A lapping sensor is provided for measuring a throat height of a thin film recording element during a mechanical lapping process. The recording element is fabricated in a photolithographic process and has a zero throat location. The lapping sensor includes a sensor device for generating an output signal indicative of the throat height during the lapping process, and a calibration switch in electrical communication with the sensor device. The switch is fabricated during the same photolithographic process as the recording element and generates an output signal during the lapping process indicative of a low resistance value up to a selected distance from the zero throat location of the recording element, and indicative of a high resistance value thereafter. Transition of the switch output signal from the low resistance value to the high resistance value during the lapping process is used to calibrate the sensor device output signal to the selected distance from the zero throat location of the recording element. A method for manufacturing the lapping sensor is also provided.

As is well known to those of ordinary skill in the art, the performance of a metal pole thin film magnetic head structure is very sensitive to the final throat heights of the individual recording elements that make up that structure. As a result, during manufacture of the magnetic head structure, the throat heights of such recording elements must be carefully controlled. This is particularly critical in tape head structures since such structures include multiple recording elements aligned in a row, all of which must function properly for the tape head to function properly.
Such control of throat heights is generally accomplished using electrical lapping sensors which monitor throat heights during mechanical lapping of the tape head structure. Such sensors are typically fabricated in the tape head structure during the same thin film photolithographic process steps used to fabricate the recording elements themselves. Indeed, in prior art thin film tape head structures, the same metal layer and photolithographic process steps used to define the recording elements are also used to define the lapping sensor element. As a result, the lapping sensor provides a sufficiently accurate measure of the recording element throat heights, especially given the lower tolerances required for the throat heights of such prior art recording elements.
However, in newer thin film tape head structures, such throat height tolerances are tighter, and the electrical lapping sensors cannot be fabricated at the same time as the recording elements. In such structures, during thin film processing, the position of the "zero" throat is set by a baked photoresist "planar" insulating film layer, while the electrical lapping sensor is patterned in a metal film layer. The different photolithographic patterning steps between the lapping sensor and the photoresist planar introduces an alignment error. Depending on equipment and processing, this alignment error could vary anywhere from 0.5 up to 2.0 .mu.m.
Such newer thin film tape head structures, however, require recording element throat heights controlled to approximately 2.0 to 3.0 .mu.m, with tolerances of less than 0.5 .mu.m (10%-20%). As a result, there exists a need for an improved lapping sensor which provides a more accurate measure of the recording element throat heights during the mechanical lapping process. Ideally, such a sensor would still be manufacturable during the same thin film photolithographic process steps used to fabricate the recording elements themselves.

Lapping sensor for thin film recording elements and method for manufacturing same


A method for the treatment of neurodegenerative diseases comprising administering to a patient in need of such treatment a therapeutically effective amount of a peptide compound selected from the group consisting of:. (i) vasoactive intestinal peptide (VIP); PA0 (ii) analogues of vasoactive intestinal peptide (VIP) in which one or more amino acids has been replaced, added or deleted without substantially altering the biological properties of the parent peptide; PA0 (iii) a conjugate being a peptide compound according to either of (i) and (ii) coupled to a lipophilic moiety; PA0 (iv) a physiologically active fragment of (i), (ii) and (iii); and PA0 (v) a functional derivative of any of (i), (ii), (iii) and (iv);. optionally in combination with a pharmaceutically acceptable carrier.

Neurodegenerative diseases in which neuronal cells degenerate bring about a deterioration of cognitive functions. A variety of diseases and neurological deficiencies may bring about the degeneration of neuronal cells among them Alzheimer's disease, Huntington disease or chorea, hypoxia or ischemia caused by stroke, cell death caused by epilepsy, amyotrophic lateral sclerosis, mental retardation etc., as well as neurodegenerative changes resulting from aging.
Vasoactive intestinal peptide (VIP) is a 28 amino acid regulatory peptide which exhibits neurotransmitter and hormonal roles. VIP has a discrete distribution in the central nervous system (CNS), with highest levels in the cerebral cortex, hypothalamus, amygdala and corpus striatum. Accumulated evidence suggest the involvement of VIP in a multitude of neuronal functions among them: changes in membrane potential, modulation of muscarinic excitation, promotion of survival of electrically blocked neurons.sup.(1), maintenance of neural integrity.sup.(2), development of neonatal behavior in rats.sup.(3), rescue from neural death caused by HIV envelope protein. A VIP-receptor antagonist caused spatial learning impairment in rats which was attenuated by co-treatment with VIP, indicating a possible role for VIP in the process of learning.sup.(4).
There is conflicting evidence concerning the role of VIP in dementia in general and in Alzheimer's disease in particular. A large body of evidence suggests no such involvement. Rosor et at found no changes in VIP in cerebral cortex of brains obtained from patients suffering from senile dementia of the Alzheimer's type as compared to controIs.sup.(5). Other investigators found no variance in VIP measurement between Alzheimer's patients and controls.sup.(6,7,8), and no correlation was found between the degree of dementia and the concentration of VIP in the cerebrospinal fluid.sup.(9).
In contrast, a study of immunoreactivity of VIP in Alzheimer's and control brains showed a significant reduction of VIP immunoreactivity in the cerebral cortex especially in the insular and angulate cortex of Alzheimer's patients.sup.(10). However, it has never been determined whether this reduction was the cause or rather the result of the Alzheimer's deterioration of the cerebral cortex.

Method for the treatment of neurodegenerative diseases by administering VIP, an analogue, fragment or a conjugate thereof

Ramot University Authority for Applied Research and Industrial Development Ltd.


A surface enhanced luminescence analyte nano pillar stage may include a substrate, an array of closable pillars extending from the substrate and a fluid supply connected to the array of pillars. The fluid supply is to at least partially replenish fluid amongst the pillars of the array that has evaporated to maintain a level of the fluid amongst the pillars of the array below tops of the pillars.

Nano pillars are sometimes used in surface enhanced luminescence procedures. With such procedures, the nano pillars are closed or bent towards one another to form plasmonic "hotspots". In many applications, capillary forces are utilized to close the nano pillars.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

Surface enhanced luminescence nano pillar stage

Hewlett-Packard Development Company, L.P.


A dispensing nozzle for a container with a long tapered nozzle body has a narrow tapered dispensing end and a wider base end. A passage for fluid runs from the base end to the dispensing end and through an outlet. The dispensing nozzle has a removable cap that fits over the dispensing nozzle when in the closed position which closes the dispensing nozzle's outlet with a penetrating plug located on the interior of the cap. The cap has a narrow closed end that has the penetrating plug on its interior side and the cap has a wider open end. The cap fits onto the nozzle in a tight fit when closed. The invention contemplates that the fluid in the container is strong glue, so that hardened glue makes removing the cap difficult. To solve this problem, the nozzle and the cap have two distinct sets of ramps that provide the initial separating force to twist the cap with respect to the nozzle in order to remove the cap easily and allow dispensation.

1. Field of the Invention
The present invention relates to a dispensing nozzle and cap. The invention also relates to an assembly comprising the nozzle or cap and to a container fitted with the nozzle and/or cap.
2. Brief Description of Related Technology
There have been provided many types of nozzles for dispensing a dispensable product. Caps which fit over the nozzle to close the nozzle off after use and for storage are also well known. The nozzles/caps may be employed in many end-use applications.
One problem which arises in certain instances is the removal of the cap from the nozzle. This occurs when the nozzle has been used to dispense product and product remains on the exterior of the nozzle when the dispensing action is complete. Replacement of the cap over the nozzle, often times then causes the cap also to be contaminated with the remaining product. This may in turn cause difficulty in subsequent removal of the cap from the nozzle. Product may for example cause the cap to be bonded to the nozzle and/or may otherwise interfere with the removal of the cap from the nozzle for example by fouling screw-threads etc.
Difficulty of removal of the cap from its position over-fitting the nozzle is undesirable, as a user of the product which is being dispensed, may find that they can no longer manually remove the cap from the nozzle, because the resistance to doing so by the product may be too great. If any tool is employed to assist a user in trying to remove a difficult-to-remove cap then the force applied to remove the cap can damage the nozzle and/or cap so that they no longer fit together in the required fashion. It is quite usual, in circumstances where a mechanical force is employed, to experience some form of material failure for example: shearing off the nozzle; breakage of the cap; or rupturing of the container for holding the product to be dispensed.
Attempts have been made to provide nozzle/cap arrangements which seek to minimise the circumstances in which material failure might occur, and to allow a user to remove the cap from its position over-fitting the nozzle with a minimum of force.
One known cap/nozzle assembly comprises a cap of the type having an elongate nozzle body having a base and a second dispensing end. A conduit defined in the nozzle body is provided for delivering product from the base to the dispensing end. The nozzle has three portions of different diameter. One portion of the nozzle is provided with external screw threads, which co-operate with internal reciprocal threads on the exterior of an over-fitting cap.
The over-fitting cap is of the type having a first closed end; a housing defining a second open end and with a rim about the open end. The cap is also provided with screwthreads, which co-operate with the external reciprocal threads on the exterior of the nozzle.
Both parts are typically made from very strong plastics material, so that they can withstand the quite substantial forces which may be applied, to try to remove the cap from its position over-fitting the nozzle. The screwthreads are arranged with a relatively low pitch so that the relative rotation of the cap and the nozzle is relatively easy for the user. The screwthreads are located at a position where they are spaced quite a distance from the dispensing end of the nozzle so that the risk of contamination with product is minimised. However even with such a construction the two parts become bonded and prove difficult to remove. Notwithstanding the use of stronger materials, material failure such as described above can occur in the event that relatively substantial mechanical force is applied.
Furthermore the costs of the materials which are used to make the nozzle/cap arrangement are substantial, given the need for strongly constructed components which is reflected in thicker walls etc. which in turn is achieved by utilising greater amounts of materials. In some earlier constructions a pin provided within the cap and arranged to penetrate the conduit of the nozzle was necessarily of metal construction. Another problem experienced with some prior art arrangements is that of spreading of the cap due to deformation of the cap due to forces applied to remove the cap from the nozzle. In such case the cap diameter misshapes spreading away from the nozzle.
It is thus desirable to provide a nozzle and cap arrangement which addresses the problem of difficulty in opening the cap when the arrangement is contaminated with product and also to reduce costs in the materials being employed, in particular by reducing the amounts of materials being employed, and also by reducing the assembly costs during manufacture.


