Flow Routing Research Articles

Latency-Sensitive Parallel Multi-Path Service Flow Routing With Segmented VNF Processing in NFV-Enabled Networks

Latency-Sensitive Parallel Multi-Path Service Flow Routing With Segmented VNF Processing in NFV-Enabled Networks

Autonomous Flow Routing for Near Real-Time Quality of Service Assurance

Autonomous Flow Routing for Near Real-Time Quality of Service Assurance

Usability test and implications of an activity allocation mapping in complex organizations: perceptions about a software by emergency room agents

PurposeProperly allocating an organization's activities within a building is vital to reducing the relational complexity arising from process–environment interactions. Multiple relationships are mapped, and certain interferences are only identified after these have been processed. The method/software employed for this task is Mapping Activity Environment Allocation (MAEA). However, data input and interpretation of results depend on the usability conditions of the organization's agents. This paper presents MAEA's usability test results.Design/methodology/approachTest sessions and interviews were carried out with seven agents registered at a University Hospital. Participants were instructed to think aloud during its use, and immediately afterward, responded to semi-structured interviews. Test sessions were audio recorded and screen captured.FindingsParticipants found the software easy to use and pointed out valuable implications for professional and academic use. In addition to relationship, priority and parallelism data, customized visualizations were created, including organizational charts, flowcharts and activity flow routes on the floor plan.Practical implicationsMAEA's simplicity allows non-designers to conduct evidence-based assessments and decisions. It allows designers to test their proposals during the programming and outline proposal stages.Social implicationsA more detailed definition of design requirements from the beginning increases the conditions to successfully achieve project goals.Originality/valueThe ability to map the allocation of activity-spaces in the pre-design phase of building architecture allows for early identification of interactions, aiding in the development of more robust project requirements during programming.

An accelerated Benders decomposition approach for virtual base station formation in stochastic Cloud-RANs

In Cloud-RANs, the baseband unit (BBU) is separated from the remote radio head (RRH) at the cell site and migrated to a server cloud to decrease deployment and maintenance costs. A base station (BS) can be formed as a network slice in which the virtual network functions (VNFs) of its BBU can be placed on any server by network virtualization (NFV) technology and logically connected by software-defined networking (SDN). However, the uncertain demands of users make it very difficult to determine a network slice with appropriate VNF placement and flow routing between VNFs. We aim to minimize the cost of providing BS services while meeting their time-varying demands. We consider the network slice scheme and fronthaul establishment jointly and formulate this as an integer linear programming (ILP) problem. We propose scenario classification Benders decomposition (CBD) based on Benders decomposition (BD) but with fewer Benders cuts, accelerating the solution convergence. Moreover, we propose an efficient heuristic approach to obtain good solutions for the ILP problem based on the solutions of its relaxed problems obtained by BD or CBD. The numerical experiments show that when combining our heuristic approach with CBD, the results are close to the optimal solutions of the ILP problem, while the computation time is significantly shorter than those of previous approaches.

Drought decreases cotton fiber strength by altering sucrose flow route.

The potential mechanisms by which drought restricts cotton fiber cell wall synthesis and fiber strength formation are still not fully understood. Herein, drought experiments were conducted using two upland cotton cultivars of Dexiamian 1 (drought-tolerant) and Yuzaomian 9110 (drought-sensitive). Results showed that drought notably reduced sucrose efflux from cottonseed coats to fibers by down-regulating the expression of GhSWEET10 and GhSWEET15 in outer cottonseed coats, leading to promoted sucrose accumulation in cottonseed coats but decreased sucrose accumulation in fibers. Within cotton fibers, drought restricted the hydrolysis from sucrose to UDPG by suppressing sucrose synthase activity, and drought favored the conversion of UDPG to β-1, 3-glucan rather than cellulose by up-regulating GhCALS5. Hence, cellulose content was reduced, which was the main reason for the decreased fiber strength under drought. Moreover, drought promoted lignin synthesis by up-regulating the expression of Gh4CL4, GhPAL9, GhCCR5, GhCAD11, and GhOMT6, which partly offset the negative influence of reduced cellulose content on fiber strength. Compared with Yuzaomian 9110, the drought-tolerance of Dexiamian 1 was evidenced in the following ways: (1) slighter blocked sucrose flow from seedcoat to fiber, (2) less β-1, 3-glucan accumulation, and (3) more lignin biosynthesis under drought. Overall, this study provides new insights into the mechanism of drought impacting cotton fiber strength formation.

