sections using identical processing parameters. When the 16-bit floating point recording system is compared to the SIGN-BIT system with identical parameters, the results indicate the systems are equivalent for Vibroseis recording. Basic primary reflections are similar in signal to noise and frequency. Multiple reflection energy is greater on the floating point section. However, the results differ when the two systems are compared using optimal parameters for each system. The SIGN-BIT section had shallower data because the receiver line has no gapping. The SIGN-BIT system also had better temporal and spatial resolution because channel spacing was reduced and a different sweep technique was used.
Design and implementation of floating-point adders%FPU加法器的设计与实现
Institute of Scientific and Technical Information of China (English)
田祎; 颜军
2012-01-01
Floating point adders is the core component of FPU, It＇s the foundation of floating-point operation instruction, To improve the design optimization is very important of floating-point calculation speed and precision. This article from the floating-point adder algorithm and circuit implementation give design method, Through the VHDL language in Quartusii in design and validation ,The adder through the FSM control operations, Effective to reduce the power consumption, Improve the speed and function.%浮点运算器的核心运算部件是浮点加法器，它是实现浮点指令各种运算的基础，其设计优化对于提高浮点运算的速度和精度相当关键。文章从浮点加法器算法和电路实现的角度给出设计方法，通过VHDL语言在QuartusⅡ中进行设计和验证，此加法器通过状态机控制运算，有效地降低了功耗，提高了速度，改善了性能。
Institute of Scientific and Technical Information of China (English)
Prabhu E; Mangalam H; Karthick S
2016-01-01
In this work, power efficient butterfly unit based FFT architecture is presented. The butterfly unit is designed using floating-point fused arithmetic units. The fused arithmetic units include two-term dot product unit and add-subtract unit. In these arithmetic units, operations are performed over complex data values. A modified fused floating-point two-term dot product and an enhanced model for the Radix-4 FFT butterfly unit are proposed. The modified fused two-term dot product is designed using Radix-16 booth multiplier. Radix-16 booth multiplier will reduce the switching activities compared to Radix-8 booth multiplier in existing system and also will reduce the area required. The proposed architecture is implemented efficiently for Radix-4 decimation in time (DIT) FFT butterfly with the two floating-point fused arithmetic units. The proposed enhanced architecture is synthesized, implemented, placed and routed on a FPGA device using Xilinx ISE tool. It is observed that the Radix-4 DIT fused floating-point FFT butterfly requires 50.17% less space and 12.16% reduced power compared to the existing methods and the proposed enhanced model requires 49.82% less space on the FPGA device compared to the proposed design. Also, reduced power consumption is addressed by utilizing the reusability technique, which results in 11.42% of power reduction of the enhanced model compared to the proposed design.
Ahmad, Adeel; Ali, Murtaza; South, Fredrick; Monroy, Guillermo L.; Adie, Steven G.; Shemonski, Nathan; Carney, P. Scott; Boppart, Stephen A.
2013-03-01
The transition of optical coherence tomography (OCT) technology from the lab environment towards the more challenging clinical and point-of-care settings is continuing at a rapid pace. On one hand this translation opens new opportunities and avenues for growth, while on the other hand it also presents a new set of challenges and constraints under which OCT systems have to operate. OCT systems in the clinical environment are not only required to be user friendly and easy to operate, but should also be portable, have a smaller form factor coupled with low cost and reduced power consumption. Digital signal processors (DSP) are in a unique position to satisfy the computational requirements for OCT at a much lower cost and power consumption compared to the existing platforms such as CPU and graphics processing units (GPUs). In this work, we describe the implementation of optical coherence tomography (OCT) and interferometric synthetic aperture microscopy (ISAM) processing on a floating point multi-core DSP (C6678, Texas Instruments). ISAM is a computationally intensive data processing technique that is based on the re-sampling of the Fourier space of the data to yield spatially invariant transverse resolution in OCT. Preliminary results indicate that 2DISAM processing at 70,000 A-lines/sec and OCT at 180,000 A-lines/sec can be achieved with the current implementation using available DSP hardware.
NIOS Custom Instruction on Floating-Point Arithmetic%NIOS浮点运算定制指令的实现
Institute of Scientific and Technical Information of China (English)
陈鹏; 蔡雪梅
2011-01-01
To improve the efficiency of floating-point arithmetic on NIOS system, a module of using Verilog to implement singleprecision floating-point addition. subtraction and multiplication is proposed, and its function in Quartus is verified through waveform simulation. According to the custom instruction feature of NIOS ii, adding this module to SOPC Builder, expanding a new hardwarebased floating-point arithmetic instruction, which can be applied in NIOS IDE. Comparing the output and calculating time between NIOS ii software arithmetic and the new hardware floating-point instructions, the supenority of the hardware instruction computation is verified, and a more efficient choice is provided for NIOS in floating-point arirhmetic.%为提高NIOS系统的浮点计算效率,使用Verilog语言实现了单精度浮点数加减及乘法运算的功能模块,并通过波形验证其功能,依据NIOSⅡ定制指令的制定规范,将这一功能添加到SOPC Builder中,扩展出新的基于硬件电路的浮点运算指令,使之在NIOS软件环境中得到应用.通过NIOSⅡ本身软件浮点计算和新增硬件指令进行运算结果和时间上的对比,证实硬件指令计算的优越性,为NIOS下的浮点运算提供了更有效率的选择.
Institute of Scientific and Technical Information of China (English)
姜加红; 陈立前; 王戟
2013-01-01
浮点变量在程序中的取值范围对浮点程序中相关性质的分析及运行时错误的检查具有重要意义。浮点运算的不精确性使得浮点变量的值范围分析具有挑战性。抽象解释理论为程序变量的值范围分析提供了一个通用的框架。在抽象解释的框架下，提出了一个新的数值抽象域——区间幂集抽象域，即使用有限个区间的析取来刻画变量的取值范围。该抽象域的表达能力强于经典的区间抽象域，能够较好地刻画大部分已有抽象域不能表达的非凸性质，从而有效提高分析精度。在此基础上，给出了区间幂集抽象域的可靠浮点实现方法，阐述了如何应用基于该抽象域的浮点实现对浮点程序进行可靠分析。基于抽象解释框架，设计实现了一个面向浮点C程序的静态分析工具原型，并使用浮点实现的区间幂集抽象域对一些浮点程序进行分析。%The value range of floating-point variables in the program is very important for analyzing properties and finding run-time errors in floating-point programs. The inexactness of floating-point computation makes it challenging to analyze value range of floating-point variables. The theory of interpretation provides a general framework to analyze the value range of program variables. Under this framework, this paper proposes a new numerical domain, namely powerset of intervals domain, which uses disjunctions of finite numbers of intervals to express the value range of a variable. It is more expressive than the classic interval domain, and can infer some non-convex properties that are beyond the ability of most numerical domains. On this basis, this paper gives a sound floating-point implementation for the new domain, and shows how to analyze floating-point programs soundly using this domain. Finally, this paper implements a static analyzer prototype for analyzing floating-point C programs based on the
MCS-8 floating point package user's manual (15 Oct 1974) (Engineering Materials). [Text (9 pages)
Energy Technology Data Exchange (ETDEWEB)
Seven subroutines for decimal point control in computer calculations are described. The internal registers are used as pointers to operands. In each case, the pointer must be set to the first word in the word sequence of an operand. A concise description is given of the Floating Point routines, the use of internal registers, and the use of the mantissa sign and exponent sign. (PMA)
A Heuristic Scheduler for Port-Constrained Floating-Point Pipelines
Directory of Open Access Journals (Sweden)
Zheming Jin
2013-01-01
Full Text Available We describe a heuristic scheduling approach for optimizing floating-point pipelines subject to input port constraints. The objective of our technique is to maximize functional unit reuse while minimizing the following performance metrics in the generated circuit: (1 maximum multiplexer fanin, (2 datapath fanout, (3 number of multiplexers, and (4 number of registers. For a set of systems biology markup language (SBML benchmark expressions, we compare the resource usages given by our method to those given by a branch-and-bound enumeration of all valid schedules. Compared with the enumeration results, our heuristic requires on average 33.4% less multiplexer bits and 32.9% less register bits than the worse case, while only requiring 14% more multiplexer bits and 4.5% more register bits than the optimal case. We also compare our results against those given by the state-of-art high-level synthesis tool Xilinx AutoESL. For the most complex of our benchmark expressions, our synthesis technique requires 20% less FPGA slices than AutoESL.
Verification of Numerical Programs: From Real Numbers to Floating Point Numbers
Goodloe, Alwyn E.; Munoz, Cesar; Kirchner, Florent; Correnson, Loiec
2013-01-01
Numerical algorithms lie at the heart of many safety-critical aerospace systems. The complexity and hybrid nature of these systems often requires the use of interactive theorem provers to verify that these algorithms are logically correct. Usually, proofs involving numerical computations are conducted in the infinitely precise realm of the field of real numbers. However, numerical computations in these algorithms are often implemented using floating point numbers. The use of a finite representation of real numbers introduces uncertainties as to whether the properties veri ed in the theoretical setting hold in practice. This short paper describes work in progress aimed at addressing these concerns. Given a formally proven algorithm, written in the Program Verification System (PVS), the Frama-C suite of tools is used to identify sufficient conditions and verify that under such conditions the rounding errors arising in a C implementation of the algorithm do not affect its correctness. The technique is illustrated using an algorithm for detecting loss of separation among aircraft.
The quantitative analysis of instantaneous floating-point amplifier in DFS-V seismic system
Energy Technology Data Exchange (ETDEWEB)
Xianiu, H.; Wenze, Y.; Yanyun, D.; Qi, F.
1988-01-01
On the basis of analysing the principle and circuit of instantaneous floating-point amplifier (IFP amplifier) in DFS-V seismic system, the authors developed a set of mathematic models for quantitative analysis of IFP amplifier, and designed the program for computing and plotting. The amplitude characteristic curves were computed and plotted on DUAL-6800 microcomputer by making use of the original parameters of DFS-V seismic system. The computation result shows that this system can effectively restrain the overflow distortion caused by zero-passage dipping-top sample to make high fidelity transmission of seismic signals, but its measurement accuracy is on the low side. In order to overcome the demerit, the authors changed the original parameters of IFP amplifier circuit and made a great deal of sweep computation, so that they found these ideal new parameters: prediction time(c) = 3..mu..s, upper reference level(V) = 6.8V and 7.2V, lower reference level(V) = 1.6V and 1.7V. As a result, no overflow distortion occurs, furthermore IFP amplifier shows much higher measurement accuracy than before, these favour the ameliorating of seismic signals.
Kole, J. S.; Beekman, F. J.
2006-02-01
Statistical reconstruction methods offer possibilities to improve image quality as compared with analytical methods, but current reconstruction times prohibit routine application in clinical and micro-CT. In particular, for cone-beam x-ray CT, the use of graphics hardware has been proposed to accelerate the forward and back-projection operations, in order to reduce reconstruction times. In the past, wide application of this texture hardware mapping approach was hampered owing to limited intrinsic accuracy. Recently, however, floating point precision has become available in the latest generation commodity graphics cards. In this paper, we utilize this feature to construct a graphics hardware accelerated version of the ordered subset convex reconstruction algorithm. The aims of this paper are (i) to study the impact of using graphics hardware acceleration for statistical reconstruction on the reconstructed image accuracy and (ii) to measure the speed increase one can obtain by using graphics hardware acceleration. We compare the unaccelerated algorithm with the graphics hardware accelerated version, and for the latter we consider two different interpolation techniques. A simulation study of a micro-CT scanner with a mathematical phantom shows that at almost preserved reconstructed image accuracy, speed-ups of a factor 40 to 222 can be achieved, compared with the unaccelerated algorithm, and depending on the phantom and detector sizes. Reconstruction from physical phantom data reconfirms the usability of the accelerated algorithm for practical cases.
Energy Technology Data Exchange (ETDEWEB)
Kole, J S; Beekman, F J [Image Sciences Institute, Department of Nuclear Medicine and Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, UMC Utrecht, Universiteitsweg 100, STR5.203, 3584 CG Utrecht (Netherlands)
2006-02-21
Statistical reconstruction methods offer possibilities to improve image quality as compared with analytical methods, but current reconstruction times prohibit routine application in clinical and micro-CT. In particular, for cone-beam x-ray CT, the use of graphics hardware has been proposed to accelerate the forward and back-projection operations, in order to reduce reconstruction times. In the past, wide application of this texture hardware mapping approach was hampered owing to limited intrinsic accuracy. Recently, however, floating point precision has become available in the latest generation commodity graphics cards. In this paper, we utilize this feature to construct a graphics hardware accelerated version of the ordered subset convex reconstruction algorithm. The aims of this paper are (i) to study the impact of using graphics hardware acceleration for statistical reconstruction on the reconstructed image accuracy and (ii) to measure the speed increase one can obtain by using graphics hardware acceleration. We compare the unaccelerated algorithm with the graphics hardware accelerated version, and for the latter we consider two different interpolation techniques. A simulation study of a micro-CT scanner with a mathematical phantom shows that at almost preserved reconstructed image accuracy, speed-ups of a factor 40 to 222 can be achieved, compared with the unaccelerated algorithm, and depending on the phantom and detector sizes. Reconstruction from physical phantom data reconfirms the usability of the accelerated algorithm for practical cases.
Combinatorial floating point processor as an integral part of the computer
Energy Technology Data Exchange (ETDEWEB)
Undheim, T.
1980-01-01
This paper describes the Nord-500 which is a dual computer system consisting of a Nord-500 CPU, a Nord-100 CPU and a multiport memory. The Nord-500 CPU executes large time-consuming user programs. The Nord-100 minicomputer acts as a system supervisor for the Nord-500. The Nord-100 runs the multi-mode, multi-user Sintran III/VS operating system and performs all input/output handling, job scheduling and resource allocations. The Nord-100 leaves the Nord-500 CPU free to run user programs with a minimum of system overhead. Up to 64 users can access the system in real-time, time-sharing and batch mode, and share up to 32 mbytes of fast MOS memory and 2300 mbytes of disk storage, and a variety of other peripherals. The basic time of 200 ns executes the majority of the Nord-500's machine instructions. Several Nord-500 processors, with hardware array logic for 32/64 bit floating point multiply/divide, can act as a multiprocessor system supervised by a Nord-100.
Optimal Compression of Floating-Point Astronomical Images Without Significant Loss of Information
Pence, William D.; White, R. L.; Seaman, R.
2010-01-01
We describe a compression method for floating-point astronomical images that gives compression ratios of 6 - 10 while still preserving the scientifically important information in the image. The pixel values are first preprocessed by quantizing them into scaled integer intensity levels, which removes some of the uncompressible noise in the image. The integers are then losslessly compressed using the fast and efficient Rice algorithm and stored in a portable FITS format file. Quantizing an image more coarsely gives greater image compression, but it also increases the noise and degrades the precision of the photometric and astrometric measurements in the quantized image. Dithering the pixel values during the quantization process greatly improves the precision of measurements in the more coarsely quantized images. We perform a series of experiments on both synthetic and real astronomical CCD images to quantitatively demonstrate that the magnitudes and positions of stars in the quantized images can be measured with the predicted amount of precision. In order to encourage wider use of these image compression methods, we have made available a pair of general-purpose image compression programs, called fpack and funpack, which can be used to compress any FITS format image.
Directory of Open Access Journals (Sweden)
Urriza I
2010-01-01
Full Text Available Abstract This paper presents a word length selection method for the implementation of digital controllers in both fixed-point and floating-point hardware on FPGAs. This method uses the new types defined in the VHDL-2008 fixed-point and floating-point packages. These packages allow customizing the word length of fixed and floating point representations and shorten the design cycle simplifying the design of arithmetic operations. The method performs bit-true simulations in order to determine the word length to represent the constant coefficients and the internal signals of the digital controller while maintaining the control system specifications. A mixed-signal simulation tool is used to simulate the closed loop system as a whole in order to analyze the impact of the quantization effects and loop delays on the control system performance. The method is applied to implement a digital controller for a switching power converter. The digital circuit is implemented on an FPGA, and the simulations are experimentally verified.
Energy Technology Data Exchange (ETDEWEB)
Meinicke, G.; Loeb, E.; M' Seddi, A.
1979-11-01
The development of a floating point convolver and its integration into a computer system for the processing of seismic data inevitably resulted in the development of an efficient Array Processor System (APS). The total project of a small efficient seismic processing system SSP-11 A with the host computer PDP 11/45 with integrated APS can be considered as a successful one. Seismic processes are carried out in floating point format by the APS and, thus, the basis for the Real Amplitude Processing is provided. Moreover, the efficiency of the system SSP-11 A, in the relation to SSP-11, can be doubled, with regard to the throughput of seismic data. Thus, in the new system SSP-11 A capacity for more sophisticated seismic programs is available. For decentralized operation the SSP-11 A is, as a minicomputer system, a real economical alternative to large computer systems. 7 figures.
Directory of Open Access Journals (Sweden)
Hasitha Muthumala Waidyasooriya
2014-01-01
Full Text Available Acceleration of FDTD (finite-difference time-domain is very important for the fields such as computational electromagnetic simulation. We consider the FDTD simulation model of cylindrical resonator design that requires double precision floating-point and cannot be done using single precision. Conventional FDTD acceleration methods have a common problem of memory-bandwidth limitation due to the large amount of parallel data access. To overcome this problem, we propose a hybrid of single and double precision floating-point computation method that reduces the data-transfer amount. We analyze the characteristics of the FDTD simulation to find out when we can use single precision instead of double precision. According to the experimental results, we achieved over 15 times of speed-up compared to the CPU single-core implementation and over 1.52 times of speed-up compared to the conventional GPU-based implementation.
Creditability in ALU of floating-point%浮点运算部件中可信性的研究
Institute of Scientific and Technical Information of China (English)
张伟; 韩改宁; 梁新月
2012-01-01
介绍了信息系统可信性的概念,选用了IBM POWER6浮点乘加部件中的算术运算为实例,对提高浮点运算部件中计算可信性的关键技术进行探究,为研究计算机算术运算的可信性提供了一定的参考.%This paper introduces the credibility of information system, and takes the floating point arithmetic operations on IBM P0WER6 for example, provided the key technology in floating point calculation to improve the credibility, which provides a certain reference for study the credibility of the computer arithmetic operations.
Fukushima, Toshio
2012-04-01
By extending the exponent of floating point numbers with an additional integer as the power index of a large radix, we compute fully normalized associated Legendre functions (ALF) by recursion without underflow problem. The new method enables us to evaluate ALFs of extremely high degree as 232 = 4,294,967,296, which corresponds to around 1 cm resolution on the Earth's surface. By limiting the application of exponent extension to a few working variables in the recursion, choosing a suitable large power of 2 as the radix, and embedding the contents of the basic arithmetic procedure of floating point numbers with the exponent extension directly in the program computing the recurrence formulas, we achieve the evaluation of ALFs in the double-precision environment at the cost of around 10% increase in computational time per single ALF. This formulation realizes meaningful execution of the spherical harmonic synthesis and/or analysis of arbitrary degree and order.
Formal Verification of an Iterative Low-Power x86 Floating-Point Multiplier with Redundant Feedback
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Peter-Michael Seidel
2011-10-01
Full Text Available We present the formal verification of a low-power x86 floating-point multiplier. The multiplier operates iteratively and feeds back intermediate results in redundant representation. It supports x87 and SSE instructions in various precisions and can block the issuing of new instructions. The design has been optimized for low-power operation and has not been constrained by the formal verification effort. Additional improvements for the implementation were identified through formal verification. The formal verification of the design also incorporates the implementation of clock-gating and control logic. The core of the verification effort was based on ACL2 theorem proving. Additionally, model checking has been used to verify some properties of the floating-point scheduler that are relevant for the correct operation of the unit.
Formal Verification of an Iterative Low-Power x86 Floating-Point Multiplier with Redundant Feedback
Seidel, Peter-Michael
2011-01-01
We present the formal verification of a low-power x86 floating-point multiplier. The multiplier operates iteratively and feeds back intermediate results in redundant representation. It supports x87 and SSE instructions in various precisions and can block the issuing of new instructions. The design has been optimized for low-power operation and has not been constrained by the formal verification effort. Additional improvements for the implementation were identified through formal verification. The formal verification of the design also incorporates the implementation of clock-gating and control logic. The core of the verification effort was based on ACL2 theorem proving. Additionally, model checking has been used to verify some properties of the floating-point scheduler that are relevant for the correct operation of the unit.
Energy Technology Data Exchange (ETDEWEB)
Rudy, T.E.
1977-08-01
An alternative to maxi computers for high-speed floating-point processing capabilities is the coupling of a host computer to a programable array processor. This paper compares the performance of two finite difference programs on various computers and their expected performance on commercially available array processors. The significance of balancing array processor computation, host-array processor control traffic, and data transfer operations is emphasized. 3 figures, 1 table.
Pan, Jing; Levitt, Karl N.; Cohen, Gerald C.
1991-01-01
Discussed here is work to formally specify and verify a floating point coprocessor based on the MC68881. The HOL verification system developed at Cambridge University was used. The coprocessor consists of two independent units: the bus interface unit used to communicate with the cpu and the arithmetic processing unit used to perform the actual calculation. Reasoning about the interaction and synchronization among processes using higher order logic is demonstrated.
Energy Technology Data Exchange (ETDEWEB)
Yu, T.L.; Ribbens, W.B.
1991-09-01
The report details the design of a floating-point coprocessor intended for real-time fault detection in electronically controlled internal combustion engines. The fault detection strategies are based on dynamic models of various engine subsystems and require the use of state estimators. The coprocessor can be operated at a clock rate of 24 MHz, and is capable of operating up to sixteen state estimators in real time. The design is suitable for application to internal combustion engines used for vehicle propulsion or power generation, whether diesel or spark ignited.
Udriot, Stève; Bourotte, Jean; Hansen, Magnus; Löfstedt, B
2002-01-01
The Floating Point Preamplifier of the Very Front End Electronics for the CMS Electromagnetic Calorimeter has been investigated on a 5x6 crystal prototype matrix. Discontinuities at the signal peak were observed in the pulse shape reconstruction from the 40MHz sampled and digitized data. The propositions linked to those observations are described, together with a focalized overview of the detector readout chain. A settling time problem is identified and it is shown that a 5ns delay applied to the ADC clock provides a secure solution. Finally, the implementation in the FPPA design of this delay is presented.
Directory of Open Access Journals (Sweden)
Rozita Teymourzadeh
2010-01-01
Full Text Available Problem statement: Fast Fourier Transform (FFT is widely applied in OFDM trance-receiver communications system. Hence efficient FFT algorithm is always considered. Approach: This study proposed FPGA realization of high resolution high speed low latency floating point adder/subtractor for FFT in OFDM trance-receiver. The design was implemented for 32 bit pipelined adder/subtractor which satisfied IEEE-754 standard for floating-point arithmetic. The design was focused on the trade-off between the latency and speed improvement as well as resolution and silicon area for the chip implementation. In order to reduce the critical path and decrease the latency, the novel structure was designed and investigated. Results: Consequently, synthesis report indicated the latency of 4 clock cycles due to each stage operated within just one clock cycle. The unique structure of designed adder well thought out resulted 6691 equivalent gate count and lead us to obtain low area on chip. Conclusion: The synthesis Xilinx ISE software provided results representing the estimated area and delay for design when it is pipelined to various depths. The report showed the minimum delay of 3.592 ns or maximum frequency of 278.42 MHz.
Fukushima, Toshio
2014-02-01
The integrals of fully normalized associated Legendre function (fnALF) of extremely high degree and order such as 223=8 388 608 can be obtained without underflow problems if the point values of fnALF are properly given by using an exponent extension of the floating point numbers (Fukushima, T., 2012a. J. Geod., 86, 271-285; Fukushima, T., 2012c. J. Geod., 86, 1019-1028). A dynamic termination of the exponent extension during the fixed-order increasing-degree recursions significantly reduces the increase in CPU time caused by the exponent extension. Also, the sectorial integrals are found to be correctly obtained by the forward recursion only even when the backward recursion has been claimed to be necessary (Paul, M.K., 1978, Bull. Geod., 52, 177-190; Gerstl, M., 1980, Manuscr. Geod., 5, 181-199).
Energy Technology Data Exchange (ETDEWEB)
Rodriguez, Francisco J.; Cobreces, Santiago; Bueno, Emilio J.; Hernandez, Alvaro; Mateos, Raul; Espinosa, Felipe [Department of Electronics, University of Alcala, Alcala de Henares, Madrid (Spain)
2008-09-15
Modern energy concepts as Distributed Power Generation are changing the appearance of electric distribution and transmission and challenging power electronics researchers, which try to develop new solutions of electronic controllers. The aim is to enable the implementation of new and more complex control algorithms to verify the last standards related to the grid energy quality for new power converters, and, also, for equipments which nowadays are operating. This paper presents the design, implementation and test of a novel real-time controller for a Neutral Point Clamped (NPC) (three-level) multilevel converter based on a floating-point Digital Signal Processor (DSP) and on a Field-Programmable Gate Array (FPGA), by operating in a cooperative way. Although the proposed system can be readily applied to any power electronic application, in this work, it is focused on the next system: a 150 kVA back-to-back three-level NPC Voltage Source Converter (VSC) for wind power applications. (author)
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Shaeffer, D.L.; Kimbrough, J.R.; Denton, S.M.; Kaschimitter, J.L.; Wilburn, J.W.; Davis, R.W.; Colella, N.J. (Lawrence Livermore National Lab., CA (United States)); Holtkamp, D.B. (Los Alamos National Lab., NM (United States))
1991-08-15
Single event upset (SEU) cross sections and total dose hardness of commercially available MIPS R3000 microprocessors (CPU) and R3010 floating point units (FPU) were obtained by exposing these parts to 256 MeV protons from the linear accelerator (LINAC) at the Los Alamos Meson Physics Facility (LAMPF). Parts from several manufacturers were tested. The CPUs and FPUs were tested dynamically during radiation exposure with specially designed assembly language codes which exercised a subset of the available instructions in order to simulate the actual operation of each part. Cross sections derived from the SEU data were used to calculate expected upset rate for a 500-km orbit during quiet solar conditions, the King 1972 solar flare, and the August 4, 1972, event modeled by Adams et al. 16 refs., 16 figs., 3 tabs.
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Morrison, R.E.; Robinson, S.H.
1991-01-01
A continuous wave Doppler radar system has been designed which is portable, easily deployed, and remotely controlled. The heart of this system is a DSP/control board using Analog Devices ADSP-21020 40-bit floating point digital signal processor (DSP) microprocessor. Two 18-bit audio A/D converters provide digital input to the DSP/controller board for near real time target detection. Program memory for the DSP is dual ported with an Intel 87C51 microcontroller allowing DSP code to be up-loaded or down-loaded from a central controlling computer. The 87C51 provides overall system control for the remote radar and includes a time-of-day/day-of-year real time clock, system identification (ID) switches, and input/output (I/O) expansion by an Intel 82C55 I/O expander. 5 refs., 8 figs., 2 tabs.
Energy Technology Data Exchange (ETDEWEB)
Robinson, S.H.; Morrison, R.E.
1991-08-26
A continuous wave doppler radar system has been designed which is portable, easily deployable and can be remotely controlled. The system is immune to ground clutter and is used for wind speed detection and direction determination. Nearly real time digital signal processing is performed by an Analog Devices ADSP-21020, a 40-bit floating point Digital Signal Processing (DSP) microprocessor. This paper provides an overview of the design of the system including the radio frequency (RF) to digital interface. The various DSP detection algorithms are discussed and compared to system performance and sensitivity. Finally, DSP performance is compared to the performance of an earlier system using Analog Device's ADSP-2100. 6 refs.
Energy Technology Data Exchange (ETDEWEB)
Shaeffer, D.L.; Kimbrough, J.R.; Denton, S.M.; Kaschmiter, J.L.; Wilburn, J.W.; Davis, R.W.; Colella, N.J. (Lawrence Livermore National Lab., CA (United States)); Holtkamp, D.B. (Los Alamos National Lab., NM (United States))
1991-12-01
This paper reports on proton single event upset (SEU) cross sections and proton total dose hardness of commercially available MIPS R3000 microprocessors (CPU) and R3010 floating point units (FPU) that were obtained by exposing these parts to 256 MeV protons from the linear accelerator (LINAC) at the Los Alamos Meson Physics Facility (LAMPF). Parts from several manufacturers were tested. The CPUs and FPUs were tested dynamically during radiation exposure with specially designed assembly language codes which exercised a subset of the available instructions. Cross sections derived from the SEU data were used to calculate expected upset rates for a 500-km, 60-degree inclination, orbit during quiet solar conditions and during the August 4, 1972, King solar flare event.
Directory of Open Access Journals (Sweden)
Chi Wai Yu
2008-01-01
Full Text Available This paper examines the interface between fine-grained and coarse-grained programmable logic in FPGAs. Specifically, it presents an empirical study that covers the location, pin arrangement, and interconnect between embedded floating point units (FPUs and the fine-grained logic fabric in FPGAs. It also studies this interface in FPGAs which contain both FPUs and embedded memories. The results show that (1 FPUs should have a square aspect ratio; (2 they should be positioned near the center of the FPGA; (3 their I/O pins should be arranged around all four sides of the FPU; (4 embedded memory should be located between the FPUs; and (5 connecting higher I/O density coarse-grained blocks increases the demand for routing resources. The hybrid FPGAs with embedded memory required 12% wider channels than the case where embedded memory is not used.
Floating point representation denoising mutation on GFMRA%GFMRA的浮点数编码消噪变异
Institute of Scientific and Technical Information of China (English)
崔明义
2014-01-01
MRA是构造小波的重要方法，而GFMRA可以构造任何具有单一母波的正交小波。浮点数编码在函数优化和约束优化领域明显有效于其他编码，但浮点数编码在遗传操作环境中产生的“噪音”严重地影响着遗传算法的性能。在理论分析的基础上，提出基于GFMRA构造的正交小波对浮点数编码消噪变异的FPRGAG方法，并进行了实验。理论研究和实验结果表明，无论是收敛速度还是收敛精度，FPRGAG都远远优于传统算法。该方法理论上是可靠的，技术上是可行的。%Multiresolution Analysis(MRA)is an important method of constructing wavelet. Generalized Frame Multire-solution Analysis(GFMRA)can construct any orthonormal wavelet based on single mother function. Floating Point Representation(FPR)is superior to other representation in function optimization and restriction optimization. The noise which FPR brings about influences badly the performance of genetic algorithm in genetic operation environment. This paper is dependent on theoretical analysis. It presents Floating Point Repreaentation Genetic Algorithm (FPRGA) based on GFMRA(FPRGAG). FPRGAG is a method of FPR denoising mutation by orthonormal wavelet. The experiments are made on FPRGAG. The results of the theoretical research and the experiments indicate FPRGAG is superior to other used algorithms, in convergence efficiency and precision. The method is reliable in theory, is feasible in technique.
A Generic Data Type: the Decimal Floating Point Data%一种通用的数据类型 ——十进制浮点数
Institute of Scientific and Technical Information of China (English)
黄惠生
2001-01-01
为智能仪表提供一种"十进制浮点数"，其特点是值域宽、值准确，它能代替整型、长整型、三字节浮点数、四字节浮点数、BCD码数。用它通信可简化和统一仪表的通信协议，为制定仪表通用通信协议标准创造条件。%A decimal floating point data type is stated for intelligent instruents. Its features include wide value domain and high precision. It can replace integral, long integral, three-byte floating point data, four-byte floating data and BCD code data. The communication can be simplified and the protocol can be uniformed by using this data type. Thus it creates the basis for drawing up the generic commication protocol.
Energy Technology Data Exchange (ETDEWEB)
Scriber, M.W.