Methods and systems are provided for implementing a distributed algorithm for beam-forming (e.g., MVDR beam-forming) using a message-passing algorithm. The message-passing algorithm provides for computations to be performed in a distributed manner across a network, rather than in a centralized processing center or “fusion center”. The message-passing algorithm may also function for any network topology, and may continue operations when various changes are made in the network (e.g., nodes appearing, nodes disappearing, etc.). Additionally, the message-passing algorithm may minimize the transmission power per iteration and, depending on the particular network, also may minimize the transmission power required for communication between network nodes.

Specific sound sources can be extracted from a set of microphone signals by means of beam-forming. To be able to deal with a wide range of scenarios, it is desirable to perform beam-forming using a subset of an unlimited number of microphones, and to organize these microphones by means of wireless communication.
To make such a system practical and scalable, the computations should be performed in a distributed manner across the network, rather than in a centralized processing center or "fusion center." One algorithmic approach performs distributed processing but requires that all the nodes in the network be able to communicate to each other. As a result, the approach is not scalable nor does it allow for implementation in an arbitrary topology. Such an approach is therefore not practical for large systems.

Distributed beamforming based on message passing


A breastfeeding assist timepiece includes a housing containing a first live time display and a second resettable static time display. A left/right side indicator is defined at a further location of said housing. In use, the static time display is continuously reset to a time of a most recently completed feeding, with the left/right side indicator further designating a left or right breast employed first in the most recent feeding and in order to more accurately predict the timing of a present or future feeding, as well as which breast to be initially employed in that feeding.

Timer devices are well known in the relevant art. A particular subset species of timers specifically deals with baby care timers, such as reminding iterative feeding and napping times.
The itzbeen baby timer teaches a portable device with up to four digital timers, such as which can correspond to changing, feeding, sleeping, and medication schedules. Of note, the itzbeen device includes a nursing reminder with a left/right side indicator.
A related disclosure teaching a breast feeding timer is described in Juve U.S. Pat. No. 4,972,391 and incorporates an electronic circuit for counting an elapsed time in minutes succeeding a previously initiated nursing session. The elapsed time is presented upon a visual display which also includes a left/right side breast sub-display for indicating the breast from which the baby was last fed. The timer also includes a reference clock, clock counter, alarm counter and three digit digital display including separate right/left sub-displays, and an audible alarm.
German reference DE 101 29 621 teaches a breast feeding watch with an analog face and within which is set twin digital dynamic displays, each being a chronograph dynamically displaying the duration of time since the last feeding from either a left or right side breast.
Reiner U.S. Pat. No. 5,691,932 teaches a care giver data collection and reminder system for providing a range of baby care information entry fields, among them including feeding times and left/right side breast indicator.
Additional references of note include Nomura U.S. Pat. No. 4,338,680, which teaches an earlier version of analog display watch with digital inset for displaying alarm time information as well as the dual timing event stopwatch of Rose U.S. Pat. No. 4,505,595.

Device incorporating both time keeping and static adjustment dials for determining feeding times and position


The present invention relates to a new process of synthesizing conductive polymers from monomers substituted with amine group. The process provides simple synthesizing steps for the conductive polymers without using other additives such as stabilizers or emulsifiers. The conductive polymers synthesized according to the present invention have highly enhanced solubility in common organic solvents and electrical conductivity compared to conventional conductive polymers. Therefore, the conductive polymers synthesized according to the present process can be utilized in applications that require high electrical conductivity, for example an electro-magnetic interference shield or a transparent electrode of thin film, as well as in specific applications such as various conductive films, fibers, polymer blends, battery electrodes or conductive etch mask layers.

