A data collecting device includes a receiver configured to receive an optical signal; an optical-to-electrical converter configured to convert the optical signal received by the receiver into an electrical signal; an analog-to-digital converter configured to convert the electrical signal into a digital signal; a data reducing circuit configured to reduce the digital signal output from the analog-to-digital converter; and a transmitter configured to transmit, to a managing device that manages the data collecting device, a signal obtained by reducing the digital signal by the data reducing circuit.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A data collecting device comprising: a receiver configured to receive an optical signal; an optical-to-electrical converter configured to convert the optical signal received by the receiver into an electrical signal; an analog-to-digital converter configured to convert the electrical signal into a digital signal; a data reducing circuit configured to reduce the digital signal output from the analog-to-digital converter; and a transmitter configured to transmit, to a managing device that manages the data collecting device, a signal obtained by reducing the digital signal by the data reducing circuit. 2. The data collecting device according to claim 1, wherein the data reducing circuit includes a characteristic-amount extracting circuit that has a reconfigurable-layered configuration and includes an input layer, an output layer including a smaller number of multi-input single-output units than a number of multi-input single-output units included in the input layer, and a hidden layer provided between the input layer and the output layer and that is configured to map the signal output by the analog-to-digital converter to output-characteristic-amount data provided for analysis and to be output, based on the results of executing machine learning on coupling weight coefficients to be used between the layers, a comparing circuit configured to compare the output-characteristic-amount data output by the characteristic-amount extracting circuit with normal-characteristic-amount data, and a transmission-enable/disable control circuit configured to discard the output-characteristic-amount data when the comparing circuit determines that the output-characteristic-amount data is close to the normal-characteristic-amount data and transmit the output-characteristic-amount data to the managing device via the transmitter as the signal obtained by the reduction when the output-characteristic-amount data is likely to be different from the normal-characteristic-amount data. 3. The data collecting device according to claim 2, wherein the characteristic-amount extracting circuit includes a layered neural network. 4. The data collecting device according to claim 1, further comprising: an active-scanning-result collecting circuit including a specific-pattern extracting circuit configured to extract, from an input signal, a specific-pattern region in which specific patterns for active scanning are stored and a second characteristic-amount extracting circuit configured to reduce data indicating the specific-pattern region and output by the specific-pattern extracting circuit and transmit, as the signal obtained by the reduction, a signal obtained by reducing the data via the transmitter; and a switching circuit configured to switch, based on an active-scanning-state notification from the managing device, whether the signal output by the analog-to-digital converter is transferred to the data reducing circuit or transferred as the input signal to the specific-pattern extracting circuit. 5. The data collecting device according to claim 4, wherein the second characteristic-amount extracting circuit has a reconfigurable-layered configuration and includes an input layer, an output layer including a smaller number of multi-input single-output units than a number of multi-input single-output units included in the input layer, and a hidden layer provided between the input layer and the output layer and is configured to map the data indicating the specific-pattern region to characteristic-amount data provided for analysis and active scanning and to be output, based on the results of executing machine learning on coupling weight coefficients provided for the active scanning and to be used between the layers and is configured to output the characteristic-amount data as the signal obtained by the reduction. 6. The data collecting device according to claim 2, wherein the characteristic-amount extracting circuit reduces dimensions of input data and map data obtained by reducing the dimensions of the input data to the characteristic-amount data to be output. 7. An optical transmission system comprising: a plurality of data collecting devices, each of which is installed in a node of an optical network and comprises a receiver configured to receive an optical signal, an optical-to-electrical converter configured to convert the optical signal received by the receiver into an electrical signal, an analog-to-digital converter configured to convert the electrical signal into a digital signal, a data reducing circuit configured to reduce the digital signal output from the analog-to-digital converter, and a transmitter configured to transmit, to a managing device that manages the data collecting device, a signal obtained by reducing the digital signal by the data reducing circuit; and the managing device configured to include a memory and a processor coupled to the memory and to analyze an abnormal state of characteristic-amount data that is among characteristic-amount data transmitted by the plurality of data collecting devices and is at least likely to be different from a normal state. 8. The optical transmission system according to claim 7, wherein the memory is a data accumulation memory configured to store characteristic-amount data received from the plurality of data collecting devices and including an abnormal state, and the processor is a multidimensional data analyzing processor configured to analyze the reduced data accumulated in the data accumulation memory and to output an analysis result.