An Efficient Multibody Dynamics Model for Internal Combustion Engine Systems

The equations of motion for the major components in an internalcombustion engine are developed herein using a recursive formulation.These components include the (rigid) engine block, pistons, connectingrods, (flexible) crankshaft, balance shafts, main bearings, and enginemounts. Relative coordinates are employed that automatically satisfy allconstraints and therefore lead to the minimum set of ordinarydifferential equations of motion. The derivation of the equations ofmotion is automated through the use of computer algebra as the precursorto automatically generating the computational (C or Fortran) subroutinesfor numerical integration. The entire automated procedure forms thebasis for an engine modeling template that may be used to supportthe up-front design of engines for noise and vibration targets.This procedure is demonstrated on an example engine under free(idealized) and firing conditions and the predicted engine responses arecompared with results from an ADAMS model. Results obtained by usingdifferent bearing models, including linear, nonlinear, and hydrodynamicbearing models, are discussed in detail.     

Unscented Kalman filter based nonlinear model predictive control of a LDPE autoclave reactor

This paper presents a multivariable nonlinear model predictive control (NMPC) scheme for the regulation of a low-density polyethylene (LDPE) autoclave reactor. A detailed mechanistic process model developed previously was used to describe the dynamics of the LDPE reactor and the properties of the polymer product. Closed-loop simulations are used to demonstrate the disturbance rejection and tracking performance of the NMPC algorithm for control of reactor temperature and weight-averaged molecular weight (WAMW). In addition, the effect of parametric uncertainty in the kinetic rate constants of the LDPE reactor model on closed-loop performance is discussed. The unscented Kalman filtering (UKF) algorithm is employed to estimate plant states and disturbances. All control simulations were performed under conditions of noisy process measurements and structural plant–model mismatch. Where appropriate, the performance of the NMPC algorithm is contrasted with that of linear model predictive control (LMPC). It is shown that for this application the closed-loop performance of the UKF based NMPC scheme is very good and is superior to that of the linear predictive controller.     

Market power and the deregulation of special access service by the Federal Communications Commission

In 1999, the Federal Communications Commission adopted an order granting complete deregulation of the rates for special access service for specific metropolitan statistical areas based on an objective showing that there was potential competition in that market. This was done in an environment where the local exchange carriers (LECs) subject to price caps were earning a rate of return in excess of 22% with the rate of return on an upward trend. By 2002, the average rate of return across all price cap LECs topped 35%. The questions investigated in this article are whether the price cap LECs have market power in supplying special access service and whether they have taken advantage of this. The data clearly show that this is the case. Given the prevailing situation, there is a clear need to revisit the pricing flexibility order. First, the product market for special access service needs to be more carefully examined and, second, the metrics used to define the potential for competition need to be revamped.     

AmbiKraf

This paper presents, AmbiKraf, a non-emissive fabric display that subtly animates patterns on common fabrics. We use thermochromic inks and peltier semiconductor elements to achieve this technology. With this technology we have produced numerous prototypes from animated wall paintings to pixilated fabric displays. The ability of this technology to subtly and ubiquitously change the color of the fabric itself has made us able to merge different fields and technologies with AmbiKraf. In addition, with an animated room divider screen, Ambikraf merged its technology with Japanese Byobu art to tighten the gap between traditional arts and contemporary technologies. Through this AmbiKraf Byobu art installation and other installations, we discuss the impact of this technology as a ubiquitous fabric display. With focus to improvements of some limitations of the existing system, we present our future vision that enables us to merge this technology into more applications fields thus making this technology a platform for ubiquitous interactions on our daily peripherals.     

Gender Differences in Mouse and Cursor Movements

Computer cursor and mouse activities such as moving, pointing, selecting, and dragging are essential parts of everyday interactions. Yet it is unknown how men and women differ in the way they move computer cursors. This study examines gender differences in movements of computer cursors. In one experiment, the authors measured trajectories of computer cursors every 20 ms in a simple choice-reaching task and tested the extent to which movement features related to controlling and targeting diverge between male and female participants. Results showed significant gender differences in cursor motions. Female participants deviated from the straight path toward the target location to a larger degree than did male participants, and female participants showed more backward motions (deviating backward from the target location) than did male participants. Implications for sources of these gender differences, user interface and input device design, and musculoskeletal disorders in women are also discussed.     

Towards adaptive learning with improved convergence of deep belief networks on graphics processing units

In this paper we focus on two complementary approaches to significantly decrease pre-training time of a deep belief network (DBN). First, we propose an adaptive step size technique to enhance the convergence of the contrastive divergence (CD) algorithm, thereby reducing the number of epochs to train the restricted Boltzmann machine (RBM) that supports the DBN infrastructure. Second, we present a highly scalable graphics processing unit (GPU) parallel implementation of the CD-k algorithm, which boosts notably the training speed. Additionally, extensive experiments are conducted on the MNIST and the HHreco databases. The results suggest that the maximum useful depth of a DBN is related to the number and quality of the training samples. Moreover, it was found that the lower-level layer plays a fundamental role for building successful DBN models. Furthermore, the results contradict the pre-conceived idea that all the layers should be pre-trained. Finally, it is shown that by incorporating multiple back-propagation (MBP) layers, the DBNs generalization capability is remarkably improved.     

Vocal learning in the grey parrot (Psittacus erithacus): Effects of species identity and number of trainers.

Grey parrots (Psittacus erithacus) learn referential English labels when they view and interact with 2 humans who model vocal labeling and who demonstrate referentiality and functionality of a label (I. M. Pepperberg, 1990a). To test if both trainers are necessary, the authors contrasted 2-trainer modeling with training by 1 human who presented targeted labels to a bird in concert with appropriate items, who asked questions, and who would reward attempts at the label with the item. The bird was also tutored by either 1 or 2 interactive humans in conjunction with a conspecific who already used referential labels. Referential labels were learned from multiple live tutors but not a single trainer. Presence of a conspecific enhanced learning compared with single-trainer sessions but did not affect acquisition in 2-human sessions. Specific aspects of paired tutoring seem critical for acquiring referential vocal labels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The demand for energy for irrigation in the USA

There seems to be some question concerning the relationship between irrigation and the price of energy. Did changes in the price of energy actually impact irrigation in the USA? Additionally, the substitution between alternative types of energy seems to be a possibility for irrigation. Whether in fact it occurred is another matter. In this study, an appropriate model is developed and estimated to address the issues. The specific energy types considered include motor gasoline, diesel fuel, liquefied petroleum gas, natural gas and electrical energy. The results for 1978 and for 1980 clearly indicate that energy use for irrigation is responsive to the price of energy. Additionally, some substitution between energy types took place during this period. Finally, when the question of the stability of the demand for the various energy types is addressed, the suggestion is that the demand for the energy types considered was stable for the 1978 and 1980 periods.     

A model for the creep of concrete

Porosity and density changes were measured for a series of mortar specimens and a series of cement paste specimens subjected to various compressive stress histories during desorption and sorption cycles.

It was found that hydration is inhibited by compressive stress. Under normal basic and drying creep, the effect of compressive stress is to reduce the porosity and increass the interlayer volume with a corresponding increase in the weight of water retained in the interlayer spaces. For specimens completely dried under load the interlayer volume decreases with load. A model for the creep of concrete is advanced in which, under sustained stress, interlayer volume increases as a result of physical distortion of the solid sheets of cement hydrate.