Reconfigurable Complex Research Articles

Parameterized Complexity of Reconfiguration of Atoms

Parameterized Complexity of Reconfiguration of Atoms

Michelson Interferometric Methods for Full Optical Complex Convolution.

Optical real-time data processing is advancing fields like tensor algebra acceleration, cryptography, and digital holography. This technology offers advantages such as reduced complexity through optical fast Fourier transform and passive dot-product multiplication. In this study, the proposed Reconfigurable Complex Convolution Module (RCCM) is capable of independently modulating both phase and amplitude over two million pixels. This research is relevant for applications in optical computing, hardware acceleration, encryption, and machine learning, where precise signal modulation is crucial. We demonstrate simultaneous amplitude and phase modulation of an optical two-dimensional signal in a thin lens's Fourier plane. Utilizing two spatial light modulators (SLMs) in a Michelson interferometer placed in the focal plane of two Fourier lenses, our system enables full modulation in a 4F system's Fourier domain. This setup addresses challenges like SLMs' non-linear inter-pixel crosstalk and variable modulation efficiency. The integration of these technologies in the RCCM contributes to the advancement of optical computing and related fields.

On the complexity of distance-d independent set reconfiguration

For a fixed positive integer d≥2, a distance-d independent set (DdIS) of a graph is a vertex-subset whose distance between any two members is at least d. Imagine that there is a token placed on each member of a DdIS. Two DdISs are adjacent under Token Sliding (TS) if one can be obtained from the other by moving a token from one vertex to one of its unoccupied adjacent vertices. Under Token Jumping (TJ), the target vertex needs not to be adjacent to the original one. The Distance-dIndependent Set Reconfiguration (DdISR) problem under TS/TJ asks if there is a corresponding sequence of adjacent DdISs that transforms one given DdIS into another. The problem for d=2, also known as the Independent Set Reconfiguration problem, has been well-studied in the literature and its computational complexity on several graph classes has been known. In this paper, we study the computational complexity of DdISR on different graphs under TS and TJ for any fixed d≥3. On chordal graphs, we show that DdISR under TJ is in P when d is even and PSPACE-complete when d is odd. On split graphs, there is an interesting complexity dichotomy: DdISR is PSPACE-complete for d=2 but in P for d=3 under TS, while under TJ it is in P for d=2 but PSPACE-complete for d=3. Additionally, certain well-known hardness results for d=2 on perfect graphs and planar graphs of maximum degree three and bounded bandwidth can be extended for d≥3.

Dynamically reconfigurable complex liquid crystal emulsions

ABSTRACT Complex emulsions, containing liquid crystals (LCs) and immiscible oils such as fluorocarbon or silicone oils, present innovative functionalities in soft materials. These emulsions exhibit dynamic reconfiguration in droplet morphology and internal LC organisation, expanding applications in optics, sensing, and active matter. This review highlights the evolution and potential of LC-containing complex emulsions. Emphasis is placed on emulsions featuring dynamic and reversible morphological transformations and LC reorganisation, underpinning their suitability for tunable micro-lenses, chemical sensing, and biosensing. Nematic LCs within complex emulsions allow for topological defect-driven functionalization, attaching antibodies to induce substantial changes in the LC director field upon interfacial recognition events. This feature may facilitate the development of ultrasensitive chemical and biological sensors. Moreover, cholesteric LCs, through their selective reflection, enable the rapid and sensitive detection of foodborne pathogens. The controlled assembly of magnetic nanoparticles at interfaces illustrates advancements towards magnetic field-responsive and active colloids. Future perspectives include exploiting these properties for intelligent colloidal systems capable of autonomous behaviour, and furthering applications in dynamic photonic devices, high-security identification tags, and responsive lens systems.

Traversability, Reconfiguration, and Reachability in the Gadget Framework

Consider an agent traversing a graph of “gadgets”, where each gadget has local state that changes with each traversal by the agent according to specified rules. Prior work has studied the computational complexity of deciding whether the agent can reach a specified location, a problem we call reachability. This paper introduces new goals for the agent, aiming to characterize when the computational complexity of these problems is the same or differs from that of reachability. First we characterize the complexity of universal traversal—where the goal is to traverse every gadget at least once—for DAG gadgets (partially), one-state gadgets, and reversible deterministic gadgets. Then we study the complexity of reconfiguration—where the goal is to bring the system of gadgets to a specified state. We prove many cases PSPACE-complete, and show in some cases that reconfiguration is strictly harder than reachability, while in other cases, reachability is strictly harder than reconfiguration.

Miniaturized Antenna Array-Based Novel Metamaterial Technology for Reconfigurable MIMO Systems.

