Capacitated Network Research Articles

Study of a position-sensitive scintillator neutron detector prototype based on 6LiF/ZnS scintillator and silicon photomultiplier arrays readout

Due to the shortage of the 3He gas and its rapidly increasing price, scintillator detectors, the advantages of which are high spatial resolution and capability of detection in real time, become widely used in many neutron instruments. In this work, a position-sensitive neutron detector consisting of a 6LiF/ZnS scintillation screen and a silicon photomultiplier array linked to a capacitive network to detect the positions of incident neutrons, is constructed and tested. To evaluate the detector performance, a series of neutron beam experiments with the detector prototype were performed in the BL20 at the China Spallation Neutron Source. The spatial resolution was measured, and the energy-selective neutron imaging and Bragg edge measurements of a 316L stainless steel sample were performed. A sub-millimeter spatial resolution could be obtained for the detector prototype under study. The detector with such a high spatial resolution is promising for applications in neutron scattering experimental installations, especially for neutron single-crystal diffractometers.

A New In Situ Coaxial Capacitive Sensor Network for Debris Monitoring of Lubricating Oil.

Wear debris monitoring of lubricant oil is an important method to determine the health and failure mode of key components such as bearings and gears in rotatory machines. The permittivity of lubricant oil can be changed when the wear debris enters the oil. Capacitive sensing methods showed potential in monitoring debris in lubricant due to the simple structure and good response. In order to improve the detection sensitivity and reliability, this study proposes a new coaxial capacitive sensor network featured with parallel curved electrodes and non-parallel plane electrodes. As a kind of through-flow sensor, the proposed capacitive sensor network can be in situ integrated into the oil pipeline. The theoretical models of sensing mechanisms were established to figure out the relationship between the two types of capacitive sensors in the sensor network. The intensity distributions of the electric field in the coaxial capacitive sensor network are simulated to verify the theoretical analysis, and the effects of different debris sizes and debris numbers on the capacitance values were also simulated. Finally, the theoretical model and simulation results were experimentally validated to verify the feasibility of the proposed sensor network.

Paths and flows for centrality measures in networks

AbstractWe consider the number of paths that must pass through a subset X of vertices of a capacitated network N in a maximum sequence of arc‐disjoint paths connecting two vertices y and z. We consider then the difference between the maximum flow value from y to z in N and the maximum flow value from y to z in the network obtained from N by setting to zero the capacities of arcs incident to X. When X is a singleton, those quantities are involved in defining and computing the flow betweenness centrality and are commonly identified without any rigorous proof justifying the identification. On the basis of a deep analysis of the interplay between paths and flows, we prove that, when X is a singleton, those quantities coincide. Moreover they are both equal to the global flow that must pass through X in any maximum flow from y to z. On the other hand, we prove that, when X has at least two elements, those quantities and the global flow that must pass through X in any maximum flow from y to z may be different from each other. We next show that, by means of the considered quantities, two conceptually different group centrality measures, based on paths and flows respectively, can be naturally defined. Such group centrality measures both extend the flow betweenness centrality to groups of vertices and are proved to satisfy a desirable form of monotonicity.

Intermodal transportation in humanitarian logistics with an application to a Turkish network using retrospective analysis

In the event of disruptions in a transportation network following a disaster, humanitarian organizations find it challenging to provide basic requirements for beneficiaries. Demand may be met using intermodal transportation as an alternative when the unimodal transportation infrastructure is damaged. This study proposes a mathematical model for utilizing intermodal transportation using 40 ft standard containers while delivering relief supplies by road, rail, and sea modes. The proposed model is a capacitated multi-period multicommodity intermodal network flow model in which relief supplies are delivered to beneficiaries in three echelons (i.e., supply, intermodal hub, and demand). The Turkish Disaster and Emergency Management Presidency's container warehouses (i.e., supply), logistics centers and container ports (i.e., intermodal hubs) are utilized to test the mathematical model with real-life demand parameters. Retrospective analysis was performed to determine the most frequently used container warehouses, logistics centers, and origin-destination pairs. Hence, an increase in operational capacity and infrastructure reinforcement is recommended to mitigate the effects of future disasters. We found that intermodal transportation is more robust to network disruptions in rapidly delivering relief supplies. We observed that intermodal transportation is utilized in disasters with more than 50,000 beneficiaries or disrupted unimodal infrastructure. For instance, after the future Istanbul earthquake, it would be impossible to deliver the relief materials only by road transportation within the urgent response period. Thus, the benefits of intermodal transportation in humanitarian logistics are more visible in large-scale disasters in which transportation resources are scarce, and transportation infrastructure is more likely to be destroyed.

