Abstract: A method includes reconstructing measured projection data using an iterative statistical reconstruction algorithm that reduces image artifact caused by differences in variances in projections of the measured projection data used to update a voxel of the image for one or more voxels of the image. A reconstructor includes a processor that reconstructs measured projection data using an iterative statistical reconstruction algorithm that reduces or mitigates image artifact caused by differences in variances in projections used to update a voxel of the image for one or more voxels of the image. A computer readable storage medium encoded with computer executable instructions, which, when executed by a processor of a computer, cause the processor to: reduce image artifact caused by differences in variances in projections used to update a voxel of an image for one or more voxels of the image using an iterative statistical reconstruction algorithm.

Abstract: A system for confirming the detection of a fire using a plurality of radiation or flame sensors each equipped with a radiation detector and an optical filter having a spectral transmission characteristic in which at least one optical filter is redundant to at least one other optical filter. The result is a system having operationally redundant sensors. In use, if a fire is detected by one of the redundant sensors without including the other redundant radiation sensor in the fire detection calculation, then a fire detection algorithm can switch to the other operationally redundant sensor to check for confirmation of a fire. Due to the spatial separation and if the object is small and close, a different result will be obtained with the redundant detector being used in the calculation compared to the primary detector that is associated with the redundant detector.

Abstract: Systems and methods for indicating the unsafe service handling temperature of an information handling system component are disclosed. A method may include sensing a surface temperature of the component and comparing the surface temperature to a first and second threshold temperatures. The method may further include displaying various temperature warning by multiple temperature indicators if the surface temperature is above or below the threshold temperatures.

Abstract: Changes in equipment cooling performance may be detected by indirectly measuring cooling performance by way of a cooling efficiency indicator. An operating cooling efficiency indicator is calculated as a ratio between equipment electrical power consumption and a temperature differential between the equipment and an ambient temperature. The operating cooling efficiency indicator is compared to a baseline cooling efficiency indicator to detect changes in cooling performance.

Abstract: A fire detection system comprises a detection unit (2A) able to measure an electrical quantity between a first (BOA) and a second (B1A) terminal, and a first detector (11A) connected to the first and second terminals (BOA, B1A) and able to form a first value of the electrical quantity in a determined state of the first detector, for example in the event of the detecting of a fire in a first zone (Z). A second detector (12A) connected to the first and second terminals (BOA, B1A) is able to form a second value of the electrical quantity in said determined state, that is to say for example in the event of the detecting of a fire in a second zone, and a third value of the electrical quantity in another state different from the determined state, that is to say for example during normal operation. The first value and the third value are different from the second value.

Abstract: The invention relates to a flame-monitoring device in which an a.c. input voltage (U1) is limited to a voltage limit (U2) by means of a voltage limiter (4). Said voltage limit (U2) is applied to a flame sensing device (7) which operates by means of the rectifying effect of a flame, and through which a current (i) flows, especially when a flame (6) is present. An asymmetric voltage limit (U2) can be defined by said voltage limiter (4), said limit being then applied to the sensing device (7).

Abstract: A plurality of sensors are positioned in a home. Sensor fire data is delivered to a remote server, and the sensor fire data is segmented into single-state blocks broken up by door opening and closing events. The door opening and closing events represent potential state changes in the home where the number of people present in the home may have changed. The raw data from the sensor fires are then processed into adjacent sensor fires and used to populate adjacency matrices and frequency distributions. That information is subjected to a statistical goodness-of-fit test, which reveals a probability indicating the likelihood a given data block should be attributed with the single or multiple person state. The single versus multiple person state is passed along with these data to the remainder of the data analyses, which can then be properly aware of which data should be treated with due suspicion.

Abstract: A sensor of incident ambient photons is combined, in a detector with one or more sensors responsive to other types of ambient parameters such as gas, humidity, temperature or the like. Outputs from the sensors are processed to establish the existence of one of a hazardous condition, a non-hazardous condition and a false alarm.

Abstract: A robot apparatus which may be turned to a sound source direction by a spontaneous whole-body concerted operation. With the possible range of rotation of the neck unit of a robot apparatus 1 of ±Y° and with the relative angle of the direction of a sound source S to the front side of the robot apparatus 1 of X°, the entire body trunk unit of the robot apparatus 1 is rotated through (X?Y)°, using the leg units, while the neck joint yaw axis of the robot apparatus is rotated through Y° to the direction of the sound source S, so that the robot apparatus is turned to the direction of the sound source S.

