A method is provided for determining an installation location. The method includes: providing a machine-readable description of the application to be installed; enhancing the machine-readable description with further requirements and/or properties; linking the application to be installed with an object identifier which includes the enhanced description and the requirements and/or properties of the application to be installed; linking objects existing in the distributed network environment with, in each case, at least one further object identifier which describes at least one property of an object; storing the object identifiers of the application to be installed and of the objects in the distributed network environment in a database; receiving a query regarding the application to be installed; providing the stored object identifiers of the application to be installed and of the objects for an evaluation unit; and receiving a determined appropriate installation location from the evaluation unit.

It is known that applications within a distributed network environment (e.g., a data network in a production environment) are often to be installed on an appropriate host. The host may be part of an environment that provides computational capacities at a production site and for this purpose is arranged in the vicinity of production machines at the outer edge of a network (so-called "edge cloud"). A host is considered to be appropriate if application-specific criteria are satisfied.
An application may include a number of software components and may have requirements with respect to various components of the edge-cloud-based production environment and with respect to the network. The so-called "edge cloud" may have a heterogeneous structure and include one or more hosts in the vicinity of or within production environments. A host may be a computer platform or a computer unit (computer) that is appropriate for performing at least one application. A host may also be a network component or a switch.
Each individual host may in this case have different properties or capabilities, resources, or restrictions. In addition, the properties or capabilities of these hosts may vary depending on how they are used and where they are installed. The network also connects the hosts to end devices and services outside the network of the production environment. Such connections of the network may have different properties, e.g., different bandwidths, delays, and the like.
In industrial environments, such as factory automation, building automation, or Supervisory Control and Data Acquisition (SCADA), the nodes of small, embedded devices may extend as far as large servers. Networks may be high-speed local industrial Ethernet variants, switched, routed, wire-bound, or wireless. Industrial applications may have a multiplicity of requirements for communication, for example, with regard to real-time requirements, required redundancy, and the like.
A further problem is that a provider of software, which may or may not be bound to specific devices, faces the problem that it cannot require or demand a specific situation or scenario from the customer. The customer on the other hand may provide that a product ordered by it may be installed and operated at its premises.
In addition to this, a software component may have requirements inter alia with regard to the runtime environment, including the network performance itself, with respect to other components. A software manufacturer is able to express such requirements terminologically, for example, by a description such as: "The database is to be operated in the vicinity of the sensors". Moreover, a customer is able to automatically find the appropriate location, if there are a number of possibilities, for the installation and operation of the software component and for configuring the required network connection, for example with respect to virtual interfaces (e.g., VLANs; Virtual Local Area Networks).
Furthermore, a service or an application may require connections to various other points in a customer installation. For instance, the information required for setting up a virtual network for the software service may be derived. For example, a database may require a connection to the public Internet and also a connection to local sensors.
Lastly, by contrast with computer centers or consumer networks, industrial Internet of Things (IoT) installations may have many more different devices over a large area. These devices may on the one hand be very different, on the other hand similar devices may also occur in large numbers, for example, a small stored-program controller (SPC) may be installed several hundred times in one factory. As a result, the configuration for an application or software component to be installed is laborious and susceptible to faults, in particular, because a machine-readable description sufficient for this problem does not exist at present, or only in a rudimentary form.
US 2014/0344461 A1 discloses techniques for intelligent deployment of services in which cloud and service data are evaluated in order to develop a service deployment plan for deploying a service in a target-cloud processing environment. When dictated by the plan or by events that trigger deployment, the service is deployed to the target-cloud processing environment in accordance with the service deployment plan.
US 2017/0289060 A1 discloses a model-driven system which automatically deploys a virtualized service, including multiple service components, on a distributed cloud infrastructure. A master-service orchestrator in this case causes a cloud platform orchestrator to retrieve a cloud services archive file, extract a cloud resources configuration template and create cloud resources at appropriate computer centers as specified. The master-service orchestrator also causes a software-defined network controller to retrieve the cloud services archive file, to extract a cloud network configuration template and to configure layer 1 through layer 3 virtual network functions and to set up routes between them.
The publication "Topology and Orchestration Specification for Cloud Applications" (Version 1.0) discusses the formal description of service templates that are used for deploying services in an IT infrastructure.
The publication "MODACLOUDS: A Model-Driven Approach for the Design and Execution of Applications on Multiple Clouds" (Danilo Ardagna et al.) presents an approach based on a model-based development that aims to assist system developers and operators in using multiple clouds for the same system and migrating them when required.
The publication "Standards-based Function Shipping—How to use TOSCA for Shipping and Executing Data Analytics Software in Remote Manufacturing Environments" (Michael Zimmerman et al.) validates the practical feasibility of various modeling approaches based on a case study from the domain of manufacturing, which is based on the open-source TOSCA ecosystem, (Open TOSCA), which provides a modeling tool, a runtime, and a self-service portal for TOSCA.
US 2015/0100684 A1 discloses a system including an application model to characterize a specific application for deployment in a cloud, a deployment manager analyzing an application requirement for a given application based on the application model and guidelines associated with the given application to substantially match infrastructure resources in the cloud to fulfill the application requirement.

Method and system for determining an appropriate installation location for an application to be installed in a distributed network environment


In a rear view mirror for a motor vehicle with a housing connected with an air source, traversed by air guide channels, and holding a mirror glass, with the outlets of the channels being arranged along the edge of the mirror glass to allow air to escape opposite to the direction of forward travel of the vehicle, modified guidance and processing of the escaping air reduces the danger of contamination of the mirror glass by the wind blast as well contamination of the side window associated with the mirror. This is also intended to improve the flow resistance of the mirror as well as its noise behavior. For this purpose, a plurality of separate air channel outlets is provided that are located within a guiding device and/or are equipped with one that produces vorticized air streams that emerge and are stable at each of the air outlets.

The invention relates to an outside rear view mirror for a motor vehicle.
An outside rear view mirror is known from German patent document DE-OS 2017093 and from DE 88 02 009 U1. As a result of air mass flows guided rearward in the forward travel direction at the edge of the mirror glass out of the rear view mirror, the pressure and flow conditions in the area in front of the mirror glass and the adjoining vehicle side window are to be influenced in such fashion that particularly during rain no, or at least as few as possible, dirt particles strike the mirror glass and side window.
The air flows that emerge from the air guide channels that are closed circumferentially are located horizontally adjacent to one another. This means that air flows escape side by side at approximately the same velocity. Such a flow or flow layer is not especially stable so that changes in position of the flow layer occur frequently. This results in undesired noises and also to the fact that dirt particles, together with the air flow, can reach the mirror glass.
In a similar rear view mirror known from Japanese patent document JP 61 36 036 A, behind the rear view mirror, only air flows with approximately the same velocity adjoin one another.
In a rear view mirror known from German patent document DE 40 39 484 C2, circumferentially closed air guide channels are absent from the edge of the mirror. The elevations and depressions provided on the outer edge for air guidance do not extend over the entire depth of the outside mirror in the flow direction. As a result, the air flows strike an edge at which uncontrolled vortices develop.

Outside rear view mirror for a motor vehicle


The subject invention provides reliable messaging with and within a control environment. The systems and methods utilize a message broker that facilitates message exchange. The message broker can be located within an industrial controller, as a dedicated entity within a control environment and/or an entity external to the control environment. Messages transmitted from an industrial controller and/or the external entity can be routed through the message broker prior to reaching a destination, wherein the message can be stored in the message broker and subsequently obtained by a recipient. The message broker decouples the message sender (e.g., an industrial controller, an external entity . . . ) from the message recipient (e.g., an industrial controller, an external entity . . . ) such that messages can be successfully transmitted (to the message broker) regardless of a state of the recipient, and messages can be retrieved (from the message broker) regardless of a state of the sender.

