Abstract:
A wireless vibrometer employs an antenna array to significantly boost the signal-to-noise ratio of faint received signals twin small objects vibrating at acoustic frequencies. This technique may be used to provide an improved physiological monitor (such as a pulse detector) or for long-range eavesdropping using the emitted power from a cell phone or the like.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    This invention was made with government support under CNS 1318292, CNS134,3363, CNS1350039, and CNS1404613 awarded by the National Science Foundation. The government has certain rights in the invention. 
     
    
     CROSS REFERENCE TO RELATED APPLICATION 
     Background of the Invention 
       [0002]    The present invention relates to methods of measuring acoustic signals, such as those produced by a person&#39;s pulse or voice, by using wireless signals, and in particular to a system using an antenna array for practical vibrometry in situations with small vibrating targets and/or weak signals. 
         [0003]    Devices such as wrist mounted fitness monitors may monitor pulse by measuring changes in reflected light caused by blood flow (photoplethysmograhy). In each cardiac cycle, a pressure pulse distends the arteries slightly increasing reflective area of the blood. Accurate readings using photoplethysmograhy often requires repositioning the measuring device from the wrist to the forearm and securing it tightly about the forearm. Cold weather, tattoos, and irregular movements of the arm may interfere with measurements. Recently there has been some concern that photoplethysmography techniques can be inaccurate at high intensity workout levels. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides a wireless vibrometer using an array of transmitters and receivers that may isolate and detect faint vibrations, for example, from an arterial wall during the cardiac cycle or from surfaces vibrating in response to speech. 
         [0005]    In a fitness monitor, the array maybe directed inwardly from a wrist strap toward an artery and by isolating vibration of the artery walls may effectively measure pulse without interference from other physiological, movements and/or variations in the placement and contact of the array. 
         [0006]    More generally the invention provides extremely sensitive measurement of the vibration of structures providing only weak reflections allowing a range of new applications of wireless vibrometry. 
         [0007]    Specifically, in one embodiment, the invention provides a wireless vibrometer having an antenna array having antennas distributed over at least one dimension. A transmitter connectable to given antennas of the array shifts at least one of a relative phase and amplitude of a transmitter radiofrequency signal transmitted from each given antenna according, to a transmission weight associated with each given antenna. A receiver connectable to given antennas of the array, shills of at least one of a relative phase and amplitude of a reflection of the radiofrequency signal received from each given antenna according to a reception weight associated with each given antenna before, combining the reflection radiofrequency signals to a received signal. An electronic computer executes a program stored in a non-transitive medium to: (a) extract an audio signal from the received signal; (b) evaluate the audio signal to adjust the transmission weights and reception weights to provide a processed audio signal with improved signal-to-noise ratio; and (c) output, a measure of the processed audio signal. 
         [0008]    It is thus a feature of at least one embodiment of the invention to provide improved measurement of small vibrating surfaces producing weak radiofrequency signals. 
         [0009]    The vibrometer may include a housing for supporting the antenna array adjacent to a person&#39;s skin to direct transmitted radiofrequency signals into the skin and to receive reflection radio signals reflected out of the skin. 
         [0010]    It is thus a feature of at least one embodiment of the invention to provide a physiological monitor overcoming the problems of, or supplementing, photoplethysmograhy. 
         [0011]    The housing may provide an adjustable band for passing around the limb of a human to retain the housing against the 
         [0012]    It is thus a feature of at least one embodiment of the invention to provide a physiological monitor operable in the convenient form factor of an arm or wristband. 
         [0013]    The electronic computer may extract a dominant frequency of the processed audio signal within a pulse rate range of the human heart and the measure of the processed audio signal is a pulse rate. 
         [0014]    It is thus a feature of at least one embodiment of the invention to provide an improved pulse monitor. 
         [0015]    The array may provide antennas dispersed in two dimensions. 
         [0016]    It is thus a feature of at least one embodiment of the invention to permit a two-dimensional optimization of a synthesized measurement axis that can work with vibrating surfaces in a variety of orientations. 
         [0017]    The antenna array may extend over an area of less than 2.5 square inches. 
         [0018]    It is thus a feature of at least one embodiment of the invention to provide a compact wireless vibrometer suitable for portable devices. 
