A High Bandwidth Individual Channel Control via Optical Reference Interferometry (HICCORI) system actively controls the phase and/or polarization of the optical emission of each element in a tiled optical array. It can also actively align any high-frequency broadening waveform applied to the array beams for spectral broadening or data transmission. By maintaining consistent polarization and manipulating the phase relationships of the beams emitted by the array elements, the HICCORI system can manipulate the spatial pattern of constructive and destructive interference formed as the individual emissions coherently combine. Active feedback control allows the desired phase, polarization, and/or spectral broadening alignment to be maintained in the presence of external disturbances.

A typical coherently combined optical system or optical phased array includes a single laser source whose output is split N ways to seed N individual amplified optical paths. The output of each path is then transmitted, often via fiber, to an individual element in a tiled optical array, which launches the energy into free space. After passing through some number of free space optical components, the energy from the array propagates out of the system.
The emission from each element in the array diverges as it propagates due to diffraction, causing the energy to spread over a relatively large field of regard at some distance. The coherent combination of the emissions from each element over this area can result in a non-uniform distribution of combined optical intensity. Constructive interference occurs at spatial locations where the phases of the elements are well-matched, and destructive interference occurs at spatial locations where the phases of the elements are mismatched, producing an intensity variation in the far field.
Unfortunately, typical coherently combined optical systems employ amplification stages, optical fiber, and optomechanical structures, which cannot maintain a stable optical phase delay or output polarization state. Without an active control system, the phase and polarization of the optical emission of each element in the array changes continuously over time with respect to the phases and polarizations of the other elements in the array. This results in an uncontrolled and ever-changing intensity distribution pattern spread across the entire field of regard as the coherent combination of the emissions transition between various degrees of constructive and destructive interference at each spatial location.
It is typical for an optical phased array system to actively manipulate the phases and polarizations of the N seeds to realize respective changes in the states of the free-space emissions from the elements of the array. A phase modulator with an actuation range of greater than ±π is sufficient for systems employing a sufficiently narrow linewidth seed laser. Within the constraints of the coherence length of the seed, optical phase delays differing by an integer number of full phase revolutions are functionally equivalent.
Certain systems introduce very high-frequency phase change sequences that effectively broaden the linewidth of the seed and reduce the coherence length. Communication systems may employ phase-shift keying for encoding information. Other systems may use repeating spectral broadening waveforms to suppress stimulated Brillouin scattering. These waveforms should align in time at the point of coherent combination by either actively compensating the phase delay in each channel over a large throw or by independently applying an identical waveform to each seed with an adjustable time alignment.
It is possible to increase or maximize constructive interference of the individual emissions so that a significant portion of the total emitted energy focuses into a relatively small high-intensity spot. This can be accomplished by maintaining the phase of the emission of each element in the array at some offset with respect to the phases of the other elements. More generally, phase offsets can be applied to manipulate the wavefront to control tip, tilt, focus, and higher-order Zernike modes, which may facilitate compensation of optical aberrations.
A feedback control system can observe or estimate the current state of the array, determine the desired phase and/or polarization corrections, and apply those corrections to the array elements. The feedback control system's stability and performance can be analyzed using established mathematical methods. One performance metric for the feedback control system is how well it observes and corrects deviations from the desired state due to vibration, thermal changes, and other external factors. In general, increasing the feedback loop bandwidth for each channel improves this disturbance rejection performance.
Predominant existing methods for coherently combined optical array control, including LOCSET (Locking of optical coherence via single-detector electron-frequency tagging) and SD-SPGD (Single detector stochastic parallel gradient decent), use a single feedback signal, which is a surrogate for the on-axis, far-field intensity of the entire array. These control methods work to maximize the on-axis far-field intensity by adjusting each elements phase and polarization to maximize the feedback signal.
FIG. 13 illustrates a coherent beam combining system 1300 that uses a single feedback signal to control the relative phases of the array outputs. The system 1300 includes optics 1310, phase-sensing components 1320, and phase control components 1330. The optics 1310 include a seed laser 1301, such as a fiber laser or other narrow-linewidth source, that emits a seed laser beam. A splitter 1311 divides the power in the seed laser beam into N channels (in FIG. 13, N=4), each of which includes a phase modulator 1312, optical amplifier 1315, and emitting element 1316 (e.g., a collimating lens). Each phase modulator 1312 applies a unique phase dither to its channel.
A beam sampler 1317, such as a bulk optic beam splitter, directs a portion of the beams emitted by the emitting elements 1316 to a lens 1325 that focuses these beam portions on a single-element detector 1326. The intensity detected by the detector 1326 fluctuates with the phase dithers applied to the different channels by the phase modulators 1312 and with environmentally induced phase perturbations. Measurement circuitry 1327 (e.g., a field-programmable gate array (FPGA)) digitally mixes the sampled photodetector output with each dither sequence 1328 and filters the result to produce a phase estimate relating the channel phase to the mean phase of the ensemble. Control circuitry 1331 (e.g., implemented in the same FPGA as the measurement circuitry 1327) calculates the difference between the target phase offset, (typically zero), and the estimate to form an error signal. The control circuitry 1331 drives the corresponding channel phase actuator 1312 in a manner that reduces the magnitude of the error signal.
LOCSET utilizes sinusoidal dithers at unique frequencies, which is a frequency division multiplexing approach to share the feedback signal amongst the elements. SD-SPGD employs orthogonal discrete time periodic sequences for the dither waveforms, which represents a spread-spectrum code division multiplexing approach. The assignment and application of the unique dither waveforms are centrally coordinated across the array.
For LOCSET and SD-SPGD, the dither actuation and the feedback signal bandwidth must each meet or exceed the product of the element count N and the per-element measurement bandwidth required for the application. This leads to challenges for arrays with many elements, as the bandwidth of the hardware components increases linearly with channel count to maintain a given control performance. This increase in bandwidth makes it impractical to control large numbers of elements with a single feedback signal.
In addition, the dithering employed in approaches that use a single feedback signal directly affects the phase alignment of the array, resulting in some loss of combining efficiency. For this reason, the combined amplitude of the dithers must remain sufficiently small. As the channel count is increased, the dither of each individual channel produces a smaller percentage change in the feedback signal. This makes the process of estimating the phase error of each channel increasingly sensitive to noise. As channel count increases, the net spectral noise density in the feedback signal must be reduced proportionally to maintain a constant control performance.
With LOCSET, SD-SPGD, and other approaches based on a single feedback signal for the entire array, the ability to manipulate the phase relationship of the elements of the array is limited by the single on-axis far-field intensity measurement of the feedback signal. As the wavefront is manipulated (e.g., as the location of peak coherent combination is shifted away from optical axis), the feedback signal power drops and the controller can no longer actively maintain the phasing of the array by maximizing the feedback signal. Approaches have been developed which time-interleave periods of on-axis active (closed-loop feedback) phase control with periods of open-loop wavefront manipulation, but these approaches directly impair the ability of the system to suppress the effects of external disturbances.

High bandwidth individual channel control via optical reference interferometry control system architecture


Systems and methods are provided herein for improving the selectivity and productivity of sensors via digital signal processing techniques. According to one illustrative embodiment, in an electrochemical method for monitoring of a select analyte in a mixed sample with an interfering analyte, an improvement is provided that includes applying a large amplitude potential stimulus waveform to the sample to generate a nonlinear current signal; and resolving a signal contribution from the select analyte in the generated signal by a vector projection method with an analyte vector comprising a plurality of real and imaginary parts of one or more Fourier coefficients at one or more frequencies of a reference current signal for the select analyte.

