A semiconductor device, equipped with a circuit for regulating an internal power source by using a plurality of fuses, includes a fuse group for trimming a power source, having a plurality of fuses capable of being cut off so as to regulate a voltage level of an internal power source; a decoding unit for fuse information of the internal power source, for decoding fuse information in response to a cut-off state of each of these fuses and outputting bit information corresponding to the thus regulated voltage level of the internal power source; and a voltage level regulating unit for a spare fuse pattern, for generating at least one spare pattern other than patters of the bit information used at present and for regulating the voltage level of the internal power source. The voltage level of the internal power source is regulated so that the spare pattern corresponds to any one of the patterns of the bit information used at present.

1. Field of the Invention
The present invention relates to a semiconductor device equipped with a circuit for regulating a voltage level of an internal power source by using a plurality of fuses after a fabrication of a semiconductor chip.
More specifically, in a semiconductor device capable of trimming a voltage level of an internal power source supplied to sources or drains of MOS (Metal-Oxide Semiconductor) transistors by a fuse circuit having a plurality of fuses, so as to reduce a fluctuation of this voltage level to minimum (that is, semiconductor device capable of compensating for a fluctuation component in the above voltage level that is brought about owing to the level fluctuation of the above voltage level), the present invention relates to a circuit technology which can attain a stable circuit operation, without bringing about an abnormal operation inside the semiconductor chip even when the problems associated with a glow-back or an incomplete cut-off state (i.e., insufficient cut-off state) of each of some fuses, occur.
2. Description of the Related Art
In a semiconductor device having a semiconductor chip, in general, the requirement for lowering a voltage level of a power source supplied to MOS transistors, etc., as much as possible has become stronger, in order to reduce power consumption due to the current flowing through a plurality of MOS transistors fabricated inside the semiconductor chip and to improve the endurance against the voltage applied to each of the oxide films formed in these MOS transistors.
As the voltage level of the power source supplied to the MOS transistors, etc., inside the chip is lowered so as to satisfy the requirement described above, influences due to the fluctuation of the voltage level of an external power source become greater. Therefore, it is customary to lower an external power source (VCC) to a constant voltage level inside the chip and to use this step-down voltage as the voltage level of an internal power source (VII), in order to keep flat (i.e., keep constant) the voltage level of the internal power source, by using an internal power source which is not affected by the fluctuation of the voltage level of the external power source.
FIG. 1 is a graph showing operations of the external power source (VCC) and the internal power source (VII). Here, an explanation will be given for the case in which the operating voltage Vcc of the external power source (VCC) is set to 3.3 V as a typical example.
According to specifications placed in catalogues of products of semiconductor devices in which the operating voltage Vcc=3.3 V is stipulated as the external power source (VCC), a recommended operating condition (i.e. recommended operating range) of each of these products of semiconductor devices is Vcc=3.0 V to 3.6 V. However, an internal power source (VII) which is controlled so as to become flat (i.e., remain constant) at the operating voltage Vo of 2.4 V (here, the value of 2.4 V is a design target value or "default value", and an operating voltage range of the internal power source (VII) ranging from 2.0 V to 2.8 V, for example, is permitted) is used in practice so as to flatten the voltage level as described above. It should be noted, however, that there is the case in which an arbitrary voltage level of the internal power source within the operating voltage range described above cannot be obtained after fabrication of the chip, owing to the fluctuation of process conditions during the fabrication of the chip, or the like. In such a case, the voltage level of the internal power source must be regulated by a fuse circuit having a plurality of fuses as will be described later.
FIGS. 2 and 3 are the first part and the second part of a circuit block diagram showing the mode of the regulation of the internal power source voltage level in a semiconductor device according to the prior art, respectively. In this case, the construction of the semiconductor device is shown in a simplified form.
In the semiconductor device according to the prior art shown in FIG. 2, there are disposed a fuse circuit 120 for trimming an internal power source which is equipped with a plurality of fuses F each being capable of taking a cut-off state as a circuit having the function of regulating a voltage level of an internal power source; and a decoding circuit 130 for fuse information of an internal power source, which decodes fuse information (i.e., output signals rff0x, rff1x and rff2x of the fuse circuit for trimming the internal power source) relating to the cut-off state of the fuses F obtained from the fuse circuit 120, and which converts the above fuse information to bit information associated with the voltage level of the internal power source (decode signals f1t0x to f1t4x and f1t0z to f1t4z).
In the semiconductor device according to the prior art shown in FIG. 3, further, there are disposed an internal power source control circuit 50 which outputs a gate control voltage Vrfv for generating a voltage level of a design target value in accordance with the bit information outputted from the decoding circuit 130 for fuse information of the internal power source; and an internal power source generating circuit 60 which lowers the external power source VCC in accordance with the gate control voltage Vrfv outputted from the internal power source control circuit 50 and which converts the external power source to the internal power source VII (i.e., a step-down internal power source).
In the circuit construction described above, the final voltage level of the step-down internal power source VII is decided by the fuse circuit 120 for trimming the internal power source, the decoding circuit 130 for fuse information of the internal power source, the internal power source control circuit 50 and the internal power source generating circuit 60.
In the example of the circuit for regulating the voltage level of the internal power source described above, a transistor 61 for stepping down the external power source inside the internal power source generating circuit 60 includes an N channel type transistor, but the transistor 61 is not particularly limited to this N channel type transistor. The method of stepping down and controlling the power source converts the external power source VCC to the internal power source VII by regulating the potential of the gate of the transistor 61 for stepping down the external power source. In other words, one of the junctions (nodes) of a plurality of level regulating resistors 57 is selected by operating any one of a plurality of transfer gates 0a to 4a inside the transfer gate circuit unit 56 in the internal power source control circuit 50 shown in FIG. 3, and it is possible to carry out the conversion operation from the external power source VCC to the internal power source VII by regulating the voltage level of the output node (gate control voltage (Vrfv)). Each of a plurality of transfer gates described above includes a CMOS transistor having a P channel type transistor and an N channel type transistor. The arrow attached to the P channel type transistor represents back-bias applied to the gate of the P channel type transistor. Incidentally, the circuit construction of the internal power source control circuit 50 shown in FIG. 3 will be described in further detail in the paragraph "DESCRIPTION OF THE PREFERRED EMBODIMENTS".
The voltage level of the gate control voltage Vrfv is originally determined by the internal power source control circuit 50 shown in FIG. 3. However, if semiconductor devices are fabricated and manufactured into products under an undesirable condition such as a fluctuation of process conditions during the fabrication of the chip, the internal power source VII having a design target voltage level, that is, the gate control voltage Vrfv having a necessary voltage level, cannot be outputted in most cases, as shown in FIG. 1.
The prior art example shown in FIGS. 2 and 3 is equipped with the fuse circuit 120 for trimming the internal power source and the decoding circuit 130 for fuse information of the internal power source 130 in order to accurately regulate the voltage level of the internal power source VII after the process for fabricating the chip is completed.
The prior art example described above is of the type which can regulate the voltage level of the gate control voltage Vrfv to the design target voltage level by regulating the resistance value of the level regulating resistors 57 inside the internal power source control circuit 50. Fuse information relating to the cut-off state of each of a plurality of fuses (for examples, three pairs of fuses) inside the fuse circuit 120 for trimming the internal power source shown in FIG. 2, are inputted in the form of the output signals rff0x to rff2x of the three fuse circuits for trimming the internal power source to three inverters 300 to 320 for decoding the fuse information inside the decoding circuit 130 for fuse information of the internal power source, through level converting circuit units 200 to 220, respectively. NAND gates 330 to 334 for generating the fuse information patterns, inside this decoding circuit 130 for fuse information of the internal power source, decode the fuse information on the basis of the input signals (non-inversion signals) and the output signals (inversion signals) of the inverters 300 to 320 for decoding the fuse information. Further binary bit information associated with the voltage levels of the internal power source (decode signals f1t0x to f1t4x and f1t0z to f1t4z) is outputted through the inverters 340 to 344 for generating the fuse information patterns. In other words, any one of a plurality of transfer gates 0a to 4a of the internal power source control circuit 50 shown in FIG. 3 is operated on the basis of the decoding result of the fuse information described above so as to regulate the resistance value of the level regulating resistor 57 and to thus generate the gate control voltage Vrfv of an arbitrary level. By the way, the fuse circuit 120 for trimming the internal power source and the decoding circuit 130 for the fuse information of the internal power source are hereby constituted by the inverters and the NAND gates, but they should not be limited to the inverters and the NAND gates.
In the prior art example described above, the level regulating resistors 57 inside the internal power source control circuit 50 are selected in accordance with five bit information patterns shown at the right part of FIG. 3 so as to trim the voltage level of the internal power source. The design target value (i.e. default value) of the voltage level of the internal power source is the center value of the operating voltage range, and the case in which the output levels of the decode signals f1t2x and f1t2z are "L" (Low) and "HI" (High), respectively, and the transfer gate 2a is selected, corresponds to the case in which the voltage level of the internal power source is regulated so as to attain the design target value described above.
The power source voltage levels that can be set to levels higher and lower than the design target value by two points, respectively, define the voltage range which can be trimmed by the selection of the level regulating resistors 57. When the operating voltage Vo of the internal power source VII becomes higher or lower than the operating voltage range due to a fluctuation of process conditions during the fabrication of the chip or the like, as shown in FIG. 1, the operating voltage can be regulated in the range of the voltage level covered by the above two points in both the upward and downward directions of the operating voltage level.
In order to illustrate the transfer gate which is selected by the internal power source control circuit 50, when the upper fuse or the lower fuse in each pair of fuses inside the fuse circuit 120 for trimming the internal power source are selectively cut off, FIG. 4 shows the relationship between a fuse selection and an output level in the prior art construction.
To select the five bit information described above, it is necessary to prepare a plurality of fuses corresponding to the number of fuses that is necessary for representing at least bit information of at least three bits (2.sup.3 =8). The fuse circuit 120 for trimming the internal power source described above can represent 3-bit (three-bit) information by using three pairs of fuses. When either one of the upper fuse and the lower fuse in each pair of fuses connected to the power source for the drain (here, the external power source VCC) and the power source for the source (here, the power source with the ground level VSS) is cut off, the decoding circuit 130 for fuse information of the internal power source is allowed to distinguish between "0" and "1", respectively.
In the fuse circuit 120 for trimming the internal power source, when the upper fuse is cut off, the node #k (here, k=0 to 2) is set to the voltage level of the power source for the source (approximately 0V) and the potential of this node #k is converted to a high logic level by the level converting circuit units 200 to 220. Therefore, the level of the output signal rff#k of the fuse circuit for trimming the internal power source changes to the level "H" (here, #=0 to 2; rff#x="H"). When the lower fuse is cut off, the node #k (here, k=0 to 2) is set to the voltage level of the power source for the drain (approximately Vcc), and the potential of this node #k is converted to a low logic level by the level converting circuit units 200 to 220. Therefore, the level of the output signal rff#x of the fuse circuit for trimming the internal power source changes to the level "L" (rff#x="L"). Furthermore, when the output signals rff0x to rff2x of the fuse circuit for trimming the internal power source sent from all the nodes #0 to #2 are decoded by the decoding circuit 130 for fuse information of the internal power source, the resistance values of the level regulating resistors 57 used in the internal power source control circuit 50, are decided.
Symbols 0x, 1x and 2x in FIG. 4 (or FIG. 3) represent #x of the output signals rff#x of the fuse circuit for trimming the internal power source, and also represent fuse information relating to the cut-off state of each of the fuses at all the nodes #0 to #2 on the fuse-cut side. In other words, these 0x, 1x and 2x represent the level of three inputs of a plurality of NAND gates for generating fuse information patterns for operating any one of the transfer gates 0a to 4a of the internal power source control circuit 50 shown in FIG. 3.
When the first transfer gate 0a disposed in the uppermost portion of these transfer gates 0a to 4a inside the internal power source control circuit 50 (FIG. 3) is desired to be selectively turned ON (i.e., to the operating state), for example, as shown in FIG. 4, the fuse for 0x in the NAND gate 330 for generating the fuse information, which is connected to this transfer gate 0a, is cut off so as to select the level "L", the fuse for 1x is also cut off so as to select the level "L", and the fuse for 2x, too, is cut off so as to select the level "L".
On the other hand, when the fifth transfer gate 4a of the lowermost portion of the transfer gates 0a to 4a inside the internal power source control circuit 50 is desired to be selectively turned ON, the fuse for 0x in the NAND gate 334 for generating the fuse information pattern, which is connected to this transfer gate 4a, is cut off so as to select the level "L", the fuse for 1x is also cut off so as to select the level "L" and only the fuse for 2x is cut off so as to select the level "H".
However, in the circuit having the function of regulating the voltage level of the internal power source according to the prior art described above, the fuse circuit such as the fuse circuit for trimming the internal power source is used in order to regulate this voltage level after the process for fabricating the chip is completed. Accordingly, this circuit involves the following problem.
A phenomenon referred to as a "glow-back" sometimes occurs in this circuit. The term "glow-back" hereby represents the phenomenon in which the fuse which should have been cut off by using a laser, etc., is not sufficiently cut off and remains in an incomplete cut-off state, or the phenomenon in which the fuse returns to the state before the cut-off state due to a stress caused by heat or voltage. Speaking electrically, this phenomenon means the case in which a resistance value of the portion which should attain a high resistance value after a cut-off of a given fuse changes to a low resistance value due to the glow-back (when the cut-off of the fuse is carried out insufficiently, the fuse remains in a low resistance value from the beginning).
When the voltage level of the internal power source has the design target value (i.e. default value) in the case of the fuse circuit for trimming the internal power source shown in FIG. 2, the fuse for 0x is cut off so as to select the level "L", the fuse for 1x is cut off so as to select the level "H" and the fuse for 2x is selected so as to select the level "L". In other words, the fuses at the nodes #0 to #2 inside the fuse circuit for trimming the internal power source may be cut off so as to select the level "L", "H" and "L", respectively. When such a process for cutting off fuses is carried out, the circuit operation is executed so that the third transfer gate 2a disposed in the central portion of the transfer gates 0a to 4a, for regulating the resistance value of the level regulating resistors 57 inside the internal power source control circuit 50, is selected.
On the other hand, the phenomenon brought about when a glow-back has occurred in the fuse circuit for trimming the internal power source will be considered.
The construction of this fuse circuit for trimming the internal power source is set so that the output signal rff#x of the fuse circuit for trimming the internal power source outputs the level "L" before the fuses are cut off. Therefore, the resistance value of the level regulating resistor 57 inside the internal power source control circuit 50, which is selected immediately after the completion of the process for fabricating the chip, is decided by the node connected to the first transfer gate 0a disposed in the uppermost portion of the transfer gates 0a to 4a.
Further, the fuses are cut off so as to attain an arbitrary value after the voltage level of the internal power source VII is measured. However, when all the fuses that are cut off undergo a glow-back, the node connected to the first transfer gate 0a is selected. In this case, a potential corresponding to a certain voltage level is supplied to this node through the transfer gate 0a and no critical problem occurs.
However, when only a certain fuse or only a portion of this fuse is in an incomplete cut-off state, and the pattern of bit information constituted by this incomplete cut-off state is a pattern other than the patterns of the five bit information described above, that is, when a given unnecessary pattern which is shown at the lower part of FIG. 4 and is not used at present is selected, all the transfer gates change to the OFF state (i.e., the non-operating state) and the overall circuitry inclusive of the fuse circuit 120 for trimming the internal power source, the decoding circuit 130 for fuse information of the internal power source and the internal power source control circuit 50 becomes unstable. In consequence, the problem occurs in that the semiconductor chip in which this circuit is formed carries out an abnormal operation.

