A centrifugal casting apparatus includes a mold holder placed on a freely rotatable rotary table, and a mold put into and held by the mold holder. The mold holder includes a mold holder body made of a metal material and having a bottomed cylindrical shape, heat insulation members provided on an inner peripheral surface and a bottom surface of the mold holder body, and mold positioning members each made of a ceramic and provided to protrude from the heat insulation member on the bottom surface of the mold holder body. The mold includes a mold body having a cavity into which a molten metal is to be poured, and a mold base provided to the mold body and having mold positioning member insertion holes engageable with the mold positioning members.

1. Field
The present disclosure relates to a centrifugal casting apparatus, or more specifically, to a centrifugal casting apparatus for precisely casting a titanium aluminide precision casting product, a titanium alloy precision casting product, a nickel alloy precision casting product, and the like by centrifugal casting.
2. Description of the Related Art
In the case of a conventional centrifugal casting apparatus, attachment of a mold employs a method of inserting a mold into a cylindrical tube disposed on a rotary table, and positioning and fixing a mold by filling a ceramic heat insulation material and the like in a gap between the cylindrical tube and the mold, or a method of positioning and fixing a mold onto a rotary table by lashing the mold with a belt or the like.
Japanese Patent Application Publication No. Hei 4-81254 (Patent Literature 1) describes a technique for precision centrifugal molding, in which a mold is fastened and fixed to a fixation frame on a rotary base of a centrifugal casting apparatus by using a metal belt.


The present invention relates to a separation medium, comprising an inner core of a porous material provided with charged ligands, and an outer lid comprising a porous material provided with charged ligands, wherein the charge of the ligands in the inner core is opposite that of the charge of the ligands in the lid. The present invention also relates to a method for biomolecule separation comprising applying a sample to the above separation medium, wherein large molecules are prevented from entering the medium by charge repulsion from the medium and small molecules are captured in the inner core.

Within biotechnology, one of the most widely used separation methods is chromatography. The term chromatography embraces a family of closely related separation methods. The feature distinguishing chromatography from most other physical and chemical methods of separation is that two mutually immiscible phases are brought into contact wherein one phase is stationary and the other mobile. The sample mixture, introduced into the mobile phase, undergoes a series of interactions i.e. partitions between the stationary and mobile phases as it is being carried through the system by the mobile phase. Interactions exploit differences in the physical or chemical properties of the components in the sample. These differences govern the rate of migration of the individual components under the influence of a mobile phase moving through a column containing the stationary phase. Separated components emerge in a certain order, depending on their interaction with the stationary phase. The least retarded component elutes first, the most strongly retained material elutes last. Separation is obtained when one component is retarded sufficiently to prevent overlap with the zone of an adjacent solute as sample components elute from the column.
The chromatographic methods suggested up to date are based on different modes of interaction with a target. Thus, for example, in ion-exchange chromatography, the functional groups are permanently bonded ionic groups with their counter ions of opposite charge, while in hydrophobic interaction chromatography (HIC), the interaction between the stationary phase and the component to be separated is based on hydrophobicity. Other chromatographic separation principles are well known to the skilled person in the art.
The stationary phase, also known as the separation matrix, comprises a support, which is commonly a plurality of essentially spherical particles, and ligands coupled to the support. In most separation matrices, the support is porous to allow a larger amount of ligand and consequently more bound target compound in each particle. The support is most often a natural or synthetic polymer and the spherical particles may be produced in a number of different ways. Natural polymers often used for this purpose are the polysaccharides dextran and agarose.
For separation of biomolecules, by chromatographic and batch-wise procedures, the porosity of the beads is very important. One advantage of polymeric media is the opportunity of pore size variation over broad ranges. A general rule, which is accepted throughout the literature, is to use media with large pore sizes for large molecules.
It would be desirable to have alternative ways of separating large molecules without having to use large porosity and which are not limited to separation of large molecules but may also be used to separate molecules of any size.

Separation medium for chromatography of various biomolecules


The invention detailed herein comprises a family of multifunctional acrylate oligomers which are useful as pigment grinding vehicles for use in radiation-curable coating formulations. The multifunctional acrylate resins are formed by the reaction of acrylate monomers and oligomers with β-keto esters (e.g., acetoacetates), β-diketones (e.g., 2,4-pentanedione), β-keto amides (e.g., acetoacetanilide, acetoacetamide), and/or other β-dicarbonyl compounds or Michael “donors” that can participate in the Michael addition reaction. These resin vehicles have a built-in chromophore that enables ink formulations made from their dispersions to cure under standard UV-cure conditions with significantly less photoinitiator than commercial formulations. The resins also exhibit excellent pigment wetting characteristics and can be designed to function as a single dispersion vehicle for different pigments and different ink applications such as screen, flexographic, and lithographic printing.