Electronic commerce, or e-commerce, generally refers to business conducted over an electronic medium such as the Internet (e.g., through the World Wide Web, or Web). Electronic commerce transactions typically are facilitated through applications such as web services, electronic shopping carts, file transfer protocol (FTP), secure FTP, electronic data interchange (EDI), email, and Universal Description, Discovery, and Integration (UDDI), among others. Electronic commerce transactions commonly are differentiated based on the type of trading partners that are interacting. For example, commerce between a business and a consumer generally is referred to as business-to-consumer (B2C) commerce, whereas commerce between businesses generally is referred to as business-to-business (B2B) commerce. Integration servers can be utilized to couple business and/or consumer trading partners and coordinate communication therebetween. By way of example, two businesses that employ disparate operating systems and/or applications can utilize an integration server to interact across internal and external networked computer systems.
In many instances, e-commerce can leverage information obtained from control systems and/or affect control systems. For example, a consumer purchasing an automobile through a dealer's web site may desire to know the lead time associated with building an automobile with a customized set of options. The dealer may query its manufacturing plants to ascertain whether an automobile with those options has been built or is going to be built. The result along with additional information can facilitate determining when such automobile will arrive at the distributor. If the purchaser decides to place a custom order (e.g., where there is no plan to build a car with the desired combination of options), the custom specification can be provided to the manufacturing plant and utilized to automatically configure one or more control systems therein. For example, the customer may have specified the color green as the external color of the automobile. This data can be conveyed to a control system and utilized to automatically select a suitable paint gun (e.g., a paint gun associated with green paint) and/or green paint when the automobile is being assembled.
Control systems commonly employ one or more industrial controllers. A typical industrial controller is a special purpose processing device for controlling (e.g., via an automated and a semi-automated means) industrial processes, machines, manufacturing equipment, plants, and the like. Such controllers can execute a control program or routine in order to measure one or more process variables or inputs representative of a status of a controlled process and/or effectuate outputs associated with control of the process. For example, an output module can interface directly with a controlled process by providing an output from memory to an actuator such as a motor, drive, valve, solenoid, and the like. In distributed control systems, controller hardware configuration can be facilitated by separating the industrial controller into a number of control elements, each of which can perform a different function. Particular control modules needed for the control task can be connected together on a common backplane within a rack and/or through a network or other communications medium. Various control modules can also be spatially distributed along a common communication link in several locations. Data can be communicated with these remote modules over a common communication link, or network, wherein any or all modules on the network communicate via a common and/or an industrial communications protocol.
Controllers within a control system can communicate with each other, with controllers residing in other control systems and/or with systems and/or applications outside of a control environment (e.g., business related systems and applications). Conventionally, such communication is achieved through a retry approach, wherein a controller can transmit a message (e.g., a request, information . . . ) to another entity, and if the message is not accepted by the entity (e.g., the entity/recipient is busy, inoperable, unavailable, unresponsive . . . ), the message transmission is aborted and the message is re-sent at a later time, or discarded. In another conventional approach, a message queue and an indexing scheme is utilized, wherein messages are stored in an array and an array index determines which message is transmitted. With this approach, even if a message transmission fails, the index is incremented and an attempt is made to send a next message. Eventually, failed transmissions are either re-sent or discarded.
Thus, conventional techniques usually require synchronous-based messaging, wherein the sender and the recipient are available to engage in a message exchange session. This can lead to, among other things, failed communications (e.g., messages that are not received or acted upon), delayed responses (e.g., as a function of the time difference between a sent message and a re-send), and additional overhead (e.g., consumption of processing cycles to review stored notifications, schedule re-transmissions and re-send messages). Moreover, industrial automation PLC programs that include messaging rely on users creating and maintaining library of ladder logic to implement message retry logic, communication protocols in ladder code, and other inconveniences.


An angioplasty system and method for identification and laser ablation of atherosclerotic plaque at a target site in a blood vessel includes fluorescence analysis for identification of noncalcified plaque and calcium photoemission analysis for identification of calcified plaque. Calcified plaque is identified by time domain analysis of calcium photoemission. A high energy pulsed ultraviolet laser can be used for stimulation of fluorescence and for stimulation of calcium photoemission. The system is capable of distinguishing between calcium photoemission and a defective condition of optical fibers that are used to deliver laser energy to the target site. In an another embodiment of the angioplasty system, calcium photoemission is identified during a nonablative initial portion of the laser ablation pulse. When calcium photoemission is not identified, the laser ablation pulse is terminated during the initial nonablative portion thereof.

Transluminal angioplasty involves the nonsurgical widening of a passage through an artery that has been narrowed, or stenosed, by deposits of plaque or plaque-ridden tissue. One approach to transluminal angioplasty involves the use of laser energy to vaporize, ablate or otherwise remove the plaque deposits. A catheter containing one or more optical fibers is advanced through an artery until its distal end is positioned adjacent to an obstruction. Laser energy sufficient to ablate the obstruction is directed through the optical fibers. A catheter for removal of biological obstructions with laser energy is disclosed in U.S. Pat. No. 4,817,601, issued Apr. 4, 1989 to Roth et al. A laser catheter including multiple optical fibers and adapted to be guided to a target site by a guidewire is disclosed in U.S. Pat. No. 4,850,351, issued Jul. 25, 1989 to Herman et al. Laser catheter systems utilizing infrared wavelengths for tissue issued Apr. 17, 1990 to Sinofsky, and U.S. Pat. No. 4,950,266, issued Aug. 21, 1990 to Sinofsky. Wavelengths in the visible and ultraviolet wavelength ranges have also been utilized for removal of biological material.
When laser energy is used to vaporize or ablate atherosclerotic plaque, thermal damage to surrounding normal tissue is a serious risk. The diameter of arteries is on the order of one to a few millimeters, and the energy level used for ablation of plaque is sufficient to damage or destroy normal tissue. Due to the frequent bends in arteries, the distal end of a laser catheter may be directed at an artery wall rather than at obstructing material. Inadvertent perforation of an artery with laser energy can have serious consequences. The use of pulsed laser energy for tissue ablation, with pulse parameters selected to minimize the risk of thermal damage, is disclosed in U.S. Pat. No. 4,800,876 issued Jan. 31, 1989 to Fox et al.
Since the ablation procedure is performed with a catheter, the tissue being ablated cannot be directly observed. Endoscopic techniques are usually impractical, since the fiber optics for illumination and viewing would increase the diameter of the catheter and reduce its flexibility to an unacceptable degree. Fluoroscopic techniques permit the location of the catheter to be determined, but do not identify the type of tissue being removed.
Techniques have been proposed for distinguishing between plaque and normal tissue by stimulating fluorescence from tissue in an artery and analyzing the frequency spectrum of the fluorescence. U.S. Pat. No. 4,785,806, issued Nov. 22, 1988 to Deckelbaum, discloses the use of ultraviolet laser energy for stimulating fluorescence. Fluorescence intensity at selected wavelengths in the blue/green wavelength range is analyzed to distinguish between plaque and normal tissue. The use of a dye to enhance the contrast between the fluorescence from plaque and the fluorescence from normal tissue is disclosed in U.S. Pat. No. 4,641,650, issued Feb. 10, 1987 to Mok. The use of visible light to stimulate fluorescence from atherosclerotic plaque is disclosed in U.S. Pat. No. 4,718,417, issued Jan. 12, 1988 to Kittrell et al.
It has been recognized that atherosclerotic plaque may have different characteristics, depending on a variety of factors. In particular, calcified plaque is relatively dense and requires more energy for ablation, whereas noncalcified plaque is softer and is more easily removed. G. Laufer et al in Lasers in Surgery and Medicine, Vol. 9, 1989, pages 556-571, describe application of 308 nanometer excimer laser energy to various types of arterial tissue, including normal arterial tissue, fibrous plaque, lipid plaque and calcified plaque. The spectral emission from the tissue was studied. Laufer et al state that calcified plaque exhibits a spectral line shape that is quite different from that of uncalcified arterial tissue. The feasibility of spectroscopic target tissue characterization and a real time spectroscopically-guided device are suggested.
R. H. Clark et al in Lasers in Surgery and Medicine, Vol. 8, 1988, pages 45-59, describe research on laser spectroscopic measurements of cardiovascular tissue including laser Raman light scattering, laser-induced plasma photoemission, laser-induced fluorescence and photoinduced electron paramagnetic resonance. The photoemission from calcified coronary arteries is discussed. The authors suggest that the measurements can serve as monitors during the course of laser photoablation.
M. R. Prince et al in IEEE Journal of Quantum Electronics, Vol. QE-23, No. 10, October 1987, pages 1783-1786, describe the differences between laser ablation of calcified plaque and noncalcified plaque. The authors believe that a laser induced plasma creates a shock wave that assists in ablation of the calcified plaque.
P. Teng et al in Appl. Phys. B, Vol. 42, pages 73-78, 1987 describe studies of laser fragmentation of biliary calculi. The temporal and spectral characteristics of the flash of light accompanying fragmentation of gallstones were studied. Formation of a plasma is suggested.
It is desirable to provide an angioplasty system which is capable of accurately identifying and ablating both calcified and noncalcified atherosclerotic plaque. The system should minimize the risk of damage or perforation of normal arterial tissue.
It is a general object of the present invention to provide improved methods and apparatus for angioplasty.
It is another object of the present invention to provide methods and apparatus for identifying and ablating calcified and noncalcified atherosclerotic plaque.
It is a further object of the present invention to provide methods and apparatus for determining the presence of calcified plaque at a target site in a blood vessel by analyzing a time domain signal representative of calcium photoemission from tissue at the target site.
It is a further object of the present invention to provide methods and apparatus for identification of atherosclerotic plaque at a target site in a blood vessel utilizing analysis of fluorescence by noncalcified plaque and analysis of calcium photoemission by calcified plaque.
It is yet another object of the present invention to provide methods and apparatus for distinguishing between photoemission from calcified plaque and photoemission from a damaged optical fiber.

Angioplasty system having means for identification of atherosclerotic plaque


The present invention provides a terminal apparatus connectable to a communication network capable of comprising a plurality of different communication systems. The terminal apparatus comprises a coexistence header generation section of generating at least a portion of a head portion of a frame used in a communication system to be suppressed from frame transmission of the plurality of communication systems, as a coexistence header, a coexistence header transmission section of transmitting the coexistence header generated by the coexistence header generation section in a manner which enables a terminal apparatus belonging to the communication system to be suppressed to receive the coexistence header, a coexistence header transmission timing determination section of determining a timing of transmitting the coexistence header, and a communication control section of causing the coexistence header transmission section to transmit the coexistence header generated by the coexistence header generation section at the timing determined by the coexistence header transmission timing determination section.

