A vented door for a computer system includes a vented base and an outer door. The vented base and the outer door are separately pivotable. The vented base is pivotably attached to the computer system's enclosure for movement between a closed configuration where the vented base abuts against a panel of the enclosure and an open configuration where the vented base is swung away from the panel. The outer door is pivotably attached to the vented base to avoid interfering with a neighboring computer system's vented door as the vented base is pivoted to the open configuration. An acoustic noise reduction lining is provided on the outer door and in the air flow apertures of the vented base. The outer door is preferably removable from the vented base so that the combined weight of the vented base and the outer door need not be lifted when removal is necessary.

1. Field of Invention
The present invention relates in general to housings for enclosing computer systems and in particular to vented doors with acoustic attenuation for use with such housings. More particularly, the present invention relates to a computer system which includes a vented door having a pivotable vented base and an outer door that is pivotable relative to the base.
2. Background Art
Computer systems are using larger amounts of energy, and are generating more heat. Increased heat generation is driven by factors such as increases in processor performance and clock speed, and increases in the number of devices per integrated circuit. Electronic components, such as microprocessors and integrated circuits, must operate within certain specific temperature ranges to perform efficiently. Excessive heat degrades electronic component performance, reliability, life expectancy, and can even cause failure. Air moving devices (AMDs), such as fans and blowers, are widely used for controlling excessive heat. AMDs are often used in combination with heat sinks thermally connected to electronic components to be cooled. Typically, heat sinks are formed with fins to increase the surface area of the heat sink and thereby enhance heat dissipation as air moved by an AMD passes over the heat sink.
In many large server applications, the processors of a computer system along with their associated electronics (e.g., memory, disk drives, power supplies, etc.) are packaged in removable drawer configurations stacked within a rack or frame. In other cases, the processors of a computer system along with their associated electronics may be in fixed locations within the rack or frame. Typically, the components are cooled by air moving in parallel air flow paths, usually front-to-back, impelled by one or more AMDs.
With the advent of the increased heat generated by computer systems, increased ventilation is required to move cooling air through the computer system. A failure to provide adequate ventilation through a computer system may increase the probability of computer failure due to overheating and may result in damage to the electronic components. Due to the great expense of these electronic components and the concomitant loss of processing time associated with such failures, it is desirable that adequate ventilation be maintained for computer systems. Increased air flow rates are needed to provide adequate ventilation. However, the acoustic noise associated with the increased air flow rates required to provide adequate ventilation, as well as acoustic noise generated by the various components within the computer system, represents a problem that must be overcome. There are limits on the acoustic output of computer systems (e.g., servers and storage products) set by vendors, governments, standards setting bodies, and the like.
In order to reduce acoustic noise, it is known to utilize an acoustic noise reduction lining in vented covers of computer systems. An example of such an arrangement is found in U.S. Pat. No. 5,526,228, issued Jun. 11, 1996 to Dickson et al., entitled "COMPUTER SYSTEM UNIT WITH ACOUSTIC DAMPENING COOLING FAN SHROUD PANEL", which is assigned to the assignee of the present application. As shown in FIG. 1, a cooling fan shroud panel 16 includes an acoustic noise reduction lining comprising a side acoustic foam panel 28 and a top acoustic foam panel 30. The acoustic dampening cooling fan shroud panel 16 is mounted to an intermediate rear panel 32 of a computer system unit 10. Two cooling fans 34, 36 are mounted within fan mounting apertures 35, 37 of the intermediate rear panel 32. The cooling fans 34, 36 draw air through computer system unit 10 from an intake ventilation grill (not shown) of a front panel 12 in the direction indicated by the arrows designated with reference numeral 44. Mounted within computer system unit 10 are a power supply 38 and an electronic component package 40, which are cooled by the air drawn through computer system unit 10. Air is directed out an exiting ventilation aperture 22 of cooling fan shroud panel 16 in the direction indicated by the arrow designated with reference numeral 42. The exiting ventilation aperture 22 is displaced from the mounting position of the cooling fans 34, 36 such that acoustic noise resultant from the cooling fan operation is diminished. Even though acoustic dampening cooling fan shroud panel 16 is effective in diminishing acoustic noise, it exhibits a number of disadvantages. First, the relatively substantial depth of acoustic dampening cooling fan shroud panel 16 significantly increases the footprint of computer system unit 10. Second, the small area of exiting ventilation aperture 22 relative to intermediate rear panel 32 reduces the cooling efficiency.
FIG. 2 shows another example of the utilization of acoustic noise reduction lining in vented covers found in the IBM eServer zSeries 900 server. As shown in FIG. 2 (Top View), an inlet cover 210 includes an acoustic noise reduction lining comprising two outer acoustic foam panels 212 and central acoustic foam block 214. Inlet ventilation apertures 216 are defined between outer acoustic foam panels 212 and central acoustic foam block 214. Inlet cover 210 also includes intake extensions 213 and 215 that respectively project from one of the two outer acoustic foam panels 212 and central acoustic foam block 214. In addition, inlet cover 210 includes four curved vanes 217. Intake extensions 213, 215 and curved vanes 217 are configured and positioned to suitably direct and distribute the incoming air through inlet ventilation apertures 216 and toward the various heat generating components housed within a computer system frame or rack 200. Similarly, an exhaust cover 220 includes an acoustic noise reduction lining comprising two outer acoustic foam panels 222 and central acoustic foam block 224. Exhaust ventilation apertures 226 are defined between outer acoustic foam panels 222 and central acoustic foam block 224.
The inlet cover 210 and the exhaust cover 220 are mounted to computer system frame or rack 200 using hinges (not shown) so that removable drawers (not shown) stacked within computer system frame 200 may be accessed when inlet cover 210 and/or exhaust cover 220 is/are swung open via the hinges. AMDs (not shown) draw air through computer system frame 200 from inlet ventilation apertures 216 and exhaust the air through exhaust ventilation apertures 226. The air moves in the direction indicated by arrows designated by reference numeral 230. The removable drawers, which contain processors and their associated electronics, are cooled by the air drawn through computer system frame 200, as are electronic components fixed within computer system frame 200. Acoustic noise resultant from the AMD operation is effectively diminished by inlet cover 210 and exhaust cover 220 which have three main attributes: a large amount of acoustic absorbing material; an air/noise path that curves or angles to force sound to impact the acoustic lining; and minimum sharp bends in the air path to minimize airflow resistance.
Even though inlet cover 210 and exhaust cover 220 are effective in diminishing acoustic noise, they exhibit a number of disadvantages. First, the relatively substantial depth of inlet cover 210 and exhaust cover 220 significantly increase the footprint of computer system frame 200. For example, to accommodate a sufficient amount of acoustic foam and air inlet openings of sufficient size, the depth of inlet cover 210 (denoted as dimension "D" in FIG. 2) often exceeds 12 inches.
Second, the weight of inlet cover 210 and exhaust cover 220 can be excessive. For example, the weight of inlet cover 210 often approaches or exceeds the maximum weight one person is permitted to lift (e.g., 39.7 pounds). This situation is disadvantageous because it requires two customer engineers (CEs) to be sent on service calls.
Third, inlet cover 210 and exhaust cover 220 are dimensionally confined to an area within a physical envelope necessary to allow adjacent covers to hinge open against each other. The inlet cover 210 and exhaust cover 220 are typically chamfered 45° on each side as shown in FIG. 2 to allow adjacent cover doors to hinge open 90° against each other. Accordingly, the dimensions of inlet cover 210 and exhaust cover 220 are each limited to an area within a physical envelope (denoted in FIG. 2 as two dashed lines labeled as 240 with respect to inlet cover 210) that does not interfere with swinging one cover open 90° against an adjacent cover.
FIG. 3 shows an inlet cover 210 swung open 90° via one or more hinges (not shown) against an adjacent inlet cover 210, which is closed against its computer system frame 200. As mentioned above, each inlet cover may be swung open 90° to access components within its computer system frame, such a removable drawers.
It should therefore be apparent that a need exists for a computer system enclosure which can both adequately ventilate a computer system housed therein and reduce the amount of acoustic noise, while addressing the disadvantages of the prior art.

Method and apparatus for acoustic noise reduction in a computer system having a vented door including a pivotable vented base and a pivotable outer door

International Business Machines Corporation


Aspects of the present disclosure relate to machine learning techniques for continuous implementation and training of a machine learning system for identifying the natural language meaning of visual content. A computer vision model or other suitable machine learning model can predict whether a given descriptor is associated with the visual content. A set of such models can be used to determine whether particular ones of a set of descriptors are associated with the visual content, with the determined descriptors representing a meaning of the visual content. This meaning can be refined based on a multi-armed bandit tracking and analyzing interactions between the visual content and users associated with certain personas related to the determined descriptors.

Artificial intelligence describes computerized systems that can perform tasks typically considered to require human intelligence. The capability to learn is an important aspect of intelligence, as a system without this capability generally cannot become more intelligent from experience. Machine learning is a field of computer science that gives computers the ability to learn without being explicitly programmed, for example enabling artificial intelligence systems to learn complex tasks or adapt to changing environments.

Continuous machine learning for extracting description of visual content


Provided is a connector which can facilitate tuning of frequency of pulsation to be reduced and prevent sealing performance from degrading when a piston moves. A pulsation reducing member adopts a structure in which the piston moves in a cylinder. The cylinder has an annular flange portion projecting in a radially inner direction of a hollow cylindrical shape. An elastic sealing member is sandwiched in a compressed state between an end surface of the flange portion of the cylinder and an end surface of the piston. An urging body is disposed in a region in the cylinder on a side of the piston opposite to a passage and applies urging force to move the piston toward the passage and compress the elastic sealing member.

