This invention relates to measurement of error characteristics of a communication channel. The invention is of particular use for measuring perceived transmission performance of the communication channel. The invention provides a method and apparatus for measuring the transmission error characteristics of a channel employing frame based transmission in which a frame classification indicator is generated for an expected frame, according to data received via said channel, and in which the following steps are repeatedly performed: generating frame classification data relating to the expected frame; updating a statistical representation of the transmission error characteristics according to said frame classification. The invention also provides a method and apparatus for measuring perceived transmission performance of a communications channel in which the perceived transmission performance is generated according to measured transmission error characteristics.

This invention relates to measurement of error characteristics of a communication channel. The invention is of particular use for measuring perceived transmission performance of the communication channel.
Signals carried over telecommunications links can undergo considerable transformations, such as digitization, compression, encryption and modulation. They can also be distorted due to the effects of transmission errors. It is highly desirable to be able to determine the combined effect of such transformations and transmission errors on the quality of the received signal as perceived by a human.
The present invention is concerned with channels employing transport of frames of data. Packet based communication systems such as the Internet Protocol (IP) defined in Internet Engineering Task Force (IETF) request for comment (RFC) number 791 are a good example of a frame based communication system. Packet systems typically comprise a number of routing nodes that buffer data prior to forwarding packets towards their final destination. A feature of such networks is that the time taken for packets to transit the network is not constant because the buffering delay at each node depends upon its instantaneous load level. This variation in packet transit times is often called jitter. In a complex packet system, such as a wide area network (WAN), individual packets belonging to a media stream may take different routes, and hence packets may arrive at their destination in a different order.
The most common form of transmission error in packet networks is packet loss, which occurs when a packet is discarded at the final receiver or at an intermediate routing node. In general, a packet is discarded because:                transmission errors have been detected in the contents of the packet;        a buffer is full and the packet cannot be stored;        the packet has arrived too late to be of use;
Packet systems that transport real-time data such as speech, audio and video streams often employ a protocol to compensate for the effects of variable transmission delay, packet reordering and packet loss. A good example is the real-time transport protocol (RTP) defined in IETF RFC number 1189. RTP is intended to be operated over an IP network using the user datagram protocol (UDP) defined in IETF RFC number 768. In addition to the encoded media data, RTP packets include a sequence number and a timestamp—the sequence number facilitates the reordering of packets that arrive out of order, the identification of late packets and the detection of missing packets; the timestamp is used to buffer packets at the receiver such that the net transmission delay is constant. The buffer at the receiver is sometimes referred to as a jitter buffer. The additional delay introduced by the jitter buffer is a trade-off between minimising the overall delay of the communication channel and minimising the number of packets discarded due to late arrival. In some schemes, the buffering delay can be changed adaptively to match changes in jitter statistics. In an IP communication system, the detection of transmission errors in packets is often performed by the link layer, for example ethernet.
In a typical implementation, frames of data extracted from packets in the jitter buffer are passed to a signal decoder in the order in which they were originally generated by a signal encoder. If a frame of data is missing due to a lost or late packet, this is indicated to the signal decoder by means of frame classification data. In its most simple form, the frame classification may be a binary flag indicating whether valid data is available or not. If a packet containing multiple frames of data is lost, all of the corresponding frames will be marked as being unavailable.
In the event of missing data, the signal decoder will typically produce an output signal with a duration corresponding to the missing input data. This is necessary to keep the delay across the communication channel constant. One solution to lost packets in a speech system is to mute the output of the signal decoder for the period corresponding to the missing data. A more effective solution frequently used in code excited linear predictor (CELP) speech decoders is to repeat the last known value of parameters that are known to change slowly, such as pitch and linear predictor coefficients, and to synthesise random values for the other parameters, such as the stochastic codebook index. A strategy used in video decoders it to simply freeze the output. Such techniques are commonly called error concealment in the art.
In a radio system employing frame based transmission, symbol errors may occur when a transmitted symbol is incorrectly decoded by a receiver. Many transmission schemes include forward error correction (FEC) techniques that allow a limited number of transmission errors to be corrected. The symbol errors that are introduced by the transmission link are commonly called raw errors, whilst errors that remain after the application of FEC decoding are commonly called residual errors. If there is no FEC then the residual errors are equivalent to the raw errors.
Bad frames are frames of data that contain symbol errors that have been detected, but not corrected. The error detection mechanism may be a by-product of an FEC scheme or the result of a specific checksum calculation. In some schemes, a frame of data is classified as bad if an error is detected in any symbol position. In other schemes, a frame is only classified as bad if errors are detected in particular symbol positions within the frame. This latter technique is often used in unequal error protection (UEP) transmission schemes.
UEP is frequently employed in speech or video transmission systems where the contribution of a symbol to the perceived quality of the transmission depends upon its position within a frame. The error protection scheme is said to be unequal if more powerful FEC is applied to the most important symbol positions at the expense of weaker protection of less important symbol positions. Groups of symbols that receive the same level of FEC are said to belong to the same symbol class. UEP schemes typically only provide a checksum for the most important symbols, and hence only those frames received with a residual error in one or more of the most important symbol positions are classified as bad frames. This approach has been found to yield better overall transmission quality in systems where the presence of residual errors in the least important symbols is, on average, less deleterious than the effect of discarding every frame that contains one or more residual errors. A good example of such a UEP scheme is that specified for the global system for mobile communications (GSM) adaptive multi-rate (AMR) speech service in European Telecommunications Standardisation Institute (ETSI) technical specification GSM 05.03.
For any checksum, there is a finite probability that the checksum will be valid for a corrupted frame. For very short checksum lengths, this probability can become significant and undetected bad frames can become a problem. In this situation, it is common to implement additional bad frame detection techniques—many examples being based on the internal variables of a Viterbi FEC decoder. Such additional checks only indicate the probability that a frame is corrupted, and may therefore be classified differently to an invalid checksum. In a variation of bad frame classification, the AMR speech service described in the ETSI GSM specifications provides a class for frames with uncorrupted Class 1 bits (the most important bits) and the possibility of errors in the Class 2 bits (which are not protected by the checksum).
Bad frames in a radio system may be handled in much the same way as described for the packet based system described above.
Variable rate coding is a known form of signal coding whereby the encoding rate can be changed on a frame-by-frame basis. The rate may be changed according to characteristics of the input signal or due to knowledge of the capacity of the transmission network. In a variable rate communication system, the data passed to the signal decoder may therefore have a multi-level frame classification that includes an indication of the rate at which the data was encoded.
Layered or embedded coding is a known form of signal coding whereby encoded data is divided into so-called 'core data' and 'enhancement data'. The core data is the minimum information required to generate an output frame at the decoder without using error concealment techniques. The enhancement data is used to improve the perceived quality of the decoded signal, if available. The advantage of layered coding is that enhancement information can be sent in packets marked as being lower priority than packets containing core information. During periods of congestion, routing nodes can discard the lower priority enhancement packets to reduce the number of lost core packets. In a layered communication system, the data passed to the signal decoder may therefore have a multi-level frame classification that indicates which layers (or types of data) are available (if any).
Other examples of systems where packets or frames of information may be classified according to detected transmission errors in a received frame include radio communication systems such as that described in the Third Generation Partnership Project (3GPP) series of specifications for a so-called third generation public land mobile radio system (PLMN).
Objective processes for the purpose of measuring the perceived quality of a signal are currently under development and are of application in equipment development, equipment testing, and evaluation of system performance.
A number of patents and applications relate to this field, for example, European Patent 0647375, granted on 14th Oct. 1998. In this invention two initially identical copies of a test signal are used. The first copy is transmitted over a communications system under test. The resulting signal, which may have been degraded, is compared with a reference copy to identify audible errors in the degraded signal. These audible errors are assessed to determine their perceived significance—that is, errors that are considered significant by human listeners are given greater weight than those that are not considered so significant. In particular inaudible errors are irrelevant to perception and need not be assessed.
This system provides an output comparable to subjective quality measures originally devised for use by human subjects. More specifically, it generates two values, YLE and YLQ, equivalent to the "Mean Opinion Scores" (MOS) for "listening effort" and "listening quality", which would be given by a panel of human listeners when listening to the same signal. The use of an automated system allows for more consistent assessment than human assessors could achieve, and also allows the use of compressed and simplified test sequences, which give spurious results when used with human assessors because such sequences do not convey intelligible content.
In the patent specification referred to above, an auditory transform of each signal is taken, to emulate the response of the human auditory system (ear and brain) to sound. The degraded signal is then compared with the reference signal after each has been transformed such that the subjective quality that would be perceived by a listener using the network is determined from parameters extracted from the transforms.
Such automated systems require a known (reference) signal to be played through a distorting system (the communications network or other system under test) to derive a degraded signal, which is compared with an undistorted version of the reference signal. Such systems are known as "intrusive" measurement systems, because whilst the test is carried out the channel under test cannot, in general, carry live traffic.
Measurement systems that do not require a reference signal are known as "non-intrusive". A description of such a system is provided in the literature (Non-intrusive speech quality assessment using vocal-tract models, Gray P.; Hollier M. P.; and Massara. R. E.; IEE Proceedings—Vision, Image and Signal Processing, 147 (6), 493–501, December 2000.). Such systems are not, in general, as accurate as intrusive measurement systems but have the advantage that they can be used on revenue earning traffic.
German patent application DE 4324292 discloses the measurement of a bit error rate (BER) over a period of time, the formation of a statistical representation therefrom, and the use of a transform to map the statistical representation to a measure of the speech quality of a digital mobile radio system. The invention is characterised by the fact that the mapping is derived from the results of subjective experiments. The application discloses the derivation of speech quality based on the analysis of BER and the use of the mean, standard deviation and probability distribution of a plurality of bit error measurements. Patent application DE 4324292 does not describe the use of a frame classification algorithm. The only specific means of generating the required bit error information described in the embodiment and claims of DE 4324292 is the RXQUAL parameter produced by GSM systems. RXQUAL is a coarse estimate of BER prior to channel decoding measured over a period of 480 ms (in other words the raw BER). However, it is known that the ability of a FEC decoder to correct errors depends on the bit-by-bit burst characteristics of the raw errors. Such detailed burst information is lost in the averaging over 10,944 bits performed in the RXQUAL calculation, and the embodiment described in DE 4324292 is unlikely to provide a reliable estimate of speech quality across a wide range of radio propagation conditions. This conclusion is confirmed in the literature (Radio link parameter based speech quality index-SQI; Karlsson, A.; Heikkila, G.; Minde, T. B.; Nordlund, M.; Timus, B.; Wiren, N; Proceedings of ICECS '99. The 6th IEEE International Conference on Electronics, Circuits and Systems, Volume: 3, 1999 Page(s): 1569–1572 vol. 3).
US patent application U.S. Pat. No. 6,157,830 discloses an arrangement whereby radio link parameters are converted into a set of temporal parameters that are combined to yield a set of correlated parameters that are in turn mapped into a speech quality measure by means of an estimator. This patent discloses the derivation of temporal parameters from measures of raw BER over 0.5 second intervals, the mean frame erasure rate calculated over a 5 second interval and the calculation of the number of consecutive frame erasures in a 5 second interval. The patent goes on to disclose the statistical analysis of the temporal parameters, providing maximum value, minimum value, mean value, standard deviation, skewness, and kurtosis as examples.
International patent application WO 01/97414 describes a method of determining the perceived quality of a speech transmission system by using a measure of link quality to retrieve a previously stored perceived quality score calculated for the same link quality. The pre-calculation of the perceived quality score for a given link quality is performed by: 1) using a description of the link quality to degrade a copy of a test signal; 2) deriving the corresponding perceived quality score by using an intrusive objective speech quality measurement algorithm to compare the degraded version of the test signal with an undegraded version. WO 01/97414 discloses that bit error rate, packet delay variation, and packet loss characteristics (number of packets lost and any pattern to them) are suitable measures of the link quality for mapping to a perceived quality score, but does not provide any specific description of statistical representations of these parameters.

