Techniques are described for automatic interval metadata determination for intermittent time series data. In one example, a method for determining intermittent time series interval metadata includes detecting one or more time variables in a time series data set. The method further includes determining whether the one or more time variables are intermittently regular. The method further includes determining one or more respective time intervals for the one or more time variables. The method further includes determining the parameters of intermittency for the one or more time variables. The method further includes generating an output comprising information about the one or more time variables based on the one or more respective time intervals and the parameters of intermittency for the time variable.

Embodiments of the present disclosure provide a method and an apparatus for determining a similar document set to a target document from a plurality of documents. Each of the multiple documents and the target document may include a plurality of words, and each of words corresponds to a different integer. The method comprises: for each document among the plurality of documents and the target document, obtaining a set of integers associated with a document based on a set of words associated with the document, converting the set of integers associated with the document into a vector with a same dimension based on a predefined conversion rule; and determining the similar document set based on differences between the corresponding vectors for the multiple documents and the vector for the target document.

Methods and apparatuses are provided for detecting parameter. The method includes: acquiring at least one intake air quality parameter of an air intake area of an air purifier and at least one output air quality parameter of an air discharging area of the air purifier; determining a purification parameter corresponding to the intake air quality parameter of the air intake area and the output air quality parameter of the air discharging area; and outputting the purification parameter.

A ductless fume hood suitable for the removal of various chemical materials including toxic and non-toxic gases, vapors, particles, dust and unpleasant odors from a fluid stream. The ductless fume hood uses electronic devices and software to enable real time monitoring of gas levels in parts per million.

A vehicle and a method of controlling a dynamometer mode operation of a vehicle that includes requesting the dynamometer mode; monitoring for at least one non-dynamometer vehicle operating condition; if at least one of the non-dynamometer vehicle operating conditions is detected, prohibiting dynamometer mode; and if none of the non-dynamometer vehicle operating conditions is detected, operating the vehicle in dynamometer mode.

A TFT and manufacturing method thereof, an array substrate and manufacturing method thereof, an X-ray detector and a display device are disclosed. The manufacturing method includes: forming a gate-insulating-layer thin film (3'), a semiconductor-layer thin film (4') and a passivation-shielding-layer thin film (5') successively; forming a pattern (5') that includes a passivation shielding layer through one patterning process, so that a portion, sheltered by the passivation shielding layer, of the semiconductor-layer thin film forms a pattern of an active layer (4a'); and performing an ion doping process to a portion, not sheltered by the passivation shielding layer, of the semiconductor-layer thin film to form a pattern comprising a source electrode (4c') and a drain electrode (4b'). The source electrode (4c') and the drain electrode (4b') are disposed on two sides of the active layer (4a') respectively and in a same layer as the active layer (4a'). The manufacturing method can reduce the number of patterning processes and improve the performance of the thin film transistor in the array substrate.

A method is provided for making smooth crystalline semiconductor thin-films and hole and electron transport films for solar cells and other electronic devices. Such semiconductor films have an average roughness of 3.4 nm thus allowing for effective deposition of additional semiconductor film layers such as perovskites for tandem solar cell structures which require extremely smooth surfaces for high quality device fabrication.

An improved cemetery experience whereby the cemetery and accompanying facilities may celebrate and demonstrate the passion and hobbies of the deceased individual. The contemplated themed cemetery may be a stand-alone cemetery that celebrates a common passion of a plurality of individuals, yet still maintains the traditional burial and memorialization process. The themed cemetery may take a specific event, or commonly understood and loved location and memorialize that location in the theme of a cemetery where those with that common interest and enjoyment of the commonly understood location may desire to be buried. The cemetery would closely resemble both visually, and physically a replica of the theme being celebrated and may provide space for the deceased while still providing adequate income and revenue in the way of advertising for the operator.

An arrangement is disclosed for a meter cabinet, distribution cabinet or empty housing, including a frame and a door, wherein the frame can carry a door and the door is attached pivotally to the frame on its hinge side. The door may be aligned in relation to its frame quickly and without problems, with an adjustment device for aligning the door in the closed condition, the adjustment device being associated with the frame.