Paleoecological niche modeling of Epiophlebia (Epiophlebioptera: Epiophlebiidae) reveals continuous distribution during the Last Glacial Maximum

Disjunct biogeographic patterns of similar species remain enigmatic within evolutionary biology. Disparate distributions typically reflect species responses to major historical events including past climate change, tectonics, dispersal, and local extinction. Paleo-ecological niche modeling (PaleoENM) has proven useful in inferring the causes of disjunct distributions within charismatic and well-studied taxa including mammals, plants, and birds, but remains under-explored in insects. The relictual Asian dragonfly genus Epiophlebia (Suborder Epiophlebioptera: Epiophlebiidae) allows us a novel opportunity to explore PaleoENM in the context of disjunct distributions due to their endemism to the Japanese islands, Himalayas, China, and North Korea. The aim of this paper is to investigate the potential causes behind the modern distribution of Epiophlebia by inferring the historical range of these species within the Last Glacial Maximum (LGM), thereby highlighting the utility of PaleoENM in the context of odonate biogeography. Our results indicate possible past routes of gene flow of Epiophlebia during the LGM due to high habitat suitability of the genus stretching from the Himalayas to Japan. Furthermore, our results predict several unsampled areas which have the potential to harbor new populations of the genus.

Extreme Flood Flow Routing for Panchet and Maithan Reservoirs of India Using Modified Puls Technique

An important aspect of economic considerations is the routing and safety of hydraulic storage facilities such as dams for extreme probable water flooding. The routing of dam reservoirs requires more attention for determining the magnitude of extreme probable flooding. Apparently, the type of structure, importance, and economic development of the surrounding area guide the routing criteria for choosing the extreme flood magnitude. The Maithan and Panchet Dams in India have faced several major floods with diversified magnitudes since 1978. The present study aims to estimate the storage and routing of extreme probable floodings for these two dams based on real-time flood data like inflow, outflow, and elevation for the extreme flood years of 1978, 2009, and 2014. Reservoir storages at different elevations are calculated from the initial storage volumes. For both reservoirs, discharge equations are derived and calculated at given elevations during extreme floods. The Modified Puls technique is used for routing extreme floods. At the end of each extreme flood in 1978, 2009, and 2014, the variation in outflow discharges at different elevations and flood hydrographs is predicted. Finally, estimated outflow discharges are compared with the actual outflow discharges for the given inflows during extreme floods. Using this approach, extreme floods that occurred in 1978 are predicted with less than 10% error. Outcomes from this study may help in the future planning and routing of flood-control detention facilities and in predicting the variation in outflow discharges at different elevations. Based on this work, alternative studies and regional drainage planning can also be carried out.

Simulation of the Entire Process of an Interbasin Water Transfer Project for Flow Routing