Increased emphasis on environmental considerations is a driving force advancing the utilization of energy-curable ink technology in the printing and graphic arts industry. Energy-curable inks comprise ultraviolet light (UV-curable) and electron beam radiation (EB-curable) inks. Achieving good quality UV inks is strongly correlated with the final rheology of the system. Rheology is determined by the conformation that the vehicle adopts when wetting the pigment surface. Stable dispersion of the pigment in ink formulations, good ink flow and transfer on press, and subsequent color strength all depend upon pigment wetting.
Pigment wetting can be described as a chemical interaction between the binder and the pigment that helps prevent the flocculation process and enhances the color of the printed ink. The rheological advantages of a well-wetted system are good flow characteristics, low overall ink viscosity, high gloss and proper color development. UV-curable oligomers are available commercially. However, inks based upon conventional oligomers disadvantageously require substantial amounts of various photoinitiators to ensure acceptable photo-cure. Traditional photoinitiators (e.g., benzophenone) can be toxic, expensive, malodorous, and may contribute to film color, which can limit their applicability, in general, and may render them unsuitable for use in white and light-colored inks.
The amount of external photoinitiator in ink formulations can be significantly reduced by using the acrylate oligomer technology described in U.S. Pat. Nos. 5,945,489 and 6,025,410 (both Ashland, Inc.). These patents disclose uncrosslinked resins prepared via the Michael addition reaction of β-dicarbonyl compounds with multifunctional acrylates. The invention disclosed here demonstrates the advantageous use of these uncrosslinked resins alone or modified by reaction with and/or blending with additional materials for grinding different color pigments. These additional materials include a variety of acrylic monomers and oligomers, primary, secondary and tertiary amines, acid functional materials, dispersing agents, pigment wetting aids and others to enhance pigment wetting characteristics. The resulting pigment dispersions can be let-down with appropriate oligomers based on the same Michael Addition resin technology to give UV-curable screen, flexographic, ink-jet and lithographic inks.
The invention detailed herein comprises a family of pigment dispersions for radiation-curable printing ink applications. These dispersions are based on multifunctional acrylate resins formed by the reaction of acrylate monomers and oligomers with β-keto esters (e.g., acetoacetates), β-diketones (e.g., 2,4-pentanedione), β-keto amides (e.g., acetoacetanilide, acetoacetamide), and/or other β-dicarbonyl or Michael "donor" compounds that can participate in the Michael addition reaction combined with a variety of organic and inorganic pigments. An essential novelty of these pigment dispersion vehicles is that the inks based on them will cure under standard UV-cure conditions with very little traditional photoinitiator as compared to commercial formulations which require the addition of substantial amounts of photoinitiator.
The multi-functional polyacrylate oligomers which are used as pigment grinding vehicles in the present invention have dual chemical functionality. That is, they have both acrylic functionality and a labile ketone group that is capable of dissociating, upon exposure to UV radiation, to initiate free radical polymerization of the oligomer.
Pigment wetting and dispersion properties can be modified by various means including the use of additional or supplementary acrylate materials, using various β-dicarbonyl Michael donor compounds, or by simply varying the stoichiometry of the reactants which comprise the oligomer. Inks based on these pigment dispersions may be cured via chemical means, thermally, or by exposure to UV or electron beam radiation. Other materials, both reactive (e.g., conventional polyacrylates or acrylated oligomers) and non-reactive (e.g., thermoplastic polyacrylates such as PMMA), may also be incorporated into dispersion formulations to enhance the pigment wetting characteristics of these resins. Such additives include, but are not limited to, various acrylic monomers and oligomers; primary, secondary, and tertiary amines; and acid-functional monomers and oligomers.
Dispersion systems comprised of traditional monomers and oligomers often have compatibility issues with some of the above additives, giving the formulations chemist fewer options. However, dispersions built from the novel photo-curable Michael Addition resins described herein can incorporate a nearly unlimited variety of additives due to the chemical/architectural control possible in their synthesis. Thus, many more options are available to the formulator who must address challenges specific to each printing application.

This patent is subject to a terminal disclaimer.

Multifunctional acrylate oligomers as pigment grinding vehicles for radiation-curable ink applications

Ashland Licensing and Intellectual Property LLC


A medical electrical lead having a drug which is no more than sparingly soluble in water applied to the electrode surface. In the preferred embodiment the lead of the present invention possesses an electrode treated with a very slightly soluble in water steroid, such as beclomethasone dipropionate anhydrous. Preferably the steroid is applied to the surface of the electrode which contacts tissue when implanted. A method of manufacturing such a lead is also disclosed. Through such a design, a high impedance, low threshold lead which is simple and easy to manufacture is disclosed.

