Core Switching Research Articles

A RMSCA algorithm for space division multiplexing elastic optical networks with core switching

Space division multiplexing elastic optical networks (SDM-EONs) have attracted much attention due to the advantages of high capacity, flexibility, and spectrum utilization. Space division multiplexing technology enhances the capacity of a single fiber link by using multi-core fiber (MCF). With the support of MCFs, SDM-EONs will become an important form of future optical transmission networks.In order to reduce the blocking rate of the network, this paper proposes a routing, modulation format, spectrum and core allocation (RMSCA) algorithm based on the maximum number of available cores with core switching. The algorithm selects the spectrum block with the most available cores in the entire path for spectrum allocation by using core switching. We perform simulations on two networks, NSF-Net and UBN24, and compare them with the spectrum allocation algorithm with core switching (FF-ISC-RMSCA), which uses first-time adaptation, and the spectrum allocation algorithm with maximum number of cores available (N-ISC-RMSCA), which does not perform core switching. Simulation results show that the proposed algorithm significantly reduces the bandwidth blocking rate and has high spectrum utilization.

5G Network with Hexagonal SDN Control for Highly Secure Multimedia Communication

The 5G communication network is a promising technology that offers user-centric connectivity to customers, enabling quick, high-capacity, and latency-free access to many applications. Software Defined Networking Controller (SDNC) is an emerging technology that is used for increasing the security and maintaining the dynamic nature of mobile devices in latency and energy-assured 5G wireless communication. Different SDN topology open flow controllers are used in the literature for increasing the throughput and security of the network but they possess some drawbacks such as frequent location update (LU) overhead, high latency, and high energy consumption. This paper proposes a hexagonal software defined network (H-SDN) controller to overcome these challenges. The proposed H-SDN topology is used to preserve Intermediate Message Layer (IML) location during multimedia data transmission. A Core Switch (CS) updates an IML's location within clusters of cells, as long as it remains within the cluster. However, in the proposed method, there will be a location update on the server if the IML departs the cluster. Experiment results show that the proposed method can increase security, which in turn increases throughput, while reduces the location update costs, energy consumption, and transmission latency.

Strategy to Increase Market Share Current Account Saving Account (CASA) Through Optimizing the Development of Electronic Banking in Indonesia

The basis of this research is motivated by the phenomenon that occurs where banking services in Indonesia have still known for a very long time and require a struggle to make a transaction. A network that is often problematic, strict regulations and the length of the account creation process are some examples of problems related to banking services in Indonesia. This study aims to find out how the development of electronic banking at Bank BJB, the Market Share Current Account Savings Account at Bank BJB, what obstacles are faced in the development of electronic banking at Bank BJB, and what strategies are carried out to increase CASA market share through the optimization of electronic banking development. The research method used is qualitative by interviewing resource persons from within the company, policymakers, and practitioners in the banking sector. The results obtained show that Bank BJB has carried out digital service transformation specifically in 2021. The company has made several developments in terms of core banking, switching, and networking. CASA's market share has not reached the expected target. Several strategies to increase Bank BJB's CASA market share through electronic banking optimization include the development of a user-friendly Mobile application. Focus on developing an intuitive and easy-to-use mobile app.

Deep-reinforcement-learning-based RMSCA for space division multiplexing networks with multi-core fibers [Invited Tutorial

The escalating demands for network capacities catalyze the adoption of space division multiplexing (SDM) technologies. With continuous advances in multi-core fiber (MCF) fabrication, MCF-based SDM networks are positioned as a viable and promising solution to achieve higher transmission capacities in multi-dimensional optical networks. However, with the extensive network resources offered by MCF-based SDM networks comes the challenge of traditional routing, modulation, spectrum, and core allocation (RMSCA) methods to achieve appropriate performance. This paper proposes an RMSCA approach based on deep reinforcement learning (DRL) for MCF-based elastic optical networks (MCF-EONs). Within the solution, a novel state representation with essential network information and a fragmentation-aware reward function were designed to direct the agent in learning effective RMSCA policies. Additionally, we adopted a proximal policy optimization algorithm featuring an action mask to enhance the sampling efficiency of the DRL agent and speed up the training process. The performance of the proposed algorithm was evaluated with two different network topologies with varying traffic loads and fibers with different numbers of cores. The results confirmed that the proposed algorithm outperforms the heuristics and the state-of-the-art DRL-based RMSCA algorithm in reducing the service blocking probability by around 83% and 51%, respectively. Moreover, the proposed algorithm can be applied to networks with and without core switching capability and has an inference complexity compatible with real-world deployment requirements.

