According to the invention there is provided an improved weightlifting aid and method of use thereof, comprising: a barbell supporting block element; and a plurality of barbell contacting arrangements for attaching different sides of the block element to a barbell; in which the one or more barbell contacting arrangements are releasably connectable to the barbell; so as to secure the block element to the barbell above the chest of a user performing a bench press exercise, the block element being of adjustable height depending on which part of the block element is attached to the barbell.

1. Field of the Invention
This invention relates to a weightlifting aid and a method of weightlifting, with particular reference to bench pressing and other weightlifting movements performed from a recumbent position.
2. Description of Related Art
Generally, to perform a bench press, a person lies in a recumbent position on a bench that is parallel or angled to the ground, grasps a barbell that is positioned on a rack above the person's head, lowers the barbell until it touches the person's chest, and then lifts the barbell to a position that is over the person's chest with the person's arms essentially fully extended. It is known that, for a variety of reasons, it can be desirable to initiate a bench press exercise from a range of starting positions higher than the user's chest. For instance, raising the starting position allows the user to perform a bench press exercise with heavier weights. To this end, a number of stackable wooden boards are commonly placed on a weightlifter's chest so that the minimum position of the barbell is at a desired distance from the weightlifter's chest. This practice requires at least one other person (commonly known as a "spotter") to be present to hold on to the boards.
In the prior art, a number of devices and/or methods have been proposed to allow the weightlifter to initiate a bench press from a range of starting positions without the need for a spotter—see for example, U.S. Pat. Nos. 6,224,518, 5,433,686, and 5,897,468. In particular, U.S. Pat. No. 6,224,518 describes a method for reducing shoulder injury during the performance of a bench press exercise. The method entails the use of a cylindrical pad adapted to be coupled to a barbell substantially over the chest of a user, and having sufficient thickness to prevent a user performing a bench-press-type exercise from lowering his or her upper arms below a horizontal plane defined by the user's back. This method and device have the sole purpose and function of ensuring that a user performing a bench press lowers the barbell to the point where the upper arms descend to the horizontal plane defined by the back of the user. The thickness of the cylindrical pad is fixed and cannot be adjusted. Thus, the method disclosed in U.S. Pat. No. 6,224,518 does not allow the user to initiate a bench press from a range of starting positions. This is a significant limitation, as raising the height of the starting position for a bench press allows the user to perform the movement with heavier weights.
Similarly, U.S. Pat. No. 5,897,468 describes a training aid which is intended to reduce the risk of injury to the arm and shoulder of a user and provide assistance to a user who is attempting to lift a somewhat increased weight. The training aid disclosed in U.S. Pat. No. 5,897,468 comprises a harness having a pair of relatively small spaced apart pockets. A plurality of spacers can be stored in each pocket to an overall height of up to about 4 cm in order to prevent the barbell from touching the chest of the user, thereby rendering the weightlifting exercise easier. Another embodiment is proposed in which a single pair of spaced apart spacers are attached to the training aid using a hook and loop fastener material.
U.S. Pat. Application No. 20120165163 A1 describes a weightlifting aid having a harness for attaching the aid to the chest area of the user; a base region in connection with the harness; and a plurality of interconnectable board elements; in which at least one board element is also connectable to the base region, so as to form a stack of board elements on top of the user's chest, the stack being of adjustable height depending on the number of barbell supporting boards used to form the stack. Thus, the user may initiate a bench press from a range of starting positions by adding to or subtracting from the number of board elements stacked on the user's chest.
The weightlifting aid described in U.S. Pat. App. No. 20120165163 A1 is highly impractical and potentially unsafe for several reasons. First, a user wishing to initiate a bench press from a range of starting positions is required to engage in a cumbersome and time consuming process of adding and removing boards from a stack of boards strapped to the user's chest. The fact that the user must remain lying on his or her back (to prevent the stack from falling over) while adding or removing boards further compounds the cumbersome and potentially dangerous nature of this aid. Second, the aid comprises several board elements of considerable size and weight, which would make transporting the aid to a gym extremely impractical or impossible. For instance, the boards would not likely fit into a duffle bag or backpack, and transporting the aid in multiple bags would be impractical and undesirable for many users, particularly those users who travel by foot, bicycle, or public transportation. Third, use of the weightlifting aid in U.S. Pat. App. No. 20120165163 A1 requires a vertical alignment of the board elements stacked on the user's chest with the vertical path of the barbell during exercise. Because the vertical path of the barbell is necessarily perpendicular to the floor, use of the aid is limited to exercises in which the user's body is in a recumbent position parallel to the floor. Thus, the weightlifting aid disclosed in U.S. Pat. App. No. 20120165163 A1 aid could not be used for exercises performed on an incline or decline bench, as the angled position of the user's chest in relation to the vertical path of the barbell during exercise would prevent the stacked board elements from aligning with the barbell during exercise. This presents a significant limitation for users wishing to perform bench press exercises from a variable range of starting locations on an incline or decline bench.
The present inventor has realized that there is a need for a device which can be used by a weightlifter to perform a range of bench press type exercises at a significant and variable range of heights and angles, which can be used safely and efficiently without the assistance of another person, and which is small, lightweight, and can be easily transported or stored in a small duffle bag.
According to a first aspect of the invention there is provided a weightlifting aid including: a barbell supporting block element and a plurality of barbell contacting arrangements for attaching the block element to a barbell; in which the one or more barbell contacting arrangements are releasably connectable to the barbell; so as to secure the block element to the barbell above the chest of a user, the block element being of adjustable height depending on which side of the block element is attached to the barbell.
In this way, the above described needs can be met. In contrast, the training aid of U.S. Pat. No. 5,897,468 acts as a stop block for the barbell close to the chest of the user, and does not suggest that a range of beneficial and differing exercises can be performed by providing a taller platform of variable height. In any event, the use of two separate and rather thin spacers as proposed in U.S. Pat. No. 5,897,468 are unlikely to prove to be sturdy, certainly at significant clearances from the user's chest, and could easily topple should a heavy weight be rested on them, or if the barbell is lowered at an angle or with a twisting motion. This could cause serious injury to the weightlifter.
The skilled reader will appreciate that the block element of the present invention does not necessarily have a weight bearing impact on the chest area of the user, but rather may be lightly touched to the user's chest before initiating the bench press movement. Further, because the present invention attaches to the barbell rather than to the chest of the user, it easily accommodates multiple users. In contrast, the training aids U.S. Pat. No. 5,897,468 and U.S. Pat. App. No. 20120165163 A1 each require the user to don a harness apparatus to which boards or spacers must be secured. The harness structure makes these aids impractical and cumbersome for use by multiple persons, such as training partners, as the harness must removed and refitted, and the boards or spacers removed and reinstalled, for each successive user. This time-consuming process may be undesirable for users having limited time for exercise. Such users are likely to prefer the ease and efficiency of the aid of the present invention, which does not involve a harness that must be removed and refitted, or boards or spacers that must be removed and reinstalled.
Further, the aid of the present invention may be used to be perform bench press exercises on an incline or decline bench, as well as on a flat bench. In contrast, the use of aids which require boards or spacers to be stacked on the users chest, such as those described in U.S. Pat. No. 5,897,468 and U.S. Pat. App. No. 20120165163 A1, is limited to exercise performed on a flat bench, in which the user's body is in a recumbent position parallel to the floor. These aids do not allow use on an incline or decline bench, as the angled position of the user's chest in relation to the vertical path of the barbell during exercise would prevent the stacked boards or spacers from aligning with the barbell during exercise.
For these and other reasons, the aid of the present invention provides a significant and much needed improvement over the prior art.