         [0019]    The electronic computer may select the transmission weights and the reception weights by cycling through a limited set of discrete transmission weights and reception weights to select transmission weights and reception weights according to a maximization of the audio range of the received signal provided by the selected transmission weights and reception weights. 
         [0020]    It is thus a feature of at least one embodiment of the invention to provide a method of beamforming when there is no a priori identified target. 
         [0021]    The limited set of discrete transmission, weights and reception weights may provide for a range of amplitude weighting of no less than 2 to 1 in no more than 100 weights and/or a limited set of discrete transmission weights and reception weights to provide for a range of phase weighting of no less than 180 degrees in no more than 100 steps. 
         [0022]    It is thus a feature of at least, one embodiment of the invention to employ a limited search space for tractable beamforming in this application. 
         [0023]    The electronic computer may (I) transmit a radio signal from an antenna while cycling through a limited set of discrete transmission weights to select first transmission weights according to a maximization of the audio range of the received signal and then (ii) use the first transmission weights as reception weights while cycling through the limited set of discrete transmission weights to select second transmission weights according to a maximization of a measure of the audio signal of the received signal. 
         [0024]    It is thus a feature of at least one embodiment of the invention to rapidly identify a dominant source for vibrometry. 
         [0025]    The electronic computer may further control a frequency of the transmitter and receiver and cycles through a discrete set of transmission frequencies to select ,a transmission frequency for obtaining the extracted audio signal according to a maximization of a measure of the audio signal of the received signal. 
         [0026]    It is thus a feature of at least one embodiment of the invention to provide improved sensitivity to faint vibrations through transmission frequency adjustment such as may accentuate radio signal interference effects. 
         [0027]    In one embodiment, the invention may provide a system for eavesdropping on audio data, the system comprising a wireless transmitter (such as a cell phone) providing a microphone for receiving audio data and a transmitter for transmitting the audio data in an encrypted radio signal and a wireless vibrometer. The wireless vibrometer may include an antenna array having, antennas distributed over at least one dimension and a receiver connectable to given antennas of the array, the receiver receiving the encrypted radio signal at each given antenna and shilling at least one of a relative phase and amplitude of the reflection radiofrequency signal according to a reception weight associated with each given antenna before combining the reflection radiofrequency signals to a received signal. An electronic computer executes a program stored in a non-transitive medium to: (a) measure variations in electrical power of the encrypted radio signal over time; (b) extract an audio signal from the variations in electrical power; (c) measure the audio signal to adjust the transmission weights and reception weights to provide a processed audio signal with improved signal-to-noise ratio; and (c) output the processed audio signal. 
         [0028]    It is thus a feature of at least one embodiment of the invention to provide a method of eavesdropping on encrypted radio transmissions by monitoring the vibration of the transmitter elements before signals from those vibrations have become encrypted. 
         [0029]    In one embodiment, the invention provides a wireless transmitter hardened against eavesdropping and including (1) a microphone for receiving an audio signal to provide electrical audio data, (2) a transmitter for receiving electrical audio data, and (3) a power control signal, and transmitting the audio data in encrypted form at a power determined by the power control signal. An audio noise source provides an audio signal in the bandwidth of a human voice and communicates with the transmitter to provide at least a portion of the power control signal to the transmitter. The audio noise source provides a variation in transmitting power comparable to that produced without the audio noise source as a result of vibration of portions of the wireless transmitter under the influence of an audio signal. 
         [0030]    It is thus a feature of at least one embodiment of the invention to produce a transmitter hardened against eavesdropping through monitoring of power variations caused by vibration of the elements of the transmitter. 