1989-12-01
The laser programmable floating point application specific processor (LPASP) is a new approach at rapid development of custom VLSI chips. The LPASP is a generic application specific processor that can be programmed to perform a specific function. The effort of this thesis is to develop and test the double precision floating point adder and the laser programmable read-only memory (LPROM) that are macrocells within the LPASP. In addition, the thesis analyzes the applicability of an LPASP parallel processing system. The double precision floating point adder is an adder/subtractor macrocell designed to comply with the IEEE double precision floating point standard. An 84-pin chip of the adder was fabricated using 2 micron feature sizes. The fastest processing time was measured at 120 nanoseconds over 23 worst case test vectors. The adder uses the optimized carry multiplexed (OCM) adder that was developed at AFIT. The OCM adder is a new adder architecture that uses four parallel carry paths to attain a performance time on the order of (cubed root of M) with a gate count on the order of O (n). The redundant logic associated with the parallel propagation banks is eliminated in the OCM adder so that the largest bit-slice of the adder contains only eight 2-to-1 multiplexer gates. A 57-bit adder was fabricated using 2 micron feature sizes. The processing time for the adder is 31 nsec.
基于FPGA的浮点向量协处理器设计%Design of Floating-point Vector Coprocessor Based on FPGA
Institute of Scientific and Technical Information of China (English)
韩正飞; 李劲松; 潘红兵; 李丽; 沙金; 何书专
2012-01-01
为满足现代数字信号处理中大量数据的运算需求,利用ARM946和Xilinx公司的现场可编程门阵列芯片 逻辑资源和IP库,设计专门用于浮点复数向量运算的64位协处理器,对相关浮点运算进行优化,并在硬件仿真平台上进行测试.结果表 明,该协处理器可使浮点复数向量运算性能得到大幅提高.%To meet the requirement of a series of complex data processing in modern Digital Signal Processor(DSP), a 64 bit floating-point coprocessor specially for floating-point complex vector arithmetic is proposed with the logic resources and IP library of ARM9 and the Field Programmable Gate Array(FPGA) chip from Xilinx. The algorithm of related floating-point arithmetic could be revised. Results of the test on the hardware simulation platform show that the floating-point complex vector arithmetic performance is greatly improved by the coprocessor.
A Floating Point Multiplier based FPGA Synthesis for Neural Networks Enhancement
Directory of Open Access Journals (Sweden)
F. BENREKIA,
2010-05-01
Full Text Available FPGA (Field Programmable Gate Array implementation of Artificial Neural Networks (ANNs calls for multipliers of various word lengths. In this paper, a new approach for designing a FloatingPoint Multiplier(FPM is developed and tested using VHDL. With VHDL (Very High Description Language analyzer and logic synthesis software, hardware prototypes could be implemented in FPGA.
Design of a Floating-point Fixed-point Fused FALU%一种定浮点合并的FALU设计与实现
Institute of Scientific and Technical Information of China (English)
王云贵; 杨靓
2011-01-01
ALU is the key functional unit of modem CPU and DSP. This paper introduced a Floating- point Fixed - point fused FALU, Through combination of functional units reuse technology,operand isolation technology, multiple data path technology, in theory, it can reduce chip area and reduce power consumption effectively. it can execute 21kinds of instruction, Simulation shows that the FALU can function correctly.%算术逻辑单元(ALU)是现代通用处理器和DSP处理器的核心功能部件.设计了一种定浮点合并的FALU,通过结合使用功能单元复用技术、操作数隔离技术和旁路技术,理论上能有效减少芯片的面积,降低芯片的功耗.FALU能实现21种指令,仿真验证显示其功能完全正确.
Homann, Holger; Grauer, Rainer
2007-01-01
In this paper we investigate the impact of the floating-point precision and interpolation scheme on the results of direct numerical simulations (DNS) of turbulence by pseudo-spectral codes. Three different types of floating-point precision configurations show no differences in the statistical results. This implies that single precision computations allow for increased Reynolds numbers due to the reduced amount of memory needed. The interpolation scheme for obtaining velocity values at particle positions has a noticeable impact on the Lagrangian acceleration statistics. A tri-cubic scheme results in a slightly broader acceleration probability density function than a tri-linear scheme. Furthermore the scaling behavior obtained by the cubic interpolation scheme exhibits a tendency towards a slightly increased degree of intermittency compared to the linear one.
On The Dynamics and Design of a Two-body Wave Energy Converter
Liang, Changwei; Zuo, Lei
2016-09-01
A two-body wave energy converter oscillating in heave is studied in this paper. The energy is extracted through the relative motion between the floating and submerged bodies. A linearized model in the frequency domain is adopted to study the dynamics of such a two-body system with consideration of both the viscous damping and the hydrodynamic damping. The closed form solution of the maximum absorption power and corresponding power take-off parameters are obtained. The suboptimal and optimal designs for a two-body system are proposed based on the closed form solution. The physical insight of the optimal design is to have one of the damped natural frequencies of the two body system the same as, or as close as possible to, the excitation frequency. A case study is conducted to investigate the influence of the submerged body on the absorption power of a two-body system subjected to suboptimal and optimal design under regular and irregular wave excitations. It is found that the absorption power of the two-body system can be significantly higher than that of the single body system with the same floating buoy in both regular and irregular waves. In regular waves, it is found that the mass of the submerged body should be designed with an optimal value in order to achieve the maximum absorption power for the given floating buoy. The viscous damping on the submerged body should be as small as possible for a given mass in both regular and irregular waves.
基于IP核的数选式浮点矩阵相乘设计%Floating-point matrix multiplication design based on IP core
Institute of Scientific and Technical Information of China (English)
肖宇; 王建业; 张伟
2011-01-01
Based on the characteristics of a few selected matrix operations, matrix operations with gow-level IP cores, using the number of the IP core embedded in a matrix selection, while floating-point addition operation to add the method to achieve floating-point matrix multiplication. Saving resource consumption while improving system performance, and improved floating-point matrix operations in the FPGA. Simulation results show that the design is feasible, and it has some practical significance and applications.%本文根据数选式矩阵运算特点,结合低阶矩阵运算IP核,采用将IP核嵌入到数选矩阵中,同时添加浮点加法运算的方法,实现浮点矩阵相乘.在节省资源消耗的同时提升了系统性能,并将改进的浮点矩阵运算在FPGA中实现.仿真结果表明该设计可行,具有一定的实际意义和应用前景.
快速浮点运算在FPGA中的实现%Rapid Floating Point Calculations in the Application of FPGA
Institute of Scientific and Technical Information of China (English)
王强
2014-01-01
Floating point calculation is one of important calculations on computers, which is very complex and has certain speed shortcomings for ordinary software. We design the calculation mode by arithmetic of float-point number with single precision under IEEE754 to improve its calculation speed, shorten the period of product development and implement float-point number with single precision in FPGA and making full use of the features of FPGA production line.%浮点计算是计算机计算中的一种重要计算方式，计算过程比较复杂，一般的软件在计算时有一定的速度缺陷。在IEEE754标准下通过FPGA器件对单精度浮点数的四则运算进行运算模块设计，利用FPGA的流水线工作特点，提高浮点计算速度，缩短产品开发周期，在浮点运算的规则下实现了FPGA器件上的单精度浮点数运算。
基于FPGA的高速浮点FFT的实现研究%Research of high speed floating point FFT based on FPGA
Institute of Scientific and Technical Information of China (English)
刘健; 史彩娟; 赵丽莉
2012-01-01
The paper discusses technology of implementing floating point FFr on FPGA. Scheme is given that loop control, RAM access and butterfly operation work together in the way of assembly line. Combined with data buffer and parallel processing technology, working mechanism of butterfly operation is discussed. Floating point multiplier uses structure of parallel Booth encoding and three steps Wallace compression tree, independent fixed point adder and subtractor are used in designing floating point adder, so that operation can be completed in high speed. RAM R/W timing and operation parameters can be setted by register. Design has been implemented by Cyclone-II series chip EP2C8Q208. At 200 MHz, using of external RAM, time of completing 1 024-point complex FFT is only 750 μs.%研究了利用FPGA实现浮点FI叮的技术，提出了一种循环控制、RAM访问和蝶形运算三大模块以流水线方式协同工作的方案，结合数据缓冲和并行处理技术，讨论了蝶形运算单元的工作机制。浮点乘法器采用并行Booth编码和3级Wallace压缩树的结构，浮点加法器中采用独立的定点加法器和减法器，使运算得以高速进行。RAM读／写时序和运算参数都可利用寄存器设置。本设计已在Cyclone-II系列芯片EP2C8Q208中实现，200MHz主频下，采用外部RAM，完成1024点复数FFT只需750μs。
Institute of Scientific and Technical Information of China (English)
胡广垠; 王子欧; 吴升光; 王申卓
2016-01-01
为了对微处理器中浮点运算单元FPU（floating-point unit）进行高效的功能验证，对浮点运算的边界情况进行了研究，引入了对中间结果（intermediate result）的约束解决算法（constriant solved arithmetic）。与传统的对浮点运算单元的功能验证相比，基于该约束算法的浮点数生成器，拓宽了浮点边界情况的可选范围，有效提高了验证效率。实验结果表明，集成该浮点数生成器的UVM验证平台，能够在12小时的测试时间内，对一个浮点运算子模块（floating-point subunit）达到超过99％的覆盖率。%In order to verify the function of the floating-point unit in the microprocessor high-efficiently,numerous corner cases of floating-point arithmetic has been studied.Several arithmetics are introduced to solve the constriants of the intermediate results.Compared with the traditional function verification of floating-point unit,the floating-point number generator based on the constraint solved algorithms has widened the scope of the optional floating-point corner cases,which effectively improves the verification efficiency.Experimental results show that the UVM verification platform which integrated the generator can test one floating-point subunit efficiently,which achieves high coverage beyond 98%,within 12 hours of testing time.
On gravitational interactions between two bodies
Szybka, Sebastian J
2014-01-01
Many physicists, following Einstein, believe that the ultimate aim of theoretical physics is to find a unified theory of all interactions which would not depend on any free dimensionless constant, i.e., a dimensionless constant that is only empirically determinable. We do not know if such a theory exists. Moreover, if it exists, there seems to be no reason for it to be comprehensible for the human mind. On the other hand, as pointed out in Wigner's famous paper, human mathematics is unbelievably successful in natural science. This seeming paradox may be mitigated by assuming that the mathematical structure of physical reality has many `layers'. As time goes by, physicists discover new theories that correspond to the physical reality on the deeper and deeper level. In this essay, I will take a narrow approach and discuss the mathematical structure behind a single physical phenomenon - gravitational interaction between two bodies. The main aim of this essay is to put some recent developments of this topic in a ...
Energy Technology Data Exchange (ETDEWEB)
Vicente, Pedro C.; Falcao, Antonio F. de O.; Gato, Luiz M.C. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal); Justino, Paulo A.P. [Laboratorio Nacional de Energia e Geologia, 1649-038 Lisboa (Portugal)
2009-07-01
It may be convenient that dense arrays of floating point absorbers are spread-moored to the sea bottom through only some of their elements (possibly located in the periphery), while the other array elements are prevented from drifting and colliding with each other by connections to adjacent elements. An array of identical floating point absorbers located at the grid points of an equilateral triangular grid is considered in the paper. A spread set of slack-mooring lines connect the peripheric floaters to the bottom. A weight is located at the centre of each triangle whose function is o pull the three floaters towards each other and keep the inter-body moorings lines under tension. The whole system - buoys, moorings and power take-off systems - is assumed linear, so that a frequency domain analysis may be employed. Hydrodynamic interference between the oscillating bodies is neglected. Equations are presented for a set of three identical point absorbers. This is then extended to more complex equilateral iriangular grid arrays. Results from numerical simulations, with regular and irregular waves, are presented for the motions and power absorption of hemispherical converters in arrays of three and seven elements and different mooring and power take-off parameters, and wave incidence angles. Comparisons are given with the unmoored and independently-moored buoy situations.
High-energy two-body photoproduction
Salin, P
1974-01-01
Considers three aspects of two-body photoproduction reactions: vector meson production as a tool to investigate properties of diffractive reactions; the occurrence of a possible J=0 fixed pole in the Compton amplitude; and pseudoscalar meson photoproduction. (73 refs).
Two-Body Relaxation in Cosmological Simulations
Binney, J; Binney, James; Knebe, Alexander
2002-01-01
The importance of two-body relaxation in cosmological simulations is explored with simulations in which there are two species of particles. The cases of mass ratio sqrt(2):1 and 4:1 are investigated. Simulations are run with both a fixed softening length and adaptive softening using the publicly available codes GADGET and MLAPM, respectively. The effects of two-body relaxation are detected in both the density profiles of halos and the mass function of halos. The effects are more pronounced with a fixed softening length, but even in this case they are not so large as to suggest that results obtained with one mass species are significantly affected by two-body relaxation. The simulations that use adaptive softening are slightly less affected by two-body relaxation and produce slightly higher central densities in the largest halos. They run about three times faster than the simulations that use a fixed softening length.
Directory of Open Access Journals (Sweden)
W. Li
2017-09-01
Full Text Available Recently, laser-scanning technology, especially mobile mapping systems (MMSs, has been applied to measure 3D urban scenes. Thus, it has become possible to simulate a traditional cultural event in a virtual space constructed using measured point clouds. In this paper, we take the festival float procession in the Gion Festival that has a long history in Kyoto City, Japan. The city government plans to revive the original procession route that is narrow and not used at present. For the revival, it is important to know whether a festival float collides with houses, billboards, electric wires or other objects along the original route. Therefore, in this paper, we propose a method for visualizing the collisions of point cloud objects. The advantageous features of our method are (1 a see-through visualization with a correct depth feel that is helpful to robustly determine the collision areas, (2 the ability to visualize areas of high collision risk as well as real collision areas, and (3 the ability to highlight target visualized areas by increasing the point densities there.
Energy Technology Data Exchange (ETDEWEB)
Nascetti, A [Sapienza University of Rome, Scuola di Ingegneria Aerospaziale, Via Salaria 851/881, 00138 Roma (Italy); Valerio, P, E-mail: augusto.nascetti@uniroma1.it [Sapienza University of Rome, Dip. Ingegneria Elettronica, Via Eudossiana 18, 00184, Roma (Italy)
2011-01-15
A readout circuit suitable for multi-channel preamplifiers for pixellated detectors, hybrid detectors or thin film on asic imagers, for applications requiring large dynamic range such as computed tomography is discussed. The circuit implements an asynchronous self-reset with residue conversion scheme combined with a floating point representation of the input current. This solution allows to reach a very high dynamic range with good linearity while ensuring a compact output format. In particular, in the present implementation the input current range extends from 50 fA up to 820 nA corresponding to a 144 dB dynamic range which is equivalent to a 24-bit code. However the proposed scheme only uses 16 output bits for the floating point representation with 12-bit constant relative resolution: 12 bits serve for the output value itself and 4 for storing the position of the transition point between integer and fractional part. In addition, an analytical study of the achievable imaging performances shows that no significant degradation of the SNR is expected for the 12-bit constant relative resolution implementation with respect to the full 24-bit resolution scheme. Finally, the main building blocks of the circuit are analyzed in detail and their characteristics are put in relationship with the overall system performances.
单精度浮点运算单元的FPGA设计与实现%Design and Implement of Single Precision Floating-Point Unit on FPGA
Institute of Scientific and Technical Information of China (English)
张素萍; 李红刚; 张慧坚; 董定超
2011-01-01
This paper analyzes the principle and operation process of the floating-point unit; studies the architecture of Floating-Point Unit. To solve the deficiency which FPU design depended on software. We propose a project of the FPU design which is suitable for FPGA.This approach enhances the portability and improvement of the system and higher calculating speed. The design unit is simulated, meeting the requirements of design and realizing logic synthesis in FPGA with the model Cyclone Ⅱ EP2C35F672C6. The result shows that the operating frequency is 47. 4MHZ to meet all requirements of the design.%针对以前浮点运算依靠软件实现的弊端,提出采用自顶向下的设计方法,模块化的设计思想来实现FPU整个设计,这种设计方法增强了系统的可移植性及可改进性;系统在CycloneⅡ EP2C35FC684C6的FPGA上综合实现,验证结果表明,在满足各项功能要求的前提下,其系统最高时钟频率可达到47.4MHZ,提高了浮点运算单元的处理速度.
Zinke, Stephan
2017-02-01
Memory sensitive applications for remote sensing data require memory-optimized data types in remote sensing products. Hierarchical Data Format version 5 (HDF5) offers user defined floating point numbers and integers and the n-bit filter to create data types optimized for memory consumption. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) applies a compaction scheme to the disseminated products of the Day and Night Band (DNB) data of Suomi National Polar-orbiting Partnership (S-NPP) satellite's instrument Visible Infrared Imager Radiometer Suite (VIIRS) through the EUMETSAT Advanced Retransmission Service, converting the original 32 bits floating point numbers to user defined floating point numbers in combination with the n-bit filter for the radiance dataset of the product. The radiance dataset requires a floating point representation due to the high dynamic range of the DNB. A compression factor of 1.96 is reached by using an automatically determined exponent size and an 8 bits trailing significand and thus reducing the bandwidth requirements for dissemination. It is shown how the parameters needed for user defined floating point numbers are derived or determined automatically based on the data present in a product.
An Efficient Architecture Design of Reconfigurable Float-point FFT Processor%高效可配置浮点FFT处理器设计
Institute of Scientific and Technical Information of China (English)
桑红石; 高伟
2012-01-01
Large resource cost is the design bottleneck of high-precision float-point FFT processor,a novel R2/22SDF reconfigurable architecture using shared-butterfly which employs single-port-based FIFO.Radix 2/22algorithm and pipeline architecture,which is suitable for float-point design,can reduce the multiplicative complexity and improve the multiplication efficiency.The FIFO memory using double-width single-port ram can avoid the larger area and power coat of dual-port ram.Two butterfly units can be merged by the proposed shared-butterfly architecture,which solves the low utilization factor problem of traditional single-path-delay-feedback architecture.The float-point design cost is efficiently reduced and the calculator utilization factor is improved,compared with the traditional pipeline method.%为了克服高精度浮点FFT处理器具有较大资源开销的设计瓶颈,采用基于单口存储器的FIFO构建共享蝶形结构的R2/22SDF流水可配置结构.采用适合浮点设计的基2/22算法实现流水结构,不仅有利于可配置电路的实现,还能够有效减少复数乘法次数,提高复数乘法器的计算效率.采用双倍数据位宽的单口存储器实现FIFO存储器,有效避免了双口存储器面积和功耗较大的问题.改进的蝶形共享结构实现两级蝶形的合并,解决了单路径延迟反馈流水线结构蝶形单元利用率低的问题.与传统流水线结构FFT处理器设计相比,有效降低了浮点设计中的资源开销,提高了计算单元的利用效率.
Institute of Scientific and Technical Information of China (English)
刘竹松; 陈平华; 陈璟
2011-01-01
In this paper, parameterized IP core design method is introduced into the design of floating-point unit, through extracting usable parameters, the floating-point unit can be designed into a parameterized, configurable, reusable IP core. Finally,simulation verified the feasibility and effectiveness of floating-point unit as parameterized IP core.%将参数化可配置IP核的设计方法引入到浮点运算器设计中,通过设计时提取的可用参数,将浮点运算器设计成为参数化、可配置、可重用的IP核.通过仿真验证了实现参数化IP核浮点运算器的可行性和有效性.
Directory of Open Access Journals (Sweden)
Yongsoon Lee
2009-01-01
Full Text Available This paper implements a field programmable gate array- (FPGA- based face detector using a neural network (NN and the bit-width reduced floating-point arithmetic unit (FPU. The analytical error model, using the maximum relative representation error (MRRE and the average relative representation error (ARRE, is developed to obtain the maximum and average output errors for the bit-width reduced FPUs. After the development of the analytical error model, the bit-width reduced FPUs and an NN are designed using MATLAB and VHDL. Finally, the analytical (MATLAB results, along with the experimental (VHDL results, are compared. The analytical results and the experimental results show conformity of shape. We demonstrate that incremented reductions in the number of bits used can produce significant cost reductions including area, speed, and power.
C语言中浮点数精度问题分析%Analysis on Precision of Floating-point Number for C Language
Institute of Scientific and Technical Information of China (English)
周冠方
2015-01-01
This article describes how data errors are caused in C language due to different data storage method with case study, an⁃alyses the reason for such errors and explains different storage methods of floating point data in C language. Finally, some sugges⁃tions are proposed in this article.%通过实例直观地描述了C语言中由于计算机存储数据方式的不同而造成的数据误差，并对误差产生的原因进行了分析，解读出C语言中浮点型数据的不同存储方式，最后给出几点建议。
Energy Technology Data Exchange (ETDEWEB)
Siy, P.F.; Carter, J.T.; D' Addario, L.R.; Loeber, D.A.
1991-08-01
The MITRE Corporation has performed in-flux radiation testing of the Texas Instruments TMS320C30 32-bit floating point digital signal processor in both total dose and dose rate radiation environments. This test effort has provided data relating to the applicability of the TMS320C30 in systems with total dose and/or dose rate survivability requirements. In order to accomplish these tests, the MITRE Corporation developed custom hardware and software for in-flux radiation testing. This paper summarizes the effort by providing an overview of the TMS320C30, MITRE's test methodology, test facilities, statistical analysis, and full coverage of the test results. (Author)
Kelly, G. L.; Berthold, G.; Abbott, L.
1982-01-01
A 5 MHZ single-board microprocessor system which incorporates an 8086 CPU and an 8087 Numeric Data Processor is used to implement the control laws for the NASA Drones for Aerodynamic and Structural Testing, Aeroelastic Research Wing II. The control laws program was executed in 7.02 msec, with initialization consuming 2.65 msec and the control law loop 4.38 msec. The software emulator execution times for these two tasks were 36.67 and 61.18, respectively, for a total of 97.68 msec. The space, weight and cost reductions achieved in the present, aircraft control application of this combination of a 16-bit microprocessor with an 80-bit floating point coprocessor may be obtainable in other real time control applications.
浮点指数函数的设计与实现%Design and Implementation of Floating-Point Exponential Function
Institute of Scientific and Technical Information of China (English)
李丽斯; 何虎
2012-01-01
An exponential function was designed for modern radar system. Numbers of floating-point were represented in IEEE-754 single precision format, which is 32- bit in length. Table-driven method was used to implement operation of floating-point exponential function, and CORDIC algotithm was introduced to simplify the design and improve the precision in a certain range. Based on the two algorithms, an improved architecture was proposed. The design was described in Verilog HDL and simulated with ModelSim6. 5b. Simulation results showed that the error range of the improved exponential function operation was reduced to 40% of the conventional method. Synthesized in 65 nm CMOS standard cell library, the circuit achieved an operating frequency of 483 MHz, satisfying requirements of the system.%设计了一种用于现代雷达系统的指数函数.设计中,浮点数格式均采用IEEE-754标准32位单精度表示[1].采用Table-driven算法实现浮点指数函数的运算.为了简化硬件的实现并提高算法实现的精度,引入了CORDIC算法.基于这两种算法结构,提出一种改进结构.采用Verilog语言描述,通过ModelSim6.5b进行仿真,结果表明,在一定的数据范围内,改进后指数函数运算结果的相对误差是传统方法的40％.在TMSC 65 nm工艺下综合,频率达到483 MHz,满足系统的工作频率要求.
High Accuracy Fast Floating-point Algorithm on Radar Terminal System%雷达终端高精度快速浮点算法研究
Institute of Scientific and Technical Information of China (English)
韩文俊; 张晓明; 杨东华
2012-01-01
In radar terminal system, floating-point operation when implemented in FPGA is time-consuming and with high resource u-tilization. After comparing current floating-point processing methods, CORDIC algorithm with high processing performance is selected. The theory of CORDIC algorithm is introduced in depth and the influence of bit wide and the iteration numbers to the accuracy is discussed by simulating. Finally, the implementation of arctan function in FPGA as an example is presented in detail. The results show that the speed is up to 210 MHz, the resource utilization is lower and the accuracy is higher which is also easy adjusted.%针对雷达终端处理过程中,浮点运算在现场可编程门阵列(FPGA)中实现较为耗时、资源占用较高的问题,首先在分析对比当前主要浮点处理方法的基础上,选择CORDIC算法进行浮点处理,并对算法原理进行了详细的介绍,通过仿真,分析了位宽及迭代次数对精度的影响.然后,以arctan函数为例详细介绍了其在FPGA中实现的方法,结果显示arctan流水运算速度可达200 MHz,资源占用率较低、实时性强、精度较高且易于调整.
2-Adic MRA based floating point representation Genetic Algorithm%2-Adic MRA的浮点数编码遗传算法
Institute of Scientific and Technical Information of China (English)
崔明义
2015-01-01
通过2-Adic多分辨率分析，构造正交小波基；证明所构造正交小波用于浮点数编码消噪的正确性；提出用正交小波在浮点数编码遗传算法中进行消噪变异操作，以消除浮点数编码在遗传环境中所产生的噪音对算法性能的影响；构建基于2-Adic多分辨率分析的遗传算法，并进行了实验。仿真实验表明，提出的算法可明显提高浮点数编码遗传算法的收敛速度和精度，具有较高的可靠性。%An orthonormal wavelet basis is constructed with 2-Adic multiresolution analysis. Validity of the constructed orthonormal wavelet is proven in denoising on Floating Point Representation Genetic Algorithm(FPRGA). Denoising muta-tion operation with the orthonormal wavelet is proposed in FPRGA. The aim is to remove noises from floating point repre-sentation in genetic environment. The genetic algorithm based on 2-Adic multiresolution analysis is structured. The experi-ment is done. The simulation experiment indicates that the algorithm can improve obviously convergence rate and preci-sion of FPRGA. It has greater reliability than base algorithm.
DEFF Research Database (Denmark)
Sørensen, Eigil V.; Aarup, Bendt
The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach a commercial breakthrough, wave energy converters need to achieve a lower price...... of energy produced, comparable to prices currently obtained from offshore wind power, and this can be done by the use of more suitable materials. The flotation device is a key part of converters, as it accounts for a considerable share of initial investment, up to 27% depending on the converter. CRC floats...
Separation of Potentials in the Two-Body Problem
Vasilyev, Andrey
2012-01-01
In contrast to the well-known solution of the two-body problem through the use of the concept of reduced mass, a solution is proposed involving separation of potentials. It is shown that each of the two point bodies moves in its own stationary potential well generated by the other body, and the magnitudes of these potentials are calculated. It is shown also that for each body separately the energy and the angular momentum laws are valid. The knowledge of the potentials in which the bodies are moving permits calculation of the trajectories of each body without resorting to the reduced mass. Key words: mechanics, two-body problem, gravitational potential, virial theorem.
Design of Floating Point Unit Verification System Based on Embedded Method%基于嵌入式方法的浮点单元验证系统设计
Institute of Scientific and Technical Information of China (English)
王云贵; 杨靓
2012-01-01
The verification of floating point unit is a big challenge. Based on Xilinx FX series FPGA which have powerpc405 hardcore embedded in it, use embedded system develop tool EDK, design an embedded system to verify floating point unit. The principium is through APU controller link user ip (the floating point unit under verification) to powerpc 405 core, write test program, through user defined instruction to access user ip, according to the instruction result we can know whether the floating point unit can function correctly in real circuit.%浮点单元的验证是最具挑战性的任务之一.基于Xilinx FX系列带powerpc 405硬核的FPGA,利用嵌入式系统开发套件EDK,设计了一个嵌入式系统对浮点单元进行验证.验证原理为把用户IP(被测浮点单元)通过APU控制器连接到powerpc 405处理器核,编写测试程序,通过自定义指令对用户IP进行访问,根据程序的运算结果判断被测IP的正确性.
Design of a 32-Bit CMOS Fix Floating Point Multiplier%32位定/浮点乘法器设计
Institute of Scientific and Technical Information of China (English)
于敦山; 沈绪榜
2001-01-01
针对Wallace树连接线复杂度高，版图实现比较困难的缺点，提出了一种新的加法器阵列结构.这种结构在规则性和连接复杂度方面优于ZM树和OS树.同时提出一种新的CLA加法器结构以提高乘法器的性能.乘法器采用1.5μm CMOS工艺实现，完成一次定点与浮点乘法操作的时间分别是56ns和76ns.%Wallace tree multipliers are very difficult to implement due to their complex routing requirement.A novel tree structure is presented，which requires simpler wiring than ZM trees and OS trees,and a novel CLA adder with 30% faster than the conventional one is proposed too to enhance the speed performance.The multiplier is fabricated with 1.5μm CMOS technology and can perform a 32-bit floating point multiplication(based on the proposed IEEE P754 standard format) and a 32-bit fixed point multiplication in 56ns and 76ns,respectively.
Institute of Scientific and Technical Information of China (English)
YIN PUMIN
2010-01-01
@@ One in six people in China have left their hometown in search of a better life and the number continues to grow,creating a challenge for host cities,according to a government report.The floating population,or people who live and work outside their permanent home,reached 211 million last year and the number could reach 350 million by 2050 if govemment policies remain unchanged,said the Report on the Development of China's Floating Population issued on June 26 by the National Population and Family Planning Commission (NPFPC).
浮点矩阵向量乘法的FPGA设计与优化%Design and Optimization of Floating-Point Matrix-Vector Multiply for FPGAs
Institute of Scientific and Technical Information of China (English)
薛永江; 宋庆增; 王瑞昆
2013-01-01
In this paper ,we design a matrix-vector multiplier which is based on IEEE-754 (32 bit ,64 bit) floating point data formats ,and the binary tree data flow .The implementation in FPGA platform is pipeline and highly efficient parallel .With Altera EP2C70 as the target device ,detailed study of the design of the hardware size ,clock speed ,capacity and peak GFLOPS .%提出了一种基于IEEE-754的32 bit、64 bit浮点数格式，二叉树数据流（binary tree data flow ）的矩阵向量乘法器。其在FPGA上流水线和高度并行化的高效执行。以Altera公司的EP2C70为实现设备，研究了设计的硬件规模，时钟速度，和峰值GFLOPS能力。
Institute of Scientific and Technical Information of China (English)
张雪姣; 伍萍辉
2011-01-01
Based on the IEEE floating point format and the FFT algorithm,this paper puts forward a 2FFT-based method based on FPGA.It completes the FFT design for the FPGA-based high-precision floating point unit.It describes the butterfly process and address generation unit processes by using VHDL.The simulation waveform can basically shows the output results correctly%基于IEEE浮点表示格式及FFT算法,提出一种基2FFT的FPGA方法,完成了基于FPGA高精度浮点运算器的FFT的设计。利用VHDL语言描述了蝶形运算过程及地址产生单元,其仿真波形基本能正确的表示输出结果
Institute of Scientific and Technical Information of China (English)
洪琪; 何敏; 范继聪; 袁粲
2014-01-01
As floating-point continuous multiply-add, fused multiply-add and multiply and three-operands addition operations are used more and more frequently in the field of scientific computing, a multi-purpose floating-point unit is designed which supports floating-point continuous multiply-add, fused multiply-add and multiply and three-operands addition is an urgent need. In this situation, a reconfigurable floating-point fused/continuous multiply-add structure is proposed. This reconfigurable floating-point fused/continuous multiply-adder can achieve a variety of floating-point data manipulation through configuration of the control bit. This reconfigurable floating-point fused/continuous multiply-adder uses eight-stage pipe-line. It can achieve single-cycle multiply-accumulate, which greatly improves the throughput of the data processing and supports three-operand addition and two-operand sum’s accumulate simultaneously. This design is simulated and verified in Modelsim SE6.6f’s environment and the function is correct. When this design is implemented on Xilinx Virtex-6 FPGA, the resource consumption is 2 631 LUTs and the frequency is up to 250 MHz, and the result proves that the reconfigurable floating-point fused/continuous multiply-adder has a large value in use.%浮点连续乘-加、混合乘-加和三操作数加等浮点算术运算在科学计算领域中应用越来越频繁，为设计一款支持浮点连续乘-加、混合乘-加和三操作数加的多功能浮点运算单元，提出一种可重构浮点混合/连续乘-加器，通过对控制位的配置可以实现多种浮点数据操作。该乘-加器采用8级流水线，可以实现单周期的浮点乘累加，大幅提高数据处理吞吐量，同时支持三操作数加和两操作数和的累加。在Modelsim SE6.6f中对该设计进行仿真验证，结果表明其能够在Xilinx Virtex-6 FPGA上实现，资源消耗2631个LUT，频率可达250 MHz，结果证明该浮点混合/连续乘-
Vandenberghe, Nicolas; Duchemin, Laurent
2016-01-01
When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends...