Abstract: A refrigerator adapted for playing and recording voice messages is disclosed. The refrigerator includes a cabinet for enclosing a refrigerating compartment, the cabinet having a door for providing access to the refrigerating compartment, a message center operatively connected to the cabinet. The message center includes a speaker, a microphone, and a display.

Abstract: A method and a fire-alarm system controls stationary fire-extinguishing systems. The fire-alarm devices of the fire-alarm system are equipped with one or more detectors. If at least one pre-adjustable alarm threshold of a fire identification characteristic is reached, the fire-extinguishing device is activated and the fire detectors are selectively switched to a higher stage of sensitivity. The detectors to be switched are locally selected depending on the actual development of the fire in terms of space. The dynamic adaptation of the sensitivity of the detectors to the development of a fire permits analyzing the development of the fire through the generated smoke, water vapor or extinguishing-water mist, and to influence the fire-extinction process in a targeted manner.

Abstract: A fire alarm having an electronic evaluator, an optical module, a temperature sensor, and at least one combustion gas sensor, where the electronic evaluator diagnoses one of a plurality of fire types and selects an application-specific algorithm based on the diagnosed fire type. The electronic evaluator uses the signals from the sensors to diagnose at least one of a plurality of types of fire. The fire alarm may have at least one polarization filter which may be an active polarizer with electrically adjustable polarization plane.

Abstract: In a constant temperature liquid circulating apparatus, in order to determine parts and locations requiring maintenance work and maintenance time intervals before the occurrence of an irregular operation, so that any downtime in operation of a constant temperature liquid circulating apparatus is made as short as possible, a system is provided in which respective components of the apparatus are provided with sensors for use in monitoring various kinds of condition amounts in a continuous manner. Especially, among such components, a three-way proportional valve is provided between the outlet of a heat exchanger and an inlet to a holding tank, in a cooling liquid circulating circuit which supplies a constant temperature cooling liquid to a load, and a sensor is provided which detects a degree of valve opening of the three-way proportional valve.

Abstract: A repository including: an input unit (3) for setting the temperature of the interior (2) of a repository (1); a measuring unit (5,6) for measuring the temperature of the interior of the repository (1); a controller (4) for holding ID data to specify the repository itself and communicatively outputting the measurement data to the external; and an auxiliary power source (13) for communicating the measurement data to the external even during interruption of power supply. A central controller 11 for collecting the measured data from each repository and judging whether abnormality occurs or not is connected to plural repositories to fabricate a monitoring system. When abnormality is detected, the measured data as well as ID data and time data are transmitted to a user through the Internet.

Abstract: A method for monitoring the operating temperature within a card shelf having a plurality of discrete electronic cards includes receiving a first temperature indicative of an operating temperature of an item on one of the electronic cards. A second temperature indicative of an ambient temperature in which the electronic card is operating is also received. Based on the first and second temperatures, a temperature controller determines whether the item is operating within specified limits.

Abstract: A smoke detector verification system, which includes a smoke detector, a portable computer system and an optical receiver, verifies the operation of the smoke detector. The smoke detector includes a light emitting diode (LED) that is periodically modulated to provide status information about the smoke detector. The portable computer system stores the status information that is received from the optical receiver, which is coupled to the portable computer system. The optical receiver receives the status information from the LED and provides the received status information to the portable computer system.

Abstract: It is prevented that a malfunction occurs because of a noise. A smoke detection section samples as a smoke detection signal a signal digitized after being output from a light reception section when a light emission section glows, and updates a previous smoke detection signal. A noise detection section samples as a noise detection signal a signal output from the light reception section when the light emission section is not driven to glow. When the noise detection signal exceeds a predetermined noise level, a noise de-influence unit disables updating of the previous smoke detection signal with the newly sampled smoke detection signal so as to process a noise.

Abstract: A multi-unit ambient condition detecting system incorporates either a wired or a wireless communication medium wherein the units are in bi-directional communication with one another. Units can incorporate programmed processors and ambient condition sensors such as smoke or gas sensors. In response to detected local ambient conditions, the respective units can transmit messages indicative of the level of sensed ambient condition to other units in the system. The units can maintain running totals of levels of ambient conditions received from other units in the system and combine those received indicators, along with one or more locally generated indicators, to determine that a selected condition, such as fire or gas is present in at least a portion of the region being monitors. Output devices coupled to the communication medium can provide human discernable audible or visible indicators of the presence of one or more selected conditions.