Internal power source voltage trimming circuit


A dental colorimetry apparatus that allows the color balance of an entire row of teeth to be checked is provided. The invention provides a dental colorimetry apparatus 2 including a multiband-image storing section 21 storing images of teeth in association with information about the positions of the teeth in row of teeth; a contour-line extracting section 25 for extracting contour lines of the teeth from the images of the teeth; a rectangle-setting section 27 for setting rectangles in the images of the teeth so as to include the contour lines extracted by the contour-line extracting section 25 and so as to circumscribe at least both sides of the teeth; and an image-generating section 29 for generating a row-of-teeth image by arranging the images of the teeth based on the information about the positions of the teeth in the row of teeth so that the rectangles adjoin each other.

1. Field of the Invention
The present invention relates to dental colorimetry apparatuses, systems, and methods for colorimetry of patients' teeth and to computer-readable recording media storing dental colorimetry programs.
This application is based on Japanese Patent Application Nos. 2008-171438 and 2009-132244, the content of which is incorporated herein by reference.
2. Description of Related Art
Composite resins are conventionally used as dental fillers for filling cavities formed in teeth due to, for example, tooth decay. When filling a cavity with composite resins, for example, the dentist visually compares the color of the patient's tooth with those of color samples to select a color sample closest in color to the patient's tooth. Each color sample is provided with a table specifying a recommended combination of colors of composite resins used for filling. The dentist refers to the table corresponding to the selected color sample to select the colors of the composite resins used for filling before he or she performs treatment. The color samples are, for example, ceramic pieces with different colors manufactured in the shape of teeth.
In treatment using a ceramic crown, for example, the dentist visually compares the color of the patient's tooth with those of color samples, called shade guides, to select a color sample closest in color to the patient's tooth before he or she performs treatment using a prosthesis prepared based on the selected color sample.
The color samples are, for example, ceramic pieces with different colors manufactured in the shape of teeth.
On the other hand, to alleviate the burden on dentists associated with, for example, selection of a color sample, one proposed technique provides the function of automatically selecting a color sample closest in color to the tooth to aid dentists in selecting the color of a color sample (see, for example, Japanese Unexamined Patent Application, Publication No. 2007-190371).
According to Japanese Unexamined Patent Application, Publication No. 2007-190371, for example, the tooth to be treated and a color sample close in color to the tooth are displayed side by side on a display screen so that the dentist can check their colors etc. on the screen.


In order to accurately align an eye examining portion with the center of the pupil, (a) the interval d between illumination light source images PL and PR is an interval obtained when the operation distance has been properly position-aligned by other alignment means. (b) shows an interval d1 in a state in which the operation distance is longer than to a proper position, and (c) shows an interval d2 in a state in which the operation distance is shorter than the proper position. Even if the operation distance fluctuates when position alignment is effected with the center of the pupil, whereby the interval becomes d1 and d2 as shown in (b) and (c), a measuring portion is moved in front to rear direction and is made coincident with the reference interval d, as shown in (a), whereby a proper operation distance is obtained.

