An open-air filtration device cleans swimming pools and hot tubs in an efficient, reliable manner. An open-air filter with a suction chamber unit comprises two scrubbing brushes and an impeller powered by a motor drive. Water containing debris is pumped to a level above the swimming pool or hot tub surface. The debris containing water is discharged through a spout into a filter tube. A filter element associated with the filter tube, and open to atmosphere filters the debris containing water by gravitational forces solely. The spout and filter tube are, optionally, attached to a pole that manually propels the suction unit. They may alternatively be attached to a floating platform that floats on the water surface of the pool or hot tub. If filter efficiency decreases, the water level in the filter tube rises, indicating that the filter element must be replaced. A rise in water level is visually observed or detected automatically and communicated using a visible or audible alarm.

1. Field of the Invention
The present invention relates to cleaning devices for removing debris from the bottom and side wall surfaces of swimming pools and hot tubs; and more particularly, to an open-air filtration cleaning device that dislodges the debris from such swimming pool and hot tub surfaces and forces the debris containing water through a filter at or near the pool water surface in a manner so efficient that debris dislodgement and filtering does not deteriorate as a function of pool filtration usage.
2. Description of the Prior Art
Many patents address issues related to pool and hot tub filters and scrubbing devices that loosen dirt from the pool walls and bottom surfaces. They employ either the high-pressure water from pool filter delivery line or an electrical motor to drive the scrubbing brushes, and pass the dirty water through the pool filter which may clog as a function of time thereby decreasing the pool filter operating efficiency.
U.S. Pat. No. 3,886,616 to Hays discloses a hand propelled swimming pool cleaner. It comprises a wheeled frame having a motor driven pump. The pump is adapted to pick up dirt particles from the pool floor and discharges the pumped water with debris through an accordion type filter within the device. An elongated handle is secured to the cleaning device to permit a person at poolside to manually maneuver the cleaner to clean the bottom of the pool. Since the filter in the device is within the motor driven cleaner and is in line with the pressurized water, any clogging of this filter reduces the filtering efficiency. It does not have any scrubbing brush and relies entirely on water flow to dislodge dirt particles from the pools' surfaces.
U.S. Pat. No. 4,338,697 to Broadwater discloses a simplified pool cleaning apparatus. The apparatus comprises a self-contained pool cleaning apparatus having a filter body with dirt and debris collectors positioned on the filter body front and back. During forward movement of the pool cleaning apparatus, the front debris collector is lowered to come into contact with the pool surface by rearward movement of a wheel assembly mounted on the filter body bottom and forward pressure exerted on the filter body by way of handle mounted on the filter body. At the same time, the rearward oriented debris collector is raised away from the pool surface. During backward movement of the pool cleaning apparatus, the wheel assembly moves forward relative to the center of the filter body, resulting in the back debris collector being lowered into operating position engaging the pool surface while the front debris collector is lifted away from the pool surface. During both forward and backward movement, the debris collectors collect dirt and debris carried by the pool water and pass them through a filtering zone. The filtering zone removes the dirt and debris from the pool water and the pool water exits through the top of the filter body. A foraminous partitioned insert and a cloth type filter element are provided within the filter zone for removing the dirt and debris. The disclosed device is manually operated with filters on the front and back sides and is designed to sweep dirt during forward movement and backward movement, respectively. The user can not readily detect filter clogging and there are no scrubbing brushes to loosen dirt adherent to the pools inner surfaces.
U.S. Pat. No. 4,692,956 to Kassis discloses a pool vacuum. This manually operated pool cleaning device is connected to water suction means and has a chamber with partitions wherein the flow of water rotates an agitation member that is fitted with bristles attached to it. The suction action carries debris loosened by the bristles with the pool water. The suction means and filtration means of the debris is not disclosed. Clogging of the filter may reduce suction significantly and will reduce or stop the rotation of the agitation member and the cleaning action of bristles.
U.S. Pat. No. 4,786,334 to Nystrom discloses a method of cleaning the bottom of a pool. The pool cleaner travels along the bottom of the pool and collects material lying on the surface thereof. The pool cleaner is arranged to travel to and fro in straight parallel paths between two opposite walls of the pool using a self-propelled motorized drive mechanism. At the walls the pool cleaner is turned by rotating a half turn so that, after turning, it will have been displaced laterally perpendicular to the initial direction of travel. This motorized device has a drive motor, a pump connected to the motor, and two brushes driven by the motor. The dislodged debris and the pool water mixture are pulled into the pump inlet and are filtered at the pump outlet. The pool cleaner has only a single collection means due to the single travel path of the pool requiring a low capacity pump. When the filter at the pump exit clogs the water suction is reduced, even when the brushes operate effectively. In this automatic self-propelled pool cleaning device the clogging of the filter and subsequent loss of cleaning efficiency are essentially undetectable.
U.S. Pat. No. 5,044,034 to Iannucci discloses a swimming pool vacuum cleaner with a rotary brush. The swimming pool vacuum cleaner has a water-powered turbine and a rotary brush directly and rigidly connected to the turbine so that rotation of the turbine imparts corresponding rotation to the rotary brush. A stationary brush partially surrounds the rotary brush and a foraminate screen is positioned upstream from the brushes to trap residue loosened by the brushes. The swimming pool vacuum cleaner is entirely powered by the external suction of water and means of this suction is not disclosed. The debris loosened by the brush is collected in the foraminate screen positioned upstream from the brushes. As the debris accumulates on the surface of the foraminate screen, clogging occurs. Suction efficiency is reduced and the drive turbine slows down.
U.S. Pat. No. 5,093,950 to Heier discloses a self-propelled vacuum driven swimming pool cleaner. The self-propelled vacuum driven swimming pool cleaner has an outer cover or shroud. The shroud contains a vacuum motor driven by a pool water recirculation system and is connected to a reduction gear train, to rotate a brush assembly, that frictionally engages a surface to be cleaned, and propels the cleaner while scrubbing and then vacuuming loosened dirt and debris from the surface. The pool recirculation system has to filter the debris scrubbed by the self-propelled vacuum driven swimming pool cleaner. When the filter in the pool recirculation system clogs, the efficiency of the vacuum water suction is reduced. This, in turn, reduces the speed of the vacuum water motor that provides self propulsion and scrubbing action.
U.S. Pat. No. 5,293,659 to Rief et al. discloses an automatic swimming pool cleaner comprising a suction head having a housing that is open at its lower side and inclined bristles attached to its' lower edge for support on the cleaning surface. The housing has a rotary sleeve mounted to its' top for the connection of a suction hose in turn to be connected to a water suction pump. Said sleeve opens into a chamber within the housing in which a vibratory element is pivotally mounted, said element having a crescent or air-foil shape. By a flow of water sucked through said chamber, the vibratory element is automatically brought into a vibrating movement which imparts pulsations on the suction head. Thereby, the inclined bristles are bent and straightened repetitively, resulting in a forward thrust moving the suction head over the surface to be cleaned. At least one foot is disposed in the housing which is cyclically displaced vertically by a driving mechanism driven by the movement of the vibratory element and returned by return springs. Said foot cyclically lifts off the suction head at one side, resulting in a rotational movement of the suction head about a vertical axis so as to change the direction of forward movement of the suction head. The disclosed device is operated by water (vacuum) suction which causes a brush to vibrate promoting scrubbing action. The loosened dirt together with the pool water is carried by water suction and has to be cleaned by a filter at the water (vacuum) suction unit. Filter clogging results in reduced water (vacuum) suction and poor movement of vibratory debris dislodging devices.
U.S. Pat. No. 5,351,355 to Chiniara discloses a swimming pool cleaner. The majority of currently available submersible swimming pool cleaners operate in a random manner, following no set path of travel along the bottom of a swimming pool. As a result, a lengthy period of time and a large amount of power consumption are required to clean an entire swimming pool. This problem is resolved by using a submersible swimming pool cleaner, comprising a casing that tapers from one end to the other thereof, a pair of wheels at the wide end of the casing, a single wheel at the narrow end of the casing, a drive system for driving each of the wheels, a cable for connecting the cleaner to a fixed point on one side of the pool, and a cable tensioning device. This cable tensioning device is found within the casing and is utilized for changing the length and tension on the cable whereby the cleaner is caused to follow a predetermined path of travel over the entire inside area of the swimming pool. The swimming pool cleaner is pumped by water (vacuum) suction with an in line filter to remove collected debris. It has two drive wheels on one side and a single drive wheel on the other side driven by a mechanical drive creating a path of motion. There are two rotating scrub brushes on either side of the device. The scrubbing action dislodges the debris and which is then sucked with the pool water and filtered by the in-line filter. When the filter clogs the suction efficiency is significantly decreased. This filter clogging is not easily perceived in this automatic pool cleaning device and therefore the lack of optimal cleaning may not be readily realized.
U.S. Pat. No. 5,435,031 Minami, et al. discloses an automatic pool cleaning apparatus for automatically cleaning submerged surfaces, such as the bottom and sidewalls of a swimming pool. The apparatus includes onboard sensors, and an onboard microprocessor which controls the operation of the apparatus in response to status information supplied from the sensors. The apparatus has an onboard watertight battery and an adjustable inlet nozzle size, and includes left and right track treads which are controllable to enable the apparatus to turn or rotate (clockwise or counterclockwise), or translate in a forward or reverse direction, on a horizontal or vertically inclined submerged surface. A transmission assembly is provided for each track tread, including a cam wheel and a cam follower connected thereto within a sealed control assembly, and a shift link extending through a seal in the control assembly. The apparatus also includes Hall Effect transducers with associated permanent magnets and a microprocessor programmed to execute the selected cleaning program, chosen from a number of available cleaning programs encoded in a punch card. It uses a water suction attachment and a turbine to provide movement. A roller brush powered by the turbine scrubs the swimming pools inner surfaces and the debris containing water is removed through the suction flow stream and filtered. The unit is buoyancy controlled and has the ability to turn in any direction, and thereby matching the pool surface for scrubbing action. Any clogging in the filtering device in the water suction flow stream will reduce the operational efficiency of the turbines and the scrubbing brush.
U.S. Pat. No. 5,569,371 to Perling discloses a system for underwater navigation and control of a mobile swimming pool filter. The underwater navigation and control system for a swimming pool cleaning robot comprises a driver, an impeller, a filter, a processor for controlling the driver, and a signal-producing circuit. The system further includes a signal- detecting circuit mounted on the pool, an interface located on the ground in proximity to the pool, and a detector for receiving and processing data from the detecting circuit and for transmitting signals to the robots processor. Determination of the actual robot location is performed by triangulation in which the stationary triangulation base is defined by at least two spaced-apart signal detectors and the mobile triangle apex is constituted by the signal-producing circuit carried by the robot. The robot is powered by two electrical motors with each motor driving a pair of traction scrubbing brushes. An impeller is used to draw the pool water containing scrubbed debris which is filtered immediately upstream. After filtration, the filtered pool water is returned to the pool. This submerged robot collects all the scrubbed debris in the upstream filter and is subject to clogging. Even though the motors drive the scrubbers and the impeller, the clogged filter prevents efficient filtration of the pool water.
