This invention relates to a hydrocarbon conversion process using a novel beidellite layered clay as the catalyst. The clay is characterized in that it is substantially free of sodium cations, is composed of crystals whose average crystallites size is about 50-150 Angstroms, has a surface area of at least 80 m.sup.2 /g and has its 060 X-ray diffraction peak at a d-spacing of 1.50 Angstroms. The clay is prepared from a reaction mixture containing reactive sources of aluminum and silicon, a templating agent and water. The mixture is reacted at a pH of about 8.5 to about 14, a temperature of about 150.degree. to about 210.degree. C. for a time of about 1 to about 20 days. The clay may be used as is or after pillaring the layers with pillars such as alumina, ZrO.sub.2, TiO.sub.2, etc. The hydrocarbon processes which can be catalyzed by this clay are cracking, hydrocracking and alkylation of both aromatic and paraffinic hydrocarbons.

Naturally occurring clays such as dioctahedral smectites are composed of semicrystalline aluminosilicate layers (lamellae) held together by Van der Waals and electrostatic forces. Anionic charges on the siliceous layers are neutralized by cations in the interlamellar spaces. These cations are usually sodium, calcium, or potassium. When these cations are large oligomers of inorganic cations such as Fe.sup.+3, Cr.sup.+3 or when they are metal hydroxy polymer cations such as (Al.sub.13 O.sub.4 (OH).sub.24 (H.sub.2 O).sub.12).sup.7+ or (Zr(OH).sub.2.4H.sub.2 O).sub.4.sup.8+, they act as pillars, propping the clay layers apart to afford a pillared layered clay. Upon heating, these oligomers or polymers are converted to the metal oxide, thus preventing the collapse of the clay layers and thus pillaring the clay.
These smectite clays are known to catalyze reactions such as alkylation, cracking, ester formation, dimerization, oligomerization, etc. However, because the naturally occurring clays have a large variation in impurity content, industrial demand for the natural smectites has been very limited. Therefore, attempts have been made to synthesize some of these smectite clays. For example, European Patent Application 163560 discloses a method of preparing a beidellite clay (one of the smectite clays). The process involves taking a mixture containing aluminum nitrate, tetraethylorthosilicate (TEOS), sodium carbonate and sodium hydroxide, drying the mixture and then calcining to give aluminum oxide, silicon oxide, and sodium oxide, adding to that hydroxide anions and heating the resultant slurry to a temperature of about 340.degree. C. for 14 days. Although this method produces a beidellite that is purer than the naturally occurring beidellite, the use of oxides leads to incomplete reaction even though the synthesis is carried out at high temperatures. Additionally, the presence of sodium is detrimental to the catalysis of certain reactions and therefore, the sodium has to be replaced by some other cation.
Applicant has solved the problems with the synthesis of beidellite found in the prior art by using a reaction mixture which contains a secondary or tertiary amine, a quaternary ammonium salt or a quaternary phosphonium salt along with reactive sources of aluminum and silicon. For example, tetramethylammonium hydroxide is mixed with alumina and colloidal silica along with water at a pH of about 8.5 to about 14 and reacted at a temperature of 150.degree.-210.degree. C. for about 1 to 20 days to provide a TMA.sup.+ -beidellite. The resultant product is also unique in that unlike the beidellites which are described in the prior art, the instant product has crystals whose average crystallite size is about 50-150 Angstroms, has a surface area of at least 80 m.sup.2 /g, is substantially free of sodium cations and has its 060 X-ray diffraction peak at a d-spacing of 1.50 Angstroms. The tetramethylammonium cations have taken the place of sodium cations that are present in prior art beidellite products. Although the prior art shows that a sodium beidellite can be exchanged with an alkyl ammonium compound the resultant exchange product does not have the same characteristics as the instant composition.
Although the prior art shows that quaternary ammonium compounds can be used to prepare some synthetic clays, there is no indication that an amine, a quaternary ammonium compound or a quaternary phosphonium compound could be used to prepare a synthetic beidellite. For example, R. M. Barrer and L. W. R. Dicks in J. Chem. Soc. (A), 1967, 1523-1529, have shown that alkyl ammonium compounds can be used to synthesize montmorillonites and hectorites. Thus, applicant is the first to synthesize an alkyl ammonium beidellite having small crystallites, a large surface area and its 060 peak at a d-spacing of 1.50 Angstroms.

Hydrocarbon conversion process using a novel beidellite clay


The invention described herein generally pertains to a system and method for a voltage sense lead being disposed on or within a welder gun in a hot wire application (e.g., hot wire laser, hot wire hybrid, and the like) to monitor voltage across the electrode. In this manner, resistive heating can be regulated to ensure that the wire and weld pool (e.g., puddle) temperature are within a desired range. The voltage sense lead can be incorporated into a welder gun or onto a welder gun in order to mitigate inaccuracies and voltage drops resultant of a cable connecting the welder gun to the wire feeder of a hot wire system.

Welding systems reside at the core of the modern industrial age. From massive automobile assembly operations to automated manufacturing environments, these systems facilitate joining in ever more complicated manufacturing operations. Hot wire welding processes a wire or electrode being heated (e.g., via current) and received by a puddle created by a main heat source (e.g., plasma arc, tungsten inert gas (TIG) welding, metal inert gas (MIG) welding, flux core, laser, among others). The hot wire welding process includes the resistance heating of the up to or near a melting point of such wire. In hot wire welding processes, the formation of an arc is avoided since an arc condition disrupts or overheats the puddle. Yet, a wire heated near or close to the melting point of the wire without arcing events is received by the puddle with little or no disruption. In order to prevent a formation of an arc, a welding parameter related to the workpiece can be detected. The welding parameter can indicate an arc condition in which the hot wire welding process can be adjusted. For instance, voltage is a welding parameter that is normally detected from a conductor block within a wire feeder taken with respect to some point within the work lead or workpiece. Measurement of the welding parameter at the conductor block may include inaccuracies and false readings due to voltage drops across the welder gun and the cable connecting the welder gun to the wire feeder and/or conductor block. This cable and welder gun generate a voltage drop (e.g., up to 1.5 volts in extreme conditions) and other inaccuracies which affect the hot wire welding process in light of having a low voltage operation range (e.g., 7 volts to 8 volts).
As mentioned, a hot wire welding process can be compromised by a voltage drop caused by a cable connection and what is needed is an improved technique to detect voltage in a hot wire welding environment.


Footwear with interchangeable components on the ankle area and tongue is herein disclosed, wherein both the replacement tongue and the upper area of the footwear comprise different materials, colors, or styles. The removal and replacement functionality is accomplished with a plurality of snap fasteners. To remove the upper portion of the footwear, the laces would be removed from the eyelets, an upper portion and tongue interchanged, and the laces replaced. It is also envisioned that the upper portion and tongue could be removed completely and shorter laces installed to transform the footwear into a pair of shoes as well.

Modern fashion trends dictate an ever evolving and changing of popularity wherein the clothing, shoes, and fashion accessories that are considered cutting edge today are considered passé tomorrow. In keeping with these trends, society has a strong desire to be different and is willing to be judged by the fashions that one wears. Thus, the fashion industry is in a constant search for new and innovative styles and solutions that will help to define the next fashion trend. Not limited strictly to clothing, this need for innovation extends to all areas of fashion, including that of accessories, such as shoes and boots. Accordingly, there is a constant need for new and innovative ideas that not only create new fashion styles, but also that invigorate the fashion industry. The development of the footwear herein described fulfills this need.
Footwear exists in many different discrete forms ranging from open toed sandals to full length boots. Many people expend great amounts of money on their choice of footwear. Many find it difficult to maintain a fashion "edge" while being economical. An article of footwear that comprises a detachable upper assembly would provide an economical means while remaining fashion conscious.
There have been attempts in the past to invent boots that convert into shoes. U.S. Pat. No. 6,851,203 issued to Roelofs discloses footwear with attachable clothing that may be useful in the event of biological, chemical or radiation attacks. Unfortunately, this patent does not appear to disclose footwear with interchangeable decorative features such as a detachable upper assembly and detachable upper tongue that may coordinate to suit a user's fashion sense.
U.S. Pat. No. D 344,169 issued to Brown appears to disclose a convertible tennis shoe. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed device, nor does it appear to teach a detachable upper assembly and detachable tongue that use fasteners to attach to a lower boot assembly.
U.S. Pat. No. D 333,204 issued to Terrell discloses a sneaker with a cowl like upper. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed device, nor does it appear to teach footwear with interchangeable decorative features such as a detachable upper assembly that may be changed to reflect a user's personal fashion taste.
U.S. Pat. No. D 280,567 issued to Ji discloses what appears to be a sneaker with a zippered detachable upper. Unfortunately, this design patent does not appear to be similar in appearance to the disclosed device, nor does it appear to comprise an upper section with a plurality of eyelets and a detachable upper tongue section.
U.S. Pat. No. 4,693,018 issued to DuPree discloses a detachable upper for a sneaker comprising a hook and loop fastener. Unfortunately, this patent does not disclose footwear with multiple interchangeable decorative features such as upper assemblies and tongues that may be added to reflect one's fashion sense, nor does it appear to disclose an upper that comprises eyelets and other features to discretely disguise the addition of the upper assembly to an article of footwear.
U.S. Pat. No. 4,958,447 issued to Maleyko et al. discloses an athletic shoe with break-away high top that appears to attach to a shoe through hook-and-loop fasteners. Unfortunately, this patent does not disclose footwear with multiple interchangeable decorative features such as upper assemblies and tongues that may be added to reflect one's fashion sense, nor does it appear to disclose an upper that comprises eyelets and other features to discretely disguise the addition of the upper assembly to an article of footwear.
U.S. Pat. No. 4,064,641 issued to Levine discloses an article of footwear with a cuff like section on the upper part of the footwear. Unfortunately, this patent does not appear to disclose an article of footwear with a detachable, interchangeable upper assembly and upper tongue.
U.S. Pat. No. 3,983,642 issued to Liao discloses a shoe having interchangeable uppers. Unfortunately, this patent does not appear to disclose footwear with interchangeable decorative features such as a detachable upper assembly and detachable upper tongue that may coordinate to suit a user's fashion sense.
U.S. Pat. No. 3,744,158 issued to Walker discloses a sportsmen's boot with a detachable extension. Unfortunately, this patent does not disclose footwear with multiple interchangeable decorative features such as upper assemblies and tongues that may be added to reflect one's fashion sense, nor does it appear to disclose an upper that comprises eyelets and other features to discretely disguise the addition of the upper assembly to an article of footwear.
U.S. Pat. No. 2,607,133 issued to Marlowe discloses a shoe with detachable upper. Unfortunately, this patent does not appear to disclose footwear with interchangeable decorative features such as a detachable upper assembly and detachable upper tongue that may coordinate to suit a user's fashion sense.
U.S. Pat. No. 854,274 issued to Crook et al. discloses an attachment for shoes that appears to comprise an upper that utilizes snap fasteners to attach to a shoe. Unfortunately, this patent does not disclose footwear with multiple interchangeable decorative features such as upper assemblies and tongues that may be added to reflect one's fashion sense, nor does it appear to disclose an upper that comprises eyelets and other features to discretely disguise the addition of the upper assembly to an article of footwear.
None of the prior art particularly describes a footwear with removably attachable components on the ankle area and tongue that the instant device possesses. Accordingly, there exists a need for a line of boots that operates without the disadvantages as described above.