1. Field of the Invention
The present invention relates to conductive polymers, and more particularly to conductive polymers which have highly enhanced solubility in organic solvents and electrical conductivity, and synthesizing process thereof.
2. Discussion of the Related Art
Conductive polymers have conjugated structures along double bonds present in the backbone thereof and has much enhanced electrical conductive properties compared to other organic materials because the conductive polymers form partial electrical charges along the conjugate structures and thereby having unlocalized electrons when the polymers are doped with dopants such as a protonic acid. Because the conductive polymers have both enhanced electrical, magnetic or optical properties comparable with conventional metals and satisfactory mechanical properties and processability as conventional polymers, they have been remarkably attracted in the filed of chemistry, physics, material engineering and industries.
The first developed conductive polymer is polyacetylene, which was developed by Shirakawa et al., however, polyacetylene is oxidized easily in the air. After polyacetylene was developed, Conductive polymers such as polyaniline, polypyrrole, and polythiophene have been developed.
The conductive polymers can be used in various applications according to their electrical conductivity. For example, the conductive polymers with electrical conductivity of 10−13˜10−7 (S/cm), 10−6˜10−2 (S/cm), and equal to and more than 100 (S/cm), respectively have been used as antistatic materials, static discharge materials, and electro-magnetic interference(EMI) shielding materials, battery electrodes, semiconductor and solar cells. Accordingly, the conductive polymers may be utilized in more various applications by improving their electrical conductivities.
Among intrinsically conducing polymers, polyaniline has been noticed in the relevant field since it is not only cheap and very stable compared to polypyrrole and polythiophene also doped easily by protonic acids.
The polyaniline (PANI) can be classified into the completely reduced from, leucoemeraldine, the intermediated oxidized form, emeraldine, and the fully oxidized form, pernigraniline, according to its oxidation state.
However, the conductive polymers synthesized through the conventional processes, especially the polyaniline as the completely reduced from, leucoemeraldine, the intermediated oxidized from, emeraldine salt, and the fully oxidized form, pernigraniline, have disadvantages that they cannot be made from melting process owing to their high boiling point and that they must experience complex processing steps since they have low solubility in solvents with high-boiling point or universal or compatible solvents such as meta-cresol.
In order to improve the problems of the conductive polymers as indicated above, copolymers such as aniline derivatives or graft copolymers have been synthesized by inducing various side chains into the benzene ring or amine group of the conductive polymers for improving solubility of the backbone of the conductive polymers. Alternatively, various dopants, or other organic materials, polymers or plasticizers are added into the conductive polymer for improving the processability and the electrical conductivity of the conductive polymers. However, those composites have lower electrical conductivity compared to the conductive polymers before reforming.
Polyaniline (PANI) can be synthesized either by electro-chemical charge transfer reaction which uses electro-chemical reaction or by chemical oxidation process that uses protonation through acid-base or redox reaction. However, it has been known that the chemical oxidation process is suitable for producing polyaniline in industrial scales.
Representative chemical oxidation process for synthesizing polyaniline has been reported to MacDiarmid et al., who synthesized polyaniline by polymerizing aniline monomers dissolved in hydrochloric acid with oxidizing agents such as ammonium persulfate in aqueous solution in the temperature of 1˜5° C., separating and washing the precipitates and then obtaining polyaniline (See A. G. MacDiarmid, J. C. Chiang, A. F. Richter, N. L. D. Somarisi, in L. Alcacer (ed.), Conducting Polymers, Special Applications, Reidel, Dordercht, 1987, p. 105). The MadDiarmid process have been utilized widely and regarded as a standard method for producing polyaniline.
The polyaniline of emeraldine base (EB) synthesized according to the MacDiarmid process has low molecular weight (intrinsic viscosity 0.8˜1.2 dl/g), but it is dissolved in 1-methyl-2-pyrrolidon (NMP). Also it has reported that emeraldine salt produced by doping the EB with 10-camphorsulfonic acid (ES-CSA) is dissolved a little in meta-cresol. The film made from that solution containing ES-CSA has at most electrical conductivity of about 100 S/cm, on the other hand, the film made from emeraldine salt doped with hydrochloric acid (ES-HCl) shows highly lower electrical conductivity of about 5 S/cm. However, it needs to be separating not dissolving portion from the dissolved portion in the MacDiarmid process. Especially, the polyaniline synthesized according to the MacDiarmid process has low molecular weight, broad molecular weight distribution, and inferior solubility to solvents or electrical conductivity resulted from side chain reactions to the backbone. Therefore, there remains a need of improving the micro-chemical structure or electrical conductivity of polyaniline synthesized according to the MacDiarmid process.
In order to improve the disadvantages and inferior processability of the polyaniline synthesized by MacDiarmid process, a lot of researches which use emulsion polymerization have been suggested. For example, U.S. Pat. No. 5,232,631 and No. 5,324,453 to Cao et al., which are incorporated herein by reference, disclose process for synthesizing polyaniline by dissolving aniline monomers and functionalized protonic acid in polar solvents such as water, mixing the solution with an organic solvent to prepare an emulsion, and then adding an oxidizing agent into the emulsion. Cao et al. reported that the emeraldine salt (ES) can be dissolved in nonpolar solvent such as xylene because emulsifier acts as a dopant, and therefore, it is reacted with the polyaniline to form composite. However, since Cao et al. uses functionalized protonic acids as emulsifier, it is difficult to control doping the emulsifier and the process requires commonly expensive material. Further, since the functionalized organic acid is hardly separated from polyaniline after polymerizing reaction, the conductive polymers may have only very limited uses and highly inferior electrical properties. For instance, the emeraldine salt, which synthesized according to Cao et al, doped with dodecyl benzene sulfonic acid (DBS) has a solubility of less than 0.5% and an electrical conductivity of only about 0.1 S/cm.
Kinlen of Monsanto produced polyaniline salt by preparing reverse emulsion system comprising an organic solvent such as 2-butoxyethanol soluble in water and an organic acid, which is not soluble in water but soluble in the organic solvent, as a hydrophobic emulsifier, mixing an aniline monomer and a radical initiator with the emulsion system and polymerizing the mixture to form polymer solution that has an organic layer, which contains polyaniline salt, separated from an aqueous layer containing the radical initiator and non-reacting compounds. (See U.S. Pat. No. 5,567,356; Kinlen, Macromolecules, 31, 1745 (1998), which are incorporated herein by reference). Kinlen reported that the polyaniline salt was soluble in nonpolar solvents of no less than 1% (w/w). However, it is difficult to synthesize polyaniline because the radical initiator in the aqueous layer is separated from the monomer in the organic layer and polyaniline synthesized according to Kinlen process has low electrical conductivity owing to difficulty of control doping process. For example, it was reported that polyaniline salt synthesized with dinonyl naphthalene sulfonic acid as a hydrophilic organic acid had an electrical conductivity of about 10−5 S/cm in case the salt is manufactured as pellets.
Harlev et al. synthesized polyaniline salt with the MacDiarmid process except using pyruvic acid instead of hydrochloric acid (See U.S. Pat. No. 5,618,469, which is incorporated herein by reference). It is possible to improve processability of polyaniline by using pyruvic acid because pyruvic acid functions as organic solvent as well as dopant. However, since pyruvic acid has lower acidity it is difficult to dope polyaniline by pyruvic acid. Accordingly, polyaniline doped with pyruvic acid has low electrical conductivity, and especially in case the polyaniline doped with pyruvic acid is used as a transparent electrode, it has very high apparent surface resistance as much as 20,000 Ω/square, which is very high electrical resistance for the transparent electrode.
Ho et al., produced polyaniline through emulsion system prepared by adding specific emulsifier into an organic mixture solvent comprising an aniline monomer and a protonic acid with stirring (See U.S. Pat. No. 6,030,551, which is incorporated herein by reference). According to Ho et al., both a radical initiator such as benzoyl peroxide and the polyaniline is dissolved in the same non-aqueous layer, and therefore, it is possible to synthesize polyaniline solution in situ without residual solids. However, since it is not easy to separate the non-aqueous layer from an aqueous layer, it is expected that polyaniline synthesized according to Ho process may not have high electrical conductivity.
U.S. Pat. No. 6,072,027 to Carey et al., which is incorporated herein by reference, discloses a producing method of polyaniline with highly enhanced polymerization yield, by using chlorate salt or hydrochloric acid combined with bi- or trivalent iron salt as a new oxidization initiator.
Palaniappan et al. disclose a process for the preparation of polyaniline salt by forming inverted emulsion system that comprises an aqueous layer and an organic layer using a surfactant and then polymerizing the inverted emulsion system at room temperature using a radical initiator such as benzoyl peroxide dissolved in the organic layer (See U.S. Patent publication No. 2002-00062005, U.S. Pat. Nos. 6,586,565 and 6,630,567, which are incorporated herein by reference). However, polyaniline film prepared from Palaniappan process has very low electrical conductivity, for example about 0.1 S/cm, and may be only used in much limited applications since it is impossible to raise molecular weight of polyaniline.
In addition to emulsion polymerization as above, polyaniline synthesis processes through a dispersion polymerization, in which monomers such as aniline is fully dissolved in reacting solvent while synthesized polymers are not dissolved in the solvent, have been reported. For example, Armes et al. reported the polymerization process which comprises stabilizing sterically the conductive polymer by designing particular stabilizer and then particularizing the conductive polymer (See Armes et al., handbook of Conducting Polymers, Elsenbaumer ed. M. Dekker, New York, 1996, Vol. 1, p. 423). In this dispersion polymerization, since most of the stabilizer covers with the polyaniline, the polyaniline in aqueous solution can be prepared. However, the synthesized polyaniline has a particle size of about 60˜300 nm, which is affected by the stabilizer, and has low electrical conductivity, which defines its application.
Further, there have been reported that polyaniline is synthesized in aqueous solution containing organic solvents. Geng et al. prepared polyaniline film, which has electrical conductivity of about 10 S/cm, through synthesizing polyaniline with organic solvents such as ethanol, THF, and acetone (See Geng et al., Synth. Metals. 96, 1 (1998)). However, since it needs very long polymerization reaction time in Geng process, a probability of side reaction is raised.
According to Beadel et al., the polyaniline produced by the standard synthesizing method disclosed in MacDiarmid as described above has higher electrical conductivity as it has higher molecular weight. Accordingly, the monomer needs to be reacted or polymerized at lower temperature in order to enhance molecular weight of the polymer (See Beadel et al., Synth. Met. 95, 29˜45, 1998). For lowering reacting temperature, when aniline monomer is polymerized in homogeneous aqueous solution system, metallic salts such as LiCl, CaF2 and the likes are usually added to the system in order to prevent the system from freezing. However, mixing those metallic salts with the solution system causes the reaction to being slow, that is to say, at least 48 hours to complete the polymerizing reaction, and therefore, it is difficult to control the polymerization reaction. Also, as lowering the reaction temperature, the synthesized polyaniline has an increased molecular weight as well as molecular weight distribution (polydispersity of equal to or more than 2.5).
Also, there form side chains as the aniline monomer is added into a quinonediimine group in intermediate chains. Accordingly, FeCl2 as an oxidizing agent is added during polymerization reaction in order to inhibit formations of the side chains in polyaniline, or the polyaniline is eluted with organic solvents for removing side products such as oligomers which quit synthesis during the polymerization reaction. Besides, since the monomers are added into the polyaniline on the ortho-positions as much as the para-positions of the benzene ring in the polyaniline backbone in case of emulsion polymerization or interfacial polymerization, such synthesized polyaniline has much side chains, which cause the polyaniline to have lower electrical conductivity and solubility.
According to Thyssen et al., there is a probability of about 10% of the ortho coupling, which induces side chains in the backbone of the polymers, when the aniline monomers are polymerized by using electro-chemical process (See Thyssen et al., Synth. Met. 29, E357˜E362, 1989). Such polymers synthesized by ortho-coupling has lower hydraulic dimensions, which results in decreased intrinsic viscosity, compared to polymers synthesized by para-coupling, i.e. polymers without side chains. In other words, the polymers synthesized by ortho-coupling has much side chains and has more molecular weights even though they have low intrinsic viscosity of equal to or less than 1.2 dl/g. Accordingly, the polymers synthesized by ortho-coupling has inferior processability without improving the electrical conductivity.
Moreover, Huang et al. produced polyaniline of nano-fiber form by preparing a system which comprises an organic layer and an aqueous layer immiscible with the organic layer, dissolving an aniline monomer in the organic layer, and an initiator and an organic acid in the aqueous layer, and polymerizing the monomer in the interface (See Huang et al., J. Am. Soc. 125, 314 (2003)).
Min of Dupont Technology reported that conductive polymer with high yield could be obtained by increasing level of LiCl or NaCl as additive in the MadDiarmid process, as described above, up to 5-10 M at 0° C. for 3 hours (See G. Min, Synth. Met., 119, 273, (2001)).
In addition to the patents and references described above, many researches were reported for improving physical or chemical properties, for example electrical conductivity of the conductive polymers (Organic Conductive molecules and Polymers, Vol. I-IV, Ed. By H. S, Nalwa, John Wiley & Sons, New York, 1997; Handbook of Conducting Polymers Vol. I, II, Ed. By Skotheim et al., Marcel Dekker, New York, 1998; Conductive Polymers, P. Chandrssekhar, Kluwer Acade. Pub. Boston, 1999; Conductive Electroactive Polymers by G. G. Wallace, G. M. Spinks, L. A. P. Kane-Maquire, P. T. Teasdale, 2nd ed. CRC Press, New York, 2003).
However, the polyaniline producing processes disclosed to date make use of introducing substituents into monomers or mixing the monomers with immense amount of additives such as stabilizer or emulsifier, and therefore, it is difficult to obtain pure polyaniline. Also, because polyaniline according to conventional processes has synthesized by ortho-coupling as much as para-coupling and frequently forms side chains by side reactions, such polyaniline does not have high electrical conductivity, which limits its applications.
Also, polypyrrole has been synthesized mainly by electro-chemical synthetic process. In case of synthesizing polypyrrole by the electro-chemical process, unlike synthesizing polyaniline, acids are not added during polymerization, which makes the reaction simplify. However, when polypyrrole is synthesized according to the chemical process, side reactions such as inter-chain crosslink or side chain addition to the backbone of polypyrrole frequently happened, which causes synthesized polypyrrole to not dissolving in common solvents and therefore deteriorates processability. In case of synthesizing polypyrrole by electrical process, solvents or counter ions of conductive plate have highly affects on physical properties of polypyrrole.
Lee et al. prepared of conductive polypyrrole powder by reacting pyrrole monomers at 0° C. for 40 hours using chloroform and dodecyl benzene sulfonic acid (DBSA) of the same molar equivalents of chloroform (See J. Y. Lee, D. Y. Kim, C. Y. Kim, Synth. Met. 74, 103 (1995)). DBSA adopted by Lee et al. acts as both dopant and surfactant. However, polypyrrole film sample synthesized by Lee et al. has very low electrical conductivity of about 5 S/cm.
Besides, chemical process for synthesizing polypyrrole in organic solvents such as CHCl3, THF, or CH3N2O has been tried in order to produce polypyrrole being able to dissolve in the organic solvents. However, such synthesized polypyrrole did not have electrical conductivity at all.
Ames et al. reported a process for preparing stable colloidal polypyrrole by using poly-vinylalcohol, poly-ethyleneoxide, or poly-vinylpyridine as a steric stabilizer dissolved in water (See Armes et al., Handbook of Conducting Polymers Elsenbaumer ed. M. Dekker, New York, 1996, Vol. 1, p. 423). However, since polypyrrole powders are surrounded by a lot of stabilizers, like polyaniline, and therefore polypyrrole has a very low electrical conductivity.
Accordingly, it may enhance electrical conductivity of polypyrrole by linking pyrrole monomers on 2, 5 positions between pyrrole ring and sustaining linearity thereof. As mentioned above, pyrrole may be soluble in much solvents compared to aniline, however, it is very difficult to dissolve oxidizing agent and pyrrole monomer in the same solvent.
The synthetic conductive polymers, especially polyaniline has much lower real electrical conductivity than theoretically calculated electrical conductivity, about 105˜106 S/cm (Kohlamn et al., Phys. Rev. Lett. 78(20), 3915, 1997), because they does not have fully linear form and form completely orders such as crystalline structure per se. Since such polymers with lower electrical conductivity cannot be utilized as transparent plastic electrode or EMI shielding materials, there still remain needs of development of polyaniline having much improved electrical conductivity in the related field.