Nguyen, Phong Q.; Stehlé, Damien
2004-01-01
Everybody knows the Lenstra-Lenstra-Lovász lattice basis reduction algorithm (LLL), which has proved invaluable in public-key cryptanalysis and in many other fields. Given an integer $d$-dimensional lattice basis which vectors have norms smaller than $B$, LLL outputs a so-called LLL-reduced basis in time $O(d^6 \\log^3 B)$, using arithmetic operations on integers of bit-length $O(d \\logB)$. This worst-case complexity is problematic for lattices arising in cryptanalysis where $d$ or/and $\\logB$...
40 CFR 426.50 - Applicability; description of the float glass manufacturing subcategory.
2010-07-01
... float glass manufacturing subcategory. 426.50 Section 426.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Float Glass Manufacturing Subcategory § 426.50 Applicability; description of the float...
2015-01-01
ER D C/ CR RE L TR -1 5- 1 Engineering for Polar Operations, Logistics, and Research (EPOLAR) Bearing Capacity of Floating Ice Sheets...Operations, Logistics, and Research (EPOLAR) ERDC/CRREL TR-15-1 January 2015 Bearing Capacity of Floating Ice Sheets under Short-Term Loads Over-Sea-Ice... capacity for a single axle load of 66,000 lb; and the main beams have a minimum yield stress of 36 ksi.* The rounded ends of each girder reduce
Institute of Scientific and Technical Information of China (English)
何军; 黄永勤; 朱英
2014-01-01
高精度、高性能浮点运算部件是高性能微处理器设计的重要部分。通过对传统双精度浮点乘加运算算法的研究，结合四倍精度浮点数据格式特点，设计并实现一种高性能的四倍精度浮点乘加器(QPFMA)，该乘加器支持多种浮点运算，运算延迟为7拍，全流水结构。采用双路加法器改进算法结构，优化头零预测和规格化移位逻辑，减小运算延迟和硬件开销。通过参数化设计验证方法，实现高效的正确性验证。逻辑综合结果表明，基于65 nm 工艺，该 QPFMA 频率可达1.2 GHz，比现有的 QPFMA 设计运算延迟减少3拍，频率提高约11.63%。%High precision and high performance floating-point unit is an important research object of high performance microprocessor design. According to the characteristic of Quadruple Precision(QP) floating-point data format and research on double precision floating-point multiplier accumulator algorithms, a high performance Quadruple Precision Floating-point Multiplier Accumulator(QPFMA) is designed and realized, which supports multiple floating-point arithmetic with a 7 cycles pipeline. By adopting dual path adder and improving on algorithm architecture, optimizing leading-zero-anticipation and normalization shifter logic, the latency and hardware area is decreased. And by making use of parameterized design and verification methodology, the correction of the QPFMA is verified efficiently. Based on 65 nm technology, as the synthesis results show that the QPFMA can work at 1.2 GHz, with the latency decreased by 3 cycles and the frequency increased by about 11.63% compared with current QPFMA design.
Institute of Scientific and Technical Information of China (English)
翟振辉; 欧世峰; 刘继长; 钟全雄; 高颖
2014-01-01
IEEE 754标准规定了可以精确表示某一浮点型数据的单精度（常用）和双精度表示方法，这在许多对数据精度要求较高的场合得到广泛应用，而在数据通信过程中所有数据都是以十六进制打包和解析、二进制形式传输的，所以研究如何根据该标准把所要传输的浮点型数据编程转换成8位十六进制数据具有重要的实用意义。这里在分析和研究IEEE 754标准中浮点型数据单精度表示方式的基础上，结合Borland C++Builder 6.0可视化编程工具，阐述了如何把单精度浮点型数据转换成所需要的8位十六进制数，以及如何把8位十六进制数转换成单精度浮点类型数据，并实现显示。%The single precision and double precision expressive methods which can accurately express a float-point data are stipulated in IEEE754 standard. They are widely in the field,in which the accuracy requirement is high. On the base of studying and analyzing the expression of the 32 bits floating-point,how to translate the floating-point data to the needed hexadecimal da-ta,and how to translate the hexadecimal data to the floating-point data are elaborated in combination with the visual program-ming tools Borland C++ Builder 6.0,and the expression of the 32 bits floating-point data in the IEEE 754 standard. The data display was realized.
B. de Pablo Márquez; P. Castillón Bernal; I. Fuentes López
2014-01-01
La fractura concomitante de clavícula y escápula es una entidad poco frecuente que puede ser una de las causas de afectación del complejo suspensorio del hombro también denominado hombro flotante (floating shoulder). Se relaciona frecuentemente con traumatismos de alta energía. Presentamos un caso de esta patología en un paciente varón de 28 años que consultó por caída en bicicleta con contusión sobre hombro izquierdo. Se describen las diferentes opciones terapéuticas planteadas, las imágenes...
Research of Floating-point Summation and Dot-product Computing Architecture%浮点和与点积计算结构研究
Institute of Scientific and Technical Information of China (English)
姚涛; 高德远; 樊晓桠
2011-01-01
Floating -point (FP) summation and dot-product computing are widely used in many fields, such as scientific computing, digital signal processing and graphic processing. A general FP summation architecture which has one rounding error is proposed in this paper. A realignment method is employed in our architecture to eliminate the errors caused by the catastrophic cancellation or multi-sticky bits. Then, the architecture to computing dot-product is proposed based on the FP summation architecture. Furthermore, dot-product is combined with a SIMD unit. Lastly, A single precision FADD4 and a FDP4 are implemented which could improve the computing speed by 20.4% and 42. 1% respectively, compared with the traditional methods which employ discrete FP adders and multipliers to achieve FP Summation and dot product.%浮点数求和与点积计算在科学计算,信号处理,图像处理等领域中广泛应用.对浮点和与点积计算的硬件结构进行了研究.在只有一次舍入误差的前提下,提出一种通用的浮点数求和算法和结构,利用重对阶方法,解决了多个粘贴位和尾数过抵消所产生的精度损失问题.然后将这种算法移植到浮点点积计算中.为了增加结构的通用性,将提出的结构和常用的SIMD计算单元进行结合.根据提出的算法,设计实现了FADD4和FDP4的硬件结构,和使用离散的加法器和乘法器来实现求和与点积的方法相比,计算速度分别提高了20.4％和42.1％.
Two-body dissipation effects on synthesis of superheavy elements
Tohyama, M
2015-01-01
To investigate the two-body dissipation effects on the synthesis of superheavy elements, we calculate low-energy collisions of the $N=50$ isotones ($^{82}$Ge, $^{84}$Se, $^{86}$Kr and $^{88}$Sr) on $^{208}$Pb using the time-dependent density-matrix theory (TDDM). TDDM is an extension of the time-dependent Hartree-Fock (TDHF) theory and can determine the time evolution of one-body and two-body density matrices. Thus TDDM describes both one-body and two-body dissipation of collective energies. It is shown that the two-body dissipation may increase fusion cross sections and enhance the synthesis of superheavy elements.
Directory of Open Access Journals (Sweden)
B. de Pablo Márquez
2014-09-01
Full Text Available La fractura concomitante de clavícula y escápula es una entidad poco frecuente que puede ser una de las causas de afectación del complejo suspensorio del hombro también denominado hombro flotante (floating shoulder. Se relaciona frecuentemente con traumatismos de alta energía. Presentamos un caso de esta patología en un paciente varón de 28 años que consultó por caída en bicicleta con contusión sobre hombro izquierdo. Se describen las diferentes opciones terapéuticas planteadas, las imágenes radiológicas y una revisión de la literatura.
Institute of Scientific and Technical Information of China (English)
李晓靖
2015-01-01
提出一种基于时滞相关Logistic函数线性调频采样的浮点数据模糊加密算法优化技术，给出时滞相关Logistic函数及相关定义，研究了浮点数据的模糊编码算法，设计实时交互网络的浮点数据模糊加密方案，实现密钥稀疏集构造，采用基于稀疏矩阵的存储格式下的时滞相关Logistic函数浮点数据加密运算，构造密钥稀疏集，优化了算法性能。仿真结果表明，算法数据加密和解密性能较好，具有较高的数据吞吐量，能实现对大数据库的数据加密，提高了密文的不可预测性。%A sample Logistic function linear frequency based on the delay of floating-point data encryption algorithm for fuzzy optimization techniques is proposed, given the delay dependent Logistic function and definition of fuzzy coding algo⁃rithm, floating-point data, floating-point data design of real-time interactive network fuzzy encryption scheme is obtained. Realize the key sparse set structure, using encryption delay dependent Logistic function point data storage format based on the sparse matrix, key sparse sets are constructed, the performance of the algorithm is optimized. The simulation results show that, the algorithm of data encryption and decryption performance is good, the data throughput is higher, it can realize the data encryption of database, the cipher text is unpredictable.
高性能浮点除法和开方的设计与实现%Design and Implementation of High-performance Float-point Division and Square Root
Institute of Scientific and Technical Information of China (English)
洪琪; 赵志伟; 何敏
2013-01-01
在基于现场可编程门阵列(FPGA)的设计中，低延时、高吞吐量、小面积是3个主要考虑因素。针对以上因素，提出不同基数SRT浮点除法和开方算法，设计基于Virtex-II pro FPGA的可变位宽浮点除法和开方的3种实现方案，包括小面积的迭代实现、低延时的阵列实现和高吞吐量的流水实现。实验结果表明，对于浮点除法和开方算法的流水实现，在综合面积符合要求的基础上，实现频率最高分别可达到180 MHz和200 MHz以上，证明了该实现方案的有效性。%Low latency, high throughput and small area are three major design considerations of a design based on FPGA. In view of the above factors, this paper puts forward different cardinal SRT float-point division and square root algorithm. It designs three implementations of float-point division and square root operations with variable width based on Virtex-II pro FPGA. One is a low cost iterative implementation, another is a low latency array implementation, and the third is a high throughput pipelined implementation. Experimental results show that the highest frequencies for the float-point division and square root algorithm can reach above 180 MHz and 200 MHz respectively with meeting the needs of synthesized area. It fully verifies the effectiveness of the implementation plan.
Energy Technology Data Exchange (ETDEWEB)
Hopwood, J.
1978-02-01
A microprocessor-based, stored-program controller which incorporates a floating-point arithmetic unit to perform complex mathematical computations was developed to determine the thickness of conductors on printed wiring boards. Conductor thickness is calculated from measured resistance by means of curve-fitting equations in the stored program. Called a film thickness calculator, the instrument demonstrates a method which may serve as a basis for other designs involving microprocessor-based data acquisition systems requiring low-speed calculations. 19 figures.
Institute of Scientific and Technical Information of China (English)
杜鹤; 买培培; 苏涛; 张子敬
2011-01-01
With the coninuous development of radar signal processing technology, more requirements for parallel processing and precision have been put forward. Systolic structure is one of the key structures of parallel processing in radar signal processing. In this paper, a floating-point systolic structure based on QR_RLS algorithm is described. To improve computing speed and take advantage of multiplier resources, a custom floating-point format and the floating-point unit design in the format are introduced. Also,the square root algorithm and computing speed are both improved. This systolic structure is implemented on FPGA, and the results show that on the premise of improved computing accuracy, the systolic structure in the custom floating-point format reduces the occupancy of the corresponding resources. The result can be used as reference in real-time signal processing.%随着雷达信号处理技术的不断发展,对实时并行性和处理精度都提出了更高的要求,脉动阵结构是雷达信号处理中一种关键并行处理结构.文中介绍了一种基于QR_RLS算法的浮点脉动阵结构.为了提高运算速度,充分利用资源,引入了自定义浮点格式及该格式下的浮点运算单元的设计,并改进了平方根算法,提高了运算精度.在FPGA上实现了这种脉动阵结构,结果表明这种自定义浮点格式的脉动阵结构在提高了运算精度的同时,降低了相应的资源占用率,对实时信号处理的工程设计具有较高的参考价值.
The Sharma-Parthasarathy stochastic two-body problem
Energy Technology Data Exchange (ETDEWEB)
Cresson, J. [LMAP/Université de Pau, 64013 Pau (France); SYRTE/Observatoire de Paris, 75014 Paris (France); Pierret, F. [SYRTE/Observatoire de Paris, 75014 Paris (France); Puig, B. [IPRA/Université de Pau, 64013 Pau (France)
2015-03-15
We study the Sharma-Parthasarathy stochastic two-body problem introduced by Sharma and Parthasarathy in [“Dynamics of a stochastically perturbed two-body problem,” Proc. R. Soc. A 463, 979-1003 (2007)]. In particular, we focus on the preservation of some fundamental features of the classical two-body problem like the Hamiltonian structure and first integrals in the stochastic case. Numerical simulations are performed which illustrate the dynamical behaviour of the osculating elements as the semi-major axis, the eccentricity, and the pericenter. We also derive a stochastic version of Gauss’s equations in the planar case.
The Sharma-Parthasarathy stochastic two-body problem
Cresson, J.; Pierret, F.; Puig, B.
2015-03-01
We study the Sharma-Parthasarathy stochastic two-body problem introduced by Sharma and Parthasarathy in ["Dynamics of a stochastically perturbed two-body problem," Proc. R. Soc. A 463, 979-1003 (2007)]. In particular, we focus on the preservation of some fundamental features of the classical two-body problem like the Hamiltonian structure and first integrals in the stochastic case. Numerical simulations are performed which illustrate the dynamical behaviour of the osculating elements as the semi-major axis, the eccentricity, and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
Multinucleon Ejection Model for Two Body Current Neutrino Interactions
Energy Technology Data Exchange (ETDEWEB)
Sobczyk, Jan T.; /Fermilab
2012-06-01
A model is proposed to describe nucleons ejected from a nucleus as a result of two-body-current neutrino interactions. The model can be easily implemented in Monte Carlo neutrino event generators. Various possibilities to measure the two-body-current contribution are discussed. The model can help identify genuine charge current quasielastic events and allow for a better determination of the systematic error on neutrino energy reconstruction in neutrino oscillation experiments.
Study and Implementation of Floating-point Operations Based on Cortex-M3 Core%Cortex-M3内核浮点型运算的研究与实现
Institute of Scientific and Technical Information of China (English)
梅静静; 王申良
2011-01-01
通过分析Cortex-M3内核的结构与浮点型格式,充分利用Cortex-M3内核中的分支预测、单周期乘法、硬件除法等众多功能强大的特性,使用Thumb-2指令集实现了单精度浮点型的加、减、乘、除与比较运算,并给出了加减法运算的流程图和除法运算的源程序.%By analyzing the Cortex-M3 core structure and floating-point format, this paper uses the Thumb-2 instruction set to achieve addition, subtraction, multiplication, division and comparison operations of single-precision floating-point numbers, making full use of such powerful features of Cortex-M3 core as branch prediction, single-cycle multiplication and hardware division. The flow chart of addition and subtraction operations, as well as the source program of division operation, is provided.
Institute of Scientific and Technical Information of China (English)
何同祥; 韩宁青; 李洪亮; 常保春
2011-01-01
This article introduces PID parameter optimization method based on the floating-point coded genetic algorithm, using the performance index -time squared integral of the error as the objective function, making use of the global search ability of genetic algorithm to achieve an optimum solution of the optimization, to reduce the difficulty to design PID performance, and overall improve system performance. The simulation results show that coded by floating-point genetic algorithm parameter optimization enables system PI has a good dynamic quality and steady state characteristics.%本文介绍了基于浮点数编码遗传算法寻优的PID参数优化方法,采用误差绝对值时间平方积分性能指标作为参数选择的目标函数,利用遗传算法的全局搜索能力,实现对全局最优解的寻优,以降低PID参数整定的难度,达到总体提高系统性能的目的.仿真结果表明,通过浮点数编码遗传算法进行PI参数优化可使系统具有很好的动态品质和稳态特性.
Energy Technology Data Exchange (ETDEWEB)
Haller, G.M.; Freytag, D.R. [Stanford Univ., CA (United States). Stanford Linear Accelerator Center
1996-06-01
The design and implementation of an analog floating-point sampling integrated circuit for the BaBar detector at the SLAC B-Factory is described. The CARE (Custom Auto-Range Encoding) circuit is part of an 18-bit dynamic range sampling system with a 4-MHz waveform digitization rate for the CsI calorimeter. The architecture and methodology of the system are described. The CARE integrated circuit receives dual-range (gain of 1 and 32) 13-bit signals from the 18-bit range preamplifiers mounted directly on the CsI crystals and converts the input at a rate of 4 MHz to an auto-range floating-point format with a 10-bit analog mantissa and 2 digital range bits (for 4 ranges). Additional functions integrated on the chip are averaging and selection circuitry for signals originating from two independent diodes per crystal and range-selection overwrite circuitry. The circuit will be mounted within the detector structure and thus low power dissipation is essential. The circuit has been fabricated in a 1.2 {micro}m BiCMOS process with polysilicon-to-polysilicon capacitors and polysilicon resistors. Measurement results are presented. One complete CARE channel dissipates 25 mW.
Institute of Scientific and Technical Information of China (English)
张帆; 刘志红
2014-01-01
非线性双曲Schrödinger函数在计算机编码和通用处理器设计中具有广阔用途，双曲微分方程求解作为单浮点Cache加速器设计的核心算法。传统方法采用稀疏矩阵向量乘方法进行单浮点Cache加速器设计，当微分矩阵的阶数较大时，不能直接进行随机搜索，对具有单浮点数据格式的算法加速性能不好。提出一种基于非线性双曲Schrödinger函数的单浮点Cache加速器优化设计方法，采用非线性双曲Schrödinger函数进行矩阵重排序方法，并进行非线性编码，引入稀疏矩阵向量乘单浮点Cache数据结构。采用三级流水线结构设计单浮点Cache加速器，基于Xilinx Virtex-5平台进行数据并行处理性能测试，得出该算法单浮点Cache并行运算加速比比传统方法大1.37~2.60倍，且有优越的数据吞吐性能，稳定性好，在数据库执行算法的并行处理和外部存储器的带宽利用率提高等方面有很好的应用价值。%Nonlinear hyperbolic Schrödinger function has a wide use in the computer code and general processor design, hy-perbolic differential equations is the a core algorithm for single floating-point Cache accelerator design. Traditional method using sparse matrix vector multiplication method for single floating-point Cache accelerator design, when the differential matrix is large, it cannot directly carry out random search, acceleration performance is not good. A kind of single floating-point Cache accelerator optimization method sis designed is proposed base on nonlinear hyperbolic Schrödinger function, the matrix reordering method is used, and nonlinear coding is taken, the sparse matrix vector multiplication single floating-point Cache data structure is introduced. Three stage pipeline structures are used to design a single floating-point Cache accelerator, data parallel processing performance test is taken based on Xilinx Virtex-5, and it shows that the parallel com
Heng, Kenneth
2016-12-01
"Floating shoulder" is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.
Sensitivity analysis of random two-body interactions
Johnson, Calvin W
2010-01-01
The input to the configuration-interaction shell model includes many dozens or hundreds of independent two-body matrix elements. Previous studies have shown that when fitting to experimental low-lying spectra, the greatest sensitivity is to only a few linear combinations of matrix elements. Here we consider interactions drawn from the two-body random ensemble, or TBRE, and find that the low-lying spectra are also most sensitive to only a few linear combinations of two-body matrix elements, in a fashion nearly indistinguishable from an interaction empirically fit to data. We find in particular the spectra for both the random and empirical interactions are sensitive to similar matrix elements, which we analyze using monopole and contact interactions.
Wave Function Structure in Two-Body Random Matrix Ensembles
Kaplan, L; Kaplan, Lev; Papenbrock, Thomas
2000-01-01
We study the structure of eigenstates in two-body interaction random matrix ensembles and find significant deviations from random matrix theory expectations. The deviations are most prominent in the tails of the spectral density and indicate localization of the eigenstates in Fock space. Using ideas related to scar theory we derive an analytical formula that relates fluctuations in wave function intensities to fluctuations of the two-body interaction matrix elements. Numerical results for many-body fermion systems agree well with the theoretical predictions.
Vandenberghe, Nicolas
2016-01-01
When impacted by a rigid object, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. In the first place, a longitudinal wave front -- associated with in-plane deformation of the membrane and traveling at constant speed -- separates an outward stress free domain with a stretched but flat domain. Then, in the stretched domain a dispersive transverse wave travels at a wave speed that depends on the local stretching rate. We study the dynamics of this fluid-body system and we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. We emphasize the role of the stretching in the membrane in the wave dynamics but also in the development of a buckling instability that give rise to radial wrinkles.
Institute of Scientific and Technical Information of China (English)
曲英杰; 夏宏; 王沁
2001-01-01
该文给出了一种微处理器浮点运算功能的测试方法，该方法的测试工作量少、测试时间短，而同时又具有较高的测试覆盖率。工程实践表明，该方法确实是一种可行的、有效的功能测试方法。%A functional testing method for floating-point arithmetic is proposed in thispaper,it spends little testingwork and time,but it has high test coverage rate relatively. Practice of engineering proves that this method is practicable and effective.
Design and implementation of fast single-precision floating-point arithmetic unit%快速单精度浮点运算器的设计与实现
Institute of Scientific and Technical Information of China (English)
田红丽; 闫会强; 赵红东
2011-01-01
浮点运算单元FPU( Floating-point Unit)在当前CPU的运算中地位越来越重要,论文中实现了一种基于FPGA的快速单精度浮点运算器.该运算器采用了流水线和并行计算技术,使得浮点教运算的速度有了显著的提高.在QUARTUSII 7.1系统上对运算器已仿真成功,结果表明它可以运行在40.5MHz时钟工作频率下,能快速准确地完成各种加、减、乘和除算术运算.
Two-body quantum mechanical problem on spheres
2005-01-01
The quantum mechanical two-body problem with a central interaction on the sphere ${\\bf S}^{n}$ is considered. Using recent results in representation theory an ordinary differential equation for some energy levels is found. For several interactive potentials these energy levels are calculated in explicit form.
Stochastic perturbation of the two-body problem
Jacky, Cresson; Bénédicte, Puig
2014-01-01
We study the impact of a stochastic perturbation on the classical two-body problem in particular concerning the preservation of first integrals and the Hamiltonian structure. Numerical simulations are performed which illustrate the dynamical behavior of the osculating elements as the semi-major axis, the eccentricity and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
Stochastic perturbation of the two-body problem
Cresson, J.; Pierret, F.; Puig, B.
2013-11-01
We study the impact of a stochastic perturbation on the classical two-body problem in particular concerning the preservation of first integrals and the Hamiltonian structure. Numerical simulations are performed which illustrate the dynamical behavior of the osculating elements as the semi-major axis, the eccentricity and the pericenter. We also derive a stochastic version of Gauss's equations in the planar case.
Two-body threshold spectral analysis, the critical case
DEFF Research Database (Denmark)
Skibsted, Erik; Wang, Xue Ping
We study in dimension $d\\geq2$ low-energy spectral and scattering asymptotics for two-body $d$-dimensional Schrödinger operators with a radially symmetric potential falling off like $-\\gamma r^{-2},\\;\\gamma>0$. We consider angular momentum sectors, labelled by $l=0,1,\\dots$, for which $\\gamma...
Exact phase space functional for two-body systems
Gracia-Bondía, José M
2010-01-01
The determination of the two-body density functional from its one-body density is achieved for Moshinsky's harmonium model, using a phase-space formulation, thereby resolving its phase dilemma. The corresponding sign rules can equivalently be obtained by minimizing the ground-state energy.
Floating wetlands for urban stormwater treatment
Wang, Chih-Yu
2013-01-01
A floating treatment wetland (FTW) is an ecological approach which seeks to reduce point and nonpoint source pollution by installing substrate rooted plants grown on floating mats in open waters. While relatively novel, FTW use is increasing. A review of literature identified several research gaps, including: (1) assessments of the treatment performance of FTWs; (2) evaluations of FTWs in the U.S., particularly within wet ponds that receive urban runoff; and (3) plant temporal nutrient distri...
Atlas2bgeneral: Two-body resonance calculator
Gallardo, Tabaré
2016-07-01
For a massless test particle and given a planetary system, Atlas2bgeneral calculates all resonances in a given range of semimajor axes with all the planets taken one by one. Planets are assumed in fixed circular and coplanar orbits and the test particle with arbitrary orbit. A sample input data file to calculate the two-body resonances is available for use with the Fortran77 source code.
Classical and Quantum Two-Body Problem in General Relativity
Maheshwari, Amar; Todorov, Ivan
2016-01-01
The two-body problem in general relativity is reduced to the problem of an effective particle (with an energy-dependent relativistic reduced mass) in an external field. The effective potential is evaluated from the Born diagram of the linearized quantum theory of gravity. It reduces to a Schwarzschild-like potential with two different `Schwarzschild radii'. The results derived in a weak field approximation are expected to be relevant for relativistic velocities.
基于补偿的浮点八边形抽象域%Compensation-based floating-point octagon abstract domain
Institute of Scientific and Technical Information of China (English)
王瑞; 吴世堂; 李宁; 李战怀
2015-01-01
The main difficulties of floating‐point programs analysis based on abstract interpretation ex‐ist in costly computation brought by the real number arithmetic w hen constructing the complex ab‐stract domain .In this paper ,a compensation‐based floating‐point number representation and relative arithmetic were proposed based on IEEE754 standard for octagon abstract domain .The method could reduce the complexity of floating‐point arithmetic ,and extend the traditional octagon abstract domain to sound floating‐point octagon abstract domain ,achieving a trade‐off between efficiency and preci‐sion .Experimental results show that using the compensation‐based floating‐point octagon abstract do‐main rather than real number can significantly improve the efficiency ,and ensure the reliability of analy sis .%为了解决抽象解释理论对浮点程序分析中的主要困难存在于构造复杂抽象域时采用实数而受限于高代价的计算量问题，针对八边形抽象域上实数运算提出了基于IEEE754的带补偿量的机器浮点表示及其运算算法，减少了浮点运算的复杂性；同时，将传统八边形抽象域扩展为可靠的浮点八边形抽象域，能够在分析的效率和精度之间取得合理的权衡。实验结果表明：用带补偿的浮点替代实数能够极大地提高八边形抽象域的效率，并且保证了分析的可靠性。
Separable approximation method for two-body relativistic scattering
Energy Technology Data Exchange (ETDEWEB)
Tandy, P.C.; Thaler, R.M.
1988-03-01
A method for defining a separable approximation to a given interaction within a two-body relativistic equation, such as the Bethe-Salpeter equation, is presented. The rank-N separable representation given here permits exact reproduction of the T matrix on the mass shell and half off the mass shell at N selected bound state and/or continuum values of the invariant mass. The method employed is a four-space generalization of the separable representation developed for Schroedinger interactions by Ernst, Shakin, and Thaler, supplemented by procedures for dealing with the relativistic spin structure in the case of Dirac particles.
Separable approximation method for two-body relativistic scattering
Tandy, P. C.; Thaler, R. M.
1988-03-01
A method for defining a separable approximation to a given interaction within a two-body relativistic equation, such as the Bethe-Salpeter equation, is presented. The rank-N separable representation given here permits exact reproduction of the T matrix on the mass shell and half off the mass shell at N selected bound state and/or continuum values of the invariant mass. The method employed is a four-space generalization of the separable representation developed for Schrödinger interactions by Ernst, Shakin, and Thaler, supplemented by procedures for dealing with the relativistic spin structure in the case of Dirac particles.
Two-body bound states in quantum electrodynamics. [Rate
Energy Technology Data Exchange (ETDEWEB)
Lepage, G.P.
1978-07-01
Novel formulations of the two-body bound state problem in quantum field theory are examined. While equal in rigor, these have several calculational advantages over the traditional Bethe-Salpeter formalism. In particular there exist exact solutions of the bound state equations for a Coulomb-like interaction in quantum electrodynamics. The corrections to such zeroth-order solutions can be systematically computed in a simple perturbation theory. These methods are illustrated by computing corrections to the orthopositronium decay rate and to the ground state splittings in positronium and muonium.
Covariant Hamiltonian for the electromagnetic two-body problem
De Luca, Jayme
2005-09-01
We give a Hamiltonian formalism for the delay equations of motion of the electromagnetic two-body problem with arbitrary masses and with either repulsive or attractive interaction. This dynamical system based on action-at-a-distance electrodynamics appeared 100 years ago and it was popularized in the 1940s by the Wheeler and Feynman program to quantize it as a means to overcome the divergencies of perturbative QED. Our finite-dimensional implicit Hamiltonian is closed and involves no series expansions. As an application, the Hamiltonian formalism is used to construct a semiclassical canonical quantization based on the numerical trajectories of the attractive problem.
Two-body bound states & the Bethe-Salpeter equation
Energy Technology Data Exchange (ETDEWEB)
Pichowsky, M. [Argonne National Lab., IL (United States); Kennedy, M. [Univ. of New Hampshire, Durham, NH (United States). Physics Dept.; Strickland, M. [Duke Univ., Durham, NC (United States)
1995-01-18
The Bethe-Salpeter formalism is used to study two-body bound states within a scalar theory: two scalar fields interacting via the exchange of a third massless scalar field. The Schwinger-Dyson equation is derived using functional and diagrammatic techniques, and the Bethe-Salpeter equation is obtained in an analogous way, showing it to be a two-particle generalization of the Schwinger-Dyson equation. The authors also present a numerical method for solving the Bethe-Salpeter equation without three-dimensional reduction. The ground and first excited state masses and wavefunctions are computed within the ladder approximation and space-like form factors are calculated.
Institute of Scientific and Technical Information of China (English)
刘容; 赵洪深; 李晓今
2013-01-01
在修正型Booth算法和Wallace树结构以及选择进位加法器的基础上，提出了一种新型32位单精度浮点乘法器结构。该新型结构通过截断选择进位加法器进位链，缩短了关键路径延时。传统选择进位加法器每一级加法器的进位选择来自上级的进位输出。提出的结构可以提前计算出尾数第16位的结果，它与Wallace树输出的相关位比较就可得出来自前一位的进位情况进而快速得到进位选择。在Altera的EP2C70F896C6器件上，基于该结构实现了一个支持IEEE754浮点标准的4级流水线浮点乘法器，时序仿真表明，该方法将传统浮点乘法器结构关键路径延时由6.4 ns减小到5.9 ns。%On the basis of the modified Booth encoding,Wallace tree structure and carry-select adder,a new structure of 32-bit float point multiplier is proposed,which can shorten its critical path delay by cutting the carry chain. The carry selection of each level of the carry-select adder comes from the upper carry output. The new structure can produce the 16th bit of the man-tissa. By comparing it with the relative output bit of the Wallace tree,the carry which comes from the former bit can be got to achieve the carry selection. By using the new structure,a 4-stage pipeline float point multiplier supporting IEEE754 standard is implemented on Altera’s FPGA device EP2C70F896C6. The time-sequence simulation shows that the critical path delay of the multiplier is 5.9 ns,less than that of the traditional multiplier,which is 6.4 ns.
Two-body bound state problem and nonsingular scattering equations
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Sandhas, W.
