System Featuring Research Articles

A wideband circularly polarized four port microstrip MIMO antenna with high gain and enhanced isolation for 5G millimeter frequency applications

Abstract In this article, a MIMO antenna system featuring wide bandwidth, high gain, and circular polarization for 5G communication networks is presented. The proposed antenna enables high data rates, enhanced signal reliability, and improved performance in dynamic and challenging 5G environments. Wide bandwidth ensures compatibility with various 5G frequency bands, while circular polarization allows for better signal propagation and reception, particularly in non-line-of-sight scenarios. In that regard, the present endeavor exhibits an enhanced bandwidth 4-port circularly polarized MIMO antenna to encounter polarization mismatch along with high data rates. The presented MIMO antenna comprises four identical patches strategically positioned in orthogonal orientations in such a way as to provide the circular polarization direction. Meanwhile, the bandwidth is extended by inserting straightforward defected ground structure (DGS) and L slots. The MIMO antenna anticipated in this work offers an impedance bandwidth covering from 24 GHz to 28.5 GHz and an axial ratio bandwidth of 62% within the overall band. It demonstrates excellent performance with a high peak gain of approximately 14.84 dB. Additionally, it exhibits strong isolation of more than 20dB among the closely packed antennas, ensuring reliable communication and minimizing interference. The combination of these features in a MIMO antenna system is crucial for meeting the demanding requirements of 5G communication, including increased data capacity, low latency, and reliable connectivity. The simulated and measured outcomes exhibit robust concurrence, signifying a high level of accuracy. Consequently, the suggested MIMO antenna appears well-suited for encompassing the 5G bands designated for deployment in the USA (27.50–28.35 GHz) and Europe (24.25 - 27.5 GHz).

The dynamics of capillary flow in an open-channel system featuring trigger valves.

Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels. We also show that a series of open-channel trigger valves can be placed alongside or opposite a main channel resulting in a layered capillary flow. We developed a closed form model for the dynamics of the flow at trigger valves based on the concept of average friction length and successfully validated the model against experiments. For the main channel, we discuss layered flow behavior in the light of the Taylor-Aris dispersion theory and in the channel turns by considering Dean theory of mixing. This work has potential applications in autonomous microfluidics systems for biosensing, at-home or point-of-care sample preparation devices, hydrogel patterning for 3D cell culture and organ-on-a-chip models.

Emergency provider preference for powered intraosseous devices and satisfaction with features improving safety, reliability, and ease-of-use

ABSTRACT Background Powered intraosseous (IO) systems are valuable devices for emergent situations, with limited data on user preferences. A simulation/survey-based study was conducted among emergency medical service (EMS) providers to evaluate attitudes toward general powered IO system features to measure preferences/satisfaction for the most-commonly used and a novel powered IO system (with a passive safety needle, battery life indicator, and snap-securement/dressing). Research Design and Methods Forty-two EMS providers completed a simulated activity using both powered IO systems and a 30-item questionnaire, including multiple choice, free-text, ranking, and Likert-like questions. Ranking scores were reported using a scale of 0 (least important/satisfactory) to 100 (most important/satisfactory). Statistical significances were evaluated via Wilcoxon signed-rank sum test. Results Providers indicated driver performance (mean score ± SD; 77.8 ± 27.5) and IO needle safety mechanism (63.1 ± 27.9) as the most important features. Participants reported significantly higher (p < 0.001) satisfaction with the novel IO system overall, and its needle safety, battery life indicator, securement/dressing, and ease-of-use. Powered driver performance satisfaction was similar and favorable for the novel (88.1 ± 18.2) and traditional (87.1 ± 15.3) systems. Conclusions These findings highlight the value of clinician/user input and demonstrate EMS providers are more satisfied with a powered IO system featuring design elements intended to enhance safety and ease-of-use.

Physician preferences associated with powered intraosseous access systems: Safety features, reliability, and ease of use.

