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Purpose This study aims to leverage inertial sensors via a walk test to associate kinematic variables with functional assessment results among walkable subjects with chronic stroke. Design/methodology/approach Adults with first-ever stroke survivors were recruited for this study. First, functional assessments were obtained by using Fugl–Meyer Assessment for lower extremity and Berg balance scales. A self-assembled inertial measurement system obtained walking variables from a walk test after being deployed on subjects’ affected limbs and lower back. The average walking speeds, average range of motion in the affected limbs and a new gait symmetry index were computed and correlated with the two functional assessment scales using Spearman’s rank correlation test. Findings The average walking speeds were moderately correlated with both Fugl–Meyer assessment scales (γ = 0.62, p < 0.01, n = 23) and Berg balance scales (γ = 0.68, p < 0.01, n = 23). After being modified by the subjects’ height, the new gait symmetry index revealed moderate negative correlations with the Fugl–Meyer assessment scales (γ = −0.51, p < 0.05) and Berg balance scales (γ = −0.52, p < 0.05). The other kinematics failed to correlate well with the functional scales. Practical implications Neuromotor and functional assessment results from inertial sensors can facilitate their application in telemonitoring and telerehabilitation. Originality/value The average walking speeds and modified gait symmetry index are valuable parameters for inertial sensors in clinical research to deduce neuromotor and functional assessment results. In addition, the lower back is the optimal location for the inertial sensors.

The fabrication of Fresnel focusing lenses operating at frequencies of 100 and 200 MHz was investigated in order to enhance the focusing efficiency of ultrasonic energy. The effects of process parameters on the four-level Fresnel lens profiles were discussed to find a most feasible fabrication procedure through these experiments. The quality of Fresnel lenses was improved when two-and three-mask processes using SiO2 film as the hard mask were employed. Besides, a better side-wall profile of Fresnel lens was obtained by using the three-mask process as compared to the two-mask one.

Breast cancer remains the most frequently diagnosed cancer and is the leading cause of neoplastic disease burden for females worldwide, suggesting that effective therapeutic and/or diagnostic strategies are still urgently needed. In this study, a type of indocyanine green (ICG) and camptothecin (CPT) co-loaded perfluorocarbon double-layer nanocomposite named ICPNC was developed for detection and photochemotherapy of breast cancer. The ICPNCs were designed to be surface modifiable for on-demand cell targeting and can serve as contrast agents for fluorescence diffuse optical tomography (FDOT). Upon near infrared (NIR) irradiation, the ICPNCs can generate a significantly increased production of singlet oxygen compared to free ICG, and offer a comparable cytotoxicity with reduced chemo-drug dosage. Based on the results of animal study, we further demonstrated that the ICPNCs ([ICG]/[CPT] = 40-/7.5-μM) in association with 1-min NIR irradiation (808 nm, 6 W/cm2) can provide an exceptional anticancer effect to the MDA-MB-231 tumor-bearing mice whereby the tumor size was significantly reduced by 80% with neither organ damage nor systemic toxicity after a 21-day treatment. Given a number of aforementioned merits, we anticipate that the developed ICPNC is a versatile theranostic nanoagent which is highly promising to be used in the clinic.

To assess cutting-tools degradation, mounted accelerometers and current clamp probes were used to acquire machining vibration for both the band-saw machine and the drilling machine, of which a structural-steel machining center is composed. Significant features were first extracted through spectral analysis, and tool degradation assessment was conducted through using a supervised learning scheme, self-organizing map. The results reveal that 10% remaining useful life can be predicted before the band-saws and drills wore out.

In this paper, signal analysis techniques based on Teager-Kaiser energy operation and envelope spectra for fault detection of the discharge valve of a reciprocating compressor is proposed. The method can accurately identify the existing fault of vibration signal features that it simulated by the synthetic signals. A two-phase study was designed to explore the signals simulation and the experimental validation. Signals simulation, which is based on the operation of a reciprocating compressor, and experiment design, which uses three conditions. The first stage is to simulate the operation of the reciprocating compressor, which is to simulate a synthetic signal for the cycle and impact. The synthetic signal is composed of a noise, square wave, and pulse wave. In this study, the synthetic signal is signal-processed by the Teager-Kaiser energy operator and the envelope spectrum that they can effectively extract feature signal and the noise almost is eliminated. The second stage is applied to the signal processing technique proposed in the first stage. Experimental verification of experiment design by the different operating conditions of reciprocating compressor valves. Through the above analysis technology, it is proved that the synthetic signal can be eliminated the background noise to obtain the feature signal. The feasibility of the proposed approach is verified by simulation results, the experiment is to validate with the measurement signals from a six-cylinder reciprocating compressor under different valve conditions. Simulations and experimental results support the proposed technology positively.

