An acknowledgment paging system is described which fits within the existing infrastructure of a paging network and which provides low cost manufacture and low power operation while still enabling the acknowledgment paging over long distances. The acknowledgment paging system consists of a standard paging transmitter and a plurality of remote paging units which respond to a page using frequency-hopped spread-spectrum differential bi-phase shift keying communications. The plurality of pagers are assigned to groups with each group being assigned a separate starting location in a common, repeating pseudo-random noise code which determines the frequency hops. The grouping of pagers minimizes the collisions of acknowledgment transmissions between groups and the enables a large number of paging units to operate within a single geographic area.

Conventional one-way paging systems are well known in the art. Radio paging technology generally consists of simple tone pagers with a tone alert, a voice pagers with a voice message, numeric messages or an alphanumeric display pagers. In a typical paging system such as that shown in FIG. 1, a caller 10 places a call to a paging service provider at a paging terminal 12. The paging terminal queues up the messages to be sent to a number of remote paging units 14 via paging transmitter 13 which transmits a strong signal to the service area where all the remote pagers reside with enough power to reasonably reach all pagers within that market. Once the message is sent, there is no confirmation that it was ever received. The remote paging unit may be turned off, interference may have prevented reception, bad propagation conditions such as multipath, the unit may be out of the geographic service area, or any number of reasons may have prevented reception.
The messages transmitted from paging transmitter 13 to remote pager 14 generally use the POCSAG standard code for paging terminals. The POCSAG code includes a preamble, an address and a message for remote pager 14. The pagers within the geographic market area all receive the POCSAG codes on an assigned radio frequency and scan each message for the address assigned to the individual units. When the address (called a CAP code) is received, then the other information transmitted along with the code is recorded and displayed and the user is alerted.
In many markets, the single paging transmitter 13 is incapable of covering the entire geographic area of the local market. This may be due to the requirement of paging signal reception inside heavily constructed buildings, the fact that the antenna of a pocket receiver is inefficient and the proximity of the human body may affect field patterns for reception. In such cases, it is typical to find a paging communication system such as the system shown in FIG. 2. In this configuration, the caller calls through a PBX 15 through to the paging terminal 16 where the message is received and queued for transmission through VSAT 18 and uplink 19 to a geostationary satellite 20 for simultaneous retransmission (multicast) to a plurality of paging transmitter towers 13a,13b and 13c. In this fashion, an entire geographic market can be serviced with the simultaneous transmission of the same paging messages over all transmission towers 13a-13c. The use of a geostationary satellite of course is not the only method of simultaneous transmission to the plurality of paging towers. Terrestrial links may also be employed.
A block diagram of a typical pocket paging unit such as the type used with the configurations of FIGS. 1 and 2 is shown in FIG. 3. This configuration is well known to those skilled in the art and includes a receiving antenna 21 driving a crystal controlled receiver 22 which down converts the received signal and strips out the digital data using an identification detector 24 to locate the CAP code address in the POCSAG data. If the address matches the receiver's address, an audible alert may be sounded through speaker 29. The microcontroller 26 is available in alphanumeric pagers to display the information received on LCD display 27. Associated with controlling the operation of the pager are one or more push buttons 28. The power unit is included which essentially powers the entire pager with very small NiCd or alkaline batteries.
An essential feature of these types of pocket remote paging units is the ability to operate the receiving circuits at a very low power so that the user need not change the NiCd or alkaline batteries on a too-frequent basis. One of the essential marketing advantages of the use of pocket pagers is the low maintenance and reliability such that the user need not worry about frequent changing of the batteries.
A major drawback in the use of the paging system of FIG. 1 is the inability of the caller 10 to have any confidence that the holder of remote pocket pager 14 has received the message and is responding. In such critical industries such as the medical field, or for maintenance and repair personnel, it is essential that the caller know that the called party has received the message and is responding in a timely fashion. Unfortunately with the systems of FIG. 1, there is no such acknowledgement to give the caller any confidence.
To address this problem, a variety of acknowledgement paging systems have been proposed whereby the paging unit 14 has a means of acknowledging the receipt of the message and even informing the user of a menu of possible responses to the caller's query. Typical of these types of systems is the system described in U.S. Pat. No. 4,644,341 to Zabarsky et al. entitled "Two Way Personal Message System With Extended Coverage" which describes a relatively high power, wideband personal messaging system. This system is typical of early messaging systems which were inefficient both in power usage and bandwidth thereby restricting their use to a relatively narrow market. A later attempt to extend personal two way messaging to voice pagers is taught in U.S. Pat. No. 4,811,379 to Grandfield entitled "Speak Back Paging System".
To alleviate the bandwidth and power limitations, more sophisticated two-way messaging systems have been proposed. Typical of these types of systems is the system described in U.S. Pat. No. 4,825,193 to Siwiak et al. entitled "Acknowledge Back Pager with Adaptive Variable Transmitter Output Power". In the Siwiak patent, an acknowledgement paging system is described in which the remote paging unit has the ability to send one of a selected number of messages from a menu back to the paging terminal to acknowledge the receipt of the message. This system is further described in U.S. Pat. Nos. 4,823,123, 4,875,038 and 4,891,637 also to Siwiak et al. See also U.S. Pat. No. 5,142,279.
The system of the Siwiak patents transmits the acknowledgement signal on one of a list of frequency sub-bands approximately centered around 150 megahertz. The transmitting paging terminal sends the message to the acknowledgement pager of the Siwiak system and also tells it which frequency of the list of sub-band frequencies upon which the acknowledgement pagers should respond. In this fashion, the paging terminal reserves one of the sub-band frequencies for that particular acknowledgement message. By allocating and re-allocating the sub-band frequencies, collisions between simultaneous-transmitting multiple remote paging units is minimized.
There is a need in the art for the ability to conserve power in reverse pagers and the Siwiak system attempts to ameliorate this problem with limited success. The users of acknowledgement pagers demand the same performance and reliability of the acknowledgement pocket pagers as they do from the one-way pocket paging units. The problem with acknowledgement pagers, however, is the ability to transmit enough power from the pager so that the acknowledgement signal is received at the paging base terminal site. As was previously mentioned, the transmitting power from the paging base transmitter 13 is sufficiently strong to reach most if not all of the geographic market. If enough transmit power is unavailable to reach the entire geographic market, a plurality of transmit towers are used such as that shown in FIG. 2. Due to the large geographic markets typically found for paging systems, it is difficult to transmit enough power from a handheld or pocket-sized acknowledgement paging unit for that acknowledgement message to be received at the paging terminal. Thus, to generate enough power, either larger batteries are needed or more frequent changing of the batteries will result. The Siwiak patent includes a variable transmit power option which conserves battery power by transmitting allow power signal when the signal strength of the received signal from the transmit tower has a high signal strength. This would indicate that the transmit tower, and its associated receiving tower to receive the acknowledgement message, is reasonably close. If, however, the power level of the transmit signal from the paging transmitter 13 received by the acknowledgement pager is weak, that would indicate that a higher power transmit signal from the acknowledgement pager of the Siwiak invention would be needed and the transmit power is boosted. This of course shortens the battery life of the system. Even with a minimal amount of acknowledgements sent back to the transmitting site, the batteries do not last as long in acknowledgement pagers as in the traditional pagers.
Another concern in the area of acknowledgement paging is the ability to asynchronously transmit acknowledgment signals. The Siwiak patents described above suffer from the need to be tightly coupled to the base station in terms of assigned frequency use and time of transmissions of the acknowledgment signals to avoid message collisions between simultaneously transmitting pagers. An attempt at pseudo-asynchronous behavior is described in U.S. Pat. No. 4,868,560 to Oliwa et al. entitled "Voice Paging System Providing Deferred Paging Capability".
Another concern in the area of acknowledgement paging is the cost of the pager itself. The ability to conserve power so that batteries do not have to be replaced as often causes great constraints on the components used for the construction of such pagers. Once again, the market expects a certain level of cost for a pocket paging unit and acclimating that market to higher cost pagers will cause market resistance to the penetration of acknowledgement pagers. Thus, a concomitant goal would be to provide an acknowledgment pocket pager at approximately the same cost as the one-way pocket pager while having the ability to maintain approximately the same battery life.
Another problem with market acceptance of acknowledgement pagers is the ability to adapt an acknowledgement paging system to the existing infrastructure of a one-way paging network. As shown above, the ability to transmit enough power from a pocket pager to be received at the sites of the existing paging transmitter towers is directly at odds with the ability to conserve battery power so that the batteries do not have to be changed as often. This tradeoff has not been met by the paging schemes proposed to date and thus market acceptance of acknowledgement paging is inhibited.
Also, due to the limited bandwidth for transmitting acknowledgement signals and the need for a large number of two-way pagers in a single market, there is a need in the art for the ability to simultaneously transmit from pagers and receive the acknowledgment signals without interference from simultaneous transmissions. An attempt to address such a need is found in U.S. Pat. No. 4,882,579 to Siwiak entitled "Code Division Multiplexed Acknowledge Back Paging System". The system described in this patent attempts to address this problem by using direct sequence spread spectrum data transmission within single frequencies. This system is still quite limited in the number of non-colliding acknowledgment messages it can handle, it is rigid in the time and frequency of acknowledgment transmissions (entirely synchronous transmit and receive protocol) and is inefficient in its bandwidth usage.
There is also a need in the art for automatic handling of outgoing messages and return receipt of the acknowledgement messages. U.S. Pat. No. 5,153,582 to Jasinski et al. entitled "Method of and Apparatus for Acknowledging and Answering A Paging Signal" attempts to provide a semi-automatic means but a human operator is still required to receive the paging information.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a low-power, asynchronous reverse paging system adaptable to acknowledgement paging or polled response handling without collisions of simultaneous messages.