1986-11-01
We present a new momentum space approach to the two-body problem in partial waves. In contrast to the usual momentum space approaches, we treat the bound state case with the help of an inhomogeneous integral equation which possesses solutions for all (negative) energies. The bound state energies and corresponding wave functions are identified by an additional condition. This procedure straightforwardly leads to a nonsingular formulation of the scattering problem in terms of essentially the same equation and thus unifies the descriptions of both energy regimes. We show that the properties of our momentum-space approach can be understood in terms of the so-called regular solution of the Schroedinger equation in position space. The unified description of the bound state and scattering energy regimes in terms of one single, real, and manifestly nonsingular equation allows us to construct an exact representation of the two-body off-shell T matrix in which all the bound state pole and scattering cut information is contained in one single separable term, the remainder being real, nonsingular, and vanishing half on-shell. Such a representation may be of considerable advantage as input in three-body Faddeev-type integral equations. We demonstrate the applicability of our method by calculating bound state and scattering data for the two-nucleon system with the s-wave Malfliet--Tjon III potential.
Vandenberghe, Nicolas; Duchemin, Laurent
2016-05-01
When impacted by a rigid body, a thin elastic membrane with negligible bending rigidity floating on a liquid pool deforms. Two axisymmetric waves radiating from the impact point propagate. First, a longitudinal wave front, associated with in-plane deformation of the membrane and traveling at constant speed, separates an outward stress-free domain from a stretched domain. Then, in the stretched domain a dispersive transverse wave travels at a speed that depends on the local stretching rate. The dynamics is found to be self-similar in time. Using this property, we show that the wave dynamics is similar to the capillary waves that propagate at a liquid-gas interface but with a surface tension coefficient that depends on impact speed. During wave propagation, we observe the development of a buckling instability that gives rise to radial wrinkles. We address the dynamics of this fluid-body system, including the rapid deceleration of an impactor of finite mass, an issue that may have applications in the domain of absorption of impact energy.
Institute of Scientific and Technical Information of China (English)
韩赛; 杜普选
2012-01-01
This paper focused on the research and design of Floating-point DSP Experimental Teaching System based on ADSP-21369. It was implemented the control of SDRAM, FLASH, ADC, DDS and other external memory by ADSP-21369 and other analog devices. LCD, UART and keyboard could be controlled by using ADSP-21369's inherent resources and the digital peripheral interface (DPI). The digital application interface (DAI) could be used to control the audio, S/PDIF and LED.%本文研究并设计出一套基于ADSP-21369的浮点DSP教学实验系统.采用ADSP-21369处理器,辅以其它模拟器件,实现对SDRAM,FLASH,ADC和DDS等外部存储器的控制.利用ADSP-21369的固有资源,通过数字外设接口(DPI)完成对LCD,UART及键盘控制,通过数字应用接口(DAI)完成对音频,S/PDIF和LED灯等的控制.
Fukushima, Toshio
2012-11-01
We confirm that the first-, second-, and third-order derivatives of fully-normalized Legendre polynomial (LP) and associated Legendre function (ALF) of arbitrary degree and order can be correctly evaluated by means of non-singular fixed-degree formulas (Bosch in Phys Chem Earth 25:655-659, 2000) in the ordinary IEEE754 arithmetic when the values of fully-normalized LP and ALF are obtained without underflow problems, for e.g., using the extended range arithmetic we recently developed (Fukushima in J Geod 86:271-285, 2012). Also, we notice the same correctness for the popular but singular fixed-order formulas unless (1) the order of differentiation is greater than the order of harmonics and (2) the point of evaluation is close to the poles. The new formulation using the fixed-order formulas runs at a negligible extra computational time, i.e., 3-5 % increase in computational time per single ALF when compared with the standard algorithm without the exponent extension. This enables a practical computation of low-order derivatives of spherical harmonics of arbitrary degree and order.
Nonleptonic two-body Bc-meson decays
Naimuddin, Sk.; Kar, Susmita; Priyadarsini, M.; Barik, N.; Dash, P. C.
2012-11-01
We study the exclusive nonleptonic two-body Bc decays within factorization approximation, in the framework of the relativistic independent quark model based on a confining potential in the scalar-vector harmonic form. The relevant weak form factors and branching ratios for different decay modes (Bc→PP,PV,VP) are predicted in reasonable agreement with other quark model predictions. We find that the dominant contribution to the Bc-meson lifetime comes from the Cabibbo-Kobayashi-Masakawa favored c¯→s¯, d¯ decay modes, and the most promising modes are found to be Bc-→B¯s0π-, Bc-→B¯s0ρ- and Bc-→B¯s⋆0π- with predicted branching ratios of 12.01, 9.96, and 8.61%, respectively, which might be easily detected at the hadron collider in the near future.
Two-body Dirac equation approach to the deuteron
Energy Technology Data Exchange (ETDEWEB)
Galeao, A.P.; Castilho A, J.A.; Ferreira, P. Leal
1996-06-01
The two-body Dirac (Breit) equation with potentials associated to one-boson-exchanges with cutoff masses is solved for the deuteron and its observables calculated. The 16-component wave-function for the J{sup {pi}} = 1{sup +} state contains four independent radial functions which satisfy a system of four coupled differential equations of firs order. This system is numerically integrated, from infinity towards the origin, by fixing the value of the deuteron binding energy and imposing appropriate boundary conditions at infinity. For the exchange potential of the pion, a mixture of direct plus derivative couplings to the nucleon is considered. We varied the pion-nucleon coupling constant, and the best results of our calculations agree with the lower values recently determined for this constant. The present treatment differs from the more conventional ones in that non-relativistic reductions up to the order c{sup -2} are not used. (author). 20 refs., 1 fig., 2 tabs.
Visualized kinematics code for two-body nuclear reactions
Lee, E. J.; Chae, K. Y.
2016-05-01
The one or few nucleon transfer reaction has been a great tool for investigating the single-particle properties of a nucleus. Both stable and exotic beams are utilized to study transfer reactions in normal and inverse kinematics, respectively. Because many energy levels of the heavy recoil from the two-body nuclear reaction can be populated by using a single beam energy, identifying each populated state, which is not often trivial owing to high level-density of the nucleus, is essential. For identification of the energy levels, a visualized kinematics code called VISKIN has been developed by utilizing the Java programming language. The development procedure, usage, and application of the VISKIN is reported.
A search for two body muon decay signals
Bayes, R; Davydov, Yu I; Depommier, P; Faszer, W; Fujiwara, M C; Gagliardi, C A; Gaponenko, A; Gill, D R; Grossheim, A; Gumplinger, P; Hasinoff, M D; Henderson, R S; Hillairet, A; Hu, J; Koetke, D D; MacDonald, R P; Marshall, G M; Mathie, E L; Mischke, R E; Olchanski, K; Olin, A; Openshaw, R; Poutissou, J -M; Poutissou, R; Selivanov, V; Sheffer, G; Shin, B; Stanislaus, T D S; Tacik, R; Tribble, R E
2014-01-01
Lepton family number violation is tested by searching for $\\mu^+\\to e^+X^0$ decays among the 5.8$\\times 10^8$ positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive $X^0$ bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic $\\mu^+\\to e^+X^0$ decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order $10^{-5}$\\ are obtained for boson masses of 10 - 80 MeV/c$^2$ and different asymmetries. For lighter bosons the asymmetry dependence is much stronger and the branching ratio limit varies up to $5.8 \\times 10^{-5}$. This is the first study that explicitly evaluates the limits for anisotropic two body muon decays.
Orbit Determination with the two-body Integrals. II
Gronchi, Giovanni F; Dimare, Linda
2011-01-01
The first integrals of the Kepler problem are used to compute preliminary orbits starting from two short observed arcs of a celestial body, which may be obtained either by optical or radar observations. We write polynomial equations for this problem, that we can solve using the powerful tools of computational Algebra. An algorithm to decide if the linkage of two short arcs is successful, i.e. if they belong to the same observed body, is proposed and tested numerically. In this paper we continue the research started in [Gronchi, Dimare, Milani, 'Orbit determination with the two-body intergrals', CMDA (2010) 107/3, 299-318], where the angular momentum and the energy integrals were used. A suitable component of the Laplace-Lenz vector in place of the energy turns out to be convenient, in fact the degree of the resulting system is reduced to less than half.
Loschmidt echoes in two-body random matrix ensembles
Pižorn, Iztok; Prosen, Tomaž; Seligman, Thomas H.
2007-07-01
Fidelity decay is studied for quantum many-body systems with a dominant independent particle Hamiltonian resulting, e.g., from a mean field theory with a weak two-body interaction. The diagonal terms of the interaction are included in the unperturbed Hamiltonian, while the off-diagonal terms constitute the perturbation that distorts the echo. We give the linear response solution for this problem in a random matrix framework. While the ensemble average shows no surprising behavior, we find that the typical ensemble member as represented by the median displays a very slow fidelity decay known as “freeze.” Numerical calculations confirm this result and show that the ground state even on average displays the freeze. This may contribute to explanation of the “unreasonable” success of mean field theories.
Micromagnetic simulation of two-body magnetic nanoparticles
Li, Fei; Lu, Jincheng; Yang, Yu; Lu, Xiaofeng; Tang, Rujun; Sun, Z. Z.
2017-05-01
Field-induced magnetization dynamics was investigated in a system of two magnetic nanoparticles with uniaxial anisotropies and magnetostatic interaction. By using the micromagnetic simulation, ultralow switching field strength was found when the separation distance between the two particles reaches a critical small value on nanometer scale in the perpendicular configuration where the anisotropic axes of the two particles are perpendicular to the separation line. The switching field increases sharply when the separation is away from the critical distance. The same results were observed when varying the radius of particles. The micromagnetic results are consistent with the previous theoretical prediction where dipolar interaction between two single-domain magnetic particles was considered. Our present simulations offered further proofs and possibilities for the low-power applications of information storage as the two-body magnetic nanoparticles could be implemented as a composite information bit.
Simulated floating zone method
Ozawa, Ryo; Kato, Yasuyuki; Motome, Yukitoshi
2016-01-01
This paper provides the simulated floating zone (SFZ) method that is an efficient simulation technique to obtain thermal equilibrium states, especially useful when domain formation prevents the system from reaching a spatially-uniform stable state. In the SFZ method, the system is heated up locally, and the heated region is steadily shifted, similar to the floating zone method for growing a single crystal with less lattice defect and impurity in experiments. We demonstrate that the SFZ method...
Strong Two--Body Decays of Light Mesons
Ricken, R; Merten, D; Metsch, B C; Ricken, Ralf; Koll, Matthias; Merten, Dirk; Metsch, Bernard C.
2003-01-01
In this paper, we present results on strong two-body decay widths of light $q\\bar q$ mesons calculated in a covariant quark model. The model is based on the Bethe-Salpeter equation in its instantaneous approximation and has already been used for computing the complete meson mass spectrum and many electroweak decay observables. Our approach relies on the use of a phenomenological confinement potential with an appropriate spinorial Dirac structure and 't Hooft's instanton--induced interaction as a residual force for pseudoscalar and scalar mesons. The transition matrix element for the decay of one initial meson into two final mesons is evaluated in lowest order by considering conventional decays via quark loops as well as Zweig rule violating instanton--induced decays generated by the six--quark vertex of 't Hooft's interaction; the latter mechanism only contributes if all mesons in the decay have zero total angular momentum. We show that the interference of both decay mechanisms plays an important role in the ...
Material loss in two-body collisions during planet formation
Werner, J.; Schäfer, C.; Maindl, T. I.; Burger, C.; Speith, R.
2016-02-01
During the formation process of a terrestrial planet, a planetary embryo does not only accrete smaller dust particles but also suffers collisions with larger planetesimals. When simulating these collisions, most N-body codes treat them as perfect merging events, i.e. the resulting body's mass is the sum of the previous ones. In our work, we aim to determine whether this assumption is a justified simplification, specifically focusing on bodies containing volatile elements, such as water. To analyze this, we have developed a new Smooth Particle Hydrodynamics (SPH) code that includes elasto-plastic dynamics, a damage model for brittle materials and self gravity. It makes use of the Compute Unified Device Architecture (CUDA) and runs on modern GPU architectures which allows for higher resolution in less calculation time. This enables us to take a precise look at two-body collisions and determine the amount of both transferred and ejected mass according to specific parameters such as mass ratio of impactor and target, porosity, impact velocity, impact angle and water distribution.
Two-body relaxation in modified Newtonian dynamics
Ciotti, L
2004-01-01
A naive extension to MOND of the standard computation of the two-body relaxation time Tb implies that Tb is comparable to the crossing time regardless of the number N of stars in the system. This computation is questionable in view of the non-linearity of MOND's field equation. A non-standard approach to the calculation of Tb is developed that can be extended to MOND whenever discreteness noise generates force fluctuations that are small compared to the mean-field force. It is shown that this approach yields standard Newtonian results for systems in which the mean density profile is either plane-parallel or spherical. In the plane-parallel case we find that in the deep-MOND regime Tbb scales with N as in the Newtonian case, but is shorter by the square of the factor by which MOND enhances the gravitational force over its Newtonian value for the same system. Application of these results to dwarf galaxies and groups and clusters of galaxies reveals that in MOND luminosity segregation should be far advanced in g...
一种快速SIMD浮点乘加器的设计与实现%Design and Implementation of a Fast SIMD Floating-Point Fused Multiply-Add Unit
Institute of Scientific and Technical Information of China (English)
吴铁彬; 刘衡竹; 杨惠; 张剑锋; 侯申
2012-01-01
本文设计和实现了5级全流水SIMD浮点乘加器,支持双精度和双单精度浮点乘法、乘累加(减)操作,用Modelsim和NC Verilog测试和验证了RTL代码实现,基于65nm工艺采用Synopsys公司的Design Complier工具综合硬件实现,运行频率可达714.286MHz.结果表明,相比文献[3]中经典的低延迟乘加结构,在相同综合条件下性能提升了17.89％,面积增加了6.61％,功耗降低了25.08％.%A new 5-stage pipelined architecture of floating-point fused multiply-add (FMAC) unit is proposed and implemented. In this architecture, double precision or double-single precision floatingpoint multiply,multiply-add and multiply-subtract operations are supported. The unit is implemented to RTL Code, and simulated and verified in Modelsim and NC Verilog. Further more, it is synthesized in the 65nm CMOS technology by Design Complier of Synopsys, and the frequency reaches 714. 286MHz. In addition, compared with the conventional low-delay FMAC of paper [3] in the same environment, a-part from 6. 61 percent of area which could be acceptable is increased, 17. 89 percent of delay and 25. 08 percent of power is reduced.
Floating point processor for photomultiplier tube signals
Energy Technology Data Exchange (ETDEWEB)
Baron, P.; Joudon, A.; Lugiez, F.; Rouger, M. [C.E.A. Saclay, Gif sur Yvette (France)
1995-08-01
A chip was provided to read out the channels of the Shower Maximum Detector (SMD) in the electromagnetic calorimeter (EMC) of the S.D.C. experiment (solenoidal Detector Collaboration) at the Superconducting Super Collider project and shape of the electromagnetic shower with better precision than can be done by the EMC alone. A fast digital readout system has been designed for synchronous processing of the current signals delivered by a 64-channel multichannel photomultiplier tube (MCPMT) associated with fast scintillators. This mixed analog digital full custom chip uses a 1.2{micro}m A.M.S. CMOS process.
Floating-Point $L^2$-Approximations
Brisebarre, Nicolas; Hanrot, Guillaume
2007-01-01
International audience; Computing good polynomial approximations to usual functions is an important topic for the computer evaluation of those functions. These approximations can be good under several criteria, the most desirable being probably that the relative error is as small as possible in the $L^{\\infty}$ sense, i.e. everywhere on the interval under study. In the present paper, we investigate a simpler criterion, the $L^2$ case. Though finding a best polynomial $L^2$-approximation with ...
Arithmetic Operations Beyond Floating Point Number Precision
Wang, Chih-Yueh; Yin, Chen-Yang; Chen, Hong-Yu; Chen, Yung-Ko
2010-01-01
In basic computational physics classes, students often raise the question of how to compute a number that exceeds the numerical limit of the machine. While technique of avoiding overflow/underflow has practical application in the electrical and electronics engineering industries, it is not commonly utilized in scientific computing, because scientific notation is adequate in most cases. We present an undergraduate project that deals with such calculations beyond a machine's numerical limit, kn...
Floating Point Multiply-Add-Subtract Implementation
2014-11-07
and the mantissa inputs, Aman and Bman, and scales these inputs relative to one another. An adder /subtractor 30 receives the scaled mantissa...calculated from the input exponents, Aexp and Bexp, in a multiplication exponent adder 44. Exponent calculation logic 46 receives the preliminary...Aexp to Bexp in multiplication exponent adder 44. Multiplication exponent adder 44 utilizes two extra bits in the most significant places in these
Calculation of the Two-body T-matrix in Configuration Space
Rawitscher, George
2007-01-01
A spectral integral method (IEM) for solving the two-body Schroedinger equation in configuration space is generalized to the calculation of the corresponding T-matrix. It is found that the desirable features of the IEM, such as the economy of mesh-points for a given required accuracy, are carried over also to the solution of the T-matrix. However the algorithm is considerably more complex, because the T-matrix is a function of two variables r and r', rather than only one variable r, and has a slope discontinuity at r=r'. For a simple exponential potential an accuracy of 7 significant figures is achieved, with the number N of Chebyshev support points in each partition equal to 17. For a potential with a large repulsive core, such as the potential between two He atoms, the accuracy decreases to 4 significant figures, but is restored to 7 if N is increased to 65.
DEFF Research Database (Denmark)
Marchalot, Tanguy; Kofoed, Jens Peter; Sørensen, Eigil V.
The objective of the FLOAT project is to study the reliability of high-performance fibre-reinforced concrete, also known as Compact Reinforced Composite (CRC), for the floats of wave energy converters. In order to reach commercial breakthrough, wave energy converters need to achieve a lower price...... of energy produced, comparable to prices currently obtained from offshore wind power, and this can be done by the use of more suitable materials. The flotation device is a key part of converters, as it accounts for a considerable share of initial investment, up to 27% depending on the converter (dexawave.......com, 2011). CRC floats could be a very cost-effective technology with enhanced loading capacity and environmental resistance, and very low maintenance requirements, affecting directly the final energy price. The project involves DEXA Wave Energy Ltd, Wave Star A/S, Aalborg University and Hi-Con A...
Electromagnetic two-body problem: recurrent dynamics in the presence of state-dependent delay
Energy Technology Data Exchange (ETDEWEB)
De Luca, Jayme [Departamento de Fisica, Universidade Federal de Sao Carlos, Caixa Postal 676, Sao Carlos, Sao Paulo 13565-905 (Brazil); Guglielmi, Nicola [Dipartimento di Matematica Pura ed Applicata, Universita degli Studi di L' Aquila, I-67010, L' Aquila (Italy); Humphries, Tony [Department of Mathematics and Statistics, McGill University, Montreal, Quebec H3A 2K6 (Canada); Politi, Antonio, E-mail: deluca@df.ufscar.b [Istituto dei Sistemi Complessi, CNR Via Madonna del Piano 10-Sesto, Fiorentino I-50019 (Italy)
2010-05-21
We study the electromagnetic two-body problem of classical electrodynamics as a prototype dynamical system with state-dependent delays. The equations of motion are analysed with reference to motion along a straight line in the presence of an electrostatic field. We consider the general electromagnetic equations of motion for point charges with advanced and retarded interactions and study two limits, (a) retarded-only interactions (Dirac electrodynamics) and (b) half-retarded plus half-advanced interactions (Wheeler-Feynman electrodynamics). A fixed point is created where the electrostatic field balances the Coulombian attraction, and we use local analysis near this fixed point to derive necessary conditions for a Hopf bifurcation. In case (a), we study a Hopf bifurcation about an unphysical fixed point and find that it is subcritical. In case (b), there is a Hopf bifurcation about a physical fixed point and we study several families of periodic orbits near this point. The bifurcating periodic orbits are illustrated and simulated numerically, by introducing a surrogate dynamical system into the numerical analysis which transforms future data into past data by exploiting the periodicity, thus obtaining systems with only delays.
Electromagnetic two-body problem: recurrent dynamics in the presence of state-dependent delay
De Luca, Jayme; Guglielmi, Nicola; Humphries, Tony; Politi, Antonio
2010-05-01
We study the electromagnetic two-body problem of classical electrodynamics as a prototype dynamical system with state-dependent delays. The equations of motion are analysed with reference to motion along a straight line in the presence of an electrostatic field. We consider the general electromagnetic equations of motion for point charges with advanced and retarded interactions and study two limits, (a) retarded-only interactions (Dirac electrodynamics) and (b) half-retarded plus half-advanced interactions (Wheeler-Feynman electrodynamics). A fixed point is created where the electrostatic field balances the Coulombian attraction, and we use local analysis near this fixed point to derive necessary conditions for a Hopf bifurcation. In case (a), we study a Hopf bifurcation about an unphysical fixed point and find that it is subcritical. In case (b), there is a Hopf bifurcation about a physical fixed point and we study several families of periodic orbits near this point. The bifurcating periodic orbits are illustrated and simulated numerically, by introducing a surrogate dynamical system into the numerical analysis which transforms future data into past data by exploiting the periodicity, thus obtaining systems with only delays.
DEFF Research Database (Denmark)
Tande, John Olav Giæver; Merz, Karl; Schmidt Paulsen, Uwe
2014-01-01
phase applying (mostly) well-known technology, albeit in a new setting. DeepWind is a European research project based mostly on new technology. The concepts are described in some detail with emphasis on control and operation. Prospects are discussed including technical challenges and a performance...... metric of energy production per unit steel mass. Floating offshore wind turbines represent a promising technology. The successful operation of HyWind and WindFloat in full scale demonstrates a well advanced technology readiness level, where further development will go into refining the concepts, cost...
Vella, Dominic
2015-01-01
Small objects that are more dense than water may still float at the air-water interface because of surface tension. Whether this is possible depends not only on the density and size of the object, but also on its shape and surface properties, whether other objects are nearby, and how gently the object is placed at the interface. This review surveys recent work to quantify when objects can float and when they must sink. Much interest in this area has been driven by studies of the adaptations of water-walking insects to life at interfaces. I therefore discuss these results in the context of this and other applications.
Charmless hadronic two-body decays of Bs mesons
Chen, Yaw-Hwang; Cheng, Hai-Yang; Tseng, B.
1999-04-01
Two-body charmless nonleptonic decays of the Bs meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients are μ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of Neffc(LL) and Neffc(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Branching ratios of Bs-->PP,PV,VV decays (P: pseudoscalar meson, V: vector meson) are calculated as a function of Neffc(LR) with two different considerations for Neffc(LL): (a) Neffc(LL) being fixed at the value of 2 and (b) Neffc(LL)=Neffc(LR). Tree and penguin transitions are classified into six different classes. We find the following. (i) The electroweak penguin contributions account for about 85% [for Neffc(LL)=2] of the decay rates of Bs-->ηπ, η'π, ηρ, η'ρ, φπ, φρ, which receive contributions only from tree and electroweak penguin diagrams; a measurement of them will provide a clean determination of the electroweak penguin coefficient a9. (ii) Electroweak penguin corrections to Bs-->ωη('),φη,ωφ,K(*)φ,φφ are in general as significant as QCD penguin effects and even play a dominant role; their decay rates depend strongly on Neffc(LR). (iii) The branching ratio of Bs-->ηη', the analogue of Bd-->η'K, is of order 2×10-5, which is only slightly larger than that of η'η',K*+ρ-,K+K-,K0K¯0 decay modes. (iv) The contribution from the η' charm content is important for Bs-->η'η', but less significant for Bs-->ηη'. (v) The decay rates for the final states K+(*)K-(*) follow the pattern Γ(B¯s-->K+K-)>Γ(B¯s-->K+K*-)>~Γ(B¯s-->K*+K*-)>Γ(B¯s-->K+*K-) and likewise for K0(*)K¯0(*), as a consequence of various interference effects between the penguin amplitudes governed by the effective QCD penguin coefficients a4 and a6.
Tethered float liquid level sensor
Energy Technology Data Exchange (ETDEWEB)
Daily, III, William Dean
2016-09-06
An apparatus for sensing the level of a liquid includes a float, a tether attached to the float, a pulley attached to the tether, a rotation sensor connected to the pulley that senses vertical movement of said float and senses the level of the liquid.
Institute of Scientific and Technical Information of China (English)
刘沛华; 鲁华祥; 龚国良; 刘文鹏
2012-01-01
Many application areas, such as digital communication and image processing, make extensive use of ma-trix multiplication operations, and the computational performance of this operation is critical for the whole system. A parallel double-precision floating-point matrix multiplier with pipeline architecture was designed to improve the computational performance. The design was implemented in a Xilinx Virtex-5 LX155 field programmable gate array ( FPGA). Up to 10 processing elements were integrated in a single FPGA device, and they were arranged as an ar-ray to achieve parallel computation. The processing elements employed pipelined architecture to increase the speed, and C-slow retiming was applied to solve the data-related conflicts issues on the loop pipeline. The post-Route sim-ulation results show that the peak performance of the matrix multiplier can achieve 5 000 MFLOPS. In addition, the matrix multiplication experiments with differenl dimensions were carried out, and the results confirm that the design achieved high computational performance.%在数字通信、图像处理等应用领域中需要用到大量的矩阵乘法运算,并且它的计算性能是影响系统性能的关键因素.设计了一个全流水结构的并行双精度浮点矩阵乘法器以提高计算性能,并在Xilinx Virtex-5 LX155现场可编程门阵列(FPGA)上完成了方案的实现.乘法器中处理单元(PE)按阵列形式排列,在一个FPGA芯片上可集成10个PE单元实现并行计算.为了提高工作频率,PE单元采用流水线结构,并运用C-slow时序重排技术解决了环路流水线上“数据相关冲突”的问题.仿真结果表明,该乘法器的峰值计算性能可达到5000 MFLOPS.此外,对不同维数的矩阵乘法进行了实验,其结果也证实了该设计达到了较高的计算性能.
Rivera, R.; Villarroel, D.
1997-11-01
An exactly solvable two-body problem dealing with the Lorentz-Dirac equation is constructed in this paper. It corresponds to the motion of two identical charges rotating at opposite ends of a diameter, in a fixed circle, at constant angular velocity. The external electromagnetic field that allows this motion consists of a tangential time-independent electric field with a fixed value over the orbit circle, and a homogeneous time-independent magnetic field that points orthogonally to the orbit plane. Because of the geometrical symmetries of the charges' motion, in this case it is possible to obtain the rate of radiation emitted by the charges directly from the equation of motion. The rate of radiation is also calculated by studying the energy flux across a sphere of a very large radius, using the far retarded fields of the charges. Both calculations lead to the same result, in agreement with energy conservation.
Institute of Scientific and Technical Information of China (English)
黄立波; 王志英; 沈立; 马胜
2012-01-01
SIMD单元集成已经成为提高处理器性能的重要途径之一.虽然定点SIMD单元的硬件复用低成本设计技术已经较为成熟,但是,大部分浮点SIMD单元的硬件设计还停留在简单的硬件复制方法上.本文针对日益增长的128位高精度浮点操作的计算需求,提出了其相应的SIMD低成本硬件结构方案.综合实验结果表明,所提出的SIMD浮点乘加单元比传统128位高精度浮点乘加单元具有更加优化的性能与面积参数.%Incorporating the SIMD unit has become one of the important ways to improve the performance of processors. The reused low-cost hardware design method for the fixed-point SIMD unit is mature,but it is not the case for the floating-point SIMD unit,which still remains the simple replication design method. To address the increasing computation demand for 128 — bit quadruple-precision floatingpoint operations, this paper proposes the hardware design of the low-cost 128-bit quadruple-precision floating-point SIMD fused multiply-add (FMA) unit. The experimental results show that the structure of the proposed FMA unit can be more optimized in performance and cost parameters in comparison to the traditional 128-bit quadruple-precision floating-point SIMD multiple-add unit.
Float processing of high-temperature complex silicate glasses and float baths used for same
Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)
2000-01-01
A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.
2003-08-15
REVIEW, 83-89 Int. Hydrogr. Rev., 1986 ARANHA , JAP PESCE, CP, EFFECT OF THE 2ND-ORDER POTENTIAL IN THE SLOW-DRIFT OSCILLATION OF A FLOATING STRUCTURE...Technology Conference, Annual Proceedings, v 3, Construction & Installation/Field Drilling and Development Systems, 1997, OTC 8696, p 133-142 Aranha , J...Andre J.P. (Petrobras/Depro); Nishimoto, Kazuo; Aranha , J.A.P.; Morooka, Celso K., Minimization of vertical wave exciting force and heave motion of a
PERANCANGAN FLOATING DOCK UNTUK DAERAH PERAIRAN PELABUHAN KOTA TEGAL
Directory of Open Access Journals (Sweden)
Kiryanto Kiryanto
2013-06-01
Full Text Available Floating dock merupakan bangunan air sebagai tempat reparasi kapal yang dinilai cukup efisien dalam pembangunannya karena tidak membutuhkan dana yang terlalu mahal. Di sektor indusrti perkapalan kota tegal sudah memiliki galangan dan dock reparasi kapal yang cukup berkembang. Ide perancangan floating dock ini dirancang sebagai alternatif baru pelayanan reparasi kapal. Perancangan floating dock ini juga memperhatikan dengan detail kapasitas kapal – kapal yang pernah melakukan repararasi di sekitar galangan di Kota Tegal agar ditemukan ukuran utama floating dock yang tepat. Dari Kapasitas kapal yang ada dan berdasarkan metode perbandingan ukuran beberapa floating dock, maka ditemukan ukuran utama yang tepat untuk menampung kebutuhan pelayanan reparasi kapal yaitu LOA = 136,37 m, Lpt = 114.80 m, Bmax = 36,40 m, Bmd: 30,80 m, Tmin = 0,86 m, Tmax = 1,58 m, Hpt = 2,10 m, HOA = 9,60 m. Berdasarkan perhitungan ditemukan juga Ton Lifting Capacity (TLC sebesar 3000 ton. Perancangan menggunakan software perkapalan yaitu dengan menggunakan AutoCad, Delftship, Maxsurf dan Hidromax. Dengan analisa stabilitas menggunakan software Hidromax diketahui bahwa floating dock ini mampu memiliki stabilitas yang baik dengan 4 kondisi yang semua memenuhi criteria International Maritime Organisation (IMO. Perancangan floating dock ini juga menghitung analisa ekonomis dan investasi. Dari rekapitulasi dana investasi pembangunan floating dock yaitu sebesar Rp.136.622.888.000,00 dengan nilai kembali atau break even point selama 10 tahun dengan modal sendiri, 14 tahun dengan 50% modal sendiri dan 50 % pinjaman bank, dan break event point 18 tahun untuk dana pembangunan floating dock yang berasal dari 100 % pinjaman bank
Two-body wear of dental porcelain and substructure oxide ceramics.
Rosentritt, Martin; Preis, Verena; Behr, Michael; Hahnel, Sebastian; Handel, Gerhard; Kolbeck, Carola
2012-06-01
The aim of this in vitro study was to investigate the two-body wear of different ceramics. Two-body wear tests were performed in a chewing simulator with steatite and enamel antagonists, respectively. Specimens were loaded in a pin-on-block design with a vertical load of 50 N for 1.2 × 10(5) cycles; (f = 1.6 Hz; lateral movement, 1 mm; mouth opening: 2 mm). Human enamel was used as a reference. Three zirconia ceramics, three veneering porcelains, two glass-infiltrated and one lithium disilicate ceramic were investigated. Veneering and lithium disilicate ceramics were glazed before testing. Surface roughness Ra (SP6, Perthen-Feinprüf, G) and wear depth were determined using a 3D scanner (Laserscan 3D, Willytec, G). SEM (Quanta FEG 400, FEI, USA) pictures of the worn specimens and antagonists were made for evaluating wear performance. Veneering porcelain provided wear traces between 71.2 and 124.1 μm (enamel antagonist) and 117.4 and 274.1 μm (steatite). Wear of the steatite antagonists varied between 0.618 and 2.85 mm². No wear was found for zirconia and glass-infiltrated substructure ceramics. Also, no wear was found for the corresponding antagonists. Wear of specimens and antagonists was strongly material dependent. No visible wear was found on zirconia and glass-infiltrated ceramics. Porcelain and lithium disilicate ceramic showed a comparable or lower wear than the enamel reference. Antagonist wear was found to be lower when specimens were made of substructure oxide ceramics instead of veneering porcelain. From the point of wear testing, zirconia may be used for the fabrication of fixed dental prosthesis without veneering.
