The invention provides a vertical turret lathe capable of preventing an inner diameter turning tool attached to a turret tool rest from interfering with a workpiece during machining of the outer diameter of the workpiece. The vertical turret lathe comprises a work table that holds a workpiece W1 and rotates, and a working head 40 having a turret tool rest 50 and capable of moving in X-axis and Z-axis directions. A tool holder 70 for holding an inner diameter turning tool T2 via hydraulic pressure is attached to a part of the tool supporting portions 60 of the turret tool rest. The automatic tool changer apparatus 100 includes a turret-type tool magazine 120 and pistons 160 and 162, which mechanically press the pins 74 and 76 of the tool holder 70 and clamp or unclamp the tool T2.

A cutting insert having a plurality of corner cutting edges has an upper face, a lower face, two longitudinal side faces and two transversal side faces connecting the upper face and the lower face. A through hole passes through central parts of the upper face and the lower face. The longitudinal side faces are opposite to each other and normal to both upper and lower faces, as are the transversal side faces. The upper face and the lower face are each provided with two chip discharge grooves, each chip discharge groove extending along a corresponding one of the transversal side faces, the two chip discharge grooves being inclined oppositely in the transverse direction so that the upper face and the lower face are each provided with two corner cutting edges at diagonally opposite corners. The longitudinal length of the insert is longer than the transversal length of the insert. The cutting insert can be mounted stably to a small-diametered cutter with a sufficient mounting surface.

A milling tool for slot milling includes a tool body and a plurality of separated first seats, which form root insert seats for root inserts arranged one after the other along a first line and a plurality of separated flank insert seats that includes a plurality of second seats for flank inserts . The plurality of second seats is arranged one after the other along a second line on a primary side of the root insert seats. A plurality of third seats for flank inserts is arranged one after the other along a third line on a secondary side of the root insert seats. Each flank insert seat includes a bottom surface, an inner side surface, and an outer side surface. Each flank insert includes an under side, an opposite upper side, and a circumferential edge side that forms a rake face connecting the upper side and the underside.

A cutting insert of the present invention includes an upper surface; a lower surface; a side surface; a cutting edge which is located along an intersection of the upper surface and the side surface, and comprises a major cutting edge, a flat cutting edge, and a minor cutting edge located between the major cutting edge and the flat cutting edge; and a land part located along the cutting edge on the upper surface. The land part includes a minor cutting edge land portion located correspondingly to the minor cutting edge. The minor cutting edge land portion is inclined downward toward a central part of the upper surface. The present invention also provides a cutting tool including the cutting insert, and a method of manufacturing a machined product by using the cutting tool.

A cutting insert has at least first and second side surfaces, with a chip-control arrangement. The chip-control arrangement includes at least one projection disposed at an intersection of a corner of the cutting insert. When the chip-control arrangement includes two projections they can be disposed symmetrically on both sides of the intersection. Each of the at least one projections is elongated and extends longitudinally along an associated side surface.

A cutting insert is capable of boring or drilling without the formation of a prepared hole in a workpiece. A cutting edge includes a cutting edge portion extending from the outer peripheral side to the tool center axis side of a cutting tool body when the cutting insert is attached to a mounting seat, reaching a first plane including the tool center axis, and traversing from one side to the other side of a second plane which is perpendicular to the first plane and which includes the tool center axis.

A cutter insert assembly for a drill bit for boring into the earth, comprising a super-hard structure clampable to a support body by means of a clamp mechanism; the clamp mechanism comprising opposed or opposable compression members connected or connectable by a tension member capable of sustaining a clamping force between the compression members when the cutter insert assembly is in a clamped condition, in which condition the compression members exert opposing compressive forces on the super-hard structure and the support body, operable to clamp the super-hard structure to the support body, and in which condition the cutter insert assembly is self-supporting and capable of being mounted onto a drill bit body.

A cutting tool includes a polygonal cutter body and an end cutting insert for chipforming machining mounted in a serrated seat disposed at an axial end of the cutter body. A bottom surface of the insert has a plurality of parallel serrations meshing with corresponding serrations of the seat. The serrations extend transversely relative to the longitudinal axis for resisting axially rearward cutting forces applied to the insert. The seat is formed directly by the cutter body, or by a shim disposed beneath the insert. The shim is provided with a downward lip to transfer axial forces to the cutter body. The insert can be square or triangular, wherein the serrations are in the form of a plurality of sets of parallel serrations disposed adjacent respective cutting edges.

