Sensor-level MEG combined with machine learning yields robust classification of mild traumatic brain injury patients.

Objective: Diagnosis of mild traumatic brain injury (mTBI) is challenging despite its high incidence, due to the unspecificity and variety of symptoms and the frequent lack of structural imaging findings. There is a need for reliable and simple-to-use diagnostic tools that would be feasible across sites and patient populations.

Methods: We evaluated linear machine learning (ML) methods' ability to separate mTBI patients from healthy controls, based on their sensor-level magnetoencephalographic (MEG) power spectra in the subacute phase (<2 months) after a head trauma.

Traceable Reference Full Metrology Chain for Innovative Aspheric and Freeform Optical Surfaces Accurate at the Nanometer Level.

The design of innovative reference aspheric and freeform optical elements was investigated with the aim of calibration and verification of ultra-high accurate measurement systems. The verification is dedicated to form error analysis of aspherical and freeform optical surfaces based on minimum zone fitting. Two thermo-invariant material measures were designed, manufactured using a magnetorheological finishing process and selected for the evaluation of a number of ultra-high-precision measurement machines.

Healthcare attendance styles among long-term unemployed people with substance-related and mood disorders.

Background: Both increased and decreased health service usage and unmet care needs are more prevalent among unemployed people than in the general population.

Study Design: This study investigates the associations of substance-related and mood disorders among long-term unemployed people with styles of healthcare attendance in Finland.

Methods: The study material consisted of the health register information on 498 long-term unemployed people in a project screening for work disabilities.

Identification of Depression and Screening for Work Disabilities among Long-Term Unemployed People.

The study explores whether clinical screening targeted at work disabilities among long-term unemployed people reveals eligible individuals for a disability pension and the importance of depression in granting the disability pensions. A total of 364 participants of the screening project were considered as eligible to apply for disability pension. Among them, 188 were diagnosed as clinically depressed.

Spectral Reflectance Estimation Using Gaussian Processes and Combination Kernels.

This paper explores hyperspectral reflectance factor estimation using Gaussian process regression with multispectral- and trichromatic measurements. Estimations are performed in visible- (400-700 nm) or visible-near infrared (400-980 nm) wavelength ranges using the learning-based approach, where sensor and light spectral characteristics are not required. We first construct new estimation models via Gaussian processes, show connection to previous kernel-based models, and then evaluate new models by using marginal likelihood optimization within the probabilistic interpretation.

Identification of major depressive disorder among the long-term unemployed.

Purpose: Depression is a common mental health disorder among the unemployed, but research on identifying their depression in health care is scarce. The present study aimed to explore the identification of major depressive disorder (MDD) in health care on long-term unemployed and find out if the duration of unemployment correlates with the risk for unidentified MDD.

Methods: The study sample consisted the patient files of long-term unemployed people (duration of unemployment 1-35 years, median 11 years), who in a screening project diagnosed with MDD (n = 243).

Transfer standard for traceable dynamic calibration of stroboscopic scanning white light interferometer.

The reconstructed image of a moving sample always shows a distorted representation of reality. Therefore, one needs to calibrate, for example, out-of-plane nano-videos for quality control of nano-microelectromechanical systems (N-MEMS). Here we discuss how to calibrate and obtain confidence limits for stroboscopic scanning white light interferometry (SSWLI) data when there are differences in speed and amplitude across the field of view.

Spectral imaging using consumer-level devices and kernel-based regression.

Hyperspectral reflectance factor image estimations were performed in the 400-700 nm wavelength range using a portable consumer-level laptop display as an adjustable light source for a trichromatic camera. Targets of interest were ColorChecker Classic samples, Munsell Matte samples, geometrically challenging tempera icon paintings from the turn of the 20th century, and human hands. Measurements and simulations were performed using Nikon D80 RGB camera and Dell Vostro 2520 laptop screen as a light source.

Traceable methods for vertical scale characterization of dynamic stroboscopic scanning white-light interferometer measurements.

Stroboscopic scanning white-light interferometry (SSWLI) can be used for 3D imaging of oscillating samples. It allows measurement of micrometer to millimeter size samples with nanometer vertical precision. Unlike coherent light source systems the SSWLI can measure unambiguously samples with vertical steps.

Identification of alcohol abuse and transition from long-term unemployment to disability pension.

Aims: The aim of the study was to reveal potential gaps and inconsistencies in the identification of alcohol abuse in health care and in employment services and to analyse the granting of disability pensions with respect to the alcohol abuse identification pattern.

Methods: The material consisted of documentary information on 505 long-term unemployed subjects with low employability sent to the development project entitled 'Eligibility for a Disability Pension' in 2001-2006 in Finland. The dichotomous variables 'Alcohol abuse identified in employment services' and 'Alcohol abuse identified in health care' were cross-tabulated to obtain a four-class variable 'Alcohol abuse identification pattern'.

Evaluating logarithmic kernel for spectral reflectance estimation-effects on model parametrization, training set size, and number of sensor spectral channels.

In this work, we evaluate the conditionally positive definite logarithmic kernel in kernel-based estimation of reflectance spectra. Reflectance spectra are estimated from responses of a 12-channel multispectral imaging system. We demonstrate the performance of the logarithmic kernel in comparison with the linear and Gaussian kernel using simulated and measured camera responses for the Pantone and HKS color charts.

Identifying diagonal cutter marks on thin wires using 3D imaging.

We present work on matching 2-mm-thick wires using optical 3D imaging methods. Marks on such small surfaces are difficult to match using a comparison microscope as this 2D imaging method does not provide height data about the sample surface. Moreover, these 2D microscopy images may be affected by illumination.

Link functions and Matérn kernel in the estimation of reflectance spectra from RGB responses.

We evaluate three link functions (square root, logit, and copula) and Matérn kernel in the kernel-based estimation of reflectance spectra of the Munsell Matte collection in the 400-700 nm region. We estimate reflectance spectra from RGB camera responses in case of real and simulated responses and show that a combination of link function and a kernel regression model with a Matérn kernel decreases spectral errors when compared to a Gaussian mixture model or kernel regression with the Gaussian kernel. Matérn kernel produces performance similar to the thin plate spline model, but does not require a parametric polynomial part in the model.

Stroboscopic scanning white light interferometry at 2.7 MHz with 1.6 µm coherence length using a non-phosphor LED source.

Stroboscopic scanning white light interferometry (SSWLI) allows precise three dimensional (3D) measurements of oscillating samples. Commercial SSWLI devices feature limited pulsing frequency. To address this issue we built a 400-620 nm wideband 150 mW light source whose 1.

Stroboscopic supercontinuum white-light interferometer for MEMS characterization.

We used a supercontinuum-based scanning white-light interferometer to characterize the oscillation of a MEMS device. The output of a commercially available supercontinuum light source (FiberWare Ilum II USB) was modulated to achieve stroboscopic operation. By synchronizing the modulation frequency of the source to the sample oscillation, dynamic 3-D profile measurements were recorded.

Evaluation and unification of some methods for estimating reflectance spectra from RGB images.

The problem of estimating spectral reflectances from the responses of a digital camera has received considerable attention recently. This problem can be cast as a regularized regression problem or as a statistical inversion problem. We discuss some previously suggested estimation methods based on critically undersampled RGB measurements and describe some relations between them.

Regularized learning framework in the estimation of reflectance spectra from camera responses.

For digital cameras, device-dependent pixel values describe the camera's response to the incoming spectrum of light. We convert device-dependent RGB values to device- and illuminant-independent reflectance spectra. Simple regularization methods with widely used polynomial modeling provide an efficient approach for this conversion.