1. Field of the Invention
The present invention relates to a terminal apparatus for transmitting/receiving data on a communication network. More particularly, the present invention relates to a terminal apparatus for transmitting/receiving data on a communication network having a plurality of communication systems different from one another (hereinafter also simply referred to as "different communication systems").
2. Description of the Background Art
Conventionally, wireless LAN systems and power line communication systems have been commercialized as communication systems in which data is transmitted in packets among a plurality of terminals. For wireless LAN systems, there are IEEE802.11, IEEE802.11b and IEEE802.11g standards which utilize a 2.4-GHz band. These wireless LAN systems adopt different modulation techniques to improve communication speed every time the specification is extended. Further, the wireless LAN systems are standardized in a manner which enables the different standard systems to coexist and be connected to one another.
In IEEE802.11, an autonomous distributed access control is achieved by performing an access control called DCF (Distributed Coordination Function) using a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) scheme. In the CSMA/CA scheme, a terminal which tries to transmit a signal checks (carrier sense) the state of use of a wireless channel before transmission of the signal in order to avoid collision with a signal transmitted by another terminal. When the wireless channel is not used (idle), a signal is immediately transmitted. When the wireless channel is used (busy), transmission is postponed until the wireless channel is idle.
To determine whether or not the wireless channel is idle, IEEE802.11 defines an IFS (Inter Frame Space). When no signal is detected over the defined IFS time or more, a terminal which tries to transmit a signal determines that the wireless channel is idle. The IFS is defined to have a fixed length. A plurality of lengths of IFS may be defined. In this case, the priorities of terminals or frames are controlled by assigning each terminal an IFS having a length corresponding to the priority thereof.
FIG. 36 is a diagram for explaining a control of the priority using IFS. IFSs (SIFS, PIFS, DIFS) having different lengths are assigned to frames, depending on the priority. The priorities of the frames are increased in order of SIFS, PIFS and DIFS. For example, it takes a short time for a terminal which wants to transmit a frame assigned with the short IFS to determine whether or not the wireless channel is idle. Therefore, a frame assigned with the short IFS is transmitted earlier than a frame assigned with a low priority. Therefore, a frame having a high priority has more opportunities of transmission than a frame having a low priority.
When the wireless channel is busy, a terminal waits until the wireless channel is idle. When the wireless channel is idle, a backoff algorithm is executed so as to avoid subsequent collision. The backoff algorithm is used to avoid the collision of packets which is caused by simultaneous transmission by a plurality of terminals. The probability of collision is highest at a time immediately after a certain terminal completes transmission and a wireless channel is then transitioned from the busy state to the idle state. This is because terminals ready for transmission which recognizes that the wireless channel comes to be the idle state start transmitting a signal simultaneously.
FIG. 37 is a diagram for explaining an access control method using a conventional CSMA/CA scheme. Hereinafter, an access control method using a CSMA/CA scheme, to which the backoff algorithm is applied, will be described with reference to FIG. 37.
An access point AP and stations STA1, STA2 and STA3 always perform carrier sense and monitor the state of use of a wireless channel. Here, it is assumed that DIFS (Distributed IFS) is used as IFS. When the wireless channel is in the busy state, each station generates a random number within the range of zero to CW (Contention Window: a range in which random numbers from zero to uniform distribution are generated in the backoff algorithm). Each station determines a backoff time based on the random number thus generated. Thereafter, each station decreases the backoff time during a time when the wireless channel is idle. At a time when the decreased backoff time becomes zero, packet transmission is started. In FIG. 37, the backoff time of the access point AP is the first to become zero, and therefore, the access point AP transmits a packet. When another terminal starts transmission before the remaining time becomes zero, the other stations (in FIG. 37, the stations STA1, STA2 and STA3) become ready for transmission again. The remaining backoff time is decreased again from a time when the wireless channel becomes idle. In FIG. 37, by decreasing the remaining backoff time again, the backoff time of the station STA2 is the first to become zero, and therefore, the station STA2 transmits a packet. Note that a time until the wireless channel becomes idle is stored as an NAV (Network Allocation Vector) value in a header of a transmission packet. A terminal ready for transmission can know the next idle time by waiting for a time matching the NAV value stored in the transmitted packet. The NAV value varies depending on the length of data constituting a packet or a modulation rate used in transmission.
The backoff algorithm of IEEE802.11 is called a "binary exponential backoff algorithm". The range CW of a random number generated is given by parameters, i.e., a minimum value CWmin and a maximum value CWmax. In the initial random number generation, the value of CW is set to be CWmin. The CW value is doubled as the number of retransmissions is increased by one. After the CW value reaches CWmax, CW becomes a constant value. Thus, the CW value is increased with an increase in the number of retransmissions. In other words, as traffic increases and becomes denser, the number of variations of backoff time is increased. Therefore, data collision is more likely avoided.
When normally receiving a packet, a station returns ACK (Acknowledgement) to the sender after the SIFS (Short IFS) interval from the time of completion of the reception. SIFS is the shortest IFS. Therefore, the ACK signal is transmitted with the highest priority. After transmitting a packet, if an ACK signal is not returned within a predetermined time from the time of completion of data transmission, a terminal determines that the transmission has failed and retransmits the packet.
A physical layer of IEEE802.11 is divided into a PMD (Physical Medium Dependent) sub-layer and a PLCP (Physical Layer Convergence Protocol) sub-layer. The PLCP sub-layer is positioned between the PMD sub-layer and an MAC layer, and absorbs the difference among three modulation/demodulation schemes defined in the PMD sub-layer to unify the interface between the MAC layer and the physical layer. The IEEE802.11b standard is the conventional IEEE802.11 standard with an extended DS-SS scheme and is downwardly compatible with IEEE802.11. In the IEEE802.11b standard, 5.5 Mbps and 11 Mbps are defined as transmission rates in addition to 1M bps and 2M bps of the DS-SS scheme. The DS-SS scheme uses an 11-bit Barker code for spread spectrum modulation. In the IEEE802.11b standard, the transmission rate is increased by adding the CCK scheme which uses a complementary code. IEEE802.11b defines four transmission rates. In IEEE802.11b, the transmission rate of a preamble portion and a header portion is fixed to 1 Mbps. The header region stores information about a transmission rate used for a data portion. Thereby, data can be correctly demodulated by a receiver.
FIG. 38 is a diagram showing a packet structure of the conventional IEEE802.11b. In FIG. 38, "SYNC" is a field for indicating a synchronization signal and "SFD" is a field for indicating the start of a frame and the head of a physical layer, which is an abbreviation of "Start Frame Delimiter". These fields constitute a PLCP preamble portion.
"SIGNAL" is a field for indicating the transmission rate of the data portion. "SERVICE" is a field (CCK, PBCC) for identifying a high-speed modulation scheme. "LENGTH" is a field for indicating a time required to transmit data (unit: mS). "CRC" is a field for indicating a cyclic redundancy check code. These fields constitute a PLCP header portion.
The PLCP preamble portion and the PLCP header portion constitute a long preamble.
"MPDU" is a MAC protocol data unit and is a field for storing data. The data is modulated by any of 1-Mbps DBPSK (spread with a Barker code), 2-Mbps DBPSK (spread with a Barker code), and 5.5- or 11-Mbps CCK modulation.
"PPDU" is a PHY protocol data unit.
FIG. 39 is a diagram showing packet structures of IEEE802.11, 802.11b and 802.11g. The heads of the packet structures each have a 1-Mbps preamble which is DS-modulated. Since the preamble is DS-modulated, a terminal can recognize it no matter which standard is employed in the terminal. Data is subjected to DS modulation, CCK modulation or OFDM modulation, depending on a standard to which a destination terminal belongs. Thereby, the coexistence and compatibility of these standards are held.
As a power line communication system, HomePlug 1.0 has been developed and commercialized by HomePlug Alliance, US (see Yu-Ju Lin et al., A Comparative Performance Study of Wireless and Power Line Networks, IEEE Communication Magazine, April 2003, p54–p63). The power line communication system achieves 14-Mbps communication using a power line in a room.
FIG. 40 is a diagram showing a frame structure and a protocol of HomePlug 1.0. In FIG. 40, as with "DIFS" of IEEE802.11, "CIFS" is an inter-frame spacing. "Priority Resolution0" and "Priority Resolution1" are priority times. A terminal which transmits a symbol for a priority time has a higher priority than that of a terminal which does not transmit a symbol during the priority time. The two priority times can be used to indicate four priorities. Terminals having the highest priority can be transitioned to the subsequent "Contention" phase. In the "Contention" phase, an algorithm similar to the backoff algorithm of IEEE802.11 is executed to avoid collision. A terminal which has started earliest in the "Contention" period transmits the subsequent data packet. "Data" has "preamble" and "frame control" at a head thereof. These have functions similar to those of the PLCP preamble and PLCP header of IEEE802.11. "Frame body" has a variable length which varies between 313.5 μSec to 1489.5 μSec, depending on the data length and the modulation rate. A busy time substantially corresponding to the length of the "frame body" is stored in NAV information within the "frame control". A terminal which has received the "frame control" waits for the busy time indicated by the NAV before starting measuring CIFS for the next transmission.
As described above, the conventional IEEE802.11, IEEE802.11b and IEEE802.11g use the DS-SS scheme common to the preamble portion and the header portion, and apply a high-efficiency modulation scheme to data, thereby holding the compatibility and the coexistence. However, in this method, the growth rate of the throughput of data transmission in an upper layer is made very small in spite of the increased speed of the physical layer. This is because, as the speed of the physical layer is increased, a time occupied by the preamble portion and the header portion is relatively elongated.
FIG. 41 is a diagram for explaining that the time occupied by the preamble portion and the header portion is relatively elongated. As shown in FIG. 41, the preamble is DS-modulated in all of IEEE802.11, IEEE802.11b and IEEE802.11g, and therefore, a time required to transmit the preamble is the same. On the other hand, data is DS-modulated in IEEE802.11, CCK-modulated in IEEE802.11b, and OFDM-modulated in IEEE802.1g. Therefore, as the standard is extended, a time occupied by the preamble portion and the header portion is relatively elongated.
According to a quantitative calculation, in IEEE802.11b, the PHY speed is 11 Mbps, while the throughput of an upper layer is about 5 Mbps. However, even if the PHY speed is increased by a factor of about 5 to 54 Mbps, the throughput of the upper layer is increased by a factor of 2 to about 10 Mbps (Tetsu Sakata (NTT Access Network Service Systems Laboratories), Interface, P. 43, FIG. 32, Feb. 1, 2003, CQ Publishing). Particularly in VoIP (Voice Over IP: voice communication utilized in IP telephone or the like), a small amount of data (32 kbps, etc.) is regularly transmitted, so that the proportion of the header in each packet is further increased, resulting in very poor efficiency.
In the high-speed communication system of IEEE802.11b or later, DS-SS scheme packets of IEEE802.11 need to be received. In order to coexist with a conventional scheme, a conventional scheme transmission/reception circuit needs to be mounted. Therefore, the circuit area of LSI is increased, leading to an increase in cost. Particularly, the reception circuit needs to comprise components, such as an AGC circuit, an AD conversion circuit, a demodulation circuit, an error correction circuit and the like, which have a large influence on cost.