Footwear with interchangeable decorative features


The sighting system has a sight including an aiming mirror (16) which is steered about a circular axis that is fixed relative to a support secured to a carrier, and about an elevation axis (18) under the control of motors (15, 22) to bring the direction of light which is received along a reference sighting line in a geographical frame of reference (x, y, z) to the direction of the circular axis, and measurement device for measuring the real angles imparted to the aiming mirror (16) about circular and lateral axes by the motors. A gyro unit continuously delivers angles for converting the reference frame of reference (x, y, z) to a frame of reference tied to the support (x1, y1, z1). A computer and servo-control unit controls the motors (15, 22) on the basis of information received from the gyro unit (60) and from the measurement device. This unit is designed to compute and transmit to a user device the real position of the sighting line on the basis of information supplied by the measurement device and on the basis of stored parameters modelling at least the optical and mechanical defects of the sight.

The present invention relates to a stabilized optical sighting system for mounting on a carrier vehicle which, as it moves, is subjected to disturbing roll, pitch, and yaw movements. A particularly important application is on board ships where such disturbances are practically continuous and can be of large amplitude. Nevertheless, the invention is applicable to any medium subjected to such movements, in particular for making sighting systems that enable panoramic surveillance to be performed, i.e. the line of sight should be maintained at an angle of elevation that is constant relative to the horizon while simultaneously causing the line of sight to rotate about an axis that is vertical. The term "optical" should be understood broadly as covering both infrared sighting and sighting in the visible range.
Stabilized optical sighting systems are known that comprise a sensor mounted on a platform that is kept fixed relative to a geographical frame of reference by mounting the system on gimbals provided with motors controlled on the basis of information provided by a navigation control center. The sensor and the platform supporting it together have a large amount of inertia; that degrades the dynamic behavior of the system and requires motors of considerable power.
Consequently, the invention relates to a stabilized sighting system of a type that reduces the inertia of the moving parts comprising an aiming mirror whose orientation about an elevation axis and about a "circular" axis that is fixed relative to a platform secured to the carrier, is controlled to bring the direction of light received along a sighting line that is determined in a geographical frame of reference to a direction that is constant relative to the support, said constant direction being that of the circular axis in the frequent case of a panoramic system.
Often the aiming or sighting mirror is also steerable about a "lateral" axis which is parallel to the circular axis at zero elevation. This structure makes it possible, in particular, to provide a panoramic sight whose mirror is driven at constant speed about the circular axis, with any disturbing movements that tend to alter the angle of elevation being compensated by controlling both a motor for rotating the mirror about the elevation axis and a motor for rotating it about the lateral axis.
FIG. 1 is a diagram showing the theoretical structure of such a system having a lateral axis, together with the parameters involved in controlling it, and the notation that is used below, this figure not being to scale.
The system comprises a sight proper placed at the top of a mast 10 fixed to the deck of the ship 12. It has a head 14 which is steerable by a motor 15 about a circular axis z.sub.1 perpendicular to the deck and relative to a platform 32 which is fixed to the mast. In FIG. 1, x.sub.1 designates the longitudinal axis of the ship (lubber's line), and y.sub.1 the axis lying in the plane of the deck and extending orthogonally to x.sub.1 and z.sub.1. In the head 14, an aiming member constituted by an aiming mirror 16 is steerable both about an elevation axis 18 perpendicular to the circular axis, and about a lateral axis 20 perpendicular to the elevation axis 18. Rotation about the elevation axis 18 is controlled by an elevation motor 22. The output shaft of this motor carries a support 24 both for the lateral axis 20 and for the lateral motor 26 which controls rotation of the aiming mirror about the lateral axis. A deflecting optical assembly 28 deflects the light path so that light leaves the sight substantially along the circular axis. The deflection is generally through 90.degree.. The beam of light coming from the direction of the sighting line 30 is thus successively reflected by the aiming mirror 16 and deflected by the assembly 28.
The sighting line 30 can be defined by a true! elevation angle Si and by an azimuth angle Az in a geographical frame of reference xyz.
The laws for controlling rotation about the circular, elevation, and lateral axes are much more complex than the laws for controlling a platform to keep it fixed relative to a geographical frame of reference, in particular because the lateral axis is moved by the elevation axis. The rate of rotation to be imparted about the circular axis z.sub.1 relative to the ship differs from the azimuth rate to be imparted relative to the terrestrial frame of reference xyz because of the roll, pitching, and yaw movements of the ship. In order to perform panoramic scanning at constant elevation and at substantially constant azimuth rate, the steering angles about the circular, elevation, and lateral axes must all vary continuously. Computing them in real time by successive approximation methods requires very high computation power, given the inevitable defects of the system.


The present invention relates to systems and methods for providing a personalized exchange market, and more specifically, to systems and methods for establishing personalized pledge agreements for uncertain future events or occurrences. In one embodiment, the invention includes a method including the steps of facilitating a pledge offer via a network, the pledge offer specifying an outcome of an uncertain future occurrence, the uncertain future occurrence being independently definable; facilitating an acceptance of the pledge offer over via the network, the acceptance forming a pledge agreement; determining the outcome; and facilitating performance of the pledge agreement based on the outcome.

The future is inherently uncertain. This uncertainty encompasses uncertain future events or occurrences at both the macro- and micro-levels. Uncertain future events or occurrences may include anything in the future, including outcomes, measurements, processes, developments, discoveries and, of course, events or occurrences. Further, the uncertainty is indiscriminate to the time frame for which it operates, for both near and future events or occurrences may have a degree of unpredictability. For instance, it is uncertain whether inflation will rise, fall, or stay the same in the coming months. It is also uncertain whether, and to what degree, the price of a family home will increase, decrease, or stay the same over a given time period. And, it is uncertain whether a single child will marry before a certain age or remain a dependent until a certain age. Indeed, the uncertainty encompasses all perspective levels, from broad to narrow, for all future time periods, for all tangible and intangible subject matter. For many, this uncertainty brings excitement; however, the uncertainty also presents the risk that certain events or occurrences do not occur as anticipated, leading in some instances to financial losses or disappointment. In these instances, it would be desirable to predict, manage, guarantee, assure, or speculate in risks for future uncertain events or occurrences.
First, predicting uncertain future events or occurrences would be desirable for planning and making more informed or less risky decisions. For instance, if inflation is predicted to rise, it may be prudent to prepare for interest rate increases by minimizing mortgage payments or paying off debt. Also, if the real estate prices in a particular neighborhood are predicted to increase, it may be desirable to make real estate purchases before this anticipated increase. Further, if a child is predicted to marry, it may be wise to plan for wedding expenses or even the possibility of his/her being "jilted" and losing a banquet hall or reception deposit. Certainly, few would argue that accurate predictions of uncertain future events or occurrences are not valuable. Yet, achieving accurate predictions has been elusive in surveys, questionnaires, censuses, evaluations, assessments, or any other forecasts. Predictions often have error margins due to lack of motivation, lack of a tangible incentive, or inherent prejudice in the phrasing of questions. Further, pollees are sometimes not capable of giving informed opinions, completely answering the poll, satisfying the poller, thereby diminishing the accuracy of the poll itself. Similarly, expert opinions are limited in that they constitute, at most, only a few viewpoints, are sometimes obsolete, are founded on past rather than future performance, and are not easily verifiable. Thus, more accurate predictions of uncertain future events or occurrences would be desirable.
Next, managing the risks in uncertain future events or occurrences would be desirable for hedging against incorrect predictions, biases, or assumptions about the future. For instance, as discussed above, it would be beneficial to hedge against the risk of incorrectly converting variable rate loans to fixed rate loans under an assumption that interest rates were going to rise rather than fall. Similarly, as discussed above, it would be desirable to hedge against the risk of incorrectly purchasing a house in a particular neighborhood under the assumption that housing prices in that particular neighborhood would increase. Further, it would be beneficial to hedge against the risk of incorrectly investing in a particular ingredient for a drug under the assumption that the drug would ultimately gain FDA approval or achieve market success. Various institutions have pre-determined areas for risk management and have marketed and/or packaged these pre-determined products. However, pre-determined approaches do not provide risk management abilities for independently determinable uncertain future events or occurrences. For instance, there is no independently determinable risk-management system for whether a particular patent will be valuable, whether it will issue within a given time frame, or whether particular claims within the patent will be allowed by an examiner. Similarly, there is no independently determinable risk-management system for whether tomorrow will bring sunshine for a wedding or whether a particular product within a company will meet or surpass revenue forecasts. Further, there is no independently determinable risk-management system for whether a medical school graduate will be "matched" with a particular residency training program or remain jobless and still be responsible for medical school tuition debt. Without an independently determinable risk-management system an entity is unable to address particularly and precisely risks in uncertain future events or occurrences that are not pre-determined. Accordingly, an independently determinable risk-management system for any uncertain future event or occurrence would be desirable.
Also, as a complement to managing the risks of inherently uncertain future events or occurrences, it would be desirable to have an organized system for risk-bearing, speculative, profit-oriented, or otherwise motivated third parties to assume certain particular and precise risks in uncertain future events or occurrences from anyone, anywhere, for anything. For instance, it would be beneficial to provide an ability for one individual or entity to assume the risk of any independently determinable uncertain future event or occurrence, such as inflation changes, real estate market price changes, a marital status change, or adverse weather for a particular day and a precise location from another particular individual, small business, or other entity located anywhere in the world. Risk transfer systems to date are pre-determined, whereby a centralized person or organization pre-determines and/or packages the risks that may be transferred, which indirectly mandates the risk burden for all non-addressed uncertain future events or occurrences. Thus, it would be desirable to facilitate the transfer of any independently determinable uncertain future event or occurrence risk among any number of persons, anywhere, for anything.
What is needed then are systems and methods for providing a personalized exchange market, and more specifically, to systems and methods for establishing personalized pledge agreements for uncertain future events or occurrences.

