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The field of implantable electronics relies on using silicon materials due to the merits of a well-established fabrication process and favorable properties; of particular interest is the surface modification of such materials. In the present study, we introduce a surface modification technique based on coatings of functionalized Parylene on silicon substrates, where the modified layers provide a defined cell adhesion capability for the resultant silicon materials/devices. Functionalization of Parylene was achieved during a one-step chemical vapor deposition (CVD) polymerization process, forming NHS ester-functionalized Parylene, and subsequent RGD attachment was enabled via a conjugation reaction between the NHS ester and amine groups. The modification procedures additionally provided a clean and gentle approach to avoid thermal excursions, intense irradiation, chemicals, or solvents that might damage delicate structures or sensitive molecules on the devices. The modification layers exhibited excellent mechanical strength on the substrate, meeting the high standards of the American Society for Testing and Materials (ASTM), and the resultant cell adherence property was verified by a centrifugation assay and the analysis of attached cell morphologies; the results collectively demonstrated robust and sustainable modification layers of the NHS ester-functionalized Parylene and confirmed that the cell-adherence property imparted by using this facile modification technique was effective. The modification technology is expected to benefit the design of prospective interface properties for silicon-based devices and related industrial products.

Improving soldiers’ resilience and recovery has always been the core of military training for all countries. Current research tends to consider stress negative, which leads to unhealthiness or unhappiness; as a result, some scholars believe that stress should be avoided or reduced as much as possible. Frankly speaking, the existence of stress is inevitable in military environments. For example, turning into a soldier from a civilian in military academy exerts great pressure on freshmen, which is necessary. In practical, the implementation of stress management courses is fragmentary and discontinuous. Such lectures focus more on theories, which could not make students truly comprehend the nature of stress. In this study, stress theory and virtual reality technology design are adopted to overcome the difficulties of current curriculum. For the stress mindset theory, some scholars believe having a stress-is-enhancing mindset will enhance physical and mental health as well as raise the happiness, while having a stress-is-debilitating mindset may cause negative effects on physical and mental health as well as decrease the happiness. Therefore, the theory of curriculum design in this study will adopt the theory of stress-is-enhancing mindset. This viewpoint emphasizes that stress mindset is a belief, and that strengthening an individual’s mentality will enhance their ability to face challenges. Through learning stress-is-enhancing mindset, military academy students can well deal with stress in the future. The course adopts a Mindset Training Program proposed by Crum [2], which includes a three-step, two-hour teaching course. In the first part, “The Paradox of Stress” introduces the possibility to make people weak or strong through the stress. In the second part, “The Power of Mindset”, the stress is specified and defined through films and examples to explain how attitudes influence individual’s psychology and physiology. In the third part, three steps to strengthen mentality are adopted. The steps aim to help new cadets adopt a positive and conscious way to strengthen mentality. The third part will include virtual reality technology, a kind of computer technology that enables participants to interact with computer-generated three-dimensional scenes. Participants can produce the same behavior and emotions as in real situations, and it takes less time. Finally, the results of this study are expected to give educators a new model for stress management, and further enhance the resilience and recovery of the military.

Surface modification layers are needed for the precise definition of surface chemistries and are equally important for durable and stable adhesive properties to ensure long-term stability and effective performance for biotechnological applications. This study demonstrates a robust modification layer that is synthesized based on chemical vapor deposition copolymerization, and the resultant coating layer is composed of the side-by-side presentation of N-hydroxysuccinimide ester and maleimide functionalities with a controlled ratio to define the immobilization accessibility of chitosan and growth factor protein (FGF-2) molecules on the substrate surface for enhancing cellular activities of stem cells. Characterizations of the copolymer modification layer showed excellent durability, including adhesive strength and thermal stability, and the layer is free of concerns for delamination and/or unacceptable deformation/debris formation that can cause potential toxicity to the surrounding biological environment. Modifications using the copolymer layer on the cell culture surface have demonstrated synergistic activity by chitosan to support the formation of spheroids and by FGF-2 to enhance the proliferation of human adipose-derived stem cells (ADSCs) within the spheroids while increasing the spheroid size and cell numbers. Healthy and flourishing growth activities were discovered for ADSCs on the modified culture surfaces, and the results are useful for potential and related stem cell research and the interfaces of biomaterials.

