Input Control Strategy Research Articles

QPJVis Demo: Quality-Boost Progressive Join Query Processing System

Progressive query processing enables data scientists to efficiently analyze and explore large datasets. Data scientists can start further analyses earlier if the progressive result can represent the complete results well. Most progressive processing frameworks carefully control which parts of the input to process in order to improve the quality of progressive results. The input control strategies work well when the data are processed uniformly. However, the progressive results will be biased towards the join keys if the processed data are not uniform. A recently proposed input&output framework named QPJ corrects the bias by temporarily hiding some results. The framework dynamically estimates the distribution of the complete result and outputs progressive results with a similar distribution to the estimated complete result. This demo presents QPJVis, which is a progressive query processing system designed to inherently process the progressive queries using the QPJ framework. Additionally, we also implement an input control framework, Prism, in QPJVis so that users can compare the difference between the input&output framework and a purely input framework.

Honey bee-associated bacteria as producers of bioactive compounds for protecting hives. A biosynthetic gene-based approach

Honey bee-associated bacteria are a source of natural compounds of interest for controlling hive decline which is threatening bee health globally. Genes involved in the biosynthesis of a series of extracellular compounds released by bacteria living on the external surface of honey bees were investigated. A biosynthetic gene-based approach was adopted by developing a battery of primers to target the genes involved in the biosynthesis of four groups of bioactive compounds (pyrrolizidine alkaloids, surfactin, 2-heptanone and helveticin J). The primers were tested on 51 bacterial isolates belonging to Bacillus thuringiensis, Acetobacteraceae bacterium, Bifidobacterium asteroides and Apilactobacillus kunkeei. The developed primers led to species-specific detection and characterization of the functional genes involved in the production of three out of four groups of compounds selected for this study. The findings suggest that microbial populations inhabiting apiaries harbor genes involved in the biosynthesis of metabolites linked to the reduction of important honey bee pathogens such as Varroa destructor, Paenibacillus larvae and Nosema ceranae. The gene-based approach adopted for evaluating the biosynthetic potential of bioactive compounds in hives is promising for investigating further compounds for low input control strategies of bee enemies.

A methodology employing retention modeling for achieving control space in liquid chromatography method development using quality by design approach

This study reports the application of retention modeling and quality by design practices for reverse-phase liquid chromatographic method development of a new chemical entity. Prior to the retention modeling, preliminary screening experiments were performed for the selection of stationary phase, organic modifiers, and method parameters. Based on the results of preliminary method conditions, tG-T (gradient time - temperature) 2-D modeling with 4 input runs, and tG-T-tc (gradient time-temperature-ternary composition) 3-D modeling with 12 input runs were designed to build a model for achieving the optimized separation. Modeling of reverse phase separations was based on the measurement of both retention times and peak areas. A design space with appropriate input variables and control strategy was established prior to optimization and robustness evaluation following the quality by design framework. DryLabⓇ was used to predict the optimized gradient profile and separation temperature. The robustness evaluation was carried out using the multiple factors at a time approach and the control space was established. The interdependence of control space and the control strategy was demonstrated by evaluating method robustness using two levels of system suitability criteria. The predictive accuracy of the retention modeling was established through experimental verification of the in-silico predictions. The quality by design based method development approach demonstrated the in-silico optimization as an integral component of reverse-phase chromatographic method development to evaluate the interplay of factors such as organic modifiers, separation temperature and gradient time, which greatly integrated and enhanced method robustness during method development.

Analysis and design of an integrated RF energy harvester for ultra low‐power environments

SummaryRadio‐frequency (RF) energy harvesting must cope with the limited availability and high variability of the energy source. In this paper, the available RF power in three typical environments (urban, semi‐urban, and rural) is investigated. Measurements show that in the surveyed urban and semi‐urban environments, an average input power above −22 and −29 dBm, respectively, is available in the [700, 1,000] MHz band.A mathematical model of the interface between the RF rectifier and the DC‐DC converter is provided. The analysis demonstrates that the energy can be efficiently transferred to the external accumulator coupling the rectifier with a strobed, input control DC‐DC converter.Based on the measurements and the analysis, an RF harvester architecture has been designed in 65 nm Complementary Metal‐Oxide Semiconductor (CMOS) technology to operate over the [−40, 85]oC temperature and the [1.1, 2.5] V battery voltage ranges. The input control strategy adopted for the converter allows the adaptation of the harvester to the available RF power and enables a real maximum power point tracking (MPPT).Post‐layout simulation of the harvester, recharging a large capacitor, precharged at 2 V, at 950 MHz of input frequency returned a 33.4% peak efficiency with an input power of 15 μW (−18 dBm). The minimum input power leading to a positive energy balance is −30 dBm with an output voltage of 1.1 V.