Systems and methods for providing a personalized exchange market


A method for implementing an activity based resource assignment medium access control (MAC) protocol to allocate resources to subscribers in an interactive, multimedia, broadband satellite communications system. A plurality of channels is provided with at least one of said plurality of channels being assigned to each of a plurality of terminals. Utilization of the channel resources by the plurality of terminals is monitored and an evaluation is conducted of system needs based on the levels of activity and utilization of channel resources by the terminals. Requests for system resources by the terminals are communicated to a resource controller which calculates the system needs. The resource controller is utilized to adjust the channel resources based on the levels of activity and utilization of resources by the terminals. The adjustment provides active terminals as much resources as required during duration of their activity, subject to resource availability.

1. Technical Field
The present invention relates generally to an improved communications system and more specifically to an improved satellite communications system. Still more particularly, the present invention relates to a method and system of assigning communication channel resources of an interactive multimedia satellite communications system to increase throughput efficiency while maintaining low access delays.
2. Description of the Related Art
Factors driving the need for broadband communications arise from changing user needs and demands. The International Telecommunications Union (ITU, formerly known as CCITT) defines broadband service as a service requiring transmission channels capable of supporting rates greater than 1.5 Mbps or a primary rate in ISDN or T1 or DS1 in digital terminology. A broadband integrated services digital network (BISDN) technology framework involves asynchronous transfer mode (ATM) as a protocol for coordinating information between source and destination nodes. Previously, public network needs were driven by telephoning, voice data. Data traffic has grown slowly until recently. With the lower cost in telecommunications and the higher increase in processing power of computers, the numbers of users accessing communications networks has increased. The needs of these users include, for example, video telephone, low cost video conferencing, imaging, high definition television (HDTV), and other applications requiring multimedia data transfers. Multimedia combines different forms of media in the communication of information between a user and a data processing system, such as a personal computer. A multimedia application is an application that uses different forms of communications within a single application. Multimedia applications may, for example, communicate data to a user on a computer via audio, text, and video simultaneously. Such multimedia applications are usually bit intensive, real time, and very demanding on communications networks.
Satellite communication systems are generally known to facilitate communication with user terminals across most areas of the Earth. In a satellite communication system, at least one satellite operates from an orbit above the earth. International telecommunication satellites typically operate from a geostationary orbit (GEO) that is approximately 36,000 kilometers above the surface of the earth.
Satellite communications, in particular GEO orbit satellites communications, are subject to long access delay. Contention access methods which can serve a large number of low duty cycle terminals well in low delay terrestrial radio environment do not perform efficiently in satellite systems.
Traditional very Small Aperture Terminal (VSAT) systems are designed to handle smaller numbers (a hundred or less) of terminals of relatively higher duty cycle. These VSAT systems often utilize a reservation based system, wherein a small amount of bandwidth is dedicated to each terminal for communicating a terminal""s request to the gateway or hub. However, such reservation based system tends to be inefficient when a large number of low duty cycle terminals are sharing a pool of transmission channels.
Two specific examples of current contention access protocols are ALOHA and Reservation based. An ALOHA contention protocol will give very poor delay and throughput performance when utilized for a system with a large, active terminal population. In a system utilizing an ALOHA contention protocol, every terminal at every instant has the right to transit over the channel. There will be collisions, and the colliding packets will be destroyed. When this happens, each terminal waits a random period and then resends its packet. This provides low delay with minimal control overhead when the system is very lightly loaded or has relatively few active terminals. As the loading increases, so does the number of colliding packets, and thus the average delay associated with each packet. Further, the efficiency drops as more of the channel is wasted by colliding packets. The maximum throughput in an ALOHA system is limited to about 36% of the system capacity. As the load offered by the terminals approaches and passes this limit, the system throughput drops and the delay performance deteriorates rapidly.
There are many performance limitations of the circuit switched and burst-by-burst media access control (MAC) protocols. Circuit switched protocols assign fixed bandwidth to each active terminals. This works very well for relatively constant rate terminals where the channel size can be matched to the terminal transmission needs. However, for large populations of bursty multimedia users, circuits sized to the average terminal transmission need will give very poor delay performance, and circuits sized to give good delay performance to handle the terminal bursts will result in very poor system utilization.
Considering circuit switched performance for a simple example wherein 100,000 subscribers share 100 time division multiple access (TDMA) channels, and wherein the multimedia traffic offered by the user to the terminal is a block of data equivalent to 1 second of the TDMA channel every 100 seconds. This gives the average offered load of 1%. With 50 simultaneous sessions, the average assignment to each user is at most 2% of the TDMA channel. The delay performance is poor in that a terminal with this assignment would require 50 seconds to transmit each block of data. The channel utilization is 50% in this case. The delay performance could be improved by raising the connection rate. However, a higher connection rate reduces the number of subscribers that each channel would be able to support. The higher connection rate will also result in poorer utilization of the TDMA channel as each connection sits idle between bursts.
Burst-by-burst MAC protocols have the potential to provide better delay and channel utilization performance, but at the cost of significantly higher signaling overhead. In the burst-by-burst protocol, the subscriber makes a request for a specific number of TDMA slots and after receiving an allocation, transmits only in those slots. There is an intrinsic 0.5 second double hop delay in this approach. In addition, it requires significantly greater signaling overhead associated with the resource requests and allocations. Still greater delays may occur if the reservation request channel operates with a contention protocol with-the result that simultaneous requests collide and must be resent. With this MAC approach, it is possible for the signaling overhead to swamp the traffic data. The burst-by-burst MAC protocol would perform very well for traffic with characteristics described above. However for the case where the same quantity of traffic arrives as a constant stream of bursts, the signaling overhead inefficiency becomes apparent.
Assume that the traffic arrives in blocks of data equivalent to 0.01 second of the TDMA channel every second. The terminal needs to make a request and receive a burst assignment for each of these blocks. The request/assignment exchange introduces a delay of at least 0.5 second. Further, there is a delay waiting for the allocated slot time. Also, the high signaling requirement can result in a low overall efficiency.
Interactive multimedia traffic is characterized by intermittent bursts at very high rate surrounded by periods of inactivity and a resulting low average rate. A switched circuit connection approach performs poorly for multimedia traffic. With circuit switching, a terminal must establish and maintain a connection for the duration of its session. If the circuit rate is near the average data rate, the link can have extremely poor delay performance. If it is set near the burst rate, the link will be very inefficient. In the first case, the subscriber is likely to be dissatisfied with the performance. In the latter case, the subscriber is likely to be dissatisfied with his usage charges.
Terrestrial wireless broadband networks have been studied extensively in recent years and many MAC protocols have been put forward. A key difference between terrestrial systems and satellite systems for this application is the difference in access delay. Whereas the MAC protocols for terrestrial systems can rely on the nearly instantaneous responses to user resource requests, the request/response access delay in a geosynchronous satellite system with ground based resource scheduling is one-half second.
It would therefore be desirable to have a MAC protocol tailored for a satellite environment. It would further be advantageous to have such a MAC protocol which can efficiently handle bursty traffic such as multimedia traffic. Further, it would be desirable to have a multimedia MAC protocol which provides high resource efficiency and provides low access delay.
It is therefore one object of the present invention to provide an improved communications system.
It is another object of the present invention to provide an improved satellite communications system.
It is yet another object of the present invention to provide a method and system of assigning communication channel resources of an interactive multimedia satellite communication system to increase throughput efficiency while maintaining low access delays.
The foregoing objects are achieved as is now described. A method is disclosed for implementing an activity based resource assignment medium access protocol to allocate resources to subscribers in an interactive, multimedia, broadband satellite communications system. The method first provides a plurality of channels with at least one of said plurality of channels being assigned to each of a plurality of terminals. The method then monitors the utilization of the channel resources by the plurality of terminals. An evaluation is conducted of system needs based on the levels of activity and utilization of channel resources by the terminals. Requests for system resources by the terminals are communicated to a resource controller which calculates the system needs. Finally, the method utilizes the resource controller to adjust the channel resources based on the levels of activity and utilization of resources by the terminals.
In the preferred embodiment, the adjustment provides active terminals as much resources as required during duration of their activity, subject to resource availability. Additionally, the MAC protocol implemented is a multimedia circuit switched MAC protocol tailored to a geostationary satellite communications system environment.
The above as well as additional objects, features, and advantages of the present invention will become apparent in the following detailed written description.