To solve interference in a heterogeneous network, LTE-A uses almost blank subframe (ABS) to improve channel quality of picocells at the expense of macrocell’s transmission. Many studies find the ABS ratio based on user number or traffic load. However, the issue of real-time (RT) packet delay is not well studied. We thus develop a delay-aware ABS adjustment (DA3) method to improve performance and lower packet dropping. DA3 estimates cells’ capacity to decide the ratio, and analyzes queue content to alleviate packet discard. Simulation results show that DA3 increases cells’ goodput while reducing RT packet dropping.

It is generally agreed that sound quality is one of the most difficult to measure characteristics of an electroacoustic products such as an earphone or a loudspeaker. A conventional approach used to measure people's subjective perception of these sound reproduction products is to conduct a jury test on a group of experiment participants; however, jury tests require considerable costs, including those of effort and time. As development speed and cost become strategic competitive dimensions, electroacoustic industry needs a more efficient approach to assess their newly developed products for subjective sound quality. This study developed and validated a quantitative model, the tonal harmony level (THL), that can effectively predict people's subjective perceptions of music quality. Participants' subjective perception and preference was measured for four music genres by listening to short music excerpts (8 s) in both ordinal and interval scales. The purpose of using two scales is to examine the consistency between subjective perceptions and to determine the robustness of the subjective measurements. The experimental results were very stable over the two assessment procedures, and the objective THL measure is highly correlated to subjective preference. The analysis suggests that the construction of subjective music quality prediction models should also consider music genre. Among four types of music, musical solos consisted of human vocals accompanied by a few instruments has a distinct pattern from the other three types. Thus, while R2 value of the overall regression model is 0.707, the R2 values are 0.955 and 0.901 when four music genres are categorized into two groups according to their patterns. When efficiency and accuracy were simultaneously considered, according to the results of this study, the approach of two-group categorization can be adopted.

The accuracy and fluency of a handover task affects the work efficiency of human&ndash, robot collaboration. A precise and proactive estimation of handover time points by robots when handing over assembly parts to humans can minimize waiting times and maximize efficiency. This study investigated and compared the cycle time, waiting time, and operators&rsquo, subjective preference of a human&ndash, robot collaborative assembly task when three handover prediction models were applied: traditional method-time measurement (MTM), Kalman filter, and trigger sensor approaches. The scenarios of a general repetitive assembly task and repetitive assembly under a learning curve were investigated. The results revealed that both the Kalman filter prediction model and the trigger sensor method were superior to the MTM fixed-time model in both scenarios in terms of cycle time and subjective preference. The Kalman filter prediction model could adjust the handover timing according to the operator&rsquo, s current speed and reduce the waiting time of the robot and operator, thereby improving the subjective preference of the operator. Moreover, the trigger sensor method&rsquo, s inherent flexibility concerning random single interruptions on the operator&rsquo, s side earned it the highest scores in the satisfaction assessment.

In this study, Mg x Zn 1-x O (0≤ x ≤ 0.3) semiconductor thin films and metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors were deposited on alkali-free glass substrates (NEG OA-10) using a sol-gel spin-coating process. The effect of incorporating Mg into ZnO thin films on the structural, electrical, optical, and UV photoresponse properties were investigated and photoconductive UV detectors were realized using ZnO and MgZnO thin films. Experimental results showed that the as-prepared MgZnO thin films had a polycrystalline hexagonal wurtzite phase and exhibited high transparency (≥90.0%) in the visible region. The optical bandgap of MgZnO thin films increased from 3.25 to 3.56 eV and the electrical resistivity of the thin films rose from 6.10×102 to 8.86×104 Ω-cm with increasing Mg content. In addition, We found that the MgZnO photodetectors exhibited better photocurrent generation than the pure ZnO photodetectors and the Mg 0.1 Zn 0.9 O device exhibited the highest Ion to I off ratio of 2×103.