1. Field of the Invention
This invention relates to a suitable technique for an ophthalmologic apparatus which automatically effects the position alignment of an eye to be examined and the pupil center of an eye examining portion to thereby effect eye examination and photographing.
2. Related Background Art
As a conventional ophthalmologic apparatus for effecting auto alignment, there is known one which projects a light beam from within the measurement optical axis of an eye examining portion to the cornea of an eye to be examined, detects the reflected light thereof by a light receiving element, detects the positional displacement between the eye to be examined and the eye examining portion on the basis of the detected reflected image, and drives the eye examining portion to thereby effect auto alignment.
Also, as disclosed in Japanese Patent Application Laid-open No. H09-066027, there is known an apparatus which detects the pupil center and effects auto alignment in vertical and left to right directions, and as disclosed in Japanese Patent Application Laid-open No. H09-131314, there is known an apparatus which effects alignment detection in a front to rear direction by the interval of the cornea reflected image of an anterior ocular illumination light source.
In the aforedescribed conventional examples, when they are applied, for example, to an objective type eye refractive power measuring apparatus in which it is required to effect measurement at the center of the pupil, alignment detection in vertical and left to right directions is effected at the center of the pupil and alignment detection in a front to rear direction is effected by separating the cornea reflected light beam of alignment light, as disclosed in Japanese Patent Application Laid-open No. H09-84760.
If in this case, an alignment light source and a measurement light source are used in common, the range within which the reflected light of alignment light from the cornea of an eye to be examined can be detected by a light receiving element will become narrow because the light beam of the measurement light source is thin.
Regarding the alignment detection in the front to rear direction, as disclosed in Japanese Patent Application Laid-open No. H09-131314, there is a detecting method using the interval of the cornea reflected image of anterior ocular illumination, but in this method, the interval of the corneal reflected image of the anterior ocular illumination is varied by the radius of curvature of the cornea.


In an LCD driver, in a high voltage resistant MISFET, end portions of a gate electrode run onto electric field relaxing insulation regions. Wires to become source wires or drain wires are formed on an interlayer insulation film of the first layer over the high voltage resistant MISFET. At this moment, when a distance from an interface between a semiconductor substrate and a gate insulation film to an upper portion of the gate electrode is defined as “a”, and a distance from the upper portion of the gate electrode to an upper portion of the interlayer insulation film on which the wires are formed is defined as “b”, a relation of a>b is established. In such a high voltage resistant MISFET structured in this manner, the wires are arranged so as not to be overlapped planarly with the gate electrode of the high voltage resistant MISFET.

In Japanese Patent Application Laid-Open Publication No. 2005-116744 (Patent Document 1), a technology of forming a high voltage resistant transistor and a low voltage resistant transistor on a same substrate is described. In this Patent Document 1, it is said that the high voltage resistant transistor has an offset insulating layer for relaxing an electric field. A guard ring formed in the high voltage resistant transistor formation region is connected to a wire (a wire of the lowest layer) formed on an interlayer insulation film of the first layer. In contrast, a source region or a drain region of the high voltage resistant transistor is connected to a wire (not the wire of the lowest layer) formed on an interlayer insulation film of a second layer. In other words, the source region or the drain region of the high voltage resistant transistor is connected to a wire arranged on the interlayer insulation film of the second layer by a plug that penetrates both the interlayer insulation film of the first layer and the interlayer insulation film of the second layer at once.
In Japanese Patent Application Laid-Open Publication No. 4-171938 (Patent Document 2), a technology of forming a high voltage resistant n-channel FET and a low voltage resistant n-channel FET on a same substrate is described. In this Patent Document 2, in the low voltage resistant n-channel FET, a source region or a drain region thereof is connected to a wire of the lowest layer formed on an interlayer insulation film of the first layer. In contrast, in the high voltage resistant n-channel FET, a source region or a drain region thereof is connected to, not the wire of the lowest layer, but a wire formed on an interlayer insulation film of a second layer.

Semiconductor device and method of manufacturing the same


DNA constructs are provided for stable transformation of plastids of multicellular plants and expression of foreign proteins in plastids. The DNA constructs comprise a transforming DNA which is targeted to a pre-determined location on the plastid genome and inserted into the plastid genome by homologous recombination with targeting segments comprising DNA sequences homologous to the pre-determined region of the plastid genome. The transforming DNA contains a non-lethal selectable marker gene which confers a selectable phenotype on cells having plastids in which substantially all of the genomes therein contain the transforming DNA (i.e., homoplasmic cells or tissues). The transforming DNA further comprises at least one insertion site 4 for an additional DNA segment, such as a gene encoding a protein for improving a characteristic of the transformed plant. The non-lethal selectable marker gene is preferably provided as a chimeric gene by assembly from an expression cassette comprising 5' and 3' regulatory segments, preferably derived from plastid genes. A coding segment encoding the non-lethal selectable marker is inserted between the 5' and 3' regulatory segments to form the chimeric gene. The non-lethal selectable marker coding segment preferred in the present invention is the coding region of aadA from bacteria, which encodes aminoglycoside 3"-adenylyltransferase to confer spectinomycin and streptomycin resistance.

Transgenic plants are useful to study nuclear gene function and regulation and to improve agronomically important crop plants. Routine application of transgenic technology is made feasible by the alternative methods developed for transformation of nuclear genomes of higher plants. However, transgenic technology has not yet been applied to the genomes of the cytoplasmic organelles (i.e., plastids and mitochondria) of higher plants.
The size of plastid DNA (ptDNA) in higher plants is in the range of 120 kb to 160 kb (Palmer, Ann. Rev. Genet., 19: 325-54, 1985), and encodes the genes involved in plastid maintenance and photosynthesis. By now, three plastid genomes have been sequenced, including that of Nicotania tabacum (Shinozaki et al., EMBO J., 5: 2043-49, 1986). In addition to photosynthesis, plastids serve as a compartment for amino acid and lipid biosynthesis. Most if not all the genes involved in these functions are encoded by the nucleus. The enzymes encoded by nuclear genes are synthesized on cytoplasmic ribosomes, and are subsequently transported into the plastids. Expression and accumulation of nuclear gene products and of plastid gene products is coordinated (Gruissem, Cell, 56: 161-70, 1989).
Formation of stably transformed plastid genomes requires integration of the transforming DNA by recombination. That recombination is a mechanism contributing to the evolution of plastid genome is evident when comparing genomes of different plant species. Also, continued recombination through the plastid inverted repeat has been described (Palmer, 1985, supra). It has also been shown that intergenomic plastid recombination occurs in heteroplastidic cells obtained by protoplast fusion (Thanh & Medgyesy, Plant Mol. Biol. 12: 87-93, 1989), and is extensive (Fejes et al., Theor. App. Genet. 79: 28-32, 1990).
Introduction and stable integration of exogenous DNA has been reported recently in the plastid genome of a unicellular alga, Chlamydomonas reinhardtii (Boynton et al., Science 240: 1534-38, 1988; Blowers et al., Plant Cell 1: 123-32, 1989). Initial success in transforming the plastid genome of Chlamydomonas by Boynton et al. was made possible by the development of a microprojectile DNA delivery system based on a particle gun that delivers DNA-coated tungsten microprojectiles into the cell. In addition, a powerful selection scheme was applied that relied on complementing nonphotosynthetic deletion mutants. Subsequently, Blowers et al. showed that the Chlamydomonas plastid genome can be expanded by integrating the coding sequence of an E. coli enzyme, neomycin phosphotransferase. Transformation of the psbA gene encoding the D1 reaction center polypeptide of photosystem II, and of the 16s rRNA gene conferring resistance to streptomycin and spectinomycin was reported by Boynton et al., p.p. 509-16 in Current Research in Photosynthesis, M. Baltsheffsky, ed., 1990.
In higher plant chloroplasts, only transient expression of introduced DNA has been reported. DNA uptake and transient expression by isolated cucumber etioplasts of the large and small subunits of ribulose bisphosphate carboxylase/oxygenase of Anacystis nidulans, or of the E. coli enzyme, chloramphenicol acetyltransferase (CAT), has been reported (Daniell and McFadden, Proc. Natl. Acad. Sci. USA 84: 6349-53, 1987). The 5' end of the psbA (pea), and rbcL (maize) plastid genes were fused with the CAT gene. Transient expression of the constructs in chloroplasts of cultured tobacco cells has been reported by Daniell et al., Proc. Natl. Acad. Sci. USA 87: 88-92 (1990) after biolistic delivery. Some of the vectors contained replication origins from ptDNA. CAT activity was sustained longer when the replicon origins were present. CAT activity, however, was not shown to be localized in chloroplasts. CAT activity, therefore, could have been the result of expression in the nucleus, since plastid gene promoters are known to support transcription initiation in the nucleus (Cornelissen and Vandewiele, Nucleic Acids Res. 17: 19-28, 1989).
European Application No. 87305573.5, filed Jun. 23, 1987, by M. C. Cannon and F. C. Cannon, describes a method for producing a plant whose cells express a desired gene by inserting the desired gene into the plastid genome of a plant cell. However, this application does not suggest a method for stably transforming plastids using nonlethal selection, nor does it provide any evidence suggesting that stable transformation was, or could be, achieved.
Transformation of plastids in higher plants was claimed after Agrobacterium-mediated transformation of N. tabacum (DeBlock et al., EMBO J. 4: 1367-72, 1985). A CAT gene was engineered for expression in the nucleus, and transgenic clones were selected for resistance to 10 .mu.g/ml chloramphenicol. The authors claim that there was fortuitous integration of the CAT gene into the ptDNA and expression from a plastid promoter. The line was reportedly unstable, and the authors' claims have not been confirmed.
There are several differences between the Chlamydomonas system and higher plants that may be relevant for successful transformation of plastids. Two of these are discussed below. First, the number of plastids, and the number of plastid genomes per cell is much lower in Chlamydomonas than in Nicotiana. Chlamydomonas contains a single plastid, which carries up to 80 identical plastid genomes (Harris, The Chlamydomonas Sourcebook, p. 354, Academic Press, San Diego, 1989). In contrast, Nicotiana tabacum cells contain a variable number of plastids, about 100 in leaf cells, and 12 to 14 in meristematic cells and dedifferentiated tissue culture cells (Thomas & Rose, Planta 158: 329-38, 1983). In a study with cultured cells the number of plastid genome copies was estimated to be 3,000 to 12,000 per cell (Cannon et al., Plant Cell Reports 4: 41-45, 1985; Yasuda et al., Planta 174: 235-41, 1988).
Another important difference is that Chlamydomonas cells are grown photoautotrophically which allows stringent selection for photosynthetic ability, that is, functional plastids. This facilitates transformation by all proven methods, including Agrobacterium-mediated transformation (Weising et al., Ann. Rev. Genet. 22: 421-77, 1988), electroporation (Fromm et al., Nature 319: 791-93, 1986), calcium phosphate coprecipitation (Krens et al., Nature 296: 72-74, 1982), transformation by high-velocity microprojectiles (Klein et al., Proc. Natl. Acad. Sci. USA 85: 8502-05, 1988), and polyethylene glycol treatment (Negrutiu et al., Plant Mol. Biol. 8: 363-73, 1987). In contrast, higher plants are cultured photoheterotrophically, which reduces the stringency of selection for functional plastids.
Given the large number of plastid genomes in plant cells, the ability to select for the transformed genome in culture is a key element in achieving plastid transformation. Selection markers have been identified by screening culture plant cells for mutants resistant to various substances, such as antibiotics and herbicides. Since most of the selectable plastid genome markers have been developed through cell culture, it is not surprising that most are derived from Nicotania tabacum and Nicotiana plumbaginifolia, two species that are easy to grow in cell culture and to subsequently regenerate into plants. Resistance to inhibitors of plastid protein synthesis, conferred by mutation in the plastid 16S rRNA and 23S rRNA genes, are the most readily available markers. Other markers include resistance to streptomycin (Maliga et al., Nature 255: 401-02, 1973; Etzold et al., FEBS Lett. 219: 343-46, 1987; Fromm et al., Plant Mol. Biol. 12: 499-505, 1989), spectinomycin (Fromm et al., EMBO J. 6: 3233-37, 1987) and lincomycin (Cseplo & Maliga, Mol. Gen. Genet. 196: 407-12, 1984; Cseplo et al., Mol. Gen. Genet. 214: 295-99, 1988) which are the equivalent rRNA gene mutation used for transformation in Chlamydomonas (Harris et al., 1989, supra).
Plastid genome mutants resistant to triazine herbicides, have also been obtained in cultured Nicotiana cells. Triazine herbicides inhibit photosynthesis by interruption of electron flow at the acceptor of photosystem II. Selection was made feasible in Nicotiana cultures by lowering the concentration of sucrose in the medium, thereby making cellular proliferation partially dependent on photosynthesis (photomyxotrophic cultures; Cseplo et al., Mol. Gen. Genet. 200: 508-10, 1985; Sato et al., Mol. Gen. Genet. 214: 358-60, 1988). Selection for resistance to this class of herbicides is also a nonlethal color selection, resistant mutants being identified by their green color (Cseplo et al., 1985, supra). A mutation in two of the lines was localized to the psbA gene (Pay et al., Nucleic Acids Res. 16: 8176, 1988; Sato et al., 1988, supra). Similar mutants have been found in higher plants under field conditions (Maliga et al., p.p. 133-143 in Perspectives in Genetic and Biochemical Regulation of Photosynthesis, I. Zeitlich, ed., Alan R. Liss, N.Y., 1990), and isolated in Chlamydomonas (Erickson et al., Science 228: 204-07, 1985).
Naturally occurring resistance to tentoxin is also encoded on the plastic genome (Durbin & Uchytil, Biochem. Genet. 15: 1143-45, 1977). Pigment deficiency caused by plastome mutation is frequent, but does not appear to be a useful marker in culture. Pigment mutation in combination with antibiotic resistance mutations, however, have proved important in recovering a recombinant plastid genome (Medgyesy et al., Proc. Natl. Acad. Sci. USA 82: 6960-64, 1985).
The present invention provides a method for stable transformation of the plastids of higher plants. Others have attempted to obtain stable plastid transformation in higher plants, but without success. The present invention also provides efficient and versatile DNA constructs to accomplish stable transformation of plastid genomes and expression of foreign proteins in transformed plastids. These methods and constructs, heretofore unavailable, will enable improvement of useful plant species by genetic engineering of the plastid genome.

