The invention is directed to an amplifier circuit with adjustable gain which includes a plurality of parallel-connected differential amplifiers connected to a common cascode stage. An actuation unit is used to activate the differential amplifiers independently of one another on the basis of an applied control signal. The principle described makes it possible to dispense with inductances in the differential amplifier and hence to reduce unwanted crosstalk, while having a high linearity. Secondly, the amplifier's drawn current matches the respective output power which can be tapped off. Overall, the principle described is particularly suitable for use in UMTS mobile radios.

In radio-frequency engineering, "RF power amplifiers" are normally used on the output side in the transmission path. In the case of third-generation mobile radios, for example, which are designed for UMTS (Universal Mobile Telecommunications Standard), "W-CDMA" (Wide-Band Code Division Multiple Access) signals with a bandwidth of two megahertz need to be amplified over an exponential characteristic curve on a carrier-frequency level of approximately 2 Ghz. An exponential transfer characteristic of this type is typical of variable gain amplifiers (VGAs) and can be plotted as a straight line in a semilogarithmic representation. In this case, the output power in decibels is normally plotted over the control voltage of the amplifier in volts.
Adjustable radio-frequency amplifiers of this type are subject to great demands in terms of current drawn, efficiency, linearity, noise and chip area requirement. The latter demand results in problems with crosstalk, and in radio-frequency engineering, particularly in unwanted break-through of carrier frequencies, self-mixing effects etc. The current drawn normally needs to be small because such mobile radios are normally powered from batteries or storage batteries.
Power amplifiers in the radio-frequency range are normally in the form of inductively degenerated differential amplifiers which are designed using bipolar circuitry and have a connected current cascode.
A differential amplifier of this type is specified, by way of example, in the document P. R. Gray, R. G. Meyer "Analysis and Design of Analog Integrated Circuits", John Wiley and Sons, 1993, pages 377 to 378 and 511 to 513, cf. FIG. 5–10 therein, for example. This differential amplifier can be used to advantage, particularly with respect to the high gain, the high cut-off frequencies, low inherent noise and good linearity on account of the inductive degeneration. In this case, the output of the cascode stage is normally in the form of an open collector output in integrated transmission circuits. As a load resistor, a surface acoustic wave filter is normally connected to a power amplifier stage of this type, which represents the nonreactive load thereof. This serves to suppress unwanted signal components. Any adaptive network which may be required at the output of the open collector output is normally connected externally in this case.
The inductive degeneration of the differential amplifier with inductances connected between the common emitter node of the amplifier and the emitter connections of the two differential amplifier transistors brings about the negative current feedback which is wanted, said negative current feedback giving rise to just low inherent noise in the overall system when the quality is high and allowing the transfer function to be linearized.
When amplifying radio-frequency signals, however, the inductance disadvantageously acts as an antenna or transformer, particularly in the GHz range, and thus presents an unavoidable problem as regards the crosstalk of signals through the alternating electromagnetic field on the integrated circuit onto other circuits. A further problem is regulation of the power output from the amplifier. For the gain A, it holds true that A is proportional to the product of gm,red and Rload, where gm,red represents the transconductance of the common-emitter differential amplifier transistors. Rload is the load resistance connected to the open collector output. In this case, the gain of the cascode stage has been assumed to be one. The gradient is essentially determined by the collector current and the value of the emitter degeneration in the relevant radio-frequency range, in line with the following rule:
      g          m      ,      red        ≈      1                  1                  g          m                    +              Z        L              ≈      1                            U          T                          I          C                    +              Z        L            where gm is the gradient, ZL is the complex degeneration resistance, IC is the collector current and UT is the voltage equivalent of thermal energy.
It can be seen that the power output from the amplifier can be controlled only by intervening in the latter's supply of quiescent current, which would disadvantageously shift the amplifier's operating point accordingly. With a relatively large gain range, however, this would bring about unwanted nonlinearities in the differential amplifier.
The document A. B. Grebene "Bipolar and MOS Analog Integrated Circuit Design", John Wiley and Sons 1984, pages 444 to 448, illustrates a developed amplifier with a current shunting principle in the cascode stage. In this case, two cascode stages are connected in parallel (cf. FIG. 8.37 therein, for example) which change over the current signal from the amplifier smoothly from the output to the supply voltage. This is possible if an additional control block is used to shift the bias potentials of the cascode transistors linearly. As a result,
      I    C    =            I      S        ·          exp                    (                              U            BE                                U            T                          )            results in an exponential characteristic curve from the amplifier for regulation which is linear in a semi-logarithmic representation. The most serious drawback of power regulation of this type is provided by the constant current drawn by the power amplifier. A power-saving mode can be provided only by using a not insignificant amount of auxiliary power for the control block. The amplifier itself requires a constant power at every point of the characteristic curve, which significantly reduces the efficiency of the overall circuit when the output power is brought down.

Amplifying circuit with adjustable amplification and transmitter system comprising such an amplifying circuit


A tubular gas guide element for a side curtain airbag for guiding gas coming from a gas generator comprising at least two layers of fabric. With the use of such a gas guide, thrust of the gas inflowing into an airbag can be balanced.

So-called side curtain airbags are known in vehicle technology. These airbags are located in the area of the side roof rail of a motor vehicle and expand in front of the side windows and possibly the B-pillar of a motor vehicle in case of need. Such a curtain airbag by its nature exhibits a relatively large basic area. This large area results in the problem of evenly discharging the gas emerging form a single gas generator into the airbag.
A curtain airbag unit exhibits a large-surface airbag skin and a gas generator for filling of the airbag skin. The airbag skin typically has an upper edge, which is fixed in the area of the roof rail of the motor vehicle, so that the longitudinal direction of the airbag extends along the longitudinal axis of the vehicle. Filing preferably occurs from the upper edge. Two concepts are currently used for this result.
In the first concept, the gas generator is located on one of the two ends of the upper edge (generally the rear end), and a long, thin metal lance forming several outlet openings extends from the gas generator into the inside of the airbag skin, said metal lance distributes the gas over the length of the airbag skin.
In a second concept, the airbag skin exhibits an accommodation area for the gas generator in the area of the upper edge between the front and the rear end, which extends into the inside of the airbag skin or which is at least connected with the inside. For this purpose the accommodation area can be L-shaped, for example.
If, according to the first concept, gas guide elements in the form of metal tubes are used, at least two disadvantages result: on the one hand such tubes are relatively thin in relation to their length, which makes them very susceptible to damage and therefore there are considerable transport costs involved during transport from the manufacturer to the site of final assembly. Furthermore, the assembly unit of gas generator and gas guide element is not thrust neutral and therefore constitutes a risk.
Therefore, the suggestion has already been made to manufacture gas guide elements of fabric. A gas guide element made of fabric is described, for example in JP 2002-187519 A.
One problem in the use of tubular gas guide elements made of fabric is that if cylindrical gas generators which are thrust neutral are used, the hot gas first strikes directly against the inner walls of the fabric tube. This can lead to failure of the material and therefore to faulty function of the airbag.
In the second concept, the following problem occurs: generally, cylindrical gas generators are used which are formed so as to be thrust neutral for reasons of safety. This means that the gas outlet openings are arranged so as to be rotationally symmetrical on a part of the jacket surface of the gas generator. Without additional measures there would be the problem that airbag fabric would be directly subjected to the stream of the hot gases and would possibly be damaged. Therefore deflectors are used which protect the airbag fabric against the outflowing gas.
Such a deflector, implemented in the form of a U-shaped metal sheet, is known from patent WO 02/079008 A1. Furthermore, a gas guide element made of fabric which is sewn into the airbag skin is known from this publication.
A disadvantage of such a deflector element is that the airbag unit, when finally assembled and complete, does not behave in a manner which is thrust neutral. Namely, if the airbag becomes overheated due to a thrust imbalance, the airbag skin consisting of plastic fabric material may become burned.

Tubular gas guide element, gas generation and feed unit and curtain airbag unit


The present invention relates to a system and apparatus comprising automated analysis and feedback on soft tissue imaging quality, including analysis and feedback in real time and in conformance with key parameters and metrics which affect the quality of an image. The system is arranged to implement a method wherein method for providing a qualitative and/or quantitative assessment of an image including several steps. The steps include using an imaging apparatus to obtain at least one soft tissue image of a patient and at least one test object image; deriving a soft tissue image parameter and statistical data from image data from the soft tissue image. The system and method are characterised by employing a metric for the assessment in comparison to the parameter and statistical data, wherein the metric is obtained from the soft tissue image data, data obtained from the at least one test object image, and data from the imaging apparatus.

