Open AccessArticle
Incremental Design of Perishable Goods Marketsthrough Multi-Agent Simulations
Appl. Sci. 2017, 7(12), 1300; doi:10.3390/app7121300 (registering DOI) -
Abstract
In current markets of perishable goods such as fish and vegetables, sellers are typically in a weak bargaining position, since perishable products cannot be stored for long without losing their value. To avoid the risk of spoiling products, sellers have few alternatives other
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In current markets of perishable goods such as fish and vegetables, sellers are typically in a weak bargaining position, since perishable products cannot be stored for long without losing their value. To avoid the risk of spoiling products, sellers have few alternatives other than selling their goods at the prices offered by buyers in the markets. The market mechanism needs to be reformed in order to resolve unfairness between sellers and buyers. Double auction markets, which collect bids from both sides of the trades and match them, allow sellers to participate proactively in the price-making process. However, in perishable goods markets, sellers have an incentive to discount their bid gradually for fear of spoiling unsold goods. Buyers can take advantage of sellers’ discounted bids to increase their profit by strategic bidding. To solve the problem, we incrementally improve an online double auction mechanism for perishable goods markets, which promotes buyers’ truthful bidding by penalizing their failed bids without harming their individual rationality. We evaluate traders’ behavior under several market conditions using multi-agent simulations and show that the developed mechanism achieves fair resource allocation among traders. Full article
Open AccessArticle
A Psychoacoustic-Based Multiple Audio Object Coding Approach via Intra-Object Sparsity
Appl. Sci. 2017, 7(12), 1301; doi:10.3390/app7121301 (registering DOI) -
Abstract
Rendering spatial sound scenes via audio objects has become popular in recent years, since it can provide more flexibility for different auditory scenarios, such as 3D movies, spatial audio communication and virtual classrooms. To facilitate high-quality bitrate-efficient distribution for spatial audio objects, an
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Rendering spatial sound scenes via audio objects has become popular in recent years, since it can provide more flexibility for different auditory scenarios, such as 3D movies, spatial audio communication and virtual classrooms. To facilitate high-quality bitrate-efficient distribution for spatial audio objects, an encoding scheme based on intra-object sparsity (approximate k-sparsity of the audio object itself) is proposed in this paper. The statistical analysis is presented to validate the notion that the audio object has a stronger sparseness in the Modified Discrete Cosine Transform (MDCT) domain than in the Short Time Fourier Transform (STFT) domain. By exploiting intra-object sparsity in the MDCT domain, multiple simultaneously occurring audio objects are compressed into a mono downmix signal with side information. To ensure a balanced perception quality of audio objects, a Psychoacoustic-based time-frequency instants sorting algorithm and an energy equalized Number of Preserved Time-Frequency Bins (NPTF) allocation strategy are proposed, which are employed in the underlying compression framework. The downmix signal can be further encoded via Scalar Quantized Vector Huffman Coding (SQVH) technique at a desirable bitrate, and the side information is transmitted in a lossless manner. Both objective and subjective evaluations show that the proposed encoding scheme outperforms the Sparsity Analysis (SPA) approach and Spatial Audio Object Coding (SAOC) in cases where eight objects were jointly encoded. Full article
Open AccessMeeting Report
Report of the 2017 IEEE Cyber Science and Technology Congress
Appl. Sci. 2017, 7(12), 1299; doi:10.3390/app7121299 -
Abstract
The modern digitized world has led to the emergence of a new paradigm on global information networks and infrastructures known as Cyberspace and the studies of Cybernetics, which bring seamless integration of physical, social and mental spaces. Cyberspace is becoming an integral part
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The modern digitized world has led to the emergence of a new paradigm on global information networks and infrastructures known as Cyberspace and the studies of Cybernetics, which bring seamless integration of physical, social and mental spaces. Cyberspace is becoming an integral part of our daily life from learning and entertainment to business and cultural activities. As expected, this whole concept of Cybernetics brings new challenges that need to be tackled. The 2017 IEEE Cyber Science and Technology Congress (CyberSciTech 2017) provided a forum for researchers to report their research findings and exchange ideas. The congress took place in Orlando, Florida, USA during 6–10 November 2017. Not counting poster papers, the congress accepted over fifty papers that are divided into nine sessions. In this report, we provide an overview of the research contributions of the papers in CyberSciTech 2017. Full article