A detector with a telescopic carrier/guide rod at which a measuring probe is disposed at one end, wherein the carrier/guide rod features at least two tubes longitudinally movable inside one another, in which respectively two tubes disposed adjacently in radial direction form an outer tube and an inner tube, whereby the respective outer tube at its overlapping tube end facing the measuring probe features a clamping means for engaging the inner tube. In accordance with this invention, the clamping means is formed as a clamping device that features a profile clamp with a quick-locking device. The profile clamp comprises a holding ring with two half shell-shaped clamping ring segments that are interconnected flexibly on one side and on the opposite side they can be clamped together with a clamping lever. The holding ring features ring breakthroughs and the outer tube the corresponding tube breakthroughs for the accommodation of clamping pieces that are pressed against the inner tube when clamping the clamping ring segments together under pressure. Preferably a clamping ring segment is formed on the holding ring.

A gas generator and process for converting a fuel into an oxygen-depleted gas and/or hydrogen-enriched gas. The gas generator is preferably used for generating protection gas or reducing gas for start up, shut down or emergency shut down of a SOFC or SOEC. The process for converting fuel into oxygen-depleted gas and/or a hydrogen-enriched gas includes combusting the fuel in a primary catalytic burner with an oxygen-containing gas to produce a flue gas with oxygen, combusting or partially oxidizing the flue gas comprising oxygen with excess fuel in a secondary catalytic burner to produce a gas with hydrogen and carbon monoxide, and reducing the trace amounts of oxygen from the gas comprising traces of oxygen and obtaining an oxygen-depleted gas, or reducing the carbon monoxide present in the gas by conversion to carbon dioxide or methane to obtain a hydrogen-enriched gas.

Polishing pads for polishing semiconductor substrates using eddy current end-point detection are described. Methods of fabricating polishing pads for polishing semiconductor substrates using eddy current end-point detection are also described.

A Continuous Transmission Frequency Modulated (CTFM) detection apparatus is provided. The apparatus includes a projector, a sensor, and a hardware processor. The projector is configured to transmit a frequency modulated transmission wave at a given transmission period. The sensor is configured to receive a reflected wave, the reflected wave comprising a reflection of the transmission wave on a target object. The hardware processor is programmed to at least generate a beat signal based at least in part on the transmission wave and the reflected wave, extract asynchronously from the transmission period a processing signal from the beat signal, and generate information related to the target object based on the processing signal.

The present invention relates to a system for determining a distance, a transponder, a position detection apparatus, and a method therefor. The method for determining a distance comprises providing a position detection apparatus (101), and a transponder (105). The method further comprises generating (201) a pseudo number sequence, transmitting (202) the pseudo number sequence, receiving (203) the pseudo number sequence; modulate (204) the received pseudo number sequence by means of delaying the recieved pseudo number sequence a predetermined number of clock cycles from a group of at least two predetermined number of clock cycles. The method further comprises transmitting (205) the modulated pseudo number sequence, recieving (206) the modulated pseudo number sequence, detecting (207) a path time of the pseudo number sequence, by means of delaying and correlating the generated pseudo number sequence with the received modulated pseudo number sequence, wherein the delay time corresponds to the path time, The method further comprises detecting (208) a clock correction factor for the transponder (105) using the received modulated pseudo number sequence, calculating (209) a flight time of the pseudo number sequence between the position detection apparatus and the transponder by means of the path time, the clock correction factor, and the predetermined number of clock cycles of the transponder, and calculating (210) the distance between said position detection apparatus and said transponder by means of the flight time.

Methods and systems for detection of an occupancy status of a space monitored by a system (100) are described herein. The method comprises detecting a magnetic field value at the space by a magnetic field sensor (210) of a sensing device (104). The detected magnetic field value with a reference magnetic field value, to determine a magnetic occupancy status (MOS) of the space. The MOS is indicative of the change in the occupancy status of the space. The change in the occupancy status is indicative of one of a change from empty to occupied occupancy status, and a change from occupied to empty occupancy status. Further, when the MOS indicates the change in the occupancy status of the space, a radar sensor (212) of the sensing device (104) is activated to determine a radar occupancy status (ROS) by generating at least one radar reading from the radar sensor (212). The ROS is indicative of the change in the occupancy status of the space. Thereafter, the change in the occupancy status of the space is established when the ROS indicating the change in the occupancy status of the space is in agreement with the MOS. Further, the established change of the occupancy status in the space is communicated to a central unit (102) of the system (100).

