This invention relates to a method of determining stability of unstable equilibrium point (UEP) computed by using BCU method, comprising selecting UEP computed by using BCU method, obtaining a test vector Xtest for the selected UEP, say XUEP using the following equation:Xtest=Xspost+0.99(XUEP−Xspost)                where Xspost is the SEP, and checking boundary condition of XUEP by simulating system trajectory of post-fault original system starting from Xtest.

1. Field of the Invention
The invention relates to the field of electrical power systems, and more particularly to methods for on-line transient stability analysis, on-line dynamic security assessments and energy margin calculations of practical power systems.
2. Description of the Related Art
By nature, power systems are continually experiencing disturbances which may cause power system instability. These disturbances can be classified as either event disturbances or demand disturbances. Event disturbance can be a short-circuit fault, or the loss of a generator, load or transmission line facility, or a combination of the above. Demand disturbance can be load variations at a set of buses, or power transfer between two sets of specified buses, or a combination of these two. Several recent power system blackouts due to disturbances have occurred in several countries, including Belgium, Canada, France, Japan, Sweden and the United States. Modern energy management systems typically do not perform on-line dynamic security assessment (DSA) to ensure the ability of the power system to withstand certain credible contingencies (disturbances). As our society is increasingly dependent on reliable electricity supply and blackouts are becoming more costly when they occur, any violation of stability limits can have huge impacts (financially and physically) on society. Especially in the era of de-regulation, on-line DSA is an important tool that is needed to avoid any potential blackout.
Power systems must be planned and operated to withstand the occurrence of certain credible disturbances. At present, modern energy management systems (EMS) only perform the task of on-line static security assessment but not the task of on-line dynamic security assessment. Hence, modern EMS still can not assess the ability of a power system to withstand credible contingencies (disturbances.) The set of credible contingencies is a collection of disturbances that are likely to occur with potentially serious consequences. The extension of EMS to include on-line dynamic security assessment (DSA) is desirable and is becoming a necessity for modern power systems. This extension is, however, a rather challenging task; despite the consistent pressure for such an extension, partly due to economic incentives and partly due to environmental concerns, performing DSA has long remained an off-line activity. Indeed, from a computational viewpoint, on-line static security assessment needs to solve a large set of nonlinear algebraic equations. On-line dynamic security assessment (DSA) however requires the handling of a large set of nonlinear differential equations in addition to the nonlinear algebraic equations involved in the SSA. The computational effort required in on-line DSA is roughly three magnitudes higher than that for the SSA.
At present, transient stability analysis programs routinely used in utilities around the world are based exclusively on step-by-step numerical techniques. This practice of power system transient stability via the time-domain approach has a long history. Although the time-domain approach, by its nature, has several advantages, it has several disadvantages. For example, the time-domain approach requires intensive, time-consuming computation efforts; therefore the time-domain approach has not been suitable for on-line application. The time-domain approach does not provide information regarding the degree of stability/instability, or how far the system is from transient instability. This piece of information is valuable for both power system planning and operations. Furthermore, the time-domain approach does not provide information as to how to derive enhancement control or preventive control actions for maintaining system stability.
On-line DSA offers multiple engineering and financial benefits. Some examples are listed below: (i) it can avoid potential blackouts, (ii) a power system can be operated with operating margins reduced by a factor of 10 or more if the dynamic security assessment is based on actual system configurations and actual operating conditions, instead of assumed worst-case conditions, as is done in off-line studies. On-line DSA provides such a capability, which is especially significant in that the demands on current power system environments push the operating conditions of power systems not only with low reserve margins but also closer to their stability limits. (iii) On-line DSA can lead to financial benefits. For instance, it can provide accurate transfer capability constrained by transient stability limit. This accurate calculation of transfer capability would allow remote generators with low production cost to be economically dispatched. The cost saving can be significant, e.g. $300K/day, for a mid-size power system.
From a functional requirements viewpoint, on-line DSA must provide the following                Fast stability assessments of a list of credible contingencies        Accurate identification of unstable contingencies which has no post-fault steady-state (Contingencies lead to system collapse)        Accurate identification of unstable contingencies which has negative energy margins (Contingencies lead to system transient instability)        Accurate identification of severe contingencies (with small but positive energy margins)        Contingency screening and ranking for transient stability in terms of energy margin or critical clearing time        Detailed time-domain simulations of selected unstable or severe contingencies (After the initial event of the contingency, the system variables such as rotor angles, rotor frequencies, voltages, currents, power flows should be simulated as the system responds to controls and protection schemes and to other possible operational events such as arm/disarm special protection schemes, enable/disable control functions, or supervisory switching actions)
To significantly reduce the computational burden required for on-line DSA, the strategy of using an effective scheme to screen out a large number of stable contingencies and to only apply detailed simulation programs to potentially unstable contingencies is well recognized. This strategy has been successfully implemented in on-line SSA and can potentially be applied to on-line DSA. Given a set of credible contingencies, the strategy would break the task of on-line DSA into two assessment stages:                Stage 1: Perform the task of fast dynamic contingency screening to screen out contingencies which are definitely stable from a set of credible contingencies        Stage 2: Perform a detailed stability assessment and energy margin calculation of each contingency remaining after Stage 1.
Several research developments in on-line dynamic contingency screening have been reported in the literature. At present, the existing methods for dynamic contingency screening all first perform extensive numerical simulation on a set of credible contingencies using off-line network data in order to capture essential stability features of system dynamical behaviors; they then construct a classifier attempting to correctly classify contingencies on new and unseen network data in an on-line mode. These methods cannot meet the on-line computation requirement as well as reliability requirement.
Recently, a systematic method to find the controlling unstable equilibrium point was developed, called the BCU method, and is disclosed in U.S. Pat. No. 5,483,462 to Chiang [1]. However, it has been found in several numerical studies that the BCU method may fail in the sense that the unstable equilibrium point (UEP) computed by the BCU method may not always lie on the stability boundary of the original post-fault system. Thus, the energy value at the computed UEP which does not lie on the stability boundary of the original post-fault system can not be used as a critical energy for direct stability assessment. Recently, a set of BCU classifiers for the on-line dynamic contingency screening of electric power systems was developed and disclosed in U.S. Pat. No. 5,719,787 to Chiang and Wang [2]. However, numerical simulation results indicate that the BCU classifiers may mis-classify unstable contingencies as stable. For instance, 10 unstable contingencies in a 173-bus power system were mis-classified as stable; hence violating the reliability requirement of a dynamic security classifier.
A set of several improved BCU classifiers for the on-line dynamical security screening of practical power systems were developed, and is disclosed in [3]. The improved BCU classifiers not only meet the five requirements described in [2] for on-line dynamical security assessments. Furthermore, improved BCU classifiers computes energy margins for screened stable contingencies.
At the present time, the only factor that degrades the reliability of the BCU method is that the controlling UEP computed by the BCU method may not always be the true (correct) controlling UEP. However, since the one-parameter transversality conditions, which lie at the heart of the BCU method, are not easily verifiable, one cannot guarantee a 100-percent reliability for the correctness of the CUEPs computed by the BCU method. Hence, new techniques are required which can not only bypass the difficulty of verifying the one-parameter transversality conditions but can also improve the reliability of the BCU method. In this invention, we will present the development of our invented method, termed group-based BCU method, which is to enhance both the reliability and accuracy of the BCU method in computing critical energy values.
We will begin our discussion by introducing the so-called one-parameter transversality conditions on which the theoretical basis of the BCU method is built. Following this, an important issue regarding the verification of the correctness of CUP's computed by the BCU method will be addressed analytically.
2.1 One-parameter Transversality Condition
In the BCU method, the one-parameter transversality condition is a sufficient condition to ensure that the UEP computed by the BCU method lies on the stability boundary of the (post-fault) power system. We point out that the one-parameter transversality condition is not a necessary condition and that the development of a numerical procedure to check the one-parameter transversality condition can be very involved and may be unnecessary. We propose to take another approach to verify whether the UEP computed by the BCU method lies on the stability boundary of the (post-fault) power system. To explain this approach, we first review the one-parameter transversality condition in the BCU method.
In developing a BCU method for a given power system stability model, the associated artificial, reduced-state model must be defined. To explain the reduced-state model, we consider the following generic network-preserving transient stability model,
                              0          =                                                                      ∂                  U                                                  ∂                  u                                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                1                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                0          =                                                    -                                                      ∂                    U                                                        ∂                    w                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                2                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                T                                      x              .                                =                                                    -                                                      ∂                    U                                                        ∂                    x                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                3                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                y            .                    =          z                                                                                M                                      z              .                                =                                    -              Dz                        -                                                            ∂                  U                                                  ∂                  y                                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                4                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                        (        1        )            where U(u,w,x,y) is a scalar function. Regarding the original model (1), we choose the following differential-algebraic system as the artificial, reduced-state model.