1. Field of the Invention
The present invention relates to a connector in a piping system and more particularly to a connector capable of reducing pulsation of fluid in conveying the fluid.
2. Description of the Related Art
For example, in a piping system for a fuel supply system of an automobile, a connector connects a hose for conveying pressurized fuel from a pump, and a fuel delivery pipe for delivering and distributing the fuel to a plurality of injectors. In such a piping system, fuel transfer is achieved by applying pressure to fuel in the hose by a pump so as to keep the pressure at a predetermined constant value. If injection apparatus such as injectors is opened or closed for fuel supply control while the piping system is placed under such a condition, pressure in the piping system changes and the fuel pulsates, as is well known. If the fuel pulsates, fuel pressure in the injection apparatus may become too high or too low and the amount of fuel to be injected by the injection apparatus may deviate from a desired amount.
Under these circumstances, a variety of techniques have been proposed to reduce pulsation. For example, in a connector mentioned in JP-A-2011-163154 (PTL 1), a cylinder is integrally formed with a housing of the connector and an O ring is provided on an outer circumferential portion of a piston so as to be in slidable contact with an inner circumferential surface of the cylinder. The piston and the O ring liquid-tightly divide a fuel chamber which communicates with a fuel passage and an air chamber which holds the air. When pressure variation is small at an initial stage of pulsation, this connector reduces the pressure variation by sliding resistance between the O ring and the inner circumferential surface of the cylinder. When a pressure variation which cannot be reduced by the sliding resistance occurs, the pressure variation is reduced by the air in the air chamber.


An apparatus and method is disclosed for providing recovery and backoff rules for a hybrid coordinator of an IEEE 802.11e Quality of Service (QoS) wireless station. The invention comprises a wireless local area network that is capable of using the recovery and backoff rules of the present invention in the Medium Access Control (MAC) layer of QoS hybrid coordinators. The HC recovery and backoff rules of the present invention minimize collisions especially when hybrid coordinators from an overlapping basic service set are present.

The development of high quality multimedia devices, such as set-top boxes, high end televisions, digital televisions, personal televisions, storage products, personal digital assistants (PDAs), wireless Internet devices, etc., is leading to a variety of architectures and to more openness towards new features for these devices. The development of these new multimedia products ensures that the public will continue to increase its demand for multimedia services. Network designers and engineers are therefore continuing to design systems that are capable of meeting the increasing demand for both real time and non-real time multimedia transfer across integrated networks.
The Internet Protocol (IP)-based Internet provides a "best effort" data delivery service that does not guarantee any service level to the users. A "best effort" service over the IP network allows the complexity to stay at the end-hosts, so that the network can remain simple. The phenomenal growth of the Internet shows that this approach scales well.
On the other hand, in recent years, the IEEE 802.11 wireless local area network (WLAN) has emerged as a prevailing technology for the (indoor) broadband wireless access for mobile/portable devices. IEEE 802.11 can be considered a wireless version of "Ethernet" by virtue of supporting a "best effort" service. The IEEE 802.11 Working Group is currently defining a new supplement to the existing legacy 802.11 Medium Access Control (MAC) layer in order to support Quality of Service (QoS). The new 802.11e MAC will expand the 802.11 application domain by enabling such applications as voice and video services over wireless local area networks (WLANs).
The new IEEE 802.11e standard will constitute the industry's first true universal wireless standard supporting QoS. IEEE 802.11e will offer seamless interoperability across home, enterprise, and public access networking environments, yet still offer features that meet the unique needs of each type of network. Unlike other wireless initiatives, IEEE 802.11e is the first wireless standard that spans home and business environments by adding QoS features and multimedia support to the existing IEEE 802.11 standard, while maintaining full backward compatibility with the legacy standard.
The QoS support for multimedia traffic is critical to wireless home networks where voice, audio, and video will be delivered across multiple networked home electronic devices and personal computers. Broadband service providers view QoS and multimedia-capable home networks as an essential ingredient to offering residential customers value-added services such as video on demand, audio on demand, voice over IP and high speed Internet access.
In order to provide adequate service, some level of quantitative and qualitative determinations of the types of network services will be required. This requires adding some capability to the network to enable the network to distinguish traffic with strict timing requirements on delay, jitter and loss from other types of traffic. This is what the protocols for QoS provisioning are designed to achieve. QoS provisioning does not create bandwidth, but manages bandwidth more effectively to meet a wide range of application requirements. The goal of QoS provisioning is to provide some level of predictability and control beyond the current IP "best effort" service.
The currently proposed IEEE 802.11e specification provides recovery and backoff rules for a hybrid coordinator (HC) of a Quality of Service (QoS) wireless network. However, the rules as currently proposed are inconsistent in that they do not provide an appropriate response in every case that might occur during the operation of the HC.
HC backoff is not needed in those cases in which the HC has full control of the wireless medium. However, HC backoff is desirable in those cases in which an Overlapping Basic Service Set (OBSS) is present. But performing an HC backoff may result in a collision between QoS wireless stations (QSTAs) in the Quality of Service (QoS) Basic Service Set (QBSS) and the HC.
There is therefore a need in the art for an apparatus and method that will provide a more comprehensive and consistent set of recovery and backoff rules for the Medium Access Control (MAC) layer of an IEEE 802.11e Quality of Service (QoS) hybrid coordinator.

Apparatus and method for providing IEEE 802.11e hybrid coordinator recovery and backoff rules


A small plastic animal container assembly or kit of parts for bathing small pets in a home bathtub or shower stall. The container assembly includes foldable legs to raise it to a height that allows a person to stand while administering the bath. The container walls are bowed outward in the middle providing more room for a small animal to easily turn around, yet provide confinement for an animal of predetermined size. The bottom of the container has a centralized drain and pet hair filter channel which runs lengthwise along the entire bottom of the container and includes a sufficient number of strategically placed drain holes to provide for continuous water removal and filtering of loose pet hair. Pockets are integrally molded into the four corners of the container to provide a means to hold pet bathing accessories such as shampoo, a brush, a sponge, etc. A clip is built into or attached to one end of the container to provide a means to hold a variety of sizes of handles used on shower water spray heads. The spray heads are connected to a flexible hose and are part of the bathtub or shower stall fixtures found in many existing bathrooms. The clip provides a place to hold the handle of the spray head in a downward facing position so that the water is directed toward the bottom of the bathtub or shower stall, thus negating the need to turn the water on and off each time you need to apply water to the pet. Texture on the bottom surface of the container provides a non-skid surface for the pet to stand. Slots are formed in the rim of the container to which a retaining strap can be attached to the collar of the animal. The support legs have non-skid feet or shoes to prevent damage and slippage on the bottom surface of the bathtub or shower stall. The legs of the container can be un-snapped from the bottom of the container and folded flat for storage.

