Abstract: A modified asphalt Contactor reactor for blending and reacting asphalt cement and modifiers is described; for example, a vertically oriented vessel having an outer shell having an internal surface and an external surface, a lower end and a flat flanged top; an internal circulation tube having a base, a top and an outside surface, wherein the outside surface of the internal circulation tube and the internal surface of the outer shell forms an annulus; a heating jacket having heating oil inlet and a heating oil outlet coupled to the external surface of the outer shell for circulation of heating oil; and a hydraulic head assembly having an impeller coupled to the lower end the vertically oriented vessel wherein the impeller is located near the base of the internal circulation tube, wherein the impeller and the annulus are of sufficient size to facilitate the flow of high viscosity fluids.

Abstract: A mixing head includes a mixing device which is secured to a housing and has a mixing chamber for mixing at least two plastic components to form a material mixture. Received in a recess of the housing is a cleaning device which has a cleaning piston for back-and-forth movement in relation to the mixing chamber between a first position in which the cleaning piston is retracted from the mixing chamber and a second position in which the cleaning piston extends into the mixing chamber. The cleaning device has a barrier which interacts with a housing wall for pushing the material mixture radially outside. The barrier has a flank which has an incline which is steeper than an incline of the housing wall.

Abstract: A powered test-tube agitation device (10) includes a small plate (12) having a rest (13) for a test tube (14) to be agitated and operated in agitation by a powered mechanism (15). The powered mechanism (15) is started by means (17, 117) of optical detection of the entry of an object into a predetermined zone above the small plate. Advantageously the detection means are photoelectric infrared reflection detection means (17).

Abstract: An embodiment of a mixer for mixing a powder with a liquid comprises a mix housing to accommodate a mixture of the powder and the liquid, a liquid delivery housing coupled to the mix housing to provide the liquid thereto, and a powder delivery housing coupled to the mix housing to provide the powder thereto, wherein the mixer is configured to induce a vibration therein for substantially avoid an occluding cake build-up of the mixture thereat.

Abstract: A cordless kitchen appliance (10) comprising a power unit (12), a detachable blade extension unit (14) and a base module (60); said power unit and said detachable extension unit adapted for retention in said base module when not in use; said detachable extension unit provided at a distal end with an open cage; said open cage (34) shrouding a blade assembly (52).

Abstract: Method for preparing a silicate-based foam by mixing the silicate anti a pressurized carrier gas, characterized in that an accelerator, which causes the silicate to harden by chemical reaction, is added to the silicate. The accelerator can be selected from acids and acid-forming substances. While retaining the good properties and possible applications of the foam prepared in accordance with the prior art, this foam is improved by preparing a solid foam, i.e. a foam which remains foam after drying. This solid foam, inherently, i.e. without any reinforcing agent or filler, has a good dimensional stability. Devices for applying the method, an aerosol can in which the method is applied, and a prepared foam product.

Abstract: An apparatus for preparing samples of granulated material comprises an upper vessel having a floor including a plurality of planks, slots between each plank, and an open ceiling to allow passing of homogenized material, a lower vessel under the upper vessel and having a plurality of division plates that fit in the slots and form a plurality of compartments which hold samples, a feeder which oscillates over the upper surface of the upper vessel to render a homogenised and representative sample. The method comprises positioning the lower vessel under the upper vessel, feeding material to be sampled through the feeder by an oscillating movement, raising the lower vessel such that the division plates partition the heap of material to form a plurality of samples, removing planks from the upper vessel, thus forcing the plurality of samples to fall toward the compartments, and separating both the vessels to remove the samples.

Abstract: A device (100) for manufacturing ready-to-use knifing filler for spackling surfaces, in particular of motor vehicle bodies, by mixing a binder component and a hardener component to a pasty or fluid mixing material using a mixing device (1) consisting of a hollow cylindrical stator section and a rotor section rotatably accommodated, and an annular gap forming the mixing chamber formed between the rotor section and stator section.

Abstract: A system and methods for maintaining separation between substances such that the substances can be mixed as needed. The substances may be a liquid or a solid and may be edible or non-edible. More specifically, the present invention is directed to a system and methods that include an apparatus including at least two vessels, an additive vessel and a receiving vessel, for maintaining the separation of the substances and facilitating the mixing of the substances as needed.