                              0          =                                                    -                                                      ∂                    U                                                        ∂                    u                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                1                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                0          =                                                    -                                                      ∂                    U                                                        ∂                    w                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                2                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                T                                      x              .                                =                                                    -                                                      ∂                    U                                                        ∂                    x                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                3                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                y            .                    =                                                    -                                                      ∂                    U                                                        ∂                    y                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                      +                                          g                4                                                          (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                        (        2        )
The fundamental ideas behind the BCU method can be explained as follows. Given a power system stability model (which admits an energy function), the BCU method first explores the special properties of the underlying model with the aim of defining an artificial, reduced-state model such that the following static as well as dynamic relationships are met.
Static Properties
                (S1) the locations of equilibrium points of the reduced-state model correspond to the locations of equilibrium points of the original model (1). For example, (û,ŵ,{circumflex over (x)},ŷ) is an equilibrium point of the reduced-state model if and only if (û,ŵ,{circumflex over (x)},ŷ,0) is an equilibrium point of the original model (1), where 0∈Rm and m is an appropriate positive integer,        (S2) the types of equilibrium points of the reduced-state model are the same as that of the original model. For example, (us,ws,xs,ys) is a stable equilibrium point of the reduced-state model if and only if (us,ws,xs,ys,0) is a stable equilibrium point of the original model. (û,ŵ,{circumflex over (x)},ŷ) is a type-k equilibrium point of the reduced-state model if and only if (û,ŵ,{circumflex over (x)},ŷ,{circumflex over (0)}) is a type-k equilibrium point of the original model.Dynamical Properties        (D1) there exists an energy function for the artificial, reduced-state model (2).        (D2) an equilibrium point, say, (û,ŵ,{circumflex over (x)},ŷ) is on the stability boundary ∂A(us,ws,xs,ys) of the reduced-state model (2) if and only if the equilibrium point (û,ŵ,{circumflex over (x)},ŷ,0) is on the stability boundary ∂A(us,ws,xs,ys,0) of the original model (1).        (D3) it is computationally feasible to efficiently detect the point at which the projected fault-on trajectory (u(t),w(t),x(t),y(t)) hit the stability boundary ∂A(us,ws,xs,ys) of the post-fault reduced-state model (2) without resorting to an iterative time-domain procedure to compute the exit point of the post-fault reduced-state model (2).
The dynamic relationship (D3) plays an important role in the development of the BCU method to circumvent the difficulty of applying an iterative time-domain procedure to compute the exit point on the original model. The BCU method then finds the controlling UEP of the artificial, reduced-state model (2) by exploring the special structure of the stability boundary and the energy function of the reduced-state model (2). Next, it relates the controlling UEP of the reduced-state model (2) to the controlling UEP of the original model (1).
Given a power system stability model, there exists a corresponding version of the BCU method. The BCU method does not directly compute the CUEP of the original model because computing the exit point of the original model, which is a key to computing the controlling UEP, requires an iterative time-domain procedure. Instead, the BCU method computes the CUEP of the original model (1) via computing the CUEP of the artificial, reduced-state model (2).
We next present some analytical results showing that, under certain conditions, the original model (1) and the artificial, reduced-state model (2) satisfy static relationships (S1) and (S2) as well as dynamic relationships (D1) and (D2). A computational scheme will be developed and incorporated into the BCU method to satisfy dynamic relationship (D3).
Theorem 1: (Static Relationship)
Let (us,ws,xs,ys) be a stable equilibrium point of the reduced-state model (2). If the following conditions are satisfied:                (1) zero is a regular value of
            ∂      4                  U                    (                              u            i                    ,                      w            i                    ,                      x            i                    ,                      y            i                          )                        ∂      u                  ∂      w                  ∂      x                  ∂      y      for all the UEP (ui,wi,xi,yi), i=1,2, . . . , k on the stability boundary ∂A(us,ws,xs,ys),                (2) the transfer conductance of reduced-state model (2) is sufficiently small,Then, (û,ŵ,{circumflex over (x)},ŷ) is a type-k equilibrium point of reduced-state model (2) if and only if (û,ŵ,{circumflex over (x)},ŷ,0) is a type-k equilibrium point of the original model (1).
Theorem 1 asserts that, under the stated conditions, the static properties (S1) and (S2) between original model (1) and the reduced-state model (2) hold.
It can be shown that there exists a numerical energy function for the reduced-state model (2). More specifically, it can be shown that for any compact set S of the state-space of model (2), there is a positive number α such that, if the transfer conductance of the model satisfies |G|<α, then there is an energy function defined on this compact set S.
To examine the dynamic property (D2), we introduce the following family of one-parametrized systems d(λ).
                                                        ɛ              1                                                  u              .                                =                                    -                                                ∂                  U                                                  ∂                  u                                                                                (                              u                ,                w                ,                x                ,                y                            )                                                                                ɛ              2                                                  w              .                                =                                    -                                                ∂                  U                                                  ∂                  w                                                                                (                              u                ,                w                ,                x                ,                y                            )                                                                                T                                      x              .                                =                                    -                                                ∂                  U                                                  ∂                  x                                                                                (                              u                ,                w                ,                x                ,                y                            )                                                                                y            .                    =                                                                      (                                      1                    -                    λ                                    )                                                z                            -                              λ                                                  y                  .                                                      =                                          -                                                      ∂                    U                                                        ∂                    y                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                                M                                      z              .                                =                                                    -                Dz                            -                                                (                                      1                    -                    λ                                    )                                                z                            -                              λ                                                  y                  .                                                      =                                          -                                                      ∂                    U                                                        ∂                    y                                                                                (                                  u                  ,                  w                  ,                  x                  ,                  y                                )                                                                        (        3        )            Theorem 1: (Dynamic Relationship)
Let (us,ws,xs,ys) be a stable equilibrium point of the reduced-state model (2). If the following conditions are satisfied,                (1) zero is a regular value of for all the UEP on the stability boundary.        (2) the transfer conductance of the reduced-state model (2) is sufficiently small,        (3) all the intersections of the stable and unstable manifolds of the equilibrium points on the stability boundary ∂A(us,ws,xs,ys,0) of the one-parameterized model d(λ) (3) satisfy the transversality condition for λ∈[0,1],then:        [1] the equilibrium point (ui,wi,xi,yi) is on the stability boundary ∂A(us,ws,xs,ys) of model (2) if and only if the equilibrium point (ui,wi,xi,yi,0) is on the stability boundary ∂A(us,ws,xs,ys,0) of model (1)        [2] the stability boundary ∂A(us,ws,xs,ys) of model (2) is the union of the stable manifold of all the equilibrium points (ui,wi,xi,yi), i=1, 2, . . . , on the stability boundary ∂A(us,ws,xs,ys); i.e.∂A(us,ws,xs,ys)=∪Ws(ui,wi,xi,yi)  (4)        [3] the stability boundary ∂A(us,ws,xs,ys,0) of model (1) is the union of the stable manifold of all the equilibrium points (ui,wi,xi,yi,0), i=1, 2, . . . , on the stability boundary ∂A(us,ws,xs,ys,0); i.e.∂A(us,ws,xs,ys,0)=∪Ws(ui,wi,xi,yi,0)  (5)
Theorem 1 asserts that, under the stated conditions, conditions (1)-(3), the dynamic property (D2) is satisfied. Furthermore, the stability boundaries of both models are completely characterized. Condition (1) is a generic property while conditions (2) and (3) are not. We will present an approach to check the dynamic property (D2) without checking conditions (2) and (3).
A Conceptual Network-preserving BCU Method
Theorem 1 and Theorem 1 provide the theoretical basis for finding the controlling UEP of the original network-preserving model (1) via the controlling UEP of the artificial, reduced-state model (2). A conceptual BCU method for the network-preserving model is presented in the following:                A conceptual BCU method for the network-preserving model        Step 1. From the (sustained) fault-on trajectory (u(t),w(t),x(t),y(t),z(t)) of the network-preserving model (1), detect the exit point (u*,w*,x*,y*) at which the projected trajectory (u(t),w(t),x(t),y(t)) of the network-preserving model exits the stability boundary of the post-fault reduced-state model (2).        Step 2. Use the point (u*,w*,x*,y*) as the initial condition and integrate the post-fault reduced-state model (2) to find the UEP whose stable manifold contains the exit point (u*,w*,x*,y*).        Step 3. The controlling UEP with respect to the fault-on trajectory of the network-preserving model (1) is (uco*, wco*, xco*, yco*,0)