The flow routing process plays a crucial role in underpinning the execution of real-time operations within interbasin water transfer projects (IWTPs). However, the water transfer process within the supplying area is significantly affected by the time lag of water flow over extended distances, which results in a misalignment with the water demand process in the receiving area. Hence, there is an imperative need to investigate the flow routing patterns in long-distance water transfer processes. While MIKE11(2014 version) software and the Muskingum method are proficient in simulating flow routing within a water transfer network, they fall short in addressing issues arising from mixed free-surface-pressure flows in water transfer pipelines. This study enhanced the capabilities of the MIKE11(2014 version) software and the Muskingum method by introducing the Preissmann virtual narrow gap method to tackle the challenge of simulating mixed free-surface-pressure flows, a task unattainable by the model independently. This approach provides a clear elucidation of hydraulic characteristics within the water transfer network, encompassing flow rates and routing times. Furthermore, this is integrated with the Muskingum inverse method to compute the actual water demand process within the supplying area. This methodology is implemented in the context of the Han River to Wei River Diversion Project (HTWDP). The research findings reveal that the routing time for the Qinling water conveyance tunnel, under maximum design flow rate conditions, is 12.78 h, while for the south and north main lines, it stands at 15.85 and 20.15 h, respectively. These results underscore the significance of the time lag effect in long-distance water conveyance. It is noteworthy that the average errors between simulated and calculated values for the south and north main lines in the flow routing process are 0.45 m3/s and 0.51 m3/s, respectively. Compared to not using the Preissmann virtual narrow gap method, these errors are reduced by 59.82% and 70.35%, indicating a significant decrease in the discrepancy between simulated and calculated values through the adoption of the Preissmann virtual narrow gap method. This substantially improves the model’s fitting accuracy. Furthermore, the KGE indices for the flow routing model are all above 0.5, and the overall trend of the reverse flow routing process closely aligns with the simulated process. The relative errors for most time periods are constrained within a 5% range, demonstrating the reasonability and precision of the model.

Satellite-based precipitation error propagation in the hydrological modeling chain across China

Satellite-based precipitation products have great potential to promote hydrological modeling skill owing to the spatially homogeneous measurements they provide. However, satellite-based precipitation uncertainties and their hydrological impacts are poorly understood for different products and hydroclimate regions in China. This study comprehensively evaluates the error properties of ten satellite-based precipitation products and the precipitation error propagation characteristics in the hydrological modeling chain during the period 2001–2018. The results indicate that precipitation error tends to become smaller during the routing process for most satellite precipitation products; e.g., αRMAE, an error propagation ratio based on relative mean absolute error, decreased about 26% (from 0.58 to 0.43) when considering routing processes during hydrological simulation by using the PERSIANN-CDR satellite precipitation product. The linear slope of simulated streamflow against precipitation error greatly decreases (compared to that of simulated runoff) after flow routing of 366 catchments across China. This study also found that satellite-based precipitation product errors in hydrological simulations for drier and water-limited small catchments are more likely for amplify in the streamflow simulations. These findings are essential to improving understanding of the interactions between satellite-derived precipitation forcing and hydrological processes, and thus for improving the data accuracy of precipitation forcing for hydrological simulation in China.

A Concise Review on Applications of Bioinspired Algorithms in Electrical Power System

The integration of bioinspired algorithms into electrical power systems has gained significant attention in recent years due to their potential to address complex optimization and control problems. This paper presents a concise review on the applications of bioinspired algorithms in various aspects of electrical power systems, including power generation, transmission, distribution, and utilization. The review starts with an overview on electrical power system and then discusses the fundamental concepts of bioinspired algorithms. Next, the paper explores the application of bioinspired algorithms in power generation. It examines their use in optimizing the operation and scheduling of power plants, maximizing renewable energy integration, and improving the efficiency of power generation processes. Moving on to power transmission and distribution, the review discusses how bioinspired algorithms can be applied to optimize the routing and scheduling of power flows, enhance fault detection and diagnosis, and improve the reliability and security of the grid infrastructure. Furthermore, the utilization of bioinspired algorithms in power systems is explored, focusing on load forecasting, demand response, energy management, and power quality enhancement. Finally, the paper concludes with a summary of the main findings and future research directions. It emphasizes the need for further exploration of bioinspired algorithms in electrical power systems, including the development of hybrid algorithms and their integration with emerging technologies such as machine learning and big data analytics.