ObjectiveThis study evaluated physician preferences and values related to the most commonly used (traditional) powered intraosseous (IO) system and a novel powered IO system featuring a passive safety needle, battery life indicator, and snap‐securement/skin attachment.MethodsEmergency physicians participated in an IO simulation using both the traditional and novel IO systems. Participants completed a 27‐item postsimulation questionnaire to state their preferences toward each IO system and values related to the novel IO system features using a multiple choice, 11‐point value ranking scale (0 = no value, 10 = extremely valuable) and free‐text answer questions.ResultsAmong the 22 study participants, 90.9% (95% confidence interval [CI]: 70.8%, 98.9%) preferred the novel IO system; top reasons for this preference were the novel IO system's passive safety needle and snap‐securement/skin attachment. Participants who preferred the traditional IO system (9.1%) noted its ease of use and familiarity. Many physicians preferred the novel IO system's needle (81.8%; 95% CI: 59.7%, 94.8%), powered driver (77.3%; 95% CI: 54.6%, 92.2%), and snap‐securement/skin attachment (100%; 95% CI: 84.6%, 100%) compared with the traditional IO system. Safety and ease of use were the most common preference explanations. Of the participants, 100% provided a value score ≥7 for the novel IO system's passive safety needle (mean score, 9.45), whereas fewer participants (59.1%) gave a value score ≥7 for the multilight battery life indicator (mean score, 6.68).ConclusionThis study demonstrates that emergency physicians prefer and value a novel IO system with features that enhance safety and ease of use. These results provide insight into important factors related to IO systems for emergency physicians.

Evaluation of a Rural Healthcare System Featuring Medical and Premedical Students: The Essentia Health Summer Research Intern Program

Background: Training medical and premedical students in clinical research is challenging with the demands of medical education. Students pursue research opportunities in specialty practice to acquire knowledge and gain experience in the clinical setting. Pairing clinical observation with mentored research informs the value of evidence-based medicine and prepares students for a career in medicine and science. However, programs that offer both research training and clinical observership are rare, particularly in rural areas. &#x0D; Hypothesis: Early exposure to sub-specialty practice in rural areas is important to recruit and train the next generation of physicians to serve this population. &#x0D; Methods: This report provides a description of the Essentia Health Summer Research Internship Program, a pilot program with the University of Minnesota Medical School aimed to provide mentored clinical research training and clinical observership for medical and premedical students. The program provided an experiential model of clinical patient interaction, problem solving, and access to research that is integrated into clinical experiences as students learn the value of evidence-based medicine. &#x0D; Results: Six medical and four premedical students have participated in the internship within the programs first two years. Student-completed weekly journals and surveys reveal enthusiasm for various research and clinical components of the program. Program highlights include the acquisition of research and clinical knowledge through mentorship and research lectures, and observerships throughout the Heart and Vascular Center. &#x0D; Conclusion: The program aims to provide underrepresented rural students training in research methodology through mentorship and observership within specialty practice.

Community Health Centers: a Key Partner to Achieve Medicaid Expansion.

Medicaid expansion is an important feature of the "Affordable Care Act" and also is proposed as a component of some incremental plans for universal healthcare coverage. We describe (1) obstacles encountered with Medicaid coverage, (2) their potential resolution by federally qualified community health centers (CHCs), (3) the current status and limitations of CHCs, and (4) a proposed mega CHC model which could help assure access to care under Medicaid coverage expansion. Proposed development of the mega CHC model involves a three-component system featuring (1) satellite neighborhood outreach clinics, with team care directed by primary care nurse practitioners, (2) a hub central CHC which would closely correspond to the logistics and administration of current CHCs, and (3) a teaching hospital facilitating subspecialty care for CHC patients, with high-quality and cost-effectiveness. We believe that this new model, designated as a mega CHC, will demonstrate that CHCs can achieve their potential as a key partner to insure care under Medicaid expansion.

Developing a Model-based Drinking Water Decision Support System Featuring Remote Sensing and Fast Learning Techniques.

Timely adjustment of operating strategies in drinking water treatment in response to water quality variations of both natural and anthropogenic causes is a grand technical challenge. One essential approach is to develop and apply integrated sensing, monitoring, and modeling technologies to provide early warning messages to plant operators. This paper presents a thorough literature review of the technical methods, followed by the development of a model-based decision support system (DSS). The DSS aims to aid water treatment operation via source water impact analysis. This model-based DSS featuring remote sensing and fast learning techniques can be easily applied by end-users and provide a visual depiction of spatiotemporal variation in water quality parameters of interest in source water. The system is able to forecast the trend of water quality one day into the future at a specific location and to nowcast water quality at water intake, thus helping the assessment of water quality in finished water against treatment objectives. The model-based DSS was assessed in a case study at a water treatment plant in Las Vegas, United States.