Currently, pet owners have few options available outside of special commercial grooming facilities or elaborate devices for bathing their pets at home. Small common household pets, such as small dogs, are typically washed in the family bathtub, shower stall, laundry sink, kitchen sink or infrequently in a general purpose style washtub which is usually placed on a patio, driveway or lawn. Such bathing methods, while capable of assisting in the bathing of pets, suffer however from many drawbacks. For example, except for some general purpose wash tubs which are typically used outdoors, almost all of the above known available bathing options share a common problem of exposed drains which are susceptible of being clogged by pet hair that is shed during the bathing procedure.
While the kitchen sink provides an area for bathing small pets, most sinks are not designed or equipped to allow a user to easily bathe a small pet. Besides miniature breeds, many small dogs are simply too large to fit into a common kitchen sink. Moreover, one who is experienced in bathing dogs understands that most become frightened when bathed and frequently try to escape. Therefore, controlling a frightened dog during a bath can require substantial energy and patience. If the dog struggles and escapes, it may injure itself leaping from the kitchen sink to the floor. Furthermore, dogs typically try to shake the water and shampoo from their coats throughout the bathing process which can land on the surrounding counter top adjacent the sink, on the floor which may create a potentially slippery area, on the walls which may have expensive wall coverings, and on the person administering the bath. Besides creating a mess which must be cleaned up, the above typical occurrences may damage costly personal property such as wall coverings or pet hair accumulating in and damaging the disposal.
Most importantly, many people find the idea of bathing a small dog in the kitchen sink offensive and potentially hazardous to ones health because the sink is also used in the preparation of food. Since many dog shampoos include potentially toxic medications for one reason or another, any lingering shampoo or residue in the sink or on the adjacent counter top may be absorbed into food which may be harmful if consumed. Also, because the kitchen sink is one of the primary areas where food is prepared, a person who has bathed their pet in the sink will typically spend more time and energy sanitizing and deodorizing the sink and adjacent area than if the pet were bathed in another area.
A general purpose washtub is not especially adapted to wash a small animal therefore, if used, is inconvenient and time consuming. Moreover, as stated above, the pet must be washed outdoors typically using a garden hose or rinse bucket to rinse the animal. Using a rinse bucket does not normally allow thorough rinsing of the underside of the pet. Since the washtub is usually limited to outdoor use, this option typically prohibits bathing the animal in bad or cold weather. Also, in order to be a somewhat user friendly, the washtub can be placed upon a table or the like. However, if elevated, the washtub will be very difficult to empty once the bathing is completed because most typically do not include drains.
Even though a laundry sink offers a convenient place for bathing small dogs, it suffers from generally the same drawbacks as the kitchen sink. In addition, however, most homes and apartments do not have a laundry sink available, and those that do, most are not equipped with a spray device. Therefore, the person bathing the pet will have to use a rinse bucket to rinse the pet which can be very messy depending on the nature of the pet.
The family bathtub or shower stall both provide an area for washing and rinsing a small animal, however, they too present several disadvantages. One problem associated with using the bathtub or shower stall is that most small dogs will not remain in one place when put into the large area provided by the bathtub or stall. Since the dog must remain standing on the bottom of the tub or stall, the person administering the bath must stoop down on his or her knees and bend uncomfortably over to bathe and control the dog. Such strenuous activity is simply impossible for many people, especially those who suffer from chronic knee or back problems. Moreover, although many home bathtubs or shower stalls are now equipped with removable hand held shower heads that are attached to a flexible hose, the standard length of a flexible hose is typically not long enough to allow the hand held shower head to adequately reach a small dog standing on the bathtub or shower stall floor. In addition, there is not a convenient place to hold or secure the hand held shower head while bathing the pet, therefore it usually cannot, without creating a mess, be left running. Thus, between each rinse, the water typically is turned off, creating a need to readjust the water temperature each time the water is turned back on. Lastly, dog hair will usually accumulate in the tub drain causing potentially expensive plumbing problems.
All of the above described "home" methods for bathing a small pet have some type of undesirable disadvantage. These problems are basically due to the fact that none of the listed "home" bathing areas are designed specifically for small dogs. In an attempt to remedy some of the disadvantages associated with the above described "home" bathing techniques or areas, several pet bathing devices have been designed. While these devices are functional for their intended purpose, they too include many drawbacks not suitable for the average in home user.
One problem associated with known pet bathing devices is that most have multiple part complex constructions which translates into increased cost to the consuming public and increased time necessary to adequately clean the device. A typical pet bathing device includes an elaborate drain screen or filter which is either located over or in an actual drain hole. Besides being difficult to remove, these separate "filtering" devices are difficult to clean after use. Typically, most screens or filters must be removed from the pet bathing apparatus and transported to another location, typically outdoors, to be cleaned and rinsed with a garden hose in order to be thoroughly cleaned. Removing the screen or filter just to clean it in the bathtub or sink would defeat the intended purpose of having the screen or filter in the first place.
Some of the known pet bathing devices also include separate covers, narrow side walls and elaborate neck restraining devices in order to severely limit, if not totally prevent, the animals movement during bathing. Utilizing such features or devices may not only traumatize the animal but also may not be appealing to the consuming public because many dog owners would probably not subject their dogs to such restraint. Moreover, even if such pet bathing devices are specifically designed for commercial use in a professional grooming facility where many dogs are bathed on a regular day-to-day basis, such facilities do not have the same burden or personal responsibility of protecting individual personal property from damage as describe above in the case of home pet bathing.
In view of the foregoing disadvantages inherent in "home" bathing techniques and areas and disadvantages associated with known pet bathing devices, a need exists for a light weight low cost simply constructed small animal washing container assembly designed specifically for small dogs that is both user friendly and pet friendly. A further need in the pet bathing industry exists for a small animal washing container assembly specifically designed for in home use of existing bathroom fixtures. An even further need exists in the industry for a small animal washing container that is specifically designed to be easily cleaned and stored in a minimum amount of time and energy.


Disclosed are apparatus and methods for facilitating caching in a storage area network (SAN). In general, data transfer traffic between one or more hosts and one or more memory portions in one or more storage device(s) is redirected to one or more cache modules. One or more network devices (e.g., switches) of the SAN can be configured to redirect data transfer for a particular memory portion of one or more storage device(s) to a particular cache module. As needed, data transfer traffic for any number of memory portions and storage devices can be identified for or removed from being redirected to a particular cache module. Also, any number of cache modules can be utilized for receiving redirected traffic so that such redirected traffic is divided among such cache modules in any suitable proportion for enhanced flexibility.

The present invention relates to storage area networks. More particularly, the present invention relates to methods and apparatus for providing cache storage in a storage area network (SAN).
A particular SAN has different cost and performance aspects based on the type of storage systems deployed. The high end storage systems like EMC Symmetrix, DMX, Hitachi 9960s, IBM Shark, etc. have customized hardware designed for scalability of memory size (e.g., can provide hundreds of GB) and performance. However, these systems are extremely expensive.
In contrast, mid-range storage systems have limited amount of cache memory (e.g., a few GBs) and can not offer the performance levels of high end systems. There is also a utilization related problem in a SAN formed from a high number of mid-range storage systems. Unfortunately, the caches in both of the mid-range and high end systems are not sharable beyond the systems in which they reside. Assuming that at any given point in time, the hosts only access a particular amount of the storage (compared to the entire available capacity), it can be assumed that not all mid-range systems are going through storage access operations all the time. Accordingly, if the sum of caches of all those idling systems is a significant number, a significant amount of cache memory is unutilized.
In light of the foregoing, it would be beneficial to bridge the price and utilization gaps in current SAN cache memory systems.

Dynamic, on-demand storage area network (SAN) cache


A composition includes at least one organic compound of a first type of the general formula I and at least one organic compound of a second type of the general structural formula II, wherein Core in formula I is a conjugated organic unit capable of forming a rigid rod-like macromolecule, Gk is a set of ionogenic side-groups providing solubility of the organic compound of the first type in a solvent and give rigidity to the rod-like macromolecule; and wherein Sys in formula II is an at least partially conjugated substantially planar polycyclic molecular system capable of forming board-like supramolecules via π-π-interaction, and X, Y, Z and Q are substituents. The composition is capable of forming a lyotropic liquid crystal solution, which can form a solid retardation layer of biaxial type substantially transparent to electromagnetic radiation in the visible spectral range. The type and degree of biaxiality of the said optical retardation layer is controlled by a molar ratio of the organic compounds of the first and the second type in the composition. An optical film comprising a solid retardation layer formed of the composition, a method of producing the optical film, and a vertical alignment liquid crystal display using said retardation layer are also provided.

