Described herein are systems and methods to manage blacklists and duplicate addresses in software defined networks (SDNs). In one implementation, a method includes, in a control plane and data plane of an SDN environment, obtaining a blacklist for a logical port in the SDN environment. The method further includes deleting realized address bindings in a realized address list for the logical port that match the one or more address bindings in the blacklist and preventing subsequent address bindings that match the one or more address bindings in the blacklist from being added to the realized address list.

Software defined networks include logical entities that provide various networking operations for computing elements, such as virtual machines and containers. The networking operations may include routing operations, switching operations, firewall operations, or some other networking operations. To implement the networking operations, a networking controller may be required to distribute software defined networking configuration data to various computing elements that host the logical entities of the software defined networks. These computing elements may comprise host computing systems for virtual nodes, such as containers or virtual machines, may comprise routing or switching elements, or may comprise some other computing element.
In some implementations, as the number of logical devices and logical ports are increased, it can become difficult and cumbersome to manage address bindings for the various logical elements. In particular, administrators may encounter obstacles in efficiently and effectively managing blacklists and addressing duplication across the software defined networking environment.
Overview
The technology disclosed herein manages blacklists and duplicate addresses in software defined networks. In one implementation, a method of blacklisting addresses in a Software Defined Networking (SDN) environment includes, in a management plane of the SDN environment, configuring one or more address bindings in a blacklist for a logical port in the SDN environment. The method further includes passing the blacklist from the management plane to a data plane and a control plane for the logical port. The method further provides, in the data plane and the control plane, deleting realized address bindings in a realized address list for the logical port that match the one or more address bindings in the blacklist and preventing subsequent address bindings that match the one or more address bindings in the blacklist from being added to the realized address list.

Management of blacklists and duplicate addresses in software defined networks


An apparatus for and a method of remote echo cancellation in a packet based telephony system. Echo cancellation algorithms normally performed on the local end of a connection, are performed instead by the remote end of the connection. Alternatively, the echo cancellation algorithms are performed for both the local and remote ends of a connection on a remote device. In the former case, the remote endpoint estimates the echo function of the local endpoint using audio and timing synchronization data corresponding to the actual audio played at the local endpoint. Using this information, the remote endpoint is able to accurately perform echo cancellation.