Since their advent in the 1960s, the use of biosensors has become widespread. A biosensor is a device that couples a biological recognition element (e.g., an enzyme or antibody), with a transducer (e.g., an electrode or photodiode), to convert biochemical information into an electric signal.
FIG. 1 shows the action of a glucose biosensor that includes an enzyme coated electrode 1 to which a voltage potential is applied. The biosensor of FIG. 1 is an example of amperometric detection in which a voltage is applied to the electrode 1 which causes a particular analyte (the substance being measured) in the sample to oxidize or (i.e., give up electrons to the electrode). The oxidation cause a current 3 to be generated which can then be detected and analyzed. The potential at which the analyte oxidizes is called the "oxidation potential" of the analyte.
Generally speaking, the term "redox potential" is used to indicate the potential at which an analyte is either oxidized or reduced. In the biosensor of FIG. 1, glucose ("GLU") reacts with the enzyme and transfers electrons to the enzyme, converting it from its oxidized state to its reduced state. Some other electron shuttle (in an oxidized form) reacts with the enzyme to turn it back over to its oxidized state. The electron shuttle then becomes reduced in the process (taking electrons from the reduced enzyme). The reduced electron shuttle is what is oxidized at the electrode. One example of such an electron shuttle is oxygen, being reduced to hydrogen peroxide. There is also a family of electron shuttles called mediators that are used in many commercial glucose test strips that perform this function instead of relying on oxygen.
Using the technique of amperometry, selectivity towards one of several analytes in a sample is achieved by applying the redox potential of that analyte. Thus, in FIG. 1, a sufficiently high potential is being applied to oxidize the reduced electron shuttle, and the resultant current 3 detected by the electrode depends on the concentration of the reduced electron shuttle, which in turn depends on the glucose concentration in the sample. (It should be noted that in actuality a mediator agent associated with the glucose is reoxidized and reacts with the reduced enzyme. The concentration of the reduced mediator is directly indicative of the concentration of glucose in the sample. For the sake of simplicity glucose will be referred to as the analyte being oxidized with the understanding that it is in fact the reduced mediator that is the actual analyte detected at the electrode.)
Electrochemical biosensors are an attractive offering due to their low cost and ease of manufacture, however other blood chemicals, such as ascorbic acid (vitamin C), acetaminophen ("TYL" in FIG. 1), and uric acid can interfere with the biosensor action resulting in erroneous readings. FIG. 1 shows the effect of the interferent ascorbic acid ("C"), in which a molecule of ascorbic acid 5 has diffused through the enzyme layer, been directly oxidized by the electrode 1, and generated a current 7.
Thus, when a sample contains several analytes, all with overlapping redox potentials (that is, where the redox potentials of several analytes are within the same ranges and thus all give rise to a redox current at the same applied electrode potential), the selectivity of the electrode diminishes. The current generated at the electrode results from all analytes from the sample that can be electro-oxidized or electro-reduced at the given electrode potential, resulting in a sensed current that includes unknown components of each analyte, thereby resulting in diminished electrode selectivity and incorrect concentration readings. Testing for an analyte without accounting for analytes with overlapping redox potentials will result in inaccurate readings.
FIGS. 2–4 graphically illustrate the foregoing problem, with respect to hydrogen peroxide (the target analyte) and ascorbic acid (the interferent). As shown in FIGS. 2 and 3, increasing amounts of each of ascorbic acid and hydrogen peroxide (x-axis) when applied with the same DC amperometric voltage of 600 mV generate an increase in the sensed current (y-axis). Calibration curves 9 and 11 are determined from current readings 13 and 15, respectively.
Because the redox potentials overlap at 600 mV, false readings result as shown in FIG. 4, when testing for hydrogen peroxide. The tester should read a concentration of 1 mM, as indicated by dashed line 17. The tester instead falsely generates readings 19 showing increasing amounts of hydrogen peroxide when in fact increasing amounts of ascorbic acid are added to the measured sample containing a constant amount of hydrogen peroxide.
Other interferences that commonly plague biosensors include cross-reactivity with other sample components, physical deterioration or fouling of the sensor, or background noise. Efforts to overcome the foregoing shortcomings of biosensors have traditionally been to use physical or chemical enhancements to the device such as using chemical mediators or perm-selective membranes. However, mediators can contribute to increased background noise and membranes add unnecessary production costs while reducing the sensor's overall sensitivity.

Method and apparatus for processing electrochemical signals


An image enhancer that includes a laser for emitting an optical signal toward an object in a turbid medium, a modulator for modulating laser intensity of the optical signal, an RF source for driving the modulator and for providing a reference signal, an optical detector for detecting the modulated optical signal that is reflected from the object, the optical detector converting the reflected optical signal into an electrical signal, the electrical signal having RF and DC components, an I/Q demodulator for mixing the RF component of the electrical signal with the reference signal and producing in-phase and quadrature phase signal components that can be digitized and processed such that both contrast and range images of the object are produced.

The present invention relates to an image enhancer for detecting and identifying objects in turbid media. More specifically, but without limitation, the present invention relates to a laser system that can detect and identify objects in turbid media.
Laser systems have been and are continuing to be developed to detect and identify objects in turbid media (examples of turbid media include, but without limitation, seawater, clouds, and tissue). Operating a laser imaging system in such an environment is challenging due to the fact that light is both absorbed and scattered. Although the optical wavelength is typically selected to minimize absorption, the scattering experienced by an optical signal can severely degrade image quality. In highly turbid media, there may be plenty of light scattered back from the object of interest, but it is buried in the signal returning from the surrounding environment. A method for separating the unscattered (or minimally scattered) image bearing photons from the scattered, background light can be used to improve object detection and identification.
Several techniques have been developed for reducing the detrimental effects of scattered light. These approaches can be categorized according to the type of laser source and receiver combination and the scanning method used to create the image. All these types of systems are capable of creating an image, whether it is a synchronously scanned narrow beam and a narrow receiver field of view (narrow-narrow) or a flood-illuminated scene with a multiple pixel receiver (wide-narrow). The decision as to which configuration provides the best performance depends directly on the task at hand (i.e., above-water or below-water operation, size and depth of underwater object, water optical properties, etc.).
One type of known system is the Laser Line Scan (LLS) system. The Laser Line Scan (LLS) system includes a well-collimated continuous wave source and a narrow field of view receiver that are synchronously scanned over the object of interest. The bistatic configuration limits the common volume created by the source and receiver field of view overlap and reduces the contribution from scattered light. However, since the system uses a continuous wave source, no inherent time (depth) information is present in the detected signal, and post-processing using triangulation methods must be used to obtain object range information.
Pulsed laser sources are also used in several underwater laser-imaging systems to temporally discriminate against scattered light and to provide object range information. In the operation of a typical range-gated imaging system, a short (10-20 nsec) pulse is transmitted to a distant object, and the receiver is timed to open only when the reflected light returns from the object. A typical configuration is broad-beam illumination of the scene and a gated intensified camera receiver, although systems using photomultiplier tube receivers in both single and multiple pixel configurations have also been utilized. The Streak Tube Imaging Lidar (STIL) uses a pulsed laser transmitter in a 'scannerless' configuration. Instead of scanning the laser beam, a fan of light is used to illuminate a volume of water. The streak tube receiver can measure both the amplitude and range (time) of the collected slit of light, and a three-dimensional image is created when the system is operated from a moving platform. While the range-gated and STIL approaches are effective in minimizing background light, the sensitivity is ultimately limited by small-angle forward scattered light that induces image blurring.
Another type of underwater imager encompasses those that use temporal modulation of the transmitted light and subsequent synchronous detection of the modulation envelope at the receiver. The Underwater Scannerless Range Imager (USRI) uses a radio frequency modulation source that is coupled to both the timing of the laser transmitter and the gain of the image intensified CCD receiver. Object range information is obtained by measuring the phase difference between the transmitted and reflected signals simultaneously for each pixel of the receiver. However, multiple frames are required using different modulation schemes in order to extract the range information and to differentiate changes due to range variations from those due to intensity variations in the scene. Previous configurations used continuous wave sources, but a recent configuration implements a pulsed source and a range-gated receiver to minimize the volumetric backscatter signal.
Researchers at the Naval Air Systems Command (NAVAIR) are also developing a system that uses temporal modulation of the transmitted optical signal. However, in this approach, the optical receiver consists of a photodetector with sufficient bandwidth to recover the modulation envelope encoded on the optical signal. The resulting radio frequency signal is then processed using traditional radar signal processing techniques. This approach reduces the contribution by volumetric backscatter by using a modulation frequency that becomes strongly decorrelated with respect to the transmitted signal due to multiple scattering. A gain in image contrast is achieved when the modulation envelope emanating from an underwater object remains coherent relative to the original modulation signal. The phase information encoded on the detected modulation signal is processed to obtain object range information.
In previous embodiments of this modulated imaging system approach, a spectrum analyzer was used to produce the signal and the system produced a so-called "magnitude" image that was shown to have a nonlinear dependence on the object albedo (the term albedo may be defined, but without limitation, as ratio of the amount of electromagnetic energy reflected by a surface to the amount of energy incident upon it or the fraction of radiation striking a surface that is reflected by that surface). This non-linearity created a variety of sometimes unexpected features, such as contrast inversion, appearance of false elements in the image patterns, and the "emphasizing of the outlines" in object albedo patterns. In this system configuration, the irradiance distribution in the image plane is not proportional to the actual reflectivity of the object, the image is distorted, and its identification is difficult if impossible. This non-linearity is the main drawback of the conventional "magnitude" signal registration of previous system configurations.
For the foregoing reasons, there is a need for an image enhancer for detecting and identifying objects in turbid media.