Isolation for antennas in a wireless communication system is achieved between transmit and receive paths for a multiple input multiple output (MIMO) antenna array by separating a first transmit path from an associated receive path to be matched with a second transmit path and matching the first receive path with the second receive path. It is expected that the two transmit paths operate on sufficiently different frequencies that there is minimal interference there and the additional spacing from the transmit path to the receive path will reduce interference therebetween without increasing a footprint of the antenna array.

The technology of the disclosure relates to improving isolation between uplink and downlink channels at a wireless transceiver.
Wireless communication is rapidly growing, with ever-increasing demands for high-speed mobile voice and data communication. Information is embedded in an electromagnetic signal generally within the radio frequency range of the electromagnetic spectrum. This electromagnetic signal is transmitted from a transmitter, through a first antenna, across any intervening space, to a second receiver through a second antenna. In many instances the transmitter is actually a first transceiver and the receiver is actually a second transceiver and signals are exchanged bi-directionally. Depending on point of view, one such signal may be considered an uplink signal, and the other signal may be considered a downlink signal.
In the early days of wireless communication there was generally perceived to be ample room within the electromagnetic spectrum for many such signals to coexist without interference between signals. As the complexity of the signals has increased, in part due to the increasing amounts of information placed into the signals, the electromagnetic spectrum has become relatively crowded, particularly in the radio frequency range. Accordingly, uplink signals are typically relatively close in frequency to downlink signals for bi-directional communication.
To help isolate uplink signals from downlink signals at a transceiver, there are currently a variety of solutions. One such solution is a time-based approach (e.g., time division multiplexing) that prevents simultaneous use of uplink frequencies and downlink frequencies. While effective, this approach has fallen out of favor as more information is sent in each direction making simultaneous use of the frequencies almost a requirement. Another solution is the use of a duplexer that provides isolation between uplink and downlink frequencies. An exemplary conventional transceiver 100 using a duplexer is illustrated in FIG. 1.
In particular, the transceiver 100 includes a transmit (Tx) path 102 where a signal 104 to be transmitted enters a field programmable gate array (FPGA) circuit 106 for processing and is passed through a digital-to-analog converter (DAC) 108 and an amplifier 110 to a duplexer 112. From the duplexer 112, the converted, amplified signal 104 is passed to an antenna 116 and transmitted. The transceiver 100 further includes a receive (Rx) path 118. Signals are received at the antenna 116, passed through the duplexer 112, through an amplifier 120 and an analog-to-digital (ADC) converter 122 to the FPGA 106 for processing to become a receive signal 124.
At its simplest, a duplexer is a device that allows bi-directional (i.e., duplex) communication over a single path. In the transceiver 100, the duplexer 112 isolates the receiver portion from the transmitter portion while permitting them to share a common antenna. In radio frequency communication, transmit and receive signals typically occupy different frequency bands, and so the duplexer 112 may have frequency selective filters. Modern communication often uses nearby frequency bands, so the frequency separation between transmit and receive signals is relatively small.
While duplexers may be effective at providing desired isolation, as the frequencies get closer and, particularly in the frequencies of interest, the cost of such duplexers has increased to levels that are not commercially practical. For example, such elements may cost around sixty to ninety U.S. dollars. For high frequency broadband duplexers, that cost may readily exceed one hundred U.S. dollars, and in some cases exceed three hundred U.S. dollars. Such costs are generally perceived to be unacceptable within most commercial industries.
A third solution is the use of interference cancellation calculations that may be performed in an FPGA circuit cooperating with a multiple input/multiple output (MIMO) antenna array such as illustrated in FIG. 2. In particular, a transceiver 200 may include an FPGA 202 that controls four antennas 204(1)-204(4). Antennas 204(1)-204(2) handle MIMO stream A, and antennas 204(3)-204(4) handle MIMO stream B. For MIMO stream A, the antenna 204(1) acts as the antenna for a transmit path 206(1), and the antenna 204(2) acts as the antenna for a receive path 206(2). The transmit path 206(1) includes a DAC 208 and an amplifier 210. Similarly, the receive path 206(2) has an ADC 212 and an amplifier 214. Further, a tap 216 is associated with the antenna 204(1) and provides a signal to an interference cancelation circuit 218 within the FPGA 202. Likewise, for MIMO stream B, the antenna 204(3) acts as the antenna for a transmit path 220(1), and the antenna 204(4) acts as the antenna for a receive path 220(2). The transmit path 220(1) includes a DAC 222 and an amplifier 224. Similarly, the receive path 220(2) has an ADC 226 and an amplifier 228. Further, a tap 230 is associated with the antenna 204(3) and provides a signal to an interference cancelation circuit 232 within the FPGA 202. The interference cancelation circuits 218 and 232 operate to subtract or otherwise remove the transmit signal from the received signal of the respective paths. This subtraction is done because the signal emanating from the transmit antennas 204(1), 204(3) may be received at the receive antennas 204(2), 204(4). By subtracting such received signals, the original received signal may be restored.