This study presents a novel measurement scheme for near-infrared diffuse optical tomography through employing square-wave driving light sources to simultaneously obtain amplitude and phase delay data of multiple sinusoids for the reconstruction of optical-coefficient images.

In this study, we proposed and implemented a ring-scanning mechanism in the prone position for application in breast tumour detection. The current scanning module using two zones with three light sources in each zone enables the acquisition of 36 source and 30 detection data (36S × 30D) items during the optical information collection phase. This study employed only three photomultiplier tubes (PMTs), instead of 30 PMTs used in a fixed model. In particular, the circular scanning of source-and-detection module actually behaves as more channels and can acquire more optoelectrical data as the scanning module operates in a fractional motion of a single channel-to-channel span. In this study, the optoelectrical measurement system was first calibrated; then, the feasibility of optical-coefficient image reconstruction was verified using several heterogeneous cylindrical phantoms. The reconstructed μ a and μ s ′ images through multilayer scanning presented good outcomes, implying that the developed system is promising for 3D scanning of breasts. In a quantitative analysis, the contrast-to-noise ratios of the μ a and μ s ′ images (6.00 and 4.97, respectively) for the flexible scanning scheme were superior to those derived for the fixed scheme (5.05 and 4.31, respectively). This indicates that the higher amount of detection information obtained through the proposed scanning module can enhance the spatial resolution of the reconstructed images while retaining an acceptable scanning time.

Osseointegration is the key to the success of surgery of dental implantation. In this study, we proposed, implemented and explored a handheld and noncontact electromagnetic-type stability assessment device for the use after surgery. The device with two pairs of dual inductors incorporating with a driving signal of swept wavelets was first proposed. This detection device feeds 200–10 kHz of alternating current into an inductor to produce swept broadband magnetic flux and excite the implant structure with a magnetic pole. The implant vibration causes magnetic-flux changes and generates an induced electromotive force. The implant structure resonance frequency (RF) can be characterized to exhibit osseointegration status by evaluating the frequency response function. In vitro bone block experiment and in vivo animal testing were performed to validate the developed device. For bone block experiment on fourteen designs, besides two cancellous bones and two cortical-shell thicknesses, four interface tissues produced using varied mixing ratios of epoxy adhesive were to imitate osseointegration progress. Further, a pilot animal test was conducted on five female New Zealand rabbits to assess implant osseointegration in live bodies. Statistical analyses for varied bone models on measured RF, and the regression analysis between the measured RF and OsstellTM ISQ for in vivo testing were performed. The correlation analysis on the built regression models shows a close relationship between the measured RFs and ISQ quotients with the determination coefficients up to over 0.9.

High focusing efficiency of a multi-level Fresnel lens is desired when it is designed and fabricated. How to estimate the focusing efficiency is an important issue after the Fresnel lens is made. W...

Diffuse optical imaging enables to reconstruct distribution of optical properties, absorption and scattering coefficients, in tissue for breast cancer detection based on diffusion equation with the help of the initial guess obtained from measured data. To estimate the initial guess of the optical-property coefficients, an analytical solution of diffusion equation can be used and compared with the measured data. The analytical solution for a homogeneous infinite medium can be obtained in the frequency domain, expressing that the photon intensity and the phase lag relative to the distance between source and detector in a linear relationship. In this study, a succinct calculation using the trigonometric relation is proposed to estimate the optical-property coefficients. A tank-type and a cylinder Lipovenoes phantoms with two concentrations of 1.25% and 2.5% are employed and measured for verification. It is found that the method proposed here shows better results and results in estimation errors of 0–14.81% for μa and 20–42% for μs′.