The liquid crystal display (LCD) technology has made considerable progress in the past years. There are a lot of TV sets, monitors and even public displays based on LCD panels on the market. The market of LCD is expected to keep growing in the near future.
The rapidly growing and changing market sets new tasks for researchers and manufacturers. Growing size of LCD diagonal, which has already exceeded 100 inch size, imposes stronger restrictions onto the quality of optical components. In case of retardation films, very small color shift and ability to provide higher contrast ratio at wide viewing angles are required for high-quality viewing of large displays.
Nowadays there are still some disadvantages of LCD technology which impact the quality of liquid crystal displays and still make feasible the competitive technologies like plasma display panel (PDP) in large-size and cathode-ray tube (CRT) in mid-size displays. One of disadvantages is a decrease of contrast ratio at oblique viewing angles. In conventional LCD the viewing angle performance is strongly dependent upon polarizers' performance. Typical LCD comprises two dichroic polarizers crossed at 90°. However, at oblique angles the angle between projections of their axes deviates from 90°, and polarizers become uncrossed. The light leakage increases with increasing off-axis oblique angle. This results in low contrast ratio at wide viewing angle along the bisector of crossed polarizers. Moreover, generally the light leakage becomes worse because of the liquid crystal cell placed between crossed polarizers.
Off-axis contrast drop issue in LCD can be successfully solved using phase retardation films, which represent optically anisotropic materials. In particular, biaxial retardation films which have three different principal refractive indices can be used for optical compensation of LCD. In contrast with uniaxial retardation films, the biaxial retardation films generally allow providing the best compensation effect using minimal number of compensating sheets.
Phase retardation optical films used for improvement of the LCD contrast at wide viewing angles are known in the art. Most of the conventional phase retardation films are produced by stretching of polymers such as polycarbonate, polyester, polynorbornene etc. Depending on the type of the stress employed on the polymeric film, it is possible to obtain uniaxial or biaxial retardation films of various types. However, the improvement of its performance is difficult due to limitations of the stretching manufacturing process.
Besides the stretching of the amorphous polymeric films, other polymer alignment techniques are known in the art. Thermotropic liquid crystalline polymers (LCP) can provide highly anisotropic films characterized by various types of birefringence. The production of such films comprises coating a polymer melt or solution on a substrate; for the latter case the coating is followed by the solvent evaporation. The additional alignment actions are involved, such as an application of the electric field, using of the alignment layer or coating onto a stretched substrate. The after-treatment of the coating is at a temperature at which the polymer exhibits liquid crystalline phase and for a time sufficient for the polymer molecules to be oriented. Examples of uniaxial and biaxial optical films production can be found in U.S. Pat. No. 5,132,147, and other patent documents and scientific publications.
Optical films can be also produced by coating of lyotropic liquid crystalline (LLC) solutions based on low-molecular compounds capable of forming columnar supramolecules as also known as chromonics. Extensive investigations aimed at developing new methods of fabricating chromonic-based films through variation of the film deposition conditions have been described in U.S. Pat. No. 5,739,296 and other patent documents and scientific publications. Of particular interest is the development of new compositions of lyotropic liquid crystals utilizing modifying, stabilizing, surfactant and/or other additives in the known compositions, which improve the characteristics of the films. The recent research has been directed to the materials used in the manufacturing of anisotropic films, polarizers and retarders for LCD and telecommunications applications, such as (but not limited to) those described in P. Yeh, Optical Waves in Layered Media, New York, John Wiley & Sons (1998), and P. Yeh, and C. Gu, Optics of Liquid Crystal Displays, New York, John Wiley & Sons, (1999).
It has been shown that ultra-thin optically anisotropic birefringent films based on organic dye LLC systems can be produced using the known methods and technologies. In particular, manufacturing of thin crystalline optically anisotropic films based on disulfoacids of dibenzimidazoles of naphthalenetetracarboxylic acid has been described by P. Lazarev and M. Paukshto (in: Proceedings of 7th IDW, (2000), pp. 1159-1160). In the above referenced films the molecules are packed with their minimal polarizability axis parallel to the film coating direction. This structure allows to produce uniaxial −A-plate or biaxial BA-plate retardation film types.
Water soluble rigid-rod polymers are also known to exhibit self-assembled structures in aqueous solutions. Such polymers are used as model objects which are able to reveal some mechanisms taking place in living organisms and implying natural rigid-rod polymers such as deoxyribonucleic acid (DNA), proteins, polysaccharides, having great abilities to form well-ordered structures by spontaneous self-assembly, which is fundamental to invoke their biological functions. As natural rigid-rod polyelectrolytes are difficult to extract without denaturation, synthetic analogues can be studied to investigate some aspects of polyelectrolites aggregation in aqueous solutions. For example, self-assembling properties of water-soluble poly(2,2′-disulfonylbenzidine terephtalamide (PBDT) were investigated by W. Yang et al. (Macromolecules, 41 (5), 1791-1799, 2008). The authors investigated the PBDT sodium salt in different concentration regions. It was shown that at concentration exceeding 3 wt. % the PBDT molecules can form liquid crystalline state. The investigation of electrolyte effect has also shown that adding of the salt (NaCl) enhances the association processes in the PBDT solutions.
Shear-induced mesophase organization of synthetic polyelectrolytes in aqueous solution was described by T. Funaki et al. in Langmuir, 2004, val. 20, 6518-6520. Poly(2,2′-disulfonylbenzidine terephtalamide (PBDT) was prepared by an interfacial polycondensation reaction according to the procedure known in the prior art. Using polarizing microscopy, the authors observed lyotropic nematic phase in aqueous solutions in the concentration range of 2.8-5.0 wt %. Wide angle X-ray diffraction study indicated that in the nematic state the PBDT molecules show an inter-chain spacing, d, of 0.30-0.34 nm, which is constant regardless of the concentration (2.8-5.0 wt %). The d value is smaller than that of the ordinary nematic polymers (0.41-0.45 nm), suggesting that PBDT rods in the nematic state have a strong inter-chain interaction in the nematic state to form the bundle-like structure despite the electrostatic repulsion of sulfonate anions. In the concentration range from 2 to 2.8 wt % a shear-induced birefringent (SIB) mesophase was observed.
A number of rigid rod water-soluble polymers were described by N. Sarkar and D. Kershner in Journal of Applied Polymer Science, Vol. 62, pp. 393-408 (1996). The authors suggest these polymers for different applications such as enhanced oil recovery. For these applications, it is essential to have a water soluble shear stable polymer that can possess high viscosity at very low concentration. It is known that rigid rod polymers can be of high viscosity at low molecular weight compared with the traditionally used flexible chain polymers such a hydrolyzed poly-acrylamides. New sulfonated water soluble aromatic polyamides, polyureas, and polyimides were prepared via interfacial or solution polymerization of sulfonated aromatic diamines with aromatic dianhydrides, diacid chlorides, or phosgene. Some of these polymers had sufficiently high molecular weight (<200,000 according to GPC data), extremely high intrinsic viscosity (˜65 dL/g), and appeared to transform into a helical coil in salt solution. These polymers have been evaluated in applications such as thickening of aqueous solutions, flocculation and dispersion stabilization of particulate materials, and membrane separation utilizing cast films.
Synthesis and properties of solutions of water-soluble polyamides are described by E. J. Vandenberg, W. R. Diveley, et al. in Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 27, pp. 3745-3757 (1989). Poly[N,N′-(sulfo-phenylene)phthalamidles and poly[N,N′-(sulfo-p-phenylene)pyromellitimidel were prepared in water-soluble form and it was found that their solution demonstrate unique properties, in some respects similar to xanthan. The most investigated polymer, poly[N,N′-(sulfo-p-phenylene)terephthalamide] (PPT-S), was produced as the dimethylacetamide (DMAC) salt by the solution polymerization of 2,5-diaminobenzenesulfonic acid with terephthaloyl chloride in DMAC containing LiCl. The isolated polymer requires heating to be dissolved in water; the resulting solutions are viscous solutions or gels at concentrations as low as 0.4%. They are highly birefringent, exhibit circular dichroism properties, and are viscosity-sensitive to the content of salt. Solutions of this polymer mixed with those of guar or hydroxyethyl cellulose give significantly enhanced viscosity. The polymer has a relatively low molecular weight, ca. 5000, as estimated from the viscosity data. Some meta- and para-isomeric analogs of PPT-S were prepared; these polymers have similar properties except they are more soluble in water, and higher concentrations are required to obtain significant viscosity. Poly[N,N′-(sulfo-p-phenylene) pyromellitimide] (PIM-S) was prepared similarly from 2,5-diaminobenzenesulfonic acid and pyromellitic dianhydride. Properties of its aqueous solutions are similar to those of PPT-S. It appears that these relatively low-molecular-weight rigid-chain polymers associate in water to form a network that results in viscous solutions at low concentrations.
Self-assembling properties of sulfonated poly-paraphenylene terephthalamides were considered as a function of number and relative position of sulfonic groups to the main chain by E. Mendes, S. Viale, and S. J. Picken in Proc. Symp. on Functional Polymer Materials, 2004. The authors report, that when the repeated unite contains only one sulfonic group, the structure of the aqueous solutions vary from gel in case of poly(sulfo-paraphenylene terephtalamide) to supramolecular nematic liquid crystal in the case of poly(paraphenylene sulfoterephthalamide). Thus the position of the sulfonic group dramatically affects the structure of the solutions. When two sulfonic groups are present in the repeating unit (in case of poly(sulfo-paraphenylene sulfoterephthalamide)), a molecular polyelectrolyte lyotropic liquid crystal is formed.
The present invention provides solutions to the above referenced disadvantages of the optical films for liquid crystal display or other applications, and discloses a new type of optical film, in particular a biaxial retardation layer.

This patent is subject to a terminal disclaimer.

Composition of organic compounds, optical film and method of production thereof


A method of producing a polylactic acid block copolymer constituted of a segment(s) composed of L-lactic acid units and a segment(s) composed of D-lactic acid units, includes obtaining a mixture by mixing poly-L-lactic acid and poly-D-lactic acid one of which has a weight average molecular weight of 60,000 to 300,000 and the other of which has a weight average molecular weight of 10,000 to 50,000, the mixture having a weight average molecular weight of not less than 90,000 and a degree of stereocomplexation (Sc) satisfying: Sc=ΔHh/(ΔHl+ΔHh)×100>60 (wherein ΔHh represents the heat of fusion of stereocomplex crystals (J/g), and ΔHl represents the heat of fusion of crystals of poly-L-lactic acid alone and crystals of poly-D-lactic acid alone (J/g)); and subsequently subjecting the mixture to solid-phase polymerization at a temperature lower than the melting point of the mixture.

Polylactic acid is a macromolecule which can be practically subjected to melt molding and, because of its biodegradable property, it has been developed as biodegradable plastics that are degraded after use under a natural environment to be released as carbon dioxide gas and water. In addition, since the raw material of polylactic acid itself is a renewable resource (biomass) originated from carbon dioxide and water, release of carbon dioxide after its use neither increases nor decreases carbon dioxide in the global environment. Such a carbon-neutral nature of polylactic acid is drawing attention in recent years, and it is expected to be used as an eco-friendly material. Further, lactic acid, which is the monomer for polylactic acid, can be inexpensively produced by fermentation methods using microorganisms in recent years, and polylactic acid is therefore being studied as a material alternative to general-purpose polymers made of petroleum-based plastics. However, in comparison with petroleum-based plastics, polylactic acid has lower heat resistance and durability, and also has lower productivity due to its lower crystallization rate. Therefore, its practical use is largely restricted at present.
As a means to solve such problems, use of a polylactic acid stereocomplex is drawing attention. A polylactic acid stereocomplex is formed by mixing optically active poly-L-lactic acid (hereinafter referred to as PLLA) and poly-D-lactic acid (hereinafter referred to as PDLA), and its melting point reaches 220° C., which is 50° C. higher than the melting point of a polylactic acid homopolymer, 170° C. Therefore, attempts are being made to apply polylactic acid stereocomplexes to production of fibers, films and resin molded articles having high melting points and high crystallinities.
Conventionally, a polylactic acid stereocomplex is formed by mixing PLLA and PDLA in the solution state or by melt mixing of PLLA and PDLA under heat. However, the method by mixing of PLLA and PDLA solutions requires evaporation of the solvent after the mixing and production process is therefore laborious, resulting in high cost of the polylactic acid stereocomplex, which is problematic. Further, in the cases of melt mixing of PLLA and PDLA under heat, these need to be mixed at a temperature that allows sufficient melting of the polylactic acid stereocomplex, but such a temperature also causes thermal degradation reaction of polylactic acid, leading to decreased physical properties of the molded article, which is problematic. Further, in cases where high-molecular-weight PLLA and high-molecular-weight PDLA are melt-mixed under heat, the melting points of the polylactic acid homopolymers do not disappear even with a mixing composition ratio of 50:50, so that it is currently impossible to obtain a material having both heat resistance and durability.
On the other hand, as techniques that enable formation of a stereocomplex even with high-molecular-weight polylactic acid, polylactic acid block copolymers composed of PLLA segments and PDLA segments have been disclosed (JP 2003-238672 A, JP 2006-28336 A, 3: JP 2006-307071 A and JP 2009-40997 A).
In JP 2003-238672 A, PLLA and PDLA prepared by ring-opening polymerization or direct polycondensation were melt-mixed under heat to prepare a mixture, which was then subjected to solid-phase polymerization, to obtain a polylactic acid block copolymer.
In JP 2006-28336 A, PLLA and PDLA obtained by melt polymerization were melt-mixed under heat, and the resulting mixture was subjected to solid-phase polymerization, to prepare a polylactic acid block copolymer.
In JP 2006-307071 A, PLLA and PDLA were mixed at a temperature close to the melting point and subjected to solid-phase polymerization in the presence of crystals of the polylactic acids alone, to prepare a polylactic acid block copolymer.
In JP 2009-40997 A, PLLA and PDLA obtained by direct polycondensation were mixed at a temperature higher than the melting point, and the resulting mixture was subjected to solid-phase polymerization, to obtain a polylactic acid block copolymer.
In the technique of JP 2003-238672 A, melt mixing needs heating to a temperature higher than the melting point of the polylactic acid stereocomplex, so that decrease in the molecular weight of the mixture during melt mixing is problematic. Further, because of requirement of prolonged reaction in solid-phase polymerization, improvement of the productivity has been demanded.
In the technique of JP 2006-28336 A, high-molecular-weight polylactic acid block copolymers can be obtained only in cases where the mixing composition ratio between PLLA and PDLA was apart from 50:50. In such cases, due to low stereocomplex formation, the obtained polylactic acid block copolymer is unlikely to have improved heat resistance and crystallinity, which is problematic.
In the technique of JP 2006-307071 A, formation of a stereocomplex is controlled only by the kneading temperature, and partial melting is found during kneading. Therefore, the crystal properties of the mixture are insufficient and also variable. Further, a polylactic acid block copolymer prepared by solid-phase polymerization of this kneaded product also has insufficient crystal properties, which is problematic.
In the technique of JP 2009-40997 A, since the molecular weights of PLLA and PDLA used for kneading are not more than 50,000, prolonged reaction is required for achieving a high molecular weight by solid-phase polymerization. Further, since the yield after the solid-phase polymerization needs to be increased, improvement of the productivity has been demanded.
It could therefore be helpful to provide a method for producing a polylactic acid block copolymer that forms a polylactic acid stereocomplex having a high molecular weight and a high melting point.