An electrically induced bottom-up process was introduced for the fabrication of multifunctional nanostructures of polymers. Without requiring complicated photolithography or printing techniques, the fabrication process first produced a conducting template by colloidal lithography to create an interconnected conduction pathway. By supplying an electrical charge to the conducting network, the conducting areas were enabled with a highly energized surface that generally deactivated the adsorbed reactive species and inhibited the vapor deposition of poly- p-xylylene polymers. However, the template allowed the deposition of ordered poly- p-xylylene nanostructures only on the confined and negative areas of the conducting template, in a relatively large centimeter-scale production. The wide selection of functionality and multifunctional capability of poly- p-xylylenes naturally rendered the synergistic and orthogonal chemical reactivity of the resulting nanostructures. With only a few steps, the construction of a nanometer topology with the functionalization of multiple chemical conducts can be achieved, and the selected deposition process represents a state-of-the-art nanostructure fabrication in a simple and versatile approach from the bottom up.

Antifouling surfaces that are resistant to protein adsorption and cell adhesion are desirable for many biomedical devices, such as diagnostic devices, biosensors, and implants. In this study, we developed an antifouling hyperbranched polyglycerol (hPG) surface on hydroxyl poly-p-xylylene (PPX-OH). PPX-OH was deposited via chemical vapor deposition (CVD), and an hPG film was then developed via the ring-opening reaction of glycidol. The hPG film greatly reduced the adhesion of L929 cells and platelets as well as protein adsorption. The addition of alkenyl groups in the hPG layer allows the conjugation of biomolecules, such as peptides and biotin, and elicits specific biological interactions. Since the CVD deposition of PPX-OH could be applied to most types of materials, our approach makes it possible to decorate an antifouling hPG film on most types of materials. Our method could be applied to biosensors, diagnostics, and biomedical devices in the future.

The World Cafe has been used to develop business and organizational strategies, to enhance safety performance, to support executive education, to foster community development, and for a host of other specific applications. However, is the World Cafe superior to traditional strategy workshop techniques in terms of increases in participant knowledge and understanding? Up to now there has been no absolute no answer to this question. This study examines and compares how the World Cafe and Strategy Workshops influence the development of entrepreneurs in the writing of business plans and as a means to model learning behavior. This study also investigates which kinds of leadership styles (transactional leadership or transformational leadership) can simultaneously benefit learning performance. A quasi-experimental design is utilized which includes pre–post tests. 120 participants attending an entrepreneurial program held by the government are observed. The results indicate that the World Cafe strategy has a significantly higher positive effect on their strategic planning capability than with traditional Strategy Workshops. Second, the leadership style of the focus leader can significantly increase the entrepreneur's strategic planning capability. Finally, in the discussion of World Cafe, the effects of transactional leadership on the entrepreneur's strategic planning capability is found to be greater than the effects of transformational leadership.

The effects of Mg on the microstructural, optical, and electrical properties of sol-gel derived ZnO transparent semiconductor thin films and the photoelectrical properties of photodetectors based on MgxZn1&minus, xO (where x = 0 to 0.3) thin films with the metal-semiconductor-metal (MSM) configuration were investigated in this study. All the as-synthesized ZnO-based thin films had a single-phase wurtzite structure and showed high average transmittance of 91% in the visible wavelength region. The optical bandgap of MgxZn1&minus, xO thin films increased from 3.25 to 3.56 eV and the electrical resistivity of the films rose from 6.1 &times, 102 to 1.4 &times, 104 &Omega, &middot, cm with an increase in Mg content from x = 0 to x = 0.3. Compared with those of the pure ZnO thin film, the PL emission peaks of the MgZnO thin films showed an apparent blue-shift feature in the UV and visible regions. The photo-detection capability was investigated under visible, UVA, and UVC light illumination. Linear I-V characteristics were obtained in these ZnO-based photodetectors under dark and light illumination conditions, indicating an ohmic contact between the Au electrodes and ZnO-based thin films. It was found that the pure ZnO photodetector exhibited the best photoconductivity gain, percentage of sensitivity, and responsivity under UVA illumination. Under UVC illumination, the photoconductivity gain and percentage of sensitivity of the MgZnO photodetectors were better than those of the pure ZnO photodetector.

