A process for forming a spaced dyed yarn, where a yarn is conveyed to a dye application station where a coordinated stream of dye is projected in a normal stream path adjacent to a first side of the yarn. The dye is applied to the yarn when a gas nozzle projects a stream of gas such that it impinges the stream of dye and diverts the stream of dye across said yarn to an alternative deflected path adjacent to the opposite side of said yarn, causing the dye to sweep over the yarn and impact and color the yarn. Upon deactivation of said gas nozzle, the stream of dye passes back across said yarn to the first side of the yarn, impacting and coloring the yarn for a second time.

It is well known to utilize colored yarns within textile materials to impart desired aesthetic characteristics to the textile material. Color is generally imparted to yarns by use of bulk dyeing practices in which a single color is applied to bundles of yarn immersed within a dye bath. Typical dyes as are known to those of skill in the art include disperse dyes, acid dyes and basic dyes. As will be appreciated, upon completion of such a bulk dyeing operation, the dyed yarn is typically of a substantially uniform solid color. Thus, in order to provide a multi-colored appearance to a textile material formed from such bulk dyed yarns, it may be necessary to utilize a number of different colored yarns. However, the utilization of such bulk dyed yarns nonetheless tends to establish visually distinguishable patterns within the resulting textile material which maybe undesirable to some users.
It is also known to utilize so-called "space-dyed" yarns within pile-forming textile materials such as carpeting to provide a random or pseudo-random pattern within the material. One such carpeting material is illustrated and described in U.S. Pat. No. 5,413,832 to Willey the contents of which are incorporated by reference herein.
Several methods are known for space dyeing of yarns so as to impart segments of various colors along the length of such yarns. One such known method is the so-called "knit-deknit" method in which yarns are knit into a construction across which bands of color are introduced. The knit construction is thereafter unraveled so as to yield the lengths of yarn with substantially random coloration patterns disposed along their length. While useful, the "knit-deknit" process may be difficult to control and may be unduly time consuming and complex to enable efficient and cost effective manufacture of large quantities of material.
In order to address the deficiencies of the "knit-deknit" process, several batch-type and continuous processes have been advocated. Among the batch-type processes (in which a predetermined quantity of yarn is treated at one time), it is known to inject yarn packages with a number of different colored dyes to yield a space-dyed product. However, such batch process may be relatively costly and require more product handling than is desired.
As an alternative to the batch-type processes, several types of continuous space-dyeing processes (in which moving yarns are individually or collectively treated) are also known. One such continuous process is illustrated and described in U.S. Pat. No. 5,594,968 to Haselwander et al. the teachings of which are incorporated by reference herein. In this process yarns are intermittently pressed against dye applicator rolls to impart segments of dye to the yarns in a predetermined order. The yarn is held against the dye applicator rolls by a pattern roll supporting deflecting rods or paddles arranged in spaced relation at the surface of the pattern roll up stream of the dye applicator roll so as to provide a defined period of contact between the yarn and the dye applicator roll as the deflecting elements are pressed against the yarn at locations adjacent to the dye applicator rolls. Based upon claims made in available advertising literature, such a system is believed to permit the application of a controlled pattern of different colors to yarn having a linear density of about 500 to about 5000 denier and the length of the individual color segments achievable in such an apparatus is believed to be in the range of at least 0.5 inches (12.7 mm) or more.
U.S. Pat. Nos. 5,491,858 and 5,557,953 to Massotte et al. (incorporated by reference) disclose equipment and procedures for applying dye segments to yarns using spinning disk elements having spaced openings which permit passage of dye droplets towards the yarns when the disk openings and yarns are in opposing relation to one another. Such arrangements have been promoted as providing short color segments, but are believed to be useful only with relatively large yarns having linear densities in the range of about 720 denier and greater. As will be appreciated, such high denier materials provide an enlarged impact target area and are thus more likely to be contacted by a sufficient number of the disperse dye droplets emerging from the spinning disks to effect coloration at a desired localized position. Conversely, such disperse droplets may tend to miss smaller diameter yarns.
Another continuous process is illustrated and disclosed in U.S. Pat. No. 6,019,799 to Brown et al. the teachings of which are incorporated by reference herein. The process disclosed therein utilizes a substantially direct application of a spray pattern of dye liquor droplets towards a yarn sheet. The dye stream is cycled on and off to apply a desired patterning effect. Such a process may be useful in applying dye segments to low denier yarns but the color segments applied are relatively long being in the range of about 2 inches (50.8 mm) or greater.
In view of the above, the prior art has recognized a number of techniques for forming space-dyed yarns. However in order to obtain relatively short color segments of less than about 2 inches (50.8 mm), the yarns have been characterized by relatively high linear density ratings of 500 denier or greater. Moreover, in order to obtain color segments of less than 0.5 inches (12.7 mm), the yarns have been required to have even higher linear densities of at least about 720 denier or greater.

Apparatus and method for forming multi-colored yarn


In an insulated gate field effect semiconductor device, the gate electrode formed on the gate insulating film includes the first and second semiconductor layers as a double layer. An impurity for providing one conductivity type is not contained in first semiconductor layer which is in contact with a gate insulating film and is contained at a high concentration in the second semiconductor layer which is not in contact with the gate insulating film. Accordingly, By existence of the first semiconductor layer is which the impurity is not doped, the impurity is prevented from penetrating through the gate insulating film from the gate electrode and diffusing into the channel forming region. Also, by existence of the second semiconductor layer in which high concentration impurity is doped, the gate electrode has low resistance.

1. Field of the Invention
This invention relates to an insulated gate field effect semiconductor device using a thin film semiconductor (hereinafter referred to as a TFT) and a method for forming the insulated gate field effect semiconductor device, and particularly to a gate electrode and a method for forming the gate electrode.
2. Description of Related Art
A self-alignment type of structure has been known as a conventional TFT structure. In this structure, impurity material which provides one conductivity type is doped by an ion implantation method or the like using a gate electrode portion as a mask to form source/drain regions.
FIGS. 1A and 1B show a representative structure of this self-alignment structure of a TFT. In FIG. 1A, the structure includes an insulating substrate 21 of glass or the like, a thin film semiconductor layer 22 in which a source region 25, a channel forming region 27 and a drain region 26 are formed, a gate insulating film 23 and a gate electrode 24. Also, electrodes, layer insulating films, wirings, etc. which are well known but are not shown in FIG. 1A, are also formed in this structure.
In FIG. 1A, the semiconductor layer 22 is formed of amorphous silicon or crystallized amorphous silicon. The source region 25 and the drain region 26 are doped with phosphorus to form N-type regions. Accordingly, the TFT as shown in FIG. 1A is an N-channel type TFT. The gate insulating film 23 is formed of silicon oxide (SiO.sub.2), and the gate electrode 24 is formed of a silicon film which is doped with a large amount of phosphorus in order to reduce the resistance of the gate electrode 24.
The TFT shown in FIG. 1A is formed as follows. The amorphous silicon semiconductor layer 22 is first formed on the substrate 21 by a vapor phase method. Thereafter, the amorphous silicon semiconductor layer 22 is heated or irradiated with a laser beam in order to crystallize it, whereby the amorphous silicon semiconductor layer is transformed to crystallized silicon.
Subsequently, an oxidized silicon film serving as the gate insulating film 23 is formed by a sputtering method or the like and a silicon film doped with phosphorus, serving as the gate electrode 24, is formed by a vapor phase method or the like. Thereafter the gate insulating film 23 and the gate electrode 24 are formed in a patterning process to obtain an intermediate product having the shape shown in FIG. 1A. Subsequently, implantation (introduction) of phosphorus ions (hereinafter referred to as "ion implantation") is performed using the gate electrode 24 as a mask to form the source region 25 and the drain region 26 in a self-alignment structure. In this case, the channel forming region 27 is automatically formed.
Thereafter, through heat treatment, activation of the introduced phosphorus impurity and scratch of the semiconductor layer 22 in the ion implantation process are annealed. In this heat treatment, the gate electrode 24 formed of amorphous silicon is crystallized.
In this case, the following problem occurs.
In the heat treatment after the ion implantation process, the phosphorus diffuses from the gate electrode 24 and penetrates through the gate insulating film 23 to the channel forming region 27, as indicated by arrows 28 of FIG. 1B, so that the channel forming region 27 becomes an N-type region. As a result, the channel forming region does not function effectively, and the characteristic of the TFT deteriorates.
In order to solve the above problem, the following methods (a) to (d) may be adopted:
(a) Adoption of a doping method which requires no heat treatment, PA0 (b) Lowering the heat treatment temperature and shortening the heat treatment time, PA0 (c) Lowering the concentration of introduced phosphorus ions into the gate electrode 24, and PA0 (d) Use of a metal material requiring no ion implantation for the gate electrode.
The method (a) is not realistic because the doping system itself must be altered. That is, those devices and forming methods which are presently used cannot be utilized.
The method (b) cannot obtain various effects, such as the improvement of interface characteristics at the interface between the channel forming region 27 and the gate insulating film 23 which are obtained by heat treatment, the restoration of damage of the semiconductor layer 22 which occurs in the ion implantation process, etc., and thus does not basically solve the problem. In practical use, as a compromise, a heat treatment condition is set in a suitable permissible range in consideration of the treatment temperature and treatment time in the heat treatment process and the degree of diffusion of the impurities into the channel forming region.
The method (c) necessarily causes the resistance of the gate electrode to be increased, and this causes an increase in wiring resistance and cannot obtain the characteristics of the TFT.
In the method (d), the heat tolerance temperature of the metal material of the gate electrode 24 is an important factor in the heat treatment process after ion implantation and a subsequent protection film forming process. Therefore, the heat treatment temperature is restricted. Further, there is a problem in that although the gate electrode is not melted, the metal material of the gate electrode 24 diffuses into the channel forming region 27.
The above problems occur similarly for both N-channel type Tats and P-channel type TFTS, and are not dependent on elements introduced by ion implantation.