Conductive polymers having highly enhanced solubility in organic solvent and electrical conductivity and synthesizing process thereof


Apparatus and method for conditioning batteries such as those of the nickel-cadmium type for which deep discharge prior to recharge is desirable. Mechanical programming plates having different patterns of apertures for batteries of different characteristics are provided. When a battery is to be conditioned, one of the programming plates having an aperture pattern representing the characteristics of that battery is attached to the battery and the combined battery/programming plate is positioned on the battery conditioner. A surface of the conditioner contains programming pins that sense the aperture pattern on the programming plate and automatically program the discharging/charging circuits to provide a discharge/charge sequence that is tailored to the particular characteristics of the battery being conditioned.

Various types of batteries require differing profiles of battery charging/discharging if they are to provide dependable service and optimum service life. For example, lead-acid batteries commonly employed in automobiles retain optimal service life and characteristics best when maintained essentially fully charged. Such batteries suffer degradation and service life characteristics when they are subjected to deep discharge. Conversely, other types of rechargeable batteries tend to maintain optimal characteristics only if during each charge/discharge cycle, they are deeply discharged. Examples of such batteries are those of the popular nickel cadmium variety.
Nickel cadmium batteries, if recharged after only partial discharge, tend to experience deterioration in their total charging capability. Thus, after several such cycles, a nickel cadmium battery will typically retain substantially less than its originally rated number of ampere hours, a result that is generally considered to be disadvantageous and to be avoided when practicable. However, it has been the practice in the past for battery users to oftentimes substitute a fresh battery for one which has had some use prior to full discharge so as to avoid experiencing complete loss of battery power during an extended period of use, thereby introducing the danger of adversely impacting subsequent battery characteristics of the only partially discharged battery.
To overcome the potentially deleterious results of repeatedly recharging batteries such as nickel cadmium batteries after only partial discharge, prior art proposals include the intentional deep discharge of any charge remaining in the battery as part of the recharging process. Illustrative of such a procedure are the proposals of U.S. Pat. Nos. 4,179,648, granted to Edward Samsioe on Dec. 18, 1979 and 4,302,714 to Sheldon Yefsky on Nov. 24, 1981.
Although these proposals were directed generally to the solution of the aforementioned problems, there still existed the matter of setting discharge and recharging conditions to tailor them to optimum levels for any of a variety of battery sizes and current ratings. One proposal includes the tailored conditioning of the equipment parameters to reflect the specific characteristics of a battery by providing for the manual setting of dip switches. However, such have been subject to the undesirable consequences of setting errors, switch malfunction, or loss of instructions for switch setting.


Provided is a barbecue apparatus for preventing flare-ups and improving temperature distribution and heat retention when cooking on a barbecue. The apparatus comprises at least one plate that is movable between a first position lying atop a respective side of at least one burner tent and a second position withdrawn from the respective side of the at least one burner tent. Further provided are a barbecue comprising said apparatus and a method of preventing flare-ups and improving temperature distribution and heat retention when cooking on a barbecue by moving at least one plate between a first position lying atop a respective side of at least one burner tent and a second position withdrawn from the respective side of the at least one burner tent.

Three well known problems when cooking with a gas barbecue are: 1) flare ups while cooking; 2) uneven cooking temperature, also referred to as "hot spots" or "cold spots" in a gas barbeque; and 3) a rapid loss in cooking temperature when opening the barbecue lid to check on or turn food being cooked.
Previous solutions attempting to address the first one or two of the above issues often employ a mechanism for rotating the grill of a round barbecue so that the food on different areas of the grill remain in motion and are exposed to the different parts of the overall cooking area.
Another proposed solution has been to instead rotate the burner of a gas grill so that the source of flame moves around the cooking area to evenly distribute heat and avoid scorching by prolonged exposure of any given piece of food to a flare up of the flame.
Yet another proposal suggests supporting charcoal or wood in a rotating tray situated below the grill but elevated above the stationary bottom of the barbecue.
When cooking with skewers, another solution has been to provide a mechanism that holds multiple radially-oriented skewers at a central point over the barbecue grill and rotates to revolve the skewers around the grill.
However, it is clear that these 'rotational' solutions rely on mechanisms that are only suitable for barbecues of round circumference. Accordingly, there remains a need for solutions that address one or more of the above listed problems when cooking with a rectangular barbecue grill.

Barbecue, apparatus, and method for improved temperature distribution, heat retention, and flare-up prevention


A sampled amplitude read channel for reading information stored on a magnetic medium by detecting digital data from a sequence of discrete time interpolated sample values, the interpolated sample values generated by interpolating a sequence of discrete time channel sample values generated by sampling pulses in an analog read signal from a magnetic read head positioned over the magnetic medium. A write VFO generates a write clock for writing digital data to the magnetic medium at a predetermined baud rate for a selected zone, and upon read back, the write VFO generates a sampling clock at a frequency slightly higher than the write frequency. A sampling device samples the analog read signal at the sampling clock rate to generate a sequence of discrete time channel samples that are not synchronized to the baud rate. The channel samples are equalized by a discrete time equalizing filter according to a predetermined partial response (PR4, EPR4, EEPR4, etc.). An interpolating timing recovery circuit, responsive to the equalized channel samples, computes an interpolation interval .tau. and, in response thereto, generates interpolated sample values substantially synchronized to the baud rate. The timing recovery circuit also generates a data clock for clocking a discrete time sequence detector for detecting the digital data from the interpolated sample values.

