Multicommodity Flow Research Articles

Diagnostic workup of triple hit lymphoma by fine needle aspiration

Abstract Introduction/Objective Triple-hit lymphomas (THL) represent a rare and aggressive subset of high-grade B-cell lymphomas characterized by a triad of translocations involving MYC, BCL2, and BCL6. Patients with THL face poor outcomes when treated with the standard diffuse large B-cell lymphoma protocol. Thus, intensified regimens have emerged as a frontline strategy for managing these patients. Therefore, accurate diagnosis and molecular subclassification of these lymphomas are essential for guiding therapeutic decisions for these patients. Here, we report a case study detailing the diagnostic assessment of THL utilizing limited diagnostic material obtained through palpation-guided fine-needle aspiration (FNA). Methods/Case Report A 58-year-old male presented with a rapidly enlarging neck mass, accompanied by worsening dysphagia, pain, and fatigue over the course of two months. Laboratory testing showed leukocytosis and imaging studies revealed a partially necrotic, 7.8 x 9.1 x 9.4 cm right jugular nodal mass. The patient was referred to otolaryngology for further evaluation, where FNA of the mass was performed by the cytopathology team. The aspirate was sent for cytology with cell block and flow cytometry. The Romanowsky stain revealed abundant, large, discohesive cells with prominent nucleoli and scant cytoplasm with an abundance of lymphoglandular bodies in the background. Immunohistochemistry (IHC) on the cell block demonstrated BCL-2, BCL-6, and MYC expression, and a Ki-67 proliferation index >95%. Concurrent flow cytometric analyses showed an aberrant B-cell population expressing CD19, CD20, CD22, CD23 and surface lambda light chain. Further fluorescence in situ hybridization (FISH) analysis performed on the cell block confirmed gene rearrangements in BCL2, BCL6 and MYC, thereby classifying this patient’s disease as THL. Results (if a Case Study enter NA) NA Conclusion Diagnosing THL typically demands sufficient tissue for histology, cytology, flow cytometry, IHC, and molecular testing. Herein, we showcase a notable example where the diagnostic evaluation of THL was accomplished using limited material obtained from FNA. This case highlights the efficacy of conducting comprehensive diagnostic studies even when tissue availability is constrained. Utilizing cytologic samples not only streamlines the diagnostic process but also minimizes the need for patients to undergo additional invasive procedures, thus potentially reducing delays in diagnosis and therapeutic intervention.

MCMCF-Router: Multi-capacity Ordered Escape Routing Algorithms for Grid/Staggered Pin Array

Ordered escape routing (OER), which means that the pins need to be routed to the boundary of a pin array in a given order, is an important research topic in PCB design. Although OER has been widely investigated, most works assume that the routing capacity between two adjacent pins is just 1 and the structure of the pin array is a grid pin array. In this article, we focus on multi-capacity ordered escape routing (MC-OER) both in grid pin arrays and staggered pin arrays, which means that multiple wires are allowed to pass through between two adjacent pins. We first propose a multi-capacity multi-commodity flow (MC-MCF) model for the MC-OER problem. To accelerate the routing process, MCMCF-Router is proposed. In MCMCF-Router, a wiring resources driven partition strategy is proposed to reduce the problem size, followed by the approach based on routing conflicts. These approaches largely accelerate the MC-MCF model based method and increase the routability with minimal sacrifice on wire length. Experiments on various cases (with up to 525 pins) show that the proposed method achieves 100% routability within reasonable time (<810 seconds). Compared to the state-of-the-art works for single-capacity OER problems, MCMCF-Router performs similarly well or better.

Moderate hypothermic circulatory arrest with antegrade cerebral perfusion for the open repair of juxtarenal abdominal aortic aneurysm repair with shaggy aorta

Shaggy aorta is severe luminal surface degeneration of the aorta leading to an increased risk of plaque destabilization and embolization to the peripheral or visceral vessel beds. It represents a challenging clinical entity for both endovascular and open repair owing to potential atheroembolization, increased early morbidity and mortality, and poor long-term survival. Patients may be denied repair owing to its high risks. Herein, we present a novel approach to open repair of a juxtarenal abdominal aortic aneurysm with shaggy aorta using moderate hypothermic circulatory arrest with antegrade cerebral perfusion and concurrent flow modification to mitigate the risk of atheroma embolism.