Activity based resource assignment medium access control protocol


According to an embodiment, a reinforcement learning system includes a memristor array in which each of a plurality of first direction lines corresponds to one of a plurality of states, and each of a plurality of second direction lines corresponds to one of a plurality of actions, a first voltage application unit that individually applies voltage to the first direction lines, a second voltage application unit that individually applies voltage to the second direction lines, a action decision circuit that decides action to be selected by an agent in a state corresponding to a first direction line to which a readout voltage is applied, a action storage unit that stores action selected by the agent in each state that can be caused in an environment, and a trace storage unit that stores a time at which the state is caused by action selected by the agent.

Recently, an artificial intelligent technique has been rapidly developed along with the progress of computer hardware represented by a graphical processing unit (GPU). In particular, an image recognition/classification technique represented by a convolutional neural network (CNN) has been already used in various scenes in the real world. On the other hand, among artificial intelligent techniques, reinforcement learning in which not only recognition and classification of signals are simply performed but also a system itself learns and smartens while repeating trials attracts attention. For example, the reinforcement learning is applied to an algorithm mounted in AlphaGo that has defeated a human professional go player.
In this manner, reinforcement learning in which a system itself can perform determination and operations that are based on creative and strategic thinking, by trial and error attracts attention as a basic technique of an edge device such as future autonomously operating mobility or a robot. Nevertheless, reinforcement learning requires complicated and enormous calculations. In other words, in reinforcement learning, action selection of an agent that corresponds to a state of an environment, and state transition of the environment that is caused by the action are repeated, and a probability of selecting the action in the environment is changed according to whether a desired result has been obtained, while tracing back the history of action selection and state transition. Thus, reinforcement learning requires large memory and calculation amount, and is difficult to be mounted on an edge in which a calculation resource and power consumption are restricted.
On the other hand, there is proposed a technique of causing a neural network to learn without individually accessing memristors, by forming the neural network like hardware using a crossbar memristor array, and devising a voltage sequence. Because parallelism of neural network learning can be enhanced by this technique, power consumption in learning can be considerably improved. Nevertheless, while this technique can perform learning of static data such as image recognition, this technique cannot be directly applied to reinforcement learning handling time-series data because it is necessary to trace back the history of action selection of an agent and state transition of an environment as described above.


A dental patient hand held vibrating device having a interdental mouthpiece portion for insertion into the mouth for gripping between the teeth of the dental patient encountering discomfort resulting from the adjustment of their orthodontic appliances. The hand held device comprises a housing containing a battery and a switch for selectively operating a motor with an off center weight attached to the motor rotating shaft for creating a high frequency vibration that vibrates the entire device. The vibration is transferred from the body of the device to the interdental mouthpiece held between the teeth of the patient. The vibrating interdental mouthpiece reestablishes an adequate blood supply to the teeth and surrounding periodontal structures so as to substantially eliminate the discomfort encountered by a patient that has had their orthodontic appliance adjusted.

The invention relates to hand held apparatus for utilizing a vibrating interdental mouthpiece to eliminate the discomfort caused by the adjustment of the dental patient's orthodontic appliances.
There are several patents directed to various elaborate professional apparatus utilized by Dentists in their offices for multiple purpose one of which is reducing discomfort for the orthodontic patient.
U.S. Pat. Nos. 4,123,844; 4,229,165; 4,244,688; 4,348,177; 4,348,178 and 4,382,780 all by inventor Craven H. Kurz teach various apparatus and methods for the purpose of decreasing overall treatment time and reducing bone and root loss in a pain free environment. These devices appear to be complex professional dental equipment for use under the supervision of a dental professional in a dental office atmosphere.
There has not been a inexpensive portable unit that can be used by the patient in a non-dental office environment which has a disposable interdental mouthpiece that can easily be replaced if it becomes damaged or contaminated.

Hand held device for reducing the discomfort associated with the adjusting of orthodontic appliances


A method for servicing, especially checking, an apparatus for capacitive ascertaining and/or monitoring at least one process variable of a medium, wherein the apparatus has at least one probe unit with a probe electrode and an auxiliary electrode. The probe electrode and/or the auxiliary electrode are/is supplied at least with one test signal or connected with at least one electrical potential, that at least one response signal is tapped from the probe unit, and that, at least from the response signal and a predeterminable desired value, information is obtained concerning the apparatus.

In process and automation technology, it is known to ascertain or monitor the fill level of a medium by means of the capacitive measuring method. In such method, a probe unit and the wall of the container, or the probe unit and a second probe unit, form, together with the medium as dielectric, a capacitor. The capacitance of this capacitor is measured, and, on the basis of the measured value, fill level is ascertained. Problematic with this method is that the probe unit comes in contact with the medium and that, therefore, accretions can build on the probe unit. Such accretion leads to degradation of the measurement or even prevents measurement. In the state of the art, it is known to supply the probe unit with a relatively high measuring frequency (e.g. greater than 1 MHz), in order to improve accretion tolerance. Disadvantageous in the case of a high measuring frequency is that such is associated with a decrease in the maximum allowable probe length. This is because frequency-dependent resonance effects arise on the probe, which prevent linear measurement.
In the case of accretion formation between container wall and probe unit, a further possibility is to use so-called guard electrodes, which lie at the same electrical potential as the probe electrode and surround the probe electrode (see e.g. DE 32 12 434 C2). Depending on the character of the accretion, it is, however, possible that there will be difficulties with suitable production of the guard signal (DE 10 2004 050 495 A1).
In this case, the probe unit is thus composed of a probe electrode and an auxiliary electrode, with the probe electrode serving for the actual measurement and the auxiliary electrode serving as guard.
In the modern measurements technology, it is evermore required that prospective self tests of a measuring device be performed. In this way, for example, early warnings are possible, before the measuring device fails or before the measurement results could become unreliable.

Method for servicing an apparatus for capacitive ascertaining and/or monitoring of a process variable


A capsule comprising two non-directly contacting halves enables otherwise coupling loads between experiment and gauging to be re-routed through the outer-most portable body (e.g. a logging sonde housing) having substantial inertia, thus serving to attenuate the parasitic loads. For co-located leveled experiment and gauging, a pair of concentric bearings (shaft in shaft) is utilized. Independent bearing sets and shock/vibration isolation support each capsule half within the outer sonde housing. A first half of the capsule supports the experiment, which the second half supports the gauging apparatus.

During hydrocarbon drilling or mining, the gradient acceleration of a mass due to gravity is measured and used to gain information about the density of geological formations below the ground's surface. Measurement of the acceleration of a mass due to the force of gravity is performed by repeatedly dropping the mass and measuring variations of the drop of the mass during freefall. When performing the gravity measurement experiments, forces acting on the mass (force loop) and the forces affecting the instrumentation used to measure the gravity effects (measurement loop) may interact, causing part of the recoil force produced as a reaction to the gravitation force on the mass, to transfer to the measurement instrumentation, thereby resulting in self-induced interference and degradation of the measurement results.
Decoupling the force and measurement loops is a basic pursuit when designing ultra-precision instrumentation. Assuming the force and measurement loops could be completely decoupled, the gauging instruments would have no influence on the experiment and vice versa. However, in practice, absolute decoupling is impracticable and the design objective therefore becomes one of minimizing the self-induced disturbances or interference. For some applications, a measure of self-induced interference is tolerated. However, some experiments require extremely precise measurements and at such minute scale (for example 1 micro-Gal) that the self-induced interference produces noise to signal ratios that prevent the desired signal from being measurable. Certain precision experiments may be carried out in specially designed test platforms that operate in zero gravity environments such as in outer space. While this avoids the need to support the static weight of relevant apparatus, thereby providing an alternative means of decoupling, operating in zero gravity environments is expensive, forcing the experimenter to purchase space on a vehicle (e.g. a satellite, rocket, and/or space station) appropriate for conducting the experiment.
Space limitations are also a factor. The miniaturization of gravimeters requires spatial overlapping force and measurement loops, thereby compounding the difficulty in preventing crosstalk between the loops. Alternate means of reducing parasitic effects of force and measurement loop coupling are desired in an apparatus small enough to be used in drilling, logging, or monitoring operations, such as down hole in a sensor device such as a logging sonde,

Loop de-coupling capsule for hosting ultra-sensitive experiments in a logging sonde


A communication device includes a communication unit configured to receive first path information from a first vehicle and to receive second path information from a second vehicle, and a processor configured to determine a possibility of the first and second vehicles entering a predetermined area based on the first and second path information, and based on the possibility being greater than a reference, transmit a message for controlling at least one of the first vehicle or the second vehicle through the communication unit to allow the first and second vehicles to enter the predetermined area at different time points.

A vehicle may transport people or goods by using kinetic energy. Examples of vehicles include automobiles and motorcycles.
In some examples, for safety and convenience of a user who uses the vehicle, the vehicle may include various sensors and devices, and functions of the vehicle may be diversified.
The functions of the vehicle may be divided into a convenience function for promoting driver's convenience, and a safety function for enhancing safety of the driver and/or pedestrians.
The convenience function may include providing infotainment (information+entertainment) to the vehicle, supporting a partially autonomous driving function, or helping the driver ensuring a field of vision at night or at a blind spot. For example, the convenience functions may include various functions, such as an active cruise control (ACC), a smart parking assist system (SPAS), a night vision (NV), a head up display (HUD), an around view monitor (AVM), an adaptive headlight system (AHS), and the like.
The safety function for ensuring safety of the driver and/or pedestrians may include various functions, such as a lane departure warning system (LDWS), a lane keeping assist system (LKAS), an autonomous emergency braking (AEB), and the like.
For convenience of a user using a vehicle, various types of sensors and electronic devices may be provided in the vehicle. For example, a vehicle may include an Advanced Driver Assistance System (ADAS). In some cases, the vehicle may be an autonomous vehicle.
The advanced driver assistance system (ADAS) may be improved for user's convenience and safety while driving a vehicle.
For example, in order to effectively transmit electronic Horizon (eHorizon) data to autonomous driving systems and infotainment systems, the European Union Original Equipment Manufacturing (EU OEM) Association has established a data specification and transmission method as a standard, namely "Advanced Driver Assistance Systems Interface Specification (ADASIS)."
In some cases, eHorizon software may be an integral part of safety/ECO/convenience of autonomous vehicles in a connected environment.