This study synthesized a TiO2/carbon nanotubes (CNTs) composite via the sol-gel method. The surface characteristics of the TiO2/CNTs composite were determined by X-ray diffraction, transmission electron microscopy, specific surface area analyser, ultraviolent (UV)-vis spectroscopy, X-ray photoelectron spectroscopy and Raman spectrometer. The photocatalytic activity ofthe TiO2/CNTs composite was evaluated by decolourizing C.I. Reactive Red 2 (RR2) under visible light irradiation. Furthermore, the effects of calcination temperature, pH, RR2 concentration, and the TiO2/CNTs composite dosage on RR2 decolourization were determined simultaneously. The optimal calcination temperature to generate TiO2 and the TiO2/CNTs composite was 673 K, as the percentage of anatase crystallization at this temperature was highest. The specific surface area of the TiO2/CNTs composite and TiO2 were 45 and 42 m2/g, respectively. The band gap of TiO2 and the TiO2/CNTs composite was 2.97 and 2.71 eV by UV-vis measurements, respectively. Experimental data indicate that the Ti-O-C bond formed in the TiO2/CNTs composite. The RR2 decolourization rates can be approximated by pseudo-first-order kinetics; moreover, only the TiO2/CNTs composite had photocatalytic activity under visible light irradiation. At pH 7, the RR2 decolourization rate constant of 0.5, 1 and 2 g/L TiO2/CNTs addition was 0.005, 0.0015, and 0.0047 min(-1), respectively. Decolourization rate increased as pH and the RR2 concentration decreased. The CNTs functioned as electron acceptors, promoting separation of photoinduced electron-hole pairs to retard their recombination; thus, photocatalytic activity of the TiO2/CNTs composite exceeded that of TiO2.

In this work, the sol-gel method is utilized to synthesize TiO2/powder-activated carbon (PAC) from TiCl4 and PAC. The TiO2/PAC system was used to decolorize C.I. Reactive Red 2 (RR2) under ultraviolet (UV) and visible light irradiation. The surface characteristics of TiO2 and TiO2/PAC were analyzed by X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, UV-vis spectroscopy, BET surface area analysis, and X-ray photoelectron spectroscopy (XPS). The effects of the C/Ti ratio, calcination temperature, photocatalyst dose, RR2 concentration, wavelength of light, and pH on the decolorization of RR2 by TiO2/PAC were evaluated. The optimal calcination temperature for forming TiO2 and TiO2/PAC was 400°C; moreover, the surface areas of TiO2 and TiO2/PAC were 42 and 108 m2/g, respectively. The sizes of the aggregates of TiO2 and TiO2/PAC particles were approximately 40 and 30 nm, respectively. Experimental results reveal that the percentage of anatase increased with the amoun...

The Taiwanese government has, based on the concept of the UK's Investors in People, and the ISO10015, drawn up the so-called Taiwan Training Quality System (TTQS), a training process including planning, designing, doing, and reviewing an outcome. This process is designed to ensure the reliability and validity of the system for the business training process. Also provided are methods for the implementation of self-assessment and improvement of the quality of the training system for enterprises and organisations. The aim of this study is to examine the criterion weights for The TTQS Excellence Model. With reference to the European Foundation for Quality Management (EFQM), our study divides the TTQS into two important parts: Enablers and Results. We utilise observations from 2053 enterprises which participated in the TTQS assessment in 2011. The TTQS score for each construct is turned into an EFQM Excellence Model to determine the weighted distribution for each construct. Our study compares the performance o...

