Abstract: A robot is placed on a first surface of a panel. The robot includes a body and first and second feet connected to the body via joints. A flux conducting device is positioned on an opposing second surface of the panel, opposite the robot, so that each foot of the robot is magnetically coupled to the flux conducting device. The flux conducting device is moved along the exterior surface to pull the robot along the interior surface until an obstacle on the first surface is encountered. The robot decouples one of the feet from the flux conducting device, lifts the decoupled foot above the obstacle, and moves the decoupled foot past the obstacle.

Abstract: An apparatus and methods for adaptive and autonomous calibration of pulse transit time measurements to obtain arterial blood pressure using arterial pressure variation. The apparatus and methods give pulse transit time (PTT) devices an ability to self-calibrate. The methods apply a distributed model with lumped parameters, and may be implemented, for example, using pulse transit time measurements derived from a wearable photoplethysmograph (PPG) sensor architecture with an intervening pressurizing mechanism.

Abstract: A robot is placed on a first surface of a panel. The robot includes a body and first and second feet connected to the body via joints. A flux conducting device is positioned on an opposing second surface of the panel, opposite the robot, so that each foot of the robot is magnetically coupled to the flux conducting device. The flux conducting device is moved along the exterior surface to pull the robot along the interior surface until an obstacle on the first surface is encountered. The robot decouples one of the feet from the flux conducting device, lifts the decoupled foot above the obstacle, and moves the decoupled foot past the obstacle.

Abstract: An apparatus and methods for adaptive and autonomous calibration of pulse transit time measurements to obtain arterial blood pressure using arterial pressure variation. The apparatus and methods give pulse transit time (PTT) devices an ability to self-calibrate. The methods apply a distributed model with lumped parameters, and may be implemented, for example, using pulse transit time measurements derived from a wearable photoplethysmograph (PPG) sensor architecture with an intervening pressurizing mechanism.

Abstract: An apparatus and methods for performing a circulatory measurement on an extremity, such as a hand, of a subject. The circulatory measurement results in the derivation of an output circulatory metric that may encompass blood pressure or various other circulatory metrics. An indicator of an input circulatory metric at a locus on the extremity is measured, such as a pulse transit time, and calibrated to account for the hydrostatic component of blood pressure arising due to vertical displacement of the extremity with respect to the heart.

Abstract: Methods and a computer program product for using a circulatory measurement on an extremity of a particular subject to derive an aortic blood pressure for that subject. A model is constructed that maps a peripheral cardiovascular waveform to a central cardiovascular waveform on the basis of a plurality of model parameters. A time record is obtained using a non-invasive blood pressure sensor disposed at a solitary position periphery of the cardiovascular system of a subject. The time record is then transformed to obtain a plurality of test central blood pressure waves, with a single test central blood pressure wave is based on each of a plurality of sets of values of the model parameters. An optimum set of values of the model parameters is then selected, based on a specified criterion applied to the plurality of test central blood pressure waves, so that the aortic circulatory waveform of the subject can be obtained.

Abstract: Methods and apparatus for measuring arterial blood pressure at an extremity of a subject. Arterial blood pressure is derived from a circulatory measurement performed on an extremity of a subject and the circulatory measurement is normalized to account for the instantaneous vertical displacement of the extremity. The vertical displacement of the extremity relative to the heart of the subject is obtained using the angular orientation of the subject's extremity. An improved photoplethysmograph can discriminate light traversing the extremity from ambient light on the basis of differential response. The apparatus may have a conducting polymer actuator for applying pressure to the extremity of the subject. A pulsatile waveform from the photoplethysmographic signal may be obtained at a plurality of externally applied pressures to calibrate the photoplethysmograph.

Abstract: A method of encoding a transmission signal to reduce multiple access interference at a receiver. A data source signal including a plurality of source symbols is received into a transmitter. The source symbols are encoded using low energy encoding forming encoded codewords. An identifying pattern is applied to the encoded codewords forming a transmission signal. In one embodiment, the identifying pattern is a unique pseudo-random pattern identifying the data source. Once the pattern has been added, multiple transmission signals can be summed together and then modulated onto a carrier wave. The transmission signals are then transmitted on the carrier wave which is at a pre-selected frequency. The low energy encoding format is such that a sequence of signals forming codewords is created. Each sequence of signals is characterized by an energy and normally a high bit consumes energy whereas a low bit requires substantially less energy.

Abstract: An apparatus and method for providing controlled heating, cooling and motion, in a device such as an active robotic automobile seat, are disclosed. A shape memory alloy (SMA) element, which changes shape upon application of a temperature change to the SMA element, is coupled to a thermoelectric device. Heat flows through the TED upon application of an electrical current through the TED. The apparatus is operable in one of a plurality of modes. In a first mode, a current is applied through the TED to cause a temperature change in the SMA element to change the shape of the SMA element. In a second mode, a current is applied to the TED to cause heat flow in a space adjacent to the apparatus. By controlling application of current to the TED, controlled motion, heating and cooling are achieved in the seat.

Abstract: Multi-channel blind system identification is utilized to identify a patient's cardiac functions without catheterization. The approach is adaptive to each patient's cardiovascular system variations. The cardiac functions can be determined by formulating an auto-regression moving average model utilizing either finite impulse response systems or a group of infinite impulse response systems. Both of these models identify the system functions by solving a set of linear equations using the least-squares method. The system input is then identified by deconvolving the system output and the estimated impulse response of each channel. These models can be augmented to obtain an estimate of the maximum order of the cardiac functions when they are unknown a priori. The approach can also be modified to obtain the cardiac functions by first resolving the distinct dynamics associated with each channel, then determining the common dynamics and ultimately determining the system input.