Collaborative control of a dual electro-hydraulic regenerative brake system for a rear-wheel-drive electric vehicle

Within the field of electric vehicles, the cooperative control of a dual electro-hydraulic regenerative brake system using the foot brake pedal as the sole input of driver brake requests is a challenging control problem, especially when the electro-hydraulic brake system features on/off solenoid valves which are widely used in the automotive industry. This type of hydraulic actuator is hard to use to perform a fine brake pressure regulation. Thus, this paper focuses on the implementation of a novel controller design for a dual electro-hydraulic regenerative brake system featuring on/off solenoid valves which track an “ideal” brake force distribution. As an improvement to a standard brake force distribution, it can provide the reach of the maximum braking adherence and can improve the energy recovery of a rear-wheel-drive electric vehicle. This improvement in energy recovery is possible with the complete substitution of the rear hydraulic brake force with a regenerative brake force until the reach of the electric powertrain constraints. It is done by performing a proper brake pressure fine regulation through the proposed variable structure control of the on/off solenoid valves provided by the hydraulic platform of the vehicle stability system. Through road tests, the tracking feasibility of the proposed brake force distribution with the mechatronic system developed is validated.

Shock Formation for 2D Quasilinear Wave Systems Featuring Multiple Speeds: Blowup for the Fastest Wave, with Non-trivial Interactions up to the Singularity

We prove a stable shock formation result for a large class of systems of quasilinear wave equations in two spatial dimensions. We give a precise description of the dynamics all the way up to the singularity. Our main theorem applies to systems of two wave equations featuring two distinct wave speeds and various quasilinear and semilinear nonlinearities, while the solutions under study are (non-symmetric) perturbations of simple outgoing plane symmetric waves. The two waves are allowed to interact all the way up to the singularity. Our approach is robust and could be used to prove shock formation results for other related systems with many unknowns and multiple speeds, in various solution regimes, and in higher spatial dimensions. However, a fundamental aspect of our framework is that it applies only to solutions in which the "fastest wave" forms a shock while the remaining solution variables do not. Our approach is based on an extended version of the geometric vectorfield method developed by D. Christodoulou in his study of shock formation for scalar wave equations as well as the framework developed in our recent joint work with J. Luk, in which we proved a shock formation result for a quasilinear wave-transport system featuring a single wave operator. A key new difficulty that we encounter is that the geometric vectorfields that we use to commute the equations are, by necessity, adapted to the wave operator of the (shock-forming) fast wave and therefore exhibit very poor commutation properties with the slow wave operator, much worse than their commutation properties with a transport operator. To overcome this difficulty, we rely on a first-order reformulation of the slow wave equation, which, though somewhat limiting in the precision it affords, allows us to avoid uncontrollable commutator terms.

Working fluid selection and electrical performance optimisation of a domestic solar-ORC combined heat and power system for year-round operation in the UK

In this paper, we examine the electrical power-generation potential of a domestic-scale solar combined heating and power (S-CHP) system featuring an organic Rankine cycle (ORC) engine and a 15-m2 non-concentrated solar-thermal collector array. The system is simulated with a range of organic working fluids and its performance is optimised for operation in the UK climate. The findings are applicable to similar geographical locations with significant cloud coverage, a low solar resource and limited installation areas. A key feature of the system’s design is the implementation of fixed fluid flow-rates during operation in order to avoid penalties in the performance of components suffered at part-load. Steady operation under varying solar irradiance conditions is provided by way of a working-fluid buffer vessel at the evaporator outlet, which is maintained at the evaporation temperature and pressure of the ORC. By incorporating a two-stage solar collector/evaporator configuration, a maximum net annual electrical work output of 1070kWhyr−1 (continuous average power of 122W) and a solar-to-electrical efficiency of 6.3% is reported with HFC-245ca as the working fluid at an optimal evaporation saturation temperature of 126°C (corresponding to an evaporation pressure of 16.2bar). This is equivalent to ∼32% of the electricity demand of a typical/average UK home, and represents an improvement of more than 50% over a recent effort by the same authors based on an earlier S-CHP system configuration and HFC-245fa as the working fluid [1], thus highlighting the gains possible when using optimal system configurations and fluids and suggesting that significant further improvements may be possible. A performance and simple cost comparison with stand-alone, side-by-side PV and solar-thermal heating systems is presented.