The present invention relates generally to voice over IP networks and more particularly relates to an apparatus and method of performing remote echo cancellation for the local endpoint of a connection.
Currently, there is a growing trend to converge voice and data networks so that both utilize the same network infrastructure. The currently available systems that combine voice and data have limited applications and scope. An example is Automatic Call Distribution (ACD), which permits service agents in call centers to access customer files in conjunction with incoming telephone calls. ACD centers, however, remain costly and difficult to deploy, requiring custom systems integration in most cases. Another example is the voice logging/auditing system used by emergency call centers (e.g., 911) and financial institutions. Deployment has been limited due to the limited scalability of the system since voice is on one network and data is on another, both tied together by awkward database linkages.
The aim of IP telephony is to provision voice over IP based networks in both the local area network (LAN) and the wide area network (WAN). Currently, voice and data generally flow over separate networks, the goal is to transmit them both over a single medium and on a single network.
A block diagram illustrating example separate prior art data and voice networks is shown in FIG. 1. The LAN portion, generally referenced 10, comprises the LAN cabling infrastructure, routers, switches and gateways 12 and one or more network devices connected to the LAN. Examples of typical network devices include servers 14, workstations 16 and printers (not shown). The voice portion, generally referenced 20, has at its core a private branch exchange (PBX) 24 which comprises one or more trunk line interfaces and one or more telephone and/or facsimile extension interfaces. The PBX is connected to the public switched telephone network (PSTN) 22 via one or more trunk lines 28, e.g., analog T1, E1, T3, ISDN, etc. A plurality of user telephones 26 and one or more facsimile machines 27 are also connected directly to the PBX via phone line extensions 29.
The paradigm currently in wide spread use consists of circuit switched fabric 20 for voice networks and a completely separate LAN infrastructure 10 for data. Most enterprises today use proprietary PBX equipment for voice traffic.
An increasingly common IP telephony paradigm consists of telephone and data tightly coupled on IP packet based, switched, multimedia networks where voice and data share a common transport mechanism. It is expected that this paradigm will spur the development of a wealth of new applications that take advantage of the simultaneous delivery of voice and data over a single unified fabric.
A block diagram illustrating a voice over an IP network where voice and data share a common infrastructure is shown in FIG. 2. The IP telephony system, generally referenced 30, comprises, a LAN infrastructure represented by an Ethernet switch 32, a router, one or more telephones 36, workstations 34, a gateway 42, a gatekeeper 46, a PBX 33 with a LAN interface port and a Layer 3 switch 38. The key components of an IP telephony system 30 are the modified desktop, gatekeeper and gateway entities. For the desktop, users may have an Ethernet phone 36 that plugs into an Ethernet RJ-45 jack or a handset or headset 35 that plugs into a PC 37.
Today, all LAN based telephony systems need to connect to the PSTN 44. The gateway is the entity that is specifically designed to convert voice from the IP domain to the PSTN domain. The gatekeeper is primarily the IP telephony equivalent of the PBX in the PSTN world.
Typically, the IP telephony traffic is supported by a packet-based infrastructure such as an Ethernet network but a circuit-based infrastructure can be used as well with some provisions (e.g., ATM LAN emulation on ATM networks). Telephony calls traversing the intranet may pass through a Layer 3 switch 38 or a router (not shown) connecting a corporate intranet 40. The Layer 3 switch and the router should support Quality of Service (QoS) features such as IEEE 802.1p and 802.1Q and Resource Reservation Protocol (RSVP).
The International Telecommunications Union (ITU-T) Telecommunications Standardization Sector has issued a number of standards related to telecommunications. The Series H standards deals with audiovisual and multimedia systems and describes standards for systems and terminal equipment for audiovisual services. The H.323 standard is an umbrella standard that covers various audio and video encoding standards. Related standards include H.225.0 that covers media stream packetization and call signaling protocols and H.245 that covers audio and video capability exchange, management of logical channels and transport of control and indication signals. Details describing these standards can be found in ITU-T Recommendation H.323 (Draft 4 August 1999), ITU-T Recommendation H.225.0 (February 1998) and ITU-T Recommendation H.245 (Jun. 3, 1999).
A block diagram illustrating example prior art H.323 compliant terminal equipment is shown in FIG. 3. The H.323 terminal 50 comprises a video codec 52, audio codec 54, system control 56 and H.225.0 layer 64. The system control comprises H.245 control 58, call control 60 and Registration, Admission and Status (RAS) control 62.
Attached video equipment 66 includes any type of video equipment, such as cameras and monitors including their control and selection, and various video processing equipment. Attached audio equipment 70 includes devices such as those providing voice activation sensing, microphones, loudspeakers, telephone instruments and microphone mixers. Data applications and associated user interfaces 72 such as those that use the T.120 real time audiographics conferencing standard or other data services over the data channel. The attached system control and user interface 74 provides the human user interface for system control. The network interface 68 provides the interface to the IP based network.
The video codec 52 functions to encode video signals from the video source (e.g., video camera) for transmission over the network and to decode the received video data for output to a video display. If a terminal incorporates video communications, it must be capable of encoding and decoding video information in accordance with H.261. A terminal may also optionally support encoding and decoding video in accordance with other recommendations such as H.263.
The audio codec 54 functions to encode audio signals from the audio source (e.g., (microphone) for transmission over the network and to decode the received audio data for output to a loudspeaker. All H.323 audio terminals must be capable of encoding and decoding speech in accordance with G.711 including both A-law and xcexc-law encoding. Other types of audio that may be supported include G.722, G.723, G.728 and G.729.
The data channel supports telematic application such as electronic whiteboards, still image transfer, file exchange, database access, real time audiographics conferencing (T.120), etc. The system control unit 56 provides services as defined in the H.245 and H.225.0 standards. For example, the system control unit provides signaling for proper operation of the H.323 terminal, call control, capability exchange, signaling of commands and indications and messaging to describe the content of logical channels. The H.225.0 Layer 64 is operative to format the transmitted video, audio, data and control streams into messages for output to the network interface. It also functions to retrieve the received video, audio, data and control steams from messages received from the network interface 68.
The gateway functions to convert voice from the IP domain to the PSTN domain. In particular, it converts IP packetized voice to a format that can be accepted by the PSTN. The actual format depends of the type of media and protocol used for connecting to the PSTN (e.g., T1, E1, ISDN BRI, ISDN PRI, analog lines, etc.). The gateway provides the appropriate translation between different video, audio and data transmission formats and between different communications procedures and medias.
Note that since the digitization format for voice on the IP packet network is often diferent than on the PSTN, the gateway needs to provide this type of conversion which is known as transcoding. Note also that gateway also function to pass singaling information such as dial tone, busy tone etc. Typical connections supported by the gateway include analog, T1, E1, ISDN, frame relay and ATM at OC-3and higher rates. Additional function performed by the gateway include call setup and clearing on both the network side and the PSTN side. The gateway may be omitted if communication with the PSTN is not required.
The gatekeeper functions to provide call control services, address translation services, call routing services, call authorization services, billing, bandwidth management and telephony supplementary services like call forwarding and call transfer to terminal endpoints on the network. It is primarily designed to be the IP telephony equivalent of the PBX. Logical endpoints register themselves with the gatekeeper before attempting to bring up a session. The gatekeeper may deny a request to bring up a session or may grant the request at a reduced data rate. This is particularly relevant to video connections that typically consume huge amounts of bandwidth for a high quality connection.
Call control signaling is optional as the gatekeeper may choose to complete the call signaling with the H.323 endpoints and process the call signaling or it may direct the endpoints to connect to the call signaling channel directly, the gatekeeper thus avoiding handling the H.225.0 call control signals.
Through the use of H.225.0 signaling, the gatekeeper may reject calls from a terminal due to authorization failure. The reasons for rejection may include restricted access to or from particular terminals or gateways, or restricted access during certain time periods.
Bandwidth management entails controlling the number of H.323 terminals that are allowed to simultaneously access the network. Via H.225.0 signaling, the gatekeeper may reject calls from a terminal due to bandwidth limitations. This may occur if the gatekeeper determines that there is insufficient bandwidth available on the network to support the call.
The call management function performed by the gatekeeper includes maintaining a list of currently active H.323 calls. This information is used to indicate that a terminal is busy and to provide information for the bandwidth management function.
The gatekeeper also provides address translation whereby an alias address is translated to a Transport Address. This is performed using a translation table that is updated using Registration messages, for example.
The H.225.0 standard dictates the usage of the Real-time Transport Protocol (RTP) which is defined by the IETF in RFC 1889 for conveying data between the call endpoints and for monitoring the network congestion. The RTP protocol defines the RTP packet structure that includes two parts: the RTP packet header part and the RTP packet payload part. The RTP packet header includes several fields. Among those fields, are the payload type identification field, the sequence numbering field and the time stamping field. Typically, applications encapsulate RTP in a UDP packet. UDP/IP is an unreliable transport mechanism and therefore there is no guarantee that the RTP packet would reach its destination. RTP may, however, be used with other suitable underlying network or transport protocols.
RTP does not itself provide any mechanism to ensure timely delivery or other QoS guarantees, but relies on lower layer services to do so. It also does not guarantee delivery, nor does it assume that the underlying network is reliable and delivers packets in sequence. RTP includes sequence numbers and timestamps in the packet to allow the receiver to reconstruct the sender""s packet sequence and timing.
RTP is intended to be flexible so as to provide the information required by a particular application. Unlike conventional protocols in which additional functions may be accommodated by making the protocol more general or by adding an option mechanism that requires parsing, RTP can he tailored through modifications and/or additions to the headers.
The RTP Control Protocol (RTCP) functions to periodically transmit control packets to all participants in a session. The primary function of RTCP is to provide feedback on the quality of the data distribution that is useful for monitoring network congestion. The RTCP protocol is designed to monitor the quality of service and to convey information about the participants in an on-going session. RTCP also carries a transport level identifier for an RTP source called the canonical name or CNAME. Receivers requite the CNAME to associate multiple data streams from a given participant in a set of related RTP sessions. The RTCP protocol can also be used to convey session control information such as participant identification. Each RTCP packet begins with a fixed header followed by structured elements of variable length. Note that the signaling/control information carried in the RTCP packets is transmitted using the TCP/IP reliable protocol.
Also under the H.323 protocol umbrella are a number of standards for voice codecs including for example, G.711, G.729, G.729.1 and G.723.1.
Call signaling encompasses the messages and procedures used to establish a call, request changes in bandwidth of the call, get status of the endpoints in the call and disconnect the call. Call signaling uses messages defined in the H.225.0 standard. In particular, the RAS signaling function uses H.225.0 messages to perform registration, admissions, bandwidth changes, status and disengage procedures between endpoints and Gatekeepers. The RAS Signaling Channel is independent from the Call Signaling Channel and the H.245 Control Channel.
Each H.323 entity has at least one network address that uniquely identifies the H.323 entity on the network. For each network address, each H.323 entity may have several TSAP identifiers that enable the multiplexing or several channels sharing the same network address. Endpoints have one well-known TSAP identifier known as the Call Signaling Channel TSAP Identifier. In addition, Gatekeepers also have one well-known TSAP identifier defined as the RAS Channel TSAP Identifier, and one well-known multicast address defined as the Discovery Multicast Address. Endpoints and H.323 entities use dynamic TSAP Identifiers for the H.245 Control Channel, Audio Channels, Video Channels, and Data Channels while the Gatekeeper uses a dynamic TSAP Identifier for Call Signaling Channels.
Further, an endpoint may have one or more alias addresses associated with it. An alias address represents the endpoint and provides an alternate method of addressing the endpoint. It is important to note that an endpoint may have more than one alias address that translates to the same TSAP. The alias may comprise, for example, private telephone numbers, E.164 numbers, any alphanumeric string that may represent a name, e-mail address, etc. In addition, the alias may comprise a MAC address, IP address, ATM address, access token, DNS address, TSAP as IP address concatenated with a port number or name alias. Note that alias addresses are unique within a zone and that gatekeepers do not have alias addresses.
When there is a Gatekeeper in the network, the calling endpoint addresses the called endpoint by its Call Signaling Channel Transport Address or by its alias address. The Gatekeeper translates the latter into a Call Signaling Channel Transport Address.
An endpoint joins a zone via the registration process whereby it informs the Gatekeeper of its Transport Addresses and one or more associated alias addresses. Note that registration must take place before any calls are attempted. When endpoints are powered up, they look on the network for the Gatekeeper and once found, they register their TSAP and one or more aliases with therewith.
In LAN Telephony applications, the voice samples generated are packed within RTP packets that are then encapsulated within UDP/IP packets. The UDP packets that travel over an IP network may, however, be delayed, dropped or arrive out or order from their original transmission sequence depending on the degree of network congestion. Therefore, the frequency in which the packets arrive at the receive side is not constant.
In order to combat the variable delay problems, many devices implement a jitter buffet on the receive side. If packets are only delayed within the network, arriving at the receiver before the jitter buffer underflows, the receive side will hear the sound as it was original transmitted by the local endpoint. If, however, packets are dropped or packets are delayed too much and the jitter buffer underflows (i.e. becomes empty), the receiving device either (1) replays the last packet received or (2) it injects a silence.
Thus, in the event packets are dropped or are delayed excessively causing jitter buffer underflow, the sound that is played on the receive side is not the original sound that was transmitted.
As in most voice communication devices, e.g., telephone, etc., a portion of the voice that is played on the receive side is returned to the transmitting side as an undesirable echo by the transmitter portion of the device. There are several sources that cause this undesirable phenomenon. The first source is the acoustic echo made up of sound waves produced by the loudspeaker that are reflected by the room walls and other objects in the room towards the microphone that records them. Another source of echo is the magnetic flux effects of the hybrid circuit in the telephone set and at the Central Office (CO). A 4 to 2 line hybrid is located in the telephone set to merge both transmit and receive directions onto a single copper pair wire. A corresponding 2 to 4 line hybrid is located at the CO to convert the single line into separate transmit and receive circuits. The magnetic flux of the receive circuitry passes through the transmit circuit coils thus causing the transmit circuit to record what is played on the receive circuit.
Some echo or feedback is desirable, however, such as when speaking on the telephone and the speaker heats her/his own voice through the handset. In this case, a small portion of the voice from the microphone is intentionally fed back to the speaker element. This intentional echo is injected locally from the microphone towards the speaker and is never sent lo the remote side.
In communication systems adapted to transfer voice, the quality of the voice is sensitive, among other things, to the round trip delay. If the round trip delay is less then 300 ms, the returned echo will not be bothersome to users. If, however, the round trip delay is greater than approximately 300 ms, the returned echo becomes noticeable to most users. In the IP telephony world there exist several sources that contribute to the round trip delay. First, each end point collects several samples until it fills an RTP packet, thus delaying the first samples. The packet is then encapsulated within a UDP/IP/Ethernet packet (und is sent over the network. The packet traverses through the network passing through one or more routers and switches, where each hop adds to the overall delay. Finally, it arrives at the remote endpoint where it is delayed in a jitter buffer until it is played. At the remote endpoint, the played sample returns as an echo with the voice that is now recorded. The round trip delay is twice the time it took from the time the sample is recorded until it is played at the remote end.
Each endpoint must, therefore, be adapted to remove this echo if the round trip delay is more then 300 ms. The echo is always removed locally whereby each end of a connection is adapted to subtract the echo from the signal it transmits Lo the other side. In the IP telephony world the echo must be removed locally, since the echo is generated from the sound that is played which may be different from the sound that was originally transmitted. Thus, each endpoint must incorporate the necessary means for removing the echo.
Typically, an endptoint incorporates one or more specialized powerful processors such as digital signal processors (DSPs) to perform the echo cancellation. A disadvantage is that these processors and their associated circuitry are costly thus increasing the resultant cost and design complexity of any device incorporating them.
The present invention provides an apparatus for and a method of remote echo cancellation in packet based telephony systems. Using the present invention, one or both endpoints in a connection do not need to perform the complex and processor intensive task of echo cancellalion. Utilizing the present invention the remote end of a connection is adapted to perform echo cancellation algorithms for both itself and the endpoint at the other end of the connection. Alternatively, a third party device serving as a transit point for the RTP packet stream can be adapted to perform the method of the present invention for one or both endpoints.
The remote endpoint (or third party device) is provided knowledge of the actual audio played on the other side (or local side) and a means for synchronizing this audio stream to the audio stream that was concurrently recorded by the local endpoint. The remote endpoint must know what was played at the local endpoint in order to accurately cancel the echo from the audio samples generated and sent by the local endpoint. The remote endpoint must estimate the echo function on the local endpoint.
To perform echo cancellation, the remote endpoint needs to know, for each data sample recorded by the local endpoint, what data sample from the remote endpoint the local endpoint played at that moment in time. In addition, the remote endpoint needs to know the several data samples that preceded the recorded data sample. The remote endpoint (or third party) is provided knowledge of the audio played on the local end of the connection via information transmitted in the header and header extension portions of the RTP packets and via the knowledge or the number of samples in the payload part of the RTP packet. There are two methods by which the local endpoint can notify the remote endpoint about which remote endpoint samples were played when the samples in the data packet were recorded: the first method is by using timestamps and the second method is by using RTP packet sequence numbers and offset pointers into the RTP packets.
In the timestamp method, the other endpoint (i.e. the local endpoint) is adapted to include the timestamp of the packet of audio that is played, with the packet of data samples sent to the remote endpoint. Thus, two timestamps are sent in the RTP packet including (1) a first timestamp of the data samples generated by the local endpoint (this timestamp value is taken when the first sample in the packet is taken) and (2) a second timestamp of the packet received from the remote endpoint and played at a point in time when the first sample of the local endpoint packet is generated.
The local endpoint is operative to track the timestamp of the data samples received encapsulated in RTP packets sent from the remote endpoint. These data samples are subsequently played by the local endpoint through its associated speaker. The data samples generated by the local endpoint are timestamped and placed in RTP packets. In addition, the timestamp of the data samples played by the local endpoint at that moment in time is also placed in the extension portion of the header of the RTP packet sent to the remote endpoint.
If the last packet received was replayed, an indication is placed in the header. extension of the packet that comprises the timestamp of the most recently received RTP packet. If a silence is played, a zero is placed in the header extension. The completed RTP packet is then sent to the remote endpoint.
The timestamp from the header extension portion of the RTP packets received from the local endpoint is extracted. A timestamp equal to zero indicates that a silence was played at the local endpoint. If the timestamp extracted is equal to the previous timestamp sent by the local endpoint, then this indicates that the local endpoint replayed the last received packet.
Otherwise, the timestamp extracted from the header extension is the timestamp of the packet that was played on the local endpoint at a point in time corresponding to the timestamp of the data samples sent in the packet. Assuming the remote endpoint has an estimate of the echo function on the local endpoint, the remote endpoint perform echo cancellation using its knowledge of the data samples played on the local endpoint. The remote endpoint is adapted maintain a copy of the most recent packets sent to the local endpoint. Since it maintains a copy of the packets, only the timestamp need be sent from the local endpoint to uniquely identify a particular packet.
The sequence method is similar to the timestamp method with the difference being that endpoint A places the sequence number and the offset within the packet that was received from endpoint B and played at the time when the first sample of the RTP packet being built is taken. This is in place of sending a timestamp.
There is therefore provided in accordance with the present invention a method of performing echo cancellation on a remote device in a packet telephony system, the system supporting a connection between a first endpoint and a second endpoint, the method comprising the steps of tracking a second timestamp of data samples originating from the second endpoint that are played by the first endpoint, generating data samples on the first endpoint, sending to the remote device packets containing data samples generated by the first endpoint, a first timestamp corresponding thereto and the second timestamp of data samples from the second endpoint played by the first endpoint at that moment in time, placing an indication in the packet of data samples sent to the remote device, the indication operative to specify whether a packet, several packets, several sequential samples from the same packet or several sequential samples from different packets received by the first endpoint were replayed or that a silence was played, tracking the number of data samples in the packets received by the remote device and reconstructing on the remote device the signal played on the first endpoint using the first timestamp, the second timestamp, the number of samples in the packet, and the indication information and performing echo cancellation therewith.
There is also provided in accordance with the present invention an apparatus for performing echo cancellation on a remote device in a packet telephony system, the system supporting a connection between a first endpoint and a second endpoint comprising means for tracking a second timestamp of data samples originating from the second endpoint that are played by the first endpoint, means for generating data samples on the first endpoint, means for sending to the remote device packets containing data samples generated by the first endpoint, a first timestamp corresponding thereto and the second timestamp of data samples from the second endpoint played by the first endpoint at that moment in time, means for placing an indication in the packet of data samples sent to the remote device, the indication operative to specify whether a packet, several packets, several sequential samples from the same packet or several sequential samples from different packets received by the first endpoint were replayed or that a silence was played, means for tracking the number of data samples in the packets received by the remote device and means for reconstructing on the remote device the signal played on the first endpoint using the first timestamp, the second timestamp, the number of samples in the packet, and the indication information and performing echo cancellation therewith.

