Generation of Continuously Variable-mode Orbital Angular Momentum Beams

Orbital angular momentum (OAM) beam emitters with compact structure and high performance are highly desirable for wireless communication and radar technology. Here, we propose a compact emitter that only consists of a ring resonator and a feed line. Continuously-variable-mode OAM beams are generated by adjusting the wavelength and transmission path. The basic design principle and specific evaluation index are discussed. Both the simulated and experimental results demonstrate that the proposed emitter obtains the capacity of generating variable-modes. This approach opens a way for designing novel OAM beam emitter with desired properties

Event-Based Blackboard Architecture for Multi-Agent Systems

Developing large multi-agent systems is a complex task involving the processes of the requirement, architecture, design and implementation of these systems. In particular, the architectural design is critical to cope with the increasing size and complexity of these systems. The multi-agent system that accesses a central repository is typically based on the Blackboard architectural pattern. However, the control strategies of the agents are inherently complex. In this paper, we present an eventbased control strategy to manage the access of central repository by multi-agents. In this approach, the Blackboard pattern is composed with the Implicit Invocation pattern to separate the control policies from the control component so that the architecture is ease of evolution, reuses and changes

Dynamic Frequency Allocation in SLICE Considering both BER and Distance

Proposed in this paper is a dynamic resource-aware routing and frequency slots allocation scheme with consideration of both BER requirement and distance adaptive modulation (RA-BERR-DA) for spectrum-sliced elastic optical path networks (SLICE).Numerical simulations are conducted to analysis network performance such as blocking rate and the number of used frequency slots. The results demonstrate that this scheme is able to decrease traffic blocking and improve resource utilization in dynamic spectrum assignment. DOI: http://dx.doi.org/10.11591/telkomnika.v10i7.144

A Feature Extraction Method Using Auditory Nerve Response for Collapsing Coal-Gangue Recognition

To intelligentize the top-coal caving’s process, many data-driven coal-gangue recognition techniques have been proposed recently. However, practical applications of these techniques are hindered by coal mine underground’s high background noise and complex environment. Considering that workers distinguish coal and gangue by hearing the impact sounds on the hydraulic support, we proposed a novel feature extraction method based on an auditory nerve (AN) response model simulating the human auditory system. Firstly, vibration signals were measured by an acceleration sensor mounted on the back of the hydraulic support’s tail beam, and then they were converted into acoustic pressure signals. Secondly, an AN response model of different characteristic frequencies was applied to process these signals, whose output constituted the auditory spectrum for feature extraction. Meanwhile, a feature selection method integrated with variance was used to reduce redundant information of the original features. Finally, a support vector machine was employed as the classifier model in this work. The proposed method was tested and evaluated on experimental datasets collected from the Tashan Coal Mine in China. In addition, its recognition accuracy was compared with other coal-gangue recognition methods based on commonly used features. The results show that our proposed method can reach a superior recognition accuracy of 99.23% and presents better generalization ability

Thermally tunable slot-coupled dielectric resonator antenna

A thermally tunable slot-coupled dielectric resonator antenna (DRA) has been designed and prepared by placing a thermosensitive ceramic resonator onto the slot. Typical magnetic resonance occurs in the resonator, which is closely related to its dielectric constant. Because the dielectric constant of the ceramic resonator decreases as the temperature increases, the resonance frequency of the proposed DRA increases as the temperature increases. The simulated results are in good agreement with the measured ones, which confirms the thermally tunable behavior. This approach provides a way for designing the frequency tunable antennas

Investigation of the Tribological Behavior and Microstructure of Plasma-Cladded Fe–Cr–Mo–Ni–B Coating

In this study, an Fe–Cr–Mo–Ni–B coating was prepared using plasma cladding on Cr5 steel substrate. The microstructure, phase evolution and tribological performance of the Fe–Cr–Mo–Ni–B coating were investigated. The microstructure is mainly composed of Mo2FeB2, Fe2B, α-Fe, γ-Fe and MoB. The process of phase evolution in the coating was observed in situ by HT-CLSM. The Mo2FeB2 phase with good thermodynamic stability can exist in the high-temperature liquid phase. It also has a phenomenon of connection and merging and turns into different morphology during the plasma cladding process. The hardness value of coating was much higher than the base metal, and the hardness value of Mo2FeB2 (785.5 HV) was higher than the eutectic matrix (693.2 HV). The wear mechanisms of the cladding under dry sliding were primarily caused by adhesive wear, accompanying slight oxidation wear. The Mo2FeB2 phase has an important effect on the wear resistance property

Controllable Fabrication of Molecularly Imprinted Microspheres with Nanoporous and Multilayered Structure for Dialysate Regeneration

Adsorption of urea from dialysate is essential for wearable artificial kidneys (WRK). Molecularly imprinted microspheres with nanoporous and multilayered structures are prepared based on liquid–liquid phase separation (LLPS), which can selectively adsorb urea. In addition, we combine the microspheres with a designed polydimethylsiloxane (PDMS) chip to propose an efficient urea adsorption platform. In this work, we propose a formulation of LLPS including Tripropylene glycol diacrylate (TPGDA), ethanol, and acrylic acid (30% v/v), to prepare urea molecularly imprinted microspheres in a simple and highly controllable method. These microspheres have urea molecular imprinting sites on the surface and inside, allowing selective adsorption of urea and preservation of other essential constituents. Previous static studies on urea adsorption have not considered the combination between urea adsorbent and WRK. Therefore, we design the platform embedded with urea molecular imprinted microspheres, which can disturb the fluid motion and improve the efficiency of urea adsorption. These advantages enable the urea absorption platform to be highly promising for dialysate regeneration in WRK

Risk assessment and dissemination mechanism of antibiotic resistance genes in compost

In recent years, the excessive of antibiotics in livestock and poultry husbandry, stemming from extensive industry experience, has resulted in the accumulation of residual antibiotics and antibiotic resistance genes (ARGs) in livestock manure. Composting, as a crucial approach for the utilization of manure resources, has the potential to reduce the levels of antibiotics and ARGs in manure, although complete elimination is challenging. Previous studies have primarily focused on the diversity and abundance of ARGs in compost or have solely examined the correlation between ARGs and their carriers, potentially leading to a misjudgment of the actual risk associated with ARGs in compost. To address this gap, this study investigated the transfer potential of ARGs in compost and their co-occurrence with opportunistic pathogenic bacteria by extensively analyzing metagenomic sequencing data of compost worldwide. The results demonstrated that the potential risk of ARGs in compost was significantly lower than in manure, suggesting that composting effectively reduces the risk of ARGs. Further analysis showed that the microbes shifted their life history strategy in manure and compost due to antibiotic pressure and formed metabolic interactions dominated by antibiotic-resistant microbes, increasing ARG dissemination frequency. Therefore, husbandry practice without antibiotic addition was recommended to control ARG evolution, dissemination, and abatement both at the source and throughout processing

Experimental Demonstration of Neural Network-based Soft Demapper for Long-haul Optical Transmission

Experimental validation for a proposed neural network-based soft demapper is demonstrated. A reach increase of 9.8% and a demapping complexity reduction of 28.6% for PM-64QAM with 11× 450Gbps DWDM is achieved over the conventional demapper.</p