22.8 Multi-Functional Microelectrode Array System Featuring 59,760 Electrodes, 2048 Electrophysiology Channels, Impedance and Neurotransmitter Measurement Units.

Various CMOS-based micro-electrode arrays (MEAs) have been developed in recent years for extracellular electrophysiological recording/stimulation of electrogenic cells [1-5]. Mostly two approaches have been used: (i) the activepixel approach (APS) [2-4], which features simultaneous readout of all electrodes, however, at the expense of a comparably high noise level, and (ii) the switchmatrix (SM) approach, which yields better noise performance, whereas only a subset of electrodes (e.g.,1024) is simultaneously read out [5]. All systems feature, at most, voltage recording and/or voltage/current stimulation functionalities.

Multilayered silica-biopolymer nanocapsules with a hydrophobic core and a hydrophilic tunable shell thickness.

Stable, biocompatible, multifunctional and multicompartment nanocarriers are much needed in the field of nanomedicine. Here, we report a simple, novel strategy to design an engineered nanocarrier system featuring an oil-core/hybrid polymer/silica-shell. Silica shells with a tunable thickness were grown in situ, directly around a highly mono-disperse and stable oil-in-water emulsion system, stabilized by a double bio-functional polyelectrolyte heparin/chitosan layer. Such silica showed a complete degradation in a physiological medium (SBF) in a time frame of three days. Moreover, the outer silica shell was coated with polyethyleneglycol (PEG) in order to confer antifouling properties to the final nanocapsule. The outer silica layer combined its properties (it is an optimal bio-interface for bio-conjugations and for the embedding of hydrophilic drugs in the porous structure) with the capability to stabilize the oil core for the confinement of high payloads of lipophilic tracers (e.g., CdSe quantum dots, Nile Red) and drugs. In addition, polymer layers--besides conferring stability to the emulsion while building the silica shell--can be independently exploited if suitably functionalized, as demonstrated by conjugating chitosan with fluorescein isothiocyanate. Such numerous features in a single nanocarrier system make it very intriguing as a multifunctional platform for smart diagnosis and therapy.

Global Resource Scheduler in a Mobile Communications System Featuring Heterogeneous Architecture

This article addresses the dynamic resource allocation problem (power and frequency resources) for the downlink of a multicell, multiservice mobile communication system with heterogeneous architecture, deployed into a urban environment, using OFDM (Orthogonal Frequency Division Multiplexing) at the physical level. The proposed optimization model aims to fairly satisfy the user service requirements, yielding effective resource usage, and using the Signal-to-Noise plus Interference Ratio (SINR) as a quality metric. Due that the model is integer, non-linear and mixed, and it is complex to directly obtain a solution from such a model, we use an approximate algorithm that decouples the problem solution space, and an iterative improvement strategy. The scheduler allocates resources aiming to reach the required SINR for each user, using the system global vision. Since it is not always possible to accomplish this, the scheduler takes advantage of the elasticity of some of the offered services, and incorporates a slack variable, in order to always guarantee a feasible model and obtain high value performance.&#61472;

A High-Sensitivity Radar System Featuring Low Weight and Power Consumption

In this article, a lightweight, low-power radar system for vibration monitoring has been presented. Based on a theoretical analysis of the competition scenario, an optimized system concept has been developed. The radar front end is able to sequentially evaluate the in-phase and quadrature component of the received signal with only a single hybrid coupler and power detector, reducing the overall weight to 5 g including the power-supply cable. A low duty cycle of 1% allowed the power to average 1.5 mW. As the minimum required sensitivity was limited to 0.5-mm oscillation amplitude, the most challenging parts in this student competition were, in our opinion, the tight power and weight optimizations. As the competition required only vibration detection butno ranging, a minimalistic system concept optimized for this application was proposed. The system features a free-running VCO sourced directly from the power supply without any further stabilization. For ranging applications, temperature changes as well as supply and tuning voltage variations at the VCO could have a severe impact on the system's accuracy. However, for pure vibration detection of a well-defined target, this is not a problem. Further improvements could be achieved when designing a customized 24-GHz oscillator, optimized for high efficiency [9] and fast turn-on time. In addition, the necessary number of measurements per second could be further investigated. Currently, with ten measurements per second, there is a convenient safety margin against false detections; however, fewer measurements would directly reduce the duty cycle and thus the average power consumption of the system.