Mammography is a specialised medical imaging procedure which uses low-dose x-ray to image the breast. Mammography has three main purposes: screening, diagnosis and intervention. Screening mammography entails imaging an asymptomatic population to detect breast cancers, ideally at an early stage; diagnostic mammography entails imaging for the purpose of diagnosing an abnormality discovered by physical exam or screening mammography; and intervention entails performing subcutaneous procedures under x-ray guidance.
For most women, screening mammography is performed on an outpatient basis and comprises a generally routine procedure whereby each breast is positioned between compression plates and an image receptor, the breast is compressed usually by a paddle to a preselected compression pressure, and images are taken from two angles—craniocaudal (CC) and medio-lateral oblique (MLO). These steps are generally repeated for both breasts. In some women, body habitus will require the acquisition of additional images to ensure a complete exam that includes all breast tissue.
Furthermore, image quality is complex, with variability at each stage of an imaging chain of steps in a method for obtaining an image of soft tissue, and interplay between each element of the imaging chain; including physical characteristics of the imaging device, image acquisition technique factors, intrinsic subject characteristics, the skill of the operator, the effect of any processing applied to the image, the method of image display, and the psychometric factors involved in image visualization and interpretation for diagnostic decision-making.
The accuracy and therefore usefulness of each image depends on the correct positioning of the breast: the absence of any confounding materials such as other body parts; and adequate compression pressure. Compression of the breast is required in order to: immobilise the breast to avoid image unsharpness; flatten the breast to minimise tissue overlap for better visualization; minimize the thickness of tissue and thereby the amount of radiation required; and reduce x-ray scatter which may lead to degradation of image quality. The breast must not be over-compressed as it may cause discomfort to the subject. As soon as each image is acquired, the breast is released from compression. As a result, and because the C-arm of the mammography x-ray machine must be rotated to adequately position the patient for the next view, the breast must be manipulated and repositioned each time.
Optimally the resulting image has sufficient spatial resolution (detail) to image small structures (including micro-calcifications) and sufficient contrast to make soft tissue masses and other lesions evident.
A patient's anatomy affects positioning: the patient's height, size, weight and shape, patient breast size and shape, breast tissue composition, surface features and other artefacts, abnormal body habitus such as kyphosis, and the degree of discomfort felt and tolerated by each patient. Patient cooperation (for example, leaning in to the machine, remaining still and holding the breath as directed) is important for example to stabilize the patient and avoid image unsharpening due to patient motion.
Ascertaining the quality of an image and thereby which images are most appropriate for screening and diagnostic purposes, relies on the skill of the radiographic technologist, who visually assesses each image after it has been taken. In 'checking' the image, the radiographic technologist might assess whether the image meets internal, or local, regional or national standards and can be deemed 'acceptable'. If an image is not deemed 'acceptable' by the radiographic technologist, s/he may determine that it is necessary to acquire an additional replacement image or a variant of the original image. Once all necessary views have been acquired and 'accepted', the images are sent to the clinician for a screening or diagnostic reading. Preferably, in preparation for the reading, other prior mammographic images from the same patient are also sent to the clinical workstations for simultaneous review. The clinician will also benefit from having related images of the breasts from other diagnostic imaging studies, both current and prior, from modalities such as, but not limited to: ultrasound; magnetic resonance imaging (MRI); positron emission mammography (PEM); breast specific gamma imaging (BSGI); and contrast enhanced spectral mammography (CESM).
In 'reading' a collection of images the clinician can correlate physiological features such as general shape and size of the breast, the nipple, skin line and pectoral muscle and distances within; and 'match' features to establish concordance.
Even if the position of the breast appears optimal at image acquisition, many errors cannot be anticipated or overcome even with the skill and experience of a system operator or clinician, and images are routinely rejected and repeated because of unanticipated defects in imaging quality.
For screening and diagnostic purposes, other parameters are also considered, such as the tissue composition of the breast; glandular pattern; historical events such as history of prior benign or malignant disease, prior biopsies or surgeries, trauma, and other characteristics, for example artefacts such as clips, lesions, and matching features. Knowledge of other patient information at the time of mammography image reading may further inform the thresholds a clinician might use for detection of disease when 'reading' the mammogram and related images. One such ancillary piece of patient clinical information is the woman's propensity toward breast cancer, otherwise known as her risk of developing breast cancer.

System and apparatus for clinical decision optimisation


A method and an apparatus for reducing the jitter and end-to-end delay on lines of a packet switching network conveying voice or video digitalized data for one or more connections between a local source and a remote source at a constant bit rate.. The method and apparatus of the invention are for use in a voice or video processor of a voice or video processing server of a network node; the method and the apparatus provide a way of controlling the remote traffic rate from the remote source before accessing the processor without using an external clocking such as the network clock.. The solution proposed by the invention consists in buffering the remote and local traffics to adapt the remote traffic rate to the local traffic rate, which is supposed having a limited jitter, while sequencing of the access of the buffered data to the processor.

Transmitting real-time traffic on full-duplex lines over packet networks is expected to play an important role in future telecommunications. Digital based devices are superseding their classical analogue counterparts in public switched network, increasing the demand for analogue-digital (A/D) conversion, data coding/decoding, echo cancellation and compression/decompression.
The devices involved are typically shared by several sources using time division multiplexing (TDM). Time domain multiplexing of data streams of several source requires exact synchronization of those sources to be performed efficiently.
In a full-duplex voice and/or video communication, need for synchronization is pronounced by having in almost every case a local source and a remote source which communicate. The local source defined as being physically close the data signal processing apparatus provides a signal with low latency or jitter and a constant bit-rate. The signal of the remote source while crossing the network is subject of end to end delay, and comparably large jitter. Depending on the quality of the intermediate network, connection parameters like cell delay variation or burst size can only be approximately guaranteed for the remote source.
An asynchronous process consists in receiving and processing the packets when they arrive in the input packet stream. This method is not a problem when the processor is not loaded. However, when signal processing requires to process the signal transmitted from the remote source and from the local source within the same time slot, synchronization measures to secure this simultaneous process are necessary. The synchronous process may consist in using a timer for re-synchronization: this method requires the access to an external clock such as the network clock. Usage of a timer is applied in the system described in the European Patent EP224626. In an telecommunications access node the port adapters, thanks to the network lines attachments, can re-synchronize the traffic using the clock of the network. However, in a processing server which is a part of the network node with no external network line attachment, it is not simple to retrieve the clock from another part of the node.
In view of the prior art, it is therefore an object of the current invention to provide a method and apparatus for synchronizing a remote and a local source of traffic to be Processed as to minimize overrun and underrun of the processor when there is a difference in the frequency of both sources without using an external clock. As many connections are established on the same lines, it is a further object of the invention to minimize delays when feeding signals of several pairs of local and remote sources (connections) to the shared signal processing device.

Method and apparatus to reduce jitter and end-to-end delay for multimedia data signalling

International Business Machines Corporation


During the processing of a transaction or other distributed computation, a computation management system creates a number of agents to handle various aspects or portions of the computations to be performed. Each agent progresses through a predefined set of state transitions which define the status of the agent at any point in time. The computation management system defines for each agent a set of dependencies, each dependency corresponding to a state transition which will be blocked until a particular state transition occurs in another specified agent. By defining selected combinations of dependencies for each agent, a variety of different interdependencies and cooperating protocols can be implemented. The distributed processing management system can be used both for managing transaction processing and for synchronizing events in other types of distributed computations.

Referring to FIG. 1, the present invention concerns interactions and interdependencies of agents 102-1 through 102-N cooperating in a distributed processing computer system 100. Depending on the operating system used, each agent may be a thread or process, and thus is a unit that executes a computation or program. Some of the agents 102-1 through 102-N may be executing on a single common data processing unit while others are executing at remote sites on other data processing units. More generally, agents can be hosted on different computer systems using different operating systems. For the purposes of the present discussion, it is sufficient to assume that there is a communications path or bus 110 which interconnects all the agents in the system 100.
In a typical system 100, some of the agents will be resource managers, such as a database management server (DBMS), while other agents will be computational units working directly on behalf of the users of the system. For those not familiar with transaction (database) processing, a DBMS is a program which handles all access to a particular database, thereby relieving users of the system from having to deal with such complicated technical problems as efficiently storing data and sharing data with a community of users.
In a transaction processing system such as an airline reservation system, agents will be created dynamically as requests are made at reservation terminals. Each agent is created by portions of the system to handle various aspects of the work associated with any particular query or set of queries or updates being sent by a particular reservation terminal.
The present invention concerns a general methodology for interlinking these agents 102 so as to maintain data consistency and to define and enforce interdependencies between the calculations being performed by various ones of the agents. For instance, one agent 102-1 might generate a query that results in the formation of two child agents 102-2 and 102-3, each of which will handle database operations in different portions of the distributed database. At the time that the two child agents 102-2 and 102-3 are created, the present invention defines exactly how these agents are interdependent, and sets up the necessary data structures to denote those interdependencies, as will be explained in more detail below.
Each agent 102 represents a particular computation as a finite state machine which progresses through a sequence of internal states. Complex computations are mapped by their agents into simpler sets of states suitable for synchronization with other computations. A typical sequence of state transitions for an agent is shown in FIG. 2. Definitions of the states 121-127 for the agent shown in FIG. 2 are listed in Table 1.
TABLE 1 ______________________________________ REF STATE NAME DESCRIPTION ______________________________________ 120 Active Performing a computation 121 Finishing Computation is complete and waiting for one or more finish pre-conditions to be satisfied 122 Finished Computation is complete and all finish pre-conditions have been satisfied 123 Preparing Check on whether agent is able to commit the transaction 124 Prepared Agent is prepared to commit or abort 125 Committing Agent is unconditionally committed. Results of computation become visible. 126 Aborting Rollback objects affected by computation so as to leave everything as it was before computation began 127 Forgotten Computation completed or aborted and purged from system ______________________________________
In a typical transaction processing system, the process running in an Agent can be aborted due to an internal error condition at any time until the processes is prepared. Typical internal error conditions which might cause a process to abort include a "divide by zero", an attempt to execute an illegal instruction due to a programming error, an unauthorized attempt to access privileged system resources, or the unavailability of a resource needed to complete the computation. Once the agent has prepared, this means that the agent guarantees that it can save the results of its computation in a permanent fashion if the distributed transaction commits, and that it can rollback the results of the transaction so as to leave everything as it was before the transaction began should the distributed transaction fail to commit.
The present invention provides a very general and flexible system and method for making state transitions in each agent dependent on the status of other agents cooperating in the distributed process.

