Open System Model Research Articles

Exponential integrators for stochastic Schrödinger equations

We present a class of exponential integrators to compute solutions of the stochastic Schrödinger equations arising from the modeling of open quantum systems. To be able to implement the methods within the same framework as the deterministic counterpart, we express the solution using Kunita's representation. With appropriate truncations, the solution operator can be written as matrix exponentials, which can be efficiently implemented by the Krylov subspace projection. The accuracy is examined in terms of the strong convergence by comparing trajectories, and in terms of the weak convergence by comparing the density-matrix operators. We show that the local accuracy can be further improved by introducing third-order commutators in the exponential. The effectiveness of the proposed methods is tested using the example from Di Ventra et al. [J. Phys.: Condens. Matter 16, 8025 (2004)JCOMEL0953-898410.1088/0953-8984/16/45/024].

IBM Q Experience as a versatile experimental testbed for simulating open quantum systems

The advent of noisy intermediate-scale quantum (NISQ) technology is changing rapidly the landscape and modality of research in quantum physics. NISQ devices, such as the IBM Q Experience, have very recently proven their capability as experimental platforms accessible to everyone around the globe. Until now, IBM Q Experience processors have mostly been used for quantum computation and simulation of closed systems. Here, we show that these devices are also able to implement a great variety of paradigmatic open quantum systems models, hence providing a robust and flexible testbed for open quantum systems theory. During the last decade an increasing number of experiments have successfully tackled the task of simulating open quantum systems in different platforms, from linear optics to trapped ions, from nuclear magnetic resonance (NMR) to cavity quantum electrodynamics. Generally, each individual experiment demonstrates a specific open quantum system model, or at most a specific class. Our main result is to prove the great versatility of the IBM Q Experience processors. Indeed, we experimentally implement one and two-qubit open quantum systems, both unital and non-unital dynamics, Markovian and non-Markovian evolutions. Moreover, we realise proof-of-principle reservoir engineering for entangled state generation, demonstrate collisional models, and verify revivals of quantum channel capacity and extractable work, caused by memory effects. All these results are obtained using IBM Q Experience processors publicly available and remotely accessible online.

A Meta-summarization of Qualitative Findings About Health Systems Performance Evaluation Models: Conceptual Problems and Comparability Limitations.

Due to the replacement of the issue of performance measurement in health policies worldwide this study identifies and analyzes the models for evaluating health systems performance. For this purpose, a systematic review of the literature on the topic “health systems performance evaluation” is done, making it compatible with a qualitative meta-synthesis of the type “meta-summarization.” It works with all databases related to the theme (PubMed, Scopus, EMBASE, PubAdm and Lilacs/Scielo). Portuguese, English, and Spanish are elected as language limit. Of the total number of articles (n = 32), 23 articles (71.8%) do not have a definition on “performance.” In those who have a definition, “performance” could be summed up in 6 central ideas. Among the most frequent subsidiary concepts that makes up the performance idea are the concepts of “efficiency” (11.9%), “quality” (9.5%) and “effectiveness” (7.1%). Six models were found in this review: “dashboard,” “balanced scorecard,” “open system model,” “PCATool,” “analyze dimension and performance indicators” and “standardized checklist and interview.” The “dashboard” was the most frequent performance evaluation model, found in 35.7% of studies. Only 25% of the reviewed studies presented the performance evaluation model applied specifically to health systems. Far from being configured as management tools useful to comprehension of health systems, these performance evaluation models have shortcomings that compromise their systemic evaluative power. This reinforces the inversion of reality in the relationship between quality and performance. Also, the performance evaluation models used try to adapt to the object, however in most them with relevant analytical problems compromising the specificities in depth of the health system under analysis. This generates inaccuracies and replaces the question about its use and their limitations to compare health systems.