The essence of the BCU method is to compute the controlling UEP of the original model (1) via computing the controlling UEP of the reduced-state model (2) whose controlling UEP can be effectively computed. Step 1 and Step 2 of the conceptual BCU method find the controlling UEP of the reduced-state model (i.e. the controlling UEP of the projected fault-on trajectory). Step 3 relates the controlling UEP of the reduced-state model (2) to the controlling UEP of the original model (1). BCU method does not perform its calculation of CUEP in the state-space of the underlying original power system transient stability model. This is because the task of computing the exit point of the original model, which is a key to computing CUEP, requires an iterative time-domain procedure. Instead, BCU method computes the CUEP of the original model via computing the CUEP of an artificial reduced-state model. As such, BCU method computes CUEP with varying degree of success. The UEP computed by the BCU method may not always be the CUEP.
The one-parameter transversality conditions play an important role in the theoretical foundation of the conceptual BCU method. The violation of the one-parameter transversality conditions may cause incorrectness in the BCU method when computing the controlling UEP. However, due to the complexity of practical power system models, the one-parameter transversality conditions may not be always satisfied. There are several counter-examples which show the BCU method may fail to give correct stability assessments.
Based on the above analysis, we will take a different approach. Instead of checking the one-parameter transversality condition and the small-transfer-conductance condition, we propose to directly check whether or not the UEP (uco*,wco*,xco*,yco,0) lies on the stability boundary of the original model; i.e. check the dynamic property (D2) directly. We will also term the dynamic property (D2) the boundary property.
It can be shown that the boundary property holds for high damping systems while it may not hold for low damping systems. The issue of how to determine the critical damping value above which the boundary property holds remains open. The critical damping value seems to depend on a variety of factors including network topology, loading condition, and system models used, among others.
Damping Terms and Boundary Property
It has been shown that under the one-parameter transversality condition, BCU method can compute exact CUEP. However, the verification of one-parameter transversality condition is not an easy task either. At the present time, with the development of improved BCU classifiers, the only factor that degrades the reliability of the BCU method (i.e. BCU method gives incorrect stability assessments) is that the unstable equilibrium point (UEP) computed by the BCU method may not always be the true (correct) controlling UEP. Furthermore, UEPs computed by BCU method may not even satisfy the boundary condition. We say a computed UEP (with respect to a contingency) is said to satisfy the boundary condition if the computed UEP lies on the stability boundary of the original post-contingency system.
This factor can clearly explain the reason why the BCU method may give incorrect stability assessments for certain types of contingencies. BCU method fails because of the violation of the boundary condition due to insufficient system damping. Technically speaking, insufficient system damping leads to the occurrence of global bifurcation in the parameterized dynamical systems underlying the BCU method. On the other hand, it has been found that the BCU method performs very well if the boundary condition is satisfied; in addition, the boundary condition is satisfied if the system damping terms are sufficiently large.
The BCU method may give incorrect stability assessments for certain types of contingencies (cases). For illustrative purpose, we will present numerical results in which the BCU method fails to give correct stability assessments for some cases, due to either multi-swing phenomenon or light damping. In all cases, the BCU method fails because of the violation of boundary property. It will be shown that the BCU method works well if the boundary property is satisfied; furthermore, the boundary property is satisfied if the system damping terms are sufficiently large.
Some Numerical Examples
We apply the BCU method to analyze a contingency list of a test system. We present some cases in which the BCU method fails and point out the reasons why this failure occurs.
Table 1 displays some cases in which the BCU method fails to give correct stability assessments. We point out that these cases all exhibit multi-swing phenomena and the boundary properties are not satisfied. All the cases listed in Table 1 belong the same group; group #4. We also present some cases in which the BCU method works well in Table 2. It should be pointed out that all the cases in Table 2 belong to two groups of coherent contingencies, group #13 and group #43, and they all satisfy the boundary condition.
TABLE 1A group of coherent contingencies which the BCU Method Fails.FaultTime-BoundaryFaultClearingBCUBCUDomainMode ofDistance/BoundaryDescriptionTime(s)MarginAssessmentAssessmentInstabilityUEP GroupPropertyFault Bus 5360.071.1127StableStableMulti-swing0.234/4NoOpen line0.100.983StableUnstable0.234/4No536-537Fault Bus 7070.071.17StableStableMulti-swing0.234/4NoOpen line0.100.9433StableUnstable0.234/4No707-708Fault Bus 5210.050.3587StableUnstableMulti-swing0.232/4NoOpen line0.070.2387StableUnstable0.232/4No521-522Fault Bus 520.051.0874StableUnstableMulti-swing0.200/4NoOpen line0.070.8627StableUnstable0.200/4No52-575
TABLE 2A group of coherent contingencies which the BCU Method Succeeds.FaultTime-BoundaryClearingBCUBCUDomainMode ofDistance/BoundaryFault DescriptionTime(s)MarginAssessmentAssessmentInstabilityUEP GroupPropertyFault Bus 7090.070.948StableStableSingle-swing1.0/43YesOpen line 104-7090.10−0.225UnstableUnstable1.0/43YesFault Bus 380.070.468StableStableMulti-swing1.0/13YesOpen line 38-550.10−0.551UnstableUnstable1.0/13Yes
TABLE 3A group of coherent contingencies which the BCU Method Fails.FaultTime-BoundaryFaultClearingBCUBCUDomainMode ofDistance/BoundaryDescriptionTime(s)MarginAssessmentAssessmentInstabilityUEP GroupPropertyFault Bus 30360.050.0211StableUnstableMulti-swing0.200/27NoOpen line0.07−0.0695UnstableUnstable0.200/27No3036-3037Fault Bus 40210.051.9706StableUnstableMulti-swing0.310/39NoOpen line0.071.9420StableUnstable0.310/39No4021-4022Fault Bus 40290.070.5595StableUnstableMulti-swing0.289/35NoOpen line0.27−0.3527UnstableUnstable0.289/35No4026-4029Fault Bus 1070.070.4302StableUnstableMulti-swing0.234/52NoOpen line 107-41240.15−0.1049UnstableUnstable0.234/52NoThe Damping Factors
We have observed that the reliability of BCU method in stability assessments increases (i.e., it works on more number of contingencies) as the system damping factors become larger. For example, while BCU method fails on contingencies as listed in Table 3 due to small damping, the method works on some of these contingencies, in particular on the group #52 if the system damping factor increases, as shown in Table 4. It can be seen from this table that the boundary distance becomes closer to 1.0; in other words, the computed CUEP becomes closer to the stability boundary of the original system. Furthermore, the time-domain behaviors of the study power system subject to these contingencies improve; more specifically, the transient stability is enhanced.
As we further increase the damping effect, the reliability of the BCU method is further improved. Table 5 lists the performance of the BCU method for the same cases as those in Table 4, except that the system damping factors are doubled. BCU method computes CUEPs satisfying the boundary property for these contingencies in groups #27, #39 and #52 of coherent contingencies. In addition, the boundary distance of the computed UEP relative to each contingency in group #35 all lies closer to 1.0. These results clearly show that as the system damping factor increases, the boundary distance of the computed CUEP by the BCU method increases and the satisfiablity of boundary condition relative to contingencies by the BCU method also increases. Furthermore, the transient stability of the study power system subject to these contingencies is enhanced.
TABLE 4BCU method works for group #52 when damping is increased.FaultTime-BoundaryClearingBCUBCUDomainMode ofDistance/BoundaryFault DescriptionTime(s)MarginAssessmentAssessmentInstabilityUEP GroupPropertyFault Bus 30360.070.177StableStableMulti-swing0.701/27NoOpen line0.17−0.303UnstableUnstable0.701/27No3036-3037Fault Bus 40210.072.727StableStableMulti-swing0.824/39NoOpen line0.77−0.157UnstableUnstable0.824/39No4021-4022Fault Bus 40290.070.563StableStableMulti-swing0.867/35NoOpen line0.37−0.048UnstableUnstable0.867/35No4026-4029Fault Bus 1070.071.081StableStableMulti-swing 1.00/52YesOpen line0.30−0.245UnstableUnstable 1.00/52Yes107-4124
TABLE 5BCU method works for groups #27, #39 and #52 when damping is increased.FaultTime-BoundaryClearingBCUBCUDomainMode ofDistance/BoundaryFault DescriptionTime(s)MarginAssessmentAssessmentInstabilityUEP GroupPropertyFault Bus 30360.070.934StableStableMulti-swing1.00/27YesOpen line0.170.525StableStable1.00/27Yes3036-3037Fault Bus 40210.072.813StableStableMulti-swing1.00/39YesOpen line0.771.750StableStable1.00/39Yes4021-4022Fault Bus 40290.070.588StableStableMulti-swing0.948/35 NoOpen line0.370.279StableStable0.948/35 No4026-4029Fault Bus 1070.071.182StableStableMulti-swing1.00/52YesOpen line0.300.306StableStable1.00/52Yes107-4124
From the viewpoint of state space, the increase of the boundary distance of the computed UEP due to the increase of the system damping clearly demonstrates the effect of damping terms on transient stability; it enhances the transient stability by enlarging the stability region of the post-fault SEP, hence it increases the critical clearing times as well as the energy margin.
These observations will lead to the development of a group-based BCU method in which the boundary property will be checked. In order to develop schemes for an efficient check of the boundary property, the concept of a group of coherent contingencies will be proposed and explored. Several group properties will be explored and investigated. These group properties will be taken into the development of the group-based BCU method. The group-based BCU method will also include a scheme to compute the critical energy for those contingencies in which the boundary property is not satisfied.
With the introduction of a boundary property, one can check the correctness of a computed CUEP, say by the BCU method, through checking its boundary property; instead of checking the one-parameter transversality condition which is very difficult to check. By computing the boundary distance of the computed CUEP, one can verify whether or not the computed CUEP lies on the stability boundary of the original system; if the boundary of the computed CUEP is 1.0, then the CUEP lies on the stability boundary of the original post-fault system; otherwise, it is not.
It will be shown that the boundary property is a group property (a group property is a property which holds for every member in the group); hence it is not necessary to compute the boundary distance for each computed UEP in each group of coherent contingencies. Computing the boundary distance of a UEP in a group of coherent contingencies is sufficient to determine the boundary property of all of the contingencies in the group. The exploration of the group property will lead to a significant reduction in computation, as will be explained later.
We will describe in this invention a novel system, called Group-based BCU-DSA, for on-line dynamic security assessments and energy margin calculations of practical power systems in modern energy management systems. The novel system meets the requirements of on-line dynamic security assessment and energy margin calculations through effective exploration of the merits of both the group-based BCU method (and the improved BCU classifiers) and the detailed time-domain simulation program. There are three major components in this architecture: (i) a sequence of improved BCU classifiers whose major functions are to screen out, from a set of credible contingencies, all of those contingencies which are definitely stable and to capture all of the (potentially) unstable contingencies, (ii) a BCU-guided time-domain program for stability analysis and energy margin calculation of both the (potentially) unstable and undecided contingencies captured by the sequence of improved BCU classifiers in (i), and (iii) a group-based BCU method.