Terminal apparatus for enabling a plurality of different communication systems to coexist

Matsushita Electric Industrial Co., Ltd.


A rock-crushing rotary drill bit includes a body having a rock-crushing roller rotatably mounted thereon by bearings. The body includes a first flushing channel for conducting flushing fluid to flush the bearings, and a second flushing channel for discharging flushing medium outside of the bit body to flush away cuttings. The second flushing channel terminates in a discharge recess which defines a linear center axis. A nozzle is disposed at a downstream end of the discharge recess, and a valve element is disposed at an upstream end of the discharge recess. The valve element is spring-biased for closing the discharge recess, the valve element being openable against the spring bias in response to a sufficient pressure build-up of flushing medium within the second flushing channel. The valve element includes a guide structure for guiding the valve element for linear movement along the center axis of the discharge recess.

This application is based on and claims priority of Swedish Patent Application No. 0001434-0, filed Apr. 14, 2000, the disclosure of which is incorporated by reference herein.
The present invention relates to a rock-crushing rotary drill bit and a check valve therefor.
The placement of one or more nozzle-carrying passageways in a rotary drilling bit to conduct air or other drilling fluids from the central bore of the bit to the rotating cutters is well known. The drilling fluid thus directed serves to cool the cutters and to carry cuttings away from the cutters. However, the presence of these passageways makes it possible for cuttings and other foreign materials to enter the interior of the bit through the nozzle(s) when the circulation of the drilling fluid ceases and thus to impair the further operation of the bit, e.g., foul the bearings of the bit. This problem has been dealt with by placing check valves or filters in the interior bore and passageways of rotary drill bits. A drawback of such prior rotary drill bits is that fluid may still rise upwardly into the drill bit through the nozzle if the surrounding pressure during drilling is greater than the pressure in the drill bit, for example when the flow of flushing medium is terminated during the addition of additional sections of the drilling string.
In U.S. Pat. No. 3,685,601 that problem has been dealt with by means of a check valve positioned in the nozzle itself. The check valve comprises a spring-loaded closure plate hingedly mounted in a hollow body that forms part of the nozzle. The hinged closure plate opens and closes in an oscillating manner in the channel of the nozzle dependent on the direction of the flushing medium. Use of this type of hinged check valve has been insufficient due to premature breakages, e.g., due to metallic fatigue of the hinge.
Other prior art rotary drill bits shown in U.S. Pat. Nos. 4,457,384 and 3,089,551 are exemplary of check valves positioned in the central bore of the bit at the level of the external conical thread of the bit, thus allowing dirt to enter the bit.
One object of the present invention is to provide a rotary drill bit, which enjoys the advantages associated with prior techniques.
Another object of the present invention is to provide a rotary drill bit, which has an extended life.
Still another object of the present invention is to provide a rotary drill bit, which has a check valve with an inertia such that the bearing of the drill bit is flushed substantially clean before drilling is resumed.
Still another object of the present invention is to provide a rotary drill bit, which has a robust check valve that does not break due to metallic fatigue.
Still another object of the present invention is to provide a rotary drill bit, which minimizes the formation of cavitation in the flow of flushing fluid and thus reduces blasting damage.
A rock-crushing rotary drill bit comprises a body forming at least one leg, and a rotatable roller rotatably mounted on the at least one leg by bearings. The roller includes rock-crushing elements. The body further includes an external thread adapted for connecting the roller to a drill tube. A main channel in the body conducts flushing medium. A first flushing channel passes through the leg and communicates with the main channel for conducting part of the flushing medium to flush the bearings. A second flushing channel communicates with the main channel and includes a discharge recess for discharging another part of the flushing medium. The flushing recess defines a linear center axis. A nozzle is disposed at a downstream end of the discharge recess for directing flushing medium in a direction to flush away cuttings. A valve element is disposed at an upstream end of the discharge recess and includes a guide structure for guiding the valve element for linear movement along the center axis. The valve element is spring-biased to a closed state for closing the discharge passage, and is yieldable in response to fluid medium pressure acting thereagainst, for opening the discharge recess.
The invention is also directed to a check valve per se, wherein the valve element, and biasing spring, are mounted within a house that carries the nozzle at one end thereof.

Rock drill bit and a check valve therefor


An instrument for use in moving bone fragments of a bone fracture with respect to one another is disclosed. Preferably, movement of a portion of the instrument causes translational movement of a first bone fragment with respect to a second bone fragment. In certain embodiments, the instrument is used in conjunction with a bone plate and an elongate element, such as a K-wire. Methods for utilizing the instrument and moving bone fragments with respect to each other are also disclosed.

The present invention relates to the field of bone fracture repair, and more particularly, to a compression instrument for use in conjunction with a bone plate.
For many years, bone plates and other fixation means have been widely utilized by doctors and surgeons for repairing fractures formed in bones. Such fractures typically result in otherwise unitary bone structures being split into two or more fragments, with many of these bone fractures resulting in two separate fragments. Essentially, it has been the general practice to reset the different bone fragments to their original position, place a bone plate across the fragments, and affix the plate to each of the fragments through the use of screws or other fixation means. This allows the different fragments to reattach to one another through recalcification so as to permit the fractured pieces to be reformed into the original bone structure. During this process, the affixed bone plate preferably ensures that the fragments remain in their original position, and provides a certain level of support to the bone structure.
Although the above method of rejoining bone fragments caused by fractures has been widely utilized for many years, with overwhelmingly positive results, it is not free from any and all drawbacks. For example, while a simplified fracture repair method is basically described above, many fractures are far from simple. Often times, fractures of bones, such as long bones, are accompanied by other injuries to the body that make it difficult to reset or compress the different bone fragments to their original position. Thus, doctors or surgeons often struggle with the initial resetting of the different fragments of a fractured bone.
Therefore, there exists a need for a compression instrument for use in conjunction with a bone plate or other such device that aids in the resetting or compressing of fractured bone fragments.


A loudspeaker system comprising a diaphragm (101) and an electrostatic foil (108) mounted on top of the diaphragm (101).

Loudspeakers are technical devices which convert an electrical audio signal into a corresponding sound. The most widely used type of loudspeaker is the dynamic loudspeaker, in which sound is generated by a swinging diaphragm driven by an electromagnet, which oscillates in the external field of at least one permanent magnet. It uses a lightweight diaphragm, or cone, connected to a rigid basket, or frame, via a flexible suspension, commonly called a spider, that constrains a voice coil to move axially through a cylindrical magnetic gap. When an electrical signal is applied to the voice coil, a magnetic field is created by the electric current in the voice coil, making it a variable electromagnet. The coil and the driver's magnetic system interact, generating a mechanical force that causes the coil (and thus, the attached cone) to move back and forth, accelerating and reproducing sound under the control of the applied electrical signal coming from the amplifier.
There are also other technical concepts for realizing a loudspeaker. The most common alternative implementation of a loudspeaker is the electrostatic loudspeaker, in which not a magnet is used to drive the diaphragm, but the electrostatic Coulomb force is used. Those loudspeakers use a thin flat diaphragm usually consisting of a plastic sheet coated with a conductive material such as graphite near an electrically conductive grid, with a small air gap between the diaphragm and grid. The driving force is in contrast to a dynamic loudspeaker not the Lorentz Force but the electrostatic Coulomb-Force.


A process for recovering a hydrogen-rich gas and for increasing the recovery of liquid hydrocarbon products from a hydrocarbon conversion zone effluent by adsorption of the liquifiable products from a chilled gaseous stream with a chilled liquid stream is improved by an arrangement that uses a single refrigeration shell to provide independent temperature control of the chilled gaseous and the chilled liquid stream.