Ion core switching during photodissociation dynamics via the Rydberg states of XeAr

The heterodimer, XeAr, is a classic example of a weakly bound van der Waals molecule, which has a variety of accessible bound excited states that exhibit complex interactions. In this study, XeAr has been investigated in the 77,500–81,500 cm−1 region using a combination of Resonance Enhanced Multi-Photon Ionization (REMPI) spectroscopy and Velocity Map Imaging (VMI). By monitoring REMPI and photodissociative product channels across the spectrum, several novel excited states, product channels, excited state symmetries and lifetimes, as well as highly localized perturbations were observed and characterized, including the first VMI study of Ar* dissociating from XeAr Rydberg states accessed by two-photon excitation. In this work we have analyzed 38 vibronic bands representing nine different electronic transitions, and we provide new assignments for two 0+←0+ electronic transitions dissociating to the Xe* 5d [3/2]02 (ca. 80,323 cm−1) and Xe* 5d [7/2]03 (ca. 80,970 cm−1) limits. Several new predissociation product channels were identified at the two- and three-photon levels, including production of Xe* 5p[5/2]3, Xe* 6s'[1/2]o1, Xe* 6p[1/2]1, Ar* 4p[1/2]0, Ar* 4p'[3/2]1, Ar* 4p'[1/2]1, and Ar* 4p[5/2]3. Using the multidimensional analysis offered by VMI, we explore interesting photophysics whereby a resonant state that is reached after absorbing two photons can predissociate to yield Xe*, but which also can absorb a 3rd photon, yielding super-excited Ar*Xe that predissociates to Ar* limits. The ground state dissociation energy for XeAr was determined to be D0 = 114.4 ± 2.7 cm−1, in excellent agreement with previous measurements.

Soft Switched High Step-Up Multiport Converter With Single Magnetic Core and Auxiliary Switch for Renewable Energy Applications

Soft Switched High Step-Up Multiport Converter With Single Magnetic Core and Auxiliary Switch for Renewable Energy Applications

Empirical Comparison of Energy Efficiency Between 3-Tier and High-Speed 3-Tier Network Topologies

The high levels of energy use for cloud computing affect carbon emissions and climate change. This research thoroughly compares the energy utilisation of conventional and high-speed three-tier data centres (DCs). The green cloud simulator (GCS) was used to compare network configurations and energy-saving algorithms for each cloud's energy consumption in 10 trials. The power saver schedule algorithm used the least server energy, while the green and RR schedule algorithms used more. Despite the testing of several energy conservation approaches, core switch and aggregate switch energy usage remained unchanged. Although the high-speed three-tier DC architecture used more energy than the standard design, this is a key difference between the two network topologies. The authors discuss the power saver schedule algorithm's benefits for server energy utilisation. This study shows how three-tier DC architecture can save money by reducing core switch and aggregation switch energy use. These evaluations should include the make span coefficient, and future research should focus on DC transform energy-saving techniques.

Multi-core fiber rotated optical switch

We propose an optical switch technique that enables unused optical fiber to be activated without on-site work for the purpose of efficiently supporting future optical communication services. The proposed technique performs fiber switching by rotating a multi-core fiber (MCF) by a single motor. The MCF is inserted into a cylindrical ferrule to avoid fiber damage, when rotated against another fiber. The two ferrules are inserted into a sleeve so that their endfaces oppose each other, and the cores are linked across the gap. We optimize the sleeve size not only to reduce the friction between the ferrule and the sleeve, which can create excessive motor power consumption, but also to reduce the loss. We fabricate a 2.5-mm diameter cylindrical ferrule attached a homogeneous MCF with a hexagonal seven-core structure and experimentally evaluate the loss characteristics during rotation of the MCF for core switching. We clarify the potential of the resulting optical switch.