Group-based BCU methods for on-line dynamical security assessments and energy margin calculations of practical power systems

The Tokyo Electric Power Company, Incorporated


Disclosed is a current sensor that senses current flow in a conductor by coupling a first magnetic field generated by the conductor to a sense element. The current sensor includes a shield including a first material that sandwiches the sense element to define a stack and a second material that sandwiches the stack. The shield is configured to generate a second magnetic field, responsive to a third magnetic field external to the current sensor that opposes the third magnetic field. The shield is further configured to prevent production of a magnetic field that opposes the first magnetic field generated by the flow of current in the conductor.

Accurate current measurement can be important in electronic systems. For example, in a wireless power transfer system, accurate measurement of the current injected into the antenna coil of a power transmit unit (PTU) may be used to maintain proper levels of electromagnetic (EM) radiation into the environment. Some solutions may be based on measuring the voltage drop across two series capacitors, one capacitor attached to each of the coil leads of the antenna. Measuring the voltage directly can create technical challenges related to the design of the differential voltage buffer and amplifier circuits because both coil leads are at a high voltage. In addition, the measurement process can be complex, requiring the measurement of the voltage across the antenna coil behind the series capacitors and then measuring the voltage after the series capacitors, along with fast switching of voltages that feed into low pass filters. The approach has some disadvantages: the circuitry may require costly components to implement; and the process of taking measurements can create a good amount of electromagnetic interference (EMI) due to switching noise which can be injected into the antenna.

Apparatus and method for a current sensor


An electrophotographic image forming apparatus capable of reliably forming an image with density gradation, one which does not have a low-quality appearance. The estimated average halftone granularity of the toner image after developing but before electrostatic transfer was set at 0.25 or less. The average halftone granularity was found by measuring the granularity of a toner image at locations of different average brightness by means of newly proposed formula, and averaging the measured values for which the average brightness is 40 to 80. The estimated average halftone granularity was obtained by estimating the average halftone granularity of the toner image on a photoreceptor by means of a newly proposed method.

1. Field of the Invention
The present invention relates to an image forming method for forming an image by electrophotography, and to a copier, facsimile device, printer, or other such image forming apparatus that makes use of this method.
2. Description of the Related Art
Conventional image forming methods for forming an image by electrophotography have been disclosed, for example, in Japanese Laid-Open Patent Applications 2002-202638 and 2002-287545. With these image forming methods, first a latent image is formed by an exposure apparatus on a latent image support such as a photoreceptor, after which this latent image is developed and made visible by causing toner to adhere electrostatically thereto. Next, this developed toner image is electrostatically transferred onto transfer paper or another such recording medium, then a fixing roller or other such heating member is brought into close contact to heat this toner and fix it to the recording medium.
One advantage to an electrophotographic image forming method such as this is that an image can be easily formed on the basis of electronic image information, but a disadvantage is that image quality is inevitably inferior to that produced by offset printing. In particular, with images having density gradation, such as photographs or pictures, the roughness is much more pronounced than with offset printing, and tends to give the viewer an impression of lower quality. Consequently, an important question with electrophotography is how to minimize this appearance of lower quality.
RMS granularity, which has been standardized in ANSI PH-2.40-1985 is known as an index of the roughness of an image, and this is calculated from the following Eq. 1.RMS granularity σD=[(1/N)×Σ(Di−D)2]1/2  Eq. (1)
Here, N is the number of data, Di is the density distribution, and D is the average density (D=1/NΣDi).
Also, granularity GS defined by Dooley and Shaw of Xerox is another known index of roughness. This is the numerical value obtained by integrating the cascade values of a visual spatial-frequency characteristic (visual transfer function (VTF)) and the Wiener Spectrum (hereinafter referred to as WS(f)). WS(f) is the squared ensemble average of a Fourier spectrum obtained by the Fourier transformation of a density fluctuation from an average density obtained by scanning an image with a microdensitometer. The granularity GS is calculated from the following Eq. 2 (for details, see Dooley and Shaw: "Noise perception in Electrophotography," J. Appl. Photogr. Eng., Vol. 5, No. 4, (1979), pp. 190-196).granularity GS=exp(−1.8D)∫(WS(f))1/2VTF(f)df  Eq. 2
Here, D is the average density, f is the spatial frequency (c/mm), and VTF(f) is the visual spatial-frequency characteristic.
However, of the images printed out by a given image forming apparatus, some have relatively good RMS granularity σD and granularity GS, while others do not. It is therefore difficult to evaluate the performance of an image forming apparatus on the basis of the RMS granularity σD and granularity GS of a printed image. Furthermore, up to now there had yet to be adequate study into what kind of images do not have a grainy look. Plus, none of the electrophotographic image forming apparatuses on the market today allow for the reliable formation of images that do not have a low-quality appearance.

Image forming method and image forming apparatus for same


A system for heating two independent water supplies having a water storage tank adapted to contain a first, potable water supply and a coiled heat exchange tube mounted within the tank to contain and conduct a second, non-potable water supply. The tank has a top, bottom, wall, and flue communicating between the top and bottom. The tube is in communication with the exterior of the tank and with a circulatory space heating system. The tube has a double wall to protect against the mixing of the potable and non-potable water supplies, and the ends of the tube terminate at the surface of the water storage tank at a dielectric fitting which maintains electrical isolation between dissimilar metals otherwise exposed to the water.

This invention relates to a combined water heating system For domestic or commercial use which is capable of heating water for consumption as well as for space heating. The system heats potable water for consumption while exchanging heat to a recycling water-based space heating system. The combined water heating system provides this function while maintaining separation between the potable and non-potable water supplies.