         [0031]    These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0032]      FIG. 1  is a perspective view of one embodiment of the invention directed to a wrist mounted physiological monitor held by a wristband and showing in an enlarged fragmentary phantom view, and antenna array such as may be held in position directed upward against the bottom of the wrist by the wristband; 
           [0033]      FIG. 2  is a block diagram of the electrical components of the embodiment of  FIG. 1  showing circuitry for switching weighted transmission and reception signals between antennas of the array of  FIG. 1  through the use of an electronic computer; 
           [0034]      FIG. 3  is a signal processing diagram showing processing of a composite received radiofrequency signal to extract audio data; 
           [0035]      FIGS. 4 a -4 c    are simplified views of the antenna array of  FIG. 2  showing steps in establishing the weighted values of the transmission and reception signals; 
           [0036]      FIG. 5  is a flowchart of a program executed by the computer  FIG. 2  in implementing the weight-determining steps of  FIG. 4 ; 
           [0037]      FIG. 6  is a perspective view and block diagram of the principal components of a handheld radio transmitter such as a cell ph one showing phase/amplitude modulation caused by vibration of the phone and/or its components; 
           [0038]      FIG. 7  is a diagram of a processing step that may be implemented by the processor of  FIG. 2  to measure variations in transmitted power level in packets transmitted by the transmitter of  FIG. 6  to extract audio data; 
           [0039]      FIG. 8  is a framentary view of the transmitter of  FIG. 6  including additional components to prevent eavesdropping through the use of the technique of  FIG. 7 ; and 
           [0040]      FIG. 9  is a figure showing an alternative embodiment of placement of the antenna array of  FIG. 1  for augmenting vocal communications in noisy environments. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Sensitive Vibrometry 
       [0041]    Referring now to  FIG. 1 , in one embodiment, the invention may provide for a wristband  10  that may be placed about the wrist  12  or upper forearm of a person to monitor physiological signals manifest as vibration. Such signals may include cardiac pulse, respiration, hypovolemia and the like. 
         [0042]    The wristband  10  may include a band portion  14 , for example, constructed of an elastic material or including a hasp for tightening the band about the wrist  12 . As so positioned, the band portion  14  may support housing  16  pressing upward, for example, against the underside of the wrist. The housing  16  may be substantially rigid and support an internal antenna array  18  of independent antennas  20 . The antennas  20 , for example, may be arranged in rows and columns in two dimensions, for example, limited to an area of approximately 2.5 inches or less so that the entire antenna array  18  may fit adjacent to the wrist. 
         [0043]    The antennas  20  are located and constructed so as to direct or receive radiofrequency signals along primary lobe axes  22  directed to intersect the wrist  12  in a direction generally perpendicular to a plane of the array  18  over which the antennas  20  are dispersed. 
         [0044]    Referring now to  FIG. 2 , the antennas  20  can be divided into separate groups  24   a  and  24   b,  either of which may be used for transmission and reception as will be discussed. The groups  24   a  and  24   b  will generally include interspersed antennas  20  to provide maximum spatial separation among antennas  20  in each antenna group  24 . 
         [0045]    Antennas  20  in each antenna group  24   a  and  24   b  may be connected either to a transmitter  26  or a receiver  28  and this connection may be switched by means of multiplexers  30   a  and  30   b  under the control of a computer  32  as will be discussed. 
         [0046]    Transmitter  26  provides a set of output signals  33  based on a common transmission signal  35  but independently shifted in at least one of phase and amplitude with respect to that common transmission signal  35  according to transmission weights  34 . The values of the transmission weights  34  may be controlled by the computer  32  and will be determined by a process described below. Each of these separately shifted output signals  33  is provided to a corresponding different antenna  20  in the antenna group  24   a  or  24   b,  whichever is associated with the transmitter  26 . 
         [0047]    In a similar manner, receiver  28  may receive a set of input signals  36  from antennas  20  of a selected one of antenna group  24   a  and  24   b.  These input signals  36  may then be independently shifted in at least one of phase and amplitude according to reception weights  38  (also controlled by the computer  32  as will be discussed). The shifted input signals  36  may then be combined to produce a received radio signal  40 . 
         [0048]    In one embodiment, the transmitter  26  and receiver  28  may operate in at a set of frequencies within a range falling within a broader range of 300 megahertz to 64 gigahertz, although the invention in some embodiments need not be limited to this frequency range. 
         [0049]    The common transmission signal  35  may be generated by the computer  32 , and as noted above, the computer  32  may control the transmission weights  34  (for example, describing a frequency and amplitude or a spectral content). In addition, the computer  32  may receive a combined radio signal  40 , for example, after basic demodulation and downshifting or directly as sample data by a high-speed analog-to-digital converter and as noted above may control the reception weights  38 . 
