Comparative study of decay ratios of disturbance-rejection magnitude optimum method for PI controllers

One of the key time-domain closed-loop performance requirements is the closed-loop response decay ratio. In this paper, the decay ratios of the disturbance-rejection magnitude optimum (DRMO) tuning method [Vranci? D, Strmcnik S, Kocijan J. Improving disturbance rejection of PI controllers by means of the magnitude optimum method. ISA Trans 2004; 43: 73-84; Vranci? D, Strmcnik S. Achieving optimal disturbance rejection by using the magnitude optimum method. In: Pre-prints of the CSCC'99 conference. 1999. p. 3401-6] are analyzed and compared to decay ratios of two other modern tuning methods, i.e. the Kappa-Tau tuning method (based on time-domain step-response characteristics) [Astr?m KJ, H?gglund T. PID controllers: Theory, design, and tuning. 2nd ed. Instrument Society of America; 1995] and the non-convex optimization tuning method (based on frequency response) [Panagopoulos H, Astr?m KJ, H?gglund T. Design of PI controllers based on non-convex optimization. Automatica 1998; 34: 585-601; Panagopoulos H, Astr?m KJ, H?gglund T. Design of PID controllers based on constrained optimisation. IEE Proc Control Theory Appl 2002; 149 (1): 32-40]. It is shown that the DRMO method results in such a closed-loop response that the decay ratio is within a relatively narrow interval when compared to the other two methods.     

Gaming Prediction Markets: Equilibrium Strategies with a Market Maker

We study the equilibrium behavior of informed traders interacting with market scoring rule (MSR) market makers. One attractive feature of MSR is that it is myopically incentive compatible: it is optimal for traders to report their true beliefs about the likelihood of an event outcome provided that they ignore the impact of their reports on the profit they might garner from future trades. In this paper, we analyze non-myopic strategies and examine what information structures lead to truthful betting by traders. Specifically, we analyze the behavior of risk-neutral traders with incomplete information playing in a dynamic game. We consider finite-stage and infinite-stage game models. For each model, we study the logarithmic market scoring rule (LMSR) with two different information structures: conditionally independent signals and (unconditionally) independent signals. In the finite-stage model, when signals of traders are independent conditional on the state of the world, truthful betting is a Perfect Bayesian Equilibrium (PBE). Moreover, it is the unique Weak Perfect Bayesian Equilibrium (WPBE) of the game. In contrast, when signals of traders are unconditionally independent, truthful betting is not a WPBE. In the infinite-stage model with unconditionally independent signals, there does not exist an equilibrium in which all information is revealed in a finite amount of time. We propose a simple discounted market scoring rule that reduces the opportunity for bluffing strategies. We show that in any WPBE for the infinite-stage market with discounting, the market price converges to the fully-revealing price, and the rate of convergence can be bounded in terms of the discounting parameter. When signals are conditionally independent, truthful betting is the unique WPBE for the infinite-stage market with and without discounting.     

Mobile commerce and device specific perceived risk

This study examines the role of perceived risk and access device type on consumers’ on-line purchase decisions. We use a two-step hurdle approach to estimate consumer behavior. In the first step, the decision of whether to engage in eCommerce is estimated and in the second step, how many orders to place is estimated. We use a large multi-year survey sample of households from Canada’s national statistical agency—Statistics Canada. The sample size is such that we are able to conduct sub-sample analysis of PC-only users, mobile-only users, and other-users. We show that online security and price significantly influence mobile eCommerce. We also show that there is a statistically significant difference in the intensity of eCommerce engagement across device type and consumer risk type (high/low). One of our main findings is that perceived risk affects purchase decisions for mobile users more than PC users, however additional comparisons are carried out with our analysis.     

Fuzzy gain-scheduling control of a gas-liquid separation plant implemented on a PLC

In the paper an approach to the non-linear control of a gas-liquid separation plant is presented. To solve the problem the fuzzy gain-scheduling method was used and implemented on a programmable logic controller (PLC). Velocity-based linearization approach was used for control system design and implementation for the first time in process control application. Emphasis was placed on the appropriate adaptation of the method and some important implementation issues. The algorithm was carefully designed and tested by using ordinary simulation, hardware-in-the-loop simulation, and experiments on the real plant. The results show that the proposed approach substantially improves the closed-loop performance of the plant.     