1. Field of the Invention
This invention relates generally to chronically implanted medical electrical leads and, in particular, to cardiac pacing leads which feature a drug which is no more than sparingly soluble in water applied to the electrode surface, e.g. beclomethasone dipropionate anhydrous.
2. Description of the Prior Art
Electrical stimulation of body tissue and organs is often used as a method of treating various pathological conditions. Such stimulation generally entails making an electrical contact between body tissue and an electrical pulse generator through use of one or more stimulation leads. Various lead structures and various techniques for implanting these lead structures into body tissue and particularly the heart have been developed.
For example, a transvenous endocardial lead establishes electrical contact between an electrical pulse generator and heart through placement of a lead in the venous system. Specifically, a transvenous endocardial lead is passed through a vein, with the assistance of a fluoroscope, into the heart where it may be held in contact with the endocardium by the trabeculae of the heart chamber, such as the ventricle. The safety, efficacy and longevity of an electrical pulse generator depends, in part, on the performance of its pacing lead(s).
During the past thirty years, there has been extensive research and development expended to optimize the performance of pacing leads and their reliability. In the early days of cardiac pacing, very high geometric surface area electrodes were employed with bulky and short-lived pacemaker pulse generators. Early investigators, such as Dr. Victor Parsonnet, advanced designs of pacing electrodes for achievement of low polarization and low thresholds while presenting a relatively small effective surface area for the delivery of a stimulating impulse in designs known as differential current density (DCD) of the type shown in U.S. Pat. No. 3,476,116. The DCD electrode (like all pacing electrodes of that time) suffered excessive chronic tissue inflammation and instability and was not pursued commercially.
Subsequent researchers, including Dr. Werner Irnich, explored in considerable detail the electrode-tissue interface and sought to arrive at an optimum exposed electrode surface area for both stimulation thresholds and sensing. See, for example Dr. Irnich, "Considerations in Electrode Design For Permanent Pacing" published in Cardiac Pacing; Proceedings of the Fourth International Symposium of Cardiac Pacing (H. J. Thalen, Ed.) 1973, pages 268-274.
Dr. Seymour Furman also studied the relationship of electrode size and efficiency for cardiac stimulation and presented a ball-tip/exposed spaced coil electrode and a small hemispheric electrode in his article entitled "Decreasing Electrode Size and Increasing Efficiency of Cardiac Stimulation" in Journal of Surgical Research, Volume 11 Number 3, Mar., 1971, pages 105-110. Dr. Furman concluded the practical lower limit of electrode surface area was in the range of 8 sq. mm, observing that impedance increased as an inverse function of the surface area.
Electrodes of many shapes including cylindrical, ball-tip, corkscrew, ring tip and open cage or "bird cage" configurations were pursued with exposed electrode surface areas tending toward 8 sq. mm in the mid 1970's.
More recently, various investigators have emphasized materials and their relationship to the considerations involved in optimizing electrode design. For example, the Medtronic U.S. Pat. No. 4,502,492 discloses a low polarization, low threshold electrode design of the early to mid 1980's which was commercialized as the "Target Tip".RTM. pacing leads in numerous models including Models 4011, 4012, 4511 and 4512. The tip electrode of the Target Tip lead was generally hemispherical and provided with circular grooves. The electrode was fabricated of a platinum alloy, coated over its external surface with a plating of platinum black. The combination of the relatively low electrode surface area and platinum black contributed to state-of-the-art thresholds in that time period. Other manufacturers marketed porous platinum mesh (Cardiac Pacemakers, Inc.), totally porous sintered (Cordis Corporation), glassy and vitreous carbons (Siemens), and laser drilled metal (Telectronics Ppty. Ltd.) electrodes in that same time period.
A considerable breakthrough in the development of low threshold electrode technology occurred with the invention of the steroid eluting porous pacing electrode of Stokes U.S. Pat. No. 4,506,680 and related Medtronic U.S. Pat. Nos. 4,577,642, 4,606,118 and 4,711,281, all incorporated herein by reference. The electrode disclosed in the '680 patent was constructed of porous, sintered platinum or titanium, although carbon and ceramic compositions were mentioned. Within the electrode, a plug of silicone rubber impregnated with the sodium salt of dexamethasone phosphate or a water soluble form of other glucocorticosteroids was placed in a chamber. The silicone rubber plug allowed the release of the steroid through the interstitial gaps in the porous sintered metal electrode to reach into the tissue and prevent or reduce inflammation, irritability and subsequent excess fibrosis of the tissue adjacent to the electrode itself.
In particular, the steroid is believed to act upon and inhibit the inflammatory response of the body. The presence of the electrode, an object foreign to the body, activates macrophages. This occurs approximately three days after implant. Once activated the macrophages attach themselves to the surface of the electrode and form multi-nucleated giant cells. These cells, in turn, secrete various substances, such a hydrogen peroxide as well as various enzymes, in an effort to dissolve the foreign object. Such substances, while intending to dissolve the foreign object, also inflict damage to the surrounding tissue. When the surrounding tissue is the myocardium, these substance cause necrosis. These areas of necrosis, in turn, cause the electrical characteristics of the electrode tissue interface to degrade. Consequently pacing thresholds rise. Even after the microscopic areas of tissue die the inflammatory response continues and approximately seven days after implant the multi-nucleated giant cells cause fibroblasts to begin laying down collagen to replace the necrosed myocardium. This continues until completed and the electrode is encapsulated by a thick layer of fibrotic tissue, approximately twenty-eight days after implant. Typically the inflammatory response ends at this time.
Steroid, it is believed, inhibits the inflammatory response by inhibiting the activation of the macrophages. Because they do not form multi-nucleated giant cells, the subsequent release of substances to dissolve the object and which also destroy the surrounding tissue is prevented. Thus the necrosis of any tissue by the inflammatory response is minimized as well as the formation of the fibrotic capsule. Minimizing each of these reactions also minimizes the concomitant deterioration of the electrical characteristics of the electrode-tissue interface.
Thus, the incorporation of steroid elution permitted pacing leads to have a source impedance substantially lower as compared to leads featuring similarly sized solid electrodes. Leads which elute steroid also presented significantly lower peak and chronic pacing thresholds than similarly sized solid or porous electrodes.
One example of a lead which eluted steroid meeting widespread commercial success is the Medtronic Model 5534 CAPSURE Z.TM. lead. In particular this lead features an electrode with an exposed geometric surface area in the range of 0.1-4.0 sq. mm , preferably between 0.6 and 3.0 sq. mm, with about 1.0 sq. mm providing optimum performance. The lead had a pacing impedance of 1400+/-260 ohms and a source impedance of about 1650+/-410 ohms in both chambers of the heart. The electrode was hemispherical as exposed to the tissue and had a diameter of approximately 1 millimeter. The electrode was further fabricated of platinized porous platinum (or other porous electrode material) and required an annular shaped monolithic controlled release device (MCRD) loaded with an anti-inflammatory agent soluble with water which would then elute out of the lead and into the surrounding tissue, e.g., the steroid dexamethasone sodium phosphate. This water soluble steroid also was deposited within the pores of the porous platinum electrode.
Incorporating steroid so that it will elute from a lead, however, dramatically increased the relative complexity of lead construction , especially as compared to past, non-steroid eluting leads. For example, leads which elute steroid typically require an MCRD to contain the steroid and to thereafter slowly leach out the water soluble steroid into the surrounding tissue. Typically MCRDs were constructed from silicone rubber. Steroid eluting leads also required an area near the electrode in which to house the MCRD, as well as a high degree of dimensional control over the electrode in order to ensure proper steroid elution. Moreover, because steroids which elute within the body, such as the sodium salt of dexamethasone phosphate, often degrade at high temperatures, thermal processing during the production of a steroid eluting lead was not allowed once the MCRD was installed. Setting aside a volume near the electrode tip to house the MCRD, however, also tended to increase lead body stiffness in that area.