Wideband 120-GHz CMOS I/Q Transmitter With Suppressed IMRR and LOFT for Wireless Short-Range High-Speed 6G IoT Applications

In this study, a wideband 120-GHz I/Q transmitter with suppressed image rejection ratio (IMRR) and LO feedthrough (LOFT) is presented using 40-nm complementary metal oxide semiconductor technology. For the up-conversion mixer, an NMOS/PMOS pair with resistive feedback is used during the transconductance stage to increase the input bandwidth with gain boosting, and a novel switching core without LO-RF coupling is used to suppress the LOFT effect. For the quadrature injection locked tripler, an I/Q calibration circuit is inserted to minimize the I/Q mismatch; accordingly, the measured IMRR is greatly improved. The peak conversion gain of the proposed transmitter was 10.8 dB, and the 3-dB gain bandwidth was 20 GHz. The measured IMD2 and IMD3 were above 40 dBc. Moreover, the IMRR was measured as 43.1 dBc, applying I/Q calibration. The measured LOFT was 33.7 dBc. The data rate of the proposed transmitter was measured up to 20 Gbps and at a distance of 5 cm. Subsequently, the error vector magnitudes were 13.4 dB for QPSK and -19.1 dB for 16-QAM modulation. It is expected that such wireless high-speed communication can be applied to wireless short range high-speed 6G IoT applications.

A Coupled-Inductor-Based Nonisolated DC-DC Converter With High Step-Down and Wide Input Voltage

In the data center applications, the bus converter not only needs to achieve high step-down gain but also can keep stable output for data back-up when the bus voltage drops dramatically due to fault. Thus, a coupled-inductor-based nonisolated DC-DC converter with high step-down and wide input range is proposed in this paper. The proposed converter utilizes the coupled inductor to obtain the high step-down capability and the series-capacitor to achieve zero voltage switching and zero magnetizing currents, which can help reduce switching loss and core loss. Thanks to the feature of the voltage gain, lower conduction loss at low input voltage and wider input voltage can be ensured. The feasibility of the converter is verified by detailed theoretical analysis and a prototype with the 36∼60V input voltage, 3.3V output voltage, and the 1∼10A output current. The efficiency of the prototype can be maintained above 90% under all conditions, and the peak efficiency is 95.8%.

Optimum Firing Angles Control for Switched Reluctance Motor Based on IPSO at Steady State

To avoid the control error caused by the inaccuracy of the analytical model as used in traditional method, in this paper, a novel model free scheme based on intelligent optimum algorithm - improved particle swarm optimization (IPSO) to search the optimum firing angles of switched reluctance motor (SRM) drives online is proposed. The optimum firing angles can be searched by the proposed scheme online with fast convergence speed and high probability according to the criterion of minimum the phase current when the SRM operated at a constant speed and load torque in single pulse model. For cumbersome and complicated process to calculate or measure flux or inductance to decide firing angles value is not needed, only the RMS phase current needs to be measured as guidance, the proposed optimum method is easy to implement. It is also not affected by system parameters variation and the dynamic performance is not influenced. The impact of saturation of core, back-EMF, fringing effect, iron loss and power switch loss has been considered in the proposed method, but the traditional methods cannot. Experimental and simulation results are carried out to verify the effectiveness and high performance of the proposed optimum firing angles control algorithm.

Irreversible switching of vortex core in Pac-man nanodisks induced by rotating magnetic fields

Vortex has attracted great attention recently due to its potential applications in information storage, nano-oscillators and logic devices. The control of vortex polarity is key to the devices based on vortex. In this paper, an irreversible vortex core (VC) switching in Pac-man disks has been investigated by micromagnetic simulations. The switching process is closely related to the evolution of energy densities and there is a sharp peak in the local exchange energy density when VC switching occurs. Irreversible switching of VC can be realized due to the weak interaction between reversed vortex and rotating magnetic field. In the process of VC reversal, the positive and negative magnetization regions of the gyrofield are separated. Moreover, the switching time of VC decreases monotonously with frequency under rotating magnetic fields. When one direction of the rotating magnetic field is turned off, the difference in switching time is attributed to the different motion behaviors of vortex. This work benefits the potential storage applications in vortex-based spintronic devices.

Research and Simulation of OCDM Switch Layer Based on 2D WDM-Optical Code Switching Structure

Optical Communication is widely used in military and civilian backbone network communication, but due to the limitation of “electronic bottleneck”, the ability of network nodes to process information and optical layer data transmission capacity is seriously mismatched, which directly causes optical cross connectors in optical nodes. The number of ports carried has skyrocketed. In order to improve the processing speed of network nodes, this paper studies the four-layer multi-granularity switching system of optical fiber, wavelength band, wavelength, and optical code, and finally builds a complete OCDMA system through simulation software, simulates multi-user simulation, and successfully realizes The encoding and decoding process is analyzed, and the performance simulation and analysis of the core switching module of the four-layer multi-layer optical switching system-OCDM switching module are carried out, and the feasibility and superiority of the selected system are verified.