A dual mode electromagnetic detection system and a protective dome for the electromagnetic detection system are described. The protective dome includes a substrate having a portion transparent to both infrared radiation and radio frequency radiation. The portion of the substrate includes a macromolecular material including a polymer selected from a family of polyolefins and an antistatic additive.

There is provided a method for positioning of user equipment. The method for positioning of user equipment, includes: receiving, by the user equipment, a signal from an external antenna, the signal being radiated in a cyclic pattern; measuring, by the user equipment, strength of the received signal, characterizing, by the user equipment, the measured strength to form a signal pattern over a time period; and determining a position of the user equipment based on the signal pattern.

A method is disclosed for determining the position of an RFID transponder. Separate signals of at least two electromagnetic alternating fields are emitted from at least two antenna to one RFID transponder. The antenna are spaced at a distance from each other so that the two electromagnetic alternating fields are emitted at a distance from one another. The emitted electromagnetic alternating fields to the one RFID transponder are reflected so that the reflected electromagnetic alternating fields are sent back to the antenna. The transit times of the electromagnetic alternating fields are determined from emission to receiving back at the antenna. The distances between the antenna and the RFID transponder are determined, and the position of the RFID transponder from the at least two distances is determined relative to the at least two antenna.

A testing device for FMCW radar includes an input for receiving a chirp signal generated by the radar. An IQ down-converter coupled to the input down-converts the chirp signal. A digitizer extracts digitized IQ signals from the down-converted chirp signal. A processor coupled to the digitizer determines at least one of frequency linearity and phase noise of the chirp signal.

In one embodiment, a radio altimeter tracking filter is provided. The filter comprises: a wireless radio interface; a processor coupled to the wireless radio interface; a memory coupled to the wireless radio interface; wherein the wireless radio interface is configured to wirelessly receive a radio altimeter signal and convert the radio altimeter signal to a baseband frequency signal, wherein the a radio altimeter signal sweeps across a first frequency spectrum between a first frequency and a second frequency; wherein the processor is configured to pass the baseband frequency signal through a filter executed by the processor, the filter comprising a passband having a first bandwidth, and wherein the filter outputs a plurality of spectral chirps in response to the baseband frequency signal passing through the first bandwidth; wherein the processor is configured to process the plurality of spectral chirps to output characteristic parameters that characterize the radio altimeter signal.

A blind spot detection system for a motorcycle, which includes an accelerometer, a gyroscope, and a detection device for detecting the presence of a vehicle in at least one blind spot. The accelerometer detects a gravity force vector, and the gyroscope detects the position of the motorcycle relative to the gravity force vector such that a lean angle of the motorcycle is calculated. The detection device is then configured to maintain the same position of the motorcycle relative to the gravity force vector and compensate for the position of the motorcycle if the lean angle is greater or less than 90°, such that the detection device is able to detect the presence of the vehicle in the at least one blind spot, independent of the lean angle of the motorcycle.

The invention relates to determining the presence of flowing water (B) in the vicinity of a vehicle. It relies on a pair of sensors (6a) emitting periodic signals, receiving reflected signals and comparing them to each other to determine the presence of flowing water in the area surrounding the vehicle. Another approach relies on a single sensor and analyses perturbations in the signal of said sensor. Preferably, the invention uses sensors already installed, namely parking sensors and a radar.

A radar apparatus detects an observation point distance and an observation point azimuth. In addition, the radar apparatus calculates an observation point lateral position and an observation point vertical position based on the observation point distance and the observation point azimuth. Furthermore, the radar apparatus determines that a traveling vehicle is detected when a number of observation points included within a side determination range is equal to or greater than a predetermined traveling vehicle determination count, based on the observation point lateral position and the observation point vertical position. The side determination range is set so as to include a passing determination line so as to extend in a direction at 90 degrees relative to a front-rear direction of the vehicle to the side of the vehicle.

A fill level measurement device for determining a topology of a filling material surface in a container including an antenna apparatus, a receiver and control circuitry. An emission angle of the antenna apparatus and a spatial position of the antenna apparatus relative to the filling material surface is settable by the control circuitry. A resultant emission direction of the fill level measurement device is changeable by the control circuitry by controlling a position of the antenna apparatus and by controlling an emission and/or receiving angle of the antenna apparatus.