Combined water heater and heat exchanger


A solid-state imaging device includes a first substrate, a second substrate, connection units that electrically connect the first substrate aid the second substrate, pixels in the first substrate, the pixel including a photoelectric conversion element that converts incident lights to signal charges and accumulates the signal charges, and the pixel outputting pixel signals in accordance with the signal charges, signal lines that supply the second substrate with the pixel signals via the connection units, signal integration units in the second substrate that integrate the pixel signals supplied via the signal lines, and that produce an integrated signal, and signal output units that output the integrated signal.

1. Field of the Invention
The present invention relates to a solid-state imaging device, a method for controlling a solid-state imaging device, and an imaging device.
Priority is claimed on Japanese Patent Application No. 2012-114446, filed May 18, 2012, the content of which is incorporated herein by reference.
2. Description of Related Art
In recent years, CMOS (Complementary Metal Oxide Semiconductor)-type solid-state imaging devices (hereinafter, referred to as "MOS-type solid-state imaging devices") have attracted attention as a solid-state imaging device and have been put to practical use.
Such MOS-type solid-state imaging device can be driven with a single power supply unlike CM (Charge Coupled Device)-type solid-state imaging devices. In addition, a CCD-type solid-state imaging device requires dedicated manufacturing processes, whereas the MOS-type solid-state imaging device can be manufactured using the same manufacturing processes as those of other LSIs. For this reason, the MOS-type solid-state imaging device easily deals with an SOC (System On Chip), and can realize the multi-functionalization of the solid-state imaging device.
In addition, the MOS-type solid-state imaging device includes an amplifying circuit in each pixel and thus amplifies signal charges within the pixel. For this reason, the MOS-type solid-state imaging device has a configuration which is hardly influenced by noise from a signal transmission path. Further, the MOS-type solid-state imaging device is characterized in that the signal charge of each pixel can be selected and extracted (selection scheme), and the accumulation time or the reading order of signals can be freely controlled for each pixel in principle.
Previously, as exposure types of general MOS-type solid-state imaging devices (hereinafter, also referred to as a "solid-state imaging devices"), a line exposure type and a global exposure type have been known. In the line exposure type, a large number of pixels arrayed two-dimensionally within the solid-state imaging device are exposed at a timing which is different for each row. The line exposure type is a type in which a video signal of a subject is obtained by sequentially reading signal charges generated after performing exposure of a row of a certain unit by the photoelectric conversion element within pixels in the row. In the case of the line exposure type, exposure and reading can be continuously performed in row units. For this reason, it is possible to obtain a video signal of a subject in a state in which the influence of noise generated in an accumulation section that accumulates the signal charge generated by the photoelectric conversion element is suppressed to a minimum. However, when an image of a moving subject is captured in the line exposure type, an image of the subject cannot be correctly captured due to the exposure timing different for each row. Particularly in the line exposure type, there is a problem that the distorted video of the subject is obtained depending on the direction in which the subject moves.
On the other hand, the global exposure type is a type in which all the pixels arrayed two-dimensionally within the solid-state imaging device are exposed at a synchronous timing. In the case of the global exposure type, since all the pixels are exposed at a synchronous timing, there is no problem in that a distorted video is obtained even at the time of capturing an image of the moving subject. However, in the global exposure type, since the signal charge generated by the photoelectric conversion element within the pixel is sequentially read after all of the pixels are exposed, it is difficult to suppress the influence of noise generated in the accumulation unit in the pixels that require a long time until the reading of the signal charge is started after terminating exposure. For this reason, in the global exposure-type solid-state imaging device, a video signal having a large amount of noise is obtained more often than in the line exposure-type solid-state imaging device.
In the global exposure-type solid-state imaging device, a circuit for suppressing the influence of noise generated in the accumulation unit as mentioned above is added to the solid-state imaging device, thereby allowing a video signal to be obtained in which the influence of noise is suppressed to a minimum even in the solid-state imaging device in which the global exposure type is adopted. However, the addition of the circuit which suppresses the influence of noise to the solid-state imaging devise causes problems that the total area of the solid-state imaging devise becomes enlarged and the solid-state imaging devise itself becomes enlarged.
As a technique for solving such problems, for example, Japanese Unexamined Patent Application, First Publication No. 2006-49361 discloses a method of which creating a pixel circuit unit of a MOS-type solid-state imaging device as a pixel circuit chip, whereas creating a signal processing unit as a signal processing chip, and superimposing the chips which are separately created. In the art disclosed in Japanese Unexamined Patent Application, First Publication No. 200649361, the pixel circuit chip and the signal processing chip which are separately created are connected to each other through a bump.
On the other hand, if a picture in a dark place, or a picture of a subject having low illuminance, for example, is taken by the MOS-type solid-state imaging device, the long-time exposure may be performed in order to supply sufficient light quantity to the MOS-type solid-state imaging device. However, if the long-time exposure is performed, the temperature of the MOS-type solid-state imaging device increases, thus, the image deteriorates due to the influence of pixel defects caused by dark currents. Therefore, the correction of the pixel detects caused by dark currents is performed by an image processing later.
Moreover, in the MOS-type solid-state imaging device which includes the chips pasted together as disclosed in Japanese Unexamined Patent Application. First Publication No. 2006-49361, it is often the case that a substrate including photoelectric conversion units (pixel circuit chips) is a backside illumination (BSI) type. Since the substrate including the photoelectric conversion units is the backside illumination type, it is possible to supply a lot of light quantity to the photoelectric conversion units. However, in the backside illumination type, the crosstalk of the charges is large due to its configuration. Therefore, in the MOS-type solid-state image sensor of the backside illumination type, if pixel defects caused by dark currents exist, the defects are enlarged by leaking the charges of the pixel defects to the surrounding pixels in the long-time exposure. and it resulted in the large detects. Since it is difficult to correct these large defects by the image processing later, there is a problem of an increase in image degradation.

Solid-state imaging device, method for controlling solid-state imaging device, and imaging device


A method for Ethernet virtualization using assisted frame correction. The method comprises receiving at a host adapter data packets from a network, storing the received data packets in host memory, storing the received data packets in a hardware queue located on the host adapter, setting a status indicator reflecting the status of the data packets based on results of the checking, and sending the status indicator to the host memory.

This invention relates generally to network virtualization and, more particularly, to methods, systems, computer program products, and hardware products for implementing Ethernet virtualization.
Current LAN/WAN networks are becoming increasingly more complicated. LAN performance is increasing exponentially as network applications continue to generate large amounts of network traffic. In addition, there is a need to decrease response times. Each transaction is becoming more reliant on the underlying infrastructure. More traffic increases the frequency of LAN errors, both with the transport protocol and with the underlying physical medium.

International Business Machines Corporation


A surveillance system (10) for monitoring movement in a region of interest (18) is described. The surveillance system (10) includes: An image capturing system (12) having a field of view (16) including a region of interest (18), and adapted to capture an image of the region of interest (18). An image processing system (78) configured to process a time-sequential series of images of the field of view from the image capturing system such that at least a portion (52, 53, 54) of each processed image (50) is analyzed for detecting movement within the region of interest (18). The image capturing system (12) is configured to capture, in each image, different apparent magnifications of respective zones (20, 22, 24) within the region of interest (18) in the field of view (16) that are at different distances from the image capturing system (12) such that an object (60) in at least one position in at least two of said zones has substantially the same apparent size in the images.