Method for producing polylactic acid block copolymer


An aluminum alloy for internal-combustion engine pistons has good high-temperature strength and good abrasion resistance. It comprises from 2 to 5% by weight of copper, from 13 to 16% by weight of silicon, from 0.2 to 1.3% by weight of magnesium, from 1.0 to 2.5% by weight of nickel from 0.05 to 0.2% by weight of vanadium and from 0.004 to 0.02% by weight of phosphorus, with the balance of aluminum. To produce the piston, a melt of the aluminum alloy having the defined composition is cast and then aged under heat at 220 to 260.degree. C. for 3 to 5 hours (T5 treatment) or, after having been cast, heated at 480 to 510.degree. C. for 3 to 10 hours for solution treatment and then aged under heat at 240 to 260.degree. C. for 3 to 5 hours (T6 or T7 treatment).

1. Field of the Invention
The present invention relates to an aluminum alloy with good high-temperature strength and good abrasion resistance f or internal-combustion pistons, which is suitable for pistons to be used in internal-combustion engines such as diesel engines and gasoline engines, and also to pistons comprising the aluminum alloy.
2. Description of the Related Art
Hyper-eutectic Al--Si alloys that contain Si in an amount of not smaller than 12.6% by weight have a small thermal expansion coefficient and good abrasion resistance. While solidifying, the melt of such an Al--Si alloy produces primary crystals of pro-eutectic Si having high hardness. Therefore, the alloys are used for internal-combustion engine pistons that require high abrasion resistance. However, the machine workability of the alloys is poor since the growth of pro-eutectic Si therein is too great.
For effective utilization of energy resources, recently, it is desired to increase the combustion efficiency of internal-combustion engines. The increase in the combustion efficiency involves an increase in combustion temperatures, for which various parts that constitute the internal-combustion engines, especially pistons, require good high-temperature strength.
For conventional internal-combustion engine pistons, often used are eight types of aluminum alloys of JIS H5202 (AC8A, AC8B, AC8C). These are all Al--Si--Cu--Mg alloys, of which AC8A and AC8B additionally contain Ni. However, these conventional aluminum alloys have poor high-temperature strength.
Japanese Patent Publication (JP-B) Sho-60-47898 discloses an improved aluminum alloy which is prepared by adding V and/or Mo to an Al--Si--Cu--Mg alloy and which has good high-temperature strength while still having good castability intrinsic to the Al--Si--Cu--Mg alloy base.
Japanese Patent Application Laid-Open (JP-A) Hei-8-104937 discloses a method for improving both the high-temperature strength and the abrasion resistance of an Al--Si--Cu--Mg alloy by adding P, Ca, Fe and Ti to the alloy, in which the ratio of P and Ca to the other additives is controlled to fall between 0.5 and 50 by weight so that the action of P to produce fine pro-eutectic Si grains is protected from being attenuated by Ca and so that the action of Ca to improve the eutectic texture of the alloy is protected from being attenuated by P.
However, the techniques disclosed in these publications are still problematic in that the alloys proposed therein are not resistant to thermal loads to be applied to the proposed internal-combustion pistons, as their strength at high temperatures (especially, at 250 to 300.degree. C.) is poor, and that the thermal expansion coefficient of the alloys is large and the abrasion resistance thereof is poor, as the uppermost Si content of the alloys is limited to 13%.
Also known are nine types of aluminum alloys of JIS H5202 (AC9A, AC9B) having a low thermal expansion coefficient and improved abrasion resistance which, however, are still problematic in that their high-temperature strength is low and their castability and workability is extremely poor.

Aluminum alloy for internal-combustion piston, and aluminum alloy piston


Techniques for attaching a replacement chip to an imaging cartridge are described. a method of replacing a component of an imaging cartridge includes: providing the imaging cartridge including a chip and a chip holding structure holding the chip, the chip holding structure including a left upper flange, a right upper flange, a rear retaining member, bottom supporting rails, a left forward retaining element extending from the left upper flange, and a right forward retaining element extending from the right upper flange; removing at least a portion of the left forward retaining element and the right forward retaining element to form a modified chip holding structure; removing the chip from the cartridge; installing a replacement chip in the modified chip holding structure; and attaching the replacement chip to the imaging cartridge.

The present invention generally relates to manufacturing, remanufacturing or repairing replaceable imaging components, and more particularly to apparatus and techniques for replacing an electronic circuit.
In the imaging industry, there is a growing market for the remanufacture and refurbishing of various types of replaceable imaging cartridges such as toner cartridges, drum cartridges, inkjet cartridges, and the like. These imaging cartridges are used in imaging devices such as laser printers, xerographic copiers, inkjet printers, facsimile machines and the like, for example. Imaging cartridges, once spent, are unusable for their originally intended purpose. Without a refurbishing process these cartridges would simply be discarded, even though the cartridge itself may still have potential life. As a result, techniques have been developed specifically to address this issue. These processes may entail, for example, the disassembly of the various structures of the cartridge, replacing toner or ink, cleaning, adjusting or replacing any worn components and reassembling the imaging cartridge.
Some toner cartridges may include a chip having a memory device which is used to store data related to the cartridge or the imaging device, such as a printer, for example. The imaging device may communicate with the chip using a direct contact method or a broadcast technique utilizing radio frequency (RF) communication. This chip is typically mounted in a location, such as a slot on the cartridge to allow for proper communication between the printer and the toner cartridge when the cartridge is installed in the printer. When the toner cartridge is being remanufactured, as described above, the chip provided by the original equipment manufacturer (OEM), such as Hewlett-Packard or Lexmark, may need to be replaced by a compatible chip developed by a third party. Due to the design of the toner cartridge, a certain part of the cartridge which helps hold the chip in place may need to be permanently removed in order to remove the OEM chip. With the part of the toner cartridge removed, a replacement chip would not be secured to the cartridge when it is installed. Thus, it would be desirable to provide techniques for attaching a replacement chip to such a toner cartridge.

Systems and methods for remanufacturing imaging components


The present invention proposes to use optimally a location method based on a WIFI type short-range telecommunication system and a satellite location system. The short-range telecommunication system is used to locate the terminal accurately within the building in which it is situated. The method uses a cartographic representation of the buildings in order to deduce from the position of the terminal a set of satellites that could be received by the terminal. The satellites are then acquired to synchronize the terminal to the satellite system. That synchronization is then used when the terminal leaves the building to acquire as quickly as possible the set of satellites of the satellite navigation constellation.

