Distribution information of examination results of eye fundus is displayed. An imaging part carries out movie imaging of fundus. A tomographic image forming part comprises an optical system that generates and detects interference light by superposing signal light from fundus on reference light and a scanner that scans fundus with signal light, and forms tomographic image of fundus based on detection results of interference light acquired by the scanning. A setting part sets scan-target location of signal light on distribution information. A specifying part specifies image region in fundus image obtained by the movie imaging that corresponds to the scan-target location. A controller controls the scanner based on the specified image region to carry out scanning of signal light. The tomographic image forming part forms tomographic image from the detection results of interference light acquired by the scanning of signal light based on the control.

In recent years, OCT that forms images of the surface morphology and internal morphology of an object by using a light beam from a laser light source or the like has attracted attention. Unlike an X-ray CT apparatus, optical coherence tomography is noninvasive to human bodies, and is therefore expected to be utilized in the medical field and biological field. For example, in the ophthalmology, apparatuses that form images of a fundus and cornea or the like are in a practical stage.
The apparatus disclosed in Patent Document 1 uses a technique of so-called "Fourier Domain OCT." That is to say, the apparatus irradiates a low-coherence light beam to an object, superposes the reflected light and the reference light to generate an interference light, and acquires the spectral intensity distribution of the interference light to execute Fourier transform, thereby imaging the morphology in the depth direction (the z-direction) of the object. Furthermore, the apparatus is provided with a galvano mirror that scans a light beam (signal light) along one direction (x-direction) perpendicular to the z-direction, and is thereby configured to form an image of a desired measurement target region of the object. An image formed by this apparatus is a two-dimensional tomographic image in the depth direction (z-direction) along the scanning direction (x-direction) of the light beam. The technique of this type is also called Spectral Domain.
Patent Document 2 discloses a technique of scanning with a signal light in the horizontal direction (x-direction) and the vertical direction (y-direction) to form multiple two-dimensional tomographic images in the horizontal direction, and acquiring and imaging three-dimensional tomographic information of a measured range based on the tomographic images. As the three-dimensional imaging, for example, a method of arranging and displaying multiple tomographic images in the vertical direction (referred to as stack data or the like), or a method of executing a rendering process on volume data (voxel data) based on stack data to form a three-dimensional image may be considered.
Patent Documents 3 and 4 disclose other types of OCT apparatuses. Patent Document 3 describes an OCT apparatus that images the morphology of an object by sweeping the wavelength of light that is irradiated to an object (wavelength sweeping), detecting interference light obtained by superposing the reflected lights of the light of the respective wavelengths on the reference light to acquire its spectral intensity distribution, and executing Fourier transform. Such an OCT apparatus is called a Swept Source type or the like. The Swept Source type is a kind of the Fourier Domain type.
Patent Document 4 discloses an example of applying OCT to the ophthalmologic field. It should be noted that, before OCT was applied, a retinal camera, a slit lamp microscope, etc. were used as apparatuses for observing an eye (e.g., see Patent Documents 5 and 6). The retinal camera is an apparatus that photographs the fundus by projecting illumination light onto the eye and receiving the reflected light from the fundus. The slit lamp microscope is an apparatus that obtains an image of the cross-section of the cornea by cutting off the light section of the cornea using slit light.
The apparatus with OCT is superior relative to the retinal camera, etc. in that high-definition images can be obtained, further in that tomographic images and three-dimensional images can be obtained, etc.
Thus, the apparatus using OCT can be used for observation of various regions of the eye and is capable of obtaining high-definition images, and therefore, has been applied to the diagnosis of various ophthalmic disorders.


Provided is a sliding member including: a back-metal layer and a sliding layer including a copper alloy. The back-metal layer includes a hypoeutectoid steel including 0.07 to 0.35 mass % of carbon and has a structure including a ferrite phase and pearlite. The back-metal layer has a high ferrite phase portion at a bonding surface between the back-metal layer and the sliding layer. A volume ratio Pc and a volume ratio Ps satisfy Ps/Pc≤0.4, where the volume ratio Pc is a volume ratio of pearlite in the structure at a center portion in a thickness direction of the back-metal layer, and the volume ratio Ps is a volume ratio of pearlite in the high ferrite phase portion.

For a bearing device of an internal combustion engine, an automatic transmission and the like, a cylindrical or semi-cylindrical sliding bearing formed from a sliding member including a sliding layer including a copper alloy and a steel back-metal layer has been used. For example, JP 06-322462A and JP 2002-220631A each describe a sliding member including a sliding layer including a copper-lead bearing alloy or phosphor bronze. According to such a sliding member, a sliding layer including a copper alloy provides seizure resistance and wear resistance as well as a sliding property. On the other hand, a back-metal layer functions as a support of the copper alloy and provides strength to the sliding member.
During operation of the internal combustion engine or the automatic transmission, a sliding member bears a dynamic load from a counter shaft member on a sliding surface of a sliding layer. For example, for holding a sliding bearing, the bearing is fitted into a cylindrical hole of the internal combustion engine, the automatic transmission or the like, and bears a dynamic load from a rotating counter shaft member. In recent years, in order to reduce fuel consumption, weight reduction has been achieved in the internal combustion engine and the automatic transmission, and this has caused the bearing housing to have lower rigidity than before. Accordingly, during operation of the internal combustion engine, in the bearing device of the internal combustion engine and the automatic transmission connected to the internal combustion engine, the bearing housing is more likely to be elastically deformed by a dynamic load from a counter shaft member. Due to the deformation of the bearing housing, the sliding member (sliding bearing) fitted into the bearing holding hole of the bearing housing is elastically deformed in a circumferential direction. Thus, when a varying circumferential force is applied to the sliding bearing of the conventional sliding member, since there is a difference in amount of elastic deformation between the sliding layer including the copper alloy and the steel back-metal layer, shear occurs in some cases at an interface between the sliding layer and the steel back-metal layer. This may cause breakage of the sliding member.
JP 2006-22869A addresses improvement of bonding strength of a bearing alloy layer and a steel back-metal layer. According to JP 2006-22869A, a Cu—Sn—Fe-based alloy is used as a copper alloy. Through heat treatment, a Sn—Fe compound is deposited and grains of the copper alloy are made finer. Thus, the bonding strength of the bearing alloy layer and the steel back-metal layer is increased.


A metrology apparatus for determining a characteristic of interest of a structure on a substrate, the apparatus comprising: a radiation source configured to generate illumination radiation; at least two illumination branches comprising at least one optical fiber and configured to illuminate a structure on a substrate from different angles; and a radiation switch configured to receive the illumination radiation and transfer at least part of the radiation to a selectable one of the at least two illumination branches.