Method and apparatus for transmission error characterization


A disk reproducing apparatus capable of loading a compatible cartridge and MO cartridge designed to different specifications comprised a cartridge holder unit having a first shutter opener for opening and closing a shutter on the first cartridge and a second shutter opener for opening and closing a shutter on the second cartridge, the second shutter opener being moved outside or inside the cartridge insertion path depending on the cartridge inserted, and a disk motor base unit having first and second reference posts for adjusting the respective disk mounting distances of the first and second cartridges

1. Field of the Invention
The present invention relates to a disk reproducing apparatus capable of loading two different kinds of cartridges designed to different specifications, and used for an information storage device such as a data file storage device or an image file storage device, and also relates to a compatible cartridge used with the same apparatus.
2. Description of the Related Art
Write-once and rewritable optical disks are provided, each permanently encased in a cartridge to protect the optical disk from dust and other foreign particles. A prior known cartridge will be described with reference to FIGS. 15 and 16.
FIG. 15 shows an example of a conventional, single-sided cartridge. FIG. 15 is a perspective view showing a cartridge 101 (hereinafter referred to as the MO cartridge), with its front surface facing up, that conforms to international standards defining a 90-mm magneto-optical disk. FIG. 16 is a perspective view of the same MO cartridge 101 with its back surface facing up.
The MO cartridge 101 consists primarily of a case body 102 encasing a single-sided 90-mm magneto-optical disk with a substrate thickness of 1.2 mm (hereinafter referred to as the MO disk), and a U-shaped shutter 104 fixed to a slider 103 slidably mounted to the case body 102.
The outer dimensions of the MO cartridge 101 are 90 mm in length, 94 mm in depth, and 6 mm in height. The front surface of the case body 102 has a first opening 105 through which a bias magnet is inserted and positioned inside the case body 102 during recording or reproducing. On the back surface of the case body 102, there is formed a second opening 106, through which a disk motor and an optical pickup are inserted and positioned inside the case body 102. On the back surface, there are formed positioning holes 107 and reference faces 108 used to hold the MO cartridge 101 in position.
In both side faces of the case body 102 are formed slots 109 for an autochanger and semi-circular recesses 110 for auto loading. A corner notch 111 is formed on one corner of the inserting side of the case body 102 to prevent the MO cartridge 101 from being inserted incorrectly.
The shutter 104, constructed to slide over the outer surfaces of the case body 102, is urged by a torsion spring (not shown) installed inside the case body 102 in a direction that closes the first opening 105 and second opening 106. The back end of the U-shaped shutter 104 is held by a shutter holding plate 112 so as to be guided therealong in sliding fashion
Next, a prior art loading mechanism designed to accommodate the above-described MO cartridge 101 will be described with reference to FIG. 17.
FIG. 17 is a perspective view showing the prior art MO cartridge loading mechanism. In FIG. 17, arrow Y indicates the direction in which the MO cartridge 101 is inserted.
A cartridge holder 121 for holding the MO cartridge 101 in position is shaped in the form of a tray with both sides thereof bent as shown. A support shaft 122 is formed in protruding fashion on the right rear corner (the uppermost portion in FIG. 17) of the cartridge holder 121. On this support shaft 122 there is mounted a shutter opener 123 having a shutter opener pin 123a at its end. The shutter opener 123 is pivotably supported on the support shaft 122 and is urged in the direction of arrow X by a torsion spring 124. On the left rear corner of the cartridge holder 121, a pawl 125 is formed in an inwardly protruding fashion for preventing the MO cartridge 101 from being inserted incorrectly.
Next, the loading operation of the MO cartridge 101 will be described.
When the MO cartridge 101, with its front surface facing up, is inserted into the cartridge holder 121 of FIG. 17 in the direction of the arrow Y, the shutter opener pin 123a on the shutter opener 123 comes into contact with the rightmost end of the slider 103 on the MO cartridge 101. As the MO cartridge 101 is further inserted, the inserting force causes the shutter opener pin 123a to push the rightmost end of the slider 103, thus causing the slider 103 to slide along the case body 2. By moving the slider 103 against the force of the torsion spring 124 in this way, the shutter 104 is moved in the direction that opens the first opening 105 and second opening 106.
When the MO cartridge 101 is further inserted into the cartridge holder 121, the first opening 105 and second opening 106 become completely exposed, and the shutter opening operation is thus completed.
When the shutter opening operation is completed, the MO cartridge 101 is positioned with its notch 111 facing the pawl 125 of the cartridge holder 121. The pawl 125, however, is not in contact with the notch 111, and the MO cartridge 101 can thus be inserted as far as to the prescribed position.
After the shutter opening operation is completed, positioning pins (not shown) provided inside the apparatus are inserted in the positioning holes 107 formed in the inserted MO cartridge 101. At the same time, reference posts (not shown) provided inside the apparatus abut against the reference faces 108 formed on the case body 102, thus holding the inserted MO cartridge 101 in position. Also at this time, the clamping face of the MO disk inside the MO cartridge 101 is mounted on the turn table of the disk motor, and the loading operation of the MO cartridge 101 is thus completed.
Disk mounting distance (hereinafter referred to as L1), which is the distance from the reference faces 108 on the case body 102 of the MO cartridge 101 to the clamping face of the MO disk, is specified as 2.4 mm by the standard defining the MO cartridge 101.
Next, an operation will be described when the MO cartridge 101 is inserted upside down or backwards into the cartridge holder 121. When the MO cartridge 101 is inserted in the cartridge holder 121 in such an abnormal manner, the shutter 104 cannot be opened by the shutter opener pin 123a because the shutter opener pin 123a does not come into contact with the rightmost end of the slider 103 on the MO cartridge 101.
Furthermore, since a corner other than the corner notch 111 of the MO cartridge 101 strikes against the incorrect insertion prevention pawl 125 in the cartridge holder 121, the MO cartridge 101 cannot be inserted as far as to the correct position. Accordingly, the positioning pins inside the apparatus do not engage with the positioning holes 107.
In this way, when the MO cartridge 101 is incorrectly inserted, the shutter 104 is not opened, and the MO cartridge 101 cannot be loaded with its shutter 104 prevented from being opened.
With increasing demand for higher-density of recording and thinner optical disks in recent years, a double-sided disk formed from two disk substrates each with 0.6 mm thickness laminated together has been developed. A double-sided cartridge for housing such a double-sided disk is disclosed, for example, in Japanese Patent Unexamined Publication No. Hei 6-267226.