Real-Time Compact Digital Processing Chain for the Detection and Sorting of Neural Spikes from Implanted Microelectrode Arrays

Implantable microelectrodes arrays are used to record electrical signals from surrounding neurons and have led to incredible improvements in modern neuroscience research. Digital signals resulting from conditioning and the analog-to-digital conversion of neural spikes captured by microelectrodes arrays have to be elaborated in a dedicated DSP core devoted to a real-time spike-sorting process for the classification phase based on the source neurons from which they were emitted. On-chip spike-sorting is also essential to achieve enough data reduction to allow for wireless transmission within the power constraints imposed on implantable devices. The design of such integrated circuits must meet stringent constraints related to ultra-low power density and the minimum silicon area, as well as several application requirements. The aim of this work is to present real-time hardware architecture able to perform all the spike-sorting tasks on chip while satisfying the aforementioned stringent requirements related to this type of application. The proposed solution has been coded in VHDL language and simulated in the Cadence Xcelium tool to verify the functional behavior of the digital processing chain. Then, a synthesis and place and route flow has been carried out to implement the proposed architecture in both a 130 nm and a FD-SOI 28 nm CMOS process, with a 200 MHz clock frequency target. Post-layout simulations in the Cadence Xcelium tool confirmed the proper operation up to a 200 MHz clock frequency. The area occupation and power consumption of the proposed detection and clustering module are 0.2659 mm2/ch, 7.16 μW/ch, 0.0168 mm2/ch, and 0.47 μW/ch for the 130 nm and 28 nm implementation, respectively.

Optimized Planning of DU/CU Placement and Flow Routing in 5G Packet Xhaul Networks

Optimized Planning of DU/CU Placement and Flow Routing in 5G Packet Xhaul Networks

Numerical simulation of the complex flow field in a new recycling cyclone separator

Abstract The three-dimension flow field is simulated in a recycling cyclone separator using the Reynolds stress model (RSM) with Fluent 6.2. The results show that the unique design of the flow route of the recycling cyclone separator can improve the axial symmetry and the order of the inner flow field. The appearance of the eddy flow and the pressure drop of the recycling cyclone separator are also reduced. Moreover, the secondary circulation in the recycling cyclone separator is analyzed, which is useful for understanding the flow mechanism. This study provides a reference for further improvement of the recycling cyclone separator.

Optimizing in-band network telemetry problem

In-band network telemetry is a powerful framework for network monitoring. It allows the collection of telemetry data in real-time and provides network-wide visibility. However, depending on the routing of network flows and which telemetry data are collected, the network-wide visibility and the performance of monitoring applications may decrease. In this paper, we present the in-band network telemetry problem and extend the existing mathematical optimization models of the problem by proposing a new model that computes the routing of network flows. Results show that the new model outperforms existing models in term of network coverage and monitoring applications performance. The results of this work can be useful for network managers and enterprises to gain real-time insights into network performance.

Dynamic Routing of Multiple QoS-Required Flows in Cloud-Edge Autonomous Multi-Domain Data Center Networks

Dynamic Routing of Multiple QoS-Required Flows in Cloud-Edge Autonomous Multi-Domain Data Center Networks

Quantum-Assisted Joint Virtual Network Function Deployment and Maximum Flow Routing for Space Information Networks

Quantum-Assisted Joint Virtual Network Function Deployment and Maximum Flow Routing for Space Information Networks

Development of the gas chromatography/mass spectrometry-based aroma designer capable of modifying volatile chemical compositions in complex odors.