Insulated gate field effect semiconductor device and forming method thereof

Semiconductor Energy Laboratory Co., Ltd.


Compositions that can be used in a paper material, which may include an anionic polymer, a polyamidoamine epihalohydrin resin, and a stabilizer, are disclosed. Methods for adding the compositions to a paper material are also disclosed.

1. Field of the Art
The present embodiments relate to compositions used in paper and paper making.
2. Description of Related Art
Paper is sheet material containing interconnected small, discrete fibers. The fibers are usually formed into a sheet on a fine screen from a dilute water suspension or slurry. Paper typically is made from cellulose fibers, although occasionally synthetic fibers are used. Paper products made from untreated cellulose fibers lose their strength rapidly when they become wet, i.e., they have very little wet strength. Cationic polyamidoamine-epichlorohydrin (PAE) resins can be added to increase the wet strength of the paper. However, there is a limit to how much cationic PAE resin is absorbed onto the pulp.
The description herein of certain advantages and disadvantages of known methods and compositions is not intended to limit the scope of the present disclosure. Indeed the present embodiments may include some or all of the features described above without suffering from the same disadvantages.

Compositions used in paper and methods of making paper


A light device (10, 30) is described which comprises a first portion (12) configured so as to partially define a housing, the first portion (12) being arranged so as to at least partially pass light therethrough and the first portion (12) including first electrical contacts (46, 48) and a first locking device (50), a light emitting element (15) disposed in the first portion (12) and being electrically connected to the first electrical contacts (46, 48) and a second portion including a battery compartment (56), second electrical contacts (52, 54) arranged so as to be in electrical connection with batteries disposed in the battery compartment during use, and a second locking device (62, 64) engageable with the first locking device (50) so as to releasibly fix the second portion (13) to the first portion (12) during use and thereby close the housing. The arrangement is such that, during use, when the first and second locking devices (50, 62, 64) are engaged with each other, the first electrical contacts (50) electrically connect with the second electrical contacts (62, 64) so as to thereby electrically connect batteries disposed in the battery compartment (56) during use to the at least one light emitting element (15).

It is known to provide a light device which includes a light source in the form of one or more LEDs, batteries arranged to supply power to the LEDs, and a control unit arranged to cause the LEDs to emit light which flickers. In one such prior art light device, the LEDs are disposed inside a lantern-type housing.
However, with this arrangement, the batteries are often disposed in a lid portion of the housing and electrically connected to the LEDs in the housing. As a consequence, the task of replacing the batteries is relatively cumbersome.
It is a long standing US tradition to place candles in the windows of a home during the Christmas holiday season so that the candles are visible from outside the windows.
Due to the danger associated with an open flame, electric candle systems have evolved to take the place of traditional candles. Such electrical candles are typically supported by an inner ledge or interior sill of a double hung window, or on ledges adjacent the windows.
However, electrical candles increase household electricity costs and conventional indoor electrical candles not properly fastened or mounted can be a fire and safety hazard.
As the cost of key components used in the construction of consumer solar garden pathway lights such as solar cells, light emitting diodes, and rechargeable batteries falls, a dramatically increasing factor in the total cost of low cost solar lights to a retailer is the cost of freight, in particular since the majority of consumer solar lights are made in low cost labor countries far from their intended customers. Due to the low weight to volume ratio, freight charges for solar lights are substantially based on physical volume. Further, sales of solar lights are mostly seasonal over the summer and consequently any excess inventory requires costly long term storage.


A server transmits a message and attachments from a sender to a recipient. A hash is provided of (a) the message, (b) an identification of the sender and (c) a hash of the attachments to form a data string. Instructions may be included for the recipient to send a hashed encryption of the string to a website at the server by registered electronic mail which provides options to obtain other electronic advantages. To authenticate the message, the recipient transmits the message, the attachments and the hashed encryption of the string to the server website. The server decrypts and detaches the hashed encryption of the string to provide a first string and hashes the message, the sender identification and the hashed attachments in the first string to form a second string. The server also detaches and hashes the attachments from the message received at the server website to form first hashed attachments and detaches the hashed attachments from the string to form second hashed attachments. When the first and second hashed attachments match and the first and second strings match, the server authenticates the message to the recipient.

