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Default Values (default + value)

Distribution by Scientific Domains
Engineering37%
Life Sciences25%
Business, Economics, Finance and Accounting25%

Selected Abstracts

Using Cpk index with fuzzy numbers to evaluate service quality

INTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 6 2002
Hong Tau Lee
Service quality is measured by customers' satisfaction. Traditionally, the degree of satisfaction is calculated from the data obtained from questionnaires that have been filled by customers directly. The percentile of each different level of a customer's satisfaction is employed to summarize and compare the quality of service provided by different enterprises. This approach does not consider the consistency of the customers' perceptions, thus making comparison difficult. This paper introduces the concept of a process capability index that considers both the average and the consistency of the data simultaneously. Evaluations of service quality are usually vague and linguistic. We use the fuzzy numbers of linguistic variables developed in fuzzy set theory to modify the process capability index, and then apply it to evaluate the quality of a service. The average and consistency of the data obtained from a service quality evaluation are thus considered simultaneously, making the comparison of the performance of service quality easier. Moreover, the value of the index can be applied to help to point out the direction for improving the performance of service quality whenever it is lower than some default value. [source]

Waste management modeling with PC-based model , EASEWASTE

ENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2008
Gurbakhash S. Bhander
Abstract As life-cycle-thinking becomes more integrated into waste management, quantitative tools are needed for assessing waste management systems and technologies. This article presents a decision support model to deal with integrated solid waste management planning problems at a regional or national level. The model is called EASEWASTE (environmental assessment of solid waste systems and technologies). The model consists of a number of modules (submodels), each describing a process in a real waste management system, and these modules may combine to represent a complete waste management system in a scenario. EASEWASTE generates data on emissions (inventory), which are translated and aggregated into different environmental impact categories, e.g. the global warming, acidification, and toxicity. To facilitate a "first level" screening evaluation, default values for process parameters have been provided, wherever possible. The EASEWASTE model for life-cycle-assessment of waste management is described and applied to a case study for illustrative purposes. The case study involving hypothetical but realistic data demonstrates the functionality, usability, and flexibilities of the model. The design and implementation of the software successfully address the substantial challenges in integrating process modeling, life-cycle inventory (LCI), and impact assessment (LCIA) modeling, and optimization into an interactive decision support platform. © 2008 American Institute of Chemical Engineers Environ Prog, 2008 [source]

Estimating metabolic biotransformation rates in fish from laboratory data

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2008
Jon A. Arnot
Abstract A method is proposed for estimating metabolic biotransformation rate constants for nonionic organic chemicals from measured laboratory bioconcentration and dietary bioaccumulation data in fish. Data have been selected based on a quality review to reduce uncertainty in the measured values. A kinetic mass balance model is used to estimate rates of chemical uptake and elimination. Biotransformation rate constants are essentially calculated as the difference between two quantities, a measured bio-concentration factor or elimination rate constant, and a model-derived bioconcentration factor or elimination rate constant estimated assuming no biotransformation. Model parameterization exploits key empirical data when they are available and assumes default values when study specific data are unavailable. Uncertainty analyses provide screening level assessments for confidence in the biotransformation rate constant estimates. The uncertainty analyses include the range for 95% of the predicted values and 95% confidence intervals for the calculated biotransformation values. Case studies are provided to illustrate the calculation and uncertainty methods. Biotransformation rate constants calculated by the proposed method are compared with other published estimates for 31 chemicals that range in octanol,water partition coefficients from approximately 101 to 108 and represent over four orders of magnitude in biotransformation potential. The comparison of previously published values with those calculated by the proposed method shows general agreement with 82% of the estimated values falling within a factor of three. [source]

Putting value of information theory into practice: a methodology for building sequential decision support systems

EXPERT SYSTEMS, Issue 2 2004
Silvano MussiArticle first published online: 7 MAY 200
Abstract: The paper presents a methodology for building sequential decision support systems based on decision theory using value of information (for short, DT-VOI based SDSSs). DT-VOI based SDSSs support decision-makers in difficult problems of sequential decision-making. In particular we consider the problem of building DT-VOI based SDSSs which are capable of supporting decisions in critical situations where (1) making a decision entails knowing the states of some critical hypotheses, and such knowledge is acquired by performing suitable tests; (2) test outcomes are uncertain; (3) performing a test entails, in general, some drawbacks, so that a trade-off exists between such drawbacks and the value of the information provided by the test; (4) performing a test has the side-effect that it changes the expected benefit from performing other tests; (5) exceptional situations alter probability and utility default values. [source]