Video Motion Detection (VMD) may be used for surveillance applications such as for perimeter protection and intrusion detection. It uses a computer to analyse a video sequence of the perimeter of a property, and provides notification which may include an alarm, if an intruder appears in the scene. Typically, such a system will operate in the near field, covering an area from a few meters in front of the camera to 30 meters away. The image has enough resolution to readily distinguish subjects in the near field, and barely sufficient resolution to distinguish objects at 30 meters or more.
To resolve objects that are further away, higher resolution cameras may be used to capture an image at a higher optical resolution. While the resolution of an image may be improved by software after the image has been captured, the end resolution is ultimately limited by the optical resolution at which the image is captured, which is a function of the camera optics and the image sensor that captures the image. For a given optical magnification of an image, an increase in optical resolution requires a more expensive image sensor, having an increase in sensor density and a corresponding increase in data. Similarly, an increase would occur if the end resolution were increased by software. The increase in data takes more processing to compress, send, and analyse. As a result, the rate at which video frames can be processed on modest hardware drops as the resolution increases. In security applications, since it is desirable to sense vehicles or fast running intruders that quickly cross the field of view; a high frame rate is desirable. This means that only low or medium resolution images can be analysed quickly enough on modest hardware to be useful in security applications.
Long range VMD can be effected by using a telephoto lens on the camera. However, the short range coverage is sacrificed to achieve this due to the narrow field of view of a telephoto lens. Furthermore, it is easy for an intruder in the foreground to obscure the view of the camera without the identity of the intruder or nature of the obscuration being evident from the video.
Long range Passive Infrared (PIR) devices have been developed to detect intruders over a range from a few meters to 150 meters away. PIR detectors have a pair of sensors that measure an intensity level of infrared radiation, and based on the shift in intensity level from one sensor to the other, determine whether moving infrared radiation is present and if an alarm condition is met. These detectors are very effective at detecting moving infrared radiation at the different ranges, but as the detection is of a pair of intensity levels only, the PIR does not know the shape of the object that causes a shift in intensity levels. Therefore, PIR alone can false alarm on animals such as foxes, rabbits and deer, and a typical installation requires a camera capable of zooming in on the area that causes an alarm to verify that the alarm condition is correct.
PIR detectors may be complemented with video cameras to allow video verification. Installing a PIR and a video camera with zoom capability as a complementary pair suffers from alignment issues since the PIR and the camera need to point at the same zones so that an operator can verify a PIR alarm quickly. In practice, it is difficult for an installer to align the two sensors. As a result, it is possible for a PIR alarm to be triggered in an area that the camera cannot see. U.S. Pat. No. 5,936,666 describes the collocation of two sensors in the same enclosure to overcome the issue of alignment of the fields of view of the two sensors during installation.
It is an object of the invention to at least in part alleviate one or more of the above-described limitations with known surveillance systems that rely on VMD and/or PIR devices.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art.


A method of optical proximity correction (OPC) includes the following steps. First, a layout pattern is provided to a computer system. Subsequently, the layout pattern is classified into a first sub-layout pattern and a second sub-layout pattern. Then, an OPC calculation based on a first OPC model is performed on the first sub-layout pattern so as to form a corrected first sub-layout pattern and an OPC calculation based on a second OPC model is performed on the second sub-layout pattern so as to form a corrected second sub-layout pattern. Afterward, the corrected first sub-layout pattern and the corrected second sub-layout pattern are output from the computer system into a photomask.

1. Field of the Invention
The present invention generally relates to a method of optical proximity correction (OPC), and more particularly, to a method of OPC which comprises more than one OPC model.
2. Description of the Prior Art
With the trend of miniaturization of the electronic products and peripherals, research about thin structures and high integration of the semiconductor devices have become the essential subjects and developing aspects in the industry, and the lithography technology plays an important role to determine the performances of the semiconductor devices.
In semiconductor manufacturing processes, the integrated circuit layout is first designed and formed as a mask pattern. The mask pattern is then proportionally transferred to a photoresist layer disposed on the semiconductor wafer through an exposure process followed by a development process. Subsequently, a corresponding etching process is performed in order to manufacture the semiconductor devices on the semiconductor wafer. With the demand of increasing integration and the decreasing size of the semiconductor devices, the critical dimension (CD) of each segment fabricated through exposure is limited to the resolution limit of the optical exposure tool used for transferring the mask pattern. The optical proximity effect is a problem that easily arises during the exposures of a mask pattern with high-density arranged segments to form a pattern on a photoresist. Such a resolution loss occurs because of overexposure or underexposure, which brings a deviation of the pattern on the photoresist layer from the original mask pattern. Many methods have been used to avoid the deviation caused by the optical proximity effect in order to improve the quality of the transferred pattern. The most popular method is the optical proximity correction (OPC). And there is a variety of commercial optical proximity correction software that can theoretically correct the mask patterns to be more accurately transferred on a wafer.
Currently, a modeled-based optical proximity correction method, which uses optical proximity correction models to simulate the final mask pattern needed to be transferred to the corresponding photoresist layer, is widely used in processes for manufacturing semiconductor devices. Generally, various optical proximity correction models are provided in order to fulfill the needs of various mask patterns. For example, when an original layout pattern corresponding to a M0 structure of a semiconductor device needs to be formed in a semiconductor device, this pattern must be simulated by an optical proximity correction (OPC) method based on a proper optical proximity correction model in order to output a corrected pattern (i.e. a corrected M0 pattern) into a photomask. However, the OPC method, which is based on only one kind of OPC model, can not fulfill the needs of the M0 pattern including different geometric patterns with various length-to-width ratios. Accordingly, some patterns transferred from the photomask to a photoresist layer with a relatively high length-to-width ratio would still collapse even though the optical proximity correction method is applied. Consequently, how to improve the method of optical proximity correction to form the needed mask pattern is still an important issue in the field.


Apparatus and methods for supplying a gas to a processing chamber are described. The apparatus comprises an inlet line and an outlet line, each with two valves, in fluid communication an ampoule. A bypass line connects the inlet valve and outlet valve closest to the ampoule. The apparatus and methods of use allow a precursor residue to be removed from the delivery lines of a processing chamber.

Metal-organic (MO) precursor vapor is commonly used for the thermal deposition of metal films inside a well-controlled processing chamber. Metal-organic precursors are usually in liquid or solid form. Metal-organic vapor is usually generated thermally inside a closed vessel or ampoule. Molecules of the MO precursor are then delivered to a wafer surface inside the processing chamber through a delivery gasline. In order to prevent the vapor reverting back to its bulk form, the delivery gasline is usually thermally controlled to be well above the dew point of the particular MO precursor.
In order to have efficient delivery, an inert gas is usually used to carry the precursor vapor along the delivery line. The purpose of this carrier gas is mainly two-fold: (1) to increase the vapor pressure of the precursor due to agitation of gas flow into the vessel; and (2) to dilute the precursor inside the delivery line to raise the thermal decomposition temperature of the precursor.
After the deposition process reaches a predetermined thickness, an ampoule outlet pneumatic valve is closed; leaving the delivery line with a substantial amount of unused precursor vapor. This unused vapor should be quickly removed to preserve the well-controlled process performance. If not removed quickly, the residual precursor can accumulate to form various particulates which may contaminate the deposited film.
Most metal-organic chemical vapor deposition (MOCVD) processes of metal films are deposited using synthesized metastable chemicals as the precursors. Some of metal-organic precursors decompose readily at very low temperature. In order to achieve well-controlled process performance—such as precise thickness and low particle contamination—management of the residual precursor vapor in the delivery line post-deposition can be important. If the residual precursor is not removed promptly, it will be added to the subsequent deposition process. The residue can accumulate to form particles, which will be pushed onto wafer surface. Therefore, there is a need in the art for apparatus and methods to provide improved removal of residual precursor.

Apparatus and methods to remove residual precursor inside gas lines post-deposition


An operating device includes a handle, a sensor system and an actuator. The handle is configured to be: manually deflectable from an inoperative position relative to an axis, and rotatable about the axis, and/or displaceable axially with respect to the axis, and/or tiltable in relation to the axis, and/or displaceable transversely with respect to the axis. The sensor system is configured to detect the deflection of the handle and has a haptics device by which the handle can be subjected to the action of a haptically detectable effect in correspondence with the deflection of the handle. The actuator, to which the handle is fixedly connected, is configured to drive the handle such that the actuator can be moved alternately in one degree of freedom by a movement distance of <1 mm depending on the deflection of the handle.

1. Field of the Invention
The invention relates to an operating device having a handle that can be manually deflected from an inoperative position relative to an axis, wherein the handle can be rotated about the axis and/or can be displaced axially with respect to the axis and/or can be tilted in relation to the axis and/or can be displaced transversely with respect to the axis, having a sensor system for detecting the deflection of the handle and having a haptics device by which the handle can be subjected to the action of a haptically detectable effect depending on the deflection of the handle.
2. Related Art
Operating devices of this kind are used in motor vehicles in order to control the various vehicle functionalities. In this case, the handle can be deflected with two or more types of deflection, and therefore a relatively large selection of vehicle functionalities can be actuated.


In a network containing a macro base station and wireless access points within the range of the macro base station, information from wireless access points are used to change the quantity of almost blank subframes delivered by the macro base station, adjust the cell range extension area of one or more of the wireless access points, or provide instructions to alter the number of wireless access points. The information is analyzed. The analysis allows determination of a capacity gain associated with using the wireless access points within an area associated with the macro base station and whether the capacity gain provides at least a threshold amount of gain permitting the macro base station and the wireless access points to provide service to mobile devices within the area.