Abstract: A mixing device configured for shipment and/or storage includes a base housing at least one motor, a jar removably mountable to the base in an operating configuration for containing foodstuff, and a blade assembly loosely positioned in the jar. The blade assembly has a first surface and an opposing second surface. The second surface of the blade assembly operatively engages that at least one motor in the operating configuration. The device further includes a blending tool operatively connected to the first surface of the blade assembly and an enclosure removably mountable to the first surface of the blade assembly to enclose the blending tool.

Abstract: This invention is a stirrer, impeller or stirrer paddle used for mixing small volumes of liquid in a vessel having a small capacity for liquid, said impeller being characterized by an impeller blade connected to the bottom portion of a support, where the blade has an opening extending through the blade from the front to the back surface of the blade said opening extending across the rotational axis of the impeller. The invention is also an apparatus comprising that blade, a method of mixing components using the apparatus and an array of two or more of the apparatuses.

Abstract: A process for mixing one or more liquid compositions comprising the steps of: a. providing one or more containers for said liquid composition, wherein said container has a volume capacity of from about 10 ml to about 200 ml; b. filling said one or more container with said one or more liquid composition; and c. stirring said composition with a helical type mixer at a speed of from about 10 rpm to about 750 rpm; wherein at least one of said liquid compositions has a viscosity of from about 0.5 Pa-s to about 20,000 Pa-s.

Abstract: A blender apparatus (10) includes a blender jar (14) having a base (16) and a container (18) for receiving food products; and a blade mechanism at least partially disposed within the blender jar (14). The blade mechanism includes a drive shaft (32) defining a shaft axis and being engageable with a drive mechanism for rotating the drive shaft (32) and first and second cutting blades (36, 38) mounted to the drive shaft (32). The first cutting blade (36) generally extends along the shaft axis and has at least one cutting edge (40) while the second cutting blade (38) traverses the shaft axis and also has at least one cutting edge (44). The first cutting blade (36) may have opposed cutting edges (40). The opposed cutting edges (40) may be dimensioned to extend to an apex (42) of the first cutting blade (36). The apex (42) may be generally sharp. The second cutting blade (38) may include a pair of opposed lobes (46) with each lobe (46) defining an arcuate profile and having a cutting edge (44).

Abstract: A seabed region (18) that lies under a seabed surface area of over one square meter, is analyzed by comparing a core sample taken near the middle of the region and/or data from a geotechnical insitu cone penetrometer installed at the middle of the region, to an acoustic analysis of the region. Locations of the acoustic analysis are precisely correlated to the location of the core test sample or cone test by mounting an acoustic imaging apparatus (16) that holds acoustic transducers (44, 46), on a carriage (26) that is positioned on the core drill (12) or cone penetrometer barrel staff. The carriage of the acoustic imager apparatus is clamped to the core drill when the core drill is not rotating. An arm (30 and/or 32) is supported on the carriage through a frame (28), with at least one acoustic generator (44) and one acoustic echo detector (46) mounted on the arm. The arm can be rotated to positions lying about the drill axis (14) to accurately scan a wide area.

Abstract: The method disclosed is useful for estimating anisotropic properties of an earth formation. The method includes extracting travel time values of components of the acoustic wave induced from a downhole tool and reflected from a boundary bed formation. The method further includes obtaining a travel time ratio of the wave components and using the travel time ratio to estimate the anisotropic properties of the formation.

Abstract: A waterproof or water-resistant membrane cover for the acoustic transducer array of a sodar system. The membrane is placed over each transducer of the array. The membrane may be spaced from the array, with a structure such as a frame used to hold the membrane in place relative to the array.

Abstract: A system and method for detecting, identifying, and fixing the location of the source of an acoustic event. The inventive system includes: a plurality of sensors dispersed at somewhat regular intervals throughout a monitored area; a communication network adapted to deliver information from the sensors to a host processor; and a process within the host processor for determining, from the absolute times of arrival of an event at two or more sensors, a position of the source of the event. Acoustic events are detected and analyzed at each sensor so that the sensor transmits over the network: an identifier for the sensor; an identifier for the type of event; and a precise absolute time of arrival of the event at the sensor. In a preferred embodiment, the system also identifies the type of weapon firing a gunshot.

Abstract: A submersible loudspeaker assembly is provided. The loudspeaker assembly includes: a housing; a loudspeaker enclosed within the housing; an external diaphragm disposed adjacent to the loudspeaker. The external diaphragm is acoustically transparent when subject to ambient air pressure, but configured to flex towards the loudspeaker when submerged in water.

