Description Of System Behavior Research Articles

Osmotic injury and cytotoxicity for hMSCs in contact with Me2SO: The effect of cell size distribution

The paper discusses the impact of cell size on cytotoxicity and expansion lysis during the osmotic excursions resulting from the contact of hMSCs from UCB with Me2SO. It builds upon the mathematical model recently presented by the authors, which pertains to a population of cells with uniform size. The objective is to enhance the model's relevance by incorporating the more realistic scenario of cell size distribution, utilizing a Population Balance Equations approach. The study compares the capability of the multiple-sized model to the single-sized one to describe system behavior experimentally measured through cytofluorimetry and Coulter counter when, first, suspending hMSCs in hypertonic solutions of Me2SO (at varying osmolality, system temperature, and contact times), and then (at room temperature) pelleting by centrifugation before suspending the cells back to isotonic conditions. Simulations demonstrate that expansion lysis and cytotoxic effect are not affected by cell size for the specific system hMSCs/Me2SO, thus confirming what was found so far by the authors through a single-size model. On the other hand, simulations show that, when varying the adjustable parameters of the model that are expected to change from cell to cell lineages, expansion lysis is sensitive to cell size, while cytotoxicity is not, being mainly influenced by external CPA concentration and contact duration. More specifically, it is found that smaller cells suffer expansion lysis more than larger ones. The findings suggest that different cells from hMSCs may require a multiple-sized model to assess cell damage during osmotic excursions in cryopreservation.

Enhanced methanol reforming gas fuel cell system with electrochemical hydrogen pump: Conceptual design, system analysis, and multi-objective optimization

In this work, two methanol-reforming gas fuel cell systems coupled with an electrochemical hydrogen pump (EHP), namely, EHP pre-coupling and post-coupling fuel cell systems were proposed to achieve performance enhancement. A back propagation neural network surrogate model was established for the two systems to accurately describe system behavior, and a second-generation multi-objective non-dominated genetic algorithm was utilized for addressing the multi-objective optimization problem encompassing net output power, carbon mass-specific emission and the levelized cost of electricity. The linear non-weighted multi-attribute preference and technique for order preference by similarity to ideal solution multi-attribute decision-making methods were employed to select the optimal solutions. The optimized EHP pre-coupling fuel cell system exhibited lower carbon emissions (0.69 kgCO2/(kW·h)) and higher net output power (126.02 kW) compared to previous studies. While the EHP post-coupling system achieves a lower levelized cost of electricity (0.36 USD/(kW·h)), and stronger system stability (total efficiency reduction less 1 %). Both EHP-coupling systems offer viable process enhancements for fuel cell systems.

Low Harmonics Plug-in Home Charging Electric Vehicle Battery Charger Simulation Model of Zero Crossing

Harmonic currents are high in conventional rectifiers. The previous work proposed a new battery charger circuit to reduce harmonics effect and improve total harmonic distortion (THD). The design and development of a home charging electric vehicle battery charger circuit should anticipate potential issues. For this reason, the proposed battery charger, buck chopper, and zero cross circuits must be simulated before real hardware implementation. Simulation and simulation models are needed to describe system behaviour because experimentation might be dangerous, expensive, and time-consuming. This paper describes a simulation model of a zero-crossing circuit and its control algorithm, that provide control signals to a five-level single phase Multi Level Rectifier (MLR)) to draw the MLR for a clean sinusoidal line current with low harmonics. The proposed circuit and the algorithms perform as expected when tested using MATLAB/Simulink and PROTEUS software.

Performance Case Study of Concrete Bridge-Rail Post on Deck Overhang

Concrete post-and-beam bridge rails are a common bridge-rail type in the U.S. However, direct investigations of their performance on bridge-deck overhangs are rare, and current specifications do not clearly address this rail type or the design of decks supporting them. In this paper, the results of a performance case study of concrete bridge-rail posts on deck overhangs are presented. This study included (1) bogie testing of a MASH TL-4 concrete post on an instrumented deck, (2) development and calibration of a corresponding LS-DYNA model, and (3) use of the calibrated model to further describe system behavior, evaluate the effect of common design alternatives on performance, and corroborate the system performance from a full-scale crash test. The results of this study indicated that current design methods of the AASHTO LRFD Bridge Design Specifications (BDS) resulted in a significant underestimation of lateral capacity, partially because their neglect of inertial resistance. In the bogie test of the concrete post, over 40% of the peak lateral resistance of the post was attributed to inertial effects. Similarly, the calibrated LS-DYNA model indicated that the full-scale system could withstand a simplified single-unit truck (SUT) loading consisting of a 150 kip pulse load while only sustaining minor damage, despite having a BDS-predicted capacity of 73 kips. Additional findings included a characterization of deck demands, performance effects of design alternatives, such as edge distance and slab thickness, and the influence of using straight versus hooked transverse deck bars.

