Orientation in buildings: Effects of familiarity, visual access, and orientation aids.

Spatial orientation when walking through a large building complex was investigated with 64 undergraduates. Familiarity with the building was found to facilitate orientation, as revealed by increased accuracy of estimates of targets made by Ss after each tour through the building. Ss who had visited the building frequently before taking part in the experiment improved faster, but their superiority was slight in the final tour. Four tours seemed to be enough to prevent performance impairment after a 1-mo forgetting interval. Reducing visual access to the building by restricting Ss' sight when they walked through it resulted in less improvement. However, this effect was attenuated if before each tour Ss were shown a floor plan displaying the pathways in the building. The method adopted may be useful in field evaluations of building complexes with regard to their ease of orientation and in establishing guidelines for how orientation should be facilitated. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improved algorithm for probe-corrected spherical near-field/far-field transformation

The technique for computation of antenna far fields from spherical near-field measurements has been improved, allowing large antennas to be treated. The efficiency and accuracy is demonstrated for an antenna without rotational symmetry and about 50 wavelengths in diameter.     

New stereology for the recovery of grain-boundary plane distributions in the crystal frame

A new experimental method is given for recovering the probability-distribution function S _v ( |Δg). The function S _v ( |Δg) is the grain-boundary area per unit volume as a function of grain-boundary plane orientation ( ), given a lattice misorientation (Δg) between the adjoining grains. The grain-boundary normal ( ) is expressed in the crystal frame in which the misorientation Δg originates. The proposed method recovers the three-dimensional S _v ( |Δg) function using data taken from two-dimensional section planes. The method requires the measurement of many grain-boundary trace (in-plane) angles and lengths associated with grain boundaries of lattice misorientation. All such boundary traces may be observed from a single section plane if the crystallographic texture is sufficiently random. In heavily textured microstructures, the method requires the researcher to observe traces from multiple oblique section planes cut through the material. A method of quantitatively estimating whether the texture is sufficiently random is given. Simulations on both textured and nontextured microstructures demonstrate the validity of the method. Experimentally, the new method is used to analyze boundaries of misorientation (Σ3) observed in 304 stainless steel. Calculated grain-boundary plane-probability functions are shown to be consistent with what is already known. This article is based on a presentation made at the symposium “Characterization and Representation of Material Microstructures in 3-D” held October 8–10, 2002, in Columbus, OH, under the auspices of ASM International’s Phase Transformations committee.     

Screening for diabetic retinopathy using computer based image analysis and statistical classification

Diabetic retinopathy is one of the most common causes of blindness in Europe. However, efficient therapies do exist. An accurate and early diagnosis and correct application of treatment can prevent blindness in more than 50% of all cases. Digital imaging is becoming available as a means of screening for diabetic retinopathy. As well as providing a high quality permanent record of the retinal appearance, which can be used for monitoring of progression or response to treatment, and which can be reviewed by an ophthalmologist, digital images have the potential to be processed by automatic analysis systems. We have described the preliminary development of a tool to provide automatic analysis of digital images taken as part of routine monitoring of diabetic retinopathy in our clinic. Various statistical classifiers, a Bayesian, a Mahalanobis, and a KNN classifier were tested. The system was tested on 134 retinal images. The Mahalanobis classifier had the best results: microaneurysms, haemorrhages, exudates, and cotton wool spots were detected with a sensitivity of 69, 83, 99, and 80%, respectively.     

The generalized fixed-charge network design problem

In this paper we present the generalized fixed-charge network design (GFCND) problem. The GFCND problem is an instance of the so-called generalized network design problems. In such problems, clusters instead of nodes have to be interconnected by a network. The network interconnecting the clusters is a fixed-charge network, and thus the GFCND problem generalizes the fixed-charge network design problem. The GFCND problem is related to the more general problem of designing hierarchical telecommunication networks.     

The evolving profession of psychology: Comment on Lowe Hays-Thomas's (2000) "The silent conversation."

[Correction Notice: An erratum for this article was reported in Vol 31(4) of Professional Psychology: Research and Practice (see record 2007-17397-001). On page 346 in the author note, Louisiana Southern University was given as the university where Tommy T. Stigall received his PhD. The correct university is Louisiana State University.] The authors comment on R. Lowe Hays-Thomas (2000; see record 2000-03894-016). The article begins with a few comments about the master's-degree issue and then examines the evolution of professional psychology in relationship to the master's issue over the past 50 years and into the future. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Current status of CMOS low voltage and low power wireless IC designs

This paper surveys recent research on CMOS low voltage and low power IC designs for wireless applications. Advancements and challenges in using nanometer IC processes are addressed, and the impacts of device scaling on wireless systems are discussed. Recent advances in device technologies and system architectures are presented. State-of-the-art low power wireless systems, both from academia and from industry, are summarized. Circuit design techniques and challenges for low voltage and low power applications are discussed, along with RF performance and power trade-offs. Examples of common RF building blocks, e.g. LNA's and VCO's, designed for sub-1V power supplies are presented.     

Analysis of Circularly Polarized Hemispheroidal Dielectric Resonator Antenna Phased Arrays Using the Method of Auxiliary Sources

The method of auxiliary sources is employed to model and analyze probe-fed hemispheroidal dielectric resonator antennas and arrays. Circularly polarized antenna elements of different designs are analyzed, and impedance bandwidths of up to 14.7% are achieved. Selected element designs are subsequently employed in a seven-element phased array. The array performance is analyzed with respect to scan loss and main beam directivity as a function of scan angle and frequency, and the influence of element separation is investigated.     

Construction Delays in Hong Kong Civil Engineering Projects

Construction delays are common in civil engineering projects in Hong Kong, inevitably resulting in contractual claims and increased project cost. This study was aimed, first, at gathering the perceptions of civil construction practitioners on how significant are the causes of delay; and, second, investigating whether the suggestions as stated in the report of the Construction Industry Review Committee (the Committee comprises members with good standing and knowledge in the construction and related fields as well as those from other professions who are responsible for examining the current state of the construction industry in terms of its output quantity, the quality of work, its environmental friendliness, site safety, its workforce and the system of supervision) are applicable to and effective at mitigating the corresponding delays with reference to a ranking order established using the mean score method. The extent of the differences in perception among the different respondent groups on these two issues was also examined using the rank agreement factor (RAF), percentage agreement (PA), and percentage disagreement (PD). The differences in the perceptions of the respondents on the significance of delays and the actual causes of delays for the six projects studied were also examined. The results of the study showed that the respondents tended to admit their own faults as shown in the top ten significant causes of delay. A strong consensus was found between the client and consultant groups on the significance of the various causes of delay (PA = 74%) and the effectiveness of mitigation measures (PA = 67%) compared with the other pairs of groups. The consultant and contractor groups held extremely different perceptions regarding the significance of various delay causes (RAF = 4.9 and PD = 32%) and the effectiveness of corresponding mitigation measures (RAF = 6.2 and PD = 47%). It is believed that the findings can provide much more insight for the construction practitioners as well as the researchers and thus help to improve the productivity and overall performance of civil construction projects in Hong Kong.