Abstract: An internal combustion engine includes: a cylinder including a thrust region and an anti-thrust region; and a plurality of concave portions formed in a belt-like central region including a central portion in the axial direction of the cylinder and extending along the circumferential direction on an inner wall surface. In the central region, the number of concave portions formed in a first partial region having a first predetermined width along the circumferential direction of the thrust region and the number of concave portions formed in a second partial region having a second predetermined width that is smaller than the first predetermined width along the circumferential direction of the anti-thrust region is smaller than the number of concave portions formed in other regions of the central region.

Abstract: A transmission apparatus causes a digital-to-analog conversion unit to perform digital-to-analog conversion on transmission signals pre-equalized by using a compensation filter, then converts electrical signals into optical signals, and outputs the optical signals. A receiving apparatus converts the received optical signals into received electrical signals, then performs analog-to-digital conversion, and demodulates the received signals. A scale estimation unit calculates a slope near an amplitude 0 in a correlation between an amplitude distribution of the pre-equalized transmission signals and an amplitude distribution of the received signals. A scale unit scales amplitude of the received signals on the basis of the calculated slope. A coefficient estimation unit calculates a filter coefficient of the compensation filter on the basis of the pre-equalized transmission signals and the scaled received signals.

Abstract: A receiver convolves an impulse response for compensating for frequency characteristics and a complex impulse response for wavelength dispersion compensation with each of a real component and an imaginary component of each polarized wave of a reception signal. For each polarized wave, the receiver performs complex signal processing of multiplying the imaginary component by the imaginary unit, then branching the resulting component, and adding one imaginary component to the real component. For each polarized wave, the receiver uses, as input signals, the real component and the imaginary component of each polarized wave after complex signal processing and the phase conjugates of them.

Abstract: An aspect of the present invention is a communication system including: an encoding unit configured to transform an input symbol sequence into an output symbol sequence, the input symbol sequence being a sequence of first symbols, the output symbol sequence being a sequence of second symbols; and a decoding unit configured to transform the output symbol sequence into the input symbol sequence in accordance with a decoding-side transformation mapping for transforming the output symbol sequence into the input symbol sequence that is a transformation source for the output symbol sequence, wherein the encoding unit transforms the input symbol sequence into the output symbol sequence in accordance with encoding-side transformation destination candidate information, the input symbol sequence, and a transformation probability, the encoding-side transformation destination candidate information being information indicating candidates of a transformation destination for the input symbol sequence, the transformation pro

Abstract: A waveguide estimation device includes: a time window processing unit that multiplies time-series tap coefficients of an adaptive filter by a time window function; and an estimation unit that estimates at least one of a differential group delay in a frequency series or a time series and a polarization dependent loss in a frequency series or a time series based on the time-series tap coefficients in a time window. The estimation unit may estimate at least one of the differential group delay in a frequency series or a time series and the polarization dependent loss in a frequency series or a time series based on a tap coefficient exceeding a lower limit threshold value or falling below an upper limit threshold value among the time-series tap coefficients in a time window. The estimation unit may estimate the average value of the differential group delays in a frequency series or a time series.

Abstract: A glass fiber according to the present invention is suitable for preventing filament breakage and suitable for being stably produced for a long term, and has a ß-OH value of 0.02 mm?1 or more and less than 0.55 mm?1. The preferred content of SO3 is more than 0 ppm and 70 ppm or less on a mass basis. The glass fiber is preferably substantially free of As and Sb. SO3 can be supplied to a glass raw material as, for example, a sulfuric acid salt of an alkali metal or an alkaline-earth metal.

Abstract: The present disclosure includes: a magnetic member configured to cause a large Barkhausen effect; a power generation coil disposed so as to be wound around the magnetic member; and soft magnetic members formed at both end portions of the magnetic member so as to be in contact with the magnetic member and so as to press the magnetic member. Consequently, evenness of a magnetic flux density inside the magnetic member is increased, and the large Barkhausen effect is stably caused, whereby a highly stable power generation element is obtained.

Abstract: A gas safety device includes: a flow path; a flow rate measurement unit for measuring a flow rate of gas in the flow path; an absolute pressure sensor inside the flow path for measuring an absolute pressure of the gas; an absolute pressure sensor outside the flow path for measuring an absolute pressure of atmospheric pressure; a gas pressure determination unit for measuring a change in gas supply pressure from the absolute pressure of the gas and the absolute pressure of atmospheric pressure measured by the absolute pressure sensor and the absolute pressure sensor, respectively; a shutoff valve for shutting off the flow path; and a control circuit for: (i) controlling the flow rate measurement unit; and (ii) causing the shutoff valve to shut off the flow path when determining an abnormality from the flow rate of the gas or the change in gas supply pressure.

Abstract: An internal combustion engine includes: a cylinder including a thrust region and an anti-thrust region; and a plurality of concave portions formed in a belt-like central region including a central portion in the axial direction of the cylinder and extending along the circumferential direction on an inner wall surface. In the central region, the number of concave portions formed in a first partial region having a first predetermined width along the circumferential direction of the thrust region and the number of concave portions formed in a second partial region having a second predetermined width that is smaller than the first predetermined width along the circumferential direction of the anti-thrust region is smaller than the number of concave portions formed in other regions of the central region.

Abstract: According to an aspect of the present invention, an optical signal control apparatus controls a compensation coefficient of an equalizer of an optical transmitter including the equalizer of a symbol period interval and a digital-to-analog converter (DAC) operating at a symbol period interval sampling rate and having a sampling phase adjustment function, and the sampling phase of the DAC. The optical signal control apparatus includes a skew calculation unit configured to calculate a sampling phase amount from a group delay difference between an in-phase component and a quadrature component based on characteristic information of a device and a transmission path and to output the calculated sampling phase amount to the DAC and a compensation coefficient calculation unit configured to calculate the compensation coefficient in which a phase characteristic of a Nyquist frequency of the DAC is 0 or an integer multiple of ? and to output the calculated compensation coefficient to the equalizer.