In recent years e-mail has become an indispensable business tool. E-mail has replaced "snail mail" for many business practices because it is faster, cheaper and generally more reliable. But there remain some mail applications where hard copy is still dominant, such as registered and certified mail. For example, when a letter is sent by certified mail the sender is provided with a receipt to prove that the letter was mailed. A returned registered mail receipt adds the Postal Service's confirmation that the letter was successfully delivered to the addressee or the addressee's authorized agent. Additionally, private couriers such as Federal Express.™ and United Parcel Service.™. (UPS) provide some type of delivery confirmation. Since every piece of courier mail is, in effect, registered, it is natural for consumers to turn to these services when they want proof of delivery.
Many existing e-mail systems and e-mail programs already provide for some form of proof of delivery. For instance, some e-mail systems today allow a sender to mark a message with "request for notifications" tags. Such tags allow a sender to request notification that the message was delivered and/or when the message was opened. When a sender requests delivery notification, the internet e-mail system may provide the sender with an e-mail receipt that the message was delivered to the mail server or electronic in-box of the recipient. The receipt message may include the title of the message, the destination address, and the time of delivery. It may also include (depending on the types of "flags" that are provided and activated in the mailing software) a list of all the internet "stations" that the message passed through en route to its destination. This form of reporting is built into some of the rules and protocols which implement e-mail. Furthermore, when a message is sent with a "read notification" request, the recipient's e-mail program may send to the sender an e-mail notification that the recipient opened that message for reading. Many electronic mail clients can and do support this kind of reporting; however, internet protocols do not make this mandatory.
However, this does not mean that an e-mail sent with a notification request is as effective in all respects as registered mail. People certify and register letters because they want proof of delivery, e.g., proof that can be used in a civil or criminal proceeding, or proof that will satisfy a supervisor or a client or a government agency that a message has been sent, a job has been done, an order placed, or a contract requirement satisfied.
A registration receipt from the United States Postal Service (USPS) constitutes proof of delivery because the USPS stands behind it. The receipt represents the Post Office's confirmation that the letter or package in question was actually delivered to the addressee or his authorized representative. On the other hand, various hurdles exist to an e-mail receipt being admitted and relied upon as persuasive evidence in a court of law as a proof that the message was delivered. After all, the receipt may be just another e-mail message that could have been altered or created by anyone, at any time.
There exists a need for an e-mail system and/or method that can provide reliable proof of the content and delivery of an e-mail message in order to take fuller advantage of the convenience and low cost of communicating via e-mail.
To meet this need some systems have been established whereby senders may receive third party proof of delivery by enrolling in services whereby:
a) The sender transmits an electronic message to a third party together with a list of the document's intended recipients.
b) The third party sends a notification to each of the message's intended recipients inviting them to visit the third party's web site where the message can be viewed.
c) If the intended recipient visits the third party's web site to view the message, the third party records this visit so that the sender may know that his message has been read by the recipient.
The drawbacks of such systems are manifold. In the first place, they rely essentially on the co-operation of the recipient of the e-mail to collect his or her messages from the third party's service. But the circumstances in which a sender may want proof of delivery of a message are often ones in which it cannot be assumed that the intended recipient will co-operate in receiving the message. In such cases, e.g. where acknowledging receipt of the message would place a financial or legal burden on the recipient, the recipient can simply ignore the notification that mail is available for him to receive. Note that there is nothing in such a system to guarantee that the intended recipient has received notification of waiting mail. In the second place, such systems are cumbersome and slow to use as compared to regular e-mail insofar as it can require the sender and/or the recipient to connect to a World Wide Web site to send, collect and verify the delivery of each message. Moreover, transmission of documents by such methods may require both sender and receiver to upload and download files to a web site. Finally, because these methods require the third party to retain a copy of the whole of each message until such time as they are collected or expired, the methods can require its provider to devote substantial computational resources to data storage and data tracking over an extended period of time. As an alternative method of providing proof of delivery, some systems provide proprietary e-mail clients or web-browser plug-ins that will notify senders when a message has been received provided that a recipient uses the same e-mail client. The obvious disadvantage of such systems is that they require both sender and recipient to use the same e-mail client.
Therefore, there exists a need for an e-mail system/method that (1) can provide reliable proof of the content and delivery of electronic messages, (2) which does not require the compliance or co-operation of the recipient, (3) requires no special e-mail software on the part of sender or recipient, (4) operates with the same or nearly the same convenience and speed of use as conventional e-mail, and (5) can be operated economically by a service provider.
In co-pending application Ser. No. 09/626,577, filed by Dr. Terrance A. Tomkow and assigned of record to the assignee of record of this application, a system and method are disclosed and claimed for reliably verifying via secure and tamper-proof documentation the content and delivery of an electronic message such as an e-mail. Ideally, the invention disclosed and claimed in co-pending application Ser. No. 09/626,577 will give e-mail and other electronic messages a legal status on a par with, if not superior to, that of registered United States mail. However, it is not necessary to the invention that any particular legal status is accorded to messages sent according to the methods taught in co-pending application Ser. No. 09/626,577, as the invention provides useful information and verification regardless.
The invention disclosed and claimed in co-pending application Ser. No. 09/626,577 includes an electronic message system that creates and records a digital signature of each electronic message sent through the system. An originator may send a copy of the electronic message to the system or generate the electronic message within the system itself. The system then forwards and delivers the electronic message to all recipients (or to the designated message handlers associated with the recipients), including "to" addressees and "cc" addressees. Thereafter, the system returns a receipt of delivery to the originator of the electronic message. The receipt includes, among other things: the original message, the digital signature of the message, and a handshaking and delivery history including times of delivery to the recipients and a digital signature of the handshaking and delivery history. To later verify and authenticate information contained in the receipt, the originator or user sends a copy of the message, the digital signature of the message and the receipt to the system. The system then verifies that the digital signature is the digital signature of the original message. The system then sends a letter or provides other confirmation of authenticity verifying that the electronic message has not been altered.
The receipt may also include a digital signature of the handshaking and delivery history. The system may verify that this digital signature is a digital signature of the handshaking and delivery history. This provides a further verification that the message has not been altered.
The system disclosed and claimed in co-pending application Ser. No. 09/626,577 may include a form of e-mail server connected to the internet, which can be utilized in many ways. For instance, individual users can register their electronic messages, such as e-mails, by sending a "carbon copy" ("cc:") to the system or composing the message within the system itself. For corporate or e-commerce users, these users can change their server to a server incorporating the present invention and have all of their external electronic messages registered, with the option of having the system retain and archive the receipts. The system can accept and verify encrypted electronic messages and manage the electronic messages within and/or outside a "fire wall." For web-based users, i.e., individuals or corporations using web-based e-mails, such as MSN Hotmail.™. or Yahoo Mail.™., such users could check a box or otherwise set a flag within their e-mail programs to select on a case-by-case basis whether to make the e-mails of record and/or to archive the messages using the system disclosed and claimed in co-pending application Ser. No. 09/626,577.
The digital signature can be created using known digital signature techniques, such as by performing a hash function on the message to produce a message digest and then encrypting the message digest. Separate digital signatures can be created for the body of the message, any attachments, and for the overall message including the body, the attachments, and the individual message digests. The encrypted message digest provides one type of message authentication or validation code, or secure documentation. Other message authentication and/or validation codes may also be generated and used.
In one aspect, the invention disclosed and claimed in co-pending application Ser. No. 09/626,577 is a method of providing proof regarding the delivery and content of an electronic message, comprising: receiving from a sender across a computer network an electronic message, the message having a delivery address associated therewith; computing a message digest according to the message; encrypting the message digest; sending the message electronically to a destination corresponding to the delivery address; recording the Simple Mail Transport Protocol (SMTP) or Extended SMTP (ESMTP) dialog which effects the delivery of the message; receiving Delivery Status Notification information associated with the message and the delivery address; providing to the sender an electronic receipt, the receipt comprising: a copy of the message, the encrypted message digest, the (E)SMTP transcripts, and at least a subset of the Delivery Status notification information, and, at a future date, receiving electronically the electronic receipt from the sender, verifying that the encrypted message digest corresponds to the message, and verifying that the message was received by an electronic message handler associated with the delivery address.
In another aspect, the invention disclosed and claimed in co-pending application Ser. No. 09/626,577 includes a method of verifying delivery of an electronic message, comprising: in a wide area network computer system, receiving an electronic message from a message sender for routing to a destination address; establishing communication with an electronic message server associated with the destination address, the server defining a destination server; querying the destination server to determine whether the destination server supports Delivery Status Notification (DSN) functionality; receiving a response to the query, the query and response together defining an SMTP dialog; requesting Delivery Status notification information from the destination server according to results of the SMTP dialog; transmitting the electronic message to the destination address; receiving DSN information from the destination server with respect to delivery of the electronic message; and providing to the message sender at least a portion of the SMTP dialog, and at least a portion of the DSN information.
In yet another aspect, the invention disclosed and claimed in co-pending application Ser. No. 09/626,577 includes a method of verifying content of a received electronic message, comprising: receiving the electronic message; generating a digital signature corresponding to the content of the received message; providing the message and the digital signature to a designated addressee; and, at a later time, verifying that the digital signature is the digital signature of the message.
In accordance with still another aspect of the invention disclosed and claimed in co-pending application Ser. No. 09/626,577, the method includes establishing whether a message was electronically received by a recipient, comprising: providing a message to be dispatched electronically along with a recipient's address from a sender; creating a signature associated with the message; dispatching the message electronically to the recipient's address; tracking the message to determine a final Delivery Status of the message dispatched to the recipient's address; upon receiving final Delivery Status of the message, generating a receipt, the receipt including a copy of the message, the signature, and the final Delivery Status for the message; and providing the receipt to the sender for later establishing that the message was electronically received by the recipient.
In accordance with yet another aspect of the invention disclosed and claimed in co-pending application Ser. No. 09/626,577, a method is provided for proving that an electronic message sent to a recipient was read, comprising: providing an electronic message along with a recipient's address; calculating a digital signature corresponding to the electronic message; dispatching the electronic message electronically to the recipient's address; requesting a Mail User Agent (email client "reading") notification from the recipient; upon receiving the reading notification, generating a reading receipt, the reading receipt including a copy of the message, the digital signature for the corresponding electronic message, and a second digital signature for the reading receipt from the recipient; and providing the reading receipt for later verification that said message was received by the recipient.
The verification discussed in the previous paragraph may be provided by hashing the message to provide a first digital fingerprint and decrypting the digital signature of the message to provide a second digital fingerprint and by comparing the two digital fingerprints. The verification discussed in the previous paragraph may be further provided by hashing the reading receipt from the recipient to provide a third digital fingerprint, by decrypting the digital signature of the reading recipient from the recipient to provide a fourth digital fingerprint and by comparing the third and fourth digital fingerprints.
In accordance with another aspect of the invention disclosed and claimed in co-pending application Ser. No. 09/626,577, a method is provided for validating the integrity of a purported copy of an electronic message, comprising: receiving the purported electronic message copy, said purported copy including an encrypted message digest associated therewith; decrypting the encrypted message digest; generating a second message digest based on content of the purported copy; and validating the purported copy by comparing the decrypted message digest and the second message digest to determine whether the two message digests match.
In accordance with a still further aspect of the invention disclosed and claimed in co-pending application Ser. No. 09/626,577, a method is provided for validating a received REGISTERED E-MAIL, comprising: receiving an electronic receipt, said receipt including a base message and an encrypted message digest; decrypting the encrypted message digest; generating a second message digest from the base message; and validating the e-mail if the decrypted message digest matches the second message digest.
In yet another aspect, the invention disclosed and claimed in co-pending application Ser. No. 09/626,577 includes a website at which users can go to send and receive secure messages, with the website host acting as an independent third party which will send and receive the messages and provide secure documentation regarding the content and delivery of the messages.
In co-pending application Ser. No. 09/626,577, an authentication of a message provided by a sender to a server and sent by the server to a recipient is provided by the server to the sender. In one embodiment, the server transmits the message to a recipient. The message may pass through intermediate stations before it reaches the recipient. These intermediate stations and the times of the transmission to these intermediate stations are recorded. Other intermediate stations between the recipient and the server provide a record of their operations and the time of their operations in passing all of the information relating to the transmission of the message from the server to the recipient and relating to the transmission of the recipient of the message.
In co-pending application Ser. No. 09/626,577, a server transmits a message from a sender to a recipient. The message may pass through intermediate stations before it reaches the recipient. These intermediate stations, and the time for the transmission of the message to the intermediate stations form a part of the record received at the intermediate station. The intermediate stations receiving this record in the transmission of the record from the recipient, and the times for the transmission of the record to the intermediate stations, are also included in the record received at the server. The server then transmits to the sender this record, the message, the digital signature of the message and the digital signature of the attachment(s) defined by the record(s) of the intermediate stations and the times of the transmissions to the intermediate stations.
When the sender wishes to authenticate the message and the file history of the transmission of the message between the sender and the recipient, the sender transmits this information to the server and the server processes this information to provide the authentication.
Generally the server is hired by the sender to act as the sender's agent in transmitting a message electronically to a recipient. Since the server acts as the sender's agent, the sender is interested in authenticating that the server has transmitted the message properly to the recipient and in authenticating the time of transmission of the message to the recipient. The system and method disclosed and claimed in co-pending application Ser. No. 09/626,577 provides these authentications.
Sometimes the recipient is interested in authenticating the message transmitted to the recipient and in authenticating the time of the transmission of the message to the recipient. For example, this is important when the sender is a United States or state court, and the recipient is an attorney involved in representing a client in a matter before the courts and the message relates to a document that the attorney has to file on a short time basis in the court. Under such circumstances, the attorney may wish to have the message authenticated promptly and the time of the transmission of the message to the attorney authenticated promptly. As will be appreciated, any system of method addressing this problem should be simple, prompt and reliable.
The mostly widely practiced methods for authenticating the authorship and content of electronic messages involve applications of Public Key Cryptography. In such methods the sender of the message computes a digital digest or "hash" of the contents of the message and encrypts this information, together with other information identifying the sender, using the sender's private encryption key. The encrypted information is included as an attachment to the message. Upon receiving the message the recipient authenticates its authorship and content by applying the sender's public encryption key to decrypt the attachment and then compares the decrypted digital digest with a digital digest of the received message.
There are several shortcomings with this system:
The system requires that the recipient possesses software capable of performing the necessary cryptography and possesses the requisite decryption keys. Some of the most commonly used mail clients, e.g., web based mail client, lack this capacity. The method is not universal among e-mail clients.
When a message is "digitally signed" in this manner any change to the message however innocent will result in a failure to authenticate. For example, the changes typically introduced into a message by forwarding it from most e-mail clients will change the message's digest and will result in a failure to authenticate. PKI digital signatures are, in this sense, fragile.
Finally, when a message fails to authenticate because it has changed, it is for all practical purposes, impossible for the recipient to know which portion of the message has changed or to reconstruct the original message. The method is not resilient.
In contrast the method described below is universal, non-fragile, and resilient.

