A server migration planning system for planning server migration from source servers to destination servers is provided. A processor allocates the respective source servers to any ones of the destination servers, based on the resource usage of the respective source servers and resource capacity of the respective destination servers. The processor selects the source servers one-by-one in descending order of the resource usage, selects any one of the destination servers, and makes a comparison between a comparison-object usage as the resource usage of the selected source server and a remaining amount of the resource capacity of the selected destination server. If the comparison-object usage is more than the remaining amount, the processor selects another destination server and then makes the comparison again. If the comparison-object usage is not more than the remaining amount, the processor allocates the selected source server to the selected destination server.

According to the virtualization technology using virtualization software such as VMware and Xen, it is possible to make one physical server to operate as a plurality of virtual severs. As a result, it becomes easier to streamline a server operation according to the situation (refer to Japanese Laid Open Patent Application JP-P2005-115653A). It is also possible by using the virtualization technology to achieve "server migration" easily. The server migration is exemplified as follows.
FIG. 1 conceptually shows "server consolidation" as one example of the server migration. As shown in FIG. 1, let us consider a case where existing five physical servers M1 to M5 are operating and these five physical servers M1 to M5 are consolidated into three high-performance physical servers M6 to M8. For example, the physical servers M1 and M2 are respectively replaced with virtual servers VM1 and VM2 which run on the physical server M6. Also, the physical server M3 is replaced with a virtual server VM3 which runs on the physical server M7. Moreover, the physical servers M4 and M5 are respectively replaced with virtual servers VM4 and VM5 which run on the physical server M8. In the example shown in FIG. 1, the five physical servers M1 to M5 constitute a "source server group", while the three physical servers M6 to M8 constitute a "destination server group". Such the server consolidation can reduce occupation space and electric power consumption due to the decrease in the number of physical servers, which greatly contributes to reduction of operation management costs.
FIG. 2 conceptually shows "server reallocation" as another example of the server migration. As shown in FIG. 2, let us consider a case where a server operation is carried out with virtual servers VM1 to VM5 which run on physical servers M1 to M3. In the daytime when load is increased, the virtual servers VM1 and VM2 are built on the physical server M1, the virtual servers VM3 and VM4 are built on the physical server M2, and the virtual server VM5 is built on the physical server M3. On the other hand, in the nighttime when load is decreased, the virtual servers VM1, VM2 and VM4 are built on the physical server M1, the virtual servers VM3 and VM5 are built on the physical server M2, and thus the physical server M3 is not used. In this manner, the number of physical servers used is reduced depending on the situation, which can reduce the operation management costs. In the example shown in FIG. 2, the virtual servers VM1 to VM5 in the daytime or the nighttime constitute a "source server group", while the physical servers M1 to M3 constitute a "destination server group".
As described above, the server migration is important from the viewpoint of the reduction of the operation management costs. In advance of the server migration, it is necessary not only to estimate the number of servers under the post-migration situation but also to prepare a "migration plan" that indicates "to which destination server, each source server is allocated", i.e., an allocation relationship between the source servers and the destination servers. A fundamental condition that the migration plan should meet is an inclusion relation between computer resources. That is to say, the sum of "resource usage" of source servers which are to be allocated to a certain destination server must not exceed "resource capacity" of the certain destination server. Here, the computer resources include a CPU, disk, memory and network.
Also, a migration plan with which the number of servers under the post-migration situation becomes as small as possible is preferable from the viewpoint of the costs. When goods of various sizes are packed in bins with the same constant capacity, a problem of finding a minimum number of bins necessary for packing the set of goods is generally called a "Bin Packing Problem (BPP)". With regard to the Bin Packing Problem, it is well known that to find an optimum solution within a practical time is extremely difficult. A "First-Fit-Decrease (FFD) algorithm" is known as an approximate solution algorithm (refer to "Combinatorial Optimization: Theory and Algorithms", written by B. Korte and J. Vygen, translated by Takao Asano et al., Springer-Verlag Tokyo, Nov. 3, 2005, pp. 470-472).
A load balancing technique with respect to a parallel computer is described in Japanese Laid Open Patent Application JP-A-Heisei, 10-27167. The parallel computer consists of a plurality of computers and executes a parallel program composed of a plurality of constitutive programs. When the plurality of constitutive programs are allocated to the plurality of computers, the load balancing is performed in consideration of the load applied to the computer by the constitutive program itself. More specifically, a history collecting program collects resource utilization of each constitutive program. Moreover, a scheduler refers to current resource utilization of each computer and allocates a constitutive program with the larger resource utilization to a computer with the smaller current resource utilization. In other words, the scheduler allocates processing with a heavier load to a computer with a larger available capacity.

Server migration planning system and server migration planning method


A metallic bellows is manufactured by a first step of bulging a straight raw pipe into a primary formed body having formed on a periphery thereof a corrugated bellows section, and a second step of subjecting at least one of crest portions and trough portions of the bellows section of the primary formed body to roll machining by means of a pair of forming rolls.

1. Technical Field
The present invention relates to a method of manufacturing a metallic bellows and to an apparatus for manufacturing a metallic bellows. It relates, in particular, to a method of, and an apparatus for, manufacturing a metallic bellows which is used in a flexible tube to be interposed in an exhaust pipe for a vehicle such as a motor vehicle.
2. Related Art
Generally, a flexible tube using a metallic bellows is interposed on the way to outlet of an exhaust pipe of a vehicle such as a motor vehicle. This flexible tube serves the purpose of absorbing the vibrations from an engine of the motor vehicle, thereby preventing the vibrations from being transmitted to such a part as a muffler on a downstream side of the exhaust system. This kind of metallic bellows is conventionally known to be manufactured in the following method.
Specifically, both end portions of a raw pipe are fitted into a pair of upper and lower end dies. A plurality of intermediate annular dies are interposed at an equal interval from one another between the end dies. Thereafter, in a state in which both ends of the raw pipe are hermetically sealed, there is performed an operation of forming or machining known by the name of bulging which makes use of fluid pressure such as hydraulic pressure or a suitable deformable pressure medium such as urethane rubber, and the like. In this manner, the raw pipe is expanded from the inner side and is also swelled at the portions which form crest (or mountain) portions. Then, the end dies are respectively moved toward each other to thereby perform compression-forming until the intermediate annular dies are brought into close contact with one another. A metallic bellows is thus manufactured. JP-A-1249/1997 is an example of relevant prior art; see for example the description of the prior art.
In the above-described example, the pressure is applied from the inside at the time of bulging to thereby radially swell the portions which form the crest portions of the bellows. As a consequence, there is a problem in that the plate thickness at the crest portions becomes smaller than that at trough (valley) portions, thereby resulting in nonuniform plate thicknesses at the bellows section. Further, there is also another problem in that the shapes of the crest portions and the trough portions are unstable (i.e., the shapes of the U-shaped end portions of the crest portions and the trough portions become irregular).
The spring constant of a metallic bellows can be made smaller by reducing the plate thicknesses at the crest portions and the trough portions of the bellows section. However, in the manufacturing method as described above in which there occurs a difference in plate thicknesses between the crest portions and the trough portions of the bellows section, there is a limit to an attempt to minimize the plate thicknesses. In particular, in an example in which the raw pipe is manufactured with a sheet of metallic plate which is die-cut (or stamped) into a predetermined shape and the free ends thereof are then joined together for welding them together, the welded joint is likely to be damaged. Therefore, it was difficult to reduce the thicknesses at the crest portions and the trough portions of the bellows section. It may then be considered to make the spring constant smaller by increasing the axial length of the bellows section or by enlarging the distances between the respective adjoining crest portions and the trough portions at the bellows section. However, this solution has a problem in that the flexible tube becomes larger in size and weight.

Method of, and apparatus for, manufacturing metallic bellows


There is provided a pressure-sensitive adhesive composition for optical films, which is excellent in heat resistance, weathering resistance and bleed resistance, which has an excellent balance of pressure-sensitive adhesion properties, such as adhesive strength, cohesive force and tack, the tack of which can be controlled, which is excellent in initial reworkability when it is used for applying an optical film to an adherend or applying a protective film to an optical film, and which further exhibits excellent adhesive durability by virtue of rise of adhesive strength when such a film as above in the applied state is kept over a long period of time after application or especially when the film in the applied state is exposed to high temperatures or moist heat. A pressure-sensitive adhesive composition containing a specific acrylic diblock copolymer (I) and a specific acrylic triblock copolymer (II) in a specific proportion and a pressure-sensitive adhesive for optical films using the pressure-sensitive adhesive composition as a base are produced.