Remote echo cancellation in a packet based network


A video chatting method and system are provided. The method and system describe collection of facial vector data, audio data, and interactive motion information of a user of a first client. The collected data may be transmitted to a second client. The second client, in turn, may generate a virtual avatar model of the user of the first client based on the received data. The second client may further display the virtual model, play sound in the audio data. The second client may also render the interactive motion information and facial data information of a user of the second client, and generate and display a virtual avatar model of the user of the second client. The provided method and system may decreases amount of data that may be transferred over the network. This may allow data transmission rate during video communication to be high enough for a smooth operation.

Along with the widespread use of mobile terminals, maturity of wireless network technologies has increased. Hence, communication by voice conversation and text message may no longer meet people's expectations and demands. Video and audio communication, especially for conducting business, has grown in popularity. While wireless networks may have a growing number of users, mobile networks has not seen that level of popularity and penetration in terms of number of users. Slow data-transfer speeds and relatively high costs may be some of the reasons obstructing the use of mobile networks and development of instant video communication on mobile networks. Further, performance capabilities of mobile terminals may also adversely affect user experience, for example low definition cameras on mobile terminals may affect user experience during video communication.
Instant communication software installed on a mobile terminal may, generally, enable video and/or audio communication. Usually, such software operates by recording audio and video by microphone and camera respectively, compressing the audio and video data synchronously for transmission via network, and playing video images at another client, receiving the communication. Such communication may also be achieved by instantly transforming video images via a virtual camera, displaying video images as virtual profile video data using face identification technology, transmitting the generated video data via the network, and playing the video images at the receiving client.
Typically, during video communication using mobile terminals, video data transmitted via a mobile network may cause heavy network traffic, i.e. high bandwidth usage. Limited by the speed, bandwidth and costs of existing mobile network, data transmission during video communication at mobile terminals may be slow and expensive.

TENCENT TECHNOLOGY (SHENZHEN) COMPANY LIMITED


Improvements in an exteriorly mounted cat litter station, called “Kitty Cat Can”, mounts on the exterior of a building to create a bump-out toilet for cats, which live indoors. It is installed against an opening through a wall so cats can go back and forth without leaving the house. A hinged roof slops with long eave extensions and covers the screened slots at the top of the outer container for water tightness. This seamless unit mounts, held by its own weight, onto an integrated horizontal ledger hook which has been installed on the exterior of a dwelling. Optional openings in the back provide flexibility upon installation. A secondary high-walled reusable container fits snuggly inside and is held in place by the removable passage sleeve. Liner and sleeve stay in place for routine litter raking, although if more aggressive cleaning is desired, the sleeve and liner lift out completely.

