Effect of head model on Monte Carlo modeling of spatial sensitivity distribution for functional near-infrared spectroscopy

Modeling Light propagation within human head to deduce spatial sensitivity distribution(SSD)is important for Near-infrared spectroscopy(NIRS)/imaging(NIRI)and diffuse correlation tomography.Lots of head models have been used on this issue,including layered head model,artificial simplified head model,MRI slices described head model,and visible human head model.Hereinto,visible Chinese human(VCH)head model is considered to be a most faithful presentation of anatomical structure,and has been highlighted to be employed in modeling light propagation.However,it is not practical for all researchers to use VCH head models and actually increasing number of people are using magnet resonance imaging(MRI)head models.Here,all the above head models were simulated and compared,and we focused on the effect of using di®erent head models on predictions of SSD.Our results were in line with the previous reports on the effect of cerebral cortex folding geometry.Moreover,the in fluence on SSD increases with thefidelity of head models.And surprisingly,the SSD percentages in scalp and gray matter(region of interest)in MRI head model were found to be 80%and 125%higher than in VCH head model.MRI head models induced nonignorable discrepancy in SSD estimation when compared with VCH head model.This study,as we believe,is the first to focus on comparison among full serials of head model on estimating SSD,and provided quantitative evidence for MRI head model users to calibrate their SSD estimation.

Missile robust gain scheduling autopilot design using full block multipliers

Reduction of conservatism is one of the key and difficult problems in missile robust gain scheduling autopilot design based on multipliers.This article presents a scheme of adopting linear parameter-varying（LPV） control approach with full block multipliers to design a missile robust gain scheduling autopilot in order to eliminate conservatism.A model matching design structure with a high demand on matching precision is constructed based on the missile linear fractional transformation（LFT） model.By applying full block S-procedure and elimination lemma,a convex feasibility problem with an infinite number of constraints is formulated to satisfy robust quadratic performance specifications.Then a grid method is adopted to transform the infinite-dimensional convex feasibility problem into a solvable finite-dimensional convex feasibility problem,based on which a gain scheduling controller with linear fractional dependence on the flight Mach number and altitude is derived.Static and dynamic simulation results show the effectiveness and feasibility of the proposed scheme.

Photon penetration depth in human brain for light stimulation and treatment:A realistic Monte Carlo simulation study

Light has been clinically utilized as a stimulation in medical treatment,such as Low-level laser therapy and photodynamic thenapy,which has been more and more widely accepted in public.The penetration depth of the treatment light is important for precision treatment and safety control.The isue of light penetration has been highlighted in biomedical optics field for decades.However,quantitative research is sparse and even there are conflicts of view on the capability of near-infrared light penet ration into brain tissue.This study attempts to quantitatively revisit this issue by innovative high-realistic 3D Monte Caro modeling of stimulated light penetnation within high precision Visible Chinese human head.The properties of light,such as its wave-length,ilumination profle and size are concern in this study.We made stra ightforward and quantitative comparisons among the ffects by the light properties(i.e.,wavelengths:660,810 and 980 nn;beam types:Gaussi an and flat beamn;bear dianeters:0,2,4 and 6 cm)which are in the range of light treatment.The findings include about 3%of light dosage within brain tisue;the combination of Gaussian beam and 810nm light make the max imum light penetration(>5cm),which allows light to cross through gray matter into white mater.This study offered us,the first time as we know,quantitative guide for light stimulation parameter optimization in medical treatment.