Abstract: A clockwork movement includes a control member actuatable by a control lever in response to a user's action and having the form of a column wheel. The control member is rotatably mounted on the clockwork movement frame around an axis X, perpendicular thereto, for controlling first and second mechanisms exhibiting at least one movement function such as chronograph or alarm function. The control member includes rotationally fixable first, second and third parts which are mounted on a shaft at first, second and third levels, respectively, in a direction of the axis X for interacting with the control lever and for controlling the mechanisms. The shaft which is pivotally mounted with respect to the frame is arranged in at least two bearings, which are positioned remotely to each other for ensuring the shaft good stability, whereas the second and third parts are located on the both parts of the frame.

Abstract: The invention concerns an escapement (1) for a timepiece comprising an anchor (2) articulated on a stem (3) and co-operating with an escapement mobile (4) articulated on an axis (5), said mobile comprising a plurality of teeth (8; 15, 16) uniformly spaced around said mobile, said anchor including an entry pallet (6) and an exit pallet (7) arranged to receive alternately an impulse from one of the teeth borne by the mobile and for acting as rest plane for said tooth. The invention is characterized in that the escapement mobile (4) comprises first and second integral and coaxial wheels (13, 14) including each the same number of teeth (15, 16), in that the entry and exit pallets (6, 7) co-operate respectively with the first and second wheels (13, 14) and in that the peripheral radius (R1) of the first wheel (13) is greater than the peripheral radius (R2) of the second wheel (14).

Abstract: The escapement includes an escape wheel set (1), a balance roller (3) carrying an impulse pin (4) and a first impulse pallet stone (5). It further includes a pallet assembly (8) fitted with a second impulse pallet stone (11) and first and second locking pallet stone (12, 13). The wheel set (1) includes at least one escape wheel fitted with teeth (6) that mesh directly with the teeth (20) of the first wheel of a gear train (2), the teeth (6) of the wheel (1) cooperating with the impulse pallet stones and locking pallet stones.

Abstract: According to one embodiment, a control method, includes moving a pickup head to an adjustment position adjusting the quantity of adjustment of focus balance measuring the amplitude of an RF signal in the adjustment position adjusting the focus balance adjustment quantity and measuring the RG signal amplitude a plurality of times estimating the focus balance adjustment quantity at which the RF signal amplitude is maximized from the measured focus balance adjustment quantities and RF signal amplitude moving the pickup head to a different adjustment position estimating the focus balance adjustment quantity at which the RF signal amplitude is maximized in the different adjustment position by adjusting the focus balance adjustment quantity and measuring the RF signal amplitude a plurality of times and adjusting the focus balance adjustment quantity to the focus balance adjustment quantity estimated in the different adjustment position.

Abstract: A land/groove switch position detecting method includes measuring information about a land/groove switch generation timing of a disc, using a first signal having a frequency that varies in proportion to a rotation speed of the disk in a normal playback mode, and a second signal having a predetermined frequency higher than the frequency of the first signal, and calculating a predicted land/groove switch generation position in the seek mode, using the information about the land/groove switch generation timing.

Abstract: The invention relates to a tilt controller for controlling the tilt (radial and/or tangential) of an actuator relative to a recording surface of an optical storage medium, compensation for the radial to tilt crosstalk being effected by feeding a filtered version of the radial control signal (r) into the tilt branch, and/or compensation for the focus to tilt crosstalk being effected by feeding a filtered version of the focus control signal (f) into the tilt branch.

Abstract: An optical disc recording system includes a host apparatus configured to issue commands; and an optical disc recording apparatus configured to carry out a process corresponding to each of the commands, and to reply a response data to the command to the host apparatus. The host apparatus issues a record command as one of the commands to record a record data in an optical disc medium, and an optical disc recording apparatus records the record data in a data area in a predetermined format in response to the record command, wherein the optical disc comprises the data area and a first control data recording area. The optical disc recording apparatus additionally sets each of second control data recording areas in the data area in association with a command from the host apparatus as one of the commands, and a record status control data is recorded in the first or second control data recording area to indicate record status of the record data.