A cutting insert with a substantially triangular or square basic form is particularly suited for face milling at high feed rates. It has convex cutting edges, which are each made up of a circular arc and at least one straight portion. Each cutting edge has, adjoining a cutting corner, a straight face cutting edge that merges with a main cutting edge, having 1 to 3 straight portions, a circular portion with a radius of at most 80% of the radius Ri of the inscribed circle. The cutting edges have an all-round cutting edge chamfer with a chamfer angle α. This chamfer angle α has along the cutting corners a value in the range from −10° to −20° and changes continuously along sub-portions of the face cutting edge and main cutting edge and along the circular portion to a constant value in the range from 0° to −10°.

A cutting insert includes an upper surface; a lower surface; a side surface which is connected to each of the upper surface and the lower surface and includes a first side surface, a second side surface and a third side surface being adjacent to each other in order; an upper cutting edge including an upper major cutting edge located at an intersection of the upper surface and the first side surface, and an upper flat cutting edge located closer to the upper major cutting edge in an intersection of the upper surface and the second side surface; and a lower cutting edge including a lower major cutting edge located at an intersection of the lower surface and the third side surface, and a lower flat cutting edge located closer to the lower major cutting edge in an intersection of the lower surface and the second side surface. The second side surface comprises an upper flank surface connected to the upper flat cutting edge, and a lower flank surface connected to the lower flat cutting edge. As going from the upper surface to the lower surface, the upper flank surface is closer to a central axis extending between the upper surface and the lower surface and the lower flank surface is separated from the central axis in a side sectional view. A cutting tool including the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.

A cutting insert having excellent chip discharge performance is provided. The cutting insert (1) according to an embodiment of the present invention includes an upper surface (2), a lower surface (3), a side surface (4) connected to the upper surface (2) and the lower surface (3), and a cutting edge (5) which is located at an intersection of the upper surface (2) and the side surface (4), and includes a major cutting edge (51) and a flat cutting edge (52). The major cutting edge (51) includes a major cutting section (512) which has a concave shape and is inclined downward as a straight line connecting both ends thereof is away from the flat cutting edge (52) in a side view. A cutting tool (11) according to an embodiment of the present invention includes the cutting insert (1) and a holder (10) configured to attach the cutting insert (1) thereto.

An upper surface of a cutting insert includes a first rake face and a second seating surface. A lower surface of the cutting insert includes a second rake face and a first seating surface. The cutting edge includes a first cutting edge portion formed at a crossing edge line portion between the first rake face and a flank face and a second cutting edge portion formed at a crossing edge line portion between the second rake face and the flank face. The first cutting edge portion and the crossing edge line portion between the first seating surface and the flank face are positioned opposite each other. The second cutting edge portion and the crossing edge line portion between the second seating surface and the flank face are positioned opposite each other.

A cutting insert according to an embodiment of the present invention includes an upper surface; a lower surface; a side surface located between the upper surface and the lower surface; at least one concave part extending in a thickness direction in the side surface, and having one end thereof located at the upper surface; and a cutting edge which is located at an intersection region of the upper surface and the side surface, and is divided into a plurality of divided cutting edges with the at least one concave part interposed therebetween. The upper surface includes a first raised part located inwardly of the at least one concave part, and a plurality of second raised parts respectively located inwardly of the plurality of divided cutting edges. The plurality of the second raised parts are located inward compared to one end of the first raised part close to the cutting edge in a top view. A cutting tool including the cutting insert, and a method of manufacturing a machined product using the cutting tool are also provided.

A cutting insert according to an embodiment of the invention includes: an upper surface; a lower surface; a side surface which is connected to each of the upper surface and the lower surface, and includes a first side surface and a second side surface adjacent to each other; and a cutting edge including a major cutting edge located at an intersection of the upper surface and the first side surface, and a minor cutting edge located at an intersection of the upper surface and the second side surface. The upper surface includes a rake surface which is located along the major cutting edge, and is inclined downward as the upper surface separates from the major cutting edge. The second side surface includes a second upper constraining surface and a second lower constraining surface in order as the second side surface goes from the upper surface to the lower surface. The second upper constraining surface is inclined inward at an inclination angle α1 with reference to a central axis extending between the upper surface and the lower surface. The second lower constraining surface is continuous with the second upper constraining surface, and is inclined outward at an inclination angle α2 with reference to the central axis. A cutting tool with the cutting inserts, and a method of manufacturing a machined product by using the cutting tool are also provided.