Analysis of Networks and Digital Systems by Using the Novel Technique Based on Complex Fuzzy Soft Information

In the last few years, intelligent industrial systems and consumer electronics are being developed extensively and broadly. Fuzzy logic and fuzzy techniques that integrate these approaches are recognized as effective ways to realize such intelligent functions. These intelligent systems rely on fuzzy control techniques i.e., common sense rules to describe system behavior instead of complex mathematical models. This work provides solutions to such uncertainties and aids in the relative decision-making processes. To this end, an innovative concept of complex fuzzy soft relation (CFSR) is defined based on the Cartesian product (CP) between two complex fuzzy soft sets (CFSSs). The main goal of this analysis is to develop some new and valuable concepts which will be suitable for managing awkward and unreliable information in real-life problems. The proposed idea is more dominant and superior to the prevailing ideas, where the presented idea is the modified technique of two different theories, called fuzzy set (FS) and soft set (SS). In addition, some reliable results have also been proved. Moreover, an application of the proposed techniques is proposed which demonstrates the process of choosing a good network. Finally, the advantages of the proposed framework are explained by the comparison with pre-existing frameworks.

The theory of scaled electromagnetism

Scaled experimentation is an important experimental approach but is known to be limited by scale effects, which have the undesirable effect of changing the behaviour of a system with scale. Such behavioural changes with scale can on occasions be so marked as to make a scaled experiment almost worthless. Until very recently, there has been no universal solution to this problem with most scaled experiments founded on dimensional analysis and modified necessarily with ad hoc scaling rules. This article is concerned with the development and the application of a new approach to scaled experimentation called finite similitude for electro-magnetic systems. It is shown how the finite similitude theory can be applied to electromagnetism and the governing Maxwell equations in their macroscopic form. The ability of the theory to account for scale dependencies is investigated to reveal the benefits of performing two scaled experiments in describing system behaviour.

Analysis of wireless English multimedia communication based on spatial state model equation

Abstract In order to improve the quality of wireless English multimedia communication, according to the characteristics of space multimedia communication environment and communication equipment, this paper proposes a wireless English synchronous QoS control algorithm with low complexity and easy implementation. Using RTCPSRRTP timestamp and NTP absolute timestamp, the wireless English RTP timestamp is mapped to the same absolute reference clock (sender system time) respectively, and the wireless English synchronization detection decision rule is established according to the synchronization QoS performance requirements between wireless English media. Wireless English synchronization control system model at the receiver. At the receiving end, the wireless English stream is the main media stream and the video stream is the slave media stream. The synchronization detection and judgment is implemented in real time before the video frame is played. The synchronization between audio and video media is realized by corresponding synchronization control of wireless English playback. State space model reflects all the information of system dynamic behavior and is a complete description of system behavior. The state space model has a wide range of applications. It is not only suitable for SISO linear constant systems, but also suitable for nonlinear systems, time-varying systems, MIMO systems and stochastic systems. The more outstanding advantage is that the state space model adopts local calculation and uses the state variables inside the system to describe its dynamic characteristics. This property of local calculation not only greatly simplifies the mathematical expression of multi-dimensional system, but also facilitates the analysis and research of the system. The air link rate of the wireless transceiver is set to 512Kbps. The video is encoded based on H.264 and the audio is encoded based on G.729 Speech coding standard. Compared with the wireless English media synchronization control algorithm based on RTP / RTCP, the results show that the RMSE value after adopting the synchronization algorithm in this paper is reduced by 60.09% and 77.69% at most; Compared with the wireless English media synchronization control algorithm based on RTP / RTCP, the synchronization performance of this algorithm is better than the wireless English media synchronization control algorithm. The RMSE value is reduced by 2% on average and 5.2% at most. In addition, the synchronization control algorithm between wireless English media performs synchronization control by losing frames or pausing decoding before video decoding at the receiver, which affects the quality of wireless English video decoding and reconstruction.