A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern (also often referred to as "design layout" or "design") at a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate (e.g., a wafer).
To project a pattern on a substrate a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features which can be formed on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm and 13.5 nm. A lithographic apparatus, which uses extreme ultraviolet (EUV) radiation, having a wavelength within the range 4-20 nm, for example 6.7 nm or 13.5 nm, may be used to form smaller features on a substrate than a lithographic apparatus which uses, for example, radiation with a wavelength of 193 nm.
Low-k1 lithography may be used to process features with dimensions smaller than the classical resolution limit of a lithographic apparatus. In such process, the resolution formula may be expressed as CD=k1×λ/NA, where λ is the wavelength of radiation employed, NA is the numerical aperture of the projection optics in the lithographic apparatus, CD is the "critical dimension" (generally the smallest feature size printed, but in this case half-pitch) and k1 is an empirical resolution factor. In general, the smaller k1 the more difficult it becomes to reproduce the pattern on the substrate that resembles the shape and dimensions planned by a circuit designer in order to achieve particular electrical functionality and performance. To overcome these difficulties, sophisticated fine-tuning steps may be applied to the lithographic projection apparatus and/or design layout. These include, for example, but not limited to, optimization of NA, customized illumination schemes, use of phase shifting patterning devices, various optimization of the design layout such as optical proximity correction (OPC, sometimes also referred to as "optical and process correction") in the design layout, or other methods generally defined as "resolution enhancement techniques" (RET). Alternatively, tight control loops for controlling a stability of the lithographic apparatus may be used to improve reproduction of the pattern at low k1.
A metrology apparatus can be used to measure parameters of interest of structures on the substrate. For example, a metrology apparatus can be used to measure parameters such as critical dimension, overlay between layers on the substrate and asymmetry of a pattern on the substrate. Rays of measurement radiation are used to illuminate the substrate. The radiation is diffracted by the structure on the substrate. The diffracted radiation is collected by an objective lens and captured by a sensor.
The intensity of illumination may be limited by the power of the radiation source and losses in the optical system of the metrology apparatus. The objective lens may have a high numerical aperture, such as about 0.95. The metrology apparatus may require complicated optics downstream of the objective lens, for example to reduce aberrations in the collected diffracted radiation.

This patent is subject to a terminal disclaimer.


An electrical switching apparatus includes a circuit breaker device having a molded housing with line and load ends, plural terminals disposed from the housing, and first and second handle devices. The terminals electrically and mechanically engage a circuit breaker mounting block. The first and second handle devices engage the housing at or about the respective line and load ends. The handle devices remove the circuit breaker device from the mounting block. Each of the handle devices includes an insulative barrier having a first portion, a second portion and a third portion. The first portion at least partially covers a corresponding one of the housing ends. The second portion is coupled to the housing at or about the corresponding one of the housing ends. The third portion is structured to be manually grasped in order to pull the insulative barrier together with the circuit breaker device away from the mounting block.

1. Field of the Invention
This invention pertains generally to electrical switching apparatus and, more particularly, to an apparatus, such as a circuit breaker, for mounting or plugging-in to a mounting block, such as a plug-in mounting block. The invention also pertains to a mechanism for removing a circuit breaker from a mounting block.
2. Background Information
Electrical switching apparatus, such as circuit interrupters, include, for example, circuit breakers, contactors, motor starters, motor controllers and other load controllers having a trip mechanism. Circuit breakers are generally old and well known in the art. Circuit breakers are used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition or a relatively high level short circuit or fault condition.
It is known to provide an electrical switching apparatus including a molded housing having molded slots between phases, with insulative interphase barriers or terminal shields disposed in those molded slots.
It is known to provide an electrical switching apparatus, such as, for example, a circuit breaker, that is mounted or plugged-in to a mounting or plug-in block, which includes line and load power busses. This permits a maintenance person to remove the circuit breaker by pulling the mounted circuit breaker away from the plug-in block. However, problems might arise during the removal process. For example, known conventional circuit breakers do not include convenient surfaces that can be readily and safely grasped by the maintenance person to pull the circuit breaker for removal from the plug-in block. Also, other known surfaces that might be grasped by the maintenance person often are proximate electrically conductive components, such as, for example, line or load terminals. As a result, the maintenance person may experience difficulty, if not dangers, during the removal process.
Accordingly, there is room for improvement in electrical switching apparatus that is mounted or plugged-in to a mounting or plug-in block.

Handle apparatus and electrical switching apparartus employing the same


A differential amplifier includes a main differential amplifier circuit that receives a pair of input signals and supplies a pair of output signals based on a difference between the input signals; and a bias control differential amplifier circuit that receives the pair of output signals, controls a control terminal of a current-limiting transistor making up the main differential amplifying circuit based on an offset voltage included in the output signals, and reduces the offset voltage.