MIMO antenna arrays necessarily physically space antennas from one another to help isolate signals. While effective, as the number of antennas increases, the size penalty that the physical separation requires becomes impractical. This complexity is exacerbated when there is a dual band requirement for the MIMO antenna array, such as may occur in a distributed communication system (e.g., a centralized radio access network (cRAN) or distributed antenna system (DAS)). Such a situation is illustrated in FIG. 3, where a cRAN 300 has a digital routing unit (DRU) 302 coupled to a low band baseband unit (BBU) 304 and a high band BBU 306. Both the low band BBU 304 and the high band BBU 306 handle (at least) two data streams (MIMO A and MIMO B) each having an uplink (UL) and a downlink (DL) component. Thus, for the low band BBU 304, there is data stream DL MIMO A, which goes from the low band BBU 304, through the DRU 302 to a low band section 308(1) of a transceiver system 310. As with the transceiver 200 of FIG. 2, the DL MIMO A goes to an FPGA 312 and is sent through a DAC 314 and an amplifier 316 before transmission from an antenna 318. UL signals are received at an antenna 320, provided to an amplifier 322, converted in an ADC 324, and then provided to the FPGA 312. The UL signals are then passed to the low band BBU 304. Similarly, the DL MIMO B goes to the FPGA 312 and is sent through a DAC 326 and an amplifier 328 before transmission from an antenna 330. UL signals are received at an antenna 332, provided to an amplifier 334, converted in an ADC 336, and then provided to the FPGA 312. The UL signals are then passed to the low band BBU 304. As noted by signals I1 and I2, the signals transmitted from the antenna 318 may impinge on the antennas 320 and 332. Likewise, the signals 13 and 14 from the antenna 330 may impinge on the antennas 320 and 332. To reduce this interference, there is a tap 338 that collects information about the signal being sent from the antenna 318 and a tap 340 that collects information about the signal being sent from the antenna 330. These taps 338 and 340 feed interference cancelation circuits 342 and 344, respectively, which calculate an offset in a fashion similar to the transceiver 200, albeit taking into account both possible interfering signals.
With continued reference to FIG. 3, for the high band BBU 306, the DL MIMO A goes to an FPGA 346 in high band section 308(2) of the transceiver system 310 and is sent through a DAC 348 and an amplifier 350 before transmission from an antenna 352. UL signals are received at an antenna 354, provided to an amplifier 356, converted in an ADC 358, and then provided to the FPGA 346. The UL signals are then passed to the high band BBU 306. Similarly, the DL MIMO B goes to the FPGA 346 and is sent through a DAC 360 and an amplifier 362 before transmission from an antenna 364. UL signals are received at an antenna 366, provided to an amplifier 368, converted in an ADC 370, and then provided to the FPGA 346. The UL signals are then passed to the high band BBU 306. As noted by signals 15 and 16, the signals transmitted from the antenna 352 may impinge on the antennas 354 and 366. Likewise, the signals 17 and 18 from the antenna 364 may impinge on the antennas 354 and 366. To reduce this interference, there is a tap 372 that collects information about the signal being sent from the antenna 352 and a tap 374 that collects information about the signal being sent from the antenna 364. These taps 372 and 374 feed interference cancelation circuits 376 and 378, respectively, which calculate an offset in a fashion similar to the transceiver 200, albeit taking into account both possible interfering signals.
It should be appreciated that the calculations done by the interference cancelation circuits 342, 344, 376, and 378 may become more complex as the MIMO array expands past two bands or more than two antenna pairs. This complexity may add latency or otherwise impact performance and ultimately may become impractical as a solution.
Various industries have wrestled with the problem of signal isolation, but one industry that is seeing heavier use, and thus beginning to direct more attention to this issue, is in, as alluded to in the discussion of FIG. 3, distributed communication systems. An exemplary distributed communication system may be a distributed antenna system (DAS) within a building that provides wireless connections to mobile terminals within the building in places where an outside signal may be blocked or where traffic dictates that a small cell may be appropriate.
One approach to deploying a wireless communication system involves the use of radio frequency (RF) antenna coverage areas, also referred to as "antenna coverage areas." Antenna coverage areas can have a radius in the range from a few meters up to twenty meters as an example. Combining a number of access point devices creates an array of antenna coverage areas. Because the antenna coverage areas each cover small areas, there are typically only a few users (clients) per antenna coverage area. This allows for minimizing the amount of RF bandwidth shared among the wireless system users. It may be desirable to employ optical fiber to distribute communication signals. Benefits of optical fiber include increased bandwidth.
One type of distributed antenna system for creating antenna coverage areas includes distribution of RF communication signals over an electrical conductor medium, such as coaxial cable or twisted pair wiring. Another type of distributed antenna system for creating antenna coverage areas, called "Radio-over-Fiber," or "RoF," utilizes RF communication signals sent over optical fibers. Both types of systems can include head-end equipment coupled to a plurality of remote units (RUs), which may include an antenna and may be referred to as a remote antenna unit or RAU. Each RU provides antenna coverage areas. The RUs can each include RF transceivers coupled to an antenna to transmit RF communication signals wirelessly, wherein the RUs are coupled to the head-end equipment via the communication medium. The RF transceivers in the RUs are transparent to the RF communication signals. The antennas in the RUs also receive RF signals (i.e., electromagnetic radiation) from clients in the antenna coverage area. The RF signals are then sent over the communication medium to the head-end equipment. In optical fiber or RoF distributed antenna systems, the RUs convert incoming optical RF signals from an optical fiber downlink to electrical RF signals via optical-to-electrical (O-E) converters, which are then passed to the RF transceiver. The RUs also convert received electrical RF communication signals from clients via the antennas to optical RF communication signals via electrical-to-optical (E-O) converters. The optical RF signals are then sent over an optical fiber uplink to the head-end equipment.