Grouping of spread spectrum acknowledgement pagers to minimize transmission collisions


Disclosed is a method for controlling connections between a terminal and one or more neighbor base station (BSs) by a serving BS with respect to the terminal. The method for controlling a configuration of connections between a terminal and one or more neighbor BSs includes: receiving, by the serving BS and from a control station, information regarding radio access technologies (RATs) which are supported and have been activated or deactivated by the one or more neighbor BSs from a control station; transmitting an activation request message from the serving BS to the control station in order to activate the radio access technology in the deactivated state if there is a need for activating the deactivated RAT to connect the terminal to the one or more neighbor BSs; receiving, by the serving BS and from the control station, an activation response message including information regarding the neighbor BSs and information regarding the at least one specific radio access technology which is activated according to the activation request message; and transmitting a connection request message from the serving BS to the terminal to allow the terminal to be connected to the one or more BSs according to the one or more activated radio access technologies using the at least one specific RAT.

2nd mobile communication refers to transmission and reception of voice through mobile communication, which includes CMDA, GSM, and the like. GPRS, advancing from the GSM, has been proposed to provide a packet switched data service based on the GSM system.
3rd generation mobile communication allows for transmission and reception of image and data, as well as voice, and 3GPP (Third Generation Partnership Project) has developed a mobile communication system (IMT-2000) technique and adopts WCDMA as a radio access technology (RAT). The combination of the IMT-2000 technique and the radio access technology (RAT), e.g., WCDMA, is called a UMTS (Universal Mobile Telecommunication System). UTRAN is an acronym of UMTS Terrestrial Radio Access Network.
3rd generation mobile communication is evolving to 4th mobile communication.
The 4th mobile communication technique includes a long-term evolution network (LTE) technique under standardization by 3GPP and an IEEE 802.16 technique under standardization by IEEE. The LTE uses a term of E-UTRAN (Evolved-UTRAN).
The 4th mobile communication technique has introduced OFDM (Orthogonal Frequency Division Multiplexing)/OFDMA (Orthogonal Frequency Division Multiple Access). OFDM uses a plurality of orthogonal subcarriers. OFDM uses orthogonality between IFFT (Inverse Fast Fourier Transform0 and FFT (Fast Fourier Transform). A transmitter performs IFFT on data and then transmits the same. A receiver performs FFT on received signal to restore the original data. The transmitter uses IFFT in order to combine a plurality of subcarriers and the receiver uses corresponding FFT in order to split the multiple subcarriers.
Meanwhile, in the 3rd and 4th mobile communication system, attempts for increasing cell capacity continue to support high capacity services such as multimedia contents, streaming, and the like, and bi-directional services.
In order to increase cell capacity, there has been an approach of using a high frequency band and reducing a cell radius. The use of a cell, such as a pico cell, or the like, having a small cell radius allows for the use of a higher frequency band than that used for the existing cellular system, having the advantages that more information can be delivered. However, because a larger number of base stations must be necessarily installed in the same area, much cost incurs.
Thus, recently, a femto cell has been proposed as one of approaches of increasing cell capacity by using small cells.
Femto cell refers to provision of a small-scale radio environment by installing a base station using small power in indoor spaces such as homes, offices, and the like. The femto cell is expected to improve an indoor service available area and increase capacity to thus enhance quality of service (QoS), and also expected to completely settle the next generation mobile communication system by providing data services.
For such a femto cell, standardization is ongoing in the name of Home eNodeB by 3GPP WCDMA and LTE group, and 3GPP2 is also actively studying femto cell.
Various structures as illustrated in FIGS. 1 and 2 have been proposed in order to implement such a femto cell in the existing mobile communication network.
First, FIG. 1 illustrates an example of a network structure based on femto cells according to the related art.
As shown in FIG. 1, a macro base station (M-BS) serving a wider area and a plurality of femto base stations (f-BSs) installed based on users.
The f-BSs are connected with a femto cell network controller (FNC) through the Internet so as to be under the control of the FNC, and provide services to users.
A terminal measures signals of neighboring cells and delivers the measured signal values to its f-BS, and the f-BS recognizes and administers the presence of neighboring cells based on the received signal values. Also, the f-BSs exchange information through a direct link or an indirect link through the FNC. The f-BSs and the M-BS transmit and receive information through the FNC, an RNC (Radio Network Controller) or through an MME (Mobility Management Entity) that controls the f-BSs in a mobile communication network.
FIG. 2 illustrates another example of a femto cell-based network structure according to the related art.
As shown in FIG. 2, f-BSs exchange information through a direct link or an MME, unlike the case illustrated in FIG. 1. Also, the M-BS and the f-BSs exchange through MMEs.
Meanwhile, recently, a service called FMC (Fixed Mobile Convergence) has been introduced. The FMC technique provides a cellular-based radio access technology (RAT), for example, a CDMA, TDMA, IMT-2000 (e.g., CDMA2000, W-CDMA), and LTE-based access scheme and a unlicensed frequency-based radio access technology (RAT) (e.g., Unlicensed Mobile Access, Bluetooth or Wi-Fi) to a terminal. To this end, the terminal must support a dual-mode.
Thus, when the dual-mode terminal comes close to a unlicensed frequency-based radio base station, the dual-mode terminal is allowed to use the same service as that in a cellular-based RAT through the unlicensed frequency-based RAT. For example, when the dual-mode terminal enters an area of a small radio base station using the unlicensed frequency-based RAT while it is communicating with the cellular mobile communication base station (i.e., the M-BS), it performs handover according to the unlicensed frequency-based RAT of the small radio base station to continue communication of high band seamlessly. In other words, as a terminal performs seamless handover between base stations, the dual-mode terminal is able to perform seamless handover between the cellular-based RAT and the unlicensed frequency-based RAT.
There have been attempts of applying such an FMC technique to a femto base station. Namely, among them is an attempt of combining the FMC communication technique along with cellular mobile communication to the femto base station.
FIG. 3 illustrates an example of combining the femto base station and the FMC technique.
As shown in FIG. 3, an M-BS 30 and an f-BS 20 are illustrated. The M-BS 30 is a general BS, but in this case, because the size of its cell radius is larger than the f-BS, the general BS is called the M-BS.
The f-BS 20 provides both a first RAT such as cellular communication and a second RAT based on an unlicensed frequency. Thus, when the terminal is located within the coverage of the f-BS 20, the terminal can be provided with a service through the unlicensed frequency-based RAT.
However, the related art does not provide a substantial procedure as to which of the first RAT such as the cellular communication or the second RAT such as unlicensed frequency based RAT provided by the target f-BS 20 the terminal 20 is to select when the terminal 10 enters the coverage of the target f-BS 20.
Thus, the related art terminal 10 preferentially selects the first RAT such as cellular communication provided by the target f-BS 20 for its accessing, which results in a failure of utilization of the FMC technique.
Also, if a femto BS supports multiple RATs, the femto BS could deactivate a specific RAT which is not used among the multiple RATs. In such situation, the terminal could not use the specific RAT to connect to the femto BS since the technique to allow the terminal to use the deactivated RAT is not provided.

Method for controlling connection configuration by femto base station and method for configuring connection by terminal


Techniques for providing voltage-controlled oscillator circuits having improved phase noise performance and lower power consumption. In an exemplary embodiment, a voltage controlled oscillator (VCO) is coupled to a mixer or a frequency divider such as a divide-by-two circuit. The VCO includes a transistor pair with magnetically cross-coupled inductors, and variable capacitance coupled to the gates of the transistor pair. In an exemplary embodiment, a frequency divider is configured to divide the frequency of the differential current flowing through the transistor pair to generate the LO output. In an alternative exemplary embodiment, a mixer is configured to mix the differential current flowing through the transistor pair with another signal. The VCO and mixer or frequency divider share common bias currents, thereby reducing power consumption. Various exemplary apparatuses and methods utilizing these techniques are disclosed.

In a communications transceiver for a wireless communications system, a local oscillator (LO) generates a signal with a predetermined frequency to be mixed with transmit and/or receive signals. An LO design may include a voltage-controlled oscillator (VCO) coupled to a frequency divider circuit used to divide down the frequency of the VCO output. The LO output may be coupled to a mixer that mixes the VCO output signal with another signal to generate a signal having an upconverted or downconverted frequency. A VCO buffer may be provided between the VCO output and the frequency divider or mixer to isolate the VCO output from subsequent loads.
There are often stringent requirements on the allowable in-band and out-of-band phase-noise generated at the LO output. For example, in the GSM and CDMA communication systems, the out-of-band phase noise requirement can be difficult to meet under a given power budget. The far-offset phase noise of the LO output is often dominated by contributions from the VCO buffer and the frequency divider. With proper circuit design, the VCO buffer may be eliminated; however, the frequency divider may still contribute significant phase noise. Reducing the phase noise of the frequency divider is typically achieved only by consuming a great deal of power. Similarly, the provision of a VCO and a mixer as separate circuit blocks may also consume significant power.
It would be desirable to reduce power consumption by integrating the functionality of the VCO with the frequency divider or mixer, while minimizing both near-offset and far-offset phase noise at the LO output.