It has been known in the past that acrylic block copolymers or acrylic block copolymer compositions are used for pressure-sensitive adhesives. For example, a composition comprising a specific block copolymer having a structure represented by the general formula: -[a1]-[b]-[a2] in the polymer main chain and a diblock copolymer containing at least one (meth)acrylic acid alkyl ester polymer block is excellent not only in various pressure-sensitive adhesion properties such as holding power at high temperatures but also in heat resistance, weathering resistance and hot-melt coating properties and is preferable as a pressure-sensitive adhesive (particularly, hot-melt type pressure-sensitive adhesive) for obtaining pressure-sensitive adhesive sheets and pressure-sensitive adhesive tapes (see patent literature 1).
It is disclosed that a diblock copolymer, which is represented by the general formula: X-Y (in this formula, X is a polymer block mainly constituted of a methacrylic acid alkyl ester unit having an alkyl group of 1 to 4 carbon atoms or an alkyl group having a cyclic structure, and Y is a polymer block mainly constituted of an acrylic acid alkyl ester unit having an alkyl group of 1 to 20 carbon atoms and/or a methacrylic acid alkyl ester unit having an alkyl group of 5 to 20 carbon atoms) and in which the weight-average molecular weight (Mw) of the polymer block X is 1,000 to 8,000 and the ratio of the mass of the polymer block X to the mass of the polymer block Y, that is, X/Y mass ratio, is in the range of 1/99 to 10/90, is useful for obtaining an acrylic pressure-sensitive adhesive that is excellent not only in heat resistance, weathering resistance and various pressure-sensitive adhesion properties but also in hot-melt coating properties (see patent literature 2).
It is disclosed that by blending a block copolymer which has in a molecule at least an acrylic triblock structure wherein one or two acrylic acid ester-based polymer blocks and two or one (meth)acrylic acid ester-based polymer block having a different structure are bonded and which has a weight-average molecular weight (Mw) of not less than 120,000 and a molecular weight distribution of less than 1.5, with a diblock copolymer in which one acrylic acid ester-based polymer block and one (meth)acrylic acid ester-based polymer block having a different structure are bonded and which has a molecular weight distribution of less than 1.5, in a specific proportion, an acrylic block copolymer composition excellent in heat resistance, weathering resistance, bleed resistance, hot-melt properties, melt coating properties, and various pressure-sensitive adhesion properties, such as adhesive strength, cohesive force and tack, is obtained. It is described that various pressure-sensitive adhesion properties are further improved by setting the content of the (meth)acrylic acid ester-based polymer block in the block copolymer constituting the acrylic block copolymer composition to 5 to 22% by mass or by setting the weight-average molecular weight (Mw) of the block copolymer to not less than 150,000 (see patent literature 3).
However, it has not been specifically studied to apply the pressure-sensitive adhesive compositions disclosed in the above patent literatures 1 to 3 to pressure-sensitive adhesion type optical films. With regard to properties of solution type pressure-sensitive adhesives containing acrylic triblock copolymer, anything has not been mentioned at all.
On the other hand, pressure-sensitive adhesives for optical films are used for applying optical films such as polarizing plates and retardation films to liquid crystal panels or applying plural optical films to one another to laminate them or applying protective films to optical films.
In particular, the pressure-sensitive adhesives for optical films are required to have excellent transparency in addition to excellent performance balance as pressure-sensitive adhesives, and besides, they are required to be improved in reworkability, heat resistance, durability, etc.
Specifically, the pressure-sensitive adhesives for optical films are required to have not only transparency but also excellent optical isotropy (no birefringence) in order that the functions of optical films should not be impaired.
In the application of an optical film, an optical film or a protective film once applied is sometimes peeled off and applied again if wrinkles, bubbles, inclusion of foreign matters, deviation of application position, or the like occurs, or after peeling of the optical film, an expensive liquid crystal panel is sometimes recovered and recycled. From such viewpoints, the pressure-sensitive adhesives for optical films are required to have initial reworkability such that there is no adhesive transfer in the process for producing an image display device such as a display, peeling can be carried out with proper peel strength, and re-application is possible.
Further, the pressure-sensitive adhesives for optical films are required to have high durability such that even if the pressure-sensitive adhesive is heated or exposed to moist heat after application of an optical film and before actual use of the optical film, the pressure-sensitive adhesive does not undergo foaming or does not cause peeling of the film from an adherend.
A member comprising an optical film, a base and a pressure-sensitive adhesive layer containing an acrylic block copolymer is known (see patent literature 4). In this literature, however, initial reworkability necessary for pressure-sensitive adhesives for optical films has not been studied, though an effect on inhibiting ply separation and foaming in the pressure-sensitive adhesive layer has been studied in the case where the base is a gas releasing base such as polycarbonate or poly(methylmethacrylate).
Under such circumstances as above, the present inventors have developed a non-chemical crosslinking type pressure-sensitive adhesive for optical films containing a specific acrylic triblock copolymer as a main component, and previously applied for a patent (see patent literature 5). This non-chemical crosslinking type pressure-sensitive adhesive for optical films is free from a problem of variability in pressure-sensitive adhesion performance due to uneven crosslinking, exhibits good cohesive force, is excellent in initial reworkability, pressure-sensitive adhesion properties, heat resistance, durability, etc. and is useful as a pressure-sensitive adhesive for usual optical films. However, even this non-crosslinking type pressure-sensitive adhesive does not have sufficient initial reworkability and durability in some cases.

Pressure-sensitive adhesive composition for optical films and pressure-sensitive adhesion type optical film


An investment casting shell substrate sensor method and apparatus comprising a hollow probe 10 having an aperture 30, the aperture 30 covered by a water proof breathable membrane (WPBM) 20 that is constructed and arranged to repel liquid from entering the aperture 30, while remaining permeable so as to allow vapor and air to pass through the aperture 30, thereby creating a liquid free internal void 50 within the hollow probe 10 that receives a sensor 40 for measuring the conditions (i.e. temperature and humidity) within the internal void 50, which are accurately indicative of the conditions at the shell substrate at the aperture 30 location. The disclosed sensor assembly provides target specific information at selected substrates within the shell real time, during the shell building process.

Investment casting is an ancient process for forming metal parts by pouring molten metals or alloys into ceramic molds, referred to in the art as shells. The shells initially are formed around wax patterns, and after shelling the wax patterns are melted out leaving an internal void that is shaped and having detail of the desired part. The molten metal or alloy is poured into the internal void of the shell, then cools, thereby solidifying into the desired shape and detail of the part. After the metal or alloy has cooled and solidified, the shell is removed revealing the desired part.
Investment casting shells start out as a wax part that is matching the shape, size and detail of the desired article. The wax part is typically dipped into an aqueous ceramic slurry, coated with sand, and then dried before reiterating until the requisite thickness of the shell is obtained. The shell drying environment varies by foundry as temperature control, relative humidity management, and air movement are employed to manage and control the drying of the shell.
Critical care is taken in drying each dip layer from face coat until seal coat, as soak back from later dip coats effect the moisture level of the inner coats which may negatively impact shell strength. Adequate drying is necessary to ensure the strength of the shell and the integrity of detail of the desired article. A 'too wet' section of the interior shell substrate may cause soak back resulting in structural failure or loss of necessary article detail of the shell. A 'too dry' section of the interior shell may cause cracking or splitting resulting in failures during the article pouring process, or defects in the finished article.
After the shell building process is complete, wax is melted out of the shell leaving an internal void within the ceramic shell exacting the shape, size, and detail of the desired article. This wax removal may be performed via a number of methods including an autoclave or flash-fire dewax process. After the wax is melted out of the shell, the shells are inspected for structural failures, often times the noted failures are repaired before the shell is moved to the foundry, that is if the structural defects are discovered
Prior to pouring molten metal or alloy into the internal shell void, the shell is inspected, repaired as needed, and ultimately is placed into an oven. The purpose of this 'oven' step is to burnout any organic materials, form high temperature ceramic bonds and to heat the shell to a temperature which will allow the molten metal or alloy to completely fill-out the detail prior to solidifying. Once the shell is heat cured and maintained at the desired temperature for the requisite time, the molten metal or alloy is poured, filling the internal shell void completely.
The metal or alloy is allowed to cool within the shell taking on the shape and full detail of the original wax part. After adequate cooling, the shell is removed revealing a metal casting in exacting shape and detail as the wax part. The cast part is cut off the runner and processed to the required specifications.
During each of the described steps in the investment casting process a number of variables impact the subsequent steps that ultimately affect finished casting article quality. In an effort to assure quality control, repeatability, and effectuate an economy in production, it is critical to identify the key variables and establish operating protocols to manage the same.
Having good process control in the shell room is critical in making high quality consistent shells that produce desired casting parts. Some of key variables that need to be monitored and controlled include, but are not limited to pH, SiO2 content, % polymer, slurry viscosity, shell drying, shell room temperature and relative humidity. Variations in any of these can impact the quality of the finished part.
Shell drying is likely one of the most critical variables that has proved difficult to accurately monitor and therefore control. Historically, it has been challenging to determine a reliable method or apparatus that provides real time information regarding variations in the temperature and moisture level within the shell substrates during the dipping and drying process. As discussed above, inadequate drying can cause casting defects such as excess metal, finning or even foundry run-outs. Excessive drying can result in longer processing time, in addition to surface-related casting defects such as cracks and rat-tailing. Knowing the temperature and level of dryness at the interior shell surface or within the substrates of the shell itself would provide valuable insight as to how to adjust or fine tune the dipping and drying processes to maximize efficiencies while maintaining quality control.
Prior to this invention, shell moisture or dryness monitoring had four accepted methods; visual indicator, weight loss studies, temperature and conductivity. The first two methods provide information as to the average dryness of the shell in it's entirety, with minimal to no accurate target specific data. The latter methods, temperature and conductivity can provide data at a specific location of a shell, however, both methods are limited. Measuring temperature and then inferring an estimated dryness in the internal passages of a mold can result in erroneous data if there isn't sufficient air movement to remove the moisture-saturated air. Conductivity can be an effective method to measure moisture content of the mold in a specific location, however, it is difficult to locate the probes such that substrate specific or area specific information can be measured.
While each of the described methods and apparatus tests for general shell drying, not one of the previous methods or apparatus provide accurate, reliable and repeatable testing for the specific substrates and areas most difficult to dry, including the inner passage ways, blind holes and slots. Also, later dip iterations may cause excess moisture to be absorbed into the drying shell substrates, thereby wicking back towards the wax part, creating a hidden wet area within the inner shell substrates that if not dried adequately, will cause a failure or defect.
The prior art is replete with control apparatus and methods relating to the ceramic slurry viscosity, drying methods of the shell between slurry dips, robotic dipping apparatus controlled by microprocessor, wax formulas, and exterior shell monitoring to forecast internal shell dryness. However, nothing in the prior art teaches or suggests a method or apparatus for real time monitoring and data recordation of the environmental conditions at specific target location at the shell interior, or within the shell substrates during both the slurry dipping process or shell drying periods.