Method of making medical electrical lead


Embodiments of the present disclosure describe a photodetector and/or photovoltaic device comprising a semiconducting substrate and a solution including at least GQD and PEDOT:PSS, the solution deposited as a layer on the semiconducting substrate. Embodiments of the present disclosure further describe a method of fabricating a photodetector and/or photovoltaic device comprising contacting an amount of GQD with PEDOT:PSS sufficient to form a solution; and depositing the solution as a layer on a semiconducting substrate.

GaN-, Si-, and InGaAs-based detectors have been widely used for ultraviolet (250 nm to 400 nm), visible (450 nm to 800 nm), and infrared (900 nm to 1700 nm), respectively. However, the cost of these photodetectors is high and the design is complex because these detectors require cooling systems in order to increase sensitivity and reduce noise levels. While functional 2D photodetectors with ultrahigh gain, photodetectors for harsh electronics, and see-through solar-blind photodetectors have been successfully fabricated, these functional photodetectors typically require high operation voltage and have a limited detection wavelength range. As a result, the potential of using these devices in practical applications is inhibited.
High-detectivity polymer photodetectors with spectral response from 300 nm to 1450 nm have also been reported. For instance, photodetectors based on poly(5,7-bis(4-decanyl-2-thienyl)-thieno(3,4-b)diathiazole-thiophene-2,5) (PDDTT), solution-processed perovskite materials, and CdS and PbS quantum dot-based photodetectors have been fabricated. However, compared to Si photodetectors, the detectivity of organic based photodetectors is still relatively low in certain wavelength regions. In addition, the fabrication of Cd and Pb based quantum dots require toxic materials.
In considering the development of next generation photovoltaic applications, a major goal includes weak light and omnidirectional light harvesting. Most light is diffused or scattered through the atmosphere as it reaches the earth. Under an overcast sky, over 90% of the total incident solar radiation is diffused. To date, photon management techniques that enable the omnidirectional light detectability such as hierarchical surface engineering, fabrication of graded refractive index coating, employing colloidal nanospheres, and utilization of periodic nanopillar arrays have been applied in various optical devices. These omnidirectional light-harvesting techniques, however, require complex fabrication processes that result in unwanted defects, recombination sites, and contaminations that deteriorate performance with respect to omnidirectionality and thus require additional treatment procedures. Therefore, it is of great importance to develop more straightforward outdoor weak light harvesting techniques with extraordinary omnidirectional light absorption properties that can also be used, for example, in indoor applications such as smart home and intelligent building.

KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY


A method for preparing lithographic printing plates is disclosed. Imaged positive-working, thermally imageable, multi-layer imageable elements useful as lithographic printing plate precursors are developed using solvent based developers. Development may be carried out by immersing the imaged imageable element in the developer.

