A method for implementing a plurality of backoff counters on a hardware backoff counter for use in implementing a prioritized message transmission network is presented. A message with a smallest backoff time is selected and placed into the hardware backoff counter. When the hardware backoff counter expires, the message is transmitted. Whenever the communications medium becomes busy, the backoff time for every message is updated.

Communications networks use a transmission medium to transmit information in the form of computer data, voice, music, video, etc., from one station to another. The communications medium may be a wired link, a fiber optic link, or a wireless link. The wireless link may include, but is not limited to, radio frequency, infrared, laser light, and microwave. The network may, in fact, use a combination of different communications links.
With the exception of a small number of networks that use dedicated communications links between each station, most information networks use a shared transmission medium to carry the transmitted information. Examples of information networks using a shared transmission medium include: Ethernet, token ring, and wireless Ethernet (IEEE 802.11).
However, by sharing a communications medium between multiple stations, there are situations (extended busy times) that arise when stations are required to wait a significant amount of time before they are able to transmit their data. Additionally, situations (collisions) exist when simultaneous transmissions from different stations occur and result in the mutual destruction of the transmissions. Such situations are undesirable in providing quality of service (QoS) to multimedia data transfers and in making efficient use of scarce spectrum on a wireless medium.
For some applications, such as voice telephony, video tele-conferencing, and other real-time, bi-directional, interactive applications, extended transfer times can severely and rapidly degrade the performance of the applications to a level that is unacceptable. For example, in voice telephony applications, if the delay between one user speaking and another user listening is greater than a few milliseconds, the delay becomes noticeable to the users and the users' satisfaction level for the telephone connection begins to drop.
One way to ensure that applications requiring a low maximum network latency receive the level of service that they require is to implement some form of QoS transfers of data traffic between stations. In many networks with QoS transfers, communications traffic in a network are partitioned into multiple categories and the categories are parameterized or prioritized according to their specific performance requirements. For example, traffic carrying a telephone conversation between two users will be given a higher priority than traffic carrying data for a file transfer between two computers. By creating categories for the traffic, parameterizing and prioritizing the different categories and ensuring that traffic of higher QoS demands or higher priority receives better service, these networks offer and meet performance guarantees.
In wireless local area networks (LANs) specified by the IEEE 802.11 technical standard, each different category of network traffic is required to contend for access to the shared medium. The technical standard specifies a technique using a randomly selected backoff time and a backoff counter to ensure fair access to the shared medium. However, because there are many possible categories of network traffic and the backoff counter requires frequent updates, hardware rather than software has been the preferred implementation method for the backoff counters. This is due to the fact that the frequent updates to the backoff counters places too great of a computational burden on the processor of a network station when the backoff counters implemented in software.
Unfortunately, a maximum number of different traffic categories have not been specified by the IEEE technical standard. Therefore, a particular implementation with a fixed number of hardware backoff counters cannot be assured of having enough backoff counters to support all of the different traffic categories. Additionally, a large number of hardware backoff counters can be expensive in terms of integrated circuit real estate. A need has therefore arisen for a technique that can support a variable number of different traffic categories without placing an undue computational burden on the processor of a network station.

Implementing enhanced distributed coordinating function (EDCF) with a single hardware backoff counter


Techniques for packaging in an optical device and an opto-electrical conversion device are disclosed. According to one aspect of the techniques, the optical device is packaged in a piece of tubing and the opto-electrical conversion device is packaged in a TO-can. While the optical device and the opto-electrical conversion device are coaxially aligned, the tube and the TO-can are integrated by a certain amount of epoxy that is later cured by a UV light or heat. As a result, an integrated optical device is formed and enjoys features of small footprint, better alignment, enhanced impact performance, lower cost in addition to easier manufacturing process and environmental-safe.

1. Field of the Invention
The invention is generally related to the area of optical communications. In particular, the present invention is related to solder-free packaging method for integrated fiber optics device and parts using the method.
2. The Background of Related Art
Generally, an opto-electronic integrated device includes an optical part integrated with an opto-electrical conversion device. The optical part can be a WDM (wavelength division multiplexing) device, an optical collimating or focusing optics, or an optical taping device that splits a small portion of the total input signal to an alternative optical path for monitoring the intensity and wavelength changes of the transmitted signal. The opto-electrical conversion device can be either a photodiode or a laser diode. The optical part and the opto-electrical conversion device are generally sealed in what is commonly referred to as a TO-can. A TO-can packaging of an opto-electrical conversion device includes a metallic case with a transmission window or opening on top for transmitting or receiving optical signals.
An exemplary traditional packaging approach of an integrated device 100 is illustrated in FIG. 1. The integrated device 100 includes various components such as an optical device 103 and an opto-electrical conversion device in a TO-can package 102. The optical device 103 generally includes a plurality of optical subcomponents that are preferably aligned and fixed relative to each other and mounted inside a piece of gold plated tubing by thermal curing epoxy. The individual devices 102 and 103 to be integrated are then aligned and fixed relative to each other. Traditionally, the individual devices 102 and 103 are integrated by soldering the metal tubing directly to the TO-can, if it is gold plated. Alternatively, the TO-can is mounted to a gold-plated metal tube via thermal curing epoxy, and then soldered to the device 104 that had been mounted inside the gold plated metal tubing.
The opto-electronic integrated fiber optics devices packaged by soldering suffers from several issues. In addition to the issues of the thermal instability and manufacturing difficulty, the soldering process is not an environmental-safe process. The industry is calling on all fiber optical communication components to be environmental-safe by 2007, there is a great need for alternative packaging of optics devices that are amenable to small footprint, broad operating wavelength range, enhanced impact performance, lower cost, easier manufacturing process and environmental-safe.

Solder-free packaging for integrated fiber optics device


A computerized data processing system for performing risk analysis of a portfolio, the system including a modeling and calibration unit configured to describe risk factors as random variables, the random variables being related to each other by a correlation matrix; an input unit configured to enter or choose calibration data and to obtain, by using the modeling and calibration unit, values for parameters that describe the degree of freedom for sub-vectors and to obtain values for the correlation matrix for the random variables, to enter or choose at least one risk mapping function, and to enter portfolio data of a portfolio to be analyzed; a simulation unit configured to simulate realization of the risk factors by using the correlation matrix; and an output unit configured to generate output data resulting from the simulation unit in a form of at least one of a risk measure or a price.