Abstract: A method for generating an electrical signal and a sensor device (10) for executing the method. The signal is generated because of a change in a fluid-filled space. A sensor element (12) of the sensor device (10) detects the heat transfer over time between the sensor element (12) and the fluid. The sensor element (12), which has a temperature-dependent electrical conductivity and to which a voltage has been applied, is brought to a temperature which lies outside the range of the fluid temperatures. In the passive phase, the fluid is brought to a constant passive temperature by a heat transfer between the sensor element (12) and the surroundings. The sensor device (10) provides a constant passive output voltage. A heat transfer between the sensor element (12) and its surroundings takes place in the active phase by changes in the fluid-filled space. The sensor device (10) provides an active output voltage, which is different from the passive output voltage.

Abstract: A heat detector that includes a temperature sensing and testing circuit that provides an increased accuracy temperature sensing range and a push-to-test circuit that is electronically functional at low ambient temperatures. The heat detector includes a sensing circuit consisting of a voltage divider formed from a supply resistor and a thermistor. The thermistor is connected directly between a detector voltage input to a control unit and ground. The push-to-test circuit includes a parallel combination of a test resistor and a transistor each connected between the supply resistor and a voltage source. During normal operating conditions, base current is supplied to the transistor such that the transistor functions as a short circuit connection between the supply resistor and the voltage source. Upon depression of a push button, the base of the transistor is connected to the emitter such that the transistor acts as an open circuit.

Abstract: The device according to the invention provides a non-contacting temperature sensing device incorporating micro-bolometric detectors as the suitable infrared sensors for automotive applications. A first and second infrared sensors each include an active infrared sensing element and a temperature drift compensating element. A current bias is applied to the active infrared sensing element as well as to the temperature drift compensating element, which is identical in structure with the active infrared sensing element, and the voltage outputs of these two elements pass through a differential amplifier. The fluctuation in the substrate temperature or the ambient temperature affects the active sensing element and the compensating element in the same way, thus it is cancelled out. Instead of using one spectral band of the infrared radiation, as in the prior art, two spectral bands are used resulting in a first and second signal generated by the first and second infrared sensors.

Abstract: A device having an image-providing sensor, hereinafter designated as “image sensor,” operating in the visible and near-infrared range, an thermal image-providing sensor, hereinafter designated as “thermal-image sensor,” operating in the thermal radiation range and having a lower resolution than the image sensor, and an electronic evaluation system. The evaluation system determines whether one or both of the signals generated by the sensors are used for determining whether an alarm condition exists. As a result, the detectability of low-contrast objects is increased, the false alarm rate is reduced, and object classification is made possible.

Abstract: A temperature determining apparatus produces a predetermined reference voltage from an operating voltage supplied thereto from the outside, divides the reference voltage with a pair of resistance values having different temperature-resistance characteristics to produce a first divided voltage and divides the reference voltage with a pair of resistance values having the same temperature-resistance characteristic to produce a second divided voltage, and compares the first and second divided voltages to determine a threshold temperature. Since the reference voltage is constant as long as an ambient temperature is not changed even when the operating voltage is changed, the first and second divided voltages are not changed depending on the operating voltage, thereby allowing the determination of an ambient temperature with favorable accuracy in a wide range of operating voltages.

Abstract: A crop frost prediction system (20) is provided. The system (20) exposes a thermally radiant surface (22) to atmosphere (26) and senses the temperature of the thermally radiant surface (22). The sensed temperation, alone or in combination with other variables, is used by a processor (38) to calculate whether frost is likely to occur. The system (20) capitalizes on the understanding of the inventor that the thermally radiant surface (22) will dissipate heat (24), and thus have a lower temperature than the ambient air, under conditions of low humidity and clear night sky.

Abstract: A method of arming a security system comprising one or more send-only RF sensor. The method comprises the steps of receiving a request to arm the system from a keypad, determining if a faulted status exists in the receiver/controller, if a faulted status does exist, then changing the faulted status to a restored status, and arming the security system when there are no faulted statuses in the receiver/controller.

Abstract: A method for fluid pressure analytical electronic heat and fire detection, and a corresponding heat detector, used for detecting heat and fire, having no moving component, such as a valve, switch, membrane, diaphragm, or similar actuatable device of moving parts, for effecting activation of a warning or alarm signal indicating a condition of excessive heat or fire. The analytical electronic heat detection mechanism is based on electronic circuitry including at least one fluid pressure transducer, logic, and other cooperatively functioning electronic components, for highly accurately and reproducibly, first analyzing a potential condition, and then logically determining, an actual condition of excessive heat or fire. The electronic heat detection mechanism is fully functional, by having at least one fluid chamber closed to any external source of fluid pressure. The invention includes an automatic electronic testing procedure for naturally stimulating the heat detection mechanism for effecting operation.