U.S. Pat. No. 5,842,243 to Horvath, et al. discloses a manually propelled pool cleaner. The self-contained manually propelled pool cleaner moves on wheels positioned inboard of the housing, the wheels being supported by axles that extend laterally across the entire width of the housing and are secured at their ends to the side walls and along their length to the lower periphery of the front and rear walls to provide structural integrity and rigidity to the housing. The base plate is provided with pivoting brushes extending diagonally across the direction of travel to move debris towards the intake ports for entrainment in a disposable filter bag. A pivoting off-set connector permits the operator to control the direction of movement by axially twisting the handle while pushing or pulling the cleaner. Electrical power to operate the water pump(s) is supplied from an airtight floating battery case that is tethered to the pool cleaner. This battery powered manually propelled pool cleaner has a motor, a pump, and a scrubbing brush for pumping debris containing pool water through a disposable filter. The clean filtered pool water is released through two ports above the submerged device. When the disposable filter clogs, the user is unaware of the decreased filtering efficiency since the motor continues to pump and drive the scrubbing brushes.
U.S. Pat. No. 5,915,431 to Doussan discloses a pool cleaning apparatus. The pool cleaning apparatus includes a head having a forward portion and a rearward portion, a debris reservoir detachably connected to the rearward portion of the head, a first deflectable blade detachably connected to a lower end of the forward portion of the head being movable downwardly to engage a surface of the pool in response to water flow in the direction of the debris reservoir, and a bracket for connecting a handle to the head. The forward manual movement of the device by the user engages a blade against the pool inner surface scrubbing and loosening debris. The water flow directs the debris containing pool water rearward, where it is filtered in a debris reservoir. There is no water drive or pump suction attached to the device, and therefore there is not a continuous flow of water. When the filter clogs, there is no possibility of debris filtration.
U.S. Pat. No. 5,933,899 to Campbell, et al. discloses a low pressure automatic swimming pool cleaner operating with a pool cleaning system which is not equipped with a booster pump. The apparatus comprises a frame having a forward end and a rearward end with a water inlet mounted on the frame and receiving a supply of water through an inlet. The inlet may comprise a supply mast having a number of openings for supplying water to the various components of the cleaner. The frame is carried on a plurality of transport wheels mounted on the frame. The apparatus further includes a vacuum system including a collection bag positioned on a suction mast having water injection ports positioned such that at least one opening in a water injection port injects water into the collection bag to create suction and draw debris into the bag. A drive system is provided to move the apparatus around the pool. The drive system includes a turbine having a plurality of vanes rotating and mounted in turbine housing. The turbine housing has a first water input and a second water input each oriented to allow a stream of water passing to impact an individual vane at the same angle of incidence as the vane passes through the stream. A drive axle couples to the turbine and at least one set of the plurality of transport wheels. In a further aspect the drive system may include thruster jets positioned on the mast adjacent to the rearward end of the frame. This device is propelled by a turbine driven by a supply of low-pressure water and the collected debris is collected by vacuum suction into a collection bag attached to the swimming pool cleaner. Any blockage of the filter, which decreases the suction and thereby prevents the pool cleaner from sucking the debris in the pool water, is essentially unknown to the pool user.
U.S. Pat. No. 5,961,822 to Polimeni, Jr. discloses a pool cleaner. The pool cleaner floats on the surface of a pool. The cleaner includes a pump and filter, the filter being connected to the discharge side of the pump. The inlet of the pump is connected to a vacuum hose, which is manually moved around inside the pool to suck up debris by directing water from the pool through the pump and filter. Due to the absence of any filter on the suction or inlet side of the pump, the cleaner maintains its efficiency for a longer time. The cleaner may also include a rotary strainer, placed on the discharge side of the pump, for removing large pieces of debris. The strainer includes a slide-able, transparent access cover, which allows visual monitoring of the condition of the strainer, and permits easy access to the interior of the strainer, for removal of debris. The device only removes loose debris from the pool and does not scrub the pool interior surfaces to loosen adhered debris. Since the filter is on the discharge side of the pump it may become clogged and the pump will no longer suck debris efficiently. Furthermore, clogging of this filter is not detected easily by the pool user.
U.S. Pat. No. 6,039,886 to Henkin, et al. discloses a water suction powered automatic swimming pool cleaning system. The automatic swimming pool cleaner is driven by a source of negative pressure, such as an inlet of a pool pump, and is utilized for cleaning the interior surface of a containment wall and the upper water surface of a swimming pool. The automatic swimming pool cleaner includes a unitary body suited for immersion in the swimming pool and a negative pressure source, for producing a water flow in the body, connected by a hose from the pool pump to the chamber. It has a location control subsystem that uses the water flow for producing a vertical force to selectively place the body either (1) proximate to the water surface or (2) proximate to the wall surface below the water surface. The automatic swimming pool cleaner is manually pulled to clean the pool water surface or the pool's inner walls. The cleaner body has a weight/buoyancy characteristic to cause it to naturally rest either (1) proximate to the pool bottom adjacent to the wall surface (i.e., heavier-than-water) or (2) proximate to the water surface (i.e., lighter-than-water). The buoyancy controlled device has no scrubbing brushes and sucks only loose debris, relying strictly on the pool filter to remove the debris. When the pool filter becomes clogged, the device no longer sucks any debris. The clogging of the filter is not observed by the pool user.
U.S. Pat. No. 6,155,657 to Erlich, et al. discloses a drive track for a self-propelled pool cleaner. The submersible self-propelled pool or tank cleaner includes a pair of moving, driven, endless belts or drive tracks mounted on axles, which carry two cleaning brushes. The driven endless belts are provided with moving side-projecting elements that extend from either the moving drive track or the drive wheels, or both, in order to contact the side wall of the pool and other projecting structural elements in the pool. Furthermore, the moving side-projecting elements prevent the stationary structural elements of the pool cleaner from being damaged by scraping the side of the pool and prevent the hard plastic of the cleaner housing from damaging light-weight swimming pool liners. The drive track or belt is provided with raised transverse rib members that terminate into a tip that projects beyond the edge of the belt and extends beyond the projected line of structural elements along the side of the pool cleaner. The hub of the drive wheels around which the belt passes is provided with an extension member that extends outwardly from the hub perpendicular to the longitudinal axis of the cleaner and the direction of travel, a distance that is sufficient to permit the extension member to contact the side and/or bottom of the pool and to prevent the fixed structural elements of the cleaner from contacting the side wall and/or bottom of the pool. It is unclear how the self propelled pool cleaner is driven or what happens to the debris that has been scrubbed. It appears that the scrubbed debris becomes a part of the pool water and has to be eventually filtered by the pool pump and cleaner.
U.S. Pat. No. 6,199,237 to Budden discloses an underwater vacuum. The underwater vacuum includes a housing having an opening which is positioned adjacent the surface to be cleaned. The housing also supports a rotating brush powered by a turbine energized by suction water flow from the pool pump through the underwater vacuum. The housing has a water outlet, which communicates with the suction of the pool's pump at the surface of the water. The inlet to the turbine has a trap which collects large debris that could damage the turbine blades. The vacuum has two rear wheels that are adjustably attached to the interior of the housing, and two front wheels that are adjustably attached to the exterior of the housing. The underwater vacuum can remove sediment from a water storage reservoir without causing turbidity in the water column. A second handheld embodiment is used for cleaning sloping berms, and has rear wheels that are also powered by the turbine. The manual pool vacuum device has a turbine that is powered by suction water flow by a pool pump at the surface of the pool. The turbine is used to power brushes and to drive the rear wheels. Large debris is filtered at the suction inlet of the device but all the fine sediments are carried to the pool vacuum filter. Any clogging of the pool pump filter results in decreased water flow through the underwater vacuum resulting in reduced efficiency in sediment removal. This clogging event is not observed by the manual user.
U.S. Pat. No. 6,473,927 to Sommer discloses a swimming bath cleaning device. The device has a housing with an intake aperture arranged on the base of the housing through which a liquid to be cleaned is conveyed. The liquid is conveyed by means of a pump into an inner chamber partially enclosed by the housing and by a filter separating a contamination-exposed part from a clean part of the inner chamber. The cleaned water is returned to the pool through a motor suction pump, which may or may not be the pool cleaning pump. The swimming bath cleaning device has scrubbing brushes. There is no means to power the brushes or to propel the manually operated device. When the filter clogs the suction of debris becomes inefficient.
U.S. Patent Application 2001/0050093 to Porat, Joseph discloses a motion detection and control for automated pool cleaner. The automated power-driven pool cleaning apparatus is provided with a motion translating member (MTM) that contacts the surface being cleaned, an associated signal transmitter, and a sensor. The sensor is connected to the pool cleaner's programmed electronic control device, or chip, so that when the cleaner is moving, the MTM moves the signal transmitter past the sensor thereby providing an intermittent signal. When the cleaner stops moving, no intermittent signal is received and after a predetermined period of time, the control device causes the cleaner's drive means to move the cleaner in a different direction. This programmed motion translation member controls the movement of a pool cleaning device. There is no disclosure on a specific pool cleaning device.
U.S. Patent Application 2003/0132152 to Illingworth, Lewis discloses a vortex pool cleaner. The improved pool cleaner utilizes toroidal vortex technology to provide efficient fluid flow in a sealed system, creating a low pressure region which attracts debris. The debris free liquid is returned through the annulus. More specific to the separation chamber, a cylindrical vortex is formed such that a circular pattern of flow exiting from the impeller spirals downward along the chamber's outer wall, and then upward along the chamber's inner wall. At the top of the chamber's inner wall is the opening leading fluid out of the chamber and into the annular duct between the outer and inner tubes. The circular flow of the fluid acts as a centrifuge, forcing the higher mass dust particles outward. The spiraling liquid also creates a pressure in the dust collector that is above that in the body of the separation chamber due to kinetic energy of the circulating fluid. This higher pressure pushes the spiraling air inward, maintaining the fluid's circular path. However, the dust particles are not inhibited from traveling straight into the collector. The sealed system prevents dirt from escaping into surrounding fluid and retains kinetic energy of the flowing fluid. The present invention is also quieter, lighter, and simpler than conventional designs. However, this vortex pool cleaner does not have a scrubber to loosen debris from the pool walls. Furthermore, any debris collected stays within the outer chamber of the vortex swimming pool cleaner and collects there with no discharge possibility.
There remains a need in the art for a reliable, long lasting, trouble free cleaning device for pools and hot tubs that utilizes brushes to scrub and remove adhered debris from the walls thereof while collecting and separating debris from the water with minimal clogging of the filtration device, while maintaining substantially constant the scrubbing, suction, and filtration efficiencies of the device as functions of use time.