Zn Isotope Composition in the Water Column of the Northwestern Pacific Ocean: The Importance of External Sources

AbstractWe determined Zn isotope composition (δ66Zn) in the water column of the Northwestern Pacific Ocean (NWPO) and its marginal seas to investigate the processes driving vertical and spatial variations. Comparable to previous studies, dissolved δ66Zn was relatively low in the top 200 m, ranging from −0.91 to +0.24‰ and increased with depth toward an averaged value, +0.38±0.10‰, in deep water. We found that δ66Zn observed in the deep water of the NWPO was much lower than the Northeastern Pacific Ocean. Box model approaches suggest that spatial variations in the deep water may be attributed to isotopically light Zn originating from sedimentary input or anthropogenic aerosols. In the surface water, the fractionation factors derived from both closed or open system fractionation models are all less than one in the NWPO. However, both closed and open system models show a relatively poor fit to the measured data. We thus propose that external input is a major factor causing the variations of [Zn] and δ66Zn values in surface water, in addition to the effects of scavenging, physical mixing, and biological uptake. As elevated [Zn] and relatively light δ66Zn in the surface water were observed in high aerosol input regions, aerosol deposition may play a dominant role in regulating Zn elemental and isotopic composition in the surface ocean.

Assessing the Effect of Patterned Breathing Techniques for Reducing Pain during Active Stage of Labour among Pregnant Women in Tertiary Care Hospital, Bhubaneswar

A study was undertaken to evaluate the effect of patterned breathing techniques in reducing pain during active stage of labour among pregnant women in tertiary care hospital, Bhubaneswar (Odisha). The conceptual framework adopted for this study was based on JW Kenny Open System Model. A randomised control trial design was used and consecutive sampling technique was used to select 50 pregnant mothers. Patterned breathing exercises were taught and practised individually to the mothers of experimental group during latent stage of labour and the mothers with 4 cm cervical dilatation were made to practice breathing exercise at each contraction for 1 hour. Pain intensity level was assessed in ve subsequent observations at an interval of 1 hour both in experimental and control group using modi ed numeric pain intensity scale. Five post-tests scores after intervention were recorded using numeric pain intensity scale for assessing pain level after pre-test during the contraction. Findings revealed that in experimental group 80 percent people experienced mild pain and 20 percent experienced moderate pain. As p value was<0.005, so there was signi cant difference between the mean scores of two groups. Thus, patterned breathing techniques have signi cant effect in reducing of labour pain during active stage of labour. But demographic variables do not have signi cant association with the level of pain with patterned breathing exercises.

On the dynamic allocation of assets subject to failure

Motivated by situations arising in surveillance, search and monitoring, in this paper we study dynamic allocation of assets which tend to fail, requiring replenishment before once again being available for operation on one of the available tasks. We cast the problem as a closed-system continuous-time Markov decision process with impulsive controls, maximising the long-term time-average sum of per-task reward rates. We then formulate an open-system continuous-time approximative model, whose Lagrangian relaxation yields a decomposition (innovatively extending the restless bandits approach), from which we derive the corresponding Whittle index. We propose two ways of adapting the Whittle index derived from the open-system model to the original closed-system model, a naïve one and a cleverly modified one. We carry out extensive numerical performance evaluation of the original closed-system model, which indicates that the cleverly modified Whittle index rule is nearly optimal, being within 1.6% (0.4%, 0.0%) of the optimal reward rate 75% (50%, 25%) of the time, and significantly superior to uniformly random allocation which is within 22.0% (16.2%, 10.7%) of the optimal reward rate. Our numerical results also suggest that the Whittle index must be cleverly modified when adapting it from the open-system, as the naïve Whittle index rule is not superior to a myopic greedy policy.