In this work, a highly miniaturized microstrip antenna array based on two elements is proposed for multiple inputs multiple outputs (MIMO) application systems at sub-6 GHz frequency bands. The antenna is structured from a meander line in conjugate with an interdigital capacitor when excited through the monopole basic antenna. The proposed antenna elements are separated with a Minkowski factor-shaped metamaterial (MTM) column to achieve a separation distance (D) of 0.08λ at 3 GHz when printed on an FR-4 substrate. Later on, the antenna performance in terms of bandwidth and gain is controlled using a photonic process based on optical active switches based on light-dependent resistances (LDR). Therefore, the reconfiguration complexity with such a technique can be eliminated significantly without the need for a biasing circuit. The antenna design was conducted through several parametric studies to arrive at the optimal design that realizes the frequency bandwidth between 3 and 5.5 GHz with a maximum gain of about 4.5 dBi when all LDR terminals are off. For a wireless channel performance study-based massive MIMO environment, the proposed antenna is suitable to be configured in arrays of 64 × 64 elements. From this study, it was found the maximum bit error rate (BER) does not exceed 0.15 with a channel capacity (CC) of 2 Gbps. For validation, the antenna was fabricated based on two elements and tested experimentally. Finally, it was revealed that the measured results agree very well with simulations after comparing the theoretical calculations with the measured data.

On reconfigurability of target sets

We study the problem of deciding reconfigurability of target sets of a graph. Given a graph G with vertex thresholds τ, consider a dynamic process in which vertex v becomes activated once at least τ(v) of its neighbors are activated. A vertex set S is called a target set if all vertices of G would be activated when initially activating vertices of S. In the Target Set Reconfiguration problem, given two target sets X and Y of the same size, we are required to determine whether X can be transformed into Y by repeatedly swapping one vertex in the current set with another vertex not in the current set preserving every intermediate set as a target set. In this paper, we investigate the complexity of Target Set Reconfiguration in restricted cases. On the hardness side, we prove that Target Set Reconfiguration is PSPACE-complete on bipartite planar graphs of degree 3 and 4 and of threshold 2, bipartite 3-regular graphs and planar 3-regular graphs of threshold 1 and 2, and split graphs, which is in contrast to the fact that a special case called Vertex Cover Reconfiguration is in P for the last graph class. On the positive side, we present a polynomial-time algorithm for Target Set Reconfiguration on graphs of maximum degree 2 and trees. The latter result can be thought of as a generalization of that for Vertex Cover Reconfiguration.

A 0.015mW quasi-passive reconfigurable complex band-pass filter for analog baseband

A 0.015mW quasi-passive reconfigurable complex band-pass filter for analog baseband

Chemical design of self-propelled Janus droplets

Chemical design of self-propelled Janus droplets

On the Parameterized Complexity of Reconfiguration of Connected Dominating Sets

In a reconfiguration version of a decision problem \(\mathcal {Q}\) the input is an instance of \(\mathcal {Q}\) and two feasible solutions S and T. The objective is to determine whether there exists a step-by-step transformation between S and T such that all intermediate steps also constitute feasible solutions. In this work, we study the parameterized complexity of the Connected Dominating Set Reconfiguration problem (CDS-R). It was shown in previous work that the Dominating Set Reconfiguration problem (DS-R) parameterized by k, the maximum allowed size of a dominating set in a reconfiguration sequence, is fixed-parameter tractable on all graphs that exclude a biclique \(K_{d,d}\) as a subgraph, for some constant \(d \ge 1\). We show that the additional connectivity constraint makes the problem much harder, namely, that CDS-R is W[1]-hard parameterized by \(k+\ell \), the maximum allowed size of a dominating set plus the length of the reconfiguration sequence, already on 5-degenerate graphs. On the positive side, we show that CDS-R parameterized by k is fixed-parameter tractable, and in fact admits a polynomial kernel on planar graphs.

Multi-Band Transmission Using Reconfigurable Complex Multi-Band Delta Sigma Polar Modulator

This brief presents a new reconfigurable complex multi-band delta sigma polar modulator (CMB-DSPM) architecture for multi-band transmission. In this brief, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6^{\mathrm{ th}}$ </tex-math></inline-formula> order band-pass delta sigma modulator (DSM) is designed and implemented for reconfigurable triple-band transmission. The proposed DSM architecture utilizes the advantage of a complex DSM structure to reduce the required processing block and polar quantizer to reduce the quantization noise. The proposed CMB-DSPM architecture improves the in-band and out-of-band performance in terms of signal-to-noise distortion ratio (SNDR) and coding efficiency (CE), respectively. The proposed scheme is validated in MATLAB/SIMULINK-based digital signal processing platform using three 5 MHz long-term evolution (LTE) signals. The results show up to 12.4 dB improvement in SNDR and 12.3% improvement in CE compared to the standard cartesian DSM architecture. The measured EVM is below 3%, which shows the good in-band performance of the proposed scheme.