Energy Technology Data Exchange (ETDEWEB)
George, J.E.
1975-09-01
Three algorithms are presented as a set of Standard Fortran subroutines which compute the number of characters representable in a single storage unit, the number of bits representing a character, and the type of integer representation. This information provides for the determination of a lower bound for the floating-point exponent length. The method used for the computations is rarely discussed in the literature of programing techniques and is applicable to other languages. The assumptions of the algorithm and the accuracy of the results are discussed. 1 table.
Study on Floating Properties and Stability of Air Floated Structures
Institute of Scientific and Technical Information of China (English)
别社安; 及春宁; 任增金; 李增志
2002-01-01
In this paper, the buoyancy, kinetic properties and stability of air floated structures have been studied by theoreticaland experimental methods. The equations for calculation of the buoyancy of the air floated buoy are derived according tothe Boyler law and the equilibrium equations of the air floated structure are established. Through simplification of the airfloated structure as a single freedom rigid body and spring system, the natural period of heaving and some kinetic proper-ties are discussed. In the stability analysis, the formulas for calculation of the meta centric height are presented. The the-oretical results are in good agreement with the data observed from the model test and prototype test. The air buoyancy de-crease coefficient presented in this paper has a large influence on the floating state, stability and dynamic properties of theair floated structure. The stability of the air floated structure can also be judged by the parameter of meta centric height,and calculations show that the air floated structure is less stable than the conventional float.
Bossard, Guillaume
2014-01-01
We define a new partially solvable system of equations that parametrises solutions to six-dimensional N=(1,0) ungauged supergravity coupled to tensor multiplets. We obtain this system by applying a series of dualities on the known floating brane system, imposing that it allows for the JMaRT solution. We construct an explicit multi-centre solution generalising the JMaRT solution, with an arbitrary number of additional BPS centres on a line. We describe explicitly the embedding of the JMaRT solution in this system in five dimensions.
Low Noise Bias Current/Voltage References Based on Floating-Gate MOS Transistors
DEFF Research Database (Denmark)
Igor, Mucha
1997-01-01
The exploitation of floating-gate MOS transistors as reference current and voltage sources is investigated. Test structures of common source and common drain floating-gate devices have been implemented in a commercially available 0.8 micron double-poly CMOS process. The measurements performed...... promise a good maintenance of the operating point of the floating-gate devices. Examples of utilizing of such bias sources in low-noise sensor preamplifiers are discussed....
Low Noise Bias Current/Voltage References Based on Floating-Gate MOS Transistors
DEFF Research Database (Denmark)
Igor, Mucha
1997-01-01
The exploitation of floating-gate MOS transistors as reference current and voltage sources is investigated. Test structures of common source and common drain floating-gate devices have been implemented in a commercially available 0.8 micron double-poly CMOS process. The measurements performed...... promise a good maintenance of the operating point of the floating-gate devices. Examples of utilizing of such bias sources in low-noise sensor preamplifiers are discussed....
Heng, Kenneth
2016-01-01
“Floating shoulder” is a rare injury complex resulting from high-energy blunt force trauma to the shoulder, resulting in scapulothoracic dissociation. It is commonly associated with catastrophic neurovascular injury. Two cases of motorcyclists with floating shoulder injuries are described.
Floating microspheres: a review
Directory of Open Access Journals (Sweden)
Jagtap Yogesh Mukund
2012-03-01
Full Text Available Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter- and intra-subject variability of gastro-intestinal (GI transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI e
Smallness of tree-dominated charmless two-body baryonic B decay rates
Cheng, Hai-Yang; Chua, Chun-Khiang
2015-02-01
The long-awaited baryonic B decay B¯0→p p ¯ was recently observed by LHCb with a branching fraction of order 1 0-8. All the earlier model predictions are too large compared with experiment. In this work, we point out that for a given tree operator Oi, the contribution from its Fiertz transformed operator, an effect often missed in the literature, tends to cancel the internal W -emission amplitude induced from Oi. The wave function of low-lying baryons is symmetric in momenta and the quark flavor with the same chirality but antisymmetric in color indices. Using these symmetry properties and the chiral structure of weak interactions, we find that half of the Feynman diagrams responsible for internal W emission cancel. Since this feature holds in the charmless modes but not in the charmful ones, we advocate that the partial cancellation accounts for the smallness of the tree-dominated charmless two-body baryonic B decays. This also explains why most previous model calculations predicted too large rates as the above consideration was not taken into account. Finally, we emphasize that, contrary to the claim in the literature, the internal W -emission tree amplitude should be proportional to the Wilson coefficient c1+c2 rather than c1-c2.
On the smallness of Tree-dominated Charmless Two-body Baryonic $B$ Decay Rates
Cheng, Hai-Yang
2014-01-01
The long awaited baryonic $B$ decay $\\bar B{}^0\\to p\\bar p$ was recently observed by LHCb with a branching fraction of order $10^{-8}$. All the earlier model predictions are too large compared with experiment. In this work, we point out that for a given tree operator $O_i$, the contribution from its Fiertz transformed operator, an effect often missed in the literature, tends to cancel the internal $W$-emission amplitude induced from $O_i$. The wave function of low-lying baryons are symmetric in momenta and the quark flavor with the same chirality, but antisymmetric in color indices. Using these symmetry properties and the chiral structure of weak interactions, we find that half of the Feynman diagrams responsible for internal $W$-emission cancel. Since this feature holds in the charmless modes but not in the charmful ones, we advocate that the partial cancellation accounts for the smallness of the tree-dominated charmless two-body baryonic $B$ decays. This also explains why most previous model calculations pr...
Two-body and three-body contacts for identical Bosons near unitarity.
Smith, D Hudson; Braaten, Eric; Kang, Daekyoung; Platter, Lucas
2014-03-21
In a recent experiment with ultracold trapped Rb85 atoms, Makotyn et al. studied a quantum-degenerate Bose gas in the unitary limit where its scattering length is infinitely large. We show that the observed momentum distributions are compatible with a universal relation that expresses the high-momentum tail in terms of the two-body contact C2 and the three-body contact C3. We determine the contact densities for the unitary Bose gas with number density n to be C2 ≈ 20 n(4/3) and C3 ≈ 2n(5/3). We also show that the observed atom loss rate is compatible with that from 3-atom inelastic collisions, which gives a contribution proportional to C3, but the loss rate is not compatible with that from 2-atom inelastic collisions, which gives a contribution proportional to C2. We point out that the contacts C2 and C3 could be measured independently by using the virial theorem near and at unitarity, respectively.
Sekihara, Takayasu
2016-01-01
For a general two-body bound state in quantum mechanics, both in the stable and decaying cases, we establish a way to extract its two-body wave function in momentum space from the scattering amplitude of the constituent two particles. For this purpose, we first show that the two-body wave function of the bound state corresponds to the residue of the off-shell scattering amplitude at the bound state pole. Then, we examine our scheme to extract the two-body wave function from the scattering amplitude in several schematic models. As a result, the two-body wave functions from the Lippmann--Schwinger equation coincides with that from the Schr\\"{o}dinger equation for an energy-independent interaction. Of special interest is that the two-body wave function from the scattering amplitude is automatically scaled; the norm of the two-body wave function, to which we refer as the compositeness, is unity for an energy-independent interaction, while the compositeness deviates from unity for an energy-dependent interaction, ...
Energy Technology Data Exchange (ETDEWEB)
Kellerman, Peter
2013-12-21
The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.
Neutrally floating objects of density 1/2 in three dimensions
Várkonyi, Péter L
2012-01-01
This paper is concerned with the Floating Body Problem of S. Ulam: the existence of objects other than the sphere, which can float in a liquid in any orientation. Despite recent results of F. Wegner pointing towards an affirmative answer, a full proof of their existence is still unavailable. For objects with cylindrical symmetry and density 1/2, the conditions of neutral floating are formulated as an initial value problem, for which a unique solution is predicted in certain cases by a suitable generalization of the Picard-Lindel\\"of theorem. Numerical integration of the initial value problem provides a rich variety of neutrally floating shapes.
Matrix Elements of One- and Two-Body Operators in the Unitary Group Approach (II) - Application
Institute of Scientific and Technical Information of China (English)
DAI Lian-Rong; PAN Feng
2001-01-01
Simple analytical expressions for one- and two-body matrix elements in the unitary group approach to the configuration interaction problems of many-electron systems are obtained based on the previous results for general Un irreps.
Electrically floating, near vertical incidence, skywave antenna
Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.
2014-07-08
An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.
Large floating structures technological advances
Wang, BT
2015-01-01
This book surveys key projects that have seen the construction of large floating structures or have attained detailed conceptual designs. This compilation of key floating structures in a single volume captures the innovative features that mark the technological advances made in this field of engineering, and will provide a useful reference for ideas, analysis, design, and construction of these unique and emerging urban projects to offshore and marine engineers, urban planners, architects and students.
Viterna, Larry A. (Inventor)
2009-01-01
A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.
Artisanal fishing net float loss and a proposal for a float design solution
Directory of Open Access Journals (Sweden)
Paulo de Tarso Chaves
2016-03-01
Full Text Available Abstract Plastic floats from fishing nets are commonly found washed up on beaches in southern Brazil. They are usually broken and show signs of having been repaired. Characteristics of floats and interviews with fishermen suggest two main causes of float loss. First, collisions between active gear, bottom trawl nets for shrimp, and passive gear, drift nets for fish, destroy nets and release fragments of them, including floats. Second, the difficulty with which floats are inserted on the float rope of the nets when they are used near the surface. Floats are inserted to replace damaged or lost floats, or they may be removed if it is desired that the nets be used in deeper waters. Floats may thus be poorly fixed to the cables and lost. Here a new float design that offers greater safety in use and for the replacement of floats is described and tested.
Relativistic two-body bound states in scalar QFT: variational basis-state approach
Energy Technology Data Exchange (ETDEWEB)
Emami-Razavi, Mohsen [Centre for Research in Earth and Space Science, York University, Toronto, Ontario, M3J 1P3 (Canada); Darewych, Jurij W [Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3 (Canada)
2006-08-15
We use the Hamiltonian formalism of quantum field theory and the variational basis-state method to derive relativistic coupled-state wave equations for scalar particles interacting via a massive or massless mediating scalar field (the scalar Yukawa model). A variational trial state comprised of two and four Fock-space states is used to derive coupled wave equations for a relativistic two (and four) body system. Approximate, variational two-body ground-state solutions of the relativistic equations are obtained for various strengths of coupling, for both massive and massless mediating fields. The results show that the inclusion of virtual pairs has a large effect on the two-body binding energy at strong coupling. A comparison of the two-body binding energies with other calculations is presented.
Floating Cities, Islands and States
Bolonkin, Alexander
2008-01-01
Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating c...
Analytical treatment of the two-body problem with slowly varying mass
Rahoma, W. A.; Abd El-Salam, F. A.; Ahmed, M. K.
2009-12-01
The present work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.
Spin Structure of Many-Body Systems with Two-Body Random Interactions
Kaplan, L; Johnson, C W; Kaplan, Lev; Papenbrock, Thomas; Johnson, Calvin W.
2001-01-01
We investigate the spin structure of many-fermion systems with a spin-conserving two-body random interaction. We find a strong dominance of spin-0 ground states and considerable correlations between energies and wave functions of low-lying states with different spin, but no indication of pairing. The spectral densities exhibit spin-dependent shapes and widths, and depend on the relative strengths of the spin-0 and spin-1 couplings in the two-body random matrix. The spin structure of low-lying states can largely be explained analytically.
Exact two-body solutions and quantum defect theory of two-dimensional dipolar quantum gas
Jie, Jianwen; Qi, Ran
2016-10-01
In this paper, we provide the two-body exact solutions of the two-dimensional (2D) Schrödinger equation with isotropic +/- 1/{r}3 interactions. An analytic quantum defect theory is constructed based on these solutions and it is applied to investigate the scattering properties as well as two-body bound states of an ultracold polar molecules confined in a quasi-2D geometry. Interestingly, we find that for the attractive case, the scattering resonance happens simultaneously in all partial waves, which has not been observed in other systems. The effect of this feature on the scattering phase shift across such resonances is also illustrated.
Analytical expressions for partial wave two-body Coulomb transition matrices at ground-state energy
Kharchenko, V. F.
2016-11-01
Leaning upon the Fock method of the stereographic projection of the three-dimensional momentum space onto the four-dimensional unit sphere the possibility of the analytical solving of the Lippmann-Schwinger integral equation for the partial wave two-body Coulomb transition matrix at the ground bound state energy has been studied. In this case new expressions for the partial p-, d- and f-wave two-body Coulomb transition matrices have been obtained in the simple analytical form. The developed approach can also be extended to determine analytically the partial wave Coulomb transition matrices at the energies of excited bound states.
Analytical Treatment of the Two-Body Problem with Slowly Varying Mass
Indian Academy of Sciences (India)
W. A. Rahoma; F. A. Abd El-Salam; M. K. Ahmed
2009-09-01
The present work is concerned with the two-body problem with varying mass in case of isotropic mass loss from both components of the binary systems. The law of mass variation used gives rise to a perturbed Keplerian problem depending on two small parameters. The problem is treated analytically in the Hamiltonian frame-work and the equations of motion are integrated using the Lie series developed and applied, separately by Delva (1984) and Hanslmeier (1984). A second order theory of the two bodies eject mass is constructed, returning the terms of the rate of change of mass up to second order in the small parameters of the problem.
Neutral weak-current two-body contributions in inclusive scattering from {sup 12}C
Energy Technology Data Exchange (ETDEWEB)
Lovato, Alessandro [ANL; Gandolfi, Stefano [LANL; Carlson, Joseph [LANL; Pieper, S. C. [ANL; Schiavilla, Rocco [JLAB, ODU
2014-05-01
An {\\it ab initio} calculation of the sum rules of the neutral weak response functions in $^{12}$C is reported, based on a realistic Hamiltonian, including two- and three-nucleon potentials, and on realistic currents, consisting of one- and two-body terms. We find that the sum rules of the response functions associated with the longitudinal and transverse components of the (space-like) neutral current are largest and that a significant portion ($\\simeq 30$\\%) of the calculated strength is due to two-body terms. This fact may have implications for the MiniBooNE and other neutrino quasi-elastic scattering data on nuclei.
Energy Technology Data Exchange (ETDEWEB)
Kijima, K.; Murata, W.; Furukawa, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering
1997-10-01
The control system for keeping the fixed-point of ships against disturbance was designed by applying an ILQ (Inverse Linear Quadratic) control (possible to specify the response of controlled systems with time constant) theory, to study the effect of different time constants as design parameter on a fixed-point keeping performance. It was assumed that the controlled ship is equipped with two bow thrusters and one stern thruster of 30ton in output to generate a control force. For fixed-point keeping control, the state equation was derived to slave the controlled system to a target input. The ILQ design method uses the result of the inverse problem of optimum regulators. For designing control systems by using the ILQ control theory, the smallest time constant should be selected according to the most severe disturbance condition considering the response performance of controllers, to achieve fixed-point keeping of ships. In fixed-point keeping, it is also essential to put the initial position as close as possible to the target point. 2 refs., 6 figs., 2 tabs.
Critical Point Dryer: Tousimis 916B Series C
Federal Laboratory Consortium — Description: CORAL Name: Critical Point Dryer This system utilizes CO 2to dry fragile suspended and floating structures Specifications / Capabilities: Wafer size up...
Realization of the Fredkin gate using a series of one- and two-body operators
Chau, H F; Chau, Hoi Fung; Wilczek, F
1995-01-01
The Fredkin 3-bit gate is universal for computational logic, and is reversible. Classically, it is impossible to do universal computation using reversible 2-bit gates only. Here we construct the Fredkin gate using a combination of two one-body and seven two-body reversible (quantum) operators.
Computation of Two-Body Matrix Elements From the Argonne $v_{18}$ Potential
Mihaila, B; Mihaila, Bogdan; Heisenberg, Jochen H.
1998-01-01
We discuss the computation of two-body matrix elements from the Argonne $v_{18}$ interaction. The matrix elements calculation is presented both in particle-particle and in particle-hole angular momentum coupling. The procedures developed here can be applied to the case of other NN potentials, provided that they have a similar operator format.
Two-body depolarized cils spectra of krypton and xenon at 295 K
Zoppi, M.; Moraldi, M.; Barocchi, F.; Magli, R.; Bafile, U.
1981-10-01
We have experimentally determined the two-body depolarized CILS spectra of krypton and xenon at room temperature between 2 and 120 cm-1. Comparison of the first three even experimental moments of the spectra with theoretical calculations shows, as in argon, the necessity of introducing a short-range negative contribution to the induced pair polarizability.
78 FR 54756 - Extension of Expiration Dates for Two Body System Listings
2013-09-06
... ADMINISTRATION 20 CFR Part 404 RIN 0960-AH60 Extension of Expiration Dates for Two Body System Listings AGENCY: Social Security Administration. ACTION: Final rule. SUMMARY: We are extending the expiration dates of the... claims and continuing disability reviews. DATES: This final rule is effective on September 6, 2013....
Searching for new physics in two-body decays: Ideas and pitfalls
Arrieta Diaz, E; Büchler, A; Cieri, L J; Florez, A; Garces-Garcia, E; Gonçalves, B; Koetsveld, F; Leney, K J C; Marquez Falcon, H; Moncada, M; Quintero, P; Romero, D; Shaw, K; Swain, J; Zurita, M P
2010-01-01
Many new physics processes, and indeed many Standard Model interactions involve two-body decays. Although the kinematics are relatively simple, mistakes can easily be made when applying cuts to data in order to separate the signal from backgrounds. We present a short, but relevant list of possible sources of errors, and discuss the consequences of these.
Two-body physics in the Su-Schrieffer-Heeger model
Di Liberto, M.; Recati, A.; Carusotto, I.; Menotti, C.
2016-12-01
We consider two interacting bosons in a dimerized Su-Schrieffer-Heeger (SSH) lattice. We identify a rich variety of two-body states. In particular, for open boundary conditions and moderate interactions, edge bound states (EBS) are present even for the dimerization that does not sustain single-particle edge states. Moreover, for large values of the interactions, we find a breaking of the standard bulk-boundary correspondence. Based on the mapping of two interacting particles in one dimension onto a single particle in two dimensions, we propose an experimentally realistic coupled optical fibers setup as quantum simulator of the two-body SSH model. This setup is able to highlight the localization properties of the states as well as the presence of a resonant scattering mechanism provided by a bound state that crosses the scattering continuum, revealing the closed-channel population in real time and real space.
Distribution of level spacing ratios using one- plus two-body random matrix ensembles
Indian Academy of Sciences (India)
N D Chavda
2015-02-01
Probability distribution (()) of the level spacing ratios has been introduced recently and is used to investigate many-body localization as well as to quantify the distance from integrability on finite size lattices. In this paper, we study the distribution of the ratio of consecutive level spacings using one-body plus two-body random matrix ensembles for finite interacting many-fermion and many-boson systems. () for these ensembles move steadily from the Poisson to the Gaussian orthogonal ensemble (GOE) form as the two-body interaction strength is varied. Other related quantities are also used in the analysis to obtain critical strength c for the transition. The c values deduced using the () analysis are in good agreement with the results obtained using the nearest neighbour spacing distribution (NNSD) analysis.
The two-body problem of a pseudo-rigid body and a rigid sphere
DEFF Research Database (Denmark)
Kristiansen, Kristian Uldall; Vereshchagin, M.; Gózdziewski, K.;
2012-01-01
n this paper we consider the two-body problem of a spherical pseudo-rigid body and a rigid sphere. Due to the rotational and "re-labelling" symmetries, the system is shown to possess conservation of angular momentum and circulation. We follow a reduction procedure similar to that undertaken...... in the study of the two-body problem of a rigid body and a sphere so that the computed reduced non-canonical Hamiltonian takes a similar form. We then consider relative equilibria and show that the notions of locally central and planar equilibria coincide. Finally, we show that Riemann's theorem on pseudo......-rigid bodies has an extension to this system for planar relative equilibria....
CP Violating Polarization Asymmetry in Charmless Two-Body Decays of Beauty Baryons
He, Min; Li, Guan-Nan
2015-01-01
Several baryons containing a heavy b-quark, the b-baryons, have been discovered. The charmless two-body decays of b-baryons can provide a new platform for CP violating studies in a similar way as charmless two-body decays of B-meson. In b-baryon decays there are new CP violating observable related to baryon polarization. We show that in the flavor $SU(3)$ limit there exist relations involve different combinations of the decay amplitudes compared with those in CP violating rate asymmetry. These new relations therefore provide interesting tests for the mechanism of CP in the standard model (SM) and flavor $SU(3)$ symmetry. Future data from LHCb can test these relations.
Energy Centroids of Spin $I$ States by Random Two-body Interactions
Zhao, Y M; Ogawa, K
2005-01-01
In this paper we study the behavior of energy centroids (denoted as $\\bar{E_I}$) of spin $I$ states in the presence of random two-body interactions, for systems ranging from very simple systems (e.g. single-$j$ shell for very small $j$) to very complicated systems (e.g., many-$j$ shells with different parities and with isospin degree of freedom). Regularities of $\\bar{E_I}$'s discussed in terms of the so-called geometric chaoticity (or quasi-randomness of two-body coefficients of fractional parentage) in earlier works are found to hold even for very simple systems in which one cannot assume the geometric chaoticity. It is shown that the inclusion of isospin and parity does not "break" the regularities of $\\bar{E_I}$'s.
A Tale of Three Equations Breit, Eddington-Guant, and Two-Body Dirac
Van Alstine, P; Alstine, Peter Van; Crater, Horace W.
1997-01-01
G.Breit's original paper of 1929 postulates the Breit equation as a correction to an earlier defective equation due to Eddington and Gaunt, containing a form of interaction suggested by Heisenberg and Pauli. We observe that manifestly covariant electromagnetic Two-Body Dirac equations previously obtained by us in the framework of Relativistic Constraint Mechanics reproduce the spectral results of the Breit equation but through an interaction structure that contains that of Eddington and Gaunt. By repeating for our equation the analysis that Breit used to demonstrate the superiority of his equation to that of Eddington and Gaunt, we show that the historically unfamiliar interaction structures of Two-Body Dirac equations (in Breit-like form) are just what is needed to correct the covariant Eddington Gaunt equation without resorting to Breit's version of retardation.
Floating Charge%Floating Charge--浮动抵押
Institute of Scientific and Technical Information of China (English)
鲍为民
2004-01-01
"Floating Charge"来源于英美法系,它将担保设立在公司的全部财产之上(该担保甚至可及于公司未来之财产),在结晶前公司对财产享有处分权.通过介绍Floating Charge的创立和发展变化,从设定和实施两个方面详细考察了该制度的具体内涵.最后通过和大陆法系财团抵押制度的对比,提出应在我国引进浮动抵押,完善企业担保制度.
Large-j Expansion Method for Two-Body Dirac Equation
Directory of Open Access Journals (Sweden)
Askold Duviryak
2006-02-01
Full Text Available By using symmetry properties, the two-body Dirac equation in coordinate representation is reduced to the coupled pair of radial second-order differential equations. Then the large-j expansion technique is used to solve a bound state problem. Linear-plus-Coulomb potentials of different spin structure are examined in order to describe the asymptotic degeneracy and fine splitting of light meson spectra.
Two bodies gravitational system with variable mass and damping-antidamping effect due to star wind
López, G V
2009-01-01
We study two-bodies gravitational problem where the mass of one of the bodies varies and suffers a damping-antidamping effect due to star wind during its motion. A constant of motion, a Lagrangian and a Hamiltonian are given for the radial motion of the system, and the period of the body is studied using the constant of motion of the system. An application to the comet motion is given, using the comet Halley as an example.
Kinematics of τ two-body decay near τ threshold at BESⅢ
Institute of Scientific and Technical Information of China (English)
莫晓虎
2010-01-01
The kinematic properties of two-body decay near τ threshold are studied according to the special capacity of the BEPC accelerator and the BESⅢ detector.Explicitly presented are the transformations of energy and momentum of hadronic particles between different reference frames,and the corresponding distributions.A brand new method is proposed to obtain the energy spread of the accelerator by fitting the energy distribution of hadron from τ semi-leptonic decays.
Regularities of many-body systems interacting by a two-body random ensemble
Energy Technology Data Exchange (ETDEWEB)
Zhao, Y.M. [Department of Physics, Shanghai Jiao-Tong University, Shanghai 200030 (China) and Cyclotron Center, Institute of Physical and Chemical Research - RIKEN, Hirosawa 2-1, Wako-shi, Saitama 351-0198 (Japan) and Department of Physics, Southeast University, Nanjing 210018 (China)]. E-mail: ymzhao@riken.jp; Arima, A. [Science Museum, Japan Science Foundation, 2-1 Kitanomaru-Koen, Chiyodaku, Tokyo 102-0091 (Japan); Yoshinaga, N. [Department of Physics, Saitama University, Saitama 338-0625 (Japan)
2004-10-01
The ground states of all even-even nuclei have angular momentum, I, equal to zero, I=0, and positive parity, {pi}=+. This feature was believed to be a consequence of the attractive short-range interaction between nucleons. However, in the presence of two-body random interactions, the predominance of I{pi}=0+ ground states (0 g.s.) was found to be robust both for bosons and for an even number of fermions. For simple systems, such as d bosons, sp bosons, sd bosons, and a few fermions in single-j shells for small j, there are a few approaches to predict and/or explain spin I ground state (I g.s.) probabilities. An empirical approach to predict I g.s. probabilities is available for general cases, such as fermions in a single-j (j>72) or many-j shells and various boson systems, but a more fundamental understanding of the robustness of 0 g.s. dominance is still out of reach. Further interesting results are also reviewed concerning other robust phenomena of many-body systems in the presence of random two-body interactions, such as the odd-even staggering of binding energies, generic collectivity, the behavior of average energies, correlations, and regularities of many-body systems interacting by a displaced two-body random ensemble.
Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure
Directory of Open Access Journals (Sweden)
Taro Kakinuma
2012-01-01
Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.
Validation of Proposed Metrics for Two-Body Abrasion Scratch Test Analysis Standards
Street, Kenneth W., Jr.; Kobrick, Ryan L.; Klaus, David M.
2013-01-01
Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two interacting materials. Knowing the abrasive nature of an environment (abrasive)/construction material is crucial to designing durable equipment for use in such surroundings. The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed Zone of Interaction (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width. The ZOI has been found to be at least twice the size of a standard width measurement; in some cases, considerably greater, indicating that at least half of the disturbed surface area would be neglected without this insight. The ZOI is used to calculate a more robust data set of volume measurements that can be used to computationally reconstruct a resultant profile for de tailed analysis. Documenting additional changes to various surface roughness par ameters also allows key material attributes of importance to ultimate design applications to be quantified, such as depth of penetration and final abraded surface roughness. Further - more, by investigating the use of custom scratch tips for specific needs, the usefulness of having an abrasion metric that can measure the displaced volume in this standardized
Institute of Scientific and Technical Information of China (English)
1995-01-01
AS I walk toward the autumn of my life, I begin to realize that everything in the world seems to have moved in a cycle, like the four seasons that continue to change and renew outside my window. But I am still seated in front of my window, observing the floating clouds at the ends of the earth. Some of them float from the future, some from the past. They join at the head and the tail of the universe; it is hard to tell the dragon’s head from the dragon’s tail. Things are always like this—the beginnings and the endings are sometimes interchangeable; the things that you think have gone by, have gone far away or completely vanished will suddenly appear before you like old acquaintances. Perhaps it might be the second generation accompanied by the shadows of the first.
Floating VAWT wind farm concepts
Schmidt Paulsen, Uwe; Friis Pedersen, Troels; Vita, Luca
2008-01-01
The report contains proposals and descriptions of VAWTs of 200kW, 1MW, 5MW and 25MW sizes in terms of dimensions, weights, loads, and power production. Additionally a proposal of the use of each of these sizes in a concept description for a 100MW wind farm. Manufacture, transportation, installation, maintenance and operation of VAWTs are considered briefly. A summary on advantages and disadvantages of floating VAWTs is given.
Thickness monitor for floated sludge
Energy Technology Data Exchange (ETDEWEB)
Ricketts, J.; Grecu, G.M.
1989-10-31
This patent describes apparatus for determining the thickness of a layer of aerated sludge floating on a layer of a heavier liquid in a tank. It comprises: a frame means which can be positioned to extend vertically into the tank; horizontally-extending indicator means supported by and moveable vertically with respect to a portion of the frame means extending vertically into the tank. The indicator means being selectively positionable at the highest level of sludge in the tank; horizontally-extending lower base means attached to the frame means at or near the bottom thereof; horizontally-extending upper base means attached to the frame means at or near the top thereof; and a line carrying a float means. The line being movable secured at the upper base means and the lower base means. The float means being floatable on the liquid and including a horizontally-extending portion presenting an upwardly directed generally planar surface, which surface will be parallel to the interface of the sludge and liquid.
14 CFR 27.753 - Main float design.
2010-01-01
... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 27.753 Section...
14 CFR 29.753 - Main float design.
2010-01-01
... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats. Each bag float must be designed to withstand— (1) The maximum pressure differential... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 29.753 Section...
Vandendriessche, S.; Messiaen, M.; O'Flynn, S; M. Vincx; Degraer, S.
2007-01-01
Floating seaweed is considered to be an important habitat for juvenile fishes due to the provision of food, shelter, a visual orientation point and passive transport. The importance of the presence of the highly dynamical seaweed clumps from the North Sea to juvenile neustonic fishes was investigated by analysing both neuston samples (without seaweed) and seaweed samples concerning fish community structure, and length-frequency distributions and feeding habits of five associated fish species....
The post-Keplerian orbital representations of the relativistic two-body problem
Klioner, S. A.; Kopeikin, S. M.
1994-06-01
Orbital parameterizations of the relativstic two-body problem due to Brumberg, Damour-Deruelle, Epstein-Haugan, and Blandford-Teukolsky as well as osculating elements are compared. Exact relations between constants describing the orbit in the parameterizations are derived. It is shown that all the parameterizations in question are valid not only in general relativity, but in a generic class of relatvistic theories of gravity. The obtained results provide us with an additional check of consistency of different models used in timing of binary pulsars.
On the change of density of states in two-body interactions
Gao, Bo
2016-01-01
We derive a general relation in two-body scattering theory that more directly relates the change of density of states (DDOS) due to interaction to the shape of the potential. The relation allows us to infer certain global properties of the DDOS from the global properties of the potential. In particular, we show that DDOS is negative at all energies and for all partial waves, for potentials that are more repulsive than $+1/r^2$ everywhere. This behavior represents a different class of global properties of DDOS from that described by the Levinson's theorem.
Probing SUSY CP Violation in Two-Body Stop Decays at the LHC
Deppisch, Frank
2009-01-01
We study CP asymmetries in two-body decays of top squarks into neutralinos and sleptons at the LHC. These asymmetries are used to probe the CP phases possibly present in the stop and neutralino sector of the Minimal Supersymmetric Standard Model. Taking into account bounds from experimental electric dipole moment searches, we identify areas in the mSUGRA parameter space where CP asymmetries can be sizeable and discuss the feasibility of their observation at the LHC. As a result, potentially detectable CP asymmetries in stop decays at the LHC are found, motivating further detailed experimental studies for probing SUSY CP phases.