When a rotary machine is running, from which the acquired vibro-acoustic signals enable to reveal its operation status and health condition. The study proposed a DSP-based adaptive angular-velocity Vold-Kalman filtering order tracking (AV2KF_OT) algorithm with an online real-time nature for signal interpretation and machine condition monitoring. Theoretical derivation and numerical implementation of computation schemes are briefly introduced. An online real-time monitoring system based on the AV2KF_OT algorithm, which was implemented through both a digital signal processor and a user interface coded by using LabVIEW, was developed. Two experimental tasks were applied to justify the proposed technique, including (i) the detection of startup on the fluid-induced whirl performed through a journal-bearing rotor rig, and (ii) the separation of close orders from the measured signals of a multifunction transmission-element ball-bearing bench.

On the basis of resonance frequency analysis, a noncontact handheld assessment device that employs the vibro-acoustic technique with acoustic excitation and displacement response sensing was developed to quantify the stability of dental implants. The assessment technique employed in the developed device is superior to the magnetic sensing technique that uses an accessory for assessment. The calculated response spectra that characterized dental-structure resonance indicated the trend of osseointegration. In vitro and in vivo tests were performed to verify the performance of the developed device. For in vitro bone block testing, in addition to two cancellous bones and two thicknesses of cortical shells, interface tissues produced using different mixing ratios of resin to hardener epoxy adhesive were used to mimic the osseointegration progress. Furthermore, preliminary animal testing was conducted on rabbits to observe implant osseointegration in live bodies. Statistical analyses for varied designed bone models on measured resonance frequency, and the regression analysis between VA and Osstell™ ISQ for in vivo testing were performed. The necessary statistical analyses on various issues were considered as well as their descriptions. The developed noncontact vibro-acoustic assessment device can be used to monitor the implant stability status without having to use a mounted accessory.

The use of inertial measurement units associated with various algorithms has been proposed and developed to evaluate functional abilities and kinematics for stroke patients. In previous research, complex mathematical models were adopted successfully to clarify and to validate the functional results from different sensors. However, only a few algorithms stemmed from the process of motor recovery after a stroke or the way to administer clinical assessment scales. Based on the recovery process or how to conduct the assessment scales, the algorithmsensor based module is supposed to accurately classify clinical motor recovery status and to provide additional kinematics in stroke survivors. In this study, only one sensor is affixed on the dorsum of the affected foot to reduce the burden on a weak extremity. A special movement while in seated, extend their knee and then dorsiflex their feet, based on the motor recovery process after stroke is proposed and tested to classify Brunnstrom stages for lower extremities. After analyzing 24 participants and adopting suitable threshold values for different Brunnstrom stages, the overall accuracy is 86.8%. The ability to distinguish Brunnstrom stage II from others can even reach a 100% accuracy. The accuracies for distinguishing Brunnstrom stage III, stage IV, and stage V are 86.6%, 94 %, and 92.8%, respectively. We also analyze these misclassified data and investigate why the errors occurred. The results reveal the feasibility of the kinematics-based algorithm even using a single sensor.

A working prototype of an optical breast imaging system involving a dual-direction parallel-plate scanning scheme in combination with a mammography machine was demonstrated and applied in imaging healthy and malignant breasts in a clinical environment.

The phenomenon of fluid-induced instability existing in fluid-film bearing systems has been coped with for long time. The study aims to soothe and even eliminate the occurrence of whirl in rotary machinery by increasing the threshold of instability through the anti-swirl injection using the linear quadratic regulator based optimal control. An acceptance region was established in order to decide starting up the control process. Three case studies were carried out to illustrate the effectiveness of the control scheme. The research results demonstrate that the control scheme incorporating with the acceptance region enables to avoid the occurrence of fluid induced instability in rotary machinery. Moreover, the developed techniques can also be applied in other fluid-induced instability problems such as whip and rub, etc.

We implemented a ring-scanning mechanism in a prostrate type for breast tumor detection. Reconstructed μa and μs′ images of multi-layers scanning are presented in good outcomes, showing it’s promising for the 3D scanning of breast.

Mechanical systems under periodic loading due to rotary operation usually respond in measurements with a superposition of sinusoids whose frequencies were integer or fractional integer multiples of the reference shaft speed. When the rotary machines are running, acousto-mechanical signals acquired from the machines enable to reveal their operation status and machine conditions. The study proposed a DSP-based adaptive angular-velocity Vold-Kalman filtering order tracking (AV2KF_OT) algorithm with online real-time nature for signal interpretation and machine condition monitoring. Theoretical derivation and numerical implementation of the computation scheme was briefly introduced. An online real-time condition monitoring system based on the AV2KF_OT algorithm, which was implemented through both a digital signal processor (DSP) and a man-machine interface coded by using LabVIEW®, was developed. An experimental task, the startup detection on the fluid-induced whirl performed through a journal-bearing rotor rig, was used to justify the proposed technique.