Geometric decoherence in diffusive open quantum systems

Based on a generic quantum open system model, we study the geometric nature of decoherence by defining a complex-valued geometric phase through stochastic pure states describing non-unitary, non-cyclic and non-adiabatic evolutions. The ensemble average of the complex geometric phases for the pure stochastic states yields a conventional geometric phase together with an amplitude factor. We show that the decoherence process described by the decaying amplitude can be a geometric quantity independent of the system's dynamics. It is a remarkable fact that the geometric phase of a quantum system can serve as an ideal realisation of quantum gates due to its robustness against dynamical errors, however, in this paper we show that, for some open quantum systems, a desirable geometric phase may be accompanied by an unwanted robust geometric decoherence factor. Two exactly solvable models are studied to demonstrate that, while the decoherence is a purely dynamical effect for a dephasing two-level model, the decoherence in a dissipative two-level model can be a geometric process. Finally, we show that such a geometric decoherence effect may be eliminated by a non-perturbative control scheme.

Open Systems Pharmacology Community-An Open Access, Open Source, Open Science Approach to Modeling and Simulation in Pharmaceutical Sciences.

Systems pharmacology integrates structural biological and pharmacological knowledge and experimental data, enabling dissection of organism and drug properties and providing excellent predictivity. ...

Equifinality and Flux Mapping: A New Approach to Model Evaluation and Process Representation Under Uncertainty

AbstractUncertainty analysis is an integral part of any scientific modeling, particularly within the domain of hydrological sciences given the various types and sources of uncertainty. At the center of uncertainty rests the concept of equifinality, that is, reaching a given endpoint (finality) through different pathways. The operational definition of equifinality in hydrological modeling is that various model structures and/or parameter sets (i.e., equal pathways) are equally capable of reproducing a similar (not necessarily identical) hydrological outcome (i.e., finality). Here we argue that there is more to model equifinality than model structures/parameters, that is, other model components can give rise to model equifinality and/or could be used to explore equifinality within model space. We identified six facets of model equifinality, namely, model structure, parameters, performance metrics, initial and boundary conditions, inputs, and internal fluxes. Focusing on model internal fluxes, we developed a methodology called flux mapping that has fundamental implications in understanding and evaluating model process representation within the paradigm of multiple working hypotheses. To illustrate this, we examine the equifinality of runoff fluxes of a conceptual rainfall‐runoff model for a number of different Australian catchments. We demonstrate how flux maps can give new insights into the model behavior that cannot be captured by conventional model evaluation methods. We discuss the advantages of flux space, as a subspace of the model space not usually examined, over parameter space. We further discuss the utility of flux mapping in hypothesis generation and testing, extendable to any field of scientific modeling of open complex systems under uncertainty.

HUMAS SEBAGAI FASILITATOR KOMUNIKASI DALAM MENANGANI KELUHAN PELANGGAN WILAYAH SIDOARJO TERKAIT DITARIKNYA SUBSIDI LISTRIK 900 VA

The state electricity company is a state-owned enterprise engaged in the field of electricity. The state electricity company that deals with customer service, namely the distribution section. The state electricity company is an electricity industry that has the potential for people's lives. PT. The Sidoarjo regional electricity company is one of the state electricity companies engaged in the distribution of electricity for customer service management and electricity network services. However, recently there were customer complaints regarding the withdrawal of 900 VA electricity subsidies, this withdrawal was due to policies from the government which were considered to be inadequate to obtain electricity subsidies. Teratric researchers to examine this research because the case experienced just happened and the researchers wanted to know how the process carried out by PR in completing the case. From the study, it was adjusted the results that the poorer communities could still get electricity subsidies by submitting a certificate of incapacity from the kelurahan. This research method uses a qualitative approach and uses descriptive types of research. The literature review used is a functional approach using an open system model with a "two-way symmetrical" approach from the results of this study that public relations succeeded in carrying out its role as a communication facilitator.Keywords: Communication Facilitators, Public relations, Customer

Geochemical evolution of the Quaternary Chachimbiro Volcanic Complex (frontal volcanic arc of Ecuador)