Development of Multi-Disciplinary Green-BOM to Maintain Sustainability in Reconfigurable Manufacturing Systems

The reconfigurable manufacturing system (RMS) appears to be eco-friendly while coping with rapidly changing market demands. However, there remains a lack of discussion or research regarding sustainability or environment-friendly functions within RMS. In this study, the reconfiguration planning problem is introduced to represent the core issues within the RMS. Reconfiguration occurs depending on new demands or conditions in the company by reconfiguring machines, such as removing, adding, or changing parts, giving considerable consideration to arrangement of machines, known as configurations in RMS. Therefore, reconfiguration process is always strongly connected to cost, energy consumption, and, more importantly, data management. The complexity of reconfiguration, product variation, and development processes requires tools that are capable of managing multi-disciplinary bill-of-material(BOM) or product data and providing a better collaboration support for data/information tracking while maintaining sustainability. This paper proposes a multi-disciplinary green bill-of-material (MDG-BOM)—an improved Green-BOM concept—with an additional multi-disciplinary feature to minimize emissions and hazardous materials during product development, as well as manage product information across multiple disciplines during the reconfiguration process. A smart spreadsheet for managing MDG-BOM was developed to allow multiple departments to integrate multiple sources of CAD design data and monitor/track changes throughout each step of the process.

Three-Phase Symmetric Distribution Network Fast Dynamic Reconfiguration Based on Timing-Constrained Hierarchical Clustering Algorithm

This paper develops a novel dynamic three-phase symmetric distribution network reconfiguration (DNR) approach based on hierarchical clustering with timing constraints, which can divide the time period according to the time-varying symmetric load demand and symmetric distributed generations (DGs) output condition for a given time interval. The significance of the proposed technique is that by approximating the cluster center as the load status and DGs output status of the corresponding period, in this way, the intractable dynamic reconfiguration problem can be recast as multiple single-stage static three-phase symmetric DNR problems, which can effectively reduce the complexity of the three-phase symmetric dynamic reconfiguration. Furthermore, an improved fireworks algorithm considering heuristic rules (H-IFWA) is proposed and investigated to efficiently manage each single-stage static three-phase symmetric DNR problem. In order to avoid trapping into a local optimum or to facilitate the computational performance, the power moment method and the coding method based on heuristic rules are employed to reduce the solution space. The effectiveness of the proposed H-IFWA is validated on the IEEE 33, 119-bus system and a practical-scale Taiwan power company (TPC) 84-bus test system with DGs.

Reconfigurable complex emulsions: Design, properties, and applications

Reconfigurable complex emulsions, which consist of multiphase droplets that can change morphology between encapsulated and Janus shapes, have become of recent fundamental and applied interest due to their unique stimuli-responsive characteristics. The newfound ability to dynamically change the structure and interfaces of droplets provides exciting opportunities for exploiting the properties and applications of fluids in ways not before possible, such as to create tunable lenses or droplet-based sensors. Droplet morphological reconfiguration, which is easily induced upon alteration of the balance of interfacial tensions, can be triggered in response to stimuli including pH, light, enzymes, temperature, and surfactants. This review describes recent advances involving reconfigurable complex droplet design, properties, and applications, highlighting both the opportunities and challenges associated with harnessing complex emulsions as responsive materials. We focus primarily on emulsions in which all droplet phases are immiscible with each other and the continuous phase, such as multiphase oil droplets dispersed in water or multiphase aqueous droplets dispersed in oil. The ability to manipulate the ordering of liquid interfaces in an emulsion while maintaining droplet stability has greatly enabled new directions for emulsion research and applications. Harnessing the dynamic structure and properties of reconfigurable complex emulsions presents a new frontier in the design of responsive materials relevant to optics, sensing, and active matter.

Controlled Cooperative Wetting Enabled Heterogeneous Structured 3D Morphing Transducers

AbstractA unique microfluidics approach for functional hydrogel patterning with multilayered heterogeneous structures is presented. Prepolymer solution droplets with differentiated sodium acrylate concentrations are dispensed/printed in a wetting‐controlled “two‐parallel plate” (TPP, like a Hele‐Shaw Cell) system. The gelation within the system enables hydrogel bilayer structures with reconfigurable 3D deformations driven by in‐plane and through‐thickness heterogeneity under stimuli‐responsive mask‐less swelling/deswelling. The cooperation between swelling mismatch of functional groups results in a higher complexity of 3D reconfiguration in responding to discrete levels of stimulation inputs. This facile patterning technology with an in‐built ionic hierarchy can be scaled up/down with advanced transducing functionalities in various fields.