The present disclosure relates to a method and apparatus for detecting a target object by a radar device for a vehicle. The method includes recognizing the situation that causes the deterioration in the function of a radar, and preventing the performance from deterioration through a signal processing technology. The apparatus includes: a signal transmitting unit that transmits a transmission signal for detecting a target object; a signal receiving unit that receives a reception signal generated by a reflection of the transmission signal; a signal analyzing unit that calculates frequency spectrum information of the reception signal, and extracts periodicity information for determining a periodicity of the frequency spectrum information; a determining unit that determines whether a clutter structure exists; and a target detecting unit that detects a target object by deleting a peak value component of the periodicity information when it is determined that the clutter structure exists.

In an embodiment of the disclosed technology, a visual output of data from a ground-penetrating radar and magnetic field measuring device is displayed on a visual medium. The display has a first exhibition of output from the ground-penetrating radar device and a second from a magnetic field measuring device, such as a very low frequency (VLF) receiver. Using an identical axis, such as an X-axis measuring time or distance, output of each device is exhibited and overlaid over one another. In this manner, one can detect (using two different methodologies and uses) the visual exhibition of both to best determine the location of a metal or electrical target.

Disclosed is a system for determining a protection level. The system includes a receiver configured to receive an error augmentation for a satellite orbit and clock error, an error augmentation for an ionospheric error, an error augmentation for noise and multi-path between a receiver and a satellite, and an error augmentation for a tropospheric error, a first calculator configured to calculate a first adjustment coefficient to be applied to the error augmentation for the satellite orbit and clock error and the error augmentation for the ionospheric error, and a second calculator configured to calculate a protection level by applying the first adjustment coefficient.

The present invention provides an improved, quantitative, standardized method of hydrating succulent plants by a plant owner. The method includes calculating the amount of water and watering frequency required, depending on environmental conditions, such as substrate used to grow a plant, relative humidity and temperature, and using a demarcated container for watering the plant, all of which maintains and prolongs the health, vitality, beauty and longevity of the succulent plant.

An adjustable water retention device for a plant pot has a plant container nesting in a second outer pot, with a facilitated flow of water communicating between the second outer pot and the plant container, wherein the second outer pot rests on a base.

Some embodiments provide irrigation valve control apparatuses comprising: a solenoid configured to cooperate with a plunger; an input stimulus source coupled with the solenoid and configured to apply an input stimulus while a plunger drive signal is not being applied and that is sufficiently small to not cause the plunger to move; sampling circuitry configured to measure one or more voltage measurements corresponding to one or more voltages across the solenoid, wherein the one or more voltage measurements are dependent upon the current position of the plunger relative to the solenoid; and control circuitry cooperated with the sampling circuitry to receive the one or more voltage measurements from the sampling circuitry, wherein the control circuitry is configured to determine whether the plunger is in one of the open and closed positions based on the one or more voltage measurements.

A valve is used to meter a fluid. The valve can be fashioned in particular as a fuel injection valve for internal combustion engines. The valve has a housing part that is surrounded on its outer side by an extrusion coating. On the outer side of the housing part there is fashioned at least one recess into which the extrusion coating is at least partly introduced.

An angle measuring device or system can include a wrench and a digital angle meter. The wrench can include a head for engaging a fastening device, a central axis about which the wrench or bracket rotates during use, and a longitudinal axis perpendicular to the central axis. The digital angle meter can be attached to the wrench or bracket and include a housing, a processor, and at least one gyrometer. The at least one gyrometer including a first axis extending parallel to the longitudinal axis for determining the rotational orientation of the wrench or bracket relative to a reference position. A sensor of the digital angle meter allows for an automated and accurate calculation of a total angle of rotation of the nut or bolt about the central axis using a ratcheting wrench.

A multi-contact type position detection apparatus for a target board includes a first membrane board having a plurality of first signal lines formed in a first direction, a second membrane board having a plurality of second signal lines formed in a second direction, and a plurality of dots which are formed on the first membrane board or the second membrane board such that the first membrane plate and the second membrane plate are spaced at a predetermined distance from each other, wherein the plurality of dots can be arranged at a distance of “k/2±A (A is 1%˜2% of k)” when a magnetic body diameter of a pin attached on the target board is “kmm”.