System for, and method of, providing the transmission, receipt and content of an e-mail message


A method for estimating video quality on bit-stream level, wherein the video quality refers to a video after error concealment and the method is performed on bit-stream level before said error concealment, comprises extracting and/or calculating a plurality of global condition features from a video bit-stream, extracting and/or calculating a plurality of local effectiveness features at least for a lost MB, calculating a numeric error concealment effectiveness level for each (or at least for each lost) MB by emulating an error concealment method that is used in said error concealment, and providing the calculated error concealment effectiveness level as an estimated visible artifacts level of video quality.

This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Video delivery over IP network is unreliable. A requirement for VQM (video quality modeling) is to rate the quality degradation caused by IP transmission impairment (e.g. packet loss, delay, jitter), in addition to those caused by video compression. The artifacts are evaluated after applying error concealment (EC) at the decoder, since the result should relate to the video quality perceived by a viewer. The goal of EC is to estimate missing macroblocks (MBs) that arise from bit-erasure or packet loss, in order to provide a minimum degree of perceptual quality degradation. Thus, accurate prediction of the EC effectiveness is a fundamental part of VQM measuring transmission impairment.
EC methods are either spatial (i.e., bilinear interpolation, mainly for I-frames) or temporal (i.e., estimation of lost motion vectors (MV), mainly for B- and P-frames). VQM technologies can be categorized into packet-layer model, bitstream-level model, media level model and hybrid model. ITU-T SG12/Q14 considers a bitstream-level no-reference video quality (VQ) assessment model to predict the impact of observed coding and IP network impairments on quality in mobile streaming and IPTV applications. It predicts a Mean Opinion Score (MOS) using the bitstream information, and information contained in packet headers, prior knowledge about the media stream and buffering information from the client. H. Rui, C. Li, and S. Qiu in "Evaluation of packet loss impairment on streaming video", J. Zhejiang Univ.-Sci. A, Vol. 7, pp. 131-136 (January 2006) propose a VQM model that uses strong spatial discontinuities as hints of packet loss, and is based on decoded pixel information. However, this information is not available on bitstream-level.
T. Yamada, Y. Miyamoto, and M. Serizawa in "No-reference video quality estimation based on error-concealment effectiveness", Packet Video, 288-293, (2007) describe a no-reference hybrid VQM using both bitstream-level information and the decoded pixel information. It maps the number of MBs for which the error concealment is determined as ineffective to a MOS value.
A problem with the above methods is that they do not work well when a lost MB is not stationary, which happens quite often in realistic video sequences.
A. R. Reibman, V. A. Vaishampayan and Y. Sermadevi in "Quality monitoring of video over a packet network", IEEE Transactions on Multimedia, 6(2), 327-334, (2004) use a no-reference bitstream-level VQM to estimate MSE (Mean Squared Error) of an EC video sequence in case of transmission impairment. Estimates of some statistical parameters from the received video bitstream on a macroblock basis (such as DC and AC components of DCT of I-frame MBs, the motion vectors of P- and B-MBs) are used. One problem of this model is that it uses MSE (mean squared error) as target visual quality metric, instead of the subjective MOS. It is well known that MSE is not a good metric for subjective video quality, especially for measuring quality degradation caused by transmission impairment.

Method and device for estimating video quality on bitstream level


The invention encompasses the novel compound of Formula I as well as a method of treating COX-2 mediated diseases comprising administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of Formula I. ##STR1## The invention also encompasses certain pharmaceutical compositions for treatment of COX-2 mediated diseases comprising compounds of Formula I.

