Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads

The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed

Synthesis, Spectral and Dyeing Performance Studies of 4-(2-Aminmo-5-nitro-phenylazo)-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one Complexes with Some Metal Ions

The ligand 4-(2-aminmo-5-nitro-phenylazo)-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one derived from 4-aminoantipyrine and 4-nitroaniline was synthesized. The synthesized ligand was characterized by 1HNMR, FT-IR, UV-Vis spectra and (C.H.N) analysis. Complexes of (YIII and LaIII ) with the ligand were prepared in aqueous ethanol with a 1:2 M:L ratio and at optimum pH. The prepared complexes were characterized by using flame atomic absorption, FT-IR, UV-Vis spectra,(C.H.N) analysis and conductivity measurement. The stoichiometry of complexes was studied by the mole ratio and job methods. A concentration range (1×10-4 - 3×10-4 M) obeyed Beer's law, the complex solutions show high values of molar absorption. On the basis of physicochemical data octahedral geometries were attributed for the complexes. All prepared compounds exhibited good antibacterial activity, the ligand and their complexes were application to cotton fabric and study of the detergent fastnes

A simplified analytical approach for optimal planning of distributed generation in electrical distribution networks

DG-integrated distribution system planning is an imperative issue since the installing of distributed generations (DGs) has many effects on the network operation characteristics, which might cause significant impacts on the system performance. One of the most important characteristics that mostly varies because of the installation of DG units is the power losses. The parameters affecting the value of the power losses are number, location, capacity, and power factor of the DG units. In this paper, a new analytical approach is proposed for optimally installing DGs to minimize power loss in distribution networks. Different parameters of DG are considered and evaluated in order to achieve a high loss reduction in the electrical distribution networks. The algorithm of the proposed approach has been implemented using MATLAB software and has been tested and investigated on 12-bus, 33-bus, and 69-bus IEEE distribution test systems. The results show that the proposed approach can provide an accurate solution via simple algorithm without using exhaustive process of power flow computations

Self-Repairing Disk Arrays

As the prices of magnetic storage continue to decrease, the cost of replacing failed disks becomes increasingly dominated by the cost of the service call itself. We propose to eliminate these calls by building disk arrays that contain enough spare disks to operate without any human intervention during their whole lifetime. To evaluate the feasibility of this approach, we have simulated the behavior of two-dimensional disk arrays with n parity disks and n(n-1)/2 data disks under realistic failure and repair assumptions. Our conclusion is that having n(n+1)/2 spare disks is more than enough to achieve a 99.999 percent probability of not losing data over four years. We observe that the same objectives cannot be reached with RAID level 6 organizations and would require RAID stripes that could tolerate triple disk failures.Comment: Part of ADAPT Workshop proceedings, 2015 (arXiv:1412.2347

Optimization in Knowledge-Intensive Crowdsourcing

We present SmartCrowd, a framework for optimizing collaborative knowledge-intensive crowdsourcing. SmartCrowd distinguishes itself by accounting for human factors in the process of assigning tasks to workers. Human factors designate workers' expertise in different skills, their expected minimum wage, and their availability. In SmartCrowd, we formulate task assignment as an optimization problem, and rely on pre-indexing workers and maintaining the indexes adaptively, in such a way that the task assignment process gets optimized both qualitatively, and computation time-wise. We present rigorous theoretical analyses of the optimization problem and propose optimal and approximation algorithms. We finally perform extensive performance and quality experiments using real and synthetic data to demonstrate that adaptive indexing in SmartCrowd is necessary to achieve efficient high quality task assignment.Comment: 12 page

Signal words and signal icons in application control and information technology exception messages - Hazard matching and habituation effects: Working paper series--06-05

People often encounter warnings in various life situations. These warnings typically include a variety and combination of signal phrases (e.g., "Deadly") and signal icons (e.g., a skull and cross-bones). Users of information technology (IT) frequently encounter such signal words and icons in "exception messages" that appear on computer screens when the user performs an incorrect action or if a condition could arise that may result in a negative occurrence. For example, in the context of accounting application controls which deal with exposures within specific computer application programs. This paper reports the results of two experiments. The first examines the "arousal strength" associated with various signal words and signal icons that are commonly used in IT exception messages. An elicitation exercise was completed by 316 participants, in which each participant viewed exception messages containing combinations of signal words and signal icons and provided their perception as to the severity of a computer problem communicated by the exception message. The results can be used to achieve "hazard matching," whereby the severity of hazard that is implied by the signal word and icon within the exception message can be matched to the level of the potential hazard faced by the user. The second experiment investigated the factor of habituation and if the negative results of habituation can be overcome through the design of exception messages. A strong habituation effect was found to exist and the effect was also found to be mitigated by altering the signal word and icon combination of an exception message

The Interacting Branching Process as a Simple Model of Innovation

We describe innovation in terms of a generalized branching process. Each new invention pairs with any existing one to produce a number of offspring, which is Poisson distributed with mean p. Existing inventions die with probability p/\tau at each generation. In contrast to mean field results, no phase transition occurs; the chance for survival is finite for all p > 0. For \tau = \infty, surviving processes exhibit a bottleneck before exploding super-exponentially - a growth consistent with a law of accelerating returns. This behavior persists for finite \tau. We analyze, in detail, the asymptotic behavior as p \to 0.Comment: 4 pages, 4 figure

Detection of Sex-Related Differential Item Functioning in Raven’s Standard Progressive Matrices Test Using the Mantel-Haenszel Method

This study aimed to determine the presence of sex-related differential item functioning (DIF) in Raven’s Standard Progressive Matrices (SPM) Test. The research design was a comparative study, where boys formed the focal group and girls formed the reference group. The software used was SPSS-v26, and binary data of focal and reference groups were analyzed using jMetrik software to detect DIF according to the Mantel-Haenszel method. A total of 1032 students (49.6% boys and 50.4% girls), 570 from intermediate school and 462 from secondary school, were selected from 24 schools using a stratified random-sampling procedure. The statistical analyses showed that the Raven’s Standard Progressive Matrices (SPM) Test was one-dimensional. The results showed that, of five moderate DIF items, four items favored the focal group (boys), and one item favored the reference group (girls). The results also showed two large DIF items; the direction of the one item favored the reference group (girls), and the direction of the second item favor the focal group (boys). The findings showed that there were several unbiased items, but some were clearly biased against female performance. According to these findings, we recommend reanalyzing the data using methods depending on the item response theory, such as the logistic regression, simultaneous item bias test (SIB) or IRT-likelihood ratio (IRT-LR) methods to confirm the results seen here. Keywords: Differential Item Functioning (DIF), Bias Item, Reference Group, Focal Group DOI: 10.7176/JEP/11-29-10 Publication date:October 31st 202