1. Field of the Invention
The present invention relates to a differential amplifier, a reference voltage generating circuit in which the differential amplifier is used, a differential amplifying method, and a reference voltage generating method in which the differential amplifying method is adopted. Particularly the invention relates to a differential amplifier provided with a circuit that reduces an input offset, a reference voltage generating circuit in which the differential amplifier is used, a differential amplifying method in which the input offset is reduced, and a reference voltage generating method in which the differential amplifying method is adopted.
2. Description of the Related Art
Recently a power supply voltage used in an analog circuit tends to be lowered in order to achieve reduction of power consumption and speed enhancement. For example, Japanese Patent Application Laid-Open (JP-A) Nos. 2006-023920 (corresponding to U.S. Pat. No. 7,215,183), 2007-300623 (corresponding to U.S. Pat. No. 7,336,138), and H05-075431 disclose techniques regarding the differential amplifier applied to the analog circuit. A technique regarding the reference voltage generating circuit in which the differential amplifier is used is disclosed in H. Banba et al, "A CMOS Bandgap Reference Circuit with Sub-1-V Operation" in IEEE Journal of Solid-State Circuits, Vol. 34, No. 5, May 1999, p. 670-673 (hereinafter referred to as Non-Patent Document 1).
The entire disclosures of the aforementioned patent and Non-patent documents are incorporated herein by reference thereto.
However, in the reference voltage generating circuit disclosed in Non-Patent Document 1, the inventor shows that accuracy of output reference voltage is lowered with decreasing power supply voltage and a characteristic of the differential amplifier used has an influence on the lowering of the accuracy. FIG. 9 is a circuit diagram produced by the inventor based on the reference voltage generating circuit disclosed in Non-Patent Document 1, and FIG. 9 is an explanatory view illustrating the problem of the lowering of the accuracy of the reference voltage. In cases where the reference voltage generating circuit (reference voltage generating circuit in which a bandgap circuit is used) of FIG. 9 is operated at a low voltage, dependence of reference voltage output Vref on a power supply voltage is increased as the power supply voltage is lowered. When the dependence on the power supply voltage is increased, the reference voltage is largely changed by the slight change in power supply voltage, and therefore the reference voltage becomes unstable. This means the accuracy of the reference voltage comes down. A factor the dependence of the reference voltage output Vref on the power supply voltage is increased includes an insufficient output resistance of constant current source MOS (Metal Oxide Semiconductor) in an output stage and an input offset voltage generated by a finite gain of a differential amplifier used in the circuit, and the latter is the main factor. The input offset voltage of the differential amplifier, which becomes the main factor in lowering the accuracy of reference voltage supplied from the reference voltage generating circuit, will be described with reference to FIG. 18. The differential amplifier of FIG. 18 includes a differential pair of NMOS (N-type MOS) transistors and current mirror type load circuit of PMOS (P-type MOS) transistors, and an output is brought into contact with a negative input terminal to form a voltage follower circuit. When the differential amplifier has a sufficiently high amplification factor, potentials at a positive input terminal and an output terminal are equal to each other in the differential amplifier. However, because the differential amplifier has the finite amplification factor, a slight potential difference remains between the positive input voltage and the output voltage. This is the input offset voltage. The input offset will be described in detail. In the differential amplifier of FIG. 18, it is assumed that gm is mutual conductance of the differential pair of NMOS transistors and rds is a drain resistance of the current mirror type load circuit of the PMOS transistors that become a load. It is also assumed that VOUTb is a potential at gates commonly connected in the current mirror type load circuit of the PMOS transistors and VOUT is a potential at the outputs of the PMOS transistors. At this point, (VDD-VOUTb) is a drain-source voltage of the diode-connected PMOS transistor while (VDD-VOUT) is a drain-source voltage of the PMOS transistor connected to the output side. Accordingly, a drain voltage difference ΔVDSp between the PMOS transistors is expressed by an equation (1):ΔVDSp=(VDD−VOUTb)−(VDD−VOUT)=VOUT−VOUTb  (1)
A current error ΔIp caused by the drain voltage difference ΔVDSp in the current mirror type load circuit is expressed by an equation (2):ΔIp=ΔVDSp/rds=(VOUT−VOUTb)/rsd  (2)
On the other hand, an input offset voltage ΔVIN is expressed by an equation (3):ΔVIN=VIN−VOUT  (3)
A current difference ΔIn caused by the input offset voltage ΔVIN in the differential pair of NMOS transistors is expressed by an equation (4):ΔIn=gm·ΔVIN=gm·(VIN−VOUT)  (4)
Because ΔIp and ΔIn are equal to each other, the input offset voltage ΔVIN can be expressed as follows from the equations (2) and (4):ΔVIN=(VOUT−VOUTb)/(gm·rsd)  (5)
As can be seen from the equation (5), there are two methods of reducing the input offset voltage ΔVIN.
(1) A voltage amplification factor Av=gm·rds of the differential amplifier circuit is increased.
(2) The potential VOUTb at the gates commonly connected in the current mirror type load circuit of the PMOS transistors is equalized to the potential VOUT at the outputs of the PMOS transistors (VOUT=VOUTb).
As to the first method, the drain resistance rds is increased by forming the current mirror type load circuit into a cascode type load circuit, thereby increasing the voltage amplification factor Av=gm·rds of the differential amplifier circuit. However, disadvantageously an operating range of the power supply voltage is degraded by a voltage necessary for the cascode type load circuit. Therefore, particularly the first method is not suitable to a low-power circuit. As to the second method, the potential VOUTb at the gates commonly connected in the current mirror type load circuit of the PMOS transistors is substantially determined by threshold voltages of the PMOS transistors. On the other hand, the potential VOUT at the output of the current mirror type load circuit of the PMOS transistors is determined by a circuit configuration, and generally the potential VOUTb and the potential VOUT are hardly equalized to each other in any state. Although JP-A Nos. 2006-023920, 2007-300623, and H05-075431 disclose the reference voltage generating circuit operated at a low voltage, there is no suggestion about the influence of the input offset voltage on the accuracy of output voltage. Accordingly, even if the disclosed techniques are referred to, unfortunately there is no suggestion about the differential amplifier that can be used at a low voltage without the influence of the input offset voltage and the reference voltage generating circuit.

Differential amplifier, reference voltage generating circuit, differential amplifying method, and reference voltage generating method


An air conditioner cover adapted to cover an entire outdoor air conditioner unit. The cover is made from a perforated neoprene material and is comprised of a horizontal top panel joined to an attachment skirt extending perpendicularly downward therefrom and an extended skirt protruding downwardly from the attachment skirt covering the remainder of the air conditioner unit.

This invention relates to air conditioners, and in particular to a cover for an outdoor air conditioner unit.
Split system air conditioners are widely used in which an outdoor unit houses the compressor, condenser, fan, and control components. The outdoor unit is installed near the exterior of the building in which the evaporator is located.
Split system air conditioners are usually made with an open-grill construction to eliminate moisture build-up within the unit. However, the open-grill construction exposes the unit's motor and other operative parts to debris such as leaves. Protective covers for outdoor units are known in which a shroud of flexible, weather resistant material envelops the outdoor unit to protect against the weather, moisture, dirt, leaf particles, and other debris when the unit is not in use. However, these protective covers are moisture impervious and permit humidity to develop under the cover within the unit thereby corroding the structure and operative parts of the unit.


A generic RAID engine system accepts an access request, accepts a metadata input comprising a layout description and, optionally, a plurality of resource optimization objectives, accepts a dynamic input comprising a dynamic state of an I/O stack comprising the generic RAID engine and a fault configuration of a plurality of storage devices in the I/O stack, and accepts RAID code input comprising information about the RAID code used by the I/O stack. The metadata input, the dynamic input, and the RAID code input are utilized to transform the access request into individual device reads and individual device writes such that RAID code relationships for the storage devices are maintained at all times. An optional optimizer module selects strategies that meet the resource optimization objectives.