This invention relates to methods of treating cyclooxygenase mediated diseases and certain pharmaceutical compositions therefor.
Non-steroidal, antiinflammatory drugs exert most of their antiinflammatory, analgesic and antipyretic activity and inhibit hormone-induced uterine contractions and certain types of cancer growth through inhibition of prostaglandin G/H synthase, also known as cyclooxygenase. Initially, only one form of cyclooxygenase was known, this corresponding to cyclooxygenase-1 (COX-1) or the constitutive enzyme, as originally identified in bovine seminal vesicles. More recently the gene for a second inducible form of cyclooxygenase, cyclooxygenase-2 (COX-2) has been cloned, sequenced and characterized initially from chicken, murine and human sources. This enzyme is distinct from the COX- 1 which has been cloned, sequenced and characterized from various sources including the sheep, the mouse and man. The second form of cyclooxygenase, COX-2, is rapidly and readily inducible by a number of agents including mitogens, endotoxin, hormones, cytokines and growth factors. As prostaglandins have both physiological and pathological roles, we have concluded that the constitutive enzyme, COX-1, is responsible, in large part, for endogenous basal release of prostaglandins and hence is important in their physiological functions such as the maintenance of gastrointestinal integrity and renal blood flow. In contrast, we have concluded that the inducible form, COX-2, is mainly responsible for the pathological effects of prostaglandins where rapid induction of the enzyme would occur in response to such agents as inflammatory agents, hormones, growth factors, and cytokines. Thus, a selective inhibitor of COX-2 will have similar antiinflammatory, antipyretic and analgesic properties to a conventional non-steroidal antiinflammatory drug, and in addition would inhibit hormone-induced uterine contractions and have potential anti-cancer effects, but will have a diminished ability to induce some of the mechanism-based side effects. In particular, such a compound should have a reduced potential for gastrointestinal toxicity, a reduced potential for renal side effects, a reduced effect on bleeding times and possibly a lessened ability to induce asthma attacks in aspirin-sensitive asthmatic subjects.
Furthermore, such a compound will also inhibit prostanoid-induced smooth muscle contraction by preventing the synthesis of contractile prostanoids and hence may be of use in the treatment of dysmenorrhea, premature labour, asthma and eosinophil related disorders. It will also be of use in the treatment of Alzheimer's disease, for decreasing bone loss particularly in postmenopausal women (i.e. treatment of osteoporosis) and for the treatment of glaucoma.
The potential utilities of selective cyclooxygenase-2 inhibitors are discussed in the following articles:
1. John Vane, "Towards a better aspirin" in Nature, Vol. 367, pp. 215-216, 1994. PA1 2. Bruno Battistini, Regina Botting and Y. S. Bakhle, COX-1 and COX-2: Toward the Development of More Selective NSAIDs" in Drug News and Perspectives, Vol. 7, pp. 501-512, 1994. PA1 3. David B. Reitz and Karen Seibert, "Selective Cyclooxygenase Inhibitors" in Annual Reports in Medicinal Chemistry, James A. Bristol, Editor, Vol. 30, pp. 179-188, 1995. PA1 4. Don E. Griswold and Jerry L. Adams, "Constituative Cyclooxygenase (COX-1) and Inducible Cyclooxygenase (COX-2): Rationale for Selective Inhibition and Progress to Date" in Medicinal Research Reviews, Vol. 16, pp. 181-206, 1996. PA1 Ar is a mono-, di-, or trisubstituted phenyl or pyridinyl (or the N-oxide thereof), wherein the substituents are chosen from the group consisting of PA1 R.sup.2 is chosen from the group consisting of PA1 R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, are each independantly chosen from the group consisting of PA1 or R.sup.4 and R.sup.5, R.sup.8 and R.sup.9 or R.sup.11 and R.sup.12 together with the atom to which they are attached form a saturated monocyclic ring of 3, 4, 5, 6 or 7 atoms. PA1 (a) hydrogen, PA1 (b) halo, PA1 (c) C.sub.1-4 alkoxy, PA1 (d) C.sub.1-4 alkylthio, PA1 (e) C.sub.1-4 alkyl, PA1 (f) CF.sub.3, and PA1 (g) CN. PA1 Ar is a mono-, di-, or trisubstituted pyridinyl (or the N-oxide thereof), wherein the substituents are chosen from the group consisting of PA1 R.sup.2 is chosen from the group consisting of PA1 R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.11, R.sup.12, R.sup.13, are each independantly chosen from the group consisting of PA1 or R.sup.4 and R.sup.5 or R.sup.11 and R.sup.12 together with the atom to which they are attached form a saturated monocyclic ring of 3, 4, 5, 6 or 7 atoms. PA1 R.sup.2 is chosen from the group consisting of PA1 and wherein there may be one, two or three groups X independently selected from the group consisting of PA1 R.sup.2 is chloro, PA1 wherein there is one group X independently selected from the group consisting of PA1 R.sup.2 is chloro, PA1 wherein there is one group X independently selected from the group consisting of PA1 3-(4-Methylsulfonyl)phenyl-2-phenyl-5-trifluoromethylpyridine; PA1 2-(3-Chlorophenyl)-3-(4-methylsulfonyl)phenyl-5-trifluoromethyl-pyridine; PA1 2-(4-Chlorophenyl)-3-(4-methylsulfonyl)phenyl-5-trifluoromethyl-pyridine; PA1 2-(4-Fluorophenyl)-3-(4-methylsulfonyl)phenyl-5-trifluoromethyl-pyridine; PA1 3-(4-Methylsulfonyl)phenyl-2-(3-pyridinyl)-5-trifluoromethylpyridine; PA1 5-Methyl-3-(4-methylsulfonyl)phenyl-2-phenylpyridine; PA1 2-(4-Chlorophenyl)-5-methyl-3-(4-methylsulfonyl) phenylpyridine; PA1 5-Methyl-3-(4-methylsulfonyl)phenyl-2-(3-pyridinyl) pyridine; PA1 5-Chloro-2-(4-chlorophenyl)-3-(4-methylsulfonyl) phenylpyridine; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(2-pyridinyl) pyridine; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(3-pyridinyl) pyridine; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(4-pyridinyl) pyridine; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(2-methyl-5-pyridinyl)pyridine; PA1 2-(4-Chlorophenyl)-3-(4-methylsulfonyl)phenylpyridinyl-5-carboxylic acid methyl ester; PA1 2-(4-Chlorophenyl)-3-(4-methylsulfonyl)phenylpyridinyl-5-carboxylic acid; PA1 5-Cyano-2-(4-chlorophenyl)-3-(4-methylsulfonyl) phenylpyridine; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(3-pyridyl)pyridine hydromethanesulfonate; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(3-pyridyl)pyridine hydrochloride; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(2-methyl-5-pyridinyl)pyridine Hydrochloride; PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(2-ethyl-5-pyridinyl)pyridine; and PA1 5-Chloro-3-(4-methylsulfonyl)phenyl-2-(2-ethyl-5-pyridinyl)pyridine hydromethanesulfonate. PA1 a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier. PA1 a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier. PA1 administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of formula I and a pharmaceutically acceptable carrier. PA1 administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of formula I. PA1 AA=arachidonic acid PA1 Ac=acetyl PA1 AIBN=2.2.sup.- -azobisisobutyronitrile PA1 BHT=butylated hydroxytoluene PA1 Bn=benzyl PA1 CSA=camphor sulfonic acid (racemic) PA1 dba=dibenzylideneacetone PA1 DMAP=4-(dimethylamino)pyridine PA1 DMF=N,N-dimethylformamide PA1 DMSO=dimethyl sulfoxide PA1 EDTA=ethylenediaminetetraacetic acid PA1 ESA=ethane sulfonic acid PA1 Et.sub.3 N=triethylamine PA1 HBSS=Hanks balanced salt solution PA1 HEPES=N-2-Hydroxyethyl!piperazine-N.sup.1 -2-ethanesulfonic acid! PA1 HWB=human whole blood PA1 KHMDS=potassium hexamethyldisilazane PA1 LDA=lithium diisopropylamide PA1 LPS=lipopolysaccharide PA1 mCPBA=m-chloroperbenzoic acid PA1 MMPP=magnesium monoperoxyphthalate PA1 Ms=methanesulfonyl=mesyl PA1 MsO=methanesulfonate=mesylate PA1 MTBE=methyl tert-butyl ether PA1 NBS=N-bromosuccinimide PA1 NCS=N-chlorosuccinimide PA1 NIS=N-iodosuccinimide PA1 NMO=N-methylmorpholine-N-oxide PA1 NMP=N-methylpyrrolidone PA1 NSAID=non-steroidal anti-inflammatory drug PA1 oxone.RTM.=2KHSO.sub.5.KHSO.sub.4.K.sub.2 SO.sub.4 PA1 PCC=pyridinium chlorochromate PA1 PDC=pyridinium dichromate PA1 PEG=polyethyleneglycol PA1 Ph=phenyl PA1 pyr=pyridinyl PA1 r.t.=room temperature PA1 rac.=racemic PA1 Tf=trifluoromethanesulfonyl=triflyl PA1 TfO=trifluoromethanesulfonate=triflate PA1 THF=tetrahydrofuran PA1 TLC=thin layer chromatography PA1 Ts=p-toluenesulfonyl=tosyl PA1 TsO=p-toluenesulfonate=tosylate PA1 Tz=1 H (or 2 H)-tetrazol-5-yl PA1 SO.sub.2 Me=methyl sulfone PA1 SO.sub.2 NH.sub.2 =sulfonamide PA1 Me=methyl PA1 Et=ethyl PA1 n-Pr=normal propyl PA1 i-Pr=isopropyl PA1 n-Bu=normal butyl PA1 i-Bu=isobutyl PA1 s-Bu=secondary butyl PA1 t-Bu=tertiary butyl PA1 c-Pr=cyclopropyl PA1 c-Bu=cyclobutyl PA1 c-Pen=cyclopentyl PA1 c-Hex=cyclohexyl PA1 bid=bis in die=twice daily PA1 qid=quater in die=four times a day PA1 tid=ter in die=three times a day PA1 administration to a patient in need of such treatment of a non-toxic therapeutically effective amount of a compound of Formula I as disclosed herein.
WO 96/10012 (DuPont Merck, Apr. 4, 1996) discloses compounds represented by Formula A as being useful in the treatment of COX-2 mediated diseases, by virtue of their selective inhibition of COX-2 rather than COX-1. We have now discovered that a subset of the compounds represented by A, in which --J--K--L-- is --NCHCH--, X is a bond, R.sup.1 is aromatic and R.sup.3 and R.sup.4 are not both hydrogen show unexpectedly superior selectivity for the inhibition of COX-2 over COX-1 and/or superior potency as compared to the closest species disclosed in 96/10012. This subset of compounds is the subject of the present invention and is represented by Formula I. ##STR2##
Of the over 175 specific compounds disclosed in WO 96/10012, only 4 of them are pyridines, and none of these latter contain a substituent (R.sup.3 or R.sup.4 in A) on the pyridine ring.
WO 96/16934 (Searle, Jun. 6, 1996) discloses compounds represented by structure B as being useful for the treatment of inflammation and related disorders. Chemically, these compounds differ from those of the present invention in that the central of the three aromatic rings is benzene rather than pyridine.

Substituted pyridines as selective cyclooxygenase-2 inhibitors


A wireless communications device has a transponder for transmitting information for making a transaction to a point of sale terminal. When the device is within the range of a field generated by the point of sale terminal, the transponder is excited and transmits the information to the point of sale terminal. The wireless communications device also includes a cellular transmitter for use in making a purchase transaction.

1. Field of the Invention
The present invention is directed to a system, method and device for performing transactions, such as financial transactions, via a communications link. More particularly, the present invention is directed to a system, method and device for performing financial transactions, such as sales transactions at a point of sale terminal, via a wireless communications link. Still more specifically, the present invention is directed to utilization of a hand held electronic device, such as a cellular telephone, a pager, or a hand held personal computer, for performing financial transactions and, particularly, sales transactions via a wireless communications link.
2. Description of the Related Art
The popularity of cashless transactions is widespread. In this regard, a substantial quantity of transactions are made everyday by consumers utilizing credit or debit cards. As is known, these cards typically employ a magnetic strip having data indicative of the account holder and corresponding account thereon. The cards are passed through a reader connected to a point of sale terminal, and an appropriate number of monetary units corresponding to the transaction being made are either credited to, or debited from, the account corresponding to the card.
More recently, "Smart Cards" have been proposed, and have gained some popularity. Unlike conventional debit and credit cards, which are typically passive devices, Smart Cards are stored-value products in that the card maintains a "stored value" of funds available to the consumer for access primarily at retail locations. The "stored value" is typically stored on a computer chip within the card, or possibly on a magnetic strip. The card is considered "smart", because the stored value may be added to, such as at an automatic teller machine, and may be subtracted from, such as the case when a balance recorded on the card is debited at a merchant's POS terminal when the consumer makes a purchase.
The most sophisticated systems currently available permit consumers to store substantial amounts of "e-cash" on the card. Some Smart Cards allow the consumer to obtain additional cash from ATMs in addition to making purchases. Some also have a feature by which the consumer can "load up" by accessing a line of credit. Depending upon the type of Smart Card utilized, one purported advantage of Smart Cards is that they can operate like cash in that there is no requirement for accessing a central facility, storing and retrieving data from the central facility, or storing a record to the central facility.
While each of the foregoing types of electronic cash, debit, and credit products are useful for their intended purposes, each has drawbacks. For instance, credit, debit, and Smart Cards are issued by a particular financial institution or a vendor. While the cards may be utilized at a wide variety of merchant locations, the consumer has no choice of which account he or she wishes to correspond with a transaction, unless the consumer has multiple such cards. Additionally, each of the foregoing types of cards is limited to its particular purpose, and is not usable for any other function.
In addition to the widespread and increasing popularity of various types of bank cards and Smart cards, the proliferation of wireless communication devices has been widespread in recent years. In this regard, cellular telephones, pagers, and hand or palm held personal computers have gained widespread popularity. The devices are useful not only for transmitting and receiving voice and data, but also for storing information, such as addresses, telephone numbers, etc. depending upon the particular features and function of the device. In short, however, the number of users and the volume of use of such products is substantial and growing rapidly.
In spite of the widespread use and popularity of cellular telephones, pagers, and hand held computers, these products have not previously been used for making financial transactions and, particularly, for transacting sales at merchants point of sale terminals. In this regard, conventional point of sale terminals are not equipped to communicate with a wireless communication device. There have been some attempts at combining Smart Cards and Smart Card readers with wireless communication devices. For example, U.S. Pat. No. 5,890,052 is directed to a portable wireless telephone structure in which a foldable wallet carries a telephone, in addition to having a pocket to house paper currency. The telephone may be utilized to transfer money from a bank account to the Smart Card. Thus, according to the patent, apart from storage of bank notes as required by the user, the only additional bulk required with the structure is a single Smart Card for use with the telephone for transaction purposes. U.S. Pat. No. 5,796,832 is directed to a wireless transaction information system which permits a wireless or cellular telephone hook up to a financial institution. A particular feature of the invention is that a "Smart Card" is utilized to verify authorization for banking transactions, or to maintain a secure record of available funds.
The inventions disclosed in the foregoing patents have not gained widespread popularity, primarily due to the fact that Smart Cards themselves have not gained overwhelming popularity. Moreover, neither patent provides a user the ability to perform sales transactions at a point of sale terminal using a wireless communication device.
Even more recently, proposals have been made to include Internet browser software in cellular telephones, for allowing a user of a cellular telephone device to browse the Internet via a wireless communications link. These proposals, however, are directed at permitting the user of a cellular telephone to browse the Internet for information, but do not address the need to make financial transactions utilizing the cellular telephone. Other recent proposals involve using a cellular telephone to remotely control home appliances in so-called "smart" houses. Again, these proposals do not address using the cellular telephone to make sales transactions.
Accordingly, in view of the overwhelming popularity of electronic transactions and wireless communication devices, the need exists for a method, system and device for performing sales transactions at a point of sale terminal via a wireless link from a wireless communication device, such as a cellular telephone, pager, or hand held personal computer. The present invention fills these and other needs, while overcoming the drawbacks of the prior art.