While some RUs are simple antennas that merely bring an existing cellular-type service into an area with poor reception (e.g., inside large buildings), other RUs may be more robust and may actually act as a fully functional cell (e.g., a picocell, femtocell, microcell, or the like) with registration, hand-off, and other traditional cellular functions. Still other RUs may act as some form of hybrid with some, but not all functions of a traditional cell, but more functionality than a simple antenna.
An exemplary distributed communication system is provided with reference to FIG. 4 to provide additional context. In this regard, FIG. 4 illustrates distribution of communication services to remote coverage areas 400(1)-400(N) of a wireless distribution system (WDS, also referred to herein as a distributed communication system, a distributed antenna system (DAS), or wireless communication system (WCS)) 402, wherein 'N' is the number of remote coverage areas. These communication services can include cellular services, wireless services, such as RF identification (RFID) tracking, Wireless Fidelity (WiFi), local area network (LAN), and wireless LAN (WLAN), wireless solutions (Bluetooth, WiFi Global Positioning System (GPS) signal-based, and others) for location-based services, and combinations thereof, as examples. The remote coverage areas 400(1)-400(N) are created by, and centered on, remote units 404(1)-404(N) (sometimes these may be low power remote units (LPR), but are more commonly referred to herein as just a remote unit (RU) or remote antenna unit (RAU)) connected to a central unit 406 (e.g., a digital routing unit (DRU) a head-end controller, a head-end unit (HEU), or the like). The central unit 406 may be communicatively coupled to a signal source 408, for example, a base transceiver station (BTS) or a baseband unit (BBU). The communicative coupling may be wireless (e.g., such as through a cellular network) or over a wire-based/fiber-based system (e.g., such as through some form of telephony network backbone or the Internet). When the signal source 408 is a BBU, the signal source 408 may communicate with the central unit 406, which may be a DRU, using digital communication protocols such as the common public radio interface (CPRI). In this regard, the central unit 406 receives downlink communication signals 410D from the signal source 408 to be distributed to the remote units 404(1)-404(N). The remote units 404(1)-404(N) are configured to receive the downlink communication signals 410D from the central unit 406 over a communication medium 412 to be distributed to the respective remote coverage areas 400(1)-400(N) of the remote units 404(1)-404(N). In a non-limiting example, the communication medium 412 may be a wired communication medium, a wireless communication medium, or an optical fiber-based communication medium. While wireless is possible, exemplary aspects of the present disclosure are well-suited for situations where the medium is a physical conductor (electrical, optical, or some other waveguide (e.g., a wireless microwave system may still use a microwave waveguide)). Each of the remote units 404(1)-404(N) may include an RF transmitter/receiver (not shown) and a respective antenna 414(1)-414(N) operably connected to the RF transmitter/receiver to distribute wirelessly the communication services to client devices 416 within the respective remote coverage areas 400(1)-400(N). The remote units 404(1)-404(N) are also configured to receive uplink communication signals 410U from the client devices 416 in the respective remote coverage areas 400(1)-400(N) to be distributed to the signal source 408. The size of each of the remote coverage areas 400(1)-400(N) is determined by an amount of RF power transmitted by the respective remote units 404(1)-404(N), receiver sensitivity, antenna gain, and RF environment, as well as by RF transmitter/receiver sensitivity of the client devices 416. The client devices 416 usually have a fixed maximum RF receiver sensitivity, so that the above-mentioned properties of the remote units 404(1)-404(N) mainly determine the size of the respective remote coverage areas 400(1)-400(N).
With reference to FIG. 4, the central unit 406 may include electronic processing devices, for example an FPGA, a digital signal processor (DSP), and/or a central processing unit (CPU), for processing the downlink communication signals 410D and the uplink communication signals 410U. Likewise, each of the remote units 404(1)-404(N) also employs electronic processing devices for processing the downlink communication signals 410D and the uplink communication signals 410U. Further, the communication medium 412 is only able to carry the downlink communication signals 410D and the uplink communication signals 410U up to a maximum bandwidth. Collectively, the processing capabilities of the electronic processing devices in the central unit 406, the processing capabilities of the electronic processing devices in the remote units 404(1)-404(N), and the maximum bandwidth of the communication medium 412 provide the system resources available in the WDS 402. In practice, the remote units 404(1)-404(N) and the client devices 416 may each have a transceiver with frequency isolation concerns.
No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.