Field of the Invention
This invention relates to improvements in a cat litter box. More particularly, the present "Kitty Cat Can" Exterior Mounted Litter Box for In-Door Cats & Kittens & Other Small Animals allows an in-door pet to essentially exit through a wall and utilize a litter box that is mounted to the outside of the house.
Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Many pet owners have in-door pets that don't travel outside of the house where the animal can permanently leave or become harmed by other animals that live around the house. There are other pet owners that do not want a house to smell like animals. The smell is often generated by a litter box which also takes up valuable space in a home. Moving the litter box outside of a house often requires the animal to exit the safety and security of the house. An option to satisfy these issues is to secure an enclosed litter box to the outside of a house and then cut a hole from the inside of a house into the enclosed exterior litter box. A number of patents and or publications have been made to address these issues. Exemplary examples of patents and or publication that try to address this/these problem(s) are identified and discussed below.
U.S. Pat. No. 5,975,017 issued on Nov. 2, 1999 to Eddie M. Cameron discloses an Exterior Mounted Housing for Animal Litter Box. This patent has a housing that is mounted on the exterior side of a dwelling having a storage compartment for removably holding a litter box. A hollow open-ended tunnel interconnects the interiors of the dwelling and housing respectively. While this patent discloses an exterior mounted litter box, access to the litter box is available from the side of the litter box and further includes an upper sleeping area that is not accessible for cleaning.
U.S. Pat. No. 6,439,161 issued on Aug. 27, 2002 for Ronald E. Clemmons discloses an Exterior Litter box. This patent has a litter box enclosure mounted on or against an exterior wall of a structure includes a gated passage permitting a pet free access to and from a litter container. The litter box in this patent is on a pivoting base whereby rotating the litter box empties the litter into a collection bag located under the enclosure and also creates plastic landfill waste. This patent has minimal access for cleaning the interior of the enclosure.
U.S. Patent publication 2003/0168017 was published on Sep. 11, 2003 for Jack Aldon Perelli et al., discloses a Cat Outhouse and Method for Using Same. The cat outhouse attaches to the exterior of a house and comprises a box-like shelter, a litter pan, and at least one pass-through door so that the cat can enter the litter box from the inside of the house. While this cat outhouse allows for an exterior litter box, access to the litter box is with a side door, and further sits on the ground where water can flow into the outhouse.
What is needed is an outhouse for an indoor pet. The Ideal outhouse would be mountable to hang onto an exterior wall of a building were animals would be able to go in and out from where they live indoors. Animals would have the convenience of an outhouse to have the choice for privacy and a choice to keep their living space preferably clean and fresh. The outhouse should be seamless in appearance with a hinging roof that locks and slopes to shed water over protected ventilation. It should be roomy inside with high walls to discourage liquid from being trapped in unwanted places. It should have a high walled removable litter liner that may be used over and over to ease landfill waste. The outhouse in this document provides a solution.

“Kitty cat can” exterior mounted litter box for in-door cats and kittens and other small animals


Disclosed is a method for making a membrane for use as a vacuum bag, a natural rubber vacuum bag made using such methods, and methods for using such a natural rubber bag to form a composite article. One method can include providing a substantially non-porous working surface having a desired shape for forming a vacuum bag, spraying at least one layer of a natural rubber liquid over at least a portion of working surface, and solidifying the natural rubber liquid to form a membrane having a shape substantially corresponding to that of the working surface. The membrane formed being elastically deformable and substantially impermeable for functioning as a vacuum bag in Vacuum Assisted Resin Transfer Molding, debulking, compaction, or similar processes.

Composites are defined broadly as the combination of two or more dissimilar materials to produce a new material that has synergistic properties that were not present in the individual constituents alone. In practical terms, the word composite is generally associated with reinforced plastic material such as fiberglass structures. In the case of fiberglass, beneficial synergistic properties including corrosion resistance, low weight, high strength, and low cost are attainable in a highly variable array of product geometries.
Fabrication of a composite article such as a fiberglass boat hull requires the combination of a solidifiable resin system with a "preform" that could include glass fibers, veils, flow media and cores. There are many processes available for the purpose of impregnating a preform with liquid resin in order to make a composite. These processes may be broadly characterized into two categories, wet lay-up "open molding" and resin infusion "closed molding."
Open molding processes tend to produce a final component having a low fiber volume fraction (i.e., lower relative amount of fiber compared to the amount of resin). They are also labor intensive to manufacture because each layer of preform material must be individually coated with resin and carefully positioned by hand. Further, the inherent nature of open molding processes can allow air bubble entrapment to occur inside the composite, and the completed part can have a non-uniform thickness and fiber volume fraction.
In addition, open molding often leads to direct worker exposure to Volatile Organic Compounds (VOC) and Hazardous Airborne Pollutants (HAP). Both VOC and HAP are recognized by the EPA as potential health hazards for which alternative control technologies should be sought. As a result, although exceptions can be found, these deficiencies generally result in articles formed by open molding techniques being disfavored where other methods are available.
By comparison, closed molding—and more particularly resin transfer molding (RTM)—overcomes many of the limitations of wet lay-up processes. RTM involves a preform being constrained under pressure within a mold cavity whereupon resin is forced into the open spaces remaining. Resin infusion methods limit exposure to VOC and HAP and allow for better control over part dimensions and fiber volume fraction. RTM molds are typically made from matched steel mold platens which are supported in a hydraulic press due to the high injection pressures required to force resin through a highly compacted preform. The escalating cost of fabricating rigid molds for parts in excess of about 100 square feet tends to limit the size of parts considered for RTM.
Vacuum Assisted Resin Transfer Molding (VARTM) is a variation of RTM that achieves preform compaction by removing air located between a single sided rigid tool and a flexible vacuum bag that encapsulates a preform placed on the tool. Tooling costs are significantly reduced because there is only one tool surface and atmospheric pressure replaces the hydraulic press. VARTM provides a closed mold solution for complex and/or large parts that were previously not considered infusable. A desirable element of a VARTM mold is a vacuum bag that has sufficient elasticity to accommodate the strains associated with preform compaction as air is removed. It is further desirable for the vacuum bag to be sufficiently impermeable so that air does not leak through the bag and adversely affect the flow of resin or leave air pockets within the composite product. A vacuum bag should also provide a sufficiently snug fit around a preform to prevent the formation of creases and/or bridges which can become resin runners leading to inconsistent flow fronts.
The most common vacuum bag currently used for VARTM is a single-use Nylon film, and variations are available with more or less stretch, heat resistance, tear strength and thickness. Films are sold in flat sheet stock requiring fabricators to cut, paste and seam sections together as needed to build a suitable vacuum bag. While suppliers are now offering the convenience of thermally seamed near net shape film bags, Nylon films are not reusable and thus end up in the dump after each mold run. Furthermore, disposable bags of this kind rarely provide sufficient elasticity to eliminate bag bridging and or bulging which can lead to inconsistent infusions and dry spots in the molded composite article.
The composites industry is beginning to recognize that reusable vacuum bags are a desirable component of economically viable production closed molding programs, with bag longevity being a key factor. Reusable bags must withstand significantly more wear and abuse than disposable bags. A variety of Synthetic rubbers have been used to make reusable vacuum bags, including calendared rubber sheets of EPDM, Silicone, butyl, fluoroelastomers, nitriles and polyisoprenes and room temperature vulcanizing (RTV) silicones, all of which originate from a petroleum feed stock.
For reasons of transparency and the ability to make near net shape constructions, RTV silicone systems have become the material of choice for making reusable vacuum bags. Vacuum bags made from calendared silicone sheets require seam treatments of either RTV silicone or a beta staged silicone material that must be subsequently cured with heat and moisture. Reusable bags are also made from semi-cured silicone sheet stock that is cut into desired shapes, draped in place on the mold surface upon which the seams are troweled over to create low profile joints. Another method involves spreading an uncured thixotropic RTV silicone liquid uniformly over a mold surface prior to curing it. In all of these instances, the procedure for building a reusable silicone vacuum bag is tedious and requires skilled labor.
Silicones have poor puncture and tear resistance, however, and therefore must be reinforced or thickened for durability, which makes them susceptible to the bridging effect in addition to being unnecessarily heavy and cumbersome to manipulate. For very large parts such as boat hulls, bridge decks, and wind blades, the weight of a given bag can become a significant issue. Large bags often need to be lifted mechanically and therefore require lift points. Bag strength becomes a critical factor because thicker bags weigh more and droopy bags can get caught on foreign objects and become damaged.
Attempts have been made to spray silicone rubbers with mixed results. Typical RTV silicones have high viscosity and are thixotropic which makes them difficult to spray because the material does not flow easily. It is thus difficult to achieve uniform bag thicknesses over large areas because the product must be toweled out after being applied to the surface. It is possible to reduce the viscosity of RTV silicones with the addition of solvents, but this remedy has the potential to become a source of VOC and HAP. Spray equipment that atomizes the silicone also runs the risk of contaminating the surfaces of neighboring articles exposed to the overspray and can become a major problem for adhesive bonding and/or painting operations carried out in the vicinity.
In light of the factors that should be considered when fabricating a composite article, there still exists a need for a durable, reusable vacuum bag for use in closed molding and vacuum bagging applications that limits the production of VOC and HAP and minimizes the overall environmental impact.