Communication device, control method thereof, and communication system including the same


A novel clock synchronization mechanism for recovering and distributing a centralized clock source synchronously over asynchronous networks such as optical Ethernet. A clock conversion scheme is provided whereby multiple clocks having diverse rates are converted to clock signals all having a common rate. One of the converted clocks is chosen and all downstream clock signals is derived from this clock. A high quality clock source located anywhere on the network is distributed throughout the network thus turning an asynchronous Ethernet network into a synchronous one. Synchronous TDM data streams can then be easily transported over the Ethernet network.

The growth in demand for telecommunication services is increasing at an ever-quickening pace. The majority of the demand is being driven by the explosion in the use of the Internet and a steady stream of new applications being introduced which further increase the demand for increased bandwidth. Currently, a large portion of the Internet traffic is still carried by circuit switched transport facilities. In the case of Metropolitan Area Networks (MANs), most of the traffic is transported over SONET/SDH based networks most of which were originally resigned designed for voice traffic.
The requirements for networked communications within the user community have changed dramatically over the past two decades. Several notable trends in the user community include (1) the overwhelming domination of Ethernet as the core networking media around the world; (2) the steady shift towards data-oriented communications and applications; and (3) the rapid growth of mixed-media applications. Such applications include everything from integrated voice/data/video communications to the now commonplace exchanges of MP3 music files and also existing voice communications which have begun to migrate towards IP/packet-oriented transport.
Ethernet has become the de facto standard for data-oriented networking within the user community. This is true not only within the corporate market, but many other market segments as well. In the corporate market, Ethernet has long dominated at all levels, especially with the advent of high-performance Ethernet switching. This includes workgroup, departmental, server and backbone/campus networks. Even though many of the Internet Service Providers (ISPs) in the market today still base their WAN-side communications on legacy circuit oriented connections (i.e. supporting Frame Relay, xDSL, ATM, SONET), their back-office communications are almost exclusively Ethernet. In the residential market, most individual users are deploying 10 or 100 Mbps Ethernet within their homes to connect PCs to printers and to other PCs (in fact, most PCs today ship with internal Ethernet cards) even though the residential community still utilizes a wide range of relatively low-speed, circuit-oriented network access technologies.
The use of Ethernet, both optical and electrical based, is increasing in carrier networks due to advantages of Ethernet and in particular Optical Ethernet, namely its ability to scale from low speeds to very high rates and its commodity-oriented nature. With the rapid increase in the demand for user bandwidth, and the equally impressive increase in the performance of Ethernet with the LAN environment, the demand for Metropolitan network performance is rapidly increasing. In response, there has been a massive explosion in the amount of fiber being installed into both new and existing facilities. This is true for both the corporate and residential markets.
A problem arises from the fact that conventional Ethernet networks are designed to transfer packets from one location to another asynchronously. Conventional Ethernet networks lack a mechanism for providing clock synchronization and distribution from a centralized clock source location. They are not capable of conveying information synchronously and thus cannot support TDM traffic streams, for example. In an asynchronous network, each node in the network generates its clock independently from all other nodes. Currently, if there is a need to transfer clocking information such as TDM traffic, other network types can be used, such as synchronous networks wherein an accurate clock source is distributed around the network. An example of a synchronous network is the well known Synchronous Optical Network (SONET)/Synchronous Data Hierarchy (SDH) network. In a SONET network, a high quality clock is distributed over the synchronous network. Existing SONET/SDH networks perform clock synchronization and distribution over a TDM based network. A short description of SONET follows.
The synchronous optical network, commonly known as SONET, is a standard for communicating digital information using lasers or light emitting diodes (LEDs) over optical fiber as defined by GR-253-CORE. It was developed to replace the Plesiochronous Digital Heirarchy (PDH) system for transporting large amounts of telephone and data traffic and to allow for interoperability between equipment from different vendors. The more recent synchronous digital hierarchy (SDH) standard developed by the International Telecommunication Union (ITU) is built on experience in the development of SONET. It is documented in standard G.707 and its extension G.708. Both SDH and SONET are widely used today; SONET in the United States and Canada, SDH in the rest of the world.
SONET differs from PDH in that the exact rates that are used to transport the data are tightly synchronized across the entire network, made possible by atomic clocks. This synchronization system allows entire inter-country networks to operate synchronously, greatly reducing the amount of buffering required between each element in the network.
Another circuit type used more and more in data networking equipment is 10 Gigabit WAN Ethernet (10 G-WIS). This is similar in rate to OC-192/STM-64, and, in its wide area variant, encapsulates its data using a light-weight SONET/SDH frame so as to be compatible at low level with equipment designed to carry those signals. 10 Gigabit LAN Ethernet, however, does not explicitly provide any interoperability at the bitstream level with other SONET/SDH systems. This differs from WDM system transponders, including both coarse- and dense-WDM systems that currently support OC-192 SONET Signals, which can normally support thin-SONET framed 10 Gigabit Ethernet.
Regarding synchronization of SONET and SDH networks, a SONET NE transports and/or multiplexes traffic that has originated from a variety of different clock sources. In addition, a SONET NE will typically have a number of different synchronization options to choose from, which in some cases it will do so dynamically based on Sync Status Messages and other indicators.
The synchronization sources available to a SONET NE typically include:
1. Local external timing generated by an atomic Cesium clock or a satellite-derived clock by a device located in the same central office as the SONET NE. The interface is typically DS1 with Sync Status Messages supplied by the clock and placed into the DS1 overhead.
2. Line-derived timing whereby a SONET NE can be configured to derive its timing from the line-level, by monitoring the S1 sync status bytes to ensure quality.
3. Using holdover wherein, in the absence of higher quality timing, a SONET NE uses its own timing circuits to time the SONET signal until a higher quality external timing becomes available again.
A disadvantage of using a SONET/SDH network for clock synchronization is the high cost of such networks. A further disadvantage is that having been developed for TDM networks, SONET/SDH networks are not optimized for Ethernet transport which transmits data asynchronously.
Thus, a problem exists in how to transfer legacy TDM traffic over an asynchronous Ethernet network and particularly, how to extract and reconstruct the TDM clock from the received data at the other side. It is important that the clock used at the receive side be traceable to the clock used at the transmitter. The clock at the transmitter side can be provided from an external source, a clock distribution network or from SONET/SDH equipment.
One prior art solution is to break the TDM traffic into several channels and convert the voice data to IP packets using DSP algorithms and then switch this IP traffic over the network. This approach, however, does not address transporting TDM traffic over asynchronous Ethernet networks.
Other schemes attempt to recover the TDM clock by maintaining a buffer and a pointer whereby if the slave clock is following the master clock, the pointer is designed to stay in the mid point of the buffer. Deviations of the slave clock from the master clock cause the pointer to move away from the mid point of the buffer. The location of the pointer is monitored and suitable action taken if it is detected to have moved.
A disadvantage of this scheme, however, is that the jitter and wonder generated is relatively high and typically does not meet common carrier telecommunication standards. In addition, the scheme cannot track the master clock in the event a large number of packets are lost and is overly sensitive to lost and erroneous packets.
Alternatively, an algorithmic approach can be used to transfer a clock. In this clock reconstruction mechanism, synchronous TDM communications traffic is transported over asynchronous networks such as Ethernet networks. The network comprises edge switches in Metropolitan Area Networks (MANs) that transport legacy TDM traffic using a Circuit Emulation Services (CES) module whereby TDM traffic is encapsulated and transported across the Ethernet network where it is de-encapsulated and clocked out to the destination. The input TDM data stream is encapsulated into Ethernet packets and a network timestamp is inserted into the packet. At the destination CES, a local timestamp is generated for each received packet as it is received. The network timestamp is extracted and input along with the local timestamp to a Digital Time Locked Loop (DPLL) which is operative to accurately reconstruct the original transmit TDM clock.
The clock quality output from this mechanism is, however, of medium quality. In addition, it is susceptible to network delays and congestion. A more detailed description of the algorithmic approach can be found in U.S. Pat. No. 7,289,538, entitled "Clock Reconstruction for Time Division Multiplexed Traffic Transported Over Asynchronous Ethernet Networks," incorporated herein by reference in its entirety.
There is thus a need for a clock synchronization and distribution mechanism operative over an asynchronous network such as Ethernet that overcomes the disadvantages of the prior art. The mechanism should be capable of passing a high quality clock over an Ethernet physical network by making the network synchronous. Preferably, the mechanism is relatively straightforward to implement and is cost effective to make its use practical.

This patent is subject to a terminal disclaimer.

Clock synchronization and distribution over an optical Ethernet network


A spread spectrum demodulator for use with a phase-shift-keying modulated spread spectrum signal used in mobile satellite communications. An objective of the spread spectrum demodulator is to perform tracking by producing from a correlation pulse signal an error signal having a time discrimination characteristic. The spread spectrum demodulator generates from the correlation pulse signal an error signal whose level varies in response to a phase difference between a pseudonoise signal contained in a received signal and a reference pseudonoise signal. A clock in synchronism with the received signal is generated from this error signal, thereby demodulating the received signal.