Core Switch Using Optically Induced Long-Period Gratings

We propose and theoretically demonstrate an optically induced long-period gratings (OLPGs) based core switching technique for multi-core fibers (MCFs). This switching technique is fully reconfigurable in terms of signal wavelength and input–output fiber cores. The switching window and its efficiency can be adjusted by changing the peak power and the shape of the pump pulses, respectively. Switching efficiencies of 76% were found. Furthermore, we also show that the switched signal can be reshaped by tuning the shape of the pump pulses.

Alternative RNA splicing modulates ribosomal composition and determines the spatial phenotype of glioblastoma cells.

Glioblastoma (GBM) is characterized by exceptionally high intratumoral heterogeneity. However, the molecular mechanisms underlying the origin of different GBM cell populations remain unclear. Here, we found that the compositions of ribosomes of GBM cells in the tumour core and edge differ due to alternative RNA splicing. The acidic pH in the core switches before messenger RNA splicing of the ribosomal gene RPL22L1 towards the RPL22L1b isoform. This allows cells to survive acidosis, increases stemness and correlates with worse patient outcome. Mechanistically, RPL22L1b promotes RNA splicing by interacting with lncMALAT1 in the nucleus and inducing its degradation. Contrarily, in the tumour edge region, RPL22L1a interacts with ribosomes in the cytoplasm and upregulates the translation of multiple messenger RNAs including TP53. We found that the RPL22L1 isoform switch is regulated by SRSF4 and identified a compound that inhibits this process and decreases tumour growth. These findings demonstrate how distinct GBM cell populations arise during tumour growth. Targeting this mechanism may decrease GBM heterogeneity and facilitate therapy.

Dynamic behaviour of a suspended bubble and its influence on the distribution of electric fields in insulating oil of an on-load tap-changer within power transformers

A small amount of gas bubbles generated in an on-load tap changer (OLTC) can cause partial discharges in the intense electric field region, which severely threaten the safe operation of the device. It is crucial to clarify the coupling mechanism of moving bubbles together with the electric field distribution in the OLTC. This paper analyzed the internal structure and operating principle of the OLTC switching core and clarified the electric field distribution of each component under working conditions. A 2D two-phase flow model was established based on a practical OLTC structure by using the phase-field method. We investigated the global dynamics of small bubbles in the OLTC under the combined action of flow and electric fields and generalized the mechanism of their impact on the spatiotemporal distribution of the electric field inside the OLTC. Finally, the influence of the characteristic parameters of the bubbles and the insulating oil on the insulation property of the OLTC were clarified. The results showed that the distribution of the electric field was closely related to the shapes of the bubbles and the initial field strength. When the oil quality was poor, there was a risk that the bubbles caused partial discharge, in which case, oil purification and filtration operations should take place. The oil flow velocity should be controlled within a specific range to ensure that the rapid passage of bubbles through the intense electric field area does not render distortions in the field strength significant. The smaller the bubble size is, the steeper the gradient of electric field becomes at the gas-oil interface, and the greater the field strength inside the bubble, more likely to cause the occurance of accidental discharges in the OLTC.

An Adaptive Multiobjective Genetic Algorithm with Multi-Strategy Fusion for Resource Allocation in Elastic Multi-Core Fiber Networks

Core switching on different links in optical networks enables network operators to allocate network resources more flexibly, so as to reduce the network request blocking ratio under limited resources. Facing a differentiated network environment and diversified user demands, network operators need to optimize multiple objectives that are independent and diversionary of each other, and to provide multiple resource allocation schemes whose objective values do not dominate each other. For the static routing, spectrum, and core assignment (RSCA) problem in elastic optical networks with multi-core fiber (MCF-EONs), there is no literature that simultaneously considers core switching and multiobjective optimization algorithms. This paper improves the existing models and algorithms to adapt to the RSCA problem. In this paper, the RSCA problem is formulated as an integer linear programming model to minimize both network request blocking and crosstalk ratios simultaneously by considering core switching and inter-core crosstalk. To solve the model efficiently, we, therefore, design a joint routing and core coding scheme supporting core switching and propose a multiobjective evolutionary algorithm based on decomposition with adaptation and multi-strategy fusion (MOEA/D-AMSF), which integrates the new mechanisms of hybrid initial population generation, adaptive crossover, and double-layer and multi-point mutation in different iteration stages. These new mechanisms accelerate algorithm convergence and enhance solution diversity. Simulation results show that the proposed algorithm can obtain more dominated and diverse solutions compared with the existing multiobjective algorithm without considering core switching.