DNA constructs and methods for stably transforming plastids of multicellular plants and expressing recombinant proteins therein

Rutgers, The State University of New Jersey


In an example, operating a PLL circuit includes generating an error signal in response to comparison of a reference clock signal having a reference frequency and a feedback clock signal having a feedback frequency, generating a plurality of clock signals having an output frequency based on the error signal, and generating the feedback clock signal from the plurality of clock signals based on a first divider value and a control value derived from a second divider value. Operating the PLL circuit further includes multiplying each of a first integer value and a first fractional value by a power of two to generate a second integer value and a second fractional value, respectively, generating the second divider value using a sigma-delta modulator (SDM) based on the second integer value and the second fractional value, and dividing the second divider value by the power of two to generate the first divider value.

A frequency synthesizer, such as a phase-locked loop (PLL) can be used to provide a clock signal of a desired frequency. The PLL generates the clock signal based on a reference dock signal of a reference oscillator. An integer-N PLL is capable of generating a dock signal having a frequency that is an integer multiple of the reference frequency. A fractional-N PLL is capable of generating a clock signal having a frequency that is a non-integer multiple of the reference frequency. A fractional-N PLL is more flexible than an integer-N PLL due to its higher frequency resolution. Compared with an integer-N PLL, however, a fractional-N PLL can exhibit increased phase noise (jitter) due to generation of fractional boundary spurs ("fractional jitter"). To reduce fractional jitter, designers typically reduce the bandwidth of the fractional-N PLL. A greater ratio of the reference clock frequency to the PLL bandwidth leads to better jitter rejection. Such a reduction in PLL bandwidth, however, results in longer lock times and can cause excessive voltage controlled oscillator (VCO) phase noise to appear at the PLL output leading to higher random jitter. It is therefore desirable to reduce fractional jitter without the need to reduce PLL bandwidth.

Fractional-N phase-locked loop with reduced jitter


A despreader for generating one or more despread values corresponding to application of one or more despreading codes to a sequence of spread values comprises a data buffer, an adder, a subtractor, and a controller. The adder is adapted to generate a sum of a pair of values read from the data buffer. The subtractor is adapted to generate a difference of the pair of values read from the data buffer. The controller is adapted to control (1) reading of the pair of values from the data buffer and (2) writing of the sum and difference values into the data buffer. After each pair of spread values is stored in the data buffer, the despreader generates and stores one or more pairs of sum and difference values in the data buffer.

1. Field of the Invention
The present invention relates to wireless receivers, and, in particular, to a method for despreading bit sequences that have been spread with Orthogonal Variable Spreading Factor (OVSF) codes.
2. Description of the Related Art
When a signal travels through a real-world environment, it often reaches a receiver by multiple paths. These paths occur as a result of the signal reflecting, diffracting, and scattering from various elements in the environment, e.g., mountains, trees, and buildings. Multi-path components are essentially time-delayed variants of a single signal. While, in some applications, these multiple components may result in interference, e.g., ghosting on the display of an analog-television receiver, Code Division Multiple Access (CDMA) systems intentionally make use of these multiple components.
The basic principle of CDMA systems is orthogonal coding, whereby, instead of assigning specific frequencies or time slots to each user of a system, the users are distinguished from one another by assigning codes. The codes fulfill the same role as frequency or time in frequency- or time-division systems, i.e., to keep the signals for different users from interfering with one another. In orthogonal spreading, a symbol is XOR-multiplied by a defined bit sequence called a code. If the code length is N bits, then each symbol is transformed to N so-called chips. The resulting chip rate, i.e., the number of chips per second (e.g., bits per second), is N times the original symbol rate (number of symbols per second). For example, the spreading code 1111 has a length, also called a spreading factor (SF) or Orthogonal Variable Spreading Factor (OVSF), of four. A single 1 will be spread to the sequence 0000 (1 XOR'ed with 1 gives 0), and a single 0 will be spread to the sequence 1111. In general, codes are not arbitrarily chosen, but rather, selected according to certain mathematical rules that provide sets of codes that are orthogonal to each other. Orthogonal codes have no correlation. Consequently, signals spread with codes that are orthogonal to each other do not interfere with one another. For a single connection, input data is spread with a particular code at the transmitter end. To recover the data, the same orthogonal code is used at the receiver end to despread the signal.
High-Speed Downlink Packet Access (HSDPA) is a standard for high-speed data transfer methodology employed in the Third-Generation Partnership Project (3GPP) to support the increasing use of mobile data services, including enhanced data transfer rates. In an HSDPA system, a High-Speed Physical Downlink Shared Channel (HS-PDSCH) is sent from a base station to every user in a given cell, in addition to other channels that may be available as part of the existing 3GPP standard. The HS-PDSCH channel is itself split into a variable number of (up to 15) subchannels (hereinafter, "HS-PDSCH channels" or simply "channels"), whereby users are differentiated both by scrambling codes and by time allocation of the channels in 2 ms timeslots called Transmission Time Intervals (TTI). Each user is allocated a code to access an HS-PDSCH channel during the appropriate TTI, and each user has access to an accompanying High-Speed Shared Control Channel (HS-SCCH), which carries control information used by the user's mobile device to decode the current data in the HS-PDSCH. While the actual number of HS-PDSCH channels is determined by information carried the in HS-SCCH, the present application will refer, generally, to scenarios employing all 15 HS-PDSCH channels.
Each of the 15 HS-PDSCH channels is spread using a different OVSF code with a spreading factor of 16. The receiver in a mobile device despreads all 15 channels within every 16-chip period. The despreading of an HS-PDSCH channel is essentially an accumulation process involving either addition or subtraction of received chip data based on the unique OVSF bit sequence of the channel. Received HS-PDSCH data is despread to a symbol by adding or subtracting the corresponding OVSF codes during each 16-chip period. The order of adding or subtracting for a given HD-PDSCH channel is dictated by the OVSF code corresponding to the channel's OVSF code number. To comply with the 3GPP standard, a conventional HSDPA receiver simultaneously despreads 15 HS-PDSCH channels using physical instantiations of both an independent OVSF generator and an accumulator for each channel. Each of the OVSF generators either produces the OVSF bits on-the-fly or uses a look-up table to read the OVSF bits. During each 16-chip period, the OVSF generator provides the appropriate OVSF bits to the corresponding accumulator, which despreads the chips into a symbol. For each instantiation, as many as 15 addition or subtraction operations may be performed to despread a single symbol, for a total of up to 225 (15×15) operations per symbol. Accordingly, independently despreading each HS-PDSCH channel requires much hardware and consumes much power. The same inefficiencies occur in OVSF despreading applications outside the HSDPA standard, such as performing Walsh, Hadamard, and other pattern transforms, including those used in ordinary (i.e., non-3GPP) CDMA OVSF despreading.