The purpose of this study was to construct a professional competency framework for the marine leisure and tourism education in Taiwan. In order to meet the demands of tertiary institutions, marine leisure, marine tourism, water sports, for professionals in the marine leisure and tourism industry, this study considered it imperative to develop a framework of professional competency for marine leisure and tourism education. The Analytic Hierarchy Process (AHP) results showed that the academic experts emphasized basic knowledge in regard to marine leisure and tourism cultivation, performance competency, benefits of marine leisure and tourism activities, and marketing competency. The industry leaders focused on the safety management activities and competent operational abilities. The Decision Making Trial and Evaluation Laboratory (DEMATEL) results showed that the improvements in basic knowledge will contribute to the overall enhancement of professional competency.

Purpose: Quantitative breast density is known as a strong risk factor associated with the development of breast cancer.Measurement of breast density based on three-dimensional breast MRI may provide very useful information. One important step for quantitative analysis of breast density on MRI is the correction of field inhomogeneity to allow an accurate segmentation of the fibroglandular tissue (dense tissue). A new bias field correction method by combining the nonparametric nonuniformity normalization (N3) algorithm and fuzzy-C-means (FCM)-based inhomogeneity correction algorithm is developed in this work. Methods: The analysis is performed on non-fat-sat T1-weighted images acquired using a 1.5 T MRI scanner. A total of 60 breasts from 30 healthy volunteers was analyzed. N3 is known as a robust correction method, but it cannot correct a strong bias field on a large area. FCM-based algorithm can correct the bias field on a large area, but it may change the tissuecontrast and affect the segmentation quality. The proposed algorithm applies N3 first, followed by FCM, and then the generated bias field is smoothed using Gaussian kernal and B-spline surface fitting to minimize the problem of mistakenly changed tissuecontrast. The segmentation results based on the N 3 + FCM corrected images were compared to the N3 and FCM alone corrected images and another method, coherent local intensity clustering (CLIC), corrected images. The segmentation quality based on different correction methods were evaluated by a radiologist and ranked. Results: The authors demonstrated that the iterative N 3 + FCM correction method brightens the signal intensity of fatty tissues and that separates the histogram peaks between the fibroglandular and fatty tissues to allow an accurate segmentation between them. In the first reading session, the radiologist found ( N 3 + FCM > N 3 > FCM ) ranking in 17 breasts, ( N 3 + FCM > N 3 = FCM ) ranking in 7 breasts, ( N 3 + FCM = N 3 > FCM ) in 32 breasts, ( N 3 + FCM = N 3 = FCM ) in 2 breasts, and ( N 3 > N 3 + FCM > FCM ) in 2 breasts. The results of the second reading session were similar. The performance in each pairwise Wilcoxon signed-rank test is significant, showing N 3 + FCM superior to both N3 and FCM, and N3 superior to FCM. The performance of the new N 3 + FCM algorithm was comparable to that of CLIC, showing equivalent quality in 57/60 breasts. Conclusions: Choosing an appropriate bias field correction method is a very important preprocessing step to allow an accurate segmentation of fibroglandular tissues based on breast MRI for quantitative measurement of breast density. The proposed algorithm combining N 3 + FCM and CLIC both yield satisfactory results.

Nanoporous silica films were prepared through the templating of amphiphilic block copolymer, poly(styrene-2-vinyl pyridine) (PS-b-P2VP), and monodispersed colloidal silica nanoparticles. The experimental and theoretical studies suggested that the intermolecular hydrogen bonding existes between the colloidal silica nanoparticles and PS-b-P2VP. The effects of the loading ratio and P2VP chain length on the morphology and properties of the prepared nanoporous silica films were investigated. TEM and AFM studies showed that the uniform pore size could be achieved and the pore size increased with increasing porogen loading. The refractive index and dielectric constant of the prepared nanoporous films decreased with an increase in PS-b-P2VP loading. On the other hand, the porosity increased with an increasing PS-b-P2VP loading. This study demonstrated a methodology to control pore morphology and properties of the nanoporous silica films through the templating of PS-b-P2VP.