Systems and methods for providing isolation for antennas in a wireless communication system

Corning Research & Development Corporation


A rotor blade (1) is disclosed which recenters itself in relation to the rotatable hub in which it is installed. Imposition of an external force (A) upon the rotor blade (1) creates a moment (M) which acts about the rotor blade's root (2). Recentering is accomplished by centrifugal forces acting through an offset distance (C) resulting from rotation of the blade root (2) about a shaped retaining pin (6), achieving an enhanced opposing restorative moment (M') on the rotor blade (1). The rotor blade (1) contains an arcuate bearing suface (8) within a chordwisely disposed slot (7) in the rotor blade's root (2). This arcuate surface (8) bears against a mating arcuate surface (9) with a smaller radius of curvature lengthwise disposed on the shaped retaining pin (6).

Rotary machines contain rotor blades installed in rotatable hubs or disks in axial orientation. These rotor assemblies typically contain a plurality of aerodynamically shaped blades, or airfoils, which operate at high speeds and in hostile environments. As a result, the rotor blades are subjected to steady and vibratory loads which generate significant internal and external stresses.
Properly designed rotor blades can accommodate most known loads, resulting in the long and safe operation of the rotary machine. These loads are derived from inertial and aerodynamic sources. Inertial loading depends on rotor blade mass and stiffness distribution, and impacts the vibratory response and frequency tuning of the rotary machine. Aerodynamic loading depends on both steady state and disturbed air flow through the rotary machine. These loads then cause a variety of stresses, such as centrifugal, bending, and torsion, as well as vibratory bending, on the rotary machine. In the case of vibratory bending stresses, it is known that frequency tuning of the rotor blade aids in the control of vibratory response to unsteady loading.
The main source of steady state internal stresses in rotating parts within a rotary machine is centrifugal force. In a rotary machine any typical cross-sectional area of the rotor blade must restrain the centrifugal force acting on all of the material beyond its own radial location in relation to the machine's axis of rotation. It necessarily follows that the largest forces sustained by a rotor blade occur in the blade's root structure. These forces are then transferred through a rotor blade retention apparatus to a centrally-located rotatable hub. In a pinned-root rotor blade these forces are passed from the rotor blade root through retention tenons which are attached to the retention member which is secured to the rotatable hub.
Additional sources of blade stress include foreign object contact, changes in flight altitude and attitude, as well as aircraft-induced shock and vibration. In particular, propulsor blades mounted in an aft position as called for in some aircraft designs are more susceptible to foreign object damage than are normal wing-mounted propulsors. Damage to those aft-mounted blades may be caused by collisions with runway water and slush, ice, sand, stones, and other debris kicked up by the aircraft's tires. Another potentially serious cause of damage to propulsor blades is in-flight bird strikes.
An important problem with rotor blades is accommodation of the aforementioned stresses when the blade is subjected to the operational and adverse stressing conditions described above.
The related art generally teaches the use of a pinned-root engagement to securely capture the blade to the rotor hub, and reduce or relieve root bending stresses. However, pinned-root attachments may experience frictional sliding of blade roots against their retention tenons and retaining pins as installed in a rotatable hub, which may result in undesirable heating, wear, and fretting of the mating surfaces and underlying structures. Also, this type of engagement provides limited accommodation of the external stresses and moments imposed on the blade upon contact with foreign objects. These problems have impeded desired extension of rotor blade service life.
What is needed is a new pinned-root design which can minimize and/or accommodate those forces, moments, and angular excursions of the rotor blade about the pin axis which cause undesirable wear and fretting of a rotor blade in the general vicinity of its connection to a rotatable hub.


In a method of preventing doming phenomena, luminance histogram distribution values are obtained (10) from a luminance signal, the various luminance histogram distribution values are processed and normalized (12), the luminance histogram distribution values are processed (16) to correct for at least actual contrast and brightness settings to obtain corrected histogram data, a beam current is predicted (18) from the corrected histogram data, and a correction signal is derived (20) from the predicted beam current and making said correction signal effective in the processing and normalizing step (12).

1. Field of the Invention
The invention relates to a method and device for preventing doming phenomena. More specifically, the invention relates to circuitry for preventing doming phenomena in a television receiver.
2. Description of the Related Art
European Patent Application No. EP-A-0,525,976, corresponding to U.S. Pat. No. 5,315,389, describes a prior art intensity control circuit for providing conventional intensity correction and has nothing to do with the prevention of dooming phenomena.
Doming phenomena may occur in case a section of the shadow mask of a cathode ray picture tube is irradiated with high intensity electron beams causing partial distortion of the shadow mask whereby a xe2x80x9cdomexe2x80x9d is formed in the mask. The effect thereof is mis-coloring which is very annoying. Because of the geometry of the tube, the influence of the doming phenomena is rather strong near the periphery of the screen where the electron beam strikes the shadow mask at a relatively large deflection angle.
Electron beams with high intensity are generated in correspondence to a local high luminance signal. To prevent doming phenomena, the luminance signal has to be controlled such that the intensity of the resulting electron beam is limited at least in those regions of the screen where doming is likely to occur.
Circuits which are specifically designed to prevent doming phenomena are already known from the prior art. An example is described in European Patent Application No. EP-A-0,354,518, corresponding to U.S. Pat. No. 4,996,590. The circuit described therein comprises means for processing the luminance signal including a low-pass filter for filtering out only the low frequent components of the luminance signal which, in a first comparator, are compared with a first reference signal related to the horizontal and vertical modulation signals, resulting in a control signal for a charge/discharge circuit which will tend to charge if there are areas on the screen where the luminance will be so high that doming phenomena will appear. The output of this charge/discharge circuit is compared with a second reference level signal resulting into a correction signal, which is used to adapt either the contrast or the luminance of the screen to counteract any doming phenomena.
In this prior art circuit, the first reference signal is generated such that the allowed luminance level is rather large at the center of the screen and is relatively small near the sides of the screen, thereby taking into account that the doming phenomena will appear predominantly near the edges of the screen and not in the center thereof.
It is, inter alia, an object of the invention to provide an improved doming phenomena prevention.
In a method of preventing doming phenomena in accordance with a first aspect of the present invention, luminance histogram distribution values are obtained from a luminance signal, the various luminance histogram distribution values are processed and normalized, the luminance histogram distribution values are processed to correct for at least actual contrast and brightness settings to obtain corrected histogram data, a beam current is predicted from the corrected histogram data, and a correction signal is derived from the predicted beam current and making said correction signal effective in the processing and normalizing step. Preferably, local doming is prevented by determining local histograms to correct local beam currents for at least two windows (32, 34 in FIG. 2).
Advantageously, a doming phenomena preventing circuit in accordance with the present invention, makes predominantly use of a processor performing calculations on luminance data which are already available in the a histogram memory forming part of the normal intensity control circuit. In many cases, a processor is already present and if said processor has a sufficient spare capacity, the doming preventing circuit according to the invention can be realized without adding any substantial hardware to the television receiver circuit. Loading a suitable program into the already present processor to calculate a correction signal from the available data would then solve a major part of the problem.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.