Open-air filtration cleaning device for pools and hot tubs


In a computer for evaluating signals from nuclear magnetic resonance tomography and a tomograph using such a computer, the neuronal activity measured during a nuclear magnetic resonance tomographic examination follows a protocol, which reproduces the temporal sequence of stimuli. During a correlation analysis, the sensitivity of known means to changes in the signal-response form normally decreases with each activation cycle. According to the invention, better evaluation results can be achieved in the correlation analysis by using a constant number of n data values in a correlation analysis employing a sliding-window technique. As the data measurement progresses, the oldest value is continuously disposed of and the most recent data value utilized in the calculation.

The invention relates to a computer for evaluating signals from nuclear magnetic resonance tomography and a nuclear resonance tomograph equipped with such a computer.
In medical research, it is desirable to obtain information with respect to the brain activity or, in a wider sense, information concerning the blood flow or the deoxyhemoglobin concentration changes in animal and human organs. The neural activation results in an increase of the blood flow in activated brain areas, which causes a decrease in the blood deoxyhemoglobin concentration. Deoxyhemoglobin (DOH) is a paramagnetic compound which accelerates the nuclear spin-dephasing. If the DOH concentration is lowered because of a brain activity which causes a blood flow, the dampening effect on the NMR radiation in the active areas of the brain is reduced, so that NMR signals (nuclear magnetic resonance signals) of the water contained in the brain have a higher intensity. Mainly the protons of the hydrogen in the water become excited. DOH consequently has a dampening effect on the NMR radiation. It is reduced as a result of brain activity and consequently, permits a localization of the brain activity if examinations utilizing NMR methods are performed. This action mechanism is known in the field under the name BOLD effect (Blood Oxygen Level Dependent-effect) and results in susceptibility-sensitive magnetic resonance measurements at a field strength of a static magnetic field of for example 1.5 Tesla in up to about 10% changes of the image brightness in the activated brain regions. The endogenic contrast compound DOH may be replaced by other contrast compounds, which cause a change in the susceptibility. With NMR imaging methods, layers or volumes are selected which, with suitable input of high-frequency radiation pulses and the application of magnetic gradient fields, provide a measuring signal, which is digitized and stored in the measuring computer in a two- or three-dimensional field.
Normally, FFT is used, but the use of other transformations might also be used. From the recorded raw data, the desired image information is reconstructed by way of a two- or three-dimensional Fourier transformation.
A reconstructed slice image consists of pixels, a volume data set consists of voxels. A pixel is a two-dimensional image element, for example a square, of which the image is composed. A voxel is a three-dimensional volume element, for example a block which, because of measuring techniques, has no sharp limit. The dimensions of a pixel are in the range of 1 mm2, those of a voxel are in the range of 1 mm3. The geometries and dimensions are variable.
Although the images of the measured slices are only two-dimensional, the term xe2x80x9cvoxelxe2x80x9d is also used for them By a comparison of the measured signals in each pixel with the time-dependent plot model function, a stimulus-specific neural activation can be detected and localized. A stimulus may be for example a somato-sensoric, an acoustic, a visual or an olefactoric stimulus as well as a mental or motor task. The model function or, respectively, model time series describes the expected signal change of the magnetic resonance signal as a result of neural activation. Those may be derived or example by empirical rules from the paradigm of the respective experiments. It is essential to take into consideration a time delay of the model function with respect to the paradigm (slow reaction of the blood flow to neural activation).
It is already known how brain activation can be represented by images, which were derived from nuclear spin tomographic data. The computation and the display of the activation images are even possible on a real-time basis that is an image can be created from a data set before the next set of data is obtained. The time gap is typically 1 to 3 seconds.
The most widely used method of detecting neural activity is the correlation analysis. It is realized by computation of the cross-correlation coefficients between a reference vector, that is a model time series, and the time sequences of the voxels taken into consideration. The real time capability of a correlation algorithm requires that the time needed for the renewed computation of the correlation coefficients is constant for each new set of magnetic resonance data recorded.
A real time correlation analysis is known from Cox, R. W., Jesmanowicz, A., J. S. Magn. Reson, Med., 33 230, 1955, which supports the suppression of low-frequency noise by means of a detrending procedure. In a detrending procedure, one tries to reduce the effect of non-stimulus induced signal changes into the time sequences measured. This means mathematically that the measurement vector, that is, the vector which includes the measured time sequence of a voxel is split into the sum of two orthogonal vectors. The part, which is described by a linear combination of detrending vectors, is discarded. The detrending vectors, which in a mathematical sense form a basis, include the time series by whose weighted sum the complete low frequency noise part of the measured time series is described (xe2x80x9ccompletexe2x80x9d within the limits of the given detrending vectors). By applying detrending to the measuring and reference vectors entering with the correlation computations, the effect of non-stimulus induced signal changes on the correlation images can be reduced.
With the application of detrending, the correlation coefficient xcfx81 is calculated according to the formula (1).                     ρ        =                                                            x                →                            S                                                                  r                →                            S                                                          "LeftBracketingBar"                                                x                  →                                S                            "RightBracketingBar"                                                  "LeftBracketingBar"                                                r                  →                                S                            "RightBracketingBar"                                                          (        1        )
Wherein:
xcfx81=correlation coefficient
{right arrow over (x)}s=measurement vector after detrending
{right arrow over (r)}s=reference vector after detrending
Furthermore, Cox, R. W. presented in Comput. Biomed. Res. 29, 162, 1996, the program AFNI, which is based on the algorithm of the first-mentioned publication. The known algorithm is based on elements of a matrix which is obtained by Cholesky analysis of another matrix which is composed of the scalar products of the measurement and reference vectors as well as the detrending vectors.
The neural activation measured with a nuclear spin tomographic examination follows the stimulation paradigm, that is the protocol, which represents the timing of the stimuli. Usually an on-off period (that is, a stimulus xe2x80x9conxe2x80x9d phase followed by a stimulus xe2x80x9coffxe2x80x9d phase) is repeated several times.
If a correlation analysis takes all measuring time points into consideration, the sensitivity for changes of the signal-response form decreases with each activation cycle. However, the prior art methods do not provide for a uniform sensitivity for the change of the signal response form.
It is therefore the principal object of the present invention to provide a computer and a nuclear magnetic resonance tomograph, which deliver improved analysis results. It is a particular object to provide for a uniform sensitivity for the changes of the signal response form. Also, a computer and a nuclear magnetic resonance tomograph are to be provided which permit the implementation of such a solution. For this purpose, a new detrending procedure for the reduction of undesired low-frequency components in the measured signals is to be developed, whereby the implementation is made possible.
In a computer for evaluating signals from nuclear magnetic resonance tomography and a tomograph using such a computer, the neuronal activity measured during a nuclear magnetic resonance tomographic examination follows a protocol, which describes the timing of the stimuli. During a correlation analysis, the sensitivity of known means to changes in the signal-response form normally decreases with each activation cycle. According to the invention, better evaluation results can be achieved in the correlation analysis by using a constant number of n data values in a correlation analysis employing a sliding-window technique. As the data measurement progresses, the oldest value is continuously disposed of and replaced by the most recent data value in the calculation.
The computer provides for a uniform sensitivity for the changes of the signal response form by utilizing a combination of the equations (1), (4), and (5) below. In a first step, the vectors {right arrow over (xcex3)} and {right arrow over (xcex4)} are calculated in accordance with equations (2) and (3) which vectors are composed of the detrending coefficients xcex3i and respectively, xcex4i ({right arrow over (xcex3)}=(xcex3o, xcex3i . . . )T , {right arrow over (xcex4)}=(xcex4o, xcex4i . . . )T. The equations are obtained by minimizing two square functions. The detrending matrix S includes si as column vectors.
xe2x80x83(STS){right arrow over (xcex3)}=ST{right arrow over (X)}xe2x80x83xe2x80x83(2)
(STS){right arrow over (xcex4)}=ST{right arrow over (r)}xe2x80x83xe2x80x83(3)
wherein:
S=detrending matrix with {right arrow over (s)}i as column vectors
ST=transposed of S (matrix is mirrored along its diagonal)
{right arrow over (x)}=measurement vector; includes the measured time series of a voxel
{right arrow over (r)}=reference vector; includes the model time series
T=symbol for transposed of a matrix,
{right arrow over (xcex3)}=vector which includes the coefficients of the detrending vectors for the calculations of {right arrow over (x)}s.
{right arrow over (xcex4)}=vector which includes the coefficients of the detrending vectors for the calculation of {right arrow over (r)}s.
These linear equation systems are solved mathematically efficiently for example by the method of conjugate gradients, if the reference vector varies spatially, or, otherwise, in the simplest way, by multiplication of the inverse matrix which can be determined by means of the method of conjugate gradients. Other methods may be used which are however less efficient. It is possible to transform the extended correlation equation until only such terms remain which can be iteratively calculated. In this way, the correlation coefficients themselves can be iteratively calculated.
