Abstract: Provided is a security monitoring method including outputting a multi-tone sound wave configured with a linear sum of sine waves having a plurality of frequency components inside a security monitoring space, receiving the multi-tone sound wave and calculating a sound field, calculating and storing sound field information according to frequency through the sound field, comparing reference sound field information according to frequency with the currently measured sound field information and determining whether a sound field variation occurs, and analyzing whether the sound field variation occurs collected for a certain predetermined period and distinguishing at least two events among intrusion, motion and temperature variation situations on the basis of correlation between the reference sound field spectrum and consecutive sound field spectra.

Abstract: Provided is a security surveillance system and method capable of separately detecting fire and intrusion situations on the basis of a sound field variation, including a sound generating device outputting, into a set security surveillance space, a multi-tone sound wave formed of a linear sum of sine waves having a plurality of frequency components, a sound receiving device obtaining sound field information for each frequency represented as sound pressure and a phase from a sound wave received in the security surveillance space, and a sound field signal processing device storing sound field information for each frequency obtained from the sound receiving device in a preparation mode, comparing the stored sound field information with current sound field information for each frequency output from the sound receiving device in a surveillance mode, and determining occurrence of a security situation.

Abstract: A gas monitoring apparatus according to the inventive concept includes a sound generator, a sound receiver, and a sound field signal processor. The sound generator continuously outputs a sound signal into a gas monitoring space. The sound receiver receives a sound signal reflected from the gas monitoring space. The sound field signal processor obtains sound field information on the received sound signal, calculates a sound field spectrum for the sound field information, uses a correlation between the calculated sound field spectrum and a reference sound field spectrum, and determines whether there are gas leak and mixing in the gas monitoring space, wherein the reference sound field spectrum is a sound field spectrum according to frequency measured in a case where a gas is not leaked in the gas monitoring space, and the sound signal is formed by a linear sum of sine waves that have a plurality of frequency components.

Abstract: Disclosed are a method for measuring a acoustic transfer function of a predetermined space to be secured or monitored through a correlation between sound signals acquired from a sound source generating device and a sound measuring device and a method and a system for judging whether there is an intrusion object by using a difference between an initially set acoustic transfer function information and varied acoustic transfer function information by using the method for measuring the transfer function. In the present disclosure, when an object moves or an intrusion object is generated in a predetermined space, intrusion or no intrusion is monitored by variation of the acoustic transfer function varied by the intrusion object even though there is no noise generated by the intrusion object.

Abstract: A method of manufacturing a piezoelectric speaker comprises forming a piezoelectric thin film and then forming an upper electrode and a lower electrode on and beneath the piezoelectric thin film, respectively, forming a damping material layer for attachment of the piezoelectric thin film below the piezoelectric thin film with the upper and lower electrodes formed thereon and therebeneath, attaching the piezoelectric thin film to an acoustic diaphragm in an inclined structure in which the piezoelectric thin film is horizontally turned from the acoustic diaphragm, and performing drying at room temperature; and fixing the acoustic diaphragm to a frame using an adhesive material with high elasticity.

Abstract: The present disclosure relates to security system and method based on sound field variation pattern. The present disclosure identifies a slow variation pattern of a acoustic transfer function occurring due to a gradual change in temperature and humidity of air according to a change in time and a change in a characteristic of an acoustic element, from a sudden sound field variation pattern within an internal space occurring due to an intrusion from an outside, activation of an air conditioning and heating device, and the like, or within a surveillance space induced by a change in an acoustic physical property. The present disclosure identifies sound field variation patterns occurring due to a change in an acoustic structure by an intrusion and a change in temperature and convection by air conditioning and heating. The present disclosure stores and verifies image information using an image obtaining apparatus.

Abstract: A method of operating an electronic device when a disaster occurs and disaster information is received. The disaster information may be relayed by an external electronic device, a server, or could be detected by one or more sensors within the electronic device that detect a possible emergency such as the user has fallen, or there has been impact sensed consistent with an accident, etc. The method includes receiving disaster information, determining whether a rescue request will be made by analyzing the disaster information, and transmitting rescue request information based on the determination result. An electronic device is configured to perform the method.

Abstract: Provided is a security monitoring method including outputting a multi-tone sound wave configured with a linear sum of sine waves having a plurality of frequency components inside a security monitoring space, receiving the multi-tone sound wave and calculating a sound field, calculating and storing sound field information according to frequency through the sound field, comparing reference sound field information according to frequency with the currently measured sound field information and determining whether a sound field variation occurs, and analyzing whether the sound field variation occurs collected for a certain predetermined period and distinguishing at least two events among intrusion, motion and temperature variation situations on the basis of correlation between the reference sound field spectrum and consecutive sound field spectra.

Abstract: Disclosed is a security monitoring method determining whether a trespasser is detected and a position of the trespasser in a set security space and monitoring sound generated at the position of the trespasser by using an acoustic image generated from acoustic signals generated by an acoustic generating device and an acoustic measuring device in an array type. An exemplary embodiment of the present disclosure provides a security monitoring system including: an acoustic generating device that generates acoustic signals; a plurality of acoustic measuring devices that receive the acoustic signals; and an acoustic image processing device that generates an acoustic image using a beamforming algorithm from the acoustic signals received in the plurality of acoustic measuring devices and determines a position of a trespasser by comparing the acoustic image after the trespasser is detected with the acoustic image before the trespasser is detected.