Open AccessFeature PaperReview
Highly Doped Phosphate Glass Fibers for Compact Lasers and Amplifiers: A Review
Appl. Sci. 2017, 7(12), 1295; doi:10.3390/app7121295 -
Abstract
In recent years, the exploitation of compact laser sources and amplifiers in fiber form has found extensive applications in industrial and scientific fields. The fiber format offers compactness, high beam quality through single-mode regime and excellent heat dissipation, thus leading to high laser
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In recent years, the exploitation of compact laser sources and amplifiers in fiber form has found extensive applications in industrial and scientific fields. The fiber format offers compactness, high beam quality through single-mode regime and excellent heat dissipation, thus leading to high laser reliability and long-term stability. The realization of devices based on this technology requires an active medium with high optical gain over a short length to increase efficiency while mitigating nonlinear optical effects. Multicomponent phosphate glasses meet these requirements thanks to the high solubility of rare-earth ions in their glass matrix, alongside with high emission cross-sections, chemical stability and high optical damage threshold. In this paper, we review recent advances in the field thanks to the combination of highly-doped phosphate glasses and innovative fiber drawing techniques. We also present the main performance achievements and outlook both in continuous wave (CW) and pulsed mode regimes. Full article
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Open AccessArticle
Wearable Vibration Based Computer Interaction and Communication System for Deaf
Appl. Sci. 2017, 7(12), 1296; doi:10.3390/app7121296 -
Abstract
In individuals with impaired hearing, determining the direction of sound is a significant problem. The direction of sound was determined in this study, which allowed hearing impaired individuals to perceive where sounds originated. This study also determined whether something was being spoken loudly
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In individuals with impaired hearing, determining the direction of sound is a significant problem. The direction of sound was determined in this study, which allowed hearing impaired individuals to perceive where sounds originated. This study also determined whether something was being spoken loudly near the hearing impaired individual. In this manner, it was intended that they should be able to recognize panic conditions more quickly. The developed wearable system has four microphone inlets, two vibration motor outlets, and four Light Emitting Diode (LED) outlets. The vibration of motors placed on the right and left fingertips permits the indication of the direction of sound through specific vibration frequencies. This study applies the ReliefF feature selection method to evaluate every feature in comparison to other features and determine which features are more effective in the classification phase. This study primarily selects the best feature extraction and classification methods. Then, the prototype device has been tested using these selected methods on themselves. ReliefF feature selection methods are used in the studies; the success of K nearest neighborhood (Knn) classification had a 93% success rate and classification with Support Vector Machine (SVM) had a 94% success rate. At close range, SVM and two of the best feature methods were used and returned a 98% success rate. When testing our wearable devices on users in real time, we used a classification technique to detect the direction and our wearable devices responded in 0.68 s; this saves power in comparison to traditional direction detection methods. Meanwhile, if there was an echo in an indoor environment, the success rate increased; the echo canceller was disabled in environments without an echo to save power. We also compared our system with the localization algorithm based on the microphone array; the wearable device that we developed had a high success rate and it produced faster results at lower cost than other methods. This study provides a new idea for the benefit of deaf individuals that is preferable to a computer environment. Full article
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Open AccessFeature PaperReview
Imaging Flow Velocimetry with Laser Mie Scattering
Appl. Sci. 2017, 7(12), 1298; doi:10.3390/app7121298 -
Abstract
Imaging flow velocity measurements are essential for the investigation of unsteady complex flow phenomena, e.g., in turbomachines, injectors and combustors. The direct optical measurement on fluid molecules is possible with laser Rayleigh scattering and the Doppler effect. However, the small scattering cross-section results