Partial gravity flammability of cast PMMA rods in concurrent axial stagnation flow

Testing was performed in a partial gravity centrifuge drop vehicle in the Zero Gravity Research Facility with cast PMMA rods in concurrent axial buoyant stagnation flow to determine flammability limits as a function of partial gravity level. The partial gravity levels studied varied from 0.04 g to a simulated 1g for ambient oxygen concentrations from 13.2 % to 15.2 % O2 by volume at an average 57.6 kPa (8.4 PSIA) ambient pressure, which is very close to the anticipated Lunar habitat pressure. The PMMA flammability boundary as a function of oxygen concentration and gravity level has been determined at five gravity levels. Coriolis effects appear to be minimal in the stagnation region where the flame is stabilized while the tips of the flame do show some bending at the higher gravity levels. Lunar gravity levels are near the minimum in the oxygen - gravity level flammability boundary. This suggests that fire is a significant safety risk for future exploration missions to the Moon since materials are screened in normal gravity to evaluate their safe use in space. If normal gravity screening is not conservative, a material derating method will need to be applied to ensure the material is not flammable on the Moon. Since the blowoff boundary appears to be linear with forced flow velocity, it may be possible to conduct elevated forced flow blowoff testing that could then be extrapolated down to effective Lunar gravity levels to provide an oxygen delta between 1g and Lunar flammability limits to derate the material.

Two stage Ordered Escape Routing combined with LP and heuristic algorithm for large scaled PCB

The Ordered Escape Routing (OER) problem, which is an NP-hard problem, is critical to PCB design. Primary methods based on integer linear programming (ILP) work well on small-scale PCBs with fewer pins. However, when dealing with large-scale instances, traditional ILP strategies frequently cause time violations as the number of variables increases due to time-consuming preprocessing. In addition, heuristic algorithms have a time advantage when dealing with specific problems. In this paper, We propose an efficient two-stage escape routing method that employs LP for global routing and uses a heuristic algorithm to deal with the path intersection problem to minimize wiring length and runtime for large-scale PCBs. We first model the OER problem as a min-cost multi-commodity flow problem and use ILP to solve it. Then, we relax the non-crossing constraints and transform the ILP model into an LP model to reduce the runtime. we also construct a crossing graph according to the intersection of routing paths and propose a heuristic algorithm to locate congestion quickly. Finally, we reduce the local area capacity and allow global automatic congestion optimization. Compared with the state-of-the-art work, experimental results show that our method can reduce the routing time by 60% and handle larger-scale PCB escape routing problems.

An alternating direction multiplier method with variable neighborhood search for electric vehicle routing problem with time windows and battery swapping stations

This paper studies a real-world electric vehicle routing problem (EVRP). Specifically, it is an EVRP with time windows and battery swapping stations (EVRP_TWBSS). The EVRP_TWBSS considers the routing of electric vehicles (EVs), the determination of each electric vehicle’s battery level, and the selection of battery swapping stations. The criterion of EVRP_TWBSS is to minimize the operating costs. To simplify the structure of model, a time-discrete and multi-commodity flow model based on extended state-space-time network (TMFM_ESSTN) is established. Meanwhile, an alternating direction multiplier method with variable neighborhood search (ADMM_VNS) is presented to address the TMFM_ESSTN. In ADMM_VNS, the augmented lagrangian relaxation (ALR) model constructed from the TMFM_ESSTN is decomposed and linearized to a series of least cost vehicle routing subproblems through the linear augmented lagrangian relaxation (LALR) decomposed technique. Then, each subproblem is iteratively solved by using the dynamic programming and two special designed VNS strategies in ADMM_VNS iterative framework. The solution’s quality can be controlled to a certain extent through monitoring the gap between the lower and upper bounds obtained after each iteration. Test results on instances with different scales and a real-world instance based on partial road network in Kunming City demonstrate that ADMM_VNS can achieve smaller gaps and better solutions than several state-of-the-art algorithms. In which, ADMM_VNS can reduce the optimal gap by up to 2.27 % compared to the other state-of-the-art algorithms in small-scale instances. The gap of ADMM_VNS is calculated based on the lower bound and the upper bound in the large-scale instances and the real-world instance are 10.36 % and 1.57 %, respectively.