Method and apparatus for compact OVSF despreading


An objective lens device having two light control surfaces and an optical pickup able to adopt disks having different thicknesses as a recording medium. The objective lens device includes an objective lens arranged along an optical path parallel to the disks, and first and second control portions formed in a light incident surface of the objective lens, a light emitting surface thereof, or an extra transparent member. Therefore, two disks having different thicknesses are compatible as a recording medium, and light interference occurring when using a thick disk can be decreased.

The present invention relates to an objective lens device which can be applied to a plurality of optical disks having different thicknesses, and to an optical pickup adopting the same.
Generally, an optical pickup of a compact disk player (CDP), a digital video disk player (DVDP), etc., is used to record and reproduce information on and from a recording medium in a non-contact manner.
Preferably, the optical pickup adopted in the DVDP which enables high-density recording and reproduction is applied to a recording medium such as a digital video disk (DVD), a compact disk (CD) or a CD-ROM for compatibility.
However, the standard thickness of the DVD is different from that of the CD or CD-ROM due to an allowance in the inclination of the disk and the numerical aperture of an objective lens. That is, since the thickness of the DVD is different from that of the CD, a spherical aberration occurs when an optical pickup for a DVD is applied to the CD. In this case, sufficient light intensity for recording an information signal cannot be obtained or a reproduced signal is deteriorated by the spherical aberration.
In order to solve the above problems, an objective lens device and an optical pickup adopting the objective lens device are proposed as follows.
In an objective lens device proposed by the applicants of the present invention, light of a middle region between a near axis region in which the spherical aberration occurring around the central optical axis does not occur and a far axis region surrounding the near axis region is blocked, an optical spot having a small peripheral light is formed without interference of light in the middle region.
As shown in FIGS. 1 and 2, a light control device is provided for blocking or scattering a light 122 of an incident light 120, incident on the middle region between the near axis region and the far axis region. Referring to FIG. 1, the light control device includes a transparent member 110 having a light control layer 111 for blocking or scattering the light incident on the middle region. In FIG. 2, the light control device includes a light control hole 111' formed in an objective lens 100', for scattering the light 122 incident on the middle region.
The near axis region is a region around the central axis of the lens (optical path), where negligible spherical aberration exists without influence on the central rays of the incident light 121. The far axis region is a region which is farther from the optical path than the near axis region and in which a light 123 is incident, thereby affecting the central rays. Also, the middle region is a region between the near axis region and the far axis region.
FIG. 3 is a schematic diagram showing an example of an optical pickup adopting the objective lens device shown in FIG. 1.
The optical pickup adopts the transparent member 110 having the light control layer 111 which was described with reference to FIG. 1. Thus, light emitted from a light source 150 passes through a beam splitter 140 and is then collimated by a collimating lens 130 to be incident on an objective lens 100 parallel to an optical path. At this stage, the light 122 incident on the middle region is blocked by the light control layer 111 formed on the transparent member 110, so that only the lights incident on the near axis region and the far axis region, respectively, pass through the objective lens 100. The lights 121 and 123 are converged by the objective lens 100 to form an optical spot on an optical disk 10. Thus, the objective lens device is compatible for a plurality of disks 10 having different thicknesses, such as a CD and a DVD.
Then, the light is reflected from the optical disk 10 and received by a photodetector 170 via the objective lens 100, the collimating lens 130 and the beam splitter 140. The photodetector 170 is composed of at least four divided plates which convert the received light into an electrical signal to be used as an error signal or information signal. At this stage, a condensing lens 160 is disposed between the beam splitter 140 and the photodetector 170.
FIG. 4 is a schematic diagram showing an example of the optical pickup adopting the objective lens device shown in FIG. 2.
The optical pickup adopts an objective lens 100' having a light control hole 111' for scattering the light 122 incident on the middle region. In this case, the elements designated by the same reference numerals as those of FIG. 3 and which are not described represent the same elements as those illustrated with reference to FIG. 3.
FIG. 5 is a graph showing an initial focus error of the optical pickup adopting a CD as a recording medium. The optical pickup includes an objective lens having a numerical aperture of 0.6 and a diameter of 4.04 mm, and the objective lens has an annular light control hole having an inner diameter of 1.2 mm and a width of 0.15 mm.
In FIG. 5, the X-axis represents the degree of defocus and the Y-axis represents a detected voltage value as an index of the degree of error.
Also in FIG. 5, there are two portions A and B, where the detected voltage values are zero. The portion A occurs when the optical pickup is placed in an "on focus" position to control an initial focus position. On the contrary, the portion B is occurs due to the spherical aberration caused by the difference in thickness of the recording media, and a waveform near the portion B, including the portion B, is defined as a parasitic waveform. The parasitic waveform exists because the focusing point of the beam which passed the far axis region is formed over a broad region by the spherical aberration of the objective lens.
When the parasitic waveform exists, the portion B may be considered as the "on focus" position due to the mechanical vibration of the recording medium.

Objective lens device including an objective lens and a transparent member having two light control portions and optical pickup using the objective lens device


A method of distributing workload in a workflow management system includes the step of calculating a load index for each engine of the workflow management system. The load index is calculated as an average activity execution delay attributable to the associated engine. The load indices indicate average execution latency between the start of consecutive activity nodes of a process due to engine loading exclusive of resource execution time. Workload is distributed across the plurality of engines in a load sensitive mode. In one embodiment, distribution switches from a load insensitive mode to a load sensitive mode for distributing processes when a maximum differential load index exceeds a first pre-determined threshold. Distribution switches from the load sensitive mode back to the load insensitive workload distribution mode for distributing processes when the maximum differential load index is less than a second pre-determined threshold.

Workflow management systems are used to monitor an organization's various administrative and production processes. These processes are defined in terms of activities, links, routing controls, resources, initiators, terminators, and the input and output process data.
For a given process instance, the workflow management system might record information about the activities performed, when these activities are performed, time used to perform the activity, the identity of any resources involved in the activities, the outcome, and other data related to execution of the activities. This information is recorded as log data to permit subsequent reporting. Through various reporting tools the information is summarized and provided to analysts, workflow design, system administrator or other entities.
Typical workflow management systems permit users to query the execution state of a running process, report the number of process instances started or completed within a given time period, or compute simple statistics about groups of instances of a given process.
The workflow management system should be scalable to accommodate growth or shrinkage of the volume of work. In order to achieve scalability, some form of load balancing is required. Although a round robin scheduling system may be used, such a scheduling approach balances workload evenly only in homogeneous workflow management systems with uniform workload and resource capabilities. Such an approach fails to equitably balance the load across a heterogeneous collection of workflow management systems having different resources and capabilities.

Method of load balancing a distributed workflow management system

Hewlett-Packard Development Company, L.P.


A memory device capable of performing a read operation includes: a memory array that stores data; and off-chip drivers that supply as an output of the memory device data retrieved from the memory array. At least one of the off-chip drivers includes: an enable circuit that generates an enable signal in response to a read enable signal received by the off-chip driver, wherein the enable circuit controls the timing of the enable signal in accordance with a timing signal supplied to the enable circuit; and a driver circuit that drives the data off the memory device in response to the enable signal.