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Imaging flow velocity measurements are essential for the investigation of unsteady complex flow phenomena, e.g., in turbomachines, injectors and combustors. The direct optical measurement on fluid molecules is possible with laser Rayleigh scattering and the Doppler effect. However, the small scattering cross-section results in a low signal to noise ratio, which hinders time-resolved measurements of the flow field. For this reason, the signal to noise ratio is increased by using laser Mie scattering on micrometer-sized particles that follow the flow with negligible slip. Finally, the ongoing development of powerful lasers and fast, sensitive cameras has boosted the performance of several imaging methods for flow velocimetry. The article describes the different flow measurement principles, as well as the fundamental physical measurement limits. Furthermore, the evolution to an imaging technique is outlined for each measurement principle by reviewing recent advances and applications. As a result, the progress, the challenges and the perspectives for high-speed imaging flow velocimetry are considered. Full article
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Open AccessArticle
An Unsupervised Method of Change Detection in Multi-Temporal PolSAR Data Using a Test Statistic and an Improved K&I Algorithm
Appl. Sci. 2017, 7(12), 1297; doi:10.3390/app7121297 -
Abstract
In recent years, multi-temporal imagery from spaceborne sensors has provided a fast and practical means for surveying and assessing changes in terrain surfaces. Owing to the all-weather imaging capability, polarimetric synthetic aperture radar (PolSAR) has become a key tool for change detection. Change
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In recent years, multi-temporal imagery from spaceborne sensors has provided a fast and practical means for surveying and assessing changes in terrain surfaces. Owing to the all-weather imaging capability, polarimetric synthetic aperture radar (PolSAR) has become a key tool for change detection. Change detection methods include both unsupervised and supervised methods. Supervised change detection, which needs some human intervention, is generally ineffective and impractical. Due to this limitation, unsupervised methods are widely used in change detection. The traditional unsupervised methods only use a part of the polarization information, and the required thresholding algorithms are independent of the multi-temporal data, which results in the change detection map being ineffective and inaccurate. To solve these problems, a novel method of change detection using a test statistic based on the likelihood ratio test and the improved Kittler and Illingworth (K&I) minimum-error thresholding algorithm is introduced in this paper. The test statistic is used to generate the comparison image (CI) of the multi-temporal PolSAR images, and improved K&I using a generalized Gaussian model simulates the distribution of the CI. As a result of these advantages, we can obtain the change detection map using an optimum threshold. The efficiency of the proposed method is demonstrated by the use of multi-temporal PolSAR images acquired by RADARSAT-2 over Wuhan, China. The experimental results show that the proposed method is effective and highly accurate. Full article
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Open AccessFeature PaperReview
Flexible and Organic Neural Interfaces: A Review
Appl. Sci. 2017, 7(12), 1292; doi:10.3390/app7121292 -
Abstract
Neural interfaces are a fundamental tool to interact with neurons and to study neural networks by transducing cellular signals into electronics signals and vice versa. State-of-the-art technologies allow both in vivo and in vitro recording of neural activity. However, they are mainly made
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Neural interfaces are a fundamental tool to interact with neurons and to study neural networks by transducing cellular signals into electronics signals and vice versa. State-of-the-art technologies allow both in vivo and in vitro recording of neural activity. However, they are mainly made of stiff inorganic materials that can limit the long-term stability of the implant due to infection and/or glial scars formation. In the last decade, organic electronics is digging its way in the field of bioelectronics and researchers started to develop neural interfaces based on organic semiconductors, creating more flexible and conformable neural interfaces that can be intrinsically biocompatible. In this manuscript, we are going to review the latest achievements in flexible and organic neural interfaces for the recording of neuronal activity. Full article
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Open AccessArticle
Robust Visual Localization with Dynamic Uncertainty Management in Omnidirectional SLAM
Appl. Sci. 2017, 7(12), 1294; doi:10.3390/app7121294 -
Abstract
This work presents a robust visual localization technique based on an omnidirectional monocular sensor for mobile robotics applications. We intend to overcome the non-linearities and instabilities that the camera projection systems typically introduce, which are especially relevant in catadioptric sensors. In this paper,