         [0050]    The computer  32 , as is generally understood in the art, may include one or more processors  42  executing a stored program  44  held in computer memory  46 . The computer  32  may communicate with a secondary transmitter  50 , for example, a Bluetooth transmitter, for communicating data to a cell phone or the like, and to a display  52  and user controls  54  such as pushbuttons and the like to provide an interface to a user, for example, for receiving commands and displaying output value such as pulse rate and the like. 
         [0051]    Each of the circuit elements described above may be contained within the housing  16  and may he powered by means of a self-contained battery  56  as is generally understood in the art. 
         [0052]    Referring now to  FIG. 3 , generally the program  44  will control the computer  32  and through the computer  32  control the other components connected to the computer  32  in order to transmit a signal  62  from the antennas  20  being the signal  33  transmitted from each of the antennas  20 . Similarly, the computer  32  may receive signal  40  from the antennas  20  as combined by the receiver  28  being a signal reflected from tissue  66  such as an arterial wall in the wrist  12 . 
         [0053]    The receive signal  40  may be sampled and converted to digital values by an A/D converter  70  at a high sampling rate well above the Nyquist sampling rate needed for the audio upper range of the vibration of interest. For a pulse rate of 0.5 hertz to 2.5 hertz, the sampling rate will be in excess of 1 megahertz, well above the Nyquist sampling rate of five hertz. As will be discussed later, when the invention is used for decoding human speech, the range of vibration of interest may be, for example, in a range of 80-500 hertz. For human speech, therefore, the sampling rate is still well above the Nyquist sampling rate necessary to sample human speech. 
         [0054]    Excess sampling by the A/D converter  70  may allow averaging or other combinations of adjacent samples to provide a lower sample rate signal  72  having improved noise qualities. 
         [0055]    Signal  72  may then be transformed, for example, by a fast Fourier transform  74  implemented in software or hardware to provide a dynamic frequency domain signal including amplitude signal  76  and phase signal  77  as is generally understood in the art. The amplitude signal  76  and phase signal  77  may be “windowed” to remove “DC” components and other values outside of the frequency range  78  being a frequency range of interest, for example, 0.5 hertz to 2.5 hertz for pulse rate or 80 hertz to 500 hertz for intelligible vocal communication. This windowed frequency domain signal may then be inverse transformed to provide an extracted or demodulated audio signal. Alternatively, and in the preferred embodiment, a peak amplitude component  80  of the amplitude signal  76  may be amplitude demodulated to produce an audio signal  82  and/or a peak component of the phase signal  83  corresponding to the peak amplitude component  80  and may be phase demodulated to produce audio signal  84 . Either of these signals  82  and  84  may be used individually or they may be combined as indicated by adder  90  to provide a measured audio signal  92 . 
         [0056]    For extracting pulse rate, this measured audio signal  92  may be further processed by a post-processor  94  according to the signal of interest. For example, for pulse rate, the post-processor  94  may provide a band pass filter and frequency counter that may output a pulse rate signal  96  that may be displayed on the display  52  in  FIG. 2  and/or transmitted on the transmitter  50  to a remote display. When the signal of interest is human speech, post-processor  94 , for example, may provide amplification gain control and the like and other intelligibility enhancing filtration steps generally understood in the art. 
         [0057]    Each of the components of the Fourier transform  74 , the adder  90 , and the post-processor  94  may be implemented in software or hardware according to techniques well known in the art. 
         [0058]    Referring now to  FIGS. 4 and 5 , the signal  40  processed as described above will normally be relatively weak because of the small reflection area of the tissue  66 . In addition, this week signal maybe corrupted by motion artifacts, for example, in the contact between the housing  16  and the skin and by movement of tendons and muscles around the tissue  66  of interest. Accordingly, the present invention may perform a “blind” beamforming to increase signal specificity with respect to the tissue  66 . 
         [0059]    Referring now to  FIGS. 2 and 4   a  and two process blocks  100  of  FIG. 5 , a first step in this beamforming process determines reception weights  38  by connecting the transmitter  26  to an arbitrary single antenna  20  of antenna group  24   b  and transmitting a carrier signal, for example, a constant frequency carrier signal having a frequency much higher than the bandwidth of the expected audio signal  92 . At the same time, receiver  28  is connected to antenna group  24   a  and each antenna  20  in antenna group  24   a  receives a signal which is processed by the receiver  28  using, corresponding reception weights  38 . 