Effects of Fuel Bed Slope and Wind Direction on Flame Spread Characteristics Over a Bed of Pinus Silvestris Needles

ABSTRACT Important factors influencing the flame characteristics over a bed of dry pine needles from Siberian Boreal forests (Pinus silvestris) in lab-scale is provided. Factors such as slope of the fuel bed, wind velocity, and direction of spread (concurrent flow or opposed flow), which play significant roles in determining the flame spread rate, have been investigated. Systematic lab-scale experiments have been carried out in a wind tunnel with varying air velocities and on an inclined fuel bed in still air. Numerical simulations have been carried out using a three-dimensional physics-based flame spread model available in Fire Dynamics Simulator, and the results are validated against a wide range of measured flame characteristics. The validated numerical model is then used to simulate concurrent flow and opposed flow flame spread over a sloping fuel bed in the presence of wind. Gas phase temperature on and above the bed surface and total and radiative heat flux measurements for concurrent flow and opposed flow flame spread under the influence of wind as well as for upslope flame spread in still air are presented. A stationary flame propagation mode is observed for a flat fuel surface. Predicted temperature, flow, and species concentration fields have been reported for selected cases to understand the flow and flame dynamics in gas phase and within the fuel beds. These data serve as a validation of the numerical model used for simulating the experimental cases. Further, it can be used to validate popular fire models such as Fire Foam and Fire-Star 3D.

Effect of fluid direction and reactor structure on heat storage performance of Ca(OH)2/CaO based on shell-tube thermochemical energy storage device

The flow direction of the heat transfer fluid (HTF) and reactor structure inside the shell-tube heat exchanger has a significant impact on the heat transfer performance of the shell-tube reaction device. In this study, a comprehensive 3D multi-physics coupled model of a shell-tube fixed bed thermochemical energy storage (TCES) device is developed. The investigation delves into the influence of HTF flow direction and reactor structural design on a plethora of critical parameters including temperature distribution, steam pressure distribution, reaction extent, reaction time, heat transfer power, heat transfer efficiency, and heat storage efficiency within the reactor. The result indicates that the flow direction of HTF has an impact on the homogeneity of the reaction in the tube, and the countercurrent and concurrent flow can realize the gradient and homogeneous occurrence of the reaction in the tube, respectively. Both lessening the outer diameter of the device and increasing the diameter of the heat storage material filling tube can improve the average heat exchange efficiency and the average heat storage efficiency. Compared with the basic case (Basic case A), the optimized (Case D) heat storage device volume decreased by 13.38 %, the energy stored amount increased by 24.14 %, heat storage time shortened by 8.04 %, and heat storage efficiency increased by 32.14 %. Additionally, the inlet temperature and velocity still have an obvious influence on the thermal performance of the reactor after structural optimization. These research findings guide for improving the heat and mass transfer effect and working performance of the shell-tube fixed bed Ca(OH)2/CaO reactor.

On-demand mobility-as-a-Service platform assignment games with guaranteed stable outcomes

Mobility-as-a-Service (MaaS) systems are two-sided markets, with two mutually exclusive sets of agents, i.e., travelers/users and operators, forming a mobility ecosystem in which multiple operators compete or cooperate to serve customers under a governing platform provider. This study proposes a MaaS platform equilibrium model based on many-to-many assignment games incorporating both fixed-route transit services and mobility-on-demand (MOD) services. The matching problem is formulated as a convex multicommodity flow network design problem under congestion that captures the cost of accessing MOD services. The local stability conditions reflect a generalization of Wardrop's principles that include operators’ decisions. Due to the presence of congestion, the problem may result in non-stable designs, and a subsidy mechanism from the platform is proposed to guarantee local stability. A new exact solution algorithm to the matching problem is proposed based on a branch and bound framework with a Frank-Wolfe algorithm integrated with Lagrangian relaxation and subgradient optimization, which guarantees the optimality of the matching problem but not stability. A heuristic which integrates stability conditions and subsidy design is proposed, which reaches either an optimal MaaS platform equilibrium solution with global stability, or a feasible locally stable solution that may require subsidy. For the heuristic, a worst-case bound and condition for obtaining an exact solution are both identified. Two sets of reproducible numerical experiments are conducted. The first, on a toy network, verifies the model and algorithm, and illustrates the differences local and global stability. The second, on an expanded Sioux Falls network with 82 nodes and 748 links, derives generalizable insights about the model for coopetitive interdependencies between operators sharing the platform, handling congestion effects in MOD services, effects of local stability on investment impacts, and illustrating inequities that may arise under heterogeneous populations.