Conformal coating of powders by magnetron sputtering

Applying a thin film coating to powder under vacuum conditions requires mechanical agitation of the powder to achieve a uniform coating on the surfaces of the powder particles. In this work, we develop a piston-crank mechanism for agitating powder, using mathematic descriptions of system behavior (dynamics, forces, and stresses) as well as operational experience to improve the design. The viability of the system is demonstrated by applying tungsten onto spherical copper powder to produce uniform, conformal coatings. The capability of the agitation system is compared to coatings produced using alternative agitation methods, revealing that the piston-crank mechanism produces a larger coating volume per energy input than these other techniques.

Feedback loop reasoning in physiological contexts

ABSTRACT Feedback loop reasoning is an essential part of systems thinking, which includes the analysis and description of system behaviour and regulative measures. In feedback loops, every change can simultaneously represent a cause and an effect. Research on reasoning in feedback loops is limited to investigating students’ existing mental models. This thinking-aloud study extends insight to the field by providing causal loop diagrams to examine reasoning related to feedback loops. High school students (N = 30, 14–16 years) analysed system behaviours and regulative measures based on the regulation of blood glucose. We developed a category system examining students’ prior knowledge and different reasoning patterns (general feedback loop reasoning, reversing cause-effect relationships, and explanations of equilibrium). Our results indicate that students consider direct, or direct and incomplete indirect cause-effect relationships. However, their response patterns vary depending on different task types (system behaviour, regulative measures, and complex system behaviour). Regarding equilibrium, most students explained it through opposing external factors, while only a few considered feedback loop mechanisms that maintain equilibrium. Therefore, we would recommend that teachers distinguish between the hidden dynamics of regulative processes and the visible maintenance of stable conditions by using appropriate external representations to explain phenomena such as equilibrium.

Availability analysis of a permissioned blockchain with a lightweight consensus protocol

This paper offers a novel approach to the evaluation of provenance blockchain security and reliability using analytical methods for assessing system availability against malicious miner DoS attacks. In particular, we present the reliability and availability analysis of the LightWeight Mining (LWM) protocol for securing data provenance. Our analysis shows the reliability of the protocol and its ability to protect against malicious miner DoS attacks. We use digital signatures to prove integrity and non-repudiation of messages passing the system. We describe system behaviors using communicating sequential processes (CSP) to check for synchronization within a number of concurrent processes. Queuing theory is used to determine the average waiting time for client blockchain transactions when malicious miners work to slow the system. CSP and queuing theory jointly test the blockchain’s ability to make progress despite the presence of malicious miners. Further, the methodology described can be extended to other blockchain applications. Additional threats, beyond the malicious miner DoS attack, are reserved for future work.

Circuit Reduction of Heterogeneous Nonequilibrium Systems.

Predicting the behavior of heterogeneous nonequilibrium systems is currently analytically intractable. Consequently, complex biological systems have resisted unifying principles. Here, I introduce a mapping from dynamical systems to battery-resistor circuits. I show that in these transformed variables (i)arbitrary numbers of heterogeneous dynamical transitions can be reduced to a Thevenin equivalent resistor which is invariant to driving from equilibrium, (ii)resistors (together with the external driving sources) are sufficient to describe system behavior, and (iii)the resistor's directional symmetry leads to universal theorems of nonequilibrium behavior. This mapping is used to derive two general steady-state relations. First, for any cyclic process, the maximum amplification of any state is tightly bounded by the total dissipation of all states; experimental data are used to show that the master signal protein Ras achieves this bound. Second, for any process, the response of any reaction due to driving any other reaction is identical to the reciprocal response rescaled by the ratio of the corresponding Thevenin resistors. This result generalizes Onsager's reciprocal relation to the strongly driven regime and makes a testable prediction about how systems should be designed or evolved to maximize response. These analytic results represent a new perspective applicable to biological complexity and suggest that this mapping provides the natural variables to study heterogeneous nonequilibrium systems.