Probability Distributions on Partially Ordered Sets and Network Interdiction Games

This article poses the following problem: Does there exist a probability distribution over subsets of a finite partially ordered set (poset), such that a set of constraints involving marginal probabilities of the poset’s elements and maximal chains is satisfied? We present a combinatorial algorithm to positively resolve this question. The algorithm can be implemented in polynomial time in the special case where maximal chain probabilities are affine functions of their elements. This existence problem is relevant for the equilibrium characterization of a generic strategic interdiction game on a capacitated flow network. The game involves a routing entity that sends its flow through the network while facing path transportation costs and an interdictor who simultaneously interdicts one or more edges while facing edge interdiction costs. Using our existence result on posets and strict complementary slackness in linear programming, we show that the Nash equilibria of this game can be fully described using primal and dual solutions of a minimum-cost circulation problem. Our analysis provides a new characterization of the critical components in the interdiction game. It also leads to a polynomial-time approach for equilibrium computation.

Observing Mesoscopic Nucleic Acid Capacitance Effect and Mismatch Impact via Graphene Transistors.

This work reports a molecular-scale capacitance effect of the double helical nucleic acid duplex structure for the first time. By quantitatively conducting large sample measurements of the electrostatic field effect using a type of high-accuracy graphene transistor biosensor, an unusual charge-transport behavior is observed in which the end-immobilized nucleic acid duplexes can store a part of ionization electrons like molecular capacitors, other than electric conductors. To elucidate this discovery, a cascaded capacitive network model is proposed as a novel equivalent circuit of nucleic acid duplexes, expanding the point-charge approximation model, by which the partial charge-transport observation is reasonably attributed to an electron-redistribution behavior within the capacitive network. Furthermore, it is experimentally confirmed that base-pair mismatches hinder the charge transport in double helical duplexes, and lead to directly identifiable alterations in electrostatic field effects. The bioelectronic principle of mismatch impact is also self-consistently explained by the newly proposed capacitive network model. The mesoscopic nucleic acid capacitance effect may enable a new kind of label-free nucleic acid analysis tool based on electronic transistor devices. The in situ and real-time nucleic acid detections for virus biomarkers, somatic mutations, and genome editing off-target may thus be predictable.

Original Application of Stop-Band Negative Group Delay Microwave Passive Circuit for Two-Step Stair Phase Shifter Designing

This paper investigates on the theorization, design, fabrication and measurement of original phase shifter (PS) operating with two-step stair phase behavior. The innovative stair PS is designed with unfamiliar stop-band (SB) negative group delay (NGD) passive circuit. The elementary unfamiliar SB-NGD topology constituted by resistive, inductive, and capacitive lumped network is described. Acting as an RF and microwave circuit, the S-matrix model is expressed in function the RLC-network parameters. Thus, the canonical form of unfamiliar SB-NGD transfer function (TF) represented by the transmission coefficient is established. The unfamiliar SB-NGD circuit equations in terms of the NGD parameters are formulated. The established theory is validated comparing the calculated, simulated, and measured S-parameters and group delays (GDs). Results with a very good agreement showing unfamiliar SB-NGD behavior are observed around the central frequency 2.45 GHz and bandwidth of 100 MHz. An innovative application of unfamiliar SB-NGD function for the communication system front-end is developed. The developed application concept of unfamiliar SB-NGD circuit is illustrated by designing a microwave device operating as a PS presenting a two-step stair response completely original behavior. The basic theory, design and implementation of the two-step stair PS concept are introduced. To validate the two-step stair PS principle, a proof of concept (PoC) is designed based distributed element based inductive and capacitive microstrip elements. The simulated and measured results of the PS PoC are in good agreement. The experimental results confirm the feasibility of two-step stair PS with phase jumping from −70°±4° (from 2 GHz to 2.3 GHz) to −104°±2° (from 2.6 GHz to 3.0 GHz). The investigated unfamiliar SB-NGD function-based stair PS is promising for future development 5G and 6G communication system.

Multi-product distribution in multi-supplier combined and capacitated transport networks

The paper tackles the problem of capacitated transport vehicle routing for the combined distribution of multiple products for multiple suppliers. This real-life urban distribution-planning problem requires a solution that identifies a set of routes for carrying out the combined distribution in extensive multi-supplier distribution networks. The paper describes the development of a novel 0-1 model for modelling the routing problem to aid in the optimum routes for the combined distribution with the objective of minimising the total distance travelled that significantly affects the transportation cost while satisfying demand and capacity constraints. For conducting a comparative analysis, the paper deploys a solution procedure that quickly leads to a good routing solution. The paper introduces a case study as an application scenario with three case problems for illustrating the suitability and applicability of the proposed approach. The results are not surprising; the novel 0-1 model provides optimal solutions and outperforms the solution procedure.