Method and apparatus for measuring and recording real time environmental conditions at target shell locations during the shell building process


An electricity-producing shoe comprises a shoe body including an electricity-producing module and an electricity generator mounted therein. The electricity-producing module includes a rack, first and second gears, and a spring buffer that mounts between the first and second gears. The first and second gears are engaged with the rack and an axial gear of the electricity generator, respectively. The electricity generator has an electricity output terminal connected to an electric device of the shoe body. As a result, the rack drives the first gear and the second gear drives the axial gear of the electricity generator by means of normal stepping motion of walking for producing electric power and thereby supplying the electric power for the electric device.

The major objective of shoe is to protect the foot during walking and to make the foot comfortable. More recently, the shoe is designedly suitable for various purposes besides having an esthetically desirable appearance. Various shoes that equip with various specific functions are gradually developed. For example, a step-counting shoe can count steps of walking; a light-emitting shoe can show a blinker light; an air cushion shoe can provide the shock-absorbing function; and an anion shoe that deodorizes and sterilizes is even invented.
However, these specific shoes must be provided with power-supplying units in order to implement their specific functions. These conventional power-supplying units mostly are composed of batteries. But, every battery has its own lifetime. When its electric power is exhausted, this battery must be replaced with a new one so as to maintain normal working of electric device.
Moreover, every battery such as dry battery, mercury battery, or lithium battery is harmful to the ecosystem of the earth. Therefore, the environmental groups always appeal to people for reducing usage amounts of batteries. The major drawback of the conventional shoes with specific functions apparently consists in that they cannot work without batteries.
In view of the aforementioned conventional deficiency, the present inventor makes a diligent study to provide the consumer with an electricity-producing shoe capable of producing electric power by use of gravity drop formed naturally during stepping motion of walking in accordance with the motive of the present invention.


An apparatus, a carrier medium carrying computer readable code to implement a method, and a method for searching for a plurality of patterns definable by complex expressions, and further, for efficiently generating data for such searching. One method includes accepting or determining a plurality of state machines for searching for a plurality of patterns, merging the state machines to form a merged state machine, and storing a data structure describing the merged state machine, including state data on the states of the merged state machine. The method is such that pattern matching logic reading state data and accepting a sequence of inputs can search the input sequence for the plurality of patterns.

The Need for Pattern Matching and Searching in Networks
Computer networks, such as local area networks, wide area networks, and internetworks such as the Internet are common. As organizations adopt and increase network usage, the number of applications and demands placed upon network functionality increases. Accordingly, much effort in the art has been devoted to producing more efficient ways to process the ever-increasing amount of information transmitted over computer networks.
Data that is transmitted over a network is typically broken up into one or more discrete packets of data. Nodes of a computer network, e.g., routers, switches, firewalls, aggregators, and so forth, perform complex data analysis and management on these packets. It is these network nodes that typically have increasing demands placed upon them, and that require new inventive methods to keep up with the ever-increasing flow of network traffic.
One operation required in such nodes is the searching for specific patterns in the packets.
Network data analysis often involves scanning, processing or mining network data for useful information. For the simplest analysis problems, the standards according to which networks are designed provide a useful description, e.g., a map, for some information contained in network traffic. For example, many methods have been developed to scan network traffic for information by looking up packet headers, e.g., MAC addresses, IP addresses, TCP port numbers, and so forth. As a result, a number of early network analysis methods and products based thereon have been developed using simple, fixed-length pattern scanning techniques.
More complex network analysis problems require processing a plurality of packets that are related to each other. Such analysis is typically required when one wishes to analyze traffic at a higher level. For example, higher level network traffic analysis is required to perform packet classification, protocol analysis, URL address lookup, payload content inspection, virus signature scanning, intrusion detection, stateful firewall rule matching, load balancer rule matching, and so forth. Further, such higher-level analysis sometimes requires more complicated searching functionality than simple field lookups according to a network standard.
Pattern Matching and Searching Methods
Searching an input, e.g., a network data stream, for a simple sequence of inputs is well known in the art. The inputs in general are called "characters" of an "alphabet." For example, an input may be an octet of the alphabet of all possible octets. Alphabetical characters are used herein to describe inputs only for the sake of explanation, and also because searching for text patterns is common. For example, a simple sequential character-searching problem might be trying to find if and where the sequence "cab" appears in the input "abacab." Some methods of the art for solving such a problem include the Knuth-Morris-Pratt method (D. E Knuth, J. H. Morris Jr., V. R. Pratt: Fast pattern matching in strings, SIAM Journal on Computing, vol. 6, no. 1, pp. 323-350, 1977), the Aho & Corasick method (A. Aho, and B. Corasick: Efficient string matching: An aid to bibliographic search, Commun. the ACM, vol. 18, no. 6, pp. 333-343. 1975), the Rabin-Karp method (Richard Karp and Michael Rabin: Efficient randomized pattern-matching algorithms, IBM J. Res. Develop., vol. 31, no. 2, pp. 249-260, 1987), and the Boyer-Moore method (R. S. Boyer, J. S. Moore: A fast string searching algorithm, Comm. ACM, vol. 20, pp. 62-72, 1977).
Searching an input for a more complicated pattern of inputs, e.g., pattern matching, is also well known in the art. For example, one may wish to find all string sequences starting with "a" followed by at least one "b" in the input "cbaabbcaba." Such a problem can be more generally described as finding certain input sequences, e.g., a pattern, in another sequence of inputs.
Regular Expressions
Pattern matching typically involves the use of a pattern description language, e.g., a grammar, to describe the pattern and then a method to transform an expression in the language to a state machine that will run with an input that may contain the pattern. For example, one popular pattern description language is known as the language of Regular Expressions. See, for example, Jeffrey E. F. Friedl, Andy Oram, Mastering Regular Expressions, 2nd Edition, O'Reilly, 2002. See also the online guide at called "Regular Expressions", part of The Single UNIX® Specification, Version 2, from The Open Group, available at http://www.opengroup.org/onlinepubs/007908799/xbd/re.html (valid on Oct. 17, 2004).
While those skilled in the art would be familiar with regular expressions, a brief introduction is provided herewith for completeness. Regular expressions are useful because they can express complicated patterns using only a relatively small number of characters. For example all string sequences starting with "a" followed by at least one "b" can be represented as "ab+." See Table 1 for a short list of some regular expression rules and Table 2 for some examples of regular expressions.
TABLE 1Some Regular Expression Rules.Match any character*Match the preceding occurring at least one time,or no times+Match the preceding 1 or more timesA|BMatch A or B(A)Match just A (often used in conjunction with |)[list]Match a character, only if it is in list[{circumflex over ( )}list]Match a character, only if it is not in list
TABLE 2Some Regular Expression Examples.*abcMatches "89abc", "abc" but not "89abd"a(b|c)Matches "ab", "ac", but not "ax"A*B+Matches "AABB", "AB", but not "AA"b[0,5]cMatches "b0c", "b4c", but not "b9c" or "bc"State Machines and Finite Automata for Regular Expressions
It is well known to those in the art to use state machines to search for patterns, e.g., patterns expressed by regular expressions. Those in the art also know that finite automata theory can be used to abstractly describe state machines that search for patterns expressed by regular expressions. According to finite automata theory, a state machine is a limited abstract computing device that finds in an input the pattern(s) described by the state machine description. A state machine includes a finite set of states and an alphabet, e.g., a set of one or more inputs. There is one start state, e.g., state zero, and at least one final state defined as a state that produces a "hit," called a hit state herein, and meaning that a pattern was found. Each state has one or more paths that point to any state of the set of states, e.g., another state or the same state. Each path is associated with an input from the alphabet of inputs.
When processing an input, e.g., a sequence of at least one input from the alphabet of possible inputs, a state machine starts in the start state. As the state machine reads each input, it moves to the next state defined by the path associated with the input. By some conventions, if there is no path associated with the input, the state machine moves to a special error state that indicates, e.g., that the pattern represented by the state machine does not exist in the sequence of inputs. By other conventions, every state must have a path associated with every possible input of the alphabet of inputs. If the state machine moves to a hit state, then this indicates a match, e.g., the pattern represented by the state machine description exists in the input. If the state machine reaches the end of the sequence of inputs without moving to a final state, then this indicates no match, e.g., the pattern represented by the state machine description does not exist in the sequence of inputs.
Deterministic Finite Automata (DFAs) and Non-Deterministic Finite Automata (NFAs)
It is known in finite automata theory to classify a state machine into one of two general classifications: deterministic finite automata (DFAs) and non-deterministic finite automata (NFAs). DFAs are state machines wherein each path of a given state is uniquely associated with an input of the alphabet. In other words, for a particular state, there cannot be two paths associated with the same input. Thus, for DFAs, the computational time complexity for processing an input has an upper bound, e.g., the computational time complexity is O(n) where n is the length of the sequence of inputs. Although generating a DFA from a regular expression, e.g., compiling a DFA from a regular expression requires additional computation, using the resulting DFA state machine with any input is in general very efficient.
NFAs are state machines that differ from DFAs in several ways. First, NFAs have no uniqueness restriction applied to paths, e.g., for any particular state, two or more paths may be associated with the same input from the alphabet of inputs, i.e., an NFA can have multiple paths from the same state, each path associated with the same input. Furthermore, NFAs allow what are called "null" paths or transitions. Such paths are represented as being associated with a special character ε that represents such a "null" path. A null path does not consume an input character; it represents a spontaneous transition without consuming an input. Additionally, when an NFA is used to process an input, a particular state that has null and non-null paths can transition via any one of the null paths, or via any one of the non-null paths associated with the current input. That is, when in a first state and processing an input for which there are a plurality of paths, if a particular chosen path does not lead to a match state, the NFA returns to that first, i.e. the previous state, and tries another possible path associated with that input. Thus, for NFAs, the computational time complexity for processing an input can be exponential, e.g., the computational time complexity can be O(cn) where n is the number of inputs and c an integer greater than 1. Typically, generating an NFA description for a pattern yields a state machine with a smaller set of states than generating a DFA description from the same pattern. However, using that NFA as a state machine for a provided input leads to unpredictable computational time complexity.
Finite automata theory is well known in the art, and as a result, a number of methods have been developed and are known to transform a NFA into a DFA and a DFA into a NFA. Methods also are known for transforming a pattern such as a regular expression into a NFA for matching the pattern, and into a DFA for matching the pattern.
Overview of Some Needs in the Art
As more and more networks are used, as the speed of such networks become higher and higher, and as networks become more and more complex, there is a general need in the art for processing network traffic more efficiently. When searching for patterns, e.g., patterns described by a pattern language such as a regular expression, there is a need in the art for managing computer implemented state machines in an efficient manner usable for such searching.
For example, as regular expressions become more complicated (more complex), the number of states in a DFA or NFA can be rather large. There is a need in the art for methods to efficiently represent the states of a finite state machine that can be used for searching for a pattern describable by a regular expression. For example, there is a need in the art to represent such states and state transition information of a state machine in a compressed manner that does not require much memory. There also is a need in the art to represent such state and state transition information in a manner that provides for rapidly reading the information from memory or storage so that searching can be carried out rapidly, e.g., in real time for relatively fast networks.
While how to design a state machine that can search ("match") patterns describable by a single regular expression is known, there is a need in the art for a state machine and for a search method that can simultaneously search for a plurality of regular expressions.
It is desirable to be able to manage both patterns that are known a priori, e.g., patterns for well known protocols, for known packet formats, for known viruses, for known intrusion signatures, and so forth, and also patterns still to be discovered, e.g., patterns for new protocol and packet formats, for firewall security rules, for quality of service ("QoS") policies, for newly discovered viruses or intrusion signatures, and so forth. There is thus a need in the art to efficiently manage, e.g., iteratively manage patterns as they are developed in a pattern database in a scalable manner.
Thus, there is a need in the art for a method and apparatus to efficiently generate, e.g., compile a set of at least one pattern into a set of at least one state machines that can be processed in O(n) computational time complexity for an input of size n. Further, there is a need in the art to efficiently transform a set of at least one state machines into a pattern database usable for processing input to generate an output of possible pattern matches.