Application of system dynamics modelling in evaluating sustainability of low-input ruminant farming systems in Eastern Cape Province, South Africa

As a complex and dynamic concept that requires understanding from an ecological, economic and socio-cultural perspective, sustainability of agriculture and food systems is currently being strongly promoted by many governments and rural development practitioners. However, advances in monitoring and evaluating the sustainability of low-input ruminant farming are hindered by a lack of tools that simultaneously consider the interrelationships and dynamic behaviour of the different components of the system. Here we report on the application of a system dynamics model to evaluate the sustainability of low-input ruminant farming systems. This draws on nine indicators grouped as ecological; (soil organic matter, water availability and biomass supply), economic; (livestock productivity, labour supply and household income, and social: (farmer training, credence attributes of ruminant grazing systems and gender equality) to describe system behaviour over a ten-year period. The outputs from model simulations were used to compute index values for each of the indicators and the indices were subsequently used to evaluate sustainability of low-input ruminant farming systems. Household income, gender equality and farmer training had the highest sustainability indices whereas, soil organic matter and biomass supply recorded the lowest values. Overall, the low-input ruminant farming system was found to be moderately sustainable.

Physical foundation of optical smart antenna based on metamaterial and lithium niobate

In this work we present the main physical foundations of optical antenna array. This antenna array is based on the mirror system and lens system. To provide the necessary phase shift we propose two kind of structures: based on litium neobate and on ferrite-garnet. The main analytical expressions describing system behaviour are found for the first time. The results of calculation of the lens system parameters in the program ZEMAX are presented also.

ФИЗИЧЕСКИЕ ОСНОВЫ ПОСТРОЕНИЯ УПРАВЛЯЕМОЙ ОПТИЧЕСКОЙ АНТЕННЫ НА ОСНОВЕ НИОБАТА ЛИТИЯ

The article highlights a promising direction for high-speed signal transmission in wireless optical communication systems, namely, the use of optical antennas. Unlike fiber-optic systems which are sufficiently advanced today, today only one patent and one work are performed to describe the optical antenna array, which describes the optical antenna array for transmitting the optical signal in telecommunication networks. An important task in creating the antenna is selecting intelligent material to control the radiation pattern. The main physical foundations of optical antenna array have been described. The antenna array is based on the mirror system and lens system. To provide the necessary phase shift, two kinds of structures are proposed: of lithium niobate and of ferrite-garnet. The main analytical expressions describing system behavior are found for the first time.

Parameter estimation of Pendubot model using modified differential evolution algorithm

ABSTRACTParameter estimation plays a critical role in accurately describing system behavior through mathematical models such as a parametric dynamic model. In this paper, a modified differential evolution (MDE) algorithm is proposed to identify the parametric dynamic model of a Pendubot system with friction. In the MDE algorithm, the improvement is to focus on the mutation phase with a new mutation scheme in which multi-mutation operators are used, including rand/1 and best/1 for selecting target vectors in population. The performance of the MDE algorithm is tested on a set of fourth benchmark functions, and it is compared with the other algorithms such as a traditional differential evolution (DE), a hybrid DE (HDE) algorithm and a particle swarm optimization (PSO). The MDE algorithm is then used to identify the Pendubot’ parameters accurately. Experimental results demonstrate the high performance of the proposed method regarding robustness and accuracy.

A System Status Definition to Improve Behavior Description in Specifications Based on Constructal Law

System behavior description using states faces problems like state explosion, lack of clear definition of state, state identification and coordination between multiple agents. The goals of this work are to ease design activity, to reduce engineering efforts, and to mitigate project risks. The proposed way is to improve information flow during design by adding definitions and some protocols or rules for communicating a specification or design description. This work presented an objective definition of system status (way of interaction with the rest of the world) along other concepts. This work focused in definitions as mind entities and their importance to rationalize work and mitigate project risks during design. This article presented some simple examples to illustrate the advantages of each aspect of proposed definition of system status and discussed limits and exceptions for such definition. The key finding was the proposed definition which was the simplest while keeping completeness at a given product breakdown level. Such definition of status enforced formal segregation of needs and solutions, and eased the inclusion of behavior definition in specifications.

Combining process-based and correlative models improves predictions of climate change effects on Schistosoma mansoni transmission in eastern Africa.

Currently, two broad types of approach for predicting the impact of climate change on vector-borne diseases can be distinguished: i) empirical-statistical (correlative) approaches that use statistical models of relationships between vector and/or pathogen presence and environmental factors; and ii) process-based (mechanistic) approaches that seek to simulate detailed biological or epidemiological processes that explicitly describe system behavior. Both have advantages and disadvantages, but it is generally acknowledged that both approaches have value in assessing the response of species in general to climate change. Here, we combine a previously developed dynamic, agentbased model of the temperature-sensitive stages of the Schistosoma mansoni and intermediate host snail lifecycles, with a statistical model of snail habitat suitability for eastern Africa. Baseline model output compared to empirical prevalence data suggest that the combined model performs better than a temperature-driven model alone, and highlights the importance of including snail habitat suitability when modeling schistosomiasis risk. There was general agreement among models in predicting changes in risk, with 24-36% of the eastern Africa region predicted to experience an increase in risk of up-to 20% as a result of increasing temperatures over the next 50 years. Vice versa the models predicted a general decrease in risk in 30-37% of the study area. The snail habitat suitability models also suggest that anthropogenically altered habitat play a vital role for the current distribution of the intermediate snail host, and hence we stress the importance of accounting for land use changes in models of future changes in schistosomiasis risk.