Coupling stable isotopes and water chemistry to assess the role of hydrological and biogeochemical processes on riverine nitrogen sources

Accurate source identification is critical for optimizing water pollution control strategies. Although the dual stable isotope (15N-NO3-/18O-NO3-) approach has been widely applied for differentiating riverine nitrogen (N) sources, the relatively short-term (<1 yr) 15N-NO3-/18O-NO3- records typically used in previous studies often hinders rigorous assessment due to high temporal variability associated with watershed N dynamics. Estimated contributions of legacy N sources in soils and groundwater to riverine N export by modeling approaches in many previous studies also lack validation from complementary information, such as multiple stable isotopes. This study integrated three years of multiple stable isotope (15N-NO3-/18O-NO3- and 2H-H2O/18O-H2O) and hydrochemistry measurements for river water, groundwater and rainfall to elucidate N dynamics and sources in the Yongan watershed (2474 km2) of eastern China. Nonpoint source N pollution dominated and displayed considerable seasonal and spatial variability in N forms and concentrations. Information from δ15N-NO3- and δ18O-NO3- indicated that riverine N dynamics were regulated by contributing sources, nitrification and denitrification, as well as hydrological processes. For the three examined catchments and entire watershed, slow subsurface and groundwater flows accounted for >75% of river discharge and were likely the major hydrological pathways for N delivery to the river. Riverine NO3− sources varied with dominant land use (p < 0.001), with the highest contributions of groundwater (60%), wastewater (35%), and soil (50%) occurring in agricultural, residential and forest catchments, respectively. For the entire watershed, groundwater (∼50%) and soil N (>30%) were the dominant riverine NO3− sources, implying considerable potential for N pollution legacy effects. Results were consistent with observed nitrous oxide dynamics and N sources identified in previous modeling studies. As the first attempt to apply multiple isotope tracers for exploring and quantifying N transformation and transport pathways, this study provides an integrated approach for verifying and understanding the N pollution legacy effects observed in many watersheds worldwide. This study highlights that river N pollution control in many watersheds requires particular attention to groundwater restoration and soil N management in addition to N input control strategies.

Multiple input control strategies for robust and adaptive climate engineering in a low-order 3-box model.

A low-order 3-box energy balance model for the climate system is employed with a multivariable control scheme for the evaluation of new robust and adaptive climate engineering strategies using solar radiation management. The climate engineering measures are deployed in three boxes thus representing northern, southern and central bands. It is shown that, through heat transport between the boxes, it is possible to effect a degree of latitudinal control through the reduction of insolation. The approach employed consists of a closed-loop system with an adaptive controller, where the required control intervention is estimated under the RCP4.5 radiative scenario. Through the online estimation of the controller parameters, adaptive control can overcome key issues related to uncertainties of the climate model, the external radiative forcing and the dynamics of the actuator used. In fact, the use of adaptive control offers a robust means of dealing with unforeseeable abrupt perturbations, as well as the parametrization of the model considered, to counteract the RCP4.5 scenario, while still providing bounds on stability and control performance. Moreover, applying multivariable control theory also allows the formal controllability and observability of the system to be investigated in order to identify all feasible control strategies.