Multi-Echelon Inventory Management for a Non-Stationary Capacitated Distribution Network

Multi-Echelon Inventory Management for a Non-Stationary Capacitated Distribution Network

Design and Analysis of High-Performance and Low-Power Quaternary Latch,Quaternary D Flip-Flop and XY Flip-Flop

Multiple-valued logic (MVL) circuits propose a number of possible improvements to current VLSI circuit designs. Forexample, serious difficulties with limitations on the number of connections between an integrated circuit and the outside world(pinout concern) and also the number of links within the circuit encountered in some VLSI circuit synthesis could be greatlyreduced if signals in the circuit could assume four or more states instead of only two. This research work shows a quaternarylogic-based latch, a level-sensitive flop, and an edge-sensitive flop. In most of the cases it is seen that a sequential digital circuitproduces two outputs which are complementary to each other. But in most of the designs, there is no need of having both theoutputs of the flip-flops, so one of the quaternary outputs can be removed from the circuit, resulting in a decrease in area andstatic power. In quaternary circuits, several power sources or a single power supply source are employed. Those that haveseveral sources of supply use less energy. In multiple-valued logic we need the design to have multiple logic levels, like inquaternary logic, GND is used for logic ‘0’, 1/3Vdd is used for logic ‘1’, 2/3Vdd is for logic ‘2’, and Vdd is for logic ‘3’. Themulti-Vdd design method is incompatible with the purpose of reducing the inter-chip and intra-chip connections. In order toresolve this, a capacitive divider network is used while designing. The QFF is demonstrated with the necessary simulationresults using LTSpice tool and the simulations are performed using 32nm technology file. Finally, a quaternary shift register isbuilt to demonstrate the applicability and appropriate operation of the proposed QFF in larger sequential circuits.

Multi-product distribution in multi-supplier combined and capacitated transport networks

Multi-product distribution in multi-supplier combined and capacitated transport networks

A Mixed-Integer Linear Programming Model for Simultaneous Optimal Reconfiguration and Optimal Placement of Capacitor Banks in Distribution Networks

Optimal capacitor placement and network reconfiguration are well-known methods to minimize losses, enhance reliability, and improve the voltage profile of electric distribution networks (EDNs). Distribution network reconfiguration (DNR) consists of altering the system topology by changing the states of ties and sectionalizing switches, while the optimal placement of capacitors (OPCAs) involves sizing and finding the optimal location of capacitor banks within the distribution network for reactive power control. DNR and OPCAs are challenging optimization problems involving both integer and continuous decision variables. Due to the nature of these problems (combinatorial optimization problems), most approaches that deal with DNR and OPCAs resort to metaheuristic techniques, and they are limited to applications in small-size distribution networks. Although these techniques have proven to be effective when dealing with non-convex optimization problems, their main drawbacks lie in the fact that they require the fine-tuning of several parameters and do not guarantee the finding of a globally optimal solution. This paper presents a mixed-integer linear programming (MILP) model to solve simultaneous DNR and OPCAs in radial distribution networks. The proposed model can be solved by commercially available software; it guarantees to obtain globally optimal solutions and requires low computational effort when compared with metaheuristic techniques employed for the same purpose. Several tests were carried out on seven benchmark EDNs ranging from 33 to 417 buses. In all cases, the proposed methodology was able to replicate the results reported in the specialized literature. Regarding the DNR alone, a novel solution was found for the 119-bus test system which is 1.86 % better than that previously reported in the specialized literature. Furthermore, new solutions are reported for the simultaneous optimal DNR and OPCAs for medium and large-size EDNs. The power loss reduction in the test system ranged from 21.12 % to 68.93 % evidencing the positive impact of the proposed approach in EDNs.

Analysis of LCR Network Circuits with Exponential Sources by New Integral Transform Gupta Transform

In science and engineering, the analysis of Inductor, Capacitor and Resistor (LCR) network circuits is a principal course and is generally done by applying calculus or integral transforms. In this paper, we will analyze LCR network circuits with exponential excitation sources by applying the new integral transform ‘Gupta Transform’ and obtain their responses in the form of current or voltage. This paper presents the application of the ‘Gupta Transform’ and proves its applicability for analyzing the LCR network circuits with exponential excitation sources and concludes that ‘Gupta Transform’ like other methods or approaches is also an effective and simple tool.