Abstract: The present invention provides a highly sensitive, intelligent, reliable, and effective process and system for detecting fire, which may be used in any industrial or other environment. The process and system for flame detection in accordance with the present invention features wide infrared spectrum sensitivity, which facilitates increased sensitivity to any sign of a flame or fire. The process and system of the present invention utilizes digital processing and analysis of data, calibration of operation parameters from temperture data, an intelligent controller (microprocessor) for discriminating against false alarms, and an elaborate multi-stage alarm system, selectively triggered by the controller.

Abstract: Apparatus, for example postage metering apparatus is described as being provided with tamper detection means. The tamper detection means may comprise an electrically conductive or resistive first layer extending between a wall of a secure housing and components critical in the proper functioning of the apparatus. An indicator may include a second electrically conductive layer extending adjacent and electrically isolated from the first layer and means responsive to completion of an electrical path between the layers or means responsive to change in resistance of the resistive layer. In an alternative construction, the tamper detection means includes a sealed enclosed space containing gaseous substance at a pressure above ambient air pressure and means responsive to a decrease in the pressure in the space to permit a mechanical interposer to engage an operable mechanical element of the apparatus to inhibit operation thereof.

Abstract: A controlling interface unit is linked to a plurality of event sensors associated with a premises. There is at least one manner of establishing communication, using wired communication lines or radio transmissions between this interface unit and, on the one hand, a remote alarm receiving center for monitoring the sensors at the premises, and, on the other hand, a remote auxiliary facility for filtering out potential false alarms from those premises. The interface unit is capable of routing signals originating from a selected type of sensor to the auxiliary filtering facility instead of or in addition to transmitting the same signals to the alarm receiving center. Depending on the circumstances, feedback signals may then be transmitted from the auxiliary filtering facility to the controlling interface unit to negate an alarm condition. Optionally, a memory unit may be linked to the controlling interface unit to store data from the event sensors for a limited time period.

Abstract: A fire detector with a maximum average response time of less than 1.5 minutes is obtained by combining a smoke detector with a CO.sub.2 detector that uses NDIR sensor technology. The smoke detector is used to detect smoldering fires and to help prevent false alarms attributable to the CO.sub.2 detector. The CO.sub.2 detector is used to rapidly detect fires by measuring the rate of change of CO.sub.2 concentration. A signal processor generates an alarm signal when a smoldering fire is detected or alarm logic indicates that a fire has been detected.

Abstract: A fire detector having a greatly reduced frequency of generating false alarms. An AND gate is responsive to outputs from first and second fire detector modules that are responsive to the detection of first and second characteristics of a fire, respectively, to signal the detection of a fire if both of these characteristics have been detected. At least one override path is included to enable the occurrence of a particular type of fire to be signaled that would not otherwise be signaled by the output of said AND gate.

Abstract: A set of first and second detecting units detects an emergency. First and second pseudo-emergency generating units generate a pseudo-emergency for the first and second detecting units. A driving unit alternately drives the first and second pseudo-emergency generating units. An abnormality detecting unit detects operation of the first and second detecting units detecting the pseudo-emergency from the first and second pseudo-emergency generating units, the abnormality detecting units performing a predetermined indication when thus-detected operation is abnormal. An emergency detection outputting unit, in an emergency, outputs an emergency detection signal in response to reception of emergency detection signals from both the first and second detecting units.

Abstract: A multiple sensor smoke detector includes at least an ionization and a photoelectric sensor. Outputs from the sensors are fed to circuitry for generating continuously variable coefficients. One coefficient corresponds to each sensor output. Respective coefficients and sensor outputs are multiplied in multiplier circuitry to produce processed outputs. The processed outputs are combined in a summing circuit to produce at least one output value indicative of a level of detected smoke. The coefficient generating circuitry, the multiplier circuitry and the combining circuitry could be implemented in a programmed microprocessor. The coefficient generating circuitry could be implemented using prestored membership functions indicative of various types of fires.

Abstract: A fire detecting apparatus is designed to have improved reliability by reducing the possibility that the apparatus is influenced by an environmental change, external noise or the like which would otherwise cause erroneous fire information to be sent to a receiving unit to generate a false alarm.