The Chachimbiro volcanic complex (CVC) is a composite volcano located in the frontal part of the Ecuadorian Quaternary Arc.Four periods of activity can be differentiated in Chachimbiro ∼400 ka-long volcanic history, named CH1 (405.7 ± 20.0–298.6 ± 32.9 ka), CH2 (121.75 ± 23.2–36.08 ± 2.8 ka), CH3 (36080 ± 280–22730 ± 120 ybp) and CH4 (5.760 ± 30 ybp) respectively. The magmatic suite ranges in composition from andesites to rhyodacites, and displays systematic increases of SiO2, Sr/Y, La/Yb, incompatible elements (e.g., LREE, MREE, LILE) and depletion of HREE with time. These geochemical features, coupled with radiogenic isotope data and textural observations (e.g., several resorption and overgrowth cycles in plagioclase phenocrysts), suggest an open system evolution for CVC including typical crustal magmatic processes such as recharge, assimilation and fractional crystallisation.To better constrain the magmatic crustal processes of the CVC, we use a multi-model approach including three open system models: RFC (Recharge, Fractional Crystallisation), AFC (Assimilation, Fractional Crystallisation), and EC-RAFC (Energy Constrained – Recharge Assimilation, Fractional Crystallisation). Different simulations have been developed to best fit CVC’s geochemistry (including trace elements, Sr/Y ratios and Sr isotopes), which suggest predominant fractional crystallisation and variable assimilation as the main processes explaining the bulk of the geochemical data of CVC. This is consistent with an overall thermal decline of the magmatic system through time.The genetic model here presented involves the input of a magmatic recharge component matured in the low-mid crust through dominant fractionation of amphibole (±garnet), into intermediate crustal reservoir(s) where magma undergoes extensive FC.

Constraints on Archean crust formation from open system models of Earth evolution

Establishing the mode and rate of formation of the continental crust is crucial for quantifying mass exchange between Earth’s crust and mantle. The limited crustal rock record, particularly of early Archean rocks, has led to a variety of different models of continental growth. Here, we present an open-system model of silicate Earth evolution incorporating the Sm-Nd and Lu-Hf isotope systematics with the aim to constrain crustal growth during the Archean and its effect on the chemical and isotopic evolution of Earth’s crust-mantle system. Our model comprises four reservoirs: the bulk continental crust (CC), depleted upper mantle (UM), lower mantle (LM), and an isolated reservoir (IR) where recycled crust is stored transiently before being mixed with the LM. The changing abundance of isotope species in each reservoir is quantified using a series of first order linear differential equations that are solved numerically using the fourth order Runge–Kutta method at 1 Myr time steps for 4.56 Gyr (the age of the Earth). The model results show that only continuous and exponential crustal growth reproduces the present-day abundances and isotope ratios in the terrestrial reservoirs. Our preferred crustal growth model suggests that the mass of the CC by the end of Hadean (4.0 Ga) and end of Archean (2.5 Ga) was ∼30% and ∼75% of the present-day mass of the CC, respectively. Models proposing formation of most (∼90%) of the present-day CC during the initial 1 Gyr or nearly 50–60% during the last 1 Gyr are least favorable. Significant mass exchange between crust and mantle, that is, both the formation and recycling of crust, started in the Hadean with Sm-Nd and Lu-Hf isotope evolution typical for mafic rocks. Depletion of the UM (in incompatible elements) during the early Archean is mitigated by the input of recycled crust, so that the UM maintained a near-primitive Hf-Nd isotope composition. The LM also retained a near-primitive Hf-Nd isotope composition during the Archean, but for different reasons. In contrast to the UM, the crustal return flux into the LM is transiently stored (∼ 1 Gyr) in an isolated reservoir (IR), which limits the mass flux into and out of the LM. The IR in our model is distinct from other mantle reservoirs and possibly related to stable crustal blocks or, alternatively, to recycled crust in the mantle that remains temporarily isolated, perhaps at the core-mantle boundary (LLSVPs).