Method of making a natural rubber vacuum bag by spray processes, natural rubber vacuum bag made using spray process, and method for using natural rubber bag made using spray process


A spindle structure in which a noise occurrence due to a tap hole and a screw is effectively prevented. A nut for adjusting a preload of a bearing is threadedly engaged with an outer circumference of a spindle. On an edge of the nut, a plurality of tap holes for balance adjustment are provided at even intervals on a circumference centered around the axis of the spindle and to be parallel to the axial direction of the spindle. These tap holes are countersunk, and a plate screw is threadedly engaged so that an edge of each plate screw is flush with a surface of the nut. In addition, the plate screw is used as a balance weight by changing the length thereof.

1. Field of the Invention
The present invention relates to a spindle structure of a machine tool etc., and more specifically, to a technology to prevent noise which occurs when the spindle rotates at high speed.
2. Description of the Related Art
Generally, a spindle rotating at high speed has a tap hole for balance adjustment on an end surface or has other parts such as a dog for detecting a position mounted by a screw. Thus, when the spindle is rotated, there is a problem in which an external wind noise occurs due to the tap hole and a protruding head of the screw. To solve the problem, as disclosed in Japanese publication of unexamined patent application 2000-218465, a cover for covering the rotating portion, or a lid for covering the tap hole has been used.
However, the noise reduction effect is small even when the rotating portion is covered by a cover. Further, the lid protrudes from an edge of the spindle even when the tap hole is covered with the lid, resulting that external wind noises occur due to the protruded lid. Although the entire spindle is covered, the external wind noise reduction is small if the noise generated by the cover is considered. In other words, it is very difficult to reduce the noise completely.
In view of the above, the object of the present invention is to provide a spindle structure to effectively prevent a noise occurrence by a tap hole and a screw.


A nonvolatile memory device is provided. The device comprises a memory transistor. A first capacitor is coupled to the memory transistor. A second capacitor is coupled to the memory transistor. The second capacitor comprises a first electrode and a second electrode. The first capacitor and the second capacitor are connected to separate input terminals.

A nonvolatile memory device retains stored data even if power is turned off. Nonvolatile memory is currently available in several forms, including electrically erasable programmable read only memory (EEPROM) and flash EEPROM. Current flash memory architecture utilizes a memory transistor having a gate electrode over a semiconductor substrate and a dielectric layer between the gate electrode and the semiconductor substrate. A drain region in the substrate may be adjacent to the dielectric layer of the memory transistor and a source region in the substrate may be adjacent to an opposite side of the dielectric layer from the drain region. The gate electrode may be a floating gate. An n-well capacitor coupled to the gate electrode may be used to bias the floating gate.
Programming the memory device may result in storage of electrons in the floating gate and erasing the memory device may expel the stored electrons in the floating gate. During programming, a high voltage above 9V may be applied to the n-well capacitor and to the drain of the memory transistor. A lower voltage may be applied to the source of the memory transistor and the semiconductor substrate may be grounded. A strong vertically oriented electric field in a channel region between the source and the drain may be created resulting in injection of hot electrons to an edge portion of the floating gate from the channel region. During erasing, a high voltage above 9V may be applied to the drain. The n-well capacitor, the source and the substrate may be grounded. Electron hole pairs may be generated in the drain region by band to band tunneling (BTB). The generated holes may be accelerated by a lateral electric field toward a channel region between the source and the drain and some of them may obtain high energy. The hot holes may be injected into the floating gate through the dielectric layer and recombine with the electrons stored in the floating gate.
As high voltages are required for the program and erase operations, low voltage devices such as 3V or 5V devices may face challenges as high voltages are usually generated by a charge pump circuit which is composed of low voltage devices such as 3V or 5V devices. The erase mechanism is inefficient as the n-well capacitor is grounded. The n-well capacitor may be adjacent to a p-substrate. It is not possible to apply a negative voltage to the n-well capacitor to improve the erase efficiency as it may induce unwanted forward bias current between the n-well capacitor and the adjacent p-substrate. Thus, there is an urgent need for an improved flash memory device structure to overcome the challenges mentioned above.

One transistor two capacitors nonvolatile memory cell


A chronically implanted medical device, connected to a medical electrical lead that includes a sensor, is used to detect cardiac afterload. Electrical stimulation is delivered proximate to aortic arch tissue of a patient in order to reduce a patient's cardiac afterload. Electrical stimulation is terminated after a termination condition is met.

Patients with diastolic heart failure, hypertension and hypertrophy can exhibit elevated cardiac afterload. Cardiac afterload, the impedance to ventricular emptying by aortic pressure, can substantially determine regulation of cardiac output. Cardiac output is the volume of blood flow from the heart which is the heart rate (i.e. the rate of contraction) multiplied by the stroke volume which is the amount of blood pumped out from the heart with each contraction. A high cardiac afterload significantly reduces cardiac output whereas a reduced cardiac afterload increases cardiac output.
Current therapies rely on drugs to reduce cardiac afterload. At least two disadvantages are associated with drugs to reduce cardiac afterload. First, while drugs have had limited success, some patients are nonresponders. Second, chronic use of drugs to reduce cardiac afterload have some undesirable side affects. Therefore, it is desirable to develop therapies that overcome the disadvantages associated with drugs.

Aortic pacing to control cardiac afterload


An improved image data processing architecture utilizes a negotiation protocol with an information push technique to provide a more efficient and effective image data rendering pipeline. The improved image data processing architecture allows the optimization of data transfer through the use of image transfer parameters and flags. In another aspect of the invention, a selection mechanism is provided to allow a client application to easily select an image frame as the current frame in a multi-dimensional image. Image sinks within the invention may further support non-blocking behavior.

Image processing is critical to many computer-related endeavors, such as the display of graphics received over a network, or rendering of an image from a file of image data. Quite often image data is stored or received in a form that requires transformation prior to rendering. For example, image data may have to be scaled, decompressed and so on before it is in the format appropriate for the rendering entity. The process by which image data is received, transformed, and rendered is referred to as the "image pipeline" or "image rendering pipeline."
In an object-oriented environment, the pipeline is made up of a series of source and sink objects that accomplish the desired transformations. For example, compressed image data may be received from a network connection by a decoder object, which acts as an image data source for the subsequent object in the image-rendering pipeline. The subsequent object, or "sink", could perform for example an encoding or scale transformation function, and might in turn act as an image data source for another object further along in the pipeline.
Traditionally, the image rendering pipeline components have been constructed to utilize a "pull" architecture. In general pull technologies essentially entail a data consumer specifically requesting information from a particular data provider. Downloading a Web page with a Web browser is a high level example of the use of pull technology. In the context of the image rendering pipeline, the use of pull technology generally means that a transaction between a data source and a data sink is driven by the data sink rather than the data source. Thus in the pipeline example above, the sink would specifically request the image data from the source, which is a decoder in this example. If the source does not currently have the data being requested, due for example to a delay on the network connection, then a potentially protracted waiting condition could occur. Another drawback to the use of pull technology is excess memory usage; at any given point in time, the sink is not necessarily aware of the image data currently possessed by the source, and consequently cannot know exactly when to ask for a particular item of data. Consequently, the source will generally store its received data at least until it receives a request for the data from the sink.
Pull technology may be contrasted with "push" technology. The term "push" technology refers to a data distribution technology in which selected data is delivered from a data source to a data sink at a time and in a manner determined by the source rather than the sink. Again using the Internet as a high level example, PointCast is a service which uses push technology. PointCast was an early provider of a service capable of delivering a selection of news and stock quotes to a user's computer at certain intervals without a contemporaneous request for the data.
While there exist image rendering pipeline technologies that utilize push architecture, these technologies do not utilize the full potential of push technology because they lack a mechanism for optimizing the particular image data transfer parameters as a function of the needs and capabilities of both the source and sink.

This patent is subject to a terminal disclaimer.


A friction clutch system is disclosed to couple a drive shaft and a driven shaft together by hydraulically urging clutch surfaces together. A pump for pressurizing the hydraulic system is mechanically coupled between the drive and driven shafts to rotate at speeds increasing with the difference in their respective speeds.