The present invention relates to a system and a computer implemented method for performing risk analysis of a portfolio.
The financial services industry, especially the financial risk management departments and the financial security pricing departments of insurance and re-insurance companies and banks, has established in the past tools and means for estimating their financial risk. Such risks can be associated with credit instruments and portfolios of credit instruments, such as bonds and loans. Such risks can also be associated with equity portfolios of various currencies or insurance and reinsurance liabilities.
These tools and means are based on models, based on which simulations are performed to generate possible valuation scenarios. These simulations generally use the Monte Carlo method or other appropriate methods. The models use probability distributions and are calibrated with historical data. Such historical data may be obtained from various sources, such as DataStream™.
These simulations are usually implemented in computer software as part of a financial services system and are run on computer hardware.
The input data for the simulations are risk factors, which are handled as random variables. Such risk factors can be equity indices, foreign exchange rates, interest rates, or insurance loss frequencies and severities. The result or output data of such simulations is at least one risk measure in the form of a numerical quantity or value. Usually, several risk measure values of different types can be obtained.
These risk measure values will be forwarded to an analyst or an actuary or an underwriter, i.e. a human representative of a financial services company. These risk measure values enable him to decide whether or not any actions should be taken to reduce the risk. Such actions can be changes in a credit or equities portfolio, or in a portfolio of insurance and reinsurance liabilities.
The risk measures usually consist of a variety of values, such as the maximum value obtained, the standard deviation of the simulation, a shortfall, usually the 99% shortfall, or a value-at-risk (VAR™). The VAR™ is the greatest possible loss that the company may expect in the portfolio in question with a certain given degree of probability during a certain future period of time. The full distribution itself can be the risk measure as well.
Typically a large number of risk factors have to be considered. Therefore, multidimensional probability distributions have to be used. As the risk measures are often determined at the tail of such distributions, a precise modelling of the tail dependency is important.
Furthermore, the dependency of the risk factors has to be considered. However, when using a linear correlation, the dependency is often not modelled adequately. One known solution to better model dependency is the use of copulas.
These copulas are well known in the state of the art. They are joint distribution functions of random vectors with standard uniform marginal distributions. They provide a way of understanding how marginal distributions of single risks are coupled together to form joint distributions of groups of risks.
Different kinds of copulas are known. Examples of closed form copulas are the Gumbel and the Clayton copula. Examples of implicit copulas, i.e. copulas for which no closed form exists, are the Gaussian copula and the t-copula.
It has become increasingly popular to model vectors of risk factor log returns with so-called meta-t distributions, i.e. distributions with a t-copula and arbitrary marginal distributions. The reason for this is the ability of the t-copula to model the extremal dependence of the risk factors and also the ease with which the parameters of the t-copula can be estimated from data. In Frey Rüdiger et al., "copulas and credit models" RISK, October 2001, p.p. 111-114, the use of such t-copulas for modelling credit portfolio losses is described. The disclosure thereof is herein implemented by reference.
We will recall therefore only the basic definitions and properties of t-distributions and t-copulas. For more on copulas in general, see NELSEN, R. (1999): An Introduction to copulas. Springer, New York, or EMBRECHTS, P., A. MCNEIL, AND D. STRATTON (2002): "Correlation and Dependence in Risk Management: Properties and Pitfalls," in Risk Management: Value at Risk and Beyond, ed. By M. Dempster, pp. 176-223. Cambridge University Press, Cambridge.
Before describing the state of the art and the present invention in greater detail it is helpful to define the various variables and values. The following notation is used in the description of the prior art as well as of the invention:    d dimension, number of risk factors    Rd the d-dimensional usual real vector space    E(X) expected value of the random variable X    Var(X) variance of the random variable X    Cov (X,Y) covariance of the random variables X and Y    X,Y,Z random vectors    Cov(X) covariance matrix of X    ν number of degrees of freedom    Σ covariance matrix    Nd(0,Σ) d-dimensional Gaussian distribution with mean 0 and covariance Σ    φ univariate Gaussian distribution function    χν2 Chi Square distribution with degree of freedom ν    ρ correlation matrix    tν Student's t distribution function with degree of freedom ν    tν−1 Student's t quantile function    tν,ρd Student's t d-dimensional distribution function with correlation matrix ρ and degree of freedom ν    Γ usual gamma function    det A determinant of matrix A    Hk arbitrary univariate distribution function    U random variable uniformly distributed on [0,1]    τ(X,Y) Kendall's tau rank correlation for random variables X and Y    ak credit multi-factor model parameters    P└A┘ probability of occurrence of event A P└X≦x┘ probability that X is lower or equal than x    λk counterparty idiosyncratic parameter    Ek credit exposure on counterparty k    lk loss given default
Let Z˜Nd(0,Σ) and U (random variable uniformly distributed on [0,1]) be independent. Furthermore, G denotes the distribution function of √{square root over (ν|xν2)} and R=G−1(U).
Then the Rd—valued random vector Y given byY=(RZ1,RZ2,RZ3, . . . ,RZd)′  (1)has a centered t-distribution with ν degrees of freedom. Note that for ν>2,
      Cov              (      Y      )        =            v              v        -        2                        Σ      .      By Sklar's Theorem, the copula of Y can be written asCν,ρt,(u)=tν,ρd(tν−1(u1), . . . ,tν−1(ud)),  (2)where ρi,j=Σij/√{square root over (ΣiiΣjj)} for i, jε{1, . . . , d} and where tν,ρd denotes the distribution function of √{square root over (ν)}Z/√{square root over (S)}, where S˜xν2 and Z˜Nd(0,ρ) are independent (i.e. the usual multivariate t distribution function) and tν denotes the marginal distribution function of tνρ,d (i.e. the usual univariate t distribution function). In the bivariate case the copula expression can be written as
                                          C                          v              ,              ρ                        t                                          (                          u              ,              v                        )                          =                              ∫                          -              ∞                                      t              v                                                -                  1                                                                  (                  u                  )                                                                                ∫                              -                ∞                                            t                v                                                      -                    1                                                                          (                    v                    )                                                                                1                                  2                                                                              π                                                                    (                                                  1                          -                                                      ρ                            12                            2                                                                          )                                                                                1                      /                      2                                                                                {                                      1                    +                                                                                s                          2                                                -                                                  2                                                                                ρ                            12                                                                              st                                                +                                                  t                          2                                                                                v                                                                          (                                                      1                            -                                                          ρ                              12                              2                                                                                )                                                                                }                                                                      -                                          (                                              v                        +                        2                                            )                                                        /                  2                                                                                ⅆ                s                                                                                ⅆ                  t                                .                                                                        (        3        )
Note that ρ12 is simply the usual linear correlation coefficient of the corresponding bivariate tν-distribution if ν>2. The density function of the t-copula is given by
                                                        c                              v                ,                ρ                            t                                                  (                                                u                  1                                ,                …                                                                                ,                                  u                  d                                            )                                =                                    1                                                det                                                                                ρ                                                                                Γ                                                              (                                                                        v                          +                          d                                                2                                            )                                                                                Γ                                                                    (                                                  v                          2                                                )                                                                                d                      -                      1                                                                                Γ                                                              (                                                                        v                          +                          1                                                2                                            )                                                        d                                            ·                                                                    ∏                                          k                      =                      1                                        d                                                                                (                                              1                        +                                                                              y                            k                            2                                                    v                                                                    )                                                                                v                        +                        1                                            2                                                                                (                                          1                      +                                                                                y                            ′                                                                                ρ                                                          -                              1                                                                                y                                                v                                                              )                                                                              v                      +                      d                                        2                                                                                ,                            (        4        )            where yk=tν−1(uk).
Let H1, . . . , Hd be arbitrary continuous, strictly increasing distribution functions and let Y be given by (1) with Σ a linear correlation matrix. Thenx=(H1−1(tν(Y1)), . . . ,Hd−1(tν(Yd))′  (5)has a tν-copula and marginal distributions H1, . . . , Hd. The distribution of X is referred to as a meta-t distribution. Note that X has a t-distribution if and only if H1, . . . , Hd. are univariate tν-distribution functions.
The coefficient of tail dependence expresses the limiting conditional probability of joint quantile exceedences. The t-copula has upper and lower tail dependence with ( tν+1(x)=1−tν+1(x)):λ=2 tν+1(√{square root over (ν+1)}√{square root over (1−ρ12)}/√{square root over (1+ρ12)})<0,in contrast with the Gaussian copula which has λ=0. From the above expression it is also seen that the coefficient of tail dependence is increasing in ρ12 and, as one would expect since a t-distribution converges to a normal distribution as ν tends to infinity, decreasing in ν. Furthermore, the coefficient of upper (lower) tail dependence tends to zero as the number of degrees of freedom tends to infinity for ρ12<1.
The calibration of the copula parameters (ρ,ν) are typically done as follows:
(i) Kendall's tau ρ(Xi,Yj) is estimated for every pair of risk factor log returns. An estimate of the parameter ρ in (2) is obtained from the relation
                              τ                                (                                          X                i                            ,                              Y                j                                      )                          =                              2            π                                          arcsin                                      (                              ρ                ij                            )                                                          (        6        )            which holds for any distribution with strictly increasing marginal distribution functions and a copula of an elliptical distribution which has a density, i.e. essentially any meta-elliptical distribution one would consider in applications. Note that in high-dimensional applications an estimate of obtained from (6) may have to be modified to assure positive definiteness. This can be done by applying the so-called eigenvalue method, i.e. the negative eigenvalues are replaced by a small positive number. Other calibrations are possible too.
(ii) Transforming each log return observation Xi with its respective distribution function, e.g. gaussian N1(0,σi) yields, under the meta-t assumption, a sample from a t-copula with known ρ-parameter. Finally, the degrees of freedom parameter ν is estimated by standard maximum likelihood estimation using (4).
In step (ii) the empirical marginals or fitted distribution functions from a parametric family can be used.
The simulation from t-copula comprises the following steps:
(i) Draw independently a random variate Z from the d-dimensional normal distribution with zero mean, unit variances and linear correlation matrix ρ, and a random variate U from the uniform distribution on (0,1).
(ii) Obtain R by setting R≈Gν−1(U). By (1) we obtain a random variate Y from the t-distribution.
(iii) Finally,(tν(Y1), . . . ,tν(Yd))′is a random variate from the t-copula
This meta-t assumption makes sense for risk factors of similar type, e.g. foreign exchange rates. However, it was found that it does not accurately describe the dependence structure for a set of risk factor log returns where the risk factors are of very different type, for example a mixture of stock indices, foreign exchange rates and interest rates.
It is a general problem of such models, that the number of available historical data is quite small, so that at least the tail dependency can hardly be modelled. Similar problems are also known in other fields, for example in the combination reinsurance portfolios, the reliability of industrial complexes or in the weather forecast.

System and method for performing risk analysis


Disclosed herein is a low-power wireless charging apparatus including: a plurality of primary coils corresponding to a plurality of receivers, respectively; a plurality of drivers periodically and sequentially transmitting receiver detect signals; a sensing unit detecting a current and a voltage according to a magnetic field changed by one or more of the plurality of primary coils; a comparator comparing the detected current and voltage with pre-set values; a low-power auxiliary control unit generating a wake-up signal when one or more receivers are present; and a main control unit turned on upon receiving the wake-up signal, and controlled to generate a wireless power signal for charging a corresponding receiver and transmit, whereby unnecessary power consumption can be prevented and the burden of the main control unit can be lessened, thus increasing efficiency.