Ontological modelling of e-services to ensure appropriate mobile transactions

INTELLIGENT SYSTEMS IN ACCOUNTING, FINANCE & MANAGEMENT, Issue 3 2002
Vagan TerziyanArticle first published online: 21 MAR 200
The main goal of this paper is to provide simple ontological support to mobile electronic commerce. The description of an ontology-driven Transaction Monitor (TM) for mobile business applications is considered. The approach is based on the assumption that the transaction management tool can be implemented in a mobile terminal, allowing integration of different distributed external e-services. We use the ontology-based framework for transaction management so that the TM will be able to manage transaction across multiple e-services and we consider management of distributed location-based services as an example of such ontology-based TM implementation. The core of the approach is very simple service ontologies. Ontologies should be ,placed' both in mobile terminals and in e-services. They define common multiple clients,multiple services standards and vocabularies for the use of the names, types, schemas, default values for parameters, atomic service actions with appropriate structure of action's input and output. In our implementation ontologies help to the TM to deal with multiple services during transactions and to simplify the appropriate user interface. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Experience in calibrating the double-hardening constitutive model Monot

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 13 2003
M. A. Hicks
The Monot double-hardening soil model has previously been implemented within a general purpose finite element algorithm, and used in the analysis of numerous practical problems. This paper reviews experience gained in calibrating Monot to laboratory data and demonstrates how the calibration process may be simplified without detriment to the range of behaviours modelled. It describes Monot's principal features, important governing equations and various calibration methods, including strategies for overconsolidated, cemented and cohesive soils. Based on a critical review of over 30 previous Monot calibrations, for sands and other geomaterials, trends in parameter values have been identified, enabling parameters to be categorized according to their relative importance. It is shown that, for most practical purposes, a maximum of only 5 parameters is needed; for the remaining parameters, standard default values are suggested. Hence, the advanced stress,strain modelling offered by Monot is attainable with a similar number of parameters as would be needed for some simpler, less versatile, models. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Approximate knowledge modeling and classification in a frame-based language: The system CAIN

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 6 2001
Colette Faucher
In this article, we present an extension of the frame-based language Objlog+, called CAIN, which allows the homogeneous representation of approximate knowledge (fuzzy, uncertain, and default knowledge) by means of new facets. We developed elements to manage approximate knowledge: fuzzy operators, extension of the inheritance mechanisms, and weighting of structural links. Contrary to other works in the domain, our system is strongly based on a theoretical approach inspired from Zadeh's and Dubois' works. We also defined an original instance classification mechanism, which has the ability to take into account the notions of typicality and similarity as they are presented in the psychological literature. Our model proposes consideration of a particular semantics of default values to estimate the typicality between a class and the instance to classify (ITC). In that way, the possibilities of the typicality representation proposed by frame-based languages are exploited. To find the most appropriate solution we do not systematically choose the most specific class that matches the ITC but we retain the most typical solution. Approximate knowledge is used to make the matching used during the classification process more flexible. Taking into account additional knowledge concerning heuristics and elements of cognitive psychology leads to the enrichment of the classification mechanism. © 2001 John Wiley & Sons, Inc. [source]

Calculated Ultraviolet Exposure Levels for a Healthy Vitamin D Status

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2006
Ann R. Webb
The dangers of overexposure to sunlight have been well publicized, but less attention has been given to an acknowledged benefit of exposure to UV radiation; that being the cutaneous synthesis of vitamin D3. Here we define a standard vitamin D dose on the basis of recently recommended requirements for vitamin D that take account of its risk reduction role in a variety of diseases, and present a web-based tool that enables the reader to calculate associated exposure times for any time and place using either default values or user-selected conditions. Either it is not possible to synthesize vitamin D3 at high latitudes in winter, or the exposure time required to reach a standard dose is sometimes impractical. Where solar UV is sufficient, a risk-benefit analysis of sunburn vs. vitamin D3 synthesis shows that the best time for brief sun exposure is in the middle of the day. For low solar elevation angles common at high latitudes, a fine line exists between adequate UV exposure for vitamin D3 synthesis and a risk of sun burn. [source]