Image enhancer for detecting and identifying objects in turbid media

The United States of America as represented by the Secretary of the Navy


By evaluating a distance starting from a start point to a unit on the map, the strength of an enemy character to be encountered, the degree of difficulty for an object to pass through a gate, etc., a unit score is calculated for each route. This unit score can be taken as an index of the degree of difficulty for the object to arrive at a unit from the start point. By using this unit score, the game elements can be appropriately disposed on the map in accordance with the degree of difficulty.

Conventionally, various games have been developed in which a player object operated by a player is moved on a map. On the map, additional game elements (items, enemy characters, doors, a start point, a goal point, and the like) are disposed. With these game elements being not fixedly but changeably disposed, variety is added to the map, thereby allowing the game to proceed without making the user weary of the game. For example, in a conventional game machine as disclosed in Japanese Patent Laid-Open Publication No. 2000-107441, such game elements are randomly disposed on the map.
In the game machine disclosed in the in Japanese Patent Laid-Open Publication No. 2000-107441, the game elements, such as enemy elements and items, are randomly disposed on the map. Specifically, a memory of the game machine has stored, in its fixed area having a predetermined shape and size, a plurality of maps which form different patterns of terrains in the whole area. A game machine computer selects one map in accordance with the degree of difficulty of the game, and then randomly disposes the above game elements on the map. With this, it is possible to obtain a map having the game elements being differently disposed every time the game is played.
In the above-described conventional game machine, the game elements, such as the enemy characters and other items, are randomly disposed. Therefore, the game elements are not necessarily disposed at positions appropriate for the progress of the game. For example, when the random process disposes many items or an important enemy character at the start point on the generated map, the enjoyment of playing the game on the map is quickly satisfied in the vicinity of the start point, thereby making the game less entertaining. Moreover, when there are a plurality of routes to the destination on the map, the degrees of difficulty of these routes do not depend on how the game elements are disposed on each route, and therefore the player may easily arrive at the destination through the selected route.
Exemplary illustrative non-limiting implementations herein provide a game machine and a data storage medium having a game program stored therein allowing additional game elements to be not fixedly but changeably disposed at an appropriate position on a map.
The exemplary illustrative non-limiting implementation has the following features to attain the object mentioned above:                calculating a unit score for each of the units, the unit score being determined based on route information regarding a route starting from a start unit serving as a start point on the game map to each unit;        selecting, based on the unit score calculated in the unit score calculating step, a unit on which the game element is disposed; and        disposing the game element on the unit selected in the disposition unit selecting step.
A first aspect of an exemplary illustrative non-limiting implementation is directed to a game machine for disposing an additional game element (an enemy character, a gate, an item, a goal point) on a game map formed by a plurality of units (which exemplarily corresponds to, in the preferred exemplary illustrative non-limiting arrangement, a room unit RU, a passage unit PU, a cap unit CU). The game machine includes: unit score calculating means (which exemplarily corresponds to, in the preferred exemplary illustrative non-limiting arrangement, a CPU 31 steps executing S82, S86, and S94; only step numbers are hereinafter shown), disposition unit selecting means (S84, S91, S99, S104), and game element disposition means (S84, S91, S99, S104). The unit score calculating means calculates a unit score for each of the units, the unit score being determined based on route information regarding a route (route distance, the number and type of an enemy character located on the route, the number and type of a gate located on the route) starting from a start unit serving as a start point on the game map to each unit. The disposition unit selecting means selects a unit on which the game element is disposed, based on the unit score calculated by the unit score calculating mean. The game element disposing means disposes the game element on the unit selected by the disposition unit selecting means. Note that the game machine may further include start unit determining means which determines the start unit including the start point on this map. Also, in the game machine, the unit score may be determined in consideration of, in addition to the information regarding the route to the relevant unit, information regarding the inside of the unit (the number and type of enemy characters, for example). Furthermore, if the unit score of the start unit is calculated, although not necessarily required, one exemplary scheme used for calculation is based on the game elements located in the start unit. In this case, the unit score may be set higher as the number of enemy characters is larger. Alternatively, the unit score may be set higher as the strength of the enemy character is higher. In another calculation scheme, the unit score of the start unit may be set to a predetermined value (0, for example).
According to the above configuration of the exemplary illustrative non-limiting implementation, the unit score is calculated based on the information regarding the route from the start point on the game map to each unit. By using the route distance, the number and type of the enemy characters located on the route, the number and type of the gates located on the route, etc., as the route information, it is possible to cause the unit score to indicate the degree of difficulty for the player character or the like to arrive at the unit. Also, by using the number and type of the items located on the route, etc., as the route information, it is possible to cause the unit score to indicate the merit obtained until the player character or the like arrives at the unit. Then, by using the unit score, a game element is additionally disposed on the game map. Therefore, the game element can be appropriately disposed in accordance with the degree of difficulty or the merit. For example, when the unit score indicates the degree of difficulty, the following examples can be thought. That is, in order to set a precious item to be difficult for the player to obtain, the precious item may be disposed on a unit having a high unit score. Also, an item supporting the player may be disposed on a unit having a high unit score. Furthermore, a goal point may be set in a unit having the highest unit score. Still further, a weak enemy character may be disposed on a unit having a low unit score, while a strong enemy character may be disposed on a unit having a high unit score. Still further, when the unit score indicates the merit, a strong enemy character may be disposed on a unit having a high unit score, for example. These are merely examples, and the unit score may be used in various manners depending on the contents of the game and the intention of the game designer. By contrast to the above examples, depending on the contents of the game, a precious item may be disposed on a unit having a lower unit score, or a game element may be disposed on a unit having an intermediate unit score. As described above, although the unit score indicates the degree of difficulty or the merit, description is hereinafter made mainly to a case where the unit score indicates the degree of difficulty. The same description goes for the case where the unit score indicates the merit.
By way of example only, the unit score calculating means calculates a distance parameter for each of the units as the unit score, the distance parameter being indicative of a distance of the route starting from the start unit to each unit. With this, as the distance from the start point to a unit is longer, it is more difficult for the object to arrive at that unit. Therefore, by calculating a distance parameter indicative of the distance, the unit score representing the degree of difficulty by the distance can be obtained. Then, based on the distance parameter, a game element is disposed. Therefore, the game element can be appropriately disposed in consideration of the entertainment aspect of the game. For example, a game element, such as a goal point, the most important enemy character, an item, etc., which is preferably disposed on the unit farther away from the start point, can be appropriately disposed in accordance with the distance from the start point. For example, each of the units includes at least one connecting portion (door DR) for connection to another unit, and with the connecting portion being connected to another connecting portion of the other unit, the units are combined to form the game map. In this case, the game machine may further include connecting portion distance data defining means (a unit storage area 322 storing the door-to-door distance table). The connecting portion distance data defining means defines connecting portion distance data (door-to-door distance data) indicative of a distance between the connecting portions in a unit having a plurality of the connecting portions. The unit score calculating means calculates the distance parameter by totaling the connecting portion distance data for connecting portions to be passed through on the route starting from the start unit to each unit. With this, the distance parameter can be appropriately and easily calculated.
In another example, the unit score calculating means calculates the unit score based on game elements located in a unit to be passed through on the route starting from the start unit to each unit. With this, as the unit has more game elements serving as obstacles, such as enemy characters and doors, which the object, such as the player character, encounters on a route from the start point to one unit, it is more difficult to arrive at that unit. Therefore, the unit score representing the degree of difficulty by the obstacle can be obtained. Also, as the unit has more game elements, such as town people characters, which the object encounters on a route from the start point to one unit and which give the object an item or a hint, the merit of arriving at that unit is larger. Therefore, the unit score representing the merit can be obtained. Then, based on the unit score indicative of the degree of difficulty or the merit, the game element is disposed. Therefore, the game element can be appropriately disposed in consideration of the entertainment aspect of the game. For example, a game element, such as a goal point or the most important item, that is preferably disposed on the unit at which the object arrives from the start point after clearing many obstacles can be appropriately disposed based on the obstacles on the route from the start point. Also, the game machine may further include attribute value setting means. The attribute value setting means sets a unique attribute value (the strength of the enemy, the strength of the gate) based on a type of each of the game elements. The unit score calculating means calculates the unit score based on the attribute value set to each of the game elements located in the unit to be passed through. With this, when the object encounters the enemy character, which is a game element, while traveling from the start point, the strength of the enemy character, etc., will have an influence on the degree of difficulty in arriving at the unit. Since the unit score is set in consideration of the attribute value of the strength of the enemy character, the unit score more accurately indicative of the degree of difficulty can be set. Also, for example, if the unit score is set in consideration of the effectiveness of the item, the unit score accurately indicative of the merit can be set.
For example, each of the units includes at least one connecting portion for connection to another unit, and with the connecting portion being connected to another connecting portion of the other unit, the units are combined to form the game map. In this case, the game machine may further include connecting portion score calculating means (S825, S826, S830). The connecting portion score calculating means calculates, for each connecting portion, a connecting portion score (door score) determined based on route information regarding a route from the start unit to each connecting unit. The unit score calculating means calculates the unit score for each of the units based on the connecting portion score calculated for the connecting portion included in a relevant unit (S828). With this, in consideration of the connecting portion serving as an entrance or exit of each unit, the connecting portion score indicative of the degree of difficulty or the merit for the object to travel from the start point to that connecting portion can be calculated. Then, the unit score of the unit including the connecting unit is calculated with the connecting portion score. Therefore, each unit score can be appropriately and easily obtained. Furthermore, the unit score calculating means may calculate the unit score for a unit which includes a plurality of the connecting portions based on a minimum value of the connecting unit scores calculated for the connecting portions (S825 through S828). In this case, the unit score of the unit including the connecting portion is calculated with the minimum value of the connecting portion score. Therefore, the unit score obtained when the object travels from the start point to each unit with a lowest degree of difficulty and the easiest travel can be appropriately and easily obtained. Still further, start unit connecting portion score temporarily-setting means may be provided, which calculates the connecting portion score for each of the connecting portions included in the start unit through a predetermined calculation scheme and temporarily sets the calculated connecting portion score. Here, the predetermined calculation scheme is, for example, a scheme based on the game element located in the start unit. In this case, the connecting portion score is set higher as the number of enemy characters located in the start unit is larger (or as the strength of the enemy characters is larger) or when a gate is set in that connecting portion included in the start unit. In another exemplary calculation scheme, a predetermined value (0, for example) may be set to all connecting portions included in the start unit. Still further, the unit score calculating means may include: minimum connecting portion score determining means (S825), the coupled connecting portion score determining means (S826), and connecting portion score temporarily-setting means (S830). The minimum connecting portion score determining means determines a minimum value of the connecting portion scores temporarily set to the connecting portions as the connecting portion score of a connecting portion having the minimum value. The coupled connecting portion score determining means determines the minimum value as the connecting portion score of a connecting portion coupled to the connecting portion whose connecting portion score has been determined by the minimum connecting portion score determining means. The connecting portion score temporarily-setting means calculates a connecting portion score for a first connecting portion whose connecting portion score has not yet been determined and temporarily sets the calculated connecting portion score, the first connecting portion being included in a unit which also includes a second connecting portion whose connecting portion score has been determined by the minimum connecting portion score determining section or the coupled connecting portion score determining section, and the connecting portion score for the first connecting portion being calculated based on route information regarding a route from the second connecting portion to the first connecting portion included in the unit (S830). With a repeat of processes performed by the minimum score determining means, the coupled connecting portion score determining means, and the connecting portion score temporarily-setting means (a repeat of steps S825 through S830), the unit score calculating means sequentially determines connecting portion scores of the connecting portions on the game map, and calculates the unit score based on the determined connecting portion scores (S828). With this, the minimum connecting portion score is determined with priority by taking the connecting portion score of the start unit in which the start point is set as a starting point. Also, based on the determined connecting portion score, the unit score is also determined. Therefore, to all units and connecting portions formed on the game map, it is possible to reliably calculate their unit scores and connecting portion scores by using the lowest degree of difficulty for the object to arrive from the start unit.
The disposition unit selecting means may select the unit on which the game element is disposed so that a ratio of a unit score of one unit with respect to a total of the unit scores is equal to a probability of selecting the one unit (S96 through S99). With this, each degree of difficulty for the object to arrive at each unit from the starting point is evaluated with respect to the entire degree of difficulty, and based on the evaluation, the game element can be disposed. For example, a game element can be reliably disposed with priority on the unit having a relatively high or the highest degree of difficulty. With this, a game element, such as a goal point or the most important item, that is preferably disposed on the unit at which the object arrives with difficulty after traveling from the start point can be appropriately disposed. Also, if a unit is selected based on a ratio of the degree of difficulty with respect to the entire degree of difficulty, as the unit has a higher degree of difficulty, the ratio of disposing a game element on that unit can be higher.
The disposition unit selecting means may include transformed unit score calculating means (S88, S96, S101). The transformed unit score calculating means calculates a transformed unit score (Tx) by transforming the unit score calculated by the unit score calculating means through a predetermined function (Scmax+Scmin−Sc(Ux) or the positive square root of Sc(Ux)). The disposition unit selecting means selects the unit on which the game element is disposed so that a ratio of a unit score of one unit with respect to a total of the unit scores is equal to a probability of selecting the one unit (S88 through S91 or S101 through S104). Thus, the unit score is transformed by using the predetermined function, and then the transformed unit score is used. With the function being appropriately set, the game elements can be disposed in various manners. For example, the unit having a lower degree of difficulty is prioritized for disposition. Alternatively, the unit having a higher degree of difficulty is prioritized for disposition but its degree of priority is reduced or increased. For example, the function used by the transformed unit score calculating means is varied depending on a type of the game element to be disposed by the game element disposing means. With this, it is possible to control the disposition point of the game element by the function depending on the type of the game element. Here, various types of game elements can be thought. For example, a goal point may be of a type not necessarily required to be disposed on a unit having a high degree of difficulty, and an obstacle may be of a type desired to be disposed on a unit having a low degree of difficulty. By selecting the function in accordance with the type of the game element, it is possible to balance between randomness of disposition of the game elements and units to be disposed.
Also, the disposition unit selecting means may include: random number generating means (S90, S98, S103) and range assigning means (FIG. 25). The random number generating means generates a random number in a predetermined range. The range assigning means assigns a part of the predetermined range to each of the units based on a ratio of each unit score with respect to the total of the unit scores or a ratio of each unit score with respect to a total of the transformed unit scores. The disposition unit selecting means selects the unit on which the game element is disposed depending on whether the random number generated by the random number generating means is within the part of the range assigned to the unit by the range assigning means.
For example, the game map include at least a unit including a point (start slot Ss, goal slot Sg, enemy slot Se, item slot Si) at which the game element can be disposed. In this case, the disposition unit selecting means may include: random number generating means and range assigning means (FIG. 28). The random number generating means generates a random number within a predetermined range. The range assigning means sets the unit score of the unit including the point as a point score of the point, and assigns a part of the predetermined range to each of a plurality of the points based on a ratio of each point score with respect to a total of point scores or a ratio of each point score transformed through a predetermined function with respect to a total of the transformed point scores. The disposition unit selecting means selects a point where the game element is disposed depending on whether the random number generated by the random number generating means is within the part of the range assigned to the point by the range assigning means. With this, a game element can be appropriately disposed at a point in the unit.
The game machine may further includes unit storage means (unit storage area 322 for storing a unit image data group) and game map generating means (S1 through S7). The unit storage means stores in advance the plurality of the units. The game map generating means generates the game map by randomly combining the units stored in the unit storage means. With this, effects similar to those of the first aspect of the exemplary illustrative non-limiting implementation can be obtained also for the automatically-generated game map full of diversity. Also, by combining the diversity in disposition of the game element with the diversity of the game map itself, a game map full of variation can be generated.
A second aspect of the exemplary illustrative non-limiting implementation is directed to a game machine for disposing an additional game element on a game map which is formed by a plurality of units and defines an area in which an object can move in the course of a game. The game machine includes: unit score calculating means, disposition unit selecting means, and disposition unit selecting means. The unit score calculating means calculates a unit score for each of the units, the unit score being a parameter indicative of a degree of difficulty for the object to move from a start unit serving as a start point on the game map to each unit. The disposition unit selecting means selects, based on the unit score calculated by the unit score calculating means, a unit on which the game element is disposed. The game element disposing means disposes the game element on the unit selected by the disposition unit selecting means.
According to the above configuration of the exemplary illustrative non-limiting implementation, the unit score is calculated in accordance with the degree of difficulty for the object to move to each unit. By using this unit score, a game element is additionally disposed on the game map. Therefore, the game element can be appropriately disposed in accordance with the degree of difficulty.
A third aspect of the exemplary illustrative non-limiting implementation is directed to a data storage medium having stored therein a game program causing a computer to execute a process of disposing an additional game element on a game map formed by a plurality of units. The game program stored in the data storage medium includes the steps of: a unit score calculating step (S82, S86, S94), a disposition unit selecting step (S84, S91, S99, S104), and a game element disposing step (S84, S91, S99, S104). In the unit score calculating step, a unit score is calculated for each of the units, the unit score being determined based on route information regarding a route starting from a start unit serving as a start point on the game map to each unit. In the disposition unit selecting step, a unit on which the game element is disposed is selected based on the unit score calculated in the unit score calculating step. In the game element disposing step, the game element is disposed on the unit selected in the disposition unit selecting step. With this, effects similar to those obtained by the above game machine can be obtained also by the computer executing the game program recorded on the recording medium.
By way of example only, in the unit score calculating step, a distance parameter is calculated for each of the units as the unit score, the distance parameter being indicative of a distance of the route starting from the start unit to each unit. In another example, in the unit score calculating step, the unit score is calculated based on game elements located in the unit to be passed through on the route starting from the start unit to each unit. For example, each of the units includes at least one connecting portion for connection to another unit, and with the connecting portion being connected to another connecting portion of the other unit, the units are combined to form the game map. In this case, the game program stored in the data storage medium may further include a start unit connecting portion score temporarily-setting step (S824). In this step, a connecting portion score is calculated for each of connecting portions included in the start unit through a predetermined calculation scheme, and the calculated connecting portion score is temporarily set. Also, the unit score calculating step includes a minimum connecting portion score determining step (S825), a coupled connecting portion score determining step (S826), and a connecting portion score temporarily-setting step (S830). In the minimum connecting portion score determining step, a minimum value of the connecting portion scores temporarily set to the connecting portions is determined as the connecting portion score of a connecting portion having the minimum value. In the coupled connecting portion score determining step, the minimum value is determined as the connecting portion score of a connecting portion coupled to the connecting portion whose connecting portion score has been determined in the minimum connecting portion score determining step. In the connecting portion score temporarily-setting step, a connecting portion score is calculated for a first connecting portion whose connecting portion score has not yet been determined and is temporarily set. The first connecting portion is included in a unit which also includes a second connecting portion whose connecting portion score has been determined in the minimum connecting portion score determining step or in the coupled connecting portion score determining step, and the connecting portion score for the first connecting portion is calculated based on route information regarding a route from the second connecting portion to the first connecting portion included in the unit. In the unit score calculating step, with a repeat of the minimum score determining step, the coupled connecting portion score determining step, and the connecting portion score temporarily-setting step, connecting portion scores of the connecting portions on the game map are sequentially determined, and the unit score is calculated based on the determined connecting portion score.
By way of example only, in the disposition unit selecting step, the unit on which the game element may be disposed is selected so that a ratio of a unit score of one unit with respect to a total of the unit scores is equal to a probability of selecting the one unit.
In another example, the disposition unit selecting step includes the steps of: a random number generating step and a range assigning step. In the random number generating step, a random number is generated in a predetermined range. In the range assigning step, a part of the predetermined range is assigned to each of the units based on a ratio of each unit score with respect to a total of the unit scores or a ratio of each unit score calculated in the unit score calculating step and then transformed through a predetermined function with respect to a total of the transformed unit scores. In the disposition unit selecting step, the unit on which the game element is disposed is selected depending on whether the random number generated in the random number generating step is within the part of the range assigned to the unit in the range assigning step.

