Social norms in indirect reciprocity with ternary reputations

Indirect reciprocity is a key mechanism that promotes cooperation in social dilemmas by means of reputation. Although it has been a common practice to represent reputations by binary values, either ‘good’ or ‘bad’, such a dichotomy is a crude approximation considering the complexity of reality. In this work, we studied norms with three different reputations, i.e., ‘good’, ‘neutral’, and ‘bad’. Through massive supercomputing for handling more than thirty billion possibilities, we fully identified which norms achieve cooperation and possess evolutionary stability against behavioural mutants. By systematically categorizing all these norms according to their behaviours, we found similarities and dissimilarities to their binary-reputation counterpart, the leading eight. We obtained four rules that should be satisfied by the successful norms, and the behaviour of the leading eight can be understood as a special case of these rules. A couple of norms that show counter-intuitive behaviours are also presented. We believe the findings are also useful for designing successful norms with more general reputation systems.

Numerical Approach on Hybrid PID-AFC Controller using Different Intelligent Tuning Methods to Reduce the Vibration of the Suspended Handle

This paper focusses on the study of vibration attenuations for suspended handle models that are generated from power tools using an intelligent active force control (AFC) tuning strategy. Four types of control schemes are comparatively evaluated in suppressing the vibration of the handle, such as proportional-integral-derivative (PID), PID-AFC-crude approximation (AFCCA), PID-AFC-fuzzy logic (AFCFL) and PID-AFC-iterative learning method (AFCILM) control schemes. In all control schemes, the estimated counter force is generated from the actuating force and appropriate estimated mass M* that has been intelligently tuned to counter the system disturbances. The disturbances are modelled based on the power tools vibration (i.e., internal disturbance) and uncertainties during the operation (i.e., external disturbances). The study shows that the AFCCA scheme demonstrates the best performance when the M(CL) is tuned at 0.04 kg. For the AFCFL control scheme, the best response is obtained for the membership function of trapezoidal shape with M(FL) of 0.0403 kg, while for AFCILM control scheme, the best response is achieved when M(ILM) is tuned to 0.04 kg, with both parameters (A and B) set at 0.6. Overall, PID-AFCCA scheme shows the best performances for all of the case studies, followed by PID-AFCFL and PID-AFCILM. The findings of this study can benefit the power tool manufacturers and provide the basis of effectively intelligent controller design for the power tools application.

Reading against Time

This chapter addresses the concept of “reading against time”: reading that invokes a pressing sense of necessity in order to license a departure from established readerly norms and values. Book 5 of Edmund Spenser's The Faerie Queene has long frustrated those who look to Spenser's poetry for wit, subtlety, and profound spiritual insight, and who expect to work hard and slowly for such rewards. Inspired in part by sympathy for the character of Cymoent, who reminds one that taking one's time with a text is not only a readerly achievement but a readerly luxury, the chapter makes a case for the unpoetic reader, for whom the demands and the insights of the moment supersede the values of patience and diligence on which poetic reading depends. The degree to which such readers have succeeded in extracting value from a part of Spenser's poem that has left more conscientious readers cold suggests that there is something to be said for urgency, haste, brute force, crude approximation, and willful anachronism: for all of the straitening and reductive tendencies of reading in a state of emergency. To put it another way, it is worth considering the etymological link between criticism and crisis.

Numerical Optimization of a Bicylindrical Resonator Impedance: Differences and Common Features Between a Saxophone Resonator and a Bicylindrical Resonator

This paper explores the analogy between a saxophone resonator and a bicylindrical resonator, sometimes called transverse saxophone or cylindrical saxophone. The dimensions of a bicylindrical resonator are optimized numerically to approximate a saxophone impedance. The target is the impedance measured on an usual saxophone. A classical gradient-based non-linear least-square fit function is used. Several cost functions corresponding to distances to the target impedance are assessed, according to their influence on the optimal geometry. Compromises appear between the frequency regions depending on the cost function. It is shown that the chosen cost functions are differentiable and locally convex. The convexity region contains the initial geometrical dimensions obtained by crude approximation of the first resonance frequency of the target. One optimal geometry is submitted to further analysis using descriptors of the impedance. Its deviations from the target saxophone are put into perspective with the discrepancies between the target saxophone and a saxophone from a different manufacture. Descriptors such as harmonicity or impedance peak ratio set the bicylindrical resonator apart from saxophone resonators, despite a good agreement of the resonance frequencies. Therefore, a reed instrument with a bicylindrical resonator could be tuned to produce the same notes as a saxophone, but due to differences in the intrinsic characteristics of the resonator, it should be considered not as a saxophone but as a distinct instrument.