Simultaneously searching for a plurality of patterns definable by complex expressions, and efficiently generating data for such searching


A system and method are provided for regulating incoming traffic to a web site to prevent overload conditions from occurring. The system comprises a capacity determination unit for determining if a web site has additional capacity and a notification unit for notifying customers if no capacity is available. A scheduling processor provides a customer with scheduling options. When the web site has sufficient capacity, a redirect unit redirects the customer to the web site.

In recent years, many e-commerce businesses have suffered from managing the problem of success. The growth of e-commerce has caused web site proprietors to have frequent occasion to reevaluate their hardware and software needs for their web sites. Frequently, a web site proprietor faces the realization that an initial amount of software and hardware allocated to a web site is insufficient to accommodate a number of concurrent users accessing the web site (i.e., the "load" on the web site). Additionally, response times for accessing the web site, performing certain activities within the web site, and retrieving desired information from the web site may become so slow that a user of the web site exits the web site due to the slow response time. On extreme overload conditions, some customers will receive "server not available" errors and will not be able to get access. It is additionally possible that customers could be dropped in the middle of a transaction. Ultimately, the entire web site could fail under the load. Examples of sites experiencing overload problems include Amazon.com and Barnes & Noble, which experienced overload during the release of the new Stephen King novel. Additionally, the Victoria's Secret web site failed completely during its first fashion show.
Web site proprietors, such as Internet "start-up companies," are initially uncertain as to the loads their web sites will be required to handle. Such web sites may initially be developed on a small scale, and the web site proprietors may have an intention of expanding the web sites in the future. However, if a web site is selling products or services which are in great demand or the web site offers incentives to users who access the web site in order to increase the number of users of the web site, or the web site is actively engaged in advertising and publicizing the products or services sold via the web site, the web site often ends up becoming quickly overburdened by a large number of concurrent users. The proprietor of the web site may not be able to respond quickly enough by adding hardware and software to the web site to address the large number of concurrent users. Consequently, the web site may experience technical difficulties such as "crashes" or slow response times because it was not designed to handle the traffic level loads. Such technical difficulties frequently cause consumer dissatisfaction. The web site proprietor may lose potential customers while trying to redesign the web site to meet the large volume of concurrent users.
In view of the foregoing, it would be desirable to provide a technique for managing web site traffic which overcomes the above-described inadequacies and shortcomings. In traditional businesses, companies are able to limit the number of customers they service through limiting physical access to stores or placing customers on hold on phone lines. A system and/or method is needed to avoid web site technical difficulties, such as web site crashes and slow response times, among other difficulties, by limiting the number of concurrent users that can access the web site and notifying customers that web site access is not currently available.

System and method for regulating web site access


A security system for detecting and signalling the presence of abnormal security or hazardous conditions, such as unauthorized entry, glass breakage, fire, smoke, high water level, in individual units, such as a boat, a recreational vehicle, an automobile, which are located or stored in a given security area.. The security system comprises sensor units which, when actuated, transmit coded signals through the atmosphere which identifies each sensor unit and the individual unit on which it is located. A receiver on the individual unit recognizes only the coded signals from sensor units which are on the same individual unit as the receiver. A coded output signal is provided to a slave transmitter on the individual unit which identifies the particular sensor unit which was actuated. The slave transmitter provides a coded transmission signal to a local security station which identifies the particular sensor unit which was actuated and the individual unit where the actuated sensor unit resides. The local security station activates an alarm and dials a sequence of telephone numbers to provide a verbal alarm.

In recent times the theft of individual units such as boats, recreational vehicles, trailers, automobiles, etc. as well as items from boats, recreational vehicles, trailers, automobiles, apartments, etc. has grown to alarming proportions.
Several approaches have been adopted in an attempt to combat theft of items from individual units but most if not all approaches have required the owner to be in the area to monitor the system of his own individual unit. When the boat owner docks his boat in the boat slip at the marina and goes home, he is not in the area to monitor his own system on his individual unit or boat. This is also true when (1) the boat owner stores his boat in the dry stacks at the marina in the off season, (2) when the owner of the recreational vehicle or trailer stores his recreational vehicle or trailer in a trailer storage area in the off season, (3) when the owner of an automobile delivers his car to the storage lot of a car mover for a move across country, (4) when the renter of an apartment is gone from his apartment, (5) when the renter of a storage area stores items in storage areas such as individual mini-warehouses, etc. In fact, this is true whenever individual unite are congregated together in a designated or given area.
This invention deals with these as well as related problems and provides a security alarm system which detects and signals the occurrence of a predetermined event with regard to the individual unit, such as unauthorized entry, glass breakage, fire, smoke, unauthorized movement, low battery, high water level in the bilge of a boat, activation of a panic button, via digitally coded messages to a central station which monitors all the individual units in the designated or given area.