System for distributed computation processing includes dynamic assignment of predicates to define interdependencies


An active solar reflector, preferably mounted within a transparent dome, tracks the sun from sunrise to sunset to reflect impinging solar radiation into a room or other space to be lighted. The reflector includes a plurality of angled mirrors mounted one behind the other and of progressively increasing heights to intercept and reflect as large a flat plate area of solar radiation as possible. The mirrors are mounted upon a support rotatable about an axis to track the sun and to have the mirrors continuously reflect the impinging solar radiation.

1. Field of the Invention
The present invention relates to solar reflectors and, more particularly, to an active solar reflector having angled mirrors of progressively increasing heights rotatably mounted to track the sun and continuously reflect as much impinging solar radiation as possible during the early and late hours of the day.
2. Description of Related Art
Interior rooms and other spaces within buildings have been naturally lighted through use of transparent or translucent roof mounted skylights or domes. These domes permit solar radiation to be transmitted directly through a shaft into the space of interest. During a time period after sunrise and during a similar period before sunset, the angle of inclination of the sun is relatively low and little light shines through the dome into the space to be lighted. At noon, the sun is at its highest point and solar radiation through the dome is at a maximum. As a result, the amount of light contributing to lighting of the space of interest is represented by a bell-shaped curve having an ordinate in time and an abscissa in light radiation. Such extensive differences of natural light during the day continually alters the color perception within the space of interest to a significant degree. To maintain an adequate level of light necessary, artificial light must be used during a significant part of the day and may be left on all day due to inattention or laziness resulting in unnecessary consumption of energy and added expense.


A continuous cardiac output monitor a general-purpose monitoring console with local display and communication facilities, and a module removably interfacing with the console to configure the latter for performing continuous cardiac output monitoring. The module includes a switch-mode high efficiency power amplifier for providing electrical heating power at a selected voltage, frequency, and wave form to a heating element of a continuous cardiac output monitoring catheter, which catheter at a distal end portion thereof is immersed in the blood flow of a patient. The catheter effects a temperature transient in the patient's blood flow by the controlled application of electrical resistance heating utilizing electrical power from the power amplifier, and this temperature transient is sensed and used to derive a value for the patient's cardiac output.

1. Field of the Invention
The present invention relates to power amplifiers or electrical power supplies. More particularly, the present invention is in the field of power amplifiers for supplying electrical power at a chosen frequency or frequencies and at a selected and variable voltage level or levels. Still more particularly, the present invention is in the field of regulated electronic power amplifiers or supplies which supply a selected level of electrical power at a controlled frequency and variably controlled voltage to an electrical load. With particularity to the application environment of such power amplifiers or power supplies, the present invention relates to such a power amplifier which is particularly configured and constructed for use in the medical environment to supply resistive heating power to a continuous cardiac output monitoring catheter. Thus, the present invention also is in the field of apparatus and method for monitoring the cardiac output of a human patient.
2. Related Technology
Conventionally, cardiac output monitoring for patients experiencing a cardiac crisis, such as may occur over a period of time following a coronary occlusion, is to periodically inject a quantity (or bolus) of chilled saline solution into the patient's circulatory system at a selected location. A temperature monitoring catheter is used at another selected location to sense the temperature-versus-time relationship of the blood flow so that a value of cardiac output can be derived. This technique is known as thermodilution, and provides a good signal to noise ratio of the pulmonary blood flow as it is cooled by the chilled saline solution as compared to the normal temperature of blood flow in the pulmonary artery prior to and after the injection of the bolus of saline. A relationship known as the Stewart-Hamilton equation is used to derive the cardiac output value.
Unfortunately, this conventional technique is dependent on the skill of the person who performs the saline injection. That is, the rate and uniformity over time with which the bolus of saline solution is injected can influence the accuracy of the result. Consequently, a number of such tests over a period of time are used to determine an average value of cardiac output. Detection of a trend or long-term change (over a period of hours, for example) in cardiac output is very difficult with this conventional technique. Also, the injection of chilled saline may have the disadvantage for some patients of adding a relatively large quantity of water to the blood stream. This water must be removed by the patient's kidneys.
Another conventional cardiac output monitoring technique utilizes a catheter instilled through the right atrium and right ventricle of the heart, and from the heart into the pulmonary artery. A resistance heating element externally carried by this catheter is used to intermittently slightly heat the pulmonary blood flow from the heart as this blood flows toward the patient's lungs. Downstream of the heating element, the catheter carries a temperature sensing element. The temperature-versus-time relationship of the sensed blood flow can similarly be used to derive a value for cardiac output. This technique has the advantage of providing substantially continuous monitoring of cardiac output. However, the signal-to-noise ratio of the heated blood temperature in comparison to the normal body temperature of blood flow existing prior to and after an interval of heating is very low. This must be the case because the blood cannot be heated excessively or damage will result to formed blood cells. Consequently, techniques have been developed to heat the pulmonary blood flow on a pseudo-random basis, so that the resulting temperature variations can be detected and distinguished from the otherwise normal slight variations in temperature of the pulmonary blood flow.
For reasons of patient safety and avoidance of electromagnetic interference with or effect upon other monitoring and treatment apparatus which may also be in the medical environment around a patient, a frequency of 100 KHz has been recognized as the most desirable for use in powering the resistance heating element of the monitoring catheter. With this fixed frequency of applied power for the resistance heating element of the catheter, a variable voltage level is used to control the power level of energy liberated at the heating element into the patient's pulmonary blood flow. This control on the level of heating energy liberated into the patient's blood flow must be carefully controlled because the actual rate of blood flow circulation for the patient may be decreased or impaired, so that overheating must be avoided.
In addition to the above, it is increasingly recognized that the modern medical environment is restrictively complex. That is, the complexity of medical monitoring and treatment apparatus which must be used with some seriously ill or injured patients restricts access to the patient and presents the risk of error or malfunction of the apparatus. Additionally, hospitals and clinics face a significant burden in maintenance, service, storage, and logistical planning of the availability of this complex and expensive medical apparatus. As a result, an increasingly popular trend in the hospital, clinical, and portable medical treatment environments (fire departments, emergency medical teams, and military portable field hospitals, for example) is to use a general purpose monitoring device which can be electronically configured to serve a variety of monitoring functions.
Configuration of the monitoring device is accomplished by simply plugging into the console of the general purpose monitoring device one or more modules containing the circuitry and stored information necessary to accomplish particular monitoring functions. In the hospital and clinical environment, for example, this technology has the advantage that the general purpose monitors may be installed in or left in the patient rooms and in the emergency or critical care areas, for example. These monitors need not be moved about the hospital or clinic. The monitors are simply configured to perform various monitoring functions as are necessitated by the condition of the particular patient by plugging the appropriate modules into the monitor consoles. Only the modules need to be moved about the hospital or clinic. The modules themselves are comparatively small, light and inexpensive. Storage of the modules when they are not in use requires far less space than does the conventional monitoring equipment. Also, movement of the necessary configuration modules about the hospital or clinic environment does not present nearly the burden for hospital staff as does the movements of conventional monitors.
That is, conventional monitors are relatively large, heavy, and expensive pieces of equipment, which are generally mounted on wheeled carts. Each time a monitor is moved from one location to another within a hospital, for example, there is a certain risk that it will be damaged in the process of movement. Also, the physical movement of the monitor requires the services of a relatively strong member of the hospital service personnel, for example, to move the wheeled cart and monitor onto and off of hospital elevators. On the other hand, the configuration modules of modular type monitoring equipment are small enough to be carried by hand from one location to another. In fact, several of these modules can be carried at a time by one person if necessary. A single wheeled cart of a size comparable to one conventional monitor can carry several to several dozen of the configuration modules for a modular monitoring system.
With respect to the conventional continuous cardiac output monitors, the monitor includes a linear electronic power amplifier capable of supplying a variable power level and fixed frequency of electrical alternating current power output, and which provides electrical heating power to the resistance heating element of the continuous cardiac output monitoring catheter. This conventional linear power amplifier is physically too large to be accommodated within the envelope of a monitoring module of the newer modular-type of monitoring apparatus. Also, the conventional power amplifier is of a power efficiency so low that although only about fifteen watts of power is dissipated into the patient's blood flow on an intermittent basis, about thirty to forty-five watts, or more, of power is liberated as heat into the console of the conventional continuous cardiac output monitor. That is, the efficiency of these conventional linear power amplifiers may be as low as 25 percent. Were this level of heat to be liberated within a monitoring module, assuming that the conventional linear power amplifier could somehow be physically fitted into the module, the conventional plastic casing of the module could be warped or melted by the resulting high temperatures.

