Individual Units (individual + unit)

Distribution by Scientific Domains


Selected Abstracts


Threshold optimization for weighted voting classifiers

NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 4 2003
G. Levitin
Abstract Weighted voting classifiers considered in this paper consist of N units each providing individual classification decisions. The entire system output is based on tallying the weighted votes for each decision and choosing the one which has total support weight exceeding a certain threshold. Each individual unit may abstain from voting. The entire system may also abstain from voting if no decision support weight exceeds the threshold. Existing methods of evaluating the reliability of weighted voting systems can be applied to limited special cases of these systems and impose some restrictions on their parameters. In this paper a universal generating function method is suggested which allows the reliability of weighted voting classifiers to be exactly evaluated without imposing constraints on unit weights. Based on this method, the classifier reliability is determined as a function of a threshold factor, and a procedure is suggested for finding the threshold which minimizes the cost of damage caused by classifier failures (misclassification and abstention may have different price.) Dynamic and static threshold voting rules are considered and compared. A method of analyzing the influence of units' availability on the entire classifier reliability is suggested, and illustrative examples are presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 322,344, 2003. [source]


Pesticide residues in food,acute dietary exposure,

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2004
Denis Hamilton
Abstract Consumer risk assessment is a crucial step in the regulatory approval of pesticide use on food crops. Recently, an additional hurdle has been added to the formal consumer risk assessment process with the introduction of short-term intake or exposure assessment and a comparable short-term toxicity reference, the acute reference dose. Exposure to residues during one meal or over one day is important for short-term or acute intake. Exposure in the short term can be substantially higher than average because the consumption of a food on a single occasion can be very large compared with typical long-term or mean consumption and the food may have a much larger residue than average. Furthermore, the residue level in a single unit of a fruit or vegetable may be higher by a factor (defined as the variability factor, which we have shown to be typically ×3 for the 97.5th percentile unit) than the average residue in the lot. Available marketplace data and supervised residue trial data are examined in an investigation of the variability of residues in units of fruit and vegetables. A method is described for estimating the 97.5th percentile value from sets of unit residue data. Variability appears to be generally independent of the pesticide, the crop, crop unit size and the residue level. The deposition of pesticide on the individual unit during application is probably the most significant factor. The diets used in the calculations ideally come from individual and household surveys with enough consumers of each specific food to determine large portion sizes. The diets should distinguish the different forms of a food consumed, eg canned, frozen or fresh, because the residue levels associated with the different forms may be quite different. Dietary intakes may be calculated by a deterministic method or a probabilistic method. In the deterministic method the intake is estimated with the assumptions of large portion consumption of a ,high residue' food (high residue in the sense that the pesticide was used at the highest recommended label rate, the crop was harvested at the smallest interval after treatment and the residue in the edible portion was the highest found in any of the supervised trials in line with these use conditions). The deterministic calculation also includes a variability factor for those foods consumed as units (eg apples, carrots) to allow for the elevated residue in some single units which may not be seen in composited samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. Additional information such as percentage commodity treated and combination of residues from multiple commodities may be incorporated into probabilistic calculations. The IUPAC Advisory Committee on Crop Protection Chemistry has made 11 recommendations relating to acute dietary exposure. Copyright © 2004 Society of Chemical Industry [source]


THE PRICE OF METAPHOR

HISTORY AND THEORY, Issue 1 2005
JOSEPH FRACCHIA
ABSTRACT In his critical response to our skeptical inquiry, "Does Culture Evolve?" (History and Theory, Theme Issue 38 [December 1999], 52,78), W. G. Runciman affirms that "Culture Does Evolve." However, we find nothing in his essay that convinces us to alter our initial position. And we must confess that in composing an answer to Runciman, our first temptation was simply to urge those interested to read our original article,both as a basis for evaluating Runciman's attempted refutation of it and as a framework for reading this essay, which addresses in greater detail issues we have already raised. Runciman views the "selectionist paradigm" as a "scientific""puzzle-solving device" now validated by an "expanding literature" that has successfully modeled social and cultural change as "evolutionary." All paradigms, however, including scientific ones, give rise to self-validating "normal science." The real issue, accordingly, is not whether explanations can be successfully manufactured on the basis of paradigmatic assumptions, but whether the paradigmatic assumptions are appropriate to the object of analysis. The selectionist paradigm requires the reduction of society and culture to inheritance systems that consist of randomly varying, individual units, some of which are selected, and some not; and with society and culture thus reduced to inheritance systems, history can be reduced to "evolution." But these reductions, which are required by the selectionist paradigm, exclude much that is essential to a satisfactory historical explanation,particularly the systemic properties of society and culture and the combination of systemic logic and contingency. Now as before, therefore, we conclude that while historical phenomena can always be modeled selectionistically, selectionist explanations do no work, nor do they contribute anything new except a misleading vocabulary that anesthetizes history. [source]


Questioning the impact of the ,graduatization' of the managerial labour force upon the management of human resources in the Scottish hotel industry

INTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 4 2000
Arthur Ingram
Abstract This paper outlines the findings of a questionnaire survey returned by 125 Scottish hotels from a sample of 500 small and middle-sized enterprises. We asked questions on the level of impact that hospitality graduates have had upon human resource management practices within individual units. The research reports that, although the cumulative graduatization of the managerial workforce appears to be under way, the main route to a permanent management post still remains one of practical work experience, rather than the attainment of a hospitality-related degree. Although manpower planning is widely used by line managers for managing the conditions of local/external labour markets and operatives' jobs, there is less evidence of a systematic approach to the management of graduate careers/skills or of the management of internal job structures and labour market processes in order to improve the quality of customer service. Our work suggests a need for smaller hotels to strike a fresh balance between traditional operationally driven approaches to people management and strategic human resource management frameworks. [source]


International field test results of the Observable Indicators of Nursing Home Care Quality instrument

INTERNATIONAL NURSING REVIEW, Issue 4 2002
FAAN , M. Rantz RN
Abstract Researchers at the University of Missouri-Columbia developed the Observable Indicators of Nursing Home Care Quality instrument to measure the dimensions of nursing home care quality during a brief on-site visit to a nursing home. The instrument has been translated for use in Iceland and used in Canada. Results of the validity and reliability studies using the instrument in 12 nursing homes in Reykjavik, in a large Veterans Home in Ontario with 14 units tested separately, and in 20 nursing homes in Missouri, are promising. High-content validity was observed in all countries, together with excellent inter-rater reliability and coefficient alpha. Test,retest reliabilities in Iceland and Missouri were good. Results of the international field test of the Observable Indicators of Nursing Home Care Quality instrument points to the usefulness of such an instrument in measuring nursing home care quality following a quick on-site observation in a nursing facility. The instrument should be used as a facility-wide assessment of quality, rather than for individual units within a facility. We strongly recommend its use by practising nurses in nursing homes to assess quality of care and guide efforts to improve care. We recommend its use by researchers and consumers and further testing of the use of the instrument with regulators. [source]


The impact of cross-sectional data aggregation on the measurement of vertical price transmission: An experiment with German food prices

AGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 4 2006
Stephan von Cramon-Taubadel
The impact of cross-sectional aggregation over individual retail stores on the estimation and testing of vertical price transmission between the wholesale and retail levels is investigated using a unique data set of individual retail prices in Germany. Systematic differences between the results of estimations using aggregated data on the one hand, and disaggregated data on the other, are discussed theoretically and confirmed empirically. The results suggest that estimation with aggregated data can generate misleading conclusions about price transmission behavior at the level of the individual units (i.e., retail stores) that underlie these aggregates. [JEL classifications: C22, L11, D40] © 2006 Wiley Periodicals, Inc. Agribusiness 22: 505,522, 2006. [source]


Fault-tolerant control of process systems using communication networks

AICHE JOURNAL, Issue 6 2005
Nael H. El-Farra
Abstract A methodology for the design of fault-tolerant control systems for chemical plants with distributed interconnected processing units is presented. Bringing together tools from Lyapunov-based nonlinear control and hybrid systems theory, the approach is based on a hierarchical architecture that integrates lower-level feedback control of the individual units with upper-level logic-based supervisory control over communication networks. The local control system for each unit consists of a family of control configurations for each of which a stabilizing feedback controller is designed and the stability region is explicitly characterized. The actuators and sensors of each configuration are connected, via a local communication network, to a local supervisor that orchestrates switching between the constituent configurations, on the basis of the stability regions, in the event of failures. The local supervisors communicate, through a plant-wide communication network, with a plant supervisor responsible for monitoring the different units and coordinating their responses in a way that minimizes the propagation of failure effects. The communication logic is designed to ensure efficient transmission of information between units, while also respecting the inherent limitations in network resources by minimizing unnecessary network usage and accounting explicitly for the effects of possible delays due to fault-detection, control computations, network communication and actuator activation. The proposed approach provides explicit guidelines for managing the various interplays between the coupled tasks of feedback control, fault-tolerance and communication. The efficacy of the proposed approach is demonstrated through chemical process examples. © 2005 American Institute of Chemical Engineers AIChE J, 2005 [source]


Luteal Characteristics and Progesterone Production on Day 5 of the Bovine Oestrous Cycle

REPRODUCTION IN DOMESTIC ANIMALS, Issue 6 2007
MP Green
Contents In this study we have examined luteal function in non-lactating and late lactation dairy cows on day 5 of the cycle, during the period of the post-ovulatory progesterone rise. Comparison of luteal progesterone content and in vitro synthetic capacity with circulating plasma progesterone demonstrated that circulating progesterone concentration is a function of total luteal activity rather than the activity of individual units of tissue. Incubation of luteal tissue in vitro demonstrated stimulatory activity of LH and IGF-I, and to a greater degree IGF-II, on luteal progesterone synthesis. Finally the study showed no effect of double ovulation on luteal function. Occurrence of double ovulation in 35% of animals was not associated with any difference in luteal function or plasma progesterone concentrations. [source]


Assessment of the results of treatment in individual units through benchmarking of data

COLORECTAL DISEASE, Issue 8 2007
Freddy Penninckx
No abstract is available for this article. [source]