Multi-user method and apparatus for placing game elements on a map based on degree of difficulty


A post guard system, comprising a guard sleeve attached to a base portion of a fence type post, the guard sleeve composed of a front panel with a front right lateral edge, a front left lateral edge, a right side panel extending at ninety degrees from the front right lateral edge and a left side panel extending at ninety degrees from the front left lateral edge. The front panel dimensioned to cover fully the width of a front or back face of the fence type post at the bottom portion, the front right lateral edge and the front left lateral edge each having a rounded surface that cover an edge of the fence type post at the bottom portion and the right side panel. The left side panel each dimensioned to cover approximately half the width of a side face of the fence type post at the bottom portion.

This invention relates generally to post for fences and other exterior objects needing a fence type post and, more particularly, to a durable sleeve for covering the base portion of a less durable post element such as a fence type post made of metal, vinyl or wood.
A typical fence consists of elements such as pickets, rails and posts made of varying materials such as metal, vinyl and wood and which are quite smoothly finished in order to present a pleasing appearance. The fence elements are generally painted or treated further to improve their appearance and also to protect them from weathering and rotting from the effects of rain, sunshine, wind, fungus and other conditions. Similarly, mail boxes or street signs often include a fence type post element.
One portion of the fence type post element that is particularly vulnerable is the base portion of the fence type post element. This is irrespective of the material from which the fence type post element is fabricated or of the application of any protective coatings that have been applied to the fence type post element. The base portion of the fence type post element has clearly become the most vulnerable component of a fence as a result of the advent of powered weed and grass trimmers.
The powered weed and grass trimmers has made the tedious task of trimming weeds and grass much easier. Powered trimmers spin a hard nylon cord at high speeds to cut grass and weeds and have all but replaced the use of long-handled scissors. A powered trimmer may spin its nylon cord at high speeds anywhere between 7500 RPMs and 11000 RPMs. Moreover, some powered trimmers use a steel line rather than a nylon cord for even greater power and efficiency.
However, the power and efficiency of powered trimmers comes at a cost when it comes to trimming grass and weeds along and surrounding fence type post element. A trimmer's spinning nylon cord or steel line can cause extensive damage to the base portion of a fence type post element as it trims the area surrounding each fence type post element. The nylon cord or steel line hitting up against a fence type post will eat away at the fence type post's pressure treating, paint or stain eventually leaving the fence type post without any of its original protective coatings. Moreover, even costlier fence type post elements fabricated from durable materials, such as steel, will scratch and deteriorate over time from continued exposure to the effects of a powered trimmer. As a result, irrespective of how durable a fence type post element is when initially installed, the base portion of that fence type post element may eventually deteriorate and become fully exposed to surrounding environmental elements as a result of prolonged exposure to the effects of a power trimmer.
Moreover, a related problem has to do with damage done to the nylon cord or steel line of the powered trimmer. The nylon cords and steel lines of a powered trimmer are prone to damage as a result of their hitting against and wrapping around the right angles of a square or rectangular shaped fence type post element at the high speeds of rotation used during normal operation.
Thus there is a need for a durable and inexpensive fence element which also presents a pleasing appearance and which may be easily installed on a new or existing fence type post elements in order to protection to both the base portion of a fence type post element as well as the nylon cord or steel line of a powered trimmer.


An apparatus comprising one or more stations. Each of the one or more stations may be configured to receive a signal from a communication channel. The signal generally comprising event detection information. The one or more stations may be configured to share the event detection information.

