An NMR zeugmatographic scanner is modified to produce flow images. A motion sensitizing gradient field is applied to the gyromagnetic nuclei after transverse excitation and prior to emission measurement. The motion sensitized free induction signal which results is processed using an inverse Fourier transformation to produce a number of useful images. Exemplary Claims Claim 1: In a gyromagnetic resonance instrument for producing an image of an extended subject which contains both stationary gyromagnetic material and moving gyromagnetic material, in +L which the instrument +L performs a measurement cycle by applying a transverse excitation signal to a gyromagnetic material and to thereby impart a transverse magnetic moment thereto, and which produces a FID signal responsive to emissions by the transversely magnetized gyromagnetic material, the improvement comprising: means for locating the position of the gyromagnetic material within the extended subject which is producing a FID signal; means for motion sensitizing a FID signal in which a motion sensitizing magnetic field gradient F is applied to the gyromagnetic material for a period of time 2 T after its transverse excitation and prior to the production of the FID signal, and wherein the motion sensitizing magnetic field gradient F has alternating polarity with respect to the gyromagnetic material such that its integral over the time period 2 T is substantially zero; and

An algorithm and data structure are presented for searching a file containing N records, each described by k real valued keys, for the m closest matches or nearest neighbors to a given query record. The computation required to organize the file is proportional to kNlogN. The expected number

Traditional file structures that provide multikey access to records, for example, inverted files, are extensions of file structures originally designed for single-key access. They manifest various deficiencies in particular for multikey access to highly dynamic files. We study the dynamic aspects

) and only a few operations per element scanned. The algorithms are based on statistical observations made on bits of hashed values of records. They are by con- struction totally insensitive to the replicafive structure of elements in the file; they can be used in the context of distributed systems

and Michael Katz deserve special thanks. Above all, this paper – indeed much of the patent-related research of the past two decades – could never have come to pass without the inspiration, support and

We analyzed the UNIX 4.2 BSD file system by recording userlevel activity in trace files and writing programs to analyze the traces. The tracer did not record individual read and write operations, yet still provided tight bounds on what information was accessed and when. The trace analysis shows

in symbolic execution and dynamic test generation. Our approach records an actual run of the program under test on a well-formed input, symbolically evaluates the recorded trace, and gathers constraints on inputs capturing how the program uses these. The collected constraints are then negated one by one

Abstract Very large data sets often have a flat but regular structure and span multiple disks and machines. Examples include telephone call records, network logs, and web document repositories. These large data sets are not amenable to study using traditional database techniques, if only because

numerous seminars, and two anonymous referees for helpful comments. This project would not have been possible without the assistance of several individuals and organizations. MixMasterFlame and the FlameNap network shared P2P data with us, and BigChampagne LLC, the CMJ Network, Nathaniel Leibowitz, and Nevil Brownlee generously provided auxiliary data. We thank Keith Ross and David Weekly for assistance in understanding the KaZaA, OpenNap, and WinMX search protocols and database indices. Sarah Woolverton and Christina Hsiung Chen

to the recording rate, and derive storage granularity and scatten’ng parameters that guarantee continuous access. In order for the file system to support multiple concurrent requests, we develop admission control algorithms for determining whether a new request can be accepted without violating the realtime