Abstract: Accurate calibration of recording power is performed without exceeding a rated output value of a laser diode even if recording speed is increased and high recording power is required. An information recording apparatus records information on an information recording medium such as a DVD-R/RW or a DVD+R/RW by applying a laser light onto the information recording medium. A pickup has a laser light source. A light receiving unit for detecting the amount of light by receiving the laser light emitted from the laser light source is provided, and the power of the laser light is controlled based on the power of the detected laser light. Before the actual information recording, a test emission is performed during calibration to determine an adequate recording power, and the emission duty of the laser light is controlled within the range not exceeding the rated output value of the laser light source.

Abstract: A disk drive data storage system comprising at least one data storage disk and a sensor assembly proximate the data storage disk. The sensor assembly further comprises circuitry for writing data to the data storage disk and circuitry for reading data from the data storage disk. The system also comprises circuitry for controlling the circuitry for reading data during different time periods so that the circuitry for reading data consumes different levels of power while the circuitry for writing data is writing data to the data storage disk.

Abstract: An optical disc device and recording power control method that can ensure the recording quality of data recorded on an optical disc are suggested. When recording data on an optical disc, data recorded on the optical disc is reproduced periodically; a ? value, an index of recording quality of the data on the optical disc, is obtained based on a waveform of the reproduced data; a correction factor of recording power is calculated based on the obtained ? value, and the recording power is corrected according to the correction factor; at the same time, a recording area of the optical disc is divided into a plurality of zones and the correction factor for each zone is managed; and the recording power is corrected according to the correction factor of the zone where data is to be recorded next on the optical disc.

Abstract: A recording device for recording information at addressable locations on a removable record carrier for storing data. The device comprises monitoring means (31) for monitoring recording of the data by storing recorded data addresses in a memory. Further, the device comprises examining means (32) for retrieving the recorded data based on addresses read from the memory, and for checking the recorded data addresses for presence of special data. This allows for tracking of changes of the special data stored on the record carrier. The device is capable of generating additional data depending on the special data and of recording the additional data on the record carrier without reading all the special data.

Abstract: In a method for recording information on an information recording medium having a data recording area for storing user data and a test area used for test recording by a recording apparatus, it is detected whether the test area is unusable when executing the test recording. The test recording is executed in the test area when the test area is detected not to be unusable, or executed in the data recording area when detected to be unusable. Management information relating to the test recording executed in the data recording area is recorded in a predetermined area. Hence, it is possible to eliminate a limit of number of times of test recording which depends on the size of the test recording area.

Abstract: According to one embodiment, an optical disk apparatus is provided with a read section which reads data from an optical disk to output read information, a determination section which determines presence/absence of an error of the read information to output an error presence/absence signal, a transfer processing section which receives the error presence/absence signal and receives a hash request signal and transfers the hash request signal when the error presence/absence signal indicates the absence of an error, and does not transfer the hash request signal when the error presence/absence signal indicates the presence of an error, and a processing section which performs hash processing to the read information upon reception of the hash request signal.

Abstract: The invention relates to a control method and system (90) for a disc drive apparatus (1) in which, if the temperature of, for example, the laser is determined to be too high, the control unit (90) is arranged to either: 1) first cause the disc drive apparatus (1) to enter a duty cycle mode, in which the apparatus is alternately operative in a normal mode and an energy saving mode, and then, if the temperature is determined some predetermined time later to still be too high, cause the write speed of the apparatus to drop to the next available write speed, e.g. 16× to 12× or 10× to 8×, etc . . . , or 2) first cause the write speed of the apparatus to drop to the next available write speed, and then, if the temperature is determined some predetermined time later to still be too high, cause the disc drive apparatus 1 to enter a duty cycle mode as defined above.

Abstract: The invention relates to a method and system for adjusting the pitch of an array of light spots (103) in an information carrier reading apparatus so as to correspond with the size of the macro-cells in which data is stored. A degree of mismatch between the pitch of the array of light spots (103) and the size of the macro-cells is determined when the probe array generation device (102) is illuminated with an input light beam, and the pitch adjusted accordingly by adjusting the distance of the focus of the light source (12) so as to converge or diverge the input light beam (104) to the probe array generation device (102), thereby to create a non-collimated input light beam (104) and magnify the pitch of the array of light spots (103) accordingly.