Structural properties of GaN epilayers on wet-etched protruding and recess-patterned sapphire substrates (PSSs) have been investigated in detail using high-resolution double-crystal X-ray diffraction (DCXRD) and etch-pit density methods. The DCXRD results reveal various dislocation configurations on both types of PSSs. The etch pits of GaN on the recess PSS exhibit a regular distribution, i.e. less etch pits or threading dislocation density (TDD) onto the recess area than those onto the sapphire mesas. On the contrary, an irregular distribution is observed for the etch pits of GaN on the protruding PSS. A higher crystal quality of the GaN epilayer grown onto the recess PSS can be achieved as compared with that onto the protruding PSS. These data reflect that the GaN epilayer on the recess PSS could be a better template for the second epitaxial lateral overgrowth (ELOG) of GaN. As a result, the GaN epilayers after the ELOG process display the TDDs of around ~10 6 cm -2 .

BACKGROUND: The self-assembly of amphiphilic copolymers has been demonstrated to be a powerful route towards supramolecular objects with novel architectures, functions and physical properties. In this study, the synthesis and morphology of amphiphilic linear polystyrene (PS)-block-poly(2-vinylpyridine) (P2VP) and heteroarm star PS-star-P2VP copolymers are studied. The dispersion of silver nanoparticles with the prepared PS-block-P2VP and PS-star-P2VP copolymers is also discussed. RESULTS: Amphiphilic copolymers with different P2VP chain lengths were successfully synthesized using atom transfer radical polymerization (ATRP). The copolymers prepared had low polydispersity indices. Various aggregate morphologies, including spheres, vesicles, rods, large compound micelles, two-dimensional ring-like and three-dimensional hollow structures, were formed by varying the hydrophilic coil length and the selective solvent content. Silver nanoparticles showed good dispersion behavior in both types of copolymers. CONCLUSION: Based on this study, it will be possible to prepare metal/copolymer nanocomposites by direct mixing. Further, the PS-block-P2VP and PS-star-P2VP copolymers prepared can be used in the preparation of nanoporous films as templates and nanoparticles as nanoreactors. They can also be applied in terms of oil recovery, paints and cosmetics formulations, as well as in pharmaceutical and medical applications as rheological agents. Copyright © 2008 Society of Chemical Industry

Nanoporous silica films were prepared through the templating of amphiphilic block copolymer, poly(styrene-2-vinyl pyridine) (PS-b-P2VP), and colloidal silica nanoparticles. The experimental and theoretical studies suggested that the intermolecular hydrogen bonding was existed between the colloidal silica nanoparticles and PS-b-P2VP. The miscible hybrid and the narrow thermal decomposition of the PS-b-P2VP led to nanopores in the prepared films from the results of TGA, AFM, and TEM. The effects of the loading ratio and P2VP chain length on the morphology and properties of the prepared nanoporous silica films were investigated. The TEM and AFM studies showed that the uniform pore morphology with pore size 10-15nm was prepared from a modest porogen loading level for the optimum intermolecular hydrogen bonding. The refractive index and dielectric constant of the prepared nanoporous films decreased with an increase in PS-b-P2VP loading. On the other hand, the porosity increased with an increasing PS-b-P2VP loading. This study demonstrated a methodology to control pore morphology and properties of the nanoporous silica films through the templating of PS-b-P2VP.