The Performance of Systems Featuring Dynamic Decode-and-Forward and Network Coding

We constructed a single-relay-station cooperative communications system, featuring integration between the dynamic decode-and-forward (DDF) protocol and network coding (NC) to examine the outage probabilities in the Rayleigh, Rician, and Nakagami fading channels. In addition, the diversity-multiplexing tradeoff of the system was analyzed to examine improvements for system performance through integrating these two technologies. Through simulations and analyses, we discovered that the systems featuring NC had lower outage probability and greater diversity gain, and consequently, greater system reliability compared to the ordinary system featuring only the DDF protocol. However, because we added a final phase for the transmission of network coded signals, the system showed lower multiplexing gain compared to the system featuring only the DDF. Users should adopt this system based on their needs. For example, in situations that have higher requirements for reliability and lower requirements for multiplexing gain, users can adopt a DDF-NC cooperative communications system.

Torque Control of a New Haptic Master for Surgical Robot System Featuring Electrorheological Fluid Based Spherical Joint

Torque Control of a New Haptic Master for Surgical Robot System Featuring Electrorheological Fluid Based Spherical Joint

Effect of Friction on Dynamics of Gear System Featuring Confluence Transmission

In order to investigate the effect of friction on gear system featuring confluence transmission, a non-linear dynamic model of three-gear system having two gear pairs was built. The influence of gear systems dynamic characteristics caused by changing of friction coefcient was researched. With the changing of friction coefcient, left-right gear pairs show dynamic behavior with coexist of same periodic motion, coexist of different periodic motion and chaos. With the increase of friction coefcient, the jump phenomenon of amplitude occurred, the impact of gear system became larger.

Size-dependent nucleation kinetics at nonplanar nanowire growth interfaces

In nanowire growth, kinetic processes at the growth interface can play an important role in governing wire compositions, morphologies, and growth rates. Molecular-dynamics simulations have been undertaken to probe such processes in a system featuring a solid-liquid interface shape characterized by a facet bounded by rough orientations. Simulated growth rates display a dependence on nanowire diameter consistent with a size-dependent barrier for facet nucleation. A theory for the interface mobility is developed, establishing a source for size-dependent growth rates that is an intrinsic feature of systems possessing growth interfaces with faceted and rough orientations.

Determination of monochloroacetic acid using a flow injection system featuring a flow through ion-selective electrode and an ion-exchange column for the minimization of interference by chloride.

An automated flow injection system for on-line monitoring of monochloroacetic acid (MCAA) in industrial processes for the production of zwitterionic surfactants (betaines) is developed, which can treat samples with chloride ion concentration up to 1 M. The system features an ion-exchange column for the separation of MCAA from the interferents in the complex sample. The sample is injected at low pH values so that interfering anions, mainly chloride, are retained in the ion exchange column. Detection is performed using specially constructed all-solid-state tubular flow-through ion selective electrodes sensitive to monochloroacetate. Selectivity data of the constructed electrodes are given, while their pH working range is 4.0–11.0 and their lifetime is greater than 30 days through a range between 10 −4–10 −1 M. Once applied to the treatment of real samples, the system developed can detect MCAA in the range between 5·10 −3–10 −1 M, with a maximum deviation of 5% when compared to standard photometric methods of analysis. The short time used in each determination (30 s) in addition to its simplicity, leads to an improvement of the techniques of analysis used until now.

ASR and TTS telecommunications applications in Japan

This paper first describes recent trends of ASR and TTS telecommunications applications in Japan. ASR applications focus on public services such as operator automation, operator assistance, voice-activated information retrieval, and voice dialing. Major TTS applications include information service by voice and e-mail reading. The usage of ASR and TTS functions is expected to dramatically increase in the near future with the penetration of handy and mobile telephone terminals; hot topics are text broadcasting and digital communication. Secondly this paper describes NTT's experimental interactive system featuring (1) highly accurate speaker independent and large vocabulary speech recognition based on context-dependent accurate acoustic phoneme HMM models trained with speech data from more than 10,000 speakers collected over telephone network, (2) high quality text-to-speech synthesis that generates speech by concatenating triphone-context-dependent waveform segments, (3) software-based configuration that requires no special hardware except a PC equipped with a sound board and a voice modem, and (4) easy and rapid prototyping which enables the developer to build a system by writing some types of service scenarios.