Various embodiments are disclosed relating to techniques to provide neighbor information in wireless networks and/or techniques to provide measurement pilot transmission information in wireless networks. According to an example embodiment, a neighbor report may be received from a first wireless node, the neighbor report including at least measurement pilot transmission information for one or more other wireless nodes. According to an example embodiment, a signal measurement technique for measuring signals from at least one of the one or more other wireless nodes may be determined based, at least in part, upon the neighbor report. According to another example embodiment, a message may be received from a first wireless node, the message including measurement pilot transmission information for the first wireless node. A signal measurement technique for measuring signals from the first wireless node may be determined based, at least in part, upon the received message.

Wireless networks, such as wireless local area networks (WLAN) typically communicate via radio or other frequencies. In a WLAN, for example, mobile stations are typically moving around, and may communicate with an access point (AP) or base station. The AP is typically a fixed device that may (or may not) be connected to infrastructure networks or wired networks.
The most common WLAN technology is described in the Institute of Electrical and Electronics Engineers IEEE 802.11 family of industry specifications, such as specifications for IEEE 802.11b, IEEE 802.11g and IEEE 802.11a. A group of 802.11 mobile stations may be in communication with each other (either directly or through one AP) in a network known as a basic service set (BSS), which may be identified by a basic service set identifier (BSSID). A group of BSSs (e.g., with one AP per BSS) may be coupled together in a larger WLAN network (e.g., with multiple APs) known as an extended service set (ESS), which may be identified by a service set ID (SSID).
When a mobile station moves around a wireless network (e.g., WLAN), the station may need to change its present association from one AP to another AP if the signal reception level, of the presently associated (serving) AP becomes too low and/or another AP provides a better signal level or capabilities. This procedure is known as roaming, and allows a mobile station to switch association among APs.
Before roaming or associating with a new AP, a mobile station may first locate one or more APs. There are a number of known techniques for measuring or monitoring radio signals to allow roaming between APs. Signals transmitted by APs may generally be monitored, and the received signal strength (RSS) may be measured for each AP, for example. In particular, APs may be located, for example, via passive scanning and by active scanning,
In passive scanning, a wireless station may monitor one or more channels to determine if there is a beacon or probe response transmitted by APs. A beacon may be transmitted by each AP at regular intervals (known as beacon intervals), e.g., every 100 ms. A beacon (or beacon signal) may include, for example, an AP timestamp, a BSSID identifying a specific WLAN network, a traffic indication map (TIM), beacon interval (or amount of time between beacon transmissions), an indication of the supported data rates, parameter sets or information about specific signaling methods that are supported, capability information (such as whether Wired Equivalency Privacy or WEP protocol is supported), and other information. In passive scanning, a node may listen for beacons or probe responses on each of a plurality of channels, gathering information on each AP such as received signal strength, capabilities and data rates of the AP, etc. In some instances, passive scanning may expend time and power while a node is listening for a beacon or probe response that may never occur or while the node may be listening to an idle channel.
Active scanning may involve a mobile station transmitting a probe request to one or more specific APs, and receiving probe responses from the APs. Active scanning allows mobile stations to interact with APs or other stations to obtain information. A mobile station may transmit, for example, a probe request that specifies a service set identity (SSID) in the probe request frame. Any AP or station on the channel that matches the SSID may, for example, respond with a probe response. The probe response, similar to a beacon, may provide information that may be useful to allow a station to access the network or associate with an AP. When compared to monitoring of beacons (passive scanning), active scanning may, in some cases, result in longer battery life (e.g., may consume less battery power), but also may reduce network capacity due to the probe request/probe response traffic.
In some WLAN networks, it has been proposed for APs to provide a neighbor report to a wireless station, in some cases. A neighbor report may be transmitted, for example, from an AP to a wireless station to provide the station with information regarding other (e.g., neighbor) access points (APs). These proposed neighbor reports may include information relating to for example the frequency band and channel where the reported APs are located, PHY type of the reported APs, synchronization information and information of the beacons, such as beacon intervals.
It has also been recently proposed for APs to transmit measurement pilots (which sometimes may be referred to as gratuitous probe responses). An AP may typically transmit a measurement pilot frame much more frequently (e.g., every 10 ms) than a beacon (e.g., every 100 ms) to provide more frequent information to stations. Thus, because the measurement pilot frame interval is typically much shorter than a beacon interval, stations may use measurement pilot frames to detect whether there is an AP transmitting on the channel, to measure the channel quality (e.g., measure received signal strength), and to receive other information relating to the AP in a much shorter period of time, e.g., as compared to waiting for the next beacon on the channel. Thus, at least in some cases, measurement pilot frames may facilitate quicker roaming decisions and association to a new AP. The measurement pilot frame may contain much of the same information provided in a beacon or probe response, but the measurement pilot is shorter since it may not include some of the longer fields in the beacon (such as TIM and DTIM fields).

Techniques to provide measurement pilot transmission information in wireless networks


Dissipative structures include at least one panel and a cell structure disposed adjacent to the at least one panel having interconnected cells. A deformable material, which may comprise at least one hydrogel, is disposed within at least one interconnected cell proximate to the at least one panel. Dissipative structures may also include a cell structure having interconnected cells formed by wall elements. The wall elements may include a mesh formed by overlapping fibers having apertures formed therebetween. The apertures may form passageways between the interconnected cells. Methods of dissipating a force include disposing at least one hydrogel in a cell structure proximate to at least one panel, applying a force to the at least one panel, and forcing at least a portion of the at least one hydrogel through apertures formed in the cell structure.