Such a prior known double-sided cartridge will be referred to simply as the double-sided cartridge, as opposed to the MO cartridge. The construction of the double-sided cartridge will be described below with reference to FIG. 18, which is a perspective view showing the double-sided cartridge 131 containing therein a double-sided disk. The construction of the double-sided cartridge 131 is substantially the same both on its front and back. For simplicity, the explanation will be given using FIG. 18 that shows the double-sided cartridge 131 with its front surface facing up.
This prior art double-sided cartridge 131 consists primarily of a case body 132 and a U-shaped shutter 133 fixed to a slider (not shown) slidably supported inside the case body 132. The outer dimensions of the double-sided cartridge 131 are 90 mm in width, 94 mm in length, and 5 mm in height. The front and back surfaces of the case body 132 each have an opening through which the disk motor and optical pickup are inserted and positioned inside the case body 132. Further, on both the front and back surfaces of the case body 132, there are formed positioning holes 135 and reference faces 136 for positioning the double-sided cartridge 131 in prescribed loading position. A groove 137 is formed on each of the right and left sides of the case body 132 in the forward portion thereof as viewed in the direction of the disk insertion. A slot 138 for an autochanger is formed on each of the right and left sides of the case body 132 in the rearward portion thereof.
An opener belt 139 connected to the shutter 133 via the slider is slidably guided along one of the grooves 137 formed on both sides of the case body 132. A shutter opener hook 140 is attached to one end of the opener belt 139.
The shutter 133 is urged by a torsion spring (not shown) installed inside the case body 132 in such a direction as to open an opening 134. Both ends of the U-shaped shutter 133 are held and guided in sliding fashion between shutter holding plates 141 mounted on the outer surfaces of the case body 132.
The opening 134, positioning holes 135, and reference faces 136 formed in the case body 132 are identical in shape and position to the corresponding portions of the earlier described MO cartridge 101. However, because of the double-sided construction, the double-sided cartridge 131 does not have the corner notch 111 nor the auto loading semi-circular recesses 110 of the MO cartridge 101.
Next, a prior art loading mechanism designed to accommodate the above-described double-sided cartridge 131 will be described with reference to FIG. 19. FIG. 19 is a perspective view showing one example of a prior art double-sided cartridge loading mechanism.
A cartridge holder 151 for holding the double-sided cartridge 131 is shaped in the form of a tray by using a plate with both sides thereof bent as shown. On each side of the cartridge holder 151 is formed a shutter opener pawl 152 that can enter the groove 137 on the double-sided cartridge 131 and can engage on the opener hook 140.
Next, the operation to insert the double-sided cartridge 131 in the cartridge holder 151 will be described.
When the double-sided cartridge 131 is inserted into the cartridge holder 151, the shutter opener pawl 152 of the cartridge holder 151 enters the groove 137 of the case body 132 and engages on the shutter opener hook 140. As the double-sided cartridge 131 is further inserted into the cartridge holder 151, the shutter opener hook 140 is pressed against the shutter opener pawl 152 by the inserting force of the double-sided cartridge 131. This causes the opener belt 139 connected to the shutter opener hook 140 to move, sliding along the groove 137 against the force of the torsion spring installed inside the case body 132. As a result, the shutter 133 on the case body 132 moves in the direction that opens the opening 134.
When the double-sided cartridge 131 is still further inserted, the opening 134 is completely exposed, and the shutter opening operation is thus completed.
Upon completion of the shutter opening operation, the positioning pins provided inside the apparatus are inserted in the positioning holes 135 of the double-sided cartridge 131. At the same time, the reference posts inside the apparatus are made to abut against the reference faces 136 to hold the inserted double-cartridge 131 in position. The clamping face of the double-sided disk is then mounted on the turn table of the disk motor to complete the loading operation. In this case, the disk mounting distance (hereinafter referred to as L2), which is the distance from the reference faces 136 on the case body 132 to the clamping face of the double-sided disk, is 1.9 mm. L2 of the double-sided cartridge 131 is 0.5 mm shorter than L1 (2.4 mm) of the MO cartridge 101.
When the double-sided cartridge 131 is inserted upside down into the cartridge holder 151, the shutter opener pawl 152 formed on the opposite side engages on the shutter opener hook 140, and the same shutter opening operation as described above is performed. The shutter 133 is thus opened.
When the double-sided cartridge 131 is inserted with its rear end facing forward into the cartridge holder 151, the rear end corners of the case body 132 strike against the shutter opener pawls 152, and the double-sided cartridge 131 cannot be further inserted. Incorrect insertion of the disk is thus prevented.
As described above, the prior art loading mechanisms have been designed exclusively for either the MO cartridge or the double-sided cartridge. In the prior art, there have not been provided compatible loading mechanisms capable of loading both the MO cartridge 101 and the double-sided cartridge 131.
In recent years, in the field of optical disk technology, a demand has been increasing for compatible loading mechanisms that can load both the MO cartridge 101 and the double-sided cartridge 131.
However, there have been several problems as will be described below in the development of the compatible loading mechanism that can load both the MO cartridge 101 and the double-sided cartridge 131.
(1) The shutter opening system is different between the MO cartridge 101 and the double-sided cartridge 131. This has made it impossible to use either prior art loading mechanism as a compatible loading mechanism. More specifically, with the loading mechanism designed for the MO cartridge 101, the shutter 133 on the double-sided cartridge 131 cannot be opened. Furthermore, since the incorrect insertion prevention pawl 125 on the cartridge holder 121 strikes against a corner of the double-sided cartridge 131, the double-sided cartridge 131 cannot be inserted as far as to the prescribed position in the loading mechanism built for the MO cartridge 101.
On the other hand, with the loading mechanism designed for the double-sided cartridge 131, the shutter 104 on the MO cartridge 101 cannot be opened. Furthermore, since the shutter opener pawls 152 on the cartridge holder 151 strike against corners of the MO cartridge 101, the MO cartridge 101 cannot be inserted as far as to the prescribed position in the loading mechanism built for the double-sided cartridge 131.
(2) The thicknesses of the MO cartridge 101 and double-sided cartridge 131 are different by 1 mm. As a result, when the disk is mounted on the turn table, the disk mounting distance from the outer surface of the cartridge to the mounting surface of the disk is different by 0.5 mm between the MO cartridge 101 and the double-sided cartridge 131. This would require an adjusting mechanism to position the double-sided cartridge 131 0.5 mm higher than the MO cartridge 101, but neither the double-sided cartridge 131 nor the loading mechanism of the prior art has been equipped with such a mechanism to adjust the loading position of the inserted cartridge.