A conventional approach for implementing a communication protocol is shown in the circuit 10 of FIG. 1. The circuit 10 illustrates a protocol using a channel for the transmission of electrical signals. The circuit 10 comprises a number of stations 12a–12n. A station is defined as an entity capable of transmitting/receiving information, detecting an external event and acting upon the event (i.e., performing a communication protocol) The circuit 10 also has a first communication channel 14 and a second communication channel 16. Each one of the stations 12a–12n has an input 18a–18n that receives a local event signal LOCALa–LOCALn. The stations 12a–12n are configured to detect a local event on each respective local event line LOCALa–LOCALn. The stations 12a–12n present a signal on the first and second communication channels 14 and 16 in response to the local events LOCALa–LOCALn. Additionally, one of the communication channels 14 or 16 contains information about a first local event detected. The other one of the communication channels 14 or 16 contains information about a last local event detected.
The communication channel 14 performs a wired-NOR function, thereby carrying information about the detection of the first event. The second communication channel 16 performs a wired-AND function, thus carrying information about the detection of the last event.
The disadvantage of such a conventional method is the use of the multiple shared communication channels 14 and 16. The circuit 10 typically requires additional hardware resources to implement the two communications channels 14 and 16. The additional hardware resources are required in order for the communication protocol 10 to function properly.

Communication protocol for the broadcast of first/last event detection over a single communication channel


In a digital information processing system wherein a model of a finite state machine (FSM) receiving a plurality of FSM inputs and producing a plurality of FSM outputs is represented by a reduced-state trellis and wherein the FSM inputs are defined on a base closed set of symbols, a novel method is presented for updating soft decision information on the FSM inputs into higher confidence information whereby (1) the soft decision information is inputted in a first index set, (2) a forward recursion is processed on the input soft decision information based on the reduced-state trellis representation to produce forward state metrics, (3) a backward recursion is processed on the input soft decision information based on the reduced-state trellis representation to produce backward state metrics, wherein the backward recursion is independent of the forward recursion and (4) the forward state metrics and the backward state metrics are operated on to produce the higher confidence information.

Currently, there is great interest in soft-input/soft-output (SISO) algorithms due to the outstanding performance of iterative data detection. Like the Viterbi algorithm (VA), the SISO algorithm is derived for an embedded system that can be modeled as a finite state machine (FSM). However, instead of making hard decisions as does the VA, the SISO algorithm generates soft decisions, i.e., reliability measures, for the investigated data. A hard decision can be readily obtained by thresholding the soft information. The key notion carried with the soft information, also its main advantage over a hard decision, is that the soft information can be refined by some way (e.g., through iteration) to make a later hard decision more reliable. Thus, the SISO algorithm is especially well-suited for iterative data detection. Because of this advantage, SISO algorithms have been widely used in various application, such as decoding of (both serial and parallel) Turbo codes and other codes, near-capacity multi-user detection, near-optimal two-dimensional data detection, and the detection of TCM signals in fading channels.
The biggest obstacle facing a practical implementation of the SISO algorithm is probably its complexity. The complexity of a SISO algorithm grows exponentially with the memory length of the FSM, e.g., the number of taps in an inter-symbol interference (ISI) channel or the constraint length of a convolutional code. It is not difficult to imagine how the complexity of such an algorithm can quickly overwhelm even the most advanced signal processing hardware and software. For a fixed-interval minimum sequence metric (FI-MSM) SISO algorithm, its computational complexity is approximately twice that of the VA and the number of memory units required is proportional to the product of block length and the number of states of the FSM. For instance, when the FI-MSM algorithm is applied to a 10-tap ISI channel with QPSK signaling, its complexity is dominated by the number of the states of the FSM, which is the order of the modulation scheme raised to an exponential equal the number of taps minus one (49=262,144). This relatively simple example of a transmitter and channel thus presents an implementation nightmare, as the relevant signal processing system is asked to perform SISO computations based on 262,144 possible states, a task that is practically infeasible today for most applications.
Therefore, there is a need for a method of digital information processing for producing soft outputs based on soft inputs that offers a significant reduction in computational and memory complexity from the standard SISO algorithm but is still capable of excellent performance.

Method for iterative and non-iterative data detection using reduced-state soft-input/soft-output algorithms for complexity reduction


An image forming apparatus includes an image carrier, a charging device configured to uniformly charge a surface of the image carrier with a charging member applied with a bias of a first polarity (e.g. a negative polarity) for charging. A latent image forming device forms a latent image on the surface of the image carrier uniformly charged. A developing device develops a latent image by depositing toner grains of the first polarity on the latent image to thereby form a corresponding toner image. A transferring device forms an electric field between the image carrier and a moving member that serves as a movable contact with the image carrier to thereby transfer the toner image from the surface of the image carrier to the moving member or to a recording member nipped between the image carrier and the moving member. A polarity controlling device sets residual toner to a second polarity (e.g. a positive polarity) opposite to the first polarity, before the residual toner left on the image carrier by the transferring device is conveyed to a corresponding position to the charging member.

1. Field of the Invention
The present invention relates to a copier, printer, facsimile apparatus, or similar image forming apparatus, and more specifically to an image forming apparatus with an improved cleaning operation and mechanism.
2. Description of the Background Art
An image forming apparatus of the type using an electrostatic image transfer system is known and is configured to form an electric field between a photoconductive drum or similar image carrier and an intermediate image transfer body, sheet conveyor, or similar moving member for thereby transferring a toner image formed on the image carrier. In that type of image forming apparatus, some residual toner is left on the image carrier after the transfer of the toner image to a subject body, e.g., after transfer to the intermediate image transfer body or to a sheet or recording member. If part of the image carrier on which such residual toner is present is subject to the next image formation, then irregular charging or similar defective charging can occur on the noted part of the image carrier, which lowers image quality. It is a common practice to remove the residual toner from the image carrier with a cleaning device. The problem with such a cleaning device is that it needs an extra space for accommodating a waste toner tank configured to store the residual toner collected from the image carrier and a recycling path along which the residual toner is conveyed to be reused, making the entire apparatus bulky. Particularly, a current trend in the imaging art is toward a tandem image forming apparatus that assigns a particular image carrier to each color to meet the increasing demand for high-speed color image formation. If a cleaning device is utilized in this kind of image forming apparatus, then a particular cleaning device must be assigned to each of a plurality of image carriers, making the above problem more serious.
To solve the problem stated above, Japanese Patent No. 3,091,323 discloses an image forming apparatus using a simultaneous developing and cleaning system that causes a developing device to also collect residual toner. More specifically, the developing device, first used to develop a latent image, is also used as a cleaning device at the same time, so that a particular cleaning device does not have to be assigned to each image carrier. This contributes a great deal to the size reduction of the apparatus.
Also, the image forming apparatus disclosed in Japanese Laid-open publication No. 2000-181200 includes a toner removing structure to remove toner from charging device after the charging device charges an image carrier. The charging device deposits polarity control grains, by which the polarity of toner grains is changed to a same polarity as the image carrier. According to this publication, residual toner having an opposite polarity is electrically deposited on the charging device. Then, the polarity of the residual toner having opposite polarity is changed to the regular polarity by contacting with the charging device. Changing a polarity of the residual toner is effectively performed at a contact portion between the charging device and the toner removing structure. The residual toner changed to the regular polarity is then removed at the contact portion, so that the residual toner is returned to the image carrier. Meanwhile, the residual toner not removed is conveyed to a charging area of the charging device, and then is electrically discharged to the image carrier, by using the difference of electrical potential between the charging device and the image carrier.
Further, the image forming apparatus disclosed in Japanese Laid-open publication No. 2001-215799 includes a toner electrical potential controlling device, which slides in a direction of an image carrier axis, mounted on an upper area from a charging device in a direction of movement of the image carrier.
Also, in the image forming apparatus disclosed in Japanese Laid-open publication No. 10-213945, a different linear velocity is utilized between an image carrier and a charging device.

Image forming apparatus controlling polarity of residual toner and process cartridge for use in the same


A radiation detecting cassette has a casing including a first flat plate for facing a patient and a second flat panel for facing a surgical table. The first flat plate and the second flat panel are spaced from each other by a predetermined distance. The casing also includes a pair of first and second tapered side members disposed on respective side edges of the first and second flat plates. The first and second tapered side members are progressively tapered toward their distal ends. The first and second tapered side members house therein respective radiation shields, which in turn house therein a battery, a cassette controller, and a transceiver.