Explosive forces and high pressure shock pulses caused by an explosive device or system such as ordnance (e.g., projectiles, bombs, missiles, etc.) or another type of gas or chemical explosion, whether intentional or accidental, may cause substantial damage, injuries, and death. Blast dissipative structures are becoming increasingly desired for use in protecting items of value from the effects of such high pressure impulses.
In order to be effective, blast dissipative structures must absorb and dissipate significant amounts of energy to prevent damage from the pressure impulse generated by an explosion. Concrete has been employed in the past to make a passive standoff barrier to withstand the destructive force of an explosion, such as the detonation of a bomb. However, barriers made from concrete take time to construct and once constructed are permanent. Also, rigid concrete barriers do not absorb or dissipate shock pressure effectively. Instead, such barriers efficiently transmit the incident shock pressures through the barrier and apply pressure loading to the elements disposed on the other side of the barriers. As the result of the efficient transmission of the shock pressure pulse, rigid concrete barriers may spall and create harmful flying debris and/or may, in later time, crumble and create damaging falling debris. One method to absorb pressure pulses created by explosion has been to use water filled barriers. Blast dissipative structures using water-based technology are disclosed, for instance, in U.S. Pat. No. 4,836,079. As disclosed therein, bomb blast inhibitors can be inflated with air, placed around a bomb, and then filled with water, the water then acting to suppress or otherwise mitigate against the effects of any ensuing explosion. However, use of liquids having a relatively low viscosity (e.g., water) generally, if permitted, will flow to the regions of lowest potential energies as directed by gravity. Consequently, the use of such liquids requires that the liquid be contained in a desired initial configuration and limits the configuration and application of structures utilizing such a liquid. Moreover, the barrier needs to be erected where there is an adequate water supply. The barriers are often bulky which can pose transportation problems and add to the cost of using them and render them undesirable for utilization by a vehicle or by personnel.
Other attempts to provide blast dissipative structures are described in U.S. Pat. Nos. 7,575,797 and 6,200,664. 7,575,797 describes a blast reducing structure including a plurality of webs forming discrete funnel-shaped container elements containing volumes of liquid or deformable materials, such as liquids or materials. The liquid or deformable materials in the discrete container elements are constrained initially by a grommet, plug, or other sealing member and flow upon rupture from impact pressures. Alternate container elements formed by the webs are air-filled so as to accept the expelled liquid from adjacent container elements. The liquids or deformable materials flow through apertures formed in each of the plurality of webs to absorb impact energy.
U.S. Pat. No. 6,200,664 describes a structure for containing an explosion including a plurality of truncated polyhedral container elements secured to and projecting from a base sheet. Each polyhedral element is filled with a liquid, such as water, and is constructed to collapse in the event of an explosion. An opening in each of the polyhedral container elements is sealed by a burst disk or a removable seal that opens in the event of an explosion. The opening is sized to effect a misting action of the liquid therein when it is ejected from the openings by the collapse of the polyhedral container elements caused by the explosion. The liquid mist serves to absorb and dissipate the heat and energy of the explosion.
As mentioned above, each of the devices described in U.S. Pat. Nos. 7,575,797 and 6,200,664, utilize single rows of discrete container elements having a flowable liquid or deformable material disposed therein. Such elements require the use of a sealing member, such as a plug to contain the liquid or deformable material within the element prior to impact. Furthermore, the single rows of sealed, discrete container elements only expel the liquid or deformable material into an adjacent volume or element. During an impact, such configurations will only release the liquid or deformable materials from the container elements that were directly contacted by the impact of the force with sufficient magnitude. The liquid or deformable materials could also be released accidentally by evaporation and expansion of the liquid and gas.

Dissipative structures and related methods


Processing apparatus for photographic film, particularly intraoral xray film, in which the various processing stations are positioned in a circle about a central rotatable column. The column has an external spiral groove in which rides a pin carried by, and extending into the bore of, a hub which fits around the column. Rotation of the column moves the hub up or down, depending upon the direction of rotation. The hub carries a plurality of arms equal in number to the number of stations, seven in the apparatus disclosed. Each arm has a magnet for attaching a novel film holder which is detachable at the unloading station. After loading a film holder with film to be processed, the holder is loaded into the machine through a spring-pressed loading door onto a loading platform which moves the film holder upwardly to engage it with one of the arms when the door is closed. Raising, rotation and lowering of the hub, arms and film holders is controlled by rotation of the column and proper arm positioning is assured by a novel escapement mechanism. The apparatus provides operation from loading to unloading with a minimum of human intervention, with high consistency of operation, and with treatment for equal time intervals in the developing, fixing, washing, liquid removal and spin drying stations.

1. Field of The Invention
This invention relates to photographic film developing apparatus of the type in which a film holder is moved in a circular path to a series of processing stations. The film holder is indexed from station to station and at the respective stations in lowered into and raised out of the station.
2. The Prior Art
It is known to develop photographic film in apparatus of the general type described above. See for example the following U.S. Pat. Nos.: 741,213, issued Oct. 13, 1903; 785,113, issued Mar. 21, 1905; 1,233,109, issued July 10, 1917; 2,544,644, issued Mar. 13, 1951; 2,723,610, issued Nov. 15, 1955; 2,975,695, issued Mar. 21, 1961; 3,010,377, issued Nov. 28, 1961; 3,412,667, issued Nov. 26, 1968; 3,722,384, issued Mar. 27, 1973; 4,011,573, issued Mar. 8, 1977; 4,410,257, issued Oct. 18, 1983; and 4,497,559, issued Feb. 5, 1985. These patents disclose various features of the general type of apparatus to which the present invention relates. They do not, however, disclose various distinguishing features of the invention, for example, the concept of achieving film holder agitation by reciprocation as carried out by the present invention, the structure by which the film holders are raised from and lowered into the respective stations and indexed to the next station, the novel loading station construction, the novel film holder structure, or the use of magnetic means to releasably attach the film holders to the structure which raises and lowers them and indexes them to successive stations.
These and other features of the invention provide a novel and highly efficient processing apparatus which can operate with a minimum of human intervention, and which operates reliably without the enormous complications found in the prior art use of numerous cams, pulleys, chains and the like.


A database federation mechanism permits one or more applications external to the database to be registered. Applications so registered may be automatically invoked in response to database queries—where such invocation utilizes data from specific database entries.