The preparation of PMMA–clay nanocomposites was investigated by using sodium dodecylbenzenesulfonate (SDS) and potassium peroxodisulfate (KPS) as a surfactant and chain initiator for an in situ emulsion polymerization reaction, respectively. The as-prepared nanocomposites were then characterized by Fourier transformation infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXRD) patterns and transmission electron microscopy (TEM). It should be noted that the nanocomposite coating containing 1 wt% of clay loading was found to exhibit an observable enhanced corrosion protection on cold-rolled steel (CRS) electrode at higher operational temperature of 50 °C, which was even better than that of uncoated and electrode-coated with PMMA alone at room temperature of 30 °C based on the electrochemical parameter evaluations (e.g., Ecorr, Rp, Icorr, Rcorr and impedance). In this work, all electrochemical measurements were performed at a double-wall jacketed cell, covered with a glass plate, through which water was circulated from a thermostat to maintain a constant operational temperature of 30, 40 and 50 ± 0.5 °C. Moreover, a series of electrochemical parameters shown in Tafel, Nyquist and Bode plots were all used to evaluate PCN coatings at three different operational temperatures in 5 wt% aqueous NaCl electrolyte. The molecular barrier properties at three different operational temperatures of PMMA and PCN membranes were investigated by gas permeability analyzer (GPA) and vapor permeability analyzer (VPA). Effect of material composition on the molecular weight and optical properties of neat PMMA and PCN materials, in the form of solution and membrane, were also studied by gel permeation chromatography (GPC) and UV–vis transmission spectra.

Quantitative breast density is known as a strong risk factor associated with the development of breast cancer. Measurement of breast density based on three-dimensional breast MRI may provide very useful information. One important step for quantitative analysis of breast density on MRI is the correction of field inhomogeneity to allow an accurate segmentation of the fibroglandular tissue (dense tissue). A new bias field correction method by combining the nonparametric nonuniformity normalization (N3) algorithm and fuzzy-C-means (FCM)-based inhomogeneity correction algorithm is developed in this work.The analysis is performed on non-fat-sat T1-weighted images acquired using a 1.5 T MRI scanner. A total of 60 breasts from 30 healthy volunteers was analyzed. N3 is known as a robust correction method, but it cannot correct a strong bias field on a large area. FCM-based algorithm can correct the bias field on a large area, but it may change the tissue contrast and affect the segmentation quality. The proposed algorithm applies N3 first, followed by FCM, and then the generated bias field is smoothed using Gaussian kernal and B-spline surface fitting to minimize the problem of mistakenly changed tissue contrast. The segmentation results based on the N3+FCM corrected images were compared to the N3 and FCM alone corrected images and another method, coherent local intensity clustering (CLIC), corrected images. The segmentation quality based on different correction methods were evaluated by a radiologist and ranked.The authors demonstrated that the iterative N3+FCM correction method brightens the signal intensity of fatty tissues and that separates the histogram peaks between the fibroglandular and fatty tissues to allow an accurate segmentation between them. In the first reading session, the radiologist found (N3+FCMN3FCM) ranking in 17 breasts, (N3+FCMN3 = FCM) ranking in 7 breasts, (N3+FCM = N3FCM) in 32 breasts, (N3+FCM = N3 = FCM) in 2 breasts, and (N3N3+FCMFCM) in 2 breasts. The results of the second reading session were similar. The performance in each pairwise Wilcoxon signed-rank test is significant, showing N3+FCM superior to both N3 and FCM, and N3 superior to FCM. The performance of the new N3+FCM algorithm was comparable to that of CLIC, showing equivalent quality in 57/60 breasts.Choosing an appropriate bias field correction method is a very important preprocessing step to allow an accurate segmentation of fibroglandular tissues based on breast MRI for quantitative measurement of breast density. The proposed algorithm combining N3+FCM and CLIC both yield satisfactory results.

In this paper, we propose a novel unsupervised algorithm for the segmentation of salient regions in color images. There are two phases in this algorithm. In the first phase, we use nonparametric density estimation to extract dominant colors in an image, which are then used for the quantization of the image. The label map of the quantized image forms initial regions of segmentation. In the second phase, a region merging approach is performed. It merges the initial regions using a novel region attraction rule to form salient regions. Experimental results show that the proposed method achieves excellent segmentation performance for most of our test images. In addition, the computation is very efficient.