Charge stability diagram of serial triple quantum dots

<sec>Serial triple quantum dot (STQD) systems have received extensive attention in the past decade, not only because quantum dot scaling up is an indispensable ingredient for integrations, but also due to the fact that specific charge states of STQD can be employed to achieve fast full-electrical manipulation of spin qubits. For the latter, a comprehensive understanding of the relationship between neighboring charge occupancy states of STQD is essential for three-electron exchange-only spin qubit-based quantum computations. Charge stability diagram is usually employed to map out the charge occupation states about the plunger gate voltages of STQDs and to study the degeneracy among charge occupation states. Experimentally, two- rather than three-dimensional charge stability diagram was obtained in a lot of early studies by keeping one of plunger gates unchanged to reduce complexity. The obtained two-dimensional diagram can only provide limited information and is subject to blurred boundary of charge occupation states due to the low tunneling current and the energy level broading effects. It is, therefore, challenge to searching for the working points where quantum manipulation can be performed promptly and accurately.</sec><sec>In principle, three-dimensional charge occupation stability diagram can be efficiently constructed by numerical simulations based on constant interaction (CI) model. In this study, we calculate the electrochemical potential of STQD about three plunger gate voltages by using the CI model-based capacitance network to reproduce any desired two-dimensional charge stability diagram. The simulated diagram not only well accords with the diagrams obtained from the early experimental data of STQD, but also provides high clarity of the charge state boundaries with tunable parameters. The systematical study of two-dimensional charge stability diagram reviews the energy degeneracy triple and quadruple points of STQD charge occupation states and concludes the energy degeneracy points in three types to compare with experimental data. For each of the energy degeneracy points, we discuss both the electron and hole transport by using the electrochemical potential alignment schematics. We reveal the common and unique triple points of STQD in comparison with those of double quantum dot. The quadruple points of STQD are also addressed in the manipulation of quantum cellular automata and quantum logical gate. The comprehensive understanding of these energy degeneracy points can efficiently guide experiments to build an optimal working point of the STQD system for quantum computations and simulations.</sec>

Strategic bidding in price coupled regions

With the emerging deregulated electricity markets, a part of the electricity trading takes place in day-ahead markets where producers and retailers place bids in order to maximize their profit. We present a price-maker model for strategic bidding from the perspective of a producer in Price Coupled Regions (PCR) considering a capacitated transmission network between local day-ahead markets. The aim for the bidder is to establish a production plan and set its bids taking into consideration the reaction of the market. We consider the problem as deterministic, that is, the bids of the competitors are known in advance. We are facing a bilevel optimization problem where the first level is a Unit Commitment problem, modeled as a Mixed Integer Linear Program (MILP), and the second level models a market equilibrium problem through a Linear Program. The problem is first reformulated as a single level problem. Properties of the optimal spot prices are studied to obtain an extended formulation that is linearized and tightened using new valid inequalities. Several properties of the spot prices allow to reduce significantly the number of binary variables. Two novel heuristics are proposed, the first applicable in PCR, the second for general formulations with Special Ordered Sets (SOS) of type 1. Our computational experiments highlights the risk of a loss for the bidder if some aspects usually not considered in the literature, such as Price Coupled Regions, or an accurate UC problem, are not taken into account. They also show that the reformulation techniques, combined with new valid inequalities, allow to solve much larger instances than the current state-of-the-art. Finally, our experiments also show that the proposed heuristics deliver very high quality solutions in a short computation time.

Robust omnichannel retail operations with the implementation of ship-from-store

In this paper, we consider an omnichannel retailer (o-tailer) selling multiple products through a capacitated retail network over a multi-period horizon, where each inventory facility is equipped with a certain ability to fulfill the orders regardless of the channel. We study omnichannel retail operations with the implementation of ship-from-store to minimize the o-tailer’s expected total cost. At the start of each period, the o-tailer determines how much to replenish each product for each distribution center (DC), and how to allocate its inventory from DCs to different stores. At the end of each period, the o-tailer decides from which DCs and/or stores to fulfill the realized online demands. We formulate the problem as a multi-period stochastic optimization model and adopt a robust two-phase approach (RTA) to solve it. Phase 1 determines the binary replenishment decisions using a target-oriented robust optimization approach, whereas Phase 2 uses a linear decision rule to adaptively determine the replenishment, allocation, and fulfillment quantities. Numerical experiments suggest that the RTA outperforms existing approaches and can efficiently produce good-quality and robust solutions for realistic problem instances. A further sensitivity analysis explores the impacts of various system parameters on the RTA’s performance and the benefits of omnichannel fulfilment.