Abstract: When a laser light focal point, driven by an objective lens, passes through each of a plurality of recording layers of an optical disc, data recorded on the recording layers through which the focal point passes may be deteriorated due to a difference in optical sensitivity for each recording layer or the like. In a focal point position movement in which switching of recording layers is made by a focus error signal, when the focal point position moves from a recording layer on which a laser light is focused to another recording layer which is not adjacent, light intensity or light density at the focal point is reduced in accordance with the recording layer to be passed through, thus deterioration of the data on the optical disc being prevented.

Abstract: In order to ensure recording quality while suppressing the adverse effects due to performance variations among apparatuses and disc radial positions on an optical disc, an optical disc apparatus according to the present invention performs, at the time of data recording, the steps of: acquiring a jitter value and ? value from a reproduced signal based on laser light reflected from the optical disc in relation to a disc radial position; learning a ? value when the acquired jitter value is a minimum as a target ? value; and, if a jitter value acquired thereafter is larger than the minimum jitter value by a preset reference value or above, correcting recording power based on the magnitude relation and the difference between the ? value associated with the acquired jitter value and the target ? value or performing trial record processing.

Abstract: To adjust the parameters of a write strategy for recording data on an optical recording medium, the jitter value of a reproduced signal obtained from recorded data is detected. If the jitter value exceeds a prescribed threshold, a write strategy parameter having a comparatively small effect on the jitter value is adjusted, and subsequent data are written on the recording medium using the adjusted parameter. Parameters are selected for adjustment in ascending order of their effect on the jitter value. Stable data recording can thereby be carried out without significant jitter degradation.

Abstract: A method to map defects is provided. A select data track of a storage medium is scanned for a defect. At least one data wedge affected by the defect on the select data track is identified. Each data wedge includes available area for writing user data defined between two servo wedges that include position information. The at least one affected data wedge is identified as unusuable.

Abstract: The disclosure is related to pulse width modulating a power signal to a heat resistive element of a transducer. The power signal may be a power output signal of preamplifier. The power signal may be provided to a heat resistive element in a transducer that is operable to read data from or write data to a data storage medium. The pulse width modulated power signal can allow for controlling the heating of the heat resistive element based on a thermal time constant of the heat resistive element and based on adjustable components of the pulse width modulated power signal.

Abstract: An exemplary method for optimizing a recording signal of an optical recording apparatus to record data onto a disc, the recording signal having a first pulse-width parameter, the method includes selecting an initial value of the first pulse-width parameter; generating adjusted values based on the initial value to record test data onto the disc respectively; measuring mark lengths of lands; determining average lengths of the mark lengths of lands; determining differences between the average lengths and a predetermined standard length; linear curve fitting the adjusted values and the differences employing the following linear curve fitting equation: Y=AX+B to obtain the constants A and B, wherein X represents the adjusted values, Y represents the differences; determining and storing an optimum value of the first pulse-width parameter to be used for recording the data onto the disc, this optimum value equals to ?B/A. An optical recording apparatus is also provided.

Abstract: A writing strategy parameters indexing method and a recording apparatus therefor. The writing strategy parameters indexing method includes operations of receiving an NRZ sequence; moving the NRZ sequence by as much as a bit with respect to a channel block using a slide-window having a length of N bits; determining whether a bit pattern of the NRZ sequence in the window-slide has a predetermined bit pattern; extracting writing strategy parameters corresponding to the predetermined bit pattern when the bit pattern of the NRZ sequence in the window-slide has the predetermined pattern; and generating recording pulses using the writing strategy parameters.

Abstract: A data recording method according to the present invention is a method for recording data as edge position information, including marks and spaces of multiple different lengths, on a storage medium by irradiating the storage medium with a pulsed energy beam. The method includes the steps of: (A) generating a write code sequence based on the data to be recorded; (B) determining a write pulse waveform, defining the power modulation of the energy beam, according to the code lengths of respective codes included in the write code sequence; and (C) modulating the power of the energy beam based on the write pulse waveform.

Abstract: A method for obtaining and setting recording setting information, including: obtaining device identification information of an optical disc recording/playback device; transmitting a recording setting information request signal including at least the device identification information to a server connected through a network; receiving recording setting information corresponding to at least the device identification information transmitted from the server based on the recording setting information request signal; and storing the received recording setting information in memory within the optical disc recording/playback device. Thus, for example, recording setting information as to all of optical discs may be obtained and set as much as possible in a case wherein access to the server can be performed, whereby even a case can be handled wherein data recording is carried out as to various types of optical discs later.

