Robust estimation of bioaffinity assay fluorescence signals.

In this paper, the challenging problem of robust mean-signal estimation of a single-step microparticle bioaffinity assay is investigated. For this purpose, a density estimation-based robust algorithm (DER) was developed. The DER algorithm was comparatively evaluated with four other parameter estimation methods (mean value, median filtering, least square estimation, Welsch robust m-estimator). Two important questions were raised and investigated: 1) Which of the five methods can robustly estimate the mean bioaffinity signal? and 2) How many microparticles need to be measured in order to obtain an accurate estimate of the mean signal value? To answer the questions, bootstrap and coefficient of variation (CV) analyses were performed. In the CV analysis, the DER algorithm gave the best results: The CV ranged from 0.8% to 4.9% when the number of microparticles used for the mean signal estimation varied from 800 to 30. In the bootstrap analysis of the standard error, the DER algorithm had the smallest variance. As a conclusion, it can be underlined that: 1) of all methods tested, the DER algorithm gave the most consistent and reproducible results according to the bootstrap and CV analysis; 2) using the DER algorithm accurate estimates could be calculated based on 80-100 particles, corresponding to a typical assay measurement time of 1 min; and 3) the investigated bioaffinity signals contained a large number of outliers (observations that severely deviate from the majority of data) and therefore robust techniques were necessary for the mean signal estimation tasks.     

Dependence on the pump frequency of the sensitivity of the rf SQUID

Numerical simulation techniques are used to investigate the frequency dependence of the noise of the hysteretic rf SQUID up to frequencies on the order ofR/L. An exact lower bound for the noise of the instrument is given as a function of the parameters of the SQUID ring, pump frequency, and the temperature. This result is compared with the predictions of a scaling argument and with experiment.     

Heat transfer characteristics of horizontal steam generators under natural circulation conditions

This paper deals with the heat transfer characteristics of horizontal steam generators, particularly under natural circulation (decay heat removal) conditions on the primary side. Special emphasis is on the inherent features of horizontal steam generator behaviour. A mathematical model of the horizontal steam generator primary side is developed and qualitative results are obtained analytically. A computer code, called HSG, is developed to solve the model numerically, and its predictions are compared with experimental data. The code is employed to obtain for VVER 440 steam generators quantitative results concerning the dependence of primary-to-secondary heat transfer efficiency on the primary side flow rate, temperature and secondary level. It turns out that the depletion of the secondary inventory leads to an inherent limitation of the decay energy removal in VVER steam generators. The limitation arises as a consequence of the steam generator tube bundle geometry. As an example, it is shown that the grace period associated with pressurizer safety valve opening during a station black-out is hours instead of the 5–6 hours reported in several earlier studies. (However, the change in core heat-up timing is much less—about 1 h at most.) The heat transfer limitation explains the fact that, in the Greifswald VVER 440 station black-out accident in 1975, the steam generators never boiled dry. In addition, the stability of single-phase natural circulation is discussed and insights on the modelling of horizontal steam generators with general-purpose thermal-hydraulic system codes are also presented.     

The relationship between organizational culture and the deployment of agile methods

Context

Systems development normally takes place in a specific organizational context, including organizational culture. Previous research has identified organizational culture as a factor that potentially affects the deployment systems development methods.

Objective

The purpose is to analyze the relationship between organizational culture and the post-adoption deployment of agile methods.

Method

This study is a theory development exercise. Based on the Competing Values Model of organizational culture, the paper proposes a number of hypotheses about the relationship between organizational culture and the deployment of agile methods.

Results

Inspired by the agile methods thirteen new hypotheses are introduced and discussed. They have interesting implications, when contrasted with ad hoc development and with traditional systems development methods.

Conclusion

Because of the conceptual richness of organizational culture and the ambiguity of the concept of agility the relationship between organizational culture and the deployment of agile systems development forms a rich and interesting research topic. Recognizing that the Competing Values Model represents just one view of organizational culture, the paper introduces a number of alternative conceptions and identifies several interesting paths for future research into the relationship between organizational culture and agile methods deployment.     

Bulk and surface mechanical properties of clay modified HDPE used in liner applications

High‐density polyethylene (HDPE)/clay nanocomposites were prepared by melt blending process. The HDPE was mixed with different organoclays and polyethylene‐grafted‐maleic anhydride was used as a compatibiliser. A masterbatch procedure was used to obtain final organoclays concentrations of 1, 2.5 and 5 wt%. The effects of various types of nanoclays and their concentrations on morphological, thermal and mechanical properties of nanocomposites were investigated. Surface mechanical properties such as instrumented nanohardness, modulus of elasticity and creep were also measured using a nanoindentation technique. Young's, storage and loss moduli, were found to be higher than that of the neat polymer at low loading (2.5 wt%) for clay Cloisite 15A and at higher loading (5 wt%) for clay Nanomer 1.44P. The ultimate strength and the toughness decreased slightly compared to pure HDPE. The differential scanning calorimetry analysis revealed that the peak temperature of the nanocomposites increased with increased clay content while the crystallinity decreased. Also, dynamic mechanical analysis revealed the storage and loss moduli are enhanced by addition of nanoclay. Both mechanical and thermal properties of HDPE/Nanomer 1.44P nanocomposite showed interesting trends. All properties first dropped when 1 wt% of the clay was added. Thereafter, a gradual increase or decrease then followed as the loading of Nanomer was increased. These trends were observed for all mechanical properties. The results obtained from nanoindentation tests for surface mechanical properties also showed similar trend to that of bulk measurements. Based on these measurements a nanoclay additive for a liner grade HDPE was selected. © 2011 Canadian Society for Chemical Engineering     