Exploring Performance Parameters of Artificial Allosteric Protein Switches

Biological information processing networks rely on allosteric protein switches that dynamically interconvert biological signals. Construction of their artificial analogues is a central goal of synthetic biology and bioengineering. Receptor domain insertion is one of the leading methods for constructing chimeric protein switches. Here we present an in vitro expression-based platform for the analysis of chimeric protein libraries for which traditional cell survival or cytometric high throughput assays are not applicable. We utilise this platform to screen a focused library of chimeras between PQQ-glucose dehydrogenase and calmodulin. Using this approach, we identified 50 chimeras (approximately 23% of the library) that were activated by calmodulin-binding peptides. We analysed performance parameters of the active chimeras and demonstrated that their dynamic range and response times are anticorrelated, pointing to the existence of an inherent thermodynamic trade-off. We show that the structure of the ligand peptide affects both the response and activation kinetics of the biosensors suggesting that the structure of a ligand:receptor complex can influence the chimera’s activation pathway. In order to understand the extent of structural changes in the reporter protein induced by the receptor domains, we have analysed one of the chimeric molecules by CD spectroscopy and hydrogen–deuterium exchange mass spectrometry. We concluded that subtle ligand-induced changes in the receptor domain propagated into the GDH domain and affected residues important for substrate and cofactor binding. Finally, we used one of the identified chimeras to construct a two-component rapamycin biosensor and demonstrated that core switch optimisation translated into improved biosensor performance.

Commensurate vortex-core switching in magnetic nanodisks at gigahertz frequencies

The development of future spintronic applications requires a thorough and fundamental understanding of the magnetisation dynamics. Of particular interest are magnetic nanodisks, in which the vortex state emerges as a stable spin configuration. Here, we focus on how the vortex core polarisation can be reversed periodically by an oscillating magnetic field, applied perpendicularly to the disk's surface. By means of micromagnetic simulations, we demonstrate the presence of several subharmonic switching modes, i.e., the commensurate ratio between the switching frequency of the core and the driving frequency. The underlying mechanism of this periodic behaviour depends on the disk thickness. For thin disks, the core switches periodically due to resonant excitation of radial spin wave modes, while it is due to the breathing mode in the case of thick disks. However, overlap of both modes impedes periodic vortex core switching. For thin disks, the threshold field amplitude required for periodic switching can be lowered to about 30~mT by increasing the disk diameter. For thick disks, in contrast, the minimal field is largely unaffected by the disk diameter, as only the energy density of a central region around the vortex core is relevant to excite the breathing mode. Our results contribute to the understanding of the switching mechanisms in magnetic nanodisks, which are of technological interest due to their potential in non-volatile memory devices.

Core Selective Switch With Low Insertion Loss Over Ultra-Wide Wavelength Range for Spatial Channel Networks

The core selective switch (CSS) is an optical spatial switch that has been recently proposed as a key building block to achieve a scalable and low-insertion-loss spatial cross-connects for use in future spatial channel networks. In this paper, we report on a novel CSS design employing a two dimensionally arranged microlens-based multicore fiber (MCF) collimator array and a micro-electromechanical systems (MEMS) mirror array. The former enables precise alignment between MCFs and collimator lenses, and the latter yields polarization-independent high reflection over a wide wavelength range and a large tilt angle. Based on the design, a compact (∼50 mm) five-core <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1 \times 8$</tex-math></inline-formula> CSS prototype is fabricated. We experimentally show that the CSS prototype exhibits low insertion loss (1.2∼2.7 dB), low polarization dependent loss (< 0.25 dB), and low crosstalk (< <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$ - 30$</tex-math></inline-formula> dB) characteristics over an ultra-wide wavelength range from 1500 nm to 1630 nm. Bit-error-rate measurements using optical signals in the C-band, S-band, and L-band show that the CSS prototype incurs no optical signal-to-noise ratio penalty in spatial channel routing over an ultra-wide wavelength band.