Electrical power amplifier for continuous cardiac output monitoring


The invention provides a choke system with hydraulic circuits which provide choke valve positioning that can be varied by the use of incremental steps. The incremental movement action in either the opening or closing direction is accomplished through the use of one of the two hydraulic slave cylinders which can either add or subtract a fixed volume of hydraulic fluid from the choke actuator. A series of check valves provides direction for flow in the hydraulic lines, locking of the choke actuator, and re-filling of the slave cylinders during operation. The system eliminates excessive lines or solenoid valves and avoids the need for mechanical locking mechanisms. Preferred embodiments include a “fast close” system which, instead of running through a series of steps to close the valve, provides valve control in a fast close line to move the choke actuator to the full closed position from anywhere in the travel over a shorter period of time than through normal stepping operation.

A choke valve is a throttling device. It is commonly used as part of an oil or gas field wellhead. It functions to reduce the pressure of the fluid flowing through the valve internals. Choke valves are placed on the production "tree" of an oil or gas wellhead assembly to control the flow of produced fluid from a reservoir into the production flow line. They are used on wellheads located on land and offshore, as well as on wellheads located beneath the surface of the ocean.
In general, chokes involve:                a valve body having an axial bore, a body inlet (typically referred to as a side outlet) and a body outlet (typically referred to as an end outlet);        a "flow trim" mounted in the bore between inlet and outlet, for throttling the flow moving through the body; and        means for actuating the flow trim, said means closing the end of the bore remote from the outlet.
There are four main types of flow trim commonly used in commercial chokes. Each flow trim involves a port-defining member, a movable member for throttling the port, and seal means for implementing a total shut-off. These four types of flow trim can be characterized as follows:                (1) a needle-and-seat flow trim comprising a tapered annular seat fixed in the valve body and a movable tapered internal plug for throttling and sealing in conjunction with the seat surface;        (2) a cage-with-internal-plug flow trim, comprising a tubular, cylindrical cage, fixed in the valve body and having ports in its side wall, and a plug movable axially through the bore of the cage to open or close the ports. Shut-off is generally accomplished with a taper on the leading edge of the plug, which seats on a taper carried by the cage or body downstream of the ports;        (3) a multiple-port-disc flow trim, having a fixed ported disc mounted in the valve body and a rotatable ported disc, contiguous therewith, that can be turned to cause the two sets of ports to move into or out of register, for throttling and shut-off; and        (4) a cage-with-external-sleeve flow trim, comprising a tubular cylindrical cage having ports in its side wall and a hollow cylindrical sleeve that slides axially over the cage to open and close the ports. The shut-off is accomplished with the leading edge of the sleeve contacting an annular seat carried by the valve body or cage.
In each of the above, the flow trim is positioned within the choke valve at the intersection of the choke valve's inlet and outlet. In most of the valves, the flow trim includes a stationary tubular cylinder referred to as a "cage", positioned transverse to the inlet and having its bore axially aligned with the outlet. The cage has restrictive flow ports extending through its sidewall. Fluid enters the cage from the choke valve inlet, passes through the ports and changes direction to leave the cage bore through the valve outlet.
Such a flow trim also includes a tubular throttling sleeve that slides over the cage. The sleeve acts to reduce or increase the area of the ports. An actuator, such as a threaded stem assembly, is provided to bias the sleeve back and forth along the cage. The rate that fluid passes through the flow trim is dependent on the relative position of the sleeve on the cage and the amount of port area that is revealed by the sleeve.
Maintenance on the deep subsea wellhead assemblies cannot be performed manually. An unmanned, remotely operated vehicle, referred to as an "ROV", is used to approach the wellhead and carry out maintenance functions. To aid in servicing subsea choke valves, choke valves have their internal components, including the flow trim, assembled into a modular sub-assembly. The sub-assembly is referred to as an "insert assembly" and is inserted into the choke valve body and clamped into position.
When the flow trim becomes worn beyond its useful service life due to erosion and corrosion caused by particles and corrosive agents in the produced substances, an ROV is used to approach the choke valve, unclamp the insert assembly from the choke valve body and attach a cable to the insert assembly so that it may be raised to the surface for replacement or repair. The ROV then installs a new insert assembly and clamps it into position. This procedure eliminates the need to raise the whole wellhead assembly to the surface to service a worn choke valve.
In order to efficiently produce a reservoir, it is necessary to monitor the flow rate of the production fluid. This is done to ensure that damage to the formation does not occur and to ensure that well production is maximized. This process has been, historically, accomplished through the installation of pressure and temperature transmitters into the flow lines upstream and downstream of the choke valve. The sensor information is then sent to a remote location for monitoring, so that a choke valve controller can remotely bias the flow trim to affect the desired flow rate. The controller sends electrical signals to means, associated with the choke valve, for adjusting the flow trim.
Choke valves common to oil and gas field use are generally described in U.S. Pat. No. 4,540,022, issued Sep. 10, 1985, to Cove and U.S. Pat. No. 5,431,188, issued Jul. 11, 1995 to Cove. A subsea choke valve is described in U.S. Pat. No. 6,782,949, issued Aug. 31, 2004. All of these patents are assigned to Master Flo Valve Inc., the owner of this application.
Control valves, such as choke valves, are often equipped with a means to provide position control. In the most fundamental form, manual operation by a lever or hand wheel is used. To provide remote control of a valve's position a variety of actuators, including hydraulic actuators, can be used.
U.S. Patent Application published Nov. 4, 2004 as US 2004/02116884 and naming Bodine et al. as inventors, describes known hydraulic actuator control systems for subsea chokes as follows:
In offshore oil and gas production, it is often common for more than one well to be produced through a single flow line. In a typical installation, the products from each individual well flow are combined into a common flow line, which then carries the products to the surface or combines those products with the products of other flow lines. The difficulty in managing a multiple well completion produced through a single flow line is that not all of the wells may be producing at the same pressure conditions or include the same flow constituents (liquids and gases).
For example, if one individual well is producing at a lower pressure than the pressure maintained in the flow line, fluid can back flow from the flow line into that well. Not only is the loss of production fluids undesirable, but the pressure changes and reverse flow conditions within that well may damage the well and/or reservoir. Similarly, if one well is producing at a pressure above the flow line pressure, that well may produce at an undesirable flow rate and pressure, again with the potential to damage other wells and/or the reservoir. Thus, the management of flow rates and pressures is of critical importance in maximizing the production of hydrocarbons from the reservoir.
In one prior art subsea production system, control signals and a hydraulic fluid supply are transmitted along an umbilical from a topside control system to a subsea control module which supplies hydraulic fluid to actuators in the subsea trees, manifolds, valves, choke and other functions. As control valves within the control module receive signals to open or close the choke, the control valves actuate to control the flow of hydraulic fluid to the choke actuator through either hydraulic lines opening or closing. A common choke actuator is a hydraulic stepping actuator, which, depending on the style of actuator and choke being used, may take 100 to 200 steps to close, although systems requiring a smaller, or larger, number of steps are possible. Each step involves the actuator receiving a pulse of hydraulic pressure, which moves the actuator, and then a release of that pressure, which allows a spring to return the actuator to its initial position. In typical systems, where the SCM (subsea control module) is located proximate (e.g., within about 30-feet) to the choke/actuator, about one second is required for the pressure pulse to travel from the control valve in SCM to the actuator and two seconds are required for the spring to return the actuator to its initial position. Thus, with a total of three seconds per step and a total of up to 200 or more steps required to fully actuate the choke, the time required to fully close or open the choke is considerable. The risk of equipment failure is also increased due to the components being actuated hundreds, thousands, or even millions, of times.
In another typical prior art subsea production system, control signals and a hydraulic fluid supply are transmitted along an umbilical from a topside control system directly to a subsea choke, bypassing the subsea control module on an electro hydraulic control system. Operation of a direct hydraulic control system would also be as described above, since no subsea control module is required, and a direct electric (control) system would operate similarly, minus any hydraulic control lines. The choke is opened and also closed via hydraulic signals transmitted through dedicated umbilical lines. Hydraulic signals from the surface control the flow of hydraulic fluid to the choke actuator through either hydraulic opening and closing lines. The common choke actuator is a hydraulic stepping actuator which, depending on the style of actuator and choke being used, may take 100–200 steps to close. Each step involves the actuator receiving a pulse of hydraulic pressure, which moves the actuator, and then a release of that pressure, which allows a spring to return the actuator to its initial position. In typical systems, the time required for the pressure pulse to travel from the surface to the actuator is directly related to the offset distance (umbilical length from surface to choke), water depth and actuating pressure, which can be minutes per step for long offsets. Also, an additional amount of time is required for the spring to return the actuator to its initial position. The time to actuate each step can run into minutes, thus, with a total of up to 200 steps required to fully actuate the choke, the time required to fully close or open the choke is considerable.
In yet a third typical prior art subsea production system, electrical power and a hydraulic fluid supply are transmitted along an umbilical from a topside control system directly to a subsea choke actuator system, bypassing the subsea control module on an electro hydraulic control system. Operation of a direct hydraulic control system would also be as described above, since no subsea control module is required, and a direct electric (control) system would operate similarly, minus any hydraulic control lines. A hydraulic fluid supply is stored local to the choke, such as in accumulator. The choke is opened and also closed via electrical signals transmitted through dedicated umbilical conductors to actuate the open and close functions. The electrical signals are received by a directional control valve that regulates hydraulic flow to the open and close functions of choke actuator. For this instance, hydraulic fluid is supplied to the local choke accumulators, which are refilled by the hydraulic supply along an umbilical. The common choke actuator is a hydraulic stepping actuator which, depending on the style of actuator and choke being used, may take 100 to 200 steps to close. Each step involves the actuator receiving an electrical power pulse, followed by a pulse of hydraulic pressure, which moves the actuator, and then a release of the electrical power that releases the hydraulic pressure, which allows a spring to return the actuator to its initial position. In typical systems, roughly one second is required for the electrical power pulse to travel from the surface to the choke, and then for the pressure pulse to travel from the local choke accumulator to the actuator and roughly two seconds are required for the spring to return the actuator to its initial position. Thus, with a total of three to four seconds per step and a total of up to 200 steps required to fully actuate the choke, the time required to fully close or open the choke is considerable. The power requirements for this type of system are considerable, while the umbilical must have electrical conductors (one for open, one for close) for each choke.
U.S. Pat. No. 6,782,952 issued Aug. 31, 2004, discloses a hydraulic stepping valve actuator for moving the sliding sleeve of a downhole well valve. The system relies on a mechanical locking system to restrain the sleeve at each incremental position. As well, the system does not provide a fast close fail system, which is needed in a production well.
There remains a need in the art for systems and methods for increasing the responsiveness and speed of choke control systems, especially subsea systems.