A group advertisement method in a SIP (Session Initiation Protocol) based message service, and a PT client device are discussed. According to an embodiment, the method includes receiving, by a PT server, a request to send a group advertisement message for a specific PT group from a requesting PT client; determining, by the PT server, if the specific PT group is a restricted chat group or a pre-arranged group; determining, by the PT server, if the requesting PT client is allowed to send a group advertisement based on a PT group document associated with the specific PT group; and selectively transmitting, by the PT server, the group advertisement message to at least one member of the specific PT group based on results of the determining steps.

1. Field of the Invention
The present invention relates to a session based service, and more particularly, a group advertisement method in a SIP (Session Initiation Protocol) based message service.
2. Discussion of the Related Art
In general, a PT (Push-To) service, which is intended to provide rapid communications for service providers and mobile communication users, is a communication service in which one client transmits media data (e.g., talk burst) to one or more other clients with which a session has been established. A PT service can be a PoC (Push-to-talk over Cellular) service for transmission of voice (audio), a PTV (Push To View) service for transmission of pictures (video), or a PTD (Push To Data) service for transmission of data.
The PT service allows communication with a single recipient (1-to-1) or between groups of recipients as in a group chat session (1-to-many), and uses a session initiation protocol (SIP) to establish a session.
In the PT service, one PT client can invite clients or groups, to which clients belong, to a PT session. That is, a particular PT client selects one or more other PT clients to Invite them to the PT session. The session is then established among these PT clients. Accordingly, media data is communicated between the session-established PT clients.
The PT service provides "group advertisement". The group advertisement denotes that one PT group designator designates a particular PT group to inform other PT clients of the existence of the PT group for use. For instance, a particular PT client may advertise (inform) about an address of a PT group (e.g., group name) to the members of the PT group, so that the PT group members can use the PT group address to communicate with each other.
The designated PT group can be divided into an unrestricted chat PT group in which a group advertisement is allowed (accepted) for every PT client, and a restricted chat PT group in which a group advertisement is allowed only for PT group members. The chat PT groups generally are generally established at a server side, e.g., by an operator or an administer, so end-users such as customers can simply join such chat groups. Here, the designator would be the operator or the administrator. Another example of the designated PT group is a pre-arranged PT group which is generally established by an individual end-user. For instance, a user of a terminal can create his own PT group composed of his family and friends as members. Here, the designator is the user who created such pre-arranged PT group.
Therefore, generally the PT group designator registers a PT group document for the corresponding PT group in an XDM (XML Database Management) server. Generally the PT group document identifies the group name/address and the members belonging to the group. A controlling PT server performing a control function can process a group advertisement request of a PT client via a SIP message based on the PT group document.
However, the PT group document according to the related art does not specify any rule or condition regarding the group advertisement, because PT service provides have not made advertising rules for the group advertisement yet. As a result, in the related art, every PT user has been unconditionally allowed to perform a group advertisement with respect to a PT group designated by the PT group designator, which causes frequent invitations to all the group members due to the over-exposure of group and group member addresses. Since any appropriate advertising rule has not be provided for the group advertisement in the related art, the PT group designator can not stably maintain and operate the PT group designated by itself. As a result, a group advertisement in the related art is performed many times and unnecessarily, without the consideration of any relevant factor such as privacy, etc. Also, the related art has a problem in that information related to the corresponding PT group to which participants belong is exposed regardless of their intentions.

Group advertisement method in SIP based message service


I improve the impact shock resistance of bonds between composite elements by including Z-pin reinforcement. I prepare stubbled composite structure by using peel plys over the appropriate surface of the composite during pin insertion using conventional processes. I then use the stubbled composite structure with padups, as necessary, to produce the Z-pin reinforced joint or bond between composite elements using any of adhesive bonding, cocuring, or thermoplastic welding.

