Evaluation of the Methods for Estimating the Fully Reversed Unnotched Fatigue Limits of Steels

Experimental determination of the fatigue limit is expensive considering the time and effort involved. To overcome this drawback, several empirical relations based on monotonic tensile properties and/or hardness have been developed for estimating the fatigue limit. In this study, ten estimation methods are evaluated and compared using the experimental data of 171 steels from literature. The scatter band criterion, standard deviation criterion, and statistical analysis are all used to evaluate and compare the predictability of the considered empirical relations. It is found that the fatigue limit can be well correlated with the Brinell hardness. In the absence of Brinell hardness, the ultimate tensile strength-based direct estimation method may be an alternative to estimate the fatigue limit of steels. It is not recommended to estimate the fatigue limit by using the indirect method on the basis of Basquin’s fatigue properties estimated by the monotonic tensile properties even though the fatigue limit of steel is often determined by the experimental Basquin’s curve at 106 cycles.

Stability of Measure In High Intellectual Ability: Preliminary Results

Despite there having been improvements in efficiency and ease on test scoring for individuals with high intellectual ability, the stability of these scores is not assured. The main objective of our research is a preliminary detection of variations in test scores from a group of children that were identified as having HIA. This was done by means of a single-time assessment of children currently following an enrichment program. A total of n=26 students participated (19 male and 7 female) in the study. The age range was between 12 and 17 years, being the average age 13.89 years (SD = 1.09 years). Differential Aptitude Test (DAT-5) and Torrance Test of Creative Thinking (TTCT) were used to assess the logical-deductive intellectual skills and creative thinking. The results show that test scores may change in a considerable amount in many supposedly HIA individuals. More than 30% of the variance cannot be attributed to common components in the two measurements points. The scores in creativity were the most fluctuating, something that could be expected of these scales having the lowest reliability indexes. Only eight participants remain steady, according to the one standard deviation criterion, and it is quite notorious that two participants show a decrease in three subscales out of five. On the other hand, two other participants have shown an increase in one subscale as well as a decrease in another. In order to foster HIA individuals and their wellbeing, it is essential to be careful with mistaken diagnoses (false-negatives and false-positives), given the fact that they will lead to developmental consequences.

Distributed Cooperative Spectrum Sensing Algorithm Based on Average Consensus

The existing distributed spectrum sensing algorithms usually assume that the information in interaction channel is totally correct and did not consider noise effect. To solve these problems, a new distributed cooperative spectrum sensing scheme based on average consensus is investigated in this paper. Based on minimum mean square deviation criterion, we design an iterative matrix suitable for consensus algorithm with considering the noise of interaction channel. Simulation results show that the proposed method achieves better detection performance under noise effect of interaction channel and outperforms conventional scheme by 11% at-5dB signal to noise ratio (SNR) and 0.1 false alarm probability.

Robust Optimization of RFID's Investment in Supply Chain with Inaccurate Inventory

Traditional supply chain theory often assumes perfect alignment between system inventory and actual inventory. However, inventory information is usually inaccurate due to many reasons in practice. We hereby describe an expended newsvendor model with inventory inaccuracy who wants to remove this negative effect by investing RFID system. By analyzing the best respond to market factors (commodity availability caused by inventory inaccuracy and tag price of RFID), we generate the optimal order quantity of newsvendor (retailer in this paper) and his minimal regret value. Unlike other paper describing uncertain parameters with probability function, we use only upper limit and lower limits to display demand. We adopt robust deviation criterion to minimize the absolute regret and treat it as the determine principle. Finally, we achieve a result that when commodity availability or tag price meets some specific conditions, investing RFID can be rather profitable.Keywords: inventory inaccuracy, robust optimization, RFID technology

EFFECT OF PULSE NUMBER ON THE PULSE-BASED SYNCHRONIZED-AVERAGING ANALYSIS IN LASER DOPPLER SIGNAL

Pulse parameters calculated from the LDF waveform based on a time-domain synchronized averaging analysis were shown to be able to discriminate the difference in microvascular resistance. However, its applicability may depend on the validation of signal stationarity. In this study, our aim is to investigate the effect of pulse number, which may destroy the signal stationarity, on various pulse LDF parameters. Analysis was performed in data obtained on healthy volunteers. When one pulse parameter is deviated from the standard value for more than 10%, it was regarded as an error; EP (error probability) was then defined as the occurring probability of error. It was revealed in this study that average parameter deviations for FDT and PDT were smaller than 5% for all tested pulse numbers. If we set 10% as the parameter-deviation criterion as well as the acceptable EP range, there should be at least 120 pulses for FDT and PDT, and 210 pulses for FNA and PW. The study presented here has established the criteria for appropriate pulse number to achieve the signal stationarity; we can thus get accurate pulse parameters so that the microcirculatory discriminability of the pulse-based time-averaging analysis on LDF signal can be improved. The proposed quantitative method to verify the validation of signal stationarity when utilizing time-averaging can also be applied to analysis of other bio-signals.