In lithographic printing, ink receptive regions, known as image areas, are generated on a hydrophilic surface. When the surface is moistened with water and ink is applied, the hydrophilic regions retain the water and repel the ink, and the ink receptive regions accept the ink and repel the water. The ink is transferred to the surface of a material upon which the image is to be reproduced. Typically, the ink is first transferred to an intermediate blanket, which in turn transfers the ink to the surface of the material upon which the image is to be reproduced.
Imageable elements useful as lithographic printing plates, also called printing plate precursors, typically comprise an imageable layer applied over the surface of a hydrophilic substrate. The imageable layer includes one or more radiation-sensitive components, which may be dispersed in a suitable binder. Alternatively, the radiation-sensitive component can also be the binder material.
If after imaging, the imaged regions (the regions struck by imaging radiation) are removed in the developing process, revealing the underlying hydrophilic surface of the substrate, the plate is called a positive-working printing plate. Conversely, if the unimaged regions (the regions not struck by the imaging radiation) are removed by the developing process and the imaged regions remain, the plate is called a negative-working plate. In each instance, the regions of the radiation-sensitive layer that remain (i.e., the image areas) repel water and accept ink, and the regions of the hydrophilic surface revealed by the developing process accept water, typically a fountain solution.
Imaging of the imageable element with ultraviolet and/or visible radiation is typically carried out through a mask, which has clear and opaque regions. Imaging takes place in the regions under the clear regions of the mask but does not occur in the regions under the opaque regions of the mask. The mask is usually a photographic negative of the desired image. If corrections are needed in the final image, a new mask must be made. This is a time-consuming process. In addition, the mask may change slightly in dimension due to changes in temperature and humidity. Thus, the same mask, when used at different times or in different environments, may give different results and could cause registration problems.
Direct digital imaging of imageable elements, which obviates the need for imaging through a negative, is becoming increasingly important in the printing industry. Multi-layer positive-working imageable elements for the preparation of lithographic printing plates have been developed for use with infrared lasers. These elements comprise at least two layers, an underlayer and an imageable layer, over a substrate with a hydrophilic surface. These elements are described, for example, in Shimazu, U.S. Pat. No. 6,294,311, and U.S. Pat. No. 6,352,812; Patel, U.S. Pat. No. 6,352,811; and Savariar-Hauck, U.S. Pat. No. 6,358,669, and U.S. Pat. No. 6,528,228; the disclosures of all of which are all incorporated herein by reference.
To obtain a printing plate with imagewise distribution of printable regions, it is necessary to remove the imaged regions of the imageable element by contacting the imaged imageable element with a suitable developer. High pH developers have been used for multi-layer positive-working imageable elements. High pH developers typically have a pH of at least about 11, more typically at least about 12, even more typically from about 12 to about 14. High pH developers also typically comprise at least one alkali metal silicate, such as lithium silicate, sodium silicate, and/or potassium silicate, and are typically substantially free of organic solvents. The alkalinity can be provided by using a hydroxide or an alkali metal silicate, or a mixture. Preferred hydroxides are ammonium, sodium, lithium and, especially, potassium hydroxides. The alkali metal silicate has a SiO2 to M2O weight ratio of at least 0.3 (where M is the alkali metal), preferably this ratio is from 0.3 to 1.2, more preferably 0.6 to 1.1, most preferably 0.7 to 1.0. The amount of alkali metal silicate in the developer is at least 20 g SiO2 per 100 g of composition and preferably from 20 to 80 g, most preferably it is from 40 to 65 g.
Because of their high pH, disposal of these developers without creating environmental problems can be difficult. In addition, these developers absorb carbon dioxide from the air causing their activity to change during use.
Spray-on processors, which rely on the force of the developer spray and the brushes and plushes to dislodge the imaged regions of the element, have typically been used. In these processors, the developer is sprayed onto the imaged imageable element, but the element is not immersed in the developer.
Thus, it is difficult to control the temperature of the developer.
Thus, a need exists for a method for preparing imaged multi-layer positive-working imageable elements that does not suffer from these disadvantages.

Method for preparing lithographic printing plates


Apparatus and method for adaptively controlling a bit rate of a video transcoder are disclosed. Logarithmic R-Q characteristics obtaining the adaptive R-Q characteristics suitable to characteristics of an inputted image are proposed, and the parameter (β) compensating the difference between the coding efficiency of MPEG-1 and the coding efficiency of MPEG-4 is not fixed as a specific value but changed adaptively according to the characteristics of an image. Accordingly, an accurate quantization parameter of MPEG-4 is generated. Thus, on the basis of the proposed concepts, the bit rate is adaptively controlled when the bit stream of MPEG-1 is converted into a bit stream of MPEG-4, so that the picture quality (PSNR) can be heightened and more accurate output bit rate can be obtained.