The two-body random spin ensemble and a new type of quantum phase transition
Energy Technology Data Exchange (ETDEWEB)
Pizorn, Iztok; Prosen, Tomaz [Department of Physics, FMF, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Mossmann, Stefan; Seligman, Thomas H [Instituto de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, CP 62132 Cuernavaca, Morelos (Mexico)], E-mail: tomaz.prosen@fmf.uni-lj.si
2008-02-15
We study in this paper the properties of a two-body random matrix ensemble for distinguishable spins. We require the ensemble to be invariant under the group of local transformations and analyze a parametrization in terms of the group parameters and the remaining parameters associated with the 'entangling' part of the interaction. We then specialize to a spin chain with nearest-neighbour interactions and numerically find a new type of quantum-phase transition related to the strength of a random external field, i.e. the time-reversal-breaking one-body interaction term.
The two-body random spin ensemble and a new type of quantum phase transition
Pižorn, Iztok; Prosen, Tomaž; Mossmann, Stefan; Seligman, Thomas H.
2008-02-01
We study in this paper the properties of a two-body random matrix ensemble for distinguishable spins. We require the ensemble to be invariant under the group of local transformations and analyze a parametrization in terms of the group parameters and the remaining parameters associated with the 'entangling' part of the interaction. We then specialize to a spin chain with nearest-neighbour interactions and numerically find a new type of quantum-phase transition related to the strength of a random external field, i.e. the time-reversal-breaking one-body interaction term.
Probing SUSY CP violation in two-body stop decays at the LHC
Deppisch, Frank F.; Kittel, Olaf
2009-09-01
We study CP asymmetries in two-body decays of top squarks into neutralinos and sleptons at the LHC. These asymmetries are used to probe the CP phases possibly present in the stop and neutralino sector of the Minimal Supersymmetric Standard Model. Taking into account bounds from experimental electric dipole moment searches, we identify areas in the mSUGRA parameter space where CP asymmetries can be sizeable and discuss the feasibility of their observation at the LHC. As a result, potentially detectable CP asymmetries in stop decays at the LHC are found, motivating further detailed experimental studies for probing SUSY CP phases.
Surface Tension Supported Floating of Heavy Objects: Why Elongated Bodies Float Better?
Bormashenko, Edward
2015-01-01
Floating of bodies heavier than the supporting liquid is discussed. Floating of cylindrical, ellipsoidal bodies and rectangular plates possessing lateral dimensions smaller than the capillary length is treated. It is demonstrated that more elongated bodies of a fixed volume are better supported by capillary forces, due to the increase in the perimeter of the triple line. Thus, floating of metallic needles obtains reasonable explanation.
A detailed study of nonperturbative solutions of two-body Dirac equations
Energy Technology Data Exchange (ETDEWEB)
Crater, H.W.; Becker, R.L.; Wong, C.Y.; Van Alstine, P.
1992-12-01
In quark model calculations of the meson spectrums fully covariant two-body Dirac equations dictated by Dirac's relativistic constraint mechanics gave a good fit to the entire meson mass spectrum for light quark mesons as well as heavy quark mesons with constituent world scalar and vector potentials depending on just one or two parameters. In this paper, we investigate the properties of these equations that made them work so well by solving them numerically for quantum electrodynamics (QED) and related field theories. The constraint formalism generates a relativistic quantum mechanics defined by two coupled Dirac equations on a sixteen component wave function which contain Lorentz covariant constituent potentials that are initially undetermined. An exact Pauli reduction leads to a second order relativistic Schroedinger-like equation for a reduced eight component wave function determined by an effective interaction -- the quasipotential. We first determine perturbatively to lowest order the relativistic quasipotential for the Schroedinger-like equation by comparing that form with one derived from the Bethe-Salpeter equation. Insertion of this perturbative information into the minimal interaction structures of the two-body Dirac equations then completely determines their interaction structures. Then we give a procedure for constructing the full sixteen component solution to our coupled first-order Dirac equations from a solution of the second order equation for the reduced wave function. Next, we show that a perturbative treatment of these equations yields the standard spectral results for QED and related interactions.
Neutron-deuteron scattering calculations with W-matrix representation of the two-body input
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Januschke, T.; Kerwath, U.; Sandhas, W.
1987-11-01
Employing the W-matrix representation of the partial-wave T matrix introduced by Bartnik, Haberzettl, and Sandhas, we show for the example of the Malfliet-Tjon potentials I and III that the single-term separable part of the W-matrix representation, when used as input in three-nucleon neutron-deuteron scattering calculations, is fully capable of reproducing the exact results obtained by Kloet and Tjon. This approximate two-body input not only satisfies the two-body off-shell unitarity relation but, moreover, it also contains a parameter which may be used in optimizing the three-body data. We present numerical evidence that there exists a variational (minimum) principle for the determination of the three-body binding energy which allows one to choose this parameter also in the absence of an exact reference calculation. Our results for neutron-deuteron scattering show that it is precisely this choice of the parameter which provides optimal scattering data. We conclude that the W-matrix approach, despite its simplicity, is a remarkably efficient tool for high-quality three-nucleon calculations.
Neutron-deuteron scattering calculations with W-matrix representation of the two-body input
Energy Technology Data Exchange (ETDEWEB)
Bartnik, E.A.; Haberzettl, H.; Januschke, T.; Kerwath, U.; Sandhas, W.
1987-05-01
Employing the W-matrix representation of the partial-wave T matrix introduced by Bartnik, Haberzettl, and Sandhas, we show for the example of the Malfliet-Tjon potentials I and III that the single-term separable part of the W-matrix representation, when used as input in three-nucleon neutron-deuteron scattering calculations, is fully capable of reproducing the exact results obtained by Kloet and Tjon. This approximate two-body input not only satisfies the two-body off-shell unitarity relation but, moreover, it also contains a parameter which may be used in optimizing the three-body data. We present numerical evidence that there exists a variational (minimum) principle for the determination of the three-body binding energy which allows one to choose this parameter also in the absence of an exact reference calculation. Our results for neutron-deuteron scattering show that it is precisely this choice of the parameter which provides optimal scattering data. We conclude that the W-matrix approach, despite its simplicity, is a remarkably efficient tool for high-quality three-nucleon calculations.
Improving the Volume Dependence of Two-Body Binding Energies Calculated with Lattice QCD
Davoudi, Zohreh
2011-01-01
Volume modifications to the binding of two-body systems in large cubic volumes of extent L depend upon the total momentum and exponentially upon the ratio of L to the size of the boosted system. Recent work by Bour et al determined the momentum dependence of the leading volume modifications to nonrelativistic systems with periodic boundary conditions imposed on the single-particle wavefunctions, enabling them to numerically determine the scattering of such bound states using a low-energy effective field theory and Luschers finite-volume method. The calculation of bound nuclear systems directly from QCD using Lattice QCD has begun, and it is important to reduce the systematic uncertainty introduced into such calculations by the finite spatial extent of the gauge-field configurations. We extend the work of Bour et al from nonrelativistic quantum mechanics to quantum field theory by generalizing the work of Luscher and of Gottlieb and Rummukainen to boosted two-body bound states. The volume modifications to bind...
One plus two-body random matrix ensembles with parity: Density of states and parity ratios
Vyas, Manan; Srivastava, P C
2011-01-01
One plus two-body embedded Gaussian orthogonal ensemble of random matrices with parity [EGOE(1+2)-$\\pi$] generated by a chaos producing two-body interaction in the presence of a mean-field, for spinless identical fermion systems, is defined in terms of two mixing parameters and a gap between the positive $(\\pi=+)$ and negative $(\\pi=-)$ parity single particle (sp) states. Numerical calculations are used to demonstrate, using realistic values of the mixing parameters appropriate for some nuclei, that this ensemble generates Gaussian form (with corrections) for fixed parity eigenvalue densities (i.e. state densities). The random matrix model also generates many features in parity ratios of state densities that are similar to those predicted by a method based on the Fermi-gas model for nuclei. We have also obtained a simple formula for the spectral variances defined over fixed-$(m_1,m_2)$ spaces, where $m_1$ is the number of fermions in the $+$ve parity sp states and $m_2$ is the number of fermions in the $-$ve ...
Global solutions to the electrodynamic two-body problem on a straight line
Bauer, G.; Deckert, D.-A.; Dürr, D.; Hinrichs, G.
2017-06-01
The classical electrodynamic two-body problem has been a long standing open problem in mathematics. For motion constrained to the straight line, the interaction is similar to that of the two-body problem of classical gravitation. The additional complication is the presence of unbounded state-dependent delays in the Coulomb forces due to the finiteness of the speed of light. This circumstance renders the notion of local solutions meaningless, and therefore, straightforward ODE techniques cannot be applied. Here, we study the time-symmetric case, i.e., the Fokker-Schwarzschild-Tetrode (FST) equations, comprising both advanced and retarded delays. We extend the technique developed in Deckert and Hinrichs (J Differ Equ 260:6900-6929, 2016), where existence of FST solutions was proven on the half line, to ensure global existence—a result that had been obtained by Bauer (Ein Existenzsatz für die Wheeler-Feynman-Elektrodynamik, Herbert Utz Verlag, München, 1997). Due to the novel technique, the presented proof is shorter and more transparent but also relies on the idea to employ asymptotic data to characterize solutions.
Energy spectra of massive two-body decay products and mass measurement
Agashe, Kaustubh; Hong, Sungwoo; Kim, Doojin
2016-01-01
We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the SM particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial b...
14 CFR 27.751 - Main float buoyancy.
2010-01-01
... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft in...
14 CFR 29.751 - Main float buoyancy.
2010-01-01
... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight of the rotorcraft...
Hydroelasticity of a Floating Plate
DEFF Research Database (Denmark)
Chen, X.; Jensen, Jørgen Juncher; Cui, W.
2003-01-01
The membrane forces are included in the hydroelastic analysis of a floating plate undergoing large vertical deflections in regular monochromatic multidirectional waves. The first-order vertical displacements induced by the linear wave exciting forces are calculated by the mode expansion method...... in the frequency domain. The second-order vertical displacements induced by the membrane forces are calculated by the von Karman plate theory. The results show that the membrane contribution both in terms of the axial stresses and the effect on the bending stresses can be important...
Floating patella associated with lymphoedema
Vun, Shen Hwa; Bayam, Levent; Drampalos, Efstathios; Jesry, Mohammed; Fadel, George
2015-01-01
Ipsilateral injury of more than one component of the knee extensor apparatus is rare. It is mostly associated with previous trauma, surgery, immunosuppression therapy and systemic disease. We present the first documented case of a spontaneous bifocal disruption of the knee extensor apparatus (i.e. floating patella) associated with lymphoedema. This case highlights the importance of considering lymphoedema as another risk factor for rupture of the knee extensor apparatus. It also highlights the importance of assessing all components of the knee extensor apparatus in patients presenting with acute knee injuries. PMID:25802253
Does size and buoyancy affect the long-distance transport of floating debris?
Ryan, Peter G.
2015-08-01
Floating persistent debris, primarily made from plastic, disperses long distances from source areas and accumulates in oceanic gyres. However, biofouling can increase the density of debris items to the point where they sink. Buoyancy is related to item volume, whereas fouling is related to surface area, so small items (which have high surface area to volume ratios) should start to sink sooner than large items. Empirical observations off South Africa support this prediction: moving offshore from coastal source areas there is an increase in the size of floating debris, an increase in the proportion of highly buoyant items (e.g. sealed bottles, floats and foamed plastics), and a decrease in the proportion of thin items such as plastic bags and flexible packaging which have high surface area to volume ratios. Size-specific sedimentation rates may be one reason for the apparent paucity of small plastic items floating in the world’s oceans.
Floating liquid bridge charge dynamics
Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz
2016-01-01
The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.
associated injuries and complications in floating knee management
African Journals Online (AJOL)
Traumatology Surgery, Cotonou Teaching Hospital, Republic of Bénin. Correspondence to: Dr. ... Keywords: Associated injuries, complications, Floating knee, Management .... floating knee: epidemiology, prognostic indicators. & outcome ...
Hydrodynamic interactions between two bodies in waves in 3D time domain
Institute of Scientific and Technical Information of China (English)
WANG Jian-fang; LI Ji-de; CAI Xin-gong; TIAN Ming-qi; Hao Jin-feng
2005-01-01
In this paper, a 3D time domain technique is adopted to calculate the coupled hydrodynamic interaction between two bodies without flare in waves. For verifying the code, two same cylinders are selected to calculate coupled hydrodynamic effects by comparison with the results obtained by 3D frequency method which has been proved to be efficient for solving such problems. In order to improve efficiency of calculation, the effect of history time has been discussed, and an improved method is presented. Moreover, the effect of lateral separation distance is also discussed in detail. The technique developed here may serve as a more rigorous tool to analyze the related transient problems of two ships doing underway replenishment in waves.
One-body and Two-body Fractional Parentage Coefficients for Spinor Bose-Einstein Condensation
Institute of Scientific and Technical Information of China (English)
BAO Cheng-guang
2006-01-01
A very effective tool,namely,the analytical expression of the fractional parentage coefficients (FPC),is introduced in this paper to deal with the total spin states of N-body spinor bosonic systems,where N is supposed to be large and the spin of each boson is one.In particular,the analytical forms of the one-body and two-body FPC for the total spin states with {N} and {N-1,1} permutation symmetries have been derived.These coefficients facilitate greatly the calculation of related matrix elements,and they can be used even in the case of N →∞.Theyappear as a powerful tool for the establishment of an improved theory of spinor Bose-Einstein condensation,where the eigenstates have the total spin S and its Z-component being both conserved.
Charmless Hadronic Two-body Decays of $B_{u}$ and $B_{d}$ Mesons
Chen, Y H; Tseng, B; Yang, K C; Chen, Yaw-Hwang; Cheng, Hai-Yang; Yang, Kwei-Chou
1999-01-01
Two-body charmless nonleptonic decays of B_u and B_d mesons are studied within the framework of generalized factorization in which the effective Wilson coefficients $c^{eff}_i$ are renormalization-scale and -scheme independent while factorization is applied to the tree-level hadronic matrix elements. Contrary to previous studies, our $c_i^{eff}$ do not suffer from gauge and infrared problems. Nonfactorizable effects are parametrized in terms of N_c(LL) and N_c(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Tree and penguin transitions are classified into six different classes. The data of $B^-\\to\\rho^0\\pi^-$ and $B^-\\to\\phi K^-$ clearly indicate that $N_c(LR)\
Entropy theorems in classical mechanics, general relativity, and the gravitational two-body problem
Oltean, Marius; Bonetti, Luca; Spallicci, Alessandro D. A. M.; Sopuerta, Carlos F.
2016-09-01
In classical Hamiltonian theories, entropy may be understood either as a statistical property of canonical systems or as a mechanical property, that is, as a monotonic function of the phase space along trajectories. In classical mechanics, there are theorems which have been proposed for proving the nonexistence of entropy in the latter sense. We explicate, clarify, and extend the proofs of these theorems to some standard matter (scalar and electromagnetic) field theories in curved spacetime, and then we show why these proofs fail in general relativity; due to properties of the gravitational Hamiltonian and phase space measures, the second law of thermodynamics holds. As a concrete application, we focus on the consequences of these results for the gravitational two-body problem, and in particular, we prove the noncompactness of the phase space of perturbed Schwarzschild-Droste spacetimes. We thus identify the lack of recurring orbits in phase space as a distinct sign of dissipation and hence entropy production.
Non-Collision Singularities in the Planar Two-Center-Two-Body Problem
Xue, Jinxin; Dolgopyat, Dmitry
2016-08-01
In this paper, we study a restricted four-body problem called the planar two-center-two-body problem. In the plane, we have two fixed centers Q 1 and Q 2 of masses 1, and two moving bodies Q 3 and Q 4 of masses {μ≪ 1}. They interact via Newtonian potential. Q 3 is captured by Q 2, and Q 4 travels back and forth between two centers. Based on a model of Gerver, we prove that there is a Cantor set of initial conditions that lead to solutions of the Hamiltonian system whose velocities are accelerated to infinity within finite time avoiding all earlier collisions. This problem is a simplified model for the planar four-body problem case of the Painlevé conjecture.
Low-Thrust Orbital Transfers in the Two-Body Problem
Directory of Open Access Journals (Sweden)
A. A. Sukhanov
2012-01-01
Full Text Available Low-thrust transfers between given orbits within the two-body problem are considered; the thrust is assumed power limited. A simple method for obtaining the transfer trajectories based on the linearization of the motion near reference orbits is suggested. Required calculation accuracy can be reached by means of use of a proper number of the reference orbits. The method may be used in the case of a large number of the orbits around the attracting center; no averaging is necessary in this case. The suggested method also is applicable to the cases of partly given final orbit and if there are constraints on the thrust direction. The method gives an optimal solution to the linearized problem which is not optimal for the original nonlinear problem; the difference between the optimal solutions to the original and linearized problems is estimated using a numerical example. Also examples illustrating the method capacities are given.
Regularization of the collision in the electromagnetic two-body problem
Hollander, Efrain Buksman; De Luca, Jayme
2004-12-01
We derive a differential equation that is regular at the collision of two equal-mass bodies with attractive interaction in the relativistic action-at-a-distance electrodynamics. We use the energy constant related to the Poincaré invariance of the theory to define finite variables with finite derivatives at the collision. The collision orbits are calculated numerically using the regular equation adapted in a self-consistent minimization method (a stable numerical method that chooses only nonrunaway solutions). This dynamical system appeared 100 years ago as an example of covariant time-symmetric two-body dynamics and acquired the status of electrodynamics in the 1940s by the works of Dirac, Wheeler, and Feynman. We outline the method with an emphasis on the physics of this complex conservative dynamical system.
One dimensional scattering of a two body interacting system by an infinite wall
Moro, A M; Gomez-Camacho, J
2010-01-01
The one-dimensional scattering of a two body interacting system by an infinite wall is studied in a quantum-mechanical framework. This problem contains some of the dynamical features present in the collision of atomic, molecular and nuclear systems. The scattering problem is solved exactly, for the case of a harmonic interaction between the fragments. The exact result is used to assess the validity of two different approximations to the scattering process. The adiabatic approximation, which considers that the relative co-ordinate is frozen during the scattering process, is found to be inadequate for this problem. The uncorrelated scattering approximation, which neglects the correlation between the fragments, gives results in accordance with the exact calculations when the scattering energy is high compared to the oscillator parameter.
Branching ratios for pbarp annihilation at rest into two-body final states
Abele, A; Amsler, Claude; Baker, C A; Barnett, B M; Batty, C J; Benayoun, M; Bischoff, S; Blüm, P; Braune, K; Bugg, D V; Case, T; Crowe, K M; Degener, T; Doser, Michael; Dünnweber, W; Engelhardt, D; Faessler, M A; Giarritta, P; Haddock, R P; Heinsius, F H; Heinzelmann, M; Herbstrith, A; Herz, M; Hessey, N P; Hidas, P; Hodd, C; Holtzhaussen, C; Jamnik, D; Kalinowsky, H; Kammel, P; Kisiel, J; Klempt, E; Koch, H; Kunze, M; Kurilla, U; Lakata, M; Landua, Rolf; Matthäy, H; McCrady, R; Meier, J; Meyer, C A; Montanet, Lucien; Ouared, R; Peters, K; Pick, B; Ratajczak, M; Regenfus, C; Röthel, W; Spanier, S; Stöck, H; Strassburger, C; Strohbusch, U; Suffert, Martin; Suh, J S; Thoma, U; Tischhäuser, M; Uman, I; Völcker, C; Wallis-Plachner, S; Walther, D; Wiedner, U; Wittmack, K; Zou, B S
2001-01-01
Measurements of two-body branching ratios for pbarp annihilations at rest in liquid and gaseous (12 rho sub S sub T sub P) hydrogen are reported. Channels studied are pbarp-> pi sup 0 pi sup 0 ,pi sup 0 eta, K sup 0 sub S K sup 0 sub L , K sup + K sup -. The branching ratio for the pi sup 0 pi sup 0 channel in liquid H sub 2 is measured to be (6.14+-0.40)x10 sup - sup 4. The results are compared with those from other experiments. The fraction of P-state annihilation for a range of target densities from 0.002 rho sub S sub T sub P to liquid H sub 2 is determined. Values obtained include 0.11+-0.02 in liquid H sub 2 and 0.48+-0.04 in 12 rho sub S sub T sub P H sub 2 gas.
Interesting Characteristics of AMD Barcelona Floating Point Execution
Energy Technology Data Exchange (ETDEWEB)
Bales, Benjamin B [ORNL; Barrett, Richard F [ORNL
2009-01-01
In almost all modern scientific applications, developers achieve the greatest performance gains by tuning algorithms, communication systems, and memory access patterns, while leaving low level instruction optimizations to the compiler. Given the increasingly varied and complicated x86 architectures, the value of these optimizations is unclear, and, due to time and complexity constraints, it is difficult for many programmers to experiment with them. In this report we explore the potential gains of these 'last mile' optimization efforts on an AMD Barcelona processor, providing readers with relevant information so that they can decide whether investment in the presented optimizations is worthwhile.
Real time simulator with Ti floating point digital signal processor
Energy Technology Data Exchange (ETDEWEB)
Razazian, K.; Bobis, J.P.; Dieckman, S.L.; Raptis, A.C.
1994-08-01
This paper describes the design and operation of a Real Time Simulator using Texas Instruments TMS320C30 digital signal processor. This system operates with two banks of memory which provide the input data to digital signal processor chip. This feature enables the TMS320C30 to be utilized in variety of applications for which external connections to acquire input data is not needed. In addition, some practical applications of this Real Time Simulator are discussed.
a Study of the Charged Two-Body Decays of the Neutral D Mesons
Peng, Kuang-Chung (K. C.).
1995-01-01
The charged two-body decays of D^0 mesons produced by 500 GeV/c pi -incident on platium and carbon foil targets at the Fermilab Tagged Particle Laboratory have been analyzed. Three measurements are presented in this thesis: (1) Branching Ratios of Charged Two-body Decays: {Gamma(D^0to K^+K^-)overGamma(D^0to K^-pi^+)}= 0.107+/-0.003 +/-0.003, {Gamma(D^0to pi^+pi^-)over Gamma(D ^0to K^-pi^+)} =0.040 +/-0.002+/-0.002, {Gamma(D^0 to K^+K^-)overGamma(D^0 topi^+pi^-)}=2.65+/-0.14 +/-0.13, and {Gamma(D^0 to K^-pi^-pi^+pi ^+)overGamma(D^0to K^ -pi^+)} =2.19+/-.0.3+/-.0.08; (2) Lifetime Difference: tau_ {KK}=0.414+/-0.012+/-0.014, tau _{Kpi}=0.409+/-0.003+/-0.004, with Deltagamma= {-}0.06 +/-0.15+/-0.15, or the upper limit of Mixing rate as {cal R}_sp {rm mix}{it y}<0.00079 (due to lifetime difference only) at mix 90% confidence level; and (3) CP Asymmetry Parameters: A_sp{CP}{BR}(K^+/- K^mp) = {-}0.018+/-0.054+/-0.012, A_sp{CP}{BR}( pi^+/-pi^mp) = { -}0.053+/-0.093+/-0.029, and A _sp{CP}{BR}(K3pi) - {-}0.018+/-0.023+/-0.002.. All measurements are consistent with most theoretical predictions and world average experimental values.
Street, K. W. Jr.; Kobrick, R. L.; Klaus, D. M.
2011-01-01
A limitation has been identified in the existing test standards used for making controlled, two-body abrasion scratch measurements based solely on the width of the resultant score on the surface of the material. A new, more robust method is proposed for analyzing a surface scratch that takes into account the full three-dimensional profile of the displaced material. To accomplish this, a set of four volume- displacement metrics was systematically defined by normalizing the overall surface profile to denote statistically the area of relevance, termed the Zone of Interaction. From this baseline, depth of the trough and height of the plowed material are factored into the overall deformation assessment. Proof-of-concept data were collected and analyzed to demonstrate the performance of this proposed methodology. This technique takes advantage of advanced imaging capabilities that allow resolution of the scratched surface to be quantified in greater detail than was previously achievable. When reviewing existing data analysis techniques for conducting two-body abrasive scratch tests, it was found that the ASTM International Standard G 171 specified a generic metric based only on visually determined scratch width as a way to compare abraded materials. A limitation to this method was identified in that the scratch width is based on optical surface measurements, manually defined by approximating the boundaries, but does not consider the three-dimensional volume of material that was displaced. With large, potentially irregular deformations occurring on softer materials, it becomes unclear where to systematically determine the scratch width. Specifically, surface scratches on different samples may look the same from a top view, resulting in an identical scratch width measurement, but may vary in actual penetration depth and/or plowing deformation. Therefore, two different scratch profiles would be measured as having identical abrasion properties, although they differ
Floating plant dominance as a stable state
Scheffer, Marten; Szabó, Sándor; Gragnani, Alessandra; van Nes, Egbert H.; Rinaldi, Sergio; Kautsky, Nils; Norberg, Jon; Roijackers, Rudi M. M.; Franken, Rob J. M.
2003-01-01
Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we demonstrate that floating-plant dominance can be a self-stabilizing ecosystem state, which may explain its notorious persistence in many situations. Our results, based on experiments, field data, and models, represent evidence for alternative domains of attraction in ecosystems. An implication of our findings is that nutrient enrichment reduces the resilience of freshwater systems against a shift to floating-plant dominance. On the other hand, our results also suggest that a single drastic harvest of floating plants can induce a permanent shift to an alternative state dominated by rooted, submerged growth forms. PMID:12634429
Helgesson, J; Ekman, J; Helgesson, Johan; Ghetti, Roberta; Jorgen Ekman
2006-01-01
From velocity-gated small-angle correlation functions the emission chronology can be deduced for non-identical particles, if the emission is independent. This is not the case for non-identical particles that originate from two-body decay of fragments. Experimental results may contain contributions from both independent emission and two-body decay, so care is needed in interpreting the velocity-gated correlation functions. It is shown that in some special cases, it is still possible to deduce the emission chronology, even if there is a contribution from two-body decay.
Design and optimization of floating drug delivery system of acyclovir
Directory of Open Access Journals (Sweden)
Kharia A
2010-01-01
Full Text Available The purpose of the present work was to design and optimize floating drug delivery systems of acyclovir using psyllium husk and hydroxypropylmethylcellulose K4M as the polymers and sodium bicarbonate as a gas generating agent. The tablets were prepared by wet granulation method. A 32 full factorial design was used for optimization of drug release profile. The amount of psyllium husk (X1 and hydroxypropylmethylcellulose K4M (X2 were selected as independent variables. The times required for 50% (t 50% and 70% (t 70% drug dissolution were selected as dependent variables. All the designed nine batches of formulations were evaluated for hardness, friability, weight variation, drug content uniformity, swelling index, in vitro buoyancy, and in vitro drug release profile. All formulations had floating lag time below 3 min and constantly floated on dissolution medium for more than 24 h. Validity of the developed polynomial equation was verified by designing two check point formulations (C1 and C2. The closeness of predicted and observed values for t 50% and t 70% indicates validity of derived equations for the dependent variables. These studies indicated that the proper balance between psyllium husk and hydroxypropylmethylcellulose K4M can produce a drug dissolution profile similar to the predicted dissolution profile. The optimized formulations followed Higuchi′s kinetics while the drug release mechanism was found to be anomalous type, controlled by diffusion through the swollen matrix.
Nuclear structure with unitarily transformed two-body plus phenomenological three-body interactions
Energy Technology Data Exchange (ETDEWEB)
Guenther, Anneke
2011-02-02
calculate the {sup 4}He ground-state energy. As they are of direct interest for nuclear astrophysics collective excitation modes, namely giant resonances, are investigated in the framework of the Random Phase Approximation. Including the full three-body interaction would be very time-demanding. Therefore, a density-dependent two-body interaction is used instead. This simple interaction leads to a significant improvement in the description of the isovector dipole and isoscalar quadrupole resonances while the isoscalar monopole resonances remain in good agreement with experimental data compared to the results obtained with pure unitarily transformed two-body interactions. (orig.)
X. Liu (Xiaona); V. Erasmus (Vicky); Q. Wu (Qing); J.H. Richardus (Jan Hendrik)
2014-01-01
textabstractBackground: Floating populations have been repeatedly characterized as "the tipping point" for the HIV epidemic in China. This study aims to systematically summarize and assess the effectiveness of HIV prevention interventions in floating populations in China over the past decade. Method
New CFOA-based floating immittance emulators
Taher Abuelma'atti, Muhammad; Dhar, Sagar Kumar
2016-12-01
This paper presents four new topologies for emulating floating immittance functions. Each circuit uses two or three current-feedback operational-amplifiers (CFOAs) and three passive elements. The proposed topologies can emulate positive/negative lossless and lossy floating inductances, and positive/negative capacitance, resistance and inductance multipliers in addition to floating frequency-dependent positive and negative resistances. The functionality of the proposed circuits is verified using the Advanced Design System software and the AD844 CFOA. The simulation results are in excellent agreement with the theoretical calculations.
Controlled decoherence of floating flux qubits
Institute of Scientific and Technical Information of China (English)
Ji Ying-Hua; Xu Lin
2010-01-01
In Born-Markov approximation, this paper calculates the energy relaxation time T1 and the decoherence time T2 of a floating flux qubit by solving the set of Bloch-Redfield equations. It shows that there are two main factors influencing the floating flux qubits: coupling capacitor in the circuit and the environment resistor. It also discusses how to improvethe quantum coherence time of a qubit. Through shunt connecting/series connecting inductive elements, an inductive environment resistor is obtained and further the reactance component of the environment resistor is improved, which is beneficial to the enhancement of decoherence time of floating flux qubits.
Capillary floating and the billiard ball problem
Gutkin, Eugene
2010-01-01
We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cylinders that float in neutral equilibrium at any orientation with constant contact angles.
A Novel Ideal Floating Inductor Using Translinear Conveyors
Directory of Open Access Journals (Sweden)
Iqbal A. Khan
2003-01-01
Full Text Available An ideal floating inductor circuit using translinear conveyors is introduced. The floating inductor simulator uses two translinear conveyors and a single capacitor in its realization. The circuit provides the current controlled ideal floating inductance without any component matching constraints. Simulation results on the floating inductor simulator verify the theory
14 CFR 23.753 - Main float design.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 23.753 Section 23.753... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main float must meet the requirements of § 23.521. ...
Regularities in Many-body Systems Interacting by a Two-body Random Ensemble
Zhao, Y M; Yoshinaga, N
2003-01-01
The even-even nuclei always have zero ground state angular momenta $I$ and positive parities $\\pi$. This feature was believed to be just a consequence of the attractive short-range interactions between nucleons. However, in the presence of two-body random interactions, the predominance of $I^{\\pi}=0^+$ ground states (0 g.s.) was found to be robust both for bosons and for an even number of fermions. For simple systems, such as $d$ bosons, $sp$ bosons, $sd$ bosons, and a few fermions in single-$j$ shells for small $j$, there are a few approaches to predict and/or explain the distribution of angular momentum $I$ ground state probabilities. An empirical recipe to predict the $I$ g.s. probabilities is available for general cases, but a more fundamental understanding of the robustness of 0 g.s. dominance is still out of reach. Other interesting results are also reviewed concerning other robust phenomena of many-body systems in the presence of random interactions, such as odd-even staggering of binding energies, gen...
