Abstract: A system that performs wall detection and localization to determine a position of a device relative to acoustically reflective surfaces. The device emits an audible sound including a frequency modulated signal and captures reflections of the audible sound. The frequency modulated signal enables the device to determine an amplitude of the reflections at different time-of-arrivals, which corresponds to a direction of the reflection. The device then performs beamforming to generate a 2D intensity map that represents an intensity of the reflections at each spatial location around the device. The device detects wall(s) in proximity to the device by identifying peak intensities represented in the 2D intensity map. In some examples, instead of performing beamforming, the device can perform directional wall detection by physically rotating the device and emitting the audible sound in multiple directions. The device may perform ultrasonic wall detection using ultrasonic sound frequencies.

Abstract: Techniques for presence-detection devices to vary presence-detection sensitivity to detect different types of movements by objects, such as major movements and minor movements, using ultrasonic signals. The devices detect movement of a person in an environment by emitting ultrasonic signals into the environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person relative to the presence-detection devices. The presence-detection devices may control the presence-detection sensitivity in order to detect major movements, such as a user walking in a room, as well as objects minor movements, such as a user typing at a computer. By adjusting the presence-detection sensitivity, the devices are able to improve the overall accuracy of detecting the presence of users in an environment.

Abstract: Techniques for monitoring devices to use ultrasonic signals to detect and track the locations of moving objects in an environment. To determine distance information, the monitoring devices emit a frequency-modulated continuous wave (FMCW) signal at an ultrasound frequency range. Reflections of the FMCW ultrasonic signal are used to generate time-of-arrival (TOA) profiles that indicate distances between the monitoring device and objects in the environment. The reflections can be processed to suppress undesirable interferences, such as reflections off non-mobile objects in the environment (e.g., walls, furniture, etc.), vibrations off the floorings or the ceilings, etc. After processing the reflections, a heatmap can be used to plot the intensity of the reflections for the different TOAs of the reflections, and depict the movement of the user over time. Finally, a Kalman filter is used to smooth the peaks in the intensity values on the plot, and determine the trajectory of the human.

Abstract: Electrochemical water treatment devices are disclosed. The device includes an electrochemical separation module fluidly connectable to the source of water to be treated. The electrochemical separation module includes a first electrode, a second electrode, and a plurality of dilution compartments. Each of the dilution compartments includes a first region of ion exchange media having a first average particle size, a second region of ion exchange media having a second average particle size, and a third region of ion exchange media having a third average particle size. A volume of the second region of ion exchange media being greater than or equal to a total volume of the first and third regions of ion exchange media. Methods of facilitating treatment of water containing weakly ionized species, e.g., dissolved boron containing species and dissolved silica containing species, are disclosed. Electrochemical separation modules are also disclosed.

Abstract: Embodiments provide a filter with a generally rectangular, non-cylindrical profile. The filter may have multiple pleat packs positioned between pleat covers that define regions and flow channels in a cavity of the filter body. The pleat covers have openings that allow a fluid to flow through the multiple pleat packs via parallel flows or series flows. End caps bonded to the body define flow passages for directing the fluid from an inlet to an outlet via the pleat packs for series or parallel filtration. The pleat packs may be made of the same or different materials and may be configured with the same or different heights based on flow requirements. A cage or a separator may be positioned between the pleat packs. The pleat packs may be made of a continuous pleated membrane with bridges defining a space between the pleat packs to accommodate the cage or separator.

Abstract: Water filtration systems are disclosed. The water filtration systems include a regenerative media filter vessel comprising a housing, an inlet, and an outlet, a diffuser fluidly connected to the inlet and disposed within the regenerative media filter vessel, and at least one pump configured to direct water through the water filtration system. The housing of the regenerative media filter vessel comprises a concave lower portion centered about a vertical axis of the vessel. The position of the diffuser along a height of the regenerative media filter vessel is determined by at least a ratio of the height to an inner diameter of the regenerative media filter vessel and a radius of curvature of the concave lower portion. A regenerative media filter including a diffuser having asymmetrically spaced apertures is also disclosed.

Abstract: Embodiments provide a filter with a generally rectangular, non-cylindrical profile. The filter may have multiple pleat packs positioned between pleat covers that define regions and flow channels in a cavity of the filter body. The pleat covers have openings that allow a fluid to flow through the multiple pleat packs via parallel flows or series flows. End caps bonded to the body define flow passages for directing the fluid from an inlet to an outlet via the pleat packs for series or parallel filtration. The pleat packs may be made of the same or different materials and may be configured with the same or different heights based on flow requirements. A cage or a separator may be positioned between the pleat packs. The pleat packs may be made of a continuous pleated membrane with bridges defining a space between the pleat packs to accommodate the cage or separator.