The use of composites in primary structure in aerospace applications is limited today because of the relatively high cost. A significant contribution to the total cost is the assembly cost where the precured composite elements are assembled, drilled, and fastened. The necessary design for mechanical fastening complicates the structure, especially in thin sections, because of the need for access to both sides of the bond line.
While composites might be adhesively bonded, cocured, or welded, these connecting processes generally produce bonds that rely upon the resin matrix for strength. The bond line lacks any reinforcing material to help with load transfer. These bonds generally have modest strength, and are susceptible to disbonding with shock impact or other "out of plane" forces affecting the assembly. Such forces often arise in environments prone to vibration. The present invention is a method to introduce Z-pin reinforcement along the bond line especially in fastenerless composite assemblies.
1. Composite Manufacturing
Fiber-reinforced organic resin matrix composites have a high strength-to-weight ratio (specific strength) or a high stiffness-to-weight ratio (specific stiffness) and desirable fatigue characteristics that make them attractive as replacements for metal in aerospace applications where weight, strength, or fatigue is critical. Thermoplastic or thermoset organic resin composites, would be more economical with improved manufacturing processes that reduced touch labor and forming time.
Prepregs combine continuous, woven, or chopped reinforcing fibers with an uncured matrix resin, and usually comprise fiber sheets with a thin film of the matrix. Sheets of prepreg generally are placed (laid-up) by hand or with fiber placement machines directly upon a tool or die having a forming surface contoured to the desired shape of the completed part or are laid-up in a flat sheet which is then draped and formed over the tool or die to the contour of the tool. Then the resin in the prepreg lay up is consolidated (i.e. pressed to remove any air, gas, or vapor) and cured (i.e., chemically converted to its final form usually through chain-extension or fused into a single piece) in a vacuum bag process in an autoclave (i.e., a pressure oven) to complete the part.
The tools or dies for composite processing typically are formed to close dimensional tolerances. They are massive, must be heated along with the workpiece, and must be cooled prior to removing the completed part. The delay caused to heat and to cool the mass of the tools adds substantially to the overall time necessary to fabricate each part. These delays are especially significant when the manufacturing run is low rate where the dies need to be changed frequently, often after producing only a few parts of each kind. An autoclave has similar limitations; it is a batch operation.
In hot press forming, the prepreg is laid-up to create a preform, which is bagged (if necessary) and placed between matched metal tools that include forming surfaces to define the internal, external, or both mold lines of the completed part. The tools and composite preform are placed within a press and then the tools, press, and preform are heated.
The tooling in autoclave or hot press fabrication is a significant heat sink that consumes substantial energy. Furthermore, the tooling takes significant time to heat the composite material to its consolidation temperature and, after curing the composite, to cool to a temperature at which it is safe to remove the finished composite part.
As described in U.S. Pat. No. 4,657,717 a flat composite prepreg panel was sandwiched between two metal sheets made from a superplastically formable alloy and was formed against a die having a surface precisely contoured to the final shape of the part.
Attempts have been made to reduce composite fabrication times by actively cooling the tools after forming the composite part. These attempts have shortened the time necessary to produce a composite part, but actively cooled tools are expensive and the cycle time for heating and cooling remains so fabrication costs remain high.
Boeing described a process for organic matrix forming and consolidation using induction heating in U.S. Pat. No. 5,530,227. There, prepregs were laid up in a flat sheet and were sandwiched between aluminum susceptor facesheets. The facesheets were susceptible to heating by induction and formed a retort to enclose the prepreg preform. To ensure an inert atmosphere around the composite during curing and to permit withdrawing volatiles and outgassing from around the composite during the consolidation, the facesheets are sealed around their periphery. Such welding unduly increased the preparation time and the cost for part fabrication. It also ruined the facesheets (i.e., prohibited their reuse which added a significant cost penalty to each part fabricated with this approach). So, Boeing described in U.S. Pat. No. 5,599,472 a technique that readily and reliably sealed the retort without the need for welding and permits reuse of the facesheets in certain circumstances. This "bag-and-seal" technique applies to both resin composite and metal processing.
2. Processing in an Induction Press
Boeing dies or tooling for induction processing are ceramic because a ceramic is not susceptible to induction heating and, preferably, is a thermal insulator (i.e., a relatively poor conductor of heat). Ceramic tooling is strengthened and reinforced internally with fiberglass rods or other appropriate reinforcements and externally with metal or other durable strongbacks to permit it to withstand the temperatures and pressures necessary to form, to consolidate, or otherwise to process the composite materials or metals. Ceramic tools cost less to fabricate than metal tools of comparable size and have less thermal mass than metal tooling because they are unaffected by the induction field. Because the ceramic tooling is not susceptible to induction heating, it is possible to embed induction heating elements in the ceramic tooling and to heat the composite or metal retort without significantly heating the tools. Thus, induction heating can reduce the time required and energy consumed to fabricate a part.
While graphite or boron fibers can be heated directly by induction, most organic matrix composites require a susceptor in or adjacent to the composite material preform to achieve the necessary heating for consolidation or forming. The susceptor is heated inductively and transfers its heat principally through conduction to the preform or workpiece that usually is sealed within the susceptor retort. Enclosed in the metal retort, the workpiece does not experience the oscillating magnetic field which instead is absorbed in the retort sheets. Heating is by conduction from the retort to the workpiece.
Induction focuses heating on the retort (and workpiece) and eliminates wasteful, inefficient heat sinks. Because the ceramic tools in the Boeing induction heating workcell do not heat to as high a temperature as the metal tooling of conventional, prior art presses, problems caused by different coefficients of thermal expansion between the tools and the workpiece are reduced. Furthermore, Boeing's induction heating press is energy efficient because significantly higher percentages of input energy go to heating the workpiece than occurs with conventional presses. The reduced thermal mass and ability to focus the heating energy permits us to change the operating temperature rapidly which improves the products we produce. Finally, the shop environment is not heated as significantly from the radiation of the large thermal mass of a conventional press, and is a safer and more pleasant environment for the press operators.
In induction heating for consolidating or forming organic matrix composite materials, Boeing generally places a thermoplastic organic matrix composite preform of PEEK or ULTEM, for example, within the retort. These thermoplastics have a low concentration of residual volatile solvents and are easy to use. The susceptor facesheets of the retort are inductively heated to heat the preform. They apply consolidation and forming pressure to consolidate and, if applicable, to form the preform at its curing temperature. The sealed susceptor sheets form a pressure zone that functions like a conventional vacuum bag processes for resin consolidation. The retort is placed in an induction heating press on the forming surfaces of dies having the desired shape of the molded composite part. After the retort and preform are inductively heated to the desired elevated temperature, differential pressure (while maintaining the vacuum in the pressure zone around the preform) across the retort which functions as a diaphragm in the press forms the preform against the die into the desired shape of the completed composite panel.
The retort often includes three susceptor sheets sealed around their periphery to define two pressure zones. The first pressure zone surrounds the composite panel/preform or metal workpiece and is evacuated and maintained under vacuum. The second pressure zone is pressurized (i.e., flooded with gas) at the appropriate time to help form the composite panel or workpiece. The shared wall of the three layer sandwich that defines the two pressure zones acts as the diaphragm in this situation.
Boeing can perform a wide range of manufacturing operations in its induction heating press. These operations have optimum operating temperatures ranging from about 350.degree. F. (175.degree. C.) to at least about 1850.degree. F. (1010.degree. C.). For each operation, the temperature is held relatively constant for several minutes to several hours. Controlling the input power fed to the induction coil provides temperature control, but a better and simpler way capitalizes on the Curie temperature. By judicious selection of the metal or alloy in the retort's susceptor facesheets, we can avoid excessive heating irrespective of the input power. With improved control and improved temperature uniformity in the workpiece, we produce better products. The method capitalizes on the Curie temperature phenomenon to control the absolute temperature of the workpiece and to obtain substantial thermal uniformity in the workpiece by matching the Curie temperature of the susceptor to the desired temperature of the induction heating operation being performed. This temperature control method is explained in greater detail in U.S. Pat. No. 5,723,849.
3. Thermoplastic Welding
Three major joining technologies exist for aerospace composite structure: mechanical fastening; adhesive bonding; and welding. Both mechanical fastening and adhesive bonding are costly, time consuming assembly steps that introduce excess cost even if the parts that are assembled are fabricated from components produced by an emerging, cost efficient process. Mechanical fastening requires expensive hole locating, drilling, shimming, and fastener installation, while adhesive bonding often requires complicated surface pretreatments.
In contrast, thermoplastic welding, which eliminates fasteners, features the ability to join thermoplastic composite components at high speeds with minimum touch labor and little, if any, pretreatments. In our experience, the welding interlayer (compromising the susceptor and surrounding thermoplastic resin either coating the susceptor or sandwiching it) also can simultaneously take the place of shims required in mechanical fastening. As such, composite welding holds promise to be an affordable joining process. For "welding" a combination of thermoplastic and thermoset composite parts together, the resin that the susceptor melts functions as a hot melt adhesive. If fully realized, thermoplastic-thermoset bonding will further reduce the cost of composite assembly.
There is a large stake in developing a successful welding process. Its advantages versus traditional composite joining methods are:
reduced parts count versus fasteners PA1 minimal surface preparation, in most cases a simple solvent wipe to remove surface contaminants PA1 indefinite shelf life at room temperature PA1 short process cycle time, typically measured in minutes PA1 enhanced joint performance, especially hot/wet and fatigue PA1 permits rapid field repair of composites or other structures.
There is little or no loss of bond strength after prolonged exposure to environmental influences.
U.S. Pat. No. 4,673,450 describes a method to spot weld graphite fiber reinforced PEEK composites using a pair of electrodes After roughening the surfaces of the prefabricated PEEK composites in the region of the bond, Burke placed a PEEK adhesive ply along the bond line, applied a pressure of about 50-100 psi through the electrodes, and heated the embedded graphite fibers by applying a voltage in the range of 20-40 volts at 30-40 amps for approximately 5-10 seconds with the electrodes. Access to both sides of the assembly is required in this process which limits its application.
Prior art disclosing thermoplastic welding with induction heating is illustrated by U.S. Pat. Nos. 3,966,402 and 4,120,712. In these patents, conventional metallic susceptors are used and have a regular pattern of openings of traditional manufacture. Achieving a uniform, controllable temperature in the bond line, which is crucial to preparing a thermoplastic weld of adequate integrity to permit use of welding in aerospace primary structure, is difficult with conventional susceptors.
Thermoplastic welding is a process for forming a fusion bond between two faying thermoplastic faces of two parts. A fusion bond is created when the thermoplastic on the surface of the two thermoplastic composite parts is heated to the melting or softening point and the two surfaces are brought into contact, so that the molten thermoplastic mixes, and the surfaces are held in contact while the thermoplastic cools below the softening temperature.
Simple as thermoplastic welding sounds, it is difficult to perform reliably and repeatably in a real factory on full-scale parts to build a large structure such as an airplane wing box. One difficulty is heating to the bond line properly without overheating the entire structure. It is difficult to achieve intimate contact of the faying surfaces of the two parts at the bond line during heating and cooling despite the normal imperfections in the flatness of composite parts, thermal expansion of the thermoplastic during heating to the softening or melting temperature, flow of the thermoplastic out of the bond line under pressure (i.e., squeeze out), and then contraction of the thermoplastic in the bond line during cooling.
The exponential decay of the strength of magnetic fields dictates that, in induction welding processes, the susceptible structure closest to the induction coil will be the hottest, since it experiences the strongest field. Therefore, it is difficult to obtain adequate heating at the bond line between two graphite or carbon fiber reinforced resin matrix composites relying on the susceptibility of the fibers alone as the source of heating in the assembly. For the inner plies to be hot enough to melt the resin, the outer plies closer to the induction coil and in the stronger magnetic field are too hot. The matrix resin in the entire piece of composite melts. The overheating results in porosity in the product, delamination, and, in some cases, destruction or denaturing of the resin. To avoid overheating of the outer plies and to insure adequate heating of the inner plies, we use a susceptor of significantly higher conductivity than the fibers to peak the heating selectively at the bond line. An electromagnetic induction coil heats a susceptor to melt and cure a thermoplastic resin (also sometimes referred to as an adhesive) to bond the elements of the assembly together.
The current density in the susceptor may be higher at the edges of the susceptor than in the center because of the nonlinearity of the coil, such as occurs when using a cup core induction coil like that described in U.S. Pat. No. 5,313,037. Overheating the edges of the assembly can result in underheating the center, either condition leading to inferior welds because of non-uniform curing. It is necessary to have an open or mesh pattern in the susceptor embedded at the bond line to allow the resin to create the fusion bond between the composite elements of the assembly when the resin heats and melts.
a. Moving Coil Welding Processes
In U.S. Pat. No. 5,500,511, Boeing described a tailored susceptor for approaching the desired temperature uniformity. This susceptor, designed for use with the cup coil of U.S. Pat. No. 5,313,037, relied upon carefully controlling the geometry of openings in the susceptor (both their orientation and their spacing) to distribute the heat evenly. The susceptor used a regular array of anisotropic, diamond shaped openings with a ratio of the length (L) to the width (W) greater than 1 to provide a superior weld by producing a more uniform temperature than obtainable using a susceptor having a similar array, but one where the L/W ratio was one. By changing the length to width ratio (the aspect ratio) of the diamond-shaped openings in the susceptor, they achieved a large difference in the longitudinal and transverse conductivity in the susceptor, and, thereby, tailored the current density within the susceptor. A tailored susceptor having openings with a length (L) to width (W) ratio of 2:1 has a longitudinal conductivity about four times the transverse conductivity. In addition to tailoring the shape of the openings to tailor the susceptor, we altered the current density in regions near the edges by increasing the foil density (i.e., the absolute amount of metal). Increasing the foil density along the edge of the susceptor increased the conductivity along the edge and reduced the current density and the edge heating. Increased foil density was achieved by folding the susceptor to form edge strips of double thickness or by compressing openings near the edge of an otherwise uniform susceptor. These susceptors were difficult to reproduce reliably. Also, their use forced careful placement and alignment to achieve the desired effect.
The tailored susceptor was designed to use with the cup coil of U.S. Pat. No. 5,313,037, where the magnetic field is strongest near the edges because the central pole creates a null at the center. Therefore, the tailored susceptor was designed to counter the higher field at the edges by accommodating the induced current near the edges. The high longitudinal conductivity encouraged induced currents to flow longitudinally.
Boeing's selvaged susceptor (FIGS. 13 & 14) for thermoplastic welding which is described in U.S. Pat. No. 5,508,496 controls the current density pattern during eddy current heating by an induction coil to provide substantially uniform heating to a composite assembly and to insure the strength and integrity of the weld in the completed part. This susceptor is particularly desirable for welding ribs between prior welded spars using an asymmetric induction coil (described in U.S. Pat. No. 5,444,220, which I incorporate by reference). It provides a controllable area of intense, uniform heating, a trailing region with essentially no heating, and a leading region with minor preheating.