Leading change for survival: The rural flexi-school approach

This article seeks to present the perspectives of three school leaders in one rural primary school in the English East Midlands, who, when faced with closure due to a falling student numbers, decided to offer and operate a flexi-schooling model of educational provision. We aim to find out, through a theoretical model of systems school leadership, how the school leadership team addressed this issue. Findings suggest that the principles of systems leadership, operating through an open systems model, have facilitated the journey towards flexi-schooling and ensured the survival and growth of the school. The learning community created with parents and the personalisation of the curriculum for learners reflects an innovative curriculum design and in part solves the problems which led to the initial decision taken by parents to home-educate. Focusing on ways to secure healthy student numbers, school leaders developed a partnership with a multi-academy trust, yet they still face challenges in formally recording student numbers when their attendance is only part of the week.

Multiple-scale perturbation method on integro-differential equations: Application to continuous-time quantum walks on regular networks in non-Markovian reservoirs

Non-Markovianity may significantly speed up quantum dynamics when the system interacts strongly with an infinite large reservoir, of which the coupling spectrum should be fine-tuned. The potential benefits are evident in many dynamics schemes, especially the continuous-time quantum walk. Difficulty exists, however, in producing closed-form solutions with controllable accuracy against the complexity of memory kernels. Here, we introduce a new multiple-scale perturbation method that works on integro-differential equations for general study of memory effects in dynamical systems. We propose an open-system model in which a continuous-time quantum walk is enclosed in a non-Markovian reservoir, that naturally corresponds to an error correction algorithm scheme. By applying the multiple-scale method we show how emergence of different time scales is related to transition of system dynamics into the non-Markovian regime. We find that up to two long-term modes and two short-term modes exist in regular networks, limited by their intrinsic symmetries. In addition to the effective approximation by our perturbation method on general forms of reservoirs, the speed-up of quantum walks assisted by non-Markovianity is also confirmed, revealing the advantage of reservoir engineering in designing time-sensitive quantum algorithms.

Building Networks to Harness Innovation Synergies: Towards an Open Systems Approach to Sustainable Development

Open innovation has become a popular approach, especially since 2003, as people began purposively managing, evolving and harnessing knowledge flows across organizational boundaries but through increasing connections with systemic knowledge nodes relevant to the innovation process. The creation and appropriation of such knowledge has evolved rapidly with digitalization and the proliferation of broadband networks. Individuals, firms and organizations now connect and coordinate to support innovations openly across innovation systems. This paper proposes an open systems model with institutional underpinnings to not only quicken knowledge flows and expand the networks to a wider range of socioeconomic agents, but also for their inclusive participation in shaping the processes of achieving sustainable development through environmental greening and egalitarian balancing of society. In doing so, using examples, the paper focuses on developments since Schumpeter’s ground-breaking exposition of innovation to explain how individuals, firms, farms and organizations can participate actively in open innovation networks to connect productively with the critical knowledge nodes in society.

Quantum system-bath dynamics with quantum superposition sampling and coupled generalized coherent states

Previously, we introduced two versions of the Multiconfigurational Ehrenfest (MCE) approach to high dimensional quantum dynamics. It has been shown that the first version, MCEv1, converges well to the existing benchmarks for high dimensional model systems. At the same time, it was found that the second version, MCEv2, had more difficulty converging in some regimes. As MCEv2 is particularly suited for direct dynamics, it is important to facilitate its convergence. This paper investigates an efficient method of basis set sampling, called Quantum Superposition Sampling (QSS), which dramatically improves the performance of the MCEv2 approach. QSS is tested on the spin-boson model, often used for modeling of open quantum systems. It is also shown that the quantum subsystem in the spin-boson model can be conveniently treated with the help of two level system coherent states. Generalized coherent states, which combine two level system coherent states for the description of the system and Gaussian coherent states for description of the bath, are introduced. Various forms of quantum equations of motion in the basis of generalized coherent states can be developed by analogy with known quantum dynamics equations in the basis of Gaussian coherent states; in particular, the multiconfigurational Ehrenfest method becomes a version of coupled generalized coherent states, and QSS can then be viewed as a generalization of a sampling method known for the existing coupled coherent states method which uses Gaussian coherent states.