Abstract: Techniques for presence-detection devices to emission levels of ultrasonic signals that are used to detect movement in an environment. The presence-detection devices may detect movement of a person by emitting the ultrasonic signals into an environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person relative to the presence-detection devices. However, presence-detection devices that continuously emit ultrasonic signals may experience reduced battery life, increased likelihood of overheating, etc. To reduce these negative effects, the presence-detection devices may reduce the emission levels of ultrasonic signals. For instance, once motion is detected, the presence-detection devices may, for a period of time, stop emitting ultrasonic signals or reduce the power level at which the ultrasonic signals are emitted.

Abstract: Techniques for presence-detection devices to detect movement of a person in an environment by emitting ultrasonic signals using a loudspeaker that is concurrently outputting audible sound. To detect movement by the person, the devices characterize the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. However, when a loudspeaker plays audible sound while emitting the ultrasonic signal, audio signals generated by microphones of the devices include distortions caused by the loudspeaker. These distortions can be interpreted by the presence-detection devices as indicating movement of a person when there is no movement, or as indicating lack of movement when a user is moving. The techniques include processing audio signals to remove distortions to more accurately identify changes in the frequency of the reflections of the ultrasonic signals caused by the movement of the person.

Abstract: Techniques for calibrating presence-detection devices to account for various factors that can affect the presence-detection devices' ability to detect movement. Presence-detection devices may detect movement of a person in an environment by emitting ultrasonic signals into the environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. However, factors such as environmental acoustic conditions, noise sources, etc., may affect the ability of the presence-detection devices to detect movement. To calibrate for these factors, the presence-detection devices may use a loudspeaker to emit an ultrasonic sweep signal that spans different frequencies in an ultrasonic frequency range.

Abstract: This disclosure describes presence-detection devices that detect movement of a person by emitting ultrasonic signals into an environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. The techniques include downsampling the audio signals from the carrier frequency range down to a frequency range with a center frequency around 0 Hz. A filter is applied to attenuate signals around 0 Hz and below (or above), such as the emitted signals. In addition to removing the emitted signals, the negative side (or positive side) of the audio signals are removed, but the Doppler shift is still represented in the remaining portion of the audio signals. By removing a portion of the audio signals, the amount of processing required to detect the Doppler shift in the reflections of the ultrasonic signals is reduced.

Abstract: A settling basin of a wastewater treatment system includes a collector chain including chain links having a plurality of side bars, stepped connecting pins configured to join the plurality of side bars and including a first end including a head portion having a cross-sectional area larger than portions of the plurality of side bars through which the stepped connecting pin extends, end caps configured to receive second ends of the stepped connecting pins, and apertures defined in the end caps and second ends of the stepped connecting pins configured to receive a retaining element that holds the end caps in position on the second ends of the stepped connecting pins.

Abstract: A system configured to improve echo cancellation for nonlinear systems. The system generate reference audio data by isolating portions of microphone audio data that correspond to playback audio data. For example, the system may determine a correlation between the playback audio data and the microphone audio data in individual time-frequency bands in a frequency domain. In some examples, the system may substitute microphone audio data associated with output audio for the playback audio data. The system may generate the reference audio data based on portions of the microphone audio data that have a strong correlation with the playback audio data. The system may generate the reference audio data by selecting these portions of the microphone audio data or by performing beamforming. This results in precise time alignment between the reference audio data and the microphone audio data, improving performance of the echo cancellation.

Abstract: A settling basin of a wastewater treatment system includes a collector chain including chain links having a plurality of side bars, stepped connecting pins configured to join the plurality of side bars and including a first end including a head portion having a cross-sectional area larger than portions of the plurality of side bars through which the stepped connecting pin extends, end caps configured to receive second ends of the stepped connecting pins, and apertures defined in the end caps and second ends of the stepped connecting pins configured to receive a retaining element that holds the end caps in position on the second ends of the stepped connecting pins.

Abstract: This disclosure describes presence-detection devices that detect movement of a person in an environment by emitting ultrasonic signals into the environment, and characterizing the change in the frequency, or the Doppler shift, of the reflections of the ultrasonic signals off the person caused by the movement of the person. In addition to detecting movement, and thus presence of a person, the presence-detection devices may include a microphone array to perform techniques for identifying a direction of movement of the person, and also to perform techniques for identifying a number of people that are in the room. Additionally, the techniques described herein include processing audio signals in such a way to allow for the use of on-board loudspeakers to transmit ultrasonic signals at out-of-band frequencies.

Abstract: A method is provided for detecting an interception of a communications session established by a user over a network, comprising the steps of: (i) monitoring communications sessions by the user over a profile time period to capture information identifying distinct communications to one or more identified network addresses and their timing over the profile time period; (ii) monitoring communications sessions within the profile time period to capture information characterising the content of transactions initiated in respect of said one or more network addresses; (iii) using the captured information to generate a profile characterising communications sessions established in respect of said one or more network addresses over the profile time period; and (iv) monitoring communications sessions with said one or more network addresses within a configurable detection time period to determine one or more measures of deviation from the profile generated at step (iii) thereby to detect the presence of an interception oc