         [0060]    These reception weights  38  may be, set initially to an arbitrary value (for example, 0 phase shifting, and an amplification factor of 1) and then the reception weights  38  are sequenced through discrete steps of one or both of amplitude and phase. For example, the reception weights  38  may range from 0.5 to 2 covering plus and minus 3 db of magnitude range in steps of 0.05. More generally, the reception weights  38  may have a range of amplitude weighting, of no less than 2 to 1 and the set of reception weights  38  may be less than 100 weight values for each reception weight  38 . Alternatively or in addition, the reception weights  38  may step through a range of phase shifts of 0-2π in steps of 0.1. More generally, the reception weights  38  may provide for phase weighting of no less than 180 degrees and the set of different weight values for each reception weight  38  is less than 100 steps. These same ranges and step numbers will also apply to sequencing through the transmission weights  34  as will be described below. 
         [0061]    The reception weights  38  are evaluated by extracting the audio signal  92  (shown with respect to  FIG. 3 ) and evaluating a signal-to-noise measure (such as peak signal-to-noise ratio). Generally the reception weights  38  are selected to maximize the signal-to-noise ratio measurement. 
         [0062]    Although, it is possible to search through all possible combinations of the discretized reception weights  38 , one embodiment of the invention employs a greedy algorithm in which each reception weight  38  is set in sequence, and the proper setting of the next reception weight  38  in the sequence is evaluated as to whether it improves the signal-to-noise ratio (for example, a peak signal-to-noise ratio) existing for the previously determined reception weights  38  without changing those previously determined reception weights  38 . 
         [0063]    Once reception weights  38  have been determined, these reception weights  38  are used as the transmission weights  34  for the same antennas  20  of antenna group  24   a  which is now connected to the transmitter  26  (switched from the receiver  28 ) as shown in  FIG. 4 b   . The transmitter  26  operating through antennas  20  of the antenna group  24   a  can be assumed to have provided beamforming to the location of the tissue  66  of interest based on the reciprocity in the behavior of constructive and destructive interference in both transmission and reception of radio signals. 
         [0064]    The common transmission signal  35  previously transmitted through one of antenna group  24   b  is now transmitted through each antenna  20  of antenna group  24   a  as subject to the transmission weights  34  as shown in  FIG. 4 b    and as indicated by process block  102  of  FIG. 5 . Reception weights  38  are again determined for the antennas  20  of antenna group  24   b  using the process described above with respect to determining reception weights  38 , again, to maximize the measure of signal-to-noise ratio received at the multiple antennas  20  of antenna group  24   b.    
         [0065]    Once this process is completed and as indicated by process block  104  of  FIG. 5  and  FIG. 4 c   , the antenna banks  24   a  and  24   b  are operated simultaneously (antenna group  24   a  receiving output from the transmitter  26  and antenna group  24   b  providing input to the receiver  28 ) using the derived transmission weights  34  and reception weights  38 . 
         [0066]    Using these derived transmission weights  34  and reception weights  38 , at optional step  108 , different frequencies are used for the carrier frequency to determine a frequency that maximizes the measure of signal-to-noise ratio used in the determination of the transmission weights  34  and reception weights  38 . 
         [0067]    As indicated by process block  110 , the identified transmission weights  34 , reception weights  38  and carrier frequency are then used to collect signal  40  for processing to extract an audio signal  92  and provide a measurement of that audio signal in signal  96 . 
         [0068]    Referring now to  FIGS. 1, 6 and 9 , the ability to extract audio signals from small vibrating reflectors per the present invention makes possible the use of the array  18  and the above described circuitry and processing as an auxiliary audio pick up, for example, for a cell phone  120 . In this embodiment, the array  18  may be incorporated into the cell phone  120  to direct a radiofrequency signal  62  (shown in  FIG. 3 ) toward a user&#39;s throat (for example) to extract a voice signal in the manner of a throat microphone. This voice signal may be used instead of or to augment, audio signals  134  received by a microphone  155  thus allowing the cell phone  120  to be better used in highly noisy environments. 
       Encryption Bypassing 
       [0069]    Referring to  FIG. 6 , the sensitivity provided by the present invention raises the possibility of eavesdropping on radio transmitters even when the transmitters encrypt the transmitted data. A typical radio transmitter such as a cell phone  120  may transmit a radio signal  122  containing encrypted data, for example, transmitted in a packet format with the data of each packet encrypted. 
