Proposal for post hoc quality control in instrumented motion analysis using markerless motion capture: development and usability study

BACKGROUND: Instrumented assessment of motor symptoms has emerged as a promising extension to the clinical assessment of several movement disorders. The use of mobile and inexpensive technologies such as some markerless motion capture technologies is especially promising for large-scale application but has not transitioned into clinical routine to date. A crucial step on this path is to implement standardized, clinically applicable tools that identify and control for quality concerns. OBJECTIVE: The main goal of this study comprises the development of a systematic quality control (QC) procedure for data collected with markerless motion capture technology and its experimental implementation to identify specific quality concerns and thereby rate the usability of recordings. METHODS: We developed a post hoc QC pipeline that was evaluated using a large set of short motor task recordings of healthy controls (2010 recordings from 162 subjects) and people with multiple sclerosis (2682 recordings from 187 subjects). For each of these recordings, 2 raters independently applied the pipeline. They provided overall usability decisions and identified technical and performance-related quality concerns, which yielded respective proportions of their occurrence as a main result. RESULTS: The approach developed here has proven user-friendly and applicable on a large scale. Raters' decisions on recording usability were concordant in 71.5%-92.3% of cases, depending on the motor task. Furthermore, 39.6%-85.1% of recordings were concordantly rated as being of satisfactory quality whereas in 5.0%-26.3%, both raters agreed to discard the recording. CONCLUSIONS: We present a QC pipeline that seems feasible and useful for instant quality screening in the clinical setting. Results confirm the need of QC despite using standard test setups, testing protocols, and operator training for the employed system and by extension, for other task-based motor assessment technologies. Results of the QC process can be used to clean existing data sets, optimize quality assurance measures, as well as foster the development of automated QC approaches and therefore improve the overall reliability of kinematic data sets

A \u27Crying Wolf\u27 Game of Interspecific Kleptoparasitic Mutualism

We model a potentially mutualistic interaction between a species making antipredator alarm calls and a species which eavesdrops on those calls. Callers may or may not make deceptive alarm calls in order to kleptoparasitize food from eavesdroppers, which in turn may either heed or ignore all alarm calls. The two most likely outcomes in our model are either maximally deceptive callers and maximally trusting eavesdroppers, or persistently cycling strategy frequencies. The latter is favoured by low predator density, low density of any alternative honest alarm-calling species, ability of eavesdroppers to preferentially heed calls when costs of doing so are low and, in some cases, low food availability

Orthogonal frequency division multiplexing (OFDM) in photonic communications

OFDM has emerged as a promising modulation technique in long-haul and access optical networks because of a number of advantages: Scalable spectrum partitioning, good spectral efficiency, dispersion tolerance, and a natural suitability for software-defined transmission. However, there are also issues inherent in OFDM: High peak-to-average power ratio making the system more susceptible to nonlinearity, sensitivity to frequency offset and phase noise, and the required computational complexity. With the advent of powerful digital signal processors and by exploiting all-optical signal processing, some of these obstacles can be overcome

All-optical real-time OFDM transmitter and receiver

OFDM has emerged as a promising modulation technique in long-haul and access optical networks. The computational complexity of the format can be met with powerful digital signal processors, and especially by exploiting all-optical signal processing

All-optical FFT signal processing of a 10.8 Tb/s single channel OFDM signal

OFDM data with line rates at 10.8 Tbit/s is generated and decoded with a real-time alloptical FFT receiver

Single-laser 32.5 Tbit/s Nyquist-WDM

Single-laser 32.5 Tbit/s 16QAM Nyquist-WDM transmission with 325 carriers over 227 km at a net spectral efficiency of 6.4 bit/s/Hz is reported