Integrated voltage-controlled oscillator circuits


A quick connect fastener system is provided. In another aspect of the present invention, a snap-in fastener is used for retaining an automotive vehicle interior trim member. A further aspect of the present invention employs a base and a resilient retainer, one of which includes a metallic portion and the other of which includes a polymeric portion. Moreover, a generally rigid polymeric base employs a channel operably receiving a metallic retainer in a laterally sliding manner to ease in assembly of the retainer to the base in an adhesive and screw-free manner.

The present invention generally pertains to a fastener and more particularly to an interior trim fastener for an automotive vehicle.
Modular headliners and snap-in visor mounts are well known in the automotive industry. Such conventional constructions are disclosed in U.S. Pat. No. 5,201,564 entitled "Snap-In Visor Mount" which issued to Price on Apr. 13, 1993, and U.S. Pat. No. 5,082,323 entitled "Sunshade Fastener Module for Use with Modular Headliner" which issued to Dowd et al. on Jan. 21, 1992, both of which are incorporated by reference herein. The vehicle insertion forces, fastener retention and strength forces, and the suitability of the fastener to account for vehicular body variations, however, is not satisfactorily achieved with conventional devices.


This invention relates to methods and devices for time and frequency synchronization. The invention has particular application where time and frequency synchronization over packet networks using, for example, the IEEE 1588 Precision Time Protocol (PTP) is being carried out. The primary challenge in clock distribution over packet networks is the variable transit delays experienced by timing packets, packet delay variations (PDVs). Embodiments of the invention provide a method for time offset alignment with PDV compensation where a synchronized frequency signal is available at a slave device via Synchronous Ethernet and is used to determine the compensation parameters for the PDV.

There are many applications of high precision time synchronization over packet networks based on packet technologies like IP and Ethernet. Synchronization is a key requirement in telecommunication networks and the telecommunication industry has become a driving force in the development and evolution of synchronization solutions and standards. For example, wireless technologies like GSM, UMTS (both frequency division duplexing (FDD) and time division duplexing (TDD) versions of the UMTS technologies), and CDMA2000 require frequency accuracy of 0.05 ppm (parts per million) at the air interface.
In addition, CDMA2000 requires time synchronization at the ±3 μs level (±10 μs worst case) and UMTS TDD modes (i.e., TD-CDMA and TD-SCDMA) require accuracy off 1.25 μs between base stations. The accurate reference clock is typically derived from Time Division Multiplexing (TDM) interfaces (for GSM, UMTS-FDD (i.e., W-CDMA) and other FDD based technologies) or from expensive GPS receivers located at the base station (for TDD based technologies). In reality, TDD base stations today use GPS and wireless operators have long sought alternative synchronization sources.
Without synchronization traceable to a highly accurate reference clock in the wireless network, local interference between channel frequencies, as well as mutual interference with neighboring base stations will occur. This could ultimately cause calls to be dropped and a degradation of the overall user experience. The high level of synchronization provided by IEEE 1588 PTP could also be useful in time-of-arrival (TOA) and time-difference-of-arrival (TDOA) based localization solutions where one is interested in locating mobile nodes connected to a wireless network.
IEEE 1588 PTP has been designed as an improvement to current methods of synchronization within a distributed network of devices connected to a packet network. It is designed for systems requiring very high accuracies beyond those attainable using Network Time Protocol (NTP). Unlike NTP, IEEE 1588 uses hardware timestamping to deliver timing accuracy well under a microsecond (nanosecond level accuracies). It is also designed for applications that cannot bear the cost of a GPS receiver at each node, or for which GPS signals are inaccessible.
IEEE 1588 PTP can be used for distributing timing information (frequency and time) from a master to one or more slaves. The clock recovery mechanism at a slave will normally have to correct for both frequency and time deviations from the master clock during clock recovery.
Synchronous Ethernet (Sync-E), defined in a suite of ITU-T Recommendations, describes a method for frequency (only) distribution over the physical layer of Ethernet (IEEE 802.3). Since time synchronization requires both frequency and time offset alignment between master and slave clocks, some solutions suggest the combine use of Sync-E and IEEE 1588 PTP where Sync-E provides frequency alignment while IEEE 1588 PTP provides time offset correction.
In this setup of hybrid Sync-E and IEEE 1588 PTP, Sync-E provides perfectly a frequency synchronization signal using Ethernet physical layer frequency transfer, while IEEE 1588 PTP provides time synchronization over the packet network (above the physical layer). With frequency synchronization provided, the only issue here is determining the time offset between slave and master clocks. The time offset should be fixed (a constant) since slave's frequency is aligned to the master's. However, even for time offset determination, the problem here is that IEEE 1588 PTP messages are still exposed to the PDVs inherent in the packet network even though frequency synchronization is available through Sync-E. This is particularly the case if PTP messages are sent end-to-end from master to slave with the intermediate packet network providing no assistance whatsoever (like hop-by-hop Boundary Clocks or Transparent Clocks) to mitigate and compensate for PDV.
PDV therefore still makes time synchronization a challenge even though the frequency synchronization aspect is solved.
A complete IEEE 1588-based solution includes clock recovery (control) algorithms, filters, and PTP-clock based on hardware timer and direct timer access. The IEEE 1588 standards define a wide range of synchronization capabilities except the clock recovery mechanisms (servo algorithm, phase-locked loop (PLL), timers, etc.) to be used at the receiver (slave) to synchronize its local clock to the master. The last pieces are vendor and proprietary solutions and are often product differentiators.
Effects of Packet Delay Variations on Clock Synchronization
PDV is the main factor affecting the accuracy and stability of slave clocks when using packet timing protocols such as IEEE 1588 PTP. Packet network devices such as switches and routers introduce a variable delay to packets (PDV) that inhibits accurate path delay measurements and clock synchronization. Even for techniques that do not require path delay measurements for clock (e.g., frequency) synchronization, the PDV is a direct contributor to the noise in the recovered clock. The PDV inherent in packet networks is a primary source of clock noise. The higher the clock noise, the poorer the clock quality rendering the recovered clock sometimes unusable for end system applications when the noise exceeds application defined thresholds. (The term clock noise here refers to all impairments to the timing information recovered at the slave including jitter, wander, and other imperfections in the recovered clock.)
For instance, for time synchronization, the variation in delay from packet to packet through the network induces noise in the slave's perception of the time at the master. Constant delay (assuming frequency synchronized clocks) would cause a fixed offset, however variable delay causes a varying estimate of the offset. The performance of the slave is affected by both the magnitude of this variation, and how effective the slave's filter is at removing this noise.
Synchronous Ethernet
Clock synchronization methods fall under two broad categories, namely: Layer 1 methods, and Layer 2 and higher methods (Layer 2+) of the OSI model of communication. A schematic of the Layer 1 methods is shown in FIG. 1. A schematic of the Layer 2+ methods is shown in FIG. 2.
The Layer 1 (e.g., Sync-E, PDH, SONET/SDH), and Layer 2+ methods (e.g., NTP, IEEE 1588 PTP) differ mainly in the method used to inject and transport synchronization over the network 2 from a reference clock 1. Layer 1 methods achieve synchronization via the physical layer 4a, 4b bit stream while the Layer 2+ methods do so using higher levels 5a, 5b above the physical layer, for example, via differential clocking mechanisms, processing transmitted clock samples (timestamps) encoded within the packets from a transmitter to a receiver, or processing packet arrival patterns at the receiver to generate timing signals. Layer 1 methods generally support frequency transfer only while Layer 2+ methods support both frequency and time transfer.
ITU-T Recommendations G.8261, G.8262, G.8264 (which define Sync-E) indicate that synchronization can be achieved over Ethernet links by synchronizing the bit clock of the physical layer as is currently done on SONET/SDH links. The clock distribution aspect of Sync-E is essentially native Ethernet equipped with point-to-point distribution of timing signals. By enabling point-to-point distribution of timing signals from an accurate timing reference source, Sync-E aims to bring carrier grade telecom quality clocks to packet networks. Sync-E, unlike IEEE 1588, cannot deliver absolute time (i.e., time-of-day, wall-clock); Sync-E provides frequency distribution only.
The most significant aspect of native Ethernet communications is that the transmitter and receiver clocks are independent (free-running with frequency accuracy not exceeding ±100 parts per million (ppm)) as shown in FIG. 3 and are not synchronized as in TDM networks. In fact, there need be no strict timing relationship between successive frames as individual frames are separated by an idle period or at a minimum an inter-packet gap (IPG). The Ethernet transmitter delimits each packet by a start sequence ("preamble") and a stop sequence ("start-of-idle" or "end-of-stream delimiter"). At the receiver, a clock of the same nominal frequency is recovered and used to clock-in the data to a receive shift register. Only data that are bounded by the correct start and stop bit patterns are accepted.
Sync-E implements timing similar to what is seen in traditional TDM networks (e.g., PDH, SONET/SDH): the physical layer of an Ethernet link is used to deliver timing from one end of the link to the other. Timing transfer is achieved by enslaving the downstream link's Ethernet physical layer clock to the upstream clock. FIG. 4 shows the transmission of frequency from a master 10 to a slave 20. Synchronization is achieved through the use of a digital phase-locked loop (PLL) 6a, 6b in each of the master and slave. The PLL cleans (improves) the incoming clock signal in the slave 20 to filter out jitter and wander and in turn generates the necessary output clock(s), telecom and/or Ethernet clocks, for the receiving interfaces and devices.
FIG. 5 shows the way in which timing transfer is achieved across a sequence of Ethernet nodes 30a-c (although 3 nodes are shown in FIG. 5, it will be appreciated that this configuration can be extended to cover significantly larger networks). Each node has its own crystal oscillator 31 which drives a local clock. The local clock is synchronized to the reference frequency 1 by timing transfer over the physical layer 4 components and the clock signals recovered using the PLL 6a-c as described above. Effectively each node acts as a slave to its neighbour node in the "upstream" direction of the node 30a having the frequency reference 1 and as a master to its neighbour node(s) in the "downstream" direction.
The obvious advantage of this approach is that, by relying on the physical layer only, clock synchronization quality is not influenced by impairments introduced by the upper layers, namely, packet delay variation (PDV), packet losses, and out-of-order arrival of packets at their destinations.
The 10 Mb/s version of Ethernet cannot support Sync-E. In fact, the 10 Mb/s Ethernet (10BASE-T) is not even capable of synchronization signal transmission over the physical layer interface because a 10BASE-T transmitter stops sending pulses during idle periods. A 10BASE-T transmitter simply sends a single pulse, keepalive pulse, every 16 ms to notify its presence to the receiving end. Of course, such infrequent pulses are not sufficient for clock recovery at the receiver. Idle periods in faster Ethernet flavors (100 Mb/s, 1 Gb/s and 10 Gb/s) are continuously filed with pulse transitions, allowing continuous high-quality clock recovery at the receiver and are therefore good candidates for Sync-E.
IEEE 1588 PTP
IEEE 1588 is now the industry accepted packet-based method/standard for synchronization of clocks in distributed systems with accuracies in the nanosecond levels. PTP can be used for both time and frequency synchronization, unlike Sync-E which allows for only frequency synchronization. PTP is a message based protocol that can be implemented across packet based networks including, but not limited to, Ethernet. Its underlying principle is a master/slave concept based on the regular exchange of synchronization messages. IEEE 1588 synchronizes all clocks within a network by allowing clocks to adjust their frequency/time to the highest quality clock (the GrandMaster clock).
IEEE 1588 PTP allows for two different types of timestamping methods, either one-step or two-step. One-step clocks update time information within event messages (Sync and Delay_Req) on-the-fly, while two-step clocks convey the precise timestamps of packets in general messages (Follow_Up and Delay_Resp).
A Sync message is transmitted by a master to its slaves and either contains the exact time of its transmission or is followed by a Follow_Up message containing this time. In a two-step ordinary or boundary clock, the Follow_Up message communicates the value of the departure timestamp for a particular Sync message. A Delay_Req message is a request for the receiving node to return the time at which the Delay_Req message was received, using a Delay_Resp message.
The message exchange pattern for the two-step clock can be explained as follows and is illustrated in FIG. 6. The master 101 sends a Sync message to the slave 103 over the packet network 102 and notes the time T1 at which it was sent. The slave 103 receives the Sync message and notes the time of reception T2. The master 101 conveys to the slave the timestamp T1 by one of two ways: 1) Embedding the timestamp T1 in the Sync message (a one-step clock—not illustrated). This requires some sort of hardware processing (i.e., hardware timestamping) for highest accuracy and precision. 2) Embedding the timestamp T1 in a Follow_Up message (the two-step clock as shown in FIG. 6). Next, the slave 103 sends a Delay_Req message to the master 101 and notes the time T3 at which it was sent. The master 101 receives the Delay_Req message and notes the time of reception T4. The master 101 conveys to the slave 103 the timestamp T4 by embedding it in a Delay_Resp message.
At the end of this PTP message exchange, the slave 103 possesses all four timestamps {T1, T2, T3, T4}. These timestamps may be used to compute the offset of the slave's clock 105 with respect to the clock reference 104 in the master 101 and the mean propagation time of messages between the two clocks. The computation of offset and propagation time assumes that the master-to-slave and slave-to-master propagation times are equal—symmetrical communication path.
The present invention aims to provide a method for time offset alignment with IEEE 1588 PTP with PDV compensation.