Line Balancing Strategy for Re-Entrant Manufacturing

Scheduling in a re-entrant manufacturing environment is a complex task that requires a scheduler to handle a larger number of uncertainties than in a traditional manufacturing environment. Many input control strategies and dispatching rules are applied to re-entrant processes to achieve fast and relatively effective solutions. However, due to the complexity of these processes, the dispatching rules currently employed in general flow shops do not guarantee the consistency of results despite the benefits of these rules. To address this issue, an extremely robust drum-buffer-rope-based releasing and holding scheduling method is proposed in this paper. An overview of the proposed method is presented, including the process by which the re-entrant process is reconfigured into independent flow shops and the balancing of the production loads among individual loops. Nine scheduling scenarios comprising different combinations of three loop load measurement parameters and three loop-balancing methods are employed to test the applicability and performance of the proposed method.

Material-handling-system-based input control policy for wafer fabrication

In this paper, a new input control strategy is proposed for wafer fabrication facilities. This strategy is an adaptation of workload regulating and CONWIP, and comprises of two sequential steps: 1) determination of operational lot sizes; 2) release of lots based on a material handling system-based CONLOAD approach. We show the superiority of our strategy over a CONWIP-based policy via simulation of a real-life wafer fab. An approach for determining target workload levels for the proposed strategy is also presented.

Material-handling-system-based input control policy for wafer fabrication

In this paper, a new input control strategy is proposed for wafer fabrication facilities. This strategy is an adaptation of workload regulating and CONWIP, and comprises of two sequential steps: 1) determination of operational lot sizes; 2) release of lots based on a material handling system-based CONLOAD approach. We show the superiority of our strategy over a CONWIP-based policy via simulation of a real-life wafer fab. An approach for determining target workload levels for the proposed strategy is also presented.

Feedback Control Strategy to Eliminate the Input Current Harmonics of Matrix Converter Under Unbalanced Input Voltages

It is generally considered that feedback control of input currents in the matrix converter (MC) is hard to be realized due to the coupling of input control and output control, which reduces the degree of freedom and robustness. Moreover, under unbalanced input voltages, the coupling also results in severe distortion of input currents when the commonly used feedforward compensation control method with fixed input power factor is adopted. To address these two issues, this paper proposes a feedback control strategy on the input side of MC. This strategy is based on a control method which can modify input reference currents. The input control strategy is embedded into the output control strategy and thus is the inner loop of the system control. The input-side controllers can be designed to achieve expected input control objectives and maintain the output performance at the same time. On this basis, resonant controllers are applied to regulate input currents and instantaneous active power, so as to directly eliminate the input current harmonics and meanwhile ensure the load absorbing constant active power under unbalanced input voltages. The validity and feasibility of the proposed strategy are verified by the simulation and experimental results.

一类水体富营养化复杂动力系统构建及其动力学分析

基于吴家园水库水体富营养化研究进程，本论文在动态建模过程中引入分布式函数来刻画总磷输入随季度变化的特征，构建了一类水体富营养化复杂动力系统，对所建系统进行了一定的理论分析与数值模拟，建立了该系统内平衡点渐近稳定的判断准则，模拟出总磷浓度和藻类种群密度动态变化趋势，剖析出总磷与藻类种群之间的相互作用机制，进而揭示总磷输入可控策略对水体富营养化状况和藻类水华的影响作用机理。这些研究工作为进一步预测吴家园水库营养盐动态演化趋势和探索吴家园水库藻类种群生长动态规律提供了一定的理论基础。 In this paper, firstly, on the basis of research progress of water eutrophication in Wujiayuan res-ervoir, a distributed function is introduced to characterize the total phosphorus input being changed with the season in the process of dynamic modeling, a water eutrophication complex dy-namical system has been structured. Secondly, some theoretical analysis and numerical simulation on the complex dynamical system have been investigated to establish some judgment criterions for the asymptotic stability of the internal equilibrium point and describe the dynamic trends of total phosphorus concentration and algal population density, which can dissect the interaction mechanism between total phosphorus and algal population, and then reveal the influence mecha-nism of total phosphorus input control strategy on eutrophication status and algal bloom. Finally, these studies can provide certain theoretical basis for the further prediction of the nutrient dy-namic evolution trend and the deep exploration of the algae population growth dynamic law in Wujiayuan reservoir.