         [0070]    As is generally understood in the art, the cell phone  120  may include a processor  124  communicating with a memory  126  holding a stored program  127 . The processor  124  may provide encrypted data signals  129  to a transceiver  128  for transmission as radio signals  122  through an antenna  130 . The processor  124  may also control the transmitter transmission power through a power control signal  131  to the transceiver  128 . 
         [0071]    The cell phone  120  may also include acoustically driven movable elements  132  such, as a speaker. Such elements are constructed to vibrate to provide audio output of received conversations. During this vibration, the movable element  132  will mechanically communicate vibrations to the antenna  130  to produce a phase shifted radio signal  122  emanating directly from the antenna  130 . The amount of phase shifting will depend on the instantaneous movement of the element  132  driven by the audio signal  134 . In addition, constructive and destructive interference between radio signal  122  and reflection signal  122 ′ in the environment will cause fluctuations in the power of a received composite of radio signal  122  and reflection signal  122 ′ that may be detected by the present invention. 
         [0072]    Referring now to  FIG. 7 , specifically, the composite radio signal  122  and reflection signal  122 ′ may provide for successive packets  140   a  and  140   b  each containing multiple symbols  142 , for example, in a pulse code modulated constellation. Standard circuitry on the transceiver  128  may extract the radiofrequency power represented by each symbol  142  as power signals  146 . The power signals  146  for corresponding symbols  142  of successive packets  140  are then compared to provide a corresponding set of power delta signals  150  that may accurately track constructive and destructive interference of the radio signal  122  and reflection signal  122 ′ as manifest in the changing amplitude of the combined signal which reveals motion of the movable elements  132 . The corresponding symbols  142  need not be in the same order in each packet  140   a  and  140   b  (as shown) but may be selected so that only identical symbols are compared. By comparing identical symbols, the high variation in power as a function of symbol is accommodated. 
         [0073]    To the extent that the packets  140  do not arrive at regular intervals, the delta signals  150  may be interpolated to regular sampling intervals. 
         [0074]    This delta signal  150  may then be processed in the same manner as signal  64  of  FIG. 3  using the blind beamforming steps  100 - 110  of  FIG. 5  to determine the appropriate transmission weights  34  and reception weights  38 . A potentially long range eavesdropping is provided because of the high signal strength of radio signal  122  compared to a reflected signal  122 ′ as provided in the example of  FIG. 3 . 
         [0075]    Referring now to  FIG. 8 , this possibility of eavesdropping may be decreased through modification of the cell phone  120  by introduction of a noise component into the power control signal  131  that masks amplitude changes caused by vibration of the movable element  132 . In particular, the power control signal  131  from the processor  124  may be summed to a noise source  152 , for example, the latter producing pseudorandom noise having a power spectrum concentrated in the band of human speech. A modified power control signal  131 ′ is then provided to the transceiver  128  to control the power level at which each packet  140  is transmitted. The resulting power fluctuations in the radio signal  122  serve to mask power fluctuation caused by the reflection signal  122 ′. 
         [0076]    This application incorporates by reference the paper: “Acoustic Eavesdropping through Wireless Vibrometry” by Teng Weiy, Shu Wangy, Anfu Zhou and Xinyu Zhangy MobiCom&#39;15, Sep. 7-11. 2015, Paris, France ACM 978-1-4503-3619-2/15/09. 
         [0077]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0078]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features, The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. it is also to be understood that additional or alternative steps may be employed. 
         [0079]    References to “a microprocessor” and “a processor” or “the microprocessor” and “the processor,” can be understood to include one or more microprocessors that can communicate in a stand-alone and/or a distributed environment(s), and can thus be configured to communicate via wired or wireless communications with other processors, where such one or more processor can be configured to operate on one or more processor-controlled devices that can be similar or different devices. Furthermore, references to memory, unless otherwise specified, can include one or more processor-readable and accessible memory elements and/or components that can be internal to the processor-controlled device, external to the processor-controlled device, and can be accessed via a wired or wireless network. 
         [0080]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications are hereby incorporated herein by reference in their entireties.