Various types of catalytic hydrocarbon conversion reaction systems have found widespread utilization throughout the petroleum and petrochemical industries for effecting the conversion of hydrocarbons to different products. The reactions employed in such systems are either exothermic or endothermic and, of more importance to the present invention, often result in either the net production of hydrogen or the net consumption of hydrogen. Typical of the net hydrogen-producing hydrocarbon reaction systems are catalytic reforming, catalytic dehydrogenation of alkylaromatics, and catalytic dehydrogenation of paraffins. Commonly employed net hydrogen-consuming reaction systems are hydrotreating, hydrocracking, and catalytic hydrogenation. Of the above-mentioned net hydrogen-producing and consuming hydrocarbon reaction systems, catalytic reforming ranks as one of the most widely employed.
With the operation of net hydrogen producing processes the hydrogen balance for the petroleum refinery or petrochemical complex may result in excess hydrogen, i.e., the net hydrogen-producing reaction systems produce more hydrogen than is necessary for the net hydrogen-consuming reaction systems. In such an event, the excess hydrogen may be sent to the petroleum refinery or petrochemical complex fuel system. However, because the excess hydrogen often has admixed therewith valuable components such as C.sub.3 + hydrocarbons, it is frequently desirable to recover these components by treating the excess hydrogen prior to its passage to fuel.
Because hydrogen is relatively expensive, it has become the practice within the art of hydrocarbon conversion to supply hydrogen from reaction systems which result in the net production of hydrogen to reaction systems which are net consumers of hydrogen. Occasionally, the net hydrogen being passed to the net hydrogen-consuming reactions systems must be of high purity due to the reaction conditions and/or the catalyst employed in the systems. Such a situation may require treatment of the hydrogen from the net hydrogen-producing reaction systems to remove hydrogen sulfide, light hydrocarbons, etc. from the net hydrogen stream.
It is well known that high quality petroleum products in the gasoline boiling range, including--for example--aromatic hydrocarbons such as benzene, toluene, and the xylenes, are produced by the catalytic reforming process wherein a naphtha fraction is passed to a reaction zone wherein it is contacted with a platinum-containing catalyst in the presence of hydrogen. By virtue of its wide application and its utilization as a primary source of hydrogen for the net hydrogen-consuming reactions systems, catalytic reforming has become well known in the art of hydrocarbon conversion reaction systems. Generally, the catalytic reforming reaction zone effluent comprising gasoline boiling range hydrocarbons and hydrogen is passed to a vapor-liquid equilibrium separation zone and is therein separated into a hydrogen-containing vapor phase and an unstabilized hydrocarbon liquid phase. A portion of the hydrogen-containing vapor phase may be recycled to the reaction zone. The remaining hydrogen-containing vapor phase is available for use either by the net hydrogen-consuming processes or as fuel for the petroleum refinery or petrochemical complex fuel system. While a considerable portion of the hydrogen-containing vapor phase is required for recycle purposes, a substantial net excess is available for the other uses.
Because the dehydrogenation of naphthenic hydrocarbons is one of the predominant reactions of the reforming process, substantial amounts of hydrogen are generated within the catalytic reforming reaction zone. Accordingly, a net excess of hydrogen is available for use as fuel or for use in a net hydrogen-consuming process such as the hydrotreating of sulfur-containing petroleum feedstocks. However, catalytic reforming also involves a hydrocracking function among the products of which are relatively low molecular weight hydrocarbons including methane, ethane, propane, butanes and the pentanes; substantial amounts of which appear in the hydrogen-containing vapor phase separated from the reforming reaction zone effluent. These normally gaseous hydrocarbons have the effect of lowering the hydrogen purity of the hydrogen-containing vapor phase to the extent that purification is often required before the hydrogen is suitable for other uses. Moreover, if the net excess hydrogen is intended for use as fuel in the refinery or petrochemical complex fuel system, it is frequently desirable to maximize the recovery of C.sub.3 + hydrocarbons which are valuable as feedstock for other processes.
Many processes for the purification of hydrogen-rich gas streams from the effluent of hydrocarbon conversion reaction zones are disclosed. Well known processing procedures for hydrogen-containing effluent streams include steps to remove potentially valuable C.sub.3 + product hydrocarbons from hydrogen-containing gas streams. U.S. Pat. No. 5,238,555, issued Aug. 24, 1993, discloses a process wherein the effluent from a reforming zone is separated into a hydrogen containing stream and a hydrocarbon effluent. Both streams are chilled and the chilled streams are contacted to absorb lighter hydrocarbons from the hydrogen-containing stream. U.S. Pat. No. 5,178,751 shows another arrangement for separating light hydrocarbons from a chilled hydrogen-containing stream recovered from a reforming zone using a chilled hydrogen stream. In U.S. Pat. No. 5,178,751 the hydrogen-containing stream and the hydrocarbon steam are admixed and chilled together in a single chiller, but the admixture of the streams precludes any independent control of the temperature of the gas and liquid phases.

Method of gas stream purification having independent vapor and liquid refrigeration using a single refrigerant


The invention provides an alignment measurement arrangement having a broadband source, an optical system and a detector. The broadband source is arranged to generate a radiation beam with a first and second range of wavelengths. The optical system is arranged to receive the generated radiation beam, produce an alignment beam, direct the alignment beam to a mark located on an object, to receive alignment radiation back from the mark, and to transmit the alignment radiation. The detector is arranged to receive the alignment radiation and to detect an image of the alignment mark located on the object. The detector furthermore produces a first and a second alignment signal, respectively, associated with said first and second range of wavelengths, respectively. The alignment measurement arrangement finally has a processor, which is connected to the detector. The processor is arranged to receive the first and second alignment signal, to determine a first and second signal quality respectively of the first and second alignment signal respectively by using a signal quality indicating parameter, and to calculate a position of the alignment mark based on the first and second signal quality.

A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. comprising part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the "scanning"-direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
Lithographic apparatus are known to use multiple alignment arrangements. Reference is, e.g., made to K. Ota et al., New Alignment Sensors for Wafer Stepper, SPIE, Vol. 1463, Optical/Laser Microlithography IV (1991), p. 304-314, and N. R. Farrar et al., Performance of through-the-lens/off-axis laser alignment systems and alignment algorithms on Nikon wafer steppers, SPIE Vol. 1673, Integrated Circuit Metrology, Inspection, and Process Control VI (1992), p. 369-380. All of the alignment arrangements use their own, distinct marks on, e.g., a substrate to be exposed and/or a substrate table supporting the substrate.

Alignment measurement arrangement and alignment measurement method


According to some embodiments, a document processing unit may receive information associated with a document to be processed. The document processing unit might comprise, for example, a printer, scanner, copier, facsimile machine, or multi-function device. The document processing unit may then determine a user identifier indicating a user associated with the document to be processed. At least one user preference value associated with the user may then be automatically retrieved, and the document may be processed in accordance with the user preference value.

Different users may operate and/or use a document processing unit, such as a printer or scanner, in different ways. For example, a first user might generally prefer to print documents on 8½ by 11 inch paper while a second user generally prefers A4 paper. As another example, a particular user might frequently scan documents and send copies of each document to a particular distribution list (e.g., a predetermined set of email addresses).
Typically, a user will control operation of a document processing unit by entering and/selecting options via a control panel (e.g., a keypad or touchscreen). For example, a user might select a paper size, print quality, etc. via a keypad on a printer or scanner. Similarly, a user might enter email addresses, select electronic folders, etc., via the control panel to indicate where documents should be stored. Such an approach, however, can be a time consuming process that a user might need to repeat many times. Moreover, the approach may be error prone and could lead to, for example, a copy of a document being transmitted to an unintended recipient.
Thus, it can be difficult to efficiently and accurately control the operation of a document processing unit, especially when a relatively large number of people, documents, and/or document processing units are involved.

Automated user preferences for a document processing unit


A mobile communication device, such as a mobile phone, which comprises a processor which is configured to process requests for authorisation of use of a credential, such as a credit card, and the processor causes the device to emit a signal, such as an audible intermittent tone, the characteristics of which are indicative of the deemed importance of a particular use of the credential.

Where a user interface device, such as a mobile phone, has been configured to receive and process requests for authorisation of use of a credential, such as a credit card, it has been realised that it would be desirable to alert the person who controls the mobile phone to the pending transaction by means of a signal which is emitted by the phone which is indicative of the monetary value, say, of the transaction. The control of the provision of authorisation for use of the credential is thus facilitated.
The term credential is used herein to denote any means which provides prima facie authority for entitlement to do something, for example a credit or debit card paying for goods or a pass card or PIN for entering a particular region of a building.

Abstract: Advantageously the owner of the device is alerted to the deemed importance of a use of a credential. For example, an intermittent tone of characteristic frequency is emitted by a mobile phone in relation to the monetary value of a transaction using a credit card.

Hewlett-Packard Development Company, L.P.


A multiobjective evolutionary algorithm unit feeds a set of parameters of an individual to a search history storage device in a fitness estimating unit and to an optimization target. The optimization target outputs a set of sampled values of fitnesses on the basis of the set of parameters of the individual. The search history storage device stores the set of parameters of the individual and a set of sampled values as a search history. The fitness estimating module computes a set of estimated values of true fitnesses on the basis of the search history stored in the search history storage device for output to the multiobjective evolutionary algorithm unit. The multiobjective evolutionary algorithm unit determines a Pareto-optimal population in accordance with a genetic algorithm on the basis of a plurality of sets of estimated values.