1. Field of the Invention
The present invention relates to bit rate conversion of a video transcoder and, more particularly, to an apparatus and method for adaptively controlling logarithmic R-Q model-based bit rate.
2. Description of the Background Art
With the advent of a video compression technology, digital video signal can be transmitted through diverse types of channels including the Internet, a radio network and an ATM network. Therefore, a future video service should take is a heterogeneous video coding standard, as well as a heterogeneous network environment, into account.
Up to now, MPEG-1 has been used as a general video coding standard for a digital storage medium and CD-ROM application and numerous video contents are created to an MPEG-1 bit stream. As video transmission at a low bit rate such as a moving environment is in increasingly demand, an MPEG-4 has been introduced as one of main stream technique resistant to a channel error.
Having a bit rate of about 1.5 Mbit, the MPEG-1 is not suitable for a radio environment which requests a low bit rate. In comparison, the MPEG-4 has a high compression rate and adopts various error-resistance techniques, so that it is suitable for a radio environment with a high error rate and low channel band width.
Therefore, by transcoding the MPEG-1 video contents stored in a server to the MPEG-4 with the low bit rate, various video contents can be effectively transmitted from the server to a mobile terminal having an MPEG-4 decoder through a radio environment. As a related substantial application field, a VOD (Video on Demand) or a streaming video service allows the mobile terminal with the MPEG-4 to receive MPEG-1 video contents which has been previously compressed and stored.
In order to provide such service, the high bit rate of the MPEG-1 which has been previously compressed and stored should be converted into an MPEG-4 bit stream of a low bit rate as requested by the mobile terminal with the MPEG-4, for which a video transcoder is proposed to perform the conversion operation.
FIG. 1 illustrates a structure of a conventional video transcoder for the bit rate conversion.
With reference to FIG. 1, the conventional video transcoder includes a variable length decoder (VLD) 10, an inverse quantizer (IQ1) 12, an adder 14, a quantizer 16, a variable length coder (VLC) 18, an inverse quantizer (IQ2) 20, an adder 22, a frame memory 24, a motion compensator 26, a bit rate controller 28 and an MPEG-4 syntax generator 30.
The VLD 10 decodes an MPEG-1 bit stream with a bit rate (R1), and outputs a quantization parameter (QP) and a DCT coefficient.
The inverse quantizer 12 inversely quantizes the DCT coefficient to a quantization parameter (QP) and outputs it to the adder 14. Then, the adder 14 adds the motion compensation value at the DCT domain outputted from the motion compensator 26 and the DCT coefficient outputted from the inverse quantizer 12.
The quantizer 16 quantizes the DCT coefficient outputted from the adder 14 with the quantization parameter (QP) outputted from the bit rate controller 28, and outputs it to the VLC 18. Then, the VLC 18 codes the quantized DCT coefficient with the MPEG-4 syntax outputted from the syntax generator 28 and outputs an MPEG-4 bit stream with a bit rate (R2).
At this time, the motion compensator 26 generates a motion compensation value at the DCT domain by using the motion vector (MV) outputted from the VLD 10 and a reference DCT frame stored in the frame memory 24, and the adder 22 subtracts the outputs of the inverse quantizers 12 and 20 and adds the corresponding subtraction value to the motion compensation value to generate a reference frame to be stored in the frame memory 24. The MPEG-4 syntax generator 30 generates an MPEG-4 syntax from the MPEG-1 bit stream.
In this manner, the video transcoder transcodes the MPEG-1 bit stream with the high bit rate (R1) to the MPEG-4 bit stream with the low bit rate (R2), and a target bit rate of the MPEG-4 is performed under the control of the bit rate controller 28.
The bit rate controller 28 receives the quantization parameter (QP) of the MPEG-1 which has been decoded in the VLD 10 and outputs a quantization parameter for controlling the bit rate of the MPEG-4 to the quantizer 16.
The up-to-date method for controlling the bit rate of the MPEG-4 by the bit rate controller of the video transcoder is 'a new requantization method for MPEG-1 to MPEG-4 transcoder' disclosed in pages 13–16 of an article presented by S. C. Heo, K. D. Seo, K. C. Roh and J. K. Kim in the IEEE ICME (IEEE Int. Conf. On Multimedia and Expo 2001) held in Tokyo.
In the above article, two steps are formed to control the bit rate of MPEG-4. First step is determining a suitable quantization parameter on the basis of an existing general R-Q (rate-quantization) model, and the second step is finally obtaining a quantization parameter of MPEG-4 in consideration of difference between a compression efficiency and quantization method of MPEG-1 and those of MPEG-4.
FIG. 2 is a block diagram of a bit rate controller for controlling a bit rate of MPEG-4 in accordance with the conventional art.
With reference to FIG. 2, the conventional bit rate controller includes an R-Q modeling unit 20 and a quantization parameter determining unit 22.
The R-Q modeling unit 20 calculates a target quantization parameter [Q1T(n,m)] of MPEG-1 by adopting an R-Q model to the inputted quantization parameter [Q1(n,m)] of MPEG-1. In this case, 'n' indicates an order of pictures and 'm' indicates an index representing the order of macro blocks in the picture. The R-Q (rate-quantization) model has been proposed by Ding in IEEE Trans. On circuits and systems for video technology, February 1997.