Khalifa University of Science, Technology, and Research


Copolymerizable benzophenone photoinitiators of the formula I ##STR1## wherein 1, k=0, 1, 2.. R.sub.1 =divalent organic group having 1 to 25 carbon atoms; PA1 R.sub.2 =H or methyl; and PA1 R.sub.3, R.sub.4 =organic group having 1 to 25 carbon atoms. PA1 X, Y=hydrogen, halogen or (C.sub.1 -C.sub.25) groups containing N, S, and/or O;. and method of making the photoinitiators.. The photoinitiators overcome the leaching problem with prior photoinitiators in radiation curable polymer applications. Radiation curable polymers, cured polymers, and coated articles are also disclosed.

1. Field of the Invention
This invention relates to benzophenone photoinitiators useful in UV curable coating compositions.
2. Description of the Prior Art
Prior benzophenone photoinitiators used in UV curable coating compositions suffered from being leachable because only a fraction of the photoinitiator is consumed during the UV curing process. The large portion of benzophenone which was not consumed remained present in the polymer matrix as a free component, and was leachable upon contact with various liquids, or tended to migrate to the coating surface over time.
Prior attempts to solve the leaching problem with benzophenone photoinitiators in UV curable coating compositions involved incorporating benzophenone into the polyester backbone. U.S. Pat. No. 4,022,674 shows benzophenones with multiple carboxylic acid functionality which react with amine coinitiator. Also, various benzophenone monofunctional (meth)acrylates were synthesized, but they are not practical and not successful because high extractable levels still exist with such photoinitiators. None of the prior attempts to solve this problem have been adequate.
Prior art benzophenones having more than one reactive group had only acid functionality and were suitable for reacting with hydroxyl-functional monomers so as to form polyester linkages. Such linkages are not suitable in UV curable coating systems in which amine coinitiators are present to enhance surface cure.


An amplifier system is provided that can be coupled between a handset and an antenna of a radio frequency (RF) satellite-network communication system. The amplifier system includes a first signal path for amplifying an RF signal received at the antenna when the amplifier system has power supplied thereto. A second signal path is created through the amplifier system when a transmission signal is generated at the handset and the amplifier system has power supplied thereto. A third signal path is created through the amplifier system when no power is supplied thereto. When the third signal path is created, the first signal path and second signal path are disrupted, while the third signal path couples the handset to the antenna.

(1) Field of the Invention
The present invention relates generally to amplifier systems, and more particularly to a bi-directional amplifier system supporting transmit and received signal amplification for half duplex mode operation.
(2) Description of the Prior Art
In some satellite network communication systems, a handset (i.e., any microphone, earpiece and receiver assembly) can be coupled to an antenna via a cable. This is necessary to operate the handset indoors. Many such systems utilize the same frequency for transmit and receive paths in what is known as the half-duplex mode of operation. This is true of the well-known Iridium™ satellite telephone system. In these types of systems, the length of the cable coupling the handset to the antenna in a half-duplex system can be limited by cable losses. Thus, physical constraints imposed by an installation configuration for a half-duplex communication system places a heavy premium (e.g., due to insertion loss limits) on antenna and/or handset placement in order to prevent losses related to cable length. Unfortunately, optimal operational placement is not always compatible with optimal physical placement.

Bi-directional amplifier system for radio communication

The United States of America as represented by the Secretary of the Navy


An easy-open end which comprises a steel sheet and formed on at least one side thereof an about 10-30 mum-thick coating film of a polyester resin having a 50% crystallization time of about 5 minutes or shorter and a coefficient of planar orientation of about 0.04 or lower and which has a groove for cutting which has a cross section having a radius of curvature of about 0.1 to 1 mm; and a laminated steel sheet for use in the easy-open end. This easy-open end can combine suitability for opening and no need of repair even when the residual score thickness is small.