A milling cutter for chip removing machining, including a basic body rotatable in a predetermined direction around a center axis and having a front end surface and an envelope surface that extends axially backward from the front end surface and is concentric with the center axis. A number of indexable milling inserts are mounted in respective peripherally spaced-apart seats having a mutually fixed pitch, each milling insert including an upper side, an under side and at least one clearance surface, the clearance surface together with the upper side delimiting at least two alternately active cutting edges that are uniform in their extension between first and second end points. The cutting edges of each milling insert are situated on different levels in relation to the under side of the milling insert to alter the effective pitch between the active cutting edges of the milling inserts by indexing of at least one of the milling inserts.

A double-sided cutting insert may generally comprise a top surface, a bottom surface, at least one side surface interconnecting the top surface and the bottom surface and forming at least one cutting edge, a through hole extending between the top surface and bottom surface, wherein each of the top surface and bottom surface comprise at least one anti-rotation element. The cutting insert may comprise a single anti-rotation element on the top surface and a single anti-rotation element on the bottom surface. The anti-rotation element may be proximate to the through hole. A cutting tool using the cutting inserts, as well as methods of making and using the same are also described.

A cutting insert is provided with a plurality of cutting portions formed at the intersection portion of each end surface and a peripheral surface. Each cutting portion includes first and second cutting edges. First corners and second corners which differ in their internal angles are alternately formed in each end surface. An internal angle of the first corner is smaller than an internal angle of the second corner. Each first cutting edge has a portion extending to approach the median plane as a distance from a corresponding first corner increases. A first side surface portion extending on the peripheral surface from each first cutting edge forms an insert internal obtuse angle, and a second side surface portion extending on the peripheral surface from each second cutting edge forms an insert internal acute angle.

Provided is a surface-coated cemented carbide insert obtained by containing at least WC powder and Co powder as raw materials, including a WC-based cemented carbide obtained by forming and sintering mixed raw materials containing at least any of (a) Zr compound powder, Nb compound powder, and Ta compound powder, (b) complex compound powder of Nb and Ta, and Zr compound powder, (c) complex compound powder of Nb, Ta, and Zr, (d) complex compound powder of Nb, Zr, and Ta compound powder, and (e) complex compound powder of Ta and Zr, and Nb compound powder, as essential powder components, as a substrate, and forming a hard coating layer on the substrate by vapor deposition, in which a Co enrichment surface region is formed in a substrate surface, Co content in the Co enrichment surface region satisfies to be between 1.30 and 2.10 (mass ratio) of Co content in cemented carbide.

A roughing end mill comprises an end mill body and plural inserts which are placed on an outer circumference of the end mill body with a predetermined distance apart from each other in the axial direction of the end mill body, wherein the plural inserts form plural insert rows which are provided in a circumferential direction of the end mill body, where the inserts are offset in the axial direction from each other between the different insert rows which are adjacent in the circumferential direction. The inserts have waveform cutting edges which face towards an outer circumferential side of the end mill body. One insert of one insert row and an insert of another insert row are positioned such that the waveform cutting edges of each of these inserts make up a waveform cutting edge row whose phase is continuous on a rotation trajectory around the axis.

A cutting insert (14) is formed with an insert aperture (32) opening out to insert top and bottom surfaces (14A, 14B) of the cutting insert (14). In a plan view of the insert top surface (14A), the cutting insert (14) and the insert aperture (32) both have oblong shapes which are elongated along a common insert longitudinal axis (AIL). The aperture (32) includes first and second side surfaces (32A1, 32A2) which each extend along the insert longitudinal axis (AIL), and aperture first and second end surfaces (32B1, 32B2) which each extend transverse relative to the insert longitudinal axis (AIL). At least one of the aperture first and second end surfaces (32B1, 32B2) is formed with a clamping lip (32C1, 32C2).

A cutting tool used for grooving and turning operations where a cutting insert is resiliently securable in a holder blade. The cutting insert includes an insert central lower surface located between, and recessed with respect to, two insert lower component surfaces, each having an insert lower abutment surface. At least one of the two insert lower component surfaces includes an insert inner curved ramp extending from its insert lower abutment surface to the adjacent insert lower intermediate surface and at least the other of the two insert lower component surfaces includes an insert outer curved ramp extending from its insert lower abutment surface to an adjacent end surface.