The integration of En route flow optimization, complex network clustering, and rule-based approach to airspace sub-sectorization for enhanced air traffic monitoring

This study proposes the use of a novel integrated framework for 2D en route airspace sub-sectorization. The integrated framework combines the multi-commodity flow optimization approach, complex network clustering approach, and Minimum Bounding Geometry (MBG)-coupled Rule-based Approach for boundary design. A decomposition-based discrete particle swarm optimization (DPSO) is used to solve the clustering problem. The output of the flow optimization is used as a guiding standard for the DPSO. Experimentations were performed using the Indian airspace sector to validate the framework and DPSO was run for different maximum number of generations (maxgen). The findings reveal that the multi-commodity flow approach captures system-wide flow operations. Clustering results corresponding to maxgen=100 and maxgen=150 perform best in terms of equitable and balanced distribution of cluster size and traffic load. The MBG-coupled Rule-based Approach leads to compact and convex sub-sector boundary design. Major implications of this research include dynamic adaptability of the integrated framework, increased sensitivity of sector design to network evolution, and a computationally tractable framework. The higher controllability of the proposed framework also offers an increased acceptance among practitioners.

Experimental Investigation of Threshold Velocities for Air-Water Two-Phase Flow in a Vertical Tube and Annular Channels

This work presents an experimental study of five threshold velocities for air-water flow in three different vertical channels. The measured threshold velocities included onset flooding (OF), end flooding (EF), onset deflooding (OD), end deflooding (ED), and minimum pressure (MP) velocities. The experimental system includes a transparent vertical tube of 52.5 mm inner diameter and 1500 mm length. The test channel can be easily changed from a tube to an annular shape by inserting a cylindrical test element. A counter-current or concurrent upward flow was achieved by blowing air upward from the channel’s bottom and flowing water from its top. The threshold velocities were determined by analyzing the pressure drop versus air superficial velocity. Findings revealed evident hysteresis between the end flooding and onset deflooding velocities. In contrast, the end deflooding and onset flooding velocities were found to be identical. The end flooding velocity was indifferent to the water’s superficial velocity for all three channel geometries. A generalized gas-liquid flow state diagram for vertical channels is developed based on the present empirical analysis for different threshold velocities.

Gas-liquid countercurrent flow characteristics in a microbubble column reactor

Countercurrent flow mode is widely utilized in many chemical unit operations due to its effective enhancement of mass transfer driving force. While the microbubble column reactor has garnered attention for its substantial gas–liquid specific surface area and fast mass transfer rate under the concurrent flow condition, countercurrent flow microbubble column reactors remain relatively underexplored. Consequently, in this study a novel microbubble generator device featuring gas–liquid co-crossing a microfiltration membrane was developed. This device could generate microbubbles with narrow size distribution, and proved suitable for integration into the countercurrent microbubble column reactor. Further investigation ensued to elucidate the operational principles of this dispersion method. Finally, the hydrodynamic behavior of the countercurrent microbubble column reactor was examined. Remarkably, a gas–liquid-specific surface area 2300 m2/m3 was reached, surpassing that of conventional bubble column reactors by a significant margin. New gas–liquid chemical processes and process intensification technologies could be developed accordingly.

Simultaneous measurement of velocity field of liquid–solid particle flow in pipelines and analysis of flow characteristics