Abstract: A new feedback linearization approach to advanced control of single-unit and multi-unit HVAC systems is described. In accordance with the approach of the invention, this new nonlinear control includes a model-based feedback linearization part to compensate for the nonlinearity in the system dynamics. Therefore, the evaporating temperature and superheat values can be controlled by linear PI control designs to achieve desired system performance and reliability. The main advantages of the new nonlinear control approach include (1) better performance even with large model errors, (2) being able to adapt to indoor unit turn on/off operation, (3) much smaller PI control gains compared to that of current feedback PI controls, (4) much easier design procedures since there is no need for tuning the PI control gains over wide range operation.

Abstract: An apparatus and method for providing controlled heating, cooling and motion, in a device such as an active robotic automobile seat, are disclosed. A shape memory alloy (SMA) element, which changes shape upon application of a temperature change to the SMA element, is coupled to a thermoelectric device. Heat flows through the TED upon application of an electrical current through the TED. The apparatus is operable in one of a plurality of modes. In a first mode, a current is applied through the TED to cause a temperature change in the SMA element to change the shape of the SMA element. In a second mode, a current is applied to the TED to cause heat flow in a space adjacent to the apparatus. By controlling application of current to the TED, controlled motion, heating and cooling are achieved in the seat.

Abstract: A method and an apparatus for distinguishing concentrations of blood constituents among distinct vascular components in situ. The method has steps of inducing periodic vibration, characterized by a frequency, in a limb of a person in such as manner as to selectively excite a resonant response in a specified blood vessel of the person, an artery or a vein, illuminating the limb of the person with a light source, and synchronously detecting a plethysmographic signal for discriminating response attributable to the specified blood vessel.

Abstract: An innovative oil observer for estimating oil concentration and oil amount in a refrigerant compressor in a vapor compression cycle is described. The invention ensures the safe operation of the compressor by ensuring that adequate lubricant is present in the compressor. This oil observer is based on oil models for components of air conditioning and refrigeration systems. Oil models for HVAC components estimate oil mass and refrigerant mass in each component. With all component oil models and heat exchanger observers which provide the estimation of inner geometric lengths of two-phase flow heat exchangers, a system-level oil observer is established by integrating all component models. Experimental testing has been conducted to verify the performance of this oil observer for steady state operation and dynamic processes. The invention has direct applications in residential and commercial air conditioning and refrigeration systems.

Abstract: A method and an apparatus for distinguishing concentrations of blood constituents among distinct vascular components in situ. The method has steps of inducing periodic vibration, characterized by a frequency, in a limb of a person in such as manner as to selectively excite a resonant response in a specified blood vessel of the person, an artery or a vein, illuminating the limb of the person with a light source, and synchronously detecting a plethysmographic signal for discriminating response attributable to the specified blood vessel.

Abstract: A ring plethysmograph having a pressure adjustment for locally pressurizing one side of a finger thereby biasing the pressure on an artery wall so that the plethysmograph is optimally sensitive without interfering with blood flow. An auxiliary photodetector, possibly with a second light source, is disposed on the low-pressure side of the finger for two purposes: providing a noise reference for canceling noise on the plethysmograph signal, and also for providing a separate motion signal for monitoring the activity level of a patient.

Abstract: Multi-channel blind system identification is utilized to identify a patient's cardiac functions without catheterization. The approach is adaptive to each patient's cardiovascular system variations. The cardiac functions can be determined by formulating an auto-regression moving average model utilizing either finite impulse response systems or a group of infinite impulse response systems. Both of these models identify the system functions by solving a set of linear equations using the least-squares method. The system input is then identified by deconvolving the system output and the estimated impulse response of each channel. These models can be augmented to obtain an estimate of the maximum order of the cardiac functions when they are unknown a priori. The approach can also be modified to obtain the cardiac functions by first resolving the distinct dynamics associated with each channel, then determining the common dynamics and ultimately determining the system input.

Abstract: A method of encoding a transmission signal to reduce multiple access interference at a receiver. A data source signal including a plurality of source symbols is received into a transmitter. The source symbols are encoded using low energy encoding forming encoded codewords. An identifying pattern is applied to the encoded codewords forming a transmission signal. In one embodiment, the identifying pattern is a unique pseudo-random pattern identifying the data source. Once the pattern has been added, multiple transmission signals can be summed together and then modulated onto a carrier wave. The transmission signals are then transmitted on the carrier wave which is at a pre-selected frequency. The low energy encoding format is such that a sequence of signals forming codewords is created. Each sequence of signals is characterized by an energy and normally a high bit consumes energy whereas a low bit requires substantially less energy.

Abstract: A method and apparatus for telemetering data on a channel having a maximum data rate by utilizing a power efficient communication protocol is provided. The data to be telemetered comprises a number of source symbols where each source symbol is characterized by a probability of occurrence. A sequence of signals forming codewords having an energy and a length is produced. The length for the codewords is based at least on the number of symbols to be coded. Each codeword signifies a specified source symbol on the basis of a mapping between source symbols and codewords. The mapping is such that each source symbol of lower probability of occurrence is associated with a codeword of at least equal energy.

Abstract: A ring plethysmograph having a pressure adjustment for locally pressurizing one side of a finger thereby biasing the pressure on an artery wall so that the plethysmograph is optimally sensitive without interfering with blood flow. An auxiliary photodetector, possibly with a second light source, is disposed on the low-pressure side of the finger for two purposes: providing a noise reference for canceling noise on the plethysmograph signal, and also for providing a separate motion signal for monitoring the activity level of a patient.