1. Field of the Invention
The present invention relates to a cassette storing therein a radiation conversion panel for detecting a radiation that has passed through a subject and converting the detected radiation into radiation image information.
2. Description of the Related Art
In the medical field, there have widely been used radiation image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel, which captures a radiation image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiation image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiation image in a phosphor and reproducing the radiation image as stimulated light by applying stimulating light to the phosphor.
The radiation film with the recorded radiation image is supplied to a developing device to develop the radiation, or the stimulable phosphor panel is supplied to a reading device to read the radiation image as a visible image.
In the operating room or the like, it is necessary to read and display a recorded radiation image immediately from a radiation conversion panel after the radiation image is captured for the purpose of quickly and appropriately treating the patient. As a radiation conversion panel which meets such a requirement, there has been developed a radiation detector having a solid-state detector for converting a radiation directly into an electric signal or converting a radiation into visible light with a scintillator and then converting the visible light into an electric signal to read a detected radiation image.
As disclosed in Japanese Laid-Open Patent Publication No. 2003-172783, for example, a radiation conversion panel, a wireless communication mechanism, and a battery are housed in a cassette, and the radiation conversion panel is irradiated with X-rays radiated from a radiation source that is disposed in confronting relation to the image capturing surface of the radiation conversion panel.
The cassette is disposed between a bed and a patient lying on the bed, and placed in a position facing the affected region of the patient for capturing a radiation image of the affected region. Generally, since the cassette is in the form of a thin box and needs to be inserted between the patient and the bed, the cassette that is put in position is physically burdensome to the patient, and cannot easily be placed between the patient and the bed. Accordingly, there have been demands in the art for cassettes that can easily and efficiently be placed in position between the patient and the bed.


The present invention provides a cleaning device (1) for cleaning the air-ionizing part (4) of an electrode (3), said device comprising a cleaning member (5) arranged to be in physical contact with the said air-ionizing part of said electrode, the air-ionizing part of electrode and the cleaning member being arranged to slide relative to each other. The cleaning device further comprises an actuator (6, 8, 9) arranged to activate the relative motion between said air-ionizing part (4) of the electrode (3) and the cleaning member (5). There is also provided an ionization electrode comprising an air-ionizing part and the cleaning device, as well as a ultrafine particle sensor, an air ionizer or an electrostatic air cleaner comprising such an electrode.

Air ionization electrodes are used in equipments such as photocopiers, electrical air cleaners, air ionizers and ultrafine particle sensors. They are frequently embodied as thin-wire electrodes or needle-tip electrodes and are connected to a high voltage (HV) supply, which is set at a voltage (Vcor) that is sufficiently high to ionize the air in the direct vicinity of the ionization electrode. In case a positive HV is used, the ionization electrode effectively emits airborne positive ions. Negative ions are emitted when a negative HV is used. The emitted ions can attach themselves to airborne particles, thereby charging the particles. In air cleaners, particle charging is useful to increase the particle capturing efficiency in charged media filters positioned downstream from the particle charging section. Concerning air ionizers, emitted ions (often present as a bipolar mixture) serve to prevent the build-up of static charges on surfaces through charge neutralization. In ultrafine particle (UFP) sensors, emitted ions serve to charge particles in the airflow passing through the sensor. The UFP sensor subsequently determines the airborne particle concentration by measuring the particle-bound charge (see e.g. J. Marra; Journal of Nanoparticle Research (2010), Vol. 12, pp. 21-37).
An important requirement for an ionization electrode is that the total emitted ionization current remains constant in time. This is usually fulfilled by introducing an electronic feedback mechanism, which ensures that the voltage applied to the ionization electrode is always such that a constant pre-set ionization current is emitted.
A further important requirement for an ionization electrode is that the spatial ion emission density around the electrode exhibits cylindrical symmetry (in which case the wire or needle being the axis of a cylinder) and remains substantially unchanged in the course of time. This is especially important for UFP sensors to ensure a uniform and predictable degree of particle charging at all locations within their particle charging section. However, due to the gradual (non-uniform) deposition of contaminants from air on the ionization electrode, this requirement is not always guaranteed. The deposits or contaminants on the electrode may consist of deposited particulate species, but also of NH4NOx and SiO2 residues. A build-up of NH4NOx results from the oxidation of N2 into NOx within the corona plasma region around the ionization electrode and the subsequent reaction of NOx with NH3 gas in the presence of moisture to form the solid NH4NOx (x=2 or 3) salt. SiO2 is formed as a leftover from the oxidation of silicone-containing gases in the corona plasma region. These deposits are insulating in nature and their formation and growth on an ionization electrode is experienced to gradually change the spatial characteristics of the emitted ion density around the electrode. In case needle-tip electrodes are used, the plasma region wherein air ionization occurs is mostly confined to the electrode tip. Contaminating deposits are therefore predominantly found at or in direct proximity to the electrode tip. In case thin-wire electrodes are used, air ionization and thus also the formation of contaminating deposits occurs across the entire length of the wire. In UFP sensors the presence of such deposits/contaminants affect the particle charging behavior in the course of time, thereby reducing the reliability of these devices. This is a problem since such sensors rely on the correct interpretation of measured current signals into key characteristics of the UFP pollution, notably the UFP number concentration N and the average particle size dp,av. Eventually, small amounts of the deposit may be released back into air as nanoparticles under the influence of the local corona current, thereby further affecting the reliability of the readings of UFP sensors. This problem is quite serious when UFP measurements are carried out in indoor environments, which are always to some extent polluted with silicone-containing gases.
To deal with this contamination problem, the ionization electrode(s) may be manually cleaned from time to time. Further, a few cleaning devices have been suggested, such as specific brushes disclosed in U.S. Pat. No. 5,768,087, but the scope of their applicability is severely limited. Moreover, cleaning may be costly and time consuming. The installation of an activated carbon filter upstream of the ionization electrode may adsorb silicone gases from sampled air but is not acceptable for UFP sensors because the presence of such a filter also affects the UFP concentration in the sampled air which one wants to measure. An activated carbon filter is not effective for avoiding the deposition of particulate contaminants or of NH4NOx onto the ionization electrode. Thus, there is a need in the art for improved or alternative cleaning devices for air-ionization electrodes such as needle-tip or thin-wire electrodes.

Cleaning device for cleaning the air-ionizing part of an electrode


Adaptive vision-based vehicle detection methods, taking into account the lighting context of the images are disclosed. The methods categorize the scenes according to their lighting conditions and switch between specialized classifiers for different scene contexts. Four categories of lighting conditions have been identified using a clustering algorithm in the space of image histograms: Daylight, Low Light, Night, and Saturation. Trained classifiers are used for both Daylight and Low Light categories, and a tail-light detector is used for the Night category. Improved detection performance by using the provided context-adaptive methods is demonstrated. A night time detector is also disclosed.

The present invention relates to vision systems for the detection of vehicles. More in particular it relates to vision systems for vehicle detection that can adapt to changing visibility conditions.
Vision systems are widely used for driver assistance and safety applications. Vehicle detection can be one of the critical functionalities of camera systems used for driver assistance. A drawback of existing vision systems is that the performance of vehicle detection drops as the visibility condition deteriorates. Vision systems may work well under good visibility, but can not adapt well to deteriorating visibility and thus may not perform well under such conditions.
Accordingly a context adaptive approach to alleviate visibility limitations and improve detection performance in low visibility conditions is required.

Context adaptive approach in vehicle detection under various visibility conditions


The present invention relates to a protocol-independent routing of data packets between a mobile station of a packet radio network and a party(Host) connected to an external network. In the invention, a data packet of an extraneous protocol(IPX) is transferred through a packet radio network using a second protocol as encapsulated in a data packet according to the second protocol. The transferring packet radio network does not thus need to understand the protocol of the transferred extraneous data packet or to be able to interpret the content of the data packet. A data packet network is connected to other packet radio networks, data networks or the backbone network between packet data networks via a gateway node(GPRS GSN), which uses the network-internal protocol towards the dedicated packet network and the protocol of each network towards other networks. When a data packet is transferred via a gateway node from a network into another network, the data packet is encapsulated in a packet according to the protocol of the new network. When the encapsulated data packet arrives in a node which supports the protocol of the encapsulated data packet, the encapsulation is stripped away and the data packet is routed forward according to the protocol of the data packet.