A cutting insert includes a first surface having a first rake surface, a second surface having a second rake surface, a central axis of the insert extending between the first and second surfaces, four side surfaces extending between the first surface and the second surface, and four cutting edges. Each cutting edge has a first cutting edge component and a second cutting edge component and being associated with a respective one of the first and second surfaces and with two respective ones of the side surfaces. The first rake surface is identical to the second rake surface and the first rake surface and the second rake surface are oriented at a 90° angle to each other about the central axis of the insert.

A dual scanning and FTIR system for application in the Terahertz and broadband blackbody frequency range including sources for providing Thz and broadband blackbody range and electromagnetic radiation, at least one detector of electromagnetic radiation in the THZ and broadband blackbody ranges, and at least one rotating element between the source and detector.

In certain embodiments, the present invention provides a compound power converter in which the majority of power passes from input to output through only a single stage of power conversion. At least one embodiment includes a main converter with an auxiliary output. The auxiliary output energizes a reservoir that provides input power for a supplemental converter capable supplying the main output. The supplemental converter improves regulation and can provide holdover power for Power Factor Correction (PFC) or Uninterruptible Power Supply (UPS) operation.

A power converter includes an active front end (AFE) that is coupled by a dc link stage to a plurality of H-bridge inverters. One or more multi-phase electro-magnetic energy conversion devices, such as transformers or electric machines, with open windings that are connected to only the AFE or only the H-bridge inverters or to both the AFE and H-bridge inverters, provide a regenerative or partial regenerative power converter.

A system, method, and apparatus for providing three level inverter modulation is disclosed. In one embodiment, control signals can be provided to control a three level inverter in a power converter based on at least one feedback signal.

Provided is a configuration in which it is possible to mount an applied voltage suppression circuit configured to prevent voltage breakdown of a semiconductor switching element, and a set voltage thereof can be inspected without damaging an IC or the like of a peripheral circuit. In a power converter having a semiconductor switching element, an applied voltage suppression circuit configured to suppress a voltage applied to the semiconductor switching element and at least one component of constituent components of a driving circuit which causes the semiconductor switching element to be turned off if the component is absent are transferred to and disposed on a slave substrate (separate unit) which is divided from and electrically connected to a master substrate including the semiconductor switching element, the driving circuit, a control circuit, and the like mounted thereon.

An alternating-current/direct-current converter includes a rectifier, a reactor, a capacitor, and a switching rectifier. The rectifier is configured to rectify alternating-current voltage output from an alternating-current power source, thereby converting the alternating-current voltage into direct-current voltage, and to output the direct-current voltage. The capacitor includes terminals. The switching rectifier is coupled to the AC power source and switchable to output the direct-current voltage to the capacitor.

The present invention is applied to a frequency converter used for a receiver. The frequency converter according to the present invention includes an LO signal generator (11) that generates an LO signal and outputs the LO signal; and a mixer (10) that multiplies a received signal that has been band-limited to a usable bandwidth of said receiver by the LO signal so as to convert the frequency of the received signal and outputs the resultant signal. Said LO signal generator is capable of varying a phase resolution.

Among many embodiments, a power conversion apparatus and a method for converting power are disclosed. The power conversion apparatus may include switching components configured to create an alternating current; a preemptive detector arranged and configured to provide, in advance of the alternating current reaching a zero-crossing, a control signal responsive to the alternating electrical current approaching the zero-crossing; and a controller configured, at least in part, to change a state of the switching components before the zero crossing, in response to the control signal.

A power converter and a method for balancing voltages across input capacitors are disclosed in the present application. The power converter includes: two DC input terminals; a first input capacitor and a second input capacitor; a first bridge arm and a second bridge arm connected in series with one another; and an output circuit configured to generate a signal required by the power converter based on the signals at a midpoint of the first bridge arm and a midpoint of the second bridge arm. The power converter further includes: a first voltage balancing unit and a second balancing unit configured to reduce a voltage difference between the first input capacitor and the second input capacitor. The power converter provided by the present application solves the problem of imbalance in the voltages across the first input voltage and the second input voltage.

A full bridge DC-DC converter to which a current doubler is applicable is provided and includes a transformer and a switching circuit that converts a high direct current voltage into a high alternating current voltage and then outputs the high alternating current voltage to the primary side of the transformer. In addition, an output circuit receives and processes the output of the secondary side of the transformer and supplies the processed output to an electric load. The output circuit includes a first inductor, a first contact resistor, a second inductor, a second contact resistor, a first diode, a third contact resister, a second diode, and a fourth contact resister.