Suitability of passive RC-network-based inductorless bridged-T as a bandpass NGD circuit

PurposeThe purpose of this paper is to study, a bridged-T topology with inductorless passive network used as a bandpass (BP) negative group delay (NGD) function.Design/methodology/approachThe BP NGD topology under study is composed of an inductorless passive resistive capacitive network. The circuit analysis is elaborated from the equivalent impedance matrix. Then, the analytical model of the C-shunt bridged-T topology voltage transfer function is established. The BP NGD analysis of the considered topology is developed in function of the bridged-T parameters. The NGD properties and characterizations of the proposed topology are analytically expressed. Moreover, the relevance of the BP NGD theory is verified with the design and fabrication of surface mounted device components-based proof-of-concept (PoC).FindingsFrom measurement results, the BP NGD network with −151 ns at the center frequency of 1 MHz over −6.6 dB attenuation is in very good agreement with the C-shunt bridged-T PoC.Originality/valueThis paper develops a mathematical modeling theory and measurement of a C-shunt bridged-T network circuit.

Novel Interleaved High Gain Boost Converter Using Switched Capacitor

The increase in global energy demand has led to increased research in harvesting solar energy. Solar energy is widely used in homes, electric vehicles and is a great solution to power remote areas. DC–DC converters are essential in extracting power from solar panels. One of the main problems in designing converters for solar energy applications is boosting the low output voltage of the solar panel to meaningful levels. While there are several topologies to achieve high gain, some of the problems faced by them are the extreme duty ratio, complex design and discontinuous input current. This paper presents a novel topology that uses an interleaved input, a voltage lift capacitor and a hybrid switched capacitor network to achieve high gain without an extreme duty ratio or bulky magnetics. The proposed converter is controlled using a microcontroller which regulates the output voltage. The voltage lift capacitor and the switched capacitor network enhances the voltage gain over a conventional boost converter without an extreme duty ratio. The analysis and design of the proposed converter are presented and verified with a 100 W prototype. The results show that the converter provides a gain of 10, at a duty ratio of 30%, while delivering the designed output power with considerably high efficiency.

Charge-Based Capacitive Self-Sensing With Continuous State Observation for Resonant Electrostatic MEMS Mirrors

This contribution presents charge-based capacitive self-sensing with a continuous full state observer for a parametrically driven resonant electrostatic 1D MEMS mirror considering precise and seamless estimation. Based on current integrators, series capacitances or a capacitance network the direct charge self-sensing principles are investigated and compared considering leakage currents, precision and a minimum implementation effort. In comparison to the other charge sensing methods, the proposed methods directly measure the charge changes while the drive voltage is switched on. Since resonant MEMS mirrors are driven by a rectangular signal, the direct self-sensing implies a lack of data when the drive voltage is switched off. A nonlinear observer is also proposed to estimate the full mirror state continuously based on an identified MEMS mirror model. The capacitive charge self-sensing methods achieve overall a high sensing precision of less than 0.14 % RMSE and the observer estimation error of the full state is below 1 % peak-to-peak error regardless of the availability of the charge self-sensing measurements, demonstrates accurate continuous full state estimation. [2021-0130]

Modeling and Quantifying Interaction of Information and Capacity in Public Transport Disruptions

Disruption in public transport networks has adverse implications for both passengers and service managers. To evaluate the effects of disruptions on passengers’ behaviour, various methods, simulation modules, and mathematical models are widely used. However, such methods included many assumptions for the sake of simplicity. We here use multiagent microsimulation modules to simulate complex real-life scenarios. Aspects that were never explicitly modelled together are the capacity of the network and the effect of disruption to on-board passengers, who might need to alight the disrupted services. In addition, our simulation and developed module provide a framework that can be applied for both transport planning and real-time management of disruption for the large-scale network. We formalize the agent-based assignment problem in capacitated transit networks for disrupted situations, where some information is available about the disruption. We extend a microsimulation environment to quantify precisely the impact and the number of agents directly and indirectly affected by the disruption, respectively, those passengers who cannot perform their trip because of disrupted services (directly affected passengers), and those passengers whose services are not disrupted but experience additional crowding effects (indirectly affected passengers). The outcomes are discussed both from passengers’ perspective and for extracting more general planning and policy recommendations. The modeling and solution approaches are applied to the multimodal public transport system of Zürich, Switzerland. Our results show that different information dissemination strategies have a large impact on direct and indirect effects. By earlier information dissemination, the direct effects get milder but larger in space, and indirect negative effects arise. The scenarios with the least information instead are very strongly affecting few passengers, while the less negative indirect effect for the rest of the network.