The liquid–solid particle flow within a horizontal pipeline is a typical particle-laden flow. The interplay between loaded particles and carrier phase engenders significant complexities in the dynamic behavior of such flows. We investigated the dynamics of a liquid–solid particle flow featuring dilute, slightly buoyant, hundred-micron-sized spherical particles fully suspended in the turbulent flow in a pipe, where Re is 7038. Cases with solid volume fractions of 0, 2.67 × 10-4, 5.33 × 10-4, 8.00 × 10-4, 1.07 × 10-3 and 1.33 × 10-3 were considered in this study. Experimental measurement techniques were utilized to acquire images of particles in the two-phase flow across the entire flow field via optical field feedback. Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) were employed to simultaneously obtain liquid-phase velocity fields and particle trajectories. This approach allowed for a comprehensive depiction of the velocity field of each phase. Subsequently, a detailed explanation and analysis of the flow characteristics of the liquid–solid particle flow were provided based on the distribution of macroscopic velocity fields, the microscopic vorticity field, particle velocity vectors, and velocity slip. As a result, it was found that with the addition of solid particles and an increase in volume concentration, the drag effect of the solid phase and the trend of accumulation near the lower wall caused a decrease in the liquid phase velocity profile and deformation of the parabolic shape. In the liquid–solid particle flow with a volume concentration of 1.33 × 10-3, compared to the single-liquid phase flow, the standard deviation of velocity in the central region increased from 0.0097 m/s to 0.0159 m/s, and in the near-wall region, it increased from 0.0257 m/s to 0.0347 m/s, representing increases of 1.54 times and 1.26 times respectively. The proportion of medium vortices increased from 17 % to 30 %, nearly doubling. This study actively explores the concurrent measurement and flow characteristics of liquid–solid particle flow.

Integrating patients in time series clinical transcriptomics data.

Analysis of time series transcriptomics data from clinical trials is challenging. Such studies usually profile very few time points from several individuals with varying response patterns and dynamics. Current methods for these datasets are mainly based on linear, global orderings using visit times which do not account for the varying response rates and subgroups within a patient cohort. We developed a new method that utilizes multi-commodity flow algorithms for trajectory inference in large scale clinical studies. Recovered trajectories satisfy individual-based timing restrictions while integrating data from multiple patients. Testing the method on multiple drug datasets demonstrated an improved performance compared to prior approaches suggested for this task, while identifying novel disease subtypes that correspond to heterogeneous patient response patterns. The source code and instructions to download the data have been deposited on GitHub at https://github.com/euxhenh/Truffle.

Comparative flow and thermal transfer aspects of Casson Hybrid Nanofluid and Williamson Hybrid Nanofluid dispersed in the mixture of water and ethylene glycol with variable thermal conductivity

This manuscript is prepared to deal with the comparative fluid flow and thermal transportation aspects of Casson Hybrid Nanofluid and Williamson Hybrid Nanofluid dispersed in the mixture of water and 30% C2H6O2 over an exponentially stretching cylinder. The suction effect, MHD effect, and the impact of variable thermal conductivity are also incorporated into the concurrent flow model. The spherical-shaped Ag and MoS2 are used as nanoparticles. It has been established that the shear stress rate and Nusselt number are lesser for Williamson hybrid nanofluid as compared to hybrid nanofluid, but the opposite is the trend for Casson Hybrid Nanofluid. Also, the skin friction coefficient is very high in Casson Hybrid Nanofluid in comparison to Williamson Hybrid Nanofluid. In addition to this, the thermal transfer rate is found to be enhanced by up to more than 4% in Casson Hybrid Nanofluid as compared to Williamson Hybrid Nanofluid for all the parameters.

A robust PID and RLS controller for TCP/AQM system

Transmission Control Protocol (TCP) controlling congestion by peer-to-peer is challenging to handle communication with numerous concurrent TCP flows and heavy traffic loads. Therefore, TCP requires the active queue management (AQM) to assist in avoiding buffer bloat in intermediate devices. Thus, Some AQM controllers, such as Red, Codel, and Pie, have been proposed to control congestion better. However, these controllers are unable to overcome the drawbacks, including micro-burst streams, unfair competition of flows with different workloads, as well as sluggishly responding to congestion in heavy traffic, which degrade the performance of data transmission. To address these problems, in this paper, we proposed a queueing-delay-based AQM controller for TCP/AQM systems, namely PID-R. PID-R adopts two-level control components, i.e., the Proportional-Integral-Derivative (PID) algorithm and the recursive least squares (RLS) filter, and combines the advantages of the two parts. Meanwhile, we also constructed a new TCP/PID-R fluid model derived from TCP/AQM classical model. According to the model, PID-R parameters are determined to keep the TCP/PID-R system steady. The comprehensive simulation reveals that PID-R outperforms the state-of-the-art AQM controllers.