A dynamic model for plug flow reactor state profiles

A dynamic model for state profiles of a plug flow reactor is developed, including multiple fluid and solid phases. The model is based on conservation of reactor state profile moments along the spatial dimension of the reactor. These moments are transformed analytically into a polynomial approximation at each time step. The method is flexible, and low as well as high order numerical schemes are resulted in by appropriate choice of parameters. A significant advantage of the present method is that boundary conditions of the partial differential equation reactor model are implicitly satisfied via the moment transformation, whereas the polynomial profile in the numerical solution does not have to be forced to satisfy the boundary conditions. The method is tested numerically against analytical solutions in three numerically challenging benchmark cases: prediction of breakthrough curve in packed bed adsorbers; simulation of chromatographic separation; and feeding a step impulse in a plug flow dimerization reactor. It is shown that the high resolution methods result in considerably smaller numerical errors than a simple low-order assumption of piecewise continuous solution.     

Hapticity Vision

The Eyes of the Skin has become an architectural classic. Here, on the publication of a new edition, its author Juhani Pallasmaa reflects on why a sensory understanding of the world has grown in an increasingly digital age. Copyright © 2005 John Wiley & Sons, Ltd.     

Forecasting Ranking in Harness Racing Using Probabilities Induced by Expected Positions

Ranked events are pivotal in many important AI-applications such as Question Answering and recommendations systems. This paper studies ranked events in the setting of harness racing.

For each horse there exists a probability distribution over its possible rankings. In the paper, it is shown that a set of expected positions (and more generally, higher moments) for the horses induces this probability distribution.

The main contribution of the paper is a method, which extracts this induced probability distribution from a set of expected positions. An algorithm is proposed where the extraction of the induced distribution is given by the estimated expectations. MATLAB code is provided for the methodology.

This approach gives freedom to model the horses in many different ways without the restrictions imposed by for instance logistic regression. To illustrate this point, we employ a neural network and ordinary ridge regression.

The method is applied to predicting the distribution of the finishing positions for horses in harness racing. It outperforms both multinomial logistic regression and the market odds.

The ease of use combined with fine results from the suggested approach constitutes a relevant addition to the increasingly important field of ranked events.     

Towards a distinctive body of knowledge for Information Systems experts: coding ISD process knowledge in two IS journals

Abstract.  This paper introduces the idea of coding a practically relevant body of knowledge (BoK) in Information Systems (IS) that could have major benefits for the field. In its main part, the paper focuses on the question if and how an underlying body of action-oriented knowledge for IS experts could be distilled from the IS research literature. For this purpose the paper identifies five knowledge areas as the most important parts for an IS expert's BoK. Two of these are claimed as distinct areas of competence for IS experts: IS application knowledge and IS development (ISD) process knowledge. The paper focuses particularly on ISD process knowledge because it allows the organizing of practically relevant IS knowledge in an action-oriented way. The paper presents some evidence for the claim that a considerable body of practically relevant IS process knowledge might, indeed, exist, but also notes that it is highly dispersed in the IS literature. It then argues that the IS research community should take stock of this knowledge and organize it in an action-oriented way. Based on results from prior work it proposes a four-level hierarchical coding scheme for this purpose. In order to test the idea of coding action-oriented knowledge for IS experts, the paper reports the results of a coded literature analysis of ISD research articles published from 1996 to 2000 in two leading IS journals – Information Systems Journal and MIS Quarterly. The results suggest that ISD approaches form a useful framework for organizing practically relevant IS knowledge.     

Inaccurate prediction of retrieval in a face matrix learning task after right frontal lobe lesions.

This study partly supports the hypothesis that frontal lobe lesions cause impairment of metamemory. Fifty-nine patients with a focal brain lesion and 21 non-brain-damaged patients memorized a 4?×?4 matrix of 16 faces in 6 consecutive trials and predicted the number of locations of faces they would be able to remember before each retrieval. When age-related impairment of learning was adjusted, the patients with right posterior lesions were inferior to the controls and to the patients with right frontal lesions on the total number of correctly placed faces. The patients with right frontal lesions were less accurate than the patients with right posterior lesions or the controls in the prediction of retrieval. The inaccuracy of retrieval prediction in the face test was associated with that in a word-list learning task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)