The quantization parameter determining unit 22 receives the target quantization parameter [Q1T(n,m)] and calculates a quantization parameter [Q2(n,m)] of MPEG-4 to obtain a bit rate of MPEG-4 in consideration of the difference in the coding efficiency between MPEG-1 and MPEG-4 and coding and the difference of the coding methods of the quantization parameter between two coding standards.
That is, the coding efficiency of MPEG-4 is better than that of MPEG-1 by about 10–20%. Thus, in order to reflect the coding efficiency, β parameter has been introduced to the quantization parameter determining unit to reflect the coding efficiency. In addition, in case of MPEG-4, in order to prevent a rapid change of picture quality, a changeable value of the quantization parameter between neighboring macro blocks is limited to ±2, while there is no such limitation in MPEG-1.
Thus, in order to resolve such difference, the quantization parameter determining unit 22 uses an gradual approach function (GAF).
The quantization parameter determining unit 22 calculates a quantization parameter [Q2(n,m)] for MPEG-4 by adopting the β parameter and the GAF to the target quantization parameter [Q1T(n,m)]. In addition, the quantization parameter determining unit 22 detects α(n) indicating a difference between a target bit rate per 1 frame and an actually generated bit count and feed it back to the R-Q modeling unit 20. Then, the R-Q modeling unit 20 increases or decreases bit count transmission as much as α(n) in the next frame.
Accordingly, the quantizer 16 quantizes the DCT coefficient outputted from the adder 14 with the quantization parameter [Q2(n,m)], thereby obtaining a target bit rate of MPEG-4.
As mentioned above, the bit rate controller obtains the target quantization parameter [Q1T(n,m)] by adopting the R-Q model to the quantization parameter [Q1(n,m)] of MPEG-1. However, the R-Q modeling unit of the bit rate controller uses only the fixed R-Q model without considering characteristics of an input image.
That is, the conventional bit rate controller has a problem that it uses a fixed model that is not changeable regardless of an image for the R-Q model, a core of a bit rate control algorithm, it can not control accurately the bit rate. Because of this problem, an accurate bit rate is not assigned to each picture, resulting in that a picture quality is degraded or picture quality between pictures is provided a method for adaptively controlling a bit rate of a video transcoder including the steps of: converting a bit stream of MPET-1 into a DCT coefficient; generating a quantization parameter of MPEG-4 by reflecting a difference of a logarithmic R-Q model and a coding efficiency for a quantization parameter of MPEG-1; quantizing the DCT coefficient with the generated quantization parameter of MPEG-4 and outputting an MPEG-4 bit stream.
In the method for adaptively controlling a bit rate of a video transcoder of the present invention, the step of generating a quantization parameter of MPEG-4 includes: setting an initial value of a control parameter; determining a quantization parameter of a target MPEG-1 by adopting a logarithmic R-Q model to a quantization parameter of MPEG-1; adjusting the quantization parameter of the target MPEG-1 by using a correction parameter of a coding efficiency between MPEG-1 and MPEG-4; and outputting the quantization parameter of MPEG-4 by adopting a gradual approach function to the adjusted quantization parameter; and updating a control parameter when one picture is completely processed.
To achieve at least these advantages in whole or in parts, there is further provided a method for adaptively controlling a bit rate of a video transcoder including the steps of: setting an initial value of a control parameter; determining a quantization parameter of a target MPEG-1 by adopting a logarithmic R-Q model to a quantization parameter of an input MPEG-1; adjusting the quantization parameter of the target MPEG-1 by using a parameter indicating a difference of a coding efficiency between MPEG-1 and MPEG-4; calculating a quantization parameter of an output MPEG-4 by adopting a gradual approach function to the adjusted quantization parameter of the target MPEG-1; calculating a difference between a target bit count for each picture and an actually generated bit count and feeding back the difference to the quantization parameter determining step; and updating a control parameter when one picture is completely processed.
To achieve at least these advantages in whole or in parts, there is further provided an apparatus for adaptively controlling a bit rate of a video transcoder including: a logarithmic R-Q modeling unit for outputting a quantization parameter of a target MPEG-1 by adopting a logarithmic R-Q model to a quantization parameter of an input MPEG-1; a quantization parameter adjusting unit for adjusting a quantization parameter of the target MPEG-1 with a correction parameter of a coding efficiency; quantization parameter determining unit for outputting a quantization parameter of an output MPEG-4 by adopting an gradual approach function to the adjusted quantization parameter of the target MPEG-1; and bit count computing unit for calculating a bit count difference between the nth picture of the target MPEG-1 and that of the output MPEG-4, and feeding back the bit count difference to the logarithmic R-Q modeling unit.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.