Backstepping stabilization of the linearized Saint-Venant–Exner model

Using backstepping design, exponential stabilization of the linearized Saint-Venant–Exner (SVE) model of water dynamics in a sediment-filled canal with arbitrary values of canal bottom slope, friction, porosity, and water–sediment interaction, is achieved. The linearized SVE model consists of two rightward convecting transport Partial Differential Equations (PDEs) and one leftward convecting transport PDE. A single boundary input control strategy with actuation located only at the downstream gate is employed. A full state feedback controller is designed which guarantees exponential stability of the desired setpoint of the resulting closed-loop system. Using the reconstruction of the distributed state through a backstepping observer, an output feedback controller is established, resulting in the exponential stability of the closed-loop system at the desired setpoint. The proposed state and output feedback controllers can deal with both subcritical and supercritical flow regimes without any restrictive conditions.

Application of high-throughput mini-bioreactor system for systematic scale-down modeling, process characterization, and control strategy development.

High-throughput systems and processes have typically been targeted for process development and optimization in the bioprocessing industry. For process characterization, bench scale bioreactors have been the system of choice. Due to the need for performing different process conditions for multiple process parameters, the process characterization studies typically span several months and are considered time and resource intensive. In this study, we have shown the application of a high-throughput mini-bioreactor system viz. the Advanced Microscale Bioreactor (ambr15(TM) ), to perform process characterization in less than a month and develop an input control strategy. As a pre-requisite to process characterization, a scale-down model was first developed in the ambr system (15 mL) using statistical multivariate analysis techniques that showed comparability with both manufacturing scale (15,000 L) and bench scale (5 L). Volumetric sparge rates were matched between ambr and manufacturing scale, and the ambr process matched the pCO2 profiles as well as several other process and product quality parameters. The scale-down model was used to perform the process characterization DoE study and product quality results were generated. Upon comparison with DoE data from the bench scale bioreactors, similar effects of process parameters on process yield and product quality were identified between the two systems. We used the ambr data for setting action limits for the critical controlled parameters (CCPs), which were comparable to those from bench scale bioreactor data. In other words, the current work shows that the ambr15(TM) system is capable of replacing the bench scale bioreactor system for routine process development and process characterization.

The Use of Servo-Constraints in the Inverse Dynamics Analysis of Underactuated Multibody Systems

Underactuated mechanical systems have fewer control inputs than degrees of freedom. The specified in time outputs, equal in number to the number of inputs, lead to servo-constraints on the system. The servo-constraint problem is then a specific inverse simulation problem in which an input control strategy (feedforward control) that forces an underactuated system to complete the partly specified motion is determined. Since mechanical systems may be “underactuated” in several ways, and the control forces may be arbitrarily oriented with respect to the servo-constraint manifold, this is, in general, a challenging task. The use of servo-constraints in the inverse dynamics analysis of underactuated systems is discussed here with an emphasis on diverse possible ways of the constraint realization. A formulation of the servo-constraint problem in configuration coordinates is compared with a setting in which the actuated coordinates are replaced with the outputs. The governing equations can then be set either as ordinary differential equations (ODEs) or differential-algebraic equations (DAEs). The existence and nonexistence of an explicit solution to the servo-constraint problem is further discussed, related to so-called flat systems (with no internal dynamics) and nonflat systems (with internal dynamics). In case of nonflat systems, of paramount importance is stability of the internal dynamics. Simple case studies are reported to illustrate the discussion and formulations.

Entropy-based stabilizing feedback law under input constraints of a CSTR

The paper deals with nonlinear control under input constraints of a non isothermal Continuous Stirred Tank Reactor (CSTR) using thermodynamic concepts. More precisely, the paper presents an extension of the previous work (Hoang et al. (2012)) where the jacket temperature is used as the only control input. Constrained input control strategy is based on the observation that the chemical reactor operates at an unique stationary temperature when the lower or upper bound of the input variable is imposed. This control design results in a global asymptotic stabilizing feedback law that provides a locally exponentially stable behaviour of the overall system.