Device for making a transaction via a communications link


A lathe for processing a workpiece into a nonaxisymmetric shape including a cutter to be always contacted with a workpiece surface at an almost fixed angle. A first support shaft is rotatably supported around a first axis mounted on a tool rest, and a second support shaft is rotatably supported around a second axis mounted on and off-centered from the first axis. Also, a third support shaft is rotatably supported around a third axis mounted on and off-centered from the second axis, and a holder for holding the cutter is secured to one end of the third support shaft. A controller controls the rotating angles of the support shafts to control the movement of the cutter forwards and rearwards and also its contact angle.

The present invention relates to a lathe for processing a workpiece into a nonaxisymmetric shape such as a cam shape or the like.
A conventional NC (numerically controlled) cam cutting lathe includes a head stock for holding a workpiece and a tool rest for holding a turning tool or bit for cutting the workpiece. Usually, the workpiece has a round bar shape before cutting and one end of this round bar is secured to a spindle mounted on the head stock. On cutting, the spindle is rotated around an axis of the workpiece and the tool rest is slidably moved in the direction of the axis of the workpiece and in the direction perpendicular to the moving direction of the head stock. The knife edge of the bit held on the tool rest is contacted with the side surface of the workpiece so as to cut it. As the tool rest is moved in the moving direction, the contact point of the bit with respect to the workpiece is successively axially move to enable a cutting of the workpiece in a predetermined area in the axis direction of the workpiece. Also, by moving the tool rest towards the workpiece, the contact point of the bit with the workpiece is successively moved in the cutting direction deeper into the interior to carry out deeper cutting.
The above-described lathe structure is the same as a usual lathe. However, in this lathe, the distance from the rotary center to the workpiece surface in the workpiece is not fixed in the radial direction, and thus it is required to move the bit forwards or backwards in the cutting direction in correspondence to the cam shape in synchronism with the rotation of the workpiece. That is, in the lathe for cutting the cam, a driving mechanism or a feeding mechanism for moving the bit forwards or backwards in synchronism with the rotation period of the workpiece is required. In particular, with the increase of the rotation speed of the workpiece for reducing the machining time, the moving of the tool at a quick speed is required.
Accordingly, it is necessary to move the heavy tool rest at high speed, and the tool rest and its sliding saddle surface of a bed are worn. Also, a screw surface of a feeding screw of the feeding mechanism is partially worn at only a frequently used part.
Further, when the tool rest is changed from the rearward movement to the frontward movement and vice versa, the moving direction of the tool rest is suddenly changed and a large shock is given to the feeding mechanism of the tool rest. This large shock often breaks parts of the feeding mechanism or at least deteriorates the accuracy of the same.
In the conventional lathe, in order to avoid the above-described problems, the cutting speed, that is, the workpiece rotation speed, is required to be low.
Also, since the bit is secured to the tool rest, the rotation axis of the workpiece, that is, the angle with respect to the spindle, is fixed. However, regarding the workpiece, the distance (radius) from the rotation axis to the workpiece surface is not equal in the radial direction. Hence, in the cam cutting, the contact angle of the bit with the cam surface is not fixed and is always varied. Particularly, at the large cam radius change part, the bit contact angle is substantially changed. Thus, with the change of the contact angle of the bit, the angle (effective rake angle) of the cutting face of the bit with respect to the cutting surface of the workpiece is changed. This effective rake angle gives a large influence to a cutting force at the cutting time and, with the change of the effective rake angle, the cutting force is changed.
That is, as shown in FIG. 14, when a workpiece 110 is cut into a nonaxisymmetric shape, by only a frontward or rearward movement, that is, an X-direction movement of a tool or cutter 114, a contact angle (rake angle) a of the cutter 114 with respect to the workpiece 110 is always varied depending on the cutting position. When this rake angle a is changed, a shear angle b of a tip 113 is changed. A size of a sliding surface 113a of the tip 113 is changed and thus the cutting force is changed. As described above, changing the effective rake angle to shift out of a design value creates a bad influence on the smoothness of the cutting surface, and the smoothness required to a finish surface can not be satisfied.
Further, in order to avoid a contact of the rear surface of the bit with the cutting surface, as shown in FIG. 13, it is necessary to also increase a clearance angle c of a bit 114. Hence, an included angle e becomes small and a knife strength is drastically reduced.


A grip device for moving a front floor of a vehicle includes a front clamping member and a rear clamping member. The front claming member can clamp a flange portion around a suspension mounting hole of the front floor according to an angle of the flange portion. The rear clamping member can claim a member flange portion of the front floor according to the change of clamping position. The device can be applied to various vehicle models.

(a) Technical Field
The present invention relates to a grip device for moving a front floor of a vehicle, which can be applied regardless of a kind of vehicle.
(b) Background Art
In general, a grip device for moving a front floor is mounted to a robot in a vehicle body production line so as to grip and move a front floor of a vehicle from one production line to another production line or fix the front floor in a position for performing a sealer coating using a gun.
In a prior art grip device for moving a front floor, a flange portion around a suspension mounting hole of the front floor and a member flange portion are clamped by respective clampers.
The prior art grip device, however, has a drawback. In particular, as the size and cross-sectional shape of front floor parts, the angle and clamping spot of the flange portion around the suspension mounting hole, and the clamping spot of the member flange portion vary depending on types of vehicles, different grip devices have to be manufactured for different vehicle models, which increases overall manufacturing costs.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.


A finely particulate polymer for use in a stencil ink is disclosed which is uniformly dispersible into a binder polymer having a solubility parameter of 11.0 or lower and has an average particle diameter of from 0.1 to 10 .mu.m and a maximum particle diameter of 50 .mu.m or smaller. The finely particulate polymer is highly advantageous in that stencil inks having an appropriate viscosity can be easily obtained with the particulate polymer using the same formulation even when the inks contain different colorants, and that with the particulate polymer, a colorant which has been unusable due to its adverse influence on the storage stability of stencil inks can be used to produce a stencil ink having excellent storage stability by encapsulating the colorant in the individual polymer particles.

Stencil printing is a printing process which can be easily carried out and has been extensively used from old times. As a result of the automation of stencil preparation and printing operation in stencil printing in recent years, this printing process has become more convenient and has come to be widely used in new applications. For this stencil printing, W/O emulsion inks have been mostly used from the standpoints of printability and machine operation. Such inks are usually produced by kneading a colorant (coloring material) together with a resin and adding water thereto.
However, formulations should be varied according to colorants in order to impart satisfactory storage stability to the inks, and much labor has been required for making particular formulations suitable for obtaining satisfactory inks. Since the storage stability of emulsion inks varies considerably depending on the chemical properties of individual colorants, colorant suitability should be carefully tested when selecting a colorant. In addition, the kinds of usable colorants have been limited accordingly.
Furthermore, there are cases where some kinds of colorants are unable to give inks having satisfactory storage stability even when formulations are changed. Another drawback of conventional emulsion inks is that according to the degree of kneading of the emulsion ink during continuous printing, the amount of colorant components which dissolve into the aqueous phase or oil phase changes or the interaction between the colorant and components of the oil phase of the emulsion ink changes, and this results in fluctuations in the viscosity of the emulsion ink.