Linear hydraulic stepping actuator with fast close capabilities


A method for MAC address management is provided. A MAC address is provided, and capacities of a first column and a second column corresponding to a first index in a MAC table are checked. If the first column and the second column are filled, capacities of a third column and a fourth column corresponding to a second index in the MAC table are checked. If one of the third and fourth columns is empty, the MAC address is written thereto. The second index is successive to the first index. The MAC table further comprises a plurality of time stamp columns, recording idle time of each MAC address.

1. Column of the Invention
The invention relates to computer networks, and in particular, to media access control (MAC) address management.
2. Description of the Related Art
FIG. 1a shows a conventional MAC table. Conventionally, a typical router or switch establishes a MAC table in the memory to keep track of MAC addresses in streamed packets. A MAC table comprises a plurality of columns, such as first column 100, second column 102, third column 104 and fourth column 106, each capable of storing one MAC address. Addresses of every four columns also serve as indices for rapid access. For example, Index1 is an index for the columns 100, 102, 104 and 106.
FIG. 1b is a flowchart of a method for conventional MAC address management. If 2048 columns are provided in a memory block, 512 indices are therefore available each corresponding to four columns. In step S102, when a packet is received, the MAC address thereof is calculated according to a hash algorithm to obtain a corresponding index. Alternatively, the index may be directly obtained from the last 9 bits of the MAC address. In step S104, the MAC table is consulted to determine whether the MAC address is already stored in the corresponding four columns. If not, a learning procedure is processed in step S108 to update the MAC table with the MAC address. Conventionally, there exists an expiration time limit in every MAC address if there is no access to a MAC address for a period of time, and the MAC table eliminates the expired MAC address automatically. If the MAC address is already stored in a corresponding one of the four columns, the access time of the MAC address is updated to keep it from expiration in step S106.
FIG. 2a is a flowchart of a learning procedure for conventional MAC address. The procedure includes the following steps. In step S202, the corresponding four columns of the MAC table are checked according to the index generated by the MAC address. In step S204, it is individually checked whether the capacities of one of the four columns are available for the MAC address. If one of the columns is available, the MAC address is stored thereto in step S206. If all four columns are filled, one of the columns is overwritten in step S208. The principle for overwrite is that selecting a column to be overwritten if the expiration time limit of a column is almost reached. Alternatively, the four columns may be overwritten in turn or at random.
FIG. 2b shows a conventional MAC table. Index1, Index2 and Index3 each correspond to four columns. Among the columns with Index1, column 200 stores a MAC address (marked as learned), and the other three are empty. Columns 208, 210, 212 and 214 of Index2 are filled with MAC addresses (learned). When a new MAC address corresponding to Index2 is provided, the column 208 is overwritten. Therefore, the four columns corresponding to Index3 are empty.
Using indices to access the MAC addresses is convenient; however, the utilization of memory is not efficient. For example, overwrite is required if all columns with Index2 are filled with MAC addresses and one more MAC address of Index2 is provided. In fact, there are still a lot of free memory spaces such as columns with Index3. An enhancement is desirable to efficiently use all available memory resources.


Provided is a testbed for conducting an experiment on a substance in a cryogenic liquid state in a microgravity environment. Such a testbed includes a frame with rectangular nominal dimensions, and a source section supported by the frame for supplying the substance to be evaluated in the cryogenic liquid form. An experiment supported by the frame includes an experiment vessel in fluid communication with the storage tank to receive and condense the substance into the cryogenic liquid state. A sensor senses a property of the cryogenic liquid in the experiment vessel as part of the experiment, and a bus section includes a controller configured to control delivery of the substance to the experiment vessel, and receives property data indicative of the property sensed by the sensor for subsequent evaluation on Earth.

1. Field of the Invention
This application relates generally to a method and apparatus for evaluating fluid behavior as part of a scientific experiment and, more specifically, to a testbed and testing method of evaluating the behavior of a cryogenic liquid in a microgravity environment. The testbed can be a miniaturized (e.g. CubeSat) satellite testbed that can be launched into low-Earth orbit as a secondary payload aboard a rocket or other vehicle capable of leaving Earth's atmosphere, and that carries an experiment for evaluating cryogenic-liquid behavior in microgravity.
2. Description of Related Art
Cryogenic liquids are vital to the continued exploration and exploitation of space, particularly for missions beyond Earth's orbit. For example, liquid cryogens are used as rocket fuel for propulsion of spacecraft. Certain cryogens, e.g. liquid oxygen, are densified forms of atmospheric gases suitable for human respiration that may prove invaluable for storage on long space missions, for example a manned mission to Mars. These cryogens must be stored in tanks carried by the spacecraft for use as-needed, e.g. for thrust, maneuvering, course adjustment or breathing.
The behavior of liquid cryogens in storage tanks within the atmosphere and subject to Earth's gravity has been studied and is well understood. But despite the importance cryogens currently play and will continue to play in orbital and beyond-orbital space missions, there is little data concerning the behavior of liquid cryogens in a micro-gravity environment. Such data would be useful to the design and execution of both orbital and long-range spaceflight missions where liquid cryogens are or will be stored onboard a spacecraft for use during the mission.
A key hurdle to studying the behavior of cryogenic liquids in space is cost. A recent estimate to construct and launch a satellite-based testbed to evaluate cryogenic-liquid behavior was $100 to $200 million. To this point, the associated high cost has stood in the way of this important work. There is accordingly a need for an economical and practical satellite testbed for evaluating cryogenic-liquid behavior in a microgravity environment.

Satellite testbed for evaluating cryogenic-liquid behavior in microgravity


A ligating band dispenser for attachment to the distal end of a ligating device having proximal and distal ends with a lumen extending therebetween and being adapted for supporting a plurality of ligating bands includes a support for attachment to the distal end of the ligating device and for carrying the plurality of ligating bands and having a passage communicating with the lumen; and a dispenser including a first displacement element looped about each of the bands in series attached to the support and extending through the passage and lumen whereby proximal motion of the operator element from the proximal end of the ligating device transfers individually the most distal ligating band off the distal end of the support.