Friction clutches are well known. Such clutches are typically spring-biased to an engaged position. This is a disadvantage in that the friction clutches are spring-biased under initial constant bias pressure which cannot be adjusted to varying conditions.
Such conventional clutches have the disadvantage that on movement from a disengaged position to an engaged position, they rely on the skill of the operator to smoothly re-engage the clutch.
Clutch disengagement devices are known whereby as a precondition of moving a shift lever, the disengagement device automatically disengages the friction clutch. Such known devices, however suffer the disadvantage that conditions for re-engagement are preset and do not vary to accommodate different drive and driven shaft conditions. Jerky shifting, engine stalling and excessive clutch wear can result producing possible hazardous situations when used in passenger vehicles.


A downhole tool comprising a body and a sealing element, wherein the sealing element is composed of a composite material comprising a rubber and a degradable acrylate-based polymer, and wherein at least a portion of the degradable acrylate-based polymer degrades when exposed to an aqueous fluid in a wellbore environment.

The present disclosure generally relates to downhole tools comprising a body and a sealing element composed of a composite material comprising a rubber and a degradable acrylate-based polymer, wherein at least a portion of the degradable acrylate-based polymer degrades upon exposure to an aqueous fluid in a wellbore environment.
A variety of downhole tools are within a wellbore in connection with producing or reworking a hydrocarbon bearing subterranean formation. The downhole tool may comprise a wellbore zonal isolation device capable of fluidly sealing two sections of the wellbore from one another and maintaining differential pressure (i.e., to isolate one pressure zone from another). The wellbore zonal isolation device may be used in direct contact with the formation face of the wellbore, with casing string, with a screen or wire mesh, and the like.
After the production or reworking operation is complete, the seal formed by the downhole tool must be broken and the tool itself removed from the wellbore. The downhole tool must be removed to allow for production or further operations to proceed without being hindered by the presence of the downhole tool. Removal of the downhole tool(s) is traditionally accomplished by complex retrieval operations involving milling or drilling the downhole tool for mechanical retrieval. In order to facilitate such operations, downhole tools have traditionally been composed of drillable metal materials, such as cast iron, brass, or aluminum. These operations can be costly and time consuming, as they involve introducing a tool string (e.g., a mechanical connection to the surface) into the wellbore, milling or drilling out the downhole tool (e.g., at least breaking the seal), and mechanically retrieving the downhole tool or pieces thereof from the wellbore to bring to the surface.
To reduce the cost and time required to mill or drill a downhole tool from a wellbore for its removal, dissolvable or degradable downhole tools have been developed. Traditionally, however, such dissolvable downhole tools have been designed only such that the dissolvable portion includes the tool body itself and not any sealing element of the downhole tool. This is particularly evident because the dissolvable materials that have been proposed for use in forming a downhole tool body are often highly brittle and are physically or chemically incapable of exhibiting expansive or elastic properties necessary for a sealing element. Instead, the known dissolvable downhole tools may dissolve such that it no longer provides the structural integrity necessary for achieving an effective seal with the non-dissolvable sealing element.

Downhole tools comprising composite sealing elements


A purchaser apparatus stores “anonymous order information including an order ID and purchaser identity verifying information” and “purchaser identity proving secret information”. A shop apparatus stores “anonymous order information including an order ID and purchaser identity verifying information”. If necessary, a purchaser sends a request including an order ID and zero knowledge proving information that a purchaser knows the purchaser identity proving secret information, from a purchaser apparatus to a shop apparatus. A shop apparatus verifies the zero knowledge proving information, based on purchaser identity verifying information retrieved from an order ID included in the request. Therefore, the unlinkability for past use is eliminated if necessary, and inconvenience caused by the unlinkability is eliminated.

1. Field of the Invention
The present invention relates to a shop apparatus for an anonymous order, a purchaser apparatus, a purchaser identity proving apparatus, and a purchaser identity verifying apparatus using a group signature scheme.
2. Description of the Related Art
In the field of providing online sales service, techniques using a group signature scheme (for example, D. Chaum, E. Van Heyst, "Group Signatures", EUROCRYPT '91, LNCS 547, Springer-Verlag, pp. 257-265, 1991, G Ateniese, J. Camenisch, M. Joye and G. Tsudik, "A Practical and Provably Secure Coalition-Resistant Group Signature Scheme", CRYPT 2000, LNCS 1880, Springer-Verlag, pp. 255-270, 2000. Atsuko Miyaji, Hiroaki Kikuchi, "Information Security", Ohm, ISBN4-274-13284, pp. 112-114) has been proposed from the viewpoint of realizing protection of personal information and privacy (for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-054905, 2004-320562 and 2006-119771).
In the proposed techniques, protection of personal information and privacy of users is realized by anonymity and unlinkability. Anonymity mentioned here refers to the property that prevents disclosure of personal identity. Unlinkability refers to the property of the inability to judge whether two different authentication requests are made by the same user.
The proposed techniques have traceability, and realize separate payments for each service in a usual operation and specification of an unauthorized user upon occurrence of an illegal access, at the same time. Traceability is a function in which only a predetermined personal information managing organization other than a service provider can identify a user.
However, although unlinkability is an important property from the viewpoint of protection of personal information and privacy, it may cause inconvenience to a service provider. For example, when a user wants to inquire about or return purchased goods and services, as unlinkability is given to the purchased goods and services, such user's requests may not be directly handled only between the user and service provider. Further, when the same user repeatedly uses the same service provider, as unlinkability is given to the purchased goods and services, the number of times the user uses the service provider is unknown. This means that benefits such as offering point services or the gathering of market information regarding usage cannot be carried out.
In the service providing systems used prior to the above-mentioned proposed techniques, as a person is always identified, although actions to inquire/request return of merchandise and provision of point service are easy to provide, protection of personal information and privacy is difficult to realize.
In the above proposed techniques, as unlinkability is always maintained, a high level of protection of personal information and privacy can be realized. On the other hand, having unlinkability may make it difficult to inquire based on past use or request to return merchandise, or provide point service based on past use.


In a brake-pressure control device for a road vehicle, having an antilock braking system whose braking device comprises a vacuum brake power assist unit which has a vacuum chamber connected to the intake stub of the vehicle engine and a working chamber which can be subjected to a higher pressure via a control element operable by the brake pedal, a position sensor is provided which detects the position of the brake pedal and generates output signals. An electronic control unit processes these signals and generates drive signals for a brake-pressure control device making it possible to couple into the wheel brakes a higher brake pressure than would otherwise correspond to the instantaneous pedal position. Such driving of the brake-pressure control device is triggered when the speed .PHI. at which the brake pedal is operated overshoots a prescribed threshold value .PHI..sub.s. The brake power assist unit is provided with a solenoid valve arrangement which can be moved from a basic position in which pressure compensation can be performed between the vacuum chamber and the working chamber of the brake power assist unit, whereas the working chamber thereof can be connected only via the control element to the outside atmosphere, into a functional position in which the working chamber is subjected to the ambient pressure but is blocked off from the vacuum chamber.