A series resonant power converter includes a power stage comprising a switching circuit operating at least a resonant frequency. To achieve soft switching and provide current at a voltage through an inductive element. The power converter can also include a control circuit for controlling a phase angle of the current, for controlling a duty cycle of the switching circuit.

A switching power converting apparatus includes a coil unit, a bipolar junction transistor (BJT) controlling power transfer through the coil unit, and a current sensing resistor sensing a current flowing through the BJT so as to produce a sensed voltage thereacross. A switching controller includes a current source supplying a first current, a current generating module generating, based on an input voltage associated with the sensed voltage, a second current, which is proportional to the current flowing through the BJT, a multiplexing module selecting one of the first and second currents as an output current, and a driving module outputting, based on the output current, a driving current, which is proportional to the output current, to the BJT to thereby conduct the BJT.

Methods and systems for managing link voltages in a power converter, where single phase, three phase or universal systems can be used. Common mode management refers to shifting of voltages in a particular direction to perform transition between input and output ports, in addition to maintaining soft switching property. Voltages in power converters can be freely increasing and decreasing, and thus damage to the circuit can be caused if these voltages change are not controlled.

Disclosed is a grid-connected inverter and a method for filtering AC output thereof. The grid-connected inverter includes an AC output filter which includes two or more switchable filtering modules, with the power capacity of each filtering module corresponding to a different output power of the grid-connected inverter; a monitoring module which is used to perform realtime monitoring on voltage and current outputted by the grid-connected inverter; and a control circuit which is used to calculate an output power grade of the grid-connected inverter according to the voltage and the current monitored by the monitoring module and control switching to the filtering module having a corresponding power capacity according to the power grade, the power grade being selected from a plurality of power grades which are divided according to power capacities of the filtering modules.

There is provided an even-level inverter, including: a voltage-dividing circuit dividing input DC power into an even number of voltage levels; a plurality of switching devices connected to individual nodes of the voltage-dividing circuit having the even number of voltage levels; and a bidirectional switching device connected to the individual nodes of the voltage-dividing circuit through at least one of the plurality of switching devices and including at least two transistors. According to the present invention, the bidirectional switching device is implemented without a diode to thereby reduce conduction loss caused due to an anti-parallel diode included in the related art bidirectional switching device, and a neutral point of the voltage-dividing circuit is electrically separated from the switching devices to thereby control reactive power.

The invention discloses a voltage source converter and a voltage source converter system. The voltage source converter comprises: a multi-level voltage source converter, being adapted to output a multiple levels of a first voltage at one of two first output terminals through a multiple of first conducting paths; a first energy store; and a first switching element, being arranged to directly connected with the first output terminal, and being adapted to switch the first energy store in or out of the first conducting path so as to combine a level of the voltage of the first energy store with the level of the first voltage as a second voltage output at a second output terminal. By having the topology as above, the voltage class of each of the power semiconductors can be kept lower with the number of the power semiconductors unchanged. Besides, VDRM is lowed as compared to conventional topology. This renders the reduction of the cost and the increase of the liability.

A molecule possessing a primary or secondary amino group and an additional functionality capable of providing a novel or improved property to a cellulose material has been permanently attached to the cellulose material in aqueous media using a water-soluble carbodiimide as the coupling agent/activator. One such molecule is 5-aminofluorescein (abbreviated as “A-fluo”) and one such cellulose material is a papermaking pulp. Papers made from a pulp furnish containing, for example, 0.01 wt. % of the “A-fluo”-attached pulp show an embedded marker feature authenticable upon UV or visible light excitation. The “A-fluo”-attached pulp can also be used for the marking and identification of a pulp furnish.

The invention encompasses devices and methods for treating one or more damaged, diseased, or traumatized intervertebral discs to reduce or eliminate associated back pain. Specifically, the invention encompasses intervertebral nucleus and annulus implants that are resistant to migration in and/or expulsion from an intervertebral disc space. The invention further encompasses kits including the implantable devices of the invention and associated delivery tools to treat annular and nuclear tissue.

A spinal fixation device includes a housing and a plurality of blades. Each blade includes a body having a central opening configured to rotate on a shaft within the housing. Control openings on opposing sides of the central opening are sized to engage prongs of a rotating tool. At least one cutting extension with a sharp leading edge extends from the body in an orientation about an axis of the shaft. Upon rotation of the blade by the rotating tool about the shaft in a direction in which the at least one cutting extension is oriented, the at least one cutting extension will break an endplate of a vertebra and hook into the vertebra.