Diversity of Servo-Constraint Problems for Underactuated Mechanical Systems: A Case Study Illustration

Underactuated mechanical systems are systems with fewer control inputs than degrees of freedom. Determination of an input control strategy that forces an underactuated system to complete specified in time outputs (servo-constraints), whose number is equal to the number of inputs, can be a challenging task. Diversity of the servo-constraint problems is discussed here using a simple spring-mass system mounted on a carriage (two degrees of freedom, one control input, and one specified in time output). A formulation of underactuated system dynamics which includes the output coordinates is motivated, with the governing equations arising either as ODEs (ordinary differential equations) or DAEs (differential-algebraic equations). Solutions to the servo-constraint problem are then discussed with reference to so-called non-flat systems (with internal dynamics) and differentially flat systems (no internal dynamics). Some computational issues related to the ODE and DAE formulations are finally discussed, and relevant simulation results for the sample case study are reported.

Inverse dynamics of underactuated mechanical systems: A simple case study and experimental verification

Underactuated systems are featured by fewer control inputs than the degrees-of-freedom, m < n. The determination of an input control strategy that forces such a system to complete a set of m specified motion tasks is a challenging task, and the explicit solution existence is conditioned to differential flatness of the problem. The flatness-based solution denotes that all the 2 n states and m control inputs can be algebraically expressed in terms of the m specified outputs and their time derivatives up to a certain order, which is in practice attainable only for simple systems. In this contribution the problem is posed in a more practical way as a set of index-three differential–algebraic equations, and the solution is obtained numerically. The formulation is then illustrated by a two-degree-of-freedom underactuated system composed of two rotating discs connected by a torsional spring, in which the pre-specified motion of one of the discs is actuated by the torque applied to the other disc, n = 2 and m = 1. Experimental verification of the inverse simulation control methodology is reported.

Dynamics and control of underactuated mechanical systems: analysis and simple experimental verification

AbstractUnderactuated mechanical systems are systems with fewer control inputs than the degrees of freedom, m &lt; n, the relevant technical examples being e.g. cranes, aircrafts and flexible manipulators. The determination of an input control strategy that forces an underactuated system to complete a set of m specified motion tasks (servo‐constraints) is a demanding problem. The solution is conditioned to differential flatness of the problem, denoted that all 2n state variables and m control inputs can algebraically be expressed, at least theoretically, in terms of the desired m outputs and their time derivatives up to a certain order. A more practical formulation, motivated hereafter, is to pose the problem as a set of differential‐algebraic equations, and then obtain the solution numerically. The theoretical considerations are illustrated by a simple two‐degree‐of‐freedom underactuated system composed of two rotating discs connected by a flexible rod (torsional spring), in which the pre‐specified motion of the first disc is actuated by the torque applied to the second disc, n = 2 and m = 1. The determined control strategy is then verified experimentally on a laboratory stand representing the two‐disc system. (© 2009 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Exploring Franchisor Franchisee Relationship: Building a Predictive Model of Franchisee Performance

Although the selection of suitable franchisees has been identified as an important dimension of success of a Franchise Network, the same has been at the best a subjective process. This study is amongst the first studies, in the Indian context, which relates the selection criteria used by the franchisors in the selection of potential franchisees to their behavioural outcomes that the franchisors desire. It also provides direction to use prudent selection criteria as an input control strategy. This study has empirically demonstrated that well-chosen selection criteria can explain a significant component of variance in the franchisee behaviour. Moreover, the study also alludes that the franchisors should be able to identify and select franchisees which are more likely to perceive their relationship with the franchisors to be more cooperative and behave less opportunistically. In fact, the franchisees with favourable dispositions and desirable characteristics can lower the agency costs to the franchisors in the form of less safeguarding and monitoring costs.

The Complexity of Trust-Control Relationships in Creative Organizations: Insights From a Qualitative Analysis of a Conductorless Orchestra

Using a qualitative approach, I study two processes of intra-organizational cooperation and coordination – control and trust – in creative organizations. Specifically, I analyze the complex nature of trust-control relationships in Orpheus orchestra, the world's largest contemporary conductorless orchestra. I discuss how it rehearses and performs without a baton holder and benefits from the creativity of all musicians. This study supports the duality perspective of trust-control relationships. While competence trust and goodwill trust enable musicians to participate in organizational decision-making and be creative, it is behavioral, input, output and social control strategies that facilitate the development of trust and help ensure the orchestra's long-term success. Trust-control duality allows Orpheus to achieve optimal distinctiveness, which aligns creativity and artistic freedoms with the goals of economic stability.