A Configuration Management Database (CMDB) is a database that is used to retain information about the components in an information system (and the relationships between those components) that are used by an organization's Information Technology (IT) services. In this context, system components are often referred to as "configuration items." A configuration item can be any conceivable resource or component, including software, hardware, documentation, facilities and personnel, as well as any combination of these. The process of configuration management seeks to specify, control, and track configuration items and any changes made to them in a comprehensive and systematic fashion.
The Information Technology Infrastructure Library (ITIL®) best practices standards include specifications for configuration management. According to ITIL specifications, the four major tasks of configuration management are: (1) identification of configuration items to be included in the CMDB; (2) control of data to ensure that it can only be changed by authorized individuals; (3) status maintenance, which involves ensuring that the current status of any configuration item is consistently recorded and kept updated; and (4) verification, through audits and reviews of the data to ensure that it is accurate. (ITIL is a registered trademark of The Lords Commissioners of Her Majesty's Treasury Acting Through The Office of Government Commerce and Central Computer and Telecomunications Agency, United Kingdom.)
Within a configuration database, the concept of data federation is an important scalability and complexity management issue. Generally speaking, data federation is the concept of storing additional or related data about a configuration item (stored in a first data store) in another, second, product or database. This approach to distributing data keeps the size, scope and responsibility of the configuration database controlled and allows the use of existing databases as they currently exist.
In the prior art, federated data is generally accessed by manually executing an application distinct from the federated database. For example, federated data may be retained in a second database (accessible through a separate database management system) or a distinct product (such as a separate configuration management application). Data federated in this manner may be accessed by developing customized source integration logic or by invoking a pre-determined or fixed instance of a second application. In the first of these approaches, custom logic (i.e., software) is developed for each federated database that allows a more automated interaction with the specified data store. In the second approach, the second application is used to manually search for the desired data. In yet a third approach, links to an application that could manipulate an instance of a federated data object are provided, but no ability to modify the invocation of this link (including parameter passing) is possible.
Thus, it would be beneficial to provide a mechanism to automatically and dynamically invoke a specified application from within a database in general, and a configuration management database in particular.


Systems and methods for providing estimated wait times are provided. More particularly, an estimated wait time is calculated based at least in part on agent availability information entered by the agent. The agent availability information may be obtained from the agent through a user interface provided by a contact center communication device. The user interface may include soft keys. In addition, the estimated wait time can be provided to client communication devices.

Call centers are systems that enable agents to serve incoming and/or outgoing calls, with the calls being distributed and connected to whichever of the agents is available to handle the call. When no agents are free and available to handle an incoming call, additional incoming calls are typically placed in a holding queue to await an available agent. It is common practice to divide a pool of agents into a plurality of groups, commonly referred to as splits, and to assign different types of calls to different splits. The different splits may be organized such that they are directed to servicing particular products or offerings, and the agents in different splits may have different skills. Each split typically has its own incoming call queue. In addition, agents may be distributed across a number of call centers.
In a typical inbound contact center arrangement, customer service representatives handle a variety of incoming calls. For each new call that a call center receives, decisions can be made by call routing algorithms as to whether a call should be assigned to an available agent or held in a queue for an agent more likely to have the skills required to handle the call. For an outbound contact center, the decision of when to place a predictive dialing call can be based on the expected remaining work time of all agents that might be able to handle the call about to be placed.
One of the inputs to call routing algorithms can be the expected remaining work time of each agent. Typically, this estimate is based on the average call time. Moreover, the average call time can be computed separately for different types of calls, in order to improve the accuracy of the estimate. Expected wait time can be calculated by calculating the average call holding time for all calls of a particular class, and then subtracting the time an agent has spent on the call up to the point at which the estimate is made. However, the estimated remaining work time for a particular call being handled by an agent is only a general estimate, and does not take into account the current pace of the call in progress with that agent. Accordingly, estimated wait time announcements, which are played to callers waiting in queue, can be inaccurate. For example, current solutions do not consider whether an agent is intending to enter an auxiliary mode or otherwise break from handling calls when a current call is finished, and do not consider particular issues that may be raised during a call in progress.

Playing expected wait time on agent's notification


An apparatus for dilution of discharged fuel of a fuel cell is provided, which has an inlet for guiding purged hydrogen gas coming from the fuel cell, a reservoir for storing the purged hydrogen gas guided through the inlet, and a cathode exhaust gas pipe penetrating the reservoir. The cathode exhaust gas pipe has a feature that it has holes inside the reservoir and is supplied with cathode exhaust gas of the fuel cell. Also the apparatus has a feature that the cathode exhaust gas pipe sucks the purged hydrogen gas stored in the reservoir through the holes and discharges the purged hydrogen gas diluted by mixing with the cathode exhaust gas.

In a fuel cell system serving as a power source for an electric vehicle, which employs pure hydrogen gas (hereinafter referred to as hydrogen gas) for example, a circulation system for supplying the hydrogen gas has been selected so as to improve the fuel efficiency. Japanese Published Patent Application 6-275300 reports one example of this system. As a circulation method, an ejector which sucks hydrogen gas by negative pressure or a vacuum pump has been adopted.
Continuation of recirculation for hours in a circulation system sometimes causes a rise in the concentration of impurities in hydrogen gas such as nitrogen, thereby downgrading the efficiency of power generation. Also accumulation of water sometimes lowers the flow of hydrogen gas in an anode line of a fuel cell system. It is therefore necessary to conduct purging operation so as to discharge impurities such as nitrogen and water. It should be noted that the hydrogen gas of high concentration is discharged inevitably from the anode line filled with hydrogen gas during purging operation. This has posed a problem of safe hazard that the purged hydrogen gas is discharged directly into the open air.
In this connection, Japanese Published Patent Application 6-275300 does not disclose an idea that purged hydrogen gas should be discharged into the open air after undergoing a dilution process.

Apparatus for dilution of discharged fuel