Mobile communication systems have been developed because there has been a need to allow people to move away from fixed telephone terminals without losing their ability to be reached. While the use of different data transmission services in offices has increased, different data services have also been introduced into mobile communication systems. Portable computers enable efficient data processing whereever a user moves. Mobile communication networks, provide a user with efficient access network to actual data networks for mobile data transmission. In order to do this, different new data services are designed for existing and future mobile communication networks. Digital mobile communication systems, such as the pan-European mobile communication system GSM (Global System for Mobile Communication), support particularly well mobile data transmission. General Packet Radio Service (GPRS) is a new service in the GSM system, and it is one the items of the standardization work of the GSM phase 2+ in ETSI (European Telecommunication Standard Institute). The GPRS operational environment consists of one or more sub-network service areas, which are interconnected by a GPRS backbone network. A sub-network comprises a number of packet data service nodes, which are referred to as GPRS support nodes (or agents) in this context, each packet data service node being connected to a GSM mobile communication network so that it is capable of providing packet data service for mobile data terminal equipment via several base stations, i.e. cells. The intermediate mobile communication network provides circuit switched or packet switched data transmission between a support node and mobile data terminal equipment. Different sub-networks are connected to an external data network, such as a public switched packet data network (PSPDN). The GPRS service thus produces packet data transmission between mobile data terminal equipment and external data networks with a, a GSM network acting as an access network. The GPRS service network operates almost independently of the GSM network. One of the requirements of the GPRS service is that it must operate with external PSPDNs of different types, for instance, with Internet or X.25 networks. In other words, the GPRS service and a GSM network should be capable of serving all users, irrespective of which type of data networks they want to register in via the GSM network. This means that the GSM network and the GPRS service have to support and handle different network addressing and data packet formats. This handling of data packets also comprises routing in a packet radio network. In addition, users should be able to roam from a GPRS home network into an extraneous GPRS network, the backbone network of the operator of which may support a different protocol (for instance, CLNP) than the home network (for instance, X.25).

Packet radio system and methods for a protocol-independent routing of a data packet in packet radio networks


This invention is directed to a cassette for electrophoresis gels comprising: first and second planar wall members having inner and outer surfaces, top and bottom edges, and lateral edges wherein the wall members are oriented generally parallel to each other and such that the inner wall of each wall member is proximate to the inner wall of the other wall member; spacing means disposed between the inner walls of the wall members and adapted to provide a space for an electrophoresis gel between the inner walls of the wall members, wherein the cassette has an interior which is defined by the space between the wall members; and locking means adapted to prevent locking engagement of the members unless the inner surfaces of the wall members and are substantially parallel to each other and are separated by a predetermined distance, and when the wall members are in locked engagement, to substantially prevent any movement of the wall members away from such locked engagement.

The present invention relates to a cassette for use in the formation of an electrophoretic gel. More particularly, the invention relates to such cassettes made of two parts and having locking means for holding the two parts together in a desired orientation. The subject invention also relates to a method for separating analytes, such as bio-organic molecules by the use of the above-mentioned cassettes.
Electrophoresis is the resolution of a complex mixture of macromolecules on the basis of charge and/or size under the influence of an electric field. Usually, separation of the charged molecules is based on the strength of the electrical field and the net charge, size and shape of the molecules. The separation can also, at least in part, be affected by other parameters, such as isoelectric points, ionic strength, viscosity and temperature of the medium in which the charged molecules are moving. As proteins and other biological molecules, such as DNA, RNA, enzymes, carbohydrates and the like are charged, electrophoresis techniques are ideal to separate them for analytical or preparative purposes.
It is common practice to use a cassette for conducting gel electrophoresis. The cassette comprises two flat plates, usually transparent glass or plastic, separated by spacing means and sealed along the sides and bottom edges to provide a void or confined space between the plates for placement of a suitable separation gel medium or electrophoresis gel such as agarose or a polyacrylamide in liquid form and its subsequent gelling or polymerization. The bottom of the cassette may be sealed with tape, another spacer, or by compression against a gasket. Once sealed on the edges and bottom, a solution of acrylamide, polymerization catalysts and buffers are introduced into the cassette and allowed to polymerize. After the gel has formed, the seal on the bottom, if used, is removed to provide an electrical contact for electrophoresis.
Automating this casting procedure is a means of reducing cost, user labor, and improving reproducibility. When a separation is run on the gel in the cassette, the top portion of the gel is in contact with a buffered solution and the lower portion of the gel is in contact with a second buffered solution. An electric current is applied to the buffered solution(s) or the gel, causing the migration and separation of the samples. By convention, the samples, for example, negatively charged proteins and nucleic acids, tend to run from the cathode (the top of the cassette, where the sample is placed) to the anode of the gel.
For the purposes of describing this invention, reference to the top or upper end of a cassette means the end of the cassette at which the wells are formed and in the instance of negatively charged samples, the cathode end of the gel. Additionally, the use of the terms "gelled" and "gel" refers to a solid state of the electrophoretic medium whether it be due to the cooling of an agarose gel or the polymerization of an acrylamide or acrylamide derivative.
In protein or nucleic acid fragment analysis, it is desirable to run more than one sample in a gel and to keep the samples separate. This is accomplished by sample separating means which is most commonly provided by the formation of wells at the sample-loading end of the gel (ie near the upper end of the cassette). Sample wells are formed usually by means of a removable piece or "comb" with teeth having the desired shape of the wells and having straight (level) substantially perpendicular ends to the teeth. The comb is brought into contact with the liquid separation medium before it gels or polymerizes and is positioned so that the teeth extend into the liquid medium while it gels. After the gel has set, the comb is removed to leave wells where samples can be positioned.
To improve the separation of certain types of molecules, it is common practice to change the composition of the gel medium in the direction of the electrophoresis. This change in composition can, for example, take the form of a discontinuity formed by a stacking gel at the upper most portion of the gel and a resolving gel at the lower most portion of the gel. Another example of a change in composition is the commonly used gradient gel consisting of a continuous gradient or a discreet gradient of bands each of uniform but different composition or any combination of continuous and discreet gradient. In order to provide accurate sample resolution, it is necessary that the desired electrophoresis composition remain undisturbed until the gel medium has gelled or polymerized completely, particularly in the instance of stacking and/or gradient gels.
Additionally, the uniformity of the gel is important to the quality of the separation obtained, for example, uniformity in the porosity of the gel or regions of the gel, uniformity (level and perpendicular to the plates) in the edge of the gel which first contacts the samples, uniformity in the thickness of the gel and uniformity (level and perpendicular to the plates) in the interface between discreet bands of gels (for example, between gradient gels or between stacking and resolving gels). Thus, it is desirable that the liquid gel-forming medium introduced into the cassette be disturbed as little as possible while gelling.
Casting polyacrylamide gels for vertical electrophoresis is commonly done by creating a cassette formed of two glass or plastic parallel sheets. Typically, the parallel sheets are held in position by a pair of spacers located at the vertical edges of the sheets. These spacers typically perform the functions of connecting the parallel sheets and keeping the faces of the sheets apart, creating a cavity for receiving the electrophoretic gel. The spacers also serve to maintain the sheets in substantially parallel orientation. The connection between the parallel sheets is sometimes effected by the use of corresponding ridges and recesses which form a friction-fit or snap-fit. This means of connecting the parallel sheets has been found to be inadequate. For instance, the connection may not be entirely even along the lengths of the spacers and small gaps may exist at points between the corresponding ridges and recesses. These gaps can cause slight variations in the distance between the parallel sheets. The gaps can also cause leakage of the gel to occur. Another problem with this means of connecting the parallel sheets is that there is nothing to prevent the sheets from undergoing some movement relative to one another. For instance, if the cassette is inadvertently knocked or bumped (perhaps during transportation), the connection between the sheets may be loosened and they may separate slightly from one another. In this case, the space between sheets may not be entirely uniform throughout.
In order to inhibit leakage and to enhance the connection between the sheets, the spacers of one wall member are sometimes glued or welded to the other wall member. However, the use of glue or welding is still not sufficient to ensure that the faces of the parallel sheets are in fact completely parallel over their entire areas. This is often because the spacers may not correctly engage the opposite wall member at all points along the spacers. For instance, small gaps may still exist at some points. Similarly, the use of glue or welding may cause slight inconsistencies resulting in non-uniform engagement between the spacers and the opposite wall members. When the opposed wall members are not completely parallel, the electrophoretic gel will not be of uniform thickness. The nearer the gel can be to having uniform thickness throughout, the better and more reliable will be the results of the electrophoretic procedure.
Accordingly, the present invention is directed towards a cassette for holding an electrophoretic gel having improved uniformity of thickness of the gel.

Cassette assembly for electrophoresis gels