SIMULASI DAN EKSPERIMEN KONTROL AUTOMATIC TURRET GUN

This research presented Active Force Control (AFC) as a control method which is applied to Automatic Turret gun (ATG) in ground combat vehicles This method compares the reference force conducted by actuator with actual force of the mechanical systems that arise due to disturbances. The advantage of AFC method is its ability to handle disturbances effectively without complicated mathematical calculations. The AFC method uses Crude Approximation (CA) in the internal loop controller AFC as inertia matrix estimator as an important part in the control loop. Simulation without load on the azimuth movement shows PID controller produces the best precision with MSE of 0 degrees while RACAFC and RAC method provide MSE 0.267 degrees. In simulation on the elevation movement, the RAC method showed the best results with an estimated MSE of the targets shot of 2.42 degrees, while the PID and RACAFC method are 2.5 and 2.46 degrees. When simulation is conducted with additional load RACAFC method gives the best precision with a MSE of 0.267 and 2:46 degrees, while the PID method was 4.24 and the 10.52 degrees. RAC method produces MSE of 0.7 and 2.87 degrees. With the added load the performance of PID controller decreases. In the experiment on the constructed rig, RAC and RACAFC scheme produce smoother movement trajectory and minimum oscillation compared to the PID controller. In loaded conditions these methods are able to maintain their performance. However, these three methods can still achieve a reference point with or without load in the end of travel time

Effect of Damping and Yielding on the Seismic Response of 3D Steel Buildings with PMRF

The effect of viscous damping and yielding, on the reduction of the seismic responses of steel buildings modeled as three-dimensional (3D) complex multidegree of freedom (MDOF) systems, is studied. The reduction produced by damping may be larger or smaller than that of yielding. This reduction can significantly vary from one structural idealization to another and is smaller for global than for local response parameters, which in turn depends on the particular local response parameter. The uncertainty in the estimation is significantly larger for local response parameter and decreases as damping increases. The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion. It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation. Moreover, the effect of yielding should be explicitly calculated by using complex 3D MDOF models instead of estimating it in terms of equivalent viscous damping. The findings of this paper are for the particular models used in the study. Much more research is needed to reach more general conclusions.

Impact ionization threshold energy of trigonal selenium: An ab initio study

Impact ionization coefficient is a critical parameter that determines the multiplication gain in avalanche photodiodes. The impact ionization coefficient is closely related to the ionization threshold, Eth, which is determined by the band dispersion of the semiconducting material used in detectors. The ionization threshold energy is commonly calculated based on a parabolic band assumption, which provides only a crude approximation. Here we present a first principle study of the ionization threshold energy through an analysis of the electronic structure of trigonal selenium. It is shown that the excess energy of primary charge carriers required to initiate the impact ionization in trigonal selenium can be as low as the band gap, Eg, which is a sharp contrast to the parabolic band approximation that implies Eth = 3/2Eg. Such a low Eth value is a favourable factor for impact ionization.

Large-scale and synoptic meteorology in the south-east Pacific during the observations campaign VOCALS-REx in austral Spring 2008

We present a descriptive overview of the meteorology in the south eastern subtropical Pacific (SEP) during the VOCALS-REx intensive observations campaign which was carried out between October and November 2008. Mainly based on data from operational analyses, forecasts, reanalysis, and satellite observations, we focus on spatio-temporal scales from synoptic to planetary. A climatological context is given within which the specific conditions observed during the campaign are placed, with particular reference to the relationships between the large-scale and the regional circulations. The mean circulations associated with the diurnal breeze systems are also discussed. We then provide a summary of the day-to-day synoptic-scale circulation, air-parcel trajectories, and cloud cover in the SEP during VOCALS-REx. Three meteorologically distinct periods of time are identified and the large-scale causes for their different character are discussed. The first period was characterised by significant variability associated with synoptic-scale systems interesting the SEP; while the two subsequent phases were affected by planetary-scale disturbances with a slower evolution. The changes between initial and later periods can be partly explained from the regular march of the annual cycle, but contributions from subseasonal variability and its teleconnections were important. Across the whole of the two months under consideration we find a significant correlation between the depth of the inversion-capped marine boundary layer (MBL) and the amount of low cloud in the area of study. We discuss this correlation and argue that at least as a crude approximation a typical scaling may be applied relating MBL and cloud properties with the large-scale parameters of SSTs and tropospheric temperatures. These results are consistent with previously found empirical relationships involving lower-tropospheric stability.

A STRUCTURAL RISK-NEUTRAL MODEL OF ELECTRICITY PRICES

The objective of this paper is to present a model for electricity spot prices and the corresponding forward contracts, which relies on the underlying market of fuels, thus avoiding the electricity non-storability restriction. The structural aspect of our model comes from the fact that the electricity spot prices depend on the dynamics of the electricity demand at the maturity T, and on the random available capacity of each production means. Our model explains, in a stylized fact, how the prices of different fuels together with the demand combine to produce electricity prices. This modeling methodology allows one to transfer to electricity prices the risk-neutral probabilities of the market of fuels and under the hypothesis of independence between demand and outages on one hand, and prices of fuels on the other hand, it provides a regression-type relation between electricity forward prices and forward prices of fuels. Moreover, the model produces, by nature, the well-known peaks observed on electricity market data. In our model, spikes occur when the producer has to switch from one technology to the lowest cost available one. Numerical tests performed on a very crude approximation of the French electricity market using only two fuels (gas and oil) provide an illustration of the potential interest of this model.