A cellular phone carrier may use a macro base station to handle traffic and signaling between mobile devices and a core of a cellular phone network. To accommodate additional traffic, a cellular phone carrier may use one or more small cells (e.g., a micro cell), in addition to the macro base station, to increase the capacity of the cellular phone network to accommodate the additional traffic.


The invention relates to a device for carrying out examinations of the human eye, comprising a diagnostic unit, which when examinations are carried out is arranged in front of the left or the right eye, and comprising a frame which comprises an upper part and a lower part, wherein the lower part is arranged so as to be stationary, and wherein the upper part carries the diagnostic unit, and for positioning the diagnostic unit in front of the left or the right eye can be adjusted in the X-direction relative to the lower part, wherein the device comprises at least one sensor system with which the position of the upper part can be measured in the X-direction relative to the lower part.

Generically, the device provides for a diagnostic unit, for example a keratometer or pachymeter by means of which the eye examination is carried out. For the actual examination, the diagnostic unit must be arranged in front of the eye that is being examined. To enable the treating physician to investigate either the left or the right eye of a patient, generic devices provide for a frame in which the upper part is adjustable in at least one direction relative to the lower part. This direction (X-direction) is such that the diagnostic unit which is attached to the upper part of the frame can either be arranged in front of the left or the right eye of the patient.
The known devices are associated with a disadvantage in that the allocation which shows whether the examination result refers to the left or the right eye has to be determined by the treating physician examining it and documenting it manually, for example by writing it down. This type of determination and documentation of the allocation of the examination results is not only relatively time consuming but also very susceptible to errors occurring. If the allocation of the examination results in relation to the left or the right eye is incorrectly documented, this can lead to extremely grave treatment errors. For example, treatment which is necessary on one eye might inadvertently be carried out on the other eye, namely the healthy eye.

Device for carrying out examinations of the human eye


A molding unit mainly includes a molding body which has a covering portion, and a complemental covering member which is positioned longitudinary along the molding body and which has a complemental covering portion. When the molding body with the complemental covering member is positioned along a window shield of an automobile, the outside surface of the window shield is seated by the covering portion of the molding body at one portion thereof and is seated by the complemental covering portion of the complemental covering member at the other portion thereof.

The present invention relates to a molding unit for use with an automobile, and more particularly, the invention relates to a molding unit which can perfectly seal a clearance between the window shield and the body and which can be used even when the gap height between the outside surface of the window shield and the outside surface of the body is not uniform throughout the overall circumferential length of the window shield.
The conventional molding unit for use with an automobile generally comprises a strip formed of rubber or synthetic resin adapted to be positioned on the circumferential edge of the window shield and adapted to be mounted on the body by an adhesive or a double-sided tape, and a molding body adapted to be inserted in a clearance between the circumferential edge of the window shield and the body and adapted to be engaged with the strip so as to be fixedly connected to the body.
Such a conventional molding unit is found, for example, in Japanese Laid-Open Utility Model Publication Nos. 63-32915 and 63-32916. Japanese Publication No. 63-32915 discloses a molding body having a weir portion to downwardly lead rainwater which is formed by partly cutting off the molding body. Japanese Publication No. 63-32916 discloses a molding body having a weir member to downwardly lead rainwater which is longitudinarily bonded to the molding body.
A problem usually associated with the molding unit in the prior art as described in Japanese Publication No. 63-32915 is that the cutting operation of the molding body causes burrs on the molding body. This may lead to undesirable awkward appearance.
Another problem usually associated with the molding unit in the prior art as described in Japanese Publication No. 63-32916 is that the weir member is independently formed and is bonded to the molding body. This may also lead to undesirable awkward appearance.
A further problem usually associated with the molding unit in the prior art as described in Japanese Publications Nos. 63-32915 and 63-32916 is that such a molding unit is not adaptable when the gap height between the outside surface of the window shield and the outside surface of the body is not uniform throughout the overall circumferential length of the window shield.


A method of determining sulfur loading of an organic polysulfide composition comprises reacting the organic polysulfide composition with an organic phosphine to produce reaction products comprising organic phosphine sulfide and an organic sulfide selected from the group consisting of organic disulfide, organic trisulfide and mixtures thereof; and analyzing the reaction products by gas chromatography to determine the amount of sulfur.

1. Field of the Invention
The present invention relates to a method for determining of the amount of sulfur loading in organic polysulfides.
2. Description of the Prior Art
It is known that organic disulfides react with elemental sulfur in the presence of certain catalysts to form organic polysulfides. The average number of sulfur atoms contained in the organic polysulfides is referred to as the "sulfur rank" and is determined by the amount of sulfur actually incorporated into the sulfur-laden disulfide (i.e., the polysulfide).
Recently, catalyzed dimethyldisulfide (DMDS) has become the solvent of choice for removing or preventing the formation of sulfur plugs in sour-gas wells. In fact, in certain wells, solvent must be continuously injected in order to maintain gas production. Accordingly, economics dictate that the sulfur-laden DMDS (i.e., the dimethylpolysulfide, or DMPS) be recovered, and reinjected downhole. Removal of the sulfur from the DMPS is referred to as regeneration. The extent of the sulfur loading must be quantified in order to control and monitor the regeneration process and hence, the overall operation.
Many approaches to the analysis of diand polysulfides have been reported in the literature over the years. The Analytical Chemistry of Sulfur and Its Compounds, J.H. Karchmer, Vol. 29, Part II, Wiley, N.Y., pp. 322-431 (1972), provides an excellent review of these methods.
In Tetrahedron, 18, pp. 205-218 (1962) Moore and Trego reacted triphenylphosphine with dialkyl and diaryl tetrasulfides in benzene to obtain the corresponding disulfides. The reaction was followed by the iodometric titration of the unreacted triphenylphosphine to determine the amount of sulfur loading indirectly by titrating for the disappearance of the phosphine. While this provides the amount of sulfur loading, it does not allow the quantification of the amount of disulfide present in the sample.
The reaction of various phosphorous containing species with di- and polysulfides from the viewpoint of synthesis is known in the art. For example, see J. Am. Chem. Soc., 104, p. 6045 (1982).
High pressure liquid chromatography is useful for determining polysulfide distribution in a sample of well effluent, but is fairly complicated and not suitable for field application.
A method for determining the amount of elemental sulfur present in a material suspected of containing elemental sulfur has been reported by Lesage and Clark in Alberta Sulfur Research Ltd, Chalktalk, Jan. 26, 1988. This method provides for the determination of elemental sulfur by reacting a sample that contains elemental sulfur with triphenylphosphine followed by quantification of the formed triphenylphosphine sulfide by gas chromatography. However, this method does not disclose the determination of sulfur loading in organic polysulfides.
Other examples of the use of gas chromatography to analyze di- or trisulfides are known in the art, e.g., J. Pet. Res., 6 (2), 153-61 (1987); J. Chromatogr., 365, 205-212 (1986); J. Chromatogr. 319 (2) , 187-94 (1985); Am. Chem. Soc., Div. Pet. Chem., 28 (5), 1218-23 (1983); and Clin. Chim. Acta., 130 (1), 103-10 (1983).
However, analysis of polysulfides by gas chromatography has been generally limited to the analysis of polysulfides containing no more than five sulfur atoms due to the instability of higher polysulfide species toward these analytical procedures. That is, consistently accurate results in determining the sulfur rank or extent of sulfur loading in polysulfides cannot be obtained by using the prior art gas chromatographic analysis of polysulfides containing more than five sulfur atoms.
None of these references discloses a method for analysis of higher polysulfides to determine the amount of sulfur loading which may be conveniently used in the field to give consistent results.
The present invention provides an improved method for determining the extent of sulfur loading in an organic polysulfide, including higher polysulfides having more than five sulfur atoms. Moreover, the present invention allows for measurement of the total disulfide content of a given polysulfide sample, as well as of the content of impurities or additives, such as hydrocarbon solvents.

Method for determining sulfur loading in organic polysulfides


Disclosed is a method that involves acquiring an image with text, displaying all or a portion of the image on an electronic device. In response to detecting a swiping action or gesture, displaying a result of translation on a screen of the device. A first screen or display becomes a second one. Original text in a first language or source language may be easily and quickly compared to translated text shown on a second screen through a swiping gesture. Electronic dictionaries and machine translation may be used. These services may be independently stored and operated from different locations including on the device performing the translation, on a server or across a network (LAN, WAN, etc.). Optional manual correction of the translated text is also possible.