Abstract: A fire alarm system includes a control unit which communicates with a plurality of spaced apart smoke detectors by a bi-directional communications link. The smoke detectors are separate from one another, and spaced apart, and are associated together in different, overlapping groups. Each group of detectors is physically arranged with the members of the group adjacent to one another in a relatively localized area. Signals from the detectors are transmitted to the control element for processing. The control element squares each of the signals for a given group, sums those signals and then takes a square root. The resultant processed value is associated with a selected one of the detectors of the group. Similar processing takes place for each of the groups. As a result of the processing, each of the detectors has associated therewith a processed smoke value which takes into account not only values received from the associated detector, but also values received from one or more adjacent detectors in a group.

Abstract: A fire detection system includes an elongated liquid filled tube with a fluid coupled alarm switch, with a flexible diaphragm which senses a change from the liquid to vapor phase in the presence of an overheat or fire condition to provide an alarm. To prevent false alarms due to normal expansion of the liquid under changing ambient temperature conditions, a compensator is provided which in one form is a pair of mechanically coupled bellow type containers, filled with the same liquid which will expand at the same rate as the fluid under normal ambient temperature conditions but in a fire condition will resist faster expansion thus causing the alarm switch to be actuated. In another embodiment, a bimetallic bellows is utilized to match the liquid expansion but resist greater vapor pressure. Yet in another embodiment the change in liquid flow rate due to a fire condition is sensed to prevent further accommodation to the normal increase in volume of the liquid.

Abstract: A fire detector having a greatly reduced frequency of generating false alarms. An AND gate is responsive to outputs from first and second fire detector modules that are responsive to the detection of first and second characteristics of a fire, respectively, to signal the detection of a fire if both of these characteristics have been detected. At least one override path is included to enable the occurrence of a particular type of fire to be signalled that would not otherwise be signalled by the output of said AND gate.

Abstract: An alarm for multistaged heat detection is provided. The alarm provides a multi-point detecting structure by applying a digital operation unit. The alarm has both pre-alarm and normal alarm modes. The digital operation unit coordinates the sound and light output to effect different alarm signals. A power capacity checking circuit is included to indicate a low operational state of the system power. A coercing alarm circuit is also included for stopping all detecting to cause the system to output an alarm signal in an emergency.

Abstract: A fire alarm system utilizes outputs from different types of fire sensors, such as photoelectric smoke sensors or ionization type smoke sensors and combines those outputs by subtraction so as to establish a delay interval during which one or both of the sensor output values must exceed a predetermined threshold value to cause the system to go into an alarm condition. Prior to subtracting the outputs from one another, each of the outputs can be raised to a predetermined exponential value so as to emphasize the effects of larger sensor output values. Where the two types of fire sensors each are generating outputs indicative of a fire condition, the calculated delays will be relatively short. In instances where only one of the two sensors is generating an output indicative of a fire condition, the calculated delay will be longer, so as to inhibit false alarms.

Abstract: A fire alarm system automatically adjusts sensitivity of individual sensors based on evaluation of background level over a period of time. High sensor signals which do not trigger a fire alarm may, after a delay time, result in decreased sensitivity to avoid false alarms. On the other hand, low peak values stored over a period on the order of months result in an automatic increase in sensitivity of the system. The sensitivity is adjusted by changing the delta threshold of an alarm threshold over a quiescent sensor signal average.

Abstract: A heat detector uses a single comparator operating in conjunction with a dynamically changing thermal reference that ensures quick response to rapid rates of thermal change and a fixed threshold that indicates an ambient temperature exceeds a threshold temperature. The inputs of the comparator receive different ones of the output signals of two thermal sensors. One thermal sensor responds nearly instantaneously to changes in ambient thermal conditions. The other thermal sensor is mounted on a printed circuit board operating as a heat sink and responds more slowly to changes in ambient thermal conditions. The difference between the thermal sensor output signals is zero at a lower ambient temperature when the rate of thermal change exceeds a preset amount and at a higher ambient temperature when the rate of thermal change is relatively slow.

Abstract: Rooms in a building each have a heating, ventilating and air conditioning system (HVAC), a room control unit having a temperature controller, and various sensors. The control unit monitors the presence of persons in the room, determines the season, sets back the temperature in an empty room by a variable amount which the HVAC can restore in a given time, and restores the temperature to the previous user request when the user returns but to a standard temperature if the user has newly checked in. An outside hallway panel briefly displays, when interrogated by a maid, a person's presence. By monitoring maid requests, door status and maid activity, the unit indicates on a room map whether the room is being cleaned, clean, or ready to rent. By establishing the heat loss/gain (l/g) factor of a room with the HVAC off and comparing it with the time to heat or cool the room, HVAC failures are determined. By comparing a room's l/g factor with those of its neighbors, room environment failures are determined.