Understanding how replication processes can maintain systems away from equilibrium using Algorithmic Information Theory

Replication can be envisaged as a computational process that is able to generate and maintain order far-from-equilibrium. Replication processes, can self-regulate, as the drive to replicate can counter degradation processes that impact on a system. The capability of replicated structures to access high quality energy and eject disorder allows Landauer's principle, in conjunction with Algorithmic Information Theory, to quantify the entropy requirements to maintain a system far-from-equilibrium. Using Landauer's principle, where destabilising processes, operating under the second law of thermodynamics, change the information content or the algorithmic entropy of a system by ΔH bits, replication processes can access order, eject disorder, and counter the change without outside interventions. Both diversity in replicated structures, and the coupling of different replicated systems, increase the ability of the system (or systems) to self-regulate in a changing environment as adaptation processes select those structures that use resources more efficiently. At the level of the structure, as selection processes minimise the information loss, the irreversibility is minimised. While each structure that emerges can be said to be more entropically efficient, as such replicating structures proliferate, the dissipation of the system as a whole is higher than would be the case for inert or simpler structures. While a detailed application to most real systems would be difficult, the approach may well be useful in understanding incremental changes to real systems and provide broad descriptions of system behaviour.

Investigation of Guided-Particle Transport for Noninvasive Healing of Damaged Piping Systems by Use of Electro-Magneto-Mechanical Methods

Summary Virtually all engineering applications involve the use of piping, conduits, and channels. In the petroleum industry, piping systems are extensively used in upstream and downstream processes. These piping systems often carry fluids that are corrosive, which leads to wear, cavitation, and cracking. The replacement of damaged piping systems can be quite expensive, both in terms of capital costs and in operational downtime. This motivates the present research on noninvasive healing of cracked piping systems. In this investigation, we propose to develop computational models for characterizing noninvasive repair strategies involving electromagnetically guided particles. The objective is to heal industrial-piping systems noninvasively, from the exterior of the system, during operation, resulting in no downtime and minimal relative cost. The particle accumulation at a target location is controlled by external electromagnetic/mechanical means. There are two primary effects that play a role for guiding the particles to the solid-fluid-interface/wall: mechanical shear caused by the fluid flow, and an electrical or magnetic force. In this work we develop and study a relationship that characterizes contributions of both, and ascertain how this relationship scales with characteristic physical parameters. Characteristic nondimensional parameters that describe system behavior are derived, and their role in design is illustrated. A detailed, fully 3D discrete-element-simulation framework is presented, and illustrated by use of a model problem of magnetically guided particles. The detailed particle behavior is considered to be regulated by three effects: the field strength, the mass-flow rate, and the wall interactions.

Water Diplomacy from a Duck's Perspective: Wildlife as Stakeholders in Water Management

AbstractContemporary water management strategies call for the inclusion of ecological research in the decision‐making process and emphasize environmentally sustainable management solutions. Most ecological information used in water management shares two problematic characteristics; 1) simplistic, phenomenological approaches and aggregated data that may not properly describe system behavior, and 2) a “zero‐sum” perspective treating ecological water needs as constraints to management. We argue that the newly devised Water Diplomacy Framework (WDF) can help overcome these shortcomings. We also provide a simple and intuitive method for integrating ecological factors into the WDF. We suggest that treating ecological phenomena as “surrogate stakeholders” in water negotiations increases opportunities for discovering mutual‐gains solutions and encourages a hypothesis‐based approach to research on the ecology of water management. By differentiating between the “positions” and “interests” of ecological stakeholder surrogates, decision‐makers can make greater use of the potential added value of ecosystem services in water management and avoid costly misunderstandings of the behavior of relevant ecological systems. We outline how the WDF can be applied to better integrate ecological factors into water management, and show how our approach could create synergies between endangered waterbird conservation and sustainable water management on the island of Oahu, Hawaii.