Disk reproducing apparatus and compatible cartridge used with the same

Matsushita Electric Industrial Co., Ltd.


An above-ground pool is made up of a plurality of posts, wherein each post is a blow-molded unit having a base portion and a top portion with a coping seat. A plurality of coping members also blow-molded are each telescopically received one end to the other at the coping seat of the top of each post, and a one-piece fastener engages the overlapping telescopic ends of the coping members to the top of the post. A bracket is provided at the base of the post, the bracket having a rail for receiving track segments wherein an elongated flexible metal wall is inserted. The top of the flexible wall is retained by the coping member against the post.

1. Field of the Invention
The present invention relates to an above ground swimming pool, and more particularly, to a swimming pool having a water impermeable liner, at least an upstanding panel surrounding the liner, and an improved coping structure with upstanding posts.
2. Description of the Prior Art
Present day above ground pools generally have posts and coping structures supporting a single endless panel. However, most such structures rely on nuts and bolts to connect the many posts and coping elements together. On a large pool, that is, an obround pool in the order of 40 feet, the number of posts and coping sections is considerable, and as a result, the number of nuts and bolts that must be utilized is considerable. The labor required for erecting such a pool is, therefore, substantial.
Since the posts and coping elements must form an enclosed loop, the elements forming it must be produced with precision. There can be very little tolerances when erecting a structure that might measure over 100 feet in terms of the loop being formed.
Examples are illustrated in U.S. Pat. Nos. 3,274,621, Diemond et al, 1966; 3,869,736, Valois et al, 1975; 4,413,361, Wolf et al, 1983; and 5,155,872, Aymes, 1992. Each one of these pools shows the necessity of precision in the fabrication of the posts and coping sections or upper rails and lower rails. Even assuming relatively low tolerances in the fabrication of swimming pool components, imprecise connections will still occur over the overall installation of the pool wall because of the accumulation of the tolerances over the relatively large dimensions of the loop being formed. These problems will occur at the installation phase in the field and must be overcome by sometimes damaging the last components being connected in order to get the parts to fit.
Another disadvantage that has been found with conventional above ground pool kits, as represented by the above patents, is the number of fasteners that must be manipulated in the field in order to erect the pool. Such manipulation of fasteners, such as nuts and bolts, requires an inordinate amount of labor at the site.


A polishing pad comprising a knitted fabric constituted by warp knitting or weft knitting, and a resin with which the knitted fabric is impregnated, and having a cross section cut in a surface direction of the knitted fabric, as a polishing surface.

In recent years, materials such as silicon carbide (SiC), gallium nitride (GaN), diamond (C), sapphire (Al2O3) and aluminum nitride (AlN), which are wide band-gap semiconductors, have attracted attention as next-generation power semiconductor element materials. For example, silicon carbide (SiC) has excellent physical property values such as a band gap 3 times and a breakdown electric field strength about 7 times those of silicon (Si) semiconductors, and is excellent in high-temperature operability and also small in size and high in energy-saving effect as compared with current silicon semiconductors. In addition, sapphire wafers are increasingly of importance in electronic equipment having optical elements, such as components for high-performance projectors, due to their chemical stability, optical characteristics (transparency), mechanical strength, thermal characteristics (heat conductivity), and the like. In order to really spread such next-generation power devices, an increase in the substrate diameter and the mass production of substrates are promoted, and the importance of substrate processing techniques is also increased along therewith.
In such a processing process, a cylindrical single crystal (ingot) for use in wafers is sliced and thus cut out into a disc shape, as in silicon (Si). Next, the surface of the disc-shaped single crystal obtained by slicing is flattened by, first, performing primary lapping (rough lapping) and secondary lapping (finishing lapping) by use of a lapping platen for rough removal of the roughness of the surface. Thereafter, primary polishing (rough polishing) and secondary polishing (finishing polishing) are performed for a further enhancement in the flatness of the surface of the disc-shaped single crystal obtained by slicing and for removal of fine scratches on the surface for mirror finishing.
Conventionally, a cloth for semiconductor wafer polishing, in which a felt-like fibrous sheet is impregnated with a thermoplastic polyurethane resin, an expanded polyurethane polishing pad, and the like have been used in processing of a common Si semiconductor wafer or the like (see, for example, Patent Literature 1). In addition, there is known, as lapping processing for a high-hardness material such as SiC much higher in hardness than Si, in particular, lapping processing where a metallic platen of copper, tin, and the like is used and the platen and a diamond abrasive grain are combined (hereinafter, also referred to as "diamond lapping".) (see, for example, Patent Literature 2).
Chemical mechanical polishing (CMP) is generally adopted as a specific polishing method for primary polishing (rough polishing) and secondary polishing (finishing polishing). As polishing pads for use in CMP, there are known, for example, a resin-impregnated non-woven fabric and an expanded polyurethane (see, for example, Patent Literature 3), and a polishing pad formed so that one end of each of a plurality of fabric members fixed by a resin is exposed on a polishing surface where an object to be processed is polished (see, for example, Patent Literature 4).

Polishing pad and method for producing the same, and method for producing polished product


An aqueous storage solution for the storage of red blood cells, comprising an aqueous solution and at least one lipid, wherein the at least one lipid is effective in suppressing hemolysis in red blood cells and wherein the at least one lipid is emulsified within the aqueous solution.

Red blood cells are often separated from whole blood and collected for later transfusion to a patient in need of red blood cells. For example, red blood cells (hereinafter "RBCs") may be administered to a patient suffering from a loss of blood due to trauma, as a post-chemotherapy treatment, or as part of a treatment of one or more blood-borne diseases, such as certain anemias and the like. Unless administered immediately after collection from a donor, RBCs may be stored for some period of time prior to transfusion. The storage period may be anywhere from a few days to several weeks.
Prolonged storage of RBCs may affect RBC function. In order for the RBCs to be suitable for transfusion to the recipient, RBCs should maintain adequate cell function and metabolism. For example, RBCs should maintain an adequate concentration of adenosine triphosphate (ATP) and 2,3-DPG. In addition, stored RBCs should have acceptably low levels of hemolysis. Typically, an acceptable level of hemolysis is below 1.0% (in, for example, the U.S.) and 0.8% (in Europe) after 42 days in storage.
Media for providing a storage environment for RBCs that will allow cell function and cell metabolism to be preserved and maintained have been developed and are commonly used. The media developed for RBCs may prolong the storage life of RBCs. Examples of storage media are Adsol and SAG-M, available from Fenwal, Inc., of Lake Zurich, Ill. The development and use of storage media and container materials that provide an optimal storage environment for red blood cells remain a topic of keen interest.

Medium and methods for the storage of red blood cells


An electric-powered cutting machine includes: an electric motor, a housing for the electric motor; a plunger driven by the electric motor to reciprocate; and a blade holding mechanism. The blade holding mechanism holds a blade at a tip end portion of the plunger. The blade holding mechanism includes: a blade receiving face including a groove, a swinging member and a pressing member. The groove is shaped substantially the same as an attachment portion of the blade. The swinging member has one and other ends and pivoted at a swing fulcrum. The one end has a blade pressing portion capable of being disposed to oppose to the groove. The other end elongates to separate from the plunger. The pressing member presses the one end toward the groove.