1. Technical Field
The present invention relates to a low-power wireless charging apparatus and a method thereof.
2. Description of the Related Art
In general, the majority of wireless communication devices require charging; however, the recently launched mobile devices have different types of wired connectors.
In order to overcome user inconvenience of charging mobile devices in a wired manner, a wireless charging technique has quickly progressed.
The wireless charging technique is performed using a magnetic resonance scheme and a magnetic induction scheme.
In particular, the magnetic resonance scheme allows for configuration of a system that can be charged at a distance, but since it is transferrable to a human body or a different device, harmfulness thereof remains to be solved in the future.
Meanwhile, the magnetic induction scheme is a power transmission scheme using electromotive force induced from a magnetic field. Since the magnetic induction scheme can transmit power only within a short distance of a few millimeters or a few centimeters, it is considered not to be harmful to the human body in comparison to the power transmission scheme using magnetic resonance.
For this reason, development of the wireless charging technique employing the magnetic induction scheme and propagation of corresponding products have been quickly promoted.
In a related art wireless charging apparatus and method using the magnetic induction scheme, it is determined whether or not there is a receiver desired to be wirelessly charged and, when a receiver to be wirelessly charged is detected, the receiver is authenticated whether or not it is a predefined one, and then, a wireless power signal is generated and transmitted to the receiver so that the receiver can be charged with power as much as required.
Namely, in the related art wireless charging apparatus and method, wireless power is charged in the receiver in order of detecting the receiver, authenticating the receiver, generating wireless power, and transmitting the wireless power to the receiver, and all of these processes are performed by a single control unit (e.g., a main control unit).
In particular, in order to detect the receiver, the controller must periodically and continuously transmit a receiver detection signal at certain time intervals, and when the wireless charging apparatus can simultaneously charge a plurality of receivers, the wireless charging apparatus commonly uses a method of continuously transmitting a detection signal at certain time intervals in order to detect receivers and detecting an impedance variation reflected from a resonator (or coil) by a voltage or a current sensor.
Thus, the related art wireless charging apparatus and method consume much power in detecting receiver(s).

Low-power wireless charging apparatus and method thereof


The present invention provides a method for measuring an amount of LDL-cholesterol in samples specifically and accurately and also a reagent used for the method, and by using the present invention, such effect can be attained that LDL-cholesterol can be measured directly using so far widely used automatic analyzer, which has been impossible in known measurement methods.

The present invention relates to a method for measuring an amount of cholesterol in low density lipoproteins (LDL), which has been used for important factor for diagnosis of arteriosclerosis, disorder of lipid metabolism, etc. in the field of clinical chemistry test and also to a reagent used in this method.
Lipids in serum exist as lipoproteins and they are classified according to their density into chylomicrons, very low density lipoproteins (VLDL), LDL and high density lipoproteins (HDL). They are particles comprising proteins covalently bound to lipids and have a micelle-like spherical structure composed of a non-polar core consisting of triacylglycerol and cholesterol ester on one hand and proteins, cholesterol and phospholipid covering the core on the other hand, and apoproteins and lipids are different according to each lipoprotein. LDL has a particle size of about 180 to 280 angstroms in diameter and specific gravity of a range of 1.006 to 1.063 (g/ml) and its apoprotein is composed mainly of apoB-100, and 80% thereof is occupied by lipid which contains a large amount of cholesterol. On the other hand, HDL is the smallest lipoprotein having a particle size of about 50 to 120 angstroms in a diameter and such higher specific gravity as 1.063 to 1.125 (g/ml), which is enriched with proteins (mainly apoA, about 50% thereof) containing lipid composed of mainly phospholipid and cholesterol. LDL has a role of transporting cholesterol synthesized in liver to peripheral cells and HDL has, on the other hand, a role of transporting it from peripheral tissues to liver.
Among those lipoproteins, LDL has an action causing atherosclerosis which is most frequently found among arteriosclerosis (progressive disease caused by sedimentation of lipids in cells of smooth muscles in inner walls of arteries, particularly of coronary arteries), and thus an amount of cholesterol originated therefrom (LDL-cholesterol) has been remarked as a risk factor of arteriosclerosis.
However, there has been found no method for measuring LDL-cholesterol accurately after a simple procedure.
For instance, LDL-cholesterol amount obtained by the following equation proposed by Friedewald, etc. has been said as containing about 10% error; EQU LDL-cholesterol amount=total cholesterol amount-HDL-cholesterol amount-1/5.times.triglyceride amount

Reagent and methods for measuring LDL-cholesterol


A hetero-junction semiconductor device includes: a channel layer that includes a first semiconductor; a barrier layer that is provided on the channel layer and includes a semiconductor having a band gap larger than a band gap of the first semiconductor; a source electrode and a drain electrode that are provided on the barrier layer and are ohmic contacted to the barrier layer; a p-type semiconductor layer provided on the barrier layer, the p-type semiconductor layer being provided in a region between the source electrode and the drain electrode on the barrier layer; an n-type semiconductor layer that is provided on the p-type semiconductor layer; and a gate electrode that is joined to the n-type semiconductor layer. A joint interface between the p-type semiconductor layer and the n-type semiconductor layer has a concavo-convex structure.

1. Field of the Invention
The present invention relates to a hetero-junction semiconductor device and a method of manufacturing a hetero-junction semiconductor device.
2. Description of Related Art
Disclosed is a nitride semiconductor device which is a hetero-junction semiconductor element device in which a channel layer formed of gallium nitride (GaN) and a barrier layer formed of aluminum gallium nitride (AlGaN) are joined to each other. In this nitride semiconductor device, a p-type GaN layer, an n-type GaN layer, and a gate electrode are laminated on the barrier layer (Japanese Patent Application Publication No. 2013-80894 (JP 2013-80894 A).
In the nitride semiconductor device according to the above-described related art, the dopant concentration in the p-type GaN layer may be set to be high such that the device is made to be in an off state (normally-off state) in a state where a voltage is not applied to the gate electrode. In addition, the dopant concentration in the n-type GaN layer may be set to be high such that contact resistance with the gate electrode is reduced.

Hetero-junction semiconductor device and method of manufacturing a hetero-junction semiconductor device


A technique and system for isolating segments of a serial data bus for remote configuration of equipment in in-flight entertainment systems. The system allows the automatic initialization, or configuration, of multiple terminal units, attached to a serial data bus, without requiring physical access to the multiple units.

1. Field of the Invention
This invention relates generally to a technique for isolating segments of a serial data bus. More particularly, this invention relates to an automatic system for initializing, or configuring, multiple terminal units, attached to a serial data bus, without requiring physical access to the plurality of remote terminal units, each of which may be located at or near a passenger seat of a passenger vehicle, such as an aircraft, train or bus, for example, or in a theater or stadium or the like.
2. Background of the Invention
In-flight entertainment systems commonly installed in modern passenger aircraft provide both increased passenger satisfaction as well as a revenue stream to airlines, by making a number of entertainment options available to the passengers. Well-known systems such as those shown, for example, in U.S. Pat. Nos. 4,866,515 (Tagawa) and 4,835,604 (Kondo), disclose a number of methods of providing audio and video in-flight entertainment to airline passengers.
It should be appreciated that the need to have the ability to easily and quickly configure each of the individual units or components, of an in-flight entertainment system, once installed in an aircraft, is invaluable. For example, in many instances the misconfiguration of a component in an in-flight entertainment system will result in the need for corrective action which requires disassembly of interior aircraft cabin panels. These corrective actions may result in aircraft departure delays, or, the misconfigured component may cause the entire system to be inoperative. Even if the initial installation of the system is correctly performed, the maintenance and upkeep of the system normally requires periodic physical access to the individual components.
Although various manual methods of addressing and configuration of individual video distribution units have been known for quite awhile, the problem of manually performing these functions has become more significant in the recent past in view of the increase in complexity of onboard electronic systems and the decrease in space and weight allotted to such systems. These factors greatly increase the cost, in both time and equipment, in both installation and maintenance of the system.
Known methods of initializing individual units attached to a serial data bus include physically accessing each unit and configuring each unit manually with, for example, DIP switch settings, internal configuration jumpers or plugs, jumpers in the cable harness, etc. However, as discussed, the standard "manual" approaches are both uncertain and inefficient. The present invention addresses each of these needs.