1. Field of the Invention
The present invention relates to a method for the accelerated acquisition of positioning satellite signals from a satellite location system for a mobile terminal moving from the interior to the exterior of a building, this method optimally combining a local telecommunication system inside the building and the satellite location system. A local telecommunication system means a wireless telecommunication local area network such as the Wireless Fidelity (WIFI) network conforming to the IEEE 802.11 standard, a system utilizing the Ultra Wide Band (UWB) local area network radio technology, or a system capable of operating under the short-range communication protocol known as Bluetooth. Satellite location system means a satellite positioning system of GPS (Global Positioning System), Galileo or Glonass type.
2. Description of the Prior Art
The invention also relates to a hybrid location system for the accelerated acquisition of positioning satellite signals for this kind of mobile terminal.
In a satellite positioning system utilizing GNSS (Global Navigation Satellite System) type receivers such as a GPS or Galileo receiver, the data signals enabling the receiver to calculate its position come from different satellites (at least four to determine the four unknowns x, y, z and t). It is well known by the man skilled in the art that positioning by such a system presupposes two types of processing in the receiver.
The first consists in acquiring the signal coming from at least four satellites, the second consists in evaluating the distance separating the receiver from the satellites from which the signal has been received. The interface between a Radio Navigation Satellite System (RNSS) and the user receiver relies on a radio signal itself relying on a spread spectrum technique well known to the man skilled in the art. Spread spectrum techniques, in their most routine form such as the C/A code GPS, F/Nav Galileo, rely on the use of a periodic pseudo-random code. In the context of the GPS, that code has a period of 1 millisecond (ms). This code is added to a digital navigation message, that message including a certain number of items of information necessary for the calculation of the position of the receiver, typically:                a time reference, well known in GPS under the name TOW (Time of Week) corresponding to the time of sending of the message,        the position of the satellite at the time of the sending of the message, well known in GPS under the name ephemerides,        certain corrections to be made to the onboard clock of the satellite, well known in GPS under the name clock corrections, aiming to correct the time reference relative to the global clock of the system,        certain propagation correction parameters, such as parameters for correction of the propagation speed of electromagnetic waves in the layers of the atmosphere (in particular the ionosphere),        the approximate position of the other satellites of the constellation via data known as almanacs.
The data bit rate is of course lower than the periodic spreading code bit rate. In the GPS SPS (GPS Satellite Positioning System) signal, the data bit rate typically rises to 50 bits per second, whereas that of the code is 1.023 million chips per second. A complete code being constituted of 1023 chips (i.e. 1 ms). All of the data added modulo 2 to the spreading code is transmitted on a carrier. In GPS, the carrier is typically at 1.57542 GHz.
The determination of the position of the receiver is represented in FIG. 1. The principle consists in a receiver [4] determining the distance separating it from at least three satellites of the constellation referenced by satellites [1], [2] and [3] (three satellites for location in two dimensions and four satellites for location in three dimensions). Once these distances [d1], [d2] and [d3] have been determined, the receiver can determine its position at the intersection of the spheres whose center is the position of each of the satellites themselves and whose radius is given by the distance [di]. The distance measurement is effected by measuring the time of arrival of a radio signal coming from the satellite. It follows that the essential information coming from the satellite via the navigation message that the receiver must process consists of the pair (sending TOW, position of the satellite at the time of sending). The satellite transmits in its navigation message its ephemerides (Keplerian parameters) enabling the receiver to calculate the position of the satellite in a frame of reference linked to the Earth. In the GPS case the ephemerides consist of 16 parameters.
M0Mean anomalyDnMean displacementEEccentricity(A)½Root of half major axisOMEGA 0Longitude of ascending nodeI0InclinationWArgument of perigeeOMEGA DOTTime derivative of right ascensionI DOTTime derivative of inclinationCucCosine amplitude of harmonic of latitudeargument correction termCusSine amplitude of harmonic of latitudeargument correction termCrcCosine amplitude of harmonic of orbitradius correction termCrsSine amplitude of harmonic of orbitradius correction termCicCosine amplitude of harmonic ofInclination angle correction termCisSine amplitude of harmonic ofInclination angle correction term
These parameters are repeated every 30 seconds in the navigation message.
The position of the satellite being obtained, it remains for the receiver to detect the time of sending of the message in order to deduce the propagation time of the wave and then the distance separating it from the satellite, and thus the radius of one of the three necessary spheres. As indicated hereinabove, the time also forms part of the content of the navigation message broadcast by the satellite. That time is repeated every 6 seconds. However, it is necessary to apply a satellite clock correction to the time read in the navigation message in order to transpose the transmitted time into a system reference common to all the satellites. This correction is transmitted every 30 seconds.
In conclusion, it is clearly apparent that a receiver can be in a position to determine its position only at the end of a minimum time of 30 seconds after having acquired the signal. The acquisition of the signal means the whole of the first operation to be effected by the receiver, which enables it to be synchronized in frequency and in time to the bit streams transmitted, an essential phase for the demodulation of the navigation message. For the receiver, acquisition consists in effecting a time-frequency search of the energy of the signal coming from the satellite. Locking onto the frequency of the signal from the satellite consists for the receiver in being tuned to the frequency at which the signal from the satellite is received. The receiver has three uncertainties leading it to effect this search:                Doppler effect linked to the mobility of the satellite,        Doppler effect linked to the mobility of the user,        uncertainty linked to the accuracy of the receiver clock.
For the receiver, time locking consists in identifying a code transition in the received signal. The spreading code in the case of the GPS being periodic with a period of 1 ms, the time search is effected with a 1 ms horizon. Once the code transition has been identified, the man skilled in the art knows how to identify a bit transition and then the frame synchronization broadcast in the navigation message.
This time-frequency search is very costly in terms of receiver complexity and limits commensurately the performance of the receiver.
To summarize, the time taken by a receiver to provide a first position is constrained by a very costly first phase of seeking time-frequency synchronization and also by the reading of basic information in the navigation signal (greater than 30 s).
The method known to the man skilled in the art for alleviating this problem is known as Assisted GPS or Assisted GNSS. This method consists in coupling a cellular telecommunication system and a satellite navigation signal receiver. This method is described in FIG. 2. It assumes that the satellite navigation signal receiver is coupled to a cellular telecommunication receiver (terminal) [11]. A network equipment commonly called the assistance data server [8] listens continuously to the satellites of the satellite constellation via a radio signal [6a] and a control antenna referenced [7]. The information from the navigation message from each satellite is then stored by the server [8]. When the receiver [11] is searching for its position, it requests a certain number of items of assistance data by means of a call via a base station [10] of the cellular network [9] to the assistance data server. The assistance data is then returned by the server [8] to the receiver [11] via the base station [10]. This assistance data facilitates the processing of the signal [6b] received by the receiver [11] coming from the satellite [5] and confers on the receiver performance that is enhanced, inter alia, in terms of calculation time. In fact, the assistance data may be of the following type:                Content of the navigation message broadcast in the signals [6b] and [6a]. The content is returned at a bit rate much higher than the bit rate of the navigation message. The time taken to route the data essential to the determination of the position is therefore changed from 30 seconds to 1 to 2 seconds.        Pre-location of the receiver [11]. In fact, the receiver [11] being connected to the base station [10], the server [8] is in a position to know that the receiver is in the vicinity of the base station [10]. In a GSM type network, the dimension of the cells is typically less than 35 km.        A time reference. The server [8] receiving the data from the satellite [5] is in a position to know the satellite system time and therefore to broadcast it to the receiver [11]. Most cellular communication networks being asynchronous, the time reference transmitted can achieve an accuracy only of the order of 2 to 3 seconds.        Different types of corrections: propagation speed corrections, satellite onboard clock correction, local propagation correction, etc.
The knowledge of a pre-location, of the ephemerides of the satellites and of an approximate time reference enables the receiver to calculate the Doppler effect of the satellites in view, greatly reducing the uncertainty in terms of frequency to be swept during the acquisition phase. Similarly, the ephemerides of the satellites being known via the call to the server [8], it becomes unnecessary for the receiver [11] to demodulate this data in the navigation message [6b], which eliminates the constraint of 30 seconds previously highlighted for calculating the position. It then suffices for the receiver to determine a time event in the signal [6b] from the satellite, in other words to find the spreading code transition and then the transmitted time, the TOW in the GPS signal which recurs every 6 seconds. There is therefore clearly a significant improvement in performance, as much with regard to the time necessary for the calculation of a location point as with regard to the sensitivity. Sensitivity means the minimum power of the signal received by the receiver enabling it to perform adequate processing.
The assistance example is provided in a GSM type cellular network, it goes without saying that it may be extended to other systems such as WIFI, WIMAX type systems.
However, even used in an assistance mode as referred to hereinabove, satellite location systems suffer from a limitation linked to the environment of the receiver and more particularly linked to the radio attenuation of the materials surrounding the receiver. These limitations are particularly revealed inside buildings.
The Research & Development teams of the Applicant are the first to have considered, for the interior spaces of buildings, triangulation techniques based on communication systems such as WIFI, WIMAX or UWB. The technology in widest use at the present time is, furthermore, based on triangulation using WIFI signals. This triangulation is effected by the receiver, which measures the distance separating it from various access points. The distance measurement may be established by a power measurement, for example. This measurement of the power received from a given access point enables a distance to be deduced by comparison with a model of attenuation as a function of distance. An alternative approach relies on measuring the time of arrival, in all respects identical to the method employed in satellite location systems. It is to be noted that systems, well known to the person skilled in the art, rely on a calibration of the radio environment, enabling the association with each position in a building of a characterization of the powers received from each access point visible from that position. A receiver measuring a configuration of powers received from all the access points surrounding it can determine its position thanks to this prior calibration. This technique is well known under the name of "Finger Printing".
The limitations of these latter systems are many: on the one hand, they necessitate a large number of access points in a building, but they also no longer function immediately the receiver leaves the building, outside which the WIFI access points are no longer visible from the terminal.
The Research & Development teams of the Applicant therefore considered coupling a WIFI, WIMAX or UWB receiver to an SPS (Satellite Positioning System) receiver of the GPS or Assisted GPS type. This coupling enables location inside the building but also outside. Nevertheless, the coupling does not enable an optimum continuity of service and, in many environments, offers less than optimum location performance. In fact, at the time of the transition from the interior of the building to the exterior of the building, the changeover from location based on local communication signals (WIFI, WIMAX, UMB) to location based on satellite signals is affected with a latency linked to the acquisition of the satellite signals, as previously explained. This latency is at least 30 seconds, as demonstrated hereinafter. It leads to an interruption in the continuity of the location service.