In a second step, the expressions for {right arrow over (x)}s and {right arrow over (r)}s are substituted in accordance with the formula (4) and (5):                                           x            →                    S                =                              x            →                    -                                    ∑                              i                =                0                                            L                -                1                                                                                γ                i                                                                            s                  →                                i                                                                        (        4        )                                                      r            →                    S                =                              r            →                    -                                    ∑                              i                =                0                                            L                -                1                                                                                δ                i                                                                            s                  →                                i                                                                        (        5        )
wherein:
{right arrow over (x)}=measurement vector; includes the measured time series of a voxel
L=number of detrending vectors
xcex3i=coefficients of the detrending vectors for the calculation of xs
{right arrow over (r)}=reference vector
xcex4i=coefficients of the detrending vectors for the calculation of rs
{right arrow over (x)}s=measurement vector after detrending
{right arrow over (r)}s=reference vector after detrending
{right arrow over (S)}i=detrending vectors
S=detrending matrix with Si being column vectors
By combining the formulae (1), (4), and (5), formula (6) is derived which represents the basis for the calculation of the correlation coefficients in accordance with the invention, such. that a uniform sensitivity of the calculated values for the changes of the signal response form is guaranteed. The expression for the correlation obtained therewith can be formulated in terms of sub-expressions, which can be iteratively calculated.
In order to guarantee now a uniformly high sensitivity for changes of the signal response form, the xe2x80x9csliding-Windowxe2x80x9d technique was developed, wherein the correlation is limited in accordance with the invention to the n last magnetic resonance data sets. The number n of data sets included in the calculation can be freely selected. Preferably, the number n is maintained constant during a measuring procedure but, while maintaining the iterative computability of xcfx81, the window width can be increased or reduced by one in each time step, or, with a correspondingly increased calculation effort, the window width can be changed as desired The correlation computation includes the respective newly added data value while the oldest data value contained in the data window of n elements used for the computation is discarded. A data window always consists of n data sets, which may be especially two- or three-dimensional, wherein n may be for example between 10 and 20. The selection of this window width (=number of data employed) is decided upon by the person performing the experiments and depends, for example, on the desired sensitivity for the changes of the measured neural activation and the time between two measurements.
A data value in the sense of the invention is to be understood to be an individual number such as an integer number value or an floating point value measured at a particular time point. One data value is assigned to one voxel. A data set is a collection of data values, which belong to a measuring time. A data set comprises the data values of all voxels or a partial amount of all voxels. A data set may comprise one or several slices.
In the method used by R. W. Cox, the correlation analysis occurs exclusively in a cumulative manner, that is, all data sets recorded from the beginning of the measurements enter the correlation computation. As a result, in this state of the art method, the deviations of the measuring signals from the model functions have a smaller effect on the correlation coefficient the later they occur. In contrast thereto, the sliding-window technique according to the invention provides for a uniform sensitivity for the changes of the signal response form. During the initial fill-up phase, the sliding-window method corresponds to a cumulative correlation. Thereafter, the phase of the xe2x80x9cstationary equilibriumxe2x80x9d follows (that means the number of data values n remains constant, wherein with progressing measurement, the oldest data value is eliminated while the newest data value is added) which, like in the Cox algorithm, requires for each time step, a constant calculation effort.
The algorithm developed for performing the sliding-window procedure is represented by the general formula (6):                     ρ        =                                                            x                →                                                          r                →                                      -                                          ∑                i                                                                            δ                  i                                                                  x                  →                                                                                s                    →                                    i                                                                                h                1                                                          h                2                                                                        (        6        )
wherein:
{right arrow over (x)}=measurement vector
{right arrow over (r)}=reference vector
i=index variable, which extends over N data sets
xcex4i=coefficients of the detrending vectors for the calculation of {right arrow over (r)}s
{right arrow over (s)}i=detrending vectors
hi and h2 are defined by the formulae (7) and (8):                               h          1                =                                            x              →                        2                    -                      2                                                      ∑                i                                                                            γ                  i                                                                  x                  →                                                                                s                    →                                    i                                                              +                      2                                                      ∑                                  i                   greater than                   j                                                                                γ                  i                                                                  γ                  j                                                                                s                    →                                    i                                                                                s                    →                                    j                                                              +                                    ∑              i                                                                  γ                i                2                                                                            s                  →                                i                2                                                                        (        7        )                                          h          2                =                                            r              →                        2                    -                      2                                                      ∑                i                                                                            δ                  i                                                                  r                  →                                                                                s                    →                                    i                                                              +                      2                                                      ∑                                  i                   greater than                   j                                                                                δ                  i                                                                  δ                  j                                                                                s                    →                                    i                                                                                s                    →                                    j                                                              +                                    ∑              i                                                                  δ                i                2                                                                            s                  →                                i                2                                                                        (        8        )
wherein:
xcex3i, xcex3j=detrending coefficients for the calculation of xs
sj=detrending vectors s=detrending matrix which includes the si as column vectors.
In a specialized formulation, xcfx81 is obtained in accordance with formula (9):                     ρ        =                              a            -                          b                                            c                N                                                                                d                -                                                      b                    2                                    N                                                                                e                -                                                      c                    2                                    N                                                                                (        9        )
wherein:
N=number of measuring points in the measuring window or current number of measuring points (particularly during the initial phase of the correlation computations)
In the equations (10) to (14) a, b, c, d and e are defined as follows:                     a        =                              ∑            i                                                        x              i                                                  r              i                                                          (        10        )                                b        =                                            ∑              i                                                  r              i                                =                      N                                      r              _                                                          (        11        )                                c        =                                            ∑              i                                                  r              i                                =                      N                                      x              _                                                          (        12        )                                d        =                              ∑            i                                          r            i            2                                              (        13        )                                e        =                              ∑            i                                          x            i            2                                              (        14        )
wherein:
{right arrow over (x)}=average value of N measured values
{right arrow over (r)}=average value of N components of the reference vector
ri components of the reference vector
xi components of the measurement vector
The data sets entering the correlation computation for the equations (6) and (9) as well as (1) can be weighted depending on their index number.