Abstract: Disclosed are a method and a system for monitoring a fire based on a detection of sound field variation. The system for monitoring a fire based on a detection of sound field variation includes: a sound generator outputting a sound wave within a defined space according to input voltage; a sound receiver receiving the sound wave within the defined space and obtaining a sound pressure from the received sound wave; and a fire monitor using a sound transfer function representing a ratio of the sound pressure obtained by the sound receiver to input voltage of the sound generator in a preparation mode to calculate reference sound pressure information, using the sound transfer function in a monitoring mode to calculate current sound pressure information, and comparing the reference sound pressure information with the current sound pressure information to determine whether a fire occurs.

Abstract: Provided is a security surveillance system and method capable of separately detecting fire and intrusion situations on the basis of a sound field variation, including a sound generating device outputting, into a set security surveillance space, a multi-tone sound wave formed of a linear sum of sine waves having a plurality of frequency components, a sound receiving device obtaining sound field information for each frequency represented as sound pressure and a phase from a sound wave received in the security surveillance space, and a sound field signal processing device storing sound field information for each frequency obtained from the sound receiving device in a preparation mode, comparing the stored sound field information with current sound field information for each frequency output from the sound receiving device in a surveillance mode, and determining occurrence of a security situation.

Abstract: A security system and a method of determining whether there is an intrusion are provided. A correlation between sound signals obtained from a sound source generating device and a sound-field variation measuring device is used to measure a acoustic field in a certain space. A difference between an initially set acoustic field and a changed acoustic field is used to determine whether there is an intruding object in a certain space. The security system includes a sound source generating device for generating a sound source; and a sound-field variation measuring device for measuring a acoustic field formed by the sound source, wherein an initially set acoustic field is compared with the measured acoustic field to determine whether there is an intrusion.

Abstract: Provided are a micro-electromechanical systems (MEMS) microphone and a method of manufacturing the same. A manufacturing process is simplified compared to a conventional art using both upper and lower substrate processes. Since defects which may occur during manufacturing are reduced due to the simplified manufacturing process, the manufacturing throughput is improved, and since durability of the MEMS microphone is improved, system stability against the external environment is improved.

Abstract: A piezoelectric speaker and a method of manufacturing the same that can obtain a high sound pressure using a piezoelectric thin film are provided. The piezoelectric speaker includes a piezoelectric thin film, electrodes formed on an upper surface or upper and lower surfaces of the piezoelectric thin film, a damping material layer formed on the lower surface of the piezoelectric thin film, and a frame attached around at least one of the piezoelectric thin film and the damping material layer using an adhesive.

Abstract: A condenser microphone having a flexure hinge diaphragm and a method of manufacturing the same are provided. The method includes the steps of: forming a lower silicon layer and a first insulating layer; forming an upper silicon layer on the first insulating layer; forming sound holes by patterning the upper silicon layer; forming a second insulating layer and a conductive layer on the upper silicon layer; forming a passivation layer on the conductive layer; forming a sacrificial layer on the passivation layer; depositing a diaphragm on the sacrificial layer, and forming air holes passing through the diaphragm; forming electrode pads on the passivation layer and a region of the diaphragm; and etching the layers to form an air gap between the diaphragm and the upper silicon layer. Consequently, a manufacturing process may improve the sensitivity and reduce the size of the condenser microphone.

Abstract: The present disclosure relates to security system and method based on sound field variation pattern. The present disclosure identifies a slow variation pattern of a acoustic transfer function occurring due to a gradual change in temperature and humidity of air according to a change in time and a change in a characteristic of an acoustic element, from a sudden sound field variation pattern within an internal space occurring due to an intrusion from an outside, activation of an air conditioning and heating device, and the like, or within a surveillance space induced by a change in an acoustic physical property. The present disclosure identifies sound field variation patterns occurring due to a change in an acoustic structure by an intrusion and a change in temperature and convection by air conditioning and heating. The present disclosure stores and verifies image information using an image obtaining apparatus.

Abstract: Provided is an active piezoelectric energy harvester, which can control a direct current voltage applied to an embedded variable capacitance layer to precisely adjust a resonance frequency in real time, and thus achieve a simpler structure and a smaller size compared to a conventional one that adjusts the resonance frequency using a separate variable capacitor provided outside. Further, the active piezoelectric energy harvester can precisely adjust the resonance frequency even when the frequency of vibration varies over time as in a real natural vibration environment or when it is degraded to undergo a variation in its own resonance frequency, and thus can continuously maintain optimal energy conversion characteristics.

Abstract: A micromini condenser microphone having a flexure hinge-shaped upper diaphragm and a back plate, and a method of manufacturing the same are provided.

Abstract: In a piezoelectric speaker, an acoustic diaphragm is thicker than a piezoelectric thin film and is formed of a more flexible and higher elasticity material than the piezoelectric thin film, thereby greatly improving output sound pressure in a low frequency band and reducing sound distortion. Further, the piezoelectric thin film is attached to the acoustic diaphragm in an inclined structure in which the piezoelectric thin film is horizontally turned from the acoustic diaphragm, thereby preventing a standing wave from being created by structural symmetry and minimizing sound distortion.

Abstract: Provided are a piezoelectric energy harvester and a method of manufacturing the same. The piezoelectric energy harvester is configured to obtain primary voltage from a piezoelectric layer vibrated to generate voltage and secondary voltage from a magnetostrictive layer vibrated to induce a change in magnetic field and a coil surrounding the magnetostrictive layer. Thus, it is possible to obtain sufficient voltage to drive a power conditioning circuit (PCC).