An easy open end is a lid which can easily be opened by a finger without using a jig such as can opener. The material of easy open end mainly adopts aluminum. Aluminum-made easy open end fully occupies the market of beverage cans and food cans. The quantity of aluminum-made easy open end has further increased accompanied with the increasing tendency of adoption of easy open end. The phenomenon suggests that the market does not evaluate the merit of switching the aluminum-made easy open end to the one made by laminated steel sheet.
The steel-made easy open end can be manufactured in a similar manner with the aluminum-made one. That is, a base metal sheet is coated by a resin film for food protection, rust prevention, and other purposes, followed by forming a groove or a carved line, (hereinafter referred to also as score), using a press to allow a finger to easily tear-off the score portion. In the pressing step, however, the resin film is broken to exposemetal in a portion of the lid. Rust is generated at the exposed section with lapse of time for both aluminum-made lid and steel-made lid. On the steel-made lid, however, rust becomes further noticeable, and the product value of the steel-made lid further deteriorates than that of the aluminum-made lid. Accordingly, the steel-made easy open end is subjected to repair by lacquering after the pressing step. The lacquered steel sheet itself is inexpensive as the base material. Since, however, a repair lacquering step is required after score-forming on the lid, economic load becomes heavy. Owing to these reasons, steel sheets are not positively used.
With the background, various trials for eliminating the repair lacquering on the steel-made easy open end have been conducted through the investigations of method for forming score on lid and through the adoption of laminated steel sheet responding to the forming method.
Unexamined Japanese Patent Publication No. 06-115546 tries to eliminate repair lacquering by using a polyester resin and by improving the conventional method for forming V-shape score. Unexamined Japanese Patent Publication No. 09-234534 improves the score-forming method while specifying the thickness and the breaking elongation or resin layer. Unexamined Japanese Patent Publication No. 11-91775 tries to eliminate repair lacquering using a curved surface die for score forming.
However, even in those repair-free technologies for steel-made easy open end, there are cases of incapable of using steel-made easy open end depending on the required level of the contents filled in the can, the design of can and lid, the method for can manufacturing and lid manufacturing, the retorting condition, and the like. Consequently, these technologies are not at a satisfactory level.
In concrete terms, (1) reduction in the score residual thickness by a certain score-forming method results in likely breaking of film, though the openeability (also called the can openeability) improves, thus the elimination of repair lacquering becomes difficult, (2) blushing phenomenon on film occurs during retorting, which is a problems specific to laminate film, and other problems arise. The term "retorting" referred to herein means the heat treatment of a can with packed contents using high temperature steam or the like to thermally sterilize the contents.
Therefore, the market wants a technology that solves these problems. Once attaining the technology, full scale market introduction of the inexpensive laminated steel sheet becomes possible. Furthermore, the significance of the technology does not stay at the reduction in can cost. The substitution of steel for aluminum gives a significant impact also to industries because the all-steel can is superior in the recycle viewpoint and because the steel itself is a base material giving light environmental load compared with aluminum.
An object of the present invention is to solve the above problems and to provide a steel-made easy open end which achieves both openeability and elimination of repair lacquering even with a thin score residual thickness, and to provide a laminated steel sheet as the material therefor. The prevent invention also provides a steel-made easy open end which has excellent blushing resistance during retorting, adding to both of the above performance, and provides a laminated steel sheet suitable as the material therefor.


An indicator device indicating the travel of an air bag-type brake actuator when brakes are applied includes a stationary indicator plate having a cut out extending alongside the path of travel of the actuator. The cut out includes side edges positioned at acceptable minimum and maximum actuator expansion distances giving an indication of proper functioning of the brakes. The device further includes an integral mounting arm for mounting on a plate in the fixed end of the actuator. The mounting arm includes a slot for receiving an upper edge of the stationary measuring plate and a stud on a resilient portion of the arm. An aperture on the stationary measuring plate receives the stud when the arm is mount on it.

Conventional air bag or bellows-type actuators for rail car brakes are typically mounted on the rail car truck bolster. The air bag-type actuators are in construction structurally similar to a bellows. They are formed of a flexible fabric material which expands axially under pressure supplied by the rail car reservoir to move the brake shoes into engagement with the wheels of the rail car. In the description which follows, the terms "air bag-type" and "bellows-type" are used interchangeably. The actuator is pressurized in response to release of air under pressure from the rail car reservoir to cause axial expansion of the actuator which, in turn, moves the brake lever to move the brake shoes into engagement with the wheels of the rail car. Conventionally, the air bag-type actuators are equipped with a pair of plates attached at their movable and fixed ends, termed "measuring plates", which serve the purpose of providing a rail car inspector with relatively movable index marks for measuring the amount of travel of the actuator when the brakes are applied. This is done by the inspector using a tape measure placed against the measuring plates to measure the separation of the plates when the actuator has been inflated to the position in which the brakes are applied. This has proven to be an unduly time consuming procedure when a long string of rail cars needs to be checked, and in practice, the task is too often simply not done.


A device and method of supporting a bicycle load in a workstand, wherein the workstand can be supported on only two members which establish three individual points of support. The workstand can utilize at least one rotatable leg to collapse the workstand into a portable and manageable configuration that facilitates transporting and storage. The load support member to which the bicycle is either directly or indirectly coupled can be coupled to the support base off-center from the geometric center of the support base to provide a more stable configuration for the stand as well as to establish the member out of the way of the bicycle which must be supported. In addition, a space saving footprint established by the support base allows the workstand to be positioned against walls and in corners.

The present invention relates generally to the field of supporting loads such as bicycles and speakers with a support stand. In the support system field one is faced with two conflicting objectives, the first being to provide a sturdy support that will yield the type of support that is required for a heavy load. The second and competing objective is to also provide a support that is capable of easy storage as well as portability. In the past, others have focused on either the portable feature or the substantial structure feature with limited success in combining the two. Furthermore, it is always a goal to provide a support that is easy to manufacture as well as being cost efficient. Often, in many past systems, designers have taken the approach that a symmetrical configuration is the most efficient configuration to provide for a given load. This is often due to the fact that the load is positioned directly on top of the support so that the support structure provides support immediately below the load. However, this approach fails to take into consideration loads which are unbalanced or that are not positioned immediately above the support structure. Rather some loads can be positioned by a clamping arm on the support structure. As a result, these loads that are not either positioned immediately above a symmetrical support or that are positioned by way of a clamping arm often result in the entire support and load assembly being off balance and unstable. As a result these prior designs have left the support in a less desirable configuration than a user of the support would desire.
Furthermore in regard to some types of specific loads such as bicycles or speakers, the prior symmetrical support configurations are particularly undesirable. In the bicycle field it is often necessary to configure the support structure in an area that is cramped for space, such as a garage, a service area in a repair shop, or a display area in a retail store. As one can readily understand such space in a garage, workshop, store, or even an individual's home comes at a premium. Therefore, it is important in utilizing such supports to work on a bicycle to have a support that lends itself towards installation in either a corner or up against a wall.
In regard to speaker assemblies, again it is often a tight space in which such speakers need to be erected. Consequently prior support systems which have utilized symmetrical designs are unfavorable for erecting the speakers in a corner or up against the wall of a concert hall. Furthermore, a speaker presents a heavy load that exerts a substantial force as well as torque on the speaker stand; and, many prior speaker support structures have not provided the substantial support necessary to establish the speakers in a stable position while at the same time offering portability.
In regard to bicycles it is also necessary to be able to work effectively in front of the bicycle support structure. The bicycle often hangs off the support structure such that in some prior designs that utilized a symmetrical support base the legs of the support were oriented such that the user had to step on the legs while working on the bicycle.
In addition the housing of some prior designs which contains the attachment point for the legs of the support stand has often been quite high on the support structure--perhaps even as high as or higher than the waist of the bicycle repairperson. As a result the legs extending from the housing have interfered with the bicycle as it hangs down from the bicycle support stand. This interference has been unacceptable as it prevents the repairperson from effectively working on the bicycle.
Similarly, many prior designs which used a purely symmetrical relationship for their workstands have sacrificed space and efficiency by configuring the load support members of such devices immediately over the center of the symmetrical workstand. In regard to speaker loads and bicycle loads, this has forced those loads to be oriented either on the middle of the support stand or toward the front of the support stand. Much valuable floor space and perhaps stability of the supported load was sacrificed by such an arrangement.
Finally, prior systems have sacrificed either portability or structural support in trying to achieve the goals of providing a stable yet portable support. As a result there is a need for a system which can satisfy these goals and preferably at the same time.


A combined alarm and surveillance system integrates an existing alarm system (12) with an existing surveillance system (14) such that functions unique to each system are combined in a complementary manner. The existing alarm and surveillance systems are combined via an interface (16) comprising an array of electric relays (52,54,56,58,60,62). Each relay receives a signal from either the alarm system or the surveillance system and retransmits the signal to the other system in a form that is compatible with the receiving system. The alarm system is configured to communicate alarm status information to the surveillance system, and the surveillance system is configured to communicate control signals to the alarm system, such as an alarm system reset signal.

1. Field of the Invention
The present invention relates to alarm and surveillance systems. More particularly, the present invention involves a method and apparatus for integrating an existing alarm system with an existing surveillance system such that functions unique to each system are combined in a complementary manner.
2. Description of Prior Art
Surveillance systems including digital video cameras are known in the art and are commonly used in buildings or other sites where security measures require visual observation by a person, automatic motion detection, or video recording. Unfortunately, surveillance systems suffer from various problems and limitations that render them cumbersome or ineffective in certain situations.
For example, while a surveillance system can notify a user of motion detected by a camera, such systems are configured to provide these notifications according to a pre-determined schedule beginning at a certain time of day, such as 7:00 p.m., and ending at another time of day, such as 5:00 a.m. Thus, if an employee or other authorized person desires to work late and remain in the building beyond the scheduled activation time, the surveillance system administrator must be contacted to delay or entirely prevent activation of the notification function. It will be appreciated that where authorized activities frequently occur in the secured area after the scheduled activation time, such measures can become extremely burdensome and may be forgotten, resulting in false notifications.
Accordingly, there is a need for an improved surveillance system that overcomes these, and other, limitations of the prior art.

Security motion sensor and video recording system


A system and method are disclosed for streaming scalable video data over a variable-bandwidth network such as a packet-based one. In other words, the number of bits (for FGS) or sub-layers (for discrete multi-layer scalability) is chosen to be transmitted for each enhancement layer frame. Further, these bits or sub-layers are also partitioned over multiple packets if being sent over a packet-based network. Further, a windowing function is used to smooth the variation in the number of bits or sub-layers transmitted for each frame in situations where the network bandwidth is varying.

