A frequency-based determination of transient inductance and rotorresistance for field commissioning purposes

The paper presents a deterministic method of estimating the transient inductance and rotor resistance of an induction machine for field commissioning purposes. The parameter values obtained by the method are compared with those for a transient method of commissioning. Skin effects inherent with the transient test are documented. Experimental results for a wide range of machine sizes are included for both methods. The quality of field orientation is established for each method through experimental testing     

Network Communities: Something Old, Something New, Something Borrowed ...

Collaboration has long been of considerable interest to both designers and researchers in the CHI and CSCW communities. This paper contributes to this discussion by proposing the concept of network communities as a new genre of collaboration for this discussion. Network communities are robust and persistent communities based on a sense of locality that spans both the virtual and physical worlds of their users. They are a technosocial construct that requires understanding of both the technology and the sociality embodying them. We consider several familiar systems as well as historical antecedents to describe the affordances these systems offer their community of users. Based on our own experience as designers, users and researchers of a variety of network communities, we extend this initial design space along three dimensions: the boundary negotiations between real and virtual worlds, support for social rhythms and the emergence and development of community. Finally we offer implications for designers, researchers and community members based on our findings.     

Cognitive adaptation theory and breast cancer recurrence: Are there limits?

Relations of the components of cognitive adaptation theory (self-esteem, optimism, control) to quality of life and benefit finding were examined for 70 women (91% Caucasian) diagnosed with Stage I, II, or III breast cancer over 5 years ago. Half of these women experienced a recurrence within the 5 years; the other half remained disease free. Women were matched on age, race, stage of disease, and intervention condition. Baseline perceptions of personal control over illness, but not general self-esteem or optimism, were associated with women's reports of worse physical functioning, worse mental functioning, and less benefit finding 5 years later for recurrent women but not disease-free women. These findings highlight the notion that there may be boundary conditions on the adaptiveness of perceived control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling the electromagnetic response of hearing aids to digitalwireless phones

Interference produced in hearing aids by the pulsed RF signal from digital wireless phones has become an increasingly important issue to wireless phone manufacturers and service providers, hearing aid manufacturers and users, and government regulatory agencies. Development and validation of a comprehensive model of the interaction would greatly benefit the efforts to achieve mutual electromagnetic compatibility (EMC). In order to develop reliable accurate methods to measure hearing aid immunity, an exact mathematical relationship must be demonstrated between the interference generated in hearing aids using a dipole with a standardized test signal [the input referenced interference level (IRIL)] and that produced by actual wireless phones with various signal formats [the overall input referenced interference level (OIRIL)]. A set of theoretical conversion factors has been developed and applied to predict OIRIL interference from the standard IRIL, measured immunity value. A square-law relationship exists within the linear response region of the hearing aid such that each 1 dB increase in RF power (or field strength in decibels V/m) results in a 2 dB sound pressure level (SPL) increase in acoustic power (or sound pressure level). Hence, the IRIL for any given field strength is obtained by doubling (in decibels) the change in field strength and adding the result to the reference IRIL (in decibels SPL). Subtracting 7.60 dB [for time-division multiple access (TDMA)-50 Hz] or 10.68 dB [for TDMA-217 Hz or code-division multiple access (CDMA)] from the IRIL predicts the corresponding OIRIL. The lower and upper limits of the predicted OIRIL are constrained by the measured ambient sound level and the amplifier saturation, respectively. The model predictions are valid when comparable field strength gradients and distributions, separation distances and orientations are maintained between the hearing aid and the RF emitter     

A historical perspective on the “fish tumors or other deformities” beneficial use impairment at Great Lakes Areas of Concern

The Great Lakes Water Quality Agreement defines Areas of Concern as geographic areas that fail to meet the general or specific objectives of the agreement where such failure has caused or is likely to cause impairment of beneficial use of the area's ability to support aquatic life. One of the beneficial use impairments, fish tumors or other deformities, is defined by the International Joint Commission to occur when the incidence rate of fish tumors and other deformities exceeds rates at unimpacted or control sites, or when survey data confirm the presence of neoplastic or preneoplastic liver tumors in bullhead or suckers. Brown bullhead, a benthic species with a limited home range, have frequently been used as indicator species in U.S. Areas of Concern. While there is strong field evidence for an association between PAH exposure and hepatic neoplasia in brown bullhead, laboratory investigations would strengthen the association. There is less evidence linking specific classes of chemicals in the environment to orocutaneous neoplasia in brown bullhead. Studies on orocutaneous neoplasia of brown bullhead should focus on assessing the presence or absence of viruses and on epidermal exposure to specific chemicals and chemical mixtures. Lastly, the effects of covariates such as length, age, and gender on the prevalence of liver and skin neoplasms should be investigated. This paper reviews the state of science on the fish tumors or other deformities beneficial use impairment. Subsequent papers address specific issues related to this impairment and provide recommendations for standardized criteria.     

Convergence of linear interference cancellation multiuser receivers

We consider the convergence in norm of several iterative implementations of linear multiuser receivers, under the assumption of long random spreading sequences. We find that asymptotically, linear parallel interference cancellation diverges for systems loads of greater than about 17%. Using known results from the theory of iterative solutions for linear systems we derive optimal or near-optimal relaxation parameters for parallel (first- and second-order stationary, Chebyshev) and serial cancellation (successive relaxation) methods. An analytic comparison of the asymptotic convergence factor for the various methods is given. Simulations are used to verify results for finite size systems