1. Field of the Invention
This invention relates to a spread spectrum demodulator of a direct sequence type spread spectrum system.
2. Description of Related Arts
A spread spectrum demodulator for use with a phase-shift-keying modulated spread spectrum signal disclosed, for example in the article entitled "YOKOYAMA SPREAD SPECTRUM COMMUNICATION SYSTEM" by Kagaku Gijyutsu Syuppan Sha (in 1988), has been known as a spread spectrum demodulator of the conventional direct sequence type spread spectrum system. FIG. 16 of the accompanying drawings diagrammatically represents a block diagram of the conventional spread spectrum demodulator.
In the drawing, reference numeral 1 designates a received signal; 2, an initial acquisition circuit for generating from the received signal a signal (hereinafter referred to as acquired signal) which represents a breakpoint of information data bits; 3, an acquired signal; 4, a tracking circuit for effecting tracking in response to the acquired signal; 5, a reproduced pseudo noise signal (hereinafter referred to as PN signal); 6, a mixer for multiplying the received signal by the reproduced PN signal; 7, a despreading section comprised of the initial acquisition circuit 2, the tracking circuit 4, and the mixer 6; 8, a despread signal which does not contain a PN signal component; 9, a PSK demodulator; and 10, demodulated data.
The outline of the operation of the demodulator shown in FIG. 16 will now be described. Assuming that the received signal is a spread spectrum signal whose carrier wave, having a frequency of .omega..sub.0, is modulated by BPSK (Binary Phase-shift Keying), the spread spectrum signal is then expressed as EQU d(t)c(t)cos.omega..sub.0 t (1).
In this equation, d(t) is an information data signal having a bit width of Td and is designated as a rectangular wave signal having a value of -1 or +1, and c(t) is a PN signal (hereinafter, one bit of the PN signal is called a chip) having the bit width of Tc and is designated as a rectangular wave signal having a value of -1 or +1. N chips of the PN signals constite one cycle of a M series code. Spreading one bit of information data with one cycle of the PN signal results in Td=NTc.
The initial acquisition circuit 2 detects from the received signal 1 a timing signal corresponding to a breakpoint of the information data bits and outputs the thus detected timing signal to the tracking circuit 4 as the acquired signal 3. The tracking circuit 4 generates the reproduced PN signal 5 from the acquired signal 3. Despite the fact that the reproduced PN signal 5 is out of phase with the PN signal included in the received signal 1 before a time when the acquired signal 3 is received, namely, c (t+.tau.), the tracking circuit 4 generates the reproduced PN signal 5 in synchronism with the received signal of .tau.=0 based on the timing when the acquired signal 3 is received, and thereafter tracks the status of .tau.=0.
The multiplier 6 multiplies the received signal 1 by the reproduced PN signal 5, which results in c(t).times.c(t)=1. Hence, there will be obtained the despread signal 8 which does not contain the PN signal component the despread signal being expressed as EQU d(t) cos .omega..sub.0 t (2)
The general PSK demodulator 9 demodulates the despread signal 8 and produces the demodulated data 10.
The feature of the spread spectrum demodulator lies in the despreading section 7 comprised of the initial acquisition circuit 2, the tracking circuit 4, and the mixer 6. The initial acquisition circuit 2 and the tracking circuit 4 both of which are components of the despreading section 7 will now be described with reference to FIGS. 17, 18, and 19.
FIG. 17 shows the structure of the initial acquisition circuit of the conventional spread spectrum demodulator disclosed in the book entitled "SPREAD SPECTRUM COMMUNICATIONS, Vol. 3", by M. K. Simon, COMPUTER SCIENCE PRESS (1985).
In the drawing, reference numeral 1 designates the received signal; 11, a carrier wave generator; 12A and 12B, mixers; 13A and 13B, low pass filters (LPF); 13a, a base band signal generated using the carrier wave which was generated by the carrier wave generator 11; 13b, a base band signal generated by use of the Carrier wave having a phase delay of 90.degree.; 14A and 14B, sampling circuits for sampling the base band signals 13a and 13b, respectively; 14a and 14b; sampled signals, each sampled by the sampling circuit; 15A and 15B, correlators for correlating the sampled signals 14a and 14b with a PN signal (hereinafter, referred to as reference PN signal) which has been preset by the demodulator; 15a and 15b, correlation signals outputted from the correlators; 15A and 15B respectively; 16A and 16B, square generators for producing a square of each of the correlation signals 15a and 15b; 17, a phase shifter for causing a 90.degree. phase delay of the carrier wave outputted from the carrier wave generator 11; 23, an adder for adding the squares of the correlation signals produced by the square generators 16A and 16B; 24, a correlation pulse signal outputted from the adder 23; and 25, a decision device for generating the acquired signal 3 by deciding on phase matching of the PN signal components included in the received signal 1 and the reference PN signal.
The operation of the initial acquisition circuit shown in FIG. 17 will now be described.
The function of the initial acquisition circuit is to generate the acquired signal 3 at a timing such that the PN signal included in the received signal 1 that was received with distortions due to adverse noise effects of along the transmission path is in phase with the reference PN signal. This is achieved by comparing these two signals.
Given that a phase difference between a carrier wave of the received signal 1 and a carrier wave outputted from the carrier wave generator 11 is 8, the carrier wave outputted from the carrier wave generator can be expressed as EQU cos(.omega..sub.0 t+.theta.).
In the meantime, a carrier wave outputted by way of the 90.degree. phase shifter 17 is EQU sin(.omega..sub.0 t+.theta.).
The received signal 1 is divided into two, and the one signal is multiplied by the carrier wave cos (.omega..sub.0 t+.theta.) which is outputted from the carrier wave generator 11 by means of the mixer 12A, then converted by means of the low pass filter 13A into the base band signal 13a which includes cos.theta. components. The other signal is multiplied by the carrier wave sin (.omega..sub.0 t+.theta.) that is outputted by way of the 90.degree. phase shifter 17 by means of the mixer 12B, then converted by means of the low pass filter 13B into the base band signal 13b which includes sin.theta. components.
The base band signals 13a and 13b are sampled by the sampling circuits 14A and 14B, and transmitted to the correlators 15A and 15B, respectively.
Because of the use of an asynchronous clock in the above sampling operation, sampling is usually performed twice per chip. Consequently, supposing a chip width Tc of the PN signal, a sampling interval will be given as Tc/2. The correlators 15A and 15B correlate sampled signals which were sampled during a period equivalent to one cycle of the PN signal with the reference PN signals. Since one cycle of the PN signal is N, the number of each of the sampled signals 14a and 14b having been subjected to sampling during a period equivalent to one cycle of the PN signal is 2N. Sampling per twice chip results in a sampled signal having the same PN signal adjacent to the sampled signals 14a and 14b, and the correlators 15A and 15B generate correlation signals as expressed below, making use of 2N sampled signals having been inputted thereto. ##EQU1## where .gamma.i (i=1, . . . , 2N) is 2N sampled signals to be inputted, cj is the reference PN signal having a value of either -1 or +1, and [n] is the maximum integer which does not exceed n. The correlators can be said to be circuits which generate an auto correlation of the PN signal.
Next, referring to FIG. 2, the relationship between the base band signals 13a and 13b subjected to sampling performed twice per chip and a sampling timing will be described. Presume that a time t=iTC (i=1, 2, . . . ) is the center of each chip waveform, that times when two sampling timings of each chip respectively offset +.DELTA.t from two timings (iTc-Tc/4) and (iTc+Tc/4) symmetrical with the center of the each chip waveform are defined as t.sub.1 (=iTc-Tc/4+.DELTA.t) and t.sub.2 (=iTc+Tc/4+.DELTA.t), and that the sampling circuits 14A and 14B sample the analog quantity of input signals as they are, the sampled signals 14a and 14b sampled at the timing t.sub.2 are respectively expressed as follows. EQU d(t.sub.2)c(t.sub.2)h(Tc/4+.DELTA.t)cos.theta. (4) EQU d(t.sub.2)c(t.sub.2)h(Tc/4+.DELTA.t)sin.theta. (5)
where h (t.sub.0) represents a unit pulse waveform of a chip which is characterized by the characteristic of the low pass filters 13A and 13B, and h(.sub.0) corresponds to the center of the chip waveform.
If c(t.sub.2) is rewritten into ci (having a value of -1 or +1), the sampled signals 14a and 14b sampled at the timing of t.sub.2 can be expressed as EQU d(t.sub.2)c.sub.i h(Tc/4+.DELTA.t)cos.theta. (6) EQU d t.sub.2)c.sub.i h(Tc/4+.DELTA.t)sin.theta. (7)
The relationship between the correlation signals 15a and 15b and the sampling timing will now be explained with reference to FIG. 3.
At a sampling timing ts (=kNTc+Tc/4+.DELTA.t), (k=1, 2, . . . ), the correlators 15A and 15B correlate 2N sampled signals 14a and 14b from a timing tu (={(k-1) N+1} Tc-Tc/4+.DELTA.t) to a timing ts (=kNTc+Tc/4+.DELTA.t).
Each of 2N number of sampled signals 14a and 14b contains two PN signal components from c.sub.1 to c.sub.N. Since each sampled signal contains c.sub.1, c.sub.1, c.sub.2, c.sub.2, . . . , c.sub.N, c.sub.N, the PN signal component comprised in the received signal 1 at the sampling time ts is matched with the reference PN signal.
Accordingly, the correlation signals 15a and 15b will be signals from which the PN signal components have been respectively eliminated, as expressed by c.sub.i .times.c.sub.1 =1. ##EQU2##
If one information data bit is spread by the PN signal, the information data does not change within one cycle of the PN signal. Hence, if d ((k-1) NTc+iTc-Tc/4+.DELTA.t) and d((k-1) NTc+iTc+Tc/4+66 t) are represented as d.sub.k (having a value of -1 or +1), the correlation signals 15a and 15b at the sampling timing ts when the PN signal components included in the received signal 1 and the reference PN signal are completely matched with each other can be expressed as EQU Nd.sub.k {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}cos.theta. (10) EQU Nd.sub.k {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}sin.theta. (11)