Flexible reconfigurable GNSS RF receiver for portable application of Internet of Things

A fully integrated single input, dual-channel, single-band reconfigurable GNSS radio frequency receiver supporting GPS, BD2 and Galileo systems is designed and implemented in a 0.18 ​μm CMOS process for portable Internet of Things applications. The receiver incorporates a single RF front-end, low-power fractional-N synthesizer, and reconfigurable complex band-pass filter, which can be flexibly configured to receive GPS L1/BD2 B1 or GPS L1/Galileo E1, and any of these signals separately, and can also effectively simplify the design complexity of the receiver and reduce power consumption. Moreover, a flexible frequency plan is employed to meet the different frequency requirements of the receiver. While drawing 16 ​mA current from a 1.8 ​V supply, this RF receiver achieves a total noise figure of 1.79 ​dB, a maximum voltage gain of 108 ​dB, a gain dynamic range of 56 ​dB and the input third-order intercept point of -18.09 dBm and -23.66 dBm at 1575 ​MHz and 1561 ​MHz, respectively, with an active die area of 1.86 ​mm2.

Polyelectrolyte hydrogel capsules as stabilizers for reconfigurable complex emulsions

Polyelectrolyte capsules stabilize biphasic oil droplets while preserving droplet reconfigurability in the presence of surfactants.

A Chaos-Based Complex Micro-instruction Set for Mitigating Instruction Reverse Engineering

Chaos computing provides a large number of functions from a single hardware. Large-scale reconfigurability can be achieved flexibly by tuning only a few parameters from a chaos-based computing system. Implementation of reconfigurable complex functions from a single chaos circuit can alleviate area and power concerns due to decreasing technology nodes. It is possible to make a multi-input multi-output complex instruction set using the chaos-generated functionalities where operations are more uniform than conventional implementations. Lack of uniformity in implementation of instructions in traditional computing system provides opportunity for attackers to reverse engineer based on side channel power analysis. In this paper, it is proposed that chaos-based implementation of a complex instruction set is immune to classification-based reverse engineering attack. Cross obfuscation and self obfuscation schemes are proposed in this work which leverage reconfigurability of chaotic system for obfuscating the power profile of the instruction set and it has been made immune to reverse engineering attacks. The design utilizes 3-input multi-output instructions by using a single chaotic iterative map. We analyzed the immunity of this design against classification-based reverse engineering attack for six different classification algorithms with five dimensionality reduction techniques.

Dynamic Complex Liquid Crystal Emulsions.

We report a new class of dynamically reconfigurable complex colloids comprising immiscible liquid crystals (LCs) and fluorocarbon oils. Producing stable spherical droplets requires the utilization of appropriately designed surfactants to reduce the high intrinsic surface tension between the LCs and the fluorocarbon oils that initially lead to nonspherical, "snowman-shaped" Janus droplets. After stabilizing the interfaces via surfactants, the LC droplet morphology can be dynamically switched between LC-in-fluorocarbon-in-water double emulsions (LC/F/W), spherical Janus emulsions, and inverted double emulsions (fluorocarbon-in-LC-in-water, F/LC/W) in response to changes in the surrounding surfactants. These stabilization methods can be extended to smectic LCs to create droplets with more complex internal arrangements and expand the range of LC emulsions that can be prepared. In addition, by using new mesogenic surfactants that control the LC director field at each LC interface, we prepare LC complex colloids exhibiting different internal configurations. The ability to control the LC anchoring conditions made it possible to create topological singularities as powerful templates for the precision assembly of antibodies at the droplets' interface. These dynamic LC complex colloids of controllable morphology and LC orientation are rich soft material platforms that will find utility in a variety of sensing applications.

Reconfigurable directional coupler in lithium niobate crystal fabricated by three-dimensional femtosecond laser focal field engineering

For crystals, depressed cladding waveguides have advantages such as preservation of the spectroscopic as well as non-linear properties and the capability to guide both horizontal and vertical polarization modes, but fabrication is always quite time consuming. In addition, it is usually difficult to couple modes propagating in different depressed cladding waveguides through evanescent field overlap, so it is often required to dynamically reconfigure photonic waveguide devices using external fields for classical or quantum applications. Here, we experimentally demonstrate the single-scan femtosecond laser transverse writing of depressed cladding waveguides to form a 2×2 directional coupler inside lithium niobate crystal, which is integrated with two deeply embedded microelectrodes on both sides of the interaction region to reconfigure the coupling. By focal field engineering of the femtosecond laser, we specially generate a three-dimensional longitudinally oriented ring-shaped focal intensity profile composed of 16 discrete spots to simultaneously write the entire cladding region. The fabricated waveguides exhibit good single guided modes in two orthogonal polarizations at 1550 nm. By applying voltage to the deeply embedded microelectrodes fabricated with the femtosecond laser ablation followed by selective electroless plating, we successfully facilitate the light coupling from the input arm to the cross arm and thus actively tune the splitting ratio. These results open new important perspectives in the efficient fabrication of reconfigurable complex three-dimensional devices in crystals based on depressed cladding waveguides.