It is well known that one can treat various types of lesions including hemorrhoids and esophageal varices by ligation. The object of ligation is to position an elastic cord, or ligating band, around the lesion to stop circulation through the tissue and allow the tissue to die whereupon the body sloughs off the dead tissue. One instrument for facilitating the placement of a single ligating band or set of bands includes, at its distal end, a ligating band dispenser comprising two rigid, concentric tubes. The tubes can slide with respect to each other under the control of a trigger mechanism at the proximal end of the instrument. A rigid endoscope having internal passages forming a suction path and a light path interconnect the trigger mechanism and dispenser. The dispenser inner tube can be loaded with a set of one or more elastic rings or ligating bands. A separate stopper bar attaches to the instrument to prevent premature dispensing. When the instrument is located proximate a lesion, a surgeon removes the stopper bar and applies suction to draw tissue into the hollow passage at the distal end of the dispenser. Pulling on the trigger retracts the inner tube. The larger diameter of the outer tube engages the ligating band so the band cannot displace with the inner tube. As the inner tube is withdrawn from the ligating band, it slides off the inner tube and elastically contracts onto the tissue.
Another instrument includes a ligating band dispenser with an inner tube that moves with respect to an outer tube to dispense a ligating band. This dispenser is oriented at right angles to the rigid endoscope and includes a structure for moving the inner tube of the dispenser in this configuration.
A third similar dispenser approach includes an inner tube that moves axially with respect to an outer tube at the distal end of the instrument. The outer tube attaches axially onto the distal end of the endoscope. An operating mechanism in the form of a pull wire with a weighted handle maintains tension on the inner tube so that it does not displace axially outwardly while the instrument is being positioned. For some applications it is suggested that the endoscope structure be inserted through an overtube to prevent premature dispensing. Suction can be applied to draw tissue into the central aperture of the dispenser formed by the inner tube. Then a surgeon pulls the handle and retracts the inner tube axially past the distal end of the outer tube to force the ligating band of the instrument onto the tissue.
Each of the foregoing instruments dispenses a single ligating band or a single set of ligating bands at a single location. None suggests dispensing ligating bands at discrete locations. These instruments apparently would have to rely on a surgeon's sense of touch in order to displace the inner tube by an incremental distance corresponding to the thickness of a stretched ligating band to deposit a plurality of bands at different sites. That would be very difficult to accomplish.
Indeed, when it was desired to deposit ligating bands at different sites, the common practice was to load and dispense one band and to withdraw the entire instrument from the patient and load a new ligating band onto the inner tube each time. Loading ligating bands onto an instrument requires special tools and can be time consuming, particularly if the special tooling must be available to install each ligating band individually while the instrument is withdrawn. Each of these instruments requires some structure, such as special stoppers or overtubes, for preventing the premature dispensing of the ligating band. Consequently, none of these instruments is readily adaptable for dispensing ligating bands at different sites without withdrawing the instrument after each individual site is ligated.
Another device, a multiple ligating band dispenser for ligating instruments includes interfitted inner and outer structures that support a plurality of ligating bands at axially spaced locations. Retraction of the inner structure dispenses one ligating band. Extension of the inner structure advances the remaining ligating bands distally, axially so the next retraction dispenses another ligating band. This ligating band dispenser overcomes some but not all of the undesirable characteristics of single-band dispensers. For example, prior art single-band dispensers can eject a ligating band inadvertently if, during placement, tissue at the distal end of the dispenser, rather than the physician, moves the distal edge of the movable tube. The multiple band dispenser overcomes this problem by using a spring to bias the movable tube to a distal position. However, the use of the spring increases the force that must be used during the dispensing operation. Also, the distal edge of the movable tube is the most distal part of the dispenser. During placement, this edge engages the lesion to form a vacuum seal thereby allowing the lesion to be withdrawn into the lumen of the endoscope. When the movable tube moves proximally during the dispensing operation, the vacuum seal can break thereby enabling the lesion to pull away from the dispenser.
In one attempt at dispensing a plurality of ligating bands individually and sequentially, a support, coaxially attached to the distal end of an endoscope, carries the plurality of ligating bands at axially spaced positions along an exterior surface. There are two concentric tubes with grooves inside the outer tube. The elastic ligating bands are positioned between the tubes and within the grooves so that rotation of the outer tube by means of a screw mechanism advances all the bands. This allows the bands to be sequentially advanced off the end of the dispenser. In another embodiment there are two concentric tubes, the inner being rigid and the outer being a flexible fabric. The bands are arranged on the outer surface of the fabric tube separated by small protrusions forming grooves on which the bands rest. The distal edge of the fabric is folded over the distal edge of the rigid tube so that it may be pulled proximally inside the rigid tube. A cable is provided to pull the fabric tube inward, causing the bands to be sequentially released from the end of the device. Both advance all the ligating bands simultaneously. Due to the strong elastic force applied by the bands on the housing and the friction between the bands and the housing, moving all bands at the same time requires significant pull force. In addition, moving all the bands simultaneously increases the likelihood of inadvertently firing two or more bands simultaneously.
Another attempt for dispensing a plurality of ligating bands individually and sequentially uses a support, coaxially attached to the distal end of an endoscope, and carries the plurality of ligating bands at axially spaced positions along an exterior surface. One or more displacement filaments are looped around each band; each filament then loops over the distal edge of the dispenser where it is secured. The other end of each filament runs beneath the band, over the distal edge of the dispenser and joins with a pull wire which exits the proximal end of the endoscope. When a physician moves the pull wire a certain distance proximally, the filaments sequentially advance each band off the distal edge of the dispenser, releasing the securing means as the band slides off the distal end of the dispenser. Various means are described to enable a single pull wire to sequentially advance multiple sets of filaments.
This approach overcomes some of the drawbacks of earlier devices. In treating lesions of the esophagus or other difficult to approach structures, it is desirable to have a sufficient number of ligating bands to assure completion of the procedure without the necessity of removal and reinsertion of the endoscope. Although this device can deliver multiple bands, it has some drawbacks. Each band has one or a pair of filaments used for advancing the band over the distal edge of the structure and onto the tissue. A complex attachment harness is used to assure that the series of loops of filaments is displaced sequentially to release only one band at a time from the distal end. Additionally, when the number of bands increases, the assembly labor and manufacturing complexity of assembly of the device becomes significant, and increases considerably with increasing numbers of bands. In addition, the displacement filaments all run though the working channel of the endoscope, and the small diameter of this channel limits the number of filaments. Additionally the filaments may limit the suction and obstruct other functions such as delivery of fluid or other devices through the working channel. The large number of filaments significantly obstructs drawing of tissue into the ligating structure and limits visibility through the end of the device.


Provided is an optical fiber illuminator used for recording and reading high density optical information according to a near field recording (NFR) scheme, a method of fabricating the optical fiber illuminator, and an optical recording head and recording apparatus having the optical fiber illuminator. The optical fiber illuminator includes: an optical fiber having a core upon which light is incident and a clad that surrounds the core, one end of the optical fiber having a mirror formed in an inclined manner; and a lens formed on an outer surface of the optical fiber for focusing light reflected by the mirror. The optical fiber illuminator has an improved optical arrangement for optical illumination and detection, it is easy to manufacture, its optical input is easy to control, and it can be readily provided in an array form. When an array type optical recording and reading apparatus having an optical recording head and multiple aperture probes adopts the optical fiber illuminator, the resulting simple arrangement and compact size enables size reduction of the overall apparatus, a signal to noise ratio is high, and high density optical information can be recorded and reproduced at an extremely high rate.

1. Field of the Invention
The present invention relates to an optical fiber illuminator used for recording and reading high density optical information in a near field recording (NFR) scheme, a method of fabricating the optical fiber illuminator, an optical recording head, and an optical recording head and recording apparatus having the optical fiber illuminator.
2. Discussion of Related Art
In general, optical recording technology that uses focused laser light to record and read information onto/from an optical disk has been the focus of considerable attention as high capacity digital information storage technology.
In conventional technology using a lens optical system, a minimum spot diameter of an optical source is restricted to about half of a wavelength due to a diffraction limit, which limits recording density. Therefore, recently, a near field recording technology using an aperture probe has been widely used to overcome the diffraction limit.
The near field recording technology uses the principle that light passing through a hole (aperture) smaller than a wavelength of laser light propagates in an evanescent wave within a distance similar to the size of the hole. With an aperture probe positioned within a distance of one wavelength of laser light from a recording medium, marks smaller than a wavelength of the laser light can be recorded or read. Therefore, the near field recording device is capable of an extremely high storage density (200 to 400 Gbit/in2) compared to other existing optical recording devices.
Recently, as a near field recording technology using an aperture probe, technologies for recording and reading information at a high speed with the aperture probe formed on a cantilever or a planar slide head have been researched.
U.S. Pat. No. 5,517,280 (May 14, 1996) discloses technology in which a high-speed photolithography process having an optical resolution less than a wavelength is implemented with a number of cantilevers.
A number of cantilevers are caused to vibrate over photoresist, and radiate light through a protruding aperture probe. When the cantilevers vibrate upward and downward, a Van der Waals force is detected through a capacitive plate to control a gap between the aperture probe and the photoresist.
This method exposes photoresist through a number of aperture probes so that multiple nano-scale lithography processes can be performed. However, it is difficult to integrate an optical waveguide into the cantilever through a semiconductor process, and optical transmission efficiency from the optical waveguide into the aperture probe is low, making the method difficult to implement. In addition, the method lacks a specific driving and control technology for manufacturing a large-area scanner.
U.S. Pat. No. 6,466,537 (Oct. 1, 2002) discloses technology in which an aperture is formed on a planar head rather than a probe, and near field light emitted or absorbed from the aperture is measured to read information or control a gap between the head and the media.
The near field light emitted from the aperture is measured to control the gap, so that the gap can be controlled without contacting the probe. A gap between the head and the medium can also be controlled with a flying head used in hard disks. However, with a head arrangement having a signal aperture, this technology is readily adapted to a ROM arrangement for reading a recorded pattern, but it is difficult to adapt to an arrangement for recording information at a high rate.
Korean Patent No. 441,894 (Jul. 16, 2004) discloses a near field optical information recording and reading apparatus using a 1-D array type aperture probe and a micro integrated near field recording head.
Light emitted from an optical fiber comprising an optical illuminator is collected by a micro ball lens, diffracted by a micro mirror, and then incident on the aperture probe. Reflected light is detected with the optical illuminator to read recorded optical information.
However, with the above method, a process of adjusting the micro ball lens and the mirror to collect the incident light on the aperture probe is complicated. In addition, the reflected light is mixed with light scattered around the aperture probe so that it is very difficult to detect only the light reflected from the recording medium. Therefore, a method of reading information through measurement of transmission and so on should be further provided.
As described above, existing technology has many problems concerning an optical arrangement required in optical illumination and detection and a fast and stable optical connection. Consequently, there is an urgent need to improve the existing technology to facilitate its practical use.