Finely particulate polymer for stencil ink


A DMFC (direct methanol fuel cell) includes two bipolar plates, a membrane electrode assembly, a bonding layer, and a fuel container base. The bipolar plate is a releasable substrate that includes a releasable copper carrier, a release layer, and a metal foil. The bipolar/MEA assembly is formed by laminating the releasable bipolar, the MEA, and the bonding sheet, peeling off the release carrier, and printing a carbon ink or plating Au.

1. Field of the Invention
The present invention relates to a direct methanol fuel cell (DMFC), and more particularly, to a method for fabricating a releasable bipolar of the DMFC.
2. Description of the Prior Art
A fuel cell is an electrochemical cell in which a free energy change resulting from a fuel oxidation reaction is converted into electrical energy. Fuel cells utilizing methanol as fuel are typically called Direct Methanol Fuel Cells (DMFCs), which generate electricity by combining gaseous or aqueous methanol with air. DMFC technology has become widely accepted as a viable fuel cell technology that offers itself to many application fields such as electronic apparatuses, vehicles, military equipment, the aerospace industry, and so on.
DMFCs, like ordinary batteries, provide DC electricity from two electrochemical reactions. These reactions occur at electrodes (or poles) to which reactants are continuously fed. The negative electrode (anode) is maintained by supplying methanol, whereas the positive electrode (cathode) is maintained by the supply of air. When providing current, methanol is electrochemically oxidized at the anode electrocatalyst to produce electrons, which travel through the external circuit to the cathode electrocatalyst where they are consumed together with oxygen in a reduction reaction. The circuit is maintained within the cell by the conduction of protons in the electrolyte. One molecule of methanol (CH3OH) and one molecule of water (H2O) together store six atoms of hydrogen. When fed as a mixture into a DMFC, they react to generate one molecule of CO2, 6 protons (H+), and 6 electrons to generate a flow of electric current. The protons and electrons generated by methanol and water react with oxygen to generate water.
FIG. 1 and FIG. 2 illustrate a conventional DMFC 10, wherein FIG. 1 is a plain view of a conventional DMFC 10 and FIG. 2 is a cross-sectional view of the conventional DMFC 10 along line I-I of FIG. 1. As shown in FIG. 1 and FIG. 2, the conventional DMFC 10 comprises a bipolar plate assembly 12 and a fuel container 14. The bipolar plate assembly 12 comprises an upper frame 51, lower frame 52, a cathode wire lath 121, a plurality of bended bipolar wire laths 122, 123, 124, 125, an anode wire lath 126, and membrane electrode assemblies (MEAs) 131, 132, 133, 134, 135 interposed between corresponding wire laths.
However, the above-described conventional DMFC 10 has several drawbacks. First, the bipolar plate assembly 12 is too thick and thus too unwieldy to carry. Furthermore, as mentioned, the cost of producing the conventional DMFC 10 is high since the cathode wire lath 121, bended bipolar wire laths 122, 123, 124, 125, and the anode wire lath 126 are titanium meshes treated by gold plating. In addition, the throughput of the conventional DMFC 10 is low because the bipolar wire laths 122, 123, 124, 125 are bended manually before mounting on the upper and lower frames. In light of the above, there is a need to provide a thin, inexpensive, and highly integrated DMFC that is capable of achieving the scale of mass production.

Method for manufacturing bipolar plate and direct methanol fuel cell

Nan Ya Printed Circuit Board Corporation


A system and method for descriptively naming links to facilitate subsequent identification of the links. Various naming sources are identified as candidates for inclusion in a link name for the link. Naming rules are applied to identify one or more of the naming sources to be included in the link name. The link name is generated based on the naming sources identified by the naming rules.

In various computing environments, "links" are used to provide shortcuts to a designated location, whether that location be a stored file, network or Internet address, e-mail address, or the like. For example, in the Internet context, Internet "favorites" or other bookmarks provide shortcuts to corresponding Internet sites. The name assigned to the bookmark is generally the only indication of the contents of the bookmarked page. Thus, descriptive naming is essential for productive use of these and other links.
In other computing environments, proper naming is equally important. For example, search engines provide results to queries entered by a user. The naming of the results of such queries is important to allow the user to select the most appropriate search result(s) for the query. This is particularly important where the user interface is associated with mobile devices, where display areas are more limited than their desktop counterparts.
Another representative computing environment where proper naming is important is in the context of recommendations. A recommendation engine can gather information for a particular user or group of users, such as gathering information related to the most likely selection category for that user(s). Based on the information gathered, the recommendation engine can "recommend" sites or content to which there is a higher likelihood of interest to the user. These recommended sites are identified by links, which must include logical and useful names in order for the recommendation to be of use to the user. Such recommendation engines may be used with mobile devices, which as described above, have limited space in which the recommended link name(s) may be displayed.
Currently, such links are generally named by the title of the page that corresponds to the link. Therefore, if the page accessed by the link has a descriptive page title, acceptable naming of bookmarks may be realized. However, the title may be uninformative and in many cases nonexistent. More particularly, one problem with page titles used as bookmark names is that no page title is defined for the page. In such a case, the page title cannot be used at all. Another problem is that the page title may simply be too generic for practical use, and does not adequately specify the content at the link location. For example, a page title may be used as a title on every page of a multi-page web document, and bookmarks to multiple pages would have the same bookmark name. Another problem with page titles as bookmark or other link names is that the title may be ambiguous across different services. For example, a city name may be the page title for weather forecasts, city guides, cinema guides, etc. for that particular city. Therefore, use of the page title may not always be a good means for naming bookmarks, recommendations, search results, or other links.
In other cases, the Uniform Resource Locator (URL) or other Uniform Resource Identifier may be used as the bookmark name. However, URLs are often not representative of the associated content. In some cases, the URLs may be exceptionally long, cryptic, or simply non-descriptive and of little to no use as a naming mechanism.
Accordingly, there is a need for a system and method for providing descriptive names for such links. The present invention fulfills these and other needs, and offers other advantages over the prior art.

System and method for generating descriptive link names


A magnetic device with a three-dimensional wave structure is provided, which contains magnetic elements and a signal receiver. The magnetic element is nano/micron structure with magnetic anisotropy. The magnetic element is formed on a substrate with three-dimensional wave structure. When a magnetic substance approaches to the magnetic element, the magnetic substance produces a corresponding magnetoresistance signal for the magnetic element. Through the measurement of the magnetoresistance of the three-dimensional wave structure, and the presence or absence of the magnetic substance can be detected. An external magnetic field is used to change the magnetization configuration of the three-dimensional wave structure to capture the magnetic substance by adsorbing the magnetic substance to a magnetic pole of the three-dimensional wave structure.

1. Field of the Invention
This application relates to a magnetic device with a three-dimensional wave structure which is applied to detect the variations of the magnetic fields of the magnetic substances by measuring the variations of the magnetoresistance of the three-dimensional wave structure. In addition, the magnetization configuration can be changed by an external magnetic field so as to capture the magnetic substances adsorbed to the magnetic pole region of the three-dimensional wave structure. The present device aims to detect, capture, separate, collect, position, and count the magnetically-tagged biomolecules and the application for the biomedical detection.
2. Description of the Related Art
Recently, with the increasing emphasis on the biotechnology and the growth market of the global biomedical industry depending on the diagnostic medicine and physiology, home physiological monitoring, action health care and implantable medical systems and so on, the productivity and needs of the biotechnology increases gradually. Focus of the technology-related biomedical science wants nothing more than tasks of the biomedical materials, such as detection, capture, analysis and so on. The development of the biomedical detection is the most important. However, most of the conventional biomedical detection systems are applied the optical detection method to detect the cells or the biomolecules tagged by fluorescent substance or quantum dots. The detected solutions for the optical detection method, however, must be transparent and non-turbid and have as few impurities as possible, such that the misjudgment possibility of equipment, which may result from that the light signal from the to-be-detected substance is blocked by the impurities, can be reduced. Furthermore, the commonly used quantum dots may be slightly toxic, and are not suitable for the medical testing of cells.
After the surface of the magnetic nano-particles is modified, the biological toxicity still exists but is within a tolerable range. Hence, the modified magnetic nano-particles are usually applied in the field of biomedical science to process magnetic tagging. Furthermore, the cells or the biomolecules which are magnetically-tagged may indirectly achieve the objective of detecting the cells or the biomolecules through measuring the magnetic field emitted by the magnetic nano-particles. Similarly, the purification and collection of the biomolecules can be implemented through manipulating an external magnetic field.
Currently, most of the sensors applied to detect the magnetic substances are the element with two dimensional flat surfaces, and the applied range is therefore limited. Although the conventional technique has disclosed that a plurality of flat surface elements are assembled to form a three-dimensional magnetic detector, manufacturing process and the determining process of the necessary detection elements are more complicated.
In conclusion, the inventor of the present invention has been mulling the aforementioned technical problems over, and then designs a magnetic device with a three-dimensional wave structure and an application for the biomedical detection which is applied to overcome the existing drawbacks so as to promote the industrial applicability.