1. Field of the Invention
The present invention relates to a multiobjective optimization apparatus, a multiobjective optimization method, and a multiobjective optimization program which optimizes the parameters of a target to be optimized.
2. Description of the Background Art
Conventionally, problem classes referred to as multiobjective optimization problems exist. As an example, a multiobjective optimization problem with two objective functions arises when one wishes to minimize the cost of a product while maximizing its performance. In this case, the cost and the performance are the two objective functions. In general, a trade-off relationship exists whereby reducing the cost degrades the performance while improving the performance increases the cost. Accordingly, the solution to such a multiobjective optimization problem cannot be a single solution.
FIG. 36 is a diagram showing the application of the multiobjective optimization problem to the optimization of an engine. In the application of the multiobjective optimization problem to the optimization of fuel consumption and torque of an engine, the fuel consumption and torque are the two objective functions f1, f2. In this case, the values of the objective functions f1, f2 are optimized by adjusting parameters such as the amount of injected fuel, ignition timing, etc.
A solution A is superior to a solution B in fuel consumption, while being inferior to the solution B in torque. Since in this manner, the fuel consumption and engine torque have a trade-off relationship, a plurality of optimal solutions can be found. A user can select a solution from the plurality of optimal solutions that is suited to a particular purpose. For example, for an engine used in an automatic motorcycle suited for sport operation, the solution A is selected, and for an engine used in an automatic motorcycle suited for long touring, the solution B is selected.
The multiobjective optimization problem, in general, is defined as a problem of minimizing the values of M objective functions with respect to N parameters within the range of constraints for each parameter. Maximization of objective function values is converted to a problem of minimizing the objective function values by applying a minus sign to the objective functions.
Such a multiobjective optimization problem typically does not have a single optimal solution but has a population of optimal solutions which are defined as the concept referred to as Pareto-optimal solutions. Note that a Pareto-optimal solution is one in which an improvement in one objective function value requires a degradation of another, which is defined as follows (refer to Document 1, for example):
Definition 1
Given two solutions x1, x2εF for p objective functions fk (k=1, ·. . . , p), x1 is said to dominate x2 if fk(x1)<fk(x2) (∀k=1, . . . , p) ^ fk(x1)<fk(x2) (∃k=1, . . . , p), where F is a population of solutions.
Definition 2
A solution x0 is an optimal solution if x0 dominates all the other solutions xεF.
Definition 3
A solution x0 is a Pareto-optimal solution (or non-inferior solution) if there does not exist any solutions xεF that dominate x0.
Determining a population of Pareto-optimal solutions means to determine a population of optimal solutions for a tradeoff relationship between objective functions.
FIG. 37 is a diagram for use in illustrating Pareto-optimal solutions, showing an example of two objective functions f1, f2. The value of the objective function f1 for the solution a, f1 (a), is smaller than the value of the objective function f2 for the solution b, f1 (b), while the value of the objective function f2 for the solution a, f2(a), is smaller than the value of the objective function f2 for the solution b, f2(b). The solution a therefore dominates the solution b.
Similarly, the solution a dominates the solutions c, d. There does not exist any solutions that dominate the solution a. Also, solutions that dominate the solutions e, f do not exist. This makes the solutions a, e, f the Pareto-optimal solutions.
Note that the solution g is a weak Pareto-optimal solution. A weak Pareto-optimal solution is one that is not dominated by Pareto-optimal solutions with respect to only one objective function. Such a weak Pareto-optimal solution is not a reasonable one, and does not essentially have to be determined.
A number of solutions have been proposed for multiobjective optimization problems, among which are Multiobjective Evolutionary Algorithms (MOEAs) that have recently attracted attention. The most important feature of this method is using a multiple point search in an evolutionary algorithm to determine a population of Pareto-optimal solutions at a time. The population of Pareto-optimal solutions obtained is used, e.g., for decision making in determining a solution among them that is suited to a particular purpose, or for making determinations from the shape of the population of Pareto-optimal solutions (i.e., Pareto-boundary).
Numerous studies are being conducted on the application of genetic algorithms (GAs) as evolutionary algorithms to multiobjective optimization problems. A genetic algorithm is a computing technique that imitates the adaptive evolution in biology. In genetic algorithms, candidate solutions are referred to as individuals, objective functions are referred to as fitness functions, and fitness function values are referred to as fitnesses.
The genetic algorithm is an algorithm suggested by J. Holland, and involves obtaining hints from the processes observed in natural evolution such as selection, crossover, or mutation of chromosomes. Taking design variables as genes, a population of individuals at the initial design is randomly generated, and the fitnesses of each individual are evaluated. A parent is selected such that an individual of better fitnesses is more likely to be selected as the parent. Then, offspring is produced by means of crossover (shuffling of genes) and mutation (random alteration of genes). Generation is iterated by further evaluations, selections, crossovers, and mutations to search for optimal solutions.
More specifically, Fonseca et al. proposed MOGA (Multiple Objective Genetic Algorithm: e.g., refer to Document 1), Deb et al. proposed NSGA-II (Non-Dominated Sorting Genetic Algorithm-II: e.g., refer to Document 2), and Zitzler et al. proposed SPEA2 (Strength Pareto Evolutionary Algorithm 2: e.g., refer to Document 3), to cite examples. NSGA-II and SPEA2, in particular, are known as very useful multiobjective evolutionary algorithms.
Actual applications of multiobjective evolutionary algorithms include problems of determining the wing shape for a supersonic transport, optimization of parameters of a vehicle or engine, etc.
In order to optimize fitness functions having uncertainty, MFEGA (Memory-based Fitness Estimation Genetic Algorithm) was also proposed by Sano, Kita, et al., which allows estimation of true fitnesses using search history (e.g., refer to Document 4). The MEFGA includes storing the sampled data of fitnesses for the previously obtained individuals as a search history, and estimating true fitnesses by reference to the search history. Regarding problems with uncertainty, the MFEGA is reported to have a better search performance than the usual genetic algorithms and methods which require sampling the fitnesses of an identical individual a number of times.
However, the genetic algorithms suggested in Document 1, Document 2 and Document 3 are all applied to a simulation which always results in the same solution, as in the case of a benchmark problem or an ideal model which does not contain probability factors. None of the cases has reported the application of the above-mentioned genetic algorithms to a problem with individuals having noisy fitnesses, as in a real system or a simulation containing probability factors, i.e., a problem having uncertainty. This may be explained by the following two reasons.
For one thing, because a target to be optimized contains noise, the fitnesses of individuals obtained from the optimization target vary for each evaluation, which prevents a satisfactory evolution. That is, individuals that should originally provide good fitnesses are eliminated because the fitnesses are degraded by noise. Meanwhile, individuals that should provide poor fitnesses survive because the fitnesses are improved by noise. Such phenomena prevent normal evolution of the individuals.
For another, the shape of a resulting population of Pareto-optimal solutions is unclear. That is, because of the noisy fitnesses obtained, a Pareto-boundary is not formed when the fitnesses are plotted on the plane of fitness function space, for example, in a two-objective optimization problem. This makes the conventional genetic algorithms difficult for use in decision making or making determinations.
Examples of real systems and simulations containing probability factors that require multiobjective optimization include the optimization of signal switching rules using a traffic volume simulator and the optimization of control parameters of a motor. The purpose of the optimization of signal switching rules is to prevent a traffic jam on two highways by successfully switching the signals at an intersection of and near these highways. The purpose of the optimization of control parameters of a motor is to achieve both the increased responsiveness in the motor and decreased overshoot.
However, for the traffic volume simulator, the velocity and number of passing vehicles are randomly given, and for the motor, measurement errors may be made by sensors, and therefore, computation of fitnesses using the identical individuals (i.e., the rules and the control parameters) results in fitnesses that vary each time. This causes the above-described two problems.
Such problems with uncertainty present serious difficulties not only in multiobjective optimization, but also in single objective optimization. In evolutionary algorithms, several methods for statistically coping with noise are proposed. The most common one involves sampling individuals a number of times, by which with the number of sampling times being n, the noise variance can be decreased to n−0.5. The method, however, increases the evaluation time to a factor of n, which makes it undesirable for use in a time-consuming real system or large-scale simulation.
The MFEGA suggested in Document 4 exhibits good search performance for single objective optimization problems, but fails to provide sufficient studies on applications for multiobjective optimization problems.
(Document 1) C. M. Fonseca, P. J. Fleming: Genetic Algorithms for Multiobjective Optimization: Formulation, Discussion and Generalization; Proceedings of the 5th International Conference on Genetic Algorithms, pp. 416-423 (1993).
(Document 2) K. Deb, S. Agrawal, A. Pratab, and T. Meyarivan: A Fast Elitist Non-Dominated Sorting Genetic Algorithm for Multi-Objective Optimization: NSGA-II, KanGAL Report 20001, Indian Institute of Technology, Kanpur, India (2000).
(Document 3) E. Zitzler, M. Laumanns, L. Thiele: SPEA2: Improving the Performance of the Strength Pareto Evolutionary Algorithm, Technical Report 103, Computer Engineering and Communication Networks Lab (TIK), Swiss Federal Institute of Technology (ETH) Zurich (2001).
(Document 4) Sano, Kita: Optimization of Noisy Fitness Functions by Means of Genetic Algorithms Using History of Search With Test of Estimation; The Transactions of the Institute of Electrical Engineers of Japan, Vol. 122-C, No. 6, pp. 1001-1008 (2002).
(Document 5) K. Ikeda, H. Kita, and S. Kobayashi: Failure of Pareto-Based MOEAs, Does Non-Dominated Really Mean Near to Optimal?; Congress on Evolutionary Computation, pp. 957-962 (2001).
(Document 6) M. D. Berg, et al.: Computational. Geometry: Algorithms and Applications, Springer-Verlag (1997).
(Document 7) Hiroshi Imai, Keiko Imai: Computer Science, Jouhou Sugaku Kouza 12 (Lecture on Information Mathematics No. 12), Kyoritsu Publishing (1994).
(Document 8) E. Zitzler, K. Deb, L. Thiele: Comparison of Multiobjective Evolutionary Algorithms: Empirical Results, Evolutionary Computation 8(2), pp. 173-195 (2000).