Toward Agentic HRD: A Translational Model of Albert Bandura’s Human Agency Theory

The ProblemAlbert Bandura has refined a theory of human agency with three modes and four core properties within social cognitive theory. Human agency plays a critical role in one’s adaptation, self-development, and self-renewal. Despite its relevance to human resource development (HRD), human agency theory has not been explored or effectively utilized in HRD research and practice.The SolutionFollowing Bandura’s human agency theory, a translational and implementational model for HRD was proposed. First, the model integrated the four core properties of human agency (intentionality, forethought, self-reactiveness, and self-reflectiveness) into a model by altering the sequence to align with major HRD processes. Second, it synthesized triadic reciprocal determinism with the four core properties of human agency by placing the agent at the center of the model. Third, it is an open systems model that describes reciprocal determinism between the agent and the environment at micro, meso, and macro levels, indicating the dynamics of personal, proxy, and collective agency.The StakeholdersThe model will be useful for career practitioners, coaches, organization development consultants, and other HRD professionals who deliver interventions. HRD researchers and theorists may find it worthwhile to test and validate the model. In addition, regardless of disciplines, researchers, and practitioners who follow social cognitive theory may find some insights from the translational model.

Leading change for success: embracing resistance

Purpose Organizational change is one of the most researched issues in management and leadership. Change is generally viewed as necessary, with positive outcomes for all stakeholders. Resistance is consequently seen as a surprising outcome. However, much of the management literature focuses on change as organizational dynamics-driven, especially by those at the top, in the interests of those at the top, often with scant attention to the role of employees. The purpose of this paper is to take a different perspective, grounded in the systems theory. Design/methodology/approach This is a conceptual paper. The authors critically examine theoretical explanations of resistance to change in organizations and offer an alternative perspective. Findings Systems theorists have addressed change, and its necessity in organizational survival, using an open systems model. The open systems theory posits that organizations are social systems that have purposes of their own and is made of parts (employees) that are purposeful and operate within a purposeful larger system – the environment (stakeholders). Change that ignores a key part – employees – will be resisted. Originality/value Using the systems theory, the authors propose several suggestions for organizational leaders and managers to implement sustainable change. These include, among others, recommendations on circular organizational designs, the need for more democratic organizations, purposeful leadership styles and how to include employees in proactive organizational change processes.

A quantum open system model of molecular battery charged by excitons.

The analytically tractable model employing quantum Markovian master equations, derived by a weak coupling procedure and generating completely positive dynamics is proposed to describe a model of a molecular battery charged by a nonequilibrium excitonic reservoir. Excitons are produced by nonequilibrium processes involving, e.g., light absorption and chemical reactions. Various relations concerning the efficiency of the involved processes of energy transfer and the stability of the battery are discussed. The model can be treated as an initial step in applications of a mathematically sound version of quantum theory of open systems to complex processes of energy transfer in biological systems and man-made devices based on organic materials.

The limits of transparency: A systems theory view

AbstractThe paper explores the implications of Ludwig von Bertalanffy's general systems theory for the current debates on the nature of organizational transparency as an element of good governance. If transparency implies the exchange of information, then it may be taken, at a metaphorical level, to constitute a dimension of metabolism theorized by Bertalanffy's open systems model. Yet, the model likewise lays bare some of the limits of transparency idea. Bertalanffy's work on the nature of emergent properties, his critique of the stimulus–response scheme, and his perspectivistic account of the systemic perception of the environment all point in the direction of the impossibility of full transparency. Later systems‐theoretic work on operational closure and self‐referentiality has reinforced and even radicalized these insights, which are shown to resonate with some of the key arguments in the contemporary economics, sociology of knowledge, and business ethics.