The computation time for a correlation image in accordance with the algorithm according to the invention following formula (6) does not depend on the window width, that is the number n (N may indicate any desired number of data values or data sets; if the sliding-window method is used, for the stationary case N=n).
If there is a (time-dependent) shift between measurement and detrending vector, the scalar product between the vectors can no longer be calculated iteratively. As a result, the detrending vectors can no longer be constant but must be moved as sliding-windows over predetermined number series.
For the detrending vectors, the following selection can be made:
It is assumed that the detrending vectors are the vectors with the elements ti, wherein i numbers the detrending vectors and t runs from the smallest to the largest index number of all magnetic resonance data sets taken into consideration for the correlation. These detrending vectors are called polynomial. The series ti are increasing monotonically. This resultsxe2x80x94disregarding small fluctuationsxe2x80x94in a general decrease of the detrending coefficient during the measurement procedure, since they have to compensate for the increase of the series. A direct visualization of the detrending coefficient would therefore be meaningless. Independent of the experiments performed, similar decreases of the detrending coefficient during the measurement would then occur. These coefficients would provide information concerning the time-dependent changes of the low frequency noise components, which would be difficult to interpret.
In the present case, the coefficients can be easily transformed, in accordance with formula (15) into the values xcex3k which one would obtain with a set of constant detrending vectors:                                                         γ              ~                        k                    =                                    ∑                              i                ≥                k                                            L                -                1                                                                                γ                  i                                                                  (                                                                                i                                                                                k                                                                              )                                                                          t                0                                  i                  -                  k                                                                    ,                            (        15        )
wherein:
xcex3k=corrected xcex3-coefficients
L=number of detrending vectors
i=index variable
k=index variable
to=origin of the sliding-window relative to the beginning of the measurement
xcex3i=uncorrected xcex3 coefficient
the index to is the index of the oldest data set in the window (buffer).
The matrix multiplication is utilized for the vector with the detrending coefficients in each voxel for each time step. The computation efforts for the correction of the detrending coefficients are typically smaller than those for the actual correlation. The subsequent linear transformation of the detrending coefficients, which were determined by the systems of linear equation systems, are required for obtaining from the coefficients information in addition to the correlation coefficients. The additional information comprises particulars concerning the strength of the individual low frequency noise components.
For the instance of non-polynomial detrending vectors, appropriate formulae can be derived. By Taylor expansion of the functions on which the non-polynomial detrending vectors are based, the more general case can be reduced to the case of polynomial detrending vectors.
The correlation results depend decidedly on the selection of the reference vector. Starting with a reference vector, which provides a correlation value at least for some image points (pixels), which correlation value is above a certain threshold (for example 0.5), an iterative improvement can be performed. To this end, a vector is generated by component-wise averaging of the time sequences, whose correlation values are above the threshold, and this vector is used as reference vector for a new correlation computation. The mathematical formulation of this procedure is given in formula (16):                               T          i                =                                            Σ                                                ∀                                      pixels                                                              (                                              k                        ,                        l                                            )                                                                      ⩓                                                      p                                                              (                                              k                        ,                        l                                            )                                                         greater than                   t                                                                                x                              i                ,                k                ,                l                                                                        Σ                                                ∀                                      pixels                                                              (                                              k                        ,                        l                                            )                                                                      ⩓                                                      p                                                              (                                              k                        ,                        l                                            )                                                         greater than                   t                                                                  1                                              (        16        )
wherein:
k, l=pixel coordinates
xcfx81=correlation coefficient
t=correlation threshold (may be between xe2x88x921 and 1 and must be exceeded by the correlation values for a consideration of the respective measurement vector in the sum). ri=the ith component of the reference vector xi,k,l=the ith component of the time sequence of the pixel with the coordinates k, l.
With the new reference vector, a new correlation computation is performed. This procedure, which comprises the calculation of the new reference vector and the correlation coefficients and which is considered to be an iteration step, can be repeated several times whereby the reference vector is optimized: Again the time series for the generation of the reference vector are averaged whose respective correlation coefficient is above the predetermined threshold value. The optimizing occurs by adaptation of the reference vector to the time series, which have the highest correlation coefficients. The threshold can be changed from iteration step to iteration step for example in order to limit the selection of the time series to be averaged. The procedure can also be applied to partial areas for which there are individual reference vectors.
Evaluation of the method according to the invention:
In the stationary equilibrium, the computation time with a SUN Ultra Sparc (143 MHz) for a correlation image with a matrix size of 64xc3x9764 pixels and a detrending vector with identical entries is 0.13 s. Together, with the time required for the scaling of the original and the correlation image of 256xc3x97256 pixels by means of bi-linear interpolation a rate of 2 fps (frames per second) was obtained. The implementations of the algorithms according to the invention were compared with the correlation module of the AFNI (Analysis of Functional Neuro Images) software package with respect to speed, which according to the program description is based on the algorithm described in the publication of Cox, R. W., Jesmanowicz A., Hyde, J. S., Magn. Reson. Med. 33, 230, 1995. The software package is described in the publication of Cox R. W. Comput. Biomed. Res. 29, 162, 1996. Comparable computing times were determined. (Because of the missing sliding-window capability, the comparisons have however only limited value.) During the speed test of the real-time software developed by the applicants, the correlation is performed only with one reference vector, which is constant during a measurement. This however is no limitation in principle. The computation was performed also with only one detrending vector with constant elements.
In summary, it can be said that the computer equipped with the algorithm according to the invention delivers with comparable computing times better results.
The way the computer operates in accordance with the invention is not limited to real time measurements. It is also possible to employ measurement values, which are stored in data storage devices.
Also data values and data sets from nuclear magnetic resonance spectroscopy measurements can be evaluated by the computer according to the invention. Consequently, also any nuclear magnetic resonance spectrometer should be included in the term nuclear spin tomograph. In accordance with the invention, the computer includes evaluation means, which operate according to the formula (2), (3) and (6) to (16) or the mathematical equivalent expressions thereof. These means could be chips or respectively, integrated circuits, that is, particularly processors or programmable logic components.
With the computer according to the invention and with the nuclear spin tomograph utilizing this computer, it can also be determined if a patient is susceptible to a stroke so that important decisions can be more competently made before surgeries. In addition, therapy plans and surgery planning for stroke patients can be performed and supported.
Furthermore, the blood supply to all organs can be determined.
The essential steps of the operating method of the computer according to the invention and of the nuclear resonance tomograph are here shortly summarized:
First, the number of detrending vectors L and the window width n are determined. Storage for the required auxiliary variables of the equations (2), (3) and (6) or respectively, (9) is allocated. Also, the correct initialization values are determined. For the equation (6) as well as the equation (9), a distinction between the xe2x80x9cfillupxe2x80x9d mode (cumulative correlation at the beginning of the computation) and the stationary phase has to be made.
In the first case, only numbers are added to the auxiliary variables (in equation (9), a, b, c, d, and e are the auxiliary variables; in equation (6) an auxiliary variable is assigned to each sum), in the last case, additionally values are subtracted.
If the equation (6) is used, the detrending coefficient must be calculated using the formulae (2) and (3). The matrices of the systems of equation (dimensions Lxc3x97L) and the vectors on the right side of the equal sign can be iteratively actualized with each time step. After actualization of the auxiliary variables of the equation (6), the correlation coefficient can be calculated according to the formula (6). The solution of the formula (9) follows correspondingly. In this case, equations (2) and (3) are not used. In the examples, the correlation computation for a single correlation value is demonstrated wherein three polynomial detrending vectors were selected (t{circumflex over ( )}0, t{circumflex over ( )}1, t{circumflex over ( )}2). In the first example, the reference and the measurement vectors of an actual experiment were used; in the second example, they were generated by chance.