Multiobjective optimization apparatus, multiobjective optimization method and multiobjective optimization program


A system and method for performing functional decomposition of a software design to generate a computer-executable FSM and a graphical representation of the design in a decomposition diagram stored in a program database with source code, test code, and other program data. The method includes searching for pre-existing software modules that meet program design requirements. Modules needing work are displayed on Gantt or PERT charts as tasks, and may be annotated with start dates, and completion dates. Percent complete of the design is automatically generated and updated, and may be displayed on the charts. The decomposition is automatically used to introduce error detection states into the FSM for recognizing invalid states and saving checkpoints, and for recognizing and repairing both race conditions and deadlock conditions in the design.

Traditional models for functional decomposition of algorithms are vague in their definition of lower decomposition levels. In the Yourdon structured model, control transformations decompose into state transition diagrams which represent the real-time aspects of the system. Although control transformations were used by Yourdon, Ward and Millor, and Batley and Pirbhai to define real-time control transformation events, their definition of control transformation does not include any of the following types of software statements: goto, if-then-else, switch loops, and subroutine calls.
If the transformations decompose from the highest to the lower levels, but the complexity is not constrained by the developer as the functionality decomposes, as in the McCabe model, the amount of control is unconstrained, and it is not clear when the decomposition should end. Furthermore, since the unconstrained decomposition does not inherently simplify the design, it does not actually meet the criteria of mathematical functional decomposition.
To eliminate the above-noted shortcomings of previous decomposition methods, a simple graph, created in accordance with the multiprocessor functional decomposition (MPfd) model described herein, is constrained to a single control structure per decomposition level and exposes all transitions, preparing the graph for translation into a finite state machine (FSM).
Traditionally, FSMs have been used to create compilers and have also been used in sequential circuit design. Being able to use FSMs in general software design and thus in general programming offers huge benefits for general programming including increased software clarity and the ability better combine computer software with computer hardware.
Management of projects, as done in most software development companies today, is divorced from the software design process. The most common project management tools are the Gantt and PERT (Program Evaluation and Review Technique) charts. Microsoft Corporation has shown that a Gantt chart can be converted into a PERT chart and vice versa. These charts typically show tasks, time durations for each task, task dependencies, and starting dates for each task. The various tasks and their associated attributes are currently manually entered and manually maintained because current project management tools are general tools which are separate from software design.

This patent is subject to a terminal disclaimer.

Automated latency management and cross-communication exchange conversion


Multi-Class Orthogonal Frequency-Division Multiple Access (OFDMA) scheduling may be provided. A plurality of network devices may be assigned a transmission window for channel access. The plurality of network devices may include a first number of client devices and a second number of client devices. A first signal may be sent to the first number of network devices. The first signal may enable the first number of network devices to the channel access in a first portion of the transmission window. An amount of data to be exchanged by each of the second number of network devices may be determined. Based on the determined amount of data to be exchanged, a schedule may be determined for the channel access for each of the second number of network devices in a second portion of the transmission window. A second signal may be sent to the second number of network devices based on the determined schedule. The second signal may enable the second number of network devices to the channel access in the second portion of the transmission window.

Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, etc. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Presence of a large number of user devices with an access point results in competition among the user devices for available resources. In order to address the issue of increasing bandwidth requirements that are demanded for wireless communication systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs.

Multi-class orthogonal frequency-division multiple access (OFDMA) scheduling


Optically active polymers that are composed of monomer residues derived from chiral pre-polymerized monomers, which maintain the chirality of the pre-polymerized monomers upon polymerization are disclosed. These polymers can be composed of monomer residues that are derived from readily available chiral monomers and can be designed to have pre-determined characteristics such as chirality, biodegradability and functionality. Uses of these polymers as therapeutically active agents, and/or as carriers of therapeutically active agents, for delivering the active agents to a targeted bodily site and/or for a sustained release of the active agent, are further disclosed. Also disclosed are processed of preparing the polymers, compositions and medical devices containing the polymers, and conjugates of these polymers and various agents.

The present invention relates to novel polymers and, more particularly, to biodegradable polymers which have a pre-determined chirality, to processes of preparing such biodegradable polymers, to heterostereoselective complexes, conjugates and compositions containing same and to uses thereof.
Biodegradable polymers are polymeric materials that undergo chemical, metabolic (by biological processes such as hydrolysis or enzymatic digestion) and/or mechanical breakdown, in a biological environment (e.g., within a body of a living organism, in the presence of microorganisms, and/or in a biological medium). The biodegradability of such polymeric materials renders them highly suitable for constructing environmental-friendly products, and for use in a myriad of medical applications.
Biodegradable polymeric materials have therefore been used for many years in diverse fields, including, for example, agriculture, fishing materials, sanitation, and articles for everyday life (e.g., masks, wet tissues (wipes), underwear, towels, handkerchiefs, kitchen towels and diapers). Medical applications that utilize biodegradable polymers include, for example, orthopedic surgery, including fixation of fractures, bone replacement, cartilage repair, meniscal repair, and fixation of ligament; absorbable devices such as screws, pins, plugs, and plates for orthopedic, oral, and craniofacial surgery, as well as absorbable sutures; scaffolds for tissue engineering; and as drug carriers. The use of biodegradable drug carriers is the most effective route for delivering a drug, since it enables a sustained systemic release of the drug while circumventing the undesired residual impact of the carrier.
Since non-toxicity is an inherent prerequisite for biodegradable polymers that are designed for medical applications, the starting materials, the final product and the optional breakdown products of such biodegradable polymers should be non-toxic and benign. Breakdown products should preferably be also small, water-soluble molecules.
The total degradation time of biodegradable polymers can vary from several days to several years, depending mainly on the chemical structure of the polymer chains, and physical properties such density, surface area and size of the polymer.
When used in medical applications, the biodegradable polymer of choice for the intended use is selected according to its properties. Thus, for example, semi-crystalline polymers (e.g., poly(L-lactic acid)) are typically used in medical devices that require good mechanical properties such as sutures, devices for orthopedic and cardiovascular surgery, and stents. Amorphous polymers, on the other hand (e.g., poly(DL-lactic-co glycolic acid)), are attractive in drug delivery applications, where it is important to have homogenous dispersion of the active species within the polymeric matrix.
The degradation rate of biodegradable polymers is determined by various factors such as the initial molecular weight, the exposed surface area, and the polymer's degree of crystallinity, the quantitative ratio of the monomers, in the case of co-polymers, the chirality of the polymer (racemic mixture versus pure enantiomeric or diastereomeric form), the presence of additives or impurities, the mechanism of degradation (e.g., enzymatic cleavage versus hydrolysis), the implantation site (e.g., subcutaneous tissue versus bone), the actual stress the polymer is subjected to, and even the age of the host subject.
Biodegradability is typically accomplished by synthesizing or using polymers that have hydrolytically unstable linkages in the backbone. Chemical hydrolysis of the hydrolytically unstable backbone is the prevailing mechanism for the polymer's degradation. Biodegradable polymers can be either natural or synthetic. Synthetic polymers commonly used in medical applications include, for example, polyethylene glycol, polyvinyl alcohol, and poly(hydroxypropylmetacrylamide). In addition, natural polymers are also used in medical applications. For instance, dextran, hydroxyethylstarch, albumin and partially hydrolyzed proteins find use in various applications ranging from plasma substitute, to radiopharmaceutical to parenteral nutrition.
In general, synthetic polymers may offer greater advantages than natural materials in that they can be tailored to give a wider range of properties and more predictable lot-to-lot uniformity than can materials from natural sources. Synthetic polymers also represent a more reliable source of raw materials, one free from concerns of infection or immunogenicity.
Methods of preparing polymeric materials are well known in the art. However, synthetic methods that successfully lead to the preparation of polymeric materials that exhibit adequate biodegradability, biocompatibility, hydrophilicity and minimal toxicity for medical use are scarce. The restricted number and variety of biopolymers currently available attest to this.
The presently used biodegradable polymers for medical applications can be classified by their chemical structure as follows:
Polysaccharides, such as starch, cellulose, chitine, chitosan, and alginic acid;
Polypeptides of natural origin, such as gelatin;
Polymers having carbon backbones, such as polyvinyl alcohol and polyvinyl acetate; and
Polymers having a hydrolyzable backbone, such as polyesters, polycaprolactones, polyamides, polyurethanes, polyanhydrides and poly(amide-enamines).
Some commonly used biodegradable polymers are co-polymers, which are composed of various combinations and variations of hydrolysable polymers.
One of the most appealing groups of biodegradable polymers is the family of polyesters, which are characterized by a —O—R—C(═O)— repeating unit, in which the ester bonds are easily hydrolyzed to hydroxy carboxylic acid monomers when placed in aqueous medium.
Polyesters can be synthesized by polycondensation of diols and dicarboxylic acids, by self-polycondensation of hydroxy carboxylic acids, or by ring opening polymerization (ROP) of cyclic esters (lactones), in bulk or in solution.
Polycondensation can be applicable for a variety of combination of monomers, but generally requires high temperature and long reaction time to obtain high molecular weight polymers. In addition, the chain length of the obtained polymers cannot be controlled. If higher molecular weight polymers are needed, the initially obtained polymers can be further cross-linked, by using, for example, diisocianates, bis(amino-ethers), phosgene, phosphate and anhydrides. The most useful monomers for polycondensation are lactic, glycolic, hydroxybutyric and hydroxycaproic acids, polymers of which are known for their long history of safety.
Ring-opening polymerization can be performed only with a limited number of monomers, but can be carried out under milder reaction conditions and produces high molecular weight polymers in short time, as compared to polycondensation polymerization. Furthermore, recent progress in catalysts and initiators for living polymerization has enabled obtaining polyesters of controlled chain length.
A particularly advantageous subfamily of polyesters includes the poly hydroxyalkanoates (PHAs). PHAs are naturally produced by numerous microorganisms as energy reserve materials in the presence of excess carbon source when an essential nutrient, such as nitrogen or phosphorus, is available only in limiting concentrations. PHAs also form a part of depsipeptides, bio-oligomers ubiquitous in nature, which are composed of hydroxy and amino acids linked by amide and ester bonds. Depsipeptides have recently shown to exhibit high therapeutic potential as anticancer, anti-viral, antibacterial, antifungal, anti-clotting, anti-antherogenic and anti-inflammatory agents [Villar-Garea and Esteller, Int. J. Cancer:2004:112:171-178; Sparidans et al., Biomed. Chromatogr. 2004:18: 16-20; and Mayer and Gustafson, Int. J. Cancer: 2003:105, 291-299]. Depsipeptides are regarded, together with amino acids, as components in the natural chiral pool.
PHAs completely degrade into water and carbon dioxide under aerobic conditions, and into methane under anaerobic conditions by a variety of soil, sea, lake and sewage microorganisms. PHAs exhibit a wide variety of mechanical properties, from hard crystalline to elastic, depending on the nature of the monomer units. For example, MCL-PHAs (medium chain length: 6-10) are semi-crystalline elastomers with low melting point, low tensile strength and high elongation to break, and can be used as biodegradable rubber after cross linking. Some PHAs possess properties of thermoplastics.
Poly(3-hydroxybutyrate) (PHB), the most studied PHA, has a molecular weight in the range of 10-3,000 kDa with a polydispersity of about 2, when produced from wild-type bacteria. Its glass transition temperature is near 180° C., and the densities of crystalline and amorphous PHB are 1.26 and 1.18 g/cm3, respectively. Its mechanical properties (e.g., Young's modulus and tensile strength) are close to that of polypropylene though its extension to break is markedly lower than that of polypropylene.
Thus, PHAs offer an attractive alternative to commonly used synthetic biodegradable polymers.
A general structure of PHAs is presented in Formula I below, where the asterisks denote chiral centers (asymmetric carbons, when R differs from hydrogen):