The present invention relates generally to video data transmission, and more particularly to a method and apparatus for streaming scalable video over networks having a variable bandwidth.
Scalable video coding refers to coding techniques that are capable of providing different levels or amounts, of data per frame of video. Currently, such techniques are used by such video coding standards as MPEG-2 and MPEG-4 (i.e. "Motion Picture Expert Groups" coding). In the scalable coding techniques employed by these standards, frames of video data are encoded and divided into a base layer and an enhancement layer.
Typically, the base layer includes a minimum amount of data required to decode the coded video data. The enhancement layer, on the other hand, includes additional data that enhances (i.e. improves the quality of) the base layer when decoded. During operation, all frames of the base layer are transmitted to a receiving device. However, the enhancement layer frames are only transmitted if the receiving device has sufficient processing power to handle the additional frames and/or the medium over which the frames are transmitted has a sufficient bandwidth.
One known scalable video technique is fine-granular scalability. Fine-granular scalability (FGS) codes the same image (e.g., a frame of video) using progressively more data each time coding takes place. For example, in a co-pending application entitled "Scalable Video Coding System," Ser. No. 09/110,616, to the same assignee as herein, a system is disclosed for video coding that has the property of fine-granular scalability, in which a base-layer of video is coded at a fixed rate, and a residual or enhancement-layer is coded to cover a wide range of rates.
Presently, the ISO MPEG-4 committee is researching methods for fine-granular coding. Thus, a need exists to come up with a practical method for streaming the enhancement layer. In another co-pending application entitled "System for Controlling Data Output to a Network", Ser. No. 09/177,962, also to the same assignee as herein, a method for streaming data over a packet-based network was disclosed. However, this method was only used in order stream base-layer video over the Internet.

Method and apparatus for streaming scalable video


A coaxial connector (1) has a resilient cantilever beam (23) extending from a central contact portion (6), a beam engaging surface (33) on insulation material (3) to limit movement by deflection of a first resiliently deflectable portion (24) of the beam (23), a tab electrical terminal (27) at an unsupported end of the beam (23), and the beam (23) being curved back on itself adjacent the tab electrical terminal (27) to provide a second resiliently deflectable portion (26) of the beam (23).

A known surface mount, coaxial connector has a central electrical contact with a tab terminal establishing an electrical connection when the solder tab terminal is joined by a solder joint to an electrically conducting pad on a circuit board. Avoiding a solder joint, is desirable, to reduce the cost and the exertion of painstaking care necessary to provide a quality solder joint.
It is desired to provide a coaxial connector that has a central electrical contact with a tab electrical terminal that establishes a surface mount electrical connection without a need for solder. It is known to provide an electrical terminal in the form of a stamped and formed, resilient spring that undergoes resilient deflection to provide sufficient contact pressure of the terminal against a conducting pad on a circuit board. The contact pressure can be elevated to a desired magnitude by increasing the dimensions of the stamped and formed spring. For a coaxial connector, a longer spring length would cause the connector to deviate from its desired characteristic impedance and insertion loss characteristics. For a coaxial connector, its outer diameter dimension is fixed to a standard size to assure intermating compatibility, which means a thicker contact spring for the same outer diameter dimension would cause the connector to deviate from its desired characteristic impedance.


A request is received at a proxy server for a web page, the request originating from a client network application of a client device. The requested web page includes multiple references to multiple images. The proxy server retrieves the requested web page. The proxy server modifies code of the retrieved web page such that the client network application will not, for each one of images, request that image until the location where that image is to be displayed is within a viewport of the client network application or within a defined distance from the viewport of the client network application. The proxy server transmits the modified web page to the client device.

Images can be more than half of the data that makes up a typical website. Although there are tools that may automatically reduce the size of the images on behalf of the website owner, many of the images may not be needed for the page as they may never be seen by the user. For example, some pages are longer than the viewport of the device (a window or other viewable area on the screen) and require the user to scroll to view the entire page. An example of such a page is a blog, which typically is a relatively long page with a series of stories, the most recent of which are on top. When the page is loaded, only the images within the viewport (the visible portion of the client window) can be viewed. However, most client network application such as browsers download all of the images on the page before the page is ready. This may slow down page performance waste bandwidth for images that may never be seen (e.g., if the user does not scroll down to actually view the images that are not on the viewport).
Most client network applications create an image placeholder for each single image that is referenced in a web page. Most images are externally sourced and downloaded by the client network application and are displayed in the location of the corresponding image placeholders. If an image cannot be displayed (e.g., an error occurred when the image was attempted to be downloaded), most client network applications display a broken image or other error display in the location of the corresponding image placeholder.

Method and apparatus for automatically optimizing the loading of images in a cloud-based proxy service


A screening method for fetal Down syndrome using free beta (HCG) as a marker. The maternal blood level of free beta (HCG) is measured and compared to reference data, at a similar gestational age, of the level of free beta (HCG) in pregnant women carrying a fetus with Down syndrome and pregnant women carrying an unaffected fetus. The method may advantageously be utilized during the first and second trimesters of pregnancy. Fragments of free beta and "nicked" free beta may also be utilized as markers.

The present invention relates to a method for detecting fetal Down syndrome (Trisomy 21) during prenatal screening. This method also relates to other more rare but detectable chromosomal trisomies such as Trisomy 13 and Trisomy 18. More particularly the present invention relates to a method for improving detection efficiency in screening for Down syndrome by measuring the amount of the free beta subunit of human chorionic gonadotropin (hCG) in the blood of pregnant women.
Down syndrome, also referred to as Trisomy 21, is the most common congenital cause of severe mental retardation Generally, fetal Down syndrome can be determined by a diagnostic procedure including amniocentesis and karyotyping. However, this diagnostic procedure is invasive and involves risk to the woman and the fetus. Amniocentesis and karyotyping are not routinely performed during all pregnancies. Instead, one or more screening methods may be utilized to determine when the risk to the pregnancy warrants the risk of undergoing an invasive diagnostic procedure.
The incidence of Down syndrome increases significantly with increasing maternal age. Historically, the prenatal search for Down syndrome has focused on pregnant women at and over the age of 35, at which ages the risks of Down syndrome approach or exceed the risks of diagnostic procedures utilized to detect fetal Down syndrome. Therefore the standard method of prenatal screening has involved selecting women for diagnostic amniocentesis on the basis of maternal age. Age, however, is an inadequate screening criterion in that only about 20% of all Down syndrome pregnancies can be detected by carrying out amniocentesis and karyotyping on the 5% of pregnant women most at risk, that is, those aged 35 years or greater. And, because in actual clinical practice only about half of the women aged 35 years or greater undergo amniocentesis and karyotyping, fewer than 10% of Down syndrome pregnancies are prenatally detected.
In 1984 an association between lowered maternal blood alpha-fetoprotein (AFP) levels and fetal Down syndrome was discovered. For example, see "An association between low maternal serum alpha-fetoprotein and fetal chromosomal abnormalities"; Merkatz, Macri, et al.; Am. J. Obstet. Gynecol. 148:886, 1984; the disclosure of which is hereby incorporated by reference. In this publication it was noted that other chromosomal trisomies, in particular Trisomy 13 and Trisomy 18, were also associated with lowered maternal blood AFP levels The incidence of these additional chromosomal trisomies (1 in 5000 pregnancies and 1 in 6600 pregnancies, respectively) is significantly lower than the general a priori risk associated with Trisomy 21 (Down syndrome). However, because of the association of these other chromsomal trisomies with lowered MSAFP levels, such abnormalities will also be detected within a screening protocol utilizing maternal blood AFP and the free beta subunit of hCG and possibly additional markers described herein. It is obvious to those skilled in the art that in using the protocol described herein for Trisomy 21, the detection of Trisomy 13 and 18 may also be accomplished. The association between lowered maternal blood AFP levels and fetal Down syndrome presented the opportunity to use a non-invasive blood screening test in the detection of Down syndrome cases in young, apparently unaffected families where approximately 80% of Down syndrome cases occur. It is estimated that the use of a screening test based on low maternal blood AFP (as a screening marker) would lead to the prenatal detection of approximately 20% of all cases of fetal Down syndrome.
Another method for screening involves measuring the level of unconjugated estriol (UE) in maternal blood. For example, see "Maternal blood screening for Down syndrome in early pregnancy"; Wald, et al. British Journal of Obstetrics and Gynocology (BMJ) Volume 95, April 1988, the disclosure of which is hereby incorporated by reference. The measurement of UE however, provides a poor basis for screening.
More recently an association between elevated maternal blood hCG levels, elevated maternal blood level of the alpha subunit of hCG (hCG is composed of two subunits, hereinafter referred to as alpha-hCG and beta-hCG respectively), and fetal Down syndrome was discovered. For example, see "Abnormal Maternal Serum Chorionic Gonadotropin Levels in Pregnancies with Fetal Chromosome Abnormalities"; Bogart, Pandian and Jones; Prenatal Diagnosis, Vol. 7, 623-630 (1987) the disclosure of which is hereby incorporated by reference. In the Bogart article it is estimated that the use of elevated maternal blood hCG levels and elevated maternal blood levels of the alpha subunit of hCG, would detect approximately 68% of the chromosomally abnormal fetuses. However, these results were obtained from a study on pregnancies at 18-25 weeks of gestation and the affected cases appear to be of women previously identified as being at risk for Down syndrome.
Generally, as suggested above, screening by evaluation of maternal blood hCG has involved only the measurement of hCG in general and additionally the measurement of alpha-hCG. Although these screening methods do detect fetal Down syndrome, there is a need and a desire for a method which detects a greater percentage of fetal Down syndrome cases.
I have discovered a previously unknown association between elevated levels of maternal blood free beta-hCG and fetal Down syndrome. I have also discovered a previously unknown association between the maternal blood level of free beta-hCG and the maternal blood level of AFP and fetal Down syndrome, I have further discovered a previously unknown association between the ratio of the maternal blood level of free beta-hCG to the maternal blood level of the intact hCG molecule and fetal Down syndrome. I have still further discovered that using a multivariate discriminant analysis technique improves the detection efficiency of a screening method using the maternal blood level of free beta-hCG, or the maternal blood level of free beta-hCG and the maternal blood level of AFP, or the log of either, or the log of both, especially when gestational age is also incorporated as a variable in the discriminant analysis technique, for a chosen risk cut-off level. Gestational age refers to the age of the pregnant woman's fetus. Detection efficiency refers to the percentage of cases of fetal Down syndrome which are correctly detected for a chosen risk cut off level. The risk cut off level will be more fully explained in a following section. Discriminant analysis is a generally known approach to multivariate analysis involving the separation of a population into two or more groups by a univariate risk assessment. Discriminant analysis is also sometimes described as a way of constructing a linear combination of independent variables, thus reducing the problem of measuring group differences to a univariate problem. Discriminant analysis can also be performed when there is only one variable involved in a problem. A general discussion of discriminant analysis can be found in Marketing Research; Churchill, G. A.; Dryden, 1976; Chapter 15, pages 530-543, the disclosure of which is hereby incorporated by reference. I have discovered that subjecting the maternal blood levels of free beta-hCG, the maternal blood levels of intact hCG, the ratio of the maternal blood level of free beta-hCG to the maternal blood level of the intact hCG molecule, the maternal blood level of AFP, the maternal blood level of UE, and gestational age to multi-variate discriminant analysis detects a greater percentage, with a lower false positive rate, of fetal Down syndrome cases than any other known screening method for the prenatal detection of Down syndrome. I have further discovered that a still greater number of the cases of fetal Down syndrome may be detected by using only the measurements of the maternal blood levels of free-beta hCG and the maternal blood levels of AFP and subjecting the log of each measurement and gestational age to a multivariate discriminant analysis. These and other discoveries will be more fully explained in the Summary of the Invention section and the Detailed Description of the Invention section.
One object of the present invention is to provide a method and process for screening for fetal Down syndrome which detects a greater percentage of fetal Down syndrome cases with a given false positive rate than other known prenatal screening methods.
Another object of the present invention is to provide a method and process for screening for fetal Down syndrome which has a lesser false positive rate for a given detection percentage than other known methods.
A still further object of the present invention is to apply multi-variate discriminant analysis to methods for screening for Down syndrome to detect a greater percentage of u fetal Down syndrome cases with a lesser false positive rate.
A further object of the present invention is to provide a method and process for screening for fetal Down syndrome by measuring the level of maternal blood free beta-hCG.
A still further object of the present invention is to provide a method and process for screening for fetal Down syndrome by measuring the maternal blood level of AFP and the maternal blood level of free beta-hCG.
Other objects and advantages of the present invention will become apparent in the following description of the invention.