Apparatus and method for adaptively controlling bit rate of video transcoder


Automatic Trailer Control System--containing four principle inventions. One part of the invention provides automatic trailer steering control to the trailer to cause a delayed turn of the trailer steering mechanism while maneuvering a turn. A second part of the invention provides an electro-magnetic braking system, to the trailer, which is controlled by the same Microcomputer system that controls the trailer turning. The third part of the invention utilizes the electro-magnetic braking system as an alternator/generator to be used as an auxiliary battery charging system. A fourth part of the invention uses the electro-magnetic braking system as a motor to drive the trailer wheels as an assist during trucking operations. All operational functions are controlled by the Microcontroller based control system mounted on the trailer rear wheel platform. Sensors are placed on the truck/trailer operating system to obtain operational information needed for the control of the system.

1. Field of the Invention
This invention provides a total system implementation of multiple products. These products are designed to be integrated into this closed loop control system and each product is configured to provide multiple functions while operating in the system configuration. The only relationship to previous concepts is the basic physics of the functions being applied. By using these basic concepts and expanding the products for multiple functions this invention provides a total system application dearly needed by the whole world.
This invention provides a basic control electronics system which incorporates all aspects of control and safety of operation to the Truck/Trailer system. The Microcontroller electronics provides the intelligence as the heart of the system and the link to the power driving elements in the system. This concept is equally applicable to automobiles, pickups, or any vehicle.
The first feature and primary issue for this invention is to provide an Automatic control to the Truck/Trailer during all operational maneuvers. During a simple operation of maneuvering a Truck/Trailer around a corner, the operator must negotiate the turn by providing a wide margin to clear the corner. With this system, the Control System will delay the turning of the Trailer by continuing in the forward direction until the turn can be made without interference. During this operation the platform will be rotating in the opposite direction of the turn to maintain a forward movement. After a calculated travel distance, based upon detected trailer wheel speed from the Electro-Magnetic motor 15 and the truck speedometer pickoff 26, the system determines when the trailer can be safely turned, then the system will rotate the trailer platform or wheel assemblies to make the turn as did the truck. During this turn the motor drive electronics are engaged to accelerate the trailer in the forward direction to eliminate side drag from the truck. The Truck can then make this turn without having to negotiate for clearance and simply turn as it would without a trailer attached. This technique will prevent mishaps from occurring during these simple maneuvers and provide the operator with a much greater level of safety. At times the failure to properly negotiate a turn has caused severe damage to the vehicle or other property and in some cases injury to other persons in their own vehicles.
A second feature is the Electro-Magnetic Braking System. This subsystem is also controlled by the Microcontroller and provides a pulse-width drive control to the Electro-Magnetic trailer braking system. This feature will provide the operator with a significant margin of safety during normal operations. The control will provide braking to the Trailer in a manner which will safely bring the vehicle to a stop, and will do so in such a manner as to keep the wheels from locking-up. The "H" bridge Power Field Effect Transistor (FET) driver output from the Power Drive Assembly provides the source of drive power which is transmitted to the Electro-Magnetic assembly. This power drive can be applied as a shunt (short) across the magnetic windings or by reversing the polarity of the drive and providing a reverse drive to the motor (same drive approach as when backing-up). The optimum, and most sure method, is to reverse the polarity of the drive. The reverse drive effect will transfer the load from the magnetic drive assembly 25 to the rotor 24 in the assembly. This creates a loading effect on the wheel rotor and a braking effect on the assembly. To minimize the heating effects from this load, the application of the reverse drive to the magnetics is applied by using the Pulse-Width output drivers. In conjunction with the reverse drive, the Electro-Magnetic Assembly will contain heatsink fins to dissipate heat generated during the braking operation. The application of the pulses are controlled to maintain maximum braking effectivity and avoid locking-up the brakes. The application of this system will significantly reduce major problems the operators experience from trailers jackknifing and causing major tie-ups on the roads and freeways.
In addition to the braking feature a third feature is made available, the Electro-Magnetic brakes can also be used as a power source for generating power to recharge the trailer control system battery. When the Electro-Magnetic braking assembly is not in use as a brake it is reconfigured electronically as a generator which provides a power source for recharging the system battery. This is the same approach that is presently used in the alternators installed in all vehicles. The voltage regulation is controlled by an electronic module built into the alternator.
As a fourth feature, the Electro-Magnetic braking assembly can also be reconfigured as a motor which provides additional driving power to the truck when transitioning uphill or as an aid during normal operations. The primary aid from the motor will occur during uphill transitions where the motor assist will enable the truck to overcome the significant overloading effects from uphill transitions. The power output drivers contain an "H" bridge drive FET output, which is controlled by the Microcontroller, to provide the Pulse-Width drive to the Electro-Magnetic assembly to drive it as a motor. The drive power to the wheels is determined by the width of the power driven pulse to the motor. As the Pulse-Width increases, the power is increased to the motor.
2. Description of the Prior Art
The concept of this design is unique in that a total system concept is conceived as a combination of multiple products. These products are reconfigured to merge into the system as a total closed loop control system. The closest products known relating to this system are reflected in the following patents.
______________________________________ PATENT NO. INVENTOR ______________________________________ 5,054,587 Norio Matsui 5,023,499 Touro Kuwahara 4,955,630 Axel Ogren 4,824,135 Donald McGregor 4,463,966 Ronald Stoddard 3,834,480 Leland McGee 3,564,311 Hartwig Beyersdorf ______________________________________
These patents disclose similar features to the stated invention.