Conventional applications requiring reliable data storage typically use commonly available RAID (redundant array of independent disks) levels to protect against data loss due to media or disk failures. Although conventional RAID technology has proven to be useful, it would be desirable to present additional improvements. With a marked rise in the quantity of stored data and no commensurate improvement in disk reliability, a variety of RAID codes are becoming essential to containing data management costs. However, rolling out new RAID codes is challenging as well as cost prohibitive since the new RAID codes require significant development, testing, and tuning efforts.
Until recently, protecting customer data from loss due to media failure and/or device failures meant storing the using one of a basic set of RAID codes representing various levels of data protection and storage performance. To handle higher performance and reliability needs of customers, storage vendors deployed additional codes (e.g., RAID 51) as variations on that basic set. These additional codes were primarily offered as a result of juggling the inherent risk-reward trade-off from a software engineering standpoint as opposed to improving storage efficiency or performance. These additional codes can be composed by reusing (e.g., hierarchically) the basic RAID set, thus minimizing the amount of additional source code introduced. Consequently, product-marketing needs were satisfied with a low testing expense.
Only a few RAID codes were supported in traditional RAID implementations (firmware) for a variety of reasons: firmware complexity, software maintainability, and field upgrade difficulty. Firmware complexity, as measured by the number of paths that need to be tested, grows with every supported RAID code. Increased complexity increases development and test costs. The firmware becomes a collection of special cases making it hard to perform path length optimizations. In addition, performance tuning becomes difficult, if not prohibitively expensive.
From a software maintainability standpoint, a collection of "if . . . then . . . else . . . " code blocks makes firmware readability harder, making the firmware more prone to bugs. Each rollout of a RAID code requires field upgrades. Upgrading firmware and drivers is not a task that a storage administrator relishes, given the propensity of upgrades to trigger other problems.
Since deploying firmware changes is painful, there is a general mindset to avoid it all costs. However, recent trends in storage technology and customer focus are forcing a re-evaluation of this status quo because of a need for supporting a variety of RAID codes in a system, growth in reference data, a growing popularity of modular systems, and a growing use of low cost serial disks to build high performance systems.
No single RAID code satisfies all aspects of data storage. In a world where the volume of customer data is rising due to various reasons from business transformation to regulatory requirements, it is becoming increasing important to store data at levels of reliability, performance and efficiency that are proportional to the "business" value of the data. Information life-cycle management (ILM) is becoming crucial to cost containment. Supporting a variety of RAID codes thus becomes integral to effective information life-cycle management.
The additive nature of reference data in organizations implies that the same storage manages a wide variety of scales of data sets from gigabytes to petabytes at the same reliability level. Using a single RAID code in this application is challenging. These datasets typically span many disks, indicating a relatively high probability of simultaneous failures. Furthermore, while disk capacities are increasing, the hard error rate (HER) due to media deterioration, channel errors, etc., has remains relatively constant. Combined, these trends raise the frequency of data loss events as data sets grow unless RAID codes with a higher fault tolerance are used.
The use of modular (or brick) systems to build storage systems that scale capacity, reliability and performance simultaneously is a trend that is gaining popularity. Many of these systems embrace deferred maintenance to reduce the cost of managing such systems. In a "fail in place" service strategy, software isolates failed components and rebuilds stored data on surviving bricks. As long as there is sufficient spare capacity, replacement of failed components can be deferred to bi-annual or multi-year cycles.
A further trend is the growing use of low cost serial ATA (SATA) disks to build high performance systems. SATA disks have hard error rates that are 10 times higher than comparable SCSI disks while costing about 35-55% less. Consequently, providing various data reliability levels using cheaper but less reliable disks requires a greater variety of RAID codes.
One conventional approach, RAIDframe, focuses on providing firmware environments that permit rapid prototyping and evaluation of redundant disk array architectures. Although this approach has proven to be useful, it would be desirable to present additional improvements. This approach modularizes the basic functions that differentiate RAID architectures: mapping, encoding, and caching. This modularization allows each aspect to be modified independently, creating new designs. In RAIDframe, array operations are modeled as directed acyclic graphs (DAGs) that specify the architectural dependencies (and execution) between primitives. RAIDframe provides no simplification or automation of error handling. Furthermore, RAIDframe has no ability to automatically tune performance.
Other conventional approaches utilize a RAID system-on-a-chip (SOC) product. Although these approaches have proven to be useful, it would be desirable to present additional improvements. For example, one such approach contains an embedded processor, DMA/XOR engines, and host and disk interface logic (FC and SATA). Since the processor is programmable, it is conceivable that this approach may support a variety of RAID codes. However, all error paths are specified as callbacks written by the developer. Further, tuning of this performance approach is only minimally automatic, if at all.
What is therefore needed is a solution to provide a variety of RAID codes without compromising the quality, performance, and maintainability of the firmware. Such a method allows for adding new RAID codes without bloating the firmware. Many RAID codes have been proposed such as, for example, EVENODD, generalized EVENODD, X-code, RDP, and WEAVER. A common trend in these RAID codes is to focus on XOR-based RAID codes since they can be efficiently implemented in hardware or software. Non-XOR codes such as LDPC and Reed-Solomon have been developed, but these have not become popular since they offer no special advantage over XOR based codes.
A solution is required to automatically handle any RAID code related error. An example of such an error path is, on a read, encountering a read error due to a failed sector or disk. Since error handling is a large fraction of a firmware, the solution should unify fault-free and fault-ridden cases into common code paths.
The solution is further required to simplify nested error paths inherent in firmware. An example of a nested error path is when, in the process of reconstructing a lost block due to a previous failure, a new sector or disk failure is discovered. If the RAID code encounters such nested error paths, the solution is required to automatically determine how to reconstruct the lost block.
Furthermore, the solution is required to automatically tune performance for every I/O operation performed by leveraging: dynamic state such as currently cached pages.
What is therefore needed is a system, a service, a computer program product, and an associated method for providing a generic RAID engine and optimizer. Such a system should work for any XOR-based erasure (RAID) code and under any combination of sector or disk failures. The need for such a solution has heretofore remained unsatisfied.

System, method, and service for providing a generic RAID engine and optimizer

International Business Machines Corporation


An unmanned aerial vehicle (UAV) includes a fuselage that supports breakaway components that are attached using magnets. One component is a battery pack which powers the vehicle. Another component is a rotor set including two identical pod pairs that each support a motor and a propeller. Each motor is attached to a hub assembly that includes a plurality of spokes captured in a motor hub and sandwiched by a rigid motor printed circuit board on top and a rigid hub plate. The hub assembly construction is rigid in plane and functions to keep the motor firmly stable during operation. The hub assembly is compliant and resilient when impacted parallel to the plane. Other features of the pod pairs encage the otherwise dangerous spinning propeller. This allows the vehicle to operate with a higher level of safety than conventional UAVs.

Small UAVs are increasingly used for aerial reconnaissance, typically recording video and still images for later viewing, or viewing in real-time. Depending on the size and desired lift-capacity, a typical UAV is powered by either a single gas-powered engine or several electric powered motors with the required thrust for lift being generated by at least one, but usually three or more spinning propellers. Each propeller includes one or more radially disposed blades extending from a central hub. The hub of each propeller is mechanically connected, either directly or indirectly through a transmission, to the drive shaft of the engine or each motor used. At first glance, a UAV resembles a radio controlled model helicopter, except that a helicopter's conventional tail rotor is not required with a UAV since the multi-propeller design effectively cancels out any propeller-generated rotational thrust that must otherwise be controlled using a tail-rotor in single-propeller designs.
As with model helicopters, the unprotected spinning blades pose a tremendous risk with the potential of inflicting damage to the craft itself or nearby property, but more importantly to the operator of the UAV or other people or animals.
Many attempts have been made to protect the blades by enclosing them in rigid frame structures or using so-called prop guards, which either partially surround or fully encircle the propellers. These frame structures or guards are generally made from EPS (expanded polystyrene), injected molded plastics, or composites and although are usually effective at preventing accidental side-contact with a spinning propeller, they usually do not survive moderate impact, should the UAV impact an object during flight. These prior art prop-protecting structures typically flex and deform during impact and cause damage to the craft and the propellers.
While each approach to protect the propeller from damage or contact has specific benefits, they all also include one or more weaknesses, such as being too heavy, too fragile, too large, creating excessive wind drag, or creating unwanted turbulence around the spinning propeller, which reduces performance and efficiency. Additionally, when these protections only protect the tips of the spinning propellers from the side, it remains possible to access the propellers from either the top or bottom. This accessibility creates a tremendous hazard to a person's fingers and also makes the propellers vulnerable to damage from sticks, rocks, or any other foreign objects.
Another problem with conventional UAVs is that they rarely survive impact and often become "grounded" until a broken part can be repaired or replaced. The fragility of conventional UAVs is both frustrating and counter-productive to carrying out their intended task.