Optical fiber illuminator, method of fabricating optical fiber illuminator, and optical recording head and optical recording and reading apparatus having the optical fiber illuminator

Electronics and Telecommunications Research Institute


An amplifying device includes an amplifying element that amplifies a fundamental wave signal, and a short stub that has an electric length one fourth a wavelength of the fundamental wave signal, and is connected to a line on an output side of the amplifying element, the short stub being used as both a bias circuit that supplies a certain bias voltage to the amplifying element and a reflection circuit with respect to a harmonic signal that has a frequency twice a frequency of the fundamental wave signal, wherein the short stub has a pattern width that is larger than a pattern width of the line.

Conventionally, an amplifying device has been used in various kinds of electronic devices. For example, a radio communication device, such as a base station and a user terminal in a mobile communications system, uses an amplifying device that amplifies transmission power of a signal.
There has been known an amplifying device that uses, as illustrated in FIG. 1, a short stub that is a line having an electric length one fourth the wavelength (that is, λ/4) of a fundamental wave signal S1, as a bias circuit that supplies a certain bias voltage to an amplifying element 11. Hereinafter, the short tub is referred to as "λ/4 short stub" in some cases. FIG. 1 is a circuit diagram illustrating one example of the amplifying device in a first related art. The voltage output from a power source Vdd is supplied, as a bias voltage, to an amplifying element 11 via a λ/4 short stub TL1 that is a bias circuit. The fundamental wave signal S1 is amplified by the amplifying element 11, and a signal S2 after being amplified is output from the amplifying element 11. Furthermore, a bypass capacitor C1 is connected between the power source Vdd and a ground in parallel with the bias circuit. Hereinafter, components having the identical functions are given same numerals and their repeated explanations are omitted.
Furthermore, in order to improve amplification efficiency, "harmonic processing" that reflects, on the amplifying element, a harmonic signal out of the signals output from the amplifying element after being amplified may be performed. Hereinafter, the signals output from the amplifying element after being amplified are referred to as "amplified signals" in some cases. The amplification efficiency is, for example, specified by the formula "(output power of amplifying element)/(source power of amplifying element)". When the amplifying element is a field effect transistor (FET), the amplification efficiency is referred to as "drain efficiency" in some cases. There has been known an amplifying device that uses, for example, an open stub that is a line having an electric length one eighth the wavelength (that is, λ/8) of the fundamental wave signal S1, as a reflection circuit that reflects a harmonic signal having a frequency twice the frequency of the fundamental wave signal (that is, "second harmonic signal"). Hereinafter, the open stub is referred to as "λ/8 open stub" in some cases. FIG. 2 is a circuit diagram illustrating one example of an amplifying device in a second related art. As illustrated in FIG. 2, a second harmonic signal S3 out of amplified signals output from the amplifying element 11 is reflected by a λ/8 open stub TL3 that is a reflection circuit, adjusted to a suitable reflection phase by a phase adjustment line TL2, and reaches the amplifying element 11. Because the second harmonic signal S3 is terminated by the λ/8 open stub TL3, an amplified signal S2′ at or after the connection point of the λ/8 open stub TL3 includes a small amount of second harmonic signal S3.
Examples of related-art are described in Japanese Laid-open Patent Publication No. 2011-035761.
Here, the amplifying device using the λ/4 short stub TL1 as a bias circuit (see FIG. 1) and the amplifying device using the λ/8 open stub TL3 as a reflection circuit (see FIG. 2) are combined in a simple manner to obtain an amplifying device illustrated in FIG. 3. FIG. 3 is a circuit diagram illustrating one example of an amplifying device in a third related art. However, in the amplifying device illustrated in FIG. 3, the λ/4 short stub TL1 as a bias circuit and the λ/8 open stub TL3 as a reflection circuit exist independently of each other and hence the arrangement area of the circuit become large.
In terms of the electric length of a line, the λ/4 short stub and the λ/8 open stub exhibit identical characteristics with respect to the second harmonic signal. Therefore, the λ/4 short stub can also serve as the λ/8 open stub. For this reason, as illustrated in FIG. 4, the λ/4 short stub TL1 is used as both the bias circuit of the amplifying element 11 and the reflection circuit with respect to a second harmonic signal, thus eliminating the λ/8 open stub TL3 (see FIG. 3) as a reflection circuit. Consequently, the arrangement area of the circuit in the amplifying device decreases, thus achieving the miniaturization of the amplifying device. FIG. 4 is a circuit diagram illustrating one example of an amplifying device in a fourth related art.
Here, the case in which the λ/4 short stub TL1 used as both the bias circuit and the reflection circuit is mounted on the amplifying device is considered.
First, a circuit model when the line in an amplifying device is an ideal line is illustrated in FIG. 5, and the simulation results of the frequency characteristics of the circuit model illustrated in FIG. 5 are illustrated in FIG. 6. FIG. 5 is a diagram illustrating one example of the circuit model using the ideal line, and FIG. 6 is a diagram illustrating the simulation results of the frequency characteristics of the circuit model using the ideal line. As illustrated in FIG. 5, the frequency of the fundamental wave signal is set to 2.14 GHz. Therefore, the frequency of the second harmonic signal is 4.28 GHz. The line that connects P1 and P2 in FIG. 5 corresponds to the line on the output side of the amplifying element 11 in FIG. 4, and each of the characteristic impedances of a line TLI and a line TLO is set to 50Ω in this case. One end of the λ/4 short stub TL1 whose characteristic impedance is 50Ω is connected to a point located between the line TLI and the line TLO. FIG. 6 illustrates the characteristics between P1 and P2 in FIG. 5. In FIG. 6, the continuous line indicates pass characteristics S21, and the dashed line indicates reflection characteristics S11.
When the line in the amplifying device is an ideal line in FIG. 6, a passing amount (the continuous line) is the maximum and a reflection amount (the dashed line) is the minimum at 2.14 GHz that is the frequency of the fundamental wave signal. On the other hand, a passing amount (the continuous line) is the minimum and a reflection amount (the dashed line) is the maximum at 4.28 GHz that is the frequency of the second harmonic signal. Therefore, as can be understood from FIG. 5 illustrating the circuit model using the ideal line, the λ/4 short stub TL1 is an ideal bias circuit with respect to the fundamental wave signal as well as being an ideal reflection circuit with respect to the second harmonic signal. That is, as can be understood from FIG. 5 illustrating the circuit model using the ideal line, the λ/4 short stub TL1 operates as an ideal element used as both the bias circuit and the reflection circuit.
Next, FIG. 7 illustrates a circuit model when the line in an amplifying device is a microstrip line, and FIG. 8 illustrates the simulation results of the frequency characteristics of the circuit model illustrated in FIG. 7. FIG. 7 is a diagram illustrating one example of a circuit model using the microstrip line, and FIG. 8 is a diagram illustrating the simulation results of the frequency characteristics of the circuit model using the microstrip line.
Here, a circuit actually formed by using the microstrip line is, as illustrated in FIG. 9 and FIG. 10, formed of a dielectric body 51 that constitutes a printed circuit board, a conductor pattern 52 formed on the surface of the dielectric body 51, and a ground (GND) plane 53 formed on a whole area of the back face of the dielectric body 51. FIG. 9 and FIG. 10 are diagrams each illustrating one example of the configuration of the circuit formed by using the microstrip line. FIG. 9 is an overall perspective view, and FIG. 10 is a cross-sectional view. The dielectric body 51 has a dielectric thickness D1. Each conductor pattern 52 has a pattern length L, a pattern width W, and a pattern thickness D2. The conductor pattern 52 is connected to the GND plane 53 via through holes 54 formed in the dielectric body 51.
In FIG. 7 and FIG. 8 as well as FIG. 5 and FIG. 6, the frequency of the fundamental wave signal is set to 2.14 GHz and the frequency of the second harmonic signal is set to 4.28 GHz. In order for a characteristic impedance to be 50Ω in the same manner as the case of FIG. 5, each of the pattern widths of lines MLI and MLO is set to 2.54 mm. Each of the pattern lengths of the lines MLI and MLO is set to 2 mm. Furthermore, in order for the characteristic impedance to be 50Ω in the same manner as the case of FIG. 5, the pattern width of a short stub ML1 is set to 2.54 mm identical with the pattern widths of the lines MLI and MLO. On the other hand, in order for an electric length to be λ/4, the pattern length of the short stub ML1 is set to 24.9 mm. Therefore, each of the pattern widths of connecting lines MT1, MT2, and MT3 located among the lines MLI, MLO, and the λ/4 short stub ML1 is set to 2.54 mm. Furthermore, the dielectric thickness of the dielectric body is set to 0.8 mm, and the relative dielectric constant of the dielectric body is set to 2.
A microstrip line A that connects P1 and P2 in FIG. 7 corresponds to the line on the output side of the amplifying element 11 in FIG. 4 in the same manner as the case of FIG. 5. Hereinafter, the microstrip line A is referred to as "main line A" in some cases. The λ/4 short stub ML1 is connected to the connecting line MT located between the line MLI and the line MLO. FIG. 8 illustrates the characteristics between P1 and P2 in FIG. 7. In FIG. 8, the continuous line indicates pass characteristics S21, and the dashed line indicates reflection characteristics S11.
As can be understood from FIG. 8, when the line in the amplifying device is a microstrip line that is generally used in an actual circuit, a passing amount (the continuous line) is the maximum, and a reflection amount (the dashed line) is the minimum at 2.14 GHz that is the frequency of the fundamental wave signal in the same manner as the case that the line in the amplifying device is an ideal line (see FIG. 6). On the other hand, the passing amount (the continuous line) is the minimum, and the reflection amount (the dashed line) is the maximum at 4.13 GHz, which is different from 4.28 GHz that is the frequency of the second harmonic signal. Therefore, the λ/4 short stub ML1 is an ideal bias circuit with respect to the fundamental wave signal. On the other hand, the λ/4 short stub ML1 is not an ideal reflection circuit with respect to the second harmonic signal. That is, in the circuit model using the microstrip line illustrated in FIG. 7, the reflection amount of the second harmonic signal in the λ/4 short stub used as both the bias circuit and the reflection circuit decreases, thus lowering amplification efficiency compared with the case of the circuit model using the ideal line (see FIG. 5).