Computer for evaluating signals from nuclear magnetic resonance tomography and a nuclear resonance tomograph equipped with said computer


The generator of the invention includes an initialization circuit (CI) delivering four initialization words (QI, RI, SI, TI), one calculation circuit (CC) composed of four sub-units (SQ, SR, SS, ST) corresponding to four generating polynomials of orders 5, 5, 7 and 7, and finally one output logic circuit (CS) delivering a pseudo-random byte sequence.. Application for systems with access control, especially television systems.

The French patent application FR-A-2 448 824 describes a videography system in which the data is locked byte by byte with the aid of scrambling bytes delivered by a pseudo-random generator. This generator is made up of a set of trigger circuits and exclusive-OR gates. The performance of this type of generator is relatively mediocre when implanted in software. By way of indication, it needs about 6 seconds to descramble a televised page containing 1 kilo-byte.
The European patent EP-A-0 083 998 (corresponding to the American patent U.S. Pat. No. 4,543,559) describes a more high-performing and particularly faster pseudorandom generator without being more complex. Furthermore, the period of the pseudo-random sequence generated is increased up to about 2.3.10.sup.30 bytes. To this effect, the generator includes one initialization input and three sub-units each constituted by logic exclusive-OR gates, various registers and one adder. These sub-units define three recurrent sequences. A logic output circuit makes it possible to combine various bits appearing in these three sub-units. This logic circuit delivers 5 bits constituting the least significant 5 bits of one scrambling byte, the bits 6 and 7 being preset at 0 and the 8th being one parity bit calculated by an adder.
Although satisfactory in certain respects, this generator does have the drawback of only delivering 5 pseudo-random bits.

France Telecom Etablissement Autonome de Droit Public (Centre National d'Etudes des Telecommunications)

Etablissement Publics Telediffusion de France


A circuit configuration includes at least one nonvolatile, electrically erasable and writable memory area. Each memory area is assigned a nonvolatile, electrically writable and erasable flag memory, which is connected through an address line, a programming line and an authentication line to the assigned memory area, a programming voltage source and a data verification circuit. In the event of an alteration in the content of a memory area, the state of the associated flag memory is changed and, after verification of the programmed memory area content, the flag memory is returned to its basic state.