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This work presents a robust visual localization technique based on an omnidirectional monocular sensor for mobile robotics applications. We intend to overcome the non-linearities and instabilities that the camera projection systems typically introduce, which are especially relevant in catadioptric sensors. In this paper, we come up with several contributions. First, a novel strategy for the uncertainty management is developed, which accounts for a realistic visual localization technique, since it dynamically encodes the instantaneous variations and drifts on the uncertainty, by defining an information metric of the system. Secondly, an epipolar constraint adaption to the omnidirectional geometry reference is devised. Thirdly, Bayesian considerations are also implemented, in order to produce a final global metric for a consistent feature matching between images. The resulting outcomes are supported by real data experiments performed with publicly-available datasets, in order to assess the suitability of the approach and to confirm the reliability of the main contributions. Besides localization results, real visual SLAM (Simultaneous Localization and Mapping) comparison experiments with acknowledged methods are also presented, by using a public dataset and benchmark framework. Full article
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Open AccessArticle
Vibrotactile Display of Flight Attitude with Combination of Multiple Coding Parameters
Appl. Sci. 2017, 7(12), 1291; doi:10.3390/app7121291 -
Abstract
Vibrotactile (vibratory tactile) displays have been reported as effective in enhancing awareness of flight attitude for pilots and releasing other heavily loaded sensory channels. Although some work has been done on vibrotactile coding of flight attitude, there is lack of a systematic investigation
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Vibrotactile (vibratory tactile) displays have been reported as effective in enhancing awareness of flight attitude for pilots and releasing other heavily loaded sensory channels. Although some work has been done on vibrotactile coding of flight attitude, there is lack of a systematic investigation into coding methods with combination of multiple coding parameters. In this paper, seven coding methods with seven combinations of multiple coding parameters (location, rhythm, intensity, and mode) were systematically studied to cue flight attitude for pilots with vibrotactile vest. We conducted two psychophysical experiments in a static environment in which the attitude information in the form of vibrotactile feedback are presented randomly, and quantitatively evaluated the effectiveness of the vest according to the users’ recognition accuracy, reaction time and information transfer rate. The results show that vibrotactile vest is effective to cue attitude information. The preferred coding method with combinations of location, rhythm and mode allowed users to perform with lowest reaction time and highest recognition accuracy and yield about 255 bits/min of information transfer rate. Overall, the presented work provides valuable insights and guidance for the design of vibrotactile aids for the pilots. Full article
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Open AccessArticle
Stabilize and Flatten Multi-Wavelength Erbium-Doped Fiber Laser through Accurate Hybrid Dual-Ring-Configuration Control
Appl. Sci. 2017, 7(12), 1290; doi:10.3390/app7121290 -
Abstract
In order to enhance the practicality of multi-wavelength erbium-doped fiber lasers (MWEDFLs), a novel hybrid dual-ring configuration is proposed in this article, which can flatten the outputs through an optical nonlinear-polarization-rotation-based ring cavity and stabilize the shifts of power and central wavelength of
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In order to enhance the practicality of multi-wavelength erbium-doped fiber lasers (MWEDFLs), a novel hybrid dual-ring configuration is proposed in this article, which can flatten the outputs through an optical nonlinear-polarization-rotation-based ring cavity and stabilize the shifts of power and central wavelength of oscillations through an electrical fuzzy-control-based feedback. The experiment results show that, our scheme achieves more than 10 stable oscillations with the dramatic improvements in flatness and working stability. Under dual-ring configuration, the output intensity of MWEDFL reaches ~−7.5 dBm with the flatness of ±0.42 dB. And the in-stabilities in terms of power and central wavelength are respectively constrained ±0.182 dBm and ±0.029 nm within 10-h continuous operation. Full article
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Open AccessFeature PaperArticle
Audio Time Stretching Using Fuzzy Classification of Spectral Bins
Appl. Sci. 2017, 7(12), 1293; doi:10.3390/app7121293 -
Abstract
A novel method for audio time stretching has been developed. In time stretching, the audio signal’s duration is expanded, whereas its frequency content remains unchanged. The proposed time stretching method employs the new concept of fuzzy classification of time-frequency points, or bins, in