Designing compact, connected and gap-free reserves with systematic reserve site selection models

Protected areas play a crucial role in current global policies to mitigate the erosion of biodiversity and systematic reserve site selection models are increasingly involved in their design. These models address the optimisation problem that seeks to cover spaces hosting biodiversity features with nature reserves at a minimum cost for human activities. To increase the likelihood of a successful implementation, reserves need to be spatially consistent. Widely used decision support tools such as Marxan and PrioritizR commonly enforce compactness indirectly by penalising the reserve perimeter in the objective function. Few other optimisation models explicitly consider spatial properties such as limited fragmentation, connectivity of selected sites, and buffer zones around them, etc. So far, no reserve site selection model can guarantee the production of a connected, compact, and gap-free reserve all at once. The impossibility of designing reserve solutions with desirable spatial properties using existing models makes it difficult to implement such solutions in the real world. Therefore, we propose a mixed-integer linear program to build a reserve that is connected, compact, and gap-free. To enforce these spatial attributes within a reserve site selection model, we used a multicommodity flow approach. We tested the computational feasibility of our model on generated instances and the real instance of Fernando de Noronha. The results indicate that a single model can be used to enforce compactness, connectivity, and the absence of gaps. Using this optimisation model, conservation practitioners can design reserve solutions with desirable spatial properties, thereby increasing the likelihood of a successful implementation.

MRD‐GAN: Multi‐representation discrimination GAN for enhancing the diversity of the generated data

AbstractThe generative adversarial network (GAN) is a highly effective member of the generative models category and is extensively employed for generating realistic samples across various domains. The fundamental concept behind GAN involves two networks, a generator and a discriminator, competing against each other. During the training process, generator and discriminator networks encounter several issues that can potentially affect the quality and diversity of the generated samples. One such critical issue is mode collapse, where the generator fails to create varied samples. To tackle this issue, this article introduces a GAN approach called the multi‐representation discrimination GAN (MRD‐GAN). In this approach, the discriminator supports concurrent network discrimination flows to manage different representations of the data through various transformation functions, such as dimension rescaling, brightness adjustment, and gamma correction applied to the input data of the discriminator. We use a fusion function to aggregate the output of all flows and return a consolidated loss value to update the generator's weights. Hence, the discriminator conveys diverse feedback to the generator. The proposed approach has been evaluated on four distinct benchmarks, namely CelebA, Cifar‐10, Fashion‐Mnist, and Mnist. The experimental results demonstrate that the proposed approach surpasses the existing state‐of‐the‐art GAN models in terms of FID metric that measures the diversity of the generated samples. Significantly, the proposed approach demonstrates remarkable FID scores of 14.02, 30.19, 9.42, and 3.14 on the CelebA, Cifar‐10, Fashion‐Mnist, and Mnist datasets, respectively.

Hartmann Flow of Two-Layered Fluids in Horizontal and Inclined Channels

The effect of a transverse magnetic field on two-phase stratified flow in horizontal and inclined channels is studied. The lower heavier phase is assumed to be an electrical conductor (e.g., liquid metal), while the upper lighter phase is fully dielectric (e.g., gas). The flow is defined by prescribed flow rates in each phase, so the unknown frictional pressure gradient and location of the interface separating the phases (holdup) are found as part of the whole solution. It is shown that the solution of such a two-phase Hartmann flow is determined by four dimensionless parameters: the phases’ viscosity and flow-rate ratios, the inclination parameter, and the Hartmann number. The changes in velocity profiles, holdups, and pressure gradients with variations in the magnetic field and the phases’ flow-rate ratio are reported. The potential lubrication effect of the gas layer and pumping power reduction are found to be limited to low magnetic field strength. The effect of the magnetic field strength on the possibility of obtaining countercurrent flow and multiple flow states in concurrent upward and downward flows, and the associated flow characteristics, such as velocity profiles, back-flow phenomena, and pressure gradient, are explored. It is shown that increasing the magnetic field strength reduces the flow-rate range for which multiple solutions are obtained in concurrent flows and the flow-rate range where countercurrent flow is feasible.

Code and Data Repository for Computing Bipath Multicommodity Flows with Constraint Programming–Based Branch-and-Price-and-Cut

Code and Data Repository for Computing Bipath Multicommodity Flows with Constraint Programming–Based Branch-and-Price-and-Cut