1. Field of the Invention
The present invention relates to a jigsaw type electric-powered cutting machine having a blade holding mechanism.
2. Background Art
A conventional electric-powered cutting machine will be described with reference to FIGS. 1 and 18, taking a jigsaw as an example.
As shown in FIG. 1, a jigsaw includes: a housing 2 which has a switch 4 and a handle 3, in which a base 5 that serves as a guiding member during a cutting operation is attached to a lower side, and which houses an electric motor 100 as is known in the art and that is schematically shown in FIG. 1; and a plunger 1 which reciprocates in the vertical directions in the figure by a turning force of the electric motor 100. In the illustrated jigsaw, the plunger 1 is covered by a cover 6 which is formed by a transparent member. An upper portion of the plunger 1 is reciprocatively held inside the housing 2, and a lower portion protrudes to the outside from the housing 2. A blade 7 is detachably held by the lower portion of the plunger 1.
As shown in FIG. 18, the conventional jigsaw has a configuration in which a locking screw 28 that presses against a flat face of the blade 7, and a support member 29 that supports a flat face of the blade 7 on the side opposite in the pressing direction are attached to the tip end of the plunger 1. When the blade 7 is inserted into the plunger 1, the blade 7 can be fixed to the plunger 1 by fastening the locking screw 28.
However, the above-mentioned configuration has the inconvenience that it is necessary to use a tool for operating the locking screw 28 during a work of replacing the blade 7. Apparently, the fastening force acting on the locking screw 28 is variously changed depending on the worker, thereby causing a problem in that, when the fastening force is excessively large, the blade 7 is deformed.
As a jigsaw for solving the problem, European Patent Nos. 722,802 and 855,239 disclose a configuration in which a work of replacing a blade can be conducted without using a tool or the like.


The technologies described herein are generally directed to facilitating operation of system that can include a processor and a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations. In embodiments, the operations can include receiving, from a source user equipment, a first request to communicate to a destination group of user equipment via a multi-cast connection. Further operations can include identifying respective service areas of ones of the destination group, comprising a service area of a destination user equipment of the destination group. In some embodiments, operations can include generating a second request to initiate the multi-cast connection, the second request comprising the destination group of user equipment with the respective service areas, wherein the respective service area of the destination user equipment is for selection, by second network equipment based on the service area, a gateway group of base station equipment.

Different network communication services have been developed over time to address the needs of different customers. The push to talk (PTT) service has different characteristics that can meet service demands for certain users with mission critical communications and fast setup requirements, e.g., first responders, utilities, and railways.
Because PTT service connections may require the system to establish connections with multiple devices simultaneously, problems can occur when different devices, in different locations, and with different capabilities, must all be combined in a PTT session.

Location aware assignment of resources for push to talk (PTT) communication systems in a fifth generation (5G) network or other next generation wireless communication system


The present invention pertains to a method for multicasting ATM cells. The method comprises the steps of reading a first ATM cell to which a first cell read pointer is pointing. Then there is the step of transmitting the first ATM cell out a first port to a first address. Next there is the step of determining whether the first ATM cell is to be transmitted out the first port to a second address. Next there is the step of reading a cell pointer pointing to a second ATM cell if the transmission of the first ATM cell out the first port to addresses is completed. The present invention pertains to a multicast system for an ATM network. The multicast system is comprised of a first ATM cell pointer mechanism associated with a first port. The multicast system also comprises at least a second ATM cell pointer mechanism associated with a second port. The multicast system is also comprised of at least a first ATM cell. The first ATM cell pointer mechanism and the second ATM cell pointer mechanism points to the first ATM cell. There is a first node having a first address and a node address pointer. The first ATM cell pointer mechanism points to the first node. There is a second node having a second address. The node address pointer of the first node points to the second node. The first and second nodes form a linked list of addresses.

ATM (asynchronous transfer mode) is used for communication purposes in integrated digital networks. Through these networks, ATM cells travel to desired destinations. Due to the complexity and demands on a network, there exists concerns involving traffic control in regard to cells in the network. Moreover, in multicast (i.e. the transmission of a single ATM cell to multiple destinations), considerations must be given to memory utilization in regard to the storage of a cell going to a multitude of locations. Ideally, as little memory as possible should be utilized to maintain the cell for all the different locations to which it will be sent. The present invention provides an efficient approach to providing a cell to a multiplicity of connections for multicast.
The multicast function can be limited to the act of causing an individual ATM cell to be transmitted by multiple output ports of an ATM switching system, or it may include causing an individual output port to transmit an individual ATM cell multiple times. In the former case, it is possible to restrict the use of connection addresses so that the instances of a multicast ATM cell transmitted at different output ports will all have the same address information (known as the VPI and VCI). In the latter case, it is necessary for each copy of a multicast ATM cell to have a different VPI and/or VCI to indicate that each copy of the cell should be sent to a different final destination. The prior art for performing multicast in an ATM switch using multiple VPI/VCIs is to create and store multiple copies of the cell at some point within the ATM switching system.
The present invention relates to an efficient method and apparatus for multicasting a cell while preferably using different VPI/VCIs for each instance of the transmission of that cell. The multiple transmissions of the cell can occur on the same output port or different output ports of an ATM switching system. The important innovation is that it eliminates the need to make multiple copies of an individual cell in order to transmit the cell using different VPI/VCIs.

Method and apparatus for multicast of ATM cells


The invention includes an architecture in which components associate their design time functionality independent of a design tool. The design time functionality includes code generators, compilers, parsers and editors. The architecture includes interfaces for components and designers to communicate. The architecture includes attributes in metadata that describe the functionality associated with the instance of a component.

Design tools are employed by developers at design time to create user applications that are executed at run time of the applications. Generally, software developers (e.g., individuals developing software applications) utilize design tools to create unique software applications. These applications often involve selecting "visual" components/objects such as buttons, menus, or other user interface elements to enable an end user to operate the application. The design tool facilitates application development by providing design time support to enable the developer to simulate the run time environment associated with the application. "Design time" refers to manipulating these components or objects during the development process. A designer is one aspect of a design tool that provides design time support for visually manipulating components, especially visual components such as forms and controls. Design time support for manipulating components (e.g., via the designer) historically has been built into the design tool and the development of such support is generally independent of component development. Thus, new versions of the design tool generally need to be created to support new features in the components.
Designers have typically been employed in many well-known development environments such as Visual Basic or Visual C++, for example. Designers have also been employed by software developers—this includes the ability for third parties to plug in custom designers to the design tool. One problem with conventional custom designers is that they generally are an all-or-nothing process. For example, a vendor who supplies development tool components cannot augment existing design-time support for a single component, but typically provides a custom designer to handle all components. Unfortunately, this makes creating a designer a daunting task due to the complexity and volume of supporting all existing components. Moreover, this can also lead to feature inconsistencies between designers.
Another problem associated with conventional designers is that they are monolithic requiring the developer to choose which designer to use—the component is not permitted to participate in selection of the designer; which can result in feature inconsistencies between designers.

This patent is subject to a terminal disclaimer.

Component based design time architecture


In an ion generating element, (i) an induction electrode and a heater electrode are provided away from each other on one surface of an insulating base material such that the induction electrode and the heater electrode are insulated from each other, (ii) a dielectric layer is provided on the surface of the insulating base material, and (iii) the dielectric layer has a length covering the insulating base material and the dielectric layer has openings above a ground terminal of the induction electrode and above a ground terminal and a power supply connection terminal of the heater electrode so that the terminals are exposed. As a result, it is possible to provide an ion generating element for generating ions along with creeping discharge, a charging device, and an image forming apparatus, each of which can be produced at low costs and prevent damages when unexpected troubles occur, and each of which is excellent in terms of safety.