Implants, tools and methods for performing unilateral posterior lumbar interbody fusion are provided. An interbody implant includes a body having a top and bottom surface extending along a length thereof; and first and second side surfaces extending between the top and bottom surfaces on opposite sides of the body. The height of the first side surface is greater than the height of the second side surface.

The intervertebral disc prosthesis comprises first and second plates (3, 4) designed to be attached on one of the two vertebrae adjacent to the intervertebral disc to be replaced, and a compression pad arranged between the first and second plates. Each plate comprises first attaching means including two attaching portions (14a, 14b) positioned symmetrically on either side of the anteroposterior median plane of said plate, second attaching means including two attaching portions (15a, 15b) positioned symmetrically on either side of a first plane inclined by an angle comprised between 50° and 70° relative to the anteroposterior median plane of said plate, and third attaching means opposite the second attaching means relative to the anteroposterior median plane and including two attaching portions (16a, 16b) positioned symmetrically on either side of a second plane inclined by an angle of approximately 90°, relative to the anteroposterior median plane of said plate.

Disclosed is an assembly and method for implant installation between adjacent vertebral bodies of a patient. The implant has a support body and a rotatable insert therein and the support body is curved for installation between adjacent vertebral bodies transforaminally. An installation instrument is also disclosed for removable attachment to implant and engagement with the rotatable insert to selectively permit rotation between the insert and the support body. The installation instrument extends along a longitudinal tool axis and when the installation instrument is in a first position the insert is rotationally fixed with respect to the support body and when the installation instrument is in a second position the support body may rotate with respect to the insert.

It is an object of the present invention to provide antimicrobial metallodrugs comprising an antimicrobial peptide (“AMP”) and/or an antibiotic covalently bound to a metal binding moiety. These metallodrugs combine a metal binding domain which typically catalyzes oxido-reductase chemistry or acts as a Lewis-Acid catalyst, with a member of a diverse class of antimicrobial agents currently validated in preclinical and clinical settings for the treatment of a broad spectrum of pathogenic organisms.

The present invention relates to a process to dissolve plutonium or a plutonium alloy, by placing it in contact with an aqueous dissolution mixture, wherein said dissolution mixture comprises nitric acid, a carboxylic acid with complexing properties with respect to plutonium, and a compound comprising at least one —NH2 radical such as urea. The invention also relates to a process to convert plutonium or a plutonium alloy into plutonium oxide and to manufacture nuclear fuel from said oxide.The invention particularly applies to the dismantling of plutonium contained in nuclear weapons with a view to its use in civilian nuclear reactors, particularly in the form of MOX fuel.

A method includes receiving first information identifying profile information associated with a customer, habit information associated with the customer's television viewing habits, or Internet usage information associated with the customer. The method also includes receiving preference information from the customer, wherein the preference information identifies advertisements or types of advertisements that the customer would like to view or would not like to view. The method further includes identifying advertisements based on the received first information and the received preference information, inserting, by a service provider, the identified advertisements in a television programming data stream and providing the identified advertisements to the customer.

A digital television system is connected to a mobile computing and communication device through an ad hoc communication link. A program broadcasted by the television system includes a plurality frames delivered in a sequential manner. A user can freeze a frame by employing the mobile device. The frame can then be transmitted to the mobile device and be redisplayed on the mobile device. The redisplayed frame includes visible symbols pointing to displayed items associated with advertising messages. The frame can also be stored in a photograph folder for the user to view the frame and associated advertising messages in a later time.

An inflight entertainment (IFE) system preloads from head end equipment onto seat end video caches subsets of prerecorded video entertainment programs from a library of prerecorded video entertainment programs stored on the head end equipment. Preloading is done independent of play requests made by passengers using the IFE system. The selected subsets are selected using selection metrics such as program popularity, passenger demographics and/or passenger preferences. The same or a different subset may be selected for different passengers. As a result of the selective preloading of the seat end video caches, if the head end equipment or the distribution system becomes inoperable during the flight, the IFE system is able to continue to deliver a limited offering of popular, demographically indicated and/or passenger preferred video entertainment from the seat end video caches, without requiring a large multiplier in storage capacity or loading time.

A method and apparatus for extracting advertisement keywords in association with situations of scenes of video include: establishing a knowledge database including a classification hierarchy for classifying situations of scenes of video and an advertisement keyword list, segmenting a video script corresponding to a received video in units of scenes, and determining a situation corresponding to each scene with reference to the knowledge database, and extracting an advertisement keyword corresponding to the situation of a scene of the received video with reference to the knowledge database.