Bandwidth optimization of optical data links by use of error-control codes

A design approach to optimizing the bandwidth of optical data links while simultaneously decreasing the bit-error rate is proposed. Mathematical analysis indicates that bandwidth gains by factors of 10-60 with power gains of as much as 8.9 dB are possible. To achieve these performance levels requires several innovations. First, conventional forward error-correcting codes cannot be used because of their excessive hardware cost. A reasonably powerful multidimensional parity-based error-control code is proposed and analyzed. These codes offer excellent error detection and moderate error-correction capabilities. Most importantly, they can operate at the fast clock rates that are required. Second, a hybrid automatic-repeat-request protocol is exploited to correct complex error patterns. In thermal-noise-limited systems this unique combination allows the optical clock rate to be increased significantly, thereby resulting in large bandwidth increases. The proposed design approach can be used in optical data links in which propagation delays are moderate and is applicable to fibers that exploit wavelength-division multiplexing or time-division multiplexing, one-dimensional parallel-fiber ribbons, and two-dimensional optical data links that use free space or guided waves. Several design examples are illustrated.     

Field-programmable smart-pixel arrays: design, VLSI implementation, and applications

A smart-pixel array is a two-dimensional array of optoelectronic devices that combine optical inputs and outputs with electronic processing circuitry. A field-programmable smart-pixel array (FP-SPA) is a smart-pixel array capable of having its electronic functionality dynamically programmed in the field. Such devices could be used in a diverse range of applications, including optical switching, optical digital signal processing, and optical image processing. We describe the design, VLSI implementation, and applications of a first-generation FP-SPA implemented with the 0.8-microm complementary metal-oxide semiconductor-self-electro-optic effect device technology made available through the Lucent Technologies-Advanced Research Projects Agency Cooperative (Lucent/ARPA/COOP) program. We report spice simulations and experimental results of two sample applications: In the first application, we configure this FP-SPA as an array of free-space optical binary switches that can be used in optical multistage networks. In the second, we configure the device as an optoelectronic transceiver for a dynamically reconfigurable free-space intelligent optical backplane called the hyperplane. We also describe the testing setup and the electrical and the optical tests that demonstrate the correct functionality of the fabricated device. Such devices have the potential to reduce significantly the need for custom design and fabrication of application-specific optoelectronic devices in the same manner that field-programmable gate arrays have largely eliminated the need for custom design and fabrication of application-specific gate arrays, except in the most demanding applications.     

Lymph node metastasis in breast cancer: common prognostic markers lack predictive value

Isoflavones are present in soybeans and its products in concentrations up to 300 mg/100 g, have estrogenic and antiestrogenic properties, and may be protective against hormone-related cancers. The purpose of this cross-sectional study was to investigate the association between urinary isoflavone excretion and self-reported soy intake. A total of 102 women of Caucasian, Native Hawaiian, Chinese, Japanese, and Filipino ancestry completed a dietary questionnaire for soy products consumed during the last year and during the 24-h period before urine collection. Overnight urine samples were analyzed for coumestrol and the soy isoflavones genistein, daidzein, and glycitein and their main human metabolites by reverse-phase high-pressure liquid chromatography. Soy protein and isoflavone intake (predominantly from tofu) were estimated using published nutritional databases. Wilcoxon's rank-sum test scores and Spearman rank correlation coefficients were computed. Japanese women excreted more daidzein, genistein, and glycitein than did Caucasian women, whereas Caucasian women excreted slightly more coumestrol. Soy intake differed significantly among ethnic groups. Dietary soy protein and isoflavone intakes during the previous 24 h were positively related to urinary isoflavone excretion [rs = 0.61 (P < 0.0001) and 0.62 (P < 0.0001), respectively]. Urinary excretion of isoflavones was also related to annual dietary soy protein and isoflavone intake [rs = 0.32 (P < 0.0012) and 0.31 (P < 0.0016), respectively]. The strong correlation between urinary isoflavone excretion and self-reported soy intake validates the dietary history questionnaire that is now used in a study exploring dietary risk factors for breast cancer.     

On reliability of a certain elementary safety system

The paper deals with the determination of reliability of an elementary safety system which consists of two identical elements used simultaneously (hot reserve) whereas for correct system operation is enough when one out of it is good. The operation time is so short that is assumed it is of zero length. Knowing the reliability of element, reliability of system is found.     

Children's use of the common ground in interpreting ambiguous referential utterances.

Common ground is contextual information shared by a listener and speaker that enables the listener to convert an ambiguous utterance to an informative communication. Four experiments examined young children's understanding of the common ground in interpreting ambiguous referential utterances. Kindergarten and 2nd-grade children and college students were read short vignettes containing statement, joint activity, status common ground, and an ambiguous or informative utterance about a display of 4–6 object drawings. The subjects were asked (a) whether the listener knew which object to pick (Experiment 1), (b) to pick an object themselves or choose "none" (Experiment 2), (c) the source of the listener's knowledge in the context or utterance (Experiment 3), and (d) whether a designated object was the "right one," the one the speaker "meant," or the one the speaker "could have meant" (Experiment 4). Even the kindergarten children used statement information effectively in interpreting ambiguous utterances, and all groups had difficulty using status information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fostering scholarly productivity through academic and internship research training environments.

How can training programs foster counseling and clinical psychologists' scholarly productivity? This study examined the impact of academic and internship research training environments (RTEs) on the scholarly activity of 223 early career professionals. Results supported the construct validity of the Internship Research Training Environment scale through cross-validation and confirmatory factor analysis. Findings revealed differences in perceptions of the internship RTE and scholarly productivity as a function of academic training philosophy and internship training philosophy. Finally, results suggested that academic and internship RTEs could influence research interest and scholarly productivity indirectly by enhancing research self-efficacy and research outcome expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ultrasonic inspection of austenitic steel joints by coupled‐head scanning

This work covers short-circuit metal transfer in the MIG/MAG process, where the current is the direct regulation variable, in contrast with the conventional mode in which the direct regulation variable is the voltage. It sets out the general theory for this technique and describes a new system, not yet commercially offered, developed by LABSOLDA at UFSC. The control bases of the process are described, presenting oscillograph results and performance results in relation to root passes and production of splatter. In addition, some results from an existing commercial system are set out with the aim of making direct comparisons between the control strategies and the implications for the largest dependent factors, such as drop diameters, average current, arc efficiency and arc power. Questions are posed such as the criteria for monitoring the variables and the calculations for arc power, which are as important for these new technologies as they are in the case of conventional systems.     

Functional Warsaw: A challenge from the past

This article describes the planning concept known as ‘Functional Warsaw’ (Warszawa Funkejonalna) prepared in 1934 by the architects and urban planners Jan Chmielewski and Szymon Syrkus. This planning exercise can be considered both as a most spectacular example of progressive trends in Polish urban planning thought in the inter‐war period, and as an attempt to respond to the challenge created by the widely known ‘Charter of Athens’ regarding the postulates of the functional urban region.

The article is divided into four sections. The first considers the national background in which circumstances conducive to development of urban thought in Poland created favourable conditions for the relatively early practice of regional planning. The next section deals with the international context, the influence of the foreign avant garde movement as represented in CIAM (the International Congresses of Modern Architecture). In the third section, the authors’ model of the functional urbanized region is described; some critical comments are offered. In the last section the impact of Functional Warsaw is considered against the development of spatial planning not only of Warsaw but of the country as well.