1. Field of the Invention
The present invention relates to a memory device having off-chip drivers that include an enable circuit and related methods for reducing delays during read operations of the memory device.
2. Description of the Related Art
Attempts to minimize size and power consumption of electronic memory devices, such as dynamic random access memories (DRAMs), often lead to omitting certain components and features that may otherwise enhance memory device operation. Such considerations may be particularly important in applications where the memory device is incorporated into a battery-powered or mobile device. For example, some specialty memory devices, such as those used in mobile applications, may not feature any on-chip delay locked loops (DLLs), which are useful for aligning clocks and maintaining timing precision but tend to consume considerable power. Such a memory device can be, for example, a double data rate synchronous dynamic random access memory (DDR SDRAM), which is capable of reading out stored data in read bursts. With each read command, a read burst operation sequentially transmits a given number of data words from the memory device to the system in which the memory device is operating. A DDR SDRAM chip facilitates data transfers on both edges of each successive clock cycle (i.e., both the rising and falling edges), thereby doubling the memory chip data throughput. The data, conventionally denoted as "DQ," is driven off the chip via off-chip drivers (OCD).
Normally, an on-chip DLL aligns the read output to the external system clock (VCLK). Where the on-chip DLL is omitted for size or power considerations, any propagation delay of the internal clocking tree and logic after the last clocked stage before the output pad of the memory device data adds to the output delay (tAC) measured from the rising edge of VCLK. More specifically, the internal clock tree essentially derives various clock signals from the external VCLK signal, which are used to time a variety of operations on the memory device. However, the process of generating these internal clock signals and propagation delays across the chip result in timing offsets between the external VCLK signal and the various internal clock signals. Further, any logic circuitry that exists between the point of application of the internal clock signal and the output terminal contributes to the output delay tAC between the VCLK signal and the arrival of data at the output.
While some degree of output delay time tAC is acceptable, it is desirable to minimize the variability of tAC, such that the timing of data driven off memory chips is predictable and consistent from OCD to OCD, from chip to chip, and for each individual OCD over the operating time period of the system containing the memory devices, such that the variation of tAC remains within acceptable operational tolerances. Reducing the number of different delays that contribute to tAC tends to reduce the overall variability of tAC.
Moreover, the overall delay in retrieving stored data in response to a read command must be taken into consideration when designing memory devices. This timing "budget" may include a number of factors, including tAC. Thus, in general, reducing the value of tAC can either reduce the overall delay in retrieving data or can permit other delays that contribute to the overall delay to be increased without exceeding the overall timing budget. Further, reducing the value of tAC may permit greater timing flexibility in latching retrieved data at the OCDs, thereby providing greater leeway in the timing of the clock signal used to supply the data to the OCDs.

Memory device having off-chip driver enable circuit and method for reducing delays during read operations


A method and an apparatus for rigging up intervention equipment (111) in a lifting arrangement (104) utilized on a floating vessel, and moving the intervention equipment between an inoperative and an operative position, wherein the method comprising: a) providing the lifting arrangement (104) with vertically extending guiding means (203) capable of transferring a load to the lifting arrangement; b) connecting a load transferring means (215) to the guiding means (203); c) connecting the intervention equipment (111) to a load carrying device (209) provided with displacement means (214) arranged in a manner allowing a load to be horizontally displaced while carried by the load carrying device; d) connecting the load carrying device (209) to the load transferring means (215); e) moving the intervention equipment from an inactive position to an operating position by moving the displacement means (214); and f) moving the intervention equipment from the operating position to the inactive position by moving the displacement means (214).

The disclosure regards a system and a method capable of functioning as an apparatus for transport and handling of equipment in a lifting arrangement used on a floating vessel. More precisely, the disclosure regards a method and an apparatus for rigging up intervention equipment in a lifting arrangement utilized on a floating vessel, and moving the intervention equipment between an inoperative and an operative position.
Offshore subsea wells are typically developed using floating vessels to accommodate equipment, personnel, and operations necessary to drill and complete a well in order to initiate production of hydrocarbons from a given reservoir forming the target for the well. Additionally, testing and intervention work is typically executed through the use of such floating vessels. It is to be understood, however, that such a floating vessel also could be used in context of other types of subsea wells, for example water or gas injection wells.
It is understood that a floating vessel will be subjected to vertical and horizontal (pitch and roll) movement due to the action of the natural environment such as wind and the waves of the sea (or a lake), which in turn introduces a challenge with respect to equipment utilized during operations carried out on the floating vessel. Such operations may include, but are not limited to drilling, completion, well testing, and well intervention. During operation at sea, said equipment will be subjected to vertical movement unless compensated for such movement.
As a floating vessel moves up and down in response to the waves, e.g. a drill string and a drill bit extending down below the vessel from a load-bearing structure, such as a top drive located within a drilling rig, will also move up and down. As it is essential that the weight on the drill bit, i.e. the downward force applied to the bit, is kept as constant as possible, such up and down movements of the drill bit are undesirable and provide for inefficient drilling progress which is counterproductive. Heave will remove weight from the drill bit as the rig moves up in conjunction with the high crest of a wave, while weight will be added to the drill bit as the rig moves down into the low point between two waves. Should hydrocarbons start to flow from a reservoir and into a wellbore being drilled, a valve arrangement is utilized to prevent such hydrocarbons from discharging into the natural environment and onto the floating drilling vessel. Such a valve arrangement is commonly referred to as a Blow Out Preventer (BOP), which is capable of sealing around, or cutting and sealing above, a drill pipe cut by shear rams in the BOP.
In other operations, which may include well testing and well intervention, e.g. wireline operations and coiled tubing operations, several sections of a high pressure tubular, commonly referred to as workover riser, are connected between equipment located at the seafloor, such as a subsea wellhead or a subsea Christmas tree, and the floating drilling vessel. The workover riser provides a barrier element for allowing control of pressurized hydrocarbon fluids present in the reservoir, and hence in the wellbore. A subsea valve arrangement, such as a subsea BOP, is also utilized in such operations to provide a system capable of sealing the well in case of an uncontrolled discharge of hydrocarbons from the reservoir. During such operations, hydrocarbon fluids may be present throughout the wellbore and the workover riser, and discharge at surface rig level is typically prevented by means of a valve arrangement located at the surface, commonly referred to as a surface flow tree. A surface flow tree, or similar equipment attached to a workover riser, extending upwards from equipment located on the seafloor to the rig, is usually supported by, and kept in tension by, the top drive and drawworks forming part of the drilling rig on a floating drilling vessel. Various types of lifting arrangements are utilized to connect the surface flow tree to the top drive and to hold the workover riser in tension as required to prevent high loads from acting on the equipment on the seafloor. Such lifting arrangements may include, but are not limited to, rigid bails, tension frames, soft slings, and backup heave compensation systems. A backup heave compensation system is disclosed in U.S. provisional application Ser. No. 61/480,239 and is referenced herein for informative purposes.
Well completion involves the use of production tubulars, which typically extend downwards from the wellhead and the Christmas tree to the producing zones bound by the reservoir(s) targeted by the well(s). Some parts of a completion operation will require equipment to be in tension in a manner similar to that described above. This may comprise setting the upper lock and seal mechanism of the production tubular, commonly referred to as a tubing hanger, inside the well-head. At this point, a landing string, which is typically made up of several sections of tubular, such as drill pipe or workover riser, will be connected to said tubing hanger at the wellhead and to the top drive at the floating drilling vessel via said lifting equipment. Similar to the description above, the weight of the system is controlled by holding said landing string in tension, thereby maintaining a known force at the level of said tubing hanger.
In operations requiring coiled tubing it is necessary, as mentioned above, to utilize a lifting arrangement capable of maintaining tension in the tubular extending from the wellhead to the floating vessel, such as a workover riser system, to prevent high loads from acting on the equipment on the seafloor. The lifting arrangement must be of a size such that coiled tubing equipment, such as a coiled tubing BOP, coiled tubing dual stripper arrangement and coiled tubing injector head, can be fitted and supported within the lifting arrangement. Furthermore, it is beneficial and in some instances a requirement that the coiled tubing equipment is transported to and from the lifting arrangement by means of lifting devices such as winches and/or hoists integrated in the lifting arrangement. Based on this, it is common practice to utilize tension frames with integrated lifting devices to accommodate for coiled tubing equipment required to execute said operations. The complexity of such tension frames are continuously evolving with respect to functionality integrated in such frames. Such functionality may include but is not limited to lifting devices, such as winches and hoists, manipulator devices utilized to guide equipment being lifted, advanced platform devices comprising means for vertical and horizontal adjustment of equipment such as the coiled tubing injector head, and adjustable work platform devices to accommodate for risk reducing measures during operational sequences and maintenance of equipment. Additional functionality is not merely advantageous as complexity and weight increases, and in some situations limits overall applicability of a tension frame due to said complexity and amount and severity of handling operations required to rig up the tension frame and furthermore change from one mode to another, such as to change from a coiled tubing mode to a wireline mode. Additionally, complex and time consuming operations are required onshore to prepare such tension frames for coiled tubing mode. In situations requiring coiled tubing capability on a floating vessel it is normally, as a minimum, required to utilize wireline equipment prior and after the coiled tubing intervention, hence it is required to alternate between wireline and coiled tubing modes several times. Based on this, it is commonly understood that the added functionality described above introduces disadvantages and increases the risk to personnel and equipment during intervention operations executed by means of tension frames, coiled tubing equipment, and wireline equipment.
In accordance with prior art intervention operations, such as for wireline and coiled tubing operations are executed by means of an intervention frame, such as a coiled tubing tension frame. The tension frame is utilized as a lifting arrangement connected to a load bearing unit in top, such as a top drive, and a surface valve arrangement in bottom, such as a surface flow tree or wireline adapter, further connected to a tubular, such as a workover riser or drilling tubular, extending from the floating vessel to equipment located on the seafloor. Hence, the tension frame and top drive is organized in a manner to hold the weight of said surface flow tree and said tubular, and furthermore ensure that the tubular is in tension to prevent high loads from acting on the equipment on the seafloor. In early configurations of such tension frames, it was common that one lifting device, such as a winch or hoist, was included in a top load bearing member, such as a beam, of the tension frame, which in turn was utilized to lift intervention devices, such as coiled tubing BOP and injector head, from a deck to the tension frame and landed onto a tubular member, such as a x-over/adapter, extending from a said surface flow tree or wireline adapter into the tension frame and also in reverse order in conjunction with removing the coiled tubing equipment from the workover riser stack and tension frame to be landed back onto the deck. The x-over/adapter extending from said surface flow tree or wireline adapter is commonly utilized as the mechanical interface towards a lower load bearing member, such as a beam arranged with such an mechanical interface, of the tension frame such that all forces are maintained by this said mechanical interface.
During recent years several intervention frame concepts have evolved, comprising more advanced functionality related to handling of intervention devices, such as coiled tubing BOP and injector head. These more advanced tension frames typically comprise two or more handling winches/hoists attached to a top load bearing member, such as a top beam, an injector head handling apparatus, such as a platform apparatus, attached to at least two parallel guides, such as tension frame legs, forming a substantially vertical tensioning frame, a manipulator device, adjustable work platform devices, and a lower load bearing member, such as a beam, with an integrated mechanical interface towards a tubular such as a x-over/adapter, extending from a said surface flow tree or wireline adapter into the tension frame. The winches/hoists are typically split into various categories with respect to rated specifications, where a large version winch/hoist is utilized to lift the coiled tubing BOP and injector head into/out of the frame during rigging, while smaller winches/hoists are utilized to handle and rig up smaller equipment such as devices dedicated for purposes of the work in a well, such as bottom hole assemblies used for the actual operation in a well. The platform apparatus defines a landing point for a coiled tubing injector during rigup, whereupon after landing the injector head is moved horizontally and vertically by means of functionality part of the platform apparatus and/or said tension frame. The manipulator device is included to function as a guide to prevent loads hanging from winches/hoists from moving during handling. Adjustable work platforms are included to ensure safe working areas for personnel during operation and maintenance of equipment that is part of the intervention operation executed by means of the intervention frame and intervention devices described herein.
Despite of having some advantages, the recent technological evolvements related to coiled tubing tension frames introduce several disadvantages. The platform apparatus mentioned above requires hydraulic and/or mechanical systems to enable horizontal and vertical movement from a remote location. This functionality comprises several moving and fixed devices which add weight and complexity to the total system during handling, and additional control functions and related hydraulic conduits and/or electric conduits must be part of the tension frame during handling. Additionally, since the platform apparatus is a part of the tension frame prior to lifting intervention devices, such as a coiled tubing injector head, it is necessary to lift the injector head to a certain height prior to moving the load towards center to ensure clearance between the injector head and said platform apparatus prior to landing the injector head onto the platform apparatus, which in turn impose a large working angle onto the winch/hoist wire/chain during handling. Furthermore, the platform apparatus introduces a large sized piece of equipment which is not required for other intervention operations to be executed, such as wireline work, such that it would be beneficial to remove the platform apparatus prior to executing said wireline operations. However, due to the complexity involved with removing the platform apparatus from the tension frame in a rigged up and hence operational position, it is common to leave this as part of the tension frame during said wireline operations further implying non-optimal working environment during said wirleline operations.
It is commonly accepted that weight and complexity of an intervention frame should be limited to a minimum during handling to reduce risk of failure and consequences related to potential accidental situations.
GB 2 418 684 B discloses an apparatus and a method for protecting against problems associated with handling a coiled tubing injector head within a coiled tubing tension frame. The publication discloses a platform apparatus adapted for connection with an intervention frame, the platform apparatus comprising a supporting member, such that in use, the platform apparatus is connected to the intervention frame and the supporting member is shaped or otherwise adapted to support an intervention tool such as a coiled tubing injector. Thus, it is possible to stow an injector head on the intervention frame during use of the frame for other purposes, such as wireline. The publication further specifies that this apparatus and method will significantly reduce the amount of time required for changeover from coiled tubing intervention to wireline intervention. The publication further specifies that in preferred embodiments, the platform apparatus is rotatably connected to the frame and also comprises a turntable. Preferably the platform apparatus can rotate around the frame in a first direction whilst the turntable apparatus rotates in the opposite direction thus maintaining the direction of any coiled tubing towards a V-door provided in the derrick, regardless of the rotational position of the platform apparatus. The invention describes a method for handling a coiled tubing injector head inside an intervention frame, which in turn can be rotated to the side of the intervention frame to create free space for a wireline operation. However, one skilled in the art will recognize disadvantages and operational limitations as it is disadvantageous to position a large load, as represented by a coiled tubing injector head, on the side of an intervention frame structure, as this will generate an uneven force distribution and related bending moments in an intervention frame subjected to movements as generated by movements of the floating drilling vessel as inflicted by the natural environment. Furthermore, the disclosed apparatus illustrates a system where the platform apparatus is mounted as a part of the intervention frame prior to lifting the injector head, further meaning that it is necessary to lift the injector head to a certain height prior to moving the load towards center to ensure clearance between the injector head and platform apparatus prior to landing the injector head onto the platform apparatus, which in turn impose a large working angle onto the winch/hoist wire/chain used during handling.
Further, NO 322006 (B1)/U.S. Pat. No. 7,306,404 B2 also describes a platform apparatus being part of a handling device for well intervention on a floating vessel. The publications disclose a handling device for well intervention, the handling device being releasably connected, in an operative position, to a riser and to a heave compensator which is arranged to maintain a prescribed tensioning of the riser. The handling device comprising: a lower riser securing device; a substantially vertical tensioning frame provided with at least two parallel guides; a jacking table provided with an upper riser securing device; at least one tension-resistant connection between the tensioning frame and the heave compensator located there-above; the jacking table being movable connected to the at least two parallel guides, at least one of the at least two parallel guides including lifting screws for moving the jacking table along the guides in their, in the position of use, vertical extent, and the jacking table including hydraulic cylinders for moving the upper riser securing device in a horizontal direction along at least one axis of movement. One skilled in the art will recognize that the disclosure describes an intervention frame, such as a tension frame, with a moveable jacking table comprising a device and method for clamping onto a tubular, such as a riser, to function as a method for rigging tubular riser sections within the intervention frame, by means of vertical and horizontal displacement of the jacking table. One skilled in the art will furthermore recognize that the jacking table may function as a landing platform for a coiled tubing injector head, and furthermore provide means for handling said injector head in both vertical and horizontal directions. However, in the same manner as explained for the disclosed publication GB 2 418 684 B, the disclosed apparatus and method in publications NO 322006 (B1)/U.S. Pat. No. 7,306,404 B2 describes a system where the platform apparatus, by means of the jacking table, is mounted as a part of the intervention frame prior to lifting the injector head, further meaning that it is necessary to lift the injector head to a certain height prior to moving the load towards center to ensure clearance between the injector head and platform apparatus prior to landing the injector head onto the platform apparatus, which in turn impose a large working angle onto the winch/hoist wire/chain used during handling.