Contrary to this, the correlation signals 15a and 15b at a timing when the PN signal components included in the received signal 1 are out of phase with the reference PN signal becomes -1 when the PN signal is M-sequence. Hence, respectively, respective these correlation signals can be represented as EQU -d.sub.k {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}cos.theta. (12) EQU -d.sub.k {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}sin.theta. (13)
Since d.sub.k .times.d.sub.k -1, the information data component d.sub.k is eliminated from the correlation signals 15a and 15b by squaring the signals by means of the square generators 16A and 16B. Thereafter, the correlation pulse signal 24 is produced by adding the correlation signals 15a and 15b at the adder 23.
As a result of this, the correlation pulse signal 24 does not include any information data components, and is represented by the following equation at the timing ts when the PN signal components included in the received signal 1 is completely matched with the reference PN signal. EQU N.sup.2 {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}.sup.2 ( 14)
Contrary, the correlation pulse signal 24 is represented by the following equation at a timing when the PN signal components included in the received signal 1 is out of phase with the reference PN signal. EQU {h(-Tc/4+.DELTA.t)+h(+Tc/4+.DELTA.t)}.sup.2 ( 15)
Since a PN signal having a large cycle of N is commonly used in spread spectrum communications, there consequently arises a large difference between the amplitude of the correlation pulse signal 24 produced at the time when the received PN signal is in phase with the reference PN signal and the amplitude of the correlation pulse signal 24 produced at the time when these signals are out of phase with each other.
The decision device 25 decides a generation timing of the acquired signal 3 making use of the above mentioned characteristics, and outputs the acquired signal 3, thereby completing the initial acquisition operation.
Subsequently, the acquired signal 3 thus generated by the initial acquisition circuit is transmitted to the tracking circuit 4 shown in FIG. 16, and thereafter tracking of the PN signal included in the received signal 1 is effected. A conventional tracking circuit 4 will be described hereinbelow.
FIG. 18 shows the structure of the conventional tracking circuit used in the spread spectrum demodulator shown in the aforementioned documents written by M. K. Simon.
In FIG. 18, reference numerals 26A and 26B designate multipliers for multiplying the received signal 1 by an early PN reference signal 39 and a late PN reference signal 40 respectively, both being generated by a PN signal generator 38; 27A and 27B, band-pass filters (BPF) having a center frequency equivalent to the carrier frequency of the received signal 1; 28A and 28B, square generators; 34, a subtracter for producing a difference of levels between the output of the square generators 28A and 28B; 35 and 35a, error signals; 36, a loop filter; 37, a voltage controlled oscillator for generating a reproduced clock 37a by varying an output frequency by use of a voltage of the error signal 35a; 38, a PN signal generator for generating the early and the late PN reference signals 39, 40 from the reproduced clock 37a; and 41, a delay element for causing the Tc/2 period delay of the early PN reference signal 39.
A description will be given of the tracking circuit shown in FIG. 18.
Upon receipt of the acquired signal 3, the PN signal generator 38 starts outputting both the early PN reference signal 39 and the late PN reference signal 40. The early PN reference signal 39 is advanced in phase by Tc/2 with respect to the punctual PN reference signal 5, whilst the late PN reference signal 40 is delayed in phase by a Tc/2 with respect to the punctual PN reference signal 5.
Assume that the punctual PN reference signal 5 is delayed in phase by a time, .tau., with respect to the phase of a PN signal c(t) included in the received signal 1. The punctual PN reference signal 5 designated by S.sub.R (t), the early PN reference signal 39 designated by S.sub.E (t), and the late PN reference signal 40 by S.sub.L (t) are characterized by the following equations. EQU S.sub.R (t)=c(t-.tau.) (16) EQU S.sub.E (t)=S.sub.R (t+Tc/2)=c(t-.tau.+Tc/2) (17) EQU S.sub.L (t)=S.sub.R (t-Tc/2)=c(t-.tau.-Tc/2) (18)
The received signal 1 (=d (t) c (t) cos.omega..sub.0 t) is divided into two, and one half is multiplied by the early PN reference signal S.sub.E (t) by means of the mixer 26A, and the thus obtained signal is inputted in the band-pass filter 27A. The band-pass filter 27A passes a signal whose spectrum band width is within that of the information data d(t). This filter is inserted in order to eliminate unwanted noise components received together with the received signal 1. Instantaneous value components c (t) c (t-.tau.+Tc/2) included in the signal outputted from the band-pass filter 27A are eliminated by the characteristic of a loop which constitutes the tracking circuit that suppresses a high frequency component, leaving an average of a result from the multiplication of the PN signal contained in the signal outputted from the band pass filter 27A. This average value results in a signal expressed as below. EQU d(t)c(t)c(t-.tau.+Tc/2 cos.omega..sub.0 t (19)
where c (t) c (t-.tau.+Tc/2) represents a time average of c (t) c (t-.tau.+Tc/2 component.
The time average of the c (t) c (t-.tau.+Tc/2) represents the autocorrelation function of the PN signal, and shows a maximum value rate Tc/2 and a minimum value -1 at .vertline..tau.-Tc/2 .vertline..gtoreq.Tc.
Assume that the autocorrelation function is R.sub.E (.tau.), then the R.sub.E (.tau.) is expressed as ##EQU3##
Squaring the output signal from the band-pass filter 27A by means of the square generator 28A results in elimination of the information data component d(t). Despite the fact that squaring the carrier frequency component w.sub.0 causes generation of a DC component and a 2w.sub.0 component, the characteristic of the loop which constitutes the tracking circuit for suppressing the high frequency component allows the elimination of the 2w.sub.0 components, eventually the DC component simply appearing at the output of the band-pass filter 27A.
As a result of this, the signal 29a outputted from the square loop 28A becomes {R.sub.E (.tau.)}.sup.2. The other half of the divided received signal 1 is multiplied by the late PN reference signal S.sub.L (t) by means of the mixer 26B, and then transmitted to the band-pass filter 27B. The output signal of the bandpass filter 27B is then expressed as EQU d(t)c(t)c(t-.tau.Tc/2)cos.omega..sub.0 t(k=1, 2, . . . ) (21)
Suppose the autocorrelation function of the PN signal which is included in the above signal is R.sub.L (.tau.), the R.sub.L (.tau.) will be represented as ##EQU4##
Squaring the output signal from the band-pass filter 27B by means of the square loop 28B results in the signal 29b represented as {R.sub.L (.tau.)}2.
The subtracter 34 generates the error signal 35 from the signals 29a and 29b, and this error signal is then subjected to elimination of unwanted noise by the loop filter 36, producing the error signal 35a. The error signals 35 and 35a are expressed by the following equation. EQU D(.tau.)={R.sub.E (.tau.)}.sup.2 -{R.sub.L (.tau.)}.sup.2 ( 23)
FIG. 19 shows the amplitude characteristic of the error signals 35 and 35a. Thus, the error signals are configured in S shape symmetry with respect to the origin of coordinates, and have a characteristic to produce D (.tau.)>0 with .tau.>0 and D (.tau.)<0 with .tau.<0. Such characteristics are hereinafter referred to as a time discrimination characteristic.
The voltage controlled oscillator 37 produces an output of the reproduced clock 37a having a frequency corresponding to the amplitude of the error signals. In response to the output from the voltage controlled oscillator 37, the PN signal generator 38 outputs both the early and late PN reference signal 39 and 40.
This operation is effected in such a manner as to maintain the value .tau. of 0, and hence the early PN reference signals 39 is in synchronism with the PN signal included in the received signal 1 which is phase advanced by Tc/2, whereas the late PN reference signal 40 is in synchronism in phase delayed by Tc/2.
The early PN reference signal 39 is delayed by a period of Tc/2 by means of the delay element 41 and outputted as the punctual PN reference signal 5 completely in phase with (.tau.=0) the PN signal components included in the received signal 1.
As mentioned above, the PN signal components included in the received signal 1 shown in FIG. 16 are eliminated (despread) using the punctual PN reference signal 5 which was generated by the tracking circuit, and subsequently the information data is demodulated by means of the conventional PSK demodulator 9.
In the conventional spread spectrum demodulator apparatus having the foregoing structure, the initial acquisition circuit performs initial acquisition using a received signal from which PN signal components have been eliminated, and the tracking circuit exercises tracking using the received signal from which the PN signal components have been eliminated in the same manner.
Thus, in the conventional spread spectrum demodulator, the operation of eliminating a PN signal component included in the received signal which is performed by the initial acquisition circuit and the tracking circuit independently of each other has resulted in a bulky apparatus with a complex structure.
In the case where the conventional spread spectrum demodulator finds application in the fields of mobile satellite communications such as mobile telephones and the like, a plurality of signals (hereinafter referred to as a multipath waveform) having different propagation delays are received at the same time, and the level of each received signal varies with time. If tracking is effected for only one of these signals, a sharp drop in the level of the received signal of interest will occur, even down to 0, when the received signal that is the target of the tracking is interfered with obstacles such as buildings. Eventually, a lack of error signals which are necessary in tracking, namely a drop of the amplitude of the error signals to zero, causes asynchronization (what is called locking-off) due to the improper tracking. The locking-off makes demodulation of information data impossible.