Screening method for detecting fetal chromosal abnormalities


This invention relates to a process for forming a PVC article having a weatherable coating by applying by in-line spray, roll-coat, brush-coat, gravure print, flexographic print, thermal transfer coat or inkjet a polymeric solution onto extruded PVC as it is being extruded. The invention also relates to rigid PVC articles coated by the process. A polyvinylidene fluoride coating can be applied to PVC to form an article having improved gloss, good weatherability, good color retention and stain resistance.

Polyvinyl chloride (PVC) and polyolefin (PO) are economical thermoplastics that can be extruded into many useful articles. Unfortunately, PVC and polyolefin articles discolor, lose gloss, become chalky in appearance and embrittle if exposed to sunlight for extended periods of time. The discoloration and embrittlement is especially detrimental for articles intended for long-term weather exposure, such as house siding, window frames, rain systems, soffits, trim, pipe, panels, etc.
Many approaches have been used to improve the performance of the PVC and PO articles. Stabilizer systems such as lead stabilizers, calcium-zinc stabilizers, and the use of high levels of titanium dioxide pigment have be employed in the PVC resin.
An alternative method has been to employ a thin weatherable capstock over the PVC or PO substrate applied as a laminate or by co-extrusion. The capstock may be stabilized PVC, or a non-PVC polymer. Acrylics have been favored as capstocks for their color stability in outdoor exposure, however they are higher in cost. Film laminates of polyvinylidene difluoride have also been used. Several patents which describe the use of weatherable laminates for rigid PVC substrate compositions include EP 1061100; EP 0473379; U.S. Pat. Nos. 4,141,935; 4,169,180; 4,183,777, 5,306,548; and 5,976,671.
The problem with capstock and laminate processes is that they require a second piece of extrusion or laminating equipment that the throughput rates must be matched to account for differential cooling. Additionally, there is a significant loss of time and material wastage when the production line switches from one color to another. A further difficulty arises in the production/fabrication of dark colored PVC or PO articles, as the slower heat dissipation from the formed article causes production issues as well as occasional failure in the field (delamination, embrittlement, color loss, gloss loss, chalking).
U.S. Pat. No. 5,972,514 describes a means of coating a PVC substrate with a polymer coating using an air or airless spray, or an electrostatic process. The coating is then crosslinked by IR radiation.
Inkjet printing onto non-absorbant plastic substrates, such as transparencies, is known in the art, such as in U.S. Pat. No. 5,555,006.
KYNAR polyvinylidene coatings are formed onto flexible PVC by means of lamination of a pre-printed, pre-coated or clear PVDF flexible film.
There is a need for a better in-line method of forming a weatherable protective coating onto a rigid PVC or PO substrate.
Surprisingly it has been found that a weatherable protective coating can be formed onto a PVC or polyolefin extruded substrate by the in-line application of a polymeric solution or suspension by means of inkjet, brush-coat, roll-coat, gravure printing, flexographic printing, thermal transfer printing or spray application. A further advantage of inline coating application by any of these methods is that color designs are easily created and readily customized or adjusted or matched on the extruded PVC or polyolefin.

Process for forming a weatherable polyvinyl chloride or polyolefin article


A method for the low-loss regulation of a collectorless direct current motor and a semiconductor circuit has, during the commutation phase given by a position sensor and with reduced motor output and number of revolutions, transistors or one end transistor which initially operates temporarily as a switch and thereafter operates temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.

The present invention relates to a collectorless direct current motor equipped with a fan or for driving a fan and including a permanent magnet rotor in the field of at least one stator winding and to a method of operating such a motor. In particular, the invention relates to a driver circuit for a collectorless direct current motor including a permanent magnet rotor having at least two poles and at least one stator winding connected to the driver circuit end stage which temorarily operates as a switch and a sensor detecting the position of the rotor, with the control signal fed to the end stage during each commutation phase causing the current in the stator winding to have a ramp-shaped configuration.
Such a driver circuit is disclosed in No. DE-OS 3,107,623 and includes an RC member with the aid of which rectangular signals are reshaped to control the direct current motor in order to reduce the steepness of their edges, thus reducing the winding noise of the motor. However, in the known driver circuit, there exits neither a possibility to change the number of revolutions nor a possibility to regulate the number of revolutions as a function of an external physical value independently of the operating voltage.
It is known to detect the position of the rotor by means of at least one galvanomagnetic element, a Hall generator or the like, and to use the signal generated in this element, which is a function of the rotor position, to control, by way of semiconductor elements, the currents in one or a plurality of stator windings.
The control circuits employed for this purpose are supplemented by members which regulate the number of revolutions as a function of externally detectable physical values with an otherwise constant operating voltage. Regulation of the number of revolutions may be controlled as a function of various parameters or it may involve an adjustment of the number of revolutions of a fan driving motor which provides ventilation that is automatically adapted to demands for a stream of air. In this case, the fan may be part of a device to be cooled which heats up to different temperatures and whose heat is to be dissipated by the fan. In that case, the heat to be dissipated would be the external physical command variable which determines the regulation of the number of revolutions.
Not only for this exemplary case of use but quite generally, users or manufacturers of such direct current drives desire to make available the smallest possible motors for their space-saving advantages. Power losses should be kept low.
To vary the output of motors operated with a constant operating voltage, it is known to pulse width modulate the motor current. In this case, a low pulse frequency in the audible frequency range is selected. Such a frequency does not produce much additional power loss and does not radiate much interference onto adjacent devices, but it does have the drawback of developing a considerable amount of additional noise. Therefore it is also known to select a high pulse frequency in order to reduce noise. Then, stray high frequency fields result which interfere with the devices with which the fans and the corresponding direct current drives are associated. The simplest regulation employs a rough turn-on and turn-off range with the drawback of restless, rumbling motor operation. The demand for small structures gives rise to the additional desire to integrate the components employed in the circuits and to combine them in a chip. Therefore, the power losses in the integrated active and passive components employed must be kept low so that the components can be placed in close, juxtaposition and encapsulated. This demand is counter to the necessity of allowing sufficient current to flow in the electromagnetic peaks then occur in the control circuits and the heat generated by these peaks must not be permitted to destroy the integrated electronic components.