Evidence that lamprey GnRH-III does not release FSH selectively in cattle

Experiments were performed to test the hypothesis that lamprey GnRH-III (lGnRH-III) selectively releases FSH. Primary cultures of bovine adenohypophyseal cells were treated with mammalian GnRH (mGnRH) and lGnRH-III (10(-9), 10(-8), 10(-7) and 10(-6) M) or control media in Experiment 1. All doses of mGnRH and the two highest doses of lGnRH-III stimulated (P < 0.001) a non-selective release of LH and FSH. In Experiments 2-4, Latin Square designs were utilized in vivo to examine whether physiological and hormonal milieu regulate putative selective effects of lGnRH-III. In Experiments 2 and 3, ovariectomized cows with basal levels of estradiol only (Experiment 2) or in combination with luteal phase levels of progester-one (Experiment 3) were injected with mGnRH and lGnRH-III (0.055, 0.11, 0.165 and 1.1 microg/kg body weight (BW) and saline. All doses of mGnRH released (P < 0.001) LH and FSH, but only the highest dose of lGnRH-III stimulated (P < 0.001) a non-selective release of both LH and FSH (Experiment 3). For Experiments 4A and 4B, intact, mid-luteal phase cows were injected with mGnRH and lGnRH-III (1.1 microg/kg BW; Experiment 4A), lGnRH-III (1.1 and 4.4 microg/kg BW; Experiment 4B) and saline. As before, mGnRH released (P < 0.001) both LH and FSH at all doses. In contrast, lGnRH-III at the highest dose released (P < 0.001) LH but not FSH. These findings suggest that lGnRH-III may act as a weak competitor for the mGnRH receptor and do not support the hypothesis that it selectively releases FSH in cattle.     

The effect of Fe on magnetic moment of electrodeposited CoFe alloys—Experimental study and analytical model

The effect of Fe³⁺ concentration on saturation magnetic flux density (B_s) of electrodeposited Co_40-44Fe_60-56 films was investigated. The results show that if the conditions at the electrochemical interface for nucleation/precipitation of iron(III) hydroxide (Fe(OH)₃) are reached, the B_s of electrodeposited Co_40-44Fe_60-56 films quickly decreases as a result of the Fe(OH)₃ incorporation into deposit. These conditions are discussed as a function of the solution formulation (pH) and the parameters of electrodeposition process (current density, current efficiency, diffusion layer thickness) and a simple analytical model is developed qualitatively describing the hydroxide incorporation phenomenon and resulting decrease in B_s of Co_40-44Fe_60-56 films.     

Reaction kinetics of metal deposition via surface limited red-ox replacement of underpotentially deposited metal monolayers

The study of the kinetics of metal deposition via surface limited red-ox replacement of underpotentially deposited metal monolayers is presented. The model system was Pt submonolayer deposition on Au(1 1 1) via red-ox replacement of Pb and Cu UPD monolayers on Au(1 1 1). The kinetics of a single replacement reaction was studied using the formalism of the comprehensive analytical model developed to fit the open circuit potential transients from deposition experiments. The practical reaction kinetics parameters like reaction half life, reaction order and reaction rate constant are determined and discussed with their relevance to design and control of deposition experiments. The effects of transport limitation and the role of the anions/electrolyte on deposition kinetics are investigated and their significance to design of effective deposition process is discussed.     

Coherence of VCSEL's for holographic interconnects

Temporal and spatial coherence measurements were conducted on the emission from AlGaAs-GaAs vertical-cavity surface-emitting lasers (VCSEL's). Results of both CW and pulsed conditions from devices of 8- and 15-μm diameter are reported. Coherence length of 0.6 mm for multi-mode and ~75 cm for single-mode were obtained. Thermal chirp reduces the single-mode coherence to 16 mm for 5 ns pulses. For holograms smaller than 0.6 mm in size the density of information that can be read by the VCSEL's is diffraction-limited by the size of the holographic element     

Melt granulation in fluidized bed: a comparative study of spray-on versus in situ procedure

Objective: The aim of this study was to investigate the influence of process parameters, binder content and binder addition method on characteristics of the granules obtained by melt granulation (MG) in fluidized bed.

Methods: Spray-on experiments were performed according to 2³ full factorial design. The effect of binder content, molten binder feed rate, and spray air pressure on granule size and size distribution, granule shape, ?owability and drug release rate was investigated. In the in situ experiments, the influence of binder particle size and binder content was evaluated. Solid-state characterization was performed by means of differential scanning calorimetry, X-ray powder diffraction and Fourier transform infrared spectroscopy.

Results: Size of the granules obtained by spray-on procedure was significantly influenced by binder content and spray air pressure, while the width of particle size distribution was mainly affected by binder feed rate. Spray air pressure showed the most significant influence on granule shape. It was shown that smooth and spherical particles with good flow properties may be obtained by both procedures, spray-on and in situ MG. The results obtained indicated the influence of agglomeration mechanism on granule sphericity, with higher degree of granule sphericity observed when immersion and layering was the dominant mechanism. Paracetamol release from granulates was very rapid, but after compression of the granules into tablets, drug release was considerably slower. Solid-state analysis confirmed that the physical form of the granulate components remained unaffected after the MG process.

Conclusion: The results presented indicate that MG in fluidized bed could be a good alternative to conventional granulation techniques.     

Exploring the Impact of Social Networking on Communication in Organizations

ABSTRACT

Social networking technology has the potential to transform how organizations communicate, cooperate, and connect with key stakeholders. Our research explores how social networking technologies are deployed within organizations and how the use of these technologies is related to effectiveness in organizational communication and promotion. We also identify the facilitating factors and constraints around the use of social networking tools for communication. To examine these questions, we conducted interviews with 131 senior level executives across a broad range of organizations and employed both quantitative and qualitative methods of analysis. The executives were asked to rate numerically and then discuss in narrative form a series of questions about IT strategy and issues affecting social networking in their organization. We find important differences both in the types of tools used as well as how they are used and discuss the implications of our findings for companies seeking to more effectively harness social networking technologies.