1. Field of the Invention
The invention relates to a circuit configuration having at least one nonvolatile, electrically erasable and writable memory area. An addressing circuit is assigned to the memory area and connected thereto through address lines. A programming voltage source is connected to the memory area through a programming line. The invention additionally relates to a method for authenticating the content of a nonvolatile, electrically writable and erasable memory area.
Such a circuit configuration and such a method are disclosed in German Published, Non-Prosecuted Patent Application DE 44 39 266 A1, corresponding to U.S. Pat. No. 5,889,266. In that document, the content of the memory area which is contained in a portable data carrier, for example a smart card, represents a cash value which can be increased or decreased by changing the memory area content. There is a risk of fraud and manipulation, particularly in the case of data representing cash values, but also in the case of other data.
Therefore, most applications of such data carriers demand not only the genuineness of the card and terminal but also the authenticity of the stored data. Data carriers which contain an access-protected memory area therefore require a release logic which allows or does not allow access to the protected area. In a simple case, such logic can carry out the verification of a code, as is described in International Publication No. WO 95/16238, or, in complex implementations, as in German Published, Non-Prosecuted Patent Application DE 44 39 266 A1, corresponding to U.S. Pat. No. 5,889,266, such logic can demand, prior to a release, the authentication of the terminal altering the memory content. Access must then be granted at least until a specific volume of data has been able to be transferred to the card.
A possibility of manipulating the card data arises when the data transfer is corrupted after the release of the protected area or the card is transferred to a fraudulent terminal with the voltage supply being maintained, for example through the use of a battery. Although that manipulation may be recognized and recorded by the releasing terminal, the corruption of the data by the fraudulent terminal can nevertheless not be prevented. If, in an application, there is no networking of all terminals, which can hardly be presupposed, there is the possibility of obtaining an advantage with the falsified data at a different terminal.
One solution for preventing data manipulation after the release of the protected area resides in storing the data in an encrypted manner with a signature. However, that cannot afford protection against a replay of a valuable state.
It is accordingly an object of the invention to provide a circuit configuration and a method for authenticating the content of a memory area, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and which allow reliable authentication of stored data and at the same time require little in the way of circuitry and time.
With the foregoing and other objects in view there is provided, in accordance with the invention, a circuit configuration, comprising at least one nonvolatile, electrically erasable and writable memory area. An addressing circuit is associated with the at least one memory area. Address lines are connected between the at least one memory area and the addressing circuit. A programming line is connected between a programming voltage source and the at least one memory area and is also connected between the at least one flag memory and the programming voltage source. At least one nonvolatile, electrically writable and erasable flag memory is respectively assigned to the at least one memory area. An address line is connected between the at least one flag memory and the at least one memory area. A data line is connected between the authentication circuit and the at least one memory area. An authentication line is connected between the at least one flag memory and the data authentication circuit. Upon an alteration in a content of a memory area, a state of the assigned flag memory is changed and, after authentication of a programmed memory area content, the assigned flag memory is returned to a basic state.
With the objects of the invention in view, there is also provided a method for authenticating a content of a nonvolatile, electrically writable and erasable memory area, which comprises simultaneously changing a state of a nonvolatile, electrically writable and erasable flag memory associated with to the memory area, when the memory area is changed. The flag memory returns to a basic state after authentication of the content of the memory area.
Accordingly, the circuit configuration of the invention uses permanent flag memory cells or cell complexes which indicate whether or not memory areas assigned thereto contain authenticated data. If the release operation is followed by access to a memory area which alters the data thereof, then this is recorded in the associated flag by the flag being set. Once the alteration of the data of a memory area is concluded, which can be effected both by writing and by erasure, authentication of this memory area by the terminal must be effected, which resets the assigned flag as a result.
In accordance with a concomitant mode of the invention, the flag cells are incorporated in the authentication of the corresponding memory areas. It is also possible to interrogate the state of a flag memory at a different point in time. However, for reasons of manipulation security, this should be effected in encrypted form, although this results in a greater complexity. Thus, this flag which can only be changed internally in the card can be used to check whether or not the data of an area in question has been altered by an authorized terminal.
The above-mentioned flag cells can be realized by little additional outlay on hardware. The frequency of the data authentications can be handled more flexibly, depending on the memory area size, than in the case of the above-mentioned signature method, at least as far as circuit configurations without controllers are concerned. By virtue of the smaller number of authentications, the complexity for an authentication can be made higher and the method can thus be made more secure. Furthermore, the increased security level can optionally be used by the flag cells without thereby opening up a security gap in the chip. In addition, non-erased flags point to a premature termination of the card programming, so that this information does not have to be obtained elsewhere.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a circuit configuration and a method for authenticating the content of a memory area, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Circuit configuration and method for authenticating the content of a memory area


A composite air and foam protective packaging product comprises a packaging cushion having, in cross-section, at least three plies of plastic film, foam between a first ply and a second ply of the three plies of plastic film, and air between the second ply and a third ply of the three plies of plastic film.

Various types of cushioning materials have heretofore been employed as protection for an item packaged for shipment. Two such types of cushioning materials are air cushions and foam cushions. An air cushion is formed from thin plastic film that is heat sealed along one or more edges to entrap air within it. An example of an air cushion is the AIRplus® air cushion, available from the assignee. A foam cushion is formed from thin plastic film that is heat sealed along one or more edges to contain expanding foam that is injected between two plies of the film. An example of a foam cushion and a machine for making it is disclosed in U.S. Pat. No. 5,727,370, hereby incorporated by reference herein as if fully set forth in its entirety.
Each of these two types of protective packaging has its own inherent advantages and disadvantages. One advantage of air cushions is that the fill material, air, has zero cost. On the other hand, the fill material of foam cushions, foam, has significant costs in its raw starting materials (two foam precursors). One advantage of foam cushions is that the freshly injected expanding foam of the cushion will mold itself to or around the item being packaged, thereby better protecting the item. On the other hand, an air cushion is unable to mold itself to or around the item being packaged. However, air cushions have greater resilience than foam cushions.
It is desirable to devise a packaging material that combines the advantages of both air cushions and foam cushions.

Composite air and foam protective packaging


A method is provided for enabling users to control various functions of an apparatus such as a television signal receiver in an easy and convenient manner. According to an exemplary embodiment, the method enables a user to control an apparatus via a user input device having a key capable of being rotated and pressed by the user. The method includes steps of enabling the user to control a first set of functions of the apparatus during a first mode by rotating and pressing the key responsive to an on-screen menu, and enabling the user to control a second set of functions of the apparatus during a second mode by rotating and pressing the key without providing the on-screen menu.

1. Field of the Invention
This application claims the benefit, under 35 U.S.C. §365 of International Application PCT/US2005/003470, filed Feb. 7, 2005, which was published in accordance with PCT Article 21(2) on WO2006/085850 A1 in English.
The present invention generally relates to user control techniques for an apparatus, and more particularly, to a method for enabling users to control various functions of an apparatus such as a television signal receiver in an easy and convenient manner.
2. Background Information
Apparatuses such as television signal receivers are often controllable by user input devices such as hand-held, wireless remote control devices and/or other user input devices. Current designs for such user input devices often include a relatively large number of keys/buttons to accommodate the many functions capable of being is provided by the apparatus. Such designs may, for example, include specific keys/buttons that are dedicated to controlling certain apparatus functions.
With the aforementioned type of user input device designs, it may be unduly complicated for users to control an apparatus. For example, users may become overwhelmed by the relatively large number of keys/buttons available for selection and/or may not understand the function provided by certain keys/buttons. Accordingly, users may avoid using many of the available keys/buttons of the user input device, other than those keys/buttons that they understand and are comfortable using and/or those keys/buttons that are necessary for the basic operation and control of an apparatus (e.g., on/off, etc.). As a result, users may be disadvantaged in that they fail to utilize the many available functions capable of being provided by an apparatus.
Accordingly, there is a need for a method for enabling users to control an apparatus such as a television signal receiver that avoids the foregoing problems, and thereby enables users to control a relatively large number of apparatus functions in an easy and convenient manner. The present invention addresses these and/or other issues.

Method for enabling user control of an apparatus


A phase plug for optimally matching a drive-unit's diaphragm to the throat of a waveguide is disclosed. Specific embodiments of a circular diaphragm matched to an elliptical waveguide and a circular diaphragm to a rectangular waveguide are disclosed.