Magnetic device with three-dimensional wave structure and application for biomedical detection


A coil of superconducting wire for a superconducting magnet having a relaely dense and uniformly spaced winding to enhance the homogeneity and strength of the magnetic field surrounding the coil and a method of winding the same wherein the mandrel used to wind said coil comprises removable spacers and retainers forming a plurality of outwardly opening slots, each of said slots extending generally about the periphery of the mandrel and being sized to receive and outwardly align and retain successive turns of the superconducting wire within each slot as the wire is wound around and laterally across the mandrel to form a plurality of wire ribbons of a predetermined thickness laterally across the mandrel.

The present invention relates to a method of winding a coil of superconducting wire for a superconducting magnet, and, more particularly, to a winding arrangement wherein the windings of the coil are uniform and dense, such that the resulting superconducting magnet produces a strong and homogeneous magnetic field and yet is physically compact and energy efficient.
Superconducting magnets and the methods of their manufacture are well known in the art. At cryogenic temperatures, superconducting wire loses virtually all ohmic resistance and allows the free flow of electricity for long periods of time and in very high current densities. Because the current density in a superconducting coil can be hundreds of times higher than in nonsuperconducting coils, very strong magnetic fields can be obtained, and, as a result, superconducting magnets have found extensive application in devices such as high energy particle accelerators, plasma confining tokamaks, synchrotron radiation sources, nuclear magnetic resonance imaging systems, and magnetic levitation devices. However, due to continuous demands for greater power and accuracy of these devices, there is a continual need for a more efficient superconducting magnet which can provide stronger and more homogeneous magnetic fields and at the same time is physically more compact and requires less power.
A prime example of the application of more efficient superconducting magnets is in the construction of the Superconducting Super Collider (SSC) particle accelerator which will use thousands of superconducting magnets to bend and focus high energy particle beams in a generally circular orbit. Although the main superconducting magnetic coils of the SSC are designed to exhibit minimal magnetic field harmonics, due to superconductor magnetization effects, iron saturation and coil positioning errors, certain harmonic errors are possible which must be corrected with multipole corrector or adjustment coils. Additionally, multipole corrector coils are utilized to focus the particle beam into a desired stream, so as the energy of the particles increases, the strength of the corrector coils must likewise be increased. Therefore, there is a need for corrector coils which can provide strong and homogeneous magnetic field and, yet, are compact and energy efficient.
Although the use of corrector coils to correct magnetic field deviations and to focus the particle beam is well known, the production and use of these coils are complicated by a number of factors. First of all, the superconducting wires utilized in the windings are typically of very small diameter and are generally more brittle than normal conductors, so therefore greater care must be exercised in the winding and forming of such superconducting magnets. Another factor is that the coils are very lengthy (more than a meter in length) while the spacing between the adjacent turns of the coil must be precisely maintained, so it is difficult and time consuming to wind uniform layers of wire which are physically stable so as to prevent generation of frictional heat from coil movement resulting from the electromotive forces of the large currents. Additionally, the coils must be physically compact so that it may easily be cooled to cryogenic temperatures.
Until now, such correction coils have been randomly wound around a mandrel to obtain the coils of desired length and then shaped into desired configurations to fit around the bore tube. However, because the windings of these previous coils were not essentially uniform, the magnetic fields they generated were neither as homogeneous or as strong as desired.
As can be seen from the foregoing, one of the requirements for an efficient superconducting magnet is that it have a uniform, homogeneous cross-section with a high density of superconducting wire within its cross-sectional area. As the windings are made more uniform and with greater cross-sectional density, the magnetic field produced by the windings is stronger and more homogeneous. This also means that the resulting superconducting magnet requires less energy and, yet, is physically more compact. These advantages would also facilitate greater flexibility in the positioning of these corrector coils about the bore tube and make it easier to cryogenically cool the same.
In nuclear magnetic resonance (NMR) imaging, homogeneous magnetic fields are required to obtain optimum image data. Although the main magnetic coil of a NMR imaging system is designed to produce a homogeneous a magnetic field as is possible, some spatial deformity is inevitable, and it is standard practice to utilize corrector coils to perturb the magnetic flux pattern to increase the overall homogeneity of the magnetic field. However, the process of measuring the magnetic field deformity and calculating the positioning and magnitude of the corrector coil current is a tedious and time consuming process. Therefore, a corrector coil that produces a more homogeneous magnetic field would simplify and speed-up the correcting process.
Likewise, in constructing synchrotron radiation and magnetic levitation devices, it is essential to have compact and efficient superconducting magnets which can produce strong yet homogeneous magnetic fields.
In view of the foregoing, the general object of this invention is to provide a method of winding a coil of superconducting wire for a superconducting magnet having a relatively dense and uniformly spaced windings to enhance the homogeneity and strength of the magnetic field produced by the superconducting magnet.
Another object of this invention to provide a mandrel for winding a coil of superconducting wire for a superconducting magnet having a relatively dense and uniformly spaced windings.
Yet another object of this invention is to provide a coil of superconducting wire having relatively dense and uniformly spaced windings.
Additional objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following and by practice of the invention.

Uniformly wound superconducting coil and method of making same

The United States of America as represented by the Department of Energy


A data storage system includes an encoder subsystem comprising an error correction code encoder, a modulation encoder, and a precoder, and a decoder subsystem similarly comprising a detector, an inverse precoder, a channel decoder, and an error correction code decoder. The error correction encoder applies an error correction code to the incoming user bit stream, and the modulation encoder applies so-called modulation or constrained coding to the error correction coded bit stream. The precoder applies so-called precoding to the modulation encoded bit stream. However, this precoding is applied to selected portions of the bit stream only. There can also be a permutation step where the bit sequence is permuted after the modulation encoder before precoding is applied by the precoder. The decoder subsystem operates in the inverse manner.

As is known in the art, when storing data in a data storage system it is common to "code" the "raw", original user data in some way so as to, for example, make the data storage more efficient, and less susceptible to errors. There are typically three types of coding that are employed when storing data on a storage medium.
Firstly, the original data would normally be compressed in some way. This is commonly referred to as source coding. The next stage is usually to encode the compressed data to provide some form of error protection. This usually involves a coding process that adds a few bytes to the data, which bytes can then be used to detect and correct errors when the data is read out. A common example of such error correction coding (ECC) is Reed-Solomon coding.
The error correction coded data is then typically subject to further encoding, which further encoding is usually referred to as "modulation coding." This coding is used to impose constraints on the data sequences written on to the storage medium (e.g., such that there can be no more than three consecutive "0"s) and is done for "house-keeping" purposes, e.g., to aid timing recovery and gain control and to shorten the detector path memory. Modulation coding can also improve performance of the storage system (an example of this is the use of (d, k) codes in magnetic and optical storage systems).
After modulation coding, the data may then be further "parity" coded, as is known in the art, to add one or more parity bits to the data. Thereafter the data can be written to the storage medium, e.g. magnetic tape or disk drive, or optical disk, and stored.
Reading the data from the storage medium and restoring the original data is the reverse process. Thus, for example, the detector output read from the storage medium is fed to a post-processor that performs soft-decision decoding of the parity-check code, a modulation decoder is then used to invert the modulation coding, and finally an error detection decoder is used to correct errors and deliver (its estimate of) the (compressed) original user data.
As is known in the art, the modulation coding step discussed above usually involves two steps. The first is so-called modulation coding that maps bits in the input data stream to a particular constrained output bit arrangement; for example a 16/17 code mapping a 16 bit input to a constrained 17 bit output data sequence. Examples of such modulation coding are constrained codes such as so-called run length limited (d, k) constrained codes, (G, I) constrained codes, and maximum transition run (j, k) constrained codes. Hereinafter, the term "modulation coding" will be used to refer to the application of this form of constrained coding, excluding any subsequent precoding step (see below).
The second step in the overall "modulation" coding process is so-called "precoding". Precoding operates on the "constrained" coded data and operates, as is known in the art, effectively to convert or translate a more simple set of constraints that are imposed on a data sequence by modulation (constrained) coding into a larger and more complex set of constraints that it is actually desired to impose on the data sequence, e.g., at the channel input. For example, with reference to the above discussed coding "constraint" of there being no more than three "0"s in succession, the use of precoding can "translate" that relatively simple constraint into the twin requirements that there can be no more than four "0"s in succession and that there can be no more than four "1"s in succession. For a given encoder and decoder structure, such as a block encoder and block decoder, precoding may allow stronger constraints to be imposed on the data sequence but without the need for a commensurate increase in the complexity of the modulation coding that is applied. Thus using precoding simplifies the modulation coding that needs to be performed. Examples of precoding techniques that are used are so-called 1/(1⊕D2) and 1/(1⊕D) precoding, as is known in the art (where ⊕ indicates the Boolean logic operation XOR (exclusive OR)).
As is known in the art, the overall aim of modulation coding and precoding is to adapt the data signal to the (recording) channel that it is subsequently to be "transmitted" on. A more general discussion of coding, including modulation coding and precoding, can be found, e.g., in K. A. S. Immink, P. H. Siegel, and J. K. Wolf, "Codes for Digital Recorders", IEEE Trans. Inform. Theory, Vol. 44, pp 2260-2299, October 1998.
However, a disadvantage to the use of precoding is that it can introduce error propagation and increase errors when the stored data is read out. This is because, as is known in the art, in the inverse precoding step each single read stored bit is usually used to determine two output bits of the inverse precoding process. Thus an error in a single stored bit can result in two bit errors in the output from the inverse precoder. This can then lead to further error propagation in modulation decoding and degrade error correction performance.

International Business Machines Corporation