Conventionally, in an image forming apparatus employing an electrophotographic method, a charging device employing a corona discharge method has been used (i) as a charging device for charging a photoreceptor, (ii) as a transfer device for electrostatically transferring a toner image formed on a photoreceptor or the like onto recording paper or the like, (iii) as a removing device for removing recording paper or the like that has electrostatic contact with a photoreceptor or the like, and the like devices.
Such a charging device employing a corona discharge method includes a shield case having an opening facing a charge receiving material, such as a photoreceptor, recording paper, or the like, and a line or saw-like form discharge electrode to be provided in a tensioned state in the shield case. As such a charging device, for example, a so-called corotron for uniformly charging a charge receiving material by generating corona discharge by applying a high voltage to the discharge electrode, or a so-called scorotron for uniformly charging a charge receiving material by applying an intended voltage to a grid electrode provided between the discharge electrode and the charge receiving material (see, for example, Patent Literature 1) is used.
Patent Literatures 2 and 3, for example, disclose such a corona-discharge-type charging device used as a pretransfer charging device for charging a toner image to be transferred to a transfer medium, such as an intermediate transfer member or recording paper, before the toner image is transferred. Even if an amount of charge in the toner image formed on an image bearing member is uneven, the techniques disclosed in Patent Literatures 2 and 3 makes a charge amount of the toner image uniform before its transfer. As a result, it is possible to restrain a decrease in flexibility of a transfer when the toner image is transferred and to stably transfer the toner image onto the transfer medium.
However, such conventional charging devices have a lot of problems. Firstly, such a charging device needs not only a discharge electrode but also a shield case, a grid electrode, and the like. Further, it is necessary to ensure a predetermined distance (10 mm) between the discharge electrode and a charge receiving material. As a result, a lot of space for the charging device to be placed in is required. Generally, a developing device, a first transfer device, and the like devices are provided around a first transfer section, and a photoreceptor, a second transfer device, and the like devices are provided before a second transfer section. Therefore, there is only a small space for a pretransfer charging device to be placed in. For this reason, the conventional corona-discharge-type charging device causes a difficulty in a layout of such constituent devices in an image forming apparatus.
Secondly, the conventional corona-discharge-type charging devices have a problem that a great amount of discharge products such as ozone (O3) and nitrogen oxide (NOx) are generated. Generation of a great amount of ozone causes problems, such as generation of ozone smell, adverse effects on a human body, and deterioration of components due to strong oxidation. Further, generation of nitrogen oxide causes a problem that the nitrogen oxide is attached to a photoreceptor as ammonium salt (ammonium nitrate) and causes a defective image, and the like problems. Especially, an organic photoreceptor (OPC), which is generally used, is easily affected by ozone or NOx and causes image defects such as white spots and image deletions.
In order to prevent these problems, in an intermediate-transfer-type color image forming apparatus having a plurality of transfer members, it is preferable that a pretransfer charging device be provided in an upstream of all the transfer members (a plurality of first transfer members, and a second transfer member). This is preferable from the viewpoint that a charge amount of a toner image becomes uniform before the toner image is transferred. However, from a practical standpoint, the providing of a pretransfer charging device in such a manner is difficult due to a problem of a generation amount of ozone and NOx.
Further, in recent years, for the purpose of decreasing ozone, a contact charging method using a conductive roller, a conductive blush, or the like has been employed in a charging device for charging a photoreceptor itself. However, it is difficult to charge the photoreceptor without making a toner image uneven by such a contact charging method. Accordingly, a charging device employing a non-contact corona discharge method is used as a pretransfer charging device. However, in a case where the conventional corona-discharge-type pretransfer charging device is provided in an image forming apparatus including a contact charging device, an ozoneless effect is not exhibited.
As a technique to reduce a generation amount of ozone, for example, Patent Literature 4 discloses the following charging device. That is, a charging device in Patent Literature 4 includes: multiple discharge electrodes aligned at an approximately predetermined pitch along an axial direction; a high-voltage power supply for applying to the multiple discharge electrodes a voltage of not less than a discharge-initiating voltage; a resistor provided between an output electrode of the high-voltage power supply and the multiple discharge electrodes; a grid electrode provided, close to the multiple discharge electrodes, between the multiple discharge electrodes and a charge receiving material; and a grid power supply for applying a grid voltage to the grid electrode. In the charging device, the multiple discharge electrodes and the grid electrode are provided so that a gap therebetween is not more than 4 mm, thereby reducing a discharge current so that the generation amount of ozone is reduced.
However, although the technique disclosed in Patent Literature 4 can reduce the generation amount of ozone by reducing the discharge current as such, the reduction amount of ozone is still insufficient and around 1.0 ppm of ozone generates. Further, there has been another problem of unstable discharge caused due to attachment of discharge products, toner, paper dusts, or the like to the discharge electrodes, abrasion/deterioration of the heads of the discharge electrodes, or the like factor. Further, it is difficult to clean such discharge products, toner, paper dusts, or the like attached to the discharge electrodes because of the shape of the discharge electrodes.
Besides, a gap between the discharge electrodes and the charge receiving material is so narrow that unevenness in charge in a longitudinal direction (in a direction along the pitches between the discharge electrodes) is easily caused due to the pitches between the multiple discharge electrodes. There is another considerable method in which pitches between discharge electrodes are formed small to prevent such unevenness in charge. However, this increases production costs because the number of discharge electrodes is increased.
In view of the problems of the conventional charging devices, Patent Literature 5, for example, discloses a charging device including an ion generating element (a creeping discharge element) that includes: a discharge electrode having pointed protrusions in an outer circumference thereof and an induction electrode, the electrodes being provided so as to sandwich a dielectric member therebetween. The ion generating element generates ions by applying a high alternating voltage between these electrodes (hereinafter, this charge method is referred to as a creeping discharge method).
The creeping discharge type charging device is small because the device does not include a shield case, a grid electrode, and the like. Further, since a discharge surface is flat, the charging device is easily cleaned and excellent in maintenance.
A discharging characteristic of the ion generating element (the creeping discharge element) tends to decline under a high humidity condition. In view of this problem, for example, Patent Literatures 6 and 7 disclose techniques for improving the discharging characteristic by providing an ion generating element with a heater member and heating the ion generating element to remove absorption moisture in a discharge region. Especially, Patent Literature 7 discloses a technique in which an induction electrode generates Joule heat while a power is being supplied to the induction electrode, so that the induction electrode also works as a heater. With the technique disclosed in Patent Literature 7, it is possible to make the ion generating element small and to reduce costs, in comparison with a technique in which a heater element is separately provided.

Ion generating element, charging device, and image forming apparatus


An ATM routing switch has a buffer circuit for holding cells located on queues at output ports, the buffer having a first reserve buffer capacity for cells of a first type requiring integrity of cell transmission and a first designation for use in determining a permitted path through the network, a second reserve buffer capacity for cells of the first type having a second designation for use in determining a different permitted path in the network and a third reserve buffer capacity for cells of a second type accepting some loss of cells in transmission, flow control circuitry operating to limit input of cells of either the first or second type if predetermined thresholds for the first, second or third buffer capacities are reached.