1. Field of the Invention
The present invention relates to the design of the phase plug in an electro-acoustic transducer composed of the phase plug and drive-unit, and waveguide assemblies.
2. Description of Prior Art
In high performance audio playback systems it is common practice to use wave guiding devices coupled to an electro-acoustic transducer drive-unit (that portion of an electro-acoustic transducer that does the direct electrical to acoustical transduction) that act to both amplify and direct the sound energy created therein. These devices go by many names, the most common being "horns" and "waveguides", waveguides—a newer term—implies that more importance is given to the directivity controlling aspects of these devices than the loading ones. I will use the term waveguide consistent with its new meaning, but it is also my intention to mean any and all devices performing such tasks regardless of name.
The "shape" of the wavefront presented to the input aperture of the waveguide (the throat) has a great influence on how the device radiates sound from the open end (the mouth), particularly at the higher frequencies. Shape in the context of this application means the bounding area of a plane perpendicular to the sound channel propagation, it is a two dimensional surface, but it can also refer to the surface velocity distribution (complex number map) in that same surface. In order to control the formation of the throat wavefront it is common practice to place a plug containing multiple phase equalizing channels between the drive-unit diaphragm and the throat of the waveguide. This plug is usually designed so as to direct the sound waves emitted from the drive-unit diaphragm into the waveguide throat aperture in a prescribed shape. This plug is also know by various names, the most common being "phase plug", "phasing plug" or "equalizer".
The art of phase plug design is well advanced. The first significant disclosure of the function of a phase plug is provided by Wente, U.S. Pat. No. 2,037,187 (1936). Wente notes that the goal is to provide an essentially planar wavefront at the horn throat and he achieves this task by directing the sound through phase equalizing channels of essentially equal length, thereby ensuring that the contributions all add in phase.
In Henricksen, U.S. Pat. No. 4,050,541 (1977), discloses an alternate type of phase plug wherein the phase equalizing channels are radial, as opposed to more common circumferential.
Carlson, U.S. Pat. No. 4,718,517 (1988), discloses a phase plug which has a rectangular exit aperture at the throat end to better match the waveguide throat, but at the input end at the drive-unit diaphragm, the phase equalizing channels are also rectangular which is not ideal. Carlson recognizes the need for a phase plug when transitioning from a circular source to a non-circular one but does so utilizing only a single channel of non-varying cross section (obviously easy to fabricate) or he uses two phase equalizing channels which are still not ideally matched to the circular diaphragm. In the later case the phase equalizing channels vary only in size—not shape—as they progress, and they are not concentric. In terms of performance (but not necessarily so in terms of manufacturing case) Carlson's design is not optimal. The phase plug's phase equalizing channels entrance shape is not well matched to the diaphragm resulting in unequal phase propagation summation effects at the waveguide throat which will result in distortions of the sound.
Bie, U.S. Pat. No. 5,117,462 (1992), utilizes the voice coil motion as part of the radiating surface of the drive-unit and adds a sound channel to said radiating region. He also shows a phase plug with non-concentric round phase equalizing channels.
Finally, Keith, U.S. Pat. No. 6,064,745 (2000), discloses an improved radial type of phase plug which is easier to manufacture than previous designs. The input shapes are not circles, they are triangular.
Each of these inventions claims a distinct improvement over the others in regard to performance, manufacturability and/or some other comparable; however, none of them discloses a phase plug design which optimally matches a drive-unit's diaphragm shape to a waveguide throat of different shape (as can be required by waveguide theory). By using phase equalizing channels which transition gradually from circular at the diaphragm to non-circular at the exit an improved phase plug design can be implemented.
Adamson acknowledged in U.S. Pat. No. 4,975,965 (column 5, lines 56–64) that his phase plug "has been found to be particularly useful when applied to acoustic waveguide speakers of the variety developed by Dr. E. R. Geddes . . . "—the current inventor. The waveguide referred to by Adamson was based on the oblate spheroidal coordinate system. In Chapter 6 of my book Audio Transducers, (GedLee Publishing, July, 2002), I discuss the fact that there are several different coordinate systems which yield useful waveguides (see table 6.1 in the text) and that each one has a different set of radiation characteristics. As discussed in this text, these different waveguides require different wavefront shapes at the throat ("source aperture" and "curvature" in the table of my text) for optimum performance.
In order to optimally match a drive-unit to a waveguide, it is desirable to have a phase plug that adapts the motion of a generally circular diaphragm to a desired aperture shape in a manner which brings the velocities of various portions of the circular diaphragm to the exit aperture in a prescribed, but generally in-phase, manner. There are situations where the velocity distribution (the velocity shape) in the phase plug's exit aperture (the waveguides throat) may want to be non-uniform.
An preferred embodiment of the invention disclosed in this specification occurs when connecting a circular drive-unit to a waveguide that requires an elliptical throat aperture. The phase plug in this case should have a shape at the input end that is circular or annular such as concentric annular rings spaced so that each ring has the smallest path length to those diaphragm points which excite it, i.e. the shapes conform to the circular source. At the exit aperture the shapes are concentric elliptical rings, typically of equal area and arranged so that there combined shapes equal the shape required by the waveguides throat.
In none of the prior art is it recognized that the optimum phase plug would have the requirements highlighted above. It was generally assumed that the phase plug's exit aperture (the throat of the waveguide) should be circular, or one with an equally simple shape to fabricate so long as the shapes of the sound channels at the input and output ends remain constant. In most cases the waveguide throat is adapted to match the phase plug's exit aperture—not the other way around. The prior art generally conforms to a design approach where ease of manufacture is emphasized, steering away from more complicated sound channel shapes because of manufacturing concerns. Today, injection molding complex phase plugs in plastic is a relatively easy manufacturing process and so complex shapes need no be avoided and more effective phase plugs can be readily fabricated.


Method and systems of improving the response of public safety personnel to or evacuation from a desired location are provided. In addition to path information obtained through traditional sources, information is used to determine the optimal route for emergency personnel to an emergency situation and for aiding emergency personnel to route people from the situation. The information may also be used to automatically prioritize vehicles and personnel to optimize response time. Further, the information may also be used to in situations in which it is advantageous for the vehicle or personnel to be tactically positioned in nearby locations rather than at the incident scene. Although the descriptions below will primarily focus on routes to a particular location, similar methods can be used for evacuations from the location. The optimal route may use historical information stored in a database local or remote to the dispatcher and/or real-time information updated during the emergency situation.

With the advent of an information-based society and the explosion of internet users, the information available to the ordinary individual has increased dramatically over the last decade. Online maps are commonly used to find particular locations, as well as to determine the route with the shortest distance to a location. Some sites use additional information such as the posted speed limit to provide the route taking the least amount of time for the vehicle to traverse. However, this latter information may be of little value to public service providers (e.g., ambulance, fire, police) when a fast response is desired as their vehicles are able to ignore the speed limits.
Public service response vehicles and personnel are in fact usually dispatched to locations where their presence is urgently needed by a dispatcher (i.e., person at a central location); and in such situations response time is often critical. In such situations, the dispatcher (or individual in the public service vehicle) typically uses one or more sources of information to select the most effective set of roads for the vehicle or personnel to travel. This information mirrors that available online, e.g., the route having the shortest distance to traverse, and thus, presumably the fastest route for the vehicle. However, the information used to determine the shortest vehicular distance often lacks information that can be used to make a better decision and thus enable the vehicle or personnel to arrive at the desired destination sooner.
Moreover, in certain situations, such as crime scenes in which the criminal activity is ongoing, it may not be desirable for the public service vehicle to arrive at the destination indicated by the dispatcher. In these situations, it may instead be desirable for the vehicle to arrive in a nearby location. There is, at present, no mechanism exists in such situations for determining better positioning.