Method for the accelerated acquisition of satellite signals


A new fiber position monitoring method for sequential FBG UV-writing processes with a reference phase mask as the phase reference is proposed. Also, the new method by probing a reference phase mask can overcome the optical alignment difficulties in using reference fiber as well as provide more signal power for achieving better monitoring accuracy. Moreover, the present invention provides a method for sequentially joining a plurality of grating sections into a fiber grating longer than a phase mask.

1. Technical Field
The present invention relates to a method for manufacturing a complicated fiber grating by probing a diffraction of a phase mask. More particularly, the present invention relates to a method for manufacturing a long-length fiber Bragg grating (FBG) having a complicated structure, and a method for manufacturing a sequentially joined fiber grating longer than a phase mask in order to reduce errors in manufacturing fiber gratings. The present invention further provides a method for sequentially joining a plurality of grating sections into a fiber grating longer than a phase mask.
2. Description of Related Art
In recent years, many methods have been proposed for manufacturing a long-length fiber grating having a complicated structure, including the moving fiber-scanning beam technique and the sequential writing technique. When these two techniques are applied to a UV writing process, a He—Ne laser interferometer is required to track the position of an optical fiber. However, while manufacturing a long-length fiber grating, an accumulative error in the fiber position may occur during exposure due to a drifting of fringes generated by the interferometer and an inaccurate estimation of grating periods. This error has great impact on the manufacturing process and adds to the difficulties in manufacturing fiber Bragg gratings having complicated refractive-index changes and phase shift structures.
A patent application was filed in Taiwan by the present inventors of a method for manufacturing a fiber Bragg grating (Taiwan Patent Application No. 094115916; filed on May 17, 2005), wherein a phase distribution of a reference fiber grating is probed before each overlapping UV exposure. In this method, a feedback system is employed to probe a phase distribution of the reference grating at each locating point, so that the phase distributions of the reference grating before and after the reference grating is moved can be controlled to be consistent, ensuring that a phase of each written grating section is continuous from a phase of a previous grating section. However, the reference grating has a very small fiber core radius and a low first-order diffraction efficiency, making it difficult to calibrate the accuracy of position monitoring.
Furthermore, it is known from numerical simulation results that, for a subsequent fiber grating to have a frequency spectrum of a desired quality, a period mismatch between a period of the grating used for position monitoring and a period of UV fringe writing must be smaller than 5%. For ease of contrast, the prior art techniques mentioned in the first paragraph of this section are summarized below in comparison with the present invention to demonstrate their respective pros and cons.
(1) Taiwan Patent No. 434431
According to the method of this patent, a light beam is used to directly write a grating into a moving waveguide. Without using a phase mask and the interference technique, the grating is written in a point-by-point manner, whose refractive index is changed along the waveguide solely by controlling a moving speed of the waveguide. This method is suitable only for a long-period fiber grating and not applicable to a short-period fiber Bragg grating.
(2) U.S. Pat. Nos. 6,834,977 and 6,813,079
In these two patented methods, a grating is written into an optical fiber through a phase mask, section by section, by exposure to a continuous UV writing beam in an overlapping manner. Besides, an interferometer is used to monitor a position of a translation stage at each locating point. However, using the interferometer to monitor a writing location on the optical fiber leads to an accumulative error and requires accurate calibration of a period of the UV writing beam in advance. In the present invention, a grating is sequentially written in a section-by-section manner by probing a phase of a reference fiber grating, wherein a standard phase distribution is provided as a reference for writing. Therefore, according to the present invention, there are no accumulative error-related problems, and the accuracy of period calibration does not influence the manufacturing process significantly.
(3) U.S. Pat. No. 5,945,261
In this patented method, which utilizes the principle that an optical fiber exposed to a UV light will produce a fluorescent light, a grating section is created in advance by UV exposure and, by probing an intensity of the fluorescent light as a feedback system, a position of a translation stage is adjusted according to the fluorescent reaction of this pre-exposed grating section, so that a very long grating can be sequentially formed without phase discontinuity. And yet this method does not allow arbitrary insertion of phase shifts. According to the present invention, however, an arbitrary phase shift can be easily added to any location.
(4) U.S. Pat. Nos. 6,753,118 and 6,801,689
In the methods of these two patents, a feedback system is provided to compensate for drawbacks associated with gratings written by section-by-section, overlapping exposures. More particularly, a spectral response of a written grating is used to calculate corrections. However, as it is difficult to perform real-time monitoring with these methods, they are more suitable for regenerating written gratings. In contrast, the present invention allows real-time adjustment of phase distributions at each locating point, so that a grating can be completely created by writing with a UV writing beam only once.
(5) U.S. Pat. No. 5,830,622
In this patented method, refractive indices are adjusted by additional UV exposures at predetermined locations to introduce additional phase shifts. Therefore, scanning must be conducted for a second time, which is rather time consuming. In addition, the desired phase shifts to be introduced are hard to obtain in a section-by-section manner. In the present invention, however, an arbitrary phase shift can be easily added to any location without additional UV exposures.
(6) Paper published in Electronics Letters (1995), p. 1490
In this paper, grating writing is performed with a moving optical fiber and a phase mask. A fiber grating created by this method is limited in length by a length of the phase mask, while a resolution of a written pattern is affected by a limit on a moving speed of the optical fiber. In contrast, in the present invention, a grating is sequentially written in a section-by-section manner by probing a phase of a reference fiber grating. Therefore, the grating is not limited in length by a phase mask while a resolution of a written pattern is controlled by a writing time.
(7) Paper published in Journal of Lightwave Technology (1997), p. 1419
In this paper, a grating is also written by overlapping exposures in a section-by-section manner while an interferometer monitors a position of a translation stage at each locating point. However, a UV pulse is used in this paper as a writing beam, and a pulse laser causes additional noise problems. The present invention causes no such problems because a grating is sequentially created in a section-by-section manner by switching on and off a continuous UV writing beam.
(8) Paper published in Applied Optics (2002), p. 1051
In this paper, a grating is also written by overlapping exposures in a section-by-section manner while an interferometer monitors a position of a translation stage at each locating point. Although a continuous UV beam is used as a writing beam, the technique of using the interferometer to monitor a writing location on an optical fiber results in an accumulative error, which requires calibrating a period of the writing beam in advance. In contrast, according to the present invention, a grating is sequentially created in a section-by-section manner by probing a phase of a reference fiber grating, so that there are no accumulative error-related problems.

Long-length fiber Bragg creating sequential UV writing by probing phase mask


The invention relates to salts of (7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid which are useful for treating diseases affected by the activation of the IP receptor, pharmaceutical compositions that contain the salts and processes for preparing the salts are also described.

This invention relates to novel salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid, a process for their preparation and their use in pharmaceutical compositions.
International patent application PCT/EP2011/062028 (WO2012/007539) discloses certain heterocyclic compounds that are active IP receptor agonists and their use in treating various conditions or diseases affected by the activation of the IP receptor, including, for example, pulmonary arterial hypertension. One of those heterocyclic compounds is 7-(2,3-di-p-tolyl-7,8-dihydropyrido-[2,3-b]pyrazin-5(6H)-yl)heptanoic acid, which has the following structure:

International patent application PCT/EP2011/062028 (WO2012/007539) discloses a process for preparing 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid and the corresponding mesylate salt.
Pulmonary arterial hypertension (PAH) is a life-threatening disease characterized by a progressive pulmonary vasculopathy leading to right ventricular hypertrophy. Exogenous administration of an agonist of the IP receptor has become an important strategy in the treatment of PAH. (See, e.g., Tuder et al., Am. J. Respir. Crit. Care. Med., 1999, 159: 1925-1932; Humbert et al, J. Am. Coll. Cardiol., 2004, 43:13 S-24S; Rosenzweig, Expert Opin. Emerging Drugs, 2006, 11:609-619; McLaughlin et al, Circulation, 2006, 114:1417-1431; Rosenkranz, Clin. Res. Cardiol., 2007, 96:527-541; Driscoll et al, Expert Opin. Pharmacother., 2008, 9:65-81.).
A preferred route of administration of salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid in the treatment of pulmonary arterial hypertension is pulmonary delivery by inhalation.
The free form of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid has physical properties, including poor solubility and stability, that give rise to significant technical problems when manufacturing and formulating it for use as a pharmaceutical, particularly as an inhalable product, for example an inhalable dry powder.
The mesylate salt form of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid is undesired mainly for toxicological reasons, not in respect of pure methanesulfonate (mesylate) salts, but rather for certain corresponding sulfonic acid esters that are known to exert genotoxic effects. Such esters can be formed during the synthesis of the drug substance or during the crystallization of the salt, or during storage, especially if the crystallization solvent contains alcohols, such as methanol, ethanol or propanol. They can also be formed when alcoholic solvents are used for the preparation of the dosage form.
It has now been found that at least some of issues can be overcome by preparing certain novel salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid or at the very least such salts provide useful alternatives to the free form and the mesylate salt form.

Salts of 7-(2,3-di-p-tolyl-7,8-dihydropyrido[2,3-b]pyrazin-5(6H)-yl)heptanoic acid as IP receptor agonists


There is provided a receiving device including a receiving unit configured to receive a stream of a content to be distributed live, an analysis unit configured to analyze fragmented text information corresponding to subtitle data included in the received stream, and a control unit configured to control display of first text information so as to allow the display to be continued when second text information out of the text information is displayed based on a result of the analysis, the second text information being started to be displayed temporally after the first text information is displayed.