Method and apparatus for connecting several video distribution units to a serial data bus


An ATM switch is used to combine blocks of data from multiple data servers into a single continuous data stream. The ATM switch is especially well adapted for use in a video-on-demand environment. Blocks of data may be striped across the data servers so that they are output from respective data servers in sequence. Transmission of data from the data servers to the ATM switch is scheduled so that the blocks of data are output in sequence without undue delay between the transmission of blocks of data from the servers. Synchronizing tokens are provided to the data servers to specify that they are to output data of a given sequence and to direct the sequence to a given virtual channel. As a result, the system of this invention appears to output single continuous data streams from the output ports of the ATM switch.

Asynchronous transfer mode (ATM) is one of a general class of high-speed packet switching technologies that route traffic via an address contained within each packet. Asynchronous transfer mode may be contrasted with synchronous transfer mode techniques that are used in many digital telephone networks. Asynchronous transfer mode is an outgrowth of the broadband integrated services digital network (BISDN) standards that have been developed. ATM switches have been developed to control routing in ATM environments. These switches route fixed size packets, known as cells, to their intended destinations. Generally, ATM switches are used to realize a connection from a single origination point to a single destination point.

Method and system for combining data from multiple servers into a single continuous data stream using a switch


Excellent water repellency and Oil repellency are imparted to a textile by a method including    (1) preparing a treatment liquid comprising a water- and oil-repellent agent,    (2) adjusting pH of the treatment liquid to at most 7,    (3) applying the treatment liquid to a textile,    (4) treating the textile with steam, and    (5) washing the textile with water and dehydrating the textile, wherein the water- and oil-repellent agent comprises at least one fluorine-containing compound selected from the group consisting of a fluorine-containing polymer and a fluorine-containing low molecular weight compound, and the water- and oil-repellent agent or the treatment liquid contains a cationic emulsifier and/or a salt.

Hitherto, various treatment methods have been proposed in order to impart water repellency, oil repellency and soil releasability to a textile such as a carpet. For example, a process (hereinafter, sometimes referred to as "Exhaust process") of treating a textile comprising decreasing a pH of a treatment liquid, applying the treatment liquid to the textile, thermally treating the textile with steam, washing the textile with water, and dehydrating the textile is proposed.
A method comprising the Exhaust process is proposed in U.S. Pat. Nos. 5,073,442, 5,520,962, 5,516,337 and 5,851,595 and International Publication WO 98/50619.
U.S. Pat. No. 5,073,442 discloses a method of treating a textile, comprising conducting an Exhaust process by using a water- and oil-repellent agent comprising a fluorine-containing compound, a formaldehyde condensation product and an acrylic polymer. U.S. Pat. Nos. 5,520,962 and 5,851,595 disclose a method of treating a carpet, comprising conducting an Exhaust process by using a fluorine-containing compound and a polymeric binder. U.S. Pat. No. 5,516,337 discloses a method of treating a textile, comprising conducting an Exhaust process by using a fluorine-containing water- and oil-repellent agent and a metal compound such as aluminum sulfate. International Publication WO 98/50619 discloses a method of treating a carpet, comprising conducting an Exhaust process by using a fluorine-containing water- and oil-repellent agent and a salt such as a magnesium salt.
These methods mainly use the water- and oil-repellent agent in combination with the stain-blocking agent and can give water repellency and oil repellency when using the Exhaust process.

Water- and oil-repellent treatment of textile


An aspect of the disclosure is to provide a method and a hearing aid system comprising; a microphone unit configured to receive an acoustical input and provide an audio signal based on the acoustical input, and wherein the audio signal includes a sound pressure level; a storing unit including a normal hearing loudness model, a loudness scheme, a stimulation model and a coding parameter model; a sound output unit configured to stimulate auditory nerve fibers of a recipient of the hearing aid system based on audible stimulations; a processing unit configured to; extract a normal hearing loudness based on the sound pressure level and the normal hearing loudness model, and the normal hearing loudness model includes a plurality of normal hearing loudness as a function of a plurality of sound pressure levels; transform the normal hearing loudness to a secondary hearing loudness according to a loudness scheme; determine a stimulation level within a dynamic range of a recipient of the hearing aid system based on the secondary hearing loudness and the stimulation model, where the stimulation model includes a relation between a plurality of stimulation levels and a plurality of secondary hearing loudness; determine one or more stimulation coding parameters based on the coding parameter model, where the coding parameter model includes a relation between the determined stimulation level and the one or more stimulation coding parameters; and wherein the processing unit is configured to generate the audible stimulations based on the determined one or more stimulation coding parameters and provide the audible stimulations via the sound output unit to the auditory nerve fibers of the recipient of the hearing aid system such that the recipient perceives the secondary hearing loudness.

A hearing aid that system is adapted to improve or augment the hearing capability of a recipient by receiving an acoustic signal from a recipient's surroundings, generating a corresponding audio signal, possibly modifying the audio signal and providing the possibly modified audible signal as an audible signal to at least one of the recipient's ears or auditory nerve fibers of the recipient's cochlea. Such audible signals may be provided in the form of an acoustic stimulation transferred to the recipient's ear via a speaker, or provided in the form of an electrical stimulation transferred to the recipient's auditory nerve fibers via an electrode array, or provided in the form of a mechanical stimulation transferred to the recipient via a vibrator transferring the mechanical stimulation in the form of vibrations into the skull of the recipient.
The different types of hearing aid systems may be used together in any combinations, and each of them are fitted differently resulting in different perceived hearing loudness provided by the stimulation applied to the recipient's ear or cochlea. The recipient will perceive different loudness on both ears which unfortunately results in acoustical discomfort when receiving stimulation on both ears.

Generalized method for providing one or more stimulation coding parameters in a hearing aid system for obtaining a perceivable hearing loudness


A fiber optic communication system comprising:                an optical signal source adapted to produce a frequency modulated signal; and        an optical spectrum reshaper (OSR) adapted to convert the frequency modulated signal into a substantially amplitude modulated signal, wherein the optical spectrum reshaper is adapted to compensate for at least a portion of a dispersion in a transmission fiber;        and further including a transmission fiber coupled to the optical source, a receiver and a decision circuit coupled to the transmission fiber.

A typical fiber optic transmission system is shown in FIG. 1 and includes an optical transmitter 1002, a transmission fiber 1003, and a receiver 1004.
In a digital communications application, a key figure of merit for a transmitter in a communications link is its bit error rate (BER) performance, which is measured by a standard receiver.
More particularly, in a systems test, a known pattern of digital 1 and 0 bits is generated by a pattern generator 1001, converted to optical digital signal 1006 by the transmitter 1002, and injected into the communications link, e.g., fiber 1003. The data coming out of transmitter 1002 is often shown on a sampling oscilloscope in the form of an "eye diagram" 1006, as illustrated in FIG. 1. The "eye" diagram is generated by superimposing the pulse train repeatedly on itself, each time shifting it by one bit period. The top "rail" represents the 1s and the bottom "rail" rail represents the 0 bits. The data coming out of fiber 1003 can be shown on a sampling oscilloscope in the form of another optical eye 1020, and may be distorted by fiber dispersion. The receiver 1004 converts the optical signal into a corresponding electrical signal and determines if the bits are 1s or 0s using a decision circuit, which distinguishes is as signals above a certain preset decision threshold and 0s as signals below the threshold.
In a systems test, an error detector 1005 counts errors: the number of 1s that were intended as 0s and vice versa per unit time. This is called the bit error rate (BER). The error rate is measured as a function of the received optical power into the receiver, since the error rate is a function of the noise in the receiver as well as distortions in the eye.
A transmitter is typically characterized by its BER without fiber transmission, the so-called back-back BER, and its BER after transmission. FIG. 2 shows a BER curve versus received power for a particular transmitter. In FIG. 2, the back-back BER is shown at 1020 and BER after transmission is shown at 1021. The power penalty is shown at 1022. As is typical, the bit error rates for both back-back and after transmission reduce with increasing optical power, since the signal-to-noise ratio increases with increasing optical power. The optical power at which a certain back-back BER (typically 10−12) is achieved is called the sensitivity 1023 and is determined by a transmitter-receiver pair. The sensitivity of a receiver is defined as the sensitivity achieved with an optimal transmitter, typically an externally modulated LiNbO3 transmitter, which produces well defined pulses with high contrast ratio and little distortion without transmission though fiber. The distortions caused by fiber dispersion degrade the transmitted BER 1021 (here after 96 km of standard fiber) and increase the received optical power required to achieve a 10−12 BER. The difference between the back-back sensitivity and the sensitivity after transmission is called the dispersion penalty and is measured in dB. In the present example, the dispersion penalty is 1.5 dB.
Both transmitter and receiver are optimized in order to reduce the dispersion penalty to a desired value. Telecommunication standards at present call for a dispersion penalty of <2 dB. If the back-back sensitivity of the transmitter is worse than the receiver sensitivity, there is an additional back-back penalty, which reduces the overall power budget. The optical power budget is the sum of the optical loss and dispersion penalties, as well as any margin that the system may impose.
It is, therefore, generally desirable to optimize a transmitter (in order to meet the desired power budget) by reducing both the back-back penalty and the dispersion penalty.
A system for long-reach lightwave data transmission through optical fibers has been described in U.S. patent application Ser. No. 10/289,944, filed Nov. 06, 2002 by Daniel Mahgerefteh et al. for POWER SOURCE FOR A DISPERSION COMPENSATION FIBER OPTIC SYSTEM, which patent application is hereby incorporated by reference. Azna LLC of Wilmington, Mass. sometimes refers to the transmitter apparatus of this patent application as a Chirp Managed Laser (CML™). In this system, a frequency modulated (FM) source is followed by an optical discriminator, also sometimes referred to as an optical spectrum reshaper (OSR), which converts frequency modulation into a substantially amplitude modulated (AM) signal and partially compensates for the dispersion in the transmission fiber.
Also, in U.S. Provisional Patent Application Ser. No. 60/629,741, filed Nov. 19, 2004 by Yasuhiro Matsui et al. for OPTICAL SYSTEM COMPRISING AN FM SOURCE AND A SPECTRAL RESHAPING ELEMENT, which patent application is hereby incorporated herein by reference, there is disclosed a CML™ system that can be adapted to transmit a digital signal across >200 km, at 10 Gb/s, in a standard fiber having a net dispersion of 3200 ps/nm. This is approximately twice as far as can be achieved using a standard external modulated transmitter. In this patent application, it is disclosed that the amplitude and frequency profile of the transmitted signal can be adjusted so as to reduce the BER after transmission through dispersive fiber.
It is an object of the present invention to further decrease the bit error rate of the transmitted signal after propagation through fiber by adjusting certain parameters of the receiver in conjunction with the parameters of the transmitter.