Boeing achieved better performance (i.e., more uniform heating) in rib welding by using a selvaged susceptor having edge strips without openings. The resulting susceptor, then, has a center portion with a regular pattern of opening and solid foil edges, which are referred to as selvage edge strips. Embedded in a thermoplastic resin to make a susceptor/resin tape, the susceptor is easy to handle and to use in performing the composite pieces prior to welding. Also, with a selvaged susceptor, the impedance of the central portion should be anisotropic with a lower transverse impedance than the longitudinal impedance. Here, the L/W ratio of diamond shaped openings should be less than or equal to one. With the selvaged susceptor in the region immediately under the asymmetric induction work coil, current flows across the susceptor to the edges where the current density is lowest and the conductivity, highest.
Generally, the selvaged susceptor is somewhat wider than normal so that the selvage edge strips are not in the bond line. Boeing sometimes removes the selvage edge strips after forming the weld, leaving only a perforated susceptor foil in the weld. This foil has a relatively high open area fraction.
Significant effort has been expended in developing inductor and susceptor systems to optimize the heating of the bond line. A difficulty in producing large scale aerospace-quality structures in a production environment is the aspect of the process dealing with the control of the surface contact of the faying surfaces of the two parts to be welded together. This problem involves the timing, intensity, and schedule of heat application so the material at the faying surfaces is brought to and maintained within the proper temperature range for the requisite amount of time for an adequate bond to form. Intimate contact is maintained while the melted or softened material hardens in its bonded condition.
Large scale parts such as wing spars and ribs, and the wing skins that are bonded to the spars and ribs, are typically on the order of 20-30 feet long at present, and potentially can be as much as 100 feet in length when the process is perfected for commercial transport aircraft. Parts of this magnitude are difficult to produce with perfect flatness. Instead, the typical part will have various combinations of surface deviations from perfect flatness, including large scale waviness in the direction of the major length dimension, twist about the longitudinal axis, dishing or sagging of "I" beam flanges, and small scale surface defects such as asperities and depressions. These irregularities interfere with full surface area contact between the faying surfaces of the two parts and actually result in surface contact only at a few "high points" across the intended bond line. Applying pressure to the parts to force the faying surfaces into contact achieves additional surface contact, but full intimate contact is difficult or impossible to achieve in this way. Applying heat to the interface by electrically heating the susceptor in connection with pressure on the parts tends to flatten the irregularities further. Still, the time needed to achieve full intimate contact with the use of heat and pressure is excessive, can result in deformation of the top part, and tends to raise the overall temperature of the "I" beam flanges to the softening point. When softened, they begin to yield or sag under the application of the pressure needed to achieve a good bond.
Boeing's multipass thermoplastic welding process described in U.S. Pat. No. 5,486,684 (which I also incorporate by reference) enables a moving coil welding process to produce continuous or nearly continuous fusion bonds over the full area of the bond line. The result is high strength welds that we produce reliably, repeatably, and with consistent quality. This multipass welding process produces improved low cost, high strength composite assemblies of large scale parts fusion bonded together with consistent quality. It uses a schedule of heat application that maintains the overall temperature of the structure within the limit in which it retains its high strength. Therefore, it does not require internal tooling to support the structure against sagging which otherwise could occur when the bond line is heated above the high strength temperature limit. The process also produces nearly complete bond line area fusion on standard production composite material parts having the usual surface imperfections and deviations from perfect flatness. The multipass welding process eliminates fasteners and the expense of drilling holes, inspecting the holes and the fasteners, inspecting the fasteners after installation, sealing between the parts and around the fastener and the holes; reduces mismatch of materials; and eliminates arcing from the fasteners.
In the multipass process, an induction heating work coil is passed multiple times over a bond line while applying pressure in the region of the coil to the components to be welded, and maintaining the pressure until the resin hardens. The resin at the bond line is heated to the softening or melting temperature with each pass of the induction work coil. Pressure is exerted to flow the softened/melted resin in the bond line and to reduce the thickness of the bond line. The pressure improves the intimacy of the faying surface contact with each pass to improve continuity of the bond. The total time at the softened or melted condition of the thermoplastic in the faying surfaces is sufficient to attain deep interdiffusion of the polymer chains in the materials of the two faying surfaces throughout the entire length and area of the bond line. The process produces a bond line of improved strength and integrity in the completed part. The total time of the faying surfaces at the melting temperature is divided into separate time segments which allows time for the heat in the interface to dissipate without raising the temperature of the entire structure to the degree at which it loses its strength and begins to sag. The desired shape and size of the final assembly is maintained.
A structural susceptor allows us to include fiber reinforcement within the weld resin to alleviate residual tensile strain otherwise present in an unreinforced weld. The susceptor includes alternating layers of thin film thermoplastic resin sheets and fiber reinforcement (usually woven fiberglass fiber) sandwiching the conventional metal susceptor that is embedded in the resin. While the number of total plies in this structural susceptor is usually not critical, we prefer to use at least two plies of fiber reinforcement on each side of the susceptor. This structural susceptor is described in greater detail in U.S. Pat. No. 5,717,191, which I incorporate by reference.
The structural susceptor permits gap filling between the welded composite laminates which tailors the thickness (number of plies) in the structural susceptor to fill the gaps, thereby eliminating costly profilometry of the faying surfaces and the inherent associated problem of resin depletion at the faying surfaces caused by machining the surfaces to have complementary contours. Standard manufacturing tolerances produce gaps as large as 0.120 inch, which are too wide to create a quality weld using the conventional susceptors.
It is easy to tailor the thickness of the structural susceptor to match the measured gap by scoring through the appropriate number of plies of resin and fiber reinforcement and peeling them off. In doing so, a resin rich layer will be on both faying surfaces and this layer should insure better performance from the weld.
b. Fixed Coil Induction Welding
Thermoplastic welding using Boeing's induction heating workcell differs from the moving coil processes because of the coil design and resulting magnetic field. The fixed coil workcell promises welding at faster cycle times than the moving coil processes because it can heat multiple susceptors simultaneously. The fixed coil can reduce operations to minutes where the moving coil takes hours. The keys to the process, however, are achieving controllable temperatures at the bond line in a reliable and reproducible process that assure quality welds of high bond strength. The fixed coil induces currents to flow in the susceptor differently from the moving coils and covers a larger area. Nevertheless, proper processing parameters permit welding with a fixed coil induction heating workcell using a susceptor at the bond line.
Another advantage with the fixed coil process is that welding can occur using the same tooling and processing equipment that we use to consolidate the skin, thereby greatly reducing tooling costs. Finally, the fixed coil heats the entire bond line at one time to eliminate the need for shims that are currently used with the moving coil. We can control the temperature and protect against overheating by using "smart" susceptors as a retort or as the bond line susceptor material or both.
The need for a susceptor in the bond line poses many obstacles to the preparation of quality parts. The metal which is used because of its high susceptibility differs markedly in physical properties from the resin or fiber reinforcement so dealing with it becomes a significant issue. The reinforced susceptor of U.S. Pat. No. 5,728,309 (which I also incorporate by reference) overcomes problems with conventional susceptors by including the delicate metal foils (0.10-0.20 inch wide.times.0.005-0.010 inch thick; preferably 0.10-0.007 inch) in tandem with the warp fibers of the woven reinforcement fabric. The foil is always on the remote side of the fabric because it is between the warp thread and the weave threads. This arrangement holds the foils in place longitudinally in the fabric in electrical isolation from each other yet substantially covering the entire width of the weld surface while still having adequate space for the flow and fusion of the thermoplastic resin. Furthermore, in the bond line, the resin can contact, wet, and bond with the reinforcing fiber rather than being presented with the resinphilic metal of the conventional systems. There will be a resin-fiber interface with only short runs of a resin-metal interface. The short runs are the length of the diameter of two weave fibers plus the spatial gap between the weave fibers, which is quite small. Thus, the metal is shielded within the fabric and a better bond results. In this woven arrangement to foil can assume readily the contour of the reinforcement. Finally, the arrangement permits efficient heat transfer from the foil to the resin in the spatial region where the bond will focus.
I improve the strength and durability of adhesive bonds or thermoplastic welds connecting composite structure by adding Z-pin mechanical reinforcement to the bond line.
4. Z-Pin Reinforcement
First, some general discussion about the benefits of Z-pins in composite assemblies.
Composite sandwich structures having resin matrix skins or facesheets adhered to a honeycomb or foam core are used in aerospace, automotive, and marine applications for primary and secondary structure. The facesheets typically are reinforced organic matrix resin composites, made from fiberglass, carbon, ceramic, or graphite fibers reinforcing a thermosetting or thermoplastic matrix resin. The facesheets carry the applied loads, and the core transfers the load from one face sheet to the other or absorbs a portion of the applied load. In either case, it is important that all layers of the structure remain rigidly connected to one another. Noise suppression sandwich structure or sandwich structures for other applications are described in U.S. Pat. No. 5,445,861, which I also incorporate by reference.
Keeping the facesheets adhered to the foam is problematic. For simplicity, I refer to a foam core sandwich structure as an example. The most common source of delamination stems from a relatively weak adhesive bond that forms between the facesheets and the foam core. That is, pulloff strength of the facesheets in shear is low. Efforts to strengthen the bond have generally focused on improving the adhesive, but those efforts have had limited success.
Delamination can arise from differences in the coefficient of thermal expansion (CTE) of the different material layers. As a result, as temperatures oscillate, the facesheet or foam may expand or contract more quickly than its adjoining layer. In addition to causing layer separation, CTE differences can significantly distort the shape of a structure, making it difficult to maintain overall dimensional stability. Conventional sandwich structure optimizes the thickness of a structure to meet the weight and/or space limitations of its proposed application. Sandwich structures are desirable because they are usually lighter than solid metal or composite counterparts, but they may be undesirable if they must be larger or thicker to achieve the same structural performance. Providing pass-throughs (i.e., holes), which is relatively easy in a solid metal structure by simply cutting holes in the desired locations, is more difficult in a composite sandwich structure because holes may significantly reduce the load carrying capability of the overall structure.
Foster-Miller has been active in basic Z-pin research. U.S. Pat. No. 5,186,776 describes a technique for placing Z-pins in composite laminates involves heating and softening the laminates with ultrasonic energy with a pin insertion tool which penetrates the laminate, moving fibers in the laminate aside. The pins are inserted either when the insertion tool is withdrawn or through a barrel in the tool prior to its being withdrawn. Cooling yields a pin-reinforced composite. U.S. Pat. No. 4,808,461 describes a structure for localized reinforcement of composite structure including a body of thermally decomposable material that has substantially opposed surfaces, a plurality of Z-pin reinforcing elements captured in the body and arranged generally perpendicular to one body surface. A pressure plate (i.e., a caul plate) on the other opposed body surface drives the Z-pins into the composite structure at the same time the body is heated under pressure and decomposes. I incorporate U.S. Pat. Nos. 4,808,461 and 5,186,776 by reference.
A need exists for a method to form a sandwich structure that (1) resists distortion and separation between layers, in particular, separation of the facesheets from the core; (2) maintains high structural integrity; (3) resists crack propagation; and (4) easily accommodates the removal of portions of core, as required by specific applications. The method should allow the structure to be easily manufactured and formed into a variety of shapes. In U.S. patent application Ser. No. 08/582,297 (which I incorporate by reference), I described such a method of forming a pin-reinforced foam core sandwich structure. Facesheets of uncured fiber-reinforced resin (i.e., prepreg or B-stage thermoset) are placed on opposite sides of a foam core. The core has at least one compressible sublayer and contains a plurality of Z-pins spanning the foam between the facesheets. Z-pins are driven into the facesheets during autoclave curing of the face sheet resin when a compressible sublayer is crushed and the back pressure applied through the caul plate or other suitable means drives the Z-pins into one or both of the facesheets to form a pin-reinforced foam core sandwich structure. By removing some of the foam core by dissolving, eroding, melting, drilling, or the like to leave a gap between the facesheets, I produce my corresponding column core structure.
The foam core generally is itself a sandwich that includes a high density foam sublayer, and at least one low density, compressible or crushable foam sublayer. The preferred arrangement includes a first and second low density foam sublayer sandwiching the high density sublayer. The Z-pins are placed throughout the foam core in a regular array normal to the surface or slightly off-normal at an areal density of about 0.375 to 1.50% or higher, as appropriate, extending from the outer surface of the first low density foam sublayer through to the outer surface of the second low density foam sublayer. Expressed another way with respect to the arrangement of the pins, I typically use 200 pin/in.sup.2 or more. Preferably, the foam sublayers are polyimide or polystyrene, the Z-pins are stainless steel or graphite, and the facesheets are fiber-reinforced, partially cured or precured thermosetting or thermoplastic resin composites.
In U.S. Pat. No. 5,589,016 Hoopingarner et al., describe a honeycomb core composite sandwich panel having a surrounding border element (i.e., a "closeout") made of rigid foam board. The two planar faces of the rigid foam board are embossed or scored with a pattern of indentations usually in the form of interlinked equilateral triangles. The scoring is sufficiently deep and numerous to provide escape paths for volatiles generated inside the panel during curing and bonding of the resin in the facesheets to the honeycomb core and peripheral foam. The scoring prevents the development of excessive pressure between the facesheets in the honeycomb core that otherwise would interfere with the bonding. I incorporate this application by reference.
Rorabaugh and Falcone discovered two ways to increase the pulloff strength in foam core sandwich structure. First, they form resin fillets around the fiber/resin interfaces at the contact faces of the foam core by dimpling the foam to create a fillet pocket prior to resin flow during curing. Second, they arrange the pins in an ordered fashion such as a tetrahedral configuration or a hat section configuration. In tetrahedral or hat section configurations, the pins not only provide a tie between the two skins but they also provide miniature structural support suited better for load transfer than normal or random off-normal (interlaced) or less ordered pin configurations. With ordering of the pins, they produce anisotropic properties. More details concerning their Z-pin improvements are available in their U.S. Pat. No. 5,869,165 entitled "Highly Ordered Z-Pin Structures," which I incorporate by reference.
In U.S. Pat. No. 5,876,540 entitled "Joining Composites Using Z-pinned Precured Strips," Pannell describes bond line reinforcement achieved by using precured strips to carry the Z-pins. Pannell positions his strips between two detail parts and joins the three piece assembly with bonding, cocuring, or welding. I incorporate this Pannell application by reference.
I have discovered how to add Z-pins to thermoplastic welds or to adhesive bonds in induction heating bonding processes to improve the bond or weld pulloff strength.