Abstract: A heat detector includes an external temperature detector for detecting an external temperature outside the heat detector and an internal temperature detector for detecting an internal temperature inside the heat detector. A microcomputer calculates a temperature difference between the external temperature detected by the external temperature detector and the internal temperature detected by the internal temperature detector. The microcomputer monitors the above-described temperature difference to detect an event in which the temperature difference has remained greater than a predetermined value for a predetermined duration or longer. If the microcomputer detects that the temperature difference has remained greater than the predetermined value for the predetermined duration or longer, the microcomputer outputs an abnormal signal representing that the external temperature detector is abnormal.

Abstract: A broadband transformer with one-to-one turns ratio provides common mode noise suppression in a transmission line. One winding of the transformer is connected in series with each of the two wires of the transmission line. The transmission line is connected between a multiplexer device, coupled in turn to a plurality of spaced-apart fire detectors, and an output fire alarm control panel. Common mode noise on the transmission line results in only a very small noise current appearing at the central fire alarm panel. As a result, a noise rejection for the system is increased.

Abstract: Disclosed is a fire detection and engine monitoring system of the type which utilizes a pair of elongated thermistor strands extending over substantially the same path to provide redundancy. A resistance of the two thermistor strands are sensed and a resistance difference signal is generated. The resistance signal is monitored for abnormal differences between the two identical thermistor devices which are essentially exposed to the same operation conditions. Such differences are indicative of the deterioration over time of the condition of one of the sensors.

Abstract: An apparatus and a method for determining a failure of a temperature sensor for an automatic transmission of a motor vehicle are provided. A first temperature sensor senses the temperature of a coolant for cooling an engine. A second temperature sensor senses the temperature of a hydraulic oil in the transmission. The output of the second temperature sensor is compared with a first failure determination level and a second failure determination level. It is determined that the second temperature sensor is in a failure when the output of the second temperature sensor is lower than the first failure determination level or higher than the second failure determination level. The output of the first temperature sensor is compared with a first predetermined level and a second predetermined level which is higher than the first predetermined level.

Abstract: An abnormal temperature detector for an electronic apparatus includes a plurality of temperature detectors, an abnormality detector, and a power supply controller. The plurality of temperature detectors are arranged at least at one detection point of a rack, of an electronic apparatus, in which a plurality of wiring boards having IC elements mounted thereon are housed, and respectively output detection outputs when a temperature at the detection point becomes a preset temperature or more. The abnormality detector detects that detection outputs are output from all the temperature detectors at the detection point. The power supply controller interrupts a power supply of the apparatus in response to an abnormality detection output from the abnormality detector.

Abstract: To improve probability of detection in the early stages of fires, a fire alarm (1) with a temperature sensor (3) is proposed, having a structural member (12) that causes the sensor (3) to react only to temperature changes in the ambient air, and which change with a frequency of from 0.1 to 20 Hz. The fire alarm (1) becomes particularly insensitive to errors when there is a second fire sensor (7) that reacts to fire aerosol, there being a threshold value circuit (9) that lowers the threshold value for the fire aerosol sensor (7) when the temperature sensor (3) exceeds a preset threshold value.

Abstract: A fire detector having a first sensor for emitting a first output signal in response to a fire phenomenon, a second sensor for detecting a source of false alarm conditions generated by man and/or machinery and an evaluating circuit. The evaluating circuit has a mechanism for activating an alarm signal when the value of the output of the first sensor exceeds a threshold value. The threshold value is set by the second sensor in response to the detection of signals generated during normal use of the premises to be protected.

Abstract: In a fire monitoring system for monitoring the occurrence of a fire in which a space to be monitored is imaginarily subdivided into plural subspaces so that plural channels passing through the subspaces are set so as to intersect to each other in a lattice form. The propagation speed of ultrasonic waves propagating through each of the channels is measured, on the basis of which the propagation speed of the ultrasonic waves in each of the subspaces is calculated in the same manner as the solution for each element of a matrix is obtained, and then the temperature in each of the subspaces is obtained. By providing the system with a humidity sensor, the temperature for a dry condition is obtained.