In magnetic storage systems for computers, digital data serves to modulate the current in a read/write head coil so that a sequence of corresponding magnetic flux transitions are written onto a magnetic medium in concentric tracks at a predetermined baud rate. When reading this recorded data, the read/write head again passes over the magnetic medium and transduces the magnetic transitions into pulses in an analog signal that alternate in polarity. These pulses are then decoded by read channel circuitry to reproduce the digital data.
Decoding the pulses into a digital sequence can be performed by a simple peak detector in a conventional analog read channel or, as in more recent designs, by a discrete time sequence detector in a sampled amplitude read channel. Discrete time sequence detectors are preferred over simple analog pulse detectors because they compensate for intersymbol interference (ISI) and are less susceptible to noise. As a result, discrete time sequence detectors increase the capacity and reliability of the storage system.
There are several well known discrete time sequence detection methods including discrete time pulse detection (DPD), partial response (PR) with Viterbi detection, maximum likelihood sequence detection (MLSD), decision-feedback equalization (DFE), enhanced decision-feedback equalization (EDFE), and fixed-delay tree-search with decision-feedback (FDTS/DF).
In conventional peak detection schemes, analog circuitry, responsive to threshold crossing or derivative information, detects peaks in the continuous time analog signal generated by the read head. The analog read signal is "segmented" into bit cell periods and interpreted during these segments of time. The presence of a peak during the bit cell period is detected as a "1" bit, whereas the absence of a peak is detected as a "0" bit. The most common errors in detection occur when the bit cells are not correctly aligned with the analog pulse data. Timing recovery, then, adjusts the bit cell periods so that the peaks occur in the center of the bit cells on average in order to minimize detection errors. Since timing information is derived only when peaks are detected, the input data stream is normally run length limited (RLL) to limit the number of consecutive "0" bits.
As the pulses are packed closer together on the concentric data tracks in the effort to increase data density, detection errors can also occur due to intersymbol interference, a distortion in the read signal caused by closely spaced overlapping pulses. This interference can cause a peak to shift out of its bit cell, or its magnitude to decrease, resulting in a detection error. The ISI effect is reduced by decreasing the data density or by employing an encoding scheme to ensure that a minimum number of "0" bits occur between "1" bits. For example, a (d,k) run length limited (RLL) code constrains to d the minimum number of "0" bits between "1" bits, and to k the maximum number of consecutive "0" bits. A typical RLL (1,7) 2/3 rate code encodes 8 bit data words into 12 bit codewords to satisfy the (1,7) constraint.
Sampled amplitude detection, such as partial response (PR) with Viterbi detection, allows for increased data density by compensating for intersymbol interference and increasing channel noise immunity. Unlike conventional peak detection systems, sampled amplitude recording detects digital data by interpreting, at discrete time instances, the actual value of the pulse data. A sampling device samples the analog read signal at the baud rate (code bit rate) and an equalizing filter equalizes the sample values according to a desired partial response. A discrete time sequence detector, such as a Viterbi detector, interprets the equalized sample values in context to determine a most likely sequence for the data (i.e., maximum likelihood sequence detection MLSD). In this manner, the effect of ISI and channel noise can be taken into account during the detection process, thereby decreasing the probability of a detection error. This increases the effective signal to noise ratio and, for a given (d,k) constraint, allows for significantly higher data density as compared to conventional analog peak detection read channels.
The application of sampled amplitude techniques to digital communication channels is well documented. See Y. Kabal and S. Pasupathy, "Partial Response Signaling", IEEE Trans. Commun. Tech., Vol. COM-23, pp. 921-934, Sept. 1975; and Edward A. Lee and David G. Messerschmitt, "Digital Communication", Kluwer Academic Publishers, Boston, 1990; and G. D. Forney, Jr., "The Viterbi Algorithm", Proc. IEEE, Vol. 61, pp. 268-278, March 1973.
Applying sampled amplitude techniques to magnetic storage systems is also well documented. See Roy D. Cideciyan, Francois Dolivo, Walter Hirt, and Wolfgang Schott, "A PRML System for Digital Magnetic Recording", IEEE Journal on Selected Areas in Communications, Vol. 10 No. 1, January 1992, pp. 38-56; and Wood et al, "Viterbi Detection of Class IV Partial Response on a Magnetic Recording Channel", IEEE Trans. Commun., Vol. Com-34, No. 5, pp. 454-461, May 1986; and Coker Et al, "Implementation of PRML in a Rigid Disk Drive", IEEE Trans. on Magnetics, Vol. 27, No. 6, Nov. 1991; and Carley et al, "Adaptive Continous-Time Equalization Followed By FDTS/DF Sequence Detection", Digest of The Magnetic Recording Conference, Aug. 15-17, 1994, pp. C3; and Moon et al, "Constrained-Complexity Equalizer Design for Fixed Delay Tree Search with Decision Feedback", IEEE Trans. on Magnetics, Vol. 30, No. 5, Sept. 1994; and Abbott et al, "Timing Recovery For Adaptive Decision Feedback Equalization of The magnetic Storage Channel", Globecom'90 IEEE Global Telecommunications Conference 1990, San Diego, Calif., Nov. 1990, pp. 1794-1799; and Abbott et al, "Performance of Digital Magnetic Recording with actualization and Offtrack Interference", IEEE Transactions on Magnetics, Vol. 27, No. 1, Jan. 1991; and Cioffi et al, "Adaptive Equalization in Magnetic-Disk Storage Channels", IEEE Communication Magazine, Feb. 1990; and Roger Wood, "Enhanced Decision Feedback Equalization", Intermag'90.
Similar to conventional peak detection systems, sampled amplitude detection requires timing recovery in order to correctly extract the digital sequence. Rather than process the continuous signal to align peaks to the center of bit cell periods as in peak detection systems, sampled amplitude systems synchronize the pulse samples to the baud rate. In prior art sampled amplitude read channels, timing recovery synchronizes a sampling clock by minimizing an error between the signal sample values and estimated sample values. A pulse detector or slicer determines the estimated sample values from the read signal samples. Even in the presence of ISI the sample values can be estimated and, together with the signal sample values, used to synchronize the sampling of the analog pulses in a decision-directed feedback system.
A phase-locked-loop (PLL) normally implements the decision-directed feedback system to control timing recovery in sampled amplitude read channels. A phase detector generates a phase error based on the difference between the estimated samples and the read signal samples. A loop filter filters the phase error, and the filtered phase error operates to synchronize the channel samples to the baud rate.
In prior art timing recovery methods, the phase error adjusts the frequency of a sampling clock which is typically the output of a variable frequency oscillator (VFO) . The output of the VFO controls a sampling device, such as an analog-to-digital (A/D) converter, to synchronize the pulse samples to the baud rate.
Also in prior art timing recovery methods, it is helpful to first lock the PLL to a reference or nominal sampling frequency so that the desired sampling frequency, with respect to the analog pulses representing the digital data, can be acquired and tracked more efficiently. The nominal sampling frequency is the baud rate, the rate that data was written onto the medium. Therefore, one method to lock-to-reference is to generate a sinusoidal signal relative to the output of a write VFO (write clock) and inject this signal into the PLL. Once locked to the reference frequency, the PLL input switches from the write clock to the signal from the read head in order to synchronize the sampling of the waveform in response to a sinusoidal acquisition preamble recorded on the medium.
The acquisition and tracking modes for timing recovery are related to the data format of the magnetic disk. FIG. 2A shows a magnetic disk comprising a plurality of concentric data tracks 13 wherein each data track 13 is comprised of a plurality of sectors 15. Servo data in the form of wedges 17 are embedded into the sectors 15 and used to control and verify the track and sector position of the read/write head. FIG. 2B shows the format of a sector 15 comprising an acquisition preamble 68, a sync mark 70, and user data 72. The acquisition preamble is a predetermined sequence that allows timing recovery to acquire the desired sampling phase and frequency before reading the user data. After acquisition, the PLL switches to a tracking mode in order to track the desired sampling phase and frequency with respect to the analog pulses representing the user data. The sync mark signals the beginning of the user data. As illustrated in FIG. 2B, a short acquisition preamble is desirable to allow more storage area for user data.
Zoned recording is a technique known in the art for increasing the storage density by recording the user data at different rates in predefined zones between the inner diameter and outer diameter tracks. The data rate can be increased at the outer diameter tracks due to the increase in circumferential recording area and the decrease in intersymbol interference. This allows more data to be stored in the outer diameter tracks as is illustrated in FIG. 2A where the disk is partitioned into an outer zone 11 comprising fourteen data sectors per track, and an inner zone 27 comprising seven data sectors per track. In practice, the disk may actually be partitioned into several zones at varying data rates.
Prior techniques are known for acquiring and tracking the sampling frequency/phase based on the phase error computed from the actual signal samples and estimated signal samples obtained from symbol-by-symbol decisions. See "Timing Recovery in Digital Synchronous Receivers" by K. H. Mueller and M. Muller, IEEE Transactions on Communications, vol. Com-24 (1976), pp. 516-531. Co-pending United States patent application Ser. No. 08/313,491 entitled "Improved Timing Recovery for Synchronous Partial Response Recording" discloses an improvement to the Mueller and Muller stochastic gradient method. In this method of timing recovery a slicer, commonly employed in a d=0 PR4 partial response recording channel, estimates the sample values by comparing the signal sample values to predetermined thresholds. A stochastic gradient circuit, which minimizes the mean squared error between the signal sample values and the estimated sample values, generates the phase error to control the frequency of the sampling VFO.
U.S. Pat. No. 5,359,631 entitled "Timing Recovery Circuit for Synchronous Waveform Sampling" discloses yet another method for timing recovery in a sampled amplitude read channel. In this method a pulse detector, commonly employed in a d=1 EPR4 or EEPR4 partial response recording channel, operates to determine the estimated sample values. Again, a stochastic gradient circuit uses the estimated sample values, together with the signal sample values, to generate the phase error for adjusting the sampling clock in the decision-directed feedback system.
The timing recovery loop filter controls the dynamics of the decision-directed feedback system. Accordingly, the loop filter coefficients are adjusted to achieve a desired transient response and tracking quality. For good tracking quality, the loop bandwidth should be narrow so that phase noise and gain variance is attenuated. During acquisition, the loop bandwidth should be as wide as possible without being unstable to achieve a fast transient response. A fast transient response results in a shorter acquisition time which minimizes the necessary length of the acquisition preamble.
Several problems have been identified with timing recovery methods that synchronize sampling of the pulses using a variable frequency oscillator in a PLL. For instance, the slight difference in operating frequencies between the write VFO and the sampling VFO results in cross-talk that degrades the performance of timing recovery. Further, synchronous detection of embedded servo data requires an additional servo VFO to generate the center operating frequency of the sampling VFO when reading the servo data (see the above referenced U.S. patent entitled "Samples Amplitude Read Channel Employing a User Data Frequency Synthesizer and a Servo Data Frequency Synthesizer"). Yet another problem associated with conventional PLL timing recovery are the delays inherent in the sampling device and discrete time equalizing filter which cause the timing loop to be less stable. Thus, latency considerations can increase the cost and complexity of the sampling device and reduce the effectiveness of the equalizing filter. A more complex discrete time equalizing filter could equalize the samples before the timing loop, but this would require reconstruction at the filter's output from discrete-time back to continuous-time for processing by the sampling PLL.
There is, there-ore, a need for a new timing recovery technique for sampled amplitude recording that does not exhibit the cross talk phenomena associated with a write VFO frequency being very near a sampling VFO frequency. A further object is to avoid using a separate servo VFO for reading embedded servo data. Yet another object is to remove the sampling device and discrete time equalizing filter, and their associated latencies, from the timing recovery loop.

Sampled amplitude read channel employing interpolated timing recovery


A developing cartridge includes: a housing having first and second sidewalls through which respective end portions of a developing roller shaft are rotatably inserted; a developing gear, which is arranged outside of the first sidewall, and which is fixed to the end portion of the developing roller shaft; a transmission gear, which is arranged outside of the first sidewall, and which transmits driving force to the developing gear; a first cover member, which is attached to the first sidewall, and which covers the transmission gear; and a second cover member, which is attached to the first sidewall, and which covers the developing gear from an outer side in the axis line direction. The second cover member is formed separately from the first cover member and is arranged side by side with the first cover member outside of the first sidewall.