Analysis of charmless two-body B decays in factorization-assisted topological-amplitude approach
Energy Technology Data Exchange (ETDEWEB)
Zhou, Si-Hong; Zhang, Qi-An; Lue, Cai-Dian [Institute of High Energy Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physics, Beijing (China); Lyu, Wei-Ran [Renmin University of China, Physics Department, Beijing (China)
2017-02-15
We analyze charmless two-body non-leptonic B decays B → PP, PV under the framework of a factorization-assisted topological-amplitude approach, where P(V) denotes a light pseudoscalar (vector) meson. Compared with the conventional flavor diagram approach, we consider the flavor SU(3) breaking effect assisted by a factorization hypothesis for topological diagram amplitudes of different decay modes, factorizing out the corresponding decay constants and form factors. The non-perturbative parameters of topology diagram magnitudes χ and the strong phase φ are universal; they can be extracted by χ{sup 2} fit from current abundant experimental data of charmless B decays. The number of free parameters and the χ{sup 2} per degree of freedom are both reduced compared with previous analyses. With these best fitted parameters, we predict branching fractions and CP asymmetry parameters of nearly 100 B{sub u,d} and B{sub s} decay modes. The long-standing ππ and πK-CP puzzles are solved simultaneously. (orig.)
Charmless Hadronic Two-body Decays of the $B_s$ Mesons
Chen, Y H; Tseng, B; Chen, Yaw-Hwang; Cheng, Hai-Yang
1999-01-01
Two-body charmless nonleptonic decays of the B_s meson are studied within the framework of generalized factorization in which factorization is applied to the tree level matrix elements while the effective Wilson coefficients are $\\mu$ and renormalization scheme independent, and nonfactorizable effects are parametrized in terms of N_c(LL) and N_c(LR), the effective numbers of colors arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively. Branching ratios of $B_s\\to PP,PV,VV$ decays are calculated as a function of N_c(LR) with two different considerations for N_c(LL). We find that (i) the electroweak penguin contributions account for about 85% (for N_c(LL)=2) of the decay rates of $B_s\\to \\eta\\pi,\\eta'\\pi,\\eta\\rho,\\eta'\\rho,\\phi\\pi,\\phi\\rho$, which receive contributions only from tree and electroweak penguin diagrams; a measurement of them will provide a clean determination of the electroweak penguin coefficient a_9, (ii) electroweak penguin corrections to $B_s\\to\\omega as QCD penguin effects...
Entropy theorems in classical mechanics, general relativity, and the gravitational two-body problem
Oltean, Marius; Spallicci, Alessandro D A M; Sopuerta, Carlos F
2016-01-01
In classical Hamiltonian theories, entropy may be understood either as a statistical property of canonical systems, or as a mechanical property, that is, as a monotonic function of the phase space along trajectories. In classical mechanics, there are theorems which have been proposed for proving the non-existence of entropy in the latter sense. We explicate, clarify and extend the proofs of these theorems to some standard matter (scalar and electromagnetic) field theories in curved spacetime, and then we show why these proofs fail in general relativity; due to properties of the gravitational Hamiltonian and phase space measures, the second law of thermodynamics holds. As a concrete application, we focus on the consequences of these results for the gravitational two-body problem, and in particular, we prove the non-compactness of the phase space of perturbed Schwarzschild-Droste spacetimes. We thus identify the lack of recurring orbits in phase space as a distinct sign of dissipation and hence entropy producti...
Quartet correlations in N = Z nuclei induced by realistic two-body interactions
Energy Technology Data Exchange (ETDEWEB)
Sambataro, M. [Istituto Nazionale di Fisica Nucleare - Sezione di Catania, Catania (Italy); Sandulescu, N. [National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)
2017-03-15
Two variational quartet models previously employed in a treatment of pairing forces are extended to the case of a general two-body interaction. One model approximates the nuclear states as a condensate of identical quartets with angular momentum J = 0 and isospin T = 0 while the other let these quartets to be all different from each other. With these models we investigate the role of alpha-like quartet correlations both in the ground state and in the lowest J = 0, T = 0 excited states of even-even N = Z nuclei in the sd -shell. We show that the ground-state correlations of these nuclei can be described to a good extent in terms of a condensate of alpha-like quartets. This turns out to be especially the case for the nucleus {sup 32}S for which the overlap between this condensate and the shell model wave function is found close to one. In the same nucleus, a similar overlap is found also in the case of the first excited 0{sup +} state. No clear correspondence is observed instead between the second excited states of the quartet models and the shell model eigenstates in all the cases examined. (orig.)
Reactive two-body and three-body collisions of Ba$^+$ in an ultracold Rb gas
Krükow, Artjom; Härter, Arne; Denschlag, Johannes Hecker
2016-01-01
We analyze reactive collisions of a single Ba$^+$ ion in contact with an ultracold gas of Rb atoms at mK$\\times k_{\\mathrm{B}}$ collision energies. Mapping out the Ba$^+$ loss rate dependence on the Rb atom density we can discern two-body reactive collisions from three-body ones and for the first time determine both rate coefficients which are $k_2=3.1(6)(6)\\times 10^{-13}\\textrm{cm}^{3}\\textrm{s}^{-1}$ and $k_3=1.04(4)(45)\\times 10^{-24}\\textrm{cm}^{6}\\textrm{s}^{-1}$, respectively (statistical and systematic errors in parenthesis). Thus, the measured ternary recombination dominates over binary reactions even at moderate atom densities of $n\\approx 10^{12}\\: \\textrm{cm}^{-3}$. The results for Ba$^+$ and Rb are representative for a wide range of cold ion-atom systems and can serve as a guidance for the future development of the field of hybrid atom-ion research.
Shipwreck! The floating inferno: Yarmouth Castle
National Research Council Canada - National Science Library
Armstrong, J; Ramer, H
1998-01-01
The Yarmouth Castle embarked on an overnight trip from Miami to the Bahamas every weekend - until November, 1965, when this midnight cruise to paradise became a floating inferno that left 87 passengers dead...
Physical model tests for floating wind turbines
DEFF Research Database (Denmark)
Bredmose, Henrik; Mikkelsen, Robert Flemming; Borg, Michael
Floating offshore wind turbines are relevant at sites where the depth is too large for the installation of a bottom fixed substructure. While 3200 bottom fixed offshore turbines has been installed in Europe (EWEA 2016), only a handful of floating wind turbines exist worldwide and it is still...... an open question which floater concept is the most economically feasible. The design of the floaters for the floating turbines relies heavily on numerical modelling. While several coupled models exist, data sets for their validation are scarce. Validation, however, is important since the turbine behaviour...... is complex due to the combined actions of aero- and hydrodynamic loads, mooring loads and blade pitch control. The present talk outlines two recent test campaigns with a floating wind turbine in waves and wind. Two floater were tested, a compact TLP floater designed at DTU (Bredmose et al 2015, Pegalajar...
The floating city as an ecosystem
Van Uffelen, C., Rentmeester, S.
2015-01-01
Floating construction: several municipalities in the Netherlands are working with it on a small scale. TU Delft alumnus Rutger de Graaf of the YesDelft company DeltaSync would like to speed things up with his Blue Revolution.
Video-OCS Floating Wind Farm Site
U.S. Geological Survey, Department of the Interior — This data release contains digital video files from the USGS field activity 2014-607-FA, a survey of the Oregon Outer Continental Shelf (OCS) Floating Wind Farm Site...
Genetics Home Reference: Floating-Harbor syndrome
... child may have bones more typical of a child of 2. However, bone age is usually normal by age 6 to 12. Delay in speech development (expressive language delay) may be severe in Floating-Harbor syndrome , ...
Travel Time Estimation Using Floating Car Data
Sevlian, Raffi
2010-01-01
This report explores the use of machine learning techniques to accurately predict travel times in city streets and highways using floating car data (location information of user vehicles on a road network). The aim of this report is twofold, first we present a general architecture of solving this problem, then present and evaluate few techniques on real floating car data gathered over a month on a 5 Km highway in New Delhi.
Capillary floating and the billiard ball problem
Gutkin, Eugene
2010-01-01
We establish a connection between capillary floating in neutral equilibrium and the billiard ball problem. This allows us to reduce the question of floating in neutral equilibrium at any orientation with a prescribed contact angle for infinite homogeneous cylinders to a question about billiard caustics for their orthogonal cross-sections. We solve the billiard problem. As an application, we characterize the possible contact angles and exhibit an infinite family of real analytic non-round cyli...
Analysis of two-body nonleptonic B decays involving light mesons in the standard model
Ali, A.; Greub, C.
1998-03-01
We report a theoretical analysis of the exclusive nonleptonic decays of the B+/- and B0 mesons into two light mesons, some of which have been measured recently by the CLEO Collaboration. Our analysis is carried out in the context of an effective Hamiltonian based on the standard model (SM), using next-to-leading order perturbative QCD calculations. We explicitly take into account the O(αs) penguin-loop diagrams of all four-Fermi operators and the O(αs) tree-level diagram of the chromomagnetic dipole operator, and give a prescription for including their effects in nonleptonic two-body decays. Using a factorization ansatz for the hadronic matrix elements, we show that existing data, in particular, the branching ratios B(B+/--->η'K+/-), B(B+/--->π+/-K0), B(B0(B0¯)-->π-/+K+/-), and B(B+/--->ωh+/-)(h+/-=π+/-,K+/-), can be accounted for in this approach. Thus, theoretical scenarios with a substantially enhanced Wilson coefficient of the chromomagnetic dipole operator (as compared to the SM) and/or those with a substantial color-singlet cc¯ component in the wave function of η' are not required by these data. We predict, among other decay rates, the branching ratios for the decays B0(B0¯)-->π+/-π-/+ and B+/--->π0π+/-, which are close to the present experimental limits. Implications of some of these measurements for the parameters of the CKM matrix are presented.
Nonlocality in many-body quantum systems detected with two-body correlators
Energy Technology Data Exchange (ETDEWEB)
Tura, J., E-mail: jordi.tura@icfo.es [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Augusiak, R.; Sainz, A.B. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Lücke, B.; Klempt, C. [Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover (Germany); Lewenstein, M.; Acín, A. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); ICREA—Institució Catalana de Recerca i Estudis Avançats, Lluis Campanys 3, 08010 Barcelona (Spain)
2015-11-15
Contemporary understanding of correlations in quantum many-body systems and in quantum phase transitions is based to a large extent on the recent intensive studies of entanglement in many-body systems. In contrast, much less is known about the role of quantum nonlocality in these systems, mostly because the available multipartite Bell inequalities involve high-order correlations among many particles, which are hard to access theoretically, and even harder experimentally. Standard, “theorist- and experimentalist-friendly” many-body observables involve correlations among only few (one, two, rarely three...) particles. Typically, there is no multipartite Bell inequality for this scenario based on such low-order correlations. Recently, however, we have succeeded in constructing multipartite Bell inequalities that involve two- and one-body correlations only, and showed how they revealed the nonlocality in many-body systems relevant for nuclear and atomic physics [Tura et al., Science 344 (2014) 1256]. With the present contribution we continue our work on this problem. On the one hand, we present a detailed derivation of the above Bell inequalities, pertaining to permutation symmetry among the involved parties. On the other hand, we present a couple of new results concerning such Bell inequalities. First, we characterize their tightness. We then discuss maximal quantum violations of these inequalities in the general case, and their scaling with the number of parties. Moreover, we provide new classes of two-body Bell inequalities which reveal nonlocality of the Dicke states—ground states of physically relevant and experimentally realizable Hamiltonians. Finally, we shortly discuss various scenarios for nonlocality detection in mesoscopic systems of trapped ions or atoms, and by atoms trapped in the vicinity of designed nanostructures.
Frederico, Tobias; Pace, Emanuele; Salme`, Giovanni
2010-01-01
The electromagnetic properties of the deuteron are investigated within a Light-Front Hamiltonian Dynamics framework, with a current operator that contains both one-body and two-body contributions. In this work, we are considering new two-body contributions, with a dynamical nature generated within a Yukawa model and a structure inspired by a recent analysis of the current operator, that acts on the three-dimensional valence component and fulfills the Ward-Takahashi identity. Preliminary results for the magnetic moment are shown.
Investigating the potential of floating mires as record of palaeoenvironmental changes
Zaccone, C.; Adamo, P.; Giordano, S.; Miano, T. M.
2012-04-01
Peat-forming floating mires could provide an exceptional resource for palaeoenvironmental and environmental monitoring studies, as much of their own history, as well as the history of their surrounds, is recorded in their peat deposits. In his Naturalis historia (AD 77-79), Pliny the Elder described floating islands on Lake Vadimonis (now Posta Fibreno Lake, Italy). Actually, a small floating island (ca. 35 m of diameter and 3 m of submerged thickness) still occurs on this calcareous lake fed by karstic springs at the base of the Apennine Mountains. Here the southernmost Italian populations of Sphagnum palustre occur on the small surface of this floating mire known as "La Rota", i.e., a cup-formed core of Sphagnum peat and rhizomes of Helophytes, erratically floating on the water-body of a submerged doline, annexed to the easternmost edge of the lake, characterised by the extension of a large reed bed. Geological evidence point out the existence in the area of a large lacustrine basin since Late Pleistocene. The progressive filling of the lake caused by changing in climatic conditions and neotectonic events, brought about the formation of peat deposits in the area, following different depositional cycles in a swampy environment. Then, a round-shaped portion of fen, originated around lake margins in waterlogged areas, was somehow isolated from the bank and started to float. Coupling data about concentrations and fluxes of several major and trace elements of different origin (i.e., dust particles, volcanic emissions, cosmogenic dusts and marine aerosols), with climate records (plant micro- and macrofossils, pollens, isotopic ratios), biomolecular records (e.g., lipids), detailed age-depth modelling (i.e., 210Pb, 137Cs, 14C), and humification indexes, the present work is hoped to identify and better understand the reliability of this particular "archive", and thus possible relationships between biogeochemical processes occurring in this floating bog and environmental
[Free-Floating Intraocular Cysts].
Werner, Jens Ulrich; Lang, Gerhard K; Enders, Christian
2017-05-03
Background Free-floating intraocular cysts may be found in the anterior chamber (FZV) and the vitreous (FZG). The first description of a cyst was 150 years ago, and they are considered to be ocular rarities. Materials and Methods The actual knowledge about FZV and FZG is shown on the basis of two exemplary patients. Results and Discussion Patient 1 had a FZV as an incidental finding which had a smooth surface, a slight pigmentation and was translucent. The ultrasound biomicroscopy revealed an echo-free interior space. Without the patient's discomfort and missing treatment indication, a watch-and-wait strategy was chosen. Cysts of the iris can be classified as primary and secondary cysts. Primary cysts of the iris can arise from the stroma as the pigment epithelium wherein it is believed that FZV descend from the pigment epithelium. Secondary cysts and FZV can be generated by tumors, inflammation, epithelial ingrowth, the use of eye-drops or intraocular foreign bodies. Patient 2 showed marked myopic fundus changes and an FZG with a yellowish-greenish surface; the transparency was reduced and the surface was not pigmented. The ultrasound examination also revealed an echo-free interior space. Clinical controls were advised. Congenital and acquired causes are discussed for the formation of FZG. FZG could originate from the pigment epithelium of the iris, but there are conflicting study results. Trauma, inflammation and chorioretinal diseases are considered as a reason for acquired causes of FZG. The genesis, especially of FZG, is still unclear. For the treatment of patients with FZV and FZG, it is important to know the potential causes to be able to make a therapeutic decision. High quality photographic and sonographic documentation is needed in the watch-and-wait strategy. Georg Thieme Verlag KG Stuttgart · New York.
Combustion of liquid fuels floating on water
Directory of Open Access Journals (Sweden)
Garo Jean-Pierre
2007-01-01
Full Text Available The research presented consists of a study of the burning characteristics of a liquid fuel floating on water with emphasis in the phenomena known as boilover. The problem is of technical interest in the petro-chemical industry, particularly from the point of view of pollution and fires resulting from accidental liquid fuel spills in open water. Testing with multicomponent fuels gives information's about events that can occur in a practical situation, while testing with single component fuels permits obtaining fundamental information about the problem. It evidences the major effects caused by the transfer of heat from the fuel to the water underneath. One of these effects is the disruptive burning of the fuel known as boilover, that is caused by the water boiling and splashing, and results in a sharp increase in burning rate and often in the explosive burning of the fuel. It is shown that this event is caused by the onset of water boiling nucleation at the fuel/water interface and that it occurs at an approximate constant temperature that is above the saturation temperature of the water (water is superheated. These measurements conducted in two laboratories, address the major issues of the process by analyzing the effect of the variation of the parameters of the problem (initial fuel-layer thickness, pool diameter, and fuel type, on the burning rate, time to start of boilover, pre-boilover mass ratio, and boilover intensity. Finally, two types of modeling are proposed to describe the heat transfer in fuel and water phases: one simple for practical purposes, the other, more elaborated and transient, taking particularly into consideration the radiation in depth.
Resolution of ambiguous radar measurements using a floating bin correlator
Addison, E. R.; Frost, E. L.
It is pointed out that the Chinese Remainder Theorem (Mooney and Skillman, 1970) can be used to yield unambiguous measurements by comparing outputs allocated to fixed integer number bins using integer arithmetic to modulo to the correct bin number. In general, targets straddling two or more bins or the assignment of an incorrect bin number will yield incorrect parameter values. An ambiguity resolution technique using multiple pulse repetition frequency (PRF) data and a sliding floating point window or 'floating bin' to correlate ambiguous centroided Doppler measurements is proposed. An advantage of the technique is that false targets are much less prevalent than in classical techniques. What is more, the same technique may be employed to resolve ambiguous range wherein centroided range measurements are moduloed with the pulse repetition interval associated with each PRF. Results demonstrate that this method is better than conventional approaches in that the number of false targets produced is significantly lower while simultaneoulsy providing a high probability of correlation. In addition, the correlation can be effected in real time.
On the dynamics of floating structures
Lannes, David
2016-01-01
This paper addresses the floating body problem which consists in studying the interaction of surface water waves with a floating body. We propose a new formulation of the water waves problem that can easily be generalized in order to take into account the presence of a floating body. The resulting equations have a compressible-incompressible structure in which the interior pressure exerted by the fluid on the floating body is a Lagrange multiplier that can be determined through the resolution of a $d$-dimensional elliptic equation, where $d$ is the horizontal dimension. In the case where the object is freely floating, we decompose the hydrodynamic force and torque exerted by the fluid on the solid in order to exhibit an added mass effect; in the one dimensional case $d=1$, the computations can be carried out explicitly. We also show that this approach in which the interior pressure appears as a Lagrange multiplier can be implemented on reduced asymptotic models such as the nonlinear shallow water equations an...
Formulation and optimization of carbamazepine floating tablets
Directory of Open Access Journals (Sweden)
Patel D
2007-01-01
Full Text Available Floating tablets of carbamazepine were developed using melt granulation technique. Bees wax was used as a hydrophobic meltable material. Hydroxypropylmethylcellulose, sodium bicarbonate and ethyl cellulose were used as matrixing agent, gas-generating agent and floating enhancer, respectively. The tablets were evaluated for in vitro buoyancy and dissolution studies. A simplex lattice design was applied to investigate the combined effect of 3 formulation variables i.e. amount of hydroxypropyl methylcellulose ( X 1 , ethyl cellulose ( X 2 and sodium bicarbonate ( X 3 . The floating lag time (F lag , time required for 50% (t 50 and 80% drug dissolution (t 80 were taken as responses. Results of multiple regression analysis indicated that, low level of X 1 and X 2 , and high level of X 3 should be used to manufacture the tablet formulation with desired in vitro floating time and dissolution. Formulations developed using simplex lattice design were fitted to various kinetic models for drug release. Formulation S3 was selected as a promising formulation and was found stable at 40 o and 75% relative humidity for 3 months. Present study demonstrates the use of simplex lattice design in the development of floating tablets with minimum experimentation.
Robinson, S J Q; Robinson, Shadow J.Q.; Zamick, Larry
2002-01-01
Calculations of the spectra of various even-even nuclei in the fp shell ($^{44}$Ti, $^{46}$Ti, $^{48}$Cr, and $^{50}$Cr) are performed with two sets of two-body interaction matrix elements. The first set consists of the matrix elements of the FPD6 interaction. The second set have the same T=1 two-body matrix elements as the FPD6 interaction, but all the T=0 two-body matrix elements are set equal to zero. Despite the drastic differences between the two interactions, the spectra they yield are very similar and indeed it is difficult to say which set gives a better fit to experiment. That the results for the yrast spectra are insensitive to the presence or absence of T=0 two-body matrix elements is surprising because the only bound two nucleon system has T=0, namely the deuteron. Also there is the general folklore that T=0 matrix elements are responsible for nuclear collectivity. Electric quadrupole transition rates are also examined. It is found that the reintroduction of T=0 matrix elements leads to an enhance...
Critical Point Dryer: Tousimis 916B Series C
Federal Laboratory Consortium — Description:CORAL Name: Critical Point DryerThis system utilizes CO 2to dry fragile suspended and floating structures Specifications / Capabilities:Wafer size up to...
Economic Floating Waste Detectionfor Surface Cleaning Robots
Directory of Open Access Journals (Sweden)
Sumroengrit Jakkrit
2017-01-01
Full Text Available Removing waste out of water surface is a routine task and can be operated by using autonomous surface cleaning robots. This paper presents amethodoflaser-based floating waste detection for surface robot guidance when waste positions are unknown beforehand. Basing on concept of refraction and reflection of laser ray, the proposed laser-based technique is proven to be applicable on floating waste detection. The economic waste detector is constructed and mounted on the robot. Five DOF equations of motion are formulated for calculation of waste position incorporating distance measured by the laser and also the robot motion caused by external wind force as well as water surface tension. Experiments were conducted on a pond with calm water and results show that the presented economic waste detection successfully identify and locate position of plastic bottles floating on water surface within the range of 5 meters.
Development of hybrid fluid jet/float polishing process
Beaucamp, Anthony T. H.; Namba, Yoshiharu; Freeman, Richard R.
2013-09-01
On one hand, the "float polishing" process consists of a tin lap having many concentric grooves, cut from a flat by single point diamond turning. This lap is rotated above a hydrostatic bearing spindle of high rigidity, damping and rotational accuracy. The optical surface thus floats above a thin layer of abrasive particles. But whilst surface texture can be smoothed to ~0.1nm rms (as measured by atomic force microscopy), this process can only be used on flat surfaces. On the other hand, the CNC "fluid jet polishing" process consists of pumping a mixture of water and abrasive particles to a converging nozzle, thus generating a polishing spot that can be moved along a tool path with tight track spacing. But whilst tool path feed can be moderated to ultra-precisely correct form error on freeform optical surfaces, surface finish improvement is generally limited to ~1.5nm rms (with fine abrasives). This paper reports on the development of a novel finishing method, that combines the advantages of "fluid jet polishing" (i.e. freeform corrective capability) with "float polishing" (i.e. super-smooth surface finish of 0.1nm rms or less). To come up with this new "hybrid" method, computational fluid dynamic modeling of both processes in COMSOL is being used to characterize abrasion conditions and adapt the process parameters of experimental fluid jet polishing equipment, including: (1) geometrical shape of nozzle, (2) position relative to the surface, (3) control of inlet pressure. This new process is aimed at finishing of next generation X-Ray / Gamma Ray focusing optics.
FLOAT2 WP4: Development of Materials
DEFF Research Database (Denmark)
Esteves, Luis Pedro; Aarup, Bendt
This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC.......This report refers to complementary material testing to support the design and production of UHPC floaters for installation in the Wave Star Machine under FLOAT2 project. The main objective of WP4 is the characterization of mechanical properties of fiber-reinforced UHPC....
Floating Inductance and FDNR Using Positive Polarity Current Conveyors
Pal, K.
2004-01-01
A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.
Floating Inductance and FDNR Using Positive Polarity Current Conveyors
Directory of Open Access Journals (Sweden)
K. Pal
2004-01-01
Full Text Available A generalized circuit based on five positive polarity second-generation current conveyors is introduced. The circuit simulates a floating inductance, capacitor floatation circuit and floating fdnr. All these circuits use grounded capacitors.
Argo Float Data from the APDRC DAPPER Server
National Oceanic and Atmospheric Administration, Department of Commerce — The floats are designed to drift at a fixed pressure (usually 1000 dbar) for 10 days. After this period, the floats move to a profiling pressure (usually between...
Vandendriessche, Sofie; Messiaen, Marlies; O'Flynn, Sarah; Vincx, Magda; Degraer, Steven
2007-02-01
Floating seaweed is considered to be an important habitat for juvenile fishes due to the provision of food, shelter, a visual orientation point and passive transport. The importance of the presence of the highly dynamical seaweed clumps from the North Sea to juvenile neustonic fishes was investigated by analysing both neuston samples (without seaweed) and seaweed samples concerning fish community structure, and length-frequency distributions and feeding habits of five associated fish species. While the neustonic fish community was mainly seasonally structured, the seaweed-associated fish community was more complex: the response of the associated fish species to environmental variables was species specific and probably influenced by species interactions, resulting in a large multivariate distance between the samples dominated by Chelon labrosus and the samples dominated by Cyclopterus lumpus, Trachurus trachurus and Ciliata mustela. The results of the stomach analysis confirmed that C. lumpus is a weedpatch specialist that has a close spatial affinity with the seaweed and feeds intensively on the seaweed-associated invertebrate fauna. Similarly, C. mustela juveniles also fed on the seaweed fauna, but in a more opportunistic way. The shape of the size-frequency distribution suggested enhanced growth when associated with floating seaweed. Chelon labrosus and T. trachurus juveniles were generally large in seaweed samples, but large individuals were also encountered in the neuston. The proportion of associated invertebrate fauna in their diet was of minor importance, compared to the proportions in C. lumpus. Individuals of Syngnathus rostellatus mainly fed on planktonic invertebrates but had a discontinuous size-frequency distribution, suggesting that some of the syngnathids were carried with the seaweed upon detachment and stayed associated. Floating seaweeds can therefore be regarded as ephemeral habitats shared between several fish species (mainly juveniles) that use
Digital Repository Service at National Institute of Oceanography (India)
Youn, Y.-H.; Lee, H.; Chang, Y.-S.; Pankajakshan, T.
Continued observation of ARGO floats or years (about 4 years) makes the conductivity sensor more vulnerable to fouling by marine life and associated drift in salinity measurements. In this paper, we address this issue by making use of floats...
14 CFR 29.757 - Hull and auxiliary float strength.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Hull and auxiliary float strength. 29.757 Section 29.757 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 29.757 Hull and auxiliary float strength. The hull, and auxiliary floats if used, must withstand...
14 CFR 25.753 - Main float design.
2010-01-01
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Main float design. 25.753 Section 25.753 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design...
Dressing the Post-Newtonian two-body problem and Classical Effective Field Theory
Kol, Barak
2009-01-01
We apply a dressed perturbation theory to better organize and economize the computation of high orders of the 2-body effective action of an inspiralling Post-Newtonian gravitating binary. We use the effective field theory approach with the non-relativistic field decomposition (NRG fields). For that purpose we develop quite generally the dressing theory of a non-linear classical field theory coupled to point-like sources. We introduce dressed charges and propagators, but unlike the quantum theory there are no dressed bulk vertices. The dressed quantities are found to obey recursive integral equations which succinctly encode parts of the diagrammatic expansion, and are the classical version of the Schwinger-Dyson equations. Actually, the classical equations are somewhat stronger since they involve only finitely many quantities, unlike the quantum theory. Classical diagrams are shown to factorize exactly when they contain non-linear world-line vertices, and we classify all the possible topologies of irreducible ...
Dunn, M.; Watson, D. K.; Loeser, J. G.
2006-08-01
In this paper, we develop an analytic N-body wave function for identical particles under quantum confinement with a general two-body interaction. A systematic approach to correlation is developed by combining three theoretical methods: dimensional perturbation theory, the FG method of Wilson et. al., and the group theory of the symmetric group. Analytic results are achieved for a completely general interaction potential. Unlike conventional perturbation methods which are applicable only for weakly interacting systems, this analytic approach is applicable to both weakly and strongly interacting systems. This method directly accounts for each two-body interaction, rather than an average interaction so even lowest-order results include beyond-mean-field effects. One major advantage is that N appears as a parameter in the analytical expressions for the energy so results for different N are easy to obtain.
Evidence for the two-body nature of the E1 transition operator in the sdf-interacting boson model
Energy Technology Data Exchange (ETDEWEB)
Barfield, A.F.; Brentano, P. von; Dewald, A.; Zell, K.O.; Zamfir, N.V.; Bucurescu, D.; Ivascu, M.; Scholten, O.
1989-01-01
Two new a absolute transition rates are reported for the nucleus /sup 144/Sm following an (..cap alpha.., ..cap alpha..') Coulomb excitation study. They are B(E3;3/sup -/ -> 0/sup +/)=(38+-3)W.u. and B(E1;3/sup -/ -> 2/sup +/)=2.8+-0.4)x10/sup -3/W.u. This large E1 matrix element, along with the previously known B(E1;1/sup -/ -> 0/sup +/) value support the interpretation of the 1/sup -/ state in this nucleus as 2-phonon 2/sup +/x3/sup -/ excitation. In the frame of the IBM-1+f-boson model we show the need for a two-body term in the E1 transition operator. Estimates for the strenghts of the one and two-body parts of the E1 transition operator are obtained from these experimental data.
40 CFR 65.45 - External floating roof converted into an internal floating roof.
2010-07-01
... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Storage Vessels § 65.45... control storage vessel regulated material emissions by using an external floating roof converted into an...
Design of crossed-mirror array to form floating 3D LED signs
Yamamoto, Hirotsugu; Bando, Hiroki; Kujime, Ryousuke; Suyama, Shiro
2012-03-01
3D representation of digital signage improves its significance and rapid notification of important points. Our goal is to realize floating 3D LED signs. The problem is there is no sufficient device to form floating 3D images from LEDs. LED lamp size is around 1 cm including wiring and substrates. Such large pitch increases display size and sometimes spoils image quality. The purpose of this paper is to develop optical device to meet the three requirements and to demonstrate floating 3D arrays of LEDs. We analytically investigate image formation by a crossed mirror structure with aerial aperture, called CMA (crossed-mirror array). CMA contains dihedral corner reflectors at each aperture. After double reflection, light rays emitted from an LED will converge into the corresponding image point. We have fabricated CMA for 3D array of LEDs. One CMA unit contains 20 x 20 apertures that are located diagonally. Floating image of LEDs was formed in wide range of incident angle. The image size of focused beam agreed to the apparent aperture size. When LEDs were located three-dimensionally (LEDs in three depths), the focused distances were the same as the distance between the real LED and the CMA.
Flow-induced oscillations of a floating moored cylinder
Carlson, Daniel; Modarres-Sadeghi, Yahya
2016-11-01
An experimental study of flow-induced oscillations of a floating model spar buoy was conducted. The model spar consisted of a floating uniform cylinder moored in a water tunnel test section, and free to oscillate about its mooring attachment point near the center of mass. For the bare cylinder, counter-clockwise (CCW) figure-eight trajectories approaching A* =1 in amplitude were observed at the lower part of the spar for a reduced velocity range of U* =4-11, while its upper part experienced clockwise (CW) orbits. It was hypothesized that the portion of the spar undergoing CCW figure eights is the portion within which the flow excites the structure. By adding helical strakes to the portion of the cylinder with CCW figure eights, the response amplitude was significantly reduced, while adding strakes to portions with clockwise orbital motion had a minimal influence on the amplitude of response. This work is partially supported by the NSF-sponsored IGERT: Offshore Wind Energy Engineering, Environmental Science, and Policy (Grant Number 1068864).