An electronic apparatus and a method for detecting status of keys thereof are provided. The electronic apparatus comprises a key module, a key control circuit, a conversion circuit with calibration mechanism and a processor. The key control circuit detects whether any of keys in the key module is pressed. If the detection result is affirmative, the press status of each of the keys is scanned by the key control circuit to obtain a coarse scan result. The conversion circuit with calibration mechanism is configured to perform the other system function of the electronic apparatus. When the processor determines that at least one of the keys is not pressed according the coarse scan result, the conversion circuit with calibration mechanism is switched to assist a re-scan operation of the press status of the at least one of the keys.

Modifying a digital data stream that includes immediately consecutive code words of different length by segmenting, based on a certain block grid, the digital data stream. Each block of the block grid includes a fixed number of bits. It is determined whether all bits of the last block associated with the digital data stream are occupied by data of the digital data stream. If not all bits of the last block are occupied, the unoccupied bits of the last block are padded with bits of an end-of-record (EOR) indicator. If all bits of the last block are occupied, attaching an EOR indicator to the digital data stream is skipped.

A displacement sensor having a rectangular shaped elastic member. A piezoelectric element is attached to a first main face of the elastic member. The piezoelectric element has a rectangular-shaped piezoelectric sheet and electrodes on both main faces of the piezoelectric sheet. The piezoelectric sheet is made of poly-L-lactic acid and is at least uniaxially-stretched. The piezoelectric element is attached so that the uniaxial-stretching direction of the piezoelectric sheet is 45° relative to a long-side direction of the elastic member. When the elastic member is bent along the long-side direction, the piezoelectric sheet is stretched along the long-side direction, and the piezoelectric element generates voltage of predetermined level.

Embodiments of the present invention relate to detecting irregularities in audio, such as music. An input signal corresponding to an audio stream is received. The input signal is transformed from a time domain into a frequency domain to generate a plurality of frames that each comprises frequency information for a portion of the input signal. An irregular event in a portion of the input signal corresponding to a set of frames in the plurality of frames is identified based on a comparison of frequency information of the set of frames to the frequency information of other sets of frames of the plurality of frames. This allows an indication of the irregular event to be provided, or for the input signal to be automatically synchronized to a multimedia event.

An apparatus for filling joints in precast concrete structures includes a core that has exceptionally low creep and conforms to ASTM D 1752 made of controlled particle size composites of recycled cellular rubber and plastic materials in the form of a rectangular slab. Holes are drilled through a central area and countersink recesses are formed around the holes. An outer coating of a thermoplastic polyurethane/polyurea elastomer system of a thickness of 0.075 inch covers the slab and countersink recesses. The coated core is abrasion and UV resistant while having the creep characteristics needed to make a dam expansion joint filler.

The utility model discloses a monolithic reinforced concrete piece for the construction of buildings which is characterized for having six columns arrange in a hexagonal distribution, a continuous beam with variable depth supported by the columns making six spans and forming a hexagonal perimeter viewed from top, a corbel fixed along the beam's external face, and a roof which has a hexagonal shape with a circular hole in the center in plan view and cambered in the elevation view which rest on the continuous beam. In use the reinforced concrete hexahedral module can be cast-in-place or pre-cast and transported to its final position on the construction site and used as part of a building defining the space and ambience of said building. This invention has the advantage of being safe, strong and reliable, providing a fast new method of construction for different kinds of buildings.

The present invention provides in one aspect for a bracket for use with insulated forms for concrete walls. The bracket has an attachment plate for overlying the exterior of the insulated form to provide for a means of attaching the header or rim joist to the bracket. The bracket is provided an anchoring plate extending from the attaching plate for insertion into the interior of the insulated form. The present invention also provides for a method of attaching a header or rim joist to a concrete wall formed using insulated forms. The method involves cutting a vertical slot in the insulated form and inserting a bracket into the slot. The bracket has an attachment plate for overlying the exterior surface of the insulated form and an anchoring plate extending from the attachment plate through the slot into the interior of the insulated form. Concrete is poured into the form and allowed to set, after which the header or rim joist is attached to the brackets.

The present disclosure relates to a dose indicator comprising, a chassis comprising a 42 chassis frame and a displacement portion, an indexable first display unit, mountable on the chassis, the first display unit being indexable about a first display axis, the indexable first display unit comprising a plurality of indexing teeth, a first display non-return arm, and a drive pawl connected at its proximal part to the displacement portion, the drive pawl comprising a socket at its distal part, the socket being adapted to engage an indexing tooth of the first display unit during indexing. The disclosure further relates to an actuator for an inhaler, wherein the actuator comprises a dose indicator as described above. The present disclosure is also directed to an inhaler comprising such actuator.