Chirp managed laser fiber optic system including an adaptive receiver


A security system for disconnected automation devices comprises a central access control authority that provides access regulations that are received by a portable unit. An analysis component that determines whether access should be provided to a disconnected system based at least in part upon the access regulations. In accordance with an aspect of the present invention, for example, the access regulations can restrict access to a disconnected device for a particular timeframe.

Advancements in technology have enabled factory applications to become partially or completely automated. For example, applications that once required workers to put themselves proximate to heavy machinery and other various hazardous conditions can now be completed at a safe distance from such hazards. Further, imperfections associated with human action have been minimized through employment of highly precise machines. Many of these factory devices supply data related to manufacturing to databases that are accessible by system/process/project managers on a factory floor. For instance, sensors can detect a number of times a particular machine has completed an operation given a set amount of time. Further, sensors can deliver data to a processing unit relating to system alarms. Thus, a factory automation system can review collected data and automatically and/or semi-automatically schedule maintenance of a device, replacement of a device, and other various procedures that relate to automating a process.
Often, it is impractical to network each device in an automation system to a central facility/system. In other words, frequently several devices/systems employed in an automation context are disconnected from a centralized automation system. Particularly, automation systems that include security features can include a plurality of disconnected devices, wherein such devices are associated with security that either permits or denies access to a disconnected device. For instance, upon entering a correct username and password to a disconnected device, a technician or other user can obtain complete access to the disconnected device. These stand-alone control systems are typically distributed and can be isolated from any centralized supervision. Examples of these systems include portable batch machines, vending machines, door and lift controls for a vehicle (e.g., a bus, a subway car, . . . ), ski lifts, roller coasters, etc. To provide these systems with constant access to a network would be extremely costly. For instance, in the case of a vending machine at a particular geographic location, a substantial amount of cabling and/or expensive wireless peripherals would be required to enable constant network access to such machine. Similarly, structural issues arise when attempting to network all devices and/or systems utilized in a roller coaster and/or ski lift.
While it is often impractical to provide these and other similar devices with advanced networking capabilities, it is often imperative that these machines be associated with adequate security. For example, portable batch machines can be employed in connection with manufacturing a pharmaceutical, food product, and/or other ingestible item. Further, these portable batch machines can include a recipe that is employed in connection with manufacturing such ingestible items. Insufficient security could allow an unauthorized user to manipulate the recipe or data relating to the recipe within the batch machine, thus compromising safety of those who consume products manufactured based upon the recipe. In another example, insufficient security with respect to a roller coaster and/or ski lift can result in horrendous tragedy. For a specific example, if inadequate security exists with respect to a roller coaster, a technician can accidentally modify a control system with respect to speed control and/or braking. Particularly, a controller that is employed to control brakes at a particular curve can be accidentally manipulated, thereby turning off such brakes or providing insufficient braking. Accordingly, passengers of the roller coaster can be placed in extreme peril. Security is conventionally provided to such devices by implementing security-related functionality at time of manufacture of the disconnected devices. For instance, a vending machine can include data storage and processing capabilities, and user access requirements can be stored in the data storage. Specifically, a user-name and pin number can be required for a user who desires access to an infrastructure of the vending machine. Thereafter the technician can operate on disparate aspects of such vending machine without causing security features to trigger, such as generation of an alarm. Problems arise, however, when a new technician requires access to the vending machine and/or when a technician no longer desirably has access to such machine (e.g., the technician changes jobs, the technician's employment is terminated, the technician retires, . . . ). Accordingly, access privileges often require alteration to maintain security of a disconnected device and/or system.
Conventional security systems require a security technician to travel to individual machines to alter security regulations. Thus, for instance, if a technician whose employment was terminated had access to a plurality of disconnected devices in a geographic region, each of the disconnected devices must be visited to alter access privileges. This individual alteration is costly in terms of both monetary expense and time-loss of a qualified technician. Specifically, both money and resources are spent during a technician's visit to a plurality of disparate locations in order to maintain security of the disconnected devices. Further, there is a storage burden relating to these disconnected devices, wherein sufficient data storage capabilities are required to retain access information for each individual who is authorized to access the system/device.
In view of at least the above, there exists a need in the art for a system and/or methodology for providing an efficient security system with respect to disconnected devices.

Access control method for disconnected automation systems


The invention offers an electrode material that can accomplish both high capacity and high output and a battery, a nonaqueous-electrolyte battery, and a capacitor all incorporating the electrode material. The electrode material has a sheet-shaped aluminum porous body carrying an active material. The above-described aluminum porous body has a skeleton structure that is formed of an aluminum layer and that has a vacant space at the interior. When observed by performing cutting in a direction parallel to the direction of thickness of the sheet, the above-described vacant space in the skeleton structure has an average area of 500 μm2 or more and 6,000 μm2 or less.

Aluminum is a material that is excellent in conductivity and corrosion resistance and is lightweight. In battery application, for example, as the positive electrode of a nonaqueous-electrolyte battery such as a lithium-ion battery, an aluminum foil is used by applying on its surface an active material such as lithium cobalt oxide. More specifically, a paste-like material formed by mixing a conductive aid, binder resin, and the like with a powder of active material such as lithium cobalt oxide is applied onto both surfaces of an aluminum foil and then dried to produce a positive electrode (Patent Literature 1).
On the other hand, a metallic porous body having a three-dimensional network structure is used in applications such as various filters and battery electrode. For example, CELMET (Registered trademark of Sumitomo Electric Industries, Ltd.) made of nickel is used as an electrode material of batteries such as a nickel-hydrogen battery and a nickel-cadmium battery. When such a metallic porous body is used as an electrode, the metallic porous body is filled with a paste-like material formed by mixing a conductive aid, binder resin, and the like with an active material to produce the electrode. For example, Patent Literature 2 describes an alkaline battery's electrode formed by filling a collector formed of a metallic porous body with an active material.

Electrode material; and battery, nonaqueous-electrolyte battery, and capacitor all incorporating the material


A carrier injection type light emitting element with employment of a pn junction established between porous silicon and a semiconductor having a conductivity type different from that of the porous silicon, and also optical devices such as an opto-optical converting element, a light transmitting element, a photocoupling circuit element, a photocoupling element and a display apparatus, which comprise such a carrier injection type light emitting element and a semiconductor light receiving element.