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A novel method for audio time stretching has been developed. In time stretching, the audio signal’s duration is expanded, whereas its frequency content remains unchanged. The proposed time stretching method employs the new concept of fuzzy classification of time-frequency points, or bins, in the spectrogram of the signal. Each time-frequency bin is assigned, using a continuous membership function, to three signal classes: tonalness, noisiness, and transientness. The method does not require the signal to be explicitly decomposed into different components, but instead, the computing of phase propagation, which is required for time stretching, is handled differently in each time-frequency point according to the fuzzy membership values. The new method is compared with three previous time-stretching methods by means of a listening test. The test results show that the proposed method yields slightly better sound quality for large stretching factors as compared to a state-of-the-art algorithm, and practically the same quality as a commercial algorithm. The sound quality of all tested methods is dependent on the audio signal type. According to this study, the proposed method performs well on music signals consisting of mixed tonal, noisy, and transient components, such as singing, techno music, and a jazz recording containing vocals. It performs less well on music containing only noisy and transient sounds, such as a drum solo. The proposed method is applicable to the high-quality time stretching of a wide variety of music signals. Full article
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Open AccessFeature PaperArticle
Automatic Transcription of Polyphonic Vocal Music
Appl. Sci. 2017, 7(12), 1285; doi:10.3390/app7121285 -
Abstract
This paper presents a method for automatic music transcription applied to audio recordings of a cappella performances with multiple singers. We propose a system for multi-pitch detection and voice assignment that integrates an acoustic and a music language model. The acoustic model performs
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This paper presents a method for automatic music transcription applied to audio recordings of a cappella performances with multiple singers. We propose a system for multi-pitch detection and voice assignment that integrates an acoustic and a music language model. The acoustic model performs spectrogram decomposition, extending probabilistic latent component analysis (PLCA) using a six-dimensional dictionary with pre-extracted log-spectral templates. The music language model performs voice separation and assignment using hidden Markov models that apply musicological assumptions. By integrating the two models, the system is able to detect multiple concurrent pitches in polyphonic vocal music and assign each detected pitch to a specific voice type such as soprano, alto, tenor or bass (SATB). We compare our system against multiple baselines, achieving state-of-the-art results for both multi-pitch detection and voice assignment on a dataset of Bach chorales and another of barbershop quartets. We also present an additional evaluation of our system using varied pitch tolerance levels to investigate its performance at 20-cent pitch resolution. Full article
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Open AccessArticle
Improving Performance of Cold-Chain Insulated Container with Phase Change Material: An Experimental Investigation
Appl. Sci. 2017, 7(12), 1288; doi:10.3390/app7121288 -
Abstract
The cold-chain transportation is an important means to ensure the drug and food safety. An cold-chain insulated container incorporating with Phase Change Material (PCM) has been developed for a temperature-controlled transportation in the range of 2~8 °C. The container configuration and different preconditioning
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The cold-chain transportation is an important means to ensure the drug and food safety. An cold-chain insulated container incorporating with Phase Change Material (PCM) has been developed for a temperature-controlled transportation in the range of 2~8 °C. The container configuration and different preconditioning methods have been determined to realize a 72-h transportation under extremely high, extremely low, and alternating temperature conditions. The experimental results showed that the temperature-controlled time was extended from 1 h to more than 80 h and the internal temperature maintained at 4~5 °C by using a PCM with a melting/freezing point of 5 °C, while the container presented a subcooling effect in a range of −1~2 °C when using water as PCM. The experimental values of the temperature-controlled time agreed well with the theoretical values. Full article
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Open AccessArticle
A Novel Fractional Fourier Transform-Based ASK-OFDM System for Underwater Acoustic Communications
Appl. Sci. 2017, 7(12), 1286; doi:10.3390/app7121286 -
Abstract
A key research area in wireless transmission is underwater communications. It has a vital role in applications such as underwater sensor networks (UWSNs) and disaster detection. The underwater channel is very unique as compared to other alternatives of transmission channels. It is characterized