Abstract: According to one embodiment, there is provided a recording apparatus including a recording unit which copies first contents with a first number of producible copies and records second contents with a second number of producible copies in a recording region, and a management unit which arbitrarily distributes the second number of producible copies from the first number of producible copies when the recording unit copies the first contents to record the second contents in the recording region and, thereby rewrites the first number of producible copies with a new first number of producible copies subtracted by the distributing process and the copy process of the contents.

Abstract: Proposed are a method of fabricating an optical information recording medium that can prevent the degradation of the appearance caused by a hardening resin entering between a center cap and a substrate due to capillary action, and an optical information recording medium using a substrate for implementing the method. The optical information recording medium has a reflective layer and a recording layer on a first surface of a circular substrate having a through hole in a center part, and an optically transparent cover layer is provided on the recording layer. The substrate has an inner diameter of an area near an opening of the through hole on the first surface greater than that of another portion of the through hole. A step part is formed on the surface on the light incident side, that is, formed around the through hole on the surface on which the reflective layer and the recording layer are formed.

Abstract: An optical disc drive apparatus, for recording/reproducing upon/from an optical disc medium having a plural number of recording layers, comprises a recording/reproducing element, which is configured to irradiate a laser upon the optical disc medium, to as to conduct recording/reproducing thereon/from, wherein recording is conducted within a region of an arbitrary range on the optical disc medium by means of the recording/reproducing element, and the region is used for moving an optical spot of the laser irradiated from the recording/reproducing element when recording/reproducing data thereon/from.

Abstract: According to one embodiment, an optical disc distinguishing method includes irradiating the loaded optical disc with a light beam having one of a first to third wavelengths, determining whether the loaded optical disc belongs to a first group consisting of a first to third optical discs or a second group consisting of two kinds of optical discs which do not correspond to the wavelength of the irradiated light beam, identifying the loaded optical disc as one of the first to third optical discs, irradiating the loaded optical disc with one of the two kinds of the light beams except for the light beam with which the loaded optical disc is irradiated in making the determination of the group when the loaded optical disc belongs to the second group, and identifying the loaded optical disc as one of the two kinds of the optical discs belonging to the second group.

Abstract: A write-once read-many information recording medium is provided, which is capable of easily searching for a latest DDS and a latest defect list. At least one disc management working area is sequentially allocated in a predetermined direction on the write-once read-many information recording medium of the present invention. The latest defect list and the latest DDS are provided in a recorded disc management working area neighboring a border between the recorded disc management working area and an unrecorded disc management working area, where the latest defect list precedes the latest DDS in the predetermined direction.

Abstract: Reproduction reference light is irradiated on a hologram recording medium on which imaged digital data are recorded as a plurality of element holograms in the form of interference fringes obtained by interference between object light of the digital data and recording reference light. Then, a reproduction image obtained from the hologram recording medium by the irradiation of the reproduction reference light is detected. Then, readout data are produced based on the detected reproduction image. Thereafter, it is discriminated whether or not the readout data should be stored into a memory, and the readout data are stored into the memory in response to a result of the discrimination. Where a predetermined amount or more of the data is accumulated in the memory, reproduction data are produced from the readout data accumulated in the memory and then reproduced.

Abstract: An optical head includes semiconductor lasers for 455 nm, 655 nm, and 785 nm bands; a polarization change element and a polarizing beam splitter for luminous flux with a wavelength of 455 nm band, a first collimation lens for converting luminous flux having passed through the polarizing beam splitter into parallel flux, a first quarter-wave plate, a BD objective for focusing the flux onto a signal recording surface of BD, a first photo-detector for receiving light reflected by BD, a composite prism for reflecting flux reflected by the splitter and transmitting most of flux from the lasers for 655 nm and 785 nm bands, a second collimation lens for converting flux emitted from the composite lens into parallel flux, a second quarter-wave plate, an objective compatible with HD DVD, DVD, and CD; and a second photo-detector for receiving light reflected by HD DVD, DVD, and CD.

Abstract: An optical reading/writing apparatus has an optical head that includes a collimator and a lens. For efficient and reliable focusing control for writing an empty optical disk, calibration of focus offset and spherical aberration is executed by setting a boundary and performing data-reading in an OPC area only with combinations of focus offset and spherical aberration within the boundary. Accordingly, an optimum combination of focus offset and spherical aberration is determined for focusing compensation in subsequent writing operation of the empty disk.