Abstract: A three-terminal capacitor includes a main body having a cylindrical or substantially cylindrical shape extending in a first direction and including first and second inner electrodes alternately laminated together with dielectric layers interposed therebetween, a pair of first outer electrodes on two end surfaces of the main body in the first direction and electrically connected to the first inner electrodes, and a second outer electrode electrically connected to the second inner electrodes. The main body includes a projecting portion projecting in a direction perpendicular or substantially perpendicular to the first direction at a position between the pair of first outer electrodes. The second outer electrode is provided on one surface of the projecting portion viewable when viewed in the first direction.

Abstract: There is provided an encoding circuit used for coherent digital signal processing, including: a serial-parallel circuit that divides input data into a plurality of pieces of divided data by serial-parallel conversion; a plurality of encoders that adds an error correction code to the divided data and encodes the divided data; and a bit conversion circuit that converts a bit sequence in order to make an amount of noise generated by a communication channel non-uniform among the plurality of pieces of divided data encoded by each of the plurality of encoders.

Abstract: An optical transmission system, in which an optical transmission apparatus and an optical reception apparatus are provided, includes a coefficient determination unit configured to optimize, based on a reception signal received by the optical reception apparatus, a coefficient to be used to compensate for deterioration according to characteristics of each device configuring a transmission path between the optical transmission apparatus and the optical reception apparatus, and a device characteristic estimation unit configured to estimate the characteristics of each device by using the optimized coefficient.

Abstract: A tentative decision is made for symbols on the basis of a received signal and a decision threshold, and a tentative decision signal including a sequence of the symbols is output. A scale value indicating a rate of increase or reduction of the received signal or a threshold change rate indicating a degree of change in the decision threshold is updated so that an appearance frequency of each of symbols included in the tentative decision signal matches an appearance frequency of each of symbols in a reference signal obtained by modulating a transmitted signal with a modulation method used in transmission which is shared between a transmitting side and a receiving side, and an SN ratio is calculated using the scale value or the threshold change rate when a degree of agreement between the appearance frequencies is within a predetermined permissible range.

Abstract: An adaptive equalizer includes an updating unit that updates a step size of a vector of a tap coefficient used for controlling an adaptive filter based on a time-series update vector in accordance with a time-series input and output of the adaptive filter that tracks a polarization state of an optical signal received by a coherent optical receiver. The updating unit updates the step size based on a DC gain of the update vector. The updating unit may update the step size for each update vector component based on a DC gain for each update vector component.

Abstract: An aspect of the present invention is an adaptive equalization filter for an optical transmission system, including: a main signal filter; and a coefficient computation unit that updates the filter coefficient of the main signal filter. The pre-stage filter and the post-stage filter receive a sample of the main signal as an input. The pre-stage coefficient computation unit obtains the filter coefficient of the pre-stage filter by feedback control using the gradient method. The post-stage coefficient computation unit obtains the filter coefficient of the post-stage filter by feedforward control. The convolution computation unit obtains the filter coefficient of the main signal filter by convolution computation of the filter coefficient of the pre-stage filter obtained by the pre-stage coefficient computation unit and the filter coefficient of the post-stage filter obtained by the post-stage coefficient computation unit.

Abstract: An optical transmitter generates symbols for transmission by applying a predetermined coding method to each of m-valued transmission symbols generated from transmission data, generates signal light by performing optical modulation on the basis of the symbols for transmission, and transmits the signal light. An optical receiver generates a series of digital signals from the received signal light, detects coded symbols by applying predetermined digital signal processing to the series of digital signals, decodes the m-valued transmission symbols from the detected coded symbols, and restores the transmission data from the decoded m-valued transmission symbols.

Abstract: The symbol determination device generates the plurality of estimated reception symbol sequences on the basis of the estimated transfer function of the transmission line represented by the tap gain value applied to each tap of the nonlinear filter including the plurality of taps and the plurality of candidate symbol sequences, determines the transmission symbol by the maximum likelihood sequence estimation on the basis of the determination target reception symbol sequence obtained from the reception signal sequence and each of the plurality of estimated reception symbol sequences, identifies the estimated transmission symbol corresponding to the determination target reception symbol sequence, calculates the new tap gain values on the basis of the determination target reception symbol sequence and the identified estimated transmission symbol sequence, updates the estimated transfer function by applying the calculated tap gain values to the taps of the transmission line estimation unit, and selects the tap to be

Abstract: A communication device includes an amplitude conversion unit configured to generate a symbol sequence according to a bit sequence, a distribution matching unit configured to add redundant bits to the symbol sequence through probabilistic amplitude shaping (PAS) coding, an insertion unit configured to insert a pilot symbol into the symbol sequence to which the redundant bits have been added and transmit the symbol sequence into which the pilot symbol has been inserted to a transmission path, and a control unit configured to acquire information on the transmission path and change, according to the information on the transmission path, allocation of the redundancy of the PAS coding and the redundancy of the pilot symbol in a range of redundancy that is able to be allocated depending on a predetermined throughput.

Abstract: A signal processing apparatus includes: a coefficient update unit configured to approximate a characteristic of a transmission line of an optical signal by a first tap coefficient vector of which an L0 norm is a predetermined value or less; a zeroing unit configured to generate a second tap coefficient vector by replacing, with 0, a tap coefficient of which an absolute value is less than a threshold among tap coefficients of the first tap coefficient vector; and an adaptive filter configured to perform, based on the second tap coefficient vector, adaptive equalization processing on a digital signal corresponding to an optical signal received via the transmission line.