An oral-nasal cannula receives exhaled gases from the nose and mouth of a patient. The exhaled gases are transported to variable flow valves that can variably restrict the flow of the gases through the valves upon software generated signals. The exhaled gases pass through the variable flow valves and mix so that they can be measured by a single sensor such as a sensor of a capnometer. Based upon information gathered by the capnometer, the variable valves can be adjusted in real-time according to a software method in order to identify a variable valve flow configuration that maximizes the amount of CO2 received and measured by the capnometer. In this manner, the software can adapt a single capnometer to measure exhaled gases regardless of whether a patient breathes primarily through their nose or mouth or some proportion of the two.

Provided are systems, methods, and electronic vapor devices configured to provide spirometer functionality and respiratory medication dispensing which can couple and function symbiotically with a portable electronic communication device.

A system for determining an optimal hardness of a patient interface device includes a fit score determination unit structured to receive a 3-D model of the patient interface device and a 3-D model of a patient's face and to determine a fit score between the patient interface device and the patient's face based on the 3-D model of the patient interface device and the 3-D model of the patient's face, and a hardness determination unit structured to determine a hardness value of the patient interface device based on the determined fit score.

Systems, methods, and devices are disclosed for humidifying a breathing gas that reduces and/or eliminates the dangers and discomforts experienced by a patient. In one aspect, a system for humidifying gases includes a body, extending along a first axis from a first face to a second face, a first lumen at the first face, through which fluid enters the body, a second lumen at the first face through which fluid exits the body and a nonporous membrane located inside the body and extending from the first face to the second face wherein gas moving through the nonporous membrane is humidified by the fluid.

Embodiments described herein generally relate to phased array antenna systems or packages and techniques of making and using the systems and packages. A phased array antenna package may include a distributed phased array antenna comprising (1) a plurality of antenna sub-arrays, which may each include a plurality of antennas, (2) a plurality of Radio Frequency Dies (RFDs), each of the RFDs located proximate and electrically coupled by a trace of a plurality of traces to a corresponding antenna sub-array of the plurality of antenna sub-arrays, and (3) wherein each trace of the plurality of traces configured to electrically couple an antenna of the plurality of antennas to the RFD located proximate the antenna, wherein each trace of the plurality of traces is configured to transmit millimeter wave (mm-wave) radio signals, and wherein the plurality of traces are each of a substantially uniform length.

In embodiments of the present invention improved capabilities are described for an antenna-based detection method and system for sensing an environmental change condition. The method and system is adapted such that the states comprising the environmental change condition are capable of being determined at the location of the detection point utilizing only the magnitude component of the antenna impedance as altered by the discrete change in the environmental condition.

A tracking antenna system for discrete radio frequency spectrums includes a reflector, a pedestal supporting the reflector, a radome assembly enclosing both, a first feed for gathering radio waves within a first of discrete RF spectrums that is removably disposed in front of the reflector at the focal point, a first RF module operably connected to the first feed for converting the first gathered radio waves to first electronic signals, a feed mount for removably supporting the first feed and configured to removably support a second feed for gathering radio waves within a second of discrete RF spectrums, and a module mount for removably supporting the first RF module and configured to removably support a second RF module for converting the second radio waves to second electronic signals. A method of using the tracking antenna system adaptable for discrete radio frequency spectrums is also disclosed.

A single molecule sensing or detecting device includes a first electrode and a second electrode separated from the first electrode by a gap. The first electrode and the second electrode have an opening formed therethrough. At least one of the first electrode and the second electrode is functionalized with a recognition molecule. The recognition molecule has an effective length L1 and is configured to selectively bind to a target molecule having an effective length L2. The size of the gap is configured to be greater than L2, but less than or equal to the sum of L1 and L2.

A sputtering system that includes a sputtering chamber having a target material serving as a cathode, and an anode and a work piece. A direct current (DC) power supply supplies electrical power to the anode and the cathode sufficient to generate a plasma within the sputtering chamber. A detection module detects the occurrence of an arc in the sputtering chamber by monitoring an electrical characteristic of the plasma. In one embodiment the electrical characteristic monitored is the impedance of the plasma. In another embodiment the electrical characteristic is the conductance of the plasma.