A method and a system for terahertz detection, using at least a first and a second electrodes separated by a centro-symmetric material. The system comprises at least a first and a second electrodes with conductive pads for connection to a voltage source, separated by a centro-symmetric material; the method comprising second harmonic generation in the centro-symmetric material by overlapping of a probe and a terahertz beams.

A device can detect radio frequency (RF) signals in a physical environment using one or more antennas of a device. The device can generate RF measurements based on the RF signals. The device can also generate a multi-dimensional model of the physical environment based on sensor information from one or more sensors of the device. For example, the multi-dimensional model could be a 2D or 3D floor plan of the physical environment. The device can then map the RF measurements to locations in the multi-dimensional model. In some implementations, the device can configure a graphical user interface to display the multi-dimensional model and the mapping. For example, the display could represent a heat map for determining a change to a network. Other aspects are also described and claimed.

An example apparatus includes: calibration circuitry configured to determine a second current at a second terminal of a second impedance circuit based on a first parasitic capacitance, a first impedance value, a third impedance value, a first voltage, and a second voltage; determine a third voltage at a second terminal of a second impedance circuit based on the first parasitic capacitance, a second impedance value, the third impedance value, the second voltage, and the second current; and determine a second parasitic capacitance between the second terminal of the second impedance circuit and the second terminal of a fifth impedance circuit based on the second current, the third voltage, a third current at the second terminal of the fifth impedance circuit, and a fourth voltage at the second terminal of the fifth impedance circuit.

A computer-readable recording medium stores therein an information processing program that causes a computer to execute a process in a density functional theory calculation in which electron density is repeatedly updated. The process includes repeatedly updating the electron density until a first condition is satisfied, the first condition being that a difference ratio of a first value of a total electron energy to a second value of the total electron energy is not more than a first threshold, the first value of the total electron energy being based on a first value of the electron density updated most recently, and the second value of the total electron energy being based on a second value of the electron density updated in an initial period.

A computer-readable recording medium stores therein an information processing program that causes a computer to execute a process in a density functional theory calculation in which electron density is repeatedly updated. The process includes repeatedly updating the electron density until a first condition is satisfied, the first condition being that a difference ratio of a first value of a total electron energy to a second value of the total electron energy is not more than a first threshold, the first value of the total electron energy being based on a first value of the electron density updated most recently, and the second value of the total electron energy being based on a second value of the electron density updated in an initial period.

A method of focusing radio wave energy at a focusing target point, which is performed by a processor, may comprise: generating an electromagnetic numerical model of an object including the focusing target point; predicting radio wave focusing points inside the object using radio wave characteristic information of a radio wave radiation module and the electromagnetic numerical model; optimizing one or more focusing parameters such that radio wave energy reaching one or more unnecessary focusing points other than the focusing target point among the radio wave focusing points inside the object is reduced; and radiating radio waves based on the optimized focusing parameters.