A supervisory channel is provided on an optical path (31) between nodes of an optical communication network. The nodes are arranged to use a set of wavelengths allocated for carrying traffic channels. An optical signal (16) which carries a supervisory channel is generated at a supervisory channel transmitter (15) and added (12) to the optical path (31) downstream of an optical amplifier (11). The optical signal (16) has a wavelength which is one of the set of wavelengths allocated for carrying traffic. The method is performed at a time when the wavelength is not being used to carry traffic. An impairment parameter of the received optical signal is measured at a supervisory channel receiver (15). The receiver is a coherent receiver and the impairment parameter is chromatic dispersion or polarization mode dispersion.

Today, dynamic optical networks use all optical switching technology such as Wavelength Selective Switch (WSS) embedded in (Remotely) Reconfigurable Add Drop Multiplexer (ROADM). The Generalised Multiprotocol Label Switched (GMPLS) application to photonic networks is called Wavelength Switched Optical Network (WSON).
The International Telecommunication Union ITU-T G.692 Recommendation defines an Optical Supervisory Channel (OSC) as "A channel that is accessed at each optical line amplifier site that is used for maintenance purposes including (but not limited to) remote site alarm reporting, communication necessary for fault location, and orderwire. The Optical Supervisory Channel is not used to carry payload traffic".
In practical implementations the OSC is an additional wavelength λOSC, usually outside the optical amplifier (Erbium-Doped Fibre Amplifier (EDFA)) amplification band at 1510 nm, 1620 nm, 1310 nm or another proprietary wavelength. The OSC carries information about the DWDM optical signal as well as remote conditions at the optical terminal or amplifier site. It is also normally used for remote software upgrades and network management information. The OSC signal structure is vendor specific, even if the ITU standard suggests using an OC-3 signal structure. The OSC is always terminated at intermediate nodes, where it receives local information before retransmission. This contrasts with wavelengths which carry client signals (i.e. traffic), which are only terminated at endpoints of a lightpath.
Increasing bit rates from 2.5 Gbit/s to 100 Gbit/s and higher, combined with the increasing number of wavelengths from 16 to 160 and the narrowing of the channel spacing, impacts the routing of a lightpath due to physical constraints, which are often referred to as impairments. The effect of such impairments should be considered during the process of computing a lightpath between a source node and a destination node to be sure that the optical signal carried over the lightpath will have sufficient quality to detect the carried traffic at the receiver interface. This quality is usually quantified using a Quality of Transmission (QoT) parameter, like the Q factor, which is strictly related to the Bit Error Rate (BER).
In an opaque optical network, a traffic-carrying optical signal is converted between the optical domain and the electrical domain at each intermediate node. In a transparent optical network a lightpath remains in the optical domain between the source node and destination node, without conversion between the optical domain and electrical domain at intermediate nodes. So, it is only possible to monitor the signal quality at the destination endpoint of a lightpath, such as by measuring the BER at the receiver, or at an intermediate regeneration point, if one is provided along the lightpath. BER provides a measurement of the QoT as resulting from the concurrent action of multiple physical effects without distinguishing among each single cause of detrimental effects.
This scarce and limited availability of quality related information makes it difficult to perform a path computation which is fully aware of the real impact of the impairments that the signal will experience on the path from the source node to the destination node.


A method and computer program are provided for analyzing a set of layers within an integrated circuit design to determine a set of critical points for each layer within the set of layers. The critical points are based at least in part on manufacturer specific process parameters. The method includes assigning a critical point value to each of the critical points within each set of critical points, analyzing a path through the integrated circuit design across multiple integrated circuit design layers, and determining a sum of critical point values of each critical point along the path.

Integrated circuits may be formed using various photolithographic techniques. Such techniques typically involve exposing a photoresist layer to a light source through a patterned photo-mask. In general, the final pattern formed onto the photoresist layer does not precisely match the designed pattern for which the final pattern was formed. This is caused by various photolithographic process parameters such as the resolution of the light source. It is important to ensure that the final printed pattern is not so far from the designed pattern that functionality of the circuit is adversely affected.
In many cases, the entity that designs a circuit is different from the entity that manufactures the circuit. Because the manufacturing processes, such as the photolithographic processes include parameters that are specific to a particular integrated circuit manufacturer, the manufacturer must analyze each layer of the design separately to ensure that a particular layer does not include circuit features that may cause an issue with the manufacturers photolithographic processes. Various tools exist to perform this check. An example of such a tool is Litho Process Check (LPC) by Cadence Design Systems, Inc. These tools, however, analyze each layer separately and do not factor in effects from other layers
Additionally, the circuit designing entity often uses various tools to find critical paths through the circuit. One example of such a tool is On-Chip Critical Path. Such tools allow the circuit designer to determine things like critical paths through the circuit and assist the designer with time delay, cost reduction, trouble shooting, and other issues. Such tools will analyze multiple layers together. However, such tools do not factor in any manufacturer specific photolithographic process parameters. Consequently, it is desired to have a tool that will allow circuit designers or manufacturers to consider both critical path issues from multiple layers as well as manufacturer specific photolithographic process parameters.

Chip level critical point analysis with manufacturer specific data

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.


The present invention discloses a high throughput screening method and system, which can be used to screen a plurality of fluid samples to ascertain their corresponding information. For example, a polymer solution sample is screened to ascertain information about its micro structure character such as including its crystallinity property. The high throughput screen system comprises a plurality of sampling passages and one or more screening devices for screening multiple samples simultaneously or almost simultaneously to get their corresponding information so as to meet research requirement of the relevant field.