Method and an apparatus for rigging up intervention equipment in a lifting arrangement utilized on a floating vessel


The present invention provides for a lottery pooling management system. The lottery pooling management system may include a participant interface, lottery interface, and notification interface. The participant interface may be in communication with a participant computer and configured to allow pool participants to participate in one or more lottery pools with each lottery pool having one or more sets of lottery numbers. The lottery interface may be in communication with one or more lotteries and the participant interface, and configured to ascertain drawing results and jackpot amounts for the lotteries and compare the drawing results with the sets of lottery numbers in the lottery pools. The notification interface may be in communication with the participant interface and the lottery interface, and configured to alert pool participants about activity in the lotteries, the status of the lottery pools, and the compared drawing results.

Government sponsored lotteries have gained awesome popularity throughout the world. Lotteries have evolved from a deep history that touches the very beginnings of North America dating back to King James I of England who, by royal decree, created a lottery in London. The proceeds were to be used to aid the first British colony in America—Jamestown, Va. In 1964, the New Hampshire Legislature created the first legal state lottery in United States History. By 1973, fiscal year sales for all lotteries surpassed $500 million. In 1976, lottery sales surpassed $1 billion for the first time. By 1998, the Multi-State Lottery Association recorded a world-record lottery jackpot of $295.7 million for its Powerball game. In 1999, Maria Grasso of Boston won a lump sum prize of $104 million in "The Big Game," the largest prize ever won by a single individual. By 1999, thirty-seven states and the District of Columbia operated a lottery in the U.S., along with legal lotteries in Canada. More than 100 foreign lotteries exist today and many have operated for centuries. Some countries, like Mexico, France and Japan, for example, have national lotteries. The International Association of State Lotteries lists 63 member nations—one on every continent except Antarctica.
Lotteries have benefited from the employment of technological advances over the last three decades of the 20th century. In 1971, the world's first on-line system was deployed in New Jersey. In 1973, the first secure instant ticket system was developed. In 1974, Massachusetts offered the first scratch-off lottery ticket. In 1975, New Jersey introduced a statewide, on-line network of several hundred Clerk Activated Terminals (CATs) implemented by General Instrument. In 1985, "Tri-State Lotto," the first multi-state lottery, linked the state lotteries of Maine, New Hampshire and Vermont. In 1991, the Virginia Lottery awarded the first instant ticket vending machine contract. In 1986, the Illinois Lottery introduced the first instant game with the concept of qualifying "entry" tickets for a grand prize drawing. With the advent of the World Wide Web and the Internet, electronic Internet Websites have recently been created to provide lottery players with news and statistical information related to lotteries.
With regard to lottery gaming techniques, it is becoming popular to enter into lottery pools in order to increase one's chances of winning the lottery. With a lottery pool, individuals generally get several lottery tickets together to create a larger pool of potentially winning numbers for a group. Generally the burden of collecting tickets, tracking names, and distributing photocopies of the tickets is born by an individual in the group. After the drawing, the pool must be checked against the winning pick. This can quickly become quite time consuming as a winning combination may be a match of three, four, five or six numbers (in a pick six lottery for example). Powerball can be even more difficult to manage. Winning combinations can potentially be overlooked because of manual intervention, which may result in millions of dollars in unclaimed winnings every year.
Therefore a need has arisen in the lottery gaming industry for systems, methods, and apparatuses for managing lottery pools, over global communications networks.