The present invention relates to a brake-pressure control device for a road vehicle, having a hydraulic braking system, preferably a dual circuit braking system, and, more particularly to a brake pressure control device having a hydraulic multiple circuit braking system configured such that wheel braking is effected by operation of a brake pedal, a braking device comprising a master cylinder having output pressure chambers individually assigned to brakes and a pneumatic brake power assist unit having a vacuum chamber connected to an intake stub of a vehicle engine and a working chamber configured to be subjected, via a control element operable by the brake pedal, to a pressure higher than a pressure prevailing at the intake stub, sensor to detect a position of one of the brake pedal and an element motively coupled thereto and to generate electrical output signals characteristic of at least one of instantaneous position of the brake pedal and variations therein, and/or a force transmitter which generates output signals characteristic of a force with which a vehicle driver operates the brake pedal when braking, and an electronic control unit operatively associated with the sensor and/or the force transmitter such that, by processing signals from one of the sensor and the force transmitter, output signals are generated by the electronic control unit as drive signals for a brake-pressure control device so that, during a driving operation, a higher brake pressure than the brake pressure otherwise to be expected in accordance with the instantaneous pedal force can be coupled into individual wheel brakes, furthermore, driving of the brake-pressure control device for the purpose of increased brake-pressure deployment being triggered when at least one of a speed at which the brake pedal is operated for the purpose of a brake pressure build-up and a rate of variation of the force at which the vehicle driver operates the brake pedal is higher than a prescribed threshold value.
Provided in the foregoing type of braking system as a braking device is a master cylinder which is operable via a vacuum brake power assist unit of conventional configuration and which has output pressure chambers individually assigned in each case to the brake circuits. The pneumatic brake power assist unit has a vacuum chamber connected to the intake stub of the vehicle engine and a working chamber which is movably bounded with respect to said vacuum chamber by the working piston of the brake power assist unit and which can be subjected via a control element which performs the function of a 3/3 way control valve and is operable by the brake pedal to a pressure higher than the pressure prevailing at the output stub of the vehicle engine. As a result, the master cylinder can be operated by a force which is boosted with respect to the pure pedal force and which supports the brake pressure build-up in the wheel brakes. A displacement or position sensor is provided as an element of the brake-pressure control device to monitor the pedal position and generate electrical output signals characteristic of the instantaneous position of the brake pedal and thus also of variations therein. By the processing of these output signals there are obtained, via an electronic control unit, drive signals for a brake-pressure control device by way of which--in the event of drive--it is possible to couple into the wheel brakes a higher brake pressure than the brake pressure otherwise to be expected in accordance with the instantaneous pedal position, driving of the brake-pressure control device for the purpose of increased brake pressure deployment being triggered when the speed .PHI. at which the brake pedal is operated is higher than a prescribed threshold value .PHI..sub.s. Instead of, or in combination with, monitoring the pedal position and its rate of variation, it is also possible to monitor the force K.sub.p with which the driver operates the brake pedal and its rate K.sub.p of variation and to trigger the increased brake force deployment when the rate K.sub.p of variation overshoots a threshold value K.sub.s. It is assumed that the vehicle is equipped with an antilock system which during braking regulates the dynamically stable deceleration behavior of the vehicle.
DE 40 28 290 C1 discloses such a brake-pressure control device required for automatic control of a method for shortening the braking distance in critical driving situations. If during pedal operation the speed threshold value .PHI..sub.s exceeded, that known device builds up as high as possible a brake pressure in the shortest possible time as far as a brake pressure which produces full braking. The brake pressure is limited, however, by the dominant effect of the antilock system in accordance with the respectively prevailing road conditions.
The realization of this brake pressure control concept is possible, for example, by way of a brake-pressure control device which, by analogy with a traction control system (TCS) which operates in accordance with the principle of once again decelerating by automatic actuation of its wheel brake a driven vehicle wheel tending to spin, also performs this function for the wheel brakes of the non-driven vehicle wheels, when the threshold value .PHI..sub.s of the speed is exceeded at which the driver operates the brake pedal.
Such a realization of a brake-pressure control device acting on all the wheel brakes by analogy with a TCS, which would require blocking off the brake circuits from the braking device, has the disadvantage, however, that with the onset of the automatically controlled braking operation there is a loss of any reaction of the brake pressure coupled into the wheel brakes on the brake pedal. The brake pedal would then become "hard", that is no longer capable of further depression. Thus a pedal reaction occurs which, in the case of a fair number of drivers, will give the feeling that the braking system is not in order and will then lead to an inadequate reaction of such a driver; for example, retraction of the brake pedal and subsequent renewed operation thereof because the driver suspects, for example, that "additional" brake fluid must be "pumped" or fed into the master brake cylinder, and is thus led to take measures, momentary discontinuance of braking--which would certainly be inappropriate in a traffic situation requiring full braking.
In order to avoid this disadvantage, a brake-pressure control device is described in the pending German application P 41 02 497.4-21 which is suitable for carrying out the known method and provides buffer accumulators assigned to the brake circuits. The accumulators can be connected, in a valve-controlled manner, to the pressure outputs of the braking device by an output signal of the electronic control unit which activates the brake-pressure control device. The accumulators are blocked off from the brake circuits, however, and can be recharged against a smaller restoring force than a reaction force otherwise resulting from reaction of the brake pressure on the braking device and directed against the operating force, so that during braking, bracking fluid can be displaced into these buffer accumulators from the braking device. As a result, pedal travel becomes possible and, even after the onset of the automatic brake pressure control, a pedal feeling is retained which is essentially the same as in normally occurring braking, so that the driver cannot be irritated or distracted by the automatic brake pressure control.
In the brake-pressure control device in accordance with the aforementioned Application P 41 02 497.4-21, however, the technical outlay and space required in connection with the buffer accumulators and with the solenoid valves required therefor to be coupled to and blocked off from the braking device as needed are substantial and, to this extent, disadvantageous.
A vehicle is disclosed in DE-38 18 708 A1 having a hydraulic dual circuit braking system which is operable via a vacuum brake power assist unit of special design comprising a vacuum chamber (modulation chamber), a working chamber and a simulation chamber which in the brake release position is held connected in a communicating manner to the working chamber to obtain an antilock regulating function, i.e. reducing the brake pressure, by connecting the vacuum chamber which is normally at a lower pressure than the atmospheric pressure, in a valve-controlled manner to the ambient atmosphere. Consequently, a tappet acting on the push rod piston of the master cylinder of the braking system experiences a return movement as a result of which the pressure prevailing in the master cylinder is reduced. This return movement does not lead to a reaction on the brake pedal, since the input of the pedal operating force is performed via a brake valve whose housing displacement inside a simulator housing permanently remains, due to the effect of the pressures acting in the working chamber and in the simulation chamber, in a defined basic position, against the restoring force of simulation springs, which alone determine the "pedal feeling" which is communicated to the driver as feedback on the brake pressure corresponding to his wishes.
The known braking system described in DE-38 18 708 A1 can also be utilized to realize a traction control system by arranging the simulation chamber, which is normally connected to a vacuum source, to be blocked off from the vacuum source in a valve-controlled manner independently of pedal operation of the braking system. The working chamber is subjected to the ambient pressure, as a result of which the master cylinder is operable for the purpose of brake pressure build-up. Brake-pressure reduction phases which become necessary in the course of the traction control can be controlled in a manner analogous to the antilock control operation. However, if the known braking system operation is controlled by the brake pedal, the brake pressure build-up is always performed in a manner proportional to the operating force, so that raising the brake pressure above an amount input by the driver by his or her operating force is not possible by way of this braking system. The known braking system is therefore not suitable for realizing an automatically controlled braking operation in which, in an introductory phase of braking, a brake pressure deployment disproportionately increased with respect to the operating force is possible.
It is therefore, an object of the present invention to provide a brake-pressure control device which is suitable for carrying out the known method; facilitates, in conjunction with a nevertheless simple and cost-effective design, control in accordance with the method of an automatic braking operation in connection with a high vehicle deceleration; and thereby produces a pedal reaction largely corresponding to the accustomed pedal travel/brake force correlation.
The foregoing object has been achieved according to the present invention by providing the vacuum brake power assist unit includes a solenoid valve arrangement driven by one of the electrical output signals of the electronic control unit and movable from a basic position, in which a control duct of the control element, via which pressure compensation can be performed between the vacuum chamber and the working chamber of the vacuum brake power assist unit, is communicatingly connected to the vacuum chamber, whereas the working chamber of the vacuum brake power assist unit is blocked off from the outside atmosphere, into an excited functional position in which the control duct of the brake power assist unit is subjected to the ambient pressure via a flow path of the solenoid valve arrangement that is released in the functional position, whereas the control duct is blocked off from the vacuum chamber, the basic position of the solenoid valve arrangement being assigned to a non-operated state of the braking system and to the target braking operation thereof and the valve arrangement passing into its excited position when, during operation of the brake pedal, at least one of the threshold value of the rate of operation and the threshold value of the rate of variation of the operating force is overshot, and a valve is operatively associated to respond to the pressure in the control duct, is subjected to an opening direction to a relatively higher pressure in the control duct than in the working chamber and is otherwise blocked, and via which the control duct can be connected directly to the working chamber of the vacuum brake power assist unit.
A solenoid valve arrangement is provided as an auxiliary device on the vacuum brake power assist unit. When driven by the output signal of the electronic control unit which is characteristic of the rapid operation of the brake pedal, the solenoid valve arrangement can be switched over from a basic position, which is assigned to the non-operated state of the braking system and to the soft target braking operation thereof and in which a control duct of the control element of the brake power assist unit, via which pressure compensation can be performed between the vacuum chamber of the latter and its working chamber, is connected in a communicating manner to the vacuum chamber. The working chamber of the brake power assist unit is blocked off from the outside atmosphere, into an excited functional position which is assigned to the automatically controlled full braking and in which the control duct of the brake power assist unit is subjected to the ambient pressure via a flow duct of the solenoid valve arrangement that is released in this functional position, whereas the control duct is blocked off from the vacuum chamber of the brake power assist unit. By way of this solenoid valve arrangement, the accustomed pedal feedback is obtained due to the fact that the vacuum brake power assist unit is utilized during automatically controlled full braking in order to operate the master cylinder, with a drastically increased boost factor, at least to the extent that the brake pedal can at least follow up the brake power assist unit piston independently of which force has to be expended for this purpose by the driver. Thus, a pedal travel/vehicle deceleration correlation of an accustomed type is retained and the driver cannot be irritated or confused.
A valve which responds to the pressure in the control duct is pressurized in the opening direction by pressure in the control duct which is relatively higher than in the working chamber, is otherwise blocked and can directly connect the control duct to the working chamber. It is possible for this valve to be constructed as a check valve, and in a preferred configuration as a simple flutter valve, which sealingly covers the discharge opening of a transverse duct, which originates from the control duct and discharges into the working chamber, as long as the pressure in the working chamber is higher than in the control duct and, in a special configuration, is formed by an elastomeric lip which, subjected to moderate biasing covers the discharge opening of the transverse duct on the drive side. By way of this valve, it is possible for the control duct of the control element of the brake power assist unit to be connected directly to the working chamber thereof even if the control element, which in accordance with its function is a 3/3 way control valve having two alternative flow positions and one blocked position, is in the blocked position, which is adopted during normal braking when the driver no longer depresses the brake pedal upon the achievement of a desired vehicle deceleration. A desired rapid response of braking with a high boost factor at the onset is achieved by virtue of this valve, especially at the start of automatically controlled braking.
The brake-pressure control device according to the present invention can be realized by two 2/2 way solenoid valves, one of which provides in its excited position a direct connection between the working chamber and the outside atmosphere and is otherwise blocked, and the other of which provides in its basic position the connection between the control duct and the vacuum chamber and interrupts the connection in its excited position. It is possible for the first of these two valves to be arranged "outside" the brake power assist unit, and for the second to be integrated into the control element housing, which can be moved together with the working piston of the brake power assist unit.
From the foregoing, it should now be apparent that the technical outlay to be made for the brake-pressure control device according to the present invention corresponds at most to that which is necessary in the case of the brake-pressure control device according to the aforementioned German Patent Application P 41 02 497.4-21 merely for the connection control of the buffer accumulators further provided there, which control device is realized by 3/3 way solenoid valves.
Although flexible electrical supply lines and electrically insulating housing bushings are necessary for a solenoid valve integrated into the movable control element housing, the additional outlay in this regard is insubstantial compared with realizing the brake-pressure control device as provided in accordance with the German Patent Application P 41 02 497.4-21.
The only problem that could arise is the spatial arrangement of a valve, integrated into the control element, "inside" the brake power assist unit, which to this extent would require a design modification. However, outlay in this regard can be largely avoided, at least reduced, by leading the control duct to the outside via a flexible line and a bushing of the housing and arranging outside the vacuum chamber of the brake power assist unit a solenoid valve which in its basic position connects the bushing to a second bushing leading back into the vacuum chamber, and in its excited position adopted during driving by way of an output signal of the control device blocks off the first bushing from the second and in return connects the latter to the space outside the brake power assist unit, which is at atmospheric pressure. In such a configuration of the solenoid valve arrangement as a 3/2 way valve and arrangement of the latter "outside" the vacuum chamber of the brake power assist unit, only one valve is required, whose control current supply can also be performed via fixed electrical lines. When compared with a conventional vacuum brake power assist unit, the supplement, required to match the vacuum brake power assist unit to the brake-pressure control device according to the invention, of a flexible aerial line leading from the control duct to a first bushing of the vacuum housing, and of a second bushing, between which the brake-pressure control valve arranged outside the vacuum housing is inserted, entails only a small extra outlay and can therefore be realized cost-effectively.
It is especially advantageous when the brake-pressure control valve is constructed as a 3/3 way valve which by means of control signals of defined different control current strengths can be moved into its functional position II, which connects the control current duct to the outside atmosphere, and into a functional position I which blocks the control duct off from both bushings. It is possible to utilize the blocked position especially advantageously to control brake-pressure reduction phases in the course of which the brake-pressure control valve is switched over repeatedly between its basic position and the blocked position.
If, as provided in a preferred embodiment of the brake-pressure control device, the working chamber of the brake power assist unit can be subjected to a pressure higher than the atmospheric ambient pressure, the higher pressure being between approximately 1.5 and 2.5 (and preferably approximately 2 bars), it is possible to achieve increased braking forces during automatically controlled braking. An increase in the control point of the brake power assist unit is therefore achieved even during normal braking, when in this case the pump is activated. That is, it is possible to achieve relatively high braking forces via operating forces that are still relatively low.
In a simple embodiment that is advantageous in terms of circuitry, the pressure outlet of the compressed-air pump provided for the provision of the higher pressure is connected to the input, connected to the working chamber of the brake power assist unit during full braking, of the brake-pressure control valve via a first check valve which in the opening direction is subjected to relatively higher pressure at the pressure outlet of the pump than in the working chamber and is otherwise blocked. A second check valve is connected to the pressure inlet of the brake-pressure control valve and, in the event of relatively higher pressure at the pressure inlet of the brake-pressure control valve, is blocked and is otherwise open, so that the atmospheric pressure can be coupled into the working chamber of the brake power assist unit via the second check valve should the pump have failed.