A temporary wheel support for a snowmobile having at suspension and least one ski attached to the suspension via a bolt having a threaded portion. The temporary wheel support comprises a main body having a first and second opposed surfaces, the first surface having therein a threaded hole configured to be screwed onto the threaded portion of the bolt and a support member extending from the second surface, the support member having a top and a bottom recess support surfaces and an end wall. The support member is configured such that an associated wheel can be removably mounted thereon and held in place by the second opposed surface and the end wall, the wheel having ball bearings in contact with the top recess support surface in a non-weight-bearing configuration and in contact with the bottom recess support surface in a weight-bearing configuration.

Snowmobiles are designed to travel over snowy or icy surfaces and are thus equipped with a drive track for propulsion and two front skis for steering. The skis have smooth undersurfaces in order to glide over snowy or icy surfaces all the while providing control. However, the skis quickly wear when in contact with rough surfaces such as asphalt or cement, which surfaces are encountered on public roads, driveways, etc. Without any protection, the undersurfaces of the skis completely wear out in but a few thousand kilometers, which renders the snowmobile harder to control and thus less safe.
They are many inventions that allow snowmobiles to travel over snowless roads or other rough surfaces while protecting the undersurfaces of the skis from wear. However, these inventions are heavy, are not easily removable (they are left on the skis when not in use) and require tools to install or remove.
Accordingly, there is a need for a temporary wheel support for snowmobile that is light, allows for the easy installation and removal of the wheels without requiring any tools.


Provided herein is a method for diagnosing/prognosing a metastatic cancer in a subject by measuring and detecting one or more of CS-ANXA2, DCAMKL, Lgr5 or CS-ANAX2 and DCAMKL or CS-ANXA2 and Lgr5 positive circulating tumor stem cells in the subject's blood or plasma. Also provided is a method for distinguishing the presence of early stage primary cancer from advanced stage metastatic cancer in the subject by measuring and detecting AnnexinA2, CS-ANXA2 and DCAMKL−1 or Lgr5 in the blood or plasma. In addition, there is provided a method for distinguishing the presence of benign, pre-cancerous tumorous growths or cancerous tumors in the subject by measuring and detecting AnnexinA2 and circulating tumor stem cells positive for CS-ANXA2 and DCAMKL or CS-ANXA2 and Lgr5 in the blood or plasma.

Field of the Invention
The present invention relates generally to the fields of detection and diagnosis and, more specifically, to diagnosis of the presence of early stage (primary) or late stage (metastatic) cancerous tumors, using a combinatorial approach of measuring circulating tumor stem cells and serum AnnexinA2.
Description of the Related Art
Developing relatively simple, non-invasive methods for diagnosing the presence of either benign tumors, such as colonic hyperplasia, adenomatous polyps, or cancerous tumors, such as adenocarcinomas at different stages of the disease, has remained a challenge. Early stages of epithelial cancers are defined as cancerous tumors limited within the tissues of origin, e.g., primary tumors, while later stages of cancer represent metastatic growths either within the lymph nodes or at distant sites away from the primary cancerous growth, such as metastatic growths in the lung/liver of colorectal carcinomas. With the advent of sophisticated proteomics in the past 7 years, investigators discovered that AnnexinA2 (ANXA2) is increasingly expressed by epithelial tumors in relation to stage of the disease (1-16). AnnexinA2 is normally present intracellularly and performs important functions of cellular trafficking (17). However, rapidly proliferating tumor cells (especially at leading edges of tumors) express membrane-associated extracellular, cell-surface associated AnnexinA2 (CS-ANXA2) (1-3, 8, 10-16, 18). Other members of Annexin family (Annexin A4, Annexin A3) are reportedly over-expressed in ovarian cancers, and increase chemo resistance (19,20). Both tetrameric and monomeric forms of AnnexinA2 have been described on cell surface of endothelial and tumor cells (12,21).
As described above, surface-associated ANXA2 (CS-ANXA2) is increasingly expressed by many solid tumors, including colorectal (CRCs) and pancreatic cancers. ANXA2 lacks transmembrane domains and is tethered to the cell surface by binding to a 26 Kda transmembrane protein (11,31). Surface-associated ANXA2 was significantly increased in colorectal adenomas and adenocarcinomas vs corresponding normal colonic mucosa (18).
Measuring circulating tumor cells in the blood of patients is a relatively new concept for diagnosing cancer, and is as yet in its infancy (52-55). Presence of circulating tumor cells likely predicts metastasis, and can be useful for monitoring recurrence (relapse) of the disease, post-treatment (56-60). Circulating tumor cells are detected by using many different methods, including immunocytochemistry (IHC) for epithelial markers such as cytokeratine-19 (CK19), and RT-PCR analysis for cancer-cell specific transcripts (61,62). Efficiency of such tests are poor, because of the rare presence of cancer cells within a very large number of blood cells (1-1000 CTCs in 109 blood cells/ml blood). Negative selection by excluding blood cells has been used to enumerate circulating tumor cells (63). Positive selection of circulating tumor cells using antibodies (Abs) against epithelial cell surface proteins such as cell adhesion protein EpCAM is currently being used (64). Circulating tumor cells, positive for EpCAM, are captured using microfluoridic CTC-Chip devices (64) and immunomagnetic bead-based methods (18,57). Isolated circulating tumor cells are confirmed by CK19 staining or Her2 amplification (53,65). Negative staining for CD45 (a Leukocyte marker) is also used (52). It is postulated that invasive cancer cells, going through epithelial mesenchymal transition (EMT), lose expression of cell surface EpCAM (66). Thus invasive circuiting tumor cells, with the highest metastatic potential, may be under-evaluated using anti-EpCAM Abs (52, 66, 67). Besides, efficacy of different EpCAM-Abs for capturing circulating tumor cells differs significantly (68). Thus, there is a recognized need in the art for efficient and effective methods of measuring circulating tumor cells.
The presence of CTCs in the blood will not detect the presence of benign tumors at a pre-cancerous stage, such as adenomatous polyps growing in the colon of the patients. The escape of cancer cells from a pre-cancerous growth, such as adenomas, is much less likely since the basement membrane for such tumors is still intact. However, the pre-cancerous benign tumorous growths are well vascularized with blood vessels, and tumor-specific antigens can be secreted into the blood supply. Significant levels of AnnexinA2 are present in the serum of patients with breast (2,3), hepatocellular (17), and lung (79) cancers. So while one can potentially diagnose and predict the presence of cancerous tumors using the newly described assays for either circulating tumor cells or cancer specific antigens, such as Her/neu, PSA or AnnexinA2, no diagnostic tests have been described to predict the presence of pre-cancerous, benign tumors (such as colon polyps) in the patients.
There is thus a recognized need in the art for effective methods of detecting the presence of benign pre-cancerous tumors, before they convert into cancerous growths, as a preventative measure. The present invention fulfills this long-standing need and desire in the art.

Diagnosis of benign and cancerous growths by measuring circulating tumor stem cells and serum AnnexinA2

The Board of Regents of the University of Texas System


A laser printer having a manual insertion port through which a pair of lamination sheet members interposing therebetween a printed card is insertable into a sheet feed passage. The laser printer also includes a sheet supply roller, a pair of resist rollers, an image forming unit, and a fixing unit. The pair of lamination sheet members are heat-sealed together by the heat generated at the fixing unit. An operation panel is provided for selecting one of printing mode and lamination mode. If the printing mode is selected, rotation of the resist rollers is temporarily stopped so as to abut a leading edge of the sheet with the resist roller for performing skew correction. If the lamination mode is selected, the skew correction with respect to the lamination sheet members is not performed.

The present invention relates to an image forming device provided with a laminating function.
In a conventional image forming device such as a laser printer, there is provided a sheet supplying portion, a developing portion, a transfer portion, and a fixing portion. A sheet supplying portion includes a sheet supply roller for supplying an uppermost sheet of a sheet stack to the developing portion. Further, a pair of resist rollers are provided for feeding the sheet supplied from the sheet supply roller to the developing portion.
In order to eliminate a formation of a diagonal image on the sheet, the orientation of the sheet is corrected by the resist rollers before the developing operation. That is, skew correction is performed. More specifically, the rotation of the resist rollers is temporarily stopped, so that a leading edge of the sheet abuts the peripheral surface of the resist rollers. By this abutment, the leading edge of the sheet can be oriented in a direction perpendicular to the sheet feeding direction.
In the developing portion, an electrostatic latent image is formed on a photosensitive drum based on an imaging information, and a toner image corresponding to the electrostatic latent image is formed on the photosensitive drum. In the transfer portion, an image recording medium such as a sheet is interposed between the photosensitive drum and a transfer member imparted with a transfer bias voltage for transferring the toner image onto the sheet. In the fixing portion, the toner image transferred onto the sheet is fixed by heating the sheet. A sheet feed passage is provided passing successively through the transfer portion and the fixing portion.
In an electrophotographic type image forming device such as the laser printer and a facsimile machine those performing high speed printing, printing data such as text data and graphic data are transmitted from an external device such as a host computer or a personal computer. In the image forming device, the inputted printing data are developed into bit image data, and the developed bit image data are stored in a printing image buffer. In the developing portion, a line-base electrostatic latent image is successively formed on the photosensitive drum at every one dot line corresponding to one raster retrieved from the printing image buffer.
In a recent demand, a sheet protection such as a lamination becomes popular in such a manner that a rectangular sheet such as a sheet card or a drive license card printed with an image is sandwiched and hermetically sealed by a pair of transparent lamination sheet members whose size is slightly greater than the rectangular card. For the lamination process, a special lamination device is provided in which the pair of lamination sheet members are pressed and heat sealed at a relatively high temperature.
As described above, the laser printer provides the fixing portion where the sheet is nipped between a heat roller and a pressure roller so as to pressedly melt the toner which has been transferred onto the sheet. To this effect, the fixing portion is adapted to generate a heating temperature of about 150.degree. C. Thus, the fixing portion of the laser printer is available for the lamination process in terms of heating and pressing the lamination sheet members.
In this regards, there has been proposed an image forming device capable of performing lamination process by allowing the lamination sheet members to pass through the sheet feed passage if image forming process is not conducted. With this arrangement, pressing force and heat those being provided by the fixing portion can be effectively utilized.
However, if the pair of lamination sheet members interposing therebetween the card are fed along the sheet feed passage, positional misalignment may occur between the upper and lower lamination sheet members, and these two lamination sheet members are fuse-bonded together with involving wrinkles. Alternatively, air may be trapped between the lamination sheet members to provide a laminated product of low quality.

Image forming device having laminating function