The invention relates to routing switches for the transmission of digital signals and to methods of switching digital signals through routing switches. The invention is particularly applicable to ATM switches and methods of operating ATM switch networks.
Data communications in digital form are commonly used for distribution of data between computers and in telecommunications for the transmission of voice signals. Distributed computing systems have used Local Area Networks (LANs) but the requirement to provide wider networks has led to the need for reliable telecommunications networks which can support computer data as well as traditional voice traffic. Existing telephone networks have been designed to transmit voice traffic around the globe and such systems have been optimised for low band width with low latency between sender and receiver although the traffic is relatively insensitive to noise and data errors. Local area networks which have been used for computer communication have generally operated over relatively short distances but require high band width for computer data and in this case the data is not necessarily sensitive to latency but must avoid data errors or omissions. To mix the two communication requirements in a signal network, Broadband Integrated Services Digital Network systems have been proposed and in particular Asynchronous Transfer Mode (ATM) systems have been proposed using small self-routing packets of digital signals.
It is an object of the present invention to provide improved routing switches together with improved methods of switching data packets through a network of routing switches and is particularly applicable to ATM switches and systems.
Reference in this specification to a switch for bi-directional transmission of digital signals means a switch such that when two are connected together each may output a digital signal to the other. Switch 1 may act as a source of digital signals sent to switch 2 acting as a destination while switch 2 may act as a source of digital signals sent to switch 1 acting as a destination. The reference to source and destination may each be intermediate in an extended network of switches.
The invention provides a routing switch for bi-directional transmission of digital signal cells of at least two types, a first type requiring integrity of cell transmission while accepting variable bit rate of transmission, and a second type accepting some loss of cells in transmission, which switch has a plurality of input ports for receiving input cells for transmission through the switch, a plurality of output ports for outputting output cells buffer circuitry selectively connectable to both said input and output ports for holding a plurality of cells of each type after receipt by an input port and prior to output by an output port, designation circuitry to provide for each input port, and cells input through each port, a respective designation selected from at least first and second designations for use in determining permitted paths in a network, said buffer circuitry providing a first reserved buffer capacity for cells of said first type having said first designation, a second reserved buffer capacity for cells of said first type having said second designation, a third reserved buffer capacity for cells of said second type, and control circuitry for determining whether each input cell is of said first or second type and whether cells of the first type are of the first or second designation, loading each input cell of said first type into said buffer and providing a flow control signal to limit input cells of said first type of either of the first or second designations if predetermined thresholds for said first and second buffer capacities are reached for cells of the first type of the first and second designations respectively, and loading each input cell of said second type into said buffer if the number of cells of said second type in said buffer has not reached a predetermined threshold for said third buffer capacity, or discarding input cells of said second type if said predetermined threshold for said third buffer capacity has been reached.
Preferably said control circuitry includes threshold store circuitry to indicate first, second and third threshold values for respective numbers of cells of said first and second types in said buffer circuitry, and counting circuitry to count the number of cells of each of said type held in said buffer circuitry, whereby said control circuitry operates to provide flow control signals when a count of cells of said first type of either designtion reaches the respective first or second threshold value and to discard cells of said second type when a count of cells of said second type reaches said predetermined threshold dependant on said third threshold value.
Preferably said buffer circuitry is partitioned to hold controlled numbers of cells for a plurality of categories of each of said first and second types, and said threshold store circuitry and counting circuitry each provide respective values for each of said categories.
Preferably said categories relate to respective different priorities for each of said first type of cell of the first designation, first type of cell of the second designation and second type of cell, and said threshold store circuitry and counting circuitry each provide respective values for each of said different priorities.
Preferably the control circuitry includes a store to indicate for each input cell whether the designation is the first or second designation.
Preferably said buffer circuitry is partitioned to provide limited overflow capacity in excess of said first and second threshold values for cells of said first type to accomodate further cells of said first type which are output from a source of cells of said first type prior to input of flow control signals by said source to indicate that said first or second threshold has been reached.
Preferably control bits are arranged to include a congestion indicator for each cell of said second type, said input circuitry being responsive to said congestion indicator to determine an offset value from a stored threshold for said second buffer capacity thereby indicating the said predetermined threshold at which a cell of said second type is discarded.
The invention includes a method of transmitting through a routing switch in a network, digital signal cells of at least two types, a first type requiring integrity of cell transmission while accepting variable bit rate of transmission, and a second type accepting some loss of cells in transmission, which method comprises receiving input cells at a plurality of input ports for transmission through the switch, outputting output cells from a plurality of output ports holding in buffer circuitry a plurality cells of each type after receipt by an input port and prior to output by an output port, designating each cell with a respective designation, selected from at least first and second designations, for use in determining permitted communication paths in the network, providing in said buffer circuitry a first reserved buffer capacity for cells of said first type having said first designation, a second reserved buffer capacity for cells of said first type having said second designation, and a third reserved buffer capacity for cells of said second type, determining whether each input cell is a first type in the first designation, a first type in the second designation, or second type, loading each input cell of said first type into said buffer and providing a flow control signal to limit input of cells of said first type of either the first or second designation if a respective threshold for said first or second buffer capacity is reached, and loading each input cell of said second type into said buffer if the number of cells of said second type in said buffer has not reached a predetermined threshold for said second buffer capacity, or discarding input cells of said second type if said predetermined threshold for said second buffer capacity has been reached.
Preferably the method includes providing first, second and third threshold values for respective numbers of cells of said first type of the first designation, first type of the second designation and second type, in said buffer circuitry, counting the number of cells of respective type and designation held in said buffer, providing flow control signals when a count of cells of said first type of either designation reaches said first or second threshold value and discarding cells of said second type when a count of cells of said second type reaches said third threshold value.
Preferably each of said first, second and third reserved buffer capacities are sub-divided to provide categories of different priority, a plurality of separate threshold values being provided for counts of each category.
Preferably cells held in said buffer form a plurality of queues at respective output ports, separate counts of queue length being maintained in addition to counts of numbers of cells held in the buffer, the generation of flow control signals and discarding of cells being responsive to both types of count.

ATM switch for routing different cell types


Paging and power consumption are managed in conjunction with providing local breakout in a wireless wide area network. In some aspects, if a packet destined for an access terminal is received at an access point that provides local breakout, the access point may inform the network so that the network will cause the access point to page the access terminal. Alternatively, in some aspects an access point that provides local breakout may maintain idle context of the access terminal, whereby the access point may autonomously page the access terminal (i.e., without involving the core network). In some aspects local breakout traffic is filtered at an access point to reduce the number of pages or packets sent to an access terminal. In some aspects an indication of a packet type is provided with a page message to enable an access terminal to determine whether to receive the packet. In some aspects a local link interface may be selectively disabled or enabled to limit traffic at an access terminal.

1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to facilitating efficient local access.
2. Introduction
Wireless communication systems are widely deployed to provide various types of communication (e.g., voice, data, multimedia services, etc.) to multiple users. As the demand for high-rate and multimedia data services rapidly grows, there lies a challenge to implement efficient and robust communication systems with enhanced performance.
To supplement conventional mobile phone network base stations, small-coverage base stations may be deployed (e.g., installed in a user's home) to provide more robust indoor wireless coverage to mobile access terminals. Such small-coverage base stations may be referred to as access point base stations, Home eNodeBs ("HeNBs"), or home femtos. Typically, such small-coverage base stations are connected to the Internet and the mobile operator's network via a DSL router or a cable modem.
In some cases, one or more local services may be deployed at the same location as a small-coverage base station. For example, a user may have a home network that supports a local computer, a local printer, a server, and other components. In such cases, it may be desirable to provide access to these local services via the small-coverage base station. For example, a user may wish to use his or her cell phone to access a local printer when the user is at home.
In general, an Internet-enabled access terminal may not be able to communicate with a device on a home network because this device is protected by a firewall and the network address translation ("NAT") within the home router and the access terminal appears as a node on the public Internet from the perspective of the home network. There are methods to enable limited access to some home devices by using port forwarding, however, this requires detailed technical knowledge about the devices, the associated applications and the home router equipment, which may be considered beyond the capabilities of a wireless access terminal user. Accordingly, a need exists for efficient and effective methods for accessing local services.

Paging and power management schemes for local network access


A transmit signal is spread by a plurality of spreading sections 103, 104, 105, and 106, using different spreading codes. A selection section 107 increases the number of spread signals to be output as the number of retransmissions increases. By this means, a retransmission signal spread by means of many spreading codes is code division multiplexed. As a result, retransmission signal error rate characteristics are improved on the receiving side by despreading this code division multiplexed signal using the same plurality of spreading codes as on the transmitting side, and selecting or combining the despreading results with the greatest correlation power thereamong. Also, since the degree of code multiplexing is increased proportionally as the number of retransmissions increases, retransmission signal error rate characteristics can be improved without lowering spectral efficiency unnecessarily.

Conventionally, in radio communication using the CDMA method, a transmit signal is spread and transmitted, and on the receiving side a received signal is despread using the same spreading code as on the transmitting side. By this means, in CDMA radio communication, signals directed to a plurality of users can be code division multiplexed and transmitted by preparing a plurality of mutually orthogonal spreading codes.
Also, in CDMA communication, when a transmission error is detected on the receiving side, the transmitting side is requested to retransmit the same signal, and thus the error rate characteristics of receive data are improved.
FIG. 1 shows the configuration of a conventional CDMA transmitting apparatus. CDMA transmitting apparatus 1 sends a modulated transmit signal to a spreading section 3 via a control section 2. The spread signal obtained by means of spreading section 3 is transmitted via a radio transmitting section (RF) 4 that performs radio transmission processing such as digital-analog conversion processing and signal amplification, and an antenna AN.
CDMA transmitting apparatus 1 also inputs a CDMA signal received by antenna AN to a despreading section 7 via a radio receiving section (RF) 6 that performs radio reception processing such as analog-digital conversion processing. The signal despread by despreading section 7 is output as a received signal, and is also sent to a retransmission request detection section 8. Retransmission request detection section 8 detects a retransmission request signal included in the received signal, and sends the detection result to control section 2.
Control section 2 is provided with a buffer, and if there is a retransmission request, the previously transmitted transmit signal stored in the buffer is output as a retransmission signal. Control section 2 also performs control of retransmission signal transmission timing and so forth.
However, with a conventional CDMA radio transmitting apparatus, particularly when channel fluctuations are slow, errors may occur consecutively even when a signal directed to a specific user is retransmitted. In this case, the problem of an excessive increase of the number of retransmissions arises. Since transmission delay increases as the number of retransmissions increases, the major problem of decreased transmission efficiency occurs. There is thus a method whereby retransmissions are discontinued when a given time is reached, but in this case a new problem arises of degradation of error rate characteristics.