This study is to develop an automatic classification system for lower limb Brunnstrom stage of hemiparetic patients. The measurement system is employed both IMU and sEMG to acquire the lower limb motion signals from patients. Afterward, this study extracted some useful features for the proposed rule-based classification system and compared different classification algorithms such as k-nearest neighbor, artificial neural network and support vector machine. Instead of leave one out cross validation, the leave subjects out cross validation was used to calculate the successful rate of classification. The results of the experiment on seventeen men and seven women at mean age: 60.6 ± 12.4 years after stroke for more than 6 months show that SVM (95.2%) has the highest accuracy to classify Brunnstrom stage than k-NN (89.2%) and ANN (92.3%). The robustness of this classification system was verified by training different number of subject data. According to the classification result, it can be concluded that the proposed classification system has the potential to predict the lower limb Brunnstrom stage for hemiparetic patients.

Breast tissues like fatty and fibroglandular ones are adipose mainly and possess high scattering nature, so that they diffuse and make the light approximately uniformly distribute over the measured cross-section besides absorbing to reduce the light intensity. Strong cause-and-effect relationships exist between absorption and intensity decay, and between scattering and phase delay as well. Thereby in a diffuse optical imaging system it is a general practice to estimate absorption coefficients from the measured intensity since it reflects most of the absorption property. This study aims to illustrate that both μ a and μ ′ images of breast can be reconstructed by only direct-current data reliably to a certain extent. Varied sets of phantom design with assigned absorption/scattering properties for inclusion and background were synthesized and image reconstructed to demonstrate this perspective. Moreover, we employed a slab-type diffuse optical imaging system with a dual-direction direct-current NIR measurement module, where reconstructed images were compared between with and without reflectance NIR data.

Diffuse optical imaging (DOI) is emerging as a new functional imaging modality that can be used for breast cancer screening. Due to the ill-posed inverse problem for DOI image reconstruction, regularization is essential to remedy such a drawback. In our previous study, we have successfully implemented edge-preserving regularization into image reconstruction algorithm for improving the reconstructed images. In this study, we incorporate additional anatomical image, which can be obtained from other imaging modality such as mammography or magnetic resonance imaging, although showing no tumor information, into edge-preserving regularization for further improving the reconstructed images. Reconstruction results show that the quality of reconstructed images can be significantly improved.

In clinical settings, traditional stroke rehabilitation evaluation methods are subjectively scored by occupational therapists, and the assessment results vary individually. To address this issue, this study aims to develop a stroke rehabilitation assessment system by using inertial measurement units. The inertial signals from the upper extremities were acquired, from which three quantitative indicators were extracted to reflect rehabilitation performance during stroke patients’ movement examination, i.e., shoulder flexion. Both healthy adults and stroke patients were recruited to correlate the proposed quantitative evaluation indices and traditional rehab assessment scales. Especially, as a unique feature of the study the weight for each of three evaluation indicators was estimated by the least squares method. The quantitative results demonstrate the proposed method accurately reflects patients’ recovery from pre-rehabilitation, and confirm the feasibility of applying inertial signals to evaluate rehab performance through feature extraction. The implemented assessment scheme appears to have the potential to overcome some shortcomings of traditional assessment methods and indicates rehab performance correctly.

In this presentation, we demonstrate a working prototype of an optical breast imaging system using parallel-paddle architecture with dual-direction scanning, of which the designed module can be incorporated with a mammographic system for the acquisition of optical transmission and reflection information in both directions of up-down and down-up. Additionally, the scanning module enables to move with a designated pitch to accommodate varied breast size for acquiring adequate data to reconstruct the images. Currently, continuous-wave near infrared illumination modules are used for experimentation. The feasibility will be presented by phantom test.