Polymer microstructure characterization is the basis for developing new species and brands of polymers. At present, for a polymer such as a synthetic resin, its molecular weight, isotacticity and crystallinity are statistical average values, which can not reflect its real structure and properties information. Therefore, a correct classification method is important for microstructure research.
In polymer structure classification methods, besides the structure classification method based on relative molecular mass, the structure classification method based on degree of crystallinity has been used widely. The degree of crystallinity of the polymer is related to its chemical constituents, sequence, isotacticity distribution and branched degree, etc. and affects its mechanical property, thermodynamics property and machining property greatly. So, it is important to analyze the degree of crystallinity the polymer for the research on the polymer property and its grade.
The crystal classification method is to separate the polymer based on relationship between the crystallization of the polymer in its solution and the temperature. One is TREF (Temperature Rising Elution Fractionation), which is widely used in the polyolefin structure characterization. Recently, a new crystal classification method named as crystallization analysis fractionation (CRYSTAF) is developed, which is operated by decreasing temperature. The CRYSTAF is a one step separation method, which may need less time than a two-step separation of the TREF. So it is used widely.
Although the analyzing speed of the CRYSTAF is rapid than that of the TREF, the overall analyzing process of the CRYSTAF still needs much time such as two or more hours. So, it may slow down the development speed. In order to increase the development speed, a lot of screen devices are developed to meet the requirement for high throughput samples screen, such as including CRYSTAF 200+ of Polymer Char, which employs a selectivity valve to input a plurality of samples to the screen device in turn, and then screens the samples orderly. However, the screen device can only screen one sample one time. So, it can not meet the requirement for screening a plurality of samples simultaneously in a relatively short time. A bottleneck of the analyze speed is still existed.
Therefore, it is desired to develop a new high throughput screen method, which can screen a plurality of samples in a relatively short time to overcome drawbacks of the prior arts, The new screen method can screen the plurality of samples simultaneously or almost simultaneously. So, each sample can be screened continuously or almost continuously.
In order to match the high throughput screen method, it is also desired to develop a high throughput samples preparation method to provide the samples for screening. Thus the preparation and the screen of the samples can be accomplish continuously to improve efficiency of the polymer development and meet the requirement of the field on polymer development.

High throughput screen method and system


Peptides are produced as fusions with a suitable carrier protein. The carrier protein disclosed herein are adapted from the N-terminal domain of staphylococcus nuclease. This novel carrier protein acts to promote the over-expression of the peptide-protein fusion in the form of inclusion bodies, which minimizes in-cell proteolysis of desired peptides. The fusion protein is readily purified by conventional procedures or His-tag affinity chromatography when His-tag is inserted into the fusion protein. The target peptide is released from the purified fusion protein by a simple cleavage step and separated from the librated carrier protein by use of a reverse-phase HPLC process or by repeating the same affinity purification method. A particular advantage of the disclosed method, in addition to the obvious advantage of high yields, is its use for producing isotopically labeled peptides for NMR characterization of bioactive peptides and their interactions with target proteins.