In an image forming apparatus such as a laser printer, there has been proposed a process cartridge that is detachably mounted to a main body of the apparatus.
The process cartridge includes a drum cartridge having a photosensitive drum and a developing cartridge that is detachably mounted to the drum cartridge and that has a developing roller.
A shaft of the developing roller (developing roller shaft) is rotatably supported by a developing frame that forms a housing for the developing cartridge. In addition, both end portions of the developing roller shaft protrude outwardly from the developing frame. A developing roller driving gear is attached to a part, of one end portion of the developing roller shaft, which protrudes from the developing frame.
When the developing cartridge is mounted to the drum cartridge and a circumferential surface of the developing roller contacts a circumferential surface of the photosensitive drum, the developing roller is rotated via the developing roller shaft when driving force is input to the developing roller driving gear. Thereby, developer is supplied from the circumferential surface of the developing roller to the circumferential surface of the photosensitive drum.

Developing cartridge and process cartridge for stably rotating developing roller


Disclosed is a liquid crystal display (LCD) backlight inverter. The LCD backlight inverter includes a lamp open detection unit outputting a first open detection voltage for a preset time period when it is determined that a predetermined lamp is open, based on a current voltage corresponding to the current of the predetermined lamp of a plurality of lamps, a first open determination unit outputting an open detection signal when the first open detection voltage is input, a second open determination unit outputting a protection signal when it is determined that all of the plurality of lamps are open based on detection voltages of the plurality of lamps, a temporary protection determination unit outputting a frequency change signal when both the open detection signal and the protection signal are input, and an operating frequency control unit changing an operating frequency to a preset protective frequency according to the frequency change.

1. Field of the Invention
The present invention relates to an inverter for driving lamps used for a backlight unit of a liquid crystal display (LCD), and more particularly, to an LCD backlight inverter, which can perform a protection operation by monitoring the state where all lamps are separated from their respective lamp connectors (hereinafter, also referred to as "All Lamp Connectors Open"), thereby preventing damage to internal components and circuits, including the lamps.
2. Description of the Related Art
In general, liquid crystal displays (LCDs) include backlights. The backlights may illuminate the LCD from the back of a display panel, which is unable to emit light by itself. Cold cathode fluorescent lamps (CCFLs) have been in common use in backlights for large LCDs, and require the use of an inverter for the operation thereof.
Maintaining even LCD lighting is a critical factor in the driving of the backlight lamps. To this end, the inverter employs a circuit that feeds back the current of the lamp in order to achieve constant lamp current. In addition, the inverter also includes an over-voltage protection circuit that serves to protect the lamps and the inverter circuit when excessive voltage is applied thereto.
The function as a protective circuit is very important for the inverter that drives the LCD backlight unit. Particularly, protecting devices upon the detection of an open lamp is one of the main functions of an inverter that drives multiple lamps.
The related art LCD backlight inverter employs a configuration that detects operating voltages of opposite phases being applied to a plurality of lamps. Thus, the inverter detects the opening, that is, the separation of some of a plurality of lamps by detecting the voltage resulting from unbalanced operating voltages occurring when some of the plurality of lamps are open, thereby performing a protective operation.
However, the related art LCD backlight inverter fails to recognize the state where all of the lamps are open (i.e., All Lamp Connectors Open) because unbalanced operating voltages are not generated in this state. For this reason, while no protective operation is enabled, the inverter performs a control operation to increase the operating current, which is currently at a low level due to the state of All Lamp Connectors Open. Consequently, the operating voltage is applied with a low switching frequency, damaging internal components and circuits, including the lamps.


A product is provided having a biobased component where the biobased component includes recycle polyester resin and the recycle polyester resin includes polyethylene terephthalate, polybutylene, or polypropylene terephthalate. The biobased component includes a polyester resin where the polyester resin is the co-reaction product of an aliphatic polyester having renewable components and a recycle polyester resin. Included is a composition having a filler and a polymeric binder. The filler includes inorganic biobased filler or recycle thermoset resin based filler.

Vinyl flooring is a major category of product for residential and commercial construction. Polyvinyl chloride (PVC) is the major polymeric material that functions as binder and imparts desired physical properties of vinyl flooring. Vinyl flooring product structures may include single layer products such as vinyl composition tile (VCT) and sheet and tile structures containing more than one layer. In some products, a high performance coating is utilized on the surface of the structure comprising PVC to impart improved scratch resistance.
Most layers of vinyl flooring products also include a plasticizer material to soften and allow processing of the PVC resin. Some liquid polyesters have found limited utility as plasticizers for PVC resins. Plasticizers contribute little to the strength properties of the final PVC layer after processing.
Typically, low molecular weight, liquid esters of aromatic acids such as phthalates and benzoates are utilized as plasticizers in flooring compositions. These plasticizers have enough volatility to be considered Volatile Organic Components in some clean air environments. The phthalate esters in particular are also suspect from an environmental/health perspective due to their possible biological activity.
One high volume, commercial vinyl tile product, VCT, typically comprises plasticizer and a blend of PVC homo-polymer and PVC co-polymer, e.g. vinyl acetate, as binders in the composition. The vinyl acetate co-polymer allows the composition to be melt when mixed in the low intensity mixers typically used in VCT manufacturing. The PVC compositions are typically heated to less than about 150° C. in tile processes utilizing such equipment. Another issue is that the vinyl acetate PVC co-polymer is currently in tight supply.
Recently, the US Green Building Council has established the LEED (Leadership in Energy and Environmental Design) system for scoring points for new commercial construction (Table 1). Under the LEED system, flooring can be used to obtain points if it contains 10% by weight of or more of post-industrial recycle material.
TABLE 1LEED System For New Commercial ConstructionRatingRatingSystemLEED-NC Version 2.1SystemLEED-EB Version 2.0MR Credit5% wt = (post-MR Credit10% (Post-4.1consumer + ½ post-2.1Consumer materials),1 Pointindustrial)1 PointorMR Credit10% wt = (post-20% (Post-4.2consumer + ½ post-Industrial materials)1 Pointindustrial)MR Credit5% wt = (rapidlyMR Credit50% (Rapidly6renewable building2.5renewable materials)1 Pointmaterials and products)1 Point
NC: New Construction; EB: Existing Building; Minimum % wt for each point. The % for both NC and EB is weight percent. For NC 1 point is granted for at least 5% wt of the total of post-consumer and ½ post-industrial. A second point is granted for at least 10% wt of the total of post-consumer and ½ post-industrial. An additional point is granted for at least 5% wt of rapidly renewable building materials and products. For EB 1 point is granted for at least 10% wt post-consumer materials. A second point is granted for at least 20% wt of post-industrial materials. An additional point is granted for at least 50% wt of rapidly renewable materials.
There has been renewed market interest in giving preference to "greener" flooring products based upon this LEED System. The use of renewable materials is of high interest.
There remains a need to develop "greener" flooring products based upon existing product structures/processes, and available recycle or renewable materials. There also is a need to find a binder system for vinyl flooring products that eliminates low molecular weight plasticizers and the need for vinyl acetate co-polymers of PVC in some vinyl tile manufacturing processes.
A product having a biobased component, where the biobased component includes recycle polyester resin would be desirable in the art.


A routing method of a semiconductor device includes steps (a) to (c). The step (a) checks a relation between a first interconnection pattern to be routed and a second interconnection pattern to be routed, wherein a line width of the second interconnection pattern is thicker than that of the first interconnection pattern. The step (b) refers to a routing rule of a design rule corresponding to a connection between the first interconnection pattern and the second interconnection pattern, when the first interconnection pattern and the second interconnection pattern would be routed in a same layer and connected each other. The step (c) routes the first interconnection pattern and the second interconnection such that the first interconnection is not bent in an area defined based on the routing rule.