System, methods and apparatuses for lottery pool management


When a user views a three-dimensional video on an external apparatus, the user cannot always simultaneously view the three-dimensional video on another video display apparatus, because of the difference between the display methods used by these apparatuses, for example. In such case, when a three-dimensional video signal is output to the external apparatus, a display unit of the video display apparatus displays a two-dimensional video. In this way, even when the external apparatus is displaying a three-dimensional video, a user can simultaneously view the display unit of the video display apparatus easily.

1. Field of the Invention
The claimed invention generally relates to displays and, more particularly, to a display apparatus capable of displaying a three-dimensional video signal on a display unit.
2. Description of the Related Art
Recently, various types of three-dimensional video display apparatuses, which can enable a user to recognize a two-dimensional video as a three-dimensional video by utilizing optical illusions based on parallax, have been discussed. As a method of displaying a three-dimensional video, an active shutter method is known. In the active shutter method, a viewer wears glasses having shutters, and a video for the right eye and a video for the left eye are alternately displayed. The shutters are controlled so that the eyes can view only the respective videos. As another method of displaying a three-dimensional video, a polarization method is also known. In the polarization method, a right-eye video and a left-eye video are alternately displayed on every other line on a display, and the lines displaying the right-eye video and to the lines displaying the left-eye video are differently polarized. The glasses are also polarized correspondingly. In this way, each of the right and left eyes recognizes a different video. There is also a method utilizing spectroscopy instead of polarization. In addition, as a method of enabling a user to view a three-dimensional video with naked eyes, a parallax barrier method is known. In the parallax barrier method, a slit barrier is provided on the front side of the display, and each of the right and left eyes recognizes a different video. In addition, a lenticular method is also known. In the lenticular method, many minute lenses are provided on the front side of the display, and each of the right and left eyes recognizes a different video.
In addition, display apparatuses capable of displaying both two-dimensional videos and three-dimensional videos are also known.
For example, Japanese Patent Application Laid-Open No. 2004-109330 discusses a mobile phone including a display unit capable of displaying a three-dimensional image. The mobile phone switches a three-dimensional image display screen to a two-dimensional image display screen according to a key operation other than number keys including # and * keys, a call key, a mail key, and a camera key.
However, an issue remains with these display apparatuses capable of displaying both two-dimensional and three-dimensional videos. For example, when a display apparatus outputs a three-dimensional video signal to an external apparatus, if the display apparatus and the external apparatus use different three-dimensional video display methods, a user cannot simultaneously and accurately view a three-dimensional video displayed by the display apparatus and the external apparatus. This is inconvenient when, for example, the user alternately executes an operation of a personal computer (PC) capable of displaying a three-dimensional video and a check of a video displayed on a large-screen television (TV) connected to the PC. According to the above described conventional technique, a user key operation is used as a trigger to switch the two-dimensional display and the three-dimensional display. However, if a user needs to simultaneously view or alternately check a video displayed on a plurality of display apparatuses capable of displaying three-dimensional videos, it is troublesome to operate each of the display apparatuses.

Display apparatus and method of controlling the same for displaying a three-dimensional video


A memory architecture for a regular array of non-volatile ferromagnetic rom access annular memory elements which can be based on the giant magnetoresistance (GMR) effect. A first sense row in the array connects the memory elements with strips which are staggered so that each memory element is connected through its upper surface to the memory element on one side and through the lower surface to one on the other side. Running transverse to the first sense row is a word line made up of a series of wires passing in magnetic field producing proximity to the memory elements along a column of the array and not being in electrical contact with the memory elements. The strips of the word line are staggered so they similarly produce a meandering conductive pathway through the word line from one side of the array to the other in series. The wires of the word line can pass through the open core of the annular element or the wires can pass adjacent to the memory elements. A third addressing mechanism in the form of an additional bit line provides added flexibility for the magnetic switching. The bit line is arranged parallel to the sense row and the strips of the bit line are again staggered so that each wire is connected through its top contact to the wire on one side and through its bottom contact to the wire on the other side. This bit line can be used in combination with or in place of the sense row for magnetic switching when it is further used in combination with the word line. Magnetic switching can be done by the word line and the bit line without using the sense line current. In a further embodiment the memory element has an insulative nonmagnetic memory layer so the memory element becomes a magnetic tunnel junction.

1. Field of the Invention
This invention relates to ferromagnetic memory and more specifically to ferromagnetic memory utilizing giant magnetoresistance and spin polarization in annular memory elements.
2. Description of the Related Art
In U.S. Pat. No. 5,541,868 an annular GMR-based memory element is disclosed. The description tells how to construct a magnetic memory element using the giant magnetoresistance effect with the current passing perpendicular to the plane of the device. The disclosure does not, however, describe an optimal circuit architecture employing those elements, nor does it discuss how many different approaches to reading and writing may be realized by employing different supporting circuits.
3. Objects of the Invention
It is an object of this invention to provide a magnetic random access memory which is scalable to greater than 1 gigabit/cm.sup.2 density.
It is a further object of this invention to provide a magnetic random access memory which has fast switching elements which are capable of switching at less than 10 nanoseconds.
It is a further object of this invention to provide a magnetic random access memory which has a wide temperature tolerance of from -150.degree. C. to +150.degree. C.
It is a further object of this invention to provide a magnetic random access memory which can be made by a low cost fabrication technique such as sputtered metal films on silicon.
It is a further object of this invention to provide a magnetic random access memory with a bit line in addition to a sense line and a word line to add flexibility to the magnetic switching and bit addressability.
It is a further object of this invention to provide a magnetic random access memory which has a bit line in addition to a sense line and a word line so that the current through the sense line is not needed for manipulating the magnetic state of the memory element.
These and further objects of the invention will become apparent as the description of the invention proceeds.

Read/write memory architecture employing closed ring elements

The United States of America as represented by the Secretary of the Navy


Provided is a work plan verification device capable of improving work efficiency of movement work of a suspension load. The work plan verification device determines whether an operator indicates a movement position of the suspension load on an image (A) displayed on a monitor (30). When a determination is made that the movement position is indicated, a mark is displayed on the movement position (B). Subsequently, a determination is made that the suspension load is suspended on a boom. When the determination is made that the suspension load is suspended, a load factor (C1) which is moving determination information allowing an operator to determine whether the suspension load can be moved to the movement position (B) is calculated, and the calculated load factor is displayed on the image (A).

A conventional crane includes a boom to move a suspension load. The boom is telescopically formed and horizontally turnably and derrickably provided on a vehicle body.
A hook block is attached to a tip end of the boom through a wire. A hook is attached to a lower end of the hook block. The suspension load is hooked to the hook to be suspended.
A crane discloses a method of displaying a three-dimensional position of the suspension load (see Patent Literature 1). Another crane discloses a method of performing an operation of the crane by indication using a touch panel (see Patent Literature 2).


This invention concerns a module for insertion into an additive manufacturing apparatus. The module comprising a frame mountable in a fixed position in the additive manufacturing apparatus, the frame defining a build chamber and a dosing chamber. A build platform is movable in the build chamber for supporting a powder bed during additive manufacturing of a part. A dosing piston is movable in the dosing chamber to push powder from the dosing chamber. A mechanism mechanically links the build platform to the dosing piston such that downward movement of the build platform in the build chamber results in upward movement of the dosing piston in the dosing chamber.

Selective laser melting (SLM) and selective laser sintering (SLS) apparatus produce objects through layer-by-layer solidification of a material, such as a metal powder material, using a high energy beam, such as a laser beam. A powder layer is formed across a powder bed in a build chamber by depositing a heap of powder adjacent to the powder bed and spreading the heap of powder with a wiper across the powder bed. A laser beam is then scanned across areas of the powder layer that correspond to a cross-section of the object being constructed. The laser beam melts or sinters the powder to form a solidified layer. After selective solidification of a layer, the powder bed is lowered by a thickness of the newly solidified layer and a further layer of powder is spread over the surface and solidified, as required. An example of such a device is disclosed in U.S. Pat. No. 6,042,774.
A build volume is defined by the walls of the build chamber and the extent to which a build platform, supporting the powder bed, can be lowered into the build chamber. In certain circumstances, it may be desirable to change the size of the build volume. For example, when manufacturing small parts and/or manufacturing parts from expensive materials, such as gold, it may be desirable to reduce the build volume to reduce the time for the build and/or the amount of powder material that is required.
US2011/0278773 discloses a method of reducing the build volume comprising building walls for confining the powder to a smaller volume at the same time as building the part. An application device for applying powder layers is provided with an insert to reduce the working filed across which powder is applied.
DE102009020987 discloses a volume reducing element that can be inserted into the build chamber to reduce the volume available for the build. A subcarrier is also provided for supporting the powder bed, the subcarrier including a connector plate for connecting the subcarrier to the main support piston movable in the build chamber. A cover may be provided in a piston operated doser to reduce the volume of powder required to fill a supply chamber.
US2011/0252618, WO2013/189617 and EP2732890 also disclose arrangements in which elements are inserted in to a build chamber to reduce the available build volume.

Module for additive manufacturing apparatus