Road vehicle brake-pressure control device


A clothes dryer and method for forming and supplying a treating chemistry solution to a laundry load located in the treating chamber of the clothes dryer.

Dispensing clothes dryers may have a configuration based on a rotating drum that defines a treating chamber in which laundry items are placed for treating according to a cycle of operation and a dispensing system for dispensing a treating chemistry as part of the cycle of operation. A controller may be operably connected with the dispensing system and various components of the dryer to execute the cycle of operation. The cycle of operation may be selected manually by the user or automatically based on one or more conditions determined by the controller. Even when the proper amount of treating chemistry is dispensed, the dispensed treating chemistry may result in the build-up of residue on the interior surfaces defining the treating chamber which may transfer to the laundry when it is not desired to do so or provide a spot concentration of treating chemistry.

Clothes dryer and method for adjusting a dilution of a treating solution based on a detected clothes load size


An integrated circuit having multiple power/ground connections to a single external terminal and method for manufacturing an integrated circuit provides an integrated circuit having a reduced number of external power/ground terminals. The multiple connections may be made by conductive circuit paths on one side of the substrate and a terminal pad on the same side of the substrate, with the conductive circuit paths leading from die terminals terminating at the terminal pad, or a via may be formed either directly above the terminal pad or contacting its circumference to provide a connection through from the opposite side of the substrate. Multiple vias may be formed above the terminal pad and within its circumference to provide connection of multiple die terminals to the terminal pad.

The present invention relates generally to semiconductor packaging, and more specifically, to a substrate having multiple connections to external terminals for providing electrical inter-connection between multiple power connections of one or more integrated circuit dies to a single external terminal.
Semiconductors and other electronic and opto-electronic assemblies are fabricated in groups on a wafer. Known as xe2x80x9cdiesxe2x80x9d, the individual devices are cut from the wafer and are then bonded to a carrier. The dies must be mechanically mounted and electrically connected to a circuit. For this purpose, many types of packaging have been developed, including xe2x80x9cflip-chipxe2x80x9d, ball grid array and land grid array among other mounting configurations.
High-density interconnect schemes such as high-density ball grid arrays (BGAs) or land grid arrays (LGAs) typically have multiple power and ground balls or lands in the array in order to provide a low impedance connection from the die(s) to the external power supply connections. Multiple terminals are also used to provide improved heat transfer from the semiconductor die(s) to the mounting carrier (e.g., printed circuit board or socket). In one terminal arrangement of these packages, the entire center section of the array is dedicated to power and ground connections.
The thermal and electrical impedances of the terminal (e.g., solder ball or land) do not necessitate the multi-terminal connection arrangement. Rather, it is the impedance of the wire-bonding structure (if used) and the impedance of the circuit traces on the substrate that necessitate the use of multiple terminals.
Therefore, it would be desirable to provide a method and integrated circuit package having a reduced number of power and ground terminals, while maintaining a low electrical impedance and a low thermal impedance connection from the integrated circuit die(s) to ground and power supply terminals. It would similarly be desirable to provide a method and integrated circuit package providing a higher-density interconnect by reducing the number of required power and ground connections.
A substrate having multiple power supply and/or ground connections between one or more die terminals to a single external pad provides a lower pin count or higher-density interconnect integrated circuit package. The integrated circuit includes at least one integrated circuit die, a substrate for mounting and electrically interconnecting the integrated circuit die(s) and a cover for covering the integrated circuit die(s).
The substrate includes multiple terminal pads for connection to external terminals of the integrated circuit and multiple bond pads for connection to terminals of integrated circuit die(s) where at least two power and/or ground connections from among bond pads are connected to a single terminal pad.

Integrated circuit having multiple power/ground connections to a single external terminal