Many volatile organic compounds (VOCs) are used to produce various commercial products with aromas mimicking natural products. The VOCs responsible for aromas have been identified from many natural products. The current major strategy is to analyze chemical compositions and aroma qualities of individual VOCs using gas chromatography/mass spectrometry (GC/MS) and GC-olfactometry. However, such analyses cannot determine whether candidate VOCs contribute to the characteristic aroma in mixtures of many VOCs. In this study, we developed a GC/MS-based VOC collection/omission system that can modify the VOC compositions of samples easily and rapidly. The system is composed of GC/MS with a switching unit that can change gas flow routes between MS and a VOC collection device. We first applied this system to prepare gas samples for omission tests, and the aroma qualities of VOC mixtures with and without some VOCs were evaluated by panelists. If aroma qualities were different between the 2 samples, the omitted VOCs were likely key odorants. By collecting VOCs in a gas bag attached to the collection device and transferring some VOCs to MS, specific VOCs could be omitted easily from the VOC mixture. The system could prepare omission samples without chemical identification, preparation of each VOC, and laborious techniques for mixing VOCs, thus overcoming the limitations of previous methods of sample preparation. Finally, the system was used to prepare artificial aromas by replacing VOC compositions between different samples for screening of key odorants. In conclusion, the system developed here can improve aroma research by identifying key odorants from natural products.

Experimental investigation on enhancement of heat transfer in a straight tube heat exchanger using twisted tape inserts and nano fluids- effect of turbulent and laminar flow characteristics

One of the most significant groups of thermal energy handling equipment utilized in industries is heat exchangers. Their particular uses include chemical processing, waste heat recovery, space heating and air conditioning, and power generation. Most people consider heat exchangers to be complicated machines. Double-pipe heat exchangers are easy to build and analyze. However, given their extensive usage in industries, their significance is unquestionable. They have undergone several improvements to impact energy, reduce material costs, and thereby mitigate environmental deterioration. In industry, heat exchangers are commonly utilized for both heating and cooling purposes. Heat passes via the dividing walls of a recuperator, a form of heat exchanger that has distinct flow routes for each fluid along its tubes. Typically, the base fluid is water, ethylene glycol or oil, and the nano-particles are composed of metals, oxides or carbides. Nanofluid's ability to increase the rate of exchanging the heat in a variety of heat devices is experimentally assessed since adding nanoparticles to the base fluid improves its thermophysical characteristics. The use of inserts and nanofluids together significantly improves heat transmission.

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ ПРОЦЕСІВ ФУНКЦІОНУВАННЯ АВТОМАТИЗОВАНИХ СИСТЕМ ВІЙСЬКОВОГО РАДІОЗВ’ЯЗКУ В УМОВАХ ЇХ ЗАХИСТУ ВІД РАДІОРОЗВІДКИ

The article reveals the basic theoretical provisions and the essence of the approach to modeling the processes of functioning of automated military radio communication systems in terms of their protection against radio reconnaissance. An algorithm for determining rational radio exchange routes with low intelligence availability in an automated military radio communication system is proposed, which is the basis for solving the problem of multi-path routing and takes into account, in addition to the known limitations, the restrictions on the permissible intelligence availability of information flow routes, which is essential for military radio communication. A mathematical model of the functioning of an automated military radio communication system has been developed, which for the first time: takes into account the process of its protection against radio reconnaissance by radio exchange along rational routes with low intelligence availability; is based on the tensor dependencies of the coefficients of intelligence availability of individual direct radio communication lines on the quality indicators of information exchange in the elementary basis of the structure of the automated military radio communication system with their subsequent transformation to tensor dependencies of the coefficients The proposed theoretical positions can be used in the creation of training complexes (training base) based on artificial intelligence in order to increase the efficiency of troop training.

Decentralized control of flow in complex networks

A decentralized control algorithm for routing flow in complex networks is proposed. The aim is to fairly distribute the supply/demand among the nodes while maintaining maximum flow in the network and satisfying the flow limits of the nodes and links. The algorithm is also used for flow re-routing after a failure in (or attack on) a network to avoid a cascading failure while maintaining the maximum flow in the network. The proposed algorithm is based only on the information about the closest neighbours of each node. Consensus rules are used to achieve fairness between the nodes in the network. The performance of the proposed algorithm is demonstrated by simulations.