Exemplary PHAs include poly(3-hydroxypropionate)(R=methyl), poly(3-hydroxybutyrate)(R=ethyl), poly(3-hydroxyvalerate)(R=propyl), poly(3-hydroxyhexanoate)(R=butyl), poly(3-hydroxyoxtanoate)(R=pentyl) and poly(3-hydroxydodecanoate)(R=nonyl).
Additional general features of PHAs characterization and biodegradation are described, for example, in Vert and Garreau [Clin Mater 1992; 10:3-8]; Seebach and Fritz [International Journal of Biological Macromolecules 1999:25:217-236]; Brandi et al. [Adv Biochem Eng Biotechnol 1990; 41:77-93]; Bonthrone et al. [FEMS Microbiol Rev 1992; 10:269-78]; and Mergaert et al. [FEMS Microbiol Rev 1992; 10:317-22].
Biodegradable polymers that have one or more stereogenic center(s) (namely, optically active polymers), offer advantageous features when used as carriers for drug delivery. Many biologically active molecules are optically active (chiral), and usually the biological activity can vary greatly depending on the optical purity of the molecule. Much research activity has been focused on the development of technologies allowing access to pure enantiomers. When serving as carriers of chiral (optically active) drugs, biodegradable polymers that have a pre-determined chirality can serve for forming a hetero-stereo complexes with a chiral drug, thus serving as an optically active delivery system.
Hetero-stereo complexation is a new concept in the interaction between complementary optically active polymeric chains which can be utilized for the delivery of, for example, peptides, proteins and other optically active macromolecules. Unlike common delivery systems where the drug powder is physically entrapped in a polymer matrix and the peptide is released by diffusion through the matrix, stereocomplexes form a stereospecific interaction between the optically active drug and the complementary polymer chain. The drug release under physiological conditions is by cleavage of the polymer chain, which reduces the interactions with the drug.
Recently, it has been shown that optically active polylactic acid (PLA)-based polymers form stable hetero-stereo complexes with various peptides. Slager and Domb reported heterocomplexation between D-PLA and L-configured peptides such as the luteinizing hormone-releasing hormone (LHRH) [Eur. J. Pharm. Biopharm. (2004) δ 461-469; Macromolecules (2003), 36, 2999-3000] leuproide (an LHRH nonapeptides analogue) [Biomacromolecules (2003), 4, 1308-1315], vapreotide a cyclic octapeptide somatostatin) analogue) [Advanced Drug Delivery Reviews 55 (2003) 549-583], insulin [Biomaterials 23 (2002) 4389-4396], lysozyme and somastatin [Journal of Controlled Release (2005) 107 (3) 474-483].
Furthermore, biodegradable polymers that have a pre-determined chirality can be used to enhance the permeation of the drug delivery system through various membranes. Thus, it has been reported, for example, that enantioselective transdermal permeation was observed with some chiral excipients, indicating that and t using chiral polymers as drug carriers may assure that only the active drug penetrates the skin [Reddy et al., Crit. Rev Ther Drug Carrier Syst. 2000; 17(4):285-325)].
In addition, when biodegradable polymers are designed to biodegrade via enzymatic cleavage, the chirality of the polymer or of portions thereof, namely, L or D, plays a crucial role in the degradation process. Thus, portions of a biodegradable polymer which has a D chirality would be stable to enzymatic degradation, whereby portions of polymer which have L chirality would be readily susceptible to enzymatic degradation.
The beneficial effect of chiral biodegradable polymers, and the other advantages associated with polyesters in general, and PHAs in particular, have prompt many researchers to study the properties and synthesis of α-hydroxy carboxylic acids, the building blocks of these polymers.
There are numerous examples where the hydroxyl group at the α-position provides an internal control element, facilitating stereoselective transformations of a prochiral functional group. It has been found that chiral α-hydroxy carboxylic esters, acids and their salts, offer versatile synthetic intermediates for the synthesis of polyesters that contain additional chiral centers.
Although α-amino carboxylic acids (amino acids, AA) are considered relatively cheap reagents, there are only a few examples of traditional chemical methods that directly produce α-hydroxy-carboxylic acids or their salts from α-amino carboxylic acids or their salts. The main obstacles of such a transformation generally result from the use of water-sensitive reagents and low temperatures on extremely polar compounds at a relatively unreactive and stereochemically sensitive center.
Thus, for example, α-hydroxy carboxylic acids can be prepared using α-keto carboxylic acids or esters as starting materials. This methodology, however, is limited due to the non-chirality, high cost and limited availability of the starting materials. The chirality of the final product is often induced by a stoichiometric amount of a chiral auxiliary, requiring several synthetic steps and/or a bulky and costly chiral reductant.
Enantioselective reduction of enones can be achieved using a catalytic amount of a chiral oxazaborolidine [Coney, et. al. Tet. Lett., 1990, 31,611]. However, a sequence of four chemical conversions are required in order to transform the initially formed chiral alcohol to a α-hydroxy ester with obvious cost and yield implications.
Enzymatic methods that produce chiral α-hydroxy-carboxylic acids have also been suggested. These methods utilize α-keto carboxylic esters or acids as precursors and involve catalysis by purified or isolated reductases [see, for example, U.S. Pat. Nos. 5,098,841; 4,326,031; and 5,686,275).
WO 02/33110 discloses processes that utilize α-amino carboxylic acids or their salts as starting materials for the efficient and inexpensive production of α-hydroxy acids. This process involves the use of two enzymes: amino acid deaminases (AAD) along with lactate dehydrogenases (LAD). This patent application, however, fails to teach the use of hydroxy carboxylic acid for preparing biodegradable polyesters, and hence further fails to teach the provision of biodegradable polyesters while utilizing amino acids as the starting material.
The use of proteinaceous materials for producing biodegradable polymers has been recently disclosed in WO 04/50732. According to the teachings of WO 04/50732, primary amine and/or amide groups of a proteinaceous substrate are replaced by hydroxyl and/or carboxyl groups, respectively, and the resulting substrate is subjected to polymerization. The hydroxyl and carboxyl groups are introduced to the substrate by reaction with nitrous acid or nitrous oxides. The hydroxyl and carboxyl groups are introduced to the substrate by replacing amines and amides either at the N-terminus of the substrate or at a side chain thereof. Polymerization is thereafter effected via formation of esters bonds between hydroxyl and carboxyl groups. In preferred embodiments of this patent application, amine or amide groups at the side chain of peptides are replaced by hydroxyl or carboxyl groups and polycondensation is effected between two compatible side chains of two polymers, to thereby generate polyamides that are interlinked therebetween via polyester bonds. The conditions under which the modification of the proteinaceous material and the polymerization thereof are effected are relatively harsh and are not directed at maintaining the chirality of the proteinaceous substrate.
Furthermore, the functionality of the proteinaceous material is affected by utilizing its side chain for polymerization. WO 04/50732 therefore fails to teach processes of polymerizing proteinaceous materials while maintaining the original chirality and functionality of the pre-polymerized material upon polymerization.
Thus, there is a widely recognized need for, and it would be highly advantageous to have, novel processes of producing polymers, in particular polyhydroxyalkanoates, in which the chirality and functionality (e.g., side chain structure) of the pre-polymerized monomers forming the polymer, is maintained.

Biodegradable polymers having a pre-determined chirality

Yissum Research Development Company of the Hebrew University of Jerusalem