(a) Field of the Invention
The present invention relates generally to methods of producing recombinant peptides by using of novel carrier proteins derived from the wild-type staphylococcus nuclease and its mutants.
(b) Description of Prior Art
Peptides constitute a group of biomolecules for which there is an increasing demand in many fields of biological, medical and pharmaceutical research. The increasing popularity of genome-scale protein studies or proteomics is further to increase the use of peptides for functional characterization and target validation. In addition to the use of peptides as drugs (Latham, P. W., Nature Biotech. 17, 755-757, 1999), peptides are also tools for investigating protein-protein interactions and as lead molecules for drug design. Indeed, the bound conformations of peptides in complex with target proteins are commonly used as templates for the discovery of small-molecule drugs (Mazitschek, R. et al., Mini. Rev. Med. Chem., 2; 491-506, 2002). There is also increasing evidence for the existence of peptide-like, or naturally unfolded, proteins which are encoded by the genomes and endowed with critical functional activities (Wright, P. et al., J. Mol. Biol., 293; 321-331, 1999; Uversky, V., Prot. Sci., 11; 739-756, 2002; Dunker, A. et al., Biochemistry, 41; 6573-6582, 2002).
Currently, chemical methods are used for the preparation of a variety of pharmaceutical peptides such as calcitonin, PTH, bivalirudin or other hirudin analogs and insulin. These purely chemical methods require the condensation of the corresponding amino acids or peptide fragments and very often suffer from cost disadvantages due to the use of elaborate purification methods and sometimes unnatural amino acids required. Given the increasing demand for peptides in pharmaceutical and biotechnology research, it is somewhat surprising that the main source of peptides still comes from synthetic techniques. Although solid-phase synthesis can produce good yields of peptides, the cost of synthetic peptides becomes unviable and/or prohibitively high when the desired peptide is greater than 30 residues. Moreover, uniform isotopic enrichment with 15N/13C or 2H for NMR studies is practically impossible for larger peptide fragments by solid-phase peptide synthesis.
For many years, it has been a common practice to use fusion proteins for the expression of small peptides. The commercially available carrier proteins are GST from Pharmacia, CBD from NEB, and some others from Novagen. Most fusion carriers have been selected to increase the solubility of the fusion constructs and the fusion carriers have been so large that the final yields of the expressed peptides are very low. The large sizes of the fusion carriers also complicate the purification steps of recombinant peptides. These findings indicate that production of recombinant peptides has been problematic for many (often unknown) reasons. In particular, the large size of the fusion carrier often limits the final yield of the target peptide. Quite often, secondary cleavage sites release undesirable peptides from the fusion carrier, which complicate the purification procedure. Sometimes, the fusion protein needs to be solubilized in a suitable buffer to facilitate peptide release by use of a specific protease. This is especially the case when there is at least one cleavage site (e.g. by CNBr) within the targeted peptide. Moreover, the production of peptides for preclinical and clinical evaluations often requires multi-gram quantities (Latham, P. W., Nature Biotech. 17, 755-757, 1999). To achieve the latter goal, high-yield expression of the fusion protein and simplified downstream processing steps need to be developed by the engineering of new carrier proteins.
Recombinant production of peptides has many advantages over chemical (solid-phase) synthesis including potentially higher yield, lower cost, easier scale-up and less environmental contamination. Although any polypeptide chain can be theoretically expressed in any microbial system, expression of peptides can sometimes be problematic in microbial hosts, such as Escherichia coli. The stability of the peptide expressed often results in a diminishingly low yield. In fact peptides expressed in a host cell can be degraded quickly by endogenous proteases and assimilated by the host cell. To overcome this problem, peptides can be expressed as fusion proteins with a suitable carrier protein. The fusion protein may in addition direct the peptides to specific subcellular compartments or inclusion bodies with the goal of achieving high yield of expression and avoiding protease degradation. The most significant carrier proteins used for the expression of peptides are listed as follows.
BPI
Better reported methods to produce human a atrial natriuretic peptide (U.S. Pat. No. 5,851,802 and WO00/55322). The inventor designed a series of recombinant expression vectors that encode peptide sequences derived from bactericidal/permeability-increase protein (BPI) as carrier proteins.
Carbonic Anhydrase
Partridge et al described methods to produce recombinant peptides by use of carbonic anhydrase as the carrier protein (WO96/16297). Three peptides including GRF (1-41), GLP1(7-34) and PTH(1-34) had been successfully prepared in this system. Wagner et al also developed a process for the recombinant preparation of a calcitonin fragment by using the same carrier protein and the use of the fragment in the preparation of full-length calcitonin and related analogs (U.S. Pat. No. 5,962,270, and WO97/29127).
α-lactalbumin
Cottingham et al invented a process to produce peptides as fusion proteins of α-lactalbumin in the milk of transgenic mammals (WO95/27782). The fusion partner acts to promote the secretion of the peptides and allows a single-step purification based on the specific affinity of α-lactalbumin to its antibodies. The peptide is released from the purified fusion protein by a simple cleavage step and purified from the liberated α-lactalbumin by repeating the same affinity purification method. This route provided a particular advantage of producing peptides that require specific post-translational modifications.
β-galactosidase
Shen used β-galactosidase as a carrier protein to express pro-insulin in inclusion bodies (Shen S., PNAS, 281; 4627-4631, 1984). The isolated inclusion bodies were solubilized with formic acid and cleaved with cyanogen bromide. Kempe et al used β-galactosidase as a carrier protein to express multiple repeats of the neuropeptide substance P in inclusion bodies of E. coli (Kempe T. et al., Gene, 39; 239-245, 1985). The peptide was released from the fusion protein by CNBr cleavage in a formic acid solution. Lennick et al also used this protein in a fusion system to express human α-atrial natriuretic peptide (Lennick M. et al., Gene, 61; 103-112, 1987). The target peptide was inserted as multiple repeats and the purified inclusion bodies were solubilized with urea followed by endoprotease cleavage. Schellenberger et al reported a process to express insoluble inclusion bodies of a fusion protein encoding a substance P peptide with β-galactosidase (Schellenberger et al., Int. J. Peptide protein Res., 41; 326-332, 1993). The isolated fusion protein was treated with chymotrypsin to separate the peptide from the carrier protein.
Chloramphenicol Acetyltransferase
Dykes et al reported a method to express human α atrial natriuretic peptide as a soluble intracellular fusion protein with chloramphenicol acetyltransferase in E. coli (Dykes C. et al., Eur, J. Biochem, 174; 411-416, 1988). The fusion protein was proteolytically cleaved or chemically cleaved with 2-(2-nitrophylphenylsulphenyl)-E-methyl-3′-bromoindolenine to release the peptide.
Glutathione-S-Transferase (GST)
Ray et al used glutathione-S-transferase (GST) to carry salmon calcitonin as a soluble intracellular fusion protein. The peptide was purified after the fusion protein was cleaved with cyanogen bromide. Hancock et al fused human neutrophil peptide 1 (HNP-1) or a hybrid cecropin/mellitin (CEME) peptide with GST and expressed the fusion proteins as inclusion bodies (WO94/04688, and Ray et al., Bio/Technology, 11; 64, 1993). Williamson et al used the GST expression system for the rapid and economic expression of recombinant neurotensin peptide (Williamson P. et al., Protein Exp. and Purif., 19; 271-275, 2000).
L-ribulokinase
Callaway et al reported a process to use L-ribulokinase as a carrier protein to express a cecropin peptide (U.S. Pat. No. 5,206,154, and Callaway et al., Antimicrob. Agents & Chemo, 37; 1614-1619, 1993). The fusion protein was expressed as inclusion bodies. The fusion protein was first isolated and then solubilized in formic acid prior to CNBr cleavage.
gp-55 Protein
Gramm et al used a bacteriophage T4-encoded gp-55 protein to fuse a human parathyroid hormone peptide (PTH) (Gramm H. et al., Bio/technology, 12;1017-1023, 1994). The fusion protein was expressed as inclusion bodies. The inclusion bodies were reacted with milder acid to hydrolyze an engineered Asp-Pro cleavage site.
Ketosteroid Isomerase
Kuliopulos et al reported the expression in insoluble E. coli inclusion bodies of a fusion protein encoding multiple repeats of a yeast α-mating peptide and a bacterial ketosteroid isomerase protein (Kuliopulos A. et al., J. Am. Chem. Soc., 116; 4599-4607, 1994). The isolated fusion protein was solubilized with guanidine hydrochloride prior to cyanogen bromide cleavage. Majerle et al (Majerle A. et al., J. Biomol. NMR, 18; 145-151, 2000) have demonstrated that isotope-labeled peptides could be prepared based on the peptide expression system first described by Kuliopulos et al. It was shown that recombinant peptide production had potentially many advantages over the solid-phase method of peptide synthesis, especially for isotope-labeled peptides of ˜10 residues in size.
Ubiquitin
Pilon et al described soluble intracellular expression in E. coli of a fusion protein encoding peptides fused to ubiquitin. The fusion protein was cleaved with a ubiquitin specific protease (UCH-L3) (Pilon A. et al., Biotechnol. Prog., 13; 374-379, 1997). Kohno et al also used ubiquitin to fuse mastoparan-X, a tetrdecapeptide known to activate GTP-binding regulatory proteins (Kohno T. et al., J. Biomol. NMR, 12; 109-121, 1998).
Bovine Prochymosin
Hauht et al reported the expression of a fusion protein encoding an antimicorbial peptide designated P2 and bovine prochymosin as insoluble inclusion bodies in E. coli (Hauht et al., Biotechnol. Bioengineer., 57; 55-61, 1998). The purified inclusion bodies were solubilized in formic acid and cleaved with cyanogen bromide.
GB1 Domain
Darrrinm et al used the GB1 domain as carrier protein to express the inhibitory region of Ctnl, clp (Darrrinm et al., Biochemistry, 41; 7267-7274, 2003). The fusion strategy takes advantage of the small size, stable fold and high bacterial expression capability of the GB1 domain to allow direct NMR spectroscopic analysis (Huth J et al, Protein Science, 6; 2359-2364, 1997). Pei et al used the GB1 domain as a solubility-enhancement tag (SET) for NMR studies of poorly behaving proteins (Pei et al., J. Biomolecular NMR, 2001).
RNA-Binding Domain
Sharon et al reported an expression system to produce the 23-residue V3 peptide, the third variable loop of the envelop glycoprotein (gp120) of the HIV virus, linked to a derivative of the RNA-binding domain of the human hnRNP C protein (Sharon M. et al., Protein Exp. and Purif., 24; 374-383, 2002).
SH2 Domain
Fairlie et al reported the use of the N-terminal SH2 domain of the intracellular phosphatase, SHP2, as a carrier protein to express six peptides of ˜14 residues in length. This small protein domain confers an advantage for the production of disulfide-containing peptides (Fairlie W. et al., Protein Exp. and Purif., 26; 171-178, 2002).
A number of other publications have reported alternative peptide expression systems and described their utility for the production of one or two specific peptides (Baker, R., Curr. Opin. Biotechnol., 7; 541-546, 1996; Campbell, A. et al., Biochemistry, 36; 12791-12801, 1997; Jones, D. et al., Biochemistry, 39, 1870-188, 2000; Lindhout, D. et al., Biochemistry, 41; 7267-7274, 2002; Sprules T. et al., J. Biol. Chem., 278; 1053-1058, 2003). In general, the target peptides are fused to a highly expressed carrier protein in order to overcome the problem of low yields of peptide production. In some cases a carrier protein with low solubility has been exploited to direct the peptide to the inclusion bodies, thereby minimizing proteolysis and simplifying purification (Kuliopulos A. et al., J. Am. Chem. Soc., 116; 4599-4607; 1994; Majerle A. et al., J. Biomol. NMR, 18; 145-151, 2000; and Jones, D. et al., Biochemistry, 39; 1870-188, 2000).
However, there is still the question of expression yields and whether the available method is suitable for the production of peptides of larger sizes. Currently available methods for peptide expression also have many technical problems especially for the production of pharmaceutical peptides of small to medium sizes (e.g. >30 residues), which are often required for reducing side effects. Practically, it is very difficult to produce peptides using a normal recombinant system such as the GST fusion expression vector. The peptides are either not expressed or degraded by proteases for unknown reasons.
It would be highly desirable to be provided with a new fusion protein overcoming the drawback of the prior art, for the production of recombinant peptides.