Collectorless direct current motor, driver circuit for a drive and method of operating a collectorless direct current motor


Apparatus and methods for selecting a transmit power level and subcarrier modulation assignments based on measured channel conditions to achieve a performance level for communications over a symbol-modulated subcarrier communication channel are provided. In some embodiments, the transmit power level may be changed depending on whether a desired packet error rate and/or a desired link data rate can be achieved based on selected subcarrier modulation assignments and a selected transmit power level.

Some wireless local area networks employ multi-carrier transmission techniques, such as orthogonal frequency division multiplexing, in which symbol-modulated orthogonal subcarriers are used to transmit information. The use of orthogonal subcarriers allow the subcarriers to be spaced much more closely together within an available spectrum than, for example, the individual channels in a conventional frequency division multiplexing (FDM) system. Before transmission, the subcarriers may be modulated with a low-rate data stream. The transmitted symbol rate of the symbols may be low, and thus the transmitted signal may be highly tolerant to multipath delay spread within the channel. For this reason, many modern digital communication systems are using symbol-modulated orthogonal subcarriers as a modulation scheme to help signals survive in environments having multipath reflections and/or strong interference.
Many conventional communication systems achieve higher throughput by operating at a maximum transmit power level. These systems, however, do not consider the effects that transmit power level may have on other communication devices. Furthermore, these systems do not consider network information, the data type and the application for determining transmit power lever, as well as other communication parameters for communicating.

Apparatus and methods for communicating using symbol-modulated subcarriers


A method for comparing text in a first file to text in a second file. The method includes segmenting text in the first and second files to one word per line; comparing the segmented versions of the versions of the first and second files on a line by line basis; creating a result file using the segmented version of the first file; and augmenting the result file with indication of error using a sandwiching technique. This sandwiching technique includes identifying correct segments that are immediately adjacent any differences identified by comparing the segmented versions of the first and second files on a line by line basis toward sandwiching the erroneous segments between correct segments. Said method incorporates video monitor (26), keyboard (24), and mouse (23), along with microphone (25) and digital recorder (14) for implementing the invention.

1. Field of the Invention
The present invention relates in general to text comparison programs and, in particular, to a system and method for comparing text generated in association with a computer speech recognition systems.
2. Background Art
Speech recognition programs are well known in the art. While these programs are ultimately useful in automatically converting speech into text, many users are dissuaded from using these programs because they require each user to spend a significant amount of time training the system. Usually this training begins by having each user read a series of pre-selected materials for approximately 20 minutes. Then, as the user continues to use the program, as words are improperly transcribed the user is expected to stop and train the program as to the intended word thus advancing the ultimate accuracy of the acoustic model. Unfortunately, most professionals (doctors, dentists, veterinarians, lawyers) and business executive are unwilling to spend the time developing the necessary acoustic model to truly benefit from the automated transcription.
In response to this problem in the art, the assignee of the present application has previously filed a patent application directed to a system that offers expedited training of speech recognition programs. As an associated part of that system Applicant provided a simplified means for providing verbatim text files for training the aural parameters (i.e. speech files, acoustic model and/or language model) of a speech recognition portion of the system.
In this previous disclosure, Applicant utilized a common text comparison technique. While this approach generally works reasonably, in some instances the basic text comparison techniques do not work well in conjunction with text generated by a speech recognition program. For instance, speech recognition program occasionally produce text combining or altogether omitting certain spoken words. In such instances, it is extremely complicated to use standard text comparison programs to support the automated training of a speech recognition engine.
Accordingly, it is an object of the present invention to provide a text comparison program capable of handling the types of errors commonly produced by speech recognition program speech to text conversions.
These and other objects will be apparent to those of ordinary skill in the art having the present drawings, specification and claims before them.

System and method for identifying an identical audio segment using text comparison


An apparatus for controlling printing or display of documents represented in a structured hierarchal page description language. Documents are provided as a document data stream which can include references to external references and external data declarations which can be incorporated into the document by the content processor. Documents are defined by a prologue section which may contain definitions and declaratory commands, with content portions containing specific tokens or command for specific images. The document data stream has a hierarchal structure. A means to provide external declarations is provided which will process external declarations as if the external declaration which can be stored on a separate device were part of the original document data structure. The storage of the references to the external declarations is accomplished in a tree linked stack structure with a last in first out arrangement which allows for a faster search order of external declarations. The tree linked stack structure further allows for the correct external declaration to be associated with a given reference thereto, even if different external declarations within the document data stream might have the same name. The context of the document data stream and the level in which a call is made determines the exact external declaration which is being referenced. This provides an incorporation by reference ability to a document data stream.

1. Field of the Invention
This invention relates generally to computer controlled printing of documents having text and graphical components and more particularly to a method and system for inclusion of external files, represented in a structured page description language, into a data stream intended to be printed or displayed. It is particularly useful for the automatic translation between different data and printing formats which are suitable for use with a variety of presentation devices and/or for the transmission of data to other devices in a communication system. In this context the presentation of a document on a page involves the printing on a fixed medium such as paper, transparency or the like, a page, or presenting on a visual display a page or transmitting to another device the document in a form to be presented or stored. The present application is related to commonly owned co-pending U.S. patent application Ser. No. 07/778,578 filed on Oct. 17, 1991, the disclosure of which is incorporated by reference herein. The present application is also related to commonly owned concurrently filed U.S. patent application Ser. No. 07/876,601 entitled "A Method and Apparatus to Manage Picture and Pageset for Document Processing" filed on Apr. 30, 1992, also incorporated by reference herein.
2. Discussion of the Background
The development of laser printers in the early 1970s provided an opportunity for high quality low cost printing of documents which contain not only character text but also general graphical material. The primary method of controlling commands by the computer to the printer employed the so called "escape sequence" commands similar the type commands used in the DIABLO.RTM. command sequence. These types of commands were distinguished from typical character data by preceding each command with a special byte, generally an escape character (ASCII 27). This methodology worked in an acceptable manner with daisy wheel or dot matrix printers but is not well suited for printing documents that combine both text and graphical materials in that no provision is made for the large amount of data that a graphic might need. It also does not allow for the inclusion of external files into a data stream in an expeditious manner.
As a response to the limitations inherent in the case of the escape sequence commands, different types of "page description language" (PDL) were developed generally to control laser printers or other types of page printers. Backward compatibility was provided to most of these laser printers in that they were generally able to accept escape sequence commands. Examples of page description language are the PostScript.RTM. system from Adobe Systems Incorporated and InterPress.RTM. from Xerox.RTM. Corporation. Several other proprietary PDL's are also known.
The prior art page description languages provided various improvements to the standard escape sequences known previously, such as providing tools and syntax for resource declarations, context declarations, dictionaries, the use of memory stacks or the like. These languages also in some cases allowed for dynamic changes in the printers state, such as the ability to add fonts or to add graphical images to the resources that might be available to the printer. Some of these features are documented in such generally available reference works as Adobe System Incorporated's "PostScript Language Reference Manual" and the "PostScript Language Program Design", both by Addison-Wesley Publishing Company. Other PDL's are likewise described in various technical and reference books such as "InterPress, The Source Book" by Harrington et. al. (Simon and Schuster, Inc., 1988)
A standardized page description language has been proposed and is in the process of being developed as an international standard. The proposal, to which the present inventor is a contributor, at this stage is in draft form before a section of the ISO. The draft is known as ISO/IEC DIS 10180 and is labeled "Information Processing- Text Communication- Standard Page Description Language". The current draft is dated 1991.
Many of the prior art types of page description languages suffer from various flaws, including the fact that they are generally limited to an individual page and are do not generally employ a fully structured language. For example, one of the shortcomings of the PostScript.RTM. language is that the page description for a particular document can contain a new definition such as a resource definition (for example an additional font) or a new dictionary definition which can be used anywhere in the document. As a result of this, the entire content of the document must be processed in order to determine whether a particular printer has the resources that are necessary to print it. Alternatively, if this "preprocessing" is not performed it is possible that the printing of a document may fail at any point during the printing process, even at the very end, due to the inability of the printer to comply with commands of the document page description.
Additional problems are associated with the prior art systems that employ PostScript.RTM. in that in order to print a given page of a document it is generally necessary to read at the beginning of each page the entire PDL description of all the preceding pages of the document in order to determine the state of the document page setup parameters (i.e., resource declarations, dictionary definitions or the like). In other words, a print control or print drive program must read the entire PDL description of a document to take into account the effect of every page setup command between the beginning of the document and the specified page. While this page setup scanning process is relatively straightforward it does require a significant amount of processor time which can be better used by the printer.
Additionally there is no syntax or semantics defined in the PostScript.RTM. language to handle the inclusion of external entities, nor is there any easy method to add this feature.
One of the problems with the well known InterPress.RTM. system from Xerox.RTM. is that its structure does not allow for both "clear text" or binary data streams to be used interchangeably.
The ability to add external entities to a document data stream allows for a "global" type of change to be provided in documents whereby a library of "style" standardizations can be easily created so that standardized or set styles can be defined for work groups, departments or enterprise-wide operations.

Method and system to handle inclusion of external files into a document processing language