1. Field of the Invention
The present invention relates to a semiconductor device, a routing method and manufacturing method of a semiconductor device. More particularly, the present invention relates to a semiconductor device in which interconnections can be routed properly, a routing method and manufacturing method of a semiconductor device which can route interconnections of the semiconductor device properly.
2. Description of the Related Art
In the layout design of a large scale integrated circuit (LSI), a placement and routing system is known, which automatically places logic cells and logic blocks (hereinafter referred to as logic cells/blocks) and routes interconnections (for example, Japanese Patent 3390393). The placement and routing system is exemplified in a CAD (Computer Aided Design) system. The placement and routing operation for using the placement and routing system is carried out, for example, as follows. At first, it reads the data with regard to the circuit diagram of a LSI of a design target, the data of logic cells/blocks prepared in a library, and the data with regard to a design rule. Next, it places the logic cells/blocks, based on the respective read data. Then, it routes interconnections among the placed logic cells/blocks based on the respective read data. After that, it verifies whether or not there is any trouble in the placement and routing, and carries out the re-placement and the re-routing if necessary. Finally, it generates the artwork data with regard to the routing of the entire chip corresponding to patterns in respective layers constituting the LSI based on the data of the placement and routing system.
Those, which are automatically placed and routed, are exemplified in followings. Those are: a thin interconnection, a thick interconnection and a macro (logic cells/blocks). The thin interconnection is thin in line width and exemplified in a signal interconnection. The thick interconnection is thicker in line width than the thin interconnection and exemplified in a power supply interconnection and a ground interconnection. The macro (logic cells/blocks) is exemplified in a memory. Here, a case of connecting the thin interconnection and a thick width figure is explained as an example. The thick width figure has a thick width as compared with the thin interconnection such as the macro and the thick interconnection.
FIG. 1 is an example of a layout view showing the connection between the thin interconnection and the thick width figure in the conventional placement and routing. Along grid lines 121 in an X-direction and grid lines 122 in a Y-direction, an interconnection A 111 and an interconnection B112 are respectively routed. One end of the interconnection A 111 (interconnections A 111-1 to 111-3) is connected to one end of s thick width FIG. 115. Around the thick width FIG. 115, a thick width spacing area 117 is provided based on the design rule.
The interconnection A 111 is routed in the vicinity of the portion connected to the thick width FIG. 115, based on the predetermined design rule. The design rule is the minimum spacing rule. The rule is that a interconnection (111) is bent at the position away from the thick width FIG. (115) by a minimum spacing (119) or more, when the interconnection (111) connected to the thick width FIG. (115) is bent in the same layer as the thick width FIG. (115). This minimum spacing rule, for example, enables the protection against the influence of microloading effect.
Here, the microloading effect implies the phenomenon of the etching trouble in the photolithography. The phenomenon is caused by a fact that an etching manner is different depending on a position, when a pattern having a high density and a pattern having a low density are etched at the same time. In the example of FIG. 1, such effect easily occurs in the connection portion between the thick width FIG. 115 and the interconnection A 111. For this reason, the minimum spacing rule is applied.
In the case of FIG. 1 in the routing, after the interconnection A 111 is routed as close as possible to the thick width FIG. 115, both are connected to each other. For this reason, the bent point is inevitably located at the distance of the minimum spacing 119. Then, the interconnections A 111-1 to A 111-2 connected to the thick width FIG. 115 are placed within a predetermined distance Y defined from the connection portion (the predetermined distance Y>the minimum spacing 119). In such a case, under the design rule, the minimum spacing rule of the thick width FIG. 115 is applied to the interconnections A 111-1 to A 111-2. That is, the thick width spacing area 117 for the thick width FIG. 115 is also enlarged around the interconnections A 111-1 to A 111-2.
A interconnection B 112 can not enter the thick width spacing area 117 because of the design rule. For this reason, the interconnection B 112 is routed along grid lines Tx5-Ty1-Tx6-Ty6-Tx5. That is, the interconnection B 112 is routed so as to make a detour around the thick width spacing area 117, in the vicinity of the connection portion to the thick width FIG. 115. Thus, the interconnection B 112 is routed so as to make the detour around the interconnection A 111-2, although there is no problem on the design even if it is routed only on the grid line Tx5. Consequently, not only the routing resource (routing region) is reduced, but also the interconnection length becomes long.
Thus, in the connection portion between the thick width FIG. 115 and the interconnection A 111, there may be a possibility that the thick width spacing area 117 is wider than necessary. A technique is required for suitably setting a region to regulate the routing in the connection portion between the thick width figure and the thin interconnection. A technique is desired for suitably setting the interconnection laid in the vicinity of the connection region between the thick width figure and the thin interconnection. And, a technique is desired for suitably setting the routing region in the vicinity of the connection region between the thick width figure and the thin interconnection and protecting the interconnection length from being longer than necessary.
In the above-mentioned Japanese Patent No. 3390393, a routing method of a placement and routing system is disclosed. The routing method of a placement and routing system routs interconnections on grids with a predetermined pitch. Via cells are registered in a library and includes a rectangular via, a lower interconnection layer and an upper interconnection layer covering the rectangular via. The routing method includes the steps of: detecting that a spacing between interconnection is less than the minimum spacing with no limitation of facing interconnection length, and equal to or more than the short run spacing allowing a certain spacing with a certain limitation of facing interconnection length when the via cells are placed on adjacent grids facing each other; generating the via cell data modifying the via margin such that the spacing can satisfy the minimum spacing with no limitation of facing interconnection length when via cells are placed in facing each other; and replacing the via cell data to the artwork data corresponding to the via cell after placing and routing by the placement and routing system based on the via cell data.

Semiconductor device, routing method and manufacturing method of semiconductor device


A multi-band phase locked loop employing multiple, switchable voltage controlled oscillators. A single PLL is provided having a different voltage controlled oscillator for each desired frequency band of operation. The transfer function of the phase detector in the phase locked loop is switched responsive to the particular band selected so as to maintain the loop natural frequency at the same point regardless of other changes in the loop transfer function that are associated with operating at alternate frequencies, such as, but not limited to, changes in the frequency slope of the voltage controlled oscillators and changes in the division ratio of the loop divider circuit.

Phase locked loops have varied and wide applications in communications equipment and other fields. Specifically, they can be used wherever it is necessary to synchronize the phase and/or frequency of two signals. In a typical communications type application, a phase locked loop (PLL) is used to synchronize a local oscillator to the frequency (or phase) of an incoming data signal. Phase locked loops also are used to tune a high frequency local oscillator itself to a separate, more stable, lower frequency local oscillator. For instance, in certain communications applications such as digital telecommunications applications, a very high frequency voltage controlled oscillator (VCO) signal may be necessary for synchronizing to an incoming radio frequency signal at, for example, 800 MHz. In order to very precisely control the frequency of the high frequency VCO, the VCO itself may be in a phase locked loop with a crystal oscillator, since crystal oscillators tend to be extremely accurate. However, crystal oscillators typically do not operate at high enough frequencies to be used directly for high radio frequency applications.
In the telecommunications field, incoming data or voice signals are FM modulated on a radio frequency (RF) carrier frequency of, for example, 800 MHz. The incoming data signal is brought down to the base band frequency, e.g., 0-4 KHz, in two steps. First it is frequency down converted into an intermediate frequency e.g., 70 MHz, and then the intermediate frequency (IF) signal is further down converted to the base band. Commonly, the 800 MHz RF signal is converted down to the IF frequency by means of heterodyning the incoming signal with a local oscillator signal that differs from the RF carrier frequency by an amount equal to the intermediate frequency. Thus, in the present example, a local oscillator operating at 870 MHz is needed. Since crystal oscillators that operate at such high frequencies typically are not available, it is common to utilize a voltage controlled oscillator for generating the 870 MHz local oscillator signal. However, since voltage controlled oscillators require highly accurate voltage control to maintain the local oscillator frequency with precision, the high frequency VCOs typically are embedded within a phase locked loop with a crystal oscillator operating at a much lower frequency.
Because the frequency bands dedicated to cellular telephone communications have rapidly become overloaded with communication traffic, both North America and Europe have recently added new radio frequency (RF) band ranges dedicated for cellular telephone communications. Particularly, in North America, where the 824-894 MHz band has been dedicated to cellular telephone communication use, the 1850-1990 MHz band has been added as a second cellular telephone communication band. In Europe, where 890-960 MHz has been dedicated to cellular telephone communications, 1710-1780 MHz has been added as a second frequency band for cellular telephone communications. Within each band there are a number of channels spaced at, for example, 200 KHz intervals so that multiple telephone calls can be supported in the same geographic cell simultaneously.
In view of these new bands for cellular telephone communications, there is a need for cellular telephones and other cellular communications equipment, including facsimile machines, pagers, wireless PCs, wireless modems, etc., that can receive and transmit signals within two separate RF carrier frequency bands, e.g., 824-894 MHz and 1850-1990 MHz.
Accordingly, there is a need for local oscillators which can operate at two very different RF frequencies. For instance, assuming a 70 MHz intermediate frequency, in order for a cellular telephone to be able to receive and transmit data in either band, it should be capable of generating a local oscillator signal in the 894-964 MHz range and a local oscillator signal in the 1920-2060 MHz range. However, while it is not difficult to produce an oscillator capable of generating signals at different frequencies within a tight band, such as 894-964 MHz or 1920-2060 MHz, it is not practical to produce a single oscillator that can produce signals over so broad a range as to cover 894-2060 MHz. Accordingly, multi-band operation requires special design considerations.
One method of providing multi-band capability is to simply provide two individual phase locked loops, one capable of generating local oscillator signals in the 1920-2060 MHz band and the other capable of generating local oscillator signals in the 894-964 MHz band. However, when switching from one band to the other in such a system, there is necessarily a start-up delay while the capacitors and other circuit components of the PLL charge up. In other words, when the telephone switches from one PLL to the other, there will be a long initial settling period before the VCO in the newly activated PLL locks to the desired frequency. Another disadvantage of this solution is that the use of two PLLs increases the circuit componentry in the telephone and thus also increases the size, weight and cost of the equipment.
Another option is to choose an intermediate frequency for the transceiver that is precisely halfway between the two possible operation bands, i.e., in our example in which the two bands are 824-894 MHz and 1850-1990 MHz, the intermediate frequency would be 1350 MHz. In this manner, only a single band PLL is necessary. However, such an IF frequency constraint, particularly at such a high frequency, can lead to significant overall architectural difficulties and disadvantages.
Accordingly, it is an object of the present invention to provide an improved multi-band phase locked loop.
It is another object of the present invention to provide a multi-band phase locked loop with optimal dynamics and close-in-phase-noise with minimal voltage controlled oscillator tuning voltage.
It is a further object of the present invention to provide a multi-band phase locked loop with maximized voltage controlled oscillator frequency slope.
It is yet a further object of the present invention to provide a multi-band phase locked loop with minimal additional circuitry for handling multiple bands.
It is yet another object of the present invention to provide a multi-band phase locked loop with minimal start-up-lock time upon switching from a first voltage controlled oscillator to another voltage controlled oscillator.

Multiband phase locked loop using a switched voltage controlled oscillator


The invention concerns a device for the qualitative or quantitative measurement of a magnetically labelled analyte. The device includes a coil arrangement for measuring the analyte from a sample absorbed in a test base. The coil arrangement includes at least one measuring coil and a reference coil arranged in connection with it. From the signal of the coil arrangement a change in inductance correlating to the content of the magnetically labelled analyte is arranged to be detected. The change in inductance is arranged to be detected from a change (ΔA, Δφ) in amplitude and/or phase appearing in the output signal of the coil arrangement, which is arranged to be measured at the frequency of the input signal. In addition, the invention also relates to a corresponding method.