Staphylococcal nuclease fusion proteins for the production of recombinant peptides


An emergency routing number is assigned to each switch in a wireless network. When a switch of the wireless network routes an emergency call to a Public Service Answering Point (PSAP), the switch sends the emergency routing number as the calling party number and provides the PSAP with the identifier of the mobile station. If the emergency call drops, the PSAP performs a call back using the emergency routing number as the called party number. The switch that routed the emergency call from the mobile station to the PSAP receives the call back. The PSAP also sends the identifier of the mobile station to the switch. When a switch receives its emergency routing number as the called party number, the switch recognizes an emergency call back situation and pages the mobile station identified by the mobile station identifier received in association with the emergency routing number. The mobile station is then reconnected with the PSAP.

Emergency service calls in North America are originated by dialing "9-1-1." Other parts of the world may use some other abbreviated string of dialable digits such as "6-1-1" in Mexico; all share the intent to provide the caller with an easy way to call for help with an easy to remember number. These calls are routed to a local Public Service Answering Point (PSAP) where an emergency response may be initiated (police, fire department, road repair, ambulance, etc.) while the caller is kept on the phone. If the call is somehow disconnected or dropped before the emergency is completely reported or the responder arrives, the PSAP may call back the originator using a call back number provided through its databases.
For example, the call record for a 911 call originated through a wired network may include Automatic Line Identification (ANI) or the telephone number of the access line from which the call originated. However, the mobile directory number (MDN) or telephone number of a wireless subscriber is not associated with a physical line or mobile station. Instead, calls to a wireless subscriber are routed to the mobile station by way of the mobile station identification (MSID), not the MDN. Accordingly, performing an emergency call back to a mobile station poses hurdles not encountered with, e.g., land line devices.
Typically, the MSID is either a 10-digit mobile identification number (MIN) or a 15-digit International Mobile Subscriber Identifier (IMSI) programmed into a mobile station by the service provider with whom the mobile station user has entered into a service agreement. Accordingly, the MSID is not necessarily a dialable number.
The MDN of a mobile station is a dialable number. The MDN is dialed by a caller and used to route a call through the network to the wireless subscriber's home system. At the subscriber's home system, the home location register (HLR) contains the MSID associated with the subscriber's MDN. The MSID, not the MDN, is then used to route the call through the network to the serving wireless system and page the subscriber. The subscriber's MDN is provided by the home system to the serving system in a separate data file called the subscriber profile.
The use of a separate number for MDN and MSID is new to some systems. Historically, in TIA/EIA-41 systems before the implementation of wireless number portability (WNP) or thousands block number pooling (TBNP) based on the Local Routing Number (LRN) method and international roaming (IR), the mobile identification number (MIN) of a mobile station was the same as the MDN. However, with WNP and TBNP, the MDN became "portable" or "poolable" from one service provider to another service provider. Since MSID is not portable or poolable, the recipient service provider assigns a new MSID for a subscriber with a ported-in or pooled MDN.
International roaming also forced the separation of MSID and MDN. While the MIN is a 10-digit number modeled after the North American Numbering Plan's 10-digit MDN, other nation's carriers using a different directory numbering plan may not allow their MDN to be equivalent to the internationally recognized MIN format. Another standard MSID is the IMSI. It is used in both TIA/EIA-41 and GSM systems around the world. IMSI is a 15-digit number, and therefore, can not serve as a 10-digit MDN.
Historically, when the MDN was the same as the MIN, the MIN would be delivered to a PSAP and would be used for a call back number. With the separation of MIN and MDN as described above, it became necessary to deliver the MDN as a separate call back number to the PSAP as well as the caller's MSID. There are certain problems associated with implementing this solution. The primary problem is that the serving system may not have the caller's MDN, only the MSID, to present to the PSAP with the call. Some of the reasons for this relate to the way MSID-MDN separation has been implemented according to standards.
An old serving TIA/EIA-41 system may not support WNP, TBNP or IR. This means that the older serving system may be expecting the MIN and the MDN to be the same. The older system would not even know to look for a separate MDN in the subscriber's service profile (keyed on MIN, not MDN). With this limitation, these subscribers may not be allowed to use basic services, but they must be allowed to call for emergency services. As a result, a roamer who dials "9-1-1" while on an old system will have his or her call delivered to the PSAP with an MSID but no MDN. Accordingly, no call back is possible.
A newer serving system that is WNP and IR capable may not be able to deliver MDN to the PSAP. This could happen if the calling mobile station is not registered with any service provider (e.g., there are mobile phones used for emergency calls only). It is also possible for a subscriber to place an emergency call before the HLR has responded to the serving system with the subscriber's service profile containing the MDN.
The call back MDN for an international roamer would require the PSAP to place an international call to reach a subscriber in their local Emergency Service Zone (ESZ). This is not a practical, timely or sufficiently reliable solution for a PSAP that normally does not place international calls and may require immediate call back information in order to save someone's life. In addition, the entire international MDN (up to 15 digits including a country code) may not be presented to the PSAP for callback.
One proposed solution to these problems calls for delivering 9-1-1+the last 7 digits of the electronic serial number (ESN) of the calling mobile station to the PSAP as the call back number when the MDN is not available. While this may serve to identify the caller to the PSAP and the serving system, this "9-1-1+ESN7" can not be routed through the network and can not be used to place a call back.