1. Field of the Invention
The present invention generally relates to a light emitting element employing porous silicon and an optical device utilizing the light emitting element. More specifically, the present invention is directed to a charge injection type light emitting element (LED) having a pn junction employing porous silicon, and also to an optical device such as an opto-optical converting element, a light transmitting element, a photocoupling circuit element, a photocoupling element and a display device, which contain, in principle, such a light emitting element.
2. Description of the Related Art
Conventionally, it is considered that since a silicon semiconductor corresponds to an indirect interband transition semiconductor, a light emitting element could not be manufactured by employing such a silicon semiconductor. As a consequence, the conventional light emitting elements with employment of the pn junction have been manufactured by the III-V group compound semiconductor, II-VI group compound semiconductor, and IV-VI group compound semiconductor. However, there are many materials to manufacture a silicon semiconductor. Silicon semiconductors having large areas can be produced at low cost, and the technique to manufacture single crystal could be established, as compared with those of the compound semiconductor. There are various merits in the silicon semiconductors that logic elements, calculation elements, drive elements, and light receiving elements and the like with high reliability can be assembled on a single substrate at a high integration degree, because of high device designing/manufacturing techniques, which could not be practically realized with the compound semiconductor. Accordingly, strong demands have been made to obtain a light emitting element with employment of silicon, especially a charge injection type light emitting element employing a pn junction, capable of being applied to a laser at a final goal. To the contrary, L. T. Canham reported in 1990 that the porous silicon fabricated by electrochemical anodizing single crystal silicon into a hydrogen fluoride solution, indicates strong photoluminescence at a room temperature (see Applied Physics Letters 57, (10), Sep. 3, 1990, pages 1046-1048). This report implies that a light emitting element may be manufactured by silicon. Thereafter, many researches have been carried out to analyze a generation mechanism of this photoluminescence. However, since no one could find such a material by which a pn junction can be formed with porous silicon at a better characteristic and a light emitting diode (LED) can be manufactured with this pn junction, a charge injection type light emitting element in a pn junction mode with this porous silicon could not be realized.
On the other hand, there are various optical devices such as an opto-optical converting element, a light transmitting element, a photocoupling circuit element, and a photocoupling element. For instance, as disclosed in a Japanese publication "Physics on Optical/Electronic Integrated Circuit" by H. Matsueda, pages 279-309, the plane type light transmitting element is known that the optical transmission unit containing the multilayer light emitting element of GaAs/AlGaAs, and also an FET functioning as a switching modulation element for modulating the light signal sent out from the optical transmission unit in response to an input electric signal are fabricated on a compound semiconductor substrate such as a GaAs substrate and an InP substrate. Also, there has been proposed in "Parallel Process System realized by 3-Dimensional Shared Memory" in Electronics, October 1981, that the light emitting element with employment of the compound semiconductor such as GaAs and the light receiving element are positioned opposite to each other on a single wafer, as the 3-dimensional photocoupling circuit element for performing the data communication among the circuit elements such as memories in the computer by utilizing the light signals.
However, even in the above-described conventional optical devices, since the expensive compound semiconductor substrate is employed, and also the light emitting element is fabricated with the compound semiconductor, the manufacturing cost becomes high and large integration becomes difficult, resulting problems. Therefore, an optical device with employment of a light emitting element made by silicon has been demanded.
Many attempts have been made in that the band structures of the silicon semiconductor are varied by utilizing the quantum effect to emit light. These silicon semiconductors capable of emitting the light have been manufactured by way of the molecular beam epitaxicy (Applied Physics Letter 56, (4), Jan. 22, 1990, pages 340-342), the plasma etching method (Applied Physics Letter 59, 1991, pages 1603-1605), and the RF sputtering method (Physical Review B 38, Sep. 15, 1988, pages 5726-5729). However, since very huge installations are required and very difficult manufacturing techniques are needed, this technique could not practically utilized.

Light emitting element with employment of porous silicon and optical device utilizing light emitting element


In order to defeat pirate descramblers that detect the occurrence of a vertical blanking interval from a gap in timing data provided on the sound carrier of a scrambled television signal, diversionary pulse information is inserted into the sound carrier during the vertical blanking interval. A pirate descrambler that looks for a gap in data transmitted on the sound carrier will then detect a "false" second gap, and incorrectly phase lock its horizontal oscillator to random video instead of to horizontal timing information that is recoverable during the vertical blanking interval.

The present invention relates to the distribution of scrambled television programs over cable television networks or the like, and more particularly to a method and apparatus for preventing the absence of timing information on the sound carrier of a scrambled television signal from being used to detect the vertical interval for recovering horizontal synchronization information.
Techniques for scrambling the video portions of television signals are well known. For example, U.S. Pat. No. 3,813,482 to Blonder discloses a system for transmitting television signals wherein the video is scrambled by suppressing vertical or horizontal synchronization pulses to produce a shifting or rolling scrambled picture. In U.S. Pat. No. 4,542,407 to Cooper, et al, apparatus is disclosed for scrambling and descrambling television programs in which the horizontal synchronizing information is suppressed at a cable television headend, and then regenerated by a subscriber's cable television converter. U.S. Pat. Nos. 4,095,258 to Sperber, 4,163,252 to Mistry, et al, and 4,571,615 to Robbins, et al describe apparatus for decoding scrambled television signals.
The economic viability of subscription television programming, including cable television and satellite television services, is dependent on the ability of the transmitter to encode or scramble a television signal so that an unauthorized receiver will not be able to receive a viewable television picture. As indicated in the patents cited above, a common technique that has been employed to scramble video signals is to suppress the horizontal synchronization pulses below the average value of the video level. This causes the television receiver to unsuccessfully attempt to lock horizontally on random video peaks rather than on the horizontal synchronization pulses. The loss of effective horizontal synchronization also prevents the receiver from properly utilizing the color burst signal associated with the horizontal synchronization pulse, so that accurate color reproduction cannot be achieved.
In order for a receiver to be able to view the scrambled video signal, the suppressed synchronization pulses must be restored. Two techniques are commonly employed to allow the receiver to recover the suppressed sync and timing information. In one technique, a timing pulse is amplitude modulated on the FM audio carrier of the television signal, which is then detected in the audio portion of the receiver and used to generate the timing signals necessary to descramble the received video signal. This technique is the subject of U.S. Pat. No. 4,621,285 issued on Nov. 4, 1986 to Schilling et al and entitled "Protected Television Signal Distribution System", the entire disclosure of which is incorporated herein by reference.
In another known technique, some portion of the sync timing pulses, such as during the vertical blanking interval, is transmitted without suppression, i.e., "in the clear". The receiver phase locks to the clear or unsuppressed sync portion to create the required synchronizing and timing information for descrambling the video portions of the signal.
Neither of these known techniques are immune to unauthorized recovery by "pirate" descramblers. Such descramblers are known that will restore usable synchronization to virtually all known prior art sync suppressed video signals. One such device that can overcome the scrambling technique disclosed in the aforementioned Schilling et al patent relies on the absence of horizontal synchronizing pulse timing information on the sound carrier during the vertical blanking interval portion of the scrambled television signal. The absence of such information is detected, indicating the occurrence of the vertical blanking interval. The pirate descrambler uses this information to locate synchronization pulses on the video carrier during the vertical blanking interval. Such pulses can be detected because there is no video information to mask them during vertical blanking. The detected synchronization pulses are then used to phase lock an oscillator that provides synchronization pulses during the active video portions of the signal.
It would be advantageous to provide a system for scrambling the video portion of television signals that would preclude the detection of the vertical blanking interval from the absence of horizontal synchronizing timing pulses on the sound carrier. Such a system would defeat the ability of pirate descramblers to recover synchronization information during the vertical blanking interval. It would be further advantageous to provide such a system that will not interfere with the descrambling of scrambled signals by the millions of authorized descramblers already installed in the field. The present invention provides such a system.

Method and apparatus for frustrating vertical interval detection in scrambled television signals


Each detection unit is configured to compare a voltage output from a battery cell associated therewith a predetermined criterion voltage. A plurality of detection units operate sequentially in response to a start trigger and also sequentially transmit a signal that reflects a result of comparing the voltages to detect whether a battery pack has a low cell voltage fault. A fault monitoring device detects an internal resistance fault when it receives from a transmission circuit a determination signal indicating that the battery pack when electrically discharged has any of its battery cells outputting a voltage decreased to be lower than the criterion voltage and if a current detected has a value smaller in magnitude than a criterion current corresponding to a value of a current obtained by dividing a difference in voltage between an open circuit voltage of the battery cell and the criterion voltage by an upper limit value for internal resistance.

A battery pack having a large number of battery cells (or battery modules) connected in series is generally used. For example, hybrid vehicles, electric vehicles, and the like employ such a battery pack as a power supply for driving a motor.
Japanese Patent Laying-Open No. 2004-134287 (PTL 1) discloses a failure detection device for such a battery pack. This failure detection device detects whether a battery pack having a plurality of series connected battery cells or a battery pack having a plurality of series connected sets of cell parallel circuits each having a plurality of parallel connected battery cells is electrically overcharged or overdischarged, and the battery pack's internal resistance is estimated and in accordance therewith an overcharge threshold value and an overdischarge threshold value are modified. When a battery cell or a cell parallel circuit has voltage thereacross exceeding the overcharge threshold value, an overcharge detection signal is issued, whereas when a battery cell or a cell parallel circuit has voltage thereacross below the overdischarge threshold value, an overdischarge detection signal is issued.
The failure detection device allowing a battery packs internal resistance to be estimated and an overcharge threshold value and an overdischarge threshold value to be modified in accordance therewith is believed to ensure that whether the battery pack fails can be detected early (see PTL 1).