With the proliferation of the Internet in recent years, various services related to Internet streaming are provided such as IPTV (Internet Protocol TeleVision) for distributing videos, for example, by using IP (Internet Protocol). As a move toward standardization in Internet streaming, methods applied to VOD (Video On Demand) streaming and live streaming by HTTP (HyperText Transfer Protocol) streaming are being standardized. A MP4 file format is a highly promising format for container layers.
When subtitle data is stored as a component of a stream, a subtitle is displayed based on a file which stores the subtitle data (for example, see Patent Literature 1).
Utilizing TTML (Timed Text Markup Language), which has been standardized by W3C (World Wide Web Consortium), is becoming a standard for displaying subtitles. The TTML of the W3C is being increasingly adopted by other standardization organizations, and has received attention as a Timed Text-based promising format.
It is said that TTML is an XML (Extensible Markup Language) document, and thus it takes a relatively long time for processing. Thus, when an XML document is applied to live streaming, chunked TTML document instances, which are continuously generated as fragments in a short time, must be processed in real time, and so an idea needs to be implemented in a format or a processing system.
For this reason, at the present, it is considered that a TTML storing method for enabling real-time processing is indispensable in DASH (Dynamic Adaptive Streaming over HTTP) which is a prospective standard for an adaptive streaming format and in MP4 which is the main file format for streaming.

Receiving device and method of controlling the same, distribution device and distribution method, program, and distribution system


Provided are a chip packaging method and a chip packaging structure. The passivation layer is arranged on the pads of the wafer, then the first bonding layer is formed on the passivation layer, and the second bonding layer is formed on the substrate. The substrate and the wafer are bonded and packaged together by bonding the first bonding layer and the second bonding layer. The pads are only used as a conductive structure, not as a bonding layer due to the passivation layer arranged between the pads and the bonding layer. The through silicon via is arranged at the position above the pad and avoiding the bonding layer, so as to connect the functional circuit region between the wafer and the substrate to the outside of the chip packaging structure.

Wafer bonding process is commonly used in packaging a semiconductor chip, and two wafers are bonded together with bonding materials. In conventional technology, various methods are used to connect functional circuits on the bonded wafers to the outside, thus realizing signal transmission.
With the decrease of the volume of semiconductor devices, Through Silicon Vias (TSV) technology has gradually become a mainstream technology. Reference is made to FIG. 1, which is a schematic diagram of a chip packaging structure with a surface acoustic wave filter formed by TSV in the conventional technology. In FIG. 1, a wafer 01 and a packaging substrate 02 are bonded together by bonding glue 03, and the circuit inside the structure is connected to outside of the chip by filling the conductive material 04 and the copper pillar 05 in the TSV, and then a ball is mounted to form a complete filter chip.
However, with the decreases of the volume of the chip, the size of the circuit in the above structure is also required to be reduced, resulting in not ensuring the circuit performance

Chip packaging method and chip packaging structure


A method for installing ActiveX controls is disclosed. The method comprises transmitting a webpage to a user client, the webpage containing information of an ActiveX control necessary for the operation of the webpage in the form of a parameter; and receiving ActiveX control request information included in the parameter from the user client; wherein the webpage contains information of an integrated installer ActiveX control, which includes a module for installing the ActiveX controls necessary for the operation of the webpage in the form of an OBJECT tag, and contains script, which calls the module of the integrated installer ActiveX control and controls the installation of the ActiveX controls necessary for the operation of the webpage; and through the control of the script, the user client determines whether or not the ActiveX controls necessary for the operation of the webpage is installed and downloads ActiveX controls that need to be installed.

1. Field
The present invention relates to a method for installing program modules for operating a webpage, and in particular, to a method for installing ActiveX controls for operating a webpage.
2. Description of the Related Technology
ActiveX controls are reusable software components that can be used in connection with web pages over the Internet. ActiveX controls can be downloaded and executed by a Web browser. ActiveX controls can be developed in a variety of languages, including C, C++, Visual Basic, and Java. ActiveX controls allow provision of interactive web services.
In prior art, ActiveX control data was inserted in a webpage in a form of OBJECT tags. An example of ActiveX control data inserted in a webpage is as follows.                <OBJECT ID="ChatObj" CLASSID="CLSID:253380F7-1A0F-4C11-B218-C0E7E8E8C940" width=0 height=0 codebase="http://188.8.131.52/control/entoichatctrl.cab#version=1,0,1,54">
When ActiveX control data is inserted in a webpage as described above, a web browser displays a security warning message and then inquires the user whether to install the ActiveX control of the data included in the webpage.
These security warning messages incur uneasiness for inexperienced computer users. In many cases, users intentionally or inadvertently fail to install even a crucial ActiveX control for the operation of the webpage and are denied web services. In particular, as the security warning messages are recently being displayed on the upper portion of a web browser and not in a form of pop-ups, ActiveX controls are often not installed, even in cases where it is necessary to install the ActiveX controls, because the security warning messages go unnoticed.
When ActiveX controls are embedded in a form of OBJECT tags, a web browser displays security warning messages for security purposes. Since a warning message which requests the user's consent is displayed for each webpage of a service provider, even for a trusted service provider, users experience inconvenience of repeatedly clicking consent buttons for each page to install the ActiveX controls.


A tool is provided for modifying the code of a multi-threaded computer program undergoing testing. The program executes in an environment that has a governing memory model. It is assumed that there is a global heap and a thread-local heap, which are synchronized from time to time. The modifications are of two types: (1) code instructions are reordered while remaining in compliance with the memory model; and (2) thread-local variables are added to functions, together with inserted heap synchronizing instructions. The modified programs are then used by a test generator to prepare test cases for execution. The modifications have the effect of changing the interleavings that occur among different threads, and increase the likelihood of exposing flaws that may become evident under different memory models.

1. Field of the Invention
This invention relates to testing computer software. More particularly, this invention relates to testing software, which runs concurrently as multiple processes or threads, or on distributed processors.
2. Description of the Related Art
The main problem in testing a concurrent computer program, which executes as a plurality of threads or operates on a plurality of distributed platforms, is nondeterminism: two executions of such a program may yield different results. Most of the work in the field of concurrent testing has been focused on detecting race conditions. However, race conditions have a low probability of manifesting themselves, and even when they do, it is not always an indication of a fault. In any case, identifying race conditions is insufficient. It is possible that a program without races contains concurrent bugs, e.g., bugs due to incorrect usage of message-based synchronization.
Another approach to testing software is disclosed in the documents O. Edelstein, E. Farchi, Y. Nir, G. Ratsaby, and S. Ur., Multithreaded Java Program Test Generation, IBM Systems Journal, 41(1):111-125, 2002, and S. D. Stoller, Model-checking Multi-threaded Distributed Java Programs, in Proceedings of the 7th International SPIN Workshop on Model Checking of Software, pages 224-244, New York, 2000, Springer Verlag, which are herein incorporated by reference. The problem of generating different interleavings for the purpose of revealing concurrent faults was approached by seeding the program with conditional sleep statements at shared memory access and synchronization events. At run time, random, biased random, or coverage-based decisions were taken as to whether to execute seeded primitives. However, neither race detection nor the seeding approach helps detect bugs related to multi-layer memory models if the tests are executed on one-layer memory implementations.
Furthermore, the space of possible temporal orders of instruction executions by different threads that may be scheduled by a runtime environment, known as interleavings, is an exponential function of the program size. In the typical testing environment, little coverage of the space of possible interleaving is achieved. The term "coverage" concerns checking and showing that testing has been thorough. Coverage is any metric of completeness with respect to a test selection criterion for the program-under-test. The definition of coverage events is usually specific to a program-under-test, and constitutes a major part in the definition of the testing plan of the program.
The problem of testing multi-threaded programs is further compounded by the fact that tests that reveal a concurrent fault in the field or during stress testing are usually long and run under variable environmental conditions. For example, on a given machine, tasks launched asynchronously by the operating system may alter the machine's environment sufficiently to affect the results of two different executions of the same multi-threaded program. As a result, such tests are not necessarily repeatable. When a fault is detected, much effort must be invested in recreating the conditions under which it occurred.
In particular, the semantics of different versions of the Java™ two-layer memory model are a constant source of programmer misunderstandings and concurrent bugs. The Java memory model is described in the document, The Java Language Specification, James Gosling, Bill Joy, Guy Steele., Addison Wesley, 1996, and more recently in the document, JSR-133: Java Memory Model and Thread Specification, available on the Internet.
The memory model addresses the issue of heap synchronization. For various reasons, such as promoting efficient usage of multiprocessor machines, Java defines a two-layer model of the heap. Each thread operates on its own version of the heap, which in turn communicates with a global upper heap layer. The memory model defines the rules for this communication: when a thread executes certain operations, the executing environment must write the global heap onto the local one or vice versa. Another issue addressed by the memory model is instruction reordering. Many compiler optimizations are dependent on the ability of the compiler to reorder or duplicate instructions, issue prefetching requests, etc. However, a seemingly innocuous permutation at the thread level may change the program behavior because of interaction with other threads. Again, it is the responsibility of the memory model to define which permutations are allowed and which are not. The standard proposed in the above-noted JSR-133 model permits different kinds of heap synchronization and instruction reordering rules than its predecessor. Thus, programs that worked correctly under the old Java memory model may malfunction when run under JSR-133.
It is anticipated that the problems outlined above will become even more acute as new computer chips are equipped with two or more processors, and runtime implementations make use of the two-layer memory model.

Using code motion and write and read delays to increase the probability of bug detection in concurrent systems