Code division multiple access transmitting apparatus having plural spreading sections that perform spreading processing separately for a retransmission signal using different spreading codes


The gene for Streptococcus pyogenes DNase B has been cloned and vectors incorporating the cloned DNA have been used to transform Escherichia coli, allowing efficient and rapid production of the DNase in E. coli without the necessity of growing large quantities of S. pyogenes. The enzyme can be produced with a leader peptide at its amino terminus. An improved method for the purification of naturally occurring S. pyogenes DNase B enzyme is also provided. The DNase B enzyme produced, either by purification of naturally occurring enzyme or by recombinant DNA techniques, can be used to generate antibodies and can also be used in immunochemical assays to detect the presence of anti-DNase B antibodies in serum as a marker of infection by S. pyogenes.

This invention is directed to recombinant DNase B derived from the pathogenic bacterium Streptococcus pyogenes, methods for its production, and methods for its use.
Despite advances in the prevention and treatment of bacterial infection, a number of bacterial pathogens remain serious problems in medical practice and continue to cause severe, even fatal disease. One of these pathogens is S. pyogenes. Among the diseases caused by S. pyogenes are streptococcal pharyngitis ("strep throat"), scarlet fever, and their suppurative complications, including cervical adenitis, otitis media, mastoiditis, peritonsillar abscesses, meningitis, pneumonitis, pneumonia, puerperal sepsis, cellulitis of the skin, impetigo, lymphangitis, erysipelas, acute glomerulonephritis, and rheumatic fever.
Such infections often occur in hospitals (nosocomial infection), particularly in patients whose normal immune system functioning is suppressed. The latter category includes patients with AIDS, patients taking immunosuppressive drugs for cancer or to prevent transplant rejection, and patients having poor circulation, e.g., patients with diabetes.
Because these diseases require rapid and effective treatment to eradicate the suppurative lesions and prevent sequelae caused by immunological reactions to persisting suppurative lesions, prompt diagnosis of the presence of S. pyogenes is essential in patients in whom such infections are suspected. Failure to diagnose S. pyogenes promptly can greatly complicate treatment or even make it impossible.
Although detection methods for S. pyogenes are currently available, these methods have defects, particularly in clinical applications.
Among the methods of detection of S. pyogenes is the detection of the presence of antibodies against DNase B, a DNA-degrading enzyme produced by S. pyogenes. This enzyme, which is excreted from S. pyogenes during infection, initiates development of substantial titers of antibody in patients who go on to develop acute rheumatic fever and acute glomerulonephritis.
Although other serum-based diagnostic tests for these rheumatic fever and glomerulonephritis are available, including the detection of antibodies to streptolysin O, and to hyaluronidase, assays for anti-DNase B antibodies offer certain advantages, because DNase B is found among nearly all strains of group A beta-hemolytic streptococci, and because high DNase B titers are found in patients with infections of the skin and pharynx.
Although a number of commercially-available tests exist for the assay of anti-DNase B antibody, these tests have defects. As indicated above, an improved test is greatly needed.
The commercially-available tests fall into three categories: (1) a DNase B inhibition-based assay using the ability of the antibody to inhibit enzymatic activity; (2) a latex agglutination assay for antibody against a variety of S. pyogenes antigens; and (3) a turbidimetric inhibition assay. ELISA assays have also been used in the research laboratory, but, as detailed below, they have not yet proven suitable for routine clinical application.
The DNase B inhibition assay is very slow, and typically requires about 4-8 hours to perform. Thus, in situations in which confirmation of anti-DNase B antibody is required rapidly so the treatment can be started as soon as possible should the presence of S. pyogenes be confirmed, the enzyme inhibition assay is not particularly useful.
The latex agglutination assay is designed to detect antibodies to five S. pyogenes antigens. However, test results indicate poor agreement between the latex agglutination assay and a specific anti-DNase B tests. In one study, G. C. Klein & W. L. Jones, "Comparison of the Streptozyme Test with the Antistreptolysin O, Antideoxyribonuclease B, and Antihyaluronidase Tests," App. Microbiol. 21:257-259 (1971), 12 out of 80 patients that tested negatively in the latex agglutination assay were, in fact, positive for anti-DNase B antibody. This high level of false negative results means that the test is undesirable for clinical use.
The turbidimetric inhibition assay depends on the inhibition of agglutination of latex particles coated with anti-DNase B antibody by a limiting quantity of a crude preparation of DNase B in the presence of serum containing anti-DNase B antibody, which competes for the antibody on the latex particles. This assay, which is described in U.S. Pat. No. 5,055,395, incorporated herein by this reference, is relatively insensitive. Therefore, it is not suitable for use in the early stages of S. pyogenes infection, and it is precisely this period when accurate detection of the anti-DNase B antibody is most important. Additionally, the reagents used in the turbidimetric inhibition assay are difficult to manufacture.
ELISA-based assays for anti-DNase B antibody are reported in M. A. Gerber et al., "Enzyme-Linked Immunosorbent Assay of Antibodies in Human Sera to Streptococcal DNase B," J. Lab. Clin. Med. 95:258-265 (1980). Although these assays have proven effective as research tools, their scale-up for commercial use, particularly in clinical practice, has been impractical. This is because such scale-up would require production and purification of the DNase B enzyme of Streptococcus pyogenes, which is, as detailed above, a serious pathogen. Not only would extremely costly containment methods be required for growth of this pathogenic bacterium in the quantity required to produce sufficient enzyme for commercialization of the ELISA assay, the media required for the growth of S. pyogenes is very complex and expensive. These concerns have seriously hampered development of a commercial version of the ELISA assay for anti-DNase B antibody.
Therefore, there exists a need for an improved, rapid, and specific assay for anti-DNase B antibody. Preferably, such an assay would be usable by a physician in his office and would require minimal equipment. This is because patients with diseases such as strep throat or scarlet fever typically see their family physician prior to hospitalization, and accurate diagnosis of S. pyogenes infection at that point would be preferable to a subsequent diagnosis made only when the patient has been hospitalized.
The development of such an improved assay is dependent on the availability of large quantities of DNase B enzyme itself. Therefore, there is also a need for a method for the production of S. pyogenes DNase B enzyme using a procedure that can be scaled up to produce commercial quantities of the enzyme without requiring complex, unwieldy, and expensive containment measures.


Techniques for representing extensible markup language (XML) in an executable format are presented. An XML document is parsed into its components and content. The components and content are packaged as an executable. Some portions of the executable include authentication logic or policy logic that is subsequently enforced when the executable is processed. The executable is subsequently distributed to recipient machines. The machines process the executable and produce memory loaded versions of the components and content representing the XML document on the machines. The memory loaded versions of the components and content include conditionally added authentication logic or policy logic.

Increasingly data is being represented in a platform-independent format that it is devoid of presentation specific and environmental specific limitations. The most popular data format for this data encoding is Extensible Markup Language (XML).
With XML the content of a document is divorced from its presentation specifics. Any desired presentation formatting is applied by a recipient of the XML document using an Extensible Style Sheet's Language (XSL) template and/or the recipient processing an Extensible Style Sheet Transformation (XSLT) application.
To effectively use an XML document, a recipient's XML parser breaks the received XML document into its hierarchical components into memory as a tree structure. This internal tree structure is often referred to as a Document Object Model (DOM). Once an XML document is in a DOM format within memory, the recipient applies any XSL templates and/or XSLT applications to render the content of the document into a specific presentation within the recipient's environment.
One problem associated with this process is that the initial parsing to acquire the DOM for the XML content can be processor and memory intensive on the recipient's device. That is, the XML parser is not very efficient in processing the XML text (XML content) into the tree structure associated with the DOM representation.
Another problem is that any desired processing to enforce policy or perform authentication is typically not capable of being represented in the XML document; rather, each recipient uses its own XSLT application to apply policy or to perform authentication against or for the XML content.
Thus, what is needed is a mechanism that allows for more efficient and flexible XML document representations and XML content processing.

Representing extensible markup language (XML) as an executable having conditional authentication or policy logic