Amplifying device and radio communication device


An adjustable shelving system is disclosed for an open-front refrigerated display case having an air-curtain at least partially across a front of the display case and having a shelf configured to hold products to be displayed. A first bracket and a second bracket are coupled to an interior panel of the display case where each bracket includes a first travel stop and a spaced-apart second travel stop. The shelf has pin members that interface with the brackets and engage the travel stops. The pin members engage the first travel stop to retain the shelf in a first position and engage the second travel stop to retain the shelf in a second position having an angle of inclination relative to the first position. A distance from a front edge of the shelf and the air curtain is substantially constant between the first position and the second position.

The present invention relates to an adjustable shelf system. The present invention more specifically relates to an adjustable shelf for use in a refrigerated case for storing and displaying objects such as food products.
It is known to provide for a refrigerated case for storage and presentation of food products (such as meat, etc.). Such known refrigerated cases may include those of a type typically having an open front to permit consumers to reach in and select products from shelves within the case (e.g. "self service" type cases, etc.). Open-front refrigerated cases often have an "air curtain" extending across the front of the case and is made of one or more layers of refrigerated air that flow downwardly from a discharge along a top front portion of the case and is drawn into a return along a lower front portion of the case. The air curtain is intended to minimize "mixing" of surrounding ambient-temperature air with the chilled air within the case and behind the air-curtain.
Such cases often have shelves that are fixed in a generally horizontal orientation. Such cases may also have shelves that are configured to be adjustable between a horizontal and a "sloped" or "inclined" orientation. However, such known adjustable shelves have certain disadvantages. For example, typical horizontal shelves in an open-front refrigerated case often have a front end that is positioned in close proximity to the air curtain. However, such known adjustable shelves typically pivot about a connection point at the rear of the case so that the front end of the shelf rotates inwardly and away from the air curtain as the angle of inclination of the shelf is increased. As the front end of the shelf moves inwardly and away from the air curtain, the air curtain tends to degrade and to draw more external ambient air into the case and tending to decrease performance of the case and to increase product temperatures and energy consumption by the case.
It would be desirable to provide an adjustable shelf for a refrigerated case or the like of a type disclosed in the present Application that includes any one or more of these or other advantageous features:                (1) An adjustable shelf capable of adjustment between a generally horizontal position and a sloped position having an angle of inclination.        (2) An adjustable shelf capable of movement between an angle of inclination of 0 degrees and approximately 30 degrees or more.        (3) An adjustable shelf that is configured to be fixed at one or more angles of inclination.        (4) An adjustable shelf having an adjustment device configured to maintain a front end of the shelf at a generally constant distance from an air curtain as the shelf is adjusted to a variety of angles of inclination.        (5) An adjustable shelf that having an adjustment device that is configured to be quickly and easily adjusted.        (6) An adjustable shelf that maintains a constant area for product presentation at any one of a variety of angles of inclination.        (7) An adjustable shelf that is adapted for use with a case designed for stocking from the front (i.e. front-loading) or from the rear of the case (i.e. rear-loading).

Adjustable shelf system for refrigerated case


An improved multi-purpose caulk finishing tool incorporating a clip (or locking slots) for attaching the tool to a caulking gun and means for storing caps for caulking material. The present invention is held and carried unobtrusively on a conventional caulking gun. Means are also provided for storing caps, for resealing caulking material cartridges, within the caulk finishing tool.

1. Field of the Invention
The invention relates to an improved caulk finishing tool and particularly to a caulk finishing tool which is adapted to attach to a caulking gun for ready availability and which is adapted to provide a cap for resealing cartridges of caulking material.
2. Description of the Background
In building construction and repair, caulking material is commonly used for sealing joints. On the exterior of buildings, joints are made weatherproof by caulking. On the interior of buildings, especially in kitchens and bathrooms, joints are sealed by caulking to prevent water penetration. There are many and varied construction materials including concrete, wood, glass, tile, etc. The joints to be sealed often occur between unlike materials. Consequently, the caulking is available in many different formulations so that an appropriate one can be selected to adhere properly in any given situation. Typically, caulking material is provided in uniformly sized cartridges, having a nozzle at one end and a movable end piece at the other end. The caulking material is applied with a caulking gun, which is adapted to receive and hold the cartridge and has a ratchet driven push rod to force the movable end piece into the cartridge and toward the nozzle. The parallel or "open" frame caulking gun has a pair of rails connecting a front and a rear portion of the caulking gun. The front portion includes a stop for preventing the cartridge of caulking material from sliding when pressure is applied from the rear and the rear portion includes the ratchet drive mechanism.
Alternatively, the cradle or "half-barrel" design caulking gun has a half-cartridge-shaped cradle connecting the front and rear portions. The push rod protrudes from the rear portion of the caulking gun and normally has a right angle bend, at the distal end, to facilitate pulling the rod from the cartridge, after the caulk material has been expended. Some models include a curved ladder hook, so that the caulking gun may be hung from a ladder rung or other support. In either case, the caulking material comes in an airtight sealed cartridge, to preserve its content and prevent premature drying. The cartridge is opened by cutting the nozzle end and puncturing the seal inside the nozzle with a sharp nail or wire. The end of the nozzle may be cut in a variety of ways to produce a bead of caulking material of a desired size. When the ratchet drive mechanism is advanced, the caulking material is delivered through the nozzle.
When caulking, a variety of other tools are commonly used. For example, areas which require caulking often occur at right angle joints and the caulking material is applied first by using the caulking gun to deposit a bead of caulking material along a section of the joint. Afterward, a finishing tool is used to press the bead into the joint and to skim away the excess caulking material. One existing finishing tool is designed with two flanges joined at an oblique angle, which is slightly greater than 90°.
The tool can be pressed into the joint and moved along the bead of caulking material. The tool presses the caulking material into the joint, for a thorough seal, smoothes the surface and removes the excess caulking material, all in one step. In addition, the tool will not disfigure the surfaces adjacent to the joint.
U.S. Pat. No. 3,744,079, to Krause, is an example of a caulk finishing tool of this type, and FIG. 1 herein depicts the '079 tool. Unfortunately, this tool is relatively small, must be carried separately from the caulk gun, and is often lost or misplaced. Moreover, it is common for a workman to arrive at the top of his ladder only to realize that he must descend to retrieve his caulk finishing tool. In addition, once a particular area has been caulked, it is desirable to cap the cartridge to prevent drying of the unused portion. Cartridges of caulking material are generally not provided with means to cap the nozzle, after it has been cut. Plastic caps are available to snap on to the cartridge for sealing the contents, and these typically have a protruding central portion to accommodate the nozzle, and a circular gripping rim. Again, if a workman intends to climb a ladder, caulk a particular area and remain on the ladder to perform some other work, all of the caulking gun and cartridge, the finishing tool, and spare plastic caps must be gathered together and carried up the ladder. For the foregoing reasons, it has long been recognized the of advantage of constructing a multi-purpose tool that can carry the number of separate small tools to a work site and kept within reach during the work. These innovations avoid the necessity of carrying separate tools, misplacing or losing them. This is a great advantage when a workman must climb a ladder to reach the place where caulking material is to be applied. There have been previous caulking guns constructed with an attached rod which can be used to dislodge dried caulking material from the nozzle of the cartridge. However, such rods are not an acceptable substitute for a tool such as shown in the above-described '079 patent. Moreover, no known caulking guns have the ability to dispense or provide a cap for the unspent caulk cartridges.
It would be greatly advantageous to provide an effective caulk finishing tool which removably attached to standard open frame or half-barrel type caulking guns, and which has the dual capacity to dispense or otherwise provide a nozzle cap for the unspent caulk cartridges, all in one convenient readily-accessible tool.