A method of operating an integrated hydrogen production and processing system is provided. The method includes operating an electrolyzer to produce hydrogen from water and utilizing heat generated from the electrolyzer to increase a temperature of an electrolyte in a first mode of operation. The method also includes heating the electrolyte in a second mode of operation by extracting heat from a hydrogen compressor to increase or maintain the temperature of the electrolyte during periods when electrolysis is not performed in the electrolyzer or during startup of the electrolyzer.

The invention relates generally to hydrogen production and processing systems, and more particularly, to enhancement of performance of an integrated hydrogen production and processing system, that may include, but is not limited to, hydrogen purification, compression, and storage sub-systems.
Various types of hydrogen production systems have been designed and are in use. For example, electrolyzer systems generate hydrogen through electrolysis of water. The hydrogen acts as an energy carrier, and can be converted back to electricity for power generation or distributed for use as a fuel. Typically, hydrogen generated from such systems is purified and compressed for storage before it is consumed in an end use system. Many view future hydrogen applications in terms of energy production with hydrogen being produced through electrolysis for direct use in producing power. For example, the end use system may be of a business or industrial nature where the stored hydrogen is used for power generation through hydrogen-powered internal combustion engines, fuel cells, and turbines. Moreover, the stored hydrogen may be distributed to a consumer for powering a vehicle or for use in certain residential applications such as cooking, and so forth.
In certain systems, an alkaline electrolyzer is used for hydrogen generation. Typically, an alkaline electrolyzer uses a liquid alkaline electrolyte such as potassium hydroxide or sodium hydroxide to facilitate electrolysis of water for generation of hydrogen. Further, the liquid electrolyte is required to maintain a desired operating temperature to ensure efficient operation of the electrolyzer. Moreover, during startup operation of the electrolyzer, the electrolyte is required to be heated to increase the temperature of the electrolyte to the desired operating temperature.
In initiation of operation of certain conventional electrolyzers, relatively long time delays are encountered for the electrolyte to reach the desired operating temperature, thereby resulting in long periods of inefficient operation of the electrolyzer at lower temperatures. In certain systems, an external heat source may be employed to heat the electrolyte to reach or maintain a desired operating temperature more quickly. However, adding an external heat source results in loss of overall efficiency of the system due to the addition of energy during this phase of operation. In certain other systems, the electrolyte is gradually heated solely through ohmic losses in the electrolyzer stack. In such systems, the heating of electrolyte results in substantially longer times to reach the desired steady-state temperature, thus reducing the overall efficiency of the system.
Accordingly, there is a need for an integrated hydrogen production and processing system that has enhanced performance achieved through utilizing heat from an internal heat source to heat the electrolyte in the hydrogen production system. It would also be advantageous to provide a hydrogen production and processing system that reduces the time to reach an optimum operating temperature of the electrolyte.

Integrated hydrogen production and processing system and method of operation


The present invention provides a process for crosslinking of polyallylamine hydrochloride wherein an aqueous solution of polyallylamine hydrochloride is partly neutralized with alkali and epichlorohydrin is added. The aqueous solution is dispersed in an organic medium containing a surfactant. This leads to gelation in individual droplets. The crosslinking in individual gel beads is completed by raising the temperature. The resulting beads are then separated, washed with water, treated with an organic solvent and dried. The method maximizes the yield of crosslinked polyallylamine hydrochloride particles in the range 60-100 mesh.