1. Field
Embodiments of the invention generally relate to the field of automated translation using electronic dictionaries and various applications in such areas as machine translation.
2. Related Art
There is a lot of electronic devices with display screens capable of displaying text, including devices with a touch screen, for example many mobile devices, such as smartphones, mobile phones, laptops, tablet computers, netbooks, personal digital assistants (PDAs), e-book readers, photo and video cameras.
These devices have enough resources for using electronic dictionaries, which may be installed locally. Machine translation system may be available over the Internet, WiFi, Bluetooth, and through these and other types of networks and protocols.
Many of the aforesaid devices involve advanced displays and associated logic capable of supporting non-keyboard type input methods. For example the devices may support pen-based input, voice-based input or touch-based input.
Also, most of above-identified electronic devices may involve the use of a camera and other components to facilitate receiving, capturing and using photographs and images with text.

Swiping action for displaying a translation of a textual image


An image display apparatus includes display control means for displaying a map image and a real image on a display screen on the same scale concerning the same region based on map data and real image data. The display control means has a function of superposing on either of the map image and the real image as a background, the other image in a predetermined area and combining the images so that only the other image is seen in the superposition area.

The present disclosure relates to the subject matter contained in Japanese Patent Application No. 2002-166512 filed on Jun. 7, 2002, which is incorporated herein by reference in its entirety.
1. Field of the Invention
This invention relates to an image display apparatus and more particularly to an image display apparatus which is adopted for a navigation system and uses real image data corresponding to an image such as a satellite photograph or an aerial photograph of the earth""s surface.
2. Description of the Related Art
A navigation system in a related art can display a map on a screen of a display based on road map data recorded on a DVD-ROM, etc., and further can display the current position on the map and guide the user through the route to the destination based on the position data of the navigation system.
However, since the navigation system in the related art uses the map data to prepare the displayed map image, it is difficult for the user to understand the current position through the map image and grasp the actual circumstances surrounding the current position; this is a problem.
This problem is caused by the fact that the map image is hard to represent the up and down positional relationship of overpass and underpass roads, etc., and that, in fact, a large number of roads, buildings, etc., are not displayed on the map image.
As one of means for solving such a problem, an art of displaying the current position on an aerial photograph image prepared from aerial photograph data is disclosed (JP-A-5-113343). To use the aerial photograph image, a building, etc., as a landmark becomes very easy to understand, thus making it possible for the user to easily understand the current position and also easily grasp the actual circumstances surrounding the current position.
However, the aerial photograph image prepared using aerial photograph data does not always make it possible for the user to more easily understand the current position and more easily grasp the actual circumstances surrounding the current position than the map image prepared using map data; the map image may make it possible for the user to more easily understand the current position than the aerial photograph image.
Therefore, it seems that a navigation system using both an aerial photograph image and a map image rather than a navigation system using only an aerial photograph image or a navigation system using only a map image will be mainstream as a next-generation navigation system. Thus, in the future, it will become important to properly use a real image such as an aerial photograph image and a map image having different features.
It is therefore an object of the invention to provide an image display apparatus which is adopted particularly for a navigation system and can properly use both a real image such as an aerial photograph image and a map image prepared using map data to enhance the user satisfaction.
To the end, according to the invention, according to a first aspect of the invention, an image display apparatus includes a display screen and a display control unit. The display control unit displays a map image and a real image on the display screen on the same scale concerning the same region based on map data and real image data. The display control unit displays one of the map image and the real image as a background. The display control unit combines the map image and the real image in a predetermined region so that only the other is displayed in the predetermined region.
In the first aspect, the one of the map image and the real image (for example, satellite photograph, aerial photograph, etc.,) is displayed as the background and the other is superposed thereon in the predetermined area on the same scale. Furthermore, the images are combined so that only the other is seen in the predetermined region.
For example, when the map image is displayed as the background, in the predetermined area, the composite coefficient of the map image is set to 0 and that of the real image is set to 1 for combining the images, so that only the real image is seen in the predetermined area. Consequently, only the real image is incorporated into a part of the map image, which is displayed as the background on the display screen, so that it is made possible to capture a target, etc., from many other angles.
According to a second aspect of the invention, an image display apparatus includes a display screen and a display control unit which displays a map image and a real image, which have the same scale and show the same area, on the display screen on the basis of map data and real image data. The display control unit displays one of the map image and the real image as a background, combines the map image and the real image in a predetermined region so that the other is seen through the one in at least a part of the predetermined region, and displays the combined image in the predetermined region.
In the second aspect, the one of the map image and the real image. (for example, satellite photograph, aerial photograph, etc.,) is displayed as the background, and the other is superposed in the predetermined area on the same scale. For example, when the map image is displayed as the background, the real image is superposed on a part of the map image, so that it is made possible to capture a target, etc., from many other angles.
Further, in the second aspect, for at least a part of the predetermined region in which the images are superposed on each other, the images are combined so that from under the one of the images, the other becomes transparent.
For example, when the map image is displayed as the background, in the predetermined region, the composite coefficient of the map image is set to xcex1 (0xe2x89xa6xcex1 less than 1) and that of the real image is set to xcex2 (=1xe2x88x92xcex1) for combining the images, and the map image becomes transparent from under (all or a part of) the real image in the predetermined region. Thus, a very large number of pieces of information can be provided for the user.
According to a third aspect of the invention, in the first aspect, the image display apparatus further includes a composite degree setting unit which sets a composite degree of the map image and the real image. The display control unit combines the map image and the real image on the basis of the composite degree.
In the third aspect, the composite degree can be set, so that the user can make adjustment so as to raise the display luminance of the map image (lower the display luminance of the real image) or raise the display luminance of the real image (lower the display luminance of the map image) in the predetermined region in which the images are superposed as desired. Therefore, a display state responsive to the user""s preference can be realized.
According to a fourth aspect of the invention, in any one of the second and third aspects, the display control unit combines the map image and the real image so that luminance value of the combined image increases as approaching to a boundary of the predetermined region.
In the fourth aspect, the images are combined so as to raise the display luminance of the background image as approaching the outside of the superposition area from the superposition region, so that image transition from the superposition region to the outside of the superposition region can be made smooth.
According to a fifth aspect of the invention, a navigation apparatus provide a user with information required reaching a destination to guide the user to the destination. The navigation apparatus includes a display screen and an image display device. The image display device includes a display screen and a display control unit which displays a map image and a real image, which have the same scale and show the same area, on the display screen on the basis of map data and real image data. The display control unit displays one of the map image and the real image as a background. The display control unit combines the map image and the real image in a predetermined region so that the other is seen through the one in at least a part of the predetermined region. The display control unit displays the combined image in the predetermined region.
According to a sixth aspect of the invention, in the fifth aspect, the predetermined region is one of a peripheral region of a current position of a vehicle obtained on the basis of current position information, a peripheral region of a predetermined facility obtained on the basis of predetermined facility position information, and a peripheral region of a predetermined position obtained on the basis of predetermined position information specified by the user.
In the sixth aspect, the predetermined area is any of the region surrounding the current position, the region surrounding the destination, the region surrounding the predetermined facility (for example, a station), or the region surrounding the predetermined position previously specified by the user (for example, home position). Thus, for example, when the map image is displayed as the background, the real image is displayed in the region.
Therefore, an image having different quality from the background image is displayed in the attention region, so that the attention region and any other portion can be discriminated from each other.
According to a seventh aspect of the invention, in the fifth aspect, the predetermined region is one of an upper half of the display screen and a lower half of the display screen.
In the seventh aspect, the predetermined area is the approximately upper half area or the approximately lower half area of the display screen. Therefore, the map image can be displayed in the approximately upper half area and the real image can be displayed in the approximately lower half area or the real image can be displayed in the approximately upper half area and the map image can be displayed in the approximately lower half area.
In the navigation system, often the area surrounding the current position is displayed in the lower portion of the display screen and a location at a large distance from the current position is displayed in the upper portion of the display screen. Thus, in the seventh aspect, an image on a nearby side and an image on a distant side can be discriminated from each other with the current position as the reference.
According to an eighth aspect of the invention, in the fifth aspect, the predetermined region is a peripheral region of a route for the destination obtained on the basis of route information.
In the eighth aspect, the predetermined region is the region surrounding the route. Thus, for example, when the map image is displayed as the background, the real image is displayed in the region surrounding the route.
Therefore, an image having different quality from the background image is displayed in the region surrounding the route, so that the region surrounding the route and any other portion can be discriminated from each other.