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A key research area in wireless transmission is underwater communications. It has a vital role in applications such as underwater sensor networks (UWSNs) and disaster detection. The underwater channel is very unique as compared to other alternatives of transmission channels. It is characterized by path loss, multipath fading, Doppler spread and ambient noise. Thus, the bit error rate (BER) is increased to a large extent when compared to its counterpart of cellular communications. Acoustic signals are the current best solution for underwater communications. The use of electromagnetic or optical waves obviously entails a much higher data rate. However, they suffer from high attenuation, absorption or scattering. This paper proposes a novel fractional fast Fourier transform (FrFT)—orthogonal frequency division multiplexing (FrFT-OFDM) system for underwater acoustic (UWA) communication—which employs the amplitude shift keying (ASK) modulation technique (FrFT-ASK-OFDM). Specifically, ASK achieves a better bandwidth efficiency as compared to other commonly used modulation techniques, such as quadrature amplitude modulation (QAM) and phase shift keying (PSK). In particular, the system proposed in this article can achieve a very promising BER performance, and can reach higher data rates when compared to other systems proposed in the literature. The BER performance of the proposed system is evaluated numerically, and is compared to the corresponding M-ary QAM system in the UWA channel for the same channel conditions. Moreover, the performance of the proposed system is compared to the conventional fast Fourier transform (FFT)-OFDM (FFT-OFDM) system in the absence and presence of the effect of carrier frequency offset (CFO). Numerical results show that the proposed system outperforms the conventional FFT-based systems for UWA channels, even in channels dominated by CFO. Moreover, the spectral efficiency and data rate of the proposed system are approximately double the values of the corresponding conventional OFDM systems for the same parameters. Full article
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Open AccessArticle
Functional Elastic Knits Made of Bamboo Charcoal and Quick-Dry Yarns: Manufacturing Techniques and Property Evaluations
Appl. Sci. 2017, 7(12), 1287; doi:10.3390/app7121287 -
Abstract
Conventional sportswear fabrics are functional textiles that can mitigate the impaired muscles caused by exercises for the wearers, but they can also cause discomfort and skin allergy. This study proposes combining two yarns to form functional composite yarns, by using a twisting or
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Conventional sportswear fabrics are functional textiles that can mitigate the impaired muscles caused by exercises for the wearers, but they can also cause discomfort and skin allergy. This study proposes combining two yarns to form functional composite yarns, by using a twisting or wrapping process. Moreover, a different twist number is used in order to adjust the performance of functional composite yarns. A crochet machine is used to make the functional composite yarns into functional elastic knits that are suitable for use in sportswear. The test results show that, in comparison to the non-processed yarns, using the twisted or wrapped yarns can considerably decrease the water vapor transmission rate of functional elastic knits by 38%, while also improving their far infrared emissivity by 13%, water absorption rate by 39%, and air permeability by 136%. In particular, the functional elastic knits that are made of B-wrapped yarns (bamboo charcoal- wrapped yarns), composed of 20 twists per inch, have the optimal diverse functions. Full article
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Open AccessArticle
A Three-Axis Magnetic Field Microsensor Fabricated Utilizing a CMOS Process
Appl. Sci. 2017, 7(12), 1289; doi:10.3390/app7121289 -
Abstract
This study develops a three-axis magnetic field (MF) microsensor manufactured by a complementary metal oxide semiconductor (CMOS) process. The MF microsensor contains a ring emitter, four bases, and eight collectors. Sentaurus TCAD was used to simulate the microsensor characterization. The STI (shallow trench
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This study develops a three-axis magnetic field (MF) microsensor manufactured by a complementary metal oxide semiconductor (CMOS) process. The MF microsensor contains a ring emitter, four bases, and eight collectors. Sentaurus TCAD was used to simulate the microsensor characterization. The STI (shallow trench isolation) oxide in the process was used to limit the current direction and reduce leakage current. The microsensor produces a voltage difference once it senses a magnetic field. An amplifier circuitry magnifies voltage difference into a voltage output. Experiments reveals that the MF microsensor has a sensitivity of 1.45 V/T along the x-axis and a sensitivity of 1.37 V/T along the y-axis. Full article