1. Field of Invention
The present invention relates to an improved process for the preparation of crosslinked polyallylamine. More specifically the present invention relates to a process for crosslinking of aqueous polyallylamine dispersed in an organic medium so as to maximize the yield of crosslinked product in the desired particle size range of 60 to 100 mesh.
2. Background of the Technology
Polyallylamine is a polymer of allylamine. The amine group of the polymer can be functionalized further. The polymer finds a wide range of applications such as flocculants, coatings and additives. It is well known that the monomer mono allyl amine does not polymerize readily as it undergoes degradative chain transfer. Allylamine is therefore converted into its salt such as hydrochloride or sulfate and polymerized in the presence of a free radical initiator. The polymerization of salts of allylamine is described adequately in U.S. Pat. Nos. 6,303,723, 6,787,587, 6,579,933, 6,509,013, 6,083,495, 5,667,775, 5,496,545, which are cited herein by way of reference.
Polyallylamine hydrochloride solutions are then partly neutralized and crosslinked using a wide range of crosslinking agents described in U.S. Pat. Nos. 6,509,013, 6,083,495, 5,667,775, 5,496,545, 4,605,701, which are cited herein by way of reference. The crosslinkers typically used are epichlorohydrin, 1,4 butane diol diglycidyl ether, 1,2 ethane diol diglycidyl ether, 1,3 dichloropropane, 1,2 dichloroethane, succinyl dichloride, dimethyl succinate and toluene diisocyanate. More specifically the partly neutralized polymer of allylamine hydrochloride is crosslinked using epichlorohydrin.
The use of crosslinked polymer for binding phosphates and bile acids is disclosed in U.S. Pat. Nos. 5,496,545, 6,667,775, 6,083,495, 6,509,013, 6,696,087, 6,433,026, 6,423,754, 6,294,163, 6,203,785, 6,190,649, 6,083,497, 6,066,678, 6,060,517, 5,981,693, 5,925,379, 5,919,832, 5,969,090, 5,917,007, 5,840,766, 5,703,188, 5,679,717, 5,607,669.
The crosslinked polymers are formulated in tablets as described in U.S. Pat. Nos. 6,696,087 and 6,733,780. The methods of making phosphate binding polymers for oral administration are described in U.S. Pat. Nos. 6,509,013, 6,083,495, 5,496,545, 5,667,775, more particularly the U.S. Pat. Nos. 5,496,545, 5,667,775, 6,083,495, 6,509,013, 4,605,701, which are cited herein by way of reference.
According to the teaching of the U.S. Pat. No. 6,083,495, the method of crosslinking involves reacting for about 15 minutes polyallylamine with a difunctional crosslinking agent in an aqueous solution as to form a gel and allowing the gel to cure for 18 hours at room temperature. The gel is then fragmented into gel particles in a blender in the presence of isopropanol. The gel particles are then washed repeatedly with water and then suspended in isopropanol, filtered and dried in vacuum oven for 18 hours.
The process of crosslinking in aqueous solution described in above patents, leads to gelation. Curing at room temperature takes a long time. The gel is difficult to break into gel particles and needs application of high shear in special equipments. The gel particles swell when repeatedly extracted with water and need to be treated with isopropanol again prior to drying. The process also consumes large excess of water and isopropanol. The gel particles need to be dried in a vacuum oven for long time.
This is because polymeric gels adhere to each other and equipment surfaces. In order to overcome problems associated, drying is carried out in presence of additives, which are either azeotrope forming solvents or agents which influence surface wetting of the gel particles. The U.S. Pat. No. 6,600,011 describes the spray drying technique for drying of crosslinked polyallylamine, which is claimed to avoid damage to shear sensitive polymer gels, and also enables improved particle size control. The patent also describes the use of a Ystral three stage disperser to achieve the desired particle size.
Drying of the aqueous slurry by spray drying , needs careful control of the feed pressure and temperature. Especially the feed temperature depends on the nature of the feed in that the feed temperature has to be below the glass transition temperature of the hydrogel and needs to be so adjusted as not to degrade the hydrogel. The U.S. Pat. Nos. 6,362,266 and 6,180,754 describe a process for producing a crosslinked polyallylamine polymer having reduced cohesiveness. According to the teachings of the said patents the crosslinking reaction is carried out in a specially designed reactor, which can handle highly viscous solutions and can break the gel into small pieces after gelation. Typically a LIST-Discotherm B reactor is suitable for carrying out the crosslinking reaction which generates easy to handle clumps of gel. The application of high shear is detrimental as it leads to the formation of soluble oligomers.
The dried crosslinked polymer is further ground using a mortar and pestle, a Retsch mill or a Fritz mill. The patents further describe that during the drying stage the hydrogel becomes highly cohesive, which leads to high power consumption to rotate the agitator. The addition of a surfactant is recommended to reduce the cohesiveness during drying. In summary, the crosslinking of polyallylamine in aqueous solution leads to gelation. The gel is then fragmented in blenders into gel particles, which are then treated with water and isopropanol and then dried. It is also reported that the application of high shear contributes to soluble oligomers, which are undesirable. Hence methods have been proposed to minimize the oligomer content in the final product. Also the use of specific equipments like LIST Discotherm B reactor has been suggested for carrying out crosslinking and spray driers for drying the crosslinked polymers. Especially spray drying is a critical operation in that the feed temperature has to be below the glass transition temperature of the crosslinked polymer.
The existing methods of crosslinking polyallylamine polymer need specialized equipments for converting the gel into gel particles and /or drying the gel particles formed.
The polyallylamine hydrochloride salt used for crosslinking in the present invention is reported extensively in the literature. More specifically the synthesis of the polyallylamine hydrochloride polymer is disclosed in the U.S. Pat. Nos. 6,083,495, 5,667,775, 5,496,545, 6,303,723, 4,605,701, 6,509,013, the disclosures of which are incorporated herein by reference.
The polyallylamine hydrochloride polymer used for crosslinking is partly neutralized prior to crosslinking. This is achieved by dissolving the polymer in water and by adding a calculated amount of alkali such as sodium hydroxide or potassium hydroxide either as a solid or as an aqueous solution.
U.S. Pat. No. 6,362,266 reports ion exchange, dialysis nano filtration or ultrafiltration as methods to remove the salt. In the crosslinking processes described in U.S. Pat. Nos. 6,509,013, 5,496,545, 5,667,775, 6,083,495 the salts are removed by extraction with water after the crosslinked polyallylamine polymer obtained in the form of gel is fragmented into gel particles by treatment with isopropanol in a blender. This process involves the treatment of gel mass in blenders in presence of solvents and is not easy to operate.
The process described by the present invention leads to the formation of gel particles, which can be more readily washed either with an organic solvent or water in order to extract the salts. Furthermore, the gel particles formed as a result of the process described herein, do not readily agglomerate and hence can be washed with water and solvent readily and can also be dried more easily.
The crosslinking agents used for the crosslinking of the polyallylamine hydrochloride are extensively described in the U.S. Pat. Nos. 6,362,266, 6,509,013, 5,496,545, 5,667,775, 6,083,495. In the above patents, the crosslinking agent is added to the partly neutralized polyallylamine hydrochloride at room temperature and the crosslinking reaction is allowed to proceed as such. In contrast, according to the procedure described in this invention, it is desirable to cool the neutralized polyallylamine hydrochloride solution in the range 4° C.-10° C. prior to the addition of the crosslinking agent so that the polymer solution does not undergo substantial crosslinking before the dispersion of the aqueous solution into the organic medium is complete and the dispersion of the aqueous phase in the organic phase is readily achieved. The dispersion of the aqueous phase comprising partly neutralized polyallylamine hydrochloride salt and crosslinking agent, in an organic medium is more readily achieved by incorporating a suitable surfactant such as SPAN 85 in the organic medium.
According to the teaching of the U.S. Pat. Nos. 5,667,775, 5,496,545, 6,083,495, 6,509,013, the aqueous polyallylamine solutions to which the crosslinking agent is added, gel in about 15 minutes and the gel is then allowed to cure for 18 hrs at room temperature. The gel is then broken into pieces by putting into a blender with isopropanol. While this treatment can be carried out on the scales described in these patents, these operations are more difficult to carry out on large scales. U.S. Pat. No. 6,362,266 describes the use of LIST-Discotherm B reactor to process high viscosity materials and break the gel into small gel particles.
According to the method of the present invention, the polymer solution containing the crosslinking agent is dispersed in an organic medium before substantial crosslinking takes place. Since the polymer solution is crosslinked in individual liquid droplets to form gel particles, which are suspended in an organic phase, the viscosity of the resulting dispersion is much lower than the viscosity of gel formed when crosslinking is carried out according to the methods previously reported in the literature. The crosslinking of polyallylamine hydrochloride as described herein can be readily carried out in conventional batch reactors provided with stirrers commonly used in the chemical industry.
U.S. Pat. No. 4,605,701 describes the use of chlorobenzene and dichlorobenzene as an organic solvent and a non ionic surfactant sorbitane sesquioleate. However, the use of chlorinated hydrocarbons is being discouraged in view of the environmental damage caused by the chlorinated hydrocarbons. Also high boiling points of solvents such as chlorobenzene and dichlorobenzene render the removal of solvents from the polymer difficult. Accordingly the present invention envisages the use of non chlorinated solvents as organic medium.
Further, the above patent claims the crosslinked homopolymer of monoallylamine having a particle size not more than 2 mm. However, the said patent does not deal any further with the particle size and its distribution and more particularly the importance of the particle size in relation to the properties and applications of the polymer in phosphate binding.
In a surprising development the inventors of the present invention have observed that the phosphate binding capacity of the crosslinked polyallylamine hydrochloride, which is indicative of the ability of the crosslinked polymer to bind with the phosphates in the body, also depends upon the particle size of the dried product. The crosslinking of the polyallylamine hydrochloride in the dispersion medium results in a distribution of the particle sizes. The coarse particles exhibit a lower phosphate binding capacity. The finer particles exhibit a higher phosphate binding capacity. While the coarse particle generated during the process can be further ground to yield product in the desired size range in 60-100 mesh, the grinding process also produces fines, which pass through a 100 mesh sieve. While the phosphate binding capacity of the fines is not significantly different than the particles in the size range 60-100 mesh, the fines are not particularly suitable for the preparation of tablets. It is therefore desirable that the crosslinking of polyallylamine hydrochloride be carried out under conditions wherein the particle size of the crosslinked product produced in the reactor is in the range 60-100 mesh, so that no further processing is required.
There is therefore a need to develop a method for the synthesis of crosslinked polyallylamine which will simplify the manufacturing method, minimize the need for specialized equipments, bring down the need for wash solvents and will thus bring down the manufacturing costs.
According to the method of the present invention, the crosslinking is carried out in the dispersion medium in the presence of a suitable surfactant and the choice of the stirrer and stirring speed such that the yield of the crosslinked product in the size range 60-100 mesh is maximized. If the yield of the product which passes through the 100 mesh sieve and which is retained over 60 mesh sieve is minimized, only a small portion of the product of the reactor will have to be subjected to size reduction and the loss of fines will also be minimum.

Process for the preparation of crosslinked polyallylamine polymer

Council of Scientific of Industrial Research


Disclosed herein is a method of providing a trusted path between a client and a system using an access control processing technique. The method of providing a trusted path between a client and a system includes the step of determining whether access to resources of the system will be permitted or refused on the basis of access control rules and databased attributes set by a security administrator. Thereafter, the client is notified of permission for or refusal of the access in accordance with the result of the determination.

Currently, with the rapid popularization of the Internet and the everyday use of computers, a variety of techniques for enhancing client authentication have been applied to computer networks.
Of those techniques, an authentication technique, in which a smart card and a password are combined together, for example, a magnetic card and a password are used to authenticate a user of an automated teller machine of a bank, is representative. Aside from the above-described authentication technique using the magnetic card, there are widely utilized hardware authentication techniques, such as fingerprint, iris, voice and image identification techniques.
Such client authentication techniques using hardware have an authentication enhancing effect in that the complexity of the authentication is increased. In order to provide more secure authentication, a smart card, which can provide a challenge-response method, is most suitable.
Alternatively, there are proposed a one-time password generation technique that changes a password whenever a client accesses a system so as to prevent the leakage of the password, and an automatic password generation technique that generates a random value in a system. However, these technologies are not widely utilized because of the inconvenience of memorizing a changed password every time.
In the other respect, when a client is authenticated in a password authentication system used for a general UNIX-based system, there may occur information leakage in which, for example, information such as a password is stolen by a third party without a client's knowledge.
That is, a counterfeit login program is executed without a client's knowledge, intercepts the password of the client and outputs a message to show that the client has inputted his password erroneously and a message to request a client to try again (in this case, the outputted message has the same format as a message to request a client to try again in the genuine login program, so the client is cheated by the message and responds to the try-again request). The client authentication is carried out while the genuine login program is executed. While the client inputs the password, a third party can obtain important information such as the password by monitoring the processing of a current process.
As a result, in a client authentication system, the necessity for the provision of a trusted path is increased.
The trusted path plays an important role in an authentication process, which allows a system to confirm that a message is generated by a client and allows information inputted by the client to be transmitted only to the system. The representative example of an authentication technology for providing a trusted path is found in a Microsoft Windows NT login program.
In the above authentication program, while a system is operated, a trusted path is provided with all the other processes being stopped. However, it can be inefficient to stop all the other processes whenever a login program is executed in a system in which a plurality of clients share a variety of resources.
Additionally, in the conventional login program providing a trusted path, there is not provided a technical means and method for determining whether a login program being executed is a normal login program, so there occurs a problem that a highly trusted path is not provided.

Method for providing a trusted path between a client and a system

Electronics and Telecommunications Research Institute