The present invention concerns a device for the qualitative or quantitative measurement of a magnetically labelled analyte, which device includes a coil arrangement, formed of at least one measuring coil and a reference coil arranged in connection with it, for measuring the analyte from a sample absorbed in a test base, and from the signal of which coil arrangement a change in inductance correlating to the content of the magnetically labelled analyte is arranged to be detected. In addition, the invention also relates to a corresponding method.
Numerous methods and apparatuses for measuring magnetic particles, for example, in analytic tests, are known from the prior art. For example, Finnish patent number 113297 discloses an idea concerning the use of a so-called astatic coil arrangement for measuring an analyte from a sample absorbed in a test base. In it, the coil arrangement is used to detect a change in inductance correlating to the content of a magnetically labelled analyte.
The application of traditional coil technology to such an arrangement, however, is associated with significant problems relating, for example, to the sensitivity of the apparatus. Some examples of these are capacitive parasitic current in the coil loops. Another problem can be mentioned the asymmetry of the coils, which is caused by, for example, the manual winding of the coils.
The magnetism of magnetic particles and thus the change in inductance they create in a coil system is very insignificant compared, for example, to the error signals caused by the environment or the test base itself. Thus the measurement results obtained using the apparatus leave much to be desired.
In addition, due to the test bases according to the prior art, the reactions of the analyte on the test base take place on a very small scale, due, for example, to expensiveness of the reagents. Therefore the positioning of the test base relative to the device, for example, creates a challenging problem while wrong positioning can distort the test results. In addition, the test base places special demands particularly on wrapped coil constructions.
The solutions disclosed in PCT publications WO-2005111614 and WO-2005111615 also make known the application of coil devices in analytic rapid tests. They are based on detecting a change of inductance from a change in resonance frequency. When measuring the change in resonance frequency, the resonance peak of the LC circuit changes to a different frequency when the inductance of a coil or the capacitance of a capacitor changes. However, the low inductance of the coil creates a problem. Parasitic phenomena of all kinds can easily connect to a coil with a low inductance, and thus they can also be distinguished from the signal measured in the frequency form.
PCT publication WO 03/076931 A1 discloses yet another manner of measurement known from the prior art. It too is based on detecting changes in frequency.
Various so-called SQUID-type methods are also known. However, their operating principle demands operation at very low temperatures, at even close to absolute zero. This makes the apparatus complicated, for example, in POCT (point of care testing) applications.

Device for measuring magnetic particles and corresponding method


A computer implemented method for processing tasks is disclosed. The method includes invoking a timed iterator, during an event loop pass, without spawning a new thread, wherein the invoking includes passing a task list and a timeout constraint to the timed iterator. The method further includes executing one or more tasks in the task list for a period of time as specified in the timeout constraint, and relinquishing program control to a caller after the period of time.

1. Field of the Invention
Embodiments of the present invention relate generally to computer user interface (UI) and more particularly handling UI events.
2. Description of the Related Art
Recently, mobile computers and wireless phones have evolved to replace mainstream desktop computers. These mobile devices run on batteries that are charged from time to time. To support applications and usage that require higher processing power, mobile devices are being manufactured with powerful processors and supporting hardware. This increased processing power, however, has a side effect, that is, high capacity batteries are needed and the batteries need to be charged more frequently. To keep the mobile devices light and small, the battery size cannot be increased beyond a reasonable size and users of these mobile devices may not have access to battery charging means at all time. Hence, prolonging the battery charge cycles would prove to be beneficial by designing software applications that exert less burden on the batteries.
It is common for software applications to use multiple threads to implement task parallelism. In an exemplary software application, many threads may be employed as for example, one thread to retrieve data from an external server and another thread to listen to user interaction with the user interface of the exemplary software application. If there were only one thread handling both the above stated exemplary tasks, the application would become unresponsive to user interactions until the first thread finishes retrieving data from the external server. In the meantime, the user may feel as if the application has "hanged" and may try to kill the application. At the very least, such application designs would provide a reduced quality user experience. On the other hand, using multiple threads for different tasks would lead to higher CPU consumption and would result in an undesirable outcome, that is, the battery would need to be charged more frequently.
Further, it may not be possible in some scenarios to have multiple threads. For example, software applications that include legacy code may not be amended to use multiple threads without making them unstable.
Therefore, what is needed is a mechanism to create single threaded software modules that enables an application to be more responsive to user interactions while performing multiple tasks.

Invoking timed iterator for executing tasks within timeout constraint without spawning new thread


A selector device disposed between a transmission and a differential gear includes a first output shaft connected to the transmission, a second output shaft connected to the differential gear, a third output shaft relatively rotatably fitted on an outer periphery of the second output shaft, a planetary gear mechanism having a sun gear connected to the third output shaft and a ring gear connected to the differential gear, a first meshing switching mechanism that is capable of switching between a state in which the first and third output shafts are joined and the second output shaft is detached and a state in which the first to third output shafts are joined, and a second meshing switching mechanism that is capable of joining a carrier of the planetary gear mechanism to a casing.

A continuously variable transmission that converts rotation of an input shaft connected to an engine into reciprocating movements having mutually different phases for a plurality of connecting rods, and converts the reciprocating movements of the plurality of connecting rods into rotation of an output shaft via a plurality of one-way clutches is known from Patent Document 1 below.
Furthermore, a three parallel shaft type automatic transmission equipped with a first input shaft, a second input shaft, and an output shaft, in which an idle gear is meshed with a reverse drive gear provided on the first input shaft and a reverse driven gear provided on the output shaft, the reverse drive gear is joined to the first input shaft via a clutch, and the reverse driven gear is joined to the output shaft via a selector, thus establishing a reverse gear position, is known from Patent Document 2 below.
Moreover, a belt type continuously variable transmission having an endless belt wound around a drive pulley provided on a main shaft and a driven pulley provided on a countershaft, in which a planetary gear type forward-reverse switching mechanism is disposed between the main shaft and the drive pulley to thus make the drive pulley rotate in reverse relative to the main shaft, thereby establishing a reverse range, is known from Patent Document 3 below.


In a wireless network or other communication system, admission of users to the system involves use of a first scheduler, which makes actual scheduling decisions for admitted users, and a second scheduler, which emulates the operation of the first scheduler. The first scheduler is configured to manage access to network resources for users already admitted to the system. The first scheduler is coupled to an admission control module which contains the second scheduler. The second scheduler, also referred to herein as a virtual scheduler, emulates operation of the first scheduler, under an operating scenario involving admission of at least one additional user to the system, in order to generate a performance metric. The performance metric is used to make an admission control decision regarding admission of the at least one additional user to the system.

Wireless networks are often configured to support users having different QoS requirements. Such networks typically use a scheduler, implementing a designated scheduling algorithm, in order to meet the QoS requirements.
The term "scheduler" is used herein in a general sense, and accordingly is intended to encompass resource managers which implement various types of resource allocation algorithms. Such resource allocation algorithms may include, in addition to user selection or user ordering algorithms, power control algorithms, rate control algorithms, transmission rate and encoder format selection algorithms, sub-channel allocation algorithms, frequency hopping algorithms, and so on, in any combination.
If the number of users in the network is not too large, the scheduler is usually able to satisfy all the QoS requirements. However, as the number of users in the network increases, it becomes increasingly important to limit the number of users allowed to access the network and to select an appropriate set of users to ensure that the QoS requirements can be satisfactorily met while at the same time maximizing the utilization of the available network resources. Thus, admission control algorithms are used to ensure that the number of users in the network does not exceed the critical limit beyond which the QoS requirements can no longer be satisfied.
The admission control problem is fairly straightforward in wireless circuit-switched networks, but becomes more difficult in wireless packet data networks. The fundamental reason for the added difficulty is that the resources needed to meet the QoS requirements in wireless packet data networks depend not only on the number of users and their QoS requirements, but also on additional factors, such as the locations, channel qualities and traffic patterns of the users. The issue is further complicated by the fact that the mix of applications present in the network is typically varying over time, such that there is no set limit on the maximum number of users that can be admitted to the network.
Current solutions to the admission control problem have generally considered the problem from a circuit-switched point of view, in which a predetermined number of circuits or other channels are available and have to be shared between the competing users. The basic underlying assumption is that each user consumes a finite number of channels, which is fixed and independent of the user location and channel conditions, as well as the locations and channel conditions of the other users. In addition, the QoS requirements in the circuit-switched context typically include the probability of blocking a new call or the probability of dropping a handoff call. Once a user is accepted to the network, it is assumed that the achieved performance is acceptable to the user and the associated application. However, these assumptions are generally not valid in wireless packet data networks that rely on opportunistic scheduling algorithms to allocate the available resources between competing users.
Furthermore, current admission control techniques often consider only such limiting resources as the processing power of the base station, the number of codes available, the channel elements available, the memory and buffer requirements, or the backhaul capacity. However, in a wireless packet data network which supports multimedia applications, the performance as perceived by each application (e.g., in terms of factors such as the minimum achieved throughput, the average throughput, the average and the maximum delay, or the packet loss rate) is of more importance and is in fact expected to limit the number of concurrent applications that can be supported by the network.
It is therefore apparent that current admission control techniques are often based on assumptions which are not readily applicable to wireless packet data networks, and as a result such techniques do not adequately take certain constraints and requirements into account when deciding on the admission or rejection of a new user. Accordingly, a need exists for improved techniques which overcome one or more of the drawbacks of the conventional approaches as outlined above.

Method and apparatus for quality-of-service based admission control using a virtual scheduler