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Open AccessArticle
Simultaneous Extraction, Enrichment and Removal of Dyes from Aqueous Solutions Using a Magnetic Aqueous Micellar Two-Phase System
Appl. Sci. 2017, 7(12), 1257; doi:10.3390/app7121257 -
Abstract
The magnetic aqueous micellar two-phase system (MAMTPS) has the advantages combined of magnetic solid phase extraction (MSPE) and aqueous micellar two-phase system (AMTPS). Thus, MAMTPS based on Fe3O4 magnetic nanoparticles (MNPs) and a nonionic surfactant Triton X-114 (TX-114) was developed
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The magnetic aqueous micellar two-phase system (MAMTPS) has the advantages combined of magnetic solid phase extraction (MSPE) and aqueous micellar two-phase system (AMTPS). Thus, MAMTPS based on Fe3O4 magnetic nanoparticles (MNPs) and a nonionic surfactant Triton X-114 (TX-114) was developed for the extraction, enrichment and removal of three dyes (Congo red, methyl blue, and methyl violet) from aqueous solutions in this study. The MNPs Fe3O4@NH2 was screened as the optimal MNPs benefiting the extraction. Then, the influencing factors of MNPs amount, TX-114 concentration, vibration time, and extraction temperature were investigated in detail. The results showed that the extraction efficiencies of three dyes almost reached 100% using MAMTPS under the optimal conditions; MAMTPS had higher extraction ability than the individual MSPE or AMTPS. Thus, MAMTPS had the advantages of simple operation, high extraction ability, easy recycling of MNPs, and short phase-separation time, which showspotential for use in the extraction and analysis of contaminants from water samples. Full article
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Open AccessArticle
The Effects of Musical Experience and Hearing Loss on Solving an Audio-Based Gaming Task
Appl. Sci. 2017, 7(12), 1278; doi:10.3390/app7121278 -
Abstract
We conducted an experiment using a purposefully designed audio-based game called the Music Puzzle with Japanese university students with different levels of hearing acuity and experience with music in order to determine the effects of these factors on solving such games. A group
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We conducted an experiment using a purposefully designed audio-based game called the Music Puzzle with Japanese university students with different levels of hearing acuity and experience with music in order to determine the effects of these factors on solving such games. A group of hearing-impaired students (n = 12) was compared with two hearing control groups with the additional characteristic of having high (n = 12) or low (n = 12) engagement in musical activities. The game was played with three sound sets or modes; speech, music, and a mix of the two. The results showed that people with hearing loss had longer processing times for sounds when playing the game. Solving the game task in the speech mode was found particularly difficult for the group with hearing loss, and while they found the game difficult in general, they expressed a fondness for the game and a preference for music. Participants with less musical experience showed difficulties in playing the game with musical material. We were able to explain the impacts of hearing acuity and musical experience; furthermore, we can promote this kind of tool as a viable way to train hearing by focused listening to sound, particularly with music. Full article
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Open AccessFeature PaperArticle
Optimization of Virtual Loudspeakers for Spatial Room Acoustics Reproduction with Headphones
Appl. Sci. 2017, 7(12), 1282; doi:10.3390/app7121282 -
Abstract
The use of headphones in reproducing spatial sound is becoming more and more popular. For instance, virtual reality applications often use head-tracking to keep the binaurally reproduced auditory environment stable and to improve externalization. Here, we study one spatial sound reproduction method over
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The use of headphones in reproducing spatial sound is becoming more and more popular. For instance, virtual reality applications often use head-tracking to keep the binaurally reproduced auditory environment stable and to improve externalization. Here, we study one spatial sound reproduction method over headphones, in particular the positioning of the virtual loudspeakers. The paper presents an algorithm that optimizes the positioning of virtual reproduction loudspeakers to reduce the computational cost in head-tracked real-time rendering. The listening test results suggest that listeners could discriminate the optimized loudspeaker arrays for renderings that reproduced a relatively simple acoustic conditions, but optimized array was not significantly different from equally spaced array for a reproduction of a more complex case. Moreover, the optimization seems to change the perceived openness and timbre, according to the verbal feedback of the test subjects. Full article
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