Abstract: Provided herein are systems and methods of encoding messages into images. At least one server can identify a first image having a first plurality of pixels in a color space having a set of channels. The at least one server can generate, using a message to encode in the first image, a data matrix identifying a plurality of values. The at least one server can apply a machine learning (ML) model comprising a plurality of convolutional layers to the first image and to the data matrix to generate a second image having a second plurality of pixels in the color space. The second image can correspond to the first image encoded with the data matrix across the set of channels in the color space.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: Systems and methods are provided for efficient handling of user requests to access shared resources in a distributed system, which handling may include throttling access to resources on a per-resource basis. A distributed load-balancing system can be logically represented as a hierarchical token bucket cache, where a global cache contains token buckets corresponding to individual resources whose tokens can be dispensed to service hosts each maintaining a local cache with token buckets that limit the servicing of requests to access those resources. Local and global caches can be implemented with a variant of a lazy token bucket algorithm to enable limiting the amount of communication required to manage cache state. High granularity of resource management can thus enable increased throttle limits on user accounts without risking overutilization of individual resources.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: A breath analyte capture device includes a breath input port into which a user exhales a breath sample, and a cartridge insertion port for receiving a disposable cartridge containing an interactant. During exhalation of a breath sample, at least a portion of the breath sample is routed through the cartridge such that the analyte (such as breath acetone) is captured by the interactant. In some embodiments, the concentration of the analyte in the breath sample is measured by monitoring a chemical reaction that occurs in the disposable cartridge. The chemical reaction may be monitored by illuminating the cartridge at each of multiple light wavelengths while measuring reflected light.

Abstract: A user device and a breath analysis device (or other types of portable devices) use a pairing and communication protocol that address user convenience and connectivity issues. For example, a breath analysis device is associated with a unique identifier and the unique identifier is associated with an account corresponding to the user. Likewise, a user device is associated with a user device identifier and the user device identifier is associated with the account corresponding to the user. The breath analysis device and the user device can use at least one of the identifiers to determine whether the user device is authorized to pair with the breath analysis device, and vice-versa. If authorized, the breath analysis device and user device can pair with one another. Once paired, the user device may wirelessly communicate with the breath analysis device for various purposes, such as to retrieve and display breath analysis test results.

Abstract: A portable system is provided for measuring a ketone, such as an acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding ketone measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user. The application tracks, and generates graphs of, the ketone measurements, and may include various features for facilitating the analysis of the measurements.

Abstract: A system is provided for sensing an analyte in breath of a user. The system comprises a base; a breath input operatively coupled to the base that receives the breath; a cartridge coupled to the base and in fluid communication with the breath input to receive the breath, wherein the cartridge comprises an interactant subsystem that is selected to undergo a reaction with the analyte when the analyte is present in the breath and to undergo an optical change corresponding to the reaction; and an optical subsystem coupled to the base and configured to sense the optical change, wherein the optical subsystem generates an output comprising information about the analyte in response to the optical detection.

Abstract: A wearable breath analysis device is disclosed that may be worn, for example, around the neck or wrist of a user. The wearable device may be a stand-along device (in which case it may include a display that provides a user interface), or may operate in conjunction with a smartphone or other command device. The wearable device may include auditory and/or vibratory notice and communications features or capabilities, for example, such as a reminder or notice to conduct a breath analyte measurement, instructions to the user in the course of conducting the measurement, and notice of the breath analyte measurement results. The auditory or vibratory notice may be provided at the wearable, and/or at the command device where a command device is used. Related methods also are provided.

Abstract: A user device and a breath analysis device (or other types of portable devices) use a pairing and communication protocol that address user convenience and connectivity issues. For example, a breath analysis device is associated with a unique identifier and the unique identifier is associated with an account corresponding to the user. Likewise, a user device is associated with a user device identifier and the user device identifier is associated with the account corresponding to the user. The breath analysis device and the user device can use at least one of the identifiers to determine whether the user device is authorized to pair with the breath analysis device, and vice-versa. If authorized, the breath analysis device and user device can pair with one another. Once paired, the user device may wirelessly communicate with the breath analysis device for various purposes, such as to retrieve and display breath analysis test results.

Abstract: A system is disclosed that uses profiles of users, including monitored ketone levels of the users, to assess effectiveness levels of health programs (such as weight loss programs) assigned to the users, and to select health program modifications for the users. The system may use a machine learning (artificial intelligence) algorithm to adaptively learn how to classify users and to select messaging and behavioral modifications for the users. For example, in some embodiments the system classifies the users and provides associated health program recommendations using a computer model trained with expert-classified user data records. As another example, a set of rules may be used to generate the health program recommendations and related messaging, and the set of rules may automatically be modified over time based on feedback data reflective of health program effectiveness levels produced by such rules.

Abstract: A user device and a breath analysis device (or other types of portable devices) use a pairing and communication protocol that address user convenience and connectivity issues. For example, a breath analysis device is associated with a unique identifier and the unique identifier is associated with an account corresponding to the user. Likewise, a user device is associated with a user device identifier and the user device identifier is associated with the account corresponding to the user. The breath analysis device and the user device can use at least one of the identifiers to determine whether the user device is authorized to pair with the breath analysis device, and vice-versa. If authorized, the breath analysis device and user device can pair with one another. Once paired, the user device may wirelessly communicate with the breath analysis device for various purposes, such as to retrieve and display breath analysis test results.

Abstract: A portable system is provided for measuring a ketone, such as an acetone, in the breath or other bodily fluid of a user. The system includes a portable measurement device that analyzes fluid samples and generates corresponding ketone measurements. The portable measurement device communicates with an application which runs on a smartphone or other mobile device of the user. The application tracks, and generates graphs of, the ketone measurements, and may include various features for facilitating the analysis of the measurements.

Abstract: A wearable breath analysis device is disclosed that may be worn, for example, around the neck or wrist of a user. The wearable device may be a stand-along device (in which case it may include a display that provides a user interface), or may operate in conjunction with a smartphone or other command device. The wearable device may include auditory and/or vibratory notice and communications features or capabilities, for example, such as a reminder or notice to conduct a breath analyte measurement, instructions to the user in the course of conducting the measurement, and notice of the breath analyte measurement results. The auditory or vibratory notice may be provided at the wearable, and/or at the command device where a command device is used. Related methods also are provided.