Wave Energy, Lever Operated Pivoting Float LOPF Study
DEFF Research Database (Denmark)
Margheritini, Lucia
University in Denmark. The model size was 60cm W x 90cm L x 21cm H. The 60 cm width pointed towards the wave front. The LOPF buoy is characterized by a simple mechanical design with few moving parts and direct electrical output and it is taut moored to the sea bed, so all forces are referenced to the seabed......The fully instrumented Resen Waves Lever Operated Pivoting Float LOPF wave energy buoy model has gone through the first stage of testing in regular waves in scale 1:25 of the North Sea wave conditions, in the 3D deep wave basin at the Hydraulic and Coastal Engineering Laboratory of Aalborg...... for maximum energy output in regular as well as irregular waves. During storms the buoy pivots and streamlines itself to minimize loads on the mooring line. A conservative estimate shows that a full scale system for North Sea conditions has a float size width of 15 m that will, with 60% generator efficiency...
Long, W. S.
1977-01-01
Attempts are made to generate acceptable coordinate systems for two-body configurations. The first method to be tried was to use the body-fitted coordinate system technique to obtain the best system. This technique alone did not produce very good results, so another approach was investigated. This new approach involved using a combination of the body fitted coordinate system procedure and a complex variable transformation method that was used successfully in conformal mapping.
Weinstein, Galina
2015-01-01
Between 1935 and 1936, Einstein was occupied with the Schwarzschild solution and the singularity within it while working in Princeton on the unified field theory and with his assistant Nathan Rosen, on the theory of the Einstein-Rosen bridges. He was also occupied with quantum theory. He believed that quantum theory was an incomplete representation of real things. Together with Rosen and Boris Podolsky he invented the EPR paradox. I demonstrate that the two-body problem in general relativity ...
Floating RC Networks Using Current Conveyors
Zeman, V; J. Cajka; Vrba, K.
1996-01-01
The paper deals with the design of floating one- and/or two-port high-order networks. The current conveyor CCII+ seems to be a suitable active building block for this purpose. Some examples of the above mentioned networks are shown .
Floating RC Networks Using Current Conveyors
Directory of Open Access Journals (Sweden)
V. Zeman
1996-06-01
Full Text Available The paper deals with the design of floating one- and/or two-port high-order networks. The current conveyor CCII+ seems to be a suitable active building block for this purpose. Some examples of the above mentioned networks are shown .
A novel floating offshore wind turbine concept
DEFF Research Database (Denmark)
Vita, Luca; Schmidt Paulsen, Uwe; Friis Pedersen, Troels
2009-01-01
This paper will present a novel concept of a floating offshore wind turbine. The new concept is intended for vertical-axis wind turbine technology. The main purpose is to increase simplicity and to reduce total costs of an installed offshore wind farm. The concept is intended for deep water...
Floating car data for traffic monitoring
DEFF Research Database (Denmark)
Torp, Kristian; Lahrmann, Harry Spaabæk
2005-01-01
This paper describes a complete prototype system that uses Floating Car Data (FCD) for both automatic and manual detection of queues in traffic. The system is developed under EU’s Tempo program. The systems consists of small hardware units placed in mobile traffic report units (we use taxis...
Reis kosmosesse : [Floating-kambrist] / Marika Makarova
Makarova, Marika
2011-01-01
Ameerika psühholoogi John C. Lilly poolt kasutusele võetud Floating-kambrist ehk hõljumisvannist, mis aeglustab ajulaineid ning seeläbi aitab vähendada lihaspinget, stressi, ärevust, peavalusid, vererõhku ning parandada und, selgroo- ja kaelavigastusi, suurendada loovust ja heaolu jne
Immunohistochemistry on freely floating fixed tissue sections.
Bachman, Julia
2013-01-01
Immunohistochemistry on free floating tissue sections is done for many reasons, all of which involve labeling tissue to visualize a certain cell type, protein, or structural component. Visualization is aided by mounting sections on microscope slides for stabilization, and is in most cases necessary for the appropriate use of objectives with a high numerical aperture and high degree of magnification.
Two New Families of Floating FDNR Circuits
Directory of Open Access Journals (Sweden)
Ahmed M. Soliman
2010-01-01
Full Text Available Two new configurations for realizing ideal floating frequency-dependent negative resistor elements (FDNR are introduced. The proposed circuits are symmetrical and are realizable by four CCII or ICCII or a combination of both. Each configuration is realizable by eight different circuits. Simulation results are included to support the theory.
Floating Breakwater Prototype Test Program: Seattle, Washington.
1986-03-01
foam weight increased 250 percent because of the absorption of water. This absorption, combined with underfilling of tires during the original...A 2 the float was done in three lifts of about 1 ft each. Handheld electric vibrators were used to reduce the possibility of voids . After the sides
Near-Shore Floating Wave Energy Converters
DEFF Research Database (Denmark)
Ruol, Piero; Zanuttigh, Barbara; Martinelli, Luca
2011-01-01
Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency...
Reis kosmosesse : [Floating-kambrist] / Marika Makarova
Makarova, Marika
2011-01-01
Ameerika psühholoogi John C. Lilly poolt kasutusele võetud Floating-kambrist ehk hõljumisvannist, mis aeglustab ajulaineid ning seeläbi aitab vähendada lihaspinget, stressi, ärevust, peavalusid, vererõhku ning parandada und, selgroo- ja kaelavigastusi, suurendada loovust ja heaolu jne
Measurement of branching fractions and CP violation for charmless charged two-body B decays at LHCb
Perazzini, Stefano
Charmless charged two-body B decays are sensitive probes of the CKM matrix, that parameterize CP violation in the Standard Model (SM), and have the potential to reveal the presence of New Physics. The framework of CP violation within the SM, the role of the CKM matrix, with its basic formalism, and the current experimental status are presented. The theoretical tools commonly used to deal with hadronic B decays and an overview of the phenomenology of charmless two-body B decays are outlined. LHCb is one of the four main experiments operating at the Large Hadron Collider (LHC), devoted to the measurement of CP violation and rare decays of charm and beauty hadrons. The LHCb detector is described, focusing on the technologies adopted for each sub-detector and summarizing their performances. The status-of-the-art of the LHCb measurements with charmless two-body B decays is then presented. Using the 37/pb of integrated luminosity collected at sqrt(s) = 7 TeV by LHCb during 2010, the direct CP asymmetries ACP(B0 -> ...
Moessbauer spectra of tin in float glass
Energy Technology Data Exchange (ETDEWEB)
Johnson, J.A. [Liverpool John Moores Univ. (United Kingdom). Sch. of the Built Environ.; Johnson, C.E. [Liverpool Univ. (United Kingdom). Dept. of Physics; Williams, K.F.E. [Liverpool Univ. (United Kingdom). Dept. of Physics; Holland, D. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics; Karim, M.M. [Warwick Univ., Coventry (United Kingdom). Dept. of Physics
1995-03-01
Tin is not a major constituent of window glass, but is found at high concentrations in the lower surface of float glass which has been in contact with the molten tin bath. It does not extend far into the surface, but causes the physical and chemical behaviour to differ from that of the upper surface. It is important, therefore, to understand the structural role of tin in silicate glasses and thus its effect on various properties. Moessbauer spectra were taken of three series of glassy materials, namely binary glasses (SnO and SiO{sub 2}) in varying proportions, re-melted float glass containing tin, and float glass from a production plant. The binary glasses contained between 20 and 70% tin which was found to be mainly Sn{sup 2+}, with very small amounts of Sn{sup 4+} in some of them. The spectra showed a small decrease in isomer shift with increase in tine content, which is ascribed to the change in molar volume. The re-melted samples were float glass which was mixed with stannous oxalate in appropriate conditions to try and maintain tin in the 2+ state, and contained up to 15% tin by weight. The spectra show both Sn{sup 4+} and Sn{sup 2+} with rather more in the 4+ oxidation state. The change in the spectra as a function of temperature revealed a large difference in the f-factor (and hence the chemical binding) of the two states. A series of spectra was taken between 17.5 and 900 K for the sample containing 15% tin. From the absorption as a function of temperature the f-factor was determined for both oxidation states, and hence enabled the relative amounts of Sn{sup 4+} and Sn{sup 2+} present in each sample to be estimated. Measurements of the shift as a function of temperature were also made. The float samples were surface material produced by grinding away all but 0.1 mm of the lower surface of industrially produced float glass. The Moessbauer spectra showed them to be predominantly Sn{sup 2+}, as expected from the reducing atmosphere in the float plant.
Development of floating strip micromegas detectors
Energy Technology Data Exchange (ETDEWEB)
Bortfeldt, Jonathan
2014-04-28
Micromegas are high-rate capable, high-resolution micro-pattern gaseous detectors. Square meter sized resistive strip Micromegas are foreseen as replacement of the currently used precision tracking detectors in the Small Wheel, which is part of the forward region of the ATLAS muon spectrometer. The replacement is necessary to ensure tracking and triggering performance of the muon spectrometer after the luminosity increase of the Large Hadron Collider beyond its design value of 10{sup 34} cm{sup -2}s{sup -1} around 2020. In this thesis a novel discharge tolerant floating strip Micromegas detector is presented and described. By individually powering copper anode strips, the effects of a discharge are confined to a small region of the detector. This reduces the impact of discharges on the efficiency by three orders of magnitude, compared to a standard Micromegas. The physics of the detector is studied and discussed in detail. Several detectors are developed: A 6.4 x 6.4 cm{sup 2} floating strip Micromegas with exchangeable SMD capacitors and resistors allows for an optimization of the floating strip principle. The discharge behavior is investigated on this device in depth. The microscopic structure of discharges is quantitatively explained by a detailed detector simulation. A 48 x 50 cm{sup 2} floating strip Micromegas is studied in high energy pion beams. Its homogeneity with respect to pulse height, efficiency and spatial resolution is investigated. The good performance in high-rate background environments is demonstrated in cosmic muon tracking measurements with a 6.4 x 6.4 cm{sup 2} floating strip Micromegas under lateral irradiation with 550 kHz 20 MeV proton beams. A floating strip Micromegas doublet with low material budget is developed for ion tracking without limitations from multiple scattering in imaging applications during medical ion therapy. Highly efficient tracking of 20 MeV protons at particle rates of 550 kHz is possible. The reconstruction of the
Unsteady aerodynamic analysis for offshore floating wind turbines under different wind conditions.
Xu, B F; Wang, T G; Yuan, Y; Cao, J F
2015-02-28
A free-vortex wake (FVW) model is developed in this paper to analyse the unsteady aerodynamic performance of offshore floating wind turbines. A time-marching algorithm of third-order accuracy is applied in the FVW model. Owing to the complex floating platform motions, the blade inflow conditions and the positions of initial points of vortex filaments, which are different from the fixed wind turbine, are modified in the implemented model. A three-dimensional rotational effect model and a dynamic stall model are coupled into the FVW model to improve the aerodynamic performance prediction in the unsteady conditions. The effects of floating platform motions in the simulation model are validated by comparison between calculation and experiment for a small-scale rigid test wind turbine coupled with a floating tension leg platform (TLP). The dynamic inflow effect carried by the FVW method itself is confirmed and the results agree well with the experimental data of a pitching transient on another test turbine. Also, the flapping moment at the blade root in yaw on the same test turbine is calculated and compares well with the experimental data. Then, the aerodynamic performance is simulated in a yawed condition of steady wind and in an unyawed condition of turbulent wind, respectively, for a large-scale wind turbine coupled with the floating TLP motions, demonstrating obvious differences in rotor performance and blade loading from the fixed wind turbine. The non-dimensional magnitudes of loading changes due to the floating platform motions decrease from the blade root to the blade tip.
Input Stage for Low-Voltage, Low-Noise Preamplifiers Based on a Floating-Gate MOS Transistor
DEFF Research Database (Denmark)
Igor, Mucha
1997-01-01
A novel input stage for low-voltage, low-noise preamplifiers for integrated capacitive sensors is presented. The input stage of the preamplifier employs floating-gate MOS transistors which are capable of storing the operation point of the input stage over several years without any severe degradat......A novel input stage for low-voltage, low-noise preamplifiers for integrated capacitive sensors is presented. The input stage of the preamplifier employs floating-gate MOS transistors which are capable of storing the operation point of the input stage over several years without any severe...
Analytic solutions for Wheeler-Feynman interaction: Two bodies in straight-line motion
Stephas, Paul
1992-02-01
Analytic solutions are obtained for two point particles with any total energy that have charges of like sign and whose motions are confined to one dimension. These solutions are obtained by explicitly deriving the conserved quantities associated with Wheeler-Feynman interactions into forms that do not contain integrals but, rather, contain ``partial contributions'' to the momenta and potentials of particle two. The resulting conserved energy, momentum, and Lorentz momentum equations are separated in time to yield one set of equations with variables t1 and t2- (retarded) and another set with variables t1 and t1+ (advanced). These are solved to obtain auxiliary solutions x1r(t1) and x1a(t1), which are then combined for the case m1 = m2 to give the actual world lines x1(t1) and x2(t2). Comparison is made with a previous computer-generated exact solution for the same interaction and energy; good qualitative agreement is found, although some quantitative differences persist.
Corrected Newtonian potentials in the two-body problem with applications
Anisiu, M -C
2016-01-01
The paper deals with an analytical study of various corrected Newtonian potentials. We offer a complete description of the corrected potentials, for the entire range of the parameters involved. These parameters can be fixed for different models in order to obtain a good concordance with known data. Some of the potentials are generated by continued fractions, and another one is derived from the Newtonian potential by adding a logarithmic correction. The zonal potential, which models the motion of a satellite moving in the equatorial plane of the Earth, is also considered. The range of the parameters for which the potentials behave or not similarly to the Newtonian one is pointed out. The shape of the potentials is displayed for all the significant cases, as well as the orbit of Raduga-1M 2 satellite in the field generated by the continued fractional potential U3, and then by the zonal one. For the continued fractional potential U2 we study the basic problem of the existence and linear stability of circular orb...
Corrected Newtonian potentials in the two-body problem with applications
Anisiu, M.-C.; Szücs-Csillik, I.
2016-12-01
The paper deals with an analytical study of various corrected Newtonian potentials. We offer a complete description of the corrected potentials, for the entire range of the parameters involved. These parameters can be fixed for different models in order to obtain a good concordance with known data. Some of the potentials are generated by continued fractions, and another one is derived from the Newtonian potential by adding a logarithmic correction. The zonal potential, which models the motion of a satellite moving in the equatorial plane of the Earth, is also considered. The range of the parameters for which the potentials behave or not similarly to the Newtonian one is pointed out. The shape of the potentials is displayed for all the significant cases, as well as the orbit of Raduga-1M 2 satellite in the field generated by the continued fractional potential U3, and then by the zonal one. For the continued fractional potential U2 we study the basic problem of the existence and linear stability of circular orbits. We prove that such orbits exist and are linearly stable. This qualitative study offers the possibility to choose the adequate potential, either for modeling the motion of planets or satellites, or to explain some phenomena at galactic scale.
Directory of Open Access Journals (Sweden)
Bin Ran
Full Text Available Traffic state estimation from the floating car system is a challenging problem. The low penetration rate and random distribution make available floating car samples usually cover part space and time points of the road networks. To obtain a wide range of traffic state from the floating car system, many methods have been proposed to estimate the traffic state for the uncovered links. However, these methods cannot provide traffic state of the entire road networks. In this paper, the traffic state estimation is transformed to solve a missing data imputation problem, and the tensor completion framework is proposed to estimate missing traffic state. A tensor is constructed to model traffic state in which observed entries are directly derived from floating car system and unobserved traffic states are modeled as missing entries of constructed tensor. The constructed traffic state tensor can represent spatial and temporal correlations of traffic data and encode the multi-way properties of traffic state. The advantage of the proposed approach is that it can fully mine and utilize the multi-dimensional inherent correlations of traffic state. We tested the proposed approach on a well calibrated simulation network. Experimental results demonstrated that the proposed approach yield reliable traffic state estimation from very sparse floating car data, particularly when dealing with the floating car penetration rate is below 1%.
Ran, Bin; Song, Li; Zhang, Jian; Cheng, Yang; Tan, Huachun
2016-01-01
Traffic state estimation from the floating car system is a challenging problem. The low penetration rate and random distribution make available floating car samples usually cover part space and time points of the road networks. To obtain a wide range of traffic state from the floating car system, many methods have been proposed to estimate the traffic state for the uncovered links. However, these methods cannot provide traffic state of the entire road networks. In this paper, the traffic state estimation is transformed to solve a missing data imputation problem, and the tensor completion framework is proposed to estimate missing traffic state. A tensor is constructed to model traffic state in which observed entries are directly derived from floating car system and unobserved traffic states are modeled as missing entries of constructed tensor. The constructed traffic state tensor can represent spatial and temporal correlations of traffic data and encode the multi-way properties of traffic state. The advantage of the proposed approach is that it can fully mine and utilize the multi-dimensional inherent correlations of traffic state. We tested the proposed approach on a well calibrated simulation network. Experimental results demonstrated that the proposed approach yield reliable traffic state estimation from very sparse floating car data, particularly when dealing with the floating car penetration rate is below 1%.
Gao, Bo
2017-04-01
We derive a general relation in two-body scattering theory that more directly relates the change of density of states (DDOS) due to interaction to the shape of the potential. The relation allows us to infer certain global properties of the DDOS from the global properties of the potential. In particular, we show that DDOS is negative at all energies and for all partial waves, for potentials that are more repulsive than +1 /r2 everywhere. This behavior represents a different class of global properties of DDOS from that described by the Levinson's theorem.
Weinstein, Galina
2015-01-01
Between 1935 and 1936, Einstein was occupied with the Schwarzschild solution and the singularity within it while working in Princeton on the unified field theory and with his assistant Nathan Rosen, on the theory of the Einstein-Rosen bridges. He was also occupied with quantum theory. He believed that quantum theory was an incomplete representation of real things. Together with Rosen and Boris Podolsky he invented the EPR paradox. I demonstrate that the two-body problem in general relativity was a heuristic guide in Einstein's and collaborators' 1935 work on the Einstein-Rosen bridge and EPR paradox.
Mirazita, M; Rossi, P; De Sanctis, E; Adams, G; Ambrozewicz, P; Anciant, E; Anghinolfi, M; Asavapibhop, B; Audit, G; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Bertozzi, W; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bouchigny, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Butuceanu, C; Calarco, J R; Carman, D S; Carnahan, B; Chen, S; Cole, P L; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Vita, R; Degtyarenko, P V; Denizli, H; Dennis, L; Deppman, A; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D C; Dragovitsch, P; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Eugenio, P; Fatemi, R; Feuerbach, R J; Ficenec, J; Forest, T A; Funsten, H; Gai, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Gordon, C I O; Griffioen, K; Guidal, M; Guillo, M R; Guo, L; Gyurjyan, V; Hadjidakis, C; Hakobyan, R S; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hu, J; Hyde-Wright, C E; Ilieva, Y; Ito, M M; Jenkins, D; Joo, K; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kühn, J; Kuhn, S E; Lachniet, J; Laget, J M; Lawrence, D; Ji Li; Lima, A C S; Livingston, K; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mehrabyan, S S; Melone, J J; Mestayer, M D; Meyer, C A; Mikhailov, K; Miskimen, R; Mokeev, V; Morand, L; Morrow, S A; Muccifora, V; Müller, J; Mutchler, G S; Napolitano, J; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'Brien, J T; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E A; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O I; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rosner, G; Rowntree, D; Rubin, P D; Sabatie, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabyan, Yu G; Shaw, J; Simionatto, S; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A V; Stepanyan, S; Stokes, B; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Taylor, S; Tedeschi, D J; Thoma, U; Thompson, R; Tkabladze, A; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weller, H; Weygand, D P; Whisnant, C S; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zhang, B; Zhou, Z
2004-01-01
Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CLAS detector and the tagged photon beam at JLab. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10-160 degrees. The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well-described by the non-perturbative Quark Gluon String Model.
Ader, J P
1974-01-01
In the paper, dealing with high-energy quasi-two-body or multiparticle production, the authors focus on what can be learned about exchanged naturality amplitudes from final polarization measurements with polarized or unpolarized beam amd/or target. The separation of t- channel (boson exchange) and u-channel (baryon exchange) exchanges into components of natural and unnatural parity and the measure of naturality interferences are extensively studied in all cases which are now or will be soon available with present experimental techniques. Special attention is paid to the transversity amplitudes which are shown to be always naturality conserving. (19 refs).
Santos, L F; Jacquod, P; Kusnezov, Dimitri; Jacquod, Ph.
2002-01-01
We explore generic ground-state and low-energy statistical properties of many-body bosonic and fermionic one- and two-body random ensembles (TBRE) in the dense limit, and contrast them with Random Matrix Theory (RMT). Weak differences in distribution tails can be attributed to the regularity or chaoticity of the corresponding Hamiltonians rather than the particle statistics. We finally show the universality of the distribution of the angular momentum gap between the lowest energy levels in consecutive J-sectors for the four models considered.
Mirazita, M.; Ronchetti, F.; Rossi, P.; de Sanctis, E.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bertozzi, W.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Chen, S.; Cole, P. L.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; de Vita, R.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deppman, A.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Forest, T. A.; Funsten, H.; Gai, M.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Gordon, C. I.; Griffioen, K.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ilieva, Y.; Ito, M. M.; Jenkins, D.; Joo, K.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuhn, J.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Li, Ji; Lima, A. C.; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McCarthy, J.; McNabb, J. W.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Brien, J. T.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stokes, B.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zhang, B.; Zhou, Z.
2004-07-01
Nearly complete angular distributions of the two-body deuteron photodisintegration differential cross section have been measured using the CEBAF Large Acceptance Spectrometer detector and the tagged photon beam at the Thomas Jefferson National Accelerator Facility. The data cover photon energies between 0.5 and 3.0 GeV and center-of-mass proton scattering angles 10° 160° . The data show a persistent forward-backward angle asymmetry over the explored energy range, and are well described by the nonperturbative quark gluon string model.
Lightning Protection of Floating Roof Tanks
Directory of Open Access Journals (Sweden)
Adekitan,
2013-10-01
Full Text Available Prior to export, processed crude oil is stored in Floating Roof Tanks (FRT to further allow any trapped gas within the crude oil to escape, as this stabilises the crude oil. In the oil and gas industry, FRT’s are vital in the processing of crude oil to the acceptable export specification.In the tropics and other lightning prone regions, lightning induced floating roof tank fire constitutes a major threat to crude oil production. Among others, a single lightning incident could result in the loss of life, product and production time, avoidable incident review time, damaged equipment, wasted repair cost, bad publicity and loss of income.This paper therefore, is aimed at providing an effective solution to the menace of lightning induced tank fire by focussing on the starting process of the lightning induced fire and proposing alternative concepts for breaking the fire triangle before fire ensues
Capillary deposition of advected floating particles
Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico
2016-11-01
The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.
Seismic Response of Submerged Floating Tunnel Tether
Institute of Scientific and Technical Information of China (English)
SU Zhi-bin; SUN Sheng-nan
2013-01-01
A mathematical equation for vibration of submerged floating tunnel tether under the effects of earthquake and parametric excitation is presented.Multi-step Galerkin method is used to simplify this equation and the fourth-order Runge-Kuta integration method is used for numerical analysis.Finally,vibration response of submerged floating tunnel tether subjected to earthquake and parametric excitation is analyzed in a few numerical examples.The results show that the vibration response of tether varies with the seismic wave type; the steady maximum mid-span displacement of tether subjected to seismic wave keeps constant when parametric resonance takes place; the transient maximum mid-span displacement of tether is related to the peak value of input seismic wave acceleration.
Can Oil Float Completely Submerged in Water?
Nath, Saurabh; Chatterjee, Souvick
2013-01-01
Droplet formation in a system of two or more immiscible fluids is a celebrated topic of research in the fluid mechanics community. In this work, we propose an innovative phenomenon where oil when injected drop-wise into a pool of water moves towards the air-water interface where it floats in a fully submerged condition. The configuration, however, is not stable and a slight perturbation to the system causes the droplet to burst and float in partially submerged condition. The droplet contour is analyzed using edge detection. Temporal variation of a characteristic length of the droplet is analyzed using MATLAB image processing. The constraint of small Bond Number established the assumption of lubrication regime in the thin gap. A brief theoretical formulation also showed the temporal variation of the gap thickness
Conceptual Design of Navy Floating Pier.
1982-09-01
which do not have existing flood basins or dry dock facilities. 3.1.3 The Advantages As Navy Piers The floating pier provides a structure well suited to...Bureau of Yards and Docks built 13 reinforced concrete floating repair docks each of 280 ton lift capacity. Bach dock was 390 ft. long, 80 ft. wide and...4 176CK ApoQ &LLKHC-AP6, COLUMNN AND eAr4b V~JricAL- roA~~scN LY T’B 4OPr~C-. I200-+0k CELLO £TNAT STRUCTUARAL EN4GINEERING " NrE FZ IR MJUə
Migration Laws of Floating Population in Mianyang
Institute of Scientific and Technical Information of China (English)
LiuPeng
2005-01-01
Based on the overall anatysis of the floating population among big and medium-sized cities in China, this paper, by means of statistics and questionnaires, makes a systematical study on the migratory features of the floating population in Mianyang, its employment structure, migrating causes and channels, According to the findings, the author finds a fact that with the strategy of Western Development, and with the construction of science and technology city of Mianyang, the migrating in Mianyang conforms to the general patterns of themigration, which has happened in those big and medium-sized cities in China. In addition, the city has a new but unique feature - economic factor, as the driving force of popufation migration, is quite distinct from that of those cities in eastern areas of China.
FLOATING DRUG DELIVERY SYSTEM - CHRONOTHERAPEUTIC APPROACH
Directory of Open Access Journals (Sweden)
Vishal Kalal
2011-04-01
Full Text Available The purpose of writing this review on the floating drug delivery systems (FDDS was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. FDDS is one of the approaches in chronotherapeutic drug delivery. In the past reviews of FDDS the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, their classification and formulation aspects have been covered. This review summarizes the special focus on chronotherapeutics, diseases affected by biological rhythm, its importance, advantages, various approaches in Chronotherapeutic drug delivery and applications of FDDS. These systems are useful for several problems encountered during the development of a pharmaceutical dosage forms.
Voltage-Controlled Floating Resistor Using DDCC
Directory of Open Access Journals (Sweden)
M. Kumngern
2011-04-01
Full Text Available This paper presents a new simple configuration to realize the voltage-controlled floating resistor, which is suitable for integrated circuit implementation. The proposed resistor is composed of three main components: MOS transistor operating in the non-saturation region, DDCC, and MOS voltage divider. The MOS transistor operating in the non-saturation region is used to configure a floating linear resistor. The DDCC and the MOS transistor voltage divider are used for canceling the nonlinear component term of MOS transistor in the non-saturation region to obtain a linear current/voltage relationship. The DDCC is employed to provide a simple summer of the circuit. This circuit offers an ease for realizing the voltage divider circuit and the temperature effect that includes in term of threshold voltage can be compensated. The proposed configuration employs only 16 MOS transistors. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.
Management of "floating elbow" in children
Directory of Open Access Journals (Sweden)
Suresh S
2007-01-01
Full Text Available Background: Supracondylar fractures associated with ipsilateral forearm fractures, aptly termed as "floating elbow" is a rare injury in children after a fall from height. The various authors report their results with conservative treatment of one or both injury to aggressive emergency operative fixation of both components. Materials and Methods: During a period of three years, the author managed four cases of floating elbow in children. All cases were managed by closed reduction and pinning of both components of the injury. Results: All patients recovered full elbow range of motion at three months followup and were rated as excellent as per modified Flynn′s criteria. None of the patients developed cubitus varus deformity, complications related to the pins or delayed union. Conclusions: Early closed reduction and K wire fixation of both components of this injury gives better stability and prevents development of complications like compartment syndrome and elbow deformities.
Floating behavior of hydrophobic glass spheres.
Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng
2009-08-15
When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results.
Floating gate transistors as biosensors (Conference Presentation)
Frisbie, C. Daniel
2016-11-01
Electrolyte gated transistors (EGTs) are a sub-class of thin film transistors that are extremely promising for biological sensing applications. These devices employ a solid electrolyte as the gate insulator; the very large capacitance of the electrolyte results in low voltage operation and high transconductance or gain. This talk will describe the fabrication of floating gate EGTs and their use as ricin sensors. The critical performance metrics for EGTs compared with other types of TFTs will also be reviewed.
Ships as future floating farm systems?
Moustafa, Khaled
2016-09-29
Environmental and agriculture challenges such as severe drought, desertification, sprawling cities and shrinking arable lands in large regions in the world compel us to think about alternative and sustainable farming systems. Ongoing projects to build floating cities in the sea suggest that building specific ships for farming purposes (as farming ships or farming boats) would also be attainable to introduce new farming surfaces and boost food production worldwide to cope with food insecurity issues.
Floating asphalt blocks of the Dead Sea
Energy Technology Data Exchange (ETDEWEB)
Nissenbaum, A. (Weizmann Inst. of Science, Rehovot, Israel); Aizenshtat, Z.; Goldberg, M.
1980-01-01
Large blocks of mineral matter free (less than 0.1%) asphalt are occasionally found floating on the surface of the Dead Sea. Chemical, spectroscopic and isotopic data are given for the asphalt. The source of the asphalt is not accurately known, but presumably it represents mobilization of heavy viscous asphaltic masses at depth below the lake bottom into the floor of the lake. It may be released to the surface by earth tremors.
Stability analysis of the Gyroscopic Power Take-Off wave energy point absorber
DEFF Research Database (Denmark)
Nielsen, Søren R. K.; Zhang, Zili; Kramer, Morten Mejlhede
2015-01-01
The Gyroscopic Power Take-Off (GyroPTO) wave energy point absorber consists of a float rigidly connected to a lever. The operational principle is somewhat similar to that of the so-called gyroscopic hand wrist exercisers, where the rotation of the float is brought forward by the rotational partic...
Turbomachinery systems for floating production applications
Energy Technology Data Exchange (ETDEWEB)
Windt, Jonathan P.; Kurz, Rainer [Solar Turbines Incorporated, San Diego, CA (United States)
2008-07-01
Since 1995 there has been a dramatic increase in oil and gas exploration and production using floating platforms in deeper waters located further offshore. This exploration started with tension leg platforms, progressed through SPARs and Semi-Submersibles, and later evolved into Floating Production Storage and Offloading (FPSO) vessels. Turbomachinery equipment installed on a floating platform or vessel will be expected to operate in the same manner as a land based machine, but in a variety of climate and environmental conditions that now includes motion. To operate successfully, specific design considerations for the turbo-machinery packages are required. It is critical to take into account the type of vessel, the expected list, trim and dynamic motion angles, the dynamic forces applied, the expected deck deflection as a result of those forces, understand the applicable class requirement, and where the equipment will be located on the vessel. This information is then translated into the design conditions to determine the type of mounting method to be used to attach the turbo-machinery package to the deck, the expected accelerations for structural analysis, and oil tank and system designs for fluid management. Furthermore, compressor designs need to allow utmost flexibility to adapt to changing operating conditions. (author)
Mathematical simulation of steep waves at a focus point
Institute of Scientific and Technical Information of China (English)
XU Li; ZHANG Min; WANG Yan-ying
2007-01-01
Mathematical models simulating steep waves at a focus point are presented in this paper. Simulations of extreme waves in a model basin were used to determine the loads on floating structures induced by the waves. Based on a new wave theory, numerical test results show that the simulation procedure is effective and the induced motion of water particles in the front of waves is an important factor influencing impact loads on floating bodies.
Design of single precision float adder (32-bit numbers) according to IEEE 754 standard using VHDL
Barrabés Castillo, Arturo
2012-01-01
Projecte realitzat en el marc d'un programa de mobilitat amb la Slovenská Technická Univerzita v Bratislave, Fakulta Elecktrotechniky a Informatiky [ANGLÈS] Floating Point arithmetic is by far the most used way of approximating real number arithmetic for performing numerical calculations on modern computers. Each computer had a different arithmetic for long time: bases, significant and exponents sizes, formats, etc. Each company implemented its own model and it hindered the portability bet...