Diffuse optical imaging (DOI) providing functional information of tissues has drawn great attention for the last two decades. Near infrared (NIR) DOI systems composed of scanning bench, opt-electrical measurement module, system control, and data processing and image reconstruction schemes are developed for the screening and diagnosis of breast tumors. Mostly, the scanning bench belonging to fixed source-and-detector configuration limits computed image resolution to an extent. To cope with the issue, we propose, design and implement a 3D prostrate ring-scanning equipment for NIR DOI with flexible combinations of illumination and detection, and with the function of radial, circular and vertical movement without hard compression of breast tissue like the imaging system using or incorporating with X-ray mammographic bench. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel movement. Following the previous justification for synthesized image reconstruction, in the paper the validation using varied phantoms is further conducted and 3D image reconstruction for their absorption and scattering coefficients is illustrated through the computation of our in-house coded schemes. The source and detection NIR data are acquired to reconstruct the 3D images through the operation of scanning bench in the movement of vertical, radial and circular directions. Rather than the fixed configuration, the addressed screening/diagnosing equipment has the flexibility for optical-channel expansion with a compromise among construction cost, operation time, and spatial resolution of reconstructed μ a and μ s ’ images.

In this paper, preliminary simulated reconstruction results are presented to investigate the effects of geometrical mismatch between the physical and computational models on the reconstructed images. Two types of mismatch are discussed.

As optimized wavelengths are used, a nearinfrared (NIR) tomographic imaging system using multiwavelengths in continuous wave has the potential to provide accurate information of chromophores. In this paper, we discuss wavelength optimization with commercial laser diodes. Through theoretical analysis, we use the residual norm (R) and the condition number (κ) representing the uniqueness of this matrix problem (Eq. (6)) and the smooth singular-value distribution of each chromophore, respectively. The optimum wavelengths take place as large R and small κ We found 37 wavelengths in total from the 633nm-980nm range available in the market to discover optimum wavelength sets for a broad range of chromophore combinations. From a complete set of 37 wavelengths, there exist 7770 (C37 3), 66045 (C37 4), and 435897 (C37 5) combinations of three, four, and five wavelength sets, respectively, for accurately estimating chromophores (HbO2 and HbR) plus the scattering prefactor A. With the numerical calculation, top 10 wavelength sets were selected based on high R and low k. Furthermore, it is found that 650, 730, 905, 705, and 690 nm are optimal with a same part for three, four, and five wavelength sets, respectively.

For employing optimized wavelengths, a near-infrared (NIR) tomographic imaging system with multiwavelengths in a continuous wave (CW) enables us to provide accurate information of chromophores. In this paper, we discuss wavelength optimization with a selection from commercial laser diodes. Through theoretical analysis, the residual norm (R) and the condition number (κ) represent the uniqueness of a matrix problem and the smooth singular-value distribution of each chromophore, respectively. The optimum wavelengths take place for large R and small κ. We considered a total of 38 wavelengths of laser diodes in the range of 633–980 nm commercially available to discover optimum sets for a broad range of chromophore combinations. In the 38 wavelengths, there exists 501,942 (C538), 2,760,681 (C638), and 12,620,256 (C738) combinations of five, six, and seven wavelength sets, respectively, for accurately estimating chromophores (HbO2, HbR, H2O, and lipids), water, lipids, and the scattering prefactor A. With the numerical calculation, the top 10 wavelength sets were selected based on the principle of large R and small κ. In the study, the chromophore concentration for young and elderly women are investigated; finally, choosing the laser diodes with a wavelength of 650, 690, 705, 730, 870/880, 915, and 937 nm is recommended either for young or elderly women to construct a spectral NIR tomographic imaging system in the CW domain. Simulated data were used to validate the claims.

We propose and implement three-dimensional (3-D) ring-scanning equipment for near-infrared (NIR) diffuse optical imaging to screen breast tumors under prostrating examination. This equipment has the function of the radial, circular, and vertical motion without compression of breast tissue, thereby achieving 3-D scanning; furthermore, a flexible combination of illumination and detection can be configured for the required resolution. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel motion. Prior to machining and construction of the system, a synthesized image reconstruction was simulated to show the feasibility of this 3-D NIR ring-scanning equipment; finally, this equipment is verified by performing phantom experiments. Rather than the fixed configuration, this addressed screening/diagnosing equipment has the flexibilities of optical-channel expansion for spatial resolution and the dimensional freedom for scanning in reconstructing optical-property images.