Z-pin reinforced, bonded composite structure


This disclosure describes a Soil Penetrating Electrode with Conical Taper for use with instrumentation for measurement of the electrical properties of soil in situ. The Electrode shape and configuration solves problems of stable and reliable contact with the soil, repeatable contact area, and ease of use by the operator.

1. Field of the Invention
The invention relates to the field of soil mechanics where measurement of soil percent compaction and moisture content are required for road beds and construction foundations. More particularly, the invention relates to the measurement of soil electrical resistance and soil electrical capacitance at a radio frequency, wherein electrodes are used to connect the measurement instrumentation to the soil.
2. Prior Art
There have been many applications wherein soil electrical properties have been measured to determine geological characteristics of soils and earth structures in situ. Generally the electrode structure has not been identified in the description of these inventions. U.S. Pat. No. 5,450,012, issued to Champagne, et. al. on Sep. 12, 1995, describes a Soil Electrode design that is claimed to be useful for determination the resistance of a volume of soil. Other prior art includes U.S. Pat. No. 2,611,643 of R. V. Higgins, granted on Sep. 23, 1952 that describes an automatic sprinkling device which includes two electrodes inserted into soil. U.S. Pat. No. 3,905,551 of Charles Ayme de la Lachevreliere, granted on Sep. 17, 1975 describes a soil sprinkling device employing two electrodes, one lying in the upper sprinkled layer, and the other lying within the permanently moist layer at sufficient depth.

Soil penetrating electrode with conical taper


The present invention is directed to a device for facilitating the heating of a food product having an interior and an exterior, the device comprising an antenna for receiving microwave energy generated by a microwave source, such as a microwave oven, and converting the microwave energy into an electric current, and at least two probes in contact with the antenna and the interior of the food product for directing the current into the interior of the food product, whereby the interior of the food product is resistively heated.

The present invention is directed to a device for facilitating the heating of food products in a microwave oven. More particularly, the invention is directed to such a device which converts the microwave energy into electric current and directs the current across the core of the food product to heat the food product from the inside out.
Conventional conductive and convective methods of cooking or warming food products heat the food products from the outside in. This is also true of microwave cooking, wherein the microwave energy is attenuated from the outside to the inside of the food product. Consequently, certain food products are sometimes overcooked on the outside while the inside remains undercooked. In addition, it is